What is gangrene? |

Causes and Symptoms

Gangrene involves tissue death (necrosis) due to lack of blood flow or bacterial infection. There are three main types of gangrene: dry gangrene, wet gangrene, and gas gangrene. Dry gangrene
refers to necrosis caused by blood flow interruption without bacterial infection, as from diseases such as diabetes and atherosclerosis that impair the circulatory system. Dry gangrene affects the extremities, most commonly the toes and feet, and presents as dry, shriveled, purplish or blackened skin that looks like it has been mummified. Wet gangrene and gas gangrene, on the other hand, are both caused by bacterial infections. Wet gangrene can be caused by a variety of bacteria that infect damaged tissue following an injury or trauma, such as bedsores or frostbite. The infected tissue can blister or swell and emit a foul-smelling discharge. Wet gangrene is more dangerous than dry gangrene because of the risk of sepsis, or infection spreading to the whole rest of the body, often resulting in death. Gas gangrene is a specific kind of bacterial infection, usually Clostridium perfringens but sometimes Clostridium septicum, that affects deep muscle tissue. It is generally the result of trauma or surgery, although it can occur spontaneously. The infection begins deep beneath the skin, but eventually large patches of skin can turn dark purple and develop large dark blisters. The disease is known for its quick progression, muscle and tissue death, gas production, and, ultimately, sepsis. Not every infected wound will progress to wet or gas gangrene; they occur only if there is sufficient tissue death, as the dead tissue provides an excellent environment for the bacteria to grow and flourish.

With gas gangrene that is the result of surgery or trauma, bacteria enter the body through an opening in the skin. When the involved tissue becomes compromised because of a lack of blood, infection occurs and the process of necrosis begins. Spontaneous gas gangrene occurs when the bacteria spread from the gastrointestinal tract (stomach and intestines) in people with colon
cancer. When there is a small tear in the gastrointestinal tract, the bacteria enter the bloodstream and spread to the muscles. Spontaneous gas gangrene is caused by Clostridium septicum. C. septicum is different from C. perfringens because it can survive and grow in conditions that are aerobic. In both types of gas gangrene, the real cause of the associated problems are the exotoxins that are released. These exotoxins destroy cells, resulting in tissue death that can also affect the heart muscle.

Treatment and Therapy

The usual treatment for gangrene is the removal of dead and dying tissue (a procedure called abridgement), usually surgically, to improve the healing of surrounding tissue. Sometimes skin grafts may be used to repair the damaged area. However, if the damage is too extensive, amputation of the affected digits or limb may be required. In the case of gangrene caused by bacterial infection, an immediate course of intravenous antibiotics is also pursued. Blood thinners may also be administered to prevent blood clots. Gas gangrene is an infectious disease emergency, and the patient should be evaluated immediately. An additional treatment for gas gangrene is a procedure called hyperbaric oxygen therapy, in which the patient is placed in a small chamber that is filled with oxygen at greater than normal atmospheric pressure. This forces more oxygen into the blood, which is detrimental to the growth of Clostridium septicum, because it is an anaerobic bacterium, meaning it thrives in the absence of oxygen.

To prevent gangrene, early wound care is mandatory. The use of antibiotics to prevent infection is also important in the care of a patient who has sustained trauma. Once the diagnosis of gangrene has been made, aggressive management that includes cutting away the dead tissue, managing the basic life support parameters, antibiotics, and surgery if needed, will improve the prognosis. Therefore, the mainstay of treatment is early identification and aggressive treatment.

Bibliography

Carson-DeWitt, Rosalyn. "Gangrene." Health Library, September 30, 2012.

Folstad, Steven G. “Soft Tissue Infections.” In Emergency Medicine: A Comprehensive Study Guide, edited by Judith E. Tintinalli. 6th ed. New York: McGraw-Hill, 2004.

"Gangrene." Mayo Clinic, August 10, 2011.

"Gangrene." MedlinePlus, August 24, 2011.

Urschel, John D. “Necrotizing Soft Tissue Infections.” Postgraduate Medical Journal 75 (November, 1999): 645–649.

Wong, Jason K., et al. “Gas Gangrene.” http://www .emedicine.com/emerg/topic211.htm.

What made Oedipus go insane?

Oedipus scratches out his own eyes when he discovers that he has fulfilled the prophesy of the Oracle of Delphi, who told him that he would kill his own father  and marry his mother. Oedipus had not known that the old man he had fought with and killed while on the road to Thebes was his father, Laius, and that he married his mother, Jocasta, unwittingly. Years before, after hearing his prophecy, Oedipus had assumed...

Oedipus scratches out his own eyes when he discovers that he has fulfilled the prophesy of the Oracle of Delphi, who told him that he would kill his own father  and marry his mother. Oedipus had not known that the old man he had fought with and killed while on the road to Thebes was his father, Laius, and that he married his mother, Jocasta, unwittingly. Years before, after hearing his prophecy, Oedipus had assumed that his father and mother were the man and woman who had raised him, when in fact King Polybus and Queen Merope were his adopted parents, who had taken him in from shepherds who discovered him as an infant, after his father had ordered him executed.

Oedipus realizes all of this too late, after his mother and wife, Jocasta, figures  out what has happened and hangs herself in a frenzy of grief and disgust. So what really drives Oedipus to scratch out his own eyes is the confluence of events of Jocasta's suicide, and the realization that he has unwittingly fulfilled the prophecy that he fled his home to avoid. This cruel irony and the revulsion Oedipus feels at knowing that he has been making love to his mother for years, cause him to scratch his eyes out.

Yet I would caution the reader against assuming that Oedipus' reaction means that he "lost his mind." The situation he finds himself in is horrific and extraordinary. Some might argue that Oedipus' incredibly violent and self-destructive reaction to the discovery that he has committed regicide, patricide and incest, is entirely proportional, and not an over-reaction. In the context of a Greek tragedy, this catharsis is not a signal of psychosis, but an epic punishment that fits a truly epic and tragic crime.

What are developmental stages? |

Physical and Psychological Factors

The development of the human being from infant to child to adolescent to adult is a story of increasing physical, cognitive, social, and emotional adequacy in coping with environmental demands. Major observers of human development have added a key corollary concerning the nature and pace of this development: It occurs in stages.

Development in stages implies several features about the process. The first implication is that developmental changes are not simply quantitative but also qualitative, changes not only in degree but also in kind. With advancement to another stage, perceptions, thoughts, motives, and social interactions are fundamentally altered. A second implication is that development is uneven in its pace—sometimes flowing and sometimes ebbing, sometimes fast and sometimes slow and steady in apparent equilibrium. A third implication is that the order of the stages is invariant: one always moves from lower to higher stages. No individual skips stages; each subsequent stage is a necessary antecedent to the more mature or advanced stages to come. The invariant sequence is preordained by the biological maturation of neurological systems and by the necessary requirements of human societies.

Descriptions of development in terms of stages are found in the writings of many psychologists, especially cognitive psychologists, who are interested in age-related changes in thinking styles, and psychoanalytic psychologists, influenced by Sigmund Freud, who concern themselves with changes in the growing child’s emotional involvements. The most significant, influential, and comprehensive of stage descriptions of development are those of two seminal scientists, Jean Piaget
(1896–1980) and Erik Erikson
(1902–94).

Piaget, a cognitive developmental
psychologist, outlined a series of shifts in children’s cognition, their ways of thinking about and interpreting the world. They include the sensorimotor stage in infancy, the preoperational stage beginning in toddlerhood, the intuitive preoperational substage of the preschool child, the concrete operations stage of the school-age child, and the formal operations stage beginning in adolescence.

Erikson, who updated psychoanalytic theory, outlined a series of age-related shifts in motives and ways of relating to others, each one related to a psychosocial
crisis. These psychosocial stages include an infancy stage of trust versus mistrust, a toddlerhood stage of autonomy versus shame and doubt, a preschool childhood stage of initiative versus guilt, a school-age stage of competence versus inferiority, and an adolescent stage of identity versus role diffusion.

The approaches of Piaget and Erikson originated independently, each emphasizing different aspects of development. The stages that they describe, however, should be viewed as complementary. Since the social changes result in large part from shifts in the child’s thinking, the psychosocial stages of Erikson closely parallel the cognitive stages outlined by Piaget.

In infancy, a period lasting from birth to about eighteen months, sensorimotor cognitive development is initiated by rapid brain development. During the first six months of life, the nerve cells in the forebrain that control coordinated movements, refined sensory discriminations, speech, and intellect increase greatly in number and size and develop a rich network of connections. This neural growth makes possible dramatic progress in the child’s ability to discriminate relevant objects and to coordinate precise movements of arms, legs, and fingers in relating to these objects. The infant who was capable of only a few reflexes at birth by six months can grasp a dangling object. The infant who was born with very poor visual acuity by six months can recognize detailed patterns in toys and faces. The infant shows recognition and knowledge of an object by relating to it repeatedly with the same pattern of movements. During the first few months of life, the infant has very limited ability to recall objects when they
are not directly seen or heard and, in fact, will fail to look for a toy when it is not in view. Sensorimotor integrations, therefore, form the infant’s principal method of representing reality. Only gradually does attention span increase and does the infant acquire the capacity to think about missing objects. The capacity to keep out-of-sight objects in mind, the gradual appreciation of object permanence, is a key achievement of the sensorimotor stage.

The corresponding psychosocial stage of infancy is built around the establishment of trust, some sort of sustaining faith in the stability of the world and the security of human relationships. Crucial to the establishing of this trust is the stability of the infant’s relationship with a primary caregiver, most commonly a mother. Babies begin to pay special attention to the caregiver on a schedule determined by their cognitive development. The primary caregiving adult is among the first significant objects identified by the infant. Indeed, it appears that infants are wired to be especially responsive to a human caregiver. Infants of only two or three months of age find the human face the most interesting object and will focus on faces and facelike designs in preference to almost any other stimulus object. By the age of six months, infants clearly recognize the caregiver as special but for some time cannot appreciate that the caregiver continues to exist during absences. Thus, conspicuous anxiety sometimes occurs when the caregiver leaves.

It is little wonder that an infant perceives the caregiver as special. The human caregiver is wonderfully reinforcing to the infant. Relief from all kinds of pain, smiling responses to infantile smiles, vocal responses to infant babbling, soft and warm cuddling contact, and games all offer to the infant what is most craved. By six to nine months of age, the baby seems dependent on the caregiver for a basic feeling of security. Until the age of two or three, most infants seem more secure when their mother or primary caregiver is physically present. The relationship between the quality and warmth of infant-mother interactions and the infant’s feelings of security has been supported by voluminous research on mother-infant attachment.

By about age two, neural and physical developments make possible the advance to more adaptive styles of cognitive interpretations. Piaget characterized the cognitive stage of toddlerhood as preoperational. Brain centers important for language and movement continue to develop rapidly. Now the child can deal cognitively with reality in a new way, by representing out-of-sight and distant objects and events by words, images, and symbols. The child can also imitate the actions of people not present. Thinking during this stage remains limited. The child cannot yet hold several thoughts simultaneously in mind and manipulate them—that is, perform mental operations. This stage is, therefore, “preoperational.”

Erikson described the psychosocial crisis of toddlerhood as autonomy versus shame and doubt. This crisis results in part from the child’s cognitive growth. The preoperational child has acquired an increasing ability to appreciate the temporary nature of a caregiver’s absence and to move about independently. The toddler can now assert autonomy and often does so emphatically. Resistance to parental demands is possible, and the toddler seems to delight in such resistance. “No” becomes a favorite word. Since this period corresponds to the time when children are toilet trained, parent-child tugs-of-war often involve issues of bowel control and cleanliness. The beginning of shame, the humiliation that comes from overextending freedom foolishly and making mistakes, begins to serve as a self-imposed check on this autonomy.

Piaget characterized the thinking of three-, four-, and five-year-olds as “intuitive.” This thinking is still preoperational. Children can represent to themselves all sorts of objects but cannot keep these objects in the focus of attention long enough to classify them or consider how these objects could be regrouped or transformed. If six tin soldiers are stretched into three groups of two, the preschool child assumes that there are now more than before. Thinking is egocentric because children lack the ability to put themselves in the perspective of others while keeping their own perspective. Yet preschool children make all sorts of intuitive attempts to fit remembered events and scenes into underlying plots or themes. Fanciful attempts to understand events often result in misconstruing the nature of things. Children at this stage are easily misled by appearances. A man in a tiger suit could become a tiger; a boy who wears a dress could become a girl and grow up to be a mother. Appearance becomes reality.

Erikson characterized the corresponding psychosocial stage of the preschool child as involving the crisis of initiative versus guilt. The child’s new initiative is expressed in playful exploration of fanciful possibilities. Children can pretend and transform themselves in play as never before and never again. From dramatic play, the child’s conceptions of the many possibilities of the world of bigger people are enacted. The earlier psychoanalyst, Freud, focused particularly on how children experience their first sexual urges at this time of life and sometimes weave into their ruminations fantastic themes of possession of the opposite-sex parent and jealous triumph over the same-sex parent. To Erikson, such themes are merely examples of the many playful fantasies essential to later, more realistic involvements.

Piaget characterized the cognitive stage of the school-age child as the concrete operations stage. The child is capable of mental operations. The school-age child can focus on several incidents, objects, or events simultaneously. Now it is obvious that six tin soldiers sorted into three pairs of two could easily be transformed back into a single group of six. Regardless of grouping, the total quantity is the same. The formerly egocentric child becomes cognitively capable of empathetic role taking, of assuming the perspective of another person while keeping the perspective of the self in mind. In making ethical choices, the child can now appreciate the impact of alternative possibilities on particular people in particular situations. The harshness of absolute dictates is softened by empathetic understanding of others.

Erikson characterized the psychosocial crisis of the school-age child as one of competence versus inferiority. Now is the time for children to acquire the many verbal, computational, and social skills that are required for adequate adulthood. Learning experiences are structured and planned, and performances are evaluated. Newly empathetic children are only too aware of how their skill levels are perceived by others. Adequacy is being assessed. The schoolchild must not only be good but also be good at something.

The cognitive stage of the adolescent was described by Piaget as formal operational. The dramatic physical changes that signal sexual maturity are accompanied by less obvious neural changes, especially a fine tuning of the frontal lobes of the brain, the brain’s organizing, sequencing, executive center. Cognitively, the adolescent becomes capable of dealing with formal operations. Unlike concrete operations, which can be visualized, formal operations include abstract possibilities that are purely hypothetical, abstract strategies useful in ordering a sequence of investigations, and “as if” or “let us suppose” propositions.

Erikson’s corresponding psychosocial crisis of adolescence was that of identity versus role diffusion. The many physical and mental changes and the impending necessity of finding occupational, social, marital, religious, and political roles in the adult world impel a concern with the question, “Who am I?” To interact as an adult, one must know what one likes and loathes, what one values and despises, and what one can do well, poorly, and not at all. Most adolescents succeed in finding themselves—some by adopting the identity of family and parents, some after a soul-searching struggle.

Disorders and Effects

Stage theories define success as advancement through the series of stages to maturity. Psychosocially, each successful advance yields a virtue that makes life endurable: hope, will, purpose, competence, and finally fidelity to one’s own true self. As a final reward for normal developmental success, one can enjoy the benefits of adulthood: intimacy, or the sharing of one’s identity with another, and generativity, or the contribution of one’s own gifts to the benefit of the next generation and to the collective progress of humankind. Cognitively, maturity means the capacity for formal operational thought. Hypothetical thinking of this type is basic to most fields of higher learning, to the sciences, to philosophy, and even to the comprehension of such abstract moral principles as justice.

Advancement to each subsequent stage of cognitive development is dependent on both neurological maturation and a culture that presents appropriate problems. Adults who fail to attain concrete operational thought are considered intellectually disabled. A failure in neurological maturation is a frequent cause. Failures to attain formal operational thought, on the other hand, are not unusual among normal adults. Cultural experience must nourish advancement to formal operational thinking within a domain of inquiry by the provision of moderately novel and challenging but not overwhelming tasks. When people are not confronted with such complex problems within some domain, then abstract, formal operational thought fails to occur. Abstract ethical reasoning is a case in point. Cross-cultural studies suggest that concepts of justice that involve the application of abstract rules are rare in cultures where people seldom confront questions of ethical complexity.

Psychosocial pathology is evidenced by development arrested in one of the immature stages of psychosocial development. It results from a social environment that fails to foster growth or exaggerates the particular apprehensions that are most acute in one of the developmental stages.

The development of trust in infancy requires a loving, available, and sensitive caretaker. If the infant’s caretaker is unavailable, missing, neglectful, or abusive, the pathology of mistrust develops. The world is perceived as unstable. Close personal relationships are viewed as unreliable, fickle, and possibly malicious. Later, closeness in relationships may be rejected. Confident exploration of the possibilities of life may never be attempted.

Similarly, the apprehensions of each subsequent psychosocial stage can be exaggerated to the point of pathology. The toddler, shamed out of troublesome expressions of autonomy, may compensate for doubts with the rigidly excessive controls of the compulsive lifestyle. The preschool child can become so overwhelmed with guilt over playful fantasies, particularly sexual and aggressively tinged fantasies, that adult possibilities become severely restricted. The school-age child can become so wounded by humiliations in a harshly competitive school environment that the child becomes beaten down into enduring feelings of inferiority. An adolescent may so fear the risks of exploring the possibilities of life that future adulthood becomes a shallow diffusion of roles, a yielding to social pressures and whims unguided by any knowledge of who one really is.

The successful confrontation of the tasks of adulthood—finding a partner to share intimacy and caring for the next generation—are most easily attainable for adults who have overcome each of these earlier developmental hurdles.

Perspective and Prospects

Stage theories of development are found as early as 1900 in the work of American psychologist James Mark Baldwin and in Freud’s psychoanalysis. Baldwin, much influenced by Charles Darwin’s theory of evolution by natural selection, hypothesized that the infant emerges from a sensorimotor stage of infancy to a symbolic mode of thinking, an advancement yielding enormous evolutionary advantages. Freud, the Viennese psychoanalyst, based his conception of emotional development on what he called psychosexual stages. Progression occurs from an oral period of infancy, when sensory pleasure is concentrated on the mouth region, to an anal stage of toddlerhood, when anal pleasures and the control of such pleasures become of concern. When sexual pleasure shifts to the genital region in the three-year-old, the love of the opposite-sex parent becomes sexually tinged, and the child becomes jealous of the same-sex parent. Working through these so-called Oedipal fantasies was, to Freud, crucial to the formation of personality.

Neither Baldwin nor Freud and his followers were the sort of rigorous scientists most respected by scientific psychology in the mid-twentieth century. Far more influential in American psychology between 1920 to about 1960 were behavioral conceptions of the developmental process as steady, incremental growth. To behaviorists such as B. F. Skinner, becoming an adult was conceived as a process of continuously being reinforced for learning progressively more adequate responses.

The stage approaches of Piaget and Erikson were introduced to most American psychologists in 1950, the year that both Piaget’s Psychology of Intelligence and Erikson’s Childhood and Society were published in English. Piaget’s description of cognitive stages was much more complete than Baldwin’s earlier account and was much better supported by clever behavioral observations. Erikson’s thesis of psychosocial stages incorporated most of Freud’s observations about stages. Erikson treated the social environmental pressures intrinsic to each stage as events of primary importance and shifts in the locus of bodily pleasures as secondary.

By the 1970s, Piaget’s and Erikson’s accounts of stages were awarded an important place in most developmental texts. This influence occurred for several reasons. First, researchable hypotheses were derived, and most of this research was supportive. Cross-cultural comparisons suggested that these stages could be found in a similar sequence in differing cultures. Second, the theses of Piaget and Erikson were mutually supportive. The stage-related cognitive changes, in fact, would seem to explain the corresponding psychosocial concerns. Finally, these approaches generated productive spinoffs in related theory and research. In 1969, basing his work on the cognitive changes outlined by Piaget, Lawrence Kohlberg elaborated a stage sequence of progressively more adequate methods of moral reasoning. In 1978, basing her work on Erikson’s hypotheses about trust, Mary Ainsworth began a productive research program on the antecedents and consequents of stable and unstable mother-infant attachment styles.

The most recent challenges to cognitive and psychosocial stage theory arise from the alternative perspectives of biopsychology and information-processing theory. Some psychologists argue that biologically rooted temperament, rather than the social environment, affects both styles of attachment and identity formation. Not only do babies respond to caregivers, but caregivers respond to babies as well. A baby who begins with a shy, passive temperament may be more susceptible to an avoidant attachment style and more likely to elicit detached, unresponsive caregiver behavior. Temperament, it is maintained, is more important than psychosocial environment.

Information processing theorists have challenged the discontinuity implied by stage concepts. They suggest that the appearance of global transformations in the structure of thought may be an illusion. Development is a continuous growth of efficiency in processing and problem solving. The growing child combines an expanding number of ideas, increases the level and speed of processing by increments, and learns more effective problem-solving strategies. To select particular points in this continuous development and call them “stages,” they argue, is purely arbitrary.

The final research to settle the question of the ultimate nature of stages has not been performed. A psychosocial stage theorist can acknowledge the role of temperament but still maintain that loving, trust-creating environments are also significant in encouraging the child to apply temperamental potential in positive social directions rather than in angry antagonism or frightened withdrawal. At the very least, Piagetian and Eriksonian stage concepts have the practical usefulness of highlighting significant developmental events and interpersonal reactions to these events. The warmth of caregivers for infants, the later tolerance of children’s struggles to become themselves, and environments that present challenging problems appropriate to the child’s developmental level are vital to emotional and intellectual growth.

For some purposes, it may be instructive to break the achievement of cognitive and emotional growth into increments that can be seen as if under a microscope. For other purposes, it is instructive to go up for an aerial view to gain perspective on the nature and direction of such achievements. The aerial view is the contribution of stage theories of development.

Bibliography

Berk, Laura E. Child Development. 9th ed. Boston: Pearson/Allyn & Bacon, 2013.

Bukatko, Danuta, and Marvin W. Daehler. Child Development: A Thematic Approach. 6th ed. Belmont, Calif.: Wadsworth/Cengage, 2012.

Charlesworth, Rosalind. Understanding Child Development. 8th ed. Belmont, Calif.: Wadsworth/Cengage, 2011.

Feldman, Robert S. Development Across the Life Span. 6th ed. Upper Saddle River, N.J.: Pearson/Prentice Hall, 2011.

Ginsburg, Herbert, and Sylvia Opper. Piaget’s Theory of Intellectual Development. 3d ed. Englewood Cliffs, N.J.: Prentice Hall, 1988.

Hall, Calvin S., Gardner Lindzey, and John B. Campbell. Theories of Personality. 4th ed. New York: John Wiley & Sons, 1998.

Karen, Robert. “Becoming Attached.” Atlantic Monthly 265, no. 2 (February, 1990): 35–70.

Miller, Patricia H. Theories of Developmental Psychology. 5th ed. New York: Worth, 2011.

Nathanson, Laura Walther. The Portable Pediatrician: A Practicing Pediatrician’s Guide to Your Child’s Growth, Development, Health, and Behavior from Birth to Age Five. 2d ed. New York: HarperCollins, 2002.

Parke, Ross D., et al., eds. A Century of Developmental Psychology. Washington, D.C.: American Psychological Association, 1994.

Sternberg, Robert J. Psychology: In Search of the Human Mind. 3d ed. Fort Worth, Tex.: Harcourt College, 2001.

Whitebread, David. Developmental Psychology and Early Childhood Education. London: Sage, 2011.

Why did Timothy create a carving of Stew Cat in The Cay by Theodore Taylor?

Timothy creates a carving of Stew Cat because he thinks Stew Cat is bad luck. He calls him a "jumbi." Voodoo was something many of the Black people from the islands believed in and practiced.

"Recalling everything that had happened, Timothy said, 'He (Stew Cat) came board d'raff, an' we got separated from all else; den d'young bahss' eyes got dark, gibbin' us exceedin' trouble; den we float up dis hombuggin' Debil's Mout'...'" (Taylor 81).

Timothy is convinced that Stew Cat is the cause of all their troubles and bad luck. 

The next day, when Phillip gets up, he cannot find Timothy. Phillip takes his cane and begins to look for Timothy, finally finding him on the north side of the cay.

Phillip asks where Stew Cat is, and at first Timothy doesn't answer, but when Phillip persists, Timothy very unconvincingly tells Phillip that Stew Cat is probably out hunting lizards. 

Phillip can hear Timothy working on something and when he asks what it is, Timothy tells him that he's just "Cuttin' on an ol' piece of wood" (Taylor 83).

The two of them go back to the hut to eat breakfast, and then Timothy leaves again. Phillip looks for Stew Cat and tries to figure out what to do.

Eventually, Phillip discovers that Timothy had been carving a large cat with nails in it designed to "kill the evil jumbi" (Taylor 85). Stew Cat has been on the raft all this time, but is now back on the island, and Timothy believes that the Stew Cat carving will change their luck.

Describe a metaphor from the poem "New Face" by Alice Walker

The poem New Face by Alice Walker describes the speaker's reactions to falling in love. The speaker describes overcoming their worry about falling in love, instead choosing to fully honor, understand, and appreciate the experience. There are multiple metaphors in the poem, but one example is the following:

The source appears to besome inexhaustible spring

In the context of the poem, this is assessing the source of the "rush of feelings" which the speaker...

The poem New Face by Alice Walker describes the speaker's reactions to falling in love. The speaker describes overcoming their worry about falling in love, instead choosing to fully honor, understand, and appreciate the experience. There are multiple metaphors in the poem, but one example is the following:

The source appears to be
some inexhaustible spring

In the context of the poem, this is assessing the source of the "rush of feelings" which the speaker feels as they are beginning to fall in love. Describing the source of emotion as a spring is a metaphor because it is a comparison between two unlike things that is not literally true. The speaker describes the spring as "inexhaustible," conveying that the supply of love and source of emotions as infinite. Additionally, the title of the poem is a metaphor, as shown in the poem's final lines:

The new face i turn up to you
no one else on earth
has ever
seen

The development of new feelings and love for another person does not literally make one's face different, but the speaker utilizes metaphor to describe how falling in love can change someone. The "new face" is the result of new feelings, and the result of the experience and emotion of falling in love.

What is an oncology clinical nurse specialist?

Subspecialties: The oncology nurse clinical specialist may choose to specialize in a particular cancer practice working with a selected population of patients. Examples of specialties include medical hematology oncology, hematology oncology, outpatient radiation, outpatient hematology oncology, outpatient pediatric oncology, and palliative care.

Cancers treated: Depends on area of specialty

Training and certification: The oncology clinical nurse specialist completes a bachelor’s degree in nursing and a master’s degree in nursing with appropriate clinical practicum from an accredited graduate nursing program. Education programs will vary, but the master’s degree generally takes about two years to complete and requires at least five hundred hours of clinical practicum. Required courses for a master’s degree vary from school to school. Courses included in these programs are advanced physiology and cancer pathophysiology, pharmacology, cancer genomics, epidemiology, disease and symptom management, palliative care, nursing research, nursing and medical ethics, public policy, leadership, health care financing, health program planning and evaluation, technology use, and advanced nursing concepts. Practicum hours are usually accrued in the nurse’s chosen specialty.

Additional training and skills necessary to effectively practice in the role of oncology clinical nurse specialist include crisis management, in-depth knowledge of the chosen clinical cancer specialty, maturity to take responsibility for patients’ lives, understanding of medical ethics, teaching proficiency, and expertise in interpersonal relations to work with the patient, caregivers, and multidisciplinary health care team. Oncology clinical nurse specialists must have valid nursing licenses issued by the boards of nursing in their states.

In some states, oncology clinical nurse specialists must also receive certification by successfully completing examinations in their specialty. In other states, attaining certification status is voluntary. Proficiency is validated through examination based on predetermined standards and given by a nongovernment agency. The Oncology Nursing Certification Corporation provides several different certifications for nurses working with cancer patients. The Advanced Oncology Certified Clinical Nurse Specialist (AOCNS) certification examination is available to professional nurses who hold a current, active license that is nonrestricted, have completed a master’s degree or higher from an accredited school of nursing, and have completed a minimum of five hundred hours of supervised clinical practice in oncology nursing. Documentation of the supervised clinical practicum hours is required and verified before certification is granted. AOCNS certification is valid for four years. The AOCNS nurse can renew certification three ways: combining practice hours and professional development points, combining practice hours and a successful test result, or combining professional development points and a successful test result.

Services and procedures performed: Oncology clinical nurse specialists can work in a variety of settings, including hospitals (acute care), clinics, long-term care or elder care homes, home care or hospice agencies, and private and joint practices. They can also work as consultants. The oncology clinical nurse specialist recognizes and values the expanding and evolving nature of cancer care and remains current with complex services, procedures, and treatments. The services and procedures performed depend on the setting and function of the nurse’s specific role.

Some oncology clinical nurse specialists work as clinicians and provide direct care for patients and caregivers. They often work alongside other health care professionals such as physicians, nurses, and therapists to plan and evaluate patient care. These nurse specialists schedule and coordinate diagnostic and therapeutic procedures or tests for oncology patients. They will monitor the test results and revise the cancer patient’s care plan based on individual and changing needs. At a cancer care clinic or oncology hospital unit, the oncology clinical nurse specialist may perform the initial admission assessment for new patients and develop the plan of care. This nurse will monitor the plan of care and make adjustments as indicated for the individual cancer patient. The nurse assists with discharge planning to include referrals for other community resources or establish follow-up appointments to physicians’ offices or cancer care clinics.

Oncology clinical nurse specialists often function as teachers. In clinical settings, these nurses keep abreast of current research and new therapies. They use their expanded knowledge of cancer and cancer treatment to teach new concepts or treatment modalities to staff members and members of the multidisciplinary health care planning team. In the hospital cancer unit or cancer care clinic, oncology clinical nurse specialists help assess current staff education, develop new educational strategies, coordinate educational agendas, and revise teaching programs. Educational programs are provided as in-service programs or as clinical practicums. They serve as advisers to staff and other professionals. The goal of this education is to organize and implement an educational strategy that trains professional caregivers to provide the best possible cancer care for patients and their caregivers.

Cancer care education is critical for the cancer patient, family, and caregivers to live life to the fullest. The oncology clinical nurse specialist builds a relationship with the cancer patient and caregivers and provides individualized patient teaching. Cancer patients need accurate and up-to-date information about their disease and treatment options to make decisions about their care. The highly educated and informed oncology clinical nurse specialist is often the person who spends time with the patient and family, teaching them necessary components of self-care and disease management. Even after discharge from the hospital cancer care unit, the patient and caregivers may contact the oncology clinical nurse specialist with questions and concerns. The positive relationship developed during hospitalization often carries over to the home setting as the oncology clinical nurse specialist fills the role of consultant and educator.

Administrative functions are sometimes part of the services delivered by oncology clinical nurse specialists. They monitor the medication regimen of the cancer patient and suggest changes when needed for improved patient outcomes. Sometimes they manage the research protocol as primary investigator for grants and clinical studies. Oncology clinical nurse specialists are stewards in fiscal management of resources by keeping an eye on cancer care costs, noting where services can be delivered more efficiently.

Related specialties and subspecialties: Oncology clinical nurse specialists can work in a number of subspecialties depending on their interests and the positions available in the nurses’ area. Roles are evolving and diverse, as the oncology nurse clinical specialist contributes many skills to the health care team. Some assume administrative roles and perform in high levels of leadership within the cancer care settings. For example, oncology clinical nurse specialists can become nurse managers over specialized hospital oncology units or serve as directors of community cancer care centers, or they might become health care administrators for managed care or insurance companies and consult with key decision makers about covered services for cancer care patients.

Oncology clinical nurse specialists can pursue further education and receive a doctorate degree in various academic fields. One example is the oncology clinical nurse specialist who completes a doctorate and enters the field of cancer research. Another nurse might earn a doctorate in nursing science or a doctorate in education and join a university graduate faculty to teach others to become oncology clinical nurse specialists. As faculty, these nurses can work as consultants and mentors to undergraduate nursing students to help them become proficient in cancer care. Some pursue additional education to function in the dual role of oncology clinical nurse specialist and nurse practitioner. Still others assume an entrepreneurial spirit and use their knowledge and skills in creative and innovative private and joint practice.

Bibliography

Blaseg, Karyl D., Penny Daugherty, and Kathleen A. Gamblin. Oncology Nurse Navigation: Delivering Patient-Centered Care across the Continuum. Pittsburgh: Oncology Nursing Society, 2014. Print.

Camp-Sorrell, Dawn, and Rebecca A. Hawkins. Clinical Manual for the Oncology Advanced Practice Nurse. 3rd ed. Pittsburgh: Oncology Nursing Society, 2014. Print.

Carper, E., and M. Hass. “Advanced Practice Nursing in Radiation Oncology." Seminars in Oncology Nursing 22.4 (2006): 203–11. Print.

Skilbeck, J., and S. Payne. “Emotional Support and the Role of Clinical Nurse Specialists in Palliative Care.” Journal of Advanced Nursing 43.2 (2003): 521–30. Print.

Yarbro, Connie Henke, Debra Wujcik, and Barbara Holmes Gobel. Cancer Nursing: Principles and Practice. 7th ed. Sudbury: Jones, 2011. Digital file.

Yarbro, Connie Henke, Debra Wujcik, and Barbara Holmes Gobel. Oncology Nursing Review. 5th ed. Sudbury: Jones, 2012. Print.

Zuzelo, Patti R. Clinical Nurse Specialist Handbook. Sudbury: Jones, 2007. Print.

Organizations and Professional Societies

National Association of Clinical Nurse Specialists
.


http://www.nacns.org, 100 N. 20th Street, 4th floor, Philadelphia, PA 19103.

Oncology Nursing Certification Corporation
.


http://www.oncc.org, 125 Enterprise Drive, Pittsburgh, PA 15275.

Oncology Nursing Society
.


http://www.ons.org, 125 Enterprise Drive, Pittsburgh, PA 15275.

What is immunology? |

Science and Profession

The field of immunology deals with the ability of the immune system to react against an enormous repertoire of stimulation by antigens. In most instances, these antigens are foreign infectious agents such as viruses or bacteria. Inherent in this process is the ability to react against nearly any known determinant, whether natural or artificially produced. The most reactive antigenic determinants are proteins, though to a lesser degree, other substances such as carbohydrates (sugars), lipids (fats), and nucleic acids may also stimulate a response.

In general, the body exhibits tolerance during the constant exposure to its own tissue. The precise reasons behind tolerance are vague, but the basis for the lack of response lies in two major mechanisms: the elimination during development of immunological cells capable of responding to the body’s own tissue and the active prevention of existing reactive cells from responding to self-antigens. When this regulation fails, autoimmune disease may result.

There are two major types of immunological defense: humoral immunity and cell-mediated immunity. Humoral immunity refers to the soluble substances in blood serum, primarily antibody and complement, while cellular immunity refers to the portion of the immune response that is directly mediated by cells. Though these processes are sometimes categorized separately, they do in fact interact with and regulate each other.

Antibodies are produced by cells called B lymphocytes in response to foreign antigens. These proteins bind to the antigen in a specific manner, resulting in a complex that can be removed readily by phagocytic white blood cells. More important in the context of autoimmunity, antibody-antigen complexes also activate the complement pathway, a series of some twenty enzymes and serum proteins. The end result of activation is the lysis of the antigenic targets. In general, the targets are bacteria; in autoimmune disease, the target may be any cell in the body.

The cellular response utilizes any of several types of cytotoxic cells. These can include a specialized lymphocyte called the T cell (so named because of its development in the thymus) or another unusual type of large granular lymphocyte called the natural killer (NK) cell. NK and cytotoxic T cells function in a similar manner—by binding to the target and releasing toxic granules in apposition to its cell membrane.

Though autoimmune diseases differ in scope, they do tend to exhibit certain common factors. The pathologies associated with most of these illnesses result in part from the production of autoantibodies, which are antibodies produced against the body’s own cells or tissues. If the antibody binds to tissue in a particular organ, complement is activated in the tissue, causing the destruction of those regions of the organ. For example, Goodpasture’s syndrome is characterized by the deposition of autoantibodies directed against the membrane of the glomerulus in the kidneys. Complement activation can result in severe organ pathology and subsequent kidney failure.

If the autoantibody binds to soluble material in blood serum, the resultant antibody-antigen complexes are carried along in the circulation, and there is the possibility that they will lodge in various areas of the body. For example, systemic lupus erythematosus (SLE) results from the production of autoantibodies against soluble nucleoprotein, which is released from cells as they undergo normal death and lysis. The immune complexes frequently lodge in the kidney, where they can cause renal failure.

This is not to say that all autoimmune diseases result solely from autoantibody production. Though a precise role for either cytotoxic T cells or NK cells in human autoimmune disease has not been fully confirmed, several observations make such an association likely. First, large numbers of T cells are found in certain organ-specific diseases, including thyroiditis and pernicious anemia. Second, animal models of similar diseases show a specific role for such cells in the pathology of these diseases. Thus, it is likely that these cells do participate in the organ destruction.

Autoimmune disorders can be categorized in the form of a disease spectrum. At one end of the spectrum one can place organ-specific diseases. For example, Hashimoto’s disease is an autoimmune thyroid disorder characterized by the production of autoantibodies against thyroid antigens. The extensive infiltration and proliferation of lymphocytes is observed (although, as described above, their roles are unproved), along with the subsequent destruction of follicular tissue.

Likewise, diabetes mellitus, type 1 (formerly called juvenile-onset diabetes) may be an organ-specific autoimmune disease. In this case, however, autoantibodies are directed against the beta cells of the pancreas, which produce insulin. In pernicious (or megaloblastic) anemia, antibodies are produced against intrinsic factor, a molecule necessary for uptake of vitamin B12. Subsequent pathology results from lack of absorption of the vitamin. Addison’s disease, from which US president John F. Kennedy suffered, is a potentially life-threatening condition resulting from antibody production against the adrenal cortex. Myasthenia gravis is characterized by severe heart or skeletal muscle weakness caused by antibodies directed against neurotransmitter receptors on the muscle. In fact, cells from any organ may be potential targets for production of an autoantibody.

Certain organ-specific autoimmune diseases in the spectrum are characterized not by antibodies directed against any specific organ, but by cellular infiltration triggered in some manner by less specific autoantibodies. For example, biliary cirrhosis, an inflammatory condition of the liver, is characterized by the obstruction of bile flow through the liver ductules. Though extensive cellular infiltration is observed, serum antibodies are directed against mitochondrial antigens, which are found within all cells. Certain types of chronic hepatitis also exhibit an analogous situation.

In some cases, antibodies may be directed against circulatory cells. Antibodies directed against red blood cells may cause subsequent lysis of the cells, leading to hemolytic anemia. Often, these are temporary conditions that have resulted from the binding of a pharmacologic chemical such as an antibiotic to the surface of the cell, which triggers an immune response. A more serious condition is hemolytic disease of the newborn (HDN), one example being erythroblastosis fetalis, or Rh disease. In this case, a mother lacking the Rh protein on her blood cells may produce an immune response against that protein, which is present in the blood of the fetus she is carrying during pregnancy. Prior to 1967, when an effective preventive measure became available, HDN was a serious problem for many pregnancies. Antibodies directed against blood platelets can cause a reduction in the number of those cells, resulting in thrombocytopenia purpura. An analogous situation can be seen with other cell types.

At the other end of the autoimmune spectrum are those diseases that are not cell- or organ-specific but result in widespread lesions in various parts of the body. Lupus received its name from the butterfly rash often seen on the faces of patients, which resembles a wolf bite (lupus is Latin for “wolf”). Pathologic changes can be found at various sites in the body, however, including the kidneys, joints, and blood vessels. Likewise, rheumatoid arthritis is characterized by the production of rheumatoid factor, an antibody molecule directed against other antibodies in blood serum. The resultant immune complexes lodge in joints, causing the joint pain and destruction associated with severe arthritis.

In most cases, the specific reason for the production of autoantibodies is unknown. Genetic factors are certainly involved, since some autoimmune diseases run in families. Some may be triggered by bacterial or viral infections. Viral antigens may be expressed on the surfaces of certain cells, or the virus itself may be attached to the cell. Heart muscle appears to express antigenic determinants in common with certain streptococcal bacteria. A mild “strep throat” may be followed several weeks later by severe rheumatic fever.

The binding of drugs to cell surfaces may trigger an immune response. For example, penicillin may bind to the surfaces of red blood cells, triggering a hemolytic anemia. Likewise, sedormid may bind to the membrane of platelets.

Most cases of autoimmune disease, however, are triggered by no apparent cause. They may “simply” involve a breakdown of the normal regulatory mechanisms associated with the immune response.

Diagnostic and Treatment Techniques

The regulation of self-reactive lymphocytes is necessary for the maintenance of tolerance by the immune system. When regulation breaks down or is otherwise defective, either humoral or cellular immunity is generated against the cells or tissues. The resultant pathology may be simply a painful nuisance or may have potentially fatal consequences. The difference relates to the extent of damage to particular organs, in the case of organ-specific autoimmune reactions, or to the level of tissue damage in systemic disease.

Despite differences in pathology, the mechanisms of tissue damage are similar in most autoimmune diseases. Most involve the formation of immune complexes. Either antibodies bind to cell surfaces or immune complexes form in the circulation. In either case, the result is complement activation. Components of the complement pathway, in turn, can either directly damage cell membranes or trigger the infiltration of a variety of cytotoxic cells.

Because the damage associated with most autoimmune diseases results from parallel processes, methods of treatment vary little in theory from one illness to another. Most involve the treatment of resultant symptoms; for example, the use of aspirin to reduce minor inflammation and, when necessary, the use of steroids to reduce the level of the immune response. Recently, the focus has shifted from treating symptoms only to attacking the underlying disease mechanism with disease-modifying drugs. Some of these drugs include methotrexate, azathioprine, cyclosporine, and hydroxychloroquine. Newer immune modulators (such as infliximab and etanarcept) and monoclonal antibodies (such as rituximab) are used in some autoimmune conditions that are refractory to other measures.

The treatment of autoimmune diseases does not eliminate the problem. The disease remains, but under ideal conditions, it is held under control. At the same time, there exists the danger of side effects of treatment. For example, most methods that reduce the level of the immune response are nonspecific; reducing the severity of the autoimmune disease may cause the patient to become more susceptible to infections by bacteria or viruses.

Certain approaches have been successful in the palliative treatment of some forms of autoimmune disease. For example, patients with myasthenia gravis (MG) exhibit significant muscle weakness. A myasthenia gravis patient may have difficulty breathing and may experience extreme fatigue, in severe cases being unable to open his or her mouth or eyelids. Associated with the disease are autoantibodies produced against the receptor for the neurotransmitter
acetylcholine (ACh), the chemical utilized by nerves in regulating movement by the muscle. By blocking the ACh receptor, these antibodies inhibit the ability of nerves to control muscle movement. In effect, the patient loses control of the muscles.

Patients with myasthenia gravis often exhibit abnormalities of the thymus, the gland associated with T-cell production. In addition, there is evidence that the thymus contains ACh receptors that are particularly antigenic (perhaps exacerbating the illness). Removal of the thymus, even in adults, often aids in reducing the symptoms of the disease. The thymus, though not superfluous in adults, carries out its main functions during the early years of life, through adolescence. Thus, its removal generally has few major implications.

Often, MG will respond to more conventional forms of treatment. Steroid treatment will often reduce symptoms. Metabolic controls may also aid in reducing symptoms. For example, during normal nerve transmission of ACh, the enzyme cholinesterase is present to break down ACh, thereby regulating muscle movement. The use of anticholinesterase drugs to prolong the presence of ACh at the site of the receptor on the muscle has also been of benefit to some patients.

Systemic lupus erythematosus is among the most common of systemic autoimmune diseases. The disease usually strikes women in the prime of life, between the ages of twenty and forty. It is characterized by a butterfly rash over the facial region and by weakness, fatigue, and often a fever. In many respects, the symptoms are those of severe arthritis. As the disease progresses, tissue or organ degradation may occur in the kidney or heart.

The specific cause of the symptomology is the formation of immune complexes, which consist of antibodies against cell components such as DNA or nucleoprotein. Complexes in the kidney have been large enough to observe with the electron microscope, particularly when the complexes contain cell nuclei. Similar complexes have been observed in regions of the skin characterized by inflammation and a rash. The immune complexes are sometimes ingested (phagocytized) by scavenger neutrophils, which make up the largest proportion (65 percent) of white blood cells. The presence of these so-called LE cells, white cells with ingested antibody-bound nuclei, was at one time used for the diagnosis of lupus.

As is true for many autoimmune diseases, the control of lupus involves the use of steroids and other immunosuppressive drugs. These have included drugs such as cyclosporin, which blocks T-cell function, and antimitotic drugs such as azathioprine or methotrexate, which block the proliferation of immune cells, as well as immune modulators such as rituximab. Generalized immunosuppression as a side effect is a concern. Often, using combinations of steroids and immunosuppressives makes it possible to use lower concentrations of each, increasing the drugs’ effectiveness and reducing the danger of toxicity.

Other palliative treatments of symptomology can increase patient comfort. For example, aspirin may be used to reduce inflammation or joint pain. Topical steroids can reduce the rash. Since lupus may significantly increase the photosensitivity of the skin, staying out of direct sunlight, or at least covering the surface of the skin, may reduce skin lesions. It should be emphasized again that these treatments deal only with symptoms; none will cure the disease.

Since some systemic diseases result from immune complex disorders, a reduction of the levels of such complexes has been found to be beneficial to some patients. Treatment involves a process called plasmapheresis. Plasma, the liquid portion of the blood, is removed from the patient (a small proportion at a time), after which the immune complexes are separated from the plasma. Though a temporary measure, since additional complexes continue to form, the process does prove useful.

Rheumatoid arthritis is another common autoimmune disorder. As is true of most autoimmune diseases, rheumatoid arthritis is primarily a disease of women. Symptomatology results from the lodging of immune complexes in joints, resulting in the inflammation of those joints. Many cases result from the formation of antibodies directed against other antibody molecules—a case of the immune system turning against itself. Pathology results both from complement activation and from the infiltration of a variety of cells into the joint; the result is damage to both cartilage and bone.

Medical treatment usually begins with aspirin or other nonsteroidal anti-inflammatory agents. Other common treatments are those that increase patient comfort: rest, proper exercise, and weight loss, if necessary. In severe cases, steroids, immune modulators, or monoclonal therapy may be necessary.

In general, autoimmune diseases are characterized by alternating periods of symptomatology and remission. Treatments are generally similar in their approach of reducing inflammation as the first line of intervention, with the use of immunosuppression being the last resort. Since the precise origin of most of these disorders is unknown, prevention remains difficult.

Perspective and Prospects

During the 1950s, Macfarlane Burnet published his theory of clonal selection. Burnet believed that antibody specificity was predetermined in the B cell as it underwent development and maturation. Selection of the cell by the appropriate antigen resulted in proliferation of that specific cell, a process of clonal selection.

Burnet also had to account for tolerance, however— the inability of immune cells to respond against their own antigens. Burnet theorized that during prenatal development, exposure to self-antigens, or determinants, resulted in the abortion of any self-reactive cells. Only those self-reactive immune cells that were directed against sequestered antigens survived.

Though Burnet’s theories have reached the level of dogma in the field of immunology, they fail to account for certain autoimmune disorders. In the “correct” circumstances, the body does react against itself. Though they were not recognized at the time as such, autoimmune disorders were recognized as early as 1866. In that year, W. W. Gull demonstrated the link between chilling and a syndrome called paroxysmal hemoglobinuria. When external tissue such as skin is exposed to cold, large amounts of hemoglobin are discharged into the urine. In 1904, Karl Landsteiner and Julius Donath established the autoimmune basis for the disease by demonstrating the role of complement in the lysis of red blood cells, causing the release of hemoglobin and the symptomatology of the disorder. Furthermore, they demonstrated that one could cause the lysis of normal cells by mixing them with sera derived from hemoglobinurics. Together the published the first immunohematolgic test, known as the Donath-Landsteiner test.

Hashimoto’s disease was among the first organ-specific autoimmune diseases to be described. The disease was first described in 1912 by Hakaru Hashimoto, a Japanese surgeon, and the immune basis for the disease was established independently by Ernest Witebsky and Noel Rose in the United States, and by Deborah Doniach and Ivan Roitt in Great Britain, in 1957.

Since the 1950s, dozens of autoimmune disorders have been described. Treatment of these disorders remains, for the most part, nonspecific. Research in the area, in addition to attempts to define the precise trigger for autoimmune disease, has attempted to develop ways to suppress specifically those immune reactions responsible for the symptomatology. Successes have been associated with vaccines directed against components involved with the reactions under investigation. For example, since the production of autoantibodies is the basis for some forms of disease, the generation of additional antibody molecules directed against determinants on the autoantibodies at fault could serve to neutralize the effects of those components. This procedure could be likened to a police department that arrests its own dishonest officers. There is a precedent for such an operation. Newborn children of mothers suffering from myasthenia gravis synthesize just such antibodies against the inappropriate MG antibodies that have crossed the placenta. Synthesis does seem to ameliorate the symptoms of the disease.

There is no question that autoimmune disorders represent an aberrant form of immune response. Nevertheless, an understanding of the underlying mechanism will shed light on exactly how the immune system is regulated. For example, it remains \\unclear how antibody production is controlled following a normal immune response. In the presence of an antigen, antibody levels increase for a period of days to weeks, reach a plateau, and then slowly decrease as additional production comes to a halt. The means by which the shutdown takes place remains nebulous.

Tolerance does not result solely from an absence of T or B cells that respond to antigens—it involves an active suppression of the process. A more detailed understanding of the process will lead to a more thorough understanding of the immune system in general.

Bibliography

Abbas, Abul K., Andrew H. Lichtman, and Pillai Shiv. Cellular and Molecular Immunology. 8th ed. Philadelphia: Elsevier/Saunders, 2015. Print.

Delves, Peter J., et al. Roitt’s Essential Immunology. 12th ed. Hoboken: Wiley, 2011. Print.

Fettner, Ann Giudici. Viruses: Agents of Change. New York: McGraw, 1990. Print.

Frank, Steven A. Immunology and Evolution of Infectious Disease. Princeton: Princeton UP, 2002. Print.

Hertl, Michael. Autoimmune Diseases of the Skin: Pathogenesis, Diagnosis, Management. 3rd ed. Wien: Springer, 2011. Print.

Janeway, Charles A., Jr., et al. Immunobiology: The Immune System in Health and Disease. 6th ed. New York: Garland, 2005. Print.

Kindt, Thomas J., Richard A. Goldsby, and Barbara A. Osborne. Kuby Immunology. 6th ed. New York: Freeman, 2007. Print.

Male, David, et al. Immunology. 8th ed. Philadelphia: Elsevier, 2013. Print.

Parham, Peter. The Immune System. 4th ed. New York: Garland, 2015. Print.

Rose, Noel R., and Ian. R. Mackay, eds. The Autoimmune Diseases. 5th ed. St. Louis: Academic Press/Elsevier, 2014. Print.

Schneider, Matthias, and Klaus Kruger. "Rheumatoid Arthritis—Early Diagnosis and Disease Management." Deutsches Aerzteblatt International 110.27–28 (2013): 477–84. Print.

Sompayrac, Lauren M. How the Immune System Works. Hoboken: Wiley, 2012. Print.

What are the dependent, independent, and controlled variables of a simple pendulum?

Experiments are conducted to study the effect of change in a parameter on some other measurable parameter, while keeping other parameters in check. The parameter which is varied is the independent variable. The parameter which is measured and which changes as a result of change in the independent variable is the dependent variable. The parameter which is not allowed to vary is known as the controlled variable. 

In the experiment involving simple pendulum, we often...

Experiments are conducted to study the effect of change in a parameter on some other measurable parameter, while keeping other parameters in check. The parameter which is varied is the independent variable. The parameter which is measured and which changes as a result of change in the independent variable is the dependent variable. The parameter which is not allowed to vary is known as the controlled variable. 

In the experiment involving simple pendulum, we often study the effect of various parameters on the time period of the pendulum. The time period of the pendulum is given as:

`T = 2pi sqrt(L/g)`

Thus, we can think of the time period as the dependent variable. We often vary the length of the pendulum (L) in such experiments, and hence length of pendulum is the independent variable. We use the same setup, same material of string, same way of doing the experiment (same protocol), same altitude (so that value of g is same in all the experiments) and hence these all are controlled variables.

Note that in some experiments, effect of change in pendulum's mass is also studied and in those cases, mass of pendulum is also an independent variable.

Hope this helps.

What does the "way" represent in The Way to Rainy Mountain?

We can consider Momaday’s use of “the way” to have several different meanings; and yet, they seem to converge into a cohesive one by the end of the book. The Kiowa, his Native American ancestors, once migrated from the Yellowstone valley of the upper Rockies to the Black Hills of North Dakota, and then on to the American Plains and to southwestern Oklahoma, toward a rounded hill called Rainy Mountain. Momaday retraces this journey as...

We can consider Momaday’s use of “the way” to have several different meanings; and yet, they seem to converge into a cohesive one by the end of the book. The Kiowa, his Native American ancestors, once migrated from the Yellowstone valley of the upper Rockies to the Black Hills of North Dakota, and then on to the American Plains and to southwestern Oklahoma, toward a rounded hill called Rainy Mountain. Momaday retraces this journey as a personal pilgrimage – a “way” -- in order to learn more about his people through his own visceral and on-the-ground experience. They made their “way”; now he makes his. He also shares some of the relevant legends that have been passed down through the generations. These stories are a “way” of reminding the people where they came from and what is important to their culture. This book is also a “way” to pay tribute to Aho, the author’s grandmother, who was his last living link to the traditional native days. Merged together, the journeys and the legends and Momaday’s reactions to them combine in order for him to finally find his strong ties to the Kiowas of the past. His way “to” their ways is one that also goes “back.”

What is hyperhidrosis? |

Causes and Symptoms

The purpose of perspiration is to keep the body at an ideal temperature. The sweat glands

are affected by the sympathetic branch of the autonomic nervous system. Two types of sympathetic nerve fibers affect sweat glands: the noradrenergic, which respond to emotional stimuli, and the cholinergic, which respond to temperature. Hyperhidrosis refers to sweating that is greater than is needed to keep the body at a normal temperature.

Hyperhidrosis may be due to a secondary cause, such as hyperthyroidism, hormonal treatments, obesity, menopause, or severe psychiatric disorders. The immediate cause of primary hyperhidrosis (not attributable to another disorder or condition) is dysfunction of the sympathetic branch of the autonomic nervous system; however, the underlying cause of the dysfunction is not clear.

Hyperhidrosis may affect the entire body (general), or it may affect only specific areas, such as the armpits (axillary), palms of the hands (palmar), soles of the feet (plantar), or face (facial). General hyperhidrosis may be a variation on normal sweating. Paroxysmal localized hyperhidrosis, periodic excessive perspiration in a particular area of the body, may also occur. A genetic predisposition may be present. Persons who are obese are more likely to be affected, as are people with certain forms of eczema. Hyperhidrosis can also occur following frostbite.

Hyperhidrosis can vary in severity from being merely embarrassing to quite disabling. It tends to begin in adolescence and gradually increase with age.

Treatment and Therapy

Topical prescription antiperspirants applied to the affected areas may control the symptoms. Drugs that block the sympathetic portion of the autonomic nervous system may also be used. Some people with localized sweating respond to iontophoresis, a technique in which the affected area is placed in an electrolyte solution and stimulated with low-level electrical current. Some success has been shown with injections of botulinum toxin (Botox) into the affected areas. This technique has considerable disadvantages, however. Repeated injections are needed, and they are both painful and costly. Furthermore, the injections may cause temporary weakness of the hand muscles. Surgery to the affected areas of the nervous system has a 90 percent success rate for excessive sweating of the palms but is accompanied by numerous complications, including wound infection, sweating with eating (gustatory sweating), and recurrent hyperhidrosis. Little evidence exists for the effectiveness of psychotherapy, hypnosis, acupuncture, and herbal or homeopathic remedies.

Bibliography:

American Medical Association. American Medical Association Family Medical Guide. 4th rev. ed. Hoboken, N.J.: John Wiley & Sons, 2004.

Carruthers, Jean, and Alastair Carruthers, eds. Botulinum Toxin: Procedures in Cosmetic Dermatology. 3d ed. London: Saunders/Elsevier, 2013.

Carson-DeWitt, Rosalyn. "Hyperhidrosis." Health Library, September 30, 2012.

Haider, Aamir. “Hyperhidrosis: An Approach to Diagnosis and Management.” Dermatology Nursing 16, 6 (December 1, 2004): 515–518.

"Hyperhidrosis (Excessive Sweating)." Mayo Clinic, September 21, 2012.

Komaroff, Anthony, ed. Harvard Medical School Family Health Guide. New York: Free Press, 2005.

Kreyden, O. P., R. Böni, and G. Burg, eds. Hyperhidrosis and Botulinum Toxin in Dermatology. New York: S. Karger, 2002.

Stoppard, Miriam. Family Health Guide. London: DK, 2006.

Why is Mr. Underwood's editorial defending Tom Robinson surprising?

Mr. Underwood's editorial is surprising because it suggests a change of opinion, even a major character change on his part.

Mr. Braxton Bragg Underwood runs Maycomb's only newspaper, The Maycomb Tribune. His most notable action in the story, prior to writing the editorial, was hiding out in his office, covering Atticus with a shotgun when the lynch mob approaches the jail to kill Tom Robinson. Atticus remarks the next morning that these actions are...

Mr. Underwood's editorial is surprising because it suggests a change of opinion, even a major character change on his part.

Mr. Braxton Bragg Underwood runs Maycomb's only newspaper, The Maycomb Tribune. His most notable action in the story, prior to writing the editorial, was hiding out in his office, covering Atticus with a shotgun when the lynch mob approaches the jail to kill Tom Robinson. Atticus remarks the next morning that these actions are surprising, as Underwood "despises Negros, won't have one near him" (Chapter 16). Already, Underwood seems to be undergoing a change of heart and weighing his racism with his sense of justice. This internal struggle seems to have some resolution when Underwood writes the editorial. It seems that at least one man has had his prejudices challenged and changed during the course of the novel.  

I'm halfway finished, but I just want to make sure that I'm doing it right. Please find the current through resistor `R_2` on the attached image...

One of the ways to find the current through the resistor `R_2` is by considering the Kirchoff's Law and the junction rule for currents in the given circuit.

In order to write the Kirchoff's Law, let's assume that the current `I_1`  through `R_1` is directed to the right, the current `I_2`  through `R_2` is directed down, and the current `I_3` through `R_3` is also directed to the right.

Note that while the circuit is not...

One of the ways to find the current through the resistor `R_2` is by considering the Kirchoff's Law and the junction rule for currents in the given circuit.

In order to write the Kirchoff's Law, let's assume that the current `I_1`  through `R_1` is directed to the right, the current `I_2`  through `R_2` is directed down, and the current `I_3` through `R_3` is also directed to the right.

Note that while the circuit is not drawn as closed, all the grounded branches of the circuit have the same potential (zero), so they could be considered connected in one point.

Then, for the left loop

`V_(s1) - I_1R_1 - I_2R_2 = 0`  (1)

and for the right loop

`V_(s2) +I_3R_3 - I_2R_2 = 0`  (2)

The junction rule for the currents: `I_1 = I_2 + I_3` (The current entering the junction equals the sum of the currents leaving the junction).

Plugging in the given values gives us the system of equations that can be solved for `I_2` :

`100I_1 +100I_2 = 10`  (1)

`100I_2 - 100I_3 = 5`  (2)

`I_1 - I_2 - I_3 = 0`  (3)

Simplify the equation (1) by dividing both sides by 10:

`10I_1 + 10I_2 = 1`

Now, let's multiply the equation (3) by -10 and combine it with (1) in order to eliminate `I_1` :

`-10I_1 + 10I_2 + 10I_3 = 0`

Adding (1) and (3) results in

`20I_2 + 10I_3 = 1` (4)

Now solve this together with (2): `20I_2 - 20I_3 = 1` :

Multiply (4) by 2:

`40I_2 +20I_3 = 2` (4)

`20I_2 - 20I_3 = 1`  (2)

Adding these equations together results in

`60I_2 = 3` , so this means `I_2 = 3/60 = 1/20 = 0.05 A` . Since the result is positive, the original choice of direction (down) was correct.

The current through resistor R2 is down and it equals 0.05 A.

How do living things affect one another?

Living things affect one another both positively as well as negatively, depending upon their interactions.

Positive effects:

Living things may interact in a mutualistic manner, where all the interacting species benefit. Butterflies pollinate flowers. This way, the butterflies get their nectar, while the flower is able to spread its pollen and potentially reproduce. Vultures clean up the rotting bodies of animals and help in the recycling of the nutrients by ingesting them. Decomposers also help...

Living things affect one another both positively as well as negatively, depending upon their interactions.

Positive effects:

Living things may interact in a mutualistic manner, where all the interacting species benefit. Butterflies pollinate flowers. This way, the butterflies get their nectar, while the flower is able to spread its pollen and potentially reproduce. Vultures clean up the rotting bodies of animals and help in the recycling of the nutrients by ingesting them. Decomposers also help in nutrient recycling, thereby making the nutrients available for other organisms. 

Negative effects:

In a predator-prey relationship, the predator gains, while the prey loses. Thus, the presence of deer is beneficial for the wolf, but not the other way around. Many organisms also compete among each other for the same resources, such as shelter, food, etc. Since resources are limited, only some organisms will be able to get them. In this way, organisms negatively impact the lives of other organisms. 

Hope this helps.

What are surgical procedures? |

Indications and Procedures

Surgery
has progressed as rapidly as other areas of medicine. Early surgeries consisted of gross excision (the cutting out of abnormal or diseased tissue). Today, surgery has been transformed by scientific advances so that surgeons commonly use microscopes, lasers, and endoscopes that allow the surgeon to make small incisions in order to gain access to the surgical site. Modern operations are much more precise and emphasize repair or replacement rather than excision.

When a patient requires surgery, several preoperative procedures are performed to increase the chances of a successful outcome. First, the patient is asked to abstain from eating for at least eight hours prior to surgery. This action reduces the chances of the individual vomiting during surgery and aspirating the gastric contents into the trachea (windpipe). After arriving at the hospital or clinic, the patient removes his or her clothes and puts on a gown, allowing the medical staff easy access to the patient for catheter insertion, intravenous line insertion, monitor placement, and preparation of the surgical site. Next, an intravenous (IV) line is placed in a vein of the hand or arm and connected to a bottle or bag of solution, which is suspended above the level of the patient’s arm. The intravenous line gives the physician rapid vascular access for sampling blood and injecting drugs. Just before the actual surgery, the patient is usually given a sedative by an anesthesiologist, and electrocardiogram (ECG or EKG) leads and a
blood pressure cuff are applied to the patient to monitor heart rate, heart rhythm, and blood pressure. The anesthesiologist will then anesthetize the patient further while the surgical team begins to prepare the site for the operation. Preoperative antibiotics may be given if there is a significant risk of infection.

The surgery may require either general anesthesia

, in which the patient is unconscious, or local anesthesia, in which a specific region of the body is anesthetized. For general anesthesia, the patient will be injected with an intravenous anesthetic and quickly intubated, a procedure in which a tube is inserted into the trachea and attached to a ventilator. This arrangement gives the anesthesiologist the ability to administer gaseous drugs such as nitrous oxide and halothane as well as to control the patient’s breathing. Surgical assistants prepare the operative site by cleansing the skin with a disinfectant. A sterile drape is used to cover all areas of the body except the surgical site. Surgeons and assistants must mask themselves and prepare for surgery by thoroughly washing their hands and arms. They then carefully put on a sterile gown and gloves. At this point, they must not come into contact with anything nonsterile.

The surgeon uses a scalpel to make an incision through the skin and any underlying structures in order to gain access to the area of the body needing attention. When blood vessels are cut, bleeding must be controlled by cauterizing, clamping, tying off with sutures, or applying direct pressure to the vessel; this process is known as hemostasis.

After the surgery, the incision sites are closed with sutures, and the anesthetic is reversed. The patient is then taken to a recovery room to be monitored closely. Routine care of the patient recovering from anesthesia includes repeated evaluation of body temperature, pulse, blood pressure, and respiration. Postoperative pain medication (such as meperidine, morphine, or fentanyl) is given as needed.

Uses and Complications

Complications from surgery can result from surgical errors, infections, and abnormal patient reactions to the procedure or medications (idiosyncratic reactions). Occasionally, surgery involves damage to healthy tissues, including nerves and blood vessels. Significant intraoperative blood loss may also occur, requiring transfusion. An incision into any part of the body provides an opportunity for bacteria to enter and infect the surgical wound; prophylactic antibiotics help reduce the chance of surgical infection. Rarely, a patient may have an unexpected response to the procedure or drugs, which could result in permanent disability or death. These very infrequent reactions may include a blood clot causing a stroke or heart attack, an abnormal heart rhythm, or severe allergic reactions to medication.

Perspective and Prospects

Modern surgery includes the use of surgical implants, microsurgery, laser surgery, endoscopic surgery, and transplant surgery. Surgical implants are used to replace a part of the body with an artificial implant. These implants include joints, heart valves, eye lenses, and sections of blood vessels or of the skull. During microsurgery, the surgeon uses specially designed instruments and a microscope to perform an operation on minute structures such as blood vessels, nerves, and parts of the eyes or ears. Microsurgery is also being used to reattach severed fingers and toes. Laser surgery utilizes a high-energy, narrow beam that can cut through tissues like a scalpel but that also cauterizes blood vessels during the incision. Lasers can be used on the retina, skin blemishes, and even tumors. Recovery from endoscopic surgery, in which a fiber-optic tube is inserted into the body to view the surgical site, is generally faster than from conventional operations because a smaller incision is made and less tissue damage results. Endoscopes are used to remove stones from the urinary tract and gallbladder and to remove or repair damaged cartilage in joints. With the availability of drugs that suppress tissue rejection, damaged organs can now be surgically replaced by donated organs. The most common examples are the heart, lungs, liver, kidneys, and bone marrow.

Bibliography

Brunicardi, F. Charles, et al., eds. Schwartz’s Principles of Surgery. 9th ed. New York: McGraw-Hill, 2010.

Leikin, Jerrold B., and Martin S. Lipsky, eds. American Medical Association Complete Medical Encyclopedia. New York: Random House Reference, 2003.

MedlinePlus. "Surgery." MedlinePlus, June 17, 2013.

Mulholland, Michael W., et al., eds. Greenfield’s Surgery: Scientific Principles and Practice. 5th ed. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins, 2011.

Zollinger, Robert M., Jr., and Robert M. Zollinger, Sr. Zollinger’s Atlas of Surgical Operations. 9th ed. New York: McGraw-Hill Co., 2011.

What is bioinformatics? |

Introduction

The answer to the question “What is bioinformatics?” is not straightforward, yet in addressing this question the richness and extent of the field become clear. Part of the reason that it is difficult to give a concise definition of bioinformatics is that, as researchers publishing in the field realize, the definition is somewhat artificial and its boundaries are still expanding. This is not surprising, as bioinformatics might also be called mathematical/computational molecular biology, which points to large parts of biology taking on the aspects of a “hard” science such as physics or chemistry.

The creation of bioinformatics was triggered by a combination of factors in the 1990s. Key elements were progress in computing power, the existence of much larger data sets, and increasingly quantitative approaches to molecular biology, including molecular evolutionary studies. The large data sets came from a number of sources, including long individual DNA sequences (for example, genomes), large between-species comparative or evolutionary alignments, microarray-generated gene expression data, proteomics data from two-dimensional gel electrophoresis and mass spectroscopy techniques, and structural information—broadly speaking, the fields of comparative, functional, and structural genomics. It was also increasingly recognized that quantitative molecular biology required vast amounts of computer power not only to assemble genomes but also to complete fundamental analyses, such as aligning related DNA sequences or building a tree from such an alignment. For example, with just twenty sequences there are more different trees relating these sequences than Avogadro’s number (approximately 6 times 1023), and every tree must be checked to ensure that the optimal solution has been found.

The Scope of Research

Bioinformatics itself touches on other areas of science such as biomedical informatics, computer science, statistical analysis, molecular biology, and mathematical modeling. In turn, each of these fields contributes uniquely to the progress of bioinformatics toward a mature science. Equally definitive of bioinformatics is recognizing those areas wholly or partly subsumed by an approach mixing computing power with mathematical and statistical modeling to solve biological questions based on molecular data. These areas include genomics, evolutionary biology, population genetics, structural biology, microarray gene expression analysis, proteomics, and the modeling of cellular processes plus systems biology (for example, modeling a neurological pathway in which individual neurons respond to molecular events).

In bioinformatics, as in chemistry and physics, there is a fundamental split between empirical/experimental and theoretical science. At one extreme may be a laboratory focusing on generating large amounts of microarray data with relatively little analysis, and at the other extreme may be a mathematician working alone to solve a theorem with an application to better analyze that microarray data. It is clear that both approaches are needed for science to develop. However, it is not uncommon to find researchers actively tackling both problems (for example, gathering large data sets and seeking better methods to analyze them). Increasingly, the scale and cost of major bioinformatics projects call for a new model of interdisciplinary biological research in which biologists, statisticians, computer scientists, chemists, mathematicians, physicians, and physicists interact closely together.

The nature of bioinformatics research highlights the need for interdisciplinary skills in modern biology. Some universities issue bioinformatics degrees based on their own formulas. A more direct approach is to require a quadruple major in statistics, computer science, mathematics, and biology. The importance of such a background is that, for example, someone who is not the best mathematician still needs to know how to ask the best mathematicians for help with the problems that inevitably crop up in research in this area. A good example of this interdependence arose in the Celera Genomics effort to complete the human genome, in which mathematicians with a specialty in tiling algorithms were essential to reassembling the millions of sequenced fragments.

In the future, bioinformatics will be increasingly involved with projects, the magnitude of which are technically and intellectually as challenging as anything previously faced in science. For example, a key problem might be a complete computer model of a single cell. Perfection would be achieved only when a biologist could not tell the difference between real and experimental data when the cell experienced a change internally or externally.

Perspective and Prospects

The implications of bioinformatics for medicine are enormous. The strictly informatics side is already central to medical genetics. Databases of human characteristics, including detailed medical histories and biochemical profiles, are matched up with millions of genetic markers within each individual. Only through such enormous databases can statistical sleuths uncover the basis of most diseases that are caused by multiple genes. This is the population genetics of humans on a vast scale. Elsewhere, medical research such as cancer modeling is rapidly becoming a branch of bioinformatics, driven by the fact that cancer is caused by many interacting genes. Bioinformatics is key to the advancement of clinical genomic medicine and genomic technologies affecting complex diseases and disorders, drug dosing, and vaccine design.

The overall prospect is that bioinformatics will make possible a different sort of medicine in the twenty-first century in which fundamental research leads to pharmaceutical intervention, which leads to treating a disease at its root cause in a way that avoids the need for surgical intervention. Treatments of tomorrow, from diagnosis to cure, will involve processing large amounts of data via computers, with doctors remaining the key to ensuring an appropriate treatment regime, one that is personalized and precise, with the consent and comfort of the patient foremost.

In short, one answer to the question “What is bioinformatics?” is the development of virtual molecular biology. As time passes, this scientific endeavor will propagate upward and outward to meet other major areas of biology, such as physiology and ecology. Eventually, much of biology and medicine may come to rest solidly on the same principles as chemistry and physics, yet require major computational resources because of the complexity of the models needed to approximate reality reliably.

Bibliography

Brazas, Michelle D., et al. “ A Quick Guide to Genomics and Bioinformatics Training for clinical and Public Audiences.” PLoS Computational Biology. 10.4 (2014): 1–6. Academic Search Complete. Web. 17 Feb. 2015.

Campbell, A. Malcolm, and Laurie J. Heyer. Discovering Genomics, Proteomics, and Bioinformatics. 2d ed. San Francisco: Pearson/Benjamin Cummings, 2007.

Davidson, Eric H. The Regulatory Genome: Gene Regulatory Networks in Development and Evolution. Boston: Academic Press/Elsevier, 2006.

Higgs, Paul G., and Teresa K. Attwood. Bioinformatics and Molecular Evolution. Malden: Wiley-Blackwell, 2013.

International Human Genome Sequencing Consortium. “Initial Sequencing and Analysis of the Human Genome.” Nature 409, no. 6822 (2001): 860–921.

National Institute of Allergy and Infectious Disease. “Bioinformatics.” National Institutes of Health, May 24, 2013.

Pevsner, Jonathan. Bioinformatics and Functional Genomics. 2d ed. Malden: Wiley-Blackwell, 2013.