[Defense mechanisms. An essay on defense mechanisms occurring in everyday life, written for the benefit of dental students].
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Defense Mechanisms↗
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[Significance of normal oral flora, particularly group oral streptococci as defense mechanism against infection in healthy individuals (normal defense mechanism by oral Streptococcus group)].
The alpha-streptococci, consisted of normal oral flora mainly, with inhibitory activity against pathogenic microbes in healthy individuals was investigated by group A Streptococcus (indicator strain 6-22 nonmucoid T-12). Rate of alpha-streptococci with inhibitory activity against group A Streptococcus was increased as aging, and the rate in pre-school children was higher than that in school children. These results suggested that more than 90% of the tested alpha-streptococci with strong inhibitory activities (S. salivarius) against indicator strain had inhibitory activities against group A Streptococcus (mucoid T-6), H. influenzae, S. pneumoniae, group C Streptococcus, and from 40% to 70% of the tested strains had also inhibitory activities against other pathogens. As there were many strains of alpha-streptococci with inhibitory activities against pathogens, that usually detected in the upper respiratory infection, the problem on the strains in the future will explain significance of the defense mechanism against upper respiratory infection and this can be applied clinically.
Adolescent↗
[Specific and non-specific defense mechanisms against infection].
Defense mechanisms against bacterial, viral or parasitic infections require the cooperation of effector cells (mainly polymorphonuclear and mononuclear phagocytes) and mediators such as antibodies, complement and lymphokines. Antibodies and some complement components promote the endocytosis of microorganisms whereas lymphokines activate phagocytic cells. Once endocytosed, microorganisms are killed either by oxidative reactions consequent to the respiratory burst, or by the particular conditions and factors that they encounter in phagolysosomes. Intact microorganisms or their degradation products handled by mononuclear phagocytes represent immunogenic moieties which can trigger immunocompetent lymphocytes and induce specific immune responses. Phagocytic cells may have characteristic intrinsic deficiencies that are responsible for prolonged or recurrent infections.
Antibodies, Bacterial↗
Host defense mechanisms in the urinary tract.
In most episodes of urinary tract infection bacteria reach the bladder through the urethra and then may ascend to the kidneys through the ureters. Bacteria periodically enter the female urinary bladder from the urethra in small numbers. Whether infection ensues depends on the virulence and inoculum size of the microorganism and the adequacy of most defense mechanisms. Human urine is frequently inhibitory and sometimes bactericidal for the bacteria that cause urinary tract infection. Inhibition of bacterial growth coupled with voiding serves as a very effective antibacterial defense mechanism. In addition an intrinsic antibacterial defense mechanism has been demonstrated in the rat urinary bladder unrelated to urine flow. The medulla of the kidney is much more susceptible to infection than the cortex mainly related to its high osmolality. Certain abnormalities of the urinary tract interfere with host defense mechanisms and therefore predispose to urinary tract infection or make infection more difficut to eradicate once present. Some of these abnormalities are obstructive or neurological diseases of the urinary tract, vesicoureteral reflux, calculi, certain metabolic, hematologic, and vascular diseases, and pregnancy.
Adult↗
Defense mechanisms and coping behavior in terminal illness. An overview.
Psychosomatic medicine is increasingly concerned with illness behavior, a concept which includes defense mechanisms and coping styles. An attempt was made to compare defensive processes and social adaptation in a group of 31 patients suffering from a probable terminal illness of iatrogenic origin. The surprising degree of conformity between the defense profiles towards the illness and those towards general life stress was found. Reaction-formation and stoicism were the defense mechanisms most often associated with successful defense. Interdependence of several ego measures such as defense against general life stress, defense against illness and social adaptation could be shown in various evaluations. Surprisingly, however, aggravators of illness turned out to be psychologically more stable than minimizers, a result which is in contrast to behavior in nonterminal illness. Theoretical implications of the results are discussed.
Adaptation, Psychological↗
Defense mechanisms of the respiratory membrane.
The success or failure of pulmonary defense mechanisms largely determines the appearance of clinical lung disease. The lung is protected by interlucking systems of nonspecific and specific defenses. Inhaled substrances can be isolated by mechanical barriers or can be physically removed from the lung either by transport up the bronchial mucociliary escalator or by transport through interstitial and lymphatic channels leading to lymph nodes. Substances can be locally detoxified within the lung by interaction with secretory proteins, such as antibodies, or by neutralization and dissolution within phagocytic cells. The pulmonary alveolar macrophage is the central figure in the protection of the respiratory membrane, operating in all 3 of the nonspecific modes of defense and augmented by specific immunologic mechanisms as well. Alterations in macrophage function and physiology may be crucial in determining the effectiveness of pulmonary defense. Recent advances in the cell biology of the alveolar macrophage have led to a greater understanding of its complex funcition. The multiple origins of macrophages from local and circulating cell pools and the variability in their fate and lifespan reflect the multi-faceted role of this cell type. The importance of the interactions between macrophages, orther lung cells, and other defense mechanisms has become increasingly clear. As well as functioning as resident defender of the alveolus, the macrophage is an important effector of the pulmonary immune response and plays a key role in the pathogenesis of a wide variety of inflammatory, destructive, and fibrotic lung diseases. Humoral and cell-mediated immune responses amplify and direct lung defenses against infection and may also participate in protection against other agents. Immunoglobulin A and G, microbial neutralizing and opsonizing anti-bodies, and macrophage-stimulating T lymphocytes are the major immunospecific forms of lung defense. Infectious agents, cigarette smoke, air pollutants, industrial dusts, and a spectrum of coexistent disease states may impair pulmonary defense mechanisms and increase susceptibility to asute and chronic respiratory diseases. A thorough understanding of the ways in which the lung protects itself against the daily assault of infectious, toxic, and immunogenic materials should lead to a beter understanding of pathogenesis and consequences of lung disease and to better clinical care of the patient with respiratory disease.
Animals↗
Host-defense mechanisms in hidradenitis suppurativa.
Host-defense mechanisms were studied in seven patients with active hidradenitis suppurativa (HS). Granulocyte phagocytic function was measured by ingestion of Staphylococcus aureus labeled with radioactive carbon 14 and intracellular killing was determined by bactericidal pour plate method. Chemotaxis was measured by radioactive counting of sodium chromate Cr 51 granulocytes migrating in modified Boyden chambers. Granulocyte adherence was estimated in vitro by filtering blood samples through nylon fiber columns. Cell-mediated immunity was measured by intradermal delayed hypersensitivity responses to Candida, mumps. streptokinase/streptodornase, and purified protein derivative antigens. No abnormality was demonstrated in any granulocyte or cell-mediated immune function tests. Moreover, all patients had normal immunoglobulin levels and elevated total hemolytic complement. Therefore, we conclude that HS is a localized chronic infection of apocrine glands without a generalized defect in host defense.
Adult↗
The defense mechanism of splitting: developmental origins, effects on staff, recommendations for nursing care.
Splitting as a predominant defense mechanism is used by a large number of people. It is characterized by projection of good and bad qualities onto people in the environment and malformed ego functioning. Nurses need to understand the developmental origins, formation of ego deficits and defense mechanism of splitting so that they can care for these people. Effective nursing care is dependent on leadership which anticipates splitting, maintains a cohesive staff group and intervenes appropriately. Limit setting provides the most effective treatment modality as it supplies the missing internal function of the deficient ego. With this use of limit setting staff will prevent splitting and foster socially acceptable behavior. This will have a dual effect of beginning ego reconstruction and increasing self-esteem for the patient and treatment success for the staff.
Adaptation, Psychological↗
Choice of defense mechanisms by Indian and white adolescents.
An analysis of Defense Mechanism Inventory scores from Indian and white adolescents indicated some cultural differences. Differences between white, male-female performance scores were found in all five defense catagories. Differences between Indian, male-female performance scores were found for three of the five defense categories. Indian-white differences were found only for males and involved the two categories of turning against object and reversal. It was concluded that Indian child-rearing practices and culture may foster the development of reversal type defenses and inhibit the development of turning against object type defense within Indian males.
Adolescent↗
The Defense Mechanism Inventory and alcoholics.
The utility of the Defense Mechanism Inventory (DMI) with alcoholic patients was evaluated by reviewing previous research and presenting new data concerning the test characteristics and the relationships between the DMI and various demographic, cognitive, and personality variables. In general, the defense mechansims of projection and turning against others was associated with greater anxiety, depression, and psychopathology. Utilization of the mechanisms of intellectualization and denial were related to lower levels of psychopathology. The construct validity of the DMI was questioned in view of the results obtained, and the utility of the measure for the prediction of treatment response of alcholics was discussed.
Alcoholism↗
Variable effect of encephalomyocarditis virus on host defense mechanisms.
A number of viruses have been shown to suppress a variety of host defense mechanisms. To further define the effect of a viral infection on host resistance, a number of parameters were examined during the course of a lethal encephalomyocarditis virus infection of mice. The peripheral lymphocyte count, the induction of interferon in spleen cells by Newcastle disease virus, and the proportion of B cells in the spleen were all decreased or suppressed. In contrast, the responsiveness of spleen lymphocytes to phytohemagglutinin, the delayed-type skin hypersensitivity to dinitrofluorobenzene, and the proportion of T cells in the spleen remained normal. These results indicate that a viral infection may have divergent effects on different parameters of host resistance and emphasize the need to examine several functions before drawing conclusions about the effect of viral infections on host defense mechanisms.
Animals↗
Shifts in perceptual differentiation and defense mechanisms in alcoholics.
The Group Embedded Figures Test and the Defense Mechanism Inventory were administered to 50 alcoholics approximately 10 days after admission and again after about 6 weeks of treatment. The posttreatment scores on the embedded figures test were significantly higher, more field independent, than initial scores. Ss also had significantly higher scores on the defense of turning against an object and lower scores on reversal when compared to pretreatment scores on the defense inventory. The changes in defensive style were not related to the initial level of or changes in perceptual differentiation.
Alcoholism↗
Foreign policy, ego-defense mechanisms, and balance-of-power vulnerability.
The concept of balance-of-power vulnerability is proposed as a heuristic tool to understand the varying states of anxiety which occur when America's national integrity or security is threatened. Corresponding to the different states of vulnerability are the groups of ego-defense mechanisms which are arranged in a hierarchical pattern. These defense mechanisms are defined as spontaneous or premediated strategies for problem solving, containing elements of intrapsychic and social processes. The Vulnerability-Ego Defense construct is then used to compare America's foreign policy with respect to different nations and with respect to one nation over a protracted period of time.
Anxiety↗
Immunostimulants added to injected Aeromonas salmonicida bacterin enhance the defense mechanisms and protection in rainbow trout (Oncorhynchus mykiss).
Immunostimulants were given to rainbow trout for assaying effects on modulating non-specific defense mechanisms, specific immune response, and protection levels against pathogen challenge with Aeromonas salmonicida. Three drugs, levamisole (an approved veterinary drug in the USA), a quaternary ammonium compound (QAC), and a short-chain polypeptide (ISK) were found to affect the non-specific defense mechanism activities, which were measured by changes in circulatory neutrophil and phagocytic activity levels, and the specific immune response factors, which were measured by numbers of plaque-forming cells, and circulatory antibody levels. When given alone, the immunostimulants elevated the non-specific factors. When injected in combination with an A. salmonicida O-antigen bacterin, the non-specific factors were further elevated, and the specific response was raised over samples taken from fish given the bacterin without the immunostimulants. Challenge tests with the virulent pathogen, A. salmonicida, showed a 5-6 day delay in the onset of mortalities in the fish given the immunostimulants alone, and a 12-14 day delay when immunostimulants given were combined with the bacterin. In the groups given the QAC or ISK with the bacterin, there was a 20% and 40% survival rate, respectively.
Adjuvants, Immunologic↗
The immune response in iron-deficient children: Impaired cellular defense mechanisms with altered humoral components.
Humoral and cellular defense mechanisms were evaluated in 20 children with iron deficiency anemia and in seven with latent iron deficiency. Serum immunoglobulin concentrations, salivary IgA, and total hemolytic complement were within normal range; C'3 concentration was increased. Tests of lymphocyte function showed impaired delayed hypersensitivity skin responses in vivo and decreased in vitro H-3-thymidine incorporation following stimulation with phytohemagglutinin and candida antigen. Tests of neutrophil function showed normal nitroblue tetrazolium dye reduction, decreased bactericidal function, and increased chemotactic activity. These abnormalities could be detected in latent iron deficiency before the development of clinical anemia suggesting that altered immunologic function was an early manifestation of iron deficiency. Normal results were obtained two to three months after iron therapy was begun. The clinical implication of these findings is disucssed in relationship to the reported susceptibility of iron-deficient children to intercurrent infections.
Anemia, Hypochromic↗
The macrophage and host defense mechanisms.
Macrophages participate in a variety of host defense mechanisms. The delivery of macrophage precursors from the bone marrow to the tissues may be reduced with bone marrow failure and macrophage function may be impaired with certain virus infections such as herpes zoster or infectious mononucleosis. Defective macrophage function may impair cell mediated immunity more than humoral immunity which is manifested clinically by cutaneous anergy. One disease associated with chronic macrophage dysfunction is chronic mucocutaneous candidiasis.
Agranulocytosis↗
Identity diffusion and psycho-social defense mechanisms.
This paper attempts to delineate behaviors that can function as "psycho-social" defense mechanisms to ward off temporarily the anxiety and uncertainty of identity diffusion. Four categories are outlined: I. Escapes from identity uncertainty (e.g., immersion in intense immediate experiences); II. Adopting temporary substitute identities (e.g., purchasing items with "ready-made personas"); III. Acting to strengthen temporarily a weak identity (e.g., through risk-taking); IV. Striving to make an identity out of the meaninglessness of identity diffusion itself (e.g., through pointless fads). It is then suggested that one reason for youthful drug abuse is that drugs are so well-suited for providing most of these temporary defenses.
Adolescent↗
Defense mechanisms in men and women alcoholics.
The responses of men and women alcoholics to the Defense Mechanism Inventory showed that the women scored significantly higher in "turning against self" and the men in "turning against others." Although such differences may underlie reported sex differences in the incidence of depression and sociopathic personality disorder, they have also been found in studies of nonalcoholics and psychiatric outpatients.
Adult↗