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Biomedical subjects

K E Nelson

Publications and source records attributed to K E Nelson.

At least 199 records · Page 11Linked to original sources
PubMed1989

Hepatitis B antigen and antibody in patients with leprosy: a study of three resettlement villages in Thailand.

It remains uncertain whether the cellular immune abnormalities of patients with lepromatous leprosy interfere with resolution of hepatitis B virus (HBV) infections. To investigate this question in an area coendemic for the two diseases, we determined the prevalence of hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) in: 1) 204 leprosy patients living in three leprosy resettlement villages; 2) 198 contacts living in the same villages; and 3) 44 newly diagnosed leprosy patients in Thailand. Within the villages, the prevalence of HBsAg positivity was inversely related to age, tended to be more frequent in patients with tuberculoid than lepromatous leprosy, and was similar after age adjustment among persons with and without leprosy. The prevalence of HBV markers found in newly diagnosed patients was similar to that in the villagers. We conclude that extensive HBV transmission had occurred in the resettlement villages and that the natural history of HBV infection was similar in persons with, whether tuberculoid or lepromatous, and without leprosy.

Adolescent↗
PubMed1988

The influence of human immunodeficiency virus (HIV) infection on antibody responses to influenza vaccines.

STUDY OBJECTIVE: To ascertain whether subjects infected with human immunodeficiency virus (HIV) generally develop protective hemagglutination inhibition antibody responses to inactivated influenza vaccines. DESIGN: Prospective study of 104 persons before and after immunization. SETTING: Outpatient clinic and hospital ward. PATIENTS: Persons with the acquired immunodeficiency syndrome (AIDS) (n = 25), AIDS-related complex (n = 14), and HIV-seropositive men with only lymphadenopathy or no symptoms (n = 27). Controls were HIV-seronegative homosexual men (n = 22) and HIV-seronegative heterosexuals (n = 16). INTERVENTIONS: Subjects were immunized with inactivated vaccines containing 15 micrograms of each of the following influenza virus hemagglutinins: A/Taiwan/1/86 (HINI), A/Mississippi/1/85 (H3N2), A/Chile/1/83 (HINI), and B/Ann Arbor/1/86. MEASUREMENTS AND MAIN RESULTS: Fourfold or greater antibody responses occurred less frequently in subjects with HIV infections than in HIV-seronegative controls. Protective levels (1:64 or greater) of hemagglutination inhibition antibodies were attained by 94% to 100% of HIV-seronegative controls, 52% to 89% of HIV-seropositive asymptomatic subjects, and 13% to 50% of subjects with AIDS or AIDS-related complex. No increase in the prevalence or level of serum HIV p24 antigen or clinical deterioration was detected among HIV-infected persons after influenza immunization. CONCLUSIONS: Because of the poor antibody responses to influenza vaccines among HIV-infected subjects, even in many with no or minimal symptoms, alternative strategies for preventing influenza, such as booster doses of influenza vaccine, prophylaxis with amantidine, or both should be considered.

AIDS-Related Complex↗
PubMed1988

Segregation analysis of leprosy in families of northern Thailand.

Sixty-three families with multiple instances of leprosy were identified through a major leprosy treatment center in northern Thailand. Complex segregation analyses for single major genes or polygenic inheritance were performed using the maximum-likelihood routine POINTER to determine the most likely etiologic model of genetic susceptibility. Liability differences between men and women were considered in these models. When individuals were considered to be affected because they had any form of leprosy, a generalized major gene model with nearly dominant parameters on the liability scale, but additive penetrances, was found to be the most likely. When only those individuals who had tuberculoid forms of leprosy were considered to be affected, a recessive model was found to be the most likely; however, the discrimination between various models was poor. Further analyses are necessary to delineate genetic mechanisms to explain these apparently divergent results. In particular, methods of testing two locus models should be considered.

Adult↗
PubMed1988

Tuberculosis, tuberculin reactivity, and delayed cutaneous hypersensitivity in nursing home residents.

When all residents of a 460-bed nursing home were tuberculin tested after discovery of a fatal case of pulmonary tuberculosis, 34% reacted, including 6% who gave boosted reactions. Twenty-four of 262 (9.2%) nonreactors converted to tuberculin reactors 6 months after exposure. Six of the convertors were among the 21% of the residents who were originally considered anergic on the basis of negative Candida and Trichophyton skin tests. These results confirm the observation that aged nursing home residents have lower rates of tuberculin reactivity than earlier in their lives, and that tuberculosis is a nosocomial infection in nursing homes. However, generalized immune senescence cannot be invoked as a reason for apparent susceptibility because the very marker of infection--the development of tuberculin reaction--is evidence of some degree of immune competence. Furthermore, the presence of cutaneous anergy as clinically determined does not predict inability to develop an immune response to the tubercle bacillus.

Aged↗
PubMed1988

Serological studies of patients with cutaneous and oral-oropharyngeal anthrax from northern Thailand.

An outbreak of 52 cases of cutaneous anthrax and 24 cases of oral-oropharyngeal anthrax occurred in rural Northern Thailand in 1982, caused by contaminated water buffalo meat. Microbiologic diagnosis of many of these cases was hindered by delayed presentation for care and by prior antibiotic therapy. In a retrospective investigation, we used enzyme-linked immunosorbent assays to measure antibody titers to components of anthrax edema toxin (edema factor [EF] and protective antigen [PA]), lethal toxin (lethal factor [LF] and PA), and poly-D-glutamic acid capsule. Electrophoretic-immunotransblots (EITB, Western blot) were used to detect antibodies to PA and LF. Nine patients with cutaneous anthrax, 10 patients with oral-oropharyngeal anthrax, and 43 healthy unexposed Thai control villagers were studied. Over all, EITB was positive in 13/18 patients (sensitivity 72%) and 0/43 controls (specificity 100%). The sensitivity of the ELISA was 72% for PA, 42% for LF, 26% for EF, and 95-100% for capsule. Although a few control sera had apparent false positive titers to PA, the specificity of the ELISA confirmed by EITB (100%) demonstrated the applicability of these tests for the diagnosis of anthrax.

Adolescent↗
PubMed1988

Illness beliefs of leprosy patients: use of medical anthropology in clinical practice.

Illness beliefs of 61 patients identified as having leprosy were assessed by Kleinman's Explanatory Model Format. Our patients used a wide variety of etiologic theories which were grouped in categories such as venereal disease, heredity, dangerous food, sin, karma, and humoral disorders. Despite efforts at patient education, very few patients adopted the concept of bacterial infection to explain their illness. The patients identified their illness with a variety of different labels, some of which had associations with particular symptoms. Leprosy was perceived and experienced more as a series of acute disorders not necessarily related to one another. The various theories of illness were instrumental in directing treatment choices which included a number of indigenous healing practices. Such information may be useful in improving patient care and compliance by providing practitioners with interpretive strategies for communicating with their patients.

Adolescent↗
PubMed1987

Cellular and humoral immune response to a phenolic glycolipid antigen (PhenGL-I) in patients with leprosy.

The ability of phenolic glycolipid I (PhenGL-I) of Mycobacterium leprae to stimulate in vitro lymphocyte proliferation (LP) was tested in cultures of peripheral blood cells from 42 patients with leprosy in Chicago and Thailand, 9 individuals with household contact in Thailand, and 10 unexposed North American controls. Only 10 responders (24%) were found among the patients, and the degree of LP was small. Responders were found among patients with lepromatous (18%) or tuberculoid (30%) leprosy without relation to age, complications, duration of treatment, or lepromin responsiveness. The specificity of the response was supported by a lack of response to two other glycolipids, by responses by T cells but not B cells, and by the observation that three of four responders tested maintained their responses to PhenGL-I for at least 1 year. Serum immunoglobulin M (IgM) and IgG antibodies were measured in the same patients by using PhenGL-I or its terminal monosaccharide conjugated to a bovine serum albumin carrier in an enzyme-linked immunosorbent assay. The presence of IgM antibody correlated negatively with LP to lepromin and to PhenGL-I in patients with tuberculoid leprosy. We conclude that circulating T cells from some leprosy patients proliferate in the presence of PhenGL-I in vitro, but the response is weak, possibly due to concomitant suppression or inhibition. The predominance of IgM antibody to PhenGL-I may be related to a lack of a T-helper-cell-mediated switch to IgG antibody response.

Antibodies, Bacterial↗
PubMed1987

Tuberculosis in physicians. Compliance with preventive measures.

Compliance with public health recommendations for tuberculosis control was evaluated by a survey of 4,417 physicians who had not contracted tuberculosis during medical school nor during the 4 decades after graduation through 1981. Thirty-one percent of the cohort had been vaccinated with bacille Calmette-Guérin (BCG) and 47% considered themselves tuberculin-positive. Thirty-two percent of 1,088 physicians who graduated after 1974 had been exposed to 3 or more patients with infectious tuberculosis in the previous year. Fifty-eight percent of 738 unimmunized, tuberculin-negative physicians who had been exposed to one or more patients with infectious tuberculosis in the previous year had tuberculin tests every 1 to 2 yr. Forty-nine percent of 597 unimmunized tuberculin reactors with similar occupational exposure had chest roentgenograms every 1 to 2 yr. The BCG-vaccinated physicians were less likely to have frequent tuberculin tests but no different frequency of chest roentgenograms. Eight percent of 1,460 unimmunized tuberculin reactors received isoniazid chemoprophylaxis, including 39% of 128 tuberculin reactors who graduated after 1974 (the majority of the latter were younger than 35 yr of age). Of 66 physicians who had active tuberculosis during medical school or after graduation, 20 (30%) had not received any antituberculosis chemotherapy, whereas 2 of 46 who did, received chemotherapy only after a second episode of tuberculosis. In summary, our study documents poor compliance by physicians with recommended policies for the prevention of tuberculosis in health care workers.

Antitubercular Agents↗
PubMed1986

Mycobacterium leprae fails to stimulate phagocytic cell superoxide anion generation.

Mycobacterium leprae is an intracellular pathogen that is ingested by and proliferates within cells of the monocyte/macrophage series. Mechanisms by which intracellular pathogens resist destruction may involve failure to elicit a phagocyte "respiratory burst" or resistance to toxic oxygen derivatives and lysosomal enzymes. We have studied the ability of M. leprae and Mycobacterium bovis BCG to stimulate the generation of superoxide anion (O2-) in vitro by human blood neutrophils and monocytes and murine peritoneal macrophages. M. leprae bacteria failed to stimulate significant O2- release except at high bacteria-to-cell ratios (greater than 50:1) whether or not they were pretreated with normal serum or serum from patients with lepromatous leprosy. Either viable or irradiated BCG; on the other hand, stimulated the three cell types to release significant amounts of O2- when challenged with as few as 10 organisms per cell. Serum pretreatment enhanced the release of O2- by the three cell types. Preincubation for 18 h with viable M. leprae did not inhibit the ability of monocytes to respond with an oxidative burst to phagocytic stimuli. The failure of M. leprae to stimulate phagocyte O2- generation may be an important factor in its pathogenicity.

Animals↗
PubMed1986

Tuberculosis in physicians: a continuing problem.

We evaluated the occurrence of active tuberculosis in 4,575 physicians who graduated between 1938 and 1981 from the same medical school. There were 66 cases. Fifteen (23%) cases were detected after 1970 including 4 diagnosed in 1981. For most years, the incidence of tuberculosis was higher in physicians than in the general population. Forty-eight (73%) patients were between 25 and 34 yr of age at the time of diagnosis. Two thirds of all cases occurred within 6 yr of graduation, even in graduates since 1970. The risk of tuberculosis was 140 per 100,000 persons-years within 6 yr of graduation. Sixty-three percent of initially tuberculin-negative medical students who subsequently had active tuberculosis converted their tuberculin reaction during medical school or clinical training. Recipients of BCG vaccine had 40% less tuberculosis than unimmunized, initially tuberculin-negative, physicians. Health authorities should be cognizant of the continuing risk of tuberculosis in medical students and physicians.

Adult↗
PubMed1986

Lymphocyte transformation in lepromatous leprosy: a study of the influence of disease activity and symptom duration.

The lymphocyte hyporesponsiveness to M. leprae of patients with active lepromatous leprosy has been well described. This immune defect is less well understood in terms of its time of origin, possible reversibility and specificity. To further examine the persistence and specificity of this abnormality, lymphocyte transformation tests of 93 leprosy patients to lepromin, BCG and PHA were studied. Among lepromatous patients, a decreased response to M. leprae was seen, whether the disease was active or inactive. Decreased responses to BCG were found in lepromatous patients with active disease, but not in those with inactive disease. The duration of patient symptoms was not associated with differences in LTT responses among the active lepromatous patients.

Adolescent↗
PubMed1985

Transmission of neonatal listeriosis in a delivery room.

Two cases of neonatal listeriosis occurred in a hospital within a two-week period. Both infants were infected with the same organism, Listeria monocytogenes, type 1a, bacteriophage type 6 (lysotype 1652). Both infants were born in the same delivery room, 17 hours apart. The index patient became septic shortly after birth and died after 48 hours despite antibiotic therapy. The mother of the index patient was febrile and had chorioamnionitis. The second infant became ill with meningitis at 13 days of age. Neither infants nor mothers were attended by the same medical or nursing staff nor were they in the same labor or postpartum areas or nurseries. However, both infants were resuscitated in the same delivery room after birth by means of laryngoscope, suction catheter, and emergency resuscitation (Ambu) bag. Although it was hospital policy to clean and sterilize resuscitation equipment after use, the equipment had only been wiped with alcohol between patients in this instance, since sterile replacement equipment was not available during the early-morning hours when the index birth occurred. Therefore, we believe the contaminated resuscitation equipment was the source of infection in the second infant. This episode emphasizes the importance of appropriate disinfection of respiratory resuscitation equipment to prevent nosocomial infection due to L monocytogenes, an unusual but important pathogen in neonates.

Cross Infection↗