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Biomedical subjects

V Schauf

Publications and source records attributed to V Schauf.

At least 19 recordsLinked to original sources
PubMed1991

Sensitization in vitro of human peripheral blood mononuclear cells to phenolic glycolipid 1 of Mycobacterium leprae in liposomes.

Study of primary immune responses in leprosy has been limited, since disease becomes manifest long after infection or is not detectable. To study primary immune responses, we immunized in vitro human peripheral blood mononuclear cells from unexposed individuals using phenolic glycolipid 1 (PGL-1), an important water-insoluble antigenic constituent of Mycobacterium leprae. PGL-1, encapsulated in liposomes, induced lymphoproliferation or, less frequently, suppression of lymphoproliferation in 11-day lymphocyte cultures. The primary lymphocyte responses resembled those elicited with keyhole limpet hemocyanin (KLH). HLA-DR2 expression, associated with tuberculoid leprosy, did not influence the outcome of in vitro sensitization. The association of HLA-DR2 and tuberculoid leprosy is not explained by differential ability to generate primary lymphoproliferative responses to PGL-1 or KLH. We have extended in vitro sensitization methodology to include a water-insoluble antigen in antigen-bearing liposomes. This methodology is potentially useful for studies of immunogenetics and immunopathology, and for vaccine research.

Antigens, Bacterial↗
PubMed1990

Enhanced killing of group B streptococci in vitro by penicillin and opsonophagocytosis with intravenous immunoglobulin.

Combined effects of intravenous immunoglobulin (IVIG) and antibiotics in killing bacteria are of interest with broadening clinical use of IVIG. Since the kinetics of killing by these agents differ and each may influence the outcome of the other, it is difficult to evaluate combination effects in vitro. Conditions were developed to measure killing of group B streptococci (GBS), type III strain M732, by an opsonic mixture with IVIG, fresh serum, and human polymorphonuclear leukocytes (PMNL) with or without penicillin. Bacterial killing was observed with the opsonic IVIG mixture, penicillin, and the opsonic IVIG mixture plus penicillin at 1 h. The effect of the combination was greater than the sum of the effects of two separate incubations. The enhanced killing was evident for up to 18 h. By 24 h, the killing by the combination was no greater than that by penicillin alone. A similar pattern of GBS killing was observed with cord blood PMNL, six different GBS type III strains, and pretreatment of GBS with either IVIG or penicillin. These effects suggest that the combination of IVIG and penicillin has potential for use in the treatment of neonatal GBS infections.

Humans↗
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

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

Soluble serum interleukin 2 receptor levels in leprosy patients.

Soluble interleukin 2 receptors (IL-2R) in sera of leprosy patients from Chiang Mai, Thailand, were quantified with a solid phase enzyme immunoassay using two monoclonal antibodies to the IL-2R. The IL-2R levels of untreated lepromatous, borderline lepromatous or midborderline patients and treated lepromatous and borderline lepromatous or treated borderline tuberculoid and tuberculoid patients were comparable to those of the Thai household or nonhousehold contacts; and they were significantly higher than the levels of USA control subjects. In contrast, IL-2R of untreated tuberculoid or borderline tuberculoid patients were significantly reduced. Patients with ongoing reversal reaction had very high circulating IL-2R, the levels of which correlated with fever and extent of skin lesions. Although erythema nodosum leprosum patients also had elevated IL-2R levels, they were significantly below those of patients with reversal reaction. When treated with corticosteroid, precipitous reduction of IL-2R was noted in all patients with reversal reaction but not in patients with erythema nodosum leprosum.

Enzyme-Linked Immunosorbent Assay↗
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

Leprosy associated with HLA-DR2 and DQw1 in the population of northern Thailand.

A study of the frequency of HLA-DR2 and DQw1 was performed in leprosy patients and controls in northern Thailand. HLA-DR2 was found in 100% (17/17) of patients with sporadic tuberculoid leprosy and in over 90% (30/32) of all tuberculoid leprosy patients, as compared to 62% (20/32) of controls (p = .02). These strong associations had relative risks of 21.4 for sporadic and 7.4 for all tuberculoid leprosy, and etiologic fractions of 1.0 and 0.84, respectively. There was also a statistically significant and strong association between tuberculoid leprosy and DQw1. These data add to the growing body of evidence that products of HLA class II determinants or closely linked genes may play a role in determining the clinical manifestations of M. leprae infection.

Adult↗
PubMed1979

Fatal tuberculosis in young children.

Three young children with advanced cavitary pulmonary tuberculosis died between 1974 and 1978. Two of the patients had tuberculous meningitis as well. All diagnoses were verified at autopsy; however, all tuberculin skin tests were negative. These instances emphasize the difficulty of establishing the diagnosis of tuberculosis in young children. Tuberculosis should be considered in the differential diagnosis of cavitary chest disease in young children, even those with negative tuberculin skin tests.

Age Factors↗
PubMed1978

Transfusion-related short-incubation hepatitis in hemophilic patients.

Nine episodes of a unique short-incubation form of hepatitis were observed during five years in six hemophilic children after infusion with commercial factor VIII concentrate prepared by two different manufacturers. Five patients with a single episode had no previous infusion for 14 months to 14 years. One patient with several episodes had no previous infusion for at least seven months preceding each episode. The illness was mild and self-limited. No seroconversions to cytomegalovirus, Epstein-Barr virus, toxoplasmosis, or hepatitis A virus occurred. Acute hepatitis B virus infection was also excluded. The findings suggest the presence of one or more non-A, non-B hepatitis agents associated with factor VIII concentrates.

Adolescent↗
PubMed1978

Complement-dependent serum: neuroelectric blocking activity in multiple sclerosis.

In attempting to discover a relationship between the neurologic and immunologic abnormalities in multiple sclerosis, we found a serum factor that inhibits the ventral root response in isolated, perfused frog spinal cords. This effect is correlated with disease activity. Blocking activity of the serum was lost by heating to 56 degrees C, restored by adding complement, and was found in the serum IgG fraction. There was no correlation of neuroelectric blocking activity with measles complement-fixing antibody. An antibody other than that to measles virus may thus have a role in the pathogenesis of multiple sclerosis.

Animals↗
PubMed1978

Isolation and characterization of naturally occurring subclasses of human peripheral blood T cells with regulatory functions.

By utilizing naturally occurring autoimmune antibodies from patients with juvenile rheumatoid arthritis, we have isolated and functionally characterized two unique subpopulations of T cells. JRA+ T cells, i.e., those identified by sera from these patients, react poorly in response to allogeneic cells, respond to Con A but not PHA, and do not help in the synthesis and secretion of Ig by B cells. In contrast, JRA- T cells, i.e., those not identified by sera from these patients, respond very well to allogeneic cells, proliferate well in response to PHA but not Con A, and more interestingly, can greatly enhance the secretion of Ig by B cells.

Antigens↗
PubMed1977

Antimicrobial therapy of experimental group B streptococcal infection in mice.

Group B beta-hemolytic streptococci (GB-BHS) frequently cause severe infection in newborns. Previous in vitro studies showed accelerated killing of GB-BHS by ampicillin plus gentamicin as compared with ampicillin alone. To extend the in vitro observations, mice were infected experimentally with GB-BHS and treated with gentamicin plus ampicillin or ampicillin alone. Untreated mice died within 10 to 48 h. Compared with treatment with ampicillin alone, ampicillin-and-gentamicin therapy resulted in improved survival when the antibiotics were given in established infection or as a single dose at the time of infection. Ampicillin and gentamicin accelerated the clearing of bacteremia as compared with treatment with ampicillin alone. In view of these findings, the therapy of GB-BHS infection in newborns and other patients should be reconsidered in that a combination of ampicillin or penicillin G plus gentamicin might be superior to the use of ampicillin or penicillin G alone.

Ampicillin↗