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Biomedical subjects

R S Barnetson

Publications and source records attributed to R S Barnetson.

107 records · Page 6Linked to original sources
PubMed1976

Clinical response of dermatitis herpetiformis skin lesions to a gluten-free diet.

Patients with dermatitis herpetiformis have been studied prospectively for 2 years to assess the effect of a gluten-free diet (GFD) on control of the skin lesions. Daily requirements for oral medication with sulphapyridine or dapsone were reduced by GFD treatment and if complete clinical remission of the skin disease occurred, it was maintained while the diet was strictly observed. However, complete remission did not occur significantly more often in GFD-treated patients than in patients taking a normal diet. Many of the latter group exhibited variation in their drug dose requirements during the period of study. GFD treatment seems desirable for the majority of patients with dermatitis herpetiformis, not only to correct the intestinal abnormality but also to minimize the dose of drugs necessary to control the skin lesions.

Adolescent↗
PubMed1976

Immune complexes and complement hypercatabolism in patients with leprosy.

The occurrence of immune complexes in the serum and the level of the C3 breakdown product C3d in the plasma from patients with leprosy were studied by quantitative methods and the results were compared in various forms of the disease. These studies were performed on sixty-two samples from twenty-six patients. The serum 125I-C1q binding activity was found to be increased by more than 2 s.d., as compared to the normal values, in most of the sera from patients with erythema nodosum leprosum (ENL) (80%) and uncomplicated lepromatous leprosy (82%), but also in the sera from patients with tuberculoid leprosy (58%). In vitro studies suggested that immune complexes involving mycobacterial antigens were present in leprosy sera. An increased C3d level (greater than 2s.d.) was also found in most of the plasma from patients with ENL (70%), but rarely in the plasma from patients with uncomplicated lepromatous leprosy (18%) and never in tuberculoid leprosy patients' plasma. The absence of a significant correlation between the 125I-C1q binding activity and the C3d level in leprosy patients may suggest that extravascular immune complexes are involved in the complement activation occurring in ENL. The quantitation of C3d in plasma may be of some practical interest in the early diagnosis of ENL complications of leprosy.

Adult↗
PubMed1976

Plasma factors in delayed-type hypersensitivity. Augmentation of lymphocyte responses in borderline leprosy reactions.

The phytohaemagglutinin-induced responses of lymphocytes were found to be inhibited by plasma from patients with leprosy when compared with their responses in pooled serum from healthy donors. When patients developed reversal reactions, the initial inhibitory effect of their plasma was replaced by an augmentary effect on the responses to phytohaemagglutinin. The period of augmentation coincided with that of the reversal reaction in patients with borderline tuberculoid leprosy, but was delayed in patients with borderline lepromatous leprosy. The plasma from each leprosy patient was also observed to have the same effect on lymphocytes from unrelated individuals, showing that the inhibition and augmentation were due to factors in the plasma and not to a change in lymphocyte receptors. It is possible that the normal stable state of leprosy results from the presence of factors in plasma which act as a control mechanism, and that delayed hypersensitivity reactions may be caused by a breakdown of this control.

Adolescent↗
PubMed1976

Lymphocyte transformation test in leprosy; correlation of the response with inflammation of lesions.

Lymphocyte transformation tests (LTT) using 'whole washed" and 'sonicated" preparations of Mycobacterium leprae (M. leprae) as antigen were studied in eighty-one patients with borderline leprosy. The results were correlated with the histological and the clinical pictures. There was a good correlation with the histological spectrum, LTT responses generally being higher in the borderline tuberculoid leprosy patients and lower in the borderline lepromatous. However, considerable variation was noted in each group of the borderline leprosy spectrum, and it was found that this was due in part to the degree of inflammation in the skin. Thus those with 'inflamed" skin lesions had higher responses than those with 'silent" lesions, and even those with borderline lepromatous leprosy with inflamed lesions had higher responses than those with borderline tuberculoid leprosy whose lesions were silent. Those who had reversal reactions, where inflammation is very marked, had very high LTT responses which fell with treatment of the reaction with steroids. It thus appears that the LTT in leprosy is influenced by the occurrence of hypersensitivity reactions as well as by the patient's ability to resist bacillary multiplication.

Adolescent↗
PubMed1975

Antigenic heterogeneity in patients with reactions in borderline leprosy.

Fifteen patients with borderline leprosy who developed "reversal" reactions were studied from the inception of treatment. Thirteen showed an appreciable increase in lymphocyte transformation (LT) when preparations of Mycobacterium leprae were used as antigen. The LT responses to either "whole" or "sonicated" preparations of the bacillus in these 15 patients and in nine others also in reaction correlated with the clinical presentation. Those with skin disease predominating in the reaction showed an appreciable increase in LT when whole M leprae was used as antigen. Those with nerve disease predominating showed an increase with sonicated M leprae. In those with both skin and nerve disease there was an increase with both antigen preparations. The ratios of the LT test results (whole to sonicated M leprae) showed highly significant differences between the three groups.

Adolescent↗
PubMedDate not supplied

Spontaneous regression of human melanoma/nonmelanoma skin cancer: association with infiltrating CD4+ T cells.

Spontaneous regression occurs in some human malignant melanomas and basal cell carcinomas (BCCs). We have compared the cellular infiltrate in regressing and nonregressing tumors in order to analyze the mechanism by which regression occurs. Regressing primary melanomas and BCCs were infiltrated with a larger number of CD4+, but not CD8+, T lymphocytes than were seen in nonregressing tumors. The number of interleukin 2 receptor-positive (early activation marker) but not transferrin receptor-positive (intermediate activation marker) T cells was increased, indicating that the infiltrating T cells were activated. Large numbers of Langerhans cells, macrophages, and other class II major histocompatibility complex (MHC)-expressing cells were present but were not increased in the regressing tumors. There were no detectable B lymphocytes, and the regressing tumor cells displayed levels of HLA-DR expression similar to those of the nonregressing tumors. Comparison of squamous cell carcinoma (SCCs) with keratoacanthomas (KAs), which are likely to be a spontaneously regressing form of SCC, also showed increased infiltration of activated CD4+, but not CD8+, T cells within the KA. A murine ultraviolet (UV)-induced squamous tumor that spontaneously regresses when transplanted into immunocompetent syngeneic mice was also infiltrated with increased numbers of activated CD4+, but not CD8+, T cells prior to and during rejection. These results indicate that spontaneous regression of human skin tumors is likely to be immunologically mediated, and that CD4+ T lymphocytes seem to mediate this regression.

Animals↗
PubMedDate not supplied

Subclinical infection with Mycobacterium leprae--a problem for leprosy control strategies.

Tests for the serodiagnosis of leprosy, including those based on phenolic glycolipid-I (PGL-I), have shown poor specificity for leprosy in studies of endemic communities, despite initially promising results in studies of selected patients. During a 5 years follow-up study of a hyperendemic community in Papua New Guinea, a marked reduction in numbers of seropositive children and an increase in age of those seropositive followed introduction of multi-drug therapy. This was accompanied by a reduced case detection rate and a shift to paucibacillary disease in new cases, consistent with a reduction in transmission. Only a minority of persistently seropositive persons developed leprosy. These observations suggest that subclinical infection with Mycobacterium leprae is common in endemic communities and that PGL-I seropositivity is a marker of subclinical infection, with poor specificity for overt disease. Detection of subclinical infection may confound control strategies which use screening tests to identify asymptomatic highly infectious cases for earlier therapy.

Adolescent↗