Search PubMed⌕ Search

Biomedical subjects

D Wallach

Publications and source records attributed to D Wallach.

At least 235 records · Page 13Linked to original sources
PubMed1982

Imbalances in T cell subpopulations in lepromatous leprosy.

Circulating T cells, T helper, and T suppressor cells were investigated in 24 lepromatous patients, using murine hybridoma-derived monoclonal antibodies OKT 3, OKT 4, and OKT 8. Six bacillary lepromatous patients without recent eNL were studied; in this group, suppressor cells were increased and helper cells diminished, resulting in a decrease in the helper/suppressor (H/S) ratio. Nine bacteriologically negative lepromatous patients without recent ENL were studied. T cell subsets distribution was normal, although some T cell functions were affected. It was further shown that in non-ENL patients, the diminution of the H/S ratio is correlated with the Bacteriologic Index (BI). Although bacillary, ENL patients exhibit a completely different T cell pattern than non-reactional patients. In these patients, there was a significant diminution of circulating suppressor cells, and an increase in T cell functions. These abnormalities were transient. Our results confirm the importance of suppressor cells in lepromatous leprosy, and suggest that imbalance between helper and suppressor cells may play a role in the pathogenesis of ENL reactions.

Adolescent↗
PubMed1981

Assay of an interferon-induced enzyme in white blood cells as a diagnostic aid in viral diseases.

Interferon is part of the system of defence against viral infections and has important cell-regulatory and immunoregulatory functions. It is, however, not always possible to quantify circulating interferon in patients. An assay has been developed to measure an interferon-induced enzyme in white blood cells. The activity of this enzyme is constant in healthy subjects but increases by 2-10 times in 85% of patients with acute viral infections. It is also enhanced in autoimmune diseases and in virus-related malignancies and neurological disorders. The enzyme level was not raised in bacterial infections or non-infectious diseases studied. This simple and rapid biochemical assay of the interferon system could be used for diagnosis and evaluation of many diseases.

2',5'-Oligoadenylate Synthetase↗
PubMed1981

Monitoring of interferon therapy by assay of (2'--5') oligo-isoadenylate synthetase in human peripheral white blood cells.

With the increasing number of patients undergoing experimental interferon therapy, there is a need for a method for monitoring how the patients respond to the drug. Interferon induces in cells exposed to it the accumulation of several enzymes, among them the (2'-5') oligo-A synthetase. A simple method previously developed was used to measure this enzyme in extracts of a small number of peripheral white blood cells. In 60 healthy volunteers, the enzyme level in the mononuclear cell fraction was found to be relatively high and constant. Daily intramuscular injections of 1--2 x 10(6) units leukocyte type interferon (IFN-alpha) increased the enzyme level 7--8 fold in mononuclear cells and in granulocytes. The enzyme stayed high until IFN injections were stopped. Patients with defective response to IFN were identified. We propose that this method be used for continuous monitoring of the patient's response whenever interferon therapy is undertaken.

2',5'-Oligoadenylate Synthetase↗
PubMed1981

An immunofluorescence study of the skin in diabetes mellitus.

The clinically normal skin of the lower back of 30 patients with diabetes mellitus was examined, using the direct immunofluorescence technique. No deposit of immunoglobulins or complement (C3) could be demonstrated, while other authors have previously reported lupus-like deposits in diabetes mellitus. As other discrepant studies of skin immunofluorescence have been published, it is suggested that the standards of the various immunopathology laboratories are different. This may explain why the actual value of the lupus band test remains controversial.

Adult↗
PubMed1981

Studies on T cell subsets and functions in leprosy.

T cell subsets and T cell functions were explored in 31 leprosy patients with the following methods: determination of the percentages of the different T cell subpopulations defined by monoclonal antibodies directed at total T cells, helper T cells and suppressor/cytotoxic T cells; measurement of the in vitro proliferative responses to mitogens; study of the concanavalin A-induced suppressive activity, assessed on MLC; measurement of delayed-type hypersensitivity by skin testing. The confrontation between immunological lepromatous patients without type-2 reaction (erythema nodosum leprosum), (2) lepromatous patients without ENL (erythema nodosum leprosum), (2) lepromatous patients was recent ENL and (3) tuberculoid patients. Unexpectedly, groups 1 and 3, although differing strongly in their clinical status and their sensitivity to lepromin (absent in group 1 and strong in group 3), showed a similar immunological profile with a normal percentage of T cells and a normal distribution of T cells among the major T cell subset contrasting with a moderate decrease of proliferative responses to mitogens and impaired delayed-type hypersensitivity reactions. Concanavalin A-induced suppressive activity was type-2 reaction) strongly differed from both other groups, showing striking abnormalities other groups, showing striking abnormalities of the repartition of the T cell subsets, with increased percentages of helper T cells and decreased percentages of suppressor T cells, and elevated proliferative responses to mitogens. Concanavalin A-induced suppressive activity was reduced in most patients of this group. It is suggested that this imbalance between T cell subsets contributes to the occurrence of ENL reactions in lepromatous patients.

Adolescent↗
PubMed1981

[The specificity of the lupus band test. Personal findings and literature data (author's transl)].

The lupus band test is usually considered as a valuable aid for the diagnosis of lupus erythematous. Involved skin shows positive results in about 900 p. 100 of cases of discoid LE and systemic LE. However, the specificity of this test has been challenged by reports of positive immunofluorescent findings in other cutaneous diseases, like rosacea, in non-cutaneous diseases, and in healthy individuals. Discrepant data from the literature prompted us to report our own experience : direct immunofluorescent examination of skin biopsies was performed in 550 patients from a dermatologic department. Concerning diseased skin, a dermal-epidermal band was observed only in 18 cases of lupus erythematosus, in 4 cases of lepromatous leprosy, in one case of vasculitis, one case of prurigo, and one case of dermatomyositis. Concerning healthy skin, a band was seen only in 8 cases of systemic lupus erythematosus. These results confirm other reports establishing the specificity of the lupus band test.

Diagnosis, Differential↗
PubMed1980

An interferon-induced cellular enzyme is incorporated into virions.

The mechanisms by which interferon inhibits viral growth are only partially understood. Several enzymatic activities increase in cells shortly after treatment with interferon. One of these enzymes, oligo-isoadenylate synthetase, synthesizes (2'-5') isoadenylate oligomers which strongly stimulate the activity of a cellular ribonuclease, RNase F (ref. 7). Interferon also significantly increases the activity of a protein kinase which phosphorylates the initiation factor eIF-2 and can inhibit in vitro protein synthesis. Such interferon-induced enzymes, which affect RNA and protein metabolism, might be responsible for many of its effects on viruses. Indeed, inhibition of viral protein and RNA synthesis appears to have a major role in the antiviral state. We have now investigated possible interactions of the two enzymes with viral constituents during the course of infection and found that in two different membrane-coated RNA viruses, vesicular stomatitis virus (VSV) and Moloney murine leukaemia virus (M-MuLV), there is an accumulation of the 2'-5') oligo-isoadenylate synthetase (E) in the virions. Most of the enzyme is bound to the virion ribonucleoprotein core. The incorporation of E into the virions suggests a direct involvement of the enzyme in regulation of virus functions.

Adenine Nucleotides↗
PubMed1980

Self-association of chicken gizzard filamin and heavy merofilamin.

Filamin is a high molecular weight (subunit Mr 250 000) actin-binding protein isolated from smooth muscle. The protein forms a gel when mixed with solutions of F-actin. A proteolytic fragment of filamin, heavy merofilamin (subunit Mr 240 000), generated by the action of Ca2+-activated protease binds to actin but does not produce gelation. We have studied the self-association properties of filamin and heavy merofilamin by direct examination in the electron microscope and by equilibrium sedimentation distribution studies in the ultracentrifuge. Filamin self-associates reversibly to form dimers; the free energy of dimerization is approximately 7 kcal/mol. Further association to form tetramer and multimer appears to be irreversible. Warming of filamin solutions accelerates aggregation. Heavy merofilamin does not appear to self-associate but is entirely monomeric. These studies suggest that filamin produces gelation of F-actin by binding to actin and then self-associating to cross-link actin filaments into a gel.

Animals↗