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Biomedical subjects

V Kumar

Publications and source records attributed to V Kumar.

At least 127 records · Page 7Linked to original sources
PubMed1989

IgA pemphigus foliaceus. Report of two cases and a review of the literature.

The cases of two patients with vesiculobullous lesions were diagnosed clinically and histopathologically as pemphigus foliaceus; unexpectedly, both revealed intercellular IgA, but not IgG, in the upper epidermis by direct immunofluorescence. Such histologic and immunofluorescence findings have been reported in eight other cases. In our cases no circulating IgA or IgG intercellular antibodies could be detected; in four of eight other reported cases IgA antibodies showed intercellular staining like that of pemphigus antibodies. Subcorneal acantholytic lesions occurred in both our cases; of the other cases reported, five had essentially identical histopathologic findings. The clinical and histopathologic features of pemphigus, as well as the recent findings of circulating IgA intercellular antibodies alone or with IgG antibodies, appear to place this disease into the spectrum of pemphigus. The 10 IgA pemphigus cases reported to date fall into one of two groups, the IgA pemphigus foliaceus (including our two cases) and IgA pemphigus of the intraepidermal neutrophilic type, which seems to be less common.

Adult↗
PubMed1989

A unilateral mesenchymal disorder of the head.

A hitherto undescribed group of lesions consisting of cystic bony lesions, exostosis, fibromatous lesion, unilateral tonsillar hypertrophy, epidermoid cyst (cholesteatoma) and hyperplasia of the mandible confined to the left side of the face is reported. The case may represent a variant of the Proteus syndrome.

Adult↗
PubMed1989

Suppression of prolactin gene expression in GH cells correlates with site-specific DNA methylation.

Prolactin- (PRL) producing and nonproducing subclones of the GH line of (rat) pituitary tumor cells have been compared to elucidate the regulatory mechanisms of PRL gene expression. Particular emphasis was placed on delineating the molecular basis of the suppressed state of the PRL gene in the prolactin-nonproducing (PRL-) GH subclone (GH(1)2C1). We examined six methylatable cytosine residues (5, -CCGG- and 1, -GCGC-) within the 30-kb region of the PRL gene in these subclones. This analysis revealed that -CCGG-sequences of the transcribed region, and specifically, one in the fourth exon of the PRL gene, were heavily methylated in the PRL-, GH(1)2C1 cells. Furthermore, the inhibition of PRL gene expression in GH(1)2C1 was reversed by short-term treatment of the cells with a sublethal concentration of azacytidine (AzaC), an inhibitor of DNA methylation. The reversion of PRL gene expression by AzaC was correlated with the concurrent demethylation of the same -CCGG- sequences in the transcribed region of PRL gene. An inverse correlation between PRL gene expression and the level of methylation of the internal -C- residues in the specific -CCGG-sequence of the transcribed region of the PRL gene was demonstrated. The DNase I sensitivity of these regions of the PRL gene in PRL+, PRL-, and AzaC-treated cells was also consistent with an inverse relationship between methylation state, a higher order of structural modification, and gene expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Pan natural killer cell monoclonal antibodies and their relationship to the NK1.1 antigen.

The study of natural killer (NK) has been difficult because they account for a small percentage of peripheral blood and splenic lymphocytes and the paucity of NK specific antigens that have been identified. We have isolated pure populations of C57BL/6 (H-2b) NK cells using the IgG2b monoclonal antibody PK136 (anti-NK1.1). These NK1.1+ cells were used to immunize 129/J (H-2b) mice, and in this report, we describe three new NK specific monoclonal antibodies (SW3A4(IgM), SW4B12(IgG1), and SW2B4(IgG2b] and their relationship to the known murine NK antigen NK1.1. We have further characterized the NK1.1 antigen as a 39 kd molecule which is coded for by a gene which appears to map to chromosome 6.

Animals↗
PubMed1989

Estimation of plasma tacrine concentrations using an in vitro cholinesterase inhibition assay.

THA (9-amino, 1,2,3,4-tetrahydroacridine; tacrine) is currently under study as a cholinesterase (ChE) inhibitor in Alzheimer disease. In this study, a sensitive radiometric assay for THA inhibition of human plasma ChE, suitable for detection of effects of orally administered drug, is described. The assay is sensitive in a range of 4-50 ng/ml plasma. Reversibility of the inhibition permits distinguishing of drug effects on ChE from changes in amount of enzyme synthesized during treatment.

Administration, Oral↗
PubMed1989

Pemphigoid, pemphigus and desmoplakin as antigenic markers of differentiation in normal and tumorigenic mouse keratinocyte lines.

The expression of differentiation stages in a murine epidermal cell transformation model has been investigated as a basis for studies of chemically-induced differentiation. Antibodies in sera of patients with the autoimmune diseases bullous pemphigoid and pemphigus vulgaris exhibit specific reactivity to antigenic determinants of basal and spinous cells, respectively, in sections of mouse and human epidermis. In addition, spinous cells in epidermis are reactive with a mouse monoclonal antibody to desmoplakin, a desmosomal component immunologically distinct from pemphigus. These antibodies were used to identify and attempt to quantify keratinocyte subpopulations in culture based on differentiation stage. Epidermal cell lines were cultured under conditions which favour proliferation (0.02 to 0.04 mM extracellular Ca2+, i.e. low Ca2+ conditions) or differentiation (0.1 mM to 1.4 mM Ca2+), as previously shown using primary cultures of mouse keratinocytes. Two independently-derived normal keratinocyte lines demonstrated Ca2(+)-dependent reactivity with pemphigoid and pemphigus antiserum, like that which has been observed in primary cultures. Furthermore, a Ca2+ and time-dependent reactivity with the three antisera was also observed in a papilloma cell line (derived from one of the normal cell lines after treatment in vitro with 7,12-dimethylbenz[alpha]anthracene). Papilloma cells cultured under conditions of low extracellular Ca2+ were comprised of three subpopulations: cells reactive only with pemphigoid anti-serum, cells reactive only with desmoplakin antibody. However, like the normal cell lines, papilloma cells underwent a transition to predominantly a spinous cell population (i.e. reactive with pemphigus and desmoplakin antibody) in response to extracellular Ca2+. A slower loss of pemphigoid antibody reactivity was noted in papilloma cells, consistent with an abnormal regulation of differentiation. The attempt to characterize these dynamic transitions from basal to spinous cell subpopulations in culture was considered to be prerequisite for the use of the model to investigate differentiation-inducing agents in carcinoma therapy.

Animals↗
PubMed1989

CSF choline and acetylcholinesterase in early-onset vs. late-onset Alzheimer's disease patients.

Cerebrospinal fluid acetylcholinesterase (AChE) activity levels and choline (Ch) levels were studied in 52 dementia of Alzheimer type (DAT) patients and 20 age-matched controls. The AChE activity was significantly lower and Ch levels were significantly higher in DAT patients than the age-matched controls. There was no significant difference in AChE activity and Ch levels between early-onset (less than or equal to 65 years) patients and late-onset (greater than 65 years) patients. However, the AChE activity was significantly lower in early-onset patients compared with their age-matched controls but no difference was observed in late-onset patients compared with their age-matched controls. None of the biological measures (AChE, Ch) were significantly correlated with the degree of cognitive impairment, duration of the illness or the sex of these patients.

Acetylcholinesterase↗
PubMed1989

Comparison of the characteristics of infiltrates in skin and nerve granulomas of leprosy.

The characteristics of infiltrates in the dermal and neural granulomas from the same leprosy patients were compared by preparing a single cell suspension. Skin and nerve biopsies from 10 patients, 5 with tuberculoid and 5 with lepromatous leprosy were analysed. The granulomas contained lymphocytes and macrophages. Lymphocytes were the predominant infiltrating cells in the tuberculoid dermal and neural granulomas. A high proportion of lymphocytes in both the skin and nerve granulomas in these cases were activated T cells as they formed rosettes with sheep erythrocytes and expressed HLA-DR antigens. In contrast, lepromatous dermal and neural granulomas contained very few of these lymphocytes. Dermal and neural granulomas from both the types of leprosy contained mature macrophages as they were esterase positive, did not exhibit peroxidase activity and expressed HLA-DR antigens. These macrophages did not possess C3 surface receptors either. These findings suggest that the infiltrates in the skin and nerve granulomas of a given type of leprosy have similar characteristics.

Brachial Plexus↗
PubMed1989

Management of birth asphyxia by traditional birth attendants.

Birth asphyxia is an important cause of perinatal mortality, especially in developing countries. A study in India has shown that traditional birth attendants can recognize the condition but mostly cannot deal with it. The authors suggest that this deficiency could be overcome if suitable training were given.

Asphyxia Neonatorum↗
PubMed1989

Eurytrema coelomaticum infection in bovines in an abattoir in south Brazil.

Two and a half per cent of the 200 bovines examined in an abattoir in South Brazil had pancreatic gross lesions associated with Eurytrema coelomaticum infection. The lesions were mainly subacute periductular pancreatitis and the accompanying alterations in the adjacent parenchyma. Relevant literature is reviewed and compared with the results of the present study.

Animals↗
PubMed1989

Clinical pharmacology of tetrahydroaminoacridine: a possible therapeutic agent Alzheimer's disease.

Tetrahydroaminoacridine (THA) was administered to a small number of patients with Alzheimer's disease. A minority of patients received the drug for longer than one week. Only one investigator [Summers et al. 1986] has reported dramatic palliative effects from the administration of THA. All investigators other than Summers reported side effects, especially troublesome is the frequent appearance of indications of hepatotoxicity. The efficacy and safety of THA are unknown. There is evidence that THA may have complex modes of action in addition to the inhibition of cholinesterases. There is a need for careful clinical assessment of THA and for further investigation of possible mechanisms of action.

Alzheimer Disease↗