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Biomedical subjects

D K Banerjee

Publications and source records attributed to D K Banerjee.

At least 73 records · Page 4Linked to original sources
PubMed1985

Susceptibility of Mycobacterium leprae to the bactericidal activity of mouse peritoneal macrophages and to hydrogen peroxide.

Macrophages from athymic nude mice were infected in vitro with Mycobacterium leprae to study the intracellular fate of this organism. Using the proportional bactericidal test, we have shown that the viability of M. leprae declines rapidly within these macrophages, although results of clearance experiments demonstrate that live and killed organisms are cleared at comparable rates. We have also shown that M. leprae is susceptible to the bactericidal effects of hydrogen peroxide and we suggest that hydrogen peroxide generated by macrophages is responsible for the killing of intracellular M. leprae.

Animals↗
PubMed1985

Hydrogen peroxide and superoxide production by peripheral blood monocytes in leprosy.

Susceptibility to infection with Mycobacterium leprae, the causative organism of leprosy, is the result of a defect in cell-mediated immunity (CMI). The co-operation of macrophages and T lymphocytes is known to be essential for competent CMI response. In this study we have examined peripheral blood monocytes from a range of leprosy patients in an attempt to identify a possible defect in macrophage function. The ability of these cells to produce hydrogen peroxide and superoxide, two bactericidal metabolites of the monocyte/macrophage, has been measured. Monocytes from leprosy patients were found to be capable of producing normal amounts of hydrogen peroxide and superoxide, and no differences in production were found between tuberculoid, lepromatous and control monocytes. These results suggest that macrophages in leprosy are competent, and that probably a T lymphocyte defect contributes to susceptibility to this disease.

Adolescent↗
PubMed1984

Cyclic AMP mediates beta-adrenergic-induced increases in N-linked protein glycosylation in rat parotid acinar cells.

beta-Adrenergic stimulation of rat parotid cells by isoprenaline (isoproterenol) results in 2-3-fold increases in [3H]mannose incorporation into N-linked oligosaccharides. This occurs without perceptible lag and is linear with time for 60 min after agonist addition. Concomitantly, isoprenaline markedly increases cellular cyclic AMP. Examination of individual proteins by sodium dodecyl sulphate/polyacrylamide-gradient-gel electrophoresis reveals that glycosylation changes are primarily associated with four secretory proteins, of approx. Mr 17000, 32000, 38000 and 220000. Beta-Adrenoreceptor activation additionally elicits a slight increase in parotid protein synthesis. The greatest increase in [14C]leucine incorporation is that into another secretory protein (Mr approx. 24000). Exposure of cells to dibutyryl cyclic AMP yields results comparable with those after isoprenaline treatment. Forskolin, which increases parotid-cell cyclic AMP, also causes similar effects. Conversely, dibutyryl cyclic GMP shows no such response. The data are consistent with the notion that beta-adrenergic stimulation of N-linked protein glycosylation in rat parotid cells is mediated by cyclic AMP.

Animals↗
PubMed1984

Isolated chromaffin cells from adrenal medulla contain primarily monoamine oxidase B.

Cultured chromaffin cells from bovine adrenal medulla were found to contain primarily the B form of monoamine oxidase. This monoamine oxidase B enzyme was somewhat distinct from B enzymes from other sources, in that noradrenaline was a much poorer substrate than serotonin. Nonetheless, studies with selective inhibitors of the A form (clorgyline) and the B form [(-)-deprenyl] confirmed that chromaffin cell monoamine oxidase was the B form. The observation that chromaffin cell monoamine oxidase has poor affinity for catecholamines is consistent with physiological needs that require the cell to synthesize and store large amounts of catecholamines.

Adrenal Medulla↗
PubMed1984

Attempts at cultivation of Mycobacterium leprae in macrophages from susceptible animal hosts.

Macrophages from nude mice, nude rats, and armadillos were cultured in vitro and examined for their ability to support Mycobacterium leprae. No significant growth of this organism were observed after over 200 days of culture. No significant benefit was derived from modifying culture conditions or from variations in the source of macrophages or the source of M. leprae.

Animals↗
PubMed1983

Genetic evidence that action of cAMP-dependent protein kinase is not an obligatory step for antiviral and antiproliferative effects of human interferon in Chinese hamster ovary cells.

Several Chinese hamster ovary (CHO) cell mutants with altered cAMP-dependent protein kinases were utilized to study the possible involvement of this enzyme in mediating interferon effects in cultured cells. Human fibroblast interferon had a pronounced protective effect for CHO cells against encephalomyocarditis virus (EMCV). This protective effect was also observed in cAMP-resistant CHO mutants with protein kinase defects, although to a slightly lesser extent. EMCV, however, which grows well in wild-type CHO cells, grew poorly in the cAMP-resistant CHO mutants even in the absence of interferon, suggesting that cAMP-dependent protein kinase is involved in the normal growth of this virus. The growth inhibitory and morphological effects of human fibroblast interferon on CHO cells as well as the induction of 2',5'-oligoA synthetase and the level of RNase F activity (which is constitutive in CHO cells) were very similar in wild-type and mutant CHO cells. It is concluded from these studies that cAMP-dependent protein kinase may have a facilitating role in antiviral activity of interferon, but does not have an obligatory role in mediating either the antiviral or antiproliferative effects of interferon in CHO cells.

2',5'-Oligoadenylate Synthetase↗
PubMed1983

Thermodynamic profiles for alcohol dehydrogenase action in free solution.

Stopped-flow equipment was used to study the kinetics of the reaction between nicotinamide adenine dinucleotide (NAD) and ethanol, catalyzed by yeast alcohol dehydrogenase. By measuring rates over a range of concentrations of NAD and ethanol and of temperatures, thermodynamic profiles were obtained for the reaction, which occurs by an ordered ternary complex mechanism with NAD adding first. There are significant negative entropies of activation and negative entropy changes for the addition of NAD and of ethanol; the breakdown of the ternary complex is, however, accompanied by a positive entropy of activation. The results are consistent with structural constraints associated with the binding of the substrates, these restraints being to some extent removed when the ternary complex undergoes reaction. The system follows a similar pattern to that found with three different varieties of lactate dehydrogenase.

Alcohol Oxidoreductases↗
PubMed1983

Interferon increases IgE binding to basophils.

One of the pivotal manifestations of immediate type hypersensitivity is mediator release from a variety of mediator cells, e.g., mast cells and basophils. The essential step of this process is the binding of immunoglobulin E (IgE) to the surface of these cells. In the present studies we examined the influence of human interferon (HuIFN) on the binding of IgE to human leukocytes (basophils). The results of these studies indicate that pre-treatment of leukocytes (basophils) with different types of IFN leads to a pronounced increase in binding of IgE to these cells. These data support the hypothesis concerning a pathogenetic role of IFN in the development of allergy of the immediate type hypersensitivity.

Basophils↗
PubMed1982

Bronchial hyperreactivity associated with tracheal gangliosides.

Gangliosides, which are membrane constituents of animal cells, may be altered under various conditions that cause change in metabolism. In this study, gangliosides from tracheal and lung tissues were extracted and measured as a function of bronchial hyperreactivity in a guinea pig model of bronchial asthma. When plotted logarithmically, the data showed that tracheal gangliosides decreased with an increase in airway reactivity index, suggesting a linear relation between them. Differential analysis of tracheal gangliosides in the acute stage of bronchial hyperreactivity indicates accumulation of polysialogangliosides. These data support the hypothesis that tracheal gangliosides are intimately involved in the development of bronchial asthma.

Animals↗
PubMed1982

Interferon-mediated inhibition of adenylate cyclase in mouse cells.

Adenylate cyclase activity was measured in mouse cell plasma membrane after 30 units/ml of interferon (IFN) treatment. The basal and Gpp(NH)p stimulated enzyme activity in LB cell was inhibited by 20%-40% throughout the time course of treatment (30 min to 18 h). The reduced enzyme activity was not associated with enhanced breakdown of cAMP, but was related to alteration in the catalytic component of the enzyme. Moreover, there was no change in the affinity for guanine-nucleotide regulatory unit and 1 X 10(-7) M Gpp(NH)p was required to obtain half-maximal activation with either type of membrane. Interferon action on adenylate cyclase was biphasic, at 10 u/ml it was stimulatory and between 30 and 1000 u/ml it inhibited the enzyme activity to a great extent; but IFN did not exert its effect directly on the enzyme. The reduction in enzyme activity was comparable to a reduction in the intracellular level of cAMP in most of the interferon-sensitive cell lines studied. We propose, therefore, that the inhibitory effect on adenylate cyclase is related to a step in the development of antiviral activity.

1-Methyl-3-isobutylxanthine↗
PubMed1982

The emergency evacuation of a geriatrics hospital in Toxteth.

The evacuation of a 102-bed geriatrics hospital in the middle of the night and from the centre of a riot in Toxteth, Liverpool, is described, together with its effect on the patients involved. No increase in the mortality rate occurred during the six weeks following the evacuation, but a significant increase in morbidity was found. Specific recommendations are made for action to be taken should other city centre geriatrics hospitals need to be evacuated in similar circumstances.

Aged↗
PubMed1981

dl-17 beta-hydroxy-8 alpha-androst-4-en-3-one (8-isotestosterone).

The molecular conformation of dl-8-isotestosterone has been determined crystallographically. Crystals of the title compound belong to the space group P21/c with a = 11.449(4), b = 10.962(4), c = 25.860(5) A, beta = 100.95(4)o, with two molecules in the asymmetric unit. The structure has been refined to a final R value of 0.052 for 2227 reflections. Unlike testosterone, which is a flat molecule, its 8-isomer has a folded conformation. The conformations of the ring-B in the two crystallographically independent molecules (A and B) corresponded to the twist form and differ significantly from one another.

Chemical Phenomena↗
PubMed1980

Interferon treatment inhibits glycosylation of a viral protein.

Earlier, we reported a 30-200-fold reduction in the yield of infectious vesicular stomatitis virus (VSV) released from L cells treated with 10-30 reference units ml-1 of interferon (IFN); however, in these cultures virus particle production, as measured by VSV particle-associated viral RNA, virus nucleocapsid protein and viral transcriptase, was inhibited less than 10-fold. There was biochemical and morphological evidence of a significant reduction in glycoprotein (G) and membrane protein (M) of VSV particles released from IFN-treated cells. We compare here the effects of tunicamycin (TM) and IFN in L cells. Treatment with TM or IFN reduced the production of infectious VSV particles, decreased the amount of G and M proteins in VSV released from treated cells, and inhibited an early step in the formation of asparagine-linked oligosaccharide chains, the incorporation by membrane preparations from treated cells of N-acetylglucosamine into glycolipids with the properties of dolichol derivatives.

Dolichol Phosphates↗
PubMed1980

Status of ascorbic acid in iron deficiency anaemia and thalassaemia.

The status of ascorbic acid was studied at the levels of platelet and leucocyte in 32 cases of iron deficiency anaemia, 35 cases of thalassaemia and 18 normal subjects. It was found that in iron deficiency anaemia, platelet ascorbic acid was significantly higher than normal values indicating tissue excess and came down sharply after treatment with iron. In thalassaemia, associated presumably with iron overload, ascorbic acid status of platelets was definitely lower than normal indicating tissue deficiency. Leucocytic level of ascorbic acid was not as good an index of ascorbic acid status as the platelet level.

Anemia, Hypochromic↗
PubMed1979

Changes in T and B blood lymphocytes after splenectomy.

The blood lymphocytes of 37 splenectomised patients were analysed by means of T and B lymphocyte surface markers. Sixteen patients had had a splenectomy for non-haematological and 21 for haematological reasons. The results show that 15 had normal numbers of T and B cells; decreased T cells were found in two patients, raised B cells in seven, raised T and B cells in eight, and raised T cells in five patients. Increased numbers of 'null' cells were observed in some patients, especially in those with raised B cells. Follow-up studies indicate that raised levels of T and B cells can be established by one to three months post-splenectomy and may persist, although in some patients the cells fall to normal levels. The lymphocyte proliferative response to phytohaemagglutinin and Concanavalin A in vitro was normal in eight out of nine patients with raised T cells and was depressed in one patient, possibly due to an intrinsic cell defect.

Adolescent↗