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Biomedical subjects

S Mukherjee

Publications and source records attributed to S Mukherjee.

At least 325 records · Page 18Linked to original sources
PubMed1989

Liver biopsies in the acquired immune deficiency syndrome: influence of endemic disease and drug abuse.

A retrospective review of 48 liver biopsies in 34 patients with acquired immune deficiency syndrome (AIDS) and 10 patients with AIDS-related complex (ARC) was performed at Harlem Hospital Center to assess the diagnostic yield of liver biopsies in this distinct patient population. Among the patients, 93.2% were black and 32 were males, with a mean age of 36.7 yr. Intravenous drug abuse was a risk factor for AIDS in 81.8% of patients. Liver biopsies were particularly useful in patients with fever of unclear origin, which was positively correlated with the presence of granulomas (p = 0.01). Granulomas due to mycobacteria were present in 16 (33.3%) of the biopsies. Liver biopsy proved to be clinically significant in 14 of 17 patients (82.3%) with mycobacterial disease, or 29.3% of the liver biopsies. Chronic active hepatitis was present in 12 (29.2%) of the biopsies, and in all but one was due to non-A non-B hepatitis viruses. All patients with chronic active hepatitis were intravenous drug abusers or the sexual partners of intravenous drug abusers. Liver biopsy can provide important diagnostic information in AIDS patients. The pathological findings in this series reflect the high risk of exposure to tuberculosis and hepatitis in the intravenous drug abusers in Harlem.

AIDS-Related Complex↗
PubMed1989

A comparison of the effects of 6-hydroxydopamine and reserpine on noradrenergic and peptidergic nerves in rat brown adipose tissue.

While co-existence of noradrenaline and neuropeptide-Y is, by inference, indicated in sympathetic nervous projections to rat interscapular brown adipose tissue by the fact of their coincident disappearance from the tissue following 6-hydroxydopamine treatment of the animals, reserpine treatment produced a divergent effect suggestive of possible differences either in the localisation and/or release mechanisms for noradrenaline and the peptide within the same neurons. Thus reserpine produced a depletion of noradrenaline but not of the immunohistochemically demonstrable neuropeptide-Y in the nerve plexuses of the tissue.

Adipose Tissue, Brown↗
PubMed1988

Enhancer-origin interaction in plasmid R6K involves a DNA loop mediated by initiator protein.

Initiation of DNA replication from ori beta of plasmid R6K requires the presence of the ori gamma sequence in cis. We demonstrate that binding of initiator protein to the seven strong, tandem binding sites in gamma increases binding of the protein at the very weak binding site present in ori beta by cooperativity at a distance. The gamma-beta interaction via the initiator results in a DNA loop, as revealed by the novel technique of cyclization enhancement and as confirmed by exonuclease III protection, electron microscopy, and chemical footprinting. The protein-mediated gamma-beta interaction in vitro suggests that the cooperative interaction of gamma-bound protein with the beta sequence by DNA looping is an early step in the initiation of DNA replication at the beta origin of R6K.

Allosteric Regulation↗
PubMed1988

Association of coronary calcification with obstructive disease in coronary arteries in Indian patients.

A total of 1150 consecutive patients (1052 males and 98 females; age 51.2 +/- 10.1 years) with suspected coronary artery disease (Group I) were subjected to fluoroscopy for detection of coronary artery calcification (CAC) and coronary angiography. Another group (Group II) of 120 patients (95 males and 25 females; age 51.4 +/- 9.4 years) catheterized for cardiac diseases other than coronary artery disease (CAD) were subjected to the same protocol of fluoroscopy and coronary angiography to exclude incidental CAD in view of their age. CAC was present in 240 patients (20.0%) in Group I. Of these, 200 (83.4%) had triple-vessel disease (TVD); 20 (8.3%) had double-vessel disease (DVD); 19 (7.9%) had single-vessel disease (SVD); and 37 (15.4%) patients had left main coronary disease (LMCAD). Only one of these patients had insignificant CAD considered as "normal" coronary arteries (NC). Incidence of LMCAD, TVD, DVD, SVD, and NC in patients without CAC was 4.4%, 56.3%, 18.2%, 14.0%, and 11.5%, respectively. Incidence of CAC in patients with LMCAD, TVD, DVD, SVD, and NC was 48.1%, 28.1%, 10.8%, 13.0%, and 1.0% respectively. In Group II (n = 120), 24 patients (20%) had CAD, CAC was present in 5 patients with CAD (20.9%), and in two patients without CAD (2%). CAC is relatively uncommon in Indian CAD patients. Its presence, however, indicates severe multivessel disease.

Adult↗
PubMed1988

Leishmania donovani: superoxide dismutase level in infected macrophages.

Superoxide dismutase (SOD), a metal containing enzyme is present in parasite Leishmania donovani as well as in host macrophages both resident and activated in a detectable amount, although the level is much higher in the latter case. It is observed that at any particular protein concentration, the SOD activity is highest in the case of parasite infected macrophages and lowest in the case of normal resident macrophages; the SOD activity of thioglycolate activated macrophages lies in between the two. It is also noticed that formalin-killed Leishmania donovani neither attach to macrophages nor do they increase the SOD activity of the host. Thus, the processes, e.g. attachment of the parasite to the host membrane, subsequent membrane perturbation and thus activation of membrane bound enzyme NADPH oxidase leading to respiratory burst, may be responsible for an enormous increase in the SOD level in macrophages during infection. Moreover, the chemical nature of the SOD found in infected macrophages has been investigated by using an inhibitor, e.g. NaCN, which specifically inhibits Cu-Zn SOD but not Fe-SOD. A considerable inhibition of SOD activity by NaCN in infected macrophages confirms the chemical nature of the increased SOD to be of Cu-Zn type, usually found in host. Presumably, Cu-Zn SOD or host SOD plays a protective role at the time of parasite infection although the role of parasitic SOD or some other mechanisms for the survival of the parasite within the toxic phagolysosome environment of the macrophage cannot be ruled out.

Animals↗
PubMed1988

Neuropeptides in interscapular and perirenal brown adipose tissue in the rat: a plurality of innervation.

The occurrence of neuropeptides in rat brown adipose tissue has been investigated. Immunohistochemical studies on interscapular and perirenal brown fat have demonstrated unequivocally the presence of substance-P (SP)-like, neuropeptide-Y (NPY)-like and calcitonin gene related-peptide (CGRP)-like immunoreactive elements (putative nerves) in adventitial distribution on inter- and intralobular supply arteries and in accompanying nerve bundles. At a more peripheral level, some NPY-like immunoreactive elements and a greater number of CGRP-like immunoreactive elements were observed in the parenchymal field. Somatostatin, bombesin, neurotensin, enkephalin, and vasoactive-intestinal-polypeptide immunoreactivities were not detected. No differences in neuropeptide distribution were noted between interscapular and perirenal brown fat. There is a degree of coincident distribution of SP, NPY and CGRP with that of noradrenergic nervous elements as visualized by condensation histochemistry. Since after 6-hydroxydopamine treatment not all the nerve terminals in rat brown adipose tissue are stigmatized (earlier report), the present results have been discussed in the light of a possible pluralism in innervation of brown adipose tissue.

Adipose Tissue, Brown↗
PubMed1988

Identification and characterization of a Mg2+-dependent and an independent Ca+2-ATPase in microsomal membranes of rat testis.

Rat testicular microsomal membrane fraction contains both Mg+2-dependent and Mg+2-independent Ca+2-ATPase activity. The latter activity is about two times higher than the former. Calcium ion required for maximum activation of Mg+2-independent Ca+2-ATPase in 3.0 mM, whereas for the dependent one it is 2.5 mM. Both the enzymes are resistant to cold shock upto seven days. Histidine and imidazole buffers are found to be the most suitable for dependent and independent enzyme activities, respectively. The pH optima for dependent one is 7.5, whereas for the independent one it is 8.5. Temperature optima for the former is 37 degrees C and for latter one it is 40 degrees C. Among all the nucleotides tested, ATP is found to be the best substrate for both the enzymes. The optimum concentration of ATP for dependent and independent enzyme activities are 3.0 mM and 1.5 mM respectively. Divalent metal ions like Zn+2, Ba+2 and Mn+2 have been found to inhibit Mg+2-dependent Ca+2-ATPase activity whereas Mg+2-independent Ca+2-ATPase activity is inhibited by the divalent ions except zinc which is found to stimulate the enzyme activity. Both the enzymes are inhibited by vanadate, EDTA and EGTA. I50, for vanadate is 0.05 and 0.125 mM for dependent and independent activities, respectively. Sulfhydryl groups modifying agents e.g., NEM, DTNB and chlorpromazine are found to affect the enzyme activities in different ways. Thus NEM and chlorpromazine are found to inhibit and DTNB stimulate the enzyme activities in both the cases.

Animals↗
PubMed1988

Leishmania donovani: role of microviscosity of macrophage membrane in the process of parasite attachment and internalization.

Host macrophage infection by the parasite Leishmania donovani is heterogeneous, but it is not clear which factors are responsible for parasite recognition within the macrophages. One possible factor may be the alteration of the microviscosity of the macrophage membrane. This in turn may affect receptor expression and hence parasite infection. In this paper we describe alteration of the lipid composition and hence the microviscosity of the macrophage membrane in a controlled manner using liposome fusion technique. At a higher macrophage membrane microviscosity a larger number of parasites have been found to adhere to the macrophage surface. However, the proportion of parasites finally internalized when compared to parasites adhering to macrophages is inversely correlated with the artificially altered macrophage membrane microviscosity. The process of endocytosis has been examined in both native and lipid modified macrophages in the presence of several sugar antagonists. The results indicate (i) glucose and mannose are specifically involved in the binding process, and (ii) the microviscosity has a key role in controlling the macrophage parasite interaction. The results obtained so far support a model of endocytosis where expression of the receptor is a critical initial process dependent on the microviscosity of the membrane.

Animals↗
PubMed1988

Neuropeptide and noradrenaline distributions in rat interscapular brown fat and in its intact and obstructed nerves of supply.

Following demonstration of noradrenergic and peptidergic nerves in rat interscapular brown adipose tissue, neuronal courses were investigated with reference to both the segmentally derived nerve traversing the fat pad and to paravascular projections, employing respectively, sucrose potassium glyoxylic acid and indirect immunofluorescence methodologies. Following ligation of the segmental nerve before its pad entry and distal to the pad, accumulations of noradrenaline, neuropeptide-Y, calcitonin gene-related peptide and substance P were observed immediately proximal to the ligature in all nerve components (T1-5). Two to three days after unilateral nerve resection (proximal to the pad), with or without simultaneous contralateral padectomy, there was, in some sections of the denervated pads either total absence of, or a very sparse distribution of both noradrenergic and peptidergic labelled nerves, thus suggesting minimal paravascular projection of these nerves and a major projection via the defineable segmental nerve route.

Adipose Tissue, Brown↗
PubMed1988

Detection of DNA looping due to simultaneous interaction of a DNA-binding protein with two spatially separated binding sites on DNA.

We describe different and relatively rapid biochemical techniques to detect protein-mediated DNA looping. These techniques, based on enhancement of DNA knotting and that of ligase-catalyzed cyclization, were used to show that the replication initiator protein of plasmid R6K can bring together two intramolecular gamma origin of replication sequences located as far apart as 2 kilobases. The site-site interaction causes looping out of the intervening DNA sequence as visualized by electron microscopy. Because the autoregulatory sequence of the initiator cistron also binds initiator protein, we investigated whether the gamma origin-bound protein can participate in autoregulation by interaction of the two sites through a protein bridge. We discovered that the two sites do not interact in vitro at their natural locations when on opposite faces of the double helix. Moving the two sites to the same face of the double helix by introducing a half turn into the intervening sequence allows protein-mediated site-site interaction to occur.

DNA Replication↗
PubMed1988

Schizophrenic symptoms and deterioration. Relation to computed tomographic findings.

Thirty-two patients with a research diagnosis of chronic schizophrenia were studied using structured clinical scales for premorbid adjustment, clinical symptomatology, and social deterioration. By computed axial tomography (CAT), ventricle-brain ratio (VBR) and cortical atrophy were assessed. The relation between the clinical variables and CAT findings was assessed using linear correlation. CAT-based subgroups were compared using univariate analysis of variance. Previous findings of ventricular enlargement and cortical atrophy in some schizophrenics were replicated. Premorbid asociality and social deterioration were found to have a modest, positive relation with CAT findings but formal thought disorder had a negative relation to ventricle size. There was no relation between the negative symptoms and CAT measures. Within the CAT-positive group the presence of cortical atrophy appeared to be associated with a more severe illness compared with those with ventricular enlargement but the sample sizes were too small to obtain any significant differences.

Adult↗
PubMed1988

Inhibition of bacterial colonization by antimicrobial agents incorporated into dental resins.

The antimicrobial activity of several chemical agents was determined by incorporating these agents into dentine adhesive resin and following the colonization of Streptococcus mutans on the surfaces of the resin and culture vessel, as well as in the surrounding medium, by optical density measurements. It was found that sodium fluoride and dodecylamine, an organic amine, exhibited excellent antimicrobial properties. These chemicals not only inhibited bacterial growth completely but also seemed to reduce the adhesion of the bacteria to the resin surface. A silver compound, protargin, was mildly effective in inhibiting growth of S. mutans. Copper oxide and chelating acids such as vanillic acid, syringic acid, and ethylenediamine-n, n' diacetic acid (EDDA) were not effective as antimicrobial agents against S. mutans.

Amines↗
PubMed1988

Effect of aerosol challenge with sensitising antigen on the permeability of the surface of the rat trachea in life.

A rat model of immediate pulmonary hypersensitivity was used to investigate the permeability changes in the tracheal epithelium produced by aerosol challenge with antigen. The rats were sensitised by the intraperitoneal injection of antigen (dinitrophenyl (DNP19) ovalbumin). Sensitised and control animals were then challenged for 60 minutes with an aerosol of the same antigen, which also contained the electron dense pore marker lanthanum. Histological examination and x ray probe microanalysis showed a greater intercellular concentration of lanthanum in the tracheal epithelium in sensitised than in control animals. The results show that in sensitised rats increased intercellular penetrance of antigen can occur after antigen challenge.

Animals↗
PubMed1988

The interaction of chloroquine with transport ATPase and acetylcholine esterase in microsomal membranes of rat in vitro and in vivo.

Chloroquine, an antimalarial drug has been found to inhibit Na+, K+-ATPase activity in vitro in the microsomal membranes of rat brain on time, temperature and concentration dependent manner. There have been stimulation of Na+,K+-ATPase, Ca+2-ATPase and acetylcholine esterase activities in vivo studies at lower concentration of drug or shorter period of treatment with the drug, whereas higher concentrations or longer periods of treatment lead to inhibition in the microsomal membranes of different organs.

Acetylcholinesterase↗