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Biomedical subjects

A Mookerjee

Publications and source records attributed to A Mookerjee.

At least 19 recordsLinked to original sources
PubMed1999

Immunosuppression in hamsters with progressive visceral leishmaniasis: an evaluation of the role of nitric oxide toward impairment of the lymphoproliferative response.

The progressive visceral infection caused in golden hamsters by Leishmania donovani amastigotes led to gradual impairment of the proliferative response of their splenic (SPMC) or peripheral blood (PBMC) mononuclear cells to in vitro stimulation with leishmanial antigen, with mitogen (concanavalin A), and even with a combination of phorbol myristate acetate (PMA) and ionomycin (Io). Removal of macrophage-like adherent cells from SPMC or PBMC of infected animals, however, almost completely restored their proliferative response to PMA + Io, thus ruling out the possibility of any intrinsic defect in the signal-transduction pathways of lymphocyte activation and proliferation. Subsequent studies demonstrated that the generation of soluble mediators such as nitric oxide by these adherent cells is responsible, albeit partially, for the down-regulation of the lymphoproliferative response in hamsters with visceral leishmaniasis.

Animals↗
PubMed1999

Therapeutic and prophylactic uses of protein A in the control of Leishmania donovani infection in experimental animals.

The role of the immunomodulator Protein A (PA) (from Staphylococcus aureus, Cowan I strain) in the control of leishmanial infection was studied in experimental animals. Treatment of Leishmania donovani infected hamsters with PA led to a moderate level of reduction of parasite load in their spleen (68%) and liver (46%). However, combination therapy of PA with the antileishmanial drug stibanate induced a more marked reduction of the spleen (88%) and liver (85%) parasitemia compared to that induced by PA or drug treatment alone. Similar results were also obtained with L. donovani infected BALB/c mice as the combination therapy of PA and stibanate led to a significant reduction (84%) of liver parasite load in comparison to that induced by PA (38%) or drug (61%) treatment alone. Apart from its therapeutic use, PA could also be used as a prophylactic agent in the control of leishmanial infection. Thus, treatment of hamsters with PA before leishmanial challenge significantly reduced their organ parasite load (by 59-78%) compared to that observed in infected controls without prior PA treatment. The antileishmanial effect of PA was likely to be mediated through the activation of macrophages leading to an enhancement of their phagocytic as well as leishmaniacidal activities. Subsequent studies demonstrated that PA treatment led to an increased production of nitric oxide by macrophages which could primarily be responsible for their enhanced parasite killing ability.

Adjuvants, Immunologic↗
PubMed1990

An insight into the structure of DNA through melting studies.

Helix-coil transition of calf thymus (CT) DNA in 0.1 M NaCl was observed under different environmental conditions for studying structural and conformational changes, if any. Pre-exposure of the DNA to different types of radiations - UV and gamma-brought different degrees of change (lowering) in the melting temperature (Tm). Interaction of drugs (daunomycin and actinomycin-D) increased the Tm inducing structural stability. There was 50% more destabilisation in case of polynucleotide-drug complex as compared to DNA-drug complex exposed to UV radiation. Thermodynamic studies on DNA in D2O (0.1 M NaCl prepared in D2O) were carried out and compared with the corresponding results in H2O. Presence of D2O increased the stability of the DNA structure. Structural and conformational aspects have been discussed in the light of the results obtained.

Animals↗
PubMed1982

Spectrophotometric observations on the changes in the Y-peak of actinomycin D complexed to DNA on gamma-irradiation.

An understanding of the pi-pi * transitions of the Y-peak of the DNA bound to actinomycin D, in the presence and absence of gamma-irradiation has been attempted. It was seen that in the bound DNA the presence of the Y-peak, without irradiation was mainly due to the pi-pi * transitions associated with the DNA bases. The Y-peak was found to be more sensitive to the binding of the drug than the X-peak. After gamma-irradiation the Y-peak characteristics of the complexed DNA were different from those of the X-peak. From these studies it has been concluded that the electronic transitions (pi-pi *) of the DNA, in the far U.V., can be divided into three distinct groups: (a) Electronic transitions which are only seen at the Y-peak, (b) Transitions common both to the X and Y-peaks, and (c) Transitions which are only seen at the X-peak. This explains the difference in the behaviour of the Y- and X-peaks of the DNA due to the binding of Act.D and gamma-irradiation.

Animals↗
PubMed1982

Chronic potassium depletion and sensitivity to tubocurarine.

The effect of low potassium diets with and without deoxycorticosterone (DOCA), furosemide, chlorothiazide, or ethacrynic acid on sensitivity of isolated guinea pig lumbrical nerve-muscle preparations to d-tubocurarine was examined. The ED50 of d-tubocurarine was found to fall as the potassium level was lowered by dietary restriction. Addition of DOCA or furosemide was without effect while chlorothiazide reduced and ethacrynic acid enhanced the effect of diet alone. Acute restoration of potassium levels of 5.9 mM reversed considerably, but not completely, the effect of chronic depletion. Thus, a patient suffering from chronic potassium depletion would be expected to require a decreased dose of d-tubocurarine, and although acute replacement of potassium preoperatively would tend to return the dose requirement toward normal, such reversal might not be complete.

Animals↗
PubMed1981

RNA synthesis and degradation during preferential inhibition of protein synthesis by cobalt chloride in Escherichia coli K-12.

It has been observed that growth of Escherichia coli cells are inhibited when treated with cobalt chloride (300 microM). It has also been shown that CoCl2 preferentially inhibits translation without inhibiting the process of transcription (1, 2, 8). We report here, that during treatment of E. coli cells with CoCl2, both messenger RNA and stable RNA synthesis is slowed down about 2.5 folds. The rate of degradation of mRNA also decreases and both chemical and functional half-life of mRNA increases about 2.5 folds in Co-treated cells. This clearly shows that the process of transcription is also affected while translation is preferentially inhibited during CoCl2 treatment.

Cobalt↗