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Biomedical subjects

M R Rao

Publications and source records attributed to M R Rao.

At least 163 records · Page 9Linked to original sources
PubMed1983

Purification of a retinol binding protein from the hen-oviduct cytosol and its immunological cross-reactivity with those from the nucleus.

Cellular retinol-binding protein was purified from the cytosol of the oviducts of laying hens by ammonium sulphate fractionation and chromatography on Sephadex G-75 and DEAE-Sephadex A-50 columns. Analysis of the purified retinol-binding protein on 10% SDS-polyacrylamide gel revealed the presence of a doublet representing very similar molecular sizes. Antiserum was prepared against the purified cellular retinol-binding protein, and on the basis of (a) immunodiffusion test and (b) immunoneutralization of 3H-labelled retinol-cellular retinol-binding protein complex on a column of Sephadex G-75, the antiserum appeared to be specific. The antiserum showed cross-reactivity with the nucleosol and a 0.4 M NaCl extract of the chromatin of the oviduct nuclei, while it did not react with the major egg-white proteins such as ovalbumin, conalbumin and ovomucoid.

Animals↗
PubMed1982

Localization of testis-variant histones in rat testis chromatin.

Nucleosome core particles and oligonucleosomes were isolated by digesting rat testis nuclei with micrococcal nuclease to 20% acid-solubility, followed by fractionation of the digest on a Bio-Gel A-5m column. The core particles thus isolated were characterized on the basis of their DNA length of 151 +/- 5 base-pairs and sedimentation coefficient of 11.4S. Analysis of the acid-soluble proteins of the core particles indicated that histones TH2B and X2 are constituents of the core particles, in addition to the somatic histones H2A, H2B, H3 and H4. The acid-soluble proteins of the oligonucleosomes comprised all the histones, including both the somatic (H1, H2A, H2B, H3, H4 and X2) and the testis-specific ones (TH1 and TH2B). It was also observed that histones TH1 and H1 are absent from the core particles and were readily extracted from the chromatin by 0.6 M-NaCl, which indicated that both of them are bound to the linker DNA.

Animals↗
PubMed1982

Effect of prolactin inhibition by bromocriptine on testicular metabolism in the adult rat.

Administration of bromocriptine resulted in a decrease of testicular tissue somatic index, total, structural and soluble protein concentrations. The catabolic phase of carbohydrate metabolism was enhanced. Consequently, the required metabolites for increased citric acid cycle activity were provided by increased glycolytic activity. The pre-requisite metabolites needed for spermatogenic processes were accumulated in the testis, due to their non-utilization. The results obtained suggest a specific influence of prolactin inhibition on testicular metabolism in the adult rat.

Adenosine Triphosphatases↗
PubMed1981

Moderate-dose methotrexate in head and neck cancer.

200 mg/m2 methotrexate given intravenously in a running drip for 6 h has been used as an initial adjuvant therapy in 38 patients with advanced head and neck cancer. The response rate is as high as 80%, with 21% achieving complete remission. Histologically, specimens were tumor free in 3 patients. Toxicity in 38 patients included leukopenia (4), mucositis (6) and diarrhea (1). This particular dose of methotrexate appears to be safe and usually does not need leucovorin rescue. Also, when given as initial treatment, it is effective in reduction of tumor bulk. A prolonged randomized trial is essential to determine its role in improving long-term survival.

Adult↗
PubMed1980

A comparative study of the early effects of phenobarbital and 3-methylcholanthrene on the synthesis and transport of ribonucleic acid in rat liver.

At 2-3 h after phenobaribtal administration, the drug has no effect on nucleoplasmic RNA synthesis and decreases nucleolar RNA synthesis. However, at this time there is an increase in the labelling of cytoplasmic poly(A)-containing RNA, even though there is decreased labelling of total polyribosomal RNA. The decrease in labelling of nucleolar and total polyribosomal RNA owing to phenobarbital is a transient phenomenon. Under similar conditions, 3-methylcholanthrene has no effect on nucleolar RNA synthesis, but leads to an increase in synthesis of nucleoplasmic and cytoplasmic poly(A)-containing RNA. Cytosol isolated from phenobarbital-treated, but not from 3-methyl-cholanthrene-treated, animals facilitates an enhanced transport of RNA from nuclei. At the time points investigated, 3-methylcholanthrene or its metabolite shows a 10-15-fold higher concentration in the chromatin than that of phenobarbital or its metabolite. It is suggested that the primary effect of phenobarbital is at the cytoplasmic level, promoting the transport of RNA from the nuclei, which can act as a trigger for enhanced transcription at later periods. 3-Methylcholanthrene or its metabolite directly binds to the chromatin and evokes a selective transcriptional response.

Animals↗
PubMed1979

Isolation and characterization of binding proteins for retinol from the cytosol, nucleosol and chromatin of the oviduct magnum of laying hens.

Protein fractions that bind retinol were isolated from the cytosol, nucleosol and chromatin of the oviduct magnum of laying hens. The proteins isolated from the three sources showed similar elution profiles on chromatography through Sephadex G-75 and G-50 columns, and comparable mobility during electrophoresis on sodium dodecyl sulphate/polyacrylamide gels. Their molecular weights were calculated to be around 14500. When oviducts from vitamin A-depleted and vitamin A-repleted immature chicks given oestrogen injections for 6 consecutive days were incubated with [3H]retinyl acetate, uptake of the radioactivity in the nuclei of the vitamin A-depleted tissue was severalfold higher than that in the nuclei from the vitamin A-repleted tissue.

Animals↗