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Biomedical subjects

A Sengupta

Publications and source records attributed to A Sengupta.

At least 109 records · Page 6Linked to original sources
PubMed1984

Phosphate repression of phage protein synthesis during infection by choleraphage phi 149.

A synthetic medium for choleraphage phi 149 growth, in which the concentration of phosphate ions plays a significant role, has been defined. Upon infection, choleraphage phi 149 DNA binds to the cell membrane at three to four sites. The host macromolecular syntheses are shut off by 10 min after infection and the synthesis of phage-specific DNA is detectable after 20 min of infection. The phage utilizes primarily the host DNA degradation products for its own DNA synthesis. When added during the first 20 min of infection both nalidixic acid and novobiocin inhibit phage growth. The effects of these antibiotics are not pronounced when added late during infection. Pulse labeling of ultraviolet-irradiated infected cells at different times during infection has allowed identification of about 50 phage-specific proteins of which 19 are structural proteins. These proteins appear during the infection cycle in two distinct phases, early and late. When infection is carried out in high-phosphate medium, none of the late proteins is synthesized. Eleven of the 26 early proteins detected are DNA-binding proteins.

Bacteriophages↗
PubMed1984

Comparative studies on calotropins DI and DII from the latex of Calotropis gigantea.

Autodigestion of two cysteine proteinases, calotropins DI and DII isolated from the latex of Calotropis gigantea, has been studied at pH 7.5 and 37 degrees C in the presence of an activating agent. Calotropin DI is more susceptible to autodigestion than calotropin DII. During autodigestion no interconversion of one calotropin to another has occurred, as verified by polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate. Immunologically, both calotropins are closely related, but they differ from papain and ficin. Both calotropins have blocked N-terminal amino acid residues. Their C-terminal amino acid sequences, determined by treatment with carboxypeptidase Y, are -(Pro, Ala)-Ala-Val-Tyr for calotropin DI and -(Ala, Val)-Ala-Pro-Tyr for calotropin DII. The tryptic peptide maps of their reduced and S-carboxymethylated derivatives suggest that both calotropins share a high proportion of common regions in their amino acid sequences. Calotropins DI and DII are two distinct proteinases, and they do not appear to be produced by autodigestion of a single precursor. Although they are inert to the common synthetic substrates of papain and ficin, their specificities toward oxidized insulin B chain are comparable to those of papain and ficin.

Amino Acids↗
PubMed1983

Duration of meiosis and spermiogenesis in the dog.

The duration of meiosis and spermiogenesis was studied in the dog by following the kinetics of [3H]thymidine-labeled canine spermatocytes autoradiographically. Leptotene appears to last for at least 4.20 days, zygotene for less than a day, and pachytene for about 15.50 days. The transition from diplotene to metaphase II is extremely rapid and requires approximately a day. The duration of spermiogenesis is at least 19.60 days. Both meiosis and spermiogenesis are completed by 42.15 days.

Animals↗
PubMed1980

Management of fusiform ascending aortic aneurysms.

Thirteen patients had elective surgical treatment of fusiform ascending aortic aneurysms at Strong Memorial and Rochester General Hospitals from 1970 to 1978. There were 8 men and 5 women ranging in age from 51 to 78 years (mean, 61 years). Nine patients underwent composite tube graft and aortic valve replacement, 3 had aortic valve replacement plus supracoronary tube grafts, and 1 had aortic valve replacement plus aneurysmorrhaphy. Coronary reimplantation alone or combined with saphenous vein bypasses was fashioned in 10 patients. Potassium cardioplegia was considered a useful adjunct in 6 patients. Two early deaths accounted for an operative mortality of 15.4%. There were 3 late deaths. Eight patients are alive and well 2 to 109 months after operation.

Aged↗
PubMed1980

Investigation of glycopyrrolate as a premedicant drug.

The clinical efficacy of glycopyrrolate, a synthetic anticholinergic drug, for premedication was compared in a double-blind study with that of atropine or hyoscine in patients anaesthetized with diethyl ether. The antisialogogue actions of the three drugs were similar. Glycopyrrolate produced less tachycardia, pyrexia and blurred vision than atropine, and its sedative effect was less than that of hyoscine.

Adult↗
PubMed1977

Propoxyphene overdosage: a study of cases involving analgesic preparations containing dextropropoxyphene.

Propoxyphene and paracetamol concentrations have been determined in blood, urine, liver blood and stomach contents from 17 post mortem cases in which Distalgesic (a propoxyphene and paracetamol compound preparation) was involved. Five patients admitted to hospital with suspected Distalgesic poisoning have also been investigated. In most cases the propoxyphene concentrations, but not the paracetamol concentrations, exceeded the minimum lethal levels reported. On the basis of our results it appears that of the constituents of Distalgesic, propoxyphene has a far more immediate and dangerous effect than paracetamol.

Acetaminophen↗