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S Hasnain

Publications and source records attributed to S Hasnain.

43 records · Page 3Linked to original sources
PubMed1975

Temperature related alterations in the acidic alanine-rich "A" protein from the 50S ribosomal particle of the extreme halophile, Halobacterium cutirubrum.

50-S ribosomal subunits from the extreme halophilic bacterium, Halobacterium cutirubrum, contain an alanine-rich acidic "A" protein which resembles the L7--L12 multimer (Kaltschmidt and Wittmann, 1970) found in the 50-S ribosomal subunit of Escherichia coli cells. The protein contains 24 mole % alanine and is devoid of histidine, tryptophan and cysteine. Unlike E. coli which has two forms of the "A" protein distinguished solely by the acetylation state of the serine amino terminus. H. cutirubrum 50-S subunits contain only one unsubstituted form of the "A" protein in vivo. However, during purification of ribosomes from cells grown between 25 and 37 degrees C the latter "A" protein undergoes rapid, specific, in vitro enzymatic alteration at its carboxy-terminal end. When the halophile is grown in the temperature range of 40 to 42 degrees C the cleaving enzyme is not active and only one form of the "A" protein is found on the ribosomes.

Alanine↗
PubMed1975

Ion effects on protein-nucleic acid interactions: the disassembly of the 50-S ribosomal subunit from the halophilic bacterium, Halobacterium cutirubrum.

The 50-S ribosomal subunits from the extreme halophilic bacterium, Halo-bacterium cutirubrum, stable structurally and functionally in concentrated salt solutions were subjected to ionic environments depleted in either K+ or Mg2+ or both. Under these conditions specific classes of proteins are released from the subunit along with the 5 S RNA. Two-dimensional electrophoretic analysis of the resultant split protein fractions indicate some mutually exclusive effects of specific ions on the binding of specific proteins to the 23 S RNA as well as on the retention of 5 S RNA within the ribosomal macrostructure.

Bacterial Proteins↗
PubMed1975

Purification of multiple forms of the soluble 17alpha-hydroxy steroid dehydrogenase or rabbit liver.

Eight distinct forms of the soluble 17alpha-hydroxy steroid dehydrogenase of rabbit liver were resolved by DEAE-cellulose chromatography and isoelectric focusing. Five of these enzymes were homogeneous as judged by polyacrylamide-gel electrophoresis. Substrate-specificity studies carried out with oestradiol-17alpha and oestradiol-17alpha 3-glucuronide revealed a variation in activity toward these substrates among the different purified enzyme forms. Three forms of the 17alpha-hydroxy steroid dehydrogenase exhibited equal activity toward both oestrogen substrates, whereas three forms of the enzyme displayed a greater activity toward the glucuronide derivative of oestradiol-17alpha. One enzyme in particular is essentially specific for oestradiol-17alpha 3-glucuronide, its activity toward oestradiol-17alpha being only one-thirtieth that observed with the 3-glucuronide derivative.

Animals↗
PubMedDate not supplied

Conversion to cardiopulmonary bypass in off-pump coronary artery bypass grafting: its effect on outcome.

The surgical outcome of patients requiring conversion to cardiopulmonary bypass (CPB) during myocardial revascularization using the less invasive surgical approach (LISA) was assessed. The LISA was recently introduced as a technique for complete myocardial revascularization without CPB. It combines avoidance of CPB with the versatility of a median sternotomy for access to all coronary vessels. We have previously demonstrated reduced risk-adjusted mortality and complications in off-CPB coronary artery bypass grafting (CABG) using LISA compared to standard myocardial revascularization. From January to December 1997, 1210 patients underwent isolated CABG at our institution. Of these patients, 832 (63%) were scheduled as on-CPB cases and 378 (37%) as off-CPB. Of the off-CPB patients, 48 were converted to CPB. Team A surgeons used LISA as their primary strategy for CABG whereas team B surgeons used off-CPB CABG in selected patients. Conversions were divided in three classes: Class I patients were converted when the surgeon considered complete revascularization impossible off-CPB; Class II patients were converted due to hemodynamic instability during the procedure; and Class III patients were converted due to graft malfunction, determined by flow measurements or clinical evidence. There were four deaths. All had perioperative infarctions and required intra-aortic balloon pump (IABP). Conversion to CPB occurred in up to 25% of patients scheduled for off-CPB CABG. When off-CPB cases are done using the comprehensive LISA technique and modern technology, conversion rates may be reduced to 11%. Conversion is in general well tolerated except when it is instituted for graft malfunction combined with hemodynamic instability or collapse.

Adult↗
PubMedDate not supplied

Limited access left thoracotomy for reoperative coronary artery disease: on or off pump.

Between 1971 and 1988 left thoracotomy was performed on pump for selected reoperations. Since 1993, 92 patients were operated on with a limited approach and an increased number of cases were done off pump (70 patients). The purpose of this paper is to describe the transition of our operative techniques from on pump to off pump for reoperative coronary patients. From 1995 to 1999, 22 patients (Group 1) were operated on pump and 70 patients (Group II) off pump; 86 of 92 (93.5%) had reoperations. The demographic data were similar in these two groups regarding age, gender, ejection fraction, and total number of grafts performed. In this study 92 patients had a crude mortality of 4.3%. Limited access thoracotomy provides safer reoperation than previously (1971-1988) with an improved on or off pump (4.5% vs. 4.3%) mortality, compared to the on pump mortality of 10% between 1971-1988. Off-pump operations are performed with increasing frequency and with the same risk and less postoperative complications.

Aged↗