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R Smith

Publications and source records attributed to R Smith.

At least 847 records · Page 47Linked to original sources
PubMed1992

Effects of ethanol and its fluorinated analogues on the calcium ATPase of sarcoplasmic reticulum.

The effects of ethanol, monofluoro- and trifluoroethanol on the hydrolysis of ATP and coupled Ca2+ translocation by sarcoplasmic reticulum Ca(2+)-ATPase (EC 3.6.1.38) were measured. All three alcohols had parallel effects on the enzyme activities at concentrations up to 200 mM, suggesting a similar mechanism of action. 19F nuclear magnetic resonance spectroscopy was used to investigate their site of action in the purified enzyme.

Animals↗
PubMed1992

Proviral insertions near cyclin D1 in mouse lymphomas: a parallel for BCL1 translocations in human B-cell neoplasms.

By isolating genomic DNA clones that encompass the mouse Cyl-1 (cyclin D1) locus, we have identified a putative CpG island close to the 5' end of the gene. Pulsed-field gel electrophoresis with probes derived from either the 5' or 3' side of the CpG island established physical linkage to two independent markers on mouse chromosome 7, in a region that is syntenic with human chromosome 11q13. On the 3' side, Cyl-1 is approximately 75 kb from Hst-1 and Int-2, although there is an additional CpG island in the intervening DNA, while on the 5' side, Cyl-1 is less than 300 kb from Fis-1, an integration site for Friend murine leukaemia virus. As there is no intervening CpG island, proviral insertions at Fis-1 could influence the expression of Cyl-1 and we describe two virally induced tumours in which this appears to be the case. The data suggest that proviral insertions near Cyl-1 in mouse lymphomas are functionally equivalent to the BCL1 translocations that activate cyclin D1 expression in human B-cell malignancies.

Animals↗
PubMed1992

Ultrasonographic and radiologic evaluation of patients after laparoscopic cholecystectomy.

The first 30 patients scheduled to undergo laparoscopic cholecystectomy at the Kingston General Hospital, Kingston, Ont., were studied by abdominal ultrasonography and abdominal roentgenography 24 hours after the procedure. The ultrasonogram appeared normal in 21 of the 29 patients in whom laparoscopic cholecystectomy was successful. In six of the eight patients with an abnormal ultrasonogram a tiny collection of fluid was identified in the gallbladder fossa; in two patients retained intraperitoneal stones were identified (one of these patients also had a small fluid loculus); and one patient had a small amount of free fluid in Morrison's pouch. This last patient was subsequently found to have a retained common-bile-duct stone, which required endoscopic removal. Plain films showed moderate to large amounts of retained gas intraperitoneally in only three patients. Colonic distension was recorded in 23 of the 28 patients studied, suggesting a partial colonic ileus. Residual pneumoperitoneum and colonic distension did not correlate with any untoward clinical findings. This study demonstrates that most patients have complete reabsorption of their pneumoperitoneum within 24 hours of laparoscopic cholecystectomy and that small amounts of fluid in the gallbladder fossa and mild to moderate colonic distension are not significant in terms of operative complications.

Abdomen↗
PubMed1991

A Plasmodium falciparum exo-antigen alters erythrocyte membrane deformability.

Here we describe a reduced membrane deformability of human erythrocytes when aspirated into 0.6 microns diameter in polycarbonate sieves, after exposure of uninfected cells to spent parasite-culture supernatant. This, taken in concert with a previous observation that intra-erythrocytic development of the parasite P. falciparum decreases host localised membrane deformability, may indicate a biological role for such parasite-induced changes in the rheological properties of the erythrocyte.

Animals↗
PubMed1991

A comparison of enalapril with hydralazine-isosorbide dinitrate in the treatment of chronic congestive heart failure.

BACKGROUND: To define better the efficacy of vasodilator therapy in the treatment of chronic congestive heart failure, we compared the effects of hydralazine and isosorbide dinitrate with those of enalapril in 804 men receiving digoxin and diuretic therapy for heart failure. The patients were randomly assigned in a double-blind manner to receive 20 mg of enalapril daily or 300 mg of hydralazine plus 160 mg of isosorbide dinitrate daily. The latter regimen was identical to that used with a similar patient population in the effective-treatment arm of our previous Vasodilator-Heart Failure Trial. RESULTS: Mortality after two years was significantly lower in the enalapril arm (18 percent) than in the hydralazine-isosorbide dinitrate arm (25 percent) (P = 0.016; reduction in mortality, 28.0 percent), and overall mortality tended to be lower (P = 0.08). The lower mortality in the enalapril arm was attributable to a reduction in the incidence of sudden death, and this beneficial effect was more prominent in patients with less severe symptoms (New York Heart Association class I or II). In contrast, body oxygen consumption at peak exercise was increased only by hydralazine-isosorbide dinitrate treatment (P less than 0.05), and left ventricular ejection fraction, which increased with both regimens during the 2 years after randomization, increased more (P less than 0.05) during the first 13 weeks in the hydralazine-isosorbide dinitrate group. CONCLUSIONS: The similar two-year mortality in the hydralazine-isosorbide dinitrate arms in our previous Vasodilator-Heart Failure Trial (26 percent) and in the present trial (25 percent), as compared with that in the placebo arm in the previous trial, (34 percent) and the further survival benefit with enalapril in the present trial (18 percent) strengthen the conclusion that vasodilator therapy should be included in the standard treatment for heart failure. The different effects of the two regimens (enalapril and hydralazine-isosorbide dinitrate) on mortality and physiologic end points suggest that the profile of effects might be enhanced if the regimens were used in combination.

Adolescent↗
PubMed1991

What now for IPPNW?

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International Cooperation↗
PubMed1991

Interleukin 7 receptor engagement stimulates tyrosine phosphorylation, inositol phospholipid turnover, proliferation, and selective differentiation to the CD4 lineage by human fetal thymocytes.

The purposes of this study were to elucidate the effects of recombinant human interleukin 7 (rhIL-7) on proliferation as well as differentiation of human fetal thymocytes and to analyze the biochemical nature of the IL-7 receptor-linked transmembrane signal. In the absence of costimulants, rhIL-7 stimulated the in vitro proliferation and colony formation of CD4+CD8+ double-positive immature fetal thymocytes. Furthermore, rhIL-7 promoted partial differentiation of immature thymocytes with a selective advantage for the development of CD4+CD8- single-positive thymocytes. Our observations suggest that IL-7 likely has an important regulatory role during the earliest stages of human T-cell ontogeny. Stimulation of fetal thymocytes with rhIL-7 resulted in enhanced tyrosine phosphorylation of three distinct phosphoproteins with molecular masses of 72, 98, 123, and 190 kDa and induced a rapid and biphasic increase in the production of inositol 1,4,5-trisphosphate, which was inhibitable by the tyrosine protein kinase inhibitor genistein. Thus, the transmembrane signal triggered by engagement of the IL-7 receptor is intimately linked to a functional tyrosine protein kinase pathway and stimulates the inositol phospholipid turnover and proliferation, as well as selective differentiation to the CD4 lineage, by human fetal thymocytes.

Antibodies, Monoclonal↗
PubMed1991

The BMA in agony.

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Government↗