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S Jenkins

Publications and source records attributed to S Jenkins.

152 records · Page 9Linked to original sources
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Comparison of intermittent warm and cold blood perfusion during hypothermic myocardial preservation on functional and metabolic recovery.

Numerous techniques are used to maintain intraoperative heart viability. The studies presented here evaluated heart function and metabolism after various periods of preservation up to 4 hours with intermittent warm and cold blood perfusion. Using a heterotopic heart model cooled to 10 degrees C and maintained for 1, 2, 3, and 4 hours, various preservation techniques were compared. Changes in myocardial metabolism were determined from substrate uptakes and biopsy samples of the left ventricular muscle for high-energy phosphates. Preservation techniques included: (1) sustained hypothermia, (2) 1 or 2 hours of sustained warm blood perfusion with fibrillation, (3) intermittent cold blood perfusion during 2, 3, and 4 hours of preservation, (4) intermittent warm blood perfusion during 2, 3, and 4 hours of preservation and (5) a control group (no preservation). Normothermic fibrillation had no effect on postpreservation functional or metabolic parameters. Sustained hypothermia reduced functional recovery proportional to the length of ischemia. The cold intermittent procedures maintained function and metabolism better than sustained hypothermia, while warm intermittent preservation maintained function and metabolism at control levels throughout the recovery period for all preservation techniques. Changes in ATP mirrored the functional changes. Creatine phosphate (CP) was markedly reduced during heart isolation and preservation and exceeded the control by 100% during reperfusion. For operative procedures of 2 hours or less, functional and metabolic recovery was not affected by the various preservation methods applied. Warm intermittent perfusion during hypothermic preservation offered the best protection for the myocardium. The warming cycles during hypothermia may provide some degree of preconditioning and protect the myocardium during reperfusion.

Animals↗
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Comparison of two commercially available chlorhexidine mouthrinses: I. Staining and antimicrobial effects in vitro.

Several commercially produced chlorhexidine rinses are now available. These formulations vary in concentration and recommended regimens of use. One formulation, a 0.1% chlorhexidine rinse, anecdotally has been reported to not produce the characteristic dental staining. The aim of this study was to compare the 0.1% formulation with a 0.2% commercially produced chlorhexidine rinse for staining and antimicrobial effects in vitro. Tea staining of tooth and acrylic specimens exposed to the two rinses at various dilutions was measured over a 5-day period. Minimum inhibitory dilutions of each product against standard test bacteria were determined by agar dilution. The 0.1% product produced no staining of specimens greater than that noted with controls. At equivalent concentrations, the 0.2% product produced heavy staining of specimens. The antimicrobial effect of the two products was similar but the overall profile for the 0.1% preparation suggested activity derived from ingredients other than chlorhexidine. The results suggest that the chlorhexidine in the 0.1% rinse was partly or completely inactivated and, although staining may not occur in vivo, the formulation would have a much reduced antiplaque action.

Chlorhexidine↗
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Comparison of two commercially available chlorhexidine mouthrinses: II. Effects on plaque reformation, gingivitis, and tooth staining.

Several chlorhexidine mouthwashes are now produced commercially but which differ in concentration and regimen of use. This study compared a 0.1% formulation with a 0.2% formulation for effects on plaque reformation, development of gingivitis, and tooth staining. The investigation was a single blind cross-over design employing 14 volunteers with a high standard of oral hygiene and gingival health. The rinses were used twice a day during two 19 day periods using the regiments recommended by each manufacturer and as a replacement for mechanical oral hygiene practices. A baseline zero plaque score was obtained at the beginning of each period with a 16-day washout allowed between the two periods. Parameters of gingival inflammation were scored at baseline and then, together with plaque and tooth stain scores, at 12 and 19 days. All indices of gingival inflammation and plaque were significantly increased at days 12 and 19 with the 0.1% mouthwash formulation. Little evidence of tooth staining was noted with the 0.1% formulation. The 0.2% mouthwash produced the characteristic staining noted with most chlorhexidine preparations. Based on the findings of this study and a previous laboratory investigation, it is concluded that the reduced antiplaque activity of the 0.1% formulation resulted from inactivation of chlorhexidine within the product rather than from the reduced dose of chlorhexidine used.

Adult↗
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Children of divorce.

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Counseling↗
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Growth factor regulation of 17 beta-hydroxysteroid dehydrogenase activity in a human ovarian cell line: modulation by 17 beta-estradiol.

We have examined the effects of IL-6 and bFGF on growth and reductive 17 beta-hydroxysteroid dehydrogenase (17-HSD) activity in a human ovarian cell line A2780 under defined culture conditions (standard RPMI (GM+PHR), phenol red-free RPMI (GM-PHR), or GM-PHR supplemented with 17 beta-estradiol). In media GM+PHR, neither factor influenced terminal cell density. However there was a 2-fold stimulation in 17-HSD activity (E1- > E2) in the presence of IL-6 and a 3-fold increase in the presence of bFGF. Cells cultured GM-PHR showed a 25-30% reduction in terminal cell density compared with cells cultured GM+PHR, and addition of factors resulted in a modest reduction (10-15%) in cell growth, with no detectable changes in 17-HSD. Addition of 17 beta-estradiol to GM-PHR cultures increased terminal cell density by up to 3-fold, with no effect on 17-HSD, and when combined with IL-6 or bFGF, a synergistic effect on growth was observed, but 17-HSD levels were unchanged. Our results suggest that cultured ovarian tumour cells respond to paracrine factors likely to be present in the ovary in vitro, and there is a possible interactive effect of estromedins with these factors.

Cell Division↗