Biomedical subjects
Publications and source records attributed to K Singh.
Hernia through the foramen of Morgagni is uncommon in adults. Chronic gastric volvulus within the foramen of Morgagni is very rare. In this report, we describe a patient who presented with symptoms of gastric outlet obstruction due to chronic intermittent gastric volvulus in the foramen of Morgagni.
Norplant contraceptive implants are silastic implants containing levonorgestrel. This study describes our experience with 100 acceptors of Norplant implants in Singapore. There were no infections at the site after the implants were inserted. No pregnancies occurred during the first year of use. Disruptions of menstrual rhythm was the main complaint. However, the incidence of menstrual irregularities appeared to diminish with time. Implant users have tolerated this early disruption of their menstrual rhythm well and the continuation rate at the end of the year was 96.6 percent. Thus, it appears that Norplant contraceptive implants offer a highly effective means of contraception which should become well accepted in the near future.
Norplant-2 contraceptive implants consist of two silastic rods in which levonorgestrel has been incorporated with the polymer. This study describes our experience with 100 acceptors of the Norplant-2 rods in Singapore. No pregnancies occurred during the first year of use. Menstrual irregularities was the main complaint associated with the use of Norplant-2. However, the incidence of menstrual irregularities appeared to diminish with time and the continuation rate at the end of one year was 95.0 per cent. Thus, it appears that the Norplant-2 rod systems offer a highly effective, convenient means of contraception which should be well accepted in future.
A longitudinal study of coagulation parameters was carried out on 100 Singapore acceptors using the levonorgestrel subdermal implants Norplant-2 rods for contraceptive purposes. At the end of 1 year of use, results from this on-going study indicates that these acceptors have an enhanced potential for hypercoagulation with a significant shortening of their prothrombin time and activated partial thromboplastin time. They also have an increased predisposition to thrombosis as evidenced by significant increases in platelet count and aggregability. A number of other parameters achieved statistically significant differences by the end of one year but since the results were within the normal accepted range, they were therefore unlikely to be of much clinical importance.
In this longitudinal study involving 100 Singaporean acceptors, the effects of Norplant-2 rods on metabolic function was evaluated. With respect to liver function, the results indicate possible hepatocellular dysfunction. There was a significant rise in mean serum bilirubin from 0.54 mg/dl to 0.85 mg/dl after 12 months of use (p less than 0.001). Furthermore, there was also a significant fall in total proteins from 7.37 gm/dl to 7.12 gm/dl (p less than 0.001) and serum globulin from 3.18 gm/dl to 2.84 gm/dl (p less than 0.001). As regards lipid metabolism, we have demonstrated significant decreases in mean serum triglycerides (1.04 mmol/l to 0.83 mmol/l), p less than 0.001; total cholesterol (5.04 mmol/l to 4.64 mmol/l), p less than 0.001; and LDL-cholesterol (3.36 mmol/l to 3.10 mmol/l), p less than 0.001 after one year of use. There was a small fall in the HDL-cholesterol (1.21 mmol/l to 1.16 mmol/l) after 12 months of use; this fall was not significant. Despite this, there was a rise in the HDL-cholesterol/Total cholesterol - HDL-cholesterol ratio (0.258 cf 0.244; p less than 0.05) after 1 year of use. As we have not incorporated a simultaneous non-pill treated control group, the observed changes in lipoprotein lipids could be attributed to extraneous factors such as diet, exercise or other environmental changes. Nevertheless, the findings, though speculative, indicate Norplant-2 use to be non-contributory to cardiovascular risk and indeed it may be a protective factor against such risks in this population. The use of Norplant-2 rods was not associated with any significant effect on glucose tolerance after 12 months of use.
In this longitudinal study involving 100 Singaporean acceptors, the effects of NORPLANT on their metabolic function was evaluated. With respect to liver function, the results indicate possible hepatocellular dysfunction; there was a significant rise in mean serum bilirubin from 0.55 mg/dl to 0.87 mg/dl after 12 months of use (p less than 0.001). This rise could not be attributed to a skewed distribution of mean value as the difference achieved statistical significance using the paired 't' test as well as the Wilcoxon signed rank test using the median distribution. In terms of the effects of NORPLANT on lipid metabolism, we have demonstrated a significant rise in HDL-cholesterol (1.08 mmol/l +/- 0.34 to 1.13 mmol/l +/- 0.24; p less than 0.05) with significant decreases in mean serum triglycerides (1.21 mmol/l +/- 0.74 to 0.89 mmol/l +/- 0.45; p less than 0.002) and total cholesterol (5.05 mmol/l +/- 1.02 to 4.64 mmol/l +/- 0.81; p less than 0.001) after one year of use. There was also a significant rise in the HDL-cholesterol/total cholesterol ratio after 1 year (0.225 +/- 0.086 cf 0.250 +/- 0.059; p less than 0.001). As we have not incorporated a simultaneous non-pill treated control group, the observed changes in lipoprotein lipids could be attributed to extraneous factors such as diet, exercise or other environmental changes. Nevertheless, the findings though speculative indicate NORPLANT use to be non-contributory to cardiovascular risk and indeed it may be protective factor against such risks in this population. The use of NORPLANT was not associated with any significant effect on glucose tolerance after 12 months of use.
A longitudinal study of coagulation parameters was carried out on 100 Singaporean acceptors using the levonorgestrel subdermal implants NORPLANT for contraceptive purposes. At the end of 1 year of use, results from this on-going study indicate that these subjects may have an increased predisposition to thrombosis as evidenced by significant increase in platelet count and aggregability. The results also show that NORPLANT acceptors may have an enhanced potential for hypercoagulation - with a significant shortening of their Prothrombin Time and Activated Partial Thromboplastin Time and increases in Factors V and X. As previously documented, mean values for haemoglobin and haematocrit were significantly elevated by the end of 1 year. A number of other parameters achieved statistically significant differences by the end of 1 year but these were probably due to the large sample size involved and were therefore not likely to be of much clinical importance.
An analysis of 9399 consecutive singleton births delivered at this unit is presented. The incidence of low birthweight (less than 2500 g) was 7.4%. Further analysis of the 698 low birth weight babies indicated that a variety of socio-demographic risk factors are operational in the etiology of low birthweight. Many of these are preventable before pregnancy so that the implementation of preventive Public Health measures utilising appropriate technology at least in developing countries may be socially and economically preferable to continued financial investment in intensive perinatal services.
Leukotriene A4 epoxide hydrolase from dog lung, a soluble enzyme catalyzing the hydrolysis of leukotriene A4 (LTA4) to leukotriene B4 (LTB4) was partially purified by anion exchange HPLC. The enzymatic reaction obeys Michaelis- Menten kinetics. The apparent Km ranged between 15 and 25 microM and the enzyme exhibited an optimum activity at pH 7.8. An improved assay for the epoxide hydrolase has been developed using bovine serum albumin and EDTA to increase the conversion of LTA4 to LTB4. This method was used to produce 700 mg of LTB4 from LTA4 methyl ester. The partial by purified enzyme was found to be uncompetitively inhibited by divalent cations. Ca+2, Mn+2, Fe+2, Zn+2 and Cu+2 were found to have inhibitor constants (Ki) of 89 mM, 3.4 mM, 1.1 mM, 0.57 mM, and 28 microM respectively Eicosapentaenoic acid was shown to be a competitive inhibitor of this enzyme with a Ki of 200 microM. From these inhibition studies, it can be theorized that the epoxide hydrolase has at least one hydrophobic and one hydrophilic binding site.
'Home made brew' (illicit liquor) is often consumed in rural areas of India. Forty-six such alcohol samples were collected from different areas to assess total acidity, pH and ethanol content. The mean ethanol content was 16.47% (v/v) (range 1.11-36.88%). Total acidity ranged between 0.56 and 10.88 with the mean of 2.85 g of sodium hydroxide/l. The mean pH was 4.20 (range 2.70-9.41).
Alkaline hydrolysis of leukotriene A4 methyl ester to leukotriene A4 was studied in either methanol or acetone. Hydrolysis in acetone yielded larger amounts of leukotriene A4 than similar hydrolysis in methanol. The maximum amount was obtained 60 minutes after the beginning of the hydrolysis. Leukotriene A4, as well as leukotriene B4 methoxy isomers were obtained from hydrolysis of leukotriene A4 methyl ester in methanol. It was found that initial leukotriene A4 methyl ester concentration affected the amount of LTA4 produced during the hydrolysis. The maximum concentration of leukotriene A4 was obtained by hydrolyzing solutions of 0.25 mg/ml leukotriene methyl ester in acetone. Spontaneous degradation of leukotriene A4 occurred when it was diluted with tris buffer. Addition of bovine serum albumin to the tris buffer significantly prolonged the half life of leukotriene A4.
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RNA polymerase III (pol III) transcribes the highly repeated murine B2 elements. We showed previously that the B2 RNAs are induced 4-fold in normal growing cells and 20-fold in simian virus 40-transformed cells relative to the levels in normal confluent cells. By employing chromatin as a template in a partially purified pol III transcription system, we now demonstrate that the augmented expression results from the formation of pol III transcription complexes on previously inactive B2 genes. Extracts prepared from normal growing cells and transformed cells transcribed cloned pol III templates 5-fold more efficiently than extracts from normal confluent cells. This increase was attributed to 5-fold greater levels of factor IIIC; the levels of pol III and factor IIIB were the same in all extracts. We discuss how the levels of IIIC and differing accessibility of this factor to repressed B2 genes mediate the formation of pol III transcription complexes in normal growing and transformed cells.
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