Biomedical subjects
Publications and source records attributed to K H Lim.
Schistosomiasis although endemic in the Far East, has not been reported in Singapore. We describe an 83 year-old lady with Schistosoma japonicum infection presenting with bloody diarrhoea. We discuss its diagnosis and postulate the mode of transmission of this infection in urban Singapore.
The ability of ketone bodies to suppress elevated hepatic glucose output was investigated in eight postabsorptive subjects with non-insulin-dependent diabetes mellitus (NIDDM). Infusion of sodium acetoacetate alone (20 mumols/kg/min) for 3 hours increased total serum ketones (beta-hydroxybutyrate and acetoacetate) to approximately 6 mmol/L, but did not reduce plasma glucose (14.0 +/- 0.8 to 12.3 +/- 0.9 mmol/L) or isotopically determined hepatic glucose output (17.5 +/- 1.4 to 12.7 +/- 1.0 mumols/kg/min) more than saline alone. Plasma C-peptide concentrations were unchanged, while serum glucagon increased from 131 +/- 13 to 169 +/- 24 ng/mL (P less than .015) and free fatty acids were suppressed by 43% (0.35 +/- 0.08 to 0.20 +/- 0.06 mmol/L, P less than .025). When sodium acetoacetate was infused with somatostatin (0.10 micrograms/kg/min) to suppress glucagon and insulin secretion, the decrease in both plasma glucose (13.3 +/- 0.9 to 10.2 +/- 0.7 mmol/L) and hepatic glucose output (17.2 +/- 1.6 to 9.4 +/- 0.6 mumols/kg/min) was greater than either acetoacetate or somatostatin infusion alone. Infusion of equimolar amounts of sodium bicarbonate had no effect on glucose metabolism. In conclusion, these results demonstrate that ketone bodies can directly suppress elevated hepatic glucose output in NIDDM independent of changes in insulin secretion, but only when the concomitant stimulation of glucagon secretion is prevented. Ketone bodies also suppress adipose tissue lipolysis in the absence of changes in plasma insulin and may serve to regulate their own production.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Autologous saphenous vein has proved to be a satisfactory conduit for use in coronary artery bypass grafting. Unfortunately, it is not always available, and substitute material must sometimes be used. When satisfactory autologous veins were not available and the internal mammary arteries were unsuitable, cryopreserved homologous saphenous veins were used in 28 patients. A total of 76 grafts were constructed. Cryopreserved homologous veins were used for 61 grafts, autologous saphenous veins for 11 grafts, and the internal mammary artery for 2 grafts. Coronary angiography was performed 8 to 12 days postoperatively in 16 patients. Of the 31 homografts studied, 8 were occluded (26%), 3 were stenotic (9%), and 20 were normal (65%). The one internal mammary artery and six autologous veins studied were all patent. Six patients underwent late catheterization 6 to 12 months postoperatively. Thirteen homografts were studied at late catheterization: 11 were occluded, 1 was severely stenotic, and 1 was mildly stenotic. At late catheterization, the one internal mammary artery studied was patent, and the one autologous saphenous vein was 95% occluded. Results of both early and late catheterization performed on 18 patients demonstrated that of the 35 homografts studied, 17 (49%) were occluded, 3 (9%) had greater than 70% stenosis, 1 (3%) had mild disease, and 14 (40%) were free of disease. One year follow-up data obtained on 26 patients revealed that 4 patients (15%) died of cardiac causes, 2 patients (8%) died of noncardiac causes, 11 patients (42%) have recurrent angina, and 9 (35%) are asymptomatic. It is concluded that use of cryopreserved homologous saphenous veins for coronary artery bypass grafting should be avoided if at all possible.
We investigated the effect of recombinant superoxide dismutase, an oxygen free radical scavenger, on the prevention of reperfusion injury of the ischemic spinal cord. Somatosensory evoked potentials (SEPs) were obtained in 23 dogs. Spinal cord ischemia was produced by cross-clamping the descending thoracic aorta just distal to the origin of the left subclavian artery through a left thoracotomy. Mean proximal aortic blood pressure was maintained between 90 and 100 mm Hg by partial exsanguination. Serial SEPs were obtained at 60-second intervals until the SEP disappeared. Aortic cross-clamping was continued for 10 additional minutes after the disappearance of the SEP. In Group 1 (N = 8), no medication was given when the aortic cross-clamp was removed. In Group 2 (N = 8), a bolus of 25,000 units of superoxide dismutase was injected into the proximal aorta prior to removal of the aortic cross-clamp, and was followed by 5,000 units per minute for 10 minutes after release of the cross-clamp. In Group 3 (N = 7), 50,000 units of superoxide dismutase was administered as a bolus prior to removal of the aortic cross-clamp, followed by an additional 10,000 units per minute for 10 minutes as in Group 2. The postoperative neurological status was assessed by Tarlov's criteria. There was no significant difference in aortic cross-clamp time among the three groups. Paraplegia developed in 4 animals in Group 1; the remaining 4 dogs had paraparesis. In Group 2, paraparesis developed in 2 of 8 dogs; the other 6 had no neurological injury. All the animals in Group 3 had complete recovery.(ABSTRACT TRUNCATED AT 250 WORDS)
This investigation examined the efficacy of right atrial-pulmonary artery bypass (RA-PA) during acute ischemia of the right ventricle. The right coronary artery (RCA) was ligated in 25 open chest, open pericardium sheep. Control animals (n = 15) were resuscitated with only intravenous fluids. In the experimental animals (n = 10) RA-PA bypass was initiated 5 minutes after right coronary occlusion. Sixty percent (9/15) of the control animals died within 90 minutes of RCA occlusion from refractory ventricular arrhythmia or right ventricular failure. Four of 10 RA-PA animals died within 2 hours of RCA occlusion from severe pulmonary hemorrhage and arterial oxygen desaturation when high flow rates (2.5 to 3.5 L/min) were initially instituted. In these animals, lung histologic findings demonstrated extensive hemorrhage into the alveolar spaces. After 6 hours of RCA occlusion in the six surviving control animals, there were significant increases in central venous pressure and right ventricular end-diastolic cord length (relative ventricular volume change measured by ultrasonic crystal analysis), and a significant decrease in the cardiac output. In contrast, during RCA occlusion in the six surviving animals on RA-PA bypass, cardiac output was well maintained, and there was a significant decrease in central venous pressure and end-diastolic length. The percent of change from baseline in end-diastolic length correlated inversely with the percent of change from baseline in cardiac output (r = -0.81, p less than 0.01). By crystal violet and triphenyltetrazolium chloride dye techniques, the mean percentage area of necrosis to area of risk was significantly less for the RA-PA group compared with the control group (5.6% versus 67.1%, p less than 0.0001). In this experimental model, RA-PA bypass effectively unloaded the acutely ischemic right ventricle, maintained systemic cardiac output, and significantly reduced right ventricular infarction size. Further investigations with this ventricular support modality are needed to determine its effects on pulmonary pathophysiology.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A serial clinical, hematologic, and cytogenetic study was done on a baby with Down's syndrome in whom a myeloid leukemoid reaction developed at birth that spontaneously regressed within a month only to relapse two years later to an acute undifferentiated stem cell leukemia. He died 1 1/2 months after onset. The unresolved controversy of the diagnosis of the congenital leukemia-like state is discussed. The importance of following up such patients with apparent remission of their congenital leukemia-like disorder is emphasized.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.