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Biomedical subjects

T Ng

Publications and source records attributed to T Ng.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effect of exogenous pyruvate on acrylamide neuropathy in rats.

The protective effect of exogenous sodium pyruvate on the distal-proximal progression of experimental acrylamide neuropathy in rats was examined. Incorporation of 2% (w/w) sodium pyruvate powder in the diet of rats receiving subcutaneous injections of an aqueous solution of acrylamide (35 mg/kg/day, 5 days/week) retarded the onset and development of functional, morphological, and biochemical measures of acrylamide neuropathy. Pyruvate supplementation did not alter hexobarbital sleep time or zoxazolamine paralysis time, two in vivo measures of microsomal mixed-function oxidase activity, and the disposition of radioactivity in plasma or sciatic nerve following subcutaneous injection of [14C]acrylamide. Although acrylamide can interfere with energy metabolism at a variety of sites where pyruvate can rescue neurons (axons), the data of this study are consistent with our earlier hypothesis that acrylamide neuropathy may be associated with a glycolytic deficit. The exact site of pyruvate protection is unknown. Exogenous pyruvate is perhaps utilized by axons to circumvent toxin-induced glycolytic inhibition and provide chemical energy for fast axonal transport.

Acrylamide↗
PubMed1989

Changes in the hippocampus and the cerebellum resulting from hypoxic insults: frequency and distribution.

Detailed neurohistological studies were undertaken on 35 cases of cardiac arrest, 17 of hypoglycaemia and 16 of status epilepticus. It was found that the frequency and pattern of selective vulnerability in the hippocampus were similar following cardiac arrest, hypoglycaemia and status epilepticus with the exception that the lateral limb of the dentate fascia was more frequently involved in hypoglycaemia than in the other two groups of cases. Within each group, however, CA1 was the most vulnerable. The cerebellum was less frequently affected in hypoglycaemia and status epilepticus than after cardiac arrest. These findings are compared with recent experimental studies in the rodent which have suggested that the pattern of neuronal damage in each of the three conditions is different.

Cerebellum↗
PubMed1989

Pretransplant assessment of renal viability by phosphorus-31 magnetic resonance spectroscopy. Clinical experience in 40 recipient patients.

A group of 40 cadaveric kidneys was studied just prior to planned transplantation to further assess the applicability of 31P-MRS in the analysis of clinical renal transplant viability. Renal intracellular high-energy phosphorus metabolites (ATP [or NADP], phosphomonoester [PME] and inorganic phosphate [Pi]) and pH were measured noninvasively with MRS surface coils external to cold storage containers. Pretransplant MRS parameters were correlated with subsequent renal function in recipient patients (measured one week postoperatively by the need of dialysis, drop in serum creatinine, urine output, and 123I or 131I Hippuran assessed renal tubular function). ATP and NADP was detected in eleven kidneys and was significantly (P less than 0.001) associated with the best renal function posttransplantation. These kidneys also had the highest PME/Pi ratios (1.66-0.54), while lower ratios (0.36-0.10) were associated with prolonged acute tubular necrosis. The PME/Pi ratios significantly (P less than 0.0001) correlated with subsequent clinical renal function, whereas cold storage times (37 +/- 10 hr) or intracellular renal pH (6.53-7.91) did not. These preliminary data suggest that MRS is a noninvasive, nondestructive and sterile method for assessing clinical viability during hypothermic storage of human cadaver kidneys and the subsequent recovery of renal function postrenal transplantation.

Adenosine Triphosphate↗
PubMed1987

Circumumbilical versus transumbilical abdominal incision.

One hundred and fifteen patients were entered into a prospective randomized trial to establish whether midline abdominal incisions through the umbilicus produced any differences in the incidence of wound infection or failure when compared with the more conventional midline incision skirting around the umbilicus. No significant difference was shown between wound infection rates in 58 transumbilical and 51 circumumbilical incisions. Follow-up of surviving patients for at least one year showed no difference in incisional hernia rate between the two groups of patients. No problems were encountered in making the incisions through the umbilicus, but skirting the umbilicus was felt to cause problems with slewing of the scalpel blade, and asymmetry of the scar in 13 circumumbilical incisions. This study has shown that the practice of avoiding the umbilicus in midline abdominal surgery serves no useful purpose.

Adult↗
PubMed1987

Effects of catheter size on urodynamic measurements in men undergoing elective prostatectomy.

Thirty men undergoing prostatectomy for symptoms of bladder outflow obstruction and low measured maximum flow rates (20 before and 10 after operation) were studied by means of urodynamic investigation. Paired studies were performed on each patient using a large catheter assembly (4 and 10 F) and a small catheter assembly (epidural line, outside diameter 1.1 mm). The order in which the studies were performed was varied randomly. Detrusor pressure at maximum flow rate was significantly greater in the large catheter study (73 +/- 30 cm H2O) than in the small catheter study (65 +/- 27 cm H2O; P less than 0.003). The maximum flow rate was significantly smaller in the large catheter study (8.9 +/- 9.5 ml/s) than in the small catheter study (12 +/- 7 ml/s; P less than 0.001). The increase in detrusor pressure at maximum flow that was noted during the large catheter study was confirmed in the 20 men who were studied before prostatectomy (mean increase 11 +/- 11 cm H2O; P less than 0.001) but no difference was found between the two methods in the 10 men studied after prostatectomy (50 +/- 19 cm H2O and 49 +/- 15 cm H2O). Using a large catheter assembly to perform urodynamic investigations has the advantage that repeated studies can be performed without recatheterisation, but it has the disadvantage of producing a small increase in detrusor pressure at maximum flow in men with symptoms of bladder outflow obstruction. Few errors in diagnosis should result, however, if laboratories using such catheters are aware of this effect and establish their own limit of normal for voiding pressures.

Aged↗
PubMed1978

Genetic markers in Malaysians: variants of soluble and mitochondrial glutamic oxaloacetic transaminase and salivary and pancreatic amylase, phosphoglucomutase III and saliva esterase polymorphisms.

Malaysians of Malay, Chinese, and Indian ancestries were electrophoretically phenotyped for Amy1 and saliva esterase region 1 (Set-1) from saliva, Amy2 from plasma, soluble and mitochondrial GOT and PGM3 from leukocyte and placenta. Kadazans and Bajaus, the indigenous people of Sabah, East Malaysia were surveyed for Amy2. Three types of variants were observed for Amy1, one type for Amy2. Only Indians were found to be polymorphic for Amy1. Two GOTs 2-1 and three GOTm 2-1 variants were found among 281 Chinese while three GOTm 2-1 variants were found among 311 Malays. Malaysian Malays, Chinese, and Indians were found to be polymorphic for Set-1 and PGM3. The gene frequencies in Malays are Set-1F=0.601 +/- 0.021, Set-1S = 0.399 +/- 0.021; PGM13 = 0.788 +/- 0.020, PGM23 = 0.212 +/- 0.020; in Chinese Set-1F = 0.497 +/- 0.028, Set-1S = 0.503 +/- 0.028; PGM13 = 0.745 +/- 0.24, PGM23 = 0.255 +/- 0.024; in Indians, Set-1F = 0.449 +/- 0.031, Set-1S = 0.551 +/- 0.031; PGM13 = 0.755 +/- 0.029, PGM23 = 0.245 +/- 0.029.

Amylases↗
PubMed1975

Stimulation of erythrocyte glutathione reductase activity by flavin adenine dinucleotide (FAD) in Malaysian adults and newborns and their parents.

A study of glutathione reductase (GR) activity and its stimulation by flavin adenine dinucleotide (FAD) in erythrocytes of Malaysian newborns and adults of different racial groups showed that GR stimulation by FAD was greater than 20% in 50% of 866 newborns (57% of Malays, 55% of Indians and 41% of Chinese) and 54% of 274 adults (46% of Malays, 65% of Indians and 45% of Chinese). There was a significant negative correlation between GR activity and percentage FAD stimulation in both newborns and adults in all racial groups. Low GR activity and a high percentage FAD stimulation were more prevalent among parents of newborns with low GR activity than among parents of newborns with higher GR activity. Administration of riboflavin to mothers with low GR activity resulted in increased GR activity and a decreased percentage of FAD stimulation. None of the individuals examined had clear clinical manifestations of riboflavin deficiency. It is concluded that subclinical riboflavin deficiency leading to low GR activity is prevalent in Malaysia among adults and newborns, especially among Malays and Indians.

Adult↗