Biomedical subjects
Publications and source records attributed to L Menezes.
Ultrasound-guided core biopsy of nodes (n = 78) and other lumps (n = 4) in the neck allowed a firm histological diagnosis in 76 of 82 patients (93%). Of the remaining six patients, histological examination was equivocal in four and valueless in two. Of 18 patients with a diagnosis of lymphoma only 3 required excision of the node to provide additional information for the planning of treatment.
The introduction of shigella into a child care centre carries a high risk of secondary spread from person to person within the centre. We report an outbreak of shigellosis in early 1995 that affected 99 children, 17 of their relations, and seven workers i
The pathway of pentose synthesis in glucose-grown cells of Lactobacillus casei was ascertained. Glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were present in glucose-grown cells, while transaldolase and transketolase were present only in traces. This suggested that only the oxidative arm of this pathway was operative in glucose-grown cells. On the other hand, in ribose-grown cells, transaldolase was induced with a concomitant suppression of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. These results were confirmed by the detection of labelled CO2 produced by L. casei grown on [1-14C]glucose. The activities of the enzymes of the oxidative pentose phosphate pathway as also the rate of CO2 formation were higher in the exponential phase of growth as compared to the stationary phase, when the requirement of the cells for pentoses for the formation of DNA and RNA was higher.
Glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) were separated and partially purified from glucose-grown cells of Lactobacillus casei. The enzymes had similar pH optima, thermosensitivity and molecular weights. They had different net charges and their pI values were 5.38 and 4.52, respectively. Histidine, arginine, lysine and cysteine residues were essential for the activity of G6PD, and all the above amino acids with the exception of lysine were required for 6PGD activity. Mg2+ activated 6PGD up to 15 mM concentration, above which it was inhibitory. It had no effect on G6PD activity. G6PD was specific for NADP+, but 6PGD showed some activity with NAD+ as the cofactor, although it was essentially NADP(+)-preferring. Both the enzymes, were inhibited by NADPH. 6PGD was also inhibited by its product, ribulose 5-phosphate. ATP inhibited 6PGD only at subsaturating concentrations of NADP+. The inhibition was sigmoidal in the absence of Mg2+ and hyperbolic in its presence.
We studied 12 patients with absence of the septum pellucidum associated with porencephalies. Seven patients had bilateral and five apparently unilateral defects of the cerebral mantle. The clinical manifestations were relatively mild in half of the patients and limited to isolated partial seizures in one. In one case, extensive calcification was present adjacent to the defects. In two cases, the presence of a cleft was demonstrated only by magnetic resonance imaging, although it had been suspected by computed tomography in one.
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Ethanol metabolism and its influence on serum lactate/pyruvate ratio was studied after intravenous infusion of ethanol in 17 patients: 4 controls, 5 alcoholics with cirrhosis, 4 non-alcoholic cirrhotics and 4 alcoholics without liver disease. All refrained from the use of alcohol and drugs 4 weeks prior to the experiment. After maximal ethanol blood levels were achieved at the end of the infusion, ethanol removal occurred at two different rates. This was probably due to the fact that different volumes of ethanol were distributed with time: a fast period (30 to 60 min) and a slow period (60 to 180 min). The rates of disappearence in the two periods were similar in all groups which suggests that liver cirrhosis, independent of clinical severity and/or chronic alcoholism with previous abstinence from alcohol, does not modify ethanol metabolic rates in the liver. The relation lactate/pyruvate doubled in all cases but it occurred within 30 minutes in the groups without liver disease and within 60 minutes in the cirrhotics. This could account for the decreased liability of cirrhotic patients to alcohol hypoglycemia.
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