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Biomedical subjects

M M Vieira

Publications and source records attributed to M M Vieira.

11 recordsLinked to original sources

Walker-Warburg syndrome. Report of two cases.

The purpose of this study is to describe two infants that were diagnosed with Walker-Warburg syndrome (WWS), a rare form of congenital muscular dystrophy (CMD). They were studied in their clinical, laboratory, and neuroradiologic features. The index case had a brain magnetic resonance imaging (MRI) and the second patient had a head computerized tomography (CT). In addition, a literature review was performed to describe the main forms of CMD. The index case fulfilled all criteria for WWS. A brain MRI performed at age 4 months served to corroborate the clinical diagnosis, showing severe hydrocephalus, type II lissencephaly, cerebellar vermian aplasia, and a hypoplastic brain stem. The authors were able to establish a retrospective diagnosis of WWS in the index case's older sister, based upon her clinical picture and head CT report.

Abnormalities, Multiple↗

An improved method for butyrylcholinesterase phenotyping.

An improved method for the identification of butyrylcholinesterase phenotypes is proposed. It is based on modifications of a method that uses alpha-naphthyl acetate as substrate and DL-propranolol and Ro2-0683 as inhibitors. The proposed modifications make the method more rapid and increase the accuracy of the determinations of the phenotypes tested (BCHE U, BCHE UF, BCHE UA, BCHE AK, BCHE AF, and BCHE A). These modifications make the method even more adequate for population studies and clinical routine.

Alleles↗

The C5 isozyme of serum cholinesterase and adult weight.

The relationship between the CHE2 locus of serum cholinesterase (BChE) and adult human weight was studied in a sample of 225 CHE2 C5+ individuals and 225 CHE2 C5- controls matched for sex, height, age and race. With respect to the intensity of the C5 band staining (scored 1-6), 113 individuals had faint C5 bands (scores 1-3) and 112 intense C5 bands (scores 4-6). The individuals with intense CHE2 C5+ phenotype showed a significantly lower mean adult weight (64.66 +/- 0.73 kg) when compared to their controls (70.59 +/- 0.97 kg) and a significant reduction in weight variance (59.81 and 105.18, respectively). Individuals with faint C5 bands, although showing a negative correlation between weight and C5 band intensity, did not differ from their controls in mean weight.

Adolescent↗

Muscle D-glyceraldehyde-3-phosphate dehydrogenase from Caiman sp. II New data for enzyme characterization.

Muscle GPDH from Caiman sp. was activated by dithioerythritol and 2-mercaptoethanol. Maximal activation was obtained with the reducing agent at 10mM final concentration. The binding of NAD to the apoenzyme occurs at four sites per tetramer, but ligand affinity seems to be heterogeneous. Incubation of the holo or the apoenzyme with NADH at 37 degrees C caused inactivation of the enzyme, with partial loss of SH-titrable groups. Incubation of the holo or the apoenzyme with G3P at 37 degrees C caused partial inactivation of the enzyme. The apoenzyme was demonstrated to be more stable than the respective holoenzyme, in the assay conditions used.

Alligators and Crocodiles↗

Induction and catabolite repression of L-rhamnose dehydrogenase in Pullularia pullulans.

The growth of Pullularia pullulans on L-rhamnose (6-deoxy-L-mannose) as the sole carbon source induces the synthesis of L-rhamnose dehydrogenase, a nicotinamide adenine dinucleotide-dependent enzyme that catalyzes the oxidation of the deoxy sugar to L-rhamnonolactone. The enzyme induction is inhibited by cycloheximide, suggesting de novo synthesis. The presence of d-glucose (0.2%) or D-galactose (0.2%) simultaneously with the inducer in the induction medium produced 50% repression of dehydrogenase synthesis, but no effect was detected with D-fructose and D-mannose at the same concentration. High levels of D-glucose (2%), under maximal catabolite repression conditions, produced a complete inhibition of enzyme synthesis.

Carbohydrate Dehydrogenases↗

Measurement of body composition changes during hemodialysis by bioimpedance analysis.

Monitoring of fluid exchanges during hemodialysis is essential for the safety and efficacy of the procedure. Bioimpedance analysis has been used for the measurement of body compartments in many settings, but experience during hemodialysis is relatively scare. In a prospective study of 28 cases of chronic renal failure treated by long-term hemodialysis on an outpatient basis, body composition studies were done immediately before and after the dialysis session. Methods included body weight, serum albumin, hematocrit, hemoglobin, sodium and osmolality. These variables were compared with impedance (BIA) findings, namely lean body mass, body fat, total water, extra and intra-cellular water, third space, and exchangeable sodium/potassium ratio. Patients lost weight and improved hematocrit, hemoglobin, osmolality and serum sodium during the therapy, and BIA measurements were consistent with these changes. Lean body mass and body fat markedly changed along the dialysis session (respectively -24.5% and + 7.5%), and these results were out of proportion regarding known gains and losses in that period. It is concluded that BIA was useful for monitoring water fluxes during hemodialysis, but provided unreliable information about body fat and lean body mass.

Adult↗