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Biomedical subjects

A Ribes

Publications and source records attributed to A Ribes.

At least 55 records · Page 3Linked to original sources
PubMed1996

Ethylmalonic aciduria is associated with an amino acid variant of short chain acyl-coenzyme A dehydrogenase.

Ethylmalonic aciduria is a common biochemical finding in patients with inborn errors of short chain fatty acid beta-oxidation. The urinary excretion of ethylmalonic acid (EMA) may stem from decreased oxidation by short chain acyl-CoA dehydrogenase (SCAD) of butyryl-CoA, which is alternatively metabolized by propionyl-CoA carboxylase to EMA. We have recently detected a guanine to adenine polymorphism in the SCAD gene at position 625 in the SCAD cDNA, which changes glycine 209 to serine (G209S). The variant allele (A625) is present in homozygous and in heterozygous form in 7 and 34.8% of the general population, respectively. One hundred and thirty-five patients from Germany, Denmark, the Czech Republic, Spain, and the United States were selected for this study on the basis of abnormal EMA excretion ranging from 18 to 1185 mmol/mol of creatinine (controls < 18 mmol/mol of creatinine). Among them, we found a significant overrepresentation of the variant allele. Eighty-one patients (60%) were homozygous for the A625 allele, 40 (30%) were heterozygous, and only 14 (10%) harbored the wild-type allele (G625) in homozygous form. By overexpressing the wild-type and variant protein (G209S) in Escherichia coli and COS cells, we showed that the folding of the variant protein was slightly compromised in comparison to the wild-type and that the temperature stability of the tetrameric variant enzyme was lower than that of the wild type. Taken together, the over-representation and the biochemical studies indicate that the A625 allele confers susceptibility to the development of ethylmalonic aciduria.

Acyl-CoA Dehydrogenase↗
PubMed1995

The molecular basis of canavan (aspartoacylase deficiency) disease in European non-Jewish patients.

Canavan disease is an infantile neurodegenerative disease that is due to aspartoacylase deficiency. The disease has been reported mainly in Ashkenazi Jews but also occurs in other ethnic groups. Determination of enzymatic activity for carrier detection and prenatal diagnosis is considered unreliable. In the present study, nine mutations were found in the aspartoacylase gene of 19 non-Jewish patients. These included four point mutations (A305E [39.5% of the mutated alleles], C218X [15.8%], F295S [2.6%], and G274R [5.3%]); four deletion mutations (827delGT [5.3%], 870del4 [2.6%], 566del7 [2.6%], and 527del6 [2.6%]); and one exon skip (527del108 [5.3%]). The A305E mutation is pan-European and probably the most ancient mutation, identified in patients of Greek, Polish, Danish, French, Spanish, Italian, and British origin. In contrast, the G274R and 527del108 mutations were found only in patients of Turkish origin, and the C218X mutation was identified only in patients of Gypsy origin. Homozygosity for the A305E mutation was identified in patients with both the severe and the mild forms of Canavan disease. Mutations were identified in 31 of the 38 alleles, resulting in an overall detection rate of 81.6%. All nine mutations identified in non-Jewish patients reside in exons 4-6 of the aspartoacylase gene. The results would enable accurate genetic counseling in the families of 13 (68.4%) of 19 patients, in whom two mutations were identified in the aspartoacylase cDNA.

Alleles↗
PubMed1995

[Biochemical-histological study of the effects of lithium on various organs of vizcacha (Lagostomus maximus maximus)].

Considering that the vizcacha (Lagostomus maximus maximus) is a very Lithium sensitive rodent, we planned a biochemical-histological study injecting IP doses of 1 mEq/kg/day LiCl during one month to adult vizcachas, and they were divided into three lots: Lot I the optical microscopy revealed evident renal, gonadal, hyphophyseal and adrenal damages; the biochemical analysis showed that Li significantly decreased the female serum LH levels while testosterone and estradiol levels were not affected. The male Li serum values resulted to be significantly higher than those of female animals. The damage was greater in male specimens. Lott II: the tissue recovery from the damage observed in Lot I was the following: total in hyphophysis, partial in testis, the same in kidney and was enhanced in adrenal and ovary. The Li renal clearance was determined in Lot III verifying no changes in both sexs. According to our results, Li (1 mEq/kg/day during one month) produce modifications in different tissues probably the gonadal damage may be consequence of a direct Li effect and not for a hyphophysis alteration, since in male vizcacha the LH serum level was not changed. In regard to the selective effect in the suprarenal glomerulus structure, this Li effect is produced via hyphophysis. In conclusion, the selective effect of Li on adrenal and gonada organs of this rodent is a contribution in order to warm about the possible reproduction of such effects in human beings.

Adrenal Glands↗
PubMed1992

Glutaric aciduria type I: unusual biochemical presentation.

We describe a patient with glutaryl-coenzyme A dehydrogenase deficiency, demonstrated by a residual enzyme activity of only 1% in cultured fibroblasts. Although the clinical presentation was typical of glutaric aciduria type I, the urine concentrations of glutaric, glutaconic, and 3-hydroxyglutaric acids remained normal, even during episodes of clinical decompensation. An increased free glutarate level was demonstrated only in cerebrospinal fluid.

Carnitine↗
PubMed1990

Methylmalonic aciduria with homocystinuria: biochemical studies, treatment, and clinical course of a Cbl-C patient.

A patient with infantile onset methylmalonic aciduria and homocystinuria (Cbl-C mutant) is described. Therapy with hydroxycobalamin, folate and vitamin B6 improved his condition. As hypomethioninaemia and homocystinaemia persisted, he was treated with intramuscular methylcobalamin, but without success. Treatment with betaine started at 25 months of age, normalized plasma methionine and elicited disappearance of homocystinaemia. Results of biochemical studies in cultured fibroblasts paralleled those described for other Cbl-C patients except that methylmalonyl-coenzyme A mutase activity in disrupted fibroblasts was in the normal range.

Betaine↗