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Biomedical subjects

G Vaca

Publications and source records attributed to G Vaca.

At least 37 records · Page 2Linked to original sources
PubMed1985

46,XX,-12,+der(12),rcp(3;12)(p25.1;p13.31)pat karyotype in a girl. Probable subregional assignment of glyceraldehyde-3-phosphate dehydrogenase locus to 12p13.1----p13.31 by exclusion mapping.

A female infant with partial trisomy 3p and a terminal deletion 12p, due to a paternal (3;12)(p25.1;p13.31) translocation is described. Normal glyceraldehyde-3-phosphate (GAPD) activity in the proposita tentatively excludes GAPD locus from the deleted segment. Therefore, the region for this locus is reduced to 12p13.1----p13.31.

Abnormalities, Multiple↗
PubMed1984

Sorbitol dehydrogenase deficiency in several pig tissues: potential implications for studies of experimental diabetes.

Screening for red blood cell sorbitol dehydrogenase deficiency in 12 different mammalian species was performed. A wide inter-species variability in red cell sorbitol dehydrogenase with a virtually complete deficiency in pigs was observed. Aldose reductase and sorbitol dehydrogenase activities in 12 different pig tissues also were measured. Aldose reductase activity was present in all the tissues studied, whereas organ specificity for sorbitol dehydrogenase was observed. Sorbitol dehydrogenase activity was not detectable in lenses, among other tissues, making the pig a potential model for studies in experimental diabetes, particularly for the investigation of sorbitol dehydrogenase deficiency as a risk factor in the development of cataracts.

Aldehyde Reductase↗
PubMed1983

Neurospora crassa mutant impaired in glutamine regulation.

The final products of the catabolism of arginine that can be utilized as nitrogen sources by Neurospora crassa are ammonium, glutamic acid, and glutamine. Of these compounds, only glutamine represses arginase and glutamine synthetase. We report here the isolation and characterization of a mutant of N. crassa whose arginase, glutamine synthetase, and amino acid accumulations are resistant to glutamine repression (glnI). This mutant has a greater capacity than the wild type (glns) to accumulate most of the arginine and some of the glutamine in osmotically sensitive compartments while growing exponentially. Nonetheless, the major part of the glutamine remains soluble and metabolically available for repression. We propose that the lower repression of glutamine synthetase by glutamine in this mutant could be a necessary condition for sustaining the higher flow of nitrogen for the accumulation of amino acids observed in ammonium excess and that, if glutamine is the nitrogen signal that regulates the arginine accumulation of the vesicle, the glnr mutant has also escaped this control. Finally, in the glnr mutant, some glutamine resynthesis is necessary for arginine biosynthesis and accumulation.

Amino Acids↗
PubMed1983

A fluorimetric method for red blood cell sorbitol dehydrogenase activity.

A new fluorimetric method for the quantification of red blood cell (RBC) sorbitol dehydrogenase is described. It is based on the oxidation of sorbitol to fructose, in presence of NAD+, catalysed by the RBC-sorbitol dehydrogenase. The quantity of NADH formed is then measured in a filter fluorimeter. Comparison with an indirect spectrophotometric assay yielded good correlation; however, the present method offers several advantages: it is more rapid, simple and inexpensive. It should be useful to screen for sorbitol dehydrogenase deficiency in large numbers of individuals, particularly patients with diabetes or cataracts.

Erythrocytes↗
PubMed1983

On the screening for inborn errors of galactose metabolism.

The utility of a simplified diagram of procedures for screening specimens for genetic disorders in galactose metabolism is stressed. Both, early detection and institution of the dietetic treatment are imperative since these inherited disorders have clinical and pathological consequences which can be very severe in galactose-1-phosphate uridyltransferase and uridine diphosphate galactose-4-epimerase deficiencies.

Carbohydrate Epimerases↗
PubMed1982

G-6-PD Guadalajara. A new mutant associated with chronic nonspherocytic hemolytic anemia.

This paper describes a new G-6-PD variant designated Guadalajara, which was found in a Mexican boy suffering from chronic hemolytic anemia. The red cell enzyme activity of the subject is about 14%. The mutant enzyme showed rapid electrophoretic mobility, slightly increased affinity for glucose-6-phosphate, slightly decreased affinity for NADP+, moderately elevated utilization of substrate analogues, and normal heat stability, pH curve, and inhibition by NADPH. G-6-PD Guadalajara differs from all previously reported variants and is the first variant associated with chronic hemolysis found in Mexico.

Anemia, Hemolytic, Congenital↗
PubMed1982

Red blood cell sorbitol dehydrogenase deficiency in a family with cataracts.

Sorbitol dehydrogenase (SORD) was quantitatively assayed in a family in which four out of five brothers and their father had bilateral cataracts. Three sibs (two of them with cataracts) and both their father and paternal grandfather had SORD activity of about 25% of the reference values; of the other two affected sibs one had about 50% and the other had 75%; the mother and two paternal uncles had about 75%. These results do not define a clear cataract-SORD deficiency etiopathogenic relationship, nevertheless, they strongly suggest activity polymorphism in human red cell SORD, which would be highly relevant not only to the study of cataracts but of other major complications in diabetes.

Cataract↗
PubMed1982

Sorbitol dehydrogenase (EC.1.1.1.14) polymorphism in human seminal plasma.

Sorbitol dehydrogenase was electrophoretically determined in 173 different samples of human seminal plasma in cellulose acetate as support media. This method permitted the identification of three phenotypes : one with a slow band, one with a fast band and the third with both slow and fast bands. These findings can be explained either by the presence of two alleles at a different SORD locus determining the enzyme in seminal plasma or by the formation of secondary isozymes.

Electrophoresis, Cellulose Acetate↗
PubMed1982

Tetrasomy 9p: clinical aspects and enzymatic gene dosage expression.

A girl aged 13 years and 9 months with a phenotypic appearance of 9p trisomy was studied. Chromosome analysis of peripheral blood lymphocytes revealed a 9p tetrasomy [47,XX,+i(9p)] with no evidence of mosaicism. Biochemical studies corroborate the gene dosage effect for galactose-1-phosphate uridyltransferase. The roentgenological findings were quite similar to those of the 9p trisomy except for hypoplastic and angulated ribs, and malformed vertebral bodies, which are probably exclusive of the tetrasomic state.

Adolescent↗
PubMed1982

Abnormal hemoglobins in Northwestern Mexico.

Blood samples from 9,929 individuals in Northwestern Mexico were assayed for abnormal hemoglobins (Hbs). alpha-thal, beta-thal, beta s and beta c traits, as well as rare abnormal Hbs were observed with variable low frequencies (0 to 0.45%). Eight out of eleven rare abnormal Hbs detected so far have been characterized: Three Hb Riyadh, one Hb J Georgia, one Hb Fannin-Lubbock, one Hb Chiapas and two Hb Tarrant. These results suggest that abnormal Hbs do not constitute a regional public health problem and reflect a wide ethnologic heterogeneity.

Female↗
PubMed1982

Screening for inborn errors of the erythrocyte metabolism in Northwestern Mexico.

Data from a program aiming to the detection of inborn errors of the erythrocyte metabolism (IEEM) in Northwestern Mexican populations are presented. 5,998 individuals were studied and divided in 5 groups: a) 1,022 full-term newborns without jaundice; b) 872 randomly selected full-term newborns; c) 3,243 full-term newborns with jaundice; d) 54 patients with hemolytic anemia, and e) 807 professional blood donors. In groups b, c and d screening for 9 out of 14 IEEM clearly associated with hemolysis was carried out by means of enzymatic fluorescent procedures. In groups a and e only G-6-PD deficiency was investigated. The results suggest that 0.34%, 0.77%, 24% and 0.37% of the individuals from groups b, c, d and e, respectively, have an IEEM. The frequency of G-6-PD deficiency was 0, 0.43%, 1.1%, 30.3% and 0.37% in the males from groups a, b, c, d and e, respectively. The IEEM as a cause of neonatal jaundice seem not to be a public health problem in the studied populations. Systematic screening for: 1) G-6-PD deficiency in newborns with jaundice and 2) IEEM in patients with hemolysis, is recommended.

Anemia, Hemolytic↗
PubMed1981

Meiotic arrest at first spermatocyte level: a new inherited infertility disorder.

Three 46,XY phenotypically male, azoospermic brothers out of thirteen sibs from a consanguineous marriage were studied and found to have a unique pattern of testicular histology with arrest of spermatogenesis at the pachytene stage of primary spermatocytes. Endocrinological evaluation showed elevated plasma luteinizing(LH) and normal to elevated follicle-stimulating (FSH) hormones, positive gonadotropin pituitary response to luteinizing hormone-releasing hormone, depletion of LH and FSH levels by exogenous testosterone (T) administration, normal levels of T and dihydrotestosterone hormones, and elevation of T after stimulation with human chorionic gonadotropin hormone. Electrophoretic assay of lactic dehydrogenase isozymes did not reveal band C4 in semen or testicular tissue. These traits seem to constitute a hitherto undescribed form of infertility in which spermatogenesis arrest at the first spermatocyte level is the main feature. The parental consanguinity suggests autosomal recessive inheritance.

Adolescent↗
PubMed1981

alpha, 1-4 Glucosidase activity in human seminal plasma from normal, vasectomized, and subfertile men.

Neutral alpha, 1-4 glucosidase activity was assayed by a spectrophotometric method using p-nitro-phenyl-alpha-D-glucopyranoside as the substrate in the seminal plasma of normal, vasectomized, and oligospermic men. The latter groups showed lower values than the controls. These results suggest that the main source of the alpha, 1-4 glucosidase activity is between the vasectomy site and the tubule, and that the enzyme is related to sperm density or to a spermatogenesis factor.

Glucosidases↗