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Biomedical subjects

G Vaca

Publications and source records attributed to G Vaca.

At least 55 records · Page 3Linked to original sources
PubMed1981

Heterozygosity and homozygosity for the high oxygen affinity hemoglobin Tarrant or alpha 126 (H9) Asp replaced by Asn in two Mexican families.

Two Mexican families from the State of Jalisco have been studied in which 11 members were carriers of Hb Tarrant. Ten subjects were Hb Tarrant heterozygotes producing about 25% of the abnormal hemoglobin. One 9-year-old boy was homozygous for Hb Tarrant. About 50% of his hemoglobin was of the variant type. The heterozygotes had mild erythrocytosis which was considerably more severe in the homozygote. The average P50 value for blood of the heterozygote was 15.1 mm Hg (controls: 22.5 mm Hg) while this value was decreased to 9 mm Hg in the homozygote. The clinical condition of the homozygote is compatible with a mild chronic tissue hypoxia.

Aspartic Acid↗
PubMed1981

A simple screening procedure for glucose phosphate isomerase, phosphofructokinase, aldolase and glyceraldehyde-3-phosphate dehydrogenase deficiencies.

A simple screening procedure for the detection of glucose-phosphate isomerase (GPI), phosphofructokinase (PFK), aldolase (AL) and glyceraldehyde-3-phosphate dehydrogenase (GAPD) deficiencies in blood, is described. These enzymes catalyze the second, third, fourth, and sixth reactions in the Embden-Meyerhof pathway. The procedure is based on the conversion of glucose-6-phosphate to 1,3-diphosphoglycerate (1,3-DPG) which is catalyzed by the sequential action of the GPI, PFK, AL and GAPD. The presence of the enzyme activities is visually estimated by the reduction of NAD+ (non-fluorescent) to NADH (fluorescent) which occurs when 1,3-DPG is formed. Absence of fluorescence indicates the deficiency of anyone of the four enzymes, which are specified by using separately the PFK, AL and GAPD respective substrates.

Anemia, Hemolytic, Congenital↗
PubMed1981

Trisomy 22q12 leads to qter: "aneusomie de recombinaison" of a pericentric inversion.

A 10-day-old girl affected with 22q12 leads to qter "pure" trisomy as a consequence of recombination within a maternal pericentric inversion (22)(p13q12) is described. A phenotypical comparative analysis reveals that the proposita's phenotype is strikingly similar to that of the trisomy 22 syndrome. Arylsulphatase-A activity was above normal levels and interpreted to be the result of a triple dosage of the gene, whose localization would be within the 22q12 leads to qter segment. It is concluded that the segment 22q12 leads to qter, rather than band q11 as previously suggested, plays an important role in determining the phenotypical abnormalities which characterize the trisomy 22 syndrome.

Abnormalities, Multiple↗
PubMed1981

A screening test for phosphoglycerate kinase deficiency.

A simple screening test for the detection of X-linked recessive phosphoglycerate kinase (PGK) deficiency in blood is described. It is based on the conversion of 3-phosphoglycerate to 1,3-diphosphoglycerate catalyzed by the PGK whose activity is visually estimated by the oxidation of NADH (fluorescent) to NAD+ (non-fluorescent) in a coupled reaction with the enzyme glyceraldehyde 3-phosphate dehydrogenase. The disappearance of fluorescence indicates PGK activity in the sample, while the contrary could be due to PGK deficiency. The utility of this test for the study of males with hereditary hemolytic anemia is stressed.

Fluorescence↗
PubMed1981

Detection of inborn errors of metabolism in 1,117 patients studied because of suspected inherited disease.

Results of screening tests for the detection of inborn errors of metabolism in 1,117 consecutive patients are reported in this work; patients came for a second consultation to the Departamento de Genética, Centro Médico de Occidente, IMSS. Simple qualitative test were made that revealed the presence of abnormal metabolites (amino-acids, sugars, organic acids and mucopolysaccharides) in urine and blood as well as identification tests for variant proteins. Results were positive in 138 patients and test for confirmation and/or specificity were made in all patients; in 35 the following diagnosis and incidence were established: classic galactosemia, 2; glucose-6-phosphate dehydrogenase deficiency, 20; essential pentosuria, 1; hyperphenylalaninemia, 5; blue diaper syndrome, 1; cistinuria 1, and type 1 mucopolysaccharidosis, 5.

Amino Acid Metabolism, Inborn Errors↗
PubMed1980

Deficient cell immunity and mild intermittent hyperaminoacidemia in a patient with the Rubinstein-Taybi Syndrome.

A boy aged 2 years 8 months presenting the Rubinstein-Taybi Syndrome (RTS) and a history of recurrent gastrointestinal and respiratory infections was studied. Partial deficient cell immunity and intermittent hyperaminoacidemia and aminoaciduria were ascertained. These findings were interpreted as evidence of phenotypic and probably genetic heterogeneity of RTS.

Abnormalities, Multiple↗
PubMed1980

Post-pubertal female psychosexual orientation in incomplete male pseudohermaphroditism type 2 (5 alpha-reductase deficiency).

An 18 year-old 46,XY female-reared patient with incomplete male pseudohermaphroditism type 2 (5 alpha-reductase deficiency) was studied. She had a male habitus, Wolffian ducts derivatives, normal testes and small phallus; there were no Mullerian duct derivatives nor gynaecomastia. Clinical and genetic data were typical of the diagnosis which was corroborated by endocrinological studies. Normal LH, FSH, testosterone (T) and oestradiol and decreased dihydrotestosterone (DHT) plasma levels before and after hCG administration were found; the T:DHT ratio was highly increased. The histopathological studies of a testis biopsy showed a normal adult male pattern, and the meiotic chromosomes were interpreted as normal. After assessment of her psychosexual orientation, successful surgical and medical therapy to maintain and improve her femaleness was effectuated. The post-pubertal gender role switch commonly observed in these female-reared patients is discussed.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1980

A simple screening procedure for adenylate kinase, hexokinase and glucose-6-phosphate dehydrogenase deficiencies.

A simple screening procedure for the detection of adenilate kinase (AK), hexokinase (Hx) or glucose-6-phosphate dehydrogenase (G6PD) deficiencies in blood, is described. It consists of two assays : in the first, the ATP formed by blood AK is coupled to Hx and G6PD, and in the second, the glucose-6-phosphate formed by blood Hx is coupled to G6PD. The enzyme activities are visually estimated by the reduction of NADP+ (non-fluorescent) to NADH (fluorescent). The appearance of fluorescence in the first assay indicates that the three enzyme activities are present. The absence of fluorescence could be due to the deficiency of any one of the three enzymes; in this case the second assay used in combination with the Beutler's screening test for G6PD permits the detection of the specific enzymatic deficiency.

Adenylate Kinase↗
PubMed1980

Partial trisomy and monosomy 21 in an infant with an unusual de novo 21/21 translocation.

A 3-month-old boy with a 46,XY,--21,+t(21;21)(pter leads to q22.3::q22.3 leads to q11::p11 leads to pter) karyotype, implicating trisomy for the 21q11 leads to 21q22.2 segment and monosomy for the 21q22.3 sub-band, is described. Most of the clinical features corresponded to Down syndrome ; other signs such as large ears, prominent nasal bridge and retromicrognathia were interpreted as the expression of 21q22.3 monosomy. The abnormal monocentric chromosome had satellites and stalks on both ends as a result of a 21q;21q translocation followed by deletion of one centromere region. Despite similar stalk size and NOR-Ag positiveness a significantly higher association frequency of the centrometric end as compared to the acentric end was found. This observation suggests that the satellite association phenomenon is not exclusively NOR-dependent, but that the centromeric and/or p11 regions of acrocentrics also play an important role.

Centromere↗
PubMed1980

A simple assay for uridine diphosphate galactose 4-epimerase activity.

A simple fluorescent test for the activity of blood uridine diphosphate galactose 4-epimerase which converts uridine diphosphate galactose to uridine diphosphate glucose is described. The enzyme activity is visually estimated by to reduction of NAD+ (non fluorescent) to NADH (fluorescent) in a coupled reaction with uridine diphosphate glucose dehydrogenase. The appearance of fluorescence indicates that epimerase activity is present in the sample. The usefulness of this test in newborn screening programs for inborn errors of galactose metabolism is stressed.

Carbohydrate Epimerases↗
PubMed1979

Los Angeles variant of galactose-1-phosphate uridyltransferase (EC 2.7.7.12) in a Mexican family.

Enzymatic activity and electrophoretic mobility of galactose-1-phosphate uridyltransferase (EC 2.7.7.12) were assayed in a Mexican family (8 sibs and their parents) with two galactosemic members. Normal, galactosemic and Los Angeles enzyme variants were identified. A survey of the ethnological backgrounds of the individuals reported to date with the Los Angeles variant showed multiple origins that could be explained by an ancient and widespread gene mutation or, more probably, by further biochemical heterogeneity.

Adolescent↗
PubMed1979

A simple rapid fluorescent assay for adenosine deaminase activity.

A simple, rapid (2 hours), fluorescent test for the activity of blood adenosine deaminase (ADA) is described. The test which can be performed on both heparinized and dried blood, is based on the conversion of adenosine to inosine and ammonium in the presence of ADA. The enzyme activity is visually estimated by the oxidation of NADH (fluorescent) to NAD+ (non-fluorescent) in a coupled reaction with glutamate dehydrogenase. The disappearance of fluorescence indicates ADA activity in the sample. The advantages are discussed of the use of this test for the study of the autosomal recessive severe combined immunodeficiency.

Adenosine Deaminase↗
PubMed1979

Hemolytic anemia caused by glucose-6-phosphate dehydrogenase deficiency.

Results are reported concerning quantitation of glucose -6- phosphate dehydrogenase (G6PD) enzyme activity where in one of the members of a family a clinical diagnosis of acute hemolytic anemia due to G6PD deficiency had been established. In the propositus, G6PD levels were found to be less than 10 per cent thus confirming diagnosis; the same enzymatic deficiency was identified in one of the siblings without a history of hematologic pathology and in a maternal cousin with a history of neonatal jaundice as well as two obliged carriers. Electrophoretical enzyme phenotype was similar to A variant in three affected males. Advantages of prevention and medical care possible with early diagnosis of G6PD deficiency are discussed.

Adolescent↗
PubMed1978

Galactosemia as a result of galactose-1-phosphate uridyltransferase deficiency.

This study was designed to determine the activity of galactose-1-phosphate uridyltransferase enzyme in a family (parents and eight children): four of these with clinical diagnosis of classical galactosemia. In two of them a complete transferase deficiency was found, thus confirming diagnosis; the other two, a pair of dizygotic twins, who since birth up to 11 years of age had been on a galactose free diet, showed enzymatic activity consistent with normal heterozygotes, one of them, and with normal homozygotes, the other. The parents and four brothers had the same enzyme activity levels an those found in heterozygotes for galactosemia. Early diagnosis is of utmost importance in classical galactosemia, and we emphasize this point because patients can be treated with dietotherapy and primary prevention is possible through genetic counseling.

Adolescent↗
PubMed1977

Nitrogen regulation of arginase in Neurospora crassa.

The final products of the arginine catabolism that can be utilized as a nitrogen source in Neurospora crassa are ammonium, glutamic acid, and glutamine. The effect of these compounds on arginase induction by arginine was studied. In wild-type strain 74-A, induction by arginine was almost completely repressed by glutamic acid plus ammonium, whereas ammonium or glutamic acid alone had only moderate effects. Arginine products of catabolism also repressed arginase induction. A mutant, ure-1, which lacks urease activity, hyperinduced its arginase with arginine as a nitrogen source. The addition of either ammonium or glutamine produced effects similar to those in the wild-type strain. The effect of ammonium on arginase induction is mediated through its conversion into glutamine. This was demonstrated in mutant am-1, which lacks L-glutamate dehydrogenase activity. In this mutant, the effect of glutamic acid was reduced, and, with ammonium, it was completely lost. The addition of glutamine or glutamic acid plus ammonium to this strain decreased by threefold the induction of arginase by arginine. Proline, a final product of arginine catabolism, competitively inhibited arginase activity. This effect and the repression of arginase by glutamine are examples of negative modulation of the first enzyme in a catabolic pathway by its final products.

Ammonia↗
PubMedDate not supplied

Erythrocyte superoxide dismutase activity in patients with malignant neoplasms.

Erythrocyte superoxide dismutase activity was determined in four groups of patients, two with hematologic neoplasms with and without therapy and two others with solid tumors also selected on the basis of therapy. Increased activities were found in the two groups where there was no treatment, whereas those under treatment showed normal levels. In addition, an inverse relationship (r = -0.25 p < 0.02) between superoxide dismutase activities and the time under therapy was observed.

Adult↗
PubMedDate not supplied

[Deficiency of glucose-6-phosphate dehydrogenase in a family].

The erytrocyte glucose-6-phosphate deshydrogenase (G6PD) identification and activity were determinated in all member of a family, which was selected because one of the sons showed the clinical signs of hemolitic anemia due to G6PD deficiency and this was confirmed by qualitative fluorescent test, enzyme activity quantification and electrophoretic runs. It was found that two clinically healthy brothers are G6PD deficients and that the mother and one sister are carriers of this enzimatyc defect of the A--variant. As an antecedent it was found that the propositus mother received chloramphenicol treatment for ten days during the first three months of pregnancy. The advantages of the opportune enzymatic studies, with the objective to avoid hemolitic crisis in those G6PD deficient persons, are commented.

Adolescent↗