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Biomedical subjects

B Ibarra

Publications and source records attributed to B Ibarra.

At least 73 records · Page 4Linked to original sources
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

De novo partial trisomy of chromosome 18(pter yields q11:). Some observations on the phenotype mapping of chromosome 18 imbalances.

An infant with a partial trisomy 18(pter yields q11:) is described. The patient's phenotype consists of many features of complete trisomy 18. The findings are compared with those from similar cases reported in the literature permitting to conclude that 18q121-q122 segment is the "critical" zone which when trisomic, causes the severe stigmata (inner organ malformations and early death) of the complete trisomy 18.

Child, Preschool↗
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↗
PubMedDate not supplied

Computed tomography in supratentorial hemangioblastoma.

Supratentorial hemangioblastomas are rare. A 28-yr-old man with a solid tumor in the left temporal region is described. There was neither meningeal connection nor associated polycythemia or Von Hippel-Lindau disease. Contrast enhanced computerized tomography showed a hyperdense, homogeneous lesion and cerebral angiography demonstrated a nodular tumor blush. The microscopic appearance of the lesion is described with a review of previously reported cases.

Adult↗
PubMedDate not supplied

Post-radiation cranial malignant fibrous histiocytoma studied by CT.

A 37-year-old woman presented with a proven case of malignant fibrous histiocytoma of the skull. This is thought to be a rare complication of post-radiation to a chromophobe adenoma which was treated by radiotherapy nine years previously. The radiation dose given to the sella region after the removal of the chromophobe adenoma was 4500 cGy.

Adenoma, Chromophobe↗
PubMedDate not supplied

The C677T polymorphism of the methylenetetrahydrofolate reductase gene in Mexican mestizo neural-tube defect parents, control mestizo and native populations.

The C677T mutation of the methylenetetrahydrofolate reductase (MTHFR) gene, associated with the thermolabile form of the enzyme, has reportedly been found to be increased in neural-tube defects (NTD), though this association is still unclear. A group of 107 mestizo parents of NTD children and five control populations: 101 mestizo (M), 50 Huichol (H), 38 Tarahumara (T), 21 Purepecha (P) and 20 Caucasian (C) individuals were typed for the MTHFR C677T variant by the PCR/RFLP (HinfI) method. Genotype frequencies were in agreement with the Hardy-Weinberg expectations in all six populations. Allele frequency (%) of the C677T variant was 45 in NTD, 44 in M, 56 in H, 36 in T, 57 in P, 35 in C. Pairwise inter-population comparisons of allele frequency disclosed a very similar distribution between NTD and M groups (exact test, P=0.92). Among controls, differences between M and individual native groups were NS (0.06<P<0.21), as it was between M and C (P=0.29). A high frequency of the variant was found in H (56%) and P (57%). A similar allele frequency in groups M and NTD does not support a causal relationship between NTD and parental MTHFR C677T genotypes. Thus, the C677T variant cannot be regarded as a major genetic risk factor for NTD in Mexican mestizo parents. Otherwise, C677T in Mexico is very frequent, especially in Huichol and Purepecha natives, as compared with other groups world wide.

DNA↗
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

[Molecular aspects of alpha dn beta thalassemias].

Thalassemia has been considered a recessive, autosomic, hereditary disease, characterized by microcytic, hypochromic, hemolytic anemia, which occurs as the consequence of a defect in the synthesis of the globin chains, the two most frequent types are thalassemias a and b, which in their most severe forms are known as Hydrops Fetalis and Major Thalassemia. The patients who bear thalassemia are concentrated to those places on earth where malaria is endemic, including the Mediterranean region, Northern Africa, The Middle East, India, China and Southern Asia. The simple Heterozygotic states in both types of thalassemia are more benign and may go unnoticed or confused with iron deficiency.

Base Sequence↗
PubMedDate not supplied

[Changes in hemoglobin in patients with hemolytic anemia].

Hb alterations studied throughout 2 years in 129 patients are reported, these patients had hemolytic anemia or the possibility of a hemoglobinopathy : 5 were heterozygotes to thalassemia b; 3 were compound-heterozygote of thalassemia a1 and thalassemia a2; 2 for thalassemia b and 2 for thalassemia b and Hb S; 2 homozygotes and 2 heterozygotes for Hb S; 2 was bearing unstable Hb and the other had Hereditary Persistence of Hb F. These results allow the conclusion that thalassemia is the Hb alteration which most frequently causes hemolytic anemia in our population and underscores the importance of the study of these pathologies in selected populations.

Anemia, Hemolytic↗
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↗
PubMedDate not supplied

Prolapsed lumbar disk: value of CT in diagnosis.

A group of 40 patients with symptoms of prolapsed lumbar disk, seven of which were recurrent after surgery, was studied by computed tomography. In all cases, the diagnosis was confirmed by myelography and posterior surgery. Computed tomography was performed after the disappearance of myelographic contrast medium. Positive herniated disk was shown by computed tomography in 88%. In postoperative cases, computed tomography after intravenous contrast enhancement favored the recognition of postoperative scar, rather than recurrent herniation. Computed tomography also facilitated the diagnosis of spondylotic lesions, which may accompany herniated disks. Computed tomography should reduce the need for myelography, which is reserved for cases with doubtful computed tomographic findings.

Diagnosis, Differential↗