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Biomedical subjects

O Frota-Pessoa

Publications and source records attributed to O Frota-Pessoa.

At least 37 records · Page 2Linked to original sources
PubMed1979

H-Y antigen in Swyer syndrome and the genetics of XY gonadal dysgenesis.

The H-Y antigen is a plasma membrane antigen involved in the organogenesis of the mammalian testis. Its expression on human cells is determined by a Y-linked gene. Phenotypic females affected by 46,XY gonadal dysgenesis (Swyer's syndrome) can be either H-Y-positive or H-Y-negative. In this paper we report H-Y antigen and endocrine studies in a sibship with three affected sisters. Immunological studies were performed on two of the patients, and a clearly positive expression was detected in both cases. Endocrine studies consisted in the investigation of the hypothalamic-pituitary-gonadal axis, which revealed that gonadal hormone insufficiency is the only endocrine abnormality associated with the syndrome. A new genetic interpretation and calssification of XY gonadal dysgenesis is proposed.

Adolescent↗
PubMed1979

Atrichia, abnormal EEG, epilepsy and mental retardation in two sisters.

Two daughters of a nonconsanguineous couple are described. Both present mental retardation, epileptic seizures, congenital atrichia, histologically anomalous skin and abnormal EEG pattern. From a discussion of the literature on atrichia, the forms without involvement of teeth, nails and hidrosis, among which recessive inheritance prevails, are distinguished from each other. None of them coincide with the syndrome described here.

Abnormalities, Multiple↗
PubMed1978

Risks of manifestation of Huntington chorea.

A methodology allowing the estimate of risks heterozygosity and manifestation of Huntington's chorea (HC) within preestablished periods for individuals of any age was developed. For this, the procedure was the following: 1. The variables which could influence the distribution of age frequencies were studied. 2. The error due to the exclusion of the heterozygotes dying before the manifestation of the disease from the distribution of Wendt et al. (1959) of affected persons was corrected separately for each sex. 3. The frequency of non-affected heterozygotes in each age group was calculated separately for each sex, from the corrected distribution. From those data estimates of the following parameters could be reached: a) the probability of heterozygosity for consultants of any age; b) the risks of manifestation for the gene in a given individual within a determined period, taking into account his probability of heterozygosity and survival. 4. The risks of manifestation were tabulated for making easier their use in concrete cases. Simplified tables with approximate risks are also presented for the more common cases in genetic counseling. 5. The methodology presented allows a discrimination between the probability of heterozygostiy and the risk of manifestation. This makes possible the estimate of risks of becoming affected, taking into account not only the age of the consultant at the moment, but also the period of time starting with the consultation, to which the risk applies. This is essential for adequate genetic counseling.

Age Factors↗
PubMed1977

Myotonic dystrophy, syringomyelia, and 2/13 translocation in the same family.

The present report describes a sibship with 2 individuals affected by myotonic dystrophy and a third with syringomyelia. The mother was affected by myotonic dystrophy. A balanced 2/13 translocation was detected in the individual with syringomyelia, in one affected by myotonic dystrophy and in their clinically normal father. The association between the phenotypic anomalies and the chromosome alteration is coincidental.

Chromosome Aberrations↗
PubMed1977

The human Y chromosome: its routine identification and variability.

Different criteria for identifying the human Y chromosome using only conventional staining techniques were evaluated and a procedure based on three of them was developed. It leads to correct identification in 93% of cells even without resorting to differences in size between the Y and the other G chromosomes. The variability in size of the human Y chromosome was assessed in a random group of White men. It was found to be significantly greater than that of all other chromosomes in the karyotype when the comparisons were made in such a way as to avoid the size-dependent component of variation.

Analysis of Variance↗
PubMed1977

A search on karyotypic mosaicism in mongoloid patients and their parents.

The frequency of chromosomal mosaicism among patients with clinical diagnosis of mongolism was determined. Among 50 patients with at least 32 cells studied, 2 (or 4%) were found to be mosaics of the 46/47, +G type. Among 350 patients with at least 5 cells studied, 2 (or 0.57%) 46/47, +G mosaic cases were detected. Taking in account the probability of detecting mosaicism when 5 cells are analysed, a frequency of 0.58% of mosaic cases was estimated for this sample. The mosaic patients were submitted to repeated cytogenetic examination. One of these cases showed significant differences between the frequencies of normal cells, but a linear regression analysis showed that there was no correlation between the frequency of these cells and the patient's age. Clinically, the mosaic patients showed no consistent differences in the severity of the syndrome when compared to mongoloids without mosaicism. A frequency of 16 translocation cases (4%) was found in the total number of mongoloid patients studied. In a sample of 190 parents of regular trisomy-21 children no mosaicism was found in the blood. Also no significant differences were observed between the frequencies of aneuploid, hyperdiploid or hypodiploid cells and those obtained by other authors in the general population.

Adolescent↗
PubMed1976

A study of chromosomes of schistosomiasis patients under oxaminiquine (UK 4271) treatment.

Blood samples from 24 patients infested with Schistosoma mansoni were drawn immediately before and 2 days after the administration of a single therapeutic dose of 12-15 mg/kg oral oxaminiquine. Two-day lymphocyte cultures were obtained and about 100 mitoses from each blood sample were analyzed for chromosome aberrations. No significant differences were observed between the "before" and "after" cultures in the frequencies of aberrations resulting from spindle, chromatidic, or chromosome events. It is concluded that there is no reason to fear harmful effects on the chromosomes of patients from treatment with oxaminiquine.

Chromatids↗
PubMed1976

Creatine-phosphokinase (CPK) activity in relatives of patients with X-linked muscular dystrophies: a Brazilian study.

Serum CPK was measured in 135 families with Duchenne muscular dystrophy (DMD) and 19 with the Becker type (BMD). Increased CPK was found in 62% of the carriers of DMD and 62.5% of the BMD. Two certain carries of DMD and one of their daughters showed clinical signs of myopathy. Three studied DMD pregnant carriers suggest that there is a decrease in CPK levels around the 4th-5th months of gestation. In genetic counselling of suspected carriers the CPK activity of their normal daughters should always be considered. Our data suggest strongly that CPK activity decreases in carriers with increasing age.

Age Factors↗