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Biomedical subjects

E Valdez

Publications and source records attributed to E Valdez.

14 recordsLinked to original sources
PubMed2000

Uniparental disomy in steroid 5alpha-reductase 2 deficiency.

Steroid 5alpha-reductase 2 deficiency is an autosomal recessive form of male pseudohermaphroditism caused by mutations in the SRD5A2 gene. In this study, we performed DNA analyses in two unrelated subjects bearing the enzyme deficiency and found differences in the mode of transmission for the disease. The data showed that in both families the fathers were carriers for an E197D mutation, whereas the mothers were carriers for a P212R mutation. Patient 1 was identified as compound heterozygote because he had both alterations (E197D/P212R). On the contrary, patient 2 was found to be homozygous, but only for the paternal mutation. Because this finding could not be explained on the basis ofnonpaternity or a chromosomal abnormality, the presence of uniparental disomy was suggested. The reduction to homozygosity for the E197D mutation, as confirmed by restriction analysis, supported this view. The results of our study give evidence of the first case of 5alpha-reductase deficiency resulting from uniparental disomy and also disclose an alternate mechanism whereby this enzymatic disorder can derive from a single parent.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1999

HLA characterization in adult asymptomatic cyst passers of Entamoeba histolytica/E. dispar.

The present work aimed at studying the possible association of HLA antigens with Entamoeba histolytica/E. dispar asymptomatic infection in a Mexican mestizo population. A case-control design was selected for evaluation of the role of genetic markers in parasite infection. For this purpose the HLA-A, HLA-B, and HLA-DR profiles of a population of asymptomatic E. histolytica/E. dispar adult cyst passers (cases) and a corresponding nonparasitized adult group (controls) followed for 12 months were identified. Entamoeba species were identified through zymodeme patterns and/or amplification of species-specific DNA sequences. A healthy, nonparasitized group of individuals was included as a control. Our results show that apparently, no specific HLA marker is associated with the asymptomatic cyst passers' condition. These findings have to be added to previous results in which, in contrast to a demonstrated association between HLA-DR3 and amebic liver abscess in Mexican mestizo adults and infants, no significant association with amebic rectocolitis was found.

Animals↗
PubMed1995

Sperm migration through the female genital tract of the New World monkey Cebus apella.

This study was designed to characterize sperm migration in the female genital tract of Cebus apella. Forty-eight cycles of eighteen females mated during the periovulatory period were studied. Eggs were searched for and spermatozoa were counted in segmental flushings of the genital tract performed in situ 1-7 h, 19-31 h, or 45-56 h after coitus. Of 14 eggs recovered, 8 were fertilized, thus assuring a reasonable normality of prefertilization phenomena in both males and females. A downward gradient of several orders of magnitude in sperm numbers was recognized from cervix to ampulla, particularly over the first interval. The population in the cervix and uterus decreased progressively between the first and last interval. Spermatozoa were recovered from the ampulla as early as 1 h after mating. Different trends were observed in the isthmus and ampulla. From the first to the last interval, sperm numbers decreased in the ampulla, but not in the isthmus. The number of spermatozoa recovered from the ampulla of the ovulatory side 1-31 h postcoitum was higher in postovulatory than in preovulatory monkeys, while in the nonovulatory side, recovery was similar in the two conditions. This findings suggests that the passage of spermatozoa up to the site of fertilization is under local control and is synchronized with ovulation. The pattern of sperm migration that emerges from these data bears similarities to the pattern in nonprimate species as well as distinctive features. A unique feature in common with the pattern in human is the early establishment of a fairly abundant and persistent sperm population in the ampulla.

Animals↗
PubMed1994

[Vaccination coverage of 2-year-old children in Geneva].

OBJECTIVE: To measure the immunization uptake among 2 year-old children living in Geneva. METHODS: Review of the vaccination cards, systematically checked because of the compulsory vaccination against diphtheria, during the year in 1991. RESULTS: 3937 immunization cards were reviewed, ie. 93.6% of the children in the given age group. Immunization uptake rates were, for diphtheria and tetanus (3 doses) 96.8%; pertussis (3 doses) 96.1%; poliomyelitis (3 doses) 96.6%. For measles, mumps and rubella vaccine (MMR) (1 dose), 78.4%. For the Haemophilus influenzae b vaccine, recently introduced: 68.5%. The uptake rate for MMR was lower among children of swiss origin (75.5%) than among children of other nationalities (84.6%, p < 0.0001). The highest rates were found among children coming from southern Europe and Latin America. CONCLUSIONS: From the point of view of the community risk, immunization uptake rates for diphtheria, tetanus, pertussis and poliomyelitis can be considered satisfactory. For MMR vaccine, the rate was higher than 2 years earlier, but still insufficient, compared to the level which could block the transmission of the target diseases in the population. The persistence of such a low rate of immunization uptake will not prevent the occurrence of epidemics in the population.

Child, Preschool↗
PubMed1989

In vitro cytoadherence of Plasmodium falciparum-infected erythrocytes to melanoma cells: factors affecting adhesion.

A reproducible and standardized assay for measuring the cytoadherence of knobby Plasmodium falciparum-infected red cells to amelanotic melanoma cells was developed. Adhesion was dependent on temperature, haematocrit, and parasitaemia. Addition of EDTA to the binding medium reduced adhesion. Removal of protease-sensitive molecules on the surface of the infected cell abolished cytoadherence, whereas removal of carbohydrate residues by treatment of cells with neuraminidase or galactosidase promoted adhesion. Calcium, magnesium, fibrinogen or fibronectin in the medium had no effect on adhesion nor was there any enhancement of adhesion by pre-loading infected cells with calcium. Serum was essential for good adhesion. Adhesion was species specific for target cells; human endothelial or amelanotic melanoma cells were suitable target cells whereas bovine cells were not. The amelanotic melanoma cell could be formalin-fixed and still retain its adhesion properties. The binding properties of formalin-fixed amelanotic melanoma cells were not identical to those of endothelial or unfixed target cells.

Animals↗
PubMed1985

Low cost, microprocessor-based system for flow evaluation in a hydraulic model using the dilution method.

An Automatic Dye Dilution Processor (ADP) based on a microprocessor is applied to a hydraulic model to process on-line dilution curves, using saline or thermodilution methods. A low cost, F8 microcomputer with minimum parts configuration was used in an Automatic Dilution Processor (ADP) system. Software allows an operator to select methods, amount of indicator to be injected, cell calibration constant, and temperature step. Care has been taken in the curve data processing, to avoid errors when recirculation occurs. The system is used, together with an open hydraulic model, for flow measurement demonstration, and the estimation of cell calibration constant.

Calibration↗
PubMed1981

Saline and thermal dilution flow measurements: evaluation by means of an open hydraulic model.

A simple open hydraulic model was constructed with the main objective of making comparative evaluations of flow rate measurements, with saline and thermal dilution. In the range of 0.5 to 3.5 l/min, it was found that saline indicator gave a slight underestimation (in the order of 2%) while the thermal indicator showed a minor overestimation of approximately 1%. These values wee taken from the regression equations F (saline) = 0.945 F (real) + 0.0351 and F (thermo) = 1.020 F (real) - 0.0144, both in l/min. Correlations were higher than 0.99 in the two cases. Considering the overall error range, the thermodilution produced a value approximately twice that of saline (-21 to 25% versus -12 to +11%). However, this is not necessarily extendable to living organisms. The model was found useful for test and calibration of detecting cells and for teaching purposes.

Mathematics↗
PubMedDate not supplied

[Biochemical and endocrine heterogeneity in the complete form of testicular feminization syndrome].

A familial variant of male pseudohermaphroditism different from the classical form of the complete testicular feminization syndrome was studied. The three affected 46, XY sibling (16,18 and 20 years old) exhibited female phenotype identical to that of a 17 years old patient with the classical form, included as a control. The major endocrine and biochemical differences observed in this family, as compared with the classical form, includes: a. Markedly elevated serum levels of LH and FSH; b. Non-elevated serum testosterone levels; c. Poor testicular hCG responsiveness; d. Abnormally elevated baseline and hCG-stimulated androstenedione: testosterone ratio; e. Slight pituitary responsiveness to androgens; f. presence of residual androgen uptake by cultured fibroblasts derived from genital skin. These differences were more evident in the two older patients. All subjects presented a lack of nitrogen retention following testosterone administration. These results were interpreted as demonstrating a testicular impairment of testosterone biosynthesis in the older subjects of this family, which resulted in an unusual gonadotropin profile. The altered androstenedione: testosterone ratio suggests a secondary partially decreased activity of testicular 17-hidroxysteroid dehydrogenase, as demonstrated in TFM mice and rats. The overall data indicate an age-dependent variability in the expression of androgen insensitivity in this family, thus demonstrating the wide biochemical heterogeneity of the androgen resistant syndromes.

Adolescent↗