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Biomedical subjects

J G Fernández

Publications and source records attributed to J G Fernández.

12 recordsLinked to original sources

A new successful therapy for fetal chylothorax by intrapleural injection of maternal blood.

We present two cases of fetal chylothorax and hydrops diagnosed at 20 weeks' gestation, both of which underwent successful intrauterine treatment. In Case 1, a transient, near total resolution began 2 weeks after an iatrogenic hemothorax following a second thoracocentesis performed at 24 + 6 weeks. Because of pleural fluid reaccumulation, a Cesarean section was performed at 36 weeks. The 3805-g female neonate was admitted to neonatal intensive care but was discharged 50 days later in a healthy condition. In Case 2, resolution occurred after a third thoracocentesis and a second pleural injection of maternal blood, performed at 26 weeks. A 2660-g female neonate was delivered vaginally at 38 weeks. The infant remained asymptomatic and was discharged aged 4 days. Our experience suggests a possible useful role of intrapleural blood injection for the treatment of fetal chylothorax.

Adult↗

Scanning electron microscopy of the wild boar and pig lingual papillae.

Lingual papillae of wild boar and pig were studied by means of scanning electron microscopy (SEM). Vallate papillae appear with the typical circumvallate morphology. Their papillary bodies show conical or fungiform-like and spicule-like pseudopapillae in both animals. Taste pores were seen in the papillary grooves. Microplicae or pits are visible at high magnification. In pig and wild boar similar foliate papillae were observed. Pig has less but wider leaves than wild boar. Taste pores on papillary walls were viewed. At high magnification microplicae were seen. Morphologically, fungiform papillae correspond with their denomination. Taste pores open onto the upper surface and they are easily identifiable by SEM. The rostral and lateral regions contain the major number of fungiform papillae. The lateral papillae of wild boar and pig show a high number of pores per papilla. These regions must be considered important in taste sensitivity. Lateral papillae in both animals could provide a source of taste buds for study. In both animals the fungiform papillary epithelium showed a pitted appearance as a consequence of keratinization by food environmental stress. The filiform papillae can be both simple and compound (with body and hairs). Large conical papillae are located caudally and curved in the same direction. Filiform and conical papillae have a function in food mastication, handling and deglutition.

Animals↗

A study of the chick thymus microenvironment during development: analysis by monoclonal antibodies against thymic epithelium.

The process of T-lymphocyte differentiation within the thymus involves a series of molecular interactions. In this work we have carried out an analysis of the chick thymus microenvironment in order to evaluate its heterogeneity during development. We have produced 11 monoclonal antibodies whose staining patterns detected by the immunoperoxidase technique allowed us to divide them into five groups. A first group (E19-E2, P0-E5, and P15-T1) binds to thymic medullary stroma showing a reticular pattern on medullary epithelial cells and whose significance would be related to thymic stromal secretion. The second group of monoclonal antibodies (P15-T3) stains thymic corpuscles of 10- and 15-day chicks. The third group of antibodies includes P0-E1, P0-E3, P5-A6, and P15-T2 whose staining pattern is both medullary and cortical. The fourth group (P10-HB1 and P10-HB2) binds to thymic stromal and cortical thymocytes, and the fifth group (P5-A1) is characterized by the staining of medullary vessels of 5-day chicks. These five groups of monoclonal antibodies corroborate the existence of an antigenic diversity of the chick thymus microenvironment. Their possible relationships with T-cell differentiation and stromal-thymocyte interactions are discussed.

Animals↗

Fungiform papillae of the pig and the wild boar analyzed by scanning electron microscopy.

Fungiform papillae of wild boar and pig were studied by scanning electron microscopy (SEM). Four regions were defined on the tongue: rostral, medial and caudal thirds and lateral sides. Morphologically the fungiform papillae correspond with their denomination. Rostral and lateral tongue regions presented the largest average number of fungiform papillae. Taste pores opened onto the upper surface of the papillae and were easily identifiable by SEM. The total number of fungiform taste pores from both animals was the highest reported in the literature. The lateral papillae of wild boar and pig contained the largest average number of pores per papilla. This region must be important in taste sensitivity. Lateral and rostral papillae from both animals can provide a source of taste buds for study since each fungiform papilla presents numerous taste buds and these papillae are very abundant.

Animals↗

Trichloroethylene exposure. Biological monitoring by breath and urine analyses.

A mathematical model developed previously has been used to study some aspects of biological monitoring of exposure to trichloroethylene (TRI) by the analysis of this solvent in alveolar air or of its metabolites, trichloroethanol (TCE) and trichloroacetic acid (TCA), in urine. Assuming that a biological control must be representative of the time-weighted average concentration (TWA), it was found that sampling for TRI and TCE analyses must be carried out the morning after the exposure being considered. On the other hand, for a TCA analysis, the timing of urine sampling is not a determinant factor. Theortical limit concentrations have been set up for these biological indicators, but it is shown that their application must be restricted to exposures which are quantitatively reproducible from one day to the next. In all other cases, it appears that this monitoring method can lead to errors in the estimated exposure concentrations. A tentative method of biological monitoring is therefore proposed. It is based on the analysis of TCE in the urine or TRI in the alveolar air before and after the exposure being monitored. TCA is not considered to be sensitive enough to variations in the inspired concentration to be used as an indicator of a single exposure risk.

Environmental Exposure↗

Trichloroethylene exposure. Simulation of uptake, excretion, and metabolism using a mathematical model.

The absorption, distribution, and excretion of trichloroethylene, as well as the kinetics of formation and elimination of trichloroethanol (TCE) and trichloroacetic acid (TCA) were simulated by a mathematical model. The results of this model have been satisfactorily compared with those obtained experimentally from pulmonary elimination of the solvent and from urinary excretion of the metabolites. The model permitted a study of the distribution of the solvent in the different tissues of the organism as well as an evaluation of the body burden of TCE and TCA. The influence of the duration and repetition of the exposure on the urinary eliminations of TCE and TCA was studied, and showed that the excretion of the first metabolite represents the most recent exposure while that of the second is related to the average exposure of the preceding days. The study of the pulmonary elimination of trichloroethylene during single or repeated exposures showed a linear relationship between the alveolar concentration of the solvent approximately 15 hours after the end of the exposure and the quantity of trichloroethylene accumulated in the fatty tissues.

Environmental Exposure↗

Simultaneous determination of toluene and xylene metabolites in urine by gas chromatography.

A gas chromatographic method for simultaneous determination of hippuric and o-, m-, and p-methylhippuric acids (metabolites of toluene and xylene) in urine is described. The analytical procedure is based on the extraction of the aromatic metabolites with ethyl acetate containing the internal standard and on a methylation with 3-methyl-1-p-tolyltriazene. With this method, which does not require much time and handling, the different acids can be satisfactorily determined with high sensitivity and specificity. A statistical study shows a good reproducibility for the determination of hippuric and o-, m-, and p-methylhippuric acids. The coefficient of variation for 10 determinations in all cases was less than 5%.

Chromatography, Gas↗

Direct evidence of luteal insufficiency in women with habitual abortion.

Plasma levels of progesterone were measured during the luteal phase in 10 of 15 women with clinical histories of at least three spontaneous abortions in the last three gestations, and in 15 healthy nonpregnant women during the same phase of the ovarian cycle. Progesterone values found in the women with habitual abortion were lower (P less than 0.05-0.005) than in the nonpregnant group almost throughout the period of observation. The habitually aborting women who became pregnant again aborted between the seventh and 12th weeks. Their progesterone concentrations were less than 6 ng/ml, 48-72 hours before vaginal bleeding or abortion. These values were compared with those found during the first 12 weeks in normal pregnancy (P less than 0.001). The results suggest a useful method of evaluating the treatment of habitual abortion.

Abortion, Habitual↗