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Biomedical subjects

O A Mora

Publications and source records attributed to O A Mora.

29 records · Page 2Linked to original sources
PubMed1978

Electron microscopy of lamellated osmiophilic bodies in granular pneumocytes of the toad (Bufo icterus icterus) in an advanced stage of dehydration and after rehydration.

The effects of body dehydration on the ultrastructural pattern of lamellated osmiophilic bodies of granular pneumocytes of toads were investigated until almost complete absence of these bodies after 40 per cent body weight loss. The presence of lamellated osmiophilic bodies after rehydration would strongly indicate that water has a great influence upon the secretion of these structures.

Animals↗
PubMedDate not supplied

[Ultrastructural features of cardiac muscle fibers of albino rats during the pregnancy and puerperal cycle].

PURPOSE: In the present study we evaluated the morphology of left ventricular cardiomyocytes of albino rats during pregnancy and puerperium by means of transmission electron microscopy. METHODS: Once pregnancy was confirmed, 77 rats were randomly divided in two groups, respectively, gestation (G) and puerperium (P). The animals of the gestation group were divided into four subgroups, according to gestational age: 1st (G-A), 7th (G-B), 14th (G-C) and 21st (G-D) days of pregnancy. The group defined as puerperium was divided into three subgroups: 7th (P-A), 14th (P-B) and 21st (P-C) days of puerperium. In the end of each established period, the animals were sacrificed and fragments of the medium third of the left ventricle were resected and routinely prepared for electron microscopy analysis. RESULTS: The results obtained with transmission electron microscopy analysis revealed a gradative increase of the cardiomyocytes during pregnancy (increase of myofibrils, which are permeated by numerous mitochondria at the end of gestation). The blood capillary wall showed progressive thinning, with an increase of pynocytotic vesicles in endothelial cells, and intense sarcolemal folding at T-tubule level (capillary tunnels). In the puerperium group, there is a progressive regression in these alterations returning to pre-gestational level at the end of the puerperium cycle. These findings indicate the occurrence of hypertrophy of cardiomyocytes during pregnancy. CONCLUSION: The findings indicate the occurrence of hypertrophy of cardiomyocytes during pregnancy.

Adaptation, Psychological↗
PubMedDate not supplied

[Histomorphometric study of cardiomyocytes of the left ventricle of pregnant albino rats].

PURPOSE: In the present study we evaluated, by light microscopy, and throughout morphometry, whether hypertrophy of cardiac striated muscular fibers of left ventricular occur in albino rat, during pregnancy. METHODS: After maiting, 12 nuliparous rats were divided into four groups with three animals for each group. The female rats corresponding to each group were killed at 1st, 7th, 14th and 21st days of pregnancy. RESULTS: Observation, on light microscopy (H.E) had at one view, did not display any alterations during pregnancy. However, the morphometry revealed that nuclei of cardiomyocytes are augmented in volume at 14th day of pregnancy and statistically significant data show the hypertrophy. CONCLUSION: The obtained data show the existence of a dinamic and reversible process of ventricular remodelling in consequence of adaptation physiological alterations of the cardiovascular normal pregnancy.

Animals↗
PubMedDate not supplied

Histological development of the vomeronasal complex in the pre- and postnatal rat.

The vomeronasal complex of the rat was studied by means of different staining techniques and light microscopy between the 13th day of gestation and 42 days of postnatal life. The anlage of the vomeronasal organ in the 13-day-old embryo consisted of a cluster of cells proliferating from the olfactory placode towards the medial line. The vomeronasal organ was well developed by the end of gestation, showing the same ratio between receptor and receptor-free epithelium as in the adult animal. However, full development of the epithelia did not occur until the end of the second postnatal week. Glandular rudiments were observed within the vomeronasal area in 17-day-old fetuses, but the gland showed no sign of activity until the 7th day of postnatal life, when a slight PAS-positive reaction was observed in their cells' cytoplasm. This PAS-positive reaction intensified considerably during the second week and corresponded to the adult picture by the end of this time. The content of the vomeronasal glands contrasted with that of the glands flowing into the nasal fossa, which did not show any PAS-positive reaction but which stained positive for alcian blue. We also studied the evolution of the blood vessels such as the capsule of the complex. This capsule showed complete ossification by the beginning of the 3rd postnatal week, with the exception of certain regions which remained cartilaginous in the adult. Some capillaries were observed in the complex in 17-day-old fetuses, and by 20 days of gestation some of them could be observed penetrating the receptor epithelium. Subsequently, the vascularization of the complex became so profuse that one could consider the vomeronasal complex to consist of erectile tissue.

Animals↗
PubMedDate not supplied

[Ultrastructural aspects of the human uterine tube epithelium during menstrual cycle].

PURPOSE: The authors perform an electron microscopy analysis of the human uterine tube epithelium during the menstrual cycle. TYPE OF STUDY: Prospective, experimental. Site: São Paulo School of Medicine. PATIENTS: Four eumenorrheic multiparous patients, two in the proliferating stage, and two in the secreting stage of the cycle. INTERVENTIONS: PATIENTS were submitted to bilateral salpingectomy because they presented a high reproductive risk. MEASUREMENTS AND RESULTS: The authors evaluated ultrastructural aspects of the epithelium in the isthmus, ampulla, and infundibulum. Two types of cells were identified: ciliated and non-ciliated or secretory. Secretory cells have more marked ultrastructural changes than ciliated cells during the cycle. In the luteal stage, secretory cells present quite developed and dilated endoplasmatic reticulum and Golgi apparatus, and numerous electro-lucent vesicles. They also verified that during the second stage of the cycle, the secretory cells in the ampullar region seems to release part of its cytoplasm in the tube lumen. CONCLUSIONS: The ampullar region of the uterine tube suffers greater hormonal influences than the other regions. Morphological changes occurring in the ampullar might have their role to play in the nutrition of the egg cell during the time it remains inside it.

Adult↗