Histology and histopathology Vol.12, nº 3 (1997)
Ir a Estadísticas
Permanent URI for this collection
Browse
Recent Submissions
- PublicationOpen AccessThe role of carbohydrate residues in mammalian fertilization(Murcia : F. Hernández, 1997) Shalgi, R.; Raz, T.The fertilization process in mammals involves binding and fusion of free-swimming sperm and ovulated eggs. This review focuses on the role of carbohydrate residues in the process of sperm-egg interaction in mammals. The zona pellucida (ZP), the acellular glycoprotein coat surrounding the egg is highly glycosylated and posssess both Asn- (N-) linked and SerlThr- (O-)linked oligosaccharides, with an extreme structural heterogeneity between the different species. Different carbohydrates on ZP3, such as Galactose in a-linkage, N-acetylglucosamine in B-linkage, were suggested as the complementary sperm receptors, mediating the primary binding between the spermatozoon and the ZP. Several suggested complementary ZP3 binding proteins on the sperm are sp56, O-1,4-galactosyltransferase and p95. Some carbohydrate residues of the ZP undergo postfertilization modifications that might alter the sperm receptor, thus assisting in the establishment of the block to polyspermy. The studies summarized in this review imply a main role for the carbohydrate residues in the process of sperm egg interaction.
- PublicationOpen Accesslmmunocytochemical localization of the vacuolar H+-ATPase pump in the kidney(Murcia : F. Hernández, 1997) Bastani, B.In this article we review immunocytochemical localization studies using a monoclonal antibody raised against the 31 kD subunit of bovine H+- ATPase, and indirect immunofluorescent staining. In the proximal tubules there is intense H+-ATPase staining along the brush borders of S1 and S2, and linear subvillar invagination staining in SI, S2, and S3 segments. In the thick ascending limb of the loop of Henle there is a mild to moderate degree apical cytoplasmic vesicular staining. In dista1 convoluted tubule there is mild to moderate degree of H+-ATPase staining which is sharply delineated along the luminal plasma membrane. In the connecting tubule, the connecting tubule cells show mild to moderate luminal membrane and apical cytoplasmic vesicular staining, and the intercalated cells demonstrate prominent H+-ATPase staining which is polarized to either apical or basolateral pole or distributed diffusely throughout the cell. In the cortical collecting duct the principal cells show minimal or no staining while the intercalated cells show very bright H+-ATPase staining with 6 identifiable morphblogic subtypes based on polarization of the pump to apical or basolateral poles, and the degree of polarization (well polarized or poorly polarized). In the medullary collecting duct the principal cells show no staining and the intercalated cells show prominent H+- ATPase staining only in the apical pole. We also describe adaptive responses to different physiologic manipulations e.g. chronic oral acid loads, chronic respiratory acidosis, remnant kidney model, chronic desoxycorticosterone (DOCA) administration, and chronic potassium depletion diet. Moreover, we compare the immunocytochemical localization of the H+-ATPase pump of rabbit and kidneys.
- PublicationOpen AccessEffects of short-term treatment with CaCI2 or EDTA on the parathyroid glands in pregnant golden hamsters, with special reference to large vacuolar bodies(Murcia : F. Hernández, 1997) Emura, S.; Hayakawa, D.; chen, H.; Terasawa, K.; Tamada, A.; Isono, H.; Shoumura, S.The large vacuolar bodies in the parathyroid glands of pregnant golden hamsters after administration of CaC12 or EDTA were investigated. In the parathyroid glands of the pregnant animals 15 min after administration of CaC12, the mean serum calcium concentration was significantly high when compared to that of the control animals. In the parathyroid glands of the pregnant animals 15, 30 and 60 min after administration of EDTA, the mean serum calcium concentration was significantly low when compared to that of the control animais. In the parathyroid glands of the pregnant animals 15 min after administration of CaC12, the percentage area occupied by large vacuolar bodies was significantly increased when compared to that of the control animals. In the parathyroid glands of the pregnant animals 15 min after administration of EDTA, the percentage area occupied by large vacuolar bodies was significantly decreased when compared to that of the control animals.
- PublicationOpen AccessDevelopmental anatomy of the primary olfactory pathway in the opossum Monodelphis domestica(Murcia : F. Hernández, 1997) Chuah, M.I.; Tennent, R.; Teague, R.It has been shown in previous studies that the marsupial central nervous system is born at a relatively immature state. Although olfaction is thought to play a role in guiding the locomotion of the newborn, the cellular substrates on which this notion is based have not been systematically investigated. This review article surnmarises the anatomical development of the primary olfactory pathway in the postnatal Monodelphis. The olfactory epithelium and bulb appear morphologically immature at birth although some of the olfactory neurons are shown to express olfactory marker protein. The olfactory tissues subsequently undergo a rapid sequence of developmental events during the first two postnatal weeks. The evidence shows that the marsupial and eutherian olfactory system share a similar temporal sequence of developmental processes although the former proceeds at a lag time of about 10-14 days compared to that of mice (using the date of birth as a common reference point). Much physiological and behavioral studies remain to be done before we can be certain about the time at which full functionai maturity is attained in this system.
- PublicationOpen AccessUnorthodox myogenesis, possi ble developmental significance and implications for tissue histogenesis and regeneration(Murcia : F. Hernández, 1997) Cossu, G.During the last few years several reports have described the occurrence of skeletal myogenesis in cells derived from embryonic, fetal and perinatal tissues that usually do not contribute to skeletal muscle in the adult vertebrate body. After a brief description of current ideas on myogenic determination in higher vertebrates, three examples of this unorthodox myogenesis will be described: 1) the occurrence of myogenesis in chick epiblast cells, cultured in isolation in serum-free medium; 2) the presence of cells endowed with myogenic potential in the embryonic mouse neural tube; and 3) the occurrence of spontaneous or induced myogenesis in mesenchymal cells during fetal and postnatal life. A possible embryological basis for unorthodox myogenesis, in relation to gastrulation and morphogenetic fields, is then presented. It is also proposed that unorthodox myogenesis may represent a compensatory mechanism for higher vertebrates that have lost much of the regeneration potential of lower vertebrates.