Histology and histopathology Vol.14, nº 4 (1999)
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- PublicationOpen AccessSize and degeneration increase in herring bodies during aging in hamsters(Murcia : F. Hernández, 1999) Navarro, A.; Tolivia, J.; Alvarez-Uría, M.The hypothalamo-neurohypophysial tract of young, adult and aged male hamsters was studied at lateral and ventral regions of hypothalamus by means of electron microscopy. Neurosecretory swelling axons (Herring bodies) were usually found as classically described containing abundant neurosecretory granules, mitochondria, few microtubules and profiles of smooth endoplasmic reticulum in al1 groups of age. However, in aged hamsters, starting at 18-month-old subjects, we observed that the size of some neurosecretory axons was highly increased. Autophagic and degenerative features were seen in the larger ones. These data could suggest abnormal axonal storage or axonal transport blocked during aging. The implications in the role of hypothalamus- neurohypophysial system during aging are discussed.
- PublicationOpen AccessQuantitative in situ hybridization for the evaluation of gene expression in asynchronous and synchronized cell cultures and in tissue sections(Murcia : F. Hernández, 1999) Barlati, S.; Zoppi, N.; Copeta, A.; Tavian, D.; De Petro, G.; Colombi, M.We describe an image analysis (IA) system that has been applied for the quantitative evaluation of mRNAs evidenced by in situ hybridization (ISH) with radiolabelled probes in cultured cells and in tissue sections. The ISH-IA method was used for the evaluation of cultured cell morphological parameters such as cell and nucleous area (CA and NA, respectively) in parallel with the levels of mRNAs detected as hybridization grains areas (GA). The evaluation of these parameters, together with the analysis of the levels of mRNAs (c-jun, cyclin A) specific for given cell cycle phases (i.e. G1 and S/G2), allowed the identification, in asynchronous cultures of human skin fibroblasts, of cells in G1 and SlG2 phases. The mRNA levels measured by ISH-AI were comparable with those detected by RT-PCR. This method was also applied for the analysis of fibronectin (FN) gene expression in control skin fibroblasts in relationship with the different phases of the cell cycle and in comparison with a tumor cell line (Sk-Hepl), heterogeneous either for morphometric parameters or for the levels of this transcript. Finally, the ISH-AI was applied for the semiquantitative evaluation of the expression, localization and alternative splicing pattern of FN mRNA in normal liver and in hepatocellular carcinoma (HCC) tissue sections.
- PublicationOpen AccessEffects of neurotensin and bombesin on the secretory and proliferative activity of regenerating rat adrenal cortex(Murcia : F. Hernández, 1999) Hochol, A.; Markowska, A.; Meneghelli, V.; Jedrzejczak, N.; Majchrzak, M.; Nowak, M.; Nussdorfer, G.G.; Malendowicz, L.K.Neurotensin (NT) and bombesin (BM)-like peptides are known to be involved in the regulation of the rat hypothalamo-pituitary-adrenal axis. By using selective NT- and BM-receptor antagonists (NT-A and BM-A, respectively) we investigated whether endogenous NT and BM-like peptides play a role in the control of rat adrenal secretion and growth during enucleation-induced regeneration. At day 5 of regeneration, NT-A did not affect the plasma concentrations of aldosterone (PAC) and corticosterone (PBC), but at day 8, it raised both PAC and PBC over the respective baseline value; the simultaneous administration of NT abolished this effect of NT-A. BMA did not alter PAC and PBC at day 5 of regeneration, while at day 8 it enhanced PBC, an effect reversed by BM. NT-A did not alter mitotic index, and BM-A lowered it at both day 5 and day 8 of regeneration, an effect suppressed by the simultaneous administration of BM. Collectively, these findings allow us to draw the following conclusions: 1) endogenous NT and BM-like peptides influence adrenocortical regeneration in rats; 2) NT exerts a tonic inhibitory action on both aldosterone and corticosterone secretion, without affecting cellproliferation rate; and 3) BM-like peptides exert a tonic suppressive effect on corticosterone production, coupled with a clear-cut stimulating effect on cell proliferation.
- PublicationOpen AccessHeart mitochondria in rats submitted to chronic hypoxia(Murcia : F. Hernández, 1999) Cervós-Navarro, J.; Kunas, R.Ch.; Sampaolo, S.; Mansmann, U.The effect of prolonged exposure to normobaric hypoxia on the mitochondria of myocard of rats exposed for several weeks to 8 and 7% O2 has been morphometrically evaluated. Twelve male Wistar rats housed in Nalgene cages (2 per cage) with a batch of six cages placed in plexiglass chambers were maintained in air/N2 mixtures containing different concentrations of 02. Six animals kept in similar cages under normoxia served as controls. When at day 60 the FIOZ was reduced to 8%, the weight increase stagnated and after the 81st test day, on which the hypoxic animals were subdivided into 8% and 7% groups the weight curve showed a decrease in the mean body weight for both groups. The arrest and the following loss of weight beyond the 85th day may be interpreted as the expression of a limit reached in the compensation capacity. In the 8%-group the shape of the mitochondria varied more markedly often with budding and furrowing of the surface. In the 7%-group bizarre shapes and wide variations in size with a decided shift towards larger mitochondria were noteworthy. While rats kept under 8% oxygen exhibited a numerical increase in myocardial mitochondria compared to controls, the mitochondria of the 7%-group were numerically reduced. The results suggest that hypoxia of 8% oxygen is compensatable, if only to some extent, by an increasing surface of mitochondrial membranes, and that further reduction of oxygen causes compensation mechanisms to fail as seen by the severe alterations of the mitochondrial population of the cardiomyocyte in the 7%-group.
- PublicationOpen AccessRegulation mechanisms for the heterodimeric transcription factor, PEBP2lCBF(Murcia : F. Hernández, 1999) Bae, S.C.; Ito, Y.Members of the new PEBP2 (Polyomavirus Enhancer Binding Protein 2) family of heterodimeric transcriptional regulatory protein are composed of two subunits, a and B. One of the genes encoding the a subunit, AMLlIPEBP2aB, was identified at the breakpoints of various chromosome translocations, including t(8;21) and t(12;21) associated with acute myeloid leukemia and acute lymphoblastic leukemia, respectively. The gene encoding the B subunit (PEBP2flCBFB) was also shown to be the target of the inversion of chromosome 16, another chromosomal anomaly associated with acute myeloid leukemia. Targeted disruption of either the AmlllPebp2aB or PebpZflICbfb gene resulted in strikingly similar phenotypes such as lack of definitive hematopoiesis of the fetal liver and accompanying hemorrhage of the central nervous system. These observations suggest that both a and l3 subunits of PEBP2 are indispensable for its in vivo function. However, the heterodimerization of the a and B subunit does not seem to occur readily suggesting that their capacity to associate might be an important rate limiting step in PEBP2 site-dependent transcription regulation. In this review, we concentrate on the possible regulatory mechanisms of PEBP2 activity in relation to leukemogenesis.