Histology and histopathology Vol.15, nº 2 (2000)
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- PublicationOpen AccessNeonatal treatment with monosodium glutamate MSG structure of the TSH-immunoreactive pituitary cells(Murcia : F. Hernández, 2000) Miskowiak, B.; Partyka, M.Glutamic acid represents the most abundant stimulatory neurotransmitter in the central nervous system. Monosodium glutamate (MSC), subcutaneously administered to newborn rats in the perinatal period, induces lesions in 80 to 90% of the neurocytes of arcuate nuclei in the hypothalamus. These nuclei are the site of production of numerous stimulatory and inhibitory hormones including growth hormone releasing hormone (GHRH). The present studies were performed on male Wistar strain rats, subcutaneously injected on days 2, 4, 6, 8, and 10 of postnatal life with MSC at a dose of 4 mglg body weight. Eighteen-month-old rats were additionally treated with Ambinon. When the animals reached the ages of 6 or 12 months, their body weight, body length and weight of pituitary were determined. On parafrin sections, using imrnunohistochemical techniques, TSHimmunoreactive cells were detected and characterised by computerised image analysis. The results were subjected to statistical analysis using Student's t test. The rats which were perinatally treated with MSC and examined after 6 or 12 months of life were obese and shorter than control rats by 7% and 10% respectively. They also exhibited a reduction in the weight of the pituitary of 30% and 40% respectively in the two age groups. The proportion of TSH-immunoreactive cells in the pituitary remained unchanged and amounted to 4.5% in the 6-month-old and 5.4% in the 12-month-old rats respectively. The number of TSH-positive cells per mm 2 area remained unchanged. The area and circumference of the cells in the 12-month-old rats were reduced by 22% and 18%, respectively. Perinatal injury to hypophyseal arcuate nuclei induced by monosodium glutamate injection, was not associated with any significant alterations in pituitary structure, as defined by the proportion of pituitary volume occupied by TSH-immunoreactive cells.
- PublicationOpen AccessProlonged kallikrein inhibition does not affect the basal growth and secretory capacity of rat adrenal cortex, but enhances mineralo- and glucocorticoid response to ACTH and handling stress(Murcia : F. Hernández, 2000) Rebuffat, P.; Neri, G.; Bahgelioglu, M.; Malendowicz, L.K.; Nussdorfer, G.G.The effects on the pituitary-adrenocortical functions of the prolonged (7-day) blockade of endogenous bradykinin (BK) synthesis, obtained by the administration of the kallikrein inhibitor (K-I) cyclohexylacetyl-Phe-Arg-Ser-Val-Gln amide, were investigated in the rat. K-I treatment did not cause significant changes in the (i) body and adrenal weights; (ii) basal plasma levels of ACTH, aldosterone and corticosterone; and (iii) average volume of adrenocortical cells and their basal secretory capacity. Conversely, K-I administration induced a significant magnification of the in vivo mineralo- and glucocorticoid responses to the intraperitoneal (i.p.) bolus injection of ACTH. Moreover, K-I-treated rats, but not control ones, displayed a moderate and short-term adrenal secretory response to the mild stress evoked by the placebo i.p. injection. Collectively, these findings rule out the possibility that endogenous BK plays a relevant role in the control of adrenocortical function under basal conditions. However, they suggest that endogenous BK may be involved in quenching exceedingly high adrenocortical responses to ACTH and stresses.
- PublicationOpen AccessTenascin in the developing and adult human intestine(Murcia : F. Hernández, 2000) Belanger, I.; Beaulieu, J.F.The tenascins are a family of multifunctional extracellular matrix glycoproteins subject to complex spatial and temporal patterns of expression in the course of various organogenetic processes, namely those involving epithelial-mesenchymal interactions. In the intestine, the tenascins, in particular tenascin-C, have been found to be differentially expressed in the developing and adult small intestinal and colonic mucosa as well as in neoplasm. While tenascin-C emerges as a key player likely to be involved in intestinal mucosa development, maintenance and disease, its exact role in the regulation of fundamental intestinal cell function(s) such as proliferation, migration and tissue-specific gene expression remains however to be established.
- PublicationOpen AccessAbnormal distribution of CD45 isoforms expressed by CD4+ and CD8+ T cells in rheumatoid arthritis(Murcia : F. Hernández, 2000) Mamoune, A.; Durand, V.; Le Goff, P.; Pennec, Y.L.; Youinou, P.; Le Corre, R.CD45RO+ T cells are referred to as memory or helper-inducer while CD45RA+ T cells are regarded as naive or suppressor-inducer T cells. The former population predominates in the peripheral blood and even more in the synovial fluid of patients with rheumatoid arthritis, to the expense of the latter population. Within the CD45RB+ compartment, there appears to be more of the fully-differentiated than of the early-differentiated CD4+ T cells. In spite of the fact that these lymphocytes are close to undergoing apoptosis, this programmed cell death is inhibited in the rheumatoid synovium.
- PublicationOpen AccessA case study of ligation induced calcification in middle cerebral artery in rat(Murcia : F. Hernández, 2000) Tseng, M.T.; Chan, S.A.; Guo, S.Z.A 90 rnin ligation of the middle cerebral artery (MCA) followed by 72-hour reperfusion appeared to cause calcium deposition in vascular myocytes of the tunica media and thc pcrivascular tissue 01 the Sprague Dawley rat. The presence of small ovoid to large irregularly shaped intracellular opaque dcposits were demonstrated by light and electron microscopy. Using X-ray elemental analysis the chemical nature of the deposits was found to be calcium phosphate. The functional significance of this first demonstration of acute calcification following transient ligation of the rodent MCA invites further studies.