Histology and histopathology Vol.14, nº 2 (1999)
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- PublicationOpen AccessRi bonuclease-gold labels proteoglycancontaining cytoplasmic granules and ribonucleic acid-containing organelles - A survey(Murcia : F. Hernández, 1999) Dvorak, A. M.; Morgan, E.S.An enzyme-affinity-gold method to detect RNA in routinely prepared ultrastructural samples is based on the affinity of the gold-coupled enzyme, ribonuclease, for its substrate, RNA. High concentrations of a known inhibitor of RNase, heparin, are uniquely located in human mast cell granules. Specific labeling for the presence of heparin in these structures was determined using the RNase-gold (R-G) reagent based on the RNase inhibitor property of heparin. This property was used to probe for the presence of proteoglycans (PG) known to be present in a wide variety of ultrastructural samples, none of which contain heparin. In addition to known subcellular sites of RNA, the R-G reagent was shown to bind to PG-rich cytoplasmic granules in a wide variety of leukocytes and secretory cells of epithelial, endocrine, and neuroendocrine origin. This newly recognized property was used to image the changing distribution of labeled PGs during cellular maturation, secretion, and recovery from secretion of secretory cells in vivo, ex vivo, in vitro and in isolated, biochemically defined guinea pig basophil granule preparations.
- PublicationOpen AccessInduction of NADPH diaphoraselnitric oxide synthase in the spinal cord motor neurons of rats following a single and multiple non-penetrative blasts(Murcia : F. Hernández, 1999) Kaur, C.; Singh, J.; Moochhala, S.; Lim, M.K.; Lu, J.; Ling, E. A.The present study has demonstrated the induction of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) reactivity and nitric oxide synthase-like immunoreactivity (NOS-LI) in the ventral horn motoneurons of the spinal cord in rats subjected to a single or multiple underground, or a single surface blast. Both enzyme activities were first detected in some motoneurons in laminae V111 and IX of Rexed, 3 hours after the blast. Some NADPH-d and NOS-L1 positive neurons were also distributed in laminae V1 and V11. The number and intensity of the labelled cells appeared to increase progressively, peaking at 2-3 days after the blast but were drastically reduced thereafter, so that at 7 days after the blast only a few positive neurons were observed. In rats killed at 2 weeks and in longer surviving intervals, i.e. up to 1 month, NADPH-d/NOS reactivity in the ventral horn motor neurons had diminished. The functional significance of the transient expression of neuronal NADPH-d/NOS after the blasts remains uncertain, although from a speculative point of view, the induction of these enzymes probably would reflect an increased production of nitric oxide (NO). In view of the lack of atrophic changes in most, if not all, of motor neurons, it is suggested that the increased levels of NO production after the blast injury may be involved in a neuroprotective function.
- PublicationOpen AccessPersistence of Cajal-Retzius cells in the adult human cerebral cortex. An immunohistochemical study(Murcia : F. Hernández, 1999) Martí, R.; Gutierrez, A. ,; Peñafiel, A.; Marin-Padilla, M.; De la Calle, A.The presence of Cajal-Retzius cells in the adult human prefrontal and visual cortices has been demonstrated with calcium binding protein immunocytochemistry and NADPH-diaphorase histochemistry. These cells expressed parvalbumin, calbindin and calretinin calcium binding proteins and displayed NADPH-diaphorase enzyme activity. The three basic morphological profiles-horizontal, pyriform and multipolar-were observed. The morphologies of labelled cells resembled those of neurons observed in Golgi studies of the human cerebral cortex. The presence of calcium binding proteins and NADPH-diaphorase in these cells suggests a possible inhibitory role as GABAergic neurons. The persistence of Cajal-Retzius cells in the adult cerebral cortex supports the idea that they undergo developmental dilution rather than postnatal degeneration.
- PublicationOpen AccessCholecystokinin, acting through the A receptor subtype, stimulates the proliferative activity of adrenocortical cells and thymocytes in the ra(Murcia : F. Hernández, 1999) Malendowicz, L.K.; Tretjer, M.; De Caro, Raffaelle; Jedrzejczak, N.; Brelinska, R.; Markowska, A.; Nussdorfer, G.G.; Nowak, M.Cholecystokinin (CCK) is a multifunctional regulatory peptide, which acts through two main subtypes of receptors, named CCK-A and CCK-B. Evidence indicates that CCK modulates cell proliferation in various tissues in a paracrine manner, and proofs are available of the presence of CCK in both adrenal glands and thymus. Hence, we have investigated the possible mitogenic action of this peptide on these two tissues, by evaluating the %o of metaphase-arrested cells after vincristin injection (mitotic index). The systemic administration of CCK (three subcutaneous injections of 20 nmollkg, 28, 16 and 4 h before the sacrifice) increased the mitotic index in both the outer adrenal and thymus cortexes of immature (20-day-old) rats and the enucleated adrenal gland of adult (2-month-old) animals at day 5 and 8 of regeneration. The simultaneous administration of equimolar doses of a selective CCK-A receptor antagonist blocked the effect of CCK, while a CCK-B antagonist was ineffective. These findings indicate that CCK exerts a marked CCK-A-mediated proliferogenic effect on both adrenal cortex and thymus in the rat, the physiological relevance of which, however, remains to be demonstrated. In fact, the administration of the CCK-A antagonist alone was ineffective, thereby casting doubts on the role played by endogenous CCK in the maintenance and stimulation of adrenal and thymus growth.
- PublicationOpen AccessCytokeratin expression patterns in normal and malignant urothelium, a review of the biological and diagnostic implications(Murcia : F. Hernández, 1999) Southgate, J.; Harnden, P.; Trejdosiewicz, L.K.The cytokeratins are the intermediate filament proteins characteristic of epithelial cells. In human cells, some 20 different cytokeratin isotypes have been identified. Epithelia1 cells express between two and ten cytokeratin isotypes and the consequent profile which reflects both epithelial type and differentiation status may be useful in tumour diagnosis. The transitional epithelium or urothelium of the urinary tract shows alterations in the expression and configuration of cytokeratin isotypes related to stratification and differentiation. In transitional cell carcinoma, changes in cytokeratin profile may provide information of potential diagnostic and prognostic significance. The intensification of immunolabelling with some CK8 and CK18 antibodies may underly an active role in tumour invasion and foci of CK17-positive cells may represent proliferating populations. Loss of CK13 is a marker of grade and stage and de novo expression of CK14 is indicative of squamous differentiation and an unfavourable prognosis. However, perhaps the most important recent finding is the demonstration that a normal CK20 expression pattern is predictive of tumour non-recurrence and can be used to make an objective differential diagnosis between transitional cell papilloma and carcinoma. This review will consider cytokeratin expression in urothelium and discuss the application of cytokeratin typing to the diagnosis and prognosis of patients with TCC.