Histology and histopathology Vol. 9, nº 2 (1994)
Ir a Estadísticas
Permanent URI for this collection
Browse
Recent Submissions
- PublicationOpen AccessThe fate of the luminal asymmetric unit membrane of the superficial cell of the rat transitional epithelium(Murcia: F. Hernández, 1994) Zhang, S.X.; Seguchi, H.The fate of the luminal asymmetric unit membrane (AUM) of the superficial cell of the transitional epithelium of the rat urinary bladder was electron microscopically and cytochemically investigated using exogenously administered horseradish peroxidase (HRP) as tracer. HRP-positive discoidal vesicles were formed by the folding of the AUM of the luminal surface plasma membrane. With the passage of time, these vesicles changed their shapes and were finally transformed into lysosomes by the following possible routes: 1) by becoming multivesicular bodies (MVBs); 2) by directly fusing with lysosomes; and 3) by becoming autophagic vacuoles. Another possibility would be reutilization.
- PublicationOpen AccessEffects of prostaglandin Eq on the ultrastructure of the golden hamster parathyroid gland(Murcia : F. Hernández, 1994) Emura, S.; Utsumi, M.; Hayakawa, D.; Yamahira, T.; Terasawa, K.; Tamada, A.; Isono, H.; Shoumura, S.The effects of different ages on large vacuolar bodies in the parathyroid glands of golden hamsters after administration of prostaglandin E2 (PGE2) were investigated. In the parathyroid glands of the young and senile animals 15 min and the senile animals 60 min after administration of PGE2, the mean serum calcium concentration was significantly higher when compared to that of the young and senile control animals, respectively. In the experimental adult animals 60 min after administration of PGE2, the serum calcium concentration was seen to increase. In the parathyroid glands of the young animals 15 min and the adult and senile animals 60 min after administration of PGE2, the percent area occupied by large vacuolar bodies was significantly increased when compared to that of the young, adult and senile control animals, respectively. These findings suggest that the percent area occupied by large vacuolar bodies is increased in response to hypercalcemia induced by PGE2. It is thought that in the parathyroid glands suppressed by hypercalcemia there is a relationship between the percent area occupied by large vacuolar bodies and aging.
- PublicationOpen AccessIn favour of an oncofoetal concept of bronchogenic carcinoma development(Murcia : F. Hernández, 1994) Ten Have-pbroek, A.A.W.; Benfield, J.R.; Hammond, W.G.; Teplitz, R.L.; Dijkman, J.H.Our recent studies in a heterotopic model of non-small cell lung cancer in dogs (subcutaneous bronchial autografts treated with 3- ~i iethylchola~i threnhea) ve provided evidence that alveolar type I1 cells may newly arise during initial phases of bronchial carcino-genesis. In the light of these novel findings, which are in agreement with our observations in human non-small cell lung cancer, and in \~iew of present insighrs into embryonic lung differentiation, we discuss evidence that favours a new1. oncofoetal concept of bronchogenic carcinoma development. According to this concept, the primary cells of origin for these tilmors are undifferentiated primordial-like cells that derive from bronchial epithelial cells present in major bronchi or their divisions by retrodifferentiation. Such primordiallike cells of origin ~~nde rgnoo vel differentiation into the potential (alveolar, bronchial or primordial) tumor stem cells, which occupy the dividing cellular layers of the (pre)neoplastic lesions and constitute the actively dividing and invading part of the neoplasn~. Examples of tumors that may originate from alveolar tunlor stem cells are carcinon~aso f the bronchioloalveolar, papillary, acinar, and adenoid-cystic types. Squamous cell carcinon~asc ould possibly belong to this group as well, but much more evidence is required to reach conclusions regarding this type of cancer. We suggest that epithelial retrodifferentiation followed by novel differentiation (oncofoetal mechanism) is fundamental in bronchial carcinogenesis.
- PublicationOpen AccessCarbohydrates and soluble lectins in the regulation of cell adhesion and proliferation(Murcia : F. Hernández, 1994) Zanetta, J.P.; Badache, A.; Maschke, S.; Marschal, P.; Kuchler, S.There is a large body of suggestions that complex carbohydrates play a role in the regulation of cell adhesion and cell proliferation. Many reports have emphasized that proteoglycans. glycoproteins or glycolipids are participating to cell adhesion mechanisms. The use of polyvalent anti-carbohydrate antibodies and plant lectins as well as the use of glycosy lation inhibitors suggested that cell proliferation can be nlodulated by surface carbohydrates. The dating experiment of Burger and Noonan (1970) showing restoration of contact inhibition of malignant cells by monovalent concanavalin A was a determining experiment. However, in the latter as in the others, no precise mechanism was demonstrated how carbohydrates can be involved in adhesion and proliferation. New insights were opened with the discovery of vertrebrate membrane-bound and soluble lectins. The latter generally display agglutinating activities in in vitro systems, suggesting that they were potential cell adhesion molecules, by forming bridges between cell surface carbohydrates. These polyvalent molecules may be also considered as clustering agents for their cell surface ligands, conseq~~entlgye nerating signals for cell proliferation andlor differentiation.
- PublicationOpen AccessThe distribution of corticotropin-releasing factor immunoreactive neurons and nerve fibres in the brain of Gambusia affinis and Salmo trutta(Murcia : F. Hernández, 1994) Coto-Montes, A.; García-Fernández, J.M.; Del Brío, M.A.; Riera, P.The study was carried out on the distribution of neurons and fibres which contain the Corticotropin releasing factor-like (CRF) immunoreactivity in the encephalon of two species of teleosts, Gambusia affinis and Salmo trutta. The peroxidase-antiperoxidase (PAP) immunocytochemical technique was employed. The present study has shown differences between both species. In Gambusia affinis, positive neurons were observed in the area ventralis telencephali pars lateralis (VLT), in the nucleus praeopticus (NPO) and in the nucleus lateralis tuberis (NLT). The immunoreactive fibres were in the area ventralis telencephali, in the preoptic hypophyseal tract and in the hypophysis. In Salmo trutta the immunoreactive cells were seen in the pars magnocellularis and pars parvocellularis of the NPO and in cerebrospinal fluid (CSF) contacting neurons of the NLT. The pattern of distribution of immunoreactive fibres in Salmo trutta was different from that in Gambusia affinis. In addition to the distribution of perikarya in Gambusia affinis (in the VLT and in the preoptic hypophyseal tract), fibres were also observed in the tubero-hypophyseal tract and in the posterior hypothalamus. The hypophysis of Salmo trutta also presents an extensive labelling. The interspecific differences shown in the present study should be due to the different degree of evolution in the two species studied and to other causes, such as environmental ones.