Histology and histopathology Vol. 5, nº 3 (1990)
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- PublicationOpen AccessSerotonin-producing pancreatic endocrine tumour. Histological, ultrastructural and immunohistochemical study of a case(Murcia : F. Hernández, 1990) Kanavaros, Panagiotis; Hoang, Catherine; Le Bodic, Marie Francoise; Polivka, Marc; Hautefeuille, PierreSerotonin-producing pancreatic endocrine tumours are rare neoplasms which in most cases exhibit malignant biological behaviour. These tumours, in the majority of the well-documented cases, are composed of argyrophil- and argentaffin-positive cells which contain large pleomorphic neurosecretory granules. In contrast, argyrophilic non-argentaffin pancreatic endocrine tumours with tumour cells containing round neurosecretory granules are exceptional. In this study we describe such a tumour not associated with clinical evidence of carcinoid syndrome in a 60-year-old woman. Histological examination revealed tumour extension in pancreatic lymphatic vessels and veins but no evidence of locoregional or distant metastases. Ten months after surgery the patient showed no recurrence of the disease. Immunohistochernistry revealed cytoplasmic serotonin production in the tumour cells which were negative for anti-gastrin, insulin, glucagon, somatostatin, pancreatic polypeptide (PP), vasoactive intestinal peptide (VIP) and ACTH. This study emphasizes the usefulness of combined ultrastructural and immunohistochemical investigations in order to identify and characterize the rare pancreatic endocrine tumours with serotonin production.
- PublicationOpen AccessEffects of photoperiod and temperature on testicular function in amphibians(Murcia : F. Hernández, 1990) Paniagua, R.; Fraile, Benito; Sáez, F.J.Most amphibians present an annual testicular cycle characterized by a quiescent period (late autumn-winter) and a spermatogenic period (spring and summer). At the end of the period of spermatogenesis undifferentiated interstitial cells transform into steroid-secreting Leydig cells which regress in spring at the beginning of the new spermatogenetic cycle. The testicular cycle is controlled by the pituitary gonadotropin levels which are high in autumn and winter, low in spring and increase temporarily in the middle of summer. Photoperiod and temperature seem to be the most important externa1 factors involved in the regulation of this cycle in many amphibian species since the colder the geographic area, the longer the quiescent period and the shorter the spermatogenic period. This suggests the occurrence of a potentially continuous cycle in these species, in contrast with that which occurs in other species having an endogenous rhythm of testicular function which is much less sensitive to environmental factors. Although the specific response to temperature can vary widely between species, the most frequent observation in amphibians with a potentiaiiy continuous cycle is that exposure to mild temperatures (15-20° C, according to the spring temperatures of the different geographic areas) stimulates spermatogenesis even during the period of testicular quiescence. If this mild temperature is combined with a long photoperiod, complete spermatogenesis is attained. Experiments performed during the period of germ-cell proliferation (development from spermatogonia to round spermatids) indicated that low temperatures (below 11° C) as well as short photoperiods (less than 8 h of light) hinder germcell proliferation. Moderately high temperatures (about 30° C) do not impair this proliferation. In the newt Offprint reqoests to: Dr. R. Paniagua, Department of Cell Biology and Genetics, University of AlcalA de Henares, E-28871 Alcala de Henares, Madrid, Spain Triturus marmoratus, it has been shown that an excessively long photoperiod (over 16 h) has the same effect as a short photoperiod. In this species eyes are not required for the testicular photoperiodic response. Photoperiod appears to have no effect on spermiogenesis (differentiation of round spermatids into spermatozoa), because once round spermatids are formed, spermiogenesis will occur even in total darkness. Mild temperatures seem to be necessary for spermiogenesis as well as for androgen biosynthesis because neither process will take place at extreme temperatures. Results on the effect of photoperiod in steroidogenesis differ between species.
- PublicationOpen AccessEffect of chronic alcoholism on the human hippocampus(Murcia : F. Hernández, 1990) Bengochea, O.; Gonzalo, L. M.The effect of chronic alcoholism on the human hippocampus was studied in 21 patients, divided in 4 groups: Group A under 45 years, group B 46-59 years, group C 60-69, and Group D over 70 years; and compared with age-matched control patients who died without neurological complications. The gyrus d~ntatus and the ammonic fields CA1 through CA4 were analyzed by counting the number of neurons and the size of the nuclear area. Both parameters were evaluated statistically. The most important findings were a high neuronal loss in alcoholics in the first age group. In addition, the hippocampal neurons failed to display a vicarious reaction, since the nuclei did not show any increase in size despite the intense neuronal loss. Our results point out an early neuronal loss in the hippocampus of alcoholic patients higher than agematched controls, as well as a lack of reaction to the neuronal insult .
- PublicationOpen AccessEffect of ethanol on the cerebellar cortex of the chick embryo(Murcia : F. Hernández, 1990) Quesada, A.; Prada, F. A.; Espinar, A.; Genís-Gálvez, J. M.
- PublicationOpen AccessScanning electron microscopic study of natural killer cell-mediated cytotoxicity(Murcia : F. Hernández, 1990) Fernández-Segura, E.; García, J.M.The interaction between human natural killer (NK) celis and NK-susceptible target cells, as well as the mechanism involved in target cell lysis, were studied with scanning electron microscopy (SEM). Low density human peripheral blood lymphocytes, highly enriched with large granular lymphocytes (LGL), were used as effector cells, and K562-cells were used as NK-susceptible target ceiis. The surface features of LGLINK cells were examined under SEM. In the area of interaction, NWtarget-cell conjugates showed microvilli andor filipodia, and extensive areas of intercellular contact. In addition, the effector cells in some NWtargetcell conjugates were polarized toward the target cell. Changes in target cell surface features included loss of microvilli, large surface blebs and the appearance of small pore-like lesions on the cell membrane. Our findings show that target cell lysis occurred by apoptosis and plasma membrane lesions analogous to those seen during complement-mediated cytotoxicity.