Apoptogenic effect of the lipophilic o-naphthoquinone CG 10-248 on rat hepatocytes: light and electron microscopy studies

CG 10-248 (3,4-dihydro-2,2-dimethyl-9-chloro-2H-naphtho[1,2b]pyran-5,6-dione; CG-NQ), a beta-lapachone analogue, modified the ultrastructure of rat hepatocytes, as demonstrated by light and electron microscopy. After 4 h incubation with 100 microM CG-NQ, the following effects were observed: (a) nuclear chromatin condensation; (b) chromatin fragmentation; (c) displacement of mitochondria, concentrated around the nucleus; (d) disruption or expansion of mitochondrial outer or inner membranes, respectively; (e) displacement and alteration of endoplasmic reticulum (rough and smooth); (f) decrease of microvilli; (g) blebbing of plasma membrane and production of apoptotic bodies formed by folding of plasma membrane fragments around mitochondria or peroxysomes; and (h) production of hydrogen peroxide. Expression of such effects varied according to hepatocyte samples and taken together strongly support an apoptotic action of CG-NQ dependent on reactive oxygen species.

Activation of macrophage functions by growth factor present in uterus and embryo extract of pregnant mouse

A pregnant mouse uterus and embryo extract (PMUE) that contains growth hematopoietic factor (M-CSF or CSF-1), was used to test its action on the phagocytic and digestive functions of macrophage. Macrophages incubated with and without PMUE for 24 hours previous to each experiment were compared. A good phagocytosis of Trypanosoma cruzi by macrophages incubated with PMUE, was observed on video microscopy. No phagocytic activity was observed in the macrophages deprived of PMUE 24 hours before. The studies of phagocytic and degradative behavior of macrophages by both soluble and particulated (S. aureus) complex 125I-antibodies showed that total binding of soluble ligands was almost double in the group of macrophages incubated with PMUE. Both the soluble and particulated ligands were digested more efficiently by the macrophages stimulated by PMUE. Counting the macrophages with trypan blue, an equal viability was found, of the cells incubated with and without PMUE. From the experimental data obtained, we may conclude that the hematopoietic growth factor present in PMUE is essential for phagocytic and degradative functions of macrophages.

Sperm association in the rat epididymis

During dissolution of drops obtained by puncture of rat epididymis in distal caput, mid corpus, proximal and distal cauda we observed in the last tworegions the appearance of a new sperm association which we call rosette and the formation in the same two regions of dense clusters of non-motile degenerating spermatozoa already described in the rat was deferens. Rosettesbecome organized in the proximal cauda by head to head sperm contact through a filamentous PAS positive material. By video microscopy was observed thedilution of a dense drop of cauda epididymal content in a balanced salt solution at 36 degrees C. In less than 3 min, rosettes become dispersed intosingle sperm with a display of intense motility which starts immediately after dilution. A glycoprotein with cohesive properties secreted by the epididymal epithelium is postulated as the factor promoting rosette formation. We confirm that dense clusters correspond to degenerating spermatozoa and describe its first appearance in the epididymal proximal cauda with increase in number toward was deferens

Epididymal transit and morphology of the hamster sperm head

Los cambios que experimenta la cabeza del espermatozoide de hamster durante su tránsito por el epidídimo fueron analizados con técnicas morfológicas, de criofractura y morfométricas. Desde el punto de vista morfológico se comprueba una modificación del ángulo formado por el acrosoma y la región postacrosomal que de recto en espermatozoides del caput pasa a obtuso en espermatozoides de cauda. En cuanto a la criofractura se estudió la distribución de las partículas intramembranosas en la membrana plamática (IMPS). Se describe una disposición regular de las IMPS formando una trama hexagonal en el borde convexo del acrosoma. Esta trama está presente en espermatozoides extraídos del caput y no se observa en los extraídos de la región caudal del epidídimo. La región postacrosomal revela dos cambios notables: la presencia de una corona de barras adyacentes al cuello y formada por IMPS de 10 nm en espermatozoides del caput que se desorganiza en espermatozoides extraídos del epidídimo caudal y el incremento en estos del número de IMPS de 10 nm dispersas por toda la región postacrosomal. Postulamos que el aumento de IMPS en la región postacrosomal se relaciona con la incorporación de glicoproteínas secretadas por epidídimo como factor (es) de maduración y reconocimiento intergamético