Ultrastructural study of cat zona pellucida during oocyte maturation and fertilization.

The mammalian zona pellucida (ZP) is an extracellular glycoprotein structure formed around growing oocytes, ovulated eggs and preimplantation embryos. The specific functions of ZP are highly determined by its morphological structure. Studies on cat oocytes during maturation and after fertilization were undertaken, using routine transmission (TEM) and scanning electron microscopy (SEM). Two basic ZP layers - outer with rough spongy appearance and inner with smaller fenestrations and smooth fibrous network - were visible. Deposits, secreted by oviductal cells formed new layer, the so called oviductal ZP. After fertilization outer ZP showed rougher meshed network due to fusion between filaments as a consequence from sperm penetration while the inner was smoother with melted appearance. The presented data on the SEM and TEM characteristics of cat oocytes, together with our previous studies on carbohydrate distribution suggest that during oocyte maturation and fertilization ZP undergoes structural and functional rearrangements related to sperm binding and penetration.

Miltefosine decreases the cytotoxic effect of epirubicine and cyclophosphamide on mouse spermatogenic, thymic and bone marrow cells.

A new class of potent anticancer drugs, alkylphosphocholines has been recognized lately. Miltefosine (Hexadecylphosphochlorine, HPC) has been found to express select antineoplastic effect on human breast cancer skin metastases with simultaneous preservation of bone marrow proliferative activity and low clastogenicity. In the current study, we present data about the specific effect of two widely used cytostatics Cyclophosphamide (CP) and Epirubicine (ERb) applied separately or in combination with Miltefosine. C57BL6 mice were treated per os or intraperitonieally in doses corresponding to that in clinical use. Morphological, autoradiographic, ultrastructural and cytogenetic studies on spermatogenic, thymic and bone marrow cells were performed. It is found that compared with separate application, combinations of ERb or CP with Miltefosine slightly decreases spermatogonial proliferation and exerts milder effect on the structure of germinal and thymic cells. In addition, a lot of plasmocytes showed signs of active protein (antibody) synthesis. A significant reduction of aberrant chromosomes (clastogenicity) without changes in proliferative activity of bone marrow cells were recorded. In conclusion, the combine application of Miltefosine with ERb and CP decreased the destructive cytotoxic effects of ERb and CP on mouse spermatogenic and hematopoietic cells.

The effect of in vitro fibroblast growth factors on cell proliferation in pancreas from normal and streptozotocin-treated rats.

Fibroblast growth factors (FGFs) are potent mitogens for a wide variety of cells. In the present study we examined the potential morphogenic activities of the growth factors FGF1, FGF2 and FGF7, and cellular processes underlying morphogenesis, in pancreatic cells from streptozotocin diabetic newborn rats. The pancreases from control and diabetic newborn rats were microdissected and cultured in the presence of different doses of FGF1, 2 and 7 for 48 h. An additional incubation for 24 h was undertaken in the presence of bromo-deoxyuridine. The effect of the FGFs on bromo-deoxyuridine incorporation was analysed by means of immunocytochemistry. The most prominent stimulatory effect was found after application of FGF2 and 7 at a dose of 100 ng/l in endocrine and exocrine cells of diabetic rats. It is concluded that FGF2 and 7 might act as putative key-signalling molecules in the differentiation of pancreatic cells.