Polyploidy and polyteny in the trophoblast cells of the mink]

According to cytophotometry, trophoblast cells in the mink placenta are both diploid and polyploid, the ploidy level ranging from 2c to 64c. A great number of mink trophoblast cells were seen to divide mitotically. In addition to the ordinary mitotic figures, polyploid mitoses as well as abnormal mitotic figures were observed. Non-classic polytene chromosomes, peculiar to the mammalian trophoblast, appeared in the mink trophoblast cells to have the highest ploidy. A relatively low ploidy degree is due, probably, to a lesser invasive activity of the mink trophoblast cells as compared to the rodent giant trophoblast cells.     

Histological and immunohistochemical effects of Curcuma longa on activation of rat hepatic stellate cells after cadmium induced hepatotoxicity

The liver is a target for toxic chemicals such as cadmium (Cd). When the liver is damaged, hepatic stellate cells (HSC) are activated and transformed into myofibroblast-like cells, which are responsible for liver fibrosis. Curcuma longa has been reported to exert a hepato-protective effect under various pathological conditions. We investigated the effects of C. longa administration on HSC activation in response to Cd induced hepatotoxicity. Forty adult male albino rats were divided into: group 1 (control), group 2 (Cd treated), group 3 (C. longa treated) and group 4 (Cd and C. longa treated). After 6 weeks, liver specimens were prepared for light and electron microscopy examination of histological changes and immunohistochemical localization of alpha smooth muscle actin (αSMA) as a specific marker for activated HSC. Activated HSC with a positive αSMA immune reaction were not detected in groups 1 and 3. Large numbers of activated HSC with αSMA immune reactions were observed in group 2 in addition to Cd induced hepatotoxic changes including excess collagen deposition in thickened portal triads, interlobular septa with hepatic lobulation, inflammatory cell infiltration, a significant increase in Kupffer cells and degenerated hepatocytes. In group 4, we observed a significant decrease in HSC that expressed αSMA with amelioration of the hepatotoxic changes. C. longa administration decreased HSC activation and ameliorated hepatotoxic changes caused by Cd in adult rats.     

Inhibition of interferon secretion by vinblastine

The plant alkaloids vinblastine and colchicine are known to arrest cells in mitosis by virtue of their binding to spindle protein. These drugs are also capable of binding to microtubule protein and causing these structures to disaggregate into nonfunctional subunits (1, 2). Microtubular structures are thought to be involved in the secretory process of a number of proteins including insulin (7), collagen (4), and thyroid hormone (12). In this report we present our findings on the effects of these two drugs on the synthesis and secretion of interferon in a high producing human foreskin fibroblast strain (FS-4) (11).     

Synthesis and evaluation of biological activity for dual-acting antibiotics on the basis of azithromycin and glycopeptides

One of the promising directions of the combined approach is the design of dual-acting antibiotics – heterodimeric structures on the basis of antimicrobial agents of different classes. In this study a novel series of azithromycin-glycopeptide conjugates were designed and synthesized. The structures of the obtained compounds were confirmed using NMR spectroscopy and mass spectrometry data including MS/MS analysis. All novel hybrid antibiotics were found to be either as active as azithromycin and vancomycin against Gram-positive bacterial strains or have superior activity in comparison with their parent antibiotics. One compound, eremomycin-azithromycin conjugate 16, demonstrated moderate activity against Enterococcus faecium and Enterococcus faecalis strains resistant to vancomycin, and equal to vancomycin’s activity for the treatment of mice with Staphylococcus aureus sepsis.     

Mitochondrial Calcium Transport Systems: Properties, Regulation, and Taxonomic Features

Currently available information on properties and regulation of mitochondrial Ca2+ transporting systems in eukaryotic cells is summarized. We describe in detail kinetic properties and effects of inhibitors and modulators on the energy-dependent Ca2+ uptake through the Ca2+ uniporter, as well as on Na+-dependent and Na+-independent pathways for Ca2+ release in mammalian mitochondria. Special emphasis is placed on Ca2+ transport systems (for ion uptake and release) in mitochondria of higher plants, algae, and yeasts. Potential physiological implications of mitochondrial Ca2+ fluxes (influx and efflux), e.g., regulation of activity of Ca2+-dependent enzymes of the Krebs cycle, maintaining of cellular Ca2+ homeostasis, and engagement in pathophysiological processes, are discussed.     

Mechanisms and frequency of nuclear divisions in trophoblast and decidua cells during postimplantation embryogenesis in the mouse

The finding of amitotic division of trophoblast cell nuclei in blastocysts of the American mink (Mustela vison), which has an obligatory period of delay in implantation (obligatory embryonic diapause) in its ontogenesis, led us to study the mechanisms and frequencies of division of trophoblast and decidua cell nuclei during the postimplantation embryogenesis of mouse (Mus musculus), which does not exhibit an obligatory diapause nor amitosis in blastocysts. It has been established that the main mechanism underlying the cell nuclei division in both tissues (trophoblast and decidua) forming the placenta is amitosis. These data suggest that the occurrence of an obligatory embryonic diapause in ontogenesis of certain animal species is related not only to the delay in implantation, but also to the alteration in the chronology of all processes of embryogenesis.