Physiological aspects of apoptosis

Study of apoptosis is a new stage in development of biomedical sciences. At the cellular level the process is realised on account of efferents supporting an equilibrium among proliferation, differentiation, and programmed cell death. Significance of each of the factors is determined by its role in physiological systems functioning. Cell death infringement may cause pathological conditions and diseases followed by both degenerative and proliferative changes.     

Exosome-derived uterine microRNAs isolated from cows with endometritis impede blastocyst development

As a common disease of cows occurring during their perinatal period, endometritis is known to affect fertility. At present, the studies on endometritis mainly focus on preventing microbial invasion. However, the mechanism that uterine inflammation affects embryo activity and implantation is unclear. Mainly containing lipids, proteins, mRNAs, and microRNAs, exosomes widely exist in various tissues and body fluids. Exosome extractions were used by commercial kits and confirmed through morphological examinations and Western blot. After exosomes’ mRNA profiles were generated using RNA sequencing, it was investigated how uterine cavity fluid exosomes affect the developmental competence of in vitro fertilization (IVF) embryos in case of endometritis. In this study, the isolated exosomes were spherical particles with a diameter of 30–150 nm according to the transmission electron microscopy. Identified with Western blotting, positive CD63 and CD9 expressions showed that the isolated exosomes could be used for the subsequent tests. We found 118 differentially expressed miRNAs in the exosomes of the uterine cavity fluid in healthy cows and those with endometritis, among which, 52 miRNAs were down regulated and 66 up regulated. Furthermore, the qRT-PCR results confirmed the up-regulation of three miRNAs and down-regulation of six miRNAs, which were consistent with the deep sequencing results. IVF embryos co-incubated with the endometritis exosomes significantly decreased the blastocyst formation rate in comparison with those co-incubated with the healthy exosomes (21.84+3.17 vs. 32.37+2.69). Therefore, exosome miRNAs may be a cause of infertility in cows with endometritis.     

Effects of indomethacin on uterine capillary permeability and blastocyst development in rabbits

Increased capillary permeability at implantation sites was demonstrated in rabbits by extravasation of intravascular blue dye on day 7 of pregnancy. Subcutaneous administration of indomethacin (Id, 8 mg/kg twice daily) on days 4–6 of pregnancy inhibited this uterine blueing response and appeared to reduce the size of implantation swellings. To test the latter observation blastocyst diameter and development of the embryonic disk were assessed at 144 hr . In females receiving indomethacin at the dose level which inhibited uterine blueing, blastocysts were significantly smaller than those from control females. Developmental staging of embryonic disks revealed only slight differences between the smaller (Id-treated) blastocysts and control blastocysts. No effect of Id was seen on ovarian function as judged by luteal weights and plasma progesterone and estradiol levels. Since the major biological effects of indomethacin are due to its inhibition of prostaglandin synthesis, it appears that prostaglandins may play a role in the uterine response to blastocyst stimulation and in the expansion of blastocysts in the rabbit.     

Physiological aspects on catecholamine sampling

Catecholamine (CA) determinations are valuable tools in studies of sympatho-adrenal activity. However, several methodological problems should be considered when designing experiments and interpreting plasma CA results. The commonly assessed antecubital venous noradrenaline (NA) concentrations reflect local nerve activity, since about half of this NA is derived from the forearm tissues. Sympathetic nerve activity is not uniform, but may vary considerably between organs. Overall sympathetic activity is best assessed by measurements of NA in arterial or mixed venous blood. Venous adrenaline (ADR) levels may also be unrepresentative due to marked and variable extraction in the peripheral tissues. Urinary NA and ADR excretion studies still provide valuable information. Regional studies of NA overflow from individual organs give good estimates of local nerve activity and will increase the understanding of the functional organization of the sympathetic nervous system.     

Physiological aspects of intensifying yeast growth

The possibilities of intensifying yeast growth during flow cultivation via an increase in the rate of medium flow and the concentration of carbon-containing substrate are considered. It is found that stabilization of optimum specific substrate loads provides maximum economic coefficient of the process. Stabilization of optimum specific loads of carbon-containing substrates during a three-stage flow cultivation of yeasts in a medium with n-alkanes allowed the throughput of a battery of fermenters to be elevated 1.84-fold. Alternation of flow chemostatic and turbidostatic yeast cultures was accompanied by a fivefold increase in the maximum specific growth rate.     

Physiological aspects of intensifying yeast growth

The possibilities of intensifying yeast growth during flow cultivation via an increase in the rate of medium flow and the concentration of carbon-containing substrate are considered. It is found that stabilization of the optimum specific substrate loads provides the maximum economic coefficient of the process. Stabilization of the optimum specific loads of carbon-containing substrates during a three-stage flow cultivation of yeasts in a medium with n-alkanes allowed the throughput of a battery of fermenters to be elevated 1.84-fold. Alternation of flow chemostatic and turbidostatic yeast cultures was accompanied by a fivefold increase in the maximum specific growth rate.     

Physiological and pathophysiological aspects of ceramide

Activation of cells by receptor- and nonreceptor-mediated stimuli not only requires a change in the activity of signaling proteins but also requires a reorganization of the topology of the signalosom in the cell. The cell membrane contains distinct domains, rafts that serve the spatial organization of signaling molecules in the cell. Many receptors or stress stimuli transform rafts by the generation of ceramide. These stimuli activate the acid sphingomyelinase and induce a translocation of this enzyme onto the extracellular leaflet of the cell membrane. Surface acid sphingomyelinase generates ceramide that serves to fuse small rafts and to form large ceramide-enriched membrane platforms. These platforms cluster receptor molecules, recruit intracellular signaling molecules to aggregated receptors, and seem to exclude inhibitory signaling factors. Thus ceramide-enriched membrane platforms do not seem to be part of a specific signaling pathway but may facilitate and amplify the specific signaling elicited by the cognate stimulus. This general function may enable these membrane domains to be critically involved in the induction of apoptosis by death receptors and stress stimuli, bacterial and viral infections of mammalian cells, and the regulation of cardiovascular functions.     

Assessment of sheep blastocyst effects on neutral lipids in the uterine caruncular epithelium

Neutral lipids in the maternal uterine caruncular epithelium were studied by histochemical localization with Oil Red O. Results using a scoring system of 1 (negligible lipid) to 5 (maximal lipid) showed that intraepithelial lipid stores were minimal until Days 7-8 of the oestrous cycle and then increased to have a mean score of 4.4 on Day 14-15. In early pregnancy, although relatively high with a mean score of 3.2 at Day 15-16, such neutral lipids were significantly lower than those present at a comparable stage in the oestrous cycle. Thereafter, levels declined to a mean score of 1 on Days 21-23 of pregnancy. Such neutral lipid loss appears to be one of the first signs of the maternal response to the implanting embryo and precedes morphological evidence of transformation of either maternal or fetal tissues.     

Comparative aspects of opioid-dopamine interaction

1. Opiate receptors are found in invertebrate as well as mammalian systems, often in proximity to dopamergic systems. This review summarizes the interrelationships between these two transmitter systems in invertebrates. 2. The comparative data discussed here are of considerable significance. They recall that the opioid-dopamine relationships first demonstrated in the mammalian nervous system also apply to invertebrates and are therefore of more general importance. The results obtained in the mollusk Mytilus strengthen the concept that the activity of dopaminergic neurons may be modulated by afferent opioid signals and that, even in "more primitive" animals, interneuronal transfer of information is more complex than formerly visualized. Furthermore, the data indicate that endogenous opioids may exert tonic control over dopamine metabolism, thus implying interdependence of the two systems.