Characterization of lake minnow Eupallasella percnurus semen in relation to sperm morphology, regulation of sperm motility and interpopulation diversity.

Sperm morphology and regulation of sperm motility of lake minnow Eupallasella percnurus, an endangered cyprinid, were investigated. Milt characteristics from two isolated populations of E. percnurus were compared to characterize the interpopulation diversity. Electron microscopic studies revealed that E. percnurus spermatozoa comprise simple, uniflagellate, anacrosomal aquasperm with species-specific features as an eccentrically located implantation of nuclear fossa and eccentric insertion of flagellum. Sperm motility was significantly inhibited by relatively low ion concentrations (150, 150 and 8 mM for NaCl, KCl and CaCl2 , respectively). Sperm maintained a high motility rate over a wide pH range (5.5-10.5), which may reflect adaptation to a highly variable environment. The two E. percnurus populations were markedly different in milt volume, sperm concentration, seminal plasma pH, sperm motility and beat cross frequency, which may result from genetic differences and environmental conditions.

Molecular mechanism of SHP2 activation by PD-1 stimulation.

In cancer, the programmed death-1 (PD-1) pathway suppresses T cell stimulation and mediates immune escape. Upon stimulation, PD-1 becomes phosphorylated at its immune receptor tyrosine-based inhibitory motif (ITIM) and immune receptor tyrosine-based switch motif (ITSM), which then bind the Src homology 2 (SH2) domains of SH2-containing phosphatase 2 (SHP2), initiating T cell inactivation. The SHP2-PD-1 complex structure and the exact functions of the two SH2 domains and phosphorylated motifs remain unknown. Here, we explain the structural basis and provide functional evidence for the mechanism of PD-1-mediated SHP2 activation. We demonstrate that full activation is obtained only upon phosphorylation of both ITIM and ITSM: ITSM binds C-SH2 with strong affinity, recruiting SHP2 to PD-1, while ITIM binds N-SH2, displacing it from the catalytic pocket and activating SHP2. This binding event requires the formation of a new inter-domain interface, offering opportunities for the development of novel immunotherapeutic approaches.

[Report from the conference on "safe and hygienic learning conditions as indispensable elements of elementary schools' functioning"]. / Sprawozdanie z konferencji pt. "bezpieczne i higieniczne warunki nauczania niezbednym elementem funkcjonowania szkól podstawowych".

The conference was organized in Warsaw on the 14th of November 1997, by the Main Section of School Hygiene of the Polish Society of Hygiene. 202 people took part in the conference. They represented following institutions: a sanitary inspection, a health care service, academy institutes, pedagogical institutions, community councils. The purpose of the meeting was to point out and widespread local initiatives and ideas, appearing in various regions of Poland, that concern the following topics: 1: improvement of health conditions in schools, 2) improvement of conditions and realization's methods of increased number of physical training lessons in schools (a gradual increase from 3 hours a week at the present time to 5 in the year 2000), 3) providing actions to minimize the number of accidents among children and adolescents. There were panel discussions concerning the problems mentioned above. Many conclusions were formulated as the result of the discussion, out of which the most important are: ad 1) Maintaining the conditions of proper education demands cooperation between schools' headquarters and community councils and an initiative in seeking allies and sponsors. Examples of the activities of community councils to maintain proper safe and hygienic conditions in education should be propagated. These examples can be applied in another areas. ad 2) There is a dramatic shortage of facilities. Schools try to fulfil the increased requirements by: utilizing elements of natural environment, profiting from the spontaneous activity of children and parents, extending a traditional curriculum offered by new elements of physical culture. Increasing the number of physical training classes gives a chance to create social attitudes during these classes and health behaviour. ad 3) Accident risk in schools should be eliminated by carrying out a systematic many-sided and preventive activity. The coordination of actions should exist on all levels of local and national administration. In schools decisions concerning organizational solutions should be taken up, with the active involvement of headquarters, teachers, administrative workers and parents.

Alpha-ketoglutarate stabilizes redox homeostasis and improves arterial elasticity in aged mice.

The objective of this study was to evaluate the effect of α-ketoglutarate on redox state parameters and arterial elasticity in elderly mice. Mice in the control group were fed with standard diet, while the experimental animals received the diet supplemented either with calcium (Ca-AKG) or sodium salt of α-ketoglutarate (Na-AKG). The experimental animals were divided into 4 groups with 10 individuals in each: control I (12 months old), control II (2 months old), experimental group I fed with Ca-AKG (12 months old) and experimental group II fed with Na-AKG (12 months old). Mice treated with Ca-AKG as well as the control II animals demonstrated significantly higher level of total antioxidant status (TAS), comparing to the control I animals and those treated with Ca-AKG. Thiobarbituric acid reactive substances (TBARS) level in blood plasma was found significantly lower in young and Ca-AKG treated mice. TBARS liver concentration was significantly different in each examined group. The study also demonstrates the decrease in TBARS level in Ca-AKG treated animals. Treatment with Na-AKG significantly increased glutathione peroxidase activity and decreased the activity of superoxide dismutase. The presented results suggest that Ca-AKG protects the organism against the free radicals related elderly processes. The study presents also the effect of Ca-AKG treatment on arterial elastic characteristics in elderly mice. The beneficial effect of Ca-AKG on ageing organisms was confirmed via redox state stabilization and blood vessel elasticity improvement.