Increase in the Strength of Synchronization between the Baroreflex Waves of Blood Pressure and Heart Rate Due to the Lower Body Negative Pressure Effect

Human Physiology - The lower body negative pressure (LBNP) effect has been studied in terms of phase synchronization between spontaneous oscillations of blood pressure (BP) and heart rate (HR). The...     

Immune proteasomes and immunity

A lot of facts that require understanding have been accumulated since immune proteasomes were discovered and their relationship with the immune response was established. For example, why are immune proteasomes present in all studied mammalian organs and tissues, including nonlymphoid tissues? What is responsible for differences in the ratio of immune to constitutive proteasomes in different organs? Are the functions of immune proteasomes related to the T-cell immune response alone, as was shown initially, or not? Are immune proteasomes formed simultaneously in different organs during ontogenesis? An attempt is made in this review to answer these and other related questions.     

Formation of immune proteasomes and development of immune system in ontogenesis of mammals

Current concepts of the structure of immune proteasomes and their role in immune response have been considered. The main attention has been paid to the formation of immune proteasomes in secondary lymphoid and nonlymphoid organs during ontogenesis of mammals. The causes of ineffective formation of immune system in early postnatal development have been discussed.     

The effect of an acoustic calling signal on the sex hormone level in the blood of white mice

The action was studied of synthesized acoustic signals, similar to the natural invocatory ones by their characteristics, on the level of sexual hormones in male and female mature laboratory mice, and also the dependence of these hormonal shifts on rhythmic organization of the artificial sound signals. As a result of the experiments it was convincingly shown that synthesized acoustic signal with the frequency of 3500 Hz (S-1) caused a functional load on the glands of internal secretion which was testified by statistically significant increase in the level of sexual hormones in the blood of males (by testosterone and extradiole) and female mice (by extradiole and progesterone). In order to clear up the role of rhythmic organization of signal studies were conducted with the application of synthetic acoustic signal (S-2), different from S-1. The analysis of the data revealed the absence of significant changes in the level of sexual hormones both in males and in females during S-2 sounding.     

Ca2+-induced change of dorsal-ventral polarity in frog (Rana temporaria) eggs

Abstract. The effect of local Ca²⁺ administration 10–20 min after fertilization and during artificial activation was examined in Rana temporaria eggs. Ca²⁺ was injected into the pigmented region near the boundary between pigmented and unpigmented domains. The locations of egg gray crescent (GC) and dorsal lip of blastopore (DLB), as predictors of the dorsal region in embryos, as well as the measurements of angles between GC middle and sperm entry site were observed. In more than 70% of the cases, microinjection of Ca^{2 +} into subcortical cytoplasm and egg pricking in high-Ca^{2 +} solutions induced GC and DLB formation near the injection site. The formation of Ca²⁺-induced GC occurred mostly as in control eggs. In addition premature displacement of the egg surface was observed near the prick site in high-Ca^{2 +} solutions. GC formation occurred by displacement of the pigmented surface in the same direction as earlier wound translocations. These results show that Ca²⁺ injection determines the direction of the surface movement.