Biomedical subjects
Publications and source records attributed to Leopold Sliwa.
Soybean diet, a rich source of phytoestrogenes, affects negatively on the potential fecundity in male mice. It causes spermatogenesis impairment which is manifested by changes in testicular histology. Germ epithelium becomes darker and sheds and a number of produced spermatozoa decreases. On the other hand a number of testicular macrophages significantly rises in Leydig glands.
The aim of this article was to present a simple classification of phytoestrogens, their approximate content in food products as well as their synthesis, biotransformation and activity in human organism. Having various mechanisms of action, phytoestrogens display both beneficial and adverse effects on physiological processes. Several positive health effects have been associated with phytoestrogens, such as a protective role against the development of cancers, proestrogenic effects (particularly with postmenopausal women) and beneficial influence on cardiovascular and osseous systems. Adverse effects of phytoestrogens have been observed in fetuses and young specimens. Limited studies have displayed disorders in morphology and physiology of the male reproductive system. High plasma phytoestrogens level inhibits a cellular activity of some enzymes, e.g. enzymes involved in the synthesis of steroid hormones. Direct contact with exogenous, environmental estrogens depends on human diet and it can be variable in different populations.
The activation of the egg cell metabolism by the spermatozoon which connects with it upon the moment of fertilization may by the result of the influence of the membrane receptors of the gametes or of the presence of an activating factor in the spermatozoon's cytoplasm carried by the male gamete into ooplasm. The first reaction observed in the cytoplasm of the activated oocyte is the increase of the level of calcium ions which determines the activation of many cytophysiological processes. Currently, a prevailing opinion is that an undulating, oscillating increase of the level of Ca2+ is caused by the influence of the activating spermatozoon factor and does not depend on the membrane receptors. The paper presents the survey concerning this little-known but important aspect of fertilization.
The presented paper is the survey of the most important literature concerning one of the basic biological properties of spermatozoa which is their chemotaxis during the process of fertilization. During the recent years a significant progress in the knowledge of this matter has been observed, especially in relation to human and mammal spermatozoa. A natural chemotactic factor is, in the case of mammals, the vesicle fluid. It is not known, however, which of its components is of the crucial importance. Numerous hormones, cytokines and other growth factors as well as other components of the vesicle fluid have been described as chemoattractants. It can be concluded from the research carried out so far that the chemotactic activity of the vesicle fluid results from its complex composition, and not from the existence of one chemical substance which could be crucial for the process.
Tettigonia ussuriana and T. dolichopoda maritima differ in the length of tegmina, details in venation, and in females in details of the subgenital plate. The two species of the genus Tettigonia have the same number and morphology of autosomes but a different morphology of the X chromosome: in T. ussuriana it is metacentric, whereas in T. dolichopoda maritima acrocentric. In both species, euchromatic zones and breaks of one or to chromatids during meiosis and mitosis in the X chromosome were observed. Additionally, B chromosomes were noted in most individuals of both species.