Serotonin receptors have been found in several reproductive organs as well as in the central nervous system. Serotonin-binding sites have been demonstrated in duck ovarian follicles and the testis, hamster ovaries, human granulosa cells and mouse placenta. Local production of serotonin by the rat ovary, oviduct, uterus and testis has also been reported. We analyzed the expression of three types of serotonin receptors: 5-HT1B, 5-HT2C and 5-HT1D by reverse transcription-polymerase chain reaction in mouse unfertilized oocytes and preimplantation embryos from zygotes to the blastocyst stage in vivo. Transcripts for 5-HT1B and 5-HT2C serotonin receptors were detected neither in unfertilized oocytes nor at any stages of in vivo developing preimplantation embryos. Serotonin 5-HT1D receptor mRNA was present in unfertilized oocytes, zygotes, 2-cell embryos, compacted morulae and in vivo produced expanded blatocysts. The expression of the mRNA 5-HT1D serotonin receptor was also detected in blastocysts cultured in vitro. When added to the culture medium, specific serotonin 5-HT1D agonist sumatriptan (1 muM) significantly inhibited the development of mouse embryos cultured in vitro. Demonstration of the expression of 5-HT1D serotonin receptor in mouse oocytes and preimplantation embryos supports the idea of a functional serotonin (5-HT1D) receptor in early mammalian development.

Ubiquitination is a universal protein degradation pathway in which the molecules of 8.5-kDa proteolytic peptide ubiquitin are covalently attached to the ε-amino group of the substrate's lysine residues. Little is known about the importance of this highly conserved mechanism for protein recycling in mammalian gametogenesis and fertilization. The data obtained by the students and faculty of the international training course Window to the Zygote 2000 demonstrate the accumulation of ubiquitin-cross-reactive structures in the trophoblast, but not in the inner cell mass of the expanding bovine and mouse blastocysts. This observation suggests that a major burst of ubiquitin-dependent proteolysis occurs in the trophoblast of mammalian peri-implantation embryos. This event may be important for the success of blastocyst hatching, differentiation of embryonic stem cells into soma and germ line, and/or implantation in both naturally conceived and reconstructed mammalian embryos.

Studies of the biochemical properties of MAO-A (monoamine oxidase) are numerous, but the information about determination of MAO-A in human normal and tumour renal tissue is limited. Our objectives in the present study were to determine the localization of MAO-A in normal kidney and level of expression of this protein in tumour kidney. Enzyme immunohistochemical method was chosen for detection of MAO-A in 63 clinical samples of all histopathological types of RCC (renal cell carcinoma). Our results were compared to basic clinical and histopathological parameters such as histopathological type and tumour grade. We also compared MAO-A expression between normal and tumour tissue samples. We confirmed the elevated expression of MAO-A in high-grade tumours of renal cell carcinoma specimens. The percentage of MAO-positive samples progressively increased from 9% in grade 2 to 45% in grade 3. We also noted high levels of MAO-A immunoreactivity in epithelial cells of proximal tubules in normal renal tissue. MAO-A was absent or very low in epithelial cells of distal tubules and glomerular capsule, as well as in endothelial cells of renal vessels. Taken together, our results and findings of other studies show that MAO-A expression in high-grade tumours may have a direct role in maintaining a dedifferentiated phenotype and promoting aggressive behaviour. The ability of clorgyline (an MAO-A inhibitor) to counteract oncogenic pathways and promote differentiation suggests that MAO-A inhibitors, which have been used for many years in clinical practise for treating neurological disorders, could be therapeutic options for advanced stages of tumours.

The study focused on the effect of microwave radiation at a dose which commonly does not lead to tissue heating, however, in the rat testes it resulted in accumulation of heat. Adult rats were exposed to whole body pulse radiation at a frequency of 2.45 GHz and mean power density of 28 W/m ² , for 3 h a day for the duration of 3 weeks. Immediately after each irradiation, the body temperature and the testicular temperature were measured in the control and experimental animals. Samples for histological and immunohistochemical analysis were taken after the last irradiation and processed for light and transmission electron microscopy. An evaluation of spermatozoa motility was performed using computer-assisted sperm analysis. Although the body temperature of the rats was not elevated after the irradiations, the testicular temperature was significantly increased ( P < 0.004). Testes of the experimental animals had considerably dilated and congested blood vessels and the seminiferous epithelium showed degenerative changes. The Leydig cells showed no obvious structural abnormalities. Transmission electron microscopy revealed ultrastructural changes in developing sex cells, Sertoli cells, and endothelial cells. An intensified immunoreactivity to superoxide dismutase 1 was found in spermatogonia and Leydig cells in the experimental animals. Results of the present study revealed a distinctly adverse effect of microwave radiation on the thermoregulatory capability and histological structure of rat testes as well as an oxidative damage of the tissue. The scientific knowledge confirming or denying the thermal effect of microwave radiation on living tissue is scarce and thus the present study may be regarded as unique and helpful to clarify the issue.

This study aimed to examine the relationship between XRCC1, p53 and MDR1 protein, along with polymorphisms of their genes and their prognostic values in breast cancer. The following clinical and pathological parameters were evaluated: histopathological type of tumor, grade, stage, Her2/neu expression, ER, PR positivity and involvement of regional lymph nodes. Expression of proteins was determined in 39 samples of breast cancer by immunohistochemistry. Nucleotide polymorphisms were analyzed by PCR-RFLP. For statistical analysis, chi-square test (Yates), Fisher’s exact test, and correlation test were used to analyze the data. The highest protein expression was immunohistochemically found in MDR1 protein, with 54% of samples testing positive. In addition, the evaluation of MDR1 expression revealed higher positive immunoreactivity in lobular (LIC) and other types of tumor in comparison to ductal (DIC) type. The expression of p53 and XRCC1 protein was equal, but lower compared to MDR1, both testing positive in 36% of all tissue samples. Comparison of XRCC1 protein and histopathological type of tumor revealed that DIC and LIC types were mostly XRCC1-negative, while other types, papillary and mucinous were more likely to be XRCC1-positive. Interestingly, when evaluating LIC samples separately, a negative correlation between the Her2/neu and expression of XRCC1 was detected. Apparently, all Her2/neu-positive samples were XRCC1-negative (6/86%). The correlation test indicated a negative correlation between Her2/neu-positive samples and XRCC1-negative specimens (r=1, p<0.05). Statistical analysis did not reveal a correlation of p53 expression with clinical and pathological parameters. Similarly, no statistically significant difference was found between the tested polymorphisms and protein expression. We did not find statistically significant correlation between tested polymorphisms and their protein expression.