Oral Sex as a Potential Route for Toxoplasma Gondii Transmission: Experiment with Human Semen and Laboratory Mice Model.

PURPOSE: Toxoplasma gondii is one of the most widespread parasites in the human population globally. Several modes of its transmission have been proposed: some are well-researched and confirmed, others remain unconfirmed. One unconfirmed hypothesis pertains to potential transmission of Toxoplasma gondii via oral sex (fellatio) in humans. A recent study found tissue cysts in the semen of men with latent toxoplasmosis. Therefore, we aimed to test the hypothesis of Toxoplasma gondii transmission through oral sex experimentally. METHODS: Eighty-two laboratory mice were orally administered semen samples from 41 men with latent toxoplasmosis. These semen samples were examined for the presence of Toxoplasma gondii DNA using PCR. RESULTS: We detected Toxoplasma gondii DNA in three of the 41 semen samples from men with latent toxoplasmosis. Oral administration of semen samples to laboratory mice did not result in parasite transmission. CONCLUSION: We have not demonstrated the transmission of Toxoplasma to mice by oral exposure to semen from infected men. While this does not conclusively rule out the possibility of such transmission in humans, the results suggest that, if it does occur, this mode of transmission is likely infrequent.

Assisted reproduction - principles, procedures, and their effectiveness.

Assisted reproduction is an integral part of infertility treatment. The basic method is in vitro fertilisation (IVF), and intracytoplasmic sperm injection into the oocyte, cryopreservation of sperm, oocytes and embryos is also commonly used. The proportion of embryos tested with preimplantation genetic testing (PGT) for chromosomal aneuploidy or defects in specific genes is increasing. The use of donated oocytes is also significant, particularly because of the depletion of ovarian reserve in women over 40 years of age. The effectiveness of treatment is always very fundamentally dependent on the age of the woman. Assisted reproductive treatment is very well available in the Czech Republic, as is fertility preservation by sperm/oocyte freezing.

Timing of ICSI with Respect to Meiotic Spindle Status.

The aim of this study was to evaluate the efficiency of using meiotic spindle (MS) visibility and relative position to the polar body (PB) as indicators of oocyte maturation in order to optimize intracytoplasmic sperm injection (ICSI) timing. This was a cohort study of patients younger than 40 years with planned ICSI, the timing of which was determined by MS status, compared with those without MS evaluation. The angle between PB and MS and MS visibility were evaluated by optical microscope with polarizing filter. Oocytes with MS evaluation were fertilized according to MS status either 5-6 h after ovum pick-up (OPU) or 7-8 h after OPU. Oocytes without MS evaluation were all fertilized 5-6 h after OPU. For patients over 35 years visualization of MS influenced pregnancy rate (PR): 182 patients with MS visualization had 32% PR (58/182); while 195 patients without MS visualization had 24% PR (47/195). For patients under 35 years, visualization of MS did not influence PR: 140 patients with MS visualization had 41% PR (58/140), while 162 patients without MS visualization had 41% PR (66/162). Visualization of MS therefore appears to be a useful parameter for assessment of oocyte maturity and ICSI timing for patients older than 35.

Important parameters affecting quality of vitrified donor oocytes.

For group of 281 oocytes obtained from 43 stimulated donors and cryopreserved by vitrification protocol using Cryotop and Kitazato medium we determined important parameters of oocytes collection and vitrification processes which strongly affect the probability that warmed oocytes will produce high-quality embryos for transfer. The probability to obtain high-quality embryos for transfer from vitrified and warmed oocytes was highest when two conditions were fulfilled: 1. oocytes were incubated before vitrification for 7-10 h and 2. stimulated ovaries of donors in one cycle produced a smaller number of oocytes (<7 oocytes from one donor per stimulated cycle). The probable reasons for these observations were: 1. early vitrification (less than 7 h) before final oocyte metaphase II maturation negatively affected the crucial process of post-warm remodelling of spindles and chromosomes, which reduced the fertilization and utilization rates, 2. the evaluated vitrification protocol amplifies negative impact of membrane defects of oocytes of those cohorts containing more than 6 oocytes - freezing places great demands on the integrity and elasticity of the cell membranes. The fact that cryopreservation influences a complex state of oocytes was confirmed by confocal microscopy.

Effect of polychlorinated biphenyls (PCBs) and 1,1,1-trichloro-2,2,-bis (4-chlorophenyl)-ethane (DDT) in follicular fluid on the results of in vitro fertilization-embryo transfer (IVF-ET) programs.

OBJECTIVE: To establish the effect of chlorinated organic compounds on fertility. DESIGN: We analyzed the influence of polychlorinated biphenyls (PCBs) and pesticides in follicular fluid on the number of fertilized oocytes, the quality of oocytes and embryos, pregnancy rate, and number of embryos cryoconserved in IVF-ET program. SETTING: Department of Gynecology and Obstetrics, Charles University, First Faculty of Medicine and General Teaching Hospital, Prague, Czech Republic. PATIENT(S): Patients from the Center of Assisted Reproduction. INTERVENTION(S): We collected the follicular fluid of 99 infertile women. MAIN OUTCOME MEASURE(S): The levels of xenobiotics in follicular fluid were examined by high-resolution mass spectrometry and gas chromatography. Correlations between the levels of xenobiotics and IVF-ET program results were statistically analyzed. RESULT(S): The PCB levels varied from 0.1 to 254.6 ng/g of fat. Levels of DDT and its metabolites varied from 0.3 to 35 228.8 ng/g of fat. A correlation was found between the number of diploid oocytes and the level of DDT, the fertilization of oocytes and level of PCB 158, and the pregnancy rate and the number of embryos cryoconserved and levels of PCB 47. CONCLUSION(S): Xenobiotics can be detected in the fat compartment of the follicular fluid. Some correlation to the IVF-ET program results was established, to a degree that might be considered of concern, although it was not statistically significant at the 5% level.