To explore the feasibility of transient elastography (TE) to quantify cervical stiffness changes during normal pregnancy and its spatial variability. TE was used to quantify the cervical stiffness in four anatomical regions. 42 women between 17 and 43 years of age and at 6 - 41 weeks of gestation were studied. The stiffness was related to gestational age at the time of examination, interval from ultrasound examination to delivery and cervical length to evaluate the potential of TE to assess cervical ripening. In addition, a sensitivity analysis based on Cronbach's alpha coefficient was carried out to assess the concordance between inter/intra-operator measurements. There were significant correlations between cervical stiffness measured in the four regions with gestational age and the remaining time for delivery. Results confirm stiffness variability within the cervix. No significant association was found between cervical length and stiffness in the four ROIs. Associations between gestational age and remaining time for delivery with cervical length present weaker correlations than with cervical stiffness. The external part of the cervix was significantly softer than the internal one, and these stiffness values vary significantly in the anterior compared to the posterior cervix. The measurements taken by the same and by two different observers for different regions in the cervix were reliable and reproducible. It is feasible to objectively quantify the decrease of cervical stiffness correlated to gestational age. Transient elastography is a valuable promising tool to provide additional information on the process of cervical effacement to that obtained from digital examination and conventional ultrasound. Further studies are needed to assess the feasibility of the technique in obstetric clinical applications, such as prediction of preterm birth or success in labor induction.
Endocannabinoid anandamide and cannabinoid receptors have been described in some organs of the female reproductive system, but little is known about the expression of these receptors in human oocytes. The aim of the study was to describe the expression of cannabinoid receptors in human oocytes and to investigate their differential distribution at various stages of meiotic resumption in human oocytes. A total of 750 human oocytes from 214 patients were analysed by Western blot, immunocytochemistry and PCR. For this study, oocytes that were not suitable for intracytoplasmic sperm injection (ICSI) (germinal-vesicle and metaphase-I stages), as well as metaphase-II oocytes that had not developed into an embryo after ICSI were used. Western blot analysis revealed the presence of CB1 and CB2 receptor proteins in human oocytes. CB1 and CB2 receptor immunostaining patterns changed during the various stages of meiotic resumption. Localization of CB1 receptor was peripheral at germinal-vesicle stage, homogeneous over the entire oocyte at metaphase I and peripheral at mature metaphase II. CB2 receptor localization was peripheral at germinal-vesicle and metaphase-I stages but homogeneous over the entire cell at metaphase II. This finding suggests a possible role for endocannabinoids, acting via receptors, in the maturation of female gametes and fertilization. The number of couples with sterility problems attending fertility programmes is rising but treatment is not always successful. Important problems associated with failure to conceive remain unresolved because many physiological aspects of human reproduction are still unknown. Endocannabinoids are endogenous chemical compounds that mimic the action of the main psychoactive component of marijuana, delta-9-tetrahydrocannabinol. An endogenous cannabinoid named anandamide has been found in human follicular fluid. Thus, in order to develop knowledge in this field, in the present study we have described the presence of the cannabinoid receptors CB1 and CB2 (the proteins required to mediate the action of the cannabinoids) in the early stages of meiotic resumption of oocytes (the stages before ovulation) and we could postulate that the endocannabinoids could act in the regulation of maturation of oocytes. Our study, together with other studies, indicates that the endocannabinoid system may play a role in human reproduction.
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