In vitro assessment of some sperm function following exposure to levonorgestrel in human fallopian tubes.

BACKGROUND: The mechanism of action of levonorgestrel (LNG) as emergency contraception (EC) remains a subject of debate and its effect on sperm function has been only partially explained. The aim of this study was to assess whether LNG at a similar dose to those found in serum following oral intake for EC could affect spermatozoa when exposed to human fallopian tubes in vitro. METHODS: Fifteen mini-laparotomies were performed, the side on which ovulation occurred was recorded, and both tubes were removed and perfused with a suspension containing 1 × 10(6) motile spermatozoa, with or without LNG. Following 4-hour incubation, the tubes were sectioned to separate the isthmus and the ampulla. Each segment was flushed and the material was evaluated to quantify the number of motile sperm, the number of spermatozoa adhering to the oviductal epithelium and the acrosome reaction (AR) rate. RESULTS: The addition of LNG did not significantly alter the number of recovered motile spermatozoa either at the isthmus or at the ampulla, nor did it have any effect on the number of recovered spermatozoa adhered to the human tubal epithelium. Furthermore, LNG did not affect the AR rate. No significant differences were found even when the side on which ovulation occurred was taken into account. CONCLUSIONS: In a similar dose to that observed in serum following oral intake for EC, LNG had no effect on the number of motile spermatozoa recovered from the human fallopian tubes in vitro, on their adhesion to the tubal epithelium, distribution or AR rate. The possible effect of LNG as EC on sperm function remains poorly understood.

Copper-T intrauterine device and levonorgestrel intrauterine system: biological bases of their mechanism of action.

All intrauterine devices (IUDs) that have been tested experimentally or clinically induce a local inflammatory reaction of the endometrium whose cellular and humoral components are expressed in the tissue and the fluid filling the uterine cavity. Depending on the reproductive strategy of the species considered and the anatomical features and physiologic mechanisms that characterize their reproductive system, the secondary consequences of this foreign body reaction can be very localized within the uterus, as in the rabbit, or widespread throughout the entire genital tract as in women or even systemic as in some farm animals. Levonorgestrel released from an IUD causes some systemic effects, but local effects such as glandular atrophy and stromal decidualization, in addition to the foreign body reaction, are dominant. Copper ions released from an IUD enhance the inflammatory response and reach concentrations in the luminal fluids of the genital tract that are toxic for spermatozoa. In the human, the entire genital tract appears affected due to luminal transmission of the noxa that accumulates in the uterine lumen. This affects the function and viability of gametes, decreasing the rate of fertilization and lowering the chances of survival of any embryo that may be formed, before it reaches the uterus. The bulk of the data indicate that if any embryos are formed in the chronic presence of an IUD, it happens at a much lower rate than in non-IUD users. The common belief that the usual mechanism of action of IUDs in women is destruction of embryos in the uterus is not supported by empirical evidence.

Transmembrane and truncated (SEC) isoforms of MUC1 in the human endometrium and Fallopian tube.

The cell surface mucin MUC1 is expressed by endometrial epithelial cells with increased abundance in the secretory phase of the menstrual cycle, when it is found both at the apical cell surface and in secretions. This suggests the presence of a maternal cell surface glycoprotein barrier to embryo implantation, arising from the anti-adhesive property of MUC1. In previous work, we demonstrated alternatively spliced MUC1 variant forms in tumour cells. The variant MUC1/SEC lacks the transmembrane and cytoplasmic sequences found in the full-length variant. We now show that MUC1/SEC mRNA is present in endometrial carcinoma cell lines, endometrial tissue and primary cultured endometrial epithelial cells. The protein can be detected using isoform-specific antibodies in uterine flushings, suggesting release from endometrium in vivo. However, on the basis of immunolocalisation studies, MUC1/SEC also remains associated with the apical epithelial surface both in tissue and in cultured cells. Transmembrane MUC1 and MUC1/SEC are both strikingly localised to the apical surface of tubal epithelium. Thus MUC1 may contribute to the anti-adhesive character of the tubal surface, inhibiting ectopic implantation. The mechanism by which this barrier is overcome in endometrium at implantation is the subject of ongoing investigation.

Concanavalin-A induces granulosa cell death and inhibits FSH-mediated follicular growth and ovarian maturation in female rats.

Reproductive success stems from a finely regulated balance between follicular maturation and atresia, in which the role of carbohydrate structure is poorly understood. Here, we describe for the first time a fraction of purified recombinant human FSH that is capable of bringing about the cell death of granulosa cells and preventing follicular maturation in a rat model. Further analysis by mass spectrometry revealed the presence of the lectin Concanavalin-A (Con-A) within this fraction of recombinant FSH. Using both the fractionated FSH and Con-A, the observed cell death was predominantly located to the granulosa cells. Ex vivo culture of rat follicles demonstrated that follicle degeneration occurred and resulted in the release of a denuded and deteriorated oocyte. Moreover, in vivo experiments confirmed an increase in atresia and a corresponding reduction confined to follicle in early antral stage. As a mechanism of action, Con-A reduces ovarian proliferation, Von Willebrand staining, and angiogenesis. Based on the observation that Con-A may induce granulosa cell death followed by follicle death, our results further demonstrate that follicular carbohydrate moiety is changing under the influence of FSH, which may allow a carbohydrate-binding lectin to increase granulosa cell death. The physiological consequences of circulating lectin-like molecules remain to be determined. However, our results suggest a potential exploitation of carbohydrate binding in fertility and ovarian cancer treatment. This work may shed light on a key role of carbohydrates in the still obscure physiological process of follicular selection and atresia.

Differentiation in the mouse morulae.

A cytochemical method has been used to test claims that the differentiation of the mouse morulae can be accounted for by the position of the blastomeres: the central becoming inner mass cells and the peripheral trophoblast cells. The cytochemical method is an adaptation of Gomori-Takamatsu's demonstration of alkaline phosphatase activity, which stains the inner cell mass and not the trophoblast. The significance of this procedure is dicussed. A simple physical model shows that by packing spheres of similar size, at least 17 are needed to have one completely enclosed. On these basis, if the position is the decisive factor, alkaline phosphatase activity should be detected in embryos with more than 17 cells. Table 1 shows that it is a correct assumption. But since blastomeres that have gone through more cell cycles are smaller and have a better chance of reaching a central position, it became necessary to dissociate number of cells from number of cell cycles. This we did by detecting the appearance of the enzyme activity in halved and fused embryos developedin vitro. Table 2 shows that the activity is detected in halved embryos from the 11-cell stage onwards. Table 3 shows that it is detected in fusion embryos from the 22-cell stage onwards. The results suggest that a temporal coordinate, the number of cell cycles or another temporal change, might interact with the spatial coordinate to produce differentiation.

Aplicación de medidas preventivas en adultos mayores de acuerdo al programa integrado de salud (PREVENIMSS) / Performance of preventive measures in elderly population according to health integrated program (PREVENIMSS)

Objetivo: Evaluar la aplicación de acciones preventivas del Programa Integrado de Salud (PREVENIMSS) en adultos de 60 años y más de la Zona Metropolitana de Monterrey, Nuevo León. Metodología: Se revisaron 384 expedientes de adultos mayores (60 años y más) de cuatro unidades médicas. La aplicación de esquemas se midió a través de la frecuencia y periodicidad de las acciones de inmunización y detección, con los siguientes indicadores: aplicación recomendada, menos de lo recomendado, más de lo recomendado y no hay registro, se incluyeron las vacunas antineumocóccica (VAN), antiinfluenza (VAI) y toxoide tetánico diftérico (TTD); detección de diabetes mellitus (DDM), hipertensión arterial (DHTA), cáncer mamario (DCAMA) y cáncer cérvico uterino (DCACU). La información se recabó en una ficha de colección de datos diseñada para este fin. El análisis se realizó con estadística descriptiva. Resultados: La VAI se aplicó de acuerdo a lo recomendado en 2.6%, VAN 16.1% y TTD 30.2%. En DDM 30.6%, DHTA 42.1%, DCAMA 20.8% y DCACU 34.2%. Conclusiones: Las acciones de detección PREVENIMSS se aplicaron en menos de la mitad de la población, mientras que las de vacunación fueron de 3 a 30% de los adultos mayores. Trabajos como éste son fuente importante de datos que ayudan a la evaluación de programas.

Objective: To evaluate the performance of preventive actions in the Health Integrated Program (PREVENIMSS) in elder of 60 years and older in the metropolitan zone of Monterrey, Nuevo Leon. Methodology: 384 older people's charts (60 years old and older) from four medical units were reviewed. Performance of schemes was measured through frequency and length of measures of immunization and detection with the following indicators: recommended action, less than recommended action, more than recommended action, and no-record; vaccines that were included are Pneumovaccine (VAN), Flu vaccine (VAI), and titanicdiphtheria toxoid (TTD), besides the detection of Diabetes Mellitus (DDM), high blood pressure (DHTA), breast cancer (DCAMA), and cervical-uterus cancer (DCACU). Information was gathered in a collecting data card designed for this goal. Analysis was done with descriptive statistics. Results: VAI was performed according to recommended in 26%; VAN 16.1%; and TTD 30.2%.For DDM 30.6; DHTA 42.1%; DCAMA 20.8%; and DCACU 34.2%. Conclusions: The actions for detection from PREVENIMSS were performed in less than a half of population; meanwhile, vaccinations went from 3 to 30% in elderly people. Performances like this are important source of data to help in evaluation of programs.