Usando la curva de tolerancia a la glucosa para calcular el porcentaje relativo de sensibilidad insulínica y el porcentaje relativo de función beta insular / A program to estimate insulin resistance based on data from the oral glucose tolerance test

Background An instrument to help clinicians to evaluate the oral glucose tolerance test (OGTT) at-a-glance is lacking. Aim To generate a program written in HTML squeezing relevant information from the OGTT with glucose and insulin measurements. Material and Methods We reanalyzed a database comprising 90 subjects. All of them had both an OGTT and a pancreatic suppression test (PST) measuring insulin resistance directly. Thirty-seven of the 90 studied participants were insulin resistant (IR). Receiver operating characteristic (ROC) curves and Bayesian analyses delineated the diagnostic performances of four predictors of insulin resistance: HOMA, QUICKI, ISI-OL (Matsuda-DeFronzo) and I0*G60. We validated a new biochemical predictor, the Percentual Relative Insulin Sensitivity (%RIS), and calculated the Percentual Relative Beta Cell Function (%RBCF). Results The best diagnostic performance of the five predictors were those of the I0*G60 and the %RIS. The poorest diagnostic performances were those of the HOMA and QUICKI. The ISI-OL's performance was in between. The %RIS of participants with and without IR was 44.4 ± 7.3 and 101.1 ± 8.8, respectively (p < 0.05). The figures for % RBCF were 55.8 ± 11.8 and 90.8 ± 11.6, respectively (p < 0.05). Mathematical modeling of the relationship between these predictors and the Steady State Plasma Glucose Value from the PST was performed. We developed a program with 10 inputs (glucose and insulin values) and several outputs: I0*G60, HOMA, QUICKI, ISI-OL, Insulinogenic Index, Disposition Index, %RBCF, %RIS, and metabolic categorization of the OGTT (ADA 2003). Conclusions The OGTT data permitted us to write successfully an HTML program allowing the user to fully evaluate at-a-glance its metabolic information.

Crystallization of Bovine Cervical Mucus at Oestrus: An Update / Cristalización del moco cervical bovino en el estro: una actualización / Cristalização do muco cervical bovino no estro: uma atualização

Bovine cervical mucus changes its biochemical composition and biophysical properties due to the variations in sex steroid levels during the oestrous cycle. As a consequence of oestrogen rise, cervical mucus is produced in larger amounts at oestrus-a stage also characterized by an increase in mucus crystallization when observed under light microscopy. The objective of this article is to provide an updated review of the main aspects regarding crystallization of bovine cervical mucus. First, it makes reference to the composition of cervical mucus and the critical functions that this secretion exerts on bovine reproductive physiology, as well as in other species. Then, the article deals with the phenomenon of crystallization observed in cervical mucus, describing the main models used to classify the crystalline patterns observable in mucus at oestrus stage (some of them resembling ferns, palm leaves and stellar patterns, among others). Finally, it addresses the importance of the phenomenon of cervical mucus crystallization for the understanding of bovine reproductive physiology.

El moco cervical bovino cambia su composición bioquímica y sus propiedades biofísicas durante el ciclo estral debido a las variaciones en los niveles de esteroides sexuales, siendo producido en mayor cantidad durante el estro como consecuencia del aumento en el nivel de estrógenos. En dicho estadio también se observa que el moco aumenta su capacidad de cristalizar. El objetivo de este artículo es proporcionar una visión actualizada de los principales aspectos relativos a la cristalización del moco cervical bovino. En primer lugar se hace referencia a la composición del moco y a las importantes funciones ejercidas por esta secreción en la fisiología reproductiva bovina y de otras especies. Más adelante el artículo trata sobre el fenómeno de cristalización observado en el moco cervical en estro, describiéndose los principales modelos utilizados para clasificar los patrones cristalinos observables en él (algunos semejantes a helechos, hojas de palma o figuras estrelladas, entre otros). Finalmente, se discute la importancia del fenómeno de la cristalización del moco cervical para la comprensión de la reproducción bovina tanto en estados fisiológicos así como fisiopatológicos.

O muco cervical bovino varia a sua composição bioquímica e suas propriedades biofísicas durante o ciclo estral devido às variações nos níveis de esteróides sexuais, sendo produzido em maior quantidade durante o estro como consequência do aumento no nível de estrogênios. Neste estado também se observa que o muco aumenta a sua capacidade de cristalizar. O objetivo deste artigo é proporcionar uma visão atualizada dos principais aspectos relativos à cristalização do muco cervical bovino. Em primeiro lugar faz-se referência à composição do muco e das importantes funções exercidas por esta secreção na fisiologia reprodutiva bovina e de outras espécies. Mais adiante o artigo trata sobre o fenômeno de cristalização observado no muco cervical em estro, descrevendo-se os principais modelos utilizados para classificar os padrões cristalinos observáveis no mesmo (alguns semelhantes a samambaias, folhas de palmeira ou figuras estreladas, entre outros). Finalmente, se discute a importância do fenômeno da cristalização do muco cervical para a compreensão da reprodução bovina tanto em estados fisiológicos quanto em fisiopatológicos.

Evidence of Fractality in a Pattern of Crystallization of Bovine Cervical Mucus Obtained at Oestrus / Evidencia de Fractalidad en un Patrón de Cristalización de Moco Cervical Bovino Obtenido en Estro

Fractality has emerged as a feature of the organization of some complex natural systems. Several biological secretions show fractal-like patterns for their crystallization phenomena but their presence in crystallizations of bovine cervical mucus (BCM) is yet unknown. In order to assess the fractality of BCM crystallization, samples of this fluid were taken from heifers at oestrus, their crystalline patterns photographed and its morphology analyzed. Among the many images obtained for BCM crystallizations, one of them had a highly symmetrical geometric arrangement, possessing three zones characterized by pine-like, arboriform structures, evidencing a remarkable similarity between them. Moreover, fractal dimensions obtained for these zones were statistically equal when analyzed by using specialized software. In summary, this brief communication shows, for the first time, that a pattern of crystallization of BCM at oestrus possesses a fractal-like organization.

La fractalidad ha surgido como una característica propia de algunos sistemas biológicos complejos. Varias secreciones biológicas presentan patrones de tipo fractal al cristalizar; no obstante, su presencia en las cristalizaciones de moco cervical bovino aún se desconoce. Con el objetivo de investigar la presencia de fractalidad en las cristalizaciones de moco cervical bovino, se obtuvieron muestras de este fluido de vaquillas en estro, fotografiándose los patrones cristalinos observados. Entre las típicas disposiciones similares a frondas de helechos observadas para la cristalización del moco cervical, se encontró una imagen con un arreglo geométrico altamente simétrico, constando de tres zonas caracterizadas por estructuras arborescentes similares a pinos, muy semejantes entre sí. Más aún, las dimensiones fractales obtenidas para esas zonas fueron estadísticamente iguales al ser dichas áreas analizadas con un programa computacional apropiado. En resumen, esta comunicación breve demuestra por primera vez que uno de los patrones de cristalización de moco cervical bovino en estro está caracterizado por una organización de tipo fractal.

Modulation of spermatozoon acrosome reaction

Spermatozoon acrosome reaction is an exocytotic event of the utmost importance for the development of mammalian fertilisation. Current evidence shows that the triggering of the acrosome reaction (AR) could be regulated by the action of diverse compounds, namely, metabolites, neurotransmitters and hormones. The aim of the present review is to describe the modulating effects of several compounds that have been classified as inductors or inhibitors of acrosome reaction. Among AR inductors, it is necessary to mention progesterone, angiotensin II, atrial natriuretic peptide, cathecolamines, insulin, leptin, relaxin and other hormones. Regarding the inhibitors, oestradiol and epidermal growth factor are among the substances that retard AR. It is worth mentioning that gamma-aminobutyric acid, a neurotransmitter known to be an inhibitor in the central nervous system, has been shown to induce AR. The multiple hormones located in the fluids of the female reproductive tract are also likely to act as subtle regulators of AR, constituting a fundamental aspect for the development of successful fertilisation. Finally, it is necessary to emphasise that the study of regulation exerted by hormones and other compounds on AR is essential for further understanding of mammalian reproductive biology, especially spermatozoon physiology.

In vivo and in vitro estrogenic and progestagenic actions of Tibolone

Estrogen and progestin combination in hormone replacement therapy (HRT) increases the incidence of breast cancer, but decreases the endometrial cancer risk of unopposed estrogen. Therefore, a SERM such as Tibolone, that delivers the beneficial, but not the adverse side effects, of steroid hormones would be clinically advantageous. However, data from the Million Women Study suggests that Tibolone increases the risk of both breast and endometrial cancer. Herein, we assessed the estrogenic and progestagenic actions of Tibolone using transvaginal sonography studies and an in vitro model of breast (ZR-75, MCF7) and endometrial cancer (Ishikawa). The known cancer associated proteins (ER, EGFR, STAT5, tissue factor and Bcl-xL) were selected for study. Transvaginal sonography demonstrated that postmenopausal women treated with Tibolone displayed a thinner endometrium than in the late proliferative phase, but had a phenotype characteristic of the secretory phase, thus demonstrating the estrogenic and progestagenic actions of this SERM. In vitro, Tibolone acted as an estrogen in downregulating ER and upregulating Bcl-xL, yet as progesterone, increasing STAT5 and tissue factor in breast cancer cells. The increase in tissue factor by Tibolone correlated with its coagulative potential. Interestingly, EGFR was up-regulated by progesterone in the breast and by estrogen in endometrial cells, while Tibolone increased protein levels in both cell types. In conclusion, this study further demonstrates the estrogenic and progestagenic nature of Tibolone. The pattern of regulation of known oncogenes in cells of breast and endometrial origin dictates caution and vigilance in the prescription of Tibolone and subsequent patient monitoring.

Evaluación de la capacidad fértil del espermatozoide humano / Evaluation of the fertil capacitation of human spermatozoa

El espermatozoide humano sufre una serie de cambios antes de ser capaz de fecundar un ovocito. Estos cambios pueden dividirse en capacitación, hiperactivación, reacción del acrosoma y fusión de las membranas gaméticas. El análisis del semen de rutina da poca información acerca de la capacidad del espermatozoide de experimentar estos cambios. El bioensayo de penetración del ovocito de criceto es una prueba optativa que puede ser usada con el objeto de analizar la capacidad fértil del espermatozoide humano. Se ha demostrado que existe correlación entre este bioensayo de fusión de membranas gaméticas heterólogas y la fecundación in vivo e in vitro. La presente revisión analiza los materiales y métodos utilizados para llevar a cabo esta prueba, y brinda información respecto a su aplicación en el tratamiento de la pareje infértil