The Mexican View on the Operation of NAFTA for the Resolution of Canada-U.S.-Mexico Disputes

Mexico and NAFTA dispute resolution--Canada and United State

The effect of nutrition and metabolic hormones on follicular development in cattle

Nutrition has profound effects on reproductive performance in cattle. Although these effects have been documented, the underlying mechanisms are not yet fully understood. The aim of this project was to investigate the role of metabolic hormones in mediating these nutritional effects by studying bovine folliculogenesis. The interaction of metabolic hormones and gonadotrophins on granulosa cell function in vitro was also investigated.To determine the effect of nutrition on ovarian follicular development, twenty -eight heifers were allocated to different dietary treatments. Small follicle number ( 8mm) follicles and FSH concentrations were not different among treatments.The relationship between postpartum follicular development and endocrine and metabolic changes in lines selected for high or low predicted breeding value for milk yield (PBV) was investigated. PBV was strongly correlated with milk production during a 305 day -lactation. This was associated with higher peripheral GH and ß- hydroxybutyrate, and lower insulin and glucose concentrations in high genetic merit cows. Although no differences were seen in follicular development between selection lines, changes in body weight influenced follicle number, and day to first ovulation postpartum was delayed in cows selected for high milk production.To gain an insight into the mechanisms underlying the nutritional effect on folliculogenesis, a serum -free bovine granulosa cell culture system was developed. In the presence of FSH, granulosa cells from small follicles differentiated in vitro and oestradiol (E,) secretion increased with time. Cells from medium -sized and large follicles secreted E2 throughout the culture period. Insulin and FSH promoted proliferation and E, production in a dose -responsive manner. The inclusion of IGF -I enhanced proliferation and E, production, even in the absence of FSH. Furthermore, cultured granulosa cells formed clumps of spherical cells with ultrastructural characteristics that resembled those of granulosa cells in vivo. In contrast, granulosa cells growing either in the base of the clump, or as monolayers on serum- coated wells, possessed morphological characteristics suggestive of early luteinisation.The interaction of IGF -I and insulin on granulosa cell proliferation and E, production in vitro was determined in cells from follicles from cattle without or with a dominant follicle in vivo, i.e. ovaries were collected either on day 3 or day 7 of the oestrous cycle respectively. E, production and proliferative capacity of granulosa cells from medium -sized follicles in vitro was inhibited by the presence of a dominant follicle during their development in vivo. However, after long -term culture, E, production did not differ between granulosa cells either from day 3 or from day 7 follicles, but there were differences in proliferative responses to FSH and IGF -I according to the size of the follicle and the stage of the follicular wave.The effects of FSH, EGF and IGF -I on early follicular development were studied by culturing preantral follicles. Follicle and oocyte diameter increased with time in culture. FSH, IGF -I and EGF stimulated follicle growth, but not oocyte growth rate. Most follicles maintained their morphology throughout culture and antra developed after 10 to 28 days of culture. EGF, IGF -I and FSH increased the probability of antrum developmentThese results demonstrate that insulin and IGF -I, but not GH, may mediate the direct effects of nutrition on follicular development. IGFs may also have an autocrine action in the follicle, being tightly regulated by the production of IGF -BPs within the follicle.IGFs, as mediators of steroidogenesis and proliferation of granulosa cells, can act through endocrine, autocrine and/or paracrine mechanisms. Neither insulin nor FSH induced detectable levels of IGF -I production in granulosa cells, but IGF- binding proteins were secreted. IGF -I mRNA expression was found in theca cells, but not in granulosa cells either before or after culture. In contrast, IGF -II was expressed in both theca and granulosa cells

Green fluorescent protein as an indicator of cryoinjury in tissues.

The fluorescence intensity of Green Fluorescent Protein (GFP) has previously been demonstrated to be an accurate indicator of cellular viability following cryoinsult in individual GFP-transfected cells. In an attempt to ascertain whether GFP fluorescence intensity may also be used as a viability indicator following cryogenic insults in whole tissues, this study examines the transient fluorescence intensity of GFP-transfected mouse hepatic tissue ex vivo following cryoinsult. The observed trends are compared with diffusion-based models. It was observed that the fluorescence intensity of the exposed tissues exhibited slow exponential decay, while the solution in which the tissues were placed inversely gained fluorescence. This slow decay (~3 h) is in contrast to the rapidly diminished fluorescence intensity (seconds) seen in GFP-cell cultures following cryoinsult. These trends suggest that mass diffusion of GFP in the interstitial space, and ultimately into the surrounding medium, is the primary mechanism which determines the fluorescence loss in cryoinjured tissues. These results suggest GFP-transfected tissues may be effectively used as indicators of cryoinjury, and hence viability, following hypothermal insult provided that a sufficiently long incubation is held before observation. It was found that a meaningful observation (15% reduction in fluorescence) could be made three hours subsequent to cryoinjury for the tissues used in this study

Inflammatory response to implantation of transparent nanocrystalline yttria-stabilized zirconia using a dorsal window chamber model.

The long-range goal of the windows to the brain (WttB) is to improve patient care by providing a technique for delivery and/or collection of light into/from the brain, on demand, over large areas, and on a chronically-recurring basis without the need for repeated craniotomies. To evaluate the potential of nanocrystalline yttria-stabilized-zirconia (nc-YSZ) cranial implant for optical therapy and imaging, in vivo biocompatibility was studied using the dorsal window chamber model in comparison with control (no implant) and commercially available cranial implant materials (PEEK and PEKK). The host tissue response to implant was characterized by using transillumination and fluorescent microscopy to measure leukocyte adhesion, blood vessel diameter, blood flow rate, and vascular permeability over two weeks. The results indicated the lack of inflammatory reaction of the host tissue to nc-YSZ at the microscopic level, suggesting that nc-YSZ is a good alternative material for cranial implants

Evaluation of laser bacterial anti-fouling of transparent nanocrystalline yttria-stabilized-zirconia cranial implant.

Background and objectiveThe development and feasibility of a novel nanocrystalline yttria-stabilized-zirconia (nc-YSZ) cranial implant has been recently established. The purpose of what we now call "window to the brain (WttB)" implant (or platform), is to improve patient care by providing a technique for delivery and/or collection of light into/from the brain, on demand, over large areas, and on a chronically recurring basis without the need for repeated craniotomies. WttB holds the transformative potential for enhancing light-based diagnosis and treatment of a wide variety of brain pathologies including cerebral edema, traumatic brain injury, stroke, glioma, and neurodegenerative diseases. However, bacterial adhesion to the cranial implant is the leading factor for biofilm formation (fouling), infection, and treatment failure. Escherichia coli (E. coli), in particular, is the most common isolate in gram-negative bacillary meningitis after cranial surgery or trauma. The transparency of our WttB implant may provide a unique opportunity for non-invasive treatment of bacterial infection under the implant using medical lasers.Study design/materials and methodsA drop of a diluted overnight culture of BL21-293 E. coli expressing luciferase was seeded between the nc-YSZ implant and the agar plate. This was followed by immediate irradiation with selected laser. After each laser treatment the nc-YSZ was removed, and cultures were incubated for 24 hours at 37 °C. The study examined continuous wave (CW) and pulsed wave (PW) modes of near-infrared (NIR) 810 nm laser wavelength with a power output ranging from 1 to 3 W. During irradiation, the temperature distribution of nc-YSZ surface was monitored using an infrared thermal camera. Relative luminescence unit (RLU) was used to evaluate the viability of bacteria after the NIR laser treatment.ResultsAnalysis of RLU suggests that the viability of E. coli biofilm formation was reduced with NIR laser treatment when compared to the control group (P < 0.01) and loss of viability depends on both laser fluence and operation mode (CW or PW). The results demonstrate that while CW laser reduces the biofilm formation more than PW laser with the same power, the higher surface temperature of the implant generated by CW laser limits its medical efficacy. In contrast, with the right parameters, PW laser produces a more moderate photothermal effect which can be equally effective at controlling bacterial growth.ConclusionsOur results show that E. coli biofilm formation across the thickness of the nc-YSZ implant can be disrupted using NIR laser treatment. The results of this in vitro study suggest that using nc-YSZ as a cranial implant in vivo may also allow for locally selective, non-invasive, chronic treatment of bacterial layers (fouling) that might form under cranial implants, without causing adverse thermal damage to the underlying host tissue when appropriate laser parameters are used. Lasers Surg. Med. 48:782-789, 2016. © 2016 Wiley Periodicals, Inc

Prevalencia de anticuerpos contra Toxoplasma gondii en mujeres gestantes atendidas en el puesto de salud Miguel Grau del distrito El Porvenir - Trujillo 2016

El presente trabajo se trata de un estudio de corte transversal para determinar la prevalencia de infección por Toxoplasma gondii en mujeres gestantes atendidas en el Puesto de Salud ‘’Miguel Grau del distrito El Porvenir – Trujillo 2016, se determinó la relación causa-efecto en 39 mujeres gestantes mediante la detección de anticuerpos séricos a toxoplasmosis utilizando la prueba de Inmunofluorescencia Indirecta (IFI). La seroprevalencia fue de 54% (21∕39) para IgG, la prueba de Chi Cuadrado determinó significancia entre las gestantes considerando la tenencia de mascota y antecedentes de aborto como factores de riesgo; no existiendo una relación con el estilo de vida y nivel socioeconómico.The present study is a cross-sectional study to determine the prevalence of Toxoplasma gondii infection in pregnant women treated at the Miguel Grau Health Post in the El Porvenir district of Trujillo in 2016. The cause-effect relationship was determined in 39 Pregnant women by detecting serum antibodies to toxoplasmosis using the Indirect Immunofluorescence Test (IFI). The seroprevalence was 54% (21/39) for IgG, the Chi Square test determined significance among pregnant women considering pet ownership and history of abortion as risk factors; Not having a relationship with the lifestyle and socioeconomic level. .Tesi

Diseño e implementación de un sistema para el reconocimiento de patrones utilizando videocámaras

El continuo desarrollo de la sociedad y en especial el sector industrial cada vez es más competitivo y exigente. La demanda de productos en todos los sectores exige que los productos adquiridos cumplan siempre con estándares de calidad que garanticen el mejor desempeño, funcionalidad y satisfacción. La gran demanda de productos, hace que sea común encontrar en las líneas de producción el manejo de diferentes productos, lo que genera que las metodologías de reconocimiento aplicadas a los sistemas de identificación, no funcionen en algunos de estos ambientes. Para cumplir con el estándar anterior, la industria implementa metodologías que permiten identificar cualquier irregularidad en los productos fabricados u ofrecidos. La etapa del reconocimiento de patrones es realizado en ocasiones por personal calificado mediante la inspección manual y visual a cada producto, siendo este un método no eficiente y de baja rigurosidad que puede presentar errores y disminuir la efectividad en los procesos debido al agotamiento físico, perdida de atención y criterios subjetivos del ser humano [1, 2, 3]. Con el objetivo de mejorar este proceso, se ha implementado sistemas de reconocimiento automático mediante el uso de vídeo cámaras y técnicas de visión por computadora, el cual permita combinar y realizar una fusión de datos entregados por diferentes descriptores, los cuales permiten reconocer cambios de color, forma y textura presentes en un objeto. Tales cambios son de vital importancia y permiten definir modelos matemáticos para detección de patrones, como hendiduras, rayones, golpes, cambios de forma, etc. [2, 4, 5, 6, 7]