Effect of extenders based on Tris, Tes and skim milk on cryopreservation of epididymal alpaca sperm

El estudio tuvo por objetivo evaluar el efecto de tres dilutores (Tris, Tes y leche descremada) en la criopreservación de espermatozoides obtenidos del epidídimo de alpaca. Previamente se determinó el efecto del tiempo entre el beneficio/castración y la recuperación de los espermatozoides del epidídimo. Se utilizaron 24 testículos de alpacas para la obtención de los espermatozoides directamente del epidídimo en una solución fisiológica buferada (PBS). La recuperación de espermatozoides se realizó a las 0, 35, 48 y 72 horas (6 testículos por grupo) y se evaluó la motilidad, concentración espermática e integridad funcional de membrana. Los espermatozoides recuperados a partir de 35 horas post beneficio/castración no fueron aptos para ser congelados. Las muestras recuperadas a las 0 horas fueron diluidas con Tris, Tes y leche descremada, enfriadas desde 35 a 5 oC en 90 minutos, envasadas en pajillas de 0.25 ml y congeladas en nitrógeno líquido. Se evaluó la motilidad, integridad funcional de membrana y vitalidad/integridad acrosomal en las muestras descongeladas. La motilidad fue de 14.0, 8.6 y 17.0% en los grupos Tris, Tes y leche descremada, respectivamente, donde el grupo leche descremada fue significativamente mejor que el grupo Tes (p<0.05). Los porcentajes de integridad funcional de membrana y vitalidad/integridad acrosomal fueron similares entre los tres grupos. Se concluye que los tres dilutores brindan efectos similares para la criopreservación de espermatozoides epididimarios de alpaca.The objective of this study was to evaluate the effect of three semen extenders (skim milk, Tris, and Tes) on cryopreservation of epididymal alpaca sperm. Previously, the effect of timespan since slaughtering or castration to the recovery of epididymal sperm was evaluated. Twenty-four alpaca testicles were used to obtain sperm from the epididymis in a buffered saline solution (PBS). The recovery of spermatozoa was performed at 0, 35, 48, and 72 hours (6 testes per group) after slaughtering or castration. Sperm motility, concentration, and sperm membrane functional integrity were analyzed. Sperm recovered after 35 hours was not usable for cryopreservation. Sperm samples recovered at 0 hours were subjected to the process of freezing. Samples were diluted with skim milk, Tris, and Tes, cooled from 35 to 5 °C in 90 minutes, packed into 0.25 ml straws and frozen in liquid nitrogen. After thawing, straws were evaluated by motility, sperm membrane functional integrity and vitality/acrosome integrity. Motility was 17.0, 14.0, and 8.6% on skim milk, Tris and Tes groups respectively, where the skim milk group was significantly better than the Tes (p<0.05). Percentages of sperm membrane functional integrity and vitality/acrosomal integrity were similar among the three extenders. It was concluded that all three extenders provided similar effects for the cryopreservation of epididymal alpaca spermatozoa

Reconstructing Native American Population History

The peopling of the Americas has been the subject of extensive genetic, archaeological and linguistic research; however, central questions remain unresolved1–5. One contentious issue is whether the settlement occurred via a single6–8 or multiple streams of migration from Siberia9–15. The pattern of dispersals within the Americas is also poorly understood. To address these questions at higher resolution than was previously possible, we assembled data from 52 Native American and 17 Siberian groups genotyped at 364,470 single nucleotide polymorphisms. We show that Native Americans descend from at least three streams of Asian gene flow. Most descend entirely from a single ancestral population that we call “First American”. However, speakers of Eskimo-Aleut languages from the Arctic inherit almost half their ancestry from a second stream of Asian gene flow, and the Na-Dene-speaking Chipewyan from Canada inherit roughly one-tenth of their ancestry from a third stream. We show that the initial peopling followed a southward expansion facilitated by the coast, with sequential population splits and little gene flow after divergence, especially in South America. A major exception is in Chibchan-speakers on both sides of the Panama Isthmus, who have ancestry from both North and South America

Worldwide trends in hypertension prevalence and progress in treatment and control from 1990 to 2019: a pooled analysis of 1201 population-representative studies with 104 million participants

Background Hypertension can be detected at the primary health-care level and low-cost treatments can effectively control hypertension. We aimed to measure the prevalence of hypertension and progress in its detection, treatment, and control from 1990 to 2019 for 200 countries and territories. Methods We used data from 1990 to 2019 on people aged 30–79 years from population-representative studies with measurement of blood pressure and data on blood pressure treatment. We defined hypertension as having systolic blood pressure 140 mm Hg or greater, diastolic blood pressure 90 mm Hg or greater, or taking medication for hypertension. We applied a Bayesian hierarchical model to estimate the prevalence of hypertension and the proportion of people with hypertension who had a previous diagnosis (detection), who were taking medication for hypertension (treatment), and whose hypertension was controlled to below 140/90 mm Hg (control). The model allowed for trends over time to be non-linear and to vary by age. Findings The number of people aged 30–79 years with hypertension doubled from 1990 to 2019, from 331 (95% credible interval 306–359) million women and 317 (292–344) million men in 1990 to 626 (584–668) million women and 652 (604–698) million men in 2019, despite stable global age-standardised prevalence. In 2019, age-standardised hypertension prevalence was lowest in Canada and Peru for both men and women; in Taiwan, South Korea, Japan, and some countries in western Europe including Switzerland, Spain, and the UK for women; and in several low-income and middle-income countries such as Eritrea, Bangladesh, Ethiopia, and Solomon Islands for men. Hypertension prevalence surpassed 50% for women in two countries and men in nine countries, in central and eastern Europe, central Asia, Oceania, and Latin America. Globally, 59% (55–62) of women and 49% (46–52) of men with hypertension reported a previous diagnosis of hypertension in 2019, and 47% (43–51) of women and 38% (35–41) of men were treated. Control rates among people with hypertension in 2019 were 23% (20–27) for women and 18% (16–21) for men. In 2019, treatment and control rates were highest in South Korea, Canada, and Iceland (treatment >70%; control >50%), followed by the USA, Costa Rica, Germany, Portugal, and Taiwan. Treatment rates were less than 25% for women and less than 20% for men in Nepal, Indonesia, and some countries in sub-Saharan Africa and Oceania. Control rates were below 10% for women and men in these countries and for men in some countries in north Africa, central and south Asia, and eastern Europe. Treatment and control rates have improved in most countries since 1990, but we found little change in most countries in sub-Saharan Africa and Oceania. Improvements were largest in high-income countries, central Europe, and some upper-middle-income and recently high-income countries including Costa Rica, Taiwan, Kazakhstan, South Africa, Brazil, Chile, Turkey, and Iran. Interpretation Improvements in the detection, treatment, and control of hypertension have varied substantially across countries, with some middle-income countries now outperforming most high-income nations. The dual approach of reducing hypertension prevalence through primary prevention and enhancing its treatment and control is achievable not only in high-income countries but also in low-income and middle-income settings

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions

Effect of extenders based on tris, tes and skim milk on cryopreservation of epididymalalpaca sperm [Efecto de dilutores en base a tris, tes y leche descremada en la criopreservaciÓn de espermatozoides obtenidos del epidÍdimo de alpaca]

Se agradece al Consejo Nacional de Ciencia y Tecnología (CONCYTEC) por el financiamiento del presente trabajo a través del Proyecto PROCYT N.°157-2006 «Desarrollo de un protocolo de criopreservación de semen de alpacas mediante el estudio de diferentes dilutores y agentes crioprotectores sobre la funcionalidad espermática».Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte

Diversidad biológica y cultural del sur de la Amazonia colombiana

La gran cuenca amazónica compartida por Brasil, Colombia, Perú, Bolivia, Venezuela, Ecuador y las tres Guyanas, contiene una de las mayores riquezas biológicas y culturales del planeta y es considerada parte de la seguridad ecológica global. Constituye el 45% de los bosques tropicales del mundo, es una de las áreas silvestres más extensas y de mayor reserva de agua dulce del planeta, su sistema hídrico es el mayor tributario de todos los océanos, alberga aún, cerca de 379 grupos étnicos y en cuanto a endemismo, no existe otra región que se le aproxime. En Colombia, la Amazonia a lo largo de la historia ha sufrido distintos procesos de intervención antrópica: la conquista; la colonización; el auge del caucho y la quina; la explotación maderera, petrolera; la implementación de cultivos de uso ilícito y de sistemas productivos no aptos a las condiciones del medio natural; entre otros, son procesos que han socavado tanto los recursos biológicos como los culturales. Conscientes de la problemática actual de la Amazonia así como de la importancia que reviste para el mundo y para el país, la Corporación para el Desarrollo Sostenible del Sur de la Amazonia –Corpoamazonia– y el Instituto de Investigación de Recursos Biológicos Alexander von Humboldt –IAvH-, firmaron en el año 2004 un convenio con el n de aunar esfuerzos para formular el plan de acción en biodiversidad en la región sur de la Amazonia colombiana (departamentos de Caquetá, Putumayo y Amazonas). El plan de acción, busca posicionar la biodiversidad en el desarrollo regional y contribuir a un mayor conocimiento y a unas mejores prácticas de conservación y utilización sostenible de los recursos biológicos y culturales de este importante espacio geográfico. Desarrolla a escala regional, la Política Nacional en Biodiversidad y la Propuesta Técnica de Plan de Acción Nacional en Biodiversidad – Biodiversidad siglo XXI -