Injertos osteocondrales congelados en el conejo: Estudio experimental

Con el propósito de analizar un protocolo de congelación de cartílago completo estudiando y la viabilidad del cartílago tas la implantación se ha realizado un estudio experimental en 60 rodillas de 45 conejos de Nueva Zelanda en población no genéticamente pura. Se extrajeron injertos osteocartilaginosos de 4 mm de diámetro y 2-3 mm de espesor, incluyendo cartílago articular y hueso subcondral que fueron sometidos a congelación lenta hasta -196º en Planer Kryo-10, Serie II, Controlled Rate Freezers, siguiendo un descenso de temperatura controlada bajo crioprotección con Dimetilsulfóxido, propanodiol y sacarosa. Posteriormente fueron descongelados e implantados en cóndilos femorales. Los injertos evolucionaron a tejido amorfo acelular y pasados los 2 meses, tras la incorporación del componente óseo se desarrolló tejido ibrocartilaginoso de sustitución. El presente estudio indica que el cartílago articular congelado no mantiene su viabilidad tras la implantación.The purpose of this study was to analyze a protocol for freezing whole cartilage and to study the viability of cartilage after the implant in 60 knees of 45 New Zealand rabbits from a genetically impure population. Osteocartilaginous implants were removed, measuring 4 mm in diameter and 2-3 mm thickness, inclunding the articular cartilage and the suchondral bone, and slow freezing up -196º using Planer Kyro-10, Series II, Controlled Rate Freezers, following a controlled drop in temperature under cyrso-protection with Dimethylsulfoxide, propanediol and sacarose. After thawing grafts were implanted in femoral condyles. The implants evolves into an acellular amorphous tissue and after 2 months, period in which the incorporation of the osseous compound occurs, substitute fibrocartilaginous tiusse develops. This study shows that frozen articular cartilage does not remain viable after implant

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

Diminishing benefits of urban living for children and adolescents’ growth and development

Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight

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