Effect of Mineral Supplementation on the Macromineral Concentration in Blood in Pre- and Postpartum Blackbelly Sheep.

The objective of this study was to determine the effect of mineral supplementation on the serum concentration of calcium, phosphorus, and magnesium in pre- and postpartum Blackbelly sheep throughout three successive lambing periods under free grazing conditions in the Ecuadorian Amazon Region. The field work was carried out between January 2015 and February 2018 using 20 Blackbelly sheep belonging to the Centre for Research, Postgraduate Studies and Conservation of Amazon Biodiversity, Ecuador. The flock was randomly divided into two groups: Group 1 (G1) was fed with forage plus a supplementation (Pecutrin® Mineral supplement plus vitamins A, D3, and E. Bayer HealthCare) and Group 2 (G2) was fed only with forage without mineral supplementation. Three blood samples from the coccygeal vein were taken from each sheep 30 days before lambing, 30 days after, and 60 days after lambing. Concerning the average of calcium, significant differences were found at different times inside each group and also between them (p < 0.0001 in both cases). As for the phosphorus, significant differences were found between the means of the groups for all times from 30 days after the second lambing season (p < 0.05). It was observed that the groups differed significantly in terms on the average of magnesium (considering a significance level of 0.05) 30 days before the first lambing and at all times measured from the 30 days after the second lambing (p < 0.005). In this study, we showed that Blackbelly sheep raised under free grazing conditions in the Ecuadorian Amazon Region had very low serum calcium values, and supplementation was unable to improve them. Meanwhile, phosphorus and magnesium levels were below the required values, but after supplementation, they exceeded the minimum threshold. Mineral supplementation in the rearing of sheep in grazing systems is necessary during the entire production cycle, but it must be done taking into account the soil-plant-animal relationship specifically for the Amazonian Region systems.

The median eminence as the hypothalamic area involved in rapid transfer of glucose to the brain: functional and cellular mechanisms.

Our data proposes that glucose is transferred directly to the cerebrospinal fluid (CSF) of the hypothalamic ventricular cavity through a rapid "fast-track-type mechanism" that would efficiently stimulate the glucosensing areas. This mechanism would occur at the level of the median eminence (ME), a periventricular hypothalamic zone with no blood-brain barrier. This "fast-track" mechanism would involve specific glial cells of the ME known as ß2 tanycytes that could function as "inverted enterocytes," expressing low-affinity glucose transporters GLUT2 and GLUT6 in order to rapidly transfer glucose to the CSF. Due to the large size of tanycytes, the presence of a high concentration of mitochondria and the expression of low-affinity glucose transporters, it would be expected that these cells accumulate glucose in the endoplasmic reticulum (ER) by sequestering glucose-6-phosphate (G-6-P), in a similar way to that recently demonstrated in astrocytes. Glucose could diffuse through the cells by micrometric distances to be released in the apical region of ß2 tanycytes, towards the CSF. Through this mechanism, levels of glucose would increase inside the hypothalamus, stimulating glucosensing mechanisms quickly and efficiently. KEY MESSAGES: • Glucose diffuses through the median eminence cells (ß2 tanycytes), towards the hypothalamic CSF. • Glucose is transferred through a rapid "fast-track-type mechanism" via GLUT2 and GLUT6. • Through this mechanism, hypothalamic glucose levels increase, stimulating glucosensing.

Comparative strength and dendritic organization of thalamocortical and corticocortical synapses onto excitatory layer 4 neurons.

Thalamus is a potent driver of cortical activity even though cortical synapses onto excitatory layer 4 neurons outnumber thalamic synapses 10 to 1. Previous in vitro studies have proposed that thalamocortical (TC) synapses are stronger than corticocortical (CC) synapses. Here, we investigated possible anatomical and physiological differences between these inputs in the rat in vivo. We developed a high-throughput light microscopy method, validated by electron microscopy, to completely map the locations of synapses across an entire dendritic tree. This demonstrated that TC synapses are slightly more proximal to the soma than CC synapses, but detailed compartmental modeling predicted that dendritic filtering does not appreciably favor one synaptic class over another. Measurements of synaptic strength in intact animals confirmed that both TC and CC synapses are weak and approximately equivalent. We conclude that thalamic effectiveness does not rely on enhanced TC strength, but rather on coincident activation of converging inputs.

Cetoacidosis diabética grave: tratamiento / Severe diabetic ketoacidosis: treatment

El tratamiento de la cetoacidosis diabética grave incluye: hidratación, insulina, reposición de electrólitos y soluciones alcalinizantes. La hidratación se inicia con solución salina isotónica, 1.000 ml por hora en las primeras tres horas, disminuyendo luego el ritmo de infusión, según respuesta clínica; cuando la glicemia desciende a 250 mg/dl se continúa con solución glucosada al 5% hasta completar las primeras 24 horas. La insulinoterapia se realiza con dosis bajas de insulina cristalina, existiendo tres sistemas para su administración: infusión endovenosa continua con bomba, bolos endovenosos horarios e inyecciones vía intramuscular horaria, cuyos resultados son igualmente efectivos y seguros. Nosotros empleamos el esquema intramuscular horario por su mayor facilidad de manejo; se recomienda una dosis inicial de 5 U. e.v. y 5 U. i.m., seguida de 5 U. i.m. por hora, hasta lograr glicemia cercana a 250 mg/dl, en que se prosigue con 5-10 U. subcutánea cada 6 horas, segun controles de glicemias. La reposición de electrólitos se refiere fundamentalmente a la administración de potasio, en dosis de 30 a 40 mEq por cada 1.000 ml de infusión a partor del segundo litro de hidratación, completando 100 a 140 mEq en las primeras 24 horas. El uso de soluciones alcalinizantes actualmente se reserva sólo para los casos con pH inferior a 7,1 o HCO3- bajo 10 mEq/1, recomendándose una dosis de 50 a 100 mM de bicarbonato de sodio a pasar en 30 a 60 minutos. La transición al tratamiento habitual incluye la alimentación oral que se reinicia cuando el sujeto está consciente y sin vómitos, en forma de régimen líquido fraccionado; la insulina cristalina se mantiene por 48 horas, 5-15 U. subcutánea cada 6 a 8 hrs., pasando luego a insulina de acción intermedia en la dosis previa al episodio agudo o 1/2 a 2/3 de la dosis total de I. cristalina usada el día anterior; el potasio por vía oral se prolongará durante 5 a 7 días...