Comparison among the euglycemic-hyperinsulinemic clamp, insulin-modified frequently sampled intravenous glucose tolerance test, and oral glucose tolerance test for assessment of insulin sensitivity in healthy Standardbreds.

Objective: To compare, in horses, estimates of insulin sensitivity obtained from minimal model analysis (MMA) of a frequently sampled IV glucose tolerance test (FSIGTT) with estimates from the euglycemic-hyperinsulinemic clamp (EHC) and to evaluate the validity of surrogate estimates of insulin sensitivity derived from an oral glucose tolerance test (OGTT).

Animals: 18 mature Standardbreds (mean ± SD body weight, 428.9 ± 35.

Cell death atlas of the postnatal mouse ventral forebrain and hypothalamus: effects of age and sex.

Naturally occurring cell death is essential to the development of the mammalian nervous system. Although the importance of developmental cell death has been appreciated for decades, there is no comprehensive account of cell death across brain areas in the mouse. Moreover, several regional sex differences in cell death have been described for the ventral forebrain and hypothalamus, but it is not known how widespread the phenomenon is.

Standing low-field magnetic resonance imaging appearance of normal collateral ligaments of the equine distal interphalangeal joint.

High- and low-field magnetic resonance (MR) imaging systems are available for clinical diagnosis of collateral desmopathy of the equine distal interphalangeal joint (DIJ). Knowledge of the normal appearance, size, shape,and signal variation of these ligaments on high- and low-field MR images is essential when assessing desmopathy detected by MR imaging. However, there are no descriptions of the normal features of DIJ collateral ligaments on images obtained with a standing low-field MR system.

Effects of acute hyperinsulinemia on inflammatory proteins in horses.

Laminitis is a painful, inflammatory disease of the equine hoof that often results in euthanasia. Elevated plasma insulin concentrations are a predictive factor for laminitis, and in previously healthy horses and ponies, laminitis was induced by infusion of insulin. Thus, we chose to determine if an infusion of insulin would increase plasma concentrations of inflammatory cytokines and cytokine mRNA abundance in subcutaneous adipose tissue, skeletal muscle, and white blood cells.

Glucose and insulin dynamics associated with continuous rate infusion of dextrose solution or dextrose solution and insulin in healthy and endotoxin-exposed horses.

Objective: To investigate the effects of a continuous rate infusion (CRI) of dextrose solution or dextrose solution and insulin on glucose and insulin concentrations in healthy and endotoxin-exposed horses.

Animals: 9 adult mares.

Procedures: During phase 1, treatments consisted of saline (0.

Effect of feeding a high-protein diet following an 18-hour period of feed withholding on mammalian target of rapamycin-dependent signaling in skeletal muscle of mature horses.

Objective: To determine the effect of refeeding following an 18-hour period of feed withholding on the phosphorylation of translation initiation factors in the skeletal muscle of mature horses.

Animals: 8 adult horses.

Procedures: Following an 18-hour period of feed withholding, horses either continued to have feed withheld (postabsorptive state) or were fed 2 g/kg of a high-protein feed (33% crude protein) at time 0 and 30 minutes (postprandial state).

Effects of exercise training on adiposity, insulin sensitivity, and plasma hormone and lipid concentrations in overweight or obese, insulin-resistant horses.

Objective: To determine effects of exercise training without dietary restriction on adiposity, basal hormone and lipid concentrations and glucose and insulin dynamics in overweight or obese, insulin-resistant horses.

Animals: 12 overweight or obese (body condition score > or = 7), insulin-resistant (insulin sensitivity < or = 1.2 x 10(-4) L/min/mU) geldings.

Effects of diet-induced weight gain on insulin sensitivity and plasma hormone and lipid concentrations in horses.

Objective: To determine the effects of diet-induced weight gain on glucose and insulin dynamics and plasma hormone and lipid concentrations in horses.

Animals: 13 adult geldings.

Procedures: Horses were fed 200% of their digestible energy requirements for maintenance for 16 weeks to induce weight gain.

Effects of dexamethasone administration on insulin resistance and components of insulin signaling and glucose metabolism in equine skeletal muscle.

Objective: To determine the effects of dexamethasone treatment on selected components of insulin signaling and glucose metabolism in skeletal muscle obtained from horses before and after administration of a euglycemic-hyperinsulinemic clamp (EHC).

Animals: 6 adult Standardbreds.

Procedures: In a balanced crossover study, horses received either dexamethasone (0.

Effects of dexamethasone on glucose dynamics and insulin sensitivity in healthy horses.

Objective: To determine effects of dexamethasone on glucose dynamics and insulin sensitivity in healthy horses.

Animals: 6 adult Standardbreds.

Procedures: In a balanced crossover study, horses received dexamethasone (0.

Time course of insulin sensitivity and skeletal muscle glycogen synthase activity after a single bout of exercise in horses.

The time course of insulin sensitivity, skeletal muscle glycogen and GLUT4 content, and glycogen synthase (GS) activity after a single bout of intense exercise was examined in eight horses. On separate days, a euglycemic-hyperinsulinemic clamp (EHC) was undertaken at 0.5, 4, or 24 h after exercise or after 48 h of rest [control (Con)].

Deletion of the Bax gene disrupts sexual behavior and modestly impairs motor function in mice.

Cell death is a nearly ubiquitous feature of the developing nervous system, and differential death in males and females contributes to several well studied sex differences in neuron number. Nonetheless, the functional importance of neuronal cell death has been subjected to few direct tests. Bax, a pro-apoptotic protein, is required for cell death in many neural regions.

Repeatability of 2 methods for assessment of insulin sensitivity and glucose dynamics in horses.

Both the euglycemic-hyperinsulinemic clamp (EHC) and minimal model analysis of the frequently sampled intravenous glucose tolerance test (FSIGT) have been applied for measurement of insulin sensitivity in horses. However, no published data are available on the reproducibility of these methods. Therefore, the objective of this study was to evaluate the variation and repeatability of measures of glucose dynamics and insulin sensitivity in horses derived from minimal model analysis of the FSIGT and from the EHC method.

Effects of adenosine pretreatment on detection of free radicals in ischemic and reperfused canine gracilis muscle flaps by use of spin-trapping electron paramagnetic resonance spectroscopy.

Objective: To determine whether adenosine pretreatment attenuates free radical production and muscle damage in ischemic and reperfused canine skeletal muscle.

Animals: 9 healthy mixed-breed dogs.

Procedure: Dogs were anesthetized, and both gracilis muscles were isolated, leaving only the major vascular pedicle intact.