Single nucleotide polymorphisms in the growth hormone and insulin-like growth factor-1 genes are associated with milk production, body condition score and fertility traits in dairy cows.

The somatotrophic axis (GH-IGF) is a key regulator of animal growth and development, affecting performance traits that include milk production, growth rate, body composition, and fertility. The aim of this study was to quantify the association of previously identified SNPs in bovine growth hormone (GH1) and insulin-like growth factor 1 (IGF-1) genes with direct performance trait measurements of lactation and fertility in Holstein-Friesian lactating dairy cows. Sixteen SNPs in both IGF-1 and GH1 were genotyped across 610 cows and association analyses were carried out with traits of economic importance including calving interval, pregnancy rate to first service and 305-day milk production, using animal linear mixed models accounting for additive genetic effects. Two IGF-1 SNPs, IGF1i1 and IGF1i2, were significantly associated with body condition score at calving, while a single IGF-1 SNP, IGF1i3, was significantly associated with milk production, including milk yield (means ± SEM; 751.3 ± 262.0 kg), fat yield (21.3 ± 10.2 kg) and protein yield (16.5 ± 8.0 kg) per lactation. Only one GH1 SNP, GH33, was significantly associated with milk protein yield in the second lactation (allele substitution effect of 9.8 ± 5.0 kg). Several GH1 SNPs were significantly associated with fertility, including GH32, GH35 and GH38 with calving to third parity (22.4 ± 11.3 days) (GH32 and GH38 only), pregnancy rate to first service (0.1%) and overall pregnancy rate (0.05%). The results of this study demonstrate the effects of variants of the somatotrophic axis on milk production and fertility traits in commercial dairy cattle.

Viral measurement by polymerase chain reaction-based assays in human immunodeficiency virus-infected infants.

Serial samples from human immunodeficiency virus-infected infants in the first year of life were analyzed by quantitative human immunodeficiency virus polymerase chain reaction assays. Very high, persistent levels of plasma RNA and proviral DNA were detected throughout the study period, suggesting the absence of an effective immune response. Most patients had normal CD4 lymphocyte counts and were symptom free for the first 3 to 6 months despite high levels of viral replication. These findings support the evaluation of early intervention (before symptoms develop) and efforts to establish the predictive value of these assays.

Low-dose insulin infusion in the treatment of diabetic ketoacidosis: bolus versus no bolus.

The effects of an initial iv bolus of insulin upon plasma glucose, blood gases, and electrolytes were assessed in 19 children with 20 episodes of diabetic ketoacidosis treated by a continuous low-dose insulin infusion of 0.1 unit/kg/hour. An iv bolus of insulin administered prior to low-dose insulin infusion accelerated the decline of plasma glucose concentration during the first hour of treatment, but differences in decline of mean plasma glucose concentration were not apparent thereafter. The mean time required for attaining "normoglycemia" (250 mg/dl) was similar, whether or not the initial bolus of insulin was given, with a smooth and predictable correction of initial hyperglycemia in the majority of children. However, an accelerated response was more frequent in those patients with compensated metabolic acidosis, who received an initial iv bolus of insulin; those with more severe metabolic acidosis took longer to recover. The data suggest that an initial iv bolus of insulin may not be required nor desirable in the majority of children with diabetic ketoacidosis treated by a standard low-dose insulin infusion regimen.