Ultrasonographic measurement of normal renal parameters

Both kidneys were imaged ultrasono-graphically in each of 100 normal adult dogs. Small but significant differences were found in the dimensions of the left and right kidneys and in renal dimensions of male and female dogs of similar bodyweight. There was a statistically significant correlation between renal length and bodyweight (r = 0–84, P<0–001). The relationship between renal length and bodyweight was linear except at very low or very high bodyweights. There was also a statistically significant correlation between renal volume and bodyweight (r = 0–91, P<0–001), and the relationship remained linear even at extremes of bodyweight. Graphs could therefore be constructed for renal lengthy bodyweight and renal volume/bodyweight with 95 per cent confidence limits.     

Subcellular distribution of copper in the liver of fetal deer in the last month of gestation

Fetal deer, in the last month of gestation, accumulate high concentrations of copper in the liver. Livers from fetal deer in late gestation were homogenised and fractionated by continuous sucrose density gradient centrifugation. The distribution of copper closely followed that of DNA; approximately two thirds of the metal was localised to the nuclear fractions with the remaining third in the cytosolic fractions. The fractionation procedure was repeated with digitonin, a lysosomal perturbant: lysosomes were disrupted and the marker enzyme, N-acetyl-beta-glucosaminidase, shifted from the particulate fractions to the cytosolic fractions; the distribution of copper was unaffected. Differential centrifugation of homogenate confirmed that approximately two thirds of the copper was associated with the nuclear fraction. Further confirmation of a nuclear localisation of copper was provided by X-ray microanalysis of purified nuclei.     

Recovery characteristics following maintenance of anaesthesia with sevoflurane or isoflurane in dogs premedicated with acepromazine

A standard anaesthetic protocol was used to anaesthetise 40 dogs for intravenous urography and a retrograde urethrogram or vaginourethrogram. The dogs were allocated by blocked randomisation to receive either isoflurane or sevoflurane for maintenance of anaesthesia after they had been premedicated with acepromazine and pethidine, and anaesthesia induced with propofol. An observer who was unaware of which agent had been used assessed ataxia 30 and 60 minutes after discontinuation of administration of the anaesthetic and assigned an overall recovery score. No complications occurred during anaesthesia of either group of dogs. The scores for ataxia were significantly lower after 60 minutes than after 30 minutes, but there was no significant difference between the groups. The quality of recovery was significantly better in the dogs that received sevoflurane than in those that received isoflurane, but the recovery times were similar.     

Regulation of protein secretion through controlled aggregation in the endoplasmic reticulum

A system for direct pharmacologic control of protein secretion was developed to allow rapid and pulsatile delivery of therapeutic proteins. A protein was engineered so that it accumulated as aggregates in the endoplasmic reticulum. Secretion was then stimulated by a synthetic small-molecule drug that induces protein disaggregation. Rapid and transient secretion of growth hormone and insulin was achieved in vitro and in vivo. A regulated pulse of insulin secretion resulted in a transient correction of serum glucose concentrations in a mouse model of hyperglycemia. This approach may make gene therapy a viable method for delivery of polypeptides that require rapid and regulated delivery.     

Human-specific gain of function in a developmental enhancer

Changes in gene regulation are thought to have contributed to the evolution of human development. However, in vivo evidence for uniquely human developmental regulatory function has remained elusive. In transgenic mice, a conserved noncoding sequence (HACNS1) that evolved extremely rapidly in humans acted as an enhancer of gene expression that has gained a strong limb expression domain relative to the orthologous elements from chimpanzee and rhesus macaque. This gain of function was consistent across two developmental stages in the mouse and included the presumptive anterior wrist and proximal thumb. In vivo analyses with synthetic enhancers, in which human-specific substitutions were introduced into the chimpanzee enhancer sequence or reverted in the human enhancer to the ancestral state, indicated that 13 substitutions clustered in an 81-base pair module otherwise highly constrained among terrestrial vertebrates were sufficient to confer the human-specific limb expression domain.