Comparative genome and proteome analysis of Anopheles gambiae and Drosophila melanogaster

Comparison of the genomes and proteomes of the two diptera Anopheles gambiae and Drosophila melanogaster, which diverged about 250 million years ago, reveals considerable similarities. However, numerous differences are also observed; some of these must reflect the selection and subsequent adaptation associated with different ecologies and life strategies. Almost half of the genes in both genomes are interpreted as orthologs and show an average sequence identity of about 56%, which is slightly lower than that observed between the orthologs of the pufferfish and human (diverged about 450 million years ago). This indicates that these two insects diverged considerably faster than vertebrates. Aligned sequences reveal that orthologous genes have retained only half of their intron/exon structure, indicating that intron gains or losses have occurred at a rate of about one per gene per 125 million years. Chromosomal arms exhibit significant remnants of homology between the two species, although only 34% of the genes colocalize in small "microsyntenic" clusters, and major interarm transfers as well as intra-arm shuffling of gene order are detected.     

The effect of epidural morphine on the minimum alveolar concentration of isoflurane in cats

This study was undertaken to evaluate the effect of 3 different doses of epidurally administered morphine sulphate on the minimum alveolar concentration (MAC) of isoflurane in healthy cats. Five 4-year-old, spayed female cats weighing 4.7 ± 0.8 kg were allocated randomly to receive one of 3 doses of morphine on each study day. The 3 doses of morphine were 0.05, 0.1 and 0.2 mg/kg bwt and each cat was studied 3 times so that each cat received all doses. On each study day, cats were anaesthetised with isoflurane and instrumented. The MAC of isoflurane was determined in triplicate and morphine sulphate was administered via an epidural catheter chronically implanted prior to the study. Maximum MAC reduction was determined over the following 2 h. At the end of the study cats were allowed to recover. There was a significant reduction in MAC of isoflurane, with all doses of epidural morphine (P<0.05). The maximum reduction in MAC of isoflurane after 0.05 mg/kg bwt, 0.10 mg/kg bwt and 0.20 mg/kg bwt morphine was 21.4 ± 9.796, 30.8 ± 9.696, and 30.2 ± 6.8%, respectively, with no significant difference between doses. Systolic, mean and diastolic blood pressure, heart rate, respiratory rate and arterial pH decreased significantly whereas arterial carbon dioxide tension increased significantly after morphine administration (P<0.05). The means for all variables returned to pre-morphine values when the end-tidal isoflurane concentration was reduced to the new MAC point. In conclusion, epidural morphine decreased the concentration of isoflurane required to prevent movement in response to noxious mechanical stimulation to the tail base. A similar effect may be seen clinically allowing lower doses of isoflurane to be used to provide surgical anaesthesia for procedures involving the hind limbs, pelvis and tail.     

Vancomycin for multi-drug resistant Enterococcus faecium cholangiohepatitis in a cat

A 12-year-old, neutered male domestic shorthair cat was evaluated with a life-long history of intermittent, predominantly small bowel diarrhea and a 3 day history of hematochezia. At presentation, the cat had increased liver enzyme activities and an inflammatory leukogram. Histopathology demonstrated inflammatory bowel disease (IBD), cholangiohepatitis and pancreatitis. The cholangiohepatitis was associated with a multi-drug resistant Enterococcus faecium. Gallbladder agenesis was also documented. Treatment with vancomycin was safely instituted for 10 days. Clinical signs resolved, however, cure of the bacterial cholangiohepatitis was not achieved. The risk of vancomycin resistant enterococci (VRE) in human and veterinary medicine is discussed.     

High intensity exercise conditioning increases accumulated oxygen deficit of horses

High intensity exercise is associated with production of energy by both aerobic and anaerobic metabolism. Conditioning by repeated exercise increases the maximal rate of aerobic metabolism, aerobic capacity, of horses, but whether the maximal amount of energy provided by anaerobic metabolism, anaerobic capacity, can be increased by conditioning of horses is unknown. We, therefore, examined the effects of 10 weeks of regular (4-5 days/week) high intensity (92+/-3 % VO2max) exercise on accumulated oxygen deficit of 8 Standardbred horses that had been confined to box stalls for 12 weeks. Exercise conditioning resulted in increases of 17% in VO2max (P<0.001), 11% in the speed at which VO2max was achieved (P = 0.019) and 9% in the speed at 115% of VO2max (P = 0.003). During a high speed exercise test at 115% VO2max, sprint duration was 25% longer (P = 0.047), oxygen demand was 36% greater (P<0.001), oxygen consumption was 38% greater (P<0.001) and accumulated oxygen deficit was 27% higher (P = 0.040) than values before conditioning. VLa4 was 33% higher (P<0.05) after conditioning. There was no effect of conditioning on blood lactate concentration at the speed producing VO2max or at the end of the high speed exercise test. The rate of increase in muscle lactate concentration was greater (P = 0.006) in horses before conditioning. Muscle glycogen concentrations before exercise were 17% higher (P<0.05) after conditioning. Exercise resulted in nearly identical (P = 0.938) reductions in muscle glycogen concentrations before and after conditioning. There was no detectable effect of conditioning on muscle buffering capacity. These results are consistent with a conditioning-induced increase in both aerobic and anaerobic capacity of horses demonstrating that anaerobic capacity of horses can be increased by an appropriate conditioning programme that includes regular, high intensity exercise. Furthermore, increases in anaerobic capacity are not reflected in blood lactate concentrations measured during intense, exhaustive exercise or during recovery from such exercise.