Genetics of canine diabetes mellitus: Are the diabetes susceptibility genes identified in humans involved in breed susceptibility to diabetes mellitus in dogs?

Diabetes mellitus is a common endocrinopathy in companion animals, characterised by hyperglycaemia, glycosuria and weight loss, resulting from an absolute or relative deficiency in the pancreatic hormone insulin. There are breed differences in susceptibility to diabetes mellitus in dogs, with the Samoyed breed being overrepresented, while Boxers are relatively absent in the UK population of diabetic dogs, suggesting that genetic factors play an important role in determining susceptibility to the disease. A number of genes, linked with susceptibility to diabetes mellitus in humans, are associated with an increased risk of diabetes mellitus in dogs, some of which appear to be relatively breed-specific. Diabetes mellitus in dogs has been associated with major histocompatibility complex (MHC) class II genes (dog leucocyte antigen; DLA), with similar haplotypes and genotypes being identified in the most susceptible breeds. A region containing a variable number of tandem repeats (VNTR) and several polymorphisms have been identified in the canine insulin gene, with some alleles associated with susceptibility or resistance to diabetes mellitus in a breed-specific manner. Polymorphisms in the canine CTLA4 promoter and in other immune response genes are associated with susceptibility to diabetes mellitus in a number of pedigree breeds. Genome wide association studies are currently underway that should shed further light on the genetic factors responsible for the breed profile seen in the diabetic dog population.     

Long‐term field study of transgenic hypovirulent strains of Cryphonectria parasitica in a forest setting

Transgenic hypovirulent strains of Cryphonectria parasitica, the chestnut blight fungus, engineered to contain a chromosomally integrated full‐length infectious cDNA copy of virulence‐attenuating hypoviruses, differ from natural hypovirulent strains in the ability to transmit hypoviruses to ascospore progeny and with 100% efficiency through asexual spores. We report the results of a long‐term field study that examined whether these properties result in enhanced hypovirulence establishment, dissemination and persistence under field conditions. Informed by previous field results using a severe hypovirus, this study that employed 144 American chestnut trees was designed to provide improved inoculum formulation and delivery and to include the use of a mild hypovirus isolate (less debilitating) CHV‐1/Euro7 in an attempt to increase dissemination. Isogenic transgenic hypovirulent (TG), non‐transgenic cytoplasmic hypovirulent (CH) or virus‐free virulent (V) treatment strains were applied to artificially initiated and natural C. parasitica cankers three times each year for 7 years. Reservoirs of treatment inoculum also were initiated and refreshed annually for the first 6 years of the study. Sampling of 111,000 individual ascospores from 4,500 perithecia confirmed hypovirus‐containing spermatia successfully transmitted TG hypoviruses to ascospore progeny under field conditions. Surprisingly, TG ascospore progeny were recovered 3 years after the last annual application of treatment inoculum. Repeated sampling of over 440 cankers revealed dissemination of both CH and TG hypovirulent strains. However, no significance differences in establishment or dissemination were observed for the two hypovirulent strains. The results are discussed in terms of the contribution of ascospore progeny to infection, competition by endemic virulent C. parasitica, size of inoculated trees and the biological control potential of TG hypovirulent strains.     

Transplacental Transfer of Iron in the Water Buffalo (Bubalus bubalis): Uteroferrin and Erythrophagocytosis

The objectives of this investigation were to understand transplacental transport of iron by secreted uteroferrin (UF) and haemophagous areas of water buffalo placenta and clarify the role(s) of blood extravasation at the placental‐maternal interface. Placentomes and interplacentomal region of 51 placentae at various stages of gestation were fixed, processed for light and transmission electron microscopy, histochemistry and immunohistochemistry. Haemophagous areas were present in placentomes collected between 4 and 10 months of pregnancy. Perl’s reaction for ferric iron was negative in placentomes, but positive in endometrial glands. Positive staining for UF indicated areas in which it was being taken up by phagocytosis and/or fluid phase pinocytosis in areolae of the interplacentomal mesenchyme, with little staining in endometrial stroma. Imunohistochemistry detected UF in trophectoderm of haemophagous regions of placentomes and in other parts of the foetal villous tree, but the strongest immunostaining was in the epithelial cells and lumen of uterine glands. Ultrastructural analyses indicated that erythrophagocytosis was occurring and that erythrocytes were present inside cells of the chorion that also contained endocytic vesicles and caveolae. Results of this study indicate that both the haemophagous areas of placentomes and the areolae at the interface between chorion and endometrial glands are important sites for iron transfer from mother to foetal‐placental tissues in buffalo throughout pregnancy.     

Seagrass on the edge: Land-use practices threaten coastal seagrass communities in Sabah, Malaysia

Seagrass meadows are susceptible to coastal environmental impacts and serve as early indicators of system-wide degradation. Two SeagrassNet monitoring sites were established in Sabah (Malaysia) in 2001 in the Tunku Abdul Rahman National Park: one a pristine, reference site and one anticipating impacts from nearby, ongoing waterfront development. At both sites, percent cover of all seagrass species declined significantly between 2003 and 2005. Water temperature, fine sediment and specific leaf biomass increased, while percent surface light intensity reaching the plants decreased. Evidence suggests that the temperature changes observed during the monitoring period were not sufficient to impact seagrasses; rather, the documented reduced subsurface light intensity caused the observed seagrass declines. Concomitantly, satellite imagery revealed a persistent sediment plume in these coastal waters associated with deforestation. SeagrassNet monitoring quickly documented seagrass losses and identified the causal environmental factor, providing timely information for management consideration.     

Shipboard geophysical indications of asymmetry and melt production beneath the east pacific rise near the MELT experiment

Near the Mantle Electromagnetic and Tomography (MELT) Experiment, seamounts form and off-axis lava flows occur in a zone that extends farther to the west of the East Pacific Rise than to the east, indicating a broad, asymmetric region of melt production. More seamounts, slower subsidence, and less dense mantle on the western flank suggest transport of hotter mantle toward the axis from the west. Variations in axial ridge shape, axial magma chamber continuity, off-axis volcanism, and apparent mantle density indicate that upwelling is probably faster and more melt is produced beneath 17 degrees15'S than beneath 15 degrees55'S. Recent volcanism occurs above mantle with the lowest seismic velocities.     

Therapeutic efficacy of zeta-cypermethrin pour-on for the treatment of biting and sucking lice in cattle under field conditions

OBJECTIVE: To assess the efficacy of zeta-cypermethrin pour-on to control cattle lice. DESIGN: Five field trials in south-eastern Australia. PROCEDURE: Zeta-cypermethrin pour-on, deltamethrin pour-on and pour-on vehicle were applied to groups of 10 cattle. Lice were counted before treatment and 14, 28, 42 and 56 days after treatment. RESULTS: Zeta-cypermethrin pour-on given at 2.5 mg/kg was equivalent to, or marginally more effective than a deltamethrin pour-on at 0.75 mg/kg. It eliminated B bovis and H eurysternus and gave good control of L vituli and S capillatus. Zeta-cypermethrin at 1 mg/kg gave good control of B bovis and H eurysternus but was not satisfactory against L vituli and S capillatus. CONCLUSION: Zeta-cypermethrin pour-on, given at 2.5 mg/kg, is an effective treatment for cattle lice control. Zeta-cypermethrin, and other synthetic pyrethroid pour-ons, are the treatment of choice to control B bovis.     

Disposition of fenbendazole in cattle

Fenbendazole (FBZ) was administered to cattle IV and orally in a crossover design. Plasma concentration vs time profiles were reported for FBZ and its major metabolites, the sulfoxide (oxfendazole) and the sulfone. The total excretion of FBZ and its metabolites in urine and feces was also measured for 6 days after administration. All known metabolites were identified in urine and feces except for fenbendazole amine. Neither this minor metabolite nor p-hydroxyfenbendazole (FBZ-OH) appeared in plasma. The major excretory product was FBZ-OH. After oral administration, only 44.6% of the dose was eliminated after 6 days, indicating a fairly high degree of sequestration, probably within the gastrointestinal tract.     

Application of GC-MS for the detection of lipophilic compounds in diverse plant tissues

Background  

The concept of metabolite profiling has been around for decades and technical innovations are now enabling it to be carried out on a large scale with respect to the number of both metabolites measured and experiments carried out. However, studies are generally confined to polar compounds alone. Here we describe a simple method for lipophilic compounds analysis in various plant tissues.     

Drug disposition in the neonatal animal, with particular reference to the foal

Differences between neonatal and adult animals in their response to drugs can usually be attributed to altered disposition (ie, distribution, metabolism and excretion) processes during the neonatal period. These alterations affect the plasma concentrations as well as the concentrations of drug attained at the receptor site. Some characteristics of the neonatal period include greater absorption from the gastrointestinal tract, lower extent of plasma protein binding, increased apparent volume of distribution of drugs that distribute in extracellular fluid or total body water, increased permeability of the 'blood-brain' barrier and slower elimination of many drugs. The hepatic microsomal oxidative reactions and glucuronide conjugation are deficient metabolic pathways for a varying period of time, usually up to six weeks after birth or even longer in some species. Decreased metabolism can affect the duration of action of lipid-soluble drugs. Functional immaturity of the kidneys decreases the renal excretion of polar drugs and drug metabolites. Overall renal function appears to reach maturity within two weeks after birth in ruminant species and pigs, while maturation may take at least four weeks in other species of domestic animals. Considerable physiological and biochemical development takes place during the first five days after birth with maturation continuing more slowly over the succeeding five weeks. The time it takes for any process to reach functional maturity depends on the process in question and varies with the species of animal. The absorption, disposition and pharmacological response to drugs during the first 24 h after birth may be unique to that time and, because of lack of information, are impossible to predict.(ABSTRACT TRUNCATED AT 250 WORDS)