Impact features on Stardust: implications for comet 81P/Wild 2 dust

Particles emanating from comet 81P/Wild 2 collided with the Stardust spacecraft at 6.1 kilometers per second, producing hypervelocity impact features on the collector surfaces that were returned to Earth. The morphologies of these surprisingly diverse features were created by particles varying from dense mineral grains to loosely bound, polymineralic aggregates ranging from tens of nanometers to hundreds of micrometers in size. The cumulative size distribution of Wild 2 dust is shallower than that of comet Halley, yet steeper than that of comet Grigg-Skjellerup.     

Epidemiologic evaluation of multiple respiratory pathogens in cats in animal shelters

Upper respiratory tract infection (URI) propagates readily within cats in shelters and often results in euthanasia of affected cats. In a case-control evaluation of 573 cats in eight shelters in California in 2001 and 2002, the prevalence of feline calicivirus (FCV) was from 13 to 36%, feline herpesvirus (FHV) was from 3 to 38%, and prevalence of Bordetella bronchiseptica, Chlamydophila felis, and Mycoplasma species was from 2 to 14%. Cats with URI tended to be housed in isolation, dehydrated, and younger than cats without URI, and infected with FHV, Mycoplasma species, FCV, or C felis. Shelters differed in the prevalence of pathogens and many cats appeared positive for infection after about 1 week of sheltering. It is helpful for shelters to understand the risk factors associated with URI in order to evaluate the costs and benefits of treatment and improve their procedures to decrease the incidence of URI within their facilities. Antiherpetics and antimycoplasmal drugs may be beneficial for individual animal care. Results document the utility of comprehensive URI surveillance and herd management for specific pathogens typical in that shelter.     

Effect of Flavonoids and Saponins Extracted from Black Bean (Phaseolus vulgaris L.) Seed Coats as Cholesterol Micelle Disruptors

Strategies for reducing plasma cholesterol have been focused on reducing the absorption or synthesis of cholesterol. The aim of this study was to correlate the content of flavonoids and saponins in black bean (Phaseolus vulgaris L.) seed coats extracts with a potential effect in lowering cholesterol absorption by the inhibition of cholesterol micellar solubility. Extracts with different flavonoids and saponins concentration were obtained from a Box-Behnken design used to optimize extraction temperature, stirring time and solvent composition. Major flavonoids and saponins were quantified by HPLC-PDA-ELSD and confirmed through mass spectrometry. Contrary to the flavonoid content, saponins were correlated to the inhibitory effect of cholesterol micelle solubility as an approach to a potential reduction of cholesterol absorption. Extracts with the highest saponin content strongly inhibited cholesterol micellization with values of 55.4?±?1.9 %, while stigmasterol used as control, only reached 12?±?2.3 % at the same concentration (5 mg/ml). The optimal extracting conditions for saponins were 25 °C, during 3 h in 85 % aqueous-methanol. Correlations of inhibitory effect of cholesterol micellar solubility with the content of each identified saponin suggested that the reduction of cholesterol micellization depends on the C-22 substitution of saponins.     

Dietary Antioxidants, Cognitive Function and Dementia - A Systematic Review

Antioxidant compounds, contained in fruit, vegetables and tea, have been postulated to have a protective effect against age-related cognitive decline by combating oxidative stress. However, recent research on this subject has been conflicting. The aim of this systematic review was to consider current epidemiological and longitudinal evidence for an association between habitual dietary intake of antioxidants and cognition, with consideration given to both cognitive functioning and risk for dementia and its subtypes, including Alzheimer’s disease and vascular dementia. Searches of electronic databases were undertaken to identify peer-reviewed journal articles that reported on associations between antioxidant intakes (vitamins C, E, flavonoids, carotenoids) and cognitive function or risk for dementia. Eight cross-sectional and 13 longitudinal studies were identified and included in the review. There were mixed findings for the association between antioxidant intake, cognition and risk of dementia and Alzheimer’s disease. Large heterogeneity in study design, differential control of confounders, insufficient measures of cognitive performance, and difficulties associated with dietary assessment may contribute to the inconsistent findings. Overall, findings do not consistently show habitual intakes of dietary antioxidants are associated with better cognitive performance or a reduced risk for dementia. Future intervention trials are warranted to elucidate the effects of a high intake of dietary antioxidants on cognitive functioning, and to explore effects within a whole dietary pattern.     

Histological and morphometric lesions in the pre-clinical,developmental phase of insulin-induced laminitis in Standardbred horses

Lamellar pathology in experimentally-induced equine laminitis associated with euglycaemic hyperinsulinaemia is substantial by the acute, clinical phase (～48 h post-induction). However, lamellar pathology of the developmental, pre-clinical phase requires evaluation. The aim of this study was to analyse lamellar lesions both qualitatively and quantitatively, 6, 12 and 24 h after the commencement of hyperinsulinaemia. Histological and histomorphometrical analyses of lamellar pathology at each time-point included assessment of lamellar length and width, epidermal cell proliferation and death, basement membrane (BM) pathology and leucocyte infiltration. Archived lamellar tissue from control horses and those with acute, insulin-induced laminitis (48 h) was also assessed for cellular proliferative activity by counting the number of cells showing positive nuclear immuno labelling for TPX2.Decreased secondary epidermal lamellar (SEL) width and increased histomorphological evidence of SEL epidermal basal (and supra-basal) cell death occurred early in disease progression (6 h). Increased cellular proliferation in SELs, infiltration of the dermis with small numbers of leucocytes and BM damage occurred later (24 and 48 h). Some lesions, such as narrowing of the SELs, were progressive over this time period (6–48 h). Cellular pathology preceded leucocyte infiltration and BM pathology, indicating that the latter changes may be secondary or downstream events in hyperinsulinaemic laminitis.     

An assessment of external biosecurity on southern Ontario swine farms and its application to surveillance on a geographic level

Risk-based surveillance is becoming increasingly important in the veterinary and public health fields. It serves as a means of increasing surveillance sensitivity and improving cost-effectiveness in an increasingly resource-limited environment. Our approach for developing a tool for the risk-based geographical surveillance of contagious diseases of swine incorporates information about animal density and external biosecurity practices within swine herds in southern Ontario. The objectives of this study were to group the sample of herds into discrete biosecurity groups, to develop a map of southern Ontario that can be used as a tool in the risk-based geographical surveillance of contagious swine diseases, and to identify significant predictors of biosecurity group membership. A subset of external biosecurity variables was selected for 2-step cluster analysis and latent class analysis (LCA). It was determined that 4 was the best number of groups to describe the data, using both analytical approaches. The authors named these groups: i) high biosecurity herds that were open with respect to replacement animals; ii) high biosecurity herds that were closed with respect to replacement animals; iii) moderate biosecurity herds; and iv) low biosecurity herds. The risk map was developed using information about the geographic distribution of herds in the biosecurity groups, as well as the density of swine sites and of grower-finisher pigs in the study region. Finally, multinomial logistic regression identified heat production units (HPUs), number of incoming pig shipments per month, and herd type as significant predictors of biosecurity group membership. It was concluded that the ability to identify areas of high and low risk for disease may improve the success of surveillance and eradication projects.     

The prevalence of Mycoplasma ovipneumoniae and Mycoplasma arginini in the respiratory tract of sheep

Abstract

Extract

In an initial study of mycoplasmas of the respiratory tract of New Zealand sheep a number of strains of mycoplasma were recovered and identified as either M. ovipneumoniae or M. arginini (Clarke et al., 1974 Clarke, J. K., Brown, V. G. and Alley, M. R. 1974. Isolation and identification of mycoplasmas from the respiratory tract of sheep in New Zealand. N.Z. vet. J., 22: 117–121. [Taylor &; Francis Online] , [Google Scholar]). Investigations in Australia have produced evidence that M. ovipneumoniae is associated with a proliferative interstitial pneumonia in Queensland sheep (Sullivan et al., 1973 Sullivan, N. D., St. George, T. D. and Horsfall, N. 1973. A proliferative interstitial pneumonia of sheep associated with mycoplasma infection. I. Natural history of the disease in a flock. Aust. vet. J., 49: 57–62.  [Google Scholar]) and for this reason the present survey was undertaken to investigate the prevalence of mycoplasmas in the respiratory tract of sheepin New Zealand.     

Interleukin‐31: its role in canine pruritus and naturally occurring canine atopic dermatitis

Background – Interleukin‐31 (IL‐31) is a member of the gp130/interleukin‐6 cytokine family that is produced by cell types such as T helper 2 lymphocytes and cutaneous lymphocyte antigen positive skin homing T cells. When overexpressed in transgenic mice, IL‐31 induces severe pruritus, alopecia and skin lesions. In humans, IL‐31 serum levels correlate with the severity of atopic dermatitis in adults and children. Hypothesis/Objective – To determine the role of IL‐31 in canine pruritus and naturally occurring canine atopic dermatitis (AD). Animals – Purpose‐bred beagle dogs were used for laboratory studies. Serum samples were obtained from laboratory animals, nondiseased client‐owned dogs and client‐owned dogs diagnosed with naturally occurring AD. Methods – Purpose‐bred beagle dogs were administered canine interleukin‐31 (cIL‐31) via several routes (intravenous, subcutaneous or intradermal), and pruritic behaviour was observed/quantified via video monitoring. Quantitative immunoassay techniques were employed to measure serum levels of cIL‐31 in dogs. Results – Injection of cIL‐31 into laboratory beagle dogs caused transient episodes of pruritic behaviour regardless of the route of administration. When evaluated over a 2 h period, dogs receiving cIL‐31 exhibited a significant increase in pruritic behaviour compared with dogs that received placebo. In addition, cIL‐31 levels were detectable in 57% of dogs with naturally occurring AD (≥13 pg/mL) but were below limits of quantification (<13 pg/mL) in normal, nondiseased laboratory or client‐owned animals. Conclusions – Canine IL‐31 induced pruritic behaviours in dogs. Canine IL‐31 was detected in the majority of dogs with naturally occurring AD, suggesting that this cytokine may play an important role in pruritic allergic skin conditions, such as atopic dermatitis, in this species.     

Experimental snowpack reduction alters organic matter and net N mineralization potential of soil macroaggregates in a northern hardwood forest

Climate change is predicted to reduce or delay annual wintertime snow pack formation in the forests of the northeastern US. Any delay in snowpack formation could increase soil freezing in winter and, thereby, alter soil characteristics and processes. We examined the hypothesis that delayed snowpack would disrupt soil structure and change organic matter bioavailability in an experimental snow removal study at the Hubbard Brook Experimental Forest (HBEF), NH, USA. Pairs of reference and snow removal treatment plots were studied in four different sites at HBEF. Snow was removed from November–January of two winters, inducing soil freezing throughout both winters. Size class distribution and organic matter concentration and content of aggregates, and carbon and nitrogen mineralization potential of size fractions were quantified for surface mineral soils in the spring of both years immediately after snowmelt. In the first year of sampling, the only significant effect of snow removal was an increase in the smallest (<53 μm) size fraction of mineral soil. In the second year, snow removal increased organic matter concentrations of macroaggregate (250–2,000 μm) and microaggregate (53–250 μm) size fractions. This change corresponded to an increase in net N mineralization potential and the ratio of N to C mineralized in the macroaggregate fraction, but there were no effects of snow removal on C mineralization. We propose that soil freezing increases the movement of organic matter from organic to mineral soil horizons and increases the N content of mineralizable substrates in mineral soil following years with delayed snowpack formation.     

Survival and Growth of Isolated Polyps of Galaxea fascicularis (Linnaeus 1767) on Six Kinds of Culture Substrates: Implications for Mariculture,Aquarium Culture,and Conservation

Coral aquaculture is viewed as a sustainable method of providing colonies for use in the aquarium trade, pharmacological studies, and coral reef rehabilitation. The production of large, healthy specimens depends on providing conditions that mimic or surpass natural reef environments. Materials with a high degree of variability in physical and chemical properties are utilized as substrates in coral aquaculture, but until fragment–substrate interactions are isolated and independently studied, the possible inhibitory and facilitative effects of each material will remain unclear. To understand potential key roles that substrates can play in coral culture, a comparison was made about the role of various materials on fragment survival and growth. The experiment examined the interactions between isolates of a common scleractinian coral, Galaxea fascicularis, and six commonly used substrates (coral rock, terracotta, polyvinyl chloride, steel, rubber tire, and concrete) and how these affected survival and growth. No differences were observed in the survival, colony size, and polyp production of the resulting microcolonies. The results show that, for G. fascicularis, growth is not affected by substrate type. The results demonstrate the use of a wide variety of materials for the successful aquaculture of scleractinian corals.