The photolysis of quinomethionate in benzene solution

The photolysis of quinomethionate in benzene solution was found to result in complete cleavage of the dithiole ring with loss of both sulphur atoms. Products isolated and identified were those arising from the reaction of intermediate radicals with oxygen and with the solvent. They were identified, by gas chromatography-mass spectrometry and by comparison with authentic samples synthesised by known methods, as 6-methyl-1,2,3,4-tetrahydroquinoxaline-2,3-dione and 6- and 7-methyl-3-phenyl-1,2- dihydroquinoxalin-2-one. A mechanism that accounts for the formation of these products is presented.     

Spatial and temporal patterns of pig herds diagnosed with Postweaning Multisystemic Wasting Syndrome (PMWS) during the first two years of its occurrence in Denmark

The clinical syndrome Postweaning Multisystemic Wasting Syndrome (PMWS) in pigs has emerged globally during the last decade. In October 2001, the first pig herd diagnosed with PMWS was reported in Denmark, and since then the number of herds diagnosed with PMWS has increased markedly. The etiology of PMWS is not well understood, but increased knowledge of the causal factors is prerequisite for applying preventive interventions. In this study we described the temporal (time of diagnosis), spatial (location of herds) and spatio-temporal pattern of Danish pig herds diagnosed with PMWS during the first two years after the first herd was diagnosed, and we tested for spatial and spatio-temporal clustering using scan statistics. The study population consisted of pig herds that during the study period (October 2001-September 2003) performed diagnostic submissions to the two major veterinary diagnostic laboratories in Denmark (6724 herds). Of these, 277 herds were diagnosed with PMWS. Two statistically significant spatial clusters of herds diagnosed with PMWS were identified. These clusters included 11% and 8% of the study herds, respectively. Within these two clusters the relative risk for a herd to be diagnosed with PMWS was twice as high as expected. One statistically significant spatio-temporal cluster was identified between February and May 2002. We discuss different hypotheses that could explain why pig herds diagnosed with PMWS were clustered both spatially and spatio-temporally, and conclude that the results support the hypothesis that PMWS is caused by introduction of a new, unidentified, pathogen into the Danish pig production.     

Quantitative analysis of inflammatory and immune responses in dogs with gastritis and their relationship to Helicobacter spp. infection

The present study sought to quantitatively examine mucosal inflammatory and immune responses in dogs with gastritis and the relationship of these responses to infection with Helicobacter. Gastric biopsies from 30 dogs were evaluated for B- and T-lymphocytes, neutrophils, eosinophils, macrophages, and mast cells. Mucosal atrophy, fibrosis, cellularity, and severity of gastritis were graded qualitatively. Messenger-RNA (mRNA) for actin, interleukin-1beta (IL-1beta), IL-4, IL-8, and IL-10, transforming growth factor beta (TGF-beta), and interferon gamma (IFN-gamma) was quantified by polymerase chain reaction (PCR). The presence of Helicobacter spp. was determined by urease activity, histology, PCR, and enzyme-linked immunosorbent assay. mRNA for IL-1beta, IL-8, IL-10, TGF-beta, and IFN-gamma was detected in most dogs. IL-4 mRNA was detected in only 1 dog. Correlations were observed for IL-1beta versus IL-8 and IL-10; IL-8 versus IL-10, IFN-gamma, and TGF-beta; and IL-10 versus IFN-y. Mucosal pathology was related to cytokine mRNA expression (neutrophils to IL-8 and IFN-gamma, macrophages and lymphocytes to IFN-gamma, and fibrosis to IL-1beta). Gastritis was categorized as lymphoplasmacytic in all dogs, and its histologic severity correlated with atrophy, infiltration with lymphocytes and macrophages, and expression of IL-10 and IFN-gamma. Of the dogs examined, 76.7% were infected with Helicobacter spp. Infection was associated with increased expression of TGF-beta and fibrosis. Circulating anti-Helicobacter immunoglobulin G titers were higher in uninfected than infected dogs. We conclude that lymphoplasmacytic gastritis in dogs is characterized by concurrent activation of proinflammatory and immunomodulatory cytokines, with increased mRNA expression related to mucosal pathology. No significant associations between Helicobacter infection and proinflammatory cytokine expression, severity of gastritis, or differences in the pathogenicity of different Helicobacter spp. were found.     

A retrospective analysis of case series using home-prepared and chicken hydrolysate diets in the diagnosis of adverse food reactions in 181 pruritic dogs

The purpose of this retrospective study was to compare home-prepared and chicken hydrolysate diets in the diagnosis of canine adverse food reactions (AFR). Seventy-two dogs were fed home-prepared diets and 109 were fed hydrolysate. Owners chose the type of diet at presentation, and ingredients of home-prepared diets were selected depending on each dog's dietary history. Ectoparasitic infestations and microbial infections were treated during the trials. Cutaneous and gastrointestinal signs and pruritus scores were recorded before starting the diet, 6 weeks into the trials and after provocation with the original diets. AFR was diagnosed if pruritus resolved during the trial and recurred on dietary provocation. The dropout rate was lower for home-prepared diets although not statistically significant (18.1% home prepared; 24.7% hydrolysate, P=0.377). AFR alone was diagnosed in 10 dogs (17%) using home-prepared diets and in 15 (18.3%) fed the hydrolysate. Gastrointestinal problems were more frequent in dogs with AFR than in dogs without AFR (P=0.001). Another 11 dogs (18.6%) in the home-prepared diet group and 20 (24.4%) in the hydrolysate diet group had AFR concurrent with other pruritic diseases, mainly atopy. The similar frequencies of AFR diagnosis in the two groups (P=0.837 AFR; P=0.416 concurrent AFR) indicate that the chicken hydrolysate diet may be a valuable alternative to home-prepared diets in the diagnosis of canine AFR. Prospective cross-over studies are warranted to confirm these findings.     

Cooking effects on water distribution in potatoes using nuclear magnetic resonance relaxation

Continuous low-field (LF) (1)H NMR relaxometry was used to monitor the structural changes during cooking of potatoes with two different dry matter (DM) contents. A principal component analysis of the relaxation decay curves revealed major events related to water mobility during cooking, which occur at 53 and 60 degrees C for potatoes with medium and low DM contents, respectively. Exponential analysis of the relaxation decays reveals two major water populations in the potato: a slow-relaxing (assigned to water in cytoplasm and extracellular cavities) water component, T(22) ( approximately 350-550 ms), and a fast-relaxing component (primarily assigned to water associated with starch and cell walls), T(21) ( approximately 45-65 ms). Significant DM dependent shifts in both the T(21) and T(22) relaxation time constants were observed during cooking, indicating that starch gelatinizes between 53 and 70 degrees C with water exchanging with the hydroxyls of starch (transition in T(21)) and cells start to disrupt with an increase in diffusion volumes at approximately 60 degrees C (transition in T(22)). The study reveals that continuous LF NMR measurement is an excellent and highly sensitive method to study changes in water mobility and water populations during the cooking of potatoes.