Seroprevalence of Encephalitozoon cuniculi and Toxoplasma gondii antibodies and risk-factor assessment for Encephalitozoon cuniculi seroprevalence in Finnish pet rabbits (Oryctolagus cuniculus).

BACKGROUND: Neurological signs, such as head tilt, torticollis, paralysis, and seizures, are common in rabbits. Differential diagnoses include two zoonotic infections caused by the microsporidial fungi Encephalitozoon cuniculi and the apicomplexan protozoa Toxoplasma gondii. Both infections are mainly latent in rabbits but may cause severe or even fatal disease. Although several international studies have reported the seroprevalence of these pathogens in different commercial rabbit populations, similar prevalence studies and risk-factor analyses among family-owned pet rabbits are uncommon and lacking in Scandinavia. We sought to estimate the seroprevalence and possible risk factors for E. cuniculi and T. gondii among Finnish pet rabbits. We used ELISA to measure E. cuniculi IgG seroprevalence of 247 rabbits and modified direct agglutination test for T. gondii seroprevalence of 270 rabbits. Samples were collected as part of the Finnish Pet Rabbit Health Research project. Internet-based questionnaires (n = 231) completed by the rabbit owners were used for risk-factor analysis. RESULTS: The apparent seroprevalence of E. cuniculi was 29.2% and true seroprevalence of T. gondii 3.9%. Risk factors were analysed only for E. cuniculi due to the low T. gondii seroprevalence. The final multivariable logistic regression model revealed that rabbits spending the whole summer outdoors had a higher risk of being E. cuniculi seropositive than rabbits with limited outdoor access. Additionally, rabbits living in households with only one or two rabbits had higher risk of being E. cuniculi seropositive than those in multi-rabbit households. CONCLUSIONS: Nearly one third of Finnish pet rabbits participating in this study had E. cuniculi IgG antibodies, indicating previous exposure to this pathogen. The prevalence is similar to that reported previously in clinically healthy rabbit populations in UK and Korea. While the seroprevalence of T. gondii was low (3.9%), antibodies were detected. Therefore, these zoonotic parasitic infections should be considered as differential diagnoses when treating rabbits.

Effects of a high-fat diet and global aryl hydrocarbon receptor deficiency on energy balance and liver retinoid status in male Sprague-Dawley rats.

The physiological functions of the aryl hydrocarbon receptor (AHR) are only beginning to unfold. Studies in wildtype and AHR knockout (AHRKO) mice have recently disclosed that AHR activity is required for obesity and steatohepatitis to develop when mice are fed with a high-fat diet (HFD). In addition, a line of AHRKO mouse has been reported to accumulate retinoids in the liver. Whether these are universal manifestations across species related to AHR activity level is not known yet. Therefore, we here subjected wildtype and AHRKO male rats (on Sprague-Dawley background) to HFD feeding coupled with free access to 10% sucrose solution and water; controls received a standard diet and water. Although the HFD-fed rats consumed more energy throughout the 24-week feeding regimen, they did not get overweight. However, relative weights of the brown and epididymal adipose tissues were elevated in HFD-fed rats, while that of the liver was lower in AHRKO than wildtype rats. Moreover, the four groups exhibited diet- or genotype-dependent differences in biochemical variables, some of which suggested marked dissimilarities from AHRKO mice. Expression of pro- and anti-inflammatory genes was induced in livers of HFD-fed AHRKO rats, but histologically they did not differ from others. HFD reduced the hepatic concentrations of retinyl palmitate, 9-cis-4-oxo-13,14-dihydroretinoic acid and (suggestively) retinol, whereas AHR status had no effect. Hence, the background strain/line of AHRKO rat is resistant to diet-induced obesity, and AHR does not modulate this or liver retinoid concentrations. Yet, subtle AHR-dependent differences in energy balance-related factors exist despite similar weight development.

The effect of a raw vs dry diet on serum biochemical, hematologic, blood iron, B12 , and folate levels in Staffordshire Bull Terriers.

BACKGROUND: To date, very few studies have compared the effects of different types of feeding practices on canine physiology, such as feeding exclusively dry, raw, or homemade foods. OBJECTIVES: We aimed to report the changes in hematologic, serum biochemical, plasma folate, B12 , and whole blood iron levels in dogs fed two different diets. METHODS: A pilot study was developed to compare the effects of a heat-processed high carbohydrate (HPHC) and nonprocessed high-fat (NPHF) diet. A total of 33 client-owned Staffordshire Bull Terriers were used; 18 had canine atopic dermatitis, seven were healthy, and eight were grouped as "borderline" dogs since they did not fulfill at least six of Favrot's criteria. The comparisons were made between the diet groups at the end visit of the diet intervention, as well as within the diet groups during the study. RESULTS: Significant differences between and within the diet groups were observed, although the majority of outcomes remained within the RIs. The median time of diet intervention was 140 days. Red blood cell counts, mean cell hemoglobin concentrations, and platelet counts were significantly higher, and mean cell hemoglobin, mean cell volume, alkaline phosphatase, inorganic phosphorus, and cholesterol were significantly lower in the dogs fed the NPHF diet compared with those fed the HPHC diet after the diet trial was completed. In addition, folate, B12 , and iron decreased significantly in the NPHF diet group. CONCLUSIONS: This pilot study indicated that diet had an impact on blood values, although most remained within RIs, pointing out the need for further studies.

Diet is a main source of vitamin D in Finnish pet rabbits (Oryctolagus cuniculus).

During the winter time in Finland, sunlight is inadequate for vitamin D synthesis. Many pet rabbits live as house rabbits with limited outdoor access even during summer and may therefore be dependent on dietary sources of vitamin D. The aims of this study were to report the serum 25-hydroxyvitamin D concentrations in Finnish pet rabbits and to identify factors that influence vitamin D status. Serum 25-hydroxyvitamin D concentrations from 140 pet rabbits were determined using a vitamin D enzyme immunoassay (EIA) kit. Eleven rabbits were excluded from the statistical analysis because of unclear dietary data. The remaining 129 rabbits were divided into groups depending on outdoor access during summer (no access n = 26, periodic n = 57, regular n = 46) as well as daily diet: little or no hay and commercial rabbit food ≤1/2 dl (n = 12); a lot of hay and no commercial food daily (n = 23); a lot of hay and commercial food <1 dl (n = 59); a lot of hay and commercial food ≥1 dl (n = 35). The range of serum 25-hydroxyvitamin D concentration was from 4.5 to 67.5 ng/ml with a mean of 26.1 ng/ml. Statistical general linear model adjusted for weight, age and season indicated that diet was associated with vitamin D concentrations (p = 0.001), but outdoor access during summer was not (p = 0.41). Mean 25-hydroxyvitamin D concentration was significantly higher in the rabbits receiving a lot of hay and commercial food ≥1 dl (33.9 ± 13.2 ng/ml) than in rabbits in other diet groups (24.0 ± 8.5 ng/ml, 21.7 ± 8.1 ng/ml, and 22.2 ± 18.0 ng/ml, respectively). This investigation showed wide variation in 25-hydroxyvitamin D concentrations among Finnish pet rabbits. Diet remains a main source since outdoor access seems to be too limited to provide adequate vitamin D synthesis for most of them, and the use of vitamin D supplements is rare.

Changes in biomarkers in equine synovial fluid two weeks after intra-articular hyaluronan treatment: a randomised double-blind clinical trial.

BACKGROUND: Inflammatory and degenerative activity inside the joint can be studied in vivo via analysis of synovial fluid (SF) biomarkers, which are molecular markers of inflammatory processes and tissue turnover. The aim of this study was to investigate the response of selected biomarkers in the SF after an intra-articular (IA) high-molecular-weight non-animal stabilized hyaluronic acid (NASHA) treatment. Our hypothesis was that prostaglandin E2 (PGE2), substance P, aggrecan chondroitin sulfate 846 epitope (CS846), and carboxypeptide of type II collagen (CPII) concentrations in SF would decrease more in the NASHA than in the placebo group. Twenty-eight clinically lame horses with positive responses to diagnostic IA anaesthesia of the metacarpophalangeal or metatarsophalangeal joints were randomized into treatment (n = 15) and control (n = 13) groups. After collection of baseline SF samples followed by IA diagnostic anaesthesia, horses in the treatment group received 3 ml of a NASHA product IA. Those in the placebo group received an equivalent volume of sterile 0.9% saline solution. The horses were re-evaluated and a second SF sample was obtained after a 2-week period. RESULTS: CS846 concentration decreased in the NASHA group only (P = 0.010). Both PGE2 and CPII concentrations decreased within the groups (PGE2, P = 0.010 for the NASHA group; P = 0.027 for the placebo group; CPII, P < 0.001 for NASHA group; P = 0.009 for placebo group). No significant treatment effect for any biomarker was found between groups. NASHA induced an increase in white blood cell count; this was significant compared with baseline (P = 0.021) and the placebo group (P = 0.045). CONCLUSIONS: Although the SF concentration of the cartilage-derived biomarker CS846 decreased in the NASHA group, no statistically significant treatment effect of any of the biomarkers were observed between treatment groups. The significant increase in SF white blood cell count after IA NASHA may indicate a mild inflammatory response. However, as no clinical adverse effects were observed, we conclude that IA NASHA was well tolerated.

Changes in energy metabolism, and levels of stress-related hormones and electrolytes in horses after intravenous administration of romifidine and the peripheral α-2 adrenoceptor antagonist vatinoxan.

BACKGROUND: Romifidine, an α-2 adrenoceptor agonist, is a widely-used sedative in equine medicine. Besides the desired sedative and analgesic actions, α-2 adrenoceptor agonists have side effects like alterations of plasma concentrations of glucose and certain stress-related hormones and metabolites in various species. Vatinoxan (previously known as MK-467), in turn, is an antagonist of α-2 adrenoceptors. Because vatinoxan does not cross the blood brain barrier in significant amounts, it has only minor effect on sedation induced by α-2 adrenoceptor agonists. Previously, vatinoxan is shown to prevent the hyperglycaemia, increase of plasma lactate concentration and the decrease of insulin and non-esterified free fatty acids (FFAs) caused by α-2 adrenoceptor agonists in different species. The aim of our study was to investigate the effects of intravenous romifidine and vatinoxan, alone and combined, on plasma concentrations of glucose and some stress-related hormones and metabolites in horses. RESULTS: Plasma glucose concentration differed between all intravenous treatments: romifidine (80 µg/kg; ROM), vatinoxan (200 µg/kg; V) and the combination of these (ROM + V). Glucose concentration was the highest after ROM and the lowest after V. Serum FFA concentration was higher after V than after ROM or ROM + V. The baseline serum concentration of insulin varied widely between the individual horses. No differences were detected in serum insulin, cortisol or plasma adrenocorticotropic hormone (ACTH) concentrations between the treatments. Plasma lactate, serum triglyceride or blood sodium and chloride concentrations did not differ from baseline or between the treatments. Compared with baseline, plasma glucose concentration increased after ROM and ROM + V, serum cortisol, FFA and base excess increased after all treatments and plasma ACTH concentration increased after V. Serum insulin concentration decreased after V and blood potassium decreased after all treatments. CONCLUSIONS: Romifidine induced hyperglycaemia, which vatinoxan partially prevented despite of the variations in baseline levels of serum insulin. The effects of romifidine and vatinoxan on the insulin concentration in horses need further investigation.

S100A12 concentrations and myeloperoxidase activities are increased in the intestinal mucosa of dogs with chronic enteropathies.

BACKGROUND: Intestinal mucosal S100A12 and myeloperoxidase (MPO) are inflammatory biomarkers in humans with inflammatory bowel disease (IBD). However, these biomarkers have not been studied in the intestinal mucosa of dogs with chronic enteropathies (CE), even though dogs with CE have increased S100A12 concentrations in feces and serum. This study investigated mucosal S100A12 concentrations and MPO activities in both dogs with CE and healthy Beagles. ELISA (S100A12 concentrations) and spectrophotometric methods (MPO activity) were used. The associations of both biomarkers with canine IBD activity index (CIBDAI), histopathologic findings, clinical outcome, and serum albumin concentrations were also investigated. We studied intestinal mucosal samples originating from different intestinal regions of 40 dogs with CE and 18 healthy Beagle dogs (duodenum, ileum, colon, and cecum). RESULTS: Compared with healthy Beagles, mucosal S100A12 concentrations in dogs with CE were significantly higher in the duodenum (p < 0.0001) and colon (p = 0.0011), but not in the ileum (p = 0.2725) and cecum (p = 0.2194). Mucosal MPO activity of dogs with CE was significantly higher in the duodenum (p < 0.0001), ileum (p = 0.0083), colon (p < 0.0001), and cecum (p = 0.0474). Mucosal S100A12 concentrations in the duodenum were significantly higher if the inflammatory infiltrate consisted mainly of neutrophils (p = 0.0439) or macrophages (p = 0.037). Mucosal S100A12 concentrations also showed a significant association with the severity of total histopathological injury and epithelial injury in the colon (p < 0.05). Mucosal MPO activity showed a significant association (p < 0.05) with the severity of total histopathological injury, epithelial injury, and eosinophil infiltration in the duodenum. There was no significant association of both biomarkers with CIBDAI or clinical outcome. CONCLUSIONS: This study showed that both mucosal S100A12 concentrations and MPO activities are significantly increased in the duodenum and colon of dogs with CE; mucosal MPO was also increased in the ileum and cecum. Future research should focus on assessing the clinical utility of S100A12 and MPO as diagnostic markers in dogs with CE.

A comparison of unheated loose housing with stables on the respiratory health of weaned-foals in cold winter conditions: an observational field-study.

BACKGROUND: Newly weaned horses in Finland are often moved to unheated loose housing systems in which the weanlings have free access to a paddock and a shelter. This practice is considered to be good for the development of young horses. The daily temperatures can stay below - 20 °C in Finland for several consecutive weeks during the winter season. However, the effect of unheated housing in a cold climatic environment on the respiratory health of weanlings under field conditions has not been studied before. This investigation was an observational field-study comprising 60 weanlings among 11 different voluntary participant rearing farms in Finland. Weanlings were either kept in unheated loose housing systems (n = 36) or in stables (n = 24) and were clinically examined on two separate occasions 58 days apart in cold winter conditions. RESULTS: The odds of clinical respiratory disease were lower in the older foals (loge days); OR = 0.009, P = 0.044). The plasma fibrinogen concentration was higher when the available space (m2/weanling) in the sleeping hall was smaller (P = 0.014) and it was lower when the sleeping hall was not insulated (P = 0.010). The plasma fibrinogen concentrations at the second examination were lower with a body condition score above 3 (P = 0.070). Standardbreds kept in loose housing systems had a lower body condition score than Finnhorses or Standardbreds kept in stables at both examinations (P = 0.026 and P = 0.007, respectively). Haemoglobin level was lower in weanlings in loose housing systems compared to their counterparts at the first examination (P = 0.037). Finnhorses had higher white blood cell count than Standardbreds at first (P = 0.002) and at the second examination (P = 0.001). CONCLUSIONS: Keeping weanling horses in cold loose housing systems does not seem to increase the occurrence of respiratory disease, but special attention should be focused on ventilation, air quality and feeding-practices. Our field study data suggest it might be advantageous to keep Standardbred foals born late in the season in a stable over the Finnish winter.

Toxicological characterisation of two novel selective aryl hydrocarbon receptor modulators in Sprague-Dawley rats.

The aryl hydrocarbon receptor (AHR) mediates the toxicity of dioxins, but also plays important physiological roles. Selective AHR modulators, which elicit some effects imparted by this receptor without causing the marked toxicity of dioxins, are presently under intense scrutiny. Two novel such compounds are IMA-08401 (N-acetyl-N-phenyl-4-acetoxy-5-chloro-1,2-dihydro-1-methyl-2-oxo-quinoline-3-carboxamide) and IMA-07101 (N-acetyl-N-(4-trifluoromethylphenyl)-4-acetoxy-1,2-dihydro-5-methoxy-1-methyl-2-oxo-quinoline-3-carboxamide). They represent, as diacetyl prodrugs, AHR-active metabolites of the drug compounds laquinimod and tasquinimod, respectively, which are intended for the treatment of autoimmune diseases and cancer. Here, we toxicologically assessed the novel compounds in Sprague-Dawley rats, after a single dose (8.75-92.5mg/kg) and 5-day repeated dosing at the highest doses achievable (IMA-08401: 100mg/kg/day; and IMA-07101: 75mg/kg/day). There were no overt clinical signs of toxicity, but body weight gain was marginally retarded, and the treatments induced minimal hepatic extramedullary haematopoiesis. Further, both the absolute and relative weights of the thymus were significantly decreased. Cyp1a1 gene expression was substantially increased in all tissues examined. The hepatic induction profile of other AHR battery genes was distinct from that caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The only marked alterations in serum clinical chemistry variables were a reduction in triglycerides and an increase in 3-hydroxybutyrate. Liver and kidney retinol and retinyl palmitate concentrations were affected largely in the same manner as reported for TCDD. In vitro, the novel compounds activated CYP1A1 effectively in H4IIE cells. Altogether, these novel compounds appear to act as potent activators of the AHR, but lack some major characteristic toxicities of dioxins. They therefore represent promising new selective AHR modulators.

Genetic Panel Screening of Nearly 100 Mutations Reveals New Insights into the Breed Distribution of Risk Variants for Canine Hereditary Disorders.

BACKGROUND: The growing number of identified genetic disease risk variants across dog breeds challenges the current state-of-the-art of population screening, veterinary molecular diagnostics, and genetic counseling. Multiplex screening of such variants is now technologically feasible, but its practical potential as a supportive tool for canine breeding, disease diagnostics, pet care, and genetics research is still unexplored. RESULTS: To demonstrate the utility of comprehensive genetic panel screening, we tested nearly 7000 dogs representing around 230 breeds for 93 disease-associated variants using a custom-designed genotyping microarray (the MyDogDNA® panel test). In addition to known breed disease-associated mutations, we discovered 15 risk variants in a total of 34 breeds in which their presence was previously undocumented. We followed up on seven of these genetic findings to demonstrate their clinical relevance. We report additional breeds harboring variants causing factor VII deficiency, hyperuricosuria, lens luxation, von Willebrand's disease, multifocal retinopathy, multidrug resistance, and rod-cone dysplasia. Moreover, we provide plausible molecular explanations for chondrodysplasia in the Chinook, cerebellar ataxia in the Norrbottenspitz, and familiar nephropathy in the Welsh Springer Spaniel. CONCLUSIONS: These practical examples illustrate how genetic panel screening represents a comprehensive, efficient and powerful diagnostic and research discovery tool with a range of applications in veterinary care, disease research, and breeding. We conclude that several known disease alleles are more widespread across different breeds than previously recognized. However, careful follow up studies of any unexpected discoveries are essential to establish genotype-phenotype correlations, as is readiness to provide genetic counseling on their implications for the dog and its breed.

Evaluating oxidative stress, serological- and haematological status of dogs suffering from osteoarthritis, after supplementing their diet with fish or corn oil.

BACKGROUND: Oxidative stress plays an important role in the pathogenesis of disease, and the antioxidant physiological effect of omega-3 from fish oil may lead to improvement of canine spontaneous osteoarthritis (OA). METHODS: In this prospective randomized, controlled, double-blinded study, we assessed haematological and biochemical parameters in dogs with OA following supplementation with either a concentrated omega-3 deep sea fish oil product or corn oil. Blood samples from 77 client-owned dogs diagnosed as having OA were taken before (baseline) and 16 weeks after having orally ingested 0.2 ml/Kg bodyweight/day of deep sea fish oil or corn oil. Circulating malondialdehyde (MDA), glutathione (GSH), non-transferrin bound iron (NTBI), free carnitine (Free-Car), 8-hydroxy-2-deoxyguanosine (8-OH-dG), and serum fatty acids, haemograms and serum biochemistry were evaluated. Differences within and between groups from baseline to end, were analysed using repeated samples T-test or Wilcoxon rank test and independent samples T-test or a Mann-Whitney test. RESULTS: Supplementation with fish oil resulted in a significant reduction from day 0 to day 112 in MDA (from 3.41 ± 1.34 to 2.43 ± 0.92 µmol/L; P < 0.001) and an elevation in Free-Car (from 18.18 ± 9.78 to 21.19 ± 9.58 µmol/L; P = 0.004) concentrations, whereas dogs receiving corn oil presented a reduction in MDA (from 3.41 ± 1.34 to 2.41 ± 1.01 µmol/L; P = 0.001) and NTBI (from -1.25 ± 2.17 to -2.31 ± 1.64 µmol/L; P = 0.002). Both groups showed increased (albeit not significantly) GSH and 8-OH-dG blood values. Dogs supplemented with fish oil had a significant reduction in the proportions of monocytes (from 3.84 ± 2.50 to 1.77 ± 1.92 %; P = 0.030) and basophils (from 1.47 ± 1.22 to 0.62 ± 0.62 %; P = 0.012), whereas a significant reduction in platelets counts (from 316.13 ± 93.83 to 288.41 ± 101.68 × 10(9)/L; P = 0.029), and an elevation in glucose (from 5.18 ± 0.37 to 5.32 ± 0.47 mmol/L; P = 0.041) and cholesterol (from 7.13 ± 1.62 to 7.73 ± 2.03 mmol/L; P = 0.011) measurements were observed in dogs receiving corn oil. CONCLUSIONS: In canine OA, supplementation with deep sea fish oil improved diverse markers of oxidative status in the dogs studied. As corn oil also contributed to the reduction in certain oxidative markers, albeit to a lesser degree, there was no clear difference between the two oil groups. No clinical, haematological or biochemical evidence of side effects emerged related to supplementation of either oil. Although a shift in blood fatty acid values was apparent due to the type of nutraceutical product given to the dogs, corn oil seems not to be a good placebo.

S100A12 concentrations and myeloperoxidase activity in the intestinal mucosa of healthy dogs.

BACKGROUND: Relatively few laboratory markers have been evaluated for the detection or monitoring of intestinal inflammation in canine chronic enteropathies, including inflammatory bowel disease (IBD). Previous research found that the intestinal mucosal levels of S100A12 and myeloperoxidase (MPO), as biomarkers of gut inflammation, were elevated in human patients with IBD. To date, the S100A12 and MPO levels in intestinal mucosal samples from either healthy dogs or from dogs suffering from IBD remain unreported. Therefore, this study aimed to evaluate the mucosal S100A12 and MPO levels in four different parts of the intestine (duodenum, jejunum, ileum and colon) in 12 healthy laboratory Beagle dogs using the ELISA and spectrophotometric methods, respectively. RESULTS: Based on histological examinations, the recorded findings for all the samples were considered normal. The mucosal concentration of S100A12 in the ileum was significantly higher than in all other segments of the intestine (p < 0.05). MPO activity was significantly higher in the ileal, jejunal and duodenal than in colonic mucosal samples (p < 0.05). Moreover, its concentration was higher in the jejunum than in the duodenum. CONCLUSIONS: This study showed that S100A12 and MPO are reliably detectable in canine intestinal mucosa. The assays used appeared to be sufficient to further evaluate the role of S100A12 and MPO in the pathogenesis of canine chronic enteropathies, including IBD. These biomarkers may play a role in the initial detection of gut inflammation suggesting the need for further investigations to confirm IBD or to differentiate between IBD subtypes. Understanding the role of S100A12 and MPO in the pathogenesis of chronic intestinal inflammation in future may result in an improved understanding of canine chronic intestinal inflammation.

Determination of the unsaturated disaccharides of hyaluronic acid in equine synovial fluid by high-performance liquid chromatography and fluorescence detection.

BACKGROUND: The purpose of this study was to develop and validate an analytical method to determine the presence of hyaluronic acid derived disaccharides in equine synovial fluid. FINDINGS: A high-performance liquid chromatography method for the determination of hyaluronic acid derived unsaturated disaccharides in equine synovial fluid was developed and validated. The method is based on the measurement of unsaturated disaccharides released by digestion of linear hyaluronic acid molecules. The method showed linearity (r(2) = 0.996) over the full working concentration range 0.89-30 mg/l. Relative standard deviation of intra- and inter-day precision ranged from of 4.3-6.7% and 7.1-7.8% respectively. The detection limit was 0.3 mg/l corresponding to 20 mg/l in synovial fluid. Accuracy of the assay was 97-103%. This method was evaluated by determining the concentration of unsaturated disaccharides from hyaluronic acid in synovial fluid of horses with lameness in the metacarpo-/metatarsophalangeal joint localized with positive response to intra-articular anesthesia. CONCLUSIONS: The described method is valid for determination of hyaluronic acid derived disaccharides in equine synovial fluid. This method was applied to a larger research project dealing with a new form of intra-articular therapy in horses with arthritic diseases.

Toxicological profile of ultrapure 2,2',3,4,4',5,5'-heptachlorbiphenyl (PCB 180) in adult rats.

PCB 180 is a persistent non-dioxin-like polychlorinated biphenyl (NDL-PCB) abundantly present in food and the environment. Risk characterization of NDL-PCBs is confounded by the presence of highly potent dioxin-like impurities. We used ultrapure PCB 180 to characterize its toxicity profile in a 28-day repeat dose toxicity study in young adult rats extended to cover endocrine and behavioral effects. Using a loading dose/maintenance dose regimen, groups of 5 males and 5 females were given total doses of 0, 3, 10, 30, 100, 300, 1000 or 1700 mg PCB 180/kg body weight by gavage. Dose-responses were analyzed using benchmark dose modeling based on dose and adipose tissue PCB concentrations. Body weight gain was retarded at 1700 mg/kg during loading dosing, but recovered thereafter. The most sensitive endpoint of toxicity that was used for risk characterization was altered open field behavior in females; i.e. increased activity and distance moved in the inner zone of an open field suggesting altered emotional responses to unfamiliar environment and impaired behavioral inhibition. Other dose-dependent changes included decreased serum thyroid hormones with associated histopathological changes, altered tissue retinoid levels, decreased hematocrit and hemoglobin, decreased follicle stimulating hormone and luteinizing hormone levels in males and increased expression of DNA damage markers in liver of females. Dose-dependent hypertrophy of zona fasciculata cells was observed in adrenals suggesting activation of cortex. There were gender differences in sensitivity and toxicity profiles were partly different in males and females. PCB 180 adipose tissue concentrations were clearly above the general human population levels, but close to the levels in highly exposed populations. The results demonstrate a distinct toxicological profile of PCB 180 with lack of dioxin-like properties required for assignment of WHO toxic equivalency factor. However, PCB 180 shares several toxicological targets with dioxin-like compounds emphasizing the potential for interactions.

Diagnostic evaluation and short-term outcome as indicators of long-term prognosis in horses with findings suggestive of inflammatory bowel disease treated with corticosteroids and anthelmintics.

BACKGROUND: Recurrent colic and unexplained weight loss despite good appetite and adequate feeding and management practices are common conditions in the horse. However, little information has been published on the systematic diagnostic evaluation, response to treatment, prognostic factors or outcome of either presentation. The aims of this study were to 1) identify possible prognostic indicators and 2) report the short- and long-term response to treatment with corticosteroid therapy of a variety of horses with a presumptive diagnosis of inflammatory bowel disease (IBD). Thirty-six horses with a history of recurrent colic and/or unexplained weight loss were screened with a detailed clinical, clinicopathological and diagnostic imaging examination. Twenty horses were subsequently selected that had findings consistent with inflammatory bowel disease based on the fulfilment of one or more of the following additional inclusion criteria: hypoproteinaemia, hypoalbuminaemia, malabsorption, an increased intestinal wall thickness on ultrasonographic examination or histopathological changes in rectal biopsy. These 20 horses were treated with a standardized larvicidal anthelmintic regime and a minimum of three weeks of corticosteroid therapy. RESULTS: The initial response to treatment was good in 75% (15/20) of horses, with a 3-year survival rate of 65% (13/20). The overall 3-year survival in horses that responded to initial treatment (12/15) was significantly higher (P = 0.031) than in those that did not respond to initial treatment (1/5). The peak xylose concentration was significantly (P = 0.048) higher in survivors (1.36 ± 0.44 mmol/L) than non-survivors (0.94 ± 0.36 mmol/L). CONCLUSIONS: The overall prognosis for long-term survival in horses with a presumptive diagnosis of IBD appears to be fair to moderate, and the initial response to anthelmintic and corticosteroid therapy could be a useful prognostic indicator. The findings of the present study suggest that a low peak xylose concentration in absorption testing is associated with a less favourable prognosis, supporting the use of this test.

Identification of matrix metalloproteinase-2 and -9 activities within intestinal mucosa of clinically healthy beagle dogs.

Matrix metalloproteinases (MMPs) 2 and 9 are zinc-dependent endopeptidases that contribute to the control of breakdown and reconstitution of extracellular matrix under both normal and pathological conditions. The main objective of this study was to identify the presence of MMP-2 and -9 in the mucosa of the small and large intestines of clinically healthy beagle dogs using gelatin zymography technique. Intestinal mucosa samples from four different parts of the intestine (duodenum, jejunum, ileum and colon) were taken from 12 healthy laboratory beagle dogs and examined histologically. Based on WSAVA histology standards, recorded findings of all samples were considered insignificant. Pro-MMP-2 and -9 activities were found in 17/48 (35%) and 25/48 (52%) of the samples, respectively. Among four different parts of the intestine of 12 dogs, the ileum had the highest positivity rates of 7/12 (58.3%) and 8/12 (66.7%) for pro-MMP-2 and -9 activities, respectively. However, statistical analysis showed no significant difference of pro-MMP-2 and -9 activities between the separate parts of the intestine (P>0.05). None of the intestinal samples showed gelatinolytic activity corresponding to the control bands of active MMP-2 and MMP-9. This study showed that pro-MMP-2 and -9 could be detected in the intestinal mucosa of healthy dogs using zymography, which seems to be a useful tool to evaluate the role of MMP-2 and -9 in the pathogenesis of canine chronic enteropathies, including inflammatory bowel diseases.

Development and validation of a gas chromatography-flame ionization detection method for quantifying sucrose in equine serum.

A simple and accurate method for quantifying sucrose in equine serum that can be applied to sucrose permeability testing in the horse was developed and validated using gas chromatography with flame ionization detection. The assay provided an acceptable degree of linearity, accuracy, and precision at concentrations of sucrose as low as 2.34 µmol/l and as high as 20.45 µmol/l. Percentage recovery of sucrose from serum ranged from 89% to 102%; repeatability and intermediate precision (relative standard deviation) ranged from 3.6% to 6.7% and 4.1% to 9.3%, respectively. The limit of detection was 0.73 µmol/l. No interfering peaks were observed except lactose, which gave 2 peaks, one of which overlapped partially with sucrose. To evaluate the suitability of the method for quantifying sucrose in serum samples from horses with naturally occurring gastric ulceration, 10 horses with and without naturally occurring gastric ulceration were subjected to sucrose permeability testing. All horses demonstrated an increase in serum sucrose concentration over time following oral administration of sucrose; however, the increase from baseline was significant for horses with gastric ulceration at 45 min (P = 0.0082) and 90 min (P = 0.0082) when compared with healthy horses. It was concluded that gas chromatography with flame ionization detection is a valid method for quantifying sucrose in equine serum and can be applied directly to the analysis of sucrose in equine serum as part of a larger validation study aimed at developing a blood test for the diagnosis of gastric ulcers in horses.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) increases bilirubin formation but hampers quantitative hepatic conversion of biliverdin to bilirubin in rats with wild-type AH receptor.

In haem degradation, haem oxygenase-1 (HO-1) first cleaves haem to biliverdin, which is reduced to bilirubin by biliverdin IXα reductase (BVR-A). The environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes hepatic accumulation of biliverdin in moderately TCDD-resistant line B (Kuopio) rats. Using line B and two TCDD-sensitive rat strains, the present study set out to probe the dose-response and biochemical mechanisms of this accumulation. At 28 days after exposure to 3-300 µg/kg TCDD in line B rats, already the lowest dose of TCDD tested, 3 µg/kg, affected serum bilirubin conjugates, and after doses ≥100 µg/kg, the liver content of bilirubin, biliverdin and their conjugates (collectively 'bile pigments') as well as HO-1 was elevated. BVR-A activity and serum bile acids were increased only by the doses of 100 and 300 µg/kg TCDD, respectively. Biliverdin conjugates correlated best with biliverdin suggesting it to be their immediate precursor. TCDD (100 µg/kg, 10 days) increased hepatic bilirubin and biliverdin levels also in TCDD-sensitive Long-Evans (Turku/AB; L-E) rats. Hepatic bilirubin and bile acids, but not biliverdin, were increased in feed-restricted L-E control rats. In TCDD-sensitive line C (Kuopio) rats, 10 µg/kg of TCDD increased the body-weight-normalized biliary excretion of bilirubin. Altogether, the results suggest that at acutely toxic doses, TCDD induces the formation of bilirubin in rats. However, concurrently, TCDD seems to hamper the quantitative conversion of biliverdin to bilirubin in line B and L-E rats' liver. Biliverdin conjugates are most likely formed as secondary products of biliverdin.

Impact of diets with a high content of greaves-meal protein or carbohydrates on faecal characteristics, volatile fatty acids and faecal calprotectin concentrations in healthy dogs.

BACKGROUND: Research suggests that dietary composition influences gastrointestinal function and bacteria-derived metabolic products in the dog colon. We previously reported that dietary composition impacts upon the faecal microbiota of healthy dogs. This study aims at evaluating the dietary influences on bacteria-derived metabolic products associated with the changes in faecal microbiota that we had previously reported. We fed high-carbohydrate starch based (HCS), [crude protein: 194 g/kg, starch: 438 g/kg], high-protein greaves-meal (HPGM), [crude protein: 609 g/kg, starch: 54 g/kg] and dry commercial (DC), [crude protein: 264 g/kg, starch: 277 g/kg] diets, and studied their effects on the metabolism of the colonic microbiota and faecal calprotectin concentrations in five Beagle dogs, allocated according to the Graeco-Latin square design. Each dietary period lasted for three weeks and was crossed-over with washout periods. Food intake, body weight, and faecal consistency scores, dry matter, pH, ammonia, volatile fatty acids (VFAs), and faecal canine calprotectin concentrations were determined. RESULTS: Faecal ammonia concentrations decreased with the HCS diet. All dogs fed the HPGM diet developed diarrhoea, which led to differences in faecal consistency scores between the diets. Faecal pH was higher with the HPGM diet. Moreover, decreases in propionic and acetic acids coupled with increases in branched-chain fatty acids and valeric acid caused changes in faecal total VFAs in dogs on the HPGM diet. Faecal canine calprotectin concentration was higher with the HPGM diet and correlated positively with valeric acid concentration. CONCLUSIONS: The HPGM diet led to diarrhoea in all dogs, and there were differences in faecal VFA profiles and faecal canine calprotectin concentrations.

Unexpected gender difference in sensitivity to the acute toxicity of dioxin in mice.

The acute toxicity of the ubiquitous environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) varies widely among species and strains. Previous studies in rats have established that females are approximately 2-fold more sensitive to TCDD lethality than males. However, there is a surprising gap in the literature regarding possible gender-related sensitivity differences in mice. In the present study, by using three substrains of TCDD-sensitive C57BL/6 mice and transgenic mice on this background, we demonstrated that: 1) in contrast to the situation in rats, female mice are the more resistant gender; 2) the magnitude of the divergence between male and female mice depends on the substrain, but can amount to over 10-fold; 3) AH receptor protein expression levels or mutations in the primary structure of this receptor are not involved in the resistance of female mice of a C57BL/6 substrain, despite their acute LD50 for TCDD being over 5000 µg/kg; 4) transgenic mice that globally express the rat wildtype AH receptor follow the mouse type of gender difference; 5) in gonadectomized mice, ovarian estrogens appear to enhance TCDD resistance, whereas testicular androgens seem to augment TCDD susceptibility; and 6) the gender difference correlates best with the severity of liver damage, which is also reflected in hepatic histopathology and the expression of pro-inflammatory cytokines, especially IL-6. Hence, the two closely related rodent species most often employed in toxicological risk characterization studies, rat and mouse, represent opposite examples of the influence of gender on dioxin sensitivity, further complicating the risk assessment of halogenated aromatic hydrocarbons.