Olfactory responses of Amblyomma maculatum to rumen fluid and other odourants that attract blood-seeking arthropods.

Amblyomma maculatum Koch (Ixodida: Ixodidae) has emerged as a significant vector of human and companion animal diseases in the U.S.A. When expanding in range, A. maculatum can be difficult to collect in the field and control on livestock. A novel method is needed to improve the field collection of A. maculatum, as well as to control their effects as ectoparasites of livestock and companion animals. The present study aimed to test the effects of known volatiles on the activation and selection choices of A. maculatum in a laboratory-based Y-tube assay and field-based assays. Although the majority of adult A. maculatum were activated to move by five of the seven semiochemicals tested, only rumen fluid significantly attracted ticks to make a selection in the Y-tube apparatus. Rumen fluid attracted the most A. maculatum in the laboratory, with 56% (84/150) making it to the rumen Y-tube arm, although the results were not replicated in semi-field experiments. These studies highlight the need for continued work to identify attractants for tick vectors that will assist field collections. These attractants could also be incorporated into management strategies that lead to prevention technologies to reduce tick burdens on cattle or in risk areas of humans.

Genomic and antigenic characterization of bovine parainfluenza-3 viruses in the United States including modified live virus vaccine (MLV) strains and field strains from cattle.

This study investigated the genetic and antigenic characterization of parainfluenza-3 virus (PI3V) of cattle. Using molecular tests including real time PCR and viral genome sequencing, PI3V strains could be separated into PI3V types, including PI3V A, PI3V B, and PI3V C. Isolates from cattle with bovine respiratory disease clinical signs and commercial vaccines in the U.S. with MLV PI3V were typed using these molecular tests. All the MLV vaccine strains tested were PI3V A. In most cases PI3V field strains from calves receiving MLV vaccines were types heterologous to the vaccine type A. Also antigenic differences were noted as PI3V C strains had lower antibody levels than PI3V A in serums from cattle receiving MLV PI3V A vaccines. This study further demonstrates there is genetic variability of U.S. PI3V strains and also antigenic variability. In addition, isolates from cattle with BRD signs and receiving MLV vaccines may have heterologous types to the vaccines, and molecular tests should be performed to differentiate field from vaccine strains. Potentially the efficacy of current PI3V A vaccines should be evaluated with other types such a PI3V B and PI3V C.

Clinical, histopathological and metabolic responses following exercise in Arabian horses with a history of exertional rhabdomyolysis.

A previous report suggests a substantial incidence of exertional rhabdomyolysis (ER) in Arabian horses performing endurance racing. This study compared formalin histopathology and clinical and metabolic responses to a standardised field exercise test (SET) between Arabians with and without ER. Arabian horses with (n = 10; age 15.4 ± 5.6 years) and without (n = 9; 12.9 ± 6.1 years) prior ER were stall-rested for 24-48 h, after which paired ER and control horses were fitted with a telemetric ECG and performed a 47 min submaximal SET. Plasma glucose, lactate, electrolyte and total protein concentrations and packed cell volume were measured before and immediately after exercise. Blood and percutaneous gluteal muscle samples were also obtained before and 3 h after exercise for measurement of plasma creatine kinase (CK) activity and muscle glycogen concentration, respectively. Histopathologic analysis of formalin-fixed pre-exercise muscle sections was performed. Data were analyzed by ANOVA and non-parametric tests (P <0.05). No horses displayed clinical signs of ER during exercise, and plasma CK increased similarly in ER and control Arabians. Muscle glycogen, heart rate, and remaining plasma variables did not differ between horses with ER and control horses. Horses with ER had more internalised nuclei in mature myofibers, more aggregates of cytoplasmic glycogen and desmin, and higher myopathic scores than control horses. Although many horses with ER had histopathologic evidence of chronic myopathy, muscle glycogen concentrations and metabolic exercise responses were normal. Results did not support a consistent metabolic myopathy or a glycogen storage disorder in Arabians with ER.

Detection and characterization of viruses as field and vaccine strains in feedlot cattle with bovine respiratory disease.

This study investigated viruses in bovine respiratory disease (BRD) cases in feedlots, including bovine herpesvirus-1 (BoHV-1), bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), bovine coronaviruses (BoCV) and parainfluenza-3 virus (PI3V). Nasal swabs were collected from 114 cattle on initial BRD treatment. Processing included modified live virus (MLV) vaccination. Seven BRD necropsy cases were included for 121 total cases. Mean number of days on feed before first sample was 14.9 days. Swabs and tissue homogenates were tested by gel based PCR (G-PCR), quantitative-PCR (qPCR) and quantitative real time reverse transcriptase PCR (qRT-PCR) and viral culture. There were 87/114 (76.3%) swabs positive for at least one virus by at least one test. All necropsy cases were positive for at least one virus. Of 121 cases, positives included 18/121 (14.9%) BoHV-1; 19/121 (15.7%) BVDV; 76/121 (62.8%) BoCV; 11/121 (9.1%) BRSV; and 10/121 (8.3%) PI3V. For nasal swabs, G-PCR (5 viruses) detected 44/114 (38.6%); q-PCR and qRT-PCR (4 viruses) detected 81/114 (71.6%); and virus isolation detected 40/114 (35.1%). Most were positive for only one or two tests, but not all three tests. Necropsy cases had positives: 5/7 G-PCR, 5/7 q-PCR and qRT-PCR, and all were positive by cell culture. In some cases, G-PCR and both real time PCR were negative for BoHV-1, BVDV, and PI3V in samples positive by culture. PCR did not differentiate field from vaccines strains of BoHV-1, BVDV, and PI3V. However based on sequencing and analysis, field and vaccine strains of culture positive BoHV-1, BoCV, BVDV, and PI3V, 11/18 (61.1%) of BoHV-1 isolates, 6/17 (35.3%) BVDV isolates, and 1/10 (10.0%) PI3V identified as vaccine. BRSV was only identified by PCR testing. Interpretation of laboratory tests is appropriate as molecular based tests and virus isolation cannot separate field from vaccine strains. Additional testing using sequencing appears appropriate for identifying vaccine strains.

Systolic arterial blood pressure estimated by mitral regurgitation velocity, high definition oscillometry, and Doppler ultrasonography in dogs with naturally occurring degenerative mitral valve disease.

INTRODUCTION: To determine if systolic blood pressure estimated by mitral regurgitation (MR) velocity can be used interchangeably with that estimated by high definition oscillometry (HDO) and Doppler ultrasonography (DU) in dogs with naturally occurring mitral valve disease (MVD). ANIMALS: Forty-nine client-owned dogs with naturally occurring MVD. MATERIALS AND METHODS: This is a retrospective study. Medical records were reviewed and dogs with MR caused by degenerative MVD were included if systolic blood pressure was estimated from MR velocity determined by continuous wave Doppler (CW), DU and HDO at the same visit. A Pearson product moment correlation coefficient was determined for each combination of measures and tested for significance with a paired t-test. Limits of agreement between 2 measures were determined by the 95% confidence interval of the average difference of the means and illustrated by Bland-Altman plots. RESULTS: Systolic pressure estimated from CW was significantly but only moderately correlated to DU (r = 0.42, p=0.0015) and HDO (r = 0.40, p=0.0021). Pressure estimated from DU was significantly but only moderately correlated to HDO (r = 0.57, p≤0.0001). Limits of agreement were wide for all measures including DU and CW (-61.9to 44.6 mmHg), HDO and CW (-65.2to 26.9 mmHg), and HDO and DU (-63.1 to 42.06 mmHg). DISCUSSION: Systolic blood pressure estimated by CW cannot be used interchangeably with HDO or DU in dogs with naturally occurring MVD.

The effect of two doses of dried plum on bone density and bone biomarkers in osteopenic postmenopausal women: a randomized, controlled trial.

UNLABELLED: Daily consumption of 50 g of dried plum (equivalent to 5-6 dried plums) for 6 months may be as effective as 100 g of dried plum in preventing bone loss in older, osteopenic postmenopausal women. To some extent, these results may be attributed to the inhibition of bone resorption with the concurrent maintenance of bone formation. INTRODUCTION: The objective of our current study was to examine the possible dose-dependent effects of dried plum in preventing bone loss in older osteopenic postmenopausal women. METHODS: Forty-eight osteopenic women (65-79 years old) were randomly assigned into one of three treatment groups for 6 months: (1) 50 g of dried plum; (2) 100 g of dried plum; and (3) control. Total body, hip, and lumbar bone mineral density (BMD) were evaluated at baseline and 6 months using dual-energy X-ray absorptiometry. Blood biomarkers including bone-specific alkaline phosphatase (BAP), tartrate-resistant acid phosphatase (TRAP-5b), high-sensitivity C-reactive protein (hs-CRP), insulin-like growth factor-1 (IGF-1), and sclerostin were measured at baseline, 3 months, and 6 months. Osteoprotegerin (OPG), receptor activator of nuclear factor kappa-B ligand (RANKL), calcium, phosphorous, and vitamin D were measured at baseline and 6 months. RESULTS: Both doses of dried plum were able to prevent the loss of total body BMD compared with that of the control group (P < 0.05). TRAP-5b, a marker of bone resorption, decreased at 3 months and this was sustained at 6 months in both 50 and 100 g dried plum groups (P < 0.01 and P < 0.04, respectively). Although there were no significant changes in BAP for either of the dried plum groups, the BAP/TRAP-5b ratio was significantly (P < 0.05) greater at 6 months in both dried plum groups whereas there were no changes in the control group. CONCLUSIONS: These results confirm the ability of dried plum to prevent the loss of total body BMD in older osteopenic postmenopausal women and suggest that a lower dose of dried plum (i.e., 50 g) may be as effective as 100 g of dried plum in preventing bone loss in older, osteopenic postmenopausal women. This may be due, in part, to the ability of dried plums to inhibit bone resorption. This clinical trial was registered at ClinicalTrials.gov: NCT02325895 .

Preference and Performance of Hippodamia convergens (Coleoptera: Coccinellidae) and Chrysoperla carnea (Neuroptera: Chrysopidae) on Brevicoryne brassicae, Lipaphis erysimi, and Myzus persicae (Hemiptera: Aphididae) from Winter-Adapted Canola.

In the southern plains of the United States, winter-adapted canola (Brassica napus L.) is a recently introduced annual oilseed crop that has rapidly increased in hectares during the past 10 yr. Winter canola fields are infested annually with populations of Brevicoryne brassicae (L.) and Lipaphis erysimi (Kaltenbach), and these Brassica specialists are known to sequester plant volatiles from host plants, producing a chemical defense system against predators. Myzus persicae (Sulzer) is also common in winter canola fields, but as a generalist herbivore, does not sequester plant compounds. These three aphid species are expected to affect predator survival and development in very different ways. We conducted laboratory studies to 1) determine whether Hippodamia convergens (Guérin-Méneville) and Chrysoperla carnea (Stephens) larvae demonstrate feeding preferences among winter canola aphids and 2) describe the suitability of these prey species. Predators demonstrated no significant preference among prey, and each aphid species was suitable for predator survival to the adult stage. However, prey species significantly affected development times and adult weights of each predator species. Overall, predator development was delayed and surviving adults weighed less when provided with L. erysimi or B. brassicae, which sequestered high levels of indole glucosinolates from their host plants. Our results indicate that although common winter canola aphids were suitable prey for H. convergens and C. carnea, qualitative differences in nutritional suitability exist between Brassica-specialist aphids and the generalist M. persicae. These differences appear to be influenced by levels of sequestered plant compounds that are toxic to aphid predators.

Nasal isolation of Mannheimia haemolytica and Pasteurella multocida as predictors of respiratory disease in shipped calves.

Three hundred ninety five calves were purchased from sale barns and delivered to the Willard Sparks Beef Research Center. Nasal swabs were collected to determine if presence of Mannheimia haemolytica and Pasteurella multocida in the upper respiratory tract (URT) can facilitate diagnosis of bovine respiratory disease (BRD). Samples were collected at arrival and at treatment for BRD. Clinically healthy control calves were sampled at time of treatment of sick calves. M. haemolytica was more commonly isolated from calves at treatment than at time of arrival or from control calves. M. haemolytica was more common in calves requiring treatment than in those never treated. Need for treatment and number of treatments were negatively associated with average daily gain, supporting the accuracy of diagnosis. These results suggest that URT sampling, when combined with clinical diagnosis, may assist in providing greater diagnostic accuracy, improving ability to evaluate risk factors, interventions, and treatments.

Prevalence of exertional rhabdomyolysis in endurance horses in the Pacific Northwestern United States.

REASONS FOR PERFORMING STUDY: Exertional rhabdomyolysis (ER) is a reported syndrome in competing endurance horses; however, the prevalence and cause of ER in this population have not been defined. OBJECTIVES: To determine the prevalence of ER in a sample of endurance racing horses and investigate factors, including relevant genetic defects, contributing to the occurrence of rhabdomyolysis in this group. STUDY DESIGN: Prospective clinical study. METHODS: Riders of 101 horses participating in one of four 50-mile (80.5 km) distance races completed a comprehensive questionnaire regarding the medical history, management and performance of their horse. Serum creatine kinase activity (CK) was measured before and 4 h after completion of exercise. Hair samples were analysed by PCR for the R309H mutation in the glycogen synthase gene (GYS1) responsible for type 1 polysaccharide storage myopathy (PSSM) and the C7360G mutation in the ryanodine receptor 1 (RYR1) gene causing malignant hyperthermia (MH). RESULTS: Samples were obtained from 68 Arabians, 20 half-Arabians and 13 horses of other breeds. Serum CK was above the resting reference interval (145-633 u/l) in 38 horses after racing (median 883 u/l, range 658-3739) but was compatible with values previously reported in apparently healthy endurance horses. Pathological ER was suspected to occur in 4 horses with serum CK activities exceeding 10,000 u/l 4 h after racing (median 84,825 u/l; range 10,846-381,790) including 3 Arabians and one half-Arabian horse. GYS1 and RYR1 mutations were not present in hair samples from any horses. CONCLUSIONS: Exertional rhabdomyolysis occurred at a prevalence of 4.0% in a sample of horses participating in 50 mile distance events and all affected horses were Arabian or half-Arabian. The cause of ER in the endurance horse population remains unknown; however, ER in competing Arabian endurance horses is unlikely to be due to type 1 PSSM or MH.

The relevance of threaded external skeletal fixation pin insertion speed in canine bone with and without predrilling.

OBJECTIVES: The effects of insertion speed in revolutions per minute (RPM) and pilot hole predrilling for placement of threaded external skeletal fixation pins on temperature and morphological damage in cortical bone were evaluated. The null hypothesis states that insertion speed and predrilling will have no significant effect on temperature and morphological damage. METHODS: Fixation pins were inserted into cadaveric canine femurs at speeds of 700 RPM and 150 RPM, with and without pre-drilling. Temperature was measured at each cortex 0.5 mm and 3.0 mm from each insertion site. Samples were examined grossly and by scanning electron microscopy for evidence of morphological damage. Data were analysed for maximum temperature, temperature increase, sites above thermal necrosis thresholds, microcracks, thread quality and gross damage. RESULTS: Predrilling had a significant effect on maximum temperature, temperature increase, sites exceeding necrosis thresholds, microcracks, thread quality and gross damage. Speed of insertion had no significant effect on any of the measured parameters following predrilling, but had a significant effect on thread quality without predrilling. CLINICAL SIGNIFICANCE: Our results fail to reject the null hypothesis concerning insertion speed, which had no significant effect on thermal damage, and minimal effect on morphological damage, which was negated by predrilling. Our results reject the null hypothesis concerning predrilling and support the practice of predrilling fixation pin insertion sites.

Histologic characterization of the cat middle ear: in sickness and in health.

The purpose of this study was to establish microscopic normal in the middle ear of the cat while concurrently characterizing gross and microscopic lesions reflecting spontaneous otitis media. Both ears from 50 cats were examined grossly and processed for histologic examination of the external, middle, and internal ear on a single slide. Gross lesions of the middle ear were present in 14 of 100 (14%) and included turbid fluid, frank pus, hemorrhage, and fibrous thickening of the auricular mucoperiosteum. Histologically, 48 of 100 (48%) ears had evidence of ongoing or previous inflammatory middle ear disease, including proteinaceous fluid; vascular ectasia; expansion of the auricular mucoperiosteum by neutrophils, lymphocytes, and macrophages; cholesterol clefts; hemorrhage; fibrin; granulation tissue; membranous pseudo-glands; fibrosis; proliferation and/or osteolysis of the tympanic and septum bullae. Histologic lesions were identified in 34 of 100 ears (34%) lacking gross evidence of disease. Ears were classified histologically as either normal (52/100 [52%]) or diseased (48/100 [48%]). Diseased ears were further classified as mild to moderate (37/100 [37%]) or severely (11/100 [11%]) affected. Internal ear involvement was present in 11 of 100 (11%) ears. Histologic evidence of middle ear disease in cats is far greater than gross lesions or clinical literature suggests; further investigation and correlation of clinical and histologic disease are warranted. With minimal additional preparation, diagnostic specimens may be readily prepared and evaluated for this integral sensing organ.

Evaluation of efficacy of mineral oil, charcoal, and smectite in a rat model of equine cantharidin toxicosis.

BACKGROUND: The efficacy of orally administered therapeutics for the treatment of cantharidin intoxication has not been evaluated in controlled studies. OBJECTIVE: To develop a model of acute cantharidin intoxication in laboratory rats and to evaluate in this model the relative efficacy of 3 gastrointestinal therapies used to treat equine cantharidin toxicosis. ANIMALS: Sixty-four male Sprague-Dawley rats. METHODS: A blinded, randomized, controlled study was performed on rats surgically implanted with telemetry transmitters for evaluating heart rate, locomotor activity, and body temperature. Orogastric administration of cantharidin was performed within 15 seconds before administration of mineral oil, activated charcoal, or smectite. Negative control groups received therapeutic agents alone. Urine was collected for cantharidin analysis. Rats were sacrificed 24 hours after intoxication, and tissues were collected for histopathologic evaluation. Data analysis included ANOVA procedures and contingency tables. RESULTS: Six of 8 cantharidin-intoxicated rats treated with mineral oil died; bradycardia and hypothermia developed in the animals of this group 0-8 hours after intoxication. Rats treated with mineral oil had higher urine cantharidin concentrations than rats receiving cantharidin alone or with smectite (P = .04). The most severe hypothermia (30.6°C ± 1.0) developed in rats administered mineral oil at 4-8 hours after intoxication, whereas those treated with charcoal (35.2°C ± 0.8) had mean body temperatures higher than all other treatment groups (P = .03). Survival times in the charcoal (P = .16) and smectite (P = .12) treatment groups were not statistically different from negative controls. CONCLUSIONS AND CLINICAL IMPORTANCE: Mineral oil is often used in the treatment of equine cantharidin toxicosis. Our findings suggest that mineral oil increases cantharidin absorption, worsening morbidity and fatality in rats.

Determining host suitability of pecan for stored-product insects.

A no-choice test was performed to determine survival and reproductive capacity of stored-product insect pests on pecan, Carya illinoensis (Wangenheim) Koch. Insects used were Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae); sawtoothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Cucujidae); red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae); lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae); and rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae). Fifty adults of each beetle species or 10 reproductive pairs of P. interpunctella adults were placed in 0.5-liter containers with either whole-shell pecans, cracked-shell pecans, randomly selected in-shell pecans, pecan nutmeats, cracked wheat, or glass beads and held at 28 degrees C, 60-70% relative humidity, and 16:8 (L:D) photoperiod for 2, 4, 6, and 8 wk. Four replications of each insect-diet-interval combination were performed. Larvae of P. interpunctella, O. surinamensis, T. castaneum, C. ferrugineus, and adult P. interpunctella and O. surinamensis developed on cracked and nutmeat pecan diets. R. dominica did not complete reproduction on pecans. Knowledge that these pests can reproduce on stored pecan will assist pecan growers, accumulators, and storage facilities in preventing insect outbreaks on their product.

Cardiotoxicity, inflammation, and immune response after rattlesnake envenomation in the horse.

BACKGROUND: Cardiac abnormalities are reported in rattlesnake-bitten horses. The prevalence and cause are unknown. OBJECTIVES: To detect cardiac damage in rattlesnake-bitten horses by measuring cardiac troponin I (cTnI) and evaluating ECG recordings for presence of arrhythmias, and explore causes of this cardiac damage by measuring venom excretion, anti-venom antibodies, and tumor necrosis factor alpha (TNFα). ANIMALS: A total of 20 adult horses with a clinical diagnosis of rattlesnake bite and 6 healthy adult horses. METHODS: In a prospective clinical study, bite site swabs, blood samples, and urine samples were collected at various time points from 20 horses with a clinical diagnosis of snake bite. Continuous ECG recordings were obtained on the 20 affected horses and 6 normal control horses using 24-hour holter monitors. Plasma samples were assayed for cTnI, serum samples were assayed for TNFα and anti-venom antibodies, and bite site swabs and urine were assayed for venom. RESULTS: Forty percent of rattlesnake-bitten horses (8/20) experienced myocardial damage (increased cTnI). Seventy percent (14/20) experienced a cardiac arrhythmia. There was a positive correlation between cTnI and TNFα (P < .02). Horses with cTnI ≥ 2 ng/mL were more likely to have antibody titers >5,000 (P < .05). No correlations were found between venom concentration and cTnI, anti-venom antibody titers, TNFα, or presence of arrhythmias. CONCLUSIONS AND CLINICAL IMPORTANCE: Cardiac abnormalities in this population of horses indicate that cardiac damage after rattlesnake bite is common. Rattlesnake-bitten horses should be monitored for signs of cardiac damage and dysfunction. Long-term follow-up should be encouraged to detect delayed cardiac dysfunction.

Retrospective investigation of sudden maternal weight loss as an indicator of impending parturition in the term gravida: a pilot study.

The aim of the study was to perform a retrospective review of records to test a possible significant association between sudden, modest weight loss (≤2 lb) between the last two prenatal appointments in the late 3rd trimester and onset of labour. Hospital and clinic records were searched for women who delivered a term baby after the onset of natural labour between 2006 and 2008, in Tulsa, OK. High-risk pregnancies were excluded. Patients were categorised by whether they lost or gained weight between their last two prenatal appointments. The groups' average times to onset of spontaneous labour were compared. A total of 149 records were obtained. Mothers who lost weight had an average onset of spontaneous labour in 2.30 days; their counterparts' average was 2.34 days. Student's t-test and Wilcoxon test p values were 0.95 and 0.61, respectively. A Kolmogorov-Smirnov test p value was 0.2139. A one-half standard deviation difference in time to delivery, approximately 2.5 days, was detectable with 0.95 probability. It was concluded that these data may be the first time this question has been investigated and provide evidence that sudden, modest weight loss at the end of pregnancy is not associated with shorter time to onset of natural labour.

Efficacy of ozone fumigation against the major grain pests in stored wheat.

Field experiments were conducted in steel bins containing 13,600 kg of hard red winter wheat, Triiticum aestivum L. One bin was treated with ozone and the second bin served as a control. Stored grain insects were placed in bins for 1-, 2-, 3-, and 4-d exposure periods in sampling tubes to test ozone concentrations of 0, 25, 50, and 70 parts per million by volume (ppmv). Ozone treatments on eggs and larvae of Plodia interpunctella (Hübner) were not effective, but pupae were more susceptible. Sitophilus oryzae (L.) adults were the most susceptible species with 100% mortality reached after 2 d in all ozone treatments. However, some progeny were produced at all concentrations and exposure periods. Tribolium castaneum (Herbst) adults had 100% mortality only after 4 d at 50 or 70 ppmv. No T. castaneum progeny were produced after 2-4 d at 70 ppmv. For Rhyzopertha dominica (F.), Cryptolestes ferrugineus (Stephens), and Oryzaephilus surinamensis (L.), 100% mortality was never achieved and progeny were produced at all ozone concentrations. Laboratory experiments, testing the effectiveness of ozone in controlling psocids, were conducted in two polyvinyl chloride cylinders each containing 55 kg of hard red winter wheat. Ozone treatment at a concentration of 70 ppmv was highly effective against adult female Liposcelis bostrychophila Badonnel and Liposcelis paeta Pearman after only 1 d of exposure. However, it was not effective against eggs of both species at all exposure periods. Ozonation has potential for the control of some stored grain insect pests on wheat.

Gastritis in Alaskan racing sled dogs.

Alaskan racing sled dogs are a well-established model of exercise-induced gastric disease. The aim of this study was to define the temporal development of microscopical gastric lesions during long distance racing. Two groups of dogs were examined: group I comprised conditioned dogs that were exercising and group II were conditioned dogs not exercising. The gastric mucosa was examined endoscopically and sampled for routine histopathology and microscopical scoring, immunohistochemistry (IHC) and detection of apoptotic epithelial cells. Overall, group I dogs exhibited more significant epithelial lesions, including ulcers, compared with dogs in group II. Group II dogs exhibited the most severe mucosal inflammatory infiltrates. Although the intensity of inflammation differed, the nature of the inflammation was similar between groups, consisting of diffuse lymphocytic infiltration and a unique interface-type infiltrate that obscured the basement membrane zone and was accompanied by intraepithelial infiltration of lymphocytes. IHC confirmed the presence of CD3(+) T and CD79(+) B lymphocytes within the mucosal infiltrates; however, most of the intraepithelial and interface infiltrates were CD3(+) T cells. Spiral-shaped bacterial organisms were seen in the gastric tissues; however, their presence did not correlate with either the severity of epithelial lesions, inflammation or the pattern of interface inflammation. The number of apoptotic epithelial cells was widely variable and not significantly different between groups. These findings confirm previous observations that gastric ulcers develop in conditioned dogs under racing stress. The unique nature of the interface-type gastric inflammation is similar to that of human lymphocytic gastritis and may suggest an immune-mediated mechanism for the changes seen in Alaskan racing sled dogs.

Effect of feed restriction on plasma dantrolene concentrations in horses.

REASONS FOR PERFORMING STUDY: Dantrolene sodium is used to prevent exertional rhabdomyolysis in predisposed horses. Food intake might negatively impact dantrolene bioavailability in horses; however, prolonged feed restriction might be detrimental to performance. OBJECTIVE: To determine a minimum duration of feed restriction that would optimise plasma dantrolene concentrations in horses after nasogastric administration. It was hypothesised that feed restriction for 4, 8 or 12 h before dantrolene administration would result in higher plasma dantrolene concentrations than achieved with no feed restriction before treatment. METHODS: Five healthy horses were randomly rotated through 4 feed restriction periods of 0, 4, 8 and 12 h duration prior to nasogastric administration of dantrolene sodium (6 mg/kg bwt). Plasma dantrolene concentration was measured by spectrofluorometry at 60, 90, 120, 150, 180 and 210 min after administration. Data were analysed via repeated measures ANOVA. RESULTS: Peak plasma dantrolene concentration was highest when horses had 0 and 4 h of feed restriction (0.65 ± 0.10 µg/ml at 120 min; 0.66 ± 0.17 at 180 min, respectively) and was lower when horses were restricted from feed for 8 h (0.45 ± 0.15 at 150 min) and 12 h (0.21 ± 0.09 at 180 min). Mean plasma dantrolene concentration did not differ between 0 and 4 h feed restriction at any sample time, but feed restriction for 8 h resulted in significantly lower plasma dantrolene concentration at 60 and 180 min after treatment than when horses were restricted 0 and 4 h, respectively. Plasma dantrolene concentration was significantly lower at all sample times when horses were restricted from feed 12 h compared to 0 or 4 h. CONCLUSIONS: Absorption of nasogastrically administered dantrolene is inhibited by feed restriction before administration. To achieve optimal plasma dantrolene concentrations, feed restriction before oral administration should not exceed 4 h.

Reproductive parameters of the parthenogenetic psocid Lepinotus reticulatus (Psocoptera: Trogiidae) at constant temperatures.

We investigated effects of temperature, at 70% RH, on the reproductive parameters of the parthenogenetic psocid Lepinotus reticulatus Enderlein (Psocoptera: Trogiidae). The lowest fecundity (21) was at 35 degrees C and the highest (41) at 27.5 degrees C. At 22.5, 25, and 27.5 degrees C, peak oviposition rates (eggs/female/week) occurred in week 3 and were 4.7, 6.6, and 7.8, respectively; also 51, 57, and 62%, respectively, of all eggs were laid in the first 4 wk. At 30, 32.5, and 35 degrees C, peak oviposition rates occurred in week 2 and were 8.2, 9.0, and 7.4, respectively; 80, 85, and 98%, respectively, of all eggs were laid in the first 4 wk. The longest preoviposition period (4.4 d) was at 22.5 and 25 degrees C, and the longest postoviposition period (13.1 d) was at 22.5 degrees C. Oviposition period and longevity decreased with increasing temperature; at 22.5 degrees C, these parameters were 66 and 83 d, respectively, and at 35 degrees C, they were 18 and 24 d, respectively. Mean weekly oviposition rate increased with temperature and was highest at 32.5 degrees C (5.8 eggs/female/week). At 22.5, 25, 27.5, 30, 32.5, and 35 degrees C, it took 29, 20, 12, 11, 8, and 6 wk, respectively, for all females to die. Intrinsic rate of population increase increased with temperature until 32.5 degrees C (0.128) and then declined. We have developed temperature-dependent equations for preoviposition period, postoviposition period, oviposition period, oviposition rate, and longevity. Reproductive parameters affect population dynamics, and information on these parameters can be used in simulation models to predict L. reticulatus population dynamics to aid in developing effective management strategies.

Pulmonary histopathology of Cytauxzoon felis infections in the cat.

Cytauxzoonosis, caused by Cytauxzoon felis, is a regionally common, often fatal tick-borne disease primarily affecting the domestic cat. Retrospective analysis of case records from January 1995 to June 2005 identified 148 domestic cats diagnosed with cytauxzoonosis, having suitable archived lung sections. Lung sections were examined and graded on relevant parameters, the chief purpose of which was to characterize the pulmonary lesion of fatal feline cytauxzoonosis. Parameters were scored 0 to 3 for no lesion, mild, moderate, and severe, respectively. Evaluated parameters included the presence of interstitial pneumonia, increases in number of alveolar macrophages, degree of intra-alveolar hemorrhage, neutrophils infiltrating peribronchial and septal interstitium, and degree of vascular occlusion. Overall, interstitial pneumonia was moderate (1.72 +/- 0.65); alveolar macrophage numbers were mild (1.20 +/- 0.60); and intra-alveolar hemorrhage was mild (0.78 +/- 0.75). Neutrophil infiltrates were moderate (1.89 +/- 0.76), and vascular occlusion was moderate to severe (2.26 +/- 0.61). Pulmonary edema was common; its scoring was incorporated into the assessment for interstitial pneumonia. Interestingly, a thrombus was detected in the lung of 1 cat. The current understanding of the pathogenesis of cytauxzoonosis focuses on vascular occlusion by macrophages distended by megaschizont parasite stages within liver, spleen, and lung. These findings corroborate the current understanding yet shed light on the possibility that macrophage activation and inflammatory mediators lead to an interstitial pneumonic process characterized by neutrophilic infiltrates and pulmonary edema. These characterized lesions are likely correlative with the respiratory distress seen in affected cats.