Sinoatrial arrest associated with primary atrial myocarditis in a dog

The clinical findings in a dog with sinoatrial arrest, atrioventricular block and multifocal idioventricular escape beats are described. The clinical findings were associated with a primary myocarditis involving the sinoatrial node, the left and right atrium and atrioventricular node. The differentiation between sinoatrial arrest, sinoatrial block and sinoventricular conduction is discussed.     

Pharmacokinetics of dexamethasone following intra‐articular,intravenous, intramuscular,and oral administration in horses and its effects on endogenous hydrocortisone

Soma, L. R., Uboh, C. E., Liu, Y., Li, X., Robinson, M .A., Boston, R. C., Colahan, P. T. Pharmacokinetics of dexamethasone following intra‐articular, intravenous, intramuscular, and oral administration in horses and its effects on endogenous hydrocortisone. J. vet. Pharmacol. Therap.  36 , 181–191. This study investigated and compared the pharmacokinetics of intra‐articular (IA) administration of dexamethasone sodium phosphate (DSP) into three equine joints, femoropatellar (IAS), radiocarpal (IAC), and metacarpophalangeal (IAF), and the intramuscular (IM), oral (PO) and intravenous (IV) administrations. No significant differences in the pharmacokinetic estimates between the three joints were observed with the exception of maximum concentration (C_max) and time to maximum concentration (T_max). Median (range) C_max for the IAC, IAF, and IAS were 16.9 (14.6–35.4), 23.4 (13.5–73.0), and 46.9 (24.0–72.1) ng/mL, respectively. The T_max for IAC, IAF, and IAS were 1.0 (0.75–4.0), 0.62 (0.5–1.0), and 0.25 (0.08–0.25) h, respectively. Median (range) elimination half‐lives for IA and IM administrations were 3.6 (3.0–4.6) h and 3.4 (2.9–3.7) h, respectively. A 3‐compartment model was fitted to the plasma dexamethasone concentration–time curve following the IV administration of DSP; alpha, beta, and gamma half‐lives were 0.03 (0.01–0.05), 1.8 (0.34–2.3), and 5.1 (3.3–5.6) h, respectively. Following the PO administration, the median absorption and elimination half‐lives were 0.34 (0.29–1.6) and 3.4 (3.1–4.7) h, respectively. Endogenous hydrocortisone plasma concentrations declined from a baseline of 103.8 ± 29.1–3.1 ± 1.3 ng/mL at 20.0 ± 2.7 h following the administration of DSP and recovered to baseline values between 96 and 120 h for IV, IA, and IM administrations and at 72 h for the PO.     

景观格局对牛鹂泛性寄生的长期维持有影响么?(英文)

与大多数巢寄生鸟类不同,一些牛鹂(Molothrus spp.)可以广泛寄生于其分布区内的以及同一群落内的多种宿主;也没有证据表明,同一种群内的寄生个体对宿主物种有专一性。对此,进化滞后假说认为,与其他专性寄生的杜鹃和牛鹂相比,泛性寄生牛鹂是新近才进化的一支;而进化平衡假说则认为,由于寄生牛鹂的"黑手党"效应,宿主识别和拒绝牛鹂寄生卵的代价太大。然而,北美的许多宿主鸟类已进化出特定的反寄生防御行为,这些鸟类几乎都栖息在开阔地带,如草地、灌丛和溪流边。我们认为,北美鸟类生境的景观格局,对长期维持牛鹂的泛性寄生非常重要,同时也很好地解释了为什么北美森林宿主鸟类没有进化出反寄生行为。寄生性的牛鹂需要开阔草地觅食,因而很少见于森林。森林作为"源栖息地"产生的许多宿主,仅由于一些个体的扩散才进入寄生率和捕食风险都较高的片段化森林斑块,即"汇栖息地"。如此,宿主的反寄生行为的进化将非常缓慢,因为大部分个体都来自牛鹂寄生率很低的生境。此外,生境片段化、宿主繁殖扩散和集合种群的动态变化也进一步阻止了宿主反寄生行为的进化。只要北美大片的森林景观依然存在,这种状况就能持续,森林鸟类宿主对牛鹂寄生的反寄生行为就无法快速进化,反过来,牛鹂的泛性寄生也就得以维持。     

Diagnostic utility of computed tomography imaging in equine intracranial conditions

Reasons for performing study: The use of computer tomography (CT) and contrast‐enhanced CT (CCT) to image the head is common. However, the validity of CT as a neurodiagnostic indicator of intracranial diseases in horses is unknown. Objective: To define the validity of CT and CCT in horses with suspected intracranial disorders. Methods: The validity of CT imaging was estimated by comparing clinical, clinicopathological and histopathological findings to CT findings in 15 horses presented for intracranial disorders, for which pre‐ and post contrast CT images and post mortem examination of the brain and skull were reviewed. Post mortem examination (gross and histopathological examination) was considered as the gold standard; and sensitivity, specificity, predictive values, likelihood ratios, and pre‐ and post test probabilities were calculated. Results: All horses had abnormal neurological examinations on admission. Computer tomography imaging identified intracranial lesions in 8 horses, and included masses (oligodendroglioma, adenocarcinoma and cholesterinic granulomas), acute haemorrhage and skull fractures. Computer tomography imaging failed to identify intracranial lesions in 6 cases, which included meningitis, meningoencephalitis and nonacute haemorrhage. Lesions not recognised by CT were also not evident on gross examination but were identified by histopathological examination of the brain. Post mortem examination of the brain and skull was unremarkable in one horse, for which cranial CT imaging was normal (specificity, 100%). Therefore, the odds of having an intracranial lesion after an abnormal CT were very high. In contrast, there was a moderate sensitivity (57.1%, 95% confidence interval: 29.6–81.2). Conclusions and potential relevance: CT was an excellent neurodiagnostic tool in identifying skull fractures, intracranial space‐occupying lesions (e.g. neoplasia) and acute haemorrhage and allows to rule in intracranial disorders. However, CT showed limited sensitivity in identifying inflammatory disorders and small parenchymal lesions in the equine brain, which was not further detectable after contrast administration.     

Distribution of Cat Flea Larvae in the Carpeted Household Environment

Abstract— Cat flea egg production usually peaks during the night, coinciding with normal sleep periods for indoor pet dogs and cats. Adult flea feeding activity and the production of dried-blood feces is not correlated with the sleep activity of the host. Eggs and dried-blood feces fall or are dislodged from the pelage of the host at sleep or resting sites. In a case study example, cat flea hatched eggs, and larval exuviae were found to have a clumped distribution within household carpet. The spatial distribution of the immature stages were influenced by the habits of the pet host indoors. First- and second-in star larvae do not move far from the location of egg deposition and hatch. The movement of the larval stage is influenced by several factors in the environment, including pedestrian and pet traffic. The distribution of larvae in household carpeting is correlated with the sleeping habits of the host and egg deposition habits of the cat flea. Résumé— La production d'oeufs des puces de chat est maximale habituellement durant la nuit, coïncidant ainsi avec les périodes de sommeil des chiens et des chat. L'activité alimentaire des puces adultes et la production de fèces n'est pas corrélé avec la période de sommeil de l'hôte. Les oeufs et les excréments tombent ou sont détachés du pelage de l'hôte pendant le sommeil ou dans les zones de repos. Dans une étude, les oeufs des puces de chat éclos et les exuvies larvaires, ont une distribution groupée dans les tapis de la maison. La distribution spatiale des stades immatures sont influencées par les habitudes des animaux à l'intérieur. Les larves (stade I et II) ne peuvent pas se mouvoir loin du lieu du dépôt et d'éclosion des oeufs. Le mouvement des larves est influencé par divers facteurs de l'environnement, notamment les déplacements des personnes et des animaux. La distribution des larves dans les tapis de la maison est corrélée aux habitudes de sommeil de l'hôte et au dépôt des oeufs des puces du chat. [Robinson, W. H. Distribution of cat flea larvae in the carpeted household environment (Distribution des larves des puces du chat dans les tapis de la maison). Resumen— La producción de huevos en la pulga del gato alcanza su máximo nivel durante la noche, coincidiendo con los periodos normales de sueño de los perros y gatos de compañia. Los periodos de alimentación y de producción de heces de sangre seca de las pulgas adultas no coincide con el sueño del huésped. Los huevos y la heces de sangre seca caen o son eliminados del pelaje del huésped durante el sueño o en los lugares de descanso. En un estudio con casos clinicos, se observó que los huevos eclosionados de la pulga del gato y los restos de las larvas se encontraban en forma de agregados en la alformbra de la casa. La distribución espacial de los estadios inmaduros se veia influido por las costumbres del animal huésped dentro de la casa. En el primer y segundo estadío larvario no se desplazan lejos de donde se deposita y eclosiona el huevo. El movimiento de la larva se ve influido por varios factores del entorno, como el tráfico de personas y de animates. La distribución de larvas en las alfombras de la casa se correlaciona con los hábitos de sueño del huésped y con la deposición de huevos por la pulga. [Robinson, W. H. Distribution of cat flea larvae in the carpeted household environment (Distribución de larvas de la pulga del gato en viviendas enmoquetadas).     

The influence of ocean climate on coastal plankton and fish production

This study evaluates the influence of oceanic variability on plankton and fish production in a coastal upwelling system off southern Vancouver Island, British Columbia, Canada. A trophodynamics model is used to hind-cast plankton and fish production as estimated by empirical seasonal patterns in upwelling, sea surface temperature, solar radiation, and by biomasses of Pacific hake (Merluccius productus) and Pacific herring (Clupea pallasi). Simulation results indicate that interannual and longer-term variability in coastal plankton production occurs, and that the patterns are primarily determined by the dynamics in the initiation and intensity of coastal upwelling. Fish properties are greatly influenced by zooplankton, with simulated hake production being correlated with summer euphausiid production, and measured herring condition being correlated with autumn zooplankton production. An evaluation of transfer efficiencies indicates that interannual variability in the diatom-to-fish transfer is high (CV = 78%), with the majority of this variability occurring in the diatom-to-zooplankton component of the transfer. Seasonal dynamics of the diatom-to-zooplankton transfer result from the effects of upwelling on diatom production, and subsequent trophodynamic phasing with copepods and euphausiids.     

Persistent haematuria in a dog due to a discrete renal haemangioma

Persistent haematuria had been observed for 5 months in a 9-year-old male Collie. Investigation, including intravenous pyleography and selective arteriography, led to the presumptive diagnosis of a discrete left renal mass. The dog made an uneventful recovery after left nephrectomy. Histologically the lesion proved to be a medullary and pelvic haemangioma.