Resistance of the Peripheral Nervous System to the Effects of Chronic Canine Hypothyroidism

Background: Hypothyroidism has been implicated in the development of multiple peripheral mono‐ and polyneuropathies in dogs. The objectives of this study were to evaluate the clinical and electrophysiologic effects of experimentally induced hypothyroidism on the peripheral nervous system of dogs. Hypothesis: Chronic hypothyroidism will induce peripheral nerve sensorimotor dysfunction. Animals: Eighteen purpose‐bred, female dogs. Methods: Prospective, longitudinal study: Hypothyroidism was induced by radioactive iodine administration in 9 dogs, and the remaining 9 served as untreated controls. Neurological examinations were performed monthly. Electrophysiologic testing consisting of electromyography (EMG); motor nerve conduction studies of the sciatic‐tibial, radial, ulnar, and recurrent laryngeal nerves; sciatic‐tibial and ulnar F‐wave studies; sensory nerve conduction studies of the tibial, ulnar, and radial nerves; and evaluation of blink reflex and facial responses were performed before and 6, 12, and 18 months after induction of hypothyroidism and compared with controls. Results: Clinical evidence of peripheral nervous dysfunction did not occur in any dog. At 6 month and subsequent evaluations, all hypothyroid dogs had EMG and histologic evidence of hypothyroid myopathy. Hypothyroid dogs had significant (P≤ .04) decreases in ulnar and sciatic‐tibial compound muscle action potentials over time, which were attributed to the concurrent myopathy. No significant differences between control and hypothyroid dogs were detected in electrophysiologic tests of motor (P≥ .1) or sensory nerve conduction velocity (P≥ .24) or nerve roots (P≥ .16) throughout the study period, with values remaining within reference ranges in all dogs. Conclusion: Chronic hypothyroidism induced by thyroid irradiation does not result in clinical or electrophysiologic evidence of peripheral neuropathy, but does cause subclinical myopathy.     

Evaluation of Transmittance and Reflectance Pulse Oximetry in a Canine Model of Hypotension and Desaturation

Ten, anesthetized dogs were instrumented with three pulse oximeter probes; two lingual transmittance probes and one rectal reflective probe. Arterial oxygen desaturation was produced by decreasing the inspired oxygen concentration. Hypotension was produced with an infusion of nitroprusside. Simultaneous pulse oximeter readings (SpO₂) were compared to co-oximeter measured arterial saturation (SaO₂) collected over a range of SaO₂ (50–100%) and mean arterial pressures (40–100mmHg). Each of the monitors and means of evaluating SpO₂ studied provided accurate SpO₂ measurements over a range of mean arterial pressure from 40–100mmHg. All of the monitors tested tended to overestimate the SaO₂ when the arterial saturation was less than 70%.     

Quantitative Ingrowth Analysis of a Porous-coated Acetabular Component in a Canine Model

Histomorphometric analysis of bone ingrowth into a porous-coated acetabular component was evaluated in a canine model. A total of nine prostheses were evaluated, 3 at 6 months, 3 at 12 months, and 3 at 24 months after implantation. All implants were grossly stable at the time of retrieval. The mean percentage of bone ingrowth was 12% at 6 months, 24% at 12 months, and 24% at 24 months. Narrow radiolucent lines noted on microradiographs were more evident at the 6 month time period than at the 12 or 24 month time periods. Bone ingrowth into a porous-coated acetabular component in a weight-bearing model may continue beyond the 6 month time period, and early evaluation of bone ingrowth may underestimate final bone ingrowth.     

Evaluation of a Joint Distractor to Facilitate Arthroscopy of the Canine Stifle

Objectives— To assess a novel technique for arthroscopic evaluation of the canine stifle avoiding the need for fat pad debridement.
Study Design— Prospective study.
Sample Population— Cadaveric canine stifles (n=10); Client-owned dogs (15).
Methods— In cadaveric stifles, the femoropatellar space was assessed before placement of a joint distractor and examination of the femorotibial joint. Time to complete evaluation of the femoropatellar space, to observe the cruciate ligaments, and to completion of examination of the femorotibial joint were recorded. Distractor-assisted arthroscopy was then performed in 15 consecutive clinical cases. Clinical information, time to complete joint evaluation, and ability to perform any additional arthroscopic surgery were recorded.
Results— Observation and palpation of intra-articular structures were possible in all cadaveric stifles. Mean time to evaluate the femoropatellar space was 3.2 minutes (range, 2–4 minutes); to observe the cruciate ligaments, 5.8 minutes (range, 3–8 minutes); and to completion of joint inspection, 9.1 minutes (range 6–13 minutes). In the clinical cases, observation of intra-articular structures was also possible in all stifles. Mean time to complete joint inspection was 21 minutes (range, 10–40 minutes). Partial meniscectomy was performed successfully in 5 stifles.
Conclusions— Use of a joint distractor allowed arthroscopic observation of all relevant structures. Partial meniscectomy was readily performed.
Clinical Relevance— Use of a joint distractor may simplify arthroscopic assessment of the canine stifle and avoid potential morbidity associated with fat pad debridement.     

Perineuronal Nets in the Central Nervous System

The remnant of ultimobranchial (UB) body in the thyroid gland of adult buffalo was studied. This remnant appeared in the form of irregular and elongated follicles of various size and shape with folded lumen. These structures occupied a peripheral location beneath the capsule, as well as being embedded mostly in the vascular connective tissue of the thyroid. Calcitonin cells were predominantly localized in the UB follicles. Scanning electron microscopy revealed that surface of most UB follicular cells was almost flat and polyhedral or hexagonal in shape. Other follicles possessed cells with dome shaped apical surface demarcated by a shallow intercellular depression. The luminal surface of the follicular cell lining was studded with microvilli that appeared with various density and length and were numerous at the cellular borders. Interestingly, most of UB follicular cells were provided with single cilium, projecting over the cell surface. Notably some UB follicles presented various stages of apocrine activities.     

Organisation of Autonomic Nervous Structures in the Small Intestine of Chinchilla (Chinchilla laniger,Molina)

Using histochemical, histological and immunocytochemical methods, organisation of the autonomic nerve structures in small intestine of chinchilla was investigated. Myenteric plexus was localised between circular and longitudinal layers of the smooth muscles. Forming network nodes, the small autonomic, cholinergic ganglia were linked with the bundles of nerve fibres. Adrenergic structures were visible as specific varicose, rosary‐like fibres forming bundles of parallel fibres connecting network nodes. Structures of the submucosal plexus formed a finer network than those of the myenteric plexus. Moreover, in ‘whole‐mount’ specimens, fibres forming thick perivascular plexuses were also observed. Immunocytochemical studies confirmed the cholinergic and adrenergic character of the investigated structures. VAChT‐positive neurones were found only in myenteric plexus, and numerous VAChT‐positive and DBH‐positive fibres were found in both plexuses.     

城市犬类管理制度探讨

在人类文明的发展史上,犬是不可缺少的助手,作为驯养动物,已有一万多年的历史了。随着中国经济的发展,近几年来,中国城乡居民养犬数量剧增,保守估计中国目前约有一亿多只犬[1]。北京、上海、广州、重庆和武汉被并称为"中国五大宠物城市"。由于     

一例泰迪犬冠状病毒感染伴发急性肺水肿的病理诊断报告

某宠物主人送检1只4月龄泰迪犬,初步确诊为冠状病毒感染,于输液过程中突然死亡。剖检可见整个肺脏呈深红色,肺叶边缘呈粉红色,切面深红色,支气管断端有大量红色液体渗出;剖开气管可见其浆膜面呈暗红色,腔内充满红色清亮液体;心脏左右心室扩张,质地柔软,心尖钝圆,呈心力衰竭心。对各个脏器取材进行病理组织学观察,主要病变表现为肺脏弥漫性淤血、水肿,心肌纤维局部溶解坏死。诊断该犬因感染冠状病毒后初次洗澡应激加重病情,并且随着大量静脉输液导致或加剧急性肺水肿发生,最终造成该犬急性死亡。对该病例进行了系统地病理剖检和组织病理学观察,为犬科动物和其他动物发生类似病症提供一定的参考。     

循环微粒在肺高压中的研究现状

肺高压预后差,治疗费用高,目前其确切发病机制尚不明确;循环微粒作为内皮受损的标志物,在肺高压的发生发展中的作用逐渐被人们所认识,本文将系统介绍循环微粒在肺高压中的研究现状,同时就未来肺高压的研究方向提出我们的设想。     

扎鲁司特对低温诱发的肉鸡肺动脉高压的影响

将60只雄性艾维茵商品代肉鸡常规育雏，17日龄随机分为3组：常温对照组(常温组)、低温模型组(低温组)和低温扎鲁司特组(扎鲁司特组)。各组于处理后14d(31日龄)和21d(38日龄)分别用右心导管法及直接导管法测定扎鲁司特对肺动脉压(PAP)和股动脉压(FAP)的影响，同时测定红细胞压积(PCV)和腹水心脏指数(AHI)。结果：(1)在低温环境的早期，扎鲁司特使肉鸡肺动脉收缩压和舒张压均升高，后期仅使舒张压升高；(2)扎鲁司特使PCV升高，增加了血液黏性阻力；(3)扎鲁司特使AHI升高，促进右心肥大；(4)扎鲁司特对股动脉压无显著性影响。可见扎鲁司特促进了肉鸡肺动脉高压综合征的发生发展。     

肺血管结构重建与肉鸡肺动脉高压形成的关系

为探讨肺血管重建与肉鸡肺动脉高压形成的关系及肺外动脉舒张反应下降的原因,研究观察比较了正常鸡、亚临床腹水鸡和腹水鸡肺血管形态学上的变化。结果显示:腹水鸡和亚临床腹水鸡各种管径肺动脉的中膜都比正常鸡厚,而腹水鸡的又比亚临床腹水鸡的厚;肺动脉相对中膜厚度和相对中膜面积都与RV/TV呈极显著相关(P<0 001),并与mPAP、mRVP、LeadⅡS和SaO2呈显著或极显著相关(P<0 01,P<0 001)。对腹水鸡和亚临床腹水鸡肺外动脉的病理组织学观察结果为:随肺动脉压升高,肺外动脉内皮损伤逐渐严重,内膜逐渐纤维化和增生、增厚,并使整个管壁纤维化和增厚,内皮至平滑肌的间隙逐渐增宽,由大量成纤维细胞、结缔组织和胶原纤维组成。结果说明:以肺动脉中膜肥厚为特征的肺血管结构重建与肺动脉高压、右心肥大的关系极为密切,是导致肉鸡肺动脉高压发生发展的主要形态学因素;组织学上的结构变化使血管顺应性下降可能是造成肺外动脉对舒血管物质的舒张反应性下降的原因,非NO释放下降造成的。     

益生菌牙膏缓解犬牙菌斑和牙结石的研究

[目的] 评价某公司生产的一款宠物用益生菌牙膏对犬牙菌斑和牙结石形成的缓解功效。[方法] 选取口腔健康、体况良好的成年比格犬10只,配对设计随机分为阴性对照组（n=5）和益生菌牙膏组（n=5）;阴性对照组仅饲喂犬粮,益生菌牙膏组每次餐后给予约4 g/只益生菌牙膏,每天2次,连续使用28 d;试验第0天对所有试验犬牙齿进行洁牙抛光处理,试验第14天和第29天分别对比格犬牙菌斑进行评分,第29天对牙结石进行评分并检测口腔气体挥发性化合物（H₂S+CH₃SH）浓度;当牙菌斑和牙结石评分均值以及口腔气体挥发性化合物浓度均值减少幅度≥15%时,定义为益生菌牙膏效果显著。[结果] 与阴性对照组相比,益生菌牙膏组在给予益生菌牙膏第14天时,牙菌斑评分均值减少幅度为-0.36%（P>0.05）,第29天牙菌斑评分均值减少幅度为21.47%（P<0.05）;第29天益生菌牙膏组牙结石评分均值减少幅度为6.54%（P>0.05）;第29天益生菌牙膏组犬口腔气体挥发性化合物浓度均值减少幅度为-44.59% （P>0.05）。[结论] 在试验期内,该款益生菌牙膏能够有效抑制犬牙菌斑的形成,但不具有减少牙结石形成和降低口腔气体挥发性化合物浓度的功效。     

Evaluation of a Collagenase Generated Osteoarthritis Biomarker in Naturally Occurring Canine Cruciate Disease

Objective— To determine the clinical value of a novel osteoarthritis (OA) biomarker in detecting canine cruciate disease.
Study Design— Cross sectional clinical study.
Animals— Dogs (n=22) with cranial cruciate ligament (CCL) rupture and 12 control dogs.
Methods— Concentrations of collagenase-generated cleavage epitope of type II collagen (Col2-3/4C_{long mono}, or C2C) in serum, urine, and joint fluid were compared between a group of dogs with CCL rupture and a control group. Correlation of C2C concentrations to the clinical stage of stifle OA was also evaluated.
Results— There were no significant differences in C2C concentrations in serum, urine, and joint fluid between groups ( P >.05). Subjective scores of lameness, joint effusion, osteophytosis were significantly more severe in the CCL rupture group compared with the control group ( P <.05). There was no significant correlation of C2C concentrations with clinical stage of stifle OA ( P >.05).
Conclusion— This OA biomarker did not detect pathology associated with CCL rupture. Our results suggest that collagenase-specific degradation of type II collagen in articular cartilage may not be involved in the early stage of naturally occurring canine cruciate disease, and that pathology associated with naturally occurring CCL rupture is different from that of experimental OA model.
Clinical Relevance— C2C is not clinically useful in detecting CCL rupture in dogs.