Comparative effects of three different ventilatory treatments on arterial blood gas values and oxygen extraction in healthy anaesthetized dogs

ObjectiveTo compare the effect of invasive continuous positive airway pressure (CPAP), pressure-controlled ventilation (PCV) with positive end-expiratory pressure (PEEP) and spontaneous breathing (SB) on PaO₂, PaCO₂ and arterial to central venous oxygen content difference (CaO₂-CcvO₂) in healthy anaesthetized dogs.Study designProspective randomized crossover study.AnimalsA group of 15 adult male dogs undergoing elective orchidectomy.MethodsDogs were anaesthetized [buprenorphine, medetomidine, propofol and isoflurane in an air oxygen (FiO₂= 0.5)]. All ventilatory treatments (CPAP: 4 cmH₂O; PCV: 10 cmH₂O driving pressure; PEEP, 4 cmH₂O; respiratory rate of 10 breaths minute^–1 and inspiratory-to-expiratory ratio of 1:2; SB: no pressure applied) were applied in a randomized order during the same anaesthetic. Arterial and central venous blood samples were collected immediately before the start and at 20 minutes after each treatment. Data were compared using a general linear mixed model (p < 0.05).ResultsMedian PaO₂ was significantly higher after PCV [222 mmHg (29.6 kPa)] than after CPAP [202 mmHg (26.9 kPa)] and SB [208 mmHg (27.7 kPa)] (p < 0.001). Median PaCO₂ was lower after PCV [48 mmHg (6.4 kPa)] than after CPAP [58 mmHg (7.7 kPa)] and SB [56 mmHg (7.5 kPa)] (p < 0.001). Median CaO₂-CcvO₂ was greater after PCV (4.36 mL dL^–1) than after CPAP (3.41 mL dL^–1) and SB (3.23 mL dL^–1) (p < 0.001). PaO₂, PaCO₂ and CaO₂-CcvO₂ were no different between CPAP and SB (p > 0.99, p = 0.697 and p = 0.922, respectively).Conclusions and clinical relevanceCPAP resulted in similar arterial oxygenation, CO₂ elimination and tissue oxygen extraction to SB. PCV resulted in improved arterial oxygenation and CO₂ elimination. Greater oxygen extraction occurred with PCV than with CPAP and SB, offsetting its advantage of improved arterial oxygenation. The benefit of invasive CPAP over SB in the healthy anaesthetized dog remains uncertain.     

Quantification of nasal airflow resistance in English bulldogs using computed tomography and computational fluid dynamics

Stenotic nares, edematous intranasal turbinates, mucosal swelling, and an elongated, thickened soft palate are common sources of airflow resistance for dogs with brachycephalic airway syndrome. Surgery has focused on enlarging the nasal apertures and reducing tissue of the soft palate. However, objective measures of surgical efficacy are lacking. Twenty‐one English bulldogs without previous surgery were recruited for this prospective, pilot study. Computed tomography was performed using conscious sedation and without endotracheal intubation using a 128 multidetector computed tomography scanner. Raw multidetector computed tomography data were rendered to create a three‐dimensional surface mesh model by automatic segmentation of the air‐filled nasal passage from the nares to the caudal soft palate. Three‐dimensional surface models were used to construct computational fluid dynamics models of nasal airflow resistance from the nares to the caudal aspect of the soft palate. The computational fluid dynamics models were used to simulate airflow in each dog and airway resistance varied widely with a median 36.46 (Pa/mm)/(l/s) and an interquartile range of 19.84 to 90.74 (Pa/mm)/(/s). In 19/21 dogs, the rostral third of the nasal passage exhibited a larger airflow resistance than the caudal and middle regions of the nasal passage. In addition, computational fluid dynamics data indicated that overall measures of airflow resistance may significantly underestimate the maximum local resistance. We conclude that computational fluid dynamics models derived from nasal multidetector computed tomography can quantify airway resistance in brachycephalic dogs. This methodology represents a novel approach to noninvasively quantify airflow resistance and may have utility for objectively studying effects of surgical interventions in canine brachycephalic airway syndrome.     

金雀花碱的生物活性研究进展

金雀花碱(Cytisine,Cyt)是一种主要存在于豆科毒豆属植物种子中的喹诺里西啶生物碱。近年来金雀花碱的多种生物活性被逐渐发掘,其具有戒烟、促呼吸、镇痛、抗肿瘤等功效。在抗癌活性方面能够诱导癌细胞凋亡,已被广泛应用于抑制多种肿瘤细胞的增殖;在戒烟方面能够作为选择性局部激动剂,降低吸烟者对尼古丁的依赖,有望广泛应用于戒烟;在镇痛方面能够反射性的兴奋呼吸,已被广泛应用于临床手术对患者的麻醉作用。本文通过对大量文献的查阅及验证,将对金雀花碱的生物活性及其相关作用机制进行总结,以期为金雀花碱的开发和利用提供理论基础。     

Comparison of the cognitive palatability assessment protocol and the two-pan test for use in assessing palatability of two similar foods in dogs

OBJECTIVE: To compare preferences of dogs for 2 similar foods by use of 2 distinct methods (the cognitive palatability assessment protocol [CPAP] and the 2-pan test). ANIMALS: 13 Beagles. PROCEDURE: 6 dogs were trained in a 3-choice object-discrimination-learning task in which their nonpreferred objects were associated with a reward of a lamb-based or chicken-based food. The number of choices for each object was used to determine food preferences. Preference of the same foods was also assessed by use of a 2-pan test in which all 13 dogs were provided the 2 foods in identical bowls. The amount of each food consumed in 10 minutes was used to determine food preference. RESULTS: All dogs had a noticeable preference for the chicken-based food during the CPAP. Once established, preferences remained consistent and were not affected by satiety. The 2-pan test identified a preference for the chicken-based food in dogs with previous exposure to the food but only a weak and nonsignificant preference for the same food in dogs without previous exposure. Food preferences in the 2-pan test varied considerably. Total food consumption and the ability to detect a preference were reduced when dogs were fed prior to testing. CONCLUSIONS AND CLINICAL RELEVANCE: The CPAP provides a reliable measure of food preference that requires few test subjects. The 2-pan test reveals similar preferences but with variability in data that requires larger numbers of subjects and is susceptible to effects from prior exposure and feeding of the test foods to the subjects.     

Quantitative bacterial cultures and cytological examination of bronchoalveolar lavage specimens in dogs

Cytology and quantitative bacterial cultures of lower respiratory tract secretions are widely used in human medicine to differentiate airway infection from simple bacterial colonization. A retrospective study was conducted to determine the usefulness of quantitative aerobic cultures and Gram stain intracellular bacteria counts from bronchoalveolar lavage (BAL) specimens in dogs in diagnosing lower respiratory tract infection (LRTI) and to determine whether chronic bronchitis is associated with marked bacterial growth in dogs. The threshold determined to define clinically relevant bacterial growth was 1.7 x 10(3) colony-forming units per milliliter of BAL fluid. We used this threshold and found that diagnostic sensitivity and specificity were 86% and 100%, respectively. With a threshold for infection of >2 intracellular bacteria observed in any of 50 fields, microscopic examination of Gram stain BAL preparations had a sensitivity of 71% and a specificity of 97% in establishing LRTI. There was a high correlation between bacterial morphology on BAL Gram stain and bacterial cultures. Combining the results of intracellular bacteria counts from the BAL Gram stain with those from the quantitative cultures, the sensitivity in diagnosing LRTI was 87% and the specificity was 97%. BAL quantitative cultures as well as quantitating intracellular bacteria on Gram stain BAL cytology were revealed to be useful in identifying LRTI in dogs. Chronic bronchitis does not appear to be associated with marked bacterial growth in dogs.     

Near-fatal misuse of medical tape around an endotracheal tube connector during inhalation anesthesia in a horse

A 7-year-old gelded Irish sports horse weighing 650 kg was anesthetized on 2 consecutive days for lavage of a septic right radio-carpal joint. On both occasions the endotracheal tube connector, which had been bound in medical tape to produce an airtight seal, functioned as a unidirectional valve during mechanical ventilation, retarding expiration, imposing positive end expiratory pressure (PEEP), and probably continuous positive airway pressure (CPAP). The equipment dysfunction was not identified on either occasion despite close inspection prompted by progressive increases in airway pressure and thoracic distension. Whilst the PEEP and CPAP exerted unexpectedly modest cardiovascular effects and the horse recovered uneventfully on both occasions, the improvisation may have proven fatal in a higher-risk subject.     

Continuous positive airway pressure administered via face mask in tranquilized dogs

Objective – To evaluate the tolerance of a continuous positive airway pressure (CPAP) mask in tranquilized dogs and compare PaO₂ in arterial blood in dogs receiving oxygen with a regular face mask or CPAP mask set to maintain a pressure of 2.5 or 5 cm H₂O. Design – Prospective, randomized clinical study. Setting – University teaching hospital. Animals – Sixteen client‐owned dogs without evidence of cardiopulmonary disease were studied. Interventions – Eight animals were randomly assigned to each of 2 treatment groups: group A received 2.5 cm H₂O CPAP and group B received 5 cm H₂O CPAP after first receiving oxygen (5 L/min) by a regular face mask. Animals were tranquilized with acepromazine 0.05 mg/kg, IV and morphine 0.2 mg/kg, IM. An arterial catheter was then placed to facilitate blood sampling for pHa, PaO₂, and PaCO₂ determinations before and after treatments. Direct mean arterial pressure, heart rate, respiratory rate, and temperature were also recorded after each treatment. Measurements and Main Results – CPAP administration was well tolerated by all animals. The mean arterial pressure, heart rate, respiratory rate, temperature, PaCO₂, and pHa, did not differ at any time point between groups. Differences were seen in oxygenation; in group A, PaO₂ significantly increased from a mean of 288.3±47.5 mm Hg with a standard mask to a mean of 390.3±65.5 mm Hg with the CPAP mask and in group B, PaO₂ increased similarly from 325.0±70.5 to 425.2±63.4 mm Hg (P<0.05); no differences were detected between the 2 CPAP treatments. Conclusions – In healthy tranquilized dogs noninvasive CPAP is well tolerated and increases PaO₂ above values obtained when using a regular face mask.     

免疫组织化学技术在兽医诊断中的应用

免疫组织化学技术是利用抗原抗体特异性结合的原理,将物质标记在抗体上,通过标记来显示抗原抗体复合物的存在。随着免疫组织化学技术的发展和成熟,已被广泛应用于兽医诊断中,除用于对病原体准确的检测外,主要用于病原在机体组织中的定位和动态分布特点研究、新病原的发现、活体动物中病原的检测、以及对固定组织进行回顾性研究等,是广泛使用的现代病理学研究手段之一。     

牛活体采卵技术研究进展

活体采卵(Ovum Pick-up,OPU)可生产大量遗传品质优良、系谱明确的体外受精胚胎,成为牛胚胎移植的重要胚胎来源,在奶牛和肉牛生产中得到广泛应用。本文综述了牛OPU技术特点和优势,重点分析了影响OUP效率的因素,以期为牛OUP胚胎生产提供参考。     

小鼠细菌性乳腺炎模型研究进展

奶牛细菌性乳腺炎一直是困扰奶牛养殖业的一大难题,给奶牛养殖行业造成巨大经济损失,直接危害奶牛健康。为有效治疗奶牛细菌性乳腺炎,研究人员需要通过动物模型来进行相关研究,以期找到优良的治疗方法。随着动物模型多年的探索与使用,小鼠细菌性乳腺炎模型因具有省时、省力以及性价比高的优点获得了研究人员的广泛认可,被大量用于相关研究中。就此对小鼠细菌性乳腺炎模型的建立、特点以及应用进行综述,旨在为细菌性乳腺炎相关研究提供参考。     

低聚木糖在畜牧生产中的应用研究

低聚木糖是一种新型饲料添加剂,具有促进肠道有益菌增殖、吸附肠道病原菌、提高机体免疫力、促进脂类代谢和矿物质代谢以及抗氧化等作用。低聚木糖作为饲料添加剂在饲料工业中的应用也得到肯定,已广泛应用于猪、禽、反刍动物和水产动物等饲料。研究结果证实,低聚木糖能够改善动物生产性能、提高动物机体免疫力和抗病力,另外,添加低聚木糖还可以降低饲料中的药物用量,降低药物残留,有利于环保。主要介绍了低聚木糖的化学结构和理化特性、作用机理以及在畜牧业生产中的应用效果,并进行了前景展望。     

动物性食品中磺胺类药物残留检测方法的研究进展

动物性食品中兽药和饲料添加剂残留对人体健康所造成的危害,已经引起世界范围的广泛关注,成为人类亟待解决的问题之一。磺胺类药物特别是磺胺嘧啶、磺胺甲基嘧啶、磺胺二甲氧嘧啶、磺胺甲基异口恶唑等作为饲料添加剂或动物疫病治疗药物被广泛应用,然而不合理的用药导致磺胺类药物在动物性食品中残留,影响食品安全,进而危害人类健康。作者对目前动物性食品中磺胺类药物（SAs）残留的主要检测方法进行介绍,主要包括微生物检测法、分光光度计法、免疫分析法、色谱法及色/质联用技术等,重点介绍了免疫分析法和色谱法,并对各种检测方法做出评价及其发展趋势进行了展望。     

实时B型超声扫描在绵羊妊娠监测中的应用

随着超声诊断技术的不断发展，它在兽医领域的应用也越来越广泛。目前，B型超声主要用于对动物妊娠期子宫和胎儿的监测，关于牛、羊、猪、马、犬、等动物都有应用B型超声监测妊娠的大量报道。本文仅就B型超声在绵羊早期妊娠诊断、怀胎数的判断及判断胎龄三方面进行综述。     

体外授精技术研究百年历史回顾

自从1878年,Schenk在家兔和豚鼠上进行体外授精(invitrofertilization,IVF)尝试开始至今,哺乳类物种IVF技术已经有120多年的历史,尽管该项技术因不同目的被广泛应用,但对其发展前景的研究和评价相对较少。本文通过回顾一些具有重要历史意义的试验研究,分析IVF技术的发展历程,为IVF的深入研究提供历史之鉴,并应用于科学试验研究。     

毛细管电泳技术在兽药和农药残留检测中的应用

随着养殖业和农业的发展,兽药和农药残留对食品安全的危害日益受到人们的重视,由于检测技术的不断完善,多残留检测技术已逐渐占据残留检测中的主导地位。毛细管电泳技术作为一种高效、快速的分离技术已得到广泛应用。文章就毛细管电泳技术在兽药和农药多残留检测分析中的应用做一介绍。     

纳豆菌制剂在动物养殖中的应用

纳豆菌是生产微生态制剂的理想菌株之一,现已作为绿色饲料添加剂广泛应用于饲料。本文主要就近年来纳豆菌制剂在动物养殖中的研究与应用成果作一概述,以期为畜牧生产提供参考。     

全混合日粮在生产实践中使用的条件与方法

全混合日粮(TMR)是现代奶牛场普遍采用的饲喂技术。本文就目前我国奶牛养殖场(户)使用TMR日粮应具备的条件及使用方法进行介绍。     

代谢组学及其在药物安全评价中的应用进展

阐述了代谢组学的概念、研究方法及其在药物毒理学和代谢研究中的应用,并对代谢组学技术在兽药安全评价中的应用前景以及在未来发展中面临的挑战进行了探讨。代谢组学是系统生物学的重要组成部分,已广泛应用于药物安全评价研究中。     

Application of Nanotechnology in Parasitology

Nanotechnology is the emerging development of the core information technology in the 1980s, and it has been widely used in life medicine, optoelectronics and other fields. Nanotechnology is effectively combined with parasitic disease reagents instrumentation, drug treatment, vaccine prevention and control, and has a comprehensive application in the nano-gold standard test strip test kit and equipment, nano-carrier targeted anthelmintic drugs, new nano-vaccine adjuvant of research and development, etc. It penetrates deeply into the medical field and is widely used in parasitology. With the starting point of the application of nanotechnology in parasitology, this paper focused on the pathogenic detection, anthelmintic drugs and vaccine adjuvants of parasitic diseases. The authors described the application of nano-technology, such as colloidal gold labeled immunoaffinity chromatography, microparticle material synthesis and biosensing, in the diagnosis and diagnosis of parasitic pathogens. The progress of new nano-insect repellent drug lipid carrier, chemical synthesis medicine and herbal medicine research and development had been discussed here, in addition to liposomes, polymer particles, and cytokines in vaccine adjuvants. This review could be expected as a reference for nanotechnology in in-depth research and better application in parasitology.     

纳米技术在寄生虫学中的应用

纳米技术是20世纪80年代新兴发展起来的核心信息技术,广泛应用于生命医学、光电化工等领域。纳米技术与寄生虫病的试剂仪器诊断、药物治疗及疫苗防控环节有机结合,全面应用于纳米金标检测试纸条、试剂盒和仪器设备、纳米载体靶向驱虫药物、新型纳米疫苗佐剂的研发制备等方面,深入渗透到医学领域并广泛应用到寄生虫学中。作者着眼于当前纳米技术在寄生虫学中的应用,重点阐述了其在寄生虫病的检测诊断、驱虫药物和疫苗佐剂中的应用情况,包括胶体金标记免疫亲和层析、微粒材料合成、生物传感等纳米技术在寄生虫病检测诊断中的应用,总结了新型纳米驱虫药物脂质载体、化学合成药、草本中药研发的进展,并对疫苗佐剂研发中的热点,如纳米脂质体、聚合物颗粒、细胞因子的相关进展进行了概述。本文旨在为纳米技术在寄生虫学中的深入应用和研究提供参考。