犬的现代繁殖技术

综述讨论了国内外犬的现代繁殖技术——人工辅助生育(ART)研究的各个方面,包括:人工授精(AI)、卵细胞的体外培养(IVC)和体外受精(IVF),胚胎移植(ET)、产前基因诊断(PGD)和克隆(Cloning)等一系列技术问题,以及犬繁殖技术研究方面目前存在的问题及应用前景。     

Exercise physiology. An overview

Through the study of equine exercise physiology, one can learn more about what happens to the body of the performance horse during all forms of exercise. Better understanding of skeletal, joint, tendon, and ligament adaptations to loading and stress may allow adjustments to be made in training techniques to reduce the incidence of injury. The information obtained from exercise research may also facilitate the investigation of questions such as the following: What makes one horse perform better than another? How can one bring out the optimal performance in each horse? How can one tell when a horse has arrived at its peak performance capability? What are the factors that actually limit performance?     

Computer applications. An overview

Applications are programs that are designed for specific tasks. They may be written by the ultimate user or by commercial programmers. Personally written software offers the benefit of a custom solution and adaptability to changing conditions but at a very high cost. Vendor software is cheaper, but more general in nature. It may be difficult for some practitioners to find commercial software that exactly duplicates their operation, and adaptations will add expense. Software maintenance may not be available or it may mean additional cost. Veterinarians can profit from practice management packages, computer-aided diagnostics, educational software, and other programs. Computers must solve the users' problems or they are worthless. With appropriate applications, they represent one of the most cost-effective instruments in the practice.     

Fracture complications. An overview

No surgical procedure is free of complications. Determining the reason that a complication of a fracture repair occurred and developing a treatment plan are important if the objectives of fracture treatment are to be met. It is also necessary to deal with owners, and, sometimes, other veterinarians in meeting these objectives.     

Diagnosis of canine monocytotropic ehrlichiosis (Ehrlichia canis): An overview

Canine monocytotropic ehrlichiosis (CME), caused by the rickettsia Ehrlichia canis, an important canine disease with a worldwide distribution. Diagnosis of the disease can be challenging due to its different phases and multiple clinical manifestations. CME should be suspected when a compatible history (living in or traveling to an endemic region, previous tick exposure), typical clinical signs and characteristic hematological and biochemical abnormalities are present. Traditional diagnostic techniques including hematology, cytology, serology and isolation are valuable diagnostic tools for CME, however a definitive diagnosis of E. canis infection requires molecular techniques. This article reviews the current literature covering the diagnosis of infection caused by E. canis.     

Equine heart disease. An overview

The clinician must appreciate unique aspects of equine cardiovascular physiology in order to distinguish normal variation from a pathophysiologic state. Cardiovascular problems in the horse include auscultation of cardiac murmurs, identification of cardiac arrhythmias, and recognition of congestive heart failure. A cardiac data base including history, general and cardiovascular examination, and resting and postexercise electrocardiogram are necessary to evaluate most horses for significant heart disease. Additional studies, such as echocardiography and cardiac catheterization, are useful in selected cases. Because some types of heart disease are amendable by therapy, an accurate diagnosis is needed to direct treatment and offer a realistic prognosis.     

Ghrelin研究进展

Ghrelin是1999年发现的28肽,为生长激素促分泌素受体天然的内源性配体。由下丘脑、垂体和多种组织产生,其受体(GHS-R1a和GHS-R1b)在体内广泛分布。具有调节生长激素分泌、摄食、能量代谢、神经内分泌、记忆、睡眠、胃肠功能等多种生物学作用。     

An overview of hemostasis

The normal hemostatic system is complex yet exquisitely well regulated. Interrelationships exist between responses of the vasculature, circulating platelets, coagulation proteins, and fibrinolytic mechanism. These relationships serve to limit blood loss, preserve tissue perfusion, and stimulate local repair processes. Natural inhibitors of coagulation and fibrinolysis modulate these systems to prevent uncontrolled thrombosis or hemorrhage following pathologic stimuli. Vascular endothelial cells play an important role in the maintenance of a thromboresistant luminal interface with circulating cells and proteins. Normal hemostasis also requires the synthetic, metabolic, and repair processes of the vascular endothelium. The initial vascular response to injury produces brief vasoconstriction and exposes subendothelial substances that attract circulating platelets and activate coagulation proteins. Platelets respond by adherence and aggregation at the site of injury, with subsequent release of substances that mitigate blood loss. Platelet adherence to collagen requires von Willebrand's factor, fibrinogen, fibronectin, and specific glycoprotein receptors on platelet surfaces. Platelet-to-platelet interactions (aggregation) recruit additional platelets to the primary hemostatic plug. Aggregation requires fibrinogen, energy, and calcium. Release of ADP, serotonin, and the contents of intracellular granules as well as generation of prostaglandins prepares platelet surfaces for reactions with the coagulation proteins. Activation of the intrinsic or extrinsic coagulation pathway, or of both, causes formation of fibrin from fibrinogen by means of an elaborate and intricate system that also entraps platelets and activated coagulation proteins. The intrinsic system is activated by the contact of factor XII with a negatively charged surface, most likely collagen. Through a series of reactions with prekallikrein, HMWK, and factors XI, IX, and VIII, the common coagulation pathway is propagated. The extrinsic, or tissue factor, system stimulates both the common pathway and factor IX the intrinsic pathway. Discovery of this stimulation of the intrinsic pathway by factor VII in the extrinsic pathway has stimulated reassessment of the biologic importance of the extrinsic system. The common pathway includes factors X and V and causes thrombin to convert fibrinogen to fibrin. Calcium and platelet phospholipids are substances that have important roles in steps in the coagulation scheme. Once fibrin is formed, factor XIII interacts with the substance, providing a stabilizing effect.(ABSTRACT TRUNCATED AT 400 WORDS)     

生殖激素在调控犬猫生殖中的作用

犬猫作为伴侣动物和人类医学的实验模型,其生殖激素的研究和应用得以长足的发展.近几年来,城市中饲养和流浪的犬猫数量大幅增长所突现的生育问题,有待研究解决,本文就此问题作一探讨.     

朊病毒研究进展

朊病毒 (Prion)是一类能引起人和动物的亚急性海绵样脑病的病原因子 ,它的化学本质是一种蛋白质侵染颗粒 ,具有不同于病毒的生物学性质与理化性质。细胞型朊病毒蛋白 (PrPC)经过折叠可转变为致病型朊病毒蛋白 (PrPSC)。目前人和大多数动物的PrP基因序列已经被测定 ,这也为朊病毒的研究提供了重要的信息。酵母朊病毒的研究进一步证实了朊病毒仅由蛋白质组成的假说     

牛结核病

牛结核病是牛分支杆菌引起的人畜共患传染病, 全球每年因结核病而死亡的人数是其他传染病的死亡人数之和。除了人和牛外, 还有很多动物对牛分支杆菌敏感, 如一些哺乳动物和禽类。家养牛被认为是牛分支杆菌的宿主, 但很多野生动物是贮存宿主。为了控制牛结核, 需要作到预防、检疫、根除、治疗。     

An overview of swine influenza

Swine influenza is a highly infectious viral disease of pigs, causing considerable economic impact. The causative agent is known as a type A orthomyxovirus with a segmented RNA genome. Influenza type A virus is a highly contagious pathogen among a limited number of birds and mammals. The objective of this review is to summarize the current knowledge in swine influenza infection in pigs with emphasizing on epidemiology, pathogenesis, diagnostic techniques and control measures.     

Reproductive physiology of the nonpregnant mare. An overview and update

This article reviews the reproductive events in the nonpregnant mare with emphasis on recent advances. The discussion is restricted to the salient features of puberty (prenatal and prepubertal events), seasonality (gonadotropins, photoperiod, and other modifying factors), and the estrous cycle (hormones, estrus, diestrus, and the control of cyclicity) in the nonpregnant mare.     

Kisspeptin as a master player in the central control of reproduction in mammals: An overview of kisspeptin research in domestic animals

The hypothalamo‐pituitary‐gonadal (HPG) axis is the regulatory system for reproduction in mammals. Because secretion of gonadotropin‐releasing hormone (GnRH) into the portal vessels is the final step at which the brain controls gonadal activities, the GnRH neuronal system had been thought to be central to the HPG axis. A newly discovered neural peptide, kisspeptin, has opened a new era in reproductive neuroendocrinology. As shown in a variety of mammals, kisspeptin is a potent endogenous secretagogue of GnRH, and the kisspeptin neuronal system governs both the pulsatile GnRH secretion that drives folliculogenesis, spermatogenesis and steroidogenesis, and the GnRH surge that triggers ovulation in females. The kisspeptin neuronal system is therefore considered a master player in the central control of mammalian reproduction, and kisspeptin and related substances could therefore be valuable for the development of novel strategies for the management of fertility in farm animals. To this end, the present review aimed to summarize the current research on kisspeptin signaling with a focus on domestic animals such as sheep, goats, cattle, pigs and horses.     

An overview of transmissible spongiform encephalopathies

Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders of humans and animals associated with an accumulation of abnormal isoforms of prion protein (PrP) in nerve cells. The pathogenesis of TSEs involves conformational conversions of normal cellular PrP (PrP(c)) to abnormal isoforms of PrP (PrP(Sc)). While the protein-only hypothesis has been widely accepted as a causal mechanism of prion diseases, evidence from more recent research suggests a possible involvement of other cellular component(s) or as yet undefined infectious agent(s) in PrP pathogenesis. Although the underlying mechanisms of PrP strain variation and the determinants of interspecies transmissibility have not been fully elucidated, biochemical and molecular findings indicate that bovine spongiform encephalopathy in cattle and new-variant Creutzfeldt-Jakob disease in humans are caused by indistinguishable etiological agent(s). Cumulative evidence suggests that there may be risks of humans acquiring TSEs via a variety of exposures to infected material. The development of highly precise ligands is warranted to detect and differentiate strains, allelic variants and infectious isoforms of these PrPs. This article describes the general features of TSEs and PrP, the current understanding of their pathogenesis, recent advances in prion disease diagnostics, and PrP inactivation.     

动物微生态制剂研究概述

1994年德国会议把微生态制剂定义修订为:"是含活菌和/或死菌包括其组分和产物的细菌制品,经口或其他粘膜途径投入,旨在改善粘膜表面微生物或酶的平衡,或者刺激特异性或非特异性免疫机制".     

An overview of positive pressure ventilation

Objective: The purpose of this article is to give the reader a brief overview of the indications for positive pressure ventilation (PPV). Data sources: Current human and veterinary literature. Summary: There are numerous indications for PPV in veterinary medicine. These include both pulmonary parenchymal disease and diseases that affect ventilation. When choosing PPV, a clinician must have a comprehensive understanding of the different ventilation mode options available and the physiologic effects of ventilation on the patient. Conclusions: PPV is becoming more widely used in veterinary medicine and is improving the survival of animals with hypoxemic and hypercapnic respiratory failure.