Ammonia Metabolism and the Urea Cycle: Function and Clinical Implications

Disposal of waste products accumulated during metabolic processes is integral to the health of any living organism. Disposal of excess nitrogen and ammonia is no exception. Although nitrogen is essential for growth and maintenance in animals, an excess of some nitrogenous compounds can quickly lead to toxicity and death. Because of the correlation between ammonia accumulation and clinical disease, it is important for veterinary clinicians to understand the physiological mechanisms used to dispose of nitrogen and ammonia. Therefore, the purposes of this article are to review ammonia metabolism, the urea cycle, and the clinical implications of urea cycle dysfunction in diseases of companion animals.     

The physiology of stress and its relationship to mechanisms of disease and therapeutics

Although stress reactions are organized to protect the homeostatic state of animals, they contain elements that may either enhance or diminish susceptibility to disease processes; in many instances, however, stress reactions themselves may induce pathologic change. It is important, therefore, that the veterinary clinician recognize the elements of a stress reaction and understand the mechanisms of disease with which they interact. This article provides a classification of stress stimuli that can be applied when considering interactions between stress reactions and disease processes.     

The biology, pathophysiology and control of eicosanoids in inflammation

The involvement in inflammatory conditions of those cyclo-oxygenase and lipoxygenase derivatives of arachidonic acid (5,8,11,14-eicosatetraenoic acid), which are known as the eicosanoids, is reviewed in the light of recent studies. Although it is now generally recognized that cyclo-oxygenase products are fundamental to the inflammatory process as chemical mediators, and that inhibition of the cyclo-oxygenase enzyme pathway explains the mode of action of most non-steroidal anti-inflammatory drugs (NSAIDs) commonly prescribed in veterinary practice, evidence for the involvement of lipoxygenase products of arachidonate metabolism in inflammation is increasing. The leukotrienes (LTs) are 5-lipoxygenase-derived eicosanoids which have been shown to be leucotactic and involved in anaphylactic and hypersensitivity reactions. Leucocytes, drawn to sites of injury by chemotaxis, themselves liberate pro-inflammatory eicosanoids which perpetuate the response and may aggravate the clinical condition. At therapeutic dose rates, most NSAIDs have no effect on the biosynthesis of LTs, whereas corticosteroids, by inhibiting the release of arachidonic acid, may prevent the formation of both cyclo-oxygenase and lipoxygenase products. However, because of the undesirable side-effects of steroids, the clinical use of these agents in treating inflammatory conditions is sometimes limited. Novel non-steroid inhibitors of cyclo-oxygenase and lipoxygenase enzyme pathways could offer more effective and safer control of inflammation in animals.     

Use of complementary veterinary medicine in the geriatric horse.

The use of complementary and alternative veterinary medicine continues to grow within the veterinary community. As more clients seek out complementary and alternative medicine for their own health care, they begin to seek out these forms of therapy for their animals. For the equine practitioner, this includes those clients with geriatric animals. It is hoped that this article provides some insight into what conditions may be helped with CVM (complementary veterinary medicine) and when an equine practitioner may want to consider CVM as a form of therapy for the geriatric horse.     

The role of nutrients in modulating disease

The role of nutrition in the management of diseases has often centred on correcting apparent nutrient deficiencies or meeting estimated nutritional requirements of patients. Nutrition has traditionally been considered a supportive measure akin to fluid therapy and rarely it has been considered a primary means of ameliorating diseases. Recently, however, further understanding of the underlying mechanisms of various disease processes and how certain nutrients possess pharmacological properties have fuelled an interest in exploring how nutritional therapies themselves could modify the behaviour of various conditions. Nutrients such as omega-3 fatty acids, antioxidants and certain amino acids such as arginine and glutamine have all been demonstrated to have at least the potential to modulate diseases. Developments in the area of critical care nutrition have been particularly exciting as nutritional therapies utilising a combination of approaches have been shown to positively impact outcome beyond simply proving substrate for synthesis and energy. Application of certain nutrients for the modulation of diseases in veterinary patients is still in early stages, but apparent successes have already been demonstrated, and future studies are warranted to establish optimal approaches. This review describes the rationale of many of these approaches and discusses findings both in human beings and in animals, which may guide future therapy.     

Cannabinoids CB2 Receptors,One New Promising Drug Target for Chronic and Degenerative Pain Conditions in Equine Veterinary Patients

Osteoarticular equine disease is a common cause of malady; in general, its therapy is supported on steroids and nonsteroidal anti-inflammatories. Nevertheless, many side effects may develop when these drugs are administered. Nowadays, the use of new alternatives for this pathology attention is demanded; in that sense, cannabinoid CB2 agonists may represent a novel alternative. Cannabinoid belongs to a group of molecules known by their psychoactive properties; they are synthetized by the Cannabis sativa plant, better known as marijuana. The aim of this study was to contribute to understand the pharmacology of cannabinoid CB2 receptors and its potential utilization on equine veterinary patients with a chronic degenerative painful condition. In animals, two main receptors for cannabinoids are recognized, the cannabinoid receptor type 1 and the cannabinoid receptor type 2. Once they are activated, both receptors exert a wide range of physiological responses, as nociception modulation. Recently, it has been proposed the use of synthetic cannabinoid type 2 receptor agonists; those receptors looks to confer antinociceptive properties but without the undesired psychoactive side effects; for that reason, veterinary patients, whit chronical degenerative diseases as osteoarthritis may alleviate one of the most common symptom, the pain, which in some cases for several reasons, as patient individualities, or side effects produced for more conventional treatments cannot be attended in the best way.     

Potential for control of oxidative injury by administration of antioxidants in veterinary medicine

Cellular metabolism results in the production of reactive oxygen species otherwise known as free radicals. When not kept under control these molecules cause damage to various compartments in cells. These molecules are kept in check with antioxidant compounds that can be endogenous to cells or are present in the diet. When this balance is in the favor of reactive oxygen species then the physiological condition is considered to be in oxidative stress, which can lead to oxidative injury in various tissues. There has been a lot of interest in the effects of free radicals and the various degenerative diseases. This interest has lead to theories such as the free radical theory of aging, which states that aging is the accumulation of damage over time that leads to degenerative diseases. This has lead to a host of interest in the interaction of oxidative damage and certain disease states and how antioxidants may be beneficial in helping to modulate various disease states. In order to understand the potential for controlling oxidative injury in veterinary medicine, one needs to understand the cellular processes that reactive oxygen species and antioxidant compounds play in the body. It is usually thought that oxidative injury results in oxidative damage to the lipid, protein, and DNA components of cells. This damage results in alterations in cellular function. Various antioxidant compounds function to scavenge free radicals before they are able to damage the various cellular components     

Abdominal ultrasonography in small animals: Examination of the liver, spleen and pancreas

Ultrasonography is an important diagnostic technique in veterinary medicine. It may be used to examine most structures in the small animal ahdomen, providing a rapid, non-invasive means of supplementing information obtained by physical examination and radiography. Limitations of ultrasonography include the non-specific nature of many observed abnormalities, which prevents a specific diagnosis, and the difficulty of identifying certain normal organs such as the pancreas. This paper reviews ultrasonography of the liver, spleen and pancreas, and ultrasound-guided biopsy in small animals, and indicates areas of potential future development.     

The animal's microbiome and cancer: A translational perspective

Cancer is a substantial global health problem both in humans and animals with a consistent increase in mortality and incidence rate. The commensal microbiota has been involved in the regulation of several physiological and pathological processes, both within the gastrointestinal system and at distant tissue locations. Cancer is not an exception, and different aspects of the microbiome have been described to have anti- or pro-tumour effects. Using new techniques, for example high-throughput DNA sequencing, microbial populations of the human body have been largely described and, in the last years, studies more focused on companions' animals have emerged. In general, the recent investigations of faecal microbial phylogeny and functional capacity of the canine and feline gut have shown similarities with human gut. In this translational study we will review and summarize the relation between the microbiota and cancer, in humans and companion animals, and compare their resemblance in the type of neoplasms already studied in veterinary medicine: multicentric and intestinal lymphoma, colorectal tumours, nasal neoplasia and mast cell tumours. In the context of One Health, microbiota and microbiome integrative studies may contribute to the understanding of the tumourigenesis process, besides offering an opportunity to develop new diagnostics and therapeutic biomarkers both for veterinary and human oncology.     

Brachyury基因的研究进展

Brachyury基因是T-box基因家族编码的一种转录因子,该基因已经在包括腔肠动物在内的许多动物中发现。Brachyury基因在调控生物体胚胎发育、细胞迁移等许多方面扮演着重要角色,其功能还涉及胚胎发育过程中器官形成等生理过程。研究发现,人类肿瘤疾病、动物脊索发育、动物尾型的畸形生长都与Brachyury基因有直接联系。主要就Brachyury基因与肿瘤疾病、动物短尾性状形成的研究进展进行综述,以期为相关研究提供参考。     

Application of Campylobacter molecular classification and typing techniques in veterinary medicine: old-established methods and new perspectives

In this review the application and usefulness of Campylobacter genotypical classification and typing in veterinary medicine will be discussed.While there is a large area of overlapping applications between the veterinary and the medical field, several differences exist, as the spectrum of veterinary pathogens is different from the human and contaminated food of healthy animal origin may cause disease in man. In general, genotyping in the veterinary field can be applied in three different areas: (a) purely diagnostic purposes for classification of Campylobacter species and subspecies, (b) typing methods useful for monitoring or surveillance of animals as well as food products of animal origin, and (c) typing methods that can be applied during outbreaks and for source tracing. In addition, typing methods applied in areas (b) and (c) should be distinguished in regard to local short-term and global long-term epidemiology, respectively. While a whole plethora of discriminative typing methods are available, classification tools of certain species and subspecies are still missing. Perspectively, as the genomes of many relevant Campylobacter species have now been sequenced, this will help to identify several species specific loci, the products of which should be available to develop easy and fast applicable diagnostic tools. Global cooperation, sharing of strains and databases should close the currently existing gaps in Campylobacter identification tools.     

自噬对奶牛乳腺发育和功能影响的研究进展

自噬是细胞降解自身受损细胞器和长寿命蛋白的过程,有助于在饥饿、应激等情况下保护细胞存活。奶牛乳腺组织在青春期和妊娠期经历生长发育,在泌乳后期和干奶期进行退化再生,自噬在这2个过程中均发挥重要作用,既可以保护乳腺上皮细胞存活,又可以促使细胞发生程序性死亡。自噬也与机体中许多生理、病理过程相互作用,并受体内外多种因素的影响。本文就自噬的过程、自噬在奶牛乳腺组织生长发育和退化再生过程中发挥的作用及其影响因素进行综述,以期为通过调控自噬改善奶牛生产性能提供理论依据。     

Enantioselective behaviour of drugs used in domestic animals: a review

The chirality of drugs, with particular reference to agents used in veterinary medicine, is reviewed. Basic concepts of chirality and aspects of the methodology for the separation of enantiomers are considered. Chiral compounds are in common use in animals and their pharmacological actions and side-effects (pharmacodynamics) and absorption into and fate within the body (pharmacokinetics) are of fundamental importance; pharmacodynamic and pharmacokinetic properties of enantiomeric pairs commonly differ and this has major implications for their effective and safe therapeutic use. As examples of the particular significance of chirality in veterinary medicine, the following drug classes are reviewed; benzimidazole anthelmintics, cloprostenol, verapamil, ketamine, halogenated hydrocarbon anaesthetics and 2-arylpropionic acid anti-inflammatory drugs. The implications of chirality for drug product development and approval by registration authorities are discussed.     

Tuareg ethnoveterinary treatments of camel diseases in Agadez area (Niger)

For generations, nomadic herders have been learning to manage herd health, particularly in dromedaries because of their great value. Owing to the unavailability of veterinary services, camel herders in remote areas have been developing their own pharmacopoeia and veterinary techniques. The bleeding of sick animals is a common treatment, as Tuareg herders believe that ‘tainted blood’ (izni) is the cause of many conditions. Several surgical techniques are also used, such as excision of calcified sublingual cord. The remedies mentioned in this survey are derived from Maerua crassifolia, Boscia senegalensis, Acacia raddiana, Cucumis prophetarum, Calotropis procera, Ricinus communis, Citrullus colocynthis, green tea, millet, tobacco and onions. Artificial elements are also used for treatment of animals: Powders collected from batteries, various haircare or skincare creams, crushed glass, insecticides or motor oil belong to their pharmacopoeia. This broadmindedness allows the introduction of modern veterinary medicine. Factors such as the lack of real production objectives constitute limits to this progress, however.     

A new era in veterinary immunology

The importance of the creation of a new international journal of "Veterinary Immunology and Immunopathology" is apparent following the emergence of veterinary immunology as an identifiable discipline and the vital part played by investigations of animal models of immunological diseases of man. The journal will contain papers on basic immunology of domestic animals and on the many disease processes that result in domestic and laboratory animals from immunologic defects. It should thus have a wide appeal to workers in all immunologically related disciplines. Papers will be refereed by members of an international editorial advisory board.     

Large-animal handling at the Colorado State University College of Veterinary Medicine

Colleges of veterinary medicine face many challenges in teaching the handling of large animals. It is imperative that students be taught how to manage large animals, however, not only for their safety but for that of their clients and of the animals themselves. Confident, safe, and efficient handling can improve job satisfaction and may encourage students to enter large-animal practice. There is wide variation in the large-animal-handling components of US veterinary curricula.     

Meticillin-resistant Staphylococcus pseudintermedius: clinical challenge and treatment options

Meticillin-resistant Staphylococcus pseudintermedius (MRSP) has emerged as a major therapeutic challenge for small animal veterinarians over the past 10 years and continues to spread worryingly in many countries. This review focuses on the clinical aspects of MRSP infections seen in patients with skin disease and on currently available treatment options. In addition, it discusses the implications for in-contact people, other animals and the environment, because infection control strategies are likely to have a significant impact on treatment success and prevention of spread. There is currently no indication that MRSP is more virulent than meticillin-susceptible S. pseudintermedius, and reported infections have mostly been treated successfully, although possibly with a longer time to resolution than infections with more susceptible S. pseudintermedius. However, in vitro testing of MRSP isolates indicates resistance to most or all antibacterial agents licensed for use in pets. Based on susceptibility results, the most useful systemic antimicrobials may include chloramphenicol, rifampicin, amikacin, clindamycin and/or minocycline. Adverse effects of some of these medications may limit their usefulness. While in vitro susceptibility to vancomycin and linezolid is reported by some laboratories, use of these drugs in animals is strongly discouraged because of ethical considerations. Aggressive topical therapy has been effective as the only treatment in certain cases. Awareness, continued research and comprehensive management of infections are required by veterinary practitioners not only to help treat infected animals but also to limit the spread and prevent the establishment of this highly drug-resistant and zoonotic pathogen in veterinary facilities and in the community.     

Antinuclear antibodies: presence and specificity in autoimmune connective tissue disease in the dog.

Autoimmune connective tissue disease in both animals and humans present as multi-systemic disorders. Clinical signs referable to joints, musculoskeletal system and Dermatopathies are present. Autoantibody production is a regular feature of systemic autoimmune disease and these antibodies have diagnostic value in both human and veterinary medicine. In this study, we demonstrate that many of the commonly used diagnostic techniques developed for use with human patients may also be adapted for use in dogs. However, in some instances, 'canine specific' autoantibodies, distinct from analogous human antibodies may be detected in sera from dogs with a diagnosis of autoimmune disease. This finding indicates that dogs may develop 'dog-specific' autoimmune connective tissue disease.