Perinatal hypoxia induces subsequent retinal degeneration in the offspring of ovoviviparous fish, Xiphophorous maculates

OBJECTIVE: This experiment evaluated the perinatal hypoxic effect on the retina of offspring of the ovoviviparous fish. ANIMAL STUDIED: The ovoviviparous fish Xiphophorous maculates was used for the experiment. PROCEDURE: The mothers were kept in a hypoxic environment of 3.5% oxygen for 6 h, starting 30 h before hatching. Subsequently, the retinae of the offspring were fixed, sectioned at 6 microm and evaluated microscopically from the age of 1 to 35 days. RESULTS: Degeneration of the outer nuclear layer of the retina was noted on the 3rd day and severe retinal degeneration was observed on the 35th day. Immunocytochemistry confirmed apoptosis by TUNEL reaction. There was no difference in neovascularization, as revealed by vascular endothelial growth factor, between controls (group 1) and hypoxic fish (group 2). CONCLUSIONS: Perinatal hypoxia could have long-lasting effects on the central nervous system in some species.     

Emerging therapeutic approaches for canine sarcomas: Pushing the boundaries beyond the conventional

Sarcomas represent a group of genomically chaotic, highly heterogenous tumours of mesenchymal origin with variable mutational load. Conventional therapy with surgery and radiation therapy is effective for managing small, low‐grade sarcomas and remains the standard therapeutic approach. For advanced, high‐grade, recurrent, or metastatic sarcomas, systemic chemotherapy provides minimal benefit, therefore, there is a drive to develop novel approaches. The discovery of “Coley's toxins” in the 19th century, and their use to stimulate the immune system supported the application of unconventional therapies for the treatment of sarcomas. While promising, this initial work was abandoned and treatment paradigm and disease course of sarcomas was largely unchanged for several decades. Exciting new therapies are currently changing treatment algorithms for advanced carcinomas and melanomas, and similar approaches are being applied to advance the field of sarcoma research. Recent discoveries in subtype‐specific cancer biology and the identification of distinct molecular targets have led to the development of promising targeted strategies with remarkable potential to change the landscape of sarcoma therapy in dogs. The purpose of this review article is to describe the current standard of care and limitations as well as emerging approaches for sarcoma therapy that span many of the most active paradigms in oncologic research, including immunotherapies, checkpoint inhibitors, and drugs capable of cellular metabolic reprogramming.     

Characterization of feline hereditary retinal dystrophies using clinical, functional, structural and molecular genetic studies

Only in recent years have specific mutations been elucidated for feline hereditary retinal dystrophies. Molecular genetic characterization of feline diseases has so far been a slow process but with a full genome sequence for the cat recently completed and the development of a feline single nucleotide polymorphism chip, the characterization of feline monogenic disorders will be significantly simplified. This review summarizes current knowledge with regard to specific hereditary retinal dystrophies in cats and gives an overview of how cats can be used as models in translational research.     

比格犬埃立克体病实验模型的建立

为犬埃立克体病的病理学、临床学、病原学的深入研究，我们用Beagle(比格犬）复制犬埃立克体病以建立犬埃立克体病实验模型。比格犬静脉接种E.platy和E.canis后，利用PCR和电镜技术确证感染成功。进一步的观察发现，接种后比格犬与最最感的德国牧羊犬自然感染埃立克体病的临床症关放病理学变化基本吻合。结果说明通过静脉接种病原成功建立了比格犬埃立克体病实验模型。     

The platelet factor-3 test for detection of canine antiplatelet antibody

Autoimmune thrombocytopenia can be diagnosed by demonstrating antiplatelet antibody in patient's serum using a platelet factor-3 test. A procedure was developed to conduct the platelet factor-3 test using a Fibrometer to record coagulation time. The procedure provides a more practical and consistent way of reading results than making visual observations. It is also simple enough for use as a laboratory method to evaluate thrombocytopenic patients. With this procedure, positive results were obtained for about one-third of the thrombocytopenic dogs examined so far.     

Sudden acquired retinal degeneration syndrome (SARDS) – a review and proposed strategies toward a better understanding of pathogenesis,early diagnosis,and therapy

Sudden acquired retinal degeneration syndrome (SARDS) is one of the leading causes of currently incurable canine vision loss diagnosed by veterinary ophthalmologists. The disease is characterized by acute onset of blindness due to loss of photoreceptor function, extinguished electroretinogram with an initially normal appearing ocular fundus, and mydriatic pupils which are slowly responsive to bright white light, unresponsive to red, but responsive to blue light stimulation. In addition to blindness, the majority of affected dogs also show systemic abnormalities suggestive of hyperadrenocorticism, such as polyphagia with resulting obesity, polyuria, polydipsia, and a subclinical hepatopathy. The pathogenesis of SARDS is unknown, but neuroendocrine and autoimmune mechanisms have been suggested. Therapies that target these disease pathways have been proposed to reverse or prevent further vision loss in SARDS‐affected dogs, but these treatments are controversial. In November 2014, the American College of Veterinary Ophthalmologists' Vision for Animals Foundation organized and funded a Think Tank to review the current knowledge and recently proposed ideas about disease mechanisms and treatment of SARDS. These panel discussions resulted in recommendations for future research strategies toward a better understanding of pathogenesis, early diagnosis, and potential therapy for this condition.     

Effects of hereditary retinal degeneration due to a CEP290 mutation on the feline pupillary light reflex

Objective To understand how progressive rod cone degeneration due to a mutation in CEP290 affects the pupillary light reflex (PLR) in domestic cats. Animals studied Domestic cats identified as either normal wildtype (WT; n = 6), or homozygous for the rdAc mutation in CEP290 and having early stage retinal degeneration (stage 2, S2; n = 4), or advanced retinal degeneration (S4; n = 6). Methods The effect of light on pupil size was measured over a series of 10‐s pulses of white and chromatic light in cats lightly sedated with medetomidine. Results In WT cats, the PLR was characterized by a pronounced initial constriction that rapidly re‐dilated during the stimulus (pupil escape), to a stable or sustained constriction. There was then a marked constriction at stimulus offset. Each component of the PLR was retained in affected cats, but with progressively reduced irradiance sensitivity from early to advanced retinal disease. Conclusions The PLR of cats had multiple phases, with a remarkably high‐amplitude ‘paradoxical’ off‐constriction even in the absence of retinal disease. In rdAc cats, reduced irradiance sensitivity was consistent with progressive loss of rod and cone function. Based on previously characterized retinal pathology, this suggests the visual streak of the retina has a proportionally large contribution to PLR input. These findings support the hypothesis that the efficacy of planned therapeutic trials can be determined by careful evaluation of the PLR in cats.     

The use of the rapid osmotic fragility test as an additional test to diagnose canine immune-mediated haemolytic anaemia

Background

Diagnosing canine immune-mediated haemolytic anaemia (IMHA) is often challenging because all currently available tests have their limitations. Dogs with IMHA often have an increased erythrocyte osmotic fragility (OF), a characteristic that is sometimes used in the diagnosis of IMHA. Since the classic osmotic fragility test (COFT) is time-consuming and requires specialized equipment, an easy and less labour-intensive rapid osmotic fragility test (ROFT) has been used in some countries, but its diagnostic value has not yet been investigated.This study aimed to evaluate erythrocyte osmotic fragility in dogs with and without IMHA, to compare results of the classic (COFT) and rapid (ROFT) test and to assess the value of the ROFT as diagnostic test for canine IMHA.Nineteen dogs with IMHA (group 1a), 21 anaemic dogs without IMHA (group 1b), 8 dogs with microcytosis (group 2), 13 hyperlipemic dogs (group 3), 10 dogs with lymphoma (group 4), 8 dogs with an infection (group 5) and 13 healthy dogs (group 6) were included.In all dogs, blood smear examination, in-saline auto-agglutination test, Coombs’ test, COFT and ROFT were performed. In the COFT, OF5, OF50 and OF90 were defined as the NaCl concentrations at which respectively 5, 50 and 90% of erythrocytes were haemolysed.

Results

Compared with healthy dogs, OF5 and OF50 were significantly higher in group 1a (P < 0.001) and OF5 was significantly higher in group 3 (P = 0.0266). The ROFT was positive in 17 dogs with IMHA, 10 hyperlipemic dogs, one anaemic dog without IMHA and one healthy dog.

Conclusions

Osmotic fragility was increased in the majority of dogs with IMHA and in dogs with hyperlipidemia, but not in dogs with microcytosis, lymphoma or an infection. Although more detailed information was obtained about the osmotic fragility by using the COFT, the COFT and ROFT gave similar results. The ROFT does not require specialized equipment, is rapid and easy to perform and can be used easily in daily practice. Although, the ROFT cannot replace other diagnostic tests, it may be a valuable additional tool to diagnose canine IMHA.     

Effect of dasatinib in a xenograft mouse model of canine histiocytic sarcoma and in vitro expression status of its potential target EPHA2

Canine histiocytic sarcoma (HS) is an aggressive and highly metastatic tumor. Previously, the kinase inhibitor dasatinib was shown to have potent growth inhibitory activity against HS cells in vitro, possibly via targeting the EPHA2 receptor. Here, the in vivo effect of dasatinib in HS cells was investigated using a xenograft mouse model. Moreover, the expression status of EPHA2 was examined in six HS cell lines, ranging from insensitive to highly sensitive to dasatinib. In the HS xenograft mouse model, dasatinib significantly suppressed tumor growth, as illustrated by a decrease in mitotic and Ki67 indices and an increase in apoptotic index in tumor tissues. On Western blot analysis, EPHA2 was only weakly detected in all HS cell lines, regardless of sensitivity to dasatinib. Dasatinib likely results in the inhibition of xenograft tumor growth via a mechanism other than targeting EPHA2. The findings of this study suggest that dasatinib is a targeted therapy drug worthy of further exploration for the treatment of canine HS.     

Utilization of an enzyme heat stability test and erythrocyte glycolytic intermediate assays to assist in the diagnosis of canine pyruvate kinase deficiency

A macrocytic hypochromic anemia, with marked reliculocytosis and large numbers of circulating nucleated erythrocytes, was recognized in a 3 1/2-year-old male Beagle-cross dog. A presumptive diagnosis of erythrocyte pyruvate kinase (PK) deficiency was made, even though PK activity from the patient was within the range of activities measured for normal dogs, because the PK activity should have been several times normal in light of the large number of reticulocytes present. The PK activity in a hemolysate from the patient was heat-labile compared to activities in hemolysates from normal dogs, a finding consistent with results from a previous study of PK-deficient Basenji dogs. Seven phosphorylated glycolytic intermediates and 2,3-diphosphoglycerate were measured in protein-free extracts of erythrocytes from the patient. All were present in concentrations above that present in normal canine erythrocytes, further supporting the diagnosis of PK deficiency.     

自制貉源抗血清治疗犬瘟热病的研究

应用含有104.5TCID50/0.1 mL犬瘟热弱毒培养物4 mL免疫特种经济动物乌苏里貉,10 d后采集血液分离血清,病毒用200TCID50与等量连续倍比稀释的血清和经饱和硫酸铵粗提的免疫球蛋白做中和试验鉴定抗体的效价,并对上述2种抗体效价进行比较。结果表明,2917倍稀释全血清、2344倍稀释饱和硫酸铵粗提的免疫球蛋白能保护50%Vero细胞不出现CPE。临床应用全血清治疗24只患犬瘟热病的白貉,22只成活。由此说明可以应用狐貉等特种动物制备的抗血清治疗犬瘟热病。     

The use of delayed gadolinium enhanced magnetic resonance imaging of cartilage and T2 mapping to evaluate articular cartilage in the normal canine elbow

Commonly used diagnostic tools used to evaluate articular cartilage lack the sensitivity, specificity, and objectivity to measure early changes associated with osteoarthritis. Two techniques using magnetic resonance (MR) imaging have been developed to detect the biology of articular cartilage are delayed gadolinium-enhanced MR imaging of cartilage (dGEMRIC) and T2 mapping. Both techniques have been validated and are used to study the degenerative and adaptive nature of articular cartilage in people. The use of these techniques as a diagnostic tool in dogs has not been well described. We evaluated articular cartilage in the region of the medial coronoid process (MCP) of six healthy dogs free of detectable orthopedic disease using both MR imaging techniques. Histology and proteoglycan (PG) content of the MCP were used to confirm normal articular cartilage. All dogs had ground reaction forces consistent with normal function. Mean dGEMRIC index (T1 value) was 400 +/- 47 ms and mean T2 value was 56 +/- 8 ms. Intra- and interobserver variability was low. dGEMRIC and T2 values for normal cartilage in the elbow of the dog can be generated reproducibly using 3T MR imaging. Using these techniques as objective outcome measures for clinical studies in dogs with OA conditions should help delineate the efficacy of some disease interventions.     

The controversial histologic classification of canine subcutaneous whorling tumours: The path to perivascular wall tumours

Subcutaneous spindle cell tumours characterized by whorling growth patterns are common in dogs and are identified as a distinct entity. These tumours were misnamed as hemangiopericytomas (HPCs) because of some minor morphological parallels with their human counterparts. In veterinary medicine, the cell of origin of HPC has been under debate for a long time. Some authors have suggested a perivascular origin while others a perineural one. The evidence of the orientation of the neoplastic cells around the vessels and the expression of contractile proteins supported a perivascular origin while S100 expression and an inconsistent vascular connection supported a perineural origin. Despite the morphological similarities with peripheral nerve sheath tumours in humans, the perineural origin was supported mainly by the expression of markers with low specificity. On the contrary, the majority of studies have supported the perivascular origin of ‘old’ canine HPC. Since a variable degree of myoid‐pericytic differentiation was described, the term perivascular wall tumours (PWTs) were suggested to substitute HPC. Once the diagnostic criteria of PWTs were defined, the clinical behaviour and prognostic variables were investigated, demonstrating differences as compared with the group of canine soft tissue sarcomas (STSs) in general. PWTs are less aggressive, mostly locally invasive, and rarely metastasizing. Their behaviour seems to be less influenced by histological grade, suggesting that canine STSs are heterogeneous. The study of the biological behaviour of specific STS tumour types may be valuable in detecting differences which have passed unnoticed when STSs have been studied concomitantly.     

区分犬瘟热病毒Asia-Ⅰ型野毒株及疫苗株的AS-PCR方法

犬瘟热是一种接触性传染病,可侵害免疫系统、呼吸系统、消化系统,甚至神经系统,导致全身性的病理变化,对宠物犬、毛皮动物等存在巨大威胁。目前常用的胶体金检测法不能有效区分疫苗免疫与动物自然感染。为建立一种高效准确的鉴别犬瘟热病毒野毒株和疫苗株的检测方法,本试验对从武汉地区收集已确诊犬瘟热的6只犬分离得到的野毒株以及3株广泛使用的CDV疫苗株进行全基因组测序,从氨基酸水平和碱基水平比对分析后,确定H基因为AS-PCR引物设计的靶基因。通过对H基因进行分型,发现武汉地区流行的CDV均为Asia-Ⅰ型,而疫苗株Y2为America-I型,疫苗株Y1和Y3均为America-Ⅱ型。对比179株Asia-Ⅰ型（6株野毒株样品+173株GenBank Asia-Ⅰ型）与3株疫苗株的CDV-H基因序列,采用AS-PCR技术（3'端错配）设计出1对能有效区分犬瘟热Asia-Ⅰ型野毒株和疫苗株的特异性引物,上游引物序列为5'-TTAAATGATAATGACATAGTG-3',下游引物序列为5'-CCTGGCAAGGCAAGA-3'。结果显示该引物有较强的特异性,6株样品野毒株均可扩增出长894 bp的片段,疫苗株不能扩增,且野毒株的H基因上存在9个较为规律的碱基（氨基酸）变异位点,而疫苗株在第277位氨基酸上均为天冬酰胺,这些变异可能导致N-糖基化位点的增加,从而对犬瘟热病毒疫苗株的毒力产生影响。本研究建立的AS-PCR方法能有效区分犬瘟热疫苗和Asia-Ⅰ型野毒株。