Influence of cycle stage, age and endometrial biopsy score on oxytocin receptor distribution and gene expression in the cervix and uterus of non-pregnant mares.

Persistent breeding-induced endometritis (PBIE) or delayed uterine clearance (DUC) are major causes of mare subfertility. Oxytocin and its receptor are thought to play significant roles in the pathogenesis of DUC but the specific roles of oxytocin receptor (OR) distribution and gene expression remain undefined. In this study both OR distribution and gene expression in the endometrium, myometrium and cervix during both luteal and non-luteal phases in non-pregnant mares (n = 27) of differing age (young: 2-9 years, n = 17; old: > 10 years, n = 10) and endometrial biopsy score were described using immunohistochemistry (IHC) and quantitative reverse-transcription polymerase chain reaction (RT-qPCR), respectively. Immunohistochemistry showed a similar pattern of OR distribution in uterus and cervix, with the exception of the glandular epithelium, absent in the cervix. Uterine ORs were localized in endometrial luminal and glandular epithelia, transmural vascular endothelium, sub-epithelial and peri-glandular stromal cells and myometrial smooth muscle cells. The OR labeling intensity was consistently greatest in the vascular endothelium. Real-time qPCR showed a higher OR gene expression in myometrium compared to cervix (P = 0.001) and endometrium (P = 0.009). There was no difference in OR gene expression between cervix and endometrium (P = 1.0). Oxytocin receptor gene expression was significantly higher during the non-luteal phase in both combined uterine tissues (endometrium and myometrium) and myometrium. Oxytocin receptor distribution and gene expression were not influenced by a mare's age or endometrial biopsy score. As endometrial biopsy score and mare age were not predictors of OR gene expression, deficient OR gene expression is unlikely to be associated with DUC.

Genotyping and comparative pathology of Spirocerca in black-backed jackals (Canis mesomelas) in South Africa.

BACKGROUND: The pathology of spirocercosis, a disease caused by the infestation of carnivores with the nematode Spirocerca lupi, has been extensively described in domestic dogs and coyotes. However, it has not been described in wild carnivores in South Africa. The aim of this study was to evaluate whether black-backed jackals are a host for Spirocerca species and to provide a detailed description of the associated pathology. Jackals were also stratified according to age and the Spirocerca species recovered were characterized using molecular techniques. METHODS: Standard necropsies were performed on routinely culled jackals from three of the nine provinces of South Africa during the period June 2012 to February 2013. Jackals were screened for the presence of pathognomonic Spirocerca-induced lesions and for evidence of aberrant migration. Relevant samples were submitted for histopathology and collected larvae were genotyped at nine microsatellite loci. RESULTS: Spirocerca lupi-associated aortic lesions were found in 16 of 93 (17%) black-backed jackals. Of these, four (25%) were associated with S. lupi larvae. Genotyping of the larvae revealed amplification of all nine loci that amplified dog-derived S. lupi, with the same level of polymorphism in the allele size ranges. Only 1 of 93 jackals had an esophageal nodule with concurrent S. lupi-induced aortic aneurysms. The single esophageal nodule found did not contain adult nematodes, nor did it communicate with the esophageal lumen. None of the jackals that were examined had macroscopically evident spondylitis, which is frequently reported in the dog. Histopathology of the S. lupi-induced aortic lesions in the jackal revealed replacement of elastic and smooth muscle fibers by fibrous connective tissue. In cases where inflammation was present, the inflammatory infiltrate consisted predominantly of eosinophils. The single esophageal nodule histologically resembled the early inflammatory nodule described in dogs and consisted of fibrous connective tissue, multifocal accumulation of lymphocytes, plasma cells and rare hemosiderin-laden macrophages. CONCLUSIONS: These lesions suggest that the life cycle of S. lupi may not or only rarely be completed in jackals. A possible explanation might be that jackals are relatively resistant to developing significant pathology associated with S. lupi-infection. However, before any conclusions can be drawn, many more jackals, including those that die naturally will have to be investigated for evidence of S. lupi infection.

Immunohistochemical characterization of lymphocyte and myeloid cell infiltrates in spirocercosis-induced oesophageal nodules.

Spirocerca lupi is a nematode that infects the dog's oesophagus and promotes the formation of an inflammatory fibroblastic nodule that progresses to sarcoma in approximately 25% of cases. Spirocercosis-associated oesophageal sarcoma is an excellent and under-utilized spontaneous model of parasite-associated malignancy. The inflammatory infiltrate of paraffin-embedded, non-neoplastic oesophageal nodules (n = 46), neoplastic nodules (n = 25) and normal oesophagus (n = 14) was examined by immunohistochemistry using MAC387 (myeloid cells), CD3 (T cells), Pax5 (B cells) and FoxP3 (T regulatory cells) antibodies. Myeloid cells predominated in 70% of nodules, in pockets around the worms' migratory tracts and in necro-ulcerative areas in neoplastic cases. T cells predominated in 23% of cases with a focal or diffuse distribution, in the nodule periphery. No significant differences were observed between neoplastic and non-neoplastic stages. FoxP3+ cells were observed in low numbers, not significantly different from the controls. The inflammation in spirocercosis is characterized by pockets of pus surrounded by organized lymphoid foci. There was no evidence of a local accumulation of FoxP3+ cells, unlike many previous studies that have reported an increase in FoxP3+ T cells in both malignancies and parasite infections. The triggering factor(s) driving the malignant transformation of the spirocercosis-associated chronic inflammatory nodule warrants further investigation.

Tissue tropism of African horsesickness virus in the chicken embryo demonstrated with the avidin-biotin complex immunoperoxidase method.

In horses, African horsesickness virus (AHSV) exhibits marked tropism for certain microvascular endothelia and components of the mononuclear phagocyte system. In this study, the tropism of a field isolate of AHSV serotype 5 was studied in 24 chicken embryos. Histopathology on embryonic tissues harvested with 12 hour intervals revealed progressive changes associated with endothelial damage. Immunolabeling demonstrated viral antigens in the microvascular endothelium of the spleen, lungs, and the mesenchymal connective tissue at the base of the neck, from 24 hours post inoculation. Subsequently, specific immunolabeling increased steadily in endothelia of these and other tissues such as skeletal and cardiac muscle, gastrointestinal smooth muscle, mesonephric glomeruli, liver, subcutis and feathers. Positive immunolabeling was also occasionally observed in circulating mononuclear cells and in Kupffer cells in the liver. It was concluded, that this isolate of AHSV displayed similar tissue tropism in the chicken embryo as in the horse.

Tissue and cell tropism of African horse sickness virus demonstrated by immunoperoxidase labeling in natural and experimental infection in horses in South Africa.

Tissues from 196 experimental and confirmed natural cases of African horse sickness (all 9 serotypes) were examined with a standardized and validated immunohistochemical assay for detection of the causative virus. The study confirmed that heart and lung are the main target tissues for African horse sickness virus (across all serotypes), followed closely by spleen. It also indicated that microvascular endothelial cells and monocyte-macrophages are the main target cells for virus replication. The importance of monocytes as target cells was emphasized, with relatively few tissue macrophages containing antigen in the lung and spleen, respectively. The results were largely in agreement with those of previous studies, but the large number of cases examined permitted more precise description of the location and distribution of antigen in different tissues. Comparison with descriptions of tissue and cell tropism of other orbiviruses indicated similarity with African horse sickness. Immunohistochemistry was shown to be a useful and consistent technique for demonstrating target cells, but the difficulty of identifying cell types-in particular, different types of monocyte-macrophages-is a limitation.

Infiltrative angiolipoma of the parotid salivary gland in a dog.

Solitary benign angiolipoma and infiltrative angiolipoma are rare tumours in dogs. Angiolipomata can be distinguished histologically from lipomata by the large number of tightly packed blood vessels seen between the adipocytes with multiple fibrin thrombi occupying some of the vessels' lumens. The dog presented with a solitary slow-growing mass in the cervical region. Histopathology revealed multifocal to coalescing single or clusters of blood-filled vessels lined by flattened endothelial cells with narrow, elongated, basophilic nuclei. These regions were embedded in adipose tissue with multifocal areas of intervascular remnants of differentiated serous salivary glandular tissue with multifocal small ducts. Fibrin thrombi occupied a few of the vessel lumens. A histological diagnosis of infiltrative angiolipoma was made. On computed tomography, the mass was bilobed with a suspected primary component involving the right parotid gland which was grossly enlarged. The mass had a slightly hypoattenuating mottled to lobulated appearance with a few hyperattenuating mineralised specks throughout. Hounsfield units of the mass ranged between 40 and 45, which was less than the 60-65 of the contralateral salivary glands and cranial musculature. Post contrast images showed no contrast enhancement of 90% of the mass with only a band of peripheral contrast uptake of the affected lateral lobe.

Proposed histological progression of the Spirocerca lupi-induced oesophageal lesion in dogs.

This study aims to outline the histological progression of the Spirocerca lupi nodule from infection to neoplastic transformation. Sixty-two spirocercosis-induced nodules, 42 non-neoplastic and 20 neoplastic, were stained with HE. Ten non-overlapping high power fields per nodule were examined and non-neoplastic and neoplastic nodules were compared. Inflammation was scored 0-3 and revealed a score of 1.91+/-0.52 in the non-neoplastic and 0.97+/-0.5 in the neoplastic cases (p<0.01). In most non-neoplastic cases the inflammatory infiltrate was lymphoplasmacytic and in the neoplastic cases neutrophils predominated. Necrosis was scored 0-3 and revealed a score of 0.88+/-0.41 in the non-neoplastic and 1.47+/-0.5 in the neoplastic cases (p<0.01). The average number of mitoses over 10 high power fields per nodule was 1.31+/-1.55 in the non-neoplastic compared to 42.85+/-30.79 in the neoplastic cases (p<0.01). The average number of multinucleated giant cells over 10 high power fields per nodule was 0.9+/-1.45 in the non-neoplastic compared to 13.9+/-14.66 in the neoplastic cases (p<0.01). In the non-neoplastic cases, collagen, immature fibroblasts and fibroblast activation (excessively plump euchromatic nuclei with single or multiple prominent nucleoli) were scored 0-3 and a combined score, fibroblasts+activation score-collagen was calculated. The non-neoplastic cases were divided into a combined score of 1 (n=27). The 2 groups had similar scores for inflammation and necrosis, but were significantly different (p<0.01) in mitotic index (0.26+/-0.46 vs. 1.89+/-1.65) and number of multinucleated cells (0 vs. 1.4+/-1.6). These results indicate 2 stages in the non-neoplastic nodules: early inflammation, characterized by fibrocytes and abundant collagen, and a pre-neoplastic stage, characterized by activated fibroblasts and reduced collagen.

Perforation of the gastrointestinal tracts of four horses by metallic wires.

The medical records of four horses whose intestines had been perforated by metallic wires were reviewed. Three of the horses developed acute colic, and the other progressively lost weight and became inappetent and pyrexic. Metallic wires were detected either by exploratory laparotomy or postmortem examination. In three of the horses there were adhesions containing an encapsulated metallic wire in the small intestine, and in the other the wire was contained within an abscess with multiple adhesions involving the liver, spleen and mesentery.

The clinical diagnosis of the narcoleptic syndrome.

Sleep-wake habits and control of postural muscle tone were investigated by self-report questionnaire in 183 subjects considered to have the narcoleptic syndrome, 62 subjects with hypersomnia and 10 with obstructive sleep apnoea. Results were compared with those in a group of 188 control subjects with normal sleep wake habits. Excessive daytime sleepiness, determined by the Epworth Sleepiness Scale (ESS), was five times greater in the narcoleptic syndrome than in control subjects (score range 0-24, mean scores +/-SD 19.6+/-3.0; and 4.5+/-3.3 respectively; P<0.001). The propensity to cataplexy, as determined by a rating scale developed to estimate the likelihood of loss of postural tone in response to sudden emotional stimuli, including laughter, was 10 times greater in narcoleptic syndrome than in control subjects (postural atonia total score range 0-600; mean + SD 334+/-122 and 28+/-45, respectively; P<0.001). Narcoleptics had more disturbances of night sleep than controls with episodes of muscle jerking, sleep walking, sleep talking and sleep terrors, as well as sleep paralysis, and higher insomnia self-rating scores. Sleep latency from bedtime to sleep-onset time was shorter in narcoleptics than controls. The hypersomniac group of 62 subjects was heterogeneous. Subsequent investigation showed that 18 subjects (29%) had idiopathic hypersomnia, four (6%) 'incomplete' narcolepsy without cataplexy and 10 (16%) hypersomnia accompanying a mood disorder. The mean ESS scores in this group and in subjects with obstructive sleep apnoea were comparable to those of the narcoleptic syndrome subject group. Mean postural atonia scores were similar to those of control subjects.