Characteristics and outcome of suspected cerebrovascular disease in dogs: 66 cases (2009-2016)

OBJECTIVES

To characterise the clinical signs of suspected cerebrovascular disease in dogs.

MATERIALS AND METHODS

Medical records of one hospital were searched from November 2009 to December 2016 for dogs that suffered of cerebrovascular disease. We diagnosed cerebrovascular disease based on acute onset, clinical signs and magnetic resonance imaging findings. The medical history, clinical signs, concurrent disease, area of infarction, cerebrospinal fluid results, month at onset and outcome were investigated in the cerebrovascular disease group and in a control group (dogs with brain disorders other than cerebrovascular disease).

RESULTS

A total of 122 CVD cases were extracted from the 5312 patients that visited during the study period. Of these 122 cases, 66 (1.2%) matched the subject selection criteria of our study and were included in the analysis. Forebrain infarction was observed in 51 of 66 cases, of which 24 (47.1%) suffered from seizures. The number of dogs diagnosed with cerebrovascular disease was disproportionately high in August (nine of 59 cases) and December (13 of 59 cases). In the outcome survey, deterioration was observed in 11 of 55 cases.

CLINICAL SIGNIFICANCE

Seizure is an important clinical sign of cerebrovascular disease in dogs. There was a significant seasonal variation in the number of dogs diagnosed with cerebrovascular disease in Japan. Clinical features observed in this report differ from those of previous reports and highlight the need for additional research in this area.

Skin morphology of thyroidectomized rats

We induced hypothyroidism in rats by conducting a thyroidectomy (TD) and investigated subsequent changes in the morphology of the skin, especially that of the epidermis and hair follicles. The 6 rats in the TD group seemed less active than the 3 rats in the control group and had cold, dry paws. All of the rats in the TD group exhibited retarded hair growth 12 weeks after surgery. Histologically, all of the rats in the TD group exhibited epidermal thinning from 12 weeks after surgery. Many hair follicles were in the telogen phase: the bulbs and papillae were involuted and had migrated towards the epidermis. Hair follicle atrophy involving thinning of the outer root sheath and the inner root sheath was often observed. The immunoreactivities of antithyroid hormone receptors alpha and beta in the outer root sheaths of 5 of the TD rats were weaker than those of control rats. Cell proliferation in hair follicles of TD rats was weaker than in follicles of control rats 4 weeks after surgery. It is suggested that decreased expression of TRs and decreased cell proliferation activity in the hair follicles of rats is associated with a lack of thyroid hormone and results in retardation of hair growth.

Morphology of Thyroid Follicular Cells of Methimazole-treated Rats

Thyroids of rats treated with methimazole (MMI) were analysed histologically, immunohistochemically and electron microscopically. Thyroids of MMI-treated rats displayed greater hypertrophy and were heavier than those of control rats. Thyroids of MMI-treated rats were composed of variant or small follicles and contained more columnar cells than those of control rats. Strong staining of thyroid granules by azocarmine G was evident in the apical regions of follicular cells from MMI-treated rats. Anti-thyroglobulin positivity was detected in the apical regions of follicular epithelial cells, especially those of MMI-treated rats. After application of a post-embedding method to detect thyroglobulin, colloidal gold particles were often observed in apical vesicles of MMI-treated rats. Our study suggests that apical vesicles may serve as markers of hyperthyroidism. When the functional state of the thyroid gland is known from histological analysis, use of the Azan stain could provide useful additional information.

Morphological changes in the rat endocrine pancreas within 12 h of intravenous streptozotocin administration

We examined early morphological changes in pancreatic endocrine cells within 12 h of intravenous streptozotocin (STZ) administration (60 mg/kg). Thirty rats were allocated either to a control group (vehicle alone) or to one of four experimental groups tested after 3, 6, 9 and 12 h. Karyopyknosis and cytoplasmic vacuoles were first observed in beta-cell cytoplasm 3 h after STZ administration (STZ-3 h), and the most severe damage was found in beta cells at STZ-12 h. Insulin-positive non-islet cells were observed near the intercalated duct (ICD) and/or centroacinar (CA) cells at STZ-6 h and their numbers peaked at STZ-6 h. The distribution patterns of the insulin-positive cells and those of nestin and insulin-like growth factor-1 were similar and their nuclei were positive for proliferating cell nuclear antigen. Thus, ICD cells and/or CA cells reacted immediately to transform into insulin-secreting cells to replace injured beta cells (or to compensate for the lack of beta cells) within 12 h of STZ administration.

Testicular atrophy after bile duct ligation in chickens

Testicular atrophy associated with biliary obstruction in chickens, produced by the ligation of both extrahepatic bile ducts, was examined grossly, histologically, immunohistochemically, and ultrastructurally. Grossly, reduction in testicular size and volume was evident in chickens that underwent bile duct ligation (BDL). Histologically, there was marked reduction in tubular diameter, peritubular fibrosis, loss of spermatogenic cells, and tubules lined only by Sertoli cells. In addition, Leydig cells, which accumulated in the interstitium of the testes, contained numerous large lipid vacuoles, as determined by electron microscopy. These features suggest that BDL in chickens causes hypogonadism and low serum testosterone.