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Biomedical subjects

B Yakobson

Publications and source records attributed to B Yakobson.

35 records · Page 2Linked to original sources

A case of natural hydatidosis in a baboon.

Four large and several smaller cysts of Echinococcus granulosus were found in the liver of a baboon submitted for necropsy. Three of the large cysts had an atypical structure and were packed with a semi-solid mass of collapsed daughter cysts, small cysts containing fluid and involuted membranes. This atypical structure has been reported previously though only in baboons.

Animals↗

Concurrent Hepatozoon canis and Toxoplasma gondii infections in a dog.

A female 1-year-old dog died suddenly and was submitted for necropsy. Numerous grey-tan-colored nodules were seen in the lungs, brain and lymph nodes. Microscopically, the predominant lesion was necrosis associated with numerous Toxoplasma gondii tachyzoites. The parasites reacted positively with anti-T. gondii serum in an immunohistochemical test. Schizonts of Hepatozoon canis were seen in sections of lymph nodes and the spleen.

Animals↗

Eumycetoma caused by Curvularia lunata in a dog.

Curvularia lunata was cultured from black granules found in granulomatous tumefactions excised from the subcutis of a three year old Medium Schnauzer dog. Draining sinuses were present in some of the tumefactions. Accordingly the diagnosis of eumycotic mycetoma was made. This diagnosis was confirmed by histopathological examination. During the four years following the first surgical intervention, several more similar tumefactions were excised on three different occasions. The dog died of chronic renal failure at the age of 8 years. There was no bone involvement or visceral diffusion of the fungus. The granules were examined by scanning electron microscopy. Immunoglobulins in the dog's serum, assessed by a qualitative test, proved to be equal to immunoglobulins in the serum of a control dog. Precipitating antibodies against C. lunata were not found. The dog was treated for 150 days with itraconazole. In spite of good initial results, recurrence of the fungal lesions were observed after the treatment's interruption. Further treatment with itraconazole for 45 days proved ineffective. No side effects of the drug were observed. This is, to the best of our knowledge, the first case in which C. lunata is identified as the causative agent of an animal eumycetoma.

Animals↗

Aspergillus clavatus as the probable cause of a lethal mass neurotoxicosis in sheep.

Sprouted barley grains, the waste product of malt extract production, were incriminated as the cause of a lethal (96% mortality) neurotoxic syndrome in sheep fed the grains. Clinical manifestations, comprising tremors, lameness, abnormal gait, paralysis and death indicated a tremorgenic mycotoxicosis. Whilst 50% of the flock died within 17 days, mortality continued over more than 5 months. Pathological findings were limited to neuronal degeneration and necrosis in the midbrain. Germinating grains were shown to be contaminated with growth of Aspergillus clavatus.

Animal Feed↗

Replication of adeno-associated virus in cells irradiated with UV light at 254 nm.

Irradiation of simian virus 40 (ori mutant)-transformed Chinese hamster embryo cells (OD4 line) with UV light induced a cellular capacity which supported a full cycle of helper-independent adeno-associated virus replication. Monochromatic UV light at 254 nm was about 1,000-fold more effective than UV light at 313 nm, indicating that cellular nucleic acid is the primary chromophore in the UV-induced process leading to permissiveness for adeno-associated virus replication. The UV irradiation and the infection could be separated for up to 12 h without substantial loss of permissiveness. During this time interval, the induction process was partly sensitive to cycloheximide, suggesting a requirement for de novo protein synthesis.

Adenoviridae↗

Enzootic nasal tumour of sheep.

This is the first report of Enzootic Nasal Tumours (ENT) of sheep in Israel. The report includes a detailed clinical, pathological and histopathological description of the syndrome. All 7 affected sheep suffered clinically from serous to muco-purulent nasal discharge and respiratory distress due to obstruction of the upper airway by a neoplastic process. Three of the tumours were histopathologically identified as tubular adenomas, 3 were mucoid adenomas and one was a papillary adenoma. The tumours caused destruction of the turbinate bones and nasal septum.

Adenoma↗

Replication of adeno-associated virus in synchronized cells without the addition of a helper virus.

We investigated the helper-independent replication of adeno-associated virus (AAV) in cells synchronized by pretreatment with hydroxyurea, reversal of polyamine depletion, or physical mitotic detachment. In Chinese hamster cells (OD4 line) treated with hydroxyurea prior to infection. AAV underwent a complete cycle of replication. Transfection of such cells with plasmid-cloned AAV DNAs also gave rise to infectious viral progeny. Synchronization of OD4 cells by reversal of polyamine depletion or mitotic detachment led to independent AAV DNA synthesis (and infectious viral progeny in the case of the former procedure), but these procedures were not as effective as hydroxyurea pretreatment. Independent AAV DNA synthesis was also detected in some other cell lines of Chinese hamster, human, and monkey origin treated with hydroxyurea prior to infection. The results demonstrate that, in contrast to previous notions, the AAV infectious process is not absolutely dependent upon the addition of a coinfecting helper virus.

Animals↗

The chronic course of a probable monensin toxicosis in cattle.

Feedlot calves given monensin in their feed developed an excessive mortality which peaked 3-4 mo after monensin was withdrawn. Typically the calves died suddenly and necropsy revealed areas of paleness in the skeletal muscles (early cases) and in the myocardium (more chronic cases). Histology (in 19 calves) showed swollen myocytes with loss of striation and sarcoplasmic vacuolization, followed by the appearance of necrotic fibres and infiltration with macrophages and neutrophils, and finally local and generalized fibrosis. Calcification was not evident. A differential diagnosis ruled out an etiology of nutritional and toxicological origin, thus leaving the probability of atypical (chronic) monensin toxicosis.

Animal Feed↗

Lymphosarcoma in a spotted hyena, Crocuta crocuta.

Lymphosarcoma of the mesenteric and mediastinal lymph nodes with peritoneal and mediastinal implantations, as well as widespread intravascular metastases and thrombosis with haemorrhages was diagnosed in a spotted hyena.

Animals↗

Mesenteric vein thrombosis in a dog.

A four-year-old, male cocker spaniel was presented for vomiting and anorexia of two days' duration. An elongated abdominal mass was palpated, and abdominal pain was noted. On exploratory laparotomy, a jejunal segment was found to be infarcted transmurally. Histopathology confirmed the diagnosis of mesenteric vein thrombosis. The dog recovered uneventfully following resection of the affected bowel.

Anastomosis, Surgical↗