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19952
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Subject: Veterinary Pathology × End date: 1995 × Start date: 1995 ×
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    ThesisItemOpen Access
    Pathology of hypothyroidism in pigs
    (Centre of Excellence in Pathology, College of Veterinary and Animal Sciences,Mannuthy, 1995) Prasanna, K S; KAU; Sreekumaran, T
    An experimental model of hypothyroid state was induced in piglets, using thiourea with the objectives of studying the sequence of clinico pathological changes and its influence on the animal health and growth. Tweleve Large White Yorkshire male piglets of 2 – 3 months age were selected for the study. The animals were divided into control group of six animals and experimental group of six animals. Experimental hypothyroidism was induced by feeding thiourea daily for a period of three months at the dose level of 50 mg per kg body weight. Haemogram, body weight, plasma proteins, serum cholesterol and serum thyroxine values were estimated at periodic intervals. The piglets were subjected to detailed autopsy after sacrifice. Gross lesions were recorded and detailed histopathological examination of tissues was carried out. During the course of experiment all the experimental animals recorded stunted growth and appreciable reduction in feed intake and alopecia of neck and shoulder regions. There was significant increase in blood cholesterol values and plasma protein level in thiourea fed group. A significant reduction in serum thyroxine level was also recorded. There was significant increase in the relative weight of thyroid, adrenal and pituitary glands of experimental animals. Gelatinisation of subcutaneous fat and dilatation of right ventricles were common findings at autopsy. Histologically the thyroid glands exhibited varying degree of hyperplastic changes and depletion of colloid in the follicles. Hyperplasia and hypertrophy of the lining epithelium was also observed. Predominant histological changes in the pituitary was hyperplasia and hypertrophy of the basophil cells and degranulation of the acidophil cells. Adrenal glands showed diffuse hyperplasia of zonafasiculata and accessory cortical nodule formation. Skin revealed acanthosis, hyperkeratosis and keratinisation of harifollicles. In all the hypothyroid animals testis showed varying degree of tubular degeneration. A random survey study was conducted to assess the thyroid status of pigs from different parts of Kerala using serum thyroxine as the marker. This concluded that most of the animals had the normal range of serum thyroxine levels.
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    ThesisItemOpen Access
    Assessment of the role of aflatoxin in the aetiology of carcinoma of the mucosa of the ethmoid
    (Centre of Excellence in Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1995) Surinder K, Chaudhary; KAU; Rajan, A
    The present investigations were planned to assess the role of aflatoxin B1 (AFB1) and /or virus in the aetiology of ethmoid carcinoma using pig as a model in vivo and bovine ethmoid mucosa culture in vitro. Thirty – two, large white Yorkshire piglings of two – three months age were procured from the University pig Breeding Farm, Mannuthy and divided at random into four groups of eight each. The pigs in group I and group II were administered aflatoxin B1 (0.070 mg/kg b.wt/inoculums by intravenous route at weekly interval for six months) and /or ethmoid tumour extract (2 ml/pig/inoculums, intranasally, at fortnight interval for three months). The pigs in group III were administered ethmoid tumour extract alone, while the pigs in group IV were kept as negative controls. During the period of observations of 18 months all the pigs of different groups given AFB1 and /or ethmoid tumour extract appeared healthy and no clinical manifestation of the carcinoma of the mucosa of ethmoid was observed. However, there was appreciable reduction in the weight and mild degree of depression. In the AFB1 treated pigs, sacrificed at 9, 12, 15 and 18 months of investigation, the ethmoid mucosa had grayish white, soft and oedematous appearance along with scattered small pale elevations at necropsy. Histologically, the ethmoid mucosa exhibited hyperaemia, varying degree of mononuclear cell infiltration and fatty degeneration in the initial stages. In the later stages, there was proliferation of mucous glands showing acinar, tubular or papillary arrangements. Occasionally papillary projection of the surface epithelium and focal squamous metaplasia were also observed. Ultrastructural features of the cells of the ethmoid mucosa consisted of both productive and degenerative changes. The cells had sparse cytoplasmic organelles. The poor cytoplasmic contents and irregular nucleus with nucleolar margination were the other electron microscopic features observed in the ethmoid mucosa of AFB1 treated pigs. AFB1 in the range of 43.12 – 139.43 ppb could be detected in the blood of 52.37 percent of the ethmoid tumour bearing cattle analysed in the present study. The blood samples from the AFB1 treated pigs were positive for AFB1 (40-160 ppb) upto 10 days after the withdrawal of treatment whereas AFM1 could be detected in blood sample of one pig only upto 3 days after the treatment. The ethmoid mucosa analysed after 3 months and at subsequent specified intervals was consistently negative for AFB1 and AFM1. By concerted efforts cells of the mucosa of the ethmoid were established in vitro. AFB1 treatment of long term epithelial cultures intiated from the primary culture of bovine ethmoid mucosa origin resulted in morphological transformation accompanied by increased growth in soft agar and cytochemical positivity of gamma glutamyl transpeptidase. This confirmed the tumourigenicity of AFB1. The xenotransplantation of these in vitro transformed epithelial cells in mice was not successful. Electron microscopic studies of the cells of the carcinoma of the ethmoid mucosa in spontaneous cases of cattle revealed varying ultrastructural features. The neoplastic cells were either well differentiated secretary structures or undifferentiated ones. Desmosomes and tight junctions were seen between the epithelial cells. Endoplasmic reticulum and mitochondria varied in their contents and degree of disorganization. Nucleus was highly pleomorphic and predominantly euchromatinic. The retroviral like particles were demonstrated intracellularly and occasionally in extracellular spaces in the neoplastic cells of 7 tumour bearing cattle. Similar particles were also seen in the cell free ethmoid tumour extract in three of21 tissues examined.