Ultrastructural changes in the respiratory lamellae of the catfish, Heteropneustes fossilis after sublethal exposure to malathion

Transmission electron microscopy study of the gills of Heteropneustes fossilis, exposed to 4 mg/liter of malathion (1/3 of LC50) for 24, 48, 72, and 96 h showed significant changes in its ultrastructures. Exposure to the pesticide after 24 h caused a slightly disarrayed condition in the double layered epithelial structure. Lymphatic spaces became more apparent, and a few chloride cells appeared which protruded toward the peripheral margin of the secondary lamellae. Chloride cells were exposed to the exterior by an apical pit. Pinocytosis was observed with marginal folds (MF) originating from the pillar and epithelial cells. Some vascular constrictions were also seen in the capillaries with erythrocytes. After 48 h exposure, the outer epithelial cells were stretched into a thin boundary wall and lymphatic spaces were engorged with plasma exudate. Chloride cells transversed the whole epithelium of the lamella and came into direct contact with lymphoid space and exterior to epithelial lining. Basement membrane of the capillaries became thicker. After 72 h a distorted lamellar epithelium ruptured in a few places allowing many spheroid bodies and some chloride cells come out. Marginal folds of pillar cells migrated into vascular spaces. Basement membrane of capillaries became thicker and blood channels were constricted causing vascular stasis. No erythrocytes were visible. Blood channels were filled with leukocytes and amoebocytes. After 96 h exposure to malathion narrowing of lymphatic spaces, proliferation of epithelial cells and development of pinocytotic vesicles from marginal folds of pillar cell flanges were observed. Only marginal blood channels maintained normal configuration. Vascular stasis due to thickening of the basal lamina were still evident in centrally located blood channels filled with leukocytes. Vascular stasis would likely cause a decrease in respiratory efficiency. This study has revealed that the gills of H. fossilis were affected by a sublethal dose of malathion. The ultrastructural damages to the gills were observed as early as at 24 h exposure, but the most severe damage occurred at 72 h exposure. However, signs of gill structure regeneration were seen in malathion-exposed fish after 96 h.

Oxidation reactions of a bovine serum albumin-bilirubin complex. A pulse radiolysis study

Using the technique of pulse radiolysis, oxidation studies of the bovine serum albumin-bilirubin (BSA-BR) system with radicals like CCl3OO., N3., (SCN)2.-, Br2.- and OH. generated in neutral and alkaline medium are reported. In a neutral solution, BSA protects the bound BR very efficiently from the attack of these radicals. The experimental k/k' values for the reaction of CCl3OO., N3. and Br2.- radicals are 2.46, 1.78 and 2.55 respectively, where k and k' are the bimolecular rate constants for the formation of the semi-oxidized BSA and BR radicals respectively. The calculated ratios from our measurements of rate constants k and k' are 0.16, 0.28 and 1.38 for CCl3OO., N3. and Br2.- respectively. These values indicate protection of BR by BSA from free radical attack. For Br2.- radical-induced oxidation of the BSA-BR system, a radical transfer from protein to BR was observed. OH. shows very fast adduct formation with both BSA and BR. The bimolecular rate constant for the formation of BR-OH adducts at PH 8+/- 0.2 is 9.5 x 10(9) dm3 mol-1 s-1 (540 nm). OH. adds to BSA at neutral pH with a rate constant of 3.0 +/- 1.0 x 10(10) dm3 mol-1 s-1 (305 nm). In the BSA-BR complex, BSA fully protects BR from OH. attack and the (BSA-BR)-OH adduct further reacts with free BR molecule if present in solution.

A comparative study of fine-needle aspiration cytology and histopathology in salivary gland lesions

Background: A wide variety of benign and malignant tumours originate in the salivary glands and insufficient tumour cells make their diagnosis difficult in some patients. The aim of this study was to evaluate the efficacy of fine-needle aspiration cytology in the diagnosis of salivary gland lesions and to correlate cytological findings with histopathology. Materials and Methods: This was a prospective study done from September 2002 to May 2004. Fine needle aspiration cytology was performed in 58 patients with clinically significant salivary gland masses. Results: Fine needle aspiration cytology categorized 67.24% of the salivary gland lesions as neoplastic and 32.76% as non-neoplastic lesions. Amongst the neoplastic lesions, 76.9% were benign and 23.1% were malignant cases. Histopathological examination revealed that 81.05% of the cases were benign and 18.95% were malignant. Fine needle aspiration cytology had a sensitivity, specificity and diagnostic accuracy of 81.82%, 100% and 96.55%, respectively. The positive predictive value and negative predictive value was 100% and 95.9%, respectively. Conclusion: Fine needle aspiration of the salivary gland is a safe and reliable technique in the primary diagnosis of salivary gland lesions. Although, limitations are encountered while predicting specific lesions on cytology, especially when dealing with cystic and some malignant lesions, this study has shown that fine needle aspiration cytology has a high sensitivity, specificity and diagnostic accuracy in diagnosing salivary gland lesions. Keywords: Salivary glands; Fine needle aspiration cytology; Histopathology DOI: http://dx.doi.org/10.3126/jpn.v1i2.5403 JPN 2011; 1(2): 108-113