Browsing by Author "M.T. Rajan"

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Acute toxic effects of mercuric chloride on the mucocytes of the epithelial lining of the accessory respiratory organ and skin of the air breathing catfish Heteropneustes fossilis (Bloch).
(1992) M.T. Rajan; T.K. Banerjee
Acute toxicity of 0.3 ppm mercuric chloride on the mucocytes of the branchial diverticulum and skin of Heteropneustes fossilis results in cyclic increases followed by decreases in the density, area occupancy and volume at different intervals of exposure. The alterations in the two tissues do not follow the same path perhaps due to different modes of action of the mercury salt: The skin comes under direct contact effects, while the branchial diverticulum may be affected by hormonal imbalance caused by a stress effect.
Histopathological changes in the epidermis of the air breathing catfish Heteropneustes fossilis exposed to sublethal concentration of mercuric chloride.
(1993) M.T. Rajan; T.K. Banerjee
Histopathological alterations induced by the sublethal concentration of (0.03 ppm) mercuric chloride solution on the epidermis of the fresh-water catfish Heteropneustes fossilis have been studied. It induces slow but significant histopathological changes in the various cellular components of the epidermis. It induces vacuolization, necrosis and pycnosis of the nuclei of the epithelial cells which subsequently shed. Loosening of epithelial cells of the outermost and middle layers following degeneration of the intercellular material and widened intercellular spaces is another important alteration. Prolonged mercury treatment also causes a gradual decrease in staining intensity for sulphated glycosaminoglycans in the outer border of the most superficial layer epithelial cells. The glandular elements (club cells and mucocytes) also get affected, showing cyclic degeneration followed by regeneration.
Histopathological Changes Induced by Acute Toxicity of Mercuric Chloride on the Air‐breathing Organ (Branchial Diverticulum) of the Live Fish Heteropneustes (= Saccobranchus) fossilis (BLOCH) Histopathologische Veränderungen an den Atmungsorganen des Fisches Heteropneustes (= Saccobranchus) fossilis (BLOCH) aufgrund der akuten Toxizität von Quecksilberchlorid
(1993) M.T. Rajan; T.K. Banerjee
Toxicity induced by 0.3 ppm (96 ppm (96 h LC50 value) mercuric chloride solution on the histomorphology of the innerlining of the air breathing organ (branchial diverticulum) of Heteropneustes fossilis has been described. The outer cell layers of the epithelial lining show cyclic necrosis leading to shedding with ultimate haemorrhage and drainage of blood into the lumen causing decrease in the number of blood islets. Simultaneously the epithelium regenerates causing hyperplasia of its cells and increased gas diffusion distance impairing normal aerial respiration. Also the number of foldings decreases and the secondary lamella like structures fuse together. This results in smoothening of the inner lining of the air sac. Later reappearance of the blood islets, secondary lamellae and foldings of the inner lining are observed along with the repair of the epithelium. Damage of the repaired inner lining follows again. Copyright © 1993 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Histopathological changes induced by acute toxicity of mercuric chloride on the epidermis of freshwater catfish- Heteropneustes fossilis (Bloch)
(1991) M.T. Rajan; T.K. Banerjee
The toxic effects of 0.3 ppm (96-hr LC50 value) of mercuric chloride solution on the epidermis of Heteropneustes fossilis at different time intervals have been studied. The epidermis reacts instantaneously by secreting a profuse amount of slime, especially due to hyperactivity of the goblet mucous cells which subsequently degenerate and get lost. Later, all other cell types also get entangled in the degenerative process. The damaged cells, especially the club cells, get sloughed at the surface, forming a thick crust of debris from the degenerating cells. Side-by-side regeneration of the epidermis also continues from the lower layers of the intact tissue with the addition of all the cell types. However, even before attaining maturity, these budding cells, especially the club cells, show signs of degeneration, their degeneration occurring faster than their regeneration. Thus most of the space left behind by the degenerated club cells gets quickly filled with haphazardly arranged polygonal epithelial cells, giving the epidermis an altogether different morphology. © 1991.
Melanophore indexing: a new bio-assay technique for the analysis of acute heavy metal (HgCl2) toxicity.
(1995) M.T. Rajan; T.K. Banerjee
Toxicity of 0.3 ppm (96 h LC50 value) and 0.03 ppm of mercuric chloride on the melanophores of the skin at different time intervals has been studied. Mercury treatment causes immediate increase in the number and size of the pigment cells. Subsequently these pigment cells form a dense matting of melanophore network with their cell processes interlacing with those of their neighbours. These cells later show degeneration and lysis releasing large quantity of pigment granules into the intercellular spaces in the dermis. Later the pigment cells regenerate several times each followed by degeneration in a cyclic manner. Prolonged treatment with sublethal concentration of mercuric chloride does not show significant alteration in the melanophore density and size. Statistical analysis and wide spread destruction of melanophores observed during 4-6 days of exposure might help in testing water samples contaminated with lethal concentration of heavy metal salts.