Browsing by Author "Raj Narayan Ram"

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Ammonium sulfate induced nuclear changes in the oocyte of the fish, Channa punctatus (Bl.)
(Springer-Verlag, 1986) Raj Narayan Ram; A.G. Sathyanesan
[No abstract available]
Carbofuran-induced histopathological and biochemical changes in liver of the teleost fish, Channa punctatus (bloch)
(1988) Raj Narayan Ram; Suman Kumar Singh
In Channa punctatus exposed to a safe dose (4.5 ppm) of the commercial carbamate pesticide carbofuran for 6 months, from January to June, liver exhibited varying degrees of histopathological changes including cytoplasmolysis, nuclear pyknosis, and necrosis leading to complete exhaustion and disintegration of hepatocytes. In some regions of liver, extensive degeneration of proliferated hepatocytes, in close proximity to blood sinuses, looking like darkly stained debris of hepatomass and induction of tumors were indicative of carcinogenic action of this pesticide which may be attributed to its cumulative toxicity during chronic exposure. Apart from this, the rupturing of blood sinus causing invasive infiltration of leukocytes, and detrimental focal necrosis resulting in the complete dissolution of hepatocytes indicated by the presence of debris mass in the necrotic space can be seen. Moreover, in the liver of experimental fish, corresponding to cellular damage, a significant decrease in hepatosomatic index and ascorbic acid content and an elevation in acid and alkaline phosphatase levels were also recorded. These results suggest that carbofuran is capable of inducing histopathological and biochemical alterations in liver which may cause physiometabolic dysfunction in this species. © 1988.
Carbofuran-induced histophysiological changes in thyroid of the teleost fish, Channa punctatus (Bloch)
(1988) Raj Narayan Ram
The long-term toxic effects of continuous exposure for 6 months, from January to June, to a safe dose (4.5 ppm) of a commercial carbamate pesticide, carbofuran, on the histophysiology of thyroid in adult and young (yearling) Channa punctatus, are described in this investigation. In both the experimental groups, thyroid histology exhibited various abnormalities, including hypertrophy, hyperplasia and degeneration of follicular epithelial cells, and reduction in colloid content. Apart from this, in young experimentals, fibrosis of thyroid components, formation of cystic cellular masses, and rupture of blood vessels resulting in hemorrhage can also be seen and suggest direct action of this pesticide on the thyroid. On the other hand, in both treated groups, retardation of thyroid function was also evidenced by significantly reduced thyroidal radioiodine (131I) uptake and CR (conversion ratio of PB 131I in blood serum in relation to total serum 131I uptake) values. Apparently, these histopathological and physiological changes were markedly pronounced in young experimentals, suggesting greater susceptibility of this group to chronic toxicity of carbofuran than that of adults. Thus, on the basis of these results, it can be inferred that carbofuran pesticide, which is washed into water systems in small quantities, induces adverse histophysiological alterations in thyroid, in an age- and size-dependent manner, possibly by acting directly on thyroid and/or through the hypothalamo-pituitary-thyroid axis, in this species. © 1988.
Cythion-induced histophysiological changes in thyroid and thyrotrophs of the teleost fish, Channa punctatus (Bloch)
(1989) Raj Narayan Ram; K.P. Joy; A.G. Sathyanesan
The chronic effects of continuous exposure for 6 months, from January to June, to safe (2.0 ppm) and sublethal (4.0 ppm) concentrations of a commonly used organophosphorus pesticide, cythion, on the histophysiology of the thyroid and thyrotrophs in Channa punctatus are described in this investigation. The pharyngeal thyroid of fish of both treated groups exhibited hypertrophy and hyperplasia of the follicular epithelium and reduction of colloid content. Apart from this, in the fish exposed to 4.0 ppm, some of the follicles were exhausted and transformed into degenerated cystic masses. The presence of free blood cells at these sites suggests rupture of blood vessels and possible phagocytosis. These histopathological changes could be correlated with a significant and dose-dependent reduction of thyroidal radioiodine uptake and conversion ratio (serum protein-bound iodine:total serum iodine) values. After cythion exposure, the thyrotrophs in the pituitary were activated. These results suggest that the thyroid dysfunction caused by cythion may be responsible for the stimulation of the thyrotrophs which in turn stimulated the thyroid follicles through the pituitary-thyroid axis in this species. © 1989.
Effect of a mercurial fungicide on the gonadal development of the teleostean fish Channa punctatus (Bloch)
(1986) Raj Narayan Ram; A.G. Sathyanesan
Channa punctatus exposed to a "safe" concentration of 0.20 ppm of a commercial mercurial fungicide, Emisan (MeEHgCl), for 6 months, from January to June, exhibited significant inhibition of gonadal development as evidenced by their histology and reduced gonadosomatic index. Degenerative changes were also evident. Correlative histological changes were also noted in the pituitary gonadotrophs which were reduced in the exposed fish. Several stage I oocytes exhibited proteinaceous extra and intranuclear "inclusion bodies", and intranuclear "ring-like bodies" associated with the ultimate degeneration of the oocytes. These observations suggest that MeEHgCl inhibits gonadal development through the hypothalamic-pituitary-gonadal axis in this species. © 1986.
Effects of long-term exposure to cythion on the reproduction of the teleost fish, Channa punctatus (Bloch)
(1987) Raj Narayan Ram; A.G. Sathyanesan
The chronic toxic effects of an organophosphorus pesticide on some aspects of the physiology of reproduction in a teleost fish, Channa punctatus, are described in this investigation. Fish exposed to 2·0 mg litre-1 of commercial cythion continuously for 6 months, from January (resting phase) to June (spawning phase), exhibited a significant inhibition of gonadal development and gonadosomatic index. These changes were correlated with less active, and a reduced number of, pituitary gonadotrophs, and biochemical changes in the gonads and liver. The immature oocytes of the experimental fish exhibited cytoplasmic proteinaceous 'inclusion bodies', which ultimately led to their degeneration. The results suggest that cythion may act directly on the gonads and/or through the pituitary-gonadal axis, in this species. © 1987.
Histopathological and biochemical changes in the liver of a teleost fish, Channa punctatus (Bloch) induced by a mercurial fungicide
(1987) Raj Narayan Ram; A.G. Sathyanesan
The chronic toxic effects of a prolonged exposure of 6 months, from January to June, to a 'safe dose' (0·20 mg litre-1) of a commercial organomercurial fungicide, Emisan (methoxy ethyl mercuric chloride: MeEHgCl), on the histophysiology of liver in adults and young (yearlings) of Channa punctatus, are described in this investigation. In both of the experimental groups, liver histology exhibited various abnormalities, including hyperplasia, nuclear pyknosis, fatty necrosis, and degeneration of hepatocytes leading to tumour and syncytium formation, which are indicative of carcinogenesis. Apart from this, blood vessel congestion and oedema were also observed in young treated fish. In the livers of both exposed groups, corresponding with this cellular damage, a marked reduction in hepatosomatic index, levels of total protein and lipid, and an elevation in cholesterol and acid and alkaline phosphatase contents were recorded. However, these alterations were more pronounced in young than in adult fish. These Emisan-induced, histopathological and biochemical changes are suggestive of severe hepatic dysfunction, which may result in the impairment of the physio-metabolic process, in this species. © 1987.
Histopathological changes in liver and thyroid of the teleost fish, Channa punctatus (Bloch), in response to ammonium sulfate fertilizer treatment
(1987) Raj Narayan Ram; A.G. Sathyanesan
In Channa punctatus exposed to safe (100 ppm) and sublethal (500 ppm) concentrations of the commonly used fertilizer ammonium sulfate for 6 months, from January to June, hepatocytes revealed initial hypertrophy followed by exhaustion as evidenced by degranulation, nuclear pyknosis, and focal necrosis. Thyroid follicles exhibited various degrees of hypertrophy, hyperplasia, hyperemia, and reduction in colloid content. Both in the liver and in the thyroid, changes were more pronounced in the 500-ppm-treated fish. These results suggest that this fertilizer, which is washed into the water system in small quantities, may cause dose-dependent dysfunction of liver and thyroid. © 1987.
Inclusion bodies: Formation and degeneration of the oocytes in the fish Channa punctatus (Bloch) in response to ammonium sulfate treatment
(1986) Raj Narayan Ram; A.G. Sathyanesan
In the adult Channa punctatus exposed to 500 ppm of the commonly used fertilizer ammonium sulfate for 6 months from January to June, ovarian growth was retarded significantly. The inhibition of the ovarian growth is reflected on the gonadosomatic index which was significantly reduced as compared with control. Apart from this, in treated fish, several stage-I oocytes exhibited protein-aceous extra- and intranuclear "inclusion bodies" which are apparently due to cumulative toxic effect of ammonium sulfate. These oocytes ultimately degenerate. © 1986.
Long-term effect of ammonium sulfate fertilizer on histophysiology of adrenal in the teleost, Channa punctatus (Bloch)
(Springer-Verlag, 1988) Raj Narayan Ram; Suman Kumar Singh
[No abstract available]
Mercurial induced brain monoamine oxidase inhibition in the teleost Channa punctatus (bloch)
(Springer-Verlag, 1985) Raj Narayan Ram; A.G. Sathyanesan
[No abstract available]
Mercurial induced changes in the hypothalamo-neurohypophysical complex in relation to reproduction in the teleostean fish, Channa punctatus (Bloch)
(Springer-Verlag, 1988) Raj Narayan Ram; K.P. Joy
[No abstract available]