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Biomedical subjects

H M Dutta

Publications and source records attributed to H M Dutta.

At least 19 recordsLinked to original sources
PubMed2005

Diazinon-induced endocrine disruption in bluegill sunfish, Lepomis macrochirus.

An attempt to reveal endocrine disruption in bluegill fish (Lepomis macrochirus) upon exposure to diazinon was made. Fish blood serum was collected and estradiol levels were measured following times of exposure to 60 microg/L of diazinon. Samples were drawn from the fish during each exposure period of 24, 48, 72 and 96 h and 1 and 2 weeks. The sample estradiol levels were compared to those of a control. Ovarian tissue was examined. As necrosis increased within the ovaries, estradiol blood serum levels altered from those of the control sample (101 pg/mL). Histopathology within the follicles became apparent as exposure time to diazinon increased. The changes in the ovarian follicles can be correlated to the estradiol levels in the blood. Mean estradiol level for the control group was 101.53 pg/mL. Estradiol levels from the trial groups varied from those of the control (24 h, undetectable; 48 h, 74.04 pg/mL; 72 h, 57.16 pg/mL; 96 h; 39.15 pg/mL; 1 week, 66.50 pg/mL; 2 weeks, undetectable). It seems that the initial shock experienced by the fish after 24 h of exposure resulted in an undetectable level of estradiol. The level of estradiol initially ascended, but it began to decline and after 1 week of exposure it ascended a little and became undetectable after 2 weeks. Nevertheless, throughout the exposure period the level of estradiol was lower than normal. Severe damage to the mature oocytes may be the reason for undetectable levels of estradiol after 2 weeks of exposure.

Animals↗
PubMed2003

Sublethal effects of diazinon on the structure of the testis of bluegill, Lepomis macrochirus: a microscopic analysis.

A histopathological analysis of the testis exposed to diazinon, an organophosphorus pesticide was conducted. The testis from the control fish exhibited a normal histological structure with a round, oval or somewhat rectangular shaped with closely associated seminiferous tubules. The seminiferous tubules were surrounded by a layer of connective tissue with myoid cells, Leydig cells, blood vessels, lymph vessels and nerves. Upon exposure for 24 h, the overall structure of the testis looked disrupted and more often the sperm cells appeared to be somewhat larger, but spermatid were smaller than that of the control group. The 48 h exposure caused more dense and closely associated seminiferous tubules. The 72 h exposure induced dilation of the seminiferous tubules and their lumen. Ninety-six hours exposure induced more loose and disrupted structures. In this group (96 h), there was a significant reduction in both lumen and seminiferous tubule size in comparison with the control, 24, 48, and 72 h groups. After 2 weeks of exposure hardly any lumen was seen, which imparted more dense and compacted structures. The biometric analysis gave a highly significant increase in the diameter of the seminiferous lumen. After 48 h of exposure a significant reduction was seen in diameter in comparison with that of the control group. Seventy-two hour exposure indicated an increase in diameter, whereas 96 h exhibited another decrease. One week caused the diameter to increase whereas 2 weeks of exposure caused them to decrease again. The increase in diameter of the seminiferous tabule may be caused by weakening of the surrounding connective tissue and myoid cells, due to exposure to diazinon. The change in the diameters of the seminiferous tabules was very irregular. No apparent co-relation was found between the size of the fish, body weight and weight of the testis after they have been subjected to different exposure periods. There was significant change in the germ cells' diameters. As the germ cells are the essential first step in the process of spermatogenesis, their size reduction may hinder the production of viable spermatozoa, endangering the population dynamics. In order to find out the pathways of this pesticide effects, we propose to study the histopathology of pituitary gland a vital organ of the reproductive axis.

Animals↗
PubMed1999

Effect of malathion, an organophosphorus pesticide, on the serum proteins of Heteropneustes fossilis (BLOCH).

The use of pesticides to control pests and to increase food production is a normal process in this modern age. The objective of this study was to determine changes in different serum protein fractions caused by the action of malathion, a commonly used pesticide. We used Indian catfish, Heteropneustes fossilis. The fish were exposed to a sublethal dose of 4 mg/L of malathion for 24, 48, 72, and 96 hr. The LC50 value at 96 hr was found to be 11.676 mg/L. The results showed the formation of three low and four high mobility fractions and the disappearance of some protein fractions at different periods of exposure. The appearance of fractions A, B, and C (low-mobility proteins) may be due to altered immune responses caused by cellular damage. The appearance of new high-mobility fractions (D, E, F, and G) is possibly due to the breakdown of red blood cells and other cellular components. The findings of this study indicate that the high concentration of malathion (4 mg/L) induced more alterations in serum proteins compared with the low concentration (1.2 mg/L) used in our previous study.

Animals↗
PubMed1998

The inhibition of brain acetylcholinesterase activity of juvenile largemouth bass Micropterus salmoides by sublethal concentrations of diazinon.

An effect of diazinon on brain acetylcholinesterase (AChE) activity of juvenile largemouth bass Micropterus salmoides was observed. The exposure concentration started from 1/10 of the 24-h LC50 value, 90 micrograms/liter. The exposure duration was 24 h. Statistically significant and dose-dependent reductions in the mean AChE activities we seen at 90, 180, 270, 360, and 450 micrograms/liter. The results show that juvenile brain acetylcholinesterase activities were significantly inhibited by sublethal doses of diazinon. Inhibition of brain AChE will definitely cause physiological and behavioral modifications that reduce survival ability of the animals at an early stage of growth.

Age Factors↗
PubMed1998

Effect of sublethal levels of malathion on the gills of Heteropneustes fossilis: scanning electron microscopic study.

Scanning electron microscopic studies of the gills of catfish, Heteropneustes fossilis, exposed to sublethal malathion (4 mg/L and 6 mg/L) revealed that 24-hour exposure to 4 mg/L had a mild effect. However, severe damage was found after 48- and 72-hour exposures. After a 24-hour exposure to a 6 mg/L concentration, more severe damage ensued. The microridged epithelial cells of the gill arch became perforated and the central portion of the filament appeared elevated. Numerous mucous gland openings also became visible. After 48- and 72-hour exposures, the damage and structural changes were more pronounced when compared with the 4 mg/L exposure. Enlarged mucous gland openings were found on the gill arch. The lamellar surface had many crevices, elevations and depressions. Broken microridges in the gill arch surface were visible at a 72-hour exposure. At 96 hours of exposure, structural recovery occurred to some extent in both the 4- and 6-mg/L exposures. Corrugation and dissociated epithelium along with some interlamellar bridges were evident after 72 hours of exposure to both concentrations. Such deleterious effects cause reduction in available water supply as well as available respiratory area that may result in decreased oxygen uptake. Consequently, fish may fail to get sufficient oxygen and asphyxiate.

Animals↗
PubMed1996

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.

Journal Article↗
PubMed1986

The intestinal loops of bluegill fish, Lepomis macrochirus.

The structural configurations of the intestinal loops of bluegill fish (Lepomis macrochirus) and a correlation of their probable functional significance have been investigated. The bluegill fish accommodates its relatively large intestine in its smaller body cavity by developing two intestinal loops. Regional variations in the intestinal wall exist due to the presence of the intestinal loops. The structural complexity of the intestine by loop formation has apparently created a problem by posing an obstruction as well as deviation to the smooth flow of food. In order to solve this problem structural modifications in the walls of the intestinal loops are needed, as is observed by the variation in muscle thickness of greater and lesser curvature of both the intestinal loops.

Animals↗