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Biomedical subjects

H Tewari

Publications and source records attributed to H Tewari.

16 recordsLinked to original sources
PubMed2002

Posterior vitreous wick syndrome: a potential cause of endophthalmitis following vitreo-retinal surgery.

Endophthalmitis following pars-plana procedures such as a vitrectomy vitreo-retinal procedures has been infrequently reported in literature. The cited incidence is about 0.1% to 0.2%. In the 8 cases of endophthalmitis that have been reported in literature, the prognosis has been indicated as very poor due to a delay in diagnosis (1-3). Also, no possible source of an inoculum of the pathogenic organism reaching the vitreous cavity has been considered in these reports. We have encountered a few cases of endophthalmitis following vitreo-retinal surgeries at our tertiary eye care centre. Here again not being able to identify the possible source of infectious spread, we now report for the first time in literature, a new entity, the 'posterior vitreous wick syndrome'. This potential source of infectious spread, to the best of our knowledge, has not been considered earlier. We describe the patho-mechanism of the 'posterior vitreous wick syndrome' and also suggest methods of reducing its occurrence during vitreo-retinal procedures. This could also be the patho-mechanism of endophthalmitis following inadvertent loss of scleral integrity during extraocular surgeries like retinal detachment surgery and strabismus surgery (4,5).

Adult↗
PubMed1992

Short- and long-term effects of copper on the rosy barb (Puntius conchonius Ham.).

The rosy barb (Puntius conchonius) was exposed to copper (Cu) for short (48 hr) and long (8 weeks) terms and effects on enzyme activities and biochemical variables in the blood and tissues were examined. In vivo exposure to 571 micrograms CuSO4/liter (96-hr median tolerance limit (TLm)) for 48 hr stimulated to varying degrees acid phosphatase (AcP), alkaline phosphatase (AlP) (except in the liver), and acetylcholinesterase activities in selected tissues. The alanine aminotransferase and lactic dehydrogenase (LDH) (except in the heart) activities were inhibited to varying degrees in vivo. In vitro, the presence of 10(-6) M Cu suppressed enzyme activities in the tissues examined, with a few exceptions such as AcP in ovaries and gut, AlP in liver, gills, gut, and testes, and LDH in liver. Hyperglycemia, hyperlactemia, hyperproteinemia, elevated blood free fatty acid (FFA) levels, and hypocholesterolemia were manifested in the fish exposed to 190 micrograms CuSO4/liter (1/3 96-hr TLm). Effects on the tissues included glycogenolysis (liver and skeletal muscles), glycogenesis (brain and heart), a marked rise in hepatic proteins, accumulation of FFAs in liver and skeletal muscles, and reduction in hepatic and gonadal cholesterol contents. After 8 weeks, a trend toward recovery was noted in the biochemical variables (except blood and hepatic protein levels).

Animals↗
PubMed1992

Morphology of the adrenal homologues in two hillstream teleostean fishes from India.

In Garra gotyla and Pseudecheneis sulcatus, the interrenal and chromaffin tissues represent homologues of the adrenal cortex and medulla, respectively, and are confined to the largely lymphoid head kidneys in a bilaterally symmetrical topographical pattern. Together they form a collar round the postcardinal vein, with a thickness of 300 microns in Garra gotyla and 150 microns in Pseudecheneis sulcatus. Distributionally, the interrenal tissue conforms to Nandi's type III and type I and the chromaffin tissue to type V and type III in Garra gotyla and Pseudecheneis sulcatus, respectively. The interrenal cells in these species are polygonal, cuboidal or columnar, and are filled with coarse basophilic cytoplasm. The chromaffin cells form syncytial patches and have sparsely granular cytoplasm.

Adrenal Glands↗
PubMed1991

Effects of endosulfan on the blood and organ chemistry of freshwater fish, Barbus conchonius Hamilton.

Prolonged exposure (4 weeks) to 6.72 ppb of the organochlorine insecticide endosulfan induced disturbances in the blood and organ chemistry values of a common fish, Barbus conchonius. In blood the total lipids, cholesterol, and proteins were decreased in comparison to unexposed controls, while the free fatty acids (FFA), glucose, total phosphorus, and lactate were increased. Total lipids, FFA, and proteins were augmented in liver; cholesterol, in liver and ovary; and phosphorus and glycogen, in skeletal muscles. Compared to the controls, a decrease was seen in the total lipids (skeletal muscles and ovary), glycogen (liver, brain, and heart), and cholesterol (testes). Hyperlipemia, hyperproteinemia, and hyperlactemia persisted during a recovery period of 1 week in clean water following endosulfan poisoning.

Animals↗
PubMed1991

In vivo and in vitro effects of cadmium on selected enzymes in different organs of the fish Barbus conchonius Ham. (rosy barb).

1. Enzyme modulation by cadmium in selected organs of the fish, Barbus conchonius (rosy barb), was investigated in vivo (48 hr exposure to 12.6 mg/l cadmium chloride) and in vitro (10(-6) M cadmium chloride). 2. The acetylcholinesterase (AchE) activity was depressed in the gills but stimulated in the skeletal muscles and brain in vivo. The hepatic, branchial, and renal acid phosphatase (AcP) activity decreased marginally in vivo but it was significantly increased in the gut and ovary. In vitro, except for the liver, the AcP activity was depressed in the selected organs. Collaterally, gut alkaline phosphatase (AlP) was significantly inhibited but a pronounced stimulation was noted in the kidneys and ovary in vivo. In vitro, the AlP activity was conspicuously elevated in the kidneys and gut, and moderately in the gills. 3. Cadmium inhibited the glutamate-oxaloacetate and glutamate-pyruvate transaminases (GOT and GPT) in the liver, gills and kidneys in vivo. In vitro, the GOT and GPT activities were decreased in the liver, gills and kidneys. The lactic dehydrogenase (LDH) was significantly stimulated by Cd in the heart in vivo but in vitro the metal inhibited the enzyme in the gills. 4. Enzymes in the liver, followed by those in the kidneys and gills seem to be most seriously affected by Cd poisoning in this fish.

Acetylcholinesterase↗
PubMed1991

Individual and combined toxicity of common pesticides to teleost Puntius conchonius Hamilton.

Individual and combined toxicity of three pesticides, endosulfan, phosphamidon, and aldicarb was evaluated in P. conchonius. The 48 hr LC50 was 21.36 and 446.5 ppm respectively for endosulfan and phosphamidon. When tested jointly, 48 hr LC50 for different ratios of these pesticides were 0.332 (IE:3P), 0.224 (IE:1P), and 0.178 ppm (3E:1P). The cotoxicity coefficients for these combinations were 1793, 3986, and 10009, respectively. An equitoxic mixture of endosulfan, phosphamidon, and aldicarb yielded a 48 hr LC50 of 130.5 ppm. An enhanced toxic impact is indicated when the pesticides are present together rather than as individual compounds.

Aldicarb↗
PubMed1990

Use of the fish enzyme system in monitoring water quality: effects of mercury on tissue enzymes.

1. Rosy barb (Puntius conchonius) were exposed to 181 micrograms/l mercuric chloride for 48 h and the activity of acid and alkaline phosphatases (AcP and AIP), aspartate aminotransferase (AAT), alanine aminotransferase (AIAT), lactic dehydrogenase (LDH), and acetylcholinesterase (AchE) were measured in vivo in several organs. 2. The AcP activity was inhibited in the liver, gills, kidneys, and gut but stimulated in the gonads. With the exception of kidney, the AIP activity showed an increase in all the organs examined. The AAT and AIAT were generally inhibited in different organs. An increase in LDH activity occurred in the cardiac and skeletal muscles while the AchE activity was considerably lowered in the brain, gills, and liver. 3. In vitro exposure to mercury at concentrations ranging between 10(-10) and 10(-4) M, inhibited the AIP, AAT, AIAT, LDH, and AchE activities in the tissues examined. The AcP activity was also depressed in all the tissues except in the testes, in which a marginal increase was noted. 4. The in vivo and in vitro effects of Hg were not of similar quality implying sequestration of toxic cations in the intact animals.

Acetylcholinesterase↗
PubMed1989

Cadmium nephropathy in a freshwater fish, Puntius conchonius Hamilton.

Renal pathology was examined in a freshwater fish, Puntius conchonius, during a 12-week exposure to 500, 630, and 840 micrograms CdCl2/liter (1/25, 1/20, and 1/15 fractions of the 96-hr TLm, respectively). Multifocal tubular epithelial degeneration including severe vacuolation and nuclear pyknosis and karyorrhexis composed the most obvious lesions. The degenerative changes were found mainly in the proximal segments, while the distal segments and the collecting tubules and ducts remained unaffected. Collapsed and shrunken glomeruli and swollen Bowman's spaces were also frequently observed. The cadmium-exposed fish appeared heavily stressed and moribund. A comparison of the renal pathology with that of other fishes and mammals and possible mechanisms of cadmium nephropathy are discussed.

Animals↗
PubMed1988

Branchial pathogenesis in a freshwater fish, Puntius conchonius Ham., chronically exposed to sublethal concentrations of cadmium.

Effects of sublethal concentrations, 630 and 840 micrograms/liter (0.05 and 0.066 fractions of the 96-hr LC50), of cadmium chloride on the gills of a freshwater fish, Puntius conchonius, were examined light microscopically during a 12-week exposure. The secondary gill lamellae showed disrupted epithelium, necrosis, accumulation of cellular debris, capillary congestion, and wilting of the pillar cell system. Hypertrophy and hyperplasia of chloride cells as well as partial or complete fusion of secondary lamellae also occurred in the Cd-exposed fish. Branchial lesions together with coagulation film anoxia are likely to result in serious respiratory distress and related tissue hypoxia.

Animals↗