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Biomedical subjects

H M Sharma

Publications and source records attributed to H M Sharma.

At least 19 recordsLinked to original sources
PubMed2000

Evidence that colitis is initiated by environmental stress and sustained by fecal factors in the cotton-top tamarin (Saguinus oedipus).

Parallel changes in spontaneously occurring inflammation in colonic Thiry-Vella loops and the in-line colon of cotton-top tamarins were studied in a colitis-inducing environment at 8 and 15 months following surgical preparation of the loops. Gross disease severity and numbers of inflammatory/immune cells per unit area of lamina propria in histological sections from endoscopic biopsies were analyzed. Cell counts and severity of colitis declined over time in the Thiry-Villa loops while the disease followed its characteristic course in the remaining large bowel and in the colons of controls. Perfusion of the loops with the animals' feces increased the density of the cellular infiltrate in the lamina propria in parallel with increased severity of inflammation. Electron micrographs of the colonic mucosa showed invasion by microorganisms. The predominant microorganism had characteristics of Helicobacter sp. The results implicate the fecal stream as a factor in the persistence of colitis in the tamarin model. Nevertheless, fecal factors appear not to be the primary trigger, as evidenced by findings that the disease is not expressed in wild-living tamarins and that it enters remission when affected animals are transferred to natural conditions from a colitis-inducing environment. Both an adverse environment and the fecal contents appear to be required for expression of the disease.

Animals↗
PubMed1998

Colitis and colon cancer in cotton-top tamarins (Saguinus oedipus oedipus) living wild in their natural habitat.

The cotton-top tamarin is a nonhuman primate noted for susceptibility to juvenile onset colitis and subsequent colon cancer. About 80% develop colitis in captive environments outside the tropics. The aim was to determine the prevalence of colitis and colorectal cancer in tamarins living wild in their tropical habitat. Endoscopic biopsy was used to compare severity of colitis, inflammatory/immune cell densities, mucosal dysplasia, and occurrence of cancer in wild tamarins in a tropical habitat with tamarins living captive in a temperate climate. Six colon biopsies from each of 69 captives showed severe colitis in 64.5% of biopsies and moderate colitis in 19.5%. Severe colitis was not found in 88 wild tamarins; 13% had moderate colitis. Densities of polymorphonuclear leukocytes, plasma cells, and mononuclear cells in the lamina propria were related directly to the severity of four grades of colitis (normal, mild, moderate, and severe). Histologic or gross signs of carcinoma were detected in 12 captives and low- or high-grade dysplasia in 15. Neither cancer nor dysplasia was found in any of the wild tamarins. The observations suggest that colitis and cancer in the tamarin model are linked to environmental factors.

Animals↗
PubMed1997

Inhibition of low-density lipoprotein oxidation by oral herbal mixtures Maharishi Amrit Kalash-4 and Maharishi Amrit Kalash-5 in hyperlipidemic patients.

Low-density lipoprotein (LDL) oxidation is central to the pathogenesis of atherosclerosis. We have shown previously that the herbal mixtures Maharishi Amrit Kalash-4 (MAK-4) and Maharishi Amrit Kalash-5 (MAK-5) inhibit LDL oxidation induced by cupric ions (Cu+2) and endothelial cells in vitro and that MAK-4 reduces atherosclerosis in Watanabe heritable hyperlipidemic rabbits that were fed this herbal mixture. This study evaluates the antioxidant activity of MAK-4 and MAK-5 in vivo. Ten hyperlipidemic patients prescribed stable hypolipidemic therapy were treated with MAK-4 and MAK-5 for 18 weeks. Plasma lipoprotein, plasma lipid peroxide, and LDL oxidation studies were performed every 6 weeks. Apolipoprotein A, apolipoprotein B, and lipoprotein (a) levels were measured at baseline and 18 weeks. After 12 weeks of treatment with MAK-4 and MAK-5, a time-dependent increase in the lag phase and delay in the propagation phase of oxidation of LDL by Cu+2 and endothelial cells was seen. Lag phases at baseline and after 6, 12, and 18 weeks of MAK-4 and MAK-5 ingestion were 6.66 hours +/- 0.19 (mean +/- standard error of mean), 6.77 hours +/- 0.31, 7.22 hours +/- 0.24, and 18.00 hours +/- 0.73, respectively, for Cu(+2)-catalyzed LDL oxidation. Lag phases were 14.89 hours +/- 0.77, 13.33 hours +/- 0.50, 20.22 hours +/- 0.76, and 20.00 hours +/- 0.79, respectively, for endothelial cell-induced LDL oxidation. The levels of plasma lipid peroxide did not change significantly. No significant changes were seen in the plasma lipoproteins and the levels of apolipoprotein A, apolipoprotein B, and lipoprotein (a). The results show that MAK-4 and MAK-5 inhibit LDL oxidation in patients with hyperlipidemia. Therefore, MAK-4 and MAK-5 may be useful in the prevention and treatment of atherosclerosis.

Adult↗
PubMed1996

Fecal short-chain fatty acids associated with inflammation in cotton-top tamarin model for idiopathic colitis.

This study measured fecal levels of short-chain fatty acids (SCFAs) relative to the severity of colitis in the cotton-top tamarin model of colitis and colon cancer. Severity of colitis was classified as mild, moderate, or severe by subjective scoring of colonic mucosal biopsies and quantification of inflammatory cell infiltrates in the lamina propria. SCFAs were determined by gas chromatography of SCFAs extracted from fresh feces. Tamarins with moderate or severe colitis had significantly reduced levels of fecal SCFAs. The percent dry matter of feces declined significantly in moderate and severe colitis, while total dry matter output per day increased, indicating that moderate and severe colitis in tamarins was associated with diarrhea and increased fecal water loss. In conclusion, this study found colitis in the tamarin model was associated with decreased fecal SCFA levels and progressive inflammation in a pattern similar to human colitis.

Animals↗
PubMed1996

The antioxidant and antiatherogenic effects of MAK-4 in WHHL rabbits.

Oxidized low-density lipoprotein (ox-LDL) plays an important role in atherogenesis. Atheroma formation is reduced significantly in Watanabe heritable hyperlipidemic (WHHL) rabbits by antioxidants such as probucol and vitamin E. The herbal mixture Maharishi Amrit Kalash-4 (MAK-4) inhibits Cu+2 -induced LDL oxidation, and enzymatic- and nonenzymatic-induced microsomal lipid peroxidation. We tested the effect of MAK-4 on the development of atheroma in WHHL rabbits. Eleven rabbits were divided into two groups: controls (n = 5) and a group fed 6% (w/w) MAK-4 (n = 6). Blood was drawn for biochemical analysis every two months and at necropsy, six months after the special diet was started. The aortas were preserved in formalin. The percentage area of aortic arch covered with visible plaque in the MAK-4 group (22.5 +/- 4.2%, mean +/- SE) was significantly reduced (p < 0.01) compared to the control group (47.6 +/- 6.8%, mean +/- SE). The MAK-4 group showed a significant decrease (p < 0.05) in lipid peroxide, and a significant increase (p < 0.05) in glutathione peroxidase and resistance of LDL to endothelial cell-induced and cupric ion-catalyzed oxidation (4.5 h and 5 h lag phase, respectively, for the MAK-4 group; 0 h lag phase for both for the controls). These findings suggest MAK-4 reduces atheroma formation through its antioxidant activity.

Animals↗
PubMed1995

Effect of herbal mixture student Rasayana on lipoxygenase activity and lipid peroxidation.

Brain cellular functions are affected by free radicals. Arachidonic acid and its 12-lipoxygenase metabolites have been proposed as important in enhancing long-term potentiation associated with learning. It has been reported that Student Rasayana (SR), an herbal mixture, improves brain functions. In this study we evaluated the antioxidant capacity of SR and its effect on lipoxygenase activity. Both alcoholic and aqueous extracts of SR inhibited enzymatic- and nonenzymatic-induced microsomal lipid peroxidation in a concentration-dependent manner. The agent concentrations (micrograms/mL) that produced 50% inhibition (IC50) of enzymatic- and nonenzymatic-induced microsomal lipid peroxidation, respectively, were 99.1 +/- 3.9 and 1992.0 +/- 122.7 for the aqueous extract, and 17.7 +/- 0.9 and 646.7 +/- 79.7 for the alcoholic extract. The aqueous extract inhibited soyabean lipoxygenase (SLP)-induced LDL oxidation in a concentration-dependent manner (IC50: 515.5 +/- 11.5), whereas the alcoholic extract enhanced SLP-induced LDL oxidation. Simultaneous addition of aqueous and alcoholic extracts inhibited SLP-induced LDL oxidation. The alcoholic extract (but not the aqueous extract) enhanced the ability of SLP to induce oxidation of linoleic acid. Rats fed 2% (w:w) SR showed inhibition of toluene-induced brain microsomal lipid peroxidation. These results suggest SR improves brain functions through scavenging free radicals as well as increasing the second messenger for long-term potentiation.

Animals↗
PubMed1994

In vitro and in vivo inhibition of microsomal lipid peroxidation by MA-631.

Excess free radicals are linked to many diseases, including aging, atherosclerosis, and cancer. Previously, we have shown that MA-631 (a complex herbal mixture) inhibits human low-density lipoprotein (LDL) oxidation and may play a role in prevention of atherosclerosis. In this study we further evaluated the in vivo and in vitro antioxidant activity of MA-631. Both the alcoholic and aqueous extracts of MA-631 inhibited enzymatic- and nonenzymatic-induced rat liver microsomal lipid peroxidation in a concentration-dependent manner. The thiobarbituric acid-reactive substances (TBARS) values (nmol malondialdehyde (MDA)/mg microsomal protein) were 1.43 +/- 0.18 for microsomes alone (baseline for enzymatic system), 19.63 +/- 2.50 for microsomes + reduced nicotinamide adenine dinucleotide phosphate (NADPH) (oxidation without inhibitor), 9.89 +/- 1.41 for heated microsomes (baseline for nonenzymatic system), and 27.15 +/- 0.08 for microsomes + ascorbate (oxidation without inhibitor). The concentrations (micrograms/2 ml) of MA-631 which produced 50% inhibition (IC50) of enzymatic- and non-enzymatic-induced lipid peroxidation were 15.2 +/- 2.0 and 17.0 +/- 2.6, respectively, for the aqueous extract, and 4.3 +/- 0.8 and 6.4 +/- 1.2, respectively, for the alcoholic extract. A 2% MA-631 (w:w) supplemented diet fed to rats for three weeks inhibited in vivo, toluene-induced microsomal lipid peroxidation in the brain, kidney, liver, and heart. These results imply that MA-631 may be useful in the prevention of free radical-linked diseases.

Animals↗
PubMed1992

Effects of verapamil on the acute toxicity of doxorubicin in vivo.

BACKGROUND: Studies indicating that verapamil substantially enhances doxorubicin levels in certain drug-resistant tumor cells have led to the use of verapamil in combination with doxorubicin in animal and clinical studies of multidrug-resistant tumors. These studies have shown this drug combination to be associated with severe toxic effects. It is important to determine whether verapamil modulates the dose-limiting and potentially lethal cardiotoxicity of doxorubicin and to elucidate possible mechanisms. PURPOSE: The aims of this study were to evaluate the in vivo effects of verapamil on (a) doxorubicin-stimulated cardiac lipid peroxidation and cardiac damage, (b) doxorubicin-induced animal mortality, and (c) biodistribution of doxorubicin to the heart. METHODS: Male (BALB/c x DBA/2)F1 mice were treated with a high dose of doxorubicin (15 mg/kg, injected intraperitoneally), verapamil (25 mg/kg, injected intraperitoneally), or combinations of the two. Lipid peroxidation was determined using the 2-thiobarbituric acid assay for malonaldehyde. Light microscopy was used for histopathologic examination of cardiac tissue. A fluorometric assay procedure was employed to determine doxorubicin levels in the heart. RESULTS: Verapamil was an effective inhibitor of peroxidative damage to myocardial lipids following a high dose of doxorubicin (15 mg/kg, injected intraperitoneally). However, mice treated with verapamil and doxorubicin had a lower survival rate and a higher initial peak concentration of doxorubicin in the heart than those treated with doxorubicin alone. They also demonstrated a higher incidence and severity of degenerative changes in cardiac tissue. CONCLUSIONS: Our findings suggest that verapamil effectively inhibits doxorubicin-mediated lipid peroxidation in vivo but that cardiac lipid peroxidation is not the major limiting mechanism underlying doxorubicin-induced toxicity. A possible explanation for the excess mortality and cardiac injury in mice treated with verapamil plus doxorubicin is that verapamil alters the pharmacokinetics of doxorubicin. IMPLICATIONS: Further studies are necessary for development of safer protocols and/or drug combinations to treat multidrug-resistant tumors. We are currently studying treatment of tumor-bearing animals with a cumulative dosage regimen of doxorubicin in the presence and absence of verapamil.

Animals↗
PubMed1992

Inhibition of human low-density lipoprotein oxidation in vitro by Maharishi Ayur-Veda herbal mixtures.

In this study, we examined the effect of the Maharishi Ayur-Veda herbal mixtures (MAHMs) Maharishi Amrit Kalash-4 and -5 (M-4 and M-5), MA-631, and Maharishi Coffee Substitute (MCS) on low-density lipoprotein (LDL) oxidation and compared the potency of these mixtures to ascorbic acid, alpha-tocopherol, and probucol. LDL was incubated in 95% air and 5% CO2, with or without 3 microM Cu(+2), in the presence or absence of MAHMs, for 6 or 24 h. In a separate experiment, LDL was incubated as above except MAHMs were added at 0, 1.5, and 3.5 h after incubation started to assess their effect on initiation and propagation of LDL oxidation. Our results demonstrate that MAHMs caused concentration-dependent inhibition of LDL oxidation as assessed by thiobarbituric acid-reactive substances and electrophoretic mobility. The MAHM showed more antioxidant potency in preventing LDL oxidation than ascorbic acid, alpha-tocopherol, or probucol. Also, MAHMs inhibited both initiation and propagation of cupric ion-catalyzed LDL oxidation. These results suggest the importance of further research on these herbal mixtures in the investigation of atherosclerosis and free radical-induced injury.

Antioxidants↗
PubMed1991

Inhibitory effects of Maharishi-4 and Maharishi-5 on microsomal lipid peroxidation.

The effects of Maharishi-4 (M-4) and Maharishi-5 (M-5) on microsomal lipid peroxidation were examined in vitro. Rat liver microsomes were incubated with an NADPH-generating system or with sodium ascorbate and an ADP-iron complex to stimulate enzymatic or nonenzymatic lipid peroxidation respectively. Alcoholic or aqueous extracts of M-4 or M-5, when added to these incubation systems, inhibited hepatic microsomal lipid peroxidation in a concentration-dependent manner. The aqueous extract of M-4 was the most effective antiperoxidant in these systems. A 10% (w/v) aqueous extract of M-4 inhibited ascorbate or NADPH-induced lipid peroxidation by approximately 50% when added at volumes of 8 microliters and 3.5 microliters respectively to the incubation mixtures (total incubation volume, 2 ml). These findings suggest that M-4 and M-5, by virtue of their antiperoxidant properties, may be useful in the treatment of free radical-linked drug toxicities and disease states.

Animals↗
PubMed1991

Experimental immune complex-mediated glomerulonephritis in the nonhuman primate.

This study was undertaken to develop a model of immune complex (IC)-mediated glomerulonephritis (GN) in the nonhuman primate that could be used in subsequent studies to examine critically the role of the erythrocyte complement receptor (E-CR) in the pathogenesis of IC-mediated disease. Cynomolgus monkeys were chosen for study because they constitutively express E-CR levels that are either less than, equal to, or greater than that seen in normal man. After immunization with bovine gamma globulin (BGG), the GN induction protocol was begun in 10 cynomolgus by initiating daily i.v. administration of BGG in amounts sufficient to achieve or exceed antigen/antibody equivalence (assessed by the quantitative precipitin assay) for precipitating antibody present in the plasma volume. We found that within eight weeks of daily BGG administration of all the cynomolgus developed IC-mediated GN, irrespective of the initial E-CR level of the animals. However, the high E-CR cynomolgus tended to receive the higher BGG doses because of higher initial antibody levels to BGG. When the total number of glomerular deposits (determined by morphometric studies) per total BGG dose for each animal was plotted against the initial CR/E of that animal, there was a tendency for the animals with higher CR/E levels to have a lower number of glomerular deposits/BGG dose (r = 0.62, P = 0.06). Also, the total number of glomerular deposits correlated with the severity of the GN. During the early weeks of the GN induction protocol, the IC that formed in vivo (assessed by infusion of 125I-BGG) bound in large amounts to the circulating erythrocytes of the cynomolgus with medium or high E-CR levels. However, when tested after the onset of heavy proteinuria, which occurred between weeks 5 and 8 of daily BGG administration, the IC that formed in the circulation bound only poorly to circulating erythrocytes. By this time the E-CR levels had declined to 43 +/- 9% of initial values (P less than 0.01). This study demonstrates that: 1) A workable model of IC-mediated GN has been developed in the nonhuman primate. 2) During the induction of GN, CR/E and the ability of the erythrocyte to bind IC in vivo are decreased significantly. This suggests that an intact E-CR system could play a role in the protection against IC-mediated disease. However, further study will be needed to test that hypothesis critically. The present model should be useful in such studies.

Animals↗
PubMed1990

Antineoplastic properties of Maharishi-4 against DMBA-induced mammary tumors in rats.

Maharishi-4 (M-4), an ayurvedic food supplement, was tested for anticarcinogenic and anticancer properties against 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumors in rats. The 6% M-4-supplemented diet protected DMBA-induced carcinogenesis by reducing both tumor incidence and multiplicity during initiation and promotion phases. The control animals who developed tumors when supplemented with M-4 diet for four weeks showed tumor regression in 60% of cases. There was no significant difference in the food intake or weight gain in rats who were on M-4-supplemented diet compared to control group. Possible mechanisms of action of M-4 are discussed.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1989

Clinical outcome of three discrete histologic patterns of injury in severe lupus glomerulonephritis.

There is a spectrum of glomerular pathology in patients with severe lupus glomerulonephritis (GN) that includes (1) severe segmental GN (SEG) with greater than or equal to 50% of glomeruli involved by active segmental inflammation, (2) diffuse GN, and (3) membranous GN with associated severe SEG or diffuse GN (MGN + PGN). The clinical and laboratory characteristics at entry and at follow-up of 85 patients in a prospective therapeutic trial of plasmapheresis were examined to determine if these morphologic variants had prognostic implications. Addition of plasmapheresis to the therapeutic regimen did not affect outcome, and the two treatment groups were analyzed together. Patients with the three patterns of lupus GN were similar demographically and clinically, and they had similar serum creatinines at entry (SEG, 1.87 +/- 0.28 mg/dL [mean +/- SE], v diffuse GN, 2.11 +/- 0.21, v MGN + PGN, 2.12 +/- 0.26; P = 0.75). Although significant differences were found in the initial serum C3 (SEG, 46 +/- 5 mg/dL, v diffuse GN, 34 +/- 3, v MGN + PGN, 45 +/- 3; P = 0.02) and urinary protein excretion (SEG, 3.6 +/- 0.6 g/24 h, v diffuse GN, 6.0 +/- 0.7, v MGN + PGN, 6.7 +/- 0.9; p = 0.03), none of the clinical or laboratory data predicted the morphologic pattern of the glomerular lesion. Adverse outcomes included defined clinical stop points, nonfatal renal failure, and death. One half of the patients with MGN + PGN (13/26) had an adverse outcome, compared with 5/24 patients with SEG and 11/35 patients with diffuse GN. This trend was supported by actuarial analysis of outcomes showing that patients with MGN + PGN had the lowest cumulative proportion without adverse outcome after 175 weeks of follow-up (MGN + PGN, 0.40, v SEG, 0.77, v diffuse GN, 0.64; P = 0.04). We concluded that (1) at presentation, the specific glomerular lesion in severe lupus GN cannot be predicted on clinical or serological criteria alone; (2) on the basis of morbidity and mortality, cases with all three morphologic variants should be classified as severe lupus GN; and (3) patients with MGN + PGN appear to experience more adverse outcomes than patients with SEG or diffuse GN.

Actuarial Analysis↗
PubMed1989

Acute renal failure with glomerular thrombosis in a patient with chronic scleroderma.

A 48-year-old woman with a 20-year history of scleroderma presented with malignant hypertension, thrombocytopenia, and acute renal failure. Renal biopsy demonstrated vascular changes consistent with scleroderma and glomerular thrombi. Her clinical course was consistent with hemolytic uremic syndrome/thrombotic thrombocytopenic purpura (HUS/TTP)-like syndrome. Plasma exchange therapy was associated with an improvement in renal function and rise in platelet count. This case suggests that acute renal failure in patients with scleroderma can be associated with glomerular thrombi and may improve with plasma exchange therapy.

Acute Kidney Injury↗