Biomedical subjects

N M Sheikh

Publications and source records attributed to N M Sheikh.

6 recordsLinked to original sources

PubMed1999

Effects of long-term consumption of high doses of fish oil concentrates on clinical parameters in male and female rats.

Many studies suggest that a diet supplemented with fish oil concentrates (FOCs) may provide protection against cardiovascular and other diseases. The possible harmful effects of long-term consumption of high doses of FOCs, however, have not been adequately investigated. Corn oil, fish oil (MaxEPA) and various mixtures of the oils were administered by gavage to 120 male and 120 female rats, 5 d/wk for 13 wk at the rate of 5 mL/kg/d. Although MaxEPA had no effect on prothrombin time or activated partial thromboplastin time, it caused a statistically significant diminution of the total serum cholesterol level. Correlations between relative liver and spleen weights and dose levels were positive but a negative correlation was found between dose levels and serum vitamin E concentration. In female rats, the negative correlations between dose levels and serum iron and triglyceride levels were highly significant. The pathology data showed no remarkable lesions in any of the tissues examined. Results of this study suggest that long-term consumption of high levels of FOCs in rats may reduce serum cholesterol and triglycerides and adversely affect serum iron level and relative liver weight in female rats and relative spleen weights in both sexes.

Animals↗

PubMed1997

Chaparral-associated hepatotoxicity.

BACKGROUND: Personal health care practices that may include the use of dietary supplements are common in the United States. Products marketed as dietary supplements are diverse and may include botanicals, vitamins, and/or minerals. Chaparral (Larrea tridentata) is a botanical dietary supplement made from a desert shrub and used for its antioxidant properties. Several reports of chaparral-associated hepatitis have been published since 1990, but a complete picture of the clinical presentation is still unclear. MATERIALS AND METHODS: We reviewed the 18 case reports of adverse events associated with the ingestion of chaparral reported to the Food and Drug Administration between 1992 and 1994. These reports were from health care professionals, state health departments, and individual consumers. RESULTS: Of 18 reports of illnesses associated with the ingestion of chaparral, there was evidence of hepatotoxicity in 13 cases. Clinical presentation, characterized as jaundice with a marked increase in serum liver chemistry values, occurred 3 to 52 weeks after the ingestion of chaparral, and it resolved 1 to 17 weeks after most individuals stopped their intake of chaparral. The predominant pattern of liver injury was characterized as toxic or drug-induced cholestatic hepatitis; in 4 individuals, there was progression to cirrhosis; and in 2 individuals, there was acute fulminant liver failure that required liver transplants. CONCLUSIONS: These data indicate that the use of chaparral may be associated with acute to chronic irreversible liver damage with fulminant hepatic failure, and they underscore the potential for certain dietary supplement ingredients to cause toxic effects on the liver. Health professionals should be encouraged to inquire routinely about the use of dietary supplements and other products, to be alert to potential adverse effects that may be associated with these products, and, finally, to report any serious adverse events associated with these products through the MEDWatch Program of the Food and Drug Administration.

Adult↗

PubMed1993

Dietary carotenoids influenced biochemical but not morphological changes in adult male rats fed a choline-deficient diet.

In a study of the effects of carotenoids, canthaxanthin (CA), beta-apo-8'-carotenal (BA), or beta-carotene in an extract of Spirulina-Dunaliella algae (AE) was fed at 0%, 0.1%, or 0.2% in a choline-deficient (CD) diet. In each of eight groups, 10 adult male Fischer 344 rats were fed diets with designated carotenoid sources and levels or a choline-sufficient diet for 12 weeks. Carotenoids altered some of the changes induced by the CD diet. Increases in enlargement of fatty livers and low plasma cholesterol levels occurred in rats fed 0.2% BA. Plasma retinol was further reduced 35% by BA or AE. BA and AE increased liver total vitamin A about 80% and 305%, respectively. Liver lipid peroxidation was enhanced and plasma alpha-tocopherol was reduced further by 1.0% AE. AE, BA, and CA (mg/g fat) depressed liver alpha-tocopherol about 49%, 67%, and 78%, respectively. The decreased liver alpha-tocopherol was concurrent with an increase in carotenoid stores of CA > BA > AE. Histopathological examination of sections of liver tissue by light microscopy showed fatty and cirrhotic changes in all rats fed CD diets. Histochemical evaluation based on a semiquantitative assay revealed a marked increase in peroxisome enzyme activity in the livers of all CD rats. None of the carotenoids appeared to have any effect on the development of morphological changes in the liver. Although carotenoids can function as antioxidants, they did not prevent changes observed in rats fed CD diets.

Alanine Transaminase↗

PubMed1989

Maintenance of skin viability during in vitro percutaneous absorption/metabolism studies.

The assessment of cutaneous metabolism during in vitro percutaneous absorption studies requires maintenance of the viability of the skin section. With the use of flowthrough diffusion cells, Eagle's minimal essential medium (MEM), Hepes-buffered Hanks' balanced salt solution (HHBSS), or Dulbecco modified phosphate-buffered saline (DMPBS), acting as receptor fluids, were able to sustain aerobic and anaerobic glucose utilization, testosterone and estradiol metabolism, and histopathological appearance of perfused rat skin sections for 24 hr. Fetal bovine serum supplements were not required for survival and appeared to inhibit the extraction of the metabolite estrone from the receptor fluid fractions in estradiol absorption/metabolism experiments. The use of phosphate-buffered saline (PBS) resulted in elimination of aerobic and anaerobic glucose utilization in 12 hr and declining appearance of steroid metabolites in receptor fluid fractions during the 24-hr percutaneous absorption/metabolism studies. Histopathological examination of skin sections perfused with PBS for 24 hr showed autolysis of the viable epidermis and dermis. The results demonstrate that an appropriate receptor fluid, such as MEM, HHBSS, or DMPBS, is required for percutaneous absorption studies in which cutaneous metabolism of the penetrating compound is to be considered.

Analysis of Variance↗

PubMed1981

M-mode echocardiographic observations during and after healing of active bacterial endocarditis limited to the mitral valve.

Analysis of 99 M-mode echocardiograms recorded during and up to 144 months after healing of active bacterial endocarditis limited to the mitral valve in 27 patients disclosed the following: (1) Little to no change occurred in the echocardiographic size of the vegetations during the first 6 weeks after diagnosis and institution of appropriate antibiotic therapy unless a major systemic embolus occurred. (2) The echocardiographic size of the vegetations did not determine the amount of cardiac damage or dysfunction produced by the valvular infection. (3) The larger the vegetations by echocardiogram, the greater was the likelihood of a clinical event compatible with a systemic embolus. (4) The gravest prognostic sign yielded by the echocardiogram was evidence of rupture of chordae tendineae. (5) Although a useful adjunct to diagnosis before appropriate antibiotic therapy was instituted, once bacteriologic cure was achieved, the echocardiogram was of limited value in delineating an active from a heated vegetation. (6) The echocardiographic appearance of the vegetations was not determined by the type of infecting bacterium.

Acute Disease↗

PubMed1981

M-mode echocardiographic observations in active bacterial endocarditis limited to the aortic valve.

Analysis of 37 M-mode echocardiograms recorded during the period of active bacterial endocarditis (ABE) involving the aortic valve (AV) in 17 patients disclosed one or more echocardiographic abnormalities involving the aortic valve cusps or their immediate vicinity in 15 (88%), including "shaggy" echoes indicative of vegetations in 12 (71%). Of the 12 patients with echocardiographic evidence of AV vegetation, 11 developed overt congestive heart failure (CHF) and either died or had AV replacement, and seven had clinical events compatible with systemic emboli; of the five patients without echo-demonstrated vegetations, only one had CHF, none had AV replacement, two died, and one had a systemic embolus. In comparison to our previously reported echocardiographic observations in patients with ABE involving either the mitral (29 patients) or tricuspid valve (23 patients), infection involving the AV was far more liable to produce overt CHF and systemic emboli, to necessitate valve replacement, and to cause death during the period of active infection.

Adult↗