Search PubMed⌕ Search

Biomedical subjects

S Mobarhan

Publications and source records attributed to S Mobarhan.

At least 19 recordsLinked to original sources
PubMed2003

Modulation of endothelial cell inflammatory integrins and stress markers with rh-factor VIIa in patients with advanced chronic hepatitis C.

Individuals with chronic hepatitis C (CHC) progress to cirrhosis and hepatic cancer. Individuals with advanced CHC are coagulopathic and can manifest fibrinolysis. The coagulopathy is a consequence of hepatocytic dysfunction. The fibrinolysis represents a response to local endothelial cell injury, and is of a low-grade. Based upon this hypothesis, the effect of the infusion of recombinant human factor VIIa (rh-FVIIa) on endothelial cell inflammatory integrins and measures of endothelial stress were determined in 17 individuals with advanced CHC. Immediately prior to the infusion of rh-FVIIa, the plasma levels of tissue factor (TF), Thrombomodulin (TM), human soluble ICAM-1 (hs-ICAM-1), human soluble VCAM-1 (hs-VCAM-1), human soluble L-Selectin (hs-L-Selectin), the prothrombin time and the activated partial thromboplastin time were determined. The same parameters were assayed at 5, 10, 30, 120, 240 and 360 min after infusion. TF and TM levels were very high at baseline consistent with a vascular endothelial stress response. Similarly hs-ICAM-1, hs-VCAM-1 as well as L-Selectin levels were increased. Thirty minutes after the infusion, a marked reduction in ICAM-1 and VCAM-1 and to a lesser degree L-Selectin levels was observed. This reduction persisted for 360 min. No change in measures of fibrinolysis [plasminogen activator inhibitor-1 (PAI-1), total tissue factor pathway inhibitor (t-TFPI), activated tissue factor pathway inhibitor (TFPIa), d-dimers (DD), FSP and fibrinogen levels] occurred. In addition, no change in plasma Annexin-V was observed. Based upon these data it can be concluded that: (1) rh-FVIIa corrects the coagulopathy seen in advanced CHC; (2) reduces endothelial cell injury and/or stress as evidenced by the TF, TM, hs-ICAM-1 and hs-VCAM-1 levels in plasma; (3) these changes in coagulation occurred without inducing a propagated vascular thrombosis.

Adult↗
PubMed2002

Accumulation and interactions of beta-carotene and alpha-tocopherol in patients with adenomatous polyps.

OBJECTIVE: The aims of the present study were: (1) to determine whether short-term supplementation of beta-carotene (BC) or vitamin E (VE; alpha-tocopherol) would result in their respective accumulation in normal colonic mucosa and in adenomatous polyps; (2) to determine whether the intake of BC would interfere with the concentration of VE in these target tissues. DESIGN: Blood and colonic biopsy samples were taken before and after supplementation. SUBJECTS: Eighteen volunteers with colonic adenomatous polyps were enrolled into this study. INTERVENTIONS: The supplementation lasted for 43 days and patients were examined over the whole period. Subjects were randomised into four groups according to the four different supplementations: placebo, natural BC (25 000 IU/day), natural VE (400 IU/day), combination BC/VE. RESULTS: Initially we were aiming for recruitment of 20 patients in each group, however after 2 y of study (1997-1999), we terminated the study because of slow recruitment and analysed the data. In placebo subjects after supplementation, the plasma concentrations of BC and VE remained unchanged, however only two patients were recruited in this group and therefore we did not include this group in our final analysis. In BC group, the plasma BC concentrations increased significantly (P<0.001), while VE concentrations were unchanged. In VE group, VE concentrations increased (P<0.01) and BC did not change, and in BC/VE group both BC (P<0.001) and VE levels (P<0.01) increased significantly. After supplementation, the tissue concentration of BC in normal colonic mucosa in BC group increased significantly (P<0.01) while the VE concentration did not change. In VE group, the concentration of VE in normal colonic mucosa increased slightly but did not reach statistical significance. However, VE concentration increased significantly (P<0.05) in the polyps of this group. In BC/VE group, in which patients received the combination treatment, the BC concentration of normal colonic mucosa increased (P<0.05) but, surprisingly, the VE concentration decreased significantly (P<0.01). Interestingly in the polyps, although the BC concentration increased (P<0.01), the concentration of VE was reduced moderately but did not reach statistical significance. CONCLUSIONS: Supplementation of BC in doses used in this study may have significantly interfered with the VE concentration in the examined tissue and probably with its metabolic pathway.

Adenomatous Polyps↗
PubMed2001

Effects of diets containing fish oil and vitamin E on rheumatoid arthritis.

Animal, tissue culture, and human studies have evaluated the effects of fish oil supplementation in patients with rheumatoid arthritis (RA) over the last two decades. These studies have clearly shown potentially beneficial changes in cytokine and eicosanoid metabolism. The overall clinical improvement, however, has been only moderate. European clinical trials have shown significant pain reduction in patients with RA treated with vitamin E. A recent animal study in RA-prone mice evaluated the effects of vitamin E in addition to omega-3 and omega-6 fatty acids on cytokine and eicosanoid production. The authors suggest that vitamin E might have an additional positive effect on autoimmune disease by decreasing proinflammatory cytokines and lipid mediators. Is this information ultimately important in terms of dietary advice for patients with RA? Are further clinical trials indicated? The following article will present a brief critical review.

Arthritis, Rheumatoid↗
PubMed2001

Preventive role of dietary fiber in gastric cardia cancers.

The incidence of adenocarcinoma of the esophagus and gastric cardia is increasing. Many factors are presumed to be associated: symptoms of gastroesophageal reflux disease, tobacco use, alcohol consumption, dietary factors, and obesity. A recent large population-based case-control study evaluated the association between dietary fiber intake and cancers of the gastric cardia and esophagus. This interesting study indicated that high intake of cereal fiber may significantly decrease the risk of gastric cardia cancer. More research is needed on this topic in the hope that dietary intake may decrease the incidence of these cancers.

Adenocarcinoma↗
PubMed2000

Nutrition support for individuals with liver failure.

The prevalence of liver diseases is increasing in the United States, particularly as a result of the recent hepatitis C epidemic. In the past, patients who developed fulminant hepatic failure or cirrhosis owing to a chronic liver disease were likely to expire. During the last 15-20 years, liver transplantation has given these patients a chance at survival. Progressive nutrition deficiencies and muscle wasting are universal problems in these patients. Left untreated, the progressive wasting of liver disease leads to infection and an increased risk of death owing to infection both before and after transplantation. Aggressive nutritional support is essential to optimize the care of these patients and to enable them to obtain and survive a liver transplant and gain access to a new life following a successful liver engraftment.

Aged↗
PubMed2000

Association between body mass index and adenocarcinoma of the esophagus and gastric cardia.

Obesity is an increasing problem for industrialized nations. The incidence of adenocarcinoma of the esophagus and gastric cardia has also risen during the past two decades. A recently published population-based study attempted to relate this rise to increases in obesity or body mass index. Obesity may not only increase the risk for adenocarcinoma of the upper gastrointestinal tract, but it may also increase the risk of colon cancer and overall mortality. More research is needed to understand obesity's health impact and ways to control this epidemic.

Adenocarcinoma↗
PubMed2000

Chronic daily low dose of 4-methyl-5-(2-pyrazinyl)-1,2-dithiole-3-thione (Oltipraz) in patients with previously resected colon polyps and first degree female relatives of breast cancer patients.

The chemoprevention agent oltipraz, one of the most active chemopreventive compounds in preclinical studies, has been shown to induce glutathione-S-transferase (GST) activity in animals. Oltipraz was evaluated in a Phase I trial at daily oral doses of 20 mg (L1), 50 mg (L2), and 100 mg (L3) and twice weekly doses of 125 mg (L4) taken for 6 months with 6 patients entered at L1 and L2 and 7 patients entered at L3 and L4 (26 subjects: 19 females and 7 males). The subject population included patients with previously resected colon polyps and first-degree female relatives of breast cancer patients. Patients with resected colon polyps underwent rectal biopsy for GST and glutathione (GSH) analyses. Of the 26 subjects, the following completed 6 months of therapy: 4 of 6 patients (L1), 4 of 6 patients (L2), 5 of 7 patients (L3), and 4 of 7 patients (L4). Toxicities were mild to severe and included: gastrointestinal symptoms, photosensitivity/heat intolerance, and neurological symptoms. Monthly plasma samples were obtained 2-3 h after oltipraz ingestion with minimally detectable plasma concentrations at L1. There was a significant difference in mean oltipraz concentration across the four doses, with no significant differences in mean oltipraz concentration over time. Rectal tissue and lymphocyte GSH and GST were variable, with no significant difference in mean levels across doses. At the 100-mg/day dose (L3), 1 patient experienced significant increase in rectal tissue GSH and GST activity, whereas 3 additional patients (L1 and L4) had >50% increase in tissue GSH. Lymphocyte GSH level was significantly related to plasma oltipraz concentration. There were no significant correlations between plasma oltipraz concentration and lymphocyte GST level nor any significant correlation between plasma concentration and percentage of change in tissue GSH or GST. Further investigation of dose/schedule and biological end points is ongoing.

Anticarcinogenic Agents↗
PubMed1999

Calcium and the colon: recent findings.

Results of recent intervention trials suggest that calcium from low-fat dairy foods modulates the rate of human colon cell proliferation and that calcium supplementation reduces the rate of colonic adenomatous polyps. Further research from longer-term studies is necessary to confirm these findings.

Animals↗
PubMed1998

Beneficial effect of a bile acid resin binder on enteral feeding induced diarrhea.

OBJECTIVES: Diarrhea is a complication of enteral feeding, occurring in up to 68% of critically ill patients. We hypothesized that prolonged fasting results in abnormal bile acid homeostasis. Subsequent enteral feeding then causes a relative luminal excess of bile acids, which leads to choleretic diarrhea. Hence, diarrhea induced by enteral feeding should improve with the use of a bile acid binding agent, such as Colestid Granules. METHODS: We evaluated the effect of Colestid on enteral feeding-induced diarrhea in a double-blind placebo-controlled study. Nineteen patients who were nil per os (NPO) for 5 days before initiation of enteral feeding were enrolled in the study and treatment continued for 7 days. The severity and frequency of diarrhea were quantified. Fecal bile acids were measured enzymatically. Stool nutrient loss was measured by fat extraction, microkjeldahl determination of nitrogen, and bomb calorimetry of dried fecal specimens. RESULTS: Enteral feeding resulted in a high frequency of diarrhea (95%) at some time during the observation period. The majority of episodes of diarrhea in both groups were of low volume. Colestid significantly decreased the prevalence and severity of diarrhea. Colestid had no significant effect on fecal calorie or nutrient losses. The average bile acid concentration in the stool increased significantly after enteral feeding. CONCLUSION: Enteral feeding-induced diarrhea is, at least in part, due to malabsorption of bile acids. The bile acid resin binding agent Colestid improves diarrhea induced by enteral feeding.

Aged↗
PubMed1997

Plasma (carotenoids, retinol, alpha-tocopherol) and tissue (carotenoids) levels after supplementation with beta-carotene in subjects with precancerous and cancerous lesions of sigmoid colon.

OBJECTIVES: (1) To compare tissue and plasma carotenoids status of healthy subjects and subjects with pre-cancer and cancer lesions; (2) to evaluate the effect of beta-carotene supplementation on the concentrations of other carotenoids in tissue (luteine + zeaxanthin, cryptoxanthin, lycopene, alpha-carotene) and in plasma and also retinol and alpha-tocopherol levels. DESIGN: Eighteen subjects were divided into three groups on the basis of colonoscopy and histological analytical findings: four healthy subjects (control group A); seven subjects affected by adenomatous polyps (group B with pre-cancer lesions); seven subjects suffering from colonic cancer (group C). Blood and colonic biopsy samples were taken (of colon and rectal mucosa) before and after beta-carotene supplementation in all subjects. Groups A and B received a daily dose of beta-carotene (30 mg/die) for 43 d. Group C's supplementation was terminated at the time which was performed, usually within 15 d. The tissue and plasma concentration of carotenoids, retinol and alpha-tocopherol were determined by high-performance liquid chromatography. RESULTS: The tissue concentrations of each carotenoid were similar in all the intestinal sites examined as regards groups A and B, although there was a high degree of intra individual variability within each group. Only beta-carotene made significant increases (P < 0.001) after supplementation. The subjects with cancer show tissue levels for each carotenoid lower than those of healthy subjects or subjects with polypous. The plasma levels of alpha-tocopherol did not change after supplementation while significant increases were noted of retinol, alpha-carotene (P < 0.01) and of beta-carotene (P < 0.001). CONCLUSIONS: The patients with colonic cancer seemed to undergo a significant reduction in their antioxidant reserves with respect to the normal subjects and or polyps. We can confirm that oral B-carotene supplementation induces also an increase in plasma alpha-carotene in all groups.

Adenomatous Polyposis Coli↗
PubMed1997

Expression of c-myc in human colonic tissue in response to beta-carotene supplementation.

Dietary supplementation with beta-carotene at 30 mg/day results in an increased serum trans-retinoic acid concentration in patients with a prior colonic polyp. In a number of human cell lines, trans-retinoic acid upregulates c-myc mRNA expression in colonic mucosa by reverse transcription polymerase chain reaction and correlated the results with serum concentrations of all-trans- (ATRA), 13-cis-(13-cRA), and total retinoic acid. Serum and colonic biopsy samples were obtained before and 90 days after administration of a placebo (n = 7) or 30 mg of beta-carotene (n = 5) daily. An increase in c-myc expression after supplementation was observed in 6 of 12 subjects, but 5 of these 6 subjects had decreased total serum retinoic acid concentration and 4 had decreased ATRA concentration. In addition, five of the six subjects with increased c-myc expression had received a placebo. Conversely, c-myc expression was increased in only two of five paired samples from subjects whose total serum retinoic acid concentration increased during the 90-day supplementation period. We conclude that c-myc expression is not correlated with ATRA, 13-cRA, or total retinoic acid concentration in vivo and that increased serum retinoic acid secondary to increased tissue beta-carotene is not sufficient to activate c-myc transcription.

Aged↗
PubMed1997

Immunomodulatory effect of beta-carotene on T lymphocyte subsets in patients with resected colonic polyps and cancer.

Results from a number of studies suggest that beta-carotene-containing foods prevent the initiation or progression of various cancers. One possible mechanism for this effect could be enhancement of the immune response. The aim of this study was to determine whether beta-carotene modulates T lymphocyte subsets in patients affected with colonic polyps or cancerous lesions. Patients with previous adenomatous colonic polyps (n = 18) or colon cancers (n = 19) were randomized to receive placebo or beta-carotene (30 mg/day) for three months. Percentages of T lymphocyte subsets were determined using flow cytometry in blood samples collected before randomization and at three months. T lymphocyte subsets of 14 normal control subjects were also determined for comparison. Initially, there was no difference in total leukocyte counts, percentage of lymphocytes, and various subsets of lymphocytes among the three groups, although in cancer patients there was a lower percentage of CD4 and interleukin-2 (IL-2) receptor-positive (IL-2R+) cells than in patients with polyps and in controls. After supplementation with beta-carotene, a significant increase in IL-2R+ T lymphocytes (from 12.7 +/- 3.0% to 26.0 +/- 1.9%) and CD4+ lymphocytes (from 40.9 +/- 3.1% to 45.6 +/- 3.2%) was seen only in the cancer patients. These percentages remained unchanged in patients with adenomatous polyps receiving placebo or beta-carotene. We concluded that beta-carotene increased the number of IL-2R+ T lymphocytes and CD4+ lymphocytes, which in turn may produce IL-2 only in patients with cancer who may already have some deficiency in their immune system. This increase in activated T lymphocytes may mediate cytotoxic reactions to cancer cells via cytokine production.

Adult↗
PubMed1997

Three cases of comprehensive dietary therapy and pharmacotherapy of patients with complex obesity-related diseases.

The effect of weight loss with anorectic medications on sleep apnea, non-insulin-dependent diabetes, and steatohepatitis is illustrated in three cases from practice in a clinical nutrition setting. Prevention of obesity, a chronic disorder, is preferable, but when obesity becomes a major obstacle in the care of patients with respiratory, cardiovascular, and metabolic disorders and osteoarthritis, an intense course of weight reduction using anorectic medications under medical and dietetic guidance is essential for patients' survival and reduction of medical cost.

Adult↗
PubMed1997

Effect of aspirin on prostaglandin E2 and leukotriene B4 production in human colonic mucosa from cancer patients.

Results from epidemiological studies indicate that chronic administration of aspirin reduces the incidence of colon cancer. The mechanism that accounts for this reduction is not known, but it may be related to the decreased production of prostanoids that results from aspirin inhibition of cyclooxygenase. However, it is not known whether aspirin has a local effect on prostanoid production in the colonic mucosa and whether this effect is dose dependent. In this study, we determined the effect of oral administration of aspirin on the production of the prostanoid prostaglandin E2 (PGE2) in the intact human colonic mucosa. Inhibition of cyclooxygenase could result in an increased availability of arachidonic acid and a corresponding increase in production of other eicosanoids. To determine whether such an effect occurs, we also quantitated the concentration of leukotriene B4 (LTB4) in colonic mucosal samples. Mucosal samples were obtained during sigmoidoscopy from the colons of 17 subjects with a history of colonic cancer prior to and following 60 days of self-administration of 325 mg aspirin/day and again 60 days after administration of 650 mg aspirin/day. PGE2 and LTB4 concentrations were determined by enzyme immunoassay for tissue samples that were flash frozen after removal from the biopsy forceps and also in medium that was collected from tissue samples that were incubated for 4 h following removal from the subject. PGE2 concentrations were decreased significantly in samples collected after 60 days of consumption of 325 mg aspirin. An additional 60 days of consuming 650 mg aspirin/day did not result in a further significant decrease relative to that attained after consumption of 325 mg/day. Similar results were obtained using colonic explants, and the addition of aspirin to medium further reduced PGE2 production. LTB4 in tissue and medium was not significantly different in pre-versus post-aspirin samples, with the exception of an increased concentration in medium samples collected after consumption of 650 mg/day relative to pre-aspirin samples. The results indicate that aspirin affects eicosanoid production in the colonic mucosa of humans, but the effect is most likely restricted to products of the cyclooxygenase-dependent pathway. It appears that 325 mg of aspirin is sufficient to affect PGE2 production and that increasing the dosage to 650 mg daily provides an additional decrease in PGE2 synthesis. However, the higher dosage was associated with a considerable increase in complaints of gastric discomfort. Additional study is needed to establish whether doses less than 325 mg also provide a significant decrease in PGE2 production.

Adult↗
PubMed1996

Cytotoxic effect of beta-carotene in vitro is dependent on serum concentration and source.

In a previous study we reported that beta-carotene solubilized in tetrahydrofuran (THF) is toxic for human colonic tumor cells in vitro using media containing 10% fetal calf serum (FCS). Cytotoxicity was evident using beta-carotene concentrations that are achieved in human serum as a result of supplementation with 30 mg beta-carotene/day. In an attempt to determine the mechanism for this toxicity we investigated the effect of beta-carotene when present in human serum as a result of dietary supplementation. This effect was compared to that observed for cells incubated in THF-solubilized beta-carotene. The results indicate that human serum from subjects with a high concentration of beta-carotene is not cytotoxic. Subsequent analysis revealed that in contrast to the results using FCS, THF-solubilized beta-carotene is not cytotoxic in the presence of human serum. In addition, the effect observed with FCS is blunted with increasing FCS concentration from > or = 90% cytotoxicity using 10% FCS to 36% using 100% FCS. The difference in results obtained using FCS and human serum may be due to a serum component that is relatively lacking in FCS as compared to human serum.

Antineoplastic Agents↗
PubMed1996

Gastric emptying, pulmonary function, gas exchange, and respiratory quotient after feeding a moderate versus high fat enteral formula meal in chronic obstructive pulmonary disease patients.

High fat enteral formulas have been advocated for the nutritional support of chronic obstructive pulmonary disease (COPD) patients because dietary fat utilization under ideal conditions produces less CO2 per O2 consumed than carbohydrate. No data exist for these patients comparing the effects of a moderate fat vs. a high fat enteral formula on gastric emptying times (GE) and subsequent CO2 production (VCO2), oxygen consumption (VO2), respiratory quotient (RQ), and pulmonary function. Our double-blind crossover study compared these parameters after feeding a 355 mL (530 kcal) meal with either 41% fat calories (Respalor) or 55% fat calories (Pulmocare). Thirty-six COPD outpatients with a forced expiratory volume in 1 s (FEV1) < 60% of predicted were studied after an overnight fast. Gastric emptying half-time (GE t1/2) was measured using the 99MTc-radionuclide technique; VCO2, VO2, RQ, and other pulmonary functions were measured at 0, 30, 90, and 150 min postprandial using the Canopy Mode of the Deltatrac Metabolic Monitor and the Renaissance Spirometry System. We observed a significantly (p = 0.0001) longer GE t1/2 of the high fat meal when compared to the moderate fat meal (134.1 vs. 108.6 min) At 30 and 90, but not at 150 min postprandial, the VCO2 and VO2 for patients fed the moderate-fat formula were significantly (p = 0.05) higher than for those fed the high-fat formula; no differences were observed for the other pulmonary functions. Although RQ increased significantly (p = 0.01) after both meals, no differences between formulas were noted at all postprandial times tested. Compared to the high-fat meal, the moderate-fat meal significantly enhanced gastric emptying. The earlier rise in VCO2 and VO2 after the moderate-fat meal did not impact pulmonary function and reflected the earlier utilization of the moderate-fat meal. The fact that RQ was not different between the two meals at all postprandial times tested suggest that the higher rise in VCO2 and VO2 after the moderate-fat meal was most likely due to earlier gastric emptying of the moderate-fat meal rather than the difference of the fat-to-carbohydrate ratio between the two tested meals. The impact of these findings on long-term management of COPD patients awaits long-term prospective studies.

Adult↗
PubMed1996

In vitro beta-carotene toxicity for human colon cancer cells.

Experiments were conducted to determine the effect of beta-carotene on human colon cancer cells in vitro. beta-Carotene solubilized in tetrahydrofuran (THF) was determined to be cytotoxic for three different cell lines: LS 180, SW 620, and HCT-15. The number of LS 180 and SW 620 cells surviving treatment with 2.9 microM beta-carotene was significantly reduced relative to THF-treated cells, and a similar reduction was achieved in HCT-15 cells with use of 5.8 microM beta-carotene. These concentrations are in the range achieved in serum of individuals supplemented with beta-carotene at 30 mg/day. There was no beta-carotene cytotoxicity in the concentration range that characterizes serum of unsupplemented individuals. Vitamin E at > 200 microM was not cytotoxic and at higher concentrations slightly stimulated proliferation of all three cell lines. Exposure of cells to vitamin E did not diminish the cytotoxicity of beta-carotene, suggesting that the toxic effect of beta-carotene is not due to prooxidant activity. Percent cytotoxicity was increased by extending the duration of exposure of cells to beta-carotene. Interestingly, beta-carotene cytotoxicity decreased with increasing cell density. This density-dependent toxicity was attributable to a higher beta-carotene concentration per cell for cells plated at lower densities. Thus toxicity of beta-carotene for colon cancer cells is dose, time, and cell density dependent and occurs in vitro at concentrations that can be achieved safely in humans.

Cell Division↗