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The role of the essential nutrients, vitamins A, B (complex), C and E and iron, as prophylactic as well as supportive therapy in experimental visceral leishmaniasis (VL), was studied in hamsters. Prophylactic administration of vitamin C (50, 100 and 250 mg/kg) from day 15 to day 0 (15 doses) significantly reduced the intake of Leishmania donovani in hamsters but had no therapeutic effect. In contrast, vitamins A, B complex and E and iron, whether used prophylactically or therapeutically, promoted parasite multiplication. The efficacy of sodium stibogluconate, a reference antileishmanial drug, was appreciably improved in animals administered prophylactically with vitamin C. However, supplementation of vitamin C during established infections resulted in reduced drug action. The results show that the prophylactic use of vitamin C may prevent the onset of leishmania infection and cautions against the indiscriminate use of nutrient supplements such as vitamin A, B complex, and E and iron in VL endemic areas.
During the past 10 to 20 years it has become increasingly clear that a certain number of drugs may lead to increased vitamin requirements. However, it is unusual for symptomatic avitaminosis to develop, and then only when circumstances are present which in themselves increase the risk of vitamin deficiency. Therapeutic doses of drugs will interfere with the vitamin status only to a restricted degree, provided they are administered for brief periods and to patients receiving a normal supply of vitamins. Most cases of vitamin deficiency have in fact been described in connection with drugs usually taken for a longer period of time by patients who were already in negative vitamin balance as a result of disease or marginal supply of the necessary vitamins. This review describes some of the more important articles covering this topic.
Multipotent self-renewing stem cell lines have been established using peripheral blood mononuclear cells from adult green fluorescent protein transgenic swine. These cells proliferate as nonadherent spheroids in primordial-specific culture media and readily differentiate into angiogenic, osteogenic, adipogenic, and neurogenic phenotypes when cultured under the appropriate conditions. These cells are designated peripheral blood-derived multipotent adult progenitor cells (PBD-MAPCs). When differentiated in endothelial-specific media, these cells exhibit a cobblestone morphology and express von Willebrand factor (vWF), take up 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarboxyanine-labeled acetylated low-density lipoprotein DiI-Ac-LDL, and form tubes with lumens when grown on pads of Matrigel. Under different culture conditions, the cells appear whorl-like in appearance and express alpha-actin, indicative of smooth muscle phenotype. In the presence of dexamethasone and ascorbic acid, PBD-MAPCs differentiate into cells that produce Alizarin Red-staining extracellular mineral, consistent with an osteogenic potential. Under different conditions the cells produce Oil Red O-staining lipid vacuoles, suggestive of an adipocyte phenotype. We have also developed conditions that induce PBDMAPCs to differentiate into neural cells, confirmed by the expression of specific neuron- and glial-specific markers. Upon transplantation into rat brain, the neurogenic cells survive and migrate throughout the striatum and corpus callosum. The cells remain brightly fluorescent throughout their time in culture, during in vitro differentiation, and after in vivo transplantation. PBD-MAPCs have been maintained in primordial cell media for more than 100 doublings, yet can be induced to differentiate rapidly and efficiently into distinct cell types. PBD-MAPCs are ideal tools to study the mechanisms of differentiation and may be superior to embryonic stem cells as cellular therapeutics.
Essential hypertension is associated with impaired endothelium-dependent vasodilation caused by oxygen free radical-induced nitric oxide (NO) breakdown. Because calcium antagonists can improve endothelial function in patients with essential hypertension, in this study we tested the hypothesis that this beneficial effect could be related to restoration of NO availability by antioxidant properties. In 15 healthy subjects and 15 hypertensive patients, we studied forearm blood flow (strain-gauge plethysmography) modifications induced by intrabrachial acetylcholine (ACh; 0.15, 0.45, 1.5, 4.5, and 15 microg/100 mL per minute), an endothelium-dependent vasodilator in basal conditions, during infusion of N:(G)-monomethyl-L-arginine (L-NMMA, 100 microg/100 mL forearm tissue per minute), an NO-synthase inhibitor, vitamin C (8 mg/100 mL forearm tissue per minute), and finally, simultaneous infusion of L-NMMA and vitamin C. The response to sodium nitroprusside (SNP; 1, 2, and 4 microg/100 mL forearm tissue per minute) was also evaluated. In control subjects, vasodilation to ACh was inhibited by L-NMMA and not changed by vitamin C. In hypertensive patients, vasodilation to ACh was blunted as compared with control subjects and resistant to L-NMMA. Vitamin C, which decreased plasma isoprostanes and increased plasma antioxidant capacity, increased the response to ACh and restored the inhibiting effect of L-NMMA. In hypertensive patients, the study was repeated after 3-month treatment with nifedipine gastrointestinal therapeutic system (30 to 60 mg/daily). Nifedipine treatment decreased circulating plasma lipoperoxides and isoprostanes and increased plasma antioxidant capacity. Moreover, nifedipine increased the vasodilation to ACh but not to SNP and restored the inhibiting effect of L-NMMA on ACh-induced vasodilation, whereas vitamin C no longer exerted its facilitating activity. These results indicate that nifedipine increases endothelium-dependent vasodilation by restoring NO availability, an effect probably determined by antioxidant activity.
Between December 1972 and February 1973, 2349 volunteers participated in a double-blind trial to assess the effect of large doses of vitamin C on the incidence and severity of winter illness. In addition, records were kept but no tablets taken during March. Subjects were randomly allocated to eight treatment regimens: three prophylactic-only (daily dose 0.25, 1 or 2 g), two therapeutic-only (4 or 8 g on the first day of illness), one combination (1 g daily and 4 g on the first day of illness), and two all-placebo. None of the groups receiving vitamin C showed a difference in sickness experience that was statistically significant from that of the placebo groups, but the results obtained were compatible with an effect of small magnitude from both the prophylactic and therapeutic regimens, and an effect of somewhat greater magnitude from the combination regimen. The combination regimen was associated more with a reduction in severity than frequency of illness, although the extra dosage was limited to the first day of illness. In spite of the eightfold range in daily dose, the three prophylactic-only regimens showed no evidence of a dose-related effect, but the 8 g therapeutic dose was associated with less illness than the 4 g therapeutic dose. There was no evidence of side effects from the 1 and 2 g prophylactic doses of vitamin C, and no evidence of a rebound increase in illness during the month following withdrawal of the daily vitamin supplements. On the basis of this and other studies it is suggested that the optimum daily dose of vitamin C is less than 250 mg, except possibly at the time of acute illness, when a larger daily intake may be beneficial.
Antiaggregative effect of aspirin has been studied in white rats that were given vitamins A, E, C and P in balanced diet in doses adequate to therapeutic ones. Aspirin (15 mg/100 g of body weight) without additional vitamin dose inhibits spontaneous and ADP-induced aggregation to 50% within 3 days following its administration restricting release of thrombocytic factors 3 and 4 into plasma, maximal aggregation, maximal reaction time and aggregation rate decreasing. Antiaggregative effect of aspirin is intensified with additional vitamins administration since the 4th day: aggregation inhibition lasting 5 days is noted in a dose of 5 mg/100 g of weight; antiaggregative effect of 10 mg dose of aspirin in combination with vitamin is higher than that of aspirin in a dose of 15 mg/100 g in animals without additional vitamin administration. Vitamins intensify antiaggregative effect of aspirin, prolongate its activity, increase hypocoaguloemia due to reduced releasing of thrombocytic factors 3 and 4 into plasma. Anticoagulative effect of vitamin combination examined is insufficient, however it potentiates aspirin antiaggregative effect. It is expedient to study vitamin combination influence on treating the diseases when thrombocyte aggregative activity increase does not take effect on pathologic process. So, administration of vitamin combination studied is likely to diminish thrombocyte aggregative activity to a level needed using lower aspirin doses.
Nutritional antioxidants support prostacyclin synthesis by preventing lipid hydroperoxide-mediated inhibition of prostacyclin synthetase. Recent preliminary clinical studies indicate that supplementary antioxidants exert antithrombotic effects in vivo that are most likely attributable to enhanced prostacyclin production. Optimal antioxidant nutrition may thus have preventive and therapeutic value for disorders in which inappropriate platelet aggregation plays an etiologic role, including MI, stroke, atherogenesis, pre-eclampsia, and the vascular complications of diabetes. In light of evidence that platelet aggregation encourages the implantation of hematogenous tumor metastases, supplemental antioxidants should also impede tumor dissemination--an effect which will be complemented by the immunostimulant actions of these nutrients. By exerting anticarcinogenic, immunostimulant and anti-metastatic effects, nutritional antioxidants should act to inhibit neoplasia at each stage of its development.
Exogenous n-3 polyunsaturated fatty acids (PUFA) and specially docosahexaenoic acid (DHA) have been previously reported to potentiate the efficacy of anticancer agents that generate an oxidative stress, such as anthracyclines, by enhancing the susceptibility of cell membranes to lipid peroxidation. Since lipid peroxidation has also been suggested to mediate anthracycline-induced heart failure, we designed a study aimed at investigating whether a DHA-enriched diet coupled with controlled oxidative conditions prevents or aggravates this serious side effect in vivo. Female Sprague-Dawley rats were submitted for at least 3 weeks to diet enriched in DHA, which was provided either as natural oil (sardine oil, experiment 1) or in a purified form (DHASCO, experiment 2). At the same time, to constrain the nutritional oxidative status, the anti-oxidant Vitamin E or the pro-oxidant menadione/sodium ascorbate redox mixture was added. Then, epirubicin was administered weekly at two cumulative doses, 9 mg x kg(-1) (experiment 1) or 15 mg x kg(-1) (experiment 2). Cardiotoxicity was assessed by electrocardiographic (ECG) and hemodynamic measurements, completed with histological examination. Epirubicin-induced dose-dependent mortality, alterations of hemodynamic parameters and histological damages, all features characterizing the occurrence of congestive heart failure. Moreover, the addition of anti- or pro-oxidant did not change the hemodynamics either at the lowest (experiment 1) or the highest dose (experiment 2). Similarly, the ECG measurements and histological examinations did not reveal any difference. DHA was actually incorporated, as evaluated through the adipose tissue fatty acid composition. All these observations indicated that the DHA-enriched diet, placed under controlled oxidative conditions, did not appear to prevent but neither to aggravate epirubicin-induced cardiotoxicity. These findings support the idea that DHA improves the anthracycline therapeutic index.
Our group recently observed that manganese prevents oxidative brain injury in the iron-induced parkinsonian animal model. It has also been suggested that manganese retards while copper promotes the development of atherosclerosis. In this report, we provide further evidence to support a controversial notion that manganese is an atypical antioxidant. Among transition metals, Cu2+ and Fe2+ (0.1 to 125 microM), but not Mn2+, converted hydrogen peroxide to reactive hydroxyl radicals via the Fenton reaction at pH 7.4. Iron's pro-oxidative rate is relatively slow, but it is accelerated further by ascorbate (50 microM) in 37 degrees C Dulbecco's phosphate buffered saline. Moreover, Mn2+ (0-80 microM) concentration dependently retarded diene conjugation of human low density lipoproteins stimulated by 5 microM Cu2+. This new result is consistent with our recent finding that Mn2+ (0 to 20 microM) does not initiate brain lipid peroxidation while it inhibits iron-induced peroxidation of polyunsaturated fatty acids. These unexpected manganese results are somewhat at odds with a prominent theory that manganese is a prooxidative transition metal. Furthermore, iron and copper induced free radical generation and lipid peroxidation are suppressed by lowering the incubation temperature; this suggests that hypothermia may decrease the oxidative stress and damage in vivo. In conclusion, normal dietary intake of manganese may protect cells and neurons from oxidant stress through the inhibition of propagation of lipid peroxidation caused by hydroxyl radicals generated by pro-oxidative transition metals such as iron and copper. Potential therapeutical uses of manganese, manganese SOD mimetics and hypothermia for protecting brain neurons and vascular endothelial cells against oxidative stress and damage have been successfully demonstrated in both animal models and clinical trials.
The objective of this study was to assess the therapeutic advantage of glutathione ester along with cisplatin. Comparisons were made with renal reduced glutathione, enzymatic antioxidants, and lipid peroxidation levels. Cisplatin caused differential toxic effects on renal antioxidants and lipid peroxidation. However administration of glutathione ester modulates the toxic effects of cisplatin observed in renal antioxidants and lipid peroxidation. The finding that glutathione ester co-administration along with cisplatin is more effective and advantageous in protecting against the nephrotoxicity of cisplatin when it was given alone.
The large majority of N-nitroso compounds (NOC) have been found to produce genotoxic effects and to cause tumor development in laboratory animals; four NOC have been classified by the International Agency for Research on Cancer (IARC) as probably and another 15 as possibly carcinogenic to humans. A considerable fraction of drugs are theoretically nitrosatable due to the presence of amine, amide or other groups which by reacting with nitrite in the gastric environment, or even in other sites, can give rise to the formation of NOC, and in some cases other reactive species. This review provides a synthesis of information on the chemistry of NOC formation, the carcinogenic activity of NOC in animals and humans and the inhibitors of nitrosation reactions. It contains information on the drugs which have been tested for the formation of NOC by reaction with nitrite and the genotoxic-carcinogenic effects of their nitrosation products. In an extensive search we have found that 182 drugs, representing a wide variety of chemical structures and therapeutic activities, were examined in various experimental conditions for their ability to react with nitrite, and 173 (95%) of them were found to form NOC or other reactive species. Moreover, 136 drugs were examined in short-term genotoxicity tests and/or in long-term carcinogenesis assays, either in combination with nitrite or using their nitrosation product, in order to establish whether they produce genotoxic and carcinogenic effects; 112 (82.4%) of them have been found to give at least one positive response. The problem of endogenous drug nitrosation is largely unrecognized. Only a small fraction of theoretically nitrosatable drugs have been examined for the possible formation of genotoxic-carcinogenic NOC, guidelines for genotoxicity testing of pharmaceuticals do not indicate the need of performing the appropriate tests, and patients are not informed that the drug-nitrite interaction and the consequent risk can be reduced to a large extent by consuming the nitrosatable drug with ascorbic acid.
Pharmaceutic studies were carried out with a total of 89 cows affected with chronic endometritis, following up the biopharmacokinetic and therapeutic effect of amopen foaming tablets that contained amoxicillin trihydrate at the rate of 30,000 and 45,000 IU. Andreev's catheter was used to introduce the tablets into the uterus. It was found that the use of 600,000 IU amoxicillin developed therapeutic concentrations within the uterus up to the 48 h-72nd hour. Amoxicillin persisted in the blood serum up to the sixth hour. It was not eliminated by milk. The therapeutic effect with such cows (in which the causative organisms were susceptible to amoxicillin) to which the amopen tablets were introduced into the uterus (14 t. x 630,000 IU) three to four times at 48-hour intervals was shown to be 76 per cent. The use of 5 tablets of 45,000 IU at the 24th hour after the last insemination of cows that failed to conceive, exhibiting no symptoms of inflammation, raised the conception rate by 24.1 per cent.
Treatment of mice bearing P388 lymphocytic leukemia with combined hydroxocobalamin (0.1 mmol/kg) and sodium ascorbate (1.0 mmol/kg) for 10 consecutive days resulted in 70% increase in survival. Treatment with dehydroascorbate (1.0 mmol/kg) similarly increased survival. The extended treatment for 15 days posttumor inoculation failed to improve survival as did lowering the tumor inocula from 10(6) to 10(4) cells in similarly treated mice. P388 cells in primary culture with cystine as a source of cysteine require exogenous thiols or disulfides for growth and also grow with cysteine but only when trace copper is sequestered with bathocuproine sulfonate. This is due to the copper catalyzed oxidation of cysteine to cystine, which these cells cannot utilize. Cells grew in medium preincubated for 8 h with cysteine and bathocuproine sulfonate, but lysed when the preincubated medium included hydroxocobalamin (10 microM) and sodium ascorbate (100 microM). This defect was corrected by resupplementation with cysteine or cystine plus bishydroxyethyl disulfide after addition of the cells. Further support for cysteine depletion as a factor in therapy is obtained by therapeutic interference with 4-thiamethionine (25 mumol/kg). This mixed disulfide of cysteine and methyl mercaptan enters cells as a methionine analogue, is reduced to supply cysteine, and thus withstands the oxidative environment that limits the utilization of cysteine as a nutrient. These results suggest that dehydroascorbate is generated from combined hydroxocobalamin and ascorbate and accounts for the thiol-prive activity of combined hydroxocobalamin and ascorbate therapy. The ultimate failure of therapy by thiol oxidation may be due to the increased availability of cysteine produced by host tissues, possibly infiltrating macrophages, that occurs independently of extended treatment and the size of the tumor inoculum.
BACKGROUND AND OBJECTIVE: Cardiovascular diseases are associated with the ischemia/reperfusion phenomena and therefore to the oxidation/antioxidation balance. The aim of this study was to determine malondialdehyde, nitric oxide, glutathione, ascorbic and dehydroascorbic acid in patients with chronic ischemic heart disease. PATIENTS AND METHOD: 32 male patients, with chronic ischemic heart disease, between 40 and 60 years of age were studied. These individuals were divided in two groups: 16 with hypertension and 16 without hypertension. Both groups were compared with 31 healthy male subjects (control group). RESULTS: Significant differences (p < 0.001) was observed in malondialdehyde between no-hypertension ischemic group: 5.3 (1.5) microM and the hypertension ischemic group: 4.8 (1.3) microM in contrast with the healthy group: 2.2 (0.5) microM. Hypertension ischemic group showed significant greater reduced glutation levels: 286.1 (31.4) microg/ml than control group 262.0 (38.8) microg/ml; p < 0.03 and no-hypertension ischemic group: 256.4 (41.5) microg/ml; p < 0.02. No significant difference in the rest of the parameters for all study groups. CONCLUSIONS: Oxidation/antioxidation balance during chronic ischemic heart disease can be considered as a good metabolic ischemia indicator, that used in the monitoring and therapeutic evaluation could detect molecular changes that anticipate installation of tissue damage.
The objective of this study was to evaluate the influence of ingested l-arginine, l-citrulline, and antioxidants (vitamins C and E) on the progression of atherosclerosis in rabbits fed a high-cholesterol diet. The fatty diet caused a marked impairment of endothelium-dependent vasorelaxation in isolated thoracic aorta and blood flow in rabbit ear artery in vivo, the development of atheromatous lesions and increased superoxide anion production in thoracic aorta, and increased oxidation-sensitive gene expression [Elk-1 and phosphorylated cAMP response element-binding protein]. Rabbits were treated orally for 12 weeks with l-arginine, l-citrulline, and/or antioxidants. l-arginine plus l-citrulline, either alone or in combination with antioxidants, caused a marked improvement in endothelium-dependent vasorelaxation and blood flow, dramatic regression in atheromatous lesions, and decrease in superoxide production and oxidation-sensitive gene expression. These therapeutic effects were associated with concomitant increases in aortic endothelial NO synthase expression and plasma NO(2)(-)+NO(3)(-) and cGMP levels. These observations indicate that ingestion of certain NO-boosting substances, including l-arginine, l-citrulline, and antioxidants, can abrogate the state of oxidative stress and reverse the progression of atherosclerosis. This approach may have clinical utility in the treatment of atherosclerosis in humans.
PURPOSE: To review prospective epidemiologic studies and randomized trials regarding the role of antioxidant vitamins (vitamins E and C and beta-carotene) in the prevention of cardiovascular disease, with emphasis on differences in results obtained by these two types of studies. DATA SOURCES: Computerized and manual searches of the literature on antioxidant vitamins and cardiovascular disease. STUDY SELECTION: Prospective epidemiologic studies and randomized trials that included 100 or more participants and provided quantified estimates of antioxidant vitamin intake. DATA SYNTHESIS: Comparisons of relative risk reductions (RRR) across observational studies and randomized trials, including assessment of dose-response relations. RESULTS: All three large epidemiologic cohort studies of vitamin E noted that high-level vitamin E intake or supplementation was associated with a significant reduction in cardiovascular disease (RRR range, 31% to 65%), as measured by various fatal and nonfatal cardiovascular end points. To obtain these reductions, vitamin E supplementation must last at least 2 years. Less consistent reductions were seen in studies of beta-carotene (RRR range, -2% to 46%) and vitamin C (RRR range, -25% to 51%). Considerable biases in observational studies, such as different health behaviors of persons using antioxidants, may account for the observed benefit. By contrast, none of the completed randomized trials showed any clear reduction in cardiovascular disease with vitamin E, vitamin C, or beta-carotene supplementation. The trials were not specifically designed to assess cardiovascular disease, did not provide data on nonfatal cardiovascular end points, may have had insufficient treatment durations, and used suboptimal vitamin E doses. The completed trials were of adequate size to indicate that the true therapeutic benefit of vitamin E and other antioxidants in reducing fatal cardiovascular disease (a survival benefit as long as 5 years) is probably more modest than the epidemiologic data suggest. CONCLUSION: The epidemiologic data suggest that antioxidant vitamins reduce cardiovascular disease, with the clearest effect for vitamin E; however, completed randomized trials do not support this finding. Much of this controversy should be resolved by the ongoing large-scale and long-term randomized trials designed specifically to evaluate effects on cardiovascular disease.
OBJECTIVE: To determine the possible role of oxidants and antioxidants in the pathogenesis of chronic tonsillitis (CT) and adenoid hypertrophy (AH) in children. METHODS: Randomized, prospective, controlled. The study group was made up of children with chronic tonsillitis and adenoid hypertrophy who are to undergo tonsillectomy and adenoidectomy. The control group was constructed with otherwise healthy children with normal ENT examination. The blood levels of antioxidants (retinol, beta-carotene, alpha-tocopherol, laycopene, ascorbic acid, superoxide dismutase, glutathione peroxidase, GSH) and peroxidation products (malondialdehyde) were determined before and 1 month after the operation in the study group and once only in the control group. These antioxidants and peroxidation products were also measured in the tonsil and adenoid tissue that were obtained during operation. RESULTS: In the study group, the blood levels of antioxidants and oxidant before and after the operation were significantly different when compared to the control group (P < 0.05). In the study group, the blood antioxidant levels increased and oxidant level decreased significantly after the operation (P < 0.05). These levels after the operation never reached those of the control group. CONCLUSIONS: Oxidants and antioxidants played a significant role in the pathogenesis of chronic tonsillitis and adenoid hypertrophy in children. These children are under significant oxidative stress. Tonsillectomy and adenoidectomy significantly decreased the oxidative stress in these patients, but could not normalize it completely. Further studies are necessary to evaluate their possible therapeutic role in preventing recurrent tonsillitis and treating postoperative patients to help normalize their blood levels of antioxidants.