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At least 1,045 records · Page 58Linked to original sources
PubMed1993

Influence of beta carotene, vitamin E, and vitamin C on endogenous antioxidant defenses in erythrocytes.

OBJECTIVE: To evaluate the in vivo radical scavenger activity of vitamin E, vitamin C, and beta carotene on erythrocyte membranes. DESIGN: A prospective, open trial without placebo. SETTING: Department of Clinical Pharmacy. PATIENTS: Ten healthy volunteers being supplemented with beta carotene, vitamin E, and vitamin C. MEASUREMENTS: Erythrocytes were incubated in water bath with 2,2' azobis (2 amidinopropane) hydrochloride (AAPH). AAPH decomposes spontaneously at 37 degrees C to generate free radicals inducing membrane cellular damage and hemolysis. The absorbance was measured at 405 nm at 0, 30, and 60 min, and then every 20 minutes for four hours. The time for 50 percent of maximal hemolysis (T50%), which expresses the radical scavenger activity of erythrocytes, was determined. RESULTS: The physiologic T50% value determined in 52 healthy volunteers is 117 +/- 12 min. Patients receiving these supplements have a higher value of T50% (143.2 +/- 11.6 min at 30 d and 145.7 +/- 10.5 min at 60 d) than the physiologic value (p < 0.001). CONCLUSIONS: These data suggest that vitamin C, vitamin E, and beta carotene stimulate the radical scavenger activity of erythrocyte membranes after 30 days.

Amidines↗
PubMed2004

Pro-apoptotic mechanisms of action of a novel vitamin E analog (alpha-TEA) and a naturally occurring form of vitamin E (delta-tocotrienol) in MDA-MB-435 human breast cancer cells.

Vitamin E derivative, RRR-alpha-tocopheryl succinate (vitamin E succinate, VES), is a potent pro-apoptotic agent, inducing apoptosis by restoring both transforming growth factor-beta (TGF-beta) and Fas (CD95) apoptotic signaling pathways that contribute to the activation of c-Jun N-terminal kinase (JNK)-mediated apoptosis. Objectives of these studies were to characterize signaling events involved in the pro-apoptotic actions of a naturally occurring form of vitamin E, delta-tocotrienol, and a novel vitamin E analog, alpha-tocopherol ether acetic acid analog [alpha-TEA; 2,5,7,8-tetramethyl-2R-(4R,8R,12-trimethyltridecyl)chroman-6-yloxyacetic acid]. Like VES, alpha-TEA and delta-tocotrienol induced estrogen-nonresponsive MDA-MB-435 and estrogen-responsive MCF-7 human breast cancer cells to undergo high levels of apoptosis in a concentration- and time-dependent fashion. Like VES, the two compounds induced either no or lower levels of apoptosis in normal human mammary epithelial cells and immortalized but nontumorigenic human MCF-10A cells. The pro-apoptotic mechanisms triggered by the structurally distinct alpha-TEA and delta-tocotrienol were identical to those previously reported for VES, that is, alpha-TEA- and delta-tocotrienol-induced apoptosis involved up-regulation of TGF-beta receptor II expression and TGF-beta-, Fas- and JNK-signaling pathways. These data provide a better understanding of the anticancer actions of a dietary form of vitamin E (delta-tocotrienol) and a novel nonhydrolyzable vitamin E analog (alpha-TEA).

Anticarcinogenic Agents↗
PubMed2001

Vitamin A antagonizes calcium response to vitamin D in man.

For unknown reasons, the highest incidence of osteoporosis is found in northern Europe. In these populations, the sunlight exposure is limited and the vitamin A intake is high. The interaction between vitamin A and D has been the subject of several in vitro and animal studies. We have studied the acute effects of vitamin A and D on calcium homeostasis in 9 healthy human subjects. We compared the effect of (i) 15 mg of retinyl palmitate, (ii) 2 microg of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], (iii) 15 mg of retinyl palmitate plus 2 microg of 1,25(OH)2D3, and (iv) placebo in a double-blind crossover study. The subjects took vitamin preparations at 10:00 p.m. and the following day blood samples were collected five times from 8:00 a.m. to 4:00 p.m. Serum levels of 1,25(OH)2D3 and retinyl esters increased (1.7-fold and 8.3-fold, respectively; p < 0.01). As expected, serum calcium (S-calcium) increased (2.3%; p < 0.01) and S-parathyroid hormone (PTH) decreased (-32%; p < 0.05) after 1,25(OH)2D3 intake. In contrast, retinyl palmitate intake resulted in a significant decrease in S-calcium when taken alone (-1.0%; p < 0.05) and diminished the calcium response to 1,25(OH)2D3 after the combined intake (1.4%; p < 0.01). S-PTH was unaffected by retinyl palmitate. No significant changes in serum levels of the degradation product of C-telopeptide of type I collagen (CrossLaps), or U-calcium/creatinine levels were found. In conclusion, an intake of vitamin A corresponding to about one serving of liver antagonizes the rapid intestinal calcium response to physiological levels of vitamin D in man.

Adult↗
PubMed1977

A comparative study of the effect of vitamin E-nicotinate and the combination of vitamin E and nicotinic acid on the hydrogen peroxide-induced platelet aggregation.

The inhibitory effect of vitamin E-nicotinate upon the hydrogen peroxide (H2O2)-induced platelet aggregation was found to be greater than that of either vitamin E alone or the combination of vitamin E and nicotinic acid. Nicotinic acid showed no inhibitory effect. It was suggested that the effect of vitamin E-nicotinate was not due to the additive effect of vitamin E and nicotinic acid produced by hydrolysis, but to the unique and distinctive property of vitamin E-nicotinate itself.

Adolescent↗
PubMed1994

Vitamin B12 metabolism and massive-dose methyl vitamin B12 therapy in Japanese patients with multiple sclerosis.

Serum vitamin B12 levels and unsaturated vitamin B12 binding capacities were measured in 24 patients with multiple sclerosis (MS), 73 patients with other neurological disorders and 21 healthy subjects. There was no decrease in the vitamin B12 levels, however, a significant decrease in the unsaturated vitamin B12 binding capacities was observed in patients with MS when compared with other groups. A massive dose of methyl vitamin B12 (60 mg every day for 6 months) was administered to 6 patients with chronic progressive MS, a disease which usually had a morbid prognosis and widespread demyelination in the central nervous system. Although the motor disability did not improve clinically, the abnormalities in both the visual and brainstem auditory evoked potentials improved more frequently during the therapy than in the pre-treatment period. We therefore consider that a massive dose methyl vitamin B12 therapy may be useful as an adjunct to immunosuppressive treatment for chronic progressive MS.

Adult↗
PubMed1996

New mechanisms of regulation of the genomic actions of vitamin D in bone cells: interaction of the vitamin D receptor with non-classical response elements and with the multifunctional protein, calreticulin.

Vitamin D exerts its genomic effects following binding to a specific receptor which is a member of the steroid hormone receptor superfamily. The vitamin D receptor (VDR) forms heterodimers with retinoid X receptors (RXRs) and the dimer then interacts with its cognate binding site, termed vitamin D response element (VDRE), to affect the transcription of target genes. Recent studies have identified novel sequence motifs for VDREs as well as novel protein-protein interactions involving the VDR. These will be reviewed with particular emphasis on the complex VDRE from the c-fos proto-oncogene promoter region and the inhibition of the vitamin D signal transduction pathway by the multifunctional protein, calreticulin. Thus research on the control of gene transcription by vitamin D reveals examples of molecular interplay between transcriptional regulatory pathways and provides new insight into the molecular mechanism of action of vitamin D.

Base Sequence↗
PubMed1986

Use of 1 alpha-hydroxyvitamin D3 to prevent bovine parturient paresis. VI. Concentrations of vitamin D metabolites and vitamin D3 equivalence in milk.

Concentration of vitamin D metabolites was determined in the milk of control and 1 alpha-hydroxyvitamin D3-injected (700 micrograms) cows that calved 36 to 43 h after treatment. Milk samples were taken 60 h after calving. Concentrations of vitamin D, 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D in milk of the control cows were 372 +/- 24, 264 +/- 68, 68 +/- 26, and 21 +/- 3 ng/L, respectively. Concentrations of vitamin D metabolites in the milk of the treated cows did not differ significantly from those of controls. Concentration of 1 alpha-hydroxyvitamin D3 in milk of treated cows was less than 20 ng/L. In a second experiment, cows were injected twice, at 72-h intervals, with 350 micrograms 1 alpha-hydroxyvitamin D3. Milk was taken 60 h after parturition from cows that calved 37 to 60 h after the second injection. The vitamin D3 equivalence of the milk was 40 +/- 3 IU/L. Results indicate that injection of 700 micrograms 1 alpha-hydroxyvitamin D3 did not affect the concentration of vitamin D metabolites or the vitamin D3 equivalence of milk taken 60 h after calving.

Animals↗
PubMed2001

Vitamin D receptor polymorphism and the risk of colorectal adenomas: evidence of interaction with dietary vitamin D and calcium.

Laboratory studies and epidemiological investigations suggest that vitamin D plays a role in the etiology of colorectal adenomas, possibly through a mechanism mediated by the vitamin D receptor (VDR). We conducted a clinic-based case-control study to examine the association between VDR polymorphisms and colorectal adenomas. We selectively identified a random subset of 393 cases of colorectal adenomas and 406 colonoscopy-negative controls from a clinic-based case-control study conducted in the metropolitan Minneapolis/St. Paul area during 1991-1994. A self-administered questionnaire was used to collect data on dietary and supplement intake of vitamin D and calcium, as well as on demographics, physical activity, medical information, lifestyle factors, reproductive history, and anthropometry. DNA was extracted from whole blood and assayed for the BsmI VDR polymorphism using an ABI 7700 TaqMan assay. Adjusted odds ratios (OR) and 95% confidence intervals (CIs) were evaluated using logistic regression. Compared with the bb genotype (33% of controls), neither the Bb (48.8% of controls) nor the BB (18.2% of controls) genotypes was strongly associated with risk of colorectal adenomas (OR = 0.86, CI = 0.63-1.19 and OR = 0.77, CI = 0.50-1.18, respectively). However, those with the lowest tertile of vitamin D intake and the BB genotype had a lower risk of colorectal adenoma (OR = 0.24, CI = 0.08-0.76) than those with the highest tertile of intake and the bb genotype. Similarly, those with the lowest tertile of calcium intake and the BB genotype had a reduced risk of colorectal adenoma (OR = 0.34, CI = 0.11-1.06). Although it has generally been shown that higher calcium and vitamin D intake are associated with a modestly reduced risk of colorectal neoplasia, our data suggest that those with the BB BsmI VDR genotype may be at reduced risk of colorectal adenoma in the presence of lower calcium and vitamin D intake.

Adenoma↗
PubMed2004

[The optimum amount of vitamin D for osteoporosis: in case of activated vitamin D treatment].

Since the resistance factors for the effect of vitamin D increases by aging, ingestion of various nutrition factors, such as calcium, and vitamin D is important for prevention and medical treatment of osteoporosis. 1 alpha 25-dihydroxyvitamin D(3) known as active form of vitamin D can stimulate calcium absorption from intestine and also it is used for the medical treatment of osteoporosis. The vitamin D action for the regulation of bone and mineral metabolism changes with the sufficiency states or the amounts of ingestion of vitamin D. Therefore, the action as a medicine is not simple. This article reviews the effect and its optimum ingestion amount of activated vitamin D in osteoporosis medical treatment.

Adult↗
PubMed2005

Two newborns with nutritional vitamin B12 deficiency: challenges in newborn screening for vitamin B12 deficiency.

Vitamin B12 deficiency causes decreased Methionine Synthase and L-Methylmalonyl-CoA Mutase activity and results in accumulation of Homocysteine, Methylmalonic acid and Propionylcarnitine. Propionylcarnitine is included in tandem mass spectrometry-based newborn screening programs for detection of certain inborn errors of metabolism. We report two asymptomatic newborns with Vitamin B12 deficiency due to maternal deficiencies. One was detected incidentally at 3 weeks of age; the second on supplemental newborn screening based on elevated Propionylcarnitine at 2 days of age. This illustrates the potential for false negative results for Vitamin B12 deficiency screening by acylcarnitine profiling in newborn screening. Homocysteine and Methylmalonic acid may be better markers of Vitamin B12 deficiency. In conclusion, we suggest measuring Methylmalonic acid, Propionylcarnitine and Homocysteine levels in blood spots in expanded newborn screening in order to detect asymptomatic newborns with Vitamin B12 deficiency. Further studies are needed to establish the sensitivity of these three markers in screening for Vitamin B12 deficiency.

Acyl-CoA Dehydrogenase, Long-Chain↗
PubMed2006

Cholesterol, cholesterol-lowering agents/statins, and urologic disease: Part IV--is vitamin E phosphate or another unique type of this vitamin the last chance for these supplements?

Vitamin E, once the highly espoused heart healthy paradigm of the dietary supplement world, has now been touted by many experts to be either heart unhealthy or simply ineffective based on the results of past and recent randomized trials in cardiovascular medicine. Natural and synthetic vitamin E supplements, especially in large dosages, have been the concern. Researchers have embarked on testing a variety of other novel forms of vitamin E, such as vitamin E phosphate and other forms of vitamin E, to determine safety issues as well as the impact on cardiovascular disease (CVD) risk markers and end-points. Until vitamin E demonstrates meaningful changes in some of the accepted markers of CVD prevention, it will be difficult to espouse their use specifically for these and other conditions.

Cardiovascular Diseases↗
PubMedDate not supplied

Direct in vitro effect of 1,25-dihydroxyvitamin D3 on islets insulin secretion in vitamin deficient rats: influence of vitamin D3 pretreatment.

Vitamin D3 deficiency decreased glucose-induced insulin release from isolated rat islets. In vivo, vitamin D3 treatment restored the B-cell response within 3 days; this delay suggests an effect of vitamin D3 metabolites. The effect of 1,25-dihydroxyvitamin D3 was studied in vitro on isolated islets from vitamin D3 deficient rats. When it was added to the incubation medium, it increased in a dose-dependent manner islet insulin secretion. However this effect only occurred when the vitamin D3-deficient rats received at least a single injection of vitamin D3 24 hours earlier; these results sustain the hypothesis of a direct but delayed in vitro stimulation of B cell function by 1,25-dihydroxyvitamin D3.

Animals↗
PubMedDate not supplied

[The effect of preventive vitamin supplementation on vitamin status and work productivity of conveyer belt workers in light industry].

The authors have studied the ways of correcting the vitamin status and influence of vitaminization on working capacity in workwomen in light industry. Prophylactic polyvitaminization (1 dragee of "Undevitum"/day, during 2 months) proved to produce positive effect on the vitamin status parameters (vitamin content in the blood and urine, clinical microsymptoms of vitamin deficiency), and on the dynamics of the physiological parameters of working capacity of workwomen at modern conveyer shoe making industry. It is recommended that persons suffering from chronic diseases influencing vitamin metabolism, first of all those over 45 years, should receive increased doses of prophylactic polyvitamins, thiamine and ascorbic acid, in particular.

Adult↗
PubMedDate not supplied

[Shortening diclofenac therapy by B vitamins. Results of a randomized double-blind study, diclofenac 50 mg versus diclofenac 50 mg plus B vitamins, in painful spinal diseases with degenerative changes].

The use of nonsteroidal anti-inflammatory drugs (NSAID) such as diclofenac for treatment of degenerative rheumatic disorders of the lumbar spine is of great significance in orthopedic practice. Clinical studies have shown that concomitant treatment with vitamins B1, B6, B12 and diclofenac provides more efficient pain relief than treatment using diclofenac alone. This study was undertaken in order to determine whether the duration of treatment with diclofenac for lower back pain can be shortened by adding B-vitamins to the therapeutic regimen. From September through December of 1986, 256 patients participated in a multicenter, controlled, randomized double-blind trial which compared the clinical efficacy of diclofenac (50 mg) with a combined therapy of diclofenac (50 mg) and vitamins B1, B6, and B12 (thiamine nitrate, pyridoxine hydrochloride, and cyanocobalamine, resp.; in dosages of 50 mg, 50 mg, and 0.25 mg, resp.). Patients were treated with 3 X 1 capsule daily for a maximum of two weeks, having the option to terminate participation in the trial after 1 week in the event of total pain relief. The data of 238 patients were able to be included in the evaluation. 29 patients opted to discontinue therapy due to remission on symptoms. Nineteen (65.6%) of these patients belonged to the combined therapy group, the other 10 (34.4%) having taken diclofenac alone; this difference is statistically significant (p less than 0.05). An important aspect in the evaluation of therapy was the patient response regarding the improvement of painful symptoms which, in addition to their subjective feedback, was reflected in the test results of the "Hoppe Pain Questionnaire (HPQ)." All parameters used as a measure of pain relief indicated superior results with the B-vitamin supplemented therapy when compared with results obtained with diclofenac alone. Moreover, after 3 days of therapy the "sensory" pain factor "sharpness" improved significantly. Undesirable side-effects were documented with 39 patients, 14 of them having discontinued therapy for this reason. No statistically significant difference could be determined within this group with regard to therapy. The study results document the positive influence of B-vitamins on painful symptoms and indicate that less NSAID is needed for pain relief when combined with B-vitamins.

Clinical Trials as Topic↗
PubMed1986

No tissue level abnormality of vitamin A concentration despite elevated serum vitamin A of uremic patients.

In 57 patients with chronic renal failure (CRF) [44 patients on regular dialysis treatment (RDT), 33 renal transplant patients (RT) and 26 normal patients (NP)] and in a further 11 patients with CRF (8 patients on RDT and 17 patients without any renal disease in the post mortem) the vitamin A content of the serum obtained from the tissue of the liver, the stomach, the subcutaneous adipose tissue and the bone were analyzed. The vitamin A content of the serum was increased significantly for all groups of patients in comparison with the control group, but hypervitaminotic ranges were not reached in any case. The vitamin A content decreased depending on the time of dialysis treatment and the period after kidney transplantation. The retinol-binding protein accumulated even more than vitamin A in CRF and RDT. This statement is not in conformity with that of a hypervitaminosis A, of which normal respectively decreased RBP levels are characteristic. The serum prealbumin concentration was near the upper limit of the normal range in all groups of patients. The serum content of beta-carotene in patients with CRF and RDT was raised in comparison with NP and RT patients. As to the vitamin A content of the organs, a distinctive decrease appeared in the liver, so that a marginal supply must be assumed. In the stomach and the subcutaneous adipose tissue no changes, in comparison with the control patients, resulted. Due to renal insufficiency the results indicated an unphysiological situation in the vitamin A metabolism. Connections with disturbances of the fat-household could not be set up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Cyclosporine administration decreases liver vitamin A stores in normal and vitamin A-deficient rats.

Thirty-four Wistar rats were fed a marginal or normal vitamin A diet and received daily for 14 days an intragastric intubation of oil supplemented with 0, 20, or 60 mg X kg-1 of cyclosporine A. The hepatic content and concentration of vitamin A were significantly decreased by cyclosporine treatment, whereas no modification occurred in kidney or serum vitamin A levels. No induction of hepatic cytochrome P-450 was observed in treated animals. These results suggest that cyclosporine interferes with vitamin A stores; thus, vitamin A supplementation may be useful in patients receiving cyclosporine therapy. Drug-metabolizing enzymes, which are cytochrome P-450 dependent, did not seem to be involved in the hepatic vitamin A decrease observed.

Animals↗
PubMed1984

Treatment with high-dose oral vitamin D2 in patients with jejunoileal bypass for morbid obesity. Effects on calcium and magnesium metabolism, vitamin D metabolites, and faecal lag time.

Calcium and magnesium balance, 47Ca turnover studies, and measurements of vitamin D metabolites were performed before and after 7-10 months of vitamin D2 treatment (36,000 IU/day) in eight patients bypass-operated 3-6 years earlier for gross obesity. All patients had received a daily supplementation of calcium (27 mmol/day) since operation. Before treatment the net calcium absorption and calcium balance were normal compared with that of nine normal controls. Vitamin D metabolites were within normal limits. The endogenous faecal calcium level was increased and the faecal lag time shortened. Bone biopsies revealed osteomalacia in three of the patients. Vitamin D2 treatment induced an increase in calcium absorption and renal excretion of calcium, a reduced bone resorption rate, a more positive calcium balance, and healing of osteomalacia. Moreover, the vitamin D2 treatment induced a prolongation and normalization of faecal lag time, an increase in magnesium absorption, and a more positive magnesium balance. The effect might be mediated through 25-hydroxyvitamin D (25-OHD), which increased, whereas serum levels of 1,25-dihydroxyvitamin D (1,25-(OH)2D) and 24,25-dihydroxyvitamin D (24,25-(OH)2D) were unchanged. The results indicate that in some bypass-operated patients high-dose vitamin D2 has a beneficial effect on calcium and magnesium metabolism.

Adult↗
PubMed1980

[The effect of the addition of vitamin E and selenium to sow feed ration on the concentration of vitamin E in the blood serum of piglets].

Under the experimental conditions of a clinic, the dynamics of vitamin E was studied in the blood serum of 57 piglets from birth to the age of 90 days. The piglets came from eight litters delivered by sows, four of which were given a ration with an addition of vitamin E (tocopherol acetate -- 100 i. u. per kg of feed) and selenium (0.1 ppm Se as Na2SeO3) during gravidity, and another four were given these supplements only during lactation. In the first group the piglets showed a high level of vitamin E immediately after birth, before the first sucking (4.048 mumol .1-1), which increased to the maximum average level at the age of 10 days (24.127 mumol .1-1). Then followed a marked decrease down to 1.679 mumol .1-1, recorded after weaning. In comparison with this, after the supplementation of the sow feed ration during lactation, the highest value of vitamin E concentration was found on the 5th day of age (21.482 mumol .1-1). The level of vitamin E gradually decreased, but still after weaning the average value was quite high (2.783 mumol .1-1). The results suggest the possibilities of eliminating the critical values of low vitamin E concentration in the blood serum of pigs at birth and after weaning.

Animal Feed↗