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At least 1,423 records · Page 79Linked to original sources
PubMed1978

[Vitamin E levels in the ovine serum after administration of vitamin E and selenium].

The effects of drugs containing vitamin E for peroral administration (Combinal E), intramuscular injection (Erevit) and parenteral administration of a combined drug containing vitamin E and selenium (Selevit) on vitamin E levels in the ovine blood serum were studied. A uniform dose of 15 mg tocopherol acetate per 1 kg live weight was administered to the experimental animals. The level of vitamin E after the peroral administration of Combinal E was affected to a lesser extent than in swine and calves. The serum was examined before and after saponification to determine the effect of the intramuscular injection of Erevit; it was found out that tocopherol acetate prevailed in the blood serum in the first hours after such a route of administration. The best results were obtained after both subcutaneous and intramuscular administration of Selevit, the levels of free tocopherol showing high values even at the end of the experiments. These results may be made use of in determining effective preventive and therapeutic measures to do away with the white muscle disease in practice.

Administration, Oral↗
PubMed1978

Quantitation of radio-labelled vitamin K1 and vitamin K1 epoxide in plasma by high pressure liquid chromatography.

A convenient, accurate and reproducible high pressure liquid chromatographic method for the quantitation of radio-labelled vitamin K1 and vitamin K1 epoxide in plasma is described. The method involves the determination of total ether extractable radioactivity, and a chromatographic separation to determin the relative quantities of radio-labelled vitamin K1 and vitamin K1 epoxide. The method is useful over a wide range of ratios of the two compounds, and has a coeffcient of variation of approximately 5%.

Chromatography, High Pressure Liquid↗
PubMed1980

Renal parathyroid hormone-dependent adenylate cyclase in vitamin D-deficient rats. Inhibition by hydroxylated vitamin D3 metabolites.

The adenylate cyclase activation by bovine synthetic parathyroid hormone (bPTH) (1-34) was studied in vitro in kidney plasma membranes from D-deficient (D-Mb) or normal (D+Mb) rats. In D-Mb, the apparent affinity of parathyroid hormone (PTH) for membranes (170 +/- 30 nM) was significantly higher than that measured in D+Mb (55 +/- 5 nM). The maximum velocity of the PTH-stimulated adenylate cyclase was significantly higher in D+Mb than in D-Mb (163.0 +/- 13.7 and 93.4 +/- 6.7 pmol of cAMP/mg of protein/min, respectively). The action of vitamin D metabolites on the adenylate cyclase stimulation by PTH was then studied in vitro in D-Mb and D+Mb. In D-Mb, 25-hydroxyvitamin D3, 24,25-, and 1, 25-dihydroxyvitamin D3 significantly inhibited cAMP production in the presence of 0.87 microM of bPTH. Vitamin D3 had no effect. Maximal inhibition (86%) was observed for 1,25-dihydroxyvitamin D3. 1,25-Dihydroxyvitamin D3 decreased the maximum velocity of PTH-stimulated adenylate cyclase but did not modify the bPTH apparent affinity for D-Mb. The vitamin D3 metabolites tested did not modify the cyclase stimulation by isoproterenol, sodium fluoride, or 5'-guanylylimidodiphosphate. The presence of 1,25-dihydroxyvitamin D3 or 25-hydroxyvitamin D3 did not increase the (Na-K)-ATPase or the phosphodiesterase activities. In the presence of 1,25-dihydroxyvitamin D3 and bPTH, the apparent affinity of ATP for the catalytic moiety was not modified. The maximum velocity was decreased. These results suggest an in vitro interaction between hydroxylated vitamin D metabolites and kidney membranes PTH receptor.

24,25-Dihydroxyvitamin D 3↗
PubMed1978

Analysis of fat-soluble vitamins. XIX. Collaborative studies on the chemical assay for vitamin D concentrates.

In 1971, a chemical method for the assay of vitamin D in concentrates containing only vitamin D was collaboratively studied by 14 laboratories, using 6 different samples from 2 European manufacturers. On the basis of these results, the laboratories were divided into 2 groups: 5 with significant laboratory biases of greater than or equal to 2%, and 9 laboratories with nonsignificant bias. The 9 laboratories were subdivided into 2 groups which differed significantly as to reproducibility within laboratories. The reproducibility between laboratories, expressed as a standard deviation in per cent with 95% confidence limits, was 1.2% (confidence range 0.6-7.3) and 4.7% (confidence range 2.4-29.3) for 3 and 6 laboratories, respectively. A second collaborative test was performed in 1974, using 12 vitamin D resin samples in oil from 3 United States manufacturers, to compare 2 chemical vitamin D assay methods (with and without maleic anhydride) and to compare results from the chemical and biological methods; 9 laboratories participated in the chemical method study and 3 in the rat bioassay study. The correlation of results of the chemical method including maleic anhydride treatment and the rat bioassays was satisfactory. The reproducibility of the chemical method was about the same as that in the first collaborative test.

Fats↗
PubMed1978

Relationship between vitamin K-dependent carboxylation and vitamin K epoxidation.

It has been postulated that the liver microsomal conversion of vitamin K hydroquinone to its 2,3-epoxide (epoxidase activity) is coupled in some obligatory fashion to the vitamin K-dependent carboxylation (carboxylase activity) event also occurring in microsomes. This hypothesis is supported by the observations that the requirements for the two reactions are similar and that conditions that promote increased carboxylation increase the epoxidase activity. It has now been shown that both of these reactions are localized in the rough microsomal fraction of a cellular homogenate, and that both activities appear to be located on the luminal rather than the outer surface of microsomal membrane vesicles. The epoxidase activity has been found to be enriched as the microsomal carboxylase activity is fractionated, and a microsomal inhibitor of the carboxylase activity had been shown to also inhibit the epoxidase activity. The enzyme glutathione peroxidase inhibits both of these activities, suggesting that a hydroperoxide of the vitamin might be an intermediate for both reactions. The organic hydroperoxide t-butyl-OOH has also been shown to have weak vitamin K-like activity in an in vitro system. These data strengthen the hypothesis that these two reactions are related, perhaps through a common intermediate, but do not provide a definite molecular role for this interrelationship.

1-Carboxyglutamic Acid↗
PubMed1978

Vitamin B12 and vitamin B12 binding proteins in iron deficiency anaemia.

Vitamin B12 and vitamin B12 binding proteins were determined in 20 patients with iron deficiency anaemia who showed low haemoglobin, haematocrit, serum iron levels and hypochromic microcytic red blood cells. The serum vitamin B12 levels in these patients were significantly lower than that of the normal subjects. Nine of 20 patients had serum vitamin B12 less than 350 pg/ml. There was a significant increase in serum UBBC and TBBC levels in patient group and 9 of 20 patients had higher UBBC values than those of the normal subjects. The absolute values of TCI and TCII increased significantly while TCIII was within the normal limit even though the percentage of UBBC were not different from that of the normal subjects.

Anemia, Hypochromic↗
PubMed1994

Vitamins as radioprotectors in vivo. II. Protection by vitamin A and soybean oil against radiation damage caused by internal radionuclides.

Tissue-incorporated radionuclides impart radiation energy over extended periods of time depending on their effective half-lives. The capacity of vitamin A dissolved in soybean oil to protect against the biological effects caused by internal radionuclides is investigated. The radiochemicals examined are DNA-binding 125IdU, cytoplasmically localized H125IPDM and the alpha-particle emitter 210Po citrate. As in our previous studies, spermatogenesis in mice is used as the experimental model and spermatogonial cell survival is the biological end point. Surprisingly, soybean oil itself provides substantial and equal protection against the Auger effect of 125IdU, which is comparable to a high-LET radiation effect, as well as the low-LET effects of H125IPDM, the dose modification factors (DMFs) being 3.6 +/- 0.9 (SEM) and 3.4 +/- 0.9, respectively. The protection afforded by the oil against the effects of 5.3 MeV alpha particles emitted by 210Po is also significant (DMF = 2.2 +/- 0.4). The presence of vitamin A in the oil further enhanced the radioprotection against the effect of 125IdU (DMF = 4.8 +/- 1.3) and H125IPDM (DMF = 5.1 +/- 0.6); however, no enhancement is provided against the effects of alpha particles. These interesting results with soybean oil and vitamin A, together with data on the subcellular distribution of the protectors, provide clues regarding the mechanistic aspects of the protection. In addition, the data for vitamin A reaffirm our earlier conclusion that the mechanism by which DNA-bound Auger emitters impart biological damage is primarily indirect in nature.

Animals↗
PubMed1977

Studies on vitamin E and selenium deficiency in young pigs. II. The hydrogen peroxide hemolysis test and the measure of red cell lipid peroxides as indices of vitamin E and selenium status.

The usefulness of the hydrogen peroxide hemolysis test and the measure of red cell lipid peroxides as indices of vitamin E and selenium deficiency in swine has been evaluated. Results indicated that although the hydrogen peroxide hemolysis test may be of some indication of the vitamin E status, it is not a reliable index of vitamin E deficiency in swine, at least on an individual basis. In contrast, the measure of red cell lipid peroxides can be considered a reliable test for vitamin E deficiency in swine. The hydrogen peroxide hemolysis test and the red cell lipid peroxides were not significantly affected by selenium deficiency.

Animals↗
PubMed1993

[Vitamin D dependency and vitamin D resistance].

Vitamin D dependency is classified into two clinical disorders which are caused by genetic defect of vitamin D metabolism. Vitamin D dependent rickets type I and type II are the deficiency of 25-hydroxyvitamin D-1 alpha-hydroxylase and the defect of receptor for 1 alpha,25-dihydroxyvitamin D, respectively. In contrast, vitamin D resistance shows hypophosphatemia derived from disorder(s) of phosphate transport system in renal brush border membrane. There are three clinical entities such as hereditary hypophosphatemic rickets with hypercalciuria, familial hypophosphatemic rickets and oncogenic hypophosphatemic osteomalacia. However, the real pathogenesis of these disorders have not well been understood at present.

Humans↗
PubMedDate not supplied

Effects of sodium ascorbate (vitamin C) and 2-methyl-1,4-naphthoquinone (vitamin K3) treatment on human tumor cell growth in vitro. II. Synergism with combined chemotherapy action.

The growth inhibitory effects of a combined application of sodium ascorbate (Vitamin C) and 2-methyl-1,4-naphthoquinone (Vitamin K3) together with various chemotherapeutic agents has been examined on in vitro cultured human endometrial adenocarcinoma (AN3CA) cells. Combined vitamin treatment and chemotherapy in well defined conditions of cell confluence and at the dose levels applied result in a synergistic effect on growth inhibition. The combined vitamins when reaching their own synergistic cytotoxicity levels frequently obscure the additional synergistic effects attributable to the chemotherapeutic agents. Apart from the specific cytotoxic characteristics of the chemotherapeutic drugs examined, the formation of reactive oxygen radicals during treatment, possibly accentuated by less defined secondary mechanisms, appears essentially responsible for the observed stimulated cytotoxicity.

Adenocarcinoma↗
PubMed1996

[Effect of vitamin D receptor gene polymorphism on vitamin D therapy for postmenopausal bone loss].

In order to assess the effect of vitamin D receptor (VDR) gene polymorphisms on vitamin D3 therapy for postmenopausal bone loss. Thirty-four Japanese postmenopausal women, administered vitamin D3 (Alfarol 1.0 microgram/day) and Ca (2.0 g/day) for 18 months, were analyzed by RFLP. Bone mineral density (BMD) at the lumbar spine (L2-4) and Os-calcis were measured every 6 months by dual energy X-ray absorptiometry (DXA) and single energy X-ray absorptiometry (SXA). VDR gene allelic polymorphisms were assessed by Bsm 1 endonuclease restriction after specific PCR amplification. Genotypic polymorphism was defined as BB, bb and Bb. The genotypes were BB in 1 (3.1%), Bb in 13 (40.6%), and bb in 18 (56.3%). The women in these two major VDR genotype groups (Bb and bb) were similar in their backgrounds (in terms of age, body mass index, and BMD in premedication), but the VDR genotype was associated with the percent of change in BMD after treatment. In Group-Bb, the mean percent increases in L2-4 BMD were 3.2%, 4.9% and 4.1% at 6, 12 and 18 months. In contrast, in Group-bb they were 0.8%, 1.8% and 1.2% at the same points. Analysis of VDR alleles may prove useful in selecting the vitamin D therapy for osteopenia before treatment.

Aged↗
PubMed1977

Analysis of fat-soluble vitamins. XV. Confirmation of isotachysterol in vitamin D concentrates.

The reaction with maleic anhydride yielding Diels-Alder adducts is used to distinguish vitamin D isomers. Treatment at 100 degrees C for 3 hr eliminates the fast-reacting (tachysterol and trans-vitamin D) and slow-reacting (cis-vitamin D and previtamin D) isomers. However, isotachysterol is not eliminated. The procedure has been incorporated as a confirmation test for isotachysterol in the official final action method for the determination of vitamin D in concentrates, 43.B14-43.B24.

Ergosterol↗
PubMed1998

Background and rationale behind the SU.VI.MAX Study, a prevention trial using nutritional doses of a combination of antioxidant vitamins and minerals to reduce cardiovascular diseases and cancers. SUpplementation en VItamines et Minéraux AntioXydants Study.

The "SUpplementation en VItamines et MinérauxAntioXydants" (SU.VI.MAX) study is a randomized double-blind, placebo-controlled, primary prevention trial designed to test the efficacy of daily supplementation with antioxidant vitamins (vitamin C, 120 mg; vitamin E, 30 mg; and beta-carotene, 6 mg) and minerals (selenium, 100 micrograms; and zinc, 20 mg), at nutritional doses (one to three times the daily recommended dietary allowances), in reducing the frequency of major health problems in industrialized countries, and especially the main causes of premature death (cancers and cardiovascular diseases). The study involves 12,735 eligible subjects (women aged 35 to 60 years; men aged 45 to 60 years) included in 1994 in France. They will be followed up for 8 years. The objectives and the specific design of this intervention study are linked to its public health aim. The targeted population is the general population (not simply high-risk subjects) and the antioxidant agents tested are being administered at a level which is not pharmacologic and which may be attained by dietary intake of natural sources of these micronutrients and/or enriched foods. The amounts we are testing in the SU.VI.MAX study are those which, in observational studies have been associated with the lowest risk of diseases. This report presents the rationale and discusses the justification of the design, doses and combination of antioxidant micronutrients chosen in the SU.VI.MAX study.

Adult↗
PubMed1998

Elevated PTH levels in hypovitaminosis D are more rapidly suppressed by the administration of 1,25-dihydroxy-vitamin D3 than by vitamin D3.

OBJECTIVE: To assess markers of bone metabolism in two groups of inpatients with hypovitaminosis D and elevated PTH levels receiving two different vitamin D medications. METHODS: 26 patients with secondary hyperparathyroidism (2 degrees HP) were treated either with 800 IU cholecalciferol and 1000 mg calcium or 0.5 microgram calcitriol plus 500 mg calcium daily for 6 months. 25-OH-vitamin D3, 1,25-dihydroxy-vitamin D3, intact PTH, calcium and urinary N-telopeptides of bone collagen I were measured at baseline, 3 and 6 months. RESULTS: PTH levels decreased earlier in the calcitriol group than in the cholecalciferol group. After six month no difference could be documented. Lowering of urinary N-telopeptides excretion was observed in both groups. CONCLUSION: The use of both forms of vitamin D supplementation appears to be useful for patients with hypovitaminosis D, elevated PTH levels and high telopeptide excretion.

Administration, Oral↗
PubMed1993

Vitamin D receptors in a naturally vitamin D-deficient subterranean mammal, the naked mole rat (Heterocephalus glaber): biochemical characterization.

1,25-dihydroxyvitamin D3 (1,25(OH)2D3), the hormonally active metabolite of vitamin D3 interacts with its nuclear/cytosolic receptor to induce biological responses in target tissues. Naked mole rats appear to be naturally deficient in vitamin D. The questions arise whether these animals possess the 1,25(OH)2D3 receptor (VDR) and whether they are capable of responding to 1,25(OH)2D3 via receptor-mediated pathways. Various tissues (intestine, kidney, Harderian glands, and skin) were examined for the presence and biochemical characterization (as indicated by saturation, sucrose density gradient, DNA binding, and ligand-competitive analysis) of VDRs. In addition homologous upregulation of VDRs in these tissues and induction of 25-hydroxyvitamin D3-24-hydroxylase (24-OHase) in the kidney was studied as indicators of the VDR-mediated biological responses. Naked mole rats have VDRs in the intestine, kidney, and Harderian gland but not in skin. Biochemical characterization of VDRs and VDR-mediated biological responses in the intestine and kidney correspond to those found in similar target tissues of other mammals. Harderian gland VDR is at a lower concentration yet shows a markedly higher affinity and selectivity to 1,25(OH)2D3 than that of the intestine and kidney. Vitamin D3 supplementation resulted in VDR upregulation in the intestine and kidney and induced renal 24-OHase but had no effects on VDRs in Harderian glands. These data demonstrate that naked mole rats possess VDRs in intestine, kidney, and Harderian glands; these VDRs differ in their biochemical characteristics.

Animals↗
PubMed1993

Intercomparison of methods for the determination of vitamins in foods. Part 1. Fat-soluble vitamins.

An intercomparison of methods involving 18 European laboratories was organized to assess the state-of-the-art of vitamin determination in foods. Each laboratory received identical samples of dry food reference material (homogeneous powders, milk powder, pork muscle and haricot vert beans), which were recently certified for major dietary components and elements. Each laboratory was requested to perform the analyses by its own methods. Results for fat-soluble vitamins are reported. All participants isolated the fat-soluble vitamins by alkaline saponification. For retinol, only high-performance liquid chromatography (HPLC), reversed- or normal-phase, was applied, with both ultraviolet (UV) and fluorescence detection. Results in milk powder showed a relative standard deviation of reproducibility (RSDReprod) of only 10%. Carotene was determined by HPLC (reversed- and normal-phase) and with open-column chromatography at atmospheric pressure. For beta-carotene results in milk powder agreed very well; the RSDReprod was 14%. The values reported for haricot vert beans showed poor agreement; the RSDReprod was 52%. A major part of this variability was due to differences in methodological principles. The results for alpha-tocopherol in milk powder and haricot vert beans agreed very well, with RSDSReprod of 16 and 15%, respectively. Only HPLC (reversed- and normal-phase) with UV and fluorescence detection was applied.

Animals↗
PubMedDate not supplied

Influence of cigarette smoking on vitamin E, vitamin A, beta-carotene and lycopene concentrations in human pre-ovulatory follicular fluid.

Increasing evidence suggests that fat soluble vitamins and micronutrients have the potential for local modulation of follicular development. Cigarette smoking has been associated with accelerated follicular depletion and derangement of reproductive functions. The present study was initiated to investigate the impact of cigarette smoking on follicular and plasma concentrations of vitamin A, vitamin E, lycopene and beta-carotene. Samples were collected from 17 smokers and 43 non-smoking women undergoing assisted reproduction techniques. Assays were carried out by a reverse-phase high-pressure liquid chromatography (HPLC) method. Smokers had significantly (P < 0.05) lower levels of follicular fluid beta-carotene in comparison to non-smokers (0.02 +/- 0.02 vs. 0.09 +/- 0.02, respectively). No other significant influences on follicular and plasma concentrations were noted. Smokers showed a significantly (P < 0.05) lower fertilization rate in comparison to non-smokers, (55.9 % vs. 71.5 % , respectively). It is postulated that follicular depletion of the antioxidant beta-carotene occurs in response to oxidative stress imposed by cigarette smoke.

Adult↗