Pure Vitamin Research Articles

Diffusion of vitamin E in ultra-high molecular weight polyethylene

Vitamin E-doped, radiation crosslinked ultra-high molecular weight polyethylene (UHMWPE) is developed as an alternate oxidation and wear resistant bearing surface in joint arthroplasty. We analyzed the diffusion behavior of vitamin E through UHMWPE and predicted penetration depth following doping with vitamin E and subsequent homogenization in inert gas used to penetrate implant components with vitamin E. Crosslinked UHMWPE (65- and 100-kGy irradiation) had higher activation energy and lower diffusion coefficients than uncrosslinked UHMWPE, but there were only slight differences in vitamin E profiles and penetration depth between the two doses. By using homogenization in inert gas below the melting point of the polymer following doping in pure vitamin E, the surface concentration of vitamin E was decreased and vitamin E stabilization was achieved throughout a desired thickness. We developed an analytical model based on Fickian theory that closely predicted vitamin E concentration as a function of depth following doping and homogenization.

Human vitamin B 12 absorption measurement by accelerator mass spectrometry using specifically labeled 14 C-cobalamin

There is a need for an improved test of human ability to assimilate dietary vitamin B(12). Assaying and understanding absorption and uptake of B(12) is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry is uniquely suited for assessing absorption and kinetics of carbon-14 ((14)C)-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of (14)C in microliter volumes of biological samples with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B(12) in the range of normal dietary intake. The B(12) used was quantitatively labeled with (14)C at one particular atom of the dimethylbenzimidazole (DMB) moiety by exploiting idiosyncrasies of Salmonella metabolism. To grow aerobically on ethanolamine, Salmonella enterica must be provided with either preformed B(12) or two of its precursors, cobinamide and DMB. When provided with (14)C-DMB specifically labeled in the C2 position, cells produced (14)C-B(12) of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) (1 Ci = 37 GBq) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 microg, 2.2 kBq/59 nCi) of purified (14)C-B(12) was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B(12) assimilation.

A study on degradation kinetics of ascorbic acid in amla (Phyllanthus emblica L.) during cooking

The kinetics of ascorbic acid degradation in amla (Phyllanthus emblica L.) as well as in pure ascorbic acid solutions at initial concentrations present in amla over a temperature range of 50–120°C (steady-state temperature) has been studied. The ascorbic acid degradation followed first-order reaction kinetics where the rate constant increased with an increase in temperature. The temperature dependence of degradation was adequately modeled by the Arrhenius equation. The activation energies were found to be 4.09 kcal/mole for amla and 4.49 kcal/mole for pure vitamin solution. The degradation kinetics of ascorbic acid was also evaluated in normal open pan cooking, pressure-cooking and a newly developed and patented fuel-efficient EcoCooker (unsteady state heating process). A mathematical model was developed using the steady-state kinetic parameters obtained to predict the losses of ascorbic acid from the time–temperature data of the unsteady state heating processing method. The results obtained indicate the ascorbic acid degradation is of a similar order of magnitude in all the methods of cooking.

The Role of Vitamin D in the Prevention and Treatment of Osteoporosis

Vitamin D is essential for preventing and treating osteoporosis. Vitamin D enhances intestinal calcium absorption to help maintain blood calcium concentrations, necessary for bone mineralization and for muscle and nerve function. Vitamin D is metabolized to 25-hydroxyvitamin D (25OHD) in the liver and to the active form, 1,25-dihydroxyvitamin D [1,25(OH)2D] in the kidney. Inadequate vitamin D status contributes to increased bone turnover, secondary hyperparathyroidism, bone loss, fractures, muscle weakness, osteomalacia, and rickets in children. Vitamin D is synthesized in the skin upon exposure to sunlight. It is also found naturally in some foods and is present in fortified foods, in nonprescription supplements containing other vitamins or calcium, and as pure vitamin D in prescription and nonprescription forms. The concept of vitamin D adequacy has evolved well beyond the need for vitamin D for preventing rickets. Recommendations for vitamin D intake were increased in 1997 but continue to be debated. The best measure of vitamin D status is serum 25OHD, and recent studies suggest this should be at least 32 ng/mL. Many people fall short of this. Risks for poor vitamin D status include advanced age, minimal sun exposure, mal-absorption, and darkly pigmented skin. However, recent work suggests that many otherwise healthy individuals are inadequate in vitamin D. Although best known for its role in skeletal health, other roles for vitamin D in cancer, immunologic disease, and other aspects of health are being explored. Greater understanding of its role in skeletal health and overall well-being, and better avenues for assuring vitamin D adequacy for all people, are needed.

Colorimetric determination of ascorbic acid in pharmaceuticals using UVI_4-(2-pyridylazo)resorcinol complex

An analytical procedure based on the proportionate decrease in the color intensity of U V I -4-(2-pyridylazo)resorcinol complex with the increasing amount of vitamin C is described. The complex shows λ m a x at 530 nm. Beer's law holds well in the range 2-16 μg ml - 1 . The applicability of the method is tested by analyzing pure vitamin C solutions and multivitamin pharmaceuticals.

Hepatic Stellate Cell Proliferation is an Early Platelet-Derived Growth Factor-Mediated Cellular Event in Rat Cholestatic Liver Injury

After liver injury, hepatic stellate cells (HSC) undergo a pleiotropic response termed “activation” that also occurs in culture models and ultimately leads to the conversion of HSC into myofibroblasts expressing smooth muscle α-actin (α-SMA). The onset of HSC proliferation in primary culture coincides with the induction of platelet-derived growth factor receptor-β (PDGFR-β) expression, while platelet-derived growth factor (PDGF) is the most potent mitogen for culture-activated HSC. Yet, the mechanisms and the stage of activation required for HSC proliferation in the intact liver are still uncertain. In the present study, we analyzed the proliferative response of HSC to rat cholestatic liver injury and the role of PDGF in this response. After in vivo incorporation of bromodeoxyuridine (BrdU), pure vitamin A-containing HSC were isolated at different time points after bile duct ligation (BDL) or sham operation and were analyzed by means of flow cytometry. The induction of HSC proliferation, as ascertained by BrdU incorporation, occurred between 24 and 48 hours and reached a plateau as soon as 48 hours after BDL. Flow cytometry and immunoblot analyses of HSC indicated that the induction of proliferation in HSC coincided with the up-regulation of PDGFR-β protein on their surface but preceded that of α-SMA. A dose-dependent inhibition of PDGF-BB-induced HSC proliferation by STI571, a PDGF receptor tyrosine kinase inhibitor, was documented in vitro. Daily intraperitoneal injections of STI571 (20 mg/kg) caused a 60% reduction in BrdU positive isolated HSC and in the amount of desmin-immunoreactive sinusoidal cells on liver tissue sections in 48-hour bile duct-ligated rats. These results indicate that cholestatic liver injury elicits an early proliferative response in HSC that is mainly mediated by PDGF, and which precedes HSC phenotypic conversion into myofibroblasts.

Anaphylaxis to riboflavin (vitamin B2).

Vitamin supplements are used more commonly in normal healthy subjects than in patients with vitamin deficiency. Thiamine (vitamin B,) is the vitamin that most frequently induces allergic reactions. To the best of our knowledge, no case of anaphylaxis to riboflavin (vitamin B2) has thus far been reported in the literature. We describe a previously healthy 15-year-old boy in whom anaphylaxis developed several times after he drank one soft drink or took a single multivitamin tablet. This study was done to determine which of the many components found in the soft drink and vitamin tablet caused the anaphylactic reaction. In an outpatient clinic with the availability of complete resuscitative procedures, we performed single-blind prick skin tests and intradermal skin tests on the patient with various pure vitamin components of the soft drink and the multivitamin tablet. Physiologic saline and histamine were used for negative and positive controls, respectively. Riboflavin, a component of both the soft drink and the vitamin tablet, produced positive reactions on intradermal skin tests in the patient. Positive reactions were not present in the normal control subjects. Riboflavin is a previously unreported cause of anaphylaxis. Free-form riboflavin may potentially be associated with an anaphylactic reaction. It is a vitamin widely used in many patients with chronic disease and in healthy subjects. Vitamin B2 must be considered as a cause of anaphylaxis.

Nature: "Green" Chemistry, Natural Antioxidants, and a DNA-Fueled Machine

This report from Nature summarizes two breakthroughs in green chemistry: A rechargeable Mg battery that might one day become an environmentally benign replacement for our current car batteries, and new polymers that greatly improve the solvent properties of supercritical CO2. Another article highlighted in this column confirms that fresh apples contain oxygen radical scavengers that are more potent than pure vitamin C. Finally, DNA-fueled molecular tweezers are featured that take advantage of the specific interactions between complementary strands of DNA to bring about opening and closing of this nano-device.

Comparison of methods for determination of vitamin B12 in microbial material

Three different methods for the measurement of vitamin B12 were compared: two spectrophotometric methods and an HPLC one. When the pure vitamin was used, the results obtained using all three methods were similar, but when samples from microbial material were used, the results were different. The HPLC method could distinguish the true vitamin B12 from the different vitamin B12 analogues whereas the spectrophotometric methods could not.

Relative bioavailability of riboflavin in cows' milk and fermented milk using rat bioassay

Abstract Bioavailability of riboflavin from cows' milk and fermented milk was assessed using riboflavin-depleted rats. The fermented milk was prepared using Lactococcus lactis subsp. lactis, and cremoris and Propionibacterium shermanii as starter cultures. Rats were depleted of riboflavin by feeding a riboflavin-free diet for 30 days. At this stage, hepatic riboflavin and erythrocyte glutathione reductase (EGR) activity decreased significantly (P Relative bioavailability (RBV), relative to pure vitamin, of riboflavin from milk and fermented milk was determined by slope ratio statistics using multiple linear regression with hepatic riboflavin, EGR activity and AC on FAD addition as response criteria. RBV for milk and fermented milk were 144 and 161% with hepatic riboflavin as a response criterion, 135 and 154% with EGR activity as a criterion and 116 and 125% with AC as a criterion. RBVs were significantly greater for milk and fermented milk than for the pure vitamin.

25-Hydroxylation of vitamin D3 in the human hepatoma cell lines Hep G2 and Hep 3B.

Two human hepatoma cell lines, Hep G2 and Hep 3B, were screened for vitamin D3-25-hydroxylase enzyme activity by incubation with radioactive vitamin D3. A compound co-chromatographing with 25-OH-D3 was synthesized in both cell lines but its rate of synthesis was tenfold greater in Hep 3B than in Hep G2 cells. The identity of the compound was confirmed by comparing its chromatographic properties with authentic 25-OH-D3 on three different high pressure liquid chromatography systems. Its production was suppressed by adding fetal calf serum (10%), lipoprotein-deficient fetal calf serum, or pure vitamin D-binding globulin to the medium. The mechanism of action of these plasma proteins appears to involve retardation of uptake of the substrate. These two cell lines offer considerable potential as defined in vitro models for studying the effects of physiological factors on the 25-hydroxylation of vitamin D3.

Purification of vitamin D binding protein from human plasma using high performance liquid chromatography

Vitamin D binding protein/group-specific component was purified from human plasma by chromatographic techniques utilising high performance liquid chromatography and by traditional low pressure Chromatographic techniques alone. Use of high performance liquid chromatography considerably reduced the time taken to prepare pure vitamin D binding protein and increased the yield to 16% compared with 2.8% using the traditional methods. The vitamin D binding protein prepared by high performance liquid chromatography was shown to be highly pure by amino acid sequence, SDS gel electrophoresis and by antibody production. The amino acid sequence was confirmed and extended. The affinity constants of the high pressure liquid chromatography purified vitamin D binding protein for 25 hydroxycholecalciferol (25 OHD 3) and 1,25 dihydroxycholecalciferol 1,25(OH) 2D 3 were 1.9 × 10 7 mol/l and 2.6 × 10 6 mol/l, respectively.

Phyllohydroquinone (Vitamin K1H2) and Phylloquinone (Vitamin K1): Purification and Spectral Analysis

Abstract Simple procedures for the preparation of pure phyllohydroquinone and phylloquinone are described. Phylloquinone is reduced by sodium dithionite and the reduced vitamin is purified by reverse phase high performance liquid chromatography. The essential spectral properties of the pure vitamins in ethanol and methanol are cited. The data provide a convenient spectral method for the accurate determination of the absolute concentrations of the oxidized and reduced vitamins and the rates of oxidation of the reduced vitamin. Pure, dry phyllohydroquinone may be safely stored at -70[ddot]C under nitrogen for a period of months. The stability of Phyllohydroquinone in methanol at 25.0 ± 0.1[ddot]C is also reported.

Vitamin A, beta carotene, and hereditary buphthalmus in the rabbit.

Rabbits with hereditary buphthalmus, AXBU/J strain, were fed various levels of supplementary vitamin A or its precursor beta carotene, in addition to a vitamin A deficient diet, to test the hypothesis that the bu gene acts by reducing either the conversion of beta carotene to vitamin A or the utilization of vitamin A. Measurements were taken on an age series of skulls of manifest and of prodromal buphthalmics to see if there were any observable differences in optic foramen size associated with the clinical manifestations of buphthalmus. Constriction of the optic nerve by bone alteration has been reported to be associated with vitamin A deficiency. The original hypothesis was not a tenable one as the rabbit with hereditary buphthalmus readily converted beta carotene to vitamin A, no bony changes in the optic foramen were observed with manifest buphthalmus, high levels of beta carotene or vitamin A were unable to block the clinical development of buphthalmia, and no correlation was observed between intraocular pressure and serum vitamin A levels in rabbits fed either beta carotene or pure vitamin A.

Availability of vitamin B6 and pantothenate in an average American diet in man

The availability of vitamin B6 and pantothenate in an average American diet was assessed healthy male volunteers. The subjects received two types of diets, both nutritionally equivalent to the average American diet: period 1 (35 days), semipurified formula diet (low in both vitamins) with daily supplements of 1.1 mg pyridoxine and 8.2 mg pantothenate; period 2 (35 days), natural food sources, providing 2.3 mg vitamin B6 and 11.5 mg pantothenate/day; period 3 (21 days), formula diet, providing 2.7 mg pyridoxine and 8.2 mg pantothenate/day. Daily protein intake was 96 g throughout the study. Vitamins in food and urine samples were determined microbiologically and plasma pyridoxal phosphate by a tyrosine apodecarboxylase radioassay method. Compared to the availability of the pure vitamins as 100%, the availability of vitamin B6 ranged from 61 to 81% with a mean of 71% using plasma pyridoxal phosphate data, and ranged from 73 to 92% with a mean of 79% according to urinary vitamin B6 data. Availability of pantothenate ranged from 40 to 61% with a mean of 50%, according to urinary pantothenate data. The average American diet used in our study contained 1.7 and 5.8 mg/day of available vitamin B6 and pantothenate, respectively.

Determination of Vitamin Bi in Pharmaceutical Preparations Using a Lead Ion Selective Electrode and Atomic Absorption Spectroscopy

Simple, rapid, and accurate methods have been developed for determining vitamin B1 in pharmaceutical preparations without prior separation of the vitamin. The methods are based on the desulfurization reaction with potassium plumbite and measurement of the unreacted lead(II) ions at 217 nm using atomic absorption spectroscopy (AAS), or by titration with EDTA at pH 4.5 with the lead ion selective electrode and Gran's plot. The results compare favorably with those obtained using the USP fluorometric method. Recoveries of pure vitamin B1 averaged 99.1%, with a standard deviation of 0.8%, and 99.0%, with a standard deviation of 0.7%, for the AAS and ion selective electrode procedures, respectively.

Vitamin C increase in aerated potato slices

Increasing the vitamin C content in potato slices by aeration prior to the pre-cooking water blanching step in the production of dehydrated potato granules was investigated as a possible means of offsetting the high losses experienced in the process. Slices of 6 mm thickness of Netted Gem variety that were aerated overnight at 22°C in a dark and moist atmosphere increased their apparent vitamin C content by 38.5%, while longer aeration for up to 52 h brought about a linear increase of close to 4% per hour. Beyond 52 h the rate of vitamin gain was slower, and was accompanied by objectionable browning. The gains were dependent on the length of time the tubers were stored before use, the presence of oxygen, and the thickness of the slices. Overnight aeration at 4°C resulted in a gain that was one fifth that found for the corresponding time at 22°C, while a longer period decreased this factor to one ninth. Slices aerated under water did not show a change in vitamin content. The vitamin C increase in aerated slices is due to actualde novo biosynthesis of L-ascorbic acid and not to reductones, amino acid — sugar interaction products, or to the presence of dehydroascorbic acid. This was proven by titration with 2,6-dichlorophenolindophenol, and by the 2,4-dinitrophenylhydrazine method in which a thin layer chromatographic purification of the vitamin C osazone was carried out. Additional confirmation came from polarographic recordings of the ascorbic acid anodic wave, and of the cathodic wave of the vitamin C — o-phenylenediamine condensation products, with or without chloroform extraction. Electron spin resonance spectra of the juices from the slices also confirmed the findings. Pure 1 or 100 mM aqueous L-ascorbic acid, when oxygenated at pH 5.6, the pH of the potato, or at pH 8.2, gave a hyperfine structure with a splitting constant for the doublet of 1.8 Gauss. However, potato juice did not give a spectrum that could be resolved to that degree. The spectra characteristic of radicals from triose reductone or reductic acid were absent. Potato peel and scalp had a high apparent vitamin C content, and gave strong radical signals that had lifetimes of 48 h or longer, but their behavior and position did not coincide with the signal for pure vitamin C. The finding that true vitamin C is in fact synthesized by aeration of slices may not only be beneficial in the household, but also may have potential practical application in the processing of potatoes in which destruction of vitamin C can occur to an unacceptable extent.

The influence of soil water extract and thiamine on the growth of Cladophora glomerata

Soil water extract (SWE) has been used for decades to supplement certain algal and fungal cultures, but its active components remain essentially unknown. Cladophora glomerata, an attached green alga which has become a problem in several of the Laurentian Great Lakes and elsewhere, is one species that grows well on synthetic media supplemented with SWE. Unialgal cultures were used to investigate the nature of the active components in SWE with the hope that insight of the nutritional requirements of this alga would be gained.Analysis of SWE showed that an organic heat-labile component was significant, and when thiamine was substituted for SWE, it was found to provide 80% of the stimulation induced by SWE. The presence of thiamine in two samples of SWE was verified, and concentrations of 3 and 10 μg/litre were determined using the Phycomyces bioassay. Subsequent investigations of the requirement of thiamine by C. glomerata demonstrated that 1 μg/litre, provided either by SWE or as the pure vitamin, stimulated satisfactory growth, while 10 μg/litre is the apparent optimum concentration.

Microbiological assay of vitamin B6 by thin-layer cup-plate method with Saccharomyces carlsbergensis.

The agar-plate diffusion method for determination of vitamin B6 in natural products was presented, which improved on its weak point of relative insensitivity by using a thin-layer plate technique.The optimum conditions for the assay were proposed as follows. Assay medium: Atkin's basal medium with minor modifications and 1% agar, 0.75mm plate thickness (thin-layer), pH 5.0 to 6.0. Standard solutions of vitamin B6: pH 5.0 to 6.0. Inoculum size of test organism: 0.075 optical density in final. Incubation: 30°, 12 to 16 hr.Under our conditions a reproducible, clear and sharply-defined growth zone on the assay plate was steadily obtained and there was a linearity of the dose-response to pure vitamin B6 solution over a wide range of 20 to 2, 000mμg/ml. In the statistical analysis of the results the probable errors amounted to only 4 to 5%. The total vitamin B6 values in some natural materials obtained by this method were as equal as those determined with turbidimetric ones. Also, recovery experiments were successful enough and the dose-response line for all samples used hardly had any drift from that for pure vitamin B6 solution.This method is simple, accurate and adequate for the routine assay of a large number of samples.

Nutritional studies on Pycnidiophora dispersa Clum, with particular reference to perithecia formation.

Pycnidiophora dispersa Clum was isolated from jute and found to be a strong decomposer of this fiber, but not of pure cellulose. The effect of certain carbohydrates, nitrogen compounds, trace elements, and accessory growth factors as well as pH and temperature on the growth and perithecia formation of this fungus was studied. None of the carbohydrates tested gave appreciable growth or perithecia formation in liquid medium, but an initial low concentration of each produced both when tested on solid medium. Of the nitrogen compounds tested only peptone had any effect, which was probably caused by impurities. Pure vitamins and trace elements induced neither growth nor fruiting. Malt extract, yeast extract, and the culture filtrate of an Actinomyces sp. all stimulated growth and fruiting. The filtrate factor and malt extract factor were found to be insoluble in organic solvents, heat-resistant, and adsorbed by charcoal.