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Showing papers on "B vitamins published in 1994"


Journal ArticleDOI
TL;DR: The data suggest the existence of an autoregulatory loop whereby I kappa B alpha regulates the activity of transcription factor NF-kappa B, which in turn regulates the I k Kappa B alpha activity.
Abstract: Transcription factor NF-kappa B regulates the expression of a plethora of genes. The activity of NF-kappa B proteins is regulated by I kappa B proteins. We report that induction of I kappa B alpha, a member of the I kappa B family of proteins, is preceded by activation of NF-kappa B complex. The promoter of the I kappa B alpha gene contains a kappa B site that is directly involved in its induction by the NF-kappa B complex. Degradation of I kappa B alpha protein precedes activation of NF-kappa B DNA binding activity, whereas newly synthesized I kappa B alpha protein inhibits NF-kappa B activity. If the degradation of I kappa B alpha is prevented, the induction of DNA binding activity of NF-kappa B complex is severely curtailed. These data suggest the existence of an autoregulatory loop whereby I kappa B alpha regulates the activity of transcription factor NF-kappa B, which in turn regulates the I kappa B alpha activity.

410 citations


Journal ArticleDOI
TL;DR: Results demonstrate that tolerance to LPS is determined by post-receptor mechanisms that involve an altered composition of the NF-kappa B complex.

296 citations


Journal ArticleDOI
TL;DR: Results suggest that the modified RsbV, present in crude cell extracts, is phosphorylated, and support a model whereby £bV binds directly to £bW and blocks its ability to form the RsbW-sigma B complex.
Abstract: The activity of sigma B, a secondary sigma factor of Bacillus subtilis, is primarily controlled by an anti-sigma factor protein (RsbW) that binds to sigma B and blocks its ability to form an RNA polymerase holoenzyme (E-sigma B). Inhibition of sigma B by RsbW is counteracted by RsbV, a protein that is essential for the activation of sigma B-dependent transcription. When crude B. subtilis extracts were fractionated by gel filtration chromatography or electrophoresis through nondenaturing polyacrylamide gels, a complex composed of RsbW and RsbV that is distinct from the previously observed RsbW-sigma B complex was detected. In analogous experiments, RsbX, an additional regulator of sigma B-dependent transcription that is thought to act independently of RsbV-RsbW, was not found to associate with any of the other sigB operon products. Two forms of RsbV were visualized when crude cell extracts of B. subtilis were subjected to isoelectric focusing (IEF), with the more negatively charged RsbV species absent from extracts prepared from RsbW- strains. In vitro, RsbV became phosphorylated when incubated with ATP and RsbW but not with ATP alone. The phosphorylated RsbV species comigrated during IEF with the RsbW-dependent form of RsbV found in crude cell extracts. These results suggest that the modified RsbV, present in crude cell extracts, is phosphorylated. When gel filtration fractions containing RsbV-RsbW complexes or RsbV alone were subjected to IEF, only the unmodified form of RsbV was found associated with RsbW. The presumed phosphorylated variant of RsbV was present only in fractions that did not contain RsbW. The data support a model whereby RsbV binds directly to RsbW and blocks its ability to form the RsbW-sigma B complex. This activity of RsbV appears to be inhibited by RsbW-dependent phosphorylation.

209 citations


Journal ArticleDOI
TL;DR: It is demonstrated that Tax-stimulated nuclear expression of NF-kappa B in both HTLV-I-infected and Tax-transfected human T cells is associated with the phosphorylation and rapid proteolytic degradation of I kappa B alpha, and induction of nuclear c-Rel expression is activated by the RelA (p65) subunit of NF, which activates transcription of the c-rel gene through an intrinsic kappaB enhancer element.
Abstract: The tax gene product of human T-cell leukemia virus type I (HTLV-I) is a potent transcriptional activator that both stimulates viral gene expression and activates an array of cellular genes involved in T-cell growth. Tax acts indirectly by inducing or modifying the action of various host transcription factors, including members of the NF-kappa B/Rel family of enhancer-binding proteins. In resting T cells, many of these NF-kappa B/Rel factors are sequestered in the cytoplasm by various ankyrin-rich inhibitory proteins, including I kappa B alpha. HTLV-I Tax expression leads to the constitutive nuclear expression of biologically active NF-kappa B and c-Rel complexes; however, the biochemical mechanism(s) underlying this response remains poorly understood. In this study, we demonstrate that Tax-stimulated nuclear expression of NF-kappa B in both HTLV-I-infected and Tax-transfected human T cells is associated with the phosphorylation and rapid proteolytic degradation of I kappa B alpha. In contrast to prior in vitro studies, at least a fraction of the phosphorylated form of I kappa B alpha remains physically associated with the NF-kappa B complex in vivo but is subject to rapid degradation, thereby promoting the nuclear translocation of the active NF-kappa B complex. We further demonstrate that Tax induction of nuclear c-Rel expression is activated by the RelA (p65) subunit of NF-kappa B, which activates transcription of the c-rel gene through an intrinsic kappa B enhancer element. In normal cells, the subsequent accumulation of nuclear c-Rel acts to inhibit its own continued production, indicating the presence of an autoregulatory loop. However, the pathologic action HTLV-I Tax leads to the deregulated and sustained nuclear expression of both NF-kappa B and c-Rel, a response that may contribute to HTLV-I-induced T-cell transformation.

197 citations


Journal ArticleDOI
TL;DR: It is shown that the trimerization of LHCII occurs spontaneously and is dependent on the presence of lipids, and both native and reconstituted L HCII trimers exhibit signals in circular dichroism in the visible range, indicating that trimer formation either establishes additional pigment‐pigment interactions or alters pre‐existing interactions.
Abstract: The major light-harvesting complex (LHCII) of photosystem II, the most abundant chlorophyll-containing complex in higher plants, is organized in trimers. In this paper we show that the trimerization of LHCII occurs spontaneously and is dependent on the presence of lipids. LHCII monomers were reconstituted from the purified apoprotein (LHCP), overexpressed in Escherichia coli, and pigments, purified from chloroplast membranes. These synthetic LHCII monomers trimerize in vitro in the presence of a lipid fraction isolated from pea thylakoids. The reconstituted LHCII trimers are very similar to native LHCII trimers in that they are stable in the presence of mild detergents and can be isolated by partially denaturing gel electrophoresis or by centrifugation in sucrose density gradients. Moreover, both native and reconstituted LHCII trimers exhibit signals in circular dichroism in the visible range that are not seen in native or reconstituted LHCII monomers, indicating that trimer formation either establishes additional pigment-pigment interactions or alters pre-existing interactions. Reconstituted LHCII trimers readily form two-dimensional crystals that appear to be identical to crystals of the native complex.

190 citations


Journal ArticleDOI
TL;DR: The present study demonstrates that tumor necrosis factor alpha-induced degradation of I kappa B alpha in human T cells is preceded by its rapid phosphorylation in vivo, and reveals the presence of a second inducible autoregulated inhibitory pathway that helps ensure the rapid but transient action of nuclear NF-kappa B.
Abstract: RelA (p65) functions as the critical transactivating component of the heterodimeric p50-p65 NF-kappa B complex and contains a high-affinity binding site for its cytoplasmic inhibitor, I kappa B alpha. After cellular activation, I kappa B alpha is rapidly degraded in concert with the induced nuclear translocation of NF-kappa B. The present study demonstrates that tumor necrosis factor alpha-induced degradation of I kappa B alpha in human T cells is preceded by its rapid phosphorylation in vivo. However, these effects on I kappa B alpha result in nuclear mobilization of only a fraction of the entire cytoplasmic pool of RelA. Subsequent studies have revealed that (i) cytoplasmic RelA is stably associated not only with I kappa B alpha but also with other ankyrin motif-rich proteins including the products of the NF-kappa B2 (p100) and NF-kappa B1 (p105) genes; (ii) in contrast to RelA-I kappa B alpha, RelA-p100 cytoplasmic complexes are not dissociated following tumor necrosis factor alpha activation; (iii) p100 functions as a potent inhibitor of RelA-mediated transcription in vivo; (iv) the interaction of RelA and p100 involves the conserved Rel homology domain of both proteins but not the nuclear localization signal of RelA, which is required for I kappa B alpha binding; (v) p100 inhibition of RelA function requires the C-terminal ankyrin motif domain, which mediates cytoplasmic retention of RelA; and (vi) as observed with I kappa B alpha, nuclear RelA stimulates p100 mRNA and protein expression. These findings thus reveal the presence of a second inducible autoregulated inhibitory pathway that helps ensure the rapid but transient action of nuclear NF-kappa B.

189 citations


Journal ArticleDOI
TL;DR: Gene sequences highly similar to major histocompatibility complex (Mhc) class I and class II genes were recently recognized as mapping to a site in the genome of the chicken separate from the Mhc class I, class II, and B-G genes of the major histOCompatibility (B) complex.
Abstract: Gene sequences highly similar to major histocompatibility complex (Mhc) class I and class II genes were recently recognized as mapping to a site in the genome of the chicken separate from the Mhc class I, class II, and B-G genes of the major histocompatibility (B) complex. The present study was undertaken to see whether this complex of Mhc-like genes designated as restriction fragment pattern Y (Rfp-Y) might reside in one of three clusters of cosmid clones contained within the molecular map of chicken Mhc genes, since only two of the three clusters can be assigned to the B system. To determine whether the third cluster (cluster II/IV) might contain Rfp-Y, a subclone (18.1) from within cluster II/IV near a polymorphic lectin gene was used to analyze the DNA of families in which Rfp-Y haplotypes are known to be segregating. The restriction fragment polymorphisms revealed by the 18.1 probe were found to segregate in parallel with the restriction fragment polymorphisms defining the Rfp-Y haplotypes, thus establishing the location of Rfp-Y within cosmid cluster II/IV. Two of six Mhc class I genes and two of five Mhc class II genes map to cosmid cluster II/IV, so a substantial fraction of chicken Mhc genes, including at least one that may be expressed, are located in a chromosomal region separate from the B system. In further linkage analyses, Rfp-Y was found to assort independently from more than 400 markers in the present linkage map of the chicken genome.

154 citations


Journal ArticleDOI
TL;DR: An essential role for cooperative interaction between the two NF-kappa B complexes is shown by the requirement for both NF- kappa B sites to mediate E-selectin promoter activation by interleukin-1 and p50/p65 expression.
Abstract: Cytokine-induced expression of the E-selectin gene requires the promoter binding and interaction of the transcription factors NF-kappa B and ATF. Here we have further analyzed the E-selectin promoter and revealed an additional region (nucleotides -140 to -105 [-140/-105]) which is essential in controlling promoter activation by cytokines. We identified high-mobility-group protein I(Y) [HMG-I(Y)] interacting specifically at two sites within this region. We noted that one of the HMG-I(Y)-binding sites overlaps a sequence element (-127/-118) diverging at only one position from the NF-kappa B consensus binding sequence. This led us to ask whether the -127/-118 element represents a second functional NF-kappa B-binding site within the E-selectin promoter. Using specific antisera, we show that p50, p65, and, interestingly, RelB are components of the complex interacting at this site. Mutational analysis of the -127/-118 NF-kappa B site indicates that both NF-kappa B and HMG-I(Y) binding at this site are essential for interleukin-1 induction of the promoter. We demonstrate that the binding affinity of the p50 subunit of NF-kappa B to both NF-kappa B sites within the E-selectin promoter is significantly enhanced by HMG-I(Y). In addition, an essential role for cooperative interaction between the two NF-kappa B complexes is shown by the requirement for both NF-kappa B sites to mediate E-selectin promoter activation by interleukin-1 and p50/p65 expression. We conclude that HMG-I(Y) mediates binding of a distinct NF-kappa B complex at two sites within the E-selectin promoter. Furthermore, a unique cooperativity between these NF-kappa B complexes is essential for induced E-selectin expression. These results suggest mechanisms by which NF-kappa B complexes are involved in specific gene activation.

144 citations


Journal Article
TL;DR: A sizeable minority of the French population is not lavishly supplied with some vitamins, and this situation deserves investigation to see if any deleterious effects are associated with it.
Abstract: The vitamin status of a representative population sample in a French district in the Paris area was assessed using a biochemical and dietary approach. Complete data were obtained for 1039 subjects 6 to 97 years old. Dietary intakes of most vitamins increased up to adolescence and then remained stable or decreased slightly in adult life. Total vitamin intakes were higher in men than in women (except for ascorbic acid), but the vitamin density of the diet was higher in females. Most subjects presented dietary intakes below the French recommended allowances for vitamin B1, B6, C, A and E. A variation in biochemical parameters according to age and sex was observed only for serum concentration of retinol, beta-carotene, vitamin E and C. Multiple regression analysis showed that dietary vitamin intakes were related to the biological status for vitamin B2, B6, C, folates, beta-carotene and vitamin E. Tobacco smoking, alcohol consumption and oral contraceptive were significantly correlated with biological status for several vitamins. While biochemical evidence of severe vitamin deficiency was not observed, a sizeable minority of the French population is not lavishly supplied with some vitamins, and this situation deserves investigation to see if any deleterious effects are associated with it.

132 citations


Journal ArticleDOI
TL;DR: The prevalence of mild hyperhomocysteinemia in young patients with arterial occlusive disease is high and simple and inexpensive therapy with vitamin B6 plus folic acid will normalize homocysteine metabolism, as assessed by the homocy steine plasma level after methionine loading, in virtually all these patients.

124 citations


Journal ArticleDOI
TL;DR: It is found that the MN frequency in young males is significantly and positively correlated with plasma vitamin C levels but negatively correlated with Plasma vitamin B12 status, and in females the only significant correlation was an inverse relationship between MN frequency and the combined folate and vitamin B 12 plasma levels.
Abstract: The cytokinesis-block micronucleus assay is increasingly being applied to the study of spontaneous or induced genetic damage in human lymphocytes, but little is known about dietary and other lifestyle factors that could influence this index. As part of a larger study investigating the role of dietary factors on baseline genetic damage in human lymphocytes from 152 non-smoking females and 113 non-smoking males evenly distributed between the ages of 20 and 87 years, we have measured (a) the micronucleus (MN) frequency and (b) the plasma level of the anti-oxidant vitamins C and E and the B vitamins folic acid and B12. Multiple regression analysis indicated that age (beta value = 0.598, P < 0.0001) was the most important factor influencing the variance of micronucleus frequency in females, while micronutrient levels had no apparent significant effects on genetic damage. In males age was also the predominant factor (beta value = 0.505, P < 0.0001) influencing genetic damage, but vitamin-C level also contributed positively and significantly to the observed MN frequency (beta value = 0.220, P < 0.0228). To avoid the potential confounding effect of collinearity between variables we also performed separate simple regression analysis for each plasma micronutrient in relation to age-adjusted micronucleus frequency; the results from this analysis again showed a significant and positive effect of plasma vitamin C on age-adjusted micronucleus frequency in males only (beta value = 0.188, P = 0.0503), while no effect was observed for the other micronutrients in both sexes. In view of the predominant age effect, we also focused on the data obtained in the youngest age groups of both sexes. In view of the predominant age effect, we also focused on the data obtained in the youngest age groups of both sexes (i.e. 20-30 years olds) and found (a) that the MN frequency in young males is significantly and positively correlated with plasma vitamin C levels (r = 0.823, P < 0.001) but negatively correlated with plasma vitamin B12 status (r = -0.799, P < 0.001) and (b) in females the only significant correlation was an inverse relationship between MN frequency and the combined folate and vitamin B12 plasma levels (r = -0.4632, P < 0.030).(ABSTRACT TRUNCATED AT 400 WORDS)

Journal ArticleDOI
TL;DR: Overt malnutrition was not present, but a deficit of micronutrients, in particular thiamine, cobalamine, folate and sulfur amino acids appears to have been a primary determinant of this epidemic.

Journal ArticleDOI
TL;DR: Omeprazole causes protein-bound vitamin B12 malabsorption, and ingestion of an acidic drink improves protein- bound vitamin B 12 absorption.
Abstract: To investigate the effects of hypochlorhydria and acidic drink ingestion on protein-bound vitamin B12 absorption in elderly subjects.Absorption of protein-bound vitamin B12 was examined in elderly normal subjects (n = 8), and in hypochlorhydric subjects due to omeprazole treatment (n = 8) or with atrophic gastritis (n = 3). Subjects underwent absorption tests of protein-bound vitamin B12 ingested with water, cranberry juice and 0.1 N hydrochloric acid.Protein-bound vitamin B12 absorption was lower in the omeprazole-treated group (0.50%) compared to the normal group (1.21%; p < 0.001). With cranberry juice ingestion, the omeprazole-treated group showed an increase in absorbed protein-bound vitamin B12 (p = 0.025). With dilute hydrochloric acid ingestion, there was a further increase in vitamin B12 absorption (p < 0.001).Omeprazole causes protein-bound vitamin B12 malabsorption, and ingestion of an acidic drink improves protein-bound vitamin B12 absorption.

Journal ArticleDOI
TL;DR: These complexes prevented the reduction of cytochrome c by O2- but were less active than free Mn(II) but were more stable to equimolar EDTA while the Mn(III) desferrioxamine E was stable to a fivefold molar excess of EDTA.

Journal Article
TL;DR: The altered kappa B-binding activity in T cells from RCC patients may impair their capacity to respond normally to various stimuli.
Abstract: Recent data suggest that the poor induction of a T-cell response to human renal cell carcinoma (RCC) may be related to alterations in signal transduction pathways. We report that T cells from RCC patients have two alterations in kappa B motif-specific DNA-binding activity. The first alteration involves the constitutive expression of substantial kappa B-binding activity in nuclear extracts, which was observed in the electrophoretic mobility shift assay. The magnitude of kappa B activity in unstimulated patient T cells was similar to that observed in T cells from normal individuals that had been activated in vitro. On the basis of Western blotting experiments using antibodies to kappa B/Rel family proteins, the kappa B-binding activity constitutively expressed in T cells from RCC patients is composed mostly of the NF-kappa B1 (p50) subunit. The second abnormality in kappa B-binding activity in T cells from these patients is that RelA, a member of the Rel homology family which is part of the normal NF-kappa B complex, was not induced in the nucleus following activation. Western blotting analysis did not detect any RelA in nuclear extracts either before or after stimulation of T cells. The altered kappa B-binding activity in T cells from RCC patients may impair their capacity to respond normally to various stimuli.

Journal ArticleDOI
TL;DR: In vitro experiments with 91 isolated random uvrB mutants show that the helicase motifs V and VI are involved in the induction of ATP hydrolysis in the presence of (damaged) DNA and in the strand-displacement activity of the UvrA2B complex as is observed in a helicase assay.

Journal ArticleDOI
TL;DR: The data suggest that most of the mothers of the subjects studied may have been marginal with respect to vitamins A and E and zinc, and in those with low birthweight babies a higher intake would have improved their nutritional status and possibly the outcome of their pregnancy.

Journal ArticleDOI
TL;DR: The usefulness of the internal standard technique in order to improve the precision of peak area when either the migration time or the injection volume varied was demonstrated.

Journal ArticleDOI
TL;DR: The cytokines interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF alpha) significantly increase the mRNA levels for all three MGSA/GRO isoforms in Hs294T and RPE cells, and both transcriptional and posttranscriptional mechanisms are operational.
Abstract: We have characterized constitutive and cytokine-regulated MGSA/GRO alpha, -beta, and -gamma gene expression in normal retinal pigment epithelial (RPE) cells and a malignant melanoma cell line (Hs294T) to discern the mechanism for MGSA/GRO constitutive expression in melanoma. In RPE cells, constitutive MGSA/GRO alpha, -beta, and -gamma mRNAs are not detected by Northern (RNA) blot analysis although nuclear runoff experiments show that all three genes are transcribed. In Hs294T cells, constitutive MGSA/GRO alpha expression is detectable by Northern blot analysis, and the level of basal MGSA/GRO alpha transcription is 8- to 30-fold higher than in RPE cells. In contrast, in Hs294T cells, basal MGSA/GRO beta and -gamma transcription is only twofold higher than in RPE cells and no beta or gamma mRNA is detected by Northern blot. These data suggest that the constitutive MGSA/GRO alpha mRNA in Hs294T cells is due to increased basal MGSA/GRO alpha gene transcription. The cytokines interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF alpha) significantly increase the mRNA levels for all three MGSA/GRO isoforms in Hs294T and RPE cells, and both transcriptional and posttranscriptional mechanisms are operational. Nuclear runoff assays indicate that in RPE cells, a 1-h IL-1 treatment induces a 10- to 20-fold increase in transcription of MGSA/GRO alpha, -beta and -gamma but only a 2-fold increase in Hs294T cells. Similarly, chloramphenicol acetyltransferase (CAT) reporter gene analysis using the MGSA/GRO alpha, -beta, and -gamma promoter regions demonstrates that IL-1 treatment induces an 8- to 14-fold increase in CAT activity in RPE cells but only a 2-fold increase in Hs294T cells. The effect of deletion or mutation of the MGSA/GRO alpha NF-kappa B element, combined with data from gel mobility shift analyses, indicates that the NF-kappa B p50/p65 heterodimer in RPE cells plays an important role in IL-1- and TNF alpha-enhanced gene transcription. In Hs294T cells, gel shift analyses indicate that IL-1 and TNF alpha induce NF-kappa B complex formation; however, transactivation does not occur, suggesting that subtle differences in the NF-kappa B complexes may result in the inability of the cytokines IL-1 and TNF alpha to activate transcription of the MGSA/GRO genes. IL-1 and TNF alpha posttranscriptionally regulate MGSA/GRO mRNA levels in both cell types. In Hs294T cells, IL-1 increases the half-life of MGSA/GRO alpha from 15 min to 6 h (a 24-fold increase in half-life). These data indicate that IL-1 and TNF alpha transcriptionally and posttranscriptionally regulate MGSA/GRO alpha, -beta, and -gamma mRNA levels in RPE cells, while in Hs294T cells, the major effect of IL-1 and TNF alpha is on mRNA stability.

Journal ArticleDOI
TL;DR: Results of both experiments indicated that nicotinamide was converted rapidly to nicotinic acid by microorganisms in the reticulorumen, which can increase the amount of nicotinIC acid available to the cow; however, some source effects remain to be explained.

Journal ArticleDOI
TL;DR: Viremia levels at 5 and 6 d postinfection were significantly lower in BR2BR2 and B23B23 than in B17B17 genotypes, and challenge with the very virulent RB-1B strain caused 10% and 31% MD in the BR2 BR2 and BR4BR4 chickens, respectively.

Journal Article
TL;DR: Although vitamin treatment permitted a significant improvement in thiamine status, the course of the cardiopathy was not significantly different in CF1 (supplemented) and CF2 (non supplemented) groups.
Abstract: This study compared the thiamine status of 35 elderly hospital inpatients with cardiac failure (CF) with that of 35 elderly inpatients with other diagnoses (Non-CF). The CF group was then randomly allocated to CF1 group (thiamine treatment, 200 mg per day for 7 days), and CF2 group (non supplemented). The effect of the thiamine treatment on the cardiac failure course was examined. Although there was no significant difference in thiamine status between CF and Non-CF groups, 11.5% of the first group against only 6.0% of the second was deficient with the thiamine pyrophosphate stimulation effect (TPPE) test. The same trend was observed, if NYHA functional assessment was taken into account, thiamine deficiency was more frequent in class 4 than in class 3. No significant difference for thiamin status was observed in patients receiving furosemide treatment and those without furosemide treatment. Although vitamin treatment permitted a significant improvement in thiamine status, the course of the cardiopathy was not significantly different in CF1 (supplemented) and CF2 (non supplemented) groups. Whether systematic thiamine supplementation is indicated in CF patients requires further investigation.

Journal ArticleDOI
TL;DR: For the first time it was found that soakings inoculated with C. freundii showed an increased vitamin B12 content, and the concentrations of vitamin B 12 increased significantly.

Journal ArticleDOI
TL;DR: The absence of vitamin-specific effects on performance decrements due to thiamin, riboflavin and vitamin B6 restriction suggests quantitatively similar but non-additive effects of these B-vitamins on mitochondrial metabolism.
Abstract: A combined marginally deficient status of thiamin, riboflavin, vitamin B6 and vitamin C may affect physical performance, but the relative contribution of each vitamin can only be speculated. In a previous study we did not find any effect of restricted intake of vitamin C individually. Therefore, the functional effect of restriction of thiamin, riboflavin or vitamin B6, individually or in conjunction, was investigated.A double-blind, 2 × 2 × 2 complete factorial experiment on the effects of thiamin, riboflavin and vitamin B6 restriction on physical performance was executed with 24 healthy men. During 11 weeks of low vitamin intake, the subjects were given a daily diet of regular food products providing no more than 55% of the Dutch Recommended Dietary Allowances (RDA) for thiamin, riboflavin and vitamin B6. Other vitamins were supplemented at twice the RDA level.In vitamin-restricted subjects, blood vitamin levels, erythrocytic enzyme activities and urinary vitamin excretion decreased and in vitro erythroc...

Journal ArticleDOI
TL;DR: The finding that plants grown with organic fertilizers may contain relatively higher concentrations of this vitamin may have nutritional consequences in that the consumption of these plants by humans would inadvertently increase their intake of thisitamin.
Abstract: A review of the literature showed that plants grown with organic fertilizers often contain higher concentrations of vitamins B1 (thiamin) and B12 (cyanocobalamin) as compared with plants grown with inorganic fertilizers. Since plant roots were recently shown to be able to absorb B1 and B12, it was thus suspected that organic fertilizers (such as manure of diverse sources or sewage sludges which often contain relatively high concentrations of several vitamins) introduce additional vitamins into the soil which in turn leads to increased vitamins in the plants. This possibility was studied by measuring the B12 content in the seeds of soybean and barley and in the leaves of spinach plants grown in soils amended with pure B12 or cow dung (which is naturally rich in B12). The addition of pure B12 or cow dung did not alter the B12 content in the soybean seeds but significantly increased that in the barley kernels and in the spinach leaves. For example, the addition of cow dung at the rate of 10 g kg−1 increased the B12 content in barley kernels by more than threefold (from 2.6 to 9.1 ng g−1 DW) and in spinach leaves by close to twofold (from 6.9 to 17.8 ng g−1 DW). Long-term addition of organic fertilizers to the soil also significantly increased the soil content of this vitamin. Since plants cannot synthesize B12 and thus plant foods are normally fully devoid of (or have very low concentrations of) this vitamin, the finding that plants grown with organic fertilizers may contain relatively higher concentrations of this vitamin may have nutritional consequences in that the consumption of these plants by humans would inadvertently increase their intake of this vitamin. This may be of special benefit to people living by choice or by necessity on strict vegetarian diets who are known to be in danger of B12 deficiency.

Journal ArticleDOI
TL;DR: The hypothesis that qN can occur in the core antenna or Reaction Center of a fraction of PS II units and these units will not exhibit variable fluorescence is put forward to explain the results summarized above.
Abstract: Recently, it has been suggested (Horton et al. 1992) that aggregation of the light-harvesting a-b complex (LHC II) in vitro reflects the processes which occur in vivo during fluorescence induction and related to the major non-photochemical quenching (qE). Therefore the requirement of this chlorophyll a-b containing protein complex to produce qN was investigated by comparison of two barley mutants either lacking (chlorina f2) or depressed (chlorina104) in LHC II to the wild-type and pea leaves submitted to intermittent light (IL) and during their greening in continuous light.

Journal ArticleDOI
TL;DR: It is demonstrated that native envelope glycoproteins of HIV-1, gp160 can induce activation of the transcription factor, NF-κB in CD4 positive T cells and may be involved in biological effects, e.g.,enhanced HIV replication, hypergammaglobulinemia, increased cytokine secretion, hypercellularity in bone marrow and apoptosis.

Journal ArticleDOI
TL;DR: The limited number of subjects in this study demonstrates that ingestion of a prescribed cobalamin-folate supplement and acetaminophen as needed resulted in positive outcomes.
Abstract: Historically diet and arthritis have been cause/effect associated but the idea is controversial with little evidence that specific diet components are effective treatment. This controlled, double-blinded, crossover study reports the effect of folate and cobalamin supplements in 26 humans diagnosed for an average 5.7 years with idiopathic osteoarthritis of the hands who had been medicated by prescribed nonsteroidal anti-inflammatory drugs (NSAID).Subjects entered the study after a 10-day washout period from use of all anti-arthritis drugs, vitamins, and minerals. They were randomly allocated to consume daily 6400 micrograms folate or 6400 micrograms folate plus 20 micrograms cobalamin or lactose placebo each for 2 months within self-selected diets. Pain was to be medicated by acetaminophen as needed, and at the end of each phase they returned for assessment and dispensing of the next treatment. Serum folate and cobalamin, red blood cell folate, blood smears, diet records, standard rheumatology assessment a...

Journal ArticleDOI
TL;DR: Direct effects on supplying blood vessels probably contribute to the oxygenating action of NA in tumours, though the precise mechanism remains obscure.
Abstract: Nicotinamide (NA) is currently entering clinical trials as a radiosensitizer. A major component of its activity is the improvement of tumour oxygenation resulting from a reduction in microregional ischaemia. NA is known to reduce arterial blood pressure in rodents, suggesting a vascular component in its mechanism of action. We have used an ex vivo system to study the direct action of NA on the contractile properties of vascular smooth muscle. Isolated pieces of rat tail artery were internally perfused with Krebs' solution at a constant flow rate so that constriction of the arterial smooth muscle could be measured as an increase in perfusion pressure. Transient vasoconstrictor responses lasting up to 10 min were induced with bolus injections (10 microliters) of phenylephrine, at concentrations ranging from 10(-5) to 10(-2) M, into the internal perfusate whereas a constant increase in vasoconstrictor tone, giving perfusion pressures of 43-84 mmHg, was induced by constantly perfusing with PE (5 x 10(-6) M) or raising the K+ concentration of the Krebs' solution to 122 mM. The addition of NA to the perfusate significantly reduced the size of the transient vasoconstrictor responses in a dose-dependent manner and induced the precontracted vessels to relax. This action of NA could not be blocked either by N omega-nitro-L-arginine methyl ester (L-NAME), indomethacin or propranolol. We conclude that direct effects on supplying blood vessels probably contribute to the oxygenating action of NA in tumours, though the precise mechanism remains obscure.

Book ChapterDOI
01 Jan 1994
TL;DR: In this paper, the authors describe diversity as one of the desirable characteristics of processed muscle foods, and describe processed muscle food as convenient, versatile, and wholesome, and contribute positively to the diet by providing an excellent source of high-quality digestible protein (amount and proportion of essential amino acids), water-soluble vitamins (B vitamins), fat-soluable vitamins (A, D, E, K), minerals (very bioavailable heme iron, zinc), and essential fatty acids).
Abstract: Diversity is one of many very desirable characteristics of processed muscle foods. Processed muscle foods are convenient, versatile, and wholesome, and contribute positively to the diet by providing an excellent source of high-quality digestible protein (amount and proportion of essential amino acids), water-soluble vitamins (B vitamins), fat-soluble vitamins (A, D, E, K), minerals (very bioavailable heme iron, zinc), and essential fatty acids.