OBJECTIVE

To determine whether riboflavin and ultraviolet-A (UVA) corneal crosslinking can be used as an alternative therapy to prevent the progression of keratectasia.

METHODS

Institute for Refractive and Ophthalmic Surgery, Zurich, Switzerland, and a private clinic, Athens, Greece.

METHODS

Corneal crosslinking was performed in 10 patients with formerly undiagnosed forme fruste keratoconus or pellucid marginal corneal degeneration who had laser in situ keratomileusis (LASIK) for myopic astigmatism and subsequently developed iatrogenic keratectasia. Surgery was performed in 1 eye per patient.

RESULTS

Crosslinking induced by riboflavin and UVA arrested and/or partially reversed keratectasia over a postoperative follow-up of up to 25 months as demonstrated by preoperative and postoperative corneal topography and a reduction in maximum keratometric readings.

CONCLUSIONS

Riboflavin-UVA corneal crosslinking increased the biomechanical stability of the cornea and may thus be a therapeutic means to arrest and partially reverse the progression of LASIK-induced iatrogenic keratectasia.

Oxidative degradation of biological substrates by hypochlorous acid has been examined under reaction conditions similar to those found in active phagosomes. Iron sulfur proteins are bleached extremely rapidly, followed in decreasing order by beta-carotene, nucleotides, porphyrins, and heme proteins. Enzymes containing essential cysteine molecules are inactivated with an effectiveness that roughly parallels the nucleophilic reactivities of their sulfhydryl groups. Other compounds, including glucosamines, quinones, riboflavin, and, except for N-chlorination, phospholipids, are unreactive. Rapid irreversible oxidation of cytochromes, adenine nucleotides, and carotene pigments occurs when bacterial cells are exposed to exogenous hypochlorous acid; with Escherichia coli, titrimetric oxidation of cytochrome was found to coincide with loss of aerobic respiration. The occurrence of these cellular reactions implicates hypochlorous acid as a primary microbicide in myeloperoxidase-containing leukocytes; the reactivity patterns observed are consistent with the view that bactericidal action results primarily from loss of energy-linked respiration due to destruction of cellular electron transport chains and the adenine nucleotide pool.

A deficit of mitochondrial energy metabolism may play a role in migraine pathogenesis. We found in a previous open study that high-dose riboflavin was effective in migraine prophylaxis. We now compared riboflavin (400 mg) and placebo in 55 patients with migraine in a randomized trial of 3 months duration. Using an intention-to-treat analysis, riboflavin was superior to placebo in reducing attack frequency (p = 0.005) and headache days (p = 0.012). Regarding the latter, the proportion of patients who improved by at least 50%, i.e. "responders," was 15% for placebo and 59% for riboflavin (p = 0.002) and the number-needed-to-treat for effectiveness was 2.3. Three minor adverse events occurred, two in the riboflavin group (diarrhea and polyuria) and one in the placebo group (abdominal cramps). None was serious. Because of its high efficacy, excellent tolerability, and low cost, riboflavin is an interesting option for migraine prophylaxis and a candidate for a comparative trial with an established prophylactic drug.

The human gut microbiota supplies its host with essential nutrients, including B-vitamins. Using the PubSEED platform, we systematically assessed the genomes of 256 common human gut bacteria for the presence of biosynthesis pathways for eight B-vitamins: biotin, cobalamin, folate, niacin, pantothenate, pyridoxine, riboflavin, and thiamin. On the basis of the presence and absence of genome annotations, we predicted that each of the eight vitamins was produced by 40-65% of the 256 human gut microbes. The distribution of synthesis pathways was diverse; some genomes had all eight biosynthesis pathways, whereas others contained no de novo synthesis pathways. We compared our predictions to experimental data from 16 organisms and found 88% of our predictions to be in agreement with published data. In addition, we identified several pairs of organisms whose vitamin synthesis pathway pattern complemented those of other organisms. This analysis suggests that human gut bacteria actively exchange B-vitamins among each other, thereby enabling the survival of organisms that do not synthesize any of these essential cofactors. This result indicates the co-evolution of the gut microbes in the human gut environment. Our work presents the first comprehensive assessment of the B-vitamin synthesis capabilities of the human gut microbiota. We propose that in addition to diet, the gut microbiota is an important source of B-vitamins, and that changes in the gut microbiota composition can severely affect our dietary B-vitamin requirements.

Household food insecurity constrains food selection, but whether the dietary compromises associated with this problem heighten the risk of nutrient inadequacies is unclear. The objectives of this study were to examine the relationship between household food security status and adults' and children's dietary intakes and to estimate the prevalence of nutrient inadequacies among adults and children, differentiating by household food security status. We analyzed 24-h recall and household food security data for persons aged 1-70 y from the 2004 Canadian Community Health Survey (cycle 2.2). The relationship between adults' and children's nutrient and food intakes and household food security status was assessed using regression analysis. Estimates of the prevalence of inadequate nutrient intakes by food security status and age/sex group were calculated using probability assessment methods. Poorer dietary intakes were observed among adolescents and adults in food-insecure households and many of the differences by food security status persisted after accounting for potential confounders in multivariate analyses. Higher estimated prevalences of nutrient inadequacy were apparent among adolescents and adults in food-insecure households, with the differences most marked for protein, vitamin A, thiamin, riboflavin, vitamin B-6, folate, vitamin B-12, magnesium, phosphorus, and zinc. Among children, few differences in dietary intakes by household food security status were apparent and there was little indication of nutrient inadequacy. This study indicates that for adults and, to some degree, adolescents, food insecurity is associated with inadequate nutrient intakes. These findings highlight the need for concerted public policy responses to ameliorate household food insecurity.

Mucosal-associated invariant T (MAIT) cells are abundant in humans and recognize conserved bacterial antigens derived from riboflavin precursors, presented by the non-polymorphic MHC class I-like molecule MR1. Here we show that human MAIT cells are remarkably oligoclonal in both the blood and liver, display high inter-individual homology and exhibit a restricted length CDR3β domain of the TCRVβ chain. We extend this analysis to a second sub-population of MAIT cells expressing a semi-invariant TCR conserved between individuals. Similar to 'conventional' MAIT cells, these lymphocytes react to riboflavin-synthesizing microbes in an MR1-restricted manner and infiltrate solid tissues. Both MAIT cell types release Th0, Th1 and Th2 cytokines, and sCD40L in response to bacterial infection, show cytotoxic capacity against infected cells and promote killing of intracellular bacteria, thus suggesting important protective and immunoregulatory functions of these lymphocytes.

Mucosal-associated invariant T (MAIT) cells are an innate-like T-cell population restricted by the non-polymorphic, major histocompatibility complex class I-related protein 1, MR1. MAIT cells are activated by a broad range of bacteria through detection of riboflavin metabolites bound by MR1, but their direct cytolytic capacity upon recognition of cognate target cells remains unclear. We show that resting human MAIT cells are uniquely characterized by a lack of granzyme (Gr) B and low perforin expression, key granule proteins required for efficient cytotoxic activity, but high levels of expression of GrA and GrK. Bacterial activation of MAIT cells rapidly induced GrB and perforin, licensing these cells to kill their cognate target cells. Using a novel flow cytometry-based killing assay, we show that licensed MAIT cells, but not ex vivo MAIT cells from the same donors, can efficiently kill Escherichia coli-exposed B-cell lines in an MR1- and degranulation-dependent manner. Finally, we show that MAIT cells are highly proliferative in response to antigenic and cytokine stimulation, maintaining high expression of GrB, perforin, and GrA, but reduced expression of GrK following antigenic proliferation. The tightly regulated cytolytic capacity of MAIT cells may have an important role in the control of intracellular bacterial infections, such as Mycobacterium tuberculosis.

Blue native-polyacrylamide gel electrophoresis is a powerful technique that enables the separation of intact multi-subunit complexes. However, positive identification of particular enzymes generally requires further separation in a second dimension on a denaturing polyacrylamide gel. Histochemical staining is widely used to demonstrate enzyme activities in tissues, including oxidative phosphorylation enzymes. In this report, we demonstrate that the two techniques can be combined to quantify in situ mitochondrial enzymes, separated on nondenaturing polyacrylamide gels. The method gives quantitative results with human skeletal muscle as well as heart that contains higher mitochondrial numbers. Comparison of muscle from patients with oxidative phosphorylation enzyme deficiencies, such as those of two riboflavin-responsive patients, before and after vitamin treatment, gives results in agreement with those obtained by analyzing the activity of the mitochondrial enzymes in muscle homogenates.

Multiple acyl-CoA dehydrogenation deficiency (MADD) is a disorder of fatty acid, amino acid and choline metabolism that can result from defects in two flavoproteins, electron transfer flavoprotein (ETF) or ETF: ubiquinone oxidoreductase (ETF:QO). Some patients respond to pharmacological doses of riboflavin. It is unknown whether these patients have defects in the flavoproteins themselves or defects in the formation of the cofactor, FAD, from riboflavin. We report 15 patients from 11 pedigrees. All the index cases presented with encephalopathy or muscle weakness or a combination of these symptoms; several had previously suffered cyclical vomiting. Urine organic acid and plasma acyl-carnitine profiles indicated MADD. Clinical and biochemical parameters were either totally or partly corrected after riboflavin treatment. All patients had mutations in the gene for ETF:QO. In one patient, we show that the ETF:QO mutations are associated with a riboflavin-sensitive impairment of ETF:QO activity. This patient also had partial deficiencies of flavin-dependent acyl-CoA dehydrogenases and respiratory chain complexes, most of which were restored to control levels after riboflavin treatment. Low activities of mitochondrial flavoproteins or respiratory chain complexes have been reported previously in two of our patients with ETF:QO mutations. We postulate that riboflavin-responsive MADD may result from defects of ETF:QO combined with general mitochondrial dysfunction. This is the largest collection of riboflavin-responsive MADD patients ever reported, and the first demonstration of the molecular genetic basis for the disorder.

Indigenous Peoples globally are part of the nutrition transition. They may be among the most extreme for the extent of dietary change experienced in the last few decades. In this paper, we report survey data from 44 representative communities from 3 large cultural areas of the Canadian Arctic: the Yukon First Nations, Dene/Métis, and Inuit communities. Dietary change was represented in 2 ways: 1) considering the current proportion of traditional food (TF) in contrast to the precontact period (100% TF); and 2) the amount of TF consumed by older vs. younger generations. Total diet, TF, and BMI data from adults were investigated. On days when TF was consumed, there was significantly less (P < 0.01) fat, carbohydrate, and sugar in the diet, and more protein, vitamin A, vitamin D, vitamin E, riboflavin, vitamin B-6, iron, zinc, copper, magnesium, manganese, phosphorus, potassium, and selenium. Vitamin C and folate, provided mainly by fortified food, and fiber were higher (P < 0.01) on days without TF for Inuit. Only 10-36% of energy was derived from TF; adults>> 40 y old consistently consumed more (P < 0.05) TF than those younger. Overall obesity (BMI>> or = 30 kg/m(2)) of Arctic adults exceeded all-Canadian rates. Measures to improve nutrient-dense market food (MF) availability and use are called for, as are ways to maintain or increase TF use.

The authors report the results of a dietary survey of 38,121 Iowa women, 55-69 years of age in 1986, based on a semiquantitative food frequency questionnaire previously tested among Boston-area women aged 34-59 years. The Iowa women, compared with the younger Boston-area women, consumed a similar amount of calories (1,767 vs. 1,844 kcal) and a similar amount of total calories from fat (35 vs. 37%) but had markedly greater intake of the following micronutrients after including supplement use: iron (+18%), calcium (+33%), vitamin A (+43%), riboflavin (+46%), thiamine (+50%), and pyridoxine (+122%). The reproducibility of the questionnaire was examined in two more administrations to 44 of the Iowa women in January and June of 1988. Reproducibility was highest for alcohol (Pearson's r = 0.99), caffeine (r = 0.95), and vitamin E (r = 0.90) and lowest for sucrose (r = 0.53), polyunsaturated fat (r = 0.56), and iron (r = 0.59). Micronutrient intakes were generally more reproducible than macronutrient intakes. The agreement between the June 1988 questionnaire and the average of five 24-hour dietary recalls was also assessed in the 44 subjects. The median correlations of energy-adjusted intake were as follows: for macronutrients, r = 0.45; for micronutrients without supplements, r = 0.33; and for micronutrients with supplements, r = 0.64. This food frequency questionnaire appears to be reasonably reproducible and accurate, so that its use may be extended to epidemiologic studies of older women with a broad range of socioeconomic backgrounds.

Riboswitches are structures that form in mRNA and regulate gene expression in bacteria. Unlike other known RNA regulatory structures, they are directly bound by small ligands. The mechanism by which gene expression is regulated involves the formation of alternative structures that, in the repressing conformation, cause premature termination of transcription or inhibition of translation initiation. Riboswitches regulate several metabolic pathways including the biosynthesis of vitamins (e.g. riboflavin, thiamin and cobalamin) and the metabolism of methionine, lysine and purines. Candidate riboswitches have also been observed in archaea and eukaryotes. The taxonomic diversity of genomes containing riboswitches and the diversity of molecular mechanisms of regulation, in addition to the fact that direct interaction of riboswitches with their effectors does not require additional factors, suggest that riboswitches represent one of the oldest regulatory systems.

BACKGROUND

It has been suggested that elevated total plasma homocysteine levels are associated with the risk of venous thrombosis.

OBJECTIVE

To assess the relationship of homocysteine and the MTHFR 677TT genotype and the risk of venous thrombosis by conducting a meta-analysis of all relevant studies.

METHODS

Studies (case-control or nested case-control) were identified by searches of electronic literature for relevant reports published before July 2003 on homocysteine and the MTHFR 677TT genotype and venous thrombosis as an end-point, by hand-searching reference lists of original articles (including meta-analyses) on this topic and by contact with investigators in the field.

METHODS

A meta-analysis of 24 retrospective (n = 3289 cases) and three prospective studies (n = 476 cases) was carried out to examine the association of homocysteine with venous thrombosis. A meta-analysis of 53 studies (n = 8364 cases) of the MTHFR 677TT genotype (that increases homocysteine) was carried out to assess if this association is causal.

RESULTS

A 5 micromol L(-1) higher measured homocysteine level was associated with a 27% (95% CI: 1-59) higher risk of venous thrombosis in prospective studies and a 60% (95% CI: 10-134) higher risk in retrospective studies. The 677TT genotype was associated with a 20% (95% CI: 8-32) higher risk of venous thrombosis compared with the 677CC genotype. In contrast with non-American studies, the 677TT genotype had no effect on venous thrombosis in North America, due probably to the higher intake of folate and riboflavin in North America.

CONCLUSIONS

This meta-analysis of prospective and retrospective studies demonstrates a modest association of homocysteine with venous thrombosis. The elevated risk associated with the MTHFR 677TT genotype provides some support for causality.

Insects, a traditional food in many parts of the world, are highly nutritious and especially rich in proteins and thus represent a potential food and protein source. A compilation of 236 nutrient compositions in addition to amino acid spectra and fatty acid compositions as well as mineral and vitamin contents of various edible insects as derived from literature is given and the risks and benefits of entomophagy are discussed. Although the data were subject to a large variation, it could be concluded that many edible insects provide satisfactorily with energy and protein, meet amino acid requirements for humans, are high in MUFA and/or PUFA, and rich in several micronutrients such as copper, iron, magnesium, manganese, phosphorous, selenium, and zinc as well as riboflavin, pantothenic acid, biotin, and in some cases folic acid. Liabilities of entomophagy include the possible content of allergenic and toxic substances as well as antinutrients and the presence of pathogens. More data are required for a thorough assessment of the nutritional potential of edible insects and proper processing and decontamination methods have to be developed to ensure food safety.

OBJECTIVE

Dental caries is a common, chronic disease of childhood. The impact of contemporary changes in beverage patterns, specifically decreased milk intakes and increased 100% juice and soda pop intakes, on dental caries in young children is unknown. We describe associations among caries experience and intakes of dairy foods, sugared beverages, and nutrients and overall diet quality in young children.

METHODS

Subjects (n = 642) are members of the Iowa Fluoride Study, a cohort followed from birth. Food and nutrient intakes were obtained from 3-day diet records analyzed at 1 (n = 636), 2 (n = 525), 3 (n = 441), 4 (n = 410), and 5 (n = 417) years and cumulatively for 1 through 5 (n = 396) years of age. Diet quality was defined by nutrient adequacy ratios (NARs) and calculated as the ratio of nutrient intake to Recommended Dietary Allowance/Adequate Intake. Caries were identified during dental examinations by 2 trained and calibrated dentists at 4 to 7 years of age. Examinations were visual, but a dental explorer was used to confirm questionable findings. Caries experience was assessed at both the tooth and the surface levels. Data were analyzed using SAS. The Wilcoxon rank sum test was used to compare food intakes, nutrient intakes, and NARs of subjects with and without caries experience. Logistic and Tobit regression analyses were used to identify associations among diet variables and caries experience and to develop models to predict caries experience. Not all relationships between food intakes and NARs and caries experience were linear; therefore, categorical variables were used to develop models to predict caries experience. Food and beverage intakes were categorized as none, low, and high intakes, and NARs were categorized as inadequate, low adequate, and high adequate.

RESULTS

Subjects with caries had lower median intakes of milk at 2 and 3 years of age than subjects without caries. Subjects with caries had higher median intakes of regular (sugared) soda pop at 2, 3, 4, and 5 years and for 1 through 5 years; regular beverages from powder at 1, 4, and 5 years and for 1 through 5 years; and total sugared beverages at 4 and 5 years than subjects without caries. Logistic regression models were developed for exposure variables at 1, 2, 3, 4, and 5 years and for 1 through 5 years to predict any caries experience at 4 to 7 years of age. Age at dental examination was retained in models at all ages. Children with 0 intake (vs low and high intakes) of regular beverages from powder at 1 year, regular soda pop at 2 and 3 years, and sugar-free beverages from powder at 5 years had a decreased risk of caries experience. High intakes of regular beverages from powder at 4 and 5 years and for 1 through 5 years and regular soda pop at 5 years and for 1 through 5 years were associated with significantly increased odds of caries experience relative to subjects with none or low intakes. Low (vs none or high) intakes of 100% juice at 5 years were associated with decreased caries experience. In general, inadequate intakes (vs low adequate or high adequate intakes) of nutrients (eg, riboflavin, copper, vitamin D, vitamin B(12)) were associated with increased caries experience and low adequate intakes (vs inadequate or high adequate intakes) of nutrients (eg, vitamin B(12), vitamin C) were associated with decreased caries experience. An exception was vitamin E; either low or high adequate intakes were associated with increased caries experience at various ages. Multivariable Tobit regression models were developed for 1- through 5-year exposure variables to predict the number of tooth surfaces with caries experience at 4 to 7 years of age. Age at dental examination showed a significant positive association and fluoride exposure showed a significant negative association with the number of tooth surfaces with caries experience in the final model. Low intakes of nonmilk dairy foods (vs high intakes; all subjects had some nonmilk dairy intakes) and high adequate intakes of vitamin C (vs inadequate and low adequate intakes) were associated with fewer tooth surfaces having caries experience. High intakes of regular soda pop (vs none and low intakes) were associated with more tooth surfaces having caries experience.

CONCLUSIONS

Results of our study suggest that contemporary changes in beverage patterns, particularly the increase in soda pop consumption, have the potential to increase dental caries rates in children. Consumption of regular soda pop, regular powdered beverages, and, to a lesser extent, 100% juice was associated with increased caries risk. Milk had a neutral association with caries. Associations between different types of sugared beverages and caries experience were not equivalent, which could be attributable to the different sugar compositions of the beverages or different roles in the diet. Our data support contemporary dietary guidelines for children: consume 2 or more servings of dairy foods daily, limit intake of 100% juice to 4 to 6 oz daily, and restrict other sugared beverages to occasional use. Pediatricians, pediatric nurse practitioners, and dietitians are in a position to support pediatric dentists in providing preventive guidance to parents of young children.

Reactive oxygen species (ROS) produced by NADPH oxidase function as defence and signalling molecules related to innate immunity and various cellular responses. The activation of NADPH oxidase in response to plasma membrane receptor activation depends on the phosphorylation of cytoplasmic oxidase subunits, their translocation to membranes and the assembly of all NADPH oxidase components. Tumour necrosis factor (TNF) is a prominent stimulus of ROS production, but the molecular mechanisms by which TNF activates NADPH oxidase are poorly understood. Here we identify riboflavin kinase (RFK, formerly known as flavokinase) as a previously unrecognized TNF-receptor-1 (TNFR1)-binding protein that physically and functionally couples TNFR1 to NADPH oxidase. In mouse and human cells, RFK binds to both the TNFR1-death domain and to p22(phox), the common subunit of NADPH oxidase isoforms. RFK-mediated bridging of TNFR1 and p22(phox) is a prerequisite for TNF-induced but not for Toll-like-receptor-induced ROS production. Exogenous flavin mononucleotide or FAD was able to substitute fully for TNF stimulation of NADPH oxidase in RFK-deficient cells. RFK is rate-limiting in the synthesis of FAD, an essential prosthetic group of NADPH oxidase. The results suggest that TNF, through the activation of RFK, enhances the incorporation of FAD in NADPH oxidase enzymes, a critical step for the assembly and activation of NADPH oxidase.

SEVEN VITAMINS HAVE TO DATE PROVED ESSENTIAL FOR THE SURVIVAL AND MULTIPLICATION OF A MOUSE FIBROBLAST (STRAIN L) AND A HUMAN CARCINOMA CELL (STRAIN HELA) IN TISSUE CULTURE: choline, folic acid, nicotinamide, pantothenic acid, pyridoxal, riboflavin, and thiamin. It was necessary to cultivate the cells for 5 to 15 days in a medium lacking the specific vitamin before the deficiency became apparent in the cessation of multiplication and the development of specific cytopathogenic effects. In their early stages these changes could be reversed by the addition of the missing vitamin, an in vitro, "cure" of a vitamin deficiency. The maximally effective concentrations were in the range 10(7) to 10(8) gm. per ml. The probability that additional vitamins not demonstrably essential under the conditions of the present experiments are nevertheless required for survival and growth is discussed in the text.

The biosynthesis of several protein cofactors is subject to feedback regulation by riboswitches. Flavin mononucleotide (FMN)-specific riboswitches, also known as RFN elements, direct expression of bacterial genes involved in the biosynthesis and transport of riboflavin (vitamin B(2)) and related compounds. Here we present the crystal structures of the Fusobacterium nucleatum riboswitch bound to FMN, riboflavin and antibiotic roseoflavin. The FMN riboswitch structure, centred on an FMN-bound six-stem junction, does not fold by collinear stacking of adjacent helices, typical for folding of large RNAs. Rather, it adopts a butterfly-like scaffold, stapled together by opposingly directed but nearly identically folded peripheral domains. FMN is positioned asymmetrically within the junctional site and is specifically bound to RNA through interactions with the isoalloxazine ring chromophore and direct and Mg(2+)-mediated contacts with the phosphate moiety. Our structural data, complemented by binding and footprinting experiments, imply a largely pre-folded tertiary RNA architecture and FMN recognition mediated by conformational transitions within the junctional binding pocket. The inherent plasticity of the FMN-binding pocket and the availability of large openings make the riboswitch an attractive target for structure-based design of FMN-like antimicrobial compounds. Our studies also explain the effects of spontaneous and antibiotic-induced deregulatory mutations and provided molecular insights into FMN-based control of gene expression in normal and riboflavin-overproducing bacterial strains.

The α-proteobacterium Wolbachia is probably the most prevalent, vertically transmitted symbiont on Earth. In contrast with its wide distribution in arthropods, Wolbachia is restricted to one family of animal-parasitic nematodes, the Onchocercidae. This includes filarial pathogens such as Onchocerca volvulus, the cause of human onchocerciasis, or river blindness. The symbiosis between filariae and Wolbachia is obligate, although the basis of this dependency is not fully understood. Previous studies suggested that Wolbachia may provision metabolites (e.g., haem, riboflavin, and nucleotides) and/or contribute to immune defense. Importantly, Wolbachia is restricted to somatic tissues in adult male worms, whereas females also harbor bacteria in the germline. We sought to characterize the nature of the symbiosis between Wolbachia and O. ochengi, a bovine parasite representing the closest relative of O. volvulus. First, we sequenced the complete genome of Wolbachia strain wOo, which revealed an inability to synthesize riboflavin de novo. Using RNA-seq, we also generated endobacterial transcriptomes from male soma and female germline. In the soma, transcripts for membrane transport and respiration were up-regulated, while the gonad exhibited enrichment for DNA replication and translation. The most abundant Wolbachia proteins, as determined by geLC-MS, included ligands for mammalian Toll-like receptors. Enzymes involved in nucleotide synthesis were dominant among metabolism-related proteins, whereas the haem biosynthetic pathway was poorly represented. We conclude that Wolbachia may have a mitochondrion-like function in the soma, generating ATP for its host. Moreover, the abundance of immunogenic proteins in wOo suggests a role in diverting the immune system toward an ineffective antibacterial response.

Comparative analysis of genes, operons and regulatory elements was applied to the lysine biosynthetic pathway in available bacterial genomes. We report identification of a lysine-specific RNA element, named the LYS element, in the regulatory regions of bacterial genes involved in biosynthesis and transport of lysine. Similarly to the previously described RNA regulatory elements for three vitamins (riboflavin, thiamin and cobalamin), purine and methionine regulons, this regulatory RNA structure is highly conserved on the sequence and structural levels. The LYS element includes regions of lysine-constitutive mutations previously identified in Escherichia coli and Bacillus subtilis. A possible mechanism of the lysine-specific riboswitch is similar to the previously defined mechanisms for the other metabolite-specific riboswitches and involves either transcriptional or translational attenuation in various groups of bacteria. Identification of LYS elements in Gram-negative gamma-proteobacteria, Gram-positive bacteria from the Bacillus/Clostridium group, and Thermotogales resulted in description of the previously uncharacterized lysine regulon in these bacterial species. Positional analysis of LYS elements led to identification of a number of new candidate lysine transporters, namely LysW, YvsH and LysXY. Finally, the most likely candidates for genes of lysine biosynthesis missing in Gram- positive bacteria were identified using the genome context analysis.

Riboflavin, which improves energy metabolism similarly to coenzyme Q10 (CoQ10), is effective in migraine prophylaxis. We compared CoQ10 (3 x 100 mg/day) and placebo in 42 migraine patients in a double-blind, randomized, placebo-controlled trial. CoQ10 was superior to placebo for attack-frequency, headache-days and days-with-nausea in the third treatment month and well tolerated; 50%-responder-rate for attack frequency was 14.4% for placebo and 47.6% for CoQ10 (number-needed-to-treat: 3). CoQ10 is efficacious and well tolerated.

Drugs are usually given orally. They are not absorbed to any extent from the stomach but may be absorbed very rapidly from the small intestine. Thus factors influencing the rate of gastric emptying may alter the rate of absorption of most if not all orally administered drugs. Food, hormones, posture, peritoneal irritation, severe pain, gastric ulcer, diabetes and other metabolic diseases, as well as drugs such as alcohol, anticholinergics, narcotic analgesics, ganglion blocking drugs, antacids and metoclopramide all influence the rate of gastric emptying and they will, in turn, change the rate of absorption of another drug. In most instances, increasing the rate of gastric emptying and gastro-intestinal motility increases the rate of absorption of a drug but, for digoxin and riboflavin, increased gastrointestinal motility is associated with a decrease in the rate of absorption. Delayed drug absorption due to altered gastric emptying usually results in therapeutic failure, especially if the drug has a short biological half-life. At present it is not possible to predict accurately the magnitude and clinical relevance of all drug absorption interactions.

The purpose of this study was to examine the consequences associated with food insecurity for the nutritional and health status of the elderly in the United STATES: The data analyzed were from the Third National Health and Nutrition Examination Survey (1988-1994) and the Nutrition Survey of the Elderly in New York State (1994). Multiple logistic and linear regression analyses were used to assess the extent to which food-insecure elderly were likely to have lower nutrient intake, skinfold thickness, self-reported health status and higher nutritional risk. Regardless of food insecurity status, older people consumed less than the recommended dietary allowance for eight nutrients. Food-insecure elderly persons had significantly lower intakes of energy, protein, carbohydrate, saturated fat, niacin, riboflavin, vitamins B-6 and B-12, magnesium, iron and zinc, as well as lower skinfold thickness. In addition, food-insecure elderly persons were 2.33 (95% confidence interval: 1.73-3.14) times more likely to report fair/poor health status and had higher nutritional risk. These results indicate that food-insecure elderly persons have poorer dietary intake, nutritional status and health status than do food-secure elderly persons. It is necessary to ensure the nutritional well-being of all elderly persons who are at nutritional and health risk, including those who are food insecure and have even poorer nutritional and health status than those who are food secure.

The hypoglycemic and hypolipidemic effects of Lycium barbarum fruit water decoction, crude polysaccharide extracts (crude LBP), and purified polysaccharide fractions (LBP-X) in alloxan-induced diabetic or hyperlipidemic rabbits were investigated through designed sequential trials and by measuring blood glucose and serum lipid parameters. Total antioxidant capacity was also assessed using trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assay. It was found that the three Lycium barbarum fruit extracts/fractions could significantly reduce blood glucose levels and serum total cholesterol (TC) and triglyceride (TG) concentrations and at same time markedly increase high density lipoprotein cholesterol (HDL-c) levels after 10 days treatment in tested rabbits, indicating that there were substantial hypoglycemic and hypolipidemic effects. Hypoglycemic effect of LBP-X was more significant than those of water decoction and crude LBP, but its hypolipidemic effect seemed to be weaker. Total antioxidant capacity assay showed that all three Lycium barbarum extracts/fractions possessed antioxidant activity. However, water and methanolc fruit extracts and crude polysaccharide extracts exhibited stronger antioxidant activity than purified polysaccharide fractions because crude extracts were identified to be rich in antioxidants (e.g., carotenoids, riboflavin, ascorbic acid, thiamine, nicotinic acid). Lycium barbarum polysaccharides (glycocojugates), containing several monosaccharides and 17 amino acids, were major bioactive constituents of hypoglycemic effect. Both polysaccharides and vitamin antioxidants from Lycium barbarum fruits were possible active principles of hypolipidemic effect.