Maternal vitamin D status in pregnancy and adverse pregnancy outcomes in a group at high risk for pre-eclampsia.

OBJECTIVE: To determine in a group of pregnant women if vitamin D status, based on serum 25-hydroxyvitamin D (25OHD) concentration, was associated with a subsequent risk of pre-eclampsia or adverse pregnancy outcomes. DESIGN: Prospective cohort study. SETTING: Vancouver, British Columbia, Canada (49°N). POPULATION: Women attending a specialist antenatal clinic because of clinical or biochemical risk factors for pre-eclampsia (n = 221). METHODS: Serum 25OHD concentration measured between 10 and 20 weeks of gestation. MAIN OUTCOME MEASURES: Pre-eclampsia and composite adverse pregnancy outcomes. RESULTS: Of the women, 78% were vitamin D insufficient (25OHD <75 nmol/l) and 53% were vitamin D deficient (25OHD <50 nmol/l). There was no difference in the rates of pre-eclampsia, gestational hypertension, preterm birth or composite adverse pregnancy outcomes by 25OHD concentration. CONCLUSIONS: Vitamin D deficiency and insufficiency were common in a group of women at high risk of pre-eclampsia; however, it was not associated with subsequent risk of an adverse pregnancy outcome.

Bacterial diversity of the digestive gland of Sydney rock oysters, Saccostrea glomerata infected with the paramyxean parasite, Marteilia sydneyi.

AIMS: To determine whether the infestation by the protozoan paramyxean parasite, Marteilia sydneyi, changes the bacterial community of the digestive gland of Sydney rock oysters, Saccostrea glomerata. METHODS AND RESULTS: Six 16S rDNA clone libraries were established from three M. sydneyi-infected and three un-infected oysters. Restriction enzyme analysis followed by sequencing representative clones revealed a total of 23 different operational taxonomic units (OTUs) in un-infected oysters, comprising the major phyla: Firmicutes, Proteobacteria, Cyanobacteria and Spirocheates, where the clone distribution was 44, 36, 7 and 5%, respectively. Close to half of the OTUs are not closely related to any other hitherto determined sequence. In contrast, S. glomerata infected by M. sydneyi had only one OTU present in the digestive gland. Phylogenetic analysis of the 16S rDNA sequence reveals that this dominant OTU, belonging to the alpha-Proteobacteria, is closely related to a Rickettsiales-like prokaryote (RLP). CONCLUSIONS: The microbiota of the digestive gland of Sydney rock oysters is changed by infection by M. sydneyi, becoming dominated by a RLP, and generally less diverse. The bacterial community of un-infected S. glomerata differs from previous studies in that we identified the dominant taxa as Firmicutes and alpha-Proteobacteria, rather than heterotrophic gamma-Proteobacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first culture-independent study of the microbiota of the digestive glands of edible oysters to the species level. The commercial viability of the Sydney rock oyster industry in Australia is currently threatened by Queensland Unknown disease and the changes in the bacterial community of S. glomerata corresponding with infection by M. sydneyi sheds further light on the link between parasite infection and mortality in this economically damaging disease.

Association between quantitative measures of skin color and plasma 25-hydroxyvitamin D.

UNLABELLED: We examined the relationship between vitamin D and skin color measured by reflectance colorimetry at an exposed and un-exposed site in 321 people. Exposed but not unexposed skin color was associated with better vitamin D status. Sun-exposure was more important than natural skin color in determining vitamin D status in our population. INTRODUCTION: Vitamin D is obtained through UV synthesis in the skin where melanin limits its synthesis. Ethnicity is often used as a proxy for skin color, but skin color varies considerably. The relation between quantitative measures of skin color and plasma 25-hydroxyvitamin D (25OHD) concentration has not been well described. METHODS: The aim of this study was to determine the association between constitutive (natural) and sun-induced skin color and 25OHD in a group of Pacific People (n = 87) and Europeans (n = 255) living in NZ (46 degrees S) in summer. Plasma 25OHD was determined and sun-induced (outer fore-arm) and constitutive (upper inner-arm) measured by reflectance colorimetry. RESULTS: Mean (SD) 25OHD was significantly higher in Europeans than Pacific People, 88 (31) nmol/L vs. 75 (34) nmol/L, respectively. Based on constitutive skin color, 35% of participants were very light, 45% light, 16% intermediate, 4% tanned, and 0% brown or dark. Skin color at the forearm but not constitutive skin color was a significant predictor of 25OHD. Each 10 degrees lower skin color value at the forearm (more tanning) was associated with a 5 nmol/L higher 25OHD (P < 0.001). CONCLUSIONS: Tanning but not natural skin color was an important determinant of 25OHD. Further study is needed in a population with a higher proportion of darker skin people.

Vitamin D status and its association with parathyroid hormone concentrations in women of child-bearing age living in Jakarta and Kuala Lumpur.

OBJECTIVE: To describe the vitamin D status of women living in two Asian cities,--Jakarta (6 degrees S) and Kuala-Lumpur (2 degrees N), to examine the association between plasma 25-hydroxyvitamin D and parathyroid hormone (PTH) concentrations, and to determine a threshold for plasma 25-hydroxyvitamin D above which there is no further suppression of PTH. Also, to determine whether dietary calcium intake influences the relationship between PTH and 25-hydroxyvitamin D. DESIGN: Cross-sectional. SETTING: Jakarta, Indonesia and Kuala Lumpur, Malaysia. PARTICIPANTS: A convenience sample of 504 non-pregnant women 18-40 years. MAIN MEASURES: Plasma 25-hydroxyvitamin D and PTH. RESULTS: The mean 25-hydroxyvitamin D concentration was 48 nmol/l. Less than 1% of women had a 25-hydroxyvitamin D concentration indicative of vitamin D deficiency (<17.5 nmol/l); whereas, over 60% of women had a 25-hydroxyvitamin D concentration indicative of insufficiency (<50 nmol/l). We estimate that 52 nmol/l was the threshold concentration for plasma 25-hydroxyvitamin D above which no further suppression of PTH occurred. Below and above this concentration the slopes of the regression lines were -0.18 (different from 0; P=0.003) and -0.01 (P=0.775), respectively. The relation between vitamin D status and parathyroid hormone concentration did not differ between women with low, medium or high calcium intakes (P=0.611); however, even in the highest tertile of calcium intake, mean calcium intake was only 657 mg/d. CONCLUSION: On the basis of maximal suppression of PTH we estimate an optimal 25-hydroxyvitamin D concentration of approximately 50 nmol/l. Many women had a 25-hydroxyvitamin D below this concentration and may benefit from improved vitamin D status.

Glycemic index and glycemic load: measurement issues and their effect on diet-disease relationships.

Glycemic index (GI) describes the blood glucose response after consumption of a carbohydrate containing test food relative to a carbohydrate containing reference food, typically glucose or white bread. GI was originally designed for people with diabetes as a guide to food selection, advice being given to select foods with a low GI. The amount of food consumed is a major determinant of postprandial hyperglycemia, and the concept of glycemic load (GL) takes account of the GI of a food and the amount eaten. More recent recommendations regarding the potential of low GI and GL diets to reduce the risk of chronic diseases and to treat conditions other than diabetes, should be interpreted in the light of the individual variation in blood glucose levels and other methodological issues relating to measurement of GI and GL. Several factors explain the large inter- and intra-individual variation in glycemic response to foods. More reliable measurements of GI and GL of individual foods than are currently available can be obtained by studying, under standard conditions, a larger number of subjects than has typically been the case in the past. Meta-analyses suggest that foods with a low GI or GL may confer benefit in terms of glycemic control in diabetes and lipid management. However, low GI and GL foods can be energy dense and contain substantial amounts of sugars or undesirable fats that contribute to a diminished glycemic response. Therefore, functionality in terms of a low glycemic response alone does not necessarily justify a health claim. Most studies, which have demonstrated health benefits of low GI or GL involved naturally occurring and minimally processed carbohydrate containing cereals, vegetables and fruit. These foods have qualities other than their immediate impact on postprandial glycemia as a basis to recommend their consumption. When the GI or GL concepts are used to guide food choice, this should be done in the context of other nutritional indicators and when values have been reliably measured in a large group of individuals.

A method comparison study between two hemoglobinometer models (Hemocue Hb 301 and Hb 201+) to measure hemoglobin concentrations and estimate anemia prevalence among women in Preah Vihear, Cambodia.

INTRODUCTION: Hemoglobin (Hb) concentration is often measured in global health and nutrition surveys to determine anemia prevalence using a portable hemoglobinometer such as the Hemocue® Hb 201+. More recently, a newer model was released (Hemocue Hb 301) utilizing slightly different methods to measure Hb as compared to the older model. The objective was to measure bias and concordance between Hb concentrations using the Hemocue Hb 301 and Hb 201+ models in a rural field setting. METHODS: Hemoglobin (Hb) concentration was measured using one finger prick of blood (approximately 10 µL) from 175 Cambodian women (18-49 years) using three Hemocue Hb 201+ and three Hb 301 machines. Bias and concordance were measured and plotted. RESULTS: Overall, mean ± SD Hb concentration was 116 ± 13 g/L using the Hb 201+ and 118 ± 12 g/L using the Hb 301; and anemia prevalence (Hb < 120 g/L) was 58% (n = 102) and 58% (n = 101), respectively. Overall bias ± SD was 2.0 ± 10.5 g/L and concordance (95% CI) was 0.63 (0.54, 0.72). Despite the 2 g/L bias detected between models, anemia prevalence was very similar in both models. CONCLUSIONS: The two models measured anemia prevalence comparably in this population of women in rural Cambodia.

The effect of inflammation on serum zinc concentrations and the prevalence estimates of population-level zinc status among Congolese children aged 6-59 months.

BACKGROUND/OBJECTIVES: Zinc is a negative acute-phase reactant; hence, its concentration decreases in the presence of inflammation. There is no current consensus on how to control for the effect of inflammation on serum zinc, which has implications for accurate estimates of population-level zinc status. We aimed to measure the association between inflammation and serum zinc concentrations and to compare the means and the prevalence of zinc deficiency using unadjusted and inflammation-adjusted serum zinc concentrations among Congolese children. SUBJECTS/METHODS: Non-fasting blood was collected in the afternoon in trace element-free vacutainers from 744 apparently healthy children aged 6-59 months in the Democratic Republic of the Congo. Serum was analyzed for zinc, C-reactive protein (CRP) and α-1 acid glycoprotein (AGP) for 665 children with complete data for all three biomarkers. Linear regression was used to generate correction factors (CFs) based on three stages of inflammation: incubation (CRP >5 mg/l and normal AGP), early convalescence (CRP >5 mg/l and AGP >1 g/l) and late convalescence (AGP >1 g/l and normal CRP), relative to no inflammation. RESULTS: Overall unadjusted mean±s.d. serum zinc concentration was 9.4±2.1 µmol/l. Study-generated CFs (95% confidence interval) for incubation, early and late convalescence were 1.01 (0.88, 1.14), 1.15 (1.11, 1.21) and 1.07 (1.03, 1.11), respectively. After applying the CFs, overall adjusted mean±s.d. serum zinc concentration was 10.1±2.2 µmol/l, and prevalence of zinc deficiency (<8.7 µmol/l) decreased from 35% (n=234/665) to 24% (n=160/665). CONCLUSIONS: Adjustment of zinc concentrations for inflammation is warranted when assessing population-level zinc status.European Journal of Clinical Nutrition advance online publication, 23 August 2017; doi:10.1038/ejcn.2017.127.

A comparison of the effects of A1 and A2 beta-casein protein variants on blood cholesterol concentrations in New Zealand adults.

Beta-casein is a cow's milk protein that occurs predominantly in two forms, A1 and A2. Epidemiological evidence suggests that per capita consumption of beta-casein A1 is associated with national mortality rates from ischaemic heart disease. A biological mechanism was proposed after rabbits fed diets containing beta-casein A2 had lower serum cholesterol concentrations and less aortic intimal thickening than rabbits fed beta-casein A1. We tested whether beta-casein A1 and A2 variants differentially affect plasma cholesterol concentrations in humans. In a randomised crossover trial of two four-and-a-half week periods without washout, 62 participants replaced all dairy products in their diet with 500 mL of low-fat milk and 28 g of full-fat cheese that differed in the proportion of beta-casein A1 and A2 variants. Duplicate blood samples were taken on non-consecutive days at the end of each treatment period from 55 people who completed the study. Mean (S.D.) plasma total, low-density and high-density lipoprotein cholesterol concentrations were 5.60 (0.77), 3.73 (0.70) and 1.26 (0.34) mmol/L after the A1 diet and 5.63 (0.81), 3.75 (0.75) and 1.27 (0.37) mmol/L after the A2 diets. We found no evidence that dairy products containing beta-casein A1 or A2 exerted differential effects (P > 0.05) on plasma cholesterol concentrations in humans.

Pathophysiology of apolipoprotein E deficiency in mice: relevance to apo E-related disorders in humans.

Apolipoprotein E (apo E) deficiency (or its abnormalities in humans) is associated with a series of pathological conditions including dyslipidemia, atherosclerosis, Alzheimer's disease, and shorter life span. The purpose of this study was to characterize these conditions in apo E-deficient C57BL/6J mice and relate them to human disorders. Deletion of apo E gene in mice is associated with changes in lipoprotein metabolism [plasma total cholesterol (TC) (>+400%), HDL cholesterol (-80%), HDL/TC, and HDL/LDL ratios (-93% and -96%, respectively), esterification rate in apo B-depleted plasma (+100%), plasma triglyceride (+200%), hepatic HMG-CoA reductase activity (-50%), hepatic cholesterol content (+30%)], decreased plasma homocyst(e)ine and glucose levels, and severe atherosclerosis and cutaneous xanthomatosis. Hepatic and lipoprotein lipase activities, hepatic LDL receptor function, and organ antioxidant capacity remain unchanged. Several histological/immunohistological stainings failed to detect potential markers for neurodegenerative disease in the brain of 37-wk-old male apo E-KO mice. Apo E-KO mice may have normal growth and development, but advanced atherosclerosis and xanthomatosis may indirectly reduce their life span. Apo E plays a crucial role in regulation of lipid metabolism and atherogenesis without affecting lipase activities, endogenous antioxidant capacity, or appearance of neurodegenerative markers in 37-wk-old male mice.

Serum vitamin B12 concentrations and atrophic gastritis in older New Zealanders.

OBJECTIVE: To determine the serum vitamin B(12) status of older New Zealanders and to assess the impact of atrophic gastritis on vitamin B(12) status. DESIGN: A cross-sectional nationally representative population-based survey. METHOD: Serum vitamin B(12) concentrations were used to assess vitamin B(12) status. The presence and severity of atrophic gastritis was classified using serum pepsinogen I and II. SUBJECTS: A total of 466 noninstitutionalized urban and rural dwelling New Zealanders aged 65 y or older who participated in the 1997 National Nutrition Survey. RESULTS: The prevalence of deficient (<148 pmol/l) and marginal (148-221 pmol/l) serum vitamin B(12) concentrations was 12 and 28%, respectively. The prevalence of atrophic gastritis was 6.7% (severe 3.1%, mild-moderate 3.6%). While atrophic gastritis increased the relative risk (RR, 95% CI) of having a deficient or marginal serum vitamin B(12) concentration by 21-fold (6-67) and five-fold (1-17), respectively, those who had atrophic gastritis made up only 33 and 6% of the participants with deficient or marginal serum vitamin B(12) concentrations. An intake of vitamin B(12) from food that exceeded the recommended dietary allowance (2.4 mug/day) did not protect against deficient (RR 0.5; 95% CI: 0.2, 1.2) or marginal (RR 0.9; 95% CI: 0.5, 1.7) serum vitamin B(12) status. Vitamin B(12) supplement users had a reduced risk of having deficient and marginal vitamin B(12) status (RR 0.3; 95% CI: 0.1, 0.8). CONCLUSIONS: There is a relatively high prevalence of deficient and marginal serum vitamin B(12) concentrations among older New Zealanders. However, the prevalence of atrophic gastritis was low in the New Zealand elderly compared with other surveys. Although atrophic gastritis was a risk factor for low vitamin B(12) status, it did not fully explain the prevalence of low serum vitamin B(12).

Household food insecurity and dietary diversity as correlates of maternal and child undernutrition in rural Cambodia.

OBJECTIVES: To assess household food insecurity and dietary diversity as correlates of maternal and child anthropometric status and anemia in rural Cambodia. METHODS: Trained interviewers administered a survey to 900 households in four rural districts of Prey Veng, Cambodia. The Household Food Insecurity Access Scale (HFIAS) and Household Dietary Diversity Score (HDDS) were used to assess household food insecurity and dietary diversity. The height, weight and hemoglobin concentration of the mother and youngest child under 5 years in each household were measured. Multivariate logistic regression models were constructed to assess the association between household food insecurity and dietary diversity, and child stunting and wasting, maternal thinness, maternal and child anemia. RESULTS: The mean (s.d.) HFIAS and HDDS scores were 5.3 (3.9) and 4.7 (1.6), respectively. The respective prevalences of mild, moderate and severe food insecurity were 33, 37 and 12%. Maternal thinness, child stunting and child wasting were present in 14.6, 25.4 and 8.1% of respondents, respectively. The risk of maternal thinness, but not child stunting or wasting, increased as the severity of household food insecurity increased. Household food insecurity was also positively associated with maternal, but not child, anemia. Household dietary diversity status was not significantly associated with any of the outcomes we assessed. CONCLUSIONS: Efforts to improve household food security are important as a means of promoting maternal nutritional status; however, additional research is needed to better understand the role of other factors that are driving the burden of child undernutrition in Cambodia.

Association between dietary fiber intake and the folate status of a group of female adolescents.

The main objective of this study was to assess the association between dietary fiber intake and the folate status of Canadian female adolescents. We also assessed dietary folate intakes and evaluated the prevalence of biochemical folate deficiency in these subjects. Female adolescents aged 14-19 y (n = 224) were recruited and fasting blood samples were collected. Dietary intakes (3-d food record) were recorded and participants were classified as lactoovovegetarians, semivegetarians, or omnivores on the basis of food-consumption patterns assessed with food-frequency questionnaires. Fourteen percent, 17%, and 26% of lactoovovegetarians, semivegetarians, and omnivores, respectively, had dietary folate intakes below their predicted requirements; 1%, 4%, and 23%, respectively, had serum folate concentrations indicative of deficiency. Despite low dietary folate intakes and serum folate concentrations, few subjects had homocysteine concentrations indicative of deficiency, suggesting that the degree of folate depletion had not yet produced functional consequences. Most important, results suggest that the consumption of nonstarch polysaccharide is significantly associated with serum folate concentrations (P < 0.001). For each 1-g increase in nonstarch polysaccharide intake, a 1.8% increase in serum folate concentration is expected. In summary, we propose that an increase in nonstarch polysaccharide intake may promote the intestinal biosynthesis of folate, providing a complementary strategy to enhance the folate nutriture of humans.

A comparison of knobby (K+) and knobless (K-) parasites from two strains of Plasmodium falciparum.

Erythrocytes infected with Plasmodium falciparum develop knob-like protrusions on their membranes. Knobby (K+) parasites of the FCR-3 (Gambian) strain have been shown to possess a histidine-labelled protein of apparent molecular weight 80 000 which is absent from knobless (K-) variants of the same strain. Here we report similar findings with K+ and K- parasites of another strain, the Malayan Camp strain, and also with cloned K+ and K- parasites of the FCR-3 strain. A histidine-labelled protein unique to the two K+ parasites was identified as a broad band with an apparent molecular weight of 89 000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The presence of this protein in both K+ Malayan Camp parasites and K+ FCR-3 (Gambian) parasites and its absence from K- parasites of both strains is consistent with this protein being a major component of knobs.

Cloning and characterization of Plasmodium falciparum FCR-3/FMG strain.

The FCR-3/FMG African strain of Plasmodium falciparum was cloned by the limiting dilution technique in in vitro culture to obtain parasite populations derived from a single cell. The basic in vitro culture technique used was that of Trager and Jensen, performed in microtiter culture plates. The cloning sequence was repeated serially three times, and three parasite clones with a higher than 99% probability of single cell derivation were isolated. Two of these clones were determined by electron microscopic examination to possess the K+ and one the K- trait. The clones were found to be equally sensitive to chloroquine in vitro but varied in their in vivo pathogenicity for Aotus, the K- clone being non-pathogenic.

Capture of attention in selective frequency listening.

Four signal-detection experiments demonstrated robust stimulus-driven, or exogenous, attentional processes in selective frequency listening. Detection of just-above-threshold signal tones was consistently better when the, signal matched the frequency of an uninformative cue tone, even with relatively long cue-signal delays (Experiment 1) or when as few as 1 in 8 signals were at the cued frequency (Experiment 2). Experiments 3 and 4 compared performance with informative and uninformative cues. The involvement of intentional, or endogenous, processes was found to only slightly increase the size of the cuing effect beyond that evident with solely exogenous processes, although the attention band, a measure of how narrowly attention is focused, was found to be wider when cues were informative. The implications for models of auditory attention are discussed.

Inhibition of B16 melanoma metastasis by overexpression of the cysteine proteinase inhibitor cystatin C.

Progression to metastasis has been correlated with increased cysteine proteinase activity for a number of tumour types. One mechanism of cysteine proteinase regulation in normal cells is by natural protease inhibitors, the cystatins. Here we further characterize a transfected cell line showing increased cystatin C transcription driven by cytomegalovirus (CMV) promoter/enhancer sequences. Properties of this cystatin C altered cell line such as growth in vitro, lung colonization after tail vein injection in mice, production of cystatin, and cysteine proteinase inhibitor activities were examined. Although there was no difference between the growth rate of the cystatin transfected cell line and that of the control, there was a substantial difference in metastatic ability. No increase was noted in cystatin C secretion into the media for the cystatin C transfected cell line compared with the control transfected cell line. There was, however, a difference in cysteine protease inhibitor activity in the cell-free extracts. These results show that alteration of cystatin C levels by overexpression in B16 melanoma alters properties associated with metastasis.

Oral contraceptives did not affect biochemical folate indexes and homocysteine concentrations in adolescent females.

OBJECTIVE: The study was designed to determine the impact of currently available oral contraceptive agents (OCAs), smoking, and alcohol on biochemical indexes of folate and vitamin B-12 in adolescent females. DESIGN: Subjects completed a 3-day weighed food record along with a detailed lifestyle questionnaire that included questions on OCA, cigarette, and alcohol use. After subjects had fasted overnight, blood samples were collected and analyzed for levels of serum and red blood cell (RBC) folate and serum B-12 and homocysteine. SUBJECTS/SETTINGS: Two hundred twenty-nine adolescent females (aged 14 to 20 years) were recruited from southern Ontario, Canada, by advertisements in newspapers, high schools, universities, shopping malls, adolescent drop-in centers, and community groups. STATISTICAL ANALYSES PERFORMED: Multiple regression models were used to determine the effect of lifestyle factors and covariates (e.g., dietary folate intake, supplemental folate intake, and age) on biochemical indexes. RESULTS: OCA use, alcohol use, and smoking were not significantly associated with lower serum or RBC folate levels, after controlling for folate intake. Serum homocysteine levels were not associated with smoking or OCA use; however, we estimated a 13% higher concentration among alcohol users than nonusers. Smoking and alcohol use were not associated with serum B-12 levels, but OCA use was associated with an estimated 33% lower serum B-12 level than nonuse. APPLICATIONS: Our findings provide no evidence to suggest that currently available OCAs have a negative impact on the folate status of adolescent females; thus, dietary advice designed to specifically encourage an increase in folate intake among adolescents who use OCAs is not supported. In contrast, serum B-12 levels were lower among OCA users than nonusers, which suggests that an interaction between OCA and some vitamins may persist. The suboptimal biochemical folate indexes of smokers may have more to do with the dietary quality of smokers than previously appreciated. Thus, efforts to improve dietary folate intakes of adolescents who smoke may be an important strategy for improving the folate status of young women.

PIP: The impact of oral contraceptive (OC) use, smoking, and alcohol drinking on biochemical indexes of folate and vitamin B-12 was investigated in 229 adolescents 14-20 years old recruited from advertisements in Ontario, Canada. Subjects completed a life-style questionnaire and a 3-day, weighed food record, followed by overnight fasting and the collection of blood samples. Of the 48 participants (21%) who were OC users, 30 had used the pill for more than 12 months. Only 37 adolescents (16%) smoked, but 94 (60%) had consumed alcohol in the month preceding the study. Median daily intake of folate and vitamin B-12 (including intake from supplements) was 215 mcg and 1.9 mcg, respectively. OC use, smoking, and alcohol consumption were not significantly associated with lower serum or red blood cell folate levels, after controlling for folate intake. Serum homocysteine levels were not correlated with smoking or OC use, but were 13% higher among alcohol drinkers than nondrinkers. Finally, although smoking and alcohol use were not associated with serum B-12 levels, OC use was linked with an estimated 33% lower serum B-12 level than was nonuse. These findings fail to validate concerns that OC use has a negative impact on the folate status of adolescent females, but suggest a need to improve the dietary folate intake of young women who smoke.

Effects of once-a-week or daily folic acid supplementation on red blood cell folate concentrations in women.

OBJECTIVE: Our aim was to determine if a once-a-week folic acid supplement increases women's red blood cell folate to concentrations (>905 nmol/l) that are associated with a low risk of bearing a child with a neural tube defect. DESIGN: Randomized control trial. SETTING: General community. SUBJECTS: In total, 114 nonpregnant women (18-40 y) volunteers, with red blood cell folate concentrations between 295 and 905 nmol/l at screening. INTERVENTION: Women were randomized to receive a once-a-week 2800 microg folic acid supplement, a daily 400 microg folic acid supplement or a daily placebo for 12 weeks. RESULTS: The mean (95% CI) red blood cell folate concentrations increased during the 12-week intervention from 608 (553-668) to 900 (828-978) in the weekly folic acid group (P<0.05) and from 615 (560-677) to 1053 (957-1158) nmol/l in the daily group (P<0.05) during the trial. At week 12, 49% of women ingesting the weekly folic acid supplement had red blood cell folate concentrations greater than 905 nmol/l compared to 74% of women ingesting the daily supplement. CONCLUSION: A once-a-week 2800 microg folic acid supplement can increase women's red blood cell folate to concentrations associated with a reduced risk of bearing a child with a neural tube defect, but is less effective than a 400 microg daily supplement. Use of a weekly folic acid supplement over at least 12 weeks before conception by women of child-bearing age may prevent neural tube defects. FUNDING: The Otago Medical Research Foundation (Laurenson Award). Healtheries (New Zealand) provided the supplements.

Bacterial mutagenicity studies on chloroform in vitro.

Chloroform was tested for mutagenicity in the Salmonella/microsome assay using five strains of Salmonella typhimurium. In view of previous reports describing the development of liver and kidney tumours in some experiments involving long-term administration of chloroform to rats and mice, the mutagenicity tests were carried out in the absence of any S-9 microsomal-enzyme preparation and in the presence of S-9 microsomal-enzyme preparations derived from (a) livers and (b) kidneys of rats and mice previously exposed to the microsomal-enzyme inducer Aroclor 1254. No evidence of potential mutagenicity was observed under any of the test conditions. To determine whether the findings might have been influenced by the volatility of the chloroform, the test organisms were exposed to chloroform vapour, but again chloroform gave no indication of potential mutagenicity. Taken in conjunction with already published data from mutagenicity studies with chloroform, it appears unlikely that the tumours observed in some long-term rodent studies are attributable to a genotoxic action of the compound.

Patients' diets and preferences in a pediatric population with inflammatory bowel disease.

PURPOSE: To determine the dietary practices of the pediatric inflammatory bowel disease population at the Children's Hospital of the Hamilton Health Sciences Corporation and the reported effectiveness of those diets. PATIENTS AND METHODS: A questionnaire mailed to 153 pediatric patients was returned by 125 patients (76 Crohn's disease [CD] and 49 ulcerative colitis [UC] patients)--an 82% response rate. RESULTS: The median age of respondents was 13 years, and 62% were male. Ninety per cent and 71% of CD and UC patients, respectively, had changed their diets since diagnosis. Caloric supplements (eg, BOOST [Mead Johnson Nutritionals]), sole source nutrition, low fibre and lactose-free diets were used by more than 15% of CD patients, whereas lactose-free, nonspicy, low acid, additive-free, caloric supplement and low fibre diets were used by more than 15% of UC patients. A diet supplement was more commonly used in CD patients (P < 0.05) and an additive-free diet in UC patients. Corn and corn products, nuts, milk and bran were avoided by more than 20% of CD and UC patients; however, more CD than UC patients avoided corn and corn products. In addition, UC patients (more than 20%) also avoided tomato, other dairy (nonfluid milk-based products and foods containing milk products), chocolate, cheese, wheat, tomato sauces and fruit juice. A benefit was reported for 103 of 141 reported diets, with the most commonly alleviated symptoms being abdominal pain, diarrhea and flatulence. CONCLUSION: Many children with inflammatory bowel disease have altered their diets to manage their disease and have attributed symptomatic relief to these diets.