Microbiological assay for vitamin B12 with use of a colistin-sulfate-resistant organism.

Kelleher, Brian P.; Walshe, Kieran; Scott, John M.; O’Broin, S.

doi:10.1093/clinchem/33.1.52

Cited by 63 publications

(35 citation statements)

References 9 publications

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“…Plasma was separated and stored at -80°C prior to analysis. Plasma concentrations of folate and vitamin B12 were determined by microbiological assay (Kelleher et al 1987;Horne & Patterson 1988) at the Diabetes Unit, KEM Hospital Research Centre, Pune, India. Intra-and inter-assay coefficients of variation (CV) were <8% for both assays.…”

Section: Measurement Of Blood Nutrient Concentrationsmentioning

confidence: 99%

Diet patterns are associated with demographic factors and nutritional status in South Indian children

Kehoe

Krishnaveni

Veena

et al. 2013

Maternal & Child Nutrition

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The burden of non-communicable chronic disease (NCD) in India is increasing. Diet and body composition ‘track’ from childhood into adult life and contribute to the development of risk factors for NCD. Little is known about the diet patterns of Indian children. We aimed to identify diet patterns and study associations with body composition and socio-demographic factors in the Mysore Parthenon Study cohort. We collected anthropometric and demographic data from children aged 9.5 years (n = 538). We also administered a food frequency questionnaire and measured fasting blood concentrations of folate and vitamin B12. Using principal component analysis, we identified two diet patterns. The ‘snack and fruit’ pattern was characterised by frequent intakes of snacks, fruit, sweetened drinks, rice and meat dishes and leavened breads. The ‘lacto-vegetarian’ pattern was characterised by frequent intakes of finger millet, vegetarian rice dishes, yoghurt, vegetable dishes and infrequent meat consumption. Adherence to the ‘snack and fruit’ pattern was associated with season, being Muslim and urban dwelling. Adherence to the lacto-vegetarian pattern was associated with being Hindu, rural dwelling and a lower maternal body mass index. The ‘snack and fruit’ pattern was negatively associated with the child's adiposity. The lacto-vegetarian pattern was positively associated with blood folate concentration and negatively with vitamin B12 concentration. This study provides new information on correlates of diet patterns in Indian children and how diet relates to nutritional status. Follow-up of these children will be important to determine the role of these differences in diet in the development of risk factors for NCD including body composition.

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Section: Measurement Of Blood Nutrient Concentrationsmentioning

confidence: 99%

Diet patterns are associated with demographic factors and nutritional status in South Indian children

Kehoe

Krishnaveni

Veena

et al. 2013

Maternal & Child Nutrition

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“…tHcy and MMA were analysed using a modification of a gas chromatography method based on ethylchloroformate derivatization [23]. Plasma folate [24] and cobalamin [25] were analysed by published methods. Results on vitamin B6 (pyridoxal phosphate, PLP) have previously been presented [26].…”

Section: Blood Collection and Biochemical Analysesmentioning

confidence: 99%

Homocysteine‐lowering therapy does not affect inflammatory markers of atherosclerosis in patients with stable coronary artery disease

Bleie

Semb

Grundt

et al. 2007

Journal of Internal Medicine

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. Objectives. A high level of total homocysteine (tHcy) is a risk marker for cardiovascular disease (CVD), and is related to inflammation. We wanted to test the effect of homocysteine‐lowering B‐vitamin therapy, as used in the Western Norway B‐vitamin Intervention Trial (WENBIT), on inflammatory markers associated with atherosclerosis. Design. Single centre, prospective double‐blind clinical interventional study, randomised in a 2 × 2 factorial design. Subjects and methods. Ninety patients (21 female) with suspected coronary artery disease (CAD), aged 38–80 years, were blindly randomised into one of four groups of daily oral treatment with (A) folic acid (0.8 mg)/vitamin B12 (0.4 mg)/vitamin B6 (40 mg), (B) folic acid/vitamin B12, (C) vitamin B6 alone or (D) placebo. Blood samples were collected before and after 6 months of treatment. Results. Before intervention, median levels of the analytes were: tHcy 11.0 μmol L−1, neopterin 8.1 nmol L−1, soluble CD40 ligand (sCD40L) 3.9 ng mL−1, interleukin (IL)‐6 1.9 pg mL−1, C‐reactive protein (CRP) 1.9 mg L−1 and low‐density lipoprotein (LDL) cholesterol 3.3 mmol L−1. tHcy was significantly associated with neopterin (r = 0.49, P < 0.001) and with IL‐6 (r = 0.29, P = 0.01), but not with CRP or sCD40L. Neither treatment with folic acid/B12 nor with B6 induced significant changes in any of these inflammatory biomarkers (P ≥ 0.14). In patients receiving folic acid/B12 (groups A and B), tHcy was reduced with 33% (P < 0.001). Conclusions. In patients with stable CAD, homocysteine‐lowering therapy with B‐vitamins does not affect levels of inflammatory markers associated with atherogenesis. Failure to reverse inflammatory processes, may partly explain the negative results in clinical secondary B‐vitamin intervention trials.

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“…Vitamin B,, assay medium USP was obtained from Difco Laboratories, Detroit, MI, was developed in this laboratory (Kelleher et al 1987)…”

Section: Materials and Methods M A T E R I A L Smentioning

confidence: 99%

“…There is as yet no reported method of eliminating antibiotic interference in microbiological assays and the use of a commercial radioassay remains the only option with certain samples. The development of a colistin sulphate-resistant strain of L. leichmannii (NCIB 12519) greatly simplified the vitamin B,, microbiological assay (Kelleher et al 1987). The modified technique eliminated an autoclaving step in procedure, allowed bulk inoculation of the medium, and improved overall assay accuracy and precision.…”

Section: Introductionmentioning

confidence: 99%

Use of beta-lactamase to hydrolyse interfering antibiotics in vitamin B12 microbiological assay using Lactobacillus leichmannii

Kelleher

Scott

O’Broin

2008

Clinical &Amp; Laboratory Haematology

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Summary The presence of certain antibiotics in patients' sera can invalidate microbiological assays for vitamin B12 using Lactobacillus leichmannii by inhibiting organism growth. Analysis of 3291 consecutive serum vitamin B12assays in a large general hospital service showed inhibition of growth in 303 samples (9.2%). In nearly all cases the interfering substance was a beta‐lactam antibiotic. The value of using a beta‐lactamase preparation to eliminate antibiotic effects was studied using antibiotic‐containing patient sera and also normal serum to which antibiotics were added. In‐vitro additions of penicillins, cephalosporins, and other antibiotics to normal serum resulted in varying levels of organism inhibition, but excellent recovery of a control value after treatment with beta– lactamase (> 98%). Patient sera showing inhibition were reassayed in duplicate following treatment with beta‐lactamase (n= 200), the overall effectiveness of the treatment being verified by the excellent recovery (> 98%) of a cyanocobalamin ‘spike’ added to a control. In only 0.2% of cases (6 of 3291 samples) was this treatment ineffective and it has thus proved an efficient method of eliminating the problem of antibiotic interference in the vitamin B12microbiological assay.

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Microbiological assay for vitamin B12 with use of a colistin-sulfate-resistant organism.

Cited by 63 publications

References 9 publications

Diet patterns are associated with demographic factors and nutritional status in South Indian children

Diet patterns are associated with demographic factors and nutritional status in South Indian children

Homocysteine‐lowering therapy does not affect inflammatory markers of atherosclerosis in patients with stable coronary artery disease

Use of beta-lactamase to hydrolyse interfering antibiotics in vitamin B12 microbiological assay using Lactobacillus leichmannii

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