Vitamin B complex and vitamin B12 levels after peripheral nerve injury

The aim of the present study was to evaluate whether tissue levels of vitamin B complex and vitamin B12 were altered after crush-induced peripheral nerve injury in an experimental rat model. A total of 80 male Wistar rats were randomized into one control（n = 8） and six study groups（1, 6, 12, 24 hours, 3, and 7 days after experimental nerve injury; n = 12 for each group）. Crush-induced peripheral nerve injury was performed on the sciatic nerves of rats in six study groups. Tissue samples from the sites of peripheral nerve injury were obtained at 1, 6, 12, 24 hours, 3 and 7 days after experimental nerve injury. Enzyme-linked immunosorbent assay results showed that tissue levels of vitamin B complex and vitamin B12 in the injured sciatic nerve were significantly greater at 1 and 12 hours after experimental nerve injury, while they were significantly lower at 7 days than in control group. Tissue level of vitamin B_（12） in the injured sciatic nerve was significantly lower at 1, 6, 12 and 24 hours than in the control group. These results suggest that tissue levels of vitamin B complex and vitamin B12 vary with progression of crush-induced peripheral nerve injury, and supplementation of these vitamins in the acute period may be beneficial for acceleration of nerve regeneration.

SIMULTANEOUS DETERMINATION OF VITAMIN B COMPLEX (THIAMINE, RIBOFLAVIN, NIACIN, PYRIDOXINE AND FOLIC ACID) IN FOODS BY HPLC

A high performance liquid chromatographic assay has been developed for the simultaneous determination of five water soluble vitamins:thimine, riboflavin, niacin, pyridoxine and folic acid in cereal products and fresh vegetables. Food samples were hydrolyzed in 0.4 mol/L HCl, autoclaved at 120℃ 15 psi for 20 minutes, using a μ-Bondapak column (3.9×300mm, Waters Co.), a mobile phase of methanol-water (30:70) (0.005 mol/L heptanesulfonic acid) and a flow rate of 1.0 ml/min gave the most satisfactory separation of the five water soluble vitamins. A double channel deteetion was used: four vitamins (B_5, folic acid, B_2, B_1) were detected hy UV spectrophotometry (254 nm) first, pyridoxine (B_6) was detected by fluoromelry (EX 290nm, EM 395 nm) afterwards. Detection limits were 2, 5, 5, 2and 5ng, linear ranges were 5-10ng, 5-50ng, 5-40ng, 5-50ng and 10-50ng for B_1, B_2, B_5, B_6 and folic acid respectively. Recoveries were 92-100%(B_5), 51-52% (folio acid), 103—105% (B_2), 99—100% (B_6) and 91.3—102% (B_1) respectively. In comparison with a reference method and checking with food composition tables, very satisfactory results were obtained by this method.

Association of Serum Folate and Vitamin B_(12) Concentrations with Obesity in Chinese Children and Adolescents

Objective This study aimed to evaluate the associations of serum folate and/or vitamin B12 concentrations with obesity among Chinese children and adolescents.Methods A cross-sectional study was conducted including 3,079 Chinese children and adolescents,aged 6 to 17 years,from Jiangsu,China.Anthropometric indices,such as,children's body mass index(BMI),BMI z-scores,waist circumference,and waist-to-height ratio were utilized.Multivariable linear regression and generalized additive models were used to investigate the associations of serum folate and vitamin B12 levels with anthropometric indices and odds of obesity.Results We observed that serum vitamin B12 concentrations were inversely associated with all anthropometric indices and the odds of general obesity[odds ratio(OR)=0.68;95%confidence interval(CI)=0.59,0.78]and abdominal obesity(OR=0.68;95%CI=0.60,0.77).When compared to participants with both serum vitamin levels in the two middle quartiles,those with both serum folate and vitamin B12 levels in the highest quartile were less prone to general(OR=0.31,95%CI=0.19,0.50)or abdominal obesity(OR=0.46,95%CI=0.31,0.67).Conversely,participants with vitamin B12 levels in the lowest quartile alongside folate levels in the highest quartile had higher odds of abdominal obesity(OR=2.06,95%CI=1.09,3.91).Conclusion Higher serum vitamin B12 concentrations,but not serum folate concentrations,were associated with lower odds of childhood obesity.Children and adolescents with high levels of vitamin B12 and folate were less likely to be obese.

Neurological Manifestations of Vitamin B12 Deficiency: About a Case

The authors report a case of deficient sensory neuropathy secondary to vitamin B12 deficiency, diagnosed in the neurology department of the Sino-Central African Friendship University Hospital in Bangui. The diagnosis was made possible by electroneuromyography which showed subclinical neurological damage associated with hematological damage (anemia). Through this observation, we recall the diagnostic criteria of the disease in a context of difficult medical practice. .

Association between metformin and vitamin B12 deficiency in patients with type 2 diabetes

Diabetes mellitus(DM)is still one of the most common diseases worldwide,and its prevalence is still increasing globally.According to the American and European recommendations,metformin is considered a first-line oral hypoglycemic drug for controlling type 2 DM(T2DM)patients.Metformin is the ninth most often prescribed drug in the world,and at least 120 million diabetic people are estimated to receive the drug.In the last 20 years,there has been increasing evidence of vitamin B12 deficiency among metformin-treated diabetic patients.Many studies have reported that vitamin B12 deficiency is related to the malabsorption of vitamin B12 among metformin-treated T2DM patients.Vitamin B12 deficiency may have a very bad complication for the T2DM patient.In this review,we will focus on the effect of metformin on the absorption of vitamin B12 and on its proposed mechanisms in hindering vitamin B12 absorption.In addition,the review will describe the clinical outcomes of vitamin B12 deficiency in metformintreated T2DM.

Vitamin B3 inhibits apoptosis and promotes autophagy of isletβcells under high glucose stress

Background:Hyperglycemia is a typical symptom of diabetes.High glucose induces apoptosis of isletβcells.While autophagy functions in cytoprotection and autophagic cell death.The interaction between autophagy and apoptosis is important in the modulation of the function of isletβcells.Vitamin B3 can induce autophagy and inhibit isletβapoptosis.Method:The mechanism of vitamin B3-mediated protective effect on the function of isletβcells was explored by the method of western blot,immunofluorescence and flow cytometry.Results:In the present study,high glucose stress increased the apoptosis rate,while vitamin B3 reduced the apoptosis rate.The effect of vitamin B3 on autophagy flux under normal and high glucose stress was also investigated.Vitamin B3 increased the number of autophagosomes and increased the light chain(LC)3-II/LC3-I ratio.In contrast,vitamin B3 decreased sequestosome 1(SQSTM1)/p62 protein expression and inhibited the phosphorylation of mammalian ribosomal protein S6 kinaseβ-1(p70S6K/S6K1),which was a substrate of mammalian target of rapamycin(mTOR)under normal and high glucose stress.To further verify the protective effect of vitamin B3 on apoptosis,we treated isletβcell RIN-m5F with autophagy inhibitor 3-methyladenine(3-MA).Vitamin B3 decreased the apoptosis rate under high glucose stress,while the inhibition of apoptosis by vitamin B3 was blocked after adding 3-MA.Conclusion:Our data suggested that vitamin B3 reduced the apoptosis rate ofβcells,possibly through inducing autophagy under high glucose stress.

Decreased Expression of Vitamin K Epoxide Reductase Complex Subunit 1 in Kidney of Patients with Calcium Oxalate Urolithiasis

Urinary prothrombin fragment 1 （UPTFl） is a potent inhibitor of urinary stone formation. UPTF1 exerts such inhibitory effect by effective 7-carboxylation in which vitamin K epoxide reductase complex subunit 1 （VKORC1）, the rate-limiting enzyme, is involved. This study examined the correlation between VKORC1 expression and calcium oxalate urolithiasis. The renal cortex samples were obtained from patients undergoing nephrectomy and then divided into 3 groups： urolithiasis group, control group A [hydronephrosis-without-stone （HWS） group], control group B （normal control group）, The localization and expression of VKORC1 in renal tissues were determined by using immunohistochemistry, immunofluorescence microscopy, Western blotting and SYBR Green I real-time reverse-transcription PCR. The rapid amplification of cDNA ends （RACE） were conducted to obtain the 3＇- and 5＇-untranslated region （UTR） of VKORC1. The results showed that VKORC1 was located in the cytoplasm of renal tubular epithelial cells. The expression of VKORC1 in the uro- lithiasis group was significantly lower than that in the other two control groups （P〈0.05）. Moreover, the 3＇- and 5＇-UTR sequence of the VKORC1 gene was successfully cloned. No insertion or deletion was found in the 3＇- and 5＇-UTR. However, a 171-bp new base sequence was discovered in the up- stream of 5＇-UTR end in the urolithiasis group. It was concluded that the decreased expression of VKORC 1 may contribute to the development of calcium oxalate urolithiasis in the kidney.

Iron versus Iron and Vitamin B6 Supplementation in Treatment of Iron Deficiency Anemia during Second Trimester of Pregnancy: Quasi Experimental Trial

Background: Anemia is one of the most prevalent complications during pregnancy. It is commonly considered a risk factor for poor pregnancy outcomes and can result in complications that threaten the life of both mother and fetus, such as preterm birth, and low birth weight. There is clear evidence to support prompt treatment in all patients with iron deficiency anemia because it is known that treatment improves quality of life and physical condition as well as alleviates fatigue and cognitive deficits. Objective: The aim of the study was to evaluate the value of addition of vitamin B6 to iron in treatment of iron deficiency anemia in pregnant women during the second trimester. Patients and Methods: The study was done by giving anemia pregnant women iron therapy and vitamin B6 which represent group A and iron therapy alone which represents group B. For each pregnant woman, age, parity and gestational history were taken before treatment. All pregnant women took their allocated treatment regularly for three weeks after diagnosis of iron deficiency anemia with complete blood picture and followed up after three weeks. Results: Results of the study revealed that there was no statistically significant difference between the two groups of therapy according to the hemoglobin level before treatment (p-value = 0.734), statistically significant higher mean value in after treatment than before treatment (p-value = 0.048), there was a significant difference in the rate of change of hemoglobin (p-value = 0.011) and body mass index (p-value 0.001). Conclusion: Iron and vitamin B6 seems to increase hemoglobin level more than iron only. Thus, in pregnant women with iron deficiency anemia iron plus vitamin B6 may be considered as a more effective alternative treatment than iron only.

Studies on the Stability and Structure of β-cyclodextrin Vitamin D_2 Inclusion Complex

The inclusion complex of β\|cyclodextrin (βCD) with Vitamin D 2 (VD 2 ) was prepared in 60% ethanol aqueous solution. The accelerated tests of the inclusion complex βCD\|VD 2 were performed under strong light, high temperature and high humidity. The results showed that the content of VD 2 in the inclusion complex was still kept 85%~95% after two years, while that in the βCD and VD 2 mixture was just 17%~22%. It indicated that VD 2 in inclusion complex was much more stable than pure VD 2. Therefore, adding the inclusion complex βCD\|VD 2 into “Longmu” Zhuanggu Chongji, a medicine for children to prevent and cure rickets, can not only decrease the expense of VD 2, but also enhance the stability of the products. IR, X\|ray, DTA and UV techniques were used to characterize the structures of the inclusion complex. The results indicated that intermolecular hydrogen bonds formed in the βCD\|VD 2 inclusion complex.

Non-SMC condensin Ⅰ complex subunit D2 and non-SMC condensin Ⅱ complex subunit D3 induces inflammation via the IKK/NF-κB pathway in ulcerative colitis

BACKGROUND Ulcerative colitis(UC)is a chronic,nonspecific intestinal inflammatory disease with undefined pathogenesis.Non-SMC condensin I complex subunit D2(NCAPD2)and non-SMC condensin II complex subunit D3(NCAPD3)play pivotal roles in chromosome assembly and segregation during both mitosis and meiosis.To date,there has been no relevant report about the functional role of NCAPD2 and NCAPD3 in UC.AIM To determine the level of NCAPD2/3 in intestinal mucosa and explore the mechanisms of NCAPD2/3 in UC.METHODS Levels of NCAPD2/3 in intestinal tissue were detected in 30 UC patients and 30 healthy individuals with in situ hybridization(ISH).In vitro,NCM60 cells were divided into the NC group,model group,si-NCAPD2 group,si-NCAPD3 group and si-NCAPD2+si-NCAPD3 group.Inflammatory cytokines were measured by ELISA,IKK and NF-κB were evaluated by western blot,and IKK nucleation and NF-κB volume were analyzed by immunofluorescence assay.RESULTS Compared with expression in healthy individuals,NCAPD2 and NCAPD3 expression in intestinal tissue was significantly upregulated(P<0.001)in UC patients.Compared with levels in the model group,IL-1β,IL-6 and TNF-αin the si-NCAPD2,si-NCAPD3 and si-NCAPD2+si-NCAPD3 groups were significantly downregulated(P<0.01).IKK and NF-κB protein expression in the si-NCAPD2,si-NCAPD3 and si-NCAPD2+si-NCAPD3 groups was significantly decreased(P<0.01).Moreover,IKK nucleation and NF-κB volume were suppressed upon si-NCAPD2,si-NCAPD3 and si-NCAPD2+si-NCAPD3 transfection.CONCLUSION NCAPD2/3 is highly expressed in the intestinal mucosa of patients with active UC.Overexpression of NCAPD2/3 promotes the release of pro-inflammatory cytokines by modulating the IKK/NF-κB signaling pathway.

Quantum-chemical Study on the Structures and Properties of Uracil-BX_3 (X = F,Cl) Complexes

For the uracil-BX3 （X = F, Cl） systems, geometries and binding energies have been calculated by using the Lee-Young-Parr correlation functionals （B3LYP） method of density functional theory （DFT） and the second-order Moller-Plesset （MP2） method of ab initio at the 6- 311 ＋G^＊ or 6-311 ＋＋G^＊ basis set. Four isomers were found for each system, and then the single-point energy evaluations were performed using the larger basis sets of （6-311 ＋G（2df, p） and aug-cc-pVDZ with DFF method. In the most stable isomer of uracil-BF3 or uracil-BCl3, the boron atom of BX3 （X = F, Cl） connects to the carbonyl oxygen O7 of uracil with a stabilization energy of -46.56 or -31.10 kJ/mol at the B3LYP/6-31 1＋G^＊ level （BSSE corrected）. The analyses for combining interaction between BX3 and uracil with the atom-in-molecule theory （AIM） and natural bond orbital method （NBO） have been performed. The results indicate that all isomers were formed with σ-p type interactions between uracil and BX3, in which the carbonyl oxygen offers its lone pair electrons to the empty p orbital of boron atom and the concomitances of charge transfer from uracil to BX3 occur. Moreover, there exists one or two hydrogen bonds in most isomers of uracil-BX3 system and these hydrogen bonds contribute to the stability of the complex systems. Frequency analysis suggests that the stretching vibration of BX3 undergoes a red shift in complexes. Uracil-BF3 complex is more stable than uracil-BCl3 although the distance of B-O is shorter in the latter. Besides, the conversion mechanisms between different isomers of uracil-BF3 have been obtained.

Studies on Non-potentiometric Piezoelectric Sensor System for Determination of Vitamin B_1

A piezoelectric sensor responsive to vitamin B 1 was fabricated based on the vitamin B 1 tetraphenylborate ion pair. The general performance characteristics of the sensor are presented here. The proposed sensor showed a wide working pH range, a good sensitivity and selectivity. The response range is between 1 0×10 -7 -4 9×10 -5 mol/L with a detection limit of 8×10 -8 mol/L at pH 4 0. The selectivity should be attributed to the preferential adsorption of the component ion on the membrane/solution interface. The adsorption behavior of vitamin B 1 on the crystal surface was investigated with a quartz crystal impedance(QCI) system.

血管性痴呆患者血清叶酸、Vitamin B_(12)水平变化的临床研究

目的测定血管性痴呆(VD)与非痴呆脑血管病(NDCVD)患者及健康老年者血清叶酸、Vitamin B_(12)水平,同时评估认知功能的变化,分析并探讨其在VD的可能作用。方法选择VD40人,为痴呆组;NDCVD40人,为非痴呆组;同期选定40名健康老年人作为对照组。应用MMSE对3组对象的认知功能进行评定,测定被试着血清叶酸、Vitamin B_(12)水平。初步观察补充叶酸、Vitamin B_(12)对VD认知功能的影响。结果3组血清叶酸、Vitamin B_(12)水平(以中位数M及95%的可信区间CI表示),以VD组最低为4.20ng/ml(4.07～5.50)、343.67pg/ml(296.54～413.73)。与对照组比较有显著性(P<0.01),VD与NDCVD组相比叶酸水平不同(P<0.01),而Vitamin B_(12)水平无差别(P>0.05)。3组MMSE值VD组最低(16.05±5.94),各组之间明显不同(P<0.01)。初步显示补充叶酸、Vita- min B_(12)对VD患者认知功能有一定的改善作用。结论VD患者血清叶酸、Vitamin B_(12)水平明显低于健康者,低水平叶酸、Vitamin B_(12)可能对VD的认知功能有影响。

Role of vitamin B12 deficiency in ischemic stroke risk and outcome

Currently,ischemic stroke is the most prevalent form of stroke compared to hemorrhagic and there is a high incidence in older adults.Nutrition is a modifiable risk factor for stroke.B-vitamins are part of a metabolic network that integrates nutritional signals with biosynthesis,redox homeostasis,and epigenetics.These vitamins play an essential role in the regulation of cell proliferation,stress resistance,and embryo development.A deficiency in vitamin B12 is common in older adults and has been reported to be implicated in ischemic stroke.The aim of this review was to investigate whether vitamin B12 deficiencies impact the risk and outcome of ischemic stroke.Clinical data from our literature review strongly suggest that a deficiency in vitamin B12 is a risk factor for ischemic stroke and possible outcome.Our survey of the literature has identified that there is a gap in the understanding of the mechanisms through which a vitamin B12 deficiency leads to an increased risk of stroke and outcome.A vitamin B12 deficiency can increase homocysteine levels,which are a well-established risk factor for ischemic stroke.Another potential mechanism through which vitamin B12 deficient may impact neurological function and increase risk of stroke,is changes in myelination,however this link requires further investigation.Further studies are required in model systems to understand how a vitamin B12 deficiency changes the brain.

Prostaglandin E_1 in conjunction with high doses of vitamin B_(12) improves nerve conduction velocity of patients with diabetic peripheral neuropathy

BACKGROUND： Prostaglandin El improves diabetic peripheral neuropathy in symptoms and sensory threshold. Vitamin Bi and methyl-vitamin BI2 improve microcirculation to peripheral nerve tissue and promote neurotrophy. OBJECTIVE： To observe motor nerve and sensory nerve conduction velocity in patients with diabetic peripheral neuropathy, prior to and after treatment with prostaglandin El, vitamin B I and different doses of vitamin B 12. DESIGN, TIME AND SETTING： Randomized, controlled experiment, performed at the Department of Neurology, Beijing Hantian Central Hospital, between February 2002 and September 2007. PARTICIPANTS： A total of 122 patients with type 2 diabetic peripheral neuropathy; 73 males and 49 females were included. All patients met the diagnostic criteria of diabetes mellitus, as determined by the World Health Organization in 1999 and 2006, and also the diagnostic criteria of diabetic peripheral neuropathy. For each subject, conduction disorders in the median nerve and in the common peroneal nerve were observed using electromyogram. Also, after diet and drug treatment, the blood glucose level of subjects was observed to be at a satisfactory level for more than two weeks, and the symptoms of diabetic peripheral neuropathy were not alleviated. METHODS： All patients were randomly divided into the following three groups. A control group （n = 40）, in which, 100 mg vitamin B1 and 500 μg vitamin BI2 were intramuscularly injected. A vitamin B12 low-dose treated group （ n = 42）, in which 10 μ g prostaglandin E1 in 250 mL physiological saline was intravenously injected once a day and 100 mg vitamin BI and 500 11 g vitamin BI2 was intramuscularly injected once a day. Lastly, a vitamin B12 high-dose treated group （n = 40）, in which administration was the same as in the vitamin B12 low-dose treated group, except that 500 11 g vitamin BI2 was replaced by 1mg vitamin B12. Administration was performed for four weeks for each group. MAIN OUTCOME MEASURES： The motor nerve and sensory nerve conduction velocity of the median nerve and the common peroneal nerve were determined using an electromyogram electronic stimulator （Neuropack-11, Nihon Kohden, Japan）. RESULTS： The motor nerve and sensory nerve conduction velocities of the median nerve and the common peroneal nerve were significantly faster after treatment compared to before treatment in all 3 groups （P 〈 0.05q）.01）. Compared with the control group, the motor nerve and sensory nerve conduction velocities were significantly faster in the vitamin B12 low-dose treated group and in the vitamin B12 high-dose treated group （P 〈 0.01）. The motor nerve and sensory nerve conduction velocities were significantly faster in the vitamin B12 high-dose treated group compared to the vitamin B12 low-dose treated group （P 〈 0.05）. CONCLUSION： Prostaglandin E1, in conjunction with vitamin B12, can improve neural functional states and speed up peripheral motor nerve and sensory nerve conduction velocity in diabetic peripheral neuropathy. In addition, better effects are achieved using prostaglandin E1 in conjunction with high doses of vitamin B 12.

CdTe quantum dots as fluorescence sensor for the determination of vitamin B6 in aqueous solution

A novel, rapid and simple CdTe quantum dots （QDs） based technology platform was established for selective and sensitive determination of vitamin B6 in aqueous solution. It can perform accurate and reproducible quantification of vitamin B6 in pharmaceutical with satisfactory results.

Use of packed-fiber solid-phase extraction for sample clean-up and preconcentration of vitamin B_(12) before determination

A rapid and simple preconcentration step applying packed-fiber solid-phase extraction columns has been investigated to vitamin B12. The extraction performance of the new method was investigated preliminarily on vitamin functional drink. The analysis used a reversed-phase C18 column, with a photo-diode array detector at 220 nm. The samples were preconcentrated with packed-fiber solid-phase extraction columns. Good linearity was observed in vitamin functional drink. The repeatability of extraction performance, expressed as relative standard deviations, was from 3.5% to 4.3%. The limit of detection （LOD） is 5 ng mL^-1 （S/N = 3）. Finally, the method had been applied for the determination of vitamin B12 in vitamin functional drink.

Long-term metformin therapy and vitamin B12 deficiency: An association to bear in mind

To date,metformin remains the first-line oral glucose-lowering drug used for the treatment of type 2 diabetes thanks to its well-established long-term safety and efficacy profile.Indeed,metformin is the most widely used oral insulinsensitizing agent,being prescribed to more than 100 million people worldwide,including patients with prediabetes,insulin resistance,and polycystic ovary syndrome.However,over the last decades several observational studies and meta-analyses have reported a significant association between long-term metformin therapy and an increased prevalence of vitamin B12 deficiency.Of note,evidence suggests that long-term and high-dose metformin therapy impairs vitamin B12 status.Vitamin B12(also referred to as cobalamin)is a water-soluble vitamin that is mainly obtained from animal-sourced foods.At the cellular level,vitamin B12 acts as a cofactor for enzymes that play a critical role in DNA synthesis and neuroprotection.Thus,vitamin B12 deficiency can lead to a number of clinical consequences that include hematologic abnormalities(e.g.,megaloblastic anemia and formation of hypersegmented neutrophils),progressive axonal demyelination and peripheral neuropathy.Nevertheless,no definite guidelines are currently available for vitamin B12 deficiency screening in patients on metformin therapy,and vitamin B12 deficiency remains frequently unrecognized in such individuals.Therefore,in this“field of vision”article we propose a list of criteria for a cost-effective vitamin B12 deficiency screening in metformin-treated patients,which could serve as a practical guide for identifying individuals at high risk for this condition.Moreover,we discuss additional relevant topics related to this field,including:(1)The lack of consensus about the exact definition of vitamin B12 deficiency;(2)The definition of reliable biomarkers of vitamin B12 status;(3)Causes of vitamin B12 deficiency other than metformin therapy that should be identified promptly in metformin-treated patients for a proper differential diagnosis;and(4)Potential pathophysiological mechanisms underlying metformin-induced vitamin B12 deficiency.Finally,we briefly review basic concepts related to vitamin B12 supplementation for the treatment of vitamin B12 deficiency,particularly when this condition is induced by metformin.

Influence of Different Ratios of Cobalt and Copper Supplementation on Vitamin B_(12) Status and Nutrient Utilization in Sheep

The present study is aimed to investigate the effects of different ratios of cobalt （Co） and copper （Cu） supplementation on vitamin B12 status and nutrient utilization in sheep. Twenty wether lambs with an average weight （22.9 ± 0.8） kg were randomly divided into five groups and fed with the control diet which was supplied with 0.3 mg kg^-1 DM （dry matter） of Co to the basal diet, and four supplemental diets which were supplied either 0.3 or 0.6 mg kg^-1 DM of Co and 10 or 20 mg kg^-1 DM of Cu to the basal diet, respectively for 8 wk. The supplementation of Co and Cu with different levels improved plasma vitamin B12 concentration which was increased with feeding time, but stable after 6 wk. Vitamin B12 status was accounted for Co intake with no combined effects by supplementation of different levels of Co and Cu. The plasma concentrations of methylmalonic acid, homocysteine, folic acid, and glucose did not show the consistent results with plasma vitamin B12, which was considered to be resulted from Cu action. Addition of Co and Cu with different levels had no influence on digestibility of dry matter （DM）, organic matter （OM）, crude protein （CP） and nitrogen free （NFE）, and N metabolism （P〉 0.05）, but the digestibility of fat and fibre （P〈0.01） was enhanced by supplementation of 0.3 mg kg^-1 DM of Co and 20 mg kg^-1 DM of Cu. In conclusion, the supplementation of Co and Cu with different levels has no influence on vitamin B12 status. The optimum ratio of Co and Cu in diet could enhance the nutrient utilization.

Folate and vitamin B12 in idiopathic male infertility

Although methylenetetrahydrofolate reductase, a folate enzyme gene, has been associated with idiopathic male infertility, few studies have examined other folate-related metabolites and genes. We investigated whether idiopathic male infertility is associated with variants in folate, vitamin B12 （B12） and total homocysteine （tHcy）-related genes and measured these metabolites in blood. We conducted a case-control study that included 153 men with idiopathic infertility and 184 fertile male controls recruited at the Fertility Center and Antenatal Care Center, University Hospital, Malmo and Lund, Sweden. Serum folate, red cell folate （RCF）, serum B12, plasma tHcy and semen quality were measured. Subjects were genotyped for 20 common variants in 12 genes related to folate/B12/ homocysteine metabolism. Metabolite concentrations and genotype distributions were compared between cases and controls using linear and logistic regression with adjustment for covariates. The phosphatidylethanolamine N-methyltransferase （PEMT） M 175V and TCblR rs173665 polymorphisms were significantly associated with infertility （P=0.01 and P=0.009, respectively）, but not with semen quality. Among non-users of supplements, infertile men had lower serum folate concentrations than fertile men （12.89 vs. 14.73 nmoll^- 1 P=0.02）, but there were no significant differences in RCF, B 12 or tHcy. Folate, B 12 and tHcy concentrations were not correlated with any semen parameters. This study provides little support for low folate or B12 status in the pathogenesis of idiopathic male infertility. Although additional data are needed to confirm these initial findings, our results suggest that PEMTand TCbIR, genes involved in choline and B12 metabolism, merit further investigation in idiopathic male infertility.