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Search Results: 1 - 10 of 18811 matches for " B12 vitamin "
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Vitamin B12 in pregnancy: Maternal and fetal/neonatal effects—A review  [PDF]
H. Van Sande, Y. Jacquemyn, N. Karepouan, M. Ajaji
Open Journal of Obstetrics and Gynecology (OJOG) , 2013, DOI: 10.4236/ojog.2013.37107
Abstract:

Vitamin B12 maintains normal folate metabolism which is essential for cell multiplication during pregnancy. No good data are available on what constitutes vitamin B12 deficiency in pregnancy, nevertheless vitamin B12 deficiency is frequently reported in pregnancy due to inadequate dietary intake of vitamin B12 and a physiological decline of maternal vitamin B12 concentrations. This decline can be explained by the increased maternal metabolic rate and active transport by the placenta to the fetus. If the mother is deficient during pregnancy, the baby may have low serum vitamin B12 concentrations at birth [1]. Vitamin B12 deficiency during pregnancy is associated with preeclampsia, fetal growth restriction, preterm labor, neural tube defects, neonatal megaloblastic anemia and neonatal neurological symptoms. It has been suggested to improve vitamin B12 status of women in the periconceptional period by supplementation of vitamin B12, but no randomized studies on the outcome of such supplementation have been published.

Status of Vitamin B12 Deficiency in the Elderly Chinese Community People  [PDF]
Yuhui Wang, Yunyun Zheng, Fang Yan, Wenbo Zhang
Health (Health) , 2015, DOI: 10.4236/health.2015.712185
Abstract: This study was aimed to investigate the vitamin B12 deficiency prevalence and symptoms in elderly people lived in a community of Shanghai, China. A total number of 962 elderly people resided in Shanghai community were recruited in the present study. They were 60 years and older, and the average age was 76.38 ± 13.68 years old. Information on previous and present diseases, currently prescribed and over-the-counter medication, and the presence or absence of symptoms relating to vitamin B12 deficiency were obtained by questionnaire. The levels of serum vitamin B12, folate and homocysteine (Hcy) were estimated. The patients with vitamin B12 deficiency were screened. The results of symptoms and positive signs of neurological examination were compared between subjects with or without vitamin B12 deficiency. The results showed that vitamin B12 deficiency was found in 130 persons (13.53% of the total subjects), with an increase in incidence with aging, only 10% of the vitamin B12 deficient subjects had megaloblastic anemia. The reported symptoms of vitamin B12 deficient subjects included fatigue, memory decline, dizziness, unsteadily walking in the darkness and hypopallesthesia. In conclusion, vitamin B12 deficiency was remarkably common in Chinese elderly people, with various and atypical clinical manifestations, and the neurological symptoms were more common than those of megaloblastic anemia.
Vitamin B12 Screening in Cervical Spine Surgery Patients  [PDF]
Abdullah Tolaymat, Moataz Abbara, M. Sami Walid, Mohammed Ajjan, Joe Sam Robinson Jr
Neuroscience & Medicine (NM) , 2011, DOI: 10.4236/nm.2011.22021
Abstract: Introduction Vitamin B12 is very vital for the nervous system. Its deficiency can manifest with neurological symptoms like pain and paresthesias and in severe cases may cause not completely restorable neurological damage, especially in elderly patients. Methods The charts of 702 patients who underwent cervical spine surgery retrospectively reviewed and data collected . All patients were preoperatively seen by an internist who ordered Vit B12 levels for some of them. We used two thresholds for the diagnosis of vitamin B12 deficiency, 200 and 300 pg/mL as recommended by Yao et al. 1992. Data were also collected on gender, payor status, myelopathy, hemoglobin level, corpuscular parameters and glycosylated hemoglobin level (HbA1c). Vitamin B12 levels were compared between patients with HbA1c levels ≥ 6.1% and <6.1%. Differences between patients ≥ and < than the median age were studied. The median age of the patient cohort was 52. Results Hemoglobin level was recorded for 659 patients. Vit B12 levels were ordered for 291 patients only. Overall, 13.7% had decreased hemoglobin level (anemia), 30.2% had decreased Vit B12 levels by the 300 threshold, 6.9% had decreased Vit B12 levels by the 200 threshold, 6.3% decreased MCV (microcytosis), and 2.8% increased MCV (macrocytosis). Only four patients (0.7%), of whom older than 52, had decreased hemoglobin level and increased MCV (macrocytic anemia) and one patient (0.4%), who was also older than 52, had decreased hemoglobin level, increased MCV and Vit B12 level < 200 pg/mL (macrocytic anemia duo to Vit B12 deficiency). Dividing the patient sample into three age groups, <40, 40-59, and ≥ 60 years, we investigated the trend of cobalamin deficiency by age and found an increase in cobalamin deficiency after 40 from 0% to 7.4% (200 threshold). Uninsured patients (25%) using the 200 pg/mL threshold and workers’ compensation (54.5%) and uninsured patients (50.0%) had the highest rate of Vit B12 deficiency using the 300 pg/mL threshold. The few patients with macrocytic anemia (N=4) and macrocytic anemia due to Vit B12 deficiency (N=1) had health coverage. Conclusion Vit B12 deficiency in cervical spine surgery patients may not necessarily mean macrocytic anemia but may precede macrocytic anemia. Therefore, Vit B12 deficiency screening on the preoperative visit is warranted especially in uninsured or older patients or both. Preoperative treatment may be indicated and correlation with postoperative outcome is suggested for future research.
Methylmalonic acid as an indicator of vitamin B12 deficiency in patients on metformin  [PDF]
Norbert Shtaynberg, Manjinder Singh, Phillip Sohn, Michael Goldman, Neil Cohen
Journal of Diabetes Mellitus (JDM) , 2012, DOI: 10.4236/jdm.2012.21011
Abstract: Context: Metformin is frequently prescribed for the treatment of type 2 diabetes mellitus. It is recommended as a first line agent by the American Diabetes Association. Vitamin B12 deficiency has been suggested as a side effect of metformin therapy; however, previous studies have not assessed the utility of methylmalonic acid levels as an indicator of vitamin B12 status. Objective: To investigate the prevalence of vitamin B12 deficiency in patients on metformin therapy for diabetes by utilizing both vitamin B12 and methylmalonic acid levels. Design, Setting, and Patients: Eighty-eight patients with diabetes, who were either on or off metformin therapy for at least thirty days, were enrolled in a case-controlled study. Blood work and questionnaires were used for analysis. Main Outcome Measures Study: Aims were to detect a clinically significant difference in the prevalence of vitamin B12 deficiency between metformin users and non-users, where such deficiency is defined by both low vitamin B12 and elevated methylmalonic acid levels. Results: Two Sample Equal Variance T-Tests were used to compare averages of measured values and the Chisquare test was used to determine the significance of calculated vitamin B12 deficiency rates between the two groups of patients. Two separate methods for defining vitamin B12 deficiency were utilized. There was no difference in the prevalence of vitamin B12 deficiency in metformin users compared with non-users by either method. Average homocysteine levels were higher in those not on metformin therapy. Conclusion: Vitamin B12 deficiency as defined by an elevated methylmalonic acid level was no greater in patients with diabetes on metformin therapy versus those patients not on metformin treatment.
M.C.V. should not be the only criteria to order vitamin B12 for anemia under evaluation  [PDF]
Rohit Jain, Menka Kapil, Gajendra Nath Gupta
Open Journal of Gastroenterology (OJGas) , 2012, DOI: 10.4236/ojgas.2012.24037
Abstract: Introduction: A strict vegetarian diet has been associated with increased risk of cobalamin deficiency therefore; one would expect a high prevalence of Cobalamin deficiency in India. Erythrocyte indices have been used in the initial evaluation of anemic patients; high Mean corpuscular volume (MCV) is a traditional criterion for folate and vitamin B12 deficiencies. There is no large study of the prevalence of B12 deficiency among patients with normocytosis or micro-cytosis. Method: We retrospectively analyzed the records of serum vitamin B12 and MCV of both inpatients and outpatients at Santokba Durlabhji Memorial Hospital & Research Institute, Jaipur (Rajasthan) during the period from August 2010-April 2011. The study was aimed at identifying the correlation between vitamin B12 level and MCV; and prevalence of vitamin B12 deficiency in this region. Result & Conclusion: Every third person is vitamin B12 deficient in the region. There is no correlation between vitamin B12 levels and MCV in majority of the cases. MCV should not be the only criteria for ordering vitamin B12 for patients with anemia under evaluation.
Deficiencia de vitamina B12: tratamiento oral o parenteral
Forrellat Barrios,Mariela; Hernández Ramírez,Porfirio;
Revista Cubana de Hematolog?-a, Inmunolog?-a y Hemoterapia , 2009,
Abstract: traditional treatment of vitamin b12 deficiency has been the cobalamin administration via periodic intramuscular injections following different rules depending from deficit severity and clinical picture present. despite that from 50s and 60s of past century, it was established that oral b12 therapy is as effective as injections ones in treatment of this type of deficiency, in practice it looks like a not very accepted fact. researches aimed to assess this alternative, and why still its use has not been completely understood, suggest that the change to a vitamin b12 treatment implicates significant savings in terms of financial costs, time of physicians and health staff, and the drawbacks and annoyances for patients, whom in general, accept well the change of therapy.
The role of holotranscobalamin in examination of vitamin B12 status
?abarkapa Velibor,Sto?i? Zoran,Uzurov Vera,Saka? Vladimir
Medicinski Pregled , 2008, DOI: 10.2298/mpns0808389c
Abstract: Introduction. Holotranscobalamin contains biologically available cobalamin because only holotranscobalamin promotes the uptake of the cobalamin therein by all cells, via specific receptors. Therefore holotranscobalamin has been proposed as a potentially useful alternative indicator of vitamin B12 status. The aim of the present study was to assess usefulness of holotranscobalamin in the evaluation of vitamin B12 status. Material and methods. We examined serum level of holotranscobalamin in 135 subjects divided in four groups according to the serum concentration of vitamin B12: 30 subjects with vitamin B12<154 pmol/l, 50 subjects with vitamin B12 154-250, 30 subjects with vitamin B12 251-350 pmol/l, 25 subjects with vitamin B12>350 pmol/l. Results The results show that in subjects with low vitamin B12 serum level there are those with normal holotranscobalamin concentration (60%) and that in subjects with normal vitamin B12 there are those with low holotranscobalamin concentration (22%). The obtained results also show positive significant correlation between levels of holotranscobalamin and vitamin B12 (r=0.62, p<0.001). Conclusion. We can conclude that biologically active cobalamin, holotranscobalamin, is a useful tool when examining vitamin B12 status especially in subjects with borderline and low vitamin B12 concentrations. Measurements of the serum holotranscobalamin may be superior to total serum cobalamin.
The Importance of Holotranscobalamin Measurement
Velibor abarkapa, Zoran Sto i , Radmila eravica, Branislava Ilin i , Ana Filipovi
Journal of Medical Biochemistry , 2007, DOI: 10.2478/v10011-007-0027-3
Abstract: Clinically significant vitamin B12 deficiency can occur even with total vitamin B12 levels apparently within normal range. There is an indeterminate zone between approximately 154 and 300 pmol/L of vitamin B12 where there is likely misclassification of B12 status if relying on total serum B12. The aim of the present study was to assess the usefulness of holotranscobalamin in diagnosis of B12 deficiency. Blood samples were collected and subjected to assays for vitamin B12 and holotranscobalamin. We examined the levels of holotranscobalamin in 32 subjects (n=32, f=18, m=14) with vitamin B12 values within interval 154-300 pmol/L. These subjects were compared with control group with vitamin B12>300 pmol/L (n=31, f=17, m=14). 25% of subjects with vitamin B12 of 154 to 300 pmol/L had low levels of holotranscobalamin. Holotranscobalamin levels of patients with vitamin B12 of 154 to 300 pmol/L were significantly lower than those of control subjects (38.55 ± 23.0 vs. 61.35 ± 31.81 pmol/L, p<0.01). The obtained results also show a positive significant relationship between levels of holotranscobalamin and vitamin B12 (r=0.53, p<0.01). In conclusion, holotranscobalamin is a better indicator of early vitamin B12 deficiency than total serum cobalamins and it is a useful tool in the diagnosis of vitamin B12 deficiency.
Vitamin B12: Unique Metalorganic Compounds and the Most Complex Vitamins
Lucio Randaccio,Silvano Geremia,Nicola Demitri,Jochen Wuerges
Molecules , 2010, DOI: 10.3390/molecules15053228
Abstract: The chemistry and biochemistry of the vitamin B12 compounds (cobalamins, XCbl) are described, with particular emphasis on their structural aspects and their relationships with properties and function. A brief history of B12, reveals how much the effort of chemists, biochemists and crystallographers have contributed in the past to understand the basic properties of this very complex vitamin. The properties of the two cobalamins, the two important B12 cofactors Ado- and MeCbl are described, with particular emphasis on how the Co-C bond cleavage is involved in the enzymatic mechanisms. The main structural features of cobalamins are described, with particular reference to the axial fragment. The structure/property relationships in cobalamins are summarized. The recent studies on base-off/base-on equilibrium are emphasized for their relevance to the mode of binding of the cofactor to the protein scaffold. The absorption, transport and cellular uptake of cobalamins and the structure of the B12 transport proteins, IF and TC, in mammals are reviewed. The B12 transport in bacteria and the structure of the so far determined proteins are briefly described. The currently accepted mechanisms for the catalytic cycles of the AdoCbl and MeCbl enzymes are reported. The structure and function of B12 enzymes, particularly the important mammalian enzymes methyltransferase (MetH) and methyl-malonyl-coenzymeA mutase (MMCM), are described and briefly discussed. Since fast proliferating cells require higher amount of vitamin B12 than that required by normal cells, the study of B12 conjugates as targeting agents has recently gained importance. Bioconjugates have been studied as potential agents for delivering radioisotopes and NMR probes or as various cytotoxic agents towards cancer cells in humans and the most recent studies are described. Specifically, functionalized bioconjugates are used as “Trojan horses” to carry into the cell the appropriate antitumour or diagnostic label. Possible future developments of B12 work are summarized.
Evaluation of Serum Trace Elements and Vitamin Levels in Hashimoto’s Thyroiditis: Single Centre Experience from Turkey  [PDF]
Fatma Dilek Dellal, Mutlu Niyazoglu, Esranur Ademoglu, Suheyla Gorar, Zehra Candan, Handan Bekdemir, Ziynet Alphan Uc, Mehmet Senes, Aysenur Ozderya, Yalcin Aral
Open Journal of Endocrine and Metabolic Diseases (OJEMD) , 2013, DOI: 10.4236/ojemd.2013.34031
Abstract:

Aim: To determine levels of serum trace elements and vitamins, and to find out possible correlations between these elements and vitamins with thyroid function tests and thyroid autoantibody levels in patients having Hashimoto’s thyroiditis (HT). Methods: The study included 51 premenauposal women with untreated HT, aged 18 to 56 years without any known chronic diseases or chronic medicine usage, and 27 healthy premenauposal women aged 19 to 42 years old. Trace elements (selenium, zinc, copper, iron levels) and vitamins [A, E, B12, 25-OH-D, 1,25(OH)2D and folic acid levels] were evaluated in patient and control groups. Results: Consequently, serum trace elements and vitamin B12 levels did not significantly differ in patients with HT and control group. Thyroid functioning tests and autoantibody levels did not show any correlation with the levels of trace elements, vitamin A, vitamin E and 25-OH vitamin D. A correlation was detected between vitamin B12 and Anti thyroid peroxidase levels. Conclusion: The negative correlation between vitamin B12 and Anti thyroid peroxidase levels may demonstrate the necessity to screen the patients with HT for atrophic gastritis. We believe that more comprehensive studies with larger sample sizes are needed in which patients are randomized according to their nutritional status.

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