血清叶酸和维生素B12水平与妊娠高血压综合征的相关性探讨

目的通过测定妊娠高血压综合征患者血清叶酸和维生素B12水平,探讨孕妇叶酸、维生素B12水平与妊娠高血压发生的关系。方法选择妊娠高血压孕妇25例,正常孕妇30名,正常非妊娠体检女性35名,采用化学发光免疫分析技术（CLIA）测定每组叶酸和维生素B12水平,比较各组之间的差异。结果正常孕妇组叶酸和维生素B12水平与正常体检女性组无明显差异,妊高症患者组叶酸及维生素B12水平均明显低于其他两组（P〈0.05）。结论孕妇血清叶酸和维生素B12水平可作为妊高症的预测指标,与妊高症的发生有较好的相关性。     

Importance of low serum vitamin B12 and red cell folate concentrations in elderly hospital inpatients.

To determine the functional importance of the low B12 and red cell folate concentrations repeatedly observed in the elderly 200 consecutive patients admitted to a geriatric unit were studied. Forty six of the patients had low serum concentrations of B12 (15), red cell folate (26), or both (five). Serum B12 and red cell folate concentrations correlated with mean cell volume, and serum B12 correlated with the neutrophil lobe count. Bone marrow deoxyuridine suppression was abnormal in 35% of the patients with low vitamin concentrations, but 55% of those with abnormal deoxyuridine suppression had morphologically normal bone marrow, and 73% had a normal mean cell volume. In patients with low vitamin values the deoxyuridine suppressed value correlated with the haemoglobin concentration and neutrophil lobe count. Thus synthesis of thymidylate was impaired by vitamin B12 or folate deficiency in at least 8% of newly admitted elderly patients, many of whom had normal blood counts despite the biochemical disturbance affecting haemopoiesis. A nutritionally depleted diet may have been responsible for many of the low vitamin values.     

The transcobalamin codon 259 polymorphism influences the risk of human spontaneous abortion

BACKGROUND: The remethylation cycle of methionine is folate and vitamin B(12) (cobalamin) dependent and appears to be crucial for embryonic development, probably through effects on synthesis of DNA, proteins and polyamines. Transcobalamin (TC) transports vitamin B(12) to the tissues. The objective of the present investigation was to explore the putative association between the major TC genetic polymorphism (Pro259Arg) and human spontaneous abortion. METHODS: The prevalence of the TC Pro259Arg polymorphism was determined in DNA samples from embryos that had been spontaneously aborted between the 6th and 20th week after conception, and adult controls using solid-phase minisequencing technique. RESULTS: The 259-Pro allele was significantly less frequent in the spontaneous abortion group than in the control group (42.2 and 57.0% respectively; P = 0.005), while the frequency of 259-Arg was significantly increased. There was a lower prevalence of 259-Pro homozygotes in the spontaneous abortion group compared with the control group (9.1 and 32.2% respectively; P < 0.001). CONCLUSIONS: The 259-Pro allele seems to have beneficial influences during embryogenesis, conceivably through its positive effect on vitamin B(12) intracellular bioavailability. Our results warrant additional investigations addressing the question if vitamin B(12) supplementation in addition to folic acid supplementation may prevent spontaneous abortion in women planning a pregnancy.     

中国4城市2—7岁分析人群维生素B12营养状况流行病学调查

目的了解4城市2～7岁分析人群维生素B12的营养状况。方法2007年5～9月和2008年5—10月,对2002名2～7岁分析人群进行体格检查、膳食调查、血常规检查及血清维生素B12水平测定,其中重庆市485名、北京市513名、珠海市503名、武汉市501名。结果①2002名2～7岁分析人群平均维生素B12水平（ng·L^-1）为775±312,市区（835±271）高于郊区（720±338）,P〈0．001;其中重庆市为756±220、北京市为840±414、珠海市为772±245、武汉市为736±317,地区间差异有统计学意义,P〈0．001。②2～7岁分析人群维生素B12水平性别差异不显著,P〉0．05;2—5岁组维生素B12水平随年龄增长呈降低趋势,r=-0．146,P〈0．001;5岁～组和〈7岁组维生素B12水平相近。（3）4城市分析人群维生素B12减少（〈300）检出率为4．7％。其中维生素B12缺乏（〈200）检出率为1．5％,边缘性缺乏（200—300）检出率为3．2％。重庆市、北京市、珠海市和武汉市分析人群血清维生素B12减少检出率分别为2．1％、3．9％、3．2％和9．6％。④分析人群维生素B12水平主要受膳食维生素B12摄入量的影响,P〈0．001。分析人群平均膳食维生素B12摄入量（μg·d^-1）市区（2．4±2．0）高于郊区（2．0±1．4）,P〈0．05;重庆市、北市京、珠海市和武汉市分析人群平均膳食维生素B,2摄入量分别为1．9±1．3、2．8±1．6、2．6±1．8和1．6±1．2,差异有显著统计学意义,P〈0．001。⑤分析人群维生素B12水平与Hb水平呈低度相关,P〈0．001。结论4城市分析人群存在维生素B12减少,以边缘性缺乏为主。儿童维生素B12营养状况受膳食维生素B12摄入量的影响,分析人群血清维生素B12水平何时达到成人水平有待研究。     

妊高征肾病患者血浆Hcy和血清FA、Vit B12检测的临床意义

目的:探讨了妊高征肾病患者血浆同型半胱氨酸(Hcy)和血清叶酸(FA)、维生素B12(Vit B12)水平的变化及临床意义.方法:应用放射免疫分析和免疫法测定了32例妊高征肾病和70例无肾病组及35名正常孕妇血浆Hcy和血清FA、Vit B12水平的变化.结果:妊高征肾病组和无肾病组血浆Hcy水平均非常显著地高于正常孕妇组(P＜0.01),而FA、Vit B12水平则显著地低于正常孕妇组(P＜0.01),妊高征肾病组与无肾病组亦有显著性差异(P＜0.01).结论:测定妊高征患者血浆Hcy和血清FA、Vit B12水平的变化对其病情和预后判断均具有重要的临床价值.     

Ethnic differences in lipid and lipoprotein metabolism in pregnant women of African and Caucasian origin.

AIMS--To investigate differences in serum lipid, lipoprotein and apolipoprotein concentrations in pregnant women of different ethnic origin. METHODS--Serum lipid, lipoprotein and apolipoprotein concentrations were measured in 232 women (114 Caucasians, 118 Africans/Afro-Caribbeans), who presented consecutively for screening for gestational diabetes in the third trimester of pregnancy. RESULTS--African/Afro-Caribbean pregnant women had lower serum concentrations of total cholesterol, low density lipoprotein cholesterol, triglycerides, and apolipoprotein B and higher high density lipoprotein cholesterol and Lp(a) lipoprotein concentrations compared with Caucasian women. Apolipoprotein A1 concentrations were similar in the two groups. The differences were not attributable to differences in weight, age, parity, or postload plasma glucose levels. CONCLUSION--Ethnic origin is an important determinant of serum lipid, lipoprotein and apolipoprotein concentrations during pregnancy.     

Major Determinants of Serum Homocysteine Concentrations in a Korean Population

The objective of this study was to identify the factors that determine serum homocysteine concentrations in Korean population. In a community-based study, 871 participants completed detailed questionnaires and physical examination. We found that increased age, male sex, family history of stroke, deficiencies of serum folate and vitamin B12, and elevated serum creatinine significantly increased the risk of hyperhomocysteinemia. However, hormonal and behavioral factors (smoking, alcohol drinking, coffee consumption, and sedentary time) were not associated with the risk of hyperhomocysteinemia. The risk of hyperhomocysteinemia was steeply increased in subjects with two or more risk factors among four selected risk factors (deficiencies of serum folate and vitamin B12, elevated creatinine, and family history of stroke) compared to subjects who did not have any risk factors, especially subjects over the age of 65 yr (odds ratio [OR], 33.5; 95% confidence interval [CI], 3.71-302.0 in men; OR, 39.2; 95% CI, 7.95-193.2 in women). In conclusion, increased age, male sex, family history of stroke, deficiencies of serum folate and vitamin B12, and elevated serum creatinine are important determinants of serum homocysteine concentrations with interaction effects between these factors.     

Folate and vitamin B12 status of adolescent girls in northern Nigeria

The diets of populations in many developing countries are low in folate and vitamin B12 and a deficiency of either of these vitamins results in increased risk for cardiovascular disease and neural tube defects. The rates of neural tube defects in Nigeria are among the highest reported worldwide. Since many girls marry at an early age in northern Nigeria, we therefore determined the folate and vitamin B12 status of adolescent girls between 12 and 16 years of age in Maiduguri, Nigeria. The mean serum folate concentration for subjects was 15.3 +/- 5.2 nmol/L. Whereas only four subjects (2.4%) had serum folate concentrations lower than 6.8 nmol/L, a level indicative of negative folate balance, 9% of the subjects had serum vitamin B12 concentrations at or below 134 pmol/L, the lower limit of the reference range for their age group. Serum homocysteine was measured in 56 of the 162 subjects and the mean level was 15.9 +/- 5.0 mumol/L. The majority of subjects had serum homocysteine concentrations above the upper limit of the reference range for their age group. We conclude that the adolescent girls we studied were at greater risk for vitamin B12 deficiency than folate deficiency. This conclusion is consistent with the fact that their diet included few foods that contained vitamin B12.     

Circulating concentrations of placenta protein 14 during the natural menstrual cycle in women significantly reflect endometrial receptivity to implantation and pregnancy during successive assisted reproduction cycles

Placenta protein 14 (PP14), which is the most abundant product of the secretory endometrium, has been proposed as the best biochemical marker of endometrial function in women. In this study, 19 normogonadotrophic women of infertile couples were monitored with serial measurements of concentrations of PP14, gonadotrophins and sex steroids and ultrasound scanning of endometrial thickness throughout three consecutive cycles. The first two of these were natural, unstimulated cycles (cycles 1 and 2), while ovarian stimulation with clomiphene and human menopausal gonadotrophin combined with assisted reproduction (intrauterine insemination in four cases and in-vitro fertilization in 15) was performed in the third cycle (cycle 3). A newly developed enzyme-linked immunosorbent assay was used to measure serum PP14 concentrations. In cycle 3, seven women became pregnant (group A) and 12 did not (group B). Circulating concentrations of PP14 were significantly lower in group A than in group B throughout all three cycles and in all cycle phases with exception of the late luteal phase of cycle 3, during which PP14 concentrations in group A were significantly higher than in group B. Statistical analyses showed no significant correlations between serum concentrations of PP14 and follicle stimulating hormone, luteinizing hormone and progesterone, and endometrial thickness. By contrast, serum oestradiol concentrations during the pre-ovulatory phase were significantly correlated with PP14 concentrations during the mid-luteal phase of the cycle. It is concluded that circulating PP14 is a most reliable biochemical marker of endometrial function in women and that relatively low concentrations in serum during the natural, unstimulated cycle are significantly correlated to implantation and pregnancy during successive assisted reproduction cycles. Measurement of PP14 in serum may thus be useful as a method of screening endometrial function in women, before commencing troublesome and costly treatment for infertility. However, further studies in a much larger number of women are needed to confirm this observation and to elucidate the as yet undefined physiological functions of PP14 in women.      

Vitamin A and beta-carotene levels during pregnancy in Gaziantep, Turkey

Vitamin A levels during pregnancy have important influences on the health of pregnant women and the growing fetus. Therefore, plasma vitamin A and beta-carotene concentrations during pregnancy in Turkish women living in Gaziantep city were investigated in a prevalence study. Optimum sample size was determined as 252 for vitamin A deficiency and vitamin A and beta-carotene levels were examined in 427 pregnant women aged 14-44 years. Vitamin A and beta-carotene concentrations were measured spectrophotometrically by Neeld Pearson method. Vitamin A and beta-carotene concentrations in pregnant women were found as 1.14 +/- 0.44 micromol/L, and 1.80 +/- 0.66 micromol/L, respectively. Plasma vitamin A concentrations were found in low levels (<1.05 micromol/L) in 45.5% of pregnant women. Vitamin A deficiency (<0.7 micromol/L) was determined in 16.9% of pregnant women. A mild negative correlation was obtained between the vitamin A concentration and pregnancy period. Vitamin A levels of pregnant women were decreased significantly in the third trimester (p<0.05). The findings of present study suggest that vitamin A levels of pregnant women were poor in the region. Therefore, the intake of vitamin A with foods should be improved. Supplementation of vitamin A might benefit at improving maternal and child health especially in high-risk groups especially in developing countries. Monitoring vitamin A levels in pregnant women is very important for also determining low and high levels.     

不同孕期的妊娠妇女血清SF、FA和Vit B12检测的临床意义

目的:探讨了不同孕期妊娠妇女血清铁蛋白(SF)、叶酸(FA)和维生素B12(Vit B12)水平的变化及意义.方法:应用放射免疫分析对132例不同孕期的妊娠妇女进行了血清SF、FA和Vit B12的水平检测,并与35名正常妇女进行比较.结果:除早孕组血清SF、FA、Vit B12水平与正常人比较无显著差异外,其余各组均有显著性差异(P＜0.01).结论:检测不同孕期的妊娠妇女血清SF、FA和Vit B12水平的变化对了解病情、指导临床实践均有十分重要的临床价值.     

Evaluation of the relationship between serum levels of zinc,vitamin B12, vitamin D,and clinical outcomes in patients with COVID-19

Due to the known anti-inflammatory and antiviral effects of zinc, 25(OH)D, and vitamin B12, in this study, we explored the association between serum levels of these micronutrients in coronavirus disease 2019 (COVID-19) patients at the time of admission and the clinical outcomes. This study was carried out on 293 patients with COVID-19, who were hospitalized at Imam Hassan hospital (Bojnourd, Iran). We collected demographic data, clinical characteristics, values of serum biochemical parameters in the first week of admission, and clinical outcomes from electronic medical records. We also measured serum levels of zinc, 25(OH)D, and vitamin B12 within 3 days of admission. Of the 293 hospitalized, the median age was 53 years, and 147 (50.17%) were female. Thirty-seven patients (12.62%) were admitted to the intensive care unit (ICU), and forty-two (14.32%) died. We found that the serum levels of zinc, vitamin B12, and 25(OH)D were lower in patients who died than those who were admitted to ICU or non-ICU and survived; however, these differences were not statistically significant for vitamin B12 and 25(OH)D (p > 0.05). The serum concentrations of zinc, vitamin B12, and 25(OH)D at the time of admission did not affect the length of hospital stay in patients with COVID-19. In general, it seems that serum levels of 25(OH)D, vitamin B12, and especially zinc at the time of admission can affect clinical outcomes in COVID-19 patients.     

Correlations between holo-transcobalamin II, holo-haptocorrin, and total B12 in serum samples from healthy subjects and patients.

AIMS--To study the correlations between total vitamin B12(B12), holo-haptocorrin, and holo-transcobalamin II (holo-TCII) concentrations in human sera; the association between reduced holo-TCII concentrations and macrocytosis attributable to B12 deficiency. METHODS--Serum samples from 38 healthy volunteers, 113 patients with normal total serum B12 concentrations and 93 patients with low total serum B12 were studied. Holo-TCII was removed from whole serum by adsorption with amorphous precipitated silica, and both whole serum and adsorbed serum were assayed for B12 using the Becton Dickinson vitamin B12 [57Co] radioassay kit. RESULTS--In all three groups of subjects studied there were strong correlations between the logarithms of the total serum B12 and the holo-haptocorrin concentrations with regression coefficients between 0.884 and 0.967. By contrast, the correlations between the logarithms of the total serum B12 and holo-TCII concentrations were weaker, especially in the patients with normal or low total serum B12, for whom the regression coefficients were 0.491 and 0.391, respectively. Analysis of the clinical records of a proportion of the patients studied indicated that there were many more patients with low holo-TCII concentrations than with haematological disturbances related to B12 deficiency. CONCLUSIONS--The total serum B12 concentration is a relatively poor indicator of holo-TCII concentrations and, therefore, of the ability of serum to deliver B12 to tissues. Additional information regarding B12 values can therefore be gleaned from measuring holo-TCII concentrations in the serum. Low holo-TCII concentrations, however, are an early sign of negative B12 balance and are frequently unassociated with haematological abnormalities caused by B12 deficiency.     

Serum levels of folate and cobalamin in women with recurrent spontaneous abortion

We evaluated the folate and cobalamin status in 29 non-pregnant women with a history of recurrent spontaneous abortion (three or more consecutive) of unknown aetiology in comparison to 29 healthy nulligravidae of similar reproductive age (controls). Serum concentrations of folate and cobalamin showed no significant differences between the two groups. No correlation between age and vitamin concentrations was found. In the study group there was a significant negative correlation of the number of previous abortions and the concentration of serum folate. Patients with at least four previous miscarriages had significantly lower serum values of folic acid than women with three abortions, but not than controls. The underlying cause of this finding remains unclear. In conclusion, the serum concentrations of folic acid and vitamin B12 are not significantly altered in women with unexplained recurrent spontaneous abortions, and an association between a deficiency of these vitamins and an increased risk of pregnancy loss appears to be questionable in the majority of gestations.      

Genetic and lifestyle factors related to the periconception vitamin B12 status and congenital heart defects: a Dutch case-control study

Maternal hyperhomocysteinemia is associated with congenital heart defects (CHDs) in the offspring. A low periconception vitamin B12 status is determined by genetic and lifestyle factors and causes hyperhomocysteinemia. We investigated methionine synthase reductase (MTRR) and transcobalamin II (TC) genes and maternal intake and serum concentrations of vitamin B12 in association with CHD risk. Seventeen months after the index-pregnancy, we studied 230 children with a CHD and 251 non-malformed children and their parents. Data were collected on current and periconception maternal vitamin supplement use and maternal dietary vitamin B12 intake of the month before the study moment. Blood samples were taken for the determination of MTRR A66G and TC C776G genotypes in families and maternal serum vitamin B12 concentrations. Transmission disequilibrium tests and univariate and multivariate analyses were applied. Allele transmissions were not significantly distorted. The MTRR and TC genotypes did not significantly affect CHD risk. Neither polymorphisms in mothers and/or children revealed significant interactions nor in combination with low vitamin B12 intake. Low maternal serum vitamin B12 combined with the maternal or child's MTRR 66 GG genotype resulted in odds ratios of 1.4 (95% confidence interval 0.6-3.5) and 1.3 (0.5-3.4), respectively. The TC 776 GG genotype in mothers and children revealed risk estimates of 2.2 (0.7-7.1) and 1.9 (0.5-7.4), respectively. In conclusion, MTRR 66 GG and TC 776 GG genotypes in mothers and children may contribute to the risk of CHDs, particularly when the maternal vitamin B12 status is low. The future enlargement of our sample size might demonstrate significant associations.     

Prevalence of suboptimal vitamin D status during pregnancy

Low maternal vitamin D status has been associated with reduced intrauterine long bone growth and shorter gestation, decreased birth weight, as well as reduced childhood bone-mineral accrual. Despite data from other countries indicating low maternal vitamin D status is common during pregnancy, there is a dearth of information about vitamin D status during pregnancy in the Irish female population. Therefore, we prospectively assessed vitamin D nutritive status and the prevalence of suboptimal vitamin D status in a cohort of Irish pregnant women. The mean (SD) daily intake of vitamin D by the group of pregnant women was 3.6 (1.9) microg/day. None of the women achieved the recommended daily vitamin D intake value for Irish pregnant women (10 microg/day). Taking all three trimesters collectively, 14.3-23.7% and 34.3-52.6% of Irish women had vitamin D deficiency (serum 25 (OH) D <25 nmol/l) and insufficiency (serum 25 (OH) D 25-50 nmol/l), respectively during pregnancy. Both the levels of serum 25 (OH) D and the prevalence of vitamin D deficiency/adequacy were dramatically influenced by season, with status being lowest during the extended winter period and best during the extended summer period. These findings show that inadequate vitamin D status is common in Irish pregnant women.     

Lipid, glucose and homocysteine metabolism in women treated with a GnRH agonist with or without raloxifene

BACKGROUND: Although GnRH analogues are widely used to treat a variety of sex hormone-related diseases, little is known about their effect on metabolism. Therefore, we have evaluated the effect of a GnRH analogue, administered with or without raloxifene, on serum levels of lipoproteins, glucose, insulin and homocysteine (Hcy). METHODS: One hundred premenopausal women with symptomatic uterine leiomyomas were initially enrolled and randomized to receive 3.75 mg/28 days leuprolide acetate depot associated with 60 mg/day raloxifene hydrochloride (group A) or 1 placebo tablet/day (group B) for six cycles of 28 days. At entry and at cycle 6, subjects underwent anthropometric measurements, including body mass index and waist-to-hip ratio measurements, and blood chemistry assays for serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), glucose, insulin, Hcy, vitamin B(12) and folate concentrations. Insulin resistance was evaluated with the homeostasis model assessment (HOMA) score. RESULTS: Baseline parameters were similar in the two groups. At cycle 6, TC, HDL-C, LDL-C and TG levels were significantly increased (P < 0.05) in group B. In group A, LDL-C levels were unchanged, and TC, HDL-C and TG levels were increased (P < 0.05). Serum TC and LDL-C levels differed (P < 0.05) between the groups. Glucose levels were unchanged between and within groups, whereas insulin levels and HOMA scores increased (P < 0.05) versus baseline in group B. Post-treatment Hcy levels were higher (P < 0.05) versus baseline in group B; they were unchanged in group A. Serum vitamin B(12) and folate concentrations were unchanged in both groups. CONCLUSIONS: GnRH analogues alter serum lipoprotein and Hcy levels and increase insulin resistance. These acute metabolic changes may be prevented or reduced by raloxifene.     

Serum YKL‐40 and gestational diabetes – an observational cohort study

To examine serum YKL‐40 in women developing gestational diabetes mellitus (GDM). In the present large observational cohort study of 1179 pregnant women, we determined serum YKL‐40 four times during pregnancy (at gestational age 12, 20, 25, and 32 weeks). Pregnancy outcome was obtained from medical records. Sixty‐eight women (5.8%) developed GDM. Serum YKL‐40 increased from gestational age (GA) 12 weeks and the following weeks in the women who developed GDM and was independent of BMI, parity, and maternal age (OR = 2.69, 95% CI: 1.45–5.00, p = 0.002). No association was found between serum YKL‐40 and the oral glucose tolerance test results. In conclusion, YKL‐40 significantly increased in pregnant women with GDM compared with women without GDM, probably reflecting the low‐grade inflammation of GDM. However, we did not find an association between serum concentrations of YKL‐40 in early pregnancy and the development of GDM and thus we conclude that YKL‐40 alone is not usable as a biomarker for early prediction of GDM.     

Serum adiponectin and lipid concentrations in pregnant women with polycystic ovary syndrome

BACKGROUND: We aimed to evaluate the serum adiponectin and lipid concentrations in normal and polycystic ovary syndrome (PCOS) women during pregnancy in order to establish whether PCOS induces abnormal lipid and adiponectin levels that could constitute potential metabolic risk factors for pregnancy complications. METHODS: Women with singleton pregnancies and of similar age were included (48 pregnant PCOS and 51 normal pregnant women). During gestational weeks 10-16 and 22-28, a 2 h, 75 g oral glucose tolerance test was performed, with measurement of glucose and insulin in each sample. Adiponectin and lipid concentrations were determined in the fasting sample. RESULTS: The incidence of gestational diabetes mellitus (GDM) was significantly higher in the PCOS group (12.2%) compared with the control group (2%). In PCOS patients, triglyceride (TG) concentrations and area under the curve of glucose and insulin were higher in both study periods and adiponectin concentrations were significantly lower in the second period, compared with normal women. Moreover, adiponectin concentrations were lower in women with GDM than in those with normal glucose tolerance in the two study periods. CONCLUSION: Low adiponectin and high insulin levels are associated with GDM in pregnant PCOS patients. High TG levels seem not to be directly related to pregnancy complications in these patients.     

Effect of antimicrobial agents on the Euglena method of serum vitamin B12 assay

Antimicrobial agents in the serum may affect the results of the Euglena method of serum vitamin B(12) assay. Sulphonamides suppress the growth of Euglena in concentrations attainable in the serum during treatment; streptomycin, chlortetracycline, erythromycin, kanamycin, and nitrofurantoin bleach Euglena but only when present in concentrations far exceeding the normal peak therapeutic blood levels. False low results of serum vitamin B(12) assay due to inhibitory and/or bleaching substances in the serum can be readily detected by microscopy of the assay cultures and Euglena cell counts.