中老年脑白质疏松症同型半胱氨酸叶酸及维生素B12测定的临床意义

目的 探讨中老年脑白质疏松症(leukoaraiosis,LA)与同型半胱氨酸(Homocysteine,Hcy)、叶酸及维生素B12的相关性.方法 选择CT、MRI证实的中老年LA患者30例,测定其血浆总Hcy、血清叶酸及维生素B12水平,与对照组比较.结果 中老年LA患者血浆总Hcy升高,血清叶酸、维生素B12降低,与对照组相比差异有统计学意义(P＜0.001),即Hcy水平与中老年LA呈正相关,叶酸、维生素B12水平与中老年LA呈负相关.结论 Hcy、叶酸及维生素B12与中老年LA具有相关性,是中老年LA的重要危险因素.     

维生素B12缺乏引起中枢及周围神经变性15例临床分析

目的探讨维生素B12缺乏导致的神经系统疾病的发病特点、临床分型.方法对15例维生素B12缺乏的患者的临床资料进行回顾性分析.结果维生素B12缺乏患者神经系统的症状主要表现为肢体感觉异常、深感觉减退、共济失调及痉挛性轻瘫等,早期易误诊,其病理改变是髓鞘缺失,脱髓鞘的部位可以在中枢神经系统,也可以在周围神经系统.结论维生素B12缺乏引起的神经系统疾病除脊髓脱髓鞘外,还可引起大脑白质、脑干及周围神经脱髓鞘改变.     

水溶性维生素的毛细管电泳测定

建立了高效毛细管电泳同时测定水溶性维生素制剂中的维生素B1、维生素B2、维生素B6、维生素B12、维生素C、烟酸、烟酰胺等的方法.缓冲液为0.02mol/L的硼酸溶液,毛细管为50μm×50cm,检测波长为190nm(适用于维生素B1、维生素B6、维生素B12、烟酸、烟酰胺)和265nm(适用于维生素B2、维生素C),分离度高,方法简便.     

慢性脊柱疾病患者筛查亚急性脊髓联合变性的临床研究

目的 评价血清维生素B12检测在筛查慢性脊柱疾病患者中亚急性脊髓联合变性(SCD)发病情况.方法 选取慢性脊柱疾病患者1256例,常规进行血清维生素B12检查及病变部位MRI检查,排除SCD患病情况.结果 1256例患者中血清维生素B12异常者34例,其中升高9例,降低25例.维生素B12升高的9例均排除SCD(维生素B12中位数为1128.3 pg/ml),维生素B12降低患者中最终确诊SCD 3例(维生素B12中位数为87.4 pg/ml),血清维生素B12正常患者中通过其他手段确诊SCD 1例.结论 检测血清维生素B12对于大规模慢性脊柱疾病患者筛查SCD具有一定临床意义.     

心绞痛患者同型半胱氨酸药物干预试验研究

目的观察心绞痛患者同型半胱氨酸（Hcy）水平与叶酸、维生素B6、维生素B12浓度之间的关系,并希望在常规治疗的基础上加用叶酸、维生素B6和维生素B12的方法可以降低心绞痛患者高Hcy血症,进而达到降低心绞痛患者的发病率及心肌梗死率。方法对心绞痛患者及健康对照者采用酶联免疫吸附试验法测定空腹血清Hcy水平,应用放射免疫标记法测定基础血清叶酸及维生素B12浓度,高效液相色谱法测定血清总维生素B6水平。对于Hcy水平高于15μmol.L-1者诊断为高同型半胱氨酸血症。随机抽取24例心绞痛患者作为服药心绞痛组和16例正常人群作为服药正常人对照组,予以补充叶酸5 mg.次-1,1次.d-1;维生素B620 mg.次-1,3次.d-1;维生素B120.1 mg.次-1,1次.d-1。在服药前和服药后10-12周后复查血浆Hcy、叶酸、维生素B6、维生素B12水平。另抽取未服药的10例心绞痛患者测定血清Hcy、血清叶酸、维生素B12和维生素B6水平,10-12周后复查,作为未服药心绞痛对照组。结果心绞痛患者血浆Hcy水平高于正常组,基础叶酸浓度明显低于正常组,直线相关分析结果显示心绞痛患者组血清Hcy水平与基础叶酸浓度呈明显负相关（P〈0.001）,服药心绞痛组加叶酸、维生素B6、维生素B12治疗后Hcy水平明显低于治疗前（P〈0.001）。结论心绞痛患者Hcy水平较正常对照组显著升高,常规治疗基础上联合补充叶酸、维生素B6和维生素B12后可明显降低心绞痛患者血浆Hcy水平。     

紫外分光光度法测定维生素B_(12)注射液含量的不确定度分析

目的通过对维生素B12注射液含量测定结果的不确定度评定,建立紫外-可见分光光度法测定维生素B12注射液含量的不确定度分析方法。方法分析来自各溶液配制过程和仪器测定过程的各种不确定度影响因素并对其进行评估。结果建立紫外-可见分光光度法测定维生素B12注射液含量的不确定度的数学模型,计算各变量的不确定度,由此计算合成不确定度,最终给出测定结果的相对扩展不确定度。结论建立的不确定分析方法适用于紫外-可见分光光度法测定维生素B12注射液含量的不确定度评定。     

脊髓亚急性联合变性1例报道

<正>脊髓亚急性联合变性(subacute combined degeneration of spinal cord,SCD)是由于维生素B12缺乏导致的神经系统变性,病变主要累及脊髓后索、侧索及周围神经。本病的发生与维生素B12缺乏密切相关。维生素B12是核蛋白合成及髓鞘形成必需的辅酶,其缺乏引起髓鞘合成障碍导致神经病变。维生素B12还参与血红蛋白的合成,其缺乏常引起恶性贫血。维生素B12摄取、吸收、结合与转运的任何一个环节出     

不同剂量叶酸及维生素B12治疗高同型半胱氨酸血症疗效分析

目的 观察不同叶酸和维生素B12联合治疗脑卒中合并高同型半胱氨酸(Hcy)血症的疗效.方法收集150脑卒中合并高Hcy血症患者,随机分为A、B、C 3组,每组50例.使用不用剂量叶酸和维生素B12治疗:A组给予叶酸0.4 mg/d、维生素B12 0.5 mg/d,B组给予叶酸5 mg/d、维生素B12 0.5 mg/d,C组给予叶酸15 mg/d、维生素B12 1.5 mg/d.分别在治疗前及治疗后4周、12周检测血浆Hcy浓度,观察降Hcy有效率.结果 治疗前各组Hcy水平及一般情况无差异,治疗4周及12周后2组Hcy水平均下降,但A组Hcy水平高于B、C 2组,降Hcy有效率低于B、C 2组,差异有统计学意义(P<0.05),B、C 2组差异无统计学意义(P>0.05);治疗12周C组的治疗依从性较差.结论 叶酸5 mg/d、维生素B12 0.5 mg/d联合治疗脑卒中合并的高Hcy血症疗效更好.     

血清维生素B_(12)浓度与脑梗死的关系

目的探讨血清维生素B12浓度水平与脑梗死的关系及其临床意义。方法采用电化学发光免疫分析技术测定400例脑梗死患者和400例健康人血清维生素B12的水平。结果脑梗死患者血清维生素B12水平明显低于对照组(P<0.01)。并且若患者脑梗死病变程度越重,其血清中维生素B12水平则越低。重型与中型、重型与轻型脑梗死患者之间血清中维生素B12水平差别均有显著性统计学意义(P<0.01),中型与轻型的患者之间维生素B12水平差别无统计学意义(P>0.05)。结论血清维生素B12水平降低与脑梗死的发生有一定的相关性,应该予以监测。     

妈妈和宝宝不可缺少的B族维生素

B族维生素在体内蛋白质合成的过程中起着重要的作用。机体摄取的营养物质转变为能量的过程也离不开B族维生素。B族维生素指的是一组维生素,包括叶酸、维生素B_1、维生素B_2、维生素B_(12)。那么这一组维生素各自具有什么功能呢?     

Vitamin B12-mediated transport: a potential tool for tumor targeting of antineoplastic drugs and imaging agents

The uptake of vitamin B12 (cyanocobalamin, Cbl/VB12) in mammalian cells is mediated by specific, high-affinity receptors for the vitamin B12-binding protein, transcobalamin II, which is expressed on the plasma membrane. The receptor for vitamin B12 is overexpressed on a number of human tumors, including cancers of the ovary, kidney, uterus, testis, brain, colon, lung, and myelocytic blood cells. Furthermore, the affinity of cyanocobalamin conjugates for cell surface transcobalamin II receptors seems to be high enough so that vitamin B12 derivatization with the cytotoxic agent or carriers bearing cytotoxic drugs allows the selective delivery of diagnostic and therapeutic agents to cancer cells. Thus, conjugates of vitamin B12 enter receptor-expressing cancer cells via receptor-mediated endocytosis, and targeting may be accomplished by multiple mechanisms, depending on the drug-delivery strategy. This review summarizes the applications of vitamin B12 as a targeting ligand and highlights the various methods being developed for delivery of therapeutic and imaging agents to cancer cells in vitro and in vivo. This review reflects the potentiality of vitamin B12 for tumor targeting of chemotherapeutic and diagnostic agents.     

不同厂家复合维生素B片中维生素B_2的溶出度考察

目的利用维生素B2在紫外光444nm处有最大吸收,监测复合维生素B中维生素B2的溶出度,通过定时测量溶出量反映出不同厂家药片的质量差异。方法以醋酸盐缓冲液(pH4.3)为溶出介质,以紫外分光光度法在444nm处检测吸收值,进行溶出量监测。结果 11个厂家的溶出曲线不相似,真实的反映了各厂家之间药物溶出的差异。结论以醋酸盐缓冲液(pH4.3)为溶出介质可直接检测各厂家的维生素B2的溶出量,反映各厂家的质量,同时也可为复合维生素B片中维生素B2的质量控制提供检验依据。     

漫反射FT-IR法测定复合维生素B片剂中维生素B2的含量

目的：建立复合维生素B片剂中维生素B2含量的检测方法。方法：采用中红外漫反射定量分析技术,潮定了复合维生素B片剂中维生素B2的含量。结果：可直接测定出样品中维生素B2的含量,且吸光度与维生素B2的质量百分数成良好的线性关系,平均回收率为99．79％,RSD为1.85％。结论：本方法准确、可靠,可用于复合维生素B片剂中维生素B2的含量测定。     

维生素B_(12)片鉴别(2)出现假阴性反应的原因分析

目的提高维生素B12片鉴别(2)的检验准确性。方法分析维生素B12片鉴别(2)出现假阴性反应的影响因素。结果共有7种影响因素。结论只要注意规避影响因素,规范操作,就可大大提高维生素B12片鉴别(2)的检验质量,保证检验结果的准确性。     

The nutritional importance and pharmacologic effects of cobalt and vitamin B 12 in man]

Cobalt is an unique trace element for man as it can only reveal its essential properties if provided directly as its biological active form, cobalamin or vitamin B12, the daily requirement of which is 1 to 2 micrograms in adults. This vitamin takes part in the activity of the enzyme methylmalonyl coenzyme A mutase, involved in the conversion of propionyl CoA to succinyl CoA, an intermediary product of the citrate cycle, and of the 5-methyltetrahydrofolate: homocystein methyltransferase, working in the metabolism of methionin and in DNA synthesis. Vitamin B12 deficiency is responsible for a megaloblastic anemia called pernicious anemia and for specific neurological disorders that can be corrected by adequate supplementation. Inorganic cobalt salts can therefore not be considered as essential micronutrients for man, but being able to induce polycythemia, they have a pharmacological property that was recommended in the treatment of various anemias, and they are also used in the management of cyanide poisoning.     

Homocysteine, vitamin B12 and folic acid levels in psoriatic patients and correlation with disease severity

Hyperhomocysteinaemia represents an independent risk factor for atherosclerotic cardiovascular disease, stroke, peripheral arterial occlusive disease and venous thrombosis. Psoriasis is a chronic inflammatory skin disease associated with increased atherothrombosis and cardiovascular risk profile. The aim of this study is to investigate homocysteine, folic acid and vitamin B12 levels in a cohort of psoriatic patients and its relationship with the severity of the disease. A retrospective observational study in 98 patients with chronic plaque psoriasis and 98 healthy controls was performed. Total plasma homocysteine level, folic acid, vitamin B12 and PASI index were assessed in every patient. Patients with psoriasis had plasma homocysteine levels higher than controls (57% of cases and 25% of controls; p<0.0001). Folic acid and vitamin B12 plasma levels were lower in psoriatic patients than in controls (p = NS), lower levels of vitamin B12 were found in patients with hyperhomocysteinaemia compared to patients with a normal value of homocysteine (p = 0.0009). The severity of psoriasis assessed according to PASI (19.51+/-16.26) did not directly correlate either with higher levels of homocysteine or with vitamin B12 and folic acid plasma levels. In conclusion, a significantly higher prevalence of hyperhomocysteinaemia was found in psoriatic patients compared to healthy controls. A significant correlation between hyperhomocysteinaemia and lower vitamin B12 levels, but not folic acid, was evidenced. On the contrary, our data do not correlate the high level of homocysteine with higher PASI scores or psoriasis type, suggesting that homocysteine level can be considered an independent risk factor in psoriatic patients.     

Vitamin B12-induced acneiform eruption

Drug-induced acne is a specific subset of acne that usually has some specific features, namely monomorphic pattern, unusual location of the lesions beyond the seborrheic areas, uncommon age of onset, a resistance to conventional acne treatment. Several drugs have been associated with the development of eruptions that may simulate acne vulgaris. However, so far, there are a few cases of vitamin B12-induced acne. We report a case of acneiform eruption induced by vitamin B12 injection in a 37-year-old female patient.     

Effect of CYP2C19 polymorphism on serum levels of vitamin B12 in patients on long-term omeprazole treatment

BACKGROUND: The S-mephenytoin hydroxylase is a polymorphic cytochrome P450 (CYP) enzyme, identified as CYP2C19, which catalyses the metabolism of omeprazole and some other drugs. AIM: To determine whether long-term treatment with omeprazole affects serum vitamin B12 levels, and if so to what extent it depends on CYP2C19 activity. METHODS: Serum vitamin B12 levels (pmol/L) were assessed in 179 patients. Genotyping for wild-type (wt) and mutated (mut) CYP2C19 alleles was performed by allele-specific PCR amplification. RESULTS: One-hundred and eleven of the patients received one dose of 20 mg omeprazole. No difference in B12 levels were found between heterozygous (wt/mut) (n = 23) and homozygous (wt/wt) (n = 85) patients (mean +/- s.d., 350 +/- 82 vs. 315 +/- 87 pmol/L, respectively). Three patients were mut/mut, with serum vitamin B12 levels of 303 +/- 50 pmol/L. In the 68 patients on long-term (>1 year) therapy with 20 mg omeprazole daily, serum vitamin B12 levels were lower in the heterozygous (wt/mut) (n = 19) compared to homozygous wt/wt (n = 49) (246 +/- 71 vs. 305 +/- 98 pmol/L, P = 0. 01, respectively). In one patient (mut/mut) who was studied both after a single dose and after long-term (15 months) treatment with omeprazole, serum vitamin B12 decreased from 360 to 178 pmol/L. In the wt/mut, but not in the wt/wt group, serum vitamin B12 levels were significantly lower in patients on long-term therapy compared with those receiving one dose (246 +/- 71 vs. 350 +/- 82 pmol/L, P < 0.0001, respectively). CONCLUSIONS: CYP2C19 polymorphism significantly affected serum vitamin B12 levels in patients on long-term therapy with omeprazole. In the future, genotyping of CYP2C19 may be useful for patients in need of long-term treatment with omeprazole or other proton pump inhibitors.     

维生素B12与腔隙性脑梗塞后抑郁的关联研究

目的 探讨血清维生素B12与腔隙性脑梗塞后抑郁之间关系。方法 2009年6月—2012年6月腔隙性脑梗塞患者共829例,使用汉密尔顿抑郁量表将患者分为两组：无抑郁组和抑郁组,比较两组间血清维生素B12浓度和维生素B12缺乏者的比例。在抑郁组内对汉密尔顿抑郁量表评分和血清维生素B12浓度进行曲线拟合。结果 无抑郁组患者750例,血清维生素B12平均浓度为(172.5±20.4)pmol·L^-1,其中维生素B12缺乏者212例。抑郁组79例,血清维生素B12平均浓度为(139.1±18.2)pmol·L^-1,其中维生素B12缺乏者53例。两组间维生素B12浓度和缺乏比例均存在显著差异(P<0.000 1)。通过对汉密尔顿抑郁量表评分随血清维生素B12浓度变化的曲线拟合得知,倒数曲线拟合度较好。结论 腔隙性脑梗塞后抑郁与维生素B12缺乏存在相关性。     

高效液相色谱法测定复方维生素胶囊中维生素B_(12)的含量

目的:建立以高效液相色谱法测定复方维生素胶囊中维生素B12含量的方法。方法:色谱柱为HypersilODS,流动相为甲醇-0.05mol/L磷酸二氢钾缓冲液(22∶78,pH=6.4),流速为1.0ml/min,检测波长为360nm,柱温为室温,进样量为20μl。结果:维生素B12进样量在10.20μg～204.00μg范围内与峰面积积分值线性关系良好(r=0.9999),平均回收率为99.7%(RSD=1.18%)。结论:本方法简便、快速、准确,不受维生素B6、叶酸等成分的干扰,可用于测定复方维生素胶囊中维生素B12的含量。