Muscle weakness in intensive care patients: Initial manifestation of vitamin D deficiency

A 72-year-old woman was referred to hospital for obnubilation with general muscle weakness and hypotonia. Biology showed hypocalcemia, hypophosphatemia, increased serum creatine kinase and alkaline phosphatase levels. Brain CT scan, cerebrospinal fluid examination, and electromyogram were normal. Clinical status and electroencephalogram were consistent with non-convulsive generalized status epilepticus. The treatment included clonazepam and CaCl₂ and consciousness returned to normal. A treatment with multivitamin infusion containing vitamin D₂ was given for 3 weeks. Muscle weakness improved partially. Serum vitamin D₃ level was low and osteomalacic myopathy was diagnosed. A treatment was given with 25OH vitamin D₃, 50 g per day. Two months later, serum vitamin D₃ and creatine kinase levels were normal and the patient could walk without help. We conclude that vitamin D status should be monitored in elderly patients with muscle symptoms and abnormal calcium status. Osteomalacic myopathy should be considered in critically ill patients with muscle symptoms of an unclear cause.     

22-ene-25-oxa-vitamin D: a new vitamin D analogue with profound immunosuppressive capacities

BACKGROUND: The biologic role of 1,25-dihydroxyvitamin D(3), such as anti-inflammatory functions, reduction of cytokine production by T cells and immunoglobulin production by B cells, is well established. However, its clinical use as an immunosuppressive agent is limited because of the hypercalcemic toxicity occurring after systemic application. The purpose of this study was to investigate the immunmodulatory effects of 22-ene-25-oxa-vitamin D (ZK156979), a novel low calcemic vitamin D analogue. MATERIALS AND METHODS: Human peripheral blood mononuclear cells (PBMCs) from healthy donors were isolated using the Ficoll Hypaque technique, cultured for 24 h and treated with different concentrations of ZK156979 ranging from 10(-5) to 10(-10) mol L(-1) compared with 1,25-dihydroxyvitamin D(3)[10(-5)-10(-10) mol L(-1)] following phytohaemagglutinin (PHA) stimulation. Interferon gamma (IFNgamma), tumour necrosis factor alpha (TNFalpha), interleukin 1 beta (IL-1beta), interleukin 10 (IL-10) and interleukin 4 (IL-4) secretion in supernatants were measured by ELISA. RESULTS: ZK156979 inhibited the PHA-induced Th1-response (IFNgamma and TNFalpha levels) and the macrophage-product IL-1beta in a concentration-dependent manner (10(-10)-10(-5) mol L(-1)) with the efficiency on cytokine expression compared with 1,25-dihydroxyvitamin D(3) being slightly reduced. In contrast, ZK156979 and 1,25-dihydroxyvitamin D(3) both affected the Th2 response, leading to significantly increased IL-10- and IL-4 secretion. CONCLUSIONS: ZK156979 is a member of novel vitamin D analogues revealing prominent immunomodulatory and suppressive characteristics with distinctive inhibition of Th1-cytokines whereas the Th2 compartment is augmented, thus providing a considerable therapeutic potential in T-cell -mediated diseases.     

Transport of vitamin D sterols in human plasma: effect of excess vitamin D, 25 hydroxyvitamin D and 1,25 dihydroxyvitamin D

Abstract. Vitamin D and its more active metabolites, 25 hydroxyvitamin D (25-OH-D) and 1,25-dihydroxy-vitamin D (1,25-(OH)₂-D), are transported in human plasma on a specific binding protein (DBP), which has been shown to have an α-globulin electrophoretic mobility. Since the concentration of DBP in normal human plasma is approximately 5 μmol/l, whereas that of all the vitamin D metabolites is less than 0·2 μmol/l, DBP is less than 3% saturated under physiological conditions. We have studied the transport of the above-mentioned metabolites in human plasma in vitro at normal and saturating concentrations. Human plasma was incubated with increasing amounts of vitamin D metabolites together with their radiolabelled tracers. Ultracentrifugation was used to isolate plasma lipoproteins (density, d < 1·21 g/ml) and agarose gel electrophoresis of lipoprotein-free plasma (d > 1·21 g/ml) to separate DBP (α globulin) from albumin. The recovery of the tracer in plasma proteins was always more than 80%. At physiological concentrations [³H]25-OH-D bound almost exclusively to DBP (98%), [³H]vitamin D or [¹⁴C]vitamin D bound both to DBP and to lipoproteins (40%), and [³H]1,25-(OH)₂-D bound to DBP (62%), to lipoproteins (15%) and also to albumin (23%). When the concentration of vitamin D metabolites was increased, DBP became saturated. The binding capacity of DBP was similar for all three sterols, about 5 μmol/l plasma, or one mole of sterol per mole of protein, but the saturating concentration was different for the three sterols (vitamin D > 1,25-(OH)₂-D > 25-OH-D). 25-OH-D had the greatest affinity for DBP, and it completely displaced both vitamin D and 1,25(OH)₂-D from DBP at higher concentrations. All sterols bound to both plasma lipoproteins and albumin: vitamin D preferentially to lipoproteins and both 25-OH-D and 1,25-(OH)₂-D to albumin. A similar binding pattern for vitamin D in plasma was observed previously by us in a child with vitamin D toxicity. The increased binding of vitamin D to lipoproteins and especially to albumin may help explain the pathogenesis of toxicity in hypervitaminosis D, where the plasma levels of the more active metabolites are insufficient to account for the clinical signs.     

哮喘儿童血清1,25-二羟维生素D_3表达水平变化及其意义

目的探讨血清1,25-二羟维生素D3水平测定在儿童支气管哮喘治疗及预后的价值。方法采用酶联免疫吸附法(ELISA)分别测定142例不同严重程度哮喘患儿血清1,25-(OH)2D3值(分为轻、中、重3组),同时测定80例正常儿童血清1,25-(OH)2D3值。以上哮喘儿童经跟踪治疗1个月后,病情控制期时再测定以上指标,评价不同病程中受试儿童1,25-(OH)2D3水平变化的差异。结果重度组患儿血清1,25-(OH)2D3水平最低,正常儿童血清1,25-(OH)2D3水平最高,正常儿童及不同严重程度哮喘患儿血清1,25-(OH)2D3值差异均具有显著性(P0.05)。142例患儿进入病情控制期后,不同控制情况患儿血清1,25-(OH)2D3水平差异显著(P0.05),其中完全控制组血清1,25-(OH)2D3水平明显高于部分控制组及未控制组。结论哮喘儿童血清1,25-(OH)2D3处于低水平状态并与其病情严重程度及控制情况有关。因此,儿童哮喘血清1,25-二羟维生素D3表达水平的监测对预测病情程度、评价预后均有一定意义。     

1,25-二羟维生素D3对IgA肾病大鼠白介素-4的调节作用

目的 探讨1,25-二羟维生素D3对IgA肾病大鼠白介素-4的调节作用. 方法 52只Wister大鼠剔除死亡随机分为A组（正常对照组）、B组（未干预组）、C组（强的松组）、D组（1,25 （OH）-2D3组）、E组（强的松＋1,25 （OH）-2D3组）.检测大鼠24小时尿蛋白定量、脾脏及淋巴结IL-4含量. 结果 ①尿蛋白定量：A组（正常对照组）为7.03±0.99 mg/24h;B组（未干预组）为51.49±3.04 mg/24h;C组（强的松组）为12.15±0.75 mg/24h;D组（1,25 （OH）2D3治疗组）为23.0±2.27 mg/24h;E组（强的松＋1,25 （OH） 2D3治疗组）为9.99±0.79 mg/24h;经治疗后C、D、E组24h尿蛋白较B组均有显著下降（P＜0.05）,其中E组下降最显著（P＜0.05）;②脾脏IL-4含量：A组（正常对照组）1.428±0.60％;B组（未干预组）5.10±0.08％;C组（强的松组）2.93±0.13％;D组（1,25 （OH） 2D3治疗组）4.56±0.19％;E组（强的松＋1,25 （OH） 2D3治疗组）1.44±0.56％;③淋巴结IL-4含量：A组（正常对照组）1.50±0.13％;B组（模型组）15.4±3.11％;C组（强的松组）2.74±0.29％;D组（1,25 （OH） 2D3治疗组）6.55±0.66％;E组（强的松＋1,25 （OH）2D3治疗组）2.32±0.34％.C、D、E组脾脏及淋巴结IL-4含量较B组均有显著下降（P＜0.05）,其中E组下降最显著（P＜0.05）. 结论 1,25-二羟维生素D3可能下调IgA肾病大鼠IL-4的表达,影响Th2细胞的调节.     

Analytical and clinical validation of a radioimmunoassay for the measurement of 1,25 dihydroxy vitamin D

OBJECTIVES: The analytical and clinical validation of the DiaSorin 1,25 dihydroxyvitamin D RIA is described. DESIGN AND METHODS: The analytical parameters assessed included analytical sensitivity, dilution linearity, intra- and inter-assay precision, recovery, specificity, and interference studies. Where appropriate, assessments were performed according to NCCLS guidelines. The clinical validation assessed normal individuals and end-stage renal disease patients. RESULTS: The analytical sensitivity of the assay is < 2.0 pg/mL or < 4.8 pM. The assay is specific for both 1,25 dihydroxyvitamin D2 and D3. Recovery ranged from 97% to 108% for spiked samples. Intra-assay precision, as %CV, ranged from 7% to 11%, while inter-assay precision was 12% to 15%. No interference was observed from bilirubin, cholesterol, hemoglobin, or triglycerides. Clinical validation demonstrated complete discrimination between normal and ESRD populations. CONCLUSIONS: These data demonstrate that the DiaSorin 1,25 (OH)(2) vitamin D RIA is a robust, accurate, and precise tool for the assessment of 1,25 (OH)(2) vitamin D.     

1,25（OH）2维生素D3对人树突状细胞成熟及其介导免疫耐受的影响

本研究旨在探讨1,25(OH)2维生素D3〔1,25(OH)2Vit D3〕对人树突状细胞(DC)分化、成熟及功能的影响及其机制。在体外将人外周血单个核细胞诱导分化成DC,实验组加入1,25(OH)2Vit D31 nmol/L培养9 d,对照组加入等量无水乙醇,流式细胞仪检测DC表面共刺激因子表达水平。混合淋巴细胞培养后,用MTT法评估DC刺激同种异体T细胞增殖的能力。Western blot检测DC吲哚胺2,3-双加氧酶(IDO)蛋白表达。结果表明,与对照组相比,实验组DC表面标志CD80、CD83、CD86表达率低于对照组(P<0.05),CD1a高于对照组(P<0.05);CD80、CD83、CD86、CD1a表达率分别为(40.43±9.83)%、(20.04±4.73)%、(14.45±5.38)%,(58.48±10.72)%;对照组CD80、CD83、CD86、CD1a表达率分别为(29.36±13.34)%、(35.91±10.19)%、(27.15±11.64)、(72.20±12.79)%。实验组DC刺激同种异体T细胞增殖的能力受到抑制;DC表达IDO蛋白上调。结论:1,25(OH)2Vit D3抑制DC的成熟,通过上调DC的IDO蛋白表达抑制DC刺激同种异体T淋巴细胞增殖及介导免疫耐受。     

急性肾损伤危重患者血清1,25二羟维生素D水平对其预后的影响

目的观察血清1,25二羟维生素D[1,25(OH)_2D]水平与急性肾损伤(AKI)危重患者预后的相关性。方法回顾性分析2014年12月至2015年12月入住上海交通大学附属第六人民医院45例AKI患者的临床资料,按预后结果分为存活组和死亡组。检测患者血清1,25(OH)_2D、甲状旁腺激素、25-OH维生素D、钙和磷等对预后的影响。结果 45例患者中10例住院死亡,病死率为22.2%。存活组与死亡组AKI患者的血清1,25(OH)_2D水平间差异有统计学意义[(63.2±41.5)pg/mL vs.(33.8±24.1)pg/mL,P=0.043];死亡组患者血清磷水平高于存活组,且差异有统计学意义[(6.3±2.1)mg/dL vs.(4.5±1.6)mg/dL,P=0.019]。多因素Logistic回归分析显示,高急性生理与慢性健康评分(APACHEⅡ评分)以及高水平1,25(OH)_2D为AKI患者预后的危险因素(OR=1.191,95%CI:1.154~1.233,P=0.008;OR=1.281,95%CI:1.067~1.538,P=0.018)。结论1,25(OH)_2D与AKI患者死亡具有相关性,临床上可作为判断AKI患者预后的指标。     

维生素D及其受体在强直性脊柱炎患者中的表达及其临床意义

目的：研究As患者PBMC维生素D受体（VDR）mRNA的表达及血清25-羟维生素D,和1,25-二羟维生素D3的水平,探讨其与AS疾病活动性（BASDAI、CRP、ESR）的相关性。方法：选取26例AS患者（As组）和年龄、性别与之相匹配的13名健康志愿者（健康对照组）。采用SYBRGreenI实时荧光定量PCR检测两组受检者PBMC的VDRmRNA表达水平,应用ELISA法检测两组受检者血清25-羟维生素D3和1,25-二羟维生素D3水平,分析VDRmRNA表达水平、血清25-羟维生素D3和1,25-二羟维生素D3水平与临床相关指标（BASDAI、CRP、ESR）的关系。结果：As患者PBMC的VDRmRNA表达水平明显高于健康对照组（P〈0．01）,VDRmRNA表达水平与临床相关指标（BASDAI、CRP、ESR）无关（P〉0．05）。AS患者血清25．羟维生素D3、1,25-二羟维生素D3水平分别为（5．3±2．6）μg／L、（12．8±6．0）ng／L,明显低于健康对照组（14．7±3．5）μg/L、（32．6±18．5）ng／L（P均〈0．01）。AS患者血清1,25-二羟维生素D3的水平与BASDAI（r=-0．481,P〈0．05）、ESR（r=-0．535,P〈0．01）、CRP（r=-0．674,P〈0．01）均呈负相关。血清25-羟维生素D,水平与BASDAI、CRP、ESR无关（P〉0．05）。结论：As患者VDRmRNA表达水平升高,但与As的疾病活动无关。As患者血清1,25-二羟维生素D3水平下降,与疾病活动呈负相关,可作为AS疾病活动的指标之一。AS患者PBMC的VDR活化可能与1,25-二羟维生素D,的作用无关。     

妊娠糖尿病患者的维生素D受体基因单核苷酸多态性研究

目的探讨维生素D受体基因单核苷酸多态性与妊娠糖尿病(GDM)发病的关系。方法按病例-对照设计的方法,选取GDM患者和健康妊娠对照各80例作为受试对象,采用全自动生化分析仪检测受试者体内血糖和肝功能等指标;应用聚合酶链反应-基因测序法对所有受试者维生素D受体基因上的rs1544410位点进行多态性分析。使用SPSS13.0进行t检验和χ2检验分析。结果两组人群的维生素D受体基因rs1544410的G/A等位基因频率比较差异有统计学意义(P<0.05)。Bb型基因型的空腹血糖水平高于bb型(P<0.05),两组的肝功能指标相比差异无统计学意义。结论维生素D受体基因rs1544410多态性位点与南京地区汉族妊娠糖尿病具有相关性。     

Progress of liquid chromatography-mass spectrometry in measurement of vitamin D metabolites and analogues

Objective

Clinical testing for vitamin D nutritional status has experienced tremendous growth in the past several years, driven by research results linking various diseases with low serum 25-hydroxyvitamin D [25(OH)D] levels. Meanwhile, interest in the pathophysiological mechanism elucidation and pharmaceutical applications requires measurement of vitamin D metabolites and analogues. Liquid chromatography-mass spectrometry (LC-MS) has been increasingly utilized in these applications. In this work, our objective was to critically review the progress of LC-MS application in measuring vitamin D metabolites and analogues in biological fluids.

Methods

The LC-MS methods included were selected from those searchable in PubMed up to January 2010.

Results and Conclusion

LC-MS has unique advantages in measuring various vitamin D metabolites and analogues due to its flexibility, sensitivity, and specificity. Despite some controversies over serum 25(OH)D tests, LC-MS will be used for standardizing serum 25(OH)D assays using reference materials available from the National Institute of Standards and Technology.     

良性原发性甲状旁腺功能亢进症患者血清1,25-二羟基维生素D3水平变化

目的探讨良性原发性甲状旁腺功能亢进症(primary hyperparathyproidism,PHPT)患者血清1,25-二羟基维生素D3[1,25-dihydroxyvitamin D3,1,25(OH)2D3]水平变化及与甲状旁腺激素(parathyroid hormone,PTH)、血钙、血磷的关系。方法良性PHPT患者56例为观察组,同期体检健康者1118例为对照组,采用电化学发光法检测2组血清1,25(OH)2D3、PTH水平,比色法测定血钙水平,磷钼酸盐法测定血磷水平。比较2组维生素D缺乏[1,25(OH)2D3<20μg/L]、严重缺乏[1,25(OH)2D3<10μg/L]的比率及不同年龄分层患者血清1,25(OH)2D3水平变化,Pearson法分析观察组维生素D缺乏、严重缺乏患者血清1,25(OH)2D3与PTH、血钙及血磷的相关性。结果观察组维生素D缺乏比率、严重缺乏比率(94.64%、46.43%)高于对照组(62.79%、14.13%)(P<0.05);Pearson相关分析显示,观察组血清1,25(OH)2D3与PTH、血钙及血磷均无线性相关性(r=-0.226,P=0.352;r=-0.274,P=0.256;r=0.073,P=0.593)。观察组年龄18~40岁、>40~60岁、>60岁患者血清1,25(OH)2D3[(10.76±3.17)、(10.61±5.01)、(10.72±4.85)μg/L]低于对照组[18~40岁:(18.19±9.86)μg/L,>40~60岁:(17.18±9.19)μg/L,>60岁:(17.91±10.52)μg/L](P<0.05);观察组维生素D缺乏患者血清PTH[(818.86±233.49)ng/L]、血钙[(2.98±0.59)mmol/L]、血磷[(0.78±0.17)mmol/L]与维生素D严重缺乏患者[(640.09±622.69)ng/L、(2.96±0.69)mmol/L、(0.75±0.20)mmol/L]比较差异无统计学意义(P>0.05);观察组维生素D缺乏、严重缺乏患者血清1,25(OH)2D3与PTH(r=-0.360,P=0.060;r=0.071,P=0.723)、血钙(r=-0.225,P=0.250;r=-0.228,P=0.252)、及血磷(r=0.239,P=0.221;r=-0.208,P=0.297)均无线性相关。结论良性PHPT患者血清1,25(OH)2D3低于正常人群,维生素D缺乏比率较高,且血清1,25(OH)2D3与PTH、血钙及.血磷无线性相关。     

糖尿病肾病患者血清1，25-二羟维生素D3水平及临床意义

目的探讨血清1,25-二羟维生素D。水平在糖尿病肾病（diabeticnephropathy,DN）进展中的作用。方法131例2型糖尿病患者分为单纯糖尿病组（DM组）30例、早期DN组（EDN组）32例、临床DN组（CDN组）35例与DN终末期组（ESDN组）34例,选择体检健康者30例为对照组,各组采用ELISA法检测血清1,25-二羟维生素D3和25-羟维生素D。水平。结果糖尿病及DN各组血清1,25-二羟维生素D3及25-羟维生素D。水平均明显低于对照组（P〈0．01）,且随DN逐渐进展二者水平均逐渐降低（P〈0．05）;糖尿病患者血清1,25-二羟维生素D3水平与尿微量白蛋白排泄率呈负相关（r=0．452,P=0．034）,与肾小球滤过率呈正相关（r=0．390,P=0．006）。结论血清1,25-二羟维生素D3水平检测可能有利于DN的早期发现和病情判断。     

维生素D水平与2型糖尿病患者血糖控制关系的分析

目的分析维生素D缺乏与2型糖尿病患者的血糖控制及相关炎症因子之间的关系。方法选择110例2型糖尿病患者,按糖化血红蛋白(Hb A1c)水平分为A组和B组,同期选择40名健康体检者。计算BMI,检测空腹血糖(FBG)、餐后2 h血糖、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、超敏C反应蛋白(hs-CRP)、Hb A1c、血清25(OH)D和游离脂肪酸(FFA)等指标。结果 2型糖尿病患者的25(OH)D水平低于正常人(P<0.01),A组的25(OH)D水平低于B组(P<0.05)。血清25(OH)D浓度与BMI、Hb A1c、hs-CRP、FFA呈负相关(P<0.05或P<0.01),与HDL-C呈正相关(P<0.05),与空腹血糖、餐后2 h血糖、LDL-C、TG无明显相关性。结论 2型糖尿病患者维生素D水平普遍低于正常人,且血糖控制越差,BMI越高,这种差异越明显。维生素D与炎症因子h-CRP、FFA呈负相关,这可能是维生素D参与糖尿病发生发展的机制之一。     

维生素D对脂多糖致急性肺损伤大鼠肺组织血管紧张素转化酶2和维生素D受体表达水平的影响

目的 观察维生素D(vitamin D,Vit D)对脂多糖(lipopolysaccharide,LPS)致Wistar大鼠急性肺损伤(acute lung injury,ALI)肺组织中血管紧张素转化酶2(angiotensinconverting enzyme 2,ACE2)和维生素D受体(vitamin D receptor,VDR)表达水平的影响.方法 采用尾静脉注射LPS方法制备大鼠ALI模型;将30只健康雄性Wistar大鼠随机(随机数字法)分为6组:正常对照组(NC组)、LPS组:尾静脉注射LPS 5mg/kg、Vit D组:给予Vit D活性形式(骨化三醇)25 μg/kg连续灌胃3d和(LPS+ Vit D) 1-3组:分别于骨化三醇1μg/kg、5μg/kg、25 μg/kg灌胃3d后尾静脉注射LPS 5mg/kg,所有大鼠于注射LPS的24 h后进行后续实验.分别观察大鼠一般情况,肺组织病理及肺干/湿重比变化、肺组织中VDR、ACE2蛋白及基因水平的表达.结果 LPS组大鼠病态表现(呼吸浅快、精神萎靡、口鼻可见血性分泌物)明显,(LPS+ VitD) 1-3组病态表现和肺组织病理损伤均较LPS组明显减轻.LPS组VDR和ACE2蛋白及基因水平的表达均较NC组和Vit D组显著降低(P＜0.05),(LPS+ VitD) 1-3组各组VDR和ACE2蛋白及基因水平的表达均较LPS组有所升高(P＜0.05),但仍显著低于Vit D组(P＜0.05),其中(LPS+ Vit D) 1-3组各组VDR蛋白及基因水平的表达差异无统计学意义(P＞0.05),ACE2的表达差异有统计学意义(P＜0.05).结论 Vit D能使LPS致ALI大鼠肺组织中ACE2和VDR蛋白及基因表达水平增加,故此推测ACE2和VDR表达增加可能对ALI的发生、发展起保护作用.     

The metabolism of a physiological dose of radioactive cholecalciferol (vitamin D3) to its hydroxylated metabolites in man

1. The metabolism of an intravenous pulse-dose of 65 nmol (25 microgram) of double-isotope-labelled cholecalciferol has been studied in 28 individuals. The subjects comprised 19 with serum concentrations of 25-hydroxycalciferol (25-(OH)D) less than or equal to 25 nmol/l, of whom 12 had clinical osteomalacia, and nine with serum 25-(OH)D > 25 nmol/l (30-125 nmol/l). 2. The concentrations in serum of radioactive cholecalciferol, 25-hydroxycholecalciferol (25-(OH)D3) and the three dihydroxylated metabolites: 1,25-, 24,25- and 25,26-dihydroxycholecalciferol (1,25-(OH)2D3, 24,25-(OH)2D3 and 25,26-(OH)2D3) were measured for up to 10 days after the injection. 3. The temporal relationships between the formation of individual radioactive metabolites and factors apparently influencing their production are described and their molar concentrations in serum calculated. 4. Formation of radioactive 1,25-(OH)2D3 was detectable only in vitamin D-deficient subjects. Between individuals, its maximum serum concentration was correlated significantly and inversely with serum calcium but with not other measured variable. In the individual, concentrations of radioactive serum 1,25-(OH)2D3 varied directly with radioactive serum 25-(OH)D3. 5. The failure to detect formation of radioactive 1,25-(OH)2D3 in vitamin D-replete subjects suggests that current estimates of the daily turnover of the hormone in the normal individual may be severalfold too high. 6. Radioactive 25,26-(OH)2D3 was produced rapidly by all subjects and in greater amounts by vitamin D-deficient individuals. Between subjects and in the individual its concentration in serum correlated only with the radioactive serum 25-(OH)D3. Production of this metabolite appeared to be unregulated and dependent solely on the concentration of its precursor. 7. In vitamin D-replete subjects, production of 24,25-(OH)2D3 was also apparently determined by precursor concentration. In vitamin D-depleted subjects, production of radioactive 24,25-(OH)2D3 was variably delayed for up to or more than 10 days. 8. There appeared to be a constraint on the quantitative hepatic production of 25-(OH)D which is not explained by simple feed-back inhibition. 9. If sterols other than 1,25-(OH)2D3 are required to initiate the mineralization of osteomalacic bone, after correction of vitamin D deficiency in man, 25-(OH)D3 and 25,26-(OH)2D3 are produced sufficiently rapidly to meet this hypothetical requirement, but not 24,25-(OH)2D3.     

25-羟维生素D水平与早期类风湿性关节炎的相关性研究

目的探讨25-羟维生素D浓度与早期类风湿性关节炎的相关性。方法收集东阳市人民医院2009年1～7月类风湿性关节炎患者126例,记录肿胀关节数、压痛关节数、骨侵蚀度等临床指标,并测定25-羟维生素D浓度,分析维生素D水平与患者临床指标的变化,并测定健康对照组40例25-羟维生素D浓度。结果类风湿性关节炎患者25-羟维生素D浓度为(21.3±4.8)ng/mL,健康对照者25-羟维生素D浓度为(37.2±8.6)ng/mL,类风湿性关节炎患者25-羟维生素D浓度低于健康对照者,差异有统计学意义(P0.05),25-羟维生素D浓度与类风湿性关节炎疾病严重程度密切相关,差异有统计学意义(P0.05)。结论外周血25-羟维生素D水平与类风湿性关节炎密切相关,但其作用机制有待深入研究。