可溶性转铁蛋白受体在糖尿病患者贫血诊断中的应用

本文探讨了可溶性转铁蛋白受体水平在糖尿病（DM）患者缺铁性贫血（IDA）和非缺铁性贫血鉴别诊断中的意义。     

转铁蛋白受体与磁共振分子影像学研究近况

分子生物学与医学影像学交叉而形成的分子影像学已成为医学研究的热点之一.磁共振分子成像是其中最有前途的技术,其成像的关键在于报告基因系统的选择应用.综述了以转铁蛋白受体为报告基因系统的磁共振成像研究近况.     

妊娠合并再生障碍性贫血行剖宫产手术麻醉处理1例

病人,女,27岁。孕38周入院。10年前确诊为慢性再生障碍性贫血(简称再障)。长期服中药治疗。孕5月时我院查血:WBC 6.47×109/L,RBC 1.83×1012/L,Hb 70 g/L,PLT37×109/L。凝血四项正常,输注4 URBC。贫血好转后出院。孕37周查血:WBC 5.64×109/L,RBC 1.98×1012/L,Hb 72 g/L,PLT26×109/L。凝血四项正常。鉴于患者再障有明显加重的趋势,并有发生自发性出血的可能,建议患者38周时入院观察,必要时终止妊娠。入院查血WBC 5.28×109/L,RBC 1.80×1012/L,Hb 72 g/L,Hct23.2%,PLT17×109/L。凝血四项正常。无自发性出血。入院诊…     

X射线全身照射对小鼠脾细胞转铁蛋白受体表达的影响

目的转铁蛋白受体（ＴｆＲ）是Ｔ淋巴细胞受抗原或丝裂原刺激后表达在细胞表面的重要受体之一,与Ｔ细胞的活化和增殖有着密切关系。目前尚未见国内外有关ＴｆＲ辐射效应研究的报道。研究大剂量电离辐射后ＴｆＲ表达的变化及作用,对阐明辐射抑制机体免疫功能的机制有着重要意义。方法本文采用流式细胞术的方法观察了不同剂量Ｘ射线全身照射对小鼠脾细胞ＴｆＲ表达的影响以及４ＧｙＸ射线全身照射后不同时间ＴｆＲ表达的变化。结果０５～６ＧｙＸ射线全身照射后２４小时,脾脏ＴｆＲ阳性细胞数从１Ｇｙ开始随照射剂量的增加而下降,且呈明显的剂量依赖性。４ＧｙＸ射线全身照射后１２～７２小时,脾脏ＴｆＲ阳性细胞数于照后１２小时开始下降,２４、４８小时降至最低值（Ｐ＜０．０５,Ｐ＜０．０１）,７２小时开始回升。结论大剂量电离辐射抑制小鼠脾细胞ＴｆＲ的表达,并有明显剂量依赖性;ＴｆＲ表达的下降可能与辐射抑制ＩＬ２的分泌和ＩＬ２受体的表达有关。     

血清高浓度转铁蛋白受体与缺铁性贫血的关系

铁能进入红母细胞是通过血浆转铁蛋白和细胞表面的转铁蛋白受体(TfR)相互作用而介导。     

转铁蛋白受体1表达在弗朗西斯菌入侵巨噬细胞中的作用

目的 评估土拉弗朗西斯菌LVS感染鼠巨噬细胞期间获取铁的影响因素.方法 用表达绿色荧光蛋白(GFP)的土拉弗朗西斯菌LVS感染鼠巨噬细胞J774A.1.结合单抗的转铁蛋白受体-1用键合了Alexa594的羊抗鼠二抗显色.用实时定量PCR法检测5个铁代谢相关基凶在土拉弗朗西斯菌LVS感染或未感染J774A.1鼠巨噬细胞中的表达.用活的弗朗西斯菌和灭活菌分别感染巨噬细胞,免疫印迹分析比较Tfr1表达水平.用小十扰RNA下调转铁蛋白受体-1的表达,进而用土拉弗朗西斯菌LVS分别感染转铁蛋白受体-1表达下调的细胞和转染无关siRNA的细胞,并进行细菌计数.结果 土拉弗朗西斯菌疫苗株可以诱导转铁蛋白受体-1在宿主巨噬细胞中表达.基因表达分析显示土拉弗朗西斯菌LVS随着时间的增加通过诱导转铁蛋白受体1(Tfr1)~.节蛋白(Irp1和IRP2)主动获取铁.免疫印迹结果表明小干扰RNA对转铁蛋白受体-1的表达下调了大约75%.细菌入侵试验显示,在感染1h时,转铁蛋白受体-1表达下调的细胞内细菌数量等同于对照(F=1.06,P=0.326 5);而在感染24h时,Tfr1下调样本中的细菌数量明显低于对照样本(F=24.12,P=0.000 6).结论 在感染早期Tfr1的上调是由翻译后调节介导的,并随着Irp1和IRP2表达的增加而增加.Tfr1表达的增加通过转铁蛋白介导的铁运输扩充了细胞内动态铁池,使弗朗西斯菌易于获取铁.转铁蛋白受体-1的下调不影响细菌与其他膜蛋白的结合而入侵,但抑制细菌在细胞内的增殖.     

MCV、MCH及SF在妊娠合并地中海贫血的临床应用

目的：探讨MCV、MCH及血清铁蛋白联合应用在地中海贫血中的诊断意义。方法健康对照组60例,地中海贫血杂合子携带者120例,应用Beckman-Coulter （贝克曼-库尔特） LH750型五分类血细胞分析仪检测红细胞MCV、MCH。用化学发光法测定血清铁蛋白。结果地贫组和IDA组MCV、MCH 均减低,两者与健康对照组比较,差异均有统计学意义（ P＜0.01）。地贫组与IDA组比较,地贫组MCV较IDA组明显减低,两者之间差异有统计学意义（ P＜0.01）。 IDA组SF降低,而地贫组SF不低,两者之间差异有统计学意义（ P＜0.01）。结论（1）MCV、MCH及血清铁蛋白可作为筛查孕妇地贫的有效指标;（2）做好产前地贫的筛查,对预防和降低重型地贫患儿出生具有重要意义。     

微量免疫比浊法测定血清免疫球蛋白、转铁蛋白和载脂蛋白含量

本研究建立了一种微量免疫比浊方法,可同时测定人体血清免疫球蛋白(IgG、IgA、IgM)、转铁蛋白(Tf)和载脂蛋白(Apo-AI,Apo-B).方法原理根据人体蛋白质分子的抗原特性,与抗体试剂发生特异性结合后形成微细颗粒复合物在PEG液中沉淀,经呈90度角的荧光照射后所产生的光散射强度求得相应的蛋白质含量.方法具有用血量微、灵敏度高和简单快速的特点.本文用此方法对我国优秀运动员的正常参考值进行了测定.     

转铁蛋白表面修饰5-Fu白蛋白纳米囊的制备

目的：以血清糖蛋白转铁蛋白为纳米囊的表面修饰剂，对5-Fu白蛋白微囊表面进行修饰，改变纳米囊的靶向特性，提高纳米囊制剂在体现人的靶向效果。方法：以双功能偶联剂戊二醛为偶联剂，用转铁蛋白为5-Fu白蛋白微囊表面进行修饰，用ELISA方法对修饰结果进行检测。结果：白蛋白纳米囊表面进行修饰，修饰量在1mg-10mg范围内成线性关系：Y=1.7112x-0.4452(r=0.95)，所修饰的转铁蛋白保持了其免疫原性（反应原性）。结论：采用文中建立的方法用转铁蛋白对白蛋白纳米囊表面进行修饰，修饰的转铁蛋白保持了其免疫原性，可与细胞表面的转铁蛋白受体结合，提高了纳米囊的主动靶向特性。     

Detection and quantification of protein-losing enteropathy with indium-111 transferrin

Localisation and quantification of protein loss in protein-losing enteropathy (PLE) is useful in the clinical managment of hypoalbuminaemia. Indium-111 transferrin offers the opportunity of combining localisation and quantification using a single agent. Twenty-five studies were performed in 23 patients with suspected PLE:¹¹¹In-transferrin was prepared by incubating autologous cell-free plasma with¹¹¹In chloride in vitro for 15 min. Protein loss was quantified by comparing whole-body counts recorded with an uncollimated gamma camera at 3 h and 5 or 6 days after injection of¹¹¹In-transferrin. Gamma camera imaging performed at 3 and 24 h after injection demonstrated a site of protein loss in 15 studies. Whole-body¹¹¹In excretion was abnormally elevated in 13 of these, ranging from 16% to 34% (normal <10%), was not assessed in one and was less than 10% in a patient with carcinoid syndrome. In the ten studies that were negative on imaging, whole-body¹¹¹In excretion was normal in nine and elevated at 22% in a further patient with carcinoid syndrome. Overall, the mean whole-body¹¹¹In excretion in studies with positive imaging was 21.4% (SD 6.1%) (n=14), significantly higher (P<0.01) than in studies with negative imaging, in which it was 7.5% (SD 6.7%) (n=10). This technique should be useful for the combined approach of localising and quantifying protein loss in PLE.     

Cellular MRI contrast via coexpression of transferrin receptor and ferritin.

Recently there has been growing interest in the development and use of iron-based contrast agents for cellular imaging with MRI. In this study we investigated coexpression of the transferrin receptor and ferritin genes to induce cellular contrast in a biological system. Expression of transgenic human transferrin receptor and human ferritin H-subunit was induced in a stably transfected mouse neural stem cell line. When grown in iron-rich medium, the transgenic cells accumulated significantly more iron than control cells, with a trend toward an increase in reactive oxygen species, but no detrimental effects on cell viability. This cellular iron significantly increased the transverse relaxivities, R2 and R2*, at 1.5 T and 7 T. By comparing measurements in the same cell samples at 1.5 T and 7 T, we confirmed the expected increase in relaxivity with increasing field strength. Finally, supplemented transgenic cells transplanted into mouse brain demonstrated increased contrast with surrounding neural tissue on T2*-weighted MR brain images compared to controls. These results indicate that dual expression of proteins at different critical points in the iron metabolism pathway may improve cellular contrast without compromising cell viability.     

Association of SNPs in transferrin and transferrin receptor genes with blood iron levels in human

Iron is bound to mobile transferrin (TF) and ferritin in blood. TF receptors (TFRC and TFR2) regulate intracellular iron by delivering iron from TF into the cytoplasm. In this study, we examined the effects of 10 single nucleotide polymorphisms (SNPs) in each of the genes for TF and TF receptors on blood iron concentrations in Japanese subjects. Blood iron levels were determined by microwave plasma-atomic emission spectrometry and the SNPs were analyzed by polymerase chain reaction followed by restriction fragment length polymorphism analysis. Blood iron levels in males were significantly higher than those in females. Therefore, the analysis was performed only in males. Blood iron concentrations did not correlate with age and postmortem intervals in males. Among the 10 SNPs in TF, TFRC, and TFR2 genes, significant associations were observed between TF genotypes (rs12769) and male iron concentrations. Individuals with genotype GG in rs12769 had significantly higher blood iron concentrations than those with GA. Previous studies have shown the association between high tissue iron concentrations and disease, liver iron levels are higher in infants dying from sudden infant death syndrome and decreased blood iron concentrations were observed in critically ill children. Therefore, rs12769 in TF might be related to diseases and mortality risk.     

Comparative response of EPO and soluble transferrin receptor at high altitude

PURPOSE: Soluble transferrin receptor (sTfR) classically raises with increased erythropoiesis, along with the rise in erythropoietin (EPO). However, the specific effect of altitude-induced erythropoiesis on sTfR remains poorly documented. This study investigated the response of sTfR during high-altitude exposure in human and verified that sTfR was related to EPO response in this case. METHODS: EPO, sTfR, red cell volume (RCV), ferritin, and iron intake were measured during: 1) experiment A (N = 8, 31 d at 5000-8848 m), at sea level (SL), and at the simulated altitude of 5000, 6000, 7000, and 8000 m; and 2) during experiment B (N = 10, 7 d at 4350 m), at SL, after 3, 5, and 7 d at 4350 m and 1-2 d after return to SL (RSL). RESULTS: In experiment A, progressive decompression from SL to 8000 m induced a large parallel rise in EPO (33.8-fold) and sTfR (5.9-fold), whereas ferritin was dramatically decreased and iron intake reduced. RCV was increased after 31 d of decompression. In experiment B, EPO peaked at day 3 at 4350 m, then declined later at altitude and returned to baseline values at RSL, whereas sTfR progressively rose at altitude (+86%) and remained elevated during RSL (+64%). Ferritin progressively declined at 4350 m, whereas iron intake was unchanged. RCV was not enhanced after exposure to 4350 m. CONCLUSION: In summary, sTfR mirrors EPO response for a given level of altitude hypoxia but differs from EPO response during transitory phases, such as early acclimatization or reoxygenation. Analysis of sTfR may therefore account for altitude-related erythropoiesis, at a time when EPO is blunted.     

Prevalence of hepatosplenomegaly in beta thalassemia minor subjects in Iran

Introduction

Thalassemia is the most common hereditary blood disorder in the world. Iran is located on the thalassemic belt and there is a high prevalence of the hepatosplenomegaly in beta thalassemia minor patients which is reported to be very variable. The goal of this research was to study the frequency of these signs in the cases with beta thalassemia minor patients in Iran.

Materials and methods

Two hundred and fifty-nine cases that referred to center for pre-marriage tests were divided into two groups according to their MCV, MCH, and HbA2 (beta thalassemia minor cases and control groups). Liver and spleen sizes were determined by ultrasonographic method and the two groups were compared with each other.

Results

Average spleen volumes in case and control groups were 163.48 ± 133.97 and 126.29 ± 53.98 mm³, respectively. Average spleen lengths in case and control groups were 10.71 ± 1.52 and 10.60 ± 5.4 cm, respectively.

Conclusion

In the regions with high frequency of beta thalassemia, in case of finding large spleen size in the ultrasonography, a probable harmless differential diagnosis will be beta thalassemia minor that is not indicative of any serious disease.Volumetric measurement of spleen is more reliable for detection of splenomegaly in these patients.     

Effects of exercise on soluble transferrin receptor and other variables of the iron status

BACKGROUND: Soluble transferrin receptor (sTfr) is a new marker of iron status and erythropoietic activity. It has been included in multivariable blood testing models for the detection of performance enhancing erythropoietin misuse in sport. OBJECTIVE: To evaluate the effect of different types and volumes of physical activity on sTfr concentration, variables of iron status (ferritin, transferrin, iron, and protein), and haematological indices. METHODS: Thirty nine subjects were divided into three groups: 1, untrained (n = 12); 2, moderately trained (n = 14); 3, highly trained (n = 13, seven men, six women). Groups 1 and 2 carried out two exercise tests: an incremental running test until exhaustion (test A) and a 45 minute constant speed running test at 70% VO(2)MAX (test B). Group 3 performed three days (women) or four days (men) of prolonged aerobic cycling exercise. The above variables together with haemoglobin and packed cell volume were analysed in venous blood samples before and after exercise. Changes in blood and plasma volume were estimated. RESULTS: sTfr levels were slightly increased in trained and untrained subjects immediately after test A. Test B and aerobic exercise had no significant effect on sTfr. Ferritin levels were increased after the laboratory tests for trained and untrained subjects and after prolonged aerobic exercise in male cyclists. Transferrin was increased significantly in trained and untrained subjects after both laboratory tests, but remained unchanged after prolonged exercise. Plasma and blood volumes were decreased after the laboratory tests but increased after aerobic exercise. No differences in the variables were observed between trained and untrained subjects with respect to response to exercise. CONCLUSION: The changes in sTfr and the variables of iron status can be mainly attributed to exercise induced changes in volume. Taking these limitations into account, sTfr can be recommended as a marker of iron deficiency in athletes.     

Widespread marrow necrosis during pregnancy

Recently, a 22-year-old Caucasian female was referred to our Hospital two days post-partum. She had been feeling unwell during the last few days of her pregnancy and complained of multiple aches and pains, worst in the abdomen and lower back. Her admission platelet count was severely depressed and a bone biopsy showed extensive marrow necrosis with viable bony trabeculae. There was no evidence of vasculitis, vascular thrombosis, or malignancy. Widespread marrow necrosis in pregnancy followed by recovery, to our knowledge, has not been previously reported.Presented by Dr. W. James Knickerbocker at the 7 th Annual Meeting of the International Skeletal Society in Mexico City, Mexico, August 26–31, 1980