造血干细胞的竞争性分化在照后白细胞减少中的作用

LACA小鼠经5 Gyγ线全身照射后l～4天腹腔注射经分离,洗涤和浓集的红细胞(供血鼠预先照射8.5Gyγ线)。其血红蛋白含量上升到正常对照的140.4%。照后20天骨髓CFU-E含量比照射对照组低4倍。虽然其红系造血受到明显抑制,但其骨髓CFU-S,CFU-GM及外周血粒细胞数分别比照射对照组高28、80.3和97.6‰。结果表明,小鼠受照后,存在造血干细胞的竞争性分化,向红系统分化占优势。多血通过反馈机制改变了干细胞的分化方向,使之多向粒系统分化.从而增加了外周血粒细胞数置。本文报告的结果表明照后造血干细胞的竞争性分化及向红系分化占优势是外周血白细胞数量减少的原因之一。     

照射骨髓基质细胞对辐射损伤小鼠造血重建的影响

采用辐照方法将骨髓基质细胞(BMSC)预先强化,再经体外培养、富集后与骨髓细胞(BMC)一起经尾静脉输注给全身致死剂量照射的小鼠。采用股骨BMC计数,CFU-GM和CFU-S测定及股骨切片组织学观察等方法研究了这种细胞对辐射损伤小鼠造血重建的影响。结果表明输入的BMSC对辐射损伤小鼠造血重建具有促进作用。进一步研究表明,这种细胞对辐射损伤小鼠造血重建的促进作用不是由于其中含有造血干细胞(HSC)所致,而是通过其经血循环迁徒至造血组织后对同时输入BMC中的HSC增殖和向粒系分化发挥支持和刺激作用来实现的。     

内源性再生法测定骨髓干细胞的释放

血中含有少许造血干细胞,主要来源于骨髓。虽然其归宿尚不完全清楚,已知其在机体造血需要或造血紊乱的代偿反应中,确实起重要作用。血中干细胞含量可受很多因素影响,如内毒素或皮质激素等药剂,脾或肾上腺切除等机体非正常状态时均可使血中干细胞数量发生改变。为了阐明造血干细胞的迁徒动力学规律,作者观察了干细胞从屏蔽肢向照射脾的迁徙数量,并对其在血流中的正常周转率进行了估算。     

重组人骨形成蛋白-2在造血损伤治疗中作用机制的探讨

目的 探讨重组人骨形成蛋白-2(rhBMP-2)在治疗造血损伤中的作用机制,构建探针并通过原位杂交技术观察rhBMP-2治疗小鼠急性造血损伤的作用。方法 将22只BALB/c雌性小鼠随机分为照射组和骨形成蛋白治疗组。把正常雄性小鼠的骨髓细胞移植给接受8.5 Gy ⁶⁰Coγ 射线照射的22只BALB/c雌性小鼠。14 d后,剩余存活的雌性小鼠左股骨再接受9 Gy的电子线照射。骨形成蛋白治疗组小鼠每天每只腹腔注射重组人骨形成蛋白-2 20 mg/kg,连续治疗6 d,照射对照组每天每只腹腔注射等量生理盐水。14 d后,处死小鼠并取股骨制成石蜡切片。用原位杂交技术检测雌性小鼠股骨中雄性供体小鼠的骨髓细胞。结果 原位杂交结果显示,照射组小鼠左股骨骨髓中的供体来源细胞数量明显比骨形成蛋白治疗组小鼠左股骨骨髓中多(T=155.0,P<0.05)。而照射组小鼠左股骨骨髓中供体来源细胞数量与2组小鼠右股骨骨髓中相比则无明显差异(T=92.0、78.5,P>0.05)。骨形成蛋白组小鼠左股骨骨髓中的供体来源细胞数量明显比两组小鼠右股骨骨髓中少(T=155.0、55.0,P<0.05)。结论 rhBMP-2促进了自身受损伤的骨髓细胞修复,故在骨形成蛋白组小鼠的左股骨骨髓中几乎检测不到供体雄性小鼠SRY基因的存在。推测rhBMP-2促进了自身骨髓间充质干细胞增殖或分化,并改善造血微环境,加快造血修复、重建的过程。     

骨髓基质成纤维样祖细胞的辐射敏感性和照射后的变化

造血组织照射后的变化首先是由于造血细胞损伤引起的,但这些变化也发生在维持造血细胞增殖和分化的造血基质中。局部受大剂量照射后,继发的骨髓     

造血干细胞辐射敏感性的比较

本文研究了在体内外照射条件下小鼠骨髓多向性造血干细胞(CFU-S)和粒系定向干细胞(CFU-C)的辐射敏感性。它们的D(?)值分别为103.4拉德和173.7拉德,反映了CFU-S和CFU-C是两类在性质上不全相同的干细胞群。在目前尚未建立起除啮齿类动物以外的多向性造血干细胞测定技术的情况下,我们应用体外琼脂培养技术,比较了在体外照射条件下狗与小鼠骨髓CFU-C的辐射敏感性,它们的D_0值分别为58.6拉德和190.2拉德,反映了两者在辐射敏感性上存在着明显的差异,为阐明不同种属动物的不同辐射耐受性提供了一个根据。联系到AET具有降低造血干细胞辐射敏感性以及提高动物的辐射耐受性的事实,进一步论证了在造血型放射病的发生和发展中,造血干细胞的损伤和修复是起着重要作用的。     

胸腺素组份5对小鼠造血干细胞的作用

实验采用超滤技术提纯的小牛胸腺素组份5(THF_5),对日龄50～60天、体重22～24g的瑞士纯种正常或照射小鼠,连续腹腔注射50、100、150μg,7和14天后,测造血干细胞(CFU-S)、粒系造血祖系细胞(CFU-C)及骨髓有核细胞。实验证明,THF_5不论对正常或照射小鼠的造血干细胞均有增殖作用,而且在一定范围内,给药剂量和CFU-S、cFU-C呈正相关。THF_5对850rad照射小鼠可提高活存率15～30％,与造血干细胞的变化是一致的。说明THF_5能促进受照射小鼠残存干细胞的增殖分化。     

分次和一次γ线照射所致小鼠骨髓造血细胞的损伤及恢复规律

研究了LACA小鼠经⁶⁰Coγ线分次和一次照射后骨髓CFU-S、CFU-C和CEU-E数量的动态变化.其D_c值在分次照射时分别为71.5、92.8和93.8拉德.一次照射时分别为86.5、113.5和41.7拉德.分次照射后上述三种细胞的数量立即恢复,而一次照射后头3天继续下降,第4天开始恢复,照射后CFu-S的分化不受其数量影响.照后早期CFU-S向CFU-E分化占明显的优势.讨论了分次照射时CFU-S和CFU-CD₀值较低的原因;CFU-S数量及其分化能力及照后恢复过程中CFU-S向CFU-C和CFU-E的竞争性分化及白细胞数量低下的原因.     

预先用环磷酰胺处理可促进照射小鼠造血干细胞的恢复

预先用长春花碱、长春新碱、环磷酰胺和阿糖胞苷等抗癌药处理,可促进全身照射后造血的恢复。在照后7天之内这种促进的恢复可使干细胞增多超过单纯照射对照的100倍,大大提高产生骨髓衰竭所需要的辐射剂量。单纯照射后观察到在干细胞恢复中发生延迟,干细胞数的增加乃是消除这种作用的结果。干细胞的辐射敏感性无变化。已证明用环磷酰胺处理小鼠使注入照射受体的正常骨髓细胞的再生增强。此种作用必然是由于改善细胞增殖的环境,而对宿主本身     

不同剂量γ射线照射后胎儿骨髓CD34~ 造血干细胞死亡规律

目的　探讨不同剂量γ射线照射后胎儿骨髓CD34 造血干细胞的死亡规律。方法　以流式细胞术PE -CD34 FITC AnnexinV 7AAD三色荧光法 ,多参数分析了受不同剂量γ射线照射后 ,不同时间点的胎儿骨髓CD34 造血干细胞凋亡、坏死和存活的时效和量效变化特点。结果　受大剂量率γ射线 1次 5Gy和 8Gy照射后 ,胎儿骨髓CD34 造血干细胞的死亡是在照射后为期 1周的连续性死亡 ,既有凋亡又有坏死 ,但是以凋亡为主 ;受大剂量率γ射线 1次 10Gy和 12Gy照射后 ,胎儿骨髓CD34 造血干细胞则在受照后当天即大量坏死 ,在持续 1周内全部死亡。结论　受大剂量率γ射线 1次照射后 ,造血干细胞在 1周内发生了增殖期死亡而连续性空出所占据的龛位     

The acutely limping child

Acute limping may be the result of multiple pathologies in children. The differential diagnosis varies based on the age of the child. Irrespective of age, the initial imaging work-up includes AP and frog leg radiographs of the pelvis and ultrasound; MRI may sometimes be helpful. In children less than 3 years, infections and trauma are most frequent. MRI is the imaging modality of choice when osteomyelitis is clinically suspected. Between the ages of 3 and 10 years, transient synovitis of the hip and Legg-Calvé-Perthes disease are main considerations but infection, inflammation and focal bony lesions are also considered. In children over 10 years, slipped capital femoral epiphysis also is considered.     

The role of interventional radiology in trauma

Introduction Interventional Radiology has evolved into a specialty having enormous input into the care of the traumatized patient.In all hospitals,regardless of size,the Interventional Radiologist must consider their relationships with the trauma service in order to     

Do Balance Board Training Programs Reduce the Risk of Ankle Sprains in Athletes?

Introduction Ankle sprains are the most common musculo-skeletal injury that occurs in athletes,particularly in sports that require jumping and landing on one foot such as soccer,and basketball(1-4).These injuries often result in significant time loss from participation,long-term disability,and have a major impact on health care costs and resources(5-8).     

Carbohydrate Supplementation during Exercise: Does It Help? How Much is Too Much?

KEY POINTS· Carbohydrate intake during exercise can delay the onset of fatigue and improve performance of prolonged exercise as well as exercise of shorter duration and greater intensity (e.g., continuous exercise lasting about 1h and intermittent high-intensity exercise), but the mechanisms by which performance is improved are different.     

Diagnóstico ecográfico del neumotórax

The ultrasonographic diagnosis of pneumothorax is based on the analysis of artifacts. It is possible to confirm or rule out pneumothorax by combining the following signs: lung sliding, the A and B lines, and the lung point. One fundamental advantage of lung ultrasonography is its easy access in any critical situation, especially in patients in the intensive care unit. For this reason, chest ultrasonography can be used as an alternative to plain-film X-rays and computed tomography in critical patients and in patients with normal plain films in whom pneumothorax is strongly suspected, as well as to evaluate the extent of the pneumothorax and monitor its evolution.     

High Intensity Interval Training:New Insights

KEY POINTS ·High-intensity interval training(HIT)is characterized by repeated sessions of relatively brief，intermittent exercise.often performed with an“a11 out”effort or at an intensity close to that which elicits peak oxygen uptake(i.e.，≥90%of VO2 peak).     

磁共振DWI和动态增强鉴别颅底脊索瘤和侵袭性垂体瘤的应用

目的 探讨磁共振扩散加权成像(DWI)和动态增强在颅底脊索瘤和侵袭性垂体瘤(IPA)鉴别诊断中的应用价值.方法 搜集经手术病理证实且影像学有鞍区破坏的颅底脊索瘤患者15例、向鼻咽部侵犯的IPA患者20例.测量二者的表观扩散系数(ADC)值,绘制受试者工作特征曲线(ROC),分析动态增强曲线的类型,统计达峰时间(TTP)、增强峰值(EP)和最大对比增强率(MCER),分析各个参数在鉴别诊断中的价值.结果 颅底脊索瘤的ADC值为(1.274±0.07)×10-3mm2/s,高于IPA ADC值(0.672±0.03) ×10-3 mm2/s(P ＜0.001),ADC阈值为0.964×10-3mm2/s时,ROC曲线下面积为0.997,敏感度为93.3％,特异度为100％.颅底脊索瘤时间-信号强度曲线(TIC)Ⅰ型14例,TICⅢ型1例,此例TICⅢ型者TTP约40 s;IPA TIC Ⅰ型7例,TICⅢ型13例.颅底脊索瘤和IPA的EP、MCER差异均有统计学意义(P ＜0.001).结论 ADC值和TIC的类型及其相关参数(EP,MCER)有助于颅底脊索瘤和IPA之间的鉴别.     

Treatment of intrahepatic arteriovenous fistula in hepatocellular carcinoma with N-butyl-2-cyanoacrylate

Primary hepatocellular carcinoma (HCC) continues to be one of the most common malignancies with an incidence of approximately one million cases per year and a dismal prognosis; some authors have reported a median survival of 1 ～ 2 months after diagnosis. Although surgery remains the only hope for cure, few patients are candidates[1,2].