小肠上皮细胞电离辐射损伤修复的分子机制研究进展

小肠属于快速自我更新组织，隐窝细胞对细胞毒性损伤十分敏感，全身放射性损伤（核爆炸、核事故所致）以及腹部肿瘤局部放射治疗等都可引起肠道粘膜屏障受损和吸收功能障碍。另一方面，小肠上皮有独特的组织学结构，隐窝前体细胞区和绒毛分化细胞区有明显界限，细胞增殖、分化移行路线清楚，用射线诱导隐窝细胞凋亡，观察肠上皮细胞的反应和细胞更新是研究小肠干细胞生物学的重要手段。笔者介绍了小肠上皮细胞等级性排列特点，以及对电离辐射的敏感性，     

一例~(192)Ir极不均匀外照射局部极重度放射损伤的临床观察

目的对１例１９２Ｉｒ极不均匀外照射局部极重度放射损伤病人进行临床观察。方法系统观察了病变的临床过程和应用红外线热成像技术测定了损伤部位的温度变化。结果照射后２小时出现肢体麻木、抽搐，最早照后４小时出现红斑、肿胀，５４小时出现水疱，第５天出现坏死和剧痛，最晚出现红斑、肿胀是照射后４１天，４７天出现水疱和糜烂创面。红外线热成像显示：损伤早期温度升高，水疱、坏死区和损伤后期温度降低，温度升高越早，损伤越重，温度改变区域与损伤范围相一致。结论大剂量极不均匀外照射放射损伤的初期反应早，放射病与局部损伤相互加重病情，症状先后不一，轻重不等，致残率高和疼痛剧烈，红外线热成像温度变化可以作为临床诊断的指标之一。     

小肠和造血组织对芥子气中毒和辐射损伤的不同敏感性

芥子气中毒和辐射损伤的机理相似,均对细胞DNA有特异的损害。它们作用机体后,各组织均可出现不同程度的损伤,其中细胞分裂旺盛的组织损伤更为严重。辐射损伤后小肠和造血组织有明显的损伤作用,但是致死剂量辐射损伤引起死亡的主要原因为造血功能的抑制,死亡时间在照射10天以后。当射线剂量超过了致死剂量(1000拉德以上)时,才出现因小肠损伤所导致的3～5天内死亡。可是芥子气则不同,1个致死剂量中毒后在3～5天内即可死亡,而且伴随出现一系列严重的肠道症状。看来,两种组织(骨髓、小肠)对两种损伤(芥子气与射线)因素的敏感性是有所不同     

肠功能障碍诊治进展

对肠功能的认识始于肠衰竭概念的提出。20世纪80年代以后,认为以＂肠功能障碍＂一词替代＂肠衰竭＂更适合临床的情况与需要,这一概念的转变体现了从器官障碍到器官衰竭的病理过程。肠功能障碍可分为功能性小肠长度绝对减少型、小肠实质广泛损伤型和以肠黏膜屏障功能损害为主可同时伴有肠消化吸收功能的障碍三型。在胃肠道生理功能认识到胃肠道是人体四大菌库之首（其他为呼吸道、阴道、皮肤）,胃肠道是机体最大的免疫器官。直到今天,对胃肠道功能障碍与衰竭的定义还没有取得广泛的共识,更缺乏定量诊断标准。对于有关功能性小肠减少（一型）和小肠实质广泛受损（二型）的研究文献最多,这类肠功能障碍的主要治疗原则是替代和代偿。     

肠功能障碍诊治进展

对肠功能的认识始于肠衰竭概念的提出。20世纪80年代以后,认为以＂肠功能障碍＂一词替代＂肠衰竭＂更适合临床的情况与需要,这一概念的转变体现了从器官障碍到器官衰竭的病理过程。肠功能障碍可分为功能性小肠长度绝对减少型、小肠实质广泛损伤型和以肠黏膜屏障功能损害为主可同时伴有肠消化吸收功能的障碍三型。在胃肠道生理功能认识到胃肠道是人体四大菌库之首（其他为呼吸道、阴道、皮肤）,胃肠道是机体最大的免疫器官。直到今天,对胃肠道功能障碍与衰竭的定义还没有取得广泛的共识,更缺乏定量诊断标准。对于有关功能性小肠减少（一型）和小肠实质广泛受损（二型）的研究文献最多,这类肠功能障碍的主要治疗原则是替代和代偿。     

急性缺血性脑水肿微血管形态功能改变及高压氧治疗的效用

目的 探讨缺血性脑水肿脑神经细胞、微血管结构与功能的改变及高压氧治疗的效用。方法沙土鼠60只随机分成3组。阻断动物双侧颈动脉30min造成急性缺血性脑损伤，通过微循环显微镜和电镜观察动物缺血性脑水肿及高压氧治疗后微血管结构功能改变。结果高压氧暴露后，缺血性脑损伤动物大脑神经细胞肿胀改善，大多数神经细胞形态正常，微血管周围仅有少量渗出，内皮细胞损伤明显减轻，脑组织水肿开始吸收。缺血性脑损伤动物经0．25MPa高压氧暴露后，细动脉血流速度平均净增加0．88mm／s，细静脉净增加0．34mm／s。结论 高压氧暴露可通过减轻细胞损伤和改善微血管功能，达到对缺血性脑水肿的治疗作用。     

肠放射损伤的研究进展

电离辐射可引起生物体损害。消化道，尤其是小肠，对射线高度敏感。辐射损伤后，肠道黏膜屏障功能减弱甚至消失，肠道细菌及细胞分解产物进入血循环后引起的菌血症和毒血症是重要致死因素。笔者就肠道经中子和γ射线放射损伤的敏感性、病理特征、发生机理及防治等方面进行综述。     

小肠活动性出血的MDCT诊断

目的探讨小肠活动性出血的MDCT表现,为寻找小肠出血原因提供依据。方法采用多层螺旋CT(Phil-ips Mx 8000Dual CT和Philips Brilliance 64CT)对15例临床诊断小肠活动性出血患者进行平扫和双期增强扫描(25s和60s)。除急诊患者外,扫描前行清洁肠道准备,并口服20%甘露醇和清水作为阴性对比剂。增强扫描使用300mg/ml碘海醇肘部静脉注射。重建图象层厚2.0mm,结合多平面重组图像对小肠肠腔、肠壁形态及密度进行观察,寻找出血点,并分析其病因,MDCT结果与手术或内镜结果进行对照。结果对照平扫图像,增强后动脉期局部小肠腔内出现高密度对比剂、静脉期其形态及密度有改变为小肠活动性出血的直接征象。15例患者中MDCT发现13例阳性对比剂外溢至肠腔内,15例局部肠壁增厚或肿块,增强后较明显强化。阳性对比剂外溢对活动性小肠出血定位诊断的敏感性、特异性、阳性和阴性预测值分别为97%、100%、100%、88%。阳性对比剂外溢、局部肠壁增厚伴异常强化的位置与手术或内镜所见出血部位高度一致。结论增强后动脉期局部小肠腔内出现高密度对比剂、静脉期其形态及密度有改变为小肠活动性出血的特异性征象;局部肠壁增厚伴异常强化也提示该处为可能的出血点。MDCT可寻找小肠活动性出血部位并为明确病因提供依据,具有较高的临床应用前景。     

~(60)Co-γ线照射后小白鼠小肠长度及表面积的改变

小肠在哺乳动物胃肠道中的功能,主要是对营养物质的吸收,而其吸收能力则与其长度和粘膜表面积有一定的关系。因此曾有一些学者对人和其它哺乳动物的小肠长度进行过一些测量。也有些人做过一些测量粘膜表面积的尝试。哺乳动物受一定剂量的电离辐射全身或腹部局部照射,甚至照射置于腹腔外的肠道之后,就会发生肠型急性放射病。在这种类型的放射病中,胃肠道,特别是小肠,遭受到严重的辐射损伤。数十年来许多学者对小肠的辐射损伤及修复,不论在形态还是功能     

一例192Ir极不均匀外照射局部极重度放射损伤的临床观察

目的 对１例＾１９２Ｉｒ极不均匀外照射局部极重度放射损伤病人进行临床观察。方法 系统观察了病变的临床过程和应用红外线热成像技术测定了损伤部位的温度变化。结果 照射后２小时出现肢体麻木、抽搐，最早照后４小时出现红斑、肿胀，５４小时出现水疱，第５天出现坏死和剧痛，最晚出现红斑、肿胀是照射后４１天，４７天出现水疱和糜烂创面。红外线热成像显示：损伤早期温度升高，水疱、坏死区和损伤后期温度降低，温度升高越早     

Personal experience with examination of the small intestine using the enteroclysis method

Enteroclysis is rightly included to modern diagnostic methods for detecting damage to alimentary canal. It enables to visualize even small morphological changes on the mucous membrane of intestine, to prove fistulas if present and to evaluate functional changes if correctly applied. It significantly contributes to establishing early diagnosis in affections of the intestine and consequent use of adequate therapy. The authors in their communication summarized their experience, obtained in the examination of one hundred patients. They selected a modified procedure of examination according to Herlinger with the use of Prontobarium suspension and methyl cellulose. The application was made with a controlled duodenal probe from the Nicholas Company, introduced by nose. The average duration of one examination was 44 minutes.     

Short- and Mid-term Effects of Irreversible Electroporation on Normal Renal Tissue: An Animal Model

Purpose

Irreversible electroporation (IRE) is a novel nonthermal tissue ablation technique by high current application leading to apoptosis without affecting extracellular matrix. Previous results of renal IRE shall be supplemented by functional MRI and differentiated histological analysis of renal parenchyma in a chronic treatment setting.

Methods

Three swine were treated with two to three multifocal percutaneous IRE of the right kidney. MRI was performed before, 30 min (immediate-term), 7 days (short-term), and 28 days (mid-term) after IRE. A statistical analysis of the lesion surrounded renal parenchyma intensities was made to analyze functional differences depending on renal part, side and posttreatment time. Histological follow-up of cortex and medulla was performed after 28 days.

Results

A total of eight ablations were created. MRI showed no collateral damage of surrounded tissue. The highest visual contrast between lesions and normal parenchyma was obtained by T2-HR-SPIR-TSE-w sequence of DCE-MRI. Ablation zones showed inhomogeneous necroses with small perifocal edema in the short-term and sharp delimitable scars in the mid-term. MRI showed no significant differences between adjoined renal parenchyma around ablations and parenchyma of untreated kidney. Histological analysis demonstrated complete destruction of cortical glomeruli and tubules, while collecting ducts, renal calyxes, and pelvis of medulla were preserved. Adjoined kidney parenchyma around IRE lesions showed no qualitative differences to normal parenchyma of untreated kidney.

Conclusions

This porcine IRE study reveals a multifocal renal ablation, while protecting surrounded renal parenchyma and collecting system over a mid-term period. That offers prevention of renal function ablating centrally located or multifocal renal masses.     

Radiologic evaluation and staging of small intestine neoplasms

The small intestine is an uncommon location for neoplasms in either clinical or radiological practice. Because of its anatomic location and morphology, diagnosis of the diseases that affect small intestine pose difficulties. Symptoms are nonspecific and endoscopy is commonly unsatisfactory. Since early and definite diagnosis is crucial for prompt therapy, radiological imaging plays an essential role. Enteroclysis is the primary and effective radiologic modality in the evaluation of small bowel neoplasms. On the other hand, computed tomography should be the complementary radiologic method as well as for staging. In this review, the most common neoplasms of the small intestine and their common radiologic findings have been discussed.     

百草枯中毒肺损伤MSCT特征与临床预后相关性分析

目的:探讨百草枯中毒肺损害的MSCT表现及临床预后。方法:回顾性分析62例百草枯中毒患者的肺部CT表现及临床资料。结果:百草枯中毒时肺实质、肺间质均可受累。36例出现磨玻璃征和肺实变影,17例显示晚期肺纤维化。62例肺部CT表现与中毒剂量、检查时间相关。结论:百草枯中毒肺部损害具有明确的MSCT影像特征。早、中期以肺实质损害为主要CT表现,晚期以肺间质损害为主要CT表现。MSCT对判断肺损害、评估临床预后及制订治疗方案有重要意义。     

Experimental study of endoesophageal and intestinal expandable metallic stent placement

Gianturco expandable metallic stents were implanted into the esophagus and small intestine of 10 rabbits in order to evaluate the influence of wire stents on the gastrointestinal tract. The stents were constructed of 0.010 inch stainless steel wire. The relaxed diameter of the stents was 12-14 mm and the length was 10 mm. Except for one stent placed in the small intestine, the stents did not migrate and were covered with thickening mucosal epithelium. The mucosal inflammatory changes were slight, but severe intestinal adhesions were noted. The findings in the two groups were not significantly different at three and six weeks. Five rabbits died within three weeks of intestinal disorders caused by severe intestinal adhesions and/or perforations. The experimental data showed that implantation of metallic wire stents into the gastrointestinal tract resulted in severe damage to the esophagus and small intestine of rabbits.     

Fibrosing alveolitis--a contribution to the ultrastructure and pathogenesis of interstitial pulmonary diseases (author's transl)]

Considering the functional anatomy of the lung parenchyma the pathomorphological response pattern of the alveolus has been described. Hereby, the fibrosing alveolitis is conceived as an uniform concept of a disease, to which many different aetiological factors are associated. The ultrastructural pathology of early changes in fibrosing alveolitis has been described in the bleomycin lung as an example, which pathogenesis (as a chemically induced pulmonary damage) has a character of a model for the process of fibrosing alveolitis.     

Radiation effect in normal tissue - principles of damage and protection

The curative effectivity of external or internal radiotherapy necessitates exposure of normal tissues with significant radiation doses, and hence must be associated with an accepted rate of side effects. These complications can not a priori be considered as an indication of a too aggressive therapy. Based on the time of first diagnosis, early (acute) and late (chronic) radiation sequelae in normal tissues can be distinguished. Early reactions per definition occur within 90 days after onset of the radiation exposure. They are based on impairment of cell production in turnover tissues, which in face of ongoing cell loss results in hypoplasia and eventually a complete loss of functional cells. The latent time is largely independent of dose and is defined by tissue biology (turn-over time). Usually, complete healing of early reactions is observed. Late radiation effects can occur after symptom-free latent times of months to many years, with an inverse dependence of latency on dose. Late normal tissue changes are progressive and usually irreversible. They are based on a complex interaction of damage to various cell populations (organ parenchyma, connective tissue, capillaries), with a contribution from macrophages. Late effects are sensitive for a reduction in dose rate (recovery effects). A number of biologically based strategies for protection of normal tissues or for amelioration of radiation effects was and still is tested in experimental systems, yet, only a small fraction of these approaches has so far been introduced into clinical studies. One advantage of most of the methods is that they may be effective even if the treatment starts way after the end of radiation exposure. For a clinical exploitation, hence, the availability of early indicators for the progression of subclinical damage in the individual patient would be desirable. Moreover, there is need to further investigate the molecular pathogenesis of normal tissue effects in more detail, in order to optimise biology based preventive strategies, as well as to identify the precise mechanisms of already tested approaches (e.g. stem cells).     

双能量CT在肝实质弥漫性疾病中的应用进展

双能量CT是一种采用2种不同能量进行数据采集的成像技术,可选择多种算法进行影像后处理。基于物质分离算法的双能量CT可以定量分析肝实质内的脂肪、铁、碘等物质,有助于早期评估肝实质弥漫性疾病及其严重程度,为肝实质弥漫性疾病的早期诊断及其发展的监测提供了一种新的影像学方法。综述近年来双能量CT在脂肪肝、肝铁沉积症、肝硬化等肝实质弥漫性疾病方面的应用进展。     

早期促动力剂治疗对兔严重胸腹伤肠功能的影响

目的探讨兔严重胸腹伤后早期莫沙必利促肠道动力治疗对肠功能的影响。方法采用BIM-Ⅳ型生物撞击机建立实验性胸腹撞击伤动物模型,将30只新西兰兔随机分为正常对照组、创伤组和创伤促动力组,以观察小肠传输功能、小肠通透性、肠道细菌的移位及小肠黏膜形态学变化。结果创伤促动力组小肠传输功能恢复较快,肠通透性明显低于创伤组,肠道细菌移位率无明显差异。结论兔严重胸腹伤后早期采用莫沙必利促肠道动力治疗对肠传输及肠屏障功能有一定的保护作用。     

严重烧伤对大鼠肠三叶因子表达的影响

目的　探讨严重烧伤对大鼠肠三叶因子（ITF）及其mRNA表达的影响及意义。　方法　48只健康成年Wistar大鼠,制成30%TBSAⅢ度烧伤模型并随机分成正常对照组及伤后1,2,3,5,7d共6组,每组8只。采用原位杂交、免疫组化等手段观察伤后ITF及ITFmRNA表达的变化,并使用高效液相色谱仪对肠黏膜ITF含量进行定量检测。　结果　正常对照组大鼠小肠中ITF及ITFmRNA均有一定表达,它们主要分布于肠绒毛杯状细胞中。烧伤后肠黏膜组织结构受损,ITFmRNA表达明显减少,肠杯状细胞合成和分泌ITF的能力大幅下降（P<0.01）,特别是ITF二聚体的含量远远低于伤前［(369.33±65.56)ng/g］,伤后7d［(15.83±4.40)ng/g］仅为伤前的4%。　结论　严重烧伤后肠黏膜组织结构受损是ITF合成下降的主要原因,而ITF特别是ITF二聚体含量的大幅下降又可加重肠黏膜损伤,延缓肠黏膜修复。