硒抗辐射损伤作用的探讨

小鼠分次腹腔注射1.5mg Se/kg后,用^(60)Co 6.0Gy一次照射,观察硒对血及肝脏亚细胞组分线粒体GSHPx活性,LPO含量改变和~3H-TdR掺入的影响,以及在不同时间血和肝的GSHPx活性变化。并对不同剂量硒对LPO形成的影响进行了研究。结果表明,给硒及^(60)Co照射后小鼠体内的GsHPx活性显著增高;硒表现一定的抗辐射损伤作用和对损伤机体的恢复作用。另一方面,当给硒量在0.5mg/kg以上时,随着硒浓度的增加,LPO也增加,存在剂量效应关系。

脂膜微囊对大鼠脑射频损伤区亲和性的研究

目的观察脂膜微囊(LCM)在鼠脑损伤区域的密度分布特点;研究其在损伤后不同时相LCM对脑损伤区的靶点结合能力。方法建立大鼠脑射频损伤模型;于损伤后不同时相经尾静脉注射LCM混悬液,经荧光素及油红-O染色,观察并计数脑组织切片中的LCM。结果LCM主要聚集在脑损伤区周围2mm的范围内,伤后第10天与脑损伤区的靶点结合能力最强,出现密度高峰。结论LCM可以定向聚集于鼠脑损伤区周围,并在第10天达到聚集高峰;LCM有可能作为药物载体在脑损伤治疗中定向发挥药物疗效。

应用肌皮瓣治疗胸部放射性溃疡合并肋(软)骨炎

目的:探讨胸部放射性溃疡合并肋(软)骨炎的治疗方法.方法:彻底清除坏死、变性、感染的溃疡组织、肋(软)骨组织,扩大切除周边的瘢痕、纤维化组织后,应用下腹部横行腹直肌肌皮瓣和背阔肌肌皮瓣修复创面并部分再造乳房.结果:本组8例患者,创面应用下腹部横行腹直肌肌皮瓣4例,应用背阔肌肌皮瓣4例.其中7例伤口均2wk内愈合,1例术后因蒂部隧道周围死腔、积液引发局部感染,经部分拆线减小张力、湿敷换药、补充植皮后闭合创面.结论:应用肌皮瓣修复是治疗胸部皮肤放射性溃疡合并肋软骨炎的好方法.

基于数字预失真的发射机I/Q不平衡矫正

同相支路(I路)与正交支路(Q路)不平衡、载波泄漏以及带内失真会造成系统性能损失,尤其是在采用直接变频结构的发射机中。该文提出一种自适应I/Q不平衡矫正方案,针对发射机中存在的与频率相关的I/Q不平衡、载波泄漏以及带内失真进行矫正。该文方案直接估计I/Q两支路的反滤波器,避免了先求响应再求逆响应的额外运算,降低了运算复杂度。同时,该文还提出一种基于迭代的在线追踪方案,用于跟踪由于发射机温度变化造成的I/Q不平衡的参数漂移现象。经过复杂度分析,该文提出的方案拥有很高的补偿效率。最后,仿真结果验证了两种方案针对各类射频损伤矫正的有效性。

Novel damage constitutive models and new quantitative identification method for stress thresholds of rocks under uniaxial compression

Four key stress thresholds exist in the compression process of rocks,i.e.,crack closure stress(σ_(cc)),crack initiation stress(σ_(ci)),crack damage stress(σ_(cd))and compressive strength(σ_(c)).The quantitative identifications of the first three stress thresholds are of great significance for characterizing the microcrack growth and damage evolution of rocks under compression.In this paper,a new method based on damage constitutive model is proposed to quantitatively measure the stress thresholds of rocks.Firstly,two different damage constitutive models were constructed based on acoustic emission(AE)counts and Weibull distribution function considering the compaction stages of the rock and the bearing capacity of the damage element.Then,the accumulative AE counts method(ACLM),AE count rate method(CRM)and constitutive model method(CMM)were introduced to determine the stress thresholds of rocks.Finally,the stress thresholds of 9 different rocks were identified by ACLM,CRM,and CMM.The results show that the theoretical stress−strain curves obtained from the two damage constitutive models are in good agreement with that of the experimental data,and the differences between the two damage constitutive models mainly come from the evolutionary differences of the damage variables.The results of the stress thresholds identified by the CMM are in good agreement with those identified by the AE methods,i.e.,ACLM and CRM.Therefore,the proposed CMM can be used to determine the stress thresholds of rocks.

Damage and fracture behavior and spatio-temporal evolution of acoustic emission of sandstone before and after laser radiation

Laser technology holds significant promise for enhancing rock-breaking efficiency.Experimental investigations were carried out on sandstone subjected to laser radiation,aiming to elucidate its response mechanism to such radiation.The uniaxial compressive strength of sandstone notably decreases by 22.1%–54.7%following exposure to a 750 W laser for 30 s,indicating a substantial weakening effect.Furthermore,the elastic modulus and Poisson ratio of sandstone exhibit an average decrease of 33.7%and 25.9%,respectively.Simultaneously,laser radiation reduces the brittleness of sandstone,increases the dissipated energy proportion,and shifts the failure mode from tensile to tension-shear composite failure.Following laser radiation,both the number and energy of acoustic emission events in the sandstone register a substantial increase,with a more dispersed distribution of these events.In summary,laser radiation induces notable damage to the mechanical properties of sandstone,leading to a substantial decrease in elastic energy storage capacity.Laser rock breaking technology is expected to be applied in hard rock breaking engineering to significantly reduce the difficulty of rock breaking and improve rock breaking efficiency.

视黄酸调节EGFR和SP-A表达阻抑放射诱导肺损伤的探讨

目的:探讨视黄酸(RA)对放射性肺损伤模型大鼠支气管肺泡灌洗液(BALF)细胞数和EGFR及肺泡表面活性蛋白A(SP-A)表达的影响。方法:80只Wister大鼠随机分为正常对照组(A组)、单纯给药组(B组)、单纯照射组(C组)和照射加给药组(D组),C、D组大鼠行6MVX射线15Gy全胸野照射,B、D组给予20mg/(kg·d)RA制剂灌服,于照射后第1、2、4和8周行支气管肺泡灌洗及留取肺组织行HE、Masson染色及免疫组化法检测EGFR表达,蛋白质印迹法检测肺组织中SP-A蛋白表达。结果:放射组大鼠全胸单次15Gy照射后可以建立急性放射性肺损伤动物模型。与D组相比,C组BALF总数升高,肺内炎性渗出增多,胶原纤维增加,EGFR表达增强,以第4、8周最显著(P<0.01),C组各时间段SP-A蛋白表达均明显下降(P<0.001),以第1、8周最明显,第2、4周出现回升。B与C组各时间段相比SP-A蛋白表达差异无统计学意义。D组SP-A蛋白表达与C组比第1、8周差异无统计学意义,第2、4周均高于照射组(P<0.05),但仍低于正常组。结论:RA通过降低炎性细胞渗出,削弱EGFR和促进SP-A表达,预防放射性肺损伤的发生、发展。

The Expression of Apoptosis-Related Genes Bcl-2 and Bax Protein and Apoptosis Positivity in Cervical Carcinoma during Irradiation

To evaluate the apoptosis positivity, the expression of Bcl-2, bax proteinsin 30 patients with squamous cell cervix carcinoma before and after radiotherapy. Methods: By usingimmuno-histochemical and TDT-dUTP nick end labelling techniques, 30 cases of squamous cell cervicalcarcinoma were analyzed. Results: The apoptosis positivity before and after irradiation was 76.7%and 100% respectively, with the difference being significant (P 【 0.05); The positive rates of Bcl-2protein before and after irradiation were 73.3% and 46.7% respectively, with the difference beingsignificant (P 【 0.05); The positive rates of bax protein before and after irradiation were 86% and100% respectively, with the difference being significant (P 【 0.05). Conclusion: bax and Bcl-2protein play an important role in apoptosis induced by fractionated radiation therapy. Apoptosisinduced by irradiation is contributed to upregulation of bax protein or downregulation of Bcl-2protein.

Characterization of Ga NAs/ Ga As and Ga In NAs/ Ga As Quantum Wells Grown by Plasma-Assisted Molecular Beam Epitaxy: Effects of Ion Damage

The effects of ion damage on Ga NAs/Ga As and Ga In NAs/Ga As quantum wells ( QWs) grown by plas- ma- assisted molecular beam epitaxy have been investigated. Itis found thation damage is a key factor affecting the quality of Ga NAs and Ga In NAs QWs. Obvious appearance of pendello¨ sung fringes in X- ray diffraction pattern and remarkable im provement in the optical properties of the samples grown with ion removal magnets are observed.By removing nitrogen ions,the PL intensity of the Ga In NAs QW is improved so as to be comparable with that of Ga In As QW. The stronger is the magnetic field,the m ore obvious the PL intensity im provement would be.

Significance of endothelial dysfunction in the pathogenesis of early and delayed radiation enteropathy

This review summarizes the current state of knowledge regarding the role of endothelial dysfunction in the pathogenesis of early and delayed intestinal radiation toxicity and discusses various endothelial-oriented interventions aimed at reducing the risk of radiation enteropathy. Studies published in the biomedical literature during the past four decades and cited in PubMed, as well as clinical and laboratory data from our own research program are reviewed. The risk of injury to normal tissues limits the cancer cure rates that can be achieved with radiation therapy. During treatment of abdominal and pelvic tumors, the intestine is frequently a major close-limiting factor. Microvascular injury is a prominent feature of both early （inflammatory）, as well as delayed （fibroproliferative） radiation injuries in the intestine and in many other normal tissues. Evidence from our and other laboratories suggests that endothelial dysfunction, notably a deficiency of endothelial thrombomodulin, plays a key role in the pathogenesis of these radiation responses. Deficient levels of thrombomodulin cause loss of vascular thromboresistance, excessive activation of cellular thrombin receptors by thrombin, and insufficient activation of protein C, a plasma protein with anticoagulant, anti-inflammatory, and cytoprotective properties. These changes are presumed to be critically involved in many aspects of early intestinal radiation toxicity and may sustain the fibroproliferative processes that lead to delayed intestinal dysfunction, fibrosis, and clinical complications. In conclusion, injury of vascular endothelium is important in the pathogenesis of the intestinal radiation response. Endothelial-oriented interventions are appealing strategies to prevent or treat normal tissue toxicity associated with radiation treatment of cancer.

Clinical and dosimetric factors of radiation-induced esophageal injury: Radiation-induced esophageal toxicity

AIM: To analyze the clinical and dosimetric predictive factors for radiation-induced esophageal injury in patients with non-small-cell lung cancer (NSCLC) during threedimensional conformal radiotherapy (3D-CRT). METHODS: We retrospectively analyzed 208 consecutive patients (146 men and 62 women) with NSCLC treated with 3D-CRT. The median age of the patients was 64 years (range 35-87 years). The clinical and treatment parameters including gender, age, performance status, sequential chemotherapy, concurrent chemotherapy, presence of carinal or subcarinal lymph nodes, pretreatment weight loss, mean dose to the entire esophagus, maximal point dose to the esophagus, and percentage of volume of esophagus receiving ＞55 Gy were studied. Clinical and dosimetric factors for radiation-induced acute and late grade 3-5 esophageal injury were analyzed according to Radiation Therapy Oncology Group (RTOG) criteria.RESULTS: Twenty-five (12%) of the two hundred and eight patients developed acute or late grade 3-5 esophageal injury. Among them, nine patients had both acute and late grade 3-5 esophageal injury, two died of late esophageal perforation. Concurrent chemotherapy and maximal point dose to the esophagus ≥60 Gy were significantly associated with the risk of grade 3-5 esophageal injury. Fifty-four (26%) of the two hundred and eight patients received concurrent chemotherapy. Among them, 25 (46%) developed grade 3-5 esophageal injury (P = 0.0001＜0.01). However, nograde 3-5 esophageal injury occurred in patients who received a maximal point dose to the esophagus ＜60 Gy (P= 0.0001＜0.01).CONCLUSION: Concurrent chemotherapy and the maximal esophageal point dose ≥60 Gy are significantly associated with the risk of grade 3-5 esophageal injury in patients with NSCLC treated with 3D-CRT.

Cell cycle and radiosensitivity of progeny of irradiated primary cultured human hepatocarcinoma cells

AIM： To evaluate the change of growth characteristics and radiosensitivity of irradiated primary cultured human hepatocarcinoma cells. METHODS： All tumor tissue samples were obtained from 39 hepatocarcinoma patients with a mean age of 49.6 years （range 22-76 years）. We divided the samples into irradiated group and non-irradiated group and measured their plating efficiency （PE）, population doubling time （PDT）, radiosensitivity index SF2 and cell RESULTS： The PDT of primary culture of hepatocardnoma cells was 91.0±6.6 h, PE was 12.0±1.4%, SF2 was 0.41±0.05%. The PDT of their inadiated progeny was 124.8±5.8 h, PE was 5.0±0.7%, SF2 was 0.65±0.09%. The pdmary cultured human hepatocarcinoma cells showed significant S reduction and G^2 arrest in a dose-dependent manner. The progeny of irradiated primary cultured hepatocarcinoma cells grew more slowly and its radiosensitivity increased. CONCLUSION： The progeny of irradiated primary cultured human hepatocarcinoma cells grows more slowly and its radiosensitivity increases.

Hepatocyte growth factor gene therapy prevents radiation-induced liver damage

AIM: To transfer human HGF gene into the liver of rats by direct electroporation as a means to prevent radiationinduced liver damage.METHODS: Rat whole liver irradiation model was accomplished by intra-operative approach. HGF plasmid was injected into liver and transferred by electroporation using a pulse generator. Control rats (n = 8) received electrogene therapy (EGT) vehicle plasmid and another 8rats received HGF-EGT 100 μg 48 h before WLIR.Expression of HGF in liver was examined by RT-PCR and ELISA methods. Apoptosis was determined by TUNEL assay. Histopathology was evaluated 10 wk after whole liver irradiation.RESULTS: Marked decrease of apoptotic cells and downregulation of transforming growth factor-beta 1 (TGF-β1)mRNA were observed in the HGF-EGT group 2 d after liver irradiation compared to control animals. Less evidence of radiation-induced liver damage was observed morphologically in liver specimen 10 wk after liver irradiation and longer median survival time was observed from HGF-EGT group (14 wk) compared to control rats (5 wk). (P = 0.031).CONCLUSION: For the first time it has been demonstrated that HGF-EGT would prevent liver from radiation-induced liver damage by preventing apoptosis and down-regulation of TGF-β1.

Practical approaches to effective management of intestinal radiation injury:Benefit of resectional surgery

AIM:To study the outcome of patients undergoing surgical resection of the bowel for sustained radiation-induced damage intractable to conservative management.METHODS:During a 7-year period we operated on 17 cases (5 male,12 female) admitted to our surgical department with intestinal radiation injury (IRI).They were originally treated for a pelvic malignancy by surgical resection followed by postoperative radiotherapy.During follow-up,they developed radiation enteritis requiring surgical treatment due to failure of conservative management.RESULTS:IRI was located in the terminal ileum in 12 patients,in the rectum in 2 patients,in the descending colon in 2 patients,and in the cecum in one patient.All patients had resection of the affected region(s).There were no postoperative deaths,while 3 cases presented with postoperative complications (17.7%).All patients remained free of symptoms without evidence of recurrence of IRI for a median follow-up period of 42 mo (range,6-96 mo).CONCLUSION:We report a favorable outcome without IRI recurrence of 17 patients treated by resection of the diseased bowel segment.

Effects of UV-B radiation on tetraspores of Chondrus ocellatus Holm(Rhodophyta),and effects of red and blue light on repair of UV-B-induced damage

We evaluated the effects of red and blue light on the repair of UV-B radiation-induced damage in tetraspores of Chondrus ocellatus Holm. Tetraspores of C. ocellatus were treated with different UV-B radiation levels(0,36,72,108,144 and 180 J/m2),and thereafter subjected to PAR,darkness,or red or blue light during a 2-h repair stage,each day for 48 days. The diameters and cellular contents of cyclobutane pyrimidine dimmers(CPDs),chlorophyll a(Chl a),phycoerythrin,and UV-B-absorbing mycosporinelike amino acids(MAAs) contents of the tetraspores were determined. Our results show that low doses of UV-B radiation(36 and 72 J/m 2) promoted the growth of C. ocellatus; however,increased UV-B radiation gradually reduced the C. ocellatus growth(greater than 72 J/m2). The MAAs(palythine and asterina-330) in C. ocellatus were detected and analyzed by LC/MS. Our results suggest that moderate red light could induce the growth of this alga in aquaculture. In addition,photorepair was inhibited by red light,so there may be some other DNA repair mechanism activated by red light. Blue light promoted the activity of DNA photolyase,greatly improving remediation efficiency. Red and blue lights were found to reduce the capacity of C. ocellatus to form MAAs. Therefore,PAR,red light,and blue light play different roles during the repair processes for damage induced by UV-B radiation.

Protection of the liver against CCl_4-induced injury by intramuscular electrotransfer of a kallistatin-encoding plasmid

AIM:To investigate the effect of transgenic expression of kallistatin(Kal) on carbon tetrachloride(CCl 4)induced liver injury by intramuscular(im) electrotransfer of a Kal-encoding plasmid formulated with poly-Lglutamate(PLG).METHODS:The pKal plasmid encoding Kal gene was formulated with PLG and electrotransferred into mice skeletal muscle before the administration of CCl 4.The expression level of Kal was measured.The serum biomarker levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST),malonyldialdehyde(MDA),and tumor necrosis factor(TNF)-α were monitored.The extent of CCl 4-induced liver injury was analyzed histopathologically.RESULTS:The transgene of Kal was sufficiently expressed after an im injection of plasmid formulated with PLG followed by electroporation.In the Kal gene-transferred mice,protection against CCl 4-induced liver injury was reflected by significantly decreased serum ALT,AST,MDA and TNF-α levels compared to those in control mice(P < 0.01 to 0.05 in a dose-dependent manner).Histological observations also revealed that hepatocyte necrosis,hemorrhage,vacuolar change and hydropic degeneration were apparent in mice after CCl 4 administration.In contrast,the damage was markedly attenuated in the Kal gene-transferred mice.The expression of hepatic fibrogenesis marker transforming growth factor-β1 was also reduced in the pKal transferred mice.CONCLUSION:Intramuscular electrotransfer of plasmid pKal which was formulated with PLG significantly alleviated the CCl 4-induced oxidative stress and inflammatory response,and reduced the liver damage in a mouse model.

Biochemical metabolic changes assessed by ^(31)P magnetic resonance spectroscopy after radiation-induced hepatic injury in rabbits

AIM： To compare the features of biochemical metabolic changes detected by hepatic phosphorus-31 magnetic resonance spectroscopy （^31p MRS） with the liver damage score （LDS） and pathologic changes in rabbits and to investigate the diagnostic value of ^31p MRS in acute hepatic radiation injury. METHODS： A total of 30 rabbits received different radiation doses （ranging 5-20 Gy） to establish acute hepatic injury models. Blood biochemical tests, ^31p MRS and pathological examinations were carried out 24 h after irradiation. The degree of injury was evaluated according to LD5 and pathology. Ten healthy rabbits served as controls. The MR examination was performed on a 1.5 T imager using a 1H/^31P surface coil by the 2D chemical shift imaging technique. The relative quantities of phosphomonoesters （PME）, phosphodiesters （PDE）, inorganic phosphate （Pi） and adenosine triphosphate （ATP） were measured. The data were statistically analyzed. RESULTS： （1） Relative quantification of phosphorus metabolites： （a） ATP： there were significant differences （P 〈 0.05） （LDS-groups：control group vs mild group vs moderate group vs severe group, 1.83±0.33 vs 1.55±0.24 vs 1.27±0.09 vs 0.98±0.18; pathological groups： control group vs mild group vs moderate group vs severe group, 1.83±0.33 vs 1.58±0.25 vs 1.32±0.07 vs 1.02±0.18） of ATP relative quantification among control group, mild injured group, moderate injured group, and severe injured group according to both LDS grading and pathological grading, respectively, and it decreased progressively with the increased degree of injury （r = -0.723, P = 0.000）. （b） PME and Pi; the relative quantification of PME and Pi decreased significantly in the severe injured group, and the difference between the control group and severe injured group was significant （P 〈 0.05） （PME： 1DS- control group vs LDS-severe group, 0.86±0.23 vs 0.58±0.22, P = 0.031; pathological control group vs pathological severe group, 0.86±0.23 vs 0.60±0.21, P = 0.037; Pi： LDS-control group vs LDS-severe group, 0.74±0.18 vs 0.43±0.14, P = 0.013; pathological control group vs pathological severe group, 0.74±0.18 vs 0.43±0.14, P = 0.005） according to LDS grading and pathological grading, respectively. （c） PDE; there were no significant differences among groups according to LDS grading, and no significant differences between the control group and experimental groups according to pathological grading. （2） The ratio of relative quantification of phosphorus metabolites： significant differences （P 〈 0.05） （LDS- moderate group and LDS-severe group vs LDS-control group and LDS-mild group, 1.94±0.50 and 1.96±0.72 vs 1.43±0.31 and 1.40±0.38） were only found in PDE/ATP between the moderate injured group, the severe injured group and the control group, the mild injured group. No significant difference was found in other ratios of relative quantification of phosphorus metabolites.CONCLUSION： ^31p MRS is a useful method to evaluate early acute hepatic radiation injury. The relative quantification of hepatic ATP levels, which can reflect the pathological severity of acute hepatic radiation injury, is correlated with LDS.

收发信机射频损伤的UDN协同波束形成

为了进一步提高超密集无线网络(UDN)性能,提出一种同时考虑收发信机射频损伤的协同波束形成方法.首先,建立了包含射频损伤的UDN协同波束形成模型,并利用凸优化方法求解得到其最优解;然后,针对此最优解的结构特征,结合其在实际系统中难以实现的局限,设计了由信号泄漏噪声比波束形成导向矢量和最优功率分配构成的线性次优波束形成器.仿真结果表明,收发信机射频损伤的协同波束形成器能有效降低干扰,并且可提高UDN的系统容量.