Pulse radiolysis studies of WR-1065

WR-1065, the dephosphorylated sulfhydryl form of WR-2721 has been suggested as the metabolite responsible for the radioprotective abilities of the latter and as being active during the radiation chemical stage of damage production. Hence this study was performed to determine some of the radiation chemical parameters of the compound. Pulse radiolysis techniques, developed for use with SH compounds, were employed in the current work: Three systems were used to attempt to measure the rate constant for reaction of OH. radicals with WR-1065; (a) Competition with phenylalanine, in which the decrease in the amount of RSSR- caused by the addition of phenylalanine is monitored; this failed because of the absence of an absorbance attributable to RSSR-. (b) Competition with 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS), monitoring the decrease in OH. induced ABTS absorbance caused by WR-1065 addition. This was unsuccessful due to reaction of RS. with ABTS. (c) Competition with CNS-, observing the decrease in (CNS)-2 caused by WR-1065 addition indicates that the second order rate constant for reaction of OH. with WR-1065 is 9.2 +/- 0.3 X 10(9) M-1 s-1. To investigate the ability of WR-1065 to react with DNA radicals the yield of ABTS radicals was monitored in a situation where DNA scavenges 50% of the OH. radicals in the presence of ABTS (20%) and WR-1065 (30%). DNA radicals were shown not to react with ABTS but WR-1065 radicals do, the absence of additional ABTS absorbing species indicates that DNA radicals do not react with WR-1065 under the experimental conditions used. An attempt was made to investigate the possibility that WR-1065 is concentrated close to DNA macromolecules in solution: The rate constant for reaction Br2- with WR-1065 was measured in the presence and in the absence of excess DNA (with which Br2- was not observed to react). The observed rates of reaction were independent of the presence of DNA indicating that the latter does not affect the availability of WR-1065 for reaction with Br2- radical. Reaction of WR-1065 with Br2- was used as a probe for determining the pK of the SH group. The rate of reaction increases from 1.8 X 10(8) M-1 s-1 at pH 6.3 to 1.6 X 10(9) M-1 s-1 at pH 8.4, the mid-point of the increase indicates a pK of 7.3.     

阿米福汀在肺癌放射治疗时对机体正常细胞和肺癌细胞的影响

目的　探讨阿米福汀对体外培养的中国仓鼠V79细胞和C5 7BL/ 6小鼠造血系统的放射保护作用及其在肺癌放射治疗时对肺癌组织生长的影响。方法　将体外培养的中国仓鼠V79细胞接种于培养皿后,分别给予2～10Gy的γ射线照射,用药组在照射前30min暴露于阿米福汀(1 2mmol/L) ,评价阿米福汀对照射后V79细胞存活分数的影响;给予C5 7BL/ 6无瘤小鼠腹腔注射阿米福汀(2 0 0mg/kg) 30min后进行全身照射(8Gy) ,在照射后不同时间观察外周血白细胞数量的变化;给予荷Lewis肺癌C5 7BL/ 6小鼠肿瘤局部照射10Gy ,照射前30min腹腔注射阿米福汀(2 0 0mg/kg) ,评价阿米福汀对肿瘤放疗效果的影响。结果　用药组V79细胞的集落存活分数高于单纯放射组(P <0 0 5 ) ;用药组无瘤小鼠外周血白细胞数较单纯放射组下降幅度小且恢复快(P <0 0 5 ) ;在观察的2 0d内,比较用药组和单纯放射组荷Lewis肺癌小鼠肿瘤体积,在相同时间点两组之间比较无显著性差异(P >0 0 5 )。结论　本研究从离体和在体两方面证实了阿米福汀对机体正常细胞产生放射保护的同时,对肿瘤组织细胞无放射保护作用     

Genistein对受辐射L-02人肝细胞增殖和DNA损伤的影响

[摘要] 目的 探讨金雀异黄素GEN（Genistein）对L-02人肝细胞DNA辐射损伤的防护作用。方法 实验分为正常对照组（N）,不同浓度GEN处理组（G）、单纯辐照组（R）和不同浓度GEN +辐照处理组（G+R）。L-02细胞分别用1,5,10,20μM GEN处理24h后,接受不同剂量X射线（4,6,8,12Gy）照射,继续培养48 h后利用MTT法检测GEN对细胞增殖率的影响,以确定有效辐射剂量及有效药物作用浓度;L-02细胞接受8Gy（300cGy/min）X射线照射后,利用单细胞凝胶电泳检测不同浓度GEN对细胞DNA辐射损伤的保护效果。结果 与N组相比,X射线剂量≧6Gy（300cGy/min）时,细胞增殖率随X射线剂量增加而显著降低（P<0.05）;1μM,5μM,10μM GEN处理细胞后增殖率随干预剂量增加而升高,5μM GEN处理后增殖率显著高于N组（P<0.05）; 照射剂量为6、8及12Gy时,5μＭGEN组细胞增殖率显著高于未处理组（P<0.05）。DNA损伤检测方面,N组和未照射各G组细胞未见拖尾,经8GyX射线照射后24h各组彗星发生率均小于1%,各组间彗星尾长无显著差异;照后48h, 单纯辐射组彗星发生率达到24.2%,彗星尾长达283.6±22.3μm,与单纯照射组相比,各浓度GEN组的彗星发生率和彗星尾长均显著降低（P<0.05）;照后72h,单纯辐射组彗星发生率较48h显著下降（P<0.05）,尾长显著缩短（P<0.05）,1μM、5μMGEN处理组彗星发生率和尾长仍显著低于单纯辐照组（P<0.05）,但10μM及20μMGEN组彗星发生率显著升高（P<0.05）,尾长显著增长（P<0.05）。 结论 低浓度（1μＭ、5μＭ）GEN能有效减轻X射线对L-02人肝细胞的DNA辐射损伤。     

抗放利对电离辐射诱导人外周血淋巴细胞遗传损伤的保护作用

目的 探讨2,2-二甲基四氢噻唑盐酸盐（抗放利）对辐射诱导人外周血淋巴细胞遗传损伤的防护作用。方法 采集健康人外周血,分为健康对照组、单纯照射组和抗放利防护组。照射剂量为2 Gy。抗放利防护组分0.2、0.5、1、2 mmol/L 4个浓度组,于照前30 min给药。通过染色体畸变分析、微核及单细胞凝胶电泳检测,观察抗放利对辐射致人外周血淋巴细胞遗传损伤的防护作用。结果 各浓度抗放利防护组与单纯照射组比较,染色体畸变率（t=5.34~25.48,P<0.05）、微核细胞率（t=5.18~29.44,P<0.05）与微核率（t=4.67~12.04,P<0.05）、彗星细胞尾长（t=16.18~19.64,P<0.05）、 尾矩（t=11.79~13.01,P<0.05）和Olive尾矩（t=12.44~14.88,P<0.05）、 尾部DNA含量（t=12.05~17.30,P<0.05）均明显降低。两个高浓度防护组（1、2 mmol/L）分别与两个低浓度防护组（0.2、0.5 mmol/L）比较,Olive尾矩明显降低（t=5.67~16.56,P<0.05）。2 mmol/L防护组与其余各防护组相比,微核率和微核细胞率明显降低（t=4.23~5.57,P<0.05）。结论 抗放利对辐射诱导人外周血淋巴细胞遗传损伤具有防护作用。     

Radioprotection in mice following oral delivery of amifostine nanoparticles

Purpose: Amifostine (Ethyol^®) is an approved cytoprotective agent prescribed to reduce certain side-effects in the chemotherapy of ovarian or non-small cell lung cancer, or in radiation treatment of head-and-neck cancer. The usefulness of this drug is further hampered, because it is not effective when given orally. The objective of this part of the project was to evaluate the radioprotective efficacy of orally active amifostine nanoparticles.

Materials and methods: Radioprotective efficacy was evaluated by measuring the ability of the amifostine nanoparticles (equivalent to 500?mg/Kg) to inhibit whole-body gamma irradiation -induced injury in mice. All mice received acute whole-body gamma irradiation from a Cesium-137 source and the radioprotective efficacy of the formulation was determined by measuring 30-day survival at 9?Gy, bone marrow hemopoeitic progenitor cell survival at 9?Gy and 8?Gy, and intestinal crypt cell survival at 11?Gy.

Results: Thirty-day survival, hemopoietic progenitor cell survival, as well as the jejunal crypt cell survival were all significantly enhanced when the mice were treated orally with the amifostine nanoparticles 1?h prior to irradiation.

Conclusions: These results clearly and unequivocally demonstrate that the amifostine nanoparticles developed in our laboratory provides significant protection from acute whole-body gamma irradiation injury in mice.     

How to operate kidney puncture in percutaneous nephrolithotomy?

Obtaining a precise percutaneous calyceal puncture gave way to the development of percutaneous nephrolithotomy, one of the first micro-invasive techniques described in urology. Both radiologist and urologist can perform puncture, sometimes in a collaborative effort. However, being followed by a true surgical procedure, it should be done in the O.R; perfect knowledge of the procedure is mandatory for every urologist. Standard guidance uses a fluoroscopic C-arm device, only able to guide the needle precisely towards the apex of the chosen calyx. Moving the C-arm with cephalad tilting will provide 3-D imaging. Ultrasound guidance is an alternative, but might be difficult with non dilated upper tract. CT guidance and retrograde puncture are rarely used. The access is to be adapted according to the patient (adult or child), type of stone (single or multiple access), or kidney position (eutopic or ectopic). Direct ad stable puncture entering the apex of the chosen calyx is a pre-requisite for easy and efficient subsequent nephrolithotomy.     

Protection of jejunal crypts by RH-3 (a preparation of Hippophae rhamnoides) against lethal whole body gamma irradiation

RH-3, an alcoholic extract of whole berries of Hippopheae rhamnoides, has been demonstrated to provide radioprotective activity in terms of survival of mice against whole body lethal irradiation (10 Gy). It was, therefore, investigated for its mode of action by monitoring crypt survival, cellularity of crypts and villi and the magnitude of apoptosis in the GI tract.Administration of RH-3 before irradiation (-30 min) increased the number of surviving crypts in the jejunum by a factor of 2.02 (p < 0.05) and villi cellularity by 2.5 fold (p < 0.05) in comparison to the irradiated control. RH-3 administration before irradiation also reduced the incidence of apoptotic bodies in the crypts (p < 0.05) in a time dependent manner and increased cellularity in the crypts and villi (84 h post irradiation) as compared to control. Caspase-3 activity was also significantly lower in the mice administered RH-3 before irradiation as compared to irradiated control.This study indicates that reduction in the radiation induced loss of cellularity of crypts and villi and also decrease in frequency of apoptosis could have contributed towards protection of mice treated with RH-3 before irradiation. The cellular and molecular mechanisms of radioprotection by Rh-3 need to be investigated further in detail.     

Measurement of irradiation doses secondary to bedside radiographs in a medical intensive care unit

The authors prospectively studied the radiation doses to radio-sensitive organs secondary to bedside radiographs in intensive care patients and in a control phantom. Dosimeters were taped on different organs during each bedside X-ray. The mean radiation doses, expressed in 10^-5 Gy (m-rad), for an average patient who was hospitalized 9 days and had 6 chest X-rays were respectively: 292 to the sternal bone marrow; 239 to the thyroid gland; 3 to the testes; 1 to the ovaries; 605 to the eye for 2 maxillary sinus X-rays. No diffused irradiation was measured during a 2-month period in the intensive care unit nor on dosimeters worn by four nurses.     

尼尔雌醇照前多次给药对骨髓型急性放射病小鼠的防护作用及其机制研究

目的 了解抗放药尼尔雌醇照前不同给药方案对⁶⁰Co γ射线照射所致小鼠骨髓型急性放射病的防护效应的影响,并揭示其促造血恢复机制。方法 采用外周血象分析和存活率实验确定尼尔雌醇较优给药方案,再以骨髓造血干/祖细胞表面标志分析、多系骨髓细胞集落及骨髓HE病理切片等方法,分析尼尔雌醇照前2次间隔给药促进照后骨髓造血恢复的作用机制。结果 尼尔雌醇照前3次间隔给药与2次间隔给药均能提高9.0 Gy照射小鼠存活率至100%,明显优于1次给药(20%, χ²=21.66、21.66,P<0.05)。尼尔雌醇照前3次连续给药与2次间隔给药均能改善6.5 Gy照射小鼠外周血白细胞、中性粒细胞、血小板和红细胞的恢复(F=21.33、100.9、49.34、19.19, P<0.05),且比1次给药效果好(F=17.11、63.38、21.89、14.37, P<0.05)。尼尔雌醇2次间隔给药显著提高6.5 Gy照射后小鼠10 d骨髓造血干、祖细胞数(t=8.58、2.80, P<0.05);显著增强小鼠骨髓造血细胞集落形成能力,与1次给药相比,差异有统计学意义(t=4.29、6.34, P<0.05)。同时,2次间隔给药明显改善照射小鼠骨髓象的重建。结论 与传统的照前单次给药相比,尼尔雌醇照前多次给药可显著提升其对小鼠骨髓型急性放射病的辐射防护效果。考虑到核医学应急救援的实际情况,建议尼尔雌醇照前采用间隔1 d的给药方式,在减少尼尔雌醇给药次数情况下,以获得最佳的抗放效果。     

抗癫痫药丙戊酸钠对大鼠正常脑组织的放射保护作用

目的 探讨丙戊酸钠(VPA)对大鼠正常脑组织的放射保护作用。方法 48只雄性Wistar大鼠随机分为VPA组、放疗组、联合组和对照组,每组12只。VPA组给予假照射和VPA注射(150 mg/kg,2次/d,共5 d);放疗组给予X线照射和生理盐水注射(150 mg/kg,2次/d,共5 d);联合组给予X线照射和VPA注射(150 mg/kg,2次/d,共5 d);对照组给予假照射和生理盐水注射(150 mg/kg,2次/d,共5 d)。放疗后24 h,采用免疫组化法检测脑组织Caspase-3的表达观察细胞凋亡。记录大鼠自VPA注射后2周内体质量变化。放疗后6个月,电镜观察脑组织神经元细胞核的改变。结果 免疫组化结果显示,放疗组与联合组相比可见明显Caspase-3表达。放疗组平均体质量明显低于其他各组,与联合组相比,体质量明显下降(P<0.05)。电镜结果显示,放疗组神经元核膜表面凹凸不平,不规整,甚至有损伤;联合组神经元核膜表面轻度不规整、没有损伤;对照组和VPA组神经元未见异常表现。结论 VPA对正常脑组织具有放射保护作用,其机制与抑制X线诱导的正常细胞凋亡有关。