半叶马尾藻多糖对［60Co］γ射线损伤小鼠骨髓细胞的影响

目的:探讨半叶马尾藻多糖(SHP)拮抗辐射损伤小鼠造血系统的机制。方法:流式细胞术检测小鼠骨髓细胞周期和Westernblotting测定细胞周期相关蛋白质CDK4的表达。结果:[60Co]γ射线(5Gy)导致小鼠骨髓细胞G0/G1期阻滞,而S期和G2/M期细胞百分率下降。SHP(10-40mg/kg)可以减轻小鼠骨髓细胞G0/G1期阻滞,增加S期和G2/M期细胞百分率,表现为SHP加照射组小鼠G0/G1期骨髓细胞百分率明显低于单纯照射组,S期和G2/M期骨髓细胞百分率显著高于单纯照射组。小鼠骨髓细胞CDK4蛋白质表达照射组明显低于正常对照组,SHP加照射组小鼠骨髓细胞CDK4蛋白质表达显著高于单纯照射组。结论:SHP拮抗[60Co]γ射线损伤小鼠骨髓细胞的机制与其调节骨髓细胞周期和增加CDK4蛋白质表达密切相关。     

职业性慢性放射病临床诊断及预后

目的：探讨慢性放射病（以下简称慢放病）的诊断、治疗及预后。方法：以受照剂量,临床症状,造血功能,Ｔ淋巴细胞百分率,染色体畸变率对３０例慢性放射损伤患者进行综合分析判断,对其中１１例慢放病用胸腺肽治疗并追踪观察１０年。结果：慢放病患者受照剂量超过２Ｓｖ,白细胞下降伴有几髓造血功能障碍,Ｔ淋巴细胞百分率下降,染色体畸变率显著上升。胸腺肽能改善临床症状,显著提高细胞免疫功能。慢放病各项指标恢复依时间顺序为：Ｔ淋巴细胞百分率（２年）,临床症状（３．５年）,造血功能（５～８年）,染色体畸变率（１０年）。结论：受照剂量是误断慢放病的重要依据;白细胞总数、骨髓造血功能改变是诊断的关键;Ｔ淋巴细胞百分率、染色体畸变率可作为鉴别诊断指标。慢放病是一种可以恢复的职业性疾病,胸腺肽治疗有助于慢放病的恢复。     

鼻咽癌放疗致位置性眩晕(附3例报告)

目的：探讨电离辐射对内耳前庭的影响。方法：报道鼻咽癌（ＮＰＣ）放疗致发作性位置性眩晕（ＢＰＰＶ）伴听力减退患者３例。采用耳石微粒复位法（ＰＲＭ）治疗ＢＰＰＶ,针对听力减退给予丹参治疗。结果：３例ＢＰＰＶ,２例痊愈,１例显效,听力下降的４耳语音频率平均提高１０ｄＢ。结论：ＢＰＰＶ可能与辐射所致的前庭损害有关,ＰＲＭ是治疗ＢＰＰＶ是一种有效方法。     

影响鼻咽癌病人受损颅神经恢复的因素分析

目的：探讨影响鼻咽癌病人受损颅神经恢复的相关因素。方法：１９８９年１月至１９９１年１月我科收治鼻咽癌伴颅神经受损病人１２８例,共２４５条颅神经受损。对影响受损颅神经功能恢复的可能因素进行单因素及多因素Ｃｏｘ模型分析。结果：放疗后１年内受损颅神经中有６５．７％（１６１／２４５）完全恢复,１９．２％（４７／２４５）部分恢复,１５．１％（３７／２４５）无变化,总的有效率为８４．９％（２０８／２４５）。单     

Steps to optimize transscleral photocoagulation

Background: In transscleral photocoagulation, the desired effect is coagulation of parts of the ciliary body or of the peripheral retina. However, the application is often limited by the unwanted effect of coagulation of the sclera. to reduce this effect, the ratio of incident radiation flux to radiation flux transported through the sclera (and able to coagulate the target tissue) should be minimized by the incident beam characteristics.Methods: Monte Carlo simulations for the radiation transport problem of multiple scattering in the sclera were used to calculate the ratio of transported to incident radiation for different parameter settings of beam diameters, optical thicknesses of the sclera and beam angles. To verify the theoretical calculations, an simple optical device utilizing a bulb instead of a laser source was constructed and applied to enucleated porcine eyes.Results: The theoretical calculations showed that the ratio of incident to transported radiation flux can typically be decreased by a factor of three by increasing the beam radius from 0.35 mm (as used in state-of-the-art laser devices) to 2 mm. This was confirmed by the experiments. Coagulations of the ciliary body or of the peripheral retina were possible with power densities an order of magnitude below the values normally applied with laser sources.Conclusion: To improve transscleral photocoagulation, beam diameters should be increased.     

Erbium filtration: a cost-effective, dose-reducing filter which maintains abdominal image quality

The current study investigated the effect of erbium filtration on an anteroposterior abdominal image. The radiation dose reductions achieveable and the costeffectiveness of this filter were also evaluated. An assessment of the radiation dose delivered employing either the standard total filtration (3 mm Al equivalent) or 0.1 mm of erbium filtration added to the standard filtration was undertaken on 21 patients. Image quality was assessed using the Commission of European Communities (CEC) criteria. Significant reductions of 64.6 % in entrance surface (p = 0.0001) and 23.4 % in effective dose (p = 0.0099) were recorded with erbium filtration. Image quality was maintained and the cost per manSievert saved was ￡ 128. More widespread use of this dose reducing filter is advocated. Received: 7 August 1998; Revised: 19 February 1999; Accepted: 19 April 1999     

Allergic skin reactions to anticonvulsant medications in patients receiving cranial radiation therapy

PURPOSE: Erythema multiforme and Stevens-Johnson syndrome have been associated with anticonvulsant medications (AEDs) in patients with brain tumors receiving cranial irradiation. AEDs are also known to cause mild drug rashes. The incidence of these complications has not been well studied among patients with brain tumors. We reviewed the records of patients with brain tumors treated with cranial radiation and AEDs to assess the frequency of both severe and mild skin reactions. METHODS: Retrospective review of 289 radiotherapy records of consecutively treated patients from 1988 to 1993. RESULTS: Only one of 289 patients developed erythema multiforme. Milder rashes, however, occurred in 18% of exposures to AEDs including 22% of exposures to phenytoin, compared with the expected rate of 5-10%. Most of the mild drug rashes occurred before the initiation of radiotherapy, suggesting that radiation was not the cause of these reactions. CONCLUSIONS: Severe skin rashes are rare among patients with brain tumors receiving radiation therapy and AEDs. There is, however, an increased frequency of mild drug rashes among patients with brain tumors that does not appear related to radiation.     

短小芽胞杆菌E601抗电离辐射性的研究

目的　短小芽胞杆菌Ｅ６０１ 已在中国确定为辐射灭菌指示菌。为使指示菌在灭菌过程中的应用标准化、规范化,保证灭菌质量,需要对其固有抗辐射性和影响因素,以及如何制备抗辐射稳定的生物指示剂作详尽研究。方法　应用钴６０γ射线和高能电子束对短小芽胞杆菌Ｅ６０１ 进行辐照,测定不同条件下的Ｄ１０ 值。结果　①因载体、介质不同,Ｄ１０ 值变化在１ ．６０ ～２．５３ｋＧｙ 之间。②不同温度下保存一年,指示菌片芽胞抗辐射性无明显变化。但随着保存时间延长,菌片上存活菌数逐渐减少。③载体、介质影响存活率,电子束与钴６０ 结果一致。结论　短小芽胞杆菌Ｄ１０ 值在１ ．６０～２．５３ｋＧｙ 之间,且抗性稳定。本试验条件下制备的可溶性菌片抗力高,Ｄ１０ 值为２ ．５３ｋＧｙ,可长期保存,适宜作指示剂应用     

Adjuvant and neoadjuvant chemoradiation therapy for primary colorectal cancer

The management of rectal cancer presents substantial challenges. Patients with T3 and/or node-positive rectal cancers are at high risk for local failure and distant metastases (DM). Adjuvant radiation has been shown to decrease local recurrence (LR) rates; however, this local therapy has not been demonstrated to improve survival when compared to surgery alone. In several prospective randomized trials adjuvant chemoradiation with 5-fluorouracil-(5-FU)-based chemotherapy improved LR rates, DM rates, and overall survival (OS). The optimal chemotherapeutic regimen has not been determined; however, studies comparing standard IV bolus 5-FU administration with continuous infusion (CI) 5-FU demonstrated that CI administration was superior. Preoperative therapy has potential advantages over adjuvant therapy such as less acute bowel toxicity and improved sphincter preservation. Preoperative chemoradiation has been shown in several studies to improve LR rates and OS when compared to surgery alone. Our current approach to patients with resectable T3 or N1 cancer in the distal two-thirds of the rectum on preoperative staging is preoperative chemoradiation with planned postoperative chemotherapy. This regimen offers the best chance for local control and disease-free survival while potentially downstaging the tumor and improving sphincter preservation.     

Flexure dose: the low-dose limit of effective fractionation

Total radiation dose often can be increased without subsequent increases in the severity of tissue injury by using reduced doses per fraction. The flexure dose, df, is defined as the largest fractional dose for which further fractionation produces no significant change in the total dose required to reach a specified effect level. Thus, df is clinically relevant in that it represents the limit of effective dose fractionation. For those tissues in which injury reflects depletion of a critical proportion of target cells, the flexure dose is a measure of the extent of the initial, nearly linear portion of the dose-survival curve. More generally, the flexure dose is a measure of the extent of the initial, nearly linear portion of a dose-response curve in organized tissue, whatever its relationship to clonogenic target cells might be. Several quantitative expressions for df are derived. The characteristic common to these is that each defines the flexure dose as a multiple of the ratio alpha/beta of the parameters of the linear-quadratic model of cell survival or dose response, where the multiple is a measure of experimental or statistical resolution. These multiples tend to fall within a limited range, thereby defining the "region of flexure" via the inequality 0.05 (alpha/beta) less than or equal to df less than or equal to 0.15 (alpha/beta). Estimates of the region of flexure are presented for a variety of normal and neoplastic tissues.