葡多酚对辐射引发胰腺细胞Bcl-2和Bax蛋白异常表达的影响

目的探讨葡多酚（GPC）对亚慢性辐射引发的小鼠胰腺细胞凋亡及Bcl-2和Bax蛋白异常表达的抑制作用.方法给口服GPC的小鼠用60Co γ射线进行亚慢性辐照（每周5次,连续4周）,末次照射后第2天处死动物,取胰腺组织用免疫组化染色试剂盒测定Bcl-2和Bax表达水平、透射电镜观察细胞超微结构的变化.结果GPC保护组Bcl-2表达率为51.1%,较辐射对照组升高;而Bax表达率则低于辐射对照组;细胞超微结构损伤较辐射对照组减轻.各项差异均有统计学意义（P＜0.05）.结论GPC可抑制亚慢性辐射诱发的小鼠胰腺细胞凋亡及Bcl-2和Bax蛋白异常表达,对亚慢性辐射损伤有一定防护作用.     

全脑照射治疗大鼠癫痫的实验研究

目的 观察20Gy外照射对大鼠癫痫模型癫痫发作的影响，并着重检测该剂量照射后大鼠脑皮层内兴奋性氨基酸类递质—谷氨酸含量的变化。方法 建立戊四氮慢性癫痫模型，继以用20Gy剂量对模型大鼠皮层进行垂直照射。照射后48h，观察大鼠对致癫刺激的反应，并在接受致癫刺激后30min，取大鼠皮层，利用高压液相检测其中谷氨酸含量。结果 癫痫模型大鼠接受20Gy照射后48h，其癫痫发作明显受抑制。谷氨酸的检测结果显示，未接受照射的模型大鼠，受到致癫刺激后，脑内谷氨酸含量明显升高；而照射后的模型大鼠，接受相同刺激，脑内谷氨酸含量却没有明显升高。结论20Gy外照射后48h即可抑制模型大鼠癫痫发作，其抑制作用可能与照射降低了脑内兴奋性氨基酸类递质—谷氨酸的作用有关。     

不同剂量低强度激光血管内照射对实验性糖尿病兔红细胞变形能力的影响及其时间效应

本研究首次采用了较大的功率和剂量（５ｍＷ、１０ｍＷ、１８ｍＷ和２５ｍＷ×６０ｍｉｎ）的Ｈｅ－Ｎｅ激光对实验性糖尿病新西兰兔进行了血管内照射，观察了其红细胞变形能力（ＲＣＤ）随剂量和时间的变化。结果发现：①在未实验所选用的功率和剂量范围内，大剂量的照射对ＲＣＤ的影响能较早地表现出来，且更持久。②在改善ＲＣＤ的程度上，剂量（功率）越大，则越表现出优越性，特别是在照射后第１天和第３天，剂量越大的组其平均ＩＦ指数越小。③而照射１２天以后各组无显著性差异，则说明一次照射不可能使ＲＣＤ彻底恢复正常，所以在临床应用时，应进行多次照射。④从照后各天结果的相互比较可以看出，第三天的效果最好，这一结果可为疗程设计提供参考。未次实验过程中未发现溶血现象。     

Neurobehavioral study of prenatal exposure to hyperthermia combined with irradiation in mice

Thirty-two pregnant adult LACA mice were randomly assigned to one of five exposure groups: control, 38 °C, 42 °C. irradiation, and 42 °C + irradiation. Animals were exposed on gestation day 9 to either 38 °C waterbath for 5 min, 42 °C waterbath for 5 min, treatment with 0.5 Gy of ⁶⁰Co_γ irradiation, or pretreatment at 42 °C waterbath for 5 min following by 0.5 Gy of ⁶⁰Co_γ irradiation. On postnatal day 7, litters were reduced to a maximum of eight pups per litter, with equal members of male and female offspring whenever possible. A total of 216 pups were observed for the age of acquisition of four physiological landmarks (pinna detachment, incisor eruption, eye opening, testes descent), six developmental reflexes (surface righting, cliff avoidance, auditory startle, air righting, visual placing, hindlimb splaying), and examination of learning and memory function. These studies, at threshold exposure levels to hyperthermia and ionizing radiation, indicate there is no consistent significant additional postnatal effect when pregnant mice are exposed to both of these agents. These studies are important for our understanding of the relative long-range effects of prenatal exposure to hyperthermia and acute dose irradiation early in gestation on neurobehavioral teratogenesis.     

Tumor growth delay and cell survival after treatment with irradiation and vinblastine

The interaction of irradiation and vinblastine was investigated in a solid rat rhabdomyosarcoma. Growth delay of the tumor and cell survival by an in vitro assay were the endpoints measured. Vinblastine was administered at a dose of 1.5 mg/kg body weight at different time intervals before or after doses of 10 and 20 Gy of X-rays. Excess growth delay, i.e., the difference between observed growth delay for the combined radio-chemotherapy treatment and the sum of growth delays of individual treatments, was observed when vinblastine was administered at intervals of 1 to 12 days after or 2 to 8 days before the radiation doses.The clonogenic capacity of cells from tumors treated in vivo was messed using an in vitro survival assay. Cell survival data as a function of time after treatment with either vinblastine, a dose of 10 Gy of X-rays, or a dose of 10 Gy followed after 1 day by vinblastine were collected. The radiation treatment resulted in surviving fractions which remained constant up to 6 days after treatment. The effectiveness of vinblastine and of the combined treatments could be assessed 2 or 3 days after the drug application. The fractions of surviving cells determined after combined therapy were not significantly different from the fractions expected on the basis of simple multiplication of the fractions of surviving cells of individual treatments. This indicates that for a 1 day interval tumor growth delay observed after a dose of 10 Gy of X-rays followed by vinblastine correlates with a simple additional effect of the two individual treatments.     

Treatment of small cell carcinoma of lung with combined high dose mediastinal irradiation, whole brain prophylaxis and chemotherapy

Survival of patients with small cell carcinoma of lung, treated on a new combined radiotherapy-chemotherapy protocol, compares favorably with other regimens in the literature and our own previous combined approaches. Radiation, given after induction chemotherapy, consisted of whole brain prophylaxis in all 44 evaluable patients. Patients with limited disease were also treated to the primary and mediastinum to a high dose (5000 rad equivalent) using multiple fields. The new chemotherapy regimen consisted of induction with cyclophosphamide, doxorubicin, and vincristine alternated with cis-platinum and VP-16 (an epipodophyllotoxin) for two cycles, followed by consolidation with low dose cyclophosphamide and vincristine concurrent with irradiation. Patients with limited disease who achieved less than complete response, and all patients with extensive disease were not continued on maintenance chemotherapy. Out of 24 evaluable patients with limited disease, there was 73 % survival at 1 year by life-table analysis, measured from treatment initiation. After induction,$\text{16}\text{24}$ of these limited disease patients were CR (complete responders): $\text{20}\text{24}$ were CR at completion of their irradiation. Out of 20 evaluable patients with extensive disease, there was 59% survival at 1 year by life-table analysis. Only $\text{4}\text{44}$ (9%) brain parenchymal relapses occurred, one at 3 months and one at 6 months after local failure and two in patients who did not become CRs, implicating a possible re-seeding mechanism. Five patients had central nervous system relapses outside of brain parenchyma (spinal epidural and leptomeningeal); in three patients this was the initial site of failure. Significant complications included leukopenia (50% ) and thrombocytopenia (24% ) primarily during induction, and chronic pulmonary fibrosis (25% ), possibly contributing to two deaths.     

Cytotoxicities of mitomycin C and X rays to aerobic and hypoxic cells in vitro

Aerobic and hypoxic EMT6 mouse mammary tumor cells in exponential growth in vitro were used to study cell survival after treatment with radiation (250kV X rays) and mitomycin C in various combinations. The cytotoxicities of the two agents were found to be additive as judged by comparing dose-response curves for each agent alone with survival curves after combination therapy and by isobologram analysis. The cytotoxicities resulting from combination treatments were found to be independent of the sequence of the treatments or the interval between treatments.     

Effect of irradiation on lung metastasis of VX2 carcinoma in maxillary sinus of rabbit

Summary Effects of local single irradiation on lung metastasis of VX2 carcinoma transplanted in maxillary sinus of rabbits were evaluated. When an inadequate irradiation for complete regression was given, the rate of pulmonary metastases in irradiated groups was remarkably increased compared with non-irradiated one, although tumor growths in irradiated ones were apt to be inhibited corresponding to the given dose. Three parameters detected in the study related to general conditions were not so significantly different among the groups although those in irradiated groups were apt to be worse than those in control. Histologically most remarkable difference between in control and irradiated groups was stromal respose. However, on the question of whether stromal response could react as a diffensive or promotive mechanisms against tumor metastases, further studies would be needed including analysis of infiltrative cells.     

Biological consequences of the heterogeneous irradiation of lymphocytes during technetium-99m hexamethylpropylene amine oxime white blood cell labelling

Technetium-99m hexamethylpropylene amine oxime (^99mTc-HMPAO) labelling of white blood cells, routinely used for the detection of infection, results in the incorporation of radioactivity by polymorphonuclear leucocytes and also lymphocytes and can induce cell lesions in the latter case. The aim of this study was therefore to acquire data on the morphological and functional status of labelled lymphocytes present in the ^99mTc-HMPAO leucocyte mixture and to determine the cellular consequences of labelling. The mean radioactivity associated with lymphocytes was 325±10.8 kBq/10⁶ lymphocytes under standard labelling conditions. Microautoradiographic studies showed that labelling was heterogeneous (4% intensely labelled cells), which prevented calculation of the mean absorbed dose. The frequency of chromosomal aberrations (dicentrics and rings) in the labelled lymphocytes for 380 kBq/10⁶ cells was 1.08±0.09 but no abnormality was observed in the unlabelled control lymphocytes. The plating efficiency of labelled lymphocytes was reduced, as compared with that for control cells, but some lymphocytes were still able to form clones and were still ”alive” by radiobiological definition. It is therefore suggested that lymphocytes should be removed from ^99mTc-HMPAO cell preparations before administration to patients. Received 9 March and in revised form 1 June 1998