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1.
A previous preclinical study revealed that the maximal additive effect between chemotherapy (CT) and irradiation (RT) occurred at a low level of CT. Therapy was therefore designed with an oral drug daily given in combination with RT in order to determine the efficacy and toxicity. Locoregionally advanced head and neck tumor patients were treated with simultaneous RT and CT. RT was administered 5 times per week at 2 Gy per fraction in a total dose of 70 Gy. Throughout the treatment 30 mg/kg Tegafur was given daily orally. In the period between 2000 and 2002, 50 patients were enrolled. Complete remission was attained in 60%, with an overall response rate of 94%. Acute mucositis of grade 2 or 3 was observed in 56% (28 patients), and gastrointestinal and hematologic toxicity of grade 2 or 3 occurred in 8% (4 patients). Because of side-effects, the duration of treatment was at most 2 weeks longer. Toxicity was eliminated quickly by careful supportive therapy. In conclusion, it is considered that oral low-dose CT in combination with RT is an efficient and simple mode of treatment for locally advanced head and neck tumor patients with a poor prognosis.  相似文献   

2.
The frequency of reciprocal translocations (RT) in mouse spermatogonia induced by gamma-rays at doses of 1.5 to 4.5 Gy and dose rates of 2.7 X 10(-6), 5.8 X 10(-6), 9.4 X 10(-5) and 4.5 Gy/min was studied. A linear increase was observed in the RT frequency with increasing the dose, at all dose rates. At 9.4 X 10(-5) Gy/min the RT frequency was, on average, 10 times lower, as compared to that for a single acute dose rate of 4.5 Gy/min. Further reduction of the dose rate did not result in a decrease of the RT yield, and at the lowest dose rate of 2.7 X 10(-6) Gy/min (the dose being 3.0 Gy) the RT frequency was higher than using the same dose at dose rates of 5.8 X 10(-6) and 9.4 X 10(-5) Gy/min. Possible reasons for an increase in the RT frequency at low dose rates are considered. A study of the frequency of abnormal sperm heads (ASH) has shown that at the dose rate of 9.4 X 10(-5) Gy/min it is independent of an accumulated dose and is equal to the value obtained when exposing to an acute dose of 3.0 Gy. At dose rates of 2.7 X 10(-6) and 5.8 X 10(-6) Gy/min ASH frequencies were only slightly increased at all doses, as compared to the control level.  相似文献   

3.
Chromosomal aberrations in human sperm and lymphocytes were compared before and after in vivo radiation treatment of 13 cancer patients. The times of analyses after radiotherapy (RT) were 1, 3, 12, 24, 36, 48 and 60 months. The median total radiation dose was 30 Gy and the testicular dose varied from 0.4 to 5.0 Gy. Human sperm chromosome complements were analysed after fusion with golden hamster eggs. There were no abnormalities in sperm or lymphocytes before RT. Following RT there was an increase in the frequency of numerical and structural chromosomal abnormalities in both lymphocytes and sperm. For structural abnormalities there were more rejoined lesions (dicentrics, rings) in lymphocytes and more unrejoined lesions (chromosome breaks, fragments) in sperm. After RT there was a dramatic increase in the frequency of chromosomal abnormalities in lymphocytes: at 1 mo. the frequency was 42%, at 3 mo. 25%, at 12 mo. 14%, at 24 mo. 11%, at 36 mo. 9%, at 48 mo. 7% and at 6 mo. 4%. Since the majority of men were azoospermic after RT, there is little data on sperm chromosome complements before the analyses performed at 24 mo. post-RT. At 24 mo. the frequency of abnormalities was 13%, followed by 21% at 36 mo., 12% at 48 mo. and 22% at 60 mo. Thus it appears that the frequency of lymphocyte chromosomal abnormalities had an initial marked increase after RT followed by a gradual decrease with time whereas the frequency of sperm chromosomal abnormalities was elevated when sperm production recovered and remained elevated from 24 to 60 mo. post-RT. This difference in the effect of time makes it very difficult to compare abnormality rates in lymphocytes and sperm and to use analysis of induced damage in somatic cells as surrogates for germ cells since the ratio between sperm and lymphocytes varied from 1:1 (at 24 mo. post-RT) to 5:1 (at 60 mo. post-RT).  相似文献   

4.
《Free radical research》2013,47(10):1259-1268
Abstract

Background. The objective of the present study was to determine whether single administration of the antioxidant enzyme bovine superoxide dismutase (bSOD) after radiation therapy (RT) mitigates development of pulmonary toxicity in rats. Methods. Female F344 rats (n = 60) were divided among six experimental groups: (1) RT, single dose of 21 Gy to the right hemithorax; (2) RT + 5 mg/kg bSOD; (3) RT + 15 mg/kg bSOD; (4) No RT; (5) sham RT + 5 mg/kg bSOD; and (6) sham RT + 15 mg/kg bSOD. A single subcutaneous injection of bSOD (5 or 15 mg/kg) was administered 24 h post-radiation. The effects of bSOD on radiation-induced lung injury were assessed by measurement of body weight, breathing frequency, and histopathological changes. Immunohistochemistry was used to evaluate oxidative stress (8-OHdG+, NOX4+, nitrotyrosine+, and 4HNE+ cells), macrophage activation (ED1+), and expression of profibrotic transforming growth factor-β or TGF-β in irradiated tissue. Results. Radiation led to an increase in all the evaluated parameters. Treatment with 15 mg/kg bSOD significantly decreased levels of all the evaluated parameters including tissue damage and breathing frequency starting 6 weeks post-radiation. Animals treated with 5 mg/kg bSOD trended toward a suppression of radiation-induced lung damage but did not reach statistical significance. Conclusions. The single application of bSOD (15 mg/kg) ameliorates radiation-induced lung injury through suppression of reactive oxygen species/reactive nitrogen species or ROS/RNS-dependent tissue damage.  相似文献   

5.

Background and Purpose

For metastatic non-small cell lung cancer (NSCLC) patients with controlled extrathoracic disease after systemic treatment, stable or progressive primary lung lesions may cause respiratory symptoms and increase comorbidities. In the present study, we sought to investigate whether aggressive palliative thoracic radiotherapy (RT) can enhance local control and improve the survival for this subgroup of patients.

Materials and Methods

Between March 2006 and December 2014, 56 patients with metastatic NSCLC who had responsive or stable extrathoracic diseases after chemotherapy and/or molecular targets, and received thoracic RT for stable and progressive primary lung lesions were included. RT with a median dose of 55 Gy (range, 40–62 Gy) was administered in 1.8–2.5 Gy fractions to primary lung tumor and regional mediastinal lymph nodes using modern RT technique. Overall survival (OS) from diagnosis, and locoregional progression-free survival (LRPFS), and survival calculated from radiotherapy (OS-RT) were estimated using the Kaplan-Meier method.

Results

There were 37 men and 19 women with a median age of 60 years at diagnosis. The median interval from the diagnosis of metastatic disease to thoracic RT was 8 months. Following thoracic RT, 26 patients (46%) achieved complete or partial response (overall response rate, ORR). Patients with squamous cell carcinoma or poorly-differentiated carcinoma had a higher ORR than those with adenocarcinoma (63% vs. 34%, P = 0.034). EGFR mutations was closely associated with a better ORR (45% vs. 29%, P = 0.284). At a median follow-up time of 44 months, the median OS, LRPFS after RT, and OS-RT were 50 months, 15 months, and 18 months.

Conclusion

Radical palliative throractic RT is safe and might be beneficial for primary lung lesions of metastatic NSCLC patients with controlled extrathoracic diseases.  相似文献   

6.
The objective of this study was to determine whether administration of a catalytic antioxidant, Mn(III) tetrakis(N,N-diethylimidazolium-2-yl) porphyrin, AEOL10150, reduces the severity of long-term lung injury induced by fractionated radiation (RT). Fisher 344 rats were randomized into five groups: RT+AEOL10150 (2.5 mg/kg BID), AEOL10150 (2.5 mg/kg BID) alone, RT+AEOL10150 (5 mg/kg BID), AEOL10150 (5 mg/kg BID) alone and RT alone. Animals received five 8 Gy fractions of RT to the right hemithorax. AEOL10150 was administered 15 min before RT and 8 h later during the period of RT treatment (5 days), followed by subcutaneous injections for 30 days, twice daily. Lung histology at 26 weeks revealed a significant decrease in lung structural damage and collagen deposition in RT+AEOL10150 (5 mg/kg BID) group, in comparison to RT alone. Immunohistochemistry studies revealed a significant reduction in tissue hypoxia (HIF1α, CAIX), angiogenic response (VEGF, CD-31), inflammation (ED-1), oxidative stress (8-OHdG, 3-nitrotyrosine) and fibrosis pathway (TGFβ1, Smad3, p-Smad2/3), in animals receiving RT+AEOL10150 (5 mg/kg BID). Administration of AEOL10150 at 5 mg/kg BID during and after RT results in a significant protective effect from long-term RT-induced lung injury. Low dose (2.5 mg/kg BID) delivery of AEOL10150 has no beneficial radioprotective effects.  相似文献   

7.
We investigated the protective and therapeutic effects of molsidomine (MOL) in a rat model of whole brain radiotherapy (RT). Forty female rats were divided into five groups of eight: group 1, control; group 2, 15 Gy single dose RT (RT); group 3, 4 mg/kg MOL treated for 5 days (MOL); group 4, 4 mg/kg MOL for 5 days, 10 days after RT treatment (RT + MOL); group 5, 4 mg/kg MOL treatment for 5 days before RT treatment and for 5 days after RT treatment (MOL + RT). All rats were sacrificed on day 16. Neurodegenerative changes in the brain and tissue levels of oxidants and antioxidants were evaluated. The oxidative parameters were increased and antioxidant status was decreased in group RT compared to groups MOL + RT and RT + MOL. Histopathological examination showed that treatment with MOL after RT application and treatment with MOL before RT treatment decreased neuronal degeneration. No difference in neuronal appearance was found between groups RT + MOL and MOL + RT. MOL treatment protected the nervous system of rats and may be a treatment option for preventing RT induced neural injury.  相似文献   

8.
The radioprotective effect of 5-aminosalicylic acid (5ASA) was investigated in mouse bone marrow. The present study was aimed at investigating the radioprotective effect of pre-irradiation treatment with 5ASA against a range of whole-body lethal (8-11 Gy) and sublethal (1-4 Gy) doses of gamma-radiation (RT) in adult Swiss albino mice. Protection against lethal irradiation was evaluated from 30-day mouse survival and against sublethal doses was assessed from chromosomal aberrations in the bone marrow 24 h after irradiation. An intraperitoneal injection of 5ASA at a dose of 25mg/kg body weight (b. wt.) 30 min before lethal RT increased survival, giving a dose modification factor (DMF) of 1.08. Injection of 5ASA (25 mg/kg b. wt.) 60 or 30 min before or within 15 min after 3 Gy whole body RT resulted in a significant decrease in the radiation-induced aberrant metaphases, at 24 h post-irradiation. Maximum effect was seen when the drug was administered 30 min before irradiation. 5ASA (25 mg/kg b. wt.) significantly reduced the number of aberrant metaphases and the different types of aberrations at all the radiation doses (1-4 Gy) tested, giving a DMFs of 1.43 for number of aberrant metaphases. 5ASA pretreatment also significantly enhanced the endogenous spleen colonies in mouse exposed to 11 Gy RT. Pretreatment with 5ASA, protected plasmid DNA (pGEM-7Zf) against breakage induced by RT and Fenton reactants. Using nanosecond pulse radiolysis technique, the bimolecular rate constant of the reaction of 5ASA with hydroxyl radical was found to be 6.7x10(9)M(-1)s(-1). The p53 and p21 protein levels of bone marrow and spleen were evaluated to identify the specific molecular mechanisms. Both p53 and p21 increased 24h after 6 Gy irradiation, while treatment with 5ASA inhibited this RT-induced increase. Therefore, the present data suggest that 5ASA pretreatment decreases death caused by RT-induced gastrointestinal and hemopoeitic syndromes. The proposed mechanism of radioprotection by 5ASA is through the inhibition of damage to DNA, lipids, and proteins; and prevention of RT-induced increased expression of p53 and p21.  相似文献   

9.
Local delivery of high-energy ionizing radiation by using 3 or 3 emitters to injured vessels demonstrated inhibition of cell proliferation (CP) and neointima formation. Low-energy ('soft') X-radiation (LEXR) offers logistic and safety advantages over the use of disposable radioisotopes. This study evaluated the efficacy of LEXR in penetration and inhibition of CP at doses similar to those prescribed for the use of radioisotopes for prevention of restenosis. Serial measurements in an ion chamber detected the attenuation of LEXR using potentials of 17 and 40 kV at a distance of 17 cm of air through 0-10 mm depths of serum-containing tissue culture medium. The effect of inhibition on CP was determined by exposing V79 fibroblasts to a potential of 17 kV in order to deliver a prescribed dose of 13 Gy at a dose rate of 2.17 Gy/min to the surface of the cells. Complete inhibition of CP at a height of 0.00 mm occurred with 13 Gy; however, a 50% attenuation of the dose was measured at a medium depth of 1.22 mm and was associated with a reduction of 60% of the CP. LEXR demonstrated an ability to inhibit CP at doses equivalent to those used in techniques involving 3 and 3 irradiation. Under such conditions, the dose gradient is too high, especially for large vessels. However, a catheter-based LEXR that could be inserted into the artery with the capability of varying effective energy would be ideal for intravascular applications.  相似文献   

10.
To investigate the effects of ionizing radiation on an isolated neuronal network without complicating systemic factors, slices of hippocampus from the guinea pig were isolated and studied in vitro. Slices were irradiated with a 60Co source and compared to paired, sham-irradiated controls. Electrophysiological activity in the CA 1 population of pyramidal cells was evoked by stimulation of the stratum radiatum. Analysis of the somatic and dendritic responses suggested sites of radiation damage. Orthodromically evoked activity was significantly decreased in slices receiving greater than 75 Gy gamma radiation. The effects were dose and dose-rate dependent. At 20 Gy/min, doses of 50 Gy and greater produced synaptic impairment while doses of 75 Gy and greater also produced postsynaptic damage (i.e., the ability of the synaptic response to generate an action potential). A lower dose rate, 5 Gy/min, reduced the sensitivity of synaptic damage to radiation exposure; synaptic impairment required a dose of 100 Gy or greater at the lower dose rate. In contrast, postsynaptic damage was not sensitive to dose rate. This study demonstrates that ionizing radiation can directly affect the integrated functional activity of neurons.  相似文献   

11.
目的:观察调强适形放疗(intensity modulated radiation therapy,IMRT)联合多西他赛、奈达铂方案化疗同步治疗局部晚期食管癌的疗效及安全性。方法:选择66例局部晚期食管癌患者为研究对象,将其随机分为2组,其中常规放疗组(A组)共30例,采用常规照射方法,6/8 MV高能X线,2.0 Gy/次,5次/周;40 Gy/20次后再次定位剂量达60~66 Gy,强调放疗组(B组)共36例,采用强调适应性放疗,6/8MV-X射线照射,以95%等剂量线包绕PTV(计划靶区),处方剂量GTV(肿瘤区)66 Gy/30次,CTV(临床靶区)60 Gy/30次,PTV 60 Gy/30次,每天1次,每周5次。强调放疗组同期接受IMRT和多西他赛、柰达伯化疗,21天1个周期,连续2个周期。治疗结束后根据实体瘤疗效评价标准(RECIST)评定临床疗效;参照WHO毒性反应分度标准评价毒副反应。结果:常规放疗组和强调放疗组的总有效率分别为46.66%和91.67%(x2=17.26,P0.05);常规放疗组的毒副反应发生率显著高于强调放疗组,包括骨髓抑制、放射性食管炎和消化道反应的发生率存在显著差异(P0.05)。结论:调强适形放疗联合多西他赛、奈达铂化疗同步治疗局部晚期食管癌疗效较好,毒副反应可耐受,具有潜在的推广应用价值,值得临床进一步研究。  相似文献   

12.
The objective of this study was to determine the kinetics of nuclear factor-kappa B (NF-κB) activation and cytokine expression in bone marrow (BM) cells of exposed mice as a function of the dose rate of protons. The cytokines included in this study are pro-inflammatory [i.e., tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and IL-6] and anti-inflammatory cytokines (i.e., IL-4 and IL-10). We gave male BALB/cJ mice a whole-body exposure to 0 (sham-controls) or 1.0 Gy of 100 MeV protons, delivered at 5 or 10 mGy min−1, the dose and dose rates found during solar particle events in space. As a reference radiation, groups of mice were exposed to 0 (sham-controls) or 1 Gy of 137Cs γ rays (10 mGy min−1). After irradiation, BM cells were collected at 1.5, 3, 24 h, and 1 month for analyses (five mice per treatment group per harvest time). The results indicated that the in vivo time course of effects induced by a single dose of 1 Gy of 100 MeV protons or 137Cs γ rays, delivered at 10 mGy min−1, was similar. Although statistically significant levels of NF-κB activation and pro-inflammatory cytokines in BM cells of exposed mice when compared to those in the corresponding sham controls (Student’s t-test, p < 0.05 or <0.01) were induced by either dose rate, these levels varied over time for each protein. Further, only a dose rate of 5 mGy min−1 induced significant levels of anti-inflammatory cytokines. The results indicate dose-rate effects of protons.  相似文献   

13.
Role of radioadaptation on radiation-induced thymic lymphoma in mice   总被引:2,自引:0,他引:2  
Thymic lymphoma (TL) was observed in different stages of development in 46% of male mice (23/50) following exposure to an acute challenge dose of 2 Gy 60Co γ-rays. With an adapting dose of 1 cGy 24 h prior to the challenge dose of 2 Gy, similar growth of TL was seen in 42.5% of mice (17/40). TL was not found in unirradiated control mice (0/50) or in the group treated with 1 cGy (0/50). Multiple adapting doses for 5 or 10 consecutive days induced TL in 8/50 and 9/50 mice, respectively (17% in average). When multiple adapting doses were followed by the challenge dose, the yield of TL was much lower, 16% (8/50) and 30% (15/30), respectively. By 15, 30, 60, 90, and 120 days after exposure with 3 Gy of 60Co γ-rays, TL developed in 30, 70, 70, 80 and 85% of the female mice, respectively. When mice were conditioned with an adapting dose of 1 cGy 24 h prior to the challenge dose, TL was not found 15 days post-irradiation, while about a 25% reduction in the occurrence of TL was noticed at all other intervals. The results suggested that an adapting dose could play a role in bringing about a change in terms of delay and inhibition of the acute effects of radiation, i.e., the onset of TL in mice.  相似文献   

14.
Pulsed-dose-rate regimens are an attractive alternative to continuous low-dose-rate brachytherapy. However, apart from data obtained from modeling, only a few in vitro results are available for comparing the biological effectiveness of both modalities. Cells of two human cell lines with survival fractions of 80% (RT112) and 10% (HX142) after a single dose of 2 Gy and with different halftimes for split-dose recovery and low-dose recovery were used. The cells were irradiated with a continuous low dose rate (80 cGy per hour) or with pulsed dose rate. Two different pulsed dose rates were tested: 4.25 Gy/h and 63 Gy/h. The effects of dose per pulse and the length of the interval between the pulses were investigated while keeping the overall treatment time constant. Survival after low-dose-rate irradiation was indistinguishable from that after pulses of 4.25 Gy/h in cells of both cell lines. Survival decreased with increasing dose per pulse. When the dose rate during the pulses was increased, survival decreased even further. This effect was most pronounced for the radiosensitive HX142 cells. In clinical pulsed-dose-rate brachytherapy, iridium sources move stepwise through the implant and deliver pulses at a high dose rate locally. These high-dose-rate pulses produce greater biological effectiveness compared to continuous low dose rate; this should be taken into account.  相似文献   

15.
Mercury is a toxic and bio-accumulative heavy metal of global concern. While good deals of research have been conducted on the toxic effects of mercury, little is known about the mechanisms involved in the pathogenesis of male reproductive dysfunction induced by mercury. Therefore, the purpose of this study was to assess the effects and underlying mechanisms of chronic mercury exposure at low levels on male reproductive system of rats. Three-month-old male Wistar rats were divided into two groups and treated for 60 days with saline (i.m., Control) and HgCl2 (i.m. 1st dose: 4.6 µg/kg, subsequent doses 0.07 µg/kg/day). We analyzed sperm parameters, hormonal levels and biomarkers of oxidative stress in testis, epididymis, prostate and vas deferens. Mercury treatment decreased daily sperm production, count and motility and increased head and tail morphologic abnormalities. Moreover, mercury treatment decreased luteinizing hormone levels, increased lipid peroxidation on testis and decreased antioxidant enzymes activities (superoxide dismutase and catalase) on reproductive organs. Our data demonstrate that 60-day chronic exposure to low concentrations of HgCl2 impairs sperm quality and promotes hormonal imbalance. The raised oxidative stress seems to be a potential mechanism involved on male reproductive toxicity by mercury.  相似文献   

16.
Most cell lines that lack functional p53 protein are arrested in the G2 phase of the cell cycle due to DNA damage. It was previously found that the human promyelocyte leukemia cells HL-60 (TP53 negative) that had been exposed to ionizing radiation at doses up to 10 Gy were arrested in the G2 phase for a period of 24 h. The radioresistance of HL-60 cells that were exposed to low dose-rate gamma irradiation of 3.9 mGy/min, which resulted in a pronounced accumulation of the cells in the G2 phase during the exposure period, increased compared with the radioresistance of cells that were exposed to a high dose-rate gamma irradiation of 0.6 Gy/min. The D0 value (i.e. the radiation dose leading to 37% cell survival) for low dose-rate radiation was 3.7 Gy and for high dose-rate radiation 2.2 Gy. In this study, prevention of G2 phase arrest by caffeine (2 mM) and irradiation of cells with low dose-rate irradiation in all phases of the cell cycle proved to cause radiosensitization (D0=2.2 Gy). The irradiation in the presence of caffeine resulted in a second wave of apoptosis on days 5–7post-irradiation. Caffeine-induced apoptosis occurring later than day 7 post-irradiation is postulated to be a result of unscheduled DNA replication and cell cycle progress.  相似文献   

17.
Nineteen patients with Cushing''s disease were treated with low dose external pituitary irradiation (20 Gy (2000 rad) in eight fractions over 10 days). While awaiting the effects of pituitary irradiation all patients were treated with metyrapone. Seven patients had a complete remission of their disease within six to 12 months of irradiation. They did not require any further treatment and were followed up for a mean of three and a half (range one to eight) years. Another patient had a complete remission after a second course of pituitary irradiation. A further two patients showed a significant biochemical improvement after irradiation, although they were not rendered eucorticoid. There were no complications after this dose of irradiation. These results compare favourably with those reported after pituitary irradiation at conventional doses (40-50 Gy (4000-5000 rad) over four or five weeks) but were not associated with any complications. It is therefore recommended that low dose external pituitary irradiation be used as definitive first line treatment for Cushing''s disease.  相似文献   

18.

Background

Mycosis fungoides (MF) is a rare skin condition, effectively treated by irradiation. Since 1951, different methods of total skin irradiation have been developed. Although dose–response effect has been demonstrated in many publications, controversies about low dose treatment still exist.

Aim

The analysis of results of the total skin electron irradiation (TSEI), especially low dose TSEI in comparison with standard dose treatment is the subject of this review. Also, acute and late side effects of radiotherapy in MF are discussed.

Materials and methods

Medline search and analysis of studies published between 1995 and 2012, containing key words: mycosis fungoides, standard dose TSEI, low dose TSEI, total skin electron beam therapy (TSEBT).

Results

Detailed analysis of relevant studies demonstrated that standard dose radiotherapy 30–36 Gy is the most effective treatment used in clinical practice. Objective response rate (ORR) is high, especially for less advanced stages of disease. Complete response rate (CR), although slightly lower, is still relatively high.For more advanced MF, TSEI serves as a very good method of palliative treatment and relief of symptoms, like pruritus, pain or desquamation.There is no consensus regarding low dose TSEI; the method is widely accepted as a palliative treatment or in case of reirradiation.

Conclusions

Standard dose TSEI is an effective method of MF treatment for radical and palliative treatment, producing high rate of ORR and reasonably long time to progression (TTP). Acute and late side effect of treatment are mostly mild and easy to manage. Low dose TSEI is still in the phase of clinical studies.  相似文献   

19.
Response of a solid tumor to radiation treatment depends, in part, on the intrinsic radiosensitivity of tumor cells, the proliferation rate of tumor cells between radiation treatments and the hypoxic state of the tumor cells. A successful radiosensitizing agent would target S-phase cells and hypoxia. Recently, we demonstrated the anti-tumor effects of flavopiridol in the GL261 murine glioma model might involve 1) recruitment of tumor cells to S-phase (Newcomb et al., Cell Cycle 2004; 3:230-234) and 2) an anti-angiogenic effect on the tumor vasculature by downregulation of hypoxia-inducible factor -1? (HIF-1?) (Newcomb et al., Neuro-Oncology 2005; 7:225-235). Given that flavopiridol has demonstrated radiosensitizing activity in several murine tumor models, we tested whether it would enhance the response of GL261 tumors to radiation. In the present study, we evaluated the intrinsic radiation sensitivity of the GL261 glioma model using the tumor control/cure dose of radiation assay (TCD50). We found that a single dose of 65 Gy (CI 57.1-73.1) was required to cure 50% of the tumors locally. Using the tumor growth delay assay, fractionated radiation (5 fractions of 5 Gy over 10 days) combined with flavopiridol (5 mg/kg) given three times weekly for 3 cycles produced a significant growth delay. Our results indicate that the GL261 murine glioma model mimics the radioresistance encountered in human gliomas, and thus should prove useful in identifying promising new investigational radiosensitizers for use in the treatment of glioma patients.  相似文献   

20.
Thirteen patients with painful Paget''s disease of bone were treated as outpatients with low doses of synthetic salmon calcitonin 22·5-50 μg three times weekly. Treatment produced full remission of pain in a mean time of 5·5 weeks and a mean depression of serum alkaline phosphatase activity of 33%.The interval before symptomatic relief could not be predicted from the variables studied. The ultimate fall in serum alkaline phosphatase activity, however, could be predicted from the initial levels and from the early rate of decrease (P < 0·001). Biochemical resistance to treatment, which occurred in three cases, could be related to the dose and duration of treatment.Prolonged remissions of pain may occur which are not related to biochemical remission, to the dose of calcitonin, or to the duration of treatment. The side effects attributable to salmon calcitonin were transient nausea (in nine patients), transient flushing (in four), diarrhoea (in two), and rash (in one) though in only one patient did treatment have to be withdrawn prematurely because of these effects.  相似文献   

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