A wax block was positioned between the rats’ heads and a 0.5 cm tissue equivalent bolus was placed on top to ensure full build
up of the dose at the skin surface. A dose of 15 Gy Trichostatin A manufacturer was prescribed at a 1.5 cm depth and delivered at a dose rate of 200 cGy/min (treatment planning system: Dosigray, DosiSoft, selleck chemical Cachan, France). After irradiations were completed, the animals were transferred to the Animal Care Facility at the ESRF. These irradiation parameters were chosen to be as close as possible to the Stereotactic synchrotron radiotherapy carried out at the European Synchrotron Radiation Facility (ESRF), which was previously described . Tumor imaging To confirm the presence of tumor, contrast-enhanced imaging was performed after radiotherapy using a conventional CT scanner (Siemens Somatom Plus 4 Volume Zoom scanner, Siemens Medical Systems, Iselin, NJ, USA). All of the animals received an intravenous (i.v.) injection of 1.5 mL of Iomeron® (350 mg/mL of iodine), followed by 0.5 mL of a saline solution (NaCl 0.9%) via the tail vein 10 minutes before computed tomography. Four animals showed no evidence of tumor at this time and they were excluded from the therapy studies. Statistical methods Kaplan-Meier survival plots were compared with the log-rank test (JMP, SAS Institute
Grégy sur-Yerres, France). The log-rank test statistic compares estimates of the hazard functions of the two groups at each observed event time. It is constructed by computing the IWR-1 molecular weight observed and expected number of events in one of the groups at each observed event time and then adding these to obtain an overall
summary across all time points where there is an event. The rats’survival were considered as significantly different when p < 0.05. Results Therapeutic response following i.c. of carboplatin in combination with 6 MV X-irradiation Survival data are summarized in Table 1 and Kaplan-Meier survival plots are shown in Figure 1. The survival plots of all treatment groups were significantly different from those of untreated controls (p < 0.02). Untreated rats had a mean survival time (MST) of 32 ± 2 d compared with 40 ± 3 d for 6 MV HSP90 X-irradiated animals. Rats that had received carboplatin alone had a median survival time (MeST) of 52 d and a censored MST of 71 ± 7 d, with 1 rat surviving more than 180 d, at which time the study was terminated. Animals that had received carboplatin, followed by X-irradiation with 6 MV photons, had a MST of > 126 ± 8 d and a MeST of > 180 d, with 6 of 11 rats (55%) alive at the end of the study. This was significantly different from irradiated animals (p <0.01) or those that had received carboplatin alone (p = 0.07).