Diagnostic Value of Model-Based Iterative Reconstruction Combined with a Metal Artifact Reduction Algorithm during CT of the Oral Cavity.

BACKGROUND AND PURPOSE: Metal artifacts reduce the quality of CT images and increase the difficulty of interpretation. This study compared the ability of model-based iterative reconstruction and hybrid iterative reconstruction to improve CT image quality in patients with metallic dental artifacts when both techniques were combined with a metal artifact reduction algorithm. MATERIALS AND METHODS: This retrospective clinical study included 40 patients (men, 31; women, 9; mean age, 62.9 ± 12.3 years) with oral and oropharyngeal cancer who had metallic dental fillings or implants and underwent contrast-enhanced ultra-high-resolution CT of the neck. Axial CT images were reconstructed using hybrid iterative reconstruction and model-based iterative reconstruction, and the metal artifact reduction algorithm was applied to all images. Finally, hybrid iterative reconstruction + metal artifact reduction algorithms and model-based iterative reconstruction + metal artifact reduction algorithm data were obtained. In the quantitative analysis, SDs were measured in ROIs over the apex of the tongue (metal artifacts) and nuchal muscle (no metal artifacts) and were used to calculate the metal artifact indexes. In a qualitative analysis, 3 radiologists blinded to the patients' conditions assessed the image-quality scores of metal artifact reduction and structural depictions. RESULTS: Hybrid iterative reconstruction + metal artifact reduction algorithms and model-based iterative reconstruction + metal artifact reduction algorithms yielded significantly different metal artifact indexes of 82.2 and 73.6, respectively (95% CI, 2.6-14.7; P < .01). The latter algorithms resulted in significant reduction in metal artifacts and significantly improved structural depictions(P < .01). CONCLUSIONS: Model-based iterative reconstruction + metal artifact reduction algorithms significantly reduced the artifacts and improved the image quality of structural depictions on neck CT images.

Basic properties of ATP-induced myosin head movement in hydrated myosin filaments, studied using the gas environmental chamber.

Although more than 50 years have passed since the monumental discovery of Huxley and Hanson that muscle contraction results from relative sliding between actin and myosin filaments, coupled with ATP hydrolysis, the mechanism underlying the filament sliding still remains to be a mystery. It is generally believed that the myofilament sliding is caused by cyclic attachment-detachment between myosin heads in myosin filaments and myosin-binding sites in actin filaments. Attempts to prove the myosin head movement using techniques of X-ray diffraction and chemical probes attached to myosin heads have failed to obtain clear results because of the asynchronous nature of myosin head movement. Using the gas environmental chamber (EC) attached to an electron microscope, we succeeded in recording myosin head movement in hydrated myosin filaments, coupled with ATP hydrolysis with the following results: (1)In the absence of actin filaments, myosin heads fluctuate around a definite neutral position, so that their time-averaged position remains unchanged; (2) On ATP application, myosin heads bind with ATP to be in the charged-up state, M-ADP-Pi, and perform a recovery stroke in the direction away from the myosin filament central bare zone and stay in the post-recovery stroke position; (3) In the actin-myosin filament mixture, myosin heads form rigor linkages with actin, and bind with applied ATP to be in the charged-up state, M-ADP-Pi, and perform a power stroke in the direction towards the myosin filament bare zone, while releasing ADP and Pi to stay in the post-power stroke position; (4) In both recovery and power strokes, myosin heads in the non charged-up state return to the neutral position. These results indicate that the charged-up myosin heads decide their direction of movement without being guided by actin filaments.

Results of a multi-institutional, randomized, non-inferiority, phase III trial of accelerated fractionation versus standard fractionation in radiation therapy for T1-2N0M0 glottic cancer: Japan Clinical Oncology Group Study (JCOG0701).

Background: We assessed the non-inferiority of accelerated fractionation (AF) (2.4 Gy/fraction) compared with standard fractionation (SF) (2 Gy/fraction) regarding progression-free survival (PFS) in patients with T1-2N0M0 glottic cancer (GC). Patients and methods: In this multi-institutional, randomized, phase III trial, patients were enrolled from 32 Japanese institutions. Key inclusion criteria were GC T1-2N0M0, age 20-80, Eastern Cooperative Oncology Group performance status of 0-1, and adequate organ function. Patients were randomly assigned to receive either SF of 66-70 Gy (33-35 fractions), or AF of 60-64.8 Gy (25-27 fractions). The primary end point was the proportion of 3-year PFS. The planned sample size was 360 with a non-inferiority margin of 5%. Results: Between 2007 and 2013, 370 patients were randomized (184/186 to SF/AF). Three-year PFS was 79.9% (95% confidence interval [CI] 73.4-85.4) for SF and 81.7% (95% CI 75.4-87.0) for AF (difference 1.8%, 91% CI-5.1% to 8.8%; one-sided P = 0.047 > 0.045). The cumulative incidences of local failure at 3 years for SF/AF were 15.9%/10.3%. No significant difference was observed in 3-year overall survival (OS) between SF and AF. Grade 3 or 4 acute and late toxicities developed in 22 (12.4%)/21 (11.5%) and 2 (1.1%)/1 (0.5%) in the SF/AF arms. Conclusion: Although the non-inferiority of AF was not confirmed statistically, the similar efficacy and toxicity of AF compared with SF, as well as the practical convenience of its fewer treatment sessions, suggest the potential of AF as a treatment option for early GC. Clinical trials registration: UMIN Clinical Trial Registry, number UMIN000000819.

Efficacy and Feasibility of Low-Dose Rate Brachytherapy for Prostate Cancer in Renal Transplant Recipients.

BACKGROUND: In young patients with localized prostate cancer, radical prostatectomy is the treatment of choice in the general population. Radiotherapy, such as low-dose rate (LDR) brachytherapy or intensity-modulated radiotherapy, is a viable alternative as well. However, in transplant patients, irradiation is not proposed as often as it is in healthy adults because of the risk of post-radiation ureteral stenosis and gastrointestinal toxicity as the result of fragile tissue. The objective of the study was to assess the efficacy and feasibility of LDR brachytherapy for prostate cancer in renal transplant recipients (RTRs). METHODS: Between May 2007 and December 2014, all patients who had undergone LDR brachytherapy for clinically localized prostate cancer at our institution were retrospectively identified (n = 203). Of these patients, 2 had a history of renal transplantation. We reviewed all available clinical data retrospectively. One patient had a functioning graft and the other had re-started hemodialysis 7 years after the transplantation. RESULTS: The mean time from renal transplantation to prostate cancer diagnosis was 16 years. The mean follow-up after seed implantation was 45 months. There were no peri-operative complications after seed implantation. The 2 patients remained free of prostate-specific antigen progression during the follow-up period. The renal function of the patient with a functioning graft, as measured by serum creatinine, was stable during and after the operation. CONCLUSIONS: LDR brachytherapy is technically feasible and acceptable as a minimally invasive treatment in carefully selected RTRs with localized prostate cancer. This treatment should be considered a suitable option for RTRs with localized prostate cancer.

Efficacy and Feasibility of Intensity-Modulated Radiation Therapy for Prostate Cancer in Renal Transplant Recipients.

BACKGROUND: In transplant patients with localized prostate cancer, irradiation is not proposed as often as it is in healthy adults because of the post-radiation risks, such as ureteral stenosis and gastrointestinal toxicity as the result of fragile tissue. The objective of the study was to analyze the efficacy and feasibility of intensity-modulated radiation therapy (IMRT) for prostate cancer in renal transplant recipients (RTRs). METHODS: Between May 2005 and December 2014, all patients who had undergone IMRT for clinically localized prostate cancer at our institution were retrospectively identified (n = 365). Of these patients, 2 had a history of renal transplantation. We reviewed all available clinical data. One patient had a functioning graft and the other had restarted hemodialysis 7 years after the transplantation. RESULTS: The mean time from renal transplantation to prostate cancer diagnosis was 11 years. The mean follow-up after irradiation was 43 months. The 2 patients remain free of prostate-specific antigen progression. There was no severe acute and chronic genitourinary and gastrointestinal toxicity. Renal function of the patient with a functioning graft as measured by serum creatinine was stable during and after the irradiation. CONCLUSIONS: IMRT is feasible and acceptable as a minimally invasive treatment in the carefully selected RTRs with localized prostate cancer. This treatment should be considered a good option for RTRs with localized prostate cancer.

Neuropathic Pain Features in Patients with Bone Metastases.

AIMS: The results of previous randomised controlled trials suggest that radiation oncologists should consider the presence of neuropathic pain when they prescribe dose fractionations for painful bone metastases. Although validated screening tools for neuropathic pain features are currently available, the prevalence of such features among patients with painful bone metastases is still poorly understood. The purpose of this study was to estimate the prevalence of neuropathic pain features among patients who received palliative radiotherapy for painful bone metastases. MATERIALS AND METHODS: We conducted a cohort survey of consecutive patients who received palliative radiotherapy for painful bone metastases at St Luke's International Hospital between 2013 and 2014. Patients were prospectively assessed before radiotherapy using the validated screening questionnaire to identify neuropathic pain components in Japanese patients. Pain with neuropathic features was prospectively defined using the total score of the seven-item questionnaire and a cut-off score ≥9. The pain response was assessed 2 months after the start of radiotherapy according to the criteria defined by the International Bone Metastases Consensus Working Party. RESULTS: Eighty-seven patients were assessed. Twenty-four per cent of patients (95% confidence interval: 16-35%) were diagnosed as having pain with neuropathic features. On multivariate analysis, no significant correlations were seen between neuropathic pain features and patient characteristics. Sixty-four patients (74%) were assessable 2 months after the start of radiotherapy. Overall response rates were 59% (95% confidence interval: 33-82%) in patients with neuropathic features and 55% (95% confidence interval: 40-70%) in those without such features. CONCLUSIONS: A considerable proportion of the patients were proven to have bone pain with neuropathic features. Further investigations are warranted to validate symptom assessment tools in cooperation with pain distribution and image findings, and to clarify if the presence of neuropathic pain affects the response to palliative radiotherapy.

Interleukin-10 expression induced by adeno-associated virus vector suppresses proteinuria in Zucker obese rats.

Varying degrees of metabolic abnormalities mediated by chronic inflammation are implicated in the chronic glomerular injuries associated with obesity. Interleukin (IL)-10, a pleiotropic cytokine, exerts anti-inflammatory effects in numerous biological settings. In the present study, we explored the biological benefits of adeno-associated virus (AAV) vector-mediated sustained IL-10 expression against the pathological renal characteristics observed in Zucker fatty rats (ZFRs). We injected an AAV vector, encoding rat IL-10 or enhanced green fluorescent protein (GFP) into male ZFRs at 5 weeks of age. Subsequently, the renal pathophysiological changes were analyzed. Persistent IL-10 expression significantly reduced the urinary protein excretion of ZFRs compared with GFP expression (47.1±11.6 mg per mg·creatinine versus 88.8±30.0 mg per mg·creatinine, P<0.01). The serum levels of IL-10 negatively correlated with the urinary protein in AAV-treated rats (r=-0.78, P<0.01). Renal hypertrophy, increased widths in the glomerular basement membrane, and the lack of uniformity and regularity of the foot process of the visceral glomerular epithelial cells of ZFRs were significantly blunted by IL-10 expression. IL-10 also abrogated the downregulation of glomerular nephrin observed in ZFRs treated with the GFP vector. Our findings provide insights into the potential benefit of the anti-inflammatory effects of IL-10 on the overall management of glomerulopathy induced by the metabolic disorders associated with obesity.

SU-E-T-488: Dose Calculation Model Using the Simplified Monte Carlo Method with an Initial Beam Model Adapted to a Beam-Wobbling System.

PURPOSE: We have developed an accurate dose calculation model based on a simplified Monte Carlo (SMC) method adapted to a beam-wobbling delivery system at National Cancer Center Hospital East (NCCHE). We used an initial beam model specific to the beam-wobbling system to reproduce accurately different dose distributions in two lateral directions (x- and y-directions) perpendicular to each other. METHODS: The SMC calculates a dose distribution by tracking individual protons. The SMC starts tracking protons at an entrance of a range compensator. Protons are generated in an initial phase space adapted to the wobbler system. Since two wobbling-magnets are located at separate places with different distances from the iso-center, different dose distributions are formed in x- and y-directions. We derived an initial phase space distribution for the beam-wobbling system using an analytical method. We used the SMC method with the initial beam model to calculate dose distributions accurately. To verify accuracy of the calculation method, we measured the dose distribution in a homogeneous phantom formed by 235 MeV protons passing through a L-shaped range compensator. We used a 2D-array of parallel-plate ionization chambers (2D Array seven29®) to measure dose distributions with a sampling period of 5 mm. RESULTS: The measured dose distribution in the x-direction was different from that in the y-direction. Our calculation model reproduces the measurement results well in both lateral directions. In addition, the calculation reproduced the dose increments in edge regions contributed by edge-scattered protons in collimator. It indicates the advantage of the SMC. CONCLUSIONS: A dose calculation model has been developed based on the simplified Monte Carlo method applied to a beam-wobbling system. By adapting the initial beam model to the wobbling system, the SMC method is found to reproduce observed different dose distributions in x- and y-directions well.

SU-E-J-31: Direct Point Dose Verification Using IGRT for Actual Beam Delivery.

PURPOSE: In radiation therapy, treatment planning for patients is performed using pre-acquired CT images. However, many patients with head-and-neck (H&N) cancer have tumor shrinkage and/or weight loss during their treatment course. Daily positional error of patients also causes unexpected deviations from the planning. Thus, it is essential to evaluate actual delivered dose for accurate clinical dosimetric consequence. In this study, actual delivered dose for an H&N site was determined by direct point dose measurement with metal-oxide-semiconductor field-effect transistor (MOSFET) detectors using IGRT procedure. We experimentally evaluated usefulness of the IGRT procedure for accurate irradiations. METHODS: Treatment processes from planning to beam delivery were performed for an H&N site of an anthropomorphic phantom. The MOSFET detectors were fixed inside the phantom in advance. Then, the anthropomorphic phantom was immobilized with a mould and mask and scanned by simulation-CT. Beam irradiation condition was field size of 12 cm × 12 cm, gantry angle of 0°, 90° and 330°, and 6 MV X-ray. Dose distribution was calculated with superposition algorithm with 2 mm calculation grid. Before the dose measurement, the anthropomorphic phantom was positioned using a localization system of mega-voltage cone-beam CT (MVCBCT). The MOSFET detectors were exposed five times according to a treatment plan. Measured doses with the MOSFET detectors were compared with calculated doses. RESULTS: Using the MVCBCT, the set-up of the anthropomorphic phantom was achieved within 1 mm in all directions of anterior/posterior, left/right, and superior/inferior. The calculated doses agreed well to the measured doses within ±3% even in evaluated region with high dose gradient. CONCLUSIONS: The actual delivered dose for an H&N site of an anthropomorphic phantom was evaluated experimentally with the MOSFET detectors. The IGRT procedure was useful for accurate irradiations.

Two cases of renal hypouricemia in which dopamine infusion produced a good recovery from exercise-induced acute kidney injury.

We report 2 cases with a good recovery from acute kidney injury (AKI) due to exercise-induced AKI associated with renal hypouricemia. Case 1 involves a 20-yearold man who had a similar episode 1 year earlier. He complained of nausea, vomiting and loin pain after playing football. On admission, his serum creatinine was 3.27 mg/dl and he was treated with intravenous fluid infusion (2 l/d). His renal function deteriorated and creatinine rose to 9.82 mg/dl. A renal hemodynamic evaluation using duplex Doppler ultrasound showed a high arterial resistance index (RI). After we changed his treatment to intravenous continuous infusion of 2 µg/kg/min dopamine, RI decreased sequentially and creatinine decreased without hemodialysis. A renal biopsy performed 7 days after dopamine infusion showed no changes in glomeruli and tubules, suggesting the absence of acute tubular necrosis, and no uric acid crystals or myoglobin casts in tubules. Case 2 involves a 42-year-old man who complained of loin pain after riding a motorcycle. On admission, his creatinine and creatine phosphokinase (CPK) were 3.93 mg/dl and 59 mU/ml, respectively. His RI was also high and he was treated immediately with an intravenous continuous infusion of 2 µg/kg/min dopamine. RI and creatinine decreased sequentially. Both cases suggest the effectiveness of dopamine infusion for AKI due to renal hypouricemia in which the RI of the renal arteries is high.

Virus activation and immune function during intense training in rugby football players.

Epidemiological studies suggest that highly trained athletes are more susceptible to upper respiratory tract infections (URTI) compared with the general population. Upper respiratory symptoms (URS) often appear as either primary invasion of pathogenic organisms and/or reactivation of latent viruses such as Epstein-Barr virus (EBV). The purpose of this study was to examine the relationship between EBV reactivation and the appearance of URS during intensive training in collegiate rugby football players. We evaluated EBV-DNA expression in saliva and examined the relationship between onset of URS and daily changes in EBV-DNA as well as secretory immunoglobulin A (SIgA) levels among 32 male collegiate rugby football players during a 1-month training camp. The EBV-DNA expression tended to be higher in subjects who exhibited sore throat (p=0.07) and cough (p=0.18) than that of those who had no symptoms, although their differences were not significant. The SIgA level was significantly lower 1 day before the EBV-DNA expression (p<0.05). The number of URS increased along with the EBV-DNA expression and decrease of SIgA levels. These results suggest that the appearance of URS is associated with reactivation of EBV and reduction of SIgA during training.

[The saccular coronary aneurysm associated with coronary artery to pulmonary artery fistulae].

Coronary artery fistulae are relatively rare congenital anomalies. Those associated with saccular coronary artery aneurysms are even rarer. Including the current case, only 65 such cases have been reported in Japan. A 62-year-old female was admitted to our hospital for evaluation of abnormal shadow on the chest X-ray. The enhanced chest computed tomography (CT) scan demonstrated a giant saccular coronary aneurysm on the left side of the pulmonary artery. Multi-detector row CT (MDCT) scan demonstrated the coronary artery aneurysm was connected to the left anterior descending artery. Coronary angiography revealed 2 aneurysms with bilateral coronary artery to pulmonary artery fistulae. The patient underwent aneurysmectomy and ligation of fistulae under cardiopulomonary bypass. The postoperative course was uneventful and postoperative coronary angiography revealed complete resection of the aneurysms and only slight blood flow through the fistulae. She was discharged on the 10th postoperative day.

[Perioperative coronary spasm in the modified Bentall's operation for localized dissecting aneurysm of Valsalva sinuses].

A 55-year-old man had suffered from chest oppression while asleep for 1 to 2 years. Moderate aortic regurgitation and aneurysm of Valsalva sinuses were revealed by echocardiography. It was diagnosed as chronic localized dissecting aneurysm of Valsalva sinuses during the operation, and modified Bentall's operation was performed. The patient was extubated 2 hours after the operation. ST segment depression in leads I, aV(L) and V3-V6, and elevation in leads III and aV(R) suddenly occurred 5 hours after the operation. However, hemodynamics was very stable, and he complained of no chest pain. Cardiac asystole was detected 7 hours after the operation, and percutaneous cardiopulmonary support as well as intraaortic balloon pumping (IABP) was immediately started. Emergency coronary angiography revealed acute myocardial infarction due to severe coronary spasm in the left coronary artery. The patient expired on the 3rd postoperative day.

[Isolated intracavitary metastatic hepatocellular carcinoma of the right atrium without inferior vena cava involvement; report of a case].

A 63-year-old female had been treated for liver cirrhosis and hepatocellular carcinoma (HCC) since 3 years before. She developed symptoms of dyspnea and echocardiography revealed a large tumor in the right atrium. The stalk of tumor was attached to the intraatrial septum just above the tricuspid valve and the tumor was floating between the right atrium and the right ventricle according to cardiac rhythm. The size of tumor was 30 x 15 mm in diameter. She was admitted to our hospital for emergency operation. She was operated for cardiac tumor under cardiopulmonary bypass successfully and the postoperative course was uneventful. But the pathology reported direct intracavitary metastasis of HCC without intravascular involvement. She was discharged on the 7th postoperative day for the treatment of HCC.

Psoriasis treated with ursodeoxycholic acid: three case reports.

We report three Japanese patients with psoriasis vulgaris associated with nonalcoholic fatty liver disease in which the skin lesions dramatically resolved after treatment of the fatty liver disease with ursodeoxycholic acid (UDCA). According to the literature, arachidonic acid is released from phospholipid by phospholipase A(2) (PLA(2)) and is a precursor of eicosanoids, including prostaglandins, leucotrienes, and thromboxanes, which are potent inflammatory mediators. PLA(2) activity has been reported to be significantly raised in the serum and skin tissue of patients with psoriasis. UDCA has been reported to suppress the increased activity of group IIA PLA(2), a secretory low-molecular-weight PLA(2) (PLA(2)IIA), in HepG2 cells (a human hepatoblastoma-derived cell line) and in gallbladder and gallbladder bile samples from patients with cholesterol stones. Thus, UCDA may improve the skin lesions of patients with psoriasis by suppressing PLA(2)IIA activity.

[Impending rupture of aneurysm of Salmonella-infected aortic arch].

We report a case of a 67-year-old man with Salmonella infected aortic arch aneurysm. The patient presented with persistent high fever, chest pain, back pain and hoarseness. Laboratory studies showed the presence of severe inflammation. Both impending rupture and saccular aneurysm were suspected by preoperative computed tomography (CT), magnetic resonance imaging (MRI) and angiography and diagnosis was, therefore difficult to make. We conducted semi-emergency total aortic arch replacement, under deep hypothermic circulatory arrest and retrograde cerebral perfusion. Salmonella was identified in the aneurysmal wall and antibiotics were administered for 6 weeks until CRP was normalized, when they were replaced by oral antibiotics. Postoperative course was uneventful. The patient was discharged on the 60th postoperative day. He continues to take oral antibiotics.

Heat shock protein 90 (Hsp90) chaperone complex inhibitor, radicicol, potentiated radiation-induced cell killing in a hormone-sensitive prostate cancer cell line through degradation of the androgen receptor.

Until now, there has not been enough information on how androgens or androgen deprivation may influence the response of cancer cells to radiation. In this study, the effect of dihydrotestosterone (DHT) on cellular proliferative activity and radiosensitivity was examined in a hormone-sensitive human prostate cancer cell line, LNCaP. In addition, the study also examined how a heat shock protein 90 (Hsp90) chaperone complex inhibitor modified the effect of DHT on the radiosensitivity of the cells, because binding of the androgen receptor (AR) to Hsp90 is required to maintain the stability and functioning of AR. The hormone-sensitive human prostate cancer cell line, LNCaP, was used. Radicicol was used as one of the known Hsp90 chaperone complex inhibitors, and the cells were incubated in the presence of this compound at a concentration of 500 nM. Cellular radiosensitivity was determined by the clonogenic assay; the changes in the protein expression were examined by Western blotting or immunofluorescence. DHT at a concentration of 1 nM caused enhancement of the proliferative activity and reduction of the radiosensitivity of the cells. Radicicol at a concentration of 500 nM abolished the DHT-induced decrease in cellular radiosensitivity and potentiated the radiation-induced cell killing synergistically. Consistent with the changes in the cellular radiosensitivity, radicicol degraded AR, Raf-1 and HER2/neu via reduced binding of AR to Hsp90, although selective degradation of HER2/neu caused by Herceptin, a monoclonal antibody against HER2, did not affect the cellular radiosensitivity. The results suggest that the Hsp9O chaperone complex may be a potential molecular target for potentiation of radiation-induced cell killing in a hormone-sensitive prostate cancer cell line.

Radicicol potentiates heat-induced cell killing in a human oesophageal cancer cell line: the Hsp90 chaperone complex as a new molecular target for enhancement of thermosensitivity.

PURPOSE: To examine the ability of a heat shock protein 90 (Hsp90) chaperone complex inhibitor, radicicol, to modify thermal response and heat-induced cell killing, and to clarify the underlining mechanisms. MATERIALS AND METHODS: A human oesophageal cancer cell line (TE-1), with a mutant p53 gene, was used. To examine the effect of radicicol on heat-induced cell killing, radicicol at a concentration of 100 nM was incubated with the cells for 7 h during heat treatment. Changes in the expression of proteins were examined by Western blot and immunofluorescence analysis. RESULTS: Radicicol in combination with heat synergistically potentiated heat-induced cellular killing despite an increase in the expression of Hsp72 and Hsp27 caused by radicicol. Heat alone activated Raf-1 and p42/p44 extracellular signal-regulated kinase (Erk), and heat in combination with radicicol inhibited the activation of Raf-1 and p42/p44 Erk through reduced binding of Raf-1 to Hsp90. Phosphorylation of Akt was also decreased by radicicol. CONCLUSIONS: The Hsp90 chaperone complex inhibitor, radicicol, potentiated heat-induced cellular killing, and inhibition of p42/p44 Erk and Akt activation rather than modification of Hsp expression might be involved in enhancing cellular thermosensitivity. Results suggest that the Hsp90 chaperone complex could be a new molecular target for the modification of the cellular response to heat.