Search

Chemotherapeutic drug resistance of tumor cells under hypoxic conditions is caused by the inhibition of apoptosis by autophagy and drug efflux via adenosine triphosphate (ATP)-dependent transporter activation, among other factors. Here, we demonstrate that disrupting glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression can reduce the autophagy and ATP levels in tumor cells. To test whether GAPDH knockdown is sufficient to overcome drug resistance, a nanocarrier (asymmetry-membrane liposome) was designed to encapsulate GAPDH-siRNA with a low dose of paclitaxel (PTX). Liposomes were prepared using novel cryogenic inner–outer dual reverse phase emulsion liposome manufacturing technology to obtain a high loading of siRNA. The results of dynamic light scattering (DLS) indicated that the liposomes had an average hydrodynamic diameter of 250.5 nm and polydispersity index (PDI) of 0.210, which was confirmed by (Transmission Electron Microscope) TEM images. In in vitro tests, the siRNA liposomes presented a high specificity in the suppression of GAPDH expression and significant synergy in cytotoxicity with co-delivery of PTX against tumor cells (HeLa and MCF-7) under hypoxic conditions. Moreover, in vivo studies (a HeLa tumor xenograft model using female BALB/c nude mice) demonstrate that the liposomes could not only increase the concentration of drugs in tumors over time but also successfully boosted the chemotherapeutic efficacy of PTX (synergistic therapy with GAPDH-siRNA). Tumor cells appeared to lose their resistance against PTX therapy, becoming more sensitive to PTX when GAPDH-siRNA was simultaneously administered in long-circulating liposomes. Consequently, the novel delivery of GAPDH-siRNA using nanotargeted liposomes provides a useful and potential tool to overcome multidrug resistant (MDR) tumors and presents a bright prospect compared with the traditional chemotherapeutic strategies in clinic cancer therapy.

The temporal characteristics of the Xe$^+$ ion axial Velocity Distribution Function (VDF) were recorded in the course of low-frequency discharge current oscillations ($\sim$~14 kHz) of the 5 kW-class PPS$\circledR$X000 Hall thruster. The evolution in time of the ion axial velocity component is monitored by means of a laser induced fluorescence diagnostic tool with a time resolution of 100 ns. As the number of fluorescence photons is very low during such a short time period, a hom-made pulse-counting lock-in system was used to perform real-time discrimination between background photons and fluorescence photons. The evolution in time of the ion VDF was observed at three locations along the thruster channel axis after a fast shut down of the thruster power. The anode discharge current is switched off at 2 kHz during 5 $\mu$s without any synchronization with the current oscillation cycle. This approach allows to examine the temporal behavior of the ion VDF during decay and ignition of the discharge as well as during forced and natural plasma oscillations. Measurements show that the distribution function of the axial component of the Xe$^+$ ion does change periodically in time with a frequency close to the current oscillation frequency in both forced and natural cases. The ion density and the mean velocity are found to oscillate whereas the velocity dispersion stays constant, which indicates that ionization and acceleration layers have identical dynamics. Finally, variations over time of the electric field are for the first time experimentally evidenced in a crossed-field discharge., Comment: 21 pages, 10 figures

To explain the principles and indications of gamma knife radiosurgery and to illustrate the correlated neuroimaging features.Between December 1999 and July 2007, 1620 patients were treated by GK for a large variety of indications (metastasis 26%, vascular malformations 7%, trigeminal neuralgia 14%, pituitary adenoma 3%, primary CNS tumour 8%, other tumours 6%, vestibular schwannoma 19%, meningioma 17%, functional disorders1%). The patients benefited from MRI follow-ups.MRI is the imaging technique of choice for Gamma knife radiosurgery (GKRS) in almost all indications. Computed Tomography, Digital Subtraction Angiography and Positron Emission Tomography have an additional role in some indications. Significant MRI data is illustrated in most indications. Evaluation of the treatment is mainly performed using MRI follow-up studies. The main features of these MRI follow-ups are described. Stabilisation or shrinking of the lesions volumes was generally observed. T2 relaxation times were also modified in and around the treated target areas, in patients responding to treatment and without any symptomatic complications. Modifications in contrast uptake were also observed in those patients. A few patients presented symptomatic complications associated with T2 signal anomalies. The interpretation of those modifications is discussed.MRI is the method of choice for GKRS planning in most indications. Imaging changes after radiosurgery provide the best quality control available to assess the response to radiosurgical treatment and to identify and monitor potential complications.

Sesame (Sesamum indicum L.) seed and oil have long been used widely as healthy foods to supply energy and prevent aging. Some of the main active anti-oxidative constituents in sesame seeds are γ-tocopherol and phenols. The purpose of this study was to investigate the relationship between roasting temperature and time with γ-tocopherol and total phenolic compounds (TPC) of sesame seeds when roasted in a domestic electric oven. Eight cultivars of sesame seeds in this study were Darab, Dezful, Karaj, Moghan, Naz- Branching, Naz-NonBranching, Siah and Varamin. Each cultivar was divided into ten group based on the roasting time (10, 15 and 20 min) and temperatures (180, 200 and 220 °C)andunroasted one. The high-performance liquid chromatography (HPLC) and spectrophotometeric methods were used for γ-tocopherol (n = 80) and TPC (n = 80) analysis, respectively. The γ-tocopherol content ranged from 329 ± 5 mg/L in Naz-Branching sesame oil to 1114±7 mg/L in Siah sesame oil and 169±6 to 577±1 mg/kg in sesame seed respectively. γ-tocopherol content of six cultivars increased significantly (p < 0.05) as the roasting temperature and time; until 200 °C for 10 min, but they were decreased by roasting at 220 °C in longer time. Also TPC increased significantly as the roasting temperature. The amount of TPC varied in different sesame cultivars from 20.109 ± 3.967 μM to 129.300±3.493 in Varamin and Naz- Branching sesame seed cultivars, respectively, also TPC increased from 70.953 ± 5.863 μM in unroasted Naz-Branching sesame seed to 129.300 ± 3.493 μM after roasting in 200 °C for 20 min. The present study showed that Iranian sesame seed can be considered as a good source of natural antioxidant specially after roasting. The optimum temperature and time roasting to obtain the most γ-tocopherol and total phenolic content was 200 °C for 10 and 20 min, respectively.

Technological developments arising from research have affected the whole wide spectrum of medical endeavor and have made a very significant impact on clinical practice and especially on imaging sciences. Ultrasonography brought spectacular advances, but CT and MRI became important landmark techniques. A further important development, which greatly increased the involvement of radiologists in direct patient management, was the growth of interventional and therapeutic techniques, called interventional radiology. Some statistics: approximately 155,000 patients per year including 19,000 CT Scans, 10,000 MRI exams, 21,000 ultrasound examinations and 1,000 therapeutic procedures. Some research activities: CT quantification of pulmonary emphysema, respiratory mechanics, MR and CT angiography, antenatal diagnosis of congenital and genetic diseases of the fetus, quantification of portal haemodynamics, MR imaging of bile and pancreatic ducts, morphologic and functional imaging of the brain, radiology of bone trauma, MR characterization in hepatic lesions.

Magnetic Resonance Imaging (MRI) has been introduced in clinical practice in the mid-eighties. However, MRI is an ever evolving imaging technique with constant new developments allowing broadening of clinical applications. In particular, angio-MRI involves many different acquisition techniques that will guide their clinical use. On the other hand, clinical applications of the following techniques are briefly discussed: diffusion, perfusion, tractography and diffusion tensor imaging, spectroscopy and functional imaging.

Background: The cause of osteoporosis is multifactorial and many dietary factors are important in the prevention of this disease. Antioxidants as free radical scavengers may influence osteoporosis by reducing the effects of oxidative stress that may be associated with bone loss. Vitamin E is an important antioxidant that protects polyunsaturated fatty acids (PUFA) in cell membranes from oxidation. There are only two studies regarding vitamin E plasma levels in subjects suffering from osteoporosis. The purpose of this study was to investigate the association between plasma vitamin E levels and bone mineral density (BMD) in Iranian patients. Methods: Subjects were consecutively recruited between May and September 2005 from among a total of approximately 1000 people referred for instrumental screening for osteoporosis to the Jami Clinic in Tehran. Inclusion criteria for the study group were: a femoral neck T-score of -1 or less, osteopenia, severe osteopenia and osteoporosis. A total of 137 subjects were enrolled. According to their femoral and spinal BMD scores, 54 persons were selected as a control group. The control group consisted of subjects with a femoral neck T-score and spine T-score of -1 or more. In selecting the case group, only the femoral BMD score was used. Plasma vitamin E was measured, after extraction with methanol, by HPLC with UV detection at 280 nm. Methanol, deionized water and butanol (90:4:6) was used as a mobile phase with a C8 column. The flow rate was 1.0 ml. min-1 and the acetate ester of vitamin E was used as an internal standard. Results: The results show no significant difference in plasma vitamin E between the control and case groups, however linear regression analysis does reveal a significant difference between the T-score and plasma vitamin E. Conclusion: Deceleration Femoral bone Density during osteoporosis will be Accelerated with Decrease of Vitamin E Antioxidant level.

International audience

BACKGROUND AND PURPOSE: Vascularity, metabolism, and histologic grade are related in gliomas but the exact determinants of these relationships are not fully defined. We used image coregistration and stereotactic biopsies to regionally compare cerebral blood volume (CBV) and (11)C-methionine (MET) uptake measurements in brain gliomas and to assess their relationship by histopathologic examination. MATERIALS AND METHODS: Fourteen patients with brain gliomas underwent MR imaging, including dynamic susceptibility contrast-enhanced MR and positron-emission tomography (PET) using MET acquired in identical stereotactic conditions before biopsy. MR-based CBV maps were calculated and both CBV maps and PET images were coregistered to anatomic images. Sixty-five biopsy samples were obtained on trajectories targeted toward high MET uptake area. The following histopathologic features were semiquantified in each sample: mitotic activity, endothelial proliferation, cellular pleomorphism, and tumor necrosis. CBV and MET uptake values were measured in the biopsy area and normalized to contralateral white matter. CBV ratios were compared with MET uptake ratios, and both measurements were compared with histologic features of each sample. RESULTS: CBV ratios ranged from 0.08 to 10.24 (median = 1.73), and MET uptake ratios ranged from 0.30 to 4.91 (median = 1.67). There was a positive correlation between CBV ratios and MET uptake ratios (r = 0.65, P < .001). Both CBV and MET uptake ratios were found to be significantly related to endothelial proliferation and mitotic activity (P < .01). CONCLUSION: Within glial tumors, there is a local relationship between CBV and MET uptake measurements. Both provide indices of focal malignant activity.