External photon radiation treatment for prostate cancer: Uncomplicated and cancer-free control probability assessment of 36 plans.

PURPOSE: To perform a systematic and thorough assessment, using the Uncomplicated and Cancer-Free Control Probability (UCFCP) function, of a broad range of photon prostate cancer RT treatments, on the same scenario (a unique pelvic CT set). UCFCP considers, together with the probabilities of local tumour control (TCP) and deterministic (late) sequelae (NTCP), the second primary cancer risk (SPCR) due to photon and neutron peripheral doses. METHODS AND MATERIALS: Thirty-six radiotherapy plans were produced for the same CT. 6, 10, 15 and 18 MV 3DCRT, IMRT and VMAT (77.4 Gy in 43 fractions) and 6 and 10 MV SBRT (36.25 Gy in 5 fractions with flattened and FFF beams) for Elekta, Siemens and Varian Linacs plans were included. DVH and peripheral organ dosimetry were used to compute TCP, NTCP, and SPCR (the competition and LNT models) for further plan ranking. RESULTS: Biological models (and parameters) used predicted an outcome which is in agreement with epidemiological findings. SBRT plans showed the lowest SPCR and a below average NTCPrectal. High energy plans did not rank worse than the low energy ones. Intensity modulated plans were ranked above the 3D conformal techniques. CONCLUSIONS: According to UCFCP, the best plans were the10 MV SBRTs. SPCR rates were low and did not show a substantial impact on plan ranking. High energy intensity-modulated plans did not increase in excess the average of SPCR. Even more, they ranked among the best, provided that MU were efficiently managed.

Correction: 3D VMAT Verification Based on Monte Carlo Log File Simulation with Experimental Feedback from Film Dosimetry.

[This corrects the article DOI: 10.1371/journal.pone.0166767.].

3D VMAT Verification Based on Monte Carlo Log File Simulation with Experimental Feedback from Film Dosimetry.

A model based on a specific phantom, called QuAArC, has been designed for the evaluation of planning and verification systems of complex radiotherapy treatments, such as volumetric modulated arc therapy (VMAT). This model uses the high accuracy provided by the Monte Carlo (MC) simulation of log files and allows the experimental feedback from the high spatial resolution of films hosted in QuAArC. This cylindrical phantom was specifically designed to host films rolled at different radial distances able to take into account the entrance fluence and the 3D dose distribution. Ionization chamber measurements are also included in the feedback process for absolute dose considerations. In this way, automated MC simulation of treatment log files is implemented to calculate the actual delivery geometries, while the monitor units are experimentally adjusted to reconstruct the dose-volume histogram (DVH) on the patient CT. Prostate and head and neck clinical cases, previously planned with Monaco and Pinnacle treatment planning systems and verified with two different commercial systems (Delta4 and COMPASS), were selected in order to test operational feasibility of the proposed model. The proper operation of the feedback procedure was proved through the achieved high agreement between reconstructed dose distributions and the film measurements (global gamma passing rates > 90% for the 2%/2 mm criteria). The necessary discretization level of the log file for dose calculation and the potential mismatching between calculated control points and detection grid in the verification process were discussed. Besides the effect of dose calculation accuracy of the analytic algorithm implemented in treatment planning systems for a dynamic technique, it was discussed the importance of the detection density level and its location in VMAT specific phantom to obtain a more reliable DVH in the patient CT. The proposed model also showed enough robustness and efficiency to be considered as a pre-treatment VMAT verification system.

Association of Bartonella spp bacteremia with Chagas cardiomyopathy, endocarditis and arrythmias in patients from South America

Infection with Bartonella spp may cause cardiac arrhythmias, myocarditis and endocarditis in humans. The aim of the present study was to evaluate a possible association between Bartonella spp bacteremia and endocarditis, arrhythmia and Chagas cardiomyopathy in patients from Brazil and Argentina. We screened for the presence of bacterial 16S rRNA in human blood by PCR using oligonucleotides to amplify a 185-bp bacterial DNA fragment. Blood samples were taken from four groups of subjects in Brazil and Argentina: i) control patients without clinical disease, ii) patients with negative blood-culture endocarditis, iii) patients with arrhythmias, and iv) patients with chronic Chagas cardiomyopathy. PCR products were analyzed on 1.5% agarose gel to visualize the 185-bp fragment and then sequenced to confirm the identity of DNA. Sixty of 148 patients (40.5%) with cardiac disease and 1 of 56 subjects (1.8%) from the control group presented positive PCR amplification for Bartonella spp, suggesting a positive association of the bacteria with these diseases. Separate analysis of the four groups showed that the risk of a Brazilian patient with endocarditis being infected with Bartonella was 22 times higher than in the controls. In arrhythmic patients, the prevalence of infection was 45 times higher when compared to the same controls and 40 times higher for patients with Chagas cardiomyopathy. To the best of our knowledge this is the first report of the association between Bartonella spp bacteremia and Chagas disease. The present data may be useful for epidemiological and prevention studies in Brazil and Argentina.

Association of Bartonella spp bacteremia with Chagas cardiomyopathy, endocarditis and arrhythmias in patients from South America.

Infection with Bartonella spp may cause cardiac arrhythmias, myocarditis and endocarditis in humans. The aim of the present study was to evaluate a possible association between Bartonella spp bacteremia and endocarditis, arrhythmia and Chagas cardiomyopathy in patients from Brazil and Argentina. We screened for the presence of bacterial 16S rRNA in human blood by PCR using oligonucleotides to amplify a 185-bp bacterial DNA fragment. Blood samples were taken from four groups of subjects in Brazil and Argentina: i) control patients without clinical disease, ii) patients with negative blood-culture endocarditis, iii) patients with arrhythmias, and iv) patients with chronic Chagas cardiomyopathy. PCR products were analyzed on 1.5% agarose gel to visualize the 185-bp fragment and then sequenced to confirm the identity of DNA. Sixty of 148 patients (40.5%) with cardiac disease and 1 of 56 subjects (1.8%) from the control group presented positive PCR amplification for Bartonella spp, suggesting a positive association of the bacteria with these diseases. Separate analysis of the four groups showed that the risk of a Brazilian patient with endocarditis being infected with Bartonella was 22 times higher than in the controls. In arrhythmic patients, the prevalence of infection was 45 times higher when compared to the same controls and 40 times higher for patients with Chagas cardiomyopathy. To the best of our knowledge this is the first report of the association between Bartonella spp bacteremia and Chagas disease. The present data may be useful for epidemiological and prevention studies in Brazil and Argentina.

SU-E-T-466: TCP and NTCP: Is That All?

PURPOSE: Concerns about the secondary cancer risks associated to the peripheral neutron and photon contamination in photon modern radiotherapy (RT) techniques (e.g., Intensity Modulated RT -IMRT- or Intensity Modulated Arc Therapy -IMAT) have been widely raised. Benefits in terms of better tumor coverage have to be balanced against the drawbacks of poorer organ at risk sparing and secondary cancer risk in order to make the decision on the optimum treatment technique. The aim of this study was to develop a tool which estimates treatment success taking into consideration the neutron secondary cancer probability. METHODS: A methodology and benchmark dataset for radiotherapy real time assessment of patient neutron dose and application to a novel digital detector (DD) has been carried out (submitted to PMB, 2011). Our DD provides real time neutron equivalent dose distribution in relevant organs along the patient. This information, together with TCP and NTCP estimated from the DVH of target and organs at risks, respectively, have been built into a general biological model which allows us to evaluate the success of the treatments (Sánchez-Nieto et al., ESTRO meeting 2012). This model has been applied to make estimation of treatment success in a variety of treatment techniques (3DCRT, forward and inverse IMRT, RapidArc, Volumetric Modulated Arc Therapy and Helical Tomotherapy) to low and high energy. RESULTS: MU-demanding techniques at high energies were able to deliver treatment plans with the highest complicated-free tumour control. Nevertheless, neutron peripheral dose must be taken into consideration as the associated risk could be of the same order of magnitude than the usually considered NTCPs. CONCLUSIONS: The methodology developed to provide an online organ neutron peripheral dose can be successfully combined with biological models to make predictions on treatment success taking into consideration secondary cancer risks.

Human adipose cells have voltage-dependent potassium currents.

The whole-cell patch-clamp method was used to study the membrane electrical properties of human adipocyte cells obtained by differentiating from precursors of human abdominal and mammary tissues. All differentiated cells exhibited outward currents with sigmoidal activation kinetics. The outward currents showed activation thresholds between -20 to -30 mV and slow inactivation. The ionic channels underlying the macroscopic current were highly selective for K(+). Their selectivity was for typical K(+) channels with relative permeabilities of K(+)>NH4+>Cs(+)>Na(+). No evidence of any other type of voltage-gated channel was found. The potassium currents ( I(KV)) were blocked reversibly by tetraethylammonium and barium. The IC(50) value and Hill coefficient of tetraethylammonium inhibition of I(KV) were 0.56 m M and 1.17 respectively. These results demonstrate that human adipose cells have voltage-dependent potassium currents.

Insulin increases the density of potassium channels in white adipocytes: possible role in adipogenesis.

We studied the potassium currents in white adipocytes obtained by culturing preadipocytes from rat epididymal tissue, both with insulin (WA(i)) and without insulin (WA(o)), in order to test the role of insulin in the development of voltage-gated potassium channels (K(v)) during adipogenesis. Occasionally, very small potassium currents (I(K,V)) were present in preadipocytes; however these currents were measured in all differentiated cells (adipocytes). WA(i) exhibited greater macroscopic potassium currents than WA(o) with no apparent differences in kinetics or voltage dependence. The current density (pA/ micro m(2)) calculated in WA(i) was higher than in WA(o). Currents were blocked by millimolar concentrations of tetrethylamonium (TEA). The effect of insulin on adipogenesis, both with and without TEA, was analysed. Four days without insulin and three days with insulin were necessary to increase the total number of cells in culture by 2.5-fold. Insulin increased the number of differentiated cells by 73.5%. Cell proliferation and differentiation were inhibited by TEA. Proliferation was affected only by high concentration of TEA. Inhibition of differentiation was dose dependent, with the concentration necessary for half-block similar to the IC(50) values to block potassium channels. These results suggest that insulin increases the density of K(v) and that these channels may be necessary for the normal growth of white adipocytes in culture.

Malaria vectors in Bioko Island (Equatorial Guinea): PCR determination of the members of Anopheles gambiae Giles complex (Diptera: Culicidae) and pyrethroid knockdown resistance (kdr) in An. gambiae sensu stricto.

Anopheles gambiae sensu lato Giles, 1902 and Anophelesfunestus Giles, 1900 are the main malaria vectors on the island of Bioko (Equatorial Guinea). This study was carried out to determine: a) members of the An. gambiae complex that may be present on the island of Bioko and, b) the sensitivity of An. gambiae sensu stricto to pyrethroids. The analysis by PCR detected the presence of An. gambiae s.s. as the major vector of the complex and the "forest chromosomal form" was demonstrated by cytogenetic analysis. The presence of Anopheles melas in the southwest, north and southeast of the island justifies its study as a vector. The molecular characterization of pyrethroid knockdown resistance (kdr) showed that the populations of An. gambiae s.s. were sensitive and no mutations were found. This fact justifies the implementation on a large scale of pyrethroid-impregnated bednets within the framework of the Malaria Control Program of Equatorial Guinea.

Topoisomerase activities and levels in irradiated Chinese hamster AA8 cells and in its radiosensitive mutant EM9.

PURPOSE: To investigate possible variations in topoisomerase (topo) I and II activities and levels after X-ray treatment in the radiation repair proficient AA8 Chinese hamster cell line for comparison with the radiation sensitive mutant EM9. MATERIALS AND METHODS: AA8 and EM9 cells were irradiated with 5 Gy of X-rays and the activities of topoisomerases I and II in nuclear extracts were studied. Immunological detection of both topoisomerases was carried out in order to detect any changes in the expression of these enzymes as a consequence of irradiation. RESULTS: Topoisomerase activities and levels in irradiated EM9 cells were the same as in control non-irradiated cells. In fact, both topo I and topo II activities clearly increased shortly after irradiation in the parental AA8 cells, with a more rapid increase for topo I than for topo II. In the AA8 cells, an increased level of topo I detectable immunologically was only observed at a later time (1 h) after irradiation, while no similar change was detectable for topo II. CONCLUSIONS: While this hypothesis needs further testing, an attractive idea is that DNA topoisomerases might be involved in the cellular response to radiation damage, either through a direct participation in repair mechanisms or indirectly.

Right ventricular bifocal stimulation in the treatment of dilated cardiomyopathy with heart failure.

OBJECTIVE: To describe a new more efficient method of endocardial cardiac stimulation, which produces a narrower QRS without using the coronary sinus or cardiac veins. METHODS: We studied 5 patients with severe dilated cardiomyopathy, chronic atrial fibrillation and AV block, who underwent definitive endocardial pacemaker implantation, with 2 leads, in the RV, one in the apex and the other in the interventricular septum (sub pulmonary), connected, respectively, to ventricular and atrial bicameral pacemaker outputs. Using Doppler echocardiography, we compared, in the same patient, conventional (VVI), high septal ("AAI") and bifocal ("DDT" with AV interval approximately 0) stimulation. RESULTS: The RV bifocal stimulation had the best results with an increase in ejection fraction and cardiac output and reduction in QRS duration, mitral regurgitation and in the left atrium area (p

Noradrenaline modulates the electrical activity of white adipocytes by a cAMP-dependent mechanism.

We studied the effect of the external addition of noradrenaline (NA) on the electrical activity of white adipocytes from rat epididymal tissue. NA modified the active voltage response recorded by the current clamp technique, and decreased the macroscopic membrane potassium currents measured by a whole-cell configuration patch-clamp technique in cells obtained by culturing differentiating preadipocytes. To analyse if cAMP is implicated in the effect of this hormone on potassium conductances, the changes in electrical activity caused by an increase in the intracellular concentration of cAMP were studied using intracellular recording. The addition of forskolin, or NN-dibutyryl cAMP plus 3-isobutyl-1-methylxanthine to the bath reduced active changes in membrane voltage responses to hyperpolarizing and depolarizing pulses. A similar effect was observed when vasoactive intestinal peptide was added to the superfusion chamber. These results suggest that NA could modulate K+ conductances in white adipocytes, mediated by cAMP.

Both bovine and rabbit lymphocytes conditioned with hydrogen peroxide show an adaptive response to radiation damage.

We have carried out experiments to study the possible induction of an adaptive response in cultured bovine and rabbit lymphocytes conditioned with subtoxic doses of hydrogen peroxide after stimulation and subsequently challenged with 1 Gy of X-rays. Peroxide treatment was given at different doses 48 h after the addition of PHA to stimulate the cells. A protective effect of pre-exposure to H2O2 against radiation damage detected as micronuclei in binucleated cells was evident for all the animals tested regardless the dose of H2O2 used, although this effect was in general of greater magnitude in bovine than in rabbit cells. These results lend further support to our previous finding in human lymphocytes that DNA single strand breaks induced by H2O2 (most likely due to the generation of hydroxyl radicals) is the most important lesion to trigger the adaptive response.

Voltage-dependent potassium channels in white adipocytes.

Macroscopic membrane currents of white adipocytes were studied using the whole-cell variant of the patch-clamp technique. These cells were obtained by differentiating preadipocytes fro rat epididymal tissue. In all differentiated cells outward currents exhibiting sigmoidal activation kinetics were observed with amplitudes ranging from 0.5 to 6 nA. The outward current showed activation thresholds at approximately -25 to -35 mV. The ion channels underlying the macroscopic current were highly selective for K+. Their selectivity was typical for K+ channels, with relative permeabilities of K+ > NH4+ > Cs+, Na+. The potassium current was blocked by tetraethylammonium, 4-aminopyridine, barium and cobalt. These results demonstrate the existence of voltage dependent potassium channels in mature white adipose cells.

Marcapasso endocárdico em recém-nascido / Endocardial pacemakerin small children

Os autores relatam o caso em que uma criança de 48 horas de vida, portadora de bloqueio atrioventricular (BAV) de grau avançado, bradicardia acentuada e insuficiência cardíaca importante foi submetida com sucesso a um implante de marcapasso endocárdico. Como via de acesso foi utilizada a veia jugular interna, o cabo-eletrodo de fixaçäo passiva foi posicionado no ventrículo direito e uma alça foi efetuada no interior do átrio direito. Com o crescimento da criança, observou-se o progressivo desenrolar do cabo-eletrodo. A freqüência inicial do marcapasso com que se obteve melhor débito cardíaco foi de 120 ppm, valor definido através de ecocardiograma bidimensional. Após 28 meses a criança vem apresentando ótima evoluçäo clínica. O marcapasso atualmente demonstra bom funcionamento, tanto no comando como na sensibilidade, e o cabo-eletrodo apresenta desenrolar suave, acompanhando o crescimento da criança.