Radiothérapie « flash » à très haut débit de dose : un moyen d'augmenter l'indice thérapeutique par minimisation des dommages aux tissus sains [Ultrahigh dose-rate, "flash" irradiation minimizes the side-effects of radiotherapy].

PURPOSE: Pencil beam scanning and filter free techniques may involve dose-rates considerably higher than those used in conventional external-beam radiotherapy. Our purpose was to investigate normal tissue and tumour responses in vivo to short pulses of radiation. MATERIAL AND METHODS: C57BL/6J mice were exposed to bilateral thorax irradiation using pulsed (at least 40Gy/s, flash) or conventional dose-rate irradiation (0.03Gy/s or less) in single dose. Immunohistochemical and histological methods were used to compare early radio-induced apoptosis and the development of lung fibrosis in the two situations. The response of two human (HBCx-12A, HEp-2) tumour xenografts in nude mice and one syngeneic, orthotopic lung carcinoma in C57BL/6J mice (TC-1 Luc+), was monitored in both radiation modes. RESULTS: A 17Gy conventional irradiation induced pulmonary fibrosis and activation of the TGF-beta cascade in 100% of the animals 24-36 weeks post-treatment, as expected, whereas no animal developed complications below 23Gy flash irradiation, and a 30Gy flash irradiation was required to induce the same extent of fibrosis as 17Gy conventional irradiation. Cutaneous lesions were also reduced in severity. Flash irradiation protected vascular and bronchial smooth muscle cells as well as epithelial cells of bronchi against acute apoptosis as shown by analysis of caspase-3 activation and TUNEL staining. In contrast, the antitumour effectiveness of flash irradiation was maintained and not different from that of conventional irradiation. CONCLUSION: Flash irradiation shifted by a large factor the threshold dose required to initiate lung fibrosis without loss of the antitumour efficiency, suggesting that the method might be used to advantage to minimize the complications of radiotherapy.

Soldiers in a stingless bee: work rate and task repertoire suggest they are an elite force

The differentiation of workers into morphological subcastes (e.g., soldiers) represents an important evolutionary transition and is thought to improve division of labor in social insects. Soldiers occur in many ant and termite species, where they make up a small proportion of the workforce. A common assumption of worker caste evolution is that soldiers are behavioral specialists. Here, we report the first test of the "rare specialist" hypothesis in a eusocial bee. Colonies of the stingless bee Tetragonisca angustula are defended by a small group of morphologically differentiated soldiers. Contrary to the rare specialist hypothesis, we found that soldiers worked more (+34%-41%) and performed a greater variety of tasks (+23%-34%) than other workers, particularly early in life. Our results suggest a "rare elite" function of soldiers in T. angustula, that is, that they perform a disproportionately large amount of the work. Division of labor was based on a combination of temporal and physical castes, but soldiers transitioned faster from one task to the next. We discuss why the rare specialist assumption might not hold in species with a moderate degree of worker differentiation.

Pedaling rate is an important determinant of human oxygen uptake during exercise on the cycle ergometer.

Estimation of human oxygen uptake (V˙o2) during exercise is often used as an alternative when its direct measurement is not feasible. The American College of Sports Medicine (ACSM) suggests estimating human V˙o2 during exercise on a cycle ergometer through an equation that considers individual's body mass and external work rate, but not pedaling rate (PR). We hypothesized that including PR in the ACSM equation would improve its V˙o2 prediction accuracy. Ten healthy male participants' (age 19-48 years) were recruited and their steady-state V˙o2 was recorded on a cycle ergometer for 16 combinations of external work rates (0, 50, 100, and 150 W) and PR (50, 70, 90, and 110 revolutions per minute). V˙o2 was calculated by means of a new equation, and by the ACSM equation for comparison. Kinematic data were collected by means of an infrared 3-D motion analysis system in order to explore the mechanical determinants of V˙o2. Including PR in the ACSM equation improved the accuracy for prediction of sub-maximal V˙o2 during exercise (mean bias 1.9 vs. 3.3 mL O2 kg(-1) min(-1)) but it did not affect the accuracy for prediction of maximal V˙o2 (P > 0.05). Confirming the validity of this new equation, the results were replicated for data reported in the literature in 51 participants. We conclude that PR is an important determinant of human V˙o2 during cycling exercise, and it should be considered when predicting oxygen consumption.

Measurement of the relative rate of prompt χ c0, χ c1 and χ c2 production at TeV

Prompt production of charmonium χ c0, χ c1 and χ c2 mesons is studied using proton-proton collisions at the LHC at a centre-of-mass energy of TeX TeV. The χ c mesons are identified through their decay to J/ψγ, with J/ψ → μ + μ − using photons that converted in the detector. A data sample, corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb detector, is used to measure the relative prompt production rate of χ c1 and χ c2 in the rapidity range 2.0 < y < 4.5 as a function of the J/ψ transverse momentum from 3 to 20 GeV/c. First evidence for χ c0 meson production at a high-energy hadron collider is also presented.

Heart Rate Variability (HRV) modifications in adult hemiplegic patients after botulinum toxin type A (nt-201) injection.

BACKGROUND: The most important adverse effect of BoNT-A is the systemic diffusion of the toxin. There is some evidence that the administration of high doses can increase the risk of systemic diffusion and the development of clinically evident adverse effects, however an international consensus does not exist about its maximum dose. AIM: The aim of this study was to evaluate changes in autonomic heart drive induced by high doses (higher than 600 units) of incobotulinumtoxinA injection in spastic stroke patients. Moreover, the treatment safety by monitoring adverse events occurrence was assessed. DESIGN: Case control study. POPULATION: Eleven stroke survivors with spastic hemiplegia. METHODS: Patients were treated with intramuscular focal injections of IncobotulinumtoxinA (NT 201; Xeomin®, Merz Pharmaceuticals GmbH, Frankfurt, Germany). Doses were below 12 units/Kg. Each patient underwent an ECG recording before injection and 10 days after treatment. Linear and non-linear Heart Rate variability (HRV) measures were derived from ECGs with a dedicated software. RESULTS: None of the variable considered showed statistically significant changes after BoNT-A injection. CONCLUSION: The use of incobotulinumtoxinA in adult patients at doses up to 12 units/kg seems to be safe regarding autonomic heart drive. CLINICAL REHABILITATION IMPACT: The use of IncobotulinumtoxinA up to 600 units could be a safe therapeutic option in spastic hemiplegic stroke survivors.

Enhancement of viability of radiosensitive (PBMC) and resistant (MDA-MB-231) clones in low-dose-rate cobalt-60 radiation therapy

AbstractObjective:In the present study, the authors investigated the in vitrobehavior of radio-resistant breast adenocarcinoma (MDA-MB-231) cells line and radiosensitive peripheral blood mononuclear cells (PBMC), as a function of different radiation doses, dose rates and postirradiation time kinetics, with a view to the interest of clinical radiotherapy.Materials and Methods:The cells were irradiated with Co-60, at 2 and 10 Gy and two different exposure rates, 339.56 cGy.min–1 and the other corresponding to one fourth of the standard dose rates, present over a 10-year period of cobalt therapy. Post-irradiation sampling was performed at pre-established kinetics of 24, 48 and 72 hours. The optical density response in viability assay was evaluated and a morphological analysis was performed.Results:Radiosensitive PBMC showed decrease in viability at 2 Gy, and a more significant decrease at 10 Gy for both dose rates. MDAMB- 231 cells presented viability decrease only at higher dose and dose rate. The results showed MDA-MB-231 clone expansion at low dose rate after 48–72 hours post-radiation.Conclusion:Low dose rate shows a possible potential clinical impact involving decrease in management of radio-resistant and radiosensitive tumor cell lines in cobalt therapy for breast cancer.

Low-level laser therapy for the prevention of low salivary flow rate after radiotherapy and chemotherapy in patients with head and neck cancer

Abstract Objective: To determine whether low-level laser therapy can prevent salivary hypofunction after radiotherapy and chemotherapy in head and neck cancer patients. Materials and Methods: We evaluated 23 head and neck cancer patients, of whom 13 received laser therapy and 10 received clinical care only. An InGaAlP laser was used intra-orally (at 660 nm and 40 mW) at a mean dose of 10.0 J/cm2 and extra-orally (at 780 nm and 15 mW) at a mean dose of 3.7 J/cm2, three times per week, on alternate days. Stimulated and unstimulated sialometry tests were performed before the first radiotherapy and chemotherapy sessions (N0) and at 30 days after the end of treatment (N30). Results: At N30, the mean salivary flow rates were significantly higher among the laser therapy patients than among the patients who received clinical care only, in the stimulated and unstimulated sialometry tests (p = 0.0131 and p = 0.0143, respectively). Conclusion: Low-level laser therapy, administered concomitantly with radiotherapy and chemotherapy, appears to mitigate treatment-induced salivary hypofunction in patients with head and neck cancer.

Vasicek interest rate model

Tässä tutkielmassa estimoidaan korkomallin parametrit Maximum likelihood metodilla sekä näytetään kuinka mallintaa lyhyen koron evoluutiota ja korkokäyrän rakennetta.

Ex-Dividend Day Returns when Dividend and Capital Gains are Taxed at the Same Rate

Due to the overwhelming international evidence that stock prices drop by less than the dividend paid on ex-dividend days, the ex-dividend day anomaly is considered a stylized fact. Two main approaches have emerged to explain this empirical regularity: the tax-clientele hypothesis and the microstructure of financial markets. Although the most widely accepted explanation for this fact relies on taxes, the ex-dividend day anomaly has been reported even in countries where neither dividends nor capital gains are taxed. The 2006 tax reform in Spain established the same tax rate for dividends and capital gains. This paper investigates stock returns on ex-dividend days in the Spanish stock market after the 2006 tax reform using a random coefficient model. Contrary to previous research, we do not observe an ex-dividend day anomaly. Unlike previous investigations, which are mostly concerned with suggesting explanations as to why this anomaly has occurred, we are in the somewhat strange position of discussing why this anomaly has not occurred. Our findings are robust across companies and stock dividend yields, thus supporting a tax--based explanation for the ex-dividend day anomaly.

Yield in double cropping system as affected by N fertilization rate with pig slurry in a Catalonia dryland region

Intensive swine production is an important agricultural and economical activity in Europe. The high availability of pig slurry (PS) lead to attractive fertilization strategy to reduce costs, therefore is mainly applied as fertilizer in agricultural systems. The optimization N fertilization in these areas should be taken in into to avoid nitrates losses by lixiviation and to achieve maximum efficiency in crop nutrition. Many studies have shown that PS applications can achieve satisfactory yields in different crops by partially or completely replacing synthetic fertilizers. In addition, for the last years, in Northeast Spain (Catalonia) has been widely extended the double-cropping forage system.

Experimental determination of benzene uptake rate in Tenax TA diffusive samplers

This paper proposes a methodology to predict benzene uptake rate in ambient air, using passive samplers with Tenax TA. Variations in the uptake rate were found to occur as a function of the sampling time; and were greater at the beginning of sampling. An empirical model was obtained and values for uptake rate agree with literature. Concentration prediction errors can be minimized by using sampling times of 4 to 14 days, thus avoiding the influence of excessive uptake rates in the initial days and the influence of back diffusion at the end of the sampling period.

Ecological and Epidemiological Analyses of Multiple Sclerosis Relapse Rate

The underlying cause of many human autoimmune diseases is unknown, but several environmental factors are implicated in triggering the self-destructive immune reactions. Multiple Sclerosis (MS) is a chronic autoimmune disease of the central nervous system, potentially leading to persistent neurological deterioration. The cause of MS is not known, and apart from immunomodulatory treatments there is no cure. In the early phase of the disease, relapsing-remitting MS (RR-MS) is characterized by unpredictable exacerbations of the neurological symptoms called relapses, which can occur at different intervals ranging from 4 weeks to several years. Microbial infections are known to be able to trigger MS relapses, and the patients are instructed to avoid all factors that might increase the risk of infections and to properly use antibiotics as well as to take care of dental hygiene. Among those environmental factors which are known to increase susceptibility to infections, high ambient air inhalable particulate matter levels affect all people within a geographical region. During the period of interest in this thesis, the occurrence of MS relapses could be effectively reduced by injections of interferon, which has immunomodulatory and antiviral properties. In this thesis, ecological and epidemiological analyses were used to study the possible connection between MS relapse occurrence, population level viral infections and air quality factors, as well as the effects of interferon medication. Hospital archive data were collected retrospectively from 1986-2001, a period in time ranging from when interferon medication first became available until just before other disease-modifying MS therapies arrived on the market. The grouped data were studied with logistic regression and intervention analysis, and individual patient data with survival analysis. Interferons proved to be effective in the treatment of MS in this observational study, as the amount of MS exacerbations was lower during interferon use as compared to the time before interferon treatment. A statistically significant temporal relationship between MS relapses and inhalable particular matter (PM₁₀) concentrations was found in this study, which implies that MS patients are affected by the exposure to PM₁₀. Interferon probably protected against the effect of PM₁₀, because a significant increase in the risk of exacerbations was only observed in MS patients without interferon medication following environmental exposure to population level specific viral infections and PM₁₀. Apart from being antiviral, interferon could thus also attenuate the enhancement of immune reactions caused by ambient air PM₁₀. The retrospective approach utilizing carefully constructed hospital records proved to be an economical and reliable source of MS disease information for statistical analyses.