Impact of recombination on genetic variability within Staphylococcus aureus clonal complexes.

The population structure of Staphylococcus aureus is generally described as highly clonal and is consequently subdivided into several clonal complexes (CCs). Recent data suggested that recombination might occur more frequently within than among CCs. To test this hypothesis as well as to understand how genetic diversity is created in S. aureus, we analyzed a collection of 182 isolates with MLST and five highly variable core adhesion (ADH) genes. As expected the polymorphism of ADH genes was higher than MLST genes. However both categories of genes showed low within CCs diversity with a dominant haplotype and its single nucleotide variants. Several recombination events were detected but none involved intra-CC recombination. This did not confirm the hypothesis of higher recombination within CCs. Nevertheless, molecular analyses of variance indicated that these few recombination events have a significant impact on the genetic diversity within CCs. In addition, although most ADH genes were under purifying selection, signs of positive selection associated with a recombinant group were detected. These data highlight the importance of recombination on the evolution of the highly clonal S. aureus and suggest that recombination when combined with demographic mechanisms as well as selection might favor the rapid creation of new clonal complexes.

Radiothérapie externe accélérée postopératoire des carcinomes épidermoïdes localement évolués de la sphère ORL: étude prospective de phase II [Prospective study of accelerated postoperative radiation therapy in patients with squamous-cell carcinoma of the head and neck]

PURPOSE: To assess the feasibility and efficacy of accelerated postoperative radiation therapy (RT) in patients with squamous-cell carcinoma of the head and neck (SCCHN). PATIENTS AND METHODS: Between December 1997 and July 2001, 68 patients (male to female ratio: 52/16; median age: 60-years (range: 43-81) with pT1-pT4 and/or pN0-pN3 SCCHN (24 oropharynx, 19 oral cavity, 13 hypopharynx, 5 larynx, 3 unknown primary, 2 maxillary sinus, and 2 salivary gland) were included in this prospective study. Postoperative RT was indicated because extracapsular infiltration (ECI) was observed in 20 (29%), positive surgical margins (PSM) in 20 (29%) or both in 23 patients (34%). Treatment consisted of external beam RT 66 Gy in 5 weeks and 3 days. Median follow-up was 15 months. RESULTS: According to CTC 2.0, acute morbidity was acceptable: grade 3 mucositis was observed in 15 (22%) patients, grade 3 dysphagia in 19 (28%) patients, grade 3 skin erythema in 21 (31%) patients with a median weight loss of 3.1 kg (range: 0-16). No grade 4 toxicity was observed. Median time to relapse was 13 months; we observed only three (4%) local and four (6%) regional relapses, whereas eight (12%) patients developed distant metastases without any evidence of locoregional recurrence. The 2 years overall-, disease-free survival, and actuarial locoregional control rates were 85, 73 and 83% respectively. CONCLUSION: The reduction of the overall treatment time using postoperative accelerated RT with weekly concomitant boost (six fractions per week) is feasible with local control rates comparable to that of published data. Acute RT-related morbidity is acceptable.

Dosimetric aspects of a national survey of diagnostic and interventional radiology in Switzerland.

The effective dose delivered to the patient was determined, by modeling, for 257 types of examinations covering the different modalities of diagnostic and interventional radiology. The basic operational dosimetric quantities considered were obtained from the parameters of the examinations on the basis of dosimetric models. These models required a precise characterization of each examination. The operational dosimetric quantities were converted into doses to organs and effective doses using appropriate conversion factors. The determination of the collective effective dose to the Swiss population requires a number of corrections to account for the variability of several parameters: sensitivity of the detection system, age, gender, and build of the patient. The use of various dosimetric models is illustrated in this paper for a limited number of examination types covering the different radiological modalities, for which the established typical effective doses are given. With regard to individual doses, the study indicated that the average effective doses per type of examination can be classified into three levels: (a) the weakly irradiating examinations (less than 0.1 mSv), which represent 78% of the examinations and 4% of the collective dose, (b) the moderately irradiating examinations (between 0.1 mSv and 10 mSv), which represent 21% of the examinations and 72% of the collective dose, (c) the strongly irradiating examinations (more than 10 mSv), which represent 1% of the examinations and 24% of the collective dose.

Waveform inversion of crosshole georadar data: influence of source wavelet variability and the suitability of a single wavelet assumption

Waveform-based tomographic imaging of crosshole georadar data is a powerful method to investigate the shallow subsurface because of its ability to provide images of electrical properties in near-surface environments with unprecedented spatial resolution. A critical issue with waveform inversion is the a priori unknown source signal. Indeed, the estimation of the source pulse is notoriously difficult but essential for the effective application of this method. Here, we explore the viability and robustness of a recently proposed deconvolution-based procedure to estimate the source pulse during waveform inversion of crosshole georadar data, where changes in wavelet shape with location as a result of varying near-field conditions and differences in antenna coupling may be significant. Specifically, we examine whether a single, average estimated source current function can adequately represent the pulses radiated at all transmitter locations during a crosshole georadar survey, or whether a separate source wavelet estimation should be performed for each transmitter gather. Tests with synthetic and field data indicate that remarkably good tomographic reconstructions can be obtained using a single estimated source pulse when moderate to strong variability exists in the true source signal with antenna location. Only in the case of very strong variability in the true source pulse are tomographic reconstructions clearly improved by estimating a different source wavelet for each transmitter location.

Intensity modulated radiation therapy or stereotactic fractionated radiotherapy for infratentorial ependymoma in children: a multicentric study.

This study was to evaluate the treatment dosimetry, efficacy and toxicity of intensity modulated radiation therapy (IMRT) and fractionated stereotactic radiotherapy (FSRT) in the management of infratentorial ependymoma. Between 1999 and 2007, seven children (median age, 3.1 years) with infratentorial ependymoma were planned with either IMRT (3 patients) or SFRT (4 patients), the latter after conventional posterior fossa irradiation. Two children underwent gross total resection. Median prescribed dose was 59.4 Gy (range, 55.8-60). The median follow-up for surviving patients was 4.8 years (range, 1.3-8). IMRT (median dose, 59.4 Gy) and FSRT (median dose, 55.8 Gy) achieved similar optimal target coverage. Percentages of maximum doses delivered to the cochleae (59.5 vs 85.0% Gy; P = 0.05) were significantly inferior with IMRT, when compared to FSRT planning. Percentages of maximum doses administered to the pituitary gland (38.2 vs 20.1%; P = 0.05) and optic chiasm (38.1 vs 14.1%; P = 0.001) were, however, significantly higher with IMRT, when compared to FSRT planning. No recurrences were observed at the last follow-up. The estimated 3-year progression-free survival and overall survival were 87.5 and 100%, respectively. No grade >1 acute toxicity was observed. Two patients presented late adverse events (grade 2 hypoacousia) during follow-up, without cognitive impairment. IMRT or FSRT for infratentorial ependymomas is effective and associated with a tolerable toxicity level. Both treatment techniques were able to capitalize their intrinsic conformal ability to deliver high-dose radiation. Larger series of patients treated with these two modalities will be necessary to more fully evaluate these delivery techniques.

Cannabis and benzodiazepines as determinants of methadone trough plasma concentration variability in maintenance treatment: a transnational study.

PURPOSE: To assess tobacco, alcohol, cannabis and benzodiazepine use in methadone maintenance treatment (MMT) as potential sources of variability in methadone pharmacokinetics. METHODS: Trough plasma (R)- and (S)-methadone concentrations were measured on 77 Australian and 74 Swiss MMT patients with no additional medications other than benzodiazepines. Simple and multiple regression analyses were performed for the primary metric, plasma methadone concentration/dose. RESULTS: Cannabis and methadone dose were significantly associated with lower 24-h plasma (R)- and (S)-methadone concentrations/dose. The models containing these variables explained 14-16% and 17-25% of the variation in (R)- and (S)-methadone concentration/dose, respectively. Analysis of 61 patients using only CYP3A4 metabolised benzodiazepines showed this class to be associated with higher (R)-concentration/dose, which is consistent with a potential competitive inhibition of CYP3A4. CONCLUSION: Cannabis use and higher methadone doses in MMT could in part be a response to-or a cause of-more rapid methadone clearance. The effects of cannabis and benzodiazepines should be controlled for in future studies on methadone pharmacokinetics in MMT.

Comparison of the interobserver variability of 2 different methods of dietary assessment in a geriatric ward: a pilot study.

BACKGROUND: Protein-energy malnutrition is highly prevalent in aged populations. Associated clinical, economic, and social burden is important. A valid screening method that would be robust and precise, but also easy, simple, and rapid to apply, is essential for adequate therapeutic management. OBJECTIVES: To compare the interobserver variability of 2 methods measuring food intake: semiquantitative visual estimations made by nurses versus calorie measurements performed by dieticians on the basis of standardized color digital photographs of servings before and after consumption. DESIGN: Observational monocentric pilot study. SETTING/PARTICIPANTS: A geriatric ward. The meals were randomly chosen from the meal tray. The choice was anonymous with respect to the patients who consumed them. MEASUREMENTS: The test method consisted of the estimation of calorie consumption by dieticians on the basis of standardized color digital photographs of servings before and after consumption. The reference method was based on direct visual estimations of the meals by nurses. Food intake was expressed in the form of a percentage of the serving consumed and calorie intake was then calculated by a dietician based on these percentages. The methods were applied with no previous training of the observers. Analysis of variance was performed to compare their interobserver variability. RESULTS: Of 15 meals consumed and initially examined, 6 were assessed with each method. Servings not consumed at all (0% consumption) or entirely consumed by the patient (100% consumption) were not included in the analysis so as to avoid systematic error. The digital photography method showed higher interobserver variability in calorie intake estimations. The difference between the compared methods was statistically significant (P < .03). CONCLUSIONS: Calorie intake measures for geriatric patients are more concordant when estimated in a semiquantitative way. Digital photography for food intake estimation without previous specific training of dieticians should not be considered as a reference method in geriatric settings, as it shows no advantages in terms of interobserver variability.

Variability in urinary oxalate measurements between six international laboratories.

BACKGROUND: Hyperoxaluria is a major risk factor for kidney stone formation. Although urinary oxalate measurement is part of all basic stone risk assessment, there is no standardized method for this measurement. METHODS: Urine samples from 24-h urine collection covering a broad range of oxalate concentrations were aliquoted and sent, in duplicates, to six blinded international laboratories for oxalate, sodium and creatinine measurement. In a second set of experiments, ten pairs of native urine and urine spiked with 10 mg/L of oxalate were sent for oxalate measurement. Three laboratories used a commercially available oxalate oxidase kit, two laboratories used a high-performance liquid chromatography (HPLC)-based method and one laboratory used both methods. RESULTS: Intra-laboratory reliability for oxalate measurement expressed as intraclass correlation coefficient (ICC) varied between 0.808 [95% confidence interval (CI): 0.427-0.948] and 0.998 (95% CI: 0.994-1.000), with lower values for HPLC-based methods. Acidification of urine samples prior to analysis led to significantly higher oxalate concentrations. ICC for inter-laboratory reliability varied between 0.745 (95% CI: 0.468-0.890) and 0.986 (95% CI: 0.967-0.995). Recovery of the 10 mg/L oxalate-spiked samples varied between 8.7 ± 2.3 and 10.7 ± 0.5 mg/L. Overall, HPLC-based methods showed more variability compared to the oxalate oxidase kit-based methods. CONCLUSIONS: Significant variability was noted in the quantification of urinary oxalate concentration by different laboratories, which may partially explain the differences of hyperoxaluria prevalence reported in the literature. Our data stress the need for a standardization of the method of oxalate measurement.

Cancers du sein : comment associer l'hormonothérapie et la radiothérapie en situation adjuvante ? [How to combine hormonotherapy and radiation treatment in adjuvant breast cancer ?]

L'hormonoradiothérapie concomitante est utilisée depuis plusieurs années en pratique clinique quotidienne dans les cancers localement évolués de la prostate. Le transfert de ce concept en pathologie mammaire a été très peu rapporté dans la littérature, mais semble pourtant licite devant l'hormonodépendance fréquente des cancers du sein et la synergie potentielle de ces deux armes thérapeutiques. En situation adjuvante, deux stratégies sont actuellement utilisées : la prescription d'un inhibiteur de l'aromatase d'emblée ou après un délai plus ou moins long de tamoxifène. En pratique, ces molécules peuvent donc interagir avec la radiothérapie adjuvante. Les études rétrospectives récemment publiées n'ont pas mis en évidence de différence significative sur l'incidence des évènements, notamment locorégionaux, de l'association concomitante ou séquentielle du tamoxifène à la radiothérapie. La toxicité de l'association reste discutable en termes de fibroses sous-cutanée et pulmonaire. Il semble que le tamoxifène aggraverait les séquelles postradiques uniquement chez les patientes prédisposées à souffrir d'effets tardifs de la radiothérapie et identifiées par un test prédictif biologique. La prudence reste donc encore de mise du moins pour ces patientes. Cet article détaille les avantages et les risques de l'utilisation concomitante de la radiothérapie et de l'hormonothérapie adjuvantes des cancers localisés du sein. Combined radiation and hormone therapies have become common clinical practice in recent years for locally-advanced prostate cancers. The use of such concomitant therapy in the treatment of breast disease has been infrequently reported in the literature, but seems justified given the common hormonal dependence of breast cancer and the potential synergistic effect of these two treatment modalities. As adjuvant therapy, two strategies are used in daily clinical practice: upfront aromatase inhibitors or sequentially after a variable delay of tamoxifen. These molecules may, thus, interact with radiotherapy. Retrospectives studies recently published did not show any differences in terms of locoregional recurrences between concurrent or sequential radiohormonotherapy. Lung and skin fibroses due to concurrent treatment are still under debate. Nevertheless, late side effects appeared to be increased by such a treatment, particularly in hypersensitive patients identified at risk by the lymphocyte predictive test. Concurrent radiohormonotherapy should, thus, be delivered cautiously at least for these patients. This article details the potent advantages and risks of concurrent use of adjuvant hormonotherapy and radiotherapy in localized breast cancers.

Correction for heart rate variability during 3D whole heart MR coronary angiography.

PURPOSE: To evaluate the effect of a real-time adaptive trigger delay on image quality to correct for heart rate variability in 3D whole-heart coronary MR angiography (MRA). MATERIALS AND METHODS: Twelve healthy adults underwent 3D whole-heart coronary MRA with and without the use of an adaptive trigger delay. The moment of minimal coronary artery motion was visually determined on a high temporal resolution MRI. Throughout the scan performed without adaptive trigger delay, trigger delay was kept constant, whereas during the scan performed with adaptive trigger delay, trigger delay was continuously updated after each RR-interval using physiological modeling. Signal-to-noise, contrast-to-noise, vessel length, vessel sharpness, and subjective image quality were compared in a blinded manner. RESULTS: Vessel sharpness improved significantly for the middle segment of the right coronary artery (RCA) with the use of the adaptive trigger delay (52.3 +/- 7.1% versus 48.9 +/- 7.9%, P = 0.026). Subjective image quality was significantly better in the middle segments of the RCA and left anterior descending artery (LAD) when the scan was performed with adaptive trigger delay compared to constant trigger delay. CONCLUSION: Our results demonstrate that the use of an adaptive trigger delay to correct for heart rate variability improves image quality mainly in the middle segments of the RCA and LAD.

Safe and effective variability-a criterion for dose individualization.

BACKGROUND: : A primary goal of clinical pharmacology is to understand the factors that determine the dose-effect relationship and to use this knowledge to individualize drug dose. METHODS: : A principle-based criterion is proposed for deciding among alternative individualization methods. RESULTS: : Safe and effective variability defines the maximum acceptable population variability in drug concentration around the population average. CONCLUSIONS: : A decision on whether patient covariates alone are sufficient, or whether therapeutic drug monitoring in combination with target concentration intervention is needed, can be made by comparing the remaining population variability after a particular dosing method with the safe and effective variability.

Long-term Outcome and Late Side Effects in Endometrial Cancer Patients Treated with Surgery and Postoperative Radiation Therapy.

BACKGROUND: We retrospectively reviewed the long-term outcome and late side effects of endometrial cancer (EC) patients treated with different techniques of postoperative radiotherapy (PORT). METHODS: Between 1999 and 2012, 237 patients with EC were treated with PORT. Two-dimensional external beam radiotherapy (2D-EBRT) was used in 69 patients (30 %), three-dimensional EBRT (3D-EBRT) in 51 (21 %), and intensity-modulated RT (IMRT) with helical Tomotherapy in 47 (20 %). All patients received a vaginal brachytherapy (VB) boost. Seventy patients (29 %) received VB alone. RESULTS: After a median of 68 months (range, 6-154) of follow-up, overall survival was 75 % [95 % confidence interval (CI), 69-81], disease-free survival was 72 % (95% CI, 66-78), cancer-specific survival was 85 % (95 % CI, 80-89), and locoregional control was 86 % (95 % CI, 81-91). The 5-year estimates of grade 3 or more toxicity and second cancer rates were 0 and 7 % (95 % CI, 1-13) for VB alone, 6 % (95 % CI, 1-11) and 0 % for IMRT + VB, 9 % (95 % CI, 1-17) and 5 % (95 % CI, 1-9) for 3D-EBRT + VB, and 22 % (95 % CI, 12-32) and 12 % (95 % CI, 4-20) for 2D-EBRT + VB (P = 0.002 and P = 0.01), respectively. CONCLUSIONS: Pelvic EBRT should be tailored to patients with high-risk EC because the severe late toxicity observed might outweigh the benefits. When EBRT is prescribed for EC, IMRT should be considered, because it was associated with a significant reduction of severe late side effects.