bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anorectal manometry in women with urinary stress incontinence
Authors: Kjølhede Preben , Hallböök Olof , Rydén Gunnar , Sjödahl Rune 
Published: December 2010

Objective. The aims of this prospective study were to determine the bowel function and the anal sphincter function in women with urinary stress incontinence by means of anorectal manometry and to look for manometric variables which could predict the development of surgery demanding genital prolapse after Burch colposuspension.Subjects. During 1991–1992 twenty‐one women with urodynamicaiiy proven genuine stress urinary incontinence were consecutively operated upon with the Burch colposuspension. No concomitant prolapse repair surgery was performed. Forty‐four healthy subjects without anorectal disorders were used as controls.Methods. All subjects were investigated with anorectal manometry using a microtransducer catheter. A standardized questionnaire concerning bowel function was answered at interview. The manometry and interview were performed preoperatively and one year after the Burch colposuspension.Results. According to the preoperative questionnaire, fecal incontinence was found in 62%, constipation in 38% and straining at defecation in 71%. There were no significant differences in any of the manometric parameters between the preoperative and the one‐year postoperative assessment. The patients with prolapse operations after the colposuspension (n = 6) had a significanth lower anal squeeze pressure area (p = 0.029) preoperatively compared to the control subjects. The patients without prolapse surgery (n = 15) did not differ in manometric parameters from the control subjects.Conclusion. Bowel dysfunction is common in women with stress urinary incontinence. The women with low anal squeeze pressure area preoperatively are at risk for the development of genital prolapse after Burch colposuspension.
Low‐risk human papillomavirus types 6 and 11 associated with carcinomas of the genital and upper aero‐digestive tract
Authors: Turazza Estela , Lapena Alicia , Sprovieri Osvaldo , Torres César Pires , Gurucharri Carlos , Maciel Alejandra , Lema Baltasar , Grinstein Saul , Kahn Tomas 
Published: December 2010

Background. Human papillomavirus (HPVs) types 6 and 11, are frequently found in non‐malignant anogenital condylomas and laryngeal papillomas. However, in an ongoing epidemiological study in Argentina in which 163 anogenital and aero‐respiratory cancer biopsies were analyzed, several cases infected with low‐risk HPVs could be detected. Methods. Tumor samples were analyzed by Southern blot hybridization, using HPVs 6, 11, 16, 18, 30, 31, 33 and 35 as probes, and polymerase chain reaction (PCR) with type‐specific primers and probes.Results. Four invasive carcinomas containing HPV 6 or 11 could be detected (2.4%) by Southern blot technique. HPV 6 DNA was found in a penile carcinoma, a groin carcinoma, and in a tonsillar carcinoma. One cervical carcinoma harbored HPV 11 DNA. Using HPVs 6, 11, 16, 18 and 33 anticontamination primers and probes in PCR, no additional high‐risk HPV types could be detected in these four cancers.Conclusion. This report shows the presence of low‐risk HPVs (HPV 6 and 11) associated to malignant tumors in a frequency higher than usually observed. The data raise questions about which are the circumstances which may favor low‐risk HPV related oncogenesis.
The pharmacological advantage of prolonged dose rate gemcitabine is restricted to patients with variant alleles of cytidine deaminase c.79A>C
Authors: METHAROM Ekkaphon , GALETTIS Peter , MANNERS Susan , JELINEK Maria , LIAUW Winston , de SOUZA Paul L , HOSKINS Janelle M , LINKS Matthew 
Published: December 2010

AbstractAim:  Controversy exists over the optimal dosing for the nucleoside analogue gemcitabine. A pharmacological advantage is achieved by prolonging infusion times but evidence for a clinical benefit has been conflicting. We hypothesized that polymorphisms in genes involved in gemcitabine accumulation, particularly the cytidine deaminase CDA c.79A>C, may influence the optimal dosing regimen in individual patients.Methods:  DNA was collected from 32 patients participating in a randomized crossover study comparing 30‐min with 100‐min infusions of gemcitabine. The relationships between seven polymorphisms among three genes (CDA, RRM1 and DCK) and (i) gemcitabine triphosphate accumulation; (ii) gemcitabine‐induced toxicity; and (iii) dose delivery were examined for each infusion time and week of administration.Results:  There were trends for increased accumulation of gemcitabine‐triphosphate (GEM‐TP) with the variant alleles of CDA c.79A>C, and RRM1‐37C>A and ‐524T>C but none of these reached statistical significance in a univariate analysis. In a multivariable model there were significant effects of infusion duration and week of administration on GEM‐TP accumulation. There were significant interactions between CDA c.79A>C (P = 0.01) and RRM1‐37C>A (P = 0.019) genotypes, infusion time, and arm. More patients with one or two CDA c.79 variant alleles had doses delays (57 vs 13 %, P = 0.03) and a pharmacological advantage for prolonged infusion after week 1.Conclusion:  It is important to consider both pharmacokinetics and pharmacogenetics in optimizing gemcitabine accumulation. This represents a classical interaction between genes and environment and provides support for the consideration of both CDA genotype and infusion duration in development of an individualized dosing strategy.
An effectiveness trial of cognitive behaviour therapy in a representative sample of outpatients with psychosis
Authors: Farhall John , Freeman Nerelie C. , Shawyer Frances , Trauer Tom 
Published: December 2010

ObjectivesThe efficacy of cognitive behaviour therapies for psychosis (CBTp) has been sufficiently established for its inclusion in some national treatment guidelines. However, treatment efficacy does not guarantee effectiveness in routine practice, where clinician expertise and patient mix may be different. Thus, we evaluated the applicability, acceptability and effectiveness of CBTp when offered routinely in a public mental health service.DesignA prospectively recruited representative sample (N = 94) of patients with psychotic disorders from a geographic catchment area in Melbourne, Australia, was randomized to CBTp or treatment as usual.MethodThe CBTp intervention included psychoeducation, positive symptom, and co‐morbid problem components. Therapists collaboratively negotiated goals with patients and utilized treatment components from a manual. Intention‐to‐treat analyses used data at baseline, 9 months and 18 months.ResultsWorking alliance and client satisfaction measures indicated excellent acceptability. Both groups improved to a similar degree on the Positive And Negative Syndrome Scale, with no advantage for the CBTp group. The most frequent CBTp components implemented were co‐morbid disorders/personal issues and personalized psychoeducation; working with persisting symptoms was the main focus in relatively few sessions.ConclusionsThe lack of advantage for the CBTp group may be due to: the infrequent focus on positive symptoms (the most replicated outcome domain for CBTp); the unselected nature of the patients (rather than those with distressing symptoms or referred by clinicians); or, to insufficient therapist expertise.
Validation of a Chinese achievement goal orientation questionnaire
Authors: Lau Kit‐Ling. , Lee John C. K. 
Published: December 2010

Background. The mixed findings of previous studies on the nature and effects of performance goals have led to a call for re‐examination of the dichotomous framework of achievement goal orientation theory. While the call for a revised achievement goal orientation theory has received considerable discussion in Western studies, it is not clear whether the revised theory can also be applied in other ethnic and cultural contexts.Aims. Our aim was to validate the Chinese version of Elliot and Church's (1007) Goal Orientation Questionnaire and to initially test the revised goal orientation theory in the context of Chinese students in Hong Kong.Sample. A total of 270 Chinese students (137 boys and 133 girls) from a primary and secondary school in Hong Kong participated in Study 1. Study 2 involved a total of 9,440 students (5,420 boys and 4,020 girls) from 10 primary and 18 secondary schools in Hong Kong.Method. Participants in Study 1 completed a Chinese Goal Orientation Questionnaire (CGOQ) measuring three types of goal orientation. Exploratory factor analysis, item–total correlation, and reliability analyses were undertaken to assess the psychometric quality of the CGOQ. In Study 2, confirmatory factor analysis was used to provide further validation for the revised questionnaire. The relationships among different goal orientations and that with students' perceived classroom environment and self‐efficacy were also explored using structural equation modelling.Results. Findings of exploratory factor analysis in Study 1 and confirmatory factor analysis in Study 2 supported the proposed factor structure of the CGOQ. All the subscales in the questionnaire also showed good internal consistency reliabilities. The construct validity of the CGOQ was supported by its significant relationship with criterion measures. While most of the relationships between the three types of goal orientation and the learning‐related variables measured in our study were consistent with the revised goal orientation theory, the positive relationships between performance‐avoidance goals, mastery goals, and perceived classroom environment were different from previous studies.Conclusion. Our findings generally supported the trichotomous framework of the revised goal orientation theory with Chinese students in Hong Kong. Consistent with the revised goal orientation theory, our findings indicated that both mastery and performance‐approach goals had positive impacts on students' learning. However, the positive relationships between performance‐avoidance goals, mastery goals, and perceived classroom environment were contradictory to the conceptualization of performance‐avoidance goals in the revised theory. Cultural and social factors affecting Hong Kong students' goal orientations are discussed.
Fitting the factor analysis model in ℓ1 norm
Authors: Trendafilov Nickolay T. 
Published: December 2010

The well‐known problem of fitting the exploratory factor analysis model is reconsidered where the usual least squares goodness‐of‐fit function is replaced by a more resistant discrepancy measure, based on a smooth approximation of the ℓ1 norm.Fitting the factor analysis model to the sample correlation matrix is a complex matrix optimization problem which requires the structure preservation of the unknown parameters (e.g. positive definiteness). The projected gradient approach is a natural way of solving such data matching problems as especially designed to follow the geometry of the model parameters. Two reparameterizations of the factor analysis model are considered. The approach leads to globally convergent procedures for simultaneous estimation of the factor analysis matrix parameters. Numerical examples illustrate the algorithms and factor analysis solutions.
Real‐time dose computation: GPU‐accelerated source modeling and superposition/convolution
Authors: Jacques Robert , Wong John , Taylor Russell , McNutt Todd 
Published: December 2010

Purpose:To accelerate dose calculation to interactive rates using highly parallel graphics processing units (GPUs).Methods:The authors have extended their prior work in GPU‐accelerated superposition/convolution with a modern dual‐source model and have enhanced performance. The primary source algorithm supports both focused leaf ends and asymmetric rounded leaf ends. The extra‐focal algorithm uses a discretized, isotropic area source and models multileaf collimator leaf height effects. The spectral and attenuation effects of static beam modifiers were integrated into each source's spectral function. The authors introduce the concepts of arc superposition and delta superposition. Arc superposition utilizes separate angular sampling for the total energy released per unit mass (TERMA) and superposition computations to increase accuracy and performance. Delta superposition allows single beamlet changes to be computed efficiently. The authors extended their concept of multi‐resolution superposition to include kernel tilting. Multi‐resolution superposition approximates solid angle ray‐tracing, improving performance and scalability with a minor loss in accuracy. Superposition/convolution was implemented using the inverse cumulative‐cumulative kernel and exact radiological path ray‐tracing. The accuracy analyses were performed using multiple kernel ray samplings, both with and without kernel tilting and multi‐resolution superposition.Results:Source model performance was (data dependent) for a high resolution field using an NVIDIA (Santa Clara, CA) GeForce GTX 280. Computation of the physically correct multispectral TERMA attenuation was improved by a material centric approach, which increased performance by over 80%. Superposition performance was improved by to 0.058 and 0.94 s for and water phantoms; a speed‐up of 101–144× over the highly optimized Pinnacle3 (Philips, Madison, WI) implementation. times were 8.3 and 94 s, respectively, on an AMD (Sunnyvale, CA) Opteron 254 (two cores, 2.8 GHz).Conclusions:The authors have completed a comprehensive, GPU‐accelerated dose engine in order to provide a substantial performance gain over CPU based implementations. Real‐time dose computation is feasible with the accuracy levels of the superposition/convolution algorithm.
Micro‐CT dilatometry measures of molecular collagen hydration using bovine extensor tendon
Authors: Fullerton Gary D. , Amurao Maxwell , Rahal Andres , Cameron Ivan L. 
Published: December 2010

Purpose:This article introduces a new method to study macromolecular hydration using micro‐CT dilatometry. The complexity of hydration dependence on solvent temperature,, ionic charge, ionic activity, and ionic radii are barriers to comprehensive understanding of protein function. The crystalline character of collagen‐tendon suggests that tendon dilatometry may give direct access to measures of molecular tropocollagen solvation response.Methods:The molecular basis of thestoichiometric hydration model (SHM) provides tools to validate bovine tendon as a model to study protein‐solvent shape response by micro‐CT measures of tendon diameter, length, and mass during dehydration. The SHM relates macroscopic properties to molecular properties of water interacting with the surface of collagen molecules. There are marked changes at critical SHM hydration levels , 0.262, and 0.724 g water/g dry weight.Results:Micro‐CT analysis of the length, diameter, and volume combined with gravimetric measures of tendon mass as a function of hydration h(g water/g dry solid) shows asymmetric changes in length, diameter, and density as predicted by SHM. The collagen molecules perturb water properties of polar hydration waters per tripeptide unit or to confirm MDS prediction of elevated hydration density 20%–50% higher than bulk water.Conclusions:Results validate the use of tendon dilatometry amplification factors of as an effective model to investigate protein molecule shape change response to solvent molecules. The tendon model for the first time allows direct study of protein hydration and functional response under physiological conditions.
Automated segmentation of cerebral vasculature with aneurysms in 3DRA and TOF‐MRA using geodesic active regions: An evaluation study
Authors: Bogunović Hrvoje , Pozo José María , Villa‐Uriol María Cruz , Majoie Charles B. L. M. , van den Berg Rene , Gratama van Andel Hugo A. F. , Macho Juan M. , Blasco Jordi , San Román Luis , Frangi Alejandro F. 
Published: December 2010

Purpose:To evaluate the suitability of an improved version of an automatic segmentation method based on geodesic active regions (GAR) for segmenting cerebral vasculature with aneurysms from 3D x‐ray reconstruction angiography (3DRA) and time of flight magnetic resonance angiography (TOF‐MRA) images available in the clinical routine.Methods:Three aspects of the GAR method have been improved: execution time, robustness to variability in imaging protocols, and robustness to variability in image spatial resolutions. The improved GAR was retrospectively evaluated on images from patients containing intracranial aneurysms in the area of the Circle of Willis and imaged with two modalities: 3DRA and TOF‐MRA. Images were obtained from two clinical centers, each using different imaging equipment. Evaluation included qualitative and quantitative analyses of the segmentation results on 20 images from 10 patients. The gold standard was built from 660 cross‐sections (33 per image) of vessels and aneurysms, manually measured by interventional neuroradiologists. GAR has also been compared to an interactive segmentation method: isointensity surface extraction (ISE). In addition, since patients had been imaged with the two modalities, we performed an intermodality agreement analysis with respect to both the manual measurements and each of the two segmentation methods.Results:Both GAR and ISE differed from the gold standard within acceptable limits compared to the imaging resolution. GAR (ISE) had an average accuracy of 0.20 (0.24) mm for 3DRA and 0.27 (0.30) mm for TOF‐MRA, and had a repeatability of 0.05 (0.20) mm. Compared to ISE, GAR had a lower qualitative error in the vessel region and a lower quantitative error in the aneurysm region. The repeatability of GAR was superior to manual measurements and ISE. The intermodality agreement was similar between GAR and the manual measurements.Conclusions:The improved GAR method outperformed ISE qualitatively as well as quantitatively and is suitable for segmenting 3DRA and TOF‐MRA images from clinical routine.
Quantification of near‐field heating during volumetric MR‐HIFU ablation
Authors: Mougenot C. , Köhler M. O. , Enholm J. , Quesson B. , Moonen C. 
Published: December 2010

Purpose:High‐intensity focused ultrasound guided by magnetic resonance imaging has been extensively evaluated during the past decade as a clinical alternative for thermal ablation of tumor tissue. However, the maximal ablation volume is limited by the extensive treatment duration resulting from the small size of the focal point as compared to the average tumor size. Volumetric sonication has been shown to efficiently enlarge the ablated volume per sonication, but remains limited by the temperature increase induced in the skin and fat layers. In this study, multiplane MR thermometry is proposed for monitoring the near‐field temperature rise in order to prevent related unintended thermal damage.Methods:The method was evaluated by performing sonications in the thigh muscle of 11 pigs maintained under general anesthesia. Volumetric ablations were performed by steering the focal point along trajectories consisting of multiple outward‐moving concentric circles. Near‐field heating was characterized with MR temperature maps and thermal dose maps. The results from the MR measurements were compared to simulations.Results:In this study, the measured maximum temperature rise was found to correlate linearly with the surface energy density within the near field of the beam path with a slope of. This simple linear model appears to be almost independent of the trajectory pattern and the sonication depth. The safety limit to avoid lethal damage of the subcutaneous tissues of the porcine thigh was identified to be an absolute temperature of , corresponding to a surface energy density of at 1.2 MHz.Conclusions:A linear relationship can be established to estimate the temperature increase based on the chosen power prior to ablation, thereby providing ana priori safety check for possible excessive near‐field heating using a known surface energy density threshold. This method would also give the clinician the possibility to abort the sonication should excessive near‐field temperature rise be seen before fat layer damage or skin burns are inflicted.
An algorithm for efficient metal artifact reductions in permanent seed implants
Authors: Xu Chen , Verhaegen Frank , Laurendeau Denis , Enger Shirin A. , Beaulieu Luc 
Published: December 2010

Purpose:In permanent seed implants, 60 to more than 100 small metal capsules are inserted in the prostate, creating artifacts in x‐ray computed tomography (CT) imaging. The goal of this work is to develop an automatic method for metal artifact reduction (MAR) from small objects such as brachytherapy seeds for clinical applications.Methods:The approach for MAR is based on the interpolation of missing projections by directly using raw helical CT data (sinogram). First, an initial image is reconstructed from the raw CT data. Then, the metal objects segmented from the reconstructed image are reprojected back into the sinogram space to produce a metal‐only sinogram. The Steger method is used to determine precisely the position and edges of the seed traces in the raw CT data. By combining the use of Steger detection and reprojections, the missing projections are detected and replaced by interpolation of non‐missing neighboring projections.Results:In both phantom experiments and patient studies, the missing projections have been detected successfully and the artifacts caused by metallic objects have been substantially reduced. The performance of the algorithm has been quantified by comparing the uniformity between the uncorrected and the corrected phantom images. The results of the artifact reduction algorithm are indistinguishable from the true background value.Conclusions:An efficient algorithm for MAR in seed brachytherapy was developed. The test results obtained using raw helical CT data for both phantom and clinical cases have demonstrated that the proposed MAR method is capable of accurately detecting and correcting artifacts caused by a large number of very small metal objects (seeds) in sinogram space. This should enable a more accurate use of advanced brachytherapy dose calculations, such as Monte Carlo simulations.
Inverse planning for IMRT with nonuniform beam profiles using total‐variation regularization (TVR)
Authors: Kim Taeho , Zhu Lei , Suh Tae‐Suk , Geneser Sarah , Meng Bowen , Xing Lei 
Published: December 2010

Purpose:Radiation therapy with high dose rate and flattening filter‐free (FFF) beams has the potential advantage of greatly reduced treatment time and out‐of‐field dose. Current inverse planning algorithms are, however, not customized for beams with nonuniform incident profiles and the resultant IMRT plans are often inefficient in delivery. The authors propose a total‐variation regularization (TVR)‐based formalism by taking the inherent shapes of incident beam profiles into account.Methods:A novel TVR‐based inverse planning formalism is established for IMRT with nonuniform beam profiles. The authors introduce a TVR term into the objective function, which encourages piecewise constant fluence in the nonuniform FFF fluence domain. The proposed algorithm is applied to lung and prostate and head and neck cases and its performance is evaluated by comparing the resulting plans to those obtained using a conventional beamlet‐based optimization (BBO).Results:For the prostate case, the authors' algorithm produces acceptable dose distributions with only 21 segments, while the conventional BBO requires 114 segments. For the lung case and the head and neck case, the proposed method generates similar coverage of target volume and sparing of the organs‐at‐risk as compared to BBO, but with a markedly reduced segment number.Conclusions:TVR‐based optimization in nonflat beam domain provides an effective way to maximally leverage the technical capacity of radiation therapy with FFF fields. The technique can generate effective IMRT plans with improved dose delivery efficiency without significant deterioration of the dose distribution.