47 research outputs found

    A variational joint segmentation and registration framework for multimodal images

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    Image segmentation and registration are closely related image processing techniques and often required as simultaneous tasks. In this work, we introduce an optimization-based approach to a joint registration and segmentation model for multimodal images deformation. The model combines an active contour variational term with mutual information (MI) smoothing fitting term and solves in this way the difficulties of simultaneously performed segmentation and registration models for multimodal images. This combination takes into account the image structure boundaries and the movement of the objects, leading in this way to a robust dynamic scheme that links the object boundaries information that changes over time. Comparison of our model with state of art shows that our method leads to more consistent registrations and accurate results

    The longitudinal relationship between patient-reported outcomes and clinical characteristics among patients with focal segmental glomerulosclerosis in the nephrotic syndrome study network

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    Background. Understanding the relationship between clinical and patient-reported outcomes (PROs) will help support clinical care and future clinical trial design of novel therapies for focal segmental glomerulosclerosis (FSGS). Methods. FSGS patients ≥8 years of age enrolled in the Nephrotic Syndrome Study Network completed Patient-Reported Outcomes Measurement Information System PRO measures of health-related quality of life (HRQoL) (children: global health, mobility, fatigue, pain interference, depression, anxiety, stress and peer relationships; adults: physical functioning, fatigue, pain interference, sleep impairment, mental health, depression, anxiety and social satisfaction) at baseline and during longitudinal follow-up for a maximum of 5 years. Linear mixed-effects models were used to determine which demographic, clinical and laboratory features were associated with PROs for each of the eight children and eight adults studied. Results. There were 45 children and 114 adult FSGS patients enrolled that had at least one PRO assessment and 519 patient visits. Multivariable analyses among children found that edema was associated with global health (-7.6 points, P ¼ 0.02) and mobility (-4.2, P ¼ 0.02), the number of reported symptoms was associated with worse depression (-2.7 per symptom, P ¼ 0.009) and anxiety (-2.3, P ¼ 0.02) and the number of emergency room (ER) visits in the prior 6 months was associated with worse mobility (-2.8 per visit, P < 0.001) and fatigue (-2.4, P ¼ 0.03). Multivariable analyses among adults found the number of reported symptoms was associated with worse function in all eight PROMIS measures and the number of ER visits was associated with worse fatigue, pain interference, sleep impairment, depression, anxiety and social satisfaction. Laboratory markers of disease severity (i.e. proteinuria, estimated glomerular filtration rate and serum albumin) did not predict PRO in multivariable analyses, with the single exception of complete remission and better pain interference scores among children (þ9.3, P ¼ 0.03). Conclusions. PROs provide important information about HRQoL for persons with FSGS that is not captured solely by the examination of laboratory-based markers of disease. However, it is critical that instruments capture the patient experience and FSGS clinical trials may benefit from a disease-specific instrument more sensitive to within-patient changes

    Health-related quality of life (HRQoL) in cystine compared with non-cystine stone formers

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    Cystinuria is a genetic cause of recurrent kidney stones which may be more recurrent and larger than more common non-cystine stones. They may have a greater impact on health-related quality of life (HRQoL). We measured this impact by surveying HRQoL in patients with stones, comparing non-cystine stone formers (NCSF) to cystine stone formers (CYSF) and both groups to normative values of the US population. We used SF-36v2 via an internet instrument. CYSF patients were recruited via cystinuria-related websites, two patient advocacy groups, and an active endourology practice. NCSF patients were recruited from the same practice and by email. Total n surveyed with scorable data: 214 CYSF and 81 NCSF. The participants included 128 men and 161 women. The group of CYSF were significantly younger (39 vs. 54 years) and suffered longer from kidney stones (255 vs. 136 months). CYSF patients had significantly more episodes of stones than NCSF patients in the last year (N = 108 CYSF, N = 20 NCSF). More frequent stones in the last year and mental comorbidities most often predicted worse scores in the individual HRQoL domains. However, cystine stone composition was a significant predictor of worse scores only for role emotional. Better scores in all SF-36 domains were associated with greater time since the last kidney stone event. Although kidney stones are often transient, kidney stone formers, regardless of stone composition, have a worse HRQoL than the standard US population, which has a normative score of 50, such as general health (41.2 +/- A 12.8), bodily pain (46.5 +/- A 11.8) and mental health (45.1 +/- A 12.6). CYSF are more frequent and severe stone formers compared with NCSF with a resulting greater, direct impact on the HRQoL of CYSF patients. Whether preventive strategies for cystinuria are being properly utilized by practitioners, and which strategies are most effective, should be established

    A matrix-free approach to efficient affine-linear image registration on CPU and GPU

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    This paper presents a generic approach to highly efficient image registration in two and three dimensions. Both monomodal and multimodal registration problems are considered. We focus on the important class of affine-linear transformations in a derivative-based optimization framework. Our main contribution is an explicit formulation of the objective function gradient and Hessian approximation that allows for very efficient, parallel derivative calculation with virtually no memory requirements. The flexible parallelism of our concept allows for direct implementation on various hardware platforms. Derivative calculations are fully matrix free and operate directly on the input data, thereby reducing the auxiliary space requirements from O(n) to O(1). The proposed approach is implemented on multicore CPU and GPU. Our GPU code outperforms a conventional matrix-based CPU implementation by more than two orders of magnitude, thus enabling usage in real-time scenarios. The computational properties of our approach are extensively evaluated, thereby demonstrating the performance gain for a variety of real-life medical applications

    Effect of increasing doses of cystine-binding thiol drugs on cystine capacity in patients with cystinuria

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    © 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Appropriate dosing of cystine-binding thiol drugs in the management of cystinuria has been based on clinical stone activity. When new stones form, the dose is increased. Currently, there is no method of measuring urinary drug levels to guide the titration of therapy. Increasing cystine capacity, a measure of cystine solubility, has been promoted as a method of judging the effects of therapy. In this study, we gave increasing doses of tiopronin or d-penicillamine, depending on the patients’ own prescriptions, to ten patients with cystinuria and measured cystine excretion and cystine capacity. The doses were 0, 1, 2, 3 g per day, given in two divided doses, and administered in a random order. Going from 0 to 1 g/day led to an increase in cystine capacity from − 39.1 to 130.4 mg/L (P \u3c 0.009) and decreased 24 h cystine excretion from 1003.9 to 834.8 mg/day (P = 0.039). Increasing the doses from 1 to 2 to 3 g/day had no consistent or significant effect to further increase cystine capacity or decrease cystine excretion. Whether doses higher than 1 g/day have additional clinical benefit is not clear from this study. Limiting doses might be associated with fewer adverse effects without sacrificing the benefit of higher doses if higher doses do not offer clinical importance. However, trials with stone activity as an outcome would be desirable

    Effects of laparoscopic adjustable gastric banding on sleep and metabolism: a 12-month follow-up study

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    Ana C Krieger,1 Heekoung Youn,2 Frank Modersitzki,2 Ya-Lin Chiu,1 Linda M Gerber,1 Elizabeth Weinshel,2 Christine R Fielding21Weill Cornell Medical College and New York Presbyterian Hospital, 2New York University School of Medicine and NYU Langone Medical Center, New York, NYBackground: Obstructive sleep apnea is commonly associated with metabolic changes and obesity, and changes in body weight by either medical or surgical approaches have been considered to affect the severity of sleep apnea and appetite-controlling hormones. This prospective study evaluated the effect of weight loss induced by laparoscopic adjustable gastric banding (LAGB) surgery on respiratory disturbance during sleep, oxygen saturation levels, sleep architecture, and leptin and ghrelin levels.Methods: Participants were patients at a university-based medical center surgical weight loss program. All participants with a body mass index &amp;gt; 30 kg/m2 undergoing LAGB surgery for weight reduction were offered the opportunity to participate in the study. Procedures included overnight polysomnography followed by fasting hormone levels at baseline and 12 months postoperatively.Results: Thirty subjects (10 men, 20 women) of mean age 44.0 &amp;plusmn; 12.5 years were recruited. At 12 months postoperatively, mean excess weight loss was 44.4% &amp;plusmn; 14%. The apnea-hypopnea index decreased from 34.2 &amp;plusmn; 35 to 19.0 &amp;plusmn; 21.7 events per hour (P &amp;lt; 0.0001), while leptin levels decreased from 24.5 &amp;plusmn; 17.42 pg/mL to 11.6 &amp;plusmn; 10.6 pg/mL (P = 0.02). Ghrelin levels did not change substantially. Nadir oxygen saturation levels increased from 81% to 84% at 12 months (P = 0.03). Mean oxygen saturation improved and was positively correlated with ghrelin levels at both time points (r = 0.39, P = 0.07, and r = 0.60, P = 0.01).Conclusion: LAGB surgery was associated with 44.4% excess weight loss at 12 months, accompanied by a 33.7% improvement in apnea-hypopnea index as well as a reduction in leptin levels by 31.7% in this group. An association between ghrelin and mean oxygen saturation was seen and deserves further investigation.Keywords: sleep apnea, obesity, bariatric surgery, weight loss, metabolism, leptin, ghrelin, slee

    Distinguishing four types of Person * Situation interactions: An integrative framework and empirical examination

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    Kuper N, von Garrel AS, Wiernik BM, Phan LV, Modersitzki N, Rauthmann JF. Distinguishing four types of Person * Situation interactions: An integrative framework and empirical examination. Journal of Personality and Social Psychology. 2023.People differ in their reaction to situations, resulting in Person * Situation interactions. These interactions have been emphasized by many theoretical accounts of personality. Nevertheless, empirical progress on Person * Situation interactions has been slow. This is in part attributable to an insufficient distinction of person and situation variables and of different types of interaction effects. We propose a framework distinguishing four nested types of interaction effects varying in specificity: (a) P * S: broad Person * Situation interaction variance, (b) P * Sspec: between-person differences in situation variable-outcome associations, (c) Pspec * S: between-situation differences in person variable-outcome associations, and (d) Pspec * Sspec: specific Person Variable * Situation Variable interactions. We conducted two large online studies (N = 622 and N = 818) with standardized situation stimuli (N = 62 pictures and N = 62 first-person perspective videos) and assessed Big Five traits, DIAMONDS situation characteristics, and Big Five states. Using preregistered multilevel models, we systematically quantified the different interaction types. We found (a) large Person * Situation interaction variance in personality states, (b) sizable individual differences in situation characteristic-state contingencies, (c) consistent but smaller between-situation differences in trait-state associations, and (d) some significant but (very) small Personality Trait * Situation Characteristic interactions. Our findings highlight Person * Situation interactions as potentially important predictors of psychological states, although the explanation of these interactions through specific person variables remains difficult. Individual differences in the reaction to situations should be incorporated into our models of personality. (PsycInfo Database Record (c) 2023 APA, all rights reserved)
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