Toward Sharing Brain Images: Differentially Private TOF-MRA Images With Segmentation Labels Using Generative Adversarial Networks

Sharing labeled data is crucial to acquire large datasets for various Deep Learning applications. In medical imaging, this is often not feasible due to privacy regulations. Whereas anonymization would be a solution, standard techniques have been shown to be partially reversible. Here, synthetic data using a Generative Adversarial Network (GAN) with differential privacy guarantees could be a solution to ensure the patient's privacy while maintaining the predictive properties of the data. In this study, we implemented a Wasserstein GAN (WGAN) with and without differential privacy guarantees to generate privacy-preserving labeled Time-of-Flight Magnetic Resonance Angiography (TOF-MRA) image patches for brain vessel segmentation. The synthesized image-label pairs were used to train a U-net which was evaluated in terms of the segmentation performance on real patient images from two different datasets. Additionally, the Fréchet Inception Distance (FID) was calculated between the generated images and the real images to assess their similarity. During the evaluation using the U-Net and the FID, we explored the effect of different levels of privacy which was represented by the parameter ϵ. With stricter privacy guarantees, the segmentation performance and the similarity to the real patient images in terms of FID decreased. Our best segmentation model, trained on synthetic and private data, achieved a Dice Similarity Coefficient (DSC) of 0.75 for ϵ = 7.4 compared to 0.84 for ϵ = ∞ in a brain vessel segmentation paradigm (DSC of 0.69 and 0.88 on the second test set, respectively). We identified a threshold of ϵ <5 for which the performance (DSC <0.61) became unstable and not usable. Our synthesized labeled TOF-MRA images with strict privacy guarantees retained predictive properties necessary for segmenting the brain vessels. Although further research is warranted regarding generalizability to other imaging modalities and performance improvement, our results mark an encouraging first step for privacy-preserving data sharing in medical imaging

Assessing efficacy of different nucleos(t)ide backbones in NNRTI-containing regimens in the Swiss HIV Cohort Study

Background The most recommended NRTI combinations as first-line antiretroviral treatment for HIV-1 infection in resource-rich settings are tenofovir/emtricitabine, abacavir/lamivudine, tenofovir/lamivudine and zidovudine/lamivudine. Efficacy studies of these combinations also considering pill numbers, dosing frequencies and ethnicities are rare. Methods We included patients starting first-line combination ART (cART) with or switching from first-line cART without treatment failure to tenofovir/emtricitabine, abacavir/lamivudine, tenofovir/lamivudine and zidovudine/lamivudine plus efavirenz or nevirapine. Cox proportional hazards regression was used to investigate the effect of the different NRTI combinations on two primary outcomes: virological failure (VF) and emergence of NRTI resistance. Additionally, we performed a pill burden analysis and adjusted the model for pill number and dosing frequency. Results Failure events per treated patient for the four NRTI combinations were as follows: 19/1858 (tenofovir/emtricitabine), 9/387 (abacavir/lamivudine), 11/344 (tenofovir/lamivudine) and 45/1244 (zidovudine/lamivudine). Compared with tenofovir/emtricitabine, abacavir/lamivudine had an adjusted HR for having VF of 2.01 (95% CI 0.86-4.55), tenofovir/lamivudine 2.89 (1.22-6.88) and zidovudine/lamivudine 2.28 (1.01-5.14), whereas for the emergence of NRTI resistance abacavir/lamivudine had an HR of 1.17 (0.11-12.2), tenofovir/lamivudine 11.3 (2.34-55.3) and zidovudine/lamivudine 4.02 (0.78-20.7). Differences among regimens disappeared when models were additionally adjusted for pill burden. However, non-white patients compared with white patients and higher pill number per day were associated with increased risks of VF and emergence of NRTI resistance: HR of non-white ethnicity for VF was 2.85 (1.64-4.96) and for NRTI resistance 3.54 (1.20-10.4); HR of pill burden for VF was 1.41 (1.01-1.96) and for NRTI resistance 1.72 (0.97-3.02). Conclusions Although VF and emergence of resistance was very low in the population studied, tenofovir/emtricitabine appears to be superior to abacavir/lamivudine, tenofovir/lamivudine and zidovudine/lamivudine. However, it is unclear whether these differences are due to the substances as such or to an association of tenofovir/emtricitabine regimens with lower pill burde

Temporal trends, risk factors and outcomes of infections due to extended-spectrum β-lactamase producing Enterobacterales in Swiss solid organ transplant recipients between 2012 and 2018.

The burden of antimicrobial resistance is high in solid organ transplant (SOT) recipients. Among Swiss SOT recipients, we assessed temporal trends of ESBL-producing Enterobacterales (ESBL-E), identified risk factors for ESBL-E, and assessed the impact of resistance on patient outcome. Data from the Swiss Transplant Cohort Study (STCS), a nationwide prospective cohort of SOT-recipients, were analysed. Temporal trends were described for ESBL-detection among Escherichia coli and non-Escherichia coli. In a nested case-control study, cases with ESBL-E infection were 1:1 matched (by time since transplantation, organ transplant, pathogen) to controls infected with non-ESBL-E. Factors associated with resistance and with unfavourable 30-day outcome (death, infection relapse, graft loss) were assessed. From 2012 to 2018, we identified 1'212 infection episodes caused by Enterobacterales in 1'074 patients, thereof 11.4% (138/1'212) caused by ESBL-E. The proportion of ESBL-production among Escherichia coli remained stable over time (p = 0.93) but increased for non-E. coli (p = 0.02) Enterobacterales. In the case-control study (n = 102), antibiotic pre-treatment was independently associated with ESBL-production (aOR = 2.6, 95%-CI: 1.0-6.8, p = 0.046). Unfavourable outcome occurred in 24/51 (47%) cases and 9/51 (18%) controls (p = 0.003). Appropriate empiric antibiotic therapy was the only modifiable factor associated with unfavourable outcome. In Swiss SOT-recipients, proportion of infections with ESBL-producing non-E. coli Enterobacterales increased in recent years. Antibiotic pre-treatment represents a risk factor for ESBL-E. Improving appropriateness of empiric antibiotic treatment might be an important measure to reduce unfavourable outcome, which was observed in almost half of SOT-recipients with ESBL-E infections

Burden and Timeline of Infectious Diseases in the First Year After Solid Organ Transplantation in the Swiss Transplant Cohort Study.

The burden and timeline of posttransplant infections are not comprehensively documented in the current era of immunosuppression and prophylaxis. In this prospective study nested within the Swiss Transplant Cohort Study (STCS), all clinically relevant infections were identified by transplant-infectious diseases physicians in persons receiving solid organ transplant (SOT) between May 2008 and December 2014 with ≥12 months of follow-up. Among 3541 SOT recipients, 2761 (1612 kidney, 577 liver, 286 lung, 213 heart, and 73 kidney-pancreas) had ≥12 months of follow-up; 1520 patients (55%) suffered 3520 infections during the first year posttransplantation. Burden and timelines of clinically relevant infections differed between transplantations. Bacteria were responsible for 2202 infections (63%) prevailing throughout the year, with a predominance of Enterobacteriaceae (54%) as urinary pathogens in heart, lung, and kidney transplant recipients, and as digestive tract pathogens in liver transplant recipients. Enterococcus spp (20%) occurred as urinary tract pathogens in kidney transplant recipients and as digestive tract pathogens in liver transplant recipients, and Pseudomonas aeruginosa (9%) in lung transplant recipients. Among 1039 viral infections, herpesviruses predominated (51%) in kidney, liver, and heart transplant recipients. Among 263 fungal infections, Candida spp (60%) prevailed as digestive tract pathogens in liver transplant recipients. Opportunistic pathogens, including Aspergillus fumigatus (1.4%) and cytomegalovirus (6%), were rare, scattering over 12 months across all SOT recipients. In the current era of immunosuppression and prophylaxis, SOT recipients experience a high burden of infections throughout the first year posttransplantation, with rare opportunistic pathogens and a predominance of bacteria

Preventive Strategies Against Cytomegalovirus and Incidence of alpha-Herpesvirus Infections in Solid Organ Transplant Recipients: A Nationwide Cohort Study

We assessed the impact of antiviral preventive strategies on the incidence of herpes simplex virus (HSV) and varicella-zoster virus (VZV) infections in a nationwide cohort of transplant recipients. Risk factors for the development of HSV or VZV infection were assessed by Cox proportional hazards regression. We included 2781 patients (56% kidney, 20% liver, 10% lung, 7.3% heart, 6.7% others). Overall, 1264 (45%) patients received antiviral prophylaxis (ganciclovir or valganciclovir, n = 1145; acyclovir or valacyclovir, n = 138). Incidence of HSV and VZV infections was 28.9 and 12.1 cases, respectively, per 1000 person-years. Incidence of HSV and VZV infections at 1 year after transplant was 4.6% (95% confidence interval [CI] 3.5-5.8) in patients receiving antiviral prophylaxis versus 12.3% (95% CI 10.7-14) in patients without prophylaxis; this was observed particularly for HSV infections (3% [95% CI 2.2-4] versus 9.8% [95% CI 8.4-11.4], respectively). A lower rate of HSV and VZV infections was also seen in donor or recipient cytomegalovirus-positive patients receiving ganciclovir or valganciclovir prophylaxis compared with a preemptive approach. Female sex (hazard ratio [HR] 1.663, p = 0.001), HSV seropositivity (HR 5.198, p &lt; 0.001), previous episodes of rejection (HR 1.95, p = 0.004), and use of a preemptive approach (HR 2.841, p = 0.017) were significantly associated with a higher risk of HSV infection. Although HSV and VZV infections were common after transplantation, antiviral prophylaxis significantly reduced symptomatic HSV infections

Vitamin D status and risk of infections after liver transplantation in the Swiss Transplant Cohort Study.

Increasing evidence indicates a role of vitamin D in the immune system affecting response to infections. We aimed to characterize the role of vitamin D status, i.e. deficiency [25-OH vitamin D (25-OHD) &lt;50 nmol/l] and no deficiency (25-OHD ≥50 nmol/l) in incident infections after liver transplantation. In 135 liver transplant recipients, blood samples drawn at time of liver transplantation and 6 months afterwards were used to determine 25-OHD levels. Incident infections episodes were prospectively collected within the Swiss Transplant Cohort Study database. Poisson regression was applied to address associations between vitamin D status and incident infections. Vitamin D deficiency was common at time of transplantation and 6 months afterwards without a significant change in median 25-OHD levels. In univariable analyses, vitamin D deficiency was a risk factor for incident infections in the first 6 months post-transplant incidence rate ratio (IRR 1.52, 95% CI 1.08-2.15, P = 0.018) and for bacterial infections occurring after 6 up to 30 months post-transplant (IRR 2.29, 95% CI 1.06-4.94, P = 0.034). These associations were not detectable in multivariable analysis with adjustment for multiple confounders. Efforts to optimize vitamin D supplementation in liver transplant recipients are needed. Our data question the role of vitamin D deficiency in incident infections

Probiotikoen erabilpena antibiotikoekin lotutako beherakoaren prebentziorako

Aurrekariak: Azken hamarkadan heste-mikrobiotak gizakiaren osasunean duen garrantzia eta bere asaldurak ekar ditzakeen osasun-arazoak agerian jarri dira. Honekin batera, gaur egungo gizarteak egiten duen antibiotikoen kontsumoa handia da eta medikamentu hauen erabilerarekin estuki lotuta dagoen albo-ondorioa beherakoa da; izan ere, kasu hauetan beherakoa antibiotikoek heste-mikrobiota asaldatzeagatik gertatzen da. Egoera honen aurrean, probiotikoek antibiotikoekin lotutako beherakoa prebenitzeko gaitasunagatik nabarmendu dira. Helburuak: Probiotikoek antibiotikoekin lotutako beherakoa prebenitzeko duten eraginkortasunaren ebidentzia aztertzea eta beren erabilera egokiaren inguruko liburuxka bat eratzea. Metodologia: Datu-base eta web-orrialde espezializatuetan bilaketa egin ondoren gaiaren inguruko bibliografiaren berrikuspena burutu da. Emaitzak: Probiotikoen eraginkortasuna andui espezifiko, dosi, tratamendu-iraupen, erabilpen-baldintza, biztanleria-talde eta osasun-arazoaren araberakoa da. Probiotiko batzuek, adin ezberdineko pertsonengan antibiotikoekin lotutako beherakoa prebenitzeko eraginkortasuna erakutsi dute. Bai haurrengan bai helduengan, Saccharomyces boulardii eta Lactobacillus rhamnosus GG anduiak eraginkortasun sendoena erakutsi duten probiotikoak izan dira. Ondorioak: Antibiotikoekin lotutako beherakoa prebenitzeko probiotikoek duten eraginkortasuna aztertu duten ikerketa askok beren diseinuan eta jarraitutako metodologian ahultasunak erakutsi dituzte , beraz, etorkizunari begira, ebidentzia sendoagoa lortzeko asmoz, ongi diseinatutako ikerketa gehiago gauzatu beharko dira.Antecedentes: En las últimas décadas se ha dado a conocer la importancia de la microbiota intestinal en la salud humana y las consecuencias que puede causar su alteración. Unido a esto, cabe destacar que la población actual consume una gran cantidad de antibióticos y uno de los efectos secundarios que está muy ligado a su uso es la diarrea. De hecho, en estos casos la diarrea se produce principalmente debido a la alteración que provocan los antibióticos en la microbiota intestinal. En este ámbito, los probióticos han destacado por su capacidad para prevenir la diarrea asociada a los antibióticos. Objetivos: Analizar la evidencia existente acerca de la capacidad de los probióticos para prevenir la diarrea asociada a los antibióticos y crear un folleto que trate sobre la elección y uso correcto de los probióticos. Metodología: Se ha realizado una búsqueda en bases de datos y páginas webs especializadas y con la información encontrada se ha realizado una revisión del tema. Resultados: La efectividad de los probióticos depende de factores como la cepa, la dosis, la duración del tratamiento, las condiciones de uso, el grupo de población y el problema de salud. Algunos probióticos han demostrado ser efectivos para prevenir la diarrea asociada a los antibióticos en distintos grupos de edad. Los probióticos que han demostrado tener una evidencia más fuerte en su eficacia han sido principalmente, Saccharomyces boulardii, y también Lactobacillus rhamnosus GG. Conclusiones: Muchos estudios que han investigado la capacidad que tienen los probióticos para prevenir la diarrea asociada a los antibióticos, han mostrado debilidades tanto en el diseño del estudio como en la metodología que han seguido. Por tanto, de cara al futuro y con propósito de lograr mayor evidencia, se deben realizar más estudios con un mejor diseñoBackground: In the last decades, the importance of the intestinal microbiota in human health and the consequences that its alteration can produce have been known. Moreover, the current population consumes a large amount of antibiotics and one of the side effects of its consumption is that they are closely linked to diarrhea. In fact, in these cases diarrhea occurs mainly due to the alteration in the intestinal microbiota caused by antibiotics. Probiotics have stood out for their ability to prevent antibiotic-associated diarrhea. Objectives: To analyze the evidence about the ability of probiotics to prevent antibiotic-associated diarrhea and to create a magazine that explains their correct selection and use. Metodology: A search in databases and specialized websites has been carried out and then a review of the selected bibliography has been presented. Results: The effectiveness of probiotics depends on different factors such as the specific strain, the dose, the duration of the treatment, the use conditions, the population and the health problem. Some probiotics have shown to be effective in preventing antibiotic-associated diarrhea in different age groups. The probiotics that have shown stronger evidence are Saccharomyces boulardii and Lactobacillus rhamnosus GG strains. Conclusions: Many studies that have investigated the ability of probiotics to prevent antibiotic-associated diarrhea have shown weaknesses in the design of the study and in the methodology they have followed. Therefore, with the purpose of achieving greater evidence, more studies with a better design should be carried out in the future.Graduado o Graduada en Enfermería por la Universidad Pública de NavarraErizaintzan Graduatua Nafarroako Unibertsitate Publikoa

The effects of three different priors for variance parameters in the normal-mean hierarchical model

textMany prior distributions are suggested for variance parameters in the hierarchical model. The “Non-informative” interval of the conjugate inverse-gamma prior might cause problems. I consider three priors – conjugate inverse-gamma, log-normal and truncated normal for the variance parameters and do the numerical analysis on Gelman’s 8-schools data. Then with the posterior draws, I compare the Bayesian credible intervals of parameters using the three priors. I use predictive distributions to do predictions and then discuss the differences of the three priors suggested.Mathematic

Baseline characteristics.

<p>Baseline characteristics.</p