Aims: Some gene variants in the sodium channels, as well as calcium channels, have been associated with Brugada syndrome (BrS). However, the investigation of the human cellular phenotype and the use ...of drugs for BrS in presence of variant in the calcium channel subunit is still lacking. Objectives: The objective of this study was to establish a cellular model of BrS in the presence of a CACNB2 variant of uncertain significance (c.425C > T/p.S142F) using human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and test drug effects using this model. Methods and results: This study recruited cells from a patient with Brugada syndrome (BrS) and recurrent ventricular fibrillation carrying a missense variant in CACNB2 as well as from three healthy independent persons. These cells (hiPSC-CMs) generated from skin biopsies of healthy persons and the BrS patient (BrS-hiPSC-CMs) as well as CRISPR/Cas9 corrected cells (isogenic control, site-variant corrected) were used for this study. The hiPSC-CMs from the BrS patient showed a significantly reduced L-type calcium channel current (ICa-L) compared with the healthy control hiPSC-CMs. The inactivation curve was shifted to a more positive potential and the recovery from inactivation was accelerated. The protein expression of CACNB2 of the hiPSC-CMs from the BrS-patient was significantly decreased compared with healthy hiPSC-CMs. Moreover, the correction of the CACNB2 site-variant rescued the changes seen in the hiPSC-CMs of the BrS patient to the normal state. These data indicate that the CACNB2 gene variant led to loss-of-function of L-type calcium channels in hiPSC-CMs from the BrS patient. Strikingly, arrhythmia events were more frequently detected in BrS-hiPSC-CMs. Bisoprolol (beta-blockers) at low concentration and quinidine decreased arrhythmic events. Conclusions: The CACNB2 variant (c.425C > T/p.S142F) causes a loss-of-function of L-type calcium channels and is pathogenic for this type of BrS. Bisoprolol and quinidine may be effective for treating BrS with this variant.
Hippocampal-sparing radiotherapy (HSR) is a promising approach to alleviate cognitive side effects following cranial radiotherapy. Microstructural brain changes after irradiation have been ...demonstrated using Diffusion Tensor Imaging (DTI). However, evidence is conflicting for certain parameters and anatomic structures. This study examines the effects of radiation on white matter and hippocampal microstructure using DTI and evaluates whether these may be mitigated using HSR. A total of 35 tumor patients undergoing a prospective randomized controlled trial receiving either conventional or HSR underwent DTI before as well as 6, 12, 18, 24, and 30 (±3) months after radiotherapy. Fractional Anisotropy (FA), Mean Diffusivity (MD), Axial Diffusivity (AD), and Radial Diffusivity (RD) were measured in the hippocampus (CA), temporal, and frontal lobe white matter (TL, FL), and corpus callosum (CC). Longitudinal analysis was performed using linear mixed models. Analysis of the entire patient collective demonstrated an overall FACC decrease and RDCC increase compared to baseline in all follow-ups; ADCC decreased after 6 months, and MDCC increased after 12 months (p ≤ 0.001, 0.001, 0.007, 0.018). ADTL decreased after 24 and 30 months (p ≤ 0.004, 0.009). Hippocampal FA increased after 6 and 12 months, driven by a distinct increase in ADCA and MDCA, with RDCA not increasing until 30 months after radiotherapy (p ≤ 0.011, 0.039, 0.005, 0.040, 0.019). Mean radiation dose correlated positively with hippocampal FA (p < 0.001). These findings may indicate complex pathophysiological changes in cerebral microstructures after radiation, insufficiently explained by conventional DTI models. Hippocampal microstructure differed between patients undergoing HSR and conventional cranial radiotherapy after 6 months with a higher ADCA in the HSR subgroup (p ≤ 0.034).
Abstract
Artificial intelligence (AI) algorithms evaluating supine chest radiographs (SCXRs) have remarkably increased in number recently. Since training and validation are often performed on subsets ...of the same overall dataset, external validation is mandatory to reproduce results and reveal potential training errors. We applied a multicohort benchmarking to the publicly accessible (S)CXR analyzing AI algorithm CheXNet, comprising three clinically relevant study cohorts which differ in patient positioning (SCXRs), the applied reference standards (CT-/SCXR-based) and the possibility to also compare algorithm classification with different medical experts’ reading performance. The study cohorts include 1 a cohort, characterized by 563 CXRs acquired in the emergency unit that were evaluated by 9 readers (radiologists and non-radiologists) in terms of 4 common pathologies, 2 a collection of 6,248 SCXRs annotated by radiologists in terms of pneumothorax presence, its size and presence of inserted thoracic tube material which allowed for subgroup and confounding bias analysis and 3 a cohort consisting of 166 patients with SCXRs that were evaluated by radiologists for underlying causes of basal lung opacities, all of those cases having been correlated to a timely acquired computed tomography scan (SCXR and CT within < 90 min). CheXNet non-significantly exceeded the radiology resident (RR) consensus in the detection of suspicious lung nodules (cohort 1, AUC AI/RR: 0.851/0.839,
p
= 0.793) and the radiological readers in the detection of basal pneumonia (cohort 3, AUC AI/reader consensus: 0.825/0.782,
p
= 0.390) and basal pleural effusion (cohort 3, AUC AI/reader consensus: 0.762/0.710,
p
= 0.336) in SCXR, partly with AUC values higher than originally published (“Nodule”: 0.780, “Infiltration”: 0.735, “Effusion”: 0.864). The classifier “Infiltration” turned out to be very dependent on patient positioning (best in CXR, worst in SCXR). The pneumothorax SCXR cohort 2 revealed poor algorithm performance in CXRs without inserted thoracic material and in the detection of small pneumothoraces, which can be explained by a known systematic confounding error in the algorithm training process. The benefit of clinically relevant external validation is demonstrated by the differences in algorithm performance as compared to the original publication. Our multi-cohort benchmarking finally enables the consideration of confounders, different reference standards and patient positioning as well as the AI performance comparison with differentially qualified medical readers.
(1) Background: cervical cancer is one of the leading causes of cancer-related deaths and the fourth most common cancer among women worldwide. Magnetic resonance imaging (MRI) is the modality of ...choice for loco-regional staging of cervical cancer in the primary diagnostic workup beginning with at least stage IB. (2) Methods: we retrospectively analyzed 16 patients with histopathological proven cervical cancer (FIGO IB1−IVA) for the diagnostic accuracy of standard MRI and standard MRI with diffusion-weighted imaging with background body signal suppression (DWIBS) for the correct pre-therapeutic assessment of the definite FIGO category. (3) Results: In 7 out of 32 readings (22%), DWIBS improved diagnostic accuracy. With DWIBS, four (13%) additional readings were assigned the correct major (I−IV) FIGO stages pre-therapeutically. Interobserver reliability of DWIBS was weakest for parametrial infiltration (k = 0.43; CI-95% 0.00−1.00) and perfect for tumor size <2 cm, infiltration of the vaginal lower third, infiltration of adjacent organs and loco-regional nodal metastases (k = 1.000; CI-95% 1.00−1.00). (4) Conclusions: the pre-therapeutic staging of cervical cancer has a high diagnostic accuracy and interobserver reliability when using standard MRI but can be further optimized with the addition of DWIBS sequences when reporting is performed by an experienced radiologist.
Research with experimental stroke models has identified a wide range of therapeutic proteins that can prevent the brain damage caused by this form of acute neurological injury. Despite this, we do ...not yet have safe and effective ways to deliver therapeutic proteins to the injured brain, and this remains a major obstacle for clinical translation. Current targeted strategies typically involve invasive neurosurgery, whereas systemic approaches produce the undesirable outcome of non-specific protein delivery to the entire brain, rather than solely to the injury site. As a potential way to address this, we developed a protein delivery system modeled after the endogenous immune cell response to brain injury. Using ex-vivo-engineered dendritic cells (DCs), we find that these cells can transiently home to brain injury in a rat model of stroke with both temporal and spatial selectivity. We present a standardized method to derive injury-responsive DCs from bone marrow and show that injury targeting is dependent on culture conditions that maintain an immature DC phenotype. Further, we find evidence that when loaded with therapeutic cargo, cultured DCs can suppress initial neuron death caused by an ischemic injury. These results demonstrate a non-invasive method to target ischemic brain injury and may ultimately provide a way to selectively deliver therapeutic compounds to the injured brain.
(1) Background: Early-stage glottic cancer is easily missed on magnetic resonance imaging (MRI). Diffusion-weighted imaging (DWI) may improve diagnostic accuracy. Therefore, our aim was to assess the ...value of adding diffusion-weighted imaging with background body signal suppression (DWIBS) to pre-therapeutic MRI staging. (2) Methods: Two radiologists with 8 and 13 years of experience, blinded to each other's findings, initially interpreted only standard MRI, later DWIBS alone, and afterward, standard MRI + DWIBS in 41 patients with histopathologically proven pT1a laryngeal cancer of the glottis. (3) Results: Detectability rates with standard MRI, DWIBS only, and standard MRI + DWIBS were 68-71%, 63-66%, and 73-76%, respectively. Moreover, interobserver reliability was calculated as good (κ = 0.712), very good (κ = 0.84), and good (κ = 0.69) for standard MRI, DWIBS only, and standard MRI + DWIBS, respectively. (4) Conclusions: Standard MRI, DWIBS alone, and standard MRI + DWIBS showed an encouraging detection rate, as well as distinct interobserver reliability in the diagnosis of early-stage laryngeal cancer when compared to the definitive histopathologic report.
(1) Background: Early-stage glottic cancer is easily missed on magnetic resonance imaging (MRI). Diffusion-weighted imaging (DWI) may improve diagnostic accuracy. Therefore, our aim was to assess the ...value of adding diffusion-weighted imaging with background body signal suppression (DWIBS) to pre-therapeutic MRI staging. (2) Methods: Two radiologists with 8 and 13 years of experience, blinded to each other’s findings, initially interpreted only standard MRI, later DWIBS alone, and afterward, standard MRI + DWIBS in 41 patients with histopathologically proven pT1a laryngeal cancer of the glottis. (3) Results: Detectability rates with standard MRI, DWIBS only, and standard MRI + DWIBS were 68–71%, 63–66%, and 73–76%, respectively. Moreover, interobserver reliability was calculated as good (κ = 0.712), very good (κ = 0.84), and good (κ = 0.69) for standard MRI, DWIBS only, and standard MRI + DWIBS, respectively. (4) Conclusions: Standard MRI, DWIBS alone, and standard MRI + DWIBS showed an encouraging detection rate, as well as distinct interobserver reliability in the diagnosis of early-stage laryngeal cancer when compared to the definitive histopathologic report.
We assessed the value of sonography in predicting intraoperative difficulties for patients undergoing laparoscopic cholecystectomy and in identifying indicators for conversion to conventional ...cholecystectomy.
Upper abdominal sonography was performed (according to a checklist) in 75 consecutive patients before laparoscopic cholecystectomy. Sonographic findings were verified by the surgeon in the operating room.
Conversion from laparoscopic surgery to laparotomy was performed in five patients (6.7%). Of 75 patients, 19 had sonograms revealing gallbladder wall thickening (>4 mm); surgical preparation difficulties in 16 of these patients led to laparotomy in four patients. Sensitivity, specificity, positive predictive value, and accuracy of wall thickening as an indicator of technical difficulties were 66.7%, 94.1%, 84.2%, and 85.3%, respectively. Sensitivity, specificity, positive predictive value, and accuracy of wall thickening as an indicator of surgical conversion were 80.0%, 78.6%, 21.1%, and 78.7%, respectively. Technical difficulties at laparoscopy occurred in all five patients with pericholecystic fluid on sonography (sensitivity, 20.8%; specificity, 100%; positive predictive value, 100%; accuracy, 74.7%) and led to laparotomy in three patients (sensitivity 60.0%, specificity 97.1%, positive predictive value 60%, accuracy 94.7%). The accuracy of sonography for cholecystolithiasis was 100%.
On sonography, gallbladder wall thickening is the most sensitive indicator and pericholecystic fluid is the most specific indicator of technical difficulties during laparoscopic cholecystectomy. Such difficulties may require conversion to laparotomy.
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