An Arrhythmia classification approach via deep learning using single-lead ECG without QRS wave detection

Arrhythmia, a frequently encountered and life-threatening cardiac disorder, can manifest as a transient or isolated event. Traditional automatic arrhythmia detection methods have predominantly relied on QRS-wave signal detection. Contemporary research has focused on the utilization of wearable devices for continuous monitoring of heart rates and rhythms through single-lead electrocardiogram (ECG), which holds the potential to promptly detect arrhythmias. However, in this study, we employed a convolutional neural network (CNN) to classify distinct arrhythmias without QRS wave detection step. The ECG data utilized in this study were sourced from the publicly accessible PhysioNet databases. Taking into account the impact of the duration of ECG signal on accuracy, this study trained one-dimensional CNN models with 5-s and 10-s segments, respectively, and compared their results. In the results, the CNN model exhibited the capability to differentiate between Normal Sinus Rhythm (NSR) and various arrhythmias, including Atrial Fibrillation (AFIB), Atrial Flutter (AFL), Wolff-Parkinson-White syndrome (WPW), Ventricular Fibrillation (VF), Ventricular Tachycardia (VT), Ventricular Flutter (VFL), Mobitz II AV Block (MII), and Sinus Bradycardia (SB). Both 10-s and 5-s ECG segments exhibited comparable results, with an average classification accuracy of 97.31%. It reveals the feasibility of utilizing even shorter 5-s recordings for detecting arrhythmias in everyday scenarios. Detecting arrhythmias with a single lead aligns well with the practicality of wearable devices for daily use, and shorter detection times also align with their clinical utility in emergency situations.

Laser Speckle Contrast Imaging Guides Needling Treatment of Vascular Complications from Dermal Fillers

BACKGROUND

Although laser Doppler imaging (LDI) accurately delineates a hypoperfused area to help target hyaluronidase treatment, laser speckle contrast imaging (LSCI) is more appropriate for assessing microvascular hemodynamics and has greater reproducibility than LDI. This study investigated the use of LSCI in the evaluation and treatment of six patients who developed vascular complications after facial dermal filler injections.

METHODS

The areas of vascular occlusion were accurately defined in real time by LSCI and were more precise than visual inspections or photographic evidence for guiding needling and hyaluronidase treatment.

RESULTS

All patients had achieved satisfactory outcomes as early as Day 2 of treatment and no procedure-related complications were reported after a median follow-up of 9.5 (7-37) days.

CONCLUSION

LSCI accurately and noninvasively delineated vascular occlusions in real time among patients experiencing complications of facial dermal filler injections. Moreover, LSCI was more accurate than visual and photographic evaluations. Clinicians can use LSCI to reliably follow-up therapeutic outcomes after salvage interventions for vascular occlusions.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Structure and function of the human mitochondrial MRS2 channel

The human Mitochondrial RNA Splicing 2 protein (MRS2) has been implicated in Mg2+ transport across mitochondrial inner membranes, thus playing an important role in Mg2+ homeostasis critical for mitochondrial integrity and function. However, the molecular mechanisms underlying its fundamental channel properties such as ion selectivity and regulation remain unclear. Here, we present structural and functional investigation of MRS2. Cryo-electron microscopy structures in various ionic conditions reveal a pentameric channel architecture and the molecular basis of ion permeation and potential regulation mechanisms. Electrophysiological analyses demonstrate that MRS2 is a Ca2+-regulated, non-selective channel permeable to Mg2+, Ca2+, Na+ and K+, which contrasts with its prokaryotic ortholog, CorA, operating as a Mg2+-gated Mg2+ channel. Moreover, a conserved arginine ring within the pore of MRS2 functions to restrict cation movements, likely preventing the channel from collapsing the proton motive force that drives mitochondrial ATP synthesis. Together, our results provide a molecular framework for further understanding MRS2 in mitochondrial function and disease.

Deep convolutional neural network for rib fracture recognition on chest radiographs

Introduction

Rib fractures are a prevalent injury among trauma patients, and accurate and timely diagnosis is crucial to mitigate associated risks. Unfortunately, missed rib fractures are common, leading to heightened morbidity and mortality rates. While more sensitive imaging modalities exist, their practicality is limited due to cost and radiation exposure. Point of care ultrasound offers an alternative but has drawbacks in terms of procedural time and operator expertise. Therefore, this study aims to explore the potential of deep convolutional neural networks (DCNNs) in identifying rib fractures on chest radiographs.

Methods

We assembled a comprehensive retrospective dataset of chest radiographs with formal image reports documenting rib fractures from a single medical center over the last five years. The DCNN models were trained using 2000 region-of-interest (ROI) slices for each category, which included fractured ribs, non-fractured ribs, and background regions. To optimize training of the deep learning models (DLMs), the images were segmented into pixel dimensions of 128 × 128.

Results

The trained DCNN models demonstrated remarkable validation accuracies. Specifically, AlexNet achieved 92.6%, GoogLeNet achieved 92.2%, EfficientNetb3 achieved 92.3%, DenseNet201 achieved 92.4%, and MobileNetV2 achieved 91.2%.

Discussion

By integrating DCNN models capable of rib fracture recognition into clinical decision support systems, the incidence of missed rib fracture diagnoses can be significantly reduced, resulting in tangible decreases in morbidity and mortality rates among trauma patients. This innovative approach holds the potential to revolutionize the diagnosis and treatment of chest trauma, ultimately leading to improved clinical outcomes for individuals affected by these injuries. The utilization of DCNNs in rib fracture detection on chest radiographs addresses the limitations of other imaging modalities, offering a promising and practical solution to improve patient care and management.

Transumbilical Silicone Implants Breast Augmentation (TUSBA)

Transumbilical breast augmentation with pre-filled silicone implants has been performed previously, but technical challenges remain to accommodate more implant options and dissection planes. We aimed to demonstrate the feasibility of transumbilical breast augmentation using various types of pre-filled silicone implants (TUSBA), and its applicability for subglandular, subfascial, dual-plane implantation. In the early stage, TUSBA was primarily performed using endoscope-assisted blunt dissection, and later converted to full endoscopy dissection to achieve better results. Endoscope was used to confirm the pocket and check bleeding for both groups. For endoscope-assisted group, surgical techniques were modified from conventional TUBA. In full endoscopy TUSBA, the entire dissection process was performed under endoscopic monitoring. Preliminary data of patients undergoing TUSBA from June 2016 to April 2021 were retrospectively reviewed. Breast implants with smooth, textured or nanotextured surface properties and round or anatomical shapes were used, with sizes up to 500 mL. Seventy-four patients with mean age 36.4 years (range: 21-55 years) were enrolled in this study. Follow-up ranged from 1 month to 4 years and 6 months (mean: 15.6 months). No excessive postoperative pain in breast or abdomen was reported. Surgery outcomes were aesthetically pleasing in both groups. In the endoscope-assisted group, 3 (4.6%) required major revisional procedures. No revision was required in the full endoscopy group. TUSBA with various types of silicone implants is feasible, and accommodable to all dissection planes. Full endoscopy technique is helpful in reducing the higher complication rate.

Mechanisms of dual modulatory effects of spermine on the mitochondrial calcium uniporter complex

The mitochondrial Ca 2 + uniporter mediates the crucial cellular process of mitochondrial Ca 2 + uptake, which regulates cell bioenergetics, intracellular Ca 2 + signaling, and cell death initiation. The uniporter contains the pore-forming MCU subunit, an EMRE protein that binds to MCU, and the regulatory MICU1 subunit, which can dimerize with MICU1 or MICU2 and under resting cellular [Ca 2 + ] occludes the MCU pore. It has been known for decades that spermine, which is ubiquitously present in animal cells, can enhance mitochondrial Ca 2 + uptake, but the underlying mechanisms remain unclear. Here, we show that spermine exerts dual modulatory effects on the uniporter. In physiological concentrations of spermine, it enhances uniporter activity by breaking the physical interactions between MCU and the MICU1-containing dimers to allow the uniporter to constitutively take up Ca 2 + even in low [Ca 2 + ] conditions. This potentiation effect does not require MICU2 or the EF-hand motifs in MICU1. When [spermine] rises to millimolar levels, it inhibits the uniporter by targeting the pore region in a MICU-independent manner. The MICU1-dependent spermine potentiation mechanism proposed here, along with our previous finding that cardiac mitochondria have very low MICU1, can explain the puzzling observation in the literature that mitochondria in the heart show no response to spermine.

Evidence supporting the MICU1 occlusion mechanism and against the potentiation model in the mitochondrial calcium uniporter complex

The mitochondrial calcium uniporter is a Ca2+ channel that imports cytoplasmic Ca2+ into the mitochondrial matrix to regulate cell bioenergetics, intracellular Ca2+ signaling, and apoptosis. The uniporter contains the pore-forming MCU subunit, an auxiliary EMRE protein, and the regulatory MICU1/MICU2 subunits. Structural and biochemical studies have suggested that MICU1 gates MCU by blocking/unblocking the pore. However, mitoplast patch-clamp experiments argue that MICU1 does not block, but instead potentiates MCU via allosteric mechanisms. Here, we address this direct clash of the proposed MICU1 function. Supporting the MICU1-occlusion mechanism, patch-clamp demonstrates that purified MICU1 strongly suppresses MCU Ca2+ currents, and this inhibition is abolished by mutating the MCU-interacting K126 residue. Moreover, a membrane-depolarization assay shows that MICU1 prevents MCU-mediated Na+ flux into intact mitochondria under Ca2+-free conditions. Examining the observations underlying the potentiation model, we found that MICU1 occlusion was not detected in mitoplasts not because MICU1 cannot block, but because MICU1 dissociates from the uniporter complex. Furthermore, MICU1 depletion reduces uniporter transport not because MICU1 can potentiate MCU, but because EMRE is down-regulated. These results firmly establish the molecular mechanisms underlying the physiologically crucial process of uniporter regulation by MICU1.

The Removal, Excision, Sterilization, and Quarantine (RESQ) Method is a Feasible Alternative Treatment for Cardiac Implantable Electronic Device Infections

Background

Current guidelines recommend that all infected cardiac implantable electronic devices (CIEDs) should be removed. However, financial or anatomical concerns can lead to management of infection with simple debridement, as opposed to complete removal. In this observational study, we report the outcomes of our modified procedure for this real-world dilemma.

Methods and Results

The Quarantine (RESQ) method is characterized as follows: the removal (R) of all non-essential foreign materials, including old sutures and leads; the excision (E) of all non-viable, chronically inflamed, granulation, or scar tissue; the sterilization (S) of the remaining generator; and the quarantine (Q) of a new pocket in the sub-muscular layer for reimplantation. From a review of electronic medical records, 30 patients were selected and divided into three groups according to the intervention used: RESQ (n = 9) in group A, simple debridement (n = 16) in group B, and guideline-recommended replacement (n = 5) in group C. Patient baseline characteristics were similar between the groups. After analyzing the proportion of patients that were free from infection one year following their respective interventions, we found that group A performed better than group B (100% and 31.2% infection-free, respectively, p = 0.001), and was comparable to group C (both 100% infection-free, p = not applicable).

Conclusions

The RESQ method is a feasible and beneficial alternative for selected patients with CIED infections who are unable to receive a generator replacement according to the recommended guideline.

Long-Term Use of Antiperspirant is Associated with a Low Risk of Postoperative Complications in Patients with Axillary Osmidrosis

Purpose

Many patients with axillary osmidrosis (AO) cannot tolerate the local irritation of strong antiperspirants and discontinue AO use within a short time. This study evaluates the effect of long-term antiperspirant use on postoperative complications after osmidrosis surgery.

Patients and Methods

A total of 116 females (66 antiperspirant and 50 non-antiperspirant cases) who underwent osmidrosis surgery were retrospectively reviewed. Postoperative complications were compared between the 2 groups.

Results

Patients with long-term antiperspirant use had a lower risk of full-thickness skin necrosis compared with those who did not use antiperspirants (odds ratio [OR] = 0.048, 95% confidence Interval [CI]: 0.006–0.392, p = 0.005). Patients with antiperspirants use also had a lower risk of moderate-to-severe erythema compared to those without antiperspirants use (moderate vs mild erythema: OR = 0.351, 95% CI: 0.129–0.959, p = 0.041; severe vs mild erythema: OR = 0.161, 95% CI: 0.047–0.550, p = 0.004). Patients who used antiperspirants also had a lower risk of severe skin erosion compared to those who did not use antiperspirants (severe vs mild skin erosion: OR = 0.164, 95% CI: 0.037–0.725, p = 0.017). There was a trend of lower risk in moderate skin erosion in patients with antiperspirant use compared to those without antiperspirant use, but it was not statistically significant (moderate vs mild epidermal damage and peeling: OR = 0.406, 95% CI: 0.158–1.043, p = 0.061).

Conclusion

Postoperative complications in patients with AO who undergo osmidrosis surgery are lower in those with a long-term antiperspirant use compared to patients who did not use antiperspirants.

Efficacy of Dupilumab on Different Phenotypes of Adult with Moderate-to-Severe Atopic Dermatitis in Taiwan: A Real-World Study

To determine phenotype-related dupilumab response in adult patients with atopic dermatitis (AD), this multicenter, retrospective study included 111 adults with moderate-to-severe AD in Taiwan, with median age of 31.5 years (18–87) and 71 (64.0%) males. Patients received dupilumab 300 mg per two to three weeks up to 12 months. We found a significant improvement after 4 and 16 weeks of treatment in all patients for all the assessed scores, including eczema area and severity index (EASI) improvement ≥50% (EASI-50) and 75% (EASI-75), EASI reaching minimal clinically important difference (MCID), and Investigator’s Global Assessment (IGA) improvement ≥2. Importantly, prior to asthma, early AD onset and 3-week drug intervals were significantly associated with a high proportion of EASI-75 at month 12, while prurigo and lichenoid phenotypes were associated with a lower proportion of EASI-75 at month 12. However, the majority of adverse events were mild in severity. In conclusion, our study results identify phenotype-related dupilumab response at month 12 in adults with moderate-to-severe AD, and we suggest that treatment should not be discontinued until reaching a satisfactory clinical response.

Mechanisms and significance of tissue-specific MICU regulation of the mitochondrial calcium uniporter complex

Mitochondrial Ca2+ uptake, mediated by the mitochondrial Ca2+ uniporter, regulates oxidative phosphorylation, apoptosis, and intracellular Ca2+ signaling. Previous studies suggest that non-neuronal uniporters are exclusively regulated by a MICU1-MICU2 heterodimer. Here, we show that skeletal-muscle and kidney uniporters also complex with a MICU1-MICU1 homodimer and that human/mouse cardiac uniporters are largely devoid of MICUs. Cells employ protein-importation machineries to fine-tune the relative abundance of MICU1 homo- and heterodimers and utilize a conserved MICU intersubunit disulfide to protect properly assembled dimers from proteolysis by YME1L1. Using the MICU1 homodimer or removing MICU1 allows mitochondria to more readily take up Ca2+ so that cells can produce more ATP in response to intracellular Ca2+ transients. However, the trade-off is elevated ROS, impaired basal metabolism, and higher susceptibility to death. These results provide mechanistic insights into how tissues can manipulate mitochondrial Ca2+ uptake properties to support their unique physiological functions.

Safety and Efficacy of Submuscular Implantation With Resterilized Cardiac Implantable Electronic Device in Patients With Device Infection: A Retrospective Observational Study in Taiwan

Background

Reuse of cardiac implantable electronic devices (CIEDs) can reduce the cost of using these expensive devices. However, whether resterilized CIEDs will increase the risk of reinfection in patients with previous device infection remains unknown. The aim of the present study is to compare the reinfection rates in patients who had initial CIED infection and underwent reimplantation of resterilized CIEDs or new devices.

Methods

Data from patients with initial CIED infection who received debridement of the infected pocket and underwent reimplantation of new or resterilized CIEDs at MacKay Memorial Hospital, Taipei, Taiwan, between January 2014 and June 2019 were retrospectively analyzed. Patient characteristics, relapse rates of infection, and potential contributing factors to the infection risk were examined.

Results

Twenty-seven patients with initial CIED infection and reimplanted new CIEDs (n = 11) or resterilized CIEDs (n = 16) were included. During the 2-year follow-up, there were 1 (9.1%) and 2 (12.5%) infection relapses in the new and resterilized CIED groups, respectively. No relapse occurred for either group if the lead was completely removed or cut short. The median duration between debridement and device reimplantation in patients with infection relapse vs patients without relapse was 97 vs 4.5 days for all included patients, and 97 vs 2 days and 50.5 vs 5.5 days for the new and resterilized CIED groups, respectively.

Conclusions

Subpectoral reimplanting of resterilized CIEDs in patients with previous device infection is safe and efficacious. With delicate debridement and complete extraction of the leads, the CIED pocket infection relapse risk can be greatly decreased.

Efficacy and safety of pectoralis muscle flap combined rectus abdominis muscle sheath fasciocutaneous flap for reconstruction of sternal infection

Few studies have assessed the efficacy and safety of reconstruction of sternal infection using a pectoralis muscle flap combined with a rectus abdominis muscle (RAM) sheath fasciocutaneous flap. We report here our experience with this procedure to reconstruct the sternal defect in patients (n = 46) with a deep sternal wound infection (DSWI) after cardiac surgery. After wound reconstruction, the proportion of prolonged mechanical ventilation use and intensive care unit (ICU) stay were 17.4% (n = 8) and 21.7% (n = 10), respectively. The 30‐day all‐cause mortality was 15.2%; recurrence rate was 17.4%; postoperative complications were 15.2%; and median hospital stay was 31 (0‐157) days. Multivariate logistic regression analysis revealed that hypertension (β = 21.32, 95%CI 4.955‐37.68, P = .014), drainage‐tube use (β = 0.944, 95%CI 0.273‐1.614, P = .008), and prolonged intensive care unit stay (β = 53.65, 95%CI 31.353‐75.938, P < .001) were significantly correlated with hospital stay. In conclusion, a procedure including surgical debridement, sternal reconstruction with bilateral PM and RAM sheath flap, long‐term antibiotics, and adequate drainage is a beneficial technique in the reconstruction of deep sternal wound infection after cardiac surgery. Duration of drainage tube use may be as an index for a hospital stay or wound healing.

Kimura Disease of the Thigh Treated With Surgical Excision and Dupilumab

ABSTRACT

Kimura disease (KD) is a rare, chronic inflammatory disorder presenting with solitary or multiple masses. Treatment options include surgical excision, corticosteroids, and radiotherapy; however, optimal therapy remains to be established. Moreover, efficacy of a humanized monoclonal antibody, dupilumab (Dupixent), requires to be demonstrated. Here, we present a 36-year-old male patient with an enlarging mass in the left medial thigh and chronic eczema over the abdomen and lower legs. Kimura disease was diagnosed after surgical excision. Postoperative treatment with dupilumab was applied with an initial dose of 600 mg followed by 300 mg every 2 weeks for 8 months. No recurrence of KD was observed in the 1-year follow-up. The eczematous lesions improved greatly. To our knowledge, this is the first report of using dupilumab for treating KD.

Shikonin Induced Program Cell Death through Generation of Reactive Oxygen Species in Renal Cancer Cells

Shikonin mitigated tumor cell proliferation by elevating reactive oxygen species (ROS) levels. Herein, we investigated the effects of shikonin on renal cancer cell (RCC) cell proliferation. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that shikonin dose-dependently reduced the proliferation of Caki-1 and ACHN cells. Shikonin remarkably triggered necrosis and apoptosis in Caki-1 and ACHN cells in proportion to its concentration. Moreover, necrostatin-1 recovered cell viability in the presence of shikonin. Elevated ROS levels and mitochondrial dysfunction were also found in shikonin treatment groups. Pretreatment with N-acetyl cysteine remarkably mitigated shikonin-induced cell death and ROS generation. Western blot analysis revealed that shikonin reduced pro-PARP, pro-caspase-3, and Bcl-2 expression and increased cleavage PARP expression. Enhanced autophagy was also found in the shikonin-treated group as evidenced by acridine orange staining. Moreover, light chain 3B (LC3B)-II accumulation and enhanced p62 expression indicated that autophagy occurred in the shikonin-treated group. LC3B knockdown considerably recovered cell viability in the presence of shikonin. Shikonin treatment elevated p38 activity in a dose-dependent manner. In conclusion, our results revealed that shikonin triggered programmed cell death via the elevation of ROS level and p38 activity in different types of RCC cells. These findings suggested that shikonin may be a potential anti-RCC agent.

Multi-Stage Conversational Passage Retrieval: An Approach to Fusing Term Importance Estimation and Neural Query Rewriting

Conversational search plays a vital role in conversational information seeking. As queries in information seeking dialogues are ambiguous for traditional ad hoc information retrieval (IR) systems due to the coreference and omission resolution problems inherent in natural language dialogue, resolving these ambiguities is crucial. In this article, we tackle conversational passage retrieval, an important component of conversational search, by addressing query ambiguities with query reformulation integrated into a multi-stage ad hoc IR system. Specifically, we propose two conversational query reformulation (CQR) methods: (1) term importance estimation and (2) neural query rewriting. For the former, we expand conversational queries using important terms extracted from the conversational context with frequency-based signals. For the latter, we reformulate conversational queries into natural, stand-alone, human-understandable queries with a pretrained sequence-to-sequence model. Detailed analyses of the two CQR methods are provided quantitatively and qualitatively, explaining their advantages, disadvantages, and distinct behaviors. Moreover, to leverage the strengths of both CQR methods, we propose combining their output with reciprocal rank fusion, yielding state-of-the-art retrieval effectiveness, 30% improvement in terms of NDCG@3 compared to the best submission of Text REtrieval Conference (TREC) Conversational Assistant Track (CAsT) 2019.

Laser Doppler Imaging for Treating Vascular Complications from Procedures Involving Dermal Fillers: Case Series and Literature Review

Vascular occlusion is a rare but severe complication of dermal filler injections. Early treatment of this complication produces better outcomes. Current diagnostic methods for vascular occlusion in the skin are subjective and imprecise; these include capillary refill time, skin color, and reports of pain. This study aimed to assess the use of laser Doppler imaging (LDI) in the evaluation and treatment of vascular complications caused by dermal filler injections. This retrospective study used laser Doppler imaging (LDI) in 13 patients who developed vascular occlusion after facial dermal filler injections, with subsequent follow-up. The precise areas of perfusion observed on LDI were compared with the findings of clinical and photographic evaluation. The results showed that LDI accurately identified areas of vascular occlusion and improved treatment precision among these thirteen patients. The procedure was more precise than visual inspection or photographic evidence. Satisfactory outcomes were achieved for all patients, and no procedure-related complications were reported. Collectively, LDI provides fast, noninvasive, and accurate delineation of areas of vascular occlusion caused by complications of dermal filler injections and avoids several subjective shortcomings of visual and photographic evaluations. Thus, LDI effectively tracks treatment outcomes. However, large-scale studies are required to confirm the present findings.

A Zigzag Flap for Correcting a Nail Deformity Caused by Subungual Schwannoma

Subungual schwannoma is quite rare and often causes nail deformity and difficulty in wearing shoes. Complete tumor excision is the treatment of choice, and we advocate that restoring the nail appearance should be considered at the same time. We present the case of 43-year-old man with a big toe subungual schwannoma. We designed a zigzag incision method to excise the tumor and also corrected nail-bed deformity. The patient had a smooth recovery, and the nail plate regrew with a good appearance.

Cobalt amine complexes and Ru265 interact with the DIME region of the mitochondrial calcium uniporter

We report our investigation into the MCU-inhibitory activity of Co3+ complexes in comparison to Ru265. These compounds reversibly inhibit the MCU with nanomolar potency. Mutagenesis studies and molecular docking simulations suggest that the complexes operate through interactions with the DIME motif of the MCU pore.

Percutaneous Debridement of and Fibrin Glue Injection Into a Pretibial Morel-Lavallée Lesion: A Case Report and Literature Review

ABSTRACT

The Morel-Lavallée lesion (MLL) is a posttraumatic close degloving injury, which is often underdiagnosed at first. Patients with MLLs usually present with tender and enlarging soft tissue swelling with fluctuation, decreased skin sensation, ecchymosis, or even skin necrosis hours to days after the inciting injury. The lesion can lead to intractable morbidity if it remains untreated. There is no consensus regarding the treatment for MLL at present. Here, we report an MLL in the pretibial region of a 43-year-old woman who experienced a low-energy contusion in a motorbike accident. The pretibial lesion was diagnosed using sonography and fine-needle aspiration. We successfully treated the patient by performing percutaneous debridement via a small incision and injections of fibrin after conservative treatment failed. The method we herein propose achieved the goal of open surgical debridement, providing faster recovery and a high degree of patient comfort. We reviewed the available pertinent literature and propose our own treatment protocol with the aim to establish common therapies ofMLL.

The conserved aspartate ring of MCU mediates MICU1 binding and regulation in the mitochondrial calcium uniporter complex

The mitochondrial calcium uniporter is a Ca²⁺ channel that regulates intracellular Ca²⁺ signaling, oxidative phosphorylation, and apoptosis. It contains the pore-forming MCU protein, which possesses a DIME sequence thought to form a Ca²⁺ selectivity filter, and also regulatory EMRE, MICU1, and MICU2 subunits. To properly carry out physiological functions, the uniporter must stay closed in resting conditions, becoming open only when stimulated by intracellular Ca²⁺ signals. This Ca²⁺-dependent activation, known to be mediated by MICU subunits, is not well understood. Here, we demonstrate that the DIME-aspartate mediates a Ca²⁺-modulated electrostatic interaction with MICU1, forming an MICU1 contact interface with a nearby Ser residue at the cytoplasmic entrance of the MCU pore. A mutagenesis screen of MICU1 identifies two highly-conserved Arg residues that might contact the DIME-Asp. Perturbing MCU-MICU1 interactions elicits unregulated, constitutive Ca²⁺ flux into mitochondria. These results indicate that MICU1 confers Ca²⁺-dependent gating of the uniporter by blocking/unblocking MCU.

Electrical recordings of the mitochondrial calcium uniporter in Xenopus oocytes

The mitochondrial calcium uniporter is a Ca²⁺ channel that has been hard to characterize electrophysiologically. Tsai and Tsai establish a method that permits efficient electrophysiological recordings of the human uniporter in Xenopus oocytes and demonstrate characteristic uniporter behaviour.

The mitochondrial calcium uniporter is a multisubunit Ca²⁺ channel that mediates mitochondrial Ca²⁺ uptake, a cellular process crucial for the regulation of oxidative phosphorylation, intracellular Ca²⁺ signaling, and apoptosis. In the last few years, genes encoding uniporter proteins have been identified, but a lack of efficient tools for electrophysiological recordings has hindered quantitative analysis required to determine functional mechanisms of this channel complex. Here, we redirected Ca²⁺-conducting subunits (MCU and EMRE) of the human uniporter to the plasma membrane of Xenopus oocytes. Two-electrode voltage clamp reveals inwardly rectifying Ca²⁺ currents blocked by a potent inhibitor, Ru360 (half maximal inhibitory concentration, ~4 nM), with a divalent cation conductivity of Ca²⁺ > Sr²⁺ > Ba²⁺, Mn²⁺, and Mg²⁺. Patch clamp recordings further reveal macroscopic and single-channel Ca²⁺ currents sensitive to Ru360. These electrical phenomena were abolished by mutations that perturb MCU-EMRE interactions or disrupt a Ca²⁺-binding site in the pore. Altogether, this work establishes a robust method that enables deep mechanistic scrutiny of the uniporter using classical strategies in ion channel electrophysiology.

Modulation of the slow/common gating of CLC channels by intracellular cadmium

Cd²⁺ binding to the CLC channel dimer interface inhibits slow gating by altering subunit interactions.

Members of the CLC family of Cl⁻ channels and transporters are homodimeric integral membrane proteins. Two gating mechanisms control the opening and closing of Cl⁻ channels in this family: fast gating, which regulates opening and closing of the individual pores in each subunit, and slow (or common) gating, which simultaneously controls gating of both subunits. Here, we found that intracellularly applied Cd²⁺ reduces the current of CLC-0 because of its inhibition on the slow gating. We identified CLC-0 residues C229 and H231, located at the intracellular end of the transmembrane domain near the dimer interface, as the Cd²⁺-coordinating residues. The inhibition of the current of CLC-0 by Cd²⁺ was greatly enhanced by mutation of I225W and V490W at the dimer interface. Biochemical experiments revealed that formation of a disulfide bond within this Cd²⁺-binding site is also affected by mutation of I225W and V490W, indicating that these two mutations alter the structure of the Cd²⁺-binding site. Kinetic studies showed that Cd²⁺ inhibition appears to be state dependent, suggesting that structural rearrangements may occur in the CLC dimer interface during Cd²⁺ modulation. Mutations of I290 and I556 of CLC-1, which correspond to I225 and V490 of CLC-0, respectively, have been shown previously to cause malfunction of CLC-1 Cl⁻ channel by altering the common gating. Our experimental results suggest that mutations of the corresponding residues in CLC-0 change the subunit interaction and alter the slow gating of CLC-0. The effect of these mutations on modulations of slow gating of CLC channels by intracellular Cd²⁺ likely depends on their alteration of subunit interactions.

Discovering Finance Keywords via Continuous-Space Language Models

The growing amount of public financial data makes it increasingly important to learn how to discover valuable information for financial decision making. This article proposes an approach to discovering financial keywords from a large number of financial reports. In particular, we apply the continuous bag-of-words (CBOW) model, a well-known continuous-space language model, to the textual information in 10-K financial reports to discover new finance keywords. In order to capture word meanings to better locate financial terms, we also present a novel technique to incorporate syntactic information into the CBOW model. Experimental results on four prediction tasks using the discovered keywords demonstrate that our approach is effective for discovering predictability keywords for post-event volatility, stock volatility, abnormal trading volume, and excess return predictions. We also analyze the discovered keywords that attest to the ability of the proposed method to capture both syntactic and contextual information between words. This shows the success of this method when applied to the field of finance.

Dual functions of a small regulatory subunit in the mitochondrial calcium uniporter complex

Mitochondrial Ca²⁺ uptake, a process crucial for bioenergetics and Ca²⁺ signaling, is catalyzed by the mitochondrial calcium uniporter. The uniporter is a multi-subunit Ca²⁺-activated Ca²⁺ channel, with the Ca²⁺ pore formed by the MCU protein and Ca²⁺-dependent activation mediated by MICU subunits. Recently, a mitochondrial inner membrane protein EMRE was identified as a uniporter subunit absolutely required for Ca²⁺ permeation. However, the molecular mechanism and regulatory purpose of EMRE remain largely unexplored. Here, we determine the transmembrane orientation of EMRE, and show that its known MCU-activating function is mediated by the interaction of transmembrane helices from both proteins. We also reveal a second function of EMRE: to maintain tight MICU regulation of the MCU pore, a role that requires EMRE to bind MICU1 using its conserved C-terminal polyaspartate tail. This dual functionality of EMRE ensures that all transport-competent uniporters are tightly regulated, responding appropriately to a dynamic intracellular Ca²⁺ landscape.

DOI:http://dx.doi.org/10.7554/eLife.15545.001

Like all power plants, mitochondria – the compartments inside our cells that supply energy – must adjust their energy output to match fluctuations in demand. Inside cells, the levels of calcium ions in the cytoplasm often signal such demands. Mitochondria therefore control their calcium ion levels with tightly regulated, membrane-embedded proteins that move calcium ions into and out of the mitochondria. One of these membrane machines, the mitochondrial calcium uniporter (MCU) complex, is a "smart channel" that admits calcium ions into the mitochondria only when their cytoplasmic levels exceed a threshold.

The MCU complex contains four essential proteins: MCU, which forms the pore through which the calcium ions enter the mitochondrion; MICU1 and MICU2, which act as “gatekeepers”, opening the pore only when the cell contains high levels of calcium ions; and EMRE, a small, mysterious protein. Why is EMRE required for the channel's operation, and how does it fit into the four-protein complex?

By comparing EMRE proteins from different species, constructing mutant forms of EMRE, and recording calcium ion transport in mitochondria from cultured human cells, Tsai, Phillips et al. show that EMRE has two key roles. First, it snuggles up against the MCU protein and forms an essential part of the calcium ion-selective pore. Second, it acts as molecular glue to fix the calcium ion-sensing MICU gatekeepers to the pore. These two linked functions ensure that the MCU complex switches on only when the cell contains high levels of calcium ions, preventing the cell becoming catastrophically overloaded with calcium ions and cell death.

Challenges for the future are to purify the MCU complex and reconstitute its ability to transport calcium ions from its component parts. This will help to determine the structure of the channel.

DOI:http://dx.doi.org/10.7554/eLife.15545.002

Functional reconstitution of the mitochondrial Ca2+/H+ antiporter Letm1

The leucine zipper, EF hand–containing transmembrane protein 1 (Letm1) gene encodes a mitochondrial inner membrane protein, whose depletion severely perturbs mitochondrial Ca²⁺ and K⁺ homeostasis. Here we expressed, purified, and reconstituted human Letm1 protein in liposomes. Using Ca²⁺ fluorophore and ⁴⁵Ca²⁺-based assays, we demonstrate directly that Letm1 is a Ca²⁺ transporter, with apparent affinities of cations in the sequence of Ca²⁺ ≈ Mn²⁺ > Gd³⁺ ≈ La³⁺ > Sr²⁺ >> Ba²⁺, Mg²⁺, K⁺, Na⁺. Kinetic analysis yields a Letm1 turnover rate of 2 Ca²⁺/s and a K_m of ∼25 µM. Further experiments show that Letm1 mediates electroneutral 1 Ca²⁺/2 H⁺ antiport. Letm1 is insensitive to ruthenium red, an inhibitor of the mitochondrial calcium uniporter, and CGP-37157, an inhibitor of the mitochondrial Na⁺/Ca²⁺ exchanger. Functional properties of Letm1 described here are remarkably similar to those of the H⁺-dependent Ca²⁺ transport mechanism identified in intact mitochondria.

Sided functions of an arginine-agmatine antiporter oriented in liposomes

The arginine-dependent extreme acid resistance system helps enteric bacteria survive the harsh gastric environment. At the center of this multiprotein system is an arginine-agmatine antiporter, AdiC. To maintain cytoplasmic pH, AdiC imports arginine and exports its decarboxylated product, agmatine, resulting in a net extrusion of one "virtual proton" in each turnover. The random orientation of AdiC in reconstituted liposomes throws up an obstacle to quantifying its transport mechanism. To overcome this problem, we introduced a mutation, S26C, near the substrate-binding site. This mutant exhibits substrate recognition and pH-dependent activity similar to those of the wild-type protein but loses function completely upon reaction with thiol reagents. The membrane-impermeant MTSES reagent can then be used as a cleanly sided inhibitor to silence those S26C-AdiC proteins whose extracellular portion projects from the external side of the liposome. Alternatively, the membrane-permeant MTSEA and membrane-impermeant reducing reagent, TCEP, can be used together to inhibit proteins in the opposite orientation. This approach allows steady-state kinetic analysis of AdiC in a sided fashion. Arginine and agmatine have similar Michaelis-Menten parameters for both sides of the protein, while the extracellular side selects arginine over argininamide, a mimic of the carboxylate-protonated form of arginine, more effectively than does the cytoplasmic side. Moreover, the two sides of AdiC have different pH sensitivities. AdiC activity increases to a plateau at pH 4 as the extracellular side is acidified, while the cytoplasmic side shows an optimal pH of 5.5, with further acidification inhibiting transport. This oriented system allows more precise analysis of AdiC-mediated substrate transport than has been previously available and permits comparison to the situation experienced by the bacterial membrane under acid stress.

[A nurse's experience caring for a patient with breast cancer who had been previously reported dead by her family]

This article describes the author's experience caring for a female with breast cancer who was reported dead by her family four years earlier due to a long-term disappearance. She had been transferred multiple times hospital to hospital due to inability to afford medical care. Data were collected via observations, interviews, and physical assessments. The author identified four primary problems, including impaired tissue integrity, pain, being compelled to abandon treatment due to financial status, desire for familial support, and sense of guilt toward her family. The author used Watson's Caring Theory to build trust with the patient and provided guidance on wound treatment, pain relief, and rebuilding family relationships in order to help restore the patient's identity and financial aid. As a result, the patient was able to transfer to a public hospital where she received free medical assistance and regained hope in her therapy. However, the palliative-care coordinator misinterpreted the referral and, as a result, experienced moral distress. After clarifying and explaining the meaning and importance of the patient referral, the coordinator accepted her and continued care. This case report can provide a reference for nurses caring for patients without personal identity or financial aid. Nurses should be aware of the presence of moral distress in other medical team members. Early recognition and timely management of team members' moral distress is fundamental to providing the best quality of care for patients and their families.

Optimization of the degenerated interfacial ATP binding site improves the function of disease-related mutant cystic fibrosis transmembrane conductance regulator (CFTR) channels

The cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel, an ATP binding cassette (ABC) protein whose defects cause the deadly genetic disease cystic fibrosis (CF), encompasses two nucleotide binding domains (NBD1 and NBD2). Recent studies indicate that in the presence of ATP, the two NBDs coalesce into a dimer, trapping an ATP molecule in each of the two interfacial composite ATP binding sites (site 1 and site 2). Experimental evidence also suggests that CFTR gating is mainly controlled by ATP binding and hydrolysis in site 2, whereas site 1, which harbors several non-canonical substitutions in ATP-interacting motifs, is considered degenerated. The CF-associated mutation G551D, by introducing a bulky and negatively charged side chain into site 2, completely abolishes ATP-induced openings of CFTR. Here, we report a strategy to optimize site 1 for ATP binding by converting two amino acid residues to ABC consensus (i.e. H1348G) or more commonly seen residues in other ABC proteins (i.e. W401Y,W401F). Introducing either one or both of these mutations into G551D-CFTR confers ATP responsiveness for this disease-associated mutant channel. We further showed that the same maneuver also improved the function of WT-CFTR and the most common CF-associated ΔF508 channels, both of which rely on site 2 for gating control. Thus, our results demonstrated that the degenerated site 1 can be rebuilt to complement or support site 2 for CFTR function. Possible approaches for developing CFTR potentiators targeting site 1 will be discussed.

Coronary artery phenotypes in subjects with negative myocardial perfusion imaging and typical angina pectoris

INTRODUCTION

Limited data are available on coronary lesion morphology for patients with false-negative radionuclide findings together with typical angina symptoms.

METHODS

The study group consisted of 25 subjects with a negative pharmacological thallium (Tl)-201 single-photon emission computed tomography perfusion imaging study but typical angina symptoms and coronary artery disease (CAD) confirmed by coronary angiography. The control group included 690 subjects with a positive pharmacological Tl-201 single-photon emission computed tomography study and CAD.

RESULTS

The study group showed a significantly older and higher female ratio than the control group. Significant differences were found between the 2 groups in the presence of current smoking status and hypertension. A noticeably higher percentage of positive metabolic syndrome ratio, number of metabolic syndrome components, high waist-to-hip ratio percentage and high waist circumference percentage in the study group. The study group was noticeably lower in mean numbers of culprit vessel involvement and mean lesion numbers than the control group. There were more individuals with type A classification and a lower proportion of complex stenoses--which contain type B2 and C lesions--in the study group than in the control group. The study group had significantly fewer calcified stenoses and complex morphology stenoses--the latter of which include lesion morphologies with chronic total occlusion, diffuse and calcification--than the control group.

CONCLUSIONS

For the high probability of CAD lesions that requires interventional therapy, patients with negative myocardial scintigraphy but typical angina symptoms would be beneficial to intensive medical treatment and coronary study.

Stable ATP binding mediated by a partial NBD dimer of the CFTR chloride channel

Cystic fibrosis transmembrane conductance regulator (CFTR), a member of the adenosine triphosphate (ATP) binding cassette (ABC) superfamily, is an ATP-gated chloride channel. Like other ABC proteins, CFTR encompasses two nucleotide binding domains (NBDs), NBD1 and NBD2, each accommodating an ATP binding site. It is generally accepted that CFTR's opening-closing cycles, each completed within 1 s, are driven by rapid ATP binding and hydrolysis events in NBD2. Here, by recording CFTR currents in real time with a ligand exchange protocol, we demonstrated that during many of these gating cycles, NBD1 is constantly occupied by a stably bound ATP or 8-N(3)-ATP molecule for tens of seconds. We provided evidence that this tightly bound ATP or 8-N(3)-ATP also interacts with residues in the signature sequence of NBD2, a telltale sign for an event occurring at the NBD1-NBD2 interface. The open state of CFTR has been shown to represent a two-ATP-bound NBD dimer. Our results indicate that upon ATP hydrolysis in NBD2, the channel closes into a "partial NBD dimer" state where the NBD interface remains partially closed, preventing ATP dissociation from NBD1 but allowing the release of hydrolytic products and binding of the next ATP to occur in NBD2. Opening and closing of CFTR can then be coupled to the formation and "partial" separation of the NBD dimer. The tightly bound ATP molecule in NBD1 can occasionally dissociate from the partial dimer state, resulting in a nucleotide-free monomeric state of NBDs. Our data, together with other structural/functional studies of CFTR's NBDs, suggest that this process is poorly reversible, implying that the channel in the partial dimer state or monomeric state enters the open state through different pathways. We therefore proposed a gating model for CFTR with two distinct cycles. The structural and functional significance of our results to other ABC proteins is discussed.

State-dependent modulation of CFTR gating by pyrophosphate

Cystic fibrosis transmembrane conductance regulator (CFTR) is an adenosine triphosphate (ATP)-gated chloride channel. ATP-induced dimerization of CFTR's two nucleotide-binding domains (NBDs) has been shown to reflect the channel open state, whereas hydrolysis of ATP is associated with channel closure. Pyrophosphate (PPi), like nonhydrolytic ATP analogues, is known to lock open the CFTR channel for tens of seconds when applied with ATP. Here, we demonstrate that PPi by itself opens the CFTR channel in a Mg²⁺-dependent manner long after ATP is removed from the cytoplasmic side of excised membrane patches. However, the short-lived open state (τ ∼1.5 s) induced by MgPPi suggests that MgPPi alone does not support a stable NBD dimer configuration. Surprisingly, MgPPi elicits long-lasting opening events (τ ∼30 s) when administrated shortly after the closure of ATP-opened channels. These results indicate the presence of two different closed states (C₁ and C₂) upon channel closure and a state-dependent effect of MgPPi on CFTR gating. The relative amount of channels entering MgPPi-induced long-open bursts during the ATP washout phase decreases over time, indicating a time-dependent dissipation of the closed state (C₂) that can be locked open by MgPPi. The stability of the C₂ state is enhanced when the channel is initially opened by N⁶-phenylethyl-ATP, a high affinity ATP analogue, but attenuated by W401G mutation, which likely weakens ATP binding to NBD1, suggesting that an ATP molecule remains bound to the NBD1 site in the C₂ state. Taking advantage of the slow opening rate of Y1219G-CFTR, we are able to identify a C₂-equivalent state (C₂*), which exists before the channel in the C₁ state is opened by ATP. This closed state responds to MgPPi much more inefficiently than the C₂ state. Finally, we show that MgAMP-PNP exerts its effects on CFTR gating via a similar mechanism as MgPPi. The structural and functional significance of our findings is discussed.

Valproate-induced hyperammonemic encephalopathy treated by hemodialysis

Valproate-induced hyperammonemic encephalopathy is an unusual but serious complication that may occur in people with normal liver-associated enzyme levels, despite normal therapeutic doses and serum levels of valproate. Here, we describe an adolescent girl who had absence seizure and complained about progressive dizziness and general malaise several days after restarting valproate. Then, she presented vomiting and decreased consciousness three weeks after valproate use. Notably, her serum ammonia level was five times the upper limit of normal (184 micrommol/L), with normal liver-associated enzyme and supra-therapeutic valproate level. EEG showed continuous generalized slowing. The tandem mass analysis revealed carnitine deficiency. Consciousness improved after emergent hemodialysis. Ammonia level and EEG also returned to normal. Possible mechanisms, risk factors and the treatments of valproate-induced hyperammonemic encephalopathy are described. Physicians should consider this possibility when consciousness disturbance occurs in patients treated with valproate.