Left ventricular outflow tract obstruction with abnormal papillary muscles

AbstractA 65-year-old man with a history of hypertension was admitted to our hospital with fainting and syncope. He had experienced recurrent syncope since 20 years of age. On admission, systolic heart murmur was audible at the apex of the heart. Echocardiography revealed anteriorly displaced papillary muscles (PMs), elongation of the anterior mitral valve leaflet (AML), and systolic anterior motion (SAM) of the AML. Color Doppler imaging showed accelerated flow with a pressure gradient (PG) of 56mmHg at the left ventricular outflow tract (LVOT). Cardiac magnetic resonance imaging revealed mild asymmetric septal hypertrophy and multiple accessory PMs. Cine images clearly demonstrated SAM and LVOT obstruction due to anteriorly displaced PMs. Based on these findings, the patient was diagnosed as having hypertrophic cardiomyopathy and LVOT obstruction due to abnormal PMs. Oral administration of bisoprolol (2.5mg/day) was initiated, because the patient rejected surgical treatment. Follow-up echocardiography revealed a gradual decrease in the LVOT-PG to 24mmHg, and no episodes of fainting or syncope have recurred for 2 years after the initiation of bisoprolol.<Learning objective: Abnormal papillary muscle (PM) is an unusual cause of left ventricular outflow tract (LVOT) obstruction, and cardiac magnetic resonance (CMR) imaging has been reported to be useful for diagnosis of abnormal PM. Abnormal PMs with LVOT obstruction are usually treated by surgical correction, and therefore, reports on medical treatment are limited. We report a case of LVOT obstruction due to abnormal PMs, which was accurately diagnosed by CMR imaging and successfully treated with a beta-blocker.

Strong atomic ordering in Gd-doped GaN

Gd-doped GaN (Ga 1-xGd xN) thin films were grown on a GaN(001) template by radio frequency plasma-assisted molecular beam epitaxy and characterized by means of x-ray diffraction (XRD) and transmission electron microscopy (TEM). Three samples with a different Gd composition were prepared in this study: x = 0.02, 0.05, and 0.08. XRD and TEM results revealed that the low Gd concentration GaN possesses the wurtzite structure. On the other hand, it was found that an ordered phase with a quadruple-periodicity along the [001] direction in the wurtzite structure is formed throughout the film with x = 0.08. We proposed the atomistic model for the superlattice structure observed here. © 2012 American Institute of Physics.Manabu Ishimaru, Kotaro Higashi, Shigehiko Hasegawa, Hajime Asahi, Kazuhisa Sato, and Toyohiko J. Konno, "Strong atomic ordering in Gd-doped GaN", Appl. Phys. Lett. 101, 101912 (2012) https://doi.org/10.1063/1.4751245

Takotsubo cardiomyopathy with marked ST-segment elevation and electrical alternans complicated with hyperglycemic hyperosmolar state

金沢大学医薬保健研究域医学系This is the first report of a case of Takotsubo cardiomyopathy with a hyperglycemic hyperosmolar state (HHS). This case presented with marked ST-segment elevation and electrical alternans, uncommon findings in Takotsubo cardiomyopathy. We believe that hyperosmolarity-induced myocardial dehydration and consequent increase in intracellular calcium concentration may be the mechanism of Takotsubo cardiomyopathy and electrical alternans in HH

Polymorphic ventricular tachycardia in a patient with hypertrophic cardiomyopathy and digitalis intoxication

SummaryWe report the case of a 74-year-old woman who presented with recurrent episodes of polymorphic ventricular tachycardia (PVT) with a normal QT interval due to digitalis intoxication (serum digoxin concentration, 5.0 ng/mL) and severe hyperkalemia (serum potassium level, 8.3 mEq/L). In addition, laboratory data showed elevated levels of blood urea nitrogen (54 mg/dL) and serum creatinine (1.57 mg/dL), suggesting dehydration. She had been treated with a combination of digoxin and eplerenone for atrial fibrillation and heart failure. The PVT resolved after treatment for hyperkalemia. Cardiac magnetic resonance imaging and left ventriculography showed left ventricular hypertrophy predominantly in the apex, suggesting apical hypertrophic cardiomyopathy (HCM). We presume that the presence of HCM was related to the occurrence of PVT in this patient with digitalis intoxication and hyperkalemia.<Learning objective: PVT with a normal QT interval caused by digitalis intoxication with hyperkalemia was observed in a patient with HCM treated with digoxin and eplerenone for atrial fibrillation and heart failure. The presence of HCM may be related to the occurrence of PVT. Combination therapy with digoxin and aldosterone receptor antagonist may predispose severe hyperkalemia, and monitoring of serum digitalis concentration and potassium level should be done strictly.

Impact of functional studies on exome sequence variant interpretation in early-onset cardiac conduction system diseases

Aims The genetic cause of cardiac conduction system disease (CCSD) has not been fully elucidated. Whole-exome sequencing (WES) can detect various genetic variants; however, the identification of pathogenic variants remains a challenge. We aimed to identify pathogenic or likely pathogenic variants in CCSD patients by using WES and 2015 American College of Medical Genetics and Genomics (ACMG) standards and guidelines as well as evaluating the usefulness of functional studies for determining them. Methods and Results We performed WES of 23 probands diagnosed with early-onset (&amp;lt;65 years) CCSD and analyzed 117 genes linked to arrhythmogenic diseases or cardiomyopathies. We focused on rare variants (minor allele frequency &amp;lt; 0.1%) that were absent from population databases. Five probands had protein truncating variants in EMD and LMNA which were classified as “pathogenic” by 2015 ACMG standards and guidelines. To evaluate the functional changes brought about by these variants, we generated a knock-out zebrafish with CRISPR-mediated insertions or deletions of the EMD or LMNA homologs in zebrafish. The mean heart rate and conduction velocities in the CRISPR/Cas9-injected embryos and F2 generation embryos with homozygous deletions were significantly decreased. Twenty-one variants of uncertain significance were identified in 11 probands. Cellular electrophysiological study and in vivo zebrafish cardiac assay showed that 2 variants in KCNH2 and SCN5A, 4 variants in SCN10A, and 1 variant in MYH6 damaged each gene, which resulted in the change of the clinical significance of them from “Uncertain significance” to “Likely pathogenic” in 6 probands. Conclusions Of 23 CCSD probands, we successfully identified pathogenic or likely pathogenic variants in 11 probands (48%). Functional analyses of a cellular electrophysiological study and in vivo zebrafish cardiac assay might be useful for determining the pathogenicity of rare variants in patients with CCSD. SCN10A may be one of the major genes responsible for CCSD. Translational Perspective Whole-exome sequencing (WES) may be helpful in determining the causes of cardiac conduction system disease (CCSD), however, the identification of pathogenic variants remains a challenge. We performed WES of 23 probands diagnosed with early-onset CCSD, and identified 12 pathogenic or likely pathogenic variants in 11 of these probands (48%) according to the 2015 ACMG standards and guidelines. In this context, functional analyses of a cellular electrophysiological study and in vivo zebrafish cardiac assay might be useful for determining the pathogenicity of rare variants, and SCN10A may be one of the major development factors in CCSD

Mental workload during endoscopic sinus surgery is associated with surgeons’ skill levels

IntroductionSurgeons’ mental workload during endoscopic sinus surgery (ESS) has not been fully evaluated. The assessment was challenging due to the great diversity of each patient’s anatomy and the consequence variety of surgical difficulties. In this study, we examined the mental workload of surgeons with various surgical skill levels during ESS under the standardized condition provided by novel-designed 3D sinus models.Materials and methodsForty-seven participants performed a high-fidelity ESS simulation with 3D-printed sinus models. Surgeons’ mental workload was assessed with the national aeronautics and space administration-task load index (NASA-TLX). Associations between the total and subscales score of NASA-TLX and surgical skill index, including the board certification status, the number of experienced ESS cases, and the objective structured assessment of technical skills (OSATS), were analyzed. In addition, 10 registrars repeated the simulation surgery, and their NASA-TLX score was compared before and after the repetitive training.ResultsThe total NASA-TLX score was significantly associated with OSATS score (p = 0.0001). Primary component analysis classified the surgeons’ mental burden into three different categories: (1) the skill-level-dependent factors (temporal demand, effort, and performance), (2) the skill-level-independent factors (mental and physical demand), and (3) frustration. After the repetitive training, the skill-level-dependent factors were alleviated (temporal demand; z = −2.3664, p = 0.0091, effort; z = −2.1704, p = 0.0346, and performance; z = −2.5992, p = 0.0017), the independent factors were increased (mental demand; z = −2.5992, p = 0.0023 and physical demand; z = −2.2509, p = 0.0213), and frustration did not change (p = 0.3625).ConclusionSome of the mental workload during ESS is associated with surgical skill level and alleviated with repetitive training. However, other aspects remain a burden or could worsen even when surgeons have gained surgical experience. Routine assessment of registrars’ mental burdens would be necessary during surgical training to sustain their mental health

Hydrolyzed eggshell membrane immobilized on phosphorylcholine polymer supplies extracellular matrix environment for human dermal fibroblasts

We have found that a water-soluble alkaline-digested form of eggshell membrane (ASESM) can provide an extracellular matrix (ECM) environment for human dermal fibroblast cells (HDF) in vitro. Avian eggshell membrane (ESM) has a fibrous-meshwork structure and has long been utilized as a Chinese medicine for recovery from burn injuries and wounds in Asian countries. Therefore, ESM is expected to provide an excellent natural material for biomedical use. However, such applications have been hampered by the insolubility of ESM proteins. We have used a recently developed artificial cell membrane biointerface, 2-methacryloyloxyethyl phosphorylcholine polymer (PMBN) to immobilize ASESM proteins. The surface shows a fibrous structure under the atomic force microscope, and adhesion of HDF to ASESM is ASESM-dose-dependent. Quantitative mRNA analysis has revealed that the expression of type III collagen, matrix metalloproteinase-2, and decorin mRNAs is more than two-fold higher when HDF come into contact with a lower dose ASESM proteins immobilized on PMBN surface. A particle-exclusion assay with fixed erythrocytes has visualized secreted water-binding molecules around the cells. Thus, HDF seems to possess an ECM environment on the newly designed PMBN-ASESM surface, and future applications of the ASESM-PMBN system for biomedical use should be of great interest

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

Abstract: In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M ⊙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded