PROTON MODULATIONS ON THE IONIC CURRENTS IN RABBIT ATRIO-VENTRICULAR NODAL CELLS

Modulations of changing the extracellular pH on the electrophysiological activity of isolated rabbit atrio-ventricular (AV) nodal cells were investigated using the two microelectrode voltage-clamp technique. Increasing pH from 7.4 to 9.5 enhanced spontaneous activity. The action potential amplitude and the maximum rate of depolarization were decreased. The action potential duration at 50% repolarization and the cycle length were shortened. The maximum diastolic potential was hyperpolarized. The pH elevation increased the maximum conductances for both the slow inward current and the delayed outward current systems. In contrast, a decline of pH from 7.4 to 5.5 inhibited the activity and the ionic currents. The effects on the action potential parameters were reversed. However, both acidification and alkalinization failed to affect the gating kinetics of the channels. These results suggest that H⁺ would modulate the electrical activity of the AV nodal cells, due not to an alteration of the membrane surface charge, but to a direct protonation of the ionic channels

Rational design of a photoswitchable DNA glue enabling high regulatory function and supramolecular chirality transfer

Short, complementary DNA single strands with mismatched base pairs cannot undergo spontaneous formation of duplex DNA (dsDNA). Mismatch binding ligands (MBLs) can compensate this effect, inducing the formation of the double helix and thereby acting as a molecular glue. Here, we present the rational design of photoswitchable MBLs that allow for reversible dsDNA assembly by light. Careful choice of the azobenzene core structure results in excellent band separation of the E and Z isomers of the involved chromophores. This effect allows for efficient use of light as an external control element for duplex DNA formation and for an in-depth study of the DNA–ligand interaction by UV-Vis, SPR, and CD spectroscopy, revealing a tight mutual interaction and complementarity between the photoswitchable ligand and the mismatched DNA. We also show that the configuration of the switch reversibly dictates the conformation of the DNA strands, while the dsDNA serves as a chiral clamp and translates its chiral information onto the ligand inducing a preference in helical chirality of the Z isomer of the MBLs

A pediatric case of productive cough caused by novel variants in DNAH9

We report the first Japanese case of primary ciliary dyskinesia caused by DNAH9 variations. The patient, a 5-year-old girl, had repeated episodes of productive cough after contracting the common cold at the age of 1 year and 6 months. She did not have a situs abnormality or congenital heart defect. We identified two novel DNAH9 variants, NM_001372.3: c. [1298C>G];[5547_5550delTGAC], (p.[Ser433Cys];[Asp1850fs])

The simultaneous determination of silicic, boric and carbonic acids in natural water via ion-exclusion chromatography with a charged aerosol detector

The simple and simultaneous determination of silicic, boric and carbonic acids was made using ion-exclusion chromatography (IEC) and a Corona™ charged aerosol detector (C-CAD). Silicic and boric acids were separated by the column packed with a weakly acidic cation-exchange resin in H+-form and ultra-pure water eluent, and the detector responses were improved by the addition of acetonitrile to eluent. Under the optimized conditions, the simultaneous determination of weak inorganic acids, except for carbonic acid, was successfully performed. When the conversion column packed with a strong acidic cation-exchange resin in Na+- or K+-form was inserted between the separation column and the detector, weak inorganic acids including carbonic acid could be detected by the C-CAD. The calibration curves were linear in the range of 0.5–10 mg·L−1 as Si for silicic acid (r2 = 0.996), 10–100 mg·L−1 as B for boric acid (r2 = 0.998) and 1.3–21 mg·L−1 as C for carbonic acid (r2 = 0.993). The detection limits based on three times the standard deviation were 0.03 mg·L−1 as Si for silicic acid, 0.40 mg·L−1 as B for boric acid and 0.08 mg·L−1 as C for carbonic acid. This method was applicable to river, hot spring and drinking water

A case of cardiac sarcoidosis masquerading as arrhythmogenic right ventricular cardiomyopathy awaiting heart transplant

SummaryWe report a case of 45-year-old man, who was diagnosed with arrhythmogenic right ventricular cardiomyopathy (ARVC) and presented with right ventricular (RV) enlargement with a global decrease in RV contractility accompanied by impairment of left ventricular function. He was placed on the heart transplant waiting list. Endomyocardial biopsy from RV septal wall did not show any evidence of sarcoidosis or inflammatory change. Four years after he was put on the heart transplant waiting list, a computed tomography chest scan for the purpose of anatomical evaluation for coronary sinus prior to biventricular pacing lead implantation incidentally showed bilateral hilar lymphadenopathy, which suggested the possibility of sarcoidosis. Biopsy of the inguinal lymph node pathologically was consistent with sarcoidosis. The 2[18F]fluoro-2-deoxy-d-glucose positron emission tomography scanning (FDG-PET) demonstrated intense uptake in the myocardium, and the patient was finally diagnosed as having cardiac sarcoidosis. After steroid treatment, the abnormal FDG-PET uptake disappeared. The patient therefore represented a case of cardiac sarcoidosis masquerading as ARVC. It should be recognized that RV involvement is one of the manifestations in cardiac sarcoidosis

Improved long-term performance of pulsatile extracorporeal left ventricular assist device

SummaryBackground and purposeThe majority of heart transplant (HTx) candidates require left ventricular assist device (LVAD) support for more than 2 years before transplantation in Japan. However, the only currently available device is the extracorporeal pulsatile LVAD. The long-term management of extracorporeal LVAD support has improved remarkably over the years. To determine which post-operative management factors are related to the long-term survival of patients on such LVAD, we retrospectively compared the incidence of complications and their management strategies between the initial and recent eras of LVAD use, classified by the year of LVAD surgery.MethodsSixty-nine consecutive patients supported by extracorporeal pulsatile LVAD as a bridge to HTx between 1994 and 2007 were reviewed retrospectively. The patients were assigned according to the time of LVAD surgery to either group A (n=30; between 1994 and 2000) or group B (n=39; between 2001 and 2007).ResultsPatients in group B survived significantly longer on LVAD support than those in group A (674.6 vs. 369.3 days; p<0.001). The 1- and 2-year survival rates were significantly higher in group B than that in group A (82% vs. 48%, p<0.0001; 68% vs. 23%, p<0.0001, respectively). The proportion of deaths due to cerebrovascular accidents was lower (17% vs. 50%, p<0.001) in group B compared with group A. The incidences of systemic infection were similar in both groups, but the proportions of patients alive and achieving transplant surgery after systemic infection were higher in group B than those in group A (55% vs. 14%, p<0.01; 14% vs. 36%, p<0.05, respectively).ConclusionsThe long-term survival of patients even on “first-generation” extracorporeal LVAD has improved significantly in the recent era. Careful management of cerebrovascular accidents and systemic infection will play important roles in the long-term LVAD management

Transgenic Monkey Model of the Polyglutamine Diseases Recapitulating Progressive Neurological Symptoms

Age-associated neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and the polyglutamine (polyQ) diseases, are becoming prevalent as a consequence of elongation of the human lifespan. Although various rodent models have been developed to study and overcome these diseases, they have limitations in their translational research utility owing to differences from humans in brain structure and function and in drug metabolism. Here, we generated a transgenic marmoset model of the polyQ diseases, showing progressive neurological symptoms including motor impairment. Seven transgenic marmosets were produced by lentiviral introduction of the human ataxin 3 gene with 120 CAG repeats encoding an expanded polyQ stretch. Although all offspring showed no neurological symptoms at birth, three marmosets with higher transgene expression developed neurological symptoms of varying degrees at 3–4 months after birth, followed by gradual decreases in body weight gain, spontaneous activity, and grip strength, indicating time-dependent disease progression. Pathological examinations revealed neurodegeneration and intranuclear polyQ protein inclusions accompanied by gliosis, which recapitulate the neuropathological features of polyQ disease patients. Consistent with neuronal loss in the cerebellum, brain MRI analyses in one living symptomatic marmoset detected enlargement of the fourth ventricle, which suggests cerebellar atrophy. Notably, successful germline transgene transmission was confirmed in the second-generation offspring derived from the symptomatic transgenic marmoset gamete. Because the accumulation of abnormal proteins is a shared pathomechanism among various neurodegenerative diseases, we suggest that this new marmoset model will contribute toward elucidating the pathomechanisms of and developing clinically applicable therapies for neurodegenerative diseases.ArticleeNeuro.4(2):e0250(2017)journal articl

The spotted gar genome illuminates vertebrate evolution and facilitates human-teleost comparisons

To connect human biology to fish biomedical models, we sequenced the genome of spotted gar (Lepisosteus oculatus), whose lineage diverged from teleosts before teleost genome duplication (TGD). The slowly evolving gar genome has conserved in content and size many entire chromosomes from bony vertebrate ancestors. Gar bridges teleosts to tetrapods by illuminating the evolution of immunity, mineralization and development (mediated, for example, by Hox, ParaHox and microRNA genes). Numerous conserved noncoding elements (CNEs; often cis regulatory) undetectable in direct human-teleost comparisons become apparent using gar: functional studies uncovered conserved roles for such cryptic CNEs, facilitating annotation of sequences identified in human genome-wide association studies. Transcriptomic analyses showed that the sums of expression domains and expression levels for duplicated teleost genes often approximate the patterns and levels of expression for gar genes, consistent with subfunctionalization. The gar genome provides a resource for understanding evolution after genome duplication, the origin of vertebrate genomes and the function of human regulatory sequences

Two genetic variants of CD38 in subjects with autism spectrum disorder and controls

金沢大学医薬保健研究域医学系The neurobiological basis of autism spectrum disorder (ASD) remains poorly understood. Given the role of CD38 in social recognition through oxytocin (OT) release, we hypothesized that CD38 may play a role in the etiology of ASD. Here, we first examined the immunohistochemical expression of CD38 in the hypothalamus of post-mortem brains of non-ASD subjects and found that CD38 was colocalized with OT in secretory neurons. In studies of the association between CD38 and autism, we analyzed 10 single nucleotide polymorphisms (SNPs) and mutations of CD38 by re-sequencing DNAs mainly from a case-control study in Japan, and Caucasian cases mainly recruited to the Autism Genetic Resource Exchange (AGRE). The SNPs of CD38, rs6449197 (p 70; designated as high-functioning autism (HFA)) in the U.S. 104 AGRE family trios, but not with Japanese 188 HFA subjects. A mutation that caused tryptophan to replace arginine at amino acid residue 140 (R140W; (rs1800561, 4693C>T)) was found in 0.6-4.6% of the Japanese population and was associated with ASD in the smaller case-control study. The SNP was clustered in pedigrees in which the fathers and brothers of T-allele-carrier probands had ASD or ASD traits. In this cohort OT plasma levels were lower in subjects with the T allele than in those without. One proband with the T allele who was taking nasal OT spray showed relief of symptoms. The two variant CD38 poloymorphysms tested may be of interest with regard of the pathophysiology of ASD. © 2010 Elsevier Ireland Ltd and the Japan Neuroscience Society