Image-based evaluation of contraction–relaxation kinetics of human-induced pluripotent stem cell-derived cardiomyocytes: Correlation and complementarity with extracellular electrophysiology

AbstractIn this study, we used high-speed video microscopy with motion vector analysis to investigate the contractile characteristics of hiPS-CM monolayer, in addition to further characterizing the motion with extracellular field potential (FP), traction force and the Ca2+ transient. Results of our traction force microscopy demonstrated that the force development of hiPS-CMs correlated well with the cellular deformation detected by the video microscopy with motion vector analysis. In the presence of verapamil and isoproterenol, contractile motion of hiPS-CMs showed alteration in accordance with the changes in fluorescence peak of the Ca2+ transient, i.e., upstroke, decay, amplitude and full-width at half-maximum. Simultaneously recorded hiPS-CM motion and FP showed that there was a linear correlation between changes in the motion and field potential duration in response to verapamil (30–150nM), isoproterenol (0.1–10μM) and E-4031 (10–50nM). In addition, tetrodotoxin (3–30μM)-induced delay of sodium current was corresponded with the delay of the contraction onset of hiPS-CMs. These results indicate that the electrophysiological and functional behaviors of hiPS-CMs are quantitatively reflected in the contractile motion detected by this image-based technique. In the presence of 100nM E-4031, the occurrence of early after-depolarization-like negative deflection in FP was also detected in the hiPS-CM motion as a characteristic two-step relaxation pattern. These findings offer insights into the interpretation of the motion kinetics of the hiPS-CMs, and are relevant for understanding electrical and mechanical relationship in hiPS-CMs

Crucial role of nitric oxide synthases system in endothelium-dependent hyperpolarization in mice

The endothelium plays an important role in maintaining vascular homeostasis by synthesizing and releasing several relaxing factors, such as prostacyclin, nitric oxide (NO), and endothelium-derived hyperpolarizing factor (EDHF). We have previously demonstrated in animals and humans that endothelium-derived hydrogen peroxide (H2O2) is an EDHF that is produced in part by endothelial NO synthase (eNOS). In this study, we show that genetic disruption of all three NOS isoforms (neuronal [nNOS], inducible [iNOS], and endothelial [eNOS]) abolishes EDHF responses in mice. The contribution of the NOS system to EDHF-mediated responses was examined in eNOS−/−, n/eNOS−/−, and n/i/eNOS−/− mice. EDHF-mediated relaxation and hyperpolarization in response to acetylcholine of mesenteric arteries were progressively reduced as the number of disrupted NOS genes increased, whereas vascular smooth muscle function was preserved. Loss of eNOS expression alone was compensated for by other NOS genes, and endothelial cell production of H2O2 and EDHF-mediated responses were completely absent in n/i/eNOS−/− mice, even after antihypertensive treatment with hydralazine. NOS uncoupling was not involved, as modulation of tetrahydrobiopterin (BH4) synthesis had no effect on EDHF-mediated relaxation, and the BH4/dihydrobiopterin (BH2) ratio was comparable in mesenteric arteries and the aorta. These results provide the first evidence that EDHF-mediated responses are dependent on the NOSs system in mouse mesenteric arteries

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Exploration of the Factor Structure of the Burden Experienced by Individuals Providing End-of-Life Care at Home

In Japan, the number of elderly people who require long-term care is increasing as a result of the country’s aging population. Consequently, the burden experienced by caregivers who provide end-of-life care at home has become a social problem. This study aimed to confirm the factor structure of such caregiver burden by analyzing the Japanese version of the Zarit Caregiver Burden Interview (J-ZBI). The J-ZBI was administered to 389 caregivers providing end-of-life care, and 247 answers were analyzed, with exploratory factor analysis performed on the results. Consequently, a four-factor structure emerged (sacrificing life, personal strain, severe anxiety, and captivity); these four factors, constituting 15 items, were cumulatively named “J-ZBI_15.” In regard to reliability, Cronbach’s α coefficient for each factor was high; in terms of validity, a confirmatory factor analysis was conducted to examine the four-factor structure, and the goodness of model fit was determined to be satisfactory. Further, the convergent validity was also high. The care burden experienced by those providing end-of-life care at home differs from the burden of caregivers of individuals with other diseases, such as Alzheimer’s. For assessing the burden felt by this population, the 15-item four-factor ZBI model is more appropriate than the single-factor 22-item ZBI, and we also determined that J-ZBI_8 is unsuitable for this task. Thus, measurement of family caregivers’ burden in regard to providing end-of-life care at home should be performed using the 15-item four-factor J-ZBI model

The Supply of Rice from Hita and Kusu district to Nagasaki in Edo Period

The purpose of this paper is to study the supply of rice to Nagasaki in Edo period, especially 18th-19th century, by focusing on the system called ‘Kaikae-osame’, which was done in Hita and Kusu district in Bungo Country known as the biggest Shogunal place in Kyushu area. ‘ Kaikae-osame' is the system of replacement some rice with other rice when people in both district supplied rice to Edo,Osaka and Nagasaki as tax paying.The first chapter examines the outline of ‘Kaikae-osame'. In the system, villages needed to furnish rice first. For example, in Terauchi-village people had to furnish rice in two way. One was as to carry to Nagasaki directly, and the other was as to replacement. Second the contractor of ‘ Kaikaemai' received rice from village, and then they bought other rice in north of Kyushu area, such as the Kurume clan, the Kumamoto clan, the Fukuoka clan.The second chapter shows the system of ‘Kaikae-osame' in detail. The most of the contractors of ‘ Kaikae-mai' were merchants in Hita distrid. The system was supported by them. As a result, the system of ‘Kaikae-osame' is shown at the schema. It is cl ear that through the system the contractor of ‘Kaikae-mai' effected the rice circulation in northern Kyushu area