On the Dynamical Approach of Quantitative Radiation Biology

A quantitative approach in radiation biology based on the clonogenic method and cell survival curves in various conditions are introduced. The cell survival curves seem to have universality with regard to its functional form; in other words, functional form of survival curve seems to be unchanged under various conditions including different species. Various factors affecting the radiosensitivity have been introduced to find macroscopic nature of living organisms. Mathematical models that describe cell survival curves have been presented for discussing the derivation of the mathematical form based on biological mechanism. Finally, the possibility that the structural change of chromosome affects the repair process is discussed

Plasma adiponectin as a predictive factor of survival after a bypass operation for peripheral arterial disease

ObjectiveWe investigated an association between adiponectin and long-term survival in patients requiring an arterial bypass operation for peripheral arterial disease.MethodsAn enzyme-linked immunosorbent assay kit was used to measure plasma adiponectin levels in 49 patients (38 men, 11 women) before they underwent an arterial bypass operation. Median patient age was 70 years (range, 49-90 years). The study excluded patients with hemodialysis requirement, heart failure, malignant neoplasm, or collagen disease. The symptoms at the first visit were severe intermittent claudication in 27 patients (55%) and critical limb ischemia with rest pain or ulcer, or both, in 22 (45%).ResultsPlasma adiponectin levels were a mean 7.8 ± 5.3 μg/mL (range, 1.0-25.2 μg/mL). Multiple regression analyses revealed that plasma adiponectin was positively correlated with age (r = 0.49, P = .0003) and negatively correlated with body mass index (r = −0.51, P = .0002) and systolic blood pressure (r = −0.41, P = .0059). The Cox proportional hazards model revealed that plasma adiponectin (hazard ratio, 1.30; P = .03) and critical limb ischemia (hazard ratio, 16.67; P = .047) were significant independent predictors of patient survival after a bypass operation.ConclusionPlasma adiponectin could be indicative of mortality after a bypass operation for patients with advanced peripheral arterial disease

Omentin Prevents Myocardial Ischemic Injury Through AMP-Activated Protein Kinase- and Akt-Dependent Mechanisms

ObjectivesThis study examined the impact of omentin on myocardial injury in a mouse model of ischemia/reperfusion (I/R) and explored its underlying mechanisms.BackgroundObesity is a major risk factor for ischemic heart disease. Omentin is a circulating adipokine that is down-regulated by obesity.MethodsIn patients who underwent successful reperfusion treatment after acute myocardial infarction, cardiac function and perfusion defect were assessed by using scintigraphic images. Mice were subjected to myocardial ischemia followed by reperfusion.ResultsThis study found that high levels of plasma omentin were associated with improvement of heart damage and function after reperfusion therapy in patients with acute myocardial infarction. Systemic administration of human omentin to mice led to a reduction in myocardial infarct size and apoptosis after I/R, which was accompanied by enhanced phosphorylation of AMP-activated protein kinase (AMPK) and Akt in the ischemic heart. Fat-specific overexpression of human omentin also resulted in reduction of infarct size after I/R. Blockade of AMPK or Akt activity reversed omentin-induced inhibition of myocardial ischemic damage and apoptosis in mice. In cultured cardiomyocytes, omentin suppressed hypoxia/reoxygenation-induced apoptosis, which was blocked by inactivation of AMPK or Akt.ConclusionsOur data indicate that omentin functions as an adipokine that ameliorates acute ischemic injury in the heart by suppressing myocyte apoptosis through both AMPK- and Akt-dependent mechanisms

JASMINE: Near-infrared astrometry and time-series photometry science

The Japan Astrometry Satellite Mission for INfrared Exploration (JASMINE) is a planned M-class science space mission by the Institute of Space and Astronautical Science, the Japan Aerospace Exploration Agency. JASMINE has two main science goals. One is Galactic archaeology with a Galactic Center survey, which aims to reveal the Milky Way’s central core structure and formation history from Gaia-level (∼25 ${\mu}$as) astrometry in the near-infrared (NIR) Hw band (1.0–1.6 ${\mu}$m). The other is an exoplanet survey, which aims to discover transiting Earth-like exoplanets in the habitable zone from NIR time-series photometry of M dwarfs when the Galactic Center is not accessible. We introduce the mission, review many science objectives, and present the instrument concept. JASMINE will be the first dedicated NIR astrometry space mission and provide precise astrometric information on the stars in the Galactic Center, taking advantage of the significantly lower extinction in the NIR. The precise astrometry is obtained by taking many short-exposure images. Hence, the JASMINE Galactic Center survey data will be valuable for studies of exoplanet transits, asteroseismology, variable stars, and microlensing studies, including discovery of (intermediate-mass) black holes. We highlight a swath of such potential science, and also describe synergies with other missions