Densities of sandy beach organisms along coastlines often vary considerably even within small local scales. In order to understand the demographic basis of density variations in shore animals, we examined the population dynamics of the amphipod Haustorioides japonicus Kamihira, which is an ideal subject because it lacks a planktonic dispersal stage in its life history. Quantitative sampling at three adjacent sandy beaches along the Sea of Japan coast revealed that the spring density, i.e., the density of overwintered individuals, was similar among the three beaches. However, the amount of recruitment of newly hatched juveniles from late spring to summer greatly differed among the beaches, resulting in large spatial variations in the summer density. Cohort analyses revealed that at all beaches, young‐of‐the‐year (YOY) individuals reproduced and then died, and that individuals which recruited in late summer overwintered. Moreover, growth, fecundity, and survival schedules of overwintered and YOY individuals were very similar among beaches. These observations suggest that the difference in recruitment success, i.e., the survival of newly hatched juveniles, is the primary cause of the inter‐population variation in the summer density. It is likely that variations in salinity and sandy sediment affect the recruitment success of newly hatched individuals. This study indicates that biological productivity may differ substantially even among adjacent sandy beaches, with important implications for beach management.

Sandy beach habitats are mainly controlled by the physical environmental factors. This study investigated the effects of winter storms on populations of sandy beach infaunal peracarids. Two contrasting areas on the Japan Sea coast were selected: exposed sandy beaches in Niigata and protected sandy beaches in Sado. Regional differences in the mortality rate of two species of peracarids, Haustorioides japonicus and Excirolana chiltoni, were examined over two years, focusing on periods of high storm intensity (fall and winter) when sandy beach habitats are frequently disturbed. The results demonstrated that: (1) the mortality rate on the exposed beaches (Niigata) was significantly higher than that on the protected beaches (Sado); (2) the mortality rate in 2009-2010 was significantly higher than that in 2008-2009; and (3) the mortality rates were not significantly different between the two species. Sediment grain size, sorting coefficient, and beach slope were not different between the two study areas. Dominant waves during the stormy seasons were from the northwest, to which the beaches in Niigata were directly exposed. Moreover, mean wave height was higher in 2009-2010 than in 2008-2009. Therefore, the variations in wave disturbances were herein considered to be the major cause of the mortality variations in the two species. According to the predicted scenarios of climate changes, wave intensification will likely increase in the future, therefore increasing the mortality and the potential risk of local extinctions of these sandy beach infaunal animals.

Background: Sodium magnetic resonance imaging can non-invasively assess sodium distribution, specifically sodium concentration in the countercurrent multiplication system in the kidney, which forms a sodium concentration gradient from the cortex to the medulla, enabling efficient water reabsorption. This study aimed to investigate whether sodium magnetic resonance imaging can detect changes in sodium concentrations under normal conditions in mice and in disease models such as a mouse model with diabetes mellitus. Methods: We performed sodium and proton nuclear magnetic resonance imaging using a 9.4-T vertical standard-bore super-conducting magnet. Results: A condition of deep anesthesia, with widened breath intervals, or furosemide administration in 6-week-old C57BL/6JJcl mice showed a decrease in both tissue sodium concentrations in the medulla and sodium concentration gradients from the cortex to the medulla. Further, sodium magnetic resonance imaging revealed reductions in the sodium concentration of the medulla and in the gradient from the cortex to the medulla in BKS.Cg-Leprdb+/+ Leprdb/Jcl mice at very early type-2 diabetes mellitus stages compared to corresponding control BKS.Cg-m+/m+/Jcl mice. Conclusions: The kidneys of BKS.Cg-Leprdb+/+ Leprdb/Jcl mice aged 6 weeks showed impairments in the countercurrent multiplication system. We propose the utility of 23Na MRI for evaluating functional changes in diabetic kidney disease, not as markers that reflect structural damage. Thus, 23Na MRI may be a potential very early marker for structures beyond the glomerulus; this may prompt intervention with novel efficacious tubule-targeting therapies.

Background The post-dialysis plasma level of human atrial natriuretic peptide (hANP) reflects the fluid volume in patients on hemodialysis. The threshold hANP level is reportedly 100 pg/mL; however, the clinical usefulness of the threshold hANP level for volume control has not been sufficiently studied. Methods We conducted a single-center, retrospective, observational study that included 156 hemodialysis patients without atrial fibrillation. First, we examined the usefulness of the threshold hANP level (100 pg/mL) for predicting hypoxemia due to congestion in a short-term observational study from December 30, 2015 to January 5, 2016. Subsequently, we conducted a 5-year follow-up study wherein the outcomes were hospitalization due to acute heart failure (AHF), development of cardiovascular diseases (CVD), and all-cause death. Finally, we collected echocardiography data to investigate the relationship between cardiac function and hANP. Results Our short-term observational study showed that patients with an hANP level ≥ 100 pg/mL developed hypoxemia due to congestion (odds ratio, 3.52; 95% confidence interval, 1.06–11.71; P = 0.040). At the 5-year follow-up, patients with an hANP level ≥ 100 pg/mL had significantly higher rates of hospitalization due to AHF, CVD, and all-cause death based on the log-rank test (P = 0.003, P = 0.019, P < 0.001, respectively). Cardiac disfunctions were significantly associated with the high hANP level. Conclusions The hANP level is indicative of both fluid volume and cardiac dysfunction. A threshold hANP level of 100 pg/mL can serve as a predictive marker for AHF and a practical indicator for volume control.

Background and Aims Volume overload leads to the development of heart failure, which contributes to the high mortality in patients on hemodialysis. The post-dialysis plasma level of human atrial natriuretic peptide (hANP) reflects the fluid volume in patients on hemodialysis. The threshold hANP level is reportedly 100 pg/mL; however, the clinical usefulness of the threshold hANP level for volume control has not been sufficiently studied. Method We conducted a single-center, retrospective, observational study that included 156 hemodialysis patients without atrial fibrillation. First, we examined the usefulness of the threshold hANP level (100 pg/mL) for predicting hypoxemia due to congestion in a short-term observational study from December 30, 2015 to January 5, 2016. Subsequently, we conducted a 5-year follow-up study wherein the outcomes were hospitalization due to acute heart failure (AHF), development of cardiovascular diseases (CVD), and all-cause death. Finally, we collected echocardiography data to investigate the relationship between cardiac function and hANP. Results Our short-term observational study showed that patients with an hANP level ≥ 100 pg/mL developed hypoxemia due to congestion (odds ratio, 3.52; 95% confidence interval, 1.06–11.71; P = 0.040). At the 5-year follow-up, patients with an hANP level ≥ 100 pg/mL had significantly higher rates of hospitalization due to AHF, CVD, and all-cause death based on the log-rank test (P = 0.003, P = 0.019, P &lt; 0.001, respectively). Analysis of echocardiography data showed that the presence of reduced left ventricular ejection fraction and left ventricular diastolic disfunction were significantly associated with high plasma hANP levels. However, the threshold hANP level (100 pg/mL) remained independently associated with hospitalization due to AHF after adjusting for cardiac disfunctions in the multivariable model. Conclusion The hANP level is indicative of both fluid volume and cardiac dysfunction. In clinical practice, we suggest utilizing hANP as an easily accessible measure to identify high-risk patients for developing AHF initially. If the hANP level exceeds 100 mg/dL, we propose to perform echocardiography and consider reducing the DW. In clinical practice, the plasma hANP level could serve as a valuable indicator for assessing the risk of developing AHF and managing fluid volume.