Nationwide survey of the coronavirus disease 2019 prevention and treatment systems for kidney disease patients: a study of Japanese Society of Nephrology-certified educational facilities.

BACKGROUND: There are no reports of a large-scale survey on the infection prevention measures against coronavirus disease 2019 (COVID-19) in nephrology facilities. This study investigated the facility-level nephrology practices adopted during the COVID-19 pandemic and their associated challenges. Additionally, the treatment patterns and outcomes of chronic kidney disease (CKD) patients with COVID-19 were reviewed. METHODS: We conducted a nationwide questionnaire survey of 704 educational facilities that were certified by the Japanese Society of Nephrology (JSN) from October 20, 2020 to November 16, 2020. The questionnaire reviewed the facility characteristics, infection prevention measures taken during routine nephrology practice, impact of COVID-19 on nephrology practice, experiences in managing CKD patients with COVID-19, and nosocomial transmission in the nephrology unit. RESULTS: Of the 347 facilities that responded, 95.1% checked outpatients' body temperatures and COVID-19 symptoms at their visits. To reduce face-to-face contact, 80% and 70% of the facilities lengthened the intervals between outpatient visits and introduced online/telephonic consultations, respectively. As a result, more than half of the hospitals experienced a decrease in the numbers of outpatients and inpatients (64% and 50%, respectively). During the study period, 347 facilities managed 479 CKD patients with COVID-19. Oxygen administration and mechanical ventilation were performed for 47.8% and 16.5% of the patients, respectively, with a 9.2% total mortality rate. CONCLUSION: This survey demonstrated that JSN-certified educational nephrology facilities adopted multiple measures to manage the COVID-19 pandemic; however, they faced several challenges. Sharing these experiences could standardize these approaches and prepare us better for the future.

Association of Circulatory Iron Deficiency With an Enlarged Heart in Patients With End-Stage Kidney Disease.

OBJECTIVES: High prevalence of iron deficiency (ID) and cardiomyopathy have been observed in patients with end-stage kidney disease (ESKD). Our objective was to clarify associations between ID and cardiac remodeling in patients with ESKD. DESIGN AND METHODS: A cross-sectional study was conducted using 1974 Japanese patients with ESKD at the initiation of maintenance dialysis. Levels of hemoglobin (Hb), iron status, and cardiac enlargement as assessed by the cardiothoracic ratio (CTR) were determined immediately before the first hemodialysis session. Circulatory ID was defined as transferrin saturation (TSAT) < 20%, and stored ID was defined as ferritin level <100 ng/dL. RESULTS: The mean age was 67 years. Median CTR was 54.0%. The prevalence of circulatory and stored ID was found to be 38% and 34%, respectively. CTR was higher in patients with circulatory ID than in those without. Even in ESKD patients without overhydration, significant negative association was observed between TSAT and CTR. Higher odds ratios in parallel with higher CTR categories compared with the reference category of CTR <45% were found in patients with TSAT <20% on multinomial analysis, but ferritin did not show any significant associations. The odds ratio for CTR >54% showed an upward trend in patients with TSAT <20% (odds ratio: 1.3) and <10% (odds ratio: 1.6) compared with the reference, even after adjusting for confounding variables such as Hb and ferritin. However, that phenomenon was eliminated by adding usage of an iron agent. CONCLUSIONS: Circulatory ID is closely associated with an enlarged heart independent of ferritin and Hb. Iron supplementation in the predialysis phase of chronic kidney disease may prevent cardiac remodeling independent of Hb level in patients chronic kidney disease.

Effect of Oral Alfacalcidol on Clinical Outcomes in Patients Without Secondary Hyperparathyroidism Receiving Maintenance Hemodialysis: The J-DAVID Randomized Clinical Trial.

Importance: Patients with chronic kidney disease have impaired vitamin D activation and elevated cardiovascular risk. Observational studies in patients treated with hemodialysis showed that the use of active vitamin D sterols was associated with lower risk of all-cause mortality, regardless of parathyroid hormone levels. Objective: To determine whether vitamin D receptor activators reduce cardiovascular events and mortality in patients without secondary hyperparathyroidism undergoing hemodialysis. Design, Setting, and Participants: Randomized, open-label, blinded end point multicenter study of 1289 patients in 207 dialysis centers in Japan. The study included 976 patients receiving maintenance hemodialysis with serum intact parathyroid hormone levels less than or equal to 180 pg/mL. The first and last participants were enrolled on August 18, 2008, and January 26, 2011, respectively. The final date of follow-up was April 4, 2015. Interventions: Treatment with 0.5 µg of oral alfacalcidol per day (intervention group; n = 495) vs treatment without vitamin D receptor activators (control group; n = 481). Main Outcomes and Measures: The primary outcome was a composite measure of fatal and nonfatal cardiovascular events, including myocardial infarctions, hospitalizations for congestive heart failure, stroke, aortic dissection/rupture, amputation of lower limb due to ischemia, and cardiac sudden death; coronary revascularization; and leg artery revascularization during 48 months of follow-up. The secondary outcome was all-cause death. Results: Among 976 patients who were randomized from 108 dialysis centers, 964 patients were included in the intention-to-treat analysis (median age, 65 years; 386 women [40.0%]), and 944 (97.9%) completed the trial. During follow-up (median, 4.0 years), the primary composite outcome of cardiovascular events occurred in 103 of 488 patients (21.1%) in the intervention group and 85 of 476 patients (17.9%) in the control group (absolute difference, 3.25% [95% CI, -1.75% to 8.24%]; hazard ratio, 1.25 [95% CI, 0.94-1.67]; P = .13). There was no significant difference in the secondary outcome of all-cause mortality between the groups (18.2% vs 16.8%, respectively; hazard ratio, 1.12 [95% CI, 0.83-1.52]; P = .46). Of the 488 participants in the intervention group, 199 (40.8%) experienced serious adverse events that were classified as cardiovascular, 64 (13.1%) experienced adverse events classified as infection, and 22 (4.5%) experienced malignancy-related serious adverse events. Of 476 participants in the control group, 191 (40.1%) experienced cardiovascular-related serious adverse events, 63 (13.2%) experienced infection-related serious adverse events, and 21 (4.4%) experienced malignancy-related adverse events. Conclusions and Relevance: Among patients without secondary hyperparathyroidism undergoing maintenance hemodialysis, oral alfacalcidol compared with usual care did not reduce the risk of a composite measure of select cardiovascular events. These findings do not support the use of vitamin D receptor activators for patients such as these. Trial Registration: UMIN-CTR Identifier: UMIN000001194.

The use of vitamin D analogs is independently associated with the favorable renal prognosis in chronic kidney disease stages 4-5: the CKD-ROUTE study.

BACKGROUND: Vitamin D analogs have generally been recommended for treatment of mineral bone disease in chronic kidney disease (CKD). However, the association between this treatment and CKD progression has not yet been established. METHODS: We designed a post hoc propensity score-matched cohort analysis derived from 3-year follow-up data of a prospective cohort. Adult participants with pre-dialysis CKD stages 4-5 who had newly been prescribed active vitamin D analogs during the observation period were eligible as matched cases. Then, matched controls were extracted from participants who had never been prescribed active vitamin D analogs. The primary outcome was a composite of end-stage renal disease or a 50 % reduction in estimated glomerular filtration rate (eGFR). A Cox proportional hazards model evaluated the association between the use of vitamin D analogs and the primary outcome. RESULTS: We enrolled 240 patients (males, 65 %). The number of matched cases and controls was 30 and 210, respectively. The primary outcome was observed in 94 patients, whereas 25 patients died. The mean ± standard deviation age and eGFR were 69 ± 12 years and 17 ± 5.7 ml/min/1.73 m2, respectively. In a Cox proportional hazard model, the use of vitamin D analogs was independently associated with a lower risk of the primary outcome (crude hazard ratio 0.41; 95 % confidence interval 0.19, 0.89; adjusted hazard ratio 0.38; 95 % confidence interval 0.17, 0.88). CONCLUSION: The use of vitamin D analogs is independently associated with the preservation of renal function in patients with pre-dialysis CKD stages 4-5.

Possible prevention of uremic nausea by vitamin D receptor activators in non-dialysis patients with stage 5 chronic kidney disease.

BACKGROUND: Nausea is a major uremic symptom and a frequent indication for starting dialysis. However, preventive medication for uremic nausea has not yet been identified. Vitamin D receptor activators (VDRAs) may prevent uremic nausea via their pleiotropic actions. The objective of this study was to explore whether VDRA administration during the predialysis period is associated with a reduced prevalence of uremic nausea just prior to beginning dialysis. METHODS: A multicenter, retrospective, cross-sectional study was performed to identify a medication to prevent uremic nausea. Patients with stage 5 CKD who were followed-up over 3 months were included. The primary outcomes examined were the prevalence of uremic nausea, congestive heart failure (CHF), and intractable edema at dialysis commencement. The predictor variable was VDRA use during the predialysis period. RESULTS: One thousand five hundred and thirty six patients who had just begun dialysis in nine Japanese facilities between January 2006 and October 2013 were included. Two hundred and thirty (15.0%) patients had commenced dialysis because of uremic nausea, and three hundred and ninety two (25.5%) patients had been using VDRAs before initiating dialysis. Logistic regression analysis showed that, among the medications examined in this study, only VDRA use was independently associated with a lower frequency of uremic nausea (OR 0.512, 95% CI 0.347-0.738, P = 0.0003). On the other hand, CHF and intractable edema were not associated with VDRA administration. CONCLUSION: Use of VDRAs during the predialysis period was the only factor associated with a lower prevalence of uremic nausea, suggesting that VDRAs may prevent uremic nausea in patients with advanced CKD.

[New Developments in CKD-MBD. Strategies for the management of predilalysis CKD-MBD].

Abnormalities in bone and mineral metabolism begin to develop in the early stage of CKD. Serum phosphorus, calcium, PTH, and alkaline phosphatase are recommended to be measured from CKD stage 3, and it is suggested that these markers are maintained within the reference ranges of each facility. The management of phosphorus is essential and is composed of phosphorus restriction and phosphate binders. Small amount of VDRA suppresses PTH for secondary hyperparathyroidism and is expected to reduce mortality and proteinuria. The effects of the intervention to reduce the phosphorus load before hyperphosphatemia is manifested need to be investigated.

6-(4-Pyridyl)pyrimidin-4(3H)-ones as CNS penetrant glycogen synthase kinase-3ß inhibitors.

The discovery of a series of 6-(4-pyridyl)pyrimidin-4(3H)-ones derived from a hit compound with low molecular weight and sufficient chemical space is reported. Transformation of substituents led to subnanomolar potent inhibitors with in vivo tau phoshorylation lowering activity.

Baseline characteristics and prevalence of cardiovascular disease in newly visiting or referred chronic kidney disease patients to nephrology centers in Japan: a prospective cohort study.

BACKGROUND: About 39,000 patients were newly prescribed renal replacement therapy in Japan in 2011, resulting in a total of more than 300,000 patients being treated with dialysis. This high prevalence of treated end stage kidney disease (ESKD) patients is an emergent problem that requires immediate attention. We launched a prospective cohort study to evaluate population specific characteristics of the progression of chronic kidney disease (CKD). In this report, we describe the baseline characteristics and risk factors for cardiovascular disease (CVD) prevalence among this cohort. METHODS: New patients from 16 nephrology centers who were older than 20 years of age and who visited or were referred for the treatment of CKD stage 2-5, but were not on dialysis therapy, were recruited in this study. At enrollment, medical history, lifestyle behaviors, functional status and current medications were recorded, and blood and urine samples were collected. Estimated glomerular filtration rate (eGFR) was calculated by a modified three-variable equation. RESULTS: We enrolled 1138 patients, 69.6% of whom were male, with a mean age of 68 years. Compared with Western cohorts, patients in this study had a lower body mass index (BMI) and higher proteinuria. The prevalence of CVD was 26.8%, which was lower than that in Western cohorts but higher than that in the general Japanese population. Multivariate analysis demonstrated the following association with CVD prevalence: hypertension (adjusted odds ratio (aOR) 3.57; 95% confidence interval (CI) 1.82-7.02); diabetes (aOR 2.45; 95% CI 1.86-3.23); hemoglobin level less than 11 g/dl (aOR 1.61; 95% CI 1.21-2.15); receiving anti-hypertensive agents (aOR 3.54; 95% CI 2.27-5.53); and statin therapy (aOR 2.73; 95% CI 2.04-3.66). The combination of decreased eGFR and increased proteinuria was also associated with a higher prevalence of CVD. CONCLUSIONS: The participants in this cohort had a lower BMI, higher proteinuria and lower prevalence of CVD compared with Western cohorts. Lower eGFR and high proteinuria were associated with CVD prevalence. Prospective follow up of these study patients will contribute to establishment of individual population-based treatment of CKD.

Effectiveness of SARS-CoV-2 vaccines on hemodialysis patients in Japan: A nationwide cohort study.

INTRODUCTION: This study compared the outcomes of dialysis patients who received SARS-CoV-2 vaccine with those who did not use data from the Japanese COVID-19 registry. METHODS: A total of 1260 dialysis patients with confirmed positive SARS-CoV-2 infection was included in this study. Patients were divided into two groups: patients who experienced breakthrough infection and those who were unvaccinated. The need of oxygen supplementation and mortality risks were compared using multivariate logistic regression analysis. RESULTS: The mortality rate was 24.2% in unvaccinated patients and 8.6% in breakthrough patients. The odds ratio of need of oxygen supplementation in the breakthrough patients relative to unvaccinated patients was 0.197. The hazard ratio of mortality in the breakthrough patients relative to unvaccinated patients was 0.464. CONCLUSION: Our prospective observational study showed that SRAS-CoV-2 vaccination in hemodialysis patients is vital for reducing need of oxygen supplementation and mortality risk.

Efficacy of molnupiravir and sotrovimab in Japanese dialysis patients with COVID-19 in clinical practice during the Omicron (BA.1 and BA.2) pandemic.

INTRODUCTION: In the present study, the efficacy of sotrovimab and molnupiravir in dialysis patients with COVID-19 was investigated using a registry of COVID-19 in Japanese dialysis patients. METHODS: Dialysis patients with confirmed SARS-CoV-2 during the COVID-19 (Omicron BA.1 and BA.2) pandemic were analyzed. Patients were classified into four treatment groups: molnupiravir monotherapy (molnupiravir group), sotrovimab monotherapy (sotrovimab group), molnupiravir and sotrovimab combination therapy (combination group), and no antiviral therapy (control group). The mortality rates in the four groups were compared. RESULTS: A total of 1480 patients were included. The mortality of the molnupiravir, sotrovimab, and combination groups were significantly improved compared to the control group (p < 0.001). Multivariate analysis indicated that antiviral therapy improves the survival of dialysis patients with COVID-19 (hazard ratio was 0.184 for molnupiravir, 0.389 for sotrovimab, and 0.254 for combination groups, respectively). CONCLUSION: Sotrovimab showed efficacy in Omicron BA.1 but attenuated in BA.2. Molnupiravir also showed efficacy in BA.2, suggesting administration of molnupiravir would be important.

Influence of renin-angiotensin system on serum parathyroid hormone levels in uremic patients.

INTRODUCTION: The aim of this study was to investigate the factors influencing serum parathyroid (PTH) levels, including medications for treating chronic kidney disease-mineral and bone metabolism disorder (CKD-MBD) in patients with end-stage renal disease. METHODS: We enrolled 1,076 patients in nine Japanese facilities who had begun hemodialysis (HD) due to ESRD. We investigated the relationships between intact PTH (iPTH) levels and clinical parameters and medications just prior to beginning HD. RESULTS: Significant decreases in serum iPTH levels were seen in males, in the presence of diabetes mellitus (DM), and with administration of renin-angiotensin system inhibitors (RASIs). Significant correlations were found between serum calcium and iPTH levels. In the patients administered RASIs, there was a significant decrease in serum iPTH levels with DM, male gender, and administration of active vitamin D sterols (VDs) compared with those not administered RASIs, although serum-corrected calcium levels were not different. Multiple regression analysis found gender, age, presence of DM, and serum calcium and phosphate levels to be significant contributing factors. In addition, administration of angiotensin II receptor blockers (ARBs) may also be a contributing factor to iPTH levels at the beginning HD (p = 0.050). CONCLUSIONS: In this study, serum iPTH levels were related to administration of ARBs besides gender, age, the presence of DM and serum calcium levels. Our study suggests that the RA system involve serum iPTH levels in uremic patients.

Nephrologist care for 12 months or more increases hemodialysis initiation with permanent vascular access.

BACKGROUND: The objective of this study was to evaluate the effect of early referral (ER) to nephrologists on the type of vascular access (VA) available for use at the time of initiation of maintenance hemodialysis (HD). In patients who have been followed by nephrologists for less than 3 months, management before the initiation of HD is often insufficient and urgent initiation of HD is often necessary; therefore, patients in this study were limited to those who had been followed for at least 3 months by nephrologists. METHODS: Nine hundred and forty patients at 9 institutions affiliated to our study group were enrolled in this retrospective observational study. We defined patients followed up by nephrologists for at least 12 months as the early referral (ER) group and those followed for between 3 and 12 months as the late referral (LR) group. The type of VA available for use at the initiation of maintenance HD was compared between the groups. RESULTS: Early referral was found to be significantly associated with the availability of a permanent VA, which included an arteriovenous fistula or arteriovenous graft, at the time of initiation of HD (odds ratio [OR] 1.705; P = 0.001). Multivariate analysis also revealed ER to be significantly associated with the availability of a permanent VA (OR 1.509; P = 0.023). CONCLUSION: Early referral was shown to be advantageous for increasing the likelihood of availability of a permanent VA, even after patients who had been followed up for less than 3 months by nephrologists were excluded.

False-negative diagnosis of high anion gap in patients with end-stage kidney disease.

The traditional anion gap (AG) equation is widely used, but its misdiagnosis in end-stage kidney disease (ESKD) patients has not been investigated fully. Diagnostic accuracy to detect high AG was cross-sectionally evaluated using 3 AG equations in 1733 ESKD patients with an eGFR less than 15 mL/min/1.73 m2. The prevalence of high AG was 67.9%, 92.1% and 97.4% by the traditional, albumin-adjusted AG (aAG) and full AG equations, respectively. The sensitivity, specificity, accuracy and Kappa coefficient obtained with the traditional AG vs aAG equation were 0.70 vs 0.94, 0.98 vs 0.93, 0.7 vs 0.94, and 0.103 vs 0.44, respectively. Next, we created a subcohort comprising only patients with high full AG and investigated how the traditional AG equation leads to misdiagnoses. Multivariable-adjusted regression analysis in 1688 patients revealed that independent factors associated with a false-negative AG diagnosis were ARB use, eGFR, blood leukocyte count, serum chloride, bicarbonate, ionized calcium, potassium, albumin and phosphate. 93.2% of our subcohort prescribed any of RAAS inhibitors, Loop diuretics or Alkali which could increase either serum chloride or bicarbonate. Frequent use of these possible AG-reducing medications may conceal high AG state in patients with ESKD unless they have incidental inflammation which may increase AG value.

Infection prevention measures for patients undergoing hemodialysis during the COVID-19 pandemic in Japan: a nationwide questionnaire survey.

BACKGROUND: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic affecting a variety of medical treatments, including hemodialysis. This study aims to investigate the implementation of infection control measures, to examine the shortage of personal protective equipment (PPE) and disinfectants, and to quantify the number of nosocomial COVID-19 transmissions in hemodialysis facilities in Japan during the pandemic. METHODS: We conducted a nationwide questionnaire survey between 20 October and 16 November 2020 (i.e., between the "second wave" and "third wave" in Japan) in the 4198 dialysis facilities of the Japanese Association of Dialysis Physicians and the Japanese Society for Dialysis Therapy. A total of 2227 facilities (53.0%) responded. The questionnaire consisted of (i) characteristics of facilities, (ii) infection prevention measures in routine dialysis practices, (iii) shortage of PPE, (iv) feasibility of various isolation measures, and (v) nosocomial transmission. RESULTS: Half of the responding facilities were hospitals with multiple departments, and the other half were clinics specialized in dialysis. Several infection prevention measures such as health checks of staff and patients, donning of masks before and after hemodialysis, and disinfection of frequently contacted areas were implemented during the COVID-19 pandemic. There was a significant improvement in the implementation rate of these measures during the pandemic, compared to before it, which reached over 90%. More than half of the facilities reported a shortage of disposable masks (67.2%) and hand sanitizer alcohol (56.7%). Isolation of COVID-19 patients in private rooms was possible only in 52.7% of the facilities. The majority of facilities (73.3%) could not accept COVID-19 dialysis patients due to lack of space and manpower. Nosocomial transmission of COVID-19 occurred in 4.0% of the facilities. Of those infected, 51.9% were staff. CONCLUSIONS: This survey revealed that most hemodialysis facilities in Japan had improved implementation of infection control measures and had shortage of PPEs and disinfectants, though some facilities did not implement infection prevention measures adequately, mainly due to the limited space of the facility. It may be recommended that each facility immediately establishes isolation measures to prepare for the pandemic of COVID-19. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s41100-021-00350-y.

Survival and predictive factors in dialysis patients with COVID-19 in Japan: a nationwide cohort study.

BACKGROUND: The Japanese Association of Dialysis Physicians, the Japanese Society for Dialysis Therapy, and the Japanese Society of Nephrology jointly established COVID-19 Task Force Committee and began surveying the number of newly infected patients. METHODS: This registry of the COVID-19 Task Force Committee was used to collect data of dialysis patients; a total of 1010 dialysis patients with COVID-19 were included in the analysis. Overall survival of patients was investigated with stratification by age group, complication status, and treatment. In addition, predictive factors for mortality were also investigated. The overall survival was estimated by Kaplan-Meier methods and compared by using log-rank test. Multivariate analysis was performed to identify the risk factor of mortality. For all statistical analyses, p < 0.05 was considered to be statistically significant. RESULTS: The mortality risk was increased with age (p < 0.001). The mortality risk was significantly higher in patients with peripheral arterial disease (HR: 1.49, 95% CI 1.05-2.10) and significantly lower in patients who were treated with remdesivir (HR: 0.60, 95% CI 0.37-0.98). Multivariate analysis showed increased risk of mortality with increment in BMI, and increment in CRP, and decreased risk with increment in albumin. CONCLUSION: Dialysis patients have a high severity of illness and a high risk of mortality in cases of COVID-19. Treatment with remdesivir might be effective in shortening the duration of hospitalization and reducing the risk of mortality.

Assessment and significance of abdominal aortic calcification in chronic kidney disease.

BACKGROUND: Abdominal aortic calcification is a common complication and a predictor of cardiovascular mortality in dialysis patients. However, abdominal aortic calcification in pre-dialysis chronic kidney disease (CKD) is poorly understood. METHODS: A cohort study of 101 adult Japanese patients (mean age 66.6 +/- 11.3 years old) with pre-dialysis CKD (18, 29 and 54 in stages 3, 4 and 5, respectively) was performed. At entry, a non-contrast computed tomography scan was used to determine the abdominal aortic calcification index (ACI). Clinical characteristics and laboratory variables were also assessed. The patients were followed for a mean period of 48 +/- 12 months. RESULTS: Among the subjects, 82% had abdominal aortic calcification (50, 83 and 91% for CKD stages 3, 4 and 5, respectively), and the median ACI was 16.7% (8.5, 20.0 and 21.4%, respectively). Multivariate logistic regression analyses identified older age, presence of diabetes and decreased estimated glomerular filtration rate (e-GFR) as independent predictors of the presence (ACI > 0%) and extent (ACI >or= 20%) of aortic calcification. Multivariate Cox proportional hazards analysis identified ACI >or= 20% and diabetes as independent predictors for de novo cardiovascular events in CKD stages 4 and 5. CONCLUSION: Decreased GFR may be associated with the presence and extent of abdominal aortic calcification, and a high level of calcification may be associated with de novo cardiovascular events in pre-dialysis CKD, suggesting that elucidation of the mechanism through which CKD contributes to vascular calcification may lead to an improved prognosis in patients with pre-dialysis CKD.

3-Cyano-6-(5-methyl-3-pyrazoloamino)pyridines: selective Aurora A kinase inhibitors.

A new class of Aurora A kinase inhibitor was created by transforming 4-(5-methyl-3-pyrazoloamino)pyrimidine moiety of VX-680 to 3-cyano-6-(5-methyl-3pyrazoloamino)pyridine. Compound 6 exhibited a potent Aurora A kinase inhibitory activity, excellent selectivity to Aurora B kinase and other 60 kinases, good cell permeability and good PK profile. Therefore compound 6 was effective in antitumor mice model at a dose of 30 mg/kg po qd without decrease of body weight.

Simulating Liquids on Dynamically Warping Grids.

We introduce dynamically warping grids for adaptive liquid simulation. Our primary contributions are a strategy for dynamically deforming regular grids over the course of a simulation and a method for efficiently utilizing these deforming grids for liquid simulation. Prior work has shown that unstructured grids are very effective for adaptive fluid simulations. However, unstructured grids often lead to complicated implementations and a poor cache hit rate due to inconsistent memory access. Regular grids, on the other hand, provide a fast, fixed memory access pattern and straightforward implementation. Our method combines the advantages of both: we leverage the simplicity of regular grids while still achieving practical and controllable spatial adaptivity. We demonstrate that our method enables adaptive simulations that are fast, flexible, and robust to null-space issues. At the same time, our method is simple to implement and takes advantage of existing highly-tuned algorithms.

COVID-19 of dialysis patients in Japan: Current status and guidance on preventive measures.

In Japan, the first case of COVID-19 in dialysis patients was reported on March 1, 2020. A total of 31 cases were reported by April 10, and it increased to 95 by May 15. Thereafter, with the rapid increase in the number of COVID-19 cases in the general population since late March, there was a not surprising increase in the number of COVID-19 cases in dialysis patients. The mortality rate is 16.2% (16/99 cases) in dialysis patients, which is higher than 5.3% (874/16 532 cases) in the general population. This higher mortality rate in dialysis patients with COVID-19 might be related to their age; the majority of COVID-19 cases are aged between 70 and 90 years old in dialysis patients, compared with between 20 and 60 years old in the general population. As COVID-19 presents with severe symptoms and is associated with a high mortality rate in dialysis patients, dialysis patients who have contracted severe acute respiratory syndrome coronavirus 2 infection confirmed by polymerase chain reaction testing are required to be hospitalized under Japanese government policy. In cases of COVID-19 hospitalizations, it is essential to prevent nosocomial infection. Therefore, patients must be sufficiently instructed in infection prevention and robust measures to prevent contraction and spread of the infection must be taken at dialysis facilities.