Publications by authors named "Kazuhiro Sakai"

Hematopoietic stem and progenitor cell (HSPC) transplantation is a curative treatment of hematological disorders that has been utilized for several decades. Although umbilical cord blood (UCB) is a promising source of HSPCs, the low dose of HSPCs in these preparations limits their use, prompting need for ex vivo HSPC expansion. To establish a more efficient method to expand UCB HSPCs, we developed the bioactive peptide named SL-13R and cultured UCB HSPCs (CD34+ cells) with SL-13R in animal component-free medium containing a cytokine cocktail.

View Article and Find Full Text PDF

Pulses of narrow line-width optical photons can be used to calibrate and test sub-2 eV full-width at halfmaximum (FWHM) energy resolution transition-edge sensor (TES) microcalorimeters at low energies (< 1 keV), where it is very challenging to obtain X-ray calibration lines comparable to (or narrower than) the detector resolution. This scheme depends on the ability to resolve the number of 3 eV photons in each pulse, which we have recently demonstrated up to photon numbers of about 300. At LTD-18 we showed preliminary results obtained with this technique on a 0.

View Article and Find Full Text PDF

Purpose: We aimed to cross-sectionally investigate how work and sleep conditions could be associated with excessive fatigue symptoms as an early sign of Karoshi (overwork-related cerebrovascular and cardiovascular diseases; CCVDs).

Methods: We distributed a questionnaire regarding work, sleep, and excessive fatigue symptoms to 5410 truck drivers, as the riskiest occupation for overwork-related CCVDs, and collected 1992 total samples (response rate: 36.8%).

View Article and Find Full Text PDF

Background: Measuring lung compliance is useful for evaluating progression of interstitial lung disease (ILD), because reduced lung compliance due to fibrosis progression is the main cause of decreased vital capacity. However, because insertion of a balloon into the esophagus is invasive, lung compliance is rarely measured. A recently developed method uses fingertip photoplethysmography to estimate intrathoracic pressure.

View Article and Find Full Text PDF

Objectives: To follow up arising occupational health (OH) issues, measures taken, and their performances in the Fukushima Daiichi Nuclear Power Plant since 2014, and thus share experiences and extend the contribution of OH to long-term decommissioning work and preparation for future disasters.

Methods: Necessary information from official reports and through the OH-related activities involved was collected and analyzed.

Results: The issues were categorized into establishment of the OH management system, three individual issues, and others.

View Article and Find Full Text PDF

Objectives: At the Fukushima Daiichi Nuclear Power Plant, run by the Tokyo Electric Power Company, new procedures were introduced as part of the fitness for duty program in July 2016. These were designed to ensure that treatment and further investigations identified as necessary during health examinations were carried out. This study aimed to assess the effectiveness of the initiative by testing whether workers who needed further health examinations obtained them promptly, and whether the number with unmet health needs decreased and the number of workers being treated increased.

View Article and Find Full Text PDF

Na-K-2Cl cotransporter 2 (NKCC2) in thick ascending limb (TAL) in the kidney plays a central role in tubuloglomerular feedback (TGF) system by sensing NaCl delivery to the distal tubules. Although accumulating data indicate that dysregulated TGF contributes to the progression of diabetic complications, the regulation of NKCC2 in diabetes mellitus (DM) remains unclear. We here show that NKCC2 is overactivated via a vasopressin receptor 2 (V2R)-dependent mechanism in db/db mice, a mouse model of obese DM.

View Article and Find Full Text PDF

Lynx is an x-ray telescope, one of four large satellite mission concepts currently being studied by NASA to be a flagship mission. One of Lynx's three instruments is an imaging spectrometer called the Lynx x-ray microcalorimeter (LXM), an x-ray microcalorimeter behind an x-ray optic with an angular resolution of 0.5 arc sec and ∼2 m of area at 1 keV.

View Article and Find Full Text PDF

Recent clinical studies indicate that the disturbed phosphate metabolism in chronic kidney disease (CKD) may facilitate kidney injury; nonetheless, the causal role of phosphate in CKD progression remains to be elucidated. Here, we show that intestinal phosphate binding by sucroferric oxyhydroxide (SF) ameliorates renal injury in the rat remnant kidney model. Sprague-Dawley rats received 5/6 nephrectomy (RK) and had a normal chow or the same diet containing SF (RK + SF).

View Article and Find Full Text PDF
Hitomi X-ray studies of Giant Radio Pulses from the Crab pulsar.

Publ Astron Soc Jpn Nihon Tenmon Gakkai

April 2018

To search for giant X-ray pulses correlated with the giant radio pulses (GRPs) from the Crab pulsar, we performed a simultaneous observation of the Crab pulsar with the X-ray satellite Hitomi in the 2 - 300 keV band and the Kashima NICT radio observatory in the 1.4 - 1.7 GHz band with a net exposure of about 2 ks on 25 March 2016, just before the loss of the Hitomi mission.

View Article and Find Full Text PDF

Background: Numerous workers have participated in recovery efforts following the accident that occurred at the Tokyo Electric Power Company (TEPCO) Fukushima Daiichi Nuclear Power Plant after the Great East Japan Earthquake. These workers, belonging to various companies, have been engaged in various tasks since the accident. Given the hazards and stress involved in these tasks and the relatively long time required to transport sick or injured workers to medical institutions, it became necessary to quickly implement a more stringent management program for fitness for duty than in ordinary work environments.

View Article and Find Full Text PDF

Background: Although hyperphosphatemia is deemed a risk factor of the progression of chronic kidney disease (CKD), it remains unclear whether the normal range of serum phosphorus likewise deteriorates CKD. A propensity score analysis was applied to examine the causal effect of the normal range of serum phosphorus on the incidence of end-stage renal disease (ESRD).

Methods: A retrospective CKD cohort of 803 participants in a single institution was analyzed.

View Article and Find Full Text PDF

Objective: To clarify the occupational health (OH) issues that arose, what actions were taken, and the OH performances during the disaster involving the Fukushima Daiichi Nuclear Power Plant and thus improve the OH management system with respect to long-term decommissioning work and preparation for future disasters.

Methods: We used information in advisory reports to the Tokyo Electric Power Company by an OH expert group, observation through support activities, and data officially released by the Tokyo Electric Power Company.

Results: Occupational health issues transitioned as work progressed and seasons changed.

View Article and Find Full Text PDF

The purpose of this study was to clarify the characteristic of workloads on human care worker with the introduction of IT system, and suggested the support measures for KAIZEN in Japan. The investigation method is workflow line and hearing with a focus on work observation. The objects were 8 human care workers of the acute hospital that introduced an electronic system.

View Article and Find Full Text PDF

In this paper, we introduce the new workflow line system consisted of the location and image recording, which led to the acquisition of workflow information and the analysis display. From the results of workflow line investigation, we considered the anticipated effects and the problems on KAIZEN. Workflow line information included the location information and action contents information.

View Article and Find Full Text PDF

Objective: The effect of a severely stressful situation (sleep restriction and psychological load) on the diurnal changes in novel tryptamine-related compounds (hydroxydiacetyltryptamine, sulphatoxymelatonin, and dihydromelatonin) was evaluated in human subjects for 16 days.

Methods: The subjects were allowed to sleep for 5 h on days three through 12 and for 8 h on the other days. On days three through 12, the subjects were asked to perform a psychological task.

View Article and Find Full Text PDF

Background: Previous studies have pointed out that the school lunch workers in Japan are suffering from work-related disorders including finger deformations. The purpose of this study was to investigate the prevalence of self-reported finger deformations and the association with job-related risk factors.

Methods: A cross-sectional questionnaire study of 5,719 subjects (response rate: 81%, 982 men and 4,737 women) was undertaken during September 2003 to February 2004.

View Article and Find Full Text PDF

Background: No reliable precursor of sudden cardiac death is known.

Methods And Results: Holter electrocardiograms of 34 patients experiencing a cardiac event (event group, 20 deaths) were compared with 191 controls (no event group). The event group included 25 patients with ventricular fibrillation or acute myocardial infarction (AMI), and 9 with cardiac arrest due to complete atrioventricular block.

View Article and Find Full Text PDF

During our studies to establish a method for identifying tryptamine-related substances in human urine, we detected three large peaks of unknown origin in an HPLC chromatogram. Fluorometric HPLC and HPLC-TOF-MS/MS analyses led to the identification of these substances as 6-sulphatoxymelatonin, 5-sulphatoxydiacetyltryptamine, and reduced melatonin. This is the first report of the latter two compounds in human urine.

View Article and Find Full Text PDF

Background: Approximately 5% of motor vehicle deaths are assumed to be occur because of a cardiac event thought to be triggered by multiple factors. One important factor is an imbalance of sympathetic and parasympathetic nervous activities, which can be measured by analyzing heart rate variability (HRV). Therefore, a system has been developed to make electrocardiographic (ECG) recordings outside the driver's awareness from the steering wheel (steering-ECG) with an algorithm to remove noise.

View Article and Find Full Text PDF

The UN-GHS, a globally harmonized system of classifying and labeling chemicals that was recommended by the United Nations in 2003, will be implemented globally in 2008. This system is expected to encourage people to behave in a way that reduces the risk of accidents or diseases caused by chemicals. However, the UN-GHS differs significantly from the present Japanese system of classifying and labeling chemicals.

View Article and Find Full Text PDF

Background: The prevalence of self-reported low back pain among professional cooks was estimated to examine the effects of daily life conditions, job-related factors, and psychological factors on this disorder.

Methods: Data was collected using a mailed self-administered questionnaire.

Results: Of 7100 cooks, 5835 (82%) replied to the questionnaire, including 1010 men and 4825 women.

View Article and Find Full Text PDF

Serial participatory action programs for reducing occupational safety and health risks were undertaken to know the types of support suited for small-scale industries. Working groups were formed with workplace people and occupational safety and health experts. It was agreed to develop an action-oriented strategy focusing on improving both work environment and productivity by making low-cost improvements through group work.

View Article and Find Full Text PDF