Bone marrow derived human mesenchymal stem cells (hMSCs) have attracted great interest from both bench and clinical researchers because of their pluripotency and ease of expansion ex vivo. However, these cells do finally reach a senescent stage and lose their multipotent potential. Proliferation of these cells is limited up to the time of their senescence, which limits their supply, and they may accumulate chromosomal changes through ex vivo culturing. The safe, rapid expansion of hMSCs is critical for their clinical application. Chromosomal aberration is known as one of the hallmarks of human cancer, and therefore it is important to understand the chromosomal stability and variability of ex vivo expanded hMSCs before they are used widely in clinical applications. In this study, we examined the effects of culturing under ambient (20%) or physiologic (5%) O₂ concentrations on the rate of cell proliferation and on the spontaneous transformation of hMSCs in primary culture and after expansion, because it has been reported that culturing under hypoxic conditions accelerates the propagation of hMSCs. Bone marrow samples were collected from 40 patients involved in clinical research. We found that hypoxic conditions promote cell proliferation more favourably than normoxic conditions. Chromosomal aberrations, including structural instability or aneuploidy, were detected in significantly earlier passages under hypoxic conditions than under normoxic culture conditions, suggesting that amplification of hMSCs in a low‐oxygen environment facilitated chromosomal instability. Furthermore, smoothed hazard‐function modelling of chromosomal aberrations showed increased hazard after the fourth passage under both sets of culture conditions, and showed a tendency to increase the detection rate of primary karyotypic abnormalities among donors aged 60 years and over. In conclusion, we propose that the continuous monitoring of hMSCs will be required before they are used in therapeutic applications in the clinic, especially when cells are cultured under hypoxic conditions.

Increased risks of acute pancreatitis in patients with type 2 diabetes mellitus have been reported recently in several countries. We aimed to estimate the risks of acute pancreatitis in Japanese patients with diabetes mellitus. We examined a large-scale hospital administrative database consisting of one million patients in 16 secondary medical care hospitals, from 2003 to 2010. The incidence rates of acute pancreatitis were estimated with cohort design; the odds ratios associated with diabetes mellitus and other comorbid risk factors were estimated with separate case-control analyses. In cohort analysis, the incidence of acute pancreatitis was higher in 14,707 diabetic patients than in 186,032 non-diabetic patients (4.75 vs. 1.65 per 1,000 patient-years) and increased in male patients and as age advanced. The adjusted odds ratio of acute pancreatitis in patients with diabetes mellitus was 1.86 (P<0.001) compared with non-diabetic patients in case-control analysis from 1,372 cases and 5,469 matched controls, which is consistent with the ones reported in previous studies. Alcoholism and gallstones were associated with a large increase in the risk of acute pancreatitis (adjusted odds ratio 13.40 and 14.29, respectively, P<0.001), although dyslipidemia was associated with significant risk reduction (adjusted odds ratio 0.62, P<0.001). This observational study ascertained the elevated incidence rates and risk of acute pancreatitis in Japanese patients with diabetes. The risk estimates in Japanese patients with diabetes were in agreement with the ones reported in previous studies, and the elevated risk of acute pancreatitis in patients with diabetes would be generalized in different locations/populations.

Background: The Japanese Ministry of Health, Labour and Welfare introduced Specific Health Checkups (SHC) to identify individuals at risk of metabolic syndrome (MS). This study aimed to describe the SHC database developed by the Japan Medical Data Center Co., Ltd. (JMDC) as a means of exploring lifestyle behaviors and lifestyle diseases among working generations.Methods: We conducted a retrospective, cross-sectional study of employees and their families using the JMDC-SHC database to describe the prevalence of lifestyle behaviors (smoking, exercise, dietary habits, drinking habits, and sleeping) and lifestyle diseases (MS, hypertension, dyslipidemia, and diabetes mellitus). Results were compared with data from the 2015 National Health and Nutrition Survey (NHNS) in Japan as a benchmark.Results: All 646,869 enrollees in the JMDC-SHC database were included, of whom 66.5% were men. Age ranged from 40–74 years. Compared with the results of the NHNS, the JMDC-SHC subjects were younger and had fewer MS components and a lower prevalence of diabetes and hypertension. Subjects in their 40s were most likely to have unhealthy lifestyle behaviors in all age groups (eg, smoking: 41.0% in men and 10.2% in women). The SHC group had more favorable behaviors overall, but underweight was more prevalent in the SHC females.Conclusions: The JMDC-SHC population showed different lifestyle and lifestyle disease profiles to the NHNS population, probably due to its different age, gender, and employment distributions. Development of healthcare policies and plans for working generations would benefit from the selection of an age- and employment-appropriate database.

Clinicians, researchers, regulators, and other decision-makers increasingly rely on evidence from real-world data (RWD), including data routinely accumulating in health and administrative databases. RWD studies often rely on algorithms to operationalize variable definitions. An algorithm is a combination of codes or concepts used to identify persons with a specific health condition or characteristic. Establishing the validity of algorithms is a prerequisite for generating valid study findings that can ultimately inform evidence-based health care. In this paper, we aim to systematize terminology, methods, and practical considerations relevant to the conduct of validation studies of RWD-based algorithms. We discuss measures of algorithm accuracy, gold/reference standards, study size, prioritization of accuracy measures, algorithm portability, and implications for interpretation. Information bias is common in epidemiologic studies, underscoring the importance of transparency in decisions regarding choice and prioritizing measures of algorithm validity. The validity of an algorithm should be judged in the context of a data source, and one size does not fit all. Prioritizing validity measures within a given data source depends on the role of a given variable in the analysis (eligibility criterion, exposure, outcome, or covariate). Validation work should be part of routine maintenance of RWD sources. This article is part of a Special Collection on Pharmacoepidemiology.

Therapeutic options for Parkinson's disease mainly consist of L-dopa and dopamine agonists. However, in Japan, the product labeling of the ergot dopamine agonists, cabergoline and pergolide, was revised in April 2007 due to the risk of developing cardiac valvulopathy. Here, we describe the prescribing trends of anti-Parkinson drugs from 2005 through 2010 in Japan, and examined whether these trends changed after the drug safety measures in 2007. We used medical claim data from January 2005 to December 2010 for Parkinson's disease patients older than 30 years who were prescribed anti-Parkinson drugs. We calculated the proportion of patients prescribed each drug for each year, and compared the proportions of first-line drugs prescribed before and after April 2007. We also examined the prescription variations of cabergoline/pergolide users one year before or after April 2007. L-dopa was the most frequently prescribed drug for Parkinson's disease (2005, 58%; 2010, 51%). The proportion of patients prescribed ergot dopamine agonists markedly decreased and non-ergot dopamine agonists increased after 2007. Among first-line drugs, the proportion of non-ergot agents increased after April 2007. Among 54 cabergoline/pergolide users, 24 (44%) discontinued these drugs, nine of whom switched to non-ergot agents. L-dopa was the mainstay of Parkinson's disease treatment between 2005 and 2010 in Japan. There was a decrease in ergot agents and an increase in non-ergot agents prescribed after the regulatory actions in 2007.