Effect of the combined use of enamel matrix derivative and atelocollagen sponge scaffold on osteoblastic differentiation of mouse induced pluripotent stem cells in vitro

BACKGROUND AND OBJECTIVE

Induced pluripotent stem cells (iPSCs) are a candidate cell source in periodontal regenerative therapy. Enamel matrix derivative (EMD) has been shown to regenerate periodontal tissues, and atelocollagen sponge (ACS) is considered a suitable scaffold or carrier for growth factors. This study aimed to investigate the effect of combined use of EMD and an ACS scaffold on cell behaviors and differentiation of mouse iPSCs (miPSCs) in vitro.

MATERIAL AND METHODS

Following embryonic body formation from miPSCs, dissociated cells (miPS-EB-derived cells) were seeded onto ACS with or without EMD, and cultured in osteoblast differentiation medium. Scanning electron microscopy and histological analyses were used to assess cell morphology and infiltration within the ACS. Cell viability (metabolism) was determined using an MTS assay, and expression of mRNA of osteoblastic differentiation markers was assessed by quantitative RT -PCR. Alkaline phosphatase (ALP) staining intensity and activity were evaluated. Mineralization was assessed by von Kossa staining, and calcium content was quantitated using the methylxylenol blue method.

RESULTS

By 24 hours after seeding, miPS-EB-derived cells in both the EMD and control groups had attached to and infiltrated the ACS scaffold. Scanning electron microscopy images revealed that by day 14, many cytoplasmic protrusions and extracellular deposits, suggestive of calcified matrix, were present in the EMD group. There was a time-dependent increase in cell viability up to day 3, but no difference between groups was observed at any time point. The levels expressed of ALP and osterix genes were significantly higher in the EMD group than in the control group. Expression of runt-related transcription factor 2 was increased in the EMD group compared with the control group on day 7. EMD upregulated the expression of bone sialoprotein and osteopontin on day 14, whereas expression of osteocalcin was lower at all time points. The staining intensity and activity of ALP were higher in the EMD group than in the control group. Mineralization levels and calcium contents were significantly higher in the EMD group throughout the observation period.

CONCLUSION

These data suggest that combining ACS with EMD increases levels of osteoblastic differentiation and mineralization in miPS-EB-derived cells, compared with ACS used alone.

A 5-year longitudinal study of association of maximum bite force with development of frailty in community-dwelling older adults

To determine whether maximum bite force (MBF), an objective measure of oral function, is associated with development of frailty in community-dwelling older adults. This prospective cohort study included community-dwelling Japanese adults aged 75 years at baseline (n = 322). Baseline MBF was measured using an electronic recording device (Occlusal Force-Meter GM10). Follow-up examinations, including physical fitness and anthropometric evaluation and structured questionnaires, were administered annually over a 5-year period to determine the incidence of frailty, which was defined by the presence of 3 or more of the following 5 components derived from the Cardiovascular Health Study: low level of mobility, low physical activity level, weakness, shrinking and poor endurance and energy. Adjusted hazard ratios (HRs) of incidence of frailty according to sex-stratified tertiles of baseline MBF were calculated using Cox proportional hazards regression models. During the follow-up, 49 participants (15.2%) developed frailty. Participants in the lower tertile of MBF exhibited a significantly greater risk of frailty than those in the upper tertile. After adjustment for sex, depression, diabetes and Eichner index, the adjusted HRs for frailty in the upper through lower tertiles of MBF were 1.00 (reference), 1.27 (95% confidence interval [CI]: 0.50-3.20) and 2.78 (95% CI: 1.15-6.72), respectively (P for trend = .01). Poor oral function, as indicated by low MBF, increases the risk of development of frailty among elderly men and women.

A Retrospective Study on the Safety and Efficacy of Leflunomide in Dogs

Background

Little clinical information is available concerning the use of leflunomide in dogs with immune‐mediated diseases.

Objectives

To report the safety and efficacy of leflunomide for the treatment of naturally occurring immune‐mediated diseases in dogs.

Animals

Ninety‐two dogs treated with leflunomide for management of suspected immune‐mediated diseases.

Methods

Retrospective medical record review from Jan 1995 to Dec 2014. Data that were extracted from the medical records included signalment, body weight, underlying indication for leflunomide, dosage of leflunomide, treatment duration, concurrent medications, treatment response, and adverse events.

Results

Adverse events that could be related to leflunomide administration included diarrhea (3 of 92, 3.3%), lethargy (2 of 92, 2.2%), unexplained hemorrhage (3 of 92, 3.3%), thrombocytopenia (2 of 31, 6.5%), and increased liver enzyme activities (1 of 16, 6.3%). Significant dose differences between dogs with adverse events (n = 11; median, 2.9 mg/kg/d; range, 1.8–3.6 mg/kg/d) and dogs without adverse events (n = 81; median, 1.6 mg/kg/d; range, 0.8–4.3 mg/kg/d) were found (P < 0.001). Treatment response could be evaluated in 17 dogs. Of these 17 dogs, 12 dogs (70.5%) had an apparent positive response to the use of leflunomide. There was no significant difference (P = 0.22) in dosages between dogs that responded to leflunomide (n = 12; median, 1.9 mg/kg/d; range, 1.0–3.5 mg/kg/d) and those that did not respond (n = 5; median, 1.7 mg/kg/d; range, 1.0–2.0 mg/kg/d).

Conclusions and Clinical Importance

Results suggest that the starting dosage of leflunomide should be 2 mg/kg/d rather than the currently suggested dosage of 3–4 mg/kg/d.

Clinical Results of Accelerated Hypofractionated Radiotherapy for Central-Type Small Lung Tumours

Purpose: We evaluated the efficacy and toxicity of accelerated hypofractionated radiotherapy (AHYPOF-RT) for central-type small lung tumours. Methods: Between November 2006 and January 2015, 40 patients with central-type small lung tumours underwent AHYPOF-RT delivered using 10 MV X-rays and a coplanar 3-field technique. The number of fractions ranged from 24 to 28, with a fraction size of 2.5–3 Gy. A total dose of 69–75 Gy to the isocentre of the planning target volume was administered to each patient. Cumulative survival and local control rates were calculated using the Kaplan–Meier method. Results: The 27 men and 13 women enrolled in the study had a median age of 79 years (range: 60−87 years). The tumour stage was T1a in 9 patients, T1b in 17 patients, and T2a in 14 patients, with a median size of 26.5 cm (range: 11–49 cm). The median follow-up period was 23 months. A complete response was achieved in 3 patients (7.5%), and a partial response, in 17 patients (42.5%). The overall 2-year and 3-year local control rates were 87.3% and 81.8% respectively; the 2-year and 3-year overall survival rates were 78.9% and 66.7% respectively. Grade 3 pneumonitis occurred in 3 patients; no other severe adverse events (≥grade 3) were observed in any patient. Conclusions: Accelerated hypofractionated radiotherapy using a fraction size of 2.5–3 Gy was highly safe and can be a more effective treatment option than conventional radiotherapy for patients with central-type small lung tumours.

Association between hospital volume and in-hospital mortality following radiofrequency ablation for hepatocellular carcinoma

Background

Radiofrequency ablation (RFA) is a minimally invasive treatment for hepatocellular carcinoma (HCC). There is increasing evidence of an association between increasing hospital volume and lower postoperative mortality for many surgical procedures, but this is difficult to establish with minimally invasive treatments, where postoperative mortality is low. The aim of this study was to investigate the relationship between hospital volume and in-hospital mortality following RFA using a Japanese nationwide database.

Methods

Data from the Diagnostic Procedure Combination database were analysed from 1 July 2010 to 31 March 2012. Multivariable logistic regression was used to analyse the relationship between hospital volume and in-hospital mortality following RFA, with adjustment for patient background.

Results

Some 36 675 patients with HCC were identified in the database. The overall in-hospital mortality rate from RFA was 0·31 per cent. In-hospital mortality was significantly higher in low-volume than high-volume hospitals (odds ratio 2·57, 95 per cent c.i. 1·61 to 4·09; P < 0·001). Higher in-hospital mortality was significantly associated with older age and a higher Charlson Co-morbidity Index score.

Conclusion

RFA for HCC was associated with acceptably low mortality in Japan, but in-hospital mortality following RFA was affected by hospital procedural volume.

Quantitative Modeling and Simulation in PMDA: A Japanese Regulatory Perspective

In Japan in October 2016, the Pharmaceuticals and Medical Devices Agency (PMDA) began to receive electronic data in new drug applications (NDAs). These electronic data are useful to conduct regulatory assessment of sponsors’ submissions and contribute to the PMDA's research. In this article, we summarize the number of submissions of quantitative modeling and simulation (M&S) documents in NDAs in Japan, and we describe our current thinking and activities about quantitative M&S in PMDA.