Search

In consultation with academia and the Pharmaceuticals and Medical Devices Agency (PMDA), we have developed guidance for drafting protocols for clinical trials concerning medical devices for the healing of hard-to-heal wounds without ischaemia. The guidance summarises the validity of single-arm trials for hard-to-heal wounds, the definition of hard-to-heal wounds without ischaemia, methods of patient enrolment and clinical endpoints. This review focuses on the logical thinking process that was used when establishing the guidance for improving the efficiency of clinical trials concerning medical devices for hard-to-heal wounds. We particularly focused on the feasibility of conducting single-arm trials and also tried to clarify the definition of hard-to-heal wounds. If the feasibility of randomised control trials is low, conducting single-arm trials should be considered for the benefit of patients. In addition, hard-to-heal wounds were defined as meeting the following two conditions: wounds with a wound area reduction <50% at four weeks despite appropriate standards of care; and wounds which cannot be closed by a relatively simple procedure (for example, suture, skin graft and small flaps). Medical devices for hard-to-heal wound healing are classified into two types: (1) devices for promoting re-epithelialisation; and (2) devices for improving the wound bed. For medical devices for promoting re-epithelialisation, we suggest setting complete wound closure, percent wound area reduction or distance moved by the wound edge as the primary endpoint in single-arm trials for hard-to-heal wounds. For medical devices for improving the wound bed, we suggest setting the period in which wounds can be closed by secondary intention or a simple procedure, such as the primary endpoint. Declaration of interest: The authors have no conflicts of interest directly relevant to the content of this article. The authors' views expressed in the present article do not necessarily reflect the official views of the Pharmaceuticals and Medical Devices Agency. [ABSTRACT FROM AUTHOR]

Substitution of Al atoms in a zeolite framework by catalytic metal atoms has attracted considerable attention because the catalytic behavior can be tuned by the substituted atoms. In the present study, Sn-substituted MFI-type silicates were synthesized using a hydrothermal reaction of an amorphous Si-O-Sn precursor prepared by mechanochemical grinding of SiO2 and Sn(OH)4. The mechanochemical treatment was found to be a key technique for obtaining the amorphous Si-O-Sn precursor, where tetrahedral Sn4+ species were incorporated into the amorphous matrix. The Sn content in the framework of the MFI-type silicates was successfully controlled by the initial HCl/Si molar ratio of the hydrothermal procedures. Optical reflectance measurements revealed that the Sn4+ ions were dispersedly incorporated into the silicate framework while preserving the initial tetrahedrally coordinated species. Infrared results imply that the resulting Sn-substituted MFI-type silicate has Brønsted acid character. Precise control of the Brønsted and Lewis acid properties by Sn doping is a promising approach to the development of novel types of zeolite-based catalytic materials.

Abstract Background Previously, we reported that a low-protein diet significantly reduced insulin secretion in response to feeding within 1 h in rats, suggesting that the insulinotropic effect of dietary protein plays an important role in maintaining normal insulin release. The current study aimed to elucidate whether deficiency of certain amino acids could diminish the insulinotropic activity and to investigate whether reduced insulin secretion in response to a low-protein diet is restored by supplementation with certain amino acids. Methods First, we fed male Wistar rats (5–6 rats per group) with diets deficient in every single amino acid or three branched-chain amino acids (BCAAs); within 1–2 h after the onset of feeding, we measured the plasma insulin levels by using an enzyme-linked immunosorbent assay (ELISA). As insulin secretion was reduced in BCAA-deficient groups, we fed low-protein diets supplemented with BCAAs to assess whether the reduced insulin secretion was restored. In addition, we treated the pancreatic beta cell line MIN6 with BCAAs to investigate the direct insulinotropic activity on beta cells. Lastly, we investigated the effect of the three BCAAs on sham-operated or vagotomized rats to assess involvement of the vagus nerve in restoration of the insulinotropic activity. Results Feeding a low-protein diet reduced essential amino acid concentrations in the plasma during an absorptive state, suggesting that reduced plasma amino acid levels can be an initial signal of protein deficiency. In normal rats, insulin secretion was reduced when leucine, valine, or three BCAAs were deficient. Insulin secretion was restored to normal levels by supplementation of the low-protein diet with three BCAAs, but not by supplementation with any single BCAA. In MIN6 cells, each BCAA alone stimulated insulin secretion but the three BCAAs did not show a synergistic stimulatory effect. The three BCAAs showed a synergistic stimulatory effect in sham-operated rats but failed to stimulate insulin secretion in vagotomized rats. Conclusions Leucine and valine play a role in maintaining normal insulin release by directly stimulating beta cells, and supplementation with the three BCAAs is sufficient to compensate for the reduced insulinotropic activity of the low-protein diet, through the vagus nerve.

Differences of cell proliferation, cell cycle, and G1/S transition regulatory proteins of gingival fibroblasts derived from nifedipine-reactive patient (NIFr) and nifedipine-non-reactive patient (NIFn) in the presence of basic fibroblast growth factor (bFGF) were investigated to elucidate the mechanism of gingival overgrowth associated with nifedipine, one of the Ca2+-channel blockers. The proliferation rate of NIFr cells in the presence of bFGF significantly increased than NIFn cells. The proportion of NIFr cells that had undergone progression to the S and G2/M phases from the G0/G1 phase significantly increased compared to that in NIFn cells. Increases of pRB (Ser807/811), pCDK2 (Thr160), CDK2, and cyclin E protein levels in NIFr cells were greater than those in NIFn cells. The elevations of pRB (Ser780), RB, and cyclin A protein levels in NIFr cells did not differ from those of NIFn cells. The growth of NIFr cells was greater than that of NIFn cells as a result of the active G1/S transition of NIFr cells, as assessed by the increments of cyclin E, pCDK2, and pRB (ser807/811) protein in NIFr cells. Keywords:: gingival overgrowth, nifedipine, gingival fibroblast, cell cycle