Prevalence of musculoskeletal pain in an elderly Korean population: Results from the Korean Longitudinal Study on Health and Aging (KLoSHA)

The aim of this study is to estimate the prevalence of musculoskeletal (MSK) pain in the upper extremities (UE), low back, and lower extremities (LE) in an elderly population, and to identify related factors. In this cross-sectional cohort study, 1118 Korean elderly subjects were randomly selected from residents aged ≥65 years living in an urban city of Korea. The study data included presence of MSK pain, educational levels, activity levels over a 24 h, monthly income, body mass indices and presence of depression. Estimated age- and gender-standardized prevalences of UE, low back, and LE pain were 62.6%, 72.6%, and 45.7%, respectively. The prevalence of LE pain increased with age, whereas those of UE pain and back pain did not. By multivariate analysis, a female gender and a low income were found to be significantly associated with pain at all sites, and obesity was related with low back and LE pain. Furthermore, an uneducated state was found to be associated with LE pain, and major depressive disorder to be obviously related to UE and LE pain. MSK pain was identified to be a common problem in the elderly Korean population, and a female gender was consistently associated with MSK pain.     

Sinus floor elevation using implants coated with recombinant human bone morphogenetic protein-2: micro-computed tomographic and histomorphometric analyses

Clinical Oral Investigations - The objective of this study was to determine the validity of a graft-free sinus floor elevation (SFE) procedure with simultaneous placement of recombinant...     

Silk peptides inhibit adipocyte differentiation through modulation of the Notch pathway in C3H10T1/2 cells

Silk protein is a biocompatible material that has been used in many biotechnological applications and exhibits body fat-lowering effects. Recent studies have shown that silk peptides increase expression of osteogenic markers in osteoblast-like cells. Because osteogenic and adipogenic differentiation from common mesenchymal progenitor cells are inverse processes and often regulated reciprocally, we hypothesized that silk peptides might suppress adipocyte differentiation. We therefore endeavored to evaluate the effects of silk peptides on adipocyte differentiation in C3H10T1/2 cells. We find that silk peptides inhibit lipid accumulation and morphological differentiation in these cells. Molecular studies show that silk peptides block expression of adipocyte-specific genes such as peroxisome proliferator-activated receptor γ and its targets, including aP2, Cd36, CCAAT enhancer binding proteinα. Silk peptides appear to inhibit adipogenesis by suppression of the Notch pathway, repressing the Notch target genes Hes-1 and Hey-1. In addition, these peptides inhibit endogenous Notch activation, as shown by a reduction in generation of Notch intracellular domain. N-[N-(3.5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butylester, compound E, and WPE-III-31C, which are all known Notch signaling inhibitors, block adipocyte differentiation to an extent similar to silk peptides. Together, our data demonstrate that silk peptides can modulate adipocyte differentiation through inhibition of the Notch signaling and further suggest potential future strategies for treating obesity and its related metabolic diseases.     

Effects of chronic exposure to acidic environment on the response of tumor cells to radiation

Purpose: The influence of short-term exposure to an acidic environment on the radiosensitivity of tumor cells has been extensively explored, but the implication of chronic exposure to an acidic environment for the response of tumor cells to radiation has not been fully elucidated. This study aimed to investigate the effects of chronic pre- and post-irradiation exposure of tumor cells to an acidic environment on the radiation-induced clonogenic death.

Materials and methods: Rat gliosarcoma cells were used throughout the in vitro study. Cells were exposed to pH 6.6 medium for varying durations of up to 4 days before and after X-irradiation. Cell viability, apoptosis, clonogenic cell death and cell cycle distribution were observed.

Results: Incubation of tumor cells in pH 6.6 medium for 2 or 4 days extended cell cycle, decreased cell viability, and induced apoptotic and clonogenic cell death. The radiation-induced clonogenic death was increased by 2- or 4-day pre-irradiation exposure of tumor cells to pH 6.6 medium, whereas it was reduced by 4-day post-irradiation exposure to an acidic medium.

Conclusion: Prolonged exposure to an acidic environment enhanced the sensitivity of tumor cells to subsequent X-irradiation. However, the radiosensitization by pre-irradiation exposure was almost completely nullified by prolonged post-irradiation exposure to an acidic environment.     

Mechanism of the stationary canalicular excretion of tributylmethyl ammonium in rats with a CCl4-induced acute hepatic injury

The in vivo canalicular excretion clearance of tributylmethyl ammonium (TBuMA), a P-glycoprotein (P-gp) substrate, was previously reported to be unaffected by the induction of an experimental hepatic injury (EHI) by CCl(4) despite the increased expression of P-gp in the EHI liver. The objective of this study, therefore, was to elucidate the mechanism for the unchanged canalicular excretion clearance of TBuMA in EHI rats. TBuMA uptake was increased in cLPM vesicles from EHI rats compared with that from control rats. The total bile salt concentration in EHI liver was significantly reduced compared with that in a control liver. Because, in our previous studies, the uptake of TBuMA by cLPM vesicles was found to be significantly enhanced in the presence of bile salts, the reduction in bile salt levels in the EHI liver may be related to the unaltered TBuMA clearance. Despite the fact that the uptake of TBuMA by cLPM vesicles was increased by the addition of an EHI liver extract, the extent of the increase was comparatively less compared to the addition of a control liver extract. The in vivo excretion clearance of TBuMA was increased in a taurodeoxycholate dose-dependent manner in EHI rats. These observations suggest, therefore, that despite the induction of P-gp expression by the EHI, the in vivo canalicular excretion clearance of TBuMA remains unaltered as the result of an offset by reduced levels of bile salt(s).     

Feasibility study on the use of gold nanoparticles in fractionated kilovoltage X-ray treatment of melanoma

Purpose: Despite the high radioresistance of melanoma, unresectable lesions can be subjected to radiation treatment with the use of gold nanoparticles (AuNPs) as a dose-enhancing agent preferentially loaded on these lesions. The modality of single high-dose treatment has been investigated to confirm its therapeutic efficiency for AuNP-treated melanoma cells. This study explores the feasibility of utilizing AuNPs in fractionated radiation therapy of melanoma for further therapeutic gain.

Materials and methods: The responses of human skin melanoma cells to 150-kVp X-ray exposure at 2 and 4?Gy were assessed by quantify gamma-H2AX expression and clonogenic survival, with or without 320 μM of 50?nm AuNP treatment in a culture medium. The influence of AuNPs on cell cycle distribution was observed before irradiation and during 3 d period after irradiation.

Results: The AuNP treatment of melanoma cells influenced the cellular response to kilovoltage X-rays to similar extents in terms of the percentage of gamma-H2AX-positive cells and the fractional loss of clonogenicity. Without radiation exposure, AuNPs reduced the portion of melanoma cells at the G₂/M phase from 11 to 7%. After irradiation, the progression of the melanoma cells treated with AuNPs toward the G₂/M phase was more rapid than that of the AuNP-free cells, and the release of the former from the G₂/M phase was slower than that of the latter. At 24?h after irradiation with AuNPs, the cell cycle was rearranged in a pattern that increased the vulnerability of the cells to radiation damage.

Conclusions: In addition to the benefit of AuNP treatment to the control of melanoma in single high-dose treatment, further therapeutic gain is expected through fractionated X-ray treatment that involves daily exposure. The AuNP-treated melanoma cells of an increased portion in the radiosensitive G₂/M phase following a fractionated dose delivery would respond to the next treatment with an enhanced chance of clonogenic death.     

Gold nanoparticles as dose-enhancement agent for kilovoltage X-ray therapy of melanoma

Purpose: Melanoma is mainly treated by surgery and rarely with radiation because of the high radioresistance of this tumor. Nevertheless, radiotherapy is the preferred treatment modality for unresectable lesions and avoiding cosmetic disfigurement caused by surgical excision. This study investigated the therapeutic advantage of gold nanoparticles (AuNPs) for kilovoltage X-ray treatment of melanoma.

Materials and methods: Commercial AuNPs were evaluated for cytotoxicity and cellular internalization. The sensitivity of human skin melanoma cells to 150 and 450 kVp X-ray exposure was assessed in terms of clonogenicity with or without spherical AuNP treatment.

Results: AuNP treatment elicited dose enhancement effect on melanoma cells exposed to kilovoltage X-rays. Treatment with 320?μM 50?nm AuNPs before exposure to 150 kVp X-rays at 2?Gy resulted in clonogenic cell death equivalent to that caused by 4.3?Gy X-rays without AuNP treatment.

Conclusion: AuNPs of 50?nm in size can regulate melanoma cells in kilovoltage X-ray treatment by functioning as dose-enhancement agent and thus improving radioresponse of the cells. Melanomas of stages T1–T3 gain therapeutic benefits from 150 kVp X-ray treatment.