Effects of six particulate metals on osteoblast-like MG-63 and HOS cells in vitro

The effects of six particulate metals (Al, Ti, Zr, Nb, Ta and Cr) on cell viability and alkaline phosphatase (ALP) activity were studied in vitro using two types of osteoblast-like cells, MG-63 and HOS cells. The cell viability in the presence of Al, Ti and Zr was depressed at lower concentrations than in the presence of Nb, Ta and Cr. The average sizes of the Al, Ti, Zr, Nb, Ta and Cr particulates were 6.48 microm, 16.99 microm, 5.07 microm, 14.18 microm, 8.32 microm and 23.27 microm respectively. The interaction of HOS cells with the particulates was more sensitive than that of MG-63 cells. ALP activity increased at higher concentrations only with the Al particulates; other experimental conditions did not exert an influence on ALP activity. These findings suggest that the cell viability of osteoblast-like cells might be influenced by particulate size and metal type, but ALP activity was not influenced by these factors.     

Biliary phenotype of hepatocellular carcinoma after preoperative transcatheter arterial chemoembolization

Background and Aim: Transcatheter arterial chemoembolization (TACE) is now the mainstay of treatment for non‐curative hepatocellular carcinoma (HCC), and hoped to have chemotherapeutic and ischemic effects; however, the histopathological changes of HCC caused by TACE have not been sufficiently discussed so far. We aimed to assess the morphological and immunohistochemical features of HCC treated with TACE by immunostaining cytokeratin (CK) 7, CK14, CK19 and vimentin, and to correlate these data with observed clinicopathological characteristics. Methods: Eighty cases of surgically resected HCC with preoperative TACE and 146 cases of HCC resected without TACE as a control were analyzed. Results: The incidences of intrahepatic metastasis, poorly differentiated histology, multinucleated giant cells, mitotic figures and cytoplasmic inclusion bodies in the TACE group were significantly higher than those in the non‐TACE group. The TACE group showed reactivity for CK7 in 56.3% (45/80) of patients, CK14 in 12.5% (10/80), CK19 in 23.8% (19/80) and vimentin in 6.3% (5/80) of patients. CK19 expression in the TACE group was significantly higher than in the non‐TACE group (P = 0.0423). There was no correlation between immunoreactivity and the number of times TACE was carried out, but the expression of CK19 and vimentin in the massive necrotic group was higher than that in the mild necrotic group (P = 0.0197, P = 0.0229, respectively). Only TACE was an independent determinant of CK19 expression in all cases by multivariate analysis. Conclusions: These results suggest that preoperative TACE may have an impact on the biliary phenotype of HCC. Some post‐therapeutic HCC patients might develop HCC with a biliary phenotype indicating more aggressive malignancies.     

The impact of new-onset diabetes on arterial stiffness after renal transplantation

New-onset diabetes after renal transplantation (NODAT) is known to be a potent risk factor for cardiovascular events. We therefore investigated the incidence and risk factors for NODAT, and evaluated surrogate endpoints of atherosclerosis in Japanese patients with stable renal function after renal transplantation. Seventy-nine patients were enrolled in the study, and a 75 g oral glucose tolerance test (OGTT) was performed in subjects excluding patients with known NODAT. We evaluated the risk factors for NODAT and the degree of atherosclerosis, determined by brachial-ankle pulse wave velocity (baPWV), ankle-brachial blood pressure index (ABPI) and intima-media thickness (IMT) of the carotid artery. Eleven patients diagnosed as NODAT had significantly higher fasting plasma glucose before transplantation, blood pressure, and incidence of hepatitis C virus (HCV) infection than patients without NODAT. Multivariate regression analysis revealed that the independent determinant of NODAT was fasting plasma glucose pre-transplantation, HCV infection and systolic blood pressure. The baPWV in patients with NODAT was significantly higher compared to that in patients without NODAT. In addition, the independent determinant of baPWV evaluated by multivariate regression analysis was an increase in systolic blood pressure and age, and a decrease of adiponectin levels. In conclusion, we found that high fasting plasma glucose prior to transplantation, HCV infection and high blood pressure are risk factors for NODAT in Japanese patients after renal transplantation. Since NODAT patients have advanced arterial stiffness probably due to high blood pressure, strict control of blood pressure will be important for preventing the development of cardiovascular disease in NODAT.     

Bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) transfection to human periosteal cells enhances osteoblast differentiation and bone formation

Periosteum has been demonstrated to contain mesenchymal progenitor cells differentiating to osteoblasts, and both bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) may play important roles in cell-based approaches to bone regeneration. The purpose of this study was to evaluate the feasibility and efficacy of BMP-2 and/or VEGF on periosteal cell differentiation to osteoblasts in vitro and ectopic bone formation in vivo. Human periosteum-derived cells were transfected with BMP-2, VEGF, BMP-2 + VEGF, or vehicle as a control by non-viral gene transfer and then cultured and implanted to nude mice intramuscularly. Real-time polymerase chain reaction analysis of the culture revealed that transgenes for BMP-2 and BMP-2 + VEGF induced more mRNA expression of alkaline phosphatase, collagen type I, and osteocalcin than VEGF and vehicle treatments; additionally, alizarin red S staining, alkaline phosphatase staining, and alkaline phosphatase activity were significantly higher in the BMP-2 + VEGF transgene than in the other versions. After implantation, ectopic bone was observed at 4 weeks and greatly increased at 8 weeks in all groups. In particular, the combination of BMP-2 and VEGF formed significantly more bone at 4 weeks, and VEGF transfection resulted in more blood vessels relative to the conditions without VEGF. Thus, VEGF might enhance BMP2-induced bone formation through modulation of angiogenesis.     

Properties and expression of a multidrug efflux pump AcrAB-KocC from Klebsiella pneumoniae

We previously reported that we had cloned genes responsible for multidrug resistance from the chromosomal DNA of Klebsiella pneumoniae MGH78578 using a drug-hypersusceptible Escherichia coli strain as a host. One of the recombinant plasmids pETV6 conferred resistance to host cells against a wide range of antimicrobial agents, dyes and detergents. It was revealed that this plasmid carried the acrBKp gene and a part of the acrAKp gene coding for a multidrug efflux pump belonging to the RND family. We cloned the whole acrAKpBKp operon of K. pneumoniae and characterized the pump. The AcrAB pump utilized TolC as an outer membrane component in cells of E. coli. Elevated energy-dependent efflux of ethidium was observed with cells possessing AcrAKp BKp-TolC. We cloned a gene coding for an ortholog of TolC from chromosomal DNA of K. pneumoniae, and designated it kocC. It seems that the AcrAKpBKp-KocC complex functions as a potent multidrug efflux pump in K. pneumoniae. We observed a higher level of expression of acrAKp in K. pneumoniae MGH78578, a multidrug resistant strain, compared with ATCC10031, a drug susceptible strain.     

Antipsychotics possessing antidepressive efficacy increase G<Subscript>olf</Subscript> protein in rat striatum

Rationale Paliperidone ER is a novel antipsychotic drug in an extended-release (ER) formulation. As with all antipsychotics, careful dose setting is necessary to avoid side effects. Objectives In this study, we measured striatal and extrastriatal dopamine D₂ receptor occupancy during paliperidone ER treatment in patients with schizophrenia using positron emission tomography (PET) to compare regional occupancy and to estimate the optimal dose. Materials and methods Thirteen male patients with schizophrenia participated in this 6-week multiple-dose study. Six of them took 3 mg of paliperidone ER per day, four took 9 mg, and three took 15 mg. Two to 6 weeks after first drug intake, two PET scans, one with [¹¹C]raclopride and one with [¹¹C]FLB 457, were performed in each patient on the same day. The relationship between the dose or plasma concentration of paliperidone and dopamine D₂ receptor occupancy was calculated. Results The dopamine D₂ receptor occupancies in the striatum measured with [¹¹C]raclopride and the temporal cortex measured with [¹¹C]FLB 457 were 54.2–85.5% and 34.5–87.3%, respectively. ED₅₀ values of the striatum and temporal cortex were 2.38 and 2.84 mg/day, respectively. There was no significant difference in dopamine D₂ receptor occupancy between the striatum and the temporal cortex. Conclusions The data from this study suggest that paliperidone ER at 6–9 mg provides an estimated level of dopamine D₂ receptor occupancy between 70–80% and that the magnitude of dopamine D₂ receptor occupancy is similar between the striatum and temporal cortex.