Trace elements influenced by environmental changes in Lake Biwa: (I) Seasonal variations under suboxic hypolimnion conditions during 2007 and 2009

Dissolved oxygen (DO) in the Lake Biwa hypolimnion reached its lowest level of <1 mg kg^?1 in 2007. In this paper, we report the variations in the total dissolvable (TD), dissolved (D), and labile particulate (LP) fractions of Al, Si, P, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Mo, W, and U in Lake Biwa 2007 and 2009. Al and Fe species were predominantly in the form of LP-Al and LP-Fe and were strongly correlated with one another (r = 0.99), suggesting that the weathering of aluminous minerals and the supply of clay mineral particles are the main factors that influence the distributions of Al and Fe. Although D-Al increased in the summer epilimnion, D-Fe was relatively low, probably as a result of uptake by plants. Reductive release of Fe from the bottom was not seen. Mn was also dominated by LP-Mn, but this fraction showed a different distribution to those of LP-Al and LP-Fe. The D-Mn and LP-Mn concentrations varied by factors of 700–1000 and showed marked increases in the bottom water during stratification in 2007. We believe that Mn²⁺ was released from the sediments and oxidized by DO in the bottom water. Ni, Cu, Zn, and Cr, which exist as cationic species, had LP/TD ratios of 0.1–0.7 and relatively uniform distributions. Si, P, V, As, Mo, W, and U, which form oxoacid species, had LP/TD ratios of 0–0.8. Si, P, and As were characterized by nutrient-like profiles, V, W, and U showed summer maxima in the epilimnion, and Mo had a uniform distribution. TD-Mo increased in the bottom water along with TD-Mn, while TD-V and TD-W showed significant decreases. These results are likely attributable to differences in the adsorption of these elements onto manganese oxides and iron hydroxides.     

Quantitative and antioxidative behavior of Trolox in rats’ blood and brain by HPLC‐UV and SMFIA‐CL methods

Trolox, a water‐soluble vitamin E analogue has been used as a positive control in Trolox equivalent antioxidant capacity and oxygen radical antioxidant capacity assays due to its high antioxidative effect. In this study, the ex vivo antioxidative effects of Trolox and its concentration in blood and brain microdialysates from rat after administration were evaluated by newly established semi‐microflow injection analysis, chemiluminescence detection and HPLC‐UV. In the administration test, the antioxidative effect of Trolox in blood and brain microdialysates after a single administration of 200 mg/kg of Trolox to rats could be monitored. The antioxidative effects in blood (12.0 ± 2.1) and brain (8.4 ± 2.1, × 10³ antioxidative effect % × min) also increased. Additionally, the areas under the curve (AUC)s_0–360 (n = 3) for blood and brain calculated with quantitative data were 10.5 ± 1.2 and 9.7 ± 2.5 mg/mL × min, respectively. This result indicates that Trolox transferability through the blood–brain barrier is high. The increase in the antioxidative effects caused by Trolox in the blood and brain could be confirmed because good correlations between concentration and antioxidative effects (r ≥ 0.702) were obtained. The fact that Trolox can produce an antioxidative effect in rat brain was clarified. Copyright © 2015 John Wiley & Sons, Ltd.     

Production of endothelial progenitor cells obtained from human Wharton's jelly using different culture conditions

Endothelial progenitor cells (EPC) participate in revascularization and angiogenesis. EPC can be cultured in vitro from mononuclear cells of peripheral blood, umbilical cord blood or bone marrow; they also can be transdifferentiated from mesenchymal stem cells (MSC). We isolated EPCs from Wharton's jelly (WJ) using two methods. The first method was by obtaining MSC from WJ and characterizing them by flow cytometry and their adipogenic and osteogenic differentiation, then applying endothelial growth differentiating media. The second method was by direct culture of cells derived from WJ into endothelial differentiating media. EPCs were characterized by morphology, Dil-LDL uptake/UEA-1 immunostaining and testing the expression of endothelial markers by flow cytometry and RT-PCR. We found that MSC derived from WJ differentiated into endothelial-like cells using simple culture conditions with endothelium induction agents in the medium.     

Constitutively active parathyroid hormone receptor signaling in cells in osteoblastic lineage suppresses mechanical unloading-induced bone resorption

Multiple signaling pathways participate in the regulation of bone remodeling, and pathological negative balance in the regulation results in osteoporosis. However, interactions of signaling pathways that act comprehensively in concert to maintain bone mass are not fully understood. We investigated roles of parathyroid hormone receptor (PTH/PTHrP receptor) signaling in osteoblasts in unloading-induced bone loss using transgenic mice. Hind limb unloading by tail suspension reduced bone mass in wild-type mice. In contrast, signaling by constitutively active PTH/PTHrP receptor (caPPR), whose expression was regulated by the osteoblast-specific Col1a1 promoter (Col1a1-caPPR), suppressed unloading-induced reduction in bone mass in these transgenic mice. In Col1a1-caPPR transgenic (Tg) mice, hind limb unloading suppressed bone formation parameters in vivo and mineralized nodule formation in vitro similarly to those observed in wild-type mice. In addition, serum osteocalcin levels and mRNA expression levels of type I collagen, Runx2 and Osterix in bone were suppressed by unloading in both wild-type mice and Tg mice. However, in contrast to unloading-induced enhancement of bone resorption parameters in wild-type mice, Col1a1-caPPR signaling suppressed, rather than enhanced, osteoclast number and osteoclast surface as well as urinary deoxypyridinoline excretion upon unloading. Col1a1-caPPR signaling also suppressed mRNA expression levels of RANK and c-fms in bone upon unloading. Although the M-CSF and monocyte chemoattractant protein 1 (MCP-1) mRNA levels were enhanced in control Tg mice, these levels were suppressed in unloaded Tg mice. These results indicated that constitutive activation of PTH/PTHrP receptor signaling in osteoblastic cells suppresses unloading-induced bone loss specifically through the regulation of osteoclastic activity.     

Role of PKC and TGF-beta receptor in glucose-induced proliferation of smooth muscle cells

The role of protein kinase C (PKC) and transforming growth factor (TGF)-beta in the proliferation of vascular smooth muscle cells (SMCs) under a high glucose condition was investigated. [3H]-thymidine incorporation under 20 mM glucose was significantly accelerated compared with that under 5.5 mM glucose, and this increase was inhibited by an anti-TGF-beta antibody or a PKC-beta specific inhibitor, LY333531. The amount of active and total TGF-beta1 in the conditioned media did not differ between 5.5 and 20 mM glucose. However, the expression of TGF-beta receptor type II under 20 mM glucose was significantly increased, but that of the TGF-beta receptor type I was not. This increased expression of the TGF-beta receptor type II was prevented by LY333531. These observations suggest that the increased expression of the TGF-beta receptor type II via PKC-beta plays an important role in the accelerated proliferation of SMCs under a high glucose condition, leading to the development of diabetic macroangiopathy.     

Inhibitory effects of fluvastain and its metabolites on the formation of several reactive oxygen species

We investigated the inhibitory effects of fluvastain (FV) and its metabolites (M-2, M-3, M-4, M-5, and M-7) on the formation of several reactive oxygen species (ROS), such as singlet oxygen (1O2), superoxide anion (O2-), hydroxy radical (*OH), hypochlorite ion (OCL-), and linoleic acid peroxide (LOO*). Inhibitory effects of pravastatin (PV), simvastatin (SV), probucol (PR) and alpha-tocopherol (TOC) were also tested. The inhibitory effects of 5-hydroxy FV (M-2) and 6-hydroxy FV (M-3) on the formation of 1O2, O2-, *OH, and OCL- were strongest. Scavenging of 1O2 by M-4, M-5, (+)-FV, and (-)-FV was also noted. The inhibitory effects of (+)-FV on the formation of 1O2 were comparable to those of (-)-FV, PV, SV, PR and M-7 had little or no inhibitory effect on the formation of several ROS. In conclusion, FV and its metabolites, particulary M-2 and M-3, have the potential to protect against oxidative stress mediated by several ROS.