Visceral fat metabolic activity evaluated by F-FDG PET/CT is associated with osteoporosis in healthy postmenopausal Korean women.

Background: Traditionally, obesity has been regarded as protective against osteoporosis. However, recent accumulating evidences suggest that visceral obesity can increase the risk of osteoporosis and obesity-driven dysfunctional metabolic activity in visceral adipose tissue (VAT) is considered as a key underlying mechanism. Visceral obesity is known to increase during menopausal transition.

Targeting the Hepatocyte Growth Factor and c-Met Signaling Axis in Bone Metastases.

Bone metastasis is the terminal stage disease of prostate, breast, renal, and lung cancers, and currently no therapeutic approach effectively cures or prevents its progression to bone metastasis. One of the hurdles to the development of new drugs for bone metastasis is the complexity and heterogeneity of the cellular components in the metastatic bone microenvironment. For example, bone cells, including osteoblasts, osteoclasts, and osteocytes, and the bone marrow cells of diverse hematopoietic lineages interact with each other via numerous cytokines and receptors.

Effect of laser-dimpled titanium surfaces on attachment of epithelial-like cells and fibroblasts.

Purpose: The objective of this study was to conduct an in vitro comparative evaluation of polished and laserdimpled titanium (Ti) surfaces to determine whether either surface has an advantage in promoting the attachment of epithelial-like cells and fibroblast to Ti.

Materials And Methods: Forty-eight coin-shaped samples of commercially pure, grade 4 Ti plates were used in this study. These discs were cleaned to a surface roughness (Ra: roughness centerline average) of 180 nm by polishing and were divided into three groups: SM (n=16) had no dimples and served as the control, SM15 (n=16) had 5-µm dimples at 10-µm intervals, and SM30 (n=16) had 5-µm dimples at 25-µm intervals in a 2 × 4 mm(2) area at the center of the disc.

Tissue distribution and excretion kinetics of orally administered silica nanoparticles in rats.

Purpose: The effects of particle size on the tissue distribution and excretion kinetics of silica nanoparticles and their biological fates were investigated following a single oral administration to male and female rats.

Methods: Silica nanoparticles of two different sizes (20 nm and 100 nm) were orally administered to male and female rats, respectively. Tissue distribution kinetics, excretion profiles, and fates in tissues were analyzed using elemental analysis and transmission electron microscopy.

Optical imaging of absorption and distribution of RITC-SiO2 nanoparticles after oral administration.

Purpose: In this study, we investigated the absorption and distribution of rhodamine B isothiocyanate (RITC)-incorporated silica oxide nanoparticles(SiNPs) (RITC-SiNPs) after oral exposure, by conducting optical imaging, with a focus on tracking the movement of RITC-SiNPs of different particle size and surface charge.

Methods: RITC-SiNPs (20 or 100 nm; positively or negatively charged) were used to avoid the dissociation of a fluorescent dye from nanoparticles via spontaneous or enzyme-catalyzed reactions in vivo. The changes in the nanoparticle sizes and shapes were investigated in an HCl solution for 6 hours.

In vitro cytotoxicity of SiO2 or ZnO nanoparticles with different sizes and surface charges on U373MG human glioblastoma cells.

Silicon dioxide (SiO2) and zinc oxide (ZnO) nanoparticles are widely used in various applications, raising issues regarding the possible adverse effects of these metal oxide nanoparticles on human cells. In this study, we determined the cytotoxic effects of differently charged SiO2 and ZnO nanoparticles, with mean sizes of either 100 or 20 nm, on the U373MG human glioblastoma cell line. The overall cytotoxicity of ZnO nanoparticles against U373MG cells was significantly higher than that of SiO2 nanoparticles.

Assessment of ZnO and SiO2 nanoparticle permeability through and toxicity to the blood-brain barrier using Evans blue and TEM.

As increasing variants of nanoparticles (NPs) are being used in various products, it has become apparent that size alone can no longer adequately explain the variety of generated toxic profiles. Recent studies with NPs have suggested that various sizes of NPs could determine in vitro toxicity. In an attempt to address concerns regarding neurotoxicity of zinc oxide (ZnO) and silica (SiO2) NPs, these were examined after exposing them via oral, dermal, and intravenous administrations of NPs and their toxicological effects on the brain over a prescribed period of time were assessed.

Analysis of zinc oxide nanoparticles binding proteins in rat blood and brain homogenate.

Nanoparticles (NPs) are currently used in chemical, cosmetic, pharmaceutical, and electronic products. Nevertheless, limited safety information is available for many NPs, especially in terms of their interactions with various binding proteins, leading to potential toxic effects. Zinc oxide (ZnO) NPs are included in the formulation of new products, such as adhesives, batteries, ceramics, cosmetics, cement, glass, ointments, paints, pigments, and supplementary foods, resulting in increased human exposures to ZnO.

Analysis of SiO2 nanoparticles binding proteins in rat blood and brain homogenate.

A multitude of nanoparticles, such as titanium oxide (TiO2), zinc oxide, aluminum oxide, gold oxide, silver oxide, iron oxide, and silica oxide, are found in many chemical, cosmetic, pharmaceutical, and electronic products. Recently, SiO2 nanoparticles were shown to have an inert toxicity profile and no association with an irreversible toxicological change in animal models. Hence, exposure to SiO2 nanoparticles is on the increase.

Immunotoxicity of zinc oxide nanoparticles with different size and electrostatic charge.

While zinc oxide (ZnO) nanoparticles (NPs) have been recognized to have promising applications in biomedicine, their immunotoxicity has been inconsistent and even contradictory. To address this issue, we investigated whether ZnO NPs with different size (20 or 100 nm) and electrostatic charge (positive or negative) would cause immunotoxicity in vitro and in vivo, and explored their underlying molecular mechanism. Using Raw 264.

Immunotoxicity of silicon dioxide nanoparticles with different sizes and electrostatic charge.

Silicon dioxide (SiO2) nanoparticles (NPs) have been widely used in the biomedical field, such as in drug delivery and gene therapy. However, little is known about the biological effects and potential hazards of SiO2. Herein, the colloidal SiO2 NPs with two different sizes (20 nm and 100 nm) and different charges (L-arginine modified: SiO2 (EN20[R]), SiO2 (EN100[R]); and negative: SiO2 (EN20[-]), SiO2 (EN100[-]) were orally administered (750 mg/kg/day) in female C57BL/6 mice for 14 days.

Undetactable levels of genotoxicity of SiO2 nanoparticles in in vitro and in vivo tests.

Background: Silica dioxide (SiO2) has been used in various industrial products, including paints and coatings, plastics, synthetic rubbers, and adhesives. Several studies have investigated the genotoxic effects of SiO2; however, the results remain controversial due to variations in the evaluation methods applied in determining its physicochemical properties. Thus, well characterized chemicals and standardized methods are needed for better assessment of the genotoxicity of nanoparticles.

Prenatal development toxicity study of zinc oxide nanoparticles in rats.

This study investigated the potential adverse effects of zinc oxide nanoparticles ([ZnO(SM20(+)) NPs] zinc oxide nanoparticles, positively charged, 20 nm) on pregnant dams and embryo-fetal development after maternal exposure over the period of gestational days 5-19 with Sprague-Dawley rats. ZnO(SM20(+)) NPs were administered to pregnant rats by gavage at 0, 100, 200, and 400 mg/kg/day. All dams were subjected to a cesarean section on gestational day 20, and all of the fetuses were examined for external, visceral, and skeletal alterations.

Effect of zinc oxide nanoparticles on dams and embryo-fetal development in rats.

This study investigated the potential adverse effects of zinc oxide nanoparticles (ZnO(SM20[-]) NPs; negatively charged, 20 nm) on pregnant dams and embryo-fetal development after maternal exposure over the period of gestational days 5-19 with Sprague Dawley rats. ZnO(SM20(-)) NPs were administered to pregnant rats by gavage at 0 mg/kg/day, 100 mg/kg/day, 200 mg/kg/day, and 400 mg/kg/day. All dams were subjected to caesarean section on gestational day 20, and all the fetuses were examined for external, visceral, and skeletal alterations.

Zinc oxide nanoparticles: a 90-day repeated-dose dermal toxicity study in rats.

Zinc oxide (ZnO) works as a long-lasting, broad-spectrum physical sunblock, and can prevent skin cancer, sunburn, and photoaging. Nanosized ZnO particles are used often in sunscreens due to consumer preference over larger sizes, which appear opaque when dermally applied. Although the US Food and Drug Administration approved the use of nanoparticles (NPs) in sunscreens in 1999, there are ongoing safety concerns.

Evaluation of silica nanoparticle toxicity after topical exposure for 90 days.

Silica is a very common material that can be found in both crystalline and amorphous forms. Well-known toxicities of the lung can occur after exposure to the crystalline form of silica. However, the toxicities of the amorphous form of silica have not been thoroughly studied.

Toxicity of 100 nm zinc oxide nanoparticles: a report of 90-day repeated oral administration in Sprague Dawley rats.

Nanoparticles (NPs) are used commercially in health and fitness fields, but information about the toxicity and mechanisms underlying the toxic effects of NPs is still very limited. The aim of this study is to investigate the toxic effect(s) of 100 nm negatively (ZnO(AE100[-])) or positively (ZnO(AE100[+])) charged zinc oxide (ZnO) NPs administered by gavage in Sprague Dawley rats, to establish a no observed adverse effect level, and to identify target organ(s). After verification of the primary particle size, morphology, hydrodynamic size, and zeta potential of each test article, we performed a 90-day study according to Organisation for Economic Co-operation and Development test guideline 408.

A 90-day study of subchronic oral toxicity of 20 nm, negatively charged zinc oxide nanoparticles in Sprague Dawley rats.

Purpose: The widespread use of nanoparticles (NPs) in industrial and biomedical applications has prompted growing concern regarding their potential toxicity and impact on human health. This study therefore investigated the subchronic, systemic oral toxicity and no-observed-adverse-effect level (NOAEL) of 20 nm, negatively charged zinc oxide (ZnO(SM20(-))) NPs in Sprague Dawley rats for 90 days.

Methods: The high-dose NP level was set at 500 mg/kg of bodyweight, and the mid- and low-dose levels were set at 250 and 125 mg/kg, respectively.

Physicochemical properties of surface charge-modified ZnO nanoparticles with different particle sizes.

In this study, four types of standardized ZnO nanoparticles were prepared for assessment of their potential biological risk. Powder-phased ZnO nanoparticles with different particle sizes (20 nm and 100 nm) were coated with citrate or L-serine to induce a negative or positive surface charge, respectively. The four types of coated ZnO nanoparticles were subjected to physicochemical evaluation according to the guidelines published by the Organisation for Economic Cooperation and Development.

Comparative analysis of nanotechnology awareness in consumers and experts in South Korea.

Purpose: This study examined the need for public communication about nanotechnologies and nanoparticles by providing a comparative analysis of the differences in risk awareness of nanotechnologies and nanoparticles between consumers and experts.

Methods: A total of 1,007 consumers and 150 experts participated in this study. A questionnaire was prepared examining their awareness of nanotechnologies and nanomaterials and their view of the necessity for information and education about the latest nanotechnologies and nanomaterials.

Interactive survey of consumer awareness of nanotechnologies and nanoparticles in consumer products in South Korea.

Background: The purpose of our study was to understand consumers' risk awareness and need for relevant information about nanotechnology and nanoparticles contained in products currently being sold in Korea.

Methods: One thousand and seven adult consumers (aged 20-50 years) were randomly selected from all over South Korea between November 1 and 9, 2010. We surveyed the origin and degree of their concern and their need for information and education regarding nanomaterials.

Organization of research team for nano-associated safety assessment in effort to study nanotoxicology of zinc oxide and silica nanoparticles.

Currently, products made with nanomaterials are used widely, especially in biology, bio-technologies, and medical areas. However, limited investigations on potential toxicities of nanomaterials are available. Hence, diverse and systemic toxicological data with new methods for nanomaterials are needed.