Directional Drug Transport through Membrane-Supported Monolayers of Human Liver-Derived Cell Lines.

The aim of this work is to develop a new assay system for screening biliary excretion drugs. When monolayers of human liver-derived cell lines HepG2 and Huh-7 were grown on an insert membrane, the efflux ratio (ER: ratio of the apparent permeability coefficient in the basal-to-apical direction (Papp,B-to-A) to that in the apical to basal direction (Papp,A-to-B)) of sulfobromophthalein (BSP), a model substrate of multidrug resistance-associated protein 2 (MRP2), was greater than 1.0, indicating transport of BSP in the efflux direction. The efflux transport was significantly suppressed by MK-571, an inhibitor of MRPs, in both cell lines. Expression of MRP2 mRNA in HepG2 and Huh-7 was 3.5- and 1.4-fold higher, respectively, than in primary human hepatocytes, while expression of P-glycoprotein and breast cancer resistance protein mRNAs was markedly lower, supporting the idea that MRP2 is the main mediator of directional BSP transport in this assay system. The advantage of our system is the potential to quantitatively evaluate biliary excretion of MRP2 substrates in vitro.

Evaluation of Analytical Precision of Polychromatic Simultaneous WDXRF Spectrometer and Application to Valence Analysis of Cathode Materials of Lithium-Ion Batteries.

A polychromatic simultaneous wavelength-dispersive X-ray fluorescence (PS-WDXRF) spectrometer can measure the valence changes of 3d transition metals with high precision in the laboratory. Adjustment and maintenance of the drive mechanism are unnecessary, and high-precision measurements are possible in a short time because the optical system has no moving parts and is compact. We have developed a PS-WDXRF spectrometer with improved analytical precision that can measure simultaneously the valence changes of three main elements, Mn, Co, and Ni, which are used as cathode materials in Li-ion batteries (LIBs). In this study, the analytical precision of the spectrometer is evaluated, and its precision is confirmed with actual battery cathodes. The identification precision of the fluorescent X-ray peak energy is <0.015 eV, and the valence identification precision is obtained to be <0.06. LiNi0.5Co0.2Mn0.3O2 (NCM523)-based LIB cathodes are analyzed under conditions maintaining this precision, and the valence changes of the 3d transition metals in NCM523 during charging and discharging are found to be 0.68 for Ni, 0.19 for Co, and 0.08 for Mn. These results indicate that Ni contributes the most to the redox process in NCM523-based LIBs, Co contributes slightly, and Mn does not contribute.

Relationship between Self-Rated Health and Lifestyle and Food Habits in Japanese High School Students.

Self-rated health (SRH), a subjective assessment of health status, is extensively used in the field of public health. It is an important and valid measure that is strongly related to morbidity, mortality, longevity and health status. Adolescence is a crucial period for the formation of health status, because health-risk behaviours (e.g., skipping breakfast) are often established during this period. In this study, we investigated the relationship of SRH with lifestyle and eating habits in Japanese high school students. In this study, 1296 students aged 16-18 years from 11 high schools in Japan participated. A questionnaire was administered to these participants that included a question on SRH, five questions on demographic characteristics, six questions on lifestyle items (e.g., wake-up time), five questions on miscellaneous health issues (e.g., anorexia), and 25 questions on food habits and attitudes towards food. We examined the differences between self-rated healthy and unhealthy groups using logistic regression analysis adjusted for gender and age. A dichotomy regression analysis was performed using a stepwise elimination method. Of the 1296 respondents, 16.7% reported feeling unhealthy, 57.7% of whom were females. The self-rated healthy group had a higher frequency of eating breakfast (odds ratio (OR): 2.13; confidence interval (CI): 1.07-4.24) and liked home meals to a greater extent (OR: 3.12; CI: 1.27-7.65) than the self-rated unhealthy group. The two groups did not differ significantly in terms of other lifestyle factors or unidentified complaints. Our results suggest that liking home meals during adolescence may lead to the development of good eating habits, i.e., eating breakfast, and better SRH.

Kerr-induced controllable adiabatic frequency conversion in an ultrahigh Q silica toroid microcavity.

In this Letter, we report, based on our knowledge, the first demonstration of Kerr-induced adiabatic frequency conversion in a silica toroid microcavity. Taking advantage of the instantaneous response of the Kerr effect, we achieved adiabatic frequency conversion with a controllable amount of frequency shift and time width. In addition, thanks to the combination of the Kerr effect and the ultrahigh Q (>107) of the silica toroid microcavity, we also observed multiple frequency conversion within a photon lifetime. Furthermore, use of the Kerr effect allowed us to investigate the influence of the relative phase between the original and converted light.

NaCl ion detection using a silica toroid microcavity.

An optical-microcavity-based sensor is an important building block for an optofluidics system, because it allows us to fabricate small devices with high sensitivity. Here we describe the detection of NaCl and pH in water using a silica toroid microcavity. First we demonstrate the detection of NaCl particles, and show that a detection sensitivity of 0.38 mM is possible with a sample volume of 0.03 nl. Then, we report the detection of NaCl ions in liquid and demonstrate a sensitivity of 3.20 mM and also, in principle, the detection of pH with a sensitivity of 0.14 pH. Finally, we integrate a tapered optical fiber, a silica toroid microcavity, and a fluidic channel for future optofluidics applications.

Increased levels of a particular phosphatidylcholine species in senescent human dermal fibroblasts in vitro.

Plasma membranes are essential components of living cells, and phospholipids are major components of cellular membranes. Here, we used liquid chromatography/mass spectrometry to investigate changes in the membrane phospholipid content that occur in association with aging. Our results indicate that the levels of a particular species of phosphatidylcholine comprised of stearic acid and arachidonic acid increased with age. To determine the reason for the increased levels of this particular phosphatidylcholine, we examined the effect of highly unsaturated fatty acids, such as arachidonic acid and eicosapentaenoic acid, on cellular aging. Applied arachidonic acid was incorporated into phosphatidylcholine molecules, but neither arachidonic acid nor other related unsaturated fatty acids had any effect. We conclude that increased levels of this distinctive phosphatidylcholine are a result of in vitro senescence.

Protective effects of an antioxidant derived from serine and vitamin B6 on skin photoaging in hairless mice.

The generation of reactive oxygen species (ROS) by ultraviolet radiation (UVR) accelerates skin aging, which is known as photoaging. Because cutaneous iron catalyzes ROS generation, sequestering iron by chelating agents is thought to be an effective approach toward preventing photoaging. Previously, N-(4-pyridoxylmethylene)-l-serine (PYSer) was designed as an antioxidant to suppress iron-catalyzed ROS generation by its iron-sequestering activity. In this study, PYSer showed protective effects against skin damage in hairless mice irradiated with ultraviolet B (UV-B). Topical application of PYSer to the skin significantly delayed and/or decreased the visible wrinkle formation induced by chronic UV-B irradiation. A histological study indicated that UV-B-induced epidermal hypertrophy and lymphocytic infiltration were suppressed by PYSer. Moreover, PYSer showed suppressive activity against the UV-B-induced increase in glycosaminoglycans (GAG). These results indicate that PYSer is a promising antioxidant for the prevention of chronic skin photoaging by its iron-sequestering activity.