Skin Electrical Impedance Model for Evaluation of the Thickness and Water Content of the Stratum Corneum

Deterioration of the skin barrier function causes symptoms such as allergies because various chemical substances may enter the human body. Quantitative evaluation of the thickness and water content of the stratum corneum is useful as a measure of the skin barrier function in domains such as dermatology, nursing science, and cosmetics development. The stratum corneum is responsible for most of the skin barrier function, and two factors—the thickness and water content of the stratum corneum—are thus important. In this paper, the stratum corneum is regarded as a parallel model of resistance and capacitance. From measurements of the electrical impedance of the skin, we propose a new model for simultaneous estimation of the thickness and water content of the stratum corneum conventionally measured by a confocal laser scanning microscope and a confocal Raman spectrometer, respectively, and we discuss the results of the measurements. The electrical impedance of the skin was measured using a device that we developed. The measurement began 3 seconds after the electrodes on the measurement head of the device came into contact with the skin, and parameters including the impedance, which was obtained by applying an alternating current signal at two frequencies, were measured. We measured the thickness and water content of the stratum corneum using confocal laser microscopy and confocal Raman spectroscopy, respectively; investigated the relationship of the thickness and water content of the stratum corneum with the electrical impedance of the skin; and established a new potential model for estimating the thickness and water content of the stratum corneum from the parallel resistance and capacitance. The correlation coefficients of the verification data were 0.931 and 0.776, respectively; and the root-mean-squared error of the thickness of the stratum corneum was 2.3 µm, while the root-mean-squared error of the water content at the surface of the stratum corneum was 5.4 points. These findings indicate the feasibility of quantitative evaluation of the thickness and water content of the stratum corneum by measuring skin electrical impedance

Efficacy and Safety of an Ultrasonically Activated Device for Sealing the Bile Ducts During Liver Resection

The use of ultrasonically activated devices (USADs) in hepatic resections may be associated with an increased rate of complications, such as postoperative bile leaks. Nonetheless, the safety of USADs for sealing bile ducts during liver surgery has not yet been established. The purpose of this study was to assess the efficacy of a USAD for sealing bile ducts. In animal experiments, the common bile duct of ten anesthetized dogs was individually occluded using a USAD. Additionally, using the prospective liver surgery database from a single institution, we identified 45 consecutive patients who underwent hepatic resection using a USAD (USAD group) and 45 similar patients who underwent hepatic resection without the use of a USAD (NUSAD group). In the occluded and harvested canine bile ducts, the mean burst pressure was 280mmHg, and the lumen of the bile duct was completely sealed morphologically. In the clinical study, there was no significant difference in postoperative mortality or complications between the two groups, and biliary leakage was observed in only one patient (0.7%) in the USAD group. These data demonstrate that the USAD is a safe, efficient, and practical instrument for use during liver surgery to achieve complete hemobiliary stasis

Development of a New Bioartificial Liver Support System Using a Radial-flow Bioreactor

There is an increasing number of patients with severe liver disease that requires whole organ transplantation or living-related split liver transplantation. This has resulted in a shortage of donor organs, which is particularly problematic and still awaits resolution. Bioartificial liver (BAL) support systems have been developed with the aim of supporting patients with life-threatening liver disease until their liver recovers. Here, we describe a high performance three-dimensional rat hepatocyte culture system using a radial-flow bioreactor (RFB) with a polyvinyl alcohol (PVA) membrane as a small-scale BAL support system. Hepatocytes from male Sprague-Dawley rat livers were isolated and divided into two groups as follows. Group A: isolated hepatocytes were maintained in culture medium as controls; and group B: isolated hepatocytes were injected into the medium chamber of the RFB-PVA culture system. Sampling was carried out every 48 h to analyze the concentrations of ammonia and albumin in the medium. Light and electron microscopic examination of hepatocytes explanted from the PVA membrane was also performed. Albumin production and urea synthesis by cells in group B were both significantly higher than in group A. Hematoxylin-Eosin staining of the cells in group B showed that three-dimensional cell masses were attached to the PVA membrane. It also showed that the cells were stably proliferating in the porous spaces of the PVA. Scanning electron microscopic images of group B also showed clusters of hepatocytes attached to the PVA membrane. Hepatocyte clusters growing in the RFB-PVA culture system retained their biological function and were stable in the porous spaces of the PVA membrane. This cell culture system may be useful for the development of new BAL support systems

Vascular RAGE transports oxytocin into the brain to elicit its maternal bonding behaviour in mice

金沢大学医薬保健研究域医学系Oxytocin sets the stage for childbirth by initiating uterine contractions, lactation and maternal bonding behaviours. Mice lacking secreted oxcytocin (Oxt -/-, Cd38 -/-) or its receptor (Oxtr -/-) fail to nurture. Normal maternal behaviour is restored by peripheral oxcytocin replacement in Oxt -/- and Cd38 -/-, but not Oxtr -/- mice, implying that circulating oxcytocin crosses the blood-brain barrier. Exogenous oxcytocin also has behavioural effects in humans. However, circulating polypeptides are typically excluded from the brain. We show that oxcytocin is transported into the brain by receptor for advanced glycation end-products (RAGE) on brain capillary endothelial cells. The increases in oxcytocin in the brain which follow exogenous administration are lost in Ager -/- male mice lacking RAGE, and behaviours characteristic to abnormalities in oxcytocin signalling are recapitulated in Ager -/- mice, including deficits in maternal bonding and hyperactivity. Our findings show that RAGE-mediated transport is critical to the behavioural actions of oxcytocin associated with parenting and social bonding.3082047

A pristine record of outer Solar System materials from asteroid Ryugu’s returned sample

Volatile and organic-rich C-type asteroids may have been one of the main sources of Earth’s water. Our best insight into their chemistry is currently provided by carbonaceous chondritic meteorites, but the meteorite record is biased: only the strongest types survive atmospheric entry and are then modified by interaction with the terrestrial environment. Here we present the results of a detailed bulk and microanalytical study of pristine Ryugu particles, brought to Earth by the Hayabusa2 spacecraft. Ryugu particles display a close compositional match with the chemically unfractionated, but aqueously altered, CI (Ivuna-type) chondrites, which are widely used as a proxy for the bulk Solar System composition. The sample shows an intricate spatial relationship between aliphatic-rich organics and phyllosilicates and indicates maximum temperatures of ~30 °C during aqueous alteration. We find that heavy hydrogen and nitrogen abundances are consistent with an outer Solar System origin. Ryugu particles are the most uncontaminated and unfractionated extraterrestrial materials studied so far, and provide the best available match to the bulk Solar System composition

Colonization of coral rubble by motile cryptic animals: Differences between contiguous versus raised substrates from the bottom

Recent studies have demonstrated that interstices of coral rubble harbor rich and diverse assemblages of motile cryptic animals. Habitats of coral rubble are prone to frequent physical disturbances, so colonization is an important process to maintain the assemblages of these cryptic animals. In order to examine the pattern of colonization, field experiments were carried out using mesh traps with defaunated coral rubble: one treatment placed on the bottom and the other raised 15 cm above the bottom (throughout as "raised") to restrict colonizers to only organisms that are able to invade via the water column. Results of nMDS and PERMANOVA showed significant differences between the assemblages of the bottom and raised treatments. Species-specific variations in the rate of colonization, which were estimated by fitting the von Bertalanffy equation, contributed to the variations in the cryptic assemblages. Generally, decapods and gastropods colonized via the benthic pathway with colonizing individuals moving on the surface of the bottom substrate, while copepods and non-shelled gammarids colonized via the planktonic pathway. Variations in cryptic assemblages in coral rubble microhabitats may be partly due to differences in contributions via the two colonization pathways

PRELIMINARY STUDY TO PREVENT INCIDENTAL CAPTURE OF SEA TURTLES BY POUND NET

Southeast Asia Sea Turtle Associative ResearchBangkok, Thailand, 16-19 December 2002To mitigate incidental catch of sea turtles by pound net fishery, we tested the efficiency of the specially designed pocket nets to release turtles selectively. The experiments were carried out using a pound net in operation in a lagoon of Ishigaki Island, southernmost Japan. Immature green turtles, Chelonia mydas, were put into the pocket net and their behaviors were captured with underwater video. The turtles showed back and forth motion in the pocket net between two funnels or between the funnel and the cod-end. An escape hatch with a flap was equipped above the base of the funnels on the pocket net. Three designs of the escape hatch were examined. Using these gears, unintended capture of sea turtles by pound net is expected to reduce by about 60 %