Anti-Graying Effects of External and Internal Treatments with Luteolin on Hair in Model Mice.

Little is known about the anti-graying effects of antioxidants on hair. The anti-graying effects of three antioxidants (luteolin, hesperetin, and diosmetin) on hair were investigated according to the sequential processes of hair graying that were previously clarified in model mice [Ednrb(+/-);RET-mice]. External treatment with luteolin, but not that with hesperetin or diosmetin, alleviated hair graying in Ednrb(+/-);RET-mice.

Elevated arsenic level in fasting serum via ingestion of fish meat increased the risk of hypertension in humans and mice.

Aims: There has been a shortage of human studies to elucidate the association between serum arsenic levels and the prevalence of hypertension. This study multidirectionally investigated associations among arsenic exposure, dietary ingestion, and the risk of hypertension by combined human epidemiological and mouse experimental studies.

Methods And Results: This study focused on the total arsenic level in fasting serum, a biomarker of arsenic exposure.

Calcitriol inhibits arsenic-promoted tumorigenesis through regulation of arsenic-uptake in a human keratinocyte cell line.

Chronic arsenic exposure from drinking water causes a variety of diseases and it is now recognized that at least 140 million people in 50 countries have been drinking water containing arsenic at levels above the WHO provisional guideline value of 10 μg/L. Long-term exposure to arsenic is associated with various types of cancers in humans including skin cancers. However, there is limited information on key molecules regulating arsenic-promoted carcinogenesis, and methods for the prevention and therapy of arsenic-promoted carcinogenesis have not yet been fully developed.

Stabilization of β-catenin promotes melanocyte specification at the expense of the Schwann cell lineage.

The canonical Wnt/β-catenin pathway governs a multitude of developmental processes in various cell lineages, including the melanocyte lineage. Indeed, β-catenin regulates transcription of Mitf-M, the master regulator of this lineage. The first wave of melanocytes to colonize the skin is directly derived from neural crest cells, whereas the second wave of melanocytes is derived from Schwann cell precursors (SCPs).

Loss-of-function mutation of c-Ret causes cerebellar hypoplasia in mice with Hirschsprung disease and Down's syndrome.

The c-RET proto-oncogene encodes a receptor-tyrosine kinase. Loss-of-function mutations of RET have been shown to be associated with Hirschsprung disease and Down's syndrome (HSCR-DS) in humans. DS is known to involve cerebellar hypoplasia, which is characterized by reduced cerebellar size.

Propofol infusions using a human target controlled infusion (TCI) pump in chimpanzees (Pan troglodytes).

Chimpanzees are genetically and physiologically similar to humans. Several pharmacokinetic models of propofol are available and target controlled infusion (TCI) of propofol is established in humans, but not in chimpanzees. The purpose of this study was to investigate if human pharmacokinetic models can accurately predict propofol plasma concentration (Cp) in chimpanzees and if it is feasible to perform TCI in chimpanzees.

Hair graying with aging in mice carrying oncogenic RET.

Hair graying is a representative sign of aging in animals and humans. However, the mechanism for hair graying with aging remains largely unknown. In this study, we found that the microscopic appearance of hair follicles without melanocyte stem cells (MSCs) and descendant melanocytes as well as macroscopic appearances of hair graying in RET-transgenic mice carrying RET oncogene (RET-mice) are in accordance with previously reported results for hair graying in humans.

Pharmacokinetics and effects on clinical and physiological parameters following a single bolus dose of propofol in common marmosets (Callithrix jacchus).

The objectives of this study were (a) to establish a population pharmacokinetic model and (b) to investigate the clinical and physiological effects of a single bolus dose of propofol in common marmosets. In Study 1, pharmacokinetic analysis was performed in six marmosets under sevoflurane anaesthesia. 8 mg/kg of propofol was administrated at a rate of 4 mg kg  min .

Increased levels of renal damage biomarkers caused by excess exposure to trivalent chromium in workers in tanneries.

Background: The process for leather material production is carried out in developing countries using a large amount of trivalent chromium [Cr(III)]. Assesment of health risks for millions of workers in tanneries worldwide that are highly polluted with Cr(III) is needed.

Methods: Levels of total Cr and its chemical species in wastewater samples from tannery built-up areas of Bangladesh were investigated.

Multidisciplinary approach to assess the toxicities of arsenic and barium in drinking water.

Well water could be a stable source of drinking water. Recently, the use of well water as drinking water has been encouraged in developing countries. However, many kinds of disorders caused by toxic elements in well drinking water have been reported.

Peptides containing the MXXCW motif inhibit oncogenic RET kinase activity with a novel mechanism of action.

REarranged during Transition (RET) is a tyrosine kinase associated with the development of several malignancies. Identification of RET kinase inhibitors promises valuable therapeutic tools for the intervention of RET-driven tumors. Most currently available tyrosine kinase inhibitors target the ATP binding site, but there are several drawbacks of these ATP-competitive drugs.

A unique system that can sensitively assess the risk of chemical leukoderma by using murine tail skin.

Chemical leukoderma is a patchy hypopigmentation in the skin. Phenol derivatives such as raspberry ketone have been reported to cause the development of occupationally induced leukoderma. Recently, 2% (w/w) rhododenol, a reduced form of raspberry ketone used in a skin-lightning agent, also caused the development of leukoderma in >16,000 users, about 2% of all users, in Asian countries including Japan.

Hearing loss in humans drinking tube well water with high levels of iron in arsenic-polluted area.

Well water for drinking with increased levels of iron in arsenic-polluted areas has been reported worldwide. Oral exposure to arsenic has been shown to be associated with hearing loss, while there is no evidence for an association between excessive exposure to iron and hearing loss in humans. In this study, we determined iron and arsenic levels in biological samples and hearing levels by pure tone audiometry (PTA) in subjects in a control area and an arsenic-polluted area in Bangladesh.

Chromium-mediated hyperpigmentation of skin in male tannery workers in Bangladesh.

Since tannery workers in developing countries are chronically exposed to high levels of chromium (Cr), there are serious concerns about health problems. However, there has been limited study in which Cr levels were measured in tannery workers, who are chronically exposed to Cr. Our preliminary inspection showed that there was hyperpigmented skin in tannery workers.

Inhibition of mast cell degranulation by melanin.

Melanin is a dark naturally occurring pigment produced in nature and in many organisms. Although several reports have demonstrated applications for melanins in various therapeutic treatments, to date, no research has examined the anti-allergic effect of melanin. In this study, we for the first time found that solubilized or synthesized soluble melanin acts as a potent inhibitor of the degranulation of mast cells.

Label-Free Imaging of Melanoma with Confocal Photothermal Microscopy: Differentiation between Malignant and Benign Tissue.

Label-free confocal photothermal (CPT) microscopy was utilized for the first time to investigate malignancy in mouse skin cells. Laser diodes (LDs) with 405 nm or 488 nm wavelengths were used as pumps, and a 638 nm LD was used as a probe for the CPT microscope. A Grey Level Cooccurrence Matrix (GLCM) for texture analysis was applied to the CPT images.

A disadvantageous effect of adsorption of barium by melanin on transforming activity.

At present, beneficial effects of melanin and harmful effects of barium have been reported. However, little is known about the adsorption of barium, and even less is known about the biological significance of adsorption of barium by melanin. In this study, we showed that there was a strong correlation between the digitalized level of skin pigmentation and barium level in murine skin compared to the correlations between skin pigmentation level and levels of homologous elements of barium (magnesium, calcium and strontium).

Arsenic level in toenails is associated with hearing loss in humans.

Arsenic (As) pollution in drinking water is a worldwide health risk for humans. We previously showed hearing loss in young people who live in areas of As-polluted drinking water and in young mice orally treated with As. In this study, we epidemiologically examined associations between As levels in toenails and hearing in 145 Bangladeshi aged 12-55 years in 2014.

Manganese in toenails is associated with hearing loss at high frequencies in humans.

Purpose: Elevated hearing thresholds from high frequencies are known to be one of the hallmarks of age-related hearing loss. Our recent study showed accumulation of manganese (Mn) in inner ears resulting in acceleration of age-related hearing loss in mice orally exposed to Mn. However, there is no evidence showing an association between Mn in non-invasive biological samples and hearing loss in humans evaluated by pure tone audiometry (PTA).

A comprehensive study including monitoring, assessment of health effects and development of a remediation method for chromium pollution.

Chromium (Cr) pollution caused by wastewater from tanneries is a worldwide environmental problem. To develop a countermeasure, we performed a comprehensive study using Hazaribagh, the tannery area in Dhaka City, Bangladesh, as a model. Our environmental monitoring indicated that the soluble form of Cr, but not barium or arsenic, in Buriganga River is derived from Hazaribagh.

Increased expression level of Hsp70 in the inner ears of mice by exposure to low frequency noise.

Previous studies showed that people in urban areas are possibly exposed to 60-110 dB of low frequency noise (LFN) defined as noise of ≤100 Hz in their daily life. Previous studies also showed increased health risks by exposure to high levels (130-140 dB) of LFN in animals. However, little is known about the health effects of exposure to an ordinary level of LFN.

Janus-Type Gold/Polythiophene Composites Formed via Redox Reaction at the Ionic Liquid|Water Interface.

Janus-type Au/polythiophene (PT) composites have been prepared by utilizing the liquid/liquid interface between water (W) and a hydrophobic ionic liquid (IL) as the redox reaction site. AuCl is reductively deposited, and terthiophene is oxidatively polymerized spacio-selectively at the IL|W interface, leading to the formation of the Au/PT composites. The composites are Janus-type Au-attached PT plates with two surface morphologies, flat surface and flowerlike surface at the W and IL sides of the plates at the IL|W interface, respectively.

Oral exposure to arsenic causes hearing loss in young people aged 12-29 years and in young mice.

There is no information on the association between oral exposure to arsenic (As) and hearing loss in humans or mice. In this combined epidemiological study and experimental study, the association of oral exposure to As with hearing loss in people aged 12-29 years and young mice was examined. Subjects in the exposure group (n = 48), who were drinking tube well water contaminated with As, showed significantly higher risks of hearing loss at 4 kHz [odds ratio (OR) = 7.

Manganese-Mediated Decrease in Levels of c-RET and Tyrosine Hydroxylase Expression In Vitro.

Previous studies showed that overexposure to manganese causes parkinsonism, a disorder of dopaminergic neurons. Previous studies also showed that activity of c-RET kinase controls dopamine production through regulation of tyrosine hydroxylase (TH) expression, suggesting the involvement of c-RET in the development of parkinsonism. To our knowledge, however, there is no report showing a correlation between manganese-mediated parkinsonism and c-RET.