In vivo genotoxicity of high-intensity intermediate frequency magnetic fields in somatic cells and germ cells.

Intermediate frequency magnetic fields (IF-MFs) at ~85 kHz are one of the components of wireless power transfer (WPT) systems. However, the available data needed for the assessment of the safety of organisms from IF-MF exposure are scarce. Thus, there is an imminent need to accumulate evidence-based assessment data. In particular, if humans are exposed to IF-MF due to an accident or trouble, they are at increased risk of being exposed to high-intensity IF-MF within a short period. The already existing exposure system was improved to a system that could intermittently expose animals at 3 s intervals. This system allows the exposure of a mouse to high-intensity IF-MF (frequency: 82.3 kHz; induced electric field: 87 V/m, which was 3.8 times the basic restriction level for occupational exposure in the ICNIRP guideline), while regulating the heat generated by the coil. In vivo genotoxicity after IF-MF exposure was assessed using micronucleus (MN) test, Pig-a assay, and gpt assay. The results of MN test and Pig-a assay in hematopoietic cells revealed that neither the reticulocytes nor the mature erythrocytes exhibited significant increases in the IF-MF-exposed group compared with that in the sham-exposed group. In germ cells, MN test and gpt assay outcomes showed that IF-MF exposure did not cause any genetic or chromosomal abnormality. Based on these data, there was no genotoxic effect of our set IF-MF exposure on somatic and germ cells. These findings can contribute to the widespread use of WPT systems as effective data of IF-MF safety assessment.

Exposure to Heated Tobacco Products Aerosol Causes Acute Stress Responses in the Lung of Mouse.

In the present study, we evaluated the acute response of mice exposed to IQOS aerosol, a brand-name heated tobacco product (HTP), in the lung tissue. First, the thiobarbituric acid-reactive substances (TBA-RS) value was measured as an index to assess oxidative stress, and a significant increase was observed after exposure, followed by a significant increase in the total lung GSH concentration. The stress responses induced by IQOS aerosols was then analyzed by focusing on the changes in Nrf2 and ATF4, which are transcription factors that induce the expression of genes involved in GSH biosynthesis or metabolism. Although Nrf2 activation was not observed, significant accumulation of ATF4 in the nuclear fraction was noted three hours after exposure to IQOS aerosols. Upon an examination of changes in factors in the GSH biosynthetic system, a significant increase in cystine concentration in the lung tissue was measured, and an increase in xCT expression level was observed in the cell membrane fraction three-six hours after IQOS exposure. Furthermore, characteristic changes in HO-1, a stress-response protein regulated by ATF4, was discovered six hours after IQOS exposure. Moreover, analysis of the upstream ATF4 regulatory system revealed that phosphorylation of eIF2α was enhanced in the lung cytoplasmic fraction three hours after exposure to IQOS aerosols. These findings suggest that ER stress might be induced as an early response to IQOS aerosol exposure, accompanied by the activation of the eIF2α-ATF4 axis. These intracellular changes have also been reported after exposure to combustible cigarette smoke. Thus, the acute response found in the lungs of mice in the present study demonstrate that the inhalation of aerosols from IQOS elicits a biological response similar to that of combustible cigarette smoke. In conclusion, our results provide evidence that the biological effects of HTPs, such as IQOS, cannot be ignored in the lungs.

Increased oxidative stress and effects on inflammatory cytokine secretion by heated tobacco products aerosol exposure to mice.

Although the amount of chemicals in heated tobacco products (HTPs) aerosols is reduced compared to conventional combustible cigarette smoke, the association between HTPs and reduced health effects remains unclear. In this study, we hypothesized that exposure to IQOS, an HTP, would increase oxidative stress and affect the secretion of inflammatory cytokines. First, C57BL/6 mice exposed to IQOS aerosols were evaluated to determine the adverse effects of IQOS exposure. IQOS exposure significantly decreased the concentration of GSH in alveolar macrophages in a dose-dependent manner and increased the percentage of GSSG in lung tissues. These results indicate that IQOS exposure increases oxidative stress, and GSH is consumed to remove oxidative stress. In addition, foamy alveolar macrophages were observed in the bronchial alveolar lavage fluid after IQOS exposure. Although the concentration of inflammatory cytokines, IL-6, and GM-CSF, in the plasma increased significantly after IQOS exposure, there were no significant changes in other cytokines. These results indicate that short-term exposure to IQOS aerosols may increase oxidative stress and induce the secretion of inflammatory cytokines. Lastly, the longer-term effects of IQOS aerosols exposure should be evaluated in the future.

A Newly Developed Aerosol Exposure Apparatus for Heated Tobacco Products for In Vivo Experiments Can Deliver Both Particles and Gas Phase With High Recovery and Depicts the Time-Dependent Variation in Nicotine Metabolites in Mouse Urine.

INTRODUCTION: There is no standardized aerosol exposure apparatus to deliver heated tobacco products (HTPs) for in vivo experiments. Therefore, we developed a novel HTPs aerosol exposure apparatus for mice and demonstrated that nicotine and other chemicals in HTPs aerosol generated by the apparatus can be delivered to mice which replicate human smoke. AIMS AND METHODS: The amounts of nicotine, tar, and carbon monoxide (CO) in IQOS (Marlboro Regular HeatSticks) aerosol generated by two types of apparatuses were determined. C57BL/6N mice were exposed to IQOS aerosol, followed by determination of the urinary nicotine metabolites. Further, the skin surface temperature of mice was monitored to confirm the vasoconstriction action of nicotine. RESULTS: The amount of chemicals in IQOS aerosol by the novel air push-in inhalation apparatus for HTPs (APIA) was equivalent to that of the analytical vaping machine (LM4E) (1.60 ± 0.08 [APIA] vs. 1.46 ± 0.07 mg/stick [LM4E] in nicotine and 0.55 ± 0.04 [APIA] vs. 0.45 ± 0.01 mg/stick [LM4E] in CO). After mice were exposed to IQOS aerosol by APIA, the urinary nicotine metabolite levels were determined; peak values in cotinine and 3-hydroxycotinine (3-HC) were 6.82 µg/mg creatinine at 1 hour after exposure and 32.9 µg/mg creatinine at 2 hours after exposure, respectively. The skin surface temperature decreased and was lower (33.5°C ± 0.5°C) at 30 minutes than before exposure (37.6°C ± 0.8°C). CONCLUSIONS: The new apparatus for HTPs aerosol exposure to mice showed good performances in terms of both chemical analysis of collected aerosol and fluctuations in the urinary nicotine metabolites. IMPLICATIONS: The APIA reported in this study can expose small animals to HTPs aerosol, including nicotine and other chemical substances as same amounts as LM4E and replicate actual human smoking process by in vivo experiments. Therefore, the experiments using APIA can provide evidence to assess the health risks of HTPs use.

No evidence for genotoxicity in mice due to exposure to intermediate-frequency magnetic fields used for wireless power-transfer systems.

Time varying magnetic fields (MFs) are used for the wireless power-transfer (WPT) technology. Especially, 85 kHz band MFs, which are included in the intermediate frequency (IF) band (300 Hz - 10 MHz), are commonly used WPT system for charging electric vehicles. Those applications of WPT technology have elicited public concern about health effects of IF-MF. However, existing data from health risk assessments are insufficient and additional data are needed. We assessed the genotoxic effects of IF-MF exposure on erythroid differentiation in mice. A high-intensity IF-MF mouse exposure system was constructed to induce an average whole-body electric field of 54.1 V/m. Blood samples were obtained from male mice before and after a 2-week IF-MF exposure (1 h/day, total: 10 h); X-irradiated mice were used as positive controls. We analyzed the blood samples with the micronucleus (MN) test and the Pig-a mutation assay. No significant differences were seen between IF-MF-exposed and sham-exposed mice in the frequencies of either MN or Pig-a mutations in mature erythrocytes and reticulocytes. IF-MF exposure did not induce genotoxicity in vivo under the study conditions (2.36× the basic restriction for occupational exposure, 22.9 V/m, in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines). The absence of significant biological effects due to IF-MF exposure supports the practical application of this technology.

[A Case of Myeloid Sarcoma in the Small Intestine Presenting with Intussusception].

A sixty-something man presented with lower abdominal pain in early Y month 20XX, and was examined at the hospital's internal medicine outpatient clinic. An abdominal CT showed a soft tissue mass around the left hip joint, and multiple enlarged lymph nodes from inside the pelvis to the mesentery of the abdomen. We noted a small-intestinal intussusception in the lower right abdomen, and suspected malignant lymphoma. We did a CT-guided biopsy on the left hip joint soft tissue mass, and performed surgery on the small-intestinal intussusception. During surgery, we noted an approximately 30 cm ileal intussusception located about 60 cm from the terminal ileum, and enlarged lymph nodes in the nearby mesentery. We removed the ileal intussusception. The pathological diagnosis was myeloid sarcoma, and the soft tissue mass in the left hip joint was also diagnosed as myeloid sarcoma. We performed a bone-marrow biopsy at the hematology department, and diagnosed acute myeloid leukemia M2. We then started remission-induction therapy and consolidation therapy, and the patient was diagnosed as in remission in Y+5 month 20XX. We also need to keep in mind myeloid sarcoma in the intestine as a subtype of acute myeloid leukemia, as malignant tumor in the small intestine presenting with intussusception.

A Case of Primary Colonic Signet Ring Cell Carcinoma in a Young Man which Preoperatively Mimicked Phlebosclerotic Colitis.

A 35-year-old man was referred to our hospital for chronic abdominal pain and diarrhea. Computed tomography showed wall thickening, poor contrast enhancement and calcification of the ascending colon, which were consistent with phlebosclerotic colitis. Malignant character was not detected from a biopsy specimen. Operatively, we observed a scirrhous mass of the ascending colon invading surrounding tissue, which was diagnosed as signet ring cell carcinoma based on analysis of an intraoperative frozen section. Right hemicolectomy with regional lymph node dissection was performed. This case was extremely similar to phlebosclerotic colitis in clinical findings; surgical resection was required for correct diagnosis.

Global Analysis of Transcriptional Expression in Mice Exposed to Intermediate Frequency Magnetic Fields Utilized for Wireless Power Transfer Systems.

BACKGROUND: Intermediate frequency magnetic fields (IF-MFs) at around 85 kHz are a component of wireless power transfer systems used for charging electrical vehicles. However, limited data exist on the potential health effects of IF-MFs. We performed a comprehensive analysis of transcriptional expression in mice after IF-MF exposure. MATERIALS AND METHODS: We developed an IF-MF exposure system to generate a high magnetic flux density (25.3 mT). The system can expose the IF-MF for a mouse whole-body without considering thermal effects. After 10 days (1 h/day) of exposure, a comprehensive expression analysis was performed using microarray data from both the brain and liver. RESULTS: No significant differences in transcriptional expression were detected in the 35,240 probe-sets when controlling the false discovery rate (FDR) under a fold change cutoff >1.5. However, several differential expressions were detected without FDR-adjustment, but these were not confirmed by RT-PCR analysis. CONCLUSIONS: To our knowledge, this is the first in vivo study to evaluate the biological effects of IF-MF exposure with an intense magnetic flux density 253 times higher than the occupational restriction level defined by the International Commission on Non-Ionizing Radiation Protection guidelines. However, our findings indicate that transcriptional responses in the living body are not affected under these conditions.

A Case of Eosinophilic Chronic Rhinosinusitis Associated with Choroidal Folds and Ocular Motility Disorder.

We report a case of eosinophilic chronic rhinosinusitis (ECRS) associated with choroidal folds and ocular motility disorder. A 50-year-old male with rhinosinusitis and bronchial asthma presented with anorthopia of the lower visual field and ocular motility disorder of the left eye. Dilated fundus examination and optical coherence tomography (OCT) revealed wavy choroidal folds in the upper retina. An emergent computed tomography (CT) showed sinusitis, a partial defect of the superior wall of the orbit on the left side, and deformation of the left eye. Based on the clinical findings, the patient was diagnosed with sinusitis complicated by ocular motility disorder. Endoscopic sinus surgery (ESS) was performed. A histopathological examination of the excised polyps showed extensive eosinophil invasion. According to the clinical findings of the nasal polyps, CT images, and peripheral blood tests, he was diagnosed as ECRS. One month after ESS, both ocular movement and anorthopia were improved. The choroidal folds observed using OCT disappeared 2 months after ESS. Although ECRS is rarely associated with ocular complications, bone involvement in sinusitis may result in deformation of the eyeball leading to choroidal folds and ocular motility disorder.

Pneumonia and Extracorporeal Cardiopulmonary Resuscitation Followed by Targeted Temperature Management in Patients With Out-of-Hospital Cardiac Arrest　- Retrospective Cohort Study.

Background: We examined the association between initiation of extracorporeal cardiopulmonary resuscitation (ECPR) and the incidence of infectious complications, such as pneumonia, sepsis, and bacteremia, after out-of-hospital cardiac arrest (OHCA) in patients who received targeted temperature management (TTM). Methods and Results: This retrospective study used data from hospital medical records of patients with OHCA treated with TTM who had been admitted to St. Luke's International Hospital between April 2006 and December 2018. The primary endpoint was the association between the type of CPR and the incidence of early onset pneumonia in the intensive care unit (ICU; between 48 h and 7 days of hospitalization). Univariate and multivariate logistic regression analyses were performed for the primary endpoints. After applying the inclusion/exclusion criteria, 254 patients were included in the analyses; of these, 52 were enrolled in the ECPR group, and 202 were enrolled in the CCPR group. Median age was 58 years, 88.5% were male, prophylactic antibiotics were used in 80.3%, and favorable neurological outcomes were observed in 51.9%. On multivariate analysis, ECPR (odds ratio [OR], 2.78; 95% CI: 1.16-6.66; P=0.037) was significantly associated with the development of early onset pneumonia. Conclusions: ECPR was an independent predictor of pneumonia after OHCA in patients who received TTM.

Exposure to nano-size titanium dioxide causes oxidative damages in human mesothelial cells: The crystal form rather than size of particle contributes to cytotoxicity.

Exposure to nanoparticles such as carbon nanotubes has been shown to cause pleural mesothelioma similar to that caused by asbestos, and has become an environmental health issue. Not only is the percutaneous absorption of nano-size titanium dioxide particles frequently considered problematic, but the possibility of absorption into the body through the pulmonary route is also a concern. Nevertheless, there are few reports of nano-size titanium dioxide particles on respiratory organ exposure and dynamics or on the mechanism of toxicity. In this study, we focused on the morphology as well as the size of titanium dioxide particles. In comparing the effects between nano-size anatase and rutile titanium dioxide on human-derived pleural mesothelial cells, the anatase form was shown to be actively absorbed into cells, producing reactive oxygen species and causing oxidative damage to DNA. In contrast, we showed for the first time that the rutile form is not easily absorbed by cells and, therefore, does not cause oxidative DNA damage and is significantly less damaging to cells. These results suggest that with respect to the toxicity of titanium dioxide particles on human-derived mesothelial cells, the crystal form rather than the particle size has a greater effect on cellular absorption. Also, it was indicated that the difference in absorption is the primary cause of the difference in the toxicity against mesothelial cells.

Exposure time-dependent thermal effects of radiofrequency electromagnetic field exposure on the whole body of rats.

We investigated the thermal effects of radiofrequency electromagnetic fields (RF-EMFs) on the variation in core temperature and gene expression of some stress markers in rats. Sprague-Dawley rats were exposed to 2.14 GHz wideband code division multiple access (W-CDMA) RF signals at a whole-body averaged specific absorption rate (WBA-SAR) of 4 W/kg, which causes behavioral disruption in laboratory animals, and 0.4 W/kg, which is the limit for the occupational exposure set by the International Commission on Non-Ionizing Radiation Protection guideline. It is important to understand the possible in vivo effects derived from RF-EMF exposures at these intensities. Because of inadequate data on real-time core temperature analyses using free-moving animal and the association between stress and thermal effects of RF-EMF exposure, we analyzed the core body temperature under nonanesthetic condition during RF-EMF exposure. The results revealed that the core temperature increased by approximately 1.5°C compared with the baseline and reached a plateau till the end of RF-EMF exposure. Furthermore, we analyzed the gene expression of heat-shock proteins (Hsp) and heat-shock transcription factors (Hsf) family after RF-EMF exposure. At WBA-SAR of 4 W/kg, some Hsp and Hsf gene expression levels were significantly upregulated in the cerebral cortex and cerebellum following exposure for 6 hr/day but were not upregulated after exposure for 3 hr/day. On the other hand, there was no significant change in the core temperature and gene expression at WBA-SAR of 0.4 W/kg. Thus, 2.14-GHz RF-EMF exposure at WBA-SAR of 4 W/kg induced increases in the core temperature and upregulation of some stress markers, particularly in the cerebellum.

New scoring system of an interview for the diagnosis of benign paroxysmal positional vertigo.

Conclusion This study investigated a novel instrument to diagnose benign paroxysmal positional vertigo (BPPV). Objective To develop a new scoring system of an interview for the diagnosis of BPPV. Methods The answers to questions on dizziness and/or vertigo (D/V) (571 patients) were analyzed and the questions for which the answers differed significantly between the patients with and without BPPV were selected. Results This study established an intensive questionnaire with a scoring system. It consists of the following questions: (1) Is rotary vertigo a characteristic of your D/V? (2) Is your D/V triggered when you roll your head over in a supine position? (3) Does your D/V disappear within 5 min? (4) Have you previously experienced hearing loss in one ear, or have you experienced hearing loss, tinnitus, or ear fullness with this D/V? One point each was given to an answer of 'yes' to questions (1) and (2). Two points were given to an answer of 'yes' to question (3). One point was subtracted upon an answer of 'yes' to question (4). When the total score was greater than two points, the patient was diagnosed with BPPV. The sensitivity of the diagnosis of BPPV by this scoring system was 81% and the specificity was 69%.

End-of-life decisions: a survey of the perspectives of people in Korea, China, and Japan / Decisiones al final de la vida: una encuesta sobre las perspectivas de las personas en Corea, China y Japón / Decisões de final-de-vida: uma pesquisa sobre as perspectivas da população na Coreia, China e Japão

Three East Asian countries, Korea, China, and Japan, have shared a similar cultural background throughout history. This is the basis of the assumption of Asian values in the field of bioethics. However, different processes of modernization and healthcare systems have resulted in considerable differences. Along with the aging process, end-of-life care issues have been increasing in importance in these three countries. We conducted a study of 899 lay persons in 3 countries regarding their perspectives about end-of-life decisions; favorable ways of decision-making in end-of-life care; institutional and legal devices; withdrawal of life-sustaining treatment; and euthanasia. We confirmed several similarities and noted some differences among the three countries.

Tres países del Este Asiático, Corea, China y Japón, han compartido una cultura bioética similar. Sin embargo, los procesos diferentes de modernización y los sistemas de cuidado de la salud han resultado en diferencias considerables. Junto con los procesos de envejecimiento, los temas del cuidado al final de la vida han ido creciendo en importancia en estos tres países. Realizamos un estudio con 899 personas legas en los tres países respecto a sus perspectivas sobre decisiones al final de la vida; formas favorables de toma de decisiones en el cuidado al final de la vida; disposiciones institucionales y legales; retirada de tratamiento de sostenimiento vital; y eutanasia. Confirmamos varias similitudes y notamos algunas diferencias entre los tres países.

Três países asiáticos, Coreia, China, e Japão, têm compartilhado uma semelhante formação cultural através da história. Esta é a base da aceitação de valores asiáticos no campo da bioética. Contudo, diferentes processos de modernização e sistemas de cuidado à saúde resultaram em consideráveis diferenças. Ao logo do processo de envelhecimento, temas sobre cuidados no final-de-vida incrementaram em importância nestes três países. Nós conduzimos um estudo em 899 pessoas leigas nos 3 países considerando as suas perspectivas sobre decisões a cerca do final-de-vida; modos favoráveis de tomada de decisão em cuidados de final-de-vida; dispositivos institutionais e legais; suspensão de tratamento de sustentação da vida; e eutanasia. Nós confirmamos inúmeras semelhanças e notamos algumas diferenças entre os três países.

Resolution of gelatinous bone marrow transformation following hormone replacement therapy in a patient with primary insufficiency of the adrenal and thyroid glands.

A 59-year-old man with recurrent oral cancer presented with severe pancytopenia, hyponatremia and hypoglycemia. Endocrine testing showed a partial primary adrenal insufficiency and primary hypothyroidism. The bone marrow biopsy showed a gelatinous transformation with hypocellularity and fat atrophy. His pancytopenia, hyponatremia and hypoglycemia resolved following treatment with corticosteroids and thyroid hormone replacement therapy. The follow-up bone marrow biopsy demonstrated a resolution of the gelatinous transformation. This case is a rare example of a patient with a primary insufficiency of the adrenal and thyroid glands that is associated with gelatinous bone marrow transformation (GMT). The GMT was resolved through the administration of corticosteroids and thyroid hormone replacement therapy.

Human keratinocyte caspase-14 expression is altered in human epidermal 3D models by dexamethasone and by natural products used in cosmetics.

Caspase-14 is a cysteinyl-aspartate-specific proteinase that is specifically expressed in epidermal keratinocytes. Dysregulation of caspase-14 expression is implicated in impaired skin barrier formation. To elucidate the regulation of caspase-14 in differentiated keratinocytes, we characterized the expression of caspase-14 in normal human epidermal keratinocytes (NHEKs) and two types of three-dimensional (3D) human epidermis culture models, EPI-200 and EPI-201, via RT-PCR and immunoblot analyses. Caspase-14 expression was absent in subconfluent NHEKs, but was present in confluent NHEKs as well as those induced to differentiate by calcium. Caspase-14 expression levels in the 3D epidermis models were almost equal to that in the Ca(2+)-treated differentiated NHEKs. Despite the presence of caspase-14 expression in these models, caspase-14 activity was found only in the mature 3D skin model, EPI-200. This was confirmed by detection of a 17 kDa cleaved fragment of caspase-14 present only in the EPI-200 model. Since glucocorticoid (GC) receptor is required for skin barrier competence, we investigated whether the GC dexamethasone (Dex) and various natural components of common skin moisturizers affect caspase-14 expression in keratinocytes. Dex decreased caspase-14 expression in undifferentiated, but not differentiated, NHEKs. Conversely, Dex increased caspase-14 expression in both 3D skin models, although it did not alter caspase protease activity. Similar to treatment with Dex, treatment of the premature 3D skin mode, EPI-201 with a Galactomyces ferment filtrate markedly increased expression of caspase-14. Further, these results suggest that the effect of Dex, or lack thereof, on caspase-14 expression is dependent on the stage of keratinocyte differentiation.

Interferon gamma induces steroid sulfatase expression in human keratinocytes.

Steroid sulfatase (STS) plays an important role in steroid metabolism in which estrogens and dehydroepiandrosterone (DHEA) are produced from their sulfates. However, little is known about the transcriptional regulation of the STS gene in keratinocytes. Since keratinocytes are thought to be a primary target of interferon gamma (IFNγ) in inflammatory and immune responses, we assessed the effects of this cytokine upon STS gene expression in the human keratinocyte cell line SVHK and in normal human keratinocytes (NHEK). Stimulation of SVHK cells with 50 ng/mL of IFNγ for 24 h induced an approximately three-fold increase in STS activity and in its mRNA levels compared to non-treated cells. IFNγ treatment also induced an approximately 1.5-fold increase in STS mRNA levels in NHEK cells. This induction was completely inhibited by treatment with phosphatidylinositol (PI) 3-kinase inhibitors such as LY294002 or wortmannin, and by the nuclear factor-kappa B (NF-κB) inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ). These data suggest that activation of the PI 3-kinase signal transduction pathway mediates induction of STS gene expression by IFNγ through activation of NF-κB. The anti-inflammatory agent dexamethasone inhibited IFNγ induction of STS gene expression, suggesting involvement of a glucocorticoid receptor in the regulation of STS gene expression in keratinocytes. Regulation of STS gene expression in skin as a novel target of drugs for therapy of psoriasis in the skin is discussed.

Xanthurenic acid is an endogenous substrate for the silkworm cytosolic sulfotransferase, bmST1.

Sulfotransferase enzymes are known to regulate physiologically active substances such as steroids and catecholamines in mammals. Although invertebrates also express sulfotransferases, their biological function is mostly unclear. In a previous study, we reported that 4-nitrocatechol and the gallete ester are substrates for the silkworm sulfotransferase bmST1. The K(m) of bmST1 for these substrates is high. However, endogenous substrates of bmST1 have not yet been determined. We therefore investigated endogenous bmST1 substrates and carried out a detailed expression profile analysis of bmST1. We found that xanthurenic acid, a tryptophan metabolite, is a possible endogenous substrate of bmST1. The K(m) of bmST1 for xanthurenic acid is low, in the µM range, which is lower than that for previously reported substrates. Additionally, xanthurenic acid is a tryptophan metabolite that characteristically shows toxicity in vivo. High dose administration of xanthurenic acid resulted in inhibition of cuticular biosynthesis. The expression of the bmST1 gene reached a maximal level in the Malpighian tubule at the 4th molting stage, when amino acid metabolism might be activated. Our results suggest that bmST1 plays a role in detoxification of xanthurenic acid in the silkworm.

Sulfation of estradiol in human epidermal keratinocyte.

Epidermis is one of the well-known estrogen target tissues. Information regarding estrogen metabolism in epidermis is still very limited compared to that of estrogen action. In the breast cancer tissue, 17ß-estradiol (E(2)) is inactivated by sulfation and the expression level of estrogen sulfotransferase (SULT1E1) is inversely correlated with its malignancy. However, there is little datum about inactivation of estradiol in skin. In order to detect and measure E(2) and its metabolites simultaneously, we established an assay method with radio HPLC. A majority of [(3)H] labeled E(2) was converted to E(2) sulfate in normal human epidermal keratinocyte (NHEK) cells. The estimated activity of sulfotransferase toward E(2) at 20 nM was 0.11±0.01 (pmol/min/mg protein). Significant induction of estrogen sulfotransferase activity was observed in calcium-differentiated NHEK cells (0.58±0.07 (pmol/min/mg protein)). The gene expression of SULT1E1 was fifteen-fold higher in differentiated keratinocyte than in proliferating keratinocyte, whereas that of steroid sulfatase was reduced. These results suggest that E(2) inactivation is primarily mediated by SULT1E1 in keratinocyte and E(2) action is likely suppressed in epidermal differentiation.