Changes in alanine aminotransferase and body composition and metabolic factors among individuals receiving medical health checkups.

AIM: To examine the relationship between changes in alanine aminotransferase (ALT) and those in body composition and metabolic factors in participants receiving medical health checkups (4350 men [mean age 52.5 years] and 5398 women [mean age 50.5 years]) METHODS: We divided the participants into four types based on their ALT value at baseline and 1 year: A, ALT ≤30 (baseline) and ≤30 (1 year); B, ALT ≥31 (baseline) and ≤30 (1 year); C, ALT ≤30 (baseline) and ≥31 (1 year); and D, ALT ≥31 (baseline) and ≥31 (1 year). The change in each body composition-related parameter (waist circumference, fat mass, fat-free mass, fat mass to fat-free mass ratio, etc.) after 1-year was defined as Δ. RESULTS: The mean changes in waist circumference (cm) in the four types (A, B, C, and D) were -0.33, -1.54, 0.66, and -0.29 (overall p < 0.0001) in men, and -0.19, -0.90, 0.30, and 0.090 (overall p < 0.0001) in women. The mean changes in fat mass (kg) in the four types were -0.027, -0.86, 0.62, and 0.092 (overall p < 0.0001) in men, and 0.0067, -0.48, 0.39, and 0.063 (overall p < 0.0001) in women. The mean changes in fat-free mass (kg) in the four types were -0.028, -0.55, 0.42, and -0.034 (overall p < 0.0001) in men, and -0.0091, -0.34, 0.12, and -0.045 (overall p = 0.0012) in women. The mean changes in fat mass to fat-free mass ratio in the four types were -0.00042, -0.0120, 0.00837, and 0.00171 (overall p < 0.0001) in men, and -0.00013, -0.00817, 0.00730, and 0.00628 (overall p < 0.0001) in women. CONCLUSION: A decrease in ALT to ≤30 IU/L may be associated with improved body composition balance, but caution should be exercised for the decrease in muscle mass.

Body Composition in Patients With Metabolic Dysfunction-associated Steatotic Liver Disease: Impact of Body Surface Area.

BACKGROUND/AIM: To examine the relationship between the body surface area (BSA) and body composition in patients with metabolic dysfunction-associated steatotic liver disease (MASLD, 2,141 men and 986 women). MATERIALS AND METHODS: BSA and body composition parameters were examined. RESULTS: The median body mass index (BMI) was 25.0 kg/m2 for both men and women (p=0.7754). The median body surface area (BSA) was 1.854 m2 for men and 1.618 m2 for women (p<0.0001). In men, the median fat mass was 17.7 kg, whereas in women, it was 22.1 kg (p<0.0001). Additionally, the median fat-free mass was 55.4 kg in men and 39.3 kg in women (p<0.0001).). In male cases, BSA significantly correlated with fat mass (r=0.82, p<0.0001) and fat-free mass (r=0.95, p<0.0001). In female cases, BSA significantly correlated with fat mass (r=0.87, p<0.0001) and fat-free mass (r=0.94, p<0.0001). CONCLUSION: BSA could be a useful marker for the estimation of body composition in patients with MASLD.

Long-Term Outcomes after Switching to Tenofovir Alafenamide in Patients with Chronic Hepatitis B.

We sought to determine the long-term outcomes of chronic hepatitis B (CHB) cases switching to tenofovir alafenamide (TAF, n = 104, median age = 63.5 years). Data at switching to TAF (baseline) and those at 1, 2, 3, 4, and 5 years from switching to TAF were compared. At baseline, HB envelop antigen (HBeAg) seropositivity was found in 20 patients (19.2%), and undetectable HBV-DNA in 77 patients (74.0%). Percentage of detectable HBV-DNA significantly reduced at any time point. HB surface antigen (HBsAg) levels significantly reduced at 3, 4, and 5 years. The percentage of HBeAg seropositivity significantly reduced at 5 years. HB core related antigen levels did not significantly change. In patients with baseline HbeAg seropositivity, HbsAg levels significantly reduced at any time point, and a similar trend was found in patients without HBeAg seropositivity. In patients with baseline FIB4 index >1.85, HBsAg levels significantly reduced at 3, 4, and 5 years, and in patients with baseline FIB4 index <1.85, HBsAg levels significantly reduced at any time point. The estimated glomerular filtration rate significantly reduced only at 5 years. The discontinuation rate owing to the side effects of TAF was 0%. In conclusion, switching to TAF therapy in patients with CHB may be effective and safe at least up to 5 years.

Insulin Resistance: A Marker for Fat-to-Lean Body Composition in Japanese Adults.

We sought to investigate the relationship between insulin resistance (IR) and body composition as assessed by bioelectrical impedance analysis in Japanese health check-up recipients (1186 men and 1441 women). IR was defined as a Homeostasis Model Assessment of IR (HOMA-IR) ≥ 2.5. In body-composition-related parameters, the fat mass index (F index) was defined as fat mass divided by the height squared (kg/m2). The fat-free mass index (FF index) was defined as fat-free mass divided by the height squared (kg/m2). The F index to FF index ratio (F-FF ratio) was defined as the F index divided by the FF index. Factors related to HOMA-IR were examined. The median HOMA-IR was 1.54 in men and 1.30 in women (p < 0.0001). The median F index was 4.9 kg/m2 in men and 6.1 kg/m2 in women (p < 0.0001). The median FF index was 18.2 kg/m2 in men and 15.1 kg/m2 in women (p < 0.0001). The median F-FF ratio was 0.272 in men and 0.405 in women (p < 0.0001). The F-FF ratio was an independent factor associated with HOMA-IR in the multivariate analysis in both genders, while the F index and FF index were not in both genders. In conclusion, fat and skeletal muscle balance can be controlled by IR in Japanese adults.

Association between the Suita Score and Body Composition in Japanese Adults: A Large Cross-Sectional Study.

The purpose of this study was to clarify the relationship between the Suita score (a prediction model for the development of cardiovascular disease) and body composition in Japanese health check-up subjects (6873 men and 8685 women). The Suita score includes 8 items (age, gender, smoking, diabetes, blood pressure, low-density lipoprotein, high-density lipoprotein, and chronic kidney disease). Factors associated with the Suita score within body composition-related parameters (body mass index (BMI), waist circumference (WC), fat mass index, fat-free mass index, fat mass to fat-free mass ratio (F-FF ratio), and water mass index) as assessed by bioelectrical impedance analysis were examined. The mean age of subjects was 54.8 years in men and 52.8 years in women (p < 0.0001). The mean BMI was 23.9 kg/m2 in men and 21.8 kg/m2 in women (p < 0.0001). Diabetes mellitus was found in 1282 subjects (18.7%) among men and 816 subjects (9.4%) among women (p < 0.0001). The mean Suita score was 42.0 in men and 29.6 in women (p < 0.0001). In multivariate analysis, WC (p < 0.0001), F-FF ratio (p < 0.0001), and water mass index (p < 0.0001) were independent factors linked to the Suita score for both genders. In conclusion, body composition can be associated with the Suita score in Japanese adults receiving health check-ups.

Body Composition Analysis in Patients with Metabolic Dysfunction-Associated Fatty Liver Disease.

We sought to examine body composition using bioimpedance analysis in patients with metabolic dysfunction-associated fatty liver disease (MAFLD, 2014 males and 949 females). Factors linked to the fat-free mass index (FF index) were examined using univariate and multivariate analysis. An FF index < 18 kg/m2 in males and an FF index < 15 kg/m2 in females were defined as having decreased skeletal muscle mass. The median age and body mass index (BMI) were 55 years and 25.4 kg/m2 in males, and 57 years and 25.4 kg/m2 in females, respectively. The FF index strongly correlated with muscle mass index both in males (r = 0.999) and females (r = 0.999). The prevalence of patients with an FF index < 18 kg/m2 in males and an FF index < 15 kg/m2 in females was well stratified according to age, BMI, severity of FL, and FIB4 index. In the males, in the multivariate analysis, BMI (p < 0.0001), fat mass index (p < 0.0001), and waist circumference (p = 0.0050) were found to be significant factors linked to FF index. In the females, in the multivariate analysis, BMI (p < 0.0001) and fat mass index (p < 0.0001) were found to be significant. In conclusion, fat accumulation as reflected by BMI, which is an easily available marker, could be a useful indicator for the skeletal muscle mass in MAFLD.

Accurate SARC-F Score in Patients with Liver Disease.

SARC-F is a well-accepted screening tool for sarcopenia. A SARC-F value of 1 point is reported to be more discriminating in identifying sarcopenia than 4 points (recommended cutoff point). The prognostic impact of the SARC-F score was investigated in patients with liver disease (LD, n = 269, median age = 71 years, 96 hepatocellular carcinoma (HCC) cases). Factors associated with SARC-F ≥ 4 points and SARC-F ≥ 1 point were also examined. In the multivariate analysis, age (p = 0.048), and Geriatric Nutritional Risk Index (GNRI) score (p = 0.0365) were significant factors linked to SARC-F ≥ 1 point. In our patients with LD, the SARC-F score is well correlated with the GNRI score. The 1-year cumulative overall survival ratio in patients with SARC-F ≥ 1 (n = 159) and SARC-F 0 (n = 110) was 78.3% and 90.1% (p = 0.0181). After excluding 96 HCC cases, similar tendencies were found (p = 0.0289). In the receiver operating curve (ROC) analysis based on the prognosis for the SARC-F score, the area under the ROC was 0.60. The sensitivity was 0.57, the specificity was 0.62, and the optimal cutoff point of the SARC-F score was 1. In conclusion, sarcopenia in LDs can be affected by nutritional conditions. A SARC-F score of ≥1 is more useful than a score of 4 in predicting the prognosis of patients with LD.

Prognostic Nutritional Index Correlates with Liver Function and Prognosis in Chronic Liver Disease Patients.

The Prognostic Nutritional Index (PNI) is widely recognized as a screening tool for nutrition. We retrospectively examined the impact of PNI in patients with chronic liver disease (CLD, n = 319, median age = 71 years, 153 hepatocellular carcinoma (HCC) patients) as an observational study. Factors associated with PNI < 40 were also examined. The PNI correlated well with the albumin-bilirubin (ALBI) score and ALBI grade. The 1-year cumulative overall survival rates in patients with PNI ≥ 40 (n = 225) and PNI < 40 (n = 94) were 93.2% and 65.5%, respectively (p < 0.0001). In patients with (p < 0.0001) and without (p < 0.0001) HCC, similar tendencies were found. In the multivariate analysis, hemoglobin (p = 0.00178), the presence of HCC (p = 0.0426), and ALBI score (p < 0.0001) were independent factors linked to PNI < 40. Receiver operating characteristic (ROC) curve analysis based on survival for the PNI yielded an area under the ROC curve of 0.79, with sensitivity of 0.80, specificity of 0.70, and an optimal cutoff point of 42.35. In conclusion, PNI can be a predictor of nutritional status in CLD patients. A PNI of <40 can be useful in predicting the prognosis of patients with CLD.

Effect of Seat Angle when Sleeping in a Car on Quality of Sleep and Its Impact on Calculation Performance the Following Day.

The number of occasions to stay in a car overnight is increasing during disasters; however, the effects on sleep and the impact on daytime functioning are not well understood. We investigated the effect of seat angle when sleeping in a car and its impact on calculation performance the following day. Fifteen healthy males participated in three trials (sleeping in a car with the front seat angled at 45° and 60° in a laboratory and sleeping at home); sleep and calculation performance the following day were compared. Increased wake after sleep onset and decreased slow-wave sleep were observed in the 60° trial, that is, near-vertical, compared with the others. Subjective sleep quality and calculation performance in the 45° and 60° trials were poorer than those in the home trial. The effect of seat angle on sleep was confirmed objectively, but not subjectively, suggesting that a large seat angle might cause sleep impairment.

Effect of an Electronic Alert System on Hepatitis B Virus Reactivation in Patients Receiving Immunosuppressive Drug Therapy.

Hepatitis B virus (HBV) reactivation (HBVr) can occur in patients receiving immunosuppressive drug therapies, causing significant morbidity and mortality. Although the guidelines for HBVr have been proposed by several academic societies, some providers do not follow them, resulting in HBVr and death. As HBV-DNA levels increase before liver enzyme levels do, we previously constructed an electronic alert system that recommends the measurement of HBV-DNA. Here, we investigated whether this alert system improves the HBV-DNA measurement rate and elicits responses according to guidelines. A total of 5329 patients were divided into two groups, before and after the introduction of the alert system, and the HBV-DNA measurement rates in both groups were compared. Because of the introduction of the alert system, the HBV-DNA measurement rate among HBsAg-negative patients with anti-HBs and/or anti-HBc before immunosuppressive drug therapy improved significantly. The HBV-DNA monitoring rate within 3 months also improved significantly (p = 0.0034) in HBV-remission phase patients. HBVr was detected immediately, and the affected patients were treated with nucleotide analogs before severe hepatitis onset. The introduction of the alert system for HBVr improved the HBV-DNA measurement rates in patients receiving immunosuppressive drug therapy, leading to the rapid treatment of patients with HBVr.

Comparison of post-implant dosimetrics between intraoperatively built custom-linked seeds and loose seeds by sector analysis at 24 hours and 1 month for localized prostate cancer.

PURPOSE: To compare post-implant dosimetrics between intraoperatively built custom-linked (IBCL) seeds and loose seeds (LS) at 24 hours and 1 month by sector analysis, and to evaluate the effect of IBCL seeds with regard to change in dosimetric parameters, in patients with prostate cancer treated with brachytherapy. MATERIAL AND METHODS: Consecutive patients treated for localized prostate cancer who received definitive brachytherapy between March 2013 and October 2017 were retrospectively analyzed. Prostate V100 (PV100), prostate D90 (PD90), prostate V150 (PV150), urethral D30 (UD30), urethral V150 (UV150), and rectal V100 (RV100) were assessed. RESULTS: Thirty-two patients were treated with LS and 32 patients were treated with IBCL seeds. The median follow-up time was 49.9 months in the LS group and 27.1 months in the IBCL group. PV150, UV150, and UD30 at 24 hours and UD30 at 1 month showed significant difference (F-test), and standard deviation (SD) tended to be lower in the IBCL group. Analysis of change in the variables revealed significance for ΔPV100 and ΔPD90 (F-test, p = 0.014 and < 0.001, respectively), and ΔPV150 and ΔUD30 showed marginal significance (p = 0.084 and 0.097, respectively). PV150, UV150, and UD30 at 24 hours and 1 month were significantly lower in the IBCL group, and there was no significant difference in PV100, PD90, and RV100 compared with the LS group (t-test). The homogeneity index (HI) was significantly higher in the IBCL group (p < 0.001). CONCLUSIONS: In this retrospective single institutional study, there was a decrease in the SD of the dosimetric parameters in the IBCL group, and it was statistically significant in change in the variables between 24 hours and 1 month (F-test). The use of IBCL seeds significantly decreased PV150, UV150, and UD30, and significantly improved HI, without lowering PD90 or PD100.

Liver dysfunction is associated with poor prognosis in patients after immune checkpoint inhibitor therapy.

Immune-related adverse events (irAEs) are induced by immune checkpoint inhibitors (ICIs). Liver is one of the main target organs which irAEs occur and we investigated the influence of liver dysfunction on prognosis of patients after ICIs. From July 2014 to December 2018, 188 patients with diverse cancers who received ICIs (nivolumab or pembrolizumab) were enrolled. Twenty-nine patients experienced liver dysfunction of any grades after ICIs. Progression-free survival (PFS) was significantly shorter in the liver dysfunction-positive group than in the liver dysfunction-negative group, and a similar result was obtained for Overall survival (OS). Multiple logistic regression analysis revealed liver metastasis and alanine aminotransferase before ICIs were associated with a higher incidence of liver dysfunction after ICIs. Regardless of liver metastasis, PFS and OS were significantly shorter in the liver dysfunction-positive group. In conclusion, this study suggests liver dysfunction is associated with poor prognosis in patients after ICIs with diverse cancers.

The preventive effect of the impaired liver function for antiemetic therapy against chemotherapy-induced nausea and vomiting in hepatocellular carcinoma patients.

Transarterial chemoembolization and hepatic arterial infusion chemotherapy are recommended for the treatment in patients with intermediate stage of hepatocellular carcinoma. Impaired liver function was sometime observed in patients with hepatocellular carcinoma after transarterial chemoembolization or hepatic arterial infusion chemotherapy. However, what kinds of factors deeply influence in impaired liver function are not clear. A retrospective study was performed to evaluate the risk factors of impaired liver function in cisplatin-naïve patients treated with these therapies using cisplatin. Prior to and 2 months after these therapies, we analyzed the liver function by Child-Pugh score in these patients. For assessing the severity of chemotherapy-induced nausea and vomiting, we utilized the Common Terminology Criteria for Adverse Events ver. 4.0. In hepatocellular carcinoma patients received these therapies using cisplatin, the cancer stage and treatment without neurokinin-1 (NK1) antagonist were found to be independent risk factors of the impaired liver function. The treatment with NK1 antagonist was effective in reducing chemotherapy-induced nausea and vomiting and patients treated with NK1 antagonist kept their liver functions after cisplatin-used these therapies. The treatment with NK1 antagonist was effective in chemotherapy-induced nausea and vomiting and prevented the impaired liver function associated with cisplatin-used these therapies in hepatocellular carcinoma patients.

Photocatalyzed Site-Selective C(sp3)-H Functionalization of Alkylpyridines at Non-Benzylic Positions.

Tetrabutylammonium decatungstate (TBADT)-photocatalyzed C-H functionalization of alkylpyridines was investigated. Unlike alkylbenzene counterparts, alkylation of α-C-H bonds did not proceed for the reaction of 2- and 4-alkylpyridines and reluctantly proceeded for 3-alkylpyridines, which allow site-selective C(sp3)-H functionalization at nonbenzylic positions. The observed nonbenzylic site selectivities are rationalized by the polar inductive effects of pyridyl groups in the SH2 transition states. Consecutive γ-functionalization and α-bromofunctionalization were successfully carried out in selected cases.

Correlations of post-implant regional dosimetric parameters at 24 hours and one month, with clinical results of low-dose-rate brachytherapy for localized prostate cancer.

PURPOSE: To evaluate the correlations of post-implant regional dosimetrics at 24 hours (24 h) and 1 month after implant procedures, with clinical outcomes of low-dose-rate (LDR) brachytherapy for localized prostate cancer. MATERIAL AND METHODS: Between January 2008 and December 2014, 130 consecutive patients treated for localized prostate cancer, receiving definitive iodine-125 (125I) brachytherapy treatment were retrospectively analyzed. All patients underwent post-implant CT imaging for dosimetric analysis at 24 h and 1 month after implantation procedure. Prostate contours were divided into quadrants: anterior-superior (ASQ), posterior-superior (PSQ), anterior-inferior (AIQ), and posterior-inferior (PIQ). Predictive factors and cut-off values of biochemical failure-free survival (BFFS) and toxicities of LDR brachytherapy were analyzed. RESULTS: The median follow-up time was 69.5 months. Seven patients (5.4%) had biochemical failure. The 3-year and 5-year BFFS rates were 96.7% and 93.1%, respectively. On multivariate analysis, prostate-specific antigen and Gleason score were significant prognostic factors for biochemical failure. D90 (the minimal dose received by 90% of the volume) of PSQ and PIQ at 24 h, and D90 of PSQ at 1 month were also significant factors. The cut-off values of PSQ D90 were 145 Gy at 24 h and 160 Gy at 1 month. D90 of the whole prostate was not significant at 24 h and at 1 month. D90 of PSQ at 1 month was a significant factor for rectal hemorrhage. CONCLUSIONS: Post-implant D90 of PSQ is significantly associated with BFFS for localized prostate cancer not only at 1 month, but also at 24 hours. D90 of PSQ at 1 month is also a significant factor for rectal hemorrhage.

Measurement of beam profiles by terahertz sensor card with cholesteric liquid crystals.

We demonstrate a sensor card with cholesteric liquid crystals (CLCs) for terahertz (THz) waves generated from a nonlinear crystal pumped by a table-top laser. A beam profile of the THz waves is successfully visualized as color change by the sensor card without additional electronic devices, power supplies, and connecting cables. Above the power density of 4.3 mW/cm2, the approximate beam diameter of the THz waves is measured using the hue image that is digitalized from the picture of the sensor card. The sensor card is low in cost, portable, and suitable for various situations such as THz imaging and alignment of THz systems.

Time course of expression of the retinoid X receptor gene and induction of imposex in the rock shell, Thais clavigera, exposed to triphenyltin chloride.

To examine the role of the retinoid X receptor (RXR) in the development of imposex in gastropods, we investigated the time course of expression of the RXR gene in various tissues (ctenidium, ovary or testis, digestive gland, penis-forming area or penis, and head ganglia) of female and male rock shells (Thais clavigera) exposed to triphenyltin (TPT) in a flow-through exposure system for 3 months. Accumulations of TPT in tissues were clearly observed in exposed individuals, whereas no accumulation of TPT was observed in the control groups. In females, 3-month exposure to TPT resulted in the development of imposex, and penis lengths in imposex-exhibiting females were significantly longer in small females (shell height <20 mm) than in large females (shell height > or = 20 mm). RXR gene expression in the ovary, penis-forming area or penis, and head ganglia of females exposed for 3 months was significantly higher than expression in control females, and the highest RXR gene expression was found in the penis-forming area or penis. Moreover, RXR gene expression in the penis-forming area or penis of each female exposed to TPT seemed to be associated with an increase in penis length. In males, the ratio of penis length to shell height was significantly larger in the exposed groups than in the controls. Although RXR gene expression in males exposed for 3 months was not significantly higher than expression in control males in any tissues, the highest gene expression was observed in the penis of exposed males. These results suggest that RXR plays an important role in the development of male genitalia (i.e., penis and vas deferens) in gastropods, although RXR might also have other physiological functions.

Interfacial electron-transfer kinetics in metal-free organic dye-sensitized solar cells: combined effects of molecular structure of dyes and electrolytes.

Electron diffusion coefficient, lifetime, and density in the TiO(2) electrode of dye-sensitized TiO(2) solar cells (DSCs) employing I(-)/I(3)(-) redox couples were measured with eight different metal-free organic dyes and three Ru complex dyes. At matched electron density, all DSCs using organic dyes (ODSCs) showed shorter electron lifetime with comparable or larger diffusion coefficients in comparison to the DSCs using the Ru dyes (RuDSC). The shorter lifetime was attributed partially to the slower dye cation reduction rate of the organic dyes by I(-), faster electron diffusion coefficient in the TiO(2), and mostly higher I(3)(-) concentration in the vicinity of the TiO(2) surface. Whereas a slight shift of the conduction band edge potential (E(cb)) of the TiO(2) was seen with a few organic dyes, no correlation was found with the dipole moment of the adsorbed dyes. This implies that the adsorbed dyes interact with cations in the electrolyte, so the direction of the dipole is altered or simply screened. The increase of [I(3)(-)] in the vicinity of the TiO(2) surface was interpreted with partial charge distribution of the dyes. Under one-sun conditions, less electron density due to shorter electron lifetime was found to be the main reason for the lower values of V(oc) for all ODSCs in comparison to that of RuDSCs. Among the organic dyes, having larger molecular size and alkyl chains showed longer electron lifetime, and thus higher V(oc). Toward higher open circuit voltage, a design guide of organic dyes controlling the electron lifetime is discussed.

Exposure to 9-cis retinoic acid induces penis and vas deferens development in the female rock shell, Thais clavigera.

To clarify how tributyltin (TBT) and triphenyltin (TPT) interact with the retinoid X receptor (RXR) to induce growth of male sex organs in female gastropods, we treated female rock shells (Thais clavigera) with three different concentrations (0.1, 1, or 5 microg/g wet wt) of 9-cis-retinoic acid (9CRA) or with a single concentration (1 microg/g wet wt) of TBT, TPT, or fetal bovine serum (as a control). The effects of each treatment were measured as the incidence of imposex, the length of the penis-like structure, and the vas deferens sequence (VDS) index. 9CRA induced imposex in a dose-dependent manner; imposex incidence was significantly higher in the rock shells that received 1 (P < 0.05) or 5 microg (P < 0.001) 9CRA than in the controls. After 1 month, the rock shells treated with 5 microg 9CRA exhibited substantial growth of the penis-like structure that was not as evident in the other treated shells. The length of the structure differed between the 0.1- and 5-microg 9CRA treatment groups (P < 0.05) but not between the 1- and 5-microg 9CRA treatment groups (P > 0.05). Compared with the control, the VDS index increased significantly in the 1- (P < 0.05) and 5-microg (P < 0.001) 9CRA groups. The penis-like structures behind the right tentacle in female rock shells treated with 5 microg 9CRA were essentially the same as the penises and vasa deferentia of normal males and of TBT-treated or TPT-treated imposexed females. These results further support the hypothesis that imposex in gastropods could be mediated by RXR.

Retinoid X receptor gene expression and protein content in tissues of the rock shell Thais clavigera.

To elucidate the role of retinoid X receptor (RXR) in the development of imposex caused by organotin compounds in gastropod molluscs, we investigated RXR gene expression and RXR protein content in various tissues of male and female wild rock shells (Thais clavigera). Quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemistry with a commercial antibody against human RXR alpha revealed that RXR gene expression was significantly higher in the penises of males and imposex-exhibiting females than in the penis-forming areas of normal females (P<0.01 and P<0.05, respectively). Western blotting demonstrated that the antibody could detect rock shell RXR and showed that the male penis had the highest content of RXR protein among the analyzed tissues of males and normal females. Immunohistochemical staining revealed nuclear localization of RXR protein in the epithelial and smooth muscle cells of the vas deferens and in the interstitial or connective tissues and epidermis of the penis in males and imposex-exhibiting females. RXR could be involved in the mechanism of induction of male-type genitalia (penis and vas deferens) by organotin compounds in female rock shells.