The safety and efficacy outcomes of Minnelide given alone or in combination with paclitaxel in advanced gastric cancer: A phase I trial.

Minnelide is a water-soluble disodium salt variant of triptolide, an HSP70 inhibitor that can prevent tumor progression and induce apoptosis. Maximum tolerated dose (MTD), safety, and antitumor activity of Minnelide alone and its combination with paclitaxel were evaluated in this open-label, single-center, dose-escalation phase I study (NCT05566834) in patients who were previously treated for advanced gastric cancer (AGC). Minnelide was administered orally using a 3 + 3 dose-escalation design as monotherapy (Regimen A), and in combination with paclitaxel (Regimen B & C). Our results show that no patients experienced dose limiting toxicity (DLT) in the combination group (Regimen B& C) while 2 patients experienced DLT from the Regimen A group (n = 11) (Minnelide 1.5 mg). The MTD was Minnelide 1.25 mg once daily for 21days Q4 weeks as monotherapy. The most common Grade ≥3 AEs were neutropenia (19.4 %) and abdominal pain (11.1 %). In Regimen C, 71.5 % achieved either a partial response or a stable disease with the median PFS of 4.5 months, and the median OS of 10.7 months. The combination of Minnelide plus paclitaxel as salvage treatment in AGC patients showed meaningful clinical activity with a manageable safety profile. Based on these encouraging results, a phase II study is being initiated to test the effectiveness of the combination regimen in patients with advanced gastric cancer.

Cross-sectional and Longitudinal Associations Between Propylene Oxide Exposure and Lung Function Among Chinese Community Residents: Roles of Oxidative DNA Damage, Lipid Peroxidation, and Protein Carbonylation.

BACKGROUND: Toxicologic studies have reported propylene oxide (PO) exposure may harm the respiratory system, but the association between PO exposure and lung function and potential mechanism remains unclear. RESEARCH QUESTION: What is the association between PO exposure and lung function and potential mediating mechanism? STUDY DESIGN AND METHODS: Urinary PO metabolite [N-Acetyl-S-(2-hydroxypropyl)-L-cysteine (2HPMA)] as PO internal exposure biomarker and lung function were measured for 3,692 community residents at baseline and repeated at 3-year follow up. Cross-sectional and longitudinal associations between urinary 2HPMA and lung function were assessed by linear mixed model. Urinary 8-hydroxy-deoxyguanosine, urinary 8-iso-prostaglandin-F2α, and plasma protein carbonyls as biomarkers of oxidative DNA damage, lipid peroxidation, and protein carbonylation, respectively, were measured for all participants to explore their potential roles in 2HPMA-associated lung function decline by mediation analysis. RESULTS: After adjustment for potential covariates, each threefold increase in urinary 2HPMA was cross sectionally associated with a 26.18 mL (95% CI, -50.55 to -1.81) and a 21.83 mL (95% CI, -42.71 to -0.95) decrease in FVC and FEV1, respectively, at baseline (all P < .05). After 3 years of follow up, 2HPMA was observed to be longitudinally associated with FEV1/FVC decline. No significant interaction effect of smoking or passive smoking was observed (Pinteraction > .05), and the associations between 2HPMA and lung function indexes were persistent among participants who were not smoking and those who were not passive smoking in both baseline and follow-up evaluations. We observed urinary 8-hydroxy-deoxyguanosine partially mediated the associations of 2HPMA with FVC (mediation proportion, 5.48%) and FEV1 (mediation proportion, 6.81%), and plasma protein carbonyl partially mediated the association between 2HPMA and FEV1 (mediation proportion, 3.44%). INTERPRETATION: PO exposure was associated with lung function decline among community residents, and oxidative DNA damage and protein carbonylation partially mediated PO exposure-associated lung function decline. Further attention on respiratory damage caused by PO exposure is warranted.

Triptolide Induces Liver Injury by Regulating Macrophage Recruitment and Polarization via the Nrf2 Signaling Pathway.

Triptolide (TP) has limited usage in clinical practice due to its side effects and toxicity, especially liver injury. Hepatic macrophages, key player of liver innate immunity, were found to be recruited and activated by TP in our previous study. The nuclear factor-erythroid-2-related factor 2 (Nrf2) pathway exerts a protective role in TP-induced liver damage, but its effect on the functions of hepatic macrophage has not been elucidated. Here, we determined whether TP can regulate the recruitment and polarization of hepatic macrophages by inhibiting Nrf2 signaling cascade. Our results demonstrated that TP inhibited the Nrf2 signaling pathway in hepatic macrophages. The changes in hepatic macrophages were responsible for the increased susceptibility toward inflammatory stimuli, and hence, TP pretreatment could induce severe liver damage upon the stimulation of a nontoxic dose of lipopolysaccharides. In addition, the Nrf2 agonist protected macrophages from TP-induced toxicity and Nrf2 deficiency significantly aggravated liver injury by enhancing the recruitment and M1 polarization of hepatic macrophages. This study suggests that Nrf2 pathway-mediated hepatic macrophage polarization plays an essential role in TP-induced liver damage, which can serve as a potential therapeutic target for preventing hepatotoxicity induced by TP.

Characterization of patients with occupational allergy to two new epoxy hardener compounds.

BACKGROUND: The practical importance of two recently described epoxy hardener allergens-1,3-benzenedimethanamine, N-(2-phenylethyl) derivatives (1,3-BDMA-D) and hydrogenated formaldehyde benzenamine polymer (FBAP)-as occupational allergens remains to be defined. OBJECTIVES: To describe patients diagnosed at the Finnish Institute of Occupational Health (FIOH) with positive reactions to 1,3-BDMA-D or FBAP. METHODS: We searched FIOH's patch-test files from January 2017 to December 2020 for patients examined due to suspected occupational contact allergy to epoxy compounds. We analyzed the patch-test results and sources of exposure to various epoxy hardeners and focused on occupations, symptoms, and the sources of exposure to 1,3-BDMA-D and FBAP. RESULTS: During the study period, 102 patients were examined at FIOH for suspected occupational contact allergy to epoxy compounds. Of these, 19 (19%) were diagnosed with contact allergy to 1,3-BDMA-D (n = 10) or FBAP (n = 12). The largest occupational group was sewage pipe reliners (n = 8). Seven different hardener products contained FBAP, whereas 1,3-BDMA-D was present in only one hardener used by spray painters. CONCLUSIONS: A substantial number of patients with suspected occupational epoxy resin system allergy tested positive to in-house test substances of 1,3-BDMA-D and/or FBAP.

Effect of triptolide and chemotherapy on carcinoembryonic and carbohydrate antigens levels and first-line treatment of recurrent nasopharyngeal carcinoma.

To investigate the first-line treatment of recurrent Nasopharyngeal Carcinoma treprimcab combined with chemotherapy. From January 2019 to January 2020, 48 patients with recurrent nasopharyngeal Carcinoma (RNPC) were treated in our hospital. According to the method of the random number, 24 patients were divided into the combined group and the Control Group. The patients in the combined group were given the Combined Treatment of triptolide and chemotherapy. While the Control Group only received chemotherapy. The therapeutic effects and adverse reactions of the two groups were compared, the levels of Carcinoembryonic Antigen (CEA) and carbohydrate Antigen 19-9 (CA19-9) were measured before and after treatment. The total effective rate of the combined group was 79.17% higher than that of the control group (62.50%). The total effective rate of the two groups was statistically significant (P & Lt; 0.05). The incidence of grade i/ii adverse reaction in the control group was lower than that in the combined group, such as nausea and vomiting, oral mucositis, Leukopenia, liver and kidney function damage, central granulocyte count reduction, anaemia adverse reaction. The incidence of grade iii/iv Adr in the control group was higher than that in the combined group. The incidence of grade i/ii Adr in the thrombocytopenia group was higher than that in the combined group, and the incidence of grade iii/iv Adr in the control group was lower than that in the combined group. The side effects of nausea and vomiting and oral mucositis in the control group and the combined group were statistically significant (P & Lt; 0.05). There was no significant difference between the control group and the combined group in the incidence of Leukopenia, liver and kidney injury, neutrophil, anaemia and Thrombocytopenia (P & GT; 0.05). The level of CD4 + / CD8 + in control group and combined group before treatment was higher than that after treatment (P & Lt; 0.05). The quality of life of the combined group was 91.67% higher than that of the control group (70.83%). The quality of life of the control group was significantly higher than that of the combined group (P & Lt; 0.05). The levels of CEA and CA19-9 in the two groups after treatment were lower than those before treatment, and the levels of CEA and CA19-9 in the combined group were lower than those in the control group (P & Lt; 0.05). The first-line treatment of recurrent nasopharyngeal Carcinoma with triprimmab combined with chemotherapy has a good clinical effect and has a broad clinical research prospect.

Black raspberry restores the expression of the tumor suppressor p120ctn in the oral cavity of mice treated with the carcinogen dibenzo[a,l]pyrene diol epoxide.

One of the major risk factors for head and neck squamous cell carcinoma (HNSCC) is tobacco smoke exposure, but the mechanisms that can account for disease development remain to be fully defined. Utilizing our HNSCC mouse model, we analyzed oral squamous cell carcinomas (OSCC) induced by the active metabolite of a common smoke constituent, dibenzo[a,l]pyrene diol-epoxide (DBPDE). Analyzing protein expression by either immunofluorescence or immunohistochemistry, we identified biologic processes that are dysregulated in premalignant and invasive cancer lesions induced by DBPDE. Interestingly, p120ctn expression is downregulated in both stages of the disease. In addition to decreased p120ctn expression, there was also increased proliferation (as measured by Ki67), inflammation (as measured by NFkB (p65) expression), neovascularization (as measured by CD31) and recruitment of Ly6G-positive immune cells as well as strong EGFR expression. We also examined the effect of the chemopreventive agent black raspberry (BRB) on p120ctn and EGFR protein expression in DBPDE treated mice. p120ctn, but not EGFR, protein expression increased in mice treated with BRB. Our results suggest that modulation of p120ctn may, in part, account for the mechanism by which BRB inhibits DBPDE induced OSCC in mice.

Targeted therapy of rheumatoid arthritis via macrophage repolarization.

The polarization of macrophages plays a critical role in the physiological and pathological progression of rheumatoid arthritis (RA). Activated M1 macrophages overexpress folate receptors in arthritic joints. Hence, we developed folic acid (FA)-modified liposomes (FA-Lips) to encapsulate triptolide (TP) (FA-Lips/TP) for the targeted therapy of RA. FA-Lips exhibited significantly higher internalization efficiency in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells than liposomes (Lips) in the absence of folate. Next, an adjuvant-induced arthritis (AIA) rat model was established to explore the biodistribution profiles of FA-Lips which showed markedly selective accumulation in inflammatory paws. Moreover, FA-Lips/TP exhibited greatly improved therapeutic efficacy and low toxicity in AIA rats by targeting M1 macrophages and repolarizing macrophages from M1 to M2 subtypes. Overall, a safe FA-modified liposomal delivery system encapsulating TP was shown to achieve inflammation-targeted therapy against RA via macrophage repolarization.

Altered integrity of hepatocyte tight junctions in rats with triptolide-induced cholestasis.

Triptolide (TP), an active component of Tripterygium wilfordiiHook. f. (TWHF), has been widely used for centuries as a traditional Chinese medicine. However, the clinical application of TP has been restricted due to multitarget toxicity, such as hepatotoxicity. In this study, 28 days of oral TP administration (100, 200, or 400 µg·kg-1·d-1) induced the occurrence of cholestasis in female Wistar rats, as evidenced by increased serum levels of γ-glutamyl transpeptidase (γ-GGT), alkaline phosphatase (ALP) and hepatic total bile acids (TBAs). In addition, the heptocyte polarity associated with the strcture of tight junctions (TJs) was disrupted in both rats and sandwich-cultured primary hepatocytes. Immunoblotting revealed decreased expression of the TJ-associated proteins occludin, claudin-1, and zonula occludens protein (ZO-1), and downregulated mRNA levels of these TJs was also detected by real-time PCR. An immunofluorescence analysis showed abnormal subcellular localization of occludin, claudin-1 and ZO-1, which was also confirmed by transmission electron microscopy. Moreover, the concentration of FITC-dextran, a marker of paracellular penetration, was found to increase rapidly in bile increased rapidly (within 6 minutes) after treatment with TP, which indicated the functional impairment of TJs. Taken together, these results suggest that the administration of TP for 28 consecutive days to rats could induce cholestatic injury in the liver, and the increased paracellular permeability might play an important role in these pathological changes.

Ethnic differences in excretion of butadiene-DNA adducts by current smokers.

1,3-Butadiene (BD) is a known human carcinogen used in the synthetic polymer industry and also found in cigarette smoke, automobile exhaust and wood burning smoke. BD is metabolically activated by cytochrome P450 monooxygenases (CYP) 2E1 and 2A6 to 3,4-epoxy-1-butene (EB), which can be detoxified by GST-catalyzed glutathione conjugation or hydrolysis. We have previously observed ethnic differences in urinary levels of EB-mercapturic acids in white, Japanese American and Native Hawaiian smokers. In the present study, similar analyses were extended to urinary BD-DNA adducts. BD-induced N7-(1-hydroxy-3-buten-2-yl) guanine (EB-GII) adducts were quantified in urine samples obtained from smokers and non-smokers belonging to three racial/ethnic groups: white, Japanese American and Native Hawaiian. After adjusting for sex, age, nicotine equivalents, body mass index and batch, we found that Japanese American smokers excreted significantly higher amounts of urinary EB-GII than whites [1.45 (95% confidence interval: 1.12-1.87) versus 0.68 (95% confidence interval: 0.52-0.85) fmol/ml urine, P = 4 × 10-5]. Levels of urinary EB-GII in Native Hawaiian smokers were not different from those in whites [0.67 (95% confidence interval: 0.51-0.84) fmol/ml urine, P = 0.938]. There were no racial/ethnic differences in urinary EB-GII adduct levels in non-smokers. Racial/ethnic differences in urinary EB-GII adduct levels in smokers could not be explained by GSTT1 gene deletion or CYP2A6 enzymatic activity. Urinary EB-GII adduct levels in smokers were significantly associated with concentrations of BD metabolite dihyroxybutyl mercapturic acid. Overall, our results reveal that urinary EB-GII adducts in smokers differ across racial/ethnic groups. Future studies are required to understand genetic and epigenetic factors that may be responsible for these differences.

Arctiin Antagonizes Triptolide-Induced Hepatotoxicity via Activation of Nrf2 Pathway.

Triptolide (TP) is the most effective ingredient found in the traditional Chinese herbal Tripterygium wilfordii Hook F, and it is widely used in therapies of autoimmune and inflammatory disorders. However, the hepatotoxicity induced by TP has restricted its use in clinical trials. Arctiin is known as a protective agent against oxidative stress, and it exerts liver-protecting effect. This study was aimed at investigating the protective role of arctiin against TP-induced hepatotoxicity using in vitro and in vivo models. The results indicated that TP not only obviously induced liver injury in mice but also significantly inhibited the growth of HepG2 cells and increased the level of intracellular reactive oxygen. Furthermore, TP obviously decreased the expressions of proteins of Nrf2 pathway including HO-1, NQO1, and Nrf2 associated with oxidative stress pathway. However, the above experimental indexes were reversed by the treatment of arctiin. Our results suggested that arctiin could alleviate TP-induced hepatotoxicity, and the molecular mechanism is likely related to its capacity against oxidative stress.

Effect of CYP3A4 on liver injury induced by triptolide.

Triptolide (TP), one of the main bioactive diterpenes of the herbal medicine Tripterygium wilfordii Hook F, is used for the treatment of autoimmune diseases in the clinic and is accompanied by severe hepatotoxicity. CYP3A4 has been reported to be responsible for TP metabolism, but the mechanism remains unclear. The present study applied a UPLC-QTOF-MS-based metabolomics analysis to characterize the effect of CYP3A4 on TP-induced hepatotoxicity. The metabolites carnitines, lysophosphatidylcholines (LPCs) and a serious of amino acids were found to be closely related to liver damage indexes in TP-treated female mice. Metabolomics analysis further revealed that the CYP3A4 inducer dexamethasone improved the level of LPCs and amino acids, and defended against oxidative stress. On the contrary, pretreatment with the CYP3A4 inhibitor ketoconazole increased liver damage with most metabolites being markedly altered, especially carnitines. Among these metabolites, except for LPC18:2, LPC20:1 and arginine, dexamethasone and ketoconazole both affected oxidative stress induced by TP. The current study provides new mechanistic insights into the metabolic alterations, leading to understanding of the role of CYP3A4 in hepatotoxicity induced by TP.

12-year data on skin diseases in the Finnish Register of Occupational Diseases II: Risk occupations with special reference to allergic contact dermatitis.

BACKGROUND: Detailed epidemiological studies on occupational skin diseases (OSDs) are scarce. OBJECTIVES: To analyze risk occupations for OSDs in the Finnish Register of Occupational Diseases (FROD). METHODS: We retrieved numbers of OSD cases (excluding skin infections) for different occupations from the FROD in 2005-2016. In the FROD, Finnish ISCO-08-based classification of occupations was used since 2011, and the preceding ISCO-88-based version until 2010. We combined cases from the earlier and the later period using conversion tables provided by Statistics Finland. We included occupations with at least five cases and analyzed them in detail. We calculated incidence rates for OSDs and separately for allergic contact dermatitis (ACD) in different risk occupations using national labor force statistics. We also studied causes of ACD in these occupations. RESULTS: Risk occupations with the largest number of OSD cases included farmers, hairdressers, assistant nurses, cooks, cleaners, machinists, and nurses. Occupations with the highest incidences of OSDs comprised spray painters (23.8/10 000 person years), bakers (20.4), and dental technicians (19.0). Epoxy compounds and acrylates were prominent causes of ACD in occupations with the highest incidences of ACD. CONCLUSIONS: Uniform use of International Standard Classification of Occupations (ISCO) would facilitate comparisons of OSD figures in different countries.

12-year data on dermatologic cases in the Finnish Register of Occupational Diseases I: Distribution of different diagnoses and main causes of allergic contact dermatitis.

BACKGROUND: Skin diseases are among the most common occupational diseases, but detailed analyses on their epidemiology, diagnoses, and causes are relatively scarce. OBJECTIVES: To analyze data on skin disease in the Finnish Register of Occupational Diseases (FROD) for (1) different diagnoses and (2) main causes of allergic contact dermatitis (ACD). METHODS: We retrieved data on recognized cases with occupational skin disease (OSD) in the FROD from a 12-year-period 2005-2016 and used national official labor force data of the year 2012. RESULTS: We analyzed a total of 5265 cases, of which 42% had irritant contact dermatitis (ICD), 35% ACD, 11% contact urticaria/protein contact dermatitis (CU/PCD), and 9% skin infections. The incidence rate of OSD in the total labor force was 18.8 cases/100 000 person years. Skin infections concerned mainly scabies in health care personnel. Twenty-nine per cent of the ACD cases were caused by plastics/resins-related allergens, mainly epoxy chemicals. Other important causes for ACD were rubber, preservatives, metals, acrylates, and hairdressing chemicals. Cases of occupational ACD due to isothiazolinones reached a peak in 2014. CONCLUSION: Our analysis confirms that epoxy products are gaining importance as causes of OSD and the isothiazolinone contact allergy epidemic has started to wane.

Key role of organic cation transporter 2 for the nephrotoxicity effect of triptolide in rheumatoid arthritis.

Tripterygium wilfordii Hook. F. (TwHF), a traditional Chinese Medicine, is effective in treating rheumatoid arthritis (RA), but its severe nephrotoxicity limits its extensive application. The nephrotoxic mechanism of Triptolide (TP), the main pharmacological and toxic component of TwHF, has not been fully revealed. This study was designed to explore the nephrotoxicity of TP in the RA state and the potential molecular mechanism. A rat collagen-induced arthritis (CIA) model was constructed and administered with TP for 28 days in vivo. Results showed that the kidney injury induced by TP was aggravated in the CIA state, the concentration of TP in the renal cortex was higher than that of the medulla after TP administration in the CIA rats, and the expression of organic cation transporter 2 (Oct2) in kidney was up-regulated under CIA condition. Besides, rat kidney slice study demonstrated that TP was transported by Oct2 and this was confirmed by transient silencing and overexpression of OCT2 in HEK-293T cells. Furthermore, cytoinflammatory models on HK-2 and HEK-293T cell lines were constructed by exposure of TNF-α or IL-1ß to further explore the TP's renal toxicity. Results suggested that TNF-α exposure aggravated TP's toxicity and up-regulated the protein expression of OCT2 in both cell lines. TNF-α treatment also increased the function of OCT2 and finally OCT2 silencing confirmed OCT2 mediated nephrotoxicity of TP in HEK-293T cells. In summary, the exposure of TNF-α in RA state induced the expression of OCT2, which transported more TP into kidney cortex, subsequently exacerbated the kidney injury.

Human primary endothelial cells are impaired in nucleotide excision repair and sensitive to benzo[a]pyrene compared with smooth muscle cells and pericytes.

The endothelium represents the inner cell layer of blood vessels and is supported by smooth muscle cells and pericytes, which form the vessel structure. The endothelium is involved in the pathogenesis of many diseases, including the development of atherosclerosis. Due to direct blood contact, the blood vessel endothelium is inevitably exposed to genotoxic substances that are systemically taken up by the body, including benzo[a]pyrene, which is a major genotoxic component in cigarette smoke and a common environmental mutagen and human carcinogen. Here, we evaluated the impact of benzo[a]pyrene diol epoxide (BPDE), which is the reactive metabolite of benzo[a]pyrene, on the three innermost vessel cell types. Primary human endothelial cells (HUVEC), primary human smooth muscle cells (HUASMC) and primary human pericytes (HPC) were treated with BPDE, and analyses of cytotoxicity, cellular senescence and genotoxic effects were then performed. The results showed that HUVEC were more sensitive to the cytotoxic activity of BPDE than HUASMC and HPC. We further show that HUVEC display a detraction in the repair of BPDE-induced adducts, as determined through the comet assay and the quantification of BPDE adducts in post-labelling experiments. A screening for DNA repair factors revealed that the nucleotide excision repair (NER) proteins ERCC1, XPF and ligase I were expressed at lower levels in HUVEC compared with HUASMC and HPC, which corresponds with the impaired NER-mediated removal of BPDE adducts from DNA. Taken together, the data revealed that HUVEC exhibit an unexpected DNA repair-impaired phenotype, which has implications on the response of the endothelium to genotoxicants that induce bulky DNA lesions, including the development of vascular diseases resulting from smoking and environmental pollution.

Delayed occupational asthma from epoxy exposure.

BACKGROUND: A delayed asthma reaction occurring several hours after exposure is difficult to diagnose. AIMS: To confirm a delayed asthma reaction in five workers following epoxy exposure. CASE REPORT: Working conditions with exposure to epoxy encountered at the workplace were reproduced in a challenge chamber. Specific inhalation challenge (SIC) with epoxy was compared to a control challenge. All five cases had delayed a asthma response 6-15 h after epoxy exposure. CONCLUSIONS: Our study confirms that SIC is a useful tool in diagnosing delayed asthma response.

Aucubin, a natural iridoid glucoside, attenuates oxidative stress-induced testis injury by inhibiting JNK and CHOP activation via Nrf2 up-regulation.

BACKGROUND: Eucommia ulmoides has been used for many years as a successful strategy to treat male infertility. Aucubin (AU) is the active ingredient extracted from Eucommia ulmoides. However, its protective action and exact mechanism on testicular injury is not yet known. PURPOSE: Here, the protective effect and the mechanism of action of AU on testis damage under oxidative stress was investigated in vivo and in vitro. METHODS: As regard the in vivo experiment, male mice were divided into five groups and testicular injury model was established by Triptolide (TP) (120 µg/kg) intraperitoneal injection for two weeks. Animals in the treatment group were pretreated with an intraperitoneal injection of AU at different doses (5, 10 and 20 mg/kg) for 1 h and subsequently treated with TP (120 µg/kg). At the end of the experimental period, the testis was collected for biochemical and histological examination. As regard the in vitro experiment, Sertoli cells (SCs) were used to investigate the protective effect and mechanism of action of AU against disruption of the blood-testis-barrier (BTB) and apoptosis induced by TP via apoptosis detection, western blot, immunofluorescence analysis, and siRNA transient transfection. RESULTS: TP-treated animals showed testicular atrophy, BTB disruption, increased ROS levels and spermatogenic dysfunction. Pre-administration of AU resulted in a significant protection on keeping a normal testicular weight, sperm morphology, BTB integrity, and a normal level of oxidative stress markers and antioxidants. Furthermore, AU prevented apoptosis through an effective inhibition of PERK/CHOP and JNK dependent apoptosis pathway, as well as protected the integrity of BTB by up-regulating the expression of tight junction proteins (ZO-1, Occludin, Claudin-11) and gap junction protein (Cx43). The mechanistic study revealed that AU significantly triggered Nrf2 translocation, thus increasing nuclear Nrf2 accumulation and then induced antioxidant enzymes expression in the testis and SCs. Furthermore, Nrf2 silencing unsuccessfully reversed the increased CHOP and p-JNK expression induced by TP, abolishing the protective effect of AU. CONCLUSION: These results indicate that AU might be considered as a potential protective agent against testicular injury.

Skin exposure to epoxy chemicals in construction coating, assessed by observation, interviews, and measurements.

BACKGROUND: Epoxy resin systems (ERSs) are among the leading causes of occupational allergic contact dermatitis. OBJECTIVES: To identify riskful exposures and sources of skin exposure, and to quantify skin exposure to diglycidyl ether of bisphenol A (DGEBA) epoxy monomer, in construction coating work. METHODS: Skin exposure to epoxy chemicals was studied in 5 coating companies through (a) interviews and visual observation, (b) quantifying DGEBA on 12 workers' skin by tape-stripping, (c) measuring DGEBA on 23 surfaces by wipe-sampling, and (d) quantifying DGEBA in new sewage pipe. Acetone extracts of the tapes, wipes and sawdust from a newly hardened sewage pipe were analysed by gas chromatography/mass spectrometry. RESULTS: Identified riskful exposures were, for example, mixing ERSs, handling coating pots, and working above shoulder level. Epoxy stains on, for example, tools, equipment and clothing were seen in all workplaces. Protective gloves were of varying quality, and were not always suitable for chemicals. The amount of DGEBA on the workers' skin varied considerably. All screened tool handles were contaminated. Two-day-old epoxy sewage pipe contained 3.2% DGEBA. CONCLUSIONS: Construction coating entails skin contact with ERSs directly and via contaminated surfaces, personal protective equipment, and recently hardened epoxy materials. Observation is a useful method for assessing skin exposure in coating work.