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The development of a rapid and accurate model for determining the genotoxicity and carcinogenicity of chemicals is crucial for effective cancer risk assessment. This study aims to develop a 1-day, single-dose model for identifying genotoxic hepatocarcinogens (GHCs) in rats. Microarray gene expression data from the livers of rats administered a single dose of 58 compounds, including 5 GHCs, was obtained from the Open TG-GATEs database and used for the identification of marker genes and the construction of a predictive classifier to identify GHCs in rats. We identified 10 gene markers commonly responsive to all 5 GHCs and used them to construct a support vector machine-based predictive classifier. In the silico validation using the expression data of the Open TG-GATEs database indicates that this classifier distinguishes GHCs from other compounds with high accuracy. To further assess the model's effectiveness and reliability, we conducted multi-institutional 1-day single oral administration studies on rats. These studies examined 64 compounds, including 23 GHCs, with gene expression data of the marker genes obtained via quantitative PCR 24 h after a single oral administration. Our results demonstrate that qPCR analysis is an effective alternative to microarray analysis. The GHC predictive model showed high accuracy and reliability, achieving a sensitivity of 91% (21/23) and a specificity of 93% (38/41) across multiple validation studies in three institutions. In conclusion, the present 1-day single oral administration model proves to be a reliable and highly sensitive tool for identifying GHCs and is anticipated to be a valuable tool in identifying and screening potential GHCs., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Arsenic is highly toxic to the human bladder. In the present study, we established a human bladder epithelial cell line that closely mimics normal human bladder epithelial cells by immortalizing primary uroplakin 1B-positive human bladder epithelial cells with human telomerase reverse transcriptase (HBladEC-T). The uroplakin 1B-positive human bladder epithelial cell line was then used to evaluate the toxicity of seven arsenicals (iAs V , iAs III , MMA V , MMA III , DMA V , DMA III , and DMMTA V ). The cellular uptake and metabolism of each arsenical was different. Trivalent arsenicals and DMMTA V exhibited higher cellular uptake than pentavalent arsenicals. Except for MMA V , arsenicals were transported into cells by aquaglyceroporin 9 (AQP9). In addition to AQP9, DMA III and DMMTA V were also taken up by glucose transporter 5. Microarray analysis demonstrated that arsenical treatment commonly activated the NRF2-mediated oxidative stress response pathway. ROS production increased with all arsenicals, except for MMA V . The activating transcription factor 3 (ATF3) was commonly upregulated in response to oxidative stress in HBladEC-T cells: ATF3 is an important regulator of necroptosis, which is crucial in arsenical-induced bladder carcinogenesis. Inorganic arsenics induced apoptosis while MMA V and DMA III induced necroptosis. MMA III , DMA V , and DMMTA V induced both cell death pathways. In summary, MMA III exhibited the strongest cytotoxicity, followed by DMMTA V , iAs III , DMA III , iAs V , DMA V , and MMA V . The cytotoxicity of the tested arsenicals on HBladEC-T cells correlated with their cellular uptake and ROS generation. The ROS/NRF2/ATF3/CHOP signaling pathway emerged as a common mechanism mediating the cytotoxicity and carcinogenicity of arsenicals in HBladEC-T cells., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Pregnant CD-1 mice received 200 ppm dimethylarsinic acid (DMA) in the drinking water from gestation day 8-18, and tumor formation was assessed in offspring at the age of 84 weeks. DMA elevated the incidence of lung adenocarcinoma (10.0%) and total tumors (33.3%) in male offspring compared to male control offspring (1.9 and 15.1%, respectively). DMA also elevated the incidence of hepatocellular carcinoma (10.0%) in male offspring compared to male control offspring (0.0%). DMA and its metabolites were detected in the lungs of transplacental DMA-treated neonatal mice. Transplacental DMA exposure increased cell proliferation in the epithelium in the lungs of both neonatal and 6-week-old male mice. Microarray and real-time PCR analyses detected high expression of keratin 8 (Krt8) in the lungs of both neonatal and 6-week-old DMA-treated mice. Western blot analysis indicated that DMA elevated methylation of histone H3K9, but not H3K27, in the lungs of male mice. Importantly, chromatin immunoprecipitation sequencing (ChIP-seq) analysis using an H3K9me3 antibody found differences in heterochromatin formation between mice exposed to DMA and the controls. Notably, ChIP-seq analysis also found regions of lower heterochromatin formation in DMA-treated mice, and one of these regions contained the Krt8 gene, agreeing with the results obtained by microarray analysis. High expression of Krt8 was also detected in adenoma and adenocarcinoma of the lung in male offspring. Overall, these data indicate that transplacental DMA treatment enhanced lung and liver carcinogenesis in male mice. In the lung, DMA caused aberrant methylation of histone H3K9, increased Krt8 expression, and enhanced cell proliferation.

Recent epidemiological studies have indicated that occupational exposure to the aromatic amine acetoaceto-o-toluidide (AAOT) was associated with a marked increase in urinary bladder cancers in Japan. However, little is known about the carcinogenicity of AAOT. To evaluate the urinary bladder carcinogenicity of AAOT, male and female F344 rats were treated with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) for 4 weeks followed by dietary administration of 0, 0.167, 0.5, or 1.5% AAOT for 31 weeks. The incidences and multiplicities of bladder tumors were significantly increased in the 0.5 and 1.5% groups of male and female rats in a dose-response manner. AAOT and seven downstream metabolites were detected in the urine of the male and female rats administered AAOT with levels increasing in a dose-dependent manner. The most abundant urinary metabolite of AAOT was the human bladder carcinogen o-toluidine (OTD), which was at least one order of magnitude higher than AAOT and the other AAOT metabolites. In a second experiment, male F344 rats were administered 0, 0.167, or 1.5% AAOT for 4 weeks. Gene expression analyses revealed that the expression of JUN and its downstream target genes was increased in the urothelium of male rats treated with 1.5% AAOT. These results demonstrate that AAOT promotes BBN-induced urinary bladder carcinogenesis in rats and suggest that overexpressed of JUN and its downstream target genes may be involved the bladder carcinogenicity of AAOT. In conclusion, AAOT, like other carcinogenic aromatic amines, is likely to be a carcinogen to the urinary bladder, and OTD metabolized from AAOT is the ultimate carcinogen.

Dammar resin is a natural food additive and flavoring substance present in many foods and drinks. The present study evaluates the chronic toxicity and carcinogenicity of dietary dammar resin in F344 rats. Dietary concentrations in the 52-week chronic toxicity study were 0, 0.03, 0.125, 0.5, or 2%. The major treatment-related deleterious effects were body weight suppression, increased relative liver weight, and low hemoglobin levels in males and females. Foci of cellular alteration in the liver were observed in the male 2% group, but not in any other group. The no-observed-adverse-effect level for chronic toxicity was 0.125% for males (200.4 mg/kg b.w./day) and females (241.9 mg/kg b.w./day). Dietary concentrations in the 104-week carcinogenicity study were 0, 0.03, 0.5, or 2%. Dammar resin induced hemorrhagic diathesis in males and females, possibly via the inhibition of extrinsic and intrinsic coagulation pathways. Incidences of hepatocellular adenomas and carcinomas were significantly increased in the male 2% group, but not in any other group. In the 4-week subacute toxicity study, the livers of male rat-fed diet-containing 2% dammar resin had increased levels of protein oxidation and increased the expression of two anti-apoptotic and seven cytochrome P450 (CYP) genes. There was also an increased tendency of oxidative DNA damage. These findings demonstrate that dammar resin is hepatocarcinogenic in male F344 rats and underlines the roles of inhibition of apoptosis, induction of CYP enzymes, and oxidative stress in dammar resin-induced hepatocarcinogenesis.

1,4-Dioxane is a widely used synthetic industrial chemical and its contamination of drinking water and food is a potential health concern. It induces liver tumors when administered in the drinking water to rats and mice. However, the mode of action (MOA) of the hepatocarcinogenicity of 1,4-dioxane remains unclear. Importantly, it is unknown if 1,4-dioxane is genotoxic, a key consideration for risk assessment. To determine the in vivo mutagenicity of 1,4-dioxane, gpt delta transgenic F344 rats were administered 1,4-dioxane at various doses in the drinking water for 16 weeks. The overall mutation frequency (MF) and A:T- to -G:C transitions and A:T- to -T:A transversions in the gpt transgene were significantly increased by administration of 5000 ppm 1,4-dioxane. A:T- to -T:A transversions were also significantly increased by administration of 1000 ppm 1,4-dioxane. Furthermore, the DNA repair enzyme MGMT was significantly induced at 5000 ppm 1,4-dioxane, implying that extensive genetic damage exceeded the repair capacity of the cells in the liver and consequently led to liver carcinogenesis. No evidence supporting other MOAs, including induction of oxidative stress, cytotoxicity, or nuclear receptor activation, that could contribute to the carcinogenic effects of 1,4-dioxane were found. These findings demonstrate that 1,4-dioxane is a genotoxic hepatocarcinogen and induces hepatocarcinogenesis through a mutagenic MOA in rats. Because our data indicate that 1,4-dioxane is a genotoxic carcinogen, we estimated the point of departure of the mutagenicity and carcinogenicity of 1,4-dioxane using the no-observed effect-level approach and the Benchmark dose approach to characterize its dose-response relationship at low doses.

Experiments using genetically engineered mice are regarded as indispensable to gaining a better understanding of the molecular pathophysiology in neuronal injury after subarachnoid hemorrhage (SAH). Therefore, mouse SAH models are becoming increasingly important. The circle of Willis perforation (cWp) model is the most frequently used mouse SAH model. We report and discuss the technical surgical approach, results, and difficulties associated with the cWp model, with reference to the existing literature. Our results largely confirmed previously published results. This model may be the first choice at present, because important pathologies can be reproduced in this model and most findings in the literature are based on it.

Background: To report long-term results of amniotic membrane transplantation (AMT)-assisted bleb revision for intractable late-onset bleb leak., Methods: Retrospective medical record review of six consecutive patients who underwent AMT-assisted bleb revision for late-onset bleb leak at the Kobe University hospital between December 2001 and March 2004., Results: The median (range) of age was 60 (20-77) years. All patients had a history of trabeculectomy with adjunctive use of 0.4 mg/ml mitomycin C. The median (range) of interval between the prior trabeculectomy and bleb leak was 15 (4-54) months. Preoperative intraocular pressure (IOP) was lower than 10 mmHg in two cases, while it was 25 mmHg or higher in three patients, who had a localized, ischemic, thin-wall leaking bleb circumscribed with extensively scarred tissue. The median (range) of follow-up after the AMT-assisted bleb revision was 49 (41-67) months. Postoperative IOP was well controlled in all patients without medication or with a maximum of three glaucoma medications. No patients presented recurrence of the bleb leak or AMT-related complications during entire follow-up. All patients showed at final visit a diffuse bleb which extended posteriorly beyond the conjunctival incision line., Conclusion: AMT-assisted bleb revision successfully treated intractable late-onset bleb leak. Further comparative studies are needed to confirm the present result.

Background: The thalamic cavernous angioma (CA) represents a neurosurgical challenge because of the critical neurologic functions of the thalamus and its surrounding structures and of their deep location inside the brain. Although the natural history of the thalamic CA remains undefined, several studies suggest the poor outcome of those patients especially if the symptomatic thalamic CA is treated conservatively. We describe the advantage of the paraculminar supracerebellar approach to the lesions in the brainstem., Objective: We studied the usefulness and the safety of the paraculminar supracerebellar infratentorial transtentorial approach for the patients with thalamic CA., Methods: One hundred and ninety two consecutive patients with CA were treated at the Department of Neurosurgery in the Zurich University Hospital between 1993 and 2003. Among these patients, we analyzed six patients (four female, mean age 43) with thalamic CA who underwent surgical removal with the paraculminar supracerebellar transtentorial approach. We retrospectively reviewed their medical charts, the neuroradiological images, and the operative notes/video records., Results: Four patients of the six presented with thalamic hemorrhage. CA existed in the left thalamus in four patients and in the right in two. Preoperative symptoms included sensorimotor disturbance (three cases), double vision (three cases), Parinaud syndrome (one case), and thalamic pain (one case). All patients had the thalamic CA completely removed without any postoperative deterioration., Conclusions: This study suggests that for the removal of thalamic cavernous angioma the paraculminar supracerebellar infratentorial transtentorial approach provides the spacious surgical field with reduced risks of damaging and sacrificing surrounding vascular and neuronal system. This approach could proffer one of the best and safest surgical routes for the radical removal of thalamic cavernous angioma.

Background: Pulmonary hypoplasia is a common cause of neonatal death. Despite the recent advances in prenatal diagnosis with US, the diagnosis of pulmonary hypoplasia is difficult. The recent application of fast MR imaging may provide additional valuable information., Objective: To evaluate pulmonary hypoplasia in the fetus with MRI., Materials and Methods: The subjects comprised 23 fetuses (18-40 weeks' gestation), including major anomalies diagnosed on fetal ultrasonography (n = 20), maternal abnormality (n = 2) and one normal twin. MRI was performed with a 1.5-T magnet and half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences. MR images were interpreted by three radiologists with special attention to the intensity of the lungs. The lung-to-liver intensity ratio was calculated by means of region-of-interest (ROI) analysis. The diagnosis of pulmonary hypoplasia depended on clinical, surgical and autopsy findings., Results: All fetuses with normal pulmonary development showed high intensity in the lung except for one fetus at 24 weeks' gestational age. All fetuses with pulmonary hypoplasia showed lung of low intensity., Conclusions: Low-intensity fetal lung on MRI imaging indicates pulmonary hypoplasia after 26 weeks' gestation.

The diagnostic values of hyperperfusion to the gallbladder fossa and the rim sign were retrospectively evaluated in 24 histopathologically proven cases of gallbladder disease. Although 12 of 13 patients (92%) with acute cholecystitis had nonvisualization of the gallbladder, the positive predictive value with this finding was 71%. However, when the finding was associated with hyperperfusion to the gallbladder fossa or the rim sign, the positive predictive value with both (90%) was markedly increased, compared to the prevalence ratio of 54%. Such a combination could be useful for preserving a high positive predictive value in the diagnosis of acute cholecystitis.