A body mass index ≥25 kg/m2 is associated with a poor prognosis in patients with acute pancreatitis: a study of Japanese patients.

BACKGROUND: In Asian population, there is limited information on the relevance between obesity and poor outcomes in acute pancreatitis (AP). The objective of this study was to examine the clinical impact of obesity based on body mass index (BMI) on prognosis of AP in Japanese patients. METHODS: A total of 116 patients with AP were enrolled in this study. Univariate and multivariate logistic regression analyses were performed to examine relations between BMI and patients' outcomes. Additionally, to investigate whether including obesity as a prognostic factor improved the predictive accuracy of a Japanese prognostic factor score (PF score), a receiver-operating characteristic (ROC) curve analysis of mortality was conducted. RESULTS: Multiple logistic regression analyses revealed that BMI =25 kg/m2 was associated with a significant higher mortality [odds ratio (OR)=15.8; 95% confidence interval (CI): 1.1-227; P=0.043]. The area under the ROC curve (AUC) for the combination of PF score and BMI =25 kg/m2 (AUC=0.881; 95% CI: 0.809-0.952) was higher than that for the PF score alone (AUC=0.820; 95% CI: 0.713-0.927) (P=0.034). CONCLUSIONS: The negative impact of a high BMI on the prognosis of AP was confirmed in a Japanese population. Including BMI =25 kg/m2 as an additional parameter to PF score enhanced the predictive value of the PF score for AP-related mortality.

The antioxidant N-acetyl cysteine suppresses lidocaine-induced intracellular reactive oxygen species production and cell death in neuronal SH-SY5Y cells.

BACKGROUND: The local anesthetic lidocaine can affect intra- and extra-cellular signaling pathways in both neuronal and non-neuronal cells, resulting in long-term modulation of biological functions, including cell growth and death. Indeed, lidocaine was shown to induce necrosis and apoptosis in vitro. While several studies have suggested that lidocaine-induced apoptosis is mitochondrial pathway-dependent, it remains unclear whether reactive oxygen species (ROS) are involved in this process and whether the observed cell death can be prevented by antioxidant treatment. METHODS: The effects of lidocaine and antioxidants on cell viability and death were evaluated using SH-SY5Y cells, HeLa cells, and HeLa cell derivatives. Cell viability was examined via MTS/PES ([3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt]/phenazine ethosulfate) assay. Meanwhile, cell apoptosis and necrosis were evaluated using a cell death detection assay with Annexin V-FITC and PI staining, as well as by assaying for caspase-3/7 and caspase-9 activity, and by measuring the release of lactate dehydrogenase, respectively. Mitochondrial transmembrane potential (ΔΨm) was assessed using the fluorescent probe tetramethylrhodamine ethyl ester. RESULTS: Lidocaine treatment resulted in suppression of the mitochondrial electron transport chain and subsequent attenuation of mitochondrial membrane potential, as well as enhanced ROS production, activation of caspase-3/7 and caspase-9, and induction of apoptosis and necrosis in SH-SY5Y cells in a dose- and time-dependent manner. Likewise, the anesthetics mepivacaine and bupivacaine also induced apoptosis in SH-SY5Y cells. Notably, the antioxidants N-acetyl cysteine (NAC) and Trolox successfully scavenged the mitochondria-derived ROS and suppressed local lidocaine-induced cell death. CONCLUSIONS: Our findings demonstrate that the local anesthetics lidocaine, mepivacaine, and bupivacaine inhibited the activity of mitochondria and induced apoptosis and necrosis in a dose-dependent manner. Furthermore, they demonstrate that treatment with the antioxidants NAC, Trolox, and GGA resulted in preservation of mitochondrial voltage and inhibition of apoptosis via suppression of caspase activation.

Impact of steroid medication before hospital admission on barotrauma in mechanically ventilated patients with acute respiratory distress syndrome in intensive care units.

PURPOSE: To investigate the association between steroid medication before hospital admission and barotrauma in mechanically ventilated patients with acute respiratory distress syndrome (ARDS). METHODS: An observational single-center retrospective study was conducted using patients admitted to the general intensive care unit (ICU) of a university hospital in Japan. We analyzed 149 mechanically ventilated patients with ARDS hospitalized between March 2008 and March 2011. ARDS was identified according to criteria from the Berlin Definition. Barotrauma was defined as pneumothorax, subcutaneous emphysema, or mediastinal emphysema occurring during mechanical ventilation in the ICU. The influence of steroid medication before hospital admission on barotrauma was studied using multiple logistic regression analysis. RESULTS: There were no differences in baseline patient characteristics except for congestive heart failure, peak pressure during mechanical ventilation, and steroid pulse therapy between the barotrauma and non-barotrauma groups. Logistic regression analysis showed that peak pressure ≥35 cmH2O was associated with barotrauma in patients with ARDS [odds ratio (OR), 17.34; P < 0.01], whereas steroid medication before hospital admission was not a significant factor for barotrauma (OR, 1.63; P = 0.51). CONCLUSIONS: Barotrauma in ARDS patients was associated with higher pressure during mechanical ventilation but not with steroid medication before hospital admission.

Comparison of dose-response relations between 4-week inhalation and intratracheal instillation of NiO nanoparticles using polimorphonuclear neutrophils in bronchoalveolar lavage fluid as a biomarker of pulmonary inflammation.

Inhalation studies and intratracheal instillation studies using laboratory animals are commonly conducted for pulmonary toxicity tests of nanomaterials. In our study, male Wister rats were exposed to nickel oxide (NiO) particles including a nano-scale, even for aerosols and suspensions, in a 4-week inhalation and intratracheal instillation. Using polymorphonuclear neutrophils (PMNs) in bronchoalveolar lavage fluid as a biomarker of inflammation, we attempted to quantify the relationship between responses to inhalation and intratracheal instillation of the nanoparticles, based on surface area doses. Four kinds of NiO suspension samples with different specific surface areas were singly injected via the tracheas of the rats. The relationship between the instilled doses and PMN production was examined 3 days and 1 month after the instillation. In parallel, 4-week inhalation studies, using two of the suspensions, were conducted for aerosols generated by a pressurized nebulizer. NiO samples induced PMN responses 3 days after instillation according to the surface area doses, but not the mass doses, as has been reported in many studies. When the same NiO samples were tested in a 4-week inhalation and intratracheal instillation, the amount of pulmonary deposition of the sample after the 4-week inhalation, and an intratracheally instilled dose about ten-times higher, induced similar PMN responses 3 days after termination of inhalation and instillation. Using the relationship between these responses to 4-week inhalation and intratracheal instillation, it may be possible to estimate what aerosol concentrations of other nanomaterials might cause the same responses of PMN production as intratracheal instillation tests.

[A case of Rh incompatible transfusion after use of anti-D immunoglobulin for unexpected intraoperative massive hemorrhage].

A 69-year-old woman with Rh-negative blood type was scheduled for total pelvic exenteration. Despite having prepared suspected amount of blood, we were forced to transfuse Rh-positive blood after use of anti-D immunoglobulin (0.25 mg) for unexpected massive hemorrhage. Although some strategies (blood-withdrawal system, vascular embolization, discontinuation of operation, et al.) for reduction of incompatible transfusion were considered, we fortunately could acquire additional matched blood after transfusion of Rh-positive blood (4 units), and the operation was completed. On postoperative days 1-2, we administered anti-D immunoglobulin (each 0.25 mg) prophylactically. It is reported that 0.02 mg immunoglobulin prevents sensitization against 1 ml transfused red cells. In this case, total dose of immunoglobulin was not enough, but antiD antibody was not detected over 6 months nonetheless. Two reasons were speculated for lack of anti-D anti body; this patient was immune-suppressed for chemoradiation against rectal cancer, and remaining Rh-positive red cells in her body were of small amount because of massive hemorrhage. Anyway, anti-D globulin administration with the aim of complete neutralization against incompatible transfusion is considered impossible, as there are few Rh-negative people in Japan. It is necessary to prepare sufficient matched blood for major surgery of Rh-negative patients, and to consider above-described strategies. Unavoidable Rh incompatible transfusion needs long-term (about 6 months) follow-up based on erythrocyte life-span and time of antibody production.

Using nanopore sequencing to identify fungi from clinical samples with high phylogenetic resolution.

The study of microbiota has been revolutionized by the development of DNA metabarcoding. This sequence-based approach enables the direct detection of microorganisms without the need for culture and isolation, which significantly reduces analysis time and offers more comprehensive taxonomic profiles across broad phylogenetic lineages. While there has been an accumulating number of researches on bacteria, molecular phylogenetic analysis of fungi still remains challenging due to the lack of standardized tools and the incompleteness of reference databases limiting the accurate and precise identification of fungal taxa. Here, we present a DNA metabarcoding workflow for characterizing fungal microbiota with high taxonomic resolution. This method involves amplifying longer stretches of ribosomal RNA operons and sequencing them using nanopore long-read sequencing technology. The resulting reads were error-polished to generate consensus sequences with 99.5-100% accuracy, which were then aligned against reference genome assemblies. The efficacy of this method was explored using a polymicrobial mock community and patient-derived specimens, demonstrating the marked potential of long-read sequencing combined with consensus calling for accurate taxonomic classification. Our approach offers a powerful tool for the rapid identification of pathogenic fungi and has the promise to significantly improve our understanding of the role of fungi in health and disease.

Successful management of pregnancy-associated thrombotic thrombocytopenic purpura by monitoring ADAMTS13 activity.

Thrombotic thrombocytopenic purpura (TTP) during pregnancy is very rare and is caused by an absent or severely depleted ADAMTS13 (a disintegrin-like and metallopeptidase with thrombospondin type 1 motif, 13). A 37-year-old multigravida woman developed TTP with severe anemia and thrombocytopenia at 22 weeks' gestation. ADAMTS13 activity was markedly decreased to 3% and ADAMTS13 inhibitor was positive, leading to a definitive diagnosis of TTP. She was successfully treated by plasmapheresis six times, resulting in symptomatic relief. Close follow up with periodic ADAMTS13 measurement facilitated plasmapheresis at appropriate points at a minimum frequency during pregnancy. Because of intrauterine growth retardation from 28 weeks' gestation, an elective cesarean section was performed at 30 weeks' gestation. After delivery, the mother and child showed no appreciable problem. To our knowledge, this is the first report of successful management for pregnancy-associated TTP by monitoring ADAMTS13 activity during pregnancy and the postpartum period.

Biopersistence of potassium hexatitanate in inhalation and intratracheal instillation studies.

An inhalation study and an intratracheal instillation study were conducted to evaluate the biological effects of the new chemical, potassium hexatitanate (PH). For the inhalation study, Wistar male rats were exposed to PH for 6 h a day, 5 days a week for a period of 3 months. The mass median aerodynamic diameter of PH in the exposure chamber was 4.9 µm (1.8) and the mean concentration during the exposure was 2.3 ± 0.1 mg/m(3). After the 3-month inhalation period, rats were dissected at 3 days, 1 month, 3 months, 6 months, and 12 months. The initial PH burden was 0.17 ± 0.03 mg/lung, and this decreased exponentially up to 6 months after inhalation. After 6 months, the rate at which the burden decreased slowed. The biological halftime up to 6 months after exposure was 2.3 months. No difference was found in the dimension of PH fibers in the lung during the observation period and the histopathological examination found no remarkable inflammation or fibrosis. For the intratracheal instillation study, the rats were given a single 2-mg dose of PH suspended in a 0.4 ml saline solution. The geometric mean diameter was 4.3 µm (2.3). After instillation, the rats were dissected at 3 days to 12 months. The PH burden in the lungs decreased exponentially and the biological halftime was 3.1 months. The results of the dimension of PH and histopathological findings were the same as those for the inhalation study. These data suggest that the toxicity of PH in the lung is low in these doses.

Pathological features of rat lung following inhalation and intratracheal instillation of C(60) fullerene.

We evaluated the pulmonary pathological features of rats that received a single intratracheal instillation and a 4-week inhalation of a fullerene. We used fullerene C(60) (nanom purple; Frontier Carbon Co. Ltd, Japan) in this study. Male Wistar rats received intratracheal dose of 0.1, 0.2, or 1 mg of C(60), and were sacrificed at 3 days, 1 week, 1 month, 3 months, 6 months, and 12 months. In the inhalation study, Wistar rats received C(60) or nickel oxide by whole-body inhalation for 6 h/day, 5 days/week, 4 weeks, and were sacrificed at 3 days, 1 month, and 3 months after the end of exposure. During the observation period, no tumors or granulomas were observed in either study. Histopathological evaluation by the point counting method (PCM) showed that a high dose of C(60) (1 mg) instillation led to a significant increase of areas of inflammation in the early phase (until 1 week). In the inhalation study of the C(60)-exposed group, PCM evaluation showed significant changes in the C(60)-exposed group only at 3 days after exposure; after 1 month, no significant changes were observed. The present study demonstrated that the pulmonary inflammation pattern after exposure to well-characterized C(60) via both intratracheal and inhalation instillation was slight and transient. These results support our previous studies that showed C(60) has no significant adverse effects in intratracheal and inhalation instillation studies.

[Filtration performance of dust respirators against nanoparticles].

It is necessary to consider protective measures, such as dust respirators, against the inhalation of nanoparticle aerosols. Industrial hygienists and workers handling nanomaterials are concerned about the filteration performance of dust respirators in protecting against nanoparticles, the size of which is less than 100 nm. We developed a filteration performance evaluating system using titanium dioxide nanoparticle aerosols ranging from 15 to 220 nm in diameter. The system, which includes two models of DS1 class and four models of DS2 class, was used to measure the collection efficiencies of dust respirators. These tested dust respirators had been certified by the Japanese government. In the dust respirators, there were no samples that showed less collection efficiency than the standard certified collection efficiency (80% for DS1 and 95% for DS2).

Polysulfide inhibits hypoxia-elicited hypoxia-inducible factor activation in a mitochondria-dependent manner.

In cellular signaling, the diverse physiological actions of biological gases, including O2, CO, NO, and H2S, have attracted much interest. Hypoxia-inducible factors (HIFs), including HIF-1 and HIF-2, are transcription factors that respond to reduced intracellular O2 availability. Polysulfides are substances containing varying numbers of sulfur atoms (H2Sn) that are generated endogenously from H2S by 3-mercaptopyruvate sulfurtransferase in the presence of O2, and regulate ion channels, specific tumor suppressors, and protein kinases. However, the effect of polysulfides on HIF activation in hypoxic mammalian cells is largely unknown. Here, we have investigated the effect of polysulfide on cells in vitro. In established cell lines, polysulfide donors reversibly reduced cellular O2 consumption and inhibited hypoxia-induced HIF-1α protein accumulation and the expression of genes downstream of HIFs; however, these effects were not observed in anoxia. In Von Hippel-Lindau tumor suppressor (VHL)- and mitochondria-deficient cells, polysulfides did not affect HIF-1α protein synthesis but destabilized it in a VHL- and mitochondria-dependent manner. For the first time, we show that polysulfides modulate intracellular O2 homeostasis and regulate HIF activation and subsequent hypoxia-induced gene expression in a VHL- and mitochondria-dependent manner.

Cigarette Smoke Extract Activates Hypoxia-Inducible Factors in a Reactive Oxygen Species-Dependent Manner in Stroma Cells from Human Endometrium.

Cigarette smoking (CS) is a major contributing factor in the development of a large number of fatal and debilitating disorders, including degenerative diseases and cancers. Smoking and passive smoking also affect the establishment and maintenance of pregnancy. However, to the best of our knowledge, the effects of smoking on the human endometrium remain poorly understood. In this study, we investigated the regulatory mechanism underlying CS-induced hypoxia-inducible factor (HIF)-1α activation using primary human endometrial stromal cells and an immortalized cell line (KC02-44D). We found that the CS extract (CSE) increased reactive oxygen species levels and stimulated HIF-1α protein stabilization in endometrial stromal cells, and that CS-induced HIF-1α-dependent gene expression under non-hypoxic conditions in a concentration- and time-dependent manner. Additionally, we revealed the upregulated expression of a hypoxia-induced gene set following the CSE treatment, even under normoxic conditions. These results indicated that HIF-1α might play an important role in CS-exposure-induced cellular stress, inflammation, and endometrial remodeling.

Inflammogenic effect of well-characterized fullerenes in inhalation and intratracheal instillation studies.

BACKGROUND: We used fullerenes, whose dispersion at the nano-level was stabilized by grinding in nitrogen gas in an agitation mill, to conduct an intratracheal instillation study and an inhalation exposure study. Fullerenes were individually dispersed in distilled water including 0.1% Tween 80, and the diameter of the fullerenes was 33 nm. These suspensions were directly injected as a solution in the intratracheal instillation study. The reference material was nickel oxide in distilled water. Wistar male rats intratracheally received a dose of 0.1 mg, 0.2 mg, or 1 mg of fullerenes and were sacrificed after 3 days, 1 week, 1 month, 3 months, and 6 months. In the inhalation study, Wistar rats were exposed to fullerene agglomerates (diameter: 96 +/- 5 nm; 0.12 +/- 0.03 mg/m3; 6 hours/days for 5 days/week) for 4 weeks and were sacrificed at 3 days, 1 month, and 3 months after the end of exposure. The inflammatory responses and gene expression of cytokine-induced neutrophil chemoattractants (CINCs) were examined in rat lungs in both studies. RESULTS: In the intratracheal instillation study, both the 0.1 mg and 0.2 mg fullerene groups did not show a significant increase of the total cell and neutrophil count in BALF or in the expression of CINC-1,-2alphabeta and-3 in the lung, while the high-dose, 1 mg group only showed a transient significant increase of neutrophils and expression of CINC-1,-2alphabeta and -3. In the inhalation study, there were no increases of total cell and neutrophil count in BALF, CINC-1,-2alphabeta and-3 in the fullerene group. CONCLUSION: These data in intratracheal instillation and inhalation studies suggested that well-dispersed fullerenes do not have strong potential of neutrophil inflammation.

Airway management in an infant with double aortic arch.

A 2-month old male was admitted due to repeated cyanotic attacks. He had suffered from stridor and retractive breathing since birth. Double aortic arch was diagnosed and the vascular ring formed by the double aortic arch was compressing the trachea. Multirow detector computed tomography showed that he had a right-dominant double aortic arch with left ductus arteriosus and an aberrant left subclavian artery, and that the narrowest part of the trachea, where the diameter was 2.0 mm, was located 9.0 mm above the carina. Airway management in patients with extreme narrowing of the trachea is challenging for anesthesiologists. He was scheduled for ligation and division of the left aortic arch and ductus arteriosus. In the operating theater, anesthesia was slowly induced with sevoflurane (0-4%) in oxygen. After mask ventilation was confirmed to be adequate, a 4.0 mm internal diameter endotracheal tube (ETT) was inserted and advanced smoothly beyond the tracheal stenosis. The tip of the ETT was placed just above the carina using a fiber optic bronchoscope (fiberscope) that was passed through the ETT. Since mechanical ventilation was adequate, vecuronium was administered. Surgery was conducted in the right lateral position and using a left thoracotomy approach. Anesthesia was maintained with sevoflurane (2-3%). After positioning, right one-lung ventilation was performed unexpectedly. However, anesthetic management was achieved without difficult ventilation during surgery. The tip of the ETT was pulled past the stenotic part before transfer to the intensive care unit (ICU). A patent trachea during spontaneous breathing under CPAP (5 and 2 cmH(2)O) was confirmed with a bronchofiberscope in the ICU. After weaning from mechanical ventilation, he had the persistence of mild stridor despite improvement of respiratory symptoms.

The intravenous anesthetic propofol inhibits lipopolysaccharide-induced hypoxia-inducible factor 1 activation and suppresses the glucose metabolism in macrophages.

PURPOSE: Hypoxia-inducible factor 1 (HIF-1) is a master transcription factor of hypoxia-induced gene expression. Anesthetics and perioperative drugs have been reported to affect HIF-1 activity. However, the effect of propofol on HIF-1 activity is not well documented. In this study, we investigated the effect of propofol on HIF-1 activation using macrophage-differentiated THP-1 cells. METHODS: Cells were exposed to lipopolysaccharide (LPS) under 20 or 1% O(2) conditions with or without propofol treatment. The cell lysate was subjected to Western blot analysis using anti-HIF-1alpha and HIF-1beta antibodies. HIF-1-dependent gene expression was investigated by quantitative real-time reverse-transcriptase PCR analysis and luciferase assay. The amount of cellular lactate and ATP was assayed. RESULTS: Propofol suppressed HIF-1alpha protein accumulation induced by LPS, but not by hypoxia in the THP-1 cells in a dose-dependent manner by inhibiting the neo-synthesis of HIF-1alpha protein. Induction of the HIF-1 downstream gene expression including glucose transporter 1, enolase 1, lactate dehydrogenase A, pyruvate dehydrogenase kinase-1 and vascular endothelial growth factor was inhibited by propofol. Propofol suppressed LPS-induced lactate accumulation and ATP content in THP-1 cells. CONCLUSION: Our experimental results indicate that propofol inhibits HIF-1 activation and downstream gene expression induced by LPS and suppressed HIF-1-dependent glucose metabolic reprogramming. HIF-1 suppression by propofol in macrophages may explain molecular mechanisms behind the inhibitory effect of propofol on cellular inflammatory responses.

Changes over time in pulmonary inflammatory response in rat lungs after intratracheal instillation of nickel oxide nanoparticles.

OBJECTIVE: Nickel oxide nanoparticles (NiONPs) are representative metal oxide NPs and are categorized as an insoluble nickel compound. Our previous studies suggested that NiONPs have more pulmonary toxicity than micron-sized NiO because they may dissolve slowly and produce many more Ni ions. We confirmed the hypothesis that the slow dissolution of NiONPs induces a change in inflammatory response over time. METHOD: We reanalyzed our previous data on intratracheally instilled NiONP to rats and focused on Ni retention in the lungs and the lung weight ratio for each rat to the mean of control rat lungs. We also measured the solubility of NiONPs and micron-sized NiO samples by means of an artificial lysosomal fluid (ALF, pH 4.5). RESULTS: The in vivo test of instilled NiONPs resulted in the biomarkers reaching their peak values at 1 week or 1 month, and not at 3 days, after instillation. We found that as the NiO mass in the lung increased, the lung weight ratios tended to increase. The relationships shifted to more toxic at 3 days to 1 month (P < .01). Compared to the dissolution of NiONPs in the ALF that took roughly 1 week, the dissolution of NiONPs in vivo was take about 1 month or more. CONCLUSION: When intratracheally instilled NiONPs dissolve slowly in the phagolysosomes of alveolar macrophages (AM), the resulting Ni ions cause the AM to transform into foamy cells at 1 month, and the inflammatory response persists even at 3 months after instillation.

Pathological features of different sizes of nickel oxide following intratracheal instillation in rats.

Focusing on the "size" impact of particles, the objective of this study was to analyze morphological and qualitative changes over time in the development of inflammation and collagen deposition in lung tissue after intratracheal instillation of two sizes of nickel oxide in rats, in comparison with the results of instillation of crystalline silica and titanium dioxide. The fine-sized nickel oxide sample (nNiOm: median diameter of agglomerated particles 0.8 microm) was prepared from crude particles of nickel oxide (median diameter of primary particle 27 nm) by liquid-phase separation. Another samples of micrometer-sized nickel oxide (NiO: median diameter of particles 4.8 microm), crystalline silica (Min-U-SIL-5; geometric mean diameter 1.6 microm, geometric standard deviation [GSD] 2.0), and TiO(2) (geometric mean diameter 1.5 microm, GSD 1.8) were also used. Well-sonicated samples of 2 mg per 0.4 ml saline or saline alone (control) were intratracheally instilled into Wistar rats (males, 10 wk old). Bronchoalveolar lavage fluid (BAL)F and lung tissue were examined at 3 days, 1 wk, 1 mo, 3 mo, and 6 mo after instillation, from 5 rats of each group. Histopathological findings showed that the infiltration of macrophages or polymorphonuclear cells and the alveolitis in rats treated with nNiOm were remarkable over time and similar to the effects of crystalline silica. The numbers of total cells in BALF and the percentage of plymorphonuclear leukocytes (PMNs) also increased in the nNiOm group and silica group. The point counting method (PCM) showed a significant increase of inflammatory area, with the peak at 3 mo after instillation in the nNiOm group. In contrast, NiO treatment showed only a slight inflammatory change. Collagen deposition in two regions in the lung tissue (alveolar duct and pleura) showed an increasing collagen deposition rate in nNiOm at 6 mo. Our results suggest that submicrometer nano-nickel oxide is associated with greater toxicity, as for crystalline silica, than micrometer-sized nickel oxide. Biological effects of factors of particle size reduction, when dealing with finer particles such as nanoparticles, were reconfirmed to be important in the evaluation of respirable particle toxicity.

Effect of polymerized toner on rat lung in chronic inhalation study.

In order to evaluate the chronic effect of polymerized toner particles on the lung, inflammation- and fibrosis-related genes were analyzed and 8-hydroxydeoxyguanosine (8-OHdG) was examined by using the lung tissue of rats subjected to 24 months of toner inhalation exposure. Wistar female rats were divided into four groups (5 weeks old, 30 rats in each): the high concentration exposure group (16.3 +/- 0.6 mg/m(3)), the medium concentration exposure group (4.4 +/- 0.3 mg/m(3)), the low concentration exposure group (1.6 +/- 0.2 mg/m(3)), and the control group (clean air). The material used was black toner, and its aerodynamic diameter in the exposure chamber was 3.0 microm. The rats were exposed to the material for 24 months (6 hours/day, 5 days/week) and dissected after the exposure period. RNA was extracted from one lung and the gene expression related to inflammation and fibrosis. Matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinase-2 (TIMP-2), and type I collagen were analyzed according to the ratio of each gene/beta-actin. Also, 8-OHdG level in the lung tissue was measured by HPLC with an electrochemical detector. Small fibrotic foci were found in the toner exposed groups; however, progressive or irreversible fibrosis was not found. The incidence of small fibrotic foci and cell aggregation increased in a dose-dependent manner. There were no significant differences of expression of MMP-2, TIMP-2, and type I collagen between the control group and each exposed group. Lung tumors did not develop in each group. A significant production of 8-OHdG was not observed in the toner exposed groups. In conclusion, toner produced by polymerization was not associated with evidence of carcinogenesis in this experiment.

Expression of cytokine-induced neutrophil chemoattractant in rat lungs by intratracheal instillation of nickel oxide nanoparticles.

Since nanoparticles easily agglomerate to form larger particles, it is important to maintain the size of their agglomerates at the nano-level to evaluate the harmful effect of the nanoparticles. We prevented agglomeration of nickel oxide nanoparticles by ultrasound diffusion and filtration, established an acute exposure model using animals, and examined inflammation and chemokine expression. The mass median diameter of nickel oxide nanoparticle agglomerates suspended in distilled water for intratracheal instillation was 26 nm (8.41 nm weighted average surface primary diameter). Male Wistar rats received intratracheal instillation of nickel oxide nanoparticles at 0.1 mg (0.33 mg/kg) or 0.2 mg (0.66 mg/kg), and were dissected 3 days, 1 week, 1 month, 3 months, and 6 months after the instillation. The control group received intratracheal instillation of distilled water. Three chemokines (cytokine-induced neutrophil chemoattractant-1 (CINC-1), CINC-2alphabeta, and CINC-3) in the lung tissue and bronchoalveolar lavage fluid (BALF) were determined by quantitative measurement of protein by ELISA. Both CINC-1 and CINC-2alphabeta concentration was elevated from day 3 to 3 months in lung tissue and from day 3 to 6 months in BALF. On the other hand, CINC-3 was elevated on day 3 in both lung tissue and BALF, and then decreased. The total cell and neutrophil counts in BALF were increased from day 3 to 3 months. In lung tissue, infiltration of mainly neutrophils and alveolar macrophages was observed from day 3 to 6 months in alveoli. These results suggest that CINC was involved in lung injury by nickel oxide nanoparticles.

n-Propyl gallate activates hypoxia-inducible factor 1 by modulating intracellular oxygen-sensing systems.

HIF-1 (hypoxia-inducible factor 1) is a master regulator of cellular adaptive responses to hypoxia. The expression and transcriptional activity of the HIF-1alpha subunit is stringently controlled by intracellular oxygen tension through the action of prolyl and asparaginyl hydroxylases. In the present study we demonstrate that PG (n-propyl gallate) activates HIF-1 and expression of its downstream target genes under normoxic conditions in cultured cells and in mice. The stability and transcriptional activity of HIF-1alpha are increased by PG. PG treatment inhibits the interaction between HIF-1alpha and VHL (von Hippel-Lindau protein) and promotes the interaction between HIF-1alpha and p300, indicating that PG inhibits the activity of both prolyl and asparaginyl HIF-1alpha hydroxylases. We conclude that PG activates HIF-1 and enhances the resultant gene expression by directly affecting the intracellular oxygen sensing system in vitro and in vivo and that PG represents a lead compound for the development of a non-toxic activator of HIF-1.