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The biodiversity loss of phytoplankton with eutrophication has been reported in many aquatic ecosystems, e.g., water pollution and red tides. This phenomenon seems similar, but different from the paradox of enrichment via trophic interactions, e.g., predator-prey systems. We here propose the paradox of enrichment by induced competitive interactions using multiple contact process (a lattice Lotka-Volterra competition model). Simulation results demonstrate how eutrophication invokes more competitions in a competitive ecosystem resulting in the loss of phytoplankton diversity in ecological time. The paradox is enhanced under local interactions, indicating that the limited dispersal of phytoplankton reduces interspecific competition greatly. Thus, the paradox of enrichment appears when eutrophication destroys an ecosystem either by elevated interspecific competition within a trophic level and/or destabilization by trophic interactions. Unless eutrophication due to human activities is ceased, the world's aquatic ecosystems will be at risk [ABSTRACT FROM AUTHOR]

Abstract Objective  We conducted a phase I study of paclitaxel (PTX), carboplatin (CBDCA), and UFT in chemo-naive patients with advanced non-small cell lung cancer (NSCLC). Method  Twenty-one chemo-naive patients with advanced NSCLC were enrolled. The study was conducted as a phase I dose-escalation study of various doses of systemic PTX followed by CBDCA on day 1 and oral UFT (400 mg/m2) on days 1–5 and 8–12, with the cycle repeated at 21-day intervals. At least three patients were enrolled in each step. Results  The main toxicities were neutropenia and paresthesia, but were tolerable and reversible in all cases. Overall response rate was 57% (12 out of 21). The MTD was not reached at the highest dose level after the first cycle. Given previous recommends of PTX at 225 mg/m2 and CBDCA AUC 6 for two-drug therapy, the recommended dose for the phase II study under our regimen was set at PTX 225 mg/m2 on day 1, CBDCA AUC 6 on day 1, and UFT 400 mg/m2 on days 1–5 and 8–12. Conclusion  The combination of PTX, CBDCA, and UFT showed promising activity and acceptable toxicity in these chemo-naive patients, supporting the development of this combination as a feasible chemotherapeutic option for advanced NSCLC. [ABSTRACT FROM AUTHOR]

Many hereditary and sporadic neurodegenerative disorders are characterized by the accumulation of aberrant proteins In sporadic Parkinson's disease, representing the most prevalent movement disorder, oxidative and nitrosative stress are believed to contribute to disease pathogenesis, but the exact molecular basis for protein aggregation remains unclear. In the case of autosomal recessive- juvenile Parkinsonism, mutation in the E3 ubiquitin ligase protein parkin is linked to death of dopaminergic neurons. Here we show both in vitro and in vivo that nitrosative stress leads to S-nitrosylation of wild-type parkin and, initially, to a dramatic increase followed by a decrease in the E3 ligase-ubiquitin-proteasome degradative pathway. The initial increase in parkin's E3 ubiquitin ligase activity leads to autoubiquitination of parkin and subsequent inhibition of its activity, which would impair ubiquitination and clearance of parkin substrates. These findings may thus pro- vide a molecular link between free radical toxicity and protein accumulation in sporadic Parkinson's disease. [ABSTRACT FROM AUTHOR]

Transient forebrain ischemia induces a delayed neuronal death in the CA1 area of the hippocampus. However, the mechanism leading to this phenomenon has yet to be established. The authors used an mRNA differential-display method to isolate genes for which mRNA levels change only in the hippocampus during ischemia/reperfusion. They succeeded in identifying the product of one down-regulated gene as phosphatidylinositol 4-kinase (PI 4-K). Compared with control levels, PI 4-K mRNA expression in the hippocampus, but not the cerebral cortex, was significantly decreased by 30% and about 80% 1 and 7 days after ischemia/reperfusion, respectively. Interestingly, PI 4-K and PI bisphosphate levels were selectively decreased in the CA1 region, but not other regions, whereas TUNEL-positive cells could be detected 3 days after ischemia. Consistent with these results, PI 4-K expression was suppressed by hypoxia in SK-N-MC neuroblastoma cells before loss of cell viability. Overexpression of wild-type PI 4-K, but not the kinase-negative mutant of PI 4-K (K1789A), recovered the loss of viability induced by hypoxia. These findings strongly suggest that a prior decrease in PI 4-K and PI bisphosphate levels caused by brain ischemia/hypoxia is partly involved in delayed neuronal cell death. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) plays a physiological role in signal transduction and excess or chronic NO has toxic effects as an inflammatory mediator. NO reversibly forms protein S-nitrosylation and exerts toxicological functions related to disease progression. DNA methyltransferases, epigenome-related enzymes, are inhibited in enzymatic activity by S-nitrosylation. Therefore, excess or chronic NO exposure may cause disease by altering gene expression. However, the effects of chronic NO exposure on transcriptome are poorly understood. Here, we performed transcriptome analysis of A549, AGS, HEK293T, and SW48 cells exposed to NO (100 µM) for 48 hr. We showed that the differentially expressed genes were cell-specific. Gene ontology analysis showed that the functional signature of differentially expressed genes related to cell adhesion or migration was upregulated in several cell lines. Gene set enrichment analysis indicated that NO stimulated inflammation-related gene expression in various cell lines. This finding supports previous studies showing that NO is closely involved in inflammatory diseases. Overall, this study elucidates the pathogenesis of NO-associated inflammatory diseases by focusing on changes in gene expression. [ABSTRACT FROM AUTHOR]

Reactive carbonyl species (RCS), which are abundant in the environment and are produced in vivo under stress, covalently bind to nucleophilic residues such as Cys in proteins. Disruption of protein function by RCS exposure is predicted to play a role in the development of various diseases such as cancer and metabolic disorders, but most studies on RCS have been limited to simple cytotoxicity validation, leaving their target proteins and resulting physiological changes unknown. In this study, we focused on methyl vinyl ketone (MVK), which is one of the main RCS found in cigarette smoke and exhaust gas. We found that MVK suppressed PI3K-Akt signaling, which regulates processes involved in cellular homeostasis, including cell proliferation, autophagy, and glucose metabolism. Interestingly, MVK inhibits the interaction between the epidermal growth factor receptor and PI3K. Cys656 in the SH2 domain of the PI3K p85 subunit, which is the covalently binding site of MVK, is important for this interaction. Suppression of PI3K-Akt signaling by MVK reversed epidermal growth factor-induced negative regulation of autophagy and attenuated glucose uptake. Furthermore, we analyzed the effects of the 23 RCS compounds with structures similar to MVK and showed that their analogs also suppressed PI3K-Akt signaling in a manner that correlated with their similarities to MVK. Our study demonstrates the mechanism of MVK and its analogs in suppressing PI3K-Akt signaling and modulating physiological functions, providing a model for future studies analyzing environmental reactive species. [ABSTRACT FROM AUTHOR]

Objective: To treat advanced ovarian cancer, interval debulking surgery (IDS) is performed after 3 cycles each of neoadjuvant chemotherapy (NAC) and postoperative chemotherapy (IDS group). If we expect that complete resection cannot be achieved by IDS, debulking surgery is performed after administering additional 3 cycles of chemotherapy without postoperative chemotherapy (Add-C group). We evaluated the survival outcomes of the Add-C group and determined their serum cancer antigen 125 (CA125) levels to predict complete surgery. Methods: A retrospective chart review of all stage III and IV ovarian, fallopian tube, and peritoneal cancer patients treated with NAC in 2007-2016 was conducted. Results: About 117 patients comprised the IDS group and 26 comprised the Add-C group. Univariate and multivariate analyses revealed that Add-C group had an equivalent effect on progression-free survival (PFS; p=0.09) and overall survival (OS; p=0.94) compared with the IDS group. Multivariate analysis revealed that patients who developed residual disease after surgery had worse PFS (hazard ratio [HR]=2.18; 95% confidence interval [CI]=1.45-3.28) and OS (HR=2.33; 95% CI=1.43-3.79), and those who received <6 cycles of chemotherapy had worse PFS (HR=5.30; 95% CI=2.56-10.99) and OS (HR=3.05; 95% CI=1.46-6.38). The preoperative serum CA125 cutoff level was 30 U/mL based on Youden index method. Conclusions: Administering 3 additional cycles of chemotherapy followed by debulking surgery exhibited equivalent effects on survival as IDS followed by 3 cycles of postoperative chemotherapy. Preoperative serum CA125 levels of =30 U/mL may be a useful predictor of achieving complete surgery. [ABSTRACT FROM AUTHOR]

Apoptosis is one of the hallmarks of MeHg-induced neuronal cell death; however, its molecular mechanism remains unclear. We previously reported that MeHg exposure induces neuron-specific ER stress in the mouse brain. Excessive ER stress contributes to apoptosis, and CHOP induction is considered to be one of the major mechanisms. CHOP is also increased by MeHg exposure in the mouse brain, suggesting that it correlates with increased apoptosis. In this study, to clarify whether CHOP mediates MeHg-induced apoptosis, we examined the effect of CHOP deletion on MeHg exposure in CHOPknockout mice. Our data showed that CHOP deletion had no effect on MeHg exposure-induced weight loss or hindlimb impairment in mice, nor did it increase apoptosis or inhibit neuronal cell loss. Hence, CHOP plays little role in MeHg toxicity, and other apoptotic pathways coupled with ER stress may be involved in MeHg-induced cell death. [ABSTRACT FROM AUTHOR]

Our aim was to evaluate the effects of eradication and the incidence of secondary resistance by long-term low-dose daily 14-membered-ring macrolide therapy on Helicobacter pylori ( H. pylori) infection in patients with chronic lower respiratory tract inflammatory disease. In a retrospective analysis, we studied the seroprevalence of H. pylori IgG in 90 patients with inflammation of the lower respiratory tract (68 had been treated with macrolide and 22 served as controls). Then, in a prospective analysis, we evaluated the eradication effect of macrolide therapy by the decline of IgG values and the 13C-urea breath test. Only long-term macrolide use significantly affected the seroprevalence of H. pylori IgG. However, macrolide therapy did not reduce the H. pylori IgG values in 24 patients and did not eradicate H. pylori in 13C-urea breath tests. Chemosensitivity testing was performed on three H. pylori strains obtained by gastric biopsy from patients in whom the disease could not be eradicated. Only one strain demonstrated a resistant character. Daily long-term low-dose 14-membered-ring macrolide therapy for patients with lower respiratory inflammatory disease may not be sufficient to eradicate H. pylori, but some strains do not acquire a resistant nature. [ABSTRACT FROM AUTHOR]

The epidermal growth factor receptor (EGFR) is the most intensively investigated receptor tyrosine kinase. Several EGFR mutations and modifications have been shown to lead to abnormal self-activation, which plays a critical role in carcinogenesis. Environmental air pollutants, which are associated with cancer and respiratory diseases, can also activate EGFR. Specifically, the environmental electrophile 1,2-naphthoquinone (1,2-NQ), a component of diesel exhaust particles and particulate matter more generally, has previously been shown to impact EGFR signaling. However, the detailed mechanism of 1,2-NQ function is unknown. Here, we demonstrate that 1,2-NQ is a novel chemical activator of EGFR but not other EGFR family proteins. We found that 1,2-NQ forms a covalent bond, in a reaction referred to as N-arylation, with Lys80, which is in the ligand-binding domain. This modification activates the EGFR-Akt signaling pathway, which inhibits serum deprivation-induced cell death in a human lung adenocarcinoma cell line. Our study reveals a novel mode of EGFR pathway activation and suggests a link between abnormal EGFR activation and environmental pollutant-associated diseases such as cancer. [ABSTRACT FROM AUTHOR]

Objective: Gynecologists occasionally encounter synchronous endometrial and ovarian endometrioid carcinoma (SEO-EC) patients who show favorable prognosis than locally advanced or metastatic disease patients. This study aimed to elucidate prognostic factors of SEO-EC and identify patients who have a sufficiently low risk of recurrence without receiving adjuvant chemotherapy. Methods: We retrospectively reviewed 46 patients with pathologically confirmed SEO-EC who underwent surgery at the National Cancer Center Hospital between 1997 and 2016. Immunohistochemical evaluation of DNA mismatch repair (MMR) protein expression were performed for both endometrial and ovarian tumors. Patient outcomes were analyzed according to clinicopathologic factors. Results: From the multivariate analysis, cervical stromal invasion indicated a worse prognosis for progression-free survival (hazard ratio [HR]=6.85; 95% confidence interval [CI]=1.50-31.1) and overall survival (HR=6.95; 95% CI=1.15-41.8). Lymph node metastasis and peritoneal dissemination did not significantly affect survival. MMR deficiency was observed in 13 patients (28.3%), with both endometrial and ovarian tumors showing the same MMR expression status. MMR deficiency was not significantly associated with survival. Of 23 patients with lesions confined to only the uterine body and adnexa, only 2 had recurrence in the group receiving adjuvant therapy, while none of the 10 patients who did not receive adjuvant therapy had recurrence. Conclusion: SEO-EC patients with tumors localized to the uterine body and adnexa lesions had a low risk for recurrence and may not require adjuvant therapy. SEO-EC may have prognostic factors different from those of endometrial and ovarian cancer. [ABSTRACT FROM AUTHOR]

Objective: Uterine serous carcinoma (USC) is an aggressive type 2 endometrial cancer. Data on prognostic factors for patients with early-stage USC without adjuvant therapy are limited. This study aims to assess the baseline recurrence risk of early-stage USC patients without adjuvant treatment and to identify prognostic factors and patients who need adjuvant therapy. Methods: Sixty-eight patients with International Federation of Gynecology and Obstetrics (FIGO) stage I-II USC between 1997 and 2016 were included. All the cases did not undergo adjuvant treatment as institutional practice. Clinicopathological features, recurrence patterns, and survival outcomes were analyzed to determine prognostic factors. Results: FIGO stages IA, IB, and II were observed in 42, 7, and 19 cases, respectively. Median follow-up time was 60 months. Five-year disease-free survival (DFS) and overall survival (OS) rates for all cases were 73.9% and 78.0%, respectively. On multivariate analysis, cervical stromal involvement and positive pelvic cytology were significant predictors of DFS and OS, and ≥1/2 myometrial invasion was also a significant predictor of OS. Of 68 patients, 38 patients had no cervical stromal invasion or positive pelvic cytology and showed 88.8% 5-year DFS and 93.6% 5-year OS. Conclusion: Cervical stromal invasion and positive pelvic cytology are prognostic factors for stage I-II USC. Patients with stage IA or IB USC showing negative pelvic cytology may have an extremely favorable prognosis and need not receive any adjuvant therapies. [ABSTRACT FROM AUTHOR]