Association of fish and long-chain omega-3 fatty acids intakes with total and cause-specific mortality: prospective analysis of 421 309 individuals.

BACKGROUND: Prevailing dietary guidelines recommend regular fish consumption. However, the associations of fish and long-chain omega-3 polyunsaturated fatty acids (LCn-3 PUFAs) intakes with mortality remain unclear. OBJECTIVES: To examine the associations of fish and LCn-3 PUFAs intakes with total and cause-specific mortality. METHODS: A total of 240 729 men and 180 580 women from NIH-AARP Diet and Health Study were prospectively followed-up for 16 years. Dietary intakes were assessed using a validated NIH Diet History Questionnaire. RESULTS: A total of 54 230 men and 30 882 women died during 6.07 million person-years of follow-up. Higher fish and LCn-3 PUFAs intakes were significantly associated with lower total mortality (P < 0.0001). Comparing the highest with lowest quintiles of fish intake, men had 9% (95% confidence interval, 6-11%) lower total mortality, 10% (6-15%) lower cardiovascular disease (CVD) mortality, 6% (1-10%) lower cancer mortality, 20% (11-28%) lower respiratory disease mortality and 37% (17-53%) lower chronic liver disease mortality, while women had 8% (5-12%) lower total mortality, 10% (3-17%) lower CVD mortality and 38% (20-52%) lower Alzheimer's disease mortality. Fried fish consumption was not related to mortality in men whereas positively associated with mortality from all causes (P = 0.011), CVD and respiratory disease in women. LCn-3 PUFAs intake was associated with 15% and 18% lower CVD mortality in men and women across extreme quintiles, respectively. CONCLUSION: Consumption of fish and LCn-3 PUFAs was robustly associated with lower mortality from major causes. Our findings support current guidelines for fish consumption while advice on non-frying preparation methods is needed.

Bioequivalence assessment of metformin hydrochloride using a limited sampling strategy.

OBJECTIVE: The aim of this study was to develop a limited sampling strategy (LSS) that can be used to assess the bioequivalence of two metformin hydrochloride preparations. METHODS: Healthy subjects (n = 20) enrolled in the bioequivalence study received a single oral tablet of 1,000 mg metformin reference formulation or test formulation. The plasma concentration of metformin was determined using a validated HPLC method. A multiple linear regression analysis of the observed metformin Cmax and AUC0-24 versus the concentration of reference formulation was performed to develop LSS models for estimating these parameters. The models were internally validated by the Jackknife method. The best models were employed to assess the bioequivalence of the two metformin formulations. RESULTS: The linear relationship between pharmacokinetic parameters and a single concentration point was poor. Several models for the estimation of these parameters met the predefined criteria (r2 > 0.9). The Jackknife validation procedure revealed that LSS models based on two sampling times - C1.5 and C2 for Cmax; C4.0 and C10.0 for AUC0-24 - were accurate predictor of Cmax and AUC0-24. Prediction errors (PE) were less than 2%, and absolute prediction errors (AE) were less than 10%. PEs beyond 15% occurred in less than 5% of total samples. The bioequivalence assessment of the two metformin formulations, based on the best LSS models, provided results similar to those obtained using all the observed concentration-time data points, and indicated that the two metformin formulations were bioequivalent. CONCLUSION: A LSS method for assessing the bioequivalence of metformin formulations was established and proved to be applicable and accurate. This LSS method could be considered appropriate for a metformin bioequivalence study, providing an inexpensive cost of sampling acquisition and analysis.

Phenethyl isothiocyanate, a natural chemopreventive agent, activates c-Jun N-terminal kinase 1.

Phenethyl isothiocyanate (PEITC) and other structurally related compounds are potent chemopreventive agents in a number of experimental models of cancer in animals. The mechanisms of cancer protection by these agents are not clear but may involve the regulation of gene expression, such as that by Phase II detoxifying enzymes. To unveil the upstream signaling events that lead to the potential transcriptional activation of genes, we studied the involvement of mitogen-activated protein kinase, c-Jun N-terminal kinase 1 (JNK1), and extracellular signal-regulated kinase 1 and 2 cascades, which have been shown to mediate numerous types of extracellular signals. On treatment of human ovarian HeLa cells with PEITC, JNK1 activity was strongly induced in a dose- and time-dependent manner, whereas the activation of extracellular signal-regulated kinase 1 and 2 was not substantial. Furthermore, activation of JNK1 by PEITC was inhibited by pro-oxidants hydrogen peroxide and diamide, although these two pro-oxidants by themselves had opposing effects on JNK1 activity. Pretreatment with an antioxidant, N-acetyl-L-cysteine, had no effects on PEITC activation of JNK1. When comparing the kinetics of JNK1 activation by different isothiocyanates, PEITC elicited a sustained activation, whereas 3-phenylpropyl isothiocyanate and 4-phenylbutyl isothiocyanate stimulated transient activations. The responsiveness of JNK1 to PEITC, 3-phenylpropyl isothiocyanate, and 4-phenylbutyl isothiocyanate suggests the involvement of JNK1 in the regulation of Phase II detoxifying enzyme gene expression. Furthermore, different patterns of JNK1 induction by these isothiocyanates may contribute to their distinct chemopreventive efficacies in some animal tumor model studies.

Analytical studies on the impact of land reclamation on ground water flow.

Land reclamation has been a common practice to produce valuable land in coastal areas. The impact of land reclamation on coastal environment and marine ecology is well recognized and widely studied. It has not been recognized yet that reclamation may change the regional ground water regime, which may in turn modify the coastal environment, flooding pattern, and stability of slopes and foundations. This paper represents the first attempt to examine quantitatively the effect of reclamation on ground water levels. Analytical solutions are developed to study the ground water change in response to reclamation based on two hypothetical models. In the first model, the ground water flow regime changes only in the hillside around the reclamation areas. In the second model, the ground water regime changes in the entire hill. Both models assume that the ground water flow is in a steady state and satisfies the Dupuit assumptions. Hypothetical examples are used to demonstrate how the ground water level, ground water divide and ground water submarine discharge will change with the scale and hydraulic conductivity of the reclamation materials. The results show that the change of ground water regime depends mainly on the length of the reclaimed area and the values of hydraulic conductivity of the reclaimed materials. It is also seen that the reclamation may impact not only the ground water regime near the coast areas around the reclamation site, but also that in the coast areas opposite the reclamation area. A reclamation site near Tseung Kwan O in the New Territories in Hong Kong, China, is used as a case study to discuss the possible modification of the ground water system caused by reclamation.

Effect of abiraterone acetate plus prednisone on the QT interval in patients with metastatic castration-resistant prostate cancer.

PURPOSE: Abiraterone is the active metabolite of the pro-drug abiraterone acetate (AA) and a selective inhibitor of CYP17, a key enzyme in testosterone synthesis, and improves overall survival in postdocetaxel metastatic castration-resistant prostate cancer (mCRPC). This open-label, single-arm phase 1b study was conducted to assess the effect of AA and abiraterone on the QT interval. METHODS: The study was conducted in 33 patients with mCRPC. Patients received AA 1,000 mg orally once daily + prednisone 5 mg orally twice daily. Electrocardiograms (ECGs) were collected in triplicate using 12-lead Holter monitoring. Baseline ECGs were obtained on Cycle 1 Day-1. Serial ECG recordings and time-matched pharmacokinetic (PK) blood samples were collected over 24 h on Cycle 1 Day 1 and Cycle 2 Day 1. Serial PK blood samples were also collected over 24 h on Cycle 1 Day 8. RESULTS: After AA administration, the upper bound of the 2-sided 90 % confidence interval (CI) for the mean baseline-adjusted QTcF change was <10 ms; no patients discontinued due to QTc prolongation or adverse events. No apparent relationship between change in QTcF and abiraterone plasma concentrations was observed [estimated slope (90 % CI): 0.0031 (-0.0040, 0.0102)]. CONCLUSIONS: There is no significant effect of AA plus prednisone on the QT/QTc interval in patients with mCRPC.

Effect of trabectedin on the QT interval in patients with advanced solid tumor malignancies.

PURPOSE: The primary objective of this study was to access the potential effects of trabectedin on the QT/QTc interval in patients with locally advanced or metastatic solid tumors. METHODS: Patients (n = 75) who had received ≤3 previous lines of chemotherapy and had either relapsed or had progressive disease were enrolled. Patients were administered 3-h intravenous infusions of placebo (saline) on day 1 and trabectedin (1.3 mg/m(2)) on day 2. Time-matched serial triplicate ECG recordings and pharmacokinetic blood samples were collected over 24 h on both days. Heart rate corrected mean QT intervals and changes from predose baseline in QTc (ΔQTc) were assessed. The difference in ΔQTc between trabectedin and placebo was calculated at each time point (ΔΔQTc). RESULTS: The upper limits of the 90% confidence interval for ΔΔQTcF and ΔΔQTcB at all time points were less than the prespecified noninferiority margin of 10 ms (≤6.65 ms). No patient had a QTc > 500 ms or a time-matched increase from baseline in QTc > 60 ms at any time point. Regression analyses indicated ΔΔQTc was poorly correlated with trabectedin concentration. No adverse events suggestive of proarrhythmic potential were reported. CONCLUSION: Trabectedin did not prolong the QTc interval. Safety and pharmacokinetic profiles of trabectedin were similar to that observed in other ovarian and breast cancer studies.

Noninvasive delayed limb ischemic preconditioning attenuates myocardial ischemia-reperfusion injury in rats by a mitochondrial K(ATP) channel-dependent mechanism.

We previously demonstrated in rats that noninvasive delayed limb ischemic preconditioning (LIPC) induced by three cycles of 5-min occlusion and 5-min reperfusion of the left hind limb per day for three days confers the same cardioprotective effect as local ischemic preconditioning of the heart, but the mechanism has not been studied in depth. The aim of this project was to test the hypothesis that delayed LIPC enhances myocardial antioxidative ability during ischemia-reperfusion by a mitochondrial K(ATP) channel (mito K(ATP))-dependent mechanism. Rats were randomized to five groups: ischemia-reperfusion (IR)-control group, myocardial ischemic preconditioning (MIPC) group, LIPC group, IR-5HD group and LIPC-5HD group. The MIPC group underwent local ischemic preconditioning induced by three cycles of 5-min occlusion and 5-min reperfusion of the left anterior descending coronary arteries. The LIPC and LIPC-5HD groups underwent LIPC induced by three cycles of 5-min occlusion and 5-min reperfusion of the left hind limb using a modified blood pressure aerocyst per day for three days. All rats were subjected to myocardial ischemia-reperfusion injury. The IR-5HD and LIPC-5HD groups received the mito K(ATP) channel blocker 5-hydroxydecanoate Na (5-HD) before and during the myocardial ischemia-reperfusion injury. Compared with the IR-control group, both the LIPC and MIPC groups showed an amelioration of ventricular arrhythmia, reduced myocardial infarct size, increased activities of total superoxide dismutase, manganese-superoxide dismutase (Mn-SOD) and glutathione peroxidase, increased expression of Mn-SOD mRNA and decreased xanthine oxidase activity and malondialdehyde concentration. These beneficial effects of LIPC were prevented by 5-HD. In conclusion, delayed LIPC offers similar cardioprotection as local IPC. These results support the hypothesis that the activation of mito K(ATP) channels enhances myocardial antioxidative ability during ischemia-reperfusion, thereby contributing, at least in part, to the anti-arrhythmic and anti-infarct effects of delayed LIPC.

Regulation of human apolipoprotein A-I gene expression by equine estrogens.

Estrogen replacement therapies, such as conjugated equine estrogen (CEE, Premarin), reduce the risk of coronary heart disease among postmenopausal women. In the present study, a HepG2 stable cell line (HepG2/S) that harbors a luciferase reporter gene cassette with the human apolipoprotein A-I (apoA-I) promoter region was used to examine the activity of CEE components in modulating human apoA-I promoter activity. A number of estrogens modulated apoA-I promoter activity, with equilenin (Eqn) being the most potent. Eqn produced a 3-fold increase in apoA-I promoter activity and a similar increase in apoA-I mRNA without affecting its degradation rate. Nuclear runoff assays indicated that the transcription rate of the apoA-I gene was increased 2.5-fold in Eqn-treated cells. When HepG2/S cells were exposed to Eqn, apoA-I protein secretion increased by 80%, whereas the level of secreted apoA-II remained unchanged. Transient transfection studies with human apoA-I promoter constructs derived from pGL3-luciferase reporter plasmid were used to identify the cis-acting element involved in Eqn-mediated induction. The results demonstrated that the apoA-I electrophile/antioxidant response element (EpRE/ARE) might be responsible for the increase in apoA-I promoter activity by Eqn. Cotransfection experiments using estrogen receptor (ERalpha and/or ERbeta) expression vectors have indicated that neither receptor can potentiate the Eqn-mediated induction of apoA-I promoter activity. In addition, mobility shift analysis using antibody against either ERalpha or ERbeta cannot detect the presence of these receptors in the DNA-protein complex. The data indicate that Eqn can induce the promoter activity of the human apoA-I gene, leading to an increase in apoA-I mRNA levels and apoA-I protein secretion through an ER-independent pathway involving apoA-I EpRE/ARE.

Activation of mitogen-activated protein kinases by green tea polyphenols: potential signaling pathways in the regulation of antioxidant-responsive element-mediated phase II enzyme gene expression.

Green tea polyphenols, major constituents of green tea, are potent chemopreventive agents in a number of experimental models of cancer in animals. The mechanisms of cancer protection by these agents are not clear, but may involve modulation of the enzyme systems responsible for the detoxification of chemical carcinogens. The present studies show that a green tea polyphenol extract (GTP) induces chloramphenicol acetyltransferase (CAT) activity in human heptoma HepG2 cells transfected with a plasmid construct which contains an antioxidant-responsive element (ARE) and a minimal glutathione S-transferase Ya promoter linked to the CAT reporter gene. This indicates that GTP stimulates the transcription of Phase II detoxifying enzymes through the ARE. To explore the upstream signaling pathways leading to gene expression, we studied the involvement of the mitogen-activated protein kinases (MAPKs) extracellular signal-regulated kinase 2 (ERK2) and c-Jun N-terminal kinase 1 (JNK1). Potent activation of ERK2 was seen following treatment of HepG2 cells with different concentrations of GTP. Similar to ERK2, JNK1 was also strongly activated by treatment with GTP, although to a lesser extent and in a different dose-dependent fashion. Kinetic studies revealed that GTP activation of JNK1 was delayed and sustained, whereas ERK2 activation was rapid and transient. Furthermore, GTP treatment also increased mRNA levels of the immediate-early genes c-jun and c-fos, as determined by reverse transcriptase-coupled polymerase chain reaction. Taken together, these studies provide insights into the action of GTP and suggest that the stimulation MAPKs may be the potential signaling pathways utilized by GTP to activate ARE-dependent genes.

Activation of signal transduction kinases by tamoxifen.

PURPOSE: To study the signal transduction mechanisms of tamoxifen via the activation of MAPKs, JNK and ERK in order to understand its regulation of gene expression. METHODS: The effects of tamoxifen (TAM) on the activation of serine/threonine mitogen-activated protein kinase (MAPK, p42/ERK2) and the stress-activated protein kinases (p46 SAPK or c-Jun N-terminal kinase, JNK1) were evaluated using a human cervical epitheloid carcinoma HeLa cell line. RESULTS: TAM activated both JNK1 and ERK2 activities in a time- and dose-dependent manner in HeLa cells. The activation of JNK1 was enhanced when the cells were pretreated with prooxidant H2O2. CONCLUSIONS: These studies show that TAM activates the signal transduction kinases, JNK1 and ERK2, which may play important roles in the regulation of gene expression by TAM.