Contribution margin model applied to the marketing planning of a container liner carrier

The implementation of confidential contracts between a container liner carrier and its customers, because of the Ocean Shipping Reform Act (OSRA) 1998, demands a revision in the methodology applied in the carrier's planning of marketing and sales. The marketing and sales planning process should be more scientific and with a better use of operational research tools considering the selection of the customers under contracts, the duration of the contracts, the freight, and the container imbalances of these contracts are basic factors for the carrier's yield. This work aims to develop a decision support system based on a linear programming model to generate the business plan for a container liner carrier, maximizing the contribution margin of its freight.

Multidisciplinary optimization of a catamaran's hydrofoil design with dynamic response surface and distributive processing

This paper presents a rational approach to the design of a catamaran's hydrofoil applied within a modern context of multidisciplinary optimization. The approach used includes the use of response surfaces represented by neural networks and a distributed programming environment that increases the optimization speed. A rational approach to the problem simplifies the complex optimization model; when combined with the distributed dynamic training used for the response surfaces, this model increases the efficiency of the process. The results achieved using this approach have justified this publication.

Intestinal Anti-Inflammatory Activity of Baccharis dracunculifolia in the Trinitrobenzenesulphonic Acid Model of Rat Colitis

Baccharis dracunculifolia DC (Asteraceae) is a Brazilian medicinal plant popularly used for its antiulcer and anti-inflammatory properties. This plant is the main botanical source of Brazilian green propolis, a natural product incorporated into food and beverages to improve health. The present study aimed to investigate the chemical profile and intestinal anti-inflammatory activity of B. dracunculifolia extract on experimental ulcerative colitis induced by trinitrobenzenosulfonic acid (TNBS). Colonic damage was evaluated macroscopically and biochemically through its evaluation of glutathione content and its myeloperoxidase (MPO) and alkaline phosphatase activities. Additional in vitro experiments were performed in order to test the antioxidant activity by inhibition of induced lipid peroxidation in the rat brain membrane. Phytochemical analysis was performed by HPLC using authentic standards. The administration of plant extract (5 and 50 mgkg(-1)) significantly attenuated the colonic damage induced by TNBS as evidenced both macroscopically and biochemically. This beneficial effect can be associated with an improvement in the colonic oxidative status, since plant extract prevented glutathione depletion, inhibited lipid peroxidation and reduced MPO activity. Caffeic acid, p-coumaric acid, aromadendrin-4-O-methyl ether, 3-prenyl-p-coumaric acid, 3,5-diprenyl-p-coumaric acid and baccharin were detected in the plant extract.

Selenium and Mercury in the Brazilian Amazon: Opposing Influences on Age-Related Cataracts

BACKGROUND: Age-related cataracts (ARCs) are an important cause of blindness in developing countries. Although antioxidants may be part of the body's defense to prevent ARC, environmental contaminants may contribute to cataractogenesis. In fish-eating populations of the lower Tapajos region, elevated exposure to mercury (Hg) has been reported, and blood levels of selenium (Se) range from normal to very high (> 1,000 mu g/L). OBJECTIVES: We examined ARCs in relation to these elements among adults (>= 40 years of age) from 12 riverside communities. METHODS: Participants (n = 211) provided blood samples and underwent an extensive ocular examination. Inductively coupled plasma mass spectrometry was used to assess Hg and Se in blood and plasma. RESULTS: One-third (n = 69; 32.7%) of the participants had ARC. Lower plasma Se (P-Se; < 25th percentile, 110 mu g/L) and higher blood Hg (B-Hg; >= 25th percentile, 25 mu g/L) were associated with a higher prevalence odds ratio (POR) of ARC [adjusted POR (95% confidence interval), 2.69 (1.11-6.56) and 4.45 (1.43-13.83), respectively]. Among participants with high P-Se, we observed a positive but nonsignificant association with high B-Hg exposure, whereas among those with low B-Hg, we observed no association for P-Se. However, compared with the optimum situation (high P-Se, low B-Hg), the POR for those with low P-Se and high B-Hg was 16.4 (3.0-87.9). This finding suggests a synergistic effect. CONCLUSION: Our results suggest that persons in this population with elevated Hg, the cataractogenic effects of Hg may be offset by Se. Because of the relatively small sample size and possible confounding by other dietary nutrients, additional studies with sufficient power to assess multiple nutrient and toxic interactions are required to confirm these findings.

Deep sequencing of New World screw-worm transcripts to discover genes involved in insecticide resistance

Background: The New World screw-worm (NWS), Cochliomyia hominivorax, is one of the most important myiasis-causing flies, causing severe losses to the livestock industry. In its current geographical distribution, this species has been controlled by the application of insecticides, mainly organophosphate (OP) compounds, but a number of lineages have been identified that are resistant to such chemicals. Despite its economic importance, only limited genetic information is available for the NWS. Here, as a part of an effort to characterize the C. hominivorax genome and identify putative genes involved in insecticide resistance, we sampled its transcriptome by deep sequencing of polyadenylated transcripts using the 454 sequencing technology. Results: Deep sequencing on the 454 platform of three normalized libraries (larval, adult male and adult female) generated a total of 548,940 reads. Eighteen candidate genes coding for three metabolic detoxification enzyme families, cytochrome P450 monooxygenases, glutathione S transferases and carboxyl/cholinesterases were selected and gene expression levels were measured using quantitative real-time polymerase chain reaction (qRT-PCR). Of the investigated candidates, only one gene was expressed differently between control and resistant larvae with, at least, a 10-fold down-regulation in the resistant larvae. The presence of mutations in the acetylcholinesterase (target site) and carboxylesterase E3 genes was investigated and all of the resistant flies presented E3 mutations previously associated with insecticide resistance. Conclusions: Here, we provided the largest database of NWS expressed sequence tags that is an important resource, not only for further studies on the molecular basis of the OP resistance in NWS fly, but also for functional and comparative studies among Calliphoridae flies. Among our candidates, only one gene was found differentially expressed in resistant individuals, and its role on insecticide resistance should be further investigated. Furthermore, the absence of mutations in the OP target site and the high frequency of mutant carboxylesterase E3 indicate that metabolic resistance mechanisms have evolved predominantly in this species.

Cross-Talk Between Mitochondria and NADPH Oxidase: Effects of Mild Mitochondrial Dysfunction on Angiotensin II-Mediated Increase in Nox Isoform Expression and Activity in Vascular Smooth Muscle Cells

Mitochondria and NADPH oxidase activation are concomitantly involved in pathogenesis of many vascular diseases. However, possible cross-talk between those ROS-generating systems is unclear. We induced mild mitochondrial dysfunction due to mitochondrial DNA damage after 24 h incubation of rabbit aortic smooth muscle (VSMC) with 250 ng/mL ethidium bromide (EtBr). VSMC remained viable and had 29% less oxygen consumption, 16% greater baseline hydrogen peroxide, and unchanged glutathione levels. Serum-stimulated proliferation was unaltered at 24 h. Although PCR amplification of several mtDNA sequences was preserved, D-Loop mtDNA region showed distinct amplification of shorter products after EtBr. Such evidence for DNA damage was further enhanced after angiotensin-II (AngII) incubation. Remarkably, the normally observed increase in VSMC membrane fraction NADPH oxidase activity after AngII was completely abrogated after EtBr, together with failure to upregulate Nox1 mRNA expression. Conversely, basal Nox4 mRNA expression increased 1.6-fold, while being unresponsive to AngII. Similar loss in AngII redox response occurred after 24 h antimycin-A incubation. Enhanced Nox4 expression was unassociated with endoplasmic reticulum stress markers. Protein disulfide isomerase, an NADPH oxidase regulator, exhibited increased expression and inverted pattern of migration to membrane fraction after EtBr. These results unravel functionally relevant cross-talk between mitochondria and NADPH oxidase, which markedly affects redox responses to AngII. Antioxid Redox Signal 11, 1265-1278.

Hypervalent organochalcogenanes as inhibitors of protein tyrosine phosphatases

A series of organochalcogenanes was synthesized and evaluated as protein tyrosine phosphatases (PTPs) inhibitors. The results indicate that organochalcogenanes inactivate the PTPs in a time- and concentration-dependent fashion, most likely through covalent modification of the active site sulfur-moiety by the chalcogen atom. Consequently, organochalcogenanes represent a new class of mechanism-based probes to modulate the PTP-mediated cellular processes.

Continuous monitoring of ascorbate transport through neuroblastoma cells with a ruthenium oxide hexacyanoferrate modified microelectrode

The uptake of ascorbate by neuroblastoma cells using a ruthenium oxide hexacyanoferrate (RuOHCF)-modified carbon fiber disc (CFD) microelectrode (r = 14.5 mu m) was investigated. By use of the proposed electrochemical sensor the amperometric determination of ascorbate was performed at 0.0 V in minimum essential medium (MEM, pH = 7.2) with a limit of detection of 25 mu mol L(-1). Under the optimum experimental conditions, no interference from MEM constituents and reduced glutathione (used to prevent the oxidation of ascorbate during the experiments) was noticed. The stability of the RuOHCF-modified electrode response was studied by measuring the sensitivity over an extended period of time (120 h), a decrease of around 10% being noticed at the end of the experiment. The rate of ascorbate uptake by control human neuroblastoma SH-SY5Y cells, and cells transfected with wild-type Cu,Zn-superoxide dismutase (SOD WT) or with a mutant typical of familial amyotrophic lateral sclerosis (SOD G93A), was in agreement with the level of oxidative stress in these cells. The usefulness of the RuOHCF-modified microelectrode for in vivo monitoring of ascorbate inside neuroblastoma cells was also demonstrated.

Fatty acids decrease catalase activity in human leukaemia cell lines

Fatty acid (FA) may disturb the redox state of the cells not only by an increase in reactive oxygen species (ROS) generation but also due to a reduction in antioxidant enzyme activities. The effect of various FAs (palmitic, stearic, oleic, linoleic, gamma-linolenic and eicosapentaenoic acids (EPAs)) on Jurkat and Raji cells, (human T and B leukaemic cell lines was investigated). The following measurements were carried out: FA composition of the cells, cell proliferation and activities of catalase, glutathione peroxidase (GPx) and superoxide dismutase (SOD). The protective effect of alpha-tocopherol on cell death was also investigated. Each cell line presented a specific FA composition. All the tested ENS reduced catalase activity. The toxic effect of FA was abolished by the pre-incubation with physiological concentrations of alpha-tocopherol. The findings support the proposition that the increase in oxidative stress induced by FA partially occurs due to a reduction in catalase activity. In spite of the decrease in the enzyme activity, catalase protein and mRNA levels were not changed, suggesting a post-translational regulation. Copyright (C) 2007 John Wiley & Sons, Ltd.

Exercise training and caloric restriction prevent reduction in cardiac Ca(2+)-handling protein profile in obese rats

Previous studies show that exercise training and caloric restriction improve cardiac function in obesity. However, the molecular mechanisms underlying this effect on cardiac function remain unknown. Thus, we studied the effect of exercise training and/or caloric restriction on cardiac function and Ca(2+) handling protein expression in obese rats. To accomplish this goal, male rats fed with a high-fat and sucrose diet for 25 weeks were randomly assigned into 4 groups: high-fat and sucrose diet, high-fat and sucrose diet and exercise training, caloric restriction, and exercise training and caloric restriction. An additional lean group was studied. The study was conducted for 10 weeks. Cardiac function was evaluated by echocardiography and Ca(2+) handling protein expression by Western blotting. Our results showed that visceral fat mass, circulating leptin, epinephrine, and norepinephrine levels were higher in rats on the high-fat and sucrose diet compared with the lean rats. Cardiac nitrate levels, reduced/oxidized glutathione, left ventricular fractional shortening, and protein expression of phosphorylated Ser(2808)-ryanodine receptor and Thr(17-)phospholamban were lower in rats on the high-fat and sucrose diet compared with lean rats. Exercise training and/or caloric restriction prevented increases in visceral fat mass, circulating leptin, epinephrine, and norepinephrine levels and prevented reduction in cardiac nitrate levels and reduced: oxidized glutathione ratio. Exercise training and/or caloric restriction prevented reduction in left ventricular fractional shortening and in phosphorylation of the Ser(2808)-ryanodine receptor and Thr(17)-phospholamban. These findings show that exercise training and/or caloric restriction prevent cardiac dysfunction in high-fat and sucrose diet rats, which seems to be attributed to decreased circulating neurohormone levels. In addition, this nonpharmacological paradigm prevents a reduction in the Ser(2808)-ryanodine receptor and Thr(17-)phospholamban phosphorylation and redox status. (Hypertension. 2010;56:629-635.)

Aerobic exercise training improves Ca(2+) handling and redox status of skeletal muscle in mice

Exercise training is known to promote relevant changes in the properties of skeletal muscle contractility toward powerful fibers. However, there are few studies showing the effect of a well-established exercise training protocol on Ca(2+) handling and redox status in skeletal muscles with different fiber-type compositions. We have previously standardized a valid and reliable protocol to improve endurance exercise capacity in mice based on maximal lactate steady-state workload (MLSSw). The aim of this study was to investigate the effect of exercise training, performed at MLSSw, on the skeletal muscle Ca(2+) handling-related protein levels and cellular redox status in soleus and plantaris. Male C57BL/6J mice performed treadmill training at MLSSw over a period of eight weeks. Muscle fiber-typing was determined by myosin ATPase histochemistry, citrate synthase activity by spectrophotometric assay, Ca(2+) handling-related protein levels by Western blot and reduced to oxidized glutathione ratio (GSH:GSSG) by high-performance liquid chromatography. Trained mice displayed higher running performance and citrate synthase activity compared with untrained mice. Improved running performance in trained mice was paralleled by fast-to-slow fiber-type shift and increased capillary density in both plantaris and soleus. Exercise training increased dihydropyridine receptor (DHPR) alpha 2 subunit, ryanodine receptor and Na(+)/Ca(2+) exchanger levels in plantaris and soleus. Moreover, exercise training elevated DHPR beta 1 subunit and sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) 1 levels in plantaris and SERCA2 levels in soleus of trained mice. Skeletal muscle GSH content and GSH:GSSG ratio was increased in plantaris and soleus of trained mice. Taken together, our findings indicate that MLSSw exercise-induced better running performance is, in part, due to increased levels of proteins involved in skeletal muscle Ca(2+) handling, whereas this response is partially dependent on specificity of skeletal muscle fiber-type composition. Finally, we demonstrated an augmented cellular redox status and GSH antioxidant capacity in trained mice.

Intracellular mechanisms of specific beta-adrenoceptor antagonists involved in improved cardiac function and survival in a genetic model of heart failure

beta-blockers, as class, improve cardiac function and survival in heart failure (HF). However, the molecular mechanisms underlying these beneficial effects remain elusive. In the present study, metoprolol and carvedilol were used in doses that display comparable heart rate reduction to assess their beneficial effects in a genetic model of sympathetic hyperactivity-induced HF (alpha(2A)/alpha(2C)-ARKO mice). Five month-old HF mice were randomly assigned to receive either saline, metoprolol or carvedilol for 8 weeks and age-matched wild-type mice (WT) were used as controls. HF mice displayed baseline tachycardia, systolic dysfunction evaluated by echocardiography, 50% mortality rate, increased cardiac myocyte width (50%) and ventricular fibrosis (3-fold) compared with WT. All these responses were significantly improved by both treatments. Cardiomyocytes from HF mice showed reduced peak [Ca(2+)](i) transient (13%) using confocal microscopy imaging. Interestingly, while metoprolol improved [Ca(2+)](i) transient, carvedilol had no effect on peak [Ca(2+)](i) transient but also increased [Ca(2+)] transient decay dynamics. We then examined the influence of carvedilol in cardiac oxidative stress as an alternative target to explain its beneficial effects. Indeed, HF mice showed 10-fold decrease in cardiac reduced/oxidized glutathione ratio compared with WT, which was significantly improved only by carvedilol treatment. Taken together, we provide direct evidence that the beneficial effects of metoprolol were mainly associated with improved cardiac Ca(2+) transients and the net balance of cardiac Ca(2+) handling proteins while carvedilol preferentially improved cardiac redox state. (C) 2008 Elsevier Inc. All rights reserved.

Possible Relationship Between Performance and Oxidative Stress in Endurance Horses

The purpose of this study was to evaluate oxidative stress, antioxidant biomarkers, and performance during a multiday 210-km endurance race. Nine endurance athlete horses participated in this study. Samples were always taken at the same times of day, before the beginning of the race and after every day of competition. Analytic measurements included glutathione reductase (GR) and catalase activity, thiobarbituric acid-reactive substances (TBARs), and reactive carbonylated derivatives. Competition intensity was low, with an average speed of 12.56 +/- 0.9 km/h. Four horses were unable to finish the race because of metabolic problems or fatigue. GR activity increased progressively (P < .001) throughout the competition, and TBARs showed a significant rise compared with baseline values (P < .01) but remained at the same levels throughout the 3 days of competition. Catalase and reactive carbonylated derivatives did not show any significant alterations in any time period. The best performance was obtained from horses who demonstrated higher GR capacity and/or lower TBAR concentration. In conclusion, redox. status seems to modulate horses` performance in endurance races, but further Studies are needed to better determine the adequate oxidant/antioxidant ratio to acquire optimal performance.

Evaluation of children nasal geometry, employing accoustic rhinometry

The area above the nasal cavity plays a role in respiratory physiology. Aim: To analyze, during a period of growth, a possible change in the minimum cross sectional area (MCA) and nasal volume of the anterior nasal cavity. Materials and Methods: We evaluated 29 children (14 boys and 15 girls) with a mean age of 7.81 years at first examination (M1) and 11.27 years in the second examination (M2), without symptoms of nasal obstruction. The interval between examinations was 36-48 months. Children were subjected to the examination of acoustic rhinometry in which we recorded the minimum cross-sectional areas, volumes and their correlations with gender. Study design: Cohort. Results: The mean cross-sectional area of the nasal cavity of MCA for girls was 0.30 +/- 0.09 cm2 (M1) and 0.30 +/- 0.14 cm2 (M2), while for boys was 0.24 +/- 0.12 cm2 (M1) and 0.32 +/- 0.10 cm2 (M2). The mean values of the total volumes found for the whole sample were 2.17 +/- 0.23 cm3 (MCA1-M1), 2.56 +/- 0.27 cm3 (MCA1-M2), 4.24 +/- 1.17 cm3 (MCA2-M2) and 4.63 +/- 1.10 cm3 (MCA2-M2). Conclusion: There was no significant change in the minimum cross sectional area of the anterior nasal cavity. There was no significant difference between genders for both MCA and for the volume. There was a significant increase in MCA1.

Oxidative stress biomarkers of exposure in the blood of cichlid species from a metal-contaminated river

The oxidative stress biomarkers of exposure, such as reduced glutathione (GSH), activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and the levels of lipid peroxidation (LPO), were measured in the blood of three cichlid fish (Oreochromis niloticus, Tilapia rendalli, and Geophagus brasiliensis) taken during two seasons from two sites, unpolluted and polluted by industrial effluents, to evaluate the effectiveness of these biomarkers in assessing the impact of water contamination. The LPO levels in the blood were higher in fish from the metal-contaminated site and the chronic exposure led to significant changes in GPx, CAT, and SOD activities in all three cichlid species. The considerable variation of responses in these cichlids to water contamination evidenced differences in sensitivity to the metal contamination and/or in the potential to respond to it highlighting the importance of using a set of related biomarkers to assess the impact of water contamination. (C) 2007 Elsevier Inc. All rights reserved.