Plasmodium vivax apical membrane antigen-1: comparative recognition of different domains by antibodies induced during natural human infection

The Apical Membrane Antigen-1 (AMA-1) of Plasmodium sp. has been suggested as a vaccine candidate against malaria. This protein seems to be involved in merozoite invasion and its extra-cellular portion contains three distinct domains: DI, DII, and DIII. Previously, we described that Plasmodium vivax AMA-1 (PvAMA-1) ectodomain is highly immunogenic in natural human infections. Here, we expressed each domain, separately or in combination (DI-II or DII-III), as bacterial recombinant proteins to map immunodominant epitopes within the PvAMA-1 ectodomain. IgG recognition was assessed by ELISA using sera of P. vivax-infected individuals collected from endemic regions of Brazil or antibodies raised in immunized mice. The frequencies of responders to recombinant proteins containing the DII were higher than the others and similar to the ones observed against the PvAMA-1 ectodomain. Moreover, ELISA inhibition assays using the PvAMA-1 ectodomain as substrate revealed the presence of many common epitopes within DI-II that are recognized by human immune antibodies. Finally, immunization of mice with the PvAMA-1 ectodomain induced high levels of antibodies predominantly to DI-II. Together, our results indicate that DII is particularly immunogenic during natural human infections, thus indicating that this region could be used as part of an experimental sub-unit vaccine to prevent vivax malaria. (C) 2008 Elsevier Masson SAS. All rights reserved.

Determination of Vecuronium Bromide in Pharmaceuticals: Development, Validation and Comparative Study of HPLC and CZE Analytical Methods

Vecuronium bromide is a neuromuscular blocking agent used for anesthesia to induce skeletal muscle relaxation. HPLC and CZE analytical methods were developed and validated for the quantitative determination of vecuronium bromide. The HPLC method was achieved on an amino column (Luna 150 x 4.6 mm, 5 mu m) using UV detection at 205 nm. The mobile phase was composed of acetonitrile:water containing 25.0 mmol L(-1) of sodium phosphate monobasic (50:50 v/v), pH 4.6 and flow rate of 1.0 mL min(-1). The CZE method was achieved on an uncoated fused-silica capillary (40.0 cm total length, 31.5 cm effective length and 50 mu m i.d.) using indirect UV detection at 230 nm. The electrolyte comprised 1.0 mmol L(-1) of quinine sulfate dihydrate at pH 3.3 and 8.0% of acetonitrile. The results were used to compare both techniques. No significant differences were observed (p > 0.05).

Care during freeze-drying of bovine pericardium tissue to be used as a biomaterial: A comparative study

Bovine pericardium (BP) tissue is widely used in the manufacture of bioprosthetics. The effects of freeze-drying on the BP tissue have been studied by some researchers in order to decrease their cytotoxicity due to preservation in formaldehyde solution, and to increase the lifetime of the product in storage. This study was undertaken in order to study the effect of freeze-drying in the structure of BP. To perform this study BP samples were freeze-dried in two different types of freeze-dryers available in our laboratory: a laboratory freeze-dryer, in which it was not possible to control parameters and a pilot freeze-dryer, wherein all parameters during freezing and drying were controlled. After freeze-drying processes, samples were analyzed by SEM, Raman spectroscopy, tensile strength, water uptake tests and TEM. In summary, it has been demonstrated that damages occur in collagen fibers by the loss of bulk water of collagen structure implicating in a drastic decreasing of BP mechanical properties due to its structural alterations. Moreover, it was proven that the collagen fibrils suffered breakage at some points, which can be attributed to the uncontrolled parameters during drying. (C) 2011 Elsevier Inc. All rights reserved.

Determination of chlorpheniramine in human plasma by HPLC-ESI-MS/MS: application to a dexchlorpheniramine comparative bioavailability study

In the present study a fast, sensitive and robust validated method to quantify chlorpheniramine in human plasma using brompheniramine as internal standard (IS) is described. The analyte and the IS were extracted from plasma by LLE (diethyl ether-dichloromethane, 80:20, v/v) and analyzed by HPLC-ESI-MS/MS. Chromatographic separation was performed using a gradient of methanol from 35 to 90% with 2.5 mm NH(4)OH on a Gemini Phenomenex C(8) 5 mu m column (50 x 4.6 mm i.d.) in 5.0 min/run. The method fitted to a linear calibration curve (0.05-10 ng/mL, R > 0.9991). The precision (%CV) and accuracy ranged, respectively: intra-batch from 1.5 to 6.8% and 99.1 to 106.6%, and inter-batch from 2.4 to 9.0%, and 99.9 to 103.1%. The validated bioanalytical procedure was used to assess the comparative bioavailability in healthy volunteers of two dexchlorpheniramine 2.0 mg tablet formulations (test dexchlorpheniramine, Eurofarma, and reference Celestamine (R), Schering-Plough). The study was conducted using an open, randomized, two-period crossover design with a 2 week washout interval. Since the 90% confidence interval for C(max) and AUC ratios were all within the 80-125% interval proposed by ANVISA and FDA, it was concluded that test and reference formulations are bioequivalent concerning the rate and the extent of absorption. Copyright (C) 2009 John Wiley & Sons, Ltd.

WHO comparative evaluation of serologic assays for Chagas disease

Evaluation of commercially available test kits for Chagas disease for use in blood bank screening is difficult due to a lack of large and well-characterized specimen panels. This study presents a collaborative effort of Latin American blood centers and the World Health Organization (WHO) to establish such a panel. A total of 437 specimens, from 10 countries were collected and sent to the WHO Collaborating Center in Sao Paulo and used to evaluate 19 screening assays during 2001 through 2005. Specimens were assigned a positive or negative status based on concordant results in at least three of the four confirmatory assays (indirect immunofluorescence, Western blot, radioimmunoprecipitation assay, and recombinant immunoblot). Of the 437 specimens, 168 (39%) were characterized as positive, 262 (61%) were characterized as negative, and 7 (2%) were judged inconclusive and excluded from the analysis. Sensitivity and specificity varied considerably: 88 to 100 and 60 to 100 percent, respectively. Overall, enzyme immunoassays (EIAs) performed better than the other screening assays. Four EIAs had both parameters higher than 99 percent. Of the four confirmatory assays, only the RIPA gave a 100 percent agreement with the final serologic status of the specimens. The sensitivities and specificities of at least four of the commercially available EIAs for Chagas disease are probably high enough to justify their use for single-assay screening of blood donations. Our data suggest that the majority of commercially available indirect hemagglutination assays should not be used for blood donor screening and that the RIPA could be considered a gold standard for evaluating the performance of other assays.

Comparative analysis of the gas-phase reactions of cylindrospermopsin and the difference in the alkali metal cation mobility

Cylindrospermopsin (CYN) belongs to a group of toxins produced by several strains of freshwater cyanobacteria. It is a compact zwitterionic molecule composed of a uracil section and a tricyclic guanidinium portion with a primarily hepatotoxic effect. Using low multi-stage and high-resolution mass spectrometry, the gas-phase reactions of this toxin have been investigated. Our data show that collision-induced dissociation (CID) spectra of CYN are dominated by neutral losses, and three major initial fragmentation pathways are clearly distinguishable. Interestingly, comparative analysis of protonated and cationizated molecules showed a significant difference in the balance of the SO(3) and terminal ring elimination. These data indicate that the differential ion mobility of H(+), Li(+), Na(+) and K(+) leads to different fragmentation pathways, giving rise to mass spectra with different profiles. Copyright (C) 2008 John Wiley & Sons, Ltd.

Increase of core temperature induced by corticotropin-releasing factor and urocortin: A comparative study

This study compared the ability of CRF and UCN1 to induce a thermoregulatory response when centrally injected into rats. The effects of antipyretic drugs and CRF receptor antagonists (CRF(1) and CRF(2)) on the temperature (T) changes induced by these peptides were also investigated. Rectal (rT) and tail skin (T(sk)) temperatures were measured with a thermistor probe while body (bT) temperature was measured with a battery-operated biotelemetry transmitter in male Wistar rats (200 g) every 30 min over a period of 6 h, after intracerebroventricular (i.c.v.) injection of 1 nmol of either CRF or UCN1. Rats were pre-treated with indomethacin (2 mg kg(-1), i.p.) or celecoxib (5 mg kg(-1), p.o.), dexamethasone (0.5 mg kg(-1), s.c.), astressin (a CRF(1)/CRF(2) antagonist, 7 nmol, icy.) or antalarmin (a CRF(1) antagonist, 20 mg kg 1, i.p.). The increase in body temperature induced by CRF was accompanied by a reduction in T(sk) while the response induced by UCN1 was accompanied by an elevation in T(sk). Indomethacin or celecoxib did not change the increases in rT caused by either CRF or UCN1. Although dexamethasone attenuated the increase in rectal temperature in response to CRF, dexamethasone did not modify the response induced by UCN1. Astressin blocked the UCN1-induced hyperthermia and reduced CRF-induced fever. Antalarmin did not modify the hyperthermia in response to UCN1, but reduced the fever evoked by CRF. This study demonstrated that CRF by acting on the CRF(1) receptor induces a prostaglandin-independent fever which seems to depend, at least in part, on the synthesis of other mediators while UCN1 acts on the CRF(2) receptor, promoting a hyperthermic response which seems to be independent on synthesis/release of any mediator. (C) 2010 Elsevier B.V. All rights reserved.

Comparative effects of lantadene A and its reduced metabolite on mitochondrial bioenergetics

Lantana (Lantana camara Linn.) is a noxious weed to which certain medicinal properties have been attributed, but its ingestion has been reported to be highly toxic to animals and humans, especially in the liver. The main hepatotoxin in lantana leaves is believed to be the pentacyclic triterpenoid lantadene A (LA), but the precise mechanism by which it induces hepatotoxicity has not yet been established. This work addressed the action of LA and its reduced derivative (RLA) on mitochondrial bioenergetics. At the concentration range tested (5-25 mu M), RLA stimulated state-4 respiration, inhibited state-3 respiration, circumvented oligomycin-inhibited state-3 respiration, dissipated membrane potential and depleted ATP in a concentration-dependent manner. However. LA did not stimulate state-4 respiration, nor did it affect the other mitochondrial parameters to the extent of its reduced derivative. The lantadenes didn`t inhibit the CCCP-uncoupled respiration but increased the ATPase activity of intact coupled mitochondria. The ATPase activity of intact uncoupled or disrupted mitochondria was not affected by the compounds. We propose, therefore, that RLA acts as a mitochondrial uncoupler of oxidative phosphorylation, a property that arises from the biotransformation (reduction) of LA, and LA acts in other mitochondrial membrane components rather than the ATP synthase affecting the mitochondrial bioenergetics. Such effects may account for the well-documented hepatoxicity of lantana. (C) 2010 Elsevier Ltd. All rights reserved.

Comparative study of laser and LED systems of low intensity applied to tendon healing

The aim of this study was to compare the effects of Low-intensity Laser Therapy (LILT) and Light Emitting Diode Therapy (LEDT) of low intensity on the treatment of lesioned Achilles tendon of rats. The experimental model consisted of a partial mechanical lesion on the right Achilles tendon deep portion of 90 rats. One hour after the lesion, the injured animals received applications of laser/LED (685, 830/630, 880 nm), and the same procedure was repeated at 24-h intervals, for 10 days. The healing process and deposition of collagen were evaluated based on a polarization microscopy analysis of the alignment and organization of collagen bundles, through the birefringence (optical retardation-OR). The results showed a real efficiency of treatments based on LEDT and confirmed that LILT seems to be effective on healing process. Although absence of coherence of LED light, tendon healing treatment with this feature was satisfactory and can certainly replace treatments based on laser light applications. Applications of infrared laser at 830 nm and LED 880 nm were more efficient when the aim is a good organization, aggregation, and alignment of the collagen bundles on tendon healing. However, more research is needed for a safety and more efficient determination of a protocol with LED.

Bioactive Chemical Constituents and Comparative Antimicrobial Activity of Callus Culture and Adult Plant Extracts from Alternanthera tenella

Crude extracts of a callus culture (two culture media) and adult plants (two collections) from Alternanthera tenella Colla (Amaranthaceae) were evaluated for their antibacterial and antifungal activity, in order to investigate the maintenance of antimicrobial activity of the extracts obtained from plants in vivo and in vitro. The antibacterial and antifungal activity was determined against thirty strains of microorganisms including Gram-positive and Gram-negative bacteria, yeasts and dermatophytes. Ethanolic and hexanic extracts of adult plants collected during the same period of the years 1997 and 2002 [Ribeirao Preto (SP), collections 1 and 2] and obtained from plant cell callus culture in two different hormonal media (AtT43 and AtT11) inhibited the growth of bacteria, yeasts and dermatophytes with inhibition halos between 6 and 20 mm. For the crude extracts of adult plants bioassay-guided fractionation, purification, and isolation were performed by chromatographic methods, and the structures of the isolated compounds were established by analysis of chemical and spectral evidences (UV, IR, NMR and ES-MS). Steroids, saponins and flavonoids (aglycones and C-glycosides) were isolated. The minimum inhibitory concentration (MIC) of the isolated compounds varied from 50 to 500 mu g/mL.

A Comparative Analysis of the Changes During Evaporation of Three Different Commercial Emulsion of Unknown Composition

Optical microscope and centrifugation were used to observe the structure change during evaporation of three different commercial emulsions of unknown composition. The degree of evaporation under an infrared lamp at 70 degrees C was determined from the changed weight of a microscope slide with the emulsion on a defined area and thickness. The results revealed information as to which kind of structure would appear after evaporation.

Concepts and tools for comprehensive sustainability assessments for tourism destinations: a comparative review

This paper reviews a wide range of tools for comprehensive sustainability assessments at whole tourism destinations, covering socio-cultural, economic and environmental issues. It considers their strengths, weaknesses and site specific applicability. It is intended to facilitate their selection (and combination where necessary). Tools covered include Sustainability Indicators, Environmental Impact Assessment, Life Cycle Assessment, Environmental Audits, Ecological Footprints, Multi-Criteria Analysis and Adaptive Environmental Assessment. Guidelines for evaluating their suitability for specific sites and situations are given as well as examples of their use.

Recreational fishing and fishing policies in the Netherlands and Australia: A comparative review

This article compares fisheries management, environmental problems and policies of the Netherlands and Australia. From this comparison lessons can be learned for countries that experience economic growth and on increase of leisure activity. In both countries, conflicts between the user groups, e.g. commercial and recreational fishers, are identified and the ways in which policymakers deal with these problems are outlined. Often suggested tools to address these problems are decision-making procedures based on a holistic framework in which economic, sociocultural, political/institutional, ecological aspects are included in the decision framework. Recreational fishing is today often the dominant factor in the resolution of these matters because of the relative economic, social and political power of recreational fishers as a group.

Comparative public support for conserving reptile species is high: Australian evidence and its implications

This paper investigates factors influencing the public’s support for conservation of tropical reptile species in a focal group drawing on Australian data and an experiment involving a sample of the Australian public. The influences of the likeability of the species, their degree of endangerment, ethical considerations as well as knowledge are examined and found to be important. Likeability is found to be much less important than the existing literature suggests. This is highlighted by comparing the likeability of the focal group of reptiles with that for a group of birds and a group of mammals with differences in willingness to pay for their conservation.