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Like many other organic ligands, amine-based complexing agents in analytical chemistry have demonstrated substantial improvements in sensitivity and selectivity in determining metals by flame-atomic absorption spectrometry (FAAS) and electrothermal atomisation atomic absorption spectrometry (ETAAS). Amines represent a particular case for diverse potential complexing agents owing to the lone pair electrons in the nitrogen atom being capable of forming dative covalent bonds. Amines can analytically generate useful pH-dependent green switchable solvents. In this context, this work aims to critically review the diverse uses of amines in the FAAS/ETAAS fields in a comprehensive manner by mainly focusing on their effects on the atomisation processes, their behaviour as complexing agents and their possible direct and indirect determination by the AAS techniques. Various theoretical topics related to the solvent extraction processes involving amines also enhance the usefulness of this kind of compound for the AAS techniques. Further, extrapolating their usefulness in combination with other analytical techniques is straightforward. [ABSTRACT FROM AUTHOR]

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This study evaluated anatomic and physiological modifications in Panicum aquaticum plants related to cadmium (Cd) tolerance. The plants were cultivated in a nutritive solution, with addition of increasing concentration of Cd. The following parameters were analyzed: absorption, translocation, concentration and Cd accumulation, growth, gas exchanges, activity of the antioxidant system, and anatomy of roots and leaves. Absorption and Cd concentration increased throughout the treatments, while accumulation and Cd translocation did not vary, due to maintenance of the biomass. Gas exchanges were not affected by Cd. Specific foliar area increased in the presence of the metal, and might be related to the reduction in leaf blade thickness and chlorophyllic parenchyma. Modifications in stomatal characteristics did not negatively affect gas exchanges. An increase in the exodermis and endodermis thickness restricted Cd translocation to the aerial part, avoiding damages to the photosynthetic system. Activity of the ascorbate peroxidase and catalase in the root contributed to a reduction in the metal toxicity. P. aquaticum presented an efficient capacity for Cd absorption, but restricted translocation. Cd accumulation was higher in the roots. Anatomic and physiological responses show a tolerance of the species to Cd in the evaluated concentrations. [ABSTRACT FROM AUTHOR]

The polymorphic merozoite surface protein-2 (MSP-2) of Plasmodium falciparum is a major malaria-vaccine candidate. In the present study, PCR and hybridization with allelic-specific probes were used to type the Msp-2 gene from isolates from hypo-endemic Brazil (N = 113), meso-endemic Vietnam (N = 208) and holo-endemic Tanzania (N = 67). The typing methods were designed to group isolates into the dimorphic allelic families FC27 and IC1 and to detect possible between-family recombination events. The analysis was complemented by a comparison of 156 Msp-2 sequences from the GenBank database with 12 additional sequences obtained during the present study. Statistically significant differences were detected in pair-wise comparisons of the distribution of Msp-2 allelic types in Brazil and Vietnam, and in Brazil and Tanzania, but not in Vietnam and Tanzania. The extent of allelic diversity in the Msp-2 gene, as estimated by the total number of different alleles found in a given parasite population and the mean multiplicity of infections, clearly paralleled the levels of malaria endemicity in the study areas. However, no correlation between age and multiplicity of infections was found in the subjects. The patterns of Msp-2 diversity in Brazil appeared to be temporally stable, since no significant difference was observed in the distribution of Msp-2 allelic types among isolates collected, 10-13 years apart, in the same area of Rondônia. Despite the extensive sequence diversity found in Msp-2 alleles, especially in the central repetitive region of the molecule, several instances of identical or nearly identical alleles were found among isolates from different countries and regions, possibly as a result of extensive homoplasy. No recombinant allele was detected by molecular typing in any of the study sites, and the GenBank database included only 12 recombinant sequences (representing 7% of all reported Msp-2 sequences), all of them with an IC1-type 5' end and an FC27-type 3' end. A single, putative, crossover site was characterised for all recombinant alleles. Most of the allelic diversity observed was therefore attributable to variation in the repetitive region of the gene, instead of recombination between alleles of dimorphic families (as commonly found, for example, in the Msp-1 gene). The implications of these findings for studies on the genetic and antigenic diversity of malarial parasites are discussed. [ABSTRACT FROM AUTHOR]

Cobalt is an essential element, but its wide use in industry generates important environmental and biological problems. The present study explores theoretical and empirical models of a green process for cobalt {Co 2+ } bioaccumulation from aqueous solutions. Two Gram-positive Bacillus subtilis species, strains CECT 4522 and LMM (the latter a former laboratory isolate from wastewater samples, which was phylogenetically characterized for the present work), were selected among others as the best Co 2+ accumulation systems. Mathematical models representing kinetic and steady-state conditions for discrete and large amounts of bacterial biomass were expanded. In this way, it was possible to theoretically calculate the amount of Co 2+ retained on the outer cell wall layer and incorporated inside the cell at any time. Theoretical and empirical hyperbolic-type models were suitable to fit the experimental bioaccumulation data for discrete amounts of bacteria biomass. In addition, kinetic relationships between the amount of Co 2+ accumulated and the time before (or after) reaching steady state were established for large amounts of bacterial biomass. Other kinetic approaches were also satisfactorily tested. The two Gram-positive bacteria assayed are promising agents for developing heavy metal removal systems from industrial waste.

Two novel thoria (ThO2) nanoparticles-carbon paste electrodes were used to evaluate an anodic stripping voltammetric method for the direct determination of arsenite and total inorganic arsenic (arsenite plus arsenate) in water samples. The effect of Ag((I)), Cu((II)), Hg((II)), Sb((III)) and Se((IV)) ions on the electrochemical response of arsenic was assayed. The developed electroanalytical method offers a rapid procedure with improved analytical characteristics including good repeatability (3.4%) at low As((III)) concentrations, high selectivity, lower detection limit (0.1 μg L(-1)) and high sensitivity (0.54 μA μg(-1) L). The analytical capability of the optimized method was demonstrated by the determination of arsenic in certified reference materials (trace elements in natural water, trace elements in water and coal fly ash)., (Copyright © 2016 Elsevier B.V. All rights reserved.)

We have compared Duffy blood group genotype distribution, as determined by polymerase chain reaction with allele-specific primers, in 68 Plasmodium vivax-infected patients and 59 non-vivax malaria controls from Rondônia, Brazil. Homozygosity for the allele Fy, which abolishes Duffy antigen expression on erythrocytes, was observed in 12% non-vivax controls but in no P. vivax patient. However, no significant association was found between Fy heterozygosity and protection against P. vivax. The Fy x allele, which has recently been associated with very weak erythrocyte expression of Duffy antigen, was not found in local P. vivax patients.

Two polymerase chain reaction (PCR) protocols showed low sensitivity (36% and 53% for TB AMPLICOR and MPB64 nested PCR, respectively), when compared with classic microbiological methods (73% and 54% for Ziehl-Neelsen staining and culture, respectively), in the diagnosis of tuberculous meningitis in 91 patients in southeastern Brazil. Only three PCR-positive, microbiologically negative patients were found. Analysis of sequential cerebrospinal fluid samples by nested PCR detected Mycobacterium tuberculosis DNA up to 29 days after the introduction of antituberculosis chemotherapy.

Rationale and Objectives: Contrast media (CM)-induced renal vasoconstriction is an important factor in the pathogenesis of CM-induced nephrotoxicity. The effects of ionic, high-osmolar CM sodium/meglumine diatrizoate and nonionic, low-osmolar CM iohexol and iopamidol were studied in rabbit, dog, and pig renal arteries and compared with human tissue in an organ bath., Methods: Isometric contractions were induced by increasing concentrations of CM and high-osmolar glucose solution., Results: Contrast media and glucose elicited contractions in human renal arteries of 32% (diatrizoate), 20% (iohexol), 30% (iopamidol), and 22% (glucose). Rabbit and dog renal arteries demonstrated contractions of 30% and 46% (diatrizoate), 15% and 23% (iohexol), 15% and 26% (iopamidol), and 11% and 40% (glucose), respectively, of the control. There was a vasorelaxing effect of all CM tested on pig renal artery., Conclusions: Responses in rabbit and dog renal arteries were similar to those in human renal arteries and could serve as models for investigating CM-induced renal vasoconstriction.

Purpose: The purpose of this study was to investigate the association between temporomandibular joint (TMJ) pain and histological changes in TMJs with disc displacement., Method: Samples from capsules and posterior disc attachments from 27 TMJ pain patients who underwent surgery were compared with samples from seven asymptomatic persons., Results: On logistic regression analysis, retrodiscal tissues from the painful joints demonstrated a significantly higher density of fibroblasts, presence of narrowed and obliterated arterial lumens, and a significantly lower distribution of elastic fibers., Conclusion: The results indicate that there is a difference between painful and asymptomatic joints at the microscopic level.

The purpose of this autopsy study was to test the hypotheses that temporomandibular joint (TMJ) arthrosis is more common in women than in men, increases with age, and is more common in edentulous persons than in those with natural teeth. Two hundred forty-eight TMJs removed at autopsy from 224 fresh cadavers were investigated macroscopically with dissection or cryosectioning. Age was found to be a significant factor in prediction of TMJ arthrosis (p < 0.001) and of disk perforation (p < 0.05). No significant association was found between morphologic changes in the TMJ and the factor of sex for the whole group. Disk displacement and disk perforation were, however, more common in the joints of women than men in the group of persons 80 years of age or older (p < 0.05). There were significant associations (p < 0.001) between arthrosis, disk displacement, disk deformation, and disk perforation. There were no statistically significant differences in the prevalence of morphologic changes in the joints from persons with 10 or more natural teeth in each jaw compared with those from persons without natural teeth. The results of this study showed that TMJ arthrosis is more frequent in older than in younger persons. TMJ disk displacement generally appears necessary for the development of perforations. The findings of this study indicate that sex and dentition are not major factors for the development of TMJ pathosis in elderly individuals.

Numerous temporomandibular joint autopsy studies have been presented in the literature for the last two decades, but signs and symptoms of temporomandibular disorders before death were not available. To investigate the clinical significance of morphologic changes in the temporomandibular joint, 19 persons were clinically examined for signs and symptoms of temporomandibular disorders. The temporomandibular joints were subsequently analyzed macroscopically at autopsy and statistically associated with history and clinical findings. The average time between clinical examination and autopsy was 12 months. Signs and symptoms of temporomandibular disorders were not common findings for these persons. Morphologically, 31 of the 34 joints showed different forms of changes such as deviation in form, arthrosis, disk displacement, disk deformation, and adhesions. Crepitation showed a significant association with arthrosis. It was concluded that the association between pain and dysfunction and joint morphology is complex and gross morphologic alterations can be present in the absence of temporomandibular joint pain and dysfunction.

Comparisons among several temporomandibular joint autopsy studies indicate that the frequency of arthrosis and disk displacement is higher in elderly persons. The aim of this study was to investigate type, frequency, and location of morphologic changes in temporomandibular joint autopsy specimens divided into two groups according to age and to determine the differences between the two groups. For this purpose 68 temporomandibular joints were removed from 37 persons at autopsy. Group I (young) consisted of 36 specimens belonging to 19 persons with a mean age of 30 years (range, 16 to 39 years). Group II (elderly) consisted of 32 specimens from persons with a mean age of 68 years (range, 55 to 78 years). Significant differences between the two groups were observed with respect to several of the morphologic changes that were evaluated. The results of this study suggest that the frequency of morphologic changes such as deviation in form, arthrosis, perforations, disk displacement, disk deformation, and adhesions is higher in the temporomandibular joints of elderly persons.

The authors report the case of a 31 year-old male with right atrial myxoma whose clinical manifestations included: malaise, dizziness and dyspnea on great exertion. At physical examination, a tricuspid systolic and diastolic murmur of mean intensity was found. The chest radiography and the electrocardiogram signs were of right atrial and ventricular enlargement, and the diagnosis was made with the B-mode echocardiogram. The patient underwent surgical removal of the tumoral mass and diagnostic confirmation was made with the histopathologic study of the 75 x 50 x 40 mm piece. The patient obtained clinical, electrocardiographic and radiologic remission.