Kinetics and equilibrium study for the biosorption of lanthanum by Penicillium simplicissimum INCQS 40,211.

Lanthanum (La) is a light rare-earth element that plays an essential role in manufacturing technological products, clean technologies, medical products, electron cathodes, scintillators, fluorescent lamps, and fertilizers. This study is the first investigation of La3+ biosorption using inactive lyophilized biomass from Penicillium simplicissimum INCQS 40,211. The maximum sorption capacity (qmax) for P. simplicissimum was 7.81 mg g-1. La 3+ biosorption followed the Freundlich model, where the biosorption system possibly multilayer coverage of P. simplicissimum by lanthanum ions. The kinetic data for the adsorption process obeyed a pseudo-second-order (R 2 > 0.92), indicating chemical sorption. The results indicated that inactive lyophilized biomass from Penicillium simplicissimum INCQS 40211are an excellent candidate for removing light rare-earth elements from aquatic environments.

Toxicity of three rare earth elements, and their combinations to algae, microcrustaceans, and fungi.

Rare earth elements (REEs) are naturally distributed in the environment, and are increasingly being used in agriculture and high technology materials worldwide, thereby increasing anthropogenic contamination and environmental risks. There exists scarce and contradictory toxicity information about REEs; hence, more studies are required, especially on their mixtures. Thus, this study aimed to assess the toxicities of La3+, Nd3+, Sm3+, and the combinations of these elements (binary 1:1 and ternary 1:1:1), to organisms from different trophic levels: producers (the microalgae Chlorella vulgaris and Raphidocelis subcapitata), primary consumers (the microcrustaceans Daphnia similis and Artemia salina), and decomposers (the fungi Penicillium simplicissimum and Aspergillus japonicus). Ecotoxicological bioassays were performed, and toxic concentrations were determined. Thereafter, toxicities of single and mixture REEs were classified as slightly to highly toxic according to their toxic units. Finally, a concentration addition (CA) model was used to estimate how REEs interact upon combining. Nd3+ was the most toxic element for all organisms, especially D. similis (48 h LC50 9.41 mg.L-1), and was therefore classified as highly toxic. Sm3+ promoted cell agglomeration in Chlorella vulgaris and was the most toxic of the tested elements for this organism (72 h IC50 25.78 mg.L-1). The CA model revealed synergistic responses for most of the combinations, principally Nd3+ + Sm3+, which was the most toxic combination for the tested organisms. Both fungi were the most resistant organisms, and A. japonicus produced exudate and sclerotia, which help in the detoxification of chemicals. Owing not only to the fact that fungi displayed a higher resistance to REEs, but also due to the absence of regulations for REEs released from the agricultural or industrial sector, and the lack of methods to treat effluents or to dispose of technological items containing REEs, these organisms should be considered as a model for the biosorption or bioremediation of REEs. Finally, the toxic effects of REEs, particularly Nd3+, on the biota and human health should be the focus of future studies due to their increased use in technology.

The performance of a multi guard ring (MGR) diode for clinical electron beams dosimetry.

The dosimetric response of a multi guard ring structure (MGR) diode has been studied with clinical electron beam energies from 5 MeV to 15 MeV. The results showed that the MGR dose response is linear in the range of 5-320 cGy and presents reproducibility with variation coefficients less than 0.4%. The field output factors measured with the MGR agreed within 2% with those measured with an ionization chamber. This study evidences that this diode can be used for clinical electron beam dosimetry.

The influence of Ouabain on human dendritic cells maturation.

Although known as a Na,K-ATPase inhibitor, several other cellular and systemic actions have been ascribed to the steroid Ouabain (Oua). Particularly in the immune system, our group showed that Ouabain acts on decreasing lymphocyte proliferation, synergizing with glucocorticoids in spontaneous thymocyte apoptosis, and also lessening CD14 expression and blocking CD16 upregulation on human monocytes. However, Ouabain effects on dendritic cells (DCs) were not explored so far. Considering the peculiar plasticity and the importance of DCs in immune responses, the aim of our study was to investigate DC maturation under Ouabain influence. To generate immature DCs, human monocytes were cultured with IL-4 and GM-CSF (5 days). To investigate Ouabain role on DC activation, DCs were stimulated with TNF-α for 48 h in the presence or absence of Ouabain. TNF-induced CD83 expression and IL-12 production were abolished in DCs incubated with 100 nM Ouabain, though DC functional capacity concerning lymphocyte activation remained unaltered. Nevertheless, TNF-α-induced antigen capture downregulation, another maturation marker, occurred even in the presence of Ouabain. Besides, Ouabain increased HLA-DR and CD86 expression, whereas CD80 expression was maintained. Collectively, our results suggest that DCs respond to Ouabain maturating into a distinct category, possibly contributing to the balance between immunity and tolerance.

mCD14 expression in human monocytes is downregulated by ouabain via transactivation of epithelial growth factor receptor and activation of p38 mitogen-activated protein kinase.

BACKGROUND AND AIMS: The steroid ouabain is found in plasma and in many mammalian tissues, and is now considered as a hormone. In the immune system, ouabain regulates a number of lymphocyte functions, but little is known about its effects on monocyte function. Monocytes are important for adequate immune responses. The aim of this work was to analyze the effect of ouabain on mCD14 expression, a surface molecule involved in the response against Gram-negative bacteria and phagocytosis. METHODS: Human peripheral blood mononuclear cells obtained from healthy donors were separated by density gradient centrifugation. Monocytes were separated by adherence and treated for 24 h with 100 nM ouabain. mCD14, CD1a and P-p38 expression was analyzed by flow cytometry. Inhibitors of cell-signaling pathways, i.e. SB202190, reduced glutathione, rottlerin, tyrphostin A23, genistein, chelerythrine chloride, PD98059, PP1 and Ly 294002, were used concomitantly with ouabain to observe their effect on mCD14 expression. RESULTS: Ouabain induced a significant decrease in mCD14 expression. This feature was not related to receptor endocytosis or cell death. Furthermore, mCD14 downregulation did not reflect a shift in differentiation into dendritic cells because this hormone failed to induce CD1a expression. Amongst several inhibitors of cell-signaling pathways triggered by ouabain, only epidermal growth factor receptor (EGFR) and p38 mitogen-activated protein kinase (MAPK) inhibitors (tyrphostin A23 and SB202109) significantly reverted the effect of ouabain on mCD14 expression. Accordingly, the levels of P-p38 were increased on monocytes after ouabain treatment. However, incubation with epidermal growth factor did not alter mCD14 expression. CONCLUSION: These findings suggest that ouabain downregulates mCD14 expression on monocytes through EGFR transactivation and p38 MAPK activation.

Synthesis and antitumour activity of the Primin (2-methoxy-6-n-pentyl-1,4-benzoquinone) and analogues.

Cancer is a serious worldwide health threat, killing almost seven million people per year. Quinones are an important class of antitumour agents that are activated by tumour hypoxia. Primin (2-methoxy-6-n-pentyl-1,4-benzo-quinone), a naturally-occurring product obtained from Primula obconica (Primulaceae) has shown antimicrobial and antitumour properties. The synthesis of the Primin to obtain 3-, 5- or 6-alkyl substituted derivatives has been previously attempted seeking antitumour activity. The intermediate reaction products, 2-methoxy-hydroquinone-di-(2'-tetrahydro-pyranyl) ether and 2-methoxy-6-n-pentyl-hydroquinone-di-(2'-tetrahydropyranyl) ether were obtained and evaluated against sarcoma 180 (S-180) and Ehrlich carcinoma, as well as toxicity tests were performed. The antitumour activity tests showed that these intermediate compounds were able to inhibit S-180 sarcoma and Ehrlich carcinoma growth in mice. These results indicated that the tetrahydropyranyl protect group conserved the antitumour activity in comparison with quinone group, however, it exhibited a less toxic effect, with no characteristic of quinones. These results can suggest that compound 2-methoxy-6-n-pentyl-hydroquinone-di-(2'-tetrahydropyranyl) ether may act as a prodrug with some advantages in comparison with the Primin.

Modulation of multidrug resistance protein (MRP1/ABCC1) expression: a novel physiological role for ouabain.

Besides being a (Na(+),K(+))-ATPase inhibitor, high doses of the hormone ouabain have also been reported to modulate both the expression and activity of proteins belonging to the ATP binding cassette family of transporters, such as ABCC7 (CFTR), ABCB1 (P-glycoprotein), and ABCC1 (MRP1). Although these proteins are present in the kidney, only ABCB1 has a putative physiological role in this organ, secreting endobiotics and xenobiotics. In the present work, we studied the relationship between ouabain and ABCC1 expression and function, aiming to establish a physiological role for ouabain. It was observed that prolonged (24 h) but not short (30 min) incubation with 1 nmol/L or higher ouabain concentrations decreased the expression of ABCC1 protein and induced its mRNA expression. This decrease was rapidly reversible, reaching control levels after incubation of cells in ouabain-free medium for 3 h, denoting a hormonal action. Moreover, concentrations equal or higher than 100 nmol/L ouabain also induced impairment of ABCC1 activity, increasing the accumulation of carboxyfluorescein diacetate, an ABCC1 fluorescent substrate. Because ouabain is now accepted as an endogenous hormone, our results suggest that ABCC1 is regulated by hormones related to body volume control, which may have implications for the treatment of hypertensive cancer patients. Moreover, providing ABCC1 is expressed in several other tissues, such as brain, testis, and the immune system, and is related to the transport of glutathione, it is possible that ouabain release may control a number of functions within these organs and tissues by modulating both the expression and the activity of ABCC1.

Stunted children gain less lean body mass and more fat mass than their non-stunted counterparts: a prospective study.

The aim of the present study was to analyse the changes in body composition of stunted children during a follow-up period and to test the hypothesis of a tendency to accumulate body fat as a consequence of undernutrition early in life. We selected fifty boys and girls aged 11 to 15, who were residents of slums in Sao Paulo, Brazil. Twenty were stunted (S) and thirty had normal stature (NS). The children's nutritional status and body composition were assessed through anthropometry and dual-energy X-ray absorptiometry, at the beginning of the present study and after 3 years, and changes in lean mass (LM and LM%) and fat mass (FM and FM%) were calculated. Stunted boys accumulated more body fat (FM%: S=1.62%, NS=-3.40%; P=0.003) and gained less lean mass (LM%: S=-1.46, NS=3.21%; P=0.004). Stunted girls gained less lean mass (S=7.87 kg, NS=11.96 kg; P=0.032) and had significantly higher values of FM% at follow-up when compared with their baseline values (P=0.008), whereas non-stunted girls had a non-significant difference in FM% over time (P=0.386). These findings are important to understand the factors involved in the increased prevalence of overweight and obesity among poor populations, which appear to be associated with hunger during infancy and/or childhood.

Genetic diversity of Neisseria meningitidis strains isolated in Rio de Janeiro, Brazil, evaluated by multilocus enzyme electrophoresis.

AIMS: To analyse Neisseria meningitidis isolates from meningococcal meningitis cases in Rio de Janeiro (Brazil) from 1990 to 1993 and 1999-2002, to determine the genetic and relatedness with hypervirulent and epidemic strains. METHODS AND RESULTS: The isolates were analysed by multilocus enzyme electrophoresis (MEE) clustering into 83 electrophoretic types (ET). All isolates from 1999 to 2002, formed a cluster which included one strain of the ET-5 complex worldwide associated with epidemics. CONCLUSIONS: The overall results suggested a panmictic structure probably because of recombination events. The observation of a separated cluster including isolates from 1999 to 2002 and an ET-5 complex strain, also suggested the introduction of strains genetically related with this hypervirulent complex in the State of Rio de Janeiro (Brazil) over the last 5 years. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of strains related to the ET-5 complex in several states of Brazil was already described elsewhere, but this is the first time it was reported in the State of Rio de Janeiro. Our findings reinforce the necessity to genetically determine the clones which should be considered to produce a national vaccine against meningococcal meningitis.

PCR analyses of tRNA intergenic spacer, 16S-23S internal transcribed spacer, and randomly amplified polymorphic DNA reveal inter- and intraspecific relationships of Enterobacter cloacae strains.

PCR analysis of tRNA intergenic spacer (tDNA-PCR) and of the 16S-23S internal transcribed spacer (ITS-PCR) and random amplified polymorphic DNA (RAPD) analysis were evaluated for their usefulness in characterization of Enterobacter cloacae strains isolated from both clinical origins and vaccine microbial contamination. tDNA-PCR presented specific and reproducible patterns for Enterobacter sakazakii ATCC 29004, Enterobacter aerogenes ATCC 13048, and Enterobacter cloacae ATCC 13047 and 23355 that presented the same profile for all 16 E. cloacae isolates, offering an alternative tool for species-level identification. ITS-PCR and RAPD analysis yielded completely different banding patterns for the 20 strains studied, except for E. cloacae strains isolated from different batches of vaccine that exhibited a unique pattern, suggesting contamination by the same strain. The combined use of tDNA-PCR and ITS-PCR in a one-step protocol allows accurate identification and typing of E. cloacae strains a few hours after the colony has been isolated.

A neural network with asymmetric basis functions for feature extraction of ECG P waves.

In this work a simple neural network with asymmetric basis functions is proposed as a feature extractor for P waves in electrocardiographic signals (ECG). The neural network is trained using the classical backward-error-propagation algorithm. The performance of the proposed network was tested using actual ECG signals and compared with other types of neural feature extractors.

Fungaemia caused by Hansenula anomala--an outbreak in a cancer hospital.

Yeasts belonging to the genus Hansenula are rarely encountered as the cause of infection in clinical practice. A wide spectrum of infections caused by these fungi can be seen, ranging from asymptomatic fungaemia to severe disease. We describe an outbreak of 24 cases of infection due to H. anomala in an oncological hospital in Rio de Janeiro, Brazil. The median age of the patients was 11 years, of whom 54.2% were female; 91.7% of the Hansenula fungaemia occurred in the haematology unit. The most frequent primary disease diagnosis was leukaemia (62.5%), and all of those infected had had a central venous catheter or peripheral venous catheter and had been treated previously with broad-spectrum antibiotics. Numerous other risk factors were observed in our cases: previous use of steroids, chemotherapy, radiation therapy and neutropenia (data not shown). No deaths could be attributed to Hansenula.