Development of a flotation method for preconcentration-separation of trace amounts of some metal ions in plant tissues prior to their FAAS determinations

An efficient flotation method based on the combination of flame atomic absorption spectrometry (FAAS) and separation and preconcentration step for determination of Cr3+, Cu 2+, Co2+, Ni2+, Zn2+, Cd 2+, Fe3+ and Pb2+ ions in various real samples by the possibility of applying bis(2-hydroxyacetophenone)-1,4-butanediimine (BHABDI) as a new collector was studied. The influence of pH, amount of BHABDI as collector, sample matrix, type and amount of eluting agent, type and amount of surfactant as floating agent, ionic strength and air flow rates i.e. variables affecting the efficiency of the extraction system was evaluated. It is ascertained that metal ions such as iron can be separated simultaneously from matrix in the presence of 0.012 mM ligand, 0.025% (w/v) of CTAB to a test sample of 750 mL at pH 6.5. These ions can be eluted quantitatively with 6 mL of 1.0 mol L-1 HNO3 in methanol which lead to the enrichment factor of 125. The detection limits for analyte ions were in the range of 1.3-2.4 ng mL-1. The method has been successfully applied for determination of trace amounts of ions in various real samples.

Use of a saline gradient for the diagnosis of schistosomiasis

The development of novel methods for parasitological diagnosis that are both highly sensitive and low in cost has been strongly recommended by the World Health Organization. In this study, a new technique for diagnosis of schistosomiasis mansoni is proposed based on the differential sedimentation of eggs when subjected to a slow continuous flux of 3% saline solution through a porous plaque. This influx suspends low-density faecal material, effectively cleaning the sample. The remaining sediment covering the porous plaque surface is then transferred to a glass slide and examined under a bright field microscope. Twelve Kato-Katz slides were used for comparison in the present study. Our results suggest that the saline gradient method detects a signifi-cantly higher number of eggs than the 12 Kato-Katz slides (p < 0.0001). We also found microscopic inspection to be quicker and easier with our newly described method. After cleaning the sample, the obtained sediment can also be conserved in a 10% formaldehyde solution and examined for at least 45 days later without statistically significant egg count differences.

Occurrence of Giardia cysts and Cryptosporidium oocysts in activated sludge samples in Campinas, SP, Brazil

Giardia and Cryptosporidium have caused several outbreaks of gastroenteritis in humans associated with drinking water. Contaminated sewage effluents are recognized as a potential source of waterborne protozoa. Due to the lack of studies about the occurrence of these parasites in sewage samples in Brazil, we compared the efficiency of two procedures for concentrating cysts and oocysts in activated sludge samples of one sewage treatment plant. For this, the samples were submitted to i) concentration by the ether clarification procedure (ECP) and to ii) purification by sucrose flotation method (SFM) and aliquots of the pellets were examined by immunofluorescence. Giardia cysts were present in all samples (100.0%; n = 8) when using ECP and kit 1 reagents, while kit 2 resulted in six positive samples (85.7%; n = 7). As for SFM, cysts were detected in 75.0% and 100.0% of these samples (for kit 1 and 2, respectively). Regarding Cryptosporidium, two samples (25.0%; kit 1 and 28.5% for kit 2) were detected positive by using ECP, while for SFM, only one sample (examined by kit 1) was positive (12.5%). The results of the control trial revealed Giardia and Cryptosporidium recovery efficiency rates for ECP of 54.5% and 9.6%, while SFM was 10.5% and 3.2%, respectively. Considering the high concentration detected, a previous evaluation of the activated sludge before its application in agriculture is recommended and with some improvement, ECP would be an appropriate simple technique for protozoa detection in sewage samples.

ASSESSMENT OF THE PRESENCE OF Toxocara EGGS IN SOILS OF AN ARID AREA IN CENTRAL-WESTERN ARGENTINA

With the aim of studying the contamination of soils with eggs of Toxocara spp. in an arid area in the central-western region of Argentina, 76 soil samples were collected from 18 towns belonging to six provinces of central-western Argentina. They were processed by the centrifugal flotation method. No eggs of Toxocara spp. were found. It can be concluded that the negative results are directly related to the characteristics of the environment and climate present in the studied area. The finding of eggs in soils depends on several factors: the presence of canine or feline feces, the hygienic behavior of pet owners, the presence of stray animals without veterinary supervision, the weather and environmental conditions, and laboratory techniques used; and all these circumstances must be considered when comparing the results found in different geographical regions. In order to accurately define the importance of public spaces in the transmission of infection to humans, it is important to consider the role of backyards or green spaces around housing in small towns, where the population is not used to walking pets in public spaces, and in such cases a significant fraction of the population may acquire the infection within households.

The combination of three faecal parasitological methods to improve the diagnosis of schistosomiasis mansoni in a low endemic setting in the state of Ceará, Brazil

Laboratory diagnosis of intestinal schistosomiasis mansoni can be accomplished through various methods of stool examination to detect parasites, ranging from the most classic tests (Kato-Katz) to several methods that are still undergoing validation. This study was conducted to assess two new parasite identification methods for diagnosing schistosomiasis mansoni in residents of a low endemic area in the municipality of Maranguape, in the state of Ceará, Brazil using the Kato-Katz method as a reference and serology (enzyme-linked immunosorbent assay) for the screening of patients. The Kato-Katz, the saline gradient method and the Helmintex® method parasite identification methods were employed only in subjects who exhibited positive serologic tests. The test results were then analysed and treatment of positive individuals was subsequently performed. After comparing the test results, we observed that the saline gradient method and the Helmintex® method were more effective in diagnosing schistosomiasis mansoni in the study area compared with the Kato-Katz method.

Development of a flotation-spectrophotometric method for determination of cetylpyridinium chloride in pharmaceutical products

A new simple and sensitive flotation-spectrophotometric method for the determination of cetylpyridinium chloride (CPC) is reported. The method is based on the formation of an ion- associate between CPC and Orange II (OR) which is floated in the interface of aqueous phase and n-hexane by vigorous shaking. The aqueous solution was discarded and the adsorbed ion associate on to the wall of a separating funnel was dissolved in a small volume of methanol solvent and its absorbance was measured at 480 nm. The apparent molar absorptivity (Ε) of the ion associate was determined to be 4.12 x 10(5) L mol-1 cm-1. The calibration graph was linear in the concentration range of 15-800 ng mL-1 of CPC with a correlation coefficient of 0.9988. The limit of detection (LOD) was 10.8 ng mL-1. The relative standard deviation (RSD) for determination of 100 and 800 ng mL-1 of CPC was 3.47 and 2.04% (n=7), respectively. The method was successfully applied to the determination of CPC in a commercial mouth washer product.

A simple modification of the Baermann method for diagnosis of strongyloidiasis

The diagnosis of Strongyloides stercoralis infections is routinely made by microscopic observation of larvae in stool samples, a low sensitivity method, or by other, most effective methods, such as the Baermann or agar culture plate methods. We propose in this paper a practical modification of Baermann method. One hundred and six stool samples from alcoholic patients were analyzed using the direct smear test, agar culture plate method, the standard Baermann method, and its proposed modification. For this modification the funnel used in the original version of the method is substituted by a test tube with a rubber stopper, perforated to allow insertion of a pipette tip. The tube with a fecal suspension is inverted over another tube containing 6 ml of saline solution and incubated at 37°C for at least 2 h. The saline solution from the second tube is centrifuged and the pellet is observed microscopically. Larva of S. stercoralis were detected in six samples (5.7%) by the two versions of the Baermann method. Five samples were positive using the agar culture plate method, and only in two samples the larva were observed using direct microscopic observation of fecal smears. Cysts of Endolimax nana and Entamoeba histolytica/dyspar were also detected in the modification of Baermann method. Data obtained by the modified Baermann method suggest that this methodology may helps concentrate larvae of S. stercoralis as efficiently as the original method.

A conventional polymerase chain reaction-based method for the diagnosis of human schistosomiasis in stool samples from individuals in a low-endemicity area

The aim of this study was to evaluate the efficacy of a polymerase chain reaction (PCR)-based method to detect Schistosoma mansoni DNA in stool samples from individuals living in a low-endemicity area in Brazil. Of the 125 initial stool samples, 80 were ELISA reactive and eggs were identified in 19 of the samples by parasitological examination. For the PCR evaluations, 56 stool samples were selected and divided into five groups. Groups I-IV were scored negative for S. mansoni eggs by parasitological examination. Groups I and II were ELISA reactive, whereas Groups III and IV were ELISA nonreactive. Groups II and III were positive for other intestinal parasites. PCR testing scored eight samples as positive from these four groups. Group V represented the S. mansoni -positive group and it included ELISA-reactive samples that were scored positive for S. mansoni by one or more parasitological examinations (6/19 were positive by Kato-Katz method, 9/17 by saline gradient and 10/13 by Helmintex®). PCR scored 13 of these 19 samples as positive for S. mansoni . We conclude that while none of these methods yielded 100% sensitivity, a combination of techniques should be effective for improving the detection of S. mansoni infection in low-endemicity areas.

Effectiveness of heparin versus 0.9% saline solution in maintaining the permeability of central venous catheters: a systematic review

Abstract OBJECTIVE Determining which is the most effective solution (heparin flush compared to 0.9% saline flush) for reducing the risk of occlusions in central venous catheters (CVC) in adults. METHOD The systematic review followed the principles proposed by the Cochrane Handbook; critical analysis, extraction and synthesis of data were performed by two independent researchers; statistical analysis was performed using the RevMan program 5.2.8. RESULTS Eight randomized controlled trials and one cohort study were included and the results of the meta-analysis showed no difference (RR=0.68, 95% CI=0.41-1.10; p=0.12). Analysis by subgroups showed that there was no difference in fully deployed CVC (RR=1.09, CI 95%=0.53-2.22;p=0.82); Multi-Lumen CVC showed beneficial effects in the heparin group (RR=0.53, CI 95%=0.29-0.95; p=0.03); in Double-Lumen CVC for hemodialysis (RR=1.18, CI 95%=0.08-17.82;p=0.90) and Peripherally inserted CVC (RR=0.14, CI 95%=0.01-2.60; p=0.19) also showed no difference. CONCLUSION Saline solution is sufficient for maintaining patency of the central venous catheter, preventing the risks associated with heparin administration.

RAPID AND SENSITIVE DETERMINATION OF PALLADIUM USING HOMOGENEOUS LIQUID-LIQUID MICROEXTRACTION VIA FLOTATION ASSISTANCE FOLLOWED BY GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY

A method for the determination of trace amounts of palladium was developed using homogeneous liquid-liquid microextraction via flotation assistance (HLLME-FA) followed by graphite furnace atomic absorption spectrometry (GFAAS). Ammonium pyrrolidine dithiocarbamate (APDC) was used as a complexing agent. This was applied to determine palladium in three types of water samples. In this study, a special extraction cell was designed to facilitate collection of the low-density solvent extraction. No centrifugation was required in this procedure. The water sample solution was added to the extraction cell which contained an appropriate mixture of extraction and homogeneous solvents. By using air flotation, the organic solvent was collected at the conical part of the designed cell. Parameters affecting extraction efficiency were investigated and optimized. Under the optimum conditions, the calibration graph was linear in the range of 1.0-200 µg L-1 with a limit of detection of 0.3 µg L-1. The performance of the method was evaluated for the extraction and determination of palladium in water samples and satisfactory results were obtained. In order to verify the accuracy of the approach, the standard addition method was applied for the determination of palladium in spiked synthetic samples and satisfactory results were obtained.

Histopathological analysis of rat mesentery as a method for evaluating neutrophil migration: differential effects of dexamethasone and pertussis toxin

In the present study, histopathological analysis of rat mesentery was used to quantify the effect of two anti-inflammatory agents, dexamethasone (Dex) and pertussis toxin (Ptx), on leukocyte migration. The intravenous injection of Dex (1 mg/kg) and Ptx (1,200 ng) 1 h prior to the intraperitoneal injection of the inflammatory stimuli lipopolysaccharide (LPS) or formyl-methionyl-leucyl-phenylalanine (fMLP) significantly reduced the neutrophil diapedesis (LPS: Ptx = 0.86 ± 0.19 and Dex = 0.35 ± 0.13 vs saline (S) = 2.85 ± 0.59; fMLP: Ptx = 0.43 ± 0.09 and Dex 0.01 ± 0.01 vs S = 1.08 ± 0.15 neutrophil diapedesis/field) and infiltration (LPS: Ptx = 6.29 ± 1.4 and Dex = 3.06 ± 0.76 vs S = 15.94 ± 3.97; fMLP: Ptx = 3.85 ± 0.56 and Dex = 0.40 ± 0.16 vs S = 7.15 ± 1.17 neutrophils/field) induced by the two agonists in the rat mesentery. The inhibitory effect of Dex and Ptx was clearly visible in the fields nearest the venule (up to 200 µm), demonstrating that these anti-inflammatory agents act preferentially in the transmigration of neutrophils from the vascular lumen into the interstitial space, but not in cell movement in response to a haptotactic gradient. The mesentery of rats pretreated with Dex showed a decreased number of neutrophils within the venules (LPS: Dex = 1.50 ± 0.38 vs S = 4.20 ± 1.01; fMLP: Dex = 0.25 ± 0.11 vs S = 2.20 ± 0.34 neutrophils in the lumen/field), suggesting that this inhibitor may be acting at a step that precedes neutrophil arrival in the inflamed tissue. In contrast to that observed with Dex treatment, the number of neutrophils found in mesenteric venules was significantly elevated in animals pretreated with Ptx (LPS: Ptx = 9.85 ± 2.25 vs S = 4.20 ± 1.01; fMLP: Ptx = 4.66 ± 1.24 vs S = 2.20 ± 0.34 neutrophils in the lumen/field). This discrepancy shows that Ptx and Dex act via different mechanisms and suggests that Ptx prevents locomotion of neutrophils from the vascular lumen to the interstitial space. In conclusion, the method described here is useful for quantifying the inflammatory and anti-inflammatory effect of different substances. The advantage of this histopathological approach is that it provides additional information about the steps involved in leucocyte migration.

Saline distribution during multicomponent salting in pre-cooked quail eggs

The relationship of NaCl with problems of arterial hypertension has led to a reduction in the levels of this salt in food production. KCl has been used as a partial substitute for NaCl since it cannot be completely substituted without affecting the acceptability of the end product. In this study, the diffusion that occurs during quail egg salting in static and stirred brine was simulated. The mathematical model used was based on a generalization of the Fick's 2nd law, and the COMSOL Multiphysics software was used to simulate the diffusion in the NaCl-KCl-water system. The deviations in the simulated data and experimental data were 2.50% for NaCl and 6.98% for KCl in static brine, while in the stirred brine they were 3.48% for NaCl and 4.72% for KCl. The simulation results presented good agreement with the experimental values and validated the predictive capacity of the model.

Influence of the extraction method and storage time on the physicochemical properties and carotenoid levels of pequi (Caryocar brasiliense Camb.) oil

The objective of this study was to analyze the physicochemical properties and carotenoid levels of pequi oil obtained by different extraction methods and to evaluate the preservation of these properties and pigments during storage time. The pequi oil was obtained by solvent extraction, mechanical extraction, and hot water flotation. It was stored for over 180 days in an amber bottle at ambient conditions. Analyses for the determination of the acidity, peroxide, saponification and iodine values, coloration, total carotenoids, and β-carotene levels were conducted. The oil extraction with solvents produced the best yield and carotenoid levels. The oil obtained by mechanical extraction presented higher acidity (5.44 mg KOH.g-1) and peroxide values (1.07 mEq.kg-1). During the storage of pequi oil, there was an increase in the acidity and the peroxide values, darkening of the oil coloration, and a reduction of the carotenoid levels. Mechanical extraction is the less advantageous method for the conservation of the physicochemical properties and carotenoid levels in pequi oil.

Multiple centroid method to evaluate the adaptability of alfalfa genotypes

This study aimed to evaluate the efficiency of multiple centroids to study the adaptability of alfalfa genotypes (Medicago sativa L.). In this method, the genotypes are compared with ideotypes defined by the bissegmented regression model, according to the researcher's interest. Thus, genotype classification is carried out as determined by the objective of the researcher and the proposed recommendation strategy. Despite the great potential of the method, it needs to be evaluated under the biological context (with real data). In this context, we used data on the evaluation of dry matter production of 92 alfalfa cultivars, with 20 cuttings, from an experiment in randomized blocks with two repetitions carried out from November 2004 to June 2006. The multiple centroid method proved efficient for classifying alfalfa genotypes. Moreover, it showed no unambiguous indications and provided that ideotypes were defined according to the researcher's interest, facilitating data interpretation.