Aguinaldo José do Nascimento

Hospital gowns as a vehicle for bacterial dissemination in an intensive care unit

The microbiota from the uniforms of 31 professionals from the general intensive care unit was analyzed. The samples were collected in duplicate at the beginning and at the end of the work period. Total viable counts of microorganisms were determined; there was a significant increase in the counts at the end of the period, when compared with those obtained at the beginning. No significant difference was observed between the first and second counts obtained from the cuffs. However, differences were observed for the samples from the abdominal region. Among the isolated pathogens 11/18 were Staphylococcus aureus, 2/18 were Acinetobacter baumannii, 2/18 were Klebsiela pneumoniae and 1/18 were Serratia rubidae. Some of these isolates were multi-resistant to antibiotics. Emphasis should be placed on reducing the spread of these pathogens in the hospital, making sure that biosafety protocols are followed by the staff.

Oxidative process in erythrocytes of individuals with hemoglobin S

Abstract The understanding of the oxidative stress mechanisms helps to explain many of the processes of cellular lesion and death, especially those related to the hemolytic diseases. Sickle cell anemia, thalassemias and G6-PD deficiency are among the more frequent genetic anomalies accompanied by oxidative stress. In the sickle cells, one of the factors that predisposes to the hemolytic process is the oxidative degradation of the hemoglobin S due to its deoxigenation leading to hemichrome formation and precipitation as Heinz bodies. The oxidative stress contributes to the sickle process and shortening of the erythrocyte survival. Here we analyzed the oxidative process in erythrocytes of patients with two different genotypes for HbS (AS and SS). Units of blood from donors of the Center of Hematology and Hemotherapy of Paraná (HEMEPAR), from normal individuals (AA) and from heterozygote individuals (AS), and venous blood collected from patients with sickle cell anemia (SS) were analyzed. In order to evaluate the protective action of the vitamins C and E in oxidative stress, erythrocytes were treated with antioxidant substances, vitamin C and vitamin E, and then treated with the oxidant tert-butilhydroperoxide (TBHP). The oxidative action induced by TBHP was observed in erythrocytes AA<AS<SS, by the increase in the content of Heinz bodies, methemoglobin, hemolysis, GSH depletion and lowering activities of the enzymes G6-PD and GR. The protective actions of the vitamins C and E for the oxidative stress induced by TBHP were observed for the erythrocytes in the lowering Heinz bodies, methemoglobin, hemolysis, and partial recovery of GSH more efficiently in AS and SS erythrocytes. Recovery was not observed in the levels of the activities of the enzymes G6-PD and GR, under the vitamins actions. The results obtained confirmed the higher susceptibility of the sickle erythrocyte to oxidation which necessitates precaution in the transfusion adequacy of AS erythrocytes. On the other hand, the protective effect of the vitamins C and E over the oxidative stress observed in erythrocytes AS and SS open perspectives for their use for treatment of patients with sickle cell anemias, as well as in the preservation of transfusional erythrocyte bag units.

Colorimetric determination of alpha and beta-cyclodextrins and studies on optimization of CGTase production from B. firmus using factorial designs

Cyclodextrin glycosyltransferase (EC 2.4.1.19, CGTase) production from B. firmus, isolated from soil of Curitiba, PR, was optimized in shake flask using an experimental design approach. The CGTase was produced when the carbon source was starch and b-CD, but when simple sugars such as glucose, galactose, lactose, sucrose, and maltose were used, there was no enzyme production. CGTase production was the same with either organic nitrogen or inorganic nitrogen source. CGTase activity decreased 2-fold when incubation temperature was increased from 28 to 37 ° C, and decreased 2.1- fold when the initial pH was lowered from 10.3 to 7.4. The colorimetric determinations of a - and b -CD were analyzed as a non-linear relationship and the equilibrium constant for a -CD/methyl orange and b -CD/phenolphthalein complexes were 7.69 x 103 L / mol and 2.33 x 103 L/ mol, respectively.

Effect of amiodarone (AMD) on the antioxidant enzymes, lipid peroxidation and mitochondrial metabolism

The effects of amiodarone (AMD) on lipid peroxidation of rat liver mitochondria, the formation of superoxide anions at the respiratory chain level, and the cytosolic and mitochondrial enzymatic protective mechanisms of oxidative stress were studied. An attempt to classify AMD according to its toxic ability to interfere with the integrated function of electron transport enzymes was also investigated. The results confirm the effects of AMD on complex I and permit the placing of this drug in class A of the classification of Knobeloch, together with rotenone, amytal and chaotropic agents. AMD has no effect on the activity of the enzymes superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase, nor on glucose 6‐phosphate dehydrogenase. AMD did not promote an increase in the formation of anion superoxide at the respiratory chain level. Pre‐incubation with AMD (16·6 μM) inhibited about 70 per cent of lipid peroxidation. The results suggest a protective effect of AMD against lipid peroxidation in mitochondrial membranes by iron‐dependent systems.

Isolation of alkalophilic CGTase-producing bacteria and characterization of cyclodextrin-glycosyltransferase

One hundred and twenty five soil samples were collected from the regions of roots of corn, cassava, potato, bean, sugar cane, soya, and pumpkin. From these, 75 strains were isolated that produced a yellowish halo surrounding the colonies, due to a phenolphtalein-cyclodextrin (CD) complex, and these were selected as alkalophilic CGTase-producing bacteria. All the 75 strains were identified as Bacillus firmus by microscopy and biochemical tests. The activity of the CGTases varied from 22 to 210 dilutions,when assayed by CD-trichloroethylene (TCE)-complex precipitation. Strain 31 that produced the enzyme at the higher level was selected, and its enzyme was partially purified by starch adsorption (x 17) in a yield of 51%. Maximum enzyme activity occurred at pH 5.5 and 8.5. At pH 5.5, the optimum temperature was 60°C. On increased from 30°C to 85°C, the thermodynamic parameter for activation energy was 8.27 kcal.mol-1. The enzyme was inhibited by Ca2+, Mg2+, Fe2+, Cu2+, Mn2+, and Zn2+.

Effect of vitamin C, deferoxamine, quercetin and rutin against tert-butyl hydroperoxide oxidative damage in human erythrocytes

Abstract The mature human erythrocyte, when submitted to oxidative stress, can demonstrate depletion of reduced glutathione, oxidation of the hemoglobin molecule and aggregation of complexes of iron close to the membrane. These can produce abnormalities in the erythrocyte membrane and hemolysis. The aim of this work was to study the antioxidative action of vitamin C (vit. C), deferroxamine (DFO) and the flavonoids quercetin and rutin in normal human erythrocytes, submitted to in vitro oxidative stress induced by tert-butylhydroperoxide (tBHP). Venous blood was colleted in citrate–phosphate–dextrose (CPD) solution, as anticoagulant, from healthy adult individuals after informed consent. The erythrocytes were resuspended in PBS to obtain 35% globular volume, and then submitted to the oxidative action of tBHP for up to 30 min, with or without previous incubation for 60 min with vit. C, DFO, quercetin and rutin. Decrease in the GSH concentration, G6-PD and GR activities, and increase in the methemoglobin and Heinz bodies (HB) formation, occurred with the increase in tBHP concentration. tBHP did not effect on the membrane proteins detected by SDS-PAGE. Quercetin, partially prevented the GSH decrease and the formation of HB, but did not prevent MetHb formation from oxidative damage by tBHP. Rutin, after tBHP induction, prevented the GSH decrease and the formation of HB. Vit. C, had no influence on the depletion of GSH, inhibited partially the metHb formation, and it protected GR, but not G6-PD from oxidative damage by tBHP. DFO partially inhibited the metHb formation and GSH decrease, but it did not protect GR and G6-PD from oxidative damage by tBHP. The results obtained suggest that vit. C, DFO and the flavonoids quercetin and rutin contribute to the decrease in the oxidative stress caused by tBHP.

Occurrence of extended-spectrum beta-lactamases in Enterobacteriaceae isolated from hospitalized patients in Curitiba, southern Brazil

Production of extended-spectrum beta-lactamases (ESBL) by enterobacteria is an important resistance mechanism against antimicrobial beta-lactamics. We tested 498 bacterial strains isolated from two tertiary-care teaching hospitals for ESBL production, using screening breakpoints for aztreonam and third generation cephalosporins, according to CLSI recommendations. Among these isolates, 155 were positive for the ESBL screening test, and 121 (78%) were confirmed by the clavulanic acid combination disk method. We found a high frequency of ESBL (24%) among Enterobacteriaceae, with a frequency of 57.4% for Klebsiella pneumoniae, 21.4% for Klebsiella oxytoca, and 7.2% for E. coli. In other members of Enterobacteriaceae, non-Klebsiella and non-E. coli, the prevalence was 21.6%. Ceftriaxone and cefotaxime showed a higher sensitivity in the screening test (99.2%) when compared to ceftazidime, aztreonam and cefpodoxime. However, cefotaxime/cefotaxime plus clavulanic acid showed a higher sensitivity in the confirmatory test (96.7%).

N-acetylcysteine as a potential strategy to attenuate the oxidative stress induced by uremic serum in the vascular system

AIMS Chronic kidney disease (CKD) progression is accompanied by systemic oxidative stress, which contributes to an increase in the risk of cardiovascular diseases (CVDs). N-acetylcysteine (NAC) is among the most studied antioxidants, but its therapeutic benefits in CKD-associated CVDs remain controversial. Here, we investigated whether NAC could inhibit the oxidative stress induced by uremia in vitro and in vivo. MAIN METHODS Endothelial and smooth muscle cells were challenged with human uremic or non-uremic sera, and the effects of a pre-treatment with 2mM NAC were evaluated. Reactive oxygen species (ROS) production, protein oxidation and total glutathione/glutathione disulfide (tGSH/GSSG) ratios were measured. Five-sixths nephrectomized or sham-operated rats were orally treated (in the drinking water) with 60 mg/kg/day NAC or not treated for 53 days. Plasma cysteine/cystine reduction potential Eh(Cyss/2Cys) was determined as a novel marker of the systemic oxidative stress. KEY FINDINGS NAC inhibited all the determined oxidative stress parameters, likely by increasing the tGSH/GSSG ratio, in both cell lines exposed to uremic serum. Orally administered NAC attenuated the systemic oxidative stress in uremic rats. SIGNIFICANCE The present results indicate that NAC, by preventing GSH depletion in vascular cells exposed to uremic serum and by attenuating the systemic oxidative stress during CKD progression, emerges as a potential strategy to prevent the oxidative stress induced by uremic toxicity in the vascular system.

Toxoplasma gondii in goats from Curitiba, Paraná, Brazil: risks factors and epidemiology

Toxoplasmosis is a zoonosis caused by Toxoplasma gondii, a protozoan with wide geographical distribution and minimal parasitic specificity that affects many species of wild and domestic animals. In livestock, especially in small ruminants like goats, toxoplasmosis can cause abortion and the birth of weak animals, leading to economic losses to farmers, and is a major source of human infection. This is a seroepidemiological study of toxoplasmosis in goats in the state of Paraná, Brazil. Sera from 405 goats from the metropolitan mesoregion of Curitiba, eastern state, were tested by the enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence antibody test (IFAT). Information on properties and goat characteristics was also collected using questionnaires. The prevalence of toxoplasmosis was 39.41 and 35.96% by ELISA and IFAT, respectively. T. gondii antibody prevalence increased with age. The risk factors for T. gondii infection in goats were: age over one year; exposure to cats, type of management and purpose of breeding. Other epidemiological factors and relevant control measures are discussed in the current study.

Erythrocyte oxidative stress markers in children with sickle cell disease

Objective To determine eight parameters of oxidative stress markers in erythrocytes from children with sickle cell disease and compare with the same parameters in erythrocytes from healthy children, since oxidative stress plays an important role in the pathophysiology of sickle cell disease and because this disease is a serious public health problem in many countries.OBJECTIVE To determine eight parameters of oxidative stress markers in erythrocytes from children with sickle cell disease and compare with the same parameters in erythrocytes from healthy children, since oxidative stress plays an important role in the pathophysiology of sickle cell disease and because this disease is a serious public health problem in many countries. METHODS Blood samples were obtained from 45 children with sickle cell disease (21 males and 24 females with a mean age of 9 years; range: 3-13 years) and 280 blood samples were obtained from children without hemoglobinopathies (137 males and 143 females with a mean age of 10 years; range: 8-11 years), as a control group. All blood samples were analyzed for methemoglobin, reduced glutathione, thiobarbituric acid reactive substances, percentage of hemolysis, reactive oxygen species, and activity of the enzymes glucose 6-phosphate dehydrogenase, superoxide dismutase, and catalase. Data were analyzed using Students t-test and were expressed as the mean±standard deviation. A p-value of <0.05 was considered significant. RESULTS Significant differences were observed between children with sickle cell disease and the control group for the parameters methemoglobin, thiobarbituric acid reactive substances, hemolysis, glucose 6-phosphate dehydrogenase activity, and reactive oxygen species, with higher levels in the patients than in the controls. CONCLUSIONS Oxidative stress parameters in childrens erythrocytes were determined using simple laboratory methods with small volumes of blood; these biomarkers can be useful to evaluate disease progression and outcomes in patients.