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1.
Biochem Biophys Rep ; 24: 100814, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33015376

RESUMO

A major challenge in hepatitis C research is the detection of early potential for progressive liver disease. MicroRNAs (miRNAs) are small RNAs that regulate gene expression and can be biomarkers of pathological processes. In this study, we compared circulating miRNAs identified in hepatitis C virus (HCV)-infected patients presenting two extremes of liver disease: mild/moderate fibrosis and cirrhosis. The patients in the cirrhosis group subsequently developed hepatocellular carcinoma (HCC). We identified 163 mature miRNAs in the mild/moderate fibrosis group and 171 in the cirrhosis group, with 144 in common to both groups. Differential expression analysis revealed 5 upregulated miRNAs and 2 downregulated miRNAs in the cirrhosis group relative to the mild/moderate fibrosis group. Functional analyses of regulatory networks (target gene and miRNA) identified gene categories involved in cell cycle biological processes and metabolic pathways related to cell cycle, cancer, and apoptosis. These results suggest that the differentially expressed circulating miRNAs observed in this work (miR-215-5p, miR-483-5p, miR-193b-3p, miR-34a-5p, miR-885-5p, miR-26b-5p and miR -197-3p) may be candidates for biomarkers in the prognosis of liver disease.

2.
J Viral Hepat ; 25(11): 1244-1250, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29768686

RESUMO

A novel controlled attenuation parameter (CAP) using FibroScan® has been developed for assessment of liver steatosis. The aim was to evaluate the frequency and associated factors for moderate/severe steatosis evaluated by CAP in CHC patients submitted to transient elastography (TE) by FibroScan® . CHC patients underwent TE with CAP evaluation. The classification of steatosis was defined as: CAP < 222 dB/m  =  S0; CAP ≥ 222 dB/m and <233dB/m  =  S1; ≥233 dB/m < 290dB/m  =  S2 and >= 290 dB/m  =  S3. The prevalence of moderate/severe steatosis (CAP ≥ S2) and the related independent factors were identified by a logistic regression analysis. A significance level of 5% was adopted. 1104 CHC patients, 85% genotype-1 were included (mean age 55 ± 11 years; 46% male, mean BMI 25 ± 4 Kg/m2 ). Systemic arterial hypertension and type 2 diabetes mellitus prevalences were 39% and 17%, respectively. Liver stiffness measurement ≥ 9.5 kPa was observed in 39% of patients and steatosis was identified in 50% (S1 = 7%, S2 = 28% and S3 = 15%). The variables independently associated with moderate/severe steatosis were: male gender (OR=1.35; P = .037; 95% CI:1.01-1.81); systemic arterial hypertension (OR=1.57; P = .002; 95% CI:1.17-2.10) and BMI (OR=1.17; P < .01;95% CI:1.12-1.22). In conclusion, when CAP was adopted as a tool to detect steatosis, genotype 1 CHC patients presented a high prevalence of moderate/advanced steatosis. In these patients, liver steatosis was associated mostly to metabolic factors (arterial hypertension and high BMI).


Assuntos
Técnicas de Imagem por Elasticidade , Hepatite C Crônica/diagnóstico por imagem , Hepatite C Crônica/epidemiologia , Hepatopatia Gordurosa não Alcoólica/diagnóstico por imagem , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Adulto , Idoso , Brasil/epidemiologia , Estudos Transversais , Feminino , Hepatite C Crônica/patologia , Hepatite C Crônica/fisiopatologia , Humanos , Fígado/diagnóstico por imagem , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/patologia , Hepatopatia Gordurosa não Alcoólica/fisiopatologia , Valor Preditivo dos Testes , Prevalência , Estudos Retrospectivos , Fatores de Risco
3.
J Viral Hepat ; 25(3): 254-261, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29091323

RESUMO

Chronic infection with the hepatitis C virus induces liver fibrosis, but it is unknown why some patients progress to advanced fibrosis while others remain with mild disease. Recently, an inverse association between serum levels of dehydroepiandrosterone sulphate (DHEA-S) and liver fibrosis in patients with nonalcoholic fatty liver disease was described, and it was postulated that dehydroepiandrosterone (DHEA) has antifibrotic effects. Our aim was to compare serum DHEA-S levels with liver fibrosis in hepatitis C patients. We collected serum samples from hepatitis C patients at the same day they underwent a liver biopsy. S-DHEA was compared to different stages of fibrosis. Binary logistic regression models were applied to evaluate independent variables associated to fibrosis. We included 287 patients (43.9% male). According to fibrosis stages 0, 1, 2, 3 and 4, median serum DHEA-S levels were 103 (26-462), 73 (5-391), 46 (4-425), 35 (6-292) and 28 (2-115) µg/dL, respectively (P < .001). Median serum DHEA-S levels were 74 (5-462) vs 36 (2-425) µg/dL for mild (F0-1) vs significant (F2-4) fibrosis, respectively (P < .001). Median serum DHEA-S levels were 64 (4-462) vs 31 (2-292) µg/dL for non advanced (F0-2) vs advanced fibrosis (F3-4), respectively (P < .001). The same association was found when the subgroup of HCV patients with and without steatosis or steatohepatitis was analysed. The association between lower DHEA-S levels and advanced fibrosis was independent of age, gender, diabetes mellitus, obesity and steatosis. Lower circulating DHEA-S levels are associated with more advanced stages of liver fibrosis in hepatitis C patients.


Assuntos
Sulfato de Desidroepiandrosterona/sangue , Hepatite C Crônica/complicações , Cirrose Hepática/patologia , Adolescente , Adulto , Idoso , Biópsia , Estudos Transversais , Feminino , Histocitoquímica , Humanos , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
4.
Oral Dis ; 23(8): 1072-1079, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28544047

RESUMO

BACKGROUND: This study aims to compare the efficiency of four oral fluid collection methods (Salivette, FTA Card, spitting and DNA-Sal) to detect HBV DNA by qualitative PCR. MATERIALS AND METHODS: Seventy-four individuals (32 HBV reactive and 42 with no HBV markers) donated serum and oral fluid. In-house qualitative PCR to detect HBV was used for both samples and commercial quantitative PCR for serum. RESULTS: HBV DNA was detected in all serum samples from HBV-infected individuals, and it was not detected in control group. HBV DNA from HBV group was detected in 17 samples collected with Salivette device, 16 samples collected by FTA Card device, 16 samples collected from spitting and 13 samples collected by DNA-Sal device. Samples that corresponded to a higher viral load in their paired serum sample could be detected using all oral fluid collection methods, but Salivette collection device yielded the largest numbers of positive samples and had a wide range of viral load that was detected. CONCLUSION: It was possible to detect HBV DNA using all devices tested, but higher number of positive samples was observed when samples were collected using Salivette device, which shows high concordance to viral load observed in the paired serum samples.


Assuntos
DNA Viral/análise , Vírus da Hepatite B , Hepatite B/diagnóstico , Saliva/química , Manejo de Espécimes/métodos , Adolescente , Adulto , Idoso , DNA Viral/sangue , DNA Viral/isolamento & purificação , Feminino , Hepatite B/sangue , Vírus da Hepatite B/genética , Humanos , Masculino , Pessoa de Meia-Idade , Saliva/virologia , Carga Viral , Adulto Jovem
5.
Genet Mol Res ; 14(4): 15996-6005, 2015 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-26662392

RESUMO

Hancornia speciosa, popularly known as mangabeira, is a fruit tree native to the Brazilian Cerrado that shows great economic potential, due to its multiple uses. Intraspecific classification of this species is difficult because it shows high morphological diversity. An early study of the species reported that there are six botanic varieties that differ morphologically mainly in the shapes of their leaves and flowers. Except to note the wide morphological variation and economic potential of this species, few studies have been published about the genetic diversity of mangabeira. Knowledge of the genetic variability of this species among populations would be useful for genetic conservation and breeding programs. Therefore, we tested the transferability of 12 simple sequence repeats from expressed sequence tags (EST-SSRs) from Catharanthus roseus to H. speciosa and used 10 random amplified polymorphic DNA markers to evaluate the genetic variability among botanical varieties of H. speciosa. We obtained a high transferability frequency of EST-SSR markers from C. roseus to H. speciosa (75%). However, EST-SSR markers showed low heterozygosity and locus variability (two or three alleles by locus), which suggest low genetic diversity in the mangabeira samples. The Jaccard dissimilarity index and an examination of geographic distances indicated a non-spatial structuring of the genetic variability. Our markers were unable to distinguish H. speciosa botanical varieties.


Assuntos
Marcadores Genéticos , Repetições de Microssatélites , Polimorfismo Genético , Traqueófitas/classificação , Traqueófitas/genética , Cruzamento , Genética Populacional , Fenótipo , Filogenia , Filogeografia , Técnica de Amplificação ao Acaso de DNA Polimórfico , Especificidade da Espécie
6.
J Hazard Mater ; 278: 82-90, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-24953939

RESUMO

The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. This paper focuses on the development of a leaching process using cupric chloride as oxidising agent, in HCl media, for recovery of palladium and rhodium from a spent catalyst. The chloride media allows the adequate conditions for oxidising and solubilising the metals, as demonstrated by equilibrium calculations based on thermodynamic data. The experimental study of the leaching process revealed that Pd solubilisation is clearly easier than that of Rh. The factors temperature, time, and HCl and Cu(2+) concentrations were significant regarding Pd and Rh leaching, the latter requiring higher factor values to achieve the same results. Leaching yields of 95% Pd and 86% Rh were achieved under optimised conditions (T = 80 °C, t = 4h, [HCl] = 6M, [Cu(2+)] = 0.3M).


Assuntos
Cobre/química , Ácido Clorídrico/química , Paládio/química , Ródio/química , Automóveis , Catálise , Oxirredução , Reciclagem/métodos , Temperatura , Resíduos
7.
Environ Technol ; 34(9-12): 1283-95, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24191461

RESUMO

Physical and chemical characterization of several sizes and shapes of alkaline and saline spent Zn-MnO2 batteries was carried out, aiming at contributing for a better definition of the applicable recycling processes. The characterization essays included the mass balance of the components, cathode and anode elemental analysis, the identification of zinc and manganese bearing phases and the morphology analysis of the electrode particles. The electrode materials correspond to 64-79% of the total weigh of the batteries, with the cathodes having clearly the highest contribution (usually more than 50%). The steel components, mainly from the cases, are also important (17-30%). Elemental analysis showed that the electrodes are highly concentrated in zinc (from 48-87% in anodes) and manganese (from 35-50% in cathodes). X-Ray powder diffraction allowed for identifying several phases in the electrodes, namely zinc oxide, in the anodes of all the types of saline and alkaline batteries tested, while zinc hydroxide chloride and ammine zinc chloride only appear in some types of saline batteries. The manganese found in the cathode materials is present as two main phases, MnO x Mn2O3 and ZnO x Mn2O3, the latter corroborating that zinc migration from anode to cathode occurs during the batteries lifespan. A unreacted MnO2 phase was also found presenting a low crystalline level. Leaching trials with diluted HCI solutions of alkaline and saline battery samples showed that all zinc species are reactive attaining easily over than 90% leaching yields, and about 30% of manganese, present as Mn(II/III) forms. The MnO2 phase is less reactive and requires higher temperatures to achieve a more efficient solubilization.


Assuntos
Equipamentos e Provisões Elétricas , Compostos de Manganês/química , Reciclagem/métodos , Compostos de Zinco/química , Eletrodos , Ácido Clorídrico , Concentração de Íons de Hidrogênio , Manganês/análise , Manganês/química , Cloreto de Sódio/química , Difração de Raios X , Zinco/análise , Zinco/química
8.
J Clin Virol ; 57(2): 98-102, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23518440

RESUMO

BACKGROUND: Enzyme immunoassays (EIA) designed to detect hepatitis C virus (HCV) core antigen and anti-HCV antibodies (HCV AgAb) simultaneously can improve the early detection of HCV infection when molecular diagnostic methods are not widely available. OBJECTIVES: To evaluate the suitability of dried blood spot (DBS) samples for detecting HCV AgAb using commercial EIAs. STUDY DESIGN: Paired serum and DBS samples were assayed using two commercial EIAs for HCV AgAb (Monolisa™ HCV AgAb ULTRA and Murex HCV AgAb). Manufacturer's recommendations were followed for sera while sample volume, incubation time and cut-off (CO) determination were evaluated for the DBS samples. The values of sensitivity, specificity, inter-rater agreement, detection limit, assay precision and stability of DBS samples at different conditions (22-26°C, 2-8°C and -20°C) were determined. RESULTS: It was necessary to increase the DBS sample volume fourfold compared to the sera samples to approximate the DBS Optical Density (OD) values to the sera OD values. Using ROC curve to recalculate CO values for the DBS samples, sensitivity was 97.5% for both EIAs, while the specificity was 99.71% for Monolisa™ HCV AgAb ULTRA and 95.95% for Murex HCV AgAb. Accurate testing results were obtained with DBS samples for 60 days at all conditions evaluated; storage at -20°C resulted in low OD variation. Both EIAs demonstrated the same limit of detection among DBS samples [estimated viral load of 3.1 International Units per millilitre (IU/mL)] and low OD value variability in repetitivity and reproducibility studies. CONCLUSION: DBS samples can be used for the detection of HCV AgAb by EIA as they present comparable performance characteristics and excellent stability among various storage conditions.


Assuntos
Teste em Amostras de Sangue Seco/métodos , Hepacivirus/imunologia , Anticorpos Anti-Hepatite C/sangue , Antígenos da Hepatite C/sangue , Hepatite C/diagnóstico , Adulto , Ensaio de Imunoadsorção Enzimática , Feminino , Hepatite C/sangue , Hepatite C/imunologia , Hepatite C/virologia , Anticorpos Anti-Hepatite C/imunologia , Antígenos da Hepatite C/imunologia , Humanos , Técnicas Imunoenzimáticas/métodos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
9.
J Med Virol ; 84(10): 1600-7, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22930508

RESUMO

This study was undertaken to optimize and compare the efficiency of two commercial EIAs for anti-HCV detection (HCV Ab Radim, Pomezzia, Italy and ETI-AB-HCVK-4 DiaSorin, Vercelli, Italy), in dried blood spot (DBS) samples. The long-term stability of anti-HCV on DBS samples stored at three environmental conditions was also evaluated at: 2-8 °C, 20-25 °C, and -20 °C. Paired DBS and serum samples were obtained from individuals with or without anti-HCV. The type of elution buffer, sample and conjugate volume, sample incubation time and cut-off values were evaluated. For both EIAs, a larger sample volume was used, and the cut-off value determined by the manufacturer was employed for Radim EIA; however, ROC curve analysis was used for the DiaSorin EIA. The sensitivity and specificity of Radim EIA on DBS were 97.5% and 99.5%, respectively, and of DiaSorin EIA were 88.9% and 98.9%, respectively. Accurate results were obtained for a period of 117 days using DBS samples stored at all storage conditions, but storage at -20 °C resulted in the lowest variation among the absorbance values. Both EIAs demonstrated the same limit of detection (until dilution of 1:10(4) with estimated viral load of 3.1 × 10(-1) UI/ml), but the Radim EIA was associated with the best performance because a low coefficient of variation was observed in the repetition and reproducibility studies. In conclusion, commercial EIAs can be optimized for anti-HCV detection in DBS samples that are extremely stable at different conditions for more than 100 days.


Assuntos
Sangue/imunologia , Dessecação , Anticorpos Anti-Hepatite C/sangue , Hepatite C/diagnóstico , Manejo de Espécimes/métodos , Adulto , Técnicas de Laboratório Clínico/métodos , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Temperatura , Adulto Jovem
10.
J Oral Pathol Med ; 41(10): 793-800, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22690929

RESUMO

BACKGROUND: Saliva samples can be used as an alternative fluid for against hepatitis C virus (anti-HCV) detection owing to the ease of collection and excellent acceptability. This study was conducted to optimize a commercial enzyme immunoassay (EIA) to detect anti-HCV in saliva samples. METHODS: Ninety-six individuals donated paired serum and saliva samples that were obtained, using a commercial device (Salivette) and spitting into a sterile container. Initially, elution buffer for the Salivette samples, sample volume, incubation time and temperature, and two different anti-HCV EIAs were evaluated. Using the optimized assay, three methods for cut-off calculation were also evaluated. RESULTS: A 20-fold increase in the sample volume for both collection methods was needed. Moreover, the Radim assay was the most appropriate assay for anti-HCV detection in saliva samples, and the quality parameters were increased when a ROC curve was used to determine the cut-off value. Using this optimized assay, the sensitivities, specificities, accuracies, positive and negative predictive values were above 90% for saliva obtained using both the Salivette and spitting methods. Using this assay, discordant false-negative results were obtained for only two Salivette samples and five spitting samples. The concordance kappa was 93% for the Salivette method and 86.1% for the spitting method, demonstrating excellent performance. CONCLUSIONS: Saliva samples obtained for both methods can be employed for anti-HCV detection among HCV-infected or HCV-suspected cases, but several modifications must be performed on commercial EIAs to obtain good results. Moreover, samples obtained with commercial devices are more appropriate for anti-HCV detection in saliva samples.


Assuntos
Anticorpos Anti-Hepatite C/análise , Saliva/imunologia , Proteínas e Peptídeos Salivares/imunologia , Manejo de Espécimes/métodos , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Técnicas Imunoenzimáticas/métodos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Reprodutibilidade dos Testes , Saliva/química , Sensibilidade e Especificidade , Adulto Jovem
11.
Environ Technol ; 33(1-3): 359-66, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22519122

RESUMO

At the end of their life, Ni-Cd batteries cause a number of environmental problems because of the heavy metals they contain. Because of this, recycling of Ni-Cd batteries has been carried out by dedicated companies using, normally, pyrometallurgical technologies. As an alternative, hydrometallurgical processes have been developed based on leaching operations using several types of leachants. The effect of factors like temperature, acid concentration, reaction time, stirring speed and grinding of material on the leaching yields of metals contained in anodic and cathodic materials (nickel, cadmium and cobalt) using sulphuric acid, is herein explained based on the structural composition of the electrode materials. The nickel, cobalt and cadmium hydroxide phases, even with a small reaction time (less than 15 minutes) and low temperature (50 degrees C) and acid concentration (1.1 M H2SO4), were efficiently leached. However, leaching of the nickel metallic phase was more difficult, requiring higher values of temperature, acid concentration and reaction time (e.g. 85 degrees C, 1.1 M H2SO4 and 5 h, respectively) in order to obtain a good leaching efficiency for anodic and cathodic materials (70% and 93% respectively). The stirring speed was not significant, whereas the grinding of electrode materials seems to promote the compaction of particles, which appears to be critical in the leaching of Ni degrees. These results allowed the identification and understanding of the relationship between the structural composition of electrode materials and the most important factors that affect the H2SO4 leaching of spent Ni-Cd battery electrodes, in order to obtain better metal-recovery efficiency.


Assuntos
Metalurgia/métodos , Metais Pesados/isolamento & purificação , Reciclagem/métodos , Ácidos Sulfúricos/química , Eletrodos , Temperatura
12.
Arq. bras. med. vet. zootec ; 62(5): 1250-1254, out. 2010. tab
Artigo em Português | LILACS | ID: lil-570486

RESUMO

The influence of age, breed, and parity on hemogram and protein profile was evaluated in Canchim-Nelore and Holstein calves, born from primiparous or multiparous cows. Blood samples were taken from 12 to 24h after birth and at 7, 15, and 30 days of age, in which hemogram, total protein, albumin and globulin concentrations were determined. Lymphocyte count was the only parameter influenced by age of calf. Canchim-Nelore calves born from primiparous cows presented significant alterations in hemoglobin, globular volume, and mature neutrophil count; while calves from multiparous cows showed total protein, albumin, and globulins influenced by age. In Holstein calves from primiparous cows, the age influenced globular volume, mature neutrophil count, and albumin levels; while in calves from multiparous cows the age influenced on erythrocyte count, MCV, MCH, and mature neutrophil count. The alterations noted in total protein and albumin and globulin levels were not uniform among groups.


Assuntos
Animais , Recém-Nascido , Bovinos , Bovinos/sangue , Testes Hematológicos , Paridade , Contagem de Células Sanguíneas , Proteínas Sanguíneas
13.
Environ Pollut ; 145(1): 279-92, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16777290

RESUMO

Tillandsia usneoides L. is an epiphytic bromeliad plant able to absorb water and nutrients directly from the air. For this reason this species was selected to carry out a monitoring study of air pollution in the metropolitan region of São Paulo, Brazil. Five consecutive transplantation experiments (8 weeks each) were performed in 10 sites of the city, submitted to different sources of air pollution (industrial, vehicular), using plants collected from an unpolluted area. After exposure, trace metals were analyzed in the plant by instrumental neutron activation analysis. Traffic-related elements such as Zn and Ba presented high concentrations in exposure sites near to heavy traffic avenues (cars, buses and trucks) and may be associated to vehicular sources. For Zn and Co the highest contents were related to industrial zones and can be associated to the presence of anthropogenic emission sources. The rare earth elements, Fe and Rb, probably have soil particles as main source.


Assuntos
Poluentes Atmosféricos/análise , Metais/análise , Tillandsia/química , Bário/análise , Biomarcadores/análise , Brasil , Cidades , Cobalto/análise , Exposição Ambiental/efeitos adversos , Monitoramento Ambiental/métodos , Indústrias , Ferro/análise , Análise de Ativação de Nêutrons/métodos , Medição de Risco/métodos , Rubídio/análise , Poluentes do Solo/análise , Emissões de Veículos/análise , Zinco/análise
14.
Waste Manag ; 27(11): 1570-9, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17166709

RESUMO

The present work aimed at the chemical and physical characterization of spent sealed MONO-type Ni-Cd batteries, contributing to a better definition of the recycling process of these spent products. The electrode material containing essentially nickel, cadmium and some cobalt corresponds to approximately 49% of the weight of the batteries. The remaining components are the steel parts from the external case and the supporting grids (40%) containing Fe and Ni, the electrolyte (9%) and the plastic components (2%). Elemental quantitative analysis showed that the electrodes are highly concentrated in metals. The phase identification achieved by X-ray powder diffraction combined with chemical analysis and leaching tests allowed the authors to proceed with the composition of the electrode materials as following: cathode: 28.7% metallic Ni, 53.3% Ni(OH)2, 6.8% Cd(OH)2 and 2.8% Co(OH)2; anode: 39.4% metallic Ni and 57.0% Cd(OH)2. The morphology of the electrodes was studied by microscopic techniques and two phases were observed in the electrodes: (1) a bright metallic phase constituted of small nickel grains that acts as conductor, and (2) the main hydroxide phase of the active electrodes into which the nickel grains are dispersed. The disaggregation of the electrode particles from the supporting plates was easily obtained during the dismantling procedures, indicating that a substantial percentage of the electrodes can be efficiently separated by wet sieving after shredding the spent batteries.


Assuntos
Cádmio/química , Fontes de Energia Elétrica , Níquel/química , Eletrodos , Microscopia Eletrônica de Varredura , Espectrometria de Fluorescência , Propriedades de Superfície , Termogravimetria , Difração de Raios X
15.
J Med Virol ; 63(3): 237-41, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11170063

RESUMO

The incidence of GBV-C/hepatitis G virus (GBV-C/HGV) infection after blood transfusion is unknown in Brazil. Many studies have so far addressed its relationship with blood transfusion, but its association with liver disease was not confirmed. A prospective study was carried out between 1996 and 1999 in Rio de Janeiro. Ninety three patients who received blood transfusion during cardiac surgery were followed for six months and blood samples were drawn before and after surgery to determine antibodies to GBV-C/hepatitis G virus (anti-HGenv) using a step sandwich immunoassay and GBV-C/HGV-RNA using reverse transcriptase polymerase chain reaction. The alanine aminotransferase (ALT) levels were serially determined as well as clinical data compiled related to hepatitis. Prior to surgery, anti-HGenv was present in 35.5% (33/93) of patients and 4.3%(4/93) were found to be viremic. Seroconversion following transfusion was observed in 9 patients and 4 additional individuals became viremic for a total incidence of 23% (13/56). Six months after blood transfusion, only 4 of those nine patients previously antibody positive still had anti-HGenv detectable in serum. No patients had clinical or laboratory evidence of acute hepatitis and no correlation was found with GBV-C/HGV infection and number of blood units transfused (p = 0.37). This study highlights the importance of using both HGV-RNA PCR and anti-HGenv to accurately estimate the magnitude of GBV-C/HGV infection. The observed high prevalence and incidence rates show that this infection is common in Brazil; however, no clinical or biochemical evidence of liver disease was demonstrated in the period of study and longer longitudinal observation is needed to define any pathogenic effect.


Assuntos
Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Hepatite Viral Humana/epidemiologia , Hepatite Viral Humana/etiologia , Reação Transfusional , Adolescente , Adulto , Idoso , Brasil/epidemiologia , Estudos de Coortes , Feminino , Flaviviridae , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Prospectivos
16.
J Opt Soc Am A Opt Image Sci Vis ; 16(5): 953-78, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10234852

RESUMO

A neural model of motion perception simulates psychophysical data concerning first-order and second-order motion stimuli, including the reversal of perceived motion direction with distance from the stimulus (gamma display), and data about directional judgments as a function of relative spatial phase or spatial and temporal frequency. Many other second-order motion percepts that have ascribed to a second non-Fourier processing stream can also be explained in the model by interactions between ON and OFF cells within a single, neurobiologically interpreted magnocellular processing stream. Yet other percepts may be traced to interactions between form and motion processing streams, rather than to processing within multiple motion processing streams. The model hereby explains why monkeys with lesions of the parvocellular layers, but not of the magnocellular layers, of the lateral geniculate nucleus (LGN) are capable of detecting the correct direction of second-order motion, why most cells in area MT are sensitive to both first-order and second-order motion, and why after 2-amino-4-phosphonobutyrate injection selectively blocks retinal ON bipolar cells, cortical cells are sensitive only to the motion of a moving bright bar's trailing edge. Magnocellular LGN cells show relatively transient responses, whereas parvocellular LGN cells show relatively sustained responses. Correspondingly, the model bases its directional estimates on the outputs of model ON and OFF transient cells that are organized in opponent circuits wherein antagonistic rebounds occur in response to stimulus offset. Center-surround interactions convert these ON and OFF outputs into responses of lightening and darkening cells that are sensitive both to direct inputs and to rebound responses in their receptive field centers and surrounds. The total pattern of activity increments and decrements is used by subsequent processing stages (spatially short-range filters, competitive interactions, spatially long-range filters, and directional grouping cells) to determine the perceived direction of motion.


Assuntos
Corpos Geniculados/fisiologia , Modelos Neurológicos , Percepção de Movimento/fisiologia , Animais , Análise de Fourier , Corpos Geniculados/anatomia & histologia , Corpos Geniculados/lesões , Haplorrinos , Humanos , Matemática , Estimulação Luminosa , Psicofísica
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