RESUMO
We report experiments with polyaniline-Fe3O4 (PANI-Fe3O4) nanocomposites synthesized under several different conditions. With a reaction carried out at room temperature and assisted by intense ultra-violet (UV) irradiation, we observe sustained oscillations in the magnetization with a period of about 25 min. The oscillations are interpreted as the result of an oscillatory chemical reaction in which part of the Fe(+2) ions of magnetite, Fe3O4, are oxidized by the UV irradiation to form Fe(+3) so that a fraction of the magnetite content transforms into maghemite, γ-Fe2O3. Then, Fe(+3) ions at the nanoparticle surfaces are reduced and transformed back into Fe(+2), when acting as an oxidizing agent for polyaniline in the polymerization process. Since maghemite has smaller magnetization than magnetite, the oscillating chemical reaction results in the oscillatory magnetization. The observations are interpreted with the Lotka-Volterra nonlinear coupled equations with parameters that can be adjusted to fit very well the experimental data.
RESUMO
Fifty-three patients with hematological malignancies who underwent Allo-SCT from HLA-identical siblings were randomly assigned to receive glutamine-enriched parenteral nutrition-PN (GlPN, n=27) or standard PN (PN, n=26), in isonitrogenous solutions. Deaths (D+100 and D+180), infections, acute GVHD, length of stay, time of neutropenia and intestinal permeability (IP) were studied. Ages, gender, diagnosis, disease status and treatment variables were equally distributed between groups. Survival on D+180 was increased in GlPN (74%) vs PN (46%), P=0.03 (log-rank), as on D+100 (P=0.05). Most deaths occurred before D+100, especially in PN (10/26, 39%) vs GlPN (4/27, 15%). GVHD was the most frequent cause of death (8/21, 38%), especially in PN (n=6, five before D+100). Other outcomes were not affected. IP was affected on admission, was not affected by glutamine enrichment, but consistently worsened throughout the study. Results showed that GlPN was efficacious in increasing short-term survival after Allo-SCT. Benefits of glutamine seem to be independent of mucosal protection, as IP was not affected by its use. A trend to a lower incidence of GVHD deaths may suggest an immunomodulatory role of glutamine.
Assuntos
Suplementos Nutricionais , Glutamina , Transplante de Células-Tronco Hematopoéticas/métodos , Nutrição Parenteral Total/métodos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Sobrevida , Transplante HomólogoRESUMO
The effects of ultrasonic wave on the conducting polymer polyaniline dissolved in DMSO were observed. The UV-visible, infrared and NMR analysis show that the polymer undergo a redox and doping transition when the ultrasound wave interacts with the polymer dissolved into the solvent. The proposed mechanism to explain these effects is based on the solvent's hygroscopicity properties. The interaction with the ultrasonic wave, homolitically dissociates the water molecule producing radical species, and these species interact with the dissolved conducting polymer changing its oxidation and doped state. The resulting effects of that interaction are the modification of oxidation state of the conducting polymer and the decrease of the amount of water molecule in the solvent. From those results, we have proposed one straightforward method to eliminate water contamination in the solvent DMSO using ultrasonic waves.
Assuntos
Polímeros/química , Ultrassom , Compostos de Anilina/química , Química/métodos , Dimetil Sulfóxido/química , Espectroscopia de Ressonância Magnética/métodos , Modelos Químicos , Oxirredução , Oxigênio/metabolismo , Solventes/química , Espectrofotometria/métodos , Raios Ultravioleta , Água/químicaRESUMO
In this work we present the synthesis, characterisation and the thermoluminescence (TL) response of nanoporous carbon doped aluminium oxide Al2O3:C produced by anodic oxidation of aluminium in organic and inorganic solvents. The X-ray and scanning electron microscopy (SEM) measurements reveal that the synthesised samples are amorphous and present highly ordered structures with uniform pore distribution with diameter of the order 50 nm. The photoluminescence and spectroscopic analysis in the visible and infrared regions show that the luminescence properties presented by the samples prepared in organic acid are due to carboxylate species, incorporated in anodic alumina films during the synthesis process. After an annealing treatment, part of the incorporated species decomposes and is incorporated into the structure of the aluminium oxide yielding a highly thermoluminescent detector (TL) . The results for X-ray irradiation in the range from 21 to 80 keV indicate a linear TL response with the dose in the range from 5 mGy to 1 Gy, suggesting that nanoporous aluminium oxide produced in the present route of synthesis is a suitable detector for radiation measurements.
Assuntos
Óxido de Alumínio/química , Óxido de Alumínio/efeitos da radiação , Carbono/química , Nanoestruturas/química , Nanoestruturas/efeitos da radiação , Nanotecnologia/instrumentação , Dosimetria Termoluminescente/instrumentação , Carbono/efeitos da radiação , Relação Dose-Resposta à Radiação , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Tamanho da Partícula , Porosidade , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Dosimetria Termoluminescente/métodosRESUMO
The impurity-related point defects and the dosimetry properties of quartz irradiated with gamma- and X-rays doses were investigated for natural crystals taken from different geologies. The specimens were initially irradiated with gamma particles from (137)Cs to determine the sensitivity and repeatability of thermoluminescence (TL) emission at approximately 503 K. The dose response was investigated in the range 1-20 mGy. The energy dependence was considered in the range 16-65 keV with X rays and with gamma rays from 137Cs and 60Co. It was found that quartz material from two geologies exhibit a linear relationship between TL intensities and absorbed doses with high angular coefficients. Its sensitivities are higher than that found for LiF TLD-100 dosemeters irradiated in the same conditions. The results were discussed in relation to pre-existing impurity contents and the formation of Al-hole centres.
Assuntos
Cimentos de Resina/química , Cimentos de Resina/efeitos da radiação , Dosimetria Termoluminescente/métodos , Brasil , Relação Dose-Resposta à Radiação , Teste de Materiais , Doses de Radiação , Radiação Ionizante , Cimentos de Resina/análiseRESUMO
Allogeneic blood stem cell (BSC) transplantation has been performed experimentally in some patients with success. Wider application of this therapeutic modality has been hampered ultimately by many factors, mainly the concern that infusion of large numbers of donor T cells could result in an increased incidence and severity of graft-versus-host disease (GVHD). We report the short-term results of 17 allogeneic BSC transplants in patients with hematologic malignancies. When compared to standard BMT results, BSC transplants showed the advantages of faster engraftment, shorter hospital stay and fewer antibiotic needs. The incidence and severity of GVHD, as well as the general BMT-associated morbidity, was comparable between the two groups. BSC collection by apheresis was well tolerated and associated with less morbidity for donors, probably reducing the cost of the treatment. The collection of BSC was a single apheresis procedure and yielded adequate numbers of stem cells to ensure engraftment. Although this was not a prospective randomized study, the data obtained are encouraging and warrant more prospective and controlled studies.
Assuntos
Fator Estimulador de Colônias de Granulócitos/farmacologia , Transplante de Células-Tronco Hematopoéticas , Leucemia/terapia , Doença Aguda , Adolescente , Adulto , Separação Celular , Feminino , Doença Enxerto-Hospedeiro/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Proteínas Recombinantes/farmacologia , Transplante HomólogoRESUMO
We present the results of a prospective, randomised study comparing PBPC and BM focusing on engraftment, acute and chronic GVHD and survival. Forty patients with haematological malignancies received HLA-identical sibling BM (group A) or PBPC (group B). Evaluable patients were 19 (A) and 18 (B). Median age was 35 (17-56) in A and 29.5 (9-51) in B. Conditioning was mainly Bu-Cy2; GVHD prophylaxis was CSA-MTX. PBPC were harvested after 5 days of G-CSF 10 microg/kg/day. Median days for an ANC >0.5 x 10(9)/l was 18 (13-30) in A and 16 (11-25) in B (P = 0.10). Platelets >20 x 10(9)/l occurred at +17 (10-40) in A and +12 (9-36) in B (P = 0.01). The probability of > or =2 grade a-GVHD was 19% (A) and 27% (B) (P = 0.53). The probability of all grade c-GVHD was 70% with BM. In spite of the small number of patients in group B (PBPC), our data suggest the great majority of them will have c-GVHD (P = 0.08); extensive disease was present in 50 and 100%, respectively (P = 0.05). The estimates of overall survival for A and B at 1000 days are 51 and 47%, respectively (P = 0.67); DFS at 1000 days are 52 and 58%, respectively (P = 0.50). PBPC resulted in faster platelet engraftment. The incidence of acute and chronic GVHD was similar in both groups, but the severity of c-GVHD was higher with PBPC. No differences in survival and DFS have been observed to date.
Assuntos
Transplante de Medula Óssea , Neoplasias Hematológicas/terapia , Transplante de Células-Tronco Hematopoéticas , Adolescente , Adulto , Transplante de Medula Óssea/efeitos adversos , Criança , Feminino , Sobrevivência de Enxerto , Doença Enxerto-Hospedeiro/etiologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Análise de Sobrevida , Transplante HomólogoRESUMO
We developed an efficient method to prepare a hybrid inorganic-organic composite based on polyvinyl alcohol (PVA) and polysiloxane using the sol-gel disc technique. Antigen obtained from Yersinia pestis was covalently immobilized onto these discs with glutaraldehyde and used as solid phase in ELISA for antibody detection in serum of rabbits experimentally immunized with plague. Using 1.25 microg antigen per disc, a peroxidase conjugate dilution of 1:4,000 and a serum dilution of 1:200 were adequate for the establishment of the procedure. These values are similar to those used for PVA-glutaraldehyde discs, plasticized filter paper discs and the polyaniline-Dacron composite discs. This procedure is comparable to that which utilizes the adsorption of the antigen to conventional PVC plates, with the amount of antigen being one fourth that employed in conventional PVC plates (5 microg/well). In addition to the performance of the polysiloxane/PVA-glutaraldehyde disc as a matrix for immunodetection, its easy synthesis and low cost are additional advantages for commercial application.
Assuntos
Antígenos de Bactérias/isolamento & purificação , Ensaio de Imunoadsorção Enzimática/métodos , Álcool de Polivinil/química , Siloxanas/química , Yersinia/imunologia , Animais , Ensaio de Imunoadsorção Enzimática/instrumentação , Fixadores , Glutaral , CoelhosRESUMO
A polyaniline silicone support to immobilize xanthine oxidase is proposed as a reactor coil to monitor the action of xanthine oxidase on hypoxanthine, xanthine and 6-mercaptopurine. A purified xanthine oxidase immobilized on this support lost 80% of the initial activity after 12 min of use. Co-immobilization of superoxide dismutase and catalase increased the stability of immobilized xanthine oxidase so that the derivative maintained 79% of its initial activity after 4.6 h of continuous use in which 1.5 mumol purine bases were converted by the immobilized enzyme system. There is no evidence of either polyaniline or protein leaching from the coil during 3 h of continuous use. When solutions (10 ml) of hypoxanthine, xanthine and 6-mercaptopurine were circulated individually through the xanthine oxidase-superoxide dismutase-catalase-polyaniline coil (1 mm internal diameter and 3 m in length, 3 ml internal volume) activities of 8.12, 11.17 and 1.09 nmol min-1 coil-1, respectively, were obtained. The advantages of the reactor configuration and the redox properties of the polymer, particularly with respect to immobilized oxidoreductases, make this methodology attractive for similar enzyme systems. This immobilized enzyme system using polyaniline-silicone as support converted 6-mercaptopurine to 6-thiouric acid with equal efficiency as resins based on polyacrylamide and polyamide 11.
Assuntos
Xantina Oxidase/metabolismo , Enzimas Imobilizadas/metabolismo , Técnicas In Vitro , SiliconesRESUMO
OBJECTIVE: This study was conducted to compare the survival rates of bone marrow transplantation (BMT) patients who were affected with the survival rates of those who were not affected by oral recrudescent human herpes virus-1 infection (HHV-1) after transplantation. STUDY DESIGN: Fifty-two consecutive patients who underwent BMT were included in the study. The time of death after BMT was displayed, by means of the Kaplan-Meier method, for the following parameters: age and gender of the patient, donor gender, primary disease, stem cells, conditioning regimen, platelet number after day 100, acute and chronic graft-versus-host disease, oral recurrent HHV-1 infection post-BMT, oral lichenoid lesions of graft-versus-host disease, graft-versus-host disease at the salivary glands, parenteral nutrition, and oral mucositis. The data were initially analyzed by means of the log-rank test and then included in the Cox proportional hazards model. RESULTS: The multivariate analysis demonstrated a significance of 5% for only the platelet numbers and oral recurrent HHV-1 infection. CONCLUSION: The present study provides evidence that platelet numbers below 100,000 cells/mm(3) after day 100 and oral recurrent HHV-1 infection are independent negative prognostic variables in BMT patients' 24-month survival rates.
Assuntos
Transplante de Medula Óssea , Estomatite Herpética/etiologia , Doença Aguda , Aciclovir/uso terapêutico , Adolescente , Adulto , Fatores Etários , Anemia Aplástica/terapia , Antivirais/uso terapêutico , Doença Crônica , Feminino , Doença Enxerto-Hospedeiro/etiologia , Humanos , Leucemia/terapia , Modelos Lineares , Linfoma/terapia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Contagem de Plaquetas , Prognóstico , Modelos de Riscos Proporcionais , Recidiva , Doenças das Glândulas Salivares/etiologia , Fatores Sexuais , Estomatite/etiologia , Estomatite Herpética/tratamento farmacológico , Estomatite Herpética/prevenção & controle , Taxa de Sobrevida , Doadores de Tecidos , Condicionamento Pré-TransplanteRESUMO
A biosensor for glucose utilizing kinetics of glucose oxidase (EC 1.1.3.4.) was developed. The enzyme was immobilized on polyaniline by covalent bonding, using glutaraldehyde as a bifunctional agent. The system showed a linear response up to 2.2 mM of glucose with a response time of 2.5-4.0 min. In addition, the immobilized enzyme had a higher activity between pH 6.5 and 7.5. The system retained 50% of its activity after 30 d of daily use. The optical absorption spectra of the polyaniline/glucose oxidase electrode after glucose had been added to the buffer solution showed that the absorption band around 800 nm had changed considerably when glucose was allowed to react with the electrode. This optical variation makes polyaniline a very promising polymer for use as a support in optical sensor for clinical application.
Assuntos
Compostos de Anilina , Técnicas Biossensoriais , Enzimas Imobilizadas , Glucose Oxidase/metabolismo , Glucose/análise , Soluções Tampão , Glutaral , PolímerosRESUMO
Soluble adult Schistosoma mansoni antigen preparation (SWAP) was covalently fixed onto polyvinyl alcohol-glutaraldehyde discs and an enzyme linked-immunosorbent assay (ELISA) was set up. The best conditions for the assay were established and it was found that small amount of antigen such as 1.5 micrograms was required. A comparison between this procedure and the conventional ELISA was proceeded. A reliable method of antigen immobilization was achieved and the low prices of the employed reagents are economically attractive.
Assuntos
Glutaral , Álcool de Polivinil , Esquistossomose/diagnóstico , Animais , Ensaio de Imunoadsorção Enzimática , Humanos , CoelhosRESUMO
In this work we discuss the synthesis, characterization and the use of rare earth doped silica glass prepared by the sol-gel technique as a gamma radiation detector. We obtain a glass material doped with rare earth ions in a high local symmetry, in contrast to the low symmetry found in glasses produced by conventional melting methods and technologies. The behavior of the luminescence spectra of the excited states of rare earth indicates a strong dependence with gamma radiation doses, where the magnetic dipole transition 5D0-->7F1 of the Eu3+ ions presents an huge enhancement of 900% for irradiation doses up to 400 Gy.
RESUMO
In this work, alternative heterojunction devices to be used for gamma-radiation detection are presented. The high quality silicon/polyaniline heterostructures use polyaniline thin films as an active part of the device structure. Polyaniline thin films 40 nm thick were deposited onto silicon substrates (n-type, <100>, 1 ohm x cm) using the spin-coating technique from soluble polyaniline. The devices present excellent electrical characteristics, with a rectification ratio of 60,000 at +/- 1.0 V, reverse currents in the order of a few nA and ideality factor approximately 2. These electrical characteristics indicate great potential for their use in sensor applications. The heterojunction diode is very sensitive to gamma radiation in the dose range of 0-7000 Gy, presenting a linear response in the forward and reverse bias. The excellent electrical characteristics, together with the linear response with the dose strongly suggest the application of this device for spectrometry or dosimetry of low and high doses of gamma ray radiation.
Assuntos
Raios gama , Radiometria/métodos , Silício , Polímeros , Doses de Radiação , Radiometria/instrumentaçãoAssuntos
Fator Estimulador de Colônias de Granulócitos/farmacologia , Transplante de Células-Tronco Hematopoéticas , Transtornos Imunoproliferativos/terapia , Transplante de Medula Óssea , Doença Enxerto-Hospedeiro/etiologia , Fator Estimulador de Colônias de Granulócitos/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Contagem de Linfócitos/efeitos dos fármacos , Avaliação de Processos e Resultados em Cuidados de Saúde , Transplante HomólogoRESUMO
Polyaniline (PANI) was chemically synthesized on a dacron disk surface and an antigen (F1 fraction) obtained from Yersinia pestis was covalently fixed onto this composite via glutaraldehyde. The enzyme linked immunosorbent assay (ELISA) or rapid ELISA procedure detected immunoglobulin G (IgG) anti-F1 fraction in human serum employing this derivative. The appropriate conditions for carrying out the test were established as an antigen concentration of 2 microg/PANI-dacron disk, peroxidase labeled goat anti-human IgG conjugate diluted 4000 times, and a serum dilution of 1:100. The PANI-dacron disks showed greater antigen retention than conventional poly(vinyl chloride) plates and less antibody unspecific adsorption.
Assuntos
Compostos de Anilina , Anticorpos Antibacterianos/análise , Proteínas de Bactérias/imunologia , Ensaio de Imunoadsorção Enzimática , Peste/imunologia , Polietilenotereftalatos , Yersinia pestis/imunologia , Compostos de Anilina/síntese química , Compostos de Anilina/química , Proteínas de Bactérias/sangue , Materiais Revestidos Biocompatíveis , Estabilidade de Medicamentos , Resinas Epóxi , Humanos , Polietilenotereftalatos/química , Polietilenos , Fatores de TempoRESUMO
The nonlinear-optical properties of a semi-interpenetrating polymer network of poly(vinyl alcohol) glutaralde-hyde-polyaniline were studied. Large (>/=10(-12) cm(2)/W) and fast (<50 ps) refractive optical nonlinearites were observed. The potential of this novel material for photonic applications is evaluated.
RESUMO
Antigen from Yersinia pestis was adsorbed on cellulose acetate discs (0.5 cm of diameter) which were obtained from dialysis membrane by using a paper punch. ELISA for human plague diagnosis was carried out employing this matrix and was capable to detect amount of 1.3 microg of antigen, 3,200 times diluted positive serum using human anti-IgG conjugate diluted 1:4,000. No relevant antigen lixiviation from the cellulose acetate was observed even after washing the discs 15 times. The discs were impregnated by the coloured products from the ELISA development allowing its use in dot-ELISA. Furthermore, cellulose acetate showed a better performance than the conventional PVC plates.
Assuntos
Antígenos de Bactérias/isolamento & purificação , Celulose , Ensaio de Imunoadsorção Enzimática/métodos , Peste/imunologia , Yersinia pestis/imunologia , Humanos , Imunoglobulina G/isolamento & purificação , TitulometriaRESUMO
BACKGROUND: PBSC transplant provides 10 times more T cells than BMT However, the incidence and severity of acute GvHD is similar among recipients of both types of transplants. Studies in mouse models suggest that the similar clinical outcome in BMT and PBSCT is due to differences in the lymphokine profiles. METHODS: PBMC, PBMC from G-CSF mobilized donors (G-PBMC)and BM mononuclear cells (BM-MC) were analyzed by flow cytometry and ELISA to detect gamma-IFN and IL-4 production. Hematoxylin and eosin staining was used to identify morphology and annexin/propidium-iodide was used for apoptosis assays. RESULTS: We show decreased production of gamma-interferon (85%) and IL-4 (60%) in G-PBMC when compared with either PBMC or BM-MCT cells on ex vivo assays. Surprisingly, 85% of fresh G-PBMC is composed of low-density granulocytes (LDG), which undergo apoptosis after 48 h in culture. At this same time, gamma-IFN production from G-PBMC T cell was reverted. In vitro, G-CSF converts granulocytes into LDGs, able to inhibit T-cell function by H2O2 production, and not through immune-deviation towards a Th2-type phenotype. DISCUSSION: We show that the estimated numbers of Th1 and Th2 cells infused in BMT and PBSCT do not differ significantly. These findings are discussed with reference to the relatively low incidence of acute GvHD in PBSCT shown in the literature. We suggest that these results might depend on the high number of granulocytes and progenitors infused. The potential use of granulocytes as immunosupressive short-term therapy is now being investigated by our group using a mouse experimental model.
Assuntos
Granulócitos/fisiologia , Transplante de Células-Tronco de Sangue Periférico , Linfócitos T/fisiologia , Acetato de Tetradecanoilforbol/análogos & derivados , Anexina A5/análise , Antígenos CD/análise , Apoptose/fisiologia , Células da Medula Óssea/citologia , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/fisiologia , Transplante de Medula Óssea , Complexo CD3/análise , Catalase/farmacologia , Contagem de Células , Citometria de Fluxo , Fator Estimulador de Colônias de Granulócitos/farmacologia , Granulócitos/citologia , Granulócitos/efeitos dos fármacos , Mobilização de Células-Tronco Hematopoéticas , Transplante de Células-Tronco Hematopoéticas , Humanos , Peróxido de Hidrogênio/metabolismo , Interferon gama/análise , Interleucina-4/análise , Ionomicina/farmacologia , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/fisiologia , Leucossialina , Teste de Cultura Mista de Linfócitos , Ativação de Neutrófilo/efeitos dos fármacos , Ativação de Neutrófilo/fisiologia , Sialoglicoproteínas/análise , Linfócitos T/química , Linfócitos T/efeitos dos fármacos , Acetato de Tetradecanoilforbol/farmacologia , Fatores de TempoRESUMO
We developed an efficient method to prepare a hybrid inorganic-organic composite based on polyvinyl alcohol (PVA) and polysiloxane using the sol-gel disc technique. Antigen obtained from Yersinia pestis was covalently immobilized onto these discs with glutaraldehyde and used as solid phase in ELISA for antibody detection in serum of rabbits experimentally immunized with plague. Using 1.25 æg antigen per disc, a peroxidase conjugate dilution of 1:4,000 and a serum dilution of 1:200 were adequate for the establishment of the procedure. These values are similar to those used for PVA-glutaraldehyde discs, plasticized filter paper discs and the polyaniline-Dacron composite discs. This procedure is comparable to that which utilizes the adsorption of the antigen to conventional PVC plates, with the amount of antigen being one fourth that employed in conventional PVC plates (5 æg/well). In addition to the performance of the polysiloxane/PVA-glutaraldehyde disc as a matrix for immunodetection, its easy synthesis and low cost are additional advantages for commercial application