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1.
Genet Mol Res ; 12(4): 4855-68, 2013 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-24301747

RESUMO

TcPR-10, a member of the pathogenesis-related protein 10 family, was identified in EST library of interactions between Theobroma cacao and Moniliophthora perniciosa. TcPR-10 has been shown to have antifungal and ribonuclease activities in vitro. This study aimed to identify proteins that are differentially expressed in M. perniciosa in response to TcPR-10 through a proteomic analysis. The fungal hyphae were subjected to one of four treatments: control treatment or 30-, 60- or 120-min treatment with the TcPR-10 protein. Two-dimensional maps revealed 191 differentially expressed proteins, 55 of which were identified by mass spectrometry. The proteins identified in all treatments were divided into the following classes: cell metabolism, stress response, zinc binding, phosphorylation mechanism, transport, autophagy, DNA repair, and oxidoreductases. The predominant class was stress-response proteins (29%), such as heat shock proteins; these proteins exhibited the highest expression levels relative to the control treatment and are known to trigger defense mechanisms against cytotoxic drugs as well as TcPR-10. Oxidoreductases (25%) were overexpressed in the control and in 30-min treatments but exhibited reduced expression at 120 min. These proteins are involved in the repair of damage caused by oxidative stress due to the contact with TcPR- 10. Consistent with the antifungal activity of TcPR-10, several proteins identified were related to detoxification, autophagy or were involved in mechanisms for maintaining fungal homeostasis, such as ergosterol biosynthesis. These results show that the sensitivity of the fungus to TcPR-10 involves several biochemical routes, clarifying the possible modes of action of this antifungal protein.


Assuntos
Basidiomycota/efeitos dos fármacos , Basidiomycota/metabolismo , Cacau/química , Proteínas Fúngicas/metabolismo , Proteínas de Plantas/farmacologia , Proteoma , Proteômica , Basidiomycota/genética , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Proteômica/métodos , Estresse Fisiológico , Fatores de Tempo
2.
J Prim Health Care ; 15(4): 366-375, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38112707

RESUMO

Introduction Key New Zealand ethical documents that describe appropriate ethical behaviour for doctors do not consider rurality and how this might impact on the practice of medicine. Aim The aim of this study was to understand the literature on key ethical issues experienced by general practitioners in a rural context that might inform the development of a New Zealand agenda of rural medical ethics Methods A rapid review was undertaken of three databases using a variety of key words relating to rurality, ethics, professionalism and medicine. Inclusion criteria were research articles focussing on the experience of doctors working in a rural healthcare setting, commentaries and narratives. The findings from the paper were synthesised and broad ethical categories created. Results Twelve studies were identified that met the inclusion and exclusion criteria. Synthesis of the data revealed five ethical issues that predominately arose from living and working within communities. These ethical issues related to juggling personal and professional lives, managing friendships with patients, managing loss of privacy and anonymity, assuring confidentiality and practicing outside of comfort zones. Discussion The majority of ethical issues arose from managing overlapping relationships. However, these overlapping relationships and roles are considered normal in rural settings. A tension is created between adhering to urban normative ethical guidelines and the reality of living in a rural environment. Professional ethical guidelines, such as those developed by the New Zealand Medical Council, do not account for this rural lived reality. Rural practitioners in New Zealand should be engaged with to progress a specific rural ethics agenda.


Assuntos
Confidencialidade , Medicina Geral , Humanos , Medicina de Família e Comunidade , População Rural , Nova Zelândia
3.
Pharmaceuticals (Basel) ; 16(5)2023 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-37242472

RESUMO

Margaritaria nobilis L.f. (Phyllanthaceae), a native Brazilian tree occurring mainly in the Amazon, is used in folk medicine for the treatment of abscesses (bark) and cancer-like symptoms (leaves). The present study evaluates the safety of its acute oral administration and its effects on nociception and plasma leakage. The chemical constitution of the leaf's ethanolic extract is determined by ultra-performance liquid chromatography-high-resolution mass spectrometry (LC-MS. Its acute oral toxicity is evaluated in female rats at a dose of 2000 mg/kg, evaluating the occurrence of deaths and Hippocratic, behavioral, hematological, biochemical, and histopathological changes, as well as food and water consumption and weight gain. Antinociceptive activity is evaluated in male mice with acetic-acid-induced peritonitis (APT) and formalin (FT) tests. An open field (OF) test is performed to verify possible interferences in the animals' consciousness or locomotion. LC-MS analysis shows the presence of 44 compounds classified as phenolic acid derivatives, flavonoids and O-glycosylated derivatives, and hydrolyzable tannins. No deaths or significant behavioral, histological, or biochemical changes are observed in the toxicity assessment. In nociception tests, M. nobilis extract significantly reduces abdominal contortions in APT, demonstrating selectivity for inflammatory components (FT second phase), not interfering in neuropathic components (FT first phase) or consciousness and locomotion levels in OF. Additionally, M. nobilis extract inhibits plasma acetic-acid-induced leakage. These data demonstrate the low toxicity of M. nobilis ethanolic extract, as well as its effectiveness in modulating inflammatory nociception and plasma leakage, possibly related to the flavonoids and tannins present in its composition.

4.
Trans R Soc Trop Med Hyg ; 116(2): 108-116, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34134133

RESUMO

BACKGROUND: We analysed the spatial distribution and the socio-economic and environmental factors (SEFs) associated with Schistosoma mansoni infection in the state of Alagoas, an important tourist area in northeastern Brazil. METHODS: We conducted an ecological time-series study (2007-2016) on schistosomiasis cases and SEFs. We evaluated the temporal trends of schistosomiasis cases (annual percentage change [APC]) and their correlation with SEFs. Spatial analysis maps were built using QGIS and TerraView software. RESULTS: We observed that 4.9% of the municipalities had a high prevalence of S. mansoni infection and were located mainly in the coastal strip of Alagoas state. The positivity rate for schistosomiasis decreased during the period (8.1% in 2007 to 4.9% in 2016; APC=-5.71). There was a reduction in the number of tests performed (APC=-5.05). There was a negative correlation between S. mansoni infection and the municipal human development index (ρ=-0.34) and schooling rate (ρ=-0.24). The main species of snail was Biomphalaria glabrata (94.79%), but Biomphalaria straminea showed a higher percentage of S. mansoni detection (10.11%). Lastly, Biomphalaria tenagophila specimens were identified for the first time in Alagoas (n=28). CONCLUSIONS: Despite a reduction in the number of cases, intestinal schistosomiasis still represents a serious public health concern in Alagoas. It urgently requires planning and improvements in diagnosis, prevention programs and the state's socio-economic indicators.


Assuntos
Biomphalaria , Esquistossomose mansoni , Esquistossomose , Animais , Brasil/epidemiologia , Vetores de Doenças , Humanos , Schistosoma mansoni , Esquistossomose mansoni/diagnóstico , Esquistossomose mansoni/epidemiologia , Fatores Socioeconômicos
5.
Med Sci Law ; 50(3): 126-30, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21133262

RESUMO

AIM: The aim of this study was to examine the similarities and differences between matricide and patricide committed by mentally disordered offenders in Zimbabwe. METHODS: A comprehensive, retrospective and national study was carried out of all individuals in Zimbabwe who, between 1980 and 1990 inclusive, were charged with homicide of their biological parents. The data were obtained from a hospital-wide survey, in a written semistructured format. RESULTS: The sample size was 39 offenders (34 men, 5 women) and there were 39 victims (20 matricides and 19 patricides). Sons committed 18 patricides and 16 matricides, and daughters committed one patricide and four matricides. The mean age of the offenders was 35 years with a standard deviation of 9.8, and the mean age of the victims was 60 years with a standard deviation of 9.3. Ethnicity of all the offenders and their victims was African. About one-third of the offenders were known to the psychiatric services and the rest were found to be mentally ill at the time of the crime when they were tried in the court of law. Most of the offenders were suffering from a psychotic illness and one offender had a diagnosis of personality disorder. Half of the offenders had been to a traditional healer some time before committing the crime. Most of the offenders used a blunt instrument, 15 used sharp instruments and one woman used strangulation. Firearms were not used in committing parricide. CONCLUSION: The study showed that sons committed most parricides. However, daughters committed matricide more frequently than patricide. Male offenders were 10 years younger than female offenders. In all cases both the offender and victim were African, and lived in the same house in the rural areas of Zimbabwe. Psychosis among the offenders had substantially increased the risk of parricide.


Assuntos
Homicídio/estatística & dados numéricos , Pessoas Mentalmente Doentes/estatística & dados numéricos , Pais , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Armas/estatística & dados numéricos , Adulto Jovem , Zimbábue/epidemiologia
6.
Science ; 196(4294): 1097-9, 1977 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-17778547

RESUMO

The semiconductor liquid junction cell n-GaAs/0.8M K(2)Se-0.1M K(2)Se(2)-1M KOH/C has been shown to attain 9 percent photovoltaic power conversion efficiency in sunlight. Accelerated tests under 3100 degrees K light sources of several solar intensities indicate very low photocorrosion currents and high output stability.

7.
Med Sci Law ; 47(3): 253-61, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17725240

RESUMO

Our aim was to compare socio-demographic, clinical and criminal characteristics of mentally disordered offender patients in a special institution in a developing and a developed country. Zimbabwe data from 1980-1990 was obtained from a hospital patient survey, in a written semistructured format. The English special (high security) hospital patients' data for the same period was obtained from the case register. The sample size for Zimbabwe was 367 patients (337 males, 30 females) and for England and Wales it was 1,966 patients (1,643 males, 323 females). The average age for Zimbabwean patients was 36 years, with standard deviation of 9.7; for England and Wales the average age was 29.7 with standard deviation of 9.6. There was significant difference in marital status in the two countries. Seventy-eight per cent of patients were single in England and Wales, compared with 49% in Zimbabwe. There were 20% illiterate patients in Zimbabwe, compared with 4% in England and Wales. Thirty-seven per cent of the patients in England and Wales had a diagnosis of personality disorder, compared with 6% in Zimbabwe. There were 53% of homicides in Zimbabwe, compared with 20% in England and Wales. Employment in the two countries was similar: 34% in Zimbabwe and 33% in England and Wales. There were differences in the socio-demographic characteristics in the two countries, except for employment status. Differences were also noticed in the diagnoses of the patients, types of crime and the methods of assault.


Assuntos
Psiquiatria Legal , Transtornos Mentais , Pacientes/psicologia , Classe Social , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Inglaterra , Feminino , Humanos , Masculino , Transtornos Mentais/diagnóstico , Transtornos Mentais/fisiopatologia , Pessoa de Meia-Idade , País de Gales , Zimbábue
8.
J Mol Biol ; 233(4): 567-79, 1993 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-8411165

RESUMO

Mutations in Zn(2+)-coordinating histidine residues have been used to generate forms of transcription factor IIIA containing structural disruptions in single zinc fingers. These mutant proteins have been analyzed with respect to the structural and functional independence of individual zinc fingers in TFIIIA. They have also been used to assess the energetic contributions to binding and the sites of interaction of each of the nine zinc fingers of TFIIIA with the 5 S rRNA gene. The results are surprising and suggest a complex mode of binding in which the interactions of structurally independent zinc fingers with the DNA substrate are non-uniform and functionally interdependent in a way that may help to explain some of the unusual properties of TFIIIA.


Assuntos
DNA/metabolismo , Fatores de Transcrição/metabolismo , Dedos de Zinco , Animais , Sequência de Bases , Eletroforese em Gel de Poliacrilamida , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Relação Estrutura-Atividade , Termodinâmica , Fator de Transcrição TFIIIA , Fatores de Transcrição/química , Fatores de Transcrição/genética , Xenopus
9.
Rev Port Pneumol (2006) ; 21(4): 198-202, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25926243

RESUMO

BACKGROUND: As there are few studies on the impact of respiratory and functional status on the quality of life domains in adults with cystic fibrosis, this study aimed to evaluate the association between respiratory function, functional capacity and quality of life in these subjects. METHODS: This is a cross-sectional study, where adults with clinical and laboratorial diagnoses of CF fibrosis underwent pulmonary function tests, the six-minute walk distance test (6MWT) and responded to the Cystic Fibrosis Questionnaire-Revised (CFQ-R). Descriptive statistics was used to summarize the findings. The associations were tested by means of Pearson's or Spearman tests, and the significance level was set at 5%. RESULTS: The 21 patients who completed the study presented with reduced quality of life in all CFQ-R domains, obstructive pulmonary disease and reduced 6MWT distance. The following associations were found between pulmonary function and CFQ-R domains: forced vital capacity - FVC (%) and treatment burden and digestive symptoms (r=-0.433, p<0.05; r=-0.443, p<0.05, respectively), forced expiratory volume in one second - FVC ratio - FEV1/FVC (%) and physical functioning, social and respiratory symptoms (r=0.5, p<0.05; r=0.58, p<0.01; r=0.45, p<0.05, respectively), residual volume (%) and physical functioning (r=0.49, p<0.05), airways' resistance - Raw and physical functioning and emotional functioning (r=-0.44, p<0.05; r=-0,46, p<0.05, respectively), carbon monoxide diffusing capacity (%pred) and physical functioning (r=-0,51; p<0.05). CONCLUSION: Adults with CF have reduced quality of life, which in part is associated with the severity of their lung function.


Assuntos
Fibrose Cística/fisiopatologia , Pulmão/fisiopatologia , Qualidade de Vida , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Testes de Função Respiratória
10.
J Invest Dermatol ; 111(4): 629-33, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9764844

RESUMO

The sun is the most important and universal source of non-ionizing radiation shed on human populations. Life evolved on Earth bathed by this radiation. Solar UV damages cells, leading to deleterious conditions such as photoaging and carcinogenesis in human skin. During the process of evolution, the cells selected dark- and light-dependent repair mechanisms as a defence against these hazardous effects. This study describes the induction by non-coherent infrared radiation (700-2000 nm), in the absence of rising temperature, of a strong cellular defense against solar UV cytotoxicity as well as induction of cell mitosis. Blocking mitoses with arabinoside-cytosine or protein synthesis with cycloheximide did not abolish the protection, leading to the conclusion that this protection is independent of cell division and of protein neosynthesis. The protection provided by infrared radiation against solar UV radiation is shown to be a long-lasting (at least 24 h) and cumulatif phenomenon. Infrared radiation does not protect the lipids in cellular membranes against UVA induced peroxidation. The protection is not mediated by heat shock proteins. Living organisms on the Earth's surface are bathed by infrared radiation every day, before being submitted to solar UV. Thus, we propose that this as yet undescribed natural process of cell protection against solar UV, acquired and preserved through evolutional selection, plays an important role in life maintenance. Understanding and controlling this mechanism could provide important keys to the prevention of solar UV damage of human skin.


Assuntos
Fibroblastos/efeitos da radiação , Raios Infravermelhos , Raios Ultravioleta/efeitos adversos , Células Cultivadas , Cicloeximida/farmacologia , Feminino , Humanos , Lipídeos de Membrana/metabolismo , Lipídeos de Membrana/efeitos da radiação , Mitose/efeitos da radiação , Peróxidos/metabolismo , Biossíntese de Proteínas , Pele/citologia , Pele/efeitos da radiação
11.
Chest ; 117(5): 1443-8, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10807835

RESUMO

OBJECTIVE: Diaphragmatic reconstruction may cause several respiratory changes. The aims of the present study were to evaluate the respiratory changes induced by two methods of diaphragmatic reconstruction. METHODS: Two groups of rats with an experimental diaphragmatic defect were studied. In one group (n = 5), diaphragmatic resection was followed by stitching together the borders of the wound (SUT); in another group (n = 5), the defect was repaired by suturing in a polytetrafluoroethylene (PTFE) patch. All animals were sedated, anesthetized, paralyzed, and mechanically ventilated. Spirometry, respiratory mechanics, and thoracoabdominal morphometry were evaluated before and after diaphragmatic reconstruction. RESULTS: The suture of the diaphragm significantly decreased FVC and FEV(1), and increased respiratory system, lung, and chest wall static and dynamic elastances and viscoelastic/inhomogeneous pressures in relation to their respective control values. On the other hand, diaphragmatic reconstruction with PTFE increased only respiratory system, lung, and chest wall static elastances. In addition, respiratory system, pulmonary, and chest wall viscoelastic/inhomogeneous pressures and dynamic elastances, as well as respiratory system and lung elastances, were significantly greater in SUT than in PTFE. Lateral diameter at the level of the xiphoid and cephalocaudal pulmonary diameter diminished only in the SUT group. CONCLUSIONS: The reconstruction of the diaphragm with PTFE might be preferred to simple suture for surgical repair of large diaphragmatic defects, at least from a mechanical standpoint.


Assuntos
Diafragma/cirurgia , Politetrafluoretileno , Complicações Pós-Operatórias/etiologia , Implantação de Prótese , Insuficiência Respiratória/etiologia , Técnicas de Sutura , Animais , Diafragma/fisiopatologia , Elasticidade , Volume Expiratório Forçado/fisiologia , Medidas de Volume Pulmonar , Masculino , Complicações Pós-Operatórias/fisiopatologia , Ratos , Ratos Wistar , Insuficiência Respiratória/fisiopatologia , Mecânica Respiratória/fisiologia , Capacidade Vital
12.
Chest ; 113(6): 1667-72, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9631809

RESUMO

OBJECTIVE: Prosthetic reconstruction of the chest wall may yield several respiratory changes. Nevertheless, to our knowledge, no comprehensive analysis of respiratory mechanics under this condition has been hitherto performed. METHODS: Respiratory mechanics were evaluated in two groups of rats. In one group (n=8), a polytetrafluoroethylene (PTFE) patch was used; in another group (n=8), a polypropylene mesh (Marlex) associated with methylmethacrylate (PPMM) was employed. All animals were sedated, anesthetized, paralyzed, and mechanically ventilated before and after the prosthetic reconstruction of the chest wall. After airway occlusion at end inspiration, respiratory system, pulmonary, and chest wall resistive pressures (deltaP1rs, deltaP1L, and deltaP1cw, respectively) and viscoelastic/inhomogeneous pressures (deltaP2rs, deltaP2L, and deltaP2cw, respectively) were determined. Respiratory system, lung, and chest wall static (Est(rs), EstL, and Est(cw), respectively), and dynamic elastances (Edyn(rs), EdynL, and Edyn(cw), respectively), and the corresponding delta elastances (deltaE, calculated as Edyn-Est) were also obtained. RESULTS: In both groups, significant increases in deltaP2rs, deltaP2cw, deltaErs, deltaEcw, Est(rs), EstL, and Est(cw) were observed after chest wall reconstruction. However, deltaP2rs, deltaP2cw, deltaErs, deltaEcw, Est(rs), and EstL were significantly higher in the PPMM group than in the PTFE group. CONCLUSIONS: Prosthetic reconstruction of the chest wall yields not only elastic changes, but also there is also an important increase of pressure dissipated against viscoelastic/inhomogeneous segments of the chest wall. Furthermore, taking into account respiratory mechanics, the PTFE patch might be preferred to the PPMM patch.


Assuntos
Implantação de Prótese , Mecânica Respiratória , Procedimentos Cirúrgicos Torácicos , Animais , Materiais Biocompatíveis , Elasticidade , Masculino , Polietilenos , Polipropilenos , Politetrafluoretileno , Pressão , Ratos , Ratos Wistar , Telas Cirúrgicas , Tórax/fisiologia
13.
Photochem Photobiol ; 64(3): 542-6, 1996 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8806230

RESUMO

Light emitted by electronic photographic flash units is shown to damage bacteria and human skin fibroblasts deficient in repair systems, with survival curves very similar to those produced by 254 nm short UV. The lesions induced by these flashes are as photorepairable by the photolyase enzyme as those induced by 254 nm UV and result in equivalent survival rates. Biological dosimetry performed with microorganisms highly sensitive to UV (Escherichia coli K12 AB2480, deficient in excision and recombinational-dependent repair systems and Bacillus subtilis UVSSP spores, deficient in excision and in a specific spore repair process) revealed that each 1 ms flash of light from the photographic unit used in this work contained the equivalent of 0.25 J m-2 of 254 nm UV, when measured at a distance of 7.0 cm. This dose of UV was found to be lethal to both repair-deficient E. coli bacteria and repair-deficient human skin fibroblasts obtained from xeroderma pigmentosum donors, as well as mutagenic in B/r wild-type and HCR-mutant bacteria.


Assuntos
Fotografação , Transtornos de Fotossensibilidade/etiologia , Raios Ultravioleta/efeitos adversos , Bacillus subtilis/efeitos da radiação , Linhagem Celular , Escherichia coli/efeitos da radiação , Humanos , Mutação , Pele/efeitos da radiação , Xeroderma Pigmentoso/etiologia
14.
Photochem Photobiol ; 64(1): 205-10, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8787015

RESUMO

The results of this work show that the resistance of Escherichia coli cells to the photodynamic action of methylene blue is increased by the addition of glucose to the media in which they are grown. It is postulated that the increased resistance may be due to lowered retention of the dye by cells grown in the presence of glucose, leading to the diminution in DNA damage revealed in the alkaline sucrose gradients. The role of cyclic adenosine-monophosphate in the protective action of glucose is discussed.


Assuntos
Escherichia coli/efeitos dos fármacos , Glucose/farmacologia , Azul de Metileno/farmacologia , Fármacos Fotossensibilizantes/farmacologia , AMP Cíclico/metabolismo , Dano ao DNA , Escherichia coli/metabolismo , Escherichia coli/efeitos da radiação , Azul de Metileno/farmacocinética , Fotobiologia , Fármacos Fotossensibilizantes/farmacocinética
15.
J Chromatogr A ; 853(1-2): 151-8, 1999 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-10486721

RESUMO

The inner walls of 50 microns fused-silica capillaries are etched by ammonium hydrogendifluoride and then modified by the silanization/hydrosilation method with a chiral selector. Three different types of selectors were evaluated: lactone, beta-cyclodextrin and naphthylethylamine. Each of the bonded chiral stationary phases provided at least partial separation for one type of racemic solute. These results confirm that bonded organic moieties on the etched inner wall of a capillary can provided sufficient solute-bonded phase interactions to influence the retention of molecules driven through a capillary by electroosmosis or a combination of electroosmosis and electrophoretic mobility.


Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , beta-Ciclodextrinas , Ciclodextrinas/química , Estudos de Viabilidade , Lactonas/química , Peptídeos/análise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Estereoisomerismo
16.
Int J Radiat Biol ; 69(3): 345-50, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8613684

RESUMO

Methylene blue (MB) is shown to sensitize E. coli cells to the effects of X-rays. This sensitization is dependent on factors such as dye concentration, incubation temperature, membrane permeability, and repair capacities, suggesting that the binding and/or penetration of the dye into the cells determines the potentiation of the lethal effects of X-rays by MB. It is also demonstrated that the presence of the polymerase 1 enzyme is essential for this sensitization to take place. Since MB is known to penetrate, accumulate, and be retained preferentially in some malignant tissues, the possibility of using this dye as a specific sensitizer to X-rays in the radiotherapy of some cancers is discussed.


Assuntos
Corantes/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/efeitos da radiação , Azul de Metileno/farmacologia , Tolerância a Radiação/efeitos dos fármacos , Radiossensibilizantes/farmacologia , Terapia Combinada , DNA Polimerase I/metabolismo , Reparo do DNA , Relação Dose-Resposta à Radiação , Escherichia coli/enzimologia , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/radioterapia , Tolerância a Radiação/fisiologia
17.
Int J Radiat Biol ; 76(9): 1289-94, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10993640

RESUMO

PURPOSE: To investigate the mechanism of methylene blue-induced radiosensitization in Escherichia coli cells. MATERIALS AND METHODS: Bacteriophage lambda15 was irradiated with X-rays in the presence or absence of methylene blue (MB) and infected into bacteria with different repair capabilities preincubated with or without MB. The survival of the bacteriophage in each bacterial strain was used to quantify MB-induced radiosensitization. DNA repair in bacteria irradiated with X-rays and incubated with or without MB was examined by alkaline and neutral sucrose gradients. An in vitro repair system of pBR322 plasmid DNA irradiated with X-rays was designed to determine the repair enzyme targeted by MB. CONCLUSIONS: MB impairs the repair activity of the polymerase 1 enzyme in E. coli cells, sensitizing these bacteria to the lethal effects of ionizing radiation. Since MB accumulates preferentially in some malignant tumours, it will be of interest to investigate its effects on the repair of irradiated human cells.


Assuntos
DNA Polimerase I/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/efeitos da radiação , Azul de Metileno/farmacologia , Tolerância a Radiação , Centrifugação com Gradiente de Concentração , DNA/efeitos dos fármacos , DNA/efeitos da radiação , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/efeitos da radiação , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/efeitos da radiação , Relação Dose-Resposta à Radiação , Plasmídeos/efeitos dos fármacos , Plasmídeos/efeitos da radiação , Raios X
18.
Int J Radiat Biol ; 62(3): 321-6, 1992 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-1356134

RESUMO

There is interest in the use of photodynamic therapy for the treatment of certain diseases, including cancer. However, weak penetration of visible light in tissues has restricted its use. In this study the possibility of enhancing photodynamic effects by the use of energies that penetrate more deeply in tissues was investigated. Weak electric currents (1.0 mA) applied to Escherichia coli cells for short periods, producing little or no lethal damage, was found to act synergistically with the photodynamic action of methylene blue, significantly enhancing the effects of this treatment. This synergism exists also between electrolysis and X-rays but not between electrolysis and UV-254 nm. It is suggested that this synergism might eventually be used to improve the results obtained in therapeutic practice based on the utilization of photodynamic action.


Assuntos
Eletricidade , Azul de Metileno , Fotoquimioterapia/métodos , Escherichia coli
19.
Respir Physiol Neurobiol ; 139(3): 271-80, 2004 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-15122993

RESUMO

The aim of this study was to determine whether an intrapleural injection of barium sulphate would produce pleurodesis in rats. Additionally, respiratory mechanics and pleural remodelling were analysed. Single intrapleural injection of barium sulphate (100%) or saline was given to Wistar rats. Respiratory system, lung, and chest wall elastic, resistive and viscoelastic/inhomogeneous pressures were measured by the end-inflation occlusion method at 2 and 30 days after injection. The pleura were examined for gross and histopathological evidence of pleural inflammation and fibrosis, and the underlying lungs were also studied by morphometry. All pulmonary mechanical parameters increased at day 2, but were not different from control at 30 days after injection. Chest wall mechanical parameters did not change. Macroscopic evaluation demonstrated pleural adherence without haemothorax. Histopathologic analysis showed pleural inflammation and fibrosis. There was no alveolar inflammation or fibrosis in both groups. In conclusion, barium sulphate induced pleurodesis with either no changes in respiratory mechanics or lung lesion at day 30.


Assuntos
Sulfato de Bário/farmacologia , Pleura/efeitos dos fármacos , Pleurodese , Mecânica Respiratória/efeitos dos fármacos , Animais , Fibrose/etiologia , Capacidade Residual Funcional/efeitos dos fármacos , Histologia , Inflamação/etiologia , Complacência Pulmonar/efeitos dos fármacos , Masculino , Pleura/patologia , Pleura/fisiologia , Ratos , Ratos Wistar , Mecânica Respiratória/fisiologia , Sistema Respiratório/efeitos dos fármacos , Tórax/efeitos dos fármacos , Tórax/patologia , Fatores de Tempo
20.
J Photochem Photobiol B ; 22(2): 157-64, 1994 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8176549

RESUMO

Heat-shock-induced resistance to far-UV (FUV) radiation was studied in Escherichia coli. The induction of FUV resistance was shown to be dependent on the products of the genes uvrA and polA in bacteria irradiated at 254 nm. Heat shock increased the resistance to 280 nm radiation in a uvrA6 recA13 mutant. Heat shock lowered the mutation frequency (reversion to tryptophan proficiency) in wild-type or uvrA strains irradiated at 254 nm. When these strains were irradiated at 280 nm, heat shock did not interfere with the mutation frequency in the wild-type strain, but greatly enhanced mutations in the uvrA mutant. After heat-shock treatment, the wild-type strain irradiated at 254 nm showed increased DNA degradation, indicating enhanced repair activity. However, heat shock did not stimulate SOS repair triggered by FUV. An increased survival of bacteriophages irradiated with FUV and inoculated into heat-shock-treated bacteria was not detected. The possibility that heat shock enhances excision repair activity in a wavelength-dependent manner is discussed.


Assuntos
Bacteriófago lambda/efeitos da radiação , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/efeitos da radiação , Temperatura Alta , Raios Ultravioleta , Dano ao DNA , Reparo do DNA , DNA Bacteriano/efeitos da radiação , Relação Dose-Resposta à Radiação , Escherichia coli/genética , Marcadores Genéticos , Cinética , Especificidade da Espécie , Fatores de Tempo
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