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1.
Cancer Radiother ; 23(6-7): 658-661, 2019 Oct.
Artigo em Francês | MEDLINE | ID: mdl-31471252

RESUMO

Stereotactic radiotherapy represents a fundamental change in the practice of radiotherapy of lung cancers. Despite the great heterogeneity of sites, techniques, and doses, most studies found a high local control rate, around 70 to 90% at 2 years, and reduced toxicity, around 5% of grade 3 at 2 years. Stereotactic radiotherapy can be realized either by a dedicated accelerator (CyberKnife®) or by a conventional accelerator associated with specific systems. The two modalities deliver a very precise irradiation whose very good results published to date are similar. Some technical characteristics specific to each type of linear accelerator could guide the choice according to the target volume treated.


Assuntos
Neoplasias Pulmonares/radioterapia , Aceleradores de Partículas , Radiocirurgia/instrumentação , Humanos , Movimentos dos Órgãos , Órgãos em Risco/efeitos da radiação , Radiocirurgia/métodos , Respiração , Resultado do Tratamento
2.
Cancer Radiother ; 23(6-7): 496-499, 2019 Oct.
Artigo em Francês | MEDLINE | ID: mdl-31471251

RESUMO

Stereotactic radiotherapy of oligometastases, mono- or hypofractionated, represents a fundamental change in the practice of the specialty as it was developed for a century. Despite the great heterogeneity of sites, techniques, and doses, most studies found a high local control rate, around 70 to 90% at 2 years, and reduced toxicity, around 5% of grade 3 at 2 years. Four main phase II and III trials are underway in France. Future research concerns the association of stereotactic radiotherapy with immunotherapy or different conventional chemotherapy protocols, the identification of the best clinical presentations, and optimization of fractionation and biological dose for poor prognosis localizations.


Assuntos
Ensaios Clínicos Fase II como Assunto , Ensaios Clínicos Fase III como Assunto , Neoplasias/radioterapia , Radiocirurgia/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto , Anticorpos Monoclonais/uso terapêutico , Antineoplásicos Imunológicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Ósseas/radioterapia , Neoplasias Ósseas/secundário , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/radioterapia , Terapia Combinada/métodos , Previsões , França , Humanos , Imunoterapia , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/radioterapia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Masculino , Metástase Neoplásica , Neoplasias/patologia , Neoplasias/terapia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/radioterapia , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Carcinoma de Células Escamosas de Cabeça e Pescoço/radioterapia
3.
Cancer Radiother ; 23(5): 365-369, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31300329

RESUMO

PURPOSE: The main goal of palliative radiotherapy is to reduce patient's discomfort. But sometimes patients do not receive any benefits from this treatment because of rapid worsening of their general condition. This prospective monocentric study assessed the effective delivery of palliative radiotherapy. MATERIALS AND METHODS: From 1st December 2015 to 29th February 2016, all consecutive patients receiving palliative radiotherapy in our hospital were included. The primary endpoint was the effective delivery of palliative radiotherapy according to the initial prescription (total dose, overall treatment time and fractionation). The secondary endpoints were the number of treatment breaks, the clinical benefit, the number of deaths and the delays for admission in the palliative care unit. RESULTS: Fifty-nine patients were included and 64 treatments were analysed. The treatment sites were: bone (70.3%) and brain (21.9%). The treatment goals were: pain control only (43.8%), decompression only (21.9%), pain control and decompression (32.8%), haemostatic aim (1.6%). Palliative treatment was achieved in 57 cases (89%). Temporary interruption of the radiotherapy treatment was necessary in six cases (9.4%; three for medical reason, three for logistic reason). The main reason of permanent interruption was worsening of performance status (seven cases). Palliation of symptoms (complete or partial responses) was obtained in 44 cases (68.8%). Seven patients (11.9%) died during the month after the end of the treatment. No delay or cancellation for admission in the palliative care unit were observed. CONCLUSION: Palliative radiotherapy was completed as originally planned in 51 cases (79.9%) with a clinical benefit for 44 cases (68.8%). Radiation therapy must not be neglected as a palliative treatment at the end-of-life.


Assuntos
Neoplasias Ósseas/secundário , Neoplasias Encefálicas/secundário , Cuidados Paliativos , Radioterapia Conformacional , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Ósseas/radioterapia , Neoplasias Encefálicas/radioterapia , Fracionamento da Dose de Radiação , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Dosagem Radioterapêutica , Radioterapia Conformacional/métodos , Resultado do Tratamento
4.
Cancer Radiother ; 23(4): 316-321, 2019 Jul.
Artigo em Francês | MEDLINE | ID: mdl-31153770

RESUMO

PURPOSE: To evaluate prospectively asthenia and the quality of life in patients treated by stereotactic body irradiation and to determine their predictive factors. METHODS AND MATERIALS: Quality of life was assessed by the EORTC QLQ-C30 and asthenia was evaluated with the Brief Fatigue Inventory (BFI), on the first day (T1), last day (T2) and 1-3 weeks after the end of treatment (T3). RESULTS: Sixty-three patients were treated with stereotactic body irradiation from February 2017 to May 2017 and 41 were included in the analysis (22 patients excluded for lack of understanding, organization, psychologic disorders or refusal). The mean number of fractions was 5 (±2). The compliance to quality of life assessment was 98%, 95% was 81% at T1, T2 and T3, respectively. An increase of asthenia and a worsened quality of life were found in 12 (29%) and 14 (34%) patients between T1 and T2. Univariate analysis demonstrated a correlation between asthenia and quality of life were correlated with performans status (P=0.03 and 0.05 respectively), hemoglobin level (p=0.01 and 0.004), albumin level (P=0.01 and 0.06), distance between home and radiotherapy department (P=0.05 and 0.02). Multivariate analysis demonstrated a correlation between female gender (P=0.012), albumin level (P<0.001), distance over 25km (P<0.001) with asthenia, and albumin level (P=0.003), hemoglobin level (P=0.004) and previous chemotherapy (P=0.003) with quality of life. No influence of stereotactic body ratiotherapy parameters was seen. CONCLUSION: Despite hypofractionation, stereotactic body radiotherapy induced asthenia and deterioration of quality of life.


Assuntos
Astenia/etiologia , Qualidade de Vida , Radiocirurgia/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Hemoglobinas/análise , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estudos Prospectivos , Hipofracionamento da Dose de Radiação , Albumina Sérica/análise , Fatores Sexuais , Inquéritos e Questionários
5.
Cancer Radiother ; 22(8): 773-777, 2018 Dec.
Artigo em Francês | MEDLINE | ID: mdl-30360973

RESUMO

PURPOSE: In 2008, the French national society of radiation oncology (SFRO) and the association for radiation oncology continued education (AFCOR) created Siriade, an e-learning website dedicated to contouring. MATERIAL AND METHODS: Between 2015 and 2017, this platform was updated using the latest digital online tools available. Two main sections were needed: a theoretical part and another section of online workshops. RESULTS: Teaching courses are available as online commented videos, available on demand. The practical section of the website is an online contouring workshop that automatically generates a report quantifying the quality of the user's delineation compared with the experts'. CONCLUSION: Siriade 2.0 is an innovating digital tool for radiation oncology initial and continuous education.

6.
Eur Ann Otorhinolaryngol Head Neck Dis ; 133(4): 257-62, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27291482

RESUMO

GOALS: Prospective evaluation of salivary gland preservation, overall survival and local recurrence-free survival after head and neck cancer treated by helical tomotherapy (HT). MATERIAL AND METHODS: From March 2007 to February 2009, 30 patients with head and neck cancer were treated by HT. The salivary excretion fraction (SEF) was assessed by technetium salivary gland scintigraphy before, and 6, 12 and 18 months after HT to define salivary gland preservation rates. Patients were reviewed every 3 months to assess clinical toxicity. RESULTS: The median follow-up was 4.3 years. The mean dose to the ipsilateral parotid gland (IPG) was 25.4Gy. Good preservation of parotid gland function was observed in 84% of the 19 patients evaluated by scintigraphy at 18 months. The 5-year local recurrence-free survival (LRFS) was 100% among the 6 patients who received a dose of more than 26Gy to the parotid gland. The 28-month LRFS was 33% in the group that received a dose of less than 20Gy versus 91% in the group that received a dose of more than 20Gy to the IPG. CONCLUSIONS: Helical tomotherapy reduced the incidence and severity of xerostomia. A mean dose to the parotid between 20 and 26Gy allowed preservation of salivary function without compromising treatment efficacy. However, parotid-sparing HT requiring a mean dose less than 20Gy is associated with an increased risk of recurrence.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Tratamentos com Preservação do Órgão , Radioterapia de Intensidade Modulada , Glândulas Salivares/diagnóstico por imagem , Adulto , Idoso , Carcinoma/mortalidade , Carcinoma/radioterapia , Feminino , Seguimentos , Neoplasias de Cabeça e Pescoço/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Estudos Prospectivos , Dosagem Radioterapêutica , Xerostomia/prevenção & controle
7.
Cancer Radiother ; 20(3): 169-75, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27080576

RESUMO

PURPOSE: To retrospectively analyse female patients treated for urethral adenocarcinoma, modalities of treatment and long-term outcomes. PATIENTS: Four cases of primary female urethral adenocarcinoma were treated in the departments of urology and radiation-oncology at Georges-Pompidou and Necker hospitals (France) over a 7-year period. RESULTS: All of them underwent surgery, with three presenting stage pT3-pT4 and one a positive cytology on inguinal node. Three patients received adjuvant cisplatin-based chemoradiotherapy up to 60Gy, and one preoperative chemoradiotherapy at 45Gy. Two recurrences were observed: one local relapse occurred at 9months from the diagnosis and was treated by anterior pelvic exenteration followed by chemoradiotherapy, with no recurrence. One tumour relapsed both at the local level and on distant metastatic sites at 9months from the diagnosis, and died 21months after this progression. Median survival and progression-free survival are respectively 4.2years and 13months. Three patients are alive at 7, 4.5 and 3years from diagnosis. CONCLUSION: Female urethral adenocarcinoma is a very rare entity and often present in locally advanced stages. Initial extensive surgery with pelvic exenteration should be considered, followed by chemoradiotherapy according to the surgical margins and lymph nodes involvement.


Assuntos
Adenocarcinoma/terapia , Neoplasias Uretrais/terapia , Terapia Combinada , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento
8.
Bone Joint J ; 97-B(2): 177-84, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25628279

RESUMO

Conventional cemented acetabular components are reported to have a high rate of failure when implanted into previously irradiated bone. We recommend the use of a cemented reconstruction with the addition of an acetabular reinforcement cross to improve fixation. We reviewed a cohort of 45 patients (49 hips) who had undergone irradiation of the pelvis and a cemented total hip arthroplasty (THA) with an acetabular reinforcement cross. All hips had received a minimum dose of 30 Gray (Gy) to treat a primary nearby tumour or metastasis. The median dose of radiation was 50 Gy (Q1 to Q3: 45 to 60; mean: 49.57, 32 to 72). The mean follow-up after THA was 51 months (17 to 137). The cumulative probability of revision of the acetabular component for a mechanical reason was 0% (0 to 0%) at 24 months, 2.9% (0.2 to 13.3%) at 60 months and 2.9% (0.2% to 13.3%) at 120 months, respectively. One hip was revised for mechanical failure and three for infection. Cemented acetabular components with a reinforcement cross provide good medium-term fixation after pelvic irradiation. These patients are at a higher risk of developing infection of their THA.


Assuntos
Artroplastia de Quadril , Prótese de Quadril , Ossos Pélvicos/efeitos da radiação , Desenho de Prótese , Neoplasias Urogenitais/cirurgia , Idoso , Idoso de 80 Anos ou mais , Artroplastia de Quadril/métodos , Neoplasias Ósseas/radioterapia , Cimentação , Feminino , Neoplasias Femorais/cirurgia , Necrose da Cabeça do Fêmur/cirurgia , Fraturas Espontâneas/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Osteíte/cirurgia , Estudos Retrospectivos , Neoplasias Ureterais/radioterapia , Neoplasias da Bexiga Urinária/cirurgia
9.
Cancer Radiother ; 15(3): 238-49; quiz 257, 2011 Jun.
Artigo em Francês | MEDLINE | ID: mdl-21435931

RESUMO

Ionizing radiation may interfere with electric components of pacemakers or implantable cardioverter-defibrillators. The type, severity and extent of radiation damage to pacemakers, have previously been shown to depend on the total dose and dose rate. Over 300,000 new cancer cases are treated yearly in France, among which 60% are irradiated in the course of their disease. One among 400 of these patients has an implanted pacemaker or defibrillator. The incidence of pacemaker and implanted cardioverter defribillator increases in an ageing population. The oncologic prognosis must be weighted against the cardiologic prognosis in a multidisciplinary and transversal setting. Innovative irradiation techniques and technological sophistications of pacemakers and implantable cardioverter-defibrillators (with the introduction of more radiosensitive complementary metal-oxide-semiconductors since 1970) have potentially changed the tolerance profiles. This review of the literature studied the geometric, dosimetric and radiobiological characteristics of the radiation beams for high energy photons, stereotactic irradiation, protontherapy. Standardized protocols and radiotherapy optimization (particle, treatment fields, energy) are advisable in order to improve patient management during radiotherapy and prolonged monitoring is necessary following radiation therapy. The dose received at the pacemaker/heart should be calculated. The threshold for the cumulated dose to the pacemaker/implantable cardioverter-defibrillator (2 to 5 Gy depending on the brand), the necessity to remove/displace the device based on the dose-volume histogram on dosimetry, as well as the use of lead shielding and magnet are discussed.


Assuntos
Desfibriladores Implantáveis , Neoplasias/radioterapia , Marca-Passo Artificial , Idoso , Idoso de 80 Anos ou mais , Arritmias Cardíacas/prevenção & controle , Arritmias Cardíacas/terapia , Remoção de Dispositivo , Relação Dose-Resposta à Radiação , Eletrodos Implantados , Desenho de Equipamento , Falha de Equipamento , Feminino , Humanos , Pessoa de Meia-Idade , Monitorização Fisiológica , Proteção Radiológica , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Semicondutores
10.
Cancer Radiother ; 14(4-5): 246-9, 2010 Jul.
Artigo em Francês | MEDLINE | ID: mdl-20615744

RESUMO

Ionizing radiation is frequently used for cancers with a curative intent for many patients. The total dose delivered on the tumour plays a major factor for locoregional control. Increasing the dose to the tumour volume is generally correlated with an increased dose to normal tissue. Dose constraints to organs at risk must be taken into account for the planning of external beam radiation. A high dose will generate more acute and late side effects. Medical doctors should record these toxicities prospectively. Registration and grading should be simple, reproducible and sensitive in order to obtain an accurate and appropriate evaluation for each organ. Several scales have been published in the literature (WHO, EORTC/RTOG, LENT-SOMA, NCI CTCAE) but none have a satisfactory level. The National Cancer Institute has proposed several version of the CTCAE and its latest version 4.0, currently appears to be the most adapted. The advantage of using only this common and universal classification will be to harmonize practices and have a common language.


Assuntos
Neoplasias/radioterapia , Lesões por Radiação/etiologia , Radiação Ionizante , Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Humanos , Neoplasias/tratamento farmacológico , Especificidade de Órgãos , Lesões por Radiação/classificação , Radioterapia/efeitos adversos , Radioterapia/classificação , Dosagem Radioterapêutica
12.
Ophthalmology ; 107(10): 1803, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11013174
13.
Ophthalmology ; 106(9): 1841-6, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10485560

RESUMO

OBJECTIVE: Quantitative computerized tomography (QCT), a scanning method routinely used to classify tissues based on their radio density, was used to detect choroidal calcification. DESIGN: Case reports. PARTICIPANTS: Two patients with known or suspected choroidal calcium-choroidal osteoma (CO) and pseudoxanthoma elasticum (PXE) and five normal control subjects were assessed. INTERVENTION: The CT scan of choroid, B-scan ultrasound, fluorescein angiography. MAIN OUTCOME MEASURES: The QCT scan used to detect the presence of calcium based on a readout greater than 90. RESULTS: Calcium was detected bilaterally, as predicted, in PXE, and in both eyes of CO, although only one eye had a clinically noted lesion. No control eye gave a scale readout consistent with calcium. No findings suggestive of calcium were noted with B-scan ultrasound or fluorescein angiography in PXE or CO. CONCLUSION: The QCT can detect calcium in the choroid when B-scan ultrasonography and CT scan fine sectioning fail to identify calcium despite high clinical suspicion.


Assuntos
Estrias Angioides/diagnóstico por imagem , Calcinose/diagnóstico por imagem , Cálcio/análise , Neoplasias da Coroide/diagnóstico por imagem , Osteoma/diagnóstico por imagem , Pseudoxantoma Elástico/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Estrias Angioides/patologia , Calcinose/patologia , Neoplasias da Coroide/patologia , Técnicas de Diagnóstico Oftalmológico , Angiofluoresceinografia , Fundo de Olho , Humanos , Masculino , Osteoma/patologia , Pseudoxantoma Elástico/patologia
16.
Genetics ; 137(2): 353-9, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8070649

RESUMO

Leu+ mutants from Salmonella typhimurium leu-500 strain MA412 arise at high frequencies and mutant colonies appear over a broad range of time on selective plates. This observation suggested that these Leu+ mutants might be induced or "directed."= If such a mechanism was responsible, mutants should originate on selective plates rather than in the preceding culture in nonselective conditions and should give rise to Poisson-like fluctuation curves upon plating of sister cultures on selective medium. Poisson-like distribution profiles were indeed observed for Leu+ mutants of S. typhimurium MA412. However, an explanation for the observed Poisson-like fluctuation patterns without a need for selection-induced mutations was found. Microscopical analysis and cell mass/viable count measurements showed that the size of Leu+ mutant cells was often much larger than those of nonmutants. This size difference was a stable characteristic of a large proportion of Leu+ mutants, was observed both in stationary and growing culture and did not measurably affect the division rates of the cells in nutrient broth. As the transition from normal-sized nonmutant to oversized mutant cells during the nonselective culture phase of the fluctuation experiment may have been accompanied by a period with no or few completed cell division cycles, the number of mutant offspring may have been smaller than that of sibling nonmutants. Such underrepresentation of mutants in the final culture is expected to give rise to Poisson-like fluctuation patterns without invoking "directed" mutations.


Assuntos
Leucina/metabolismo , Mutação , Salmonella typhimurium/genética , Divisão Celular , Cinética , Distribuição de Poisson , Salmonella typhimurium/citologia , Salmonella typhimurium/crescimento & desenvolvimento , Especificidade da Espécie , Fatores de Tempo
17.
Microb Releases ; 2(1): 23-8, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8261166

RESUMO

Genetically modified microorganisms (GMMs) are frequently used as producers of mammalian immunomodulatory proteins, e.g. interferons and interleukins. Here we have examined the question of whether such GMMs interact in a way different from that of their non-modified parent micro-organisms with mammalian antimicrobial defence systems. As a typical GMM host micro-organism we used Escherichia coli K12, and as a typical immunomodulatory protein produced by a GMM we used mouse interferon-gamma (MuIFN-gamma). Two experimental systems are described in which synergistic "toxic" biological effects are induced by a combined treatment with E. coli and MuIFN-gamma but not, or less so, by the parental strain and the recombinant protein separately. First, it is shown that the IFN-gamma-producing GMM, or mixtures of E. coli cells and IFN-gamma, are cytolytic for mouse embryo fibroblastoid cells (MEF), whereas no cell killing occurs in MEF cultures treated with control E. coli cells or in those treated with bacteria-free recombinant IFN-gamma. Second, it is demonstrated that intraperitoneal injection in mice of high but not low numbers of control E. coli K12 cells induces a shock-like mortality, whereas co-injection with IFN-gamma induces killing at low numbers. IFN-gamma-producing E. coli cells cause a mortality rate that does not differ from that of control E. coli cells, probably because in these experimental conditions the level of recombinant MuIFN-gamma per cell is insufficiently high. Taken together, these data indicate that synergistic toxic effects induced by bacteria and their recombinant products can occur and may in certain situations enhance the intrinsic toxic capacity of the GMM. Synergistic toxic effects may thus be of relevance for identifying the safety level that should be employed when working with GMMs.


Assuntos
Toxinas Bacterianas/toxicidade , Escherichia coli/patogenicidade , Interferon gama/toxicidade , Choque Séptico , Animais , Sinergismo Farmacológico , Escherichia coli/genética , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes , Fatores de Risco , Choque Séptico/mortalidade
18.
Microb Releases ; 2(1): 29-34, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8261167

RESUMO

Monitoring of microbial DNA in soils by dot blot hybridization and PCR analysis is a useful technique for gaining insight into the survival and impact of genetically modified micro-organisms released in the environment. Most methods of DNA isolation from soils require a large number of purification steps rendering them unsuitable for quantitative analysis of multiple samples. Here we describe a very rapid method for the isolation and purification of multiple samples of soil DNA that can be used directly for dot blot hybridization and PCR analysis. Soil DNA extracts are prepared by lysozyme/SDS treatment at pH 9.0 and purified by ammonium acetate precipitation and Sephadex G50 gel filtration. In a practical application of this method, sandy soil samples were seeded with Alcaligenes eutrophus cells and exposed to high temperature (42 degrees C) or desiccation. As a result, the number of culturable A. eutrophus cells which could be recovered from the soil samples quickly declined. However, the concentration of a marker gene encoding resistance to cadmium, cobalt and zinc (czc) remained unaltered.


Assuntos
Alcaligenes/genética , DNA Bacteriano/isolamento & purificação , Monitoramento Ambiental/métodos , Microbiologia do Solo , Sequência de Bases , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Reação em Cadeia da Polimerase
19.
J Bacteriol ; 175(6): 1674-81, 1993 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8383664

RESUMO

Alcaligenes eutrophus A5 catabolizes biphenyl to CO2 via benzoate and 4-chlorobiphenyl to 4-chlorobenzoate. In curing and conjugation experiments, the A5 endogenous 51-kb IncP1 plasmid pSS50 was found to be dispensable for biphenyl and 4-chlorobiphenyl catabolism. Transfer of the biphenyl- and 4-chlorobiphenyl-degrading phenotype by means of pSS50 was observed at a frequency of 10(-5) per transferred plasmid in matings of A5 with other A. eutrophus strains. Transconjugants harbor enlarged pSS50 derivatives which contain additional genetic information governing the oxidation of biphenyl and 4-chlorobiphenyl to benzoate and 4-chlorobenzoate and originating from the chromosome of strain A5. The following observations indicate that the catabolic genes reside on a 59-kb large transposon (Tn4371) for which a restriction map is presented. (i) Tn4371 transposes between different replicons and at different locations of the same replicon. (ii) Transposition was observed in a Rec- strain of A. eutrophus. (iii) Tn4371 transposes as a single, contiguous piece of DNA. Although an RP4::Tn4371 plasmid was stably maintained in different hosts, the plasmid conferred growth on biphenyl only when present in strains of A. eutrophus and in an Acinetobacter sp. strain.


Assuntos
Alcaligenes/genética , Compostos de Bifenilo/metabolismo , Elementos de DNA Transponíveis , Genes Bacterianos , Alcaligenes/metabolismo , Southern Blotting , Clonagem Molecular , Conjugação Genética , Estrutura Molecular
20.
Appl Environ Microbiol ; 59(1): 334-9, 1993 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8439161

RESUMO

Alcaligenes eutrophus strains exhibiting both plasmid-borne heavy metal resistance and haloaromatic-degrading functions were obtained by intraspecific conjugation. The strains which we constructed expressed catabolic and resistance markers together. Degradation of various polychlorinated biphenyl isomers and 2,4-D (2,4-dichlorophenoxyacetic acid) was observed in the presence of 1 mM nickel or 2 mM zinc, provided that the metal resistance determinant was present in the catabolizing strain. Such strains may be useful for decontamination of sites that are polluted with both organic compounds and heavy metals.


Assuntos
Alcaligenes/efeitos dos fármacos , Alcaligenes/metabolismo , Hidrocarbonetos Halogenados/metabolismo , Metais/farmacologia , Alcaligenes/genética , Biodegradação Ambiental , Conjugação Genética , Poluentes Ambientais/metabolismo , Níquel/farmacologia , Plasmídeos , Especificidade da Espécie , Zinco/farmacologia
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