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1.
N Engl J Med ; 369(3): 213-23, 2013 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-23863050

RESUMO

BACKGROUND: Radium-223 dichloride (radium-223), an alpha emitter, selectively targets bone metastases with alpha particles. We assessed the efficacy and safety of radium-223 as compared with placebo, in addition to the best standard of care, in men with castration-resistant prostate cancer and bone metastases. METHODS: In our phase 3, randomized, double-blind, placebo-controlled study, we randomly assigned 921 patients who had received, were not eligible to receive, or declined docetaxel, in a 2:1 ratio, to receive six injections of radium-223 (at a dose of 50 kBq per kilogram of body weight intravenously) or matching placebo; one injection was administered every 4 weeks. In addition, all patients received the best standard of care. The primary end point was overall survival. The main secondary efficacy end points included time to the first symptomatic skeletal event and various biochemical end points. A prespecified interim analysis, conducted when 314 deaths had occurred, assessed the effect of radium-223 versus placebo on survival. An updated analysis, when 528 deaths had occurred, was performed before crossover from placebo to radium-223. RESULTS: At the interim analysis, which involved 809 patients, radium-223, as compared with placebo, significantly improved overall survival (median, 14.0 months vs. 11.2 months; hazard ratio, 0.70; 95% confidence interval [CI], 0.55 to 0.88; two-sided P=0.002). The updated analysis involving 921 patients confirmed the radium-223 survival benefit (median, 14.9 months vs. 11.3 months; hazard ratio, 0.70; 95% CI, 0.58 to 0.83; P<0.001). Assessments of all main secondary efficacy end points also showed a benefit of radium-233 as compared with placebo. Radium-223 was associated with low myelosuppression rates and fewer adverse events. CONCLUSIONS: In this study, which was terminated for efficacy at the prespecified interim analysis, radium-223 improved overall survival. (Funded by Algeta and Bayer HealthCare Pharmaceuticals; ALSYMPCA ClinicalTrials.gov number, NCT00699751.).


Assuntos
Neoplasias Ósseas/secundário , Neoplasias da Próstata/radioterapia , Rádio (Elemento)/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Neoplasias Ósseas/mortalidade , Neoplasias Ósseas/radioterapia , Método Duplo-Cego , Humanos , Isótopos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/mortalidade , Neoplasias da Próstata/patologia , Rádio (Elemento)/efeitos adversos
2.
Chemosphere ; 90(11): 2714-21, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23290947

RESUMO

Glycol ethers are a class of semi-volatile substances used as solvents in a variety of consumer products like cleaning agents, paints, cosmetics as well as chemical intermediates. We determined 11 metabolites of ethylene and propylene glycol ethers in 44 urine samples of German residents (background level study) and in urine samples of individuals after exposure to glycol ethers during cleaning activities (exposure study). In the study on the background exposure, methoxyacetic acid and phenoxyacetic acid (PhAA) could be detected in each urine sample with median (95th percentile) values of 0.11 mgL(-1) (0.30 mgL(-1)) and 0.80 mgL(-1) (23.6 mgL(-1)), respectively. The other metabolites were found in a limited number of samples or in none. In the exposure study, 5-8 rooms were cleaned with a cleaner containing ethylene glycol monobutyl ether (EGBE), propylene glycol monobutyl ether (PGBE), or ethylene glycol monopropyl ether (EGPE). During cleaning the mean levels in the indoor air were 7.5 mgm(-3) (EGBE), 3.0 mgm(-3) (PGBE), and 3.3 mgm(-3) (EGPE), respectively. The related metabolite levels analysed in the urine of the residents of the rooms at the day of cleaning were 2.4 mgL(-1) for butoxyacetic acid, 0.06 mgL(-1) for 2-butoxypropionic acid, and 2.3 mgL(-1) for n-propoxyacetic acid. Overall, our study indicates that the exposure of the population to glycol ethers is generally low, with the exception of PhAA. Moreover, the results of the cleaning scenarios demonstrate that the use of indoor cleaning agents containing glycol ethers can lead to a detectable internal exposure of residents.


Assuntos
Exposição Ambiental/estatística & dados numéricos , Poluentes Ambientais/urina , Etilenoglicóis/urina , Propilenoglicol/urina , Adulto , Feminino , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
3.
Gesundheitswesen ; 71(5): 275-80, 2009 May.
Artigo em Alemão | MEDLINE | ID: mdl-19294617

RESUMO

Polychlorinated biphenyls (PCB) were widely used in numerous industrial and commercial applications in high quantities in the past. Based on their persistence in the environment, their tendency to accumulate in the organism and their specific health effects, PCBs have to be assessed as critical substances. Because the dietary intake was assumed to be the main intake route, the Integrated Exposure Assessment Survey (INES) aimed to measure the recent exposure to PCBs in Germany. The study consisted of 10 female and 10 male participants living in Munich and surroundings. The participants collected dietary duplicates of all food consumed and prepared as for consumption over 7 consecutive days. Altogether the 6 non-dioxin-like PCB congeners 28, 52, 101, 138, 153 and 180 ndl-PCB or, respectively, indicator PCB and furthermore the congener 118 were detected using a gas chromatographic method. Dietary intake was calculated using the amount of food eaten daily and the results from the duplicates. Using the sum of PCB 138, 153 and 180 multiplied by 4, the daily intake ranged from 4.0 to 24.1 ng/kg b.w. (median: 9.5 ng/kg b.w.). On the contrary, the daily intake was 2.9 to 20.6 ng/kg b.w. (median: 11.2 ng/kg b.w.) if the sum of the 6 indicator PCBs multiplied by factor 2 was used for quantification. No sex-related difference of the dietary intake was observable. Overall, it can be concluded that the dietary PCB intake has further decreased in the last years in Germany. At present, the toxicological database is not suitable to assess the risks coming solely from the non-dioxin-like PCBs because it is not possible to differentiate between non dioxin-like and dioxin-like effects in toxicological studies. Nevertheless, a further reduction of PCB exposure via food by searching for possible sources is needed.


Assuntos
Dieta , Ingestão de Alimentos , Exposição Ambiental/análise , Poluentes Ambientais/análise , Análise de Alimentos , Contaminação de Alimentos/análise , Bifenilos Policlorados/análise , Adulto , Coleta de Dados , Dioxinas/análise , Feminino , Alemanha , Humanos , Pessoa de Meia-Idade
4.
Int Arch Occup Environ Health ; 80(4): 313-9, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16915390

RESUMO

OBJECTIVES: Perfluorinated compounds (PFCs) are a large group of chemicals produced for several decades and widely used for many industrial and consumer applications. Because of their global occurrence in different environmental media, their persistence, and their potential to bioaccumulate in organisms they are of toxicological and public concern. METHODS: In the present study, the internal exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in 356 human plasma samples collected from an adult population in Germany in 2005 is quantified. RESULTS: We were able to detect the target analytes in all plasma samples and observed a significant correlation between the PFOS and PFOA concentrations. In female participants, the levels of PFOS and PFOA ranged between 2.5-30.7 (median: 10.9 microg/l) and 1.5-16.2 microg/l (median: 4.8 microg/l), respectively. In males we observed concentrations from 2.1 to 55.0 microg/l (median: 13.7 microg/l) for PFOS and from 0.5 to 19.1 microg/l (median: 5.7 microg/l) for PFOA. A significant correlation between both PFOS and PFOA concentrations and gender was observed. We also found increased levels of the PFCs with increasing age of the participants, but this association reached statistical significance among females only. CONCLUSIONS: Our data agree well with results of other recent studies in Europe and suggest that the current exposure of the adult German population is lower than the exposure of the US and Canadian population. The sources of human exposure are currently not well understood. Toxicological implications are restricted to animal studies and occupational investigations not adequate for quantitative risk assessment in humans. Overall, more scientific research is necessary to characterize the body burden of PFCs (especially for relevant subsets of the population) and the main sources and routes, which are responsible for human exposure and possible health implications of these compounds.


Assuntos
Ácidos Alcanossulfônicos/sangue , Caprilatos/sangue , Exposição Ambiental/análise , Poluentes Ambientais/análise , Fluorocarbonos/sangue , Adolescente , Adulto , Idoso , Feminino , Alemanha/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Vigilância de Evento Sentinela
5.
Control Clin Trials ; 22(6 Suppl): 168S-80S, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11728622

RESUMO

Well-designed data management processes are essential in ensuring the quality of data collected in multicenter clinical trials. This paper describes the data management processes and systems that were developed by the data coordinating center of the Asthma Clinical Research Network. A combination of manual and electronic processes has been designed to process clinical trial data from the point of collection to statistical analysis. A distributed database management system consisting of modular applications for separate data processing activities was developed to enter, track, verify, validate, and edit collected data. In addition, processes for monitoring and reporting data quality are discussed.


Assuntos
Asma , Ensaios Clínicos como Assunto/métodos , Bases de Dados Factuais , Coleta de Dados , Feminino , Humanos , Pesquisa
6.
Am J Epidemiol ; 148(6): 528-38, 1998 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-9753007

RESUMO

Recent blood pressure trends reflect progress in hypertension control, but prevalent drug therapy precludes direct estimation of the component due to primary prevention. In data gathered on persons aged 35-74 years in three successive US health examination surveys (1960-1980), systolic blood pressure levels assuming no drug therapy were imputed by reassigning blood pressure to the upper end of the distribution for respondents reporting use of antihypertensive medication. Blood pressure was partitioned into four ordinal categories based on weighted percentiles of the 1960-1962 distributions for 35- to 44-year-old males and females who reported no use of antihypertensive medication. Cumulative logit models (alpha = 0.01) were used to estimate age- and sex-specific trends for blacks and whites within two strata (<25 or > or =25) of body mass index (BMI) (weight (kg)/height (m)2). Before imputation, systolic blood pressure decreased between 1960 and 1980; after imputation, significant decreases remained only in 35- to 44-year-olds. Strong associations of black race and BMI > or =25 with higher blood pressures were present in models with and without drug therapy. Thus, according to the models, there has been little progress in decreasing racial or BMI-related blood pressure differentials. Above the age of 44 years, blood pressure trends were largely attributable to medication use. In contrast, data for 35- to 44-year-olds suggest progress in primary prevention.


Assuntos
Pressão Sanguínea , Hipertensão/epidemiologia , Adulto , Negro ou Afro-Americano/estatística & dados numéricos , Distribuição por Idade , Idoso , População Negra , Índice de Massa Corporal , Feminino , Indicadores Básicos de Saúde , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/etnologia , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Razão de Chances , Distribuição por Sexo , Sístole , Estados Unidos/epidemiologia , População Branca/estatística & dados numéricos
7.
Prenat Diagn ; 17(11): 1081-4, 1997 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9399359

RESUMO

Apert syndrome is a rare craniosynostosis syndrome with significant bilateral syndactyly of the hands and feet. Usually it is detected by ultrasonography during the third trimester unless there is a family history. We present an interesting sporadic case with features consistent with Apert syndrome detected as early as the first trimester. A first-trimester ultrasound evaluation prior to chorionic villus sampling (CVS) for maternal age 41 was within normal limits except for the suggestion of a 'mitten-like' hand and proximally placed thumb. Mid-trimester ultrasound was not diagnostic; however, following the development of polyhydramnios in the third trimester, the evaluation of the digits and facial features were strongly suggestive of Apert syndrome. Amniocentesis was performed and a molecular diagnosis of Apert syndrome was made and confirmed on cord blood.


Assuntos
Acrocefalossindactilia/diagnóstico , Ultrassonografia Pré-Natal , Acrocefalossindactilia/diagnóstico por imagem , Acrocefalossindactilia/genética , Adulto , Feminino , Humanos , Reação em Cadeia da Polimerase , Gravidez , Primeiro Trimestre da Gravidez , Fatores de Risco
8.
Anticancer Res ; 17(6D): 4623-32, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9494580

RESUMO

Two human herpesviruses, HHV-6 and HHV-7, recently identified and closely related, were studied for their influence on cellular apoptosis and proliferation. Infection was monitored by viral DNA--and antigen expression. Apoptosis and cell proliferation were determined by immunocytological techniques and the markers p53, p21WAF/Cip, Bax, Bak, Bcl-2, cyclin D1 and PCNA, and also screened for signal transduction indicators such as c-H-ras, c-fos and raf-1. Cell differentiation and function was monitored by determining cell membrane receptors including Fas and CD specificities, and by ELISA tests for interleukin production. Both HHV-6 and HHV-7 readily infected their target cells, yet virus antigen expression and virus replication were less active in HHV-7 infection. Both viruses also induced GM-CFS production. Cell differentiation in terms of CD receptor expression was more pronounced in HHV-6 than in HHV-7 infection. No differences were found in the activity of signal transduction factors. There were quantitative differences in the activation of p53, Bax, p21WAF and Bcl-2 in HHV 6-infected CBC as compared to HHV-7 infection supporting the apoptosis cycle. CyclinD1 activity remained at lower levels in HHV-7 infected CBC, yet was high in similarly infected transformed SupT1 cells. In contrast, HHV-6 supported rather the p53/p21WAF apoptosis pathway in both untransformed CBC and transformed HSB1 cells. Both herpesviruses, HHV-6 and HHV-7, thus possessed similar biological activities in cultures of non-transformed susceptible cells, although with certain quantitative differences. The data reported here may further support the notion that HHV-7 is less active in inducing apoptosis thus favoring continued cell proliferation. The mechanism by which these viruses interfere with the network control of cell proliferation, differentiation and apoptosis appear more complicated than shown here and therefore afford a more detailed study, including a more sensitive technology than immunohistology.


Assuntos
Transformação Celular Viral , Herpesvirus Humano 6/fisiologia , Herpesvirus Humano 7/fisiologia , Antígenos Virais/biossíntese , Apoptose , Biomarcadores , Diferenciação Celular , Divisão Celular , Linhagem Celular , Ciclina D1/biossíntese , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/biossíntese , DNA Viral/biossíntese , Humanos , Imuno-Histoquímica , Proteínas de Membrana/biossíntese , Antígeno Nuclear de Célula em Proliferação/biossíntese , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Proteínas Proto-Oncogênicas c-fos/biossíntese , Proteínas Proto-Oncogênicas c-raf/biossíntese , Transdução de Sinais , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/biossíntese , Replicação Viral , Proteína Killer-Antagonista Homóloga a bcl-2 , Proteína X Associada a bcl-2
9.
Nephrol Dial Transplant ; 3(4): 435-9, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-2459635

RESUMO

In a randomised cross-over study we assessed total blood loss in 14 dialysis patients using 59Fe as a marker for measurement in a whole-body counting system. In one period the patients received standard heparin, in the other ORG 10172, a new low-molecular-weight-heparinoid. Our results show no significant difference between the two study periods with regard to blood loss and dialyser blood retention. In some patients a delayed bleeding ('oozing') from the puncture site was noticed as a side-effect of treatment with the low-molecular-weight-heparinoid. We conclude that this heparinoid is effective as an anticoagulant in regular dialysis treatment, but it seems to have no advantage over standard heparinisation with regard to occult bleeding. This may be related to the prolonged plasma anti-Xa activity (30.8 h) of this compound compared to standard heparin in dialysis patients.


Assuntos
Sulfatos de Condroitina , Dermatan Sulfato , Hemorragia Gastrointestinal/induzido quimicamente , Glicosaminoglicanos/efeitos adversos , Heparinoides/efeitos adversos , Heparitina Sulfato , Diálise Renal , Adulto , Feminino , Hemorragia Gastrointestinal/prevenção & controle , Heparina/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade
10.
J Immunopharmacol ; 6(4): 339-58, 1984.
Artigo em Inglês | MEDLINE | ID: mdl-6441823

RESUMO

The antimicrobial and antitumor effects of CP-20,961, a synthetic lipoid amine with immunomodulating properties, were investigated. Mice given CP-20,961 ip seven or three days before challenge with ip Listeria monocytogenes had a lower mortality than control mice. By contrast, CP-20,961 did not protect against lethal challenges of either Salmonella typhimurium or Toxoplasma gondii. In parallel with the in vivo studies, peritoneal macrophages from CP-20,961-injected mice inhibited multiplication of L. monocytogenes but not T. gondii. Further studies demonstrated that CP-20,961 protected mice against an ip challenge of P815 tumor cells as measured by survival time. This correlated with the ability of stimulated peritoneal macrophages to inhibit (3H-TdR uptake inhibition) and kill (Cr51 release) P815 cells in vitro. These data indicate that CP-20,961 affords protection against an ascitic mastocytoma tumor line and at least one, but not all, intracellular pathogens. The dissociation of the immunomodulating effect, which was reflected in peritoneal macrophage function, may be characteristic of this new class of immunomodulators.


Assuntos
Adjuvantes Imunológicos/farmacologia , Diaminas/farmacologia , Animais , Citotoxicidade Imunológica/efeitos dos fármacos , Feminino , Imunidade Inata/efeitos dos fármacos , Células Matadoras Naturais/imunologia , Listeriose/imunologia , Listeriose/mortalidade , Macrófagos/imunologia , Sarcoma de Mastócitos/imunologia , Camundongos , Camundongos Endogâmicos DBA , Neoplasias Experimentais/imunologia , Salmonelose Animal/imunologia , Salmonelose Animal/mortalidade , Salmonella typhimurium , Toxoplasmose/imunologia , Toxoplasmose/mortalidade
11.
Exp Parasitol ; 56(1): 1-8, 1983 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-6409658

RESUMO

The effect of sublethal inocula of Toxoplasma gondii on the course of listeriosis and salmonellosis in mice was investigated. Intravenous injection of T. gondii 24 hr after inoculation of Listeria monocytogenes increased mortality from 16% (L. monocytogenes alone) to 68% (L. monocytogenes + T. gondii) (P less than 0.001). Multiplication of L. monocytogenes in spleens also was increased significantly in mice given T. gondii. By 3 days after infection, mice that had received T. gondii and L. monocytogenes had approximately 10 times the number of L. monocytogenes per spleen compared to mice receiving L. monocytogenes alone. Similarly, mortality and the number of bacteria in spleens were increased in mice injected with Salmonella typhimurium and then inoculated with T. gondii. An in vitro assay of macrophage listeriacidal activity was used to investigate the mechanism of this decreased resistance. Peritoneal macrophages from mice injected with T. gondii were less bactericidal than macrophages from uninfected mice. Delayed hypersensitivity responses to L. monocytogenes antigen were markedly suppressed in mice injected with T. gondii. T. gondii infection appears to suppress both macrophage and T-lymphocyte function and may result in decreased resistance to infections caused by intracellular bacteria.


Assuntos
Listeriose/imunologia , Salmonelose Animal/imunologia , Toxoplasmose Animal/imunologia , Animais , Feminino , Hipersensibilidade Tardia , Imunidade Inata , Listeria monocytogenes/crescimento & desenvolvimento , Listeriose/complicações , Macrófagos/imunologia , Camundongos , Salmonelose Animal/complicações , Baço/microbiologia , Linfócitos T/imunologia , Toxoplasmose Animal/complicações
12.
Immunology ; 48(3): 543-50, 1983 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-6402445

RESUMO

This study was designed to explore the effects of acute nutritional deprivation (starvation) on macrophage function in mice. In vivo macrophage activity was increased by starvation, as determined by multiplication of Listeria monocytogenes in both spleens and livers after intravenous injection. Similarly, in vitro studies revealed that the capacity of peritoneal macrophages to kill listeria was enhanced by starvation. This function was increased further by the addition of small concentrations of lipopolysaccharide (LPS; 10-100 ng/ml). The bactericidal activity of macrophages from starved mice, however, did not reach the levels observed with macrophages from BCG-infected mice. Furthermore, LPS did not appear to be an important second signal for macrophage activation in vivo, as LPS-unresponsive mice (C3H/HeJ and A/J) were protected by starvation. In contrast to these results we found that starved mice were not protected against Toxoplasma gondii infection and that macrophages from starved mice were unable to prevent multiplication of toxoplasma trophozoites in vitro. In toto, these experiments suggest that macrophage function is enhanced by starvation, but that this enhancement is not sufficient to fulfill all criteria for macrophage activation.


Assuntos
Macrófagos/imunologia , Inanição/imunologia , Animais , Líquido Ascítico/citologia , Feminino , Imunidade Inata , Lipopolissacarídeos/farmacologia , Listeria monocytogenes/crescimento & desenvolvimento , Listeriose/complicações , Listeriose/imunologia , Fígado/microbiologia , Ativação de Macrófagos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos , Baço/microbiologia , Inanição/complicações , Toxoplasmose Animal/complicações , Toxoplasmose Animal/imunologia
13.
Nucleic Acids Res ; 9(17): 4403-12, 1981 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-6272206

RESUMO

The relationship between sedimentation coefficient and molecular weight for DNA sedimenting in preformed alkaline and neutral sucrose gradients was determined using absolute molecular weight standards (restriction fragments of plasmid pBR322 and phage lambda DNA). The range of calibration for alkaline gradients was extended to small DNA fragments (652 base-pairs) for the first time. The exponent b in the equation S20 degrees, w = aMb was found to be 0.380 in neutral gradients and 0.410 in alkali. The latter value differs significantly from previous estimates. The gradients were isokinetic, and the distance sedimented was shown to be directly proportional to the sedimentation coefficient at all times.


Assuntos
Bacteriófago lambda , DNA Viral , Desoxirribonucleases de Sítio Específico do Tipo II , Plasmídeos , Centrifugação com Gradiente de Concentração , Enzimas de Restrição do DNA/metabolismo , Desoxirribonuclease EcoRI , Peso Molecular
14.
J Bacteriol ; 145(1): 306-20, 1981 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-6450747

RESUMO

Controlled incorporation of uracil into the deoxyribonucleic acid (DNA) of lambda bacteriophages was achieved by growth on dut ung thy mutants of Escherichia coli. The frequency of substitution of uracil for thymine, estimated by alkaline sucrose sedimentation of phage DNA treated in vitro with uracil DNA glycosylase, ranged from 0.17 to 1.9%. The corresponding ratio between the plating efficiencies on wild-type (Ung+) and glycosylase-deficient (Ung-) bacteria ranged from 0.70 to 0.05. If a single-hit dependence of plating efficiency on uracil content is assumed, the probability that any given uracil residue is lethal is approximately 1% (about one-fifth the probability for a pyrimidine dimer). The effect of uracil on recombination was studied in experiments with lambda tandem duplication phages (ethylenediaminetetraacetic acid [EDTA] sensitive), which are converted to single-copy phages (EDTA resistant) by general recombination. For repressed infections (of homoimmune lysogens), recombination was measured by a two-stage assay (DNA extraction, transfection of spheroplasts, and EDTA treatment). The frequencies observed for uracil-containing phages (2 to 4%) were 5 to 10 times higher than control values. However, comparisons with ultraviolet irradiated phages indicated that uracil residues promoted recombination less than 1/100 as efficiently as ultraviolet-induced lesions. Recombination of uracil-containing phages during repressed infections was negligible in recA and partially reduced in recB bacteria. Recombination was very low in ung cells, suggesting that excision repair was responsible for the stimulation. Interestingly, uracil-stimulated recombination was elevated about twofold in xth bacteria.


Assuntos
Bacteriófago lambda/genética , Reparo do DNA , DNA Viral/metabolismo , Recombinação Genética , Uracila/metabolismo , Bacteriófago lambda/crescimento & desenvolvimento , Escherichia coli/genética , Transfecção
15.
Proc Natl Acad Sci U S A ; 75(9): 4125-9, 1978 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-212734

RESUMO

Intracellular lambda DNA (from EDTA-sensitive tandem duplication phages) was extracted from infected rec+ bacteria and scored for infectivity and recombination (loss of duplication) by transfection of recA recB spheroplasts and subsequent assay for EDTA resistance. When phage development was blocked by repressor or by antibiotics (chloramphenicol and/or rifampin), the apparent recombination frequency was about 0.1% above the background value for recA infections. Prior irradiation of the phage greatly stimulated recombination; the frequency was 20% when UV fluence was 140 J/m2. Repair (recovery of infectivity) and recombination of irradiated phage DNA proceeded readily in the presence of chloramphenicol and rifampin. Inhibitors of DNA gyrase (coumermycin and oxolinic acid) blocked repair and reduced recombination. UV-stimulated recombination was very low in recA but nearly normal in recB cells: repair was reduced in both mutant strains. The recombination remained high as phage/cell ratios less than unity.


Assuntos
Colífagos/metabolismo , Reparo do DNA/efeitos dos fármacos , Recombinação Genética/efeitos dos fármacos , Inibidores da Topoisomerase I , Aminocumarinas , Antibacterianos/farmacologia , Cumarínicos/farmacologia , Ácido Oxolínico/farmacologia , Pirróis/farmacologia , Recombinação Genética/efeitos da radiação , Raios Ultravioleta
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