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1.
Dis Esophagus ; 33(1)2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31313807

RESUMO

The positive impact on patient comprehension and improved procedural outcomes when multimedia is utilized to convey instructions preprocedurally has been previously shown for gastrointestinal procedures such as colonoscopy. However, in gastroesophageal reflux testing (GERD), we continue to utilize verbal and written instructions to establish this diagnosis when we use BRAVO pH testing. This is arguably a more complex procedure involving stopping medications, placement of a device, and maintaining an accurate diary for the duration of the testing. We hypothesize that by utilizing multimedia to relay complex textual information, patients will have improved comprehension of periprocedural instructions thereby improving data entry and satisfaction of expectations during the procedure. Prospective randomized study of 120 patients undergoing endoscopic placement of the BRAVO pH monitoring capsule for evaluation of GERD receive either written preoperative instructions (control) or written plus video instructions (video group). A composite comprehension score was calculated using procedure-specific parameters of data entry over the 48-hour monitoring period. Patient satisfaction was evaluated on the basis of a five-point Likert scale. Extent of patient satisfaction was defined by the fulfillment of patient expectations. Exclusion criteria included patients who did not have access to the video or did not complete follow-up. Seventy-eight patients completed all follow-up evaluations. The video group (n = 44) had a significantly higher mean comprehension score when compared to the control group (n = 34) (9.6 ± 1.4 vs. 7.4 ± 2.0, P = 0.01). Overall satisfaction with instructions was significantly higher in the intervention group (91% vs. 47%, p 0.01). We detected no significant difference in comprehension or satisfaction scores in subgroup analyses of the video group comparing patients <65 and ≥65 years of age and by education level. Compared to standard written instructions, video instructions improved patient comprehension based on data evaluation, and satisfaction. Therefore, clinicians should consider incorporation of multimedia instructions to enhance patient periprocedural expectations and understanding of reflux pH testing using the BRAVO procedure.


Assuntos
Monitoramento do pH Esofágico/psicologia , Refluxo Gastroesofágico/diagnóstico , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Educação de Pacientes como Assunto/métodos , Satisfação do Paciente/estatística & dados numéricos , Idoso , Compreensão , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Multimídia , Estudos Prospectivos
2.
J Appl Microbiol ; 122(1): 78-86, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27775827

RESUMO

AIMS: Human norovirus is a major public health burden and is resistant to numerous sanitizers and disinfectants. In this study, we tested the efficacy of an antimicrobial product containing a blend of silver ions and citric acid (silver dihydrogen citrate; SDC) against GI.6 and GII.4 HuNoV. METHODS AND RESULTS: Pure® hard surface disinfectant (Pure Bioscience, El Cajon, CA) was evaluated using ASTM International virucidal suspension and stainless steel carrier assays. The effect of SDC (or citrate alone) exposure on viral integrity was evaluated using RT-qPCR, transmission electron microscopy, sodium dodecyl sulphate-polyacrylamide gel electrophoresis/Western blot analysis and a receptor-binding assay. Suspension assays showed a 4·0 log10 reduction in RNA copy number within 5 min, while carrier assays showed a 2·0-3·0 log10 reduction in 30 min. Incorporating a simulated soil load into the sample matrix significantly reduced product efficacy. Treated particles displayed deformation and aggregation, a 50% reduction in viral capsid protein band intensity, and an 80% reduction in histo-blood group antigen receptor-binding ability. CONCLUSIONS: Our results suggest that SDC acts exclusively on the viral capsid, and shows efficacy against HuNoV when used on precleaned surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: This study sheds light on the mechanisms and efficacy of a novel antimicrobial against HuNoV. Our results suggest: (i) silver ions exclusively target the viral capsid, and not the RNA genome; (ii) citrate is not crucial for HuNoV capsid deformation.


Assuntos
Citratos/farmacologia , Desinfetantes/farmacologia , Norovirus/efeitos dos fármacos , Compostos de Prata/farmacologia , Proteínas do Capsídeo/genética , Humanos , Norovirus/genética , Reação em Cadeia da Polimerase em Tempo Real
3.
Int J Obes (Lond) ; 40(4): 721-4, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26853917

RESUMO

The purpose of this study was to compare the outcomes of patients undergoing cardiac transplantation stratified by body mass index (BMI, kg m(-)(2)). The Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease registry captured 220 cardiac transplantations in Alberta, Canada from January 2004 to April 2013. All recipients were stratified by BMI into five groups (BMI: <20, 20-24.9, 25-29.9, 30-<34.9 and ⩾35). Patient characteristics were analyzed by analysis of variance and χ(2) analyses. Kaplan-Meier was used to examine survival differences. Preoperative characteristics demonstrated significant increases in metabolic syndrome, prior myocardial infarction and prior coronary artery bypass graft in patients with morbid obesity. Intra-operatively, there was an increase in cardiopulmonary bypass time in patients with morbid obesity (P<0.01). Postoperative analysis revealed increased rates of early complications (<30 days), associated with a BMI >35. Long-term survival was also significantly decreased in patients with morbid obesity. Of interest, obesity (BMI, 30-34.9) was not associated with decreased survival. These findings suggest that, post-cardiac transplantation, patients who have a BMI ⩾35 have lower long-term survival compared with all other BMI groups. However, patients with BMI 30-34.9 did not have significantly worse outcomes and should not be excluded for heart transplantation based on BMI.


Assuntos
Doença das Coronárias/fisiopatologia , Transplante de Coração , Infarto do Miocárdio/fisiopatologia , Obesidade Mórbida/complicações , Adulto , Alberta/epidemiologia , Doença das Coronárias/etiologia , Doença das Coronárias/mortalidade , Feminino , Transplante de Coração/mortalidade , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/etiologia , Infarto do Miocárdio/mortalidade , Obesidade Mórbida/mortalidade , Obesidade Mórbida/fisiopatologia , Seleção de Pacientes , Complicações Pós-Operatórias/etiologia , Modelos de Riscos Proporcionais , Medição de Risco , Fatores de Risco , Resultado do Tratamento
4.
Appl Environ Microbiol ; 81(15): 4940-6, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25979897

RESUMO

Human norovirus (HuNoV) represents a significant public health burden worldwide and can be environmentally transmitted. Copper surfaces have been shown to inactivate the cultivable surrogate murine norovirus, but no such data exist for HuNoV. The purpose of this study was to characterize the destruction of GII.4 HuNoV and virus-like particles (VLPs) during exposure to copper alloy surfaces. Fecal suspensions positive for a GII.4 HuNoV outbreak strain or GII.4 VLPs were exposed to copper alloys or stainless steel for 0 to 240 min and recovered by elution. HuNoV genome integrity was assessed by reverse transcription-quantitative PCR (RT-qPCR) (without RNase treatment), and capsid integrity was assessed by RT-qPCR (with RNase treatment), transmission electron microscopy (TEM), SDS-PAGE/Western blot analysis, and a histo-blood group antigen (HBGA) binding assay. Exposure of fecal suspensions to pure copper for 60 min reduced the GII.4 HuNoV RNA copy number by ∼3 log10 units when analyzed by RT-qPCR without RNase treatment and by 4 log10 units when a prior RNase treatment was used. The rate of reduction of the HuNoV RNA copy number was approximately proportional to the percentage of copper in each alloy. Exposure of GII.4 HuNoV VLPs to pure-copper surfaces resulted in noticeable aggregation and destruction within 240 min, an 80% reduction in the VP1 major capsid protein band intensity in 15 min, and a near-complete loss of HBGA receptor binding within 8 min. In all experiments, HuNoV remained stable on stainless steel. These results suggest that copper surfaces destroy HuNoV and may be useful in preventing environmental transmission of the virus in at-risk settings.


Assuntos
Ligas/toxicidade , Capsídeo/efeitos dos fármacos , Cobre/toxicidade , Fezes/virologia , Genoma Viral/efeitos dos fármacos , Norovirus/efeitos dos fármacos , Ligação Viral/efeitos dos fármacos , Western Blotting , Humanos , Microscopia Eletrônica de Transmissão , Norovirus/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa
5.
J Hosp Infect ; 133: 28-37, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36565931

RESUMO

BACKGROUND: Polymerase chain reaction (PCR) is an essential tool for rapid detection of pathogens, but is susceptible to cross-contamination by residual nucleic acid, leading to false-positive results. Adequate surface decontamination would help prevent this, but most protocols target infectious microbes rather than free nucleic acid. The aim of this study was to evaluate the ability of commercial surface disinfectants to degrade different representative classes of nucleic acid. METHODS: Commercial surface disinfectants with various active ingredients, as well as 10% chlorine bleach, were tested. Nucleic acid was dried on to stainless steel coupons and treated with disinfectant for 0-4 min prior to neutralization and quantification by quantitative reverse transcription PCR. The effective disinfectants were also evaluated in the presence of organic load. RESULTS: Only dilute chlorine bleach and the hypochlorite-based commercial disinfectant significantly degraded any type of free nucleic acid. Hydrogen-peroxide- and quaternary-ammonium-based disinfectants gave <1 log reduction after 4 min for all targets. Results were time-dependent for each target, which underscores the importance of adequate contact time. Organic load appeared to have little impact on the efficacy of hypochlorite-based disinfectants for nucleic acid degradation. CONCLUSIONS: This study demonstrates the importance of proper selection and application of disinfectant to remove residual nucleic acid when processing samples for molecular diagnostic testing.


Assuntos
Desinfetantes , Humanos , Ácido Hipocloroso , Cloro , Patologia Molecular , Hipoclorito de Sódio , Desinfecção/métodos
6.
Opt Express ; 20(19): 20874-83, 2012 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-23037211

RESUMO

Target-plane intensities on the short-pulse beamlines of OMEGA EP, a petawatt-class laser, are characterized on-shot using the focal-spot diagnostic (FSD), an indirect wavefront-based measurement. Phase-retrieval methods are employed using on-shot and offline camera-based far-field measurements to improve the wavefront measurements and yield more-accurate, repeatable focal-spot predictions. Incorporation of these techniques has improved the mean cross-correlation between the FSD predictions and direct far-field fluence measurements in the target chamber from 0.78 to 0.94.

7.
J Gen Virol ; 92(Pt 7): 1493-1499, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21471320

RESUMO

The prophylactic use of topical antiviral agents has recently been validated by the reduction in human immunodeficiency virus (HIV) type 1 infection incidence seen using tonofovir-containing microbicides. In order to develop a wide-spectrum microbicide to prevent infection with a wide range of sexually transmitted viruses, we have previously reported the development of HIV-neutralizing aptamers and here report the isolation and characterization of aptamers that neutralize herpes simplex virus type 2 (HSV-2). These aptamers bind the envelope glycoprotein (gD), are potent (IC(50) of 20-50 nM) and are able to block infection pathways dependent on both major entry receptors, Nectin1 and HVEM. Structural analysis and mutagenesis of these aptamers reveal a core specificity element that could provide the basis for pharmaceutical development. As HSV-2 is a major risk factor for the acquisition of HIV-1, a microbicide capable of preventing HSV-2 infection would not only reduce the morbidity associated with HSV-2, but also that derived from HIV-1.


Assuntos
Antivirais/farmacologia , Aptâmeros de Nucleotídeos/farmacologia , Herpes Simples/virologia , Herpesvirus Humano 2/efeitos dos fármacos , Animais , Antivirais/química , Aptâmeros de Nucleotídeos/química , Sequência de Bases , Moléculas de Adesão Celular/metabolismo , Herpes Simples/tratamento farmacológico , Herpesvirus Humano 1/efeitos dos fármacos , Herpesvirus Humano 1/genética , Herpesvirus Humano 1/fisiologia , Herpesvirus Humano 2/genética , Herpesvirus Humano 2/fisiologia , Humanos , Dados de Sequência Molecular , Nectinas
8.
Neurobiol Learn Mem ; 93(3): 383-7, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20018248

RESUMO

The GABA(A)R alpha4 subunit is highly expressed in the dentate gyrus region of the hippocampus at predominantly extra synaptic locations where, along with the GABA(A)R delta subunit, it forms GABA(A) receptors that mediate a tonic inhibitory current. The present study was designed to test hippocampus-dependent and hippocampus-independent learning and memory in GABA(A)R alpha4 subunit-deficient mice using trace and delay fear conditioning, respectively. Mice were of a mixed C57Bl/6J X 129S1/X1 genetic background from alpha4 heterozygous breeding pairs. The alpha4-knockout mice showed enhanced trace and contextual fear conditioning consistent with an enhancement of hippocampus-dependent learning and memory. These enhancements were sex-dependent, similar to previous studies in GABA(A)R delta knockout mice, but differences were present in both males and females. The convergent findings between alpha4 and delta knockout mice suggests that tonic inhibition mediated by alpha4betadelta GABA(A) receptors negatively modulates learning and memory processes and provides further evidence that tonic inhibition makes important functional contributions to learning and behavior.


Assuntos
Condicionamento Psicológico , Medo , Receptores de GABA-A/deficiência , Receptores de GABA-A/genética , Reforço Psicológico , Animais , Giro Denteado/metabolismo , Feminino , Hipocampo/metabolismo , Aprendizagem/fisiologia , Masculino , Memória/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
9.
Science ; 229(4713): 519-24, 1985 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-4023698

RESUMO

Hemocyanins are large multi-subunit copper proteins that transport oxygen in many arthropods and molluscs. Comparison of the amino acid sequence data for seven different subunits of arthropod hemocyanins from crustaceans and chelicerates shows many highly conserved residues and extensive regions of near identity. This correspondence can be matched closely with the three domain structure established by x-ray crystallography for spiny lobster hemocyanin. The degree of identity is particularly striking in the second domain of the subunit that contains the six histidines which ligate the two oxygen-binding copper atoms. The polypeptide architecture of spiny lobster hemocyanin appears to be the same in all arthropods. This structure must therefore be at least as old as the estimated time of divergence of crustaceans and chelicerates, about 540 to 600 million years ago.


Assuntos
Artrópodes , Hemocianinas , Sequência de Aminoácidos , Animais , Aracnídeos/genética , Artrópodes/genética , Sítios de Ligação , Evolução Biológica , Fenômenos Químicos , Química , Cobre , Crustáceos/genética , Hemocianinas/genética , Modelos Moleculares , Conformação Proteica , Especificidade da Espécie
10.
J Clin Invest ; 103(11): 1509-15, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10359560

RESUMO

Prostacyclin synthase (PGIS) is the final committed enzyme in the metabolic pathway leading to prostacyclin (PGI2) production. Patients with severe pulmonary hypertension have a PGIS deficiency of their precapillary vessels, but the importance of this deficiency for lung vascular remodeling remains unclear. We hypothesized that selective pulmonary overexpression of PGIS may prevent the development of pulmonary hypertension. To study this hypothesis, transgenic mice were created with selective pulmonary PGIS overexpression using a construct of the 3.7-kb human surfactant protein-C (SP-C) promoter and the rat PGIS cDNA. Transgenic mice (Tg+) and nontransgenic littermates (Tg-) were subjected to a simulated altitude of 17,000 ft for 5 weeks, and right ventricular systolic pressure (RVSP) was measured. Histology was performed on the lungs. The Tg+ mice produced 2-fold more pulmonary 6-keto prostaglandin F1alpha (PGF1alpha) levels than did Tg- mice. After exposure to chronic hypobaric hypoxia, Tg+ mice have lower RVSP than do Tg- mice. Histologic examination of the lungs revealed nearly normal arteriolar vessels in the Tg+ mice in comparison with vessel wall hypertrophy in the Tg- mice. These studies demonstrate that Tg+ mice were protected from the development of pulmonary hypertension after exposure to chronic hypobaric hypoxia. We conclude that PGIS plays a major role in modifying the pulmonary vascular response to chronic hypoxia. This has important implications for the pathogenesis and treatment of severe pulmonary hypertension.


Assuntos
Sistema Enzimático do Citocromo P-450/fisiologia , Hipertensão Pulmonar/prevenção & controle , Hipóxia/fisiopatologia , Oxirredutases Intramoleculares/fisiologia , Pulmão/irrigação sanguínea , Animais , Sequência de Bases , Sistema Enzimático do Citocromo P-450/biossíntese , Sistema Enzimático do Citocromo P-450/genética , DNA Complementar , Epitélio , Feminino , Expressão Gênica , Humanos , Hipertensão Pulmonar/fisiopatologia , Oxirredutases Intramoleculares/biossíntese , Oxirredutases Intramoleculares/genética , Pulmão/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Dados de Sequência Molecular , Policitemia/fisiopatologia , Artéria Pulmonar/fisiopatologia , Ratos
11.
J Leukoc Biol ; 50(4): 412-22, 1991 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1655939

RESUMO

Tetrandrine is an alkaloid obtained from the root of a medicinal herb which is employed in China as a treatment for silicosis. One proposed mechanism for the development of silica-induced fibrosis is lung damage resulting from particle-induced inflammation and secretion of reactive compounds from alveolar phagocytes. Therefore, the objective of the present study was to determine if tetrandrine exhibited the ability to inhibit respiratory burst activity of pulmonary phagocytes. The data indicate that although tetrandrine is not cytotoxic to phagocytic cells, it is a potent inhibitor in vitro of zymosan-stimulated oxygen consumption, superoxide anion release, and hydrogen peroxide secretion by alveolar macrophages. Tetrandrine is also effective in vivo in preventing activation of alveolar macrophages after inhalation or intratracheal instillation of silica. Tetrandrine also inhibits stimulant-induced chemiluminescence by polymorphonuclear leukocytes. Since tetrandrine does not alter stimulant-induced depolarization of phagocytic cells, its inhibitory action is not via interference with receptor-ligand binding but rather must occur elsewhere in the stimulus-secretion coupling scheme.


Assuntos
Alcaloides/farmacologia , Anti-Inflamatórios não Esteroides/farmacologia , Benzilisoquinolinas , Fagócitos/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Animais , Peróxido de Hidrogênio/metabolismo , Medições Luminescentes , Masculino , Neutrófilos/efeitos dos fármacos , Neutrófilos/fisiologia , Consumo de Oxigênio/efeitos dos fármacos , Fagócitos/metabolismo , Fagócitos/fisiologia , Fagocitose/fisiologia , Ratos , Ratos Endogâmicos , Superóxidos/metabolismo , Zimosan/farmacologia
12.
Gene ; 70(1): 139-51, 1988 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-3266489

RESUMO

The 5-aminolevulinate synthase gene (hemA) from Rhizobium meliloti was used to probe a genomic lambda bank derived from Rhodobacter sphaeroides DNA. Two phage clones were found to bear homology to the Rhizobium probe. Southern hybridization analysis of the two lambda phage clones, which we designated lambda Hem 10 and lambda Hem 12, showed that the homology to the Rhizobium hemA gene was localized to a 3.1-kb SalI fragment derived from lambda Hem 10 and a 7.0-kb SalI fragment derived from lambda Hem 12. Each of the SalI fragments was subsequently cloned into the multiple cloning site of pUC19 in both orientations relative to the lac promoter. Restriction analysis confirmed that each SalI fragment was unique. It was also shown from Southern hybridization analysis that the regions of homology within each of the R. sphaeroides restriction fragments and the Rhizobium probe were different. Further, we have tentatively concluded that each R. sphaeroides hemA gene shows a relatively low degree of homology to the other. Data obtained from in vitro transcription-translation studies in a homologous R. sphaeroides cell-free system, and complementation of hemA mutations of both Escherichia coli and R. sphaeroides by either of the putative hemA clones suggested the presence of a gene encoding 5-aminolevulinate synthase on each DNA sequence. The fact that 5-aminolevulinate synthase activity could be demonstrated in mutant strains complemented in trans with either cloned DNA fragment further supported this conclusion.


Assuntos
5-Aminolevulinato Sintetase/genética , Clonagem Molecular , DNA Bacteriano/genética , Genes Bacterianos , Rhodobacter sphaeroides/genética , Sequência de Bases , Cosmídeos , Hibridização de Ácido Nucleico , Plasmídeos , Mapeamento por Restrição , Transformação Bacteriana
13.
Oncol Nurs Forum ; 17(3): 403-7, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2342974

RESUMO

Though therapeutic advances have been made in the treatment of ovarian carcinoma, success at achieving a cure in women with advanced disease has been elusive. Since advanced ovarian carcinoma is frequently confined to the peritoneum, the use of intraperitoneal (IP) chemotherapy is being studied. Dose-limiting toxicity and extended nausea and vomiting associated with intraperitoneal chemotherapy are problems with several of the drugs under study. The most beneficial drug for intraperitoneal use would be one that offers the maximum pharmacologic value without toxicity. An investigation at the Dartmouth-Hitchcock Medical Center in New Hampshire is exploring the use of alpha interferon in treating advanced ovarian carcinoma. This case report describes an individual's course of treatment and the challenges in managing the administration of the IP immunotherapy, anticipating problems, and identifying interventions necessary to achieving optimal patient comfort during this Phase I-II investigation.


Assuntos
Interferon Tipo I/uso terapêutico , Neoplasias Ovarianas/terapia , Cateteres de Demora , Avaliação de Medicamentos , Feminino , Humanos , Injeções Intraperitoneais , Interferon Tipo I/administração & dosagem , Interferon Tipo I/efeitos adversos , Pessoa de Meia-Idade , Neoplasias Ovarianas/enfermagem , Planejamento de Assistência ao Paciente
17.
Artigo em Inglês | MEDLINE | ID: mdl-1964388

RESUMO

Screening has played a major role in decreasing the morbidity and mortality associated with carcinoma of the cervix. Aggressive management of lesions recognized as precursor to invasive squamous carcinoma, (cervical intraepithelial neoplasia), has markedly reduced the incidence of invasive cancer. Squamous carcinomas constitute most of the cervical cancers. The relationship between human papilloma virus and cervical abnormalities is reviewed. Nursing diagnoses and care planning ideas are discussed.


Assuntos
Carcinoma de Células Escamosas/prevenção & controle , Programas de Rastreamento/métodos , Papillomaviridae , Infecções Tumorais por Vírus/prevenção & controle , Doenças do Colo do Útero/prevenção & controle , Displasia do Colo do Útero/prevenção & controle , Neoplasias do Colo do Útero/prevenção & controle , Carcinoma de Células Escamosas/etiologia , Árvores de Decisões , Feminino , Humanos , Infecções Tumorais por Vírus/complicações , Infecções Tumorais por Vírus/enfermagem , Doenças do Colo do Útero/complicações , Doenças do Colo do Útero/enfermagem , Displasia do Colo do Útero/complicações , Displasia do Colo do Útero/enfermagem , Neoplasias do Colo do Útero/etiologia , Esfregaço Vaginal
18.
J Bacteriol ; 174(5): 1505-14, 1992 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1537795

RESUMO

We have identified intrinsic high-level resistance (HLR) to tellurite, selenite, and at least 15 other rare-earth oxides and oxyanions in the facultative photoheterotroph Rhodobacter sphaeroides grown either chemoheterotrophically or photoheterotrophically. Other members of the class Proteobacteria, including members of the alpha-2 and alpha-3 phylogenetic subgroups, were also shown to effect the reduction of many of these compounds, although genera from the alpha-1, beta-1, and gamma-3 subgroups did not express HLR to the oxyanions examined. Detailed analyses employing R. sphaeroides have shown that HLR to at least one class of these oxyanions, the tellurite class (e.g., tellurate, tellurite, selenate, selenite, and rhodium sesquioxide), occurred via intracellular oxyanion reduction and resulted in deposition of metal in the cytoplasmic membrane. The concomitant evolution of hydrogen gas from cells grown photoheterotrophically in the presence of these oxyanions was also observed. HLR to tellurite class oxyanions in R. sphaeroides was not affected by exogenous methionine or phosphate but was reduced 40-fold by the addition of cysteine to growth media. In contrast HLR to the periodate class oxyanions (e.g., periodate, siliconate, and siliconite) was inhibited by extracellular PO4(3-) but did not result in metal deposition or gas evolution. Finally, we observed that HLR to arsenate class oxyanions (e.g., arsenate, molybdate, and tungstate) occurred by a third, distinct mechanism, as evidenced by the lack of intracellular metal deposition and hydrogen gas evolution and an insensitivity to extracellular PO4(3-) or cysteine. Examination of a number of R. sphaeroides mutants has determined the obligate requirement for an intact CO2 fixation pathway and the presence of a functional photosynthetic electron transport chain to effect HLR to K2TeO3 under photosynthetic growth conditions, whereas functional cytochromes bc1 and c2 were required under aerobic growth conditions to facilitate HLR. Finally, a purification scheme to recover metals from intact bacterial cells was developed.


Assuntos
Bactérias/metabolismo , Resistência Microbiana a Medicamentos , Metais Terras Raras/metabolismo , Ânions , Bactérias/efeitos dos fármacos , Hidrogênio/metabolismo , Metais Terras Raras/toxicidade , Mutação , Oxirredução , Oxirredutases/metabolismo , Ródio/metabolismo , Ródio/toxicidade , Selênio/metabolismo , Selênio/toxicidade , Frações Subcelulares/metabolismo , Telúrio/metabolismo , Telúrio/toxicidade
19.
Agents Actions ; 37(3-4): 158-61, 1992 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-1295358

RESUMO

Hartley or Dunkin-Hartley guinea pigs (n = 136) were actively sensitized to ovalbumin or Ascaris suum protein by five different regimes. Specific airway resistance (sR(AW)) was measured in conscious animals by a plethysmographic procedure before, immediately following and at various intervals (up to 96 h) after aerosolized antigen or vehicle challenge. Each sensitization and challenge regime produced an immediate allergic response with positive responses (defined as a 2-fold increase in sR(AW)) in 78-100% of animals. Recovery from the immediate response followed by late-phase responses was observed in only two out of a group of four animals. The results failed to substantiate literature reports of a high incidence of late responses in the guinea pig at 4-8, 17-24 or 72 h after allergen challenge.


Assuntos
Obstrução das Vias Respiratórias/imunologia , Antígenos/imunologia , Hipersensibilidade Respiratória/imunologia , Aerossóis , Obstrução das Vias Respiratórias/fisiopatologia , Animais , Ascaris/imunologia , Cobaias , Masculino , Ovalbumina/imunologia , Pletismografia , Testes de Função Respiratória , Hipersensibilidade Respiratória/fisiopatologia
20.
J Bacteriol ; 171(8): 4385-94, 1989 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-2546920

RESUMO

We have constructed a suicide vector, pU1800, containing the transposable element TnphoA (Tn5 IS50L::phoA), for the purpose of producing protein fusions in vivo between the Escherichia coli alkaline phosphatase (APase) and proteins of the facultative photoheterotroph, Rhodobacter sphaeroides. We introduced TnphoA into the genome of R. sphaeroides at a coupled conjugation-transposition frequency of approximately 1 x 10(-6). Fusions giving rise to APase expression, as judged by blue-colony pigmentation when exconjugants were plated on growth medium containing the chromogenic indicator 5-bromo-4-chloro-3-indolyl phosphate, were observed in about 1% of the exconjugants. Numerous, distinguishable mutant phenotypes have been generated by this method, including those which lack the ability to use dimethyl sulfoxide as a terminal electron acceptor during anaerobic respiration, as well as those which are photosynthetically incompetent or altered in pigment synthesis, and others that express resistance to chlorate. The growth and spectral characteristics of several of these mutants, as well as the localization and quantitation of subcellular APase activity under different physiological conditions, have been examined. The presence of TnphoA in the host genome has been confirmed for each mutant analyzed, and specifically tagged DNA fragments containing TnphoA have been identified and localized; cosmids containing R. sphaeroides genomic DNA capable of complementing individual mutants have also been isolated. The usefulness of this approach in studying gene activity in R. sphaeroides is discussed.


Assuntos
Elementos de DNA Transponíveis , Dimetil Sulfóxido/metabolismo , Genes Bacterianos , Vetores Genéticos , Glucose/metabolismo , Mutação , Consumo de Oxigênio , Rhodobacter sphaeroides/genética , Fosfatase Alcalina/genética , Anaerobiose , Clonagem Molecular , Conjugação Genética , Escuridão , Escherichia coli/enzimologia , Escherichia coli/genética , Fotossíntese , Mapeamento por Restrição , Rhodobacter sphaeroides/crescimento & desenvolvimento , Rhodobacter sphaeroides/metabolismo
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