Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
1.
Public Health ; 197: 11-18, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34271270

RESUMO

OBJECTIVES: Falls in older adults cause significant morbidity and mortality and incur cost to health and care services. The Falls Management Exercise (FaME) programme is a 24-week intervention for older adults that, in clinical trials, improves balance and functional strength and leads to fewer falls. Similar but more modest outcomes have been found when FaME is delivered in routine practice. Understanding the degree to which the programme is delivered with fidelity is important if 'real-world' delivery of FaME is to achieve the same magnitude of outcome as in clinical trials. The objective of this study was to examine the implementation fidelity of FaME when delivered in the community to inform quality improvement strategies that maximise programme effectiveness. STUDY DESIGN: A mixed methods implementation study of FaME programme delivery. METHODS: Data from programme registers, expert observations of FaME classes, and semistructured interviews with FaME instructors were triangulated using a conceptual framework for implementation fidelity. Quantitative data were analysed using descriptive statistics. Interviews were transcribed verbatim and analysed using thematic analysis. RESULTS: In total, 356 participants enrolled on 29 FaME programmes, and 143 (40%) participants completed at least 75% of the classes within a programme. Observations showed that 72%-78% of programme content was delivered, and 80%-84% quality criteria were met. Important content that was most often left out included home exercises, Tai Chi moves, and floor work, whereas quality items most frequently missed out included asking about falls in the previous week, following up attendance absence and explaining the purpose of exercises. Only 24% of class participants made the expected strength training progression. Interviews with FaME instructors helped explain why elements of programme content and quality were not delivered. Strategies for improving FaME delivery were established and helped to maintain quality and fidelity. CONCLUSIONS: FaME programmes delivered in the 'real world' can be implemented with a high degree of fidelity, although important deviations were found. Facilitation strategies could be used to further improve programme fidelity and maximise participant outcomes.


Assuntos
Exercício Físico , Treinamento Resistido , Idoso , Terapia por Exercício , Humanos , Avaliação de Programas e Projetos de Saúde
2.
Inj Prev ; 22(5): 334-41, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-26826177

RESUMO

BACKGROUND: Childhood falls, poisonings and scalds, occurring predominantly in the home, are an important public health problem, yet there is limited evidence on the costs of these injuries to individuals and society. OBJECTIVES: To estimate National Health Service (NHS) and child and family costs of falls, poisonings and scalds. METHODS: We undertook a multicentre longitudinal study of falls, poisonings and scalds in children under 5 years old, set in acute NHS Trusts across four UK study centres. Data from parental self-reported questionnaires on health service resource use, family costs and expenditure were combined with unit cost data from published sources to calculate average cost for participants and injury mechanism. RESULTS: 344 parents completed resource use questionnaires until their child recovered from their injury or until 12 months, whichever came soonest. Most injuries were minor, with >95% recovering within 2 weeks, and 99% within 1 month of the injury. 61% emergency department (ED) attendees were not admitted, 35% admitted for ≤1 day and 4% admitted for ≥2 days. The typical healthcare cost of an admission for ≥2 days was estimated at £2000-3000, for an admission for ≤1 day was £700-1000 and for an ED attendance without admission was £100-180. Family costs were considerable and varied across injury mechanisms. Of all injuries, scalds accrued highest healthcare and family costs. CONCLUSIONS: Falls, poisonings and scalds incur considerable short-term healthcare and family costs. These data can inform injury prevention policy and commissioning of preventive services.


Assuntos
Acidentes por Quedas/economia , Acidentes Domésticos/economia , Queimaduras/economia , Hospitalização/economia , Tempo de Internação/economia , Intoxicação/economia , Medicina Preventiva , Acidentes por Quedas/prevenção & controle , Acidentes por Quedas/estatística & dados numéricos , Acidentes Domésticos/prevenção & controle , Queimaduras/prevenção & controle , Queimaduras/reabilitação , Pré-Escolar , Inglaterra/epidemiologia , Feminino , Custos de Cuidados de Saúde , Hospitalização/estatística & dados numéricos , Humanos , Lactente , Recém-Nascido , Tempo de Internação/estatística & dados numéricos , Estudos Longitudinais , Masculino , Pais , Intoxicação/prevenção & controle , Intoxicação/reabilitação , Formulação de Políticas , Medicina Preventiva/economia , Medicina Preventiva/métodos , Inquéritos e Questionários
3.
Perspect Public Health ; : 17579139231185999, 2023 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-37572017

RESUMO

AIMS: Unintentional injuries in the home contribute substantially to preschool child morbidity and mortality. Practitioners such as health visitors, family mentors and children's centre staff are well-positioned to facilitate child injury prevention by providing home safety advice to families, and training may enhance their ability to do so. We aimed to assess the impact of child home safety training for these practitioners. METHODS: An explanatory mixed-methods design was used. Practitioners completed questionnaires before, and up to 7 months after, receiving child home safety training and took part in interviews. Seventy-eight health visitors, 72 family mentors and 11 children's centre staff members completed questionnaires. Items were used to calculate scores on home safety knowledge, confidence to provide home safety advice and belief that child home safety promotion is important. Thematic analysis of interviews with seven health visitors and nine family mentors, open-ended responses to the questionnaires and an additional evaluation form was conducted to explore attendees' perceptions of the training and its impact. In addition, seven health visitors and six children's centre staff who had received no training were interviewed. RESULTS: Knowledge was greater post-training than pre-training across all participants (p < .001). When practitioner groups were analysed separately, there were significant increases in family mentors' knowledge (p < .001) and belief (p = .016), and health visitors' confidence (p = .0036). Qualitative findings indicated that most training session attendees valued the training, believed their practice relating to child home safety had improved as a result, and felt further similar training sessions would be beneficial. Those who had not attended the sessions described a need for more child home safety training. CONCLUSIONS: Delivering training to practitioners providing child home safety promotion to families with preschool children can enhance injury prevention knowledge, beliefs and confidence and positively impact on home safety promotion by practitioners.

4.
Cancer Res ; 55(13): 2723-6, 1995 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-7796393

RESUMO

Asbestos causes persistent increases in c-jun mRNA and AP-1 DNA binding activity in hamster tracheal epithelial (HTE) cells, the progenitor cell type of asbestos-induced bronchogenic carcinoma. Studies here were designed to determine mechanisms of c-jun induction by asbestos and the phenotypic consequences of Jun expression in HTE cells. To examine whether asbestos or H2O2 induced transcription of c-jun, we transiently transfected HTE cells with a plasmid containing a fragment of the c-jun promoter coupled to a luciferase reporter gene. In addition, c-jun was overexpressed in cells using a full-length human c-jun construct, and effects on proliferation and transformation were examined. HTE cells transfected with the jun-luciferase construct showed increased luciferase activity when exposed to crocidolite asbestos or H2O2. These results demonstrate that asbestos and H2O2 activate AP-1-dependent gene transcription. Overexpression of c-jun led to increased proliferation and enhanced ability of HTE cells to grow in soft agar, an indication of cellular transformation. Data suggest that overexpression of c-jun may contribute to asbestos and oxidant-induced proliferation and carcinogenesis.


Assuntos
Amianto/farmacologia , Transformação Celular Neoplásica/genética , Genes jun , Peróxido de Hidrogênio/farmacologia , Traqueia/química , Animais , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Cricetinae , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Técnicas In Vitro , Regiões Promotoras Genéticas , Proto-Oncogene Mas , RNA Mensageiro/genética , Transcrição Gênica/efeitos dos fármacos
5.
Cancer Res ; 61(5): 1791-5, 2001 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-11280724

RESUMO

Crystalline silica has been classified as a group 1 human carcinogen in the lung. However, its mechanisms of action on pulmonary epithelial cells which give rise to lung cancers are unclear. Using a nontransformed alveolar type II epithelial cell line (C10), we show that alpha-quartz silica causes persistent dose-related increases in phosphorylation of c-Jun-NH2-terminal amino kinases (JNKs) that are inhibited by antioxidants (P < or = 0.05). Increases in activator protein-1 (AP-1) binding to DNA and transactivation of AP-1-dependent gene expression by silica were accompanied by increases in steady-state mRNA levels of the AP-1 family members, c-jun, junB, fra-1, and c-fos at 8 h and elevated mRNA levels of fra-1 at 24 h (P < or = 0.05). Addition of tetramethylthiourea inhibited silica-associated increases infra-1 and proportions of cells in S-phase (P < or = .05). Our findings indicate that silica induces JNK activity, AP-1-dependent gene expression, ie., fra-1, and DNA synthesis via oxidative stress. Moreover, they suggest that silica may act mechanistically as a mitogen or tumor promoter, rather than a genotoxic carcinogen, in the development of lung cancers.


Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Estresse Oxidativo/fisiologia , Proteínas Proto-Oncogênicas c-fos/biossíntese , Alvéolos Pulmonares/efeitos dos fármacos , Fase S/efeitos dos fármacos , Dióxido de Silício/toxicidade , Tioureia/análogos & derivados , Animais , Linhagem Celular , DNA/metabolismo , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Sequestradores de Radicais Livres/farmacologia , Radical Hidroxila/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Fosforilação/efeitos dos fármacos , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-fos/genética , Alvéolos Pulmonares/citologia , Alvéolos Pulmonares/metabolismo , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Dióxido de Silício/antagonistas & inibidores , Tioureia/farmacologia , Fator de Transcrição AP-1/metabolismo
6.
Cancer Res ; 57(15): 3101-5, 1997 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-9242432

RESUMO

Asbestos and the phorbol ester tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), increase c-fos and c-jun mRNA levels and AP-1 DNA binding activity in rat pleural mesothelial (RPM) cells, a target cell of asbestos-induced mesotheliomas (N. H. Heintz et al., Proc. Natl. Acad. Sci. USA, 90: 3299-3303, 1993). Because protein kinase C (PKC) is the intracellular receptor of phorbol ester tumor promoters and asbestos is a putative tumor promoter in the respiratory tract, we hypothesized that PKC might play a critical role in asbestos-induced cell signaling pathways associated with regulation of proto-oncogenes. Using a panel of PKC antibodies, we identified PKC alpha as the major PKC isozyme in RPM cells. We then pretreated cells with phorbol ester dibutyrate to down-modulate PKC or with calphostin C, a specific PKC inhibitor, to determine if depletion of PKC alpha could block asbestos-induced c-fos/c-jun expression. Quantitation of Northern blots showed that fiber-associated c-fos/c-jun mRNA levels were significantly lower either after PKC alpha down-modulation or pretreatment with calphostin C. In addition, to determine whether tyrosine kinases also were involved in proto-oncogene activation by asbestos, tyrphostin AG82 or herbimycin A was added to RPM cells before exposure to asbestos. These inhibitors decreased crocidolite-induced c-fos but not c-jun levels, suggesting that tyrosine kinases have different regulatory roles in asbestos-induced c-fos versus c-jun signaling pathways. The ability to block induction of asbestos-induced proto-oncogene expression using pharmacological intervention may be important in prevention and treatment of asbestos-induced proliferative diseases including lung cancers, mesothelioma, and pulmonary fibrosis.


Assuntos
Amianto/farmacologia , Epitélio/enzimologia , Proteína Quinase C/fisiologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Proteínas Proto-Oncogênicas c-jun/metabolismo , Animais , Benzoquinonas , Epitélio/efeitos dos fármacos , Expressão Gênica , Isoenzimas , Lactamas Macrocíclicas , Naftalenos/farmacologia , Dibutirato de 12,13-Forbol/farmacologia , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-fos/genética , Proteínas Proto-Oncogênicas c-jun/genética , Quinonas/farmacologia , RNA Mensageiro/análise , Ratos , Ratos Endogâmicos F344 , Rifabutina/análogos & derivados , Fatores de Tempo
7.
Cancer Res ; 58(20): 4543-7, 1998 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-9788597

RESUMO

Numerous epidemiological studies have demonstrated a positive association between ambient air pollution and adverse health effects including respiratory morbidity, asthma, and lung cancer. It has been suggested in some experimental studies that airborne particulate matter (PM) can produce inflammatory effects, but nothing is known about the possible proliferative and carcinogenic effects of these particles on cells of the lung. We show here that exposure of pulmonary epithelial cells, a cell type affected in acute lung injury, asthma, and lung carcinomas, to nontoxic concentrations of PM in vitro results in increases in c-jun kinase activity, levels of phosphorylated cJun immunoreactive protein, and transcriptional activation of activator protein-1-dependent gene expression. These changes are accompanied by elevations in numbers of cells incorporating 5'-bromodeoxyuridine, a marker of unscheduled DNA synthesis and/or cell proliferation. Data here are the first to demonstrate that interaction of ambient PM with target cells of the lung initiates a cell signaling cascade related causally to aberrant cell proliferation and carcinogenesis.


Assuntos
Poluição do Ar/efeitos adversos , Proteínas Quinases Dependentes de Cálcio-Calmodulina/fisiologia , DNA/biossíntese , Pulmão/metabolismo , Proteínas Quinases Ativadas por Mitógeno , Animais , Bromodesoxiuridina/metabolismo , Divisão Celular , Ativação Enzimática , Células Epiteliais/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno , Fosforilação , Ratos , Fator de Transcrição AP-1/fisiologia
8.
Oncogene ; 7(10): 2059-64, 1992 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1408147

RESUMO

Using a subtractive cDNA approach we have identified a gene, PC326, expressed in 13 of 14 murine plasmacytoma cell lines, but not in any B- or pre-B-lymphoma cell lines. It expresses 4.6-kb and 5.2-kb mRNAs that encode a 747 amino acid protein containing two highly acidic domains flanking a novel, moderately acidic 20 amino acid sequence that is repeated 7.5 times. Sequence comparison identifies an additional 43 amino acid domain that is homologous to a repeated sequence found in the members of the beta-transducin gene family. The PC326 mRNA is detectable in testis but in no other murine tissues, including plasma cells induced by lipopolysaccharide stimulation of splenocytes. Somatic cell hybrids derived from plasmacytomas and fibroblast or T-cell lines have a fibroblastic or T-cell phenotype respectively. Unlike B-cell-specific genes (e.g. immunoglobulin), the expression of which is extinguished in these hybrids, PC326 mRNA appears to be irreversibly turned on in these hybrids. Since PC326 is not expressed in normal plasma cells, it appears that its expression is a cause or consequence of the tumorigenic process that generates murine plasmacytomas.


Assuntos
DNA/isolamento & purificação , Expressão Gênica , Oncogenes , Plasmócitos/química , Plasmocitoma/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Linhagem Celular , DNA/análise , DNA/química , Células Híbridas , Masculino , Camundongos , Dados de Sequência Molecular , RNA Mensageiro/análise , Sequências Repetitivas de Ácido Nucleico , Testículo/química
9.
Curr Top Microbiol Immunol ; 166: 141-7, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2073792

RESUMO

We have combined subtractive cDNA and PCR technologies to construct and analyze a plasmacytoma minus a highly differentiated B lymphoma subtractive cDNA library. We detected no plasmacytoma-specific clones by hybridization with differential cDNA probes or the subtractive insert. However, random selection of 115 clones has identified 16 quantitatively subtractive and 39 qualitatively subtractive clones. From these clones we have identified 8 potentially interesting genes. One quantitatively subtractive clone (clone 315) identifies an mRNA that is expressed in most plasmacytoma cell lines, but is expressed at an approximately 10-fold lower level in B and pre-B lymphoma cell lines; preliminary evidence suggests that the expression of this gene is increased by IL-6. From the 31 unrelated qualitatively subtractive clones, we have identified two classes of genes that are expressed in one or none of 8 B lymphomas examined: 1) those expressed in most plasmacytoma and pre-B lymphoma cell lines (clone 70 and clone 260); and 2) those expressed in most plasmacytoma cell lines, but not in any of the ten pre-B lymphomas examined (clones 251, 289A, 289B, 326, 291).


Assuntos
Linfoma de Células B/genética , Oncogenes , Plasmocitoma/genética , Animais , DNA/análise , Expressão Gênica , Camundongos , RNA Mensageiro/análise , Células Tumorais Cultivadas
10.
Gene ; 150(2): 345-50, 1994 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-7821804

RESUMO

Using a subtractive cDNA approach we have identified two nearly identical genes, Xlr3a and Xlr3b (X-linked lymphocyte regulated), expressed at a consistently high level in 14 out of 14 murine plasmacytoma cell lines, at a high level in 1 out of 8 B-lymphoma cell lines, and at a very low level in 2 out of the 8 B-lymphoma cell lines. The messages are not detected in 10 pre-B-lymphoma cell lines. These genes express 2.0-kb mRNAs that encode 226-amino-acid proteins that are extremely basic, with an estimated pI of 8.1 and 9.0, respectively. By sequence comparison they are homologous to Xlr1, an acidic nuclear protein that is produced in lymphoid cell lines corresponding to the late stages of lymphocyte differentiation. Xlr2 is a highly homologous gene that is expressed in differentiating male germ cells. Xlr3a and Xlr3b are members of a new subfamily in the Xlr multigene family. Like Xlr1, they are up-regulated during B-cell terminal differentiation in normal and neoplastic B-cells, and cross-hybridize with a message in testis RNA. Also, like Xlr1, they do not cross-hybridize with human genomic DNA.


Assuntos
Camundongos/genética , Família Multigênica , Proteínas Nucleares/genética , Cromossomo X , Sequência de Aminoácidos , Animais , Sequência de Bases , Linhagem Celular , Mapeamento Cromossômico , Clonagem Molecular , Cruzamentos Genéticos , DNA Complementar , Expressão Gênica , Marcadores Genéticos , Humanos , Linfoma de Células B , Dados de Sequência Molecular , Muridae , Proteínas Nucleares/biossíntese , Plasmocitoma , RNA Mensageiro/biossíntese , Homologia de Sequência de Aminoácidos , Transfecção , Células Tumorais Cultivadas
11.
Free Radic Biol Med ; 31(12): 1560-9, 2001 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-11744330

RESUMO

Old age is associated with a higher prevalence of cardiovascular disease and diabetes mellitus. Vascular smooth muscle cells (VSMC) play a role in the pathogenesis of vascular diseases, often a complication of diabetes mellitus. We examined in explanted aortic VSMC from young vs. older rats glucose-related activation of nuclear factor kappaB (NF-kappaB), a transcription factor induced by many oxidants. Data demonstrate that old age is associated with enhanced NF-kappaB activity in unstimulated VSMC that is further increased after exposure to high glucose medium. Furthermore, VSMC from old animals exhibit increased levels of protein carbonyls, an indicator of oxidative stress, and less apoptosis in response to glucose than VSMC isolated from young animals. These changes are accompanied by increased expression of NF-kappaB-related genes, gamma-glutamylcysteine synthetase, inhibitor of apoptosis protein-1 (IAP-1), and inducible nitric oxide synthase (iNOS). Results suggest that high glucose, a putative oxidative stress, causes apoptosis in VSMC from young animals and is associated with greater induction of NF-kappaB in VSMC from older animals. Increases in IAP-1 and decreased apoptosis implicate NF-kappaB as a survival factor in VSMC.


Assuntos
Apoptose , Senescência Celular/fisiologia , Glucose/farmacologia , Músculo Liso Vascular/efeitos dos fármacos , Animais , Aorta/citologia , Glutamato-Cisteína Ligase/biossíntese , Glutamato-Cisteína Ligase/genética , Proteínas Inibidoras de Apoptose , Masculino , Músculo Liso Vascular/citologia , Músculo Liso Vascular/metabolismo , NF-kappa B/metabolismo , Óxido Nítrico Sintase/biossíntese , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase Tipo II , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Biossíntese de Proteínas , Proteínas/genética , Ratos
12.
Free Radic Biol Med ; 24(4): 632-42, 1998 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-9559875

RESUMO

Occupational exposure to crocidolite asbestos is associated with the development of nonmalignant and malignant pulmonary disease. Considerable evidence indicates that the mechanisms of asbestos-induced toxicity involve the production of active oxygen species (AOS). Production of AOS in excess of cellular defenses creates an environment of oxidative stress and stimulates the expression of a number of different genes whose products may be involved in mediating responses from oxidant injury. To further investigate the mechanisms of asbestos-induced pathogenicity, we have examined by Western blot analyses the induction of the stress response proteins GRP78 and HSP72/73 in rat lung epithelial cells (RLE) exposed to crocidolite asbestos. In comparative studies, we also examined GRP78, HSP72/73, and cJun expression in RLE cells exposed to equitoxic concentrations of cadmium chloride (CdCl2) and hydrogen peroxide (H2O2). Our results demonstrate that asbestos and H2O2 do not alter GRP78 or HSP72/73 protein levels in RLE cells, but do increase levels of cJun protein. Increases by asbestos and H2O2 were not accompanied by alterations in cellular glutathione levels in this cell type, but asbestos caused elevations in protein levels of manganese-containing superoxide dismutase (MnSOD), an indirect indicator of oxidant stress. In contrast, exposure of cells to CdCl2 led to no changes in MnSOD protein levels, but increases in GRP78, HSP72/73, and cJun proteins as well as significant increases in oxidized and reduced thiol pools. Results suggest that environmental agents causing oxidative injury to lung epithelium elicit different patterns of stress responses.


Assuntos
Amianto/toxicidade , Cloreto de Cádmio/toxicidade , Proteínas de Choque Térmico HSP70 , Proteínas de Choque Térmico/metabolismo , Peróxido de Hidrogênio/toxicidade , Pulmão/efeitos dos fármacos , Estresse Oxidativo , Animais , Proteínas de Transporte/metabolismo , Chaperona BiP do Retículo Endoplasmático , Células Epiteliais/metabolismo , Glutationa/metabolismo , Proteínas de Choque Térmico HSC70 , Proteínas de Choque Térmico HSP72 , Pulmão/metabolismo , Chaperonas Moleculares/metabolismo , Proteínas Proto-Oncogênicas c-jun/metabolismo , Ratos , Superóxido Dismutase/metabolismo
13.
Free Radic Biol Med ; 24(5): 778-88, 1998 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-9586808

RESUMO

To evaluate the contribution of reactive nitrogen species to inflammation by asbestos, Fischer 344 rats were exposed to crocidolite or chrysotile asbestos by inhalation to determine whether increases occurred in nitric oxide (NO.) metabolites from alveolar macrophages (AMs). AMs from animals inhaling asbestos showed significant elevations (p < .05) in nitrite/nitrate levels which were ameliorated by NG-monomethyl-L-arginine (NMMA), an inhibitor of inducible nitric oxide synthase (iNOS) activity. Temporal patterns of NO. generation from AMs correlated with neutrophil influx in bronchoalveolar lavage samples after asbestos inhalation or bleomycin instillation, another model of pulmonary fibrosis. To determine the molecular mechanisms and specificity of iNOS promoter activation by asbestos, RAW 264.7 cells, a murine macrophage-like line, and AMs isolated from control rats were exposed to crocidolite asbestos in vitro. These cells showed increases in steady-state levels of iNOS mRNA in response to asbestos and more dramatic increases in both iNOS mRNA and immunoreactive protein after addition of lipopolysaccharide (LPS). After transfection of an iNOS promoter/luciferase reporter construct, RAW 264.7 cells exposed to LPS, crocidolite asbestos and its nonfibrous analog, riebeckite, revealed increases in luciferase activity whereas cristobalite silica had no effects. Studies suggest that NO. generation may be important in cell injury and inflammation by asbestos.


Assuntos
Amianto/toxicidade , Macrófagos Alveolares/efeitos dos fármacos , Nitratos/metabolismo , Óxido Nítrico/biossíntese , Nitritos/metabolismo , Administração por Inalação , Animais , Bleomicina/farmacologia , Líquido da Lavagem Broncoalveolar/citologia , Células Cultivadas , Radicais Livres , Imuno-Histoquímica , Macrófagos Alveolares/metabolismo , Masculino , Oxirredução , Fibrose Pulmonar/etiologia , Fibrose Pulmonar/metabolismo , Ratos , Ratos Endogâmicos F344
14.
Antioxid Redox Signal ; 2(3): 379-89, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11229351

RESUMO

Aging is characterized by an accumulation of oxidative injury to DNA, RNA, proteins, lipids, and carbohydrates. In addition to damage, oxidative stress can initiate cell signaling cascades that modulate cell function, growth, and death. Aging and two common age-related diseases, diabetes mellitus and atherosclerosis, may share common oxidant-related signaling pathways that lead to abnormal transcription factor activation and ultimately to cellular dysfunction, degeneration, or death. This review will focus on approaches to evaluate key redox-sensitive signaling pathways and the transcription factors altered by diabetes, atherosclerosis, and aging.


Assuntos
Envelhecimento , Transdução de Sinais , Fatores de Transcrição/metabolismo , Arteriosclerose/metabolismo , Diabetes Mellitus/metabolismo , Humanos , Modelos Biológicos , Estresse Oxidativo , Oxigênio/metabolismo
15.
Environ Health Perspect ; 106 Suppl 5: 1191-5, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9788897

RESUMO

Oxidants are important in the regulation of signal transduction and gene expression. Multiple classes of genes are transcriptionally activated by oxidants and are implicated in different phenotypic responses. In the present study, we performed differential mRNA display to elucidate genes that are induced or repressed after exposure of rat lung epithelial (RLE) cells to H2O2 or crocidolite asbestos, a pathogenic mineral that generates oxidants. After 8 or 24 hr of exposure, RNA was extracted, reverse transcribed, and amplified by polymerase chain reaction with degenerate primers to visualize alterations in gene expression. The seven clones obtained were sequenced and encoded the mitochondrial genes, NADH dehydrogenase subunits ND5 and ND6, and 16S ribosomal RNA. Evaluation of their expression by Northern blot analysis revealed increased expression of 16S rRNA after 1 or 2 hr of exposure to H2O2. At later time periods (4 and 24 hr), mRNA levels of 16S rRNA and NADH dehydrogenase were decreased in H2O2-treated RLE cells when compared to sham controls. Crocidolite asbestos caused increases in 16S rRNA levels after 8 hr of exposure, whereas after 24 hr of exposure to asbestos, 16S rRNA levels were decreased in comparison to sham controls. In addition to these oxidants, the nitric oxide generator spermine NONOate caused similar decreases in NADH dehydrogenase mRNA levels after 4 hr of exposure. The present data and previous studies demonstrated that all oxidants examined resulted in apoptosis in RLE cells during the time frame where alterations of mitochondrial gene expression were observed. As the mitochondrion is a major organelle that controls apoptosis, alterations in expression of mitochondrial genes may be involved in the regulation of apoptosis.


Assuntos
Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Mitocôndrias/genética , Oxidantes/toxicidade , Animais , Apoptose , Asbesto Crocidolita/toxicidade , Linhagem Celular , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Expressão Gênica/efeitos dos fármacos , Peróxido de Hidrogênio/toxicidade , Pulmão/citologia , NADH Desidrogenase/genética , Alvéolos Pulmonares/citologia , Alvéolos Pulmonares/efeitos dos fármacos , Alvéolos Pulmonares/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Ribossômico 16S/genética , Ratos
16.
Environ Health Perspect ; 105 Suppl 5: 1121-5, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9400710

RESUMO

In recent years, it has become apparent that minerals can trigger alterations in gene expression by initiating signaling events upstream of gene transactivation. These cascades may be initiated at the cell surface after interaction of minerals with the plasma membrane either through receptorlike mechanisms or integrins. Alternatively, signaling pathways may be stimulated by active oxygen species generated both during phagocytosis of minerals and by redox reactions on the mineral surface. At least two signaling cascades linked to activation of transcription factors, i.e., DNA-binding proteins involved in modulating gene expression and DNA replication, are stimulated after exposure of lung cells to asbestos fibers in vitro. These include nuclear factor kappa B (NF kappa B) and the mitogen-activated protein kinase (MAPK) cascade important in regulation of the transcription factor, activator protein-1 (AP-1). Both NF kappa B and AP-1 bind to specific DNA sequences within the regulatory or promoter regions of genes that are critical to cell proliferation and inflammation. Unraveling the cell signaling cascades initiated by mineral dusts and pharmacologic inhibition of these events may be important for the control and treatment of mineral-associated occupational diseases.


Assuntos
Amianto/toxicidade , Carcinógenos/toxicidade , Comunicação Celular/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Animais , Asbesto Crocidolita/toxicidade , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Cricetinae , Eletroforese em Gel de Poliacrilamida , Células Epiteliais/efeitos dos fármacos , Receptores ErbB/genética , NF-kappa B/efeitos dos fármacos , Fenótipo , Fator de Transcrição AP-1/biossíntese , Fator de Transcrição AP-1/genética
19.
J Bacteriol ; 158(3): 1204-7, 1984 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-6427192

RESUMO

Expression of the Escherichia coli lactose operon in Rhizobium meliloti 104A14 made the cells sensitive to the addition of the beta-galactosides lactose, phenyl-beta-D-galactoside, and lactobionic acid. Growth stopped when the beta-galactoside was added and viability decreased modestly during the next few hours, but little cell lysis was observed and the cells appeared normal. Protein synthesis was not inhibited. Growth was inhibited only when beta-galactosidase expression was greater than 160 U. Lactose-resistant mutants had defects in the plasmid-carried E. coli beta-galactosidase or beta-galactoside permease and in the R. meliloti genome. We speculate that uncontrolled production of galactose by the action of the lactose operon proteins was responsible for growth inhibition.


Assuntos
Escherichia coli/genética , Óperon Lac/efeitos dos fármacos , Lactose/toxicidade , Rhizobium/crescimento & desenvolvimento , Cinética , Rhizobium/efeitos dos fármacos , Rhizobium/genética , beta-Galactosidase/genética
20.
J Bacteriol ; 158(3): 1070-7, 1984 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-6327625

RESUMO

A set of plasmid cloning vehicles was developed to facilitate the construction of gene or operon fusions in Rhizobium meliloti. The vehicles also contain a broad-host-range replicon and could be introduced into bacteria either by transformation or by transduction, using bacteriophage P2. Insertion of foreign DNA into a unique restriction endonuclease cleavage site promotes the synthesis of either the Escherichia coli lactose operon or the kanamycin phosphotransferase gene from transposon Tn5. Expression of the lactose operon could be detected by observing the color of Rhizobium colonies on medium that contained a chromogenic indicator. We also determined the growth conditions that make it possible to select either for or against the expression of the E. coli lactose operon in R. meliloti. Recombinant plasmids were constructed by inserting MboI restriction fragments of R. meliloti DNA into one of the vehicles, pMK353 . Expression of beta-galactosidase by a number of these recombinants was measured in both R. meliloti and E. coli.


Assuntos
Clonagem Molecular , Galactosidases/genética , Genes Bacterianos , Genes , Rhizobium/genética , beta-Galactosidase/genética , Bacteriófagos/genética , Sequência de Bases , Enzimas de Restrição do DNA , DNA Bacteriano/isolamento & purificação , DNA Recombinante/metabolismo , Escherichia coli/enzimologia , Escherichia coli/genética , Plasmídeos , Rhizobium/enzimologia , Especificidade da Espécie
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa