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1.
Respir Med ; 183: 106419, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33957436

RESUMO

BACKGROUND: Cognitive dysfunction is often reported in patients who have experienced acute respiratory distress syndrome (ARDS). Extra Corporeal Membrane Oxygenation (ECMO) therapy is increasingly used to manage ARDS patients in ICU, transforming survival rates. However, few studies have examined cognitive outcomes. METHODS: We examined self-reported cognitive complaints, psychiatric outcomes and neuropsychological test performance in survivors of severe hypoxaemia managed with VV-ECMO, at 18-24 month follow-up, compared with a group of healthy controls. RESULTS: Over 70% of ECMO-treated patients (N = 46) complained of difficulty in at least one aspect of cognition on self-report measures (study 1). However, a much lower frequency of cognitive impairment was found on formal neuropsychological testing (study 2). Mean neuropsychological test scores of the ECMO group (N = 24) did not significantly differ from healthy controls (N = 23) after controlling for depression. Less than 30% of ECMO-treated patients showed impairments in anterograde memory, and deficits on general IQ or executive function were seen in <17% of patients. However, we observed high levels of self-reported anxiety and depression in the ECMO-treated patients. CONCLUSIONS: Cognitive outcomes in ECMO-treated patients were generally good, with preserved neuropsychological function in the majority of patients, despite severe hypoxaemia and high rates of self-reported difficulties. However, we saw high levels of mental health symptoms in these patients, highlighting a need for psychological support.


Assuntos
Cognição , Oxigenação por Membrana Extracorpórea , Síndrome do Desconforto Respiratório/psicologia , Síndrome do Desconforto Respiratório/terapia , Adulto , Idoso , Ansiedade , Depressão , Função Executiva , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Medidas de Resultados Relatados pelo Paciente , Fatores de Tempo , Adulto Jovem
2.
J Intensive Care Soc ; 21(1): 28-32, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32284715

RESUMO

The diagnosis of death using neurological criteria is an important legal method of establishing death in the UK. The safety of the diagnosis lies in the exclusion of conditions which may mask the diagnosis and the testing of the fundamental reflexes of the brainstem including the apnoea reflex. Extracorporeal membrane oxygenation for cardiac or respiratory support can impact upon these tests, both through drug sequestration in the circuit and also through the ability to undertake the apnoea test. Until recently, there has been no nationally accepted guidance regarding the conduct of the tests to undertake the diagnosis of death using neurological criteria for a patient on extracorporeal membrane oxygenation. This article considers both the background to and the process of guideline development.

3.
Aliment Pharmacol Ther ; 37(10): 989-97, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23577724

RESUMO

BACKGROUND: The timely diagnosis of acute kidney injury (AKI) in liver cirrhosis is challenging. AIM: To evaluate whether quantification of glomerular filtration rate (GFR), proteinuria and kidney injury biomarkers can accurately predict the development of AKI. METHODS: A prospective cohort analysis of patients with cirrhosis was performed. Measures of baseline kidney function included serum creatinine, iohexol clearance and urine protein:creatinine ratio. Blood and urine samples were collected daily. A retrospective analysis of cystatin C GFR and neutrophil gelatinase-associated lipocalin (NGAL) measured 48 h prior to the diagnosis of AKI was undertaken to evaluate their ability to predict the development of AKI. RESULTS: Eighteen of the 34 cirrhosis patients studied developed AKI. A GFR <60 mL/min/1.73 m(2) was identified in 56% with Iohexol clearance compared to 8% using the four-variable modified diet in renal disease formula (P < 0.0001). Prediction of AKI, 48 h prior to the development of AKI with cystatin C GFR and serum NGAL concentration were similar; area under the receiver operating curve (AUROC) values 0.74 (0.51-0.97), P = 0.04 and 0.72 (0.52-0.92), P = 0.02 respectively. The development of AKI was strongly predicted by urine protein:creatinine ratio above the cut-off of >30 (equivalent to 300 mg/day of proteinuria) sensitivity 82% (57-96) and specificity 80% (52-96), AUROC 0.86 (0.73-0.98), P ≤ 0.0001. [OR 21 (3-133), P ≤ 0.002]. CONCLUSIONS: In patients with liver cirrhosis a urine protein:creatinine ratio >30 predicts AKI. Iohexol clearance and cystatin C formulae identify a greater proportion of patients with a GFR <60 mL/min/1.73 m(2), which also predicts the development of AKI.


Assuntos
Injúria Renal Aguda/diagnóstico , Taxa de Filtração Glomerular , Cirrose Hepática/complicações , Proteinúria/diagnóstico , Injúria Renal Aguda/etiologia , Proteínas de Fase Aguda/urina , Adulto , Idoso , Biomarcadores/sangue , Biomarcadores/urina , Estudos de Coortes , Meios de Contraste/farmacocinética , Creatinina/sangue , Creatinina/urina , Feminino , Humanos , Iohexol/farmacocinética , Testes de Função Renal , Lipocalina-2 , Lipocalinas/sangue , Lipocalinas/urina , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Proteínas Proto-Oncogênicas/sangue , Proteínas Proto-Oncogênicas/urina
4.
BJOG ; 117(1): 62-8, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20002370

RESUMO

OBJECTIVE: The aim of this study was to evaluate the outcome of laparoscopic hysteropexy, a surgical technique for the management of uterine prolapse, involving suspension of the uterus from the sacral promontory using bifurcated polypropylene mesh. DESIGN: The investigation was designed as a prospective observational study (clinical audit). SETTING: The study was undertaken at a tertiary referral urogynaecology unit in the UK. POPULATION: The participants comprised 51 consecutive women with uterovaginal prolapse, who chose laparoscopic hysteropexy as one of the available surgical options. METHODS: The hysteropexy was conducted laparoscopically in all cases. A bifurcated polypropylene mesh was used to suspend the uterus from the sacral promontory. The two arms of the mesh were introduced through bilateral windows created in the broad ligaments, and were sutured to the anterior cervix; the mesh was then fixed to the anterior longitudinal ligament over the sacral promontory, to elevate the uterus. MAIN OUTCOME MEASURES: Cure of the uterine prolapse was evaluated subjectively using the International Consultation on Incontinence Questionnaire for vaginal symptoms (ICIQ-VS), and objectively by vaginal examination using the Baden-Walker halfway system and the pelvic organ prolapse quantification (POP-Q) scale. Operative and postoperative complications were also assessed. RESULTS: The mean age of the 51 women was 52.5 years (range 19-71 years). All were sexually active, and at least three of them expressed a strong desire to have children in the future. All were available for follow-up in clinic at 10 weeks, and 38 have completed the questionnaires. In 50 out of 51 women the procedure was successful, with no objective evidence of uterine prolapse on examination at follow-up; there was one failure. Significant subjective improvements in prolapse symptoms, sexual wellbeing and related quality of life were observed, as detected by substantial reductions in the respective questionnaire scores. CONCLUSIONS: Laparoscopic hysteropexy is both a feasible and an effective procedure for correcting uterine prolapse without recourse to hysterectomy. It allows restoration of the length of the vagina without compromising its calibre, and is therefore likely to have a favourable functional outcome.


Assuntos
Histeroscopia/métodos , Laparoscopia/métodos , Prolapso Uterino/cirurgia , Adulto , Idoso , Estudos de Viabilidade , Feminino , Humanos , Auditoria Médica , Pessoa de Meia-Idade , Polipropilenos/uso terapêutico , Estudos Prospectivos , Telas Cirúrgicas , Resultado do Tratamento
5.
Int J Syst Evol Microbiol ; 58(Pt 10): 2249-52, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18842835

RESUMO

This paper reports on a Leptospira isolate of bovine origin and its identification as belonging to a previously unknown serovar, for which the name Topaz is proposed. The isolate (94-79970/3) was cultured from bovine urine from a north Queensland dairy farm in Australia. Strain 94-79970/3 grew at 30 degrees C in Ellinghausen McCullough Johnson Harris (EMJH) medium but failed to grow at 13 degrees C in EMJH medium or in the presence of 8-azaguanine. Serologically, strain 94-79970/3 produced titres against the Leptospira borgpetersenii serovar Tarassovi, the reference strain for the Tarassovi serogroup; however, no significant titres to any other serovars within the serogroup were obtained. Using 16S rRNA and DNA gyrase subunit B gene analysis, strain 94-79970/3 was identified as a member of the species Leptospira weilii. We propose that the serovar be named Topaz, after the location where the original isolate was obtained. The reference strain for this serovar is 94-79970/3 (=KIT 94-79970/3=LT722).


Assuntos
Bovinos/microbiologia , Leptospira/classificação , Leptospira/genética , Animais , DNA Girase/genética , DNA Bacteriano/genética , Genes Bacterianos , Genes de RNAr , Leptospira/isolamento & purificação , Leptospirose/microbiologia , Leptospirose/urina , Leptospirose/veterinária , Dados de Sequência Molecular , Fenótipo , Queensland , RNA Ribossômico 16S/genética , Sorotipagem
6.
J Obstet Gynaecol ; 28(4): 410-2, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18604676

RESUMO

Our objective was to assess the benefit of additional pelvic floor exercises, supervised by specialist physiotherapists, in the secondary care management of urinary stress incontinence. This is a retrospective cohort study in a UK University teaching hospital. A total of 317 women were referred from primary care to a specialist continence clinic for management of urinary stress incontinence. The cases were identified from the clinic database and a case note review performed. Data were collected on initial clinical assessment, suitability for pelvic floor exercises and outcome of treatment. The main outcome measures were adherence to primary care guidelines, suitability for further pelvic floor exercises and outcome of exercises. In total, 201 women were deemed suitable for a trial of further pelvic floor exercises, of whom 82 had previously attempted this in the primary care setting. After completing a course of physiotherapist supervised exercises, 105 women were able to be discharged from secondary care as a result of their symptoms improving. Of these women, 46 had previously attempted pelvic floor exercises in the community. It was seen that the primary care guidelines are poorly adhered to and where pelvic floor exercises are attempted in the community, the outcomes appear to be suboptimal. In appropriately selected women, a trial of additional physiotherapist-supervised exercises is beneficial and can reduce the urodynamic and surgical workload by 33%.


Assuntos
Terapia por Exercício , Incontinência Urinária por Estresse/reabilitação , Adulto , Idoso , Feminino , Humanos , Pessoa de Meia-Idade , Educação de Pacientes como Assunto , Modalidades de Fisioterapia
7.
Oncogene ; 27(39): 5204-13, 2008 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-18504438

RESUMO

Loss of 1p36 heterozygosity commonly occurs with MYCN amplification in neuroblastoma tumors, and both are associated with an aggressive phenotype. Database searches identified five microRNAs that map to the commonly deleted region of 1p36 and we hypothesized that the loss of one or more of these microRNAs contributes to the malignant phenotype of MYCN-amplified tumors. By bioinformatic analysis, we identified that three out of the five microRNAs target MYCN and of these miR-34a caused the most significant suppression of cell growth through increased apoptosis and decreased DNA synthesis in neuroblastoma cell lines with MYCN amplification. Quantitative RT-PCR showed that neuroblastoma tumors with 1p36 loss expressed lower level of miR-34a than those with normal copies of 1p36. Furthermore, we demonstrated that MYCN is a direct target of miR-34a. Finally, using a series of mRNA expression profiling experiments, we identified other potential direct targets of miR-34a, and pathway analysis demonstrated that miR-34a suppresses cell-cycle genes and induces several neural-related genes. This study demonstrates one important regulatory role of miR-34a in cell growth and MYCN suppression in neuroblastoma.


Assuntos
MicroRNAs/genética , Proteínas Nucleares/genética , Proteínas Oncogênicas/genética , Sequência de Bases , Deleção Cromossômica , Cromossomos Humanos Par 1 , Primers do DNA , Humanos , Perda de Heterozigosidade , Mutagênese Sítio-Dirigida , Proteína Proto-Oncogênica N-Myc , Neuroblastoma/genética , Neuroblastoma/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa
8.
BJOG ; 114(10): 1278-82, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17877680

RESUMO

OBJECTIVES: To report the short- and medium-term complications of laparoscopic laser excisional surgery for rectovaginal endometriosis. DESIGN: Retrospective cohort study. SETTING: University teaching hospital, UK. POPULATION: A total of 128 women with histologically confirmed rectovaginal endometriosis who underwent laparoscopic laser surgery between May 1999 and September 2006. METHODS: Women were identified from operative database, and a case note review was performed. Data for surgical outcome and surgical complications were collected. MAIN OUTCOME MEASURES: Rates of urinary tract and colorectal complications. RESULTS: A total of 128 women underwent surgery. Of these, 32 required intraoperative closure of a rectal wall defect, including 3 segmental rectosigmoid resections. There were three rectovaginal fistulae and one ureterovaginal fistula. Ureteric damage occurred in two women, and five women suffered postoperative urinary retention. The risk of intraoperative bowel intervention was increased in women who complained of cyclical rectal bleeding. CONCLUSION: Laparoscopic laser excision of rectovaginal endometriosis is a safe procedure with similar, if not lower, complication rates to other published surgical series.


Assuntos
Endometriose/cirurgia , Laparoscopia/efeitos adversos , Terapia a Laser/efeitos adversos , Doenças Retais/cirurgia , Doenças Vaginais/cirurgia , Adulto , Estudos de Coortes , Doenças do Colo/etiologia , Feminino , Hemorragia Gastrointestinal/etiologia , Humanos , Tempo de Internação , Pessoa de Meia-Idade , Prognóstico , Fístula Retovaginal/etiologia , Estudos Retrospectivos , Doenças Ureterais/etiologia , Fístula Urinária/etiologia , Fístula Vaginal/etiologia
9.
Epidemiol Infect ; 134(6): 1217-25, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16690001

RESUMO

Leptospirosis is one of the most commonly encountered zoonoses in both Australia and the rest of the world. The incidence of leptospirosis in Queensland over the 7-year study period (1998-2004) was 3.1/100000 population. Enhanced surveillance questionnaires were used to collect patient data and facilitate an epidemiological investigation of leptospirosis in Queensland. Farming occupations comprised the majority of occupational exposure cases, however, recreational exposure accounted for 18% of the 883 cases. Rainfall and the presence of animal hosts had the most influence on the incidence of leptospirosis. Several trends in serovar numbers over this period are noted, in particular the emergence of L. borgpetersenii serovar Arborea, which accounted for 22% of all leptospirosis cases in Australia and 68% of South-East Queensland cases in 2004. Assessment of epidemiological trends in leptospirosis is important to obtain directed public health intervention and outcomes in the reduction of leptospirosis cases.


Assuntos
Leptospira/imunologia , Leptospira/isolamento & purificação , Leptospirose/epidemiologia , Austrália/epidemiologia , Humanos , Leptospira/genética , Leptospirose/microbiologia , Exposição Ocupacional , Queensland/epidemiologia , Estações do Ano , Testes Sorológicos , Sorotipagem
10.
J Arthroplasty ; 20(8): 990-7, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16376253

RESUMO

This prospective cohort study of 153 patients aimed to determine the economic and health costs of waiting for total hip arthroplasty (THA). Health-related quality of life, using self-completed WOMAC and EQ-5D questionnaires, was assessed monthly from enrolment preoperatively to 6 months postsurgery. Monthly cost diaries were used to record costs. The mean waiting time was 5.1 months and mean total cost of waiting for surgery was NZ 4305 dollars(US 2876 dollars) per person (pp) (NZ 1 dollar = US 0.668 dollar). Waiting more than 6 months was associated with a higher total mean cost (NZ 4278 dollars/US 2858 dollars pp) than waiting less than 6 months (NZ 2828 dollars/US 1889 dollars pp; P < .01). Improvements from preoperative to postoperative WOMAC and EQ-5D scores were identified (P < or = .01). Waiting longer led to poorer physical function preoperatively (P < or = .01). Those with poor initial health status showed greater improvement in WOMAC (P = .0001) and EQ-5D (P = .003) measures by 6 months after surgery. Longer waits for total hip arthroplasty incur greater economic costs and deterioration in physical function while waiting.


Assuntos
Artroplastia de Quadril/economia , Osteoartrite do Quadril/cirurgia , Avaliação de Resultados em Cuidados de Saúde , Listas de Espera , Adulto , Idoso , Idoso de 80 Anos ou mais , Custos e Análise de Custo , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Qualidade de Vida , Estatísticas não Paramétricas , Inquéritos e Questionários
12.
Gene ; 268(1-2): 87-96, 2001 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-11368904

RESUMO

Rb, c-Jun and dnmt1 play critical roles in the process of cellular differentiation. We demonstrate that a regulatory region of murine dnmt1 contains an element which is responsible for transactivation by Rb and c-Jun in P19 embryocarcinoma cells which is not observed in Y1 adrenocarcinoma cells. During differentiation of P19 cells, the induction of Rb and c-Jun coincides with an increase of dnmt1 mRNA. Using linker scanning mutagenesis we identify the element that is responsible for this activation to be a non-canonical AP-1 site. Our data is an example of how a proto-oncogene activates its downstream effectors by recruiting a tumor suppressor. This interaction of Rb and a proto-oncogene might play an important role in differentiation. The responsiveness of dnmt1 to this type of signal is consistent with an important role for regulated expression of dnmt1 during cellular differentiation.


Assuntos
DNA (Citosina-5-)-Metiltransferases/genética , Proteínas Proto-Oncogênicas c-jun/metabolismo , Sequências Reguladoras de Ácido Nucleico , Proteína do Retinoblastoma/metabolismo , Animais , Sequência de Bases , Sítios de Ligação , Ligação Competitiva , Carcinoma Embrionário/genética , Carcinoma Embrionário/patologia , Diferenciação Celular/genética , Extratos Celulares , DNA (Citosina-5-)-Metiltransferase 1 , DNA (Citosina-5-)-Metiltransferases/metabolismo , Camundongos , Dados de Sequência Molecular , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-jun/genética , Proteína do Retinoblastoma/genética , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo , Ativação Transcricional , Células Tumorais Cultivadas
13.
J Biol Chem ; 276(10): 6930-6, 2001 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-11104769

RESUMO

DNA-cytosine-5-methyltransferase 1 (DNMT1) is the enzyme believed to be responsible for maintaining the epigenetic information encoded by DNA methylation patterns. The target recognition domain of DNMT1, the domain responsible for recognizing hemimethylated CGs, is unknown. However, based on homology with bacterial cytosine DNA methyltransferases it has been postulated that the entire catalytic domain, including the target recognition domain, is localized to 500 amino acids at the C terminus of the protein. The N-terminal domain has been postulated to have a regulatory role, and it has been suggested that the mammalian DNMT1 is a fusion of a prokaryotic methyltransferase and a mammalian DNA-binding protein. Using a combination of in vitro translation of different DNMT1 deletion mutant peptides and a solid-state hemimethylated substrate, we show that the target recognition domain of DNMT1 resides in the N terminus (amino acids 122-417) in proximity to the proliferating cell nuclear antigen binding site. Hemimethylated CGs were not recognized specifically by the postulated catalytic domain. We have previously shown that the hemimethylated substrates utilized here act as DNMT1 antagonists and inhibit DNA replication. Our results now indicate that the DNMT1-PCNA interaction can be disrupted by substrate binding to the DNMT1 N terminus. These results point toward new directions in our understanding of the structure-function of DNMT1.


Assuntos
DNA (Citosina-5-)-Metiltransferases/química , Sequência de Bases , Sítios de Ligação , Western Blotting , Domínio Catalítico , DNA (Citosina-5-)-Metiltransferase 1 , Deleção de Genes , Humanos , Metilação , Dados de Sequência Molecular , Oligonucleotídeos/metabolismo , Peptídeos/química , Testes de Precipitina , Antígeno Nuclear de Célula em Proliferação/química , Ligação Proteica , Biossíntese de Proteínas , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Relação Estrutura-Atividade , Transcrição Gênica
14.
Ann N Y Acad Sci ; 910: 156-74; discussion 175-7, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10911912

RESUMO

Global hypomethylation of genes and repetitive sequences, as well as hypermethylation of certain genes known to be involved in tumor suppression, are observed concurrently in cancer cells. Aberrant expression of DNA methyltransferase 1 (dnmt1) is a downstream effector of multiple tumorigenic pathways, and several data suggest that dnmt1 plays a causal role in these pathways. These data raise two critical questions: Why does ectopic expression of dnmt1 transform cells? and How can global hypomethylation exist in a cell that bears high levels of DNMT1 activity? It is proposed that DNMT1 induces cellular transformation by a mechanism that does not involve DNA methylation and that the low level of methylation in cancer cells is a result of induction of a DNA demethylase in these cells. Both DNMT1 and the demethylase play a causal role in cellular transformation and are candidate anticancer targets.


Assuntos
Transformação Celular Neoplásica , Metiltransferases , Transformação Celular Neoplásica/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Metiltransferases/genética , Neoplasias/genética , Oligonucleotídeos Antissenso , Células Tumorais Cultivadas
15.
J Biol Chem ; 275(24): 17986-90, 2000 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-10849434

RESUMO

Ectopic expression of DNA methyltransferase transforms vertebrate cells, and inhibition of DNA methyltransferase reverses the transformed phenotype by an unknown mechanism. We tested the hypothesis that the presence of an active DNA methyltransferase is required for DNA replication in human non-small cell lung carcinoma A549 cells. We show that the inhibition of DNA methyltransferase by two novel mechanisms negatively affects DNA synthesis and progression through the cell cycle. Competitive polymerase chain reaction of newly synthesized DNA shows decreased origin activity at three previously characterized origins of replication following DNA methyltransferase inhibition. We suggest that the requirement of an active DNA methyltransferase for the functioning of the replication machinery has evolved to coordinate DNA replication and inheritance of the DNA methylation pattern.


Assuntos
DNA (Citosina-5-)-Metiltransferases/antagonistas & inibidores , Replicação do DNA , Animais , Divisão Celular , Linhagem Celular , DNA (Citosina-5-)-Metiltransferase 1 , DNA (Citosina-5-)-Metiltransferases/genética , Inibidores Enzimáticos/farmacologia , Humanos , Oligodesoxirribonucleotídeos Antissenso/farmacologia , Reação em Cadeia da Polimerase
16.
Endocr Res ; 26(4): 921-30, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11196471

RESUMO

We utilized Y1 adrenocortical carcinoma cell line as a model system to dissect the events regulating epigenomic gene silencing in tumor cells. We show here that the chromatin structure of c21 gene is inactive in Y1 cells and that it could be reconfigured to an active form by either expressing antisense mRNA to DNA methyltransferase 1 (dnmt1) or an attenuator of Ras protooncogenic signaling hGAP. Surprisingly however, the known inducer of active chromatin structure the histone deacetylase inhibitor trichostatin A TSA fails to induce expression of c21. These results suggest that the primary cause of c21 gene silencing is independent of histone deacetylation. We present a model to explain the possible roles of the different components of the epigenome and the DNA methylation and demethylation machineries in silencing c21 gene expression.


Assuntos
Neoplasias do Córtex Suprarrenal/genética , Inativação Gênica , Esteroide 21-Hidroxilase/genética , Neoplasias do Córtex Suprarrenal/patologia , Animais , Cromatina/química , Cromatina/fisiologia , DNA (Citosina-5-)-Metiltransferase 1 , DNA (Citosina-5-)-Metiltransferases/fisiologia , Camundongos , Transdução de Sinais/fisiologia , Células Tumorais Cultivadas , Proteínas ras/fisiologia
17.
Eur J Biochem ; 264(1): 191-9, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10447688

RESUMO

This paper tests the hypothesis that expression of the DNA methyltransferase, dnmt1, gene is regulated by a methylation-sensitive DNA element. Methylation of DNA is an attractive system for feedback regulation of DNA methyltransferase as the final product of the reaction, methylated DNA, can regulate gene expression in cis. We show that an AP-1-dependent regulatory element of dnmt1 is heavily methylated in most somatic tissues and in the mouse embryonal cell line, P19, and completely unmethylated in a mouse adrenal carcinoma cell line, Y1. dnmt1 is highly over expressed in Y1 relative to P19 cell lines. Global inhibition of DNA methylation in P19 cells by 5-azadeoxycytidine results in demethylation of the AP-1 regulatory region and induction of dnmt1 expression in P19cells, but not Y1 cells. We propose that this regulatory region of dnmt1 acts as a sensor of the DNA methylation capacity of the cell. These results provide an explanation for the documented coexistence of global hypomethylation and high levels of DNA methyltransferase activity in many cancer cells and for the carcinogenic effect of hypomethylating diets.


Assuntos
DNA-Citosina Metilases/genética , Regulação Enzimológica da Expressão Gênica , Animais , Sequência de Bases , Linhagem Celular , Metilação de DNA , Primers do DNA , Retroalimentação , Camundongos , Regiões Promotoras Genéticas , Sequências Reguladoras de Ácido Nucleico
18.
J Biol Chem ; 274(15): 10105-12, 1999 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-10187792

RESUMO

This paper tests the hypothesis that DNA methyltransferase plays a causal role in cellular transformation induced by SV40 T antigen. We show that T antigen expression results in elevation of DNA methyltransferase (MeTase) mRNA, DNA MeTase protein levels, and global genomic DNA methylation. A T antigen mutant that has lost the ability to bind pRb does not induce DNA MeTase. This up-regulation of DNA MeTase by T antigen occurs mainly at the posttranscriptional level by altering mRNA stability. Inhibition of DNA MeTase by antisense oligonucleotide inhibitors results in inhibition of induction of cellular transformation by T antigen as determined by a transient transfection and soft agar assay. These results suggest that elevation of DNA MeTase is an essential component of the oncogenic program induced by T antigen.


Assuntos
Antígenos Virais de Tumores/metabolismo , Transformação Celular Viral , Metilases de Modificação do DNA/metabolismo , Células 3T3 , Animais , Antígenos Virais de Tumores/genética , Metilação de DNA , Metilases de Modificação do DNA/biossíntese , Indução Enzimática , Camundongos , Camundongos Endogâmicos BALB C , Oligonucleotídeos Antissenso/metabolismo , Processamento de Proteína Pós-Traducional , RNA Mensageiro/metabolismo , Vírus 40 dos Símios , Transfecção , Regulação para Cima
19.
Ultrasound Obstet Gynecol ; 10(4): 261-4, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9383877

RESUMO

We evaluated the effectiveness of 10-14 week nuchal translucency measurement in routine ultrasound screening for Down's syndrome, and its effect on the sensitivity of subsequent maternal serum biochemistry. This was an observational study, in which all women attending for antenatal care at a district general hospital were routinely offered a first-trimester nuchal translucency scan and second-trimester quadruple maternal serum biochemistry as screening tests for Down's syndrome. The main outcome measures were abnormal fetal karyotype and the performance of screening tests. A total of 3604 women were scanned in the first trimester of pregnancy. Excluding the cases that did not fit the entry criteria (n = 344, 9.6%) and in which nuchal translucency measurements were not possible (n = 340, 9.4%), a total of 2920 women were screened. A nuchal translucency-derived risk of 1:200 for an aneuploid pregnancy resulted in a 5% (n = 147) screen-positive rate. Screening using this risk enabled the first-trimester detection of five of seven (71%) fetuses with trisomy 21 and 14 of 18 (78%) aneuploid fetuses. Second-trimester maternal serum biochemistry testing was performed in 1904 of the women who had nuchal translucency screening, with a screen-positive rate of 7.5% (n = 143). Only one extra case of Down's syndrome would have been detected by maternal serum biochemistry testing if nuchal translucency screening had been implemented at a risk level of 1:300. This study demonstrates that first-trimester nuchal translucency measurement is effective in routine screening for fetal chromosomal abnormality. Furthermore, the implementation of a nuchal translucency screening program will significantly reduce the positive predictive value of second-trimester maternal serum biochemistry testing.


Assuntos
Síndrome de Down/prevenção & controle , Ultrassonografia Pré-Natal , Adulto , Biomarcadores/sangue , Síndrome de Down/diagnóstico , Síndrome de Down/diagnóstico por imagem , Síndrome de Down/epidemiologia , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Cariotipagem , Idade Materna , Pescoço/diagnóstico por imagem , Valor Preditivo dos Testes , Gravidez , Gravidez de Alto Risco , Fatores de Risco , Sensibilidade e Especificidade
20.
Genomics ; 38(3): 331-9, 1996 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-8975710

RESUMO

The presence of an extra copy of human chromosome 21 (trisomy 21), especially region 21q22.2, causes many phenotypes in Down syndrome, including mental retardation. To study genes potentially responsible for some of these phenotypes, we cloned a human candidate gene (DYRK) from 21q22.2 and its murine counterpart (Dyrk) that are homologous to the Drosophila minibrain (mnb) gene required for neurogenesis and to the rat Dyrk gene (dual specificity tyrosine phosphorylation regulated kinase). The three mammalian genes are highly conserved, >99% identical at the protein level over their 763-amino-acid (aa) open reading frame; in addition, the mammalian genes are 83% identical over 414 aa to the smaller 542-aa mnb protein. The predicted human DYRK and murine Dyrk proteins both contain a nuclear targeting signal sequence, a protein kinase domain, a putative leucine zipper motif, and a highly conserved 13-consecutive-histidine repeat. Fluorescence in situ hybridization and regional mapping data localize DYRK between markers D21S336 and D21S337 in the 21q22.2 region. Northern blot analysis indicated that both human and murine genes encode approximately 6-kb transcripts. PCR screening of cDNA libraries derived from various human and murine tissues indicated that DYRK and Dyrk are expressed both during development and in the adult. In situ hybridization of Dyrk to mouse embryos (13, 15, and 17 days postcoitus) indicates a differential spatial and temporal pattern of expression, with the most abundant signal localized in brain gray matter, spinal cord, and retina. The observed expression pattern is coincident with many of the clinical findings in trisomy 21. Its chromosomal locus (21q22. 2), its homology to the mnb gene, and the in situ hybridization expression patterns of the murine Dyrk combined with the fact that transgenic mice for a YAC to which DYRK maps are mentally deficient suggest that DYRK may be involved in the abnormal neurogenesis found in Down syndrome.


Assuntos
Cromossomos Humanos Par 21/genética , Genes , Camundongos/genética , Proteínas do Tecido Nervoso/genética , Proteínas Quinases/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Tirosina Quinases , Adulto , Sequência de Aminoácidos , Animais , Encéfalo/embriologia , Encéfalo/metabolismo , Mapeamento Cromossômico , Cromossomos Artificiais de Levedura/genética , Síndrome de Down/genética , Proteínas do Olho/biossíntese , Proteínas do Olho/genética , Regulação da Expressão Gênica , Idade Gestacional , Humanos , Hibridização in Situ Fluorescente , Deficiência Intelectual/genética , Camundongos Transgênicos , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/biossíntese , Fenótipo , Ratos , Retina/embriologia , Retina/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Especificidade da Espécie , Medula Espinal/embriologia , Medula Espinal/metabolismo , Quinases Dyrk
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