Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 37
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Prog Urol ; 31(4): 215-222, 2021 Mar.
Artigo em Francês | MEDLINE | ID: mdl-33339737

RESUMO

INTRODUCTION: The main purpose was to assess the failure free survival of adjustable continence therapy ACT®/proACT® after continence was obtained and to seek factors influencing it. MATERIAL AND METHODS: Retrospective, single-center survival study of peri-urethral balloons implanted between 2007 and 2014. Efficacy was defined by the wearing of 0 or 1 safety pad per day. The primary end point was time to failure estimated from a survival curve (Kaplan-Meier). Factors that could influence failure free survival were: sex, age, radiotherapy, diabetes, number of pad before surgery, number of balloon inflation, early complications, mixed urinary incontinence and previous ACT®/proACT® placement. They were analyzed in a COX regression. RESULTS: Of the 82 peri-urethral balloons placed, 41 were effective in 36 patients. The failure free survival was 50 % at 60 months. Radiotherapy, diabetes and previous peri-urethral balloon placement appeared to significantly decrease survival (P=0.031;P=0.025;P=0.029, respectively). Fifteen peri-urethral balloons were still effective at the last follow-up, one was lost to follow-up and 25 required re-intervention for loss of efficacy. The main cause of efficacy loss was system leakage. Fifty-two percent of peri-urethral balloons that became ineffective were replaced by new peri-urethral balloons and 28% by an artificial urinary sphincter. CONCLUSION: Patients who became continent with adjustable continence therapy (ACT®/proACT®) had a 50 % new surgery probability at 5 years for a loss of efficacy. Radiotherapy seems to be the main risk factor of the efficacy loss. LEVEL OF EVIDENCE: IV.


Assuntos
Próteses e Implantes , Incontinência Urinária/cirurgia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Falha de Prótese , Estudos Retrospectivos , Resultado do Tratamento
2.
Surg Radiol Anat ; 40(7): 729-734, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29589145

RESUMO

OBJECTIVE: In radical cystectomy, the surgeon generally ligates the umbilical artery at its origin. This artery may give rise to several arteries that supply the sexual organs. Our aim was to evaluate pelvic and perineal devascularisation in women after total cystectomy. PATIENTS AND METHODS: We carried out a prospective anatomical and radiological study. We performed bilateral pelvic dissections of fresh adult female cadavers to identify the dividing branches of the umbilical artery. In parallel, we examined and compared the pre- and postoperative imaging investigations [magnetic resonance imaging (MRI) angiography] in patients undergoing cystectomy for benign disease to quantify the loss of pelvic vascularisation on the postoperative images by identifying the occluded arteries. RESULTS: The anatomical study together with the radiological study visualised 35 umbilical arteries (n = 70) with their branching patterns and collateral arteries. The uterine artery originated from the umbilical artery in more than 75% of cases (n = 54) of the internal pudendal artery in 34% (n = 24) and the vaginal artery in 43% (n = 30). The postoperative MRI angiograms showed pelvic devascularisation in four patients. Devascularisation was dependent on the level of surgical ligation. In the four patients with loss of pelvic vascular supply, the umbilical artery had been ligated at its origin. CONCLUSION: The umbilical artery gives rise to various branches that supply the pelvis and perineum. If the surgeon ligates the umbilical artery at its origin during total cystectomy, there is a significant risk of pelvic and perineal devascularisation.


Assuntos
Cistectomia , Angiografia por Ressonância Magnética , Artérias Umbilicais/anatomia & histologia , Artérias Umbilicais/cirurgia , Artéria Uterina/anatomia & histologia , Cadáver , Circulação Colateral , Meios de Contraste , Feminino , Humanos , Ligadura , Pessoa de Meia-Idade , Compostos Organometálicos , Pelve/irrigação sanguínea , Períneo/irrigação sanguínea , Estudos Prospectivos
3.
Prog Urol ; 27(1): 33-37, 2017 Jan.
Artigo em Francês | MEDLINE | ID: mdl-27889177

RESUMO

INTRODUCTION: Morcellation of intravesical adenoma (MIA) is an important part of the endoscopic enucleation procedure. The aim of this study was to analyse the learning curve of the MIA during endoscopic enucleation of the prostate. MATERIAL: We conducted a prospective study of the first 90 patients treated by endoscopic enucleation of the prostate by a single surgeon without previous experience of MIA. The population was divided into 3 consecutive groups of 30 patients. MIA was performed with the morcellator Pinranha (Wolf) and disposable blades (Vmax©). The criteria selected to assess the progress of MIA over time were: duration of MIA (min), the intraoperative complications encountered during MIA and weight morcelleted tissue. The efficacy of MIA was assessed with the ratio weight specimen/MIA duration (min/g) over time. RESULTS: The three groups were comparable in terms of age, ASA score of prostate volume. A significant decrease in the duration of MIA was found between groups 1 and 2 (12 versus 5.5min, P<0.0001), to reach a plateau in the group 3 (3min). A significant increase in the efficiency of MIA was found between group 1 and 2 (5.5 versus 11g/min, P<0.0001), to reach a plateau in the group 3 (20g/min). Bladder injuries were limited (7.7%), superficial and encountered in the early learning phase. CONCLUSION: In our experience, the MIA required a learning curve estimated between 30 and 60 procedures. LEVEL OF EVIDENCE: IV.


Assuntos
Curva de Aprendizado , Morcelação/educação , Morcelação/instrumentação , Hiperplasia Prostática/cirurgia , Idoso , Cistoscopia , Desenho de Equipamento , Humanos , Masculino , Pessoa de Meia-Idade , Morcelação/métodos , Estudos Prospectivos , Bexiga Urinária , Procedimentos Cirúrgicos Urológicos/instrumentação , Procedimentos Cirúrgicos Urológicos/métodos
4.
Prog Urol ; 25(16): 1125-31, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26431746

RESUMO

OBJECTIVE: The aim of this study was to estimate the risk of prostate cancer that led urologists to perform prostate biopsies. PATIENTS AND METHODS: Eight hundred and eight patients had prostate biopsies in 5 tertiary centres in 2010. Following data were collected: age, PSA, DRE, prostate volume, negative prior prostate biopsy and estimated life expectancy (> or <10 years). The risk of prostate cancer was calculated by validated nomogram of PCPT-CRC and SWOP-PRI and correlated with pathological biopsy results. RESULTS: In final analysis, 625 patients were included, 568 (90.9%) had a life expectancy greater than 10 years. Prostate cancer was found in 291 (46.6%) cases. These patients were older (66.7 ± 6.8 vs 64.3 ± 5.6 years, P < 0.001), had higher PSA values (10 ± 7.9 vs 7.7 ± 4.3 ng/mL, P < 0.0001) and the prostate volume decreased (43.8 ± 19.8 vs 51.3 ± 20.7 mL, P < 0.0001) compared with healthy subjects. Digital Rectal Examination was more frequently suspicious in the group of patients with prostate cancer (43.6% vs 18.9%, P < 0.0001). Risk of prostate cancer estimated was 50.6 ± 14% for PCPT-CRC without ATCD, 56.2 ± 12.8% with PCPT-CRC ATCD and 31.2 ± 17.3% for SWOP-PRI. The likelihood of high-risk prostate cancer was 22.4 ± 16.9% with the PCPT-CRC, and 14.8 ± 18.2% with SWOP-PRI. CONCLUSION: This study showed that urologists performed prostate biopsies when the risk of cancer was high.


Assuntos
Tomada de Decisão Clínica , Padrões de Prática Médica , Neoplasias da Próstata/patologia , Urologia , Idoso , Idoso de 80 Anos ou mais , Biópsia , Humanos , Masculino , Pessoa de Meia-Idade , Medição de Risco
5.
Prog Urol ; 23(2): 77-87, 2013 Feb.
Artigo em Francês | MEDLINE | ID: mdl-23352299

RESUMO

INTRODUCTION: Transurethral resection of the prostate (TURP) is the most common surgical procedure in urology and remains the gold standard treatment of complicated benign prostatic hyperplasia or refractory to medical treatment. Routinely used since the 2000s, prostate photoselective vaporization (PVP) with Greenlight(®) laser has been developed to improve the safety of hemostasis in elderly patients and/or with high surgical risk. The purpose of this study was to review the results of PVP from the international literature. MATERIAL AND METHODS: [corrected] A systematic review of the literature on the research base Pubmed (http://www.ncbi.nlm.nih.gov/) was performed using the keywords benign prostatic hyperplasia; greenlight; photovaporisation; Laser; IPSS score; endoscopicsurgery; morbidity; complication. Prospective and retrospective studies in English and French were selected from its first use in 1998. Finally, we looked for studies that reported at least one of the following items: surgical technique; operative data; complications; anatomical and functional results and/or direct comparison between PVP and TURP. RESULTS: Regardless the PVP technique used to treat adenoma and identify the limits of the prostatic capsule, some parameters are well defined (sweepspeed, angle and distance of the fiber with the tissue) but others are still debated (number of joules per volume, when do we have to stop the PVP) and are reported in a heterogeneous manner due to the different generators. Versus TURP, PVP would offer the same functional results in the medium term but with a lower risk of per- and postoperative bleeding. The study of the risk of erectile dysfunction (ED) after PVP is made difficult due to the heterogeneity of DE assessment and study populations. However, PVP does not seem associated with an increased risk of ED versus TURP. The lack of histological material should lead to preoperative individual screening of prostate. The economy generated by PVP regarding the decrease in average length of stay has been clearly identified in Australia, Canada, Switzerland and USA. Studies will be published soon on French economic model. CONCLUSION: PVP with Greenlight(®) laser appears to be a safe and effective technique. With the new generator XPS, the PVP technique reaches maturity. Its development will certainly lead to a long-term evaluation with high levels of evidence based.


Assuntos
Terapia a Laser , Prostatectomia/métodos , Hiperplasia Prostática/cirurgia , Idoso , Medicina Baseada em Evidências , Humanos , Terapia a Laser/métodos , Masculino , Prognóstico , Fatores de Tempo , Ressecção Transuretral da Próstata/métodos , Resultado do Tratamento
6.
Prog Urol ; 23(10): 869-76, 2013 Sep.
Artigo em Francês | MEDLINE | ID: mdl-24034799

RESUMO

INTRODUCTION: The aim of this study was to analyze the XPS laser learning curve of one single surgeon with no previous experience of PVP and the impact of the use of reel time transrectal ultrasound (TRUS) monitoring. MATERIALS AND METHODS: Retrospective analysis of the first 100 patients: group 1 (1st-49th patient without TRUS) and group 2 (50th-100th with TRUS). The learning curve was analyzed through technical variables: vaporization time/intervention time (VT/IT) (%), energy delivered (J)/prostate volume (J/mL) and delivered energy (J/s or Watt), peroperative conversion into monopolar transurethral resection, postoperative complication, duration of catheterization and hospitalization and evolution of International Prostate Symptom Score (IPSS), PSA level, prostate residual volume and Qmax. Relationships between variables were evaluated by analysing the covariance (R 2 software. 14.2). RESULTS: A significant increase in VT/IT (P=0.0001) and the energy delivered per mL prostate (P=0.043) was reported in group 1. The average energy delivered per second was significantly higher in group 2 (P=0.0016). No difference was observed in terms of intra- or postoperative complication and catheterization time. The duration of hospitalization was significantly shorter in group 2 (P=0.03). The use of TRUS was associated with a gain of energy delivered by prostate volume at the end of learning curve (P=0.018). Prostate residual volume was significantly lower in the group 2 (P=0.0004). CONCLUSION: In our experience, 50 procedures are required to achieve the learning curve of PVP. The use of reel time TRUS would increase the energy delivered by prostate volume.


Assuntos
Fotocoagulação a Laser/métodos , Próstata/diagnóstico por imagem , Hiperplasia Prostática/cirurgia , Ultrassonografia de Intervenção , Idoso , Humanos , Curva de Aprendizado , Tempo de Internação , Masculino , Duração da Cirurgia , Próstata/cirurgia , Hiperplasia Prostática/diagnóstico por imagem , Estudos Retrospectivos
7.
Prog Urol ; 23(5): 347-55, 2013 Apr.
Artigo em Francês | MEDLINE | ID: mdl-23545010

RESUMO

OBJECTIVE: We explored the characteristics of a sample of men who had undergone a biopsy in clinical practice in France and evaluated initial treatment choice in men with a positive biopsy. METHODS: This was a multi-centre, retrospective chart review including men who had undergone a biopsy in France. Clinical variables were collected using an electronic data capture system. RESULTS: Eight hundred and eight men were included; 632 men (78%) had an initial biopsy and 176 men (22%) had one or more repeat biopsy. The mean age was 64 years and 9% of men were 75 years or more. The mean (median) PSA was 11.6 (7.0) ng/mL; 25% of men had a PSA greater than 10 ng/mL. Twenty-eight percent of men had a suspicious DRE. A total of 52% of men had a positive initial and 26% a positive repeat biopsy. One hundred and eleven patients (34%) had low-risk PCa (stage T1c-2a, PSA<10 ng/mL, Gleason sum<7) and 195 (59%) were at intermediate/high risk of disease progression. The most common treatment was radical therapy (54% of patients), even in men with low-risk PCa (40% of patients). A total of 38% of low-risk patients chose active surveillance. CONCLUSIONS: The French biopsy sample appeared to be at a relatively high risk of having PCa at initial biopsy. Radical therapy was the most common treatment choice in men with a positive biopsy. In patients with low-risk PCa, radical therapy and active surveillance were used most often and to the same extent.


Assuntos
Neoplasias da Próstata/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , França , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/patologia , Estudos Retrospectivos
8.
Prog Urol ; 22(12): 701-4, 2012 Oct.
Artigo em Francês | MEDLINE | ID: mdl-22999116

RESUMO

PURPOSE: The aim of the study was to evaluate if only ureteral stent removing after complicated renal colic (RC) could prevent from complementary treatment (shock-wawe lithortripsy or ureteroscopy). PATIENTS AND METHODS: Data from 95 patients, 39 women and 56 men, who had an ureteral stent for complicated RC from 2005 to 2010 were retrospectively collected. Mean age was 46.4 ± 17.2 years. After the initial management, another hospitalization was organized where patients had ureteral stent removing under local anesthesia, then an abdominal CT-scan without injection and complementary treatment of ureteral stones (none or ESWL or ureteroscopy). Parameters studied were age, sex, stone size, location of calcul. Quantitative values were compared with Student's t test. Qualitative values were compared with the Chi(2). P<0.05 was considered statistically significant. RESULTS: Mean duration between the two hospitalizations were 1.58 ± 1.84 months. Sixty-one patients (64.2%) had no more urolithiasis. In these patients, mean size of urolithiasis was 5.85 ± 2.33 mm. Location of urolithiasis in distal, mild and proximal ureter was 77%, 3% and 20% respectively. Thirty-four patients (35.8%) had persistant lithiasis after CT-scan. Location of stone in distal, mild and proximal ureter was 17.5%, 5.8% and 76.7% respectively. CONCLUSION: After management of complicated renal colic by ureteral stent, 64% of patients had spontaneous elimination of stones after removing of ureteral stent, especially in women and pelvic ureter.


Assuntos
Cólica Renal/terapia , Stents , Urolitíase/terapia , Feminino , Humanos , Litotripsia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Ureteroscopia
9.
Nat Med ; 6(3): 327-31, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10700236

RESUMO

Persistence of hepatocytes transplanted into the same or related species has been established. The long-term engraftment of human hepatocytes into rodents would be useful for the study of human viral hepatitis, where it might allow the species, technical and size limitations of the current animal models to be overcome. Although transgenic mice expressing the hepatitis B virus (HBV) genome produce infectious virus in their serum, the viral life cycle is not complete, in that the early stages of viral binding and entry into hepatocytes and production of an episomal transcriptional DNA template do not occur. As for hepatitis delta virus (HDV), another cause of liver disease, no effective therapy exists to eradicate infection, and it remains resistant even to recent regimens that have considerably changed the treatment of HBV (ref. 13). Here, we demonstrate long-term engraftment of primary human hepatocytes transplanted in a matrix under the kidney capsule of mice with administration of an agonistic antibody against c-Met. These mice were susceptible to HBV infection and completion of the viral life cycle. In addition, we demonstrate super-infection of the HBV-infected mice with HDV. Our results describe a new xenotransplant model that allows study of multiple aspects of human hepatitis viral infections, and may enhance studies of human liver diseases.


Assuntos
Transplante de Células , Vírus da Hepatite B/isolamento & purificação , Hepatite B/patologia , Hepatite D/patologia , Vírus Delta da Hepatite/isolamento & purificação , Fígado/citologia , Transplante Heterólogo , Animais , Modelos Animais de Doenças , Hepatite B/transmissão , Hepatite D/transmissão , Humanos , Fígado/patologia , Fígado/virologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Proteínas Proto-Oncogênicas c-met/imunologia , Fatores de Tempo
10.
Prog Urol ; 20 Suppl 1: S50-3, 2010 Mar.
Artigo em Francês | MEDLINE | ID: mdl-20493446

RESUMO

Fluorescence cystoscopy improves the detection of non-muscle-invasive bladder cancer, particularly carcinoma in situ, and reduces recurrence. The technique is well tolerated with few side effects. Guidelines recommend fluorescence cystoscopy in multifocal tumors, tumors >3cm, early recurrence, High grade cytology, follow-up of high-risk bladder cancer (T1G3 and CIS).


Assuntos
Ácido Aminolevulínico/análogos & derivados , Radioisótopos de Carbono , Cistoscopia/métodos , Neoplasias da Bexiga Urinária/diagnóstico por imagem , Fluorescência , Humanos , Guias de Prática Clínica como Assunto , Cintilografia
12.
Prog Urol ; 22(6): 339-43, 2010 May.
Artigo em Francês | MEDLINE | ID: mdl-22541903

RESUMO

PURPOSE: To evaluate the long term outcome of renal transplant in patients with a neural tube defect causing voiding dysfunctions. PATIENT AND METHODS: Between 1993 and 2010, 18 cadaveric renal transplants were performed in 16 patients (5 females and 11 males) older than 15 years with a neural tube defect and voiding dysfunction. RESULTS: The patients had dialysis since the mean age of 27.4 and have been transplanted at the mean age of 32.2. The survival rate of the first kidney transplant was 93.75% at 1 year and 63.3% at 5 and 10 years respectively. With a mean follow-up of 6.67 years, 11 out of 16 first transplants remained functional (68.75%) The median survival of the first transplants was 13.52 years. At the end of the follow-up, 13 out of 18 transplants were still functional (72.2%). The mean serum creatinine level was 123.9 micromol/l with a mean glomerular filtration rate estimated by the simplified MDRD formula of 67 ml/min for the 13 still functional transplants. Before transplantation, 66% of patients had a neuro-urologic assessment versus 100% thereafter. CONCLUSION: Renal transplantation in patients with neural tube defect is feasible without surgical particularities to those of other renal failure causes. These type of patients represented less than 1% of the followed cohort with an average graft survival rate of 63.3% at five and 10 years. The median survival time of the first graft was 13.52 years.


Assuntos
Falência Renal Crônica/etiologia , Falência Renal Crônica/cirurgia , Transplante de Rim , Defeitos do Tubo Neural/complicações , Adulto , Feminino , Seguimentos , Humanos , Masculino , Fatores de Tempo , Resultado do Tratamento
13.
J Cell Biol ; 46(3): 518-32, 1970 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-4349130

RESUMO

Section freeze-dry radioautography has been used to examine the intrarenal distribution of a water-soluble organic acid (para-aminohippuric acid (PAH-3H)) under constant-infusion, steady-state conditions in mouse and rat kidney in vivo. The technique described here has the following advantages: (a) Sectioning and freeze-drying are accomplished in a closed cryostat at temperatures below -40 degrees C; (b) Handling of the section is facilitated by mounting of the section-to-be on adhesive-coated Saran Wrap prior to cutting; (c) Unembedded freeze-dried sections are attached to photographic film at ambient temperature in the dark room; (d) Fixation follows completion of radioautographic exposure and precedes photographic development; (e) Permanent close contact is maintained between tissue and film. Morphologic preservation compared favorably with that obtained by optimal fixation techniques, which, however, permit diffusion. Cellular accumulation of PAH-3H during secretion was demonstrated in the proximal tubule under steady-state conditions in vivo. The cellular concentration of PAH-3H was uniform throughout the length of the proximal tubule in mouse and rat kidney.


Assuntos
Ácidos Aminoipúricos/análise , Autorradiografia , Liofilização , Túbulos Renais/citologia , Animais , Núcleo Celular , Feminino , Histocitoquímica , Corpos de Inclusão , Túbulos Renais/análise , Métodos , Microscopia , Microscopia de Contraste de Fase , Microtomia , Mitocôndrias , Plásticos , Ratos , Trítio
16.
J Mol Biol ; 226(1): 1-6, 1992 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-1377751

RESUMO

Primer tRNA regions involved in the interactions between human immunodeficiency virus reverse transcriptase (HIV RT) and tRNA(Lys) were studied by digestion of primer with pancreatic ribonuclease in the presence or absence of HIV RT. The acceptor stem of tRNA(Lys) is not noticeably protected against nuclease action in the presence of HIV RT, while this enzyme clearly protects part of the anticodon and dihydrouridine loops of tRNA(Lys). The acceptor stem of primer tRNA was digested by RNase A only in the presence of the retroviral enzyme, suggesting a partial destabilization of this region by the HIV RT. Synthetic oligoribonucleotides, corresponding to the anticodon and the dihydrouridine loops, inhibited strongly reverse transcription, confirming the strong interaction of these tRNA regions with the enzyme.


Assuntos
HIV/enzimologia , Oligorribonucleotídeos/metabolismo , RNA de Transferência de Lisina/metabolismo , DNA Polimerase Dirigida por RNA/metabolismo , Sequência de Bases , Cinética , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Oligorribonucleotídeos/genética , RNA de Transferência de Lisina/genética , Ribonuclease Pancreático/metabolismo
17.
J Mol Biol ; 204(1): 217-20, 1988 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-3216393

RESUMO

Using an extract of nuclei from the estrogen-responsive human breast cancer cell line MCF-7, protein-DNA complexes were assembled in vitro at the 5' end of the Xenopus laevis vitellogenin gene B2 that is normally expressed in liver after estrogen induction. The complexes formed were analyzed by electron microscopy after labeling by the indirect colloidal gold immunological method using a monoclonal antibody specific for the human estrogen receptor. As identified by its interaction with protein A-gold, the antibody was found linked to two protein-DNA complexes, the first localized at the estrogen responsive element of the gene and the second in intron I, thus proving a direct participation of the receptor in these two complexes. The procedure used allows the visualization and rapid localization of specific transcription factors bound in vitro to a promoter or any other gene region.


Assuntos
DNA/análise , Íntrons , Receptores de Estrogênio/análise , Vitelogeninas/genética , Xenopus laevis/genética , Animais , Linhagem Celular , Estrogênios/metabolismo , Genes , Humanos , Imuno-Histoquímica , Substâncias Macromoleculares , Microscopia Eletrônica
18.
J Mol Biol ; 299(4): 853-8, 2000 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-10843841

RESUMO

Immuno-electron microscopy was used to visualize the structure of reconstituted chromatin after in vitro transcription by purified T7 RNA polymerase. T7 RNA polymerase disrupts the nucleosomal structure in the transcribed region. This disruption is not influenced by the template, linear or supercoiled, and the presence or absence of nucleosomal positioning sequences in the transcribed region. In this study, we used monoclonal autoantibodies reacting with the nucleosome core particles and epitopes within several regions of the four different core histones. Some of the residues recognized by the autoantibodies are accessible on the surface of the nucleosomes and some are more internal and therefore less exposed at the surface. We show that the loss of the nucleosomal configuration during transcription is due to the loss of histone/DNA binding and that at least part of the histones are transferred to the nascent RNA chains. Consequently, after in vitro transcription by T7 RNA polymerase, the nucleosomal template does not conserve its original configuration, and no interaction of antigen/antibodies is observed anymore in the region that has been transcribed. Therefore, we conclude that in our in vitro transcription assay, nucleosomes are detached from the template, and not simply unfolded with histones remaining attached to the DNA.


Assuntos
Histonas/metabolismo , Histonas/ultraestrutura , Nucleossomos/metabolismo , Nucleossomos/ultraestrutura , Transcrição Gênica , Animais , Anticorpos Monoclonais/imunologia , Autoanticorpos/imunologia , DNA Super-Helicoidal/química , DNA Super-Helicoidal/genética , DNA Super-Helicoidal/metabolismo , DNA Super-Helicoidal/ultraestrutura , Proteínas de Ligação a DNA/imunologia , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/ultraestrutura , RNA Polimerases Dirigidas por DNA/metabolismo , Epitopos/imunologia , Histonas/imunologia , Camundongos , Microscopia Imunoeletrônica , Conformação Molecular , Nucleossomos/química , Nucleossomos/genética , Plasmídeos/química , Plasmídeos/genética , Plasmídeos/metabolismo , Plasmídeos/ultraestrutura , Ligação Proteica , RNA Ribossômico 5S/biossíntese , RNA Ribossômico 5S/genética , RNA Ribossômico 5S/metabolismo , RNA Ribossômico 5S/ultraestrutura , Proteínas de Ligação a RNA/imunologia , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/ultraestrutura , Moldes Genéticos , Transcrição Gênica/genética , Proteínas Virais
19.
Mol Endocrinol ; 3(10): 1596-609, 1989 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2608051

RESUMO

A structural and functional analysis of the 5'-end region of the Xenopus laevis vitellogenin gene A1 revealed two transcription initiation sites located 1.8 kilobases apart. A RNA polymerase II binding assay indicates that both promoters form initiation complexes efficiently. In vitro, using a transcription assay derived from a HeLa whole-cell extract, the upstream promoter is more than 10-fold stronger than the downstream one. In contrast, both promoters have a similar strength in a HeLa nuclear extract. In vivo, that is in estrogen-stimulated hepatocytes, it is the downstream promoter homologous to the one used by the other members of the vitellogenin gene family, which is 50-fold stronger than the upstream promoter. Thus, if functional vitellogenin mRNA results from this latter activity, it would contribute less than 1% to the synthesis of vitellogenin by fully induced Xenopus hepatocytes expressing the four vitellogenin genes. In contrast, both gene A1 promoters are silent in uninduced hepatocytes. Transfection experiments using the Xenopus cell line B3.2 in which estrogen-responsiveness has been introduced reveal that the strong downstream promoter is controlled by an estrogen responsive element (ERE) located 330 bp upstream of it. The upstream promoter can also be controlled by the same ERE. Since the region comprising the upstream promoter is flanked by a 200 base pair long inverted repeat with stretches of homology to other regions of the X. laevis genome, we speculate that it might have been inserted upstream of the vitellogenin gene A1 by a recombination event and consequently brought under control of the ERE lying 1.5 kilobases downstream.


Assuntos
Estrogênios/farmacologia , Regiões Promotoras Genéticas , Vitelogeninas/genética , Animais , Sequência de Bases , Núcleo Celular/enzimologia , Núcleo Celular/ultraestrutura , DNA/genética , DNA/ultraestrutura , Feminino , Células HeLa , Humanos , Técnicas In Vitro , Dados de Sequência Molecular , RNA Polimerase II/genética , RNA Mensageiro/genética , Endonucleases Específicas para DNA e RNA de Cadeia Simples , Transcrição Gênica , Transfecção , Xenopus laevis
20.
Gene ; 200(1-2): 91-8, 1997 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-9373142

RESUMO

The murine malaria parasite Plasmodium berghei contains a plastid-like extrachromosomal genome. This genome is 30.7 kb in size and is transcriptionally active as shown by RT-PCR. DNA sequence analysis of the genome reveals 69.9-95.5% homology to sequences of the 35-kb extrachromosomal circle found in the human malaria species Plasmodium falciparum. Homologous sequences include regions of genes for the ssu-rRNA, lsu-rRNA, rpo B and clusters of t-RNAs. Sequence variation between the two Plasmodium species exists in the non-coding interspacing regions. A physical map has been constructed for the P. berghei circle, indicating the EcoRI and HindIII restriction sites as well as the arrangement of the rRNA, rpo B and tRNA genes. Arrangement of these genes is similar to that found on the P. falciparum 35-kb circle. The P. berghei circular element is distinct from the mitochondrial 6-kb DNA of both the murine and the human Plasmodium species. Preliminary results indicate that the circle may be a useful target for drug therapy.


Assuntos
DNA de Protozoário/química , Plasmodium berghei/genética , Animais , Sequência de Bases , DNA Mitocondrial/química , DNA Mitocondrial/genética , DNA de Protozoário/genética , DNA de Protozoário/ultraestrutura , Variação Genética , Humanos , Camundongos , Plasmodium falciparum/genética , Plastídeos/ultraestrutura , Reação em Cadeia da Polimerase , RNA de Protozoário/biossíntese , Mapeamento por Restrição , Homologia de Sequência do Ácido Nucleico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA