Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Eur J Clin Microbiol Infect Dis ; 36(7): 1269-1278, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28197729

RESUMO

Bacterial vaginosis (BV) is the leading cause of vaginal discharge and is associated with the facultative Gram-variable bacterium Gardnerella vaginalis, whose population structure consists of four clades. Our goal was to determine if these clades differ with regard to abundance during BV. We performed a short-term longitudinal study of BV. Patients were evaluated according to the Amsel criteria and Nugent scoring at initial diagnosis, immediately after treatment and at a 40- to 45-day follow-up visit. G. vaginalis clade abundance was determined by quantitative real-time polymerase chain reactions (qPCRs). Among all specimens, the abundance of clades 1 and 4 were higher than that of clades 2 and 3 (P < 0.001). In general, the abundance of each clade increased with the degree of vaginal dysbiosis, as determined by the Nugent score and was greater in women with Amsel 4 compared with those with Amsel 0. Only clade 1 abundance was greater when Amsel 0 or 1 specimens were compared with Amsel 2 or 3 specimens (P < 0.01). Following antimicrobial treatment, abundance of clades 1 (P < 0.001) and 4 (P < 0.05) decreased regardless of the clinical and microbiological outcome, whereas clade 2 only decreased in women who had a sustained treatment response for 40-45 days (P < 0.01). Recurrent BV was characterized by post-treatment increases of clade 1 and 2 (P < 0.01). Clades 1 and 4 predominate in vaginal specimens. Clade abundance differs with regard to the Nugent score, the Amsel criteria, and response to therapy and BV recurrence.


Assuntos
Gardnerella vaginalis/crescimento & desenvolvimento , Dinâmica Populacional , Vaginose Bacteriana/microbiologia , Adolescente , Adulto , Carga Bacteriana , Feminino , Gardnerella vaginalis/classificação , Gardnerella vaginalis/genética , Genótipo , Humanos , Estudos Longitudinais , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real , Adulto Jovem
2.
Proc Natl Acad Sci U S A ; 113(51): 14674-14679, 2016 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-27930293

RESUMO

Diet is central for understanding hominin evolution, adaptation, and environmental exploitation, but Paleolithic plant remains are scarce. A unique macrobotanical assemblage of 55 food plant taxa from the Acheulian site of Gesher Benot Ya'aqov, Israel includes seeds, fruits, nuts, vegetables, and plants producing underground storage organs. The food plant remains were part of a diet that also included aquatic and terrestrial fauna. This diverse assemblage, 780,000 y old, reflects a varied plant diet, staple plant foods, environmental knowledge, seasonality, and the use of fire in food processing. It provides insight into the wide spectrum of the diet of mid-Pleistocene hominins, enhancing our understanding of their adaptation from the perspective of subsistence. Our results shed light on hominin abilities to adjust to new environments, facilitating population diffusion and colonization beyond Africa. We reconstruct the major vegetal foodstuffs, while considering the possibility of some detoxification by fire. The site, located in the Levantine Corridor through which several hominin waves dispersed out of Africa, provides a unique opportunity to study mid-Pleistocene vegetal diet and is crucial for understanding subsistence aspects of hominin dispersal and the transition from an African-based to a Eurasian diet.


Assuntos
Dieta , Fósseis , Hominidae/fisiologia , África , Animais , Arqueologia , Ecologia , Incêndios , Israel , Modelos Estatísticos , Paleontologia , Plantas , Dinâmica Populacional , Estações do Ano , Sementes , Especificidade da Espécie
3.
Clin Microbiol Infect ; 20(8): O516-23, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24450778

RESUMO

The study aims were: (i) to define the prevalence of and risk factors for colonization by extended spectrum ß-lactamase (ESBL) -producing Enterobacteriaceae (EPE) among healthcare workers (HCWs) and family members (FMs) of EPE-colonized patients in rehabilitation units and (ii) to compare EPE isolates from these three groups. The study included 286 FMs of 194 EPE-carrying patients identified in five rehabilitation units located in Israel, Italy, France and Spain. The EPE were detected in rectal swabs from 26 (9%) of 286 FMs screened. In multivariate analyses, older age of FM, greater mean number of hours spent with the patient, being a daughter or a female spouse of a patient, and chronic lung disease of the patient were significantly associated with carriage in the FM. Escherichia coli was the most common organism (76%), followed by Klebsiella pneumoniae (19%). Isolates were typed by pulsed field gel electrophoresis and multilocus sequence typing, and ESBLs were identified by PCR sequencing. A comparison of paired species isolates from FMs and their respective patient showed that 17 of 23 strains were indistinguishable. EPE were detected in 35 (3.5%, E. coli = 34) of the 1001 HCWs screened. Feeding patients was associated with EPE carriage by HCWs. Only 7 of 23 E. coli subclones cultured from HCWs were also represented among 376 patient-derived ESBL-producing E. coli isolates from the same rehabilitation units. In Spain, a higher proportion of HCWs and FMs were ESBL carriers than elsewhere (p <0.05). In conclusion, the molecular and epidemiological data suggest that FMs are at higher risk of EPE acquisition from their relative patients than HCWs.


Assuntos
Portador Sadio/epidemiologia , Infecções por Enterobacteriaceae/epidemiologia , Enterobacteriaceae/enzimologia , Família , Pessoal de Saúde , Centros de Reabilitação , beta-Lactamases/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Portador Sadio/transmissão , DNA Bacteriano/química , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Enterobacteriaceae/classificação , Enterobacteriaceae/genética , Enterobacteriaceae/isolamento & purificação , Infecções por Enterobacteriaceae/transmissão , Escherichia coli , Europa (Continente)/epidemiologia , Fezes/microbiologia , Feminino , Genótipo , Humanos , Klebsiella pneumoniae , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Tipagem de Sequências Multilocus , Reação em Cadeia da Polimerase , Prevalência , Estudos Prospectivos , Adulto Jovem
4.
Emerg Med J ; 27(1): 5-7, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20028996

RESUMO

BACKGROUND: The use of rapid antigen tests to triage specimens for polymerase chain reaction (PCR) testing from emergency department patients with influenza-like illness during surveillance for novel influenza viruses has been suggested. OBJECTIVE: To measure the observed sensitivity and specificity for a widely used rapid antigen test (Binax) using a PCR-based assay (Medical Diagnostic Laboratories). METHODS: Nasopharyngeal samples were taken with flocked swabs (Copan Diagnostics) from patients presenting to the emergency department of a community hospital. Samples were analysed using a rapid antigen and a PCR-based test. PCR testing was used as the criterion reference. Sensitivity and specificity were calculated for influenza and influenza A. Positive predictive values were calculated over a range of possible prevalence. RESULTS: Samples from 566 unique patients were tested using both methods. Sensitivity was 69.1% (95% CI 58.9% to 78.1%) and specificity was 97.7% (95% CI 95.8% to 98.8%) for the detection of any influenza and 75.3% (95% CI 64.7% to 84.0%) and 97.8% (95% CI 95.9% to 98.9%), respectively, for influenza A only. The resultant positive predictive value ranges from 23% to 77% when the prevalence ranges from 1% to 10%. CONCLUSION: When planning early outbreak surveillance, provision of adequate PCR testing capacity rather than triaging specimens using rapid antigen testing for influenza is advisable.


Assuntos
Antígenos Virais/análise , Imunoensaio , Influenza Humana/diagnóstico , Orthomyxoviridae/isolamento & purificação , Reação em Cadeia da Polimerase , Humanos , Nasofaringe/virologia , Orthomyxoviridae/genética , Orthomyxoviridae/imunologia , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Método Simples-Cego , Turquia
5.
Eur J Clin Microbiol Infect Dis ; 28(11): 1399-403, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19639348

RESUMO

Uropathogenic Escherichia coli (UPEC) is the primary cause of urinary tract infections (UTIs) in adult women, which are increasingly refractory to antimicrobial treatment. UPEC colonizes the vagina prior to causing a UTI. Our hypothesis was that the vaginal flora would be enriched in UPEC and therefore have a greater prevalence of non-susceptibility relative to the rectal flora. We used disk diffusion to determine the antimicrobial susceptibilities of 100 cervico-vaginal E. coli (CVEC) and 100 rectal E. coli (REC) isolates from 200 different patients. Phylogeny, plasmid replicons, and antimicrobial resistance genes were detected by polymerase chain reaction (PCR). There were no significant differences between CVEC and REC, and the overall levels of non-susceptibility were 39.5% for ampicillin (AM), 11.5% for ampicillin-sulbactam (SAM), 11.5% for trimethoprim-sulfamethoxazole (SXT), 5% for ciprofloxacin (CIP), 2.5% for nitrofurantoin (F/M), 0.5% for ceftazidime (CAZ), 0.5% for cefotaxime (CTX), and 0% for fosfomycin (FOS). SXT non-susceptibility was associated with phylogenetic groups A and D compared with B2. AM and SXT non-susceptibility was associated with plasmid carriage. The vaginal flora is not enriched in antimicrobial non-susceptibility relative to the rectal flora. However, antimicrobial non-susceptibility was associated with phylogeny and plasmid carriage.


Assuntos
Antibacterianos/farmacologia , Colo do Útero/microbiologia , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Reto/microbiologia , Vagina/microbiologia , Adulto , DNA Bacteriano/genética , Escherichia coli/classificação , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Feminino , Genes Bacterianos , Genótipo , Humanos , Testes de Sensibilidade Microbiana , Filogenia , Plasmídeos/análise , Reação em Cadeia da Polimerase , Adulto Jovem
8.
Science ; 312(5778): 1372-4, 2006 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-16741119

RESUMO

It is generally accepted that the fig tree was domesticated in the Near East some 6500 years ago. Here we report the discovery of nine carbonized fig fruits and hundreds of drupelets stored in Gilgal I, an early Neolithic village, located in the Lower Jordan Valley, which dates to 11,400 to 11,200 years ago. We suggest that these edible fruits were gathered from parthenocarpic trees grown from intentionally planted branches. Hence, fig trees could have been the first domesticated plant of the Neolithic Revolution, which preceded cereal domestication by about a thousand years.


Assuntos
Agricultura/história , Ficus , Ficus/anatomia & histologia , Ficus/genética , Frutas/anatomia & histologia , Heterozigoto , História Antiga , Homozigoto , Humanos , Israel , Oriente Médio
10.
Eur J Gynaecol Oncol ; 25(3): 308-10, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15171306

RESUMO

OBJECTIVE: The aim of the current study was to examine the pathological characteristics of ovarian cancer occurring in women with previous hysterectomy. METHODS: Newly diagnosed cases of ovarian primary epithelial or primary peritoneal cancer, operated on in our department between January 2000 and December 2002, were included in this retrospective study. The patients were divided into two groups, group I included eight patients with ovarian cancer and previous hysterectomy, and group II comprised 70 patients with ovarian or primary peritoneal cancer, but without previous hysterectomy. RESULTS: There was no significant difference between the eight patients with ovarian cancer and previous hysterectomy and the 70 patients without previous hysterectomy considering the patients' characteristics. Conversely, there was a difference between the two study groups regarding the histology of the tumor, its grade and the stage of the disease. All patients with ovarian cancer and previous hysterectomy had poorly differentiated mixed epithelial or undifferentiated tumors. Nevertheless, only 25% of these patients were diagnosed in Stage IIIC. CONCLUSION: It seems that besides reducing the risk of further ovarian cancer, hysterectomy also causes a change in the main histological sub-group of ovarian cancer, that develops in patients with previous hysterectomy. The greatest protective effect was observed for serous ovarian tumors.


Assuntos
Histerectomia , Neoplasias Ovarianas/epidemiologia , Neoplasias Ovarianas/patologia , Carcinoma/epidemiologia , Carcinoma/etiologia , Carcinoma/patologia , Carcinoma Endometrioide/epidemiologia , Carcinoma Endometrioide/etiologia , Carcinoma Endometrioide/patologia , Carcinoma Papilar/epidemiologia , Carcinoma Papilar/etiologia , Carcinoma Papilar/patologia , Estudos de Casos e Controles , Feminino , Humanos , Israel/epidemiologia , Prontuários Médicos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Ovarianas/etiologia , Estudos Retrospectivos
11.
Science ; 304(5671): 725-7, 2004 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-15118160

RESUMO

The presence of burned seeds, wood, and flint at the Acheulian site of Gesher Benot Ya'aqov in Israel is suggestive of the control of fire by humans nearly 790,000 years ago. The distribution of the site's small burned flint fragments suggests that burning occurred in specific spots, possibly indicating hearth locations. Wood of six taxa was burned at the site, at least three of which are edible--live, wild barley, and wild grape.


Assuntos
Arqueologia , Incêndios , Hominidae , Animais , Grão Comestível , Fraxinus , Frutas , Sedimentos Geológicos , Humanos , Israel , Olea , Poaceae , Sementes , Madeira
12.
Proc Natl Acad Sci U S A ; 101(9): 2692-5, 2004 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-14976246

RESUMO

The Agricultural Revolution in Western Asia, which took place some 11,000 years ago, was a turning point in human history [Childe, V. G. (1952) New Light on the Most Ancient East (Routledge & Kegan Paul, London)]. In investigating the cultural processes that could have led from gathering to intentional cultivation, various authors have discussed and tested wild cereal harvesting techniques. Some argue that Near Eastern foragers gathered grains by means of sickle harvesting, uprooting, plucking (hand stripping), or beating into baskets [Hillman, G. C. & Davies, M. S. (1999) in Prehistory of Agriculture: New Experimental and Ethnographic Approaches, ed. Anderson, P. (The Institute of Archaeology, University of California, Los Angeles), pp. 70-102]. During systematic experiments, we found that archaeobotanical data from regional Neolithic sites support ground collection of grains by early hunter-gatherers. Ground collecting suits the natural shattering of wild species that ripen and drop grains at the beginning of summer. We show that continual collection off the ground from May to October would have provided surplus grains for deliberate sowing in more desirable fields, and facilitate the transition to intentional cultivation. Because ground gathering enabled collectors to observe that fallen seeds are responsible for the growth of new plants in late fall, they became aware of the profitability of sowing their surplus seeds for next year's food. Ground collecting of wild barley and wild wheat may comprise the missing link between seed collecting by hunter-gatherers and cereal harvesting by early farmers.


Assuntos
Agricultura/história , Grão Comestível , Arqueologia , Botânica , Grão Comestível/crescimento & desenvolvimento , História Antiga
13.
Arch Neurol ; 58(9): 1357-63, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11559306

RESUMO

OBJECTIVES: To investigate Bartonella henselae as a potential human tick-borne pathogen and to evaluate its role as a coinfecting agent of the central nervous system in the presence of neuroborreliosis. DESIGN: Case report study. SETTING: A primary health care center in Flemington, NJ, and the Department of Research and Development at Medical Diagnostic Laboratories LLC in Mt Laurel, NJ. SUBJECTS: Two male patients (aged 14 and 36 years) and 2 female patients (aged 15 and 30 years, respectively) with a history of tick bites and Lyme disease. MAIN OUTCOME MEASURES: Laboratory and diagnostic findings before and after antimicrobial therapy. RESULTS: Patients residing in a Lyme-endemic area of New Jersey with ongoing symptoms attributed to chronic Lyme disease were evaluated for possible coinfection with Bartonella species. Elevated levels of B henselae-specific antibodies were found in these patients using the immunofluorescent assay. Bartonella henselae-specific DNA was detected in their blood. None of these patients exhibited the clinical characteristics of cat-scratch disease. Findings of cerebrospinal fluid analysis revealed the presence of both B henselae- and Borrelia burgdorferi-specific DNA. Bartonella henselae-specific DNA was also detected in live deer ticks obtained from the households of 2 of these patients. CONCLUSIONS: Our data implicate B henselae as a potential human tick-borne pathogen. Patients with a history of neuroborreliosis who have incomplete resolution of symptoms should be evaluated for B henselae infection.


Assuntos
Bartonella henselae/isolamento & purificação , Grupo Borrelia Burgdorferi/isolamento & purificação , Doença da Arranhadura de Gato/microbiologia , Neuroborreliose de Lyme/microbiologia , Adulto , Bartonella henselae/genética , Grupo Borrelia Burgdorferi/genética , Doença da Arranhadura de Gato/diagnóstico , Pré-Escolar , DNA Bacteriano/análise , Feminino , Humanos , Neuroborreliose de Lyme/diagnóstico , Masculino
14.
Hum Reprod ; 14(12): 3000-1, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10601086

RESUMO

We report a rare clinical case of recurrent isolated torsion of the Fallopian tube. An 18 year old woman presented with acute right lower quadrant pain, nausea and vomiting. Torsion of the Fallopian tube was detected by laparoscopy and detorsion was performed. Two years later, a second similar episode of pelvic pain recurred. Having in mind the first episode, diagnosis was facilitated and detorsion was performed in accordance with the patient's wishes. However, the dilemma of ideal management of recurrent cases of torsion of the same tube remains open for discussion. The possibility of torsion of the Fallopian tube and recurrent torsion of the tube, although rare, should be considered in any patient with acute onset of lower abdominal pain.


Assuntos
Doenças das Tubas Uterinas/patologia , Doenças das Tubas Uterinas/cirurgia , Laparoscopia , Adolescente , Feminino , Humanos , Recidiva , Anormalidade Torcional
15.
Hum Exp Toxicol ; 16(9): 485-94, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9306134

RESUMO

1. In this study we hypothesized that in individuals with certain genetic makeup, MTBE, benzene or their metabolites act as adducts and may induce programmed cell death. 2. Our study involved a group of 60 male and female subjects who were exposed to MTBE and benzene-contaminated water concentrations up to 76 PPB for MTBE and 14 PPB for benzene, for a period of 5 to 8 years. For comparison, we recruited a control group consisting of 32 healthy males and females with similar age distribution and without a history of exposure to MTBE or benzene. 3. Peripheral blood lymphocytes (PBL) of both groups were tested for the percentage of apoptotic cells and cell cycle progression using flow cytometry. 4. When apoptotic lymphocytes from exposed individuals were compared to apoptotic lymphocytes from the control group, statistically-significant differences between each mean group were detected (26.4 +/- 1.8 and 12.1 +/- 1.3, respectively), indicating an increased rate of apoptosis in 80.5% of exposed individuals (P < 0.0001, Mann-Whitney U-Test). MTBE and benzene-induced apoptosis is attributed to a discrete block within the cell cycle progression. Because cell cycle analysis showed that in PBL from chemically-exposed individuals, between 20-50% of cells were accumulated at the S-G2/M boundaries. 5. One of the signaling molecules which mediates programmed cell death is nuclear factor Kappa-B (NF-kappa B). NF-kappa B was examined as one of the many molecular mechanisms for mediating cell death by MTBE and benzene. Indeed, addition of inhibitors of NF-kappa B activation pyrrolidine dithiocarbamate (PDTC), to the lymphocytes of the chemically-exposed group was capable of inhibiting programmed cell death by 40%. This reversal of apoptosis almost to the control level by inhibitor of NF-kappa B activation may indicate involvement of this signaling molecule in MTBE and benzene induction of programmed cell death.


Assuntos
Apoptose/efeitos dos fármacos , Benzeno/toxicidade , Carcinógenos/toxicidade , Ciclo Celular/efeitos dos fármacos , Éteres Metílicos/toxicidade , Poluentes da Água/toxicidade , Adolescente , Adulto , Idoso , Biomarcadores , Células Cultivadas , Feminino , Citometria de Fluxo , Humanos , Linfócitos/citologia , Linfócitos/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , NF-kappa B/metabolismo , Tiocarbamatos/toxicidade , Abastecimento de Água/análise
16.
Oncogene ; 14(18): 2201-11, 1997 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-9174056

RESUMO

In this study we describe the presence of high affinity FGF-2 binding sites in the nuclei of U251MG glioma cells (K(d)=7 pM). Immunoprecipitation of total cell extracts with FGF receptor (FGFR) 1-4 antibodies showed that U251MG glioma cells express only FGFR1. [125I]FGF-2 cross linking to nuclear extracts followed by FGFR1 immunoprecipitation showed that FGFR1 may account for the nuclear FGF-2 binding sites. Western blot analysis demonstrated the presence of 103, 118 kDa and small amounts of 145 kDa FGFR1 isoforms in the nuclei of glioma cells. All isoforms contain both the C- and N-terminal domains. Nuclear FGFR1 retains kinase activity. Immunocytochemistry using confocal microscopy showed specific FGFR1 immunoreactivity within the nuclear interior. In continuously proliferating glioma cells, nuclear FGFR1 is constitutively expressed, independent of cell density. In contrast, in nontransformed human astrocytes, nuclear FGFR1 levels fluctuate with the proliferative state of the cell. In quiescent, confluent astrocytes nuclear FGFR1 protein was depleted. An accumulation of nuclear FGFR1 was observed following the transition to a subconfluent, proliferating state. Transfection of a pcDNA3.1-FGFR1 expression vector into glioma cells that do not express FGFR1 resulted in the nuclear accumulation of FGFR1, increased cell proliferation, and stimulated transition from the G0/G1 to the S-phase of the cell cycle. The increased proliferative rate was resistant to inhibition by the cell-impermeable FGF binding antagonist, myoinositol hexakis [dihydrogen phosphate]. Our results suggest that the constitutive nuclear presence of FGFR1 contributes to the increased proliferation of glioma cells while the transient nuclear accumulation of FGFR1 in normal astrocytes may play a role in the transition to a reactive state.


Assuntos
Núcleo Celular/metabolismo , Glioma/metabolismo , Neuroglia/citologia , Neuroglia/metabolismo , Receptores Proteína Tirosina Quinases , Receptores de Fatores de Crescimento de Fibroblastos/metabolismo , Astrócitos/química , Astrócitos/metabolismo , Western Blotting , Divisão Celular/fisiologia , Núcleo Celular/química , Células Cultivadas , Fator 2 de Crescimento de Fibroblastos/metabolismo , Glioma/química , Humanos , Imuno-Histoquímica , Radioisótopos do Iodo , Mitógenos/fisiologia , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos , Receptores Citoplasmáticos e Nucleares/química , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores de Fatores de Crescimento de Fibroblastos/química , Receptores de Fatores de Crescimento de Fibroblastos/imunologia , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Frações Subcelulares , Transfecção
17.
Oncogene ; 14(2): 171-83, 1997 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-9010219

RESUMO

FGF-2 has been implicated in the neoplastic transformation of glioma cells and in the transition of normal quiescent astrocytes to a proliferating, reactive state. In the present study we have observed that in human glial cells, levels and subcellular localization of FGF-2 are different in quiescent and proliferating cells. FGF-2 was detected in the cytoplasm of non-reactive astrocytes in human brain sections. In contrast FGF-2 was located within the cytoplasm and nuclei of reactive astrocytes in gliotic brain tissue and in neoplastic cells of glioma tumors. In vitro, FGF-2 was found predominantly in the nucleus of subconfluent proliferating astrocytes, but was detected only in the cytoplasm of density arrested quiescent astrocytes. Our results suggest that reduced cell contact stimulates nuclear accumulation of FGF-2, accompanying mitotic activation of reactive human astrocytes. FGF-2 was constitutively localized to the nucleus of continuously proliferating glioma cells independent of cell density. A role for intracellular FGF-2 was further suggested by the observation that glioma cells that are not stimulated to proliferate by extracellular FGF-2 proliferated faster when transfected with FGF-2 expressing vectors. This increased proliferation correlated with nuclear accumulation of FGF-2. Cell proliferation was attenuated by 5'-deoxy-5'-methylthioadenosine, a FGF-2 receptor tyrosine kinase inhibitor that acts within the cell, but was unaffected by myo-inositol hexakis [dihydrogen phosphate] that disrupts FGF-2 binding to plasma membrane receptors. Our results indicate that FGF-2 serves as a nuclear regulator of proliferation in astrocytic cells. In glioma cells, the constitutive presence of FGF-2 in the nucleus may promote proliferation that is insensitive to cell contact inhibition.


Assuntos
Astrócitos/citologia , Núcleo Celular/metabolismo , Fator 2 de Crescimento de Fibroblastos/metabolismo , Glioblastoma/patologia , Astrócitos/metabolismo , Comunicação Celular , Contagem de Células , Divisão Celular , Células Cultivadas , Feminino , Glioblastoma/metabolismo , Humanos , Masculino , Neuroglia/citologia , Neuroglia/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos , Receptores de Fatores de Crescimento de Fibroblastos/metabolismo
18.
Mol Biol Cell ; 7(8): 1299-317, 1996 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8856671

RESUMO

In an effort to determine the localization of fibroblast growth factor (FGF) receptors (FGFR) that could mediate the intracellular action of FGF-2, we discovered the presence of high-affinity. FGF-2 binding sites in the nuclei of bovine adrenal medullary cells (BAMC). Western blot analysis demonstrated the presence of 103-, 118-, and 145-kDa forms of FGFR1 in nuclei isolated from BAMC. 125I-FGF-2 cross-linking to nuclear extracts followed by FGFR1 immunoprecipitation showed that FGFR1 can account for the nuclear FGF-2 binding sites. Nuclear FGFR1 has kinase activity and undergoes autophosphorylation. Immunocytochemistry with the use of confocal and electron microscopes demonstrated the presence of FGFR1 within the nuclear interior. Nuclear subfractionation followed by Western blot or immunoelectron microscopic analysis showed that the nuclear FGFR1 is contained in the nuclear matrix and the nucleoplasm. Agents that induce translocation of endogenous FGF-2 to the nucleus (forskolin, carbachol, or angiotensin II) increased the intranuclear accumulation of FGFR1. This accumulation was accompanied by an overall increase in FGF-2-inducible tyrosine kinase activity. Our findings suggest a novel mode for growth factor action whereby growth factor receptors translocate to the nucleus in parallel with their ligand and act as direct mediators of nuclear responses to cell stimulation.


Assuntos
Medula Suprarrenal/metabolismo , Receptores de Fatores de Crescimento de Fibroblastos/metabolismo , Medula Suprarrenal/citologia , Animais , Bovinos , Núcleo Celular/metabolismo , Células Cultivadas , Cinética , Microscopia Imunoeletrônica , Proteínas Tirosina Quinases/metabolismo , Transdução de Sinais , Frações Subcelulares/metabolismo
19.
Brain Res Mol Brain Res ; 38(1): 161-5, 1996 May.
Artigo em Inglês | MEDLINE | ID: mdl-8737680

RESUMO

Fractionation of human astrocytes revealed the presence of 103, 118, and 145 kDa forms of FGF receptor 1 (FGFR1) in isolated nuclei. Only trace amounts of FGFR1 proteins were detected in the cell membrane or cytoplasmic fractions. Nuclear FGFR1 is found in the nucleoplasm and nuclear matrix but not in chromatin. Immuno-confocal microscopy further demonstrates the intranuclear presence of FGFR1 and its colocalization with FGF-2. Nuclear FGFR1 binds to FGF-2 and has tyrosine kinase activity. Translocation of functional growth factor receptors into the cell nucleus offers a novel mechanism for growth factor action.


Assuntos
Astrócitos/química , Núcleo Celular/química , Fator 1 de Crescimento de Fibroblastos , Receptores de Fatores de Crescimento de Fibroblastos/análise , Membrana Celular/química , Células Cultivadas , Citoplasma/química , Humanos , Peso Molecular
20.
Oncogene ; 12(4): 827-37, 1996 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-8632905

RESUMO

The design, chemical synthesis and biological activities of a nuclease-resistant, nontoxic bioactive 2-5A derivative, AA-etherA [i.e., adenylyl-(2'-5')-adenylyl-(2'-2")-9-[(2'-hydroxyethoxy)-methyl]adenine], are described as a new approach to the inhibition of breast cancer cell growth. AA-etherA inhibits DNA replication and cell division of both estrogen receptor positive (MCF-7) and estrogen receptor negative (BT-20) breast cancer cells in culture in a dose-dependent manner. Maximal inhibition in MCF-7 and BT-20 cells was obtained with 100 microM AA-etherA after four days of treatment, with an GI50 of 58 and 37 microM, respectively. AA-etherA is stable in the cytoplasm. Treated cells accumulate within the late G1/early S phase of the cell cycle and then progress only very slowly through S phase. AA-etherA does not activate RNase L, as do 2-5A and other 2-5A derivatives, nor does it increase p68 kinase (PKR) content of the cells. High resolution, two-dimensional protein gel electrophoresis reveals twofold or greater inhibition of synthesis of 92 proteins out of 682 proteins that were reproducibly detected as high quality spots with average rates of synthesis of > or = 20 p.p.m. in untreated cells. The specificity of the effects of AA-etherA on select proteins and its failure to activate RNase L indicate that AA-etherA does not act through a general effect on mRNA translation or stability, but rather inhibits cell proliferation through a block to DNA replication, with a concommitant reduction in the synthesis of specific proteins, some of which may be required for cell cycle transit. Two likely targets to account for the AA-etherA inhibition of DNA replication are DNA topoisomerase I, which is inhibited by AA-etherA in other cell lines, and thymidine kinase, which could be inhibited in a manner similar to the effect of acyclovir. These data indicate that 2-5A analogs, particularly bifunctional 2-5A analogs like AA-etherA, will be useful for controlling cancer cell growth. Further development of such 2-5A analogs may provide highly specific compounds for chemotherapy and chemoprevention.


Assuntos
Nucleotídeos de Adenina/farmacologia , Antineoplásicos/farmacologia , Divisão Celular/efeitos dos fármacos , Replicação do DNA/efeitos dos fármacos , Oligorribonucleotídeos/farmacologia , Receptores de Estrogênio/análise , Nucleotídeos de Adenina/síntese química , Nucleotídeos de Adenina/química , Antineoplásicos/síntese química , Antineoplásicos/química , Neoplasias da Mama , Linhagem Celular , DNA Topoisomerases Tipo I/metabolismo , Relação Dose-Resposta a Droga , Endorribonucleases/metabolismo , Feminino , Citometria de Fluxo , Humanos , Indicadores e Reagentes , Cinética , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Inibidores da Síntese de Proteínas/farmacologia , Fatores de Tempo , Células Tumorais Cultivadas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...