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1.
Eur J Neurol ; 20(3): 527-533, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23145482

RESUMO

BACKGROUND AND PURPOSE: Nocebo refers to adverse events (AEs) generated by patient's negative expectations that medical treatment will likely harm instead of heal and can be assessed in placebo-controlled randomized controlled trials (RCTs). We examined AEs following placebo administration in RCTs for Parkinson's disease (PD). METHODS: After a systematic Medline search for RCTs for PD pharmacologic treatments published between 2000 and 2010, we assessed percentages of placebo-treated patients reporting at least one AE or discontinuing due to placebo intolerance and searched for factors influencing nocebo's extent. RESULTS: Data were extracted from 41 RCTs fulfilling search criteria. Of 3544 placebo-treated patients, 64.7% (95% CI: 53.6-74.4) reported at least one AE and 8.8% (95% CI: 6.8-11.5) discontinued placebo treatment due to intolerance. The number of AEs per 100 person-months was 25.9 (95% CI: 16.8-39.8). Nocebo dropout rate was positively related to study population size and year of publication. Increased number of AEs per 100 person-months was negatively correlated with the duration of treatment. AE rates, dropout rates, and AEs per 100 person-months in placebo- and active drug-treated patients were strongly correlated (r = 0.941, 0.695, and 0.824, respectively). CONCLUSIONS: Our analysis indicates a significant dropout rate related to nocebo in trials for PD treatment. Adherence and efficacy may be adversely affected with additional implications for clinical practice.


Assuntos
Doença de Parkinson/tratamento farmacológico , Efeito Placebo , Ensaios Clínicos Controlados Aleatórios como Assunto/psicologia , Humanos
3.
Mov Disord ; 26(2): 264-70, 2011 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-21412833

RESUMO

The efficacy and safety of levetiracetam (LEV), administered for management of levodopa-induced dyskinesias (LID) in Parkinson's disease (PD), was examined using a multicenter, double-blind, placebo-controlled, parallel groups, crossover trial. Because of having a period effect, data after crossover point was excluded from analysis. Levodopa-treated PD participants with LID (n = 38) received LEV 500 mg/day, were assessed, titrated to 1,000 mg/day and reassessed, before and after crossover. The placebo group followed the same routine. Primary efficacy was defined from percent change in "On with LID" time from patient diaries. Secondary efficacy assessment used "On without LID," "Off" time, unified PD rating scale (UPDRS), clinical global impression (CGI), and Goetz dyskinesia scale after levodopa challenge. Safety measures were also performed. On with LID time decreased 37 minutes (95% confidence interval [CI] 0.59, 7.15; P = 0.02) at 500 mg/day, 7.85% 75 minutes (95% CI 3.3, 12.4; P = 0.002) at 1,000 mg/day. On without LID time increased by 46 minutes (95% CI -1.55, -0.03; P = 0.04) at 500 mg/day and 55 minutes (95% CI -10.39, -1.14; P = 0.018) at 1,000 mg/day. UPDRS 32 showed decreased dyskinesia duration mean change 0.35 (95% CI 0.09, 0.5; P = 0.009) at 1,000 mg/day. CGI showed LID decreased by 0.7 (95% CI 0.21, 1.18; P = 0.006) at 1,000 mg/day. Patient diaries and UPDRS show no increase in Off time. This exploratory trial provides evidence that LEV in 1,000 mg/day, slowly titrated, could be useful in improving LID as was assessed with patient diaries, UPDRS, and CGI scales, safely, with minimal side effects.


Assuntos
Antiparkinsonianos/efeitos adversos , Discinesia Induzida por Medicamentos/tratamento farmacológico , Levodopa/efeitos adversos , Doença de Parkinson/tratamento farmacológico , Piracetam/análogos & derivados , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Cross-Over , Método Duplo-Cego , Discinesia Induzida por Medicamentos/fisiopatologia , Feminino , Humanos , Levetiracetam , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/fisiopatologia , Piracetam/efeitos adversos , Piracetam/uso terapêutico , Resultado do Tratamento
4.
Acta Neurol Scand ; 122(1): 9-14, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20028344

RESUMO

OBJECTIVES: To examine whether ideomotor apraxia exists in patients with subcortical ischemic lesions. PATIENTS AND METHODS: A matched-control, prospective and multi-centered research design was used. Ideomotor apraxia, anxiety and depression were assessed by the Movement Imitation Test and the Hamilton scales, respectively. RESULTS: Forty two consecutive patients with subcortical ischemic stroke and an equal number of healthy participants, matched in age and sex were included. Paired-sample t-tests showed that patients had significantly more apractic elements in their movements (t = 5.03, P < 0.01), higher anxiety (t = -2.55, P = 0.0014) and depression levels (t = -2.61, P = 0.012) than their healthy matched participants. Participants with higher anxiety and depression scores performed worse on the Movement Imitation Test. CONCLUSIONS: Ischemic damage of subcortical modular systems may affect praxis.


Assuntos
Apraxia Ideomotora/diagnóstico , Apraxia Ideomotora/etiologia , Infarto Cerebral/complicações , Ansiedade/diagnóstico , Ansiedade/etiologia , Infarto Cerebral/psicologia , Depressão/diagnóstico , Depressão/etiologia , Feminino , Humanos , Masculino , Análise por Pareamento , Testes Neuropsicológicos
5.
Acta Neurochir Suppl ; 97(Pt 2): 163-70, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17691301

RESUMO

Deep brain stimulation (DBS) represents one of the more recent advancements in Neurosurgery. Even though its most successful applications evolved in movement disorders (MDs), indications now include pain, psychiatric disorders, epilepsy, cluster headaches and Tourette syndrome. As this type of surgery gains popularity and the indications for DBS surgery increase, so it will certainly increase the number of neurosurgeons who will use this neuromodulatory technique. A detailed description of the technical aspects of the DBS procedure, as it is performed in our department, is presented. In our opinion, our method is a good combination of all the well-established necessary techniques in a cost-effective way. This technical article may be helpful to neurosurgeons considering to start performing this type of surgery. It could also prompt others who perform DBS regularly to express their views, and hence, lead to further refinement of this demanding procedure.


Assuntos
Estimulação Encefálica Profunda/instrumentação , Estimulação Encefálica Profunda/métodos , Transtornos dos Movimentos/cirurgia , Eletrodos , Humanos , Imageamento por Ressonância Magnética , Transtornos dos Movimentos/patologia , Procedimentos Neurocirúrgicos , Cirurgia Assistida por Computador
6.
Acta Neurochir Suppl ; 97(Pt 2): 575-86, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17691350

RESUMO

The basal ganglia are best known for their role in motor planning and execution. However, it is currently widely accepted that they are also involved in cognitive and emotional behaviors. Parts of the basal ganglia play a key role in reward and reinforcement, addictive behaviors and habit formation. Pathophysiological processes underlying psychiatric disorders such as depression, obsessive compulsive disorder and even schizophrenia involve the basal ganglia and their connections to many other structures and particularly to the prefrontal cortex and the limbic system. In this article, we aim, on the basis of current research, to describe in a succinct manner the most important connections of the basal ganglia with the limbic system which are relevant to normal behaviors but also to psychiatric disorders. Currently, we possess sufficiently powerful tools that enable us to modulate brain networks such as cortex stimulation (CS) or deep brain stimulation (DBS). Notably, neuromodulation of basal ganglia function for the treatment of movement disorders has become a standard practice, which provides insights into the psychiatric problems that occur in patients with movement disorders. It is clear that a sound understanding of the currently available knowledge on the circuits connecting the basal ganglia with the limbic system will provide the theoretical platform that will allow precise, selective and beneficial neuromodulatory interventions for refractory psychiatric disorders.


Assuntos
Gânglios da Base/anatomia & histologia , Gânglios da Base/fisiologia , Sistema Límbico/anatomia & histologia , Sistema Límbico/fisiologia , Vias Neurais/anatomia & histologia , Animais , Ansiedade/patologia , Ansiedade/terapia , Estimulação Encefálica Profunda/métodos , Humanos , Transtornos do Humor/patologia , Transtornos do Humor/terapia
7.
Muscle Nerve ; 23(12): 1856-61, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11102909

RESUMO

Hypertrophic cardiomyopathy (HCM) is due to a number of mutations of contractile protein genes such as beta-cardiac myosin, myosin binding protein-C, and troponin-T. Unlike troponin-T, beta-myosin is a constituent of slow skeletal muscle and its mutations generally have a better prognosis. In order to investigate the usefulness of electromyography in detecting skeletal muscle involvement in HCM, 46 patients were examined using both conventional electromyography (EMG) and quantitative electromyography (QEMG) methods. The QEMG involved motor unit potential (MUP) analysis, turns/amplitude (TAA) analysis, and power spectrum analysis of the interference pattern. Using conventional EMG, myopathic findings were demonstrated in 13 patients (28%). Receiver operating characteristic (ROC) analysis of the results of a discriminant function extracted using QEMG values, identified correctly 10 out of 11 normal controls and all 9 myopathic control patients, and displayed a 15% presence of myopathy (7 patients) among the cardiomyopathy group. The duration of MUPs was the most sensitive among the quantitative parameters in differentiating normal from myopathic subjects. Since skeletal muscle involvement may be due to distinct gene mutations, normal and myopathic EMG findings may reflect HCM subpopulations with a different genetic substrate.


Assuntos
Cardiomiopatia Hipertrófica/fisiopatologia , Eletromiografia/métodos , Músculo Esquelético/fisiopatologia , Doenças Musculares/diagnóstico , Adolescente , Adulto , Idoso , Potencial Evocado Motor , Reações Falso-Positivas , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Musculares/complicações , Doenças Musculares/fisiopatologia , Reprodutibilidade dos Testes
8.
Eur Neuropsychopharmacol ; 10(5): 315-24, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10974601

RESUMO

The serotonergic activity in hippocampus was investigated following acute and chronic treatment with the antipsychotic drugs haloperidol and risperidone. Acute administration of risperidone, the serotonin(2) (5-HT(2)) receptor antagonist ketanserin, and the dopamine (DA)-D(2) receptor antagonist raclopride increased the 5-hydroxyindoleacetic acid/serotonin (5-HIAA/5-HT) ratio. In contrast, acute administration of haloperidol did not affect this ratio. Chronic administration of risperidone maintained the increased 5-HIAA/5-HT ratio; a challenge dose of risperidone after the chronic treatment and the subsequent washout period also maintained the increased ratio. Chronic administration of haloperidol as well as a challenge dose of haloperidol following chronic treatment did not affect the serotonergic activity in hippocampus. Administration of ketanserin or raclopride after chronic treatment and the washout period induced an additional increase in the 5-HIAA/5-HT ratio in risperidone-treated rats. Moreover, a challenge dose of ketanserin, but not raclopride, increased the 5-HIAA/5-HT ratio in haloperidol-treated rats. The present results indicate that acute and chronic treatment of haloperidol or risperidone modified serotonergic activity in the hippocampus in a different way. Moreover, the augmentation of serotonergic activity induced by risperidone did not seem to be solely related to dopaminergic or serotonergic properties and may be of particular relevance for the amelioration of schizophrenia symptoms.


Assuntos
Antipsicóticos/farmacologia , Haloperidol/farmacologia , Hipocampo/metabolismo , Ketanserina/farmacologia , Racloprida/farmacologia , Serotonina/metabolismo , Animais , Antagonistas dos Receptores de Dopamina D2 , Hipocampo/efeitos dos fármacos , Ácido Hidroxi-Indolacético/metabolismo , Masculino , Ratos , Ratos Wistar , Risperidona/farmacologia
9.
Psychopharmacology (Berl) ; 127(3): 181-6, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8912395

RESUMO

The acute and chronic administration effects of risperidone (Ris), a mixed 5HT2/D2 receptor antagonist, versus haloperidol (Hal) on dopaminergic and serotoninergic activity were investigated in the rat prefrontal cortex (Pfc), and the whole striatum (Str) as well as separately, in dorsal striatum (StrD) and nucleus accumbens (Acb). During acute administration, Hal was found to be more potent than Ris in increasing DA turnover rate in StrD. In contrast, during chronic administration, Ris but not Hal, continued to increase DA turnover activity in StrD. Moreover, in contrast to Hal, chronic Ris treatment continued to increase DA and 5-HT turnover rate in Pfc. These differential effects reveal that Hal does not share common characteristics with Ris with respect to its neurochemical profile in the Str and Pfc.


Assuntos
Antipsicóticos/administração & dosagem , Encéfalo/efeitos dos fármacos , Dopamina/metabolismo , Haloperidol/administração & dosagem , Risperidona/administração & dosagem , Serotonina/metabolismo , Animais , Encéfalo/metabolismo , Masculino , Ratos , Ratos Wistar , Fatores de Tempo
10.
Biochem Biophys Res Commun ; 202(3): 1705-9, 1994 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-8060360

RESUMO

Heparin-binding EGF-like growth factor (HB-EGF) is a polypeptide with an apparent molecular weight of 22 kilodalton that is related to epidermal growth factor (EGF) and that binds and activates the EGF receptor. We examined HB-EGF biological action and expression in human pancreatic cancer cell lines, and compared HB-EGF expression in normal and cancerous pancreatic tissues. HB-EGF enhanced the growth of human pancreatic cancer cells in a dose-dependent manner. Several cell lines expressed HB-EGF mRNA transcripts, and the transcript level was enhanced by HB-EGF, as well as by 12-O-tetradecanoylphorbol-13-acetate and transforming growth factor-alpha (TGF-alpha). By comparison with the normal pancreas, HB-EGF mRNA levels were increased in human pancreatic cancer tissues. These findings suggest that HB-EGF may participate in aberrant autocrine and paracrine activation of the EGF receptor, thereby contributing to pancreatic cancer cell growth.


Assuntos
Fator de Crescimento Epidérmico/biossíntese , Neoplasias Pancreáticas/metabolismo , Northern Blotting , Fator de Crescimento Epidérmico/genética , Fator de Crescimento Epidérmico/metabolismo , Heparina/metabolismo , Fator de Crescimento Semelhante a EGF de Ligação à Heparina , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , RNA Mensageiro/metabolismo , Acetato de Tetradecanoilforbol/farmacologia , Células Tumorais Cultivadas
11.
Endocrinology ; 132(6): 2279-86, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8504731

RESUMO

In studies to determine whether Saccharomyces cerevisiae produced estrogens, the organism was grown in culture media prepared using distilled water autoclaved in polycarbonate flasks. The yeast-conditioned media showed the presence of a substance that competed with [3H]estradiol for binding to estrogen receptors (ER) from rat uterus. However, it soon became clear that the estrogenic substance in the conditioned media was not a product of the yeast grown in culture, but was leached out of the polycarbonate flasks during the autoclaving procedure. [3H]Estradiol displacement activity was monitored by ER RRA, and the active substance was purified from autoclaved medium using a series of HPLC steps. The final purified product was identified as bisphenol-A (BPA) by nuclear magnetic resonance spectroscopy and mass spectrometry. BPA could also be identified in distilled water autoclaved in polycarbonate flasks without the requirement of either the organism or the constituents of the culture medium. Authentic BPA was active in competitive RRAs, demonstrating an affinity approximately 1:2000 that of estradiol for ER. In functional assays, BPA (10-25 nM) induced progesterone receptors in cultured human mammary cancer cells (MCF-7) at a potency of approximately 1:5000 compared to that of estradiol. The BPA effect on PR induction was blocked by tamoxifen. In addition, BPA (25 nM) increased the rate of proliferation of MCF-7 cells assessed by [3H]thymidine incorporation. Thus, BPA exhibited estrogenic activity by both RRA and two functional bioresponse assays. Finally, MCF-7 cells grown in media prepared with water autoclaved in polycarbonate exhibited higher progesterone receptor levels than cells.grown in media prepared with water autoclaved in glass, suggesting an estrogenic effect of the water autoclaved in polycarbonate. Our findings raise the possibility that unsuspected estrogenic activity in the form of BPA may have an impact on experiments employing media autoclaved in polycarbonate flasks. It remains to be determined whether BPA derived from consumer products manufactured from polycarbonate could significantly contribute to the pool of estrogenic substances in the environment.


Assuntos
Estrogênios/farmacologia , Fenóis/farmacologia , Cimento de Policarboxilato , Esterilização/métodos , Animais , Compostos Benzidrílicos , Cromatografia Líquida de Alta Pressão , Meios de Cultura , Equipamentos e Provisões , Estrogênios/metabolismo , Feminino , Humanos , Laboratórios , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Fenóis/análise , Fenóis/química , Cimento de Policarboxilato/química , Receptores de Estrogênio/metabolismo , Receptores de Estrogênio/fisiologia , Receptores de Progesterona/metabolismo , Saccharomyces cerevisiae/metabolismo , Células Tumorais Cultivadas , Útero/metabolismo , Água/química , Água/farmacologia
12.
J Biol Chem ; 264(19): 11186-92, 1989 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-2738064

RESUMO

It has been shown by us and others that progesterone inhibits the growth of Trichophyton mentagrophytes and that the organism escapes from this inhibition over time. We report here studies which show that escape from growth inhibition is related to the enzymatic transformation of progesterone to polar metabolites. Isolation and identification of the progesterone metabolites confirm the production of 15 alpha-hydroxyprogesterone. In addition, three other metabolites were isolated. Two of these were determined to be 1-dehydroprogesterone and 11 alpha-hydroxyprogesterone. The third metabolite was a 1-dehydro-hydroxyprogesterone, but the location of the hydroxyl group could not be determined unequivocally. Studies using authentic 15 alpha-hydroxyprogesterone, 1-dehydroprogesterone, and 11 alpha-hydroxyprogesterone reveal that these derivatives are significantly less inhibitory to the growth of T. mentagrophytes than progesterone. Pretreatment of organisms with progesterone augments the rate of metabolism and enhances escape. We have described previously a progesterone-binding protein (PBP) in cytoplasmic extracts of T. mentagrophytes and hypothesized that progesterone mediates growth inhibition by binding to the PBP of this organism. The relative binding affinity that progesterone and its metabolites display for PBP correlates with the relative growth inhibitory potency of these compounds. These results suggest that metabolism of progesterone to more polar and less inhibitory compounds, which exhibit lower affinity for PBP, is the mechanism of escape from progesterone-mediated inhibition of growth in this organism.


Assuntos
Progesterona/metabolismo , Trichophyton/crescimento & desenvolvimento , Ligação Competitiva , Cromatografia Líquida de Alta Pressão , Hidroxiprogesteronas/metabolismo , Hidroxiprogesteronas/farmacologia , Cinética , Espectrometria de Massas , Progesterona/análogos & derivados , Progesterona/farmacologia , Globulina de Ligação a Progesterona/metabolismo , Trichophyton/efeitos dos fármacos , Trichophyton/metabolismo
13.
Endocrinology ; 119(3): 1362-9, 1986 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3525131

RESUMO

We have previously shown the presence of 17 beta-estradiol in extracts of commercially prepared Saccharomyces cerevisiae ss well as the production of estradiol by yeast grown in the laboratory. In our current study, yeast grown in a chemically defined medium synthesized estradiol in only small amounts, (less than 500 pg/liter). We have analyzed a variety of media commonly used for growing yeast and found that substantial estradiol production (greater than 5 ng/liter) was obtained when yeast were grown in medium supplemented with Bacto-peptone. The peptone was shown to contain significant amounts of estrone, and the results of the experiments establish a precursor-product relationship where estrone from the medium is metabolized to estradiol by S. cerevisiae. Studies with added [3H]estrone demonstrated rapid conversion into [3H]estradiol and a 3H-labeled nonpolar estrogen derivative. The commercially obtained yeast used previously had been grown in a molasses medium. We demonstrate here that the molasses medium contains substantial amounts of estrone and estradiol. We conclude that the conversion of estrone in a culture medium to estradiol in laboratory grown yeast and estrone and estradiol present in the commercially grown yeast medium account for the majority of estradiol found in yeast.


Assuntos
Estrogênios/metabolismo , Saccharomyces cerevisiae/metabolismo , Cromatografia Líquida de Alta Pressão , Meios de Cultura , Estradiol/análise , Estrona/análise , Melaço , Peptonas , Radioimunoensaio , Fatores de Tempo
14.
Proc Natl Acad Sci U S A ; 81(15): 4722-6, 1984 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-6379650

RESUMO

Saccharomyces cerevisiae possesses a high-affinity estrogen binding protein and an endogenous ligand that displaces [3H]estradiol from both the yeast binding protein and mammalian estrogen receptors. Semipurified preparations of this ligand have been shown to exhibit estrogenic activity in mammalian systems. We now describe the purification procedure and ultimate identification of the estrogenic substance in extracts of S. cerevisiae as 17 beta-estradiol. Organic solvent extracts of commercially obtained dried yeast were sequentially chromatographed on silica gel columns and then subjected to a series of reversed phase HPLC fractionations. Active ligand was monitored by [3H]estradiol displacement in a rat uterine cytosol assay. After seven chromatography steps, the purified and highly active ligand exhibited a single peak with retention times identical to those of 17 beta-estradiol on both HPLC and GC. The yeast material was identified as 17 beta-estradiol by its UV absorbance and mass spectrometric fragmentation pattern. In addition, radioimmunoassay confirmed the presence of approximately the same mass of 17 beta-estradiol (approximately equal to 800 ng/1.5 kg of yeast) as estimated both by a competitive binding assay with estrogen receptor and by mass spectrometry. Extraneous contamination by estradiol was excluded by repeat experiments with different batches of starting material and demonstration of estradiol by RIA in conditioned medium and cell pellets of laboratory-grown S. cerevisiae whereas non-conditioned medium did not possess the steroid. We conclude that 17 beta-estradiol is a yeast product.


Assuntos
Estradiol/isolamento & purificação , Saccharomyces cerevisiae/análise , Estradiol/imunologia , Radioimunoensaio
15.
Science ; 224(4653): 1109-11, 1984 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-6372097

RESUMO

Partially purified lipid extracts of Saccharomyces cerevisiae contain a substance that displaces tritiated estradiol from rat uterine cytosol estrogen receptors. The yeast product induces estrogenic bioresponses in mammalian systems as measured by induction of progesterone receptors in cultured MCF-7 human breast cancer cells and by a uterotrophic response and progesterone receptor induction after administration to ovariectomized mice. The findings raise the possibility that bakers' yeast may be a source of environmental estrogens.


Assuntos
Estrogênios/biossíntese , Saccharomyces cerevisiae/metabolismo , Animais , Bioensaio , Neoplasias da Mama/metabolismo , Estradiol/metabolismo , Estrogênios/farmacologia , Feminino , Humanos , Camundongos , Receptores de Progesterona/metabolismo , Útero/efeitos dos fármacos
16.
J Biol Chem ; 259(6): 3450-6, 1984 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-6368545

RESUMO

This paper further characterizes the estrogen-binding protein we have described in the cytosol of the yeast Saccharomyces cerevisiae. [3H]Estradiol was used as the radioprobe, and specific binding of cytosol fractions was measured by chromatography on Sephadex minicolumns. Other 3H-steroids did not exhibit specific binding. [3H]Estradiol binding was destroyed by treatment with trypsin, but not RNase, DNase, or phospholipase; N-ethylmaleimide substantially decreased the binding. The yeast did not metabolize estradiol added to the medium, and extraction and chromatography of the bound moiety showed it to be unmetabolized estradiol. Scatchard analysis of cytosol from both a and alpha mating types as well as the a/alpha diploid cell revealed similar binding properties: an apparent dissociation constant or Kd(25 degrees) for [3H]estradiol of 1.6-1.8 nM and a maximal binding capacity or Nmax of approximately 2000-2800 fmol/mg of cytosol protein. Gel exclusion chromatography on Sephacryl S-200 and high performance liquid chromatography suggested a Stokes radius of approximately 30 A. Sucrose gradient centrifugation showed a sedimentation coefficient of approximately 5 S, and the complex did not exhibit ionic dependent aggregation. The estrogen binder in S. cerevisiae differed in its steroidal specificities from classical mammalian estrogen receptors in rat uterus. 17 beta-Estradiol was the best competitor, 17 alpha-estradiol had about 5% the activity, and diethylstilbestrol exhibited negligible binding affinity as did tamoxifen, nafoxidine, and the zearalenones. In summary, a high affinity, stereospecific, steroid-selective binding protein has been demonstrated in the cytosol of the simple yeast S. cerevisiae. We speculate that this molecule may represent a primitive hormone receptor system, possibly for an estrogen-like message molecule.


Assuntos
Estradiol/metabolismo , Receptores de Estrogênio/metabolismo , Saccharomyces cerevisiae/metabolismo , Citosol/metabolismo , Estabilidade de Medicamentos , Cinética , Peso Molecular , Receptores de Estrogênio/isolamento & purificação
17.
Science ; 218(4569): 297-8, 1982 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-6289434

RESUMO

A protein macromolecule in the cytosol of the unicellular eukaryotic yeast Saccharomyces cerevisiae selectively binds the vertebrate estrogen hormone 17 beta-estradiol with high affinity. Lipid extracts of the yeast cells or the conditioned growth medium yield a substance that can bind competitively to the tritiated estradiol-binding sites in the yeast and to mammalian estrogen receptors. These findings suggest that the binding protein may be a primitive hormone receptor and that the lipid-extractable substance represents the endogenous ligand.


Assuntos
Receptores de Estrogênio/análise , Saccharomyces cerevisiae/metabolismo , Animais , Ligação Competitiva , Cromatografia Líquida de Alta Pressão , Citosol/metabolismo , Feminino , Ligantes , Ratos , Receptores de Superfície Celular/metabolismo
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