Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 158
Filtrar
1.
Urologe A ; 55(12): 1595-1600, 2016 Dec.
Artigo em Alemão | MEDLINE | ID: mdl-27352272

RESUMO

BACKGROUND: Pelvic organ prolapse is a common medical finding. The use of perineal ultrasound for diagnosis of cystoceles is gaining in importance. OBJECTIVES: The purpose of this work was to test whether perineal ultrasound can be used to diagnose a cystocele before surgery and for follow-up examination. Furthermore, patient satisfaction during speculum examination and perineal ultrasound was compared. MATERIALS AND METHODS: 33 women with cystocele were examined before and after anterior colporrhaphy. Symptoms and satisfaction were documented with questionnaires. RESULTS: Ultrasound measurements of both examiners were correlated before and after colporrhaphy. Also, the degree of cystocele and ultrasound were correlated during Valsalva after surgery. There was no clear relation between typical symptoms of the cystocele and ultrasound measurements. The patient's comfort is higher during ultrasound than during speculum examination (r = 0.45; p = 0.04. t = 4,418; p < 0.01). CONCLUSION: The results of the perineal ultrasound are reproducible before and after colporrhaphy. Patients prefer ultrasound to the speculum examination. A sonographic scale of the cystocele would extend the use of perineal ultrasound.


Assuntos
Cistocele/diagnóstico por imagem , Cistocele/psicologia , Conforto do Paciente , Satisfação do Paciente , Períneo/diagnóstico por imagem , Ultrassonografia/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Alemanha , Humanos , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
2.
Colorectal Dis ; 12(5): 448-51, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-19320666

RESUMO

INTRODUCTION: Sacral nerve stimulation (SNS) is a treatment for consecutive therapy resistant faecal incontinence or constipation. Little is known about the effects of SNS on uterocervical function. Therefore, it is advised to turn off the stimulator during pregnancy or to wait with permanent implantation of the stimulator until family completion. Diagnostic ultrasound provides an, non-invasive, opportunity to study various aspects of uterine activity. The purpose of this pilot study was to assess the influence of SNS on endometrial waves of the nonpregnant uterus by ultrasound recordings. METHOD: Six patients with an implanted SNS were included. Ultrasound recordings were performed with the stimulator turned off and in three stimulation frequencies. Uterine activity is described as wave frequency and wave direction. RESULTS: All three premenopausal patients showed endometrial activity with the stimulator turned off. This activity was maintained with the stimulator turned on in two patients, but disappeared in one patient. All three postmenopausal patients had no endometrial activity with the stimulator turned off. In one patient there was activity with the stimulator turned on at a frequency of 21 Hz. CONCLUSION: We have shown some effect of SNS on uterine activity. In premenopausal women we discovered that SNS seems to exhibit no effect or an inhibitory effect rather than an excitatory effect on uterine activity. Based on the preliminary results of this study, we can not recommend any guidelines for SNS usage during conception and pregnancy. A larger study in premenopausal women with SNS is needed to investigate the significance of these changes.


Assuntos
Constipação Intestinal/terapia , Terapia por Estimulação Elétrica/métodos , Endométrio/fisiopatologia , Incontinência Fecal/terapia , Adulto , Endométrio/diagnóstico por imagem , Feminino , Humanos , Plexo Lombossacral/fisiopatologia , Pessoa de Meia-Idade , Diafragma da Pelve/inervação , Projetos Piloto , Próteses e Implantes , Sacro , Ultrassonografia
3.
Langmuir ; 25(12): 6800-7, 2009 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-19441781

RESUMO

Solvation is an important phenomenon, especially in association with heterogeneous phase interactions. Coumarin C522, C(14)H(12)NO(2)F(3), is used as a fluorophore probe to study the interaction between coumarin and a reduced-charge montmorillonite (RCM) surface. Such hydrophilic and hydrophobic interactions are of interest for sorption processes in confined environments. The prepared RCM series with 0.00, 0.12, 0.26, 0.43, 0.66, and 0.97 Li(+) molar fractions provide different surface charges. The aqueous dispersion of the C522/water/RCM system is studied by using steady-state and time-resolved fluorescence spectroscopies. Both the Stokes shift and the dynamics of the solvation process varied as a function of surface charge. Steady-state fluorescence spectroscopy reveals that the C522 Stokes shift varies from 5,115 cm(-1) for the 0.00 Li(+) molar fraction to 3,988 cm(-1) for the 0.97 Li(+) molar fraction. Time-resolved fluorescence spectroscopy determines that the decay time T((1)) varies from 1.0 ps for the 0.00 Li(+) molar fraction to 3.6 ps for the 0.97 Li(+) molar fraction. Within the range of a few picoseconds, the dynamics of the water solvation shell may be described with H-bond rearrangement, modified with the different RCM surface charges. Two models illustrating the interactions between C522 and RCM in water are proposed which qualitatively describe the dynamics. To the best of our knowledge, this experiment is the first measurement of solvation dynamics on a montmorillonite structure surface using ultrafast laser fluorescence spectroscopy.


Assuntos
Bentonita/química , Cumarínicos/química , Solubilidade , Espectrometria de Fluorescência , Água/química
4.
Bioinorg Chem Appl ; : 151-68, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-18365050

RESUMO

Recent developments in the understanding of the molecular control of iron homeostasis provided novel insights into the mechanisms responsible for normal iron balance. However in chronic anemias associated with iron overload, such mechanisms are no longer sufficient to offer protection from iron toxicity, and iron chelating therapy is the only method available for preventing early death caused mainly by myocardial and hepatic damage. Today, long-term deferoxamine (DFO) therapy is an integral part of the management of thalassemia and other transfusion-dependent anemias, with a major impact on well-being and survival. However, the high cost and rigorous requirements of DFO therapy, and the significant toxicity of deferiprone underline the need for the continued development of new and improved orally effective iron chelators. Within recent years more than one thousand candidate compounds have been screened in animal models. The most outstanding of these compounds include deferiprone (L1); pyridoxal isonicotinoyl hydrazone (PIH) and; bishydroxy- phenyl thiazole. Deferiprone has been used extensively as a substitute for DFO in clinical trials involving hundreds of patients. However, L1 treatment alone fails to achieve a negative iron balance in a substantial proportion of subjects. Deferiprone is less effective than DFO and its potential hepatotoxicity is an issue of current controversy. A new orally effective iron chelator should not necessarily be regarded as one displacing the presently accepted and highly effective parenteral drug DFO. Rather, it could be employed to extend the scope of iron chelating strategies in a manner analogous with the combined use of medications in the management of other conditions such as hypertension or diabetes. Coadministration or alternating use of DFO and a suitable oral chelator may allow a decrease in dosage of both drugs and improve compliance by decreasing the demand on tedious parenteral drug administration. Combined use of DFO and L1 has already been shown to result in successful depletion of iron stores in patients previously failing to respond to single drug therapy, and to lead to improved compliance with treatment. It may also result in a "shuttle effect" between weak intracellular chelators and powerful extracellular chelators or exploit the entero-hepatic cycle to promote fecal iron excretion. All of these innovative ways of chelator usage are now awaiting evaluation in experimental models and in the clinical setting.

5.
J Lab Clin Med ; 139(1): 50-8, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11873245

RESUMO

Although the beneficial effects of deferoxamine (DFO) on iron-associated morbidity and mortality are well documented, the role of deferiprone (L1) in the management of transfusional iron overload is controversial. This debate involves not only the question of efficacy but also of safety, with particular emphasis on the risk of a paradoxical aggravation of iron toxicity by L1. We used the iron-loaded gerbil model introduced by Carthew et al to compare the chelating efficacy of L1, DFO, or both in two gerbil strains treated by means of weekly iron-dextran injections: Psammomys obesus and pathogen-free Mongolian gerbils (Meriones unguiculatus). The difference between the high mortality and advanced hepatocellular necrosis observed in iron-loaded P obesus and the absence of mortality and limited morbidity encountered in pathogen-free Mongolian gerbils is most likely explained by the prevention of coincidental laboratory infections in the latter group. Iron-chelating treatment in all experimental groups resulted in a significant decrease in hepatic iron concentrations and normalization of mitochondrial respiratory enzyme activities, with combined L1 and DFO treatment being the most efficient, followed, in decreasing order, by DFO and L1 as single-drug treatments. Judged by tissue iron concentrations, mitochondrial enzyme activity, and hepatic histology, we could find no evidence of a paradoxical aggravation of iron toxicity by L1 in either of the two series of studies. Although these data appear to be reassuring, the present controversy related to the role of L1 in the development of hepatic cirrhosis should be eventually settled by clinical studies evaluating the effects of long-term iron-chelating treatment.


Assuntos
Desferroxamina/uso terapêutico , Modelos Animais de Doenças , Quelantes de Ferro/uso terapêutico , Sobrecarga de Ferro/tratamento farmacológico , Piridonas/uso terapêutico , Animais , Deferiprona , Feminino , Gerbillinae , Sobrecarga de Ferro/metabolismo , Sobrecarga de Ferro/patologia , Fígado/patologia , Miocárdio/patologia
6.
Plant Physiol ; 127(3): 1044-52, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11706185

RESUMO

Previous studies using purified RNA polymerase from mustard (Sinapis alba) chloroplasts showed control of transcription by an associated protein kinase. This kinase was found to respond to reversible thiol/disulfide formation mediated by glutathione (GSH), although at concentrations exceeding those thought to exist in vivo. In the present study, several lines of evidence are presented to substantiate the functioning of this regulation mechanism, also in vivo: (a) Studies on the polymerase-associated transcription kinase revealed that at appropriate ATP levels, GSH concentrations similar to those in vivo are sufficient to modulate the kinase activity; (b) GSH measurements from isolated mustard chloroplasts showed considerable differences in response to light intensity; (c) this was reflected by run-on transcription rates in isolated chloroplasts that were generally higher if organelles were prepared from seedlings incubated under high-light as compared with growth-light conditions; (d) the notion of a general transcriptional switch was strengthened by in vitro experiments showing that the kinase not only affects the transcription of a photosynthetic gene (psbA) but also that of a non-photosynthetic gene (trnQ); and (e) the polymerase-kinase complex revealed specific differences in the phosphorylation state of polypeptides depending on the light intensity to which the seedlings had been exposed prior to chloroplast isolation. Taken together, these data are consistent with GSH and phosphorylation-dependent regulation of chloroplast transcription in vivo.


Assuntos
Cloroplastos/genética , RNA Polimerases Dirigidas por DNA/metabolismo , Glutationa/metabolismo , Luz , Mostardeira/genética , Proteínas Quinases/metabolismo , Trifosfato de Adenosina , Cloroplastos/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Mostardeira/efeitos da radiação , Oxirredução , Fosforilação/efeitos da radiação , Complexo de Proteínas do Centro de Reação Fotossintética/genética , Complexo de Proteínas do Centro de Reação Fotossintética/efeitos da radiação , Complexo de Proteína do Fotossistema II , Transdução de Sinais , Transcrição Gênica
8.
J Lab Clin Med ; 138(2): 130-8, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11477380

RESUMO

Although iron chelation therapy results in a significant improvement in well-being and life expectancy of thalassemic patients with transfusional iron overload, failure to achieve these goals in a substantial proportion of patients underlines the need for improved methods of treatment. In the present studies we used selective radioactive iron probes of hepatocellular and reticuloendothelial (RE) iron stores in hypertransfused rats and iron-loaded heart cells to compare the source of iron chelated in vivo by deferoxamine (DFO) or by deferiprone (L1) and its mode of excretion, to examine the ability of DFO and L1 to remove iron directly from iron-loaded myocardial cells, and to examine the mechanism of their combined interaction through a possible additive or synergistic effect. Our results indicate that L1 given orally is 1.6 to 1.9 times more effective in rats, on a weight-per-weight basis, than parenteral DFO in promoting the excretion of storage iron from parenchymal iron stores but shows no advantage over DFO in promoting RE iron excretion. Simultaneous administration of DFO and L1 results in an increase in chelating effect that is additive but not synergistic. The magnitude of this additive effect is identical to an increase in the equivalent (weight or molar) dose of DFO alone rather than the sum of the separate effects of L1 and DFO. This finding is most probably the result of a transfer of chelated iron from L1 to DFO. These observations may have practical implications for current efforts to design better therapeutic strategies for the management of transfusional iron overload.


Assuntos
Desferroxamina/farmacologia , Quelantes de Ferro/farmacologia , Sobrecarga de Ferro/tratamento farmacológico , Ferro/metabolismo , Miocárdio/metabolismo , Piridonas/farmacologia , Animais , Transfusão de Sangue , Células Cultivadas , Deferiprona , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Feminino , Radioisótopos de Ferro , Miocárdio/citologia , Ratos , Ratos Wistar
9.
J Am Chem Soc ; 123(18): 4211-22, 2001 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-11457186

RESUMO

The geometry of the secondary radical pair P700(+)A1(-), in photosystem I (PSI) from the deuterated and 15N-substituted cyanobacterium Synechococcus lividus, has been determined by high time resolution electron paramagnetic resonance (EPR), performed at three different microwave frequencies. Structural information is extracted from light-induced quantum beats observed in the transverse magnetization of P700(+)A1(-) at early times after laser excitation. A computer analysis of the two-dimensional Q-band experiment provides the orientation of the various magnetic tensors of with respect to a magnetic reference frame. The orientation of the cofactors of the primary donor in the g-tensor system of is then evaluated by analyzing time-dependent X-band EPR spectra, extracted from a two-dimensional data set. Finally, the cofactor arrangement of P700(+)A1(-) in the photosynthetic membrane is deduced from angular-dependent W-band spectra, observed for a magnetically aligned sample. Thus, the orientation of the g-tensor of P700(+) with respect to a chlorophyll based reference system could be determined. The angle between the g1(z) axis and the chlorophyll plane normal is found to be 29 +/- 7 degrees, while the g1(y) axis lies in the chlorophyll plane. In addition, a complete structural model for the reduced quinone acceptor, A1(-), is evaluated. In this model, the quinone plane of is found to be inclined by 68 +/- 7 degrees relative to the membrane plane, while the P700(+)-A1(-) axis makes an angle of 35 +/- 6 degrees with the membrane normal. All of these values refer to the charge separated state, observed at low temperatures, where forward electron transfer to the iron-sulfur centers is partially blocked. Preliminary room temperature studies of P700(+)A1(-), employing X-band quantum beat oscillations, indicate a different orientation of A1(-) in its binding pocket. A comparison with crystallographic data provides information on the electron-transfer pathway in PSI. It appears that quantum beats represent excellent structural probes for the short-lived intermediates in the primary energy conversion steps of photosynthesis.


Assuntos
Cianobactérias/química , Complexo de Proteínas do Centro de Reação Fotossintética/química , Membrana Celular/química , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres/química , Complexos de Proteínas Captadores de Luz , Complexo de Proteína do Fotossistema I , Conformação Proteica
11.
FEBS Lett ; 492(1-2): 39-44, 2001 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-11248233

RESUMO

Here we show that human protein kinase C mu (PKC mu) activates the mitogen-activated protein kinase (MAPK). Transient expression of constitutive active PKC mu leads to an activation of Raf-1 kinase as demonstrated by in vitro phosphorylation of MAPK. PKC mu enhances transcriptional activity of a basal thymidine kinase promotor containing serum response elements (SREs) as shown by luciferase reporter gene assays. SRE driven gene activation by PKC mu is triggered by the Elk-1 ternary complex factor. PKC mu-mediated activation of SRE driven transcription can be inhibited by the MEK1 inhibitor PD98059. In contrast to the activation of the p42/ERK1 MAPK cascade, transient expression of constitutive active PKC mu does neither affect c-jun N-terminal kinase nor p38 MAPK.


Assuntos
Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase C/metabolismo , Fatores de Transcrição , Células Cultivadas , Proteínas de Ligação a DNA/fisiologia , Ativação Enzimática , Regulação Enzimológica da Expressão Gênica , Genes Reporter , Humanos , Luciferases/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Nucleares/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Proteínas Proto-Oncogênicas c-raf/metabolismo , Fator de Resposta Sérica , Transcrição Gênica , Ativação Transcricional , Transfecção , Proteínas Elk-1 do Domínio ets
12.
Blood ; 97(4): 1115-22, 2001 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-11159545

RESUMO

ICL670A (formerly CGP 72 670) or 4-[3,5-bis-(hydroxyphenyl)-1,2,4-triazol-1-yl]- benzoic acid is a tridentate iron-selective synthetic chelator of the bis-hydroxyphenyl-triazole class of compounds. The present studies used selective radioiron probes of hepatocellular and reticuloendothelial (RE) iron stores in hypertransfused rats and iron-loaded heart cells to define the source of iron chelated in vivo by ICL670A and its mode of excretion, to examine its ability to remove iron directly from iron-loaded myocardial cells, and to examine its ability to interact with other chelators through a possible additive or synergistic effect. Results indicate that ICL670A given orally is 4 to 5 times more effective than parenteral deferoxamine (DFO) in promoting the excretion of chelatable iron from hepatocellular iron stores. The pattern of iron excretion produced by ICL670A is quite different from that of DFO and all iron excretion is restricted to the bile regardless of whether it is derived from RE or hepatocellular iron stores. Studies in heart cell cultures have shown a favorable interaction between DFO and ICL670A manifested in improved chelating efficiency of ICL670A, which is most probably explained by an exchange of chelated iron between ICL670A and DFO. These unique chelating properties of ICL670A may have practical implications for current efforts to design better therapeutic strategies for the management of transfusional iron overload.


Assuntos
Benzoatos/uso terapêutico , Hepatócitos/metabolismo , Quelantes de Ferro/uso terapêutico , Sobrecarga de Ferro/tratamento farmacológico , Radioisótopos de Ferro/farmacocinética , Sistema Fagocitário Mononuclear/metabolismo , Reação Transfusional , Triazóis/uso terapêutico , Animais , Benzoatos/química , Benzoatos/farmacocinética , Bile/metabolismo , Células Cultivadas , Deferasirox , Desferroxamina/farmacocinética , Desferroxamina/uso terapêutico , Avaliação Pré-Clínica de Medicamentos , Transfusão de Eritrócitos , Eritrócitos Anormais , Fezes/química , Feminino , Ferritinas/farmacocinética , Coração/efeitos dos fármacos , Temperatura Alta , Injeções Intravenosas , Quelantes de Ferro/química , Quelantes de Ferro/farmacocinética , Sobrecarga de Ferro/metabolismo , Radioisótopos de Ferro/urina , Fígado/metabolismo , Camundongos , Estrutura Molecular , Miocárdio/citologia , Miocárdio/metabolismo , Especificidade de Órgãos , Ratos , Ratos Wistar , Distribuição Tecidual , Triazóis/química , Triazóis/farmacocinética , Urina/química
13.
Zentralbl Gynakol ; 122(9): 457-71, 2000.
Artigo em Alemão | MEDLINE | ID: mdl-11050762

RESUMO

This article analyses, after introductory comments on the legal situation in the German Empire and the Weimar Republic, the legal basis for induced abortions during National Socialist rule in Germany. During this period the first legal definition for eugenically and medically indicated abortions was established. At the same time the prohibition of induced abortions outside these criteria was controlled more strictly and violations were punished more severely. This concerned abortions mainly for social reasons. The intention was to legalize abortion for those deemed "less worthy" while, at the same time, to minimise the number of abortions of those considered as "more valuable" to society. The main thrust of this policy was to increase the birth rate of "valuable" citizens. The second part of this paper focuses on eugenic and medical abortions at the University of Freiburg's Maternity Hospital.


Assuntos
Aborto Induzido/história , Legislação Médica/história , Sistemas Políticos/história , Eugenia (Ciência)/história , Feminino , Alemanha , História do Século XX , Humanos , Gravidez , Esterilização Involuntária/história
14.
J Biol Chem ; 275(32): 24601-7, 2000 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-10831594

RESUMO

We identified the multifunctional chaperon protein p32 as a protein kinase C (PKC)-binding protein interacting with PKCalpha, PKCzeta, PKCdelta, and PKC mu. We have analyzed the interaction of PKC mu with p32 in detail, and we show here in vivo association of PKC mu, as revealed from yeast two-hybrid analysis, precipitation assays using glutathione S-transferase fusion proteins, and reciprocal coimmunoprecipitation. In SKW 6.4 cells, PKC mu is constitutively associated with p32 at mitochondrial membranes, evident from colocalization with cytochrome c. p32 interacts with PKC mu in a compartment-specific manner, as it can be coimmunoprecipitated mainly from the particulate and not from the soluble fraction, despite the presence of p32 in both fractions. Although p32 binds to the kinase domain of PKC mu, it does not serve as a substrate. Interestingly, PKC mu-p32 immunocomplexes precipitated from the particulate fraction of two distinct cell lines, SKW 6.4 and 293T, show no detectable substrate phosphorylation. In support of a kinase regulatory function of p32, addition of p32 to in vitro kinase assays blocked, in a dose-dependent manner, aldolase but not autophosphorylation of PKC mu, suggesting a steric hindrance of substrate within the kinase domain. Together, these findings identify p32 as a novel, compartment-specific regulator of PKC mu kinase activity.


Assuntos
Receptores de Hialuronatos , Glicoproteínas de Membrana , Chaperonas Moleculares/metabolismo , Proteína Quinase C/metabolismo , Receptores de Complemento/metabolismo , Animais , Linfócitos B , Sítios de Ligação , Proteínas de Transporte , Linhagem Celular , Clonagem Molecular , Glutationa Transferase , Complexo de Golgi/metabolismo , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno , Mitocôndrias/metabolismo , Proteínas Mitocondriais , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Ligação Proteica , Proteínas Recombinantes de Fusão/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Spodoptera , Transfecção
15.
Biochem Biophys Res Commun ; 269(2): 382-6, 2000 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-10708561

RESUMO

Lipoamide dehydrogenase deficiency is an inborn error of several metabolic pathways, including pyruvate metabolism, Krebs cycle, and branched-chain amino acid degradation. The clinical course is variable, ranging from infantile neurodegenerative disease to recurrent episodes of liver failure or myoglobinuria starting later in life. In contrast, residual enzymatic activity in muscle tissue spans over a narrow range. Despite the recent elucidation of the underlying molecular pathology in most patients, relationships between the genotype and the biochemical and clinical phenotype remain unclear. In order to find a suitable assay for the prediction of clinical outcome and assessment of treatment, we have evaluated enzymatic activities and energetic states in fibroblasts from lipoamide dehydrogenase-deficient patients representing three different phenotypes and genotypes. Direct relationships between clinical parameters such as age of onset and disease severity and biochemical characteristics, including lipoamide dehydrogenase activity, pyruvate dehydrogenase complex activity, and ATP production ratio in fibroblasts, were identified. Clinical parameters were not reflected by lactate/pyruvate ratio. ATP production rate was in direct relationship with the severity of the neurological involvement; the patient with reduced ATP synthesis to 30% of the control mean had a severe neurodegenerative disease, whereas ATP synthesis values above 45% were associated with a more favorable course. Incubation of the patients' fibroblasts with dichloroacetate coupled with thiamin resulted in slight but significant improvement of the cell energetic state.


Assuntos
Trifosfato de Adenosina/biossíntese , Di-Hidrolipoamida Desidrogenase/deficiência , Erros Inatos do Metabolismo/metabolismo , Adulto , Linhagem Celular , Di-Hidrolipoamida Desidrogenase/metabolismo , Humanos , Músculos/enzimologia , Estresse Oxidativo , Complexo Piruvato Desidrogenase/metabolismo
16.
Curr Genet ; 37(1): 45-52, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10672444

RESUMO

The mustard chloroplast DNA region spanning the ycf3 gene and part of the psaAB operon was investigated. The ycf3 gene reveals two class-II introns that are removed during processing to give a mature 0.7-kb transcript, but no RNA editing seems to be involved. RNase protection and RT-PCR experiments suggest cotranscription of ycf3 with the downstream psaA gene, possibly from a NEP promoter upstream of ycf3, whereas distinct ycf3 and psaA transcripts are each initiated from PEP promoters. This situation is reminiscent of that for the trnK-psbA gene region. The implications for light-regulated versus light-independent expression of photosystem core-protein genes are discussed.


Assuntos
DNA de Cloroplastos/genética , Genes de Plantas/genética , Complexos de Proteínas Captadores de Luz , Mostardeira/genética , Complexo de Proteína do Fotossistema I , Plantas Medicinais , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , Transcrição Gênica/genética , Sequência de Aminoácidos , Sequência de Bases , Éxons/genética , Regulação da Expressão Gênica de Plantas , Íntrons/genética , Proteínas de Membrana/genética , Dados de Sequência Molecular , Mostardeira/citologia , Mostardeira/crescimento & desenvolvimento , Óperon/genética , Complexo de Proteínas do Centro de Reação Fotossintética/química , Complexo de Proteínas do Centro de Reação Fotossintética/genética , Proteínas de Plantas/genética , Regiões Promotoras Genéticas/fisiologia , Splicing de RNA/genética , RNA de Cloroplastos/análise , RNA de Cloroplastos/genética , RNA Mensageiro/análise , Alinhamento de Sequência , Regiões Terminadoras Genéticas/genética , Regiões Terminadoras Genéticas/fisiologia
17.
Eur J Biochem ; 267(1): 253-61, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10601874

RESUMO

We previously identified two multisubunit plastid RNA polymerases termed A and B. The B enzyme has a bacterial-type polypeptide composition and is sensitive to the prokaryotic transcription inhibitor rifampicin (Rif); the A enzyme has a more complex subunit structure and is Rif-resistant. Here we report results of N-terminal sequencing and MS carried out with the A enzyme, which establish that the latter contains rpo gene products and is structurally related to the B enzyme. Furthermore, evidence is provided that the A enzyme can be converted into a Rif-sensitive enzyme form in a phosphorylation-dependent manner in vitro by a treatment that results in depletion of a beta-like subunit. Database searches using sequence information derived from additional polypeptides that are present in purified A preparations revealed sequence similarity with chloroplast proteins involved in RNA processing and redox control. This proteomics approach thus points to the complexity of the chloroplast transcription apparatus and its interconnections with post-transcriptional and signalling mechanisms.


Assuntos
Cloroplastos/enzimologia , Mostardeira/enzimologia , Plantas Medicinais , RNA Polimerase I/química , RNA Polimerase I/metabolismo , Fosfatase Alcalina/metabolismo , Sequência de Aminoácidos , Cloroplastos/genética , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Genes de Plantas/genética , Dados de Sequência Molecular , Peso Molecular , Mostardeira/citologia , Mostardeira/genética , Peptídeos/química , Peptídeos/genética , Peptídeos/isolamento & purificação , Fosforilação , RNA Polimerase I/antagonistas & inibidores , RNA Polimerase I/genética , RNA Polimerase II/química , RNA Polimerase II/genética , Rifampina/farmacologia , Alinhamento de Sequência , Análise de Sequência de Proteína , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Superóxido Dismutase/química
18.
FEBS Lett ; 461(1-2): 68-72, 1999 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-10561498

RESUMO

Bruton's tyrosine kinase (Btk) is considered an essential signal transducer in B-cells. Mutational defects are associated with a severe immunodeficiency syndrome, X-chromosome linked agammaglobulinemia (XLA). Here we show by coimmunoprecipitation that a member of the protein kinase C (PKC) family, PKCmu, is constitutively associated with Btk. Neither antigen receptor (Ig) crosslinking nor stimulation of B-cells with phorbol ester or H(2)O(2) affected Btk/PKCmu interaction. GST precipitation analysis revealed association of the Btk pleckstrin/Tec homology domain with PKCmu. Transient overexpression of PKCmu deletion mutants as well as expression of selected PKCmu domains in 293T cells revealed that both the kinase domain and the regulatory C1 region are independently capable of binding to the Btk PH-TH domain. These data show the existence of a PKCmu/Btk complex in vivo and identify two PKCmu domains that participate in Btk interaction.


Assuntos
Ligação Proteica , Proteína Quinase C/metabolismo , Proteínas Tirosina Quinases/metabolismo , Tirosina Quinase da Agamaglobulinemia , Linhagem Celular , Glutationa Transferase/metabolismo , Humanos , Modelos Biológicos , Testes de Precipitina , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes , Transdução de Sinais , Transfecção
19.
Plant Mol Biol ; 39(5): 1013-23, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10344206

RESUMO

The major RNA polymerase from mustard chloroplasts is a multi-subunit enzyme consisting of core components and associated factors. Among the latter is a heterotrimeric factor named PTK (plastid transcription kinase) because of its serine/threonine-type protein kinase activity. PTK activity itself depends on its phosphorylation state. In addition, we show that it responds to glutathione but not to other redox-reactive reagents that were tested, and both glutathione and phosphorylation act antagonistically. Using a homologous in vitro system, we find that PTK selectively phosphorylates subunit(s) of plastid RNA polymerase and is involved in determining the level of faithful transcription from the chloroplast psbA promoter. Together, these results establish a role for phosphorylation and redox state in the regulation of plastid gene expression.


Assuntos
Cloroplastos/enzimologia , RNA Polimerases Dirigidas por DNA/metabolismo , Mostardeira/enzimologia , Plantas Medicinais , Proteínas Serina-Treonina Quinases/metabolismo , Cloroplastos/efeitos dos fármacos , Cloroplastos/genética , Glutationa/farmacologia , Mostardeira/efeitos dos fármacos , Mostardeira/genética , Oxirredução , Peptídeos/metabolismo , Complexo de Proteínas do Centro de Reação Fotossintética/genética , Complexo de Proteína do Fotossistema II , Regiões Promotoras Genéticas , Especificidade por Substrato , Transcrição Gênica
20.
J Biol Chem ; 274(14): 9258-64, 1999 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-10092600

RESUMO

Recent studies have documented direct interaction between 14-3-3 proteins and key molecules in signal transduction pathways like Ras, Cbl, and protein kinases. In T cells, the 14-3-3tau isoform has been shown to associate with protein kinase C theta and to negatively regulate interleukin-2 secretion. Here we present data that 14-3-3tau interacts with protein kinase C mu (PKCmu), a subtype that differs from other PKC members in structure and activation mechanisms. Specific interaction of PKCmu and 14-3-3tau can be shown in the T cell line Jurkat by immunocoprecipitiation and by pulldown assays of either endogenous or overexpressed proteins using PKCmu-specific antibodies and GST-14-3-3 fusion proteins, respectively. Using PKCmu deletion mutants, the 14-3-3tau binding region is mapped within the regulatory C1 domain. Binding of 14-3-3tau to PKCmu is significantly enhanced upon phorbol ester stimulation of PKCmu kinase activity in Jurkat cells and occurs via a Cbl-like serine containing consensus motif. However, 14-3-3tau is not a substrate of PKCmu. In contrast 14-3-3tau strongly down-regulates PKCmu kinase activity in vitro. Moreover, overexpression of 14-3-3tau significantly reduced phorbol ester induced activation of PKCmu kinase activity in intact cells. We therefore conclude that 14-3-3tau is a negative regulator of PKCmu in T cells.


Assuntos
Proteína Quinase C/metabolismo , Proteínas/fisiologia , Transdução de Sinais , Tirosina 3-Mono-Oxigenase , Proteínas 14-3-3 , Sítios de Ligação , Regulação para Baixo , Humanos , Células Jurkat , Fosforilação , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/genética , Serina/metabolismo , Linfócitos T/enzimologia , Transfecção
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA