Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 54
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Ann Oncol ; 33(11): 1186-1199, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35988656

RESUMO

BACKGROUND: Germline variant evaluation in precision oncology opens new paths toward the identification of patients with genetic tumor risk syndromes and the exploration of therapeutic relevance. Here, we present the results of germline variant analysis and their clinical implications in a precision oncology study for patients with predominantly rare cancers. PATIENTS AND METHODS: Matched tumor and control genome/exome and RNA sequencing was carried out for 1485 patients with rare cancers (79%) and/or young adults (77% younger than 51 years) in the National Center for Tumor Diseases/German Cancer Consortium (NCT/DKTK) Molecularly Aided Stratification for Tumor Eradication Research (MASTER) trial, a German multicenter, prospective, observational precision oncology study. Clinical and therapeutic relevance of prospective pathogenic germline variant (PGV) evaluation was analyzed and compared to other precision oncology studies. RESULTS: Ten percent of patients (n = 157) harbored PGVs in 35 genes associated with autosomal dominant cancer predisposition, whereof up to 75% were unknown before study participation. Another 5% of patients (n = 75) were heterozygous carriers for recessive genetic tumor risk syndromes. Particularly, high PGV yields were found in patients with gastrointestinal stromal tumors (GISTs) (28%, n = 11/40), and more specifically in wild-type GISTs (50%, n = 10/20), leiomyosarcomas (21%, n = 19/89), and hepatopancreaticobiliary cancers (16%, n = 16/97). Forty-five percent of PGVs (n = 100/221) supported treatment recommendations, and its implementation led to a clinical benefit in 40% of patients (n = 10/25). A comparison of different precision oncology studies revealed variable PGV yields and considerable differences in germline variant analysis workflows. We therefore propose a detailed workflow for germline variant evaluation. CONCLUSIONS: Genetic germline testing in patients with rare cancers can identify the very first patient in a hereditary cancer family and can lead to clinical benefit in a broad range of entities. Its routine implementation in precision oncology accompanied by the harmonization of germline variant evaluation workflows will increase clinical benefit and boost research.


Assuntos
Neoplasias , Adulto Jovem , Humanos , Neoplasias/diagnóstico , Neoplasias/genética , Neoplasias/terapia , Mutação em Linhagem Germinativa , Predisposição Genética para Doença , Estudos Prospectivos , Síndrome , Medicina de Precisão/métodos
2.
Hautarzt ; 60(10): 826-9, 2009 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-19229504

RESUMO

Patients treated with TNF-alpha inhibitors frequently have serum autoantibodies, but only a few develop clinically apparent lupus erythematosus. The TNF-alpha inhibitor adalimumab is a fully humanized antibody and seems to induce autoantibodies less frequently than other drugs of this group. We report on a patient with rheumatoid arthritis, who developed anti-histone antibodies and lupus tumidus after eight months on adalimumab therapy.


Assuntos
Anticorpos Monoclonais/efeitos adversos , Toxidermias/diagnóstico , Lúpus Eritematoso Cutâneo/induzido quimicamente , Lúpus Eritematoso Cutâneo/diagnóstico , Adalimumab , Adulto , Anti-Inflamatórios/efeitos adversos , Anticorpos Monoclonais Humanizados , Toxidermias/etiologia , Toxidermias/prevenção & controle , Feminino , Humanos , Lúpus Eritematoso Cutâneo/prevenção & controle
3.
Hautarzt ; 59(9): 724-7, 2008 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-18465064

RESUMO

A woman with psoriasis vulgaris and psoriatic arthritis developed granulomatous rosacea after four weeks of therapy with etanercept. When this agent was stopped, her skin lesions rapidly resolved with topical therapy, suggesting a causal relationship between the skin lesions and drug intake. To the best of our knowledge, this is the first report on rosacea as granulomatous cutaneous adverse drug reaction caused by etanercept. No relapse of skin changes appeared under extended and successful anti-psoriatic therapy with infliximab.


Assuntos
Anticorpos Monoclonais/administração & dosagem , Imunoglobulina G/efeitos adversos , Imunoglobulina G/uso terapêutico , Psoríase/tratamento farmacológico , Receptores do Fator de Necrose Tumoral/uso terapêutico , Rosácea/induzido quimicamente , Rosácea/prevenção & controle , Idoso , Anti-Inflamatórios não Esteroides/efeitos adversos , Anti-Inflamatórios não Esteroides/uso terapêutico , Fármacos Dermatológicos/administração & dosagem , Fármacos Dermatológicos/efeitos adversos , Etanercepte , Feminino , Humanos , Infliximab , Psoríase/complicações , Prevenção Secundária , Resultado do Tratamento
4.
Mech Ageing Dev ; 40(3): 261-88, 1987 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3431165

RESUMO

Uptake of dioctadecylindocarbocyanine (DiI)-labelled low density lipoproteins (LDL) by peripheral blood lymphocytes (PBL) from young healthy donors has been characterized by flow cytometric analysis. The receptor positive cells were primarily (greater than 70%) T cells. Saturation and competition studies were performed with freshly isolated PBL as well as after a 2-3-day incubation in cholesterol-free medium. In both cases uptake was specific for LDL and not high density lipoprotein. It was also abrogated by chemical modification of apo B, and was not shown by PBL from a patient with familial hypercholesterolemia. DiI-LDL-uptake by cells from elderly donors was compared with that of PBL from young donors. There was a clear increase in uptake by freshly isolated PBL from aged donors which was shown not to stem from underlying "sickness". In contrast, uptake by pre-incubated cells was very variable, in terms of percentage receptor-positive cells and the level of uptake by those cells. However, LDL rescued mevinolin-suppressed mitogen responses from both old and young donors indicating that there is no impairment of uptake or degradation of LDL by PBL from the elderly.


Assuntos
Envelhecimento , Lipoproteínas LDL/farmacocinética , Linfócitos/metabolismo , Adulto , Idoso , Anticorpos Monoclonais/imunologia , Separação Celular , Feminino , Citometria de Fluxo , Humanos , Técnicas In Vitro , Lipídeos/sangue , Lipoproteínas LDL/sangue , Masculino , Receptores de LDL/metabolismo
5.
J Histochem Cytochem ; 34(9): 1217-21, 1986 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2426348

RESUMO

We have developed a simple method for comparing the relative fluorescence intensity (FI) of flow cytometry histograms. It entails assessment of the FI (equivalent to the fluorescence-activated cell sorter (FACS) channel) of the 50th or 75th percentiles of either positively stained cells or the total cell population. We illustrate the method with dilution curves of 1) monoclonal antibodies against the T4 surface antigen of human peripheral blood lymphocytes and 2) fluorescent low density lipoprotein (LDL) binding to the human peripheral blood lymphocytes LDL receptor. We demonstrate the versatility of the method by characterizing the binding properties of fluorescent LDL to their receptors. Binding was shown to be specific and of high affinity, and to reach a steady state plateau at about 2 hr; the affinity of fluorescent LDL for the receptor was found to be two to three times higher than that of the unlabeled LDL.


Assuntos
Antígenos de Superfície/análise , Citometria de Fluxo/métodos , Receptores de LDL/análise , Linfócitos T Auxiliares-Indutores/metabolismo , Anticorpos Monoclonais , Antígenos de Diferenciação de Linfócitos T , Humanos , Coloração e Rotulagem
6.
Am J Cardiol ; 80(3A): 162A-167A, 1997 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-9293972

RESUMO

Early action of angiotensin-converting enzyme (ACE) inhibitors after myocardial infarction (MI) has been shown in large scale clinical trials to reduce mortality over the first weeks. However, the mechanisms involved are yet unclear and several trials showed a tendency toward a small, albeit unexpected, rise in cardiogenic shock or mortality. Since cardiopulmonary exercise testing (CPX) has become a "gold standard" in assessing the severity of heart failure, we studied--after finishing a pilot trial--the effect of captopril versus placebo in 208 patients who were individually titrated (titrated dose, mean 46/69 mg/day after 7 days/4 weeks, respectively) in order to preserve their blood pressure in the acute phase of myocardial infarction; we followed the development of congestive heart failure (CHF) over 4 weeks by measuring oxygen consumption. After 4 weeks, overall oxygen consumption at the anaerobic threshold (VO2-AT; 13.7 vs 13.1), maximal oxygen consumption (VO2max 19.3 vs 18.9 mL/kg per min) and exercise duration (896 vs 839 sec) showed a nonsignificant difference in favor of the captopril group. The predefined, categorized, combined endpoint of severe heart failure or death (heart failure necessitating ACE inhibition, VO2max < 10 mL/kg per min, or death) was significantly reduced in the captopril group (n = 7/104) versus placebo (n = 18/104; p = 0.03). Differences were mainly caused by fewer CHF events (delta n = 10). We conclude that ACE inhibition with individualized dose titration markedly reduces the 4-week incidence of severe heart failure or death; > 10 patients per 100 treated gained major benefits from this therapy.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Captopril/farmacologia , Cardiomegalia/prevenção & controle , Teste de Esforço , Insuficiência Cardíaca/prevenção & controle , Infarto do Miocárdio/complicações , Adulto , Idoso , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Captopril/uso terapêutico , Dióxido de Carbono/metabolismo , Cardiomegalia/diagnóstico por imagem , Cardiomegalia/etiologia , Método Duplo-Cego , Ecocardiografia , Feminino , Alemanha , Insuficiência Cardíaca/etiologia , Ventrículos do Coração/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/fisiopatologia , Consumo de Oxigênio/efeitos dos fármacos , Resultado do Tratamento
7.
Immunobiology ; 176(4-5): 450-64, 1988 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-3292405

RESUMO

A correlation has been sought between the effects of lipids on membrane fluidity and mitogen responsiveness of human peripheral blood lymphocytes (PBL). Cholesterol and the reputedly potent membrane fluidizing agent AL721 (1) were used for these studies. However, the large AL721 induced increase in membrane "fluidity", assessed by steady state polarization of the probe 1,6-diphenyl-1,3,5-hexatriene (DPH), was found to be an artefact arising from lipid uptake by monocytes. Mitogen responses were enhanced by AL721 but unaffected by cholesterol. It is concluded that AL721 does not exert its effect through enhanced triggering of cells by altered membrane fluidity but rather that lymphocytes require an exogenous source of phospholipids/triglycerides for optimal growth in vitro, although they can synthesize sufficient cholesterol to meet their own needs.


Assuntos
Glicerídeos/metabolismo , Ativação Linfocitária , Fluidez de Membrana , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/metabolismo , Linfócitos T/imunologia , Adulto , Transporte Biológico , Células Cultivadas , Meios de Cultura , Replicação do DNA , Combinação de Medicamentos/metabolismo , Feminino , Imunofluorescência , Antígenos HLA-DR/análise , Humanos , Masculino , Monócitos/fisiologia , Linfócitos T/citologia , Linfócitos T/fisiologia
8.
Artigo em Inglês | MEDLINE | ID: mdl-9194150

RESUMO

1. The kava-pyrones kawain and dihydromethysticin are constituents of Piper methysticum which exert anticonvulsant, analgesic and anxiolytic properties. 2. In the present study the effect of these kava-pyrones were tested on field potential changes (fp) induced by omission of the extracellular Mg2+, recorded from the area CA1 and CA3 of the hippocampal slice preparation of guinea pigs. These fp are generated by an activation of NMDA receptors and voltage dependent calcium channels. 3. Kawain and dihydromethysticin reduced reversibly the frequency of occurrence of fp in a concentration range from 5 to 40 mumol/l and 10 to 40 mumol/l, respectively. 4. Reduction of the fp frequency after addition of subthreshold concentrations of 5 mumol/l kawain and 10 mumol/l dihydromethysticin indicated additive actions of both drugs. 5. Since the serotonin-1A agonist ipsapirone also exerts anxiolytic effects, subthreshold concentrations of kawain or dihydromethysticin were combined with a subthreshold concentration of ipsapirone in another set of experiments. Combining kawain and ipsapirone or dihydromethysticin and ipsapirone caused a reduction of the rate of fp to 0.76 and 0.81 of the baseline value, respectively. 6. The findings suggest that (i) single constituents of Piper methysticum may have additive actions, (ii) that the two components kawain and dihydromethysticin may enhance the effects of the anxiolytic serotonin-1A agonist ipsapirone and (iii) that activation of NMDA receptors and/or voltage dependent calcium channels may be involved in the elementary mechanism of action of some kava-pyrones.


Assuntos
Anticonvulsivantes/farmacologia , Hipocampo/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Pironas/farmacologia , Animais , Relação Dose-Resposta a Droga , Cobaias
9.
Eur Neuropsychopharmacol ; 9(1-2): 171-6, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10082244

RESUMO

Kava pyrones extracted from pepper Piper methysticum are pharmacologically active compounds. Since kava pyrones exhibit anticonvulsive, analgesic and centrally muscle relaxing properties, the influence of a synthetic kava pyrone, (+/-)-kavain, on voltage-dependent ion channel currents was studied. Effects of (+/-)-kavain on voltage-activated inward currents were analysed in cultured dorsal root ganglion cells derived from neonatal rats. Voltage-activated Ca2+ and Na+ currents were elicited in the whole-cell configuration of the patch clamp technique. Extracellularly applied (+/-)-kavain dissolved in hydrous salt solutions reduced voltage-activated Ca2+ and Na+ channel currents within 3-5 min. As the solubility of (+/-)-kavain in hydrous solutions is low, dimethyl sulfoxide (DMSO) was added to the saline as a solvent for the drug in most experiments. When (+/-)-kavain was dissolved in DMSO, the drug induced a fast and pronounced reduction of both Ca2+ and Na+ currents, which partly recovered within 2-5 min even in the presence of the drug. The present study indicates that (+/-)-kavain reduces currents through voltage-activated Na+ and Ca2+ channels.


Assuntos
Animais Recém-Nascidos/fisiologia , Ansiolíticos/farmacologia , Gânglios Espinais/citologia , Gânglios Espinais/efeitos dos fármacos , Ativação do Canal Iônico/efeitos dos fármacos , Canais Iônicos/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Pironas/farmacologia , Animais , Canais de Cálcio/efeitos dos fármacos , Dimetil Sulfóxido , Eletrofisiologia , Técnicas In Vitro , Ratos , Canais de Sódio/efeitos dos fármacos , Solventes , Estereoisomerismo , Tetrodotoxina/farmacologia
10.
Int J Cardiol ; 6(2): 167-88, 1984 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-6469404

RESUMO

We have developed a new high resolution ECG equipment for recording cardiac microvolt potentials from the body surface. Noise reduction has been achieved by specially designed suction electrodes, by spatial averaging of the electrocardiograms from four electrode pairs, using extremely low noise amplifiers, by performing registrations within a Faraday cage, and by teaching the patient to relax during end expiratory breath holding. Fourteen young males (controls) and 30 patients with various cardiac diseases (27 with CHD) were studied. In normals ventricular late potentials were not seen, but in 12/30 patients clearcut diastolic potentials were found. In 7/12 patients with positive findings, late potentials appeared beat-by-beat, in 5/12 patients those signals occurred intermittently, in 11/30 patients questionably, and in the remaining 5/30 patients no late potentials were recorded. One patient with the Romano-Ward syndrome revealed phases with stable beat-by-beat and intermittently occurring ventricular late potentials. These results demonstrate the feasibility of continuous non-invasive recording of ventricular late potentials, whose clinical and prognostic significance remains to be established.


Assuntos
Eletrocardiografia/métodos , Cardiopatias/fisiopatologia , Ventrículos do Coração/fisiopatologia , Adolescente , Adulto , Idoso , Fascículo Atrioventricular/fisiopatologia , Doença das Coronárias/fisiopatologia , Eletrocardiografia/instrumentação , Feminino , Sistema de Condução Cardíaco/fisiopatologia , Cardiopatias Congênitas/fisiopatologia , Cardiopatias/diagnóstico , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/fisiopatologia , Taquicardia Paroxística/fisiopatologia
11.
Oecologia ; 74(1): 122-127, 1987 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28310424

RESUMO

The composition of the vacuolar sap of Chara vulgaris growing in a brackish water lake was estimated weekly over 2 years (1984-1985). The ionic concentrations of the main cations Na+, K+, Ca2+, and Mg2+ and the anion Cl- varied depending on cell age, developmental state, and season. The average of all measurements (in mM) was Na+: 35, K+: 106, Ca2+: 7, Mg2+: 23, Cl-: 101, SO 2-4 : 20, and PO 3-4 : 5. At the onset of growth in May/June the ionic content was lower compared to the mean value for the year, steadily increasing until it reached its maximum above the annual mean in winter. During the period of fructification (sexual reproduction: formation of antheridia and oogonia), when up to 100 mM sucrose was accumulated in the vacuolar sap, ionic content was lowest. This resulted in a fairly constant osmotic potential throughout the year. Mg2+ and Ca2+ concentrations were correlated with the physiological age of the cells.

12.
Clin Cardiol ; 9(8): 361-8, 1986 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-3731561

RESUMO

In 70 patients (3 females and 67 males), aged 16-72 years (mean: 51 +/- 9 years), the low noise ECG was recorded from body surface by the signal averaging and the high resolution beat-to-beat techniques. We found 61 patients were suffering from coronary heart disease, 4 had atypical coronary heart disease (syndrome X), 4 had dilatative cardiomyopathy, and one had the long QT syndrome (Romano-Ward syndrome). We found the following recovery rates for ventricular late potentials within the ST segment with the averaging technique: clearcut in 13/53 patients, doubtful in 16/53 patients, and late potentials absent in 26/53 patients. With the beat-to-beat technique the following recovery rates were found: clearcut late potentials in 27/70 patients, doubtful in 23/70 patients, none in 20/70 patients, and intermittently occurring late potentials in 18/70 patients (categorized as doubtful late potentials). When comparing the detection of late potentials with both methods in individual patients, we found concordant results in 39/53 patients studied (positive with both methods in 24/53 patients, negative with both methods in 15/53 patients), and discordant results in 14/53 patients (positive with the beat-to-beat technique and negative with the averaging technique in 12 individuals, negative with the beat-to-beat technique and positive with the averaging technique in the remaining 2 patients). The correlation between the incidence of late potentials and the presence of exercise-induced myocardial ischemia (submaximal bicycle exercise) was higher when using the high resolution beat-to-beat technique, as holds also true for the correlation to complex ventricular arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Arritmias Cardíacas/fisiopatologia , Eletrocardiografia/métodos , Adolescente , Adulto , Idoso , Teste de Esforço , Feminino , Aneurisma Cardíaco/fisiopatologia , Ventrículos do Coração/fisiopatologia , Humanos , Síndrome do QT Longo/fisiopatologia , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica , Pulso Arterial , Volume Sistólico
13.
Wien Klin Wochenschr ; 100(17): 597-9, 1988 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-3263733

RESUMO

This report deals with AL 721, a reputedly potent membrane fluidizing agent. A correlation has been sought between the effects of AL 721 on membrane fluidity and mitogen responsiveness of human peripheral blood lymphocytes. The AL 721-induced increase in membrane "fluidity", as measured by fluorescence polarisation with 1,6-diphenyl-1,3,5-hexatriene, was found to be an artefact arising from lipid uptake by monocytes. Mitogen responses were enhanced by inclusion of AL 721 in the serum-free culture medium. However, this observation is more likely explained by provision of lymphocytes with nutritional lipids required for optimal growth in vitro, than altered responsiveness of "fluidized" lymphocytes.


Assuntos
Glicerídeos/farmacologia , Ativação Linfocitária/efeitos dos fármacos , Fluidez de Membrana/efeitos dos fármacos , Fosfatidilcolinas/farmacologia , Fosfatidiletanolaminas/farmacologia , Linfócitos T/efeitos dos fármacos , Adolescente , Adulto , Idoso , Combinação de Medicamentos/farmacologia , Humanos , Lipídeos de Membrana/metabolismo , Pessoa de Meia-Idade , Espectrometria de Fluorescência
14.
Aktuelle Traumatol ; 15(5): 219-21, 1985 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-2866683

RESUMO

The surgeons of the accident hospital of the relevant professional association at Ludwigshafen have been increasingly resorting to treating fresh ruptures of the Achilles tendon with fibrin adhesive only. Initially the adhesion procedure was supplemented by and adaptational suture. The essential feature of this procedure is that no suturing material whatsoever is implanted into the tendon. The surgical procedure is quicker and simpler than by suturing the tendon rupture. Up to now 52 ruptures of the Achilles tendon have been treated with fibrin adhesive at the hospital under report. Curative results were very satisfactory with the exception of one complication where a renewed injury resulted in another rupture.


Assuntos
Tendão do Calcâneo/lesões , Fator XIII/uso terapêutico , Fibrinogênio/uso terapêutico , Trombina/uso terapêutico , Adesivos Teciduais/uso terapêutico , Combinação de Medicamentos/uso terapêutico , Adesivo Tecidual de Fibrina , Humanos , Cuidados Pós-Operatórios , Ruptura , Técnicas de Sutura , Cicatrização/efeitos dos fármacos
15.
Aktuelle Traumatol ; 13(1): 1-4, 1983 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-6132525

RESUMO

The Küntscher nail has proved successful in the treatment of non-unions of the median third of the femur and lower leg after opening of the medullary cavity; in fact, this method is described in literature as the method of choice. It is based on the assumption that a sufficiently dimensioned intramedullary Küntscher nail together with the biological stimulative action of the bone meal, will result in a rapid osseous bridging of the non-union. This method has been successfully used in 128 cases even in non-unions which were close to the joint. Healing occurred in 92% of the cases. In about 11 cases it became necessary to perform a secondary operation. The high rate of infection, amounting to 12.4%, is relatively low compared with the very high rate of infective relapses following the first operation to achieve healing of the bone fractures.


Assuntos
Pinos Ortopédicos , Fixação Intramedular de Fraturas/métodos , Traumatismos da Perna/cirurgia , Pseudoartrose/cirurgia , Adulto , Humanos , Traumatismos da Perna/diagnóstico por imagem , Pseudoartrose/diagnóstico por imagem , Radiografia , Cicatrização
19.
Hautarzt ; 59(8): 649-52, 2008 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-17965839

RESUMO

Human seminal plasma allergy (HSPA) is a rare allergic reaction to specific protein fractions of seminal plasma, whereof PSA seems to be a relevant allergen. Predominantly Type I-immunoreactions can occur. The main symptoms are localized and generalized urticaria and sometimes anaphylactic symptoms. The diagnosis is based on history, skin tests and on the determination of specific IgE-levels for (un)fractionated seminal plasma. Here we report a patient with recurrent episodes of generalized urticaria after unprotected sexual intercourse and positive prick-test-reaction on seminal plasma.


Assuntos
Hipersensibilidade Imediata/etiologia , Sêmen/imunologia , Urticária/etiologia , Vulvite/etiologia , Adulto , Preservativos , Dessensibilização Imunológica , Diagnóstico Diferencial , Feminino , Humanos , Hipersensibilidade Imediata/diagnóstico , Hipersensibilidade Imediata/imunologia , Hipersensibilidade Imediata/terapia , Testes Intradérmicos , Urticária/diagnóstico , Urticária/imunologia , Urticária/terapia , Vulvite/diagnóstico , Vulvite/imunologia , Vulvite/terapia
20.
Eur J Biochem ; 187(2): 445-53, 1990 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-2298218

RESUMO

In the leaves of rye (Secale cereale L.), control mechanisms acting at multiple molecular levels contribute to a coordinate expression of the subunit polypeptides of ribulose-1,5-bisphosphate carboxylase. The relevance and hierarchy of the different control steps were evaluated by comparing the time courses of changes in levels of translatable mRNA, rates of in vivo amino acid incorporation, and the turnover of subunit polypeptides after selective interference with translation at either cytoplasmic 80S ribosomes, or at the 70S ribosomes of the chloroplast, by compartment-specific inhibitors, or by the use of 70S-ribosome-deficient leaves. The latter were generated by growing the plants at a non-permissive elevated temperature of 32 degrees C. The rates of synthesis of the two ribulose-1,5-bisphosphate carboxylase subunits were most rapidly adapted to each other by translational controls. Within 0.5-2.5 h after selective inhibition of the synthesis of either subunit, that of the other subunit made in the unaffected compartment also declined by more than 90% without any marked change in its mRNA. After prolonged inhibition (24 h) of either cytoplasmic or chloroplast protein synthesis, the levels of mRNAs for both subunits were greatly diminished. In rye, the mRNA levels for both subunits changed under all experimental conditions tested in a closely parallel manner and appeared to be always maintained in a balanced, fairly constant ratio by strong coordinate controls. Even 70S-ribosome-deficient leaves contained mRNAs for both the small and the large subunits, although only in small amounts. The mRNAs for both subunits were also markedly further decreased in 70S-ribosome-deficient leaves after application of an inhibitor of cytoplasmic translation. MDMP [2-(4-methyl-2,6-dinitroanilino)-N-methylpropionamide], suggesting that the suppression of the large subunit mRNA in the plastids was not mediated through feedback effects of accumulating unassembled large subunits. Coordinate controls at both the mRNA and the translational level require a bidirectional exchange of regulatory signals between chloroplast and cytoplasm. However, these controls were not absolutely restrictive and allowed low rates of uncoupled synthesis of either large or small subunits. Large subunits made in the presence of MDMP were stable over 24 h. However, unassembled small subunits synthesized in 70S-ribosome-deficient leaves were degraded with a half-time of 10.5 h, in contrast to their behavior after integration into the holoprotein in normal leaves, where no turnover was detected. The proteolytic removal of surplus free small subunits is regarded as a final post-translational fine-tuning step to establish a balanced subunit stoichiometry in leaves.


Assuntos
Cloroplastos/enzimologia , Grão Comestível/enzimologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Propionatos/farmacologia , Biossíntese de Proteínas/efeitos dos fármacos , Inibidores da Síntese de Proteínas/farmacologia , RNA Mensageiro/metabolismo , Ribulose-Bifosfato Carboxilase/biossíntese , Secale/enzimologia , Aminoácidos/metabolismo , Sistema Livre de Células , Cloroplastos/efeitos dos fármacos , Cloroplastos/efeitos da radiação , Citoplasma/enzimologia , Eletroforese em Gel de Poliacrilamida , Regulação Enzimológica da Expressão Gênica/efeitos da radiação , Immunoblotting , Luz , Metionina/metabolismo , Peptídeos/genética , Biossíntese de Proteínas/efeitos da radiação , RNA Mensageiro/fisiologia , RNA Ribossômico/fisiologia , Ribulose-Bifosfato Carboxilase/genética , Secale/genética , Transcrição Gênica/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA