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1.
Br J Cancer ; 130(2): 233-241, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-37996507

RESUMO

BACKGROUND: FOLFOXIRI plus bevacizumab has demonstrated benefits for metastatic colorectal cancer (mCRC) patients. However, challenges arise in its clinical implementation due to expected side effects and a lack of stratification criteria. METHODS: The AIO "CHARTA" trial randomised mCRC patients into clinical Group 1 (potentially resectable), 2 (unresectable/risk of rapid progression), or 3 (asymptomatic). They received FOLFOX/bevacizumab +/- irinotecan. The primary endpoint was the 9-month progression-free survival rate (PFSR@9). Secondary endpoints included efficacy in stratified groups, QoL, PFS, OS, ORR, secondary resection rate, and toxicity. RESULTS: The addition of irinotecan to FOLFOX/bevacizumab increased PFSR@9 from 56 to 67%, meeting the primary endpoint. The objective response rate was 61% vs. 69% (P = 0.21) and median PFS was 10.3 vs. 12 months (HR 0.83; P = 0.17). The PFS was (11.4 vs. 12.9 months; HR 0.83; P = 0.46) in potentially resectable patients, with a secondary resection rate of 37% vs. 51%. Moreover, Group 3 (asymptomatic) patients had a PFS of 11.1 vs. 16.1 months (HR 0.6; P = 0.14). The addition of irinotecan did not diminish QoL. CONCLUSION: The CHARTA trial, along with other studies, confirms the efficacy and tolerability of FOLFOXIRI/bevacizumab as a first-line treatment for mCRC. Importantly, clinical stratification may lead to its implementation. TRIAL REGISTRATION: The trial was registered as NCT01321957.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias Colorretais , Humanos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Bevacizumab/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Irinotecano/uso terapêutico , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto
2.
BMC Cancer ; 21(1): 1206, 2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34772353

RESUMO

BACKGROUND: Cytotoxic chemotherapy combinations and targeted agents represent established treatment concepts in advanced pancreatic neuroendocrine tumors (PNETs). However, response rates, side effects and outcome data strongly vary among these therapeutic approaches. Head-to-head comparisons between chemo- and molecular therapies are missing and secondary resistances frequently occur. The RamuNET trial aims to identify the effectiveness of dual treatment with DTIC and ramucirumab in progressive advanced PNET patients. METHODS: The RamuNET study is an investigator-initiated multicenter prospective single-arm trial to evaluate the efficacy of ramucirumab in combination with dacarbazine (DTIC) over a period of at least 6 months. Patients with progressive well-differentiated and metastatic pancreatic neuroendocrine tumors are eligible. The study aims to include 45 patients over a period of 24 months with a minimum follow-up of 24 months. The primary endpoint is disease control after 6 months. Secondary endpoints include progression-free survival, biochemical response, overall survival, quality of life and toxicity. Based on the hypothesis that 80% of the patients can achieve a disease control after 6 months, the sample size calculation follows an exact binomial single-stage design. H0: p < =p0 = 60% versus H1: p > =p1 = 80%, alpha = 0.05, beta = 0.1. DISCUSSION: This study investigates a new therapeutic approach using the combination of cytotoxic and targeted antiangiogenic therapy in advanced PNET. If positive, this trial will be the basis for a randomized two-arm study to investigate the combination of ramucirumab and DTIC against other established therapies in PNET. TRIAL REGISTRATION: EudraCT: 2017-001207-68 . Date of registration: 2018.01.03.


Assuntos
Inibidores da Angiogênese/uso terapêutico , Anticorpos Monoclonais Humanizados/uso terapêutico , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Dacarbazina/uso terapêutico , Tumores Neuroendócrinos/tratamento farmacológico , Neoplasias Pancreáticas/tratamento farmacológico , Adulto , Idoso , Inibidores da Angiogênese/administração & dosagem , Anticorpos Monoclonais Humanizados/administração & dosagem , Antineoplásicos/administração & dosagem , Dacarbazina/administração & dosagem , Humanos , Pessoa de Meia-Idade , Tumores Neuroendócrinos/irrigação sanguínea , Tumores Neuroendócrinos/patologia , Neoplasias Pancreáticas/irrigação sanguínea , Neoplasias Pancreáticas/patologia , Projetos Piloto , Estudos Prospectivos , Fatores de Tempo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Ramucirumab
3.
NEJM Evid ; 3(1): EVIDoa2300172, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38320514

RESUMO

BACKGROUND: Systemic glucocorticoids are commonly used for primary therapy of idiopathic sudden sensorineural hearing loss (ISSNHL). However, the comparative effectiveness and risk profiles of high-dose over lower-dose regimens remain unknown. METHODS: We randomly assigned patients with sudden hearing loss of greater than or equal to 50 dB within 7 days from onset to receive either 5 days of high-dose intravenous prednisolone at 250 mg/d (HD-Pred), 5 days of high-dose oral dexamethasone at 40 mg/d (HD-Dex), or, as a control, 5 days of oral prednisolone (Pred-Control) at 60 mg/d followed by 5 days of tapering doses. The primary outcome was the change in hearing threshold (pure tone average) in the three most affected contiguous frequencies from baseline to day 30. Secondary outcomes included speech understanding, tinnitus, communication competence, quality of life, hypertension, and insulin resistance. RESULTS: A total of 325 patients were randomly assigned. Mean change in 3PTAmost affected hearing threshold from baseline to 30 days was 34.2 dB (95% CI, 28.4 to 40.0) in the HD-Pred group, 41.4 dB (95% CI, 35.6 to 47.2) in the HD-Dex group, and 41.0 dB (95% CI, 35.2 to 46.8) in the Pred-Control group (P=0.09 for analysis of variance). There were more adverse events related to trial medication in the HD-Pred (n=73) and HD-Dex (n=76) groups than in the Pred-Control group (n=46). CONCLUSIONS: Systemic high-dose glucocorticoid therapy was not superior to a lower-dose regimen in patients with ISSNHL, and it was associated with a higher risk of side effects. (Funded by the Federal Ministry of Education and Research [BMBF]; EudraCT number, 2015­002602­36.)


Assuntos
Glucocorticoides , Perda Auditiva Súbita , Adulto , Humanos , Dexametasona , Perda Auditiva Súbita/induzido quimicamente , Prednisona , Resultado do Tratamento
4.
Trials ; 24(1): 258, 2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-37020315

RESUMO

BACKGROUND: Patients with cirrhosis and ascites (and portal hypertension) are at risk of developing acute kidney injury (AKI). Although many etiologies exist, hepatorenal AKI (HRS-AKI) remains a frequent and difficult-to-treat cause, with a very high mortality when left untreated. The standard of care is the use of terlipressin and albumin. This can lead to reversal of AKI, which is associated to survival. Nevertheless, only approximately half of the patients achieve this reversal and even after reversal patients remains at risk for new episodes of HRS-AKI. TIPS is accepted for use in patients with variceal bleeding and refractory ascites, which leads to a reduction in portal pressure. Although preliminary data suggest it may be useful in HRS-AKI, its use in this setting is controversial and caution is recommended given the fact that HRS-AKI is associated to cardiac alterations and acute-on-chronic liver failure (ACLF) which represent relative contraindications for transjugular intrahepatic portosystemic shunt (TIPS). In the last decades, with the new definition of renal failure in patients with cirrhosis, patients are identified at an earlier stage. These patients are less sick and therefore more likely to not have contraindications for TIPS. We hypothesize that TIPS could be superior to the standard of care in patients with HRS-AKI. METHODS: This study is a prospective, multicenter, open, 1:1-randomized, controlled parallel-group trial. The main end-point is to compare the 12-month liver transplant-free survival in patients assigned to TIPS compared to the standard of care (terlipressin and albumin). Secondary end-point include reversal of HRS-AKI, health-related Quality of Life (HrQoL), and incidence of further decompensation among others. Once patients are diagnosed with HRS-AKI, they will be randomized to TIPS or Standard of Care (SOC). TIPS should be placed within 72 h. Until TIPS placement, TIPS patients will be treated with terlipressin and albumin. Once TIPS is placed, terlipressin and albumin should be weaned off according to the attending physician. DISCUSSION: If the trial were to show a survival advantage for patients who undergo TIPS placement, this could be incorporated in routine clinical practice in the management of patients with HRS-AKI. TRIAL REGISTRATION: Clinicaltrials.gov NCT05346393 . Released to the public on 01 April 2022.


Assuntos
Injúria Renal Aguda , Varizes Esofágicas e Gástricas , Síndrome Hepatorrenal , Derivação Portossistêmica Transjugular Intra-Hepática , Humanos , Terlipressina , Síndrome Hepatorrenal/tratamento farmacológico , Síndrome Hepatorrenal/etiologia , Ascite/etiologia , Varizes Esofágicas e Gástricas/complicações , Varizes Esofágicas e Gástricas/tratamento farmacológico , Derivação Portossistêmica Transjugular Intra-Hepática/efeitos adversos , Estudos Prospectivos , Qualidade de Vida , Hemorragia Gastrointestinal , Cirrose Hepática/complicações , Injúria Renal Aguda/etiologia , Albuminas/uso terapêutico
5.
JAMA Oncol ; 7(2): 255-262, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33355646

RESUMO

IMPORTANCE: Pazopanib and gemcitabine have shown good tolerability, albeit modest single-agent activity in pretreated soft tissue sarcoma. A combined regimen to improve outcomes is required. OBJECTIVE: To determine the efficacy of gemcitabine and pazopanib compared with pazopanib alone. DESIGN, SETTING, AND PARTICIPANTS: This multicenter, randomized phase 2 clinical trial was conducted in Germany from September 2011 to July 2014 and included patients with an Eastern Cooperative Oncology Group performance status score of 0 to 2, adequate organ function, measurable lesion, and progression after at least 1 prior treatment with anthracyclines and/or ifosfamide. Data analysis was performed during 2019 and 2020. INTERVENTIONS: Patients were randomized to pazopanib with gemcitabine (A) or without gemcitabine (B). MAIN OUTCOMES AND MEASURES: The primary end point was progression-free survival rate (PFSR) at 12 weeks; secondary end points included toxicity, quality of life, overall survival, and response rates. RESULTS: A total of 90 patients were randomized, and 86 eligible patients (43 women [50%]) were evaluable, with a median age of 57 (range, 22-84) years and Eastern Cooperative Oncology Group performance status score of 0/1 in 77 participants (90%). The predominant histological subtypes were leiomyosarcoma (22 [26%]) and liposarcoma (16 [19%]). After a median follow-up of 12.4 (range, 1-48) months, the primary end point was met, with a PFSR at 12 weeks of 74% (A) vs 47% (B) (hazard ratio [HR], 1.60; 90% CI, 1.15-2.23; P = .01). In the combination arm, PFSR was significantly longer, with a median of 5.6 vs 2.0 months (HR, 0.58; 95% CI, 0.36-0.92; P = .02) compared with single-agent pazopanib, whereas overall survival was similar, with 13.1 vs 11.2 months (HR, 0.98; 95% CI, 0.60-1.58; P = .83). The objective response rate was overall low, with 11% (A) vs 5% (B) (P = .10). The toxicity of the combination of pazopanib and gemcitabine was increased, but it was manageable and mainly hematological. CONCLUSIONS AND RELEVANCE: This phase 2 randomized clinical trial of patients with soft tissue sarcoma found that the addition of gemcitabine to pazopanib was tolerable, and PFSR at 12 weeks was significantly higher compared with pazopanib alone. These results suggest clinical activity of the combination, but they should be confirmed in a phase 3 trial in a more homogeneous population (eg, leiomyosarcoma). TRIAL REGISTRATION: German Clinical Trials Identifier: DRKS00003139.


Assuntos
Ifosfamida , Sarcoma , Adulto , Idoso , Idoso de 80 Anos ou mais , Antraciclinas/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Desoxicitidina/análogos & derivados , Feminino , Humanos , Ifosfamida/efeitos adversos , Indazóis , Pessoa de Meia-Idade , Pirimidinas , Qualidade de Vida , Sarcoma/tratamento farmacológico , Sulfonamidas , Resultado do Tratamento , Adulto Jovem , Gencitabina
6.
J Neurosurg ; 127(6): 1376-1383, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28298021

RESUMO

OBJECTIVE In clinical routines, neuroprotective strategies in neurosurgical interventions are still missing. A pilot study (n = 30) and an analogously performed Phase III trial (n = 112) pointed to a beneficial effect of prophylactic nimodipine and hydroxyethyl starch (HES) in vestibular schwannoma (VS) surgery. Considering the small sample size, the data from both studies were pooled. METHODS The patients in both investigator-initiated studies were assigned to 2 groups. The treatment group (n = 70) received parenteral nimodipine (1-2 mg/hour) and HES (hematocrit 30%-35%) from the day before surgery until the 7th postoperative day. The control group (n = 72) was not treated prophylactically. Facial and cochlear nerve functions were documented preoperatively, during the inpatient care, and 1 year after surgery. RESULTS Pooled raw data were analyzed retrospectively. Intent-to-treat analysis revealed a significantly lower risk for hearing loss (Class D) 12 months after surgery in the treatment group compared with the control group (OR 0.46, 95% CI 0.22-0.97; p = 0.04). After exclusion of patients with preoperative Class D hearing, this effect was more pronounced (OR 0.38, 95% CI 0.17-0.83; p = 0.016). Logistic regression analysis adjusted for tumor size showed a 4 times lower risk for hearing loss in the treatment group compared with the control group (OR 0.25, 95% CI 0.09-0.63; p = 0.003). Facial nerve function was not significantly improved with treatment. Apart from dose-dependent hypotension (p < 0.001), the study medication was well tolerated. CONCLUSIONS Prophylactic nimodipine is safe and may be recommended in VS surgery to preserve hearing. Prophylactic neuroprotective treatment in surgeries in which nerves are at risk seems to be a novel and promising concept. Clinical trial registration no.: DRKS 00000328 ( https://drks-neu.uniklinik-freiburg.de/drks_web/ ).


Assuntos
Perda Auditiva/cirurgia , Neuroma Acústico/cirurgia , Fármacos Neuroprotetores/uso terapêutico , Procedimentos Neurocirúrgicos/métodos , Nimodipina/uso terapêutico , Adulto , Feminino , Audição , Perda Auditiva/tratamento farmacológico , Perda Auditiva/etiologia , Testes Auditivos , Humanos , Masculino , Pessoa de Meia-Idade , Neuroma Acústico/complicações , Neuroma Acústico/tratamento farmacológico , Projetos Piloto , Estudos Retrospectivos , Resultado do Tratamento
7.
J Plant Physiol ; 163(3): 369-81, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16413947

RESUMO

Transient peaks of the cytoplasmic pH are essential elements in a number of signal cascades that activate environmental responses or developmental processes in plant cells but little is known about the mechanisms of their generation. In many plant cells, elicitation of the hypersensitive response is preceded by a perturbation of the ionic balance at the plasma membrane including the inhibition of the proton pump and the influx of H+ from the apoplast. A basically different mechanism of cytoplasmic acidification that is fed by vacuolar protons has been discovered in cell suspensions of the California Poppy (Eschscholzia californica). These cells react to a yeast glycoprotein elicitor with the overproduction of benzophenanthridine alkaloids. Low elicitor concentrations trigger the biosynthesis of these phytoalexins without invoking elements of the hypersensitive response. Accumulated data support the existence of a signal path that includes the following steps: Links between the above events that connect them within a distinct signal path are substantiated by the phenotypes of transformed cell lines that either display lowered Galpha levels due to antisense transformation or express Galpha-binding antibodies in the cytoplasm. All of these cell lines lack the elicitor-activation of PLA2 and of vacuolar proton fluxes and show an impaired phytoalexin response to low elicitor concentrations. High elicitor concentrations trigger alkaloid biosynthesis via an increase of jasmonate at a pH-independent signal path.


Assuntos
Eschscholzia/metabolismo , Transdução de Sinais , Alcaloides/biossíntese , Membrana Celular/química , Citoplasma/química , Eschscholzia/química , Eschscholzia/citologia , Proteínas Fúngicas/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Lisofosfatidilcolinas/metabolismo , Modelos Biológicos , Fosfolipases A/genética , Fosfolipases A/metabolismo , Fosfolipases A2 , Extratos Vegetais/biossíntese , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , ATPases Translocadoras de Prótons/metabolismo , Sesquiterpenos , Trocadores de Sódio-Hidrogênio/fisiologia , Terpenos , Vacúolos/química , Vacúolos/metabolismo , Fitoalexinas
8.
J Neurosurg ; 124(3): 657-64, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26274985

RESUMO

OBJECTIVE: A pilot study of prophylactic nimodipine and hydroxyethyl starch treatment showed a beneficial effect on facial and cochlear nerve preservation following vestibular schwannoma (VS) surgery. A prospective Phase III trial was undertaken to confirm these results. METHODS: An open-label, 2-arm, randomized parallel group and multicenter Phase III trial with blinded expert review was performed and included 112 patients who underwent VS surgery between January 2010 and February 2013 at 7 departments of neurosurgery to investigate the efficacy and safety of the prophylaxis. The surgery was performed after the patients were randomly assigned to one of 2 groups using online randomization. The treatment group (n = 56) received parenteral nimodipine (1-2 mg/hr) and hydroxyethyl starch (hematocrit 30%-35%) from the day before surgery until the 7th postoperative day. The control group (n = 56) was not treated prophylactically. RESULTS: Intent-to-treat analysis showed no statistically significant effects of the treatment on either preservation of facial nerve function (35 [67.3%] of 52 [treatment group] compared with 34 [72.3%] of 47 [control group]) (p = 0.745) or hearing preservation (11 [23.4%] of 47 [treatment group] compared with 15 [31.2%] of 48 [control group]) (p = 0.530) 12 months after surgery. Since tumor sizes were significantly larger in the treatment group than in the control group, logistic regression analysis was required. The risk for deterioration of facial nerve function was adjusted nearly the same in both groups (OR 1.07 [95% CI 0.34-3.43], p = 0.91). In contrast, the risk for postoperative hearing loss was adjusted 2 times lower in the treatment group compared with the control group (OR 0.49 [95% CI 0.18-1.30], p = 0.15). Apart from dose-dependent hypotension (p < 0.001), no clinically relevant adverse reactions were observed. CONCLUSIONS: There were no statistically significant effects of the treatment. Despite the width of the confidence intervals, the odds ratios may suggest but do not prove a clinically relevant effect of the safe study medication on the preservation of cochlear nerve function after VS surgery. Further study is needed before prophylactic nimodipine can be recommended in VS surgery.


Assuntos
Traumatismos dos Nervos Cranianos/prevenção & controle , Neuroma Acústico/cirurgia , Nimodipina/uso terapêutico , Complicações Pós-Operatórias , Vasodilatadores/uso terapêutico , Adulto , Nervo Coclear/fisiopatologia , Traumatismos dos Nervos Cranianos/etiologia , Nervo Facial/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
9.
Trials ; 13: 135, 2012 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-22883020

RESUMO

BACKGROUND: State of the art sedation concepts on intensive care units (ICU) favor propofol for a time period of up to 72 h and midazolam for long-term sedation. However, intravenous sedation is associated with complications such as development of tolerance, insufficient sedation quality, gastrointestinal paralysis, and withdrawal symptoms including cognitive deficits. Therefore, we aimed to investigate whether sevoflurane as a volatile anesthetic technically implemented by the anesthetic-conserving device (ACD) may provide advantages regarding 'weaning time', efficiency, and patient's safety when compared to standard intravenous sedation employing propofol. METHOD/DESIGN: This currently ongoing trial is designed as a two-armed, monocentric, randomized prospective phase II study including intubated intensive care patients with an expected necessity for sedation exceeding 48 h. Patients are randomly assigned to either receive intravenous sedation with propofol or sevoflurane employing the ACD. Primary endpoint is the comparison of the 'weaning time' defined as the time required from discontinuation of the sedating agent until sufficient spontaneous breathing occurs. Moreover, sedation depth evaluated by Richmond Agitation Sedation Scale and parameters of patient's safety (that is, vital signs, laboratory monitoring of organ function) as well as the duration of mechanical ventilation and overall stay on the ICU are analyzed and compared. An intention-to-treat analysis will be carried out with all patients for whom it will be possible to define a wake-up time. In addition, a per-protocol analysis is envisaged. Completion of patient recruitment is expected by the end of 2012. DISCUSSION: This clinical study is designed to evaluate the impact of sevoflurane during long-term sedation of critically ill patients on 'weaning time', efficiency, and patient's safety compared to the standard intravenous sedation concept employing propofol. TRIAL REGISTRATION: EudraCT2007-006087-30; ISRCTN90609144.


Assuntos
Anestésicos Inalatórios/administração & dosagem , Anestésicos Intravenosos/administração & dosagem , Cuidados Críticos/métodos , Hipnóticos e Sedativos/administração & dosagem , Éteres Metílicos/administração & dosagem , Propofol/administração & dosagem , Projetos de Pesquisa , Administração por Inalação , Anestésicos Inalatórios/efeitos adversos , Anestésicos Inalatórios/economia , Anestésicos Intravenosos/efeitos adversos , Anestésicos Intravenosos/economia , Análise Custo-Benefício , Cuidados Críticos/economia , Estado Terminal , Custos de Medicamentos , Alemanha , Custos Hospitalares , Humanos , Hipnóticos e Sedativos/efeitos adversos , Hipnóticos e Sedativos/economia , Infusões Intravenosas , Intubação Intratraqueal , Tempo de Internação , Éteres Metílicos/efeitos adversos , Éteres Metílicos/economia , Monitorização Fisiológica , Propofol/efeitos adversos , Propofol/economia , Estudos Prospectivos , Respiração Artificial , Sevoflurano , Fatores de Tempo , Resultado do Tratamento , Desmame do Respirador , Sinais Vitais
10.
Plant J ; 52(6): 1041-51, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17916111

RESUMO

Plant heterotrimeric G-proteins are involved in a variety of signaling pathways, though only one alpha and a few betagamma isoforms of their subunits exist. In isolated plasma membranes of California poppy (Eschscholzia californica), the plant-specific Galpha subunit was isolated and identified immunologically and by homology of the cloned gene with that of several plants. In the same membrane, phospholipase A(2) (PLA(2)) was activated by yeast elicitor only if GTPgammaS (an activator of Galpha) was present. From the cholate-solubilized membrane proteins, PLA(2) was co-precipitated together with Galpha by a polyclonal antiserum raised against the recombinant Galpha. In this immunoprecipitate and in the plasma membrane (but not in the Galpha-free supernatant) PLA(2) was stimulated by GTPgammaS. Plasma membranes and immunoprecipitates obtained from antisense transformants with a low Galpha content allowed no such stimulation. An antiserum raised against the C-terminus (which in animal Galphas is located near the target coupling site) precipitated Galpha without any PLA(2) activity. Using non-denaturing PAGE, complexes of solubilized plasma membrane proteins were visualized that contained Galpha plus PLA(2) activity and dissociated at pH 9.5. At this pH, PLA(2) was no longer stimulated by GTPgammaS. It is concluded that a distinct fraction of the plasma membrane-bound PLA(2) exists in a detergent-resistant complex with Galpha that can be dissociated at pH 9.5. This complex allows the Galpha-mediated activation of PLA(2).


Assuntos
Membrana Celular/metabolismo , Eschscholzia/metabolismo , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Fosfolipases A2/metabolismo , Proteínas de Plantas/metabolismo , Sequência de Aminoácidos , Eletroforese em Gel de Poliacrilamida , Eschscholzia/genética , Subunidades alfa de Proteínas de Ligação ao GTP/genética , Guanosina 5'-O-(3-Tiotrifosfato)/metabolismo , Guanosina Trifosfato/metabolismo , Concentração de Íons de Hidrogênio , Imunoprecipitação , Dados de Sequência Molecular , Fosfolipases A2/genética , Proteínas de Plantas/genética , Ligação Proteica , Homologia de Sequência de Aminoácidos , Transdução de Sinais
11.
Appl Environ Microbiol ; 68(4): 1524-33, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11916664

RESUMO

On searching for endogenous, low-molecular-weight effectors of benzodiazepine alkaloid biosynthesis in Penicillium cyclopium uric acid was isolated from ethanolic or autoclaved mycelial extracts of this fungus. The isolation was based on a three-step high-pressure liquid chromatography procedure guided by a microplate bioassay, and uric acid was identified by mass spectrometry and the uricase reaction. Conidiospore suspensions that were treated with this compound during the early phase of outgrowth developed emerged cultures with an enhanced rate of alkaloid production. Uric acid treatment did not increase the in vitro measurable activity of the rate-limiting biosynthetic enzyme, cyclopeptine synthetase. However, these cultures displayed a reduced rate of uptake of the alkaloid precursor L-phenylalanine into the vacuoles of the hyphal cells as assayed in situ. It is suggested that the depressed capacity of vacuolar uptake caused by the contact of outgrowing spores with uric acid liberated from hyphal cells results in an enhanced availability of the precursor L-phenylalanine in the cytoplasm and thus accounts at least in part for the increase in alkaloid production.


Assuntos
Antibacterianos/metabolismo , Benzodiazepinonas/metabolismo , Regulação Fúngica da Expressão Gênica , Penicillium/metabolismo , Ácido Úrico/metabolismo , Antibacterianos/química , Benzodiazepinonas/química , Meios de Cultura , Penicillium/crescimento & desenvolvimento , Fenilalanina/metabolismo , Transdução de Sinais , Ácido Úrico/química
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