Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 86
Filtrar
1.
Neurosurg Rev ; 46(1): 25, 2022 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-36574089

RESUMO

The Berlin Grading System assesses clinical severity of moyamoya angiopathy (MMA) by combining MRI, DSA, and cerebrovascular reserve capacity (CVRC). Our aim was to validate this grading system using [15O]H2O PET for CVRC. We retrospectively identified bilateral MMA patients who underwent [15O]H2O PET examination and were treated surgically at our department. Each hemisphere was classified using the Suzuki and Berlin Grading System. Preoperative symptoms and perioperative ischemias were collected, and a logistic regression analysis was performed. A total of 100 hemispheres in 50 MMA patients (36 women, 14 men) were included. Using the Berlin Grading System, 2 (2.8%) of 71 symptomatic hemispheres were categorized as grade I, 14 (19.7%) as grade II, and 55 (77.5%) as grade III. The 29 asymptomatic hemispheres were characterized as grade I in 7 (24.1%) hemispheres, grade II in 12 (41.4%), and grade III in 10 (34.5%) hemispheres. Berlin grades were independent factors for identifying hemispheres as symptomatic and higher grades correlated with increasing proportion of symptomatic hemispheres (p < 0.01). The Suzuki grading did not correlate with preoperative symptoms (p = 0.26). Perioperative ischemic complications occurred in 8 of 88 operated hemispheres. Overall, complications did not occur in any of the grade I hemispheres, but in 9.1% (n = 2 of 22) and 9.8% (n = 6 of 61) of grade II and III hemispheres, respectively. In this study, we validated the Berlin Grading System with the use of [15O]H2O PET for CVRC as it could stratify preoperative symptomatology. Furthermore, we highlighted its relevance for predicting perioperative ischemic complications.


Assuntos
Revascularização Cerebral , Doença de Moyamoya , Masculino , Humanos , Feminino , Estudos Retrospectivos , Doença de Moyamoya/diagnóstico por imagem , Doença de Moyamoya/cirurgia , Imageamento por Ressonância Magnética , Revascularização Cerebral/efeitos adversos , Tomografia por Emissão de Pósitrons
2.
Neurosurg Rev ; 45(6): 3689-3698, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36163319

RESUMO

Moyamoya angiopathy (MMA) can be treated using direct, indirect, or combined revascularization procedures. We perform combined revascularization using the STA-MCA bypass and minimally invasive encephalodurosynangiosis (MIS-EDS). Due to lack of systematic analyses to date it remains unclear whether and to which extent this limited EDS serves as a growth source for extracerebral blood vessels into the brain. The objective of the current study is to characterize the extent of angiographic filling of MIS-EDS and STA-MCA bypass development over time and to determine possible predictors of EDS development in adult MMA patients. Single-center retrospective analysis of 81 MMA patients (139 hemispheres) treated with a MIS-EDS and STA-MCA bypass was performed. Angiographic images and clinical/operative data were reviewed and scored. Uni-/ and multivariate Cox regression analyses identified preoperative predictors of good EDS vascularization. At 3-6 months after surgery EDS showed moderate and high angiographic filling in 40% and 5% of hemispheres, respectively. After 12 months moderate and high filling was found in 57% and 4% of hemispheres, respectively. STA-MCA bypass filling was moderate in 47% and high in 7% of hemispheres at 3-6 months and 45% moderate and 9% high after 12 months. High STA-MCA bypass filling on angiography was a negative predictor of EDS development. MIS-EDS is a simple technique and serves as a source of vessel growth into the brain. EDS development lags behind that of STA-MCA bypass and can be recommended as an additive revascularization source when combined with a direct bypass.


Assuntos
Revascularização Cerebral , Doença de Moyamoya , Adulto , Humanos , Revascularização Cerebral/métodos , Estudos Retrospectivos , Angiografia Cerebral/métodos , Doença de Moyamoya/diagnóstico por imagem , Doença de Moyamoya/cirurgia , Angiografia por Ressonância Magnética , Artérias Temporais/cirurgia , Artéria Cerebral Média/cirurgia
3.
BMC Urol ; 19(1): 96, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31638979

RESUMO

BACKGROUND: Robotic stereotactic ablative radiotherapy (SABR) is currently under investigation as a noninvasive treatment option for patients with renal cell carcinoma (RCC). For radiation therapy of RCC, tumor motion and the need for high ablative doses while preserving the remaining renal parenchyma is a challenge. We aimed to analyze the safety and efficacy of robotic radiosurgery in RCC in a specific difficult subgroup of patients with impaired renal function. METHODS: We retrospectively identified all patients with RCC, treated with robotic SABR and motion compensation in our institution between 2012 and 2017. Either single fraction SABR of 24 or 25 Gy or 3 fractions of 12 Gy prescribed to the 70% isodose line was applied. Local control, overall survival, radiation side effects were evaluated together with renal function and tumor motion. RESULTS: We analyzed data of 13 lesions treated in 10 patients with clear cell RCC and a mean age of 70.5 ± 13.6 years (range: 48-87). Prior to SABR, 8 patients underwent previous complete and/or partial nephrectomy, 7 patients presented with chronic kidney disease ≥ stage 3. The median of minimum, mean and maximum planning target volume doses were 23.2, 29.5 and 35.0 Gy for single fraction and 24.4, 42.5 and 51.4 Gy for the three fractions regime. Persistent local control by robotic SABR was achieved in 9 out of 10 patients (92.3% of all lesions) within a median follow-up period of 27 month (range: 15-54). One patient underwent nephrectomy due to progressive disease and sufficient renal function of the contralateral kidney. Renal function remained stable with a mean estimated glomerular filtration rate (eGFR) of 51.3 ± 19.7 ml/min at baseline and 51.6 ± 25.8 ml/min at follow-up. The largest respiratory-induced tumor motion was seen in superior-inferior direction, compensated by the CyberKnife with mean targeting errors of maximal 2.2 mm. CONCLUSIONS: Robotic SABR is technically feasible for the treatment of RCC in preexisting kidney disease with good local tumor control at about 2 years follow-up. Robotic SABR with motion tracking offers a valid treatment option for patients, who are at increased risk for progression to end-stage renal disease due to partial nephrectomy or ablative techniques.


Assuntos
Carcinoma de Células Renais/complicações , Carcinoma de Células Renais/radioterapia , Neoplasias Renais/complicações , Neoplasias Renais/radioterapia , Radiocirurgia/métodos , Insuficiência Renal/complicações , Procedimentos Cirúrgicos Robóticos , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Radiocirurgia/efeitos adversos , Estudos Retrospectivos , Procedimentos Cirúrgicos Robóticos/efeitos adversos , Resultado do Tratamento
4.
Acta Neurochir (Wien) ; 158(10): 1895-900, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27573349

RESUMO

BACKGROUND: Moyamoya disease (MMD) may be graded based on DSA, the presence of ischemia in MRI and cerebrovascular reserve capacity allowing the prediction of ischemic symptoms in patients. Cerebral ischemia represents a severe complication in revascularization surgery. Focusing on different clinical features of hemodynamic impairment, MMD grading may allow prediction of ischemic complications. It was the aim to analyze whether MMD grading stratifies for ischemic complications in revascularization surgery for MMD. METHOD: In 37 MMD patients a bilateral, standardized, one-staged revascularization approach consisting of STA-MCA bypass/encephalomyosynangiosis (EMS) and single EMS on the contralateral hemisphere was performed. Clinical data including DSA, MRI and rCBF (Xenon-CT) studies were assessed and used for grading MMD. All patients were observed on the ICU for at least 24 h and received CT imaging on the first postoperative day and in case of neurological deterioration. Ischemic complications were analyzed until the day of discharge and at 6-month follow-up. RESULTS: Grading of MMD revealed 11 hemispheres (15 %) as grade I, 33 hemispheres (44 %) as grade II and 30 hemispheres (41 %) as grade III. Eight ischemic complications were observed (11 %). MMD grading demonstrated a significant correlation with ischemic complications: 0 complications in grade I, 3 in grade II (9 %) and 5 in grade III hemispheres (16 %; p < 0.05, Fisher's exact test). CONCLUSIONS: The proposed grading system allows to stratify for ischemic complications in MMD patients that receive bilateral, one-staged revascularization surgery. Future studies will have to investigate its use for predicting ischemic complications in other revascularization strategies for MMD.


Assuntos
Isquemia Encefálica/etiologia , Revascularização Cerebral/efeitos adversos , Doença de Moyamoya/cirurgia , Complicações Pós-Operatórias/etiologia , Adulto , Isquemia Encefálica/diagnóstico por imagem , Angiografia Cerebral , Revascularização Cerebral/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Doença de Moyamoya/diagnóstico por imagem , Complicações Pós-Operatórias/diagnóstico por imagem
5.
J Neurooncol ; 129(1): 33-8, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27188647

RESUMO

The extra domain A (ED A) of fibronectin has been identified as a tumor vessel specific neovascular marker in glioma. Antibody based vascular targeting against ED A of fibronectin allows precise accumulation of photosensitizer in glioma microvasculature and thereby promises to overcome drawbacks of current photodynamic therapy (PDT) for glioma treatment. Our aim was to characterize microcirculatory consequences of F8-small immunoprotein (SIP) mediated PDT by intravital microscopy (IVM) and to analyze the effects on glioma growth. For IVM SF126 glioma cells were implanted into dorsal skinfold-chamber of nude mice. PDT was performed after intravenous injection of photosensitizer (PS)-coupled F8-SIP or PBS (n = 4). IVM was performed before and after PDT for 4 days. Analysis included total and functional (TVD, FVD) vessel densities, perfusion index (PI), microvascular permeability and blood flow rate (Q). To assess tumor growth SF126 glioma cells were implanted subcutaneously. PDT was performed as a single and repetitive treatment after PS-F8-SIP injection (n = 5). Subcutaneous tumors were treated after uncoupled F8-SIP injection as control group (n = 5). PDT induced microvascular stasis and thrombosis with reduced FVD (24 h: 115.98 ± 0.7 vs. 200.8 ± 61.9 cm/cm(2)) and PI (39 ± 11 vs. 70 ± 10 %), whereas TVD was not altered (298 ± 39.2 vs. 278.2 ± 51 cm/cm(2)). Microvascular dysfunction recovered 4 days after treatment. Microvascular dysfunction led to a temporary reduction of glioma growth in the first 48 h after treatment with complete recovery 5 days after treatment. Repetitive PDT resulted in sustained reduction of tumor growth. F8-SIP mediated PDT leads to microvascular dysfunction and reduced glioma growth in a preclinical glioma model with recovery of microcirculation 4 days after treatment. Repetitive application of PDT overcomes microvascular recovery and leads to prolonged antiglioma effects.


Assuntos
Antineoplásicos/administração & dosagem , Neoplasias Encefálicas/tratamento farmacológico , Glioma/tratamento farmacológico , Microvasos/efeitos dos fármacos , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/administração & dosagem , Animais , Antineoplásicos/uso terapêutico , Neoplasias Encefálicas/irrigação sanguínea , Linhagem Celular Tumoral , Glioma/irrigação sanguínea , Humanos , Microscopia Intravital , Camundongos Nus , Fármacos Fotossensibilizantes/uso terapêutico
6.
Eur J Neurol ; 22(6): 1012-7, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25847099

RESUMO

BACKGROUND AND PURPOSE: Occlusive cerebrovascular moyamoya disease (MMD) is rare and has been characterized mainly in Asian countries, so far. In recent years, MMD has been increasingly reported worldwide, raising the question whether its clinical presentation would vary amongst different ethnic backgrounds. Here, a homogeneous series of 153 patients with MMD are reported and the specific clinical features of this rare disease amongst European Caucasians are highlighted. METHODS: A total of 153 European Caucasians with MMD who were treated in our institution between 1997 and 2014 were retrospectively identified. Demographic data, clinical symptoms, angiographic characteristics and functional hemodynamic studies were analyzed. RESULTS: Moyamoya disease presented with a female predominance of 2,9:1.,78% presented with a typical MMD, 17% with a unilateral MMD and 5% with an atypical MMD. 16% of our patients belonged to the pediatric population. Overall, 81% and 8.5% of our cohort presented initially with ischaemic and hemorrhagic manifestation, respectively. The rate of hemorrhagic manifestation of MMD amongst the pediatric group was slightly higher (12%). Angiographic analysis revealed steno-occlusive involvement of the posterior circulation in 34% with a higher involvement in pediatric patients (64%) compared to adults (28%). CONCLUSIONS: The characterization of our homogeneous European Caucasian cohort reveals several significant differences compared to Asian cohorts. In contrast, MMD presents similarly amongst European and North American cohorts, suggesting that non-Asian MMD is characterized by distinct clinical features.


Assuntos
Doença de Moyamoya/etnologia , População Branca/etnologia , Adolescente , Adulto , Criança , Europa (Continente)/etnologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Moyamoya/diagnóstico por imagem , Doença de Moyamoya/fisiopatologia , Radiografia , Estudos Retrospectivos , Fatores Sexuais , Adulto Jovem
7.
Neuroscientist ; 19(5): 434-41, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22968640

RESUMO

Electrical stimulation of the brain was one of the first experimental methods applied to understanding brain organization and function and it continues as a highly useful method both in research and clinical applications. Intracortical microstimulation (ICMS) involves applying electrical stimuli through a microelectrode suitable for recording the action potentials of single neurons. ICMS can be categorized into single-pulse stimulation; high-frequency, short-duration stimulation; and high-frequency, long-duration stimulation. For clinical and experimental reasons, considerable interest focuses on the mechanism of neural activation by electrical stimuli. In this article, we discuss recent results suggesting that action potentials evoked in cortical neurons by high-frequency electrical stimulation do not sum with the natural, behaviorally related background activity; rather, high-frequency stimulation eliminates and replaces natural activity. We refer to this as neural hijacking. We propose that a major component of the mechanism underlying neural hijacking is excitation of axons by ICMS and elimination of natural spikes by antidromic collision with stimulus-driven spikes evoked at high frequency. Evidence also supports neural hijacking as an important mechanism underlying the action of deep brain stimulation in the subthalamic nucleus and its therapeutic effect in treating Parkinson's disease.


Assuntos
Potenciais de Ação/fisiologia , Estimulação Elétrica , Córtex Motor/fisiologia , Neurônios/fisiologia , Animais , Estimulação Elétrica/métodos , Eletromiografia/métodos , Humanos , Rede Nervosa/imunologia , Rede Nervosa/fisiologia
8.
J Clin Invest ; 108(9): 1387-95, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11696584

RESUMO

Intra-acinar cell activation of digestive enzyme zymogens including trypsinogen is generally believed to be an early and critical event in acute pancreatitis. We have found that the phosphatidylinositol 3-kinase inhibitor wortmannin can reduce the intrapancreatic activation of trypsinogen that occurs during two dissimilar experimental models of rodent acute pancreatitis, secretagogue- and duct injection-induced pancreatitis. The severity of both models was also reduced by wortmannin administration. In contrast, the NF-kappa B activation that occurs during the early stages of secretagogue-induced pancreatitis is not altered by administration of wortmannin. Ex vivo, caerulein-induced trypsinogen activation is inhibited by wortmannin and LY294002. However, the cytoskeletal changes induced by caerulein were not affected by wortmannin. Concentrations of caerulein that induced ex vivo trypsinogen activation do not significantly increase phosphatidylinositol-3,4-bisphosphate or phosphatidylinositol 3,4,5-trisphosphate levels or induce phosphorylation of Akt/PKB, suggesting that class I phosphatidylinositol 3-kinases are not involved. The concentration of wortmannin that inhibits trypsinogen activation causes a 75% decrease in phosphatidylinositol 3-phosphate, which is implicated in vesicle trafficking and fusion. We conclude that a wortmannin-inhibitable phosphatidylinositol 3-kinase is necessary for intrapancreatic activation of trypsinogen and regulating the severity of acute pancreatitis. Our observations suggest that phosphatidylinositol 3-kinase inhibition might be of benefit in preventing acute pancreatitis.


Assuntos
Pancreatite/tratamento farmacológico , Fosfatidilinositol 3-Quinases/metabolismo , Fosfatidilinositol 3-Quinases/fisiologia , Tripsinogênio/metabolismo , Doença Aguda , Androstadienos/farmacologia , Animais , Células Cultivadas , Ceruletídeo/metabolismo , Cromonas/farmacologia , Citoesqueleto/metabolismo , Relação Dose-Resposta a Droga , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Lisossomos/metabolismo , Masculino , Camundongos , Morfolinas/farmacologia , NF-kappa B/metabolismo , Necrose , Fosfatos de Fosfatidilinositol/metabolismo , Fosforilação , Ratos , Fatores de Tempo , Wortmanina
9.
Appl Environ Microbiol ; 67(10): 4734-41, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11571179

RESUMO

An anaerobic, H(2)-utilizing bacterium, strain RD-1, was isolated from the highest growth-positive dilution series of a root homogenate prepared from the sea grass Halodule wrightii. Cells of RD-1 were gram-positive, spore-forming, motile rods that were linked by connecting filaments. Acetate was produced in stoichiometries indicative of an acetyl coenzyme A (acetyl-CoA) pathway-dependent metabolism when RD-1 utilized H(2)-CO(2), formate, lactate, or pyruvate. Growth on sugars or ethylene glycol yielded acetate and ethanol as end products. RD-1 grew at the expense of glucose in the presence of low initial concentrations (up to 6% [vol/vol]) of O(2) in the headspace of static, horizontally incubated culture tubes; the concentration of O(2) decreased during growth in such cultures. Peroxidase, NADH oxidase, and superoxide dismutase activities were detected in the cytoplasmic fraction of cells grown in the presence of O(2). In comparison to cultures incubated under strictly anoxic conditions, acetate production decreased, higher amounts of ethanol were produced, and lactate and H(2) became significant end products when RD-1 was grown on glucose in the presence of O(2). Similarly, when RD-1 was grown on fructose in the presence of elevated salt concentrations, lower amounts of acetate and higher amounts of ethanol and H(2) were produced. When the concentration of O(2) in the headspace exceeded 1% (vol/vol), supplemental H(2) was not utilized. The 16S rRNA gene of RD-1 had a 99.7% sequence similarity to that of Clostridium glycolicum DSM 1288(T), an organism characterized as a fermentative anaerobe. Comparative experiments with C. glycolicum DSM 1288(T) demonstrated that it had negligible H(2)- and formate-utilizing capacities. However, carbon monoxide dehydrogenase was detected in both RD-1 and C. glycolicum DSM 1288(T). A 91.4% DNA-DNA hybridization between the genomic DNA of RD-1 and that of C. glycolicum DSM 1288(T) confirmed that RD-1 was a strain of C. glycolicum. These results indicate that (i) RD-1 metabolizes certain substrates via the acetyl-CoA pathway, (ii) RD-1 can tolerate and consume limited amounts of O(2), (iii) oxic conditions favor the production of ethanol, lactate, and H(2) by RD-1, and (iv) the ability of RD-1 to cope with limited amounts of O(2) might contribute to its survival in a habitat subject to daily gradients of photosynthesis-derived O(2).


Assuntos
Acetatos/metabolismo , Clostridium/fisiologia , Raízes de Plantas/microbiologia , Poaceae/microbiologia , Anaerobiose , Clostridium/genética , Clostridium/ultraestrutura , Meios de Cultura , Genes de RNAr , Hidrogênio/metabolismo , Dados de Sequência Molecular , Oxigênio/farmacologia , Filogenia , Água do Mar , Análise de Sequência de DNA
10.
Antimicrob Agents Chemother ; 45(9): 2486-94, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11502519

RESUMO

Little is known to date about the in vitro activity of fluoroquinolones against Borrelia species. Our study aimed at determining the in vitro activities of 15 quinolones against nine isolates of the Borrelia burgdorferi sensu lato complex in addition to one Borrelia valaisiana and one Borrelia bissettii tick isolate. For the determination of MICs, a standardized colorimetric microdilution method was applied. Determination of minimal borreliacidal concentrations providing 100% killing of the final inoculum (MBCs) after 72 h and time-kill experiments were performed by conventional culture in Barbour-Stoenner-Kelly medium in combination with dark-field microscopy. The rank order of potency on a microgram-per-milliliter basis for the substances with in vitro activity against B. burgdorferi was gemifloxacin (MIC at which 90% of the isolates tested are inhibited [MIC(90)], 0.12 microg/ml) > sitafloxacin (MIC(90), 0.5 microg/ml), grepafloxacin (MIC(90), 0.5 microg/ml) > gatifloxacin (MIC(90), 1 microg/ml), sparfloxacin (MIC(90), 1 microg/ml), trovafloxacin (MIC(90), 1 microg/ml) > moxifloxacin (MIC(90), 2 microg/ml), ciprofloxacin (MIC(90), 2 microg/ml) > levofloxacin (MIC(90), 4 microg/ml) > ofloxacin (MIC(90), 8 microg/ml), norfloxacin (MIC(90), 8 microg/ml) > fleroxacin (MIC(90), >16 microg/ml), and pefloxacin (MIC(90), 32 microg/ml) > nalidixic acid (MIC(90), 256 microg/ml). After 72 h of exposure, gemifloxacin was borreliacidal (100% killing) against the isolates investigated at a median MBC of 4 microg/ml. In the other compounds tested, median MBCs were higher (> or =8 microg/ml). Results of electron microscopy and time-kill studies clearly support an in vitro activity of some fluoroquinolones against borreliae. Our study demonstrates for the first time the enhanced in vitro effectiveness of some of the recently introduced 4-quinolones against B. burgdorferi.


Assuntos
Anti-Infecciosos/farmacologia , Grupo Borrelia Burgdorferi/efeitos dos fármacos , Fluoroquinolonas , Grupo Borrelia Burgdorferi/ultraestrutura , Ceftriaxona/farmacologia , Cefalosporinas/farmacologia , Gemifloxacina , Humanos , Testes de Sensibilidade Microbiana , Microscopia Eletrônica , Naftiridinas/farmacologia , Fatores de Tempo
11.
J Bacteriol ; 183(17): 5134-44, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11489867

RESUMO

Two monofunctional NiFeS carbon monoxide (CO) dehydrogenases, designated CODH I and CODH II, were purified to homogeneity from the anaerobic CO-utilizing eubacterium Carboxydothermus hydrogenoformans. Both enzymes differ in their subunit molecular masses, N-terminal sequences, peptide maps, and immunological reactivities. Immunogold labeling of ultrathin sections revealed both CODHs in association with the inner aspect of the cytoplasmic membrane. Both enzymes catalyze the reaction CO + H(2)O --> CO(2) + 2 e(-) + 2 H(+). Oxidized viologen dyes are effective electron acceptors. The specific enzyme activities were 15,756 (CODH I) and 13,828 (CODH II) micromol of CO oxidized min(-1) mg(-1) of protein (methyl viologen, pH 8.0, 70 degrees C). The two enzymes oxidize CO very efficiently, as indicated by k(cat)/K(m) values at 70 degrees C of 1.3. 10(9) M(-1) CO s(-1) (CODH I) and 1.7. 10(9) M(-1) CO s(-1) (CODH II). The apparent K(m) values at pH 8.0 and 70 degrees C are 30 and 18 microM CO for CODH I and CODH II, respectively. Acetyl coenzyme A synthase activity is not associated with the enzymes. CODH I (125 kDa, 62.5-kDa subunit) and CODH II (129 kDa, 64.5-kDa subunit) are homodimers containing 1.3 to 1.4 and 1.7 atoms of Ni, 20 to 22 and 20 to 24 atoms of Fe, and 22 and 19 atoms of acid-labile sulfur, respectively. Electron paramagnetic resonance (EPR) spectroscopy revealed signals indicative of [4Fe-4S] clusters. Ni was EPR silent under any conditions tested. It is proposed that CODH I is involved in energy generation and that CODH II serves in anabolic functions.


Assuntos
Aldeído Oxirredutases/isolamento & purificação , Bacillaceae/enzimologia , Monóxido de Carbono/metabolismo , Complexos Multienzimáticos/isolamento & purificação , Acetato-CoA Ligase/metabolismo , Aldeído Oxirredutases/química , Aldeído Oxirredutases/genética , Sequência de Aminoácidos , Anaerobiose , Bacillaceae/metabolismo , Dimerização , Espectroscopia de Ressonância de Spin Eletrônica , Eletroforese em Gel de Poliacrilamida , Proteínas Ferro-Enxofre/metabolismo , Cinética , Microscopia Imunoeletrônica , Peso Molecular , Complexos Multienzimáticos/química , Complexos Multienzimáticos/genética
12.
Int J Syst Evol Microbiol ; 51(Pt 3): 1119-1125, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11411680

RESUMO

An anaerobic, acid-tolerant bacterium, CK55T, was isolated from an acidic forest bog. Cells of CK55T stained Gram-negative but did not have an outer membrane. Cells were spore-forming, motile rods with peritrichous flagella, formed chains or aggregates and were linked by connecting filaments that were composed of a core and outer sheath. Cellobiose, glucose, xylose, mannose, mannitol, sucrose and peptone supported growth. Arabinose, lactose, raffinose, H2/CO2, CO/CO2, vanillate, Casamino acids and various purines and pyrimidines did not support growth. Growth on carbohydrates yielded acetate, butyrate, lactate, formate and H2 as end-products. Growth was observed at pH 4.0-9.0, with an optimum at pH 6.5, and at 10-30 degrees C, with an optimum at 20-25 degrees C. At 20 degrees C, doubling times were 4 and 6 h at pH 6.5 and 4.0, respectively. Hydrogenase activity in cell-free extracts was 12 U (mg protein)-1. CK55T did not: (i) contain detectable levels of CO, formate, lactate dehydrogenases or cytochromes; (ii) carry out dissimilatory reduction of nitrate or sulfate; or (iii) produce methane. Thus, CK55T was characterized as a non-acetogenic, fermentative chemo-organotroph. The G+C content of CK55T was 28.0 mol%. CK55T was phylogenetically most closely related to Clostridium botulinum (types B, E and F), Clostridium acetobutylicum and other saccharolytic clostridia; the 16S rRNA gene sequence similarity values to the nearest relatives of CK55T were approximately 97%. Based on morphological, physiological and phylogenetic properties of CK55T, it is proposed that CK55T be termed Clostridium uliginosum sp. nov. (= DSM 12992T = ATCC BAA-53T).


Assuntos
Clostridium/classificação , Filogenia , Anaerobiose , Sequência de Bases , Metabolismo dos Carboidratos , Clostridium/genética , Clostridium/fisiologia , Clostridium/ultraestrutura , DNA Ribossômico/genética , Enzimas/análise , Microscopia Eletrônica , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , Microbiologia do Solo
13.
Gastroenterology ; 120(7): 1818-27, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11375962

RESUMO

BACKGROUND & AIMS: The present study was undertaken to evaluate the role of serine proteases in regulating digestive enzyme secretion in pancreatic acinar cells. METHODS: Isolated acini were stimulated by various secretagogues in the presence or absence of cell-permeant serine protease inhibitors 4-(2-aminoethyl)-benzenesulfonyl fluoride and N(alpha)-p-tosyl-L-phenylalanine chloromethyl ketone. F-actin distribution was studied after staining with rhodamine phalloidin. RESULTS: Both cell-permeant serine protease inhibitors blocked amylase secretion in response to secretagogues that use calcium as a second messenger (e.g., cerulein, carbamylcholine, and bombesin) but not to those that use adenosine 3',5'-cyclic monophosphate (cAMP) as a second messenger (e.g., secretin and vasoactive intestinal polypeptide). Incubation of the acini with these inhibitors also resulted in a dramatic redistribution of the F-actin cytoskeleton. This redistribution was energy dependent. Similar redistribution of F-actin from the apical to the basolateral region was also observed when acini were incubated with a supramaximally stimulating concentration of cerulein, which is known to inhibit secretion. CONCLUSIONS: These results suggest that a serine protease activity is essential for maintaining the normal apical F-actin distribution; its inhibition redistributes F-actin from the apical to the basolateral region and blocks secretion induced by secretagogues that act via calcium. cAMP reverses the F-actin redistribution and hence cAMP-mediated secretion is not affected.


Assuntos
Actinas/metabolismo , Cálcio/fisiologia , Pâncreas/efeitos dos fármacos , Inibidores de Serina Proteinase/farmacologia , Sulfonas/farmacologia , Trifosfato de Adenosina/fisiologia , Animais , Bucladesina/farmacologia , Calcineurina/metabolismo , Calpaína/metabolismo , Ceruletídeo/farmacologia , AMP Cíclico/fisiologia , Masculino , Pâncreas/enzimologia , Pâncreas/ultraestrutura , Proteína Quinase C/metabolismo , Ratos , Ratos Wistar
14.
J Biol Chem ; 276(22): 18742-7, 2001 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-11278554

RESUMO

Prior stress ameliorates caerulein-induced pancreatitis in rats. NF-kappaB is a proinflammatory transcription factor activated during caerulein pancreatitis. However, the effects of prior stress on pancreatic NF-kappaB activation are unknown. In the current study, the effect of prior water immersion stress on caerulein and tumor necrosis factor-alpha (TNF-alpha)-induced NF-kappaB activation in the pancreas was evaluated. Water immersion of rats for up to 6 h prevents supramaximal caerulein-induced pancreatic IkappaB-alpha degradation and NF-kappaB activation in vivo. NF-kappaB activity is also inhibited in vitro in pancreatic acini prepared from water-immersed animals. TNF-alpha-induced NF-kappaB activation in pancreas or in pancreatic acini is unaffected by prior water immersion. Chelation of intracellular Ca(2+) by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetate/acetoxymethyl ester has similar effects to water immersion in preventing caerulein but not TNF-alpha-induced NF-kappaB activation in pancreas. Both the spike response and the sustained rise in [Ca(2+)](i) in response to supramaximal caerulein stimulation are reduced markedly in acini prepared from water-immersed animals as compared with normal animals. Our findings indicate that, in addition to Ca(2+)-dependent mechanisms, Ca(2+)-independent signaling events also may lead to NF-kappaB activation in pancreatic acinar cells. Water immersion stress prevents supramaximal caerulein-induced NF-kappaB activation in pancreas in vivo and in vitro by affecting intracellular Ca(2+) homeostasis.


Assuntos
Cálcio/metabolismo , Ceruletídeo/metabolismo , Proteínas I-kappa B , NF-kappa B/metabolismo , Pâncreas/metabolismo , Água/metabolismo , Animais , Western Blotting , Quelantes/farmacologia , Citoplasma/metabolismo , Proteínas de Ligação a DNA/metabolismo , Eletroforese em Gel de Poliacrilamida , Masculino , Inibidor de NF-kappaB alfa , Ratos , Ratos Wistar , Transdução de Sinais , Estresse Fisiológico , Fatores de Tempo , Fator de Necrose Tumoral alfa/metabolismo
15.
Immunobiology ; 201(3-4): 406-19, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10776796

RESUMO

A growth inhibition assay (GIA) and an immunofluorescence test detecting deposited complement components C6 and C9 were compared for their ability to classify Borrelia isolates with respect to their resistance to non-immune human serum (NHS). In both assays a total of 34 Borrelia isolates of all three human pathogenic genospecies were tested. Interestingly, 95% of the serum-sensitive or intermediate serum-sensitive isolates belonged to the genospecies B. burgdorferi s. s. and B. garinii, whereas most B. afzelii isolates (83%) proved serum-resistant. Consequently, a strong correlation between the assignment of the isolates to the different genospecies and their degree of serum sensitivity was seen. These findings were supported strongly by the quantitative analysis of the deposited complement components and the location of the terminal complement complex on the bacterial surface as detected by means of immunoelectron microscopy. The GIA displayed an obvious lack of sensitivity to slow growing isolates, whereas the IFA allowed classification of all Borrelia isolates. Discrimination between serum-sensitive and serum-resistant isolates in the IFA was the most specific provided that the detection of C6 and C9 was incorporated into the final classification of isolates. Accordingly, both assays, turned out to be effective and reliable tools for the investigation of borrelial serum sensitivity. The IFA, however, is regarded as superior to the GIA owing to the obvious ease of performance and its rapid capability for the classification of even very slow growing isolates.


Assuntos
Grupo Borrelia Burgdorferi/imunologia , Complemento C6/imunologia , Complemento C9/imunologia , Complexo de Ataque à Membrana do Sistema Complemento/imunologia , Grupo Borrelia Burgdorferi/crescimento & desenvolvimento , Grupo Borrelia Burgdorferi/isolamento & purificação , Grupo Borrelia Burgdorferi/ultraestrutura , Humanos , Microscopia Imunoeletrônica/métodos
16.
Int J Syst Evol Microbiol ; 50 Pt 2: 537-546, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10758858

RESUMO

A strictly anaerobic, H2-utilizing bacterium, strain SL1, was isolated from the sediment of an acidic coal mine pond. Cells of strain SL1 were sporulating, motile, long rods with a multilayer cell wall. Growth was observed at 5-35 degrees C and pH 3.9-7.0. Acetate was the sole end product of H2 utilization and was produced in stoichiometries indicative of an acetyl-CoA-pathway-dependent metabolism. Growth and substrate utilization also occurred with CO/CO2, vanillate, syringate, ferulate, ethanol, propanol, 1-butanol, glycerine, cellobiose, glucose, fructose, mannose, xylose, formate, lactate, pyruvate and gluconate. With most substrates, acetate was the main or sole product formed. Growth in the presence of H2/CO2 or CO/CO2 was difficult to maintain in laboratory cultures. Methoxyl, carboxyl and acrylate groups of various aromatic compounds were O-demethylated, decarboxylated and reduced, respectively. Small amounts of butyrate were produced during the fermentation of sugars. The acrylate group of ferulate was reduced. Nitrate, sulfate, thiosulfate, dimethylsulfoxide and Fe(III) were not utilized as electron acceptors. Analysis of the 16S rRNA gene sequence of strain SL1 demonstrated that it is closely related to Clostridium scatologenes (99.6% sequence similarity), an organism characterized as a fermentative anaerobe but not previously shown to be capable of acetogenic growth. Comparative experiments with C. scatologenes DSM 757T demonstrated that it utilized H2/CO2 (negligible growth), CO/CO2 (negligible growth), formate, ethanol and aromatic compounds according to stoichiometries indicative of the acetyl-CoA pathway. CO dehydrogenase, formate dehydrogenase and hydrogenase activities were present in both strain SL1 and C. scatologenes DSM 757T. These results indicate that (i) sediments of acidic coal mine ponds harbour acetogens and (ii) C. scatologenes is an acetogen that tends to lose its capacity to grow acetogenically under H2/CO2 or CO/CO2 after prolonged laboratory cultivation.


Assuntos
Acetatos/metabolismo , Clostridium/classificação , Sedimentos Geológicos/microbiologia , Microbiologia da Água , Aldeído Oxirredutases/metabolismo , Composição de Bases , Monóxido de Carbono/metabolismo , Clostridium/citologia , Clostridium/isolamento & purificação , Clostridium/fisiologia , Meios de Cultura , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Fermentação , Genes de RNAr , Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Complexos Multienzimáticos/metabolismo , Oxirredução , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
17.
Int J Syst Evol Microbiol ; 50 Pt 2: 873-881, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10758899

RESUMO

Two anaerobic acid-tolerant bacteria, CK58T and CK74T, were isolated from acidic beech litter and acidic peat-bog soil, respectively. Both bacteria were spore-forming, motile rods with peritrichous flagella. The capacity to sporulate decreased with prolonged cultivation. Cells of CK58T formed chains or aggregates and were linked by a connecting filament that consisted of a core and a surrounding sheath. Cellobiose, glucose, xylose, arabinose, maltose, mannose and salicin supported growth of CK58T. These substrates, as well as mannitol, lactose, sucrose, glycerol, melezitose, raffinose and rhamnose, supported growth of CK74T. Sorbitol, trehalose, H2/CO2, CO/CO2, vanillate, Casamino acids, peptone, and various purines and pyrimidines did not support the growth of either organism. Growth of CK58T and CK74T on glucose yielded butyrate, lactate, acetate, formate, H2 and CO2 as end products. Growth of CK58T and CK74T was observed at pH 3.7-7.1 and 3.6-6.9, respectively. CK58T and CK74T grew in nitrogen-free medium at pH 3.7 under an N2 atmosphere and reduced acetylene at rates approximating 1 nmol min-1 (mg protein)-1. CK58T and CK74T did not contain carbon monoxide dehydrogenase or cytochromes, produce methane, or dissimilate nitrate or sulfate. Thus, CK58T and CK74T were characterized as nonacetogenic, N2-fixing, fermentative chemo-organotrophs. The G + C contents of CK58T and CK74T were 31.4 and 30.7 mol%, respectively. CK58T and CK74T were phylogenetically most closely related to Clostridium pasteurianum. The 16S rRNA gene sequence similarity values of CK58T and CK74T to C. pasteurianum and each other did not exceed 96.5%, and it is proposed that strains CK58T and CK74T be named Clostridium akagii CK58T (DSM 12554T) and Clostridium acidisoli CK74T (DSM 12555T), respectively. These results suggest that previously uncharacterized clostridial species reside and might fix N2 in the annoxic microzones of acidic forest soil and litter.


Assuntos
Clostridium/classificação , Clostridium/fisiologia , Fixação de Nitrogênio , Microbiologia do Solo , Anaerobiose , Clostridium/isolamento & purificação , Clostridium/ultraestrutura , DNA Bacteriano/genética , DNA Ribossômico/genética , Genes de RNAr , Concentração de Íons de Hidrogênio , Microscopia Eletrônica , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Árvores
18.
Appl Environ Microbiol ; 65(11): 5124-33, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10543831

RESUMO

A thermophilic, fermentative microaerophile (ET-5b) and a thermophilic acetogen (ET-5a) were coisolated from oxic soil obtained from Egypt. The 16S rRNA gene sequence of ET-5a was 99.8% similar to that of the classic acetogen Moorella thermoacetica. Further analyses confirmed that ET-5a was a new strain of M. thermoacetica. For ET-5b, the nearest 16S rRNA gene sequence similarity value to known genera was approximately 88%. ET-5b was found to be a motile rod with a genomic G+C content of 50.3 mol%. Cells were weakly gram positive and lacked spores. Growth was optimal at 55 to 60 degrees C and pH 6.5 to 7.0. ET-5b grew under both oxic and anoxic conditions, but growth was erratic under atmospheric concentrations of O(2). Utilizable substrates included oligosaccharides and monosaccharides. Acetate, formate, and succinate supported growth only under oxic conditions. Saccharides yielded succinate, lactate, ethanol, acetate, formate, and H(2) under anoxic conditions; fermentation products were also formed under oxic conditions. A new genus is proposed, the type strain being Thermicanus aegyptius ET-5b gen. nov., sp. nov. (DSMZ 12793). M. thermoacetica ET-5a (DSMZ 12797) grew commensally with T. aegyptius ET-5b on oligosaccharides via the interspecies transfer of H(2) formate, and lactate. In support of this interaction, uptake hydrogenase and formate dehydrogenase specific activities were fundamentally greater in M. thermoacetica ET-5a than in T. aegyptius ET-5b. These results demonstrate that (i) soils subject to high temperatures harbor uncharacterized thermophilic microaerophiles, (ii) the classic acetogen M. thermoacetica resides in such soils, and (iii) trophic links between such soil bacteria might contribute to their in situ activities.


Assuntos
Bactérias Gram-Positivas/classificação , Bactérias Gram-Positivas/crescimento & desenvolvimento , Microbiologia do Solo , Aerobiose , Anaerobiose , Celobiose/metabolismo , DNA Ribossômico/genética , Egito , Fermentação , Genes Bacterianos , Bactérias Gram-Positivas/ultraestrutura , Temperatura Alta , Microscopia Eletrônica , Filogenia , RNA Bacteriano/genética , RNA Ribossômico 16S/genética
19.
Appl Environ Microbiol ; 65(8): 3633-40, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10427060

RESUMO

To evaluate the microbial populations involved in the reduction of Fe(III) in an acidic, iron-rich sediment, the anaerobic flow of supplemental carbon and reductant was evaluated in sediment microcosms at the in situ temperature of 12 degrees C. Supplemental glucose and cellobiose stimulated the formation of Fe(II); 42 and 21% of the reducing equivalents that were theoretically obtained from glucose and cellobiose, respectively, were recovered in Fe(II). Likewise, supplemental H(2) was consumed by acidic sediments and yielded additional amounts of Fe(II) in a ratio of approximately 1:2. In contrast, supplemental lactate did not stimulate the formation of Fe(II). Supplemental acetate was not consumed and inhibited the formation of Fe(II). Most-probable-number estimates demonstrated that glucose-utilizing acidophilic Fe(III)-reducing bacteria approximated to 1% of the total direct counts of 4', 6-diamidino-2-phenylindole-stained bacteria. From the highest growth-positive dilution of the most-probable-number series at pH 2. 3 supplemented with glucose, an isolate, JF-5, that could dissimilate Fe(III) was obtained. JF-5 was an acidophilic, gram-negative, facultative anaerobe that completely oxidized the following substrates via the dissimilation of Fe(III): glucose, fructose, xylose, ethanol, glycerol, malate, glutamate, fumarate, citrate, succinate, and H(2). Growth and the reduction of Fe(III) did not occur in the presence of acetate. Cells of JF-5 grown under Fe(III)-reducing conditions formed blebs, i.e., protrusions that were still in contact with the cytoplasmic membrane. Analysis of the 16S rRNA gene sequence of JF-5 demonstrated that it was closely related to an Australian isolate of Acidiphilium cryptum (99.6% sequence similarity), an organism not previously shown to couple the complete oxidation of sugars to the reduction of Fe(III). These collective results indicate that the in situ reduction of Fe(III) in acidic sediments can be mediated by heterotrophic Acidiphilium species that are capable of coupling the reduction of Fe(III) to the complete oxidation of a large variety of substrates including glucose and H(2).


Assuntos
Acetobacteraceae/isolamento & purificação , Acetobacteraceae/metabolismo , Sedimentos Geológicos/microbiologia , Ferro/metabolismo , Acetobacteraceae/genética , Composição de Bases , Celobiose/metabolismo , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Ecossistema , Transporte de Elétrons , Genes Bacterianos , Glucose/metabolismo , Microscopia Eletrônica , Dados de Sequência Molecular , Oxirredução , Filogenia , RNA Bacteriano/genética , RNA Ribossômico 16S/genética
20.
Health Soc Work ; 24(2): 112-9, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10340161

RESUMO

The study discussed in this article examined the relationship between the degree of involvement with clients with severe mental illness and social workers' job satisfaction and burnout. A total of 128 social workers were administered a questionnaire that included three scales: an involvement scale, a job satisfaction measure, and the Maslach Burnout Inventory. Greater involvement was related significantly to higher levels of emotional exhaustion and depersonalization. Overall, results suggest that social workers are affected negatively by this type of work. The implications for the social work profession are discussed as well as the importance of social support systems at the work setting that will help social workers cope more effectively with stressful work situations.


Assuntos
Atitude do Pessoal de Saúde , Esgotamento Profissional , Serviços Comunitários de Saúde Mental , Relações Profissional-Paciente , Serviço Social , Adulto , Análise de Variância , Feminino , Humanos , Satisfação no Emprego , Masculino , Pessoa de Meia-Idade , New York , Análise de Regressão , Inquéritos e Questionários
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA