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1.
J Infect ; 84(2): 227-236, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34838593

RESUMO

BACKGROUND: Cerebral aspergillosis (CA) is a life-threatening disease for which diagnosis and management remain challenging. Detailed analyses from large cohorts are lacking. METHODS: We included 119 cases of proven (n = 54) or probable (n = 65) CA diagnosed between 2006 and 2018 at 20 French hospitals. Data were collected at baseline and during follow-up. Cerebral imaging was reviewed centrally by two neuroradiologists. RESULTS: The most frequent underlying conditions were hematological malignancy (40%) and solid organ transplantation (29%). Galactomannan was detected in the serum of 64% of patients. In 75% of cases, at least one of galactomannan, Aspergillus PCR, and ß-d-glucan was positive in the cerebrospinal fluid. Six-week mortality was 45%. Two distinct patterns of disease were identified according to presumed route of dissemination. Presumed haematogenous dissemination (n = 88) was associated with a higher frequency of impaired consciousness (64%), shorter time to diagnosis, the presence of multiple abscesses (70%), microangiopathy (52%), detection of serum galactomannan (69%) and Aspergillus PCR (68%), and higher six-week mortality (54%). By contrast, contiguous dissemination from the paranasal sinuses (n = 31) was associated with a higher frequency of cranial nerve palsy (65%), evidence of meningitis on cerebral imaging (83%), macrovascular lesions (61%), delayed diagnosis, and lower six-week mortality (30%). In multivariate analysis and in a risk prediction model, haematogenous dissemination, hematological malignancy and the detection of serum galactomannan were associated with higher six-week mortality. CONCLUSION: Distinguishing between hematogenous and contiguous dissemination patterns appears to be critical in the workup for CA, as they are associated with significant differences in clinical presentation and outcome.


Assuntos
Antifúngicos , Aspergilose , Antifúngicos/uso terapêutico , Aspergilose/diagnóstico , Aspergillus , Estudos de Coortes , Grão Comestível/química , Humanos , Mananas/análise
2.
Rev Med Interne ; 38(5): 320-327, 2017 May.
Artigo em Francês | MEDLINE | ID: mdl-27639910

RESUMO

Opportunistic infections (OI) are uncommon in sarcoidosis (1 to 10%) and mostly occur in patients with previously diagnosed disease or can rarely be the presenting manifestation. The most common OIs are, in descending order: aspergillosis, cryptococcosis, and mycobacterial infections. Treatment with corticosteroids is the most frequent risk factor for OI occurrence during sarcoidosis but immunosuppressive drugs and therapy with anti-TNFα are also risk factors. Overall, clinical presentation, treatment, and outcome are identical to that occur in other conditions complicated with the occurrence of OIs. However, some atypical presentations of OIs can mimic sarcoidosis exacerbation and misdiagnosis may lead clinicians to increase immunosuppression, causing worsening of the OI. The meticulous collection of patient's history along with factors differentiating OI from sarcoidosis exacerbation is key factor to optimally manage these patients.


Assuntos
Infecções Oportunistas/etiologia , Sarcoidose/complicações , Aspergilose/etiologia , Criptococose/etiologia , Humanos , Hospedeiro Imunocomprometido , Infecções por Mycobacterium/etiologia , Micoses/etiologia , Infecções Oportunistas/imunologia , Infecções Oportunistas/terapia , Doenças Raras/etiologia , Fatores de Risco , Sarcoidose/imunologia , Sarcoidose/terapia , Viroses/etiologia
3.
Med Mal Infect ; 43(4): 139-45, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23562488

RESUMO

Azole resistance has appeared recently in Aspergillus fumigatus and increased dangerously in the last decade. The main resistance mechanism is a point mutation of CYP51A, the gene encoding 14α-sterol demethylase, the target enzyme of azole antifungal drugs. This mutation can induce resistance to itraconazole alone or multi-azole resistance. CYP51A mutation can occur in two cases. The first usually concerns patients receiving long-term azole therapy, most of the time for chronic aspergillosis, and involves a wide range of mutations. The second is due to the use of azole fungicides in agriculture. The latter favors a single mutagenesis event: a substitution of leucine for histidine at codon 98 and the tandem repeat of a 34-base pair tandem sequence in the CYP51A gene promoter region. This confers cross-resistance to all azole antifungal drugs. This emerging and environmentally linked issue is of growing concern for the management of antifungal therapy. This mechanism of resistance was first described in the Netherlands and is now reported worldwide. It may have become the leading mechanism of azole resistance in A. fumigatus. Azoles are major agents for the treatment of aspergillosis, and the only oral antifungals. Infection with antifungal-resistant strains is correlated with treatment failure. This emerging phenomenon stresses the urgent need for new preventive strategies (controlled use of antifungals and azole prophylaxis), new diagnostic strategies (early detection of resistance), and new therapeutic strategies in the management of A. fumigatus infections.


Assuntos
Antifúngicos/farmacologia , Aspergilose/microbiologia , Aspergillus fumigatus/efeitos dos fármacos , Farmacorresistência Fúngica Múltipla , Triazóis/farmacologia , Agroquímicos/farmacologia , Antifúngicos/uso terapêutico , Aspergilose/tratamento farmacológico , Aspergilose/epidemiologia , Aspergilose/prevenção & controle , Aspergillus fumigatus/genética , Sistema Enzimático do Citocromo P-450/genética , Farmacorresistência Fúngica Múltipla/genética , Microbiologia Ambiental , Previsões , Proteínas Fúngicas/genética , Fungicidas Industriais/farmacologia , Saúde Global , Humanos , Testes de Sensibilidade Microbiana , Mutagênese , Mutação Puntual , Regiões Promotoras Genéticas/genética , Sequências de Repetição em Tandem , Triazóis/uso terapêutico
4.
Eur J Surg Oncol ; 33(4): 498-503, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17156969

RESUMO

AIM: To report the outcome of 30 patients who underwent surgery after concomitant chemoradiation for locally advanced cervical cancer with residual disease > or = 2 cm. METHODS: From 1988 to 2004, 143 patients with FIGO stage IB2-IVA cervical cancer underwent surgery after concurrent chemoradiotherapy. Among them, 30 had a residual cervical tumour > or = 2 cm prior to surgery. Surgery consisted in a simple or radical hysterectomy (n=15) or in a pelvic exenteration (n=15). Endpoints were recurrence and distant metastasis rates, overall survival (OS) and disease-free survival (DFS) at 3 and 5 years. Analysis included FIGO stage, response to chemoradiation, para-aortic lymphatic status or type of surgery: palliative (remaining disease after surgery) or curative (no evidence of remaining disease after surgery). RESULTS: Surgery has been only palliative in 11 cases. Pelvic recurrences occurred in 8 patients after a median interval of 8.8 months. Distant metastases occurred in 8 patients after a median interval of 13 months. So far, 16 patients have died (53.3%). The 3-year and 5-year OS rates are 64.9% and 55.6%, respectively, for the 19 patients who had a curative surgery. The DFS rate is 50.8% at 3 and 5 years in this latter group. Overall 12 patients (40%) are alive and free of disease after a median follow-up of 32.5 months. CONCLUSIONS: Adjuvant surgery may improve the outcome of patients with bulky residual tumour after chemoradiation for locally advanced cervical cancer, allowing a 5-year OS of 55.6% after curative intervention.


Assuntos
Neoplasia Residual/cirurgia , Neoplasias do Colo do Útero/cirurgia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Distribuição de Qui-Quadrado , Terapia Combinada , Feminino , Humanos , Histerectomia , Modelos Logísticos , Metástase Linfática , Pessoa de Meia-Idade , Metástase Neoplásica , Estadiamento de Neoplasias , Neoplasia Residual/tratamento farmacológico , Neoplasia Residual/radioterapia , Resultado do Tratamento , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/radioterapia
5.
Cancer Radiother ; 10(6-7): 471-6, 2006 Nov.
Artigo em Francês | MEDLINE | ID: mdl-16931091

RESUMO

Standard treatment of locally advanced cervical carcinoma is actually represented by concomitant chemoradiotherapy followed by brachytherapy since several randomised study results in 1999. Surgical resection after concomitant chemoradiotherapy for locally advanced cervical carcinoma is discussed without evidence of benefice on survival and because morbidity. The aim of this study is to discuss surgery after chemoradiotherapy in terms of rate of morbidity and residual tumor, rate of pelvic disease control, overall survival and disease-free survival.


Assuntos
Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/cirurgia , Braquiterapia , Terapia Combinada , Intervalo Livre de Doença , Feminino , Humanos , Estadiamento de Neoplasias , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/radioterapia
6.
Ann Chir ; 131(8): 431-6, 2006 Oct.
Artigo em Francês | MEDLINE | ID: mdl-16707093

RESUMO

PURPOSE: The aim of this study is to show that the removal of the rectum is not an obstacle to implement an optimal surgery in advanced epithelial cancer of the ovary. MATERIAL AND METHODS: Retrospective study on a population of 44 women with advanced epithelial cancer of the ovary. The surgery was realized between January 95 and July 03, and all surgeries required a posterior exenteration. This treatment was completed by chemotherapy for 36 of them. RESULTS: The median survival of this population is 36.6 months. 6/44 patients (13.6%) had post-operative complications. The completion of chemotherapy started after an average of 5.2 weeks after surgery. All the assessable patients (43/44) have an anal satisfactory continence. CONCLUSION: The posterior exenteration, when it's necessary, for advanced epithelial cancer of the ovary must not be an obstacle to obtain an optimal surgery. Anal continence is respected and there are no more complications. This surgical act is safe for the management of this pathology without delaying the others therapeutics and allowing a satisfactory quality of life.


Assuntos
Adenocarcinoma/cirurgia , Carcinoma Endometrioide/cirurgia , Carcinossarcoma/cirurgia , Colo/cirurgia , Neoplasias Ovarianas/cirurgia , Exenteração Pélvica , Reto/cirurgia , Adenocarcinoma/patologia , Adenocarcinoma de Células Claras/patologia , Adenocarcinoma de Células Claras/cirurgia , Adenocarcinoma Mucinoso/patologia , Adenocarcinoma Mucinoso/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anastomose Cirúrgica , Carcinoma Endometrioide/patologia , Carcinossarcoma/patologia , Colostomia , Cistadenocarcinoma Seroso/patologia , Cistadenocarcinoma Seroso/cirurgia , Cistectomia , Estudos de Viabilidade , Feminino , Humanos , Histerectomia , Ileostomia , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/patologia , Ovário/patologia , Cuidados Pré-Operatórios , Qualidade de Vida , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
7.
Toxicol In Vitro ; 20(6): 824-31, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16472967

RESUMO

Acetylcholinesterase inhibitors are commonly used as cognitive enhancers for dementia in aged people. Among them, tacrine (THA) but not galanthamine, was shown to exhibit hepatotoxicity which reduces its clinical use. PMS777, both a PAF antagonist and a new potent acetylcholinesterase inhibitor was recently demonstrated to reverse scopolamine-induced amnesia in mice without toxicity. In the present study, the effects of THA, galanthamine and PMS777 were compared in HepG2 cells on the oxidative parameters involved in the reported hepatotoxicity of THA. THA (> or = 10 microM) induced an oxidative stress as shown by elevated ROS and MDA production and by a decrease in GSH level. Moreover, mitochondrial membrane potential and redox status were decreased. At low concentrations (< or =10 microM), there was no significant disturbance. None of the oxidative stress markers was affected by PMS777 up to the maximum concentration tested and it is suggested that PMS777 is not cytotoxic for HepG2 cells. Galanthamine was also without cytotoxicity. Our results suggest that the toxic effect of THA above 10 microM may be caused by drug-induced mitochondrial energization impairment and destabilisation of membrane phospholipids associated with an oxidative stress. In contrast by preventing these dysfunctions, PMS777 could be safer than THA.


Assuntos
Inibidores da Colinesterase/toxicidade , Furanos/toxicidade , Galantamina/toxicidade , Fígado/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Tacrina/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Mitocôndrias/fisiologia , Fator de Ativação de Plaquetas/fisiologia
8.
Int J Gynecol Cancer ; 14(2): 229-33, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15086721

RESUMO

AIM: To assess the effect of laparoscopy on circulating tumor cell (CTC) detection in case of carcinosis. MATERIAL AND METHODS: We compared laparoscopy versus laparotomy on tumor cell blood release in an animal model of ovarian carcinosis obtained by intraperitoneal inoculation of IGR-OV1 cells in nude rats. Animals were randomly assigned to one of the following groups: CO(2) laparoscopy (L), gasless laparoscopy (GL), midline laparotomy (ML), or general anesthesia as control (C). A 0.5 ml blood sample was taken in each case before and after experiment and tested with a novel assay, ISET (isolation by size of epithelial tumor cells), which isolates CTC by filtration on account of their size. Statistics were performed with the Fisher's and the Chi-square tests. RESULTS: Ten rats were included in each group. We did not find any significant difference in CTC prevalence before and after surgery (2/14 versus 3/19, respectively, P = 1). Similarly, the three surgical accesses were equivalent with one post-experiment detection per group: 1/5 for L, 1/7 for ML, 1/7 for GL, and 1/6 for C (P = 0.9). CONCLUSION: This trial did not show any deleterious effect of laparoscopy on CTC when compared to laparotomy.


Assuntos
Laparoscopia/efeitos adversos , Laparotomia/efeitos adversos , Células Neoplásicas Circulantes/patologia , Neoplasias Ovarianas/cirurgia , Animais , Modelos Animais de Doenças , Feminino , Transplante de Neoplasias , Neoplasias Ovarianas/patologia , Distribuição Aleatória , Ratos , Ratos Nus
10.
Biochim Biophys Acta ; 1467(1): 7-17, 2000 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-10930504

RESUMO

In apical membrane vesicles from beef tracheal epithelia expressing up to 30% of the proteins as functional cystic fibrosis transmembrane conductance regulator (CFTR)-- i.e. a voltage-independent and PKA-sensitive 36Cl- flux--an ATPase activity, different from P, F0F1 and V types, was reproducibly detected. Its specific activity averaged 20 micromol Pi h(-1) mg(-1) with an apparent affinity for ATP of 530 +/- 30 microM. Its possible involvement in CFTR functions was supported by (1) the linear relationship between the ATPase activity and the magnitude of 36Cl- fluxes (turnover rate: 3 ATP hydrolyzed per CFTR per second), (2) the same rank of potency of ATP, ITP, GTP, UTP and CTP to be hydrolyzed and to open CFTR chloride channels, (3) the similar and parallel inhibition of the ATPase and CFTR Cl- fluxes by NS004 (IC50: 60 microM) and (4) the potency of anti-R domain antibodies to increase by 18% the ATPase activity.


Assuntos
Adenosina Trifosfatases/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/farmacologia , Traqueia/enzimologia , Adenosina Trifosfatases/antagonistas & inibidores , Trifosfato de Adenosina/metabolismo , Fosfatase Alcalina/metabolismo , Animais , Anticorpos/farmacologia , Benzimidazóis/farmacologia , Bovinos , Cloretos/metabolismo , Clorofenóis/farmacologia , Vesículas Revestidas/enzimologia , Regulador de Condutância Transmembrana em Fibrose Cística/análise , Regulador de Condutância Transmembrana em Fibrose Cística/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Células Epiteliais/enzimologia , Concentração de Íons de Hidrogênio , Hidrólise/efeitos dos fármacos , Cinética , Radioisótopos , Especificidade por Substrato
11.
J Biol Chem ; 275(3): 1976-86, 2000 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-10636900

RESUMO

Na,K-ATPase plays a crucial role in cellular ion homeostasis and is the pharmacological receptor for digitalis in man. Nine different human Na,K-ATPase isozymes, composed of 3 alpha and beta isoforms, were expressed in Xenopus oocytes and were analyzed for their transport and pharmacological properties. According to ouabain binding and K(+)-activated pump current measurements, all human isozymes are functional but differ in their turnover rates depending on the alpha isoform. On the other hand, variations in external K(+) activation are determined by a cooperative interaction mechanism between alpha and beta isoforms with alpha2-beta2 complexes having the lowest apparent K(+) affinity. alpha Isoforms influence the apparent internal Na(+) affinity in the order alpha1 > alpha2 > alpha3 and the voltage dependence in the order alpha2 > alpha1 > alpha3. All human Na,K-ATPase isozymes have a similar, high affinity for ouabain. However, alpha2-beta isozymes exhibit more rapid ouabain association as well as dissociation rate constants than alpha1-beta and alpha3-beta isozymes. Finally, isoform-specific differences exist in the K(+)/ouabain antagonism which may protect alpha1 but not alpha2 or alpha3 from digitalis inhibition at physiological K(+) levels. In conclusion, our study reveals several new functional characteristics of human Na,K-ATPase isozymes which help to better understand their role in ion homeostasis in different tissues and in digitalis action and toxicity.


Assuntos
Isoenzimas , ATPase Trocadora de Sódio-Potássio/metabolismo , ATPase Trocadora de Sódio-Potássio/farmacologia , Animais , Ligação Competitiva , Transporte Biológico , Membrana Celular/enzimologia , Clonagem Molecular , Relação Dose-Resposta a Droga , Eletrofisiologia , Ativação Enzimática/efeitos dos fármacos , Humanos , Cinética , Oócitos/metabolismo , Ouabaína/antagonistas & inibidores , Ouabaína/metabolismo , Potássio/farmacologia , RNA Complementar/metabolismo , Sódio/farmacologia , ATPase Trocadora de Sódio-Potássio/genética , Xenopus/metabolismo
12.
Cardiovasc Surg ; 7(1): 112-6, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10073770

RESUMO

The aim of this study was to determine if the intraoperative circumference of aortocoronary saphenous vein bypass grafts could be predicted from preoperative measurement with B-mode ultrasound sonography in 50 patients. The circumference of the saphenous vein was measured during stepwise increments of a thigh congestive cuff from 0 to 60 mmHg. The circumference of the corresponding segment of the coronary bypass vein graft was measured intraoperatively with callipers. The intraoperative circumference was higher (11.8+/-2.3 mm) than the preoperative circumference (10.2+/-2.4 mm, P=0.006) matched to its corresponding intraoperative mean arterial pressure (57+/-15 mmHg). The prediction of the intraoperative circumference by estimation from the preoperative pressure-circumference relationship fitted by a linear model (r = 0.412, P = 0.004) did not improve on the preoperative circumference matched by arterial pressure alone (r = 0.429, P = 0.003). The intraoperative circumference of the graft vein exceeded its preoperative circumference by 12%. Prediction of the intraoperative graft vein circumference is underestimated by a linear model of its preoperative compliance.


Assuntos
Ponte de Artéria Coronária , Veia Safena/anatomia & histologia , Veia Safena/transplante , Idoso , Elasticidade , Feminino , Humanos , Período Intraoperatório , Modelos Lineares , Masculino , Pessoa de Meia-Idade
13.
Clin Exp Hypertens ; 20(5-6): 669-74, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9682922

RESUMO

An unique endogenous digitalis-like factor (EDLF) has been previously purified from human newborn cord plasma and its differential effects tested on the three well defined functional isoforms (alpha1, alpha2 and alpha3) of the alpha subunits of Na+/K+-ATPase in rat. EDLF specifically inhibits the enzymatic activity. It differs from ouabain by three criteria: a preincubation with the membranes is required for full activity, no effect on the rat cerebral alpha3 isoform and a steep dose-response curve with the same apparent potency for rat alpha2 and alpha1 isoforms of high (10(-7) M) and low affinity (3 x 10(-5) M) for ouabain. These results indicate that the Na+/K+-ATPase inhibitor involved in the regulation of sodium and body fluid volume and present in neonate and adult human plasmas is distinct from ouabain.


Assuntos
Digoxina , Inibidores Enzimáticos/farmacologia , Isoenzimas/antagonistas & inibidores , Saponinas/farmacologia , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Animais , Encéfalo/enzimologia , Cardenolídeos , Membrana Celular/enzimologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/sangue , Inibidores Enzimáticos/isolamento & purificação , Humanos , Recém-Nascido , Isoenzimas/metabolismo , Rim/enzimologia , Miocárdio/enzimologia , Ouabaína/farmacologia , Volume Plasmático/efeitos dos fármacos , Volume Plasmático/fisiologia , Ratos , Ratos Wistar , Saponinas/sangue , Saponinas/isolamento & purificação , Sódio/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Espectrofotometria
14.
Cardiovasc Drugs Ther ; 12(6): 585-94, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10410828

RESUMO

LND-623 is a new aminosteroid analog of ouabain, with a greater separation between efficacy and toxicity than ouabain. To determine its mechanism of action, we studied its biochemical and physiological effects on human red blood cell sodium transports on different cellular structures regarded as sites of contractile control, and we compared its relative efficacy to ouabain in rat heart preparations and membrane-bound Na, K-ATPase isoenzymes. The response to ouabain was evaluated in Langendorff-perfused hearts and on purified membrane-bound Na, K-ATPase. LND-623 is 6.8-fold more efficient than ouabain in inhibiting the human Na+ pump (IC50 = 0.098 +/- 0.001 microM vs. 0.67 +/- 0.02 microM); (P < 0.0001). LND-623 had no effect on the following cellular functions: Na-Ca exchange, Na-K cotransport, Ca-ATPase, slow calcium channels, adenylate cyclase system, phosphodiesterase, and calcium sensitivity of the contractile protein system. The dose-response curve for the positive inotropic and inhibitory effects on rat cardiac isoenzymes produced by LND-623 were clearly biphasic. The amplitude of the maximum inotropic effect, without any toxic effect, was up to three-fold higher with LND-623 than with the same maximum dose of ouabain used. The strong positive inotropic effect of LND-623 in rats could be related to a specific inhibition of the two rat cardiac isoforms of the Na, K-ATPase.


Assuntos
Cardiotônicos/farmacologia , Isoenzimas/metabolismo , Manosídeos/farmacologia , Contração Miocárdica/efeitos dos fármacos , Pregnanos/farmacologia , ATPase Trocadora de Sódio-Potássio/metabolismo , Adenilil Ciclases/metabolismo , Animais , Cães , Eritrócitos/efeitos dos fármacos , Eritrócitos/enzimologia , Humanos , Técnicas In Vitro , Masculino , Membranas/efeitos dos fármacos , Membranas/enzimologia , Miofibrilas/enzimologia , Ouabaína/farmacologia , Diester Fosfórico Hidrolases/metabolismo , Ratos , Ratos Wistar , Trocador de Sódio e Cálcio/metabolismo , ATPase Trocadora de Sódio-Potássio/sangue , ATPase Trocadora de Sódio-Potássio/efeitos dos fármacos
17.
J Biol Chem ; 269(10): 7801-6, 1994 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-7510290

RESUMO

Inside-out apical membrane vesicles were isolated from bovine tracheal epithelium. They were enriched 13- and 18-fold in two apical membrane markers, alkaline phosphatase and gamma-glutamyltransferase, respectively, and presented a low level of contamination by basolateral and intracellular membranes. These apical membrane vesicles of homogeneous inside-out orientation were used to measure 36Cl- influx. The 36Cl- influx was found to be (i) voltage-insensitive (ii) diphenylcarboxylic acid-insensitive, and (iii) from 55 to 100% activated by cAMP-dependent protein kinase according to initial rates and accumulation capacities. This rapid and ATP-dependent activation was associated with phosphorylation of a 170-180-kDa protein but was not observed with a nonhydrolyzable nucleotide like adenosine 5'-O-(3-thiotriphosphate). Immunodetection experiments showed that the mature form of bovine cystic fibrosis transmembrane conductance regulator (CFTR) was only present in the apical membranes. As compared with the previously described characteristics of CFTR, the 36Cl- uptakes detected here are the in vitro manifestation of the functional form of bovine CFTR located at the apical level in these tracheal epithelial cells. Inside-out apical membrane vesicles, with freely accessible cytoplasmic sides and functional CFTR, offer a new model system to study CFTR.


Assuntos
Proteínas de Membrana/metabolismo , Traqueia/metabolismo , Animais , Transporte Biológico , Bovinos , Membrana Celular/metabolismo , Cloro/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística , Epitélio/metabolismo , Técnicas In Vitro , Fosforilação , Testes de Precipitina
18.
J Cardiovasc Pharmacol ; 22 Suppl 2: S96-8, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-7508043

RESUMO

Different isoforms of the (Na+ + K+)-ATPase are expressed in different cell types in which they contribute to specialized properties. Their biochemistry and physiology are complex. These isozymes vary in their sensitivity to cardiac glycosides and to intracellular Na+ and Ca2+ concentrations. Their functional expression at the membrane level in the different parts of kidney, heart, and brain varies with species and during ontogenesis. In rat heart, at birth and postpartum, there are quantitative and qualitative changes in the expression of the (Na+ + K+)-ATPase and Na+/Ca2+ exchange isoforms. The (Na+ + K+)-ATPase isozymes react differently to hormonal regulation and to physiopathological alterations, i.e., cardiac ischemia and cardiac hypertrophy. Considering the diversity of the (Na+ + K+)-ATPase isoforms and their numerous regulations, what could be the targets of endogenous (Na+ + K+)-ATPase inhibitors?


Assuntos
Cálcio/metabolismo , Proteínas de Transporte/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Sódio/metabolismo , Animais , Encéfalo/enzimologia , Cardiomegalia/enzimologia , Humanos , Isoenzimas/metabolismo , Rim/enzimologia , Infarto do Miocárdio/enzimologia , Miocárdio/enzimologia , Trocador de Sódio e Cálcio
19.
Arzneimittelforschung ; 42(11): 1301-5, 1992 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-1337248

RESUMO

20R 14 beta-amino 3 beta-rhamnosyl 5 beta-pregnan 20 beta-ol (LND 623, CAS 90520-42-6) was investigated and compared to digoxin in anesthetized dogs. The hemodynamic profiles showed: a) a pure positive inotropic action of LND-623; b) its potency was four-fold higher than that of digoxin and more marked in heart failure; c) its duration of action was maintained for at least 6 h. The onset and reversal of the inotropic effects of a single dose (3.3 nmol.kg-1.min-1) were faster with LND-623 than those of digoxin. This reversal is consistent with the faster dissociation profile observed at the level of the high affinity cardiac Na+,K(+)-ATPase receptor form. The advantage of LND-623 over digoxin resides in its larger therapeutic index (ratio of arrhythmogenic to inotropic responses) in anesthetized dogs with propranolol-induced heart failure. This index was 6 for LND-623 and 2 for digoxin.


Assuntos
Insuficiência Cardíaca/tratamento farmacológico , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Anestesia , Animais , Cardiotônicos/farmacologia , Digoxina/farmacologia , Cães , Feminino , Insuficiência Cardíaca/fisiopatologia , Hemodinâmica/efeitos dos fármacos , Masculino , Manosídeos/farmacologia , Contração Miocárdica/efeitos dos fármacos , Pregnanos/farmacologia , Propranolol/farmacologia
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