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1.
Health Policy ; 124(4): 339-344, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32115251

RESUMO

The national HIV/AIDS Programme has been a core health programme in Portugal, and has led the country's response to the HIV epidemics since the 1980s. In 2011, the Portuguese Government reorganised central services and reformed all vertical programmes, including the HIV/AIDS Programme. This paper describes the main features of that reform and analyses selected outcomes, as well as how those financial constraints affected the response to HIV/AIDS. Despite some transitory cuts in spending, the National Programme for HIV/AIDS Infection was able to successfully expand testing and prevention interventions. Strategic partnerships with non-governmental and community-based organisations were crucial to continue delivering adequate HIV testing services and reaching most-at-risk groups. Scaling-up access to pre-exposure prophylaxis (PrEP), improving access and adherence to antiretroviral therapy, and continuously promoting access to HIV testing services and HIV self-testing are the main challenges that the National Programme for HIV/AIDS Infection will face in the upcoming years.


Assuntos
Síndrome da Imunodeficiência Adquirida , Epidemias , Infecções por HIV , Profilaxia Pré-Exposição , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Síndrome da Imunodeficiência Adquirida/prevenção & controle , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle , Humanos , Portugal
2.
Anal Biochem ; 430(2): 141-50, 2012 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-22922799

RESUMO

Quantitation of individual monoclonal antibodies (mAbs) within a combined antibody drug product is required for preclinical and clinical drug development. We have developed two antitoxins, XOMA 3B and XOMA 3E, each consisting of three mAbs that neutralize type B and type E botulinum neurotoxin (BoNT/B and BoNT/E) to treat serotype B and E botulism. To develop mAb-specific binding assays for each antitoxin, we mapped the epitopes of the six mAbs. Each mAb bound an epitope on either the BoNT light chain (LC) or translocation domain (H(N)). Epitope mapping data were used to design LC-H(N) domains with orthogonal mutations to make them specific for only one mAb in either XOMA 3B or XOMA 3E. Mutant LC-H(N) domains were cloned, expressed, and purified from Escherichia coli. Each mAb bound only to its specific domain with affinity comparable to the binding to holotoxin. Further engineering of domains allowed construction of enzyme-linked immunosorbent assays (ELISAs) that could characterize the integrity, binding affinity, and identity of each of the six mAbs in XOMA 3B and 3E without interference from the three BoNT/A mAbs in XOMA 3AB. Such antigen engineering is a general method allowing quantitation and characterization of individual mAbs in a mAb cocktail that bind the same protein.


Assuntos
Anticorpos Monoclonais/imunologia , Ensaio de Imunoadsorção Enzimática , Reações Antígeno-Anticorpo , Toxinas Botulínicas/química , Toxinas Botulínicas/imunologia , Toxinas Botulínicas/metabolismo , Toxinas Botulínicas Tipo A , Mapeamento de Epitopos , Epitopos/imunologia , Engenharia de Proteínas , Estrutura Terciária de Proteína , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo
3.
Anal Biochem ; 421(2): 351-61, 2012 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-22037290

RESUMO

Quantitation of individual monoclonal antibodies (mAbs) within a combined antibody drug product is required for preclinical and clinical drug development, including pharmacokinetic (PK), toxicology, stability, and biochemical characterization studies of such drugs. We have developed an antitoxin, XOMA 3AB, consisting of three recombinant mAbs that potently neutralize the known subtypes of type A botulinum neurotoxin (BoNT/A). The three mAbs bind nonoverlapping BoNT/A epitopes with high affinity. XOMA 3AB is being developed as a treatment for botulism resulting from BoNT/A. To develop antibody-specific assays, we cloned, expressed, and purified BoNT/A domains from Escherichia coli. Each mAb bound only to its specific domain with affinity comparable to the binding to holotoxin. mAb-specific domains were used to develop an enzyme-linked immunosorbent assay (ELISA) for characterization of the integrity and binding activity of the three mAbs in the drug product. An electrochemiluminescence bridging assay that is robust to interference from components in serum was also developed, and we demonstrate that it can be used for PK assays. This type of antigen engineering to generate mAb-specific domains is a general method allowing quantitation and characterization of individual mAbs in a mAb cocktail that binds the same protein and is superior to anti-idiotype approaches.


Assuntos
Anticorpos Monoclonais/análise , Toxinas Botulínicas Tipo A/imunologia , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/análise , Anticorpos Neutralizantes/imunologia , Toxinas Botulínicas Tipo A/química , Toxinas Botulínicas Tipo A/genética , Toxinas Botulínicas Tipo A/isolamento & purificação , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Conformação Proteica
4.
Rev Port Cardiol ; 20 Suppl 5: V-37-42; discussion V-43-5, 2001 May.
Artigo em Português | MEDLINE | ID: mdl-11515299

RESUMO

The A.A. present a case of Ebstein's Disease, on a woman 48 years old. After stressing the clinical and laboratorial aspects, as well as hemodynamics and angiocardiography data, they summarize the operation, on which was used a human "dura-mater" valve in tricuspid position. There is no knowledge on literature of previous applications of this kind of valve on Ebstein's Disease. The patient, one year after the operation, is improving quiet well.


Assuntos
Bioprótese , Dura-Máter/transplante , Anomalia de Ebstein/cirurgia , Próteses Valvulares Cardíacas , Feminino , Humanos , Pessoa de Meia-Idade
5.
Control Clin Trials ; 22(1): 29-41, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11165421

RESUMO

The Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) is a randomized, practice-based trial sponsored by the National Heart, Lung, and Blood Institute (NHLBI). The double-blind, active-controlled component of ALLHAT was designed to determine whether the rate of the primary outcome-a composite of fatal coronary heart disease and nonfatal myocardial infarction-differs between diuretic (chlorthalidone) treatment and each of three other classes of antihypertensive drugs: a calcium antagonist (amlodipine), an angiotensin-converting enzyme inhibitor (lisinopril), and an alpha-adrenergic blocker (doxazosin) in high-risk hypertensive persons ages 55 years and older. In addition, 10,377 ALLHAT participants with mild to moderate hypercholesterolemia were also enrolled in a randomized, open-label trial designed to determine whether lowering serum LDL cholesterol with an HMG CoA reductase inhibitor (pravastatin) will reduce all-cause mortality as compared to a control group receiving "usual care." In January 2000, an independent data review committee recommended discontinuing the doxazosin treatment arm. The NHLBI director promptly accepted the recommendation. This article discusses the steps involved in the orderly closeout of one arm of ALLHAT and the dissemination of trial results. These steps included provisional preparations; the actual decision process; establishing a timetable; forming a transition committee; preparing materials and instructions; informing 65 trial officers and coordinators, 628 active clinics and satellite locations, 313 institutional review boards, over 42,000 patients, and the general public; reporting detailed trial results; and monitoring the closeout process. Control Clin Trials 2001;22:29-41


Assuntos
Sistemas de Notificação de Reações Adversas a Medicamentos , Anti-Hipertensivos/efeitos adversos , Doença das Coronárias/prevenção & controle , Doxazossina/efeitos adversos , Hipercolesterolemia/prevenção & controle , Hipertensão/tratamento farmacológico , Infarto do Miocárdio/prevenção & controle , Anti-Hipertensivos/uso terapêutico , Causas de Morte , Doença das Coronárias/mortalidade , Bases de Dados Factuais , Método Duplo-Cego , Doxazossina/uso terapêutico , Feminino , Insuficiência Cardíaca/induzido quimicamente , Insuficiência Cardíaca/mortalidade , Humanos , Hipercolesterolemia/mortalidade , Hipertensão/mortalidade , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/mortalidade , Pravastatina/efeitos adversos , Pravastatina/uso terapêutico , Medição de Risco , Taxa de Sobrevida , Resultado do Tratamento , Estados Unidos
6.
J Invest Dermatol ; 113(5): 788-95, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10571735

RESUMO

Nuclear receptors which interact with the retinoid X receptor are involved in the regulation of epidermal differentiation and development. We have recently shown that activators of the peroxisome proliferator-activated receptor and of the farnesoid X-activated receptor accelerate epidermal barrier maturation in fetal rat skin in vitro. In this study we asked whether cutaneous development in utero was affected by peroxisome proliferator-activated receptor or farnesoid X-activated receptor activators, or by an activator of another retinoid X receptor partner, liver X receptor. Activators of the peroxisome proliferator-activated receptor (clofibrate or linoleic acid), farnesoid X-activated receptor (farnesol or juvenile hormone III), or liver X receptor (22R-hydroxycholesterol), were injected into the amniotic fluid of fetal rats on gestational day 17. Fetal epidermal barrier function and morphology was assessed on day 19. Whereas vehicle-treated fetal rats displayed no measurable barrier (transepidermal water loss > 10 mg per cm2 per h), a measurable barrier was induced by the intra-amniotic administration of all activators tested (transepidermal water loss range 4.0-8.5 mg per cm2 per h). By light microscopy, control pups lacked a well-defined stratum corneum, whereas a distinct stratum corneum and a thickened stratum granulosum were present in treated pups. By electron microscopy, the extracellular spaces of the stratum corneum in control pups revealed a paucity of mature lamellar unit structures, whereas these structures filled the stratum corneum interstices in treated pups. Additionally, protein and mRNA levels of loricrin and filaggrin, two structural proteins of stratum corneum, were increased in treated epidermis, as were the activities of two lipid catabolic enzymes critical to stratum corneum function, beta-glucocerebrosidase and steroid sulfatase. Finally, peroxisome proliferator-activated receptor-alpha and -delta and liver X receptor-alpha and -beta mRNAs were detected in fetal epidermis by reverse transcriptase-polymerase chain reaction and northern analyses. The presence of these receptors and the ability of their activators to stimulate epidermal barrier and stratum corneum development suggest a physiologic role for peroxisome proliferator-activated receptor and liver X receptor and their endogenous ligands in the regulation of cutaneous development.


Assuntos
Proteínas de Ligação a DNA/farmacologia , Receptores Citoplasmáticos e Nucleares/fisiologia , Fenômenos Fisiológicos da Pele/efeitos dos fármacos , Pele/citologia , Pele/embriologia , Fatores de Transcrição/farmacologia , Fatores de Transcrição/fisiologia , Âmnio , Animais , Diferenciação Celular/efeitos dos fármacos , Clofibrato/farmacologia , Farneseno Álcool/farmacologia , Feminino , Feto/citologia , Hidroxicolesteróis/farmacologia , Injeções , Hormônios Juvenis/farmacologia , Proteínas Nucleares/farmacologia , Gravidez , Ratos , Ratos Sprague-Dawley , Sesquiterpenos/farmacologia , Ácido alfa-Linolênico/farmacologia
7.
Semin Cutan Med Surg ; 16(4): 249-56, 1997 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9421215

RESUMO

The prevalence of infections in the immunocompromised host is increasing. The oral cavity is a primary or sole site in many cases. It is important for the practicing clinician to recognize the more common infections in this growing patient population. Oral examinations are an essential component of all physical examinations, especially when immunosuppression is known or suspected. We recommend that all patients starting immunosuppressive therapy receive a comprehensive oral examination before the institution of such therapy to eliminate potential sources of oral and odontogenic infections. The examination should include full mouth dental radiographs and a complete soft-tissue examination. Timely, accurate diagnoses may have important implications with regard to management, prognosis, cost, morbidity, and mortality.


Assuntos
Hospedeiro Imunocomprometido , Doenças da Boca/microbiologia , Infecções Oportunistas/diagnóstico , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/terapia , Assistência Odontológica Integral , Custos e Análise de Custo , Humanos , Tolerância Imunológica , Imunossupressores/uso terapêutico , Doenças da Boca/diagnóstico , Doenças da Boca/diagnóstico por imagem , Doenças da Boca/terapia , Doenças da Boca/virologia , Micoses/diagnóstico , Micoses/terapia , Infecções Oportunistas/diagnóstico por imagem , Infecções Oportunistas/terapia , Infecções Oportunistas/virologia , Exame Físico , Prevalência , Prognóstico , Radiografia , Taxa de Sobrevida , Doenças Dentárias/diagnóstico , Doenças Dentárias/diagnóstico por imagem , Doenças Dentárias/microbiologia , Doenças Dentárias/terapia , Doenças Dentárias/virologia , Viroses/diagnóstico , Viroses/terapia
9.
J Neurotrauma ; 13(3): 149-62, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8965324

RESUMO

Laser-Doppler flowmetry (LDF) was used to record subcortical cerebral blood flow in hippocampus and striatum immediately following parasaggital fluid percussion brain injuries of mild to moderate severity (2.58 +/- 0.09 atm, 10-11 msec duration) in spontaneously breathing anesthetized rats. At 5 min postinjury, mean blood flow decreased bilaterally by 20-30% in both brain structures, and remained significantly reduced during the remainder of the 60 min postinjury recording interval. Blood flow did not change in the sham-injured rats. Subsequent beam-walk, beam-balance, and rope-hang assessments revealed significant neurological impairments in the injured rats but not in the sham controls. The magnitude of the blood flow changes and the severity of the ensuing neurological impairment were significantly correlated. Histopathological assessments revealed hemorrhagic contusions within ipsilateral cortical regions, occasional neuronal necrosis within underlying thalamus and CA3 and CA4 sectors of the hippocampus, and neuronal cell loss in the hilus of the dentate gyrus. In a second series of experiments, radiolabeled microspheres were used to validate the LDF blood flow measurements. The microsphere measurements revealed that the preinjury baseline and postinjury right hippocampal blood flow changes were not significantly altered by the intrahippocampal presence of an LDF probe, verifying that the LDF probe was not by itself an unacceptably disruptive influence on local cerebrovascular reactivity. Moreover, when right hippocampal blood flow was simultaneously evaluated in injured rats by both techniques, the relative blood flow changes were significantly correlated. These results indicate that laser-Doppler flowmetry provides a potentially useful means to appreciate acute regional cerebrovascular changes relative to other measures of outcome after brain trauma.


Assuntos
Lesões Encefálicas/fisiopatologia , Animais , Velocidade do Fluxo Sanguíneo , Pressão Sanguínea/fisiologia , Lesões Encefálicas/diagnóstico por imagem , Circulação Cerebrovascular/fisiologia , Fluxometria por Laser-Doppler , Masculino , Ratos , Ratos Sprague-Dawley , Fatores de Tempo , Ultrassonografia
12.
Am J Respir Cell Mol Biol ; 9(6): 578-85, 1993 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7504926

RESUMO

During development the fetal lung secretes fluid that is osmotically linked to chloride (Cl-) transport. One possible pathway for Cl- secretion across the fetal pulmonary epithelium is through the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is expressed in epithelia and functions as a Cl- channel regulated by cyclic adenosine monophosphate (cAMP)-dependent protein kinase and intracellular ATP. Previous studies have shown that CFTR mRNA is expressed throughout the human fetal pulmonary epithelium and CFTR protein can be immunoprecipitated from human fetal lung homogenates. In cultured fetal lung tissue explants, CFTR mRNA was localized to alveolar epithelial cells. To test the hypothesis that fetal alveolar epithelial cells express functional CFTR, we immunolocalized CFTR in human fetal lung and looked for evidence of Cl- secretion in cultured alveolar epithelial cell monolayers. Monoclonal anti-CFTR antibodies localized CFTR in cultured lung explants to the epithelial cells, predominantly at the apical surface. Bioelectric properties of cultured monolayers of midgestation fetal alveolar epithelial cells were measured in modified Ussing chambers. In unstimulated monolayers, transepithelial electrical potential difference (psi t) = -1.1 +/- 0.1 mV, transepithelial resistance (Rt) = 768 +/- 58 omega.cm2, and short-circuit current (Isc) = 1.9 +/- 0.2 microA/cm2 (mean +/- SE, n = 17). Addition of amiloride to the apical surface significantly decreased basal Isc. Apical diphenylamine-2-carboxylate (DPC), a Cl- channel inhibitor, caused no significant change in basal Isc. In the presence of apical amiloride, isoproterenol significantly increased Isc, a response that was inhibited by apical DPC and submucosal bumetanide. The cAMP agonists forskolin and IBMX also stimulated Isc.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Canais de Cloreto/metabolismo , AMP Cíclico/fisiologia , Proteínas de Membrana/metabolismo , Alvéolos Pulmonares/embriologia , Alvéolos Pulmonares/metabolismo , Anticorpos Monoclonais , Transporte Biológico/fisiologia , Células Cultivadas , Regulador de Condutância Transmembrana em Fibrose Cística , Células Epiteliais , Epitélio/embriologia , Epitélio/metabolismo , Feto/citologia , Feto/metabolismo , Humanos , Imuno-Histoquímica , Proteínas de Membrana/análise , Alvéolos Pulmonares/citologia
13.
J Immunol ; 151(5): 2707-16, 1993 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-7689613

RESUMO

Immunologic and enzyme digest epitope mapping techniques were used to compare and contrast the interactions of three mouse mAb, designated A10G10, A6, and B6, with human TNF-alpha. These antibodies have previously been shown to protect mouse and human cells from TNF toxicity. ELISA showed that the antibodies recognize predominantly conformational epitopes, and that native TNF binds at least two molecules of the same mAb. Enzyme digestion of native TNF bound to each of the mAb in turn showed that each of the antibodies binds to or sterically masks a large fraction of the exposed surface of TNF. These epitope mapping data were compared with four putative TNF cell receptor binding sites presented in the literature. The results are consistent with the hypothesis that these antibodies prevent TNF-induced cell death by binding to or sterically masking the TNF receptor binding site.


Assuntos
Anticorpos Monoclonais/imunologia , Epitopos/análise , Imunoglobulina G/imunologia , Fator de Necrose Tumoral alfa/imunologia , Sequência de Aminoácidos , Animais , Sítios de Ligação , Ligação Competitiva , Quimotripsina/farmacologia , Endopeptidases/farmacologia , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina G/classificação , Camundongos , Dados de Sequência Molecular , Elastase Pancreática/farmacologia , Receptores de Superfície Celular/metabolismo , Receptores do Fator de Necrose Tumoral , Fator de Necrose Tumoral alfa/metabolismo
14.
J Dev Physiol ; 19(1): 29-36, 1993 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8394851

RESUMO

Fluid secretion by the fetal pulmonary epithelium is thought to be important for normal lung development yet little is known about factors regulating its production. As prostaglandins are synthesized in human fetal lung and stimulate secretion in a variety of epithelia, we investigated the effect of prostaglandins E2 and F2a (PGE2 and PGF2 alpha) on ion transport and fluid secretion in cultured first trimester human fetal lung tissue explants. We used conventional microelectrodes to continuously record the transepithelial potential difference (psi t). The addition of either PGE2 or PGF2 alpha to the bathing solution significantly hyperpolarized the lumen negative psi t and the subsequent addition of bumetanide, an inhibitor of chloride secretion in other systems, depolarized psi t by approximately 60% suggesting chloride transport contributed to the voltage. To assess whether this acute change in psi t represented stimulation of fluid secretion, we measured the change in luminal area of the explants after a 24-h exposure to prostaglandins. Both PGE2 and PGF2 alpha caused significant increases in the mean % luminal area of the explants compared with control tissues consistent with a stimulation of lung fluid secretion. Cultured lung tissue explants produced prostaglandins E2 and F2 alpha as assessed by radioimmunoassay of cell culture media samples and both prostaglandins stimulated cAMP accumulation in the explants. These findings show that lung fluid secretion in the human fetal pulmonary epithelium can be stimulated by prostaglandins. This effect may be mediated through cAMP dependent pathways. Prostaglandins may play a physiologic role in regulation of fetal lung fluid transport in vivo.


Assuntos
Dinoprosta/farmacologia , Dinoprostona/farmacologia , Feto/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Líquidos Corporais/efeitos dos fármacos , Líquidos Corporais/metabolismo , Calcimicina/farmacologia , Cloretos/metabolismo , Técnicas de Cultura , AMP Cíclico/biossíntese , Dinoprosta/biossíntese , Dinoprostona/biossíntese , Epitélio/efeitos dos fármacos , Epitélio/metabolismo , Feto/fisiologia , Humanos , Indometacina/farmacologia , Pulmão/metabolismo , Potenciais da Membrana/efeitos dos fármacos
15.
Am J Respir Cell Mol Biol ; 6(6): 609-16, 1992 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1317192

RESUMO

We studied lung explants in submersion organ culture to examine the role of the developing fetal alveolar epithelium in the production of lung fluid. Fourteen-day-gestation fetal rat lungs were grown in a collagen gel matrix supplemented with F-12 media and 10% fetal calf serum. In this model, the lung continues to grow, secrete fluid, and become progressively cystic in morphology. There is gradual thinning of the distal epithelial layer, which is lined by alveolar type II cells and their precursors. After 6 to 8 days in culture, we impaled the cyst walls with a microelectrode and continuously recorded the transepithelial potential (psi t). Stable, baseline transepithelial potentials of -1.1 to -6.2 mV (mean +/- SEM = -3.3 +/- 0.11 mV, lumen negative, n = 34) were measured in bicarbonate-buffered Ringer's solution, suggesting active electrolyte transport. When bumetanide, an inhibitor of chloride secretion in other systems, was added to the bathing solution, psi t decreased from a baseline of -3.5 +/- 0.07 mV (mean +/- SEM) to a value of -2.2 +/- 0.07 mV, suggesting chloride transport contributes to the voltage (n = 18, P less than 0.0005). Isoproterenol hyperpolarized psi t from a baseline of -4.3 +/- 1.0 mV to -6.5 +/- 1.0 mV (n = 7, P less than 0.005). 8-(4-Chlorophenylthio) adenosine 3':5'cyclic monophosphate (CPT-cAMP) plus isobutylmethylxanthine (IBMX) similarly hyperpolarized psi t from a baseline of -4.6 +/- 0.4 mV to -7.3 +/- 0.7 mV (n = 11, P less than 0.005). Addition of bumetanide after stimulation with isoproterenol or CPT-cAMP/IBMX depolarized psi t.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Líquidos Corporais/metabolismo , Alvéolos Pulmonares/metabolismo , Animais , Cloretos/metabolismo , Epitélio/metabolismo , Epitélio/fisiologia , Feto , Isoproterenol/farmacologia , Potenciais da Membrana , Microscopia Eletrônica , Técnicas de Cultura de Órgãos , Alvéolos Pulmonares/embriologia , Ratos , ATPase Trocadora de Sódio-Potássio/fisiologia
16.
Am J Physiol ; 262(4 Pt 1): L472-81, 1992 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1373570

RESUMO

We studied the developmental expression of the cystic fibrosis (CF) gene in human lung tissue from normal and CF-affected fetuses. Two unrelated CF fetuses, both homozygous for the delta F508 deletion, were examined. Cystic fibrosis transmembrane conductance regulator (CFTR) mRNA was present in second-trimester CF lung and in first- and second-trimester normal lung as assessed by amplification of reverse transcribed total RNA with the use of the polymerase chain reaction. CFTR protein was identified by immunoprecipitation in normal second-trimester fetal lung explants. To evaluate possible functional consequences of CF in the fetus, lung tissue explants were grown in submersion organ culture. By light and electron microscopy, the CF fetal lung explants appeared normal. When explants from normal fetal lung were exposed to 8-(4-chlorophenylthio) adenosine 3',-5'cyclic monophosphate (CPT-cAMP), and 3-isobutyl-1-methylxanthine (IBMX) for 24 h, the intraluminal fluid content increased, as assessed by a 40 +/- 4% increase in cross-sectional diameter. In contrast, identically treated CF explants showed no significant change in explant diameter (3 +/- 1.6%). The transepithelial potential (psi t) across fetal lung explants was measured with microelectrodes. In normal second-trimester explants, CPT-cAMP and IBMX caused hyperpolarization of psi t (-0.93 +/- 14 mV to -4.3 +/- 1.2 mV); in contrast, CF fetal lung explants showed no significant change in psi t with CPT-cAMP and IBMX (-0.84 +/- 0.07 mV to -1.21 +/- 0.26 mV). This study confirms the presence of CFTR mRNA and protein in human fetal lung and suggests that although the CF fetal lung appears normal morphologically, there is a defect in cAMP-mediated fluid secretion in the lung of the CF fetus.


Assuntos
Líquidos Corporais/metabolismo , AMP Cíclico/fisiologia , Feto/metabolismo , Pulmão/ultraestrutura , Proteínas de Membrana/metabolismo , Sequência de Bases , Fibrose Cística/embriologia , Fibrose Cística/metabolismo , Fibrose Cística/patologia , Regulador de Condutância Transmembrana em Fibrose Cística , Eletrofisiologia , Feminino , Feto/fisiologia , Humanos , Proteínas de Membrana/genética , Microscopia Eletrônica , Sondas Moleculares/genética , Dados de Sequência Molecular , Gravidez , Segundo Trimestre da Gravidez , RNA Mensageiro/metabolismo
18.
Am J Physiol ; 262(3 Pt 1): L270-9, 1992 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1372486

RESUMO

We studied human fetal lung tissue in submersion organ culture to determine whether the bronchopulmonary epithelium secretes fluid during development. In this system the acinar tubules continued to grow, secrete fluid, and become progressively dilated. Baseline transepithelial potential differences (psi t) of -0.5 to -11 mV (mean, -3.8 mV, lumen negative, n = 27) were measured with microelectrodes after 3-8 days in culture, suggesting active electrolyte transport. Bumetanide (500 microM), an inhibitor of chloride secretion in other systems, decreased the basal psi t from -5 +/- 1.5 to -3.2 +/- 1.6 (SE) mV (P less than 0.05, n = 6), suggesting that chloride transport contributed to the voltage. Isoproterenol (5 microM) increased the baseline psi t from -5.6 +/- 2.1 to -9.2 +/- 2.5 (SE) mV (P less than 0.05, n = 4). Subsequent addition of bumetanide inhibited the isoproterenol-induced stimulation of the psi t by 20% (P less than 0.05). 8-(4-chlorophenylthio)adenosine 3',5'-cyclic monophosphate. (CPT-cAMP, 50 microM) and 3-isobutyl 1-methylxanthine (IBMX, 100 microM) had similar effects, causing an increase in the psi t from -2.2 +/- 0.5 to -8 +/- 1.6 (SE) mV, an effect that was inhibited by the addition of bumetanide (P less than 0.005, n = 6). Both isoproterenol and CPT-cAMP/IBMX produced significant increases in the percentage luminal area of the explants at 12 and 24 h after exposure compared with control. We conclude that 1) the developing bronchopulmonary epithelium (acinar tubules) contributes to lung fluid production in the human fetus, 2) fetal lung fluid secretion is chloride dependent, and 3) chloride secretion and fluid secretion may be stimulated by a beta-agonist and cAMP.


Assuntos
Pulmão/embriologia , 1-Metil-3-Isobutilxantina/farmacologia , Líquidos Corporais/metabolismo , Bumetanida/farmacologia , AMP Cíclico/farmacologia , Epitélio/efeitos dos fármacos , Epitélio/metabolismo , Epitélio/ultraestrutura , Humanos , Iodoacetamida/farmacologia , Isoproterenol/farmacologia , Cinética , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/ultraestrutura , Potenciais da Membrana , Microscopia Eletrônica , Técnicas de Cultura de Órgãos , Ouabaína/farmacologia
20.
J Biol Chem ; 263(36): 19618-25, 1988 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-2848835

RESUMO

The steady state rate of ATP hydrolysis (v) by the gastric H,K-ATPase and the steady state level of phosphoenzyme (E-P) have been measured at 0 and 10 mM KCl; both v and E-P have a nonhyperbolic dependence on the ATP concentration that is consistent with negative cooperativity. The ratio of the rate of hydrolysis to phosphoenzyme (v/[E-P]) was found to vary with the concentration of ATP. Thus, for the rate law v = [E-P].k, k must be a function of the ATP concentration. This requires that ATP be able to bind to E-P or to an enzyme form that occurs after E-P but prior to an irreversible step, such as the loss of inorganic phosphate (Pi). At low ATP concentrations, product inhibition by Pi gives concave downward plots of 1/v against Pi concentration. Pi increases the apparent Km and decreases the apparent Vm. At saturating ATP concentrations, Pi is a noncompetitive inhibitor. These data show that ATP and Pi can bind to the H,K-ATPase simultaneously. They are inconsistent with mechanisms where the binding of ATP and Pi is mutually exclusive.


Assuntos
Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Microssomos/enzimologia , Fosfatos/metabolismo , Estômago/enzimologia , Animais , ATPase Trocadora de Hidrogênio-Potássio , Cinética , Matemática , Modelos Teóricos , Fosfoproteínas/metabolismo , Ligação Proteica , Suínos
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