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1.
Am J Physiol Gastrointest Liver Physiol ; 304(5): G516-26, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-23275617

RESUMO

Pancreatic acinar cells express proteinase-activated receptor-2 (PAR2) that is activated by trypsin-like serine proteases and has been shown to exert model-specific effects on the severity of experimental pancreatitis, i.e., PAR2(-/-) mice are protected from experimental acute biliary pancreatitis but develop more severe secretagogue-induced pancreatitis. P2pal-18S is a novel pepducin lipopeptide that targets and inhibits PAR2. In studies monitoring PAR2-stimulated intracellular Ca(2+) concentration changes, we show that P2pal-18S is a full PAR2 inhibitor in acinar cells. Our in vivo studies show that P2pal-18S significantly reduces the severity of experimental biliary pancreatitis induced by retrograde intraductal bile acid infusion, which mimics injury induced by endoscopic retrograde cholangiopancreatography (ERCP). This reduction in pancreatitis severity is observed when the pepducin is given before or 2 h after bile acid infusion but not when it is given 5 h after bile acid infusion. Conversely, P2pal-18S increases the severity of secretagogue-induced pancreatitis. In vitro studies indicate that P2pal-18S protects acinar cells against bile acid-induced injury/death, but it does not alter bile acid-induced intracellular zymogen activation. These studies are the first to report the effects of an effective PAR2 pharmacological inhibitor on pancreatic acinar cells and on the severity of experimental pancreatitis. They raise the possibility that a pepducin such as P2pal-18S might prove useful in the clinical management of patients at risk for developing severe biliary pancreatitis such as occurs following ERCP.


Assuntos
Doenças Biliares/prevenção & controle , Lipopeptídeos/farmacologia , Pancreatite/prevenção & controle , Receptor PAR-2/antagonistas & inibidores , Células Acinares/efeitos dos fármacos , Animais , Ácidos e Sais Biliares/metabolismo , Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Ceruletídeo/farmacologia , Colangiopancreatografia Retrógrada Endoscópica , Quimotripsinogênio/metabolismo , Corantes , Ativação Enzimática/efeitos dos fármacos , Precursores Enzimáticos/metabolismo , Cálculos Biliares/prevenção & controle , Indicadores e Reagentes , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Propídio , Tripsinogênio/metabolismo
2.
BJS Open ; 3(5): 722-732, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31592517

RESUMO

Background: Emergency and essential surgical, obstetric and anaesthesia (SOA) care are now recognized components of universal health coverage, necessary for a functional health system. To improve surgical care at a national level, strategic planning addressing the six domains of a surgical system is needed. This paper details a process for development of a national surgical, obstetric and anaesthesia plan (NSOAP) based on the experiences of frontline providers, Ministry of Health officials, WHO leaders, and consultants. Methods: Development of a NSOAP involves eight key steps: Ministry support and ownership; situation analysis and baseline assessments; stakeholder engagement and priority setting; drafting and validation; monitoring and evaluation; costing; governance; and implementation. Drafting a NSOAP involves defining the current gaps in care, synthesizing and prioritizing solutions, and providing an implementation and monitoring plan with a projected cost for the six domains of a surgical system: infrastructure, service delivery, workforce, information management, finance and governance. Results: To date, four countries have completed NSOAPs and 23 more have committed to development. Lessons learned from these previous NSOAP processes are described in detail. Conclusion: There is global movement to address the burden of surgical disease, improving quality and access to SOA care. The development of a strategic plan to address gaps across the SOA system systematically is a critical first step to ensuring countrywide scale-up of surgical system-strengthening activities.


Antecedentes: En la actualidad, se reconoce que la atención quirúrgica, obstétrica y anestésica urgente y esencial (surgical, obstetric, and anaesthesia, SOA) es uno de los componentes de la cobertura sanitaria universal y un elemento necesario para el funcionamiento de un sistema de salud. Para mejorar la atención quirúrgica a nivel nacional, se necesita una planificación estratégica que aborde los seis dominios de un sistema quirúrgico. En este artículo, se detalla el proceso para el desarrollo de un plan nacional de cirugía, obstetricia y anestesia (national surgical, obstetric, and anaesthesia plan, NSOAP) basado en las experiencias de los principales proveedores, los funcionarios del Ministerio de Salud, los líderes de la Organización Mundial de la Salud y consultores. Métodos: El desarrollo de un NSOAP incluye ocho pasos clave: (1) apoyo y dependencia del ministerio, (2) análisis de la situación y evaluaciones de referencia, (3) compromiso de los agentes implicados y establecimiento de prioridades, (4) redacción y validación, (5) seguimiento y evaluación, (6) análisis de costes, (7) gobernanza y (8) implementación. Redactar un NSOAP implica definir los déficits actuales en la atención, sintetizar y priorizar soluciones, y proporcionar un plan de implementación y seguimiento con unos costes proyectados para los seis dominios de un sistema quirúrgico: infraestructura, prestación de servicios, personal, gestión de la información, finanzas y gobernanza. Resultados: Hasta la fecha, cuatro países han completado un NSOAP y 23 más se han comprometido con su desarrollo. Las lecciones aprendidas de estos procesos previos de NSOAP se describen con detalle. Conclusiones: Existe un movimiento global para abordar la carga de las enfermedades que precisan cirugía, mejorar la calidad y el acceso a la atención SOA. El desarrollo de un plan estratégico para la aproximación sistemáticamente los déficits en todo el sistema SOA es un primer paso crítico para garantizar la ampliación a nivel nacional de las actividades de fortalecimiento del sistema quirúrgico.


Assuntos
Anestesia/métodos , Serviços Médicos de Emergência/normas , Obstetrícia/organização & administração , Procedimentos Cirúrgicos Operatórios/métodos , Anestesia/economia , Anestesia/normas , Atenção à Saúde/economia , Atenção à Saúde/organização & administração , Feminino , Implementação de Plano de Saúde/métodos , Mão de Obra em Saúde/organização & administração , Humanos , Gestão da Informação , Liderança , Programas Nacionais de Saúde/organização & administração , Obstetrícia/economia , Obstetrícia/normas , Participação dos Interessados , Procedimentos Cirúrgicos Operatórios/economia , Procedimentos Cirúrgicos Operatórios/normas , Assistência de Saúde Universal , Organização Mundial da Saúde/economia , Organização Mundial da Saúde/organização & administração
3.
J Clin Invest ; 77(5): 1668-74, 1986 May.
Artigo em Inglês | MEDLINE | ID: mdl-2422212

RESUMO

Young female mice fed a choline-deficient, ethionine-supplemented (CDE) diet rapidly develop acute hemorrhagic pancreatitis. We have observed that pancreatic acini prepared from these mice are unable to secrete amylase in response to addition of the cholinergic agonist carbachol, although they retain the ability to secrete amylase in response to the Ca2+ ionophore A23187. The CDE diet does not alter the binding characteristics (Kd or the maximal number of binding sites) for muscarinic cholinergic receptors as tested using the antagonist [3H]N-methylscopolamine nor the competition for this binding by carbachol. Addition of carbachol to acini prepared from mice fed the CDE diet does not result in as marked an increase in cytosolic free Ca2+ levels as that noted in control samples (evaluated using quin2 fluorescence). These observations indicate that the CDE diet interferes with stimulus-secretion coupling in mouse pancreatic acini at a step subsequent to hormone-receptor binding and prior to Ca2+ release. This conclusion is confirmed by our finding that the hormone-stimulated generation of [3H]inositol phosphates (inositol trisphosphate, inositol bisphosphate, and inositol monophosphate) from acini labeled with [3H]myoinositol is markedly reduced in acini prepared from mice fed the CDE diet. This reduction is not due to a decrease in phosphatidylinositol-4,5-bisphosphate. This communication represents the first report of a system in which a blockade of inositol phosphate generation can be related to a physiologic defect and pathologic lesion.


Assuntos
Deficiência de Colina/metabolismo , Etionina/farmacologia , Fosfatos de Inositol/biossíntese , Pâncreas/metabolismo , Pancreatite/metabolismo , Fosfatos Açúcares/biossíntese , Aminoquinolinas , Amilases/metabolismo , Animais , Calcimicina/farmacologia , Cálcio/análise , Carbacol/farmacologia , Diglicerídeos/farmacologia , Ativação Enzimática/efeitos dos fármacos , Feminino , Fluorescência , Inositol 1,4,5-Trifosfato , Camundongos , N-Metilescopolamina , Pancreatite/etiologia , Proteína Quinase C/análise , Derivados da Escopolamina/metabolismo , Trítio , Fosfolipases Tipo C/análise
4.
J Clin Invest ; 87(4): 1280-5, 1991 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-2010541

RESUMO

The complex events by which digestive enzyme zymogens and lysosomal hydrolases are segregated from each other and differentially transported to their respective membrane-bound intracellular organelles in the pancreas have been noted to be disturbed during the early stages of several models of experimental pancreatitis. As a result, lysosomal hydrolases such as cathepsin B are redistributed to the subcellular zymogen granule-rich fraction and lysosomal hydrolases as well as digestive enzyme zymogens are colocalized within large cytoplasmic vacuoles. The current study was designed to create an in vitro system that would reproduce this redistribution phenomenon. Our results indicate that cathepsin B redistribution occurs when rat pancreatic fragments are incubated with a supramaximally stimulating concentration of the cholecystokinin analogue caerulein along with plasma from an animal subjected to in vivo supramaximal caerulein stimulation. Neither the plasma nor a supramaximally stimulating concentration of caerulein, alone, is sufficient to induce in vitro cathepsin B redistribution. The ability of the plasma to induce in vitro cathepsin redistribution is dependent upon its content of a 10,000-30,000-D protein and is lost by exposure to protease inhibitors. In vitro cathepsin B redistribution also occurs when rat pancreatic fragments are incubated with plasma obtained from opossums with hemorrhagic necrotizing pancreatitis caused by bile/pancreatic duct ligation.


Assuntos
Catepsina B/metabolismo , Ceruletídeo/farmacologia , Endopeptidases/sangue , Lisossomos/enzimologia , Pâncreas/enzimologia , Pancreatite/enzimologia , Animais , Compartimento Celular , Grânulos Citoplasmáticos/metabolismo , Endopeptidases/química , Técnicas In Vitro , Peso Molecular , Gambás , Pancreatite/sangue , Ratos
5.
J Clin Invest ; 95(5): 2222-31, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7537759

RESUMO

Cell necrosis in acute experimental pancreatitis is preceded by a redistribution of digestive enzymes into a lysosomal subcellular compartment. We have investigated whether endocytosis from the acinar cell lumen might contribute to this disturbance of intracellular compartmentation. In an animal model of pancreatitis involving pancreatic bile duct ligation in opossums, we have studied in vivo endocytosis of dextran 40 and [14C]dextran 70, cationized ferritin, and horseradish peroxidase from the apical surface of acinar cells before the onset of necrosis. Marker solutions were instilled into the pancreatic duct of anesthetized animals at physiological pressure. Tissue samples obtained at intervals of up to 60 min after instillation of markers were studied by electron microscopy and electron microscope autoradiography. All markers were taken up by acinar cells in control animals and in animals with obstructed pancreatic bile ducts. Markers for membrane-mediated endocytosis (cationated ferritin and horseradish peroxidase) were transported to lysosomes in both groups. In contrast, the fluid-phase tracer dextran was transported to the secretory pathway in controls but to lysosomes after duct ligation. Since dextran and luminally present secretory proteins can be expected to follow the same route after endocytosis, our findings suggest that altered intracellular targeting of endocytosed proteases might be one mechanism by which digestive zymogens reach an intracellular compartment in which premature activation can occur. This phenomenon may be a critical and early event in the pathogenesis of biliary pancreatitis.


Assuntos
Ductos Biliares/fisiologia , Endocitose , Pâncreas/metabolismo , Pancreatite/patologia , Pancreatite/fisiopatologia , Doença Aguda , Animais , Gatos , Grânulos Citoplasmáticos/metabolismo , Grânulos Citoplasmáticos/patologia , Grânulos Citoplasmáticos/ultraestrutura , Dextranos/metabolismo , Modelos Animais de Doenças , Feminino , Ferritinas/metabolismo , Peroxidase do Rábano Silvestre , Cinética , Lisossomos/metabolismo , Lisossomos/patologia , Lisossomos/ultraestrutura , Masculino , Microscopia Eletrônica , Necrose , Gambás , Pâncreas/patologia , Pâncreas/ultraestrutura , Fatores de Tempo
6.
J Clin Invest ; 87(3): 865-9, 1991 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1705567

RESUMO

Lysosomal hydrolases such as cathepsin B are apically secreted from rabbit pancreatic acinar cells via a regulated as opposed to a constitutive pathway. Intravenous infusion of the cholecystokinin analogue caerulein results in highly correlated apical secretion of digestive and lysosomal enzymes, suggesting that they are discharged from the same presecretory compartment (zymogen granules). Lysosomal enzymes appear to enter that compartment as a result of missorting. After 7 h of duct obstruction is relieved, caerulein-stimulated apical secretion of cathepsin B and amylase is increased, but the ratio of cathepsin B to amylase secretion is not different than that following caerulein stimulation of animals never obstructed. These findings indicate that duct obstruction causes an increased amount of both lysosomal and digestive enzymes to accumulate within the secretagogue releasable compartment but that duct obstruction does not increase the degree of lysosomal enzyme missorting into that compartment. Pancreatic duct obstruction causes lysosomal hydrolases to become colocalized with digestive enzymes in organelles that, in size and distribution, resemble zymogen granules but that are not subject to secretion in response to secretagogue stimulation. These organelles may be of importance in the development of pancreatitis.


Assuntos
Catepsina B/metabolismo , Lisossomos/enzimologia , Pâncreas/metabolismo , Pancreatopatias/enzimologia , Amilases/metabolismo , Animais , Ceruletídeo/farmacologia , Relação Dose-Resposta a Droga , Feminino , Masculino , Pâncreas/citologia , Ductos Pancreáticos , Coelhos , Taxa Secretória/efeitos dos fármacos
7.
J Clin Invest ; 99(3): 506-12, 1997 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-9022085

RESUMO

The mechanisms by which short-term ethanol administration alters pancreatic exocrine function are unknown. We have evaluated the effects of ethanol administration on pancreatic secretion of digestive enzymes. In our studies, anesthetized as well as conscious rats were given ethanol at a rate sufficient to cause the blood ethanol concentration to reach levels associated with clinical intoxication. Ethanol was administered over a 2-h period during which blood ethanol levels remained stably elevated. We report that intravenous administration of ethanol results in a transient increase in pancreatic amylase output and plasma cholecystokinin (CCK) levels. The ethanol-induced increase in amylase output can be completely inhibited by the CCK-A receptor antagonist L-364,718 and partially inhibited by the muscarinic cholinergic antagonist atropine. The ethanol-induced rise in amylase output can be completely prevented by instillation of trypsin into the duodenum or by lavage of the duodenum with saline during ethanol administration. Furthermore, the intraduodenal activity of a CCK-releasing factor is increased by infusion of ethanol. These studies indicate that administration of ethanol causes rat pancreatic exocrine secretion to increase. This phenomenon is mediated by a trypsin-sensitive CCK-releasing factor which is present within the duodenal lumen. These observations lead us to speculate that repeated CCK-mediated ethanol-induced stimulation of pancreatic digestive enzyme secretion may play a role in the events which link ethanol abuse to the development of pancreatic injury.


Assuntos
Alcoolismo/metabolismo , Sistema Digestório/enzimologia , Enzimas/metabolismo , Etanol/toxicidade , Substâncias de Crescimento/fisiologia , Peptídeos e Proteínas de Sinalização Intercelular , Pancreatite/induzido quimicamente , Pancreatite/metabolismo , Amilases/metabolismo , Animais , Atropina/farmacologia , Benzodiazepinonas/farmacologia , Colecistocinina/sangue , Colecistocinina/metabolismo , Devazepida , Duodeno/efeitos dos fármacos , Duodeno/metabolismo , Etanol/sangue , Substâncias de Crescimento/metabolismo , Antagonistas de Hormônios/farmacologia , Masculino , Antagonistas Muscarínicos/farmacologia , Ratos , Ratos Wistar , Tripsina/farmacologia , Inibidor da Tripsina Pancreática de Kazal
8.
J Clin Invest ; 106(1): 81-9, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10880051

RESUMO

Rodents given a supramaximally stimulating dose of cholecystokinin or its analogue cerulein develop acute pancreatitis with acinar cell injury, pancreatic inflammation, and intrapancreatic digestive enzyme (i.e., trypsinogen) activation. Prior thermal stress is associated with heat shock protein 70 (HSP70) expression and protection against cerulein-induced pancreatitis. However, thermal stress can also induce expression of other HSPs. The current studies were performed using an in vitro system to determine whether HSP70 can actually mediate protection against pancreatitis and, if so, to define the mechanism underlying that protection. We show that in vitro exposure of freshly prepared rat pancreas fragments to a supramaximally stimulating dose of cerulein results in changes similar to those noted in cerulein-induced pancreatitis, i.e., intra-acinar cell trypsinogen activation and acinar cell injury. Short-term culture of the fragments results in HSP70 expression and loss of the pancreatitis-like changes noted after addition of cerulein. The culture-induced enhanced HSP70 expression can be prevented by addition of either the flavonoid antioxidant quercetin or an antisense oligonucleotide to HSP70. Under these latter conditions, addition of a supramaximally stimulating concentration of cerulein results in trypsinogen activation and acinar cell injury. These findings indicate that the protection against cerulein-induced pancreatitis that follows culture-induced (and possibly thermal) stress is mediated by HSP70. They suggest that the HSP acts by preventing trypsinogen activation within acinar cells.


Assuntos
Proteínas de Choque Térmico HSP70/fisiologia , Pâncreas/patologia , Tripsinogênio/metabolismo , Animais , Ceruletídeo/farmacologia , Ativação Enzimática , Proteínas de Choque Térmico HSP70/análise , Oligonucleotídeos Antissenso/farmacologia , Oligopeptídeos/análise , Técnicas de Cultura de Órgãos , Quercetina/farmacologia , Ratos , Ratos Wistar
9.
J Clin Invest ; 106(3): 439-48, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10930447

RESUMO

Induction of NF-kappaB-dependent gene expression plays an important role in a number of biological processes including inflammation and ischemia-reperfusion injury. However, few attempts aimed at selective regulation of this transcription factor have been successful. We report here that a naturally occurring antibacterial peptide PR39 reversibly binds to the alpha 7 subunit of the 26S proteasome and blocks degradation of NF-kappa B inhibitor I kappa B alpha by the ubiquitin-proteasome pathway without affecting overall proteasome activity. I kappa B alpha phosphorylation and ubiquitination occur normally after PR39 treatment, and binding of valosin-containing proteins is not impaired. The inhibition of I kappa B alpha degradation abolishes induction of NF-kappa B-dependent gene expression in cell culture and in mouse models of acute pancreatitis and myocardial infarction, including upregulation of endothelial adhesion proteins VCAM-1 and ICAM-1. In the latter model, sustained infusion of PR39 peptide resulted in significant reduction of myocardial infarct size. PR39 and related peptides may provide novel means to regulate cellular function and to control of NF-kappa B-dependent gene expression for therapeutic purposes.


Assuntos
Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos , Cisteína Endopeptidases/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas I-kappa B , Complexos Multienzimáticos/metabolismo , Peptídeos/farmacologia , Ubiquitinas/antagonistas & inibidores , Animais , Anti-Infecciosos/metabolismo , Células Cultivadas , Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos ICR , Camundongos Transgênicos , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/genética , Infarto do Miocárdio/metabolismo , Inibidor de NF-kappaB alfa , NF-kappa B/antagonistas & inibidores , NF-kappa B/metabolismo , Pancreatite/tratamento farmacológico , Pancreatite/genética , Pancreatite/metabolismo , Peptídeos/genética , Peptídeos/metabolismo , Complexo de Endopeptidases do Proteassoma , Suínos , Ubiquitinas/metabolismo
10.
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
11.
Biochim Biophys Acta ; 686(2): 240-4, 1982 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-6282327

RESUMO

The radioiodinated pindolol analogs 125I-labeled cyanopindolol ([125I]CYP) and 125I-labeled hydroxybenzylpindolol ([125I]HBP) have been used to study binding to human platelet beta-adrenergic receptors. [125I]CYP binds to a saturable class of binding sites on platelet membranes with a dissociation constant (Kd) of 14 +/- 3 pM and maximal binding capacity (Bmax) of 18 +/- 4 fmol/mg protein. Binding of [125I]CYP is reversible and is characterized by forward and reverse rate constants of 1.8 . 10(7) s-1 . M-1 and 3.8 . 10(-4) s-1, respectively. [125I]HBP binds to a saturable class of platelet membrane sites with a Kd of 50 +/- 10 pM and Bmax of 32 +/- 6 fmol/mg protein. [125I]HBP also binds to a saturable class of sites on intact platelets with a Kd of 58 +/- 14 pM and Bmax of 24 +/- 4 molecules per platelet. Binding of [125I]CYP and [125I]HBP is stereospecifically inhibited by propranolol and epinephrine; the (-) stereoisomers are at least 50-times more potent than the (+) stereoisomers. Binding of both radioligands is inhibited by adrenergic ligands with a potency order of propranolol much greater than isoproterenol greater than epinephrine greater than practolol greater than norepinephrine greater than phenylephrine. These observations indicate that [125I]CYP and [125I]HBP bind to platelet sites which have the pharmacological characteristics of beta-adrenergic receptors but which are not typical of either the beta 1 or beta 2 sub-type.


Assuntos
Plaquetas/metabolismo , Pindolol/análogos & derivados , Receptores Adrenérgicos beta/metabolismo , Receptores Adrenérgicos/metabolismo , Membrana Celular/metabolismo , Humanos , Radioisótopos do Iodo , Iodocianopindolol , Cinética , Pindolol/sangue
12.
Biochim Biophys Acta ; 714(3): 389-94, 1982 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-6120721

RESUMO

Several new clonidine analogs were synthesized and their ability to inhibit [3H]phentolamine binding to human platelet alpha 2-adrenergic receptors was tested. The order of potency and calculated dissociation constants for clonidine and its analogs were as follows: clonidine (0.020 +/- 0.005 microM) greater than p-aminoclonidine (0.100 +/- 0.010 microM) greater than hydroxy-phenacetyl-aminoclonidine (0.20 +/- 0.03 microM) greater than p-dansyl clonidine (1.00 +/- 0.20 microM) greater than t-boc-tyrosine clonidine (1.80 +/- 0.60 microM). Thus, p-amino substitution reduces alpha 2-adrenergic affinity in the platelet system. The effects of clonidine and its p-amino analogs on platelet adenylate cyclase were also evaluated. This enzyme is inhibited by epinephrine acting via alpha 2-adrenergic receptors. Both clonidine and p-aminoclonidine cause slight inhibition of basal adenylate cyclase and reverse the inhibition induced by epinephrine. These observations indicate that clonidine is a partial agonist for platelet alpha 2-adrenergic receptors.


Assuntos
Agonistas alfa-Adrenérgicos/sangue , Plaquetas/metabolismo , Clonidina/análogos & derivados , Clonidina/sangue , Receptores Adrenérgicos alfa/metabolismo , Receptores Adrenérgicos/metabolismo , Adenilil Ciclases/sangue , Epinefrina/farmacologia , Humanos , Cinética , Fentolamina/sangue
13.
Biochim Biophys Acta ; 672(3): 280-7, 1981 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-6163476

RESUMO

Protein carboxymethylase of mouse pancreas is both soluble (70%) and particulate (30%). The Km for S-adenosylmethionine is 7.5 x 10(-7) M and the Ki for S-adenosylethionine is 1.3 . 10(-5) M. Administration of an ethionine containing diet results in a decrease in protein carboxymethylase activity. Ethionine ingestion also increases pancreatic amylase content by interfering with digestive enzyme discharge. The reciprocal changes in amylase content and protein carboxymethylase activity can be detected within 12 h of commencing the ethionine administration and are enhanced by simultaneous choline deficiency. These studies support the hypothesis that protein carboxymethylase plays an important role in secretion of exportable material. Inhibition of pancreatic protein carboxymethylase activity in vivo may be one important mechanism by which ethionine interferes with digestive enzyme discharge.


Assuntos
Deficiência de Colina/metabolismo , Etionina/farmacologia , Pâncreas/enzimologia , Proteínas Metiltransferases/metabolismo , Proteína O-Metiltransferase/metabolismo , Adenosina/análogos & derivados , Adenosina/farmacologia , Amilases/metabolismo , Animais , Proteínas Alimentares/farmacologia , Etionina/análogos & derivados , Feminino , Camundongos , Pâncreas/efeitos dos fármacos , S-Adenosilmetionina/metabolismo
14.
Biochim Biophys Acta ; 757(2): 156-63, 1983 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-6303440

RESUMO

The relative influences of the in vivo administration of phenoxybenzamine on in vitro binding to alpha 1-adrenergic receptors and alpha 1-receptor-mediated responses were studied. Phenoxybenzamine treatment reduced maximal specific binding of the alpha 1-selective antagonist [3H]prazosin to liver cell membranes. This response was rapid (less than 90 min) and half-maximal following a phenoxybenzamine dose of approx. 10 mg/kg. A similar decrease in the ability of phenylephrine to stimulate glucose release and 45Ca2+ efflux from liver slices was also noted after phenoxybenzamine treatment. During the recovery period following administration of 30 mg/kg phenoxybenzamine, [3H]prazosin specific binding and phenylephrine-stimulated glucose release and 45Ca2+ efflux returned to their respective control levels with t 1/2 values of 42, 49 and 38 h, respectively. At all times studied during the recovery period, alpha 1-binding and both of the alpha 1-responses were similar fractions of their respective control values. These observations indicate that a close relationship exists between the density of [3H]prazosin binding sites and the ability of rat liver to respond to alpha 1-stimulation. We suggest that the binding sites identified in studies using the antagonist [3H]prazosin and those through which the agonist phenylephrine stimulates glucose release and 45Ca2+ efflux are either identical or in equilibrium with each other.


Assuntos
Fígado/metabolismo , Fenoxibenzamina/farmacologia , Prazosina/metabolismo , Quinazolinas/metabolismo , Receptores Adrenérgicos alfa/metabolismo , Receptores Adrenérgicos/metabolismo , Animais , Cálcio/metabolismo , Feminino , Glucose/metabolismo , Cinética , Fígado/efeitos dos fármacos , Fenilefrina/farmacologia , Ratos
15.
J Am Coll Cardiol ; 9(3): 524-30, 1987 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-3819199

RESUMO

In 103 patients who underwent placement of 106 percutaneous wire-guided intraaortic balloon catheters between August 1983 and January 1986, all placements were successful and the average duration of counterpulsation was 3.4 +/- 1.6 days. During counterpulsation, 45 patients developed limb ischemia that required premature balloon removal in 29 patients. The development of limb ischemia was significantly related to the presence of diabetes (risk ratio 2.0), peripheral vascular disease (risk ratio 1.9), female gender (risk ratio 1.8) and the presence of a postinsertion ankle-brachial pressure index less than 0.8 (risk ratio 7.9). There was no association between the development of limb ischemia and age, body surface area, balloon size (10.5F/12F) or adequacy of anticoagulation. Fifteen patients underwent vascular surgery for treatment of balloon-related limb ischemia, which was associated with one operative death. Nine patients had persistent limb ischemia (seven asymptomatic, two symptomatic) at the time of hospital discharge. Improvements in wire-guided balloon technology have increased the probability of successful balloon placement over that of surgical placement and have reduced the incidence of major aortic injury, but there is no evidence that these improvements have reduced the incidence of limb ischemia or its sequelae. This should be borne in mind before proceeding with balloon insertion in patients with one or more risk factors for developing limb ischemia.


Assuntos
Cateterismo/efeitos adversos , Extremidades/irrigação sanguínea , Balão Intra-Aórtico/efeitos adversos , Isquemia/etiologia , Idoso , Cateterismo/métodos , Feminino , Humanos , Balão Intra-Aórtico/instrumentação , Balão Intra-Aórtico/métodos , Isquemia/terapia , Masculino , Pessoa de Meia-Idade , Alta do Paciente
16.
Br J Pharmacol ; 75(1): 213-7, 1982 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-6280800

RESUMO

1 The synthesis of several butyrophenone analogues of haloperidol is described. 2 The effects of these compounds on alpha-adrenoceptors were evaluated by examining their ability to reduce alpha 1-stimulated K+ release from rat parotid slices and to displace [3H]-phentolamine from human platelet membrane alpha 2-adrenoceptors. 3 The affinity of haloperidol and its analogues for alpha 1-receptors was found to be 1 to 2 orders of magnitude greater than that for alpha 2-adrenoceptors. These observations suggest that most of the alpha-adrenoceptor activity of butyrophenones results from their interaction with alpha 1-adrenoceptors. 4 The relatively high affinity of the butyrophenones for alpha 1-adrenoceptors suggests that they may be useful as probes in studies of alpha 1-adrenoceptors in these and other tissues.


Assuntos
Plaquetas/metabolismo , Haloperidol/análogos & derivados , Glândula Parótida/metabolismo , Receptores Adrenérgicos alfa/efeitos dos fármacos , Receptores Adrenérgicos/efeitos dos fármacos , Animais , Membrana Celular/metabolismo , Haloperidol/síntese química , Haloperidol/farmacologia , Humanos , Técnicas In Vitro , Fentolamina/metabolismo , Potássio/metabolismo , Ratos , Receptores Adrenérgicos alfa/metabolismo
17.
Biochem Pharmacol ; 34(5): 623-9, 1985 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-2983731

RESUMO

Sucrose feeding has been shown previously to alter the plasma concentration of several factors which may regulate beta-adrenergic receptors, including corticosteroids and insulin as well as altered sympathetic nervous system (SNS) tone. For this reason we initiated a study of the effects of sucrose feeding on the beta-adrenergic receptor-adenylate cyclase system in rat liver plasma membranes. Beta-Adrenergic responsiveness was monitored by measuring isoproterenol stimulation of adenylate cyclase activity, while beta-adrenergic receptor characteristics were evaluated by analyzing [125I]iodocyanopindolol [( 125I]CYP) binding. Rats fed rat chow ad lib. supplemented by drinking water containing 10% sucrose solution exhibited a 50-75% reduction in hepatic isoproterenol-sensitive adenylate cyclase activity. This effect of sucrose was also observed in adrenalectomized (ADX) and 6-hydroxydopamine-pretreated animals, ruling out a causal role for corticosteroids or the sympathetic nervous system respectively. No effect was observed on basal, glucagon-, fluoride- or GTP-stimulated adenylate cyclase. A small but significant decrease in [125I]CYP specific binding capacity was observed in liver membranes prepared from sucrose-fed ADX rats, whereas no change in [125I]CYP binding capacity was observed in in sucrose-fed normal rats. These observations suggest that beta-receptor to adenylate cyclase coupling efficiency is decreased by the sucrose diet. The activities of two membrane-associated phospholipid methyltransferases and the content of endogenous S-adenosylmethionine in liver were reduced by sucrose feeding, implying a defect in the methylation pathway for phosphatidylcholine synthesis. The possible relationship between this latter finding and the observed decrease in beta-adrenergic receptor to adenylate cyclase coupling efficiency is discussed.


Assuntos
Adenilil Ciclases/metabolismo , Fígado/enzimologia , Receptores Adrenérgicos beta/efeitos dos fármacos , Sacarose/farmacologia , Animais , Membrana Celular/enzimologia , Feminino , Técnicas In Vitro , Iodocianopindolol , Isoproterenol/farmacologia , Fluidez de Membrana , Metilação , Fosfolipídeos/metabolismo , Pindolol/análogos & derivados , Pindolol/metabolismo , Ratos , Ratos Endogâmicos , Receptores Adrenérgicos beta/metabolismo
18.
Surgery ; 79(4): 414-20, 1976 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1257905

RESUMO

Six patients with massive pyloroduodenal hemorrhage were treated by selective embolization of retracted autologous clot to occlude the bleeding vessels. All patients had severe associated illnesses and were very poor candidates for operative treatment. The actively bleeding vessel was occluded successfully and hemorrhage was controlled with autologous clot alone in five of these patients, although two patients later bled from other sites. Although three patients died, none died as a direct result of bleeding. The only complication encountered, multiple small hepatic infarct, occurred when the embolized clot migrated from the gastroduodenal artery to the hepatic artery. A method of avoiding this complication is presented. Selective emolization of retracted autologous clot represents a useful alternative to the operative management of massive pyloroduodenal hemorrhage and should be considered for the treatment of patients whose associated diseases make them poor candidates for operative treatment.


Assuntos
Úlcera Duodenal/complicações , Embolização Terapêutica/métodos , Úlcera Péptica Hemorrágica/terapia , Úlcera Gástrica/complicações , Adulto , Idoso , Angiografia , Retração do Coágulo , Duodeno/irrigação sanguínea , Embolização Terapêutica/efeitos adversos , Feminino , Artéria Hepática , Humanos , Masculino , Pessoa de Meia-Idade , Úlcera Péptica Hemorrágica/diagnóstico por imagem , Estômago/irrigação sanguínea
19.
Surgery ; 87(6): 714-6, 1980 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7376083

RESUMO

A prominent or edematous papilla of Vater may prodce a rounded filling defect in the duodenum. During T tube or operative cholangiography, this may simulate a calculus impacted in the distal or intramural portion of the common bile duct. This communication reports such an occurrence. Recognition of this potential cause for a false positive cholangiogram should prevent some instances of unnecessary instrumentation of the common bile duct.


Assuntos
Ampola Hepatopancreática/diagnóstico por imagem , Doenças do Ducto Colédoco/diagnóstico por imagem , Edema/diagnóstico por imagem , Cálculos Biliares/diagnóstico por imagem , Idoso , Doenças do Ducto Colédoco/etiologia , Diagnóstico Diferencial , Edema/complicações , Feminino , Humanos , Radiografia
20.
Surgery ; 85(4): 372-6, 1979 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-311956

RESUMO

Gastrointestinal bleeding remains a major diagnostic problem, and the commonly employed techniques of contrast radiography, endoscopy, and arteriography may not successfully localize the site and/or define the cause of gastrointestinal hemorrhage. Technetium-99m pertechnetate scanning has been useful in identifying Meckel's diverticula, and modifications of this technique may successfully identify highly vascular lesions responsible for gastrointestinal bleeding. A patient with recurrent hemorrhage from a leiomyosarcoma of the ileum is described. The lesion was identified with flow studies and immediate static imaging after injection of technetium-99m pertechnetate. In addition, the lesion was demonstrated by scanning using in vivo technetium-99m pertechnetate labelled autologous erythrocytes. The potential value of these scanning techniques as noninvasive tools for the localization and identification of lesions responsible for gastrointestinal bleeding is discussed.


Assuntos
Hemorragia Gastrointestinal/diagnóstico por imagem , Intestino Delgado , Idoso , Humanos , Íleo , Neoplasias Intestinais/complicações , Intestino Delgado/diagnóstico por imagem , Leiomiossarcoma/complicações , Masculino , Cintilografia , Recidiva , Tecnécio
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