Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 37
Filtrar
1.
Rev Med Suisse ; 11(494): 2104, 2106-9, 2015 Nov 11.
Artigo em Francês | MEDLINE | ID: mdl-26727730

RESUMO

Urinary incontinence (UI) is frequent in older women but remains often neglected when they consult their physician. It is associated with numerous health and social consequences that impact on these older persons' quality of life, as well as on their health care costs. Primary care physicians should become more familiar with this frequent condition. A clinical pathway is proposed to guide them in diagnosing and managing of this debilitating condition.


Assuntos
Medicina Geral , Incontinência Urinária/terapia , Idoso , Feminino , Humanos
2.
Surgery ; 145(2): 147-56, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19167969

RESUMO

BACKGROUND: The role of polymorphonuclear neutrophil granulocytes (PMNs) and the PMN-derived protease, which is called matrix metalloproteinase-9 (MMP-9), for the gut barrier dysfunction in severe acute pancreatitis (SAP) has not yet been clarified. The aim of this study was to evaluate the effects of PMNs and MMP-9 on gut barrier dysfunction in rat SAP. METHODS: SAP was induced by the injection of 5% sodium taurocholate, and anti-rat PMN serum or BB-94 were administered 48 h and 24 h, respectively, before the induction of acute pancreatitis. Twenty-four hours after the induction of acute pancreatitis, the gut barrier dysfunction and the incidence of bacterial translocation (BT) and PMN transmigration were investigated by bacterial, histologic, and biochemical (MPO) analysis. Inhibition of MMP-9 was achieved by depletion of PMNs or inhibition of MMP-activity by a broad-spectrum MMP inhibitor and confirmed by zymography. In addition, reactive oxygen species were evaluated by spin trap assay. RESULTS: The mucosal injury and the infiltration of PMNs into the gut tissue of rats with SAP were significantly increased in comparison with rats treated with anti-rat PMN serum or BB-94. The levels of MMP-9 and reactive oxygen species in the gut of rats with SAP were significantly higher than those of the rats treated with anti-rat PMN serum or BB-94. Pretreatment with anti-rat PMN serum or BB-94 reduced the incidence of BT in SAP. CONCLUSION: The incidence of BT in SAP was prevented by the depletion of PMNs or less pronounced by the injection of the MMP inhibitor BB-94. PMNs play an important pathophysiologic role in the occurrence of BT, and MMP-9 is involved in both BT and PMN transmigration in rat SAP.


Assuntos
Translocação Bacteriana , Doenças do Íleo/imunologia , Metaloproteinase 9 da Matriz/metabolismo , Neutrófilos/enzimologia , Pancreatite Necrosante Aguda/complicações , Animais , Doenças do Íleo/enzimologia , Doenças do Íleo/patologia , Doenças do Íleo/prevenção & controle , Íleo/imunologia , Íleo/patologia , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Inibidores de Metaloproteinases de Matriz , Naftol AS D Esterase , Infiltração de Neutrófilos , Pâncreas/patologia , Pancreatite Necrosante Aguda/enzimologia , Pancreatite Necrosante Aguda/imunologia , Pancreatite Necrosante Aguda/patologia , Peroxidase/análise , Fenilalanina/análogos & derivados , Fenilalanina/uso terapêutico , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Ácido Taurocólico , Tiofenos/uso terapêutico
3.
Dalton Trans ; (31): 3378-89, 2007 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-17664974

RESUMO

Metal-free 5,10,15,20-tetraferrocenylporphyrin and 5,10-bisferrocenyl-15,20-bisphenylporphyrin have been prepared and characterized by UV-Vis, MCD, (1)H, (13)C, and variable-temperature NMR, APCI- and ESI-MS, and Mössbauer spectroscopy, while their redox properties were investigated using electrochemical (cyclic voltammetry and differential pulse voltammetry), spectroelectrochemical, and chemical oxidation approaches. The electronic structure calculations at Density Functional Theory level reveal that both compounds adopt saddle conformations and the HOMOs in both complexes are predominantly metal-centered, while the LUMOs predominantly consist of porphyrin pi* orbitals. In spite of the rotational freedom of ferrocenyl substituents at room temperature, both metal-free 5,10,15,20-tetraferrocenylporphyrin and 5,10-bisferrocenyl-15,20-bisphenylporphyrin are able to form mixed-valence states upon the successive ferrocene-based two- and one-electron oxidations, respectively, as confirmed by UV-Vis, MCD, Mössbauer, electro-, and spectroelectrochemical methods, and thus, the earlier suggested (Boyd et al. Chem. Commun., 1999, 637) requirements for the formation of mixed-valence states in ferrocene-containing porphyrins should be revised.

4.
Am J Surg ; 189(2): 214-8, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15720994

RESUMO

BACKGROUND: The overall long-term results of medical treatment for morbid obesity are poor. Surgery is the only treatment option to obtain long-term weight reduction. Analysis of risk factors for treatment success of laparoscopically placed gastric banding (LGB) has not been available until now. METHODS: Prospective study with 99 patients with LGB between January 1997 and July 2003. The parameters assessed as risk factors included onset of obesity, feeling of postprandial satiety, and initial body mass index (BMI). RESULTS: Median follow-up was 36 months (3 to 72). Independent prognostic factors of excess body weight reduction (>25%) were for the first postoperative year: onset of obesity as an adolescent (relative risk [RR] 0.21), an initial BMI <45 kg/m(2) (RR 4.76), and a BMI between 45.1 and 50 kg/m(2) (RR 3.23). After the second year, independent prognostic factors were as follows: feeling of postprandial satiety (RR 5.26) and an initial BMI <45 kg/m(2) (RR 3.03). CONCLUSION: LGB is suitable to achieve intermediate weight reduction in patients with morbid obesity. To obtain the best results, patients should be treated before they achieve a BMI >45 kg/m(2). Additionally a postprandial feeling of satiety after LGB is mandatory for good long-term results.


Assuntos
Gastroplastia/efeitos adversos , Gastroplastia/métodos , Laparoscopia/efeitos adversos , Obesidade Mórbida/complicações , Complicações Pós-Operatórias , Adulto , Idoso , Índice de Massa Corporal , Peso Corporal , Feminino , Humanos , Laparoscopia/métodos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Seleção de Pacientes , Prognóstico , Estudos Prospectivos , Fatores de Risco , Resultado do Tratamento , Redução de Peso
6.
Nitric Oxide ; 7(2): 103-8, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12223179

RESUMO

We report that NaON=N(O)-X-N(O)=NONa (1), where X is para-disubstituted benzene, hydrolyzes to 2 mol of nitric oxide (NO) with concurrent production of 1 mol of p-benzoquinone dioxime at physiological pH. The reaction is acid catalyzed, with a rate that slows as the substrate concentration is increased. The results demonstrate that a carbon-bound diazeniumdiolate can be quantitatively hydrolyzed to produce NO as the only gaseous nitrogen-containing product. The data also suggest that N-N bond cleavage is the rate-determining step in NO release, since C-N cleavage followed by dissociation of O=N-N=O to two NO molecules cannot be operative in this case. The finding that this oxime can absorb NO in organic media and regenerate it quantitatively at physiological pHs extends the potential pharmacological implications of the carbon-bound diazeniumdiolates.


Assuntos
Compostos Azo/química , Carbono/química , Óxido Nítrico/química , Catálise , Gases/química , Meia-Vida , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Medições Luminescentes , Estrutura Molecular
7.
Invest Ophthalmol Vis Sci ; 43(6): 1820-7, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12036985

RESUMO

PURPOSE: To determine the distribution of CYP1B1 gene mutations in Brazilian patients with primary congenital glaucoma (PCG). METHODS: PCG diagnosis was established by presence of buphthalmos in at least one affected eye and associated high intraocular pressures before the age of 3 years. CYP1B1 mutation screening of 52 patients with PCG was performed by SSCP and direct sequencing of PCR fragments. RESULTS: Eleven mutations, four of which are novel, were observed in 26 (50%) individuals. A new frameshift mutation (4340delG) was observed in 20.2% of all individuals screened. These individuals had early-onset, bilateral glaucoma that necessitated multiple surgical interventions. CYP1B1 mutations were twice as frequent in affected individuals of European descent as in individuals of African descent. Analysis of six intragenic single nucleotide polymorphisms (SNPs) established 5'-C-C-G-G-T-A-3' as the most common haplotype among the affected Brazilian individuals. A nonsense mutation (W57X) previously reported in an individual with Peters anomaly (compound heterozygote) was also observed in two individuals with PCG but combined with different mutations. A newly developed SSCP assay enabled us to detect all DNA mutations and polymorphisms previously detected by direct sequencing. CONCLUSIONS: Our results indicate that CYP1B1 mutations may be responsible for half of cases of PCG in the Brazilian population. The SNP haplotype 5'-C-C-G-G-T-A-3' was associated with the majority of CYP1B1 mutations. This haplotype harbors the high-activity V432 allele, which is emerging as a putative susceptibility factor in several cancers.


Assuntos
Hidrocarboneto de Aril Hidroxilases , Sistema Enzimático do Citocromo P-450/genética , Glaucoma/congênito , Glaucoma/enzimologia , Mutação , Brasil , Pré-Escolar , Citocromo P-450 CYP1B1 , Análise Mutacional de DNA , Primers do DNA/química , Glaucoma/etnologia , Haplótipos , Humanos , Lactente , Recém-Nascido , Pressão Intraocular , Biologia Molecular , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único , Polimorfismo Conformacional de Fita Simples , Acuidade Visual
8.
Org Lett ; 4(8): 1323-5, 2002 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-11950353

RESUMO

Acetonitrile, frequently used as a solvent in reactions of nitric oxide (NO) with amines and other nucleophiles to introduce the [N(O)NO](-) (diazeniumdiolate) functional group, has itself been shown to react with NO in the presence of strong base to yield methane trisdiazeniumdiolate (1), presumably via an intermediate trisdiazeniumdiolated imidate. Aqueous hydrolysis of 1 does not follow simple first-order kinetics and produces mixtures of NO and nitrous oxide in ratios that vary with solution pH. [reaction: see text]


Assuntos
Acetonitrilas/química , Óxido Nítrico/química , Compostos Azo/química , Indicadores e Reagentes , Cinética , Espectroscopia de Ressonância Magnética , Padrões de Referência , Solventes , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta
9.
Child Abuse Negl ; 25(8): 1001-14, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11601594

RESUMO

OBJECTIVE: The Trauma Symptom Checklist for Young Children (TSCYC) is a 90-item caretaker-report measure of children's trauma- and abuse-related symptomatology. It contains two reporter validity scales and eight clinical scales [Post-traumatic Stress-Intrusion (PTS-I), Post-traumatic Stress-Avoidance (PTS-AV), Post-traumatic Stress-Arousal (PTS-AR), Post-traumatic Stress-Total (PTS-TOT), Sexual Concerns (SC), Dissociation (DIS), Anxiety (ANX), Depression (DEP), and Anger/Aggression (ANG)], as well as an item assessing hours per week of caretaker contact with the child. This paper introduces the TSCYC and describes its psychometric properties in a multisite validity study. METHOD: A total of 219 TSCYCs administered by six clinician/researchers across the United States were analyzed for scale reliability and association with several types of childhood maltreatment. RESULTS: The TSCYC clinical scales have good reliability and are associated with exposure to childhood sexual abuse, physical abuse, and witnessing domestic violence. The PTS-I, PTS-AV, PTS-AR, and PTS-TOT scales were most predictive, followed by SC in the case of sexual abuse and DIS in the case of physical abuse. There were a small number of age, sex, and race effects on TSCYC scores. CONCLUSIONS: The TSCYC appears to have reasonable psychometric characteristics, and correlates as expected with various types of trauma exposure. Subject to continued validation and the development of general population norms, its use as a clinical measure is supported.


Assuntos
Maus-Tratos Infantis/psicologia , Escalas de Graduação Psiquiátrica , Transtornos de Estresse Pós-Traumáticos/classificação , Ira , Criança , Pré-Escolar , Depressão , Feminino , Indicadores Básicos de Saúde , Humanos , Masculino , Pais , Análise de Regressão , Reprodutibilidade dos Testes , Autorrevelação , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Estados Unidos
11.
J Invest Dermatol ; 97(2): 230-9, 1991 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-1649228

RESUMO

Increasing evidence suggests an immunoregulatory function of the potent steroid hormone 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) which has been successfully applied for treatment of psoriasis. The skin is both a site of production and a target of 1,25(OH)2D3. In vitro, 1,25(OH)2D3 inhibits proliferation and stimulates differentiation of keratinocytes. We investigated the in situ expression of vitamin D-receptors (VDR) in normal and psoriatic skin by immunochemical methods. The VDR were visualized using the monoclonal antibody (MoAb) 9A7g to the VDR and the labeled avidinbiotin technique. Immunoreactivity was consistently confined to nuclei in all skin biopsies. In normal skin specimens (n = 10) VDR antigens were expressed in keratinocytes of all epidermal layers (except those of the stratum corneum) and in cells of the epidermal appendages. Double labeling experiments with MoAb to cluster-defined antigens indicated that melanocytes and approximately 75% of Langerhans cells exhibit 1,25(OH)2D3 receptors in normal skin biopsies (n = 5). Depending on their localization in skin compartments 42-62% of CD11b+ positive macrophages and 45-75% of CD3+ T lymphocytes expressed VDR. Non-lesional psoriatic skin specimens (n = 8) revealed nearly identical staining patterns. Lesional psoriatic skin specimens (n = 8) exhibited a significant increase of VDR expression both in basal and suprabasal epidermal layers as measured by computer-assisted morphometry and showed a remarkable change of the immune cell pattern: the densitity and proportion of VDR positive T lymphocytes and macrophages were higher in the epidermal and the perivascular papillary loop compartment. These in vivo findings strongly support the hypothesis that 1,25(OH)2D3 modulates immune response and cell proliferation/differentiation in human skin.


Assuntos
Psoríase/metabolismo , Receptores de Esteroides/metabolismo , Pele/ultraestrutura , Adulto , Anticorpos Monoclonais/metabolismo , Avidina/metabolismo , Biotina/metabolismo , Epiderme/metabolismo , Humanos , Imuno-Histoquímica , Imunofenotipagem , Psoríase/patologia , Receptores de Calcitriol , Receptores de Esteroides/fisiologia , Pele/citologia , Pele/metabolismo
12.
Respir Physiol ; 79(3): 279-91, 1990 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2356364

RESUMO

To study the distribution of oxidative capacity in the cardiac myocyte in control and in hypermetabolic (hyperthyroid) rats, we evaluated mitochondrial volume density (Vv,mi) distribution by morphometry and oxidative capacity, cytochrome a + a3 concentration and protein yield of isolated subsarcolemmal and interfibrillar mitochondria by biochemical techniques. In control animals Vv,mi underneath the sarcolemma was higher than in the center of the myocytes and it decreased linearly with increasing distance from the capillaries. Interfibrillar mitochondria showed a greater oxidative capacity and a high concentration of cytochrome a + a3 than subsarcolemmal mitochondria. Values of Vv,mi and its distribution were not changed by the hypermetabolic condition. Oxidative capacity and cytochrome a + a3 concentration were higher in the interfibrillar mitochondria but not in the subsarcolemmal mitochondria of the hypermetabolic rats. The product of the oxidative capacity of the mitochondria times the Vv,mi indicated that the oxidative capacity of the interfibrillar zone is 30% higher than that of the subsarcolemmal zone. In the hypermetabolic rats, due to the increase in oxidative capacity of the interfibrillar mitochondria, the oxidative capacity of this zone was 80% higher than that of the subsarcolemmal zone.


Assuntos
Metabolismo Energético/fisiologia , Miocárdio/citologia , Animais , Metabolismo Energético/efeitos dos fármacos , Feminino , Coração/fisiologia , Injeções , Mitocôndrias Cardíacas/metabolismo , Mitocôndrias Cardíacas/fisiologia , Mitocôndrias Cardíacas/ultraestrutura , Miocárdio/metabolismo , Oxirredução , Ratos , Ratos Endogâmicos , Hormônios Tireóideos/administração & dosagem
13.
Z Hautkr ; 62(13): 978-82, 1987 Jul 01.
Artigo em Alemão | MEDLINE | ID: mdl-3630301

RESUMO

With regard to the frequent alterations of insulin secretion and glucose tolerance in psoriatic patients, the birth weights of children of 100 psoriatic mothers were compared with the birth weights of children of 100 carefully matched control mothers. The mean birth weight in the psoriatic group was 140 g higher than that of the control group. A birth weight of more than 4,000 g was observed in the children of 20.4% of the psoriatic mothers and in only 11.3% in the control group. The frequency of diabetes mellitus independent of insulin (type II) in psoriasis recalls the hypothesis of the "thrifty" genotype, which suggests an explanation for the high incidence of diabetes in modern societies. On the basis of our results, this hypothesis may also be applied to psoriasis. In addition, we studied the influence of pregnancy on the course of psoriasis. Improvement was noted in 27.8% (complete remission in 20%), exacerbation in 14.7%; in 46.6% the disease remained unchanged.


Assuntos
Evolução Biológica , Peso ao Nascer , Complicações na Gravidez/fisiopatologia , Psoríase/fisiopatologia , Feminino , Genótipo , Humanos , Recém-Nascido , Gravidez , Complicações na Gravidez/genética , Psoríase/genética
14.
J Biol Chem ; 259(13): 8529-33, 1984 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-6736041

RESUMO

In heme-deficient reticulocyte lysates, protein synthesis initiation is inhibited due to the activation of a heme-regulated protein kinase which blocks protein synthesis by the specific phosphorylation of the alpha-sub-unit of eukaryotic initiation factor 2 (eIF-2 alpha). The restoration of synthesis requires both hemin and glucose-6-P (Ernst, V., Levin, D. H., and London, I. M. (1978) J. Biol. Chem. 253, 7163-7172). The sugar phosphate fulfills two functions in initiation: (i) the generation of NADPH, and (ii) an effector function in some step in initiation. This latter effect is readily demonstrated in lysates depleted of low molecular weight components by filtration in dextran gels. In gel-filtered lysates, linear protein synthesis is sustained only by the addition of both hemin (20 microM) and glucose-6-P (or 2-deoxyglucose-6-P) (50-500 microM). The omission of either component gives rise to inhibitions which are characterized by the activation of heme-regulated eIF-2 alpha kinase and the concomitant phosphorylation of both endogenous heme-regulated eIF-2 alpha kinase and endogenous eIF-2 alpha, indicating that glucose-6-P is involved in the regulation of heme-regulated eIF-2 alpha kinase. In support of this, we find (a) that gel-filtered lysates incubated with hemin but depleted of glucose-6-P produce sufficient heme-regulated eIF-2 alpha kinase to inhibit protein synthesis when mixed with normal hemin-supplemented lysates; (b) the inhibitions of protein synthesis produced by heme-regulated eIF-2 alpha kinase generated either in glucose-6-P-depleted lysates or heme-deficient lysates are reversed by added eIF-2; and (c) the eIF-2 alpha kinase activities formed in the absence of either hemin or glucose-6-P are both neutralized by an anti-heme-regulated eIF-2 alpha kinase antiserum. We conclude that the physiological activation of heme-regulated eIF-2 alpha kinase is controlled by both hemin and glucose-6-P.


Assuntos
Glucofosfatos/farmacologia , Heme/farmacologia , Proteínas Quinases/metabolismo , Reticulócitos/enzimologia , Animais , Cromatografia em Gel , Ativação Enzimática , Glucose-6-Fosfato , Cinética , Biossíntese de Proteínas/efeitos dos fármacos , Proteínas Quinases/isolamento & purificação , Coelhos , eIF-2 Quinase
15.
Biochem Biophys Res Commun ; 114(3): 1089-96, 1983 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-6311196

RESUMO

Previous studies indicated that the species of type 1 and type 2 protein phosphatases (PP-1, PP-2) in rabbit reticulocytes are similar to those of rabbit skeletal muscle and rabbit liver. Reticulocyte PP-1 was found to be selectively inhibited by the heat stable protein phosphatase inhibitor-2 (I-2) from rabbit skeletal muscle. Of interest was the observation that muscle I-2 appeared to regulate protein synthesis in reticulocyte lysates by inhibiting an eIF-2 alpha phosphatase with type 1 properties. In this study we have characterized reticulocyte inhibitor-2 (I-2) and find that its properties are similar to those of skeletal muscle I-2. (i) Both I-2 species are stable to boiling and to acid treatment, and have similar chromatographic profiles on DEAE-cellulose and on Blue Sepharose CL-6B. (ii) The two I-2 species migrate electrophoretically as 26-28,000 dalton polypeptides in SDS-acrylamide gels. (iii) Both skeletal muscle I-2 and reticulocyte I-2 selectively inhibit isolated reticulocyte PP-1 and endogenous PP-1 in the lysate. (iv) Reticulocyte I-2 co-chromatographs with PP-1 on DEAE-cellulose, and over 90% of lysate I-2 can be isolated from this partially purified PP-1. (v) Both inhibitor-2 species are active in the unphosphorylated state, but upon addition to lysates, both are phosphorylated by endogenous cAMP-independent protein kinase(s). In addition a preliminary analysis using a polyclonal antibody against muscle inhibitor-1 confirmed biochemical analyses which indicate that lysates are deficient in inhibitor-1.


Assuntos
Inibidores Enzimáticos/sangue , Fosfoproteínas Fosfatases/antagonistas & inibidores , Fosfoproteínas Fosfatases/sangue , Proteínas , Reticulócitos/enzimologia , Animais , Peso Molecular , Coelhos
16.
Biochem Biophys Res Commun ; 114(1): 41-9, 1983 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-6882432

RESUMO

Double-stranded RNA (dsRNA) inhibits protein synthesis initiation in rabbit reticulocyte lysates by the activation of a latent dsRNA-dependent cAMP-independent protein kinase which phosphorylates the alpha-subunit of the eukaryotic initiation factor eIF-2. In this study, we describe a dsRNA-like component which is present in preparations of HeLa mRNA (poly A+) isolated from total cytoplasmic RNA. The inhibitory species in the HeLa cytoplasmic mRNA was detected by (a) its ability to inhibit protein synthesis with biphasic kinetics in reticulocyte lysates translating endogenous globin mRNA, and (b) by the inefficient translation of HeLa cytoplasmic mRNA in a nuclease-treated mRNA-dependent reticulocyte lysate. The inhibitory component was characterized as dsRNA by several criteria including (i) the ability to activate the lysate dsRNA-dependent eIF-2 alpha kinase (dsI); (ii) the prevention of both dsI activation and inhibition of protein synthesis by high levels of dsRNA or cAMP; (iii) the reversal of inhibition by eIF-2; and (iv) the inability to inhibit protein synthesis in wheat germ extracts which lack latent dsI. By the same criteria, the putative dsRNA component(s) appears to be absent from preparations of HeLa mRNA isolated exclusively from polyribosomes.


Assuntos
Globinas/genética , Biossíntese de Proteínas/efeitos dos fármacos , RNA de Cadeia Dupla/genética , RNA Mensageiro/genética , Reticulócitos/metabolismo , Animais , Proteínas Sanguíneas , Citosol/metabolismo , Fator de Iniciação 2 em Eucariotos , Células HeLa/metabolismo , Humanos , Cinética , Fatores de Iniciação de Peptídeos/sangue , Proteínas Quinases/sangue , Coelhos , Ribossomos/metabolismo
17.
J Biol Chem ; 258(3): 1439-43, 1983 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-6296096

RESUMO

Protein phosphatase type 1 and type 2 activities (designated PP-1 and PP-2, respectively) from rabbit reticulocyte lysates have been identified and characterized based on criteria previously established for similar activities in rabbit skeletal muscle and rabbit liver. These include (a) chromatographic separation on DEAE-cellulose, (b) substrate specificity toward glycogen phosphorylase a and the alpha- and beta-subunits of phosphorylase kinase, (c) differential sensitivity to the heat-stable protein phosphatase inhibitors-1 and -2, and (d) sensitivity to MgATP. When total lysate phosphatases are assayed in the presence of 1 mM MnCl2, protein phosphatase type 2 represents 84% of lysate phosphorylase phosphatase activity. However, when phosphatase assays are carried out with MgATP concentrations similar to those in the lysate, type 2 activity is diminished, and the levels of type 1 (41%) and type 2 (59%) phosphatase activities are comparable. A small proportion (6%) of total lysate phosphatase is tightly bound to the ribosomes, where type 1 phosphatase predominates. At least five species of protein phosphatases can be identified in lysates. These constitute two forms of protein phosphatase type 1, one of which (designated FC) is dependent on MgATP and a lysate activator protein FA; both FC and FA have been identified previously in skeletal muscle. Three species of protein phosphatase type 2 have been identified and designated PP-2B, PP-2A1, and PP-2A2 based on criteria recently established for rabbit skeletal muscle and rabbit liver phosphatases, which display similar phosphatase profiles. Lysate protein phosphatases types 1, FC, 2A1, and 2A2 can all act on phosphorylase a and the alpha- (type 2) or beta-(type 1) subunit of phosphorylase kinase. PP-2B, a Ca2+/calmodulin-dependent phosphatase, specifically dephosphorylates the alpha-subunit of phosphorylase kinase, but does not act on phosphorylase alpha. The heat-stable protein phosphatase inhibitor-2 from skeletal muscle completely blocks the activity of the two type 1 phosphatases (PP-1, FC), but has no effect on the three species of type 2 protein phosphatase. A preliminary assay of the two heat-stable phosphatase inhibitors in lysates indicates significant levels of inhibitor-2, but little or no detectable inhibitor-1.


Assuntos
Isoenzimas/sangue , Proteínas Quinases/sangue , Reticulócitos/enzimologia , Animais , Isoenzimas/isolamento & purificação , Cinética , Fosfoproteínas Fosfatases/sangue , Fosforilase Fosfatase/sangue , Inibidores de Proteínas Quinases , Proteínas Quinases/isolamento & purificação , Coelhos , Especificidade por Substrato
18.
Proc Natl Acad Sci U S A ; 79(23): 7092-6, 1982 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-6296814

RESUMO

Reticulocyte lysates contain two major classes of protein phosphatase activities, designated type 1 and type 2. These designations are based on criteria derived from the analyses of protein phosphatase species in other tissues. The criteria include (i) chromatographic elution profiles on DEAE-cellulose; (ii) specificity of lysate phosphatases toward [(32)P]phosphorylase a and [(32)P]phosphorylase kinase; (iii) sensitivity of lysate phosphatases to Mg(2+) ATP; and (iv) sensitivity to the heat-stable protein phosphatase inhibitor-2. The lysate phosphatase species are similar to those described in rabbit skeletal muscle and rabbit liver. Reticulocyte protein phosphatase type 1, but not type 2, is inhibited by heat-stable protein phosphatase inhibitor-1 and -2 which have been characterized from rabbit skeletal muscle. We have initiated a study on the function and specificity of lysate protein phosphatase activities involved in the regulation of protein synthesis by examining the effects of protein phosphatase inhibitor-2 on reticulocyte protein synthesis and protein phosphorylation. Our findings are as follows. (a) Protein phosphatase inhibitor-2 inhibits protein chain initiation in hemin-supplemented lysates. (b) Inhibition is characterized by biphasic kinetics and is reversed by the delayed addition of purified reticulocyte eukaryotic initiation factor 2 (eIF-2). (c) Inhibition of protein synthesis by inhibitor-2 is accompanied by the phosphorylation of the alpha-subunit (38,000 daltons) of eIF-2 (eIF-2alpha) and of two heat-stable polypeptides of 29,000 and 44,000 daltons. (d) The 29,000-dalton component is phosphorylated in lysates under conditions of protein synthesis and appears to be inhibitor-2, but the physiological significance of this modification of inhibitor-2 is not clear. (e) Inhibitor-2 has no effect on the activation in vitro of isolated heme-regulated or double-stranded RNA-dependent eIF-2alpha kinases. We propose that the inhibition of protein synthesis in hemin-supplemented lysates by added inhibitor-2 is due at least in part to the inhibition of a type 1 eIF-2alpha phosphatase activity, which permits a basal eIF-2alpha kinase activity to be expressed leading to the accumulation of phosphorylated eIF-2alpha and an inhibition of protein synthesis.


Assuntos
Fatores de Iniciação de Peptídeos/metabolismo , Fosfoproteínas Fosfatases/antagonistas & inibidores , Biossíntese de Proteínas , Proteínas Quinases/metabolismo , Proteínas/metabolismo , Reticulócitos/fisiologia , Trifosfato de Adenosina/metabolismo , Animais , Sistema Livre de Células , Fator de Iniciação 2 em Eucariotos , Músculos/enzimologia , Iniciação Traducional da Cadeia Peptídica , Fosforilação , Coelhos , eIF-2 Quinase
19.
Rofo ; 134(6): 674-7, 1981 Jun.
Artigo em Alemão | MEDLINE | ID: mdl-6454631

RESUMO

The clinically most important disturbance of the function of esophagus is that of esophago-gastric area. Because there is up till now no recognized opinion about the mechanism of the esophago-gastric sphincter, there are a lot of theories about that. In our own radiologic studies of the esophagus we were able to demonstrate in a low percentage the intern muscularis mucosae. The structure of these intern folds of the muscularis mucosae are like a spiral line or a screw, this is in accordance with the direction of muscle bundles of the theories of "Muscular Stretch Closure Function of the Terminal Esophagus".


Assuntos
Esofagoplastia/métodos , Refluxo Gastroesofágico/diagnóstico por imagem , Adulto , Idoso , Junção Esofagogástrica/diagnóstico por imagem , Feminino , Refluxo Gastroesofágico/cirurgia , Hérnia Hiatal/diagnóstico por imagem , Hérnia Hiatal/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Liso/diagnóstico por imagem , Radiografia
20.
Proc Natl Acad Sci U S A ; 77(3): 1286-90, 1980 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-6929486

RESUMO

The site specificity of phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF-2alpha) by the heme-regulated and double-stranded RNA-activated eIF-2alpha kinases were compared by phosphopeptide mapping. eIF-2alpha was maximally phosphorylated in vitro with [gamma-(32)P]ATP and either crude or partially purified preparations of the kinases. (32)P-Labeled eIF-2alpha was isolated by electrophoresis in sodium dodecyl sulfate/polyacrylamide gels. The fixed, stained, and dried polypeptide band was excised and then exhaustively digested directly in the gel slice with one of several proteases (trypsin, chymotrypsin, subtilisin, or thermolysin); the resultant [(32)P]phosphopeptides were analyzed by one-dimensional chromatography or by two-dimensional chromatography and high-voltage electrophoresis. In addition, limited proteolysis of [(32)P]eIF-2alpha contained in fixed, dried, and stained gel slices was achieved with Staphylococcus aureus protease V8, chymotrypsin, or subtilisin, and the partial (32)P-labeled cleavage products were analyzed by gel electrophoresis. Each protease produced distinct and reproducible [(32)P]phosphopeptide profiles after partial or exhaustive proteolysis of [(32)P]eIF-2alpha. With a given protease, identical [(32)P]phosphopeptide patterns were obtained whether eIF-2alpha was phosphorylated by the heme-regulated or the double-stranded RNA-activated kinase. These data indicate that, in vitro, the kinases phosphorylate sites on eIF-2alpha that are identical or proximally located in the primary sequence. In this report we also provide preliminary evidence that the two eIF-2alpha kinases activated in lysates by heme deficiency or double-stranded RNA phosphorylate site(s) of endogenous eIF-2alpha that are similar, if not identical, to the sites phosphorylated in vitro with partially purified eIF-2alpha kinase(s) and eIF-2.


Assuntos
Fatores de Iniciação de Peptídeos/metabolismo , Proteínas Quinases/metabolismo , Proteínas/metabolismo , Reticulócitos/metabolismo , Animais , Fator de Iniciação 2 em Eucariotos , Heme/metabolismo , Substâncias Macromoleculares , Fosforilação , RNA de Cadeia Dupla/metabolismo , Coelhos , Especificidade por Substrato
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA