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1.
Arch Esp Urol ; 65(4): 502-4, 2012 May.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-22619144

RESUMO

OBJECTIVE: To describe one case of syringocele in an adult patient. METHODS/RESULTS: We report the case of a 26 year old man who presented frequency, hematuria and fever during one year, mictional cystourethrography showed a syringocele. Treatment consisted in endoscopic surgery, with good results in the follow-up. CONCLUSIONS: The syringocele is a relatively infrequent entity, that is necessary to study in a young patient with voiding symptoms, accompanied or not of haematuria and fever. The diagnosis is based on the cystourethrography, and treatment consisted, usually, in endoscopic surgery.


Assuntos
Hérnia/diagnóstico por imagem , Medula Espinal/diagnóstico por imagem , Doenças Uretrais/diagnóstico por imagem , Adulto , Humanos , Masculino , Radiografia
2.
Med Intensiva (Engl Ed) ; 44(9): 525-533, 2020 Dec.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-32654921

RESUMO

OBJECTIVE: To describe the clinical and respiratory characteristics of a cohort of 43 patients with COVID-19 after an evolutive period of 28 days. DESIGN: A prospective, single-center observational study was carried out. SETTING: Intensive care. PATIENTS: Patients admitted due to COVID-19 and respiratory failure. INTERVENTIONS: None. VARIABLES: Automatic recording was made of demographic variables, severity parameters, laboratory data, assisted ventilation (HFO: high-flow oxygen therapy and IMV: invasive mechanical ventilation), oxygenation (PaO2, PaO2/FiO2) and complications. The patients were divided into three groups: survivors (G1), deceased (G2) and patients remaining under admission (G3). The chi-squared test or Fisher exact test (categorical variables) was used, along with the Mann-Whitney U-test or Wilcoxon test for analyzing the differences between medians. Statistical significance was considered for p<0.05. RESULTS: A total of 43 patients were included (G1=28 [65.1%]; G2=10 [23.3%] and G3=5 [11.6%]), with a mean age of 65 years (range: 52-72), 62% males, APACHE II 18 (15-24), SOFA 6 (4-7). Arterial hypertension (30.2%) and obesity (25.6%) were the most frequent comorbidities. High-flow oxygen therapy was used in 62.7% of the patients, with failure in 85%. In turn, 95% of the patients required IMV and 85% received ventilation in prone decubitus. In the general population, initial PaO2/FiO2 improved after 7 days (165 [125-210] vs.194 [153-285]; p=0.02), in the same way as in G1 (164 [125-197] vs. 207 [160-294]; p=0.07), but not in G2 (163 [95-197] vs. 135 [85-177]). No bacterial coinfection was observed. The incidence of IMV-associated pneumonia was high (13 episodes/1000 days of IMV). CONCLUSIONS: Patients with COVID-19 require early IMV, a high frequency of ventilation in prone decubitus, and have a high incidence of failed HFO. The lack of improvement of PaO2/FiO2 at 7 days could be a prognostic marker. .


Assuntos
COVID-19/epidemiologia , Pandemias , SARS-CoV-2 , Distribuição por Idade , Idoso , Antibacterianos/uso terapêutico , Infecções Bacterianas/complicações , Infecções Bacterianas/tratamento farmacológico , COVID-19/mortalidade , COVID-19/terapia , Distribuição de Qui-Quadrado , Contraindicações de Procedimentos , Feminino , Mortalidade Hospitalar , Hospitalização/estatística & dados numéricos , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Multimorbidade , Ventilação não Invasiva/efeitos adversos , Estudos Prospectivos , Respiração Artificial/métodos , Espanha/epidemiologia , Estatísticas não Paramétricas , Centros de Atenção Terciária , Tratamento Farmacológico da COVID-19
3.
J Cell Biol ; 36(1): 33-44, 1968 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-5642685

RESUMO

The cytological changes observed in the A and D cells of rabbit endocrine pancreas incubated in a medium containing 0.6 mg/ml or 3 mg/ml of glucose are described. These cells showed no changes in their fine structure nor any signs of degranulation. When the A cells were incubated in a medium without glucose, they released A granules and synthesized new hormone. The way in which A granules are eliminated is compared to that following insulinic hypoglycemia in the animal in vivo. In both cases, the mechanism of secretion involves margination, emiocytosis of the entire granule, and formation of microvilli, in contrast to previously reported observations (9). The D cells showed no alteration of their fine structure after incubation with different concentrations of glucose in the medium. Only very rarely could we observe morphological changes which were suggestive of emiocytosis of the entire D granule.


Assuntos
Pâncreas/citologia , Pâncreas/metabolismo , Animais , Núcleo Celular , Meios de Cultura , Citoplasma , Grânulos Citoplasmáticos , Glucose/metabolismo , Complexo de Golgi , Técnicas In Vitro , Microscopia Eletrônica , Mitocôndrias , Coelhos
4.
J Clin Invest ; 88(6): 2123-30, 1991 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1661299

RESUMO

Genetic analysis in our laboratory of families with generalized thyroid hormone resistance (GTHR) has demonstrated tight linkage with a locus, c-erbA beta, encoding a nuclear T3 receptor. Three point mutations and two deletions in this locus have previously been reported in affected individuals in unrelated families as potential molecular bases for this disorder. In the present study, we have used direct sequencing of polymerase chain reaction-amplified exons of the c-erbA beta gene to rapidly identify novel point mutations from seven previously uncharacterized kindreds with GTHR. Six single base substitutions and one single base insertion were identified and found to be clustered in two regions of exons 9 and 10 in the ligand binding domain of the receptor: in the distal ligand-binding subdomain L2 and across the juncture of the taui and dimerization subdomains. Reduction of T3-binding affinity in each of four mutations tested as well as segregation of all mutations to clinically affected individuals strongly supports the hypothesis that these changes are the cause of GTHR in these kindreds. In view of the diversity of clinical phenotypes manifested, the distinct topographic clustering of the mutations provides an invaluable genetic tool for the molecular dissection of thyroid receptor function.


Assuntos
Mutação , Proteínas Proto-Oncogênicas/genética , Receptores dos Hormônios Tireóideos/genética , Hormônios Tireóideos/farmacologia , Tri-Iodotironina/metabolismo , Adolescente , Adulto , Sequência de Bases , Sítios de Ligação , Criança , Pré-Escolar , Resistência a Medicamentos , Éxons , Feminino , Humanos , Lactente , Masculino , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Receptores dos Hormônios Tireóideos/metabolismo , Glândula Tireoide/fisiopatologia
5.
An Otorrinolaringol Ibero Am ; 34(3): 231-6, 2007.
Artigo em Espanhol | MEDLINE | ID: mdl-17725166

RESUMO

Paranasal sinuses and nose metastasis are very uncommon. About 50 have been reported. Renal cell carcinoma is the primary neoplasm which most frequently metastasizes in the nasosinusal region, followed by breast and lug. Symptoms are unspecific, but the epistaxis constitutes the most common sign due to the significant vascularizations of the tumor. Prognosis is poor. The survival rate fluctuates between 15-30% at 5 years. Surgery is the elective treatment.


Assuntos
Carcinoma de Células Renais/secundário , Neoplasias Renais , Neoplasias do Seio Maxilar/secundário , Antineoplásicos/uso terapêutico , Biópsia , Carcinoma de Células Renais/diagnóstico por imagem , Carcinoma de Células Renais/tratamento farmacológico , Carcinoma de Células Renais/patologia , Carcinoma de Células Renais/radioterapia , Carcinoma de Células Renais/cirurgia , Terapia Combinada , Feminino , Humanos , Interferons/uso terapêutico , Neoplasias Renais/cirurgia , Seio Maxilar/patologia , Neoplasias do Seio Maxilar/diagnóstico por imagem , Neoplasias do Seio Maxilar/tratamento farmacológico , Neoplasias do Seio Maxilar/patologia , Neoplasias do Seio Maxilar/radioterapia , Pessoa de Meia-Idade , Nefrectomia , Prognóstico , Fatores de Tempo , Tomografia Computadorizada por Raios X
6.
Histol Histopathol ; 32(10): 1089-1097, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28127725

RESUMO

Testicular Leydig cells (LC) regulate the proper development of male individuals, both during fetal life (fetal LC) and puberty (adult LC). In the ovaries of adult women, there are cells that are very similar to Leydig cells, the ovarian hilus cells (OHC), which also produce testosterone. The origin of these cells, in both sexes, remains unknown and is still a matter of debate. We have studied the location, characteristics and relationships of the OHC in 90 patients. The indications for oophorectomy were: metrorrhagia (n=9), prolapse (n=8), endometrial hyperplasia (n=14), cancer (endometrial, myometrial, or cervical) (n=35), uterine leiomyomata (n=14), and various ovarian tumors (cysts and benign tumors, borderline and malignant) (n=10). In addition to the hilus, occasionally the nodules, nests and clusters of OHC were located in the mesovarium, the mesosalpinx, and in the medullar and cortical regions of the ovaries. The morphological (including crystalloids of Reinke) and immunohistochemical (positivity for calretinin and alpha-inhibin) findings were similar to those described for testicular LC. Therefore, OHC can be considered ovarian Leydig cells (OLC). LC are usually found in small numbers in the ovaries, but if one looks for them intentionally, one always finds them. Close relationships were observed between the OLC with nerves and vessels. Moreover, an intraneural location of the OLC was demonstrated in all cases, and these intraneural cells showed similar characteristics to extraneural OLC, suggesting that they derive from endoneural cells which are present in the vegetative nerves of the ovaries.


Assuntos
Células Intersticiais do Testículo/patologia , Ovário/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imuno-Histoquímica , Células Intersticiais do Testículo/metabolismo , Masculino , Pessoa de Meia-Idade , Neurônios/metabolismo , Neurônios/patologia , Doenças Ovarianas/patologia , Doenças Ovarianas/cirurgia , Ovariectomia , Ovário/inervação , Ovário/metabolismo
7.
Actas Urol Esp ; 30(9): 954-7, 2006 Oct.
Artigo em Espanhol | MEDLINE | ID: mdl-17175938

RESUMO

Paranasal sinuses and nose metastasis are very uncommon tumors, about 50 have been reported. Renal cell carcinoma is the primary neoplasm which most frequently metastasizes in the nasosinusal region, followed by breast and lung. Symptoms are unspecific, but the epistaxis constitutes the most common sign due to the significant vascularizations of the tumor. Prognosis is poor. The survival rate fluctuates between 15-30% at 5 years. Surgery is the elective treatment.


Assuntos
Carcinoma de Células Renais/secundário , Neoplasias Renais/patologia , Neoplasias do Seio Maxilar/diagnóstico por imagem , Neoplasias do Seio Maxilar/secundário , Carcinoma de Células Renais/diagnóstico por imagem , Feminino , Humanos , Pessoa de Meia-Idade , Radiografia
8.
Biochim Biophys Acta ; 972(2): 192-9, 1988 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-3191164

RESUMO

Phenylephrine increases hepatic gluconeogenesis for as long as it is present in the extracellular medium. This effect is accompanied by a parallel increase in oxygen consumption. No apparent stoichiometric relationship exists between the phenylephrine-stimulated respiration and the energy required to meet the demands of gluconeogenesis. In the absence of extracellular calcium, no sustained stimulation of respiration was observed and phenylephrine failed to enhance gluconeogenesis; however, acute and transient effects of the alpha-adrenergic agonist were still observable. The following observations indicate that fatty acids are not involved in the alpha-adrenergic response: (1) the effects of phenylephrine and octanoate on respiration and gluconeogenesis were found to be additive; (2) unlike phenylephrine, octanoate is capable of stimulating gluconeogenesis in calcium-depleted liver; (3) in the absence of calcium, phenylephrine was incapable of further stimulating respiration or gluconeogenesis in the presence of octanoate. It is concluded that the conditions of increased lipid mobilization and/or oxidation are not sufficient to explain the metabolic response to alpha-adrenergic agonists. Fatty acids and alpha-adrenergic stimulation share a common role of stimulating gluconeogenesis in a manner dependent on their ability to stimulate respiration; however, the additive nature of their effects and distinct calcium requirements indicate that they act to trigger different mechanisms.


Assuntos
Caprilatos/farmacologia , Gluconeogênese/efeitos dos fármacos , Fígado/metabolismo , Fenilefrina/farmacologia , Animais , Cinética , Lactatos/metabolismo , Ácido Láctico , Fígado/efeitos dos fármacos , Masculino , Consumo de Oxigênio/efeitos dos fármacos , Perfusão , Piruvatos/metabolismo , Piruvatos/farmacologia , Ácido Pirúvico , Ratos , Ratos Endogâmicos , Valores de Referência
9.
Biochim Biophys Acta ; 1051(3): 215-20, 1990 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-2310772

RESUMO

Calcium depletion induced by perfusing livers with calcium-free buffer did not alter the rates of basal glucose production from pyruvate or from increasing concentrations of lactate. However, calcium deficiency selectively prevented the fatty acid-induced stimulation of gluconeogenesis from lactate. This effect is not related to the higher NAD redox potential consistently observed in Ca2(+)-deficient livers. On the other hand, octanoate was capable of inducing dose-dependent changes in the [pyruvate]0.5 in calcium-depleted livers perfused with lactate, ruling out that low cellular calcium content could perturb the mitochondrial transport of pyruvate. The observation that the effect of calcium deficiency can be overcome by supraphysiological concentrations of pyruvate supports the proposal that stimulation of the maximal capacity of the gluconeogenic pathway by fatty acid relies largely on the tricarboxylic acid cycle activity, restricted in calcium deficiency conditions.


Assuntos
Cálcio/metabolismo , Caprilatos/metabolismo , Gluconeogênese , Lactatos/metabolismo , Fígado/metabolismo , Piruvatos/metabolismo , Animais , Soluções Tampão , Cálcio/farmacologia , Caprilatos/farmacologia , Relação Dose-Resposta a Droga , Gluconeogênese/efeitos dos fármacos , Lactatos/farmacologia , Masculino , Perfusão , Piruvatos/farmacologia , Ratos , Ratos Endogâmicos
10.
Biochim Biophys Acta ; 883(1): 33-40, 1986 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-3015233

RESUMO

Acute administration of glucagon to the rat in vivo inhibits hepatic polypeptide chain elongation by about 30%. This effect was not observed in adrenalectomized rats, despite the significant increases in the hepatic content of cyclic AMP. Fatty acid administration mimics the glucagon action on protein synthesis; however, in adrenalectomized animals they were ineffective. Whether glucagon or fatty acids were administered, there was a significant increase in the state of reduction of the NAD system in normal as well as in adrenalectomized rats. This observation rules out the change in the cellular state of reduction as the mediator of their action on protein synthesis. A correlation was observed between the ability of glucagon or fatty acids to inhibit protein synthesis and to stimulate gluconeogenesis. An increased biosynthetic activity as reflected by an increased gluconeogenic flux is accompanied by a decreased phosphorylation state of adenine nucleotides that might be responsible for the inhibitory effect on protein synthesis. In adrenalectomized animals in which neither glucagon nor fatty acids stimulate gluconeogenesis, no effects on phosphorylation state or on the rate of protein synthesis were detected.


Assuntos
Gluconeogênese , Fígado/metabolismo , Biossíntese de Proteínas , Nucleotídeos de Adenina/metabolismo , Adrenalectomia , Animais , Caprilatos/farmacologia , AMP Cíclico/farmacologia , Ácidos Graxos/farmacologia , Glucagon/farmacologia , Gluconeogênese/efeitos dos fármacos , Cinética , Fígado/efeitos dos fármacos , Masculino , NAD/metabolismo , Oxirredução , Fosforilação , Prednisolona/farmacologia , Ratos , Ratos Endogâmicos
11.
Biochim Biophys Acta ; 1262(1): 91-4, 1995 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-7772607

RESUMO

This work reports the primary nucleotide structure and in vitro translation of a cDNA, expressed by a gene mapping on chromosome 12, that encodes a human hepatic alpha-glycerol-3-phosphate dehydrogenase (L-glycerol-3-phosphate:NAD oxidoreductase, E.C. 1.1.1.8). The 1413 bp cDNA comprises an ORF of 1050 bp that encodes a 349 amino acid protein of 37.5 kDa. Northern blot analysis of poly(A)+ mRNA from human liver showed three transcripts, while from human placenta only two transcripts were detected.


Assuntos
Glicerolfosfato Desidrogenase/genética , Fígado/enzimologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , DNA Complementar , Glicerol-3-Fosfato Desidrogenase (NAD+) , Glicerolfosfato Desidrogenase/química , Glicerolfosfato Desidrogenase/metabolismo , Humanos , Cinética , Dados de Sequência Molecular
12.
Biochim Biophys Acta ; 721(2): 208-17, 1982 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-6291628

RESUMO

(1) Glucose stimulates the incorporation of amino acids into protein in lung cells isolated by digestion of the lung stroma with collagenase. This effect reflects mainly an increase in protein synthesis since no effect of glucose had been found to the uptake of amino acid precursors and, although glucose decreases the rate of intracellular proteolysis by 15%, this effect cannot account for the increased incorporation of radioactivity into proteins. Furthermore, glucose did not induce any significant change in the intracellular content of valine. (2) For glucose to act on protein synthesis, it must be glycolyzed since its stereoisomer, L-glucose, which is not metabolized by lung cells, has no effect. (3) The mechanism of glucose action does not seem to be related simply to variations of cellular ATP content or energy charge. The following arguments seem to support this conclusion: (i) glucose does not bring about significant variations in the concentration of reactants of the adenylate system; (ii) the increase in protein synthesis induced by glucose in energy-depleted cells correlates with a rise in ATP content and energy charge; however, adenosine, which increases ATP levels in a form quantitatively similar to glucose, is unable to affect protein synthesis: (iii) glucose also accelerates the incorporation of amino acids into proteins in adenosine-treated lung cells in which the ATP concentration was almost double that of the control and the energy charge was considerably elevated, ruling out the possibility that a rise in the steady-state concentration of ATP and/or energy charge alone could be responsible for the acceleration of protein synthesis. (4) It can be concluded that the effect of glucose in increasing protein synthesis in lung cells is dependent on some signal arising from its breakdown and not to variations in the concentration of reactants or energy charge of the adenylate system.


Assuntos
Nucleotídeos de Adenina/metabolismo , Glicólise , Pulmão/metabolismo , Biossíntese de Proteínas , Valina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Glucose/farmacologia , Técnicas In Vitro , Iodoacetatos/farmacologia , Ácido Iodoacético , Cinética , Pulmão/efeitos dos fármacos , Masculino , Manose/farmacologia , Colagenase Microbiana , Ratos , Ratos Endogâmicos
13.
Biochim Biophys Acta ; 760(1): 175-84, 1983 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-6615881

RESUMO

(1) The addition of long chain fatty acids to the incubation medium of isolated rat lung cells produced a dose-dependent inhibition of protein labelling from L-[3H]valine. Maximal rate changes were observed at fatty acids levels within the range of their physiological concentration. (2) The effect of fatty acids on protein labelling does not seem to be mediated by their oxidation. The following observations seem to support this conclusion: (a) the rate of fatty acid oxidation by lung cells was remarkably low, so that no significant variations in the state of reduction of the NAD system were detected; (b) there was no correspondence in the dose-response patterns of fatty acid oxidation and inhibition of protein labelling; (c) octanoate was much more actively oxidized than oleate, however the latter was more effective in decreasing protein labelling. (3) An apparent relationship between the length of the fatty chain and its ability to inhibit protein labelling seems to exist. The longer the chain the stronger the inhibitory effect observed. (4) The effect of fatty acid on protein labelling seems to be mediated by a cellular energy depletion secondary to an inhibition of the respiratory chain. Their ability to decrease oxygen uptake and adenine nucleotide content was also proportional to the chain length. (5) Glucose, which apparently acted by increasing energy production at substrate level phosphorylation, partially prevented the inhibitory effect of fatty acid on protein labelling. This observation supports the point of view that fatty acids do not act in decreasing protein labelling by perturbing directly the protein synthesis machinery but decreasing the phosphorylation potential.


Assuntos
Ácidos Graxos não Esterificados/metabolismo , Glucose/farmacologia , Pulmão/metabolismo , Biossíntese de Proteínas/efeitos dos fármacos , Nucleotídeos de Adenina/metabolismo , Animais , Radioisótopos de Carbono , Metabolismo Energético/efeitos dos fármacos , Ácidos Graxos não Esterificados/farmacologia , Técnicas In Vitro , Cinética , Pulmão/efeitos dos fármacos , Masculino , Proteínas/genética , Ratos
14.
Biochim Biophys Acta ; 1220(1): 49-56, 1993 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-8268244

RESUMO

The present work aimed to further characterise the hepatic alpha 1-adrenergic actions by studying the influence of nutritional status and/or extracellular medium composition in the alpha 1-adrenoceptor-induced responses. The experiments were performed in a non-recirculating liver-perfusion system featuring continuous monitoring of vascular resistance, as well as the effluent perfusate changes in pO2, pCa2+, pK+ and pH. The alpha 1-adrenoceptor activation produced biphasic responses to most parameters studied. The acute phase lasted for about 3 min and it was followed by a phase of sustained stimulation that lasted as long as the receptor activation was maintained. Our data indicate that there is not a single pattern of alpha 1-adrenergic responses but variable patterns depending on the nutritional status and the experimental conditions. Gluconeogenic substrates alone produced reciprocal changes in the outflow perfusate pH and Ca2+ activity. The magnitude of these changes indicates that the diversity of alpha 1-adrenoceptor responses are the result of the superposed effects of different rates of substrates and/or metabolites transport. The sustained alpha 1-adrenoceptor stimulation produced extracellular acidification and increases in respiration, vascular resistance and Ca2+ release. These responses required physiological extracellular [Ca2+]. At low extracellular [Ca2+], the alpha 1-adrenoceptor activation failed to acidify the extracellular medium, suggesting that receptor-induced H+ efflux demands normal rates of Ca2+ influx. The correlation between alpha 1-adrenergic-induced increase in O2 uptake and Ca2+ release indicates that the increased energy production can be accounted for by the energy cost of Ca2+ release. The alpha 1-agonist concentration-response studies have shown significant differences in the [alpha 1-agonist]0.5 for each type of response, suggesting the existence of multiple alpha 1-adrenoceptor-coupled signal-transduction pathways.


Assuntos
Fígado/metabolismo , Receptores Adrenérgicos alfa/metabolismo , Animais , Gluconeogênese , Fígado/efeitos dos fármacos , Masculino , Estado Nutricional , Perfusão , Fenilefrina/farmacologia , Ratos , Ratos Wistar
15.
Biochim Biophys Acta ; 1158(2): 166-74, 1993 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-8399317

RESUMO

Stimulation of ureogenesis by ornithine and/or NH4Cl inhibited gluconeogenesis from lactate but not from equimolar concentrations of pyruvate in perfused rat liver. Neither a shortage of energy nor a decrease in alpha-ketoglutarate availability seems to be responsible for this inhibition. With lactate as substrate the extracellular concentration of pyruvate attained was approximately equal to 0.15 mM that assuming reflects its cytosolic concentration it would be limiting for its mitochondrial transport. Stimulation of ureogenesis from NH4Cl enhances flux through pyruvate dehydrogenase. Furthermore, activation of pyruvate dehydrogenase by dichloroacetate led to stimulation of ureogenesis and inhibition of glucose production. Conversely, inhibition of pyruvate dehydrogenase flux by fatty acid enhanced glucose production and inhibited ureogenesis. Thus, ornithine and/or NH4Cl seem to inhibit lactate to glucose flux by shifting the mitochondrial partitioning of pyruvate from carboxylation towards decarboxylation with the result of a decreased oxaloacetate formation. Gluconeogenic substrates enhanced the hepatic uptake of ornithine. However, no correlation seems to exist between the uptake of ornithine, ornithine-induced stimulation of ureogenesis and total rates of urea production. Ornithine produced a concentration-dependent acidification of the hepatic outflow perfusate, suggesting that it may be transported in exchange for H+.


Assuntos
Gluconeogênese , Fígado/metabolismo , Ureia/metabolismo , Cloreto de Amônio/farmacologia , Animais , Ácido Dicloroacético/farmacologia , Gluconeogênese/efeitos dos fármacos , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Lactatos/metabolismo , Ácido Láctico , Masculino , Ácido Oleico , Ácidos Oleicos/farmacologia , Ornitina/farmacologia , Perfusão , Piruvatos/metabolismo , Ácido Pirúvico , Ratos , Ratos Wistar , Fatores de Tempo
16.
Endocrinology ; 136(2): 468-75, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7835278

RESUMO

The present work aimed to study the influence of corticosteroids on the alpha 1-adrenoreceptor-induced activation of hepatic metabolic functions. The experiments were performed in a nonrecirculating liver perfusion system featuring continuous monitoring of pO2, pCa2+, Ca2+, pH, and portal pressure. The alpha 1-adrenergic-induced stimulation of respiration, H+ and Ca2+ release, glycogen breakdown, and gluconeogenesis, were diminished in livers from adrenalectomized animals. The normal liver responsiveness was restored on administration of exogenous corticosteroids but not mineralocorticoids. The following observations support the conclusion that corticosteroids control a hepatocyte-specific early postreceptor step in the alpha 1-adrenergic signaling pathway: 1) the alpha 1-adrenergic stimulation of vascular smooth muscle contraction was not impaired by corticosteroid deficiency; 2) the alpha 1-adrenoreceptor ligand-binding affinity does not seem to be altered by adrenalectomy; 3) the alpha 1-adrenergic-induced intracellular alkalosis, protein kinase C activation, and Ca2+ mobilization were diminished in hepatocytes from adrenalectomized rats, indicating that both Ca(2+)-dependent and -independent processes were altered; and 4) non-receptor-mediated homeostatic mechanisms of metabolic or intracellular pH control were not impaired by adrenalectomy.


Assuntos
Corticosteroides/farmacologia , Fígado/metabolismo , Proteína Quinase C/metabolismo , Receptores Adrenérgicos alfa 1/metabolismo , Corticosteroides/antagonistas & inibidores , Adrenalectomia , Animais , Cálcio/metabolismo , Membrana Celular/metabolismo , Células Cultivadas , Ativação Enzimática/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Testes de Função Hepática , Masculino , Contração Muscular/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , Ensaio Radioligante , Ratos , Ratos Wistar , Vasopressinas/farmacologia
17.
Endocrinology ; 133(5): 2105-15, 1993 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8404660

RESUMO

The present work aimed to determine the role played by protein kinase-C (PKC) in the alpha 1-adrenoceptor-induced activation of hepatic metabolism. The following observations indicate that activation of PKC is a condition necessary for alpha 1-adrenoceptor activation of hepatic functions, but not sufficient to mimic the receptor-mediated effects in the absence of external physiological stimuli. 1) alpha 1-Adrenoceptor activation promoted the translocation of PKC from the cytosol to its active form in the plasma membrane. 2) Activation of PKC by the phorbol ester 12-myristate 13-acetate or exogenous diacylglycerols or by elevation of endogenous levels of diacylglycerols by inhibiting diacylglycerol kinase mimicked the alpha 1-adrenoceptor-mediated actions. However, the time course and magnitude of the nonreceptor responses differ from those mediated by alpha 1-adrenoceptor activation. In addition, nonreceptor-mediated activation of PKC decreased the alpha 1-adrenoceptor responsiveness. 3) Inhibition of PKC by either H-7 [1-(5-isoquinolinilsulfonyl)2-methylpiperazine] or staurosporine inhibited all of the alpha 1-adrenoceptor-induced responses, except gluconeogenesis. The vasopressin effects were not inhibited by H-7, indicating that PKC activation is a distinct feature of the hepatic alpha 1-adrenoceptor activation that is not shared by all the Ca(2+)-mobilizing agonists. The diacylglycerol-PKC branch of the alpha 1-adrenoceptor signaling pathway seems to control the sustained phase of stimulation of hepatic functions. In these studies we have also observed that phorbol 12-myristate 13-acetate produces a concentration-dependent inhibition of hepatic respiration. However, decreased energy availability does not seem to be the cause of its action to decrease alpha 1-adrenoceptor responsiveness.


Assuntos
Fígado/fisiologia , Proteína Quinase C/metabolismo , Receptores Adrenérgicos alfa/fisiologia , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina , Alcaloides/farmacologia , Animais , Transporte Biológico , Membrana Celular/enzimologia , Citosol/enzimologia , Diglicerídeos/farmacologia , Ativação Enzimática/efeitos dos fármacos , Isoquinolinas/farmacologia , Cinética , Masculino , Perfusão , Piperazinas/farmacologia , Proteína Quinase C/antagonistas & inibidores , Ratos , Ratos Wistar , Estaurosporina , Acetato de Tetradecanoilforbol/farmacologia
18.
J Clin Endocrinol Metab ; 75(4): 1039-45, 1992 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1400869

RESUMO

Generalized resistance to thyroid hormone is an inherited disease characterized by unresponsiveness of pituitary and peripheral tissues to thyroid hormone. Genetic analysis of several kindreds linked this syndrome to the gene for the beta-form of the thyroid hormone receptor, and this led to the subsequent identification of various mutations in the ligand-binding domain of this receptor. In this region we now have found 4 new point mutations with reduced T3-binding affinities from separate kindreds by direct sequencing of polymerase chain reaction products. Similar to previously studied kindreds, the reduction in T3 binding of these four kindreds ranged from 2.5- to 5-fold, indicating that these are not neutral polymorphisms. Furthermore, the pattern of inheritance of these 4 kindreds is familial in 2, sporadic in 1, and unknown in 1. To date, 20 distinct mutations have been identified, of which 18 are clustered in 2 distinct topographical regions: 11 are within the tau i/dimerization subdomains of exon 9, and 7 are within the L2 subdomain of exon 10. The 4 newly identified mutations coupled to the 9 mutations our laboratory has previously identified provide new insights into the clinical aspects of generalized resistance to thyroid hormone. Kindreds with mutations in exon 9 compared with those in exon 10 have significantly more problems in language development, as manifested by articulation problems and/or wide discrepancies in verbal and performance IQs. Interestingly, marked variability in language deficiency as well as other clinical patterns were seen not only between kindreds but also within a kindred. Further identification and clinical correlations of new mutations will continue to enhance our understanding of the structure/function relationships and physiological role of the human thyroid hormone receptor.


Assuntos
Transtornos da Linguagem/genética , Mutação/genética , Receptores dos Hormônios Tireóideos/genética , Adolescente , Adulto , Idoso , Sequência de Bases , Criança , Pré-Escolar , Éxons/genética , Feminino , Humanos , Transtornos da Linguagem/metabolismo , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Testes Neuropsicológicos , Fenótipo , Reação em Cadeia da Polimerase , Testes de Função Tireóidea
19.
Gene ; 226(1): 111-9, 1999 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-9889342

RESUMO

The human malic enzyme (hME) promoter contains an inverted palindromic (IP4) 3,5,3'-triiodo-thyronine (T3) response element (T3RE) 15bp downstream from an activating protein-1 (AP-1) site. The purpose of this study was to analyze the functional relationship between both cis-acting elements. The following observations indicate that these two elements operate as a functional unit in controlling the human ME gene:T3 failed to stimulate transcription above the basal levels in cells overexpressing either TRb or TRb/retinoid acid receptor (RXR), indicating that TRbeta acts primarily as a transcriptional repressor in the context of the hME. Moreover, the finding of a repressive effect of TRbeta without DNA binding suggests the existence of both DNA-dependent and independent mechanisms of TRbeta-induced repression of transcription.


Assuntos
Malato Desidrogenase/genética , Receptores dos Hormônios Tireóideos/metabolismo , Sequências Reguladoras de Ácido Nucleico , Elementos de Resposta/fisiologia , Fator de Transcrição AP-1/metabolismo , DNA/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica , Humanos , Malato Desidrogenase/metabolismo , Mutação , Regiões Promotoras Genéticas , Receptores do Ácido Retinoico/genética , Receptores do Ácido Retinoico/metabolismo , Receptores dos Hormônios Tireóideos/efeitos dos fármacos , Receptores dos Hormônios Tireóideos/genética , Receptores X de Retinoides , Fator de Transcrição AP-1/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica , Tri-Iodotironina/metabolismo , Tri-Iodotironina/farmacologia
20.
Gene ; 159(2): 255-60, 1995 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-7622060

RESUMO

This work reports the structure of a cDNA (ME) encoding a human malic enzyme (ME) (malate NADP oxidoreductase, EC 1.1.1.40) elucidated by joining several overlapping fragments amplified by PCR from human hepatic cDNA or from cDNA libraries. The full-length cDNA has an open reading frame (ORF) of 1719 bp that encodes a 572-amino-acid protein of 64 113 Da, similar to the native monomeric, cytosolic, NADP-dependent ME isolated from human liver. The comparison of the structure of this cDNA with that of the human mitochondrial NAD(P)-dependent ME (EC 1.1.1.39) shows a homology of 63%, suggesting that these two forms originated from the same gene. The expression of the cDNA in Escherichia coli as a translational fusion (glutathione S-transferase::ME) protein yielded a product of the predicted mass. The recombinant protein shows NADP-dependent malate oxidoreductase activity and is virtually inactive with NAD. It also shows other distinct features of the native cytosolic NADP-dependent ME, like Mn2+ dependence, similar substrate (Km = 117 microM) and cofactor affinity (Km = 2 microM) constants, and a lack of allosteric regulation. In human proliferative cells, the NADP-dependent ME activity is poorly expressed and barely inducible by thyroid hormones.


Assuntos
Fígado/enzimologia , Malato Desidrogenase/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , DNA Complementar/genética , Escherichia coli/genética , Regulação Enzimológica da Expressão Gênica , Humanos , Malato Desidrogenase/biossíntese , Dados de Sequência Molecular , RNA Mensageiro/análise , Proteínas Recombinantes de Fusão/biossíntese , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Distribuição Tecidual
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