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1.
Lett Appl Microbiol ; 67(5): 442-448, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30152866

RESUMO

The objectives of this study were to assess the effectiveness of an ultraviolet (UV-C, 254 nm) irradiation system and the spray-drying method as two independent safety steps on inactivation of Escherichia coli K88 and K99 spiked in porcine plasma at 6·46 ± 0·04 log10  ml-1 and 6·78 ± 0·67 log10  ml-1 respectively for UV-C method, and at 7·31 ± 0·39 log10  ml-1 and 7·66 ± 0·11 log10  ml-1 , respectively for the spray-drying method. The UV-C method was performed at different UV light doses (from 750 to 9000 J l-1 ) using a pilot plant UV-C device working under turbulent flow. Spray-drying treatment was done at inlet temperature 220 ± 1°C and two different outlet temperatures, 80 ± 1°C or 70 ± 1°C. Results indicated that UV-C treatment induced a 4 log10 viability reduction for both E. coli at 3000 J l-1 . Full inactivation of both E. coli strains was achieved in all spray-dried samples dehydrated at both outlet temperatures. The special UV-C system design for turbid liquid porcine plasma is a novel treatment that can provide an additional redundant biosafety feature that can be incorporated into the manufacturing process for spray-dried animal plasma. SIGNIFICANCE AND IMPACT OF THE STUDY: The safety of raw materials from animal origin such as spray-dried porcine plasma (SDPP) may be a concern for the swine industry. Ultraviolet treatment at 254 nm (UV-C) of liquid plasma has been proposed as an additional biosafety feature in the manufacturing process of SDPP. We found that UV-C exposure in the liquid plasma at 3000 J l-1 reduces about 4 log10 ml-1 for E. coli K88 and K99. Full inactivation of both E. coli strains was achieved in all spray-dried samples. The incorporation of UV-C treatment to liquid plasma improves the robustness of the SDPP manufacturing process.


Assuntos
Ração Animal/microbiologia , Escherichia coli Enterotoxigênica/crescimento & desenvolvimento , Raios Ultravioleta , Animais , Dessecação , Plasma/microbiologia , Suínos/sangue , Doenças dos Suínos/microbiologia , Doenças dos Suínos/prevenção & controle
2.
Lett Appl Microbiol ; 67(2): 205-211, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29889981

RESUMO

The objective of this study was to determine the effectiveness of the spray-drying process on the inactivation of Salmonella choleraesuis and Salmonella typhimurium spiked in liquid porcine plasma and to test the additive effect of immediate postdrying storage. Commercial spray-dried porcine plasma was sterilized by irradiation and then reconstituted (1:9) with sterile water. Aliquots of reconstituted plasma were inoculated with either S. choleraesuis or S. typhimurium, subjected to spray-drying at an inlet temperature of 200°C and an outlet temperature of either 71 or 80°C, and each spray-drying temperature combinations were subjected to either 0, 30 or 60 s of residence time (RT) as a simulation of residence time typical of commercial dryers. Spray-dried samples were stored at either 4·0 ± 3·0°C or 23·0 ± 0·3°C for 15 days. Bacterial counts of each Salmonella spp., were completed for all samples. For both Salmonella spp., spray-drying at both outlet temperatures reduced bacterial counts about 3 logs at RT 0 s, while there was about a 5·5 log reduction at RT 60 s. Storage of all dried samples at either 4·0 ± 3·0°C or 23·0 ± 0·3°C for 15 days eliminate all detectable bacterial counts of both Salmonella spp. SIGNIFICANCE AND IMPACT OF THE STUDY: Safety of raw materials from animal origin like spray-dried porcine plasma (SDPP) may be a concern for the swine industry. Spray-drying process and postdrying storage are good inactivation steps to reduce the bacterial load of Salmonella choleraesuis and Salmonella typhimurium. For both Salmonella spp., spray-drying at 71°C or 80°C outlet temperatures reduced bacterial counts about 3 log at residence time (RT) 0 s, while there was about a 5.5 log reduction at RT 60 s. Storage of all dried samples at either 4.0 ± 3.0°C or 23.0 ± 0.3°C for 15 days was effective for eliminating detectable bacterial counts of both Salmonella spp.


Assuntos
Dessecação , Plasma/microbiologia , Salmonella typhimurium/crescimento & desenvolvimento , Doenças dos Suínos/microbiologia , Animais , Contagem de Colônia Microbiana , Temperatura Alta , Suínos
6.
Am J Physiol Endocrinol Metab ; 298(3): E634-43, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20040695

RESUMO

Glucagon-like peptide 1 (GLP-1) functions as an incretin hormone with antidiabetogenic properties. However, the role of GLP-1 in human bone marrow-derived mesenchymal stem cells (hMSCs), if any, remains unknown. The effects of GLP-1 on hMSCs were tested with regard to cell proliferation, cytoprotection, and cell differentiation into adipocytes. The signaling pathways involved in these processes were also analyzed. Cells were characterized with biochemical and morphological approaches before and after being induced to differentiate into adipocytes. PCNA protein levels were used as a proliferation index, whereas cell apoptosis was studied by deprivation of fetal bovine serum. Isolated hMSCs expressed stem cell markers as well as mRNA and GLP-1 receptor protein. GLP-1 increased the proliferation of hMSCs, which decreased when they were induced to differentiate into adipocytes. This process produced biochemical and morphological changes in cells expressing PPARgamma, C/EBPbeta, AP2, and LPL in a time-dependent pattern. Notably, GLP-1 significantly reduced the expression of PPARgamma, C/EBPbeta, and LPL. These effects were exerted at least through the MEK and PKC signaling pathways. In addition, GLP-1 significantly reduced cell apoptosis. Our data indicate that, in hMSCs, GLP-1 promotes cellular proliferation and cytoprotection and prevents cell differentiation into adipocytes. These latter findings underscore the potential therapeutic role of GLP-1 in preventing the adipocyte hyperplasia associated with obesity and, additionally, could bolster the maintenance of hMSC stores by promoting the proliferation and cytoprotection of undifferentiated hMSC.


Assuntos
Adipócitos/citologia , Adipócitos/metabolismo , Células da Medula Óssea/citologia , Células da Medula Óssea/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/fisiologia , Adulto , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Peptídeo 1 Semelhante ao Glucagon/administração & dosagem , Humanos , Incretinas/administração & dosagem , Incretinas/metabolismo , Masculino , Pessoa de Meia-Idade
8.
Vet Microbiol ; 239: 108450, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31753544

RESUMO

Liquid porcine plasma is an animal origin raw material for the manufacturing process of spray-dried porcine plasma that is used in pig nutrition worldwide. In previous studies we found that the application of ultraviolet light C (UV-C) in liquid plasma that was inoculated with a variety of bacteria or viruses of importance in the swine industry can be considered as redundant safety steps because in general achieve around 4 logs reduction for most of these pathogens. However, the final validation of the UV-C light as safety feature should be conducted with commercial liquid plasma and using the pig bioassay model. As a first objective, the potential infectivity of a raw liquid plasma product collected from an abattoir was tested by means of a swine bioassay. We used Porcine circovirus 2 (PCV-2), a ubiquitous virus that has been systematically detected by PCR in porcine plasma at abattoirs as selection criteria for commercial liquid plasma lot. As a second aim of the study, the effects of different doses of UV-C irradiation on the selected raw liquid plasma were assayed in the animal bioassay. Moreover, other swine infecting agents, including Porcine reproductive and respiratory syndrome virus (PRRSV), were also determined in the original plasma and monitored in the inoculated animals. Pigs negative for PCV-2 and PRRSV genome and antibodies were allotted to one of five groups (6 to 8 pigs/ group) and injected intra-peritoneally with 10 mL of their assigned inoculum at 50 d of age. Negative control pigs (group 1) were injected with PBS. Positive control pigs (group 5) were injected with a PCV-2 inoculum. Groups 2, 3 and 4 were injected with liquid porcine plasma that had been subjected to 0 (raw plasma), 3000 or 9000 J/L UV-C irradiation, respectively. Group 2 pigs (0 J/L UV-C) got infection by PRRSV but no PCV-2 infection or seroconversion. However, one pig from group 2 seroconverted to Rotavirus A (RVA) and Hepatitis E virus (HEV) and three group 2 pigs seroconverted to Porcine parvovirus (PPV). Groups 1, 3 and 4 pigs showed no evidence of infection or seroconversion associated with the tested viruses or any other pathogens found in the liquid plasma before UV-C irradiation. Group 5 pigs developed PCV-2 infectivity as expected. UV-C irradiation of liquid plasma at 3000 and 9000 J/L was effective in preventing PRRSV and other pathogens transmission. Moreover, raw liquid plasma was non-infectious for PCV-2 in naïve pigs.


Assuntos
Bioensaio , Circovirus/efeitos da radiação , Plasma/virologia , Vírus da Síndrome Respiratória e Reprodutiva Suína/efeitos da radiação , Raios Ultravioleta , Inativação de Vírus/efeitos da radiação , Animais , Circovirus/genética , Vírus da Síndrome Respiratória e Reprodutiva Suína/genética , Suínos
9.
Sci Total Environ ; 399(1-3): 193-201, 2008 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-18455757

RESUMO

The Iberian lynx (Lynx pardinus) is the most endangered felid in the world with a wild population which probably stands at less than 200 individuals inhabiting two areas in Southern Spain (Doñana and Sierra Morena) that are known to have been contaminated by heavy metals and metalloids due to a long history of mining activities. This contamination may pose a threat to long term conservation efforts and hence, the concentrations of seven elements (As, Se, Cd, Zn, Cu, Pb, Hg) were determined in the liver, muscle and bone of 9 lynx, as well as 17 red foxes (Vulpes vulpes), 11 Egyptian mongooses (Herpestes ichneumon), 4 common genets (Genetta genetta) and 1 Eurasian badger (Meles meles). The mean concentrations found were below the threshold levels indicative of chronic intoxication in all the species studied. In general, genet and red fox were species with the highest concentrations of several elements in Doñana, whilst Iberian lynx had the lowest levels of most of them. Lynx from Sierra Morena had significantly higher concentrations of bone Pb (2.05 microg/g d.w.) than those from Doñana (0.13 microg/g d.w.), probably due to the mineralised underlying geology and/or the abandoned mine workings in Sierra Morena. Egyptian mongoose presented liver concentrations of Hg up to 9.7 microg/g d.w. A strong relationship between Hg and Se levels was found in liver and muscle samples of all the studied species, especially in mongoose. In conclusion, levels of the studied elements do not appear to represent a significant threat for the lynx or for the other carnivores studied. However, given the critical status of the Iberian lynx, a continuous monitoring scheme remains necessary.


Assuntos
Animais Selvagens , Fígado/efeitos dos fármacos , Metais Pesados/toxicidade , Mineração , Músculo Esquelético/efeitos dos fármacos , Poluentes do Solo/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Carnívoros , Feminino , Raposas , Fígado/metabolismo , Lynx , Masculino , Metais Pesados/análise , Metais Pesados/metabolismo , Músculo Esquelético/metabolismo , Poluentes do Solo/análise , Poluentes do Solo/química , Poluentes do Solo/metabolismo , Espanha , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo
10.
Arch Soc Esp Oftalmol ; 83(7): 429-31, 2008 Jul.
Artigo em Espanhol | MEDLINE | ID: mdl-18592443

RESUMO

CASE REPORT: We present the case of a 34-year-old man with Sturge-Weber syndrome, who presented to the emergency room with left ocular pain and left chronic exophthalmos. He suffered an acute glaucoma secondary to pupillary block consequent upon an anterior lens subluxation. Orbital contrast Magnetic Resonance Imaging (MRI) was performed and he underwent intracapsular lens extraction. DISCUSSION: The MRI showed T2 enhanced lesions in the left meninges, choroid, and orbit, compatible with cavernous hemangiomas, as well as a dilated superior ophthalmic vein. Intraocular pressure after cataract surgery was 10 mm Hg, and visual acuity was less than 20/200.


Assuntos
Neoplasias da Coroide/etiologia , Glaucoma de Ângulo Fechado/etiologia , Subluxação do Cristalino/etiologia , Neoplasias Orbitárias/etiologia , Síndrome de Sturge-Weber/complicações , Adulto , Extração de Catarata , Exoftalmia/etiologia , Glaucoma de Ângulo Fechado/cirurgia , Hemangioma Cavernoso do Sistema Nervoso Central/etiologia , Humanos , Subluxação do Cristalino/cirurgia , Imageamento por Ressonância Magnética , Masculino , Descolamento Retiniano/etiologia
12.
Sci Rep ; 8(1): 13810, 2018 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-30217996

RESUMO

Metabolic dysfunction in the liver is the cause of numerous pathologies, which are associated with an altered redox state. PASK (PAS Domain Kinase) is a nutrient and bioenergetic sensor. We contend that PASK could act as an oxidative stress sensor in liver and/or control the metabolic balance, playing a role in the mitochondrial homeostasis. Using PASK-deficient mice, we observed that PASK deficiency promotes antioxidant response mechanisms: a lower production of ROS/RNS under non-fasting conditions, overexpression of genes coding to ROS-detoxifying enzymes and mitochondrial fusion proteins (MnSod Gpx, Mfn1 and Opa1), coactivator Ppargc1a, transcription factors (Pparg and FoxO3a) and deacetylase Sirt1. Also, under fasting conditions, PASK deficiency induced the overexpression of Ppargc1a, Ppara, Pparg, FoxO3a and Nrf2 leading to the overexpression of genes coding to antioxidant enzymes such as MnSOD, Cu/ZnSOD, GPx, HO1 and GCLm. Additionally, inducing PINK1 involved in cell survival and mitophagy. These changes kept ROS steady levels and improved the regenerative state. We suggest a new role for PASK as a controller of oxidative stress and mitochondrial dynamics in the liver. In fact, antioxidant response is PASK dependent. PASK-targeting could therefore be a good way of reducing the oxidative stress in order to prevent or treat liver diseases.


Assuntos
Fígado/metabolismo , Proteínas Serina-Treonina Quinases/deficiência , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Antioxidantes/metabolismo , Glucose/metabolismo , Homeostase/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/metabolismo , Dinâmica Mitocondrial/fisiologia , Proteínas Mitocondriais/metabolismo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Sirtuína 1/metabolismo , Superóxido Dismutase/metabolismo , Fatores de Transcrição/metabolismo
13.
Sci Rep ; 8(1): 11091, 2018 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-30038292

RESUMO

The liver controls metabolic homeostasis in response to fasting and refeeding periods. Glucokinase (GCK) adjusts hepatic glucose phosphorylation to blood glucose levels, acting as a glucose sensor. Our objective was to determine whether PAS kinase (PASK), a nutrient sensor, could be affecting the expression or activity of liver GCK and the response to fasting and refeeding states of key hepatic metabolic pathways. PASK-deficient mice have impaired insulin signaling (AKT overactivation). Furthermore, PASK deficiency modified the expression of several transcription factors involved in the adjustment to fasting and refeeding. Foxo1 decreased under fasting conditions, while Ppara and Pparg were overexpressed in PASK-deficient mice. However, PEPCK protein levels were similar or higher, while the expression of Cpt1a decreased in PASK-deficient mice. By contrast, Lxra and Chrebp were overexpressed after refeeding, while the expression of Acc and Fas decreased in PASK-deficient mice. Likewise, with a decreased expression of Gck and increased nuclear location of the complex GCK-GCKR, GCK activity decreased in PASK-deficient mice. Therefore, PASK regulated some of the genes and proteins responsible for glucose sensing, such as glucokinase, and for insulin signalling, affecting glucose and lipid metabolism and consequently certain critical hepatic functions.


Assuntos
Glucoquinase/metabolismo , Fígado/metabolismo , Proteínas Serina-Treonina Quinases/deficiência , Proteínas Adaptadoras de Transdução de Sinal , Animais , Proteínas de Transporte/metabolismo , Jejum , Comportamento Alimentar , Regulação da Expressão Gênica , Glucoquinase/genética , Insulina/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos Endogâmicos C57BL , Fosfoenolpiruvato Carboxiquinase (ATP)/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo
14.
J Clin Invest ; 56(1): 135-45, 1975 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-237936

RESUMO

Gel filtration studies on Bio-Gel P-10 columns of a 50-fold purified porcine duodenal extract revealed a main peak of glucagon-like immunoreactivity (GLI) in the 2,900 mol wt zone and a smaller peak in the 3,500 mol wt zone, the same zone as the pancreatic glucagon marker. Like pancreatic glucagon, samples of 3,500 mol wt material gave essentially identical measurements in radioimmunoassays employing the pancreatic glucagon-specific antiserum 30K and the GLI crossreacting antiserum 78J, whereas the 2,900 mol wt peptide gave 60-fold higher readings in the 78J assay. On disk gel electrophoresis, the 3,500 mol wt fraction, like pancreatic glucagon, migrated at pH 8.3, whereas the 2,900 mol wt peptide remained at the origin; at pH 4.7, the 2,900 mol wt peptide migrated while the 3,500 mol wt immunoreactive peptide and glucagon remained at the origin. Isoelectric focusing revealed the 3,500 mol wt moiety to have an isoelectric point (pI) of 6.2, the same as pancreatic glucagon, whereas the 2,900 mol wt peptide had an pI greater than 10. The glycogenolytic activity of the 3,500 mol wt peptide in the perfused rat liver did not differ significantly from glucagon, and its adenylate cyclase stimulating activity in partially purified liver cell membranes was comparable to that of glucagon; the 2,900 mol wt peptide had less than 20% of these activities. In samples of 3,500 mol wt material subjected to isoelectric focusing, adenylate cyclase-stimulating activity was confirmed to fractions containing 30K immunoreactivity with a pI of 6.2. In samples of 2,900 mol wt material subjected to isoelectric focusing, adenylate cyclase-stimulating activity was confined to fractions containing 78J immunoreactivity with an pI greater than 10. Displacement of [125-I]glucagon from the membranes was limited to these two biologically active fractions. However, the affinity of both pancreatic glucagon and the 3,500 mol wt peptide was an order of magnitude greater than of the 2,900 mol wt peptide. Thus, by all of several biologic, physiocochemical, and immunometric techniques, the 3,500 mol wt gut immunoreactive peptide could not be distinguished from pancreatic glucagon, while the 2,900 mol wt peptide was readily differentiated by all these techniques. "True" A-cells, ultrastructurally indistinguishable from pancreatic A-cells but differing from the A-like cells of the lower bowel, were identified in the gastric fundus of dogs. Their distribution corresponded to that of the 3,500 mol wt immunoreactivity resembling pancreatic glucagon, while the distribution of "A-like cells" in the lower small intestine corresponded to that of GLI.


Assuntos
Sistema Digestório/análise , Glucagon/análise , Adenilato Quinase/metabolismo , Animais , Cromatografia em Gel , Grânulos Citoplasmáticos/análise , Duodeno/análise , Eletroforese Descontínua , Glucagon/imunologia , Glucagon/metabolismo , Glucagon/fisiologia , Concentração de Íons de Hidrogênio , Soros Imunes , Insulina/análise , Focalização Isoelétrica , Peso Molecular , Pâncreas/metabolismo , Coelhos/imunologia , Radioimunoensaio , Suínos , Extratos de Tecidos/análise , Vasopressinas/análise
15.
An Med Interna ; 24(7): 312-6, 2007 Jul.
Artigo em Espanhol | MEDLINE | ID: mdl-18020886

RESUMO

OBJECTIVE: The HICAP study assessed the cardiovascular (CV) global risk and the CV risk factors control in hypertensive patients managed in Primary Care (PC) in Spain. METHODS: Cross-sectional and multilocated study in which each investigator included data from 5 consecutives hypertensive patients. A routine laboratory test and a ECG from the previous 6 months had to be available for each patients CV global risk evaluation, blood pressure (BP) and diabetes control was based on ESH-ESC 2003; lipid profile evaluation was based on NCEP 2001 (ATP III) RESULTS: 1288 PC physicians included 6719 hypertensive patients, and data from 6375 patients were analyzed.64.5% (CI95%: 63.3-65.7) of the hypertensive patients managed in Primary Care showed a high or very high CV global risk.BP was controlled in 39.3% (CI95%: 38.1-40.5) of patients, 10.5% (CI95%: 9.1-11.9)among diabetics. 37.3% (CI95%: 35-38.7) of diabetics showed HbA1c < 6.5% and 18.8% (CI95%: 17.6-20) of dyslipidemic subjects had their LDL-c controlled. The control was lower among the patients at higher CV global risk. CONCLUSIONS: These results demostrate the high proportion of hypertensive patients that present a high CV global risk. The cardiovascular risk factors control, specially among patients at higher CV global risk, is insufficient.


Assuntos
Hipertensão/diagnóstico , Hipertensão/terapia , Atenção Primária à Saúde/normas , Qualidade da Assistência à Saúde , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Espanha
16.
Rev Esp Anestesiol Reanim ; 63(6): 361-4, 2016.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-27062171

RESUMO

Rubinstein-Taybi syndrome (RTS) is a chromosomopathy associated to molecular mutations or microdeletions of chromosome 16. It has an incidence of 1:125,000-700,000 live births. RTS patients present craniofacial and thoracic anomalies that lead to a probable difficult-to-manage airway and ventilation. They also present mental retardation and comorbidity, such as congenital cardiac defects, pulmonary structural anomalies and recurrent respiratory infections, which increase the risk of aspiration pneumonia. Cardiac arrhythmias have been reported after the use of certain drugs such as succinylcholine and atropine, in a higher incidence than in general population. There is an increased risk of postoperative apnea-hypopnea in these patients. We report the anesthetic management in a RTS patient undergoing emergent thoracic surgery due to oesophageal perforation and mediastinitis. Lung isolation was achieved with a bronchial blocker guided with a fiberoptic bronchoscope and one-lung ventilation was performed successfully.


Assuntos
Síndrome de Rubinstein-Taybi , Anestésicos , Humanos , Deficiência Intelectual , Ventilação Monopulmonar , Cirurgia Torácica
17.
Diabetes ; 42(9): 1262-72, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8349037

RESUMO

An inositol phosphoglycan that is the polar head group of a glycosyl phosphatidylinositol has been considered as a putative mediator of insulin action. To gain insight into the functions of this hormone during development, the relationships between insulin, insulin receptors, glycosyl phosphatidylinositol, and inositol phosphoglycan were studied. Glycosyl phosphatidylinositol was isolated and characterized in fetal liver as early as day 15 of intrauterine life. In isolated hepatocytes from fetal and adult rats labeled with [3H]glucosamine, [3H]galactose, or [3H]myo-inositol, these molecules were incorporated into glycosyl phosphatidylinositol. In hepatocytes labeled with [3H]glucosamine and then allowed to react with [1-14C]IAI, the [3H]glycosyl phosphatidylinositol was purified as the 14C-labeled amidinated lipid. Glycosyl phosphatidylinositol molecules from fetal and adult cells were sensitive to hydrolysis by a phosphatidylinositol-specific phospholipase C from B. cereus. The product of this hydrolysis inhibits the activity of a cAMP-dependent protein kinase, whereas this effect was abolished by nitrous acid deamination. In isolated hepatocytes from adult animals, an inverse correlation between extracellular insulin and the number of insulin receptors and the cellular content of glycosyl phosphatidylinositol was observed. However, in fetal hepatocytes insulin failed to reduce the glycosyl-phosphatidylinositol content when labeled either with [1-14C]isethionyl acetimidate or [3H]glucosamine, whereas insulin-like growth factor I produced a significant hydrolysis of glycosyl phosphatidylinositol. Fetal and adult hepatocytes were incubated with insulin or inositol phosphoglycan after which glycogen phosphorylase activities were determined. Inositol phosphoglycan mimicked the action of insulin on both forms of the enzyme from adult hepatocytes, whereas in fetal cells insulin did not change, and purified inositol phosphoglycan reduced the activities of glycogen phosphorylase. These findings suggest a dissociation between insulin receptor occupancy and the expected hormonal effects in fetal hepatocytes. This could be related to alterations at a postreceptor level.


Assuntos
Glicosilfosfatidilinositóis/metabolismo , Insulina/fisiologia , Fígado/metabolismo , Animais , Feminino , Galactose/metabolismo , Glucosamina/metabolismo , Hidrólise , Inositol/metabolismo , Fosfatos de Inositol/metabolismo , Fígado/embriologia , Masculino , Fosforilases/metabolismo , Ratos , Ratos Wistar , Receptor de Insulina/metabolismo
19.
Endocrinology ; 122(5): 1737-45, 1988 May.
Artigo em Inglês | MEDLINE | ID: mdl-3282871

RESUMO

The studies described in this paper were undertaken to characterize the insulin receptors present in the plasma membranes and Golgi fractions of fetal rat liver and to determine their subcellular distribution after the administration of exogenous insulin. Purification patterns of both types of liver membranes from fetal and adult rats were similar, as verified by morphological and biochemical approaches. In both groups insulin binding was significantly greater in plasma membranes than in Golgi fractions. However, in plasma membranes insulin binding was similar in both groups, while in Golgi fractions it was greater in fetal than in adult rats, although the difference was not statistically significant. The modifications in insulin binding reflect changes in the number of receptors, but not in the affinity constants. The time courses of insulin association and dissociation from liver membranes were unaffected by development. Degradation of insulin by liver membranes was lower in fetal than in adult rats, although this does not seem to be responsible for the differences observed in binding. No significant differences in the degradation of insulin receptors between different groups of liver membranes were found. The effects of a single injection of insulin on the subcellular distribution of insulin receptors in liver were examined. Insulin administration to adult rats resulted in a marked decrease in insulin binding in liver plasma membranes but a significant increase in Golgi fractions, occurring within 1.5 min. By contrast, in 21-day-old fetuses insulin injection slightly increased insulin binding to liver plasma membranes at 15 min, while in Golgi fractions an increase in insulin binding was only observed 30 min after insulin injection. These findings suggest that the slow ligand-induced translocation of the insulin receptor from the cell surface to Golgi fractions in the fetus might explain the absence of insulin receptor down-regulation in fetal hepatocytes.


Assuntos
Complexo de Golgi/metabolismo , Insulina/metabolismo , Fígado/metabolismo , Receptor de Insulina/metabolismo , Animais , Glicemia/análise , Fracionamento Celular , Membrana Celular/metabolismo , Sangue Fetal/análise , Insulina/sangue , Cinética , Fígado/embriologia , Masculino , Ratos , Ratos Endogâmicos
20.
Endocrinology ; 139(5): 2363-8, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9564846

RESUMO

Glucagon-like peptide-1 (GLP-1) receptor messenger RNA has been identified in cells considered type II pneumocytes that are involved in the synthesis and secretion of the pulmonary surfactant. In an attempt to open new insights into the control of surfactant secretion, we studied the effects of glucagon-related peptides in this process. Accordingly, type II pneumocytes were isolated from Wistar rat lungs and cultured overnight with [methyl-14C]choline, and then the basal and stimulated secretions of [14C]phosphatidylcholine were measured. GLP-1(7-36)amide stimulated phosphatidylcholine secretion in a concentration-dependent manner in the 1-100 nM range; the concentration of the peptide that produced a half-maximal response was 10 nM. Exendin-4 induced similar effects. No changes were observed when GLP-1-(1-37), GLP-2, or exendin-(9-39) was added to the medium. However, the latter reversed the stimulatory effects of GLP-1-(7-36)amide and exendin-4. A study of the mechanism through which GLP-1-(7-36)amide exerts its stimulatory effect was carried out using different agents that are well known stimulants of phosphatidylcholine secretion. GLP-1-(7-36)amide did not produce any change in the stimulatory effect observed with terbutaline or 8-bromo-cAMP, suggesting the involvement of a cAMP-dependent protein kinase in the stimulatory effect of this peptide on phosphatidylcholine secretion. It was further supported by the use of inhibitors of protein kinases and by the stimulation of cAMP production in type II pneumocytes incubated with either GLP-1-(7-36)amide or exendin-4.


Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Fragmentos de Peptídeos/farmacologia , Surfactantes Pulmonares/metabolismo , Agonistas Adrenérgicos beta/farmacologia , Animais , Calcimicina/farmacologia , ATPases Transportadoras de Cálcio/antagonistas & inibidores , Células Cultivadas , Proteína Quinase Tipo II Dependente de AMP Cíclico , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Glucagon , Peptídeo 1 Semelhante ao Glucagon , Peptídeos Semelhantes ao Glucagon , Cinética , Masculino , Fosfatidilcolinas/metabolismo , Ratos , Ratos Wistar , Terbutalina/farmacologia , Acetato de Tetradecanoilforbol/farmacologia , Tapsigargina/farmacologia
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