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2.
MethodsX ; 12: 102686, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38585179

RESUMO

One of the initial steps in the preprocessing of digital fundoscopy images is the identification of pixels containing relevant information. This can be achieved through different approaches, one of them is implementing background extraction, reducing the set of pixels to be analyzed later in the process. In this work, we present a background extraction method for digital fundoscopy images based on computational topology. By interpreting binarized images as cubical complexes and extracting their homological groups in 1 and 2 dimensions we identify a subset of luminescence values that can be used to binarize the original grayscale image, obtaining a mask to achieve background extraction. This method is robust to noise and suboptimal image quality, facilitating the analytical pipeline in the context of computer aided diagnosis approaches. This method facilitates the segmentation of the background of a digital fundoscopy image, which allows further methods to focus on pixels with relevant information (eye fundus). This tool is best suited to be implemented in the preprocessing stages of the analytical pipeline by computational ophthalmology specialists.•It is robust to noise and low-quality images.•Output provides an ideal scenario for down-the-line analysis by facilitating only relevant pixels in a digital fundoscopy.

3.
Nature ; 433(7026): 629-33, 2005 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-15703747

RESUMO

Agrobacterium is widely considered to be the only bacterial genus capable of transferring genes to plants. When suitably modified, Agrobacterium has become the most effective vector for gene transfer in plant biotechnology. However, the complexity of the patent landscape has created both real and perceived obstacles to the effective use of this technology for agricultural improvements by many public and private organizations worldwide. Here we show that several species of bacteria outside the Agrobacterium genus can be modified to mediate gene transfer to a number of diverse plants. These plant-associated symbiotic bacteria were made competent for gene transfer by acquisition of both a disarmed Ti plasmid and a suitable binary vector. This alternative to Agrobacterium-mediated technology for crop improvement, in addition to affording a versatile 'open source' platform for plant biotechnology, may lead to new uses of natural bacteria-plant interactions to achieve plant transformation.


Assuntos
Bactérias/classificação , Bactérias/genética , Técnicas de Transferência de Genes , Plantas/genética , Plantas/microbiologia , Transformação Genética/genética , Arabidopsis/genética , Arabidopsis/microbiologia , Sequência de Bases , Biotecnologia/métodos , DNA Bacteriano/genética , Vetores Genéticos/genética , Genótipo , Oryza/genética , Oryza/microbiologia , Folhas de Planta/genética , Folhas de Planta/microbiologia , Plantas Geneticamente Modificadas , Plasmídeos/genética , Rhizobium/genética , Simbiose , Nicotiana/genética , Nicotiana/microbiologia
4.
Rev Gastroenterol Mex ; 75(1): 107-11, 2010.
Artigo em Espanhol | MEDLINE | ID: mdl-20423792

RESUMO

Forty-two year-old woman, with no relevant medical history, presented with 3-year burning epigastric pain radiating to right upper quadrant, accompanied by nausea and vomiting, food intolerance and estheatorrea. She was treated by 2 years with H2 blockers. Cholelithiasis was found and laparoscopic cholecystectomy was performed without changes in clinical picture. She presented upper gastrointestinal bleeding secondary to severe esophagitis and gastritis. Proton pump inhibitors at high doses were added to the treatment with partial improvement. Abdominal ultrasound showed tumor in pancreatic head but it was not confirmed by computed tomography. High levels of serum gastrin (17,251 µg/L) were detected. Patient underwent laparotomy and with the aid of ultrasound the mass in the head of the pancreas was localized and resected. Recovery was uneventful. The pathology report was a gastrinoma. At one year follow up, patient remains asymptomatic.


Assuntos
Síndrome de Zollinger-Ellison/diagnóstico , Adulto , Feminino , Humanos
5.
Science ; 158(3806): 1325-6, 1967 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-4168330

RESUMO

Concanavalin A precipitated less than 5 percent of immunoglobulin G from human serum. It reacted with all of 42 myeloma serums of the immunoglobulin G type tested, but no more than approximately 50 percent of the total myeloma protein was ever precipitated. The fact that not all of the protein was precipitated and that the amounts precipitated varied from serum to serum may be interpreted as demonstrating heterogeneity of the carbohydrate in these myeloma proteins. Other glycoproteins precipitated by concanavalin A were identified, and subsequently separated from concanavalin A by chromatography.


Assuntos
Reações Antígeno-Anticorpo , Lectinas , Mieloma Múltiplo/sangue , gama-Globulinas , Eletroforese das Proteínas Sanguíneas , Cromatografia , Glicoproteínas/análise , Humanos , Imunoeletroforese , Mieloma Múltiplo/imunologia , Testes de Precipitina
6.
Science ; 162(3851): 369-71, 1968 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-4175691

RESUMO

Three of 64 IgA immunoglobuilins, derived from plasma cell tumors induced by mineral oil in BALB/c mice, precipitated with species-specific pneumococcus C polysaccharide. A related antigen was also found in group O and some group H streptococci. A difference in ability to precipitate a C polysaccharide from a pneumococcus type XIV was demonstrated between protein 603 which did precipitate and protein 167 which did not precipitate this polysaccharide. Studies of the 167 and 603 proteins showed differences in electrophoretic mobility and polypeptide chains. The antigen-combining site of the 167 and 603 proteins resided on the papain-digestion Fab fragment.


Assuntos
Reações Antígeno-Anticorpo , Precipitação Química , Polissacarídeos Bacterianos , gama-Globulinas/análise , Animais , Cromatografia por Troca Iônica , Imunodifusão , Imunoeletroforese , Endogamia , Camundongos , Óleo Mineral , Neoplasias Experimentais/imunologia , Peptídeos/análise , Plasmocitoma/induzido quimicamente , Plasmocitoma/imunologia , Streptococcus pneumoniae/imunologia
7.
Science ; 168(3935): 1112-5, 1970 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-5462438

RESUMO

Human lymphocytes treated with the plant protein concanavalin A are stimulated to transform into blasts, without developing cytotoxicity for chicken erythrocytes. Prior treatment of lymphocytes with concanavalin A potentiated phytohemagglutinin-induced blast transformation and DNA synthesis but completely inhibited phytohemagglutinin-induced cytotoxicity. Inhibiton was not due to suppression of the mixed lymphocyte-erythrocyte aggregation normally caused by phytohemagglutinin. Inhibition of cytotoxicity was reversible when concanavalin A was removed from the lymphocytes by treatment with methyl-alpha-D-manno-pyranoside after 1 hour but not after 20 hours. The results indicate that blast transformation and cytotoxicity are separate expressions of lymphocyte stimulation.


Assuntos
Transformação Celular Neoplásica , Linfócitos/efeitos dos fármacos , Proteínas de Plantas/farmacologia , Animais , Galinhas , Isótopos do Cromo , Técnicas de Cultura , Eritrócitos/efeitos dos fármacos , Lectinas/farmacologia , Ativação Linfocitária
8.
Eur J Clin Microbiol Infect Dis ; 28(3): 233-42, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18758831

RESUMO

The purpose of this paper is to determine the incidence of fungal colonization and infection in non-neutropenic critically ill patients and to identify factors favoring infection by Candida spp. A total of 1,655 consecutive patients (>18 years of age) admitted for > or = 7 days to 73 medical-surgical Spanish intensive care units (ICUs) participated in an observational prospective cohort study. Surveillance samples were obtained once a week. One or more fungi were isolated in different samples in 59.2% of patients, 94.2% of which were Candida spp. There were 864 (52.2%) patients with Candida spp. colonization and 92 (5.5%) with proven Candida infection. In the logistic regression analysis risk factors independently associated with Candida spp. infection were sepsis (odds ratio [OR] = 8.29, 95% confidence interval [CI] 5.07-13.6), multifocal colonization (OR = 3.49, 95% CI 1.74-7.00), surgery (OR = 2.04, 95% CI 1.27-3.30), and the use of total parenteral nutrition (OR = 4.37, 95% CI 2.16-8.33). Patients with Candida spp. infection showed significantly higher in-hospital and intra-ICU mortality rates than those colonized or non-colonized non-infected (P < 0.001). Fungal colonization, mainly due to Candida spp., was documented in nearly 60% of non-neutropenic critically ill patients admitted to the ICU for more than 7 days. Proven candidal infection was diagnosed in 5.5% of cases. Risk factors independently associated with Candida spp. infection were sepsis, multifocal colonization, surgery, and the use of total parenteral nutrition.


Assuntos
Estado Terminal , Fungos/isolamento & purificação , Micoses/epidemiologia , Adulto , Idoso , Estudos de Coortes , Feminino , Fungos/classificação , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Micoses/microbiologia , Micoses/mortalidade , Estudos Prospectivos , Fatores de Risco , Espanha
9.
Sci Rep ; 8(1): 10524, 2018 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-30002382

RESUMO

Fragaria chiloensis is a strawberry endemic from Chile with attractive white-pink fruit, pleasant aroma and taste. However, this fruit has a limited post-harvest period due to fast softening. Several transcription factors (TFs) are involved in the regulation of fruit ripening, and members of the NAC family have been implicated in cell wall remodeling. FcNAC1 was isolated from F. chiloensis fruit, coding a protein of 332 amino acid residues and displaying a characteristic NAC domain at the N terminus. FcNAC1 protein showed nuclear localization. An increase in transcript level was observed during ripening. A sequence of 1488 bp of FcNAC1 promoter was obtained. In silico analysis identified cis elements able to respond to some hormones and Secondary wall NAC binding elements (SNBE), and responding to auxin and ABA. A structural model of FcNAC1 provided evidence for interaction with DNA sequences containing SNBE, while a dual luciferase assay confirmed the transcriptional activation by FcNAC1 of the promoter of FcPL, a gene involved in cell wall remodeling in F. chiloensis fruit. The results suggest the participation of FcNAC1 during ripening development of strawberry fruit, by regulating pectin metabolism during softening.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Fragaria/fisiologia , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Ácido Abscísico/metabolismo , Parede Celular/metabolismo , Chile , Clonagem Molecular , DNA de Plantas/química , DNA de Plantas/metabolismo , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/isolamento & purificação , Frutas/citologia , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Ácidos Indolacéticos/metabolismo , Simulação de Dinâmica Molecular , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/isolamento & purificação , Regiões Promotoras Genéticas/genética , Domínios e Motivos de Interação entre Proteínas , Fatores de Transcrição/química , Fatores de Transcrição/genética , Fatores de Transcrição/isolamento & purificação
10.
J Clin Invest ; 48(2): 351-8, 1969 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-5812636

RESUMO

Concanavalin A precipitates antihemophilic factor from normal plasma. Combining this precipitation with other techniques, we were able to separate fractions rich in antihemophilic activity from human plasma with rapidity. The molecular weight of antihemophilic factor was estimated to be greater than 2 million. Presumably, antihemophilic factor is a large glycoprotein.


Assuntos
Fator VIII/isolamento & purificação , Proteínas de Plantas , Animais , Precipitação Química , Eletroforese Descontínua , Glicoproteínas , Humanos , Soros Imunes , Técnicas In Vitro , Métodos , Peso Molecular , Coelhos , Espectrofotometria , Ultracentrifugação
11.
J Clin Invest ; 70(2): 329-34, 1982 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-6178755

RESUMO

Peripheral blood T lymphocytes from 29 of 31 patients with rheumatoid arthritis incorporated significant quantities of thymidine when cultured with pooled human immunoglobulin G (IgG). In contrast to the observation of general reactivity to pooled Igg, responses to pooled IgM were rare (3 of 26 patients). None of 11 controls responded to either IgG or IgM. Response to IgG is maximal on day 6 of culture and is dependent on concentration of IgG. The responding cells recognize determinants on monoclonal light chains and/or Fab fragments. Response to light chains follows one of three patterns: preferential response to lambda chains, preferential response to kappa chains, and essentially equal response to either kappa of lambda chains.


Assuntos
Artrite Reumatoide/imunologia , Epitopos , Fragmentos Fab das Imunoglobulinas/imunologia , Imunoglobulina G/imunologia , Cadeias Leves de Imunoglobulina/imunologia , Linfócitos T/imunologia , Divisão Celular , Relação Dose-Resposta a Droga , Humanos , Imunoglobulina M/imunologia , Cinética , Ativação Linfocitária
12.
Arch Esp Urol ; 69(8): 518-526, 2016 Oct.
Artigo em Espanhol | MEDLINE | ID: mdl-27725328

RESUMO

Double J stents are used in Urology in an important number of pathologies. These devices contribute to solve very prevalent pathologies such as upper urinary tract lithiasis. However, there are very frequent symptoms associated with double J catheters that may produce a very important constraint on the quality of life of patients. Although theses symptoms are not severe in most cases, they require medical treatment to be solved in certain patients. Several types of drugs such as analgesics, anti-inflammatories, antibiotics, anticholinergics and alpha-blockers have been used for this pathology, with variable results depending on the authors. We consider the use of certain drugs may help patients to solve the symptoms associated with double J catheters, mainly the first days after insertion. In the mid term, urinary symptoms are associated with problems related to double J catheter, so it is necessary to establish the proper measures to have this devices not loose their physical characteristics, that may condition these adverse symptoms.


Assuntos
Complicações Pós-Operatórias/tratamento farmacológico , Complicações Pós-Operatórias/etiologia , Cateteres Urinários/efeitos adversos , Desenho de Equipamento , Humanos , Complicações Pós-Operatórias/prevenção & controle
13.
Cell Signal ; 8(8): 567-73, 1996 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9115849

RESUMO

Insulin acts on its target tissues by specific interaction with the cell surface insulin receptor (IR). The IR possesses an intrinsic tyrosine kinase (TK) activity which is stimulated by insulin binding. This TK activity is required for many aspects of insulin signalling. We had earlier reported that human plasma alpha 2-HS glycoprotein (alpha 2-HSG) inhibits insulin-stimulated mitogenesis at the level of IR-TK (Mol Endo 7: 1445-1455, 1993). In the present study, using recombinant alpha 2-HSG, which possesses 50-100 times the specific activity of plasma alpha 2-HSG, we have further investigated the molecular basis of this effect. We examined the insulin-stimulated Ras signalling pathway in Chinese Hamster Ovary cells overexpressing the human IR. alpha 2-HSG inhibits insulin-induced tyrosine phosphorylation of IRS-1 and the subsequent association of GRB2, as well as Sos, with IRS-1. This inhibition results in reduced guanine nucleotide exchange in p21ras. alpha 2-HSG also inhibits the stimulation of Raf phosphorylation, in response to insulin, leading to inhibition of MEK activity. In a parallel pathway, alpha 2-HSG also inhibits insulin-induced tyrosine phosphorylation of Shc. However, alpha 2-HSG does not affect any of the metabolic actions of insulin rested in these cells. These results suggest that, while insulin's mitogenic effects can be abolished by inhibition of insulin-induced IR-TK, propagation of signals for metabolic activities might utilize alternate of rescue mechanisms.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Proteínas Sanguíneas/farmacologia , Insulina/farmacologia , Quinases de Proteína Quinase Ativadas por Mitógeno , Receptor de Insulina/metabolismo , Animais , Células CHO , Cricetinae , Proteína Adaptadora GRB2 , Guanosina Trifosfato/metabolismo , Humanos , Proteínas Substratos do Receptor de Insulina , MAP Quinase Quinase 1 , Mitose/efeitos dos fármacos , Fosfoproteínas/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo , Proteínas/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Receptor de Insulina/genética , Proteínas Recombinantes/farmacologia , Transdução de Sinais/efeitos dos fármacos , alfa-2-Glicoproteína-HS
14.
Mol Endocrinol ; 7(11): 1445-55, 1993 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7906861

RESUMO

The insulin-dependent tyrosine kinase activity (TKA) of the insulin receptor (IR) plays an essential role in insulin signaling. Thus, dysregulation of IR-TKA might be an important element in the states of insulin resistance. A phosphorylated rat hepatic glycoprotein (pp63) acting as an inhibitor of IR-TK has been described. In search of the human homolog of pp63, we isolated a cDNA clone from a human liver lambda gt11 cDNA library. DNA sequence analysis reveals identity with the mRNA product of a human gene AHSG encoding a serum protein, alpha 2-Heremans Scmid-glycoprotein (alpha 2HSG), with heretofore unknown physiological function. Northern blot analysis demonstrates a 1.8-kilobase mRNA in human liver and HepG2 hepatoma cells. alpha 2HSG, purified from human serum, specifically inhibits insulin-stimulated IR autophosphorylation in vitro and in vivo as well as exogenous substrate tyrosine phosphorylation. alpha 2HSG also inhibits both insulin-induced tyrosine phosphorylation of IRS-1 and the association of IRS-1 with the p85 subunit of phosphatidylinositol-3 kinase in H-35 hepatoma cells. alpha 2HSG inhibits insulin-dependent mitogenesis, but does not affect insulin-stimulated induction of the metabolic enzyme tyrosine aminotransferase. alpha 2HSG does not compete with insulin for binding to IR. Finally, the action of alpha 2HSG is specific toward the IR-TK; its effect does not extend to insulin-like growth factor-I-stimulated TKA. Our results allow us to assign a biochemical function for human alpha 2HSG, namely regulation of insulin action at the IR-TK level.


Assuntos
Proteínas Sanguíneas/farmacologia , Proteínas Tirosina Quinases/antagonistas & inibidores , Receptor de Insulina/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Células CHO , Divisão Celular/efeitos dos fármacos , Cricetinae , DNA Complementar/genética , Indução Enzimática/efeitos dos fármacos , Glicoproteínas/química , Humanos , Células L , Fígado/metabolismo , Camundongos , Dados de Sequência Molecular , Fosforilação/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Ratos , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Células Tumorais Cultivadas , Tirosina Transaminase/biossíntese , alfa-2-Glicoproteína-HS
15.
Endocrinology ; 105(2): 391-401, 1979 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-572292

RESUMO

Concanavalin A (Con A) inhibits fusion of trypsin-treated myoblasts. This inhibition is reversed by the addition of supraphysiological concentrations (4 micrograms/ml) of insulin either during continuous presence in culture or by pulse additions at 36 and 48 h of culture, just before the time that cultures not treated with Con A undergo myoblast fusion. This reversal is not due to the mitogenic effects of insulin. Under reversal conditions, no specific displacement of bound [125I]iodo-Con A was detected nor did insulin stimulate metabolite uptake. Cell surface replicas of hemocyanin-tagged Con A showed that insulin reversal of the inhibition of myotube formation correlated with the alteration of Con A-binding sites from a clustered configuration present in the inhibited cells to a dispersed state correlated with normal myotube formation. Although a causal relationship has yet to be shown, the data suggest that insulin-mediated reversal of Con A inhibition of myoblast fusion may be related to the ability of insulin at supraphysiological levels to alter the translational mobility of cell surface components containing glucose and/or mannose residues capable of binding Con A. Evidence is presented which suggests that insulin and Con A share common binding sites, since in the physiological range of insulin concentrations (1 ng/ml), Con A pretreatments results in an inhibition of specific [125I]iodo-insulin binding, and antagonistic interactions of insulin and Con A on metabolite uptake and cell proliferation occur. Thus, it appears that the insulin receptors of developing skeletal muscle are glycoproteins containing glycopyranosides.


Assuntos
Concanavalina A/farmacologia , Insulina/farmacologia , Músculos/metabolismo , Receptor de Insulina/metabolismo , Receptores de Concanavalina A/metabolismo , Receptores de Droga/metabolismo , Animais , Cálcio/farmacologia , Diferenciação Celular/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Embrião de Galinha , Cinética , Músculos/efeitos dos fármacos , Receptor de Insulina/efeitos dos fármacos , Receptores de Concanavalina A/efeitos dos fármacos
16.
Invest Ophthalmol Vis Sci ; 24(2): 237-42, 1983 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-6826327

RESUMO

The role of complement components C3 and C5 was examined in murine corneal infection induced by Pseudomonas aeruginosa. DBA/2 and Swiss-Webster mice are naturally resistant to experimental P. aeruginosa corneal infection. Mice of these two strains are able to restore a clear cornea within 4-6 weeks following Pseudomonas corneal challenge and are genetically deficient in the fifth component of complement. In contrast, ocular infection of congenic C5-deficient B10.D2o/Sn or normocomplementemic B10.D2n/Sn mice results in an identical pattern of susceptibility in which corneal perforation and phthisis bulbi occur. Taken together, these results indicate that C5 plays little or no role in susceptibility or resistance to Pseudomonas eye infection. In contrast, depletion of C3 in normally resistant DBA/2 mice using cobra venom factor (CoVF) diminishes the ability of these mice to restore a clear cornea following Pseudomonas infection. A single inoculation of CoVF, 24 hours prior to ocular challenge, is as effective in altering the response of DBA/2 mice as is continuous depletion of C3 during the course of infection using multiple inoculations of CoVF. Mice that are unable to clear Pseudomonas ocular infection following CoVF treatment regain this ability when the contralateral eye is infected after recovery of normal levels of C3. Depletion of C3 by CoVF treatment of DBA/2 mice, which had previously restored a clear cornea following Pseudomonas eye infection, again renders these mice susceptible.


Assuntos
Complemento C3/análise , Complemento C5/análise , Ceratite/imunologia , Infecções por Pseudomonas/imunologia , Animais , Venenos Elapídicos/imunologia , Feminino , Ceratite/etiologia , Camundongos , Camundongos Endogâmicos DBA , Camundongos Endogâmicos
17.
Mol Cell Endocrinol ; 164(1-2): 87-98, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11026561

RESUMO

Human fetuin, [alpha2-Heremans Schmid Glycoprotein (alpha2-HSG)], is a natural inhibitor of insulin receptor tyrosine kinase activity (IR-TKA). Previously, we have demonstrated that alpha2-HSG inhibits the mitogenic pathway without affecting the metabolic arm of insulin signal transduction. In this study, we demonstrate the time-course and specificity of inhibition, its interaction with IR and probable physiological role. In intact rat1 fibroblasts overexpressing the human insulin receptor (HIRc B), incubation of recombinant human alpha2-HSGbac (1.8 microM) inhibited insulin-induced IR autophosphorylation by over 80%. This inhibitory effect of alpha2-HSGbac on insulin-induced IR autophosphorylation was blunted by half in 60 min. Interestingly, alpha2-HSGbac at similar concentrations (0.9 or 1.8 microM), had no effect on EGF- or IGF-I-induced cognate receptor autophosphorylation. Anti-alpha2-HSG immunoprecipitates of alpha2-HSGbac-treated HIRc B cell lysates demonstrated the presence of IR. Our data suggest that alpha2-HSGbac preferentially interacts with the activated IR. To further characterize the site(s) of interaction, the effect of alpha2-HSGbac on trypsin-treated IR autophosphorylation was studied. Trypsin-treatment of intact HIRc B cells results in proteolysis of the IR alpha-chain and constitutive activation of IR-TKA. We demonstrate that alpha2-HSGbac (0.1 microM) completely inhibited trypsin-activated IR autophosphorylation and TKA in vitro indicating that this effect was not mediated by its interaction with the proximal 576 amino acid residues of the IR alpha-subunit. The physiological relevance of these observations was explored by characterizing the effects of alpha2-HSG injection in rats. Alpha2-HSGbac (2 microM), acutely injected through the portal vein of normal rats, inhibited insulin-stimulated IR autophosphorylation and IRS-1 phosphorylation in liver and hindlimb muscle. Taken together our results suggest that alpha2-HSG, by interacting with IR, specifically inhibits insulin-stimulated IR autophosphorylation and may play a physiological role in the regulation of insulin signaling.


Assuntos
Proteínas Sanguíneas , Cistatinas/fisiologia , Receptor de Insulina/fisiologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , alfa-Fetoproteínas/fisiologia , Animais , Cistatinas/química , Cistatinas/farmacologia , Humanos , Masculino , Fosforilação/efeitos dos fármacos , Ligação Proteica , Proteínas Tirosina Quinases/antagonistas & inibidores , Ratos , Ratos Wistar , Receptor de Insulina/química , Fatores de Tempo , alfa-2-Glicoproteína-HS , alfa-Fetoproteínas/química , alfa-Fetoproteínas/farmacologia
18.
FEMS Microbiol Lett ; 68(2): 231-6, 1991 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-1778444

RESUMO

Growth conditions play a major role in expression of virulence by Shigella spp. both in vitro (adherence and internalization in eukaryotic host cells) and in vivo (keratoconjunctivitis). Optimized expression of virulence required anaerobic growth to log phase in particular media such as brain heart infusion broth. Kinetic studies of guinea pig eye infections showed that as few as 2 x 10(5) S. dysenteriae CG097 or S. flexneri M90T, grown under these optimized conditions, produced keratoconjunctivitis in 15 h. In vitro studies demonstrated that adherence to and invasion of Henle 407 cells, at 37 degrees C, by organisms grown under these optimized conditions, were significantly greater than when organisms were grown aerobically under the same conditions.


Assuntos
Shigella dysenteriae/patogenicidade , Anaerobiose , Animais , Aderência Bacteriana , Linhagem Celular , Meio Ambiente , Cobaias , Células HeLa , Humanos , Ceratoconjuntivite/microbiologia , Cinética , Shigella dysenteriae/crescimento & desenvolvimento , Shigella flexneri/patogenicidade , Virulência
19.
FEMS Microbiol Lett ; 67(3): 323-8, 1991 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-1769541

RESUMO

Evidence is presented that a high level Shiga toxin-producing strain Shigella dysenteriae 60R adheres to and invades the epithelial cell lines Hct8 and Henle 407. The invasive phenotype of S. dysenteriae 60R differs in four ways from the heretofore studied invasive Shigella phenotypes. First, S. dysenteriae 60R lacks the virulence plasmid characteristic of other invasive Shigella spp. and enteroinvasive Escherichia coli. Second, hybridization studies show that the known ipa genes are neither present in the chromosome nor in the small plasmid of 60R. Third, 60R adheres to and invades Hct8 and Henle 407 cells at 37 degrees C as well as at 30 degrees C. Fourth, the phenotype of adherence and invasion of 60R is remarkably stable, even during prolonged growth in laboratory media and storage.


Assuntos
Aderência Bacteriana , Plasmídeos , Shigella dysenteriae/patogenicidade , Antígenos de Bactérias/genética , Linhagem Celular , Humanos , Microscopia Eletrônica , Shigella dysenteriae/genética , Shigella dysenteriae/ultraestrutura , Temperatura , Virulência/genética
20.
Brain Res Dev Brain Res ; 97(2): 153-68, 1996 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-8997500

RESUMO

Although the participation of the floor plate (FP) in the differentiation of neurons in the ventral spinal cord is well established, the function of the FP at the level of the hindbrain is not known. The present investigation was focused on the FP of the rat hindbrain. We used an antibody specifically labeling the rat FP (FP4) and an antiserum raised against the secretory glycoproteins of the subcommissural organ that also reacts with an intracellular material in the FP. Immunocytochemical and ultrastructural evidence was obtained indicating that the rostralmost end of the FP, at the metencephalon, is a highly specialized gland which differentiates early and undergoes regression before birth. The material(s) secreted by these FP cells appear to be transported downward into their basal processes, and upward into ventricular protrusions. It is proposed that the former would participate in the differentiation of the serotonergic neurons, and the latter could be released into the ventricle and reach distant targets. Furthermore, evidence is presented supporting the occurrence of regional and temporal specializations of the FP.


Assuntos
Rombencéfalo/embriologia , Animais , Diferenciação Celular/fisiologia , Desenvolvimento Embrionário e Fetal/fisiologia , Imuno-Histoquímica , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Neurônios/química , Neurônios/ultraestrutura , Ratos , Ratos Sprague-Dawley , Rombencéfalo/química , Rombencéfalo/ultraestrutura , Serotonina/análise , Órgão Subcomissural/química
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