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1.
Opt Express ; 31(24): 40836-40844, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-38041374

RESUMO

The criteria for achieving adjustable rotation of optical vortices are analyzed and used to design a diode-pumped solid-state laser that incorporates intracavity second harmonic generation within a concave-flat cavity to produce frequency-doubled Hermite-Gaussian (FDHG) modes. These FDHG modes are subsequently employed to generate various structured lights containing 2, 4, and 6 nested vortices using an external cylindrical mode converter. Through theoretical exploration, we propose that increasing the radius of curvature of the concave mirror and extending the cavity length can enhance the rotational angles of multiple vortices by expanding the adjustable range of phase shift for FDHG modes. Moreover, theoretical analyses assess vortex rotation concerning the positions of a nonlinear medium, successfully validating the experimental observations and elucidating the phase structures of the transformed beams.

2.
J Appl Microbiol ; 113(4): 807-14, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22805203

RESUMO

AIMS: This study examined the biotransformation pathway of ginsenoside Rb(1) by the fungus Esteya vermicola CNU 120806. METHODS AND RESULTS: Ginsenosides Rb(1) and Rd were extracted from the root of Panax ginseng. Liquid fermentation and purified enzyme hydrolysis were employed to investigate the biotransformation of ginsenoside Rb(1) . The metabolites were identified and confirmed using NMR analysis as gypenoside XVII and gypenoside LXXV. A mole yield of 95·4% gypenoside LXXV was obtained by enzymatic conversion (pH 5·0, temperature 50°C). Ginsenoside Rd was used to verify the transformation pathway under the same reaction condition. The product Compound K (mole yield 49·6%) proved a consecutive hydrolyses occurred at the C-3 position of ginsenoside Rb(1) . CONCLUSIONS: Strain CNU 120806 showed a high degree of specific ß-glucosidase activity to convert ginsenosides Rb(1) and Rd to gypenoside LXXV and Compound K, respectively. The maximal activity of the purified glucosidase for ginsenosides transformation occurred at 50°C and pH 5·0. Compared with its activity against pNPG (100%), the ß-glucosidase exhibited quite lower level of activity against other aryl-glycosides. Enzymatic hydrolysate, gypenoside LXXV and Compound K were produced by consecutive hydrolyses of the terminal and inner glucopyranosyl moieties at the C-3 carbon of ginsenoside Rb(1) and Rd, giving the pathway: ginsenoside Rb(1) → gypenoside XVII → gypenoside LXXV; ginsenoside Rd→F(2) →Compound K, but did not hydrolyse the 20-C, ß-(1-6)-glucoside of ginsenoside Rb(1) and Rd. SIGNIFICANCE AND IMPACT OF THE STUDY: The results showed an important practical application on the preparation of gypenoside LXXV. Additionally, this study for the first time provided a high efficient preparation method for gypenoside LXXV without further conversion, which also gives rise to a potential commercial enzyme application.


Assuntos
Ginsenosídeos/metabolismo , Ophiostomatales/metabolismo , Biotransformação , Fermentação , Glicosídeos/metabolismo , Gynostemma/metabolismo , Hidrólise , Ophiostomatales/enzimologia , Panax/química , Extratos Vegetais/metabolismo , Raízes de Plantas/química , beta-Glucosidase/metabolismo
3.
Biochem Biophys Res Commun ; 378(2): 149-51, 2009 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-19013436

RESUMO

Wnt signaling pathway has been divided into two subclasses: the canonical pathway (Wnt/beta-catenin pathway) and the non-canonical pathway. It has been proven that Wnt/beta-catenin pathway can enhance wound healing, and some glycoprotein of Wnt family may directly or indirectly improve wound healing.


Assuntos
Proteínas Wnt/metabolismo , Cicatrização , Humanos , Transdução de Sinais , beta Catenina/metabolismo
4.
Drug Alcohol Rev ; 24(6): 525-36, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16361209

RESUMO

Alcoholism is a serious problem throughout the world. The development of alcoholism remedies have medical, social and economical significance. In view of the pitfalls of psychological dependence and adverse behavioural effects of synthetic drugs, the development of low toxicity and high efficiency medicines derived from natural products exhibits expansive market prospects. Based on these considerations, we summarize briefly folk application of traditional hangover remedies and clinical application of herbal complex and patent medicines for alcoholism treatment. We have reviewed the effects of natural medicines on intake, absorption and metabolism of alcohol, as well as the protective effects on alcohol-induced acute and chronic tissue injury.


Assuntos
Alcoolismo/terapia , Medicina Tradicional , Fitoterapia , Preparações de Plantas , Síndrome de Abstinência a Substâncias/terapia , Animais , Ásia , Ensaios Clínicos como Assunto , Medicamentos de Ervas Chinesas/uso terapêutico , Etanol/metabolismo , Flavonóis/uso terapêutico , Medicina Herbária , Humanos , Hypericum , Ibogaína/uso terapêutico , Extratos Vegetais , Substâncias Protetoras/uso terapêutico , Pueraria , Ratos , Salvia miltiorrhiza
5.
Appl Environ Microbiol ; 67(11): 5190-6, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11679344

RESUMO

Natural genetic transformation offers a direct route by which synthetic gene constructs can be placed into the single circular chromosome of Streptococcus pneumoniae. However, the lack of a general negative-selection marker has hampered the introduction of constructs that do not confer a selectable phenotype. A 1.3-kb cassette was constructed comprising a kanamycin (Kn) resistance marker (kan) and a counterselectable rpsL(+) marker. The cassette conferred dominant streptomycin (Sm) sensitivity in an Sm-resistant background in S. pneumoniae. It was demonstrated that it could be used in a two-step transformation procedure to place DNA of arbitrary sequence at a chosen target site. The first transformation into an Sm-resistant strain used the cassette to tag a target gene on the chromosome by homologous recombination while conferring Kn resistance but Sm sensitivity on the recombinant. Replacement of the cassette by an arbitrary segment of DNA during a second transformation restored Sm resistance (and Kn sensitivity), allowing construction of silent mutations and deletions or other gene replacements which lack a selectable phenotype. It was also shown that gene conversion occurred between the two rpsL alleles in a process that depended on recA and that was susceptible to correction by mismatch repair.


Assuntos
Marcadores Genéticos , Proteínas Ribossômicas/genética , Seleção Genética , Streptococcus pneumoniae/genética , Transformação Bacteriana , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Conversão Gênica , Resistência a Canamicina/genética , Recombinação Genética , Streptococcus pneumoniae/efeitos dos fármacos , Estreptomicina/farmacologia
6.
J Cell Biochem ; 82(4): 610-8, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11500939

RESUMO

Insulin-like growth factor II (IGF-II) plays a key role in mitogenesis during development and tumorigenesis and is believed to exert its mitogenic functions mainly through the IGF-I receptor. Recently, we identified the insulin receptor isoform A (IR(A)) as an additional high affinity receptor for IGF-II in both fetal and cancer cells. Here we investigated the mitogenic signaling of IGF-II via the Akt/Glycogen synthase kinase 3 (Gsk3) axis employing R-IR(A) cells that are IGF-I receptor null mouse embryonic fibroblasts expressing the human IR(A). IGF-II induced activation of the proto-oncogenic serine kinase Akt, reaching maximal at 5-10 min. IGF-II also caused the rapid and sustained deactivation of glycogen synthase kinase 3-beta (Gsk3beta), reaching maximal at 1-3 min, shortly preceding, therefore, maximal activation of Akt. Under our conditions, IGF-II and insulin induced 70-80% inhibition of Gsk3betaactivity. In these cells IGF-II also deactivated Gsk3alpha although less effectively than Gsk3beta. In parallel experiments, we found that IGF-II induced transient activation of extracellular-signal-regulated kinases (Erk) reaching maximal at 5-10 min and decreasing thereafter. Time courses and potencies of regulation of both mitogenic pathways (Akt/Gsk3beta and Erk) by IGF-II via IR(A) were similar to those of insulin. Furthermore, IGF-II like insulin effectively stimulated cell cycle progression from the G0/G1 to the S and G2/M phases. Interestingly, AP-1-mediated gene expression, that was reported to be negatively regulated by Gsk3beta was only weakly increased after IGF-II stimulation. Our present data suggest that the coordinated activation or deactivation of Akt, Gsk3beta, and Erk may account for IGF-II mitogenic effects and support an active role for IR(A) in IGF-II action.


Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Fator de Crescimento Insulin-Like II/farmacologia , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas/metabolismo , Receptor de Insulina/metabolismo , Animais , Antígenos CD , Ciclo Celular , Linhagem Celular , Quinase 3 da Glicogênio Sintase , Quinases da Glicogênio Sintase , Humanos , Insulina/farmacologia , Cinética , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Proto-Oncogênicas c-akt , Receptor de Insulina/genética , Fator de Transcrição AP-1/metabolismo , Ativação Transcricional , Transfecção
7.
Am J Physiol Endocrinol Metab ; 280(3): E428-35, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11171597

RESUMO

Glucosamine induced insulin resistance in 3T3-L1 adipocytes, which was associated with a 15% decrease in cellular ATP content. To study the role of ATP depletion in insulin resistance, we employed sodium azide (NaN3) and dinitrophenol (DNP), which affect mitochondrial oxidative phosphorylation, to achieve a similar 15% ATP depletion. Unlike glucosamine, NaN3 and DNP markedly increased basal glucose transport, and the increased basal glucose transport was associated with increased GLUT-1 content in the plasma membrane without changes in total GLUT-1 content. These agents, like glucosamine, did not affect the early insulin signaling that is implicated in insulin stimulation of glucose transport. In cells with a severe 40% ATP depletion, basal glucose transport was similarly elevated, and insulin-stimulated glucose transport was similar in cells with 15% ATP depletion. In these cells, however, early insulin signaling was severely diminished. These data suggest that cellular ATP depletion by glucosamine, NaN3, and DNP exerts differential effects on basal and insulin-stimulated glucose transport and that ATP depletion per se does not induce insulin resistance in 3T3-L1 adipocytes.


Assuntos
Trifosfato de Adenosina/metabolismo , Adipócitos/metabolismo , Glucose/metabolismo , Resistência à Insulina , Insulina/metabolismo , Transdução de Sinais , Células 3T3 , Adipócitos/efeitos dos fármacos , Animais , Transporte Biológico/efeitos dos fármacos , Membrana Celular/metabolismo , Dinitrofenóis/farmacologia , Transporte de Elétrons/efeitos dos fármacos , Glucosamina/farmacologia , Transportador de Glucose Tipo 1 , Guanosina/análogos & derivados , Guanosina/metabolismo , Hexoquinase/metabolismo , Camundongos , Mitocôndrias/metabolismo , Proteínas de Transporte de Monossacarídeos/metabolismo , Fosforilação Oxidativa/efeitos dos fármacos , Azida Sódica/farmacologia
8.
Biochim Biophys Acta ; 1475(3): 225-30, 2000 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-10913820

RESUMO

In insulin-sensitive L6 myocytes, insulin stimulated glycogen synthesis in a dose-dependent manner and lithium further stimulated glycogen synthesis at all insulin concentrations. Lithium alone at 20 mM stimulated glycogen synthesis to the degree similar to the maximal insulin response. Effects of lithium and insulin were fully additive for both glycogen synthesis and glycogen synthase activity. In L6 myocytes, insulin increased phosphorylation of Akt1 and glycogen synthase kinase-3 alpha and beta (GSK-3 alpha and beta), resulting in its activation and inactivation, respectively. Unlike insulin, lithium directly inhibited GSK-3 (both alpha and beta) without affecting phosphorylation of GSK-3. Moreover, lithium in vitro could further inhibit enzyme activity of GSK-3 (both alpha and beta) that was isolated from insulin-stimulated cells (thus already phosphorylated and inactivated by insulin). In summary, insulin increases glycogen synthesis by the Akt1/GSK-3/glycogen synthase pathway, but lithium increases glycogen synthesis by direct inhibition of GSK-3 in L6 myocytes. Inhibitory effects of lithium and insulin on GSK-3 (both alpha and beta) were additive, which may account, at least in part, for their additive effects on glycogen synthase activity and glycogen synthesis in L6 myocytes.


Assuntos
Glicogênio/biossíntese , Insulina/farmacologia , Lítio/farmacologia , Músculos/efeitos dos fármacos , Proteínas Proto-Oncogênicas , Animais , Proteínas Quinases Dependentes de Cálcio-Calmodulina/antagonistas & inibidores , Células Cultivadas , Sinergismo Farmacológico , Ativação Enzimática/efeitos dos fármacos , Glicogênio Sintase/metabolismo , Quinase 3 da Glicogênio Sintase , Quinases da Glicogênio Sintase , Músculos/metabolismo , Fosforilação/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt
9.
Biochem Biophys Res Commun ; 272(3): 953-8, 2000 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-10860857

RESUMO

In rat liver derived HTC cells transfected with and expressing human insulin receptors, there are multiple p60-70 proteins that are tyrosine phosphorylated following insulin treatment of cells. Employing antibodies to insulin receptor substrate 3 (alpha-IRS-3), we found that IRS-3 is a major p60 phosphoprotein that is tyrosine phosphorylated following insulin treatment of cells and interacts with phosphatidylinositol-3-kinase (PI3K). Majority of IRS-3 when phosphorylated appears to interact with PI3K. Tyrosine phosphorylation of IRS-3 is robust at 2 min and steadily increases up to 30-90 min of insulin treatment. Following insulin treatment of cells, some high molecular weight phosphoproteins are coimmunoprecipitated with alpha-IRS-3. In summary, IRS-3 is the major p60 protein that is tyrosine phosphorylated and interacts with PI3K in HTC rat liver derived cells following insulin treatment of cells. Unlike related IRS-1/2 that is transiently phosphorylated, IRS-3 shows robust and prolonged tyrosine phosphorylation upon insulin treatment of cells and may play a role in delayed and/or prolonged insulin actions.


Assuntos
Fosfoproteínas/metabolismo , Animais , Linhagem Celular , Humanos , Insulina/farmacologia , Proteínas Substratos do Receptor de Insulina , Fígado/citologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Peso Molecular , Fosfatidilinositol 3-Quinases/química , Fosfatidilinositol 3-Quinases/metabolismo , Fosfoproteínas/química , Fosforilação/efeitos dos fármacos , Fosfotirosina/metabolismo , Testes de Precipitina , Ligação Proteica/efeitos dos fármacos , Ratos , Transdução de Sinais/efeitos dos fármacos , Fatores de Tempo , Transfecção
10.
Am J Surg ; 179(2): 111-3, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10773145

RESUMO

BACKGROUND: Many studies have concluded that delayed or interval laparoscopic cholecystectomy (LC) in patients with acute cholecystitis (AC) demonstrated higher conversion rates and complication rates compared with early LC. However, if the acutely inflamed gallbladder is decompressed by emergent percutaneous gallbladder drainage (PGBD), it may decrease the technical difficulty of LC allowing successful delayed LC when the patient is in better condition. The purpose of this retrospective study was to assess the outcomes of delayed LC following PGBD in patients with AC. METHODS: A total of 72 LC for AC were divided into PGBD (n = 27) and non-PGBD groups (n = 45). The PGBD group had delayed LC (after 72 hours of admission). Thirty-two non-PGBD patients had early LC (within 72 hours of admission) and 13 non-PGBD had delayed LC. Outcome of delayed LC for the PGBD group was assessed by LC time, conversion rate, morbidity rate, and hospital stay, and compared with that of the non-PGBD group. RESULTS: Compared with early and delayed LC of the non-PGBD group, the PGBD group showed longer LC time (median 110 minutes versus 87.5 minutes versus 85 minutes, P <0. 05), a little lower conversion rate (15% versus 25% versus 23%), similar morbidity rate (15% versus 9% versus 15%), and prolonged hospital stay (13 days versus 7 days versus 10 days). CONCLUSIONS: PGBD did not significantly improve the outcome of LC for AC as assessed by conversion and morbidity rate and hospital stay compared with no PGBD. Thus, we can conclude that although PGBD is a safe and effective emergency procedure for AC, it should be limited to higher risk groups such as elderly or critically ill patients and to acalculous cholecystitis.


Assuntos
Colecistectomia Laparoscópica , Colecistite/cirurgia , Drenagem/métodos , Vesícula Biliar/cirurgia , Doença Aguda , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Colecistectomia , Colecistectomia Laparoscópica/efeitos adversos , Estado Terminal , Descompressão Cirúrgica , Feminino , Hospitalização , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Admissão do Paciente , Estudos Retrospectivos , Fatores de Risco , Segurança , Fatores de Tempo , Resultado do Tratamento
11.
Am J Physiol Endocrinol Metab ; 278(1): E103-12, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10644543

RESUMO

To study molecular mechanisms for glucosamine-induced insulin resistance, we induced complete and reversible insulin resistance in 3T3-L1 adipocytes with glucosamine in a dose- and time-dependent manner (maximal effects at 50 mM glucosamine after 6 h). In these cells, glucosamine impaired insulin-stimulated GLUT-4 translocation. Glucosamine (6 h) did not affect insulin-stimulated tyrosine phosphorylation of the insulin receptor and insulin receptor substrate-1 and -2 and weakly, if at all, impaired insulin stimulation of phosphatidylinositol 3-kinase. Glucosamine, however, severely impaired insulin stimulation of Akt. Inhibition of insulin-stimulated glucose transport was correlated with that of Akt activity. In these cells, glucosamine also inhibited insulin stimulation of p70 S6 kinase. Glucosamine did not alter basal glucose transport and insulin stimulation of GLUT-1 translocation and mitogen-activated protein kinase. In summary, glucosamine induced complete and reversible insulin resistance in 3T3-L1 adipocytes. This insulin resistance was accompanied by impaired insulin stimulation of GLUT-4 translocation and Akt activity, without significant impairment of upstream molecules in insulin-signaling pathway.


Assuntos
Adipócitos/efeitos dos fármacos , Adipócitos/fisiologia , Glucosamina/farmacologia , Resistência à Insulina , Proteínas Musculares , Proteínas Serina-Treonina Quinases , Células 3T3 , Animais , Membrana Celular/metabolismo , Desoxiglucose/farmacocinética , Relação Dose-Resposta a Droga , Transportador de Glucose Tipo 4 , Insulina/farmacologia , Proteínas Substratos do Receptor de Insulina , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Proteínas de Transporte de Monossacarídeos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Fosfoproteínas/metabolismo , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt , Receptor de Insulina/metabolismo , Proteínas Quinases S6 Ribossômicas/metabolismo , Tirosina/metabolismo
12.
J Nat Prod ; 62(11): 1554-7, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10579872
13.
Angiogenesis ; 3(2): 117-23, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-14517429

RESUMO

Aloe vera gel has a beneficial effect on wound healing. Because angiogenesis is an essential process in wound healing, we hypothesized that Aloe vera gel might contain potent angiogenic compounds. Here we demonstrate that Aloe vera gel and its extracts are angiogenic on the chorioallantoic membrane (CAM) of chick embryo. Out of the three compounds purified from the final fraction of Aloe vera gel, beta-sitosterol showed a potent angiogenic activity in the CAM assay. In the presence of heparin, beta-sitosterol stimulated neovascularization in the mouse Matrigel plug assay and the motility of human umbilical vein endothelial cells in an in vitro wound migration assay. Thus beta-sitosterol is a novel plant-derived angiogenic factor which may have potential pharmaceutical applications for the management of chronic wounds.

14.
Chem Pharm Bull (Tokyo) ; 46(7): 1140-3, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9692221

RESUMO

In order to quantify saikosaponin a (SSA), one of the major active components of Bupleuri Radix, a competitive and indirect ELISA method was developed. High titer rabbit polyclonal antibodies (pAbs) were raised against a conjugate of SSA and bovine serum albumin, coupled with a periodate oxidation method. SSA competitively inhibited the binding of rabbit anti-SSA pAbs to SSA-ovalbumin on the solid phase, a coated antigen on the well. The quantity of pAbs bound to the well was monitored using a peroxidase-conjugated anti-rabbit IgG as a secondary antibody, and tetramethylbenzidine solution as a substrate. The measuring range extended from 50 pg/ml to 20 ng/ml of SSA, with a detection limit of 40 pg/ml (5.13 pM). Antibodies showed some cross-reactivity with saikosaponin c (12.74%). However, the antibodies showed only slight cross-reactivities with saikosaponin d (0.3%), which differs from SSA only in the stereochemistry of the 16-hydroxyl group, and the artificial saikosaponins, saikosaponin b1 (2.1%) and saikosaponin g (0.53%). The specific and sensitive ELISA is especially suited for determination of SSA in samples when only small quantities of materials can be extracted for analysis.


Assuntos
Anti-Inflamatórios não Esteroides/análise , Ácido Oleanólico/análogos & derivados , Plantas Medicinais/química , Sapogeninas/análise , Saponinas , Animais , Anti-Inflamatórios não Esteroides/farmacocinética , Especificidade de Anticorpos , Sequência de Carboidratos , Cromatografia Líquida de Alta Pressão , Ensaio de Imunoadsorção Enzimática , Ovalbumina/química , Coelhos/imunologia , Sapogeninas/farmacocinética
15.
J Cell Biochem ; 70(2): 268-80, 1998 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-9671232

RESUMO

In many human breast cancers and cultured cell lines, insulin receptor expression is elevated, and insulin, via its own insulin receptor, can stimulate cell growth. It has recently been demonstrated that the enzyme phosphatidylinositol-3-kinase (PI3-K) mediates various aspects of insulin receptor signaling including cell growth. In order to understand the mechanisms for insulin-stimulated cell growth in human breast cancer, we measured insulin-stimulable PI3-K activity in a non-transformed breast epithelial cell line, MCF-10A, and in two malignantly transformed cell lines, ZR-75-1 and MDA-MB157. All three cell lines express comparable amounts of insulin receptors whose tyrosine autophosphorylation is increased by insulin, and in these cell lines insulin stimulates growth. In MDA-MB157 and MCF-10A cells, insulin stimulated PI3-K activity three- to fourfold. In ZR-75-1 cells, however, insulin did not stimulate PI3-K activity. In ZR-75-1 cells PI3-K protein was present, and its activity was stimulated by epidermal growth factor, suggesting that there might be a defect in insulin receptor signaling upstream of PI3-K and downstream of the insulin receptor. Next, we studied insulin receptor substrate-1 (IRS-1), a major endogenous substrate for the insulin receptor which, when tyrosine is phosphorylated by the insulin receptor, interacts with and activates PI3-K. In ZR-75-1 cells, there were reduced levels of protein for IRS-1. In these cells, both Shc tyrosine phosphorylation and mitogen-activated protein kinase (MAP-K) activity were increased by the insulin receptor (indicating that the p21ras pathway may account for insulin-stimulated cell growth in ZR-75-1 cells). The PI3-K inhibitor LY294002 (50 microM) reduced insulin-stimulated growth in MCF-10A and MDA-MB157 cell lines, whereas it did not modify insulin effect on ZR-75-1 cell growth. The MAP-K/Erk (MEK) inhibitor PD98059 (50 microM) consistently reduced insulin-dependent growth in all three cell lines. Taken together, these data suggest that in breast cancer cells insulin may stimulate cell growth via PI3-K-dependent or-independent pathways.


Assuntos
Divisão Celular/efeitos dos fármacos , Insulina/farmacologia , Quinases de Proteína Quinase Ativadas por Mitógeno , Fosfatidilinositol 3-Quinases/metabolismo , Receptor de Insulina/metabolismo , Neoplasias da Mama/enzimologia , Neoplasias da Mama/patologia , Proteínas Quinases Dependentes de Cálcio-Calmodulina/antagonistas & inibidores , Divisão Celular/fisiologia , Linhagem Celular Transformada , Cromonas/farmacologia , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Flavonoides/farmacologia , Humanos , Insulina/metabolismo , Proteínas Substratos do Receptor de Insulina , MAP Quinase Quinase 1 , Morfolinas/farmacologia , Fosfoproteínas/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Quinases S6 Ribossômicas/metabolismo , Células Tumorais Cultivadas , Tirosina/metabolismo
16.
Endocrinology ; 139(5): 2392-8, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9564850

RESUMO

The insulin receptor, following insulin stimulation of cells, triggers formation of various signaling complexes. In rat HTC hepatoma cells overexpressing normal human insulin receptors (HTC-IR), p85 regulatory subunit of phosphatidylinositol-3-kinase (PI3K) forms signaling complexes containing the insulin receptor, insulin receptor substrate 1 (IRS-1), guanosine triphosphatase-activating protein (GAP) and 60-70 kDa phosphotyrosine proteins (p60-70). In the present study, we demonstrate that p60-70 interacts directly with the p85 subunit via src homology 2 domain of the latter. Employing antibodies specific to two p85 isoforms, p85alpha and p85beta, we demonstrate that HTC-IR cells express both p85 isoforms, and these isoforms induce the formation of similar signaling complexes in response to insulin. p60-70, present in both alpha-p85alpha and alpha-p85beta immunoprecipitates, is a GAP-associated protein, but is distinct from the p68 src-associated protein in mitosis (Sam68) by several criteria. These data suggest that 1) GAP-associated protein, but not Sam68, is a part of insulin signaling complexes; and 2) p85alpha and p85beta form similar, but distinct, insulin receptor signaling complexes.


Assuntos
Insulina/metabolismo , Mitose , Proteínas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais , Proteínas Adaptadoras de Transdução de Sinal , Animais , Proteínas de Transporte/metabolismo , Proteínas de Ligação a DNA , Proteínas Ativadoras de GTPase , Humanos , Técnicas de Imunoadsorção , Neoplasias Hepáticas Experimentais , Proteínas Ligantes de Maltose , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Fosfotirosina/análise , Fosfotirosina/metabolismo , Ratos , Receptor de Insulina/metabolismo , Proteínas Recombinantes , Compostos de Sulfidrila/metabolismo , Células Tumorais Cultivadas
17.
J Cell Biochem ; 68(3): 366-77, 1998 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-9518262

RESUMO

An elevated content of membrane glycoprotein PC-1 has been observed in cells and tissues of insulin resistant patients. In addition, in vitro overexpression of PC-1 in cultured cells induces insulin resistance associated with diminished insulin receptor tyrosine kinase activity. We now find that PC-1 overexpression also influences insulin receptor signaling at a step downstream of insulin receptor tyrosine kinase, independent of insulin receptor tyrosine kinase. In the present studies, we employed Chinese hamster ovary cells that overexpress the human insulin receptor (CHO IR cells; approximately 10(6) receptors per cell), and transfected them with human PC-1 c-DNA (CHO IR PC-1). In CHO IR PC-1 cells, insulin receptor tyrosine kinase activity was unchanged, following insulin treatment of cells. However, several biological effects of insulin, including glucose and amino acid uptake, were decreased. In CHO IR PC-1 cells, insulin stimulation of mitogen-activated protein (MAP) kinase activity was normal, suggesting that PC-1 overexpression did not affect insulin receptor activation of Ras, which is upstream of MAP kinase. Also, insulin-stimulated phosphatidylinositol (PI)-3-kinase activity was normal, suggesting that PC-1 overexpression did not interfere with the activation of this enzyme by insulin receptor substrate-1. In these cells, however, insulin stimulation of p70 ribosomal S6 kinase activity was diminished. These studies suggest, therefore, that, in addition to blocking insulin receptor tyrosine kinase activation, PC-1 can also block insulin receptor signaling at a post-receptor site.


Assuntos
Insulina/fisiologia , Glicoproteínas de Membrana/fisiologia , Diester Fosfórico Hidrolases , Pirofosfatases , Receptor de Insulina/fisiologia , Animais , Células CHO , Cricetinae , Expressão Gênica/genética , Humanos , Glicoproteínas de Membrana/genética , Proteínas Tirosina Quinases/análise , Receptor de Insulina/análise , Receptor de Insulina/genética , Proteínas Recombinantes/genética , Transdução de Sinais/fisiologia
18.
J Recept Signal Transduct Res ; 18(4-6): 243-63, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9879060

RESUMO

In rat HTC hepatoma cells overexpressing human insulin receptors, insulin stimulated glycogen synthesis by 55-70%. To study postreceptor signaling events leading to insulin-stimulated glycogen synthesis in these cells, we have employed pathway-specific chemical inhibitors such as LY294002, rapamycin and PD98059 to inhibit phosphatidylinositol-3-kinase (PI3K), p70 ribosomal S6 kinase and mitogen-activated protein kinase (MAPK) kinase/MAPK, respectively. LY294002 (50 microM) completely abolished insulin-stimulated glycogen synthesis whereas rapamycin (2-20 nM) partially inhibited it. Neither LY294002 nor rapamycin significantly affected the basal glycogen synthesis. However, PD98059 (100 microM) significantly inhibited the basal glycogen synthesis without affecting insulin-stimulated glycogen synthesis. In these cells, insulin at 100 nM decreased glycogen synthase kinase 3 alpha (GSK3 alpha) activity by 30-35%. LY294002, but neither rapamycin nor PD98059, abolished insulin-induced inactivation of GSK3 alpha. These data suggest that insulin-stimulated glycogen synthesis in rat HTC hepatoma cells is mediated mainly by PI3K-dependent mechanism. In these cells, inactivation of GSK3 alpha, downstream of PI3K, may play a role in insulin-stimulated glycogen synthesis.


Assuntos
Carcinoma Hepatocelular/metabolismo , Glicogênio/biossíntese , Insulina/farmacologia , Neoplasias Hepáticas/metabolismo , Sequência de Aminoácidos , Animais , Proteínas Quinases Dependentes de Cálcio-Calmodulina/antagonistas & inibidores , Proteínas Quinases Dependentes de Cálcio-Calmodulina/fisiologia , Cromonas/farmacologia , Flavonoides/farmacologia , Quinase 3 da Glicogênio Sintase , Quinases da Glicogênio Sintase , Humanos , Dados de Sequência Molecular , Morfolinas/farmacologia , Fosfatidilinositol 3-Quinases/fisiologia , Fosforilação , Ratos , Sirolimo/farmacologia , Células Tumorais Cultivadas , Tirosina/metabolismo
19.
J Hepatobiliary Pancreat Surg ; 5(3): 303-8, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9880779

RESUMO

In the Far East, hepatic resection is the definitive treatment for complicated intrahepatic stones (IHS). However, many investigators have reported that the associated intrahepatic biliary stricture is the main cause of treatment failure. A retrospective comparative study was undertaken to clarify the long-term efficacy of hepatic resection for treatment of IHS and to investigate the clinical significance of intrahepatic biliary stricture in treatment failure after hepatic resection performed in 44 patients with symptomatic IHS. The patients were divided into two study groups: group A, with intrahepatic biliary stricture (n = 28) and group B, without stricture (n = 16). Residual or recurrent stones, recurrence of intrahepatic biliary stricture, late cholangitis, and final outcomes were analyzed and compared statistically between the two groups. The patients were followed up for a median duration of 65 months after hepatectomy. The overall incidence of residual or recurrent stones was 36% and 11%, respectively, in groups A and B. The initial treatment failure rate was 50% in group A and 31% in group B. Intrahepatic biliary stricture recurred in 46% of patients in group A, while none of the group B patients had biliary stricture recurrence (P = 0.001). More than two-thirds of the restrictures in group A were identified at the primary site. The incidence of late cholangitis was higher in group A (54%) than in group B (6%) (P = 0. 002). Three-quarters of the patients with cholangitis in group A had severe cholangitis, that was recurrent, and related to stones and strictures (n = 11). They and 2 asymptomatic patients in group B required secondary procedures done at a median of 12 months after hepatectomy. Final outcomes after hepatectomy with or without secondary management were good in 80%, fair in 16%, and poor in 4% of our 44 patients. Most recurrent cholangitis after hepatectomy in patients with IHS was related to recurrent intrahepatic ductal strictures. Therefore, to be effective, hepatic resection should include the strictured duct. However, with hepatectomy alone it is difficult to clear the IHS or relieve the ductal strictures completely, particularly in patients with bilateral IHS, so perioperative team approaches that include both radiologic and cholangioscopic interventions should be combined for the effective management of IHS.


Assuntos
Ductos Biliares Intra-Hepáticos , Colelitíase/cirurgia , Colestase Intra-Hepática/complicações , Hepatectomia , Estudos de Casos e Controles , Colangite/etiologia , Colangite/cirurgia , Colelitíase/complicações , Colestase Intra-Hepática/cirurgia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva , Estudos Retrospectivos , Fatores de Tempo , Falha de Tratamento
20.
Arch Pharm Res ; 21(2): 135-9, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9875420

RESUMO

High titer rabbit polyclonal antibodies (pAbs) which show a specificity for saikosaponin a (SSA), have been generated. The immunogen used was a conjugate of SSA linked through its glucose moiety to bovine serum albumin by periodate oxidation method. The antibody titers obtained from two rabbits, inoculated with the immunogen, reached a plateau after the fourth and third booster injection, respectively. The specificity of the pAbs was determined by hapten inhibition assays using several SSA-like structures. SSA competitively inhibited the binding of the rabbit anti-SSA pAbs to SSA-ovalbumin on solid phase, a coated antigen on the well. The antibodies showed high specificity to SSA, exhibiting no significant cross-reactivity with any of SSA analogues tested.


Assuntos
Imunossupressores/imunologia , Ácido Oleanólico/análogos & derivados , Plantas Medicinais/química , Sapogeninas/imunologia , Saponinas , Animais , Anticorpos/isolamento & purificação , Sequência de Carboidratos , Bovinos , Meios de Cultura , Haptenos/imunologia , Dados de Sequência Molecular , Soroalbumina Bovina
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