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1.
Zh Nevrol Psikhiatr Im S S Korsakova ; 119(7. Vyp. 2): 25-32, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31532588

RESUMO

OBJECTIVE: To obtain further evidence of the efficacy of dormikind in infant/young children. MATERIAL AND METHODS: The study was performed in the group of 114 patients, aged 6 months to 2.5 years, with sleep and sleep initiation disorders. Sixty-four patients received treatment with dormikind (group 1) and 50 patients received behavioral therapy (group 2) for 28 days. RESULTS AND CONCLUSION: In group 1, sleep initiation decreased by 1.7 times and reached 26.2±4.8 minutes, the number of children sleeping on hands dropped by 8.7 times and sleeping in the parent's bed by 2 times. In group 2, the same characteristics changed by 1.1, 1.3 and 1.5 times, respectively, and sleep initiation reached 33.4±2.9 minutes. The number of patients of group 1 falling asleep in their own beds increased by 3.2 times vs 1.2 times in group 2. Duration of night sleep increased and frequency of awakening reduced as well. The significant positive dynamics was noted in the emotional-behavior state of children after therapy: the total score significantly improved by 2.9 times to the end of treatment compared to group 2 (by 1.3 times). IMOS score showed significant difference between the groups on «total recovery¼ and «significant improvement¼. Therefore, the high efficacy and safety of dormikind in children have been confirmed.


Assuntos
Distúrbios do Início e da Manutenção do Sono , Criança , Pré-Escolar , Humanos , Lactente , Pais , Sono , Distúrbios do Início e da Manutenção do Sono/diagnóstico , Distúrbios do Início e da Manutenção do Sono/terapia
2.
Ter Arkh ; 82(7): 34-40, 2010.
Artigo em Russo | MEDLINE | ID: mdl-20853607

RESUMO

AIM: To analyze the results of allogeneic and autologous hemopoietic cell transplantations (allo- and auto-HCT) in children with acute myeloid leukemia (AML) from an intermediate risk group, most of which were performed using lower-intensity conditioning modes. SUBJECTS AND METHODS. The study enrolled 36 children from an intermediate risk group, who had undergone auto-HCT (n = 22) or allo-HCT (n = 14) in December 1994 to December 2008. The patients' age was 0.7 to 16.6 years (median 12.8 years). Chemotherapeutic conditioning regimens were applied to all the patients. Melphalan was a basic myeloablative agent in 83.3% of cases. RESULTS: With a median follow-up of 4.6 years (1.1-13.8 years), three-year relapse-free survival (RFS) was 80.4%; overall survival (OS) was 65.6%. Recurrences were documented only in 6 (16.6%) patients from the auto-HCT. Transplantation-associated mortality (TAM) was 13.8% (five patients died). After allo-HCT versus auto-HCT, RFS, OS, and TAM were 100 and 68.7% (p = 0.03), 93.2 and 55.5% (p = 0.02), and 7.1 and 18.2%, respectively. Acute and chronic graft-versus-host reactions developed in 57.1 and 23.1%, respectively. CONCLUSION: Transplantation of allogeneic hemopoietic cells from a compatible related donor in the intermediate risk group children with AML, by using melphalan-based conditioning regimen, demonstrates a high survival rate with the minimum toxicity.


Assuntos
Transplante de Células-Tronco Hematopoéticas/métodos , Leucemia Mieloide Aguda/cirurgia , Condicionamento Pré-Transplante/métodos , Adolescente , Criança , Pré-Escolar , Intervalo Livre de Doença , Feminino , Sobrevivência de Enxerto , Reação Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas/mortalidade , Humanos , Lactente , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/mortalidade , Masculino , Recidiva , Indução de Remissão , Risco , Transplante Autólogo , Transplante Homólogo
3.
Ter Arkh ; 82(7): 41-7, 2010.
Artigo em Russo | MEDLINE | ID: mdl-20853608

RESUMO

AIM: To analyze the efficiency of transplantation of the bone marrow from a HLA-compatible unrelated donor and continued immunosuppressive therapy (IST) in children with aplastic anemia (AA) unresponsive to 2 courses of IST. SUBJECTS AND METHODS: The study enrolled 14 children aged 2-16 years (median 9 years). A control group comprised 26 patients in whom IST was continued. The median interval between the diagnosis of AA and transplantation was 26 months (9-156 months). The conditioning regimen consisted of thoracoabdominal irradiation in a dose of 2 Gy, fludarabin (Flu) 100-150 mg/m2, cyclophosphamide (Cy) 100-200 mg/kg, antithymocyte globulin (ATG) in 11 patients and Flu, Cy, and ATG in 3. A graft-versus-host reaction was prevented with mycophenolate mefetil in all the patients, tacrolimus in 11, and cyclosporin A in 3. Donors were compatible for high-resolution typing of 10/10 and 9/10 alleles in 8 and 6 patients, respectively; the source of a transplant was bone marrow in 13 patients and granulocyte colony-stimulating factor-mobilized peripheral blood precursors in one case. RESULTS: Thirteen patients achieved primary engraftment after single transplantation; one patient did after repeat transplantation. Grades I to II graft-versus-host reaction (GVHR) developed in 9 patients; postengraftment life-threatening infections in 3, extensive chronic GVHR in 2, circumscribed GVHR in 7. All fourteen hemopoietic cell transplant recipients followed for a median 17.5 months (range 1-71 months) were survivors. CONCLUSION: The likelihood of good survival after unrelated transplantations in AA is much higher than that after continued IST: 100% versus 15 +/- 11%.


Assuntos
Anemia Aplástica/cirurgia , Soro Antilinfocitário/uso terapêutico , Transplante de Medula Óssea/métodos , Ciclosporina/uso terapêutico , Antígenos HLA , Imunossupressores/uso terapêutico , Doadores de Tecidos , Condicionamento Pré-Transplante/métodos , Adolescente , Anemia Aplástica/tratamento farmacológico , Anemia Aplástica/etiologia , Anemia Aplástica/imunologia , Anemia Aplástica/radioterapia , Soro Antilinfocitário/administração & dosagem , Criança , Pré-Escolar , Terapia Combinada , Ciclosporina/administração & dosagem , Intervalo Livre de Doença , Sobrevivência de Enxerto , Reação Enxerto-Hospedeiro/imunologia , Antígenos HLA/genética , Humanos , Imunossupressores/administração & dosagem , Falha de Tratamento
4.
Ter Arkh ; 79(7): 57-61, 2007.
Artigo em Russo | MEDLINE | ID: mdl-17802792

RESUMO

AIM: To study clinical and laboratory characteristics of hepatitides and evaluate efficacy of immunosuppressive therapy and transplantation of the bone marrow in hepatitis-associated aplastic anemia (HAAA). MATERIAL AND METHODS: A retrospective analysis of case histories of children with HAAA was made. For all the patients standard tests for detection of aquired aplastic anemia and hepatitis were conducted. Transplantation of hemopoietic stem cells (THSC) from HLA-identical donors was made in 4 patients, 25 patients were treated with combined immunosuppressive therapy (antithymocytic globulin--ATG plus cyclosporin A -CsA), one patients received monotherapy with CsA, two--prednisolone and a short course of CsA, one child was untreated. RESULTS: Of 260 children admitted to hospital from April 1989 to July 2005 for aquired aplastic anemia, 33 (12.7%) met diagnostic criteria of HAAA. Boys to girls ratio was 267. Hepatitides were severe: median of alaninaminotransferase concentration was 1215 IU/l, aspartataminotransferase--789 IU/l, bilirubin--152.5 mcmol/l. Median of the interval from hepatitis symptoms to documentation of pancytopenia was 66 days (0-204 days). All four patients after THSC are alive for 30-72 months. Probability of complete remission after the first course of ATG+CsA is 0.72 +/- 0.09, probability of survival 0.81 +/- 0.07, median of the interval to transfusion independence--50 days. CONCLUSION: HAAA prognosis is good only in administration of up-to-date therapy. After seronegative hepatitis it is necessary to control hemogram parameters and in the presence of minimal cytopenia patients should be directed to hematological hospital.


Assuntos
Anemia Aplástica/diagnóstico , Anemia Aplástica/terapia , Transplante de Células-Tronco Hematopoéticas , Hepatite/complicações , Terapia de Imunossupressão , Adolescente , Alanina Transaminase/sangue , Anemia Aplástica/etiologia , Aspartato Aminotransferases/sangue , Bilirrubina/sangue , Criança , Pré-Escolar , Feminino , Humanos , Imunossupressores/uso terapêutico , Lactente , Masculino , Prognóstico , Estudos Retrospectivos , Resultado do Tratamento
5.
Artigo em Russo | MEDLINE | ID: mdl-12872625

RESUMO

Leukocyte elastase (LE) activity and autoantibodies to nerve growth factor (NGF) level as indexes of innate and adaptive immunity have been studied in children with psychomotor development disturbances of cerebral organic origin. LE activity was elevated in mild and moderate degrees of psychomotor disturbances caused by perinatal encephalopathy. In psychomotor disturbances of cerebral organic origin, higher LE activity was accompanied by a significant increase of autoantibodies to NGF titers. Correlations between immunological parameters and some clinical symptoms were found. The results obtained suggest involvement of innate and adaptive immune system links in pathophysiology of psychomotor development disturbances in children.


Assuntos
Autoanticorpos/sangue , Elastase de Leucócito/sangue , Transtornos Psicomotores/imunologia , Humanos , Imunidade , Lactente , Fator de Crescimento Neural/imunologia
6.
Ter Arkh ; 74(12): 71-7, 2002.
Artigo em Russo | MEDLINE | ID: mdl-12577848

RESUMO

AIM: To examine the pattern of changes in the count of peripheral granulocytes in children with aplastic anemias (AA), receiving a combined immunosuppressive therapy with antithymocytic globulin (ATG) and cyclosporin A in combination with granulocytic colony-stimulating factor (G-CSF). MATERIALS AND METHODS: 31 children (17 boys and 14 girls) aged 2-15 years (median 9 years) with newly diagnosed severe and very severe acquired AA took a combined immunosuppressive therapy with ATG and cyclosporin A in combination with G-CSF in an initial dose of 10 micrograms/kg a day. RESULTS: A three-linear and response was recorded in 19 (61%) children, an isolated granulocytic response was in 26 (84%). The interval median before the recovery of granulocytes to 1.5 x 10(9)/l and 5 x 10(9)/l was 19 and 38 days, respectively. CONCLUSION: Use of G-CSF may increase the count of granulocytes in the vast majority of patients with AA, without dramatic influence on the frequency of a three-linear response. Intermittent use of G-CSF may maintain the count of granulocytes long at the safe level and reduce the cost of treatment.


Assuntos
Anemia Aplástica/sangue , Anemia Aplástica/tratamento farmacológico , Soro Antilinfocitário/uso terapêutico , Ciclosporina/uso terapêutico , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Granulócitos , Imunossupressores/uso terapêutico , Contagem de Leucócitos , Adolescente , Soro Antilinfocitário/administração & dosagem , Criança , Pré-Escolar , Ciclosporina/administração & dosagem , Interpretação Estatística de Dados , Quimioterapia Combinada , Feminino , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Humanos , Imunossupressores/administração & dosagem , Masculino , Software , Fatores de Tempo
7.
Biochim Biophys Acta ; 1054(2): 237-45, 1990 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-2169312

RESUMO

The subcellular distribution of GTP binding proteins in human neutrophils and their functional coupling to the N-formylmethionylleucylphenylalanine (FMLP) receptor was characterized to provide insight into mechanisms of cellular activation. Human neutrophils were nitrogen cavitated and fractionated on discontinuous Percoll gradients. Four subcellular fractions were obtained: cytosol, light membranes enriched for plasma membranes, specific granules and azurophilic granules. ADP-ribosylation catalyzed by pertussis toxin (PT) revealed a major substrate of 40 kDa only in plasma membrane and cytosol, and antiserum specific for Gi alpha confirmed the presence of neutrophil Gi alpha in plasma membrane and cytosol and its absence from specific granules. The cytosolic PT substrate was shown to be mostly in monomeric form by molecular sieve chromatography. The rate of the ribosyltransferase reaction was several-fold lower in cytosol compared to plasma membranes, and the extent of ADP-ribosylation was greatly augmented by supplementation with beta gamma subunits in cytosol. ADP-ribosylation catalyzed by cholera toxin (CT) revealed substrates of 52, 43 and 40 kDa in plasma membrane alone. FMLP receptors in plasma membrane were shown to be coupled to the 40 kDa substrate for CT by ligand-modulation of ADP-ribosylation, while FMLP added to specific granules did not induce ribosylation of this substrate even though FMLP receptors were found in high density in this compartment. Both 24 and 26 kDa [32P]GTP binding proteins were found to codistribute with FMLP receptors in specific granules and plasma membranes. Functional evidence for the coupling of GTP binding proteins to the FMLP receptor in specific granules was obtained by modulating [3H]FMLP binding with GTP gamma S, and by accelerating [35S]GTP gamma S binding with FMLP.


Assuntos
Proteínas de Ligação ao GTP/metabolismo , Neutrófilos/metabolismo , Receptores Imunológicos/metabolismo , Membrana Celular/enzimologia , Toxina da Cólera/metabolismo , Citosol/enzimologia , Humanos , Ativação Linfocitária , Toxina Pertussis , Poli(ADP-Ribose) Polimerases/metabolismo , Povidona , Receptores de Formil Peptídeo , Sistemas do Segundo Mensageiro , Dióxido de Silício , Fatores de Virulência de Bordetella/metabolismo
8.
J Immunol ; 145(6): 1845-50, 1990 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-2118155

RESUMO

Neutrophils contain several distinct classes of secretory granules that may sequentially fuse with the phagosome after the ingestion of particulates, or that may be differentially exocytosed after cellular activation with soluble stimuli. The exocytosis of neutrophil secretory granules has been shown to be GTP-dependent at a step distal to activation of the transductional G proteins. Inasmuch as ras-related low molecular mass GTP-binding proteins have been shown to play regulatory roles in vesicle sorting in the secretory pathway in yeast, the differential mobilization of neutrophil granules might be regulated by distinct GTP-binding proteins. We therefore explored the distribution and identity of low molecular mass GTP-binding proteins in neutrophil secretory granules and other subcellular fractions. After lysis by nitrogen cavitation, four highly resolved fractions were harvested from discontinuous Percoll gradients: a microsomal fraction enriched for plasma membranes, specific granules, primary granules, and cytosol. At least seven bands of distinct Mr were detected by probing protein blots with [32P]GTP. Microsomes contained a prominent GTP-binding band at 26 kDa and weaker ones at 24 and 22.5 kDa; specific granules contained bands at 26, 24, 22, and 20 kDa; primary granules showed bands at 24 and 23 kDa; cytosol showed strong bands at 23.5 and 19 kDa and a weak band at 26 kDa. Antiserum against ADP-ribosylation factor reacted strongly with the 19-kDa band in cytosol but with none of the membrane fractions. None of these proteins was recognized by antibodies against ras or against Sec4p. Botulinum exoenzyme C3 labeled bands of molecular mass 20 and 21 kDa in cytosol and microsomes that have distinct mobilities from all the blotted [32P]GTP-binding proteins. The highly compartmentalized subcellular distribution of the blotted [32P]GTP-binding proteins in neutrophils is consistent with a regulatory role in the differential mobilization of granule compartments during cellular activation.


Assuntos
Grânulos Citoplasmáticos/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Neutrófilos/ultraestrutura , Adenosina Difosfato Ribose/metabolismo , Western Blotting , Compartimento Celular , Guanosina Trifosfato/metabolismo , Humanos , Técnicas Imunológicas , Técnicas In Vitro , Membranas Intracelulares/metabolismo , Microssomos/metabolismo , Peso Molecular , Neutrófilos/metabolismo , Frações Subcelulares/metabolismo
9.
Biochem Biophys Res Commun ; 149(3): 975-81, 1987 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-3122750

RESUMO

We report a 39 kDa substrate for cholera and pertussis toxins is present in D. discoideum membranes. This protein did not co-migrate with alpha subunits of either Gs (45 kDa and 52 kDa) or Gi (41 kDa) from control mammalian cells. The presence of GTP or its non-hydrolyzable analogs enhanced the ADP-ribosylation in response to cholera toxin, but did not significantly alter ADP-ribosylation by pertussis toxin. Divalent cations inhibited the ADP-ribosylation by both toxins. The possible association of this novel G-protein with D. discoideum adenylate cyclase may underlie some of the unique regulatory features of this enzyme. Alternatively, this G-protein may regulate one of several other cellular responses mediated by the cAMP receptor.


Assuntos
Adenosina Difosfato Ribose/biossíntese , Toxina Adenilato Ciclase , Membrana Celular/metabolismo , Toxina da Cólera/farmacologia , Dictyostelium/efeitos dos fármacos , Proteínas Fúngicas/metabolismo , Proteínas de Membrana/metabolismo , Toxina Pertussis , Fatores de Virulência de Bordetella/farmacologia , Toxina da Cólera/metabolismo , Proteínas de Ligação ao GTP , Guanosina Trifosfato/análogos & derivados , Guanosina Trifosfato/metabolismo , Fatores de Virulência de Bordetella/metabolismo
10.
J Biol Chem ; 262(17): 8071-6, 1987 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-3110144

RESUMO

(NH4)2SO4 was found to activate adenylate cyclase in Dictyostelium discoideum membranes. The effect of (NH4)2SO4 on the enzyme was observed after pretreatment of membranes but could not be observed if the salt was added to the assay mixture. Activation was seen when membranes were pretreated with 0.16 M (NH4)2SO4 and was maximal at 0.6-1.0 M. The maximal activation of the enzyme was observed within 3 min of pretreatment and was not readily reversible. The effect was specific for the NH+4 ion since pretreatment of membranes with other NH+4 salts could activate the enzyme, whereas pretreatment with NaCl or KCl could not. Pretreatment of plasma membranes with (NH4)2SO4 eliminated the sensitivity of the enzyme to the inhibitory effect of guanine nucleotides. (NH4)2SO4 pretreatment also significantly attenuated the inhibition by guanine nucleotides of cAMP binding to its plasma membrane receptor. The effect of (NH4)2SO4 on GTP inhibition of cAMP binding to its receptor was even more dramatic when the salt was present in the binding assay. (NH4)2SO4 also increased the ADP-ribosylation by cholera toxin of a 39,000-Da membrane protein. The data support the hypothesis that (NH4)2SO4-induced changes in adenylate cyclase and the cAMP receptor are due to an alteration of a putative G protein.


Assuntos
Adenilil Ciclases/metabolismo , Sulfato de Amônio/farmacologia , Dictyostelium/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Receptores Imunológicos/metabolismo , Amônia/farmacologia , Membrana Celular/metabolismo , Dictyostelium/efeitos dos fármacos , Nucleotídeos de Guanina/farmacologia , Cinética , Receptores de AMP Cíclico/efeitos dos fármacos , Receptores de AMP Cíclico/metabolismo , Receptores de Formil Peptídeo , Receptores Imunológicos/efeitos dos fármacos
11.
Biull Eksp Biol Med ; 103(5): 625-7, 1987 May.
Artigo em Russo | MEDLINE | ID: mdl-3593940

RESUMO

A noninvasive method of quantitative assessment of cerebral blood flow based on heat clearance from brain tissues is described. The rate of heat clearance depends essentially on the blood flow. The employment of microwave techniques permits to warm the investigated brain zone and to record the temperature decrease extracranially. As a thermometer, a microwave radiometer was used. The experiments were carried out on cats. The method was tested by current vasoactive drugs.


Assuntos
Circulação Cerebrovascular , Micro-Ondas , Animais , Regulação da Temperatura Corporal , Encéfalo/fisiologia , Gatos , Desenho de Equipamento , Métodos , Condutividade Térmica , Termômetros
12.
Biochim Biophys Acta ; 927(2): 235-46, 1987 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-2880607

RESUMO

Adenylate cyclase is the critical enzyme in the chemotactic signal relay mechanism of the slime mold amoeba, Dictyostelium discoideum. However, few studies examining the regulation of this enzyme have been performed in vitro due to the instability of enzyme activity in crude lysates. For studies presented in this communication, a membrane preparation has been isolated that exhibits a high specific activity adenylate cyclase that is stable during storage at -70 degrees C and under assay conditions at 27 degrees C. The enzyme was activated by micromolar concentrations of MnCl2. GTP and its non-hydrolyzable analog, guanosine 5'-(beta, gamma-imino)triphosphate, inhibited the enzyme non-competitively in the presence of either Mg2+ or Mn2+. However, this inhibition was more pronounced in the presence of Mn2+. Since guanylate cyclase activity in the D. discoideum membranes was less than 10% of the adenylate cyclase activity, there could not be a significant contribution by guanylate cyclase toward the production of cyclic AMP. Experiments indicate that D. discoideum adenylate cyclase was also regulated by adenosine analogs. The enzyme was inhibited by 2',5'-dideoxyadenosine and 2'-deoxyadenosine and inhibition was augmented by the presence of Mn2+. However, the inhibition was not entirely consistent with that which would be expected for the P-site of eukaryotic systems because some purine-modified adenosine analogs also inhibited the enzyme. Guanine nucleotides had no effect on the inhibition by either purine-modified or ribose-modified adenosine analogs. The binding of cyclic AMP to its receptor on the D. discoideum membranes was not affected by either MnCl2 or adenosine analogs.


Assuntos
Adenosina/farmacologia , Adenilil Ciclases/metabolismo , Cloretos , Dictyostelium/enzimologia , Proteínas Fúngicas/metabolismo , Compostos de Manganês , Manganês/farmacologia , Adenosina/análogos & derivados , Regulação Alostérica , AMP Cíclico/biossíntese , Guanosina Trifosfato/farmacologia , Guanilato Ciclase/metabolismo , Magnésio/farmacologia , Cloreto de Magnésio , Proteínas de Membrana/metabolismo , Temperatura
13.
Mol Pharmacol ; 29(3): 307-13, 1986 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2869405

RESUMO

The cellular mechanism of action of the cannabimimetic drugs is examined using cultured cells. In membranes from N18TG2 neuroblastoma cells and the neuroblastoma X glioma hybrid cells, NG108-15, the psychoactive cannabinoid drugs and their nantradol analogs could inhibit adenylate cyclase activity. This response was not observed in either the soluble adenylate cyclase from rat sperm or membrane-bound adenylate cyclases from C6 glioma or S49 lymphoma cells. This cellular selectivity provides further evidence for the existence of specific receptors for the cannabimimetic compounds. Receptor-mediated inhibition of adenylate cyclase requires the presence of a guanine nucleotide-binding protein complex, Gi. Gi can be functionally inactivated as a result of an ADP-ribosylation modification catalyzed by pertussis toxin. The present study demonstrates that pertussis toxin treatment of cells abolished the cannabimimetic response in intact cells and in membranes derived therefrom. The action of pertussis toxin required NAD+ as substrate for in vitro modification of neuroblastoma membranes. Furthermore, pertussis toxin was able to catalyze the labeling of a neuroblastoma membrane protein in vitro using [32P] NAD+ under conditions similar to those by which attenuation of the cannabimimetic inhibition of adenylate cyclase could be demonstrated. This evidence demonstrates the requirement for a functional Gi in the action of cannabimimetic drugs.


Assuntos
Inibidores de Adenilil Ciclases , Canabinoides/farmacologia , Proteínas de Ligação ao GTP/fisiologia , Adenosina Difosfato Ribose/metabolismo , Toxina Adenilato Ciclase , Animais , Carbacol/farmacologia , Células Cultivadas , AMP Cíclico/metabolismo , Dronabinol/farmacologia , Glioma/enzimologia , Células Híbridas , Linfoma/enzimologia , Manganês/farmacologia , Proteínas de Membrana/metabolismo , Morfina/farmacologia , NAD/metabolismo , Neuroblastoma/enzimologia , Toxina Pertussis , Ratos , Secretina/farmacologia , Somatostatina/farmacologia , Fatores de Virulência de Bordetella/farmacologia
14.
Artigo em Inglês | MEDLINE | ID: mdl-3998231

RESUMO

The regulation of adenylate cyclase by guanine nucleotides was examined in a plasma membrane preparation from Dictyostelium discoideum. At concentrations of greater than 10 microM, GDP, GTP and a non-hydrolyzable GTP analogue, guanosine 5'-(beta-gamma-imino)triphosphate (Gpp(NH)p), inhibited the enzyme. Guanosine, GMP and ITP were ineffective. The inhibition was not affected by variations in assay conditions (membrane concentration, time or temperature), the presence of cAMP, NaF or forskolin in the reaction mix, or variations in the stage of Dictyostelium discoideum development. There was no stimulation of adenylate cyclase by GTP or Gpp(NH)p under any conditions. Inhibition of adenylate cyclase by Gpp(NH)p was sensitive to divalent cations. The addition of MnCl2 resulted in increased adenylate cyclase activity, but augmented the inhibitory response to Gpp(NH)p. The differences between Dictyostelium discoideum and eukaryotic regulation of adenylate cyclase by guanine nucleotides are discussed.


Assuntos
Inibidores de Adenilil Ciclases , Dictyostelium/enzimologia , Nucleotídeos de Guanina/farmacologia , Membrana Celular/efeitos dos fármacos , Membrana Celular/enzimologia , Dictyostelium/efeitos dos fármacos
17.
Biokhimiia ; 46(8): 1411-9, 1981 Aug.
Artigo em Russo | MEDLINE | ID: mdl-7272361

RESUMO

The effects of 17 ATP analogs on the solubilized rabbit heart adenylate cyclase were studied. The triphosphate chain, position 8 of the adenine base and the ribose residue of the ATP molecule were modified. Despite the presence of the alkylating groups in two former types of the analogs tested, no covalent blocking of the active site of the enzyme was observed. Most of the compounds appeared to be competitive reversible inhibitors. The kinetic data confirmed the importance of the triphosphate chain for substrate binding in the active site of adenylate cyclase. (Formula: See Text) The inhibitors with different substituents in position 8 of the adenine base had a low affinity for the enzyme. The possible orientation of the triphosphate chain and the advantages of anti-conformation of the ATP molecule for their binding in the active site of adenylate cyclase are discussed.


Assuntos
Trifosfato de Adenosina/análogos & derivados , Adenilil Ciclases/metabolismo , Miocárdio/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Sítios de Ligação , Cinética , Ligação Proteica , Coelhos , Relação Estrutura-Atividade
18.
Neurochem Res ; 5(10): 1069-76, 1980 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7464978

RESUMO

The effect of the modification of synaptosomal membrane glycoproteins on the activity of adenylate cyclase was studied. It was found that the binding of concanavalin A to unmodified guinea pig cerebral cortex synaptosomal membrane did not change adenylate cyclase activity. Concanavalin A binding to synaptosomal membrane of hypoxic brain cortex resulted in no decrease of enzyme activity. The level of protein-bound sialic acid in these synaptosomal fractions was 20% lower than in the control. Treatment of synaptosomal membranes with neuraminidase resulted in a decrease of sialic acid content by about 70%, but it had no significant effect on adenylate cyclase activity. The modification with concanavalin A of sugar end groups exposed by neuraminidase treatment resulted in significant decrease of both basal and fluoride-stimulated adenylate cyclase activity. These results seem to indicate that some component of the adenylate cyclase complex of brain synaptosomal membranes is closely interacting with a carbohydrate-containing macromolecule on the cell surface.


Assuntos
Adenilil Ciclases/metabolismo , Glicoproteínas/fisiologia , Proteínas de Membrana/fisiologia , Sinaptossomos/metabolismo , Animais , Membrana Celular/metabolismo , Córtex Cerebral/metabolismo , Concanavalina A/farmacologia , Cobaias , Neuraminidase/farmacologia , Receptores de Concanavalina A/metabolismo , Ácidos Siálicos/análise
19.
Biokhimiia ; 43(1): 150-5, 1978 Jan.
Artigo em Russo | MEDLINE | ID: mdl-203340

RESUMO

Interaction of several nucleotide derivates with homogenous catalytic subunit of cyclo-AMP-dependent histone kinase from pig brain is studied. Inhibition constants of these compounds are calculated, and the affinity of inhibitors to the enzyme active site is evaluated. The nature of heterocyclic base is found to be the main contribution into binding with substrate. The enzyme specificity with respect to a number of bivalent metal ions is studied, and Mg2+ is demonstrated to be the only efficient enzyme activator. It is shown by means of stationary kinetics that histone kinase-catalysed phosphotransferase reaction has a "ping-pong"-like mechanism.


Assuntos
Encéfalo/enzimologia , Protamina Quinase/metabolismo , Proteínas Quinases/metabolismo , Animais , Sítios de Ligação , AMP Cíclico/farmacologia , Ativação Enzimática , Magnésio/farmacologia , Protamina Quinase/antagonistas & inibidores , Especificidade por Substrato , Suínos
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