Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 62
Filtrar
1.
West Indian med. j ; 62(2): 140-144, Feb. 2013. ilus
Artigo em Inglês | LILACS | ID: biblio-1045606

RESUMO

The present study summarizes the current knowledge of the heat and cold stress which might significantly affect military activities and might also occur among travellers who are not well adapted to weather variations during their journey. The selection of the best clothing is a very important factor in preserving thermal comfort. Our experiences with thermal manikin are also represented in this paper.


El presente trabajo resume los conocimientos actuales sobre el calor y el estrés por frío, que puede afectar significativamente la preparación militar, y pueden también ocurrir entre viajeros no bien adaptados a los cambios de tiempo y temperatura durante su viaje. La selección de la ropa mejor y más adecuada es también un factor muy importante para evitar el calor y el estrés por frío, y mantener el confort térmico. Nuestras experiencias con maniquíes térmicos también aparecen en este documento.


Assuntos
Humanos , Roupa de Proteção , Transtornos de Estresse por Calor/prevenção & controle , Hipotermia/prevenção & controle , Manequins , Temperatura Baixa/efeitos adversos , Temperatura Alta/efeitos adversos , Hipotermia/etiologia
2.
West Indian Med J ; 62(2): 140-4, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24564064

RESUMO

The present study summarizes the current knowledge of the heat and cold stress which might significantly affect military activities and might also occur among travellers who are not well adapted to weather variations during their journey. The selection of the best clothing is a very important factor in preserving thermal comfort. Our experiences with thermal manikin are also represented in this paper.


Assuntos
Temperatura Baixa/efeitos adversos , Transtornos de Estresse por Calor/prevenção & controle , Temperatura Alta/efeitos adversos , Hipotermia/prevenção & controle , Manequins , Roupa de Proteção , Transtornos de Estresse por Calor/etiologia , Humanos , Hipotermia/etiologia
3.
Cell Mol Life Sci ; 61(12): 1485-97, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15197472

RESUMO

Cyclins are regulatory proteins that interact with cyclin-dependent kinases (CDKs) to control progression through the cell cycle. In Arabidopsis thaliana, 34 cyclin genes have been described, grouped into five different types (A, B, D, H, and T). A novel class of seven cyclins was isolated and characterized in Arabidopsis, designated P-type cyclins (CYCPs). They all share a conserved central region of 100 amino acids ("cyclin box") displaying homology to the corresponding region of the PHO80 cyclin from Saccharomyces cerevisiae and the related G1 cyclins from Trypanosoma cruzi and T. brucei. The CYCP4;2 gene was able to partially re-establish the phosphate-dependent expression of the PHO5 gene in a pho80 mutant strain of yeast. The CYCPs interact preferentially with CDKA;1 in vivo and in vitro as shown by yeast two-hybrid analysis and co-immunoprecipitation experiments. P-type cyclins were mostly expressed in proliferating cells, albeit also in differentiating and mature tissues. The possible role of CYCPs in linking cell division, cell differentiation, and the nutritional status of the cell is discussed.


Assuntos
Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Quinases Ciclina-Dependentes/química , Ciclinas/química , Ciclinas/genética , Regulação da Expressão Gênica de Plantas , Proteínas Repressoras/química , Proteínas Repressoras/genética , Proteínas de Saccharomyces cerevisiae/genética , Motivos de Aminoácidos , Sequência de Aminoácidos , Arabidopsis , Proteínas de Arabidopsis/metabolismo , Diferenciação Celular , Núcleo Celular/metabolismo , Quinases Ciclina-Dependentes/metabolismo , Citoplasma/metabolismo , Teste de Complementação Genética , Hibridização In Situ , Modelos Biológicos , Dados de Sequência Molecular , Mutação , Fosfatos/química , Filogenia , Plasmídeos/metabolismo , Testes de Precipitina , Ligação Proteica , Biossíntese de Proteínas , Estrutura Terciária de Proteína , RNA/química , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas de Saccharomyces cerevisiae/química , Homologia de Sequência de Aminoácidos , Transcrição Gênica , Técnicas do Sistema de Duplo-Híbrido
4.
Horm Metab Res ; 36(3): 155-63, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15057668

RESUMO

Free radicals are involved in several pathological processes in living organisms, for example in athero- and oncogenesis. Some steroids are known to be effective antioxidants, while others do not play any such role. The aim of our study was to examine the antioxidant capability of different metabolites in the synthesis of steroid hormones. As a model, we chose human neutrophils producing superoxide anion, which is the source of many other radicals. Neutrophils were separated from healthy volunteers. Isolated cells were incubated with varying concentrations of steroid compounds and stimulated with N-formyl-Met-Leu-Phe. Superoxide anion production was determined by photometry. Neutrophils incubated with corticosterone and 18-hydroxy-deoxycorticosterone showed a significant reduction in superoxide production, whereas we found a significant enhancement in the presence of 11beta-hydroxyprogesterone. Furthermore, we observed a non-significant decreasing trend after incubation with cholesterol 3-sulphate and an increasing tendency using 11-hydroxyandrostenedione. We were also able to produce newer morphological and functional evidence of the role of myeloperoxidase enzyme in the steroidal antioxidant effect by electronic microscopy and use of sodium hypochlorite in our incubation model. Based on these results, we conclude that not only steroid end products but also their intermediate metabolites, most of which are also present in human plasma, partly influence free radical metabolism. Thus, this study provides further argument for the search for the molecular basis responsible for the antioxidant effect of steroid structures. This may lead to new opportunities for finding really efficient antioxidants, which might perhaps be used in a combined manner with other agents in the fight against certain life-threatening diseases.


Assuntos
Desoxicorticosterona/análogos & derivados , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Pró-Fármacos/farmacologia , Esteroides/farmacologia , Superóxidos/metabolismo , Adulto , Idoso , Antioxidantes/farmacologia , Ésteres do Colesterol/farmacologia , Corticosterona/farmacologia , Desoxicorticosterona/farmacologia , Feminino , Humanos , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , N-Formilmetionina Leucil-Fenilalanina/farmacologia , Neutrófilos/enzimologia , Neutrófilos/ultraestrutura , Peroxidase/metabolismo , Superóxidos/antagonistas & inibidores
5.
Cell Mol Life Sci ; 60(2): 401-12, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12678503

RESUMO

Although the majority of cyclin-dependent kinases (CDKs) play a key role in cell cycle progression, recent evidence has shown that CDKs are also implicated in transcription regulation. Here, we describe two Arabidopsis CDKs designated Arath;CDKC;1 and Arath; CDKC;2. These CDKs share a PITAIRE signature in the cyclin-binding domain and the structural characteristics of mammalian CDK9. Yeast two-hybrid screens and immunoprecipitation assays identified CDKC-interacting proteins with homology to the animal cyclin T/cyclin K group. We suggest that these Arabidopsis CDKCs may be part of a kinase complex similar to the animal positive transcription elongation factor b, whose activity is essential for transcription control. Expression studies showed that Arath; CDKC transcripts are mainly confined to epidermal tissues and are most abundant in flower tissues. No expression was detected in actively dividing Arabidopsis tissues, suggesting a role for the CDKC proteins in differentiated cells.


Assuntos
Arabidopsis/metabolismo , Quinases Ciclina-Dependentes/química , Quinases Ciclina-Dependentes/metabolismo , Ciclinas/química , Ciclinas/metabolismo , Regulação da Expressão Gênica de Plantas , Motivos de Aminoácidos , Sequência de Aminoácidos , Arabidopsis/química , Divisão Celular , Evolução Molecular , Dados de Sequência Molecular , Estrutura Terciária de Proteína , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Homologia de Sequência de Aminoácidos
6.
Pharmazie ; 57(2): 142-6, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11878192

RESUMO

The aim of the present study was to evaluate the soft corticosteroid BNP-166 in rats and dogs treated orally with 0.2, 2.0, and 20.0 mg/kg for 28 days and the reversibility of any abnormalities during a 14-day post-dosing period. The test substance, BNP-166, was well tolerated during the 28-day treatment period. The observed changes were all characteristic for the pharmacological actions of a glucocorticoid. Treatment related changes occurred in the adrenals and thymus, and, to a lesser extent, in the lymph nodes, spleen and liver. There were no statistically significant reductions in the cortisol levels of all groups in the 0.2 and 2 mg/kg treatments. Significant reductions were observed in the high-dose group (20 mg/kg), but levels returned to normal by the end of the 14-day recovery period. Based on the results, the No Observable Adverse Effect Level (NOAEL) of BNP-166 soft corticosteroid in rat and dog after 28-day oral administration is 2 mg/kg. This value is approximately 40 times higher than that of budesonide. Pharmacodynamic and receptor binding studies have shown BNP-166 to have a similar potency to budesonide; therefore, BNP-166 can be considered safer when administered orally than other corticosteroids such as prednisolone or budesonide.


Assuntos
Corticosteroides/toxicidade , Glândulas Suprarrenais/patologia , Animais , Peso Corporal/efeitos dos fármacos , Cães , Feminino , Linfonodos/patologia , Masculino , Ratos , Especificidade da Espécie , Timo/patologia
7.
Exp Gerontol ; 37(1): 137-48, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11738154

RESUMO

Neutrophil granulocytes are involved in the pathogenesis of atherosclerosis also through their free radical generation. The aim of the study was to test how extracellular levels of myeloperoxidase (MPO; a granulocyte enzyme playing role in free radical production) change by age and what effect this change has on the production of the free radical superoxide anion by neutrophils. We also wanted to examine whether the antioxidant effect of different steroid hormones is realized through the MPO. Plasma myeloperoxidase concentrations of healthy blood donors were quantified by ELISA. Superoxide anion production was measured by photometry. Myeloperoxidase concentration was significantly lower in plasmas obtained from older women and men than in those from younger subjects. Adding the MPO inhibitors 4-aminobenzoic acid hydrazide (ABAH) and indomethacin to the granulocytes, the generation of superoxide anion increased and the decreasing effect of the steroids on superoxide production was inhibited. Incubating the neutrophils with the product of the reaction catalyzed by MPO itself (hypochlorite anion), we found significant decrease in superoxide generation. According to our results MPO seems to diminish the production of superoxide anion and so probably has an antioxidant ability. Therefore, its lower plasma levels may contribute to the increasing incidence of atherosclerosis and other free radical mediated disorders in old people. Thus, after further studies MPO might become one of the indicators of cardiovascular risk and the scavenger capacity in general.


Assuntos
Peroxidase/sangue , Pós-Menopausa/sangue , Pré-Menopausa/sangue , Superóxidos/metabolismo , Adulto , Idoso , Compostos de Anilina/farmacologia , Células Cultivadas , Inibidores Enzimáticos/farmacologia , Feminino , Humanos , Indometacina/farmacologia , Masculino , Pessoa de Meia-Idade , Neutrófilos/citologia , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Peroxidase/antagonistas & inibidores , Esteróis/farmacologia , Testosterona/farmacologia
8.
BJOG ; 108(5): 474-81, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11368132

RESUMO

OBJECTIVE: To test whether the menopause entails any changes in the myeloperoxidase activity of neutrophil granulocytes. The effects of hormone replacement therapy on myeloperoxidase activity and related changes in free radical production were also investigated. DESIGN: Laboratory investigation of the effect of oestrogen on intracellular myeloperoxidase activity and release from human neutrophil granulocytes. Analysis of related changes in superoxide anion generation. SETTING: 2nd Department of Medicine and 1st Department of Obstetrics and Gynaecology, Semmelweis University, Budapest. SAMPLES: Intracellular myeloperoxidase activity (mean peroxidase index) was measured automatically in blood samples obtained for general laboratory work-up from 135 randomly selected patients in our department. Blood samples from 11 postmenopausal women were analysed before and during hormone replacement therapy. Blood samples from 20 healthy volunteers were obtained and neutrophil granulocytes separated for in vitro measurement of superoxide anion production after adding myeloperoxidase to the incubation media. METHODS: The mean peroxidase index was measured using a Technicon H-3 instrument. myeloperoxidase release from neutrophils was quantified by ELISA technique. Superoxide production of isolated neutrophil granulocytes was measured by photometry. MAIN OUTCOME MEASURES: Intracellular activity of myeloperoxidase, concentration of myeloperoxidase-protein in supernatant of neutrophils, release of superoxide anion from neutrophil granulocytes. RESULTS: 1. Intracellular myeloperoxidase activity in neutrophils was lower in postmenopausal women, than in females with regular cycles (-1.84 +/- 3.06 versus 1.59 +/- 3.55, P < 0,001). 2. In postmenopausal women intracellular myeloperoxidase activity and myeloperoxidase release increased during hormone replacement therapy (-5.54 +/- 6.63 versus -0.2 +/- 6.05; P < 0.001 and 52.74 mU/ml +/- 25.73 versus 251.4 +/-234.1 mU/ml; P < 0.05). 3. Adding myeloperoxidase to neutrophil granulocyte suspensions, the production of superoxide anion fell (e.g. adding 280 ng/ml myeloperoxidase: 77.9 +/- 14.04 % of control production, P < 0.001). CONCLUSION: Hormone replacement restores the reduced myeloperoxidase activity in menopausal women. Adding myeloperoxidase to neutrophil granulocytes, the production of free radicals decreases.


Assuntos
Terapia de Reposição de Estrogênios , Estrogênios/farmacologia , Menopausa/metabolismo , Neutrófilos/enzimologia , Peroxidase/metabolismo , Superóxidos/antagonistas & inibidores , Adulto , Indução Enzimática , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Radicais Livres/metabolismo , Humanos , Técnicas In Vitro , Masculino , Pessoa de Meia-Idade , Peroxidase/sangue , Fotometria/métodos , Superóxidos/sangue
9.
J Exp Bot ; 52(355): 215-21, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11283165

RESUMO

A calmodulin like domain protein kinase (CPK) homologue was identified in alfalfa and termed MsCPK3. The full-length sequence of cDNA encoded a 535 amino acid polypeptide with a molecular weight of 60.2 kDa. The deduced amino acid sequence showed all the conserved motifs that define other members of this kinase family, such as serine-threonine kinase domain, a junction region and four potential Ca2+ -binding EF sites. The recombinant MsCPK3 protein purified from E. coli was activated by Ca2+ and inhibited by calmodulin antagonist (W-7) in in vitro phosphorylation assays. The expression of MsCPK3 gene increased in the early phase of the 2,4-D induced alfalfa somatic embryogenesis. Heat shock also activated this gene while kinetin, ABA and NaCl treatment did not result in MsCPK3 mRNA accumulation. The data presented suggest that the new alfalfa CPK differs in stress responses from the previously described homologues and in its potential involvement in hormone and stress-activated reprogramming of developmental pathways during somatic embryogenesis.


Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/genética , Medicago sativa/enzimologia , Ácido 2,4-Diclorofenoxiacético/farmacologia , Ácido Abscísico/farmacologia , Sequência de Aminoácidos , Células Cultivadas , Clonagem Molecular , DNA de Plantas , Quinase do Fator 2 de Elongação , Escherichia coli/genética , Genes de Plantas , Proteínas de Choque Térmico/metabolismo , Ácidos Indolacéticos/farmacologia , Medicago sativa/genética , Dados de Sequência Molecular , Fosforilação , Reguladores de Crescimento de Plantas/farmacologia , RNA de Plantas , Proteínas Recombinantes/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Transdução de Sinais
10.
FEBS Lett ; 486(1): 79-87, 2000 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-11108847

RESUMO

E2F/DP complexes play a pivotal role in the regulation of the G1/S transition in animals. Recently, plant E2F homologs have been cloned, but DP-related sequences have not been identified so far. Here we report that Arabidopsis thaliana contains at least two different DP-related genes, AtDPa and AtDPb. They exhibit an overall domain organization similar to that of their animal counterparts, although phylogenetic analysis demonstrated that they form a separate subgroup. AtDPs efficiently heterodimerize in vitro with the Arabidopsis E2F-related proteins, AtE2Fa and AtE2Fb through their dimerization domains. AtDPa and AtE2Fa are predominantly produced in actively dividing cells with highest transcript levels in early S phase cells.


Assuntos
Arabidopsis/genética , Proteínas de Transporte , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Genes de Plantas/genética , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos , Animais , Sítios de Ligação , Ciclo Celular , Dimerização , Fatores de Transcrição E2F , Regulação da Expressão Gênica de Plantas , Humanos , Dados de Sequência Molecular , Mutação/genética , Especificidade de Órgãos , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Testes de Precipitina , Ligação Proteica , Estrutura Terciária de Proteína , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Proteína 1 de Ligação ao Retinoblastoma , Alinhamento de Sequência , Fator de Transcrição DP1 , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo , Técnicas do Sistema de Duplo-Híbrido
11.
Plant Mol Biol ; 43(5-6): 595-605, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11089863

RESUMO

Reversible phosphorylation of proteins by kinases and phosphatases plays a key regulatory role in several eukaryotic cellular functions including the control of the division cycle. Increasing numbers of sequence and biochemical data show the involvement of cyclin-dependent kinases (CDKs) and cyclins in regulation of the cell cycle progression in higher plants. The complexity represented by different types of CDKs and cyclins in a single species such as alfalfa, indicates that multicomponent regulatory pathways control G2/M transition. A set of cdc2-related genes (cdc2Ms A, B, D and F) was expressed in G2 and M cells. Phosphorylation assays also revealed that at least three kinase complexes (Cdc2Ms A/B, D and F) were successively active in G2/M cells after synchronization. Interaction between alfalfa mitotic cyclin (Medsa;CycB2;1) and a kinase partner has been reported previously. The present yeast two-hybrid analyses showed differential interaction between defined D-type cyclins and Cdc2Ms kinases functioning in G2/M phases. Localization of Cdc2Ms F kinase to the preprophase band (PPB), the perinuclear ring in early prophase, the mitotic spindle and the phragmoplast indicated a pivotal role for this kinase in mitotic plant cells. So far limited research efforts have been devoted to the functions of phosphatases in the control of plant cell division. A homologue of dual phosphatase, cdc25, has not been cloned yet from alfalfa; however tyrosine phosphorylation was indicated in the case of Cdc2Ms A kinase and the p(13suc1)-bound kinase activity was increased by treatment of this complex with recombinant Drosophila Cdc25. The potential role of serine/threonine phosphatases can be concluded from inhibitor studies based on okadaic acid or endothall. Endothall elevated the kinase activity of p(13suc1)-bound fractions in G2-phase alfalfa cells. These biochemical data are in accordance with observed cytological abnormalities. The present overview with selected original data outlines a conclusion that emphasizes the complexity of G2/M regulatory events in flowering plants.


Assuntos
Quinases Ciclina-Dependentes/metabolismo , Fase G2/fisiologia , Medicago sativa/citologia , Mitose/fisiologia , Monoéster Fosfórico Hidrolases/metabolismo , Proteína Quinase CDC2/metabolismo , Ciclinas/metabolismo , Histonas/metabolismo , Medicago sativa/enzimologia , Medicago sativa/fisiologia , Fosfoproteínas Fosfatases/metabolismo , Fosforilação , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/fisiologia
12.
Menopause ; 7(1): 31-5, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10646701

RESUMO

BACKGROUND: The rate and severity of hypertension increase dramatically after menopause. Complications seem to be more frequent and marked in hypertensive patients with greater blood pressure (BP) variability, and antihypertensive treatment does not easily reduce this variability. The effect of hormone replacement therapy (HRT) on BP and its variability is not well understood in moderate to severe hypertension, but estrogen may have calcium channel-blocking properties. Cardiovascular events occur more frequently in the morning, likely in part because of a rise in BP. DESIGN: We prospectively studied 34 postmenopausal women with treated hypertension (mean age = 53 years) and receiving a cyclic combination of estradiol and norgestrel for 19 weeks with 24-h ambulatory BP monitoring. RESULTS: Mean daily BP and its variability decreased significantly with HRT (149.3 +/- 6.1 mm Hg vs. 140.3 +/- 8.5 mm Hg [p < 0.001]; diastolic: 95.4 +/- 4.7 mm Hg vs. 92.4 +/- 7.2 mm Hg [p < 0.05]). There was also a significant decrease in the early morning BP values after HRT (154.0 +/- 6.9 mm Hg vs. 145.6 +/- 11.0 mm Hg [p < 0.001]; diastolic: 98.0 +/- 4.8 mm Hg vs. 95.1 +/- 10.0 mm Hg [p < 0.05]). Subjects who were taking calcium channel blockers (n = 11) had only half the reduction in 24-h systolic BP compared with those who were not taking calcium channel blockers (5.3 mm Hg vs. 10.5 mm Hg), and the reduction in those who were taking calcium channel blockers failed to reach statistical significance. CONCLUSIONS: Our results demonstrate that HRT may have a role in decreasing the severity of hypertension, and the mechanism of its action might be through calcium channels.


Assuntos
Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Terapia de Reposição de Estrogênios , Hipertensão/tratamento farmacológico , Pós-Menopausa/fisiologia , Bloqueadores dos Canais de Cálcio/uso terapêutico , Estradiol/farmacologia , Feminino , Humanos , Hipertensão/fisiopatologia , Pessoa de Meia-Idade , Norgestrel/farmacologia , Congêneres da Progesterona/farmacologia , Estudos Prospectivos
13.
Orv Hetil ; 140(29): 1625-30, 1999 Jul 18.
Artigo em Húngaro | MEDLINE | ID: mdl-10443140

RESUMO

Free radicals which are produced constantly in the human body have a significant role in the development of atherosclerosis. The responsibility of leukocytes for vascular disease has been proved in several ways. Hormonally active women are protected much more against myocardial infarction than men, which fact can be explained partly by endocrinological reasons, too. The authors have set the aim to investigate whether estrogen therapy effects on the one hand the intracellular activity of the granulocyte-enzyme, myeloperoxidase (MPO), which takes place in free radical reactions and on the other hand the amount of MPO released from neutrophils. In the case of women having menopause and being treated with hormone replacement (n = 11) the intracellular activity and the amount of MPO-release increased significantly as compared to the level at the time of starting taking the medicine (p < 0.001). Based on the results it can be supposed that the vasoprotective effect of estrogens is fulfilled through their influence on the MPO enzyme, too. Besides the fact that intensified MPO activity through enhanced consumption might induce the decreased accumulation of H2O2 (a reactive oxygen species, substrate of MPO), MPO also has a role in the termination of the whole process of free radical production in granulocytes by the inactivation of the NADPH-oxidase system. This means that the growing intracellular MPO activity and the increased amount of enzyme released induce the decrease of the amount of free radicals produced during the "respiratory burst" and this is advantageous from the point of view of vasoprotection. The increased MPO activity and the NADPH-oxidase inactivation supposed to be elicited by it, might have further positive consequences since MPO has an effect on HDL-metabolism and the outflow of cholesterol from "foam cells", NADPH-oxidase has a suspected role in LDL-oxidation and NADPH is one of the cofactors of NO-synthase (NOS). The decreased superoxide anion level on the other hand may mitigate the chance of the neutralizing of nitric oxide (NO) by it. The superoxide anion is a potent vasoconstrictor and therefore, its diminished production may be beneficial, i.e. decreases the risk of coronary spasm. The new conceptual synthesis worked out by the authors may provide a possible explanation of the increased susceptibility to infections during steroid treatment, too.


Assuntos
Estrogênios/farmacologia , Granulócitos/efeitos dos fármacos , Ativação de Neutrófilo/efeitos dos fármacos , Neutrófilos/efeitos dos fármacos , Peroxidase/metabolismo , Terapia de Reposição de Estrogênios , Feminino , Radicais Livres/metabolismo , Humanos , Masculino
14.
Arch Biochem Biophys ; 360(2): 206-14, 1998 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-9851832

RESUMO

The catalytic subunit of protein phosphatase 1 (PP1c) was purified from an alfalfa (Medicago sativa) microcallus cell culture. The preparation was inhibited by rabbit muscle inhibitor-2 and okadaic acid and had a molecular mass of 35 kDa. Five distinct cDNAs termed MsPP1alpha, -beta, -gamma, -delta, and -epsilon were cloned from a M. sativa somatic embryo library. MsPP1alpha was identical to a cDNA reported earlier [A. Páy, M. Pirck, L. Bögre, H. Hirt, and E. Heberle-Bors Mol. Gen. Genet. 244, 176-182, 1994], while the others represented novel isoforms encoded by separate genes. The predicted amino acid sequences of MsPP1alpha, -beta, -gamma, -delta, and -epsilon were highly similar to each other and to other known PP1c sequences. The GST-MsPP1ss fusion protein expressed in Escherichia coli was catalytically active and was inhibited by inhibitor-2 and okadaic acid. Affinity-purified polyclonal MsPP1antipeptide antibody detected a protein of 36 kDa in crude cell extracts. These results proved that the cDNA clone encoded an active PP1c which was very similar to the purified enzyme. The mRNA and protein concentrations of PP1c as well as the specific activity of protein phosphatase 1 did not change during the cell cycle in a synchronized alfalfa cell culture. On the other hand, the isoforms exhibited different steady-state mRNA levels in different plant organs suggesting tissue-specific functions.


Assuntos
Domínio Catalítico , Clonagem Molecular , Isoenzimas/metabolismo , Medicago sativa/enzimologia , Fosfoproteínas Fosfatases/metabolismo , Sequência de Aminoácidos , Anticorpos , Afidicolina/farmacologia , Northern Blotting , Southern Blotting , Ciclo Celular/efeitos dos fármacos , Sequência Conservada , Escherichia coli , Expressão Gênica/efeitos dos fármacos , Biblioteca Gênica , Concentração Inibidora 50 , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/imunologia , Medicago sativa/genética , Dados de Sequência Molecular , Especificidade de Órgãos , Fosfoproteínas Fosfatases/antagonistas & inibidores , Fosfoproteínas Fosfatases/química , Fosfoproteínas Fosfatases/genética , Estruturas Vegetais/genética , Proteína Fosfatase 1 , Proteínas Recombinantes de Fusão/antagonistas & inibidores , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/metabolismo
15.
Plant Mol Biol ; 34(4): 593-602, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9247541

RESUMO

Differential screening of a cDNA library of 2,4-dichlorophenoxiacetic acid (2,4-D)-treated alfalfa (Medicago sativa) callus tissues resulted in the isolation of a 571 bp cDNA clone (MsPRP5) encoding for a proline-rich protein (84 amino acids) with a specific repeat unit of TPVLPPRK/RGRPPPVPP. In addition, a characteristic amino acid block (PPVYK) previously found in other proline-rich proteins also occurs in the C-terminal region of MsPRP5. At the N-terminal, a signal peptide similar to leader sequences of extracellular proteins can be predicted. According to the northern analysis, the corresponding gene is not expressed or is weakly expressed in differentiated vegetative organs and somatic embryos. However the accumulation of MsPRP5 mRNA is auxin concentration-dependent in dedifferentiated callus tissue. An increase in the amount of steady-state mRNA was detected already 20 min after auxin shock (100 microM 2,4-D). Maximum expression was observed at 24-48 h in the presence of 2,4-D. Elevated expression was also found in cells recovering after heat shock and wounding stress. In synchronized alfalfa cells, the transcript level of MsPRP5 gene fluctuated during cell cycle progression with peaks in G1/S phase cells. Considering the structural features and expression properties of MsPRP5, this clone may represents a new type of proline-rich protein gene which responds to hormonal shock and some other stresses as well.


Assuntos
Ácido 2,4-Diclorofenoxiacético/farmacologia , Regulação da Expressão Gênica de Plantas , Proteínas de Choque Térmico/genética , Ácidos Indolacéticos/farmacologia , Medicago sativa/genética , Proteínas de Plantas , Sequência de Aminoácidos , Sequência de Bases , Ciclo Celular/genética , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas/efeitos dos fármacos , DNA Complementar/genética , Dosagem de Genes , Biblioteca Gênica , Medicago sativa/citologia , Medicago sativa/efeitos dos fármacos , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Prolina , Conformação Proteica , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos
16.
Plant Cell ; 9(2): 223-35, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9061953

RESUMO

The eukaryotic cell division cycle is coordinated by cyclin-dependent kinases (CDKs), represented by a single major serine/threonine kinase in yeasts (Cdc2/CDC28) and a family of kinases (CDK1 to CDK8) in human cells. Previously, two cdc2 homologs, cdc2MsA and cdc2MsB, have been identified in alfalfa (Medicago sativa). By isolating cDNAs using a cdc2MsA probe, we demonstrate here that at least four additional cdc2 homologous genes are expressed in the tetraploid alfalfa. Proteins encoded by the new cdc2MsC to cdc2MsF cDNAs share the characteristic functional domains of CDKs with the conserved and plant-specific sequence elements. Transcripts from cdc2MsA, cdc2MsB, cdc2MsC, and cdc2MsE genes are synthesized throughout the cell cycle, whereas the amounts of cdc2MsD and cdc2MsF mRNAs peak during G2-to-M phases. The translation of Cdc2MsA/B, Cdc2MsD, and Cdc2MsF proteins follows the pattern of transcript accumulation. The multiplicity of kinase complexes with cell cycle phase-dependent activities was revealed by in vitro phosphorylation experiments. Proteins bound to p13suc1-Sepharose or immunoprecipitated with Cdc2MsA/B antibodies from cells at G1-to-S and G2-to-M phase boundaries showed elevated kinase activities. the Cdc2MsF antibodies separated a G2-to-M phase-related kinase complex. Detection of histone H1 phosphorylation activities in fractions immunoprecipitated with antimitotic cyclin (CyclinMs2) antibodies from G2-to-M phase cells indicates the complex formation between this cyclin and a kinase partner in alfalfa. The observed fluctuation of transcript levels, amounts, and activities of kinases in different cell cycle phases reflects a multilevel regulatory system during cell cycle progression in plants.


Assuntos
Quinases Ciclina-Dependentes/metabolismo , Medicago sativa/enzimologia , Sequência de Aminoácidos , Afidicolina/farmacologia , Ciclo Celular , Regulação Enzimológica da Expressão Gênica , Humanos , Medicago sativa/citologia , Dados de Sequência Molecular , Proteínas Quinases/metabolismo , RNA Mensageiro/metabolismo , Alinhamento de Sequência
17.
EMBO J ; 13(5): 1093-102, 1994 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-8131743

RESUMO

We have shown that treatment of Medicago microcallus suspensions with the cognate Rhizobium meliloti Nod signal molecule NodRm-IV(C16:2,S) can modify gene expression both qualitatively and quantitatively. At concentrations of 10(-6) - 10(-9) M, this host specific plant morphogen but not the inactive non-sulfated molecule stimulated cell cycle progression as indicated by the significantly enhanced thymidine incorporation, elevated number of S phase cells, increase in kinase activity of the p34cdc2-related complexes and enhancement of the level of expression of several cell cycle marker genes, the histone H3-1, the cdc2Ms and the cyclin cycMs2. The presented data suggest that at least part of the physiological role of the Nod factor may be linked to molecular events involved in the control of the plant cell division cycle. In situ hybridization experiments with antisense H3-1 RNA probe indicated that only certain cells of the calli were able to respond to the Nod factor. High (10(-6) M) but not low (10(-9) M) concentrations of the active Nod factors induced the expression of the isoflavone reductase gene (IFR), a marker gene of the isoflavonoid biosynthesis pathway in most callus cells. Our results indicate that Medicago cell responses to the Nod signal molecules can be investigated in suspension cultures.


Assuntos
Genes de Plantas , Isoflavonas/metabolismo , Proteínas de Membrana , Oxirredutases atuantes sobre Doadores de Grupo CH-CH , Células Vegetais , Proteínas de Plantas/biossíntese , Plantas/metabolismo , Sinorhizobium meliloti/fisiologia , Proteína Quinase CDC2/metabolismo , Ciclo Celular , Células Cultivadas , Ciclinas/biossíntese , Ciclinas/metabolismo , Marcadores Genéticos , Histonas/genética , Hibridização In Situ , Medicago sativa/genética , Oxirredutases/biossíntese , Oxirredutases/genética , Plantas/genética , Timidina/metabolismo
18.
Plant Mol Biol ; 16(6): 999-1007, 1991 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1863771

RESUMO

We have isolated two cDNA clones (Mshsp18-1; Mshsp18-2) from alfalfa (Medicago sativa L.) which encode for small heat shock proteins (HSPs) belonging to the hsp17 subfamily. The predicted amino acid sequences of the two alfalfa proteins are 92% identical and a similar degree of homology (90%) can be detected between Mshsp18-2 and the pea hsp17. In comparison to various members of small HSPs from soybean amino acid sequence similarities of 80-86% were identified. The alfalfa HSPs share a homologous stretch of amino acids in the carboxy terminal region with hsp22, 23, 26 from Drosophila. This region contains the GVLTV motif which is characteristic of several members of small HSPs. At room temperature alfalfa hsp18 mRNAs were not detectable in root and leaf tissues but northern analysis showed a low level of expression in microcallus suspension (MCS). The transcription of Mshsp18 genes is induced by elevated temperature, CdCl2 treatment and osmotic shock in cultured cells. In alfalfa somatic embryos derived from MCS a considerable amount of hsp18 mRNA can be detected during the early embryogenic stages under normal culture conditions. The differential expression of these genes during embryo development suggests a specific functional role for HSPs in plant cells at the time of the developmental switch in vitro.


Assuntos
Regulação da Expressão Gênica/fisiologia , Proteínas de Choque Térmico/genética , Medicago sativa/genética , Sequência de Aminoácidos , Sequência de Bases , Northern Blotting , Cádmio/farmacologia , Cloreto de Cádmio , Células Cultivadas , Temperatura Alta/efeitos adversos , Medicago sativa/efeitos dos fármacos , Medicago sativa/embriologia , Dados de Sequência Molecular , Família Multigênica/genética
19.
Eur J Haematol ; 43(1): 41-4, 1989 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2767241

RESUMO

The percentage of pitted erythrocytes and Howell-Jolly bodies in peripheral blood samples of 51 individuals following posttraumatic splenectomy and 20 patients splenectomized because of various haematological diseases differed significantly from each other (p less than 0.001) and from that of healthy controls (p less than 0.001). The percentage of pitted erythrocytes was significantly higher in pathologically shaped red blood cells (RBCs) (acanthocytes, schizocytes, elliptocytes) than in normal discoid shaped RBCs (p less than 0.001). As the number of pits per RBC showed great individual variations, a scoring system for the evaluation of pitted RBCs is proposed.


Assuntos
Eritrócitos Anormais/ultraestrutura , Eritrócitos/ultraestrutura , Doenças Hematológicas/cirurgia , Esplenectomia , Vacúolos/ultraestrutura , Ferimentos e Lesões/cirurgia , Adulto , Idoso , Inclusões Eritrocíticas/patologia , Feminino , Doenças Hematológicas/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Ferimentos e Lesões/sangue
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...