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1.
Health Promot Int ; 35(3): 470-477, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31071200

RESUMO

With the rise of digital technologies, electronic learning and communication tools are becoming a firm part of academia to promote knowledge of health sciences. This study sought to analyse the attitude of students regarding social media and digital learning for study purposes in sport and exercise science. A survey was carried out with a questionnaire (20 main items) in six sport science faculties, equally spread across Germany (G), Italy (I) and the United Kingdom (UK) between February and October 2017. The focus areas were students' usage of social media (Facebook, Google+, Instagram, LinkedIn, Skype, Twitter, WhatsApp, YouTube) for academic purposes and their use of e-learning. Data were analysed by quantitative and qualitative methods. 229 students participated in the study (G: 68, I: 121, UK: 40). While YouTube was mostly used for receiving knowledge, WhatsApp and Facebook showed additional preferences for peer contacts for learning purposes and knowledge discussions. Preferred online data sources were PubMed (77%), free access journals (67%), YouTube (66%) and Wikipedia (63%). Often used digital learning materials were own universities' PowerPoints (77%), scripts (59%) and scientific articles (53%). However, some preferences showed national differences. The evaluated participants showed an overall high use of social media and e-learning tools for their studies. Students would like more digital learning sources made available to them by their institutions. However, some differences in preferences of digital learning or communication tools may exist and this should be considered for international approaches to promote health knowledge among students.


Assuntos
Educação a Distância/métodos , Mídias Sociais , Estudantes , Bases de Dados Factuais , Europa (Continente) , Exercício Físico , Feminino , Humanos , Masculino , Medicina Esportiva/educação , Inquéritos e Questionários , Universidades , Adulto Jovem
2.
Osteoporos Int ; 27(3): 1239-1243, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26323330

RESUMO

SUMMARY: Rhythmic gymnastics as high-impact bone loading sport has positive effects on bone mineralization in prepubertal years. Sclerostin and preadipocyte factor-1 (Pref-1) are hormones that inhibit bone formation. The present study demonstrates that these hormones are higher in gymnasts, and gymnasts present higher bone mineral density (BMD) as compared to controls. INTRODUCTION: Rhythmic gymnasts (RG) start their heavy trainings already in prepuberty and despite of low body fat mass (FM) and hypoleptinemia, their BMD is higher than in non-trained normal girls. The specific role of sclerostin and Pref-1, which are the inhibitors of bone formation, in bone development is not well understood. The impact of sclerostin and Pref-1 levels on BMD, body composition, and adipocytokine values was studied in prepubertal RG and untrained controls (UC). METHODS: Sixty-four 9-10-year-old girls were divided into RG (n = 32) and UC (n = 32) groups. Bone mineral and body composition values were measured by dual-energy X-ray absorptiometry and bone age by X-ray. Sclerostin, Pref-1, leptin, and adiponectin levels were measured from fasting blood samples. RESULTS: Sclerostin (RG 19.8 ± 6.3 pmol/l; UC 15.8 ± 5.4 pmol/l) and Pref-1 (RG 1.6 ± 1.0 ng/ml; UC 1.1 ± 0.5 ng/ml) were higher (p < 0.05) in RG compared with UC. Sclerostin was related to adiponectin (r = 0.41; p < 0.05) in UC. No relationship was found between sclerostin and Pref-1 with BMD values in prepubertal RG and age-matched UC groups. CONCLUSIONS: Sclerostin and Pref-1 levels are higher in RG compared to UC girls. Specific physical activity pattern seen in prepubertal RG has a beneficial effect on bone mineralization despite increased levels of hormones that inhibit bone formation.


Assuntos
Composição Corporal/fisiologia , Densidade Óssea/fisiologia , Proteínas Morfogenéticas Ósseas/sangue , Ginástica/fisiologia , Peptídeos e Proteínas de Sinalização Intercelular/sangue , Proteínas de Membrana/sangue , Absorciometria de Fóton/métodos , Proteínas Adaptadoras de Transdução de Sinal , Adipocinas/sangue , Biomarcadores/sangue , Proteínas de Ligação ao Cálcio , Estudos de Casos e Controles , Criança , Feminino , Marcadores Genéticos , Humanos , Puberdade/sangue
3.
Biochem Biophys Res Commun ; 467(2): 348-53, 2015 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-26433123

RESUMO

Osteosarcoma (OS) is the most common primary malignant tumor of bone, occurring most frequently in children and adolescents. The mechanism of formation and development of OS have been studied for a long time. Tumor suppressor pathway governed by p53 gene are known to be involved in the pathogenesis of osteosarcoma. Moreover, loss of wild-type p53 activity is thought to be a major predictor of failure to respond to chemotherapy in various human cancers. In previous studies, we described the activity of a new indole derivative, NSC743420, belonging to the tubulin inhibitors family, capable to induce apoptosis and arrest of the cell cycle in the G2/M phase of various cancer cell lines. However, this molecule has never been tested on OS cell line. Here we address the activity of NSC743420 by examine whether differences in the p53 status could influence its effects on cell proliferation and death of OS cells. In particular, we compared the effect of the tested molecule on p53-wild type and p53-silenced U2OS cells, and on SaOS2 cell line, which is null for p53. Our results demonstrated that NSC743420 reduces OS cell proliferation by p53-dependent and p53-independent mechanisms. In particular, the molecule induces proliferative arrest that culminate to apoptosis in SaOS2 p53-null cells, while it brings a cytostatic and differentiating effect in U2OS cells, characterized by the cell cycle arrest in G0/G1 phase and increased alkaline phosphatase activity.


Assuntos
Antineoplásicos/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Indóis/farmacologia , Osteoblastos/efeitos dos fármacos , Tiazóis/farmacologia , Proteína Supressora de Tumor p53/genética , Fosfatase Alcalina/genética , Fosfatase Alcalina/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Expressão Gênica , Humanos , Osteoblastos/metabolismo , Osteoblastos/patologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Proteína Supressora de Tumor p53/antagonistas & inibidores , Proteína Supressora de Tumor p53/metabolismo
4.
J Anim Sci ; 92(12): 5593-602, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25367521

RESUMO

The aim of the present study was to evaluate in vitro the effect of some prebiotic substances and 2 dietary protein levels on the composition and activity of feline fecal microbiota. Two in vitro studies were conducted. First, 6 nondigestible oligosaccharides were studied; treatments were control diet (CTRL), gluconic acid (GA), carrot fiber (CF), fructooligosaccharides (FOS), galactooligosaccharides (GOS), lactitol (LAC), and pectins from citrus fruit (PEC). Substrates were added to feline fecal cultures at 2 g/L for 24 h incubation. Compared with the CTRL, ammonia had been reduced (P<0.05) by GOS (-9%) after 6 h and by GA (-14%), LAC (-12%), and PEC (-10%) after 24 h. After 24 h, all treatments had resulted in a lower pH versus the CTRL. Putrescine concentrations at 24 h were greater (P<0.05) in cultures treated with FOS (+90%), GOS (+96%), and LAC (+87%). Compared with the CTRL, total VFA were higher (P<0.05) in bottles containing CF (+41%), whereas the acetic to propionic acid ratio was reduced by LAC (-51%; P<0.05). After 24 h, Enterobacteriaceae had been reduced (P<0.05) by LAC and PEC. In a second study, LAC and FOS were selected to be tested in the presence of 2 diets differing in their protein content. There were 6 treatments: low-protein (LP) CTRL with no addition of prebiotics (CTRL-LP), high-protein (HP) CTRL with no addition of prebiotics (CTRL-HP), LP diet plus FOS, CTRL-HP plus FOS, LP diet plus LAC, and CTRL-HP plus LAC. Both FOS and LAC were added to feline fecal cultures at 2 g/L for 24 h incubation. Ammonia at 24 h was affected (P<0.05) by the protein level (36.2 vs. 50.2 mmol/L for LP and HP, respectively). The CTRL-HPs resulted in a higher pH and increased concentrations of biogenic amines were found after 6 and 24 h of incubation (P<0.05); putrescine at 24 h showed an increase (P<0.05) in cultures treated with FOS. Total VFA were influenced (P<0.05) by the protein level (40.9 vs. 32.6 mmol/L for LP and HP, respectively). At 24 h, the CTRL-HPs were associated with increased Clostridium perfringens and reduced Lactobacillus spp. and enterococci counts (P<0.05). The results from the present study show that different prebiotics exert different effects on the composition and activity of feline intestinal microbiota and that high dietary protein levels in a cat's diet can have negative effects on the animal intestinal environment.


Assuntos
Gatos/microbiologia , Proteínas Alimentares/farmacologia , Fezes/microbiologia , Intestinos/microbiologia , Microbiota/efeitos dos fármacos , Oligossacarídeos/farmacologia , Prebióticos/microbiologia , Análise de Variância , Animais , Cromatografia Gasosa/veterinária , Cromatografia Líquida de Alta Pressão/veterinária , Clostridium perfringens/efeitos dos fármacos , Proteínas Alimentares/administração & dosagem , Fluoresceína-5-Isotiocianato , Concentração de Íons de Hidrogênio , Hibridização in Situ Fluorescente/veterinária , Técnicas In Vitro/veterinária , Lactobacillus/efeitos dos fármacos , Microscopia de Fluorescência/veterinária , Oligossacarídeos/administração & dosagem
5.
Acta Paediatr ; 99(12): 1879-84, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20545933

RESUMO

AIM: To evaluate the relationships of visfatin, adiponectin and leptin with bone mineral density (BMD) and bone mineral content (BMC) in adolescent female athletes with different training patterns. METHODS: This study involved 170 healthy 13-15-year-old girls divided into six groups based on activity: sport games (i.e. basketball, volleyball, badminton) (n=49), track sprint (n=24), rhythmic gymnastics (n=23), swimming (n=24), cross-country skiing (n=17) and sedentary controls (n=33). BMD and BMC at femoral neck and lumbar spine (L2-L4) were measured using dual-energy X-ray absorptiometry. Visfatin, adiponectin, leptin, insulin and glucose were measured, and the insulin resistance index was calculated using homeostasis model assessment. RESULTS: There were no relationships found between visfatin concentrations and bone mineral parameters in adolescent female athletes or controls. Adiponectin was inversely correlated to BMD and BMC of femoral neck and lumbar spine (r=-0.47-0.62) in the swimmer group only, but after adjustments for age, height and body mass these associations disappeared. Leptin concentrations correlated with bone mineral parameters even after adjusting for age, height and body mass (r=0.42-0.63) in the gymnast group only. CONCLUSION: We may conclude that after adjustment, leptin is the only adipokine of those measured that correlates to femoral neck and lumbar spine BMD and femoral neck BMC in the rhythmic gymnast group.


Assuntos
Adiponectina/sangue , Densidade Óssea/fisiologia , Leptina/sangue , Nicotinamida Fosforribosiltransferase/sangue , Esportes/fisiologia , Adolescente , Atletas , Glicemia , Estudos de Casos e Controles , Estudos Transversais , Feminino , Colo do Fêmur/química , Humanos , Insulina/sangue , Resistência à Insulina , Vértebras Lombares/química , Educação Física e Treinamento
6.
Amino Acids ; 27(2): 207-14, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15378410

RESUMO

In a previous research, we have shown that adequate levels of polyamines are required in transformed mouse fibroblasts for the correlated activations of MAPK subtypes (ERK and JNK) and caspases induced by etoposide and leading to apoptosis. We report now that the treatment of fibroblasts with etoposide also elicited a progressive and sustained increase of NF-kappaB activation. The DNA binding activity of p65 NF-kappaB subunit was increased up to approximately 4-fold and was accompanied by enhancement of p65 phosphorylation. A two days pre-treatment of fibroblasts with alpha-difluoromethylornithine (DFMO), which caused polyamine depletion, provoked a slight activating effect when given alone, but markedly inhibited the etoposide-induced increases in p65 DNA binding and phosphorylation. The NF-kappaB inhibiting effect of DFMO was prevented by the addition of exogenous putrescine, which restored the intracellular content of polyamines. Selective inhibitors of the etoposide-stimulated MAPK subtypes also reduced NF-kappaB activation. Moreover, pharmacological NF-kappaB inhibition reduced the increase in caspase activity and cell death elicited by etoposide, suggesting that NF-kappaB is involved in signaling to apoptosis. The results of the present study, together with our previous findings, suggest that polyamines play a permissive role in the pathways triggered by etoposide and leading to cell death of fibroblasts, by supporting the activation of MAPKs, NF-kappaB and caspases.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Etoposídeo/farmacologia , Fibroblastos/metabolismo , NF-kappa B/metabolismo , Poliaminas/química , Animais , Apoptose , Western Blotting , Caspases/metabolismo , Linhagem Celular Transformada , Núcleo Celular/metabolismo , Cumarínicos/química , DNA/metabolismo , Eflornitina/química , Inibidores Enzimáticos/farmacologia , Etoposídeo/química , Flavonoides/farmacologia , Marcação In Situ das Extremidades Cortadas , Sistema de Sinalização das MAP Quinases , Camundongos , Fosforilação , Ligação Proteica , Fatores de Tempo
7.
Amino Acids ; 27(3-4): 359-65, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15452702

RESUMO

Polyamines are important multifunctional cellular components and are classically considered as mediators of cell growth and division. Recently polyamines have been also implicated in cell death. Now it appears that polyamines are bivalent regulators of cellular functions, promoting proliferation or cell death depending on the cell type and on environmental signals. This review draws a picture about the role of polyamines in signalling pathways related to apoptotic cell death and the proposed molecular targets of these polycations at the level of the apoptotic cascade. Solid evidence indicates that polyamines may affect the mitochondrial and postmitochondrial phases of apoptosis, by modulating cytochrome c release from mitochondria and activation of caspases. Recently, polyamines have been also implicated in the regulation of the premitochondrial phase of apoptosis, during which upstream apoptotic signal transduction pathways are activated. The studies reviewed here suggest that polyamines may participate in loops involving interaction with signal transduction pathways and activation/expression of proteins that may control cell death or cell growth.


Assuntos
Apoptose/fisiologia , Poliaminas/metabolismo , Transdução de Sinais , Animais , Ciclo Celular/fisiologia , Humanos , Mitocôndrias/metabolismo
8.
Dig Liver Dis ; 34(4): 279-84, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12038812

RESUMO

BACKGROUND: Oxidative stress in patients undergoing liver transplantation results both from the pre-existing cirrhosis and ischaemia-reperfusion injury related to surgery. Previous studies have provided information limited to the immediate post-operative period. It remains to be established whether this oxidative imbalance is reversed in a longer time. AIM, METHODS AND PATIENTS: This study aimed to compare plasma concentrations of thiobarbituric acid-reactant substances and alpha-tocopherol in 20 cirrhotic patients before liver transplantation and 22 patients in whom transplant had been carried out at least 6 months previously. Thirty healthy age and sex-matched volunteers served as controls (cross-sectional study). Five patients were evaluated before and after liver transplantation (longitudinal study). RESULTS AND CONCLUSIONS: Pre-transplant patients showed greater thiobarbituric acid-reactant substances and lower alpha-tocopherol levels than controls. Transplanted patients presented lower thiobarbituric acid-reactant substances and greater alpha-tocopherol levels than cirrhotic patients without reaching, however, the levels observed in controls. No correlations were found between oxidative parameters and liver tests. Hypertransaminasaemia, liver disease recurrence, and rejection episodes did not significantly influence the oxidative parameters. In the longitudinal study, transplantation induced a significant decrease in plasma thiobarbituric acid-reactant substances and a rise in alpha-tocopherol. Although a long-term improvement in the oxidative injury observed in cirrhotic patients occurs after liver transplantation, mild oxidative stress persists even in successfully transplanted patients.


Assuntos
Cirrose Hepática/fisiopatologia , Transplante de Fígado/fisiologia , Estresse Oxidativo , Adulto , Estudos Transversais , Feminino , Humanos , Peroxidação de Lipídeos , Cirrose Hepática/cirurgia , Masculino , Pessoa de Meia-Idade , Estresse Oxidativo/fisiologia , Período Pós-Operatório , Substâncias Reativas com Ácido Tiobarbitúrico/análise , alfa-Tocoferol/sangue
9.
Braz J Med Biol Res ; 35(4): 445-9, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11960193

RESUMO

Rotaviruses are the major cause of viral diarrhea in humans and animals. Actinomycin D (Act D) is an antibiotic that intercalates DNA and therefore inhibits DNA-dependent transcription. The current study was carried out to assess the influence of Act D on the replication of simian rotavirus (SA11) in cell culture. Virus-infected MA-104 cell cultures were studied in the presence of Act D at concentrations of 1.25 and 2.5 microg/ml. Treatment of rotavirus-infected cells with 2.5 microg/ml Act D 48 h post-infection reduced the cytoplasmic metachromasia after staining with acridine orange by 25%. Viral RNA labeled with 3H-uridine in the presence of the drug was separated by polyacrylamide gel electrophoresis. Viral RNA replication was not affected by Act D, but increased 3H-uridine uptake was demonstrable by infected cells in the presence of the drug. This possibly was due to the inhibition of cellular RNA synthesis by Act D, which thus enhances incorporation of the radionuclide into the viral RNA. Act D reduced the number of infected cells presenting virus-specific fluorescence 48 h post-infection by more than 50%. These data suggest that Act D may have complexed with viral RNA and prevented newly synthesized mRNA from being translated, but may not have prevented early replication.


Assuntos
Dactinomicina/farmacologia , Inibidores da Síntese de Ácido Nucleico/farmacologia , RNA Viral/efeitos dos fármacos , Rotavirus/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Animais , Técnicas de Cultura de Células , Macaca mulatta , Replicação Viral/fisiologia
10.
Braz. j. med. biol. res ; 35(4): 445-449, Apr. 2002. ilus, tab
Artigo em Inglês | LILACS | ID: lil-309197

RESUMO

Rotaviruses are the major cause of viral diarrhea in humans and animals. Actinomycin D (Act D) is an antibiotic that intercalates DNA and therefore inhibits DNA-dependent transcription. The current study was carried out to assess the influence of Act D on the replication of simian rotavirus (SA11) in cell culture. Virus-infected MA-104 cell cultures were studied in the presence of Act D at concentrations of 1.25 and 2.5 æg/ml. Treatment of rotavirus-infected cells with 2.5 æg/ml Act D 48 h post-infection reduced the cytoplasmic metachromasia after staining with acridine orange by 25 percent. Viral RNA labeled with ³H-uridine in the presence of the drug was separated by polyacrylamide gel electrophoresis. Viral RNA replication was not affected by Act D, but increased ³H-uridine uptake was demonstrable by infected cells in the presence of the drug. This possibly was due to the inhibition of cellular RNA synthesis by Act D, which thus enhances incorporation of the radionuclide into the viral RNA. Act D reduced the number of infected cells presenting virus-specific fluorescence 48 h post-infection by more than 50 percent. These data suggest that Act D may have complexed with viral RNA and prevented newly synthesized mRNA from being translated, but may not have prevented early replication


Assuntos
Animais , Dactinomicina , RNA Viral , Rotavirus , Replicação Viral , Técnicas de Cultura de Células , Macaca mulatta
11.
Biochem Pharmacol ; 62(3): 319-28, 2001 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-11434904

RESUMO

Intracellular signaling pathways involved in the survival of proliferating L1210 leukemia cells were investigated by using specific modulators. Among the various inhibitors tested, only 1H-[1,2,4]oxadiazole [4,3-a]quinoxalin-1-one (ODQ), a soluble guanylate cyclase (sGC) inhibitor, was found to induce a marked increase in caspase activity, which was associated with a loss of cell viability and a reduction in cGMP content. ODQ also provoked the processing of caspases-3 and -9, release of cytochrome c and, as early events, reduction of Bcl-2 content and dephosphorylation of Bad at Ser 112. Furthermore, YC-1, an sGC activator, and 8-Br-cGMP, a cell-permeant analogue of cGMP, exerted some protection against various apoptotic stimuli, such as serum deprivation or spermine accumulation. Although PD98059 (2'-amino-3'-methoxyflavone), an inhibitor of the p44/42 mitogen-activated protein kinase (MAPK) pathway, did not increase basal caspase activity, and ODQ did not affect p44/42 MAPK phosphorylation significantly, phorbol myristate acetate stimulated p44/42 MAPK and reduced caspase activation induced by ODQ, serum deprivation, and spermine in a p44/42-dependent manner. SB203580 (4-(4-fluorophenyl)-2-(4-methylsulfonylphenyl)-5-(4-pyridyl)1H-imidazole), a p38 MAPK inhibitor, also partially protected against ODQ-induced apoptosis by increasing p44/42 MAPK phosphorylation. In conclusion, these results suggest that sGC may be relevant both for survival of L1210 cells under basal growing conditions and for protection against various apoptotic stimuli. p44/42 MAPK activation may also confer some protection from apoptosis, but apparently through a pathway largely independent of cGMP.


Assuntos
Guanilato Ciclase/fisiologia , Leucemia L1210/patologia , Proteína Quinase 1 Ativada por Mitógeno/fisiologia , Proteínas Quinases Ativadas por Mitógeno/fisiologia , Animais , Apoptose , Caspases/metabolismo , Divisão Celular/efeitos dos fármacos , Divisão Celular/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , GMP Cíclico/metabolismo , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Guanilato Ciclase/antagonistas & inibidores , Imidazóis/farmacologia , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 3 Ativada por Mitógeno , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Oxidiazóis/farmacologia , Oxirredução , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Piridinas/farmacologia , Quinoxalinas/farmacologia , Transdução de Sinais , Células Tumorais Cultivadas
12.
Diabetes ; 50(7): 1580-7, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11423479

RESUMO

Acetyl-CoA carboxylase (ACC) catalyzes the formation of malonyl-CoA, a precursor in the biosynthesis of long-chain fatty acids, which have been implicated in physiological insulin secretion. The catalytic function of ACC is regulated by phosphorylation (inactive)-dephosphorylation (active). In this study we investigated whether similar regulatory mechanisms exist for ACC in the pancreatic islet beta-cell. ACC was quantitated in normal rat islets, human islets, and clonal beta-cells (HIT-15 or INS-1) using a [(14)C]bicarbonate fixation assay. In the beta-cell lysates, ACC was stimulated by magnesium in a concentration-dependent manner. Of all the dicarboxylic acids tested, only glutamate, albeit ineffective by itself, significantly potentiated magnesium-activated ACC in a concentration-dependent manner. ACC stimulation by glutamate and magnesium was maximally demonstrable in the cytosolic fraction; it was markedly reduced by okadaic acid (OKA) in concentrations (<50 nmol/l) that inhibited protein phosphatase 2A (PP2A). Furthermore, pretreatment of the cytosolic fraction with anti-PP2A serum attenuated the glutamate- and magnesium-mediated activation of ACC, thereby suggesting that ACC may be regulated by an OKA-sensitive PP2A-like enzyme. Streptavidin-agarose chromatography studies have indicated that glutamate- and magnesium-mediated effects on ACC are attributable to activation of ACC's dephosphorylation; this suggests that the stimulatory effects of glutamate and magnesium on ACC might involve activation of an OKA-sensitive PP2A-like enzyme that dephosphorylates and activates ACC. In our study, 5-amino-imidazolecarboxamide (AICA) riboside, a stimulator of AMP kinase, significantly inhibited glucose-mediated activation of ACC and insulin secretion from isolated beta-cells. Together, our data provide evidence for a unique regulatory mechanism for the activation of ACC in the pancreatic beta-cell, leading to the generation of physiological signals that may be relevant for physiological insulin secretion.


Assuntos
Acetil-CoA Carboxilase/metabolismo , Ácido Glutâmico/metabolismo , Ilhotas Pancreáticas/enzimologia , Magnésio/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Adenilato Quinase/metabolismo , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacologia , Animais , Células Cultivadas , Glucose/farmacologia , Humanos , Masculino , Proteína Fosfatase 2 , Ratos , Ribonucleosídeos/farmacologia
13.
Biochem J ; 355(Pt 1): 199-206, 2001 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-11256964

RESUMO

Activation of the caspase proteases represents a central point in apoptosis. The requirement for spermine for the processes leading to caspase activation has been studied in transformed embryonic fibroblasts obtained from gyro (Gy) mutant male mice. These cells lack spermine synthase activity and thus provide a valuable model to study the role of spermine in cell processes. Gy fibroblasts do not contain spermine and have a higher spermidine content. However, when compared with fibroblasts obtained from normal male littermates (N cells), Gy fibroblasts were observed to grow normally. The lack of spermine did not affect the expression of Bcl-2, and caspases 3 and 9 were activated by etoposide in both N and Gy cells, indicating that spermine is dispensable for caspase activation. Spermine deficiency did not significantly influence caspase activity in cells treated with etoposide, cycloheximide or staurosporine, but sensitized the cells to UV irradiation, which triggered significantly higher caspase activity in Gy cells compared with N cells. alpha-Difluoromethylornithine (DFMO), an inhibitor of polyamine synthesis that is able to deplete cells of putrescine and spermidine, but usually does not influence spermine content, was able to produce a more complete polyamine depletion in Gy cells. This depletion, which included spermine deficiency, dramatically increased caspase activation and cell death in Gy fibroblasts exposed to UV irradiation. On the other hand, in either N or Gy cells, DFMO treatment did not influence caspase activity triggered by staurosporine, but inhibited it when the inducers were cycloheximide or etoposide. In Gy cells depleted of polyamines by DFMO, polyamine replenishment with either spermidine or spermine was sufficient to restore caspase activity induced by etoposide, indicating that, in this model, polyamines have an interchangeable role in supporting caspase activation. Therefore, spermine is not required for such activation, and the effect and specificity of polyamine depletion on caspase activity may be very different, depending on the role of polyamines in the specific death pathways engaged by different stimuli. Some inducers of apoptosis, for example etoposide, absolutely require polyamines for caspase activation, yet the lack of polyamines, particularly spermine, strongly increases caspase activation when induced by UV irradiation.


Assuntos
Caspases/metabolismo , Poliaminas/metabolismo , Espermina Sintase/metabolismo , Animais , Western Blotting , Células Cultivadas , Cicloeximida/farmacologia , Eflornitina/farmacologia , Ativação Enzimática , Fibroblastos/efeitos dos fármacos , Fibroblastos/enzimologia , Fibroblastos/metabolismo , Masculino , Camundongos , Camundongos Mutantes , Inibidores da Síntese de Proteínas/farmacologia , Espermina Sintase/genética
14.
Pediatr Infect Dis J ; 20(1): 81-2, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11176575

RESUMO

It was previously reported from Italy that all patients with Kawasaki disease had a positive tuberculin intradermal test. In this study from Seattle, WA, nine patients with Kawasaki disease showed no reaction to intradermal tuberculin. The difference in results might be caused by the different tuberculin products.


Assuntos
Síndrome de Linfonodos Mucocutâneos/diagnóstico , Teste Tuberculínico , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Síndrome de Linfonodos Mucocutâneos/etiologia
15.
Cardiovasc Res ; 49(2): 408-16, 2001 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-11164851

RESUMO

OBJECTIVE: We have recently shown that tumor necrosis factor-alpha (TNFalpha) and lipopolysaccharide (LPS) stimulate DNA synthesis in chick embryo cardiomyocytes (CMs). The aim of the present research was to investigate the pathways involved in this mitogenic response. METHODS: CMs were isolated from 10-day-old chick embryos and grown to confluence. After 20 h of serum starvation the cells were treated with TNFalpha and LPS, and/or specific agonists and antagonists to manipulate the levels of polyamines, NO, cGMP and their biosynthetic enzymes ornithine decarboxylase (ODC), nitric oxide synthase (NOS) and soluble guanylate cyclase (sGC). ODC, NOS, sGC activities and cGMP contents were determined by radiochemical procedures. DNA synthesis was determined by incorporation of [3H]-thymidine. RESULTS: Treatment of CMs with TNFalpha and LPS increased cell number and [3H]-thymidine incorporation. Addition of TNFalpha and LPS provoked an induction of ODC, with consequent polyamine accumulation, and a more delayed enhancement of NOS activity, which appeared to be independent of the activation of the ODC-polyamine system. TNFalpha and LPS treatment also enhanced cGMP level in CMs and both polyamine and NO biosyntheses appeared to be required. Experiments with specific inhibitors of ODC and NOS, as well as with inhibitors of sGC and cGMP-dependent protein kinase (PKG), showed that polyamine-, NO- and cGMP-dependent pathways are required for the mitogenic action of TNFalpha and LPS. Moreover, addition of exogenous polyamines to untreated cells raised the cGMP level in a NO-dependent fashion, and enhanced [3H]-thymidine incorporation. The latter effect was inhibited by sGC or PKG inhibitors. Treatment of quiescent cells with NO donors, 8-bromo-cGMP or YC-1, an sGC activator, also promoted DNA synthesis. Furthermore, putrescine and NO donor can additively activate sGC in cell-free extracts. CONCLUSION: TNFalpha and LPS stimulate DNA synthesis in chick embryo CMs and this effect is mediated by polyamines, NO and intracellular cGMP.


Assuntos
Carbazóis , GMP Cíclico/metabolismo , DNA/biossíntese , Indóis , Miocárdio/metabolismo , Óxido Nítrico/metabolismo , Poliaminas/metabolismo , Alcaloides/farmacologia , Aminoquinolinas/farmacologia , Animais , Células Cultivadas , Embrião de Galinha , Eflornitina/farmacologia , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Guanilato Ciclase/antagonistas & inibidores , Guanilato Ciclase/metabolismo , Lipopolissacarídeos/farmacologia , Azul de Metileno/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Ornitina Descarboxilase/metabolismo , Inibidores da Ornitina Descarboxilase , Inibidores de Proteínas Quinases , Estimulação Química , Fator de Necrose Tumoral alfa/farmacologia , ômega-N-Metilarginina/farmacologia
16.
Biochem Pharmacol ; 61(1): 25-32, 2001 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-11137705

RESUMO

Treatment of serum-starved, human ECV304 cells with histamine or ATP elicited a transient induction of ornithine decarboxylase (ODC), a key enzyme in polyamine synthesis, to an extent similar to that provoked by phorbol myristate acetate or serum re-addition. All these agents also provoked an increase in active phosphorylated p44/42 mitogen-activated protein kinase (MAPK) and p38 MAPK. The involvement of p44/42 MAPK and p38 MAPK in the induction of ODC was investigated by using selective inhibitors. U0126 and PD98059, two specific p44/42 MAPK kinase inhibitors, prevented the induction of ODC elicited by any stimulus employed, whereas SB203580 and SB202190, which are widely used as p38 MAPK inhibitors, enhanced ODC induction in a way that appeared dependent on p44/42 MAPK activation. By using inhibitors of other key signaling proteins that may lead to activation of p44/42 MAPK, we provide evidence that protein kinase C, but not phosphoinositide 3-kinase, is involved in histamine-stimulated ODC induction. These results show that the p44/42 MAPK pathway, but not p38 MAPK, is essential for ODC induction stimulated either by agonists of G-protein-coupled receptors, phorbol esters, or serum, and suggest that the inhibition of ODC induction may be an important event in the antiproliferative response to p44/42 MAPK pathway inhibitors.


Assuntos
Inibidores Enzimáticos/farmacologia , Sistema de Sinalização das MAP Quinases , Proteína Quinase 1 Ativada por Mitógeno/fisiologia , Proteínas Quinases Ativadas por Mitógeno/fisiologia , Ornitina Descarboxilase/biossíntese , Trifosfato de Adenosina/farmacologia , Butadienos/farmacologia , Células Cultivadas , Meios de Cultura Livres de Soro , Ativação Enzimática , Indução Enzimática , Histamina/farmacologia , Humanos , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 3 Ativada por Mitógeno , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Nitrilas/farmacologia , Proteína Quinase C/fisiologia , Acetato de Tetradecanoilforbol/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno
17.
Biochem J ; 347 Pt 3: 875-80, 2000 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-10769194

RESUMO

Cytochrome c release from mitochondria to the cytosol represents a critical step in apoptosis, correlated to the activation of the caspase cascade. In this report, we show that addition of micromolar concentrations of polyamines to isolated rat heart mitochondria induces the release of cytochrome c. Spermine, which is effective at concentrations of 10-100 microM, is more potent than spermidine, whereas putrescine has no effect up to 1 mM. The release of cytochrome c caused by spermine is a rapid, saturable and selective process that is independent of mitochondria damage. Spermine, unlike polylysine, is able to release a discrete amount of cytochrome c from intact, functional mitochondria. The cytochrome c-releasing power of spermine is not affected by cyclosporin A, differently from the effect of permeability transition inducers. In a cardiac cell-free model of apoptosis, the latent caspase activity of cytosolic extracts from cardiomyocytes could be activated by cytochrome c released from spermine-treated heart mitochondria. These data indicate a novel mechanism of cytochrome c release from the mitochondrion, and suggest that prolonged and sustained elevation of polyamines, characteristic of some pathologies such as heart hypertrophy, could be involved in the development of apoptosis.


Assuntos
Grupo dos Citocromos c/metabolismo , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/metabolismo , Poliaminas/farmacologia , Animais , Apoptose , Caspases/metabolismo , Extratos Celulares , Embrião de Galinha , Ciclosporina/farmacologia , Citosol/efeitos dos fármacos , Citosol/enzimologia , Citosol/metabolismo , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Feminino , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/metabolismo , Cinética , Miocárdio/citologia , Permeabilidade/efeitos dos fármacos , Polilisina/farmacologia , Putrescina/farmacologia , Ratos , Ratos Wistar , Espermidina/farmacologia , Espermina/farmacologia
18.
Vet Microbiol ; 71(1-2): 1-8, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10665529

RESUMO

Rotaviruses are known as major causal agents of diarrhea in humans and animals. They affect young animals in intensive rearing and cause great economic losses. This study evaluated the infectivity of porcine rotavirus maintained for 32 months at approximately 10 degrees C in the original stool specimens. Thirty stool specimens of 1-4-week-old piglets from breeding farms located in the southwest of the State of Parana were selected for this study. They were randomly chosen from stool samples positive for rotavirus RNA by polyacrylamide gel electrophoresis (PAGE) at the time of collection. The thirty stool samples maintained for 32 months were re-tested by PAGE and 11 out of 30 were still positive showing physical integrity of the eleven segments of viral RNA. In order to demonstrate the maintenance of viral infectivity processed fecal homogenates were inoculated in MA-104 cell cultures. After an average of three blind passages 5 out of 11 samples demonstrated cytopathic effect similar to that of a simian rotavirus (SA-11) used as positive control. To confirm these findings an immunofluorescence test was performed and typical cytoplasmatic granular fluorescence was observed. Electron microscopy of stool samples showed that most of the virus particles were single-shelled and some were found to be in advanced state of degradation. The viral nucleic acid extracted from six fecal specimens out of those that showed physical integrity of rotavirus RNA by PAGE were also amplified when submitted to RT-PCR demonstrating stability of viral RNA. We therefore concluded that porcine rotavirus infectivity is maintained for a long period of time in stool specimens at low temperature.


Assuntos
Fezes/virologia , Infecções por Rotavirus/veterinária , Rotavirus/isolamento & purificação , Doenças dos Suínos/virologia , Animais , Eletroforese em Gel de Poliacrilamida/veterinária , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Microscopia Eletrônica/veterinária , RNA Viral/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Rotavirus/genética , Rotavirus/ultraestrutura , Infecções por Rotavirus/virologia , Suínos
19.
J Am Soc Echocardiogr ; 12(9): 769-72, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10477424

RESUMO

Anomalous origin of the left main coronary artery from the right sinus of Valsalva with retropulmonary course is a rare congenital abnormality. It is associated with a high incidence of sudden cardiac death, particularly among young, athletic individuals. Many of these individuals do not have symptoms before sudden death, and the diagnosis is usually made at postmortem examination. We present a case of a 15-year-old boy who was evaluated for a systolic click with routine 2-dimensional echocardiography. The anomalous coronary artery was serendipitously identified, allowing surgical intervention. Coronary artery origin and proximal course should be visualized on routine echocardiography in the pediatric population.


Assuntos
Anomalias dos Vasos Coronários/diagnóstico por imagem , Seio Aórtico/anormalidades , Adolescente , Aorta/diagnóstico por imagem , Humanos , Masculino , Artéria Pulmonar/diagnóstico por imagem , Ultrassonografia
20.
Biochim Biophys Acta ; 1450(3): 406-13, 1999 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-10395951

RESUMO

Caspase enzymes are a family of cysteine proteases that play a central role in apoptosis. Recently, it has been demonstrated that caspases can be S-nitrosylated and inhibited by nitric oxide (NO). The present report shows that in chick embryo heart cells (CEHC), NO donor molecules such as S-nitroso-N-acetylpenicillamine (SNAP), S-nitrosoglutathione, spermine-NO or sodium nitroprusside inhibit caspase activity in both basal and staurosporine-treated cells. However, the inhibitory effect of NO donors on caspase activity is accompanied by a parallel cytotoxic effect, that precludes NO to exert its antiapoptotic capability. N-Acetylcysteine (NAC) at a concentration of 10 mM blocks depletion of cellular glutathione and cell death in SNAP-treated CEHC, but it poorly affects the ability of SNAP to inhibit caspase activity. Consequently, in the presence of NAC, SNAP attenuates not only caspase activity but also cell death of staurosporine-treated CEHC. These data show that changes in the redox environment may inhibit NO-mediated toxicity, without affecting the antiapoptotic capability of NO, mediated by inhibition of caspase enzymes. NO may thus be transformed from a killer molecule into an antiapoptotic agent.


Assuntos
Apoptose/fisiologia , Inibidores de Caspase , Coração/fisiologia , Óxido Nítrico/fisiologia , Acetilcisteína/farmacologia , Animais , Apoptose/efeitos dos fármacos , Células Cultivadas , Embrião de Galinha , Glutationa/análogos & derivados , Glutationa/farmacologia , Coração/embriologia , Óxido Nítrico/antagonistas & inibidores , Nitrocompostos/farmacologia , Penicilamina/análogos & derivados , Penicilamina/farmacologia , Estaurosporina/farmacologia
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