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1.
Cell Death Dis ; 4: e886, 2013 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-24157880

RESUMO

HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome represents a life-threatening pregnancy disorder with high fetal and maternal mortality, but its underlying molecular mechanisms remain unknown. Although apoptosis has been implicated in HELLP syndrome, its pathogenic role remains largely unclear. In the present study, we investigated whether the detection of apoptosis by novel plasma biomarkers is of diagnostic value in HELLP patients. For this purpose, we analyzed two biomarkers that specifically detect apoptosis or overall cell death of epithelial cells, such as hepatocytes or placental trophoblasts, through the release of caspase-cleaved or total (caspase-cleaved and uncleaved) cytokeratin-18 (CK-18) in plasma of HELLP patients compared with pregnant as well as non-pregnant healthy women. In addition, caspase activation and cell death were determined in placental tissues of HELLP patients and individuals with normal pregnancy. In contrast to pregnant or non-pregnant healthy controls, we observed significantly increased levels of both caspase-cleaved and total CK-18 in plasma of HELLP patients. Following delivery, CK-18 levels rapidly decreased in HELLP patients. Caspase activation and cell death were also elevated in placental tissues from HELLP patients compared with healthy pregnant women. These data demonstrate not only that apoptosis is increased in HELLP syndrome, but also that caspase-cleaved or total CK-18 are promising plasma biomarkers to identify patients with HELLP syndrome. Thus, further studies are warranted to evaluate the utility of these biomarkers for monitoring disease activity in HELLP syndrome.


Assuntos
Síndrome HELLP/sangue , Síndrome HELLP/patologia , Queratina-18/sangue , Adulto , Alanina Transaminase/metabolismo , Aspartato Aminotransferases/metabolismo , Biomarcadores/sangue , Caspase 3/metabolismo , Morte Celular , Parto Obstétrico , Ativação Enzimática , Feminino , Síndrome HELLP/diagnóstico , Síndrome HELLP/enzimologia , Humanos , L-Lactato Desidrogenase/metabolismo , Placenta/enzimologia , Placenta/patologia , Gravidez , Análise de Regressão
2.
In Vivo ; 26(1): 31-8, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22210713

RESUMO

BACKGROUND/AIM: Administration of stem cells is a promising novel approach for treatment of neurodegenerative diseases. For in vivo monitoring of transplanted cells, non-invasive imaging modalities are needed. In this study we determined the tracking efficiency of a superparamagnetic iron oxide (SPIO)-labelled canine cell line (MTH53A) in vitro as well as the human CD34(+) umbilical cord blood stem cells (hUCBCs) in vitro and in vivo efficiency by magnetic resonance imaging (MRI). MATERIALS AND METHODS: SPIO-labelled MTH53A cells and hUCBCs were scanned in agar gel phantoms at 1.0 T or 7.0 T. For in vivo detection, 100,000 labelled hUCBCs were injected into the spinal cord of a transgenic amyotrophic lateral sclerosis (ALS) mouse and scanned at 7.0 T. RESULTS: In vitro, 100,000 MTH53A cells and 250,000 hUCBCs were visible at 1.0 T. Scanning with 7.0 T revealed 25,000 detectable MTH53A cells. In vivo, 7.0 T MRI showed clear signals of 100,000 implanted cells. CONCLUSION: MRI combined with SPIO nanoparticles provides valuable potential for non-invasive, non-toxic in vivo tracking of cells implanted into the spinal cord.


Assuntos
Esclerose Lateral Amiotrófica/diagnóstico por imagem , Esclerose Lateral Amiotrófica/cirurgia , Transplante de Células-Tronco de Sangue do Cordão Umbilical/métodos , Imageamento por Ressonância Magnética/métodos , Esclerose Lateral Amiotrófica/genética , Animais , Antígenos CD34/metabolismo , Contagem de Células , Linhagem Celular , Movimento Celular , Meios de Contraste , Modelos Animais de Doenças , Compostos Férricos , Sangue Fetal/citologia , Sangue Fetal/metabolismo , Humanos , Imageamento por Ressonância Magnética/instrumentação , Nanopartículas de Magnetita , Camundongos , Camundongos Transgênicos , Mutação , Imagens de Fantasmas , Radiografia , Superóxido Dismutase/genética , Fatores de Tempo
4.
Arq. bras. med. vet. zootec ; 61(3): 752-754, jun. 2009. tab
Artigo em Inglês | LILACS | ID: lil-519472

RESUMO

A ocorrência da infecção por coronavírus felino (FCoV), herpesvírus felino tipo 1 (FHV-1), calicivírus felino (FCV) e parvovírus felino (FPV) foi investigada mediante a detecção de anticorpos no soro de 97 gatos domésticos de Pelotas, RS, pelo teste de soro-neutralização. Entre os animais estudados, 51 não eram vacinados, 11 haviam sido vacinados contra FHV-1, FCV e FPV com pelo menos uma dose, e 35 tinham histórico de vacinação desconhecido. Foram detectados anticorpos para o FCoV em 75,2% (73/97) dos gatos. Anticorpos contra o FHV-1 estavam presentes em 38,1% (37/97): 73% (8/11) dos gatos vacinados, 39,2% (20/51) dos não vacinados e 25,7% (9/35) dos gatos com histórico de vacinação desconhecido. Anticorpos para o FCV estavam presentes em 56,7% (55/97): 81,8% (9/11) dos gatos vacinados, 52,9% (27/51) dos não vacinados, e 54,3% (19/35) dos gatos com histórico de vacinação desconhecido. Para o FPV, havia anticorpos em 69,1% (67/97): 100% (11/11) dos vacinados, 66,6% (34/51) dos não vacinados e 62,8% (22/35) dos gatos com histórico de vacinação desconhecido. Os resultados sugerem alta exposição ao FCoV, FHV-1, FCV e FPV na população de gatos na área estudada.


Assuntos
Animais , Masculino , Feminino , Anticorpos Antivirais/isolamento & purificação , Anticorpos Antivirais/sangue , Calicivirus Felino/imunologia , Coronavirus Felino/imunologia , Gatos/imunologia , Herpesviridae/imunologia , Parvovirus/imunologia
5.
Arq. bras. med. vet. zootec ; 60(1): 270-274, fev. 2008. tab
Artigo em Português | LILACS | ID: lil-483288

RESUMO

Antibody titres to canine distemper virus (CDV) and canine parvovirus (CPV) were measured in 132 dogs: 80 had been vaccinated at least once, 22 had not been vaccinated, and 30 had unknown vaccination history. Serum antibody titers were measured by means of serum neutralization (CDV) or hemagglutination inhibition (CPV). Serum CDV titers >20 and serum CPV titers >80 were considered protective. Protective antibodies to CDV were present in 40.1 percent of the population: 39.8 percent of the vaccinated dogs, 31.8 percent unvaccinated, and in 46.6 percent of the dogs with unknown vaccination history. Protective antibodies to CPV were present in 90.9 percent of the dogs: 93.7 percent of the vaccinated dogs, 90.9 percent of the unvaccinated, and 83.3 percent of the dogs with unknown vaccination history.


Assuntos
Animais , Anticorpos , Vírus da Cinomose Canina , Cães , Indicadores e Reagentes , Parvovirus Canino
6.
Arch Sex Behav ; 36(5): 702-16, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17333321

RESUMO

For a romantic attraction to be considered a mate poach, the pursuer must be aware that, while attempting to attract the targeted individual, the target is already in a nominally exclusive relationship. We investigated a methodological alternative for investigating the frequency of mate poaching. We presented university students with a survey informed by a definition of poaching that, in contrast to that which informed previous surveys, explicitly stated that the poacher must be aware while pursuing the targeted individual that the target was already in an exclusive relationship. Relative to participants in previous research, the current participants reported fewer experiences with poaching. We concluded that the current survey reduced the likelihood of participants reporting experiences with non-poaching forms of romantic attraction as experiences with poaching, and thereby provided more accurate estimates of the frequency of poaching. We also investigated the frequency of a previously uninvestigated form and temporal context of poaching and used a more fine-grained measure of the frequency of poaching than used in previous research. Discussion addresses limitations of the current research and suggests future directions for addressing them.


Assuntos
Corte/psicologia , Relações Interpessoais , Comportamento Sexual/psicologia , Percepção Social , Adulto , Relações Extramatrimoniais , Feminino , Humanos , Masculino , Motivação , Estudantes/psicologia , Inquéritos e Questionários
7.
Fetal Diagn Ther ; 21(6): 501-5, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16969003

RESUMO

BACKGROUND: Isolated fetal ascites can be caused by many heterogeneous disorders and is associated with a variety of conditions. Cloacal anomalies are rare abnormalities with a highly variable array of sonographic symptoms, which make them difficult to diagnose antenatally. We present a case with isolated fetal ascites without hydronephrosis caused by a cloacal malformation. CASE: A 28-year-old woman, gravida 2, para 1, was referred to our unit at 18 weeks gestation with a hyperdense structure in the fetal liver. Cordocentesis revealed a normal karyotype and negative viral titers. Isolated fetal ascites occurred for the first time at 23 weeks gestation. Serial ultrasounds showed progressive fetal ascites with no hydronephrosis at any time and no other malformations apart from the previously diagnosed hyperechogenic liver structure. After the insertion of an abdomino-amniotic shunt, a temporary reduction of the sonographically detectable ascites could be achieved. Cesarean delivery was necessary due to a pathological CTG at 33 weeks of gestation. The baby was born with a markedly distended abdomen. Postnatal radiologic examination showed two fistulae between the cloaca and the notedly dilated vagina and the rectum respectively. At the age of 3 months a vaginoplasty was performed, which involved creating a correctly positioned vaginal opening, reconstruction of the urethra and rectum as well as occlusion of the two fistulae. CONCLUSION: In view of the examinations, performed before and after delivery, it has to be assumed that fetal urine drained via the cloaca through the fallopian tubes into the abdomen. In contrast to usual appearance of cloacal malformations no hydronephrosis was detected and the kidney function was normal at all times. To our knowledge, this is the first published case of isolated fetal ascites without hydronephrosis caused by a cloacal malformation.


Assuntos
Ascite/diagnóstico por imagem , Cloaca/anormalidades , Doenças Fetais/diagnóstico por imagem , Adulto , Ascite/etiologia , Feminino , Humanos , Gravidez , Ultrassonografia
8.
Lik Sprava ; (3): 61-3, 2005.
Artigo em Ucraniano | MEDLINE | ID: mdl-16025681

RESUMO

Quantitative determination method of urea in blood serum and urine by means of ultraviolet spectroscopy is worked out. This method is based on direct determination of optical density of solutions of indicated biological fluids at three different waves of max. Absorption region of urea (275-300 nm). Morton-Shtab method was used to determine the concentration of urea. The method sensitivity is 1-20 Mg/cm3, the precision - 1.3-2.8%.


Assuntos
Ácido Úrico , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrofotometria Ultravioleta , Ácido Úrico/análise , Ácido Úrico/sangue , Ácido Úrico/urina
9.
Placenta ; 24(10): 979-84, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14580381

RESUMO

Analysis of the amount of oxidatively damaged proteins in placenta proteins from normal pregnancies and pre-eclampsia revealed a relative increase of about 30 per cent of damaged proteins in pre-eclamptic placenta. Previous work has demonstrated that these cell- and tissue-damaging oxidatively stressed proteins are metabolized particularly by the 20S proteasome. Evaluation of the proteasomal activity revealed a significantly reduced proteasome function in pre-eclamptic placenta by about 30 per cent, suggesting that the accumulation of oxidatively damaged proteins in pre-eclampsia is associated with reduced proteasomal activity. To investigate these effects at molecular levels, separation of placental proteins by two-dimensional SDS-PAGE and subsequent anti-proteasome Western blot revealed several sets of approximately 20 kDa and 30 kDa protein subunits in normal placenta which appear at low or undetectable expression levels in pre-eclamptic placenta. Control Western blots against the placenta protein 14 (PP14) demonstrated equal loading and no significant differences in the PP14 protein patterns. These data suggested that alteration of the multifactorial proteasomal protein complex in pre-eclamptic placenta is accompanied by reduced metabolization of oxidatively damaged proteins. Consequently, the accumulation of these damaged proteins in the placenta may be associated with metabolic interference and thus contribute to certain developments of pre-eclampsia. Silver staining of the two-dimensional SDS-PAGE revealed a variety of acidic proteins in the range of 20 kDa and 45 kDa, respectively, which are differentially expressed in normal and pre-eclamptic placenta and thus provide further analytic potential for metabolic interference.


Assuntos
Cisteína Endopeptidases/metabolismo , Complexos Multienzimáticos/metabolismo , Estresse Oxidativo , Placenta/enzimologia , Pré-Eclâmpsia/enzimologia , Dióxido de Carbono/sangue , Dióxido de Carbono/metabolismo , Feminino , Humanos , Placenta/metabolismo , Pré-Eclâmpsia/complicações , Pré-Eclâmpsia/metabolismo , Gravidez , Complexo de Endopeptidases do Proteassoma , Proteínas/metabolismo
11.
Blood ; 97(9): 2830-8, 2001 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-11313278

RESUMO

Treatment of different human leukemia cell variants with the anthracycline adriamycin was associated with a rapid activation of the proteasome. Thus, proliferating U937, TUR, and retrodifferentiated U937 cells exhibited a 4.3-fold, 5.8-fold, and 4.3-fold proteasome activation within 15 minutes after adriamycin treatment, respectively. In contrast, little if any proteasome activation was detectable in a growth-arrested differentiated U937 population following adriamycin treatment. Further analysis of this mechanism revealed a significant reduction of adriamycin-induced proteasome activity after inhibition of poly(ADP-ribose) polymerase (PARP) by 3-aminobenzamide (3-ABA) in the proliferating leukemic cell types. These findings suggested that PARP is involved in the regulation of drug-induced proteasome activation. Indeed, anti-PARP immunoprecipitation experiments of adriamycin-treated cells revealed increasing levels of coprecipitated, enzymatically active proteasome particularly in the proliferating cell variants in contrast to the differentiated U937 cells, with a maximum after 15 minutes, and sensitivity to PARP inhibition by 3-ABA. The specific role of the PARP was investigated in U937 and TUR cell clones stably transfected with a constitutively active antisense PARP (asPARP) vector. Thus, asPARP-TUR cells developed a 25-fold increased sensitivity to adriamycin treatment. Furthermore, we investigated leukemic blasts isolated from acute myelogenous leukemia patients and obtained a similarly enhanced proteasome activity after adriamycin treatment, which was dependent on the PARP and thus could be coprecipitated with anti-PARP antibodies. Transient transfection of leukemic blasts with the asPARP vector significantly reduced the adriamycin-induced proteasome activation. These data suggest that the PARP-associated nuclear proteasome activation represents a potential target within chemotherapeutic defense mechanisms developed by leukemia cells.


Assuntos
Antineoplásicos/farmacologia , Cisteína Endopeptidases/metabolismo , Doxorrubicina/farmacologia , Leucemia Mielomonocítica Aguda/tratamento farmacológico , Leucemia Mielomonocítica Aguda/enzimologia , Complexos Multienzimáticos/metabolismo , Antineoplásicos/uso terapêutico , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Doxorrubicina/uso terapêutico , Ativação Enzimática/efeitos dos fármacos , Humanos , Oligonucleotídeos Antissenso , Complexo de Endopeptidases do Proteassoma , Transfecção , Células U937
12.
Free Radic Biol Med ; 29(10): 995-1004, 2000 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-11084288

RESUMO

Cytotoxic action of a variety of antitumor drugs generate oxidatively modified proteins that are predominantly metabolized via the proteasome. In the present study, a differentiation-retrodifferentiation cell system was exposed to oxidative stress by hydrogen peroxide treatment. Thus, the activity of the nuclear proteasome in proliferating human U937 leukemic cells increased by 2.5-fold after hydrogen peroxide treatment. In contrast, growth-arrested differentiated U937 cells demonstrated 40% less constitutive proteasomal activity, which was not inducible after hydrogen peroxide exposure. After a retrodifferentiation process, however, in which differentiated U937 cells resume autonomous growth again, the proteasomal activity was indistinguishable from that in U937 control cells, both constitutively and after induction of oxidative stress. Moreover, cells of TUR, a differentiation-resistant U937 subclone, expressed an elevated constitutive proteasomal activity that increased by 2.5-fold after oxidative stress. Immunoblot analysis revealed that these differences in proteasomal activities did not correlate with proteasome protein expression but with protein levels of the nuclear enzyme poly-ADP-ribose-polymerase (PARP). Further studies using specific PARP inhibitors revealed that the noninducible proteasome activity in differentiated U937 cells was PARP independent, whereas the increased activity level in oxidatively stressed TUR cells was downregulated upon PARP inhibition. Immunoprecipitation experiments demonstrated a protein-protein interaction of the functional active PARP with the proteasome in correlation with the proteasome activity. Similar results were obtained by analyzing protein carbonyls after oxidative stress. Taken together, these data suggest that proliferating, rather than growth-arrested, cells metabolize oxidatively damaged nuclear proteins via the proteasome by expressing high levels of PARP.


Assuntos
Cisteína Endopeptidases/metabolismo , Monócitos/metabolismo , Complexos Multienzimáticos/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Diferenciação Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Ativação Enzimática , Humanos , Peróxido de Hidrogênio/toxicidade , Monócitos/citologia , Monócitos/efeitos dos fármacos , Estresse Oxidativo , Complexo de Endopeptidases do Proteassoma , Células U937
13.
Cell Death Differ ; 7(9): 795-803, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11042674

RESUMO

Activation of PKC with 5 nM 12-O-tetradecanoylphorbol-13-acetate (TPA) for 72 h in human U937 myeloid leukemia cells is associated with induction of adherence, followed by monocytic differentiation and G0/G1 cell cycle arrest. In this study, we demonstrate that in addition to these effects about 25% of U937 cells accumulated in an apoptotic subG1 phase after TPA treatment. The appearance of these apoptotic suspension cells was detectable throughout the time course of the culture and was independent of TPA concentrations between 0.5 and 500 nM. Experiments with cells synchronized by centrifugal elutriation revealed dominant susceptibility of G1-phase cells to TPA-mediated apoptosis. While adherent cells expressed differentiation markers including the integrin CD11c, this effect was less pronounced in the TPA-treated suspension fraction. Moreover, previous work has demonstrated cell cycle arrest in differentiating U937 cells. Accordingly, PKC activation by TPA treatment was associated with a significant expression of the cdk/cyclin inhibitor p21WAF/CIP/sdi-1 in the adherent population and subsequent G0/G1 cell cycle arrest. In contrast, suspension cells failed to induce significant levels of p21WAF/CIP/sdi-1 after TPA stimulation. Immunoblotting experiments demonstrated no difference in the expression of the pro-apoptotic factors Bax, Bad, and Bak in either control U937 and TPA-treated adherent or suspension cells, respectively. However, anti-apoptotic factors including Bcl-2, Bcl-xL, and Mcl-1 were significantly induced in the adherent population whereas no induction was detectable in the suspension cells. In this context, incubation with the caspase-3/caspase-7 specific tetrapeptide inhibitor DEVD prior to TPA treatment prevented an accumulation of cells in subG1, respectively, demonstrating an involvement of these caspases. Taken together, these data suggest that PKC activation can relay distinct signaling pathways such as induction of adherence coupled with monocytic differentiation and growth arrest, or induction of caspase-mediated apoptosis coupled with the failure to adhere and to differentiate.


Assuntos
Apoptose , Caspases/metabolismo , Diferenciação Celular , Proteína Quinase C/metabolismo , Transdução de Sinais , Acetato de Tetradecanoilforbol/farmacologia , Anexina A5/metabolismo , Antígenos CD18/metabolismo , Inibidores de Caspase , Adesão Celular , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/antagonistas & inibidores , Ciclinas/metabolismo , Ativação Enzimática , Citometria de Fluxo , Fase G1/efeitos dos fármacos , Humanos , Fatores de Tempo , Células U937
14.
Ann N Y Acad Sci ; 907: 1-20, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10818617

RESUMO

The application of the theory of evolution to human social behavior has, along with some illumination, produced friction that occasionally bursts into flame. In this paper we will examine the relationship between the theory of evolution and the social sciences, psychology in particular. We will identify some of the sources of friction between proponents and opponents of applying evolutionary theory to the social sciences, and we will suggest that listening carefully to both sides in the debate points the way to an enriched understanding of human social behavior.


Assuntos
Evolução Biológica , Psicologia , Ciências Sociais , Biologia , Comportamento de Escolha , Cognição , Cultura , Meio Ambiente , Feminino , Humanos , Masculino , Teoria Psicológica , Caracteres Sexuais , Comportamento Sexual
15.
Membr Cell Biol ; 12(6): 793-803, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10512049

RESUMO

We showed that the telomerase activity (TAC) of human promyelocytic leukemic cells U-937 and HL-60 sharply decreased after induction of macrophagal differentiation. Dedifferentiation which occurred several days after removing the inductor was accompanied by the resumption of proliferation and increase of TAC. Telomerase activity significantly decreased also when U-937 cells ceased to proliferate in response to long-term inhibition of the telomerase function by azidothymidine. TAC was observed to decrease slowly for 6-8 days in the course of transition of mouse fibroblasts 3T3 Swiss to the quiescent state. TAC decreased both in serum-deprived cells and in slowly proliferating high-density inhibited cells. During the exit from quiescence and in dedifferentiation, the increase in TAC preceded the resumption of proliferation. In all the cases described the alterations of TAC correlated with alterations in the nonspecific polymerase activity which we had found earlier (D. N. Chernov, Y. E. Yegorov, and S. S. Akimov, DokL Biochemistry 349:55-58 (1996)). The problems of TAC regulation are discussed.


Assuntos
Ciclo Celular , Telomerase/fisiologia , Células 3T3 , Animais , Biomarcadores , Ciclo Celular/fisiologia , Diferenciação Celular/fisiologia , Divisão Celular/fisiologia , Células HL-60 , Humanos , Camundongos , Células U937
16.
Proc Natl Acad Sci U S A ; 96(11): 6223-8, 1999 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-10339569

RESUMO

The 20S proteasome has been shown to be largely responsible for the degradation of oxidatively modified proteins in the cytoplasm. Nuclear proteins are also subject to oxidation, and the nucleus of mammalian cells contains proteasome. In human beings, tumor cells frequently are subjected to oxidation as a consequence of antitumor chemotherapy, and K562 human myelogenous leukemia cells have a higher nuclear proteasome activity than do nonmalignant cells. Adaptation to oxidative stress appears to be one element in the development of long-term resistance to many chemotherapeutic drugs and the mechanisms of inducible tumor resistance to oxidation are of obvious importance. After hydrogen peroxide treatment of K562 cells, degradation of the model proteasome peptide substrate suc-LLVY-MCA and degradation of oxidized histones in nuclei increases significantly within minutes. Both increased proteolytic susceptibility of the histone substrates (caused by modification by oxidation) and activation of the proteasome enzyme complex occur independently during oxidative stress. This rapid up-regulation of 20S proteasome activity is accompanied by, and depends on, poly-ADP ribosylation of the proteasome, as shown by inhibitor experiments, 14C-ADP ribose incorporation assays, immunoblotting, in vitro reconstitution experiments, and immunoprecipitation of (activated) proteasome with anti-poly-ADP ribose polymerase antibodies. The poly-ADP ribosylation-mediated activated nuclear 20S proteasome is able to remove oxidatively damaged histones more efficiently and therefore is proposed as an oxidant-stimulatable defense or repair system of the nucleus in K562 leukemia cells.


Assuntos
Núcleo Celular/metabolismo , Cisteína Endopeptidases/metabolismo , Histonas/metabolismo , Peróxido de Hidrogênio/farmacologia , Complexos Multienzimáticos/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Adenosina Difosfato Ribose/metabolismo , Adenosina Trifosfatases/metabolismo , Radioisótopos de Carbono , Cumarínicos/metabolismo , Ativação Enzimática , Corantes Fluorescentes , Histonas/efeitos dos fármacos , Humanos , Células K562 , Oligopeptídeos/metabolismo , Oxirredução , Complexo de Endopeptidases do Proteassoma , Especificidade por Substrato
17.
Exp Cell Res ; 247(2): 534-42, 1999 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-10066381

RESUMO

Exposure of the two related human leukemic cell lines U937 and TUR to chemotherapeutic compounds resulted in opposite effects on induction and resistance to apoptosis. Incubation of U937 cells with 1-beta-d-arabinofuranosylcytosine or the etoposide VP-16 was accompanied by growth arrest in G0/G1 of the cell cycle and an accumulation of a population in the sub-G1 phase which exhibited characteristics typical for the apoptotic pathway. In contrast, human TUR leukemia cells demonstrated no significant effects after a similar treatment with Ara-C and VP-16. Thus, TUR cells continued to proliferate in the presence of these anti-cancer drugs and the number of apoptotic cells as evaluated by propidium iodide staining and the detection of internucleosomal DNA fragmentation was significantly reduced when compared to the parental U937 cells. Similar effects were observed upon serum-starvation demonstrating resistance to apoptosis in TUR cells. Whereas induction of apoptosis is regulated by a network of distinct factors including the activation of proteolytically active caspases, we investigated these pathways in both cell lines. U937 cells demonstrated activation of the 32-kDa caspase-3 upon drug treatment by cleavage into the 20-kDa activated form. However, there was no 20-kDa caspase-3 fragment detectable in TUR cells. Simultaneously, the enzymatic activity of caspase-3 was significantly increased in drug-treated U937 cells as measured in vitro by enhanced metabolization of a fluorescence substrate and in vivo by cleavage of an appropriate substrate for caspase-3, namely, protein kinase Cdelta. In contrast, there was little if any caspase-3 activation detectable in drug-treated TUR cells. Taken together, these data suggest a signaling defect in the activation of the caspase-3 proteolytic system in TUR cells upon treatment with chemotherapeutic compounds which is associated with resistance to apoptosis in these human leukemia cells.


Assuntos
Apoptose , Caspases/metabolismo , Isoenzimas/metabolismo , Proteína Quinase C/metabolismo , Transdução de Sinais , Caspase 3 , Citarabina/farmacologia , Ativação Enzimática , Etoposídeo/farmacologia , Humanos , Leucemia , Inibidores da Síntese de Ácido Nucleico/farmacologia , Proteína Quinase C-delta , Células Tumorais Cultivadas , Células U937
20.
Exp Cell Res ; 243(1): 207-11, 1998 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-9716464

RESUMO

Cytochemically detectable activity of endogenous beta-galactosidase was found at pH 6.0 in Swiss 3T3 cells after long-term incubation in low serum or in the presence of heparin concentrations known to reversibly inhibit cell proliferation. A high percentage of beta-galactosidase-positive cells were detected in U937 and HL60 cultures at the late stage of macrophage-like differentiation induced by TPA. Interestingly, a small number of beta-galactosidase-positive cells were found even in the growing Swiss 3T3 cultures. These positive cells expressed morphological features similar to those of senescent cells. Thus, the activity of beta-galactosidase at pH 6.0 cannot be considered an exclusive marker of senescent cells since it is expressed in other types of nonproliferating cells.


Assuntos
Fibroblastos/enzimologia , beta-Galactosidase/metabolismo , Células 3T3 , Animais , Diferenciação Celular , Divisão Celular , Linhagem Celular , Senescência Celular , Fibroblastos/citologia , Concentração de Íons de Hidrogênio , Camundongos
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