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1.
Zhonghua Zhong Liu Za Zhi ; 41(4): 251-256, 2019 Apr 23.
Artigo em Chinês | MEDLINE | ID: mdl-31014049

RESUMO

Objective: To determine the clinical benefits of internal mammary sentinel lymph node biopsy (IM-SLNB) acquired by breast cancer patients with clinically positive axillary lymph node (ALN), and further optimize the IM-SLNB indications. Methods: All primary breast cancer patients with clinically positive ALN from February 2014 to September 2017 were prospectively recruited in this study. IM-SLNB was performed under the guidance of the modified injection technique. The success rate and visualization rate of IM-SLNB, metastatic rate of internal mammary sentinel lymph node (IMSLN) and its related factors were analyzed, and the clinical benefits were accessed according to the current guidelines. Results: Among 126 patients, all of 94 patients (74.6%) who showed internal mammary drainage successfully underwent IM-SLNB. The incidence of internal mammary artery bleeding and pleural lesion were 4.3%(4/94) and 9.6%(9/94), respectively. The metastatic rate of IMSLN was 38.3% (36/94), which was significantly associated with the number of positive ALN (P<0.001) and tumor size (P=0.024). The lymph node staging of 94 patients who underwent IM-SLNB was more accurate. Among them, 36 cases with positive IMSLN underwent internal mammary radiotherapy (IMRT), while the other 58 cases with negative IMSLN avoided radiotherapy. Conclusions: IM-SLNB should be routinely performed in patients with positive ALN. IM-SLNB can provide more accurate staging and guide tailored IMRT to benefit more breast cancer patients.


Assuntos
Neoplasias da Mama/patologia , Biópsia de Linfonodo Sentinela , Axila , Neoplasias da Mama/tratamento farmacológico , Feminino , Humanos , Metástase Linfática , Estadiamento de Neoplasias , Medicina de Precisão , Estudos Prospectivos , Linfonodo Sentinela/patologia , Biópsia de Linfonodo Sentinela/efeitos adversos , Biópsia de Linfonodo Sentinela/estatística & dados numéricos
2.
Zhonghua Er Ke Za Zhi ; 55(4): 288-293, 2017 Apr 02.
Artigo em Chinês | MEDLINE | ID: mdl-28441826

RESUMO

Objective: To explore clinical characteristics, treatment, and prognosis of a family with childhood-onset rapid-onset dystonia parkinsonism (RDP) caused by ATP1A3 gene mutation and review literatures. Method: The clinical data of a RDP child, his brother and mother had been analyzed retrospectively. This family was admitted to Xiangya Hospital in January 2016. DNA samples were analyzed by the next-generation sequencing and confirmed by Sanger sequencing. Related literature from PubMed, Online Mendelian Inheritance in Man (OMIM), CNKI and Wanfang databases to date (up to October 2016) with"Rapid-onset dystonia-parkinsonism""RDP""DYT12" as key words was reviewed. Result: The proband boy was three years and four months old (April 2015) when he had the first attack of the disease. After a febricity, he suddenly acquired acute aphasia and limb movement disorder. Rehabilitation therapy and supportive treatment made his speech gradually recovered but still slurred. However, his abnormal walking posture still existed. Nine months later (January 2016, 4 years and one months old), symptoms including aphasia, dysphagia, and weakness with rostrocaudal gradient reoccured after fever. The disease progressed to the critical condition within 24 hours. He"seizured" four times with tonic spasms of limbs but without loss of consciousness. Family history showed his grandparents were consanguineous marriage. His mother and brother also developed abnormal gait and dysarthria after an infection before primary school age. Their symptoms improved gradually without relapsing. However, they did not recover entirely with mild intellectual disability. His mother had a healthy brother and sister. This proband had no other siblings but the brother. Heterozygous missense mutation p. R756H in ATP1A3 gene was detected in this proband, his mother and his brother. This mutation had been reported pathogenically related to RDP, and it located in highly conserved gene region. Benzodiazepine was used for the proband and his brother, with the proband being improved better although not completely. Meanwhile, benzodiazepine had no significant effect on his mother because of poor compliance. This is the first case report of RDP in China. The mutations of ATP1A3 have been previously reported in 51 patients including 6 large families and 16 other unrelated patients. A total of 14 different mutations in ATP1A3 gene with RDP have been reported to date, including 12 missense mutations, a 3-bp in-frame deletion, and a 3-bp in-frame insertion. The sporadic cases all had the typical clinical phenotypes of RDP, such as the abrupt onset of dysarthria, dysphagia, limb dystonia with bradykinesia, and postural instability. The symptoms of bulbar and arms were much more obvious. It was hard to diagnose RDP in a family because some patients had typical symptoms of RDP, while the others might experience from mild symptoms to no symptoms, which might be related to incomplete penetrance of RDP. Two cases carrying the same mutation as our patients also presented some overlapping phenotypes. Conclusion: The p. R756H heterozygous mutation in ATP1A3 gene is the pathogenic mutation of RDP, analysis of genotype-phenotype correlations of RDP will be very important and meaningful.


Assuntos
Distúrbios Distônicos/genética , ATPase Trocadora de Sódio-Potássio/genética , Pré-Escolar , China , Distonia , Extremidades , Feminino , Heterozigoto , Humanos , Masculino , Transtornos dos Movimentos , Mutação , Fenótipo , Irmãos
3.
Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 30(20): 1608-1611, 2016 Oct 20.
Artigo em Chinês | MEDLINE | ID: mdl-29871155

RESUMO

Objective:To investigate the expression of PACAP protein in chronic rhinosinusitis without/with nasal polyps and refractory chronic rhinosinusitis.Method: Fifty-three patients with nasal polyps,70 cases with chronic sinusitis, 28 patients with refractory chronic rhinosinusitis and 20 control cases were enrolled for this study. The expression of PACAP protein was detected by immunochemistry.Result: ①PACAP protein were expressed in nasal epithelium,glandular epithelium and goblet cells;②The positive intensity of PACAP was" +", " +++", "--+",and " ++" in nasal polyps, chronic rhinosinusitis, refractory chronic rhinosinusitis, and control group, respectively.Conclusion:PACAP protein mainly locates in nasal epithelium,glandular epithelium and goblet cells. Reduced expression of PACAP may be related with onset of chronic rhiniosinusitis without/with nasal polyps.

4.
Bone Marrow Transplant ; 49(1): 80-6, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23974608

RESUMO

Autologous stem cell rescue (ASCT) following high-dose myeloablative chemotherapy is considered to be a therapeutic option for many multiple myeloma (MM) patients; however relapse post ASCT presents a major challenge. The oncolytic potential of reovirus has been previously demonstrated and is currently undergoing phase I monotherapy clinical trials for MM and phase II/III clinical trials for solid tumors. Here we tested the hypothesis that reovirus can successfully purge MM in a murine model that partially recapitulates human MM. RPMI 8226, MM1S, H929 and U266 human myeloma cell lines were exposed to reovirus and oncolysis was assessed. Apheresis product admixed with MM cells was purged with live reovirus (LV) or dead virus (DV) and purging efficacy was monitored via flow cytometry, reverse transcribed-PCR (RT-PCR) and disease relapse in non obese diabetic/severe combined immune deficient (NOD/SCID) mice. Significant LV purging was seen with MM1S, H929 and U266 and the complete ex vivo purging achieved with RPMI 8226 was confirmed by flow cytometry, RT-PCR and absence of disease relapse in vivo. Mice that received LV-purged autografts exhibited 100% survival in comparison to mice that received DV-purged controls. Reovirus's unique ability to kill MM while sparing hematopoietic stem cells places it as an attractive purging agent for MM during ASCT.


Assuntos
Purging da Medula Óssea/métodos , Mieloma Múltiplo/terapia , Terapia Viral Oncolítica , Reoviridae , Animais , Remoção de Componentes Sanguíneos , Linhagem Celular , Linhagem Celular Tumoral , Citometria de Fluxo , Proteínas de Fluorescência Verde/química , Humanos , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Recidiva , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Resultado do Tratamento
5.
Gene Ther ; 11(21): 1579-89, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15372068

RESUMO

Brain and leptomeningeal metastases are common in breast cancer patients and our current treatments are ineffective. Reovirus type 3 is a replication competent, naturally occurring virus that usurps the activated Ras-signaling pathway (or an element thereof) of tumor cells and lyses them but leaves normal cells relatively unaffected. In this study we evaluated reovirus as an experimental therapeutic in models of central nervous system (CNS) metastasis from breast cancer. We found all breast cancer cell lines tested were susceptible to reovirus, with > 50% of these cells lysed within 72 h of infection. In vivo neurotoxicity studies showed only mild local inflammation at the injection site and mild communicating hydrocephalus with neither diffuse encephalitis nor behavioral abnormalities at the therapeutically effective dose of reovirus (intracranial) (ie 10(7) plaque-forming units) or one dose level higher. In vivo, a single intratumoral administration of reovirus significantly reduced the size of tumors established from two human breast cancer cell lines and significantly prolonged survival. Intrathecal administration of reovirus also remarkably prolonged survival in an immunocompetent racine model of leptomeningeal metastases. These data suggest that the evaluation of reovirus as an experimental therapeutic for CNS metastases from breast cancer is warranted.


Assuntos
Neoplasias Encefálicas/secundário , Neoplasias Encefálicas/terapia , Neoplasias da Mama/terapia , Orthoreovirus Mamífero 3 , Infecções por Reoviridae/complicações , Animais , Neoplasias Encefálicas/virologia , Morte Celular , Linhagem Celular Tumoral , Feminino , Proteínas de Fluorescência Verde/genética , Humanos , Injeções Intralesionais , Dose Letal Mediana , Neoplasias Meníngeas/secundário , Neoplasias Meníngeas/terapia , Neoplasias Meníngeas/virologia , Camundongos , Camundongos Nus , Modelos Animais , Neoplasias Experimentais , Transfecção/métodos
6.
J Natl Cancer Inst ; 93(12): 903-12, 2001 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-11416111

RESUMO

BACKGROUND: Reovirus is a naturally occurring oncolytic virus that usurps activated Ras-signaling pathways of tumor cells for its replication. Ras pathways are activated in most malignant gliomas via upstream signaling by receptor tyrosine kinases. The purpose of this study was to determine the effectiveness of reovirus as an experimental treatment for malignant gliomas. METHODS: We investigated whether reovirus would infect and lyse human glioma cell lines in vitro. We also tested the effect of injecting live reovirus in vivo on human gliomas grown subcutaneously or orthotopically (i.e., intracerebrally) in mice. Finally, reovirus was tested ex vivo against low-passage cell lines derived from human glioma specimens. All P values were two-sided. RESULTS: Reovirus killed 20 (83%) of 24 established malignant glioma cell lines tested. It caused a dramatic and often complete tumor regression in vivo in two subcutaneous (P =.0002 for both U251N and U87) and in two intracerebral (P =.0004 for U251N and P =.0009 for U87) human malignant glioma mouse models. As expected, serious toxic effects were found in these severely immunocompromised hosts. In a less immunocompromised mouse model, a single intratumoral inoculation of live reovirus led to a dramatic prolongation of survival (compared with control mice treated with dead virus; log-rank test, P<.0001 for both U251N and U87 cell lines). The animals treated with live virus also appeared to be healthier and gained body weight (P =.0001). We then tested the ability of reovirus to infect and kill primary cultures of brain tumors removed from patients and found that it killed nine (100%) of nine glioma specimens but none of the cultured meningiomas. CONCLUSIONS: Reovirus has potent activity against human malignant gliomas in vitro, in vivo, and ex vivo. Oncolysis with reovirus may be a potentially useful treatment for a broad range of human cancers.


Assuntos
Neoplasias Encefálicas/terapia , Glioma/terapia , Orthoreovirus Mamífero 3/fisiologia , Animais , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/virologia , Feminino , Glioma/patologia , Glioma/virologia , Humanos , Masculino , Orthoreovirus Mamífero 3/isolamento & purificação , Camundongos , Camundongos Endogâmicos NOD , Camundongos Nus , Camundongos SCID , Taxa de Sobrevida , Transplante Heterólogo , Células Tumorais Cultivadas
7.
Mol Cell Biol ; 20(5): 1526-36, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10669730

RESUMO

We have previously shown that activation of extracellular signal-regulated kinase (Erk) by epidermal growth factor (EGF) treatment was significantly decreased in mouse fibroblast cells expressing a mutant Shp-2 molecule lacking 65 amino acids in the SH2-N domain, Shp-2(Delta46-110). To address the molecular mechanism for the positive role of Shp-2 in mediating Erk induction, we evaluated the activation of signaling components upstream of Erk in Shp-2 mutant cells. EGF-stimulated Ras, Raf, and Mek activation was significantly attenuated in Shp-2 mutant cells, suggesting that Shp-2 acts to promote Ras activation or to suppress the down-regulation of activated Ras. Biochemical analyses indicate that upon EGF stimulation, Shp-2 is recruited into a multiprotein complex assembled on the Gab1 docking molecule and that Shp-2 seems to exert its biological function by specifically dephosphorylating an unidentified molecule of 90 kDa in the complex. The mutant Shp-2(Delta46-110) molecule failed to participate in the Gab1-organized complex for dephosphorylation of p90, correlating with a defective activation of the Ras-Raf-Mek-Erk cascade in EGF-treated Shp-2 mutant cells. Evidence is also presented that Shp-2 does not appear to modulate the signal relay from EGF receptor to Ras through the Shc, Grb2, and Sos proteins. These results begin to elucidate the mechanism of Shp-2 function downstream of a receptor tyrosine kinase to promote the activation of the Ras-Erk pathway, with potential therapeutic applications in cancer treatment.


Assuntos
Fator de Crescimento Epidérmico/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Tirosina Fosfatases/metabolismo , Transdução de Sinais , Proteínas ras/metabolismo , Animais , Linhagem Celular , Peptídeos e Proteínas de Sinalização Intracelular , Sistema de Sinalização das MAP Quinases , Camundongos , Complexos Multiproteicos , Proteína Tirosina Fosfatase não Receptora Tipo 11 , Proteína Tirosina Fosfatase não Receptora Tipo 6
8.
Oncogene ; 17(4): 441-8, 1998 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-9696037

RESUMO

The SH2-containing tyrosine phosphatase Shp-2 appears to function downstream of a variety of growth factor receptors and might play a positive role in cell proliferation. Here we report that expression of the beta subunit of platelet-derived growth factor receptor (PDGFR-beta) was specifically downregulated in mutant fibroblasts lacking a functional Shp-2, while the levels of PDGFR-alpha EGFR and IGFIR were not changed. PDGF-stimulated DNA synthesis and extracellular signal regulated kinase (Erk) activation was severely suppressed in mutant cells. RasGAP, that responds to activation of PDGFR-beta but not PDGFR-alpha, was not phosphorylated on tyrosine in mutant cells upon PDGF-treatment. Northern blot analysis failed to detect PDGFR-beta mRNA in mutant cells. The transcription initiation from the PDGFR-beta gene promoter was not significantly changed, but the half-life of its mRNA was shortened in Shp-2 mutant cells. These observations indicate that Shp-2 not only participates in transmission of signals from growth factor receptors but also plays a specific role in the control of the PDGFR-beta expression. We propose that this is an important mechanism for the positive control of cell proliferation by Shp-2.


Assuntos
Regulação para Baixo , Proteínas Tirosina Fosfatases/fisiologia , Receptores do Fator de Crescimento Derivado de Plaquetas/biossíntese , Domínios de Homologia de src , Animais , Becaplermina , Linhagem Celular , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Camundongos Endogâmicos C57BL , Mitógenos/metabolismo , Mitógenos/farmacologia , Mutagênese , Fator de Crescimento Derivado de Plaquetas/metabolismo , Fator de Crescimento Derivado de Plaquetas/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 11 , Proteína Tirosina Fosfatase não Receptora Tipo 6 , Proteínas Tirosina Fosfatases/genética , Proteínas Proto-Oncogênicas c-sis , RNA Mensageiro , Receptor beta de Fator de Crescimento Derivado de Plaquetas , Receptores do Fator de Crescimento Derivado de Plaquetas/genética , Proteínas Tirosina Fosfatases Contendo o Domínio SH2 , Transdução de Sinais
9.
J Biol Chem ; 273(9): 4904-8, 1998 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-9478933

RESUMO

Shp-2 is a widely expressed cytoplasmic tyrosine phosphatase with two SH2 domains. A targeted mutant allele of the Shp-2 gene with a deletion of 65 amino acids in the NH2-terminal SH2 domain was created that leads to embryonic lethality at mid-gestation in homozygous mutant mice. To define the Shp-2 function in cell signaling, we have established mutant fibroblast cell lines, and have examined the effect of the Shp-2 mutation on extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) mitogen-activated protein (MAP) kinase pathways. Insulin-like growth factor (IGF)-I-induced ERK activation was completely abolished, while ERK activity upon platelet-derived growth factor and epidermal growth factor stimulation was significantly reduced and shortened in mutant cells. Stimulation of ERK by phorbol 12-myristate 13-acetate was not affected in mutant cells, but the phorbol 12-myristate 13-acetate-induced ERK activity decayed much faster compared with that in wild-type cells. In contrast, JNK activation upon heat shock was significantly enhanced in Shp-2 mutant cells. Based on these results, we conclude that Shp-2 plays differential positive regulatory roles in various mitogenic signaling pathways leading to ERK activation, and that Shp-2 is a negative effector in JNK activation by cellular stress. This is the first evidence that a tyrosine phosphatase has opposite effects in mediating the activation of ERK and JNK MAP kinases.


Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Proteínas Quinases Ativadas por Mitógeno , Proteínas Tirosina Fosfatases/metabolismo , Animais , Linhagem Celular , Ativação Enzimática/efeitos dos fármacos , Fator de Crescimento Epidérmico/farmacologia , Fibroblastos/citologia , Fator de Crescimento Insulin-Like I/farmacologia , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Quinases JNK Ativadas por Mitógeno , Camundongos , Camundongos Mutantes , Fosforilação , Fator de Crescimento Derivado de Plaquetas/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 11 , Proteína Tirosina Fosfatase não Receptora Tipo 6 , Proteínas Tirosina Fosfatases/genética , Proteínas Tirosina Fosfatases Contendo o Domínio SH2 , Transdução de Sinais , Acetato de Tetradecanoilforbol/farmacologia
10.
Mol Cell Biol ; 17(9): 5499-507, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9271425

RESUMO

Shp-1 and Shp-2 are cytoplasmic protein tyrosine phosphatases that contain two Src homology 2 (SH2) domains. A negative regulatory role of Shp-1 in hematopoiesis has been strongly implicated by the phenotype of motheaten mice with a mutation in the Shp-1 locus, which is characterized by leukocyte hypersensitivity, deregulated mast cell function, and excessive erythropoiesis. A targeted deletion of 65 amino acids in the N-terminal SH2 (SH2-N) domain of Shp-2 leads to an embryonic lethality at midgestation in homozygous mutant mice. To further dissect the Shp-2 function in hematopoietic development, we have isolated homozygous Shp-2 mutant embryonic stem (ES) cells. Significantly reduced hematopoietic activity was observed when the mutant ES cells were allowed to differentiate into embryoid bodies (EBs), compared to the wild-type and heterozygous ES cells. Further analysis of ES cell differentiation in vitro showed that mutation in the Shp-2 locus severely suppressed the development of primitive and definitive erythroid progenitors and completely blocked the production of progenitor cells for granulocytes-macrophages and mast cells. Reverse transcriptase PCR analysis of the mutant EBs revealed reduced expression of several specific marker genes that are induced during blood cell differentiation. Stem cell factor induction of mitogen-activated protein kinase activity was also blocked in Shp-2 mutant cells. Taken together, these results indicate that Shp-2 is an essential component and primarily plays a positive role in signaling pathways that mediate hematopoiesis in mammals. Furthermore, stimulation of its catalytic activity is not sufficient, while interaction via the SH2 domains with the targets or regulators is necessary for its biological functions in cells. The in vitro ES cell differentiation assay can be used as a biological tool in dissecting cytoplasmic signaling pathways.


Assuntos
Células-Tronco Hematopoéticas/citologia , Proteínas Tirosina Fosfatases/genética , Domínios de Homologia de src , Animais , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Diferenciação Celular/genética , Linhagem Celular , Ativação Enzimática , Expressão Gênica , Homozigoto , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Mutação Puntual , Reação em Cadeia da Polimerase , Proteína Tirosina Fosfatase não Receptora Tipo 11 , Proteína Tirosina Fosfatase não Receptora Tipo 6 , Proteínas Tirosina Fosfatases Contendo o Domínio SH2 , Deleção de Sequência
11.
J Biol Chem ; 271(21): 12129-32, 1996 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-8647802

RESUMO

A human cytoplasmic signaling protein has been cloned that possesses the same structural arrangement of SH3-SH2-SH3 domains as Grb2. This protein is designated Grap for Grb2-related adaptor protein. The single 2.3-kilobase (kb) grap transcript was expressed predominantly in thymus and spleen, while the ubiquitously expressed grb2 gene produced two mRNA species of 3.8 and 1.5 kb. Grap and Grb2 consist of 217 amino acids and share 59% amino acid sequence identity, with highest homology in the N-terminal SH3 domain. The GrapSH2 domain interacts with ligand-activated receptors for stem cell factor (c-kit) and erythropoietin (EpoR). Grap also forms a stable complex with the Bcr-Abl oncoprotein via its SH2 domain in K562 cells. Furthermore, Grap is associated with a Ras guanine nucleotide exchange factor mSos1, primarily through its N-terminal SH3 domain. These results show that a family of Grb2-like proteins exist and couple signals from receptor and cytoplasmic tyrosine kinases to the Ras signaling pathway.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Transporte/metabolismo , Proteínas Tirosina Quinases/metabolismo , Proteínas ras/metabolismo , Sequência de Aminoácidos , DNA Complementar , Humanos , Dados de Sequência Molecular , Fosfoproteínas/metabolismo , Ligação Proteica , Homologia de Sequência de Aminoácidos , Transdução de Sinais
12.
Chin Med J (Engl) ; 107(1): 57-9, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8187574

RESUMO

Postoperative reflux esophagitis is a common complication after partial removal of the esophagus and the whole gastric cardia for reconstruction through esophagogastrostomy. In 10 cases, the lower esophageal sphincter (LES) was preserved for a length of 2.05 +/- 0.33cm (mean +/- S) during partial esophagectomy for benign or malignant lesion at the middle and lower portion of the thoracic esophagus. The mean value of the LES pressures measured two weeks after operations was 2.40 +/- 0.64 kPa (18 +/- 4.8 mmHg) and the postoperative X-ray barium meal examination revealed no evidence of gastroesophageal reflux. Our study suggested that the preserved LES should effectively act as a functional barrier against the development of reflux esophagitis.


Assuntos
Esofagectomia/métodos , Junção Esofagogástrica , Refluxo Gastroesofágico/prevenção & controle , Complicações Pós-Operatórias/prevenção & controle , Carcinoma de Células Escamosas/cirurgia , Divertículo Esofágico/cirurgia , Neoplasias Esofágicas/cirurgia , Esofagectomia/efeitos adversos , Feminino , Refluxo Gastroesofágico/etiologia , Humanos , Masculino
13.
J Mol Cell Cardiol ; 21(10): 1009-16, 1989 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2531229

RESUMO

Sarcolemmal vesicles isolated from bovine heart were preincubated at 37 degrees C with an oxygen radical generating system consisting of 1 mM dithiothreitol (DTT) and 50 microM FeSO4. Exposure of the vesicles for 1 to 40 mins stimulated Na+/Ca2+ exchange about 2.5-fold. The DTT/Fe2+ treatment decreased the apparent Km for Ca2+ of Nai+-dependent Ca2+ uptake by 80% (from 63 to 13 microM). The effect on Vmax was much smaller however. The resulting stimulation of exchange activity was diminished by the presence of desferrioxamine (95%) or catalase (60%). In contrast, superoxide dismutase and sodium formate did not prevent the effects of DTT/Fe2+ on the exchanger. Neither Zn2+ nor Ga3+ could replace Fe2+ in the stimulation of Na+/Ca2+ exchange. Passive Ca2+ efflux was determined by first allowing Na+/Ca2+ exchange to continue to plateau values and then diluting the loaded vesicles in the presence of EGTA. Ca2+ leakage from the vesicles was slightly but significantly (P less than 0.05) increased by the action of DTT/Fe2+, the rate constants for the passive Ca2+ efflux being 0.22 and 0.26/min in control and treated groups, respectively. The calcium loading observed in myocytes in ischemia/reperfusion injury suggests that the stimulation of Na+/Ca2+ exchange by active oxygen may moderate the myocardial response to oxygen mediated injuries including ischemia/reperfusion injury. However, the clinical relevance of these phenomena is far from clear as the stimulation depends in part on the Km for Ca2+ prior to treatment.


Assuntos
Adenosina Trifosfatases/metabolismo , Cálcio/metabolismo , Ditiotreitol/farmacologia , Compostos Férricos/farmacologia , Coração/efeitos dos fármacos , Miocárdio/metabolismo , Oxigênio/farmacologia , Sarcolema/efeitos dos fármacos , Animais , Antioxidantes/farmacologia , Transporte Biológico Ativo/efeitos dos fármacos , Bovinos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Radicais Livres , Miocárdio/citologia , Sarcolema/metabolismo
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