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1.
PLoS Genet ; 8(5): e1002669, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22570631

RESUMO

Heat stress commonly leads to inhibition of photosynthesis in higher plants. The transcriptional induction of heat stress-responsive genes represents the first line of inducible defense against imbalances in cellular homeostasis. Although heat stress transcription factor HsfA2 and its downstream target genes are well studied, the regulatory mechanisms by which HsfA2 is activated in response to heat stress remain elusive. Here, we show that chloroplast ribosomal protein S1 (RPS1) is a heat-responsive protein and functions in protein biosynthesis in chloroplast. Knockdown of RPS1 expression in the rps1 mutant nearly eliminates the heat stress-activated expression of HsfA2 and its target genes, leading to a considerable loss of heat tolerance. We further confirm the relationship existed between the downregulation of RPS1 expression and the loss of heat tolerance by generating RNA interference-transgenic lines of RPS1. Consistent with the notion that the inhibited activation of HsfA2 in response to heat stress in the rps1 mutant causes heat-susceptibility, we further demonstrate that overexpression of HsfA2 with a viral promoter leads to constitutive expressions of its target genes in the rps1 mutant, which is sufficient to reestablish lost heat tolerance and recovers heat-susceptible thylakoid stability to wild-type levels. Our findings reveal a heat-responsive retrograde pathway in which chloroplast translation capacity is a critical factor in heat-responsive activation of HsfA2 and its target genes required for cellular homeostasis under heat stress. Thus, RPS1 is an essential yet previously unknown determinant involved in retrograde activation of heat stress responses in higher plants.


Assuntos
Arabidopsis , Proteínas de Cloroplastos , Proteínas de Ligação a DNA/genética , Proteínas de Choque Térmico/genética , Resposta ao Choque Térmico , Proteínas de Plantas/genética , Proteínas Ribossômicas/genética , Fatores de Transcrição/genética , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis , Proteínas de Cloroplastos/genética , Proteínas de Cloroplastos/metabolismo , Cloroplastos/genética , Cloroplastos/metabolismo , Cloroplastos/fisiologia , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica de Plantas , Fatores de Transcrição de Choque Térmico , Proteínas de Choque Térmico/metabolismo , Resposta ao Choque Térmico/genética , Mutação , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Interferência de RNA , Proteínas Ribossômicas/metabolismo , Fatores de Transcrição/metabolismo
2.
Mol Plant ; 5(5): 1082-99, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22402261

RESUMO

Sedoheptulose-1,7-bisphosphatase (SBPase) is a Calvin cycle enzyme and functions in photosynthetic carbon fixation. We found that SBPase was rapidly carbonylated in response to methyl viologen (MV) treatments in detached leaves of Arabidopsis plants. In vitro activity analysis of the purified recombinant SBPase showed that SBPase was carbonylated by hydroxyl radicals, which led to enzyme inactivation in an H(2)O(2) dose-dependent manner. To determine the conformity with carbonylation-caused loss in enzymatic activity in response to stresses, we isolated a loss-of-function mutant sbp, which is deficient in SBPase-dependent carbon assimilation and starch biosynthesis. sbp mutant exhibited a severe growth retardation phenotype, especially for the developmental defects in leaves and flowers where SBPASE is highly expressed. The mutation of SBPASE caused growth retardation mainly through inhibition of cell division and expansion, which can be partially rescued by exogenous application of sucrose. Our findings demonstrate that ROS-induced oxidative damage to SBPase affects growth, development, and chloroplast biogenesis in Arabidopsis through inhibiting carbon assimilation efficiency. The data presented here provide a case study that such inactivation of SBPase caused by carbonyl modification may be a kind of adaptation for plants to restrict the operation of the reductive pentose phosphate pathway under stress conditions.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Arabidopsis/crescimento & desenvolvimento , Carbono/metabolismo , Estresse Oxidativo , Monoéster Fosfórico Hidrolases/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Regulação para Baixo , Monoéster Fosfórico Hidrolases/genética , Carbonilação Proteica
3.
Zhonghua Wai Ke Za Zhi ; 47(5): 326-8, 2009 Mar 01.
Artigo em Chinês | MEDLINE | ID: mdl-19595003

RESUMO

OBJECTIVE: To evaluate the methods of diagnosis and surgical treatment for nonfunctional islet cell tumor (NICT). METHODS: Forty-four patients with non-functional islet cell tumor treated at the First Affiliated Hospital of Nanjing Medical University during January 1968 to June 2008 were analyzed retrospectively. There were 9 males and 35 females, aged from 7- to 70-years-old. Clinical manifestation: 15 cases (34.1%) of abdominal masses, 17 patients (38.6%) with epigastric or back pain, 5 cases of jaundice, 5 cases (11.4%) for upper abdominal fullness or vomiting, 10 cases (22.7%) of pancreatic tumor noticed by routine health checkups or imaging examinations. Imaging examination: CT scan, sonography, ERCP, MRI, upper GI series were performed in 33 (75.0%), 16 (36.4%), 6 (13.6%), 2 (4.5%), and 10 cases (22.7%) respectively. Operation methods: 39 patients (88.6%) underwent surgical resection and the other 5 patients did not. COMPLICATIONS: pancreatic fistula in 7 patients (15.9%), intra-abdominal bleeding in 4 (9.1%), gastrojejunal anastomosis outlet obstruction in 1 (2.3%), biliary fistula in 2 (4.5%) and incisional infection in 3 (6.8%). Surgery related mortality happened in 2 patients (4.5%), both treated before 1999. Twenty-five patients underwent operation between January 1999 and June 2008 were followed up for 6 to 108 months. All survive except one died 75 months after the surgery for unknown reason. CONCLUSIONS: No specific clinical manifestation is recognized for non-functional islet cell tumor. Spiral CT is an optimal diagnostic method, while surgery is the first choice for treatment. Middle segmental pancreatectomy has become an alternative surgical protocol for NICT.


Assuntos
Adenoma de Células das Ilhotas Pancreáticas/diagnóstico , Adenoma de Células das Ilhotas Pancreáticas/cirurgia , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/cirurgia , Adolescente , Adulto , Idoso , Criança , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Pancreatectomia/métodos , Prognóstico , Estudos Retrospectivos , Adulto Jovem
4.
Zhonghua Yi Xue Za Zhi ; 88(28): 1952-5, 2008 Jul 22.
Artigo em Chinês | MEDLINE | ID: mdl-19062733

RESUMO

OBJECTIVE: To investigate the expression of radio-inducible herpes simplex virus thymidine kinase (TK) suicide gene controlled by early growth response-1 (Egr-1) promoter in pancreatic cancer cells. METHODS: Adenoviral vector pAdEgr-1-TK containing green fluorescent protein (GFP) was constructed. Human pancreatic cancer cells of the line PC-3 were cultured, transfected with pAdEgr-1-TK, and then exposed to 60Co source gamma-radiation at the doses of 0, 5, 7.5, 10, 15, and 20 Gy respectively for 24 hours. RT-PCR and Western blotting were used to detect the TK mRNA and protein expression in the PC3 cells. RESULTS: The TK mRNA expression levels of the PC3 cells exposed to y-radiation at the doses of 0, 5, 7.5, 10, 15, and 20 Gy respectively were (67.3 +/- 2.1)%, (89.3 +/- 1.0)%, (114.7 +/- 5.7)%, (140.5 +/- 3.1)%, (134.5 +/- 4.0)%, and (117.4 +/- 3.4)% respectively. The TK mRNA expression level was markedly increased after exposure to gamma-radiation, especially that t the dose of 10 Gy (all P < 0.01). The TK protein expression levels of the PC3 cells exposed to y-radiation at the doses of 0, 5, 7.5, 10, 15, and 20 Gy were (5.4 +/- 0.7)%, (7.6 +/- 0.9)%, (21.5 +/- 1.5)%, (35.7 +/- l1.4)%, (32.1 +/- 1.2)%, and (28.8 +/- 1.5)% respectively. CONCLUSION: The Egr-1 promoter causes high expression of TK suicide gene in cancer cells after exposure to 60Co-gamma-radiation. These data provide an experimental basis for gene therapy.


Assuntos
Proteína 1 de Resposta de Crescimento Precoce/genética , Genes Transgênicos Suicidas/genética , Regiões Promotoras Genéticas/genética , Timidina Quinase/genética , Animais , Western Blotting , Linhagem Celular Tumoral , Expressão Gênica/efeitos da radiação , Vetores Genéticos , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Camundongos , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Simplexvirus/genética , Timidina Quinase/metabolismo , Transfecção
5.
Chin Med J (Engl) ; 120(15): 1348-52, 2007 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-17711742

RESUMO

BACKGROUND: Pancreatic cancer is one of the most common tumors and has a 5-year survival for all stages of less than 5%. Most patients with pancreatic cancer are diagnosed at an advanced stage and therefore are not candidates for surgical resection. In recent years, investigation into alternative treatment strategies for this aggressive disease has led to advances in the field of gene therapy for pancreatic cancer. E. coli purine nucleoside phosphorylase/6-methylpurine deoxyribose (ePNP/MePdR) is a suicide gene/prodrug system where PNP enzyme cleaves nontoxic MePdR into cytotoxic membrane-permeable compounds 6-methylpurine (MeP) with high bystander activity. hTERT is expressed in cell lines and tissues for telomerase activity. In this study we examined the efficacy of ePNP under the control of hTERT promoter sequences and assessed the selective killing effects of the ePNP/prodrug MePdR system on pancreatic tumors. METHODS: Recombinant pET-PNP was established. The protein of E. coli PNPase was expressed and an antibody to E. coli PNPase was prepared. Transcriptional activities of hTERT promoter sequences were analyzed using a luciferase reporter gene. A recombinant phTERT-ePNP vector was constructed. The ePNP/MePdR system affects SW1990 human pancreatic cancer cell lines in vitro. RESULTS: The hTERT promoter had high transcriptional activity and conferred specificity on cancer cell lines. The antibody to E. coli PNPase was demonstrated to be specific for the ePNP protein. The MePdR treatment induced a high in vitro cytotoxicity on the sole hTERT-ePNP-producing cell lines and affected SW1990 cells in a dose-dependent manner. CONCLUSIONS: The hTERT promoter control of the ePNP/MePdR system can provide a beneficial anti-tumor treatment in pancreatic cancer cell lines including a good bystander killing effect.


Assuntos
Escherichia coli/enzimologia , Terapia Genética , Neoplasias Pancreáticas/terapia , Regiões Promotoras Genéticas , Nucleosídeos de Purina/uso terapêutico , Purina-Núcleosídeo Fosforilase/genética , Telomerase/genética , Linhagem Celular Tumoral , Humanos
6.
World J Gastroenterol ; 12(26): 4156-60, 2006 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-16830364

RESUMO

AIM: To investigate the role of IFN-gamma inducible protein -10 (IP-10) and regulated upon activation, normal T cell expressed and secreted (RANTES) protein in acute pancreatic allograft rejection in rats. METHODS: An experimental pancreas transplantation model was established using diabetic SD rats as the recipient, induced by applying streptozocin (STZ). Pancreas transplantation was performed with a physiologic method of portal venous and enteric drainage. Rats were divided into two groups, isograft group (group A, n = 24) and allograft group (group B, n = 24) in which either healthy SD rats or Wistar rats served as donors, respectively. Twelve diabetic or healthy SD rats were used as controls. At d 1, 4, 7, and 10 post transplantation, serum IP-10 and RANTES were assessed by ELISA and their expression in the allografts was determined by immunohistochemistry. RESULTS: In group B (allograft group), the development of acute rejection was significantly correlated with increased serum concentration and tissue expression of IP-10 and RANTES, with a peak level at d 7 post transplantation. In contrast, there was no obvious change before and after transplantation in group A (isograft group). CONCLUSION: Our study suggests a possible role of IP-10 and RANTES in acute rejection and early monitoring of chemokines may be helpful in predicting the outcome of pancreas transplantation.


Assuntos
Quimiocina CCL5/metabolismo , Quimiocinas CXC/metabolismo , Regulação da Expressão Gênica , Rejeição de Enxerto/metabolismo , Transplante de Pâncreas/patologia , Animais , Quimiocina CCL5/genética , Quimiocina CXCL10 , Quimiocinas/metabolismo , Quimiocinas CXC/genética , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Rejeição de Enxerto/etiologia , Rejeição de Enxerto/genética , Sobrevivência de Enxerto , Masculino , Pâncreas/metabolismo , Pâncreas/patologia , Ratos , Ratos Sprague-Dawley , Ratos Wistar
7.
World J Gastroenterol ; 12(1): 36-42, 2006 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-16440414

RESUMO

AIM: To detect the expression of CD44 correlated with the ability of micro-metastasis in peripheral blood and bone marrow of patients with gastric cancer and to deduce its clinical significance. METHODS: Preoperative peripheral blood and bone marrow specimens from 46 patients with gastric cancer and 6 controls were studied by semi-quantitative RT-PCR amplification of CD44v6mRNA. Preoperative and postoperative peripheral blood specimens from 40 patients with gastric cancer and 14 controls were studied by quantitative RT-PCR amplification of CD44v6mRNA in the corresponding period. RESULTS: Semi-quantitative RT-PCR amplification showed that CD44v6mRNA expression of peripheral blood and bone marrow was positive in 39 (84.8%) and 40 (86.9%) of 46 patients with gastric cancer, respectively. In peripheral blood, CD44v6mRNA expression was positive for diffuse type in 30 (93.8%) of 32 patients and for intestinal type in 9 (64.3%) of 14 patients. On the other hand, in bone marrow, CD44v6mRNA expression was positive for diffuse type in 31 (96.9%) of 32 patients and for intestinal type in 10 (71.4%) of 14 patients. There was a significant difference between the diffuse type and intestinal type. Quantitative RT-PCR amplification demonstrated that CD44v6mRNA was not expressed in the peripheral blood of controls and CD44v6mRNA expression was positive for preoperative peripheral blood in 40 patients with gastric cancer, the expression levels being from 4.9 x 10(8) - 3.2 x 10(11) copies/g RNA. The average expression level of CD44v6mRNA in peripheral blood was 3.9 x 10(10) copies/g RNA. The expression levels of CD44v6mRNA in peripheral blood in gastric cancer patients after curative operation increased from 5.5 x 10(6) to 7.6 x 10(9) copies/g RNA and the average level was 2.4 x 10(8) copies/g RNA (Figure 3B) (P = 0.00496). After curative operation, the expression level decreased markedly. CONCLUSION: Semi-quantitative and quantitative RT-PCR amplification for CD44v6mRNA is a sensitive and specific method for the detection of micro-metastasis in peripheral blood and bone marrow, which might be used as an indicator of tumor burden and therapeutic effect.


Assuntos
Medula Óssea/metabolismo , Glicoproteínas/genética , Receptores de Hialuronatos/genética , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Calibragem , Feminino , Glicoproteínas/sangue , Humanos , Receptores de Hialuronatos/sangue , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa
8.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 27(5): 572-4, 2005 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-16274034

RESUMO

OBJECTIVE: To investigate the feasibility and therapeutic results of multiple organ resection in patients with tumor of the body and tail of pancreas. METHODS: The clinical and pathological data were analysed in 16 consecutive patients with neoplasm of the body and tail of pancreas from 1999 to 2004 retrospectively. RESULTS: Multiple organ resection was performed in 6 cases of primary pancreatic adenocarcinoma of the body and tail (3 cases of pancreatic cancer, 2 cases of malignant glucagonoma, and 1 case of well-differentiated pancreatic stromal sarcoma) and 10 cases of extrapancreatic malignancy (4 cases of gastric cancer, 2 cases of gastric leiomyosarcoma, 1 case of duodenal cancer, and 3 cases of colon cancer of hepatic flexure). Distal pancreatectomy with splenectomy was performed in all cases. In addition, 10 patients received splenic flexure colectomy, 6 patients received distal gastrectomy, 3 patients received left nephrectomy, left colectomy, total gastrectomy, liver lobe resection, left adrenalectomy, and local diaphragma resection, and 2 patients received transverse colectomy, subtotal colectomy, proximal proctectomy, proximal gastrectomy, and duodenectomy. No perioperative death and severe complications were observed. Patients with primary pancreatic cancer or pancreatic stromal sarcoma died within 1 year. Two patients with malignant glucagonoma died 51 and 39 months later. The 3-year survival rate was 70% in 10 patients with extrapancreatic malignancy, among which 2 patients with enteric cancer have survived 37 and 48 months. CONCLUSION: Radical combined multiple organ resection may be performed actively in appropriately selected patients.


Assuntos
Adenocarcinoma/cirurgia , Pancreatectomia/métodos , Neoplasias Pancreáticas/cirurgia , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Adulto , Idoso , Colectomia , Feminino , Gastrectomia , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/mortalidade , Neoplasias Pancreáticas/patologia , Pancreaticoduodenectomia , Estudos Retrospectivos , Esplenectomia , Taxa de Sobrevida , Resultado do Tratamento
9.
Hepatobiliary Pancreat Dis Int ; 1(4): 495-8, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14607674

RESUMO

OBJECTIVE: To study the markers of early rejection and pathological changes in simultaneous pancreaticoduodenal and kidney transplantation (SPKT). METHODS: Thirty hybrid pigs were used as donors and recipients. A renoportal end-to-end anastomosis between the left renal vein and the distal end of the portal vein was performed. Two vascular end-to-side anastomoses between the donor portal vein and recipient inferior vena cava, and between the donor aortic segment including the celiac and superior mesenteric, and left renal arteries and recipient abdominal aorta were carried out. Pancreas exocrine secretion drainage was established with duodenocystostomy. Ureterostomosis of the graft was performed. Urine amylase level, fasting blood glucose and urine volumes of kidney allograft were monitored, and pathological changes of graft were observed. RESULTS: Of 15 recipients, 2 died of disturbance of internal environment and anastomotic bleeding, respectively. Satisfactory results were obtained in the remaining 13 recipients. The changes of urine amylase concentration were prior to those of fasting blood glucose and urine volumes of kidney allograft. The degree of rejection of the kidney allograft was more severe than that of the pancreas and duodenum allograft. CONCLUSIONS: Urine amylase is the early marker of acute rejection in SPKT with bladder drainage of pancreatic exocrine secretion. The pathological change of kidney allograft is most significant in SPKT.


Assuntos
Duodeno/transplante , Rejeição de Enxerto/patologia , Transplante de Rim , Transplante de Pâncreas , Amilases/urina , Animais , Glicemia/metabolismo , Duodeno/patologia , Jejum/sangue , Feminino , Sobrevivência de Enxerto , Rim/patologia , Masculino , Necrose , Pâncreas/patologia , Suínos , Fatores de Tempo , Transplante Homólogo , Urodinâmica
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