RESUMO
Objective: To investigate the value of myocardium scar area in predicting adverse cardiovascular events (MACEs) after coronary artery bypass grafting (CABG) in patients with ischemic cardiomyopathy (ICM). Methods: The first part of this study was a retrospective study. Patients diagnosed with ICM and undergoing CABG surgery at Beijing Anzhen Hospital, Capital Medical University from January 2017 to December 2022 were enrolled as the discovery cohort. All patients underwent cardiac magnetic resonance-late gadolinium enhancement (CMR-LGE) before surgery. According to the occurrence of postoperative MACEs, the patients were divided into MACEs group and MACEs-free group. Preoperative clinical and imaging data, intraoperative and postoperative data were collected and compared between the two groups. The primary endpoint was postoperative MACEs. Univariate and multifactor regression analyses were used to analyze the risk factors for MACEs. Receiver operating characteristic (ROC) curves were constructed to evaluate the predictive efficacy and optimal cut-off value of myocardial scar area for endpoint events. The second part of this study was a prospective study. Patients with ICM who received CABG at Beijing Anzhen Hospital, Capital Medical University from January 2023 to June 2023 were enrolled as a validation cohort, and were divided into MACEs group and MACEs-free group according to whether MACEs occurred after surgery. Preoperative clinical and imaging data, intraoperative and postoperative data were collected and compared between the two groups. Verify the reliability of the cut-off value obtained by ROC curve in the validation cohort. Results: A total of 120 patients with ICM (30 patients in MACEs group and 90 patients in MACEs-free group), aged (61.6±8.7) years, including 93 males, were included in the discovery cohort. A total of 22 ICM patients (5 patients in MACEs group and 17 patients in MACEs-free group), aged (59.5±8.2) years, including 18 males, were included in the validation cohort. Multivariate Cox regression showed that myocardial scar area (HR=1.258, 95%CI 1.096-1.444, P=0.001) was an independent risk factor for the primary endpoint event. The area under ROC curve of myocardial scar area for predicting postoperative MACEs was 0.90 (95%CI 0.83-0.95), and myocardial scar area≥36.0% was the optimal cut-off value for predicting postoperative MACEs, and its sensitivity, specificity and accuracy were 96.7%, 72.2% and 78.3%, respectively. In the validation cohort, the sensitivity, specificity and accuracy of myocardial scar area in predicting postoperative MACEs in patients with ICM after CABG were 80.0%, 82.4% and 81.8%, respectively. Conclusion: Myocardial scar area is an independent risk factor for MACEs after CABG in patients with ICM, and myocardial scar area≥36.0% is the optimal cut-off value for predicting MACEs after CABG. Myocardial scar area can help to identify patients at high risk of surgery and provide a basis for risk stratification of patients.
Assuntos
Cardiomiopatias , Cicatriz , Ponte de Artéria Coronária , Isquemia Miocárdica , Humanos , Ponte de Artéria Coronária/efeitos adversos , Ponte de Artéria Coronária/métodos , Estudos Retrospectivos , Isquemia Miocárdica/etiologia , Cicatriz/etiologia , Cardiomiopatias/etiologia , Fatores de Risco , Feminino , Masculino , Estudos Prospectivos , Complicações Pós-Operatórias/etiologia , Curva ROC , Pessoa de Meia-Idade , Miocárdio/patologiaRESUMO
Objective: To in vestigate the death-related risk factors of surgical treatment of myocardial infarction (MI) combined with ventricular septal rupture (VSR). Methods: The clinical data of patients (68 cases) with ventricular septal rupture after myocardial infarction (PI-VSR) from January 2008 to December 2020 in Beijing Anzhen Hospital were retrospectively selected and analyzed. We followed up the surviving patients and divided them into the survival group and the death group according to the perioperative and follow-up results. The univariate analysis was performed on various indicators, and the Cox regression analysis was used to analyze the risk factors related to postoperative death. Results: A total of 68 patients (42 were male and 26 were female, with age 44-82 (64.3±8.2) years after surgical treatment of myocardial infarction combined with ventricular septal rupture were enrolled, 9 patients died during the perioperative period, 59 surviving patients were followed up for 0.1-10.5 years(mean, 4 years), and 7 deaths during follow-up. Based on this, 52 patients were selected as the survival group while 16 patients as the death group. The results of univariate analysis showed that age, VSR to operation time less than 7 days, killip grade ≥ grade 3, cardiogenic shock, preoperative use of IABP, emergent surgery were related to postoperative death. The factors with P<0.2 factors in univariate analysis were selected into the multivariate Cox regression analysis. Age ([OR=1.110(1.012-1.217), P=0.026], platelet count [OR=0.990(0.981-0.999), P=0.031], D dimer (OR=1.002[1.001-1.003], P=0.003), cardiogenic shock (OR=6.084[1.729-21.405], P=0.005) were independent risk factors for postoperative death. All patients were followed up, the survival rate of 2-year, 4-year, 6-year, 8-year, and 10-year was 77.5%, 77.5%, 71.0%, 71.0%, and 71.0%, respectively. Conclusions: Age, platelet count, D-dimer, and cardiogenic shock are risk factors for death after surgical treatment of myocardial infarction combined with ventricular septal rupture. Surgery is an effective method for the treatment of myocardial infarction combined with ventricular septal rupture. Long-term prognosis of the surviving patients during perioperative are relatively better.
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Infarto do Miocárdio , Ruptura do Septo Ventricular , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Choque Cardiogênico , Resultado do Tratamento , Ruptura do Septo Ventricular/etiologia , Ruptura do Septo Ventricular/cirurgiaAssuntos
Corantes Fluorescentes , Verde de Indocianina , Protectomia , Neoplasias Retais , Fluorescência , Corantes Fluorescentes/administração & dosagem , Humanos , Verde de Indocianina/administração & dosagem , Protectomia/instrumentação , Protectomia/métodos , Proctoscopia , Neoplasias Retais/diagnóstico , Neoplasias Retais/cirurgia , Reto/patologia , Reto/cirurgiaRESUMO
The incidence of adenocarcinoma of the esophagogastric junction (AEG) continues to rise. While many treatment modalities are available, surgery is still the basis of comprehensive treatment of AEG. Siewert type II AEG, is more controversial than the other two types in terms of lymph node metastasis, surgical approach, extent of resection, and digestive tract reconstruction. When the distance of the superior tumor margin is more than 3 cm proximal to the EGJ line is more than 3 cm, thorough mediastinal lymph node dissection should be performed through thoracic approach. Total gastrectomy is the treatment of choice for Siewert type II tumors. When the tumor stage is in an early stage, the length of the tumor is ≤4 cm, and esophageal involvement is less than 3 cm, transthoracic esophagectomy plus proximal gastrectomy is feasible. The digestive tract reconstruction can be based on the experience of the operator and patient's choice of conditions.
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Adenocarcinoma , Neoplasias Esofágicas , Junção Esofagogástrica , Neoplasias Gástricas , Adenocarcinoma/cirurgia , Neoplasias Esofágicas/cirurgia , Esofagectomia , Junção Esofagogástrica/cirurgia , Gastrectomia , Humanos , Neoplasias Gástricas/cirurgiaRESUMO
Objective: To explore the safety and feasibility of indocyanine green (ICG) injection through accessory incision in laparoscopic right hemicolectomy. Methods: A descriptive case series study was carried out. Clinicopathological data of 29 patients with colon cancer undergoing right hemicolectomy at Department of General Surgery, Guangdong Provincial People's Hospital were retrospectively analyzed. All the patients received ICG injection through accessory incision at the beginning of operation. Results: Among 29 patients, 13 were male and 16 were female with a mean age of (60.8±7.7) years and mean body mass index of (24.3±2.8) kg/m(2); 3 were stage I, 19 were stage II, 7 were stage III. Pericolic, intermediate and main lymph nodes could be detected under near infrared fluorescence imaging (NIRFI) in all the cases. No.6 lymph nodes were observed in 3 cases, while no lymph nodes around superior mesenteric vein (SMV) were found. The average number of fluorescent lymph node was 14.2±6.1. The average developing time of fluorescence was (36.2±3.7) minutes. The average number of harvested lymph nodes was 22.4±8.2. There was no extravasation of imaging agent during the operation, and there were no intraoperative complications such as allergies, massive abdominal bleeding, peripheral organ damage, etc. Operative time was (113.1±10.7) minutes, blood loss during operation was (22.4±3.9) ml, ambulatory time was (1.2±0.4) days, time to the first flatus was (1.7±0.7) days, time to the first fluid diet was (0.7±0.4) days, and postoperative hospital stay was (5.8±1.5) days. No operation-associated complications such as anastomotic bleeding, anastomotic leakage, peritoneal bleeding, peritoneal infection, incision infection occurred after operation. Conclusion: ICG injection through accessory incision in laparoscopic right hemicolectomy is safe and feasible.
Assuntos
Neoplasias do Colo , Laparoscopia , Idoso , Colectomia , Neoplasias do Colo/cirurgia , Estudos de Viabilidade , Feminino , Humanos , Verde de Indocianina , Excisão de Linfonodo , Masculino , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
BACKGROUND: Prostate volume (PV) and its change rate are important for the progression of prostate disease, but studies on their estimates are inconsistent. OBJECTIVES: To investigate whether age, prostate-specific antigen (PSA), and other specific characteristics are associated with PV and its change rate. MATERIALS AND METHODS: A community-based cohort study was conducted in a rural area of China among male residents aged 40-80 years. PV was estimated at baseline and at 4 years of follow-up by trans-abdominal ultrasound. Annual PV change rate (PVCR) was calculated as change in volume divided by time interval. Baseline characteristics, including age, serum PSA, and hormones, were evaluated. And their relationships with PV or PVCR were assessed with Pearson correlation and multivariate linear regression analyses. RESULTS: Totally, 462 participants completed the follow-up with baseline PV (PV0 ) of 15.6 ± 5.5 ml. PV0 was highly correlated with age and PSA in pairwise correlations (Pearson r = 0.35 and 0.34, respectively, p < 0.01). Multivariate linear regression showed similar associations that PV0 tended to increase with age and PSA. The average PVCR was 0.7 ± 1.8 ml/year. In pairwise correlations, PVCR was inversely correlated with PV0 and positively correlated with PSA, while it was not significantly related to baseline age. Linear regression of PVCR on age and PSA in groups classified by PV0 quartile showed that age was not a significant estimator of PVCR, whereas PSA was. In each PV0 group, PVCR tended to increase with PSA. DISCUSSION AND CONCLUSION: PV was positively associated with age and PSA, and it tended to grow faster in men with smaller baseline PV and higher PSA. PSA can be a valuable parameter for estimating both the size and the growth speed of prostate. Although age is associated with prostate enlargement, it does not appear to be related to the longitudinal change rate of PV.
Assuntos
Antígeno Prostático Específico/sangue , Próstata/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Estudos de Coortes , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do ÓrgãoRESUMO
Objective: To investigate the feasibility and safety of the medial approach "four-step method" in the laparoscopic mobilization of splenic flexure. Methods: A retrospective cohort study was performed. Clinical data of 157 colorectal cancer patients undergoing the medial approach "four-step method" in the laparoscopic mobilization of splenic flexure at Gastrointestinal Surgical Department of Guangdong Provincial People's Hospital from July 2015 to June 2018 were retrospectively analyzed. Of 157 cases, 17 were transverse colon cancer, 94 were descending colon cancer, 25 were sigmoid cancer and 21 were rectal cancer; 89 were male and 68 were female; mean age was (61.8±10.3) years and mean body mass index was (23.2±3.7) kg/m(2). The medial approach "four-step method" in the laparoscopic mobilization of splenic flexure was performed as follows: (1) The root vessels were treated with the "provocation" technique to expand the Toldt's gap. This expansion was extended from the lateral side to the peritoneum reflex of left colonic sulcus, from the caudal side to the posterior rectal space, and from the cephalad side to the lower edge of pancreas. (2) The left colonic sulcus was mobilized, converging with the posterior Toldt's gap. Mobilization was carried out from cephalad side to descending colon flexure, freeing and cutting phrenicocolic ligament and splenocolic ligament, and from caudal side to peritoneal reflex. (3) Gastrocolic ligament was moblized. Whether to enter the great curvature of stomach omentum arch when the gastrocolic ligament was cut, that was, whether to clean the fourth group of lymph nodes, should be according to the tumor site and whether serosal layer was invaded. (4) Transverse mesocolon was moblized and transected at the lower edge of the pancreatic surface, merging with the posterior Toldt's gap, and from lateral side to lower edge of the pancreatic body, merging with the lateral left paracolonic sulcus. Safety and short-term clinical efficacy of this surgical procedure was summarized. Results: All the patients completed this procedure. During operation, 3 cases were complicated with organ injury, including 1 case of colon injury, 1 case of spleen injury and 1 case of pancreas injury. No operative death and conversion to open surgery was found. The average operation time was (147.5±35.1) minutes, the average intra-operative blood loss was (40.8±32.7) ml and the average number of harvested lymph node was (16.1±5.8), including (4.0±2.3) of positive lymph nodes. The first exhaust time after surgery was (41.3±20.6) hours, the fluid intake time was (1.5±1.3) days, the postoperative hospital stay was (5.2±2.3) days. Eight (5.1%) cases developed postoperative complications, and all were improved and discharged after conservative treatments. According to the TNM classification system, postoperative pathology revealed that 31 patients were stage I, 51 were stage II, 53 were stage III, 22 were stage IV. Conclusion: The medial approach "four-step method" is safe and feasible, which can effectively decrease the operation difficulty of the laparoscopic mobilization of the splenic flexure.
Assuntos
Colectomia/métodos , Colo Transverso/cirurgia , Neoplasias do Colo/cirurgia , Laparoscopia/métodos , Neoplasias Retais/cirurgia , Idoso , Anastomose Cirúrgica , Estudos de Viabilidade , Feminino , Humanos , Masculino , Mesentério/cirurgia , Pessoa de Meia-Idade , Peritônio/cirurgia , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Objective: To evaluated early clinical outcomes of saphenous vein grafts harvested with a No-touch technique in off-pump coronary artery bypass graft (OPCABG) surgery. Methods: A total of 124 patients with three-vessel disease undergoing OPCABG by No-touch technique between June and November 2017 in Beijing An Zhen Hospital were respectively reviewed. Results: The average age of patients was (60.7±10.3) years, and 80 cases (64.5%) were male, with the average body mass index (BMI)of (25.4±2.5) kg/m(2,) the mean preoperative left ventricular ejection fraction (LVEF) of (58.0±7.0%). The operative time was (4.0±0.4) hours, and 16 cases (12.9%) were harvested for whole vein grafts. The number of vein grafts and venous anastomoses was 144 and 284, respectively. There were 16 cases of single bridge NTSVG-LAD, 4 cases of single bridge NTSVG-D, 99 cases of sequential bridge NTSVG-OM-PDA, 5 cases of sequential bridge NTSVG-OM-PLV, 4 cases of sequential bridge NTSVG-OM-RCA, 16 cases of sequential bridge NTSVG-D-OM-PDA. The mean flow volume of No-touch vein grafts was (51.9±2.4) ml/min. There was no death case in hospital. Postoperative re-exploration for hemorrhage of anastomosis happened in 1 case (0.8%), which was caused by pericardial tamponade due to insufficiency of hemostasis in internal mammary bed. There were 1 case of bad wound healing of lower extremity incision (0.8%). A total of 124 cases were followed up after operation, and the follow-up rate was 100%. There was one all-cause death (0.8%) 27 days after the operation. Conclusion: The short-term clinical observation of the application of No-touch great saphenous vein harvesting technique for OPCABG is safe and effective.
Assuntos
Veia Safena , Idoso , Anastomose Cirúrgica , Ponte de Artéria Coronária , Ponte de Artéria Coronária sem Circulação Extracorpórea , Feminino , Veia Femoral , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Grau de Desobstrução VascularRESUMO
Loss of Ras association domain family protein 1 isoform A (RASSF1A) expression is associated with the development of a variety of human cancers and the expression of carcinoembryonic antigen (CEA) frequently occurs in gastric cancer. This study investigated the effects of RASSF1A expression restoration using a hypoxia-inducible CEA promoter-driven vector on xenograft tumor growth in nude mice and on the in-vitro regulation of gastric cancer cell viability, cell cycle distribution, apoptosis, colony formation and invasion capacity. The data showed that the level of CEA mRNA and protein was much higher in gastric cancer SGC7901 cells than in a second gastric cancer cell line, MKN28, or in the MCF-10A normal epithelial breast cell line. RASSF1A expression was restored in SGC7901 cells compared with the negative control virus-infected SGC7910 cells. RASSF1A expression restoration significantly inhibited gastric cancer cell viability, colony formation and invasion capacity, but induced cell cycle arrest and apoptosis in vitro, especially under hypoxic culture conditions. At the gene level, restoration of RASSF1A expression under hypoxic culture conditions significantly suppressed matrix metalloproteinase-2 expression and prevented cyclinD1 expression. A nude mouse xenograft assay showed that the restoration of RASSF1A expression reduced gastric cancer xenograft formation and growth. In conclusion, the restoration of RASSF1A expression using a hypoxia-inducible and CEA promoter-driven vector suppressed aggressive phenotypes of gastric cancer cells in vitro and in vivo. These results suggest that LV-5HRE-CEAp-RASSF1A gene therapy may be a promising novel approach to treat advanced gastric cancer.
Assuntos
Terapia Genética , Vetores Genéticos , Lentivirus , Neoplasias Gástricas/genética , Proteínas Supressoras de Tumor/genética , Animais , Linhagem Celular Tumoral , Proliferação de Células/genética , Sobrevivência Celular/genética , Regulação Neoplásica da Expressão Gênica , Xenoenxertos , Humanos , Camundongos , Camundongos Nus , Neoplasias Gástricas/patologia , Neoplasias Gástricas/terapia , Proteínas Supressoras de Tumor/biossínteseRESUMO
A nested genetic algorithm, including a genetic parameter level and a genetic implemented level, has been proposed and applied for resolving simulated overlapping spectra. Parameters of genetic algorithms (GA) were optimized by use of the genetic parameter level. The number of overlapping peaks was, moreover, detected simultaneously. Parameters of individual peaks in multiplets were computed by use of the genetic implemented level. It is obvious that the parameters of GA can be optimized and the number of overlapping peaks can be detected by itself. The optimization results are less affected than in traditional curve-fitting by the initial values of the parameters of the overlapping bands. Consequently, the nested genetic algorithm is superior to the curve-fitting technique for resolution of overlapping peaks.
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Algoritmos , Processamento de Sinais Assistido por Computador , Análise Espectral/métodosRESUMO
The beta-amyloid precursor protein (APP) is a ubiquitous receptor-like molecule without a known function. However, the recent recognition that APP and Notch undergo highly similar proteolytic processing has suggested a potential signaling function for APP. After ligand binding, Notch is cleaved by the ADAM-17 metalloprotease followed by an intramembrane cleavage mediated by gamma-secretase. The gamma-secretase cut releases the Notch intracellular domain (NICD), which enters the nucleus and modulates transcription. Because APP is processed similarly by ADAM-17 and gamma-secretase, we reasoned that the APP intracellular domain (AICD) has a role analogous to the NICD. We therefore generated a plasmid encoding the AICD sequence and studied the subcellular localization of the expressed protein (C60). Our results demonstrate that the cytoplasmic domain of APP is a highly labile fragment that is stabilized by forming complexes with Fe65 and can then enter the nucleus in neurons and non-neural cells. These findings strongly support the hypothesis that APP signals in the nucleus in a manner analogous to the function of Notch.
Assuntos
Transporte Ativo do Núcleo Celular , Precursor de Proteína beta-Amiloide/metabolismo , Proteínas de Drosophila , Proteínas do Tecido Nervoso/metabolismo , Proteínas Nucleares/metabolismo , Fragmentos de Peptídeos/metabolismo , Proteínas ADAM , Proteína ADAM17 , Secretases da Proteína Precursora do Amiloide , Ácido Aspártico Endopeptidases , Proteína de Ligação a CREB , Endopeptidases/metabolismo , Meia-Vida , Proteínas de Membrana/metabolismo , Metaloendopeptidases/metabolismo , Ligação Proteica , Processamento de Proteína Pós-Traducional , Receptores Notch , Proteínas Repressoras/metabolismo , Transdução de Sinais , Transativadores/metabolismoRESUMO
PAX6 is a transcription factor that plays a major role in ocular morphogenesis. PAX6 is expressed in the eye, central nervous system and pancreas. Two alternative promoters, P0 and P1, which are differentially regulated during development, drive PAX6 transcription. We identified a 57 bp cis-regulatory element in exon 1 of the human PAX6 gene exon 1 enhancer (EIE). EIE enhances P1-driven PAX6 expression. Three regions in E1E (E1E-1, E1E-2 and E1E-3) have sequence similarities with binding sites of transcription factors ARP-1, Isl-1 and SEF, respectively. As shown by electrophoretic mobility shift assays, E1E-3, but not E1E-1 or E1E-2, bound to proteins in nuclear extracts of human glioma cells and transcription factor SEF bound to E1E-3. As shown by transient transfection experiments, deletion or site-specific mutations in E1E-3 dramatically decreased P1 promoter activity. Mutations in E1E-2, however, did not affect function of the P1 promoter. Co-transfection of SEF and PAX6 promoter-reporter constructs showed that SEF up-regulates PAX6 gene expression through the P1 promoter. Two Sp1 sites in the E1E region were also shown to be important by transient co-transfection assays. Data from immunoprecipitation and transient transfection assays demonstrated that SEF and Sp1 interacted in vitro and may act together in vivo to regulate PAX6 expression.
Assuntos
Proteínas de Ligação a DNA/fisiologia , Elementos Facilitadores Genéticos , Proteínas de Homeodomínio/genética , Fator de Transcrição Sp1/fisiologia , Fatores de Transcrição/fisiologia , Sequência de Bases , Sítios de Ligação , Extratos Celulares , Núcleo Celular/metabolismo , Éxons , Proteínas do Olho , Genes Reporter , Humanos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Fator de Transcrição PAX6 , Fatores de Transcrição Box Pareados , Regiões Promotoras Genéticas , Proteínas de Ligação a RNA , Proteínas Repressoras , Ativação Transcricional , Células Tumorais CultivadasRESUMO
The emission spectra from the pulsed discharge plasma of nitrogen, ammonia or their mixture were measured. In the discharge of pure nitrogen gas, as the pressure increased, the discharge volume decreased and more dissociation of nitrogen molecules occurred due to the higher energy density. In the discharge of ammonia, N,N+ and NH+ were observed, but no NH2 and NH3 were detected, indicating that ammonia, which has the lower dissociation and ionization energies as compared to nitrogen, was highly dissociated. The discharge of the mixture of N2 and NH3 was also studied. The dependence of the dissociation of nitrogen on the ratio of nitrogen to ammonia was investigated by emission spectra. The optimal ratio for nitrogen dissociation was obtained. The advantage of using the mixture of nitrogen and ammonia in the synthesis of nitrides was discussed.
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Amônia/química , Eletricidade , Nitrogênio/química , Fenômenos Químicos , Físico-Química , Íons , Pressão , Processamento de Sinais Assistido por Computador , Análise Espectral/métodosRESUMO
Pax-6 encodes a transcription factor that is important in the development of eye and CNS. Identification of Pax-6 target genes is crucial for understanding the gene regulatory network in these developmental processes. Using an in-vitro approach of cyclic amplification of the protein binding sequences (CAPBS), we isolated a PAX6 binding sequence from a human single-copy (sc) DNA library. Characterization of this PAX6 binding sequence revealed a 15bp region (hGCalpha1BLs5) that is sufficient for PAX6 specific binding. From a homology search in the GenBank, we found that an hGCalpha1BLs5-like Pax-6 binding site exists in 21 genes (16 from rodent), 15 of which were shown to be able to bind Pax-6 in vitro. Interestingly, some of these sites occur in B1 repetitive elements. Although hGCalpha1BLs5 is highly similar to a region in B1 repetitive elements, PAX6 does not bind to the consensus sequence in B1. However, a single-step mutation in some B1 elements can lead to a gain of function for PAX6 binding. This experimental evidence and phylogenetic analysis raise an interesting speculation for the coevolution between PAX6 regulation and repeat elements. Since a (Pax-6-binding) null B1 element can be re-activated by even a single-step mutation, it has the potential to recruit gene targets for Pax-6 if it is inserted into the regulatory region, and therefore may play a role for evolutionary modification of Pax-6 regulation.
Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Homeodomínio , Sequências Repetitivas de Ácido Nucleico/genética , Animais , Sequência de Bases , Sítios de Ligação/genética , Ligação Competitiva , DNA/química , DNA/genética , Proteínas de Ligação a DNA/metabolismo , Eletroforese em Gel de Poliacrilamida , Evolução Molecular , Proteínas do Olho , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Células K562 , Camundongos , Dados de Sequência Molecular , Mutação , Oligonucleotídeos/síntese química , Oligonucleotídeos/metabolismo , Fator de Transcrição PAX6 , Fatores de Transcrição Box Pareados , Filogenia , Ligação Proteica , Proteínas Repressoras , Roedores , Análise de Sequência de DNA , Homologia de Sequência do Ácido NucleicoRESUMO
We have used the UvrABC nuclease incision method in combination with ligation-mediated polymerase chain reaction (LMPCR) techniques to map and quantify (+/-)anti-7beta, 8alpha-dihydroxy-9alpha, 10alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]-pyrene (BPDE) adduct formation in the p53 gene of human cells. We found that BPDE adduct formation, as revealed by UvrABC incision, preferentially occurred at methylated CpG sites that correspond to the mutational hotspots observed in human lung cancers. Our hypothesis is that it is this methylated CpG sequence-dependent preferential adduct formation, rather than selective growth advantage, that is the major determinant of the p53 mutation pattern in human cancers. Given the far reaching ramifications of such conclusions for cancer etiology, a legitimate question is raised regarding the reliability of using the UvrABC incision method for quantifying and determining the sequence-dependency of adduct formation. Is the higher frequency of UvrABC cutting at methylated versus unmethylated CpG sites due to the preference of the nuclease for cutting at those sites or due to the preferential formation of BPDE adducts at those sites? In order to distinguish between these two possibilities, we have analyzed the kinetics of UvrABC incision at BPDE adducts formed at either methylated CpG sites versus other sequences, or unmethylated CpG sites versus other sequences in exon 5 of the p53 gene. We have found that the UvrABC cutting kinetics are identical for both cases. On the basis of these results we conclude that under proper cutting conditions, UvrABC nuclease reacts with and incises with equal efficiency, BPDE adducts formed at methylated or unmethylated CpG sites as well as other sequences, and that the extent of UvrABC incision accurately reflects the extent of BPDE-DNA adduct formation. These conclusions were further supported by results obtained using a DNA synthesis blockage assay.
Assuntos
7,8-Di-Hidro-7,8-Di-Hidroxibenzo(a)pireno 9,10-óxido/metabolismo , Ilhas de CpG , Adutos de DNA/metabolismo , Metilação de DNA , Endodesoxirribonucleases/metabolismo , Proteínas de Escherichia coli , Genes p53 , Sequência de Bases , Primers do DNA , Humanos , CinéticaRESUMO
1. In the retina, two distinct, light-evoked releases of K+ have been described. One takes place in the outer plexiform layer (OPL) and is termed the "distal K+ increase." The other takes place in the inner plexiform layer (IPL) and is termed the "proximal K+ increase." Although the distal K+ increase generates the electroretinogram (ERG) b-wave, the contribution of the much larger proximal K+ increase to the ERG is less well understood. In this paper we detail our investigation of the proximal K+ increase and its contribution to the ERG. We describe an ERG component, the M-wave, which had not heretofore been observed in the diffuse-flash, vitreal ERG. 2. We studied the proximal K+ increase and the ERG M-wave in the isolated retina preparation of the toad, Bufo marinus. We used K(+)-sensitive microelectrodes, as well as conventional intra- and extracellular microelectrodes, to record K+ changes, the local (or intraretinal) ERG, the vitreal ERG, and Müller cell responses. 3. As in earlier studies of the amphibian and cat M-wave, we readily observed an M-wave in the intraretinal, or local, ERG (LERG). The M-wave we studied had characteristics similar to those of M-waves that were previously described. Specifically, we found that the M-wave was generated by a Müller cell response to the proximal K+ increase and that both the proximal K+ increase and the LERG M-wave were spatially tuned. 4. We used the aspartate receptor agonist, N-methyl-DL-aspartate (NMA), to reveal that an M-wave is present in the vitreal ERG. Researchers who previously investigated the M-wave were unable to identify an M-wave in the vitreal ERG. We found that the toad ERG M-wave was a small, positive potential that was partially obscured by the much larger b-wave and slow PIII components. 5. We observed that picrotoxin (PTX) had an excitatory effect on inner retina, as evidenced by an enhanced proximal K+ increase and an enhanced M-wave. This result indicates that it is likely that GABAergic inhibition in inner retina plays an important role in retinal processing in the toad. 6. At threshold, we found that the ERG consisted mainly of an M-wave, indicating that the amphibian threshold ERG is driven by proximal retina. This result is analogous to previous observations of the threshold ERG in cat. However, in cat, the M-wave and threshold response have been described as distinct ERG components.(ABSTRACT TRUNCATED AT 400 WORDS)
Assuntos
Eletrorretinografia , Retina/fisiologia , Animais , Bufo marinus , Eletrorretinografia/efeitos dos fármacos , Eletrorretinografia/instrumentação , Técnicas In Vitro , Potenciais da Membrana , Microeletrodos , Estimulação Luminosa , Picrotoxina/farmacologia , Potássio/farmacologia , Retina/efeitos dos fármacos , Ácido gama-Aminobutírico/fisiologiaRESUMO
The temporally and spatially resolved transmission is measured with a green probe beam through the plasma created by an intense near-IR beam that is incident upon a water droplet. We report the propagation speed of the expanding plasma and the evolution of the transmission decrease and recovery at various locations along a line in the direction of the IR beam.
RESUMO
A questionnaire survey was conducted among 7,665 students and staff in the factory-operated industrial colleges in Shanghai, China. Response rate was 95.7 per cent. The proportion of smokers among the men was 50.5 per cent; only 0.33 per cent of the women reported they were smokers. Male smokers began smoking upon entering the work force, where social interaction encourages cigarette smoking. Seventy per cent of the male smokers smoked fewer than 10 cigarettes per day. Only 4.3 per cent perceived themselves as very addicted; 3.4 per cent reported they had no confidence in their ability to control the amount they smoke. The Chinese smokers are more likely to succeed in giving up cigarette smoking for at least one day, as well as for longer periods, compared to US smokers. The number of cigarettes smoked may be related to the individual's purchasing power. For China, strategic timeliness in legislative action and education is urgently needed to combat the high prevalence of cigarette smoking in males, at extremely high risk.
Assuntos
Educação em Saúde , Fumar/psicologia , Comportamento Social , Adulto , Atitude Frente a Saúde , China , Escolaridade , Feminino , Humanos , Masculino , Prevenção do Hábito de FumarRESUMO
An optical multichannel detection technique was used to measure simultaneously the time profiles of the input laser pulse and the elastic scattering, as well as the time profiles of the spectrally resolved multiorder stimulated Raman scattering (SRS), from single droplets. The time delay between the multiorder SRS and the input laser pulse is consistent with the generalized four-wave mixing process for first-order stimulated Raman growth, starting from spontaneous noise or the parametric signal. The presence of an internal plasma associated with laser-induced breakdown within a droplet quenches the SRS and increases the elastic scattering.