Biomedical subjects

Bin Lu

Publications and source records attributed to Bin Lu.

At least 73 records · Page 4Linked to original sources

PubMed2004

[Human recombinant interferon-alpha 2a polybutylcyanoacrylate sustained release lyophilized nanospheres for liver-targeting].

OBJECTIVE: To evaluate the liver-targeted and sustained release characteristics of human recombinant interferan-alpha 2a polybutylcyanoacrylate lyophilized nanospheres (rIFN alpha 2a-PBCA-NS). METHODS: Emulsification/polymerization method was used to prepare the nanospheres which was lyophilized to obtain rIFN alpha 2a-PBCA-NS, and cell pathological embarrassment (CPE) was used to determine the rIFN alpha 2a concentration in the preparations and biological samples. The in vivo distribution and pharmacokinetics in liver after intravenous injection (i.v.) of rIFN alpha 2a-PBCA-NS and rIFN alpha 2a in mice were evaluated. RESULTS: The rate of entrapment of the nanospheres was (56.2 +/- 4.3)%; the particle diameter, span of rIFN alpha 2a-PBCA-NS were (108 +/- 37) nm and 0.55, respectively, and their biological activity had little change after being stored at 3-5 degrees C for 6 months. The distribution ratio of rIFN alpha 2a after i.v. in mice liver increased from 13.1% (for rIFN alpha 2a) to 50.6% (for rIFN alpha 2a-PBCA-NS), and the mean retain time from 1.41 h (for rIFN alpha 2a) to 8.35 h (for rIFN alpha 2a-PBCA-NS). Of the distribution parameters (te for rIFN alpha 2a, re and te for rIFN alpha 2a-PBCA-NS) in 5 main organs, the largest ones were in liver and both re and te for rIFN alpha 2a-PBCA-NS in liver larger than one. CONCLUSION: The rIFN alpha 2a-PBCA-NS showed obviously liver-targeting and sustained release characteristics.

Animals↗

PubMed2004

Enhancement of naked FIX minigene expression by chloroquine in mice.

AIM: To study the effect of chloroquine on the expression of human clotting factor IX (hFIX) in mice. METHODS: Hydrodynamics-based naked DNA plasmid administration was performed by tail vein injection of 10 microg of pCMV- hFIX and chloroquine (0, 100, 200, and 500 micromol/L) in 2.2 mL of Ringer's solution within 6-7 s, the level and stability of hFIX expression, liver damage and toxicity were then examined. RESULTS: The maximum expression of hFIX level was 4.4+/-1.8 mg/L at 8 h after injection, 9.7+/-1.6 mg/L at 24 h only existed in 200 micromol/L chloroquine-treated animals, which is 3-4 fold higher than that of control (P<0.01). There is no significant difference observed among all the treated groups, 3 d later. Transaminase level and liver histological study showed the damage of liver was not related to chloroquine (P>0.05). CONCLUSION: Chloroquine can enhance and sustain exogenous gene expression in vivo without side effect under our experimental conditions.

Alanine Transaminase↗

PubMed2004

[Prevalence of dental anxiety in 144 patients with cardiovascular diseases before tooth extraction].

OBJECTIVE: To determine the prevalence of dental anxiety (DA) in patients with cardiovascular diseases before tooth extraction so as to provide psychotherapy. METHODS: 144 patients with cardiovascular diseases were asked to complete a questionnaire modified from Corah Dental Anxiety Scale (DAS) while awaiting for tooth extraction. RESULTS: The incidence rate of DA in these patients was 7.6%. Anxiety level on anesthesia procedure was the highest. DAS score was higher among patients with the following factors: inactive perception, female, below 60 years old, experiences of painful tooth extraction, a documented history of single cardiovascular disease, under ECG monitoring for the first time and complicated tooth extraction. CONCLUSION: DA existed in patients with cardiovascular diseases before tooth extraction and was related to many factors. Medical staff should take necessary measures to provide them with psychotherapy and nursing guidance before tooth extraction.

Adult↗

PubMed2003

Cyclooxygenase-2 expression in squamous dysplasia and squamous cell carcinoma of the esophagus.

Cyclooxygenase-2 (cox-2) overexpression has been observed in several types of human cancers and has been implicated in carcinogenesis. To elucidate the role of cox-2 in esophageal carcinogenesis, we evaluated the expression of cox-2 in normal squamous epithelium squamous epithelial dysplasia (n=47), and squamous cell carcinoma of the esophagus (n=86) by immunohistochemistry, reverse transcription-PCR assay, and western blotting. A significant overexpression of cox-2 was observed in esophageal squamous dysplasia and squamous cell carcinoma compared with normal squamous epithelium. The immunoreactive score of cox-2 expression, an index determined by intensity and positivity of cox-2 staining, was 0.71 +/- 0.46 (mean +/- SD) in normal squamous esophagus, 2.19 +/- 1.79 in squamous epithelial dysplasia, and 2.67 +/- 1.77 in squamous cell carcinoma. The results of immunohistochemistry were confirmed by a reverse transcription-PCR assay and western blotting analysis. Cox-2 expression level was correlated with proliferation activity assessed by proliferating cell nuclear antigen (PCNA) index and MIB-1 index in dysplastic lesion (r=0.55, P<0.01 with PCNA and r=0.72, P<0.01 with MIB-1) and carcinoma (r=0.56, P<0.01 with PCNA and r=0.72, P<0.01 with MIB-1). Elevated cox-2 expression was associated with high p53 expression (p<0.001) but not with clinicopathological features including age, sex, tumor size, histological grade, lymph node metastasis, and TNM stage. The results indicated that cox-2 may be involved in an early stage of squamous carcinogenesis of the esophagus, and that cox-2 overexpression was related to cell proliferation in esophageal squamous dysplasia and squamous cell carcinoma.

Analysis of Variance↗

PubMed2003

The ATP-dependent Lon protease of Mus musculus is a DNA-binding protein that is functionally conserved between yeast and mammals.

The ATP-dependent Lon protease is a multi-functional enzyme that is conserved from archae to mammalian mitochondria, which not only degrades protein substrates but also binds DNA. As a starting point toward understanding Lon function in development, the mouse Lon cDNA was cloned and the encoded protein was characterized in cultured mammalian cells, in yeast and in vitro. Mouse Lon shows 87, 40 and 33% amino acid similarity with the human, yeast and bacterial homologs, respectively. Expression of a single mouse Lon transcript is detected in liver>heart>kidney>testis and is present during early embryonic development. Endogenous as well as transiently overexpressed mouse Lon co-localize with mitochondrial markers and have half-lives greater than 24 h as determined by pulse-chase studies. Enzymatically active mouse Lon that hydrolyses ATP and degrades protein and peptide substrates in an ATP-dependent manner also specifically binds to single-stranded but not to double-stranded DNA oligonucleotides. We propose that binding to TG-rich DNA sequences has been conserved between the mouse and human proteins. In addition, the evolutionary conservation of mitochondrial Lon function is demonstrated by the ability of mouse Lon to substitute for the yeast protein in vivo.

ATP-Dependent Proteases↗

PubMed2003

Multiple amino acid residues confer temperature sensitivity to human influenza virus vaccine strains (FluMist) derived from cold-adapted A/Ann Arbor/6/60.

FluMist influenza A vaccine strains contain the PB1, PB2, PA, NP, M, and NS gene segments of ca A/AA/6/60, the master donor virus-A strain. These gene segments impart the characteristic cold-adapted (ca), attenuated (att), and temperature-sensitive (ts) phenotypes to the vaccine strains. A plasmid-based reverse genetics system was used to create a series of recombinant hybrids between the isogenic non-ts wt A/Ann Arbor/6/60 and MDV-A strains to characterize the genetic basis of the ts phenotype, a critical, genetically stable, biological trait that contributes to the attenuation and safety of FluMist vaccines. PB1, PB2, and NP derived from MDV-A each expressed determinants of temperature sensitivity and the combination of all three gene segments was synergistic, resulting in expression of the characteristic MDV-A ts phenotype. Site-directed mutagenesis analysis mapped the MDV-A ts phenotype to the following four major loci: PB1(1195) (K391E), PB1(1766) (E581G), PB2(821) (N265S), and NP(146) (D34G). In addition, PB1(2005) (A661T) also contributed to the ts phenotype. The identification of multiple genetic loci that control the MDV-A ts phenotype provides a molecular basis for the observed genetic stability of FluMist vaccines.

Animals↗

PubMed2003

Valvular and thoracic aortic calcium as a marker of the extent and severity of angiographic coronary artery disease.

BACKGROUND: The presence of calcified extracoronary structures as a useful indicator of underlying coronary artery disease (CAD) has not yet been established. The purpose of this study was to evaluate whether valvular and thoracic aortic calcification is associated with obstructive CAD. METHODS: We evaluated 99 patients who underwent both coronary angiography and electron beam tomography (EBT) coronary scanning. We identified the presence, absence, and amount of calcification in the aortic valve (AVC), mitral annulus (MAC), descending aorta (DAC), and ascending aorta (AAC). The extent of CAD was graded according to the number of vessels diseased (VD). RESULTS: Patients with multivessel disease (MVD) had a higher proportion of DAC. The presence of DAC significantly increased the specificity of EBT to detect CAD (58% with a calcium score >0 to 88% for calcium score>0 and DAC >0, P <.001). Both AAC and DAC were associated with a significantly higher rate of MVD in women (DAC, 63% in MVD vs 19% without, P <.01.; AAC, 65% vs 22%, P <.05). MAC had no relationship to either stenosis severity or the presence of obstructive CAD. AVC was the strongest predictor of the severity of CAD and predicted the presence of 3-vessel disease. CONCLUSION: AVC and thoracic aortic calcification as detected with EBT are associated with the angiographic extent and severity of CAD and add incremental diagnostic value to the coronary artery calcium score. MAC does not add incremental value.

Adult↗

PubMed2003

Measurement of the RT interval on ECG records during electron-beam CT.

RATIONALE AND OBJECTIVES: The R wave of the electrocardiogram is used widely as a trigger for cardiac imaging. This study was designed to determine the optimal interval between the R wave and end systole for triggering of electron-beam computed tomography (CT) in a group of patients with various heart rates who are undergoing assessment for coronary artery calcification. MATERIALS AND METHODS: A total of 862 consecutive asymptomatic patients referred for screening with electron-beam CT for coronary artery calcification were enrolled in the study. Patients' R-R, RT, and PR intervals were measured by using the software of the CT console computer. Correlation coefficients were computed and linear regression analyses were performed for all intervals measured. Results were analyzed according to patient age (three subgroups), sex (two subgroups), and heart rate (nine subgroups). Separate formulas for calculating the length of RT intervals in men and in women were developed. RESULTS: After correction for heart rate, a significant difference was found in mean RT and PR intervals between women and men, with the mean intervals in women being longer (P < .001). No significant difference was found in these intervals within the three age-defined subgroups (< or = 40, 41-60, and >60 years; P > .05). However, significant negative correlations were found between heart rates and the lengths of all measured intervals. The results of statistical analysis indicate that most of the variation in the R-R interval with different heart rates occurred in diastole and that the duration of systole was relatively constant. CONCLUSION: For optimal cardiac imaging, triggering should take place in late systole, avoiding the RT interval variability that occurs in diastole.

Adult↗

PubMed2003

[Study on the expression of DNA excision repair biomarkers in cispatin-treated lung cancer cell line].

OBJECTIVE: To study the expression levels of ERCC2, UDG, and PCNA in cisplatin-treated A549 cell line. METHOD: Comet assay, RT-PCR, and western blot were used to study the mRNA and protein expression levels of ERCC2, UDG, and PCNA. RESULTS: When treated with IC(20) cisplatin, the DNA damage level increased as the cisplatin treated time increased within 24 h of cisplatin treatment. The tail state 12 h and 24 h after treatment was 5.02 +/- 0.68 and 7.22 +/- 0.53 respectively, which was significantly higher than those of the controls (2.73 +/- 0.29). The tail state 24 h after treatment was not significantly different from that of the controls. The DNA damage level decreased to normal after cisplatin treatment in 24 h (tail state 3.64 +/- 0.7). The expression levels of ERCC2, UDG, PCNA protein (4.37 +/- 0.57, 5.47 +/- 0.46, 2.21 +/- 0.47 respectively) and mRNA (0.71 +/- 0.08, 0.74 +/- 0.06, 0.82 +/- 0.09) were increased significantly within 24 h exposure and decreased to normal 24 h after cisplatin treatment. The 3 enzymes' mRNA and protein expression increased when treated with cisplatin, but the changes of protein level were slower than those of mRNA levels. CONCLUSIONS: The DNA repair capability in A549 cells increases after cisplatin treatment. Cisplatin was a positive regulation of ERCC2, UDG, PCNA expression levels, which causes the increase of mRNA, and protein. The positive regulation only works in a short time and returns normal after 24 h of cisplatin treatment.

Antineoplastic Agents↗

PubMed2003

[Survival rate in mucoepidermoid carcinoma of salivary glands].

OBJECTIVE: To study the clinico pathologic factors influencing postoperative survival rate in mucoepidermoid carcinoma of salivary glands. METHODS: A retrospective study of seventy patients with mucoepidermoid carcinoma of salivary glands has been carried out. All cases underwent primary surgical resection in our hospital were followed up and clinicopathologic factors influencing the postoperative survival rate of patients were investigated. Statistical analysis was conducted using a computer program (SPSS). The data were statistically treated according to the Kaplan-Meier method. The Log rank tests were employed to assess the statistical significance of various groups. RESULTS: The 3-, 5- and 10-year overall survival rate were 90.66%, 88.85% and 86.63%, respectively. The patients with tumors' diameter less than 4 cm, early clinical stage (stage I and II), well differentiated tumor cells, without lymph nodes involvement, without local recurrence and metastasis after primary surgical resection had a long survival term. The patients with tumors' diameter more than 4 cm, with lymph nodes involvement, advanced clinical stage (stage III and IV), poor differentiated, with local recurrence and metastasis after primary surgical resection demonstrated a short survival term. CONCLUSION: TNM and clinical stage, the degree of differentiation, with or without local recurrence and metastasis after primary surgical resection are the important factors influencing the postoperative survival time.

Adolescent↗

PubMed2002

Apolipoprotein E4 forms a molten globule. A potential basis for its association with disease.

The amino-terminal domain of apolipoprotein (apo) E4 is less susceptible to chemical and thermal denaturation than the apoE3 and apoE2 domains. We compared the urea denaturation curves of the 22-kDa amino-terminal domains of the apoE isoforms at pH 7.4 and 4.0. At pH 7.4, apoE3 and apoE4 reflected an apparent two-state denaturation. The midpoints of denaturation were 5.2 and 4.3 m urea, respectively. At pH 4.0, a pH value known to stabilize folding intermediates, apoE4 and apoE3 displayed the same order of denaturation but with distinct plateaus, suggesting the presence of a stable folding intermediate. In contrast, apoE2 proved the most stable and lacked the distinct plateau observed with the other two isoforms and could be fitted to a two-state unfolding model. Analysis of the curves with a three-state unfolding model (native, intermediate, and unfolded) showed that the apoE4 folding intermediate reached its maximal concentration ( approximately 90% of the mixture) at 3.75 m, whereas the apoE3 intermediate was maximal at 4.75 m ( approximately 80%). These results are consistent with apoE4 being more susceptible to unfolding than apoE3 and apoE2 and more prone to form a stable folding intermediate. The structure of the apoE4 folding intermediate at pH 4.0 in 3.75 m urea was characterized using pepsin proteolysis, Fourier transform infrared spectroscopy, and dynamic light scattering. From these studies, we conclude that the apoE4 folding intermediate is a single molecule with the characteristics of a molten globule. We propose a model of the apoE4 molten globule in which the four-helix bundle of the amino-terminal domain is partially opened, generating a slightly elongated structure and exposing the hydrophobic core. Since molten globules have been implicated in both normal and abnormal physiological function, the differential abilities of the apoE isoforms to form a molten globule may contribute to the isoform-specific effects of apoE in disease.

Apolipoprotein E3↗

PubMed2002

Causes of interscan variability of coronary artery calcium measurements at electron-beam CT.

RATIONALE AND OBJECTIVES: The authors performed this study to investigate the causes of interscan variability of coronary artery calcium measurements at electron-beam computed tomography (CT). MATERIALS AND METHODS: Two sets of electron-beam CT scans were obtained in 298 consecutive patients who underwent electron-beam CT to screen for coronary artery calcium. Interscan variations of coronary artery calcium characteristics and the effects of heart rate, electrocardiographic (ECG) triggering method, image noise, and coronary motion on interscan variability were analyzed. RESULTS: The interscan mean variabilities were 21.6% (median, 11.7%) and 17.8% (median, 10.8%) with the Agatston and volumetric score, respectively (P < .01). Variability decreased with increasing calcification score (34.6% for a score of 11-50 and 9.4% for a score of 400-1,000, P < .0001). The absolute difference in Agatston score between scans was 44.1 +/- 95.6. The correlation coefficient between the first and second sets of scans was 0.99 (P < .0001). Lower interscan variability was found in younger patients (<60 years), patients with stable heart rates (heart rate changing less than 10 beats per minute during scanning), patients with no visible coronary motion, and those with an optimal ECG triggering method (P < .05 for all). Results of multivariate logistic analysis showed that changes in calcium volume, mean attenuation, and peak attenuation were significant predictors of interscan variability and caused the interscan variations of the coronary artery calcium measurements (r2 = 0.83, P < .0001). CONCLUSION: Coronary calcification at electron-beam CT varies from scan to scan. Volumetric scoring and optimal ECG triggering should be used to reduce interscan variability. Baseline calcium score and interscan variability must be considered in the evaluation of calcium progression.

Adult↗

PubMed2002

Reproducibility of three different scoring systems for measurement of coronary calcium.

BACKGROUND: There is great interest in measuring and tracking atherosclerosis using electron beam tomography (EBT). We sought to assess the reproducibility of two new software systems, InSight and AccuImage, and the console workstation of an EBT scanner for measuring coronary calcification. METHODS: Two sets of non-contrast EBT scans were obtained in 85 subjects. The calcium volume (CV) score and the Agatston score (AS) were analyzed and the relative differences were compared on three workstations. RESULTS: The intra- and inter-observer variabilities by InSight and AccuImage were both significantly better than variabilities on the console workstation. Both intra- and inter-observer differences for the AS were significantly smaller than those for the CV on each workstation. However, inter-scan variability was lower for the volume method (13.3%) as compared to the AS (17%). Scores were divided into tertiles (T), and the relative inter-scan differences for the AS in T-I (scores < 66) were higher than those in others (T-I 21.0%, T-II 11.9%, T-III 6.8%, p < 0.01). However, there were no significant differences for the CV method (T-I 19.9%, T-II 9.4%, and T-III 5.3%). Thus, while intra- and inter-observer differences with the AS method was lower than volume scoring, the CV inter-scan variability was significantly better. CONCLUSIONS: Both workstations using volumetric and Agatston methods have higher reliability than the console workstation. Inter- and intra-observer reproducibility was excellent (> 98%). There is minimal inter-scan variability for subjects with higher scores (> 65) for both scoring methods.

Aged↗

PubMed2002

The major phosphorylation sites of the respiratory syncytial virus phosphoprotein are dispensable for virus replication in vitro.

The phosphoprotein (P protein) of respiratory syncytial virus (RSV) is a key component of the viral RNA-dependent RNA polymerase complex. The protein is constitutively phosphorylated at the two clusters of serine residues (116, 117, and 119 [116/117/119] and 232 and 237 [232/237]). To examine the role of phosphorylation of the RSV P protein in virus replication, these five serine residues were altered to eliminate their phosphorylation potential, and the mutant proteins were analyzed for their functions with a minigenome assay. The reporter gene expression was reduced by 20% when all five phosphorylation sites were eliminated. Mutants with knockout mutations at two phosphorylation sites (S232A/S237A [PP2]) and at five phosphorylation sites (S116L/S117R/S119L/S232A/S237A [PP5]) were introduced into the infectious RSV A2 strain. Immunoprecipitation of (33)P(i)-labeled infected cells showed that P protein phosphorylation was reduced by 80% for rA2-PP2 and 95% for rA2-PP5. The interaction between the nucleocapsid (N) protein and P protein was reduced in rA2-PP2- and rA2-PP5-infected cells by 30 and 60%, respectively. Although the two recombinant viruses replicated well in Vero cells, rA2-PP2 and, to a greater extent, rA2-PP5, replicated poorly in HEp-2 cells. Virus budding from the infected HEp-2 cells was affected by dephosphorylation of P protein, because the majority of rA2-PP5 remained cell associated. In addition, rA2-PP5 was also more attenuated than rA2-PP2 in replication in the respiratory tracts of mice and cotton rats. Thus, our data suggest that although the major phosphorylation sites of RSV P protein are dispensable for virus replication in vitro, phosphorylation of P protein is required for efficient virus replication in vitro and in vivo.

Amino Acid Sequence↗

PubMed2002

Identification of temperature-sensitive mutations in the phosphoprotein of respiratory syncytial virus that are likely involved in its interaction with the nucleoprotein.

The phosphoprotein (P) of human respiratory syncytial virus (RSV) is an essential component of the viral RNA polymerase, along with the large polymerase (L), nucleocapsid (N), and M2-1 proteins. By screening a randomly mutagenized P gene cDNA library, two independent mutations, one with a substitution of glycine at position 172 by serine (G172S) and the other with a substitution of glutamic acid at position 176 by glycine (E176G), were identified to result in the loss of N-P interaction at 37 degrees C in the yeast two-hybrid assay. Both P mutants exhibited greatly reduced activity in supporting the replication and transcription of an RSV minigenome replicon at 37 and 39 degrees C. The G172S and E176G mutations were introduced individually into the RSV A2 (rA2) antigenomic cDNA, and recombinant viruses, rA2-P172 and rA2-P176, were obtained. Both viruses replicate as well as wild-type A2 virus in both Vero and HEp-2 cells at 33 degrees C, but each mutant virus exhibited temperature-sensitive replication in both cell lines. rA2-P176 is more temperature sensitive than rA2-P172. Coimmunoprecipitation of the N protein with each P mutant from virus-infected cells demonstrates that N-P interaction is impaired at 37 degrees C. In addition, the levels of replication of rA2-P172 and rA2-P176 in the lungs of mice and cotton rats were reduced. As is the case with the in vitro assays, rA2-P176 is more restricted in replication in the lower respiratory tract of mice and cotton rats than rA2-P172. During in vitro passage at 37 degrees C, the E176G mutation in rA2-P176 was rapidly changed from glycine to predominantly aspartic acid; mutations to cysteine or serine were also detected. All of the revertants lost the temperature-sensitive phenotype. To analyze the importance of the amino acids in the region from positions 161 to 180 for the P protein function, additional mutations were introduced and their functions were analyzed in vitro. A double mutant containing both G172S and E176G changes in the P gene, substitution of the three charged residues at positions 174 to 176 by alanine, and a deletion of residues from positions 161 to 180 completely abolished the P protein function in the minigenome assay. Thus, the amino acids at positions 172 and 176 and the adjacent charged residues play critical roles in the function of the P protein.

Animals↗

PubMed2002

EKG-triggered CT data acquisition to reduce variability in coronary arterial calcium score.

PURPOSE: To test the hypothesis that computed tomographic (CT) scanning during optimal electrocardiographic (EKG) triggering can minimize image motion artifact and reduce interexamination variation of coronary arterial calcification (CAC) score at electron-beam CT. MATERIALS AND METHODS: Two hundred patients underwent electron-beam CT once and again 5 minutes later to evaluate interexamination variability of CAC score. Group 1 (104 patients) underwent scanning with use of an optimal EKG-triggering protocol (EKG triggering performed individually at the time of least coronary arterial motion during the cardiac cycle); group 2 (96 patients) underwent scanning with use of conventional 80% R-R interval triggering (the most common protocol with the electron-beam CT scanner). Interexamination, intraobserver, and interobserver variations of CAC measurements were compared between groups by using unpaired t tests for both Agatston and volumetric scores (in square millimeters). RESULTS: Coronary arterial motion artifacts were found in 26% (27 of 104) versus 80% (77 of 96) of patients in groups 1 and 2, respectively (P <.0001). Intraobserver, interobserver, and interexamination variabilities in volumetric score were derived, with values of 1.2%, 9.2%, and 15.9% in group 1 and 2.1%, 11.3%, and 25.9% in group 2, respectively. Interexamination variabilities in both Agatston and volumetric score were significantly reduced with individualized EKG triggering, as compared with conventional triggering (P <.05), but intra- and interobserver variabilities were not (P >.05). CONCLUSION: Optimal EKG triggering improves the reproducibility of CAC measurement by reducing coronary arterial motion artifacts.

Arteries↗

PubMed2002

Regulation of Fas (CD95)-induced apoptosis by nuclear factor-kappaB and tumor necrosis factor-alpha in macrophages.

The APO-1/Fas ligand (FasL) and tumor necrosis factor-alpha (TNF-alpha) are two functionally related molecules that induce apoptosis of susceptible cells. Although the two molecules have been reported to induce apoptosis via distinct signaling pathways, we have shown that FasL can also upregulate the expression of TNF-alpha, raising the possibility that TNF-alpha may be involved in FasL-induced apoptosis. Because TNF-alpha gene expression is under the control of nuclear factor-kappaB (NF-kappaB), we investigated whether FasL can induce NF-kappaB activation and whether such activation plays a role in FasL-mediated cell death in macrophages. Gene transfection studies using NF-kappaB-dependent reporter plasmid showed that FasL did activate NF-kappaB promoter activity. Gel shift studies also revealed that FasL mobilized the p50/p65 heterodimeric form of NF-kappaB. Inhibition of NF-kappaB by a specific NF-kappaB inhibitor, caffeic acid phenylethyl ester, or by dominant expression of the NF-kappaB inhibitory subunit IkappaB caused an increase in FasL-induced apoptosis and a reduction in TNF-alpha expression. However, neutralization of TNF-alpha by specific anti-TNF-alpha antibody had no effect on FasL-induced apoptosis. These results indicate that FasL-mediated cell death in macrophages is regulated through NF-kappaB and is independent of TNF-alpha activation, suggesting the antiapoptotic role of NF-kappaB and a separate death signaling pathway mediated by FasL.

Animals↗

PubMed2002

Noninvasive assessment of coronary artery bypass graft patency and flow characteristics by electron-beam tomography.

OBJECTIVE: To evaluate the flow characteristics and accuracy for the detection of patent or occluded coronary artery bypass grafts (CABG) with multi-slice flow study of electron-beam tomography (EBT). METHODS: One hundred and twenty-three patients who had undergone CABG surgery were enrolled in this study. Flow datasets were assessed with time-density curves by EBT. The EBT results were blindly compared with post-operative cardiac catheterizations in 26 patients. RESULTS: Image quality was adequate to evaluate in 111 patients (90.2%). Flow curves of bypass grafts were technically adequate in 265 of 309 (85.8%) saphenous-vein grafts (SVG) and 35 of 56 (62.5%) internal mammary artery (IMA) grafts (p < 0.05). In comparison to conventional angiographic results, EBT correctly identified 14 of 16 occluded grafts (sensitivity, 87.5%) and 68 of 75 patent grafts (specificity, 90.7%), yielding an accuracy of 90.1%. The intra-graft flows of the IMA and SVG were 4.9 +/- 2.2 ml/min/g and 6.9 +/- 2.8 ml/min/g, respectively (p < 0.001), which was 31.6 +/- 20.4% and 39.4 +/- 21.9% of the ascending aorta's flow (16.7 +/- 5.0 ml/min/g) (p < 0.001). CONCLUSION: EBT flow study can be used in the assessment of CABG patency and quantification of intra-graft flow of patent CABG vessels.

Adult↗