Showing papers by "Ming Chuan University published in 2006"

Optimal design for step-stress accelerated degradation tests

Abstract: Today, many products are designed to function for a long period of time before they fail. For such highly-reliable products, collecting accelerated degradation test (ADT) data can provide useful reliability information. However, it usually requires a moderate sample size to implement an ADT. Hence, ADT is not applicable for assessing the lifetime distribution of a newly developed or very expensive product which only has a few available test units on hand. Recently, a step-stress ADT (SSADT) has been suggested in the literature to overcome the above difficulty. However, in designing an efficient SSADT experiment, the issue about how to choose the optimal settings of variables was not discussed, such as sample size, measurement frequency, and termination time. In this study, we first use a stochastic diffusion process to model a typical SSADT problem. Next, under the constraint that the total experimental cost does not exceed a predetermined budget, the optimal settings of these variables are obtained by minimizing the asymptotic variance of the estimated 100p/sup th/ percentile of the product's lifetime distribution. Finally, an example is used to illustrate the proposed method.

Under-Sampling Approaches for Improving Prediction of the Minority Class in an Imbalanced Dataset

Abstract: The most important factor of classification for improving classification accuracy is the training data. However, the data in real-world applications often are imbalanced class distribution, that is, most of the data are in majority class and little data are in minority class. In this case, if all the data are used to be the training data, the classifier tends to predict that most of the incoming data belong to the majority class. Hence, it is important to select the suitable training data for classification in the imbalanced class distribution problem. In this paper, we propose cluster-based under-sampling approaches for selecting the representative data as training data to improve the classification accuracy for minority class in the imbalanced class distribution problem. The experimental results show that our cluster-based under-sampling approaches outperform the other under-sampling techniques in the previous studies.

Improvements of Complex-Valued Hopfield Associative Memory by Using Generalized Projection Rules

Abstract: In this letter, new design methods for the complex-valued multistate Hopfield associative memories (CVHAMs) are presented. We show that the well-known projection rule proposed by Personnaz can be generalized to complex domain such that the weight matrix of the CVHAM can be designed by using a simple and effective method. The stability of the proposed CVHAM is analyzed by using energy function approach which shows that in synchronous update mode the proposed model is guaranteed to converge to a fixed point from any given initial state. Moreover, the projection geometry of the generalized projection rule (GPR) is discussed. In order to enhance the recall capability, a strategy of eliminating the spurious memories is also reported. The validity and the performance of the proposed methods are investigated by computer simulation

Can high performance work systems really lead to better performance

Abstract: Purpose – This study presents a conceptual scheme concerning the core constituents of high‐performance work system (HPWS) and examines their effects on firm performance.Design/methodology/approach – This study proposes a conceptual scheme incorporating the universalistic and the configurational perspectives of strategic human resource management. The effect of HPWS on firm performance is empirically tested using data collected from publicly listed companies in Taiwan, as well as multinational companies' branch offices in Taiwan.Findings – Initial factor analysis on HPWS practices supports this conceptual scheme. Using the structural equation modeling technique (AMOS 4.0) better‐performing firms were found to invest in more sophisticated HRM practices, which further enhanced organizational performance.Research limitations/implications – Surveys conducted in other countries can expand the external validity of this study's findings.Originality/value – While most previous research on HPWS involves regression‐...

Molecular characterization of adenocarcinoma and squamous carcinoma of the uterine cervix using microarray analysis of gene expression.

Abstract: In an attempt to understand the molecular mechanisms for the different clinical features between adenocarcinoma/adenosquamous carcinoma (AC/ASC) and squamous carcinoma (SC) of the uterine cervix, we analyzed gene expression profiles of different histological subtypes of cervical cancer. Cancer specimens and the surrounding normal tissue counterparts were separately collected from cervical cancer patients undergoing type III radical hysterectomy. Paired total RNA (cancer and normal tissues) was isolated and analyzed with cDNA microarrays containing duplicate spots of 7 334 sequence-verified human cDNA clones. Selected differentially expressed genes specific for AC or SC were further verified using real-time quantitative polymerase chain reaction (RTQ-PCR) and immunohistochemistry. Genes, including CEACAM5, TACSTD1, S100P and MSLN were upregulated in AC. Contrarily, genes involved in epidermal differentiation complex such as S100A9 and ANXA8 were upregulated in SC. Cross-validation of the results using an independent but comparable group of patients with known long-term outcomes (n = 63, median follow-up 70.3 months; range, 4-208 months) showed that the correlation between the selected 6 differentially expressed genes and histology was highly significant. CEACAM5 (p < 0.0001) and TACSTD1 (p = 0.009) were significant prognostic factors by multivariate Cox proportional hazards regression analysis. The combination of cDNA microarray, RTQ-PCR and immunohistochemical results of this study showed that it is possible to define different gene profiles for AC and SC. Moreover, TACSTD1 expression may be a novel poor prognostic factor.

Codon Optimization of Candida rugosa lip1 Gene for Improving Expression in Pichia pastoris and Biochemical Characterization of the Purified Recombinant LIP1 Lipase

Abstract: An important industrial enzyme, Candida rugosa lipase (CRL) possesses several different isoforms encoded by the lip gene family (lip1-lip7), in which the recombinant LIP1 is the major form of the CRL multigene family. Previously, 19 of the nonuniversal serine codons (CTG) of the lip1 gene hav been successfully converted into universal serine codons (TCT) by overlap extension PCR-based multiple-site-directed mutagenesis to express an active recombinant LIP1 in the yeast Pichia pastoris. To improve the expression efficiency of recombinant LIP1 in P. pastoris, a regional synthetic gene fragment of lip1 near the 5' end of a transcript has been constructed to match P. pastoris-preferred codon usage for simple scale-up fermentation. The present results show that the production level (152 mg/L) of coLIP1 (codon-optimized LIP1) has an overall improvement of 4.6-fold relative to that (33 mg/L) of non-codon-optimized LIP1 with only half the cultivation time of P. pastoris. This finding demonstrates that the regional codon optimization the lip1 gene fragment at the 5' end can greatly increase the expression level of recombinant LIP1 in the P. pastoris system. More distinct biochemical properties of the purified recombinant LIP1 for further industrial applications are also determined and discussed in detail.

Paclitaxel (Taxol) upregulates expression of functional interleukin-6 in human ovarian cancer cells through multiple signaling pathways

Abstract: Paclitaxel (Taxol) is an antineoplastic agent that specifically targets microtubules and arrests cells at the G2/M phase of the cell cycle. In addition to mitotic arrest, the activation of c-Jun N-terminal kinase (JNK) signaling pathway has been demonstrated to be involved in the process leading to apoptosis. In an attempt to explore what genes are transcriptionally regulated by the activated JNK signaling pathway upon paclitaxel treatment, we used cDNA microarrays to analyse the changes of gene expression in human ovarian cancer cells that were treated with paclitaxel and/or the JNK inhibitor SP600125. Among 20 genes that were specifically regulated by the paclitaxel-activated JNK pathway, interleukin (IL)-6 was shown to elicit function through the JAK-STAT signaling pathway in an autocrine and/or paracrine fashion. Subsequently, we identified that 87.5% of eight tested ovarian cancer lines secreted detectable levels of IL-6, which could be further upregulated 2-3.2 fold by 1 microM paclitaxel. Dissection on regulatory pathways for IL-6 indicated that (i) when ovarian cancer cells were treated with paclitaxel at low but clinically achievable concentrations (exemplified by 1 microM in this study), the JNK signaling pathway was the major stimulator of IL-6 gene regulation and (ii) at suprapharmacologically high concentrations (exemplified by 50 microM), paclitaxel exerted lipopolysaccharide-like effects, most likely through the Toll-like receptor 4 signaling pathway. Collectively, these results suggest that paclitaxel upregulates functional IL-6 expression in human ovarian cancer cells through multiple signaling pathways.

Gene cloning, expression, and biochemical characterization of a recombinant trehalose synthase from Picrophilus torridus in Escherichia coli.

Abstract: A trehalose synthase (TSase) gene from a hyperacidophilic, thermophilic archaea, Picrophilus torridus, was synthesized using overlap extension PCR and transformed into Escherichia coli for expression. The purified recombinant P. torridus TSase (PTTS) showed an optimum pH and temperature of 6.0 and 45 °C, respectively, and the enzyme maintained high activity at pH 5.0 and 60 °C. Kinetic analysis showed that the enzyme has a 2.5-fold higher catalytic efficiency (kcat/KM) for maltose than for trehalose, indicating maltose as the preferred substrate. The maximum conversion rate of maltose into trehalose by the enzyme was independent of the substrate concentration, tended to increase at lower temperatures, and reached ≈71% at 20 °C. Enzyme activity was inhibited by Hg2+, Al3+, and SDS. Five amino acid residues that are important for α-amylase family enzyme catalysis were shown to be conserved in PTTS (Asp203, Glu245, Asp311, His106, and His310) and required for its activity, suggesting this enzyme might employ...

High-payload image steganography using two-way block matching

Abstract: This letter presents a novel image steganography method that utilizes a two-way block-matching procedure to search for the highest similarity block for each block of the important image. The bases and indexes obtained together with some not-well-matched blocks are recorded in the least significant bits of the cover image using a hop scheme. The method exhibits a high data payload, which reduces the storage and transmission-time requirements and also provides a method that prevents an observer from selectively blocking the transmission of the important image.

A Gene Expression Profile for Vascular Invasion can Predict the Recurrence After Resection of Hepatocellular Carcinoma: a Microarray Approach

Abstract: Recurrence after hepatocellular carcinoma (HCC) resection is the major obstacle to improved survival. The presence of vascular invasion (VI) in pathology specimens is a well-known unfavorable prognostic factor for HCC recurrence. Though some VI-related genes have been reported, their association with recurrence-free survival is not known. We hypothesized that a gene expression profile for VI can predict the recurrence of HCC after liver resection. Eighteen patients receiving complete HCC resection were included as a “training group”. Genome-wide gene expression profile was obtained for each tumor using a microarray technique. Datasets were subjected to clustering analysis supervised by the presence or absence of VI to obtain 14 discriminative genes. We then applied those genes to execute pattern recognition using the k-Nearest Neighbor (KNN) classification method, and the best model for this VI gene signature to predict recurrence-free survival in the training group was obtained. The resulting model was then tested in an independent “test group” of 35 patients. A 14-gene profile was extracted which could accurately separate ten patients with VI and eight patients without VI in the “training group”. In the “test group”, significant difference in disease-free survival was found between patients predicted to have and not to have recurrence (P = .02823). In patients with stage_I disease, this model can also predict outcomes (P = .000205). Using the 14-gene expression profile extracted from microarrays based on the presence of VI can effectively predict recurrence after HCC resection. This approach might facilitate “personalized medicine” for HCC patients after surgical resection.

Association of insulin resistance and hematologic parameters: study of a middle-aged and elderly Chinese population in Taiwan.

Abstract: Background Chronic inflammation is a common feature related to changes in hematologic parameters in insulin resistance. The aims of this study were to explore the relationship between hematologic parameters and insulin resistance, and to establish a gerontologic profile for following studies. Methods Residents aged over 40 years in 3 major townships in I-Lan County participating in the Adult Health Examination were invited for the study. Diagnosis of diabetes mellitus (DM) was done according to American Diabetes Association criteria. Insulin resistance was measured by homeostasis model assessment (HOMA-IR), and subjects with the highest tertile of HOMA-IR were defined as being insulin resistant. Hematologic parameters including white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin, and platelet count were measured for comparisons. Results A total of 857 subjects (mean age, 64.6 ± 11.2 years; male/female, 373/484) participated in this study. Their mean body mass index (BMI) was 24.5 ± 3.7 kg/m 2 , and 42.4% of them were obese and 21.8% were overweight. The overall prevalence of DM was 15.4% (7.7% were previously diagnosed and 7.7% were newly diagnosed), and impaired fasting glucose was 7.2%. Trend analyses confirmed that age, BMI, HOMA-IR, WBC and platelet counts were significantly increased as glycemic metabolism exacerbated ( p = 0.007, vs. 49.7%, p 2 vs. 23.7 ± 3.3 kg/m 2 , p vs. 0.7 ± 0.3, p 0.001), WBC count (6686.9 ± 1889.2/mm 3 vs. 5942.9 ± 1740.4/mm 3 , p 3 /mm 3 vs. 231.0 ± 62.2 × 10 3 /mm 3 , p = 0.011), but not age (64.5 ± 11.0 years vs. 64.6 ± 11.4 years, p = 0.93) or RBC count (4.6 ± 0.6 M/mm 3 vs. 4.6 ± 0.6 M/mm 3 , p = 0.76). When age and sex were controlled, HOMA-IR significantly correlated with WBC count ( γ = 0.23, p γ = 0.09, p = 0.007). However, by multiple logistic regression, female gender, overweight and obesity, and elevated WBC count were all found to be independent risk factors of insulin resistance, but age, RBC and platelet counts were not. Conclusion Elevated WBC count but not RBC count was significantly associated with insulin resistance and glycemic metabolism. The relationship between platelet count and insulin resistance deserves further investigations.

A proteomics study of the mung bean epicotyl regulated by brassinosteroids under conditions of chilling stress

Abstract: Mung bean CYP90A2 is a putative brassinosteroid (BR) synthetic gene that shares 77% identity with the Arabidopsis CPD gene. It was strongly suppressed by chilling stress. This implies that exogenous treatment with BR could allow the plant to recover from the inhibited growth caused by chilling. In this study, we used proteomics to investigate whether the mung bean epicotyl can be regulated by brassinosteroids under conditions of chilling stress. Mung bean epicotyls whose growth was initially suppressed by chilling partly recovered their ability to elongate after treatment with 24-epibrassinolde; 17 proteins down-regulated by this chilling were re-up-regulated. These up-regulated proteins are involved in methionine assimilation, ATP synthesis, cell wall construction and the stress response. This is consistent with the re-up-regulation of methionine synthase and S-adenosyl-L-methionine synthetase, since chilling-inhibited mung bean epicotyl elongation could be partially recovered by exogenous treatment with DL-methionine. This is the first proteome established for the mung bean species. The regulatory relationship between brassinosteroids and chilling conditions was investigated, and possible mechanisms are discussed herein.

Extracting named entities using support vector machines

Abstract: Identifying proper names, like gene names, DNAs, or proteins is useful to help researchers to mining the text information. Learning to extract proper names in natural language text is a named entity recognition (NER) task. Previous studies focus on combining abundant human made rules, trigger words, to enhance the system performance. However these methods require domain experts to build up these rules and word set which relies on lots of human efforts. In this paper, we present a robust named entity recognition system based on support vector machines (SVM). By integrating with rich feature set and the proposed mask method, the system performance is satisfactory on the MUC-7 and biology named entity recognition tasks which outperforms famous machine learning-based method, such as hidden markov model (HMM), and maximum entropy model (MEM). We compare our method to previous systems that were performed on the same data set. The experiments show that when training with the MUC-7 data set, our system achieves 86.4 in F(β=1) rate and 81.57 for the biology corpus. Besides, our named entity system is able to handle real time processing applications, the turn around time on a 63 K words document set is less than 30 seconds.

Concomitant pelvic organ prolapse surgery with TVT procedure

Abstract: The aim of this study is to evaluate the efficacy and feasibility of concomitant pelvic reconstructive surgery with tension-free vaginal tape (TVT) procedure to treat pelvic organ prolapse women with urodynamic stress incontinence (USI) or occult USI. Seventy-five women with pelvic organ prolapse and diagnosed as USI or occult USI were enrolled in this study. All patients with USI or occult USI underwent TVT treatment under general anesthesia, combined with transvaginal total hysterectomy (VTH), anterior-posterior colporrhaphy (APC), and/or right sacrospinous ligament suspension (SSS) reconstructive surgeries. The subjective assessment was evaluated by using a visual analog scale (VAS) score and a urinary symptomatic questionnaire. The objective assessment was carried out with a 1-h pad test, cough stress test, and urodynamic examination. Of the 75 patients, 35 patients with grade III uterine prolapse underwent VTH and APC, 30 patients with grade IV uterine prolapse underwent VTH, SSS, and APC, and the other 10 patients who had previous hysterectomy with total vaginal vault prolapse underwent SSS and APC. The mean follow-up interval was 25 months (12-42 months). The mean hospitalization was 5.9 days and the mean catheterization time was 3.8 days. The subjective success rate for the treatment of urine incontinence was 88%, and the objective complete cure rate was 84%. The rate of postoperative complications with persistent urinary urgency, de novo detrusor overactivity, dysfunctional voiding, and tape erosion were 50, 8, 12, and 1.3%, respectively. There were no bladder perforations during the TVT procedure and no perioperative complications requiring conversion to laparotomy. Pelvic organ prolapse women with USI or occult USI can be treated by reconstructive surgeries combined with a TVT procedure to treat and prevent postoperative USI.

Efficient production of active recombinant Candida rugosa LIP3 lipase in Pichia pastoris and biochemical characterization of the purified enzyme

Abstract: Candida rugosa lipase (CRL), an important industrial enzyme, possesses several different isoforms encoded by the high-identity lip gene family (lip1 to lip7). In this study, an additional N-terminal peptide in front of the lip3 gene was removed by PCR, and the 18 nonuniversal serine codons (CTG) of the lip3 gene were converted into universal serine codons (TCT) by means of an overlap extension PCR-based multiple-site-directed mutagenesis to express an active recombinant LIP3 in the yeast Pichia pastoris. The regional synthetic DNA fragment (339 bp) is first recombined by primer assembly with 20 overlapping nucleotides, followed by specific overlap extension PCR with outside primers containing restriction enzyme sites for directional cloning into the pGAPZalphaC vector. The results show that the production yield (0.687 unit/mL) of N-fused lip3 (nflip3) has an overall improvement of 69-fold relative to that (0.01 unit/mL) of lip3 and of 52-fold (0.47 unit/mL) of codon-optimized lip3 (colip3) relative to that (0.01 unit/mL) of non-codon-optimized lip3 (lip3), with the cultivation time set at 5 days. This finding demonstrates that the reservation of the N terminus and the regional codon optimization of the lip3 gene fragment at the 5' end can greatly increase the expression level of recombinant LIP3 in the P. pastoris system. The purified recombinant LIP3 shows distinct biochemical properties compared with other isoforms.

Domain connected graph: the skeleton of a closed 3D shape for animation

Abstract: In previous research, three main approaches have been employed to solve the skeleton extraction problem: medial axis transform (MAT), generalized potential field and decomposition-based methods. These three approaches have been formulated using three different concepts, namely surface variation, inside energy distribution, and the connectivity of parts. By combining the above mentioned concepts, this paper creates a concise structure to represent the control skeleton of an arbitrary object.First, an algorithm is proposed to detect the end, connection and joint points of an arbitrary 3D object. These three points comprise the skeleton, and are the most important to consider when describing it. In order to maintain the stability of the point extraction algorithm, a prong-feature detection technique and a level iso-surfaces function-based on the repulsive force field was employed. A neighborhood relationship inherited from the surface able to describe the connection relationship of these positions was then defined. Based on this relationship, the skeleton was finally constructed and named domain connected graph (DCG). The DCG not only preserves the topology information of a 3D object, but is also less sensitive than MAT to the perturbation of shapes. Moreover, from the results of complicated 3D models, consisting of thousands of polygons, it is evident that the DCG conforms to human perception.

Interleukin-1 receptor antagonist (IL-1RA) prevents apoptosis in ex vivo expansion of human limbal epithelial cells cultivated on human amniotic membrane

Abstract: Stem cells of the corneal epithelium have been found to be located exclusively at the anatomical junction between the cornea and the conjunctiva, the limbus. Ex vivo expanded limbal epithelial cells on amniotic membrane (AM) are capable of restoring the corneal surface with limbal stem cell deficiency. Recent studies indicate that intact AM preserves the limbal epithelial phenotype and that distinct epithelial morphology is noted among various culture matrix. However, the factors in response to the interaction between limbal epithelial cells and AM were not well understood. Using Annexin V-fluorescein isothiocyanate staining, we found that human limbal epithelial cells expanded on intact human AM demonstrated fewer apoptotic cells as compared with those on plastic dishes. To identify the anti-apoptotic factors, we performed cDNA microarray analysis and showed that interleukin-1 receptor antagonist (IL-1RA) was overexpressed in cultures on intact AM, which was confirmed by reverse transcription-polymerase chain reaction (RT-PCR), real-time quantitative PCR (Q-PCR) and enzyme-linked immunosorbent assay. In addition, we also noted that the phenomenon of apoptosis detected in cultures on plastic dishes could be reversed by adding recombinant IL-1RA protein into the media, whereas apoptosis of limbal epithelial cells cultivated on intact AM could be induced by exogenous neutralizing IL-1RA neutralizing antibody. These results demonstrated that intact human AM may prevent cultured human limbal epithelial cells from undergoing apoptosis. IL-1RA might be a candidate mediator to exert as an anti-apoptotic molecule during the interaction between human limbal epithelial cells and intact human AM.

The Relational Behavior Between Wholesaler and Retailer Travel Agencies: Evidence From Taiwan

Abstract: This study examined the relational behavior model between wholesale and retail travel agencies. The conceptual model of the study is based on the relational behavior model and relationship marketing literature. The study surveyed 201 retailers in Taiwan. The results indicated that wholesalers' relational behaviors (initiating, signaling, and disclosing behaviors), offering support, and end-users' satisfaction positively influence the relationship quality between travel wholesalers and retailers. In turn, relationship quality positively influences retailers' loyalty and wholesalers' market share. The study highlights the moderators of relationship age and product importance and suggests that they have salient influences on the antecedents and consequences of the relational behavior models. Specifically, retailers' loyalty is reduced when relationship age is short and products become less important. This study supports the theoretical model of relational behavior between travel wholesalers and retailers and...

Understanding Agent-Based On-Line Persuasion and Bargaining Strategies: An Empirical Study

Abstract: The application of software agents to facilitate on-line trading was an important initiative at the dawn of e-commerce, but researchers have not studied the effects of agent-to-human persuasion under different customer characteristics. This paper investigates the application of several persuasion and bargaining strategies to customers with different elaboration levels. Two experiments based on the Elaboration Likelihood Model (ELM) were conducted in an on-line used-car-selling scenario. A software agent interacting with customers as a virtual salesperson adopted a persuasion strategy that was either relevant or irrelevant to product attributes and a bargaining strategy that was either tough or moderate. The results show that if the sales agent's strategies accord with the customer's characteristics, the customer's purchasing attitude can be changed and the seller's profit increased. This finding can be used as a guideline in designing sales agents for on-line sales activities.

Unemployment and suicide: Panel data analyses

Abstract: This study uses two panel data sets for both Taiwan and other Asian countries, and employs fixed-effects models to examine the relationship between the unemployment rate and the suicide death rate. The research results in both cases indicate that the suicide death rate moves counter-cyclically with the unemployment rate. At the same time, the death rate for males, those who are older, and those with higher levels of education are relatively high. However, the higher the income, the lower will be the suicide death rate.

A Surveillance Spyware Detection System Based on Data Mining Methods

Abstract: The problem of spyware is incredibly serious and exceeds anyone’s imagination. Combining static and dynamic analyses, we propose an integrated architecture to defend against surveillance spyware in this paper. Features extracted from both static and dynamic analyses are ranked according to their information gains. Then using top significant features we construct a Support Vector Machine (SVM) classifier for each client. In order to keep the classifier update-to-date, there is a machine playing as server to collect reports from all clients, retrain, and redistribute the new classifier to each client. Our surveillance spyware detection system (SSDS) has an overall accuracy rate up to 97.9% for known surveillance spywares and 96.4% for unknown ones.

Impact of a cultural belief about ghost month on delivery mode in Taiwan

Abstract: Background: Many Chinese believe the lunar month of July, “ghost month” is inauspicious for major surgical procedures. This study hypothesised that caesaren delivery (CS) rates will be significantly lower during lunar July, and higher than normal during June, representing pre-emptive caesaren delivery to avoid delivering in July. Methods: Population based data from Taiwan on all singleton deliveries during 1997–2003 (1 750 862 cases) were subjected to multivariate autoregressive integrated moving average (ARIMA) modelling, adjusting for major obstetric complications (previous CS, breech presentation, dystocia, and fetal distress). Results: ARIMA intervention models showed significantly lower CS rates in lunar July, and among younger age groups (p Conclusions: Adjusted CS rates during the ghost month are significantly lower than other months. Lunar June shows an increase in deliveries of previous CS mothers (almost all by CS), suggesting elective CS to pre-empt CS in July. A major policy implication is that health education must be launched to dissipate the cultural belief about the ghost month. Evidence also implies some proportion of clinically un-indicated CS in other months, showing the need for professional and policy initiatives to reduce unnecessary CS. Policy makers and researchers in other countries should be alert to cultural beliefs associated with delivery to enable informed delivery choices by mothers.

Reperfusion Liver Injury Induces Down-Regulation of eNOS and Up-Regulation of iNOS in Lung Tissues

Abstract: Objectives Acute lung injury and inflammation can occur after hepatic ischemia/reperfusion (I/R). Little is known regarding the possible role of nitric oxide synthase expression in this complex type of lung injury. Methods Real-time polymerase chain reactions and immunohistochemistry were used to assess the mRNA and protein expression of eNOS and iNOS in lung tissue after I/R challenge to the liver. Ischemia was induced by clamping the hepatic artery and portal vein for 40 minutes. After flow was restored, the liver was reperfused for 300 minutes. Blood samples were collected to assay three inflammatory parameters: tumor necrosis factor (TNF)-α, hydroxyl radicals, and NO. Lung lavage samples were assayed for protein and myeloperoxidase. The expression of eNOS and iNOS in lung tissues (n = 3) was also evaluated after I/R challenge to the liver. The iNOS inhibitor aminoguanidine was also tested in this I/R model. Results Reperfusion of the liver produced increased blood concentrations of TNF, hydroxyl radicals, and NO (P Conclusions I/R injury to the liver induced lung injury involving systemic inflammatory responses and iNOS expression. Administration of aminoguanidine significantly attenuated the injury, suggesting that iNOS expression may play a critical role in lung injury induced by I/R of the liver.