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Li Chen

Publications and source records attributed to Li Chen.

At least 145 records · Page 8Linked to original sources
PubMed2005

Decreased expression of fibulin-5 correlates with reduced elastin in thoracic aortic dissection.

BACKGROUND: Thoracic aortic aneurysmal diseases are characterized by degeneration of elastin within the aortic wall. Although proteinases, such as matrix metalloproteinase, appear to contribute to elastin degradation, little is known about the role of elastic fiber assembly in such diseases. Fibulin-5 is an extracellular protein that is expressed in the vascular basement membrane and regulates elastic fiber assembly by microfibril machinery. In this study, we examined whether thoracic aortic dissection (TAD) is associated with abnormal fibulin-5 expression. METHODS: Intraoperative aortic samples were obtained from 21 patients with proximal aortic dissection. Control aortic tissue was obtained from 11 organ donors, heart transplant recipients, and patients undergoing coronary artery bypass. An in vitro culture of vascular smooth muscle cells was obtained from 2 TAD patients and 1 control subject. To evaluate elastin expression, we stained tissue sections with Verhoeff-Van Gieson stain. Fibulin-5 messenger RNA (mRNA) expression was determined by quantitative real-time reverse-transcriptase-polymerase chain reaction. RESULTS: Aortic fibulin-5 mRNA and elastin content were decreased in TAD patients, compared with controls (P=.001 and P=.02, respectively). Decreased fibulin-5 expression strongly correlated with decreased amounts and fragmentation of elastin in aortic samples from patients with TAD (r=0.83, P < .0001 and F=20.7, P < .0001 respectively). The fibulin-5 mRNA in aortic vascular smooth muscle cells collected from TAD demonstrated a 38% decrease in expression, compared with the control. CONCLUSIONS: Patients with proximal aortic dissection exhibited significantly decreased expression of aortic fibulin-5. Decreased fibulin-5 may contribute to the pathogenesis of aortic dissection by impairing elastic fiber assembly.

Aged↗
PubMed2005

A soft double regularization approach to parametric blind image deconvolution.

This paper proposes a blind image deconvolution scheme based on soft integration of parametric blur structures. Conventional blind image deconvolution methods encounter a difficult dilemma of either imposing stringent and inflexible preconditions on the problem formulation or experiencing poor restoration results due to lack of information. This paper attempts to address this issue by assessing the relevance of parametric blur information, and incorporating the knowledge into the parametric double regularization (PDR) scheme. The PDR method assumes that the actual blur satisfies up to a certain degree of parametric structure, as there are many well-known parametric blurs in practical applications. Further, it can be tailored flexibly to include other blur types if some prior parametric knowledge of the blur is available. A manifold soft parametric modeling technique is proposed to generate the blur manifolds, and estimate the fuzzy blur structure. The PDR scheme involves the development of the meaningful cost function, the estimation of blur support and structure, and the optimization of the cost function. Experimental results show that it is effective in restoring degraded images under different environments.

Algorithms↗
PubMed2005

Study of antiepileptic effect of extracts from Acorus tatarinowii Schott.

PURPOSE: To study the antiepileptic properties of extracts from rhizomes of Acorus tatarinowii Schott (ATS). METHODS: The decoction and volatile oil were extracted from rhizomes of ATS by traditional decocting and supercritical CO(2) fluid extraction (SFE-CO(2)) methods. Maximal electroshock (MES), pentylenetetrazol (PTZ) maximal seizure, and prolonged PTZ kindling models were used to test their anticonvulsive properties. The gamma-aminobutyric acid (GABA) immunohistochemical reaction (IR) was used to study GABAergic neuron changes in the PTZ kindling model and the effects of treatment. RESULTS: Both decoction (dose; 10-20 g/kg) and volatile oil (1.25 g/kg) of ATS decreased the convulsive rate significantly in the MES model. Decoction of ATS was shown to be effective in the PTZ model with both decreased convulsive and mortality rates. The volatile oil of ATS failed to prevent seizures in the dose range tested, although prolonged seizure latency and decreased mortality were found at a dose of 1.25 g/kg. In the PTZ kindling model, GABA-IR neurons decreased obviously compared with the normal group. In the groups treated with the decoction and volatile oil, the seizure intensity decreased significantly after treatment. Increased GABA-IR neurons also were found when compared with PTZ kindling controls. Morphologic observation also showed that GABA-IR neuron damage was less severe in the drug-treated groups. CONCLUSIONS: Both decoction and volatile oil extracted from the rhizome of Acorus tatarinowii Schott have anticonvulsive effects. The volatile oil is shown to be less effective for PTZ-induced convulsions. Both extracts can prevent convulsions as well as convulsion-related GABAergic neuron damage in the brain in the prolonged PTZ kindling model.

Acorus↗
PubMed2005

Quantitative transcriptional profiling of ATDC5 mouse progenitor cells during chondrogenesis.

During the differentiation of a mouse chondroprogenitor cell line, ATDC5, an analysis of the transcription cartilage-related genes was carried out using real-time RT-PCR in a semiquantitative fashion. A total number of 104 genes both previously linked to chondrogenesis and hitherto not associated with the development of cartilage were analyzed. Parametric statistics, and unsupervised hierarchical and K-medians clustering approaches were used to analyze the gene expression during the sequential processes of proliferation, condensation, differentiation, maturation, and hypertrophic conversion of ATDC5 cells. The obtained data provided a robust determination of expression patterns that make possible an accurate assessment of the molecular events along the chondrogenic differentiation pathway. In addition, time-course expression profiles were described for eight highly regulated genes that have not been associated with chondrogenesis as yet. These included Cryab, Rcor2, Hig1, Bnip3, Mst4, Calml4, Gng2, and Islr.

Animals↗
PubMed2005

Proteasome-mediated degradation of cotranslationally damaged proteins involves translation elongation factor 1A.

Rad23 and Rpn10 play synergistic roles in the recognition of ubiquitinated proteins by the proteasome, and loss of both proteins causes growth and proteolytic defects. However, the physiological targets of Rad23 and Rpn10 have not been well defined. We report that rad23Delta rpn10Delta is unable to grow in the presence of translation inhibitors, and this sensitivity was suppressed by translation elongation factor 1A (eEF1A). This discovery suggested that Rad23 and Rpn10 perform a role in translation quality control. Certain inhibitors increase translation errors during protein synthesis and cause the release of truncated polypeptide chains. This effect can also be mimicked by ATP depletion. We determined that eEF1A interacted with ubiquitinated proteins and the proteasome following ATP depletion. eEF1A interacted with the proteasome subunit Rpt1, and the turnover of nascent damaged proteins was deficient in rpt1. An eEF1A mutant (eEF1A(D156N)) that conferred hyperresistance to translation inhibitors was much more effective at eliminating damaged proteins and was detected in proteasomes in untreated cells. We propose that eEF1A is well suited to detect and promote degradation of damaged proteins because of its central role in translation elongation. Our findings provide a mechanistic foundation for defining how cellular proteins are degraded cotranslationally.

Adenosine Triphosphate↗
PubMed2005

hnRNP K binds a core polypyrimidine element in the eukaryotic translation initiation factor 4E (eIF4E) promoter, and its regulation of eIF4E contributes to neoplastic transformation.

Translation initiation factor eukaryotic translation initiation factor 4E (eIF4E) plays a key role in regulation of cellular proliferation. Its effects on the m7GpppN mRNA cap are critical because overexpression of eIF4E transforms cells, and eIF4E function is rate-limiting for G1 passage. Although we identified eIF4E as a c-Myc target, little else is known about its transcriptional regulation. Previously, we described an element at position -25 (TTACCCCCCCTT) that was critical for eIF4E promoter function. Here we report that this sequence (named 4EBE, for eIF4E basal element) functions as a basal promoter element that binds hnRNP K. The 4EBE is sufficient to replace TATA sequences in a heterologous reporter construct. Interactions between 4EBE and upstream activator sites are position, distance, and sequence dependent. Using DNA affinity chromatography, we identified hnRNP K as a 4EBE-binding protein. Chromatin immunoprecipitation, siRNA interference, and hnRNP K overexpression demonstrate that hnRNP K can regulate eIF4E mRNA. Moreover, hnRNP K increased translation initiation, increased cell division, and promoted neoplastic transformation in an eIF4E-dependent manner. hnRNP K binds the TATA-binding protein, explaining how the 4EBE might replace TATA in the eIF4E promoter. hnRNP K is an unusually diverse regulator of multiple steps in growth regulation because it also directly regulates c-myc transcription, mRNA export, splicing, and translation initiation.

Animals↗
PubMed2005

Identification and analysis of U5 snRNA variants in Drosophila.

Distinct isoforms of spliceosomal RNAs may be involved in regulating pre-messenger RNA splicing in eukaryotic cells. During a large-scale effort to identify small noncoding RNAs in Drosophila, we isolated a U5 snRNA-like molecule containing a 5' segment identical to that of the canonical (major) U5 snRNA but with a variant Sm binding site and a distinct 3' hairpin sequence. Based on this finding, another six similar U5 snRNA-like sequences were identified within the Drosophila genome by sequence similarity to the invariant loop in the 5' half of U5. Interestingly, although all of these variants are expressed in vivo, each shows a distinct temporal expression profile during Drosophila development, and one is expressed primarily in fly heads. The presence of these U5 snRNA variants within RNP particles suggests their role in splicing and implies a possible connection to regulation of developmental and tissue-specific gene expression.

Amino Acid Sequence↗
PubMed2005

Effect of molecular mass on antitumor activity of heteropolysaccharide from Poria cocos.

A water-soluble heteropolysaccharide ac-PCM0 from Poria cocos was successfully fractionated using a preparative size exclusion chromatography (SEC) column, and their weight-average molecular mass (M(w)) was characterized by analytical SEC combined with laser light scattering (SEC-LLS). The results indicate that the fractions having relatively high M(w) exhibited higher inhibition ratio in vivo antitumor activity than those having M(w) below 3.29 x 10(4). However, the relatively low molecular mass was beneficial to the in vitro antitumor activity. Moreover, ac-PCM0 has a significantly higher enhancement ratio of the body weight than 5-fluorouracil, and its 50% lethal dose is above 1250 mg/kg, indicating a nontoxic nature.

Animals↗
PubMed2005

Surgical management of gastric stump cancer: a report of 37 cases.

OBJECTIVE: To observe the clinicopathological characteristics of gastric stump cancer (GSC) and evaluate the benefits of radical surgery of GSC. METHODS: The clinicopathological characteristics and postoperative survival time of 37 GSC patients who underwent surgery were investigated retrospectively. The survival time was compared according to the type of surgical operation (radical resection vs palliative operation). Twenty-one cases that received radical resection were analyzed based on the pTMN stage. Survival curves were traced by using Kaplan-Meier methods. RESULTS: Most GSC (32/37) was detected in patients who had received Billroth II reconstruction after partial gastrectomy for benign gastric disease. The lesser curvature side and the suture line of anastomosis were the most frequent sites where GSC occurred (27/37). Differentiated adenocarcinoma was the dominant histopathological type (24/37). The postoperative 5-year survival rate of early stage GSC patients (n=9) was significantly higher than advanced stage GSC (n=12) (55.6% vs 16.5%, xL2=11.48, P<0.01). Five-year survival rate of 21 GSC patients with radical resection were 75% (3/4) for stage I, 60% (3/5) for stage II, 14.2% (1/7) for stage III, and 0% (0/5) for stage IV respectively. The median survival time of 21 GSC patients who underwent radical resection was longer than those undergoing palliative operation (43.0 m vs 13.0 m, x L2=36.31, P<0.01), the median survival time of stage IV patients with radical resection was 23.8 months. CONCLUSIONS: Without remote metastasis, radical resection for GSC is possible, and is an effective way to improve the prognosis of GSC. Even in stage IV GSC, radical resection can still prolong the survival time. It is necessary for the patients with benign gastric diseases who received partial gastrectomy to carry out the endoscopy follow-up, especially in patients with Billroth II reconstruction procedure at 15-20 years.

Aged↗
PubMed2005

Patients' quality of life after laparoscopic or open cholecystectomy.

OBJECTIVE: This study was aimed at evaluating and comparing the quality of life in patients who underwent laparoscopic and open cholecystectomy for chronic cholecystolithiasis. METHODS: The study included 25 patients with laparoscopic cholecystectomy (LC group) and 26 with open cholecystectomy (OC group). The quality of life was measured with the Gastrointestinal Quality of Life Index (GLQI) preoperatively, thereafter regularly at 2, 5, 10 and 16 weeks after the operation. RESULTS: The mean preoperative overall GLQI scores were 112.5 and 110.3 in LC and OC group respectively (P>0.05). In the LC group, the mean overall GLQI score reduced slightly to 110.0 two weeks after the operation (P>0.05). The LC group showed significant improvement in overall score and in the aspects of symptomatology, emotional and physiological status from 5 to 16 weeks postoperatively. In the OC group, the GLQI score reduced to 102.0 two weeks after surgery (P<0.05). Significant reductions were shown in the aspects of symptomatology, physiological and social status. The GLQI scores returned to the preoperative level of 115.6 ten weeks after the operation (P>0.05). The patients experienced significant improvements of GLQI sixteen weeks after OC operation (P<0.01~0.05). Within the 10 postoperative weeks, the LC group had significantly higher GLQI scores than the OC group (P<0.05). CONCLUSIONS: LC can improve the quality of life postoperatively better and more rapidly than OC. The assessment of quality of life assessment is a valid method for measuring the effects of surgical treatment.

Adult↗
PubMed2005

Role of CD97(stalk) and CD55 as molecular markers for prognosis and therapy of gastric carcinoma patients.

OBJECTIVES: To explore the mechanism of development and aggressiveness in gastric carcinomas by investigating the expression and role of CD97 and its cellular ligand CD55 in gastric carcinomas. METHODS: Tumor and corresponding normal mucosal tissue, collected from 39 gastric carcinoma patients, were examined by immunohistochemistry and RT-PCR for the expression of CD97 and CD55. RESULTS: CD97(stalk) was strongly stained on scattered tumor cells or small tumor cell clusters at the invasion front of gastric carcinomas. The expression of CD97(stalk) was frequently observed in tumors of stage I and T1 gastric carcinoma patients. The expression of CD97(stalk) between Stage I and Stage II, III, IV specimens showed significant difference (P<0.05), between T1 and T2, T3, T4 specimens also showed significant difference (P<0.05). Specimens with tumor invasion depth limited in mucosa of T1 specimens showed higher positive CD55 expression than specimens with the same tumor invasion depth in T2, T3, T4 specimens, the expression of CD55 between T1 and T2, T3, T4 specimens was significantly different (P<0.05). There was strong correlation between the distribution patterns of CD97(stalk) and CD55 on tumor tissues (r=0.73, P<0.05). Signet ring cell carcinomas frequently contained strong CD97(stalk) and CD55-staining. CONCLUSIONS: Our results suggest that CD97(stalk) is probably involved in the growth, invasion and aggressiveness of gastric carcinomas by binding its cellular ligand CD55. CD97(stalk) and CD55 could be useful as molecular markers for prognosis and therapy of gastric carcinoma patients.

Antigens, CD↗
PubMed2005

[Determination of interleukine-16 levels in peritoneal fluid and serum of women with endometriosis].

OBJECTIVE: To investigate the role of interleukine-16 (IL-16) in the pathogenesis of endometriosis. METHODS: Enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of IL-16 in peritoneal fluid and serum specimens of 22 women with different stage endometriosis and 22 controls. RESULTS: The median levels of IL-16 in peritoneal fluid and serum were 290.5 pg/ml and 539.4 pg/ml in women with endometriosis, and 296.6 pg/ml and 778.1 pg/ml in controls, respectively; there was no significant difference between two groups (P>0.05). However, the IL-16 levels in peritoneal fluid and serum of patients with minimal/mild stage endometriosis and controls were all significantly higher than those of patients with moderate/severe endometriosis (P<0.01, <0.05). In addition, there was no statistical correlation of peritoneal IL-16 levels with those in serum (P>0.05). CONCLUSION: Reduced levels of IL-16 in peritoneal fluid and serum of women with advanced stage endometriosis may imply a role of IL-16 in the development and progression of endometriosis.

Adult↗
PubMed2005

[Investigation on the molecular mechanisms of anti-hepatocarcinoma herbs of traditional Chinese medicine by cell cycle microarray].

OBJECTIVE: To design DNA microarray and investigate the molecular anti-tumor mechanism of herbs of traditional Chinese medicine. METHOD: cDNA microarrays consisting of 56 probes representing 24 human cell cycle genes were constructed, Four anti-hepatocarcinoma herbs including Radix Linderae, Hebra Artemisiae Annuae, Radix Amebiae, Radix Astragli, were chosen. Effects of herbs on SMMC-7721 cell cycle were observed by flow cytometry assay. Effects of herbs on cell cycle gene expression in SMMC-7721 cells were analyzed by comparing hybridization of Dig-Labeled cDNAs from herb-treated cells and cDNAs from untreated cells. RESULT: Expressions of cell cycle geneswere changed in different degrees after herbs treated. Some genes were down-regulated and some genes were up-regulated. The changes in gene expression agreed with the results of flow cytometry assay. CONCLUSION: The results suggest that these herbs may have effects on cell cycle and DNA damage checkpoint genes which may be the mechanism of the herbs, and DNA microarray can be used to investigate the biological function of extracts of traditional Chinese medicine.

Antineoplastic Agents, Phytogenic↗
PubMed2005

[Superfine comminution of Glycyrrhiza uralensis roots by vibration mill].

OBJECTIVE: To discuss the mechanism of superfine comminution of traditional Chinese medicine (TCM) at low temperature. METHOD: Glycyrrhiza uralensis roots were at room superfinely comminuted temperature and at low temperature by cryogenic vibration mill. The superfine powders were observed and analyzed by laser particle size analyzer and SEM. RESULT: The powder processed at low temperature was of smaller effective diameter and narrower size distribution and was also with smoother surface and smaller angle of repose. CONCLUSION: The G. uralensis roots could be superfinely comminuted with high efficiency and simple procedure by vibration mill at low temperature.

Glycyrrhiza uralensis↗
PubMed2005

[Clinical anatomy study of olfaction correlative nerves].

OBJECTIVE: To find out the relation of the olfactory nerves, the optic nerve, and the nasal sinuses. Provide anatomic data for not to damnify olfactory nerves in the surgery. METHOD: To measure the olfactory nerves, the olfactory bulb, and olfactory tract on 16 adult cadaveric specimens, and observe the relation of the olfactory nerves, the optic nerve,and the nasal sinuses. RESULT: Length of the olfactory tract was (29.32 +/- 2.11) mm, width of the olfactory tract was (3.36 +/- 0.83) mm. The distance from the midpoint of the olfactory tract to the midline of the skull was (5.48 +/- 1.02) mm. The angle between olfactory tract and midline of the skull was (21.32 +/- 3.28) degrees. Length of the olfactory bulb was (10.43 +/- 2.35) mm, width of the olfactory bulb was (5.12 +/- 0.62) mm. 27/32 olfactory tracts were border upon with sphenoid sinus and ethmoid sinus, 3/32 olfactory tracts were border upon with ethmoid sinus, 2/32 olfactory tracts were border upon with frontal sinus. All olfactory tracts crossed the optic nerve at the internal meatus of optic nerve canal. The olfactory bulb and ethmoid bulb were on equal line. CONCLUSION: Almost all olfactory tracts were lied in the inboard of the orbital cavity, protect the roof of the nasal sinus to avoid damnify the olfactory nerves. It is easy to pull out the olfactory nerves when raising the cerebra in the operation of anterior cranial fossae.

Adult↗
PubMed2005

[Synthesis and antibacterial activity of ciprofloxacin derivatives].

AIM: To study the synthesis and antibacterial activity of ciprofloxacin derivatives. METHODS: Ciprofloxacin derivatives were synthesized primarily from 2-methyl-5-nitroimidazol and ciprofloxacin through nucleophilic substitution. The antibacterial activity of the synthesized compounds were tested. RESULTS: Nine new compounds were synthesized. The structure of the title compounds were confirmed by 1H NMR, MS and element analysis. CONCLUSION: Compounds II, IVC and IVD showed appreciable antibacterial activity, and were worth further studying.

Animals↗