Biomedical subjects

Li Zhang

Publications and source records attributed to Li Zhang.

At least 235 records · Page 13Linked to original sources

PubMed2006

[Laryngeal electromyographic characteristics of vocal fold immobility].

OBJECTIVE: To investigate the characteristics of laryngeal electromyography and evoked electromyography in vocal fold immobility. METHODS: 108 cases of vocal fold immobility were analyzed by clinical manifestation and laryngeal electromyography characteristics, including spontaneous potential activity, motor unit potential (MUP) measurement, recruitment pattern analysis and evoked electromyography evaluation. RESULTS: Neurogenic vocal fold immobility showed a wide variety of abnormal activity. Fibrillation potentials and positive sharp waves were found in patients with laryngeal nerve injuries. For laryngeal paralysis, there was no reaction with LEMG and evoked LEMG. For laryngeal paresis, it showed decreased MUP and decreased recruitment activities with simple pattern recruitment or mixed pattern recruitment, and decreased evoked muscle response potentials were also shown with delayed latency than normal (P < 0.05) in the TA (2.2 +/- 1.0) ms(x +/- s), PCA (2.4 +/- 1.0) ms and lower amplitude in the TA (0.9 +/- 0.7) mV and PCA (1.2 +/- 1.0) mV (P < 0.05). Patients with vocal fold mechanical limitations generally yielded normal LEMG and Evoked LEMG. Patients with neoplastic infiltration of the laryngeal muscles demonstrated decreased LEMG and nearly normal Evoked LEMG with normal latency and lower amplitude. CONCLUSIONS: General EMG and evoked EMG play a crucial role in the diagnosis of vocal fold immobility.

Adolescent↗

PubMed2006

[Drug release mechanism of famotidine time-controlled release pellets].

AIM: To study the drug release mechanism of famotidine time-controlled release pellets and to explore the mechanism of "organic acid-induced type drug delivery system". METHODS: The effects of dissociated and undissociated forms of succinic acid on the drug release behavior of famotidine time-controlled release pellets were studied from the following aspects: ion-exchange reaction, hydration, etc. RESULTS: The dissociated succinic acid created new ionic circumstances by ion-exchange reaction with Eudragit RS100. Whereas undissociated succinic acid increased the flexibility of the film by distribution in the hydrophobic segment of Eudragit RS100. Effects of both forms of the succinic acid could improve the hydration of Eudragit RS film. As a result, the permeability of the film was improved evidently. CONCLUSION: The lag time of famotidine time-controlled release pellets is induced by the hydrophobicity of the film. After water dissolve the organic acid, the dissociated and undissociated forms of succinic acid interact with the film through different ways. These interactions can change the structure of the film. Therefore the permeability of the film will be improved markedly.

Acrylic Resins↗

PubMed2006

[FTIR spectroscopic characterization of freshly removed breast cancer tissues].

OBJECTIVE: To identify the FTIR spectroscopic characterization of breast cancer and explore the possibility of application of FTIR in differentiation of malignant and benign breast lesions. METHODS: FTIR spectra of surgically removed fresh breast tissues were measured by spectrometer equipped with mid-infrared fiber optics and an ATR probe. Peaks in the spectra were measured and relative intensity ratios were calculated and analyzed if there are significant differences between the spectra of malignant and benign breast lesions. RESULTS: There were significant differences (P < 0.05) between the spectra of malignant breast cancers and benign breast tissues in the relative intensity ratios of different peaks (I1640/ I1550 and I1160/I1120 for protein structures; I1640/I1460 and I1550/I1460 for relative content of protein and lipid; I1460/I1400 for lipid structures; I1310/I1240 for nucleic acid). CONCLUSION: FTIR spectroscopy could be a useful tool in clinical diagnosis of breast cancer.

Adolescent↗

PubMed2006

[Transbronchial needle aspiration in the diagnosis of bronchogenic carcinoma with enlarged mediastinal and /or hilar lymph nodes].

OBJECTIVE: To evaluate the role of transbronchial needle aspiraion (TBNA) in the diagnosis of bronchogenic carcinoma with enlarged mediastinal and/or hilar lymph node. METHODS: Patients with mediastinal and/or hilar lymphoadenopathy proven by CT scan were eligible for TBNA as reported by WANG. All specimen was directly and instantly smeared for cytological examination. RESULTS: From June 2004 to May 2006, 77 such patients were examined: including 38 lung cancers, 35 lung benign diseases and 4 without definite diagnosis. All TBNA procedures were successfully carried out in 222/225 ( 98.7%). Positive TBNA rate was 81.6% (31/38) in patients who had been proven to suffer from bronchogenic carcinoma. The diagnosis of lung cancer was confirmed via TBNA only in 9 patients. A total of 63 lymph nodes in the 38 lung cancer patients were aspirated by TBNA with a positive rate of 65.1% (41/63). The sensitivity of TBNA was significantly correlated with pathology type, lymph node size and experience of the cytologist. Severe complications were rare except small amount of bleeding at the TBNA site (52/77, 67.5%). CONCLUSION: TBNA is quite safe and helpful in diagnosis and staging of bronchogenic carcinoma, yet it is not helpful in diagnosis of benign lung diseases.

Adolescent↗

PubMed2006

[Gefitinib in the treatment of advanced non-small-cell lung cancer].

OBJECTIVE: To study the anti-tumor effect and toxicity of Gefitinib in the treatment of patients with advanced non-small-cell lung cancer (NSCLC). METHODS: From August 2003 to February 2005, 50 advanced NSCLC patients were treated with Gefitinib orally 250 mg once per day. All patients were stratified by gender, histology, smoking history and chemotherapy cycles. The response was evaluated as the time to tumor progression (TTP) and the median survival time (MST). Quality of life (QoL) was assessed using the Chinese version of European Organization for Research and Treatment of Cancer (EORTC) core questionnaire QLQ-30 and the brief fatigue inventory (BFI). RESULTS: Even though none of these patients achieved complete response, 16.0% of them still gave partial response. Clinical benefit rate was 60.0% in this series. Objective tumor response was correlated with gender, pathological type and smoking history. Multivariate analysis suggested that gender, chemotherapy cycles and QoL obviously correlated with the tumor response. Twenty of these 50 patients (40.0%, 20/50) were still alive when the follow-up ended in February 2005. The 1-year survival rate was 14.0%. TTP and MST was 5 and 6 months, respectively, in patients who had been dead. The median survival time of patients who are still alive was 13 months. The mean survival time of PR patients was more than 9 months. The rate of QoL improvement was 58.0% and the rate of fatigue remission was 52.6%. The mean time to symptom improvement was 15 days. The main toxicities were reversible grade I or grade II skin rash and diarrhea. Two patients who developed radiation pneumonitis during previous radiotherapy became more deteriorated after Gefitinib treatment. CONCLUSION: Gefitinib is effective and tolerated by the patients with advanced non-small cell lung cancer. It may remarkablely improve their symptoms and quality of life.

Antineoplastic Agents↗

PubMed2006

[Influence of propofol on Gq/11 protein in kidney during acute respiratory distress syndrome].

OBJECTIVE: To explore whether propofol plays a protective role in kidney injury during acute respiratory distress syndrome (ARDS) by affecting the expression of Gq/11 protein. METHODS: An ARDS model in rats was reproduced by intravenous injection of oleic acid (OA). Healthy Wistar rats were randomly divided into pre-treatment group in which rats received propofol before given OA (P group), OA group with rats received propofol 90 minutes after iv OA (OA group) and control group (C group). Blood pressure, plasma and kidney homogenate contents of angiotensin-conversion enzyme (ACE), lactate dehydrogenase (LDH) activity and malondialdehyde (MDA) were assessed during the experimental period, and the concentration of Gq/11 protein was determined by Western blot. RESULTS: The concentration of Gq/11 protein of P group [(124.68+/-19.38)%] was increased (24.68+/-19.38)% compared with C group [(100.00+/-0)%, P<0.01], and it was obviously decreased compared with OA group [(149.34+/-20.04)%, P<0.01]. ACE [(16.52+/-1.37) micromol x min(-1)xg(-1)], LDH activity [(1.20+/-0.16) kU/g] and MDA content [(1.51+/-0.35) micromol/g], respectively, in homogenate of P group were lower than OA group [(17.56+/-1.02) micromol x min(-1)xg(-1), (1.41+/-0.16) kU/g, (1.94+/-0.16) micromol/g, respectively, all P<0.01]. CONCLUSION: Pre-treatment with propofol can reduce the concentration of Gq/11 protein in kidney tissue, and it can ameliorate the injury to the kidney during ARDS.

Animals↗

PubMed2006

[Efficacy of gefitinib on advanced non-small cell lung cancer in expanded access program (EAP)].

BACKGROUND & OBJECTIVE: Gefitinib is a selective inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, and has been used in treating advanced non-small cell lung cancer (NSCLC). This study was to evaluate the efficacy of Gefitinib on advanced NSCLC, and observe adverse events. METHODS: An open labeled, expanded access program (EAP) was conducted. Pathologically confirmed advanced NSCLC patients who had progressed after systemic chemotherapy or was not suitable for systemic chemotherapy were eligible for this program. Gefitinib (250 mg) was orally administered daily till disease progression or intolerable adverse events developed. RESULTS: From Sep. 2002 to Mar. 2005, 120 patients were enrolled, and 103 of them were assessable for response. The objective response rate was 18.4% (19/103). The disease control rate was 51.5% (53/103). The median survival time was 6 months (0.5-33 months). Adverse events were generally mild (grade I or II), including skin rash (30.1%), dry skin (12.6%), and diarrhea (25.2%). Two (1.9%) patients developed grade III elevation of serum glutamate pyruvate transaminase (SGPT). No grade IV adverse event occurred. CONCLUSION: Gefitinib is effective in treating advanced NSCLC, and the adverse events are mild.

Adenocarcinoma↗

PubMed2006

[Levels of intracellular IL-6 and IFN-gamma in children with acute lymphoblastic leukemia].

OBJECTIVE: To study the changes of intracellular interleukin-6 (IL-6) and interferon-gamma (IFN-gamma) expressions in children with acute lymphoblastic leukemia (ALL) at different stages, and to examine the correlation between IL-6 and IFN-gamma in ALL children. METHODS: The levels of intracellular IL-6 and IFN-gamma in venous blood lymphocytes were detected by flow cytometry in 42 children with ALL at diagnosis and at remission stage. Twenty healthy children were used as the controls. RESULTS: The intracellular IL-6 level in ALL children at diagnosis was 81.74+/-9.31, which was much higher than that in the Control group (5.67 +/- 0.96 ) (P < 0.01). The intracellular IFN-gamma level in ALL children (1.31 +/- 0.32) was significantly lower than that in the Control group (1.46 +/- 0.49) (P < 0.01). However, the intracellular IL-6 level (27.52 +/- 3.40) decreased remarkably in ALL patients at remission stage (P < 0.01), but was still higher than that in the Control group (P < 0.01). In contrast, the intracellular IFN-gamma level (1.97 +/- 0.72) increased noticeably in ALL patients at remission stage, which was higher than that at diagnosis and the Control group (P < 0.01). A negative correlation was found between the intracellular IL-6 and the IFN-gamma levels in ALL patients (r=-0.476, P < 0.05). CONCLUSIONS: Intracellular IL-6 and IFN-gamma levels may be used as the markers for monitoring the response to treatment in ALL patients. There is a negative correlation between intracellular IL-6 and IFN-gamma levels in ALL children.

Adolescent↗

PubMed2006

[Changes of heart function after different cell type stem cell transplantation in chronic heart failure].

To investigate the feasibility of introcoronary cell infusion into nonischemic heart failure (HF) heart and whether different types of stem cell transplantation would affect heart function to a similar degree. Japanese white ears rabbits were used as HF models by intravenous injection adriamycin. Autologous bone marrow mononuclear cells(BMCs), bone marrow stromal cells (MSCs), skeletal myoblasts (SMs) or culture medium were infused into coronary arteries respectively by occluding the root of ascending aorta. The mortality during and 4 weeks after the procedure the mortality was 7.1% and 16.7% respectively. After 4 weeks, the ejection fraction (EF) in BMCs group had significant improvement (P < 0.05, n=8). No significant difference was seen in MSCs (n =8), SMs (n=6) and sham groups (n=8) compared with pretransplantation (P > 0.05). In sham group,the left ventricular endostolic diameter (LVED) had significant enlargement (P < 0.05), No significant difference was seen in MBCs, MSCs and SMs groups compared with pretransplantation (P > 0.05). Immunofluorescence revealed de novo expression of cardiac troponin I in BMCs and MSCs groups, cardiac troponin I was not detected in SMs group. In conclusions, intracoronary cell transplantation could provide effective cell delivery into dilated cardiomyopathy hearts and could be a useful strategy for treating CHF, BMCs cell transplantation may be the first choice in all the above cell types.

Animals↗

PubMed2005

Trak1 mutation disrupts GABA(A) receptor homeostasis in hypertonic mice.

Hypertonia, which results from motor pathway defects in the central nervous system (CNS), is observed in numerous neurological conditions, including cerebral palsy, stroke, spinal cord injury, stiff-person syndrome, spastic paraplegia, dystonia and Parkinson disease. Mice with mutation in the hypertonic (hyrt) gene exhibit severe hypertonia as their primary symptom. Here we show that hyrt mutant mice have much lower levels of gamma-aminobutyric acid type A (GABA(A)) receptors in their CNS, particularly the lower motor neurons, than do wild-type mice, indicating that the hypertonicity of the mutants is likely to be caused by deficits in GABA-mediated motor neuron inhibition. We cloned the responsible gene, trafficking protein, kinesin binding 1 (Trak1), and showed that its protein product interacts with GABA(A) receptors. Our data implicate Trak1 as a crucial regulator of GABA(A) receptor homeostasis and underscore the importance of hyrt mice as a model for studying the molecular etiology of hypertonia associated with human neurological diseases.

Adaptor Proteins, Vesicular Transport↗

PubMed2005

Lead zinc borate, PbZn2(BO3)2.

PbZn2(BO3)2 crystallizes in the space group Pccn, with the Pb cation at a site with imposed twofold symmetry. The compound represents a new structure type in which ZnBO3 layers are bridged by Pb2+ cations, giving rise to a three-dimensional framework. Channels parallel to the [010] direction accommodate the stereochemically active lone pairs of the Pb2+ cations.

Journal Article↗

PubMed2005

Position preference on glucuronidation of mono-hydroxylflavones in human intestine.

Extensive intestinal glucuronidation has been previously reported in both human and animals after oral administration of naturally occurred flavonoids. The present study aims to investigate the relationship between human intestinal glucuronidation activity and the position of hydroxyl substitution on flavonoids. Seven commercially available mono-hydroxyflavones (HF), namely 3-, 5-, 6-, 7-, 2'-, 3'- and 4'-mono-hydroxyflavones, were chosen as model compounds. Glucuronidation activity of the selected seven HFs was investigated by incubating each HF at various concentrations with human jejunum S9 at 37 degrees C for 10 min. The generated glucuronides were identified by HPLC/MS and quantified by HPLC/UV. Metabolic kinetics parameters including Km and Vmax of each HF were determined. The results demonstrated that the glucuronidation activity of 6- and 3'-mono-hydroxyflavones was much greater than that of 3-, 4'-, 7- and 2'-HF with 5-HF to be the lowest. The findings imply that nucleophilicity and stereo-conformation of OH substituents are crucial for the intestinal glucuronidation of flavonoids.

Biological Availability↗

PubMed2005

Fluid structure and transport properties of water inside carbon nanotubes.

The fluid structure and transport properties of water confined in single-walled carbon nanotubes (CNTs) with different diameters have been investigated by molecular-dynamics simulation. The effects of CNT diameter, density of water, and temperature on the molecular distributions and transport behaviors of water were analyzed. It is interesting that the water molecules ordered in helix inside the (10, 10) CNT, and the layered distribution was clearly observed. It was found that the axial and radial diffusivities in CNTs were much lower than that of the bulk, and it ever decreased as the diameter of CNT decreases. The axial thermal conductivity and shear viscosity in CNTs are obviously larger than that of the bulk and those in the radial direction, they increase sharply as the diameter of CNT decreases, which is clearly in contrast to the diffusivity. The inner space of CNT and the interactions between water molecules and the confining walls play a key role in the structure and transport properties of water confined in the CNTs.

Journal Article↗

PubMed2005

IL-18 induces monocyte chemotactic protein-1 production in macrophages through the phosphatidylinositol 3-kinase/Akt and MEK/ERK1/2 pathways.

Macrophages are activated during an inflammatory response and produce multiple inflammatory cytokines. IL-18 is one of the most important innate cytokines produced from macrophages in the early stages of the inflammatory immune response. Monocyte chemoattractant protein (MCP-1) is expressed in many inflammatory diseases such as multiple sclerosis and rheumatoid arthritis, and its expression is correlated with the severity of the disease. Both IL-18 and MCP-1 have been shown to be involved in inflammatory immune responses. However, it has been unclear whether IL-18 is involved in the induction of MCP-1. This investigation was initiated to determine whether IL-18 can induce MCP-1 production, and if so, by which signal transduction pathways. We found that IL-18 induced the production of MCP-1 in macrophages, which was IL-12-independent and was not mediated by autocrine cytokines such as IFN-gamma or TNF-alpha. We then examined signal transduction pathways involved in IL-18-induced MCP-1 production. We found that IL-18 did not activate the IkappaB kinase/NF-kappaB pathway, evidenced by no degradation of IkappaBalpha and no translocation of NF-kappaB p65 to the nucleus in IL-18-stimulated macrophages. Instead, IL-18 activated the PI3K/Akt and MEK/ERK1/2 pathways. Inhibition of either of these pathways attenuated MCP-1 production in macrophages, and inhibition of both signaling pathways resulted in the complete inhibition of MCP-1 production. On the basis of these observations, we conclude that IL-18 induces MCP-1 production through the PI3K/Akt and MEK/ERK1/2 pathways in macrophages.

Animals↗

PubMed2005

Gene expression profiling of localized esophageal carcinomas: association with pathologic response to preoperative chemoradiation.

PURPOSE: Patients with localized esophageal carcinoma have a 5-year survival rate of less than 20%. Patients are often treated similarly (ie, with preoperative chemoradiotherapy) but the outcomes vary greatly. Chemoradiotherapy and surgery can result in significant undesirable consequences. Currently, however, there are no tools to help select optimum therapy. We hypothesized that gene expression profiling could provide clues and biomarkers for selection of therapy. METHODS: Pretreatment endoscopic cancer biopsies from 19 patients (16 with adenocarcinoma, two with squamous cell carcinoma, and one with adenosquamous carcinoma) enrolled onto a preoperative chemoradiotherapy protocol were profiled using oligonucleotide microarrays. Surgical specimens following therapy were assessed for the degree of pathologic response. On the basis of array data, selected genes were analyzed by polymerase chain reaction. RESULTS: Unsupervised hierarchical cluster analysis segregated the cancers into two molecular subtypes, each consisting 10 and nine specimens, respectively. Most cancers (five of six) that had pathologic complete response (pathCR) clustered in molecular subtype I. Subtype II, with one exception, consisted cancers that had less than pathCR (< pathCR). Using a combination marker approach, levels of PERP, S100A2, and SPRR3 allowed discrimination of pathCR from < pathCR with high sensitivity and specificity (85%). Pathway analysis identified apoptotic pathway as one of the key functions downregulated in molecular type II in comparison with type I. CONCLUSION: These encouraging, albeit preliminary, data suggest that expression profiling may distinguish cancers with different pathologic outcome. This is the first report to show subtypes of esophageal cancers with distinct molecular signatures. The potential of PERP, S100A2, and SPRR3 as biomarkers of pathCR warrants further validation.

Adenocarcinoma↗

PubMed2005

Addition of grignard reagents to aryl acid chlorides: an efficient synthesis of aryl ketones.

[chemical reaction: see text]. Direct addition of Grignard reagents to acid chlorides in the presence of bis[2-(N,N-dimethylamino)ethyl] ether proceeds selectively to provide aryl ketones in high yields. A possible tridentate interaction between Grignard reagents and bis[2-(N,N-dimethylamino)ethyl] ether moderates the reactivity of Grignard reagents, preventing the newly formed ketones from nucleophilic addition by Grignard reagents.

Journal Article↗

PubMed2005

Gene sequence signatures revealed by mining the UniGene affiliation network.

BACKGROUND: In the post-genomic era, developing tools to decode biological information from genomic sequences is important. Inspired by affiliation network theory, we investigated gene sequences of two kinds of UniGene clusters (UCs): narrowly expressed transcripts (NETs), whose expression is confined to a few tissues; and prevalently expressed transcripts (PETs) that are expressed in many tissues. RESULTS: We explored the human and the mouse UniGene databases to compare NETs and PETs from different perspectives. We found that NETs were associated with smaller cluster size, shorter sequence length, a lower likelihood of having LocusLink annotations, and lower and more sporadic levels of expression. Significantly, the dinucleotide frequencies of NETs are similar to those of intergenic sequences in the genome, and they differ from those of PETs. We used these differences in dinucleotide frequencies to develop a discriminant analysis model to distinguish PETs from intergenic sequences. CONCLUSIONS: Our results show that most NETs resemble intergenic sequences, casting doubts on the quality of such UniGene clusters. However, we also noted that a fraction of NETs resemble PETs in terms of dinucleotide frequencies and other features. Such NETs may have fewer quality problems. This work may be helpful in the studies of non-coding RNAs and in the validation of gene sequence databases.

Animals↗

PubMed2005

Dynamics and density profile of water in nanotubes as one-dimensional fluid.

The transport and structural properties of water confined in nanotubes with different diameters were studied by molecular dynamics (MD) simulation. The effects of pore size, molecule-wall interaction, and the helicity of CNT on the diffusivity, thermal conductivity, and shear viscosity as well as density profile were analyzed. For diffusivity, in model NT > in armchair CNT > in zigzag CNT at similar conditions. However in contrast to the diffusivity, the thermal conductivity and the shear viscosity increase as the pore size decreases, in zigzag CNT > in armchair CNT > (or approximately ) in model NT. The ordered layer distribution of water molecules in nanotubes is clear. It suggests the structure of fluid in the zigzag CNTs is more ordered, and more solidlike. In the nanotubes, where the molecule and the pore dimensions are of similar order of magnitude, the nature of water-water and water-wall interactions, the confinement effect of space, and the helicity of CNT become more significant.

Molecular Dynamics Simulation↗