Biomedical subjects

Lin Li

Publications and source records attributed to Lin Li.

At least 181 records · Page 10Linked to original sources

PubMed2004

[Effects of Capsule Yizhi on the delayed neuronal death in hippocampal CA1 region and memory function after global cerebral ischemia in rats].

OBJECTIVE: To observe the effects of Capsule Yizhi on the delayed neuronal death in hippocampal CA1 region and memory function after global cerebral ischemia in rats. METHODS: The model of acute reperfusion injury after cerebral ischemia in rats was made by vertebral and carotid arteries occlusion. 1,2,4,8 and 40 days later, the neurons in hippocampal CA1 region were immunohistochemically stained and calculated. And the Morris water maze test was carried out to observe the learning and memory capacities in the 40th day. RESULTS: The number of normal neurons was significantly higher in Capsule Yizhi (100 mg/kg) group than that in the control group. Compared with the control group, Capsule Yizhi (100 mg/kg) could significantly shorten time in finding the platform under the water surface in Morris water maze test. CONCLUSION: Capsule Yizhi had protective effects on neurons in hippocampal CA1 region,and presented promising effects on learning and memory dysfunction after global ischemia/reperfusion injury.

Animals↗

PubMed2004

[Potential effect of tumor necrosis factor-alpha and tumor necrosis factor receptor II gene polymorphisms on the pathogenesis of silicosis].

OBJECTIVE: To approach the role of tumor necrosis factor-alpha (TNF-alpha) and tumor necrosis factor receptor II (TNFR II) gene polymorphisms in genetic susceptibility to silicosis and their interaction with silica-dust exposure. METHODS: Two hundred and fifty-nine cases of silicosis and three hundred and forty-one silica-dust exposure workers (control) were selected, and the cases of silicosis were divided into three subgroups based on the various stages of I, II and III. Exposure history, pneumoconiosis history and past history of each subject were obtained by questionnaire. 3 ml peripheral venous blood was drawn from each subject. Using polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) techniques, TNF-alpha and TNFRII gene polymorphisms were analyzed. RESULTS: In both group matching and 1:1 paired matching, there was no significant difference between cases of silicosis and workers in control in distribution frequencies of G/A + A/A (TNF-alpha-308) and T/G + G/G (TNFRII 196) genotypes. The risk of silicosis in those with G/A + A/A genotype was 6.74-fold higher than G/G genotype (OR = 6.74, 95% CI: 1.01 approximately 44.99) in subjects whose exposure time was less than 15 years. CONCLUSION: TNF-alpha and TNFR II gene polymorphisms did not play an important role in susceptibility to silicosis of Han race. There was interaction between polymorphism of TNF-alpha gene promoter and exposure time in the occurrence of silicosis. The risk of silicosis in those with G/A + A/A genotype was significantly higher than G/G genotype in low accumulative exposure.

Adult↗

PubMed2004

[A study on the variation in classifying chest radiographs for pneumoconiosis].

OBJECTIVE: To study the interobserver variation and its sources in classifying chest radiographs of pneumoconiosis for improving diagnostic quality. METHODS: A set of 240 high-voltage chest radiographs including different stages of pneumoconiosis was developed and 5 sets of copies were made in the same condition. It was read by 7 experienced readers independently in eligible situation. Results of reading were recorded in unified reading sheets. The profusion of small opacities and the stage of pneumoconiosis were recorded as corresponding numerical value for analysis. RESULTS: The coefficients of variation of 7 readers in total profusion of small opacities, average profusion of small opacities and stage of pneumoconiosis were 15.17%, 15.91%, 12.06%, respectively. The judgement of the presence or absence of small opacities, large opacities and coalescence of small opacities were closer, and the rates of consistency were 91.09%, 91.93% and 76.41% respectively. Technical quality of the radiographs in this study could not make a considerable impact on the reading results. If the shape of small opacities were recorded consistently by most readers as small rounded opacities or small irregular opacities, the judgement of total profusion of small opacities and stage of pneumoconiosis were more consistent; if the shape of small opacities were recorded inconsistently, the difference of judgement was higher. CONCLUSION: Interobserver variation exists actually among different readers and the main sources of the variation come from uncertain judgement of the shape of small opacities.

Humans↗

PubMed2004

[Analysis of codon usage in potato and its application in the modification of t-PA gene].

Bioperl-1.0 was used under Hongqi LINUX system to program the codon analysis software. According to the analysis of 98 codon DNA sequences with this software, the codon usage in potato was calculated and 4 codons have been inferred to the optimal codons. The codons of tissue plasminogen activator (t-PA) gene sequence have been reconstructed according to the results. The t-PA gene sequence containing the optimal codons of potato will be used for t-PA production by potato bioreactor.

Amino Acid Sequence↗

PubMed2004

[Structure and expression analysis of the gama-glutamylcysteine synthetase gene in rice].

Gama-glutamylcysteine synthetase (GCS) is a rate-limiting enzyme in GSH biosynthesis. The GCS gene has been cloned in Arabidopsis thaliana and other plants, but has still not been reported in rice. From rice mutant population generated from T-DNA insertion, we cloned the rice GCS gene from mutant L395 by T-DNA tag cloning method, and named it OsGCS (Genbank accession No. AJ508915). Full length OsGCS cDNA clones were obtained from a rice cDNA library by the PCR method. A comparison of the genome and cDNA sequence (Genbank accession No. AJ508916) shows that OsGCS gene is composed of 15 exons and 14 introns and coding a 493-amino acid protein. The OsGCS gene is highly homologous with the AtGCS gene in the coding region but completely different in the promoter region. The putative transcription start site (TSS) confirmed by RT-PCR was located 211 bp upstream of the translation start codon "ATG". In mutant L395, a single T-DNA copy was integrated between the second intron and second exon of OsGCS gene, causing one nucleotide deletion in the second exon and two nucleotide deletions in the second intron. No significant differences were found in Cd(2+) stress tolerance, rice GCS gene expression level and GSH content between mutant L395 and Zhonghua 11. It is possible that another GCS gene on chromosome 7 might complement function of OsGCS gene on chromosome 5.

Amino Acid Sequence↗

PubMed2004

Signet-ring cell carcinoma of the ampulla of Vater.

Signet-ring cell carcinoma (SRCC) of the alimentary canal is a variant of adenocarcinoma that has a poor clinical prognosis. SRCC of the ampulla of Vater is extremely uncommon with < 12 cases reported in the literature. SRCC of the ampulla of Vater occurs in an older age group (mean age 60 yr) when compared to SRCC of the stomach (under 45 yr), but is similar to SRCC of the large intestine. We report a case of SRCC of the ampulla of Vater with unusual histopathologic features in a 56-yr-old woman who presented with a small tumor at the orifice of the ampulla, associated with extensive lymphovascular invasion and multiple regional lymph node involvement.

Ampulla of Vater↗

PubMed2004

[Cloning and characterization of a full-length HIV-1 genome of a prevalent subtype B-Thai strain in Henan Province].

OBJECTIVE: To clone, identify and phylogenetically characterize a clade B-Thai HIV isolate representing the most prevalent virus in Henan province. METHODS: Peripheral blood mononuclear cells (PBMCs) from an HIV-1 infected patient in Henan Province were separated, and co-cultivated with phytohemagglutinin-stimulated healthy donor PBMCs. Proviral DNA was extracted from productively infected PBMCs. The full-length HIV-1 genome was amplified by using the LA Tag long template PCR system. Primers were positioned in conserved regions within the HIV-1 long terminal repeats. Purified PCR products were T-A ligated into a pWSK29-T vector(CNHN 24 clone). Three recombinant clones containing virtually full-length HIV-1 genome were identified by PCR. The full-length genome was sequenced by using the primer-walking approach. Nucleotide sequence similarities were calculated by the local-homology algorithm. Phylogenetic trees of gag, pol and env reading frames were constructed using the Phylip software. RESULTS: HIV-1 C3V4 sequences indicate that the epidemic in this area was B-Thai subtype. V3 loop multiple amino acid sequence alignments showed amino acid alterations at nine positions. The 9,010 bp genomic sequence derived from isolate CNHN 24 contained all known structural and regulatory genes of an HIV-1 genome. No major deletions, insertions, or rearrangements were found. The highest homologies of the gag, pol, vpr, and vif reading frames to the corresponding clade B-Thai RL 42 sequences were 95.42%-97.08%. Phylogenetic trees showed the closest relationship of CNHN 24 and RL 42. CONCLUSION: The cloning and characterization of a virtually full-length HIV-1 B-Thai subtype in central China was completed in our laboratory. The data should be helpful to future studies on the genetic diversity of HIV-1.

Amino Acid Sequence↗

PubMed2004

[Effect of shenwu capsule on the peripheral blood lymphocyte DNA of rat model induced by beta-amyloid injection].

OBJECTIVE: To investigate the effect of the new Traditional Chinese Compound Shenwu Capsule on the damage of lymphocyte DNA and lipid peroxidation in peripheral blood of rats induced by beta-amyloid injection. METHOD: The animal model was made by injection of beta-amyloid25-35 into hippocampus of rats. DNA damage of lymphocytes was measured by the single cell gel electrophoresis (SCGE) combined with the laser scanning confocal microscopy (LSCM). The content of malondialdehyde (MDA) was determined by TBA assay. RESULT: Shenwu Capsule decreased the rate of the comet-like cell, comet-like cell lengh (TCL), and tail moment (TM) of lymphocytes in peripheral blood of model rats. Shenwu Capsule also declined the MDA content in serum of Abeta model rats. CONCLUSION: Shenwu Capsule has protective effect on peripheral blood lymphocyte DNA.

Amyloid beta-Peptides↗

PubMed2004

[Third order nonlinear optical properties of three kinds of metal phthalocyanines].

Using YAG laser, the nonlinear optical refractive indexes of three kinds of metal phthalocyanines in DMF, ZnPCS(C6H32N8S4Zn), AlPCS (C56H32AlClN8S4) and AlPCP (C6H32AlClN8O4) were studied with the method of Z-scan. Their third-order susceptibilities chi(3) were also calculated. The result shows that different central ion and different substituents could affect their third-order susceptibilities. The mechanisms of third order optical nonlinearity and energy transfer in the photodynamic therapy were discussed.

Coloring Agents↗

PubMed2004

[Measurement of borneol based on near infrared spectroscopy].

Infrared spectroscopy can provide integrated information of samples, and is easy to be applied to on-line control. So quality control specification of Chinese drugs can be improved by utilizing this method for the production of Chinese drugs. This method can accelerate the modernization process of Chinese drugs. Borneol is an effective constituent in lots of active Chinese drugs. The spectral characteristics of borneol in near infrared region were investigated in this paper. The characteristic absorption peaks of bomeol were found by measuring its spectra in near infrared band. There are five absorption peaks of borneol close to 4828, 5003, 5736, 7044 and 8387 cm(-1), respectively. Establishing a partial least square (PLS) model can get optimal results in model building experiment. The predictive results show that the linear relationship between twenty-five samples' predicted values and real values is good with regard to the content of borneol. In calibration model, the root mean square error of prediction (RMSEP) of the content of borneol is 0.28 mg x mL(-1) and the number of the principal components is equal to two. The experimental results show that infrared spectroscopy can be used as a means in the field of quality control of Chinese drugs and the measurement of effective constituents of Chinese drugs.

Calibration↗

PubMed2003

Genetic linkage analysis of longitudinal hypertension phenotypes using three summary measures.

BACKGROUND: Longitudinal data often have multiple (repeated) measures recorded along a time trajectory. For example, the two cohorts from the Framingham Heart Study (GAW13 Problem 1) contain 21 and 5 repeated measures for hypertension phenotypes as well as epidemiological risk factors, respectively. Direct modelling of a large number of serially and biologically correlated traits in the context of linkage analysis can be prohibitively complex. Alternatively, we may consider using univariate transformation for linkage analysis of longitudinal repeated measures. RESULTS: We evaluated the utility of three conventional summary measures (mean, slope, and principal components) for genetic linkage analysis of longitudinal phenotypes by analyzing the chromosome 10 data of the Framingham Heart Study. Except for the temporal slope, all of the summary methods and the multivariate analysis identified the previously reported region, marker GATA64A09, for systolic blood pressure or high blood pressure. Further analysis revealed that this region may harbor gene(s) affecting human blood pressure at multiple stages of life. CONCLUSION: We conclude that mean and principal components are feasible alternatives for genetic linkage analysis of longitudinal phenotypes, but the slope might have a separate genetic basis from that of the original longitudinal phenotypes.

Adult Children↗

PubMed2003

Multivariate sib-pair linkage analysis of longitudinal phenotypes by three step-wise analysis approaches.

BACKGROUND: Current statistical methods for sib-pair linkage analysis of complex diseases include linear models, generalized linear models, and novel data mining techniques. The purpose of this study was to further investigate the utility and properties of a novel pattern recognition technique (step-wise discriminant analysis) using the chromosome 10 linkage data from the Framingham Heart Study and by comparing it with step-wise logistic regression and linear regression. RESULTS: The three step-wise approaches were compared in terms of statistical significance and gene localization. Step-wise discriminant linkage analysis approach performed best; next was step-wise logistic regression; and step-wise linear regression was the least efficient because it ignored the categorical nature of disease phenotypes. Nevertheless, all three methods successfully identified the previously reported chromosomal region linked to human hypertension, marker GATA64A09. We also explored the possibility of using the discriminant analysis to detect gene x gene and gene x environment interactions. There was evidence to suggest the existence of gene x environment interactions between markers GATA64A09 or GATA115E01 and hypertension treatment and gene x gene interactions between markers GATA64A09 and GATA115E01. Finally, we answered the theoretical question "Is a trichotomous phenotype more efficient than a binary?" Unlike logistic regression, discriminant sib-pair linkage analysis might have more power to detect linkage to a binary phenotype than a trichotomous one. CONCLUSION: We confirmed our previous speculation that step-wise discriminant analysis is useful for genetic mapping of complex diseases. This analysis also supported the possibility of the pattern recognition technique for investigating gene x gene or gene x environment interactions.

Adult Children↗

PubMed2003

Baculoviral polyhedrin as a novel fusion partner for formation of inclusion body in Escherichia coli.

Baculoviral polyhedrin, which originated from Autographa californica nuclear polyhedrosis virus (AcNPV), was employed for the first time as a novel fusion partner for expression of foreign proteins in an Escherichia coli system. We characterized the expression of recombinant polyhedrin protein fused to green fluorescent protein (GFP). The polyhedrin fusion protein ( approximately 58 kDa) was successfully expressed as an insoluble inclusion body comprising approximately 30% of the total cellular protein. The E. coli expressing polyhedrin-GFP fusion protein showed higher cell growth ( approximately 1.8-fold) and higher GFP yield ( approximately 3.5-fold) than the strain expressing soluble single GFP. Interestingly, the polyhedrin fusion portion showed almost the same characteristics as the native baculoviral polyhedrin; it was rapidly solubilized under alkaline conditions, similar to the conditions found in the insect midgut. In addition, the polyhedrin fusion portion was rapidly digested by alkaline proteases in insect Plutella xylostella midgut as well as by alpha-chymotrypsin, a protease that has similar properties to insect midgut polyhedra-associated alkaline proteases. These unique properties suggest that baculoviral polyhedrin might be an advantageous fusion partner for production of foreign proteins, especially harmful proteins, in E. coli expression systems.

Baculoviridae↗

PubMed2003

Synthesis and SAR studies of potent HIV protease inhibitors containing novel dimethylphenoxyl acetates as P2 ligands.

Isopropyl substituted 4-thioazolyl valine side chains are highly optimized P(2)-P(3) ligands for C2 symmetry-based HIV protease inhibitors, as exemplified by the drug ritonavir. Replacement of the side chain with the conformationally constrained hexahydrofurofuranyloxy P(2) ligand in combination with a dimethylphenoxyacetate on the other end of the ritonavir core diamine yielded highly potent HIV protease inhibitors. The in vitro antiviral activity in MT4 cells increased by 10- and 20-fold, respectively, in the absence and presence of 50% human serum compared to ritonavir. The structure-activity relationships of inhibitor series with this combination of ligands were investigated. Preliminary pharmacokinetic studies in rats indicated rapid elimination of the inhibitors from the blood, and the plasma levels were not significantly enhanced by coadministration with ritonavir. However, the novel structural features and the high intrinsic antiviral potency of this series provides potential for the future exploration of prodrug strategies.

Animals↗

PubMed2003

Prevention of lipopolysaccharide-induced microangiopathy by gp49B1: evidence for an important role for gp49B1 expression on neutrophils.

gp49B1 is expressed on mast cells and inhibits immunoglobulin E-dependent activation and inflammation in vivo. We now show that gp49B1 is expressed on neutrophils and prevents neutrophil-dependent vascular injury in response to lipopolysaccharide (LPS). The intradermal (i.d.) injection of LPS into gp49B1-null (gp49B-/-) but not gp49B1-sufficient (gp49B+/+) mice elicited macroscopic hemorrhages by 24 h, which were preceded on microscopic analyses by significantly more intravascular thrombi (consisting of neutrophils, platelets, and fibrin) that occluded venules and by more tissue neutrophils than in gp49B+/+ mice. However, there were no differences in the number of intact (nondegranulating) mast cells or the tissue levels of mediators that promote neutrophil recruitment. Hemorrhage was prevented by depleting neutrophils, blocking beta2 integrin-intercellular adhesion molecule 1 interactions, or inhibiting coagulation. These characteristics indicate that gp49B-/- mice are exquisitely sensitive to a local Shwartzman reaction (LSR) after a single i.d. injection of LPS, whereas in the classic LSR, a second exposure is required for increased beta2 integrin function, intravascular neutrophil aggregation, formation of occlusive thrombi, and hemorrhage. Moreover, LPS increased gp49B1 expression on neutrophils in vivo. The results suggest that gp49B1 suppresses the LPS-induced increase in intravascular neutrophil adhesion, thereby providing critical innate protection against a pathologic response to a bacterial component.

Animals↗

PubMed2003

GBP binds kinesin light chain and translocates during cortical rotation in Xenopus eggs.

In Xenopus, axis development is initiated by dorsally elevated levels of cytoplasmic beta-catenin, an intracellular factor regulated by GSK3 kinase activity. Upon fertilization, factors that increase beta-catenin stability are translocated to the prospective dorsal side of the embryo in a microtubule-dependent process. However, neither the identity of these factors nor the mechanism of their movement is understood. Here, we show that the GSK3 inhibitory protein GBP/Frat binds kinesin light chain (KLC), a component of the microtubule motor kinesin. Upon egg activation, GBP-GFP and KLC-GFP form particles and exhibit directed translocation. KLC, through a previously uncharacterized conserved domain, binds a region of GBP that is required for GBP translocation and for GSK3 binding, and competes with GSK3 for GBP. We propose a model in which conventional kinesin transports a GBP-containing complex to the future dorsal side, where GBP dissociates and contributes to the local stabilization of beta-catenin by binding and inhibiting GSK3.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Directional sensing requires G beta gamma-mediated PAK1 and PIX alpha-dependent activation of Cdc42.

Efficient chemotaxis requires directional sensing and cell polarization. We describe a signaling mechanism involving G beta gamma, PAK-associated guanine nucleotide exchange factor (PIX alpha), Cdc42, and p21-activated kinase (PAK) 1. This pathway is utilized by chemoattractants to regulate directional sensing and directional migration of myeloid cells. Our results suggest that G beta gamma binds PAK1 and, via PAK-associated PIX alpha, activates Cdc42, which in turn activates PAK1. Thus, in this pathway, PAK1 is not only an effector for Cdc42, but it also functions as a scaffold protein required for Cdc42 activation. This G beta gamma-PAK1/PIX alpha/Cdc42 pathway is essential for the localization of F-actin formation to the leading edge, the exclusion of PTEN from the leading edge, directional sensing, and the persistent directional migration of chemotactic leukocytes. Although ligand-induced production of PIP(3) is not required for activation of this pathway, PIP(3) appears to localize the activation of Cdc42 by the pathway.

Actins↗

PubMed2003

Supramolecular assembly of poly(phenylene vinylene) with crown ether substituents to form nanoribbons.

Poly(para-phenylene vinylene) with crown ether substituents (C-PPV) could form nanoribbons through supramolecular assembly with K(+) in dilute chloroform solution. The length of the nanoribbons increased with an increase in the standing time of the C-PPV/K(+) solution. Experimental evidence to support the interaction between K(+) and crown ether substituents was provided, and the growth mechanism of C-PPV/K(+) nanorods to nanoribbons was proposed. The influence of the length of the nanoribbons on the photophysics of C-PPV was also investigated.

Journal Article↗