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Biomedical subjects

Li Liu

Publications and source records attributed to Li Liu.

At least 127 records · Page 7Linked to original sources
PubMed2006

[Studies on germination characteristics of Platycodon grandiflorum seed].

OBJECTIVE: To find out the optimal condition for the germination by studying the effects of light, temperature, seed soaking and cultivation condition on Platycodon grandiflourm, and offer the basis for standardized culture of P. grandflorum. METHOD: The rate of water absorption of the seed was determined. The germination of P. grandiflorum seed was tested under following conditions: treatments under different temperature (10,15,20,25,30 degrees C), light treatments (light and dark), seed soaking time (12,24,36 h) and different germination cultivation conditions (on filter paper, between filter paper, between gauze,on gauze). RESULT: The water absorption of the seeds reached the maximal 120% within 36 h at 25 degrees C. The time of seeds soaking had limited effect on the germination of the seed, while temperature and light condition showed significant effects on the germination. CONCLUSION: The optimal condition for the germination of the seed of P. grandiflorum is as follow:seed soaking for 12 h, and 25 degrees C underlight.

Germination↗
PubMed2006

[Influence of exogenous substance on germination of Platycodon grandiflorum seeds].

OBJECTIVE: To study of exogenous substances on the germination rate of Platycodon grandiflorum and offer the basis for the standardized culture of P. grandiflorum. METHOD: At 25 degrees C, under darkness and lightness, do pretreatmeats on seeds by using GA3, H2O2, KMnO4, PEG at different concentrations. RESULT: The results indicated that the pretreatments with GA3 at a concentrating of 50-250 mg x L(-1) and 1%-2% of H2O2 could increase germination of P. grandiflorum seed at a certain degree. Contrariwise 0.1%-0.5% of KMnO4 and 15%-35% of PEG inhibited the germination. CONCLUSION: Pretreatment with 50-250 mg x L(-1)GA3 and H2O2 at a low cencontration could increase the seed germination of P. grandiflorum.

Dose-Response Relationship, Drug↗
PubMed2006

[Study on application of activated carbon in paclitaxel injection].

OBJECTIVE: To inspect the effect of activated carbon with different dosage and temperature on quality of paclitaxel injection. METHOD: Determinations in WS1-(X-026)-2001Z-paclitaxel injection were refered to compare the effect of different dosage and temperature for activated carbon on the taxol content, related material, clarity and bacterial endotoxin. RESULT: When used with 0.25% and 35 degrees C, activated carbon will ensure the quality of paclitaxel injection. CONCLUSION: 0.25% and 35 degrees C are the best condition when activated carbon is used in paclitaxel injection.

Antineoplastic Agents, Phytogenic↗
PubMed2006

[Effect of TCM syndrome-typing based therapy combined with cyclosporin in treating myelodysplastic syndrome].

OBJECTIVE: To observe the therapeutic effect of TCM syndrome-typing based therapy (TCM-STBT) combined with cyclosporin on myelodysplastic syndrome (MDS) and investigate the correlation of efficacy with TCM syndrome type and MDS type. METHODS: Fifty-eight MDS patients were classified into refractory anemia (RA) and RA with excess blast (RAEB) by FAB standard and randomly divided into the cyclosporin group (the treated group) and the alltransretinoic acid group (the control group), and both were subjected to STBT additionally. The therapeutic effect and changes of peripheral hemogram were observed and compared. RESULTS: The total effective rate and the total remission rate was 73% and 33% in the treated group, higher than that in the control group (39% and 0) respectively. Hemoglobin level, white blood cell and blood platelet count increased significantly in the treated group after treatment (P < 0.05), while only hemoglobin level rose obviously in the control group (P < 0.05). The total effective rate and markedly effective rate in patients with qi-blood deficiency syndrome type were higher than those with other syndrome types. CONCLUSION: TCM-STBT combined with cyclosporin has good efficacy in treating MDS and there is well correlation between the therapeutic efficacy and type of TCM syndrome or of MDS, indicating the STBT is necessory for TCM therapy.

Adult↗
PubMed2006

[Study on characteristics of seed germination of Salvia officinalis].

OBJECTIVE: To investigate the influences of lightness and temperature on seeds germination of Salvia officinalis, and offer the basis for the standardized cultivation of S. officinalis. METHOD: The morphological characters, 1 000-grains weight and rate of water absorption of the seed were observed, the germination capacity, percent of germination power and germination index at the five different degrees: 10, 15, 20, 25, 30 degrees C were also measared. RESULT: 1 000-grains weight of the seeds was 8.03 g, the rate of water absorption is 49% within 24 h, the highest rate of germination capacity reached 85.33%, the germination index is 45.56. CONCLUSION: The lightness and 25 degrees C are the most suitable parameters for the seed germination of S. officinalis.

Germination↗
PubMed2005

[Sensory gating of patients with first-episode schizophrenia].

OBJECTIVE: To investigate the characteristics of sensory gating P50 of patients with first-episode schizophrenia. METHODS: The auditory evoked potentials P50 were recorded in 66 patients (Group Sch) with first-episode schizophrenia and 92 normal controls (Group NC) by using conditioning/testing paradigm presented with auditory double click stimuli. RESULTS: The value of S1-P50 of Group Sch was 3 microV +/- 2 microV, significantly lower than that of Group NC (6 microV +/- 3 microV, P <0.01). The value of S2-P50 of Group Sch was 4 microV +/- 2 microV, significantly higher than that of Group NC (2 microV +/- 1 microV, P < 0.01). The S2/S1 ratio of Group Sc was 81% +/- 40%, significantly higher than that of Group NC (42% +/- 21%, P < 0.01). The value of S2 - S1 of Group Sch was 2 microV +/- 1 mciroV, significantly lower than that of Group Sch (3 mciroV +/- 2 microV). The value of 100 (1-S2/S1) of Group Sch was 19% +/- 17%, significantly lower than that of Group NC (58% +/- 21% , P < 0.01). CONCLUSION: Sensory gating deficit exists in the patients with first-episode schizophrenia, manifested in deficiency of inhibition that can be quantitatively observed by measuring auditory evoked potential P50.

Adolescent↗
PubMed2005

Identification and expression analysis of alternatively spliced isoforms of human interleukin-23 receptor gene in normal lymphoid cells and selected tumor cells.

Interleukin 23 (IL-23) is a new member of the IL-12 family that plays a critical role in promoting the proliferation of memory T helper 1 cells. The heterodimerized IL-23 receptor is composed of a shared IL-12 receptor beta 1 (IL-12Rbeta1) and an IL-12Rbeta2-related molecule called IL-23R. The standard form of IL-23R is encoded by at least 12 exons. Here, we demonstrate that at least six spliced isoforms of IL-23R (IL-23R1 to 6) can be generated through alternative splicing. The splicing strategies for the IL-23R gene are complicated and most often result in the deletion of exon 7 and/or exon 10. Translation prediction revealed that these spliced variants result in either premature termination to give rise to a diverse form of receptor ectodomain, or a frameshift to generate various lengths of the IL-23R endodomain. Differential expressions of IL-23R spliced variants are observed in natural killer and CD3+ CD4+ T cells. The expressions of these spliced variants are also prevalently and complicatedly regulated in tumor cell lines. Interestingly, only IL-23R2 and/or IL-23R4 variants are predominantly detected in certain human lung carcinomas, but not in their resected normal margin tissues. Thus, our results indicate that the regulation of alternative splicing on the IL-23R gene is complicated, and the preferential expression of certain IL-23R spliced variants may be a contributive factor to the pathogenesis of certain cancers.

Alternative Splicing↗
PubMed2005

Point mutation at single tyrosine residue of novel oncogene NOK abrogates tumorigenesis in nude mice.

Receptor protein-tyrosine kinases (RPTKs) are tightly regulated during normal cellular processes including cell growth, differentiation, and metabolism. Recently, a RPTK-like molecule named novel oncogene with kinase-domain (NOK) has been cloned and characterized. Overexpression of NOK caused severe cellular transformation as well as tumorigenesis and metastasis in nude mice. In the current study, we generated two tyrosine-->phenylalanine (Y-->F) point mutations (Y327F and Y356F) within the endodomain of NOK that are well conserved in many RPTK subfamilies and are the potential tyrosine phosphorylation sites important for major intracellular signaling. Using BaF3 cells stably expressing the ectodomain of mouse erythropoietin receptor, and the transmembrane and endodomain of NOK (BaF3-E/N), we were able to show that point mutations at either Y327 or Y356 dramatically blocked cellular transformation by NOK as examined by colony formation and cellular DNA synthesis. In addition, tumorigenesis induced by BaF3-E/N was completely abrogated upon the introduction of either single mutation. Importantly, signaling studies revealed that the activation of extracellular signal-regulated kinase was inhibited by Y356F and was significantly reduced by Y327F. Both mutations significantly impaired Akt phosphorylation. Interestingly, both mutations did not affect the kinase activity of NOK. Moreover, apoptotic analysis revealed that both mutations accelerated cell death by activating caspase-3-mediated pathways. Thus, our study shows that these potential tyrosine phosphorylation sites may play critical roles in NOK-mediated tumorigenesis both in vitro and in vivo.

Animals↗
PubMed2005

Identification and functional characterization of a novel interleukin 17 receptor: a possible mitogenic activation through ras/mitogen-activated protein kinase signaling pathway.

Interleukin-17 receptor (IL-17R) is increasingly emerged as a distinct receptor family functioning in diverse cellular processes including inflammation and cancer. In this study, we uncovered a novel member of IL-17R from mouse tissue that was named mouse IL-17RE (mIL-17R). Mouse IL-17RE cDNA is composed of at least 14 exons and presents at least 6 spliced isoforms (mIL-17RE1-6) with a molecular weight ranging from 34.2 to 70.1 kD. Mouse IL-17RE is expressed in limited tissues such as lung, kidney, stomach, intestine and testis, etc., and is mainly localized in the cytoplasm and on cell membrane. IL-17RE can also be detected in numerous tumor cell lines. Importantly, a mitogenic effect was detected in BaF3 cells stably transfected with the chimeric receptor fused by the ectodomain of erythropoietin receptor (EPOR) with the transmembrane and endomain of IL-17RE in a serum-dependent but EPO-independent manner. Moreover, ERK1/2 phosphorylation was significantly up-regulated as the dose of mIL-17RE increased. Specific RNAi targeting at mIL-17RE dramatically inhibited the activation of ERK1/2, indicating that mIL-17RE could functionally activate RAS/MAPK signaling pathway. Using dominant negative MEK (Dn-MEK) or RAS (Dn-RAS) as a signaling blocker, we were able to show that mIL-17RE probably activated RAS/MAPK signaling at or upstream of RAS. Overall, our results strongly indicate that mIL-17RE may belong to a novel growth-receptor like molecule that has the capability to support cellular mitogenesis through RAS/MAPK pathway.

Alternative Splicing↗
PubMed2005

Novel action of indoleamine 2,3-dioxygenase attenuating acute lung allograft injury.

RATIONALE: Lung allografts are prone to reperfusion injury and acute rejection, which, in addition to infiltrating lymphocytes, are accompanied by neutrophil infiltration and neutrophil-associated oxidative stress. Indoleamine 2,3-dioxygenase (IDO) is a unique cytosolic enzyme that possesses T-cell-suppressive and antioxidant properties. OBJECTIVES: The purpose of this study was to determine if genetic up-regulation of IDO could ameliorate acute lung allograft injury. METHODS: Lung orthotopic transplants were performed using Lewis donors and Sprague-Dawley rat recipients (allografts) or the same strain (isografts). Plasmid-encoding human IDO was delivered to donor lungs in vivo using a nonviral gene-transfer vector, polyethylenimine. Transplanted lungs were evaluated at 6 d post-transplantation based on pulmonary function, histology, inflammatory responses, and their associated oxidative stress. Basic biology of the IDO-overexpressing lung cells was evaluated in vitro in response to external oxidant. MEASUREMENTS AND MAIN RESULTS: This gene delivery method led to uniform transgene expression in lung tissue distributed in airway, alveolar epithelial, and endothelial cells. IDO overexpression in lung allografts resulted in a significant protective effect with improvement in functional properties (peak airway pressure and oxygenation) and histologic appearance. Although IDO was able to block local T-cell responses, it failed to abrogate neutrophilic infiltration and the inflammation-associated oxidative stress. IDO-enhanced lung cells were resistance to oxidant-induced necrosis and apoptosis by limiting intracellular reactive oxygen species formation. CONCLUSIONS: These results demonstrate that IDO prevents acute lung allograft injury through augmenting the local antioxidant defense system and inhibiting alloreactive T-cell responses.

Acute Disease↗
PubMed2005

Role of plasma membrane Ca2+-ATPase in contraction-relaxation processes of the bladder: evidence from PMCA gene-ablated mice.

We investigated the roles and relationships of plasma membrane Ca(2+)-ATPase (PMCA), sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA)2, and Na(+)/Ca(2+) exchanger (NCX) in bladder smooth muscle contractility in Pmca-ablated mice: Pmca4-null mutant (Pmca4(-/-)) and heterozygous Pmca1 and homozygous Pmca4 double gene-targeted (Pmca1(+/-)Pmca4(-/-)) mice. Gene manipulation did not alter the amounts of PMCA1, SERCA2, and NCX. To study the role of each Ca(2+) transport system, contraction of circular ring preparations was elicited with KCl (80 mM) plus atropine, and then the muscle was relaxed with Ca(2+)-free physiological salt solution containing EGTA. We measured the contributions of Ca(2+) clearance components by inhibiting SERCA2 (with 10 microM cyclopiazonic acid) and/or NCX (by replacing NaCl with N-methyl-D-glucamine/HCl plus 10 microM KB-R7943). Contraction half-time (time to 50% of maximum tension) was prolonged in the gene-targeted muscles but marginally shortened when SERCA2 or NCX was inhibited. The inhibition of NCX significantly inhibited this prolongation, suggesting that NCX activity might be augmented to compensate for PMCA4 function in the gene-targeted muscles under nonstimulated conditions. Inhibition of SERCA2 and NCX as well as gene targeting all prolonged the relaxation half-time. The contribution of PMCA to relaxation was calculated to be approximately 25-30%, with that of SERCA2 being 20% and that of NCX being 70%. PMCA and SERCA2 appeared to function additively, but the function of NCX might overlap with those of other components. In summary, gene manipulation of PMCA indicates that PMCA, in addition to SERCA2 and NCX, plays a significant role in both excitation-contraction coupling and the Ca(2+) extrusion-relaxation relationship, i.e., Ca(2+) homeostasis, of bladder smooth muscle.

Animals↗
PubMed2005

Phosphorylation of IkappaB-beta is necessary for neuronal survival.

Cerebellar granule neurons undergo apoptosis when switched from culture medium containing depolarizing levels of potassium (high potassium or HK) to nondepolarizing medium (low potassium or LK). We showed that in healthy neurons maintained in HK medium, IkappaB-beta is phosphorylated at a novel site, Tyr-161. LK-induced neuronal apoptosis is accompanied by a decrease in the extent of IkappaB-beta phosphorylation at this residue. Tyr-161 shares similarity to the consensus sequence for phosphorylation by the nonreceptor tyrosine kinases Abl and Arg. Arg phosphorylates Tyr-161 differentially in vitro, and LK treatment does cause a down-regulation of Arg activity. Moreover, treatment of neurons with two structurally distinct and highly selective Abl inhibitors, PD173955 and Gleevec, blocks HK-induced phosphorylation of IkappaB-beta at Tyr-161 and induces neuronal apoptosis. Overexpression of wild-type IkappaB-beta blocks LK-induced apoptosis, but this effect is abolished when Arg is pharmacologically inhibited. On the other hand, forced overexpression of IkappaB-beta in which Tyr-161 is mutated inhibits survival in HK demonstrating the importance of this residue to neuronal survival. Phosphorylation of IkappaB-beta enhances its association with p65/RelA causing an increase in NF-kappaB DNA binding activity. Our results identified IkappaB-beta phosphorylation as a key event in neuronal survival and provided a mechanism by which this is mediated.

Animals↗
PubMed2005

Functional GPCR microarrays.

This paper describes G-protein-coupled receptor (GPCR) microarrays on porous glass substrates and functional assays based on the binding of a europium-labeled GTP analogue. The porous glass slides were made by casting a glass frit on impermeable glass slides and then coating with gamma-aminopropyl silane (GAPS). The emitted fluorescence was captured on an imager with a time-gated intensified CCD detector. Microarrays of the neurotensin receptor 1, the cholinergic receptor muscarinic 2, the opioid receptor mu, and the cannabinoid receptor 1 were fabricated by pin printing. The selective agonism of each of the receptors was observed. The screening of potential antagonists was demonstrated using a cocktail of agonists. The amount of activation observed was sufficient to permit determinations of EC50 and IC50. Such microarrays could potentially streamline drug discovery by helping integrate primary screening with selectivity and safety screening without compromising the essential functional information obtainable from cellular assays.

Drug Evaluation, Preclinical↗
PubMed2005

Improved solvent-free microwave extraction of essential oil from dried Cuminum cyminum L. and Zanthoxylum bungeanum Maxim.

Solvent-free microwave extraction (SFME) is a recently developed green technique which is performed in atmospheric conditions without adding any solvent or water. SFME has already been applied to extraction of essential oil from fresh plant materials or dried materials prior moistened. The essential oil is evaporated by the in situ water in the plant materials. In this paper, it was observed that an improved SFME, in which a kind of microwave absorption solid medium, such as carbonyl iron powders (CIP), was added and mixed with the sample, can be applied to extraction of essential oil from the dried plant materials without any pretreatment. Because the microwave absorption capacity of CIP is much better than that of water, the extraction time while using the improved SFME is no more than 30 min using a microwave power of 85 W. Compared to the conventional SFME, the advantages of improved SFME were to speed up the extraction rate and need no pretreatment. Improved SFME has been compared with conventional SFME, microwave-assisted hydrodistillation (MAHD) and conventional hydrodistillation (HD) for the extraction of essential oil from dried Cuminum cyminum L. and Zanthoxylum bungeanum Maxim. By using GC-MS system the compositions of essential oil extracted by applying four kinds of extraction methods were identified. There was no obvious difference in the quality of essential oils obtained by the four kinds of extraction methods.

Chromatography, Liquid↗
PubMed2005

Novel triazole based inhibitors of Ras farnesyl transferase.

A novel series of potent inhibitors of Ras farnesyl transferase possessing a 1,2,4-triazole pharmacophore is described. These inhibitors were discovered from a parallel synthesis effort and were subsequently optimized to in vitro IC(50) value of less than 1nM.

Amino Acid Sequence↗
PubMed2005

Analysis of spliceosomal complexes in Trypanosoma brucei and silencing of two splicing factors Prp31 and Prp43.

In trypanosomatids all mRNAs undergo trans-splicing, whereas cis-splicing is restricted to a few transcripts. Trans-splicing is mechanistically similar to cis-splicing, however, little is known about the trans-splicing machinery and its underlying mechanism. In this study, we examined the involvement of splicing factors in cis- and trans-splicing by RNA interference (RNAi). Two factors (Prp31 and Prp43) were found to be essential for both pathways, suggesting that splicing factors are shared by these two reactions. We identified a 45S complex carrying pre-mRNA and all the U-snRNAs, including U1 and the SL RNA, suggesting that a single spliceosomal complex may potentially conduct both trans- and cis-splicing.

Animals↗
PubMed2005

Synthesis and evaluation of novel enhanced gene reporter molecules: detection of beta-galactosidase activity using 19F NMR of trifluoromethylated aryl beta-D-galactopyranosides.

Gene therapy has emerged as a promising strategy for treatment of various diseases, but there is a pressing need for the development of non-invasive reporter techniques based on appropriate molecules and imaging modalities to assay gene expression. We now report the design, synthesis, and evaluation of novel enhanced reporter molecules, which reveal lacZ gene expression: trifluoromethylated aryl beta-D-galactopyranosides. A series of five molecular structures were screened in solution and with stably transfected lacZ expressing human MCF7 breast cancer cells in vitro. p-Trifluoromethyl-o-nitrophenyl beta-D-galactopyranoside (PCF(3)ONPG) was found to exhibit valuable properties including a single (19)F NMR signal, stability in aqueous solution and with wild type cells, but a chemical shift response to enzyme cleavage (Deltadelta=1.14 ppm) in breast cancer cells transfected to stably express lacZ.

Fluorine↗