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Biomedical subjects

Yong Liu

Publications and source records attributed to Yong Liu.

At least 163 records · Page 9Linked to original sources
PubMed2004

[The anti-HBV effect and mechanism of C gene truncated mutant in vitro].

OBJECTIVE: To explore the effect and mechanism on HBV replication in C gene truncated mutant. METHODS: Protein expression of C gene truncated vector and wild C gene vector were assay by SDS-PAGE Western blot. Constructed C gene truncated expression vector was cotransfected with wild HBV genome; virus load was detected by PCR in the culture medium and the cell. The formation of core particle was assay by Native western blot. RESULTS: The recombinant vectors can efficiently express. Virus load of the cotransfected group by pcDNA3-deltaC and adwR9 was lower than that of control group in the culture medium and the cell. Protein band of the co-expressed group by pcDNA3-deltaC and pcDNA3-C showed slightly weaker than that of the co-expressed group by pcDNA3 and pcDNA3-C. CONCLUSION: C gene truncated mutant could interfere with the formation of core particle and reduce of HBV replication

Cell Line↗
PubMed2004

Comparison study on clinical and neuropathological characteristics of hamsters inoculated with scrapie strain 263K in different challenging pathways.

OBJECTIVE: To understand the infectious characteristics of a hamster-adapted scrapie strain 263K with five different routes of infection including intracerebral (i.c.), intraperitoneal (i.p.), intragastrical (i.g.), intracardiac and intramuscular (i.m.) approaches. METHODS: Hamsters were infected with crude- or fine-prepared brain extracts. The neuropathological changes, PrP(Sc) deposits, and patterns of PK-resistant PrP were analyzed by HE stain, immnunohistochemistry (IHC) assay and Western blot. Reactive gliosis and neuron loss were evaluated by glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE) specific IHC. RESULTS: The animals inoculated in i.m. and i.p. ways with crude PrP(Sc) extracts showed clinical signs at the average incubation of 69.2 +/- 2.8 and 65.5 +/- 3.9 days. Inoculation in i.c. and intracardiac ways with fine PrP(Sc) extracts (0.00035 g) caused similar, but relative long incubation of around 90 days. Only one out of eight hamsters challenged in i.g. way with low dosage (0.01 g) became ill after a much longer incubation (185 d), while all animals (4/4) with high dosage (0.04 g) developed clinical signs 105 days postinfection. The most remarkable spongiform degeneration and PrP(Sc) deposits were found in brain stem among the five challenge groups generally. The number of GFAP-positive astrocytes increased distinctly in brain stems in all infection groups, while the number of NSE-positive cells decreased significantly in cerebrum, except i.c. group. The patterns of PK-resistant PrP in brains were basically identical among the five infection routes. CONCLUSION: Typical TSE could be induced in hamsters by inoculating strain 263K in the five infection ways. The incubation periods in bioassays depend on infective dosage, administrating pathway and preparation of PrP(Sc). The neuropathological changes and PrP(Sc) deposits seem to be related with regions and inoculating pathways.

Administration, Oral↗
PubMed2004

Effects of TGF beta1 autocrine blockage on osteosarcoma cells.

OBJECTIVE: To evaluate the effects of transforming growth factor beta1 (TGFbeta1) autocrine blockage on proliferation activity and drug sensitivity of osteosarcoma. METHODS; Northern blot, MTT determination, and 3H thymidine incorporation were used to investigate the effects of antisense TGF beta1 gene on osteosarcoma. RESULTS: The proliferation of osteosarcoma cells transfected by antisense TGF beta1 gene was suppressed markedly, and adriamycin sensitivity was significantly increased. CONCLUSION: Blockage of osteosarcoma cells TGF beta1 autocrine loop inhibits cell proliferation and enhances chemotherapy sensitivity.

Antineoplastic Agents↗
PubMed2004

[The construction of attenuated Tiantan recombinant vaccinia virus vector with IFN-gamma receptor gene deletion].

OBJECTIVE: B8R gene encodes a secreted protein with homology to IFN-gamma receptor, which neutralizes the antiviral and immunological regulation activities of IFN-gamma. To improve the safety of vaccinia virus vector, an attenuated recombinant vaccinia virus with the B8R gene deletion from Tiantan vaccine strain (VTT) was constructed. METHODS: The transfer vectors were generated by joining B8R left flank, B8R right flank, vv promoter, LacZ, multicloning site and pBRSK fragments. The recombinant viruses VTTdeltaB8RLacZ (VTT with B8R deletion and LacZ insertion) were constructed by homologous recombination. RESULTS: The B8R deletion mutants were confirmed by dot blot with B8R gene probe and PCR amplification. The replication ability of VTTdeltaB8RLacZ strain in vitro was similar to that of the VTT. The skin lesions formed by VTTdeltaB8RLacZ (10(6) pfu) were significantly smaller and healed faster than those formed by VTT when injected intradermally to the rabbits,and no visible ulceration occurred. Meanwhile LacZ in VTKgpedeltaB8RLacZ was expressed stably. CONCLUSIONS: The attenuated vector with B8R gene deletion improves the safety of recombinant vaccinia virus vaccine B8R locus may be used as a new site for insertion of foreign genes in vaccinia virus vector.

Animals↗
PubMed2004

[Present situation and prospects of special fertilizer for traditional Chinese medicine herbs].

OBJECTIVE: To find out the present situation and the development trend special fertilizer of the traditional Chinese medicina plants. METHOD: By consulting a great deal of literatures on special fertilizer and fertilization on traditional Chinese medicine herbs, and based on the scientific research and manufacture experience of the author, and the theoretic actuality of the researches on the fertilization of traditional Chinese medicine herbs, the present study of the special fertilizer inside and outside of our country was analyzed. CONCLUSION: The view points of developing special fertilizer for Chinese traditional medicine were put forward, and the development trend of special fertilizer for traditional Chinese medicine herbs was forecasted.

Ecosystem↗
PubMed2004

[Transient expression and characterization of intracellular single chain Fv against the nucleocapsid protein of Hantavirus].

AIM: To transiently express an intracellular single chain Fv of monoclonal antibody 1A8 against nucleocapsid protein of Hantavirus and characterize the immunological activities of the expressed products. METHODS: COS-7 cells were transfected with mammalian expression vector 1A8-scFv-Ckappa/pCI-neo via lipofectin. The expressed product was identified by indirect immunofluorescence and immunoprecipitation. RESULTS: A diffuse pattern fluorescence was observed in less than 1% cytoplasm of transfected COS-7 cells. The binding of intracellular antibody fragments to NP antigen was confirmed by immunoprecipitation analysis. CONCLUSION: Transiently expressed single chain intrabodies can effectively target NP antigen in the cytoplasm. The present study may provide a new approach for treatment of Hantavirus.

Animals↗
PubMed2004

Quality of life in patients with liver cancer after operation: a 2-year follow-up study.

BACKGROUND: Quality of life (QL) is a concept which reflects the physical, social, and emotional attitudes and behaviours of an individual. QL assessment is becoming increasingly recognised as an outcome and predictor for cancer patients. Although hepatectomy has been widely accepted as treatment of choice to offer a chance of cure for patients with liver cancer, little is known about the subjective clinical results after this operation. This prospective study was designed to evaluate the Pre- and postoperative quality of life in patients with liver cancer. METHODS: The quality of life of 36 consecutive patients was measured using gastrointestinal quality of life index (GQLI) regularly 2 years after the operation, starting with a preoperative measurement. RESULTS: The score of mean preoperative GQLI was 106+/-13 points, and it was reduced significantly 2-10 weeks after the operation (86-98) (P<0.05-0.001). The quality of life recovered gradually. The GQLI score was 101+/-21 points 4 months after operation and increased to the preoperative level (P>0.05). In the patients who survived more than 9 months, the GQLI score was higher than that before the operation. Major hepatectomy (lobectomy and combined segmentectomy) reduced the GQLI score more evidently than did minor hepatectomy (simple segmentectomy) in 2-5 weeks after the operation (P<0.05). The age and preoperative liver function of the patients played an important role in the recovery of the quality of life in the early postoperative stage (P<0.05). The patients with tumor recurrence showed a continuous decrease of the quality of life (P<0.05-0.001). CONCLUSIONS: The assessment of the quality of life is meaningful for patients with liver cancer. Tumor recurrence, poor liver function and major operation are the most important factors for reducing the quality of life. Hepatic resection is justified by its effects on the survival and the quality of life of the patients.

Adult↗
PubMed2004

[Effects of ketamine-midazolam anesthesia on focal cerebral ischemic injury in rats].

OBJECTIVE: To compare the effects of anesthesia with ketamine and ketamine-midazolam on focal cerebral ischemic injury in rats and evaluate the neuroprotective effect of ketamine-midazolam anesthesia during surgical procedures. METHODS: Thirty male Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion (MCAO) under anesthesia with intraperitoneal administration of ketamine alone or in combination with midazolam (n=15). Neurological scoring was conducted the infarct size measured at 4 h and 24 h after the surgery. Histological examination was performed using TUNEL staining 72 h after MCAO. RESULTS: After MCAO, the neurological scores showed no significant difference between ketamine and ketamine-midazolam groups (1.57+/-0.65 vs 1.74+/-0.52, P>0.05), but the rats in the latter group had significantly smaller infarct size (38.48/+/-4.18/ vs 24.1/+/-4.63/, P<0.05) and lower apoptotic cell density (258+/-15 cells/mm2 vs 178+/-23 cells/mm2, P<0.05) in the penumbra. CONCLUSION: Compared with ketamine used alone, anesthesia with the combination of ketamine and midazolam may provide neuroprotection from ischemic cerebral injury by reducing the infarct size and lowering the cell apoptosis rate following MCAO in rats.

Adjuvants, Anesthesia↗
PubMed2004

[Renal tubular protection of shenqi fuzheng injection in treating primary nephrotic syndrome].

OBJECTIVE: To explore the effect and mechanism of Shenqi Fuzheng injection (SFI) on renal tubule in treating patients with primary nephrotic syndrome (PNS). METHODS: Eighty patients with PNS were randomly divided into two groups, 40 patients in the control group were treated by conventional therapy mainly with glucocorticoids; 40 patients in the treated group treated by conventional therapy plus intravenous injection of SFI additionally. The changes of serum albumin (sALB), urinary protein in 24 hrs (UP/24h), urinary levels of retinal binding protein (RBP), beta2 microglobulin (beta2-MG) and N-acetyl-D-glucosaminidase (NAG) as well as blood lipids before and after treatment were observed. RESULTS: After treatment, level of sALB increased and urinay levels of RBP, beta2-MG, NAG, UP/24h decreased in the treated group, as compared with those in the control group, showing significant difference (P < 0.05 or P < 0.01). Blood lipids level abated significantly after treatment in both groups (P < 0.01), comparison between them, levels of TC and LDL-C in the treated group were significantly lower than those in the control group (P < 0.01). CONCLUSION: SFI has protective effect on renal tubule in patients with PNS, also has effect on lowering blood lipids.

Adolescent↗
PubMed2004

[Gene expression of type X collagen in the intervertebral disc of idiopathic scoliosis patients].

OBJECTIVE: To observe the characteristics of gene expression of type X collagen in the cartilage of end-plate and the fibrous annulus in the intervertebral disc of idiopathic scoliosis (IS) patients. METHOD: Investigating the expression of type X collagen in the peak disc and the lower end disc of 21 IS patients, the peak disc of 16 congenital scoliosis (CS) and the lumbar disc of 3 normal people (according with the principle of medical ethnics) by reverse transcript polymerase chain reaction. RESULTS: The expression of type X collagen in the concave side of IS peak disc was higher than the convex side (P < 0.05). There was no significant difference of gene expression of type X collagen between the convex side and the concave side of the lower end disc (P > 0.05). The gene expression of type X collagen in the IS peak disc was higher than those of lower end disc (P < 0.05). For the CS peak discs, the expression of type X collagen of the concave side was higher than the convex side (P < 0.05). CONCLUSION: The expression of type X collagen of the IS peak disc increases, and the expression of type X collagen of the concave side is higher than the convex side. These changes may be secondary.

Adolescent↗
PubMed2004

[Comparison of pentobarbital and propofol on the outcome of focal cerebral ischemia model in rats].

OBJECTIVE: To compare the effects of pentobarbital and propofol on the outcome of focal cerebral ischemia model, and to evaluate the availability of propofol in setting the focal cerebral ischemia. METHODS: Thirty male Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) under pentobarbital or propofol intraperitoneal anesthesia (n=15 each). A modified Bederson's scoring system was adopted to assess neurological scoring at 4 h after the MCAO. TTC staining was used to determine the infarct size at 24 h after the MCAO. At day 3 after the MCAO, TUNEL and toluidine blue staining were performed to measure the density of apoptotic cells and surviving neurons in the penumbra. RESULTS: Neither neurological scoring (1.46 +/- 0.98 vs 1. 29 +/- 0.72), infarct size [(37.8 +/- 4.95)% vs (31.1 +/- 5.09)%] nor neuronal density in the penumbra [(740 +/- 24) neurons/mm2 vs (794 +/- 23) neurons/mm2] was statistically different between pentobarbital and propofol groups (P > 0.05). But apoptotic cell density in the penumbra was significantly higher in the propofol group than that in the pentobarbital group [(356 +/- 20) cells/mm2 vs (262 +/- 17) cells/mm2, P < 0.05]. CONCLUSION: In the establishment of the focal ischemia model in rats, anesthesia with propofol or pentobarbital induces similar neurological scoring, infarct size and survived neurons in the penumbra. Propofol anesthesia increases cell apoptosis in the penumbra compared with pentobarbital and its application might be an unsuitable anesthetic method in the model for evaluating the effect of procedures or drugs on cell apoptosis.

Adjuvants, Anesthesia↗
PubMed2004

Activation-induced cell death in T cells and autoimmunity.

Activation-induced cell death (AICD), which results from the interaction between Fas and Fas ligand, is responsible for maintaining tolerance to self-antigen. A defect in AICD may lead to development of autoimmunity. During the last several years, much progress has been made in understanding the mechanism(s) of AICD and its potential role in the pathogenesis of autoimmune diseases. In this review, we summarize the most recent progress on the regulation of the susceptibility of T cells to AICD and its possible involvement in autoimmune diseases.

Animals↗
PubMed2003

Estradiol represses prolactin-induced expression of Na+/taurocholate cotransporting polypeptide in liver cells through estrogen receptor-alpha and signal transducers and activators of transcription 5a.

Na(+)/taurocholate cotransporting polypeptide (ntcp) mediates the uptake of bile salts from plasma across the basolateral domain of the hepatocyte. We have demonstrated that ntcp expression can be induced by prolactin (PRL) and placental lactogen via the PRL receptor and signal transducers and activators of transcription (Stat)5a pathway. However, elevated levels of placental lactogen do not increase the expression of ntcp in pregnant rats. Because plasma estradiol (E(2)) levels are also elevated in pregnancy, we investigated the inhibitory effects of E(2) on PRL-induced ntcp activation. E(2) treatment inhibited the PRL-induced increase in liver ntcp mRNA to the same levels as in rats treated with E(2) alone. Estrogen receptor-alpha (ERalpha) mRNA and protein expression in liver were increased 2.6-fold and 2.2-fold, respectively, in pregnancy relative to controls. In HepG2 cells, E(2) repressed PRL-induced ntcp reporter gene expression in a dose-dependent manner in the presence of cotransfected ERalpha. The ERalpha antagonist ICI 182,780 reversed E(2)-induced repression, indicating specificity of inhibition by E(2). Overexpression of coactivator p300 did not reverse the inhibitory effects of E(2) and ERalpha. Western and gel shift analysis revealed that E(2)-bound ERalpha decreased the tyrosine phosphorylation and DNA-binding activity of Stat5a, indicating that the inhibitory effect of E(2) was mediated, at least in part, by interfering with PRL-mediated signal transduction. The present studies demonstrate the physiological significance of cross-talk between ERalpha and Stat5a in liver, in which both proteins are expressed. These data also establish a novel mechanism by which expression of ntcp, an important hepatic bile acid transporter, can be regulated by multiple hormones.

Animals↗
PubMed2003

Infection, replication, and cytopathology of human papillomavirus type 31 in trophoblasts.

Human papillomavirus (HPV) DNA is preferentially found in spontaneous abortions, specifically residing in trophoblasts, and transfected HPV-16 DNA replicates and produces progeny in 3A trophoblasts in culture. In this study 3A trophoblasts were shown to display both HPV receptors and infection by HPV-31b and HPV-6 virus resulted in de novo (increasing) HPV DNA replication in these cells (inhibited by neutralizing anti-HPV31b antibodies). Reverse transcription-polymerase chain reaction analysis revealed that E1;E4, E6, and L1 were significantly expressed at days 5 (early) and 10 (late), respectively, and in situ immunocytochemistry verified L1 protein expression. Perhaps most important, HPV 31b virus infection caused both a decrease in 3A trophoblast cell numbers in a dose-dependent manner and a low trophoblast-endometrial cell adhesion (both inhibited by neutralizing anti-HPV-31 antibodies). These data further support the hypothesis that HPVs are fully active in trophoblasts and may cause some spontaneous abortions.

Cell Adhesion↗
PubMed2003

Aligned nanotubes.

Since the discovery of carbon nanotubes by lijima in 1991, various carbon nanotubes with either a single- or multilayered graphene cylinder(s) have been produced, along with their noncarbon counterparts (for example, inorganic and polymer nanotubes). These nanostructured materials often possess size-dependent properties and show new phenomena related to the nanosize confinement of the charge carriers inside, which leads to the possibility of developing new materials with useful properties and advanced devices with desirable features for a wide range of applications. In particular, carbon nanotubes have been shown to exhibit superior properties attractive for various potential applications, ranging from their use as novel electron emitters in flat-panel displays to electrodes in electrochemical sensors. For many of the applications, it is highly desirable to have aligned/patterned forms of carbon nanotubes so that their structure/property can be easily assessed and so that they can be effectively incorporated into devices. In this Review, we present an overview on the development of aligned and micropatterned nanotubes, with an emphasis on carbon nanotubes.

Journal Article↗