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Biomedical subjects

Chao Liu

Publications and source records attributed to Chao Liu.

At least 91 records · Page 5Linked to original sources
PubMed2005

[Receptor-related mechanism of proliferation inhibilion and apoptosis induetion of human tongue squamous cell line Tca8113 by retinoids].

OBJECTIVE: To investigate the receptor-related mechanism of retinoids inhibiting proliferation and inducing apoptosis of human oral squamous cell carcinoma cell line Tca8113. METHODS: The effects of 3 retinoids (namely 9-cis-RA, at-RA and 13-cis-RA), TTNPB (RAR agonist) and methoprene acid (Ma, RXR agonist) on proliferation and cell cycle of Tca8113 cells were analyzed by MTT assay and flow cytometry. The roles of these agents in inducing apoptosis of Tca8113 cells were also evaluated by detecting the expression of Bcl-2/Bax, TUNEL and active caspase-3 analysis. RESULTS: Both retinoids and TTNPB could inhibit the proliferation of Tca8113 cells, and the effect of TTNPB was the most powerful in all the reagents, but MA had no such effect. At the concentration of 1 x 10(-5) mol/L, all the agents except for Ma could increase the percentage of G(1)/G(0)-stage cells after incubation of the cells for 24 h and 48 h. Retinoids and TTNPB could up-regulate the expression of Bax and down-regulate Bcl-2 expression. The results of TUNEL demonstrated that retinoids and TTNPB, but not Ma, could induce apoptosis of Tca8113 cells as compared with the control group (P<0.05). Except for Ma, all the agents up-regulated caspase-3 expression, and the effect of TTNPB was the strongest (P<0.05). CONCLUSIONS: Retinoids can suppress the proliferation of and induce apoptosis of Tca8113 cells, the effect of which involves activation of RAR but not RXR. caspase-3 pathway is involved in apoptosis-inducing effects of retinoids.

Antineoplastic Agents↗
PubMed2005

Effects of single herbal drugs on adhesion and migration of melanocytes.

OBJECTIVE: To find herbs with effects on adhesion and migration of melanocytes in vitro. MATERIALS AND METHODS: Ethanol extracts from 14 herbs were tested. Normal human melanocytes were obtained from neonatal foreskin, and the 48-well culture dish covered with fibronectin was used for the melanocyte adhesion assay. Motility was assessed by using the micropore filter method. RESULTS: The extracts of Danshen (Radix Salviae Miltiorrhizae), Tusizi (Semen Cuscutae) and Honghua (Flos Carthami) could enhance melanocyte adhesion to fibronectin, while Cijili (Fructus Tribuli) and Huangqi (Radix Astragali) promote melanocyte migration in vitro. Buguzhi (Fructus Psoraleae), Nü Zhen Zi (Fructus Ligustri Lucidi) and Baizhi (Radix Angelicae Dahuricae) could promote both adhesion and migration of melanocytes. CONCLUSION: The above herbs may play a role through promoting adhesion and/or migration of melanocytes in the treatment of vitiligo.

Cell Adhesion↗
PubMed2005

[Determination of catechin and its analogues in Spatholobus suberectus by RP-HPLC].

OBJECTIVE: To develop a method for determination of catechin and its analogues in Spatholobus suberectus. METHOD: Gallocatechin, catechin and epicatechin are used as reference substances. Chromatographic assay is performed on a C18 colum. The mobile phase is composed of methanol and acetic acid solution with gradient elution. Velocity of flow is 0.8 mL x min(-1) and the detection wavelength is 270 nm. RESULT: The calibration curves of gallocatechin, catechin and epicatechin are linear within the range of 0.397 microg to 1.986 microg, 0.404 microg to 2.019 microg and 0.405 microg to 2.024 microg. The recoveries of them are 97.2%, 100.8% and 98.8%, and the RSD are 1.7%, 2.4%, 2.4% (n = 5). CONCLUSION: The method is simple, rapid and suitable for the determination of catechin and its analogues in S. suberectus.

Catechin↗
PubMed2004

Possible stem cell origin of human cholangiocarcinoma.

AIM: To investigate the expression of CD34 and c-kit (receptor of stem cell factor) in cholangiocarcinoma. METHODS: Fifteen cases of intrahepatic cholangiocarcinoma and 17 cases of extrahepatic cholangiocarcinoma were studied in this experiment. Using Envision detection system, paraffin-embedded sections of the resected cholangiocarcinoma tissue were stained with antibodies against CD34 and c-kit, respectively. The sections were counterstained with hematoxylin, and the results were examined under light microscope. Normal tonsil and mammary tissues were used as positive controls for CD34 and c-kit, respectively. RESULTS: CD34 was positive in all sections, but only in capillary endothelial cells of tumor tissue. No cholangiocarcinoma cells were positive for CD34. In one case of extrahepatic cholangiocarcinoma, a few tumor cells (about 5%) were immunoreactive with c-kit. CONCLUSION: CD34 or c-kit positive cells in liver tissue may represent liver stem cells, as they can differentiate into mature biliary cells in vitro. The expression of c-kit by some cholangiocarcinoma cells suggests that cholangiocarcinoma might originate from liver stem cells. However, other mechanisms of hepatocarcinogenesis, such as de-differentiation of mature cholangiocytes, may also exist.

Adult↗
PubMed2004

[The effective analysis on clearance of pararectal lymph nodes for carcinoma of rectum].

OBJECTIVE: To consider the relationship to survival rate and quality of life with pararectal lymphadenectomy for lower carcinoma of rectum. METHODS: The radical operation was performed on 780 cases of progressive cancer located at peritoneal reflection or below it, Among them, 352 cases only cleared in abdominal cavity, 428 cases coupled with extra-peritoneal histopathological type. RESULTS: Urinary function injured, the group cleared in abdominal cavity was 12 cases, accounted for 3.6%; the group coupled with extra-peritoneal clearance was 225 cases, for 52.5% (P < 0.01). Sexual function damaged (only for male), the abdominal cavity group was 23 cases, for 12.6% (23/185); the coupled group was 127 cases, for 53.4% (127/238), (P < 0.01). Local relapse rate, the abdominal cavity group was 15.8% (56/352); the coupled group was 8.6% (41/428), (P < 0.05). 5-year survival rate, the abdominal cavity group was 52.2%; the coupled group was 58.5% (P < 0.05). CONCLUSION: By contrast, although abdominal cavity coupled with extraperitoneal lymphadenectomy acted to cut down local relapse and to elevate 5-year survival rate, the postoperative quality of life appeared to be seriously affected.

Female↗
PubMed2004

Down-regulation of protein kinase Ceta by antisense oligonucleotides sensitises A549 lung cancer cells to vincristine and paclitaxel.

Previous studies point to protein kinase C (PKC) isozyme eta as a resistance factor in cancer cells. Therefore, we investigated whether down-regulation of PKCeta with second generation antisense oligonucleotides (ODNs) would sensitise A549 human lung carcinoma cells to cytostatics. The effects were compared to the outcome of Bcl-xL down-regulation. Upon treatment with antisense ODNs, PKCeta and Bcl-xL were both significantly reduced on mRNA and protein level. Down-regulation of either PKCeta or Bcl-xL in combination with vincristine or paclitaxel resulted in a significant increase in caspase-3 activity compared to that in the control oligonucleotide treated cells. In addition, PKCeta down-regulation augmented vincristine-induced dissipation of mitochondrial transmembrane potential. In conclusion, these results confirm that PKCeta might represent a considerable resistance factor and an interesting target to improve anticancer chemotherapy.

Antineoplastic Agents, Phytogenic↗
PubMed2004

Study on the relationship between heat shock protein 70 and toll-like receptor-4 of monocytes.

To explore the relation between human heat shock protein 70 (hsp70) and TLR4 in human monocytes in vitro, human monocytes were stimulated with various concentrations of HSP70, and TNF-alpha production in supernatants was measured by ELISA. Pre-incubated with or without anti-TLR4 mAb, and stimulated with hsp70 (5.0 microg/ml), NF-kappaB p65 of human monocytes in different time points were detected by immunohistochemistry and monocyte surface expression of TLR4 was measured by flow cytometry. After the human monocytes were pre-incubated with various concentrations of anti-TLR4 and stimulated with hsp70 (5.0 microg/ml), TNF-alpha production in supernatants was measured. The results showed that hsp70 enhanced NF-kappaB activation, which was clearly inhibited by anti-TLR4, with the positive cell ratios being 67.44%, 39.17%, 31.56% and 28.05 %, respectively. TLR4 was rapidly down-regulated in the presence of hsp70. MFI of TLR4 on monocytes in different time points were 87.77 +/- 5.38, 78.16 +/- 6.01 and 45.17 +/- 4.97 (P<0.05), 26.98 +/- 5.83 (P<0.01), respectively. Moreover, hsp70-induced TNF-alpha production by human monocytes was inhibited by anti-TLR4. It is suggested that TLR4 is involved in the hsp70-mediated activation of innate immunity.

HSP70 Heat-Shock Proteins↗
PubMed2004

Presence of markers for liver progenitor cells in human-derived intrahepatic biliary epithelial cells.

AIMS: Rodent intrahepatic bile duct may harbor bipotential liver progenitor cells. In this study, human-derived intrahepatic biliary epithelial cells (BECs) were investigated in terms of whether they have the character of liver progenitor cells. METHODS: Ten liver tissue specimens were obtained after partial hepatectomy or liver explantation. Intrahepatic BECs were isolated by density-gradient centrifugation and immunomagnetic separation using anti-human epithelial antigen and cultured in medium containing epidermal growth factor and hepatocyte growth factor. The isolated and cultured cells were characterized by immunostaining and reverse transcription polymerase chain reaction with a variety of markers for fetal hepatocytes and liver progenitor cells. RESULTS: These cells had proliferated for up to 18 weeks in vitro. They continuously expressed epithelial markers (cytokeratin (CK) 8 and CK 18) as well as biliary markers (CK 7 and CK 19). Remarkably, some isolated and cultured cells also expressed markers for fetal hepatocytes and liver progenitor cells, including albumin, alpha-fetoprotein, alpha1-antitrypsin, c-kit and chromogranin-A. CONCLUSION: Some human-derived intrahepatic BECs coexpressed markers for liver progenitor cells. This finding further supports the hypothesis that the human biliary tree may also consist of liver progenitor cells.

Adult↗
PubMed2004

Expression and purification of immunologically reactive DPPD, a recombinant Mycobacterium tuberculosis skin test antigen, using Mycobacterium smegmatis and Escherichia coli host cells.

DPPD is a Mycobacterium tuberculosis recombinant antigen that elicits specific delayed type hypersensitivity reactions similar in size and morphological aspects to that elicited by purified protein derivative, in both guinea pigs and humans infected with M. tuberculosis. In addition, earlier clinical studies with DPPD suggested that this molecule could improve the specificity of the tuberculin skin test, which is used as an important aid for the diagnosis of tuberculosis. However, these studies could only be performed with DPPD engineered as a fusion molecule with another Mycobacterium spp. protein because no expression of DPPD could be achieved as a single molecule or as a conventional fusion protein in any commercial system. Although recombinant fusion proteins are in general suitable for several biological studies, they are by definition not ideal for studies involving highly purified and defined polypeptide sequences. Here, we report two alternative approaches for the expression of immunologically reactive recombinant genuine DPPD. The first approach used the rapidly growing, nonpathogenic Mycobacterium smegmatis as host cells transformed with the pSMT3 plasmid vector containing the full-length DPPD gene. The second approach used Escherichia coli transformed with the pET-17b plasmid vector containing the DPPD gene engineered in a three-copy fusion manner in tandem with itself. Though at low levels, expression and purification of immunologically reactive DPPD in M. smegmatis could be achieved. More abundant expression and purification of DPPD as a homo-trimer molecule was achieved in E. coli (> or =2 mg/L of bacterial broth cultures). Interestingly, expression could only be achieved in host cells transformed with the DPPD gene containing its leader peptide. However, the expressed proteins lacked the leader sequence, which indicates that processing of the M. tuberculosis DPPD gene was accurately achieved and necessary in both M. smegmatis and E. coli. More importantly, the delayed type hypersensitivity reactions elicited by purified molecules in guinea pigs infected with M. tuberculosis were indistinguishable from that elicited by purified protein derivative. Because the DPPD gene is present only in the tuberculosis-complex organisms of the Mycobacterium genus, these highly purified molecules should be helpful in identifying individuals sensitized with tubercle bacilli.

Animals↗
PubMed2004

[Detection of RNA of SARS coronavirus in hospital sewage].

OBJECTIVE: In order to explore the existence of SARS coronavirus (Co-V) and/or its RNA in sewage of hospitals administered SARS patients. METHODS: A novel electropositive filter was used to concentrate the SARS-CoV from the sewage of two hospitals administered SARS patients in Beijing, including twelve 2,500 ml sewage samples from the hospitals before disinfection, and ten 25,000 ml samples after disinfection; as well as cell culture, RT-PCR and sequencing of gene to detect and identify the viruses from sewage. RESULTS: There was no live SARS-CoV detected in the sewage in this study. The nucleic acid of SARS-CoV had been found in the 12 sewage samples before disinfection from both hospitals by semi-nested PCR. After disinfection, SARS-CoV RNA could only be detected from the samples from the 309th Hospital, and the others were negative. CONCLUSION: It provides evidence that there is no live SARS-Cov in the sewage from hospitals with SARS patients though SARS-CoV RNA can be detected.

Hospitals↗
PubMed2004

[Advance of chemistry and bioactivities of catechin and its analogues].

Catechin and its analogues are varied and distributed widely. They have significant bioactivity on clearing free radical, anti-cancer, anti-flammatory, anti-allergic, anti-mutation, anti-aging, improving liver function, and so on. Recently, catechins (GTC) in green tea have given rise to comprehensive attention all over the world, and will have a wonderful prospect. The progress in studies of the structures, spectrum characters, resources and bioactivities of catechin and its analogues has been reviewed.

Animals↗
PubMed2003

Extended left hepatectomy--modified operation planning based on three-dimensional visualization of liver anatomy.

BACKGROUND: Based on the patient history of a 62-year-old man with a centrally located hepatocellular carcinoma we describe the potential influence of three-dimensional computed tomography (3D CT) on operation planning in extended left hepatectomy. METHOD AND RESULTS: By 3D reconstruction of the liver, not only variations of the intrahepatic vascular structure but also the number and extent of portal venous segments, as well as their relation to hepatic veins, can be visualized. Thus, areas at risk for either devascularization or venous congestion may be identified prior to liver resection. This is particularly important in extended hepatectomies with a small liver remnant, where already minor complications may have fatal consequences. CONCLUSION: In these resections, operation planning may be improved substantially by pre-operative 3D reconstruction.

Carcinoma, Hepatocellular↗
PubMed2003

A comparison of truncated total least squares with Tikhonov regularization in imaging by ultrasound inverse scattering.

For good image quality using ultrasound inverse scattering, one alternately solves the well-posed forward scattering equation for an estimated total field and the ill-posed inverse scattering equation for the desired object property function. In estimating the total field, error or noise contaminates the coefficients of both matrix and data of the inverse scattering equation. Previous work on ill-posed inverse ultrasonic scattering commonly used Tikhonov regularization, which considers error only in the data. The solution so obtained is not precise enough to reconstruct the quantitative internal structure of a large or high-contrast object. This paper adopts the truncated total least squares method, simultaneously considering error and noise on both sides of the inverse scattering equation, and compares it with the classical Tikhonov regularization. We show that it can substantially improve reconstruction fit and image quality when the inverse scattering equation system is strongly ill-posed.

Algorithms↗
PubMed2003

Expression of growth hormone receptor and its mRNA in hepatic cirrhosis.

AIM: To investigate the expression of growth hormone receptor (GHR) and mRNA of GHR in cirrhotic livers of rats with the intension to find the basis for application of recombinant human growth hormone (rhGH) to patients with liver cirrhosis. METHODS: Hepatic cirrhosis was induced in Sprague-Dawley rats by administration of thioacetamide intraperitoneally for 9-12 weeks. Collagenase IV was perfused in situ for isolation of hepatocytes. The expression of GHR and its mRNA in cirrhotic livers was studied with radio-ligand binding assay, RT-PCR and digital image analysis. RESULTS: One class of specific growth hormone-binding site, GHR, was detected in hepatocytes and hepatic tissue of cirrhotic livers. The binding capacity of GHR (R(T), fmol/mg protein) in rat cirrhotic liver tissue (30.8+/-1.9) was significantly lower than that in normal control (74.9+/-3.9) at the time point of the ninth week after initiation of induction of cirrhosis (n=10, P<0.05), and it decreased gradually along with the accumulation of collagen in the process of formation and development of liver cirrhosis (P<0.05). The number of binding sites (X10(4)/cell) of GHR on rat cirrhotic hepatocytes (0.86+/-0.16) was significantly lower than that (1.28+/-0.24) in control (n=10, P<0.05). The binding affinity of GHR among liver tissue, hepatocytes of various groups had no significant difference (P>0.05). The expression of GHR mRNA (riOD, pixel) in rat cirrhotic hepatic tissues (23.3+/-3.1) was also significantly lower than that (29.3+/-3.4) in normal control (n=10, P<0.05). CONCLUSION: The growth hormone receptor was expressed in a reduced level in liver tissue of cirrhotic rats, and lesser expression of growth hormone receptors was found in a later stage of cirrhosis. The reduced expression of growth hormone receptor was partly due to its decreased expression on cirrhotic hepatocytes and the reduced expression of its mRNA in cirrhotic liver tissue.

Acetamides↗
PubMed2003

[Trans-sacral local resection for rectal cancer].

OBJECTIVES: To evaluate the effect and the indication of local resection for rectal cancer below the peritoneal reflection. METHODS: One hundred and thirty-four patients with early rectal carcinoma whose masses were >or= 5 cm or <or= 7 cm apart from the anus border, eminence or surface shape, 1 - 3 cm in the diameter, and could be shook up and down or sideways at basal part. Trans-sacral local resection was performed in all patients. RESULTS: No recurrence appeared in 47 patients with intra-mucosal carcinoma (M-Ca). In 87 patients with submucosal carcinoma (SM-Ca), 3 patients were positive for the cutting end, 8 showed vessel infiltration, and 5 showed low-differentiated adenocarcinoma. These patients had to accept mile's operation, but one patient had local recurrence and 2 patients had liver metastases. Two patients had local recurrence and 8 had metastasis of the liver and other sites. The total 5-year survival rate was 94%. CONCLUSIONS: Trans-sacral local resection is an optimal operation since the operative range is small and artificial anus is avoided. However, it is only suitable for early rectal carcinoma. When vessel infiltration or low differentiation or positive cutting end are confirmed, radical operation should be added.

Adolescent↗