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Biomedical subjects

X Cao

Publications and source records attributed to X Cao.

At least 73 records · Page 4Linked to original sources
PubMed2001

Significant augmentation of pro-apoptotic gene therapy by pharmacologic bcl-xl down-regulation in mesothelioma.

The ratio of pro-apoptotic (PAP) and anti-apoptotic (AAP) bcl-2 proteins is important in apoptosis regulation. We sought to determine if inhibition of the AAP bcl-xl by sodium butyrate (SB) would augment apoptotic cellular death in mesothelioma when combined with adenoviral pro-apoptotic gene therapy (PAGT) by simultaneously increasing PAP and decreasing AAP in these cells. Human mesothelioma cell lines were exposed to AdBax, AdBak, Adp53, and SB alone as well as all vectors combined with SB at varying doses and time points. Cell death was assessed, and apoptosis evaluated by morphology and FACS. Isobologram analysis evaluated additive or synergistic effect. Cellular death and apoptosis were augmented by PAGT/SB combinations compared to monotherapy. Following AdBax/SB and AdBak/SB, a decrease of the AAP bcl-xl was noted in combination with increases in PAP bax and bak. By isobologram analysis, additive or synergistic cell killing was noted with both combinations. SB treatment did not significantly augment cell killing or apoptosis in combination with Adp53. PAGT/SB was more effective than monotherapy in induction of apoptotic cell death. Synergy may be due to the ability of SB to decrease bcl-xl with marked increases in PAP engendered by PAGT. Combination therapy with agents that down-regulate AAP in addition to PAGT may prove useful clinically.

Adenoviridae↗
PubMed2001

Intratumoral IL-18 gene transfer improves therapeutic efficacy of antibody-targeted superantigen in established murine melanoma.

Antibody-targeted superantigen C215Fab-SEA is a fusion protein of staphylococcal enterotoxin A (SEA) and the Fab region of the tumor-reactive C215 mAb. It can trigger CTL against C215 antigen-positive tumor cells and induce tumor-suppressive cytokines. However, the antitumor effect of C215Fab-SEA is not satisfactory because of suboptimal production of Th1 cytokines after repeated administration. Interleukin 18 (IL-18) is a novel cytokine with profound effects on Th1 cellular response. In this study, we showed that adenovirus-mediated intratumoral IL-18 gene transfer strongly improved the therapeutic efficacy of C215Fab-SEA in the pre-established C215 antigen-expressing B16 melanoma murine model. More significant tumor inhibition and prolonged survival time were observed in tumor-bearing mice received combined therapy of C215Fab-SEA and Ad IL-18 than those of mice treated with C215Fab-SEA or AdIL-18 alone. Combination therapy augmented NK and CTL activities of tumor-bearing mice more markedly. The production of IL-2 and IFN-gamma also increased more significantly. More potent antitumor effect of combined therapy was observed in IL-10 KO mice with enhanced Th1 response. Our data demonstrated that the antitumor effect of C215Fab-SEA immunotherapy could be potentiated significantly by combination with intratumoral IL-18 gene transfer through more efficient activation of Th1 immune responses.

Adenoviridae↗
PubMed2001

Intrasplenic transplantation of IL-18 gene-modified hepatocytes: an effective approach to reverse hepatic fibrosis in schistosomiasis through induction of dominant Th1 response.

Hepatic fibrosis is a common outcome of chronic liver diseases. In schistosomiasis, chronic parasite egg-induced granuloma formation can lead to fibrosis, which is immunologically characterized by the dominant Th2 response. Recently, it has been shown that gene therapy is an attractive approach for the treatment of hepatic fibrosis. To investigate the antifibrotic effects of IL-18 gene transfer, a normal murine liver cell line BNL.CL2 was transfected with recombinant adenovirus encoding mouse IL-18, and then intrasplenically transplanted into mice infected with Schistosoma japonicum (S. japonicum). Our data show that IL-18 gene-modified hepatocytes intrasplenically transplanted into mice can effectively express IL-18 in the liver and in peripheral blood. Intrasplenic transplantation of IL-18 gene-modified hepatocytes into S. japonicum-infected mice could result in a significantly increased IFN-gamma and IL-2 but decreased IL-4 and IL-10 concentration both in the liver and in the serum, suggesting that the dominant Th2 response in mice with schistosomiasis could be reversed by this intervention. Consistent with the changes in Th1 and Th2 cytokine production, mice intrasplenically transplanted with IL-18 gene-modified hepatocytes developed much less hepatic fibrosis at 20 weeks after infection, which was evaluated by liver content of hydroxyproline, collagens, and hepatic mRNA expression of procollagens. These data indicate that intrasplenic transplantation of IL-18 gene-modified hepatocytes can be a candidate for therapeutic intervention in hepatic fibrosis through induction of a dominant Th1 response.

Adenoviridae↗
PubMed2001

IFN-gamma gene therapy by intrasplenic hepatocyte transplantation: a novel strategy for reversing hepatic fibrosis in Schistosoma japonicum-infected mice.

Liver-targeted gene therapy using hepatocyte as recipient cells has recently been documented to be effective in treatment of numerous hepatic diseases, such as metabolic diseases and liver carcinoma. IFN-gamma elicits antipreliferative and antifibrogenic activity in a variety of mesenchymal cells, including hepatic satellite cells. To investigate the antifibrogenic response of liver gene therapy mediated by intrasplenic transplantation of gene-modified hepatocytes, normal mouse liver cell line BNL CL.2 cells were transfected with murine IFN-gamma gene (BNL.IFN-gamma) in vitro, and transplanted intrasplenically into Schistosoma japonicum-infected mice. The amounts and distribution of IFN-gamma (which inhibits collagen synthesis), TGF-beta (which stimulates collagen synthesis) and extracellular matrix, including type I and III collagen, were detected. In mice infected with S. japonicum and then treated with BNL.IFN-gamma, an increase of IFN-gamma and decrease of TGF-beta1 were detected at 20 weeks postinfection compared to untreated S. japonicum-infected mice. Immunohistochemical analysis showed that S. japonicum infection induced a marked increase of type I and III collagen synthesis. Whereas, 4 weeks after treatment with BNL.IFN-gamma, net synthesis rates of type I and III collagen were markedly decreased in the liver of infected mice. In addition, a decreased expression of TGF-beta1 and its receptor TGF-betaRII in the liver of BNL.IFN-gamma-treated mice was also observed. Moreover, the decrease in TGF-beta1 and TGF-betaRII protein approximately paralleled the decrease in their mRNA expression, which was detected by RNA dot blotting. The data indicate that intrasplenic transplantation of IFN-gamma gene-modified hepatocyte can be a candidate approach to treat hepatic fibrosis.

Animals↗
PubMed2001

Ovulation in the tree shrew (Tupaia belangeri) induced by gonadotrophins.

The induction of ovulation by exogenous gonadotrophins is an important approach for recovering oocytes used for studies on the reproductive biology of some mammals. In the present study, pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (hCG) were used to induce ovulation in the tree shrew (Tupaia belangeri) using the following regimens. Groups A1-A3, multiple injections of PMSG (30-60 IU) followed by a single dose of hCG (30-60 IU); B1, combination of a single injection of PMSG (60 IU) with a single dose of hCG (60 IU); E1, combination of a single injection of PMSG (60 IU) with a single dose of hCG (30 IU) plus PMSG (30 IU); and administration of either PMSG (C1 and C2) or hCG (D1). The ovulation rate of animals producing oocytes with either first polar body or distinct perivitelline space, and the mean number of oocytes per animal were considered the most important criteria in each regimen. The most effective induction of ovulation was achieved in groups B1 and E1, with ovulation rates of 4/4 and 4/4, respectively, and mean numbers of ovulated oocytes per animal of 3.25 +/- 0.48 and 4.00 +/- 0.71 respectively. No ovulation was observed in the control group or in group D1. Therefore, regimes B1 and E1 were considered as the simplest and most effective for the induction of ovulation in the tree shrew.

Animals↗
PubMed2001

Determination of menadione sodium bisulfite in pharmaceutical preparations by flow-injection on-line photochemical spectrofluorometry.

A flow-injection on-line photochemical spectrofluorometry (FI-PF) was developed for the determination of menadione sodium bisulfite (MSB) using acetone and sodium sulfite as sensitizing reagents. An injected sample band carried by a water stream was on-line merged with a mixed NaOH, Na2SO3 and acetone solution in a "T" connector. It was then driven to pass a knotted PTFE photochemical reactor (0.5 mm i.d. x 200 cm, KR) that was freely coiled around a 6-W low-pressure mercury lamp. While passing the KR, MSB was derived into an intensively fluorescent compound that was on-line delivered into a flow-through cell and detected therein at an emission wavelength of 459 nm and an excitation wavelength of 336 nm. Under optimized conditions a detection limit of 0.38 microg l(-1) was achieved at a sampling rate of 90 h(-1). Eleven determinations of 0.5 mg l(-1) and 0.05 mg l(-1) MSB standard solution gave RSDs of 0.75% and 1.3%, respectively. The calibration curve was linear in the MSB concentration range 0.005-1.5 mg l(-1). The proposed method was successfully applied to assay the MSB content in MSB injection.

Flow Injection Analysis↗
PubMed2001

Genetic approach to insight into the immunobiology of human dendritic cells and identification of CD84-H1, a novel CD84 homologue.

To better understand the immunobiology of dendritic cells (DCs), we took the expressed sequence tag (EST) approach to describe their transcript profile and discovered novel genes. ESTs (n = 25,668) were generated from monocyte-derived DCs, and 15,863 ESTs (61.8%) represented unique genes in GenBank. Integration of ESTs allowed for the generation of a profile of 4,367 known genes and identification of > 100 novel genes. HLA-DR invariant chain p33, cathepsin D, HLA-DR alpha chain, beta2-microglobulin, HLA-DP beta chain, CD11a, and mannose receptor were in the top 30 transcripts, and 451 known genes were potentially associated with the immunobiology of DCs. This transcript profile was consistent with the unique antigen-presenting capacity of DCs and provided invaluable information to better understand the immunobiology of DCs. On the basis of the EST database, a full-length novel gene was identified that exhibited close homology with CD84; it was designated CD84-H1. The full-length cDNA of CD84-H1 contained an open reading frame of 870 bp encoding a type I transmembrane protein of 289 amino acids. Consistent with the structural feature of the CD2 family, the predicted 270-amino acid mature protein of CD84-H1 contained two extracellular immunoglobulin-like domains that shared homology with CD2 family members, e.g., CD84, Ly-9, CD48, and signaling lymphocyte activation molecule. Its intracellular domain was short and contained no putative signaling structure. Northern blot analysis revealed that CD84-H1 expression was predominantly restricted in hematopoietic tissues. Reverse transcription-PCR analysis showed that it was widely expressed in the immune cells, including monocytes, DCs, B cells, and T cells. These data indicate that CD84-H1 may be relevant to immune responses.

Adult↗
PubMed2001

Development and certification of a coal fly ash certified reference material for selected polycyclic aromatic hydrocarbons.

The development and certification of a coal fly ash certified reference material (CRM) for polycyclic aromatic hydrocarbons (PAH) is described; this is the first natural matrix CRM for organic environmental analysis in China. The homogeneity and stability of this material have been tested by HPLC. The concentrations of several PAH were determined by use of two independent, different methods--solvent extraction-HPLC analysis with UV detection coupled with fluorescence detection (FLD) and solvent extraction, isolation with a silica column, and GC analysis with flame ionization detection (FID). Five certified values were determined: phenanthrene 7.1 +/- 2.6 microg g(-1), anthracene 2.0 +/- 0.8 microg g(-1), fluoranthene 7.4 +/- 1.9 microg g(-1), pyrene 7 +/- 2 microg g(-1), and benzo[a]pyrene 1.3 +/- 0.3 microg g(-1). Reference values for several other PAH are also suggested.

Carbon↗
PubMed2001

[Automatic analysis and research on the trend of ST-T segment based on KL transform].

In view of the limitation of monitoring the trend of ST segment with the traditional method(ST level), we introduce a new monitor method based on KL transform. This method has overcome many disadvantages of ST level, e.g. the susceptibility to interference, a large variation of performance and the reflection of isolated characteristic. This method can characterize the signals stably and adequately. We have made experiment and analyzed the property of this method by using the standard database. The results indicate that the KL transform is of great clinical significance in detecting and monitoring the abnormality of the ST-T segment waveform over a long period of time, and the effect of monitor is also laid on the selection of KL series.

Electrocardiography↗
PubMed2001

[Immunological mechanism of human alpha-interferon gene therapy for treatment of melonoma].

OBJECTIVE: To investigate the possibility of alpha-INF gene therapy for treatment of melonoma. METHODS: An experimental model of fibroblast-mediated human alpha-IFN gene therapy was established for treatment of melonoma and the activity of NK and M phi was determined. RESULTS: The NK and M phi activity was increasing significantly after the implantation of alpha-IFN secreted by cloning the fibroblast in vivo. Good therapeutic results could be achived if the NIH3T3-IFN-alpha+ cells were combined with the IL-2/AK. CONCLUSION: The results has indicated that the fibroblast-mediated gene therapy could be good to use it for the treatment of human melonoma. More effective results could be achieved by using it in combination with IL-2.

3T3 Cells↗
PubMed2001

Endocytic routes of exogenous antigen in murine dendritic cells and macrophages.

OBJECTIVE: To compare the endocytic routes of exogenous antigen between murine dendritic cells (DCs) and macrophages (M phi s). METHODS: Murine bone marrow-derived DCs and peritoneal M phi s were pulsed with horseradish peroxidase (HRP)-5 nm colloidal gold for 10 minutes, then grouped and chased for 0-120 minutes in culture medium. Intracellular distribution of 5 nm colloidal gold was explored by means of the cellular enzymatic-chemistry of acid phosphatase and MHC II immuno-cytochemistry under electron microscope. RESULTS: After 10 minutes of pulse with HRP-5 nm colloidal gold and 30 minutes of chase, most HRP-5 nm gold particles internalized by DCs entered into MHC class II compartments (M II Cs), and a small portion entered into acid phosphatase-positive lysosomes. In contrast to DCs, most M phi s lysosomes were accessed by HRP-5 nm gold particles, and a small portion of HRP-5 nm gold particles entered into M II Cs. After 60 minutes of chase, 5 nm gold particles could hardly be seen within M phi s, whereas most 5 nm gold particles were still retained in DCs. CONCLUSIONS: The endocytic route of exogenous antigen in DCs seems to be different from that in M phi s. Antigens taken by M phi s mainly enter into lysosomes within 30 minutes. In the case of DCs, most internalized antigens enter into M II Cs, which may be related to their unique antigen-presenting function. In addition, M phi s seem to have more powerful capacity to scavenge exogenous antigen than DCs.

Acid Phosphatase↗
PubMed2001

Effects of acute or prolonged exposure to leptin on hepatic glucose oxidation.

OBJECTIVE: To observe the short-term and long-term effects of leptin on hepatic glucose oxidation and glucokinase gene expression. METHODS: Rat hepatic cell line BRL was incubated with leptin of different doses (range from 10 ng/ml-200 ng/ml) for 1 h or 24 h. Glucose oxidation was determined by liquid scintillation counting. Glucokinase gene expression (corrected by beta-actin) was determined by reverse transcription semi-quantitative polymerase chain reaction. RESULTS: Treatment with leptin 10 ng/ml for 1 h had no significant effects on glucose oxidation in hepatic cells. However, at the doses ranging from 50 ng/ml to 200 ng/ml, leptin significantly inhibited glucose oxidation. These effects disappeared when the hepatic cells were exposed to leptin for 24 h. Glucokinase mRNA expression was reduced significantly after both 1 h and 24 h exposure to leptin (100 ng/ml) as compared to that of the control group. CONCLUSION: A low dose of leptin has no significant effect on glucose oxidation in hepatic cells. A relatively high dose of leptin has an acute inhibitory effect on the glucose oxidation in hepatic cells. This effect may likely involve the inhibition of glucokinase gene expression. The inhibitory effect on glucose oxidation is transient and disappears with prolonged exposure time.

Animals↗
PubMed2001

Peri-operative treatment of most severely head-injured patients.

OBJECTIVE: To summarize the peri-operative experience from 53 patients with traumatic head injuries with GCS score 3-5. METHODS: Fifty-three most severely head-injured patients with GCS score 3-5 were admitted to our department and treated operatively from Oct. 1994 to Jun. 1998 and the data were analyzed retrospectively. RESULTS: Thirty-seven cases (69.8%) survived, among them 28 (52.8%) had a good recovery or moderate disability, and 9 (17%) had severe deficits. The other 16 (30.2%) died after therapy. CONCLUSIONS: The prognosis of most severely head-injured patients could be improved by peri-operative treatment including premedical care, early evacuation of intracranial hematoma with large decompressive craniectomies, intracranial hypertension monitoring, moderate hypothermia therapy, effective prevention and treatment of cerebral vasospasm and complications.

Adolescent↗
PubMed2001

[Effects of cervical vertebra rehabilitation pill on antiinflammation and analgesia].

OBJECTIVE: To study the effects of cervical vertebra rehabilitation pill on anti-inflammation and analgesia. METHODS: Hot board and body distortion induced by acertic acid methods were applied in mice for analgesia experiment. Granuloma induced by cotton ball implantation tumefaction in feet induced by carrageenin in rats and auricle tumefaction induced by croton oil in mice were applied for anti-flammation experiment. RESULTS: Cervical vertebra rehabilitation pill could significantly prolong the latent period of pain reaction induced by hot board in mice and markedly decrease the frequency of body distortion induced by acertic acid. Cervical vertebra rehabilitation pill also could significantly inhibit the tumefaction in feet induced by carrageenin, reduce the degree of tumefaction in auricle induced by croton oil in mice and inhibit the formation of granuloma induced by cotton ball implantation in subcutaneous part. CONCLUSION: Cervical vertebra rehabilitation pill has significant effects on anti-inflammation and analgesia.

Analgesics↗
PubMed2001

[Percutaneous testicular sperm aspiration and intracytoplasmic sperm injection in the treatment of severe male infertility].

OBJECTIVE: To investigate the efficacy of intracytoplasmic sperm injection (ICSI) combined with percutaneous testicular sperm aspiration (PTSA) in the treatment of severe male infertility. METHODS: From October 1998 to December 2000, 162 couples were enrolled, and ICSI and PTSA were adopted. Ovarian stimulation was achieved by the short protocol. All metaphase II (M II) oocytes were selected for ICSI. RESULTS: 1,517 M II oocytes were injected in 185 cycles, 990 fertilized (65.3%), and 152 embryo implanted. 54 couples achieved clinical pregnancy (35.5%). CONCLUSION: PTSA combined with ICSI is a rapid, convenient, painless and effective approach for the treatment of severe male infertility.

Adult↗
PubMed2001

[Reconstruction of heel: long-term follow up of 12 cases].

OBJECTIVE: To study long-term follow up result of fibula transplantation to reconstruct partial or complete defect of the heel. METHODS: Heel defects were reconstructed by means of reverse transferring of combined vascular pedicled fibulaflap. The calcaneus was repaired by two segments of the fibula. Skin defects were covered by skin flap, and sensation was restored by anastomosing the sural nerve and medial pedal nerve. The residual cavity was filled by muscles surrounding the fibula to reconstruct the appearance of foot. RESULTS: Four patients with complete heel defect and 8 with partial defect were operated on successfully. Two to 13 years(average 5.2 years) follow-up showed that the function and appearance of foot were normal and adaptive changes happened in the tissue of foot. The fibula was getting into a real cal caneous gradually. Besides this, the skin was thickened and the sensation was restored with the two-point discrimination of 0.8 to 3.0 cm. All patients resumed physical work. Comprehensive evaluation revealed that 11 patients were excellent and 1 was good in their functional recovery. CONCLUSION: The results suggested that this operation is ideal for reconstructing heel defect. All kinds of tissues in heel can be reconstructed and more satisfactory function and appearance can be obtained through adaptive heel reshaping along with long-term walk.

Adolescent↗
PubMed2001

[Relationship between the expression of Bax and apoptosis induced by hyperthermia in BcaCD885 cells].

OBJECTIVE: This study aimed to investigate the role of Bax gene in apoptosis induced by hyperthermia in BcaCD885 cells. METHODS: After inducing apoptosis through hyperthermia, the expression of Bax protein and mRNA were examined with FCM antibody analysis and RT-PCR technique respectively. RESULTS: Up regulation of Bax protein was noted after hyperthermia. The correlation coefficient r between the apoptotic rate and the expression Bax protein was 0.9240. The expression of Bax mRNA was also raised after hyperthermia. CONCLUSION: Hyperthermia acting as an external signal may up-regulates expression of Bax gene and then induces apoptosis in BcaCD885 cells.

Apoptosis↗