[Cytokine gene polymorphism and organ transplantation].
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Cytokines↗
Biomedical subjects
Y Tian
Publications and source records attributed to Y Tian.
Mechanism of suppression of cytochrome P-450 1A1 expression by tumor necrosis factor-alpha and lipopolysaccharide.
Proinflammatory cytokines, such as tumor necrosis factor (TNF)-alpha, interleukin-1beta, and lipopolysaccharides (LPS), suppress the gene expression of cytochrome P-450 1A1 (cyp1a1). The mechanism of the suppression is not well understood. In present study, we show that activation of nuclear factor-kappaB (NF-kappaB) is a critical event leading to the suppression of cyp1a1 gene expression, thus providing an underlying mechanism for the TNF-alpha- and LPS-induced cyp1a1 suppression. We demonstrated that: (i) inducible RelA expression down-regulated aryl hydrocarbon receptor (AhR) activated reporter gene; (ii) the suppressive effects of LPS and TNF-alpha on the AhR-activated reporter gene could be blocked by pyrrolidine dithiocarbamate, which is known to inhibit NF-kappaB action; and (iii) TNF-alpha and LPS-imposed repression could be reversed by the NF-kappaB super repressor (SRIkappaBalpha), thus demonstrating the specific involvement of NF-kappaB. Furthermore, nuclear receptor coactivators p300/CBP and steroid receptor coactivator-1 act individually as well as cooperatively to reverse the suppressive effects by NF-kappaB on the AhR-activated reporter gene, suggesting that these transcriptional coactivators serve as the common integrators for the two pathways, thereby mediating the cross-interactions between AhR and NF-kappaB. Finally, using the chromatin immunoprecipitation assay, we demonstrated that AhR ligand induces histone H4 acetylation at the cyp1a1 promoter region containing the TATA box, whereas TNF-alpha inhibits this acetylation, suggesting that AhR/NF-kappaB interaction converges at level of transcription involving chromatin remodeling.
Acetylation↗
Binding of p300/CBP co-activators by polyoma large T antigen.
Small DNA tumor viruses such as simian virus 40 (SV40) and polyomavirus (Py) take advantage of host cell proteins to transcribe and replicate their DNA. Interactions between the viral T antigens and host proteins result in cell transformation and tumor induction. Large T antigen of SV40 interacts with p53, pRb/p107/p130 family members, and the cyclic AMP-responsive element-binding protein (CREB)-binding protein (CBP)/p300. Py large T antigen is known to interact only with pRb and p300 among these proteins. Here we report that Py large T binds to CBP in vivo and in vitro. In co-transfection assays, Py large T inhibits the co-activation functions of CBP/p300 in CREB-mediated transactivation but not in NF-kappa B-mediated transactivation. p53 appears not to be involved in the functions of CREB-mediated transactivation and is not essential for large T:CBP interaction. Mutations introduced into a region of Py large T with homology to adenovirus E1A and SV40 large T prevent binding to the co-activators. These mutant large T antigens fail to inhibit CREB-mediated transactivation. The CBP/p300-binding Py mutants are able to transform established rat embryo fibroblasts but are restricted in their ability to induce tumors in the newborn mouse, indicating that interaction of large T with the co-activators may be essential for virus replication and spread in the intact host.
3T3 Cells↗
[Influence of cytokine gene polymorphism on renal transplantation].
OBJECTIVE: To investigate the influence of cytokine gene polymorphism on renal transplantation. METHODS: The cytokine genotypes of cytokines TNF-alpha, IL-10, TGF-beta(1), and L-6 among 91 consecutive kidney recipients were detected by PCR-SSP. The distribution frequencies of different cytokine genotypes and the influence of cytokine gene polymorphism on renal transplantation were analyzed. RESULTS: Among the 91 renal recipients, the dominant genotypes of IL-10 and TNF-alpha were low producer genotype with the frequencies of 90.1% and 79.1% respectively; and the dominant genotypes of TGF-beta(1) and IL-6 were high producer genotypes (79.1% and 100% respectively). The kidney recipients with TNF-alpha high producer genotype and IL-10 high or intermediate producer genotype were associated with more acute rejection episodes than those with low producer genotypes. The acute rejection episodes in the kidney recipients with IL-10 high or intermediate producer genotype were mainly vascular acute rejection. CONCLUSION: The cytokine gene polymorphism has significant influence on incidence and severity of acute rejection after renal transplantation. Detecting the cytokine genotype before renal transplantation is beneficial to predict the outcome of transplantation accurately.
Adolescent↗
[Expression of telomerase subunits and its relationship with telomerase activity in nasopharyngeal carcinoma].
OBJECTIVE: To study the expression of telomerase subunits and its relationship with telomerase activity in nasopharyngeal carcinoma. METHODS: The expression of telomerase subunits and the telomerase activity were examined in the same sample from nasopharyngeal carcinoma (NPC) as well as from chronic inflammation of nasopharyngeal epithelium (CINE) with RT-PCR and PCR-ELISA respectively. RESULTS: (1) hTERT mRNA was expressed in 38 of 43 cases of NPC (88%), and in none of the 16 cases of CINE (0%) (P < 0.05). (2) hTR was expressed in 39 of the 43 cases of NPC (90.7%),and in 14 of the 16 cases of CINE (87.5%) (P < 0.05). TP1 mRNA was expressed in 38 of the 43 cases of NPC (88%), and in 14 of the 16 cases of CINE (87.5%). There was no statistically significant difference between the expression of hTR and TP1 mRNA in NPC and their expression in CINE (P > 0.05). (3) Telomerase activity was detected in 37 of the 43 cases of NPC (86%) and in none of the 16 cases of CINE (0%) (P < 0.05). There was a significant correlation between the expression of hTERT mRNA in NPC and CINE (P < 0.05). No correlation was observed between telomerase activity and the expression of hTR and TP1 mRNA (P > 0.05). (5) No correlation was observed between the clinicopathological features of NPC and CINE (such as clinical stage and lymph node metastasis) and the expression of any of the telomerase subunits (P > 0.05). CONCLUSION: The expression of hTERT may play a critical role in regulation of telomerase activity, and detection of hTERT mRNA might be useful for clinical diagnosis of NPC.
Carcinoma, Squamous Cell↗
[A bivalent VP1 gene vaccine against Coxsackie virus B1/B3].
OBJECTIVE: To construct a bivalent VP1 gene vaccine against Coxsackie virus B1 and B3 (CVB1 and CVB3) and to test its immunogenicity in mice. METHODS: The VP1 gene of CVB1 was amplified by RT-PCR. The VP1 genes of CVB1 and of CVB3 under the control of cytomegalovirus (CMV) promoter and SV40 promoter respectively were inserted oppositely into the pCR3-Uni, a eukaryotic expression vector. The resultant bivalent gene vaccine plasmid was used to inoculate 3-week-old BALB/c mice. Immunofluorescence test and RT-PCR were conducted 24, 48, and 96 hours after the transfection. Sera of the tested animals were sampled at 0, 2, 4, and 6 weeks after the inoculation and detected for CVB-specific antibodies by ELISA. RESULTS: A bivalent gene vaccine plasmid of CVB1 and CVB3 was obtained. Samples of 4 and 6 weeks after the inoculation were shown to be CVB-antibody positive, while those of 0 and 2 weeks after the inoculation shown negative. CONCLUSION: The gene vaccine thus constructed induces CVB-speicific antibodies in mice, and can serve as gene vaccine candidate for human beings.
Animals↗
[The expression and clinical significance of pRB and E(2)F(1) in human neuroendocrine lung tumor].
OBJECTIVE: To investigate the role pRB and E(2)F(1) play in the cell cycle and the oncogenesis of human nemoendocrine lung fumor and the correlation between their expression and the invasiveness and prognosis of human neuroendocrine lung tumor. METHODS: Immunohistochemistry and in situ hybridization were used to detect the expression of pRB and E(2)F(1) mRNA in the paraffin embedded tissues of 78 cases of human neuroendocrine lung tumor. Statistics was used to analyze the data. RESULTS: The positive expression rate of pRB in both typical and atypical carcinoid was 87.5% (14/16). However, pRB was not expressed in large cell neuroendocrine carcinoma and small cell lung cancer (P < 0.001). The positive rate of E(2)F(1) mRNA expression in human neuroendocrine lung tumor was 87.2% (68/78). The strength of expression of pRB and E(2)F(1) was obviously correlated with the tumor stage, lymph node metastasis and prognosis (P < 0.05). CONCLUSION: The loss of pRB and E(2)F(1) overexpression may play a key role in the development of human neuroendocrine lung tumors.
Adult↗
Effect of photodynamic therapy (PDT) on the expression of pro-apoptotic protein Bak in nasopharyngeal carcinoma (NPC).
BACKGROUND AND OBJECTIVE: To investigate the effect of photodynamic therapy (PDT) on expression of the pro-apoptotic gene Bak in nasopharyngeal carcinoma (NPC). STUDY DESIGN/MATERIALS AND METHODS: Apoptosis and expression of the pro-apoptotic gene Bak on the tumor tissues from both pre- and post-PDT were determined using the in situ end labeling (ISEL), standard immunohistochemistry technique and western blot, respectively, in 24 patients with either persistent or recurrent NPC after radiotherapy. RESULTS: Before PDT, apoptotic index (AI) in tumor tissue was 1.2 +/- 0.6. At 6, 12, 24 and 48 hours after PDT, AI were 6.5 +/- 3.1, 23.6 +/- 8.3, 67.2 +/- 14.2 and 89.3 +/- 8.1, respectively. PDT caused apoptosis in a time-dependent fashion. Immunohistochemical assay indicated that 75% (18/24) of the patients had an upgrade expression of Bak protein in their tumor tissues after PDT. Increases in expression of Bak from PDT were also confirmed by western blot analysis. CONCLUSIONS: PDT probably causes NPC cell apoptosis through an upregulation of the pro-apoptotic protein Bak expression.
Adult↗
A modified method for preparation of adriamycin carried by magnetic albumin microspheres.
The targeting of antineoplastic agents to restricted anatomic sites and specific target cells have been challenged clinicians all the time in cancer chemotherapy, which resulted in recent efforts to focus the effects of existing antitumor agents and treatments on tumor cells and spare their effects on normal cells. The drug-carrier complex, adriamycin carried by magnetic albumin microspheres (ADM-MAM) was prepared by using our discovered new and modified method. The physical feature of the prepared drug-carrier microspheres was much better than by the traditional method in comparison. The successful preparation of the drug-carrier complex, ADM-MAM, is one of the key steps for our later further researches in the targeted chemotherapy.
Antineoplastic Agents↗
The influence of phorbol ester on the effect of tamoxifen in breast cancer cells.
To investigate the correlation between the activity of kinases in the growth factor signal transduction pathway and the development of resistance of breast cancer to tamoxifen, reporter gene regulated by the regulating fragment of CCD1 was transfected into the MCF-7 cells, and the influence of tamoxifen on the reporter gene expression was examined under different conditions of TPA treatment. Our results showed that the reporter gene expression was inhibited by tamoxifen and promoted by TPA. Furthermore, tamoxifen exerts an agonist effect on the reporter gene expression when the cells was treated by TPA previously for 12 h. It is concluded that TPA could induce estrogen-like effect of tamoxifen on estrogen receptor positive breast cancer cells and it may be one of the mechanisms responsible for the development of tamoxifen resistance.
Antineoplastic Agents, Hormonal↗
A simple flow-injection on-line clean-up system for microwave plasma-torch atomic emission spectrometry.
A simple flow injection (FI) on-line clean-up system has been developed for microwave plasma-torch atomic emission spectrometry (MPT-AES). A non-selective strongly acidic cation-exchange resin was used to achieve the goal of "on-line clean-up". Ag and Zr, which form halogen-complex anions in halide acid media, and Cr, Mo, and P, which exist as acid group anions or acids (neutral) in acidic solution, were determined and the interfering matrix cations were removed on-line. Satisfactory analytical results were obtained from some practical samples by use of this procedure.
Journal Article↗
A hypothesis on the metabolism of glyceryl trinitrate in vascular endothelial cells.
BACKGROUND: Extensive research has been conducted regarding the mechanism of action of glyceryl trinitrate (GTN). It is currently believed that GTN undergoes a thiol-dependent metabolic pathway and releases its active metabolite, nitric oxide (NO) and/or S-nitrosothiols (R-SNO). This activates guanylyl cyclase (GC) leading to the formation of cGMP, which is responsible for the relaxation of vascular smooth muscles and the inhibition of platelet aggregation. The lack of knowledge as to the precise mechanism of GTN action and the modulation of its formation has limited the prevention of tolerance to GTN. RESULTS: With cultured human vascular endothelial cells (EC), we showed that nitrite was first formed in endothelial cells whose concentration was dependent on reduced thiols. Cells preexposed to GTN significantly decreased the production of nitrite compared with cells that were not preexposed. Furthermore, we showed that thiols in cultured cells were oxidized during interaction with GTN, which correlated with the time of exposure to GTN. CONCLUSION: Nitrite is the first active intermediate of GTN metabolism in endothelial cells. The analysis of the changes of the blood nitrite and reduced thiols concentration is helpful for evaluating the vasodilatation activity of GTN during therapeutic treatments.
Buffers↗
Effects of cryoanalgesia on post-thoracotomy pain and on the structure of intercostal nerves: a human prospective randomized trial and a histological study.
OBJECTIVE: The choice of analgesia in the management of post-thoracotomy pain remains controversial. Although several alternative forms of post-thoracotomy analgesia exist, all have their disadvantages. Cryoanalgesia, localized freezing of intercostal nerves, has been reported to have variable effectiveness and an incidence of long-term cutaneous sensory changes. We carried out an animal study to assess the reversibility of histological changes induced by cryoanalgesia and a prospective randomized trial to compare the effectiveness of cryoanalgesia with conventional analgesia (parenteral opiates). METHODS: In six anaesthetized dogs, intercostal nerves were exposed to a varying duration of cryo-application (30, 60, 90 and 120 s). The nerves were biopsied and examined histologically at regular intervals over the following 6 months. In the clinical study, 200 consecutive patients undergoing thoracotomy were randomized to cryoanalgesia and conventional (parenteral opiates) analgesia groups. Postoperative pain scores, respiratory function tests and use of opiate analgesia were measured for the two groups. RESULTS: Following application of the cryoprobe, degeneration and fragmentation of the axons was evident with associated inflammatory changes. As the endoneurium remained intact, axonal regeneration took place after the resolution of axonal swelling. Over the course of weeks, recovery of the intercostal nerve occurred and was complete after 1 month for the 30 and 60 s groups. For nerves exposed to longer durations of cryoanalgesia, the time taken for complete recovery was proportionally increased. Clinically, there was a statistically significant (P<0.05) improvement in postoperative pain scores and use of opiate analgesia and an improvement (P>0.05) in respiratory function tests for patients in the cryoanalgesia group. The previously suggested cutaneous sensory changes resolved within 6 months with complete restoration of function. CONCLUSIONS: We suggest that cryoanalgesia be considered as a simple, inexpensive, long-term form of post-thoracotomy pain relief, which does not cause any long-term histological damage to intercostal nerves.
Adult↗
The relationship between structures and in vitro properties of a polyanhydride implant containing gentamicin sulfate.
Laboratory scale injection-molding equipment was utilized to fabricate an implant consisting of poly(FAD:SA 1:1) and 20% (w/w) gentamicin sulfate. Characterizations were performed to determine the molecular weight and glass transition temperature of poly(FAD:SA 1:1). A study was carried out to investigate the relationships between the in vitro performance, morphology, and micro-structures of the molded implants. It was found that implants produced with different structures exhibited different physical integrities in water, i.e., cracking or non-cracking. For the non-cracking implants, a skin-core structure formed by an oriented skin layer was observed under a polarized light microscope. The same morphology was not seen in the cracking implants. The crystal orientation in the skin layer of the non-cracking implants was further identified using a wide-angle x-ray diffraction method (WAXD). No crystal orientation could be found in the cracking implants by WAXD. Furthermore, studies were carried out to evaluate the in vitro drug release for implants showing different degrees of integrity in water. The in vitro drug release of the cracking implants was markedly faster than that of the non-cracking implants due to the pronounced initial drug-burst effect as a result of crack formation in the implants.
Absorbable Implants↗
Purification, crystallization and preliminary X-ray data for Escherichia coli GlmU: a bifunctional acetyltransferase/uridyltransferase.
Crystals of Escherichia coli GlmU, a bifunctional enzyme catalyzing the acetylation of glucosamine-1-phosphate and uridylylation of N-acetylglucosamine-1-phosphate to produce UDP-GlcNAc, have been prepared in complex with coenzyme A and UDP-GlcNAc. These crystals belong to space group R32, with unit-cell parameters a = 104.5, c = 648.2 A, diffract to at least 2.1 A resolution and may contain two subunits of the trimeric enzyme per asymmetric unit.
Crystallization↗
Protein kinase C and calcium regulation of adenylyl cyclase in isolated rat pancreatic islets.
Rat islets express several isoforms of adenylyl cyclase (AC), and the regulation of AC activity in isolated islets by Ca(2+) and protein kinase C (PKC) was investigated. At basal 2.8 mmol/l glucose, the muscarinic receptor agonist carbamylcholine chloride (CCh) evoked a concentration-dependent increase in cAMP generation with a maximum increase at least 4.5-fold above control. In contrast, forskolin and glucagon-like peptide 1 fragment 7-36 amide increased cAMP accumulation 23-fold and almost 10-fold, respectively. Cholecystokinin 26-33 sulfated amide (CCK) also stimulated cAMP production by up to eightfold, as did the phorbol ester, phorbol 12,13-dibutyrate (PDBu). PDBu and CCh or CCK responses were not additive. The effects of phorbol ester, CCh, and CCK were inhibited by as much as 75% by the PKC inhibitors GF 109203X and Ro-32-0432 and after PKC downregulation. In the absence of extracellular Ca(2+), PDBu-, CCh-, and CCK-induced cAMP production was inhibited by approximately 50% in each case. Chelation of intracellular Ca(2+) with 1,2-bis(o-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester (BAPTA/AM) inhibited CCh- and CCK-stimulated cAMP generation by approximately 50% but did not inhibit the stimulatory effect of PDBu. Stringent Ca(2+) depletion by removal of extracellular Ca(2+) and inclusion of BAPTA/AM allowed for increased cAMP production in response to CCh and CCK; PKC inhibitors and PKC downregulation prevented this stimulation. Glucose stimulation also increased islet cAMP production, but PDBu did not potentiate the glucose response. The results suggest that Ca(2+) influx, Ca(2+) mobilization, and PKC activation play important roles in the modulation of AC activity in pancreatic islets.
Adenylyl Cyclases↗
[Effect of methionine supplementation on the selenium bioavailability in rats fed on grains from Keshan disease endemic area].
In order to study the effect of dietary methionine on tissue selenium and glutathione peroxidase activity(GPX) in rats fed on grains from Keshan Disease endemic area, a nonpurified selenium (Se) deficient diet (containing Se 0.007 mg/kg diet) taken from Keshan Disease endemic area was supplemented with selenomethionine (SeMet) to provide selenium content in diet for 0.007, 0.06 and 0.50 mg/kg and added or not added with DL-methionine (Met) 4 g/kg to make 6 kinds of diet. Fifty four male weanling Wistar rats were randomly divided into 6 groups, consuming each one of the 6 diets for 8 weeks. The Se content and GPX activity in tissues of animals with Met supplementation were compared with those without Met supplementation. The results showed that adding Met did not result in significant changes of tissue Se content and GPX activity in animals having dietary Se of 0.007 mg/kg, except for lower muscle Se content. However, in animals having dietary Se of 0.06 mg/kg and supplementing Met resulted in selenium redistribution in tissues-decrease of Se content in muscle, increase of Se content in liver and blood and significant elevation of GPX activity in all tissues. In animals having methionine-added and dietary Se of 0.50 mg/kg, tissue Se content declined to various extent, while GPX activity remained unchanged. The results suggest that SeMet (main chemical form of Se in cereals) is preferentially incorporated into body protein when dietary methionine is limited. Once Met is supplemented, dietary SeMet would provide more Se for the syntheses of GPX and other selenoproteins. The results further suggest that marginal deficiency in sulfur-containing amino acids in the diet from Keshan Disease endemic area might be an additional factor for the development of Keshan Disease under selenium deficiency.
Animals↗
[The cytotoxic effects of the adriamycin magnetic albumin microspheres combined with external magnetic fields on the malignant tumor cells].
This study sought to assess the inhibitory effects of the adriamycin magnetic albumin microspheres (ADM-MAMs) on Walker-256 malignant tumor cells in vitro induced by the permanent magnetic fields. The cultured Walker-256 cells were divided into three groups; the group of ADM-MAMs combined with magnetic fields, the group of AMD-MAMs without magnetic fields, and ADM group. The growth states of the cells were observed and photographed under the inverted microscope. The inhibitory rates(IR) were assayed by the modified MTT colorimetric method. The results showed that the IR of the ADM-MAMs group were similar to those of the ADM group (P > 0.05), but the group of ADM-MAMs combined with magnetic fields had obviously higher IR and significant changes of the cells' shapes. These findings indicate that the anticancer effect of ADM-MAMs on malignant tumor cells is similar to that of ADM, and such effect can be increased by the combined use of ADM-MAMs and external magnetic fields.
Albumins↗