Biomedical subjects

Ji Li

Publications and source records attributed to Ji Li.

61 records · Page 4Linked to original sources

PubMed2002

Arsenic trioxide promotes histone H3 phosphoacetylation at the chromatin of CASPASE-10 in acute promyelocytic leukemia cells.

Arsenic trioxide (As(2)O(3)) is highly effective for the treatment of acute promyelocytic leukemia, even in patients who are unresponsive to all-trans-retinoic acid therapy. As(2)O(3) is believed to function primarily by promoting apoptosis, but the underlying molecular mechanisms remain largely unknown. In this report, using cDNA arrays, we have examined the changes in gene expression profiles triggered by clinically achievable doses of As(2)O(3) in acute promyelocytic leukemia NB4 cells. CASPASE-10 expression was found to be potently induced by As(2)O(3). Accordingly, caspase-10 activity also substantially increased in response to As(2)O(3) treatment. A selective inhibitor of caspase-10, Z-AEVD-FMK, effectively blocked caspase-3 activation and significantly attenuated As(2)O(3)-triggered apoptosis. Interestingly, the treatment of NB4 cells with As(2)O(3) markedly increased histone H3 phosphorylation at serine 10, an event that is associated with acetylation of the lysine 14 residue. Chromatin immunoprecipitation assays revealed that As(2)O(3) potently enhances histone H3 phosphoacetylation at the CASPASE-10 locus. These results suggest that the effect of As(2)O(3) on histone H3 phosphoacetylation at the CASPASE-10 gene may play an important role in the induction of apoptosis and thus contribute to its therapeutic effects on acute promyelocytic leukemia.

Acetylation↗

PubMed2002

A novel type I cytokine receptor is expressed on monocytes, signals proliferation, and activates STAT-3 and STAT-5.

Here we report the cloning of a novel type I cytokine receptor, gp130-like monocyte receptor (GLM-R), with homology to the interleukin-6 receptor signal transducing chain, gp130, and granulocyte colony-stimulating factor receptor. Human and murine GLM-R cDNAs encode open reading frames of 732 and 716 amino acids, respectively, and the corresponding genes are located in close proximity to gp130 genes on human chromosome 5 and mouse chromosome 13. GLM-R is specifically expressed on CD14-positive cells and is up-regulated more than 50-fold upon activation of those cells. To address the question of whether GLM-R is a signaling receptor, we constructed a chimeric molecule, consisting of the extracellular domain of human growth hormone (hGH) receptor, and the intracellular domain of GLM-R. When transfected into factor-dependent 32D cells, this chimeric molecule could signal for proliferation and activate signal transducer and activator of transcription (STAT)-3 and STAT-5 upon stimulation with hGH. Thus, GLM-R is a novel signaling receptor chain potentially involved in the development and function of monocytes and macrophages.

Amino Acid Sequence↗

PubMed2002

The carboxyl-terminal domains of MKP-1 and MKP-2 have inhibitory effects on their phosphatase activity.

Both the mitogen-activated protein kinase (MAPK) phosphatases MKP-1 and MKP-2 exert important feedback control of MAPK-mediated signaling events. The function of MKP-1 and MKP-2 is regulated via complex mechanisms, ranging from increased transcription of the MKP-1 and MKP-2 genes to post-translational catalytic activation of MKP-1 and MKP-2 proteins upon binding to their substrate MAPKs. In addition, MKP-1 stability increases upon ERK-dependent phosphorylation of two serine residues in its C-terminus. The C-terminal regions of MKP-1 and MKP-2, but not those of other MKPs, are homologous. To investigate the role of this domain, we have deleted the C-terminal tails from MKP-1 and MKP-2 and examined the effect of these deletions on their enzymatic activity. C-terminally truncated MKP-1 and MKP-2 exhibited, both in vivo and in vitro, substantially greater phosphatase activity towards their substrate MAPKs than did the full-length counterparts. However, C-terminal truncations did not significantly change either their substrate affinity, or their substrate-mediated catalytic activation. Basal phosphatase activity of the truncated proteins was also significantly higher than that of the wild-type counterparts. Collectively, these results suggest that the C-terminal domain may potentially play a role in the regulation of MKP-1 and MKP-2.

Amino Acid Sequence↗

PubMed2002

Effect of isoverbascoside, a phenylpropanoid glycoside antioxidant, on proliferation and differentiation of human gastric cancer cell.

AIM: To investigate the effects of phenylpropanoid glycoside antioxidant isoverbascoside on cell proliferation and differentiation of human gastric cancer cell line MGC 803. METHODS: MGC 803 cells were treated with isoverbascoside. Its effects on cell proliferation, tumorigenicity, enzymatic activities, cell cycles, and gene expression were respectively evaluated with cell counting, tumor formation assay, enzymatic assay, flow cytometer analysis, and Western blotting, with Me2SO as positive control. RESULTS: Isoverbascoside could markedly inhibit cell proliferation in dose- and time-dependent manner. Isoverbascoside 20 micromol/L strikingly suppressed cell tumorigenicity, activities of alkaline phosphatase (ALP), and lactate dehydrogenase (LDH), and caused G0/G1 arrest. The expression of G1 S checkpoint related proteins, p53, p21/WAF1, and p16/INK4, were up-regulated after MGC 803 cells were treated with isoverbascoside 20 micromol/L for 4-8 h. Contrarily, the expression of C-myc protein was suppressed after 8 h treatment. CONCLUSION: Isoverbascoside inhibited cell proliferation, reversed cell malignant phenotypic characteristics, and consequently caused differentiation in MGC 803 cells. These effects might be associated with its activities of causing G0/G1 arrest and regulating the expression of cell cycle related proteins.

Adenocarcinoma↗

PubMed2002

[Influence of needling at yin-yang meridian points on cerebral glucose metabolism].

OBJECTIVE: To study the different effect of needling at different meridian points (MP) on different cerebral functional regions by using positron emission tomography and cerebral function tracer 18F-fluorodeoxy glucose to observe the effect of electro-acupuncture (EA) stimulation at Yin MP or Yang MP on local cerebral glucose metabolism in 30 healthy volunteers. METHODS: The thirty subjects were randomly divided into 2 groups, the 12 subjects in the Yang MP group treated by needling at Hegu (LI4), Quchi (LI11), Zusanli (St36) and Shangjuxu (St37), the 18 subjects in the Yin MP group treated by needling at Neiguan (Pc6), Chize (Lu5), Sanyinjiao (Sp6) and Yinlingquan (Sp9). All the needling was conducted at one side of body. RESULTS: After needling at Yang MP, the cerebral glucose metabolism was elevated in bilateral cross region of frontal lobe and temporal lobe, parietal lobe, thalamus and basal ganglia, and in contralateral cerebellum and hippocampus. After needling at Yin MP, the cerebral glucose metabolism was lowered in bilateral cross region of frontal and temporal lobe, contralateral temporal lobe, cerebellum and thalamus, and was elevated in homolateral hippocampus and caudate nucleus. CONCLUSION: Under physiological condition, the regulatory effects of acupuncture on central nervous system would be different when needling at different MP.

Acupuncture Points↗

PubMed2002

[Valuation of forest damage cost from SO2 emission: a case study in Hunan Province].

Large amount SO2 emission caused serious damage of forest ecosystem in China and calculation of the damage cost is an important issue for policy-making. However, no applicable method was developed to estimate forest damage under different SO2 emission scenarios. Basing on previous field researches on sulfur-related forest impact in China and recent critical load mapping research, this paper presented a model for forest damage calculation by developing a dose-response function that related the damage to cumulative sulfur critical loads. This model was applied to the forests in Hunan, a province in acid rain control zone in China. Results showed that in the business-as-usual case, SO2 emission in Hunan will increase by 120% from 1995 (8.82 mil. ton) to 2020 (19.56 mil. ton), but damage cost will increase by 4.3 times, reaching 6.19 billion RMB in 2020. Results also showed the measures for SO2 control were cost-effective because the marginal damage cost will be about 6000 RMB per ton SO2 in 2020 in BAU case. At current SO2 emission level, marginal benefit will be about 1500 RMB per ton. Uncertainty analysis demonstrated that this model provides reasonable damage estimates and would therefore be applicable in a broad range of policy settings.

China↗

PubMedDate not supplied

Efficacy and safety of LASIK in 10,052 eyes of 5081 myopic Chinese patients.

PURPOSE: To analyze the outcomes and incidence of postoperative complications in a large series of patients undergoing LASIK for myopia. METHODS: All 5081 patients (10,052 eyes) diagnosed with myopia at The Third Hospital of Handan, China, from September 2003 through March 2005 were studied. All study eyes underwent LASIK with 1-month follow-up. Spherical equivalent refraction, best spectacle-corrected visual acuity (BSCVA), and uncorrected visual acuity (UCVA) were measured before and after surgery and intra- and postoperative complications were recorded. RESULTS: Uncorrected visual acuity at 1-month follow-up of 9555 (95.1%) eyes reached or exceeded the preoperative BSCVA. Hemorrhage of corneal limbus during surgery occurred in 1060 (10.5%) eyes, Sands of Sahara syndrome occurred in 232 (2.3%) eyes, interface infection responsive to treatment occurred in 4 (0.04%) eyes, and epithelial ingrowth occurred in 1 (0.01%) eye. CONCLUSIONS: LASIK is a safe and effective method for the treatment of myopia.

Adult↗