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Biomedical subjects

Jun Li

Publications and source records attributed to Jun Li.

At least 595 records · Page 33Linked to original sources
PubMed2002

Wild-type TP53 inhibits G(2)-phase checkpoint abrogation and radiosensitization induced by PD0166285, a WEE1 kinase inhibitor.

The WEE1 protein kinase carries out the inhibitory phosphorylation of CDC2 on tyrosine 15 (Tyr15), which is required for activation of the G(2)-phase checkpoint in response to DNA damage. PD0166285 is a newly identified WEE1 inhibitor and is a potential selective G(2)-phase checkpoint abrogator. To determine the role of TP53 in PD0166285-induced G(2)-phase checkpoint abrogation, human H1299 lung carcinoma cells expressing a temperature-sensitive TP53 were used. Upon exposure to gamma radiation, cells cultured under nonpermissive conditions (TP53 mutant conformation) underwent G(2)-phase arrest. However, under permissive conditions (TP53 wild-type conformation), PD0166285 greatly inhibited the accumulation of cells in G(2) phase. This abrogation was accompanied by a nearly complete blockage of Tyr15 phosphorylation of CDC2, an increased activity of CDC2 kinase, and an enhanced sensitivity to radiation. However, under permissive conditions (TP53 wild-type conformation), PD0166285 neither disrupted the G(2)-phase arrest nor increased cell death. The compound inhibited Tyr15 phosphorylation only partially and did not activate CDC2 kinase activity. To understand the potential mechanism(s) by which TP53 inhibits PD0166285-induced G(2)-phase checkpoint abrogation, two TP53 target proteins, 14-3-3rho and CDKN1A (also known as p21), that are known to be involved in G(2)-phase checkpoint control in other cell models were examined. It was found that 14-3-3rho was not expressed in H1299 cells, and that although CDKN1A did associate with CDC2 to form a complex, the level of CDKN1A associated with CDC2 was not increased in response to radiation or to PD0166285. The level of cyclin B1, required for CDC2 activity, was decreased in the presence of functional TP53. Thus inhibition of PD0166285-induced G(2)-phase checkpoint abrogation by TP53 was achieved at least in part through partial blockage of CDC2 dephosphorylation of Tyr15 and inhibition of cyclin B1 expression.

Cell Cycle Proteins↗
PubMed2002

Antitumor activities of human dendritic cells derived from peripheral and cord blood.

AIM: To observe the biological specialization of human peripheral blood dendritic cells (DC) and cord blood derived DC and its effects on effector cells killing human hepatocarcinoma cell line BEL-7402. in vitro. METHODS: The DC biological characteristics were detected with immunohistochemical and MTT assay. Two antitumor experiment groups are divided: peripheral blood DC and cord blood DC groups. Peripheral blood DC groups used LAK cells as the effector cells and BEL-7402 as target cells, while cord blood DC groups used CTL induced by tumor antigen twice pulsed DC as effector cells and BEL-7402 as target cells, additional peripheral blood DC and cord blood DC are added to observe its stimulating activities to effector cells. The effector's cytotoxicity to tumor cells were detected with neutral red colorimetric assay at two effector/target ratios of 5:1 and 10:1. RESULTS: Peripheral blood DC and cord blood DC highly expressed HLA-ABC, HLA-DR, HLA-DQ, CD54 and S-100 protein. The stimulating activities to lymphocyte proliferation were compared between experimental groups (DC added) and control group (no DC added), in six experiment subgroups,the DC/lymphocyte ratio was sequentially 0.25:100, 0.5:100, 1:100, 2:100, 4:100 and 8:100.A values were sequentially 0.75396+/-0.009, 0.84916+/-0.010, 0.90894+/-0.012, 0.98371+/-0.007, 1.01299+/-0.006 and 1.20384+/-0.006 in peripheral blood DC groups and 0.77650+/-0.005, 0.83008+/-0.007, 0.92725+/-0.007, 1.05990+/-0.010, 1.15583+/-0.011, 1.22983+/-0.011 in cord blood DC groups. A value was 0.59517+/-0.005 in control group. The stimulating activities were higher in experimental groups than in control group (P<0.01), which were increased when the DC concentration was enlarged (P<0.01). Two differently derived DCs had the same phenotypes and similar stimulating activities (P<0.05). In peripheral blood DC groups, the cytotoxicity of the LD groups (experimental groups) and L groups (control group) was 58.16%+/-2.03% (5:1), 46.18%+/-2.25% (10:1) and 38.13%+/-1.29% (5:1) and 65.40%+/-1.56% (10:1) respectively; in cord blood DC groups, TD groups (experimental groups) and T groups (control groups) were 69.71%+/-2.33 % (5:1), 77.64%+/-1.94% (10:1) and 56.89%+/-1.82% (5:1) and 60.99%+/-1.42% (10:1) respectively.The cytotoxicity activities were enhanced with increased effector/target ratio (P<0.01). At the same effector/target ratio, the cytotoxicity of experimental groups were bigger than that of control groups (P<0.01). The cytotoxicity activities of cord blood DC groups were higher than that of peripheral blood DC groups (P<0.01). CONCLUSION: Peripheral blood DC and cord blood DC are mature DC in morphology and function, both can enhance the effector cell killing activities to hepatocarcinoma cells. DC pulsed with tumor antigen can induce higher specific CTL activity than unpulsed DC.

Antigen-Presenting Cells↗
PubMed2002

[Location of the probe dots in gene chip image with the medialness function].

For acquisition of the gene chip information, how to correctly locate the probe dots in the chip's scanning image is the base of the chip information processing. Here we present a new approach for locating the probe dots in the gene chip image. First, a medialness function, which is good at detection of circle area with radius given in advance, is used for calculating the medialness map in which the center of circle sample area of the gene chip image is disclosed prominently. Then, a method to locate the probe dots center is given based on the medialness map and the 2D space configuration of the probe dots. The experiments show that the new approach correctly locates the probe dots while against noise affection robustly.

Algorithms↗
PubMed2002

[The role of beta irradiation on neointimal formation and apoptosis in vein grafts model].

OBJECTIVE: To evaluate the effect of beta irradiation on intimal proliferation and apoptosis in vein grafts. METHODS: Autogenous vein graft model was established in 80 rats by transplanting the internal branch of the jugular vein to the carotid artery by end to end anastomosis. The veins were irradiated by (32)P solution before anastomosis. Two dose schedules were studied: control group (graft, nonirradiated) and radiation group (20 Gy). The grafted veins were harvested at 3, 1, 2 and 4 week respectively after the operation. intimal hyperplasia (IH), smooth muscle cell (SMC), proliferation, p53, bcl-2 and bax were observed pathologically and immunohistochemically. They were analyzed by a computerized system. The presence of apoptotic VSMC was demonstrated by TUNEL method. RESULT: There was a significant decrease in the average intimal thickness at 7, 14 and 28 days (t = 15.694, P < 0.05) in the radiation group. Immunohistochemical analysis of PCNA indicated decreased positive cells in the radiation group compared with the controls at 1 and 2 weeks (t = 60.157, P < 0.01). Apoptosis of VSMC was higher in the radiation group than in the control group at 2 weeks (t = 56.176, P < 0.01). There was no significant difference in expression of P(53) between the two groups, and there was a significant increase in bax/bcl-2 in the radiation group at 2 weeks (t = 9.783, P < 0.05). CONCLUSION: These preliminary results demonstrated that low dose of beta irradiation in the vein graft inhibits SMC proliferation and induces the apoptosis of VSMC in rats.

Animals↗
PubMed2002

Pharmacokinetics of leflunomide in Chinese healthy volunteers.

AIM: To study the pharmacokinetics of leflunomide in Chinese healthy volunteers. METHODS: A single (20, 40, and 60 mg) and 30-d -repeated (20 mg/d) oral doses of leflunomide were performed on 18 (12 males and 6 females) and 6 (4 males and 2 females) Chinese healthy volunteers respectively. A771726, the active metabolite of leflunomide, in serum was determined by high performance liquid chromatography (HPLC). Data were analyzed by a 3p97 program on a Legend computer. RESULTS: Serum concentration curves of A 771726 in single and repeated oral administration of leflunomide conformed to one compartment model of the first order absorption. Leflunomide was absorbed rapidly with T1/2,ka of between 1.15 h and 2.23 h in single oral administration. The major pharmacokinetic parameters of A771726 in 20, 40, and 60 mg groups were T1/2,ke(h): 211 +/- 18, 170 +/- 24, 252 +/- 26; Tmax(h): 13 +/- 12, 13 +/- 4, 9 +/- 5; Cmax (mg/L): 2.0 +/- 0.5, 5.2 +/- 0.6, 6.7 +/- 1.5; AUC (mg . h . L-1): 647 +/- 137, 1344 +/- 191, 2555 +/- 907, respectively. In repeated oral administration, steady stat e concentration was achieved within 30 d. The mean trough concentration was between 32.0 mg/L and 39.7 mg/L. The Cmax, Tmax, AU C0- 24 were (41.5 +/- 2.4) mg/L, (307 +/- 75) h, and (22099 +/- 1234) mg . h . L-1, respectively. CONCLUSION: The absorption of leflunomide was rapid, and it s elimination was slow after oral administration. The pharmacokinetic results showed that it exhibited first order kinetic characteristics.

Adult↗
PubMed2002

Effects of simulated microgravity on characteristics of photosynthesis in plant seedling.

OBJECTIVE: To study the effects of simulated microgravity on the characteristics of photosynthesis in some plant seedlings. METHOD: Plant samples were treated on a 1 pi clinostat rotated at 2 gamma/min for 120 h. Then chlorophyll absorption and chlorophyll fast fluorescence induction kinetics were determined. RESULT: After treatment on the clinostat: 1) there were some increase in height and number of leaves per plant; 2) the strawberry seedlings contained 47.5% less chlorophyll and the carnation seedlings contained 4.3% more; 3) there was no change in position of the main absorption peaks of chlorophyll in both seedlings after the rotation, but their intensity was increased; 4) there were significant increase in the parameters of fluorescence induction kinetics in the leaves of both seedlings: there was an increase in Fv/Fo, Fv/Fm and T1/2, except CA/Fo; 5) there were some differences in excitation energy distribution between the two photosystems in the chloroplasts of control and treated samples. CONCLUSION: Simulated microgravity does not have a significant effect on normal photosynthetic function in chloroplasts, so plant seedlings can grow up normally under microgravity.

Chlorophyll↗
PubMed2002

Modeling sorption isotherms of volatile organic chemical mixtures in model and natural solids.

Parameters from single-component isotherm models were used in multicomponent isotherm models to predict the aqueous phase sorption of trichloroethylene (TCE) in the presence of tetrachloroethylene (PCE) in four zeolites, Tenax, and three natural solids. The Langmuir, the Polanyi-Dubinin, and the Freundlich or the Langmuir-Freundlich isotherm models were used to simulate single-component sorption in zeolites. The Langmuir two-site, the Polanyi-Dubinin two-site, and the Freundlich or the Langmuir-Freundlich isotherm models were used to simulate single-component sorption in Tenax and natural solids. Two-site models have been used previously to model sorption in soils and sediments, and they combine an adsorption component (e.g., Langmuir) with a linear partitioning component. By using parameters from the different single-component isotherm models, the multicomponent Langmuir, the ideal adsorbed solution theory, and the Polanyi theory were each used to predict multicomponent sorption. In general, the ability to predict TCE sorption in the presence of PCE depended more on the choice of the single-component model than the multicomponent model, and better results were obtained when the Freundlich or the Langmuir-Freundlich isotherm was used for single-component sorption. This suggests that the more mechanistically based Langmuir and Polanyi-type models may not adequately describe the distribution of adsorption sites in some model and natural solids. The Freundlich or the Langmuir-Freundlich model, although empirical, has greater flexibility in characterizing sorbent heterogeneity and results in better multicomponent model predictions. However, this last statement is tenuous, because more solids must be tested against various model combinations.

Adsorption↗
PubMed2002

[Expression of IL-6 in recombinant non-replicating vaccinia virus and studying its effects on immunogenicity].

BACKGROUND: To investigate expression of IL-6 in non?replicating vaccinia virus and its immune effects on recombinant virus. METHODS: The recombinant non replicating vaccinia virus RVJ123 delta CK11 beta 75IL6 was constructed with non?replicating vaccinia virus vector pNEOCK11beta75IL6 and replicating vaccinia virus RVJ123. In animal model, immunization with the recombinant virus was carried out and its immune response was studied. RESULTS: The recombinant virus could express IL-nd HBsAg simultaneously. Southern blot analysis demonstrated that the genes between vaccinia virus Hind? C and K fragments were deleted and IL-6 gene was integrated stably. Given intranasal inocula of the virus to immunize BALB/c mouse and New Zealand Rabbit, the elevated anti-HBsAg IgA and IgG antibody secreting cells in mouse lung lymphoid to vectors expressing IL-6 was at about two?fold higher level than those elicited by control virus at day 14 after immunization. Authors also could detect elevated anti-HBsAg IgA and IgG antibody conversion in mouse serum and lung fluid, rabbits serum, lung fluid, saliva, vagina and nasal washing samples. CONCLUSIONS: IL-6 expressed by non-replicating recombinant vaccinia virus could enhance the induced?immune effects, it could serve as the effective adjuvant for recombinant vector vaccine.

Adjuvants, Immunologic↗
PubMed2002

[Intravertebral canals vascular malformations treated by superselective embolization].

OBJECTIVE: To assess the feasibility superselective embolization using microcatheters in treatment of intravertebral canal vascular malformation. METHODS: In 128 patients with intravertebral canals vascular malformation, their AVMS or fistulae were treated with silk thread, Ivalon microspheres or tungsten microcoils. RESULTS: In the 128 patients, 120 fistulae disappeared completely, but 8 were embolized 60% - 80%. Symptoms were improved in 113 patients. Improved muscular strength from grade I to IV was obtained in 8 patients, from grade II to III in 32, from grade III to IV in 32, and from grade IV to V in 41. The symptoms did not change in 15 patients. CONCLUSION: Superselective embolization through microcatheter is effective in the treatment of intraspinal canal vascular malformations.

Adolescent↗
PubMed2002

[Venous hypertensive myelopathy caused by narrowing of ascending lumbar vein].

OBJECTIVE: To assess the diagnosis and treatment of venous hypertensive myelopathy (VHM) caused by narrowing of the ascending lumbar vein. METHOD: The data from 3 patients with VHM caused by narrowing of the ascending lumbar vein were analyzed retrospectively. RESULTS: Once the narrowed site of the lumbar ascending vein was determined by myelographic or angiographic technique, an undetachable balloon was introduced and advanced to the proximal part of the narrowed segment. Satisfactory results were obtained in these patients. CONCLUSION: Narrowing of the ascending lumbar vein is one of the causes for VHM, and endovascular balloon angioplasty is an optimal treatment.

Aged↗
PubMed2002

[Cause of failure and false negative result in sentinel lymph node biopsy through vital blue injection in breast carcinoma].

OBJECTIVE: To investigate the cause of sentinel lymph node biopsy failure and false negative result in vital blue injection for breast cancer. METHODS: Eight-four female breast cancer patients were injected with vital blue to find the sentinel lymph nodes during operation. All patients were treated by the traditional radical or modified radical mastectomy with axillary dissection after sentinel node biopsy. All sentinel nodes, axillary lymph nodes and dissected specimens were submitted separately to pathological examination. RESULTS: Sentinel node was not identified at the time of operation in 11 patients, giving a failure rate of 13.1%. In 73 patients in whom sentinel nodes were identified, 32 (43.8%) revealed cancer invasion. Postoperative axillary node pathology showed cancer metastasis in all of them. Two patients who showed uninvaded sentinel nodes were demonstrated to have axillary node metastasis. These were the two false negative patients. Therefore, the prediction of axillary metastasis by the sentinel node biopsy showed a sensitivity of 90.4%, a specificity of 100% and a false negative rate of 2.7%. CONCLUSION: Failure in identifying the sentinel nodes in vital blue injection is related to the degree of mastering the technique and the method of injection. The cause of false negative result is due to an extensive primary tumor and the variation in the position of the sentinel lymph nodes.

Adult↗
PubMed2002

[Chemical constituents in volatile oil from the flos of Dendranthema indicum var. aromaticum var. nov].

OBJECTIVE: To analyse chemical constituents of volatile oil from Dendranthema indicum var. aromaticum var. nov. by GC-MS. METHOD: The volatile oil was extracted from Dendranthema indicum var. aromaticum var. nov. through steam distillation and was analysed with different kinds of capillary columns to find out the optimal conditions. The content of compositions of volatile oil was determined with normalization method, and the constituents were identified by GC-MS. RESULT: 44 Components were separated and identified, which accounted for over 43% of total volatile oil. CONCLUSION: The main constituents in the essential oils from Dendranthema indicum var. aromaticum var. nov. are Verberol, (-)zingiberene, beta-sesquiphellandrene, farnesene, transchrysanthenyl acetate, and caryophyllene.

Asteraceae↗
PubMed2002

[Studies on the chemical constituents from herba of Corallodiscus flabellata].

OBJECTIVE: To study the chemical constituents from Corallodiscus flabellata. METHOD: The compounds were isolated with macroporous adsorption resin, silica gel column chromatography and identified on the basis of their physiochemical and spectral data. RESULT: Six compounds were obtained and identified as vanillic acid, 3,4-dihydroxyphenylethyl-8-O-beta-D-glucopyranoside, syringic acid, caffeic acid, isoacteoside, ferulic acid. CONCLUSION: All the compounds were isolated from this plant for the first time.

Gallic Acid↗
PubMed2002

[Follow-up studies in polymyalgia rheumatica and temporal arteritis].

OBJECTIVE: To analyze the clinical course and duration of therapy in 28 patients with polymyalgia rheumatica (PMR) and/or temporal arteritis (TA) for identifying factors that influence prolonged steroid use and relapses. METHODS: 28 cases of PMR and/or TA diagnosed from 1992 to 2001 were retrospectively studied in PUMC hospital. Patients were grouped according to the absence or presence of corticosteroid resistant and relapses. RESULTS: Of 28 patients, 22 had pure PMR, 3 had both PMR and TA and 3 had pure TA. 15 patients received corticosteroid therapy and 13 had both corticosteroid and immunosuppressor therapy. The median duration was (25.5 +/- 24.0) months. Increase of white blood cell level and higher baseline erythrocyte sedimentation rate (ESR) were significant risk factors associated with corticosteroid resistant (P < 0.01). Quicker reduction of corticosteroid dose was associated with relapse (P < 0.05). CONCLUSIONS: Patients with increase of white blood cell level and higher baseline erythrocyte sedimentation rate (ESR) are more likely to be resistant to corticosteroid therapy. Quicker reduction in corticosteroid is more likely to relapse. Immunosuppressor therapy should be added to patients who has corticosteroid resistant, and relapse or PMR associated with TA.

Aged↗
PubMed2002

[Indirect determination of trace mercury ion by flame AAS].

In this paper, the method of indirect analysis of trace Hg2+ has been researched. In the HAc-NaAc buffer solution (pH = 5.0), copper can enrich and displace Hg2+ in solution of sample. The calibration curve of Hg2+ and Cu2+ is linear within in the range of 0-0.4 microgram.mL-1 of Hg2+. The trace mercury ion can be indirect determined by FAAS without separation. The recovery is 90%-110%, and the RSD is 3.5%. The method has been used for determining the trace Hg2+ in human hair with satisfactory results. The Hg2+ in solution is determined without any interference of common ions. Thus the method selection is excellent.

Hair↗