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Biomedical subjects

D Wu

Publications and source records attributed to D Wu.

At least 145 records · Page 8Linked to original sources
PubMed2000

Roles of phospholipid signaling in chemoattractant-induced responses.

Chemoattractants, including chemokines, play a central role in regulation of inflammatory reactions by attracting and activating leukocytes. These molecules have been found to regulate metabolism of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P(2)) via phospholipase C (PLC) and phosphoinositide 3-kinase (PI3K). Recent studies of mouse lines that lack PLC-(beta)2, PLC-(beta)3, or PI3K(gamma) demonstrate that chemoattractants act through PLC-(beta)2 and PLC-(beta)3 to hydrolyze PtdIns(4,5)P(2) and through PI3K(gamma) to phosphorylate PtdIns(4,5)P(2) in mouse neutrophils. These studies also confirmed the importance and revealed new roles of these signaling pathways in chemoattractant-induced responses.

Animals↗
PubMed2000

Chronic toxicity of rare-earth elements on human beings: implications of blood biochemical indices in REE-high regions, South Jiangxi.

Blood analyses for rare-earth element (REE)-high background regions in South Jiangxi show that the population averages of many of the biochemical indices deviate markedly from normal values in the normal region. These deviations are thought to be caused by prolonged intake of REE through food chains in view of that the toxicity of other harmful metals such as Pb and Cd can be neglected because of their insignificant amounts in the environment. In comparison with the normal region, blood biochemical indices abnormal in the REE-high regions are manifested as low total serum protein (TSP), albumin, beta-globulin, glutamic pyruvic transitanase, serium triglycerides, and immunoglobulin, but high cholesterol. These deviations may be related to the REE concentration and composition of food chains, and are sex dependent. Certain blood indices (such as TSP) of different age groups in the LREE-high region indicate that the influence of REE on males is a one-way irreversible process, whereas females show a strong ability of restoration.

Adult↗
PubMed2000

Rare-earth element distribution characteristics of biological chains in rare-earth element-high background regions and their implications.

The rare-earth element (REE) contents of water and vegetables from two typical REE-high background regions and a normal region in Gannan, Jiangxi Province, indicated that the REE contents were significantly different from those of water and vegetables, respectively. The average values are 0.03 mg/L and 0.11 mg/L REE for water from regions A and B. As the REE contents of vegetables from region A are different from region B, it is suggested that there are a number of factors controlling the REE distribution from those among plants. By comparing with the normal region, the soluble REE contents of water from the REE-high background regions are higher than those of the normal region by factors of 18 and 68, respectively. The REE contents of most plants and crops from regions A and B are higher than those of the normal region. It is clear that the REEs are the indispensable elements of plants during their growing period. Why are the REE contents of some plants from regions A and B usually higher than those from the normal region? The answer is that the plants and crops have passively absorbed REE during their growth.

China↗
PubMed2000

[Cytogenetics and clinical studies of hematologic malignancies with 11q23 abnormalities in China].

OBJECTIVE: To evaluate the association between 11q23 abnormalities and the clinical, hematologic, prognostic aspects of hematologic malignancies. METHODS: A total of 6000 cases of hematologic malignancies from our hospital and near regions in China were investigated between October 1985 and November 1998. Chromosome preparations were made on bone marrow cells by using direct method and/or unstimulated short-term cultures. Karyotypes were analyzed by R-banding technique and expressed according to ISCN(1995). RESULTS: 11q23 abnormalities were found in 28 of 6000 cases with hematologic malignancies(0.47%). It may be separated into seven cytonetic categories: t(4;11)(q21;q23)(ten cases), t(11;19)(q23;p13)(five cases), t(9;11)(p12;q23)(two cases), t(10;11)(p15;q23)(two cases), t(6;11)(q27;q23) (one case), del(11)(q23)(seven cases), and t(11;?)(q23;?)(one case). The diagnoses included acute myeloid leukemia in 14 cases (M(2a), three; M(4), two; M(5a), one; M(5b), eight), acute lymphoblastic leukemia(ALL) in 10 cases, myelodysplastic syndrome in three cases and malignant histiocytosis in one case. All 10 cases with t(4;11) anomaly were ALL. Follow-up data were available for 22 of them. Their median survival was 113 days. The patients may be grouped according to the presence or absence of additional abnormalities and/or normal karyotype. The median survival was 75 days for five patients with 11q23 anomaly only, 18 days for two patients with 11q23 and additional abnormalities, 135 days for 10 patients with 11q23 anomaly, additional abnormalities and normal karyotype, and 150 days for 5 patients with 11q23 anomaly and normal karyotype. CONCLUSION: 11q23 abnormalities were mainly seen in ALL and acute monocytic leukemia. Their prognosis was very poor. Both additional abnormalities and lack of normal karyotype had adverse effects on the survival of patients. Thus, they represent a unique clinical-cytogenetic association. 11q23 abnormality; hematologic malignancy; acute monocytic leukemia; acute lymphoblastic leukemia; prognosis

Adolescent↗
PubMed2000

Impaired protein synthesis induced by acute alcohol intoxication is associated with changes in eIF4E in muscle and eIF2B in liver.

BACKGROUND: Acute alcohol intoxication in rats decreases protein synthesis in skeletal muscle and, to a lesser extent, in liver. The purpose of the present study was to examine potential mechanisms for the inhibitory effect of acute ethanol exposure. METHODS: Rats were injected intraperitoneally with either ethanol (75 mmol/kg) or saline, and tissues were examined 2.5 hr later. Rates of protein synthesis in vivo were determined by [3H]phenylalanine incorporation into protein, and various eukaryotic initiation factors (eIFs) were quantitated by Western blot analysis to identify possible mechanisms for regulating translation. RESULTS: Protein synthesis in gastrocnemius and liver was decreased (39% and 21%, respectively) after alcohol administration, compared with saline-injected control animals. Alcohol administration did not alter tissue RNA content but diminished translational efficiency in muscle (43%) and liver (24%). Hepatic eIF2B activity was decreased 24% in alcohol-treated rats, and this was associated with a 95% increase in eIF2alpha phosphorylation. However, alcohol did not alter the amount of 4E-binding protein 1 (4E-BP1) bound to eIF4E, cIF4E bound to eIF4G, or the phosphorylation state of either 4E-BP1 or eIF4E. In contrast to liver, neither eIF2B activity nor the phosphorylation of eIF2alpha was affected in muscle of alcohol-treated rats. However, acute alcohol intoxication increased binding of 4E-BP1 to eIF4E (113%), decreased the amount of cIF4E bound to cIF4G (81%), and decreased the amount of 4E-BP1 in the phosphorylated gamma-form (77%). The plasma concentrations of insulin and insulin-like growth factor-I were unchanged by alcohol, but muscle insulin-like growth factor-I messenger ribonucleic acid abundance was decreased 35%. CONCLUSIONS: These data suggest that acute alcohol intoxication decreases translation initiation and protein synthesis in liver and muscle via different mechanisms. Changes in eIF2B appear to predominate in liver, whereas alterations in eIF4E availability appear more critical in skeletal muscle for controlling translation initiation.

Alcoholic Intoxication↗
PubMed2000

Regional analysis of divorce in China since 1980.

This paper estimates and discusses divorce measures in China and its 30 provinces since 1980. The propensity for divorce in China increased 42% between 1982 and 1990. Substantial increases in divorce were observed in all provinces except Xinjiang and Shanxi. We found a fairly strong regional pattern of divorce in China: Divorce rates were lowest on the east coast and in eastern areas, highest in the northwest and the northeast, and moderate in the middle and southern parts of the country. Descriptive explanations of trends and regional variations are presented.

China↗
PubMed2000

Simulation of body surface Laplacian maps during ventricular pacing in a 3D inhomogeneous heart-torso model.

A computer simulation study has been conducted to investigate the performance of body surface Laplacian maps (BSLMs) in localizing and imaging spatially separated myocardial electrical events. A cellular automaton model of ventricles simulates cardiac electrical activity using a two-site pacing protocol to induce dual simultaneously active myocardial electrical events. The heart model is embedded in a realistically shaped inhomogeneous volume conductor. The BSLMs are numerically computed from the induced electrical activity in the heart model. The present computer simulation results show that the BSLM can provide better separation and localization of two regional myocardial electrical events as compared with the body surface potential map (BSPM).

Artifacts↗
PubMed2000

Cytotoxic effects of 5-fluorocytosine on melanoma cells transduced with cytosine deaminase gene.

To investigate the cytotoxic effects of 5-fluorocytosine on melanoma cells genetically modified with cytosine deaminase gene, the gene was transduced into the tumor cells with the retroviral method. The cytotoxicity effects of 5-fluorocytosine on the tumor cells were measured with the MTT assay and clonogenic assay. It was found that the prodrug 5-fluorocytosine had significant cytotoxic effects on melanoma cells transduced with cytosine deaminase in vitro. The IC50 value of 5-fluorocytosine on transgenic and nontransgenic melanoma cells was 572 microg/mL(-1) and 3870 microg/mL(-1), respectively. Our experiment demonstrated the potential value of the cytosine deaminase gene/5-fluorocytosine system in the treatment of melanoma.

3T3 Cells↗
PubMed2000

Potentiation of BCNU anticancer activity by O6-benzylguanine: a study in vitro and in vivo.

O6-Alkylguanine-DNA alkyltransferase (O6-AGT), a constitutively expressed DNA repair protein, removes alkyl groups from the O6-position of guanine in DNA. Tumor cells with high O6-AGT activity are resistant to nitrosoureas and other agents that form toxic O6-alkyl adducts. We evaluated O6-benzylguanine (O6-BG) for its activity to inhibit O6-AGT and potentiate 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) in O6-AGT-positive human gastric adenocarcinoma cell line, BGC-823 and its tumor xenograft. The sensitivity of BGC-823 cells to BCNU was increased by pretreatment for 2 hours with 1.5 to 6.0 microg/mL O6-benzylguanine. O6-benzylguanine (0.75-6.0 microg/mL) completely and rapidly suppressed the O6-AGT activity of cells for up to 12 hours. When given i.p. 2 hours before BCNU (25 mg/kg) to animals bearing s.c. tumors, O6-BG (90 mg/kg) produced a growth delay of 38.6 days in human gastric adenocarcinoma xenograft. Furthermore, O6-BG significantly inhibited the O6-AGT activity of tumor tissue and induced evident apoptosis. These results suggest that combination of O6-BG with BCNU may have a significant therapeutic effect in the treatment of mer + tumor.

Alkyl and Aryl Transferases↗
PubMed2000

Therapeutic drug monitoring of paclitaxel (Zisu) in cancer patients.

We monitored the therapeutic drug paclitaxel (Zisu) and studied its anticancer activity and side effects in 11 cancer patients. After intravenous infusion of 135 to 185 mg/m2 of paclitaxel, Cmax ranged from 2.17 to 9.17 mg/L and AUC ranged from 4.37 to 16.01 mg/h/L. A significant individual difference in pharmacokinetic parameters was found. Among the 11 patients, 6 achieved a partial remission and one patient had a mild response. The Cmax of the patients who achieved PR and MR was higher in comparison to the patients with no response. In 4 of the 6 PR patients, Cmax was above 4.38 mg/L. In four of the NR patients, Cmax was equal to or below 4.04 mg/L. These results suggested a relationship between Cmax and the cancer response rate. No significant relationship could be found between Cmax and the nadir of the white blood cells and platelets.

Adult↗
PubMed2000

Potentiation of docetaxel antitumor activity by batimastat against mouse forestomach carcinoma.

Docetaxel is a chemical compound belonging to the taxoid class of anticancer agents. Batimastat (BB-94) is the first matrix metalloproteinase inhibitor entering clinical trials. To improve the treatment of tumors, we studied the combined effects of docetaxel and batimastat on mouse forestomach carcinoma (MFC), and compared them with doxorubicin. In vitro growth curve analysis, MTT assay, and clonogenic assay were used to determine the cytotoxic effect of docetaxel or/and BB-94 on MFC. They showed that docetaxel, but not BB-94, had a significant cytotoxicity and that the effect of docetaxel was not enhanced by BB-94. In an early stage MFC tumor model, an obvious antitumor effect of docetaxel or doxorubicin given iv at maximum tolerated dose (MTD) was observed. Tumor growth inhibition was greater for docetaxel + BB-94 (96.0%) than for doxorubicin + BB-94 (88.0%), docetaxel (89.0%), doxorubicin (68.0%), and BB-94 (33.0%). Docetaxel showed activity against advanced stage MFC tumor in a dose-dependent manner and was more effective at MTD than doxorubicin, with 4/5 regression, 46.5 days tumor growth delay, and 2.8 log10 tumor-cell kill. Our results suggest that docetaxel is an effective new cytotoxic drug against MFC tumor and that BB-94 enhances the antitumor activity of docetaxel in the dose and schedule used.

Animals↗
PubMed2000

[Preparation of biological bone carrier].

A series of studies on biological bone carrier (BBC), including preparation methods, components analysis, animal implantation test, biomechanical strength, ultrastructure, cross antigenicity and clinical application are reported in this article. Comprehensive process was adopted to reduce the antigen of BBC. As a substitute for bone, BBC has the following merits: (1) good biocompatibility; (2) suitable mechanical strength; (3) natural porous structure and porosity; (4) absorbability and replaceability in host; (5) unlimited sources, ready availability and simplicity in process and storage; (6) both functions of osteoconductability and osteoinductability can be developed after BBC combined with BMP.

Animals↗
PubMed2000

[Studies on the mechanisms of developmental toxicity of alcohol].

OBJECTIVE: To study the mechanisms of developmental toxicity in animals induced by ethyl alcohol. METHOD: Rat embryos of 9.5 days of gestation were exposed to different doses of ethyl alcohol in vitro. Postimplantation whole embryo culture and fluorescence polarization technique were used to investigate the effects of alcohol on embryo development and visceral yolk sac (VYS) membrane lipid fluidity. RESULT: 400 mg alcoho/L caused no significant differences to embryo development, organ morphological scores, polarization (Pr value) and lipid fluidity unit (LFU), as compared with the non-alcohol treated controls. 1,000 mg alcohol/L led to the decrease of scores of brain, VYS circle, neurotube, head length and heart, as well as DNA and Pr value; whereas LFU values were increased significantly. Above 2,000 mg alcohol/L, all indexes were decreased except LFU of VYS cell membrane. Alcohol significantly elevated lipid fluidity of VYS cell membrane. CONCLUSIONS: Alcohol causes development toxicity and teratogenisis in rats. Brain and VYS are the targets of alcohol effect. Its development toxicity is related with lipid fluidity and the VYS membrane damage.

Abnormalities, Multiple↗
PubMed2000

Benefits of late coronary artery stenting in patients with acute myocardial infarction with and without thrombolytic therapy.

BACKGROUND: There are no added benefits when balloon angioplasty is conducted in conjunction with thrombolytic therapy in patients with acute myocardial infarction. The purpose of this study was to determine whether or not thrombolysis has an impact on the outcome of late coronary artery stenting following acute myocardial infarction. METHODS: The outcome of late coronary artery stenting in the infarct-related artery following acute infarction was compared in patients with (68 patients, group A) and without (118 patients, group B) prior thrombolytic therapy. RESULTS: The baseline characteristics were similar in the 2 groups except that total occlusion of the infarct-related artery was more common in group B. The angiographic characteristics of the target lesion were similar in the 2 groups; the procedural success rate was 98% in both groups. There was no subacute thrombosis or other complications in either group. The 6-month follow-up coronary angiography and the restenosis rate was 18% in both groups; the reocclusion rate was 2% in group A and 4% in group B. The increment of the left ventricular ejection fraction was similar in both groups (6% versus 7%). During a follow-up duration of 18 +/- 3 months, the mortality rate was 3% versus 2%, reinfarction 0% versus 1%, recurrent angina 6% versus 4%, and target lesion revascularization by angioplasty 13% versus 13% in group A and B patients, respectively. CONCLUSION: The outcome of late coronary artery stenting following acute myocardial infarction in patients with and without prior thrombolytic therapy was comparable. Significant improvement of left ventricular function was noted in both groups.

Adult↗
PubMed2000

Inhibition of calcium signaling in terminal and soma of carp retinal bipolar cells by GABA.

AIM: To investigate the effect of activation of gamma-aminobutyric acid (GABA) receptors on high K(+)-evoked Ca2+ signaling in the terminal and soma of carp retinal ON-type bipolar cells. METHODS: Freshly dissociated carp retinal cells were loaded with fluo-3AM and then the fluorescence measurements were performed on a confocal laser-scanning microscope. RESULTS: Ca2+ signaling evoked by high K+ 35 mmol/L was completely suppressed in both the terminal and soma of bipolar cells by GABA 100 mumol/L. However, different results were found in the terminal and soma when only one subtype of GABA receptors was activated. While activation of either GABAA or GABAC receptors totally suppressed Ca2+ signaling in the soma, a gradual elevation of [Ca2+]i appeared in the terminal. GABA 10 mumol/L could also completely suppress Ca2+ signaling in the soma, but could only partially reduce Ca2+ signaling in the terminal. CONCLUSION: Activation of both GABAA and GABAC receptors could completely inhibit high K(+)-evoked Ca2+ signaling in the terminal and soma of carp retinal ON-type bipolar cells. While activation of either GABAA or GABAC receptors alone still totally suppressed Ca2+ signaling in the soma, a gradual elevation of [Ca2+]i appeared in the terminal, which may be due to desensitization of GABA receptors.

Animals↗
PubMed2000

[Effect of elevated CO2 concentration on photosynthesis and antioxidative enzyme activities of wheat plant grown under drought condition].

The photosynthesis and antioxidative enzyme activities of wheat plants grown in two open-top chambers with CO2 concentrations of 350 mumol.mol-1 and 700 mumol.mol-1 were examined under drought stress. The result showed that elevated CO2 concentration obviously enhanced the photosynthesis, stomatal resistance and water use efficiency, but decreased the transpiration of wheat. Doubled CO2 concentration significantly increased the activities of CAT, POD and SOD, which enhanced the abilities of antioxidative defence and drought tolerance.

Carbon Dioxide↗
PubMed2000

[Structure and spatial pattern dynamics of dominant populations in a natural forest in north Guangdong Province].

Five 1000-m2 plots were set up in a forest dominated by Schima superba, Castanopsis fargesii and Pinus massoniana in Luoba Nature Reserve, Shixing County, north Guangdong Province. Field data were obtained by tally with contiguous grid quadrat method. The analysis of population structure and spatial distribution patterns of the dominant species in the forest shows that S. superba and C. fargesii had a large reserve of seedlings, with up to 1538 and 9763 seedlings per hm2, respectively, showing a pyramid shape of population structure. Both populations had a high mortality for seedlings of classes I and II in the process of development to saplings. The population structure of P. massoniana was an inverse pyramid type, with no seedlings and only 4 saplings per hm2, but 44 large trees per hm2. The spatial distribution patterns of P. massoniana and C. fargesii in coniferous broadleaved mixed community chiefly dominated by broadleaved trees were uniform, and in those chiefly dominated by P. massoniana were aggregated, but there were different causes of pattern dynamics for P. massoniana and C. fargesii. S. superba in both communities showed an aggregated distribution pattern. The aggregation intensity was different, with K values from 0.4280 to 0.9750. Regarding the distribution patterns in different development stages, S. superba was aggregated in different stages, while C. fargesii varied with uniform distribution pattern for the large trees and aggregated distribution pattern for the saplings and median trees. As for P. massoniana, its median trees showed an aggregated distribution pattern, while both the saplings and large trees were uniform. The variations in spatial distribution patterns of populations in different development stages were closely related to the biological and ecological characteristics of the species, but different block size had an impact on the outcome of spatial distribution patterns.

China↗