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B Q Wu

Publications and source records attributed to B Q Wu.

At least 19 recordsLinked to original sources
PubMed1996

11-Oxo-tetrodotoxin and a specifically labelled 3H-tetrodotoxin.

Tetrodotoxin was oxidized to a hydrated aldehyde, 11-oxo-tetrodotoxin, which shares the specificity of tetrodotoxin for the Na+ channel of the isolated voltage-clamped frog skeletal muscle fiber, but is four to five times more potent. It binds to the solubilized Na+ channel of eel electroplax with a similarly higher potency, because of an equilibrium dissociation constant about 0.25, and a dissociation rate constant 2.4 times slower than those for tetrodotoxin. 11-Oxo-tetrodotoxin can be reduced to regenerate a tetrodotoxin, which is chemically and biologically indistinguishable from the original tetrodotoxin. By reducing with tritiated sodium borohydride, a 3H marker can be inserted regiospecifically to yield 11-[3H]-tetrodotoxin. Because it has a defined specific activity of > 2.5 Ci/mmole, and a 3H marker which does not exchange with solvent proton, 11-[3H]-tetrodotoxin is an ideal tracer for tetrodotoxin. It may enable studies of problems which require higher signals and/or better stability of the marker than those obtainable from currently available tracer Na(+)-channel ligands.

Animals↗
PubMed1994

[The expression of 67-KD laminin receptor (LN-R) gene in PG tumor cells with high metastatic potential].

The expression level of 67-KD LN-R mRNA was observed in high-metastatic PG tumor cells and low-metastatic PAa tumor cells based on the cDNA fragments of 67-KD LN-R amplified by PCR technique and the specific cDNA probe prepared by random primer labeling method. Results showed that the transcripts were homologous in size, about 1.7kb, in PG and PAa tumor cells. The 67-KD LN-R mRNA level was higher in PG than that in PAa tumor cells, and gene amplification was also more marked in PG tumor cells. After treated with 67-KD LN-R monoclonioal antibody (50, 100 and 400 micrograms/ml) for 48 hours, LN-R mRNA of PG tumor cells decreased significantly. It is suggested that 67-KD LN-R may play important roles in metastatic processes of PG tumor cells.

Base Sequence↗
PubMed1994

[Effects of metalloproteinases-1 (TIMP-1) cDNA transfection on biological behaviors of PG cells].

A recombinant plasmid, which contains a full length cDNA of human tissue inhibitor of metalloproteinases-1 (TIMP-1), was constructed by using gene recombinant technique, and introduced into a highly metastatic human giant cell carcinoma (PG) by lipofectin technique. Two of the transfectants, PG-T2 and PG-T4, were studied thoroughly. Northern blot showed an increased level of TIMP-1 mRNA in PG-T2 and PG-T4, compared with PG and PG-MV1 (vector-transfected control). The two transfectants also exhibited higher TIMP-1 protein activities. Moreover, they showed significant reduction in their proliferation rate and invasive abilities. The abilities of forming colonies in soft agar and tumorigenecity in athymic nude mice were abrogated in PG-T2 and PG-T4. The preliminary results suggest that a specific upregulation of TIMP-1 expression in metastatic cells could not only suppress their invasive and metastatic phenotype, but also inhibit their proliferation and tumorigenecity.

Animals↗
PubMed1993

Differential growth regulation of a metastatic human lung carcinoma cell line through activation of phosphatidyl inositol turnover signal transduction pathway.

Until recently, the signal transduction pathways involved in the processes of tumor growth have been poorly understood. In the present study, we investigated cell surface receptors which utilize phosphatidylinositol (Pl) turnover/Ca2+ mobilization as a signal transduction pathway to regulate cell growth in a metastatic human lung carcinoma cell line, PG. We found that purinoceptor agonists, including ATP and its analogs, and bombesin, an amphibian tetradeca-peptide of mammalian homology gastrin-releasing peptide, induced rapid transient increase of cytoplasmic-free Ca2+ in PG cells loaded with fura-2. The Ca2+ responses were derived both from release from internal stores and the opening of plasma membrane Ca2+ channels. HPLC analysis of inositol 1,4,5-triphosphate (Ins(1,4,5)P3) and its isomers showed a receptor-linked phospholipase C activation by ATP and bombesin. Although ATP and bombesin were both able to induce Pl turnover and Ca2+ mobilization in PG cells, they had differential growth regulatory effects on PG cells. Treatment with bombesin stimulated PG cell growth while treatment with ATP inhibited significantly PG cell growth. Pharmacological studies showed that the purinoceptors on PG cells were of the P2 subtype. Other hydrolysis-resistant P2 purinoceptor agonists, including ATP gamma S and AMP-PNP, were as effective as ATP in stimulating Pl turnover and Ca2+ mobilization as well as in inhibiting PG cell growth in vitro, suggesting the potential usefulness of such ATP analogs in clinical trials. Preliminary results suggest G protein involvement in the differential regulation of ATP and bombesin signal transduction pathways.

Adenosine Triphosphate↗
PubMed1993

Patterns of spatial dispersion, locomotion and foraging behaviour in three groups of the Yunnan snub-nosed langur (Rhinopithecus bieti).

Aspects of the behaviour of three groups of Yunnan snub-nosed langurs, Rhinopithecus bieti, were observed over the course of three field seasons from 1986 to 1988. The major findings of the study were: (1) The habitats of R. bieti were mainly at heights of 3,600-4,150 m above sea level. (2) Groups were very large, with group sizes ranging from more than 100 to 269 individuals. (3) Spatial dispersion densities ranged from about 27 to 106 m2/individual during sleeping and resting, to feeding dispersions as large as 5,000-15,000 m2. (4) The locomotor repertoire of R. bieti consisted largely of walking, jumping and climbing. On very rare occasions, semibrachiation was observed, but true brachiation was never observed. The locomotor repertoires of juveniles were more diverse than those of subadults or adults. (5) Communication consisted mainly of eye-to-eye contact accompanied by murmurs; while loud calls were heard only rarely. (6) Groups moved between sleeping and feeding sites in single file. It is concluded that R. bieti is a mainly terrestrial species.

Aging↗
PubMed1993

[Signal transduction study on the growth regulation of cells from human giant cell lung carcinoma in vitro].

The signal transduction involved in growth regulation of cells originally from a human giant cell lung carcinoma(PG) was investigated. The purinergic receptor agonists, ATP and its analogues, as well as bombesin all played a significant growth regulatory role on PG cells. ATP showed a growth inhibitory effect while bombesin showed a growth stimulatory effect on PG cells in vitro. Further investigation showed that ATP and bombesin activated phosphatidylinositol turnover/calcium mobilization signal transduction pathways in PG cells. and increased production of inositol-(1,4,5) trisphosphate and mobilization of intracellular free calcium, in which ATP and bombesin effects were dose-dependent. The purinergic receptor on PG cells was characterized by P2y subtype according to the order of PG cell responses to a series of ATP analogues. Pretreatment with cholera toxin showed different effects on the functions of ATP and bombesin, suggesting that the major difference between ATP and bombesin on signal transduction pathways may be at the G protein level.

Adenosine Triphosphate↗
PubMed1989

[Cerebral infarction in 141 cases treated by traditional Chinese medicine and Western medicine].

Acute cerebral infarction of 141 cases with treatment combining TCM and WM was reported. The significant effective rate and the effective rate were 65% and 84% in the LT group (low molecular dextran + TCM) respectively; in the LN group (low molecular dextran + Nicotinic acid) were 29% and 41% respectively; in the T group (Salvia miltiorrhiza + Astragalus + Puraria) were 40% and 81.8% respectively. Among them the therapeutic effect in the LT group was the best. The LT group was also superior to the other two groups in serious cases. Cerebral edema developed following cerebrovascular dilator in a week after cerebral infarction; in the early stage, the therapeutic effect could be improved by giving mannitol first and then cerebrovascular dilator. Heart failure could be easily induced by low molecular dextran in the cerebral infarction following rheumatic heart disease. The therapeutic effect was poor in those cases with recurrent cerebral infarction.

Adult↗
PubMed1989

Comparative study of metastatic behavior of a human tumor cell line in athymic (nu/nu) and beige nude mice (bg/bg-nu/nu).

In this experiment, the "nu" gene was introduced into "beige" mutant mice, which are immunodeficient in NK cell activity. The resultant beige nude mice (bg/bg-nu/nu) have combined immunodeficiency in both T and NK cell activities. The level of NK cell activity in beige nude mice is slightly higher than that in beige mice, but much lower than that in nude mice. This is consistent with other studies. In order to elucidate the role of the metastatic behavior of a human tumor cell line PAa in both athymic nude mice and beige nude mice. The PAa cell line was originally established from a human lung adenocarcinoma and maintained as a solid tumor by serial s.c. passage in nude mice. During the first 18 passages in nude mice, PAa cells were found to have metastasized spontaneously to regional lymph nodes in only 4 animals, but metastases were no longer found in subsequent passages. The total incidence of metastasis in nude mice was 9% (4/44). However, when inoculated s.c. into beige nude mice, the metastatic rate of PAa cells was 43% (9/21) to the regional lymph nodes and 10% (2/21) to the lungs in two separate experiments. We conclude from the results that NK cells may play an important, if not exclusive, role in host resistance to tumor metastasis. Beige nude mice could serve as a useful in vivo model in studies of the biology and heterogeneity of human tumor metastasis.

Adenocarcinoma↗
PubMed1988

[In vivo metastasis of human tumor transplant in T and NK cell immune-deficient mice].

Beige-nude mice with combined T and NK cell deficiency were produced by introducing "nu" gene into the beige mice of C57BL/6 background. The beige-nude mice were characterized by morphological features, level and activity of the NK cell in spleen and peripheral blood. NK cell level of the beige-nude mice was higher than the beige mice and similar to the ordinary nude mice though its NK cell activity was markedly lower than the nude mice. Human lung adenocarcinoma (PAa) was transplanted subcutaneously to the beige-nude mice and nude mice of BALB/cA background. No metastasis was found in BALB/cA nude mice (0/7), while in beige-nude mice, spontaneous lymph node metastasis rate was 36.3% (4/11). It should be noted that the transplanted PAa metastasized to lungs, which had never been seen in BALB/cA nude mice in previous experiments. The increase of metastatic rate is correlated with the relative low NK cell activity of the beige-nude mice. Our observation is that the beige-nude mice could be a suitable experimental model for in vivo study on metastatic behavior of the human tumors.

Adenocarcinoma↗
PubMed1985

[Establishment of highly metastatic human tumor cell line in nude mice].

A total of 22 adult nude mice (7 approximately 17 weeks old) of BALB/cA origin were inoculated subcutaneously (SC) with human tumor cell lines derived from rhabdomyosarcoma and lung carcinomas, including squamous cell carcinoma, bronchiolo-alveolar carcinoma, small cell carcinoma, giant cell carcinoma and 2 types of adenocarcinoma. 12 neoplasms (54.5%) was confirmed at the initial transplantation and 7 serially transplantable tumors were established in 201 nude mice. Metastatic behavior of 7 human tumor cell lines grown in nude mice was judged histologically after sacrifice and SC transplanted tumors could either be highly metastatic (giant cell carcinoma), moderately metastatic (adenocarcinoma PAb), poorly metastatic (squamous cell carcinoma and adenocarcinoma PAa) or non-metastatic (small cell carcinoma and bronchiolo-alveolar carcinoma). The tumor from SC inoculated giant cell carcinoma (PG) could produce regional and/or distant lymph node metastases (12/12) and lung metastases (9/12) in BALB/cA nude mice maintained under semi-barrier system conditions. Six NIH nude mice developed metastatic tumor nodules both in the lymph node and lung (6/6) under the same condition. The highly metastasizing property of PG transplanted tumors remained after passage for as many as 18 times. The limitations of nude mice as an in vivo model for the study of tumor biology are discussed, eg. malignant neoplasms rarely metastasize when transplanted into nude mice. The use of such model (PG) could lead to a better understanding of the biology of metastasis, thus contributing to the development of new approaches to the therapy of metastasis.

Adenocarcinoma↗
PubMedDate not supplied

Association of EGFR gene fragments with nuclear matrix proteins in high and low metastatic melanoma cell lines.

Two melanoma cell lines with different metastatic potential were used to study the association of EGFR gene fragments with the nuclear matrix and its role in cancer metastasis by polymerase chain reaction. A 940 bp positive amplification by PCR using primers I-II was demonstrated in a high metastatic cell line, WM451. A 110 bp positive amplification was shown using primers III-IV in both high and low metastatic cell lines. This finding demonstrates that EGFR gene fragments are tightly bound to the nuclear matrix and suggests that binding ability of this EGFR gene fragment to nuclear matrix seems to be closely related to metastatic potential in melanoma cell lines WM45 1 and WM35.

Antigens, Nuclear↗
PubMedDate not supplied

Expression of laminin in metastatic melanoma cell lines with different metastatic potential.

Cancer metastasis is a complex multi-step process in which tumor cells leave the primary site and develop a secondary tumor in distant organs. Laminin plays an important role in this process. The expression of laminin in four melanoma cell lines with different metastatic potentials was investigated by immunohistochemistry, immunogold electron microscopy and Western blotting. Our results showed that the expression of endogenous laminin and the percentage of the positive cells are higher with increased metastatic potentials. It is, thus, suggested that endogenous laminin may contribute to the different metastatic properties in the melanoma cell line.

Blotting, Western↗