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Bing Liu

Publications and source records attributed to Bing Liu.

At least 37 records · Page 2Linked to original sources
PubMed2006

A role for voltage-gated, but not Ca2+-activated, K+ channels in regulating spontaneous contractile activity in myometrium from virgin and pregnant rats.

The roles of voltage-gated (K(V)) and large conductance Ca2+-activated K+ (BK(Ca)) channels in regulating basal contractility in myometrial smooth muscle are unresolved. The aim of this study was to determine the effects of inhibition of these channels on spontaneous rhythmic contraction in myometrial strips from four groups of rats: nonpregnant and during early (day 7), mid- (day 14), and late (day 21) pregnancy. BK(Ca) channels were inhibited using iberiotoxin (1-100 nM), paxilline (1-10 microM) or penitrem A (1-500, or 3000 nM); K(V) channels were inhibited using tetraethylammonium (TEA; 1-10 mM) and/or 4-aminopyridine (4-AP; 1-5 mM). Contractility was assessed as mean integral tension (MIT). Time/vehicle controls were also performed. None of the selective BK(Ca) channel inhibitors significantly affected contractility in myometrial strips from either nonpregnant or pregnant animals. 4-AP caused concentration-dependent increases in MIT in myometrium in all four groups. TEA (5 and 10 mM) significantly increased MIT in myometrium from nonpregnant, and mid- and late pregnant rats, but not in myometrium from early pregnant rats. TEA and 4-AP still caused an increase in MIT following treatment with 3000 nM penitrem A or a combination of propranolol, phentolamine, atropine (all 1 microM) and capsaicin (10 microM) in myometrial strips from nonpregnant rats. These results indicate that whereas BK(Ca) channels play little or no part in controlling basal rhythmicity in rat myometrium, K(V) channels appear to play a crucial role in this regard, especially during mid- and late pregnancy.

Animals↗
PubMed2006

An efficient semi-unsupervised gene selection method via spectral biclustering.

Gene selection is an important issue in microarray data processing. In this paper, we propose an efficient method for selecting relevant genes. First, we use spectral biclustering to obtain the best two eigenvectors for class partition. Then gene combinations are selected based on the similarity between the genes and the best eigenvectors. We demonstrate our semi-unsupervised gene selection method using two microarray cancer data sets, i.e., the lymphoma and the liver cancer data sets, where our method is able to identify a single gene or a two-gene combinations which can lead to predictions with very high accuracy.

Artificial Intelligence↗
PubMed2006

Opposing effects of arsenic trioxide on hepatocellular carcinomas in mice.

Arsenic trioxide (As2O3) is a potent antitumor agent used to treat acute promyelocytic leukemia (APL) and, more recently, solid tumors. However, the dose of As2O3 required to suppress human xenographs in mice is markedly higher than that used to treat APL in humans. Paradoxically, low doses of As2O3 stimulate angiogenesis, which might be expected to promote tumor growth. Clearly, appropriate dosages of As2O3 are required to treat human patients to avoid toxicity and undesirable side effects. In the present study, we investigated As2O3 with respect to its toxicity and effects on tumor growth, angiogenesis and cell apoptosis using H22 hepatocellular carcinoma (HCC) cells in a mouse model of HCC. As2O3 inhibited tumor growth and angiogenesis, and enhanced tumor cell apoptosis at doses greater than 1 mg/kg, but mice lost weight and failed to thrive at doses of 4 mg/kg and greater. In contrast, low doses (<1 mg/kg) of As2O3 promoted tumor growth, upregulated the expression of vascular endothelial growth factor and tumor angiogenesis, and had no effect on tumor cell apoptosis. In vitro studies demonstrated that As2O3 inhibited the proliferation of H22 tumor cells and bovine aortic endothelial cells, and induced their apoptosis in a dose- and time-dependent fashion, suggesting that the mechanism of As2O3-mediated inhibition of tumor growth is due to direct effects of the drug on both tumor cells and endothelia. In summary, different doses of As2O3 have opposing effects on tumor growth and angiogenesis. The results demonstrate that As2O3 has a narrow window of therapeutic opportunity with respect to dosage, and that low doses of the drug as used in metronomic therapy should be used with extreme caution.

Animals↗
PubMed2006

Alleviation of pre-exposure of mouse brain with low-dose 12C6+ ion or 60Co gamma-ray on male reproductive endocrine damages induced by subsequent high-dose irradiation.

Irradiation has been widely reported to damage organisms by attacking on proteins, nucleic acid and lipids in cells. However, radiation hormesis after low-dose irradiation has become the focus of research in radiobiology in recent years. To investigate the effects of pre-exposure of mouse brain with low-dose (12)C6+ ion or 60Co gamma (gamma)-ray on male reproductive endocrine capacity induced by subsequent high-dose irradiation, the brains of the B6C3F1 hybrid strain male mice were irradiated with 0.05 Gy of (12)C6+ ion or 60Co gamma-ray as the pre-exposure dose, and were then irradiated with 2 Gy as challenging irradiation dose at 4 h after pre-exposure. Serum pituitary gonadotropin hormones, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), testosterone, testis weight, sperm count and shape were measured on the 35th day after irradiation. The results showed that there was a significant reduction in the levels of serum FSH, LH, testosterone, testis weight and sperm count, and a significant increase in sperm abnormalities by irradiation of the mouse brain with 2 Gy of (12)C6+ ion or 60Co gamma-ray. Moreover, the effects were more obvious in the group irradiated by (12)C6+ ion than in that irradiated by 60Co gamma-ray. Pre-exposure with low-dose (12)C6+ ion or 60Co gamma-ray significantly alleviated the harmful effects induced by a subsequent high-dose irradiation.

Animals↗
PubMed2006

In vitro characteristics of poly(lactic-co-glycolic acid) microspheres incorporating gelatin particles loading basic fibroblast growth factor.

AIM: To construct a sustained drug release system for basic fibroblast growth factor (bFGF). With this special system, bFGF can be used to repair an injured peripheral nerve, injured spinal cord, or as a carrier for other drugs that need to be released over a long time. METHODS: Microsphere composite was prepared by encapsulating bFGF into gelatin particles with poly(lactic-co-glycolic acid) (PLGA) as its outer-coating. The encapsulation was conducted by a phase separation method. RESULTS: The average diameter of the gelatin particle-PLGA microsphere composite was 5-18 mum, and bFGF-loading efficiency was up to 80.5%. The bFGF releasing experiment indicated that this new composite system could release bFGF continuously and protect bFGF from denaturation. CONCLUSION: A modified approach was successfully employed to develop a biodegradable system for sustained release of the drug of bFGF in vitro.

Delayed-Action Preparations↗
PubMed2006

Controlled synthesis of manganese oxohydroxide (MnOOH) and Mn3O4 nanorods using novel reverse micelles.

Novel reverse micelles of high CTAB concentration were successfully developed to synthesize MnOOH (manganese oxyhydroxide) nanorods with uniform diameters of about 10 nm and up to 200 nm in length under mild solution conditions and Mn3O4 nanorods with the same morphology could be obtained by calcining the precursors at 450 degrees C. The morphology and microstructure of the nanorods were investigated by transmission electron microscopy (TEM and HRTEM), XRD and TGA. The results showed that the concentration of CTAB was a key factor for the formation of MnOOH nanorods and only above 0.2 M the nanorods could be obtained. Moreover, the length of nanorods increased with the increase of CTAB concentration, while the diameter of nanorods retained steadily. In this way, the length of nanorods could be easily controlled from tens nanometers to hundreds nanometers by increasing the CTAB concentration from 0.35 M to 1.25 M. In addition, in our experiment the products were almost entirely rod-like shape, which indicated this method should be suitable for mass-producing.

Colloids↗
PubMed2006

Germ cell loss induced by 12C6+ ion irradiation in young female mice.

The ovaries of Kun-Ming strain mice (3 weeks) were irradiated with different doses of 12C6+ ion in the Bragg peak or the plateau region. At 10th day after irradiation, ovarian and uterine weights were measured; normal and atretic (identified with the oocyte to be degenerating or absent) primordial, primary and preantral follicles were identified in the largest cross-section of each ovary. Percentage (%) of normal follicles of each developmental stage of oogenesis was calculated. The data showed that compared to controls, there was a dose-related decrease in percentage of normal follicles in each developmental stage. And the weights of ovary and uterus were also reduced with doses of irradiation. Moreover, these effects were much more significant in the Bragg peak region and the region close to the Bragg peak than in the beam's entrance (the plateau region). Radiosensitivity varied in different follicle maturation stages. Primordial follicles, which are thought to be extremely sensitive to ionizing irradiation, were reduced by 86.6%, while primary and preantral follicles reduced only by 72.5% and 61.8% respectively, by exposure with 6 Gy of 12C6+ ion in the Bragg peak region and the region close to the Bragg peak. The data suggested that due to their optimal depth-dose distribution in the Bragg peak region, heavy ions are ones of the best particles for radiotherapy of tumors located next of vital organs or/and surrounded by normal tissues, especially radiosensitive tissues such as gonads.

Animals↗
PubMed2006

[Ameloblastoma recurrence in the grafted iliac bone: report of three cases].

Three cases of ameloblastoma recurrence in the grafted iliac bone were treated at the Department of Oral and Maxillofacial Surgery, Hospital of Stomatology, Wuhan University from 1989 to 2005. Pathologically, two cases were follicular type and the other one was plexiform type. The recurrences occurred in the bone grafts in 3, 4 and 16 years respectively after the primary operation. It is recommended that block excision with at least 1cm of normal bone be required when the resultant defect is reconstructed with autogenous bone graft. A long-term followed-up of more than 10 years at regular intervals is also recommended after the operation of classic ameloblastoma.

Ameloblastoma↗
PubMed2006

[Construction of VEGF recombinant plasmid pcDNA/V and its expression in model rats with acute myocardial ischemia].

The cDNA encoding human Vascular Endothelial Growth Factor 165 (VEGF165) was amplified using RT-PCR from human tonsil tissue and cloned into eukaryotic expression vector pcDNA3.1 (+). The recombinant plasmid pcDNA/V was transferred into 293 cells mediated by liposome and the cells stably expressing VEGF were selected under the pressure of G418. ELISA and Western blotting demonstrated that the eukaryotic expression vector pcDNA/V was successfully constructed and its corresponding protein could be expressed efficiently in vitro. Chick Charioallantoic Membrane (CAM) bioassay showed that recombinant protein has biological activity of hVEGF. Model rats with acute myocardial ischemia were used to further study the expression of VEGFin vivo. The model rats were divided randomly into three groups: control group, pcDNA3.1 (+) group and pcDNA/V group. 50microL naked plasmid DNA or saline was intramyocardially injected at three sites into the border zone of infarction. The hearts of rats were excised and fixed histologically, then the infarction sizes were studied by immunohistochemical staining and electron microscope after four weeks. Immunohistochemical staining for VEGF appeared to be negative in control and pcDNA3.1 (+) groups. In pcDNA/V group, myocardial cells in infarction border zone showed positive staining for VEGF in cytoplasm. Ultrastructural anaylsis showed that there were visible hyperplasia of vascular endothilium in pcDNA/V group. The control and pcDNA3.1 (+) groups showed less capillary hyperplasia. In this study, VEGF165 gene was successfully cloned and its protein expressed in vitro and in vivo was of bioactivity, which provides a basis for the further study of biological functions of human VEGF.

Animals↗
PubMed2006

[Clinical analysis about survival condition of different types of platysma myocutaneous flaps].

OBJECTIVE: To compare the postoperative outcome among different types of platysma myocutaneous flaps by reviewing 54 cases. METHODS: From 1984 to 2004, 54 patients with oral cancer underwent immediate reconstruction of intraoral defects using the platysma myocutaneous flaps. In 54 cases, 12 cases were transversal platysma myocutaneous flaps and the other 42 cases were vertical platysma myocutaneous flaps. In these 42 cases, 26 cases preserved facial artery and vein yet 16 cases didn't preserve them. The survival condition of these flaps were compared. RESULTS: In the 12 cases of transversal platysma myocutaneous flaps, 10 cases survived totally and 2 cases had partial necrosis. In the 26 cases of vertical platysma myocutaneous flaps preserved facial artery and vein, 23 cases survived completely and 3 cases had partial necrosis. However, in the 16 cases of vertical platysma myocutaneous flaps in that facial artery and veins were not preserved, 10 cases survived completely, whereas 4 cases had partial necrosis and 2 cases had complete necrosis. CONCLUSIONS: The survival rates of platysma myocutaneous flaps that didn't preserve facial artery and vein were low. Its clinical use should be prudent.

Adult↗
PubMed2006

[Comparative study of nanosized and microsized silicon dioxide on spermatogenesis function of male rats].

OBJECTIVE: To compare the effects of nanosized and microsized silicon dioxide on spermatogenesis function of male rats exposed by inhalation. METHODS: 45 male rats were randomly divided into control group and four experimental groups which were exposed by 100 mg/m3 or 300 mg/m3 nanosized and microsized silicon dioxide in inhalation chambers 2 hours every other day. Age-matched rats were exposed to room air with the same condition and served as controls. 65 days later, the testicular and epididymal viscera coefficients, the quantity and quality of sperm were examined and the histopathological assessment was done. The changes in biochemical parameters in serum and testes were also measured. RESULTS: Nanosized silicon dioxide could induce histopathological changes of testes in rats, and the effect was higher than that of microsized particles at the same concentration. Nanosized silicon dioxide could reduce the sperm counts of rats and the testicular LDH-C4 activities, increase MDA levels in the testes and the effect was higher than that of microsized particles at the same concentration. Nanosized silicon dioxide could lead to the reduction of sperm motility, testicular LDH-C4 activities and 8-hydroxydeoxyguanosine (8-OHdG) concentration in serum elevation in particles-exposed rats compared with the control animals, but there are no significant difference compared with that of microsized particles at the same concentration. CONCLUSION: The present findings suggest a different effect of impairment of sperm production and maturation induced by inhalation of nanosized and microsized silicon dioxide, and nanosized silicon dioxide exerted more severe reaction.

Animals↗
PubMed2006

[Signaling pathways regulating self-renewal of mouse embryonic stem cells--review].

Mouse embryonic stem cells (ES cells) are pluripotent in that they can give rise to almost all the cell types in vitro and in vivo. Also, they can sustain self-renewal in vitro owing to symmetrical mitosis, i.e., only the cell number increases while the daughter cells remain pluripotent. Self-renewal and pluripotency of ES cells are under stringent regulation of several signaling pathways. Activation of either JAK-STAT3 or PI3K, the downstream cascade of gp130, can maintain the self-renewal of ES cells, while phosphorylation of another gp130-related branch, SHP2-Ras-ERK, drives the differentiation. BMP2/4-mediated signaling is capable of suppressing the differentiation of ES cells in collaboration with activated JAK-STAT3 under serum free culture conditions. Other signaling such as Wnt also contributes to the self-renewal of ES cells. Generally, the network, which is composed of various signaling pathways, modulates the self-renewal and differentiation of mouse ES cells precisely. This review focuses on the role of gp130 in proliferation of mouse ES cells including inhibitory effect of JAK-STAT3 pathway activation on differentiation of mouse ES cells, maintenance effect of PI3K pathway activation on self-renewal of ES cells, promotive effect of SHP-2-Ras-ERK pathway activation on differentiation of ES cells, and influence of other signaling pathways on self-renewal of mouse ES cells, including maintenance effect of BMP combination with LIF under serum free culture conditions on self-renewal of ES cells and promotive effect of Wnt pathway activation on self-renewal of ES cells.

Animals↗
PubMed2005

Attenuation of amyloid beta (Abeta)-induced inhibition of phosphatidylinositol 4-kinase activity by Abeta fragments, Abeta20-29 and Abeta31-35.

We previously reported that pathophysiological concentrations of amyloid beta protein (Abeta25-35, 0.1-10 nM) directly inhibited type II phosphatidylinositol 4-kinase (PI4KII) activity in neuronal plasma membranes, which resulted in the enhanced glutamate neurotoxicity. In the present study, we examined the effects of Abeta fragments, Abeta20-29 and Abeta31-35, on the 10 nM Abeta25-35- or Abeta1-42-induced inhibition of PI4KII activity. Both of the peptide fragments recovered the inhibition of rat brain plasma membrane PI4KII activity over the concentration range of 0.1-5 nM. Such protection by the Abeta fragments was observed in the 10 nM Abeta25-35-induced inhibition of recombinant human PI4KII, suggesting that these Abeta fragments blocked the inhibition on PI4KII molecule. The Abeta25-35-induced enhancement of glutamate neurotoxicity was also completely inhibited in the presence of these fragments. Thus, Abeta20-29 and Abeta31-35 ameliorated the Abeta-enhanced glutamate neurotoxicity probably through attenuation of Abeta-induced inhibition of PI4KII activity.

Amyloid beta-Peptides↗
PubMed2005

Spinal glial activation in a new rat model of bone cancer pain produced by prostate cancer cell inoculation of the tibia.

Studies suggest that astrocytes and microglia in the spinal cord are involved in the development of persistent pain induced by tissue inflammation and nerve injury. However, the role of glial cells in bone cancer pain is not well understood. The present study evaluated the spinal glial activation in a novel rat model of bone cancer pain produced by injecting AT-3.1 prostate cancer cells into the unilateral tibia of male Copenhagen rats. The structural damage to the tibia was monitored by radiological analysis. The thermal hyperalgesia, mechanical hyperalgesia and allodynia, and spontaneous flinch were measured. The results showed that: (1) inoculation of prostate cancer cells, but not the vehicle Hank's solution, induced progressive bone destruction at the proximal epiphysis of the tibia from day 7-20 post inoculation; (2) the inoculation also induced progressive thermal hyperalgesia, mechanical hyperalgesia, mechanical allodynia, and spontaneous flinches; (3) astrocytes and microglia were significantly activated in the spinal cord ipsilateral to the cancer leg, characterized by enhanced immunostaining of both glial fibrillary acidic protein (GFAP, astrocyte marker) and OX-42 (microglial marker); (4) IL-1beta was up-regulated in the ipsilateral spinal cord, evidenced by an increase of IL-1beta immunostained astrocytes. These results demonstrate that injection of AT-3.1 prostate cancer cells into the tibia produces progressive hyperalgesia and allodynia associated with the progression of tibia destruction, indicating the successful establishment of a novel male rat model of bone cancer pain. Further, bone cancer activates spinal glial cells, which may release IL-1beta and other cytokines and contribute to hyperalgesia.

Animals↗
PubMed2005

Isolation and expression pattern of RGS21 gene, a novel RGS member.

Regulators of G-protein signaling (RGS) proteins are known for the RGS domain that is composed of a conserved stretch of 120 amino acids, which binds directly to activated G-protein alpha subunits and acts as a GTPase-activating protein (GAP), leading to their deactivation and termination of downstream signals. In this study, a novel human RGS cDNA (RGS21), 1795 bp long and encoding a 152-amino acid polypeptide, was isolated by large-scale sequencing analysis of a human fetal brain cDNA library. Unlike other RGS family members, RGS21 gene has no additional domain/motif and may represent the smallest known member of RGS family. It may belong to the B/R4 subfamily, which suggests that it may serve exclusively as a negative regulator of alphai/o family members and/or alphaq/11. PCR analysis showed that RGS21 mRNA was expressed ubiquitously in the 16 tissues examined, implying general physiological roles.

Amino Acid Sequence↗
PubMed2005

Electroacupuncture suppresses spinal expression of neurokinin-1 receptors induced by persistent inflammation in rats.

It has been demonstrated that electroacupuncture (EA) significantly suppresses behavioral hyperalgesia in a rat model of persistent inflammatory pain and that neurokinin-1 (NK-1)/substance P (SP) receptors play important roles in nociception and hyperalgesia at the spinal cord level. The present study investigated spinal NK-1 receptor involvement in EA-produced suppression of hyperalgesia in a rat model of persistent inflammatory pain. The results showed that hind paw inflammation induced a significant increase of NK-1 receptor expression in the spinal dorsal horn and that this effect was significantly suppressed by EA. This suggests that EA-induced suppression of hyperalgesia is involved, at least partly, in the suppression of the spinal NK-1 receptors induced by sustained peripheral nociceptive input.

Animals↗
PubMed2005

Mu opioid receptor-containing neurons mediate electroacupuncture-produced anti-hyperalgesia in rats with hind paw inflammation.

Previous studies showed that electroacupuncture (EA) significantly attenuates inflammatory hyperalgesia in a complete Freund's adjuvant (CFA)-induced inflammatory pain rat model. The present study demonstrates that pretreatment with Derm-sap, a selective toxin for neurons that contain mu opioid receptor (MOR), specifically decreases MOR and blocks EA anti-hyperalgesia. These data suggest that spinal MOR-containing neurons are involved in the processes by which EA produces anti-hyperalgesia.

Analysis of Variance↗