Biomedical subjects

Bo Hu

Publications and source records attributed to Bo Hu.

48 records · Page 3Linked to original sources

PubMed2003

Induction of increased intracellular calcium in astrocytes by glutamate through activating NMDA and AMPA receptors.

To study the effect of glutamate on the intracellular calcium signal of pure cultured rat astrocytes and the role of NMDA and AMPA receptors in the procedure, the change of calcium signal was investigated by monitoring the fluctuation of intracellular Ca2+ concentration ([Ca2+]i) on the basis of Fura-2 single cell fluorescent ratio (F345/F380). The changes in the effect of glutamate on the intracellular calcium signal were observed after blockage of NMDA and (or) AMPA receptors. It was found that L-glutamate could induce an increased [Ca2+]i in most of the cells in concentration- and time-dependent manner. D-(-)-2-amino-5-phosphonopentanoic acid (D-AP-5, a selective antagonist of the NMDA receptor) and 6-cyano-7-nitroquinoxaline-2, 3-dione (CNQX, a selective antagonist of the AMPA receptor) could abolish the effects of NMDA and AMPA respectively. The treatment of D-AP-5 and CNQX simultaneously or respectively could attenuate the effect of L-glutamate at varying degrees. All these indicated that glutamate could modulate intracellular Ca2+ of pure cultured rat astrocytes through different pathways. The activation of NMDA and AMPA receptors took part in the complex mechanisms.

Animals↗

PubMed2003

Platelet-derived growth factor-B enhances glioma angiogenesis by stimulating vascular endothelial growth factor expression in tumor endothelia and by promoting pericyte recruitment.

Platelet-derived growth factor (PDGF)-B and its receptor (PDGF-R) beta are overexpressed in human gliomas and responsible for recruiting peri-endothelial cells to vessels. To establish the role of PDGF-B in glioma angiogenesis, we overexpressed PDGF-B in U87MG glioma cells. Although PDGF-B stimulated tyrosine phosphorylation of PDGF-Rbeta in U87MG cells, treatment with recombinant PDGF-B or overexpression of PDGF-B in U87MG cells had no effect on their proliferation. However, an increase of secreted PDGF-B in conditioned media of U87MG/PDGF-B cells promoted migration of endothelial cells expressing PDGF-R beta, whereas conditioned media from U87MG cells did not increase the cell migration. In mice, overexpression of PDGF-B in U87MG cells enhanced intracranial glioma formation by stimulating vascular endothelial growth factor (VEGF) expression in neovessels and by attracting vessel-associated pericytes. When PDGF-B and VEGF were overexpressed simultaneously by U87MG tumors, there was a marked increase of capillary-associated pericytes as seen in U87MG/VEGF(165)/PDGF-B gliomas. As a result of pericyte recruitment, vessels induced by VEGF in tumor vicinity migrated into the central regions of these tumors. These data suggest that PDGF-B is a paracrine factor in U87MG gliomas, and that PDGF-B enhances glioma angiogenesis, at least in part, by stimulating VEGF expression in tumor endothelia and by recruiting pericytes to neovessels.

Animals↗

PubMed2003

[Protective effect of ginkgo biloba extract on cerebral ischemia/reperfusion injury in rats].

OBJECTIVE: To study the effect of Ginkgo biloba extract (GbE) on dynamic equilibrium of free radicals and amino-acids in cortex of rats with cerebral ischemia/reperfusion (I/R) injury and its influence and characteristics to intracellular free calcium concentration ([Ca2+]i) in primary cultured hippocampal neuron of rats. METHODS: Amino-acids were quantified by high performance liquid chromatographic (HPLC) analysis. Concentration of MDA and GSH-Px were determined by thiobarbituric acid (TBA) technique. SOD was assayed through xanthine method, and microfluoremetric technique was used to assay the change of [Ca2+]i and its characteristics. RESULTS: Compared with the non-treated groups, at all time points (3 hrs after ischemia, 1 and 2 hrs after I/R separately), in the GbE treated groups, the levels of Glu, Asp and MDA were lower and SOD and GSH-Px were higher (P < 0.01 or P < 0.05), the GABA and Gly levels were lower in groups treated with middle (10 mg/kg) or high dosage (15 mg/kg) of GbE (P < 0.05). Compared with the group treated with small dosage GbE (5 mg/kg), Glu, Asp and MDA were lower and GABA, Gly, SOD and GSH-Px were higher in the groups treated with middle or high dosage of GbE (P < 0.05), while the difference in the latter two groups was insignificant. Level of [Ca2+]i in cultured neurons treated with 1 x 10(-5) mol/L glutamate combined 25 micrograms/ml GbE for 20s was lower with lower peak value and longer time for reaching the peak than that in neurons treated with 1 x 10(-5) mol/L glutamate alone. Besides, the time of decline phase was also shorter in the former, so the flatform stage was prolonged. The response was recovered by re-applying of glutamate after [Ca2+]i back to base line. CONCLUSION: GbE can protect damaged neurons through keeping the balance of inhibitory/excitatory amino-acids, enhancing free radicals scavengers system, and inhibiting the effect of glutamate to [Ca2+]i.

Amino Acids↗

PubMed2003

[Application of St George's respiratory questionnaire in evaluating the life quality of Chinese patients with chronic obstructive pulmonary disease].

OBJECTIVE: To study the value of St George's respiratory questionnaire (SGRQ) in evaluating the life quality of Chinese patients with COPD. METHODS: The SGRQ score and spirometry were collected from 30 patients with COPD. The validity was documented by performing correlation analysis, and Pearson's correlation coefficients were calculated. Nineteen patients were reassessed after three months' treatment with inhaled glucocorticoids. Paired t test was performed to evaluate the sensitivity of SGRQ to changes of disease severity. RESULTS: The correlation coefficients between the total score and the symptoms section score, the activity section score, and the impacts section score of SGRQ were 0.61, 0.79 and 0.97, respectively. The symptoms section score, the activity section score, the impacts section score, and the total score were significantly correlated with FEV(1)% pred, and with similar coefficients (-0.4 - -0.5, P < 0.05). The result of paired t test showed that the changes of SGRQ between the two assessments were significant (P < 0.001) and consistent with changes of clinical symptoms and spirometry. SGRQ was more sensitive than spirometry in evaluating the changes of disease severity. CONCLUSION: SGRQ was a valid, sensitive and feasible method in measuring the quality of life in Chinese patients with COPD. Large-scale application in China needs to be carried out.

Female↗

PubMed2003

[The use of Juniper's asthma quality of life questionnaire in Chinese asthmatics].

OBJECTIVE: One of the most important objectives in the management of asthma is to improve the quality of life of patients. We summarized our experience in using Juniper's asthma quality of life questionnaire (AQLQ) in Chinese asthmatics. METHODS: Measurement instruments included self-administered AQLQ mandarin Chinese version and its standardized version. The data were from 210 AQLQ evaluations from 96 patients. RESULTS: AQLQ and its four domains weakly correlated with forced expiratory volume in 1 second (FEV(1)) except the environment domain (r: 0.201 - 0.284). If the asthmatic patients were graded into 4 groups based on FEV(1), AQLQ and its four domains significantly detected the differences among the groups. The change of AQLQ, however, was not correlated with the change of FEV(1). The change of AQLQ domain of symptoms was correlated with the change of peak expiratory flow. CONCLUSION: The Juniper's AQLQ performs well in Chinese asthmatics. AQLQ is correlated with pulmonary function and probably more sensitive and accurate than pulmonary function in the evaluation of disease severity.

Adult↗

PubMed2002

A new monoterpene from the bark of Eucommia ulmoides.

A new monoterpene, eucommidiol (1), was isolated from the bark of Eucommia ulmoides Oliv. (Eucommiaceae), together with a known compound 1,4a,5,7a-tetrahydro-7-hydroxymethyl-cyclopenta[c]pyran-4-carboxylic methyl ester. The structure of 1 was characterized as 6,6a-di(hydroxymethyl)-3,3a,4,6a-tetrahydro-2H-cyclopenta[b]furan-2-one on the basis of chemical and spectral evidence including 2DNMR studies.

Eucommiaceae↗

PubMed2002

Central sensitization of nociceptive neurons in trigeminal subnucleus oralis depends on integrity of subnucleus caudalis.

Our recent studies have shown that application to the tooth pulp of the inflammatory irritant mustard oil (MO) produces a prolonged (>40 min) "central sensitization" reflected in neuroplastic changes in the mechanoreceptive field (RF) and response properties of nociceptive brain stem neurons in subnuclei oralis (Vo) and caudalis (Vc) of the trigeminal spinal tract nucleus. In view of the previously demonstrated ascending modulatory influence of Vc on Vo, our aim was to determine whether the Vo neuroplastic changes induced by MO application to the tooth pulp depend on an ascending influence from Vc. In chloralose/urethan-anesthetized rats, MO application to the pulp produced significant increases in Vo nociceptive neuronal orofacial RF size and responses to mechanical noxious stimuli that lasted as long as 40-60 min. These changes were not affected by vehicle (saline) microinjected into Vc at 20 min after MO application, but 0.3 microl of a 5 mM CoCl(2) solution microinjected into the ipsilateral Vc produced a reversible blockade of the MO-induced Vo neuroplastic changes. A similar volume and concentration of CoCl(2) solution injected into subnucleus interpolaris of the trigeminal spinal tract nucleus did not affect the MO-induced neuroplastic changes in Vo. These findings indicate that inflammatory pulp-induced central sensitization in Vo is dependent on the functional integrity of Vc.

Animals↗

PubMed2002

P2X receptors in trigeminal subnucleus caudalis modulate central sensitization in trigeminal subnucleus oralis.

This study investigated the role of trigeminal subnucleus caudalis (Vc) P2X receptors in the mediation of central sensitization induced in nociceptive neurons in subnucleus oralis (Vo) by mustard oil (MO) application to the tooth pulp in anesthetized rats. MO application produced a long-lasting central sensitization reflected in neuroplastic changes (i.e., increases in neuronal mechanoreceptive field size and responses to innocuous and noxious mechanical stimuli) in Vo nociceptive neurons. Twenty minutes after MO application, the intrathecal (i.t.) administration to the rostral Vc of the selective P2X(1), P2X(3), and P2X(2/3) receptor antagonist, 2'-(or 3'-)O-trinitrophenyl-ATP (TNP-ATP), significantly and reversibly attenuated the MO-induced central sensitization for more than 15 min; saline administration had no effect. Administration to the rostral Vc of the selective P2X(1), P2X(3), and P2X(2/3) receptor agonist, alpha,beta-methylene ATP (alpha,beta-meATP, i.t.) produced abrupt and significant neuroplastic changes in Vo nociceptive neurons, followed by neuronal desensitization as evidenced by the ineffectiveness of a second i.t. application of alpha,beta-meATP and subsequent MO application to the pulp. Administration to the rostral Vc of the selective P2X(1) receptor agonist beta,gamma-methylene ATP (beta,gamma-meATP, i.t.) produced no significant neuroplastic changes per se and did not affect the subsequent MO-induced neuroplastic changes in Vo nociceptive neurons. These results suggest that P2X(3) and possibly also the P2X(2/3) receptor subtypes in Vc may play a role in the initiation and maintenance of central sensitization in Vo nociceptive neurons induced by MO application to the pulp.

Adenosine Triphosphate↗

PubMed2002

[A preliminary study of pentanucleotide repeat polymorphism of apolipoprotein(a) gene in coronary atherosclerotic heart disease].

OBJECTIVE: This study inquired into the relationship between a pentanucleotide repeats(PNR) polymorphism of the apolipoprotein(a)[apo(a)] gene and coronary atherosclerotic heart disease(CHD) in Chinese Han nationality. METHODS: PNR polymorphism of the apo(a) gene from 165 cases of CHD and 153 normal individuals were analyzed by polymerase chain reaction(PCR)-denature polyacrylamide gel electrophoresis-silver stain. RESULTS: The frequencies of (TTTTA)(5/8) genotype (0.188) and (TTTTA)(5) allele (0.115) in CHD group were remarkably higher than those in control group (0.039, 0.026)(P<0.01, P<0.05). CONCLUSION: These findings indicate that the PNR polymorphism of apo(a) is associated with the susceptibility to CHD, which may be involved in the development of CHD.

Aged↗

PubMed2002

Vascular endothelial growth factor gene transfer improves host endothelialization of xenogeneic biologic heart valve in vivo.

OBJECTIVE: To investigate the feasibility of endothelialization of bioprosthesis by transfer of vascular endothelial growth factor (VEGF) gene. METHODS: Bovine pericardium treated with glutaraldehyde and L-glutamic acid was positioned into the pig right atrium. pcD(2)/hVEGF(121) gene (1 mg) was transferred into the right ventricular myocardium using surgical sutures Reverse transcri ption polymerase chain reaction (RT PCR) was employed to evaluate the expression of myocardial VEGF mRNA. The determination of concentrations of VEGF protein in blood from both the right atrium and peripheral vein, and histological and ultrastructural analysis of implanted bovine pericardium were completed simultaneously. RESULTS: The concentration of VEGF derived from the right atrium in pcD(2)/hVEGF(121) group was significantly higher than that in the pcD(2) group 10 days after VEGF gene transfer (P < 0.01). The expression of myocardial VEGF mRNA in pcD(2)/hVEGF(121) group was much higher in comparison with that in the pcD(2) group. The morphological analysis demonstrated that the coverage rate of host endothelium in the pcD(2)/hVEGF(121) group was 2.6 times as fast as that in the pcD(2) group at 16 days after VEGF(121) gene transfer (P < 0.01). Entire endothelialization occurred at 30 days after VEGF gene transfer. In addition, higher expression of myocardial VEGF mRNA was still available. CONCLUSIONS: VEGF gene transfer by surgical suture can remarkably accelerate endothelialization of bioprosthesis, which may provide a new approach for inhibiting biological valve calcification and improve biocompatibility and long-term durability of the bioprosthesis.

Animals↗

PubMed2002

Protective effects of Ginkgo biloba extract on rats during cerebral ischemia/reperfusion.

OBJECTIVE: To study the effect of Ginkgo biloba extract on rats during ischemia/reperfusion and its influence on intracellular calcium in hippocampal neurons. METHODS: Model of intraluminal occlusion of the middle cerebral artery (MCAO) was used to prepare the ischemia/reperfusion cortex tissue. Concentration of MDA was determined by measuring thiobarbituric acid-reactive substance. GSH-PX was quantified using the thiobarbituric acid (TBA) technique. SOD was assayed througha xanthine method. Endogenous amino acids were quantified by high performance liquid chromatographic (HPLC) analysis. Primary culturs of hippocampal neurons were prepared for a free intracellular calcium ([Ca(2+)]I) assay by Fura-2 based single cell microfluoremetric technique. RESULTS: Comparing control and treatment groups, the concentration of SOD and GSH-PX were higher, whereas that of MDA was much lower; the concentration of glutamate and aspartate decreased and that of GABA increased markedly at all time point (P < 0.01), Gly also decreased at some time points (P < 0.05). The differences were significant between the groups of 10 mg/kg, 15 mg/kg and the groups of 5 mg/kg. When 1 x 10(-5) mol/L glutamate was applied with 25 micro g/ml ginkgo biloba extract to cultured neurons, the increase in [Ca(2+)]I was lower than that caused by applying glutamate alone. Its peak value was much lower and increased phase was longer, its declining phase was shorter. After returning to baseline, the application of 1 x 10(-5) mol/L glutamate could induce the reaction to recover. CONCLUSIONS: Ginkgo biloba extract could protect damaged neurons by keeping the balance of inhibitory/excitatory aminoacids, enhancing the free radical scavengers system, and inhibiting the effect of glutamate on [Ca(2+)]I.

Amino Acids↗

PubMed2002

[Spectra characteristics of the complexes of glucosamine and carboxymethyl glucosamine with ferrum(II), zinc(II), cobalt(II) and copper(II)].

This article investigated UV, IR and 1H-NMR spectra characteristics of the complexes which are formed by glucosamine and Fe (II), Zn (II), Co (II), Cu (II) respectively. The UV's lambda max of the complexes makes obvious violet shift when compared with that of the glucosamine. In IR spectra of the complexes, out-of-plane vibration peak 655 cm-1 of the amino group is lower than that of the glucosamine which is 670 cm-1, and there is also the new absorption peak near 990 cm-1. As for 1H-NMR, the C3 hydroxy proton and the amino proton of the complexes absorb highfield when compared with that of glucosamine, while the shifts of the hydroxy proton on other carbon atoms remain unchanged or almost unchanged, so the formation of the nitrogen-metal bond is primarily proved. This article also researched the syntheses of the complexes of the carboxymethyl glucosamine with Fe (II), Co (II), Cu (II) and pointed out that it is the rigidity of the sugar ring that leads to an abnormal phenomenon that the spectral lines' number of the complexes is the same as that of the carboxymethyl glucosamine. Their IR and UV spectra all indicate that there is no peak of the free carbonyl group in the molecule and prove the existence of inner salt. In the complexes' IR spectra, the formation of the oxygen-metal bond accounts for the appearance of a series of new absorption peaks: 433.1 and 408.9 cm-1 (O-Fe), 507.1 and 495 cm-1 (O-Co), 403.1 and 389 cm-1 (O-Cu).

Cobalt↗