PubMed Health⌕ Search

Biomedical subjects

H Zhang

Publications and source records attributed to H Zhang.

At least 415 records · Page 23Linked to original sources
PubMed2001

Excitatory amino acids in cerebrospinal fluid of patients with acute head injuries.

BACKGROUND: The excitatory amino acids (EAAs) glutamate (Glu) and aspartate (Asp) play a role in the pathogenesis of postischemic and posttraumatic brain insult. The changes of EAAs in cerebrospinal fluid (CSF) of patients with traumatic brain injury are incompletely understood. METHODS: We used reversed-phase HPLC with precolumn derivatization with o-phthalaldehyde and fluorescence detection to measure Glu and Asp in CSF of 42 patients with acute head injury and 9 control adults without neurologic diseases. We assessed the Glasgow Coma Scale (GCS) on admission, the main lesion patterns on computed tomography (CT) scan within 24 h post trauma, and the Glasgow Outcome Scale (GOS) 3 months post injury. RESULTS: The mean concentrations of Glu and Asp in CSF in the brain-injured group were significantly higher than those of the control group (Glu, P <0.001; Asp, P <0.05). In patients admitted within 24 h after severe injury (n = 13), peak Glu values appeared within 48 h in 11 patients (85%), and the mean value remained higher than control values at day 7 (P <0.02). The concentrations of EAAs were higher in patients with severe injuries (GCS < or =8) than in those with milder injuries (Glu, P <0.001; Asp, P <0.05). GCS and peak EAAs correlated negatively (Glu, rs = -0.5706, P <0.001; Asp, rs = -0.5503, P <0.001). The patients with focal brain contusion on initial CT scan (n = 8) had a significantly lower peak Glu value than the patients with other patterns (n = 8-15; P <0.02 to 0.001). The peak value of EAAs in the poor-outcome group (including severe disability, vegetative state, and death) was significantly higher than in the good-outcome group (good recovery and moderate disability; Glu, P <0.001; Asp, P <0.01); GOS was closely correlated to the EAA values (Glu, rs = 0.5737, P <0.001; Asp, rs = 0.5470, P <0.001). CONCLUSIONS: The EAA concentrations in CSF increase after acute head injury and remain higher for at least 1 week post injury in severely injured patients. The more severe the trauma, the more obvious the excitotoxicity induced by EAAs and the worse the outcome.

Acute Disease↗
PubMed2001

Growth factor regulation of neutrophil-endothelial cell interactions.

The effects of the angiogenic factors basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) on human polymorphonuclear leukocyte (PMNL)-endothelial cell adhesion and transendothelial migration (TEM) were investigated. Stimulation of human umbilical vein endothelial cells by VEGF or bFGF for 18 h up-regulated intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 expression and significantly increased PMNL adhesion and TEM in response to complement fragment 5a (C5a) or interleukin (IL)-8. In contrast, continued exposure to bFGF (24 h-6 days) down-regulated basal and IL-1- or tumor necrosis factor (TNF)-induced intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and E-selectin expression as well as PMNL adhesion and TEM. These effects could be reversed by introduction of high concentrations of TNF-alpha, C5a, or IL-8. None of these inhibitory effects was observed with VEGF. The acute effects of bFGF and VEGF may facilitate PMNL emigration during acute inflammation, but continued bFGF production may have anti-inflammatory actions during chronic inflammation, angiogenesis, and tumor defense by inhibition of endothelial activation for leukocyte recruitment.

Cell Adhesion↗
PubMed2001

Chlamydial nucleic acids in synovium in osteoarthritis: what are the implications?

OBJECTIVE: To study whether there is evidence of bacterial DNA in some osteoarthritic (OA) joint tissues, and the clinical implications of finding bacterial DNA in this relatively noninflammatory disease. METHODS: Polymerase chain reaction (PCR) was used to detect DNA of Chlamydia trachomatis, Chlamydia pneumoniae, and other bacteria using panbacterial primers in synovial membranes and other articular tissues of 32 consecutive patients undergoing surgery for hip and knee OA. Patients were interviewed and examined postoperatively. Operative reports were reviewed and followup examinations were accomplished on all patients. RESULTS: Nine of 32 patients with OA (28.1%) had evidence for bacterial DNA in joint tissues with at least one set of primers for Chlamydia: 7 for C. trachomatis (21.9%), 2 for C. pneumoniae (6.2%). Five of 32 (15.6%) patients had postoperative complications; 3 of these were in patients who showed amplified DNA of C. trachomatis in joints and one in a patient in whom we detected Escherichia coli. CONCLUSION: C. trachomatis and C. pneumoniae nucleic acids can be present in joints in some cases of apparently classical OA. Whether chlamydial or other difficult to culture bacterial presence is associated with complications is suggested, but remains to be determined. Simple presence of C. trachomatis by PCR does not define a clinical syndrome or disease course.

Aged↗
PubMed2001

[Construction and expression in eukaryotic cells of HBsAg and B].

OBJECTIVE: To investigate the enhanced role of B(7-1) in gene immunization of eukaryotic vector expressing HBsAg, and further to eliminate the immunotolerance to hepatitis B virus. METHODS: B(7-1) and IRES-HBs with linker and promoter sequence prior to HBs gene were amplified with high fidelity PCR, then subcloned into plasmid pBluescriptks+, which was used to sequence. The eukaryotic expressing vector was constructed by inserting B(7-1) and IRES-HBs into plxsn. Recombinant vector was transfected into PA317 by means of lipid mixtures. Titre of pseudovirus packaged in PA317 cells was detected by infecting NIH3T3 cells. B(7-1) and HBsAg expression in PA317, NIH3T3, HepG(2), 293, EL4 cell lines was detected by RT-PCR, immunohistochemistry and ELISA, respectively. RESULTS: No change was found in the sequences of target genes amplified by high fidelity PCR compared with the known sequences. Plxsn-B(7-1)-HBs was constructed by first inserting B(7-1) into plxsn with enzyme EcoRI/XhoI, then IRES-HBs was inserted in the same way with enzyme XhoI/BamHI. 43 and 90 G418-resistant clones were obtained two weeks later after 1:10 and 1:5 passages at 24 hours after transfection. Titre of the peudovirus was 5.4x10(5) CFU/ml. B(7-1) was expressed in all the cell lines above by RT-PCR test. The contents of HBsAg in the supernatant of the PA317, NIH3T3, HepG(2), and 293 cells at 24, 48, 72 hours intervals were 0.15, 0.11, 0.20, 0.13; 0.63, 0.47, 0.76, 0.58; 0.77, 0.61, 0.89, 0.69, respectively. CONCLUSIONS: The retroviral vector expressing B(7-1) and HBsAg simultaneously is constructed successfully. The target antigens are expressed in above cell lines in vitro after transfection with lipids mixtures. It may be used to conduct gene immunization and to investigate the role of B(7-1) on HBsAg immune response, which may be further used to the prevention and therapy of hepatitis B.

Animals↗
PubMed2001

[Detection of spikes in epileptic EEG based on Multiresolution Tsallis' entropy].

In this paper, the detection of the spikes in the epileptic EEG signal was studied based on Multiresolution Tsallis' entropy (MRET). First, EEG signals were decomposed into wavelet series, and then, at every scale, the abnormal spikes were distinguished from normal background EEG activities by using MRET. The analysis of 6 patients' EEG data showed that the abnormal epileptiform spikes in EEG can be accurately detected with this method, which opens up the perspectives of building up automatic detection devices for spikes in EEG. Compared with the Shannon entropy, the MRET provides one with more detailed information.

Electroencephalography↗
PubMed2001

[Effect of simulated weightlessness on the apoptosis of thymus cells in tail-suspended mice].

OBJECTIVE: To investigate the effect of simulated weightlessness on apoptosis of thymus cells in mice. METHOD: Tail-suspended mice were used as an animal model of simulated weightlessness; chromosome breakage was measured by PI staining, and changes of cell membrane were determined by Annexin-V analysis. RESULT: As compared with the control, there was no obvious chromosome breakage; the total number of apoptotic cells and number of early apoptotic cells increased in 1 d suspended group; the number of early apoptotic cells increased significantly and the total number of apoptotic cells increased very significantly in 2d suspended groups. CONCLUSION: These results suggested that simulated weightlessness could promote apoptosis of thymus cells.

Animals↗
PubMed2001

Cryopreservation of suckling pig hepatocytes.

To determine the best and simplest method for cryopreservation of pig hepatocytes, we compared immediate cryopreservation with cryopreservation after short-term culture. Suckling pig hepatocytes were isolated by a modified 2-step in situ collagenase perfusion method, suspended in serum-free medium, and preserved for 10 da by two cryopreservation methods. Serial measurements were made of cell viability, LDH release, synthesis of protein, urea and glucose, glucose-6-phosphatase (G-6-Pase) activity, and diazepam transformation after thawing. These measurements were performed on both groups of cultured hepatocytes, and on freshly isolated hepatocytes, which served as a control. High viability (>95%)of thawed hepatocytes was obtained and maintained in both cryopreservation groups. There were no significant differences in cell viability, protein synthesis, glucose synthesis, G-6-Pase activity, or diazepam transformation between the two cryopreservation groups. In the immediate cryopreservation group, urea synthesis was less than in the group with cryopreservation after short-term culture. Protein synthesis, glucose synthesis, and diazepam transformation were lower in both cryopreserved groups than in the controls. The results showed that a protocol of immediate cryopreservation of hepatocytes in RPMI-1640 medium containing 10% DMSO, hormones, growth factors, and 10% newborn bovine serum, together with rate-controlled freezing and rapid thawing, provides indices of cell viability and function during subsequent serum-free culture that are comparable to hepatocytes cryopreserved after short-term culture, except for lower urea production. This simple procedure can be used in studies of bioartificial liver and hepatocyte transplantation.

Animals↗
PubMed2001

[Relationship between EGG and the dynamic process of motion sickness induced by optokinetic vection].

OBJECTIVE: To investigate the correlation between Electrogastrography (EGG) and the occurrence of nausea or/and vomit as well as the development of motion sickness (MS) induced by optokinetic stimulation (OPS) and to provide a clue and method for prediction and prevention of MS. METHOD: Twenty male subjects, aged from 18 to 25 years, performed the test only once with the optokinetic drum rotated around a vertical axis at the speed of 60 degrees/s for 15 min. Nausea and EGG signals were observed and recorded. RESULT: (1)Both the increment of tachygastric percentage and the decrement of primary wave percentage of EGG in eleven subjects with nausea were significantly larger than those in nine subjects with no nausea (both P < 0.001). (2)The circular vection preceded the changes of EGG in eleven subjects with nausea while the MS scores in eleven subjects with nausea were higher than those in nine subjects with no nausea (P < 0.001). (3)During the rotation of drum, the decrement of primary wave percentage or the increment of tachygastria percentage also preceded the occurrence of nausea in eleven subjects with nausea (both P < 0.01). CONCLUSION: (l)The changes of EGG in subjects with nausea were significantly greater than those of EGG in subjects with no nausea. (2)There was a close relationship between circular vection or illusory self-rotation and EGG changes as well as the occurring of nausea induced by OPS. (3)Changes of EGG preceded the nausea of MS induced by OPS.

Adolescent↗
PubMed2001

Bid antisense attenuates bile acid-induced apoptosis and cholestatic liver injury.

Bile acids cause liver injury during cholestasis by inducing hepatocyte apoptosis by both Fas-dependent and -independent mechanisms. However, the Fas-independent apoptosis also appears to be death receptor-mediated. Because death receptor-mediated apoptosis in hepatocytes requires proapoptotic Bcl-2 BH3 domain only protein Bid, we postulated that Fas-independent but death receptor-mediated bile acid cytotoxicity would be Bid-dependent. We used Fas-deficient lymphoproliferative (lpr) mouse hepatocytes for these studies, and inhibited Bid expression using an antisense approach. Glychochenodeoxycholate (GCDC) was used to induce apoptosis. Bid cleavage and translocation to mitochondria was observed in GCDC-treated cells as assessed by immunoblot analysis and confocal imaging of Bid-green fluorescent protein, respectively. Bid translocation to mitochondria was associated with cytochrome c release. A Bid antisense 2'-MOE modified oligonucleotide inhibited Bid expression in hepatocytes and markedly attenuated hepatocytes apoptosis by GCDC. Treatment of lpr mice with Bid antisense also ameliorated liver injury following bile duct ligation of the mice, a model of extrahepatic cholestasis. These results suggest that bile acid cytotoxicity is Bid-dependent despite the absence of Fas. Bid antisense therapy is a promising approach for the treatment of cholestatic liver injury.

Animals↗
PubMed2001

Collecting aerosol in airflow with a magnetically stabilized fluidized bed.

A magnetically stabilized fluidized bed (MSB) is a highly efficient filter that takes the advantage of both fluidized beds and fixed beds. This paper presents the research to collect aerosol in airflow with a MSB. The filtering model of MSB is established with its parameters including magnetic field intensity, gas superficial velocity, average grain-size, and bed height on the collection efficiency of MSB. The model is verified by experiments.

Aerosols↗
PubMed2001

[An off site petroleum-contaminated soil bioremediation technology: soil compositing in windrow].

With off-site bioremediation technology, a soil contaminated by crude oil from Liaohe Oil Field was treated on a 20 x 10 m prepared bed. 8 composting windrow units were set, each measured 8 m in length, 2 m in width, and 0.35 m in height. The results showed that when the pollutant petroleum hydrocarbon(TPH) was within the range of 4.16-7.72 g.100 g-1 soil, the total degradation rate of TPH reached 45.19%-56.74% after 53 days operation, which indicated that a technological basis would be provided for the bioremediation of oil-contaminated soil.

Biodegradation, Environmental↗
PubMed2001

[The changes of Clara cell in the distal conducting airways of patients with COPD].

OBJECTIVE: To investigate the role of Clara cells in the pathogenesis of COPD. METHODS: Lung samples of pneumonectomy were collected from 13 patients with COPD and 13 patients without COPD. They had similar age, sex and smoke index. The number and distribution of Clara cells were measured by immunohistochemistry. The mRNA expression and protein level of CC16 were determined by riboneuclease protection assay and Western blot separately. RESULT: The number of Clara cells of the respiratory brochioli was lower in patients with COPD than in those without COPD (16.4% vs. 18.5%, P < 0.05). The expression of CC16 mRNA was also lower in patients with COPD than those without COPD(0.28 +/- 0.05 vs. 0.45 +/- 0.05, P < 0.05). There was no obvious difference of CC16 protein level between these two groups. CONCLUSION: The changes of the number and function of Clara cell may be one of the factors in the development of COPD.

Blotting, Western↗
PubMed2001

[Activation of NF-kappa B and its effect on induction of platelet-derived growth factor-B transcription by angiotensin II in ECV304 cell line].

OBJECTIVES: The renin-angiotensin system may contribute to the pathogenesis of atherosclerosis. The transcription factor nuclear factor-kappa B (NF-kappa B) participates in most signal pathways involved in the inflammatory process. In this project the effect of angiotensin II (Ang II) on NF-kappa B activation and the promotion of PDGF-B mRNA expression in human endothelial cell line ECV304 was studied. METHODS: Electrophoretic mobility shift assay, immunofluorescence and immunoelectronic microscope techniques, including confocal microscopy and gold particle labelled electronic microscopy were applied to investigate the mechanism by which Ang II activates NF-kappa B, ECV304 cells were transiently transfected with an NF-kappa B/luciferase reporter gene and catalytically inactive NIK, IKK alpha, IKK beta mutants respectively. Northern blot was carried out to detect PDGF-B mRNA. RESULTS: By the findings of immunofluorescence confocal microscopy, immunoelectronic microscopy and Northern blot, Ang II was effective in stimulating NF-kappa B activation and there was definited cytoplasmic-to-nuclear translocation of NF-kappa B subunits p50 and p65 and overexpression of PDGF-B mRNA expression. Over-expression of the transiently transfected IKK alpha-KM, IKK beta-KM and NIK-KM mutant genes enabled to block the reporter gene activation induced by ang II. CONCLUSION: Ang II is effective to activate NF-kappa B through a pathway dependent on NIK, IKK alpha and IKK beta, and induces PDGF-B transcription in the endothelial cell line ECV304.

Angiotensin II↗
PubMed2001

[Photobacterium phosphoreum assay on the toxicity of soil contaminated by heavy metals].

The toxicity of soil artificially contaminated by heavy metals was assessed with Photobacterium phosphoreum. The results showed that the duration of optimum balance was 24 hours, and that of optimum extraction was 2 hours. Two leaching methods were compared, and data showed that optimum leaching solvent was hydrocarbon chloride with a concentration of 0.1 mol.L-1 HCL. Dose-response curve indicated that the content of heavy metals was positively related with the toxicity of soil. The general detection limit given by EC50 of soil contaminated by single heavy metal were Cd 26.12 mg.kg-1, Cu 291.48 mg.kg-1, Zn 72.46 mg.kg-1 and Pb 2174.93 mg.kg-1. This study also indicated the toxicity of complex heavy metals pollution in soil was stronger than that of individual element. The research could provide a theoretic base for the remediation of soil contaminated by heavy metals.

Cadmium↗
PubMed2001

[Co-metabolic degradation of pyrene in soil].

High molecular weight Polycyclic Aromatic Hydrocarbons (PAHs) are always degraded by means of co-metabolism. This study compared the degradation process of pyrene as sole source of carbon and energy and co-metabolic degradation process of pyrene. The degradation rate of pyrene after 25 days in the first process was 57%, while the degradation rate of pyrene in the co-metabolic processes were about 80%. The half-life of pyrene in the co-metabolic process was shorter than those in the processes without co-metabolism. Salicylic acid, phthalic acid, sodium succinate could serve as co-metabolic substrate to enhance the degradation rate of pyrene, and sodium succinate has the best effect. There was co-metabolic relationship between pyrene and phenanthrene which was a kind of low molecular weight PAHs, phenanthrene accelerated the degradation of pyrene, while naphthalene didn't. The principle of the co-metabolism and the optimal material used as co-metabolic substrate were demonstrated in this paper.

Environmental Pollution↗
PubMed2001

[History of the grafting of coronary artery bypass].

Great efforts had been made to treat coronary artery disease by using myocardial revascularization for a century. Evolved from the early exploration, and the early forms of direct revascularization. The grafting of coronary artery bypass began in the 1960s. Big progresses had been made in the operative technique, the grafting materials of bypass and myocardial protection etc. in the following forty years. Now it is one of the most effective therapies for coronary artery disease.

Coronary Artery Bypass↗