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Biomedical subjects

Xiang Zhang

Publications and source records attributed to Xiang Zhang.

90 records · Page 5Linked to original sources
PubMed2003

[Changes and effects of group II metabotropic glutamate receptors in the cerebral cortex of rats after diffuse brain injuries coupled with hypopiesia secondary brain insults].

OBJECTIVE: To study the changes and effects of group II metabotropic glutamate receptors (mGluR) after diffuse brain injuries (DBI) coupled with hypopiesia secondary brain insults (SBI). METHODS: Male SD rats were randomized into four groups: normal control, sham-operated, DBI alone and DBI coupled with SBI group. The SBI model was made on the basis of Marmarou's model. The mRNAs of the mGluRs were detected at 1, 3, 6, 12, 24, 48 and 72 hours after injuries by in-situ hybridization, and the positive neurons were counted. RESULTS: Statistical analysis showed no significance between normal control group and sham-operated group, DBI group in mGluR 2, 3 mRNA (all P>0.05). The number of mGluR 2, 3 positive neurons decreased at 12 hours after injury and the peak occurred at 48 hours after injury in the injured cerebral cortex in DBI alone group (both P<0.05). However, in DBI with SBI group, there was a significant decrease of the number of mGluR2, 3 positive neurons at 6 hours after injury and the peak happened at 24 hours after injury (both P<0.05). CONCLUSION: mGluR2, 3, factors with the function of protecting brain, might play an important role in the path physiology of DBI and SBI.

Animals↗
PubMed2003

[Protective effect of Rheum tanguticum polysaccharides (RTP) on traumatic brain injury in rats].

OBJECTIVE: To evaluate protective effects of Rheum tanguticum polysaccharides (RTP) on traumatic brain injury (TBI) in rats. METHOD: The polysaccharides (RTP) were extracted from Tanguficum Maxim. 120 rats were divided into 15 groups, with 8 rats in each group. RTP at 100, 200 and 400 mg x kg(-1) were administrated orally once a day for five days, and model of brain injury was made by dropping weight method. RESULT: RTP reduced water content and malondialdehyde (MDA) levels, and increased total SOD activity and Na+-K+ ATPase activity after injuried. CONCLUSION: The polysaccharides may be one of the effective comptents in Rheum tanguticum, showing significant neuroprotective effects.

Animals↗
PubMed2002

Fullerenes as a tert-butylperoxy radical trap, metal catalyzed reaction of tert-butyl hydroperoxide with fullerenes, and formation of the first fullerene mixed peroxides C(60)(O)(OO(t)Bu)(4) and C(70)(OO(Bu)(10).

tert-Butylperoxy radicals generated by TBHP and Ru(PPh3)3Cl2 or other catalysts adds to C60 and C70 to form stable multiadducts, C60(O)(OOtBu)4 and C70(OOtBu)10. The four tert-butylperoxy groups in the C60 mixed peroxide are located around a pentagon, and the epoxy O occupies the remaining 6,6-bond connected to the same pentagon. The C70 decaadduct shows an unprecedented C2 symmetry with the 10 tert-butylperoxy groups added around the central part of C70 by consecutive 1,4-addition. The compounds are fully characterized by spectroscopic data.

Fullerenes↗
PubMed2002

[Isolation, cultivation and identification of stem cells from cerebral cortex of mouse embryo].

OBJECTIVE: To isolate, cultivate and identify the neural stem cells from the cortex of embryo mouse in vitro for the further related research. METHODS: Cerebral hemisphere of mouse fetuses were taken out. Suspension of cerebral cells was made. Neural stem cells were identified by immunofluorescent cytochemistry to the primary culture. Neural stem cells were isolated and cultured in special culture medium using single-cell clone culture technique. After the stem cells were stably cultured successively for 20 generations, nestin, glial fibrillary acidic protein, beta-tublin, and galactosidase (Galc) were detected by indirect immunofluorescence cytochemistry. RESULTS: The stem cells isolated from the cerebral hemisphere of mouse embryo with positive expression of nestin could be passaged in vitro for at least 20 generations. Inoculated on the coverglass with poly-1-ornithine and cultured in medium containing serum, the stem cells were induced to differentiate. The cells differentiated from these stem cells showed green fluorescence by GFAP fluorescent staining, red fluorescence by beta-tublin fluorescent staining, or green fluorescence by Galc fluorescent staining. CONCLUSION: The stem cells from cortex of mouse embryo can be successfully isolated and cultured in vitro. The stem cells can be passaged in series and possessed the potential of multi-directional differentiation and express the specific antigens of neuron, astrocytes, and oligodendrocytes. Thus they can be used for further experimental study.

Animals↗
PubMed2002

Quantitative proteomics strategy involving the selection of peptides containing both cysteine and histidine from tryptic digests of cell lysates.

This paper describes a procedure for quantitative proteomics that selects peptides containing both cysteine and histidine residues from tryptic digests of cell lysates. Cysteine-containing peptides were selected first by covalent chromatography using thiol disulfide exchange. Following the release of cysteine-containing peptides from the covalent chromatography column with reductive cleavage, histidine-containing peptides were captured by passage through an immobilized metal affinity chromatography column loaded with copper. Quantification was achieved in a four-step process involving (i) differential labeling of control and experimental samples with isotopically differing forms of succinic anhydride, (ii) mixing the two globally labeled samples, (iii) fractionating the labeled peptides by reversed-phase liquid chromatography, and (iv) determining the isotope ratio in individual peptides by mass spectrometry. The results of these studies indicate that by selecting peptides containing both cysteine and histidine, the complexity of protein digests could be substantially reduced. Up-regulated proteins from plasmid bearing Escherichia coli that had been induced with isopropyl beta-thiogalacto-pyranoside were identified and quantified by the global internal standard technology (GIST) described above. Database searches were greatly simplified because the number of possible peptide candidates was reduced more than 95%.

Amino Acid Sequence↗
PubMed2002

[Neuronavigator-guided microsurgery for resection of brain tumors].

OBJECTIVE: To study locating accuracy for the brain tumors and their peri-structures by the neuronavigator and elucidate the microsurgical effects. METHODS: 65 patients with intracranial tumors were microsurgically treated by the application of Stealth Station and Vector Vision system. The treatment effects were summarized and the neuronavigational accuracy was discussed. RESULTS: After mean fiducial error (MFE) and sustained accuracy (SA) were satisfied. Total tumor removal was achieved in 63 cases (97.0%), subtotal removal in 2 cases (3.0%). The neurological functions were improved in 56 cases (86.2%), unchanged obviously in 9 cases (13.8%). No case deteriorated and died in the group. CONCLUSIONS: Navigation systems are reliable and accurate in making microneurosurgical plans for brain tumors. And they can provide tracing of the tumor in the operation and guide the operator's manipulation. The techniques, which help total removal of the tumors and reduce the postoperative complications, are very useful in guarantee operation effects.

Adult↗
PubMed2002

[Effects of recombinant human bone morphogenic protein-2 and hyaluronic acid on invasion of brain glioma in vivo].

OBJECTIVE: To investigate the effects of recombinant human bone morphogenic protein-2 (rhBMP-2) and hyaluronic acid (HA) on the invasion and metastasis of rat brain glioma in vivo. METHODS: C6 rat glioma cells were transfected with the plasmid vector named pEGFP-N3 which contained an enhanced green fluorescent protein (EGFP) gene. The stable cell clones which expressed EGFP protein were stereotactically injected into the brain parenchyma of SD rats in order to establish a xenotransplanted tumor model. After rhBMP-2 and HA were administered in the xenotransplanted tumor model at different dosages, their effects on glioma invasion and metastasis were observed by pathology, flow cytometry fluoresclnec, and electronmicvoscopy. RESULTS: EGFP-transfected C6 glioma cells gave off green fluorescence in vivo and in vitro. Area with tumor and area without tumor could be easily distinguished by fluorescence microscopy. Even distant micrometastasis and invasion at single-cell level could be detected. 10 microliter rhBMP-2 of the concentration of 5 microgram/ml inhibited C6 tumor invasion, while 10 microliter hyaluronic acid of the concentration of 100 microgram/ml evidently promoted the tumor invasion. CONCLUSION: EGFP-transfected C6 cells can be transplanted into rats' brain so as to establish an excellent experimental animal model in the research on invasion and metastasis of brain glioma in vivo. RhBMP-2 inhibits tumor invasion, while HA evidently promotes its invasion.

Animals↗
PubMed2002

Experiment and observation on invasion of brain glioma in vivo.

Research on invasion and metastasis of glioma in vivo was performed by implanting C6 glioma cells transfected with enhanced green fluorescent protein (EGFP) gene into the brain of SD rats. Firstly, C6 glioma cells were transfected with a plasmid vector (pEGFP-N3) containing the EGFP gene. Stable EGFP-expressing clones were isolated and examination for these cells by flow cytometry and electron microscope was done. Secondly, EGFP-expressing cells were stereotactically injected into the brain parenchyma of SD rats to establish xenotransplanted tumor. Four weeks later rats were killed and continuous brain sections were examined using fluorescence microscopy after adjacent sections were examined by immunohistochemistry or routine hematoxylin and eosin staining for the visualization and detection of tumor cell invasion. Xenotransplanted tumor was primarily cultured to determine the storage of EGFP gene in vivo. The results showed that EGFP-transfected C6 glioma cells maintained stable high-level EGFP expression in the central nervous system during their growth in vivo. EGFP fluorescence clearly demarcated the primary tumor margin and readily allowed for the visualization of distant micrometastasis and invasion on the single-cell level. Small locally invasive foci, including those immediately adjacent to the leading invasive edge of the tumor, were virtually undetectable by routine hematoxylin and eosin staining and immunohistochemistry. These results suggested that EGFP-transfected C6 cells can be visualized by fluorescence microscopy after intracranial implantation. This model is an excellent experimental animal model in research on invasion and metastasis of brain glioma in vivo.

Animals↗
PubMed2002

Innate immunity in host-microbial interactions: beyond B27 in the spondyloarthropathies.

The spondyloarthropathies are diseases influenced by genetic predisposition and, to a varying extent, infectious triggers. A causal role for bacterial infections is most clear for reactive arthritis. Recent insights into arthritogenic components of bacteria may set the stage for a better understanding of disease pathogenesis, the role of heat shock proteins in antigen processing and immune activation, and the adjuvant effect of CpG-DNA. Recent developments in the area of innate immunity broaden current concepts of genetically defined factors in host-pathogen interactions. In particular, the biology of toll-like receptors as important elements in the innate immune response to pathogens is being defined. These factors in innate immunity may have important implications for sequelae of infections, such as reactive arthritis.

Animals↗
PubMed2002

Brain metastasis: experience of the Xi-Jing hospital.

BACKGROUND: The management of metastatic brain tumors is an important issue in patients with malignant tumors or cancer. The authors summarize the results of patients with brain metastases treated at the Xi-Jing Hospital during a 10-year period, in order to assess the best modality of treatment for patients with brain metastases. METHODS: Between 1990 and 2000, 463 patients with brain-metastatic tumors were treated at the Xi-Jing Hospital of the Fourth Military Medical University, Xian, China. In most patients, the pathologic diagnosis of primary cancer was obtained before they were referred for their brain metastasis. There were 34 (8.42%) cases with an unknown primary cancer site at the time of initial presentation. Patients were grouped according to treatment methods, which included neurosurgical craniotomy (NS; 130 patients), whole-brain radiotherapy (WBRT; 120 patients). Linac XKnife radiosurgery (RS; 130 patients) and Linac XKnife radiosurgery plus WBRT (RT; 83 cases). Survival was measured from the time of treatment and was analyzed by the Kaplan-Meier product-limit method and then plotted. Differences between curves were evaluated using the log-rank test. Multivariate factors associated with survival were analyzed using the Cox proportional hazards model. RESULTS: The survival time was 68.4 +/- 7.20 weeks after NS, 51.3 +/- 5.04 weeks after WBRT, 67.9 +/- 3.68 weeks after RS and 89.7 +/- 4.50 weeks after RT. The presence of active systemic cancer in a larger number of metastatic tumors was associated with a poor survival (p = 0.0003 and 0.0000). The female patients showed better survival rates over the male ones (p = 0.0000). Patients treated with RT had a better survival than those treated with NS, WBRT and RS (p = 0.0048, 0.0000 and 0.1222, respectively), although the latter did not show statistical significance. CONCLUSIONS: RS was an effective modality for patients with brain metastases, and if combined with WBRT, survival was better. Progression of systemic cancer and the number of metastatic tumors were the most significant factors for a poor survival after treatment of the brain metastases.

Adult↗
PubMed2002

Development of a rat C6 brain tumor model.

OBJECTIVE: To establish rat C6 brain-tumor models and find a simple reliable index to judge tumor volume. METHODS: C6 cell suspension (10 microl) containing 10 g/L agarose and 1 x 10(6) cells was injected into the right caudate nucleus of the rat brain by a stereotaxic method. After implantation, rats were observed and given MRI scans. Rats were perfused with paraformaldehyde trans-aorta at the 10th, 15th, 20th and 25th day and before natural death. All brains, lungs, spinal cords and tumors were sectioned and inspected. Tumor-containing samples were prepared histologically by hematoxylin and eosin (HE) stains. RESULTS: Fifty implanted rats had 100% yield of intracerebral growth, with distant metastasis of 0% to 4%. CONCLUSION: A rat C6 brain-tumor model was successfully established. Rat survival time is correlated with tumor volume and may be useful as an index of tumor size.

Animals↗
PubMed2000

Content change of neurofilament protein subunits in experimental brain diffuse axonal injury by lateral head rotation.

OBJECTIVE: To explore the content change of neurofilament (NF) protein subunits in the experimental brain diffuse axonal injury (DAI) by lateral head rotation. METHODS: Twenty-four Sprague Dawley (SD) rats were equally divided into three injury groups (2 h, 12 h, and 24 h post injury) and one control group. The models of DAI were made in the injury groups by lateral head rotation. Western blotting technique was used to measure the content of NF68 (a kind of NF protein subunit) in the brainstem tissues among all the injured and control rats. The NF68 immunohistochemical staining was used in another six SD rats in order to observe the morphological changes in DAI. RESULTS: The NF68 content in the brainstem tended to decrease at 2 h post injury, decreased significantly at 12 h and continued its decrease at 24 h. NF56 and NF52, as the breakdown products of NF68, had a tendency to increase at 2-12 h after the injury, and amounted to a significantly higher level at 24 h. Microscopically, there were a lot of swelling neuronal axons in the ventral part of the medullar oblongata at 2 h after the injury. Some axons were disconnected, and axonal retraction balls formed on their proximal end. CONCLUSIONS: There is an occurrence of phosphorolysis within the brainstem in DAI by lateral head rotation. These reactions cause the breakdown of NF68, which results in the decrease of NF68 in content. It suggests that the breakdown of neurofilament protein subunits is an important reason for structur al destroy of neurofilaments in DAI.

Journal Article↗
PubMed1999

Emergency treatment of craniocerebral firearm wounds.

OBJECTIVE: To improve the outcome of treatment in patients with craniocerebral firearm wound. METHODS: Prospectively and retrospectively reviewed a series of 93 patients presented to the Xi-Jing Hospital of Fourth Military Medical University with a diagnosis of craniocerebral firearm wound during a period of 27 years from July 1970 to July 1997. All the patients had acute craniocerebral firearm wound. Of these, it consisted of 81 males (87.1%) and 12 females (12.9%) ranging from 3 months to 58 years in age (median 24.6 years). The lesion included 16 tangential wounds, 58 tubular wounds and 19 through-and-through wounds. The cases were urgent and in serious and unstable condition. All the patients underwent surgical intervention and aggressive perioperative management in the neurosurgical intensive care, including resuscitative protocols. RESULTS: After emergency treatment and operation, 9 cases died (9.7%). Follow-up studies at three months postoperative showed that 56 cases (66.7%) had made good recovery. Rates of moderate disability, severe disability or vegetative state in this series were 19.0%, 10.7% and 3.6%, respectively. Long term follow-up studies (median 5.5 years) found that 42 (50.0%) were capable of resuming their occupation. CONCLUSIONS: Craniocerebral firearm wounds are often severe, needing urgent treatment for the patients. Timely, proper and thorough initial debridement are crucial for avoiding rapid neurological deterioration.

Journal Article↗
PubMed1999

Intra-axonal overloading of calcium ion in rat diffuse axonal injury and therapeutic effect of calcium antagonist.

OBJECTIVE: Exploring the intra-axonal overloading of calcium ion (Ca(2+)) in brain diffuse axonal injury (DAI) and the therapeutic effect of calcium antagonist(Nimotop) on DAI. METHODS: Fourteen SD rats were divided into injury group, treatment group and control group. The DAI model of rats was produced by using a head-instant-axial-rotation device. Tissues from the medulla oblongata of rats were taken 2-24 h post-injury and processed for electron microscopic observation by a cytochemical technique for calcium ion. RESULTS: In the injured rats there was evidence of local disruption of myelin sheath,lucent spaces between myelin sheath lamellae, separation of axolemma from the inner layer of myelin sheath, peripheral accumulation of organellae, intra-axonal formation of vacuoles and reduction of mitochondria. A large number of fine calcium deposits were seen on the affected myelin sheath. The severity of the myelin sheath lesion was related positively to the number of calcium deposits on it. In the later post-injury period the coarse calcium particles appeared within the damaged axon. Neuronal somas and microvascular endotheliums showed a lot of vacuoles and some fine calcium deposits. Many microvilli formed on the luminal aspect of endothelium. In the treatment group myelin sheath tended to be injured locally, and axoplasmic mitochondria were nearly normal in number, structure, and distribution. Few calcium deposits were found in axons. Vacuolization was obviously reduced in neuronal soma and endothelium. CONCLUSIONS: In DAI there exists an intra-axonal overloading of calcium ion, which is a key factor to the occurrence and development of DAI. Early use of Nimotop can alleviate DAI.

Journal Article↗
PubMed1999

Brain TXA(2) and PGI(2) levels in impact acceleration diffuse brain injury coupled with secondary insults.

OBJECTIVE: To study the changes of brain TXA(2) and PGI(2) levels in a new rodent model of impact acceleration diffuse brain injury with hypotention and hypoxia and the effect of diaspirin cross linked hemoglobin solution (DCLHb) on brain TXA(2) and PGI(2) levels. METHODS: Thirty-two male SD rats were randomized into sham, head injury alone, head injury with secondary insults and injury with insults followed by DCLHb administration groups. Animals were physiologically monitored throughout the experiment and the prostanoids were measured via radioimmunoassay (RIA). RESULTS: There were no changes in TXB(2) and 6-keto-PGF1alpha (stable metabolites of TXA(2) and PGI(2)) levels in injury alone group while TXB(2) level in secondary insults group elevated significantly and both TXB(2) and 6-keto-PGF1alpha levels in injury with insults followed by DCLHb administration augmented significantly in comparison with the corresponding value of sham at 4 h postimpact. CONCLUSIONS: The only increase in TXA(2) level in secondary insults rats suggests that there may be both thrombotic episodes and vasoconstriction leading to focal increase in micro-circulatory resistance which contributes to a decreased focal cerebral blood flow (CBF). And it is hypothesed that DCLHb may exert its protective properties through increasing PGI(2) production in injured brain by affecting CBF and cerebral perfusion pressure (CPP).

Journal Article↗
PubMed1998

Brain TXA(2) and PGI(2) levels after head injury with secondary insults.

OBJECTIVE: The brain TXA(2) and PGI(2) levels in a new rodent model of impact acceleration diffuse brain injury alone and with hypotention and hyperthermia in combination were observed to look into the relationship between TXA(2), PGI(2) levels and different types of head injury. METHODS: Thirty-two SD rats were randomized into sham, head injury alone, secondary insult alone and head injury with secondary insult groups. At 4 hours after injury or experiment, all the rats were decapitated and their brains were sampled for radioimmunoassay (RIA) measurement. RESULTS: Compared with that of sham group there were no changes in TXA(2) and PGI(2) levels in injury alone group while there was a significant augmentation in PGI(2) level in insult alone group. Both TXA(2) and PGI(2) level in injury with secondary insult group increased significantly in comparison with that of sham at 4 hours postimpact. CONCLUSIONS: PGI(2) providing energy and precursors to the injured tissue and producing some vasoactive arachidonic products, especially TXA(2), is closely connected to the severity of brain damage.

Journal Article↗
PubMed1998

Fluorescence-based Quantitative Analysis for mRNA in RT-PCR Process.

A DNA fragment that forms the template of a specific mRNA can be synthesized by reverse transcription PCR. In due number of cycle, the concentration of PCR product increases proportionally to that of the template cDNA, i.e., the corresponding mRNA in RT. Since the fluorescence quantum yield of ethidium bromide greatly increased when it was inserted into the DNA double helix, the extend of expression of mRNA can be calculated by determining the fluorescence intensity under selected excitation and emission wavelengths of PCR cDNA after a proper number of PCR cycle.

Journal Article↗