Biomedical subjects

Z Fei

Publications and source records attributed to Z Fei.

At least 19 recordsLinked to original sources

PubMed2005

Secondary insults and outcomes in patients with hypertensive basal ganglia hemorrhage.

This study was designed to monitor secondary insults and their impact on outcomes of patients with hypertensive basal ganglia hemorrhage (HBGH). One hundred and twelve patients with HBGH (male 73, female 39) of age 42 +/- 8 years (range from 38 to 57 years) were studied. Operations included craniotomy or trephination drainage with urokinase thrombolysis. Conventional therapies were also given to the patients including the administration of mannitol, crystalloid and colloid solution. In the meantime, blood pressure (MAP), temperature (T) and SaO2 and other parameters were recorded in the intensive care unit. The ICP values were recorded, and the early clinical outcome was assessed upon discharge according to Glasgow Outcome Scale. Cerebral Perfusion Pressure was calculated as CPP = MAP-MICP. Outcomes in the group without secondary insults were better than that in the group with secondary insults (P < 0.01). No unfavorable outcomes were found in the 59 cases managed by ultra-early surgery whereas 36.1% of the cases operated after 6 hours of onset had unfavorable outcomes. It is concluded that the high incident rate of secondary insults in HICH patients influences outcome. Ultra-early surgery may also contribute to improved quality of survival.

Adult↗

PubMed2001

[Research of cloning, expression of human endostatin gene and its inhibition effects to the glioma in vivo].

OBJECTIVE: To clone human endostatin gene, detect its biological activities of endostatin protein and use it to cure human SHG44 gliomas of nude mice in vivo. METHODS: The mRNA from the human liver tissue was extracted. And the functional fragment of endostatin gene was amplified by RT-PCR. It was cloned into pUC19 and sequenced according to Dye primer sequencing kit. The non-fusion expression vector pDH-endo was constructed. The recombinant human endostatin gene was expressed in DH5alphaat the condition of temperature induction. The protein activities were tested by Chicken Chorio-Allantoic Membrane (CAM) assay and endothelial cell proliferation inhibitory assay. Endostatin protein was applied to the nude mice through hypodermic injection in order to cure the SHG44 glioma. RESULTS: The acquired endostatin gene is 551 bp, its sequence is correct and the expressed protein is 20 kDa. The protein possesses the anti-angiogenesis activity. Hypodermic injection of endostatin at the dose of 5 mg/kg/d, 10 mg/kg/d or 20 mg/kg/d can inhibit the human glioma angiogenesis and tumor growth(the inhibition rate of the tumor are seperately 34.5%, 76.1% and 80.2%). CONCLUSION: The cloning, expression and preliminary application of human endostatin protein lay the foundation for the antiangiogenesis therapy of glioma and the other solid tumors.

Angiogenesis Inhibitors↗

PubMed2001

Simian virus 40 large tumor antigen forms specific complexes with p53 and pRb in human brain tumors.

OBJECTIVE: To study the role of simian virus 40 (SV40) early region gene coding product large tumor antigen (Tag) expression and the interaction between Tag and tumor suppressors p53 and pRb in human brain tumorigenesis. METHODS: Tag was investigated by immunoprecipitation followed by silver staining and Western blot in 65 cases of human brain tumors and 8 cases of normal brain tissues. Tag-p53 and Tag-pRb complexes were screened in 18 and 15 Tag positive tumor tissues, respectively. RESULTS: Tag was found in all 8 ependymomas and 2 choroid plexus papillomas, 90% of pituitary adenomas (9/10), 73% of astrocytomas (11/15), 70% of meningiomas (7/10), 50% of glioblastomas multiforme (4/8), 33% of medulloblastomas (2/6). 5 oligodendrogliomas, 1 pineocytoma, and 8 normal brain tissues were negative for Tag. Tag-p53 complex was detected in all 18 Tag positive tumors. Tag-pRb complex was found in all 15 Tag positive tumors. CONCLUSION: SV40 Tag is expressed in human brain tumors and can form specific complexes with tumor suppressors p53 and pRb. The inactivation of p53 and pRb due to the formation of Tag-p53 and Tag-pRb complexes may be an important mechanism in the etiopathogenesis of human brain tumors.

Animals↗

PubMed2001

[Removal of large acoustic neuroma via suboccipito-retrosigmoid approach with microsurgical technique].

OBJECTIVE: To probe the treatment effects of large acoustic neuroma (LAN) via a suboccipito-retrosigmoid microsurgical operation. METHODS: 216 patients with LAN in the cerebellar pons angle were confirmed by CT or MRI in our department. Each tumor (diameter > or = 31 mm) was removed via a suboccipito-retrosigmoid microsurgical approach. Treatment results were evaluated and the preoperative and postoperative function of the acoustic nerve or the facial nerve was compared separately. RESULTS: The tumors were totally removed in 172 patients(79.6%), subtotally removed in 33 (15.3%), and partially removed in 11 (5.1%). Anatomic preservation of the acoustic nerve was achieved in 27 patients (12.5%), and functional preservation in 9 patients (Grade A, 4.2%) at discharge. Anatomic preservation of the facial nerve was achieved in 178 patients (82.4%) and functional preservation in 94 (House Grade, Grade I - II, 52.8%) at discharge. Follow-up observation (Median: 3.9 years) of 187 patients revealed good recovery in 128 patients (68.4%), fair recovery in 44 (23.5%), and poor recovery in 15 (8.0%). Late recurrence was noted in those with poor recovery (10 patients, 5.4%) (cured by second treatment). CONCLUSIONS: It is a safe and effective way to remove LAN via suboccipito-retrosigmoid approach with microsurgical technique.

Adult↗

PubMed2000

Analysis of single nucleotide polymorphisms by primer extension and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

A method for typing single nucleotide polymorphisms (SNPs) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) is described, in which a mass-tagged dideoxynucleoside triphosphate is employed in a primer extension reaction in place of an unmodified dideoxynucleoside triphosphate (ddNTP). The increased mass difference due to the presence of the mass-tag greatly facilitates the accurate identification of the added nucleotide, and is particularly useful for typing heterozygous samples. Twenty commercially available mass-tagged dideoxynucleoside triphosphates were screened for amenability to incorporation by AmpliTaq FS and ThermoSequenase DNA polymerases in single nucleotide primer extension (SNuPE) reactions. Several sample preparation and purification methods were also examined and compared. Float dialysis was found to be a simple, versatile, and effective method for purification of the extension products. High specificity and sensitivity were obtained, and all six possible biallelic SNP heterozygotes were determined accurately using a 44-mer synthetic oligonucleotide target DNA as a model system. Further validation of the method was demonstrated in the analysis of five single-base mutations in exon IV of the human tyrosinase gene. Single nucleotide variations within 182-bp PCR amplicons amplified from three plasmid and three human genomic DNA samples were genotyped at five variable positions, with results in 100% concordance with conventional sequencing. Genotypes were determined accurately at five sequence-tagged sites (STSs).

Base Sequence↗

PubMed2000

Expression and significance of urokinase type plasminogen activator gene in human brain gliomas.

BACKGROUND AND OBJECTIVES: Urokinase type plasminogen activator (uPA) regulates a variety of processes involved in tissue morphogenesis, cell differentiation, migration and invasion. We analyzed the available informations to better interpret the pathogenetic relationship between uPA activity and the malignant biological behavior of human brain gliomas. METHODS: We retrospectively studied the presence and distribution of uPA in human brain gliomas by Northern blot hybridization and immunohistochemical methods in 43 cases of brain gliomas and 5 cases of normal brain tissues. RESULTS: All tissues expressed 2.5 kb transcripts of uPA mRNA. The uPA mRNA levels were significantly higher in high-grade gliomas than in low-grade gliomas and normal brain tissues (P < 0.01). Levels of uPA mRNA expression in tumor tissues with recurrence in 18 months postoperatively and survival period less than 3 years were significantly higher than counterparts (P < 0.01). The distribution of uPA protein in the immunoreactivity was mainly in tumor cells and microvascular endothelial cells of glioblastomas and anaplastic astrocytomas, localizing at cytoplasms, especially near sites of vascular proliferation and at the leading edges of tumors. CONCLUSIONS: High expression of uPA gene is associated with the malignant progression of gliomas and demonstrates a high level of correlation with the recurrence and invasive behaviors of high grade gliomas.

Adolescent↗

PubMed2000

Expression and localisation of urokinase-type plasminogen activator gene in gliomas.

Urokinase-type plasminogen activator (uPA) activity is related to the malignant biological behaviour of tumours. In the present study, we examined the presence and distribution of uPA in human gliomas. The amounts of uPA were measured by Northern blotting hybridisation and immunohistochemistry in 43 gliomas and five normal brain specimens. Their relation to the clinical history was comprehensively analysed. All tissues expressed 2.5 kb transcripts of uPA mRNA. The uPA mRNA levels were significantly higher in high grade gliomas than they were in low grade gliomas and normal brain tissue (P < 0.01). Levels of uPA mRNA expression in tumour tissues with recurrence within 18 months postoperatively and survival less than 3 years were significantly higher than counterparts (P < 0.01). The uPA mRNA was also expressed in tumour cells near necrotic areas. The uPA protein expression was consistent with the uPA mRNA expression. The distribution of uPA protein immunoreactivity was mainly in tumour cells and microvascular endothelial cells of glioblastomas and anaplastic astrocytomas, localising in the cytoplasm, especially at sites of vascular proliferation and at the leading edges of tumours. These results suggest that expression of the uPA gene is associated with the malignant progression of gliomas and may play an important role in the recurrence and invasive behaviors of higher grade gliomas.

Adolescent↗

PubMed2000

[Rhubarb extracts in treating complications of severe cerebral injury].

OBJECTIVE: To investigate the therapeutic effects of the Chinese medicinal herb, Rhubarb, on severe brain injury. METHODS: Rhubarb extracts in ethyl alcohol and water were used to treat 20 patients with severe cerebral injury complicated by hyperthermia, renal failure, hemorrhage in the upper digestive tract, and increased intracranial pressure. Vital signs, variations of Glasgow coma scale (GCS) and intracranial pressure (ICP) of the patients were observed. The degree of hemorrhage in the digestive tract and the change in creatinine value were also observed. Other 20 patients served as controls. RESULTS: The result of the treatment group was more marked than that of the control group. Three days after administration of the rhubarb extract, the body temperature decreased by 1.1 degrees C, ICP by 0.4 kPa (1 mm Hg = 0.1333 kPa) on average, and the incidence of hemorrhage in the digestive tract by 30%. The volume of hemorrhage of the digestive tract decreased by 700 +/- 250 ml, and the time for turning occult blood to negative by 10%. CONCLUSION: The Chinese medical herb, rhubarb, has multiple therapeutic effects on severe brain injury.

Adolescent↗

PubMed2000

Non-X-ray comprehensive measurement for accurate localization of sublabio-septo-sphenoidal approach.

OBJECTIVE: To use non-X-ray comprehensive measurement for accurate localization of sublabio-septo-sphenoidal approach for shortening operating duration, decreasing hemorrhage, and increasing the success rate of operation. METHODS: Operations in 122 patients suffering from tumors in the sella turcica region used non-X-ray localizations including localization by the angle formed by the glalella, anterior nasal spina and anterior nasal spina-sella turcica; localization by the angle formed by the upper incisors, anterior nasal spina and anterior nasal spina-sella turcica; and localization by anatomical markers (determination of the midline by the nasoseptum and vomer; determination of the anterior wall of the sphenoidal sinus by the foramen of the sphenoidal sinus and vomer body; correction of the site by septum of the sphenoidal sinus; location of the center of saddle by the shape of the floor of the sella and determination of the approach direction by the damaged area in the sella turcica region) were comprehensively employed. Additionally, X-ray localization was used to correct its accuracy. RESULTS: Non-X-ray comprehensive localization was applied to 40 patients for determining the site and depth of the floor of the sella, and the preciseness of the measurement was confirmed with X-ray. Operating duration averages 2.2 hours. Non-X-ray localization was directly applied to 82 patients for comprehensively measuring the floor of the sella, and operations were successful. Operating duration averages 1.5 hours and blood transfusion averages 200 ml. No deaths and severe complications occurred. CONCLUSION: Non-X-ray comprehensive measurement can be directly applied for precisely localizing the floor of the sella.

Adenoma↗

PubMed2000

Expression and significance of urokinase-type plasminogen activator in human gliomas.

OBJECTIVE: To investigate the expression and clinical significance of urokinase type plasminogen activator (uPA) in human gliomas. METHODS: mRNA and protein expressions of uPA were examined by Northern blot hybridization and immunohistochemical method in 43 cases of gliomas and 5 cases of normal brain tissues and their relationship to clinical indexes was comprehensively analyzed. RESULTS: All tissues expressed the 2.5 kb transcript of uPA mRNA. The uPA mRNA level in high-grade gliomas was considerably higher than that in low-grade gliomas and normal brain tissues (P < 0.01). Levels of uPA mRNA expression in tumor tissues with recurrence during 18 postoperative months and a survival period less than 3 years, were significantly higher than counterparts (P < 0.01). uPA mRNA expression was strongly correlated with the microvessel quantity (MVQ) in gliomas (r = 0.56, P < 0.01). uPA protein was mainly distributed in tumor cells and endothelial cells of glioblastomas and anaplastic astrocytomas. CONCLUSION: Expression of uPA is associated with the malignant progression, invasion and angiogenesis of gliomas, and it may play a critical role in the recurrence and prognosis of gliomas.

Adolescent↗

PubMed2000

Angiostatin K(1-3) gene for treatment of human gliomas: an experimental study.

OBJECTIVE: To discuss the feasibility of gene therapy of human glioma by antiangiogenesis method. METHODS: Angiostatin K(1-3) cDNA with secretive signal was inserted into the polylinker sites of eukaryotic expression vector pcDNA3 to construct pcDNA-SAK(1-3). The vector was transfected into human SHG44 glioma cells by lipofectamine and the positive clone was screened by G418. The biological characteristics of glioma cells were examined by electronmicroscope and flow cytometry. The activity of angiostatin K(1-3) protein expressed by SHG44 cells was examined by the bovine micrangium endotheliocyte inhibition assay and immunofluorescence assay. When SHG44 cells were implanted into the strata subcutaneum of nude mice, tumor necrosis and micrangium were calculated immunohistochemically and electronmicroscopically for determining their characteristics and validity in gene therapy of human glioma by antiangiogenesis method. RESULTS: The eukaryotic expression vector pcDNA-SAK (1-3) was successfully constructed and transfected into glioma cells. The cells expressed angiostatin K(1-3) protein, and their tumorigenesis and angiogenesis in nude mice were greatly reduced. CONCLUSION: Angiostatin K(1-3) gene is feasible to treat human glioma. This experiment lays a foundation for gene therapy of the other solid tumors by antiangiogenesis method.

Angiostatins↗

PubMed2000

[Endoscopy-assisted neurosurgery for intracranial operation].

OBJECTIVE: To investigate the value of endoscope-assisted neurosurgery for intracranial operation. METHODS: 37 patients with intracranial lesions including tumors, aneurysms, cysts, hematomas, hydrocephalus and nerve-vessel compression syndrome were treated with this method. Their results were compared to those of microsurgery and macrosurgery. The items analyzed included exposure and protection of brain tissue and cranial nerves, views of operation field, length of procedure etc. RESULTS: 15 patients with tumors, showed a high rate of complete removal but less complications. The 6th nerves of CPA tumors operation were preserved. Six cases of nerve-vessel compression syndrome showed excellent therapeutic effects. In 8 cases of intraventricle lesions, using endoscope easily found tumor location and the cause of hydrocephalus. As to saccular diseases, endoscope was used to deal with the major location. In 4 cases of hematomas, less blot remained and the procedure shortened. Moreover the operation field was more clear and adequate on the expenses of no more complexity of the procedure. CONCLUSIONS: Endoscope-assisted microsurgery is helpful in intracranial operation. It might become a standard neuro-operation in near future.

Adolescent↗

PubMed1999

Stable-isotope-assisted MALDI-TOF mass spectrometry for accurate determination of nucleotide compositions of PCR products.

In parallel with a large-scale sequencing effort, the human genome project will need next-generation tools for accurate and efficient analyses of the enormous pool of DNA sequences. Such analyses are required for (a) validation of DNA sequences, (b) comparison of a parent (known) sequence with a related (unknown) sequence, and (c) characterization of sequence polymorphisms in various genes, especially those associated with genetically inherited human diseases. Here, we report a novel method that combines stable isotope 13C/15N labeling of PCR products of the target sequences with analysis of the mass shifts by mass spectrometry (MS). The mass shift due to the labeling of a single type of nucleotide (i.e., A, T, G, or C) reveals the number of that type of nucleotide in a given DNA fragment. Using this technique, we have accurately determined nucleotide compositions of DNA fragments. The method has also been applied to score a known single-nucleotide polymorphism (SNP). The comparisons of nucleotide compositions determined by our method among homologous sequences are useful in sequence validation, sequence comparison, and characterizations of sequence polymorphisms.

Cadherins↗

PubMed1999

Domain-specific interactions between the p185(neu) and epidermal growth factor receptor kinases determine differential signaling outcomes.

We expressed the epidermal growth factor receptor (EGFR) along with mutant p185(neu) proteins containing the rat transmembrane point mutation. The work concerned the study of the contributions made by various p185(neu) subdomains to signaling induced by a heterodimeric ErbB complex. Co-expression of full-length EGFR and oncogenic p185(neu) receptors resulted in an increased EGF-induced phosphotyrosine content of p185(neu), increased cell proliferation to limiting concentrations of EGF, and increases in both EGF-induced MAPK and phosphatidylinositol 3-kinase (PI 3-kinase) activation. Intracellular domain-deleted p185(neu) receptors (T691stop neu) were able to associate with full-length EGFR, but induced antagonistic effects on EGF-dependent EGF receptor down-regulation, cell proliferation, and activation of MAPK and PI 3-kinase pathways. Ectodomain-deleted p185(neu) proteins (TDelta5) were unable to physically associate with EGFR, and extracellular domain-deleted p185(neu) forms failed to augment activation of MAPK and PI 3-kinase in response to EGF. Association of EGFR with a carboxyl-terminally truncated p185(neu) mutant (TAPstop) form did not increase transforming efficiency and phosphotyrosine content of the TAPstop species, and proliferation of EGFR.TAPstop-co-expressing cells in response to EGF was similar to cells containing EGFR only. Thus, neither cooperative nor inhibitory effects were observed in cell lines co-expressing either TDelta5 or TAPstop mutant proteins. Unlike the formation of potent homodimer assemblies composed of oncogenic p185(neu), the induction of signaling from p185(neu).EGFR heteroreceptor assemblies requires the ectodomain for ligand-dependent physical association and intracellular domain contacts for efficient intermolecular kinase activation.

Animals↗

PubMed1999

Management of nonfunctioning pituitary adenomas with suprasellar extensions by transsphenoidal microsurgery.

BACKGROUND: We evaluated the feasibility and therapeutic effectiveness of transsphenoidal microsurgical removal of nonfunctioning pituitary adenomas with suprasellar extensions. The diagnostic modes, surgical technique, and outcome were reviewed in 208 patients with pituitary adenomas extending beyond the sella turcica who were treated by transsphenoidal microsurgery. All patients except three presented with significantly diminished visual acuity and visual field defects. METHODS: Diagnosis was confirmed by skull X-ray plain films, CT, or MRI scanning. Operations were performed via a transsphenoidal approach under microscope. A subarachnoid catheter was preoperatively inserted in the lumbar cistern, through which saline was slowly injected during operation to increase the intracranial pressure so as to move the suprasellar tumor into the operative field to aid the removal. RESULTS: In this series, gross total removal of an adenoma in 146 cases (70.2%) and subtotal removal in 50 cases (24.0%) was achieved; partial removal was carried out in the remaining 12 cases (5.8%) of fibrous or dumbbell-shaped adenomas. There were no deaths in this group. Follow-up review (median 3.8 years) in 187 patients revealed that 97.8% of those with preoperative diminished visual acuity had postoperative improvement; 2.2% had no change, and none deteriorated significantly. Among 181 patients with preoperative visual field defects, postoperative improvement was good in 169 (93.4%), and poor in 12 (6.6%). The major complications were diabetes insipidus and cerebrospinal fluid rhinorrhea, which occurred in 13.5% and 4.8% of patients, respectively. The tumors recurred in 12 patients (6.4%) who were considered to have a macroscopically complete removal at surgery. Continuing growth of residual tumors was found in 31 (16.6%) based on visual acuity decrease, visual field defects, and CT or MRI examination. Of the recurrent and residual tumors, 4, 9, 17, and 13 cases belonged to Grades A, B, C, and D, respectively. CONCLUSIONS: Comparison with transfrontal surgery suggests that these results are as good as those of transfrontal procedures and that the incidence of serious side effects is considerably lower. We consider that the microsurgical removal of pituitary tumors by the transsphenoidal approach is safe and effective even in very large or giant adenomas, since it allows rapid and adequate decompression of the optic nerves and chiasm.

Adenoma↗

PubMed1999

[Transsphenoidal microsurgical removal of suprasellar extension pituitary adenomas].

OBJECTIVE: To probe the diagnosis, transsphenoidal microsurgical technique and outcomes of patients with suprasellar extension pituitary adenomas (SEPA). METHODS: A total of 248 patients suffering from SEPA were diagnosed by CT or MRI scanning in our department. All adenomas had suprasellar extension (extension size: > 10 mm). The tumors were removed via sphenoidal approach under a microscope. RESULTS: The gross total removal of adenoma was achieved in 196 patients (79.0%), and subtotal removal in 41 patients (16.5%). Partial removal was carried out in the remaining 11 patients (4.4%) with fibrous or dumbbell-shaped adenomas. There were no deaths after surgery. Long-term follow-up observation (median: 3.5 years) in 227 patients revealed good recovery in 176 (77.5%) and late recurrence in 51 (22.5%). Those patients with tumor recurrence underwent reoperation, drug therapy and radiosurgery either alone or in combination. CONCLUSION: Except for fibrous and dumbbell-shaped ones, microsurgical technique via transsphenoidal approach is a safe and effective way to remove SEPA.

Adenoma↗

PubMed1999

Cloning and sequencing of the fragment of angiostatin K (1-3) gene.

OBJECTIVE: To secure anti-endotheliocyte hyperplasia functional fragment of human angiostatin K (1-3) gene. METHODS: As the template of leukocytotic cDNA, functional fragment of human angiostatin K (1-3) cDNA was amplified by PCR, cloned into the vector pGEM-3Zf, and sequenced according to Dye primer sequencing kit. RESULTS: The functional fragment of angiostatin K (1-3) cDNA (859 bp) was obtained by PCR and determined by sequencing. CONCLUSION: The angiostatin K (1-3) gene has been cloned. The gene is of great significance in tumor-antiangiogenesis therapy.

Angiogenesis Inhibitors↗

PubMed1998

MALDI-TOF mass spectrometric typing of single nucleotide polymorphisms with mass-tagged ddNTPs.

A matrix-assisted laser desorption/ionization time-of-flight mass spectrometry based method has recently been reported for the typing of single nucleotide polymorphisms using single nucleotide primer extension. This method is limited in some cases by the resolution of the mass determination, as the mass difference between nucleotides can be as little as 9 Da (the difference between A and T). A variation of this method is described here in which a mass-tagged dideoxynucleotide is employed in the primer extension reactions in place of the unmodified dideoxynucleotide. The increased mass difference due to the presence of the mass-tags substantially improves the accuracy and versatility of the procedure.

Dideoxynucleosides↗