Biomedical subjects

Z Wu

Publications and source records attributed to Z Wu.

At least 163 records · Page 9Linked to original sources

PubMed2001

[Clinical application of three-dimensional spiral CT in the complex maxillofacial fractures].

OBJECTIVE: The aim of this study was to evaluate the clinical application of the three-dimensional spiral CT in the complex maxillofacial fractures. METHODS: A total of 26 patients with complex maxillofacial fractures were examined using spiral CT with the slice thickness of 3 to 5 mm. The surface shaded display (SSD) method was used for reconstruction of the three-dimensional (3D) images. The three-dimensional images of maxillofacial fractures were obtained by using various rotations. Before the three-dimensional images were reconstructed, the drawing and deleting way was used for these mandibular fractures. RESULTS: The method demonstrated clearly the three-dimensional anatomy and their relationships of the fractures; using the drawing and deleting way, location and move condition of mandibular fractures, especially condylar fractures, were showed clearly. CONCLUSION: The three-dimensional CT is important in evaluating complex maxillofacial fractures. It could be used to demonstrate clearly locations and move conditions of complex maxillofacial fractures and operative plans.

Adolescent↗

PubMed2001

[Bcl-2, p53 expression and Epstein-Barr virus infection in primary nasopharyngeal carcinoma].

OBJECTIVE: To observe bcl-2, p53 gene expression and Epstein-Barr virus (EBV) infection and their relationship with clinicopathologic factors in primary nasopharyngeal carcinoma (NPC). METHOD: p53, bcl-2 proteins were assayed with immunohistochemical technique and EBV were assayed with polymerase chain reaction in 54 cases of NPC and 13 cases of chronic inflammation of nasopharyngeal epithelium (CINE). RESULT: The expression of p53, bcl-2 proteins and EBV were found respectively in 1(7.7%), 3(23.1%) and 1(7.7%) of 13 CINEs, which were significantly lower than those in 54 NPCs with respectively 41(75.9%), 48(88.9%) and 47(87%) (P < 0.01). In 39 cases of 54(72.2%) NPCs, we could find simultaneous p53, bcl-2 expression and EBV infection, furthermore, p53 and bcl-2 expression were significantly positively correlated with each other (r = 0.78, P < 0.01). p53 gene expression was significantly correlated with cervical lymph node metastasis of NPCs (P < 0.01). The expression of p53 in stage II, III, IV (92.9%, 78.9% and 100% respectively) were significantly higher than that in stage I (38.5%) (P < 0.01). CONCLUSION: The expression of p53, bcl-2 gene and EBV infection are the useful factors in the diagnosis of NPC, the overexpression of p53 is related with the stage and cervical lymph node metastasis of NPC, all the three play important roles in the pathogenesis of nasopharyngeal carcinoma.

Adolescent↗

PubMed2001

[The influence of labyrinthectomy on the expression of NMDA R1 mRNA].

OBJECTIVE: To study the effect of labyrinthectomy on the expression of NMDAR1 (N-methyl-D-aspartate receptor subunit R1). METHOD: The in situ hybridization was used to observe the expression of NMDA R1mRNA post-unilateral labyrinthectomy and investigate its effect on vestibular compensation. RESULT: 20 h post-unilateral labyrinthectomy, the NMDA R1mRNA positive neurons in the medial vestibular nucleus increased significantly compared with the unlesioned side(P < 0.01). 40 h-6 d, the positive cells decreased gradually. 6 d post lesion, the positive neuron counts of the lesioned side had no significant difference compared with those of the un-lesioned side (P > 0.05). CONCLUSION: The changing trend of the expression of NMDA R1mRNA in the medial vestibular nucleus is related to the recovery of the vestibular static symptoms after unilateral labyrinthectomy. It is suggested that the modulation of the efficacy of the NMDA R1 play an important role in the compensation of the static symptoms.

Animals↗

PubMed2001

[Anatomy structures of nasal cavity and paranasal sinus on virtual endoscopy and coronal image].

OBJECTIVE: To evaluate normal and bony anatomy of nasal cavity and paranasal sinus on the spiral CT virtual endoscopy(VE) and coronal scanning image. METHOD: After patients were scanned on axial or coronal position by spiral CT, data were transferred to workstation. Structures such as ostium-meatal complex(OMC) were viewed by navigator software when threshold was changing. RESULT: Turbinates, meatus and ostium-meatal complex were better viewed by virtual endoscopy compared with by coronal scanning image. To some extent, bony anatomy was clearer. CONCLUSION: Virtual endoscopy is of value in realizing characteristics of nasal cavity and paranasal sinus anatomy.

Adolescent↗

PubMed2001

[Sequence analysis of RAN4 of a severe isolate of rice stripe virus in China].

RNA4 segment of a severe isolate of Rice stripe virus, isolated from Liaoning province and designated as PJ isolate, was amplified, cloned and sequenced. RNA4 of PJ isolate had 2157 nucleotide in length. When compared with RNA4 of T and M isolates of Japan and CX isolate of Yunnan province of China that had been previously reported, we found that these four isolates could be divided into two groups. PJ, T and M isolates shared 97.0% and 97.0%-97.5% identities in vORF4 and vcOFR4 at the nucleotide level, respectively and formed one group. The sequences in 5' and 3' terminal non-encoding region were completely identical among these three isolates. In this group, PJ isolate was more closely related to T isolate than to M isolate. The length of intergenic region(IR4) of PJ isolate was as same as that of T isolate, and had 93.0% sequence identity. However, PJ IR4 had an insertion of 19 bp in length compared with isolate M and had only 85.0% sequence identity. CX isolate belonged to another group, which shared only 94.0% and 92.5%-93.5% sequences identities in vORF4 and vcORF4 at the nucleotide level, respectively, even though there were not significant difference between these two group at the amino acid level. There was an insertion of 84 bp in length in the IR4 of CX isolate compared with PJ isolate and the sequence identity between two group reached to 72.0%-75.0%. Even though no base variation occurred in 5' terminal non-coding region, there was two bases substitution in 3' terminal non-coding region. These results showed that the isolates were grouped according to their geographical location. Additionally, highly consensus in 5' and 3' non-encoding region suggested that these regions played an very important role in transcription and replication of viral genome. Finally, the molecular epidemiology and gene functions of Rice stripe virus were discussed in this paper.

Amino Acid Sequence↗

PubMed2001

[Effect of 3'-UTR of EG I from Trichoderma reesei on its gene expression in Saccharomyces cerevisiae].

Several industrial yeast are developed as ideal expression hosts for the production of the commercially useful proteins. The expression levels in yeast cells of the heterologous proteins are affected by the regulation factors of the genes themselves. The full-length cDNA coding for EG I from Trichoderma reesei, the cellulose-degrading filamentous fungus, was expressed in Saccharomyces cerevisiae H158. EG I produced by the recombinant S. cerevisiae exhibits maximal activity at 50 degrees C-60 degrees C, pH 5.0. It was observed that removal of the 3'-untranslated region (3'-UTR) from EG I cDNA resulted in no active EG I produced by recombinant yeast. RT-PCR analysis indicated that unlike the yeast cells harboring full-length EG I cDNA, there was no detectable EG I mRNA in the yeast cells harboring EG I cDNA without 3'-UTR. The data suggested that 3'-UTR is important for the expression of EG I in Saccharomyces cerevisiae.

3' Untranslated Regions↗

PubMed2001

[Preliminary study on citral impaires the Aspergillus flavus membrane].

Compared with the normally growing A. flauas, the content as below was determined: the utilization ratio to protein and reducing sugar of hyphostroma poisened by citral, the activity of [Na+, K+]-ATPase capable of decomposition ATP, and the seepagevity ratio of electrolyte. In addition, the shape change in spore was observed via the scanning electron microscope (SEM) and the fast multi-channel micro-spectrophotomer (FMCM). The result above all suggested facts as following after it's poised by the citral in MIC. The surface of hyphostroma and spore turned into be porous and rough. The pass trace on spore shriveled and closed. The rate of conduct electricity increased by 52.8%. The utilization ratio to protein and reducing sugar respectively decreased 61.5% and 44.3%. The rate of spore's sprout dropped to 61.4%. The molecular structure of membrane was so distinctly changed that it lost the selective permeability. There was inhibition on hyphostroma growth and spore sprout.

Absorption↗

PubMed2001

[Studies on the hydroxyl free radical-scavenging effect of combined selenium and germanium].

The effect of selenium, carboxyethyl-germanium sesquioxide (Ge-132) and the combination of selenium and Ge-132 on the production of hydroxyl free radical in liver microsomes of rats treated with Fe2SO4-NADPH system was studied with electron spin resonance technique (ESR). The results showed that the production of hydroxyl free radical was decreased significantly by adding selenium, Ge-132 and combined selenium and Ge-132, indicating a direct scavenging effect on hydroxyl free radical. It was also observed a enhanced scavenging effect at the low concentration of combined selenium and Ge-132.

Animals↗

PubMed2001

A case of Erdheim-Chester disease with bilateral orbital involvement.

PURPOSE: To describe a case of Erdheim-Chester disease with bilateral orbital involvement. METHODS: A 43-year-old female with bilateral proptosis was presented. Its clinical features, image findings, pathological character and therapeutic effect were evaluated. RESULTS: CT demonstrated bilateral, diffuse orbital mass. Histopathologic assessment revealed a diffuse xanthogranulomatous process with clusters of lipidladen histocytes. Numerous Touton giant cells were scattered throughout the lesion. Renal and heart failure happened during a 6-year follow-up period. Long bones roentgenogram demonstrated diffuse symmetrical sclerosis with extensive, lytic lesions. Systemic administration of corticosteroids, chemotherapy, immunoglobulin and traditional Chinese medicine showed good therapeutic result. CONCLUSIONS: An administration of systemic corticosteroids, chemotherapy, immunoglobin and traditional Chinese medicine can control Erdheim-Chester disease. Further exploration of its pathogenesis and collection of useful clinical data are required.

Adult↗

PubMed2001

[Application of fingerprint analysis and computer pattern interpretation in identification and quality evaluation of traditional Chinese medicines].

The fingerprint analysis technique used in the quality control of TCM through identifying charactreristics and evaluating stability is set up with the rapid development of instrument analyses and computer pattern interpretation. There are many kinds of methods for establishment of fingerpirnt of TCM mainly including chromatography, spectroscopic method, x-ray diffraction and molecular biological technique. The methods of computer pattern interpretation in fingerprint of TCM includes fuzzy information analysis, artificial neural networks and gray relational grade cluster.

China↗

PubMed2001

[Analysis of essential oil from Artemisia annul L. by extraction of different methods].

Essential oils from Artemisia annul L. were extracted with CO2 supercritical fluid and steam distilation. The essential oils were analyzed and contrasted by GC-MS. 114 components were identified by computer index. The rate of total components by supercritical CO2 fluid extraction and steam distillation were 81.24% and 85.75% respectively. Some of them such as diphenylene-Methane, Phenyl-1-naphthylamine were discovered from the plant for the first time.

1-Naphthylamine↗

PubMed2001

[Effects of retinoic acid on secretion of apolipoproteins A I, A II, B100, C III and E by cultured HepG2 cells].

OBJECTIVE: This study inquired into the role of retinoic acid in lipoprotein metabolism. METHODS: We observed the effect of retinoic acid on the secretion of apolipoproteins A I, A II, C III, B100 and E by cultured HepG2 cells. The apolipoprotiens contents in culture media were measured by radioimmunodiffusion assay (RID) kits developed by our research laboratory. 20-fold lyophilizely condensed culture media were used for the assays. RESULTS: Retinoic acid increased the secretion of apoA I, B100, C III and A II, and it inhibited the secretion of apoE. The effect of retinoic acid was strengthened in a dose-dependent manner. When the concentration of retinoic acid in cultured media was 2 x 10(-4) mol/l, the secretion of apoA I, A II, B100 and C III increased by 14.3% (P < 0.01), 23.8% (P < 0.05), 16.1% (P < 0.01) and 47.6% (P < 0.01) respectively, and the secretion of apoE decreased by 37.2% (P < 0.01). CONCLUSION: These findings indicate that retinoic acid does not have a general effect on apolipoprotein secretion in HepG2 cells.

Apolipoprotein A-I↗

PubMed2001

[The experimental study of intratemporal facial nerve regeneration in chitin chamber].

OBJECTIVE: To investigate the feasibility of intratemporal facial nerve regeneration in a chitin chamber. METHODS: A left 6 mm intratemporal facial nerve gap was created in adult white rabbit, and a total of 48 animals were used. The proximal and distal stumps were bridged with chitin chamber (experimental group) and silicone chamber (control group). Regeneration of the nerve was assessed by gross observation, nerve electrophysiological test, histological examination and digital morphological analysis in both groups. RESULTS: 1. Three months after implantation, the proximal transected neural stump was connected with the distal stump in the chitin chamber. Five months after operation, the regenerated nerve exhibited a more nature fascicular organization and the chitin tubes were completely absorbed. 2. Nerve evoked potentials showed better conduction ability in the chitin chamber. There were no significant difference in electrophysiological indices between the two chamber groups. 3. Most of the regenerated nerve fibers were myelinated nerve fibers, and axons and myelins had similar histograms between the experimental and control groups. 4. Five months after operation, the mean percentage of recovery of the regenerated nerve fiber area, axonal area and axonal number were more than 71% in the experimental group. There was no significant difference between the control and experimental groups. CONCLUSION: These results suggested that intratemporal facial nerve could regenerate effectively within the chitin chamber in rabbits and such kind of chamber may be clinically useful.

Animals↗

PubMed2001

[Effect of p14ARF gene on cell growth of human laryngeal tumor cells and expression of endogenous p53 protein].

OBJECTIVE: To explore the inhibitory effect of p14ARF on the cell growth of laryngeal carcinoma and the expression on endogenous p53. METHODS: p14ARF cDNA was transferred to the cell line Hep-2 of squamous cell carcinoma of the larynx by gene transfer to study the cell cycles and the expression of endogenous wild type p53 using flow cytometry, polymerase chain reaction(PCR) and Western-Blotting. RESULTS: Expression of p14ARF significantly affected the Hep-2 cell growth. The clone-forming efficiency of the Hep-2 cells transferred with p14ARF was 57%, compared with empty vector pcDNA3. The number of 48 hours after transfer with p14ARF cDNA at both G0/G1 and G2/M was two fold as the control. The expression of endogenous wild type p53 was significantly enhanced. CONCLUSION: Expression of p14ARF can up-regulate the expression of endogenous wild type p53 and inhibit the Hep-2 cell growth of human laryngeal squamous cell carcinoma at both G0/G1 and G2/M.

Carcinoma, Squamous Cell↗

PubMed2001

[Influence of different treatment modalities on survival of patients with two -stage resection of unresectable hepatocellular carcinoma].

OBJECTIVE: To study the therapeutic results of hepatic resection for shrunk hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE) and hepatic artery ligation and chemoembolization (HALCE) in patients with unresectable HCC, and compare the influence of the above different treatment modalities on the prognosis. METHODS: Two hundred and four patients w ith pathologically proven HCC by two stage liver resection were classified into two groups: TACE group (n = 112) and HALEC group (n = 92). The patients in the TACE group received a total of 1-7 consecutive treatment courses (average, 2.4 +/- 1.2 courses). HALCE was done in 49 patients. HALCE alternating fractionated radiotherapy was employed in 7 patients and HALCE + targeting regional internal radiotherapy in 36. Shrunk tumors were surgically removed by two-stage operation in all the patients with unresectable HCC. Seven possible factors influencing the results of two-stage resection of HCC were studied. RESULTS: All the patients were followed up to June, 1999. The 1-, 3-, 5-, and 7-year survival rates were 95.7%, 69.3%, 56.5% and 44.5% after the first TACE and HALCE, respectively and 88.5%, 64.9%, 51.9% and 38.3% after resection of the shrunk HCC, respectively. The 1-, 3-, 5- and 7-year survival rates were 94.1%, 64.7%, 51.2% and 40.8% respectively in the TACE group and 96.3%, 73.9%, 61.6% and 45.2% respectively in the HALCE group. There were no statistically differences between the survival rates in the TACE and HALCE groups. The extent of cirrhotic liver and percentage of tumor necrosis were of prognostic significance. In the TACE group, the extent of cirrhotic liver, the percentage of tumor necrosis and whether capsule of shrunk tumor was complete or in complete were of prognostic significance. In the HALCE group, however, the 7 factors were not found to be statistically significant for the prognosis. CONCLUSIONS: Sequential resection should be done after cytoreduction of tumor for the patients with unresectable HCC, which might improve their survival. The extent of cirrhotic liver and the percentage of tumor necrosis after TACE or HALCE are the major factors affecting the survival of patients with two-stage operation.

Carcinoma, Hepatocellular↗

PubMed2000

Ion channel behavior of supported bilayer lipid membranes on a glassy carbon electrode.

A new kind of solid substrate, a glassy carbon (GC) electrode, was selected to support lipid layer membranes. On the surface of the GC electrode, we made layers of didodecyldimethylammonium bromide (a synthetic lipid). From electrochemical impedance experiments, we demonstrated that the lipid layers on the GC electrode were bilayer lipid membranes. We studied the ion channel behavior of the supported bilayer lipid membrane. In the presence of perchlorate anions as the stimulus and ruthenium(II) complex cations as the marker ions, the lipid membrane channel was open and exhibited distinct channel current. The channel was in a closed state in the absence of perchlorate anions.

Carbon↗

PubMed2000

Pyrido[2,3-d]pyrimidin-7-one inhibitors of cyclin-dependent kinases.

The identification of 8-ethyl-2-phenylamino-8H-pyrido[2, 3-d]pyrimidin-7-one (1) as an inhibitor of Cdk4 led to the initiation of a program to evaluate related pyrido[2, 3-d]pyrimidin-7-ones for inhibition of cyclin-dependent kinases (Cdks). Analysis of more than 60 analogues has identified some clear SAR trends that may be exploited in the design of more potent Cdk inhibitors. The most potent Cdk4 inhibitors reported in this study inhibit Cdk4 with IC(50) = 0.004 microM ([ATP] = 25 microM). X-ray crystallographic analysis of representative compounds bound to the related kinase, Cdk2, reveals that they occupy the ATP binding site. Modest selectivity between Cdks is exhibited by some compounds, and Cdk4-selective inhibitors block pRb(+) cells in the G(1)-phase of the cell division cycle.

Adenosine Triphosphate↗

PubMed2000

Tryptophan- and dileucine-based endocytosis signals in the neonatal Fc receptor.

The neonatal Fc receptor, FcRn, transports immunoglobulin G across intestinal cells in suckling rats. FcRn enters these cells by endocytosis and is present on the apical and basolateral surfaces. We investigated the roles of aromatic amino acids and a dileucine motif in the cytoplasmic domain of rat FcRn. We expressed mutant FcRn in which alanine replaced Trp-311, Leu-322, and Leu-323, or Phe-340 in the inner medullary collecting duct cell line IMCD. Individual replacement of the aromatic amino acids or the dileucine motif only partially blocked endocytosis of (125)I-Fc, whereas uptake by FcRn containing alanine residues in place of both Trp-311 and the dileucine motif was reduced to the level obtained with the tailless receptor. Leu-314 was required for the function of the tryptophan-based endocytosis signal, and Asp-317 and Asp-318 were required for the dileucine-based signal. Nonvectorial delivery of newly synthesized FcRn to the two cell surfaces was unaffected by loss of the endocytosis signals. However, the steady-state distribution of endocytosis mutants was predominantly apical, unlike wild-type FcRn, which was predominantly basolateral. This shift appeared to arise because the loss of endocytosis signals inhibited apical to basolateral transcytosis of FcRn more than basolateral to apical transcytosis.

Amino Acid Motifs↗