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Biomedical subjects

W Li

Publications and source records attributed to W Li.

At least 613 records · Page 34Linked to original sources
PubMed1999

The adsorptive properties of hydroxyapatite to albumin, dextran and lipids.

Hydroxyapatite is widely utilized as a component in dental hygiene agents. The ability to adsorb and remove dental plaque adhering to tooth surfaces is recognized as an important property of hydroxyapatite particles. In this study, the adsorptive ability of hydroxyapatite was evaluated based on its adsorptive amount and adsorptive strength. The adsorptive amount was determined by measuring the weight of albumin, dextran and lipids adsorbing to hydroxyapatite. The adsorptive strength was determined by measuring the weights of albumin and dextran remaining adsorbed after rinsing. Similar procedures were performed in control experiments using calcium hydrogen phosphate dihydrate, alumina and sericite. The results showed that the weights of albumin and dextran adsorbed to hydroxyapatite were 1.4 +/- 0.13 and 1.6 +/- 0.30 times higher than that to calcium hydrogen phosphate dihydrate. The weight of lipids adsorbed to hydroxyapatite was much higher than that to alumina and sericite. The percentages of weight loss of albumin and dextran were 2.3 +/- 1.7% and 5.3 +/- 2.0% for hydroxyapatite and 27 +/- 6.8% and 19 +/- 11% for calcium hydrogen phosphate dihydrate after one rinse. It is concluded that hydroxyapatite is a better adsorbent than calcium hydrogen phosphate dihydrate, alumina and sericite with respect to adsorbing albumin, dextran and lipids.

Adsorption↗
PubMed1999

BUBR1 phosphorylation is regulated during mitotic checkpoint activation.

Eukaryotic cells have evolved a mechanism that delays the progression of mitosis until condensed chromosomes are properly positioned on the mitotic spindle. To understand the molecular basis of such monitoring mechanism in human cells, we have been studying genes that regulate the mitotic checkpoint. Our early studies have led to the cloning of a full-length cDNA encoding MAD3-like protein (also termed BUBR1/MAD3/SSK1). Dot blot analyses show that BUBR1 mRNA is expressed in tissues with a high mitotic index but not in differentiated tissues. Western blot analyses show that in asynchronous cells, BUBR1 protein primarily exhibits a molecular mass of 120 kDa, and its expression is detected in most cell lines examined. In addition, BUBR1 is present during various stages of the cell cycle. As cells enter later S and G2, BUBR1 levels are increased significantly. Nocodazole-arrested mitotic cells obtained by mechanical shake-off contain BUBR1 antigen with a slower mobility on denaturing SDS gels. Phosphatase treatment restores the slowly migrating band to the interphase state, indicating that the slow mobility of the BUBR1 antigen is attributable to phosphorylation. Furthermore, purified recombinant His6-BUBR1 is capable of autophosphorylation. Our studies indicate that BUBR1 phosphorylation status is regulated during spindle disruption. Considering its strong homology to BUB1 protein kinase, BUBR1 may also play an important role in mitotic checkpoint control by phosphorylation of a critical cellular component(s) of the mitotic checkpoint pathway.

Cell Cycle Proteins↗
PubMed1999

Ribavirin and quercetin synergistically downregulate signal transduction and are cytotoxic in human ovarian carcinoma cells.

Ribavirin, a nucleoside, well known as a broad-spectrum antiviral agent, is extensively used in the treatment of hepatitis C infections. Ribavirin inhibits IMP DH (EC 1.1.1.205) activity and reduces cellular GTP concentration. Quercetin, a plant flavonoid, exhibits antineoplastic activity and inhibits PI 4-kinase (EC 2.7.1.67) and PIP 5-kinase (EC 2.7.1.68) activity. Ribavirin and quercetin attack the cell cycle at the G1 and G1/S boundary, respectively. Because they act on different enzyme targets and arrest the cell cycle at different phases, we tested the hypothesis that ribavirin and quercetin might be synergistic in growth inhibition and cytotoxicity. Human myeloma 8226 and human ovarian carcinoma OVCAR-5 cells were studied because in these cells IMP DH activity increased 14- and 20-fold, respectively, and PI 4- and PIP 5-kinase activities were also elevated. In growth inhibition for ribavirin and quercetin in myeloma 8,226 cells IC50s were 40 and 70 microM, respectively. In OVCAR-5 cells in growth inhibition and clonogenic assays for ribavirin IC50 and LC50 of 35 and 23 microM, respectively, were observed. When quercetin was added 24 h after ribavirin, synergistic antiproliferative action was observed in both myeloma 8,226 and OVCAR-5 cells. Synergistic action was also obtained in OVCAR-5 cells in clonogenic assay when ribavirin was combined with quercetin in the sequence described above. The mechanism of action is provided, in part at least, by the synergistic reduction of signal transduction (IP3 concentration) by ribavirin and quercetin. Ribavirin and quercetin in combination might be of interest in the treatment of myeloma and ovarian carcinoma.

Antineoplastic Agents↗
PubMed1999

[Cerebral metastases in patients with epithelial ovarian carcinoma].

OBJECTIVE: To detect the rate of occurrence, the relevant factors, the diagnosis and treatment of cerebral metastases in patients with epithelial ovarian carcinoma. METHODS: The clinical data were analyzed in 4 cases of cerebral metastases from 132 cases of epithelial ovarian carcinoma after treatment between 1989-1997. RESULTS: The rate of cerebral metastases was 3%. The related factors were advanced stage, and tumor cells differentiation, but no related with the histologic type. More cases of cerebral metastasis were found because of the prolonged survival after cytoreductive surgery and systemic chemotherapy as well as the extraabdominal metastasis. CONCLUSIONS: Computed tomography and magnetic resonance imaging were the important diagnostic methods. Combined treatments including surgery, radiotherapy and chemotherapy can improve the patients status and prolong their lives.

Adenocarcinoma, Mucinous↗
PubMed1999

[A new approach for secondary deformities of unilateral cleft lip nose].

OBJECTIVE: The aim of this work was to correct the secondary deformities of unilateral cleft lip nose. METHODS: On the basis of patho-anatomical study and the comprehension on the cleft lip nose, a new approach to correct the secondary deformities of unilateral cleft lip nose was designed and used. During operation, an intranasal and marginal combining incision was made to explore the alar cartilages and to from a mucosal-cartilage flap in the nasal vestibule. After the deformity of septal cartilage and the abnormalities of the alar base on the cleft side were repaired, the total alar cartilage was repositioned and rotated with suspension and V-Y advancement to correct the nasal deformities. RESULTS: Since 1993, a total of 92 cases were treated by the above procedure and satisfactory results were obtained. CONCLUSION: The clinical applications showed that there were several advantages for this method, and good results can be gained by repositioning the total alar cartilage on the cleft side.

Abnormalities, Multiple↗
PubMed1999

Evaluation of cardiac beta-adrenergic receptor function in children by dobutamine stress echocardiography.

OBJECTIVE: To investigate the role of dobutamine stress echocardiography in evaluating cardiac beta-adrenergic receptor (beta-AR) function and responsiveness in children. METHODS: Left ventricular ejection fraction (EF), fractional shortening (FS), left ventricular end systolic volume index (ESVI), the ratio of systolic blood pressure and ESVI (SP/ESVI) were measured by dobutamine stress echocardiography (DSE) in 30 children with beta-AR hypersensitivity, 15 children with dilated cardiomyopathy and 30 normal children respectively. RESULTS: Before pharmacological stress, EF and FS were 0.72 and 0.39 respectively in beta-AR hypersensitivity group versus 0.70 and 0.35 respectively in control group. There was no difference of the indices between the two groups (P > 0.05). SP/ESVI was 0.76, higher than the value of 0.66 in control group (P < 0.05); EF, FS and SP/ESVI were 0.41, 0.15 and 0.10 respectively, which were significantly lower than those in control group. After dobutamine stress of 5 micrograms.kg-1.min-1 and 10 micrograms.kg-1.min-1, EF, FS and SP/ESVI were significantly increased in patients with beta-AR hypersensitivity and there were no changes in children with dilated cardiomyopathy compared with values of baseline. CONCLUSION: Cardiac beta-AR function and responsiveness can be evaluated by dobutamine stress echocardiography.

Adolescent↗
PubMed1999

[Alterations of FHIT gene and p16 gene in lung cancer and metastatic hilar lymph nodes].

OBJECTIVE: To investigate alterations of fragile histidine triad (FHIT) gene and p16 gene in lung cancer. METHODS: Forty-nine lung cancer specimens and 16 matched metastatic hilar lymph nodes of lung cancer patients were examined for abnormalities of p16 and FHIT genes by using RT-PCR and RT-PCR-SSCP. RESULTS: Thirty-two of 47(68.1%) samples of primary lung cancer and 15 of 16 (93.8%) samples of metastatic hilar lymph nodes exhibited loss of FHIT gene transcripts. In 14 of the 47 samples of primary lung cancer(29.8%), and 9 of 16 samples of metastatic hilar lymph nodes(56.3%), FHIT gene transcripts were deleted in exones 1-4. The deletion rate of p16 gene transcripts in exons 2-3 was 36.7% (18/49) in primary and 56.3% (9/16) in metastatic lymph nodes, respectively. The loss of p16 or FHIT expression did not correlate with sex, smoking, TNM stage, but was more frequently observed in poorly differentiated cancer. No mutation of FHIT and p16 cDNA was found by SSCP. CONCLUSIONS: Loss of FHIT and p16 gene transcript is frequent in lung cancer and may be an early event in lung carcinogenesis. Mutations may not be the major mechanisms of p16 and FHIT gene inactivation. Lung cancer with FHIT and p16 gene alterations have more malignant phenotype and behavior.

Acid Anhydride Hydrolases↗
PubMed1999

[Immune responses to recombinant expression plasmid encoding hepatitis C virus core antigen].

OBJECTIVE: To study the feasibility of DNA immunization with recombinant expression plasmid containing hepatitis C virus (HCV) core gene against HCV infection. METHODS: The recombinant plasmid containing HCV C gene was constructed and expressed transiently by using lipofectamine in the mouse SP2/0 cells. After appraisal and purification, these plasmid and control DNA were directly injected intramuscularly into BALB/c mice, HCV C specific antibody in the sera was checked with ELISA. Proliferative responses of spleen cells from experimental and control mice were determined by (3)H thymidine incorporation and cytotoxicity T lymphocyte (CTL) activity was measured by standard 4-h (51)Cr release assays. RESULTS: All immunized mice developed anti-HCV core antibodies and this antibody was dose and immune number dependent. Lymphoproliferative responses for HCV core antigen were higher in immunized mice than in control mice (P < 0.05), stimulation indices (SI) were 2.42 - 6.10. CTLs might induce approximately 63.13% lysis of pcDNA HCV C transfected SP2/0 target cells. CONCLUSION: It is suggested that HCV C gene immunization is a promising method of vaccination against HCV infection.

Animals↗
PubMed1999

[Frequent loss of fragile histidine triad gene transcripts in lung cancer].

OBJECTIVE: To investigate the significance of the fragile histidine triad (FHIT) gene in evaluation of early diagnosis and metastasis in lung cancer. METHODS: 47 lung cancer samples and 16 matched metastatic hilar lymph nodes of lung cancer patients were examined for abnormalities of the gene by using RT-PCR and RT-PCR-SSCP. RESULTS: 32 of 47 (68%) lung cancer samples and 15 of 16 metastatic hilar lymph nodes showed loss of FHIT gene transcripts (exon5-9 or exon1-4). RT-PCR-SSCP reveal no variants. CONCLUSIONS: These data indicate that loss of FHIT gene transcript is frequent in lung cancer and may be an early event in lung tumorigenesis and FRA3B may be involved in the development and progression of the lung cancer.

Acid Anhydride Hydrolases↗
PubMed1999

[The characteristics and management of shotgun wounds of the extremities].

OBJECTIVE: To discuss the characteristics, classification and the problem of management for shotgun wounds of the extremities. METHODS: 82 shotgun wounds of the extremities, classified according to the modified rule form Sherman and Ordog's, were treated by "incision and drainage" initially, and were closed in primary, delay and later phase. The fractures were fixed by plaster, external fixator, simple internal fixator or plate fixation. Vascular injury was repaired by suture end-to-end or autograft. The injured nerves were treated in the primary or later period. RESULTS: The rate of infection was the highest in the primary closed wound, and the healing time was the longest in the later closed wound. The rate of infection was much higher in the fracture fixed by plate than the others. The results of nerve recovery in primary repair were not significantly different (except 2 case infection) from those in the later repair. CONCLUSIONS: A significant difference was noted between shotgun wound and other wound. Removal of wadding, prevention of fascial compartment syndrome, repeat planned exploration of wound, proper wound closing, external fixation of fracture, vascular debridement before anastomosis and delayed nerves repair contribute to a successful outcome in patients with extremity shotgun wounds.

Adolescent↗
PubMed1999

[Can esophagogastric anastomosis prevent gastroesophageal reflux].

OBJECTIVE: To investigate the possible anti-reflux function of esophagogastric anastomosis in the patients after receiving resection of cardiac cancer. METHODS: One hundred and ninety-two patients were studied by video-assisted gastroscopy, manometry, 24-h pH esophageal monitoring, radioscintigraphy and scanning electron microscopy. RESULTS: Abnormalities were found in 90.2% of patients through endoscopy. Resting pressure in esophageal body was higher than that in normal controls, and in the stomach, lower. Twenty-four hour pH monitoring demonstrated that gastroesophageal reflux (GER) did not occur when the patients slept in semi-reclining position, and occurred in all patients when slept in supine position. Scintigraphic study showed that 2/3 of the patients had reflux, occurrence of which was not affected by the length of postoperative period. Scanning electron microscopic examination showed that degeneration, exfoliation of esophageal mucosal epithelial cell, and derangement of micro-fold and inflammatory oedema of cytomembrane may be directly caused by reflux. CONCLUSIONS: GER exists in the majority of the patients after esophagogastrectomy and esophagogastrostomy for cardiac cancer. The occurrence of GER is not affected by the length of postoperative period. Some detecting methods fail to show the existence of GER, and 24-h pH monitoring is the most reliable method for detecting GER. Sleep in semireclining position is an effective method of preventing GER in postoperative patients.

Adult↗
PubMed1999

[Transcatheter arterial embolization of renal carcinoma with absolute ethanol].

OBJECTIVE: To study transcatheter arterial embolization (TAE) of renal carcinoma using absolute ethanol so as to reduce bleeding for a higher resection rate, as a palliative treatment for advanced renal carcinoma. METHODS: Using Seldinger method, we treated 25 cases of renal carcinoma with transcatheter arterial embolization. RESULTS: The average bleeding of 25 cases during nephrectomy was 210ml after TAE. There was no mortality and serious complication. But there was pain and fever in most cases. CONCLUSIONS: TAE with absolute ethanol is an effective, safe and easy procedure. It could be used as an adjuvant therapy for renal carcinoma.

Adult↗
PubMed1999

[Comparison of different alimentary reconstructions after total gastrectomy for cancer].

OBJECTIVE: To study the optimum reconstruction after total gastrectomy for malignant disease, especially the necessity of gastric substitute and duodenal passage. METHODS: Among 75 patients having total gastrectomy, five kinds of reconstruction were used: Braun, modified Braun (mBraun) I, II, III, and antigrade jejunal interposition (AJI). Postoperative complaints, body weight, food intake, serum nutritional parameters, complete blood count, half-emptying time of the gastric substitute, PNI, Visick index were evaluated. RESULTS: As compared with Braun group, the mBraun I and II groups showed less reflux esophagitis, higher nutritional parameters and PNI, while the operation time was similar. As compared with mBraun I and II groups, mBraun III and AJI groups showed better body weight, higher nutritional parameters, and PNI. CONCLUSIONS: It is essential to construct a gastric substitute and maintain the alimentary tract flowing through the duodenum after total gastrectomy for cancer, and the AJI may be a better choice in the operation of gastrectomy.

Adult↗
PubMed1999

[The apoptosis and proliferation after photorefractive keratectomy].

OBJECTIVE: To search the correlation between the apoptosis and proliferation of keratocytes and investigate the influence of phototherapeutic keratectomy (PTK) and mechanical epithelial scrape (MES) on keratocyte apoptosis and proliferation. METHODS: Rabbit corneas received photorefractive keratectomy (PRK, -9.9 diopters, 6 mm diameter). Animals were evaluated subsequently up to 6 months after surgery by in vivo confocal microscopy. Corneas were prepared for H.E. staining, corneal cell apoptosis was evaluated by terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) to detect DNA fragmentation. RESULTS: Loss of keratocytes and keratocyte death were found anteriorly in the remaining stroma at 4h after PRK. Activated keratocytes observed by confocal microscopy repopulated within 1 month. A significant elevation of apoptosis was detected in keratocytes and epithelium at 4h, 3d, 1m after PRK. The level of keratocyte apoptosis was parallel to the loss of keratocytes at the early stage and was correlated with keratocyte proliferation in the later stage, PTK-PRK was associated with lower levels of central corneal apoptosis and activated keratocytes than MES-PRK. CONCLUSION: It is suggested that the loss of keratocytes and keratocyte apoptosis be correlated with keratocyte activation and proliferation, which may result in haze and regression after PRK, and PTK-PRK induce lower level of early keratocyte apoptosis and late keratocyte activation than MES-PRK.

Animals↗
PubMed1999

[Excimer laser photorefractive keratectomy for lower to moderate myopia: 5 year follow-up].

OBJECTIVE: To evaluate the long-term effectiveness and safety of photorefractive keratectomy (PRK) for patient with lower to moderate myopia. METHODS: 148 myopic eyes (-1.5 to -6.00 D) after PRK follow-up of more than 5 years were analyzed. RESULTS: Uncorrected visual acuity was >or= 1.0 in 136 eyes (91.9%), >or= 0.8 in 4 eyes (2.7%) and >or= 0.6 in 8 eyes (5.4%). The mean spherical equivalent change was from (-4.43 +/- 0.97) D to (-0.12 +/- 0.22) D, and the keratometric power (K value) was reduced from (43.81 +/- 1.10) D to (41.36 +/- 1.30) D in the 5 years of follow-up (P < 0.01). CONCLUSION: The long-term effectiveness of PRK for myopia (-1.5 to -6.00 D) is satisfactory.

Female↗
PubMed1999

[Long-term effect of extra-trabeculectomy in treatment of congenital glaucoma].

OBJECTIVE: To assess the long-term effect of extra-trabeculectomy in treatment of congenital glaucoma. METHODS: 29 patients (47 eyes) with congenital glaucoma having undergone extra-trabeculectomy were followed up for over 5 years. RESULTS: Success rates after single surgery were 70.2% at 6 months, 63.8% at 12 months, 57.5% at 18 months and 55.3% at 24 months. Re-elevation of intraocular pressure (IOP) all happened within 2 years after surgery. 14 eyes underwent second trabeculectomy, and 7 eyes (50.0%) were successful the total success rate was 70.2%. The naked visual acuity of 12 eyes (36.0%) among successful eyes was >or= 0.5. All the diseased eyes were myopic (-0.50 to -25.00 D). CONCLUSION: Follow-up of trabeculectomy should be emphasized within 2 years after surgery. Ametropic and anisometropic amblyopia should be corrected promptly after surgery.

Child, Preschool↗