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Biomedical subjects

X Liu

Publications and source records attributed to X Liu.

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

[Experimental study on effect of capping pulp with collagen].

OBJECTIVE: To investigate the function of collagen on reparative dentin formation, collagen was used as capping pulp material in the teeth of minipigs. METHODS: The histopathologic examinations and ultrastructures were observed after capping for 2 weeks, 4 weeks and 13 weeks. RESULTS: After 2 weeks, the reparative dental masses were formed and the stellative cells appeared. After 4 weeks, the reparative dental bridges were formed and the degenerative cells appeared in matrix. After 13 weeks, the complete, think and dense dental bridges were observed. CONCLUSIONS: It is suggested that capping with collagen can promote formation of reparative dentine without stimulation to the pulp and that collagen can be used for capping.

Animals↗
PubMed2001

[Endovascular stent-grafting of descending thoracic aortic lesions].

OBJECTIVE: To discuss the feasibility of endoluminal stent-grafting for descending thoracic aortic lesions. METHODS: 12 patients underwent stent-grafting of the thoracic aorta with Talent (11 patients) and Vanguard (1) device. Endovascular technique was used in 12 patients with descending thoracic aortic aneurysms (5 patients), Stanford B dissections (6), and pseudoaneurysm (1). 13 straight stent-grafts were inserted through 18-24 F theaths via a femoral arteriotomy under local (2 patients) or general (10) anesthesia. RESULTS: The procedure was technically successful in all patients without aneurysm rupture, paraplegia, and organs or limbs ischemia. There were 3 early endoleaks. Follow-up showed that 4 of 5 aortic aneurysms were excluded completely and one endoleak was changed into persistent. Four entries of 6 patients with stanford B dissection were excluded and 2 early endoleaks were sealed during one month after operation. Four false lumen were filled completely and 2 false lumen were filled partly by thrombosis. CONCLUSION: Descending thoracic aortic stent-grafting is a safe, highly successful and feasible alternative to conventional surgery. The long-term result remains unclear, especially that of the endovascular repair of Stanford B dissection.

Adult↗
PubMed2001

[Differential expression of cyclins D1, E and A in human breast diseases].

OBJECTIVE: To understand with greater clearness the effect of overexpression of cyclins gene and the potential implications of it for tumorgenesis in breast. METHODS: We assayed the expression of cyclins D1, E and A in different types of human breast diseases by immunohistochemical staining. RESULTS: Significant difference was seen among the malignant tumor, benign tumor and dysplasis(P < 0.001). The expressive intensity of above three kind of cyclins in malignant tumor was the highest, that in benign tumor was higher, and that in dysplasis was low. CONCLUSION: These data suggest that the expressive intensity of cyclins gene may serve as an indicator for malignant intensity of tumors. The expressive ratio difference of cyclins E and A between infiltrating ductal carcinoma and infiltrating lobular carcinoma may imply that there are different mechanisms involving the occurrence of different histological types of breast tumor.

Breast Neoplasms↗
PubMed2001

[Changes serum level of tumor specific growth factor and their clinical significance in mechanical trauma patients].

OBJECTIVE: To investigate the post-traumatic changes in the serum level of tumor specific growth factor (TSGF) and their relationship with Injury Severity Score and to inquire into the possible mechanism and clinical significance. METHODS: Fifty patients with mechanical trauma were eligible and included. According to the standard of Injury Severity Score (ISS), the patients were divided into there groups: mild degree group, (ISS < or = 16, n = 31) severe degree group (16 < ISS < 25, n = 13) extreme severe degree group (ISS > or = 25, n = 6). The blood samples of all patients were obtained within 24 hours, and those of 25 dynamically observed patients were obtained on days 3, 5, 7, 9 and 12. RESULTS: The serum level of TSGF was significantly higher in patients with trauma in different groups (P < 0.05). The dynamical observation showed that the index demonstrated curve changes with increase in early stage and decrease later. the climax of TSGF appeared on 7 day in all 3 groups. The TSGF serum levels in extremely severe degree and severe degree groups > mild degree group on days 5, 7, 9 and 12 day (P < 0.05). CONCLUSION: TSGF has relationship with the inflammatory response and recovery of trauma.

Adult↗
PubMed2001

[The effect of salvia miltiorrhiza and shengmai on inflammatory mediator and renal function of post-operative patients with obstructive jaundice].

OBJECTIVE: To investigate the effect of salvia miltiorrhiza and shengmai (SS) on inflammatory mediator and renal function in patients with obstructive jaundice (OJ). METHODS: This study included three groups: the OJ patients receiving SS for 6 days after operation (the SS group, n = 15); the OJ patients not receiving SS (the OJ group, n = 15); the patients with other hepato-biliary disorders (the Non-OJ group, n = 15). The levels of ET, LPs, TNF-alpha, IL-6, IL-8 and urine RBP, TFR, ALB were measured one day before operation and 1, 4, 7 days after operation. RESULTS: The SS group's LPs, TNF-alpha, IL-6, IL-8, ET, RBP, TFR and ALB levels were obviously lower on Day 7 after operation as compared with those on Day 1 after operation (P < 0.05). The urine RBP and ALB levels were significantly lower in the SS group than in the OJ group (P < 0.05). CONCLUSION: The post-operative use of salvia miltiorrhiza and shengmai for patients with obstructive jaundice may effectively decrease the postoperative levels of plasma LPs, ET, TNF-alpha, IL-6 and IL-8. At the same time, salvia miltiorrhiza and shengmai may protect renal function by inhibiting inflammatory mediator and improving blood dynamics.

Adult↗
PubMed2001

[The role of YIGSR and RGD peptides in regulating fenestrae of sinusoidal endothelial cells].

OBJECTIVE: To investigate the effects of Tye-Ile-Gly-Ser-Arg (YIGSR) and Arg-Gly-Asp (RGD) polypeptides on the fenestrae of the liver sinusoidal endothelial cells (SECs). METHODS: By in situ collagenase perfusion and two-step percoll gradient centrifugation, SECs were isolated from normal Wistar rats and cultured on collagen type I or laminin-coated coverslips. The population of SECs fenestrae and their diameters were observed using scanning electron microscopical technique; and the synthesis of collagen type IV in SECs was assessed by radio-immunoassay (RIA). RESULTS: The average number of fenestrae and their diameter in the SECs cultured on laminin-coated coverslips were significantly lower than those on collagen type I-coated coverslips. After the treatment with YIGSR pentapeptides (50 micrograms/ml) and RGD tripeptides (50 micrograms/ml) together for 48 hrs, the number and diameters of fenestrae in the SECs that grew on laminin-coated coverslips increased markedly. Meanwhile, the YIGSR and RGD peptides could significantly decrease the synthesis of collagen type IV in SECs that grew on laminin-coated coverslips. CONCLUSION: The results suggested that the YIGSR and RGD polypeptides may have an important role in regulating the morphology and function of SECs.

Animals↗
PubMed2001

[An experimental study on demineralization of several beverages on bovine enamel].

OBJECTIVE: The aim of this study is to investigate the demineralization effects of several beverages on bovine enamel. METHODS: The concentration of calcium and phosphate in these beverages were measured by using EL 312e Micro-Plate after the bovine enamel was exposed to beverages for a period of 7 days. RESULTS: The data indicated that almost all of these beverages could cause demineralization of bovine enamel, except mineral water, and the concentration of calcium and phosphate in these beverages changed after the bovine enamel was exposed to beverages. There were great significant differences in demineralization abilities among different beverages (P < 0.01). The concentration of calcium and phosphate in beverages also changed with time (P < 0.01). CONCLUSION: All these beverages, except mineral water have erosive effects on bovine enamel. Demineralization degree varied with kinds of beverages. The fruit juice has the highest erosive effect on the enamel, and the calcium milk has the lowest erosive effect on the bovine enamel, when comparing with other beverages.

Animals↗
PubMed2001

[Study on analysis of concentration of surfactant PS in injected-produced liquor used in ASP flooding with HPLC].

Ion exchanger and ODS bonded silica gel for HPLC packing were prepared. An HPLC method for the analysis of surfactant PS concentration in injected-produced liquor has been established to meet the need of ASP flooding developed in Gudao West Block of Shengli Oilfield, with a minimum detectable limit of 0.4 mg/L, a linear range of 50 mg/L-1,000 mg/L and recoveries of 95.7%-99.8%. This method has provided great technical support in a variety of fields to the design of the prescription for ASP flooding, the regulation of injection measurement, the quality control of products and the study on the mechanism of oil flooding etc.

English Abstract↗
PubMed2001

[Study of a mutation in connexin 26 gene associated with congenital sensorineural deafness].

OBJECTIVE: So far, at least 39 deafness gene loci have been mapped in human chromosome including the connexin 26 gene coding for a gap-junction protein. This gene is thought to be linked to hereditary non-syndromic sensorineural hearing loss. About 80% of cases of DFNB1 hereditary deafness carry a 30 mer G mutation of connexin 26. METHOD: To investigate this relationship, we obtained DNA samples from 15 cases with autosomal recessive and autosomal dominant forms of non-syndromic deafness. In addition, DNA samples were obtained from 252 unrelated subjects with sporadic hearing loss; parents of these subjects were symptom free. We analyzed the coding region for the connexin 26 gene for mutation using PCR-SSCP and sequence analysis and PCR-mediated site-directed mutagensis. RESULT: We detected 46 mutations with SSCP. The PCR products that of 5 cases mutations had similar abnormalities in their electrophoresis bands were sequenced. Results from 2 cases of families with hereditary hearing loss and 3 cases of sporadic hearing loss had a G-to-A transversion at nucleotide 79. In addition, 2 cases sporadic hearing loss with 251 delT and 233 delC were found, 35 delG was not detected in 46 cases abnormal PCR products using PSDM assay. CONCLUSION: High mutation rates were found in China deafness population of connexin 26 gene, but the mutation loci is different from those previously reported. Finding hot spot of connexin 26 gene mutation in China population is important for deafness etiologic diagnosis and affect genetic counseling.

Adolescent↗
PubMed2001

[Expression of two truncated enhancin gene from Helicoverpa armigera granulosis virus in E. coli and its preliminary bioassay].

The plasmids pET-30a-Ben and pET-30a-Den which included 1.7 kd and 2.2 kb fragments of 5'-terminal of HaGV enhancin gene were obtained by cutting recombinant plasmid pET-30a-En with Bal I and Dra I respectively. Two fragments were expressed in E. coli successfully and the products were named Ben and Den respectively. The enhancement, which Ben and Den enhance the infectivity of HaNPV and Bt in 3rd larvae of Helicoverpa armigera, was studied. The results indicated that there was increase of the mortality of 10.5%-26.5% and the LT50 decrease of 0.9 d causes by adding Ben, while Den could increase the mortality by 10.2%-33.0% and decrease the LT50 by 1.2 d-1.9 d. The preliminary bioassay on Bt against Helicoverpa armigera indicated the recombinant enhancin could increase the mortality of larvae by 20.7%-35.4%, Den by 16.7%-31.5%, Ben by 11.7%-27.4%.

Animals↗
PubMed2001

[Determination of DNA-DNA homology among Pseudomonas cocovenenans subsp. farinofermentans with microdilution plate hybridization method].

The DNA-DNA homologies among Pseudomonas cocovenenans subsp. farinofermentans and 11 species in genus Burkholderia were determined with microdilution plate hybridization method. The results showed: the homologies among P. cocovenenans subsp. farinofermentans, B. gladioli and B. cocovenenans were all over 75%. It was advised that these three species were synonym, and should be renamed as Burkholderia gladioli.

Burkholderia↗
PubMed2001

[Establishment of human neuroectodermal tumor cell line (PFSK) with stable expression of xanthine oxidoreductase].

Xanthine Oxidoreductase (XOR) is the key enzyme in purine metabolism and also produces oxygen free radicals. As a continuation of our previous work, in this study, we constructed a retrovirus expression vector (pLNCX2-XOR) containing full length of XOR cDNA. Retrovirus was produced by the virus package cell line PT-67 following the transfection of PT-67 with pLNCX2-XOR and used to infect the human primitive neuroectodermal tumor cell line (PFSK). Infected PFSK cells were selected by G418 to establish cell line with stable expression of XOR. The expression of XOR in the cell line we established was confirmed by RT-PCR, Immunocytochemistry and XOR activity assay.

Genetic Vectors↗
PubMed2001

[Construction of mucosal vaccine derived from HBV surface antigen epitope A and the assay of its immunogenicity].

The fusion gene of HBV(adr) surface antigen epitope and B subunit of Cholera toxin was constructed and expressed successfully in E. coli at high yield. After denaturation-renaturation process, SDS-PAGE analysis showed that most of the renatured product reassociated in a pentameric form which was the same as natural CTB. Western blot analysis indicated that the immunogenicity of HBsAg antigen epitope was conserved. Moreover, ELISA analysis of the sera of orally, intranasally and intraperitoneally immunized mice showed that the circulating IgG antibodies to HBsAg were developed. The results may be helpful for constructing the novel mucosal vaccine with high efficacy.

Animals↗
PubMed2001

[Detection, identification and investigation on small round structured virus in the fecal specimen of diarrhea patients].

The indirect ELISA method with rabbit anti-SRSV superimmune serum on detecting small round structured virus(SRSV) in fecal specimen was established. The result was distinctly different in positive and negative controls, which demonstrated that the ELISA method established in this study was accurate and credible for detecting SRSV. Fecal specimens have been collected from 45 diarrhea patients in Beijing during the autumn and winter in 1998-1999. One specimen showed strong SRSV-positive result and two specimens showed weak SRSV-positive results. Furthermore, SRSV-like virion could be observed in the specimen with strong SRSV-positive result under electronic microscope with phosphate tungsten negative-stain and 60000-fold magnification. But no typical SRSV-like virion could be observed in specimens with weak SRSV-positive results. The rate for SRSV infection in diarrhea patients observed in this study was about 2.2%. The results implicated that SRSV infection was sporadic in Beijing during the autumn and winter seasons in 1998-1999.

Caliciviridae Infections↗
PubMed2001

[Survey on the fumonisins intake and the urinary Sa/So ratio of people suffered from a high incidence of esophageal cancer].

To explore the correlation between fumonisins and human esophageal cancer (HEC), the estimated fumonisin intake and the urinary sphinganine/sphingosine (Sa/So) ratio were investigated in the population with a high HEC incidence in the suburb of Hebi city, Henan province. Fumonisins were detected from 95 percent of corn samples in the endemic area, and the concentration of total fumonisins (fumonisin B1, B2 and B3) was in the range from 7.2 to 726.8 micrograms/kg. The estimated daily intake of fumonisins was in the range from 0 to 4.84 micrograms/(kg.d) in males, while from 0 to 4.04 micrograms/(kg.d) in females. Compared with the population in a low HEC incidence area, Suixian county, Henan province, the urinary Sa/So ratio of males in the endemic area was statistically significant higher, although no difference was observed in females. The results indicated that fumonisin might be one of the risk factors for the occurrence of HEC.

Adult↗
PubMed2001

Effect of 0.2% brimonidine on retinal blood flow.

PURPOSE: To analyze the effect of 0.2% brimonidine eye drops on retinal blood flow of patients with glaucoma. METHODS: Using self-control method and Heidelberg Retina Flowmeter (HRF), we examined the volume, flow and velocity of the superior nasal and temporal, the inferior nasal and temporal artery of retina at baseline and 2 hours after single instillation of 0.2% brimonidine. RESULTS: There were no significant changes in volume, flow and velocity of four vessels before and after the administration of 0.2% brimonidine. CONCLUSIONS: There are no significant ocular haemodynamic benefits associated with Brimonidine therapy to the glaucoma patients.

Adrenergic alpha-Agonists↗
PubMed2001

[The cause and management of acute high intraocular pressure in phacoemulsification].

OBJECTIVE: To investigate the cause and management of acute high intraocular pressure and shallow anterior chamber in phacoemulsification. METHODS: A retrospective study was done on 1,500 eyes performed phacoemulsification. Eleven of 1,500 eyes showed higher intraocular pressure and shallowing of the anterior chamber during phacoemulsification. But phacoemulsification was successfully achieved after giving hyperosmotic agents, increasing infusion pressure and reducing aspiration rate as well as flow rate. RESULTS: Of 11 eyes, 10 eyes were treated by management of non vitrectomy. One of 11 eyes was unresponsive to medical management and require the use of pars plana vitrectomy. Phaco was performed in all patients. In 4 of 11 eyes, visual acuity postoperatively were 0.7 or better. Five of 11 eyes were 0.3 to 0.5. One eye was 0.05 and one was HM/30 cm. CONCLUSION: Aqueous misdirection, retrobulbar hemorrhage and intraoperative suprachoroidal hemorrhage are common causes of acute high intracular pressure in phaco. Most of patients could be performed phaco after medical treatment. If patients failed to improve after medical treatment, par plana vitrectomy is a useful method.

Aged↗