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Biomedical subjects

Y Lü

Publications and source records attributed to Y Lü.

At least 19 recordsLinked to original sources
PubMed2001

[Analysis of the methylation in CpG island by denaturing high-performance liquid chromatography].

OBJECTIVE: To establish a new approach for analyzing methylation circumventing the limitations of the existing methods. METHODS: A region containing CpG sites in mismatch repair gene hMLH1 promoter was amplified by strand-specific polymerase chain reaction (PCR) after sodium bisulfite treatment. The retention time of the PCR product at partially denaturing temperature was determined by denaturing high-performance liquid chromatography (DHPLC). The methylation status obtained by DHPLC was proved by comparing it with that from sodium bisulfite-restriction enzyme digestion. RESULTS: Methylation of hMLH1 promoter from a colorectal cancer cell line RKO and a gastric cancer cell line PACM82 was analyzed by DHPLC. The retention time of the PCR product from RKO was obviously longer than that from PACM82 (6.7 min vs. 6.2 min). Thus, it was concluded that the hMLH1 promoter from RKO was methylated, while that from PACM82 was not, since the longer retaining time of RKO was due to the higher C/G content after sodium bisulfite treatment. The results from DHPLC were consistent with those from sodium bisulfite-restriction enzyme digestion. CONCLUSION: DHPLC method is a rapid and reliable approach for analyzing methylation in CpG island of the sequence of interest.

Adaptor Proteins, Signal Transducing↗
PubMed2001

[Current evolution of plasma sprayed hydroxyapatite coating].

The present attempt is to briefly review the processing and properties of plasma sprayed hydroxyapatite coatings in terms of characteristics of hydroxyapatite ceramics, plasma spraying technology, titanium-ceramic interfacial cracking and component designing of hydroxyapatite coating based composite. The coating is a weak part in implant system. The main purpose of research on plasma spraying technology and component designing is to improve coating integrality and coating-matrix adhesion strength. Functionally gradient materials can provide a new route to solve the above two problems.

Biomechanical Phenomena↗
PubMed2001

[An analysis for causes of skeletal relapse after correction of mandibular prognathism by BSSRO].

OBJECTIVE: To investigate the factors responsible for the skeletal relapse after correction of mandibular prognathism by BSSRO. METHODS: The skeletal and dental changes before and after the surgery were analysed by cephalometrics, The factors that might be responsible for the skeletal relapse were evaluated using multiple linear and partial correlation analysis. RESULTS: The changes of NP-FH angle at follow up had a significant correlation with MP-FHT4-3 angle, the duration of presurgical orthodontics and the observation period after surgery(r = -0.568, -0.406, -0.400, P < 0.01-0.05). CONCLUSION: The skeletal relapse following BSSRO was limited. The stability was related to the period of presurgical orthodontics and the mandibular rotation after the surgery.

Female↗
PubMed2001

[Anti-tumor effect of E1B55kDa-deleted adenovirus on human hepatocellular carcinoma cell lines].

OBJECTIVE: To investigate the in vitro and in vivo anti-tumoral effect of E1B55kDa-deleted adenovirus (dl1520) on human hepatocellular carcinoma (HCC) cell lines. METHODS: Human HCC cell lines with different p53 genotypes were infected with dl1520. Four days after infection, the percentage of survival cells was determined by colorimetric assay. RT-polymerase chain reaction (PCR) was used to examine alterations of p53 and p21Waf-1 expression. Adenovirus hexon gene expression was applied to prove the presence of adenovirus infections. Effects on vivo anti-tumor dl1520 were examined with intra-tumor injection of dl1520 in the SCID mice. RESULTS: After the infection, the p53-null HCC cell line, Hep3B was most vulnerable to dl1520 induced cytotoxic effect with a cell death rate of more than 60%. Whereas, less than 20% PLC/PRF/5 (p53-mutant) and HepG2 (p53-wild type) HCC cell lines were killed. The expression of p53 and p21Waf-1 was considerably enhanced after the dl1520 infection in HepG2. The intra-tumor injection of dl1520 significantly reduced the tumor growth in Hep3B xenografts. In contrast, no obvious tumor repression was observed in HepG2 and PLC/PRF/5 xenografts. CONCLUSION: dl1520 selectively kills the p53-null hepatocellular carcinoma, showing potential application for cancer treatment.

Adenovirus E1B Proteins↗
PubMed2000

[Isolation of genes associated with renoprotective effects of astragalus and angelica by silver staining mRNA differential display].

OBJECTIVE: To isolate genes associated with chronic progression of renal diseases and renoprotective effects of Astragalus and Angelica(A & A). METHODS: Chronic puromycin nephropathy, which is characterized by massive proteinuria and progressive glomerular sclerosis and tubulointerstitial fibrosis, was induced in SD rats by repeated peritoneal injections of puromycin. Rats were randomly divided into three groups: (1) normal control (n = 7), (2) puromycin nephropathy without A&A treatment (n = 7), (3) puromycin nephropathy A & A treatment (3 ml/d, n = 7). After 12 weeks, serum, urine and renal tissue were collected for study. The technique of silver staining mRNA differential display (DD) was used to investigate the changes of gene expression in kidneys of normal and nephropathy with and without A&A treatment rats. Genes expressing differently during the progression of renal diseases were isolated and the progression could be normalized by A&A. RESULTS: Twenty-six candidate cDNA fragments were isolated with DD. Northern blot analysis of eight randomly chosen candidate cDNA fragments demonstrated one exhibiting reduced mRNA expression in the fibrogenic process but upregulated by A&A treatment. Besides kidney, the gene was also expressed in lung, heart, liver and spleen. Whether it takes part in fibrogenic processes of these organs needs further study. Homology analysis through BLAST revealed that this gene was a novel one. CONCLUSION: Silver staining mRNA differential display is a simple and quick technique for isolating differently expressed genes. The downregulated expression of the isolated new gene may contribute significantly to the fibrogenic process and be associated with A&A's protective effects.

Angelica sinensis↗
PubMed2000

[Analysis of facial profile preferences among the Chinese population].

OBJECTIVE: To determine the preferences of Chinese population for facial profile esthetics. METHODS: 400 panelists were randomly selected from Chinese cultural and educational backgrounds. Subjects were asked to rank the five distinct facial profiles of yellow race in descending order of attractiveness. RESULTS: The ranking was as follows: B, A, E, D, C. The differences in rank scores among all the profile types were statistically significant (P < 0.05). CONCLUSIONS: 1. Given a choice between an orthognathic or a more retrusive profile, Chinese public tended to prefer the latter; 2. The preferences for facial profile esthetics were not influenced by sex, age and educational level.

Adult↗
PubMed2000

[Treatment of Class II division 1 malocclusions with single maxillary extraction orthodontics].

OBJECTIVE: To investigate the effects, indications and clinical significance of single maxillary extraction orthodontics used for class II division 1 malocclusions. METHODS: 14 class II division 1 patients were treated by single maxillary extraction orthodontics, the cephalometric data before and after treatment were analysed by statistical methods. RESULTS: After treatment, 1. the angle 1-FH had decreased by 11.03 degrees and the angle 1-MP had increased by 3.07 degrees; 2. The mandibular length had increased by 3.30 mm; 3. the upper and lower lip were retruded by 2.65 mm and 1.64 mm respectively. Statistical significance (P < 0.001-0.05) was found between the means before and after treatment. CONCLUSIONS: Single maxillary extraction orthodontics is suitable for class II division 1 patients with less labial tipping of lower incisors and less lip protrusion.

Adolescent↗
PubMed1999

The distribution of substance P receptor (NK1)-like immunoreactive neurons in the newborn and adult human spinal cord.

Substance P receptor (i.e. NK1)-like immunoreactive (SPR-LI) neurons were observed in the newborn and adult human spinal cord. Substance P receptor-like immunoreactive neuronal cell bodies were seen most frequently in lamina I, and were scattered throughout the remaining laminae of the dorsal horn and the area around the central canal. Some neurons in the intermediolateral nucleus also showed weak immunoreactivity. The pattern of distribution of SPR-LI neurons in the adult spinal cord was essentially the same as that in the newborn spinal cord. However, SPR-LI neurons cell bodies were seen much more frequently in the newborn than in the adult dorsal horn, especially in lamina II.

Adult↗
PubMed1999

Effects of acupuncture on the pituitary-thyroid axis in rabbits with fracture.

PURPOSE: To observe the effects of acupuncture on the pituitary-thyroid axis in rabbits with fracture. METHOD: 36 male rabbits with a 3-mm width experimental defect in the middle segment of the left radius were randomly divided into the treatment group and control group, and the changes in serum T3, T4 and TSH contents in different weeks were investigated. RESULTS: Serum T3, T4 and TSH contents in the treatment group all were higher than those in the control group, with statistically significant differences in the contents of T4 and TSH in the second week and T3 content in the fourth week (P < 0.01 or P < 0.05). CONCLUSION: The action of promoting union of fracture is possibly related with the pituitary-thyroid axis.

Animals↗
PubMed1999

[A surveillance study on penicillin-resistant Streptococcus pneumoniae in China].

OBJECTIVES: To find out if there are penicillin-resistant Streptococcus pneumoniae and the resistance rate in China. METHODS: 989 pediatric patients with respiratory tract infections aged from 6 months to 3 years from two pediatric units were enrolled. Perthroat swabs were immediately streaked onto blood agar plates and incubated overnight. Pneumococci were identified and isolated. Antibiotic susceptibility was assessed by the disk diffusion method and MIC determination according to Protocol and NCCLS. RESULTS: Of the 51 Streptococcus pneumoniae isolates, 5 strains had zones > or = 20 mm. Two of the 5 strains had penicillin MICs > or = 0.1 mg/L (2 and 4 mg/L) and considered to be fully resistant to penicillin(4%). The resistance rate to ceftriaxone and cefotaxime was 0 and 4% respectively. For the other 10 antimicrobial agents, the resistance rates were as follows: ampicillin 12%, piperacillin 26%, furbenicillin 14%, cefuroxime 6%, erythromycin 54%, clarithromycin 52%, meleumycin 64%, roxithromycin 52%, chloramphenicol 32%, and tetracycline 100%. CONCLUSIONS: The study suggested that penicillin resistant Streptococcus Pneumoniae strains also exist, and the cross-resistance is a significant phenomenon in China.

Ampicillin Resistance↗
PubMed1999

[Relationships between mandibular canine calcification stages and skeletal maturity].

OBJECTIVE: To study the relationship between mandibular canine calcification and skeletal maturity. METHODS: Hand wrist and mandibular canine radiographs of 106 boys and 152 girls in Beijing area were assessed. RESULTS: Mandibular canine calcification coincides with the initiation of puberty in male (93.8%) and with the deceleration of puberty in female(89.7%). However the coincidence with the indicators of other pubertal stages was less than 50%. CONCLUSION: Mandibular canine calcification just can give an initial assessment for estimating the timing of puberty.

Adolescent↗
PubMed1999

[A study of interferon alpha-2b as an accessory drug after glaucoma filtration surgery].

OBJECTIVE: To elucidate the inhibitory action of interferon alpha-2b (IFN alpha-2b) on the cicatrization under conjunctiva and the best way to use it after glaucoma filtration surgery. METHODS: Immunohistochemical PAP method and image biological system 2000 (IBAS 2000) were utilized to quantitatively analyze the inhibitory effect of IFN alpha-2b on the expression of epidermal growth factor receptor (EGFR) of cultured calf fibroblasts; the effects of IFN alpha-2b on collagen contents in suture-caused cicatrization under conjunctiva and changes of aqueous humor protein after trabeculectomy performed on rabbits have also been observed. RESULTS: IFN alpha-2b reduced the expression of EGFR of cultured bovine fibroblasts at a dose-dependent manner. The relationship between the EGFR and the dosage of IFN alpha-2b is Y = 2953.8 - 554.5 lgx (r = -0.98, P < 0.01). With 4.67 x 10(-5) micromol/L IFN alpha-2b not only reduced about 50% of the collagen in suture-caused cicatrization, but also significantly decreased the protein concentration of aqueous humour 3 and 72 hours after trabeculectomy. CONCLUSION: It is promising that IFN alpha-2b can be used after glaucoma filtration surgery to reduce excessive cicatrization with many advantages compared with antimetabolites.

Animals↗
PubMed1998

Study on delay two-phase multiple organ dysfunction syndrome.

OBJECTIVE: To study the injury factors, pathogenic process and clinical features of delay two-phase multiple organ dysfunction syndrome (MODS) in severe burned patients and to replicate a standardized animal model that would accurately imitate the clinical features of MODS. METHODS: Forty-five human patients with burn size larger than 30% total body surface area (TBSA) were analyzed. All of them underwent severe burn shock in early stage and sepsis in late stage. Thirty-two goats were randomly divided into three groups: 1) hemorrhagic shock (group H, n = 6); 2) endotoxemia (group E, n = 6); and 3) hemorrhagic shock plus endotoxemia (group M, n = 20). Hemorrhagic shock was produced according to the method of Wigger (6.7 kPa for an hour, 1 kPa = 7.5 mmHg). Endotoxin (E. coli O111 B4) was given via the portal vein 24 hours after the resuscitation of hemorrhagic shock, in a dose of 30 ng/kg/min for 5 consecutive days. During the observation period of 10 days, all animals were hemodynamically monitored, given standard metabolic support and due cardiac and pulmonary support according to human intensive care. RESULTS: All the patients showed burn shock at 1-3 days and hyperdynamic circulation, hypermetabolism and systemic inflammatory responses over two weeks post-injury. Thirteen cases were found to develop MODS according to the prevailing diagnostic criteria, and 10 of them died with a mortality of 77%. Eighteen animals died in group M with a mortality of 90%, 12 of the 18 developed MODS, with overall incidence of 60%. Most animals in group M showed changes similar to that observed in human cases. The experimentation proved that in the pathogenic process of MODS, there was a two-hit phenomenon in the dvelopment of the syndrome. To prevent the development of MODS, it therefore was imperative to blunt the first hit or the second hit, so that an excessive inflammatory response was alleviated. This postulation has been verified in the treatment of extensive burns. Two patients with burn extent reaching 100% TBSA survived with only mild acute respiratory distress syndrome (ARDS) and renal dysfunction after comprehensive treatment of burn shock, including adequate fluid resuscitation, drugs to remove oxygen free radicals, rapid restoration of pHi, and early extensive excision of burn eschars. CONCLUSION: Both in human patients or animal experimentation, the typical delay two-phase MODS is shown to be produced by two successive insults in the forms of hypovolemic shock and sepsis. This postulation is helpful in formulating the prevention and treatment modality of MODS.

Adult↗
PubMed1998

[Expression of p53 and ras p21 gene products in malignant transformed V79 cell induced by various organic components of DEPs].

The effect of various fractions of diesel exhausted particles on the expression of mutant p53 antigen product and ras oncogene p21 product was examined by immunohistochemical method in malignant transformed V79 cell. The result showed that all fractions of diesel exhausted particles (DEPs) could significantly increase the expression of p53 products (P < 0.01). It demonstrated that the organic fractions of DEPs could induce the mutation of p53 suppressor gene in malignant transformed cells. But the expression levels of ras oncogene p21 product were not changed under the same experimental conditions (P > 0.05).

Animals↗
PubMed1998

[High frequency mutation of p53 gene in human gastric cancer and precancerous lesions].

OBJECTIVE: To determine the frequency and type of p53 gene mutation with the progression of human gastric carcinogenesis. METHODS: Single strand conformation polymorphism (SSCP) and DNA sequencing were performed on 56 biopsied tissues, including gastric cancer (n = 23), dysplasia (Dys, n = 16) and intestinal metaplasia (IM, n = 17). RESULTS: p53 gene mutation was detected in 60.1% of cancer, 31.3% of Dys and 11.8% of IM. Mutations covered exon 5-8 without hot spot. GC-->AT transitions (30.4%) and GC-->TA transversions (26.1%) were the major patterns of p53 mutation. Missense (73.9%) and frame shift mutations covered 86.9% of all mutations. CONCLUSION: In the process of human gastric carcinogenesis, multiple factors are involved in p53 gene mutations. The mutation rate increases with the progression of malignant changes in the gastric mucosa. Missense and frame shift mutations are possibly the major cause of p53 inactivation.

Adenocarcinoma↗
PubMed1998

[The influence of pressure on human lamina cribrosa cell and its collagen synthesis].

OBJECTIVE: To study the influence of pressure on human lamina cribrosa cell (HLC) and its synthesis of collagen. METHOD: HLCs were cultured in vitro and submitted to elevated hydrostatic pressure, their changes in morphology were observed by light and electron microscopy and their synthesis of collagen was measured with fluorescence spectrophotometer. RESULTS: Under a hydrostatic pressure of 6.67 kPa (1 kPa = 7.5 mmHg), the flat and polygonal HLCs became elongated. Vacuoles appeared in the cytoplasm and increased as the pressure persisted. The mitochondria were swollen, some of them turned into vacuoles, and myelin figures were found in the cytoplasm. When exposed to elevated pressure for 3 days, the amounts of synthesized collagen type I, III, IV were 43.95 +/- 6.37, 61.35 +/- 10.35 and 82.90 +/- 11.36 arbitrary unit (AU) by fluorometry respectively, and compared to controls, they were statistically significantly (P < 0.05) increased; after 5 days of pressure exposure, the amounts were 33.50 +/- 6.94, 40.85 +/- 12.30 and 80.45 +/- 14.65 AU, e.g., still increased. CONCLUSION: It is indicated that under pressure, HLCs undergo obvious morphological changes and increase their synthesis of collagen types I, III and IV.

Collagen↗
PubMed1998

[A preliminary observation on vitrectomy combined with autologous platelet concentrate for the treatment of idiopathic macular holes].

OBJECTIVE: To investigate the efficacy of vitrectomy combined with autologous platelet concentrate for the treatment of idiopathic macular holes. METHODS: Fifteen eyes of 14 patients with idiopathic macular hole were treated. The follow-up period ranged from 3 to 16 months. Postoperatively, visual acuity, macular threshold, Amsler grid, fluorescein angiography (FA) and complications were evaluated. RESULTS: Of the fifteen eyes, the closure of the holes was achieved in 13 eyes (86.7%), visual acuity improved for two lines or more in 12 eyes (80.0%). The postoperative visual acuities in patients with abnormal Amsler grid were improved. No significant differences were found in the macular threshold (P = 0.34). Postoperative FA showed that the blocked fluorescence at the site of the macular hole which was surrounded by a hyperfluorescence ring (window defect) in three eyes. The intraoperative complication was primarily the retinal hole, and the postoperative complication was chiefly the aggravation of cataract. CONCLUSIONS: These results indicate that vitrectomy combined with autologous platelet concentrate can seal the macular hole well and improve the visual acuity in most patients. A large multicenter randomized prospective study and a longer period of follow-up are needed to verify these results.

Blood Transfusion, Autologous↗