Biomedical subjects

G Lu

Publications and source records attributed to G Lu.

At least 55 records · Page 3Linked to original sources

PubMed2001

Apoptosis inducing effects of arsenic trioxide on human bladder cancer cell line BIU-87.

OBJECTIVE: To explore the apoptosis inducing effects of arsenic trioxide (As2O3) on human bladder cancer cells and elucidate possible mechanisms. METHODS: After treatment with As2O3, the growth inhibition rates of human bladder cancer cell line BIU-87 were studied by MTT and cell counts methods. DNA synthesis rates were detected by 3H-TdR assay. The morphological changes of cancer cells were observed by light and electronic microscopy and cell apoptosis rates were detected by TdT-mediated dUTP nick end labeling (TUNEL). bcl-2 gene expression of BIU-87 cells was observed by strept avidin-biotin complex (SABC) immunohistochemical method. RESULTS: As2O3 could effectively inhibit the growth of BIU-87 (P < 0.05), which were time and concentration dependent. The inhibition rate of 4.0 mumol/L As2O3 for DNA synthesis of cancer cells was 55.64% (P < 0.01). Partial cancer cells presented the characteristic morphological changes of apoptosis which depended on the time of exposure to drug (P < 0.05). bcl-2 expression of BIU-87 cells was decreased significantly (P < 0.05). CONCLUSION: As2O3 can significantly induce apoptosis in bladder cancer cells by down-regulating the expression of the bcl-2 gene and inhibiting DNA synthesis. This provides a potentially effective method for prevention and cure of human bladder cancer.

Antineoplastic Agents↗

PubMed2001

[A clinical report on hydrophilic acrylic foldable lens implantation].

OBJECTIVE: To investigate the therapeutic effects of hydrophilic acrylic foldable lens implantation. METHODS: This prospective randomized placebo-controlled study comprised 214 eyes of 190 patients after phacoemulsification. The hydrophilic acrylic foldable lens was implanted in group 1 (114 eyes), and the PMMA intraocular lens (IOL) implanted in the control group 2 (100 eyes). Within the 3-6 month follow-up period, the changes of visual acuity, corneal astigmatism and endothelial cells, the location of IOL and the degree of posterior capsular opaqueness postoperatively between the two groups were compared. RESULTS: The visual acuity of group 1 was significantly better than that of group 2 within 3 days postoperatively (P < 0.05), but there was no statistically significant difference after 3 months. The surgically induced astigmatism, incidents of posterior capsular opaqueness and subluxation of IOL of group 1 were significantly lower than that of group 2 after 3 months postoperatively (P < 0.05). The comparison of the endothelial cell loss ratio between the two groups was not significantly different (P > 0.05). CONCLUSION: The hydrophilic acrylic foldable IOL is easy to handle during implantation, highly biocompatible in the eyes, with less postoperative inflammatory reactions and shorter recovery period, and may provide satisfactory therapeutic effects.

Acrylic Resins↗

PubMed2001

[An experimental study on the effects of NGF on the wound healing of deep partial thickness burn in pigs].

OBJECTIVE: To investigate the effects of nerve growth factor (NGF) on wound healing of deep partial thickness burn in pigs. METHODS: Six pigs of about 20 kg each were employed as the model. Twenty -- four deep partial thickness burn wounds (2.5 cm in diameter per wound) were made on the back of each pig by temperature and pressure controller. Six wounds were set to be one group. The wounds were randomly divided into 4 groups, i.e. control group (applied with normal saline, C), three treatment groups with NGF topically applied in doses of 1, 2.5 and 5 microgram/ml, respectively. Histological examination, determination of hydroxyproline, analysis of cellular DNA cycle and wound healing time in every groups were carried out on 3, 5 and 9 postburn days (PBD). RESULTS: The proliferation rate of epithelia was much more active in treatment groups than in control group. Epithelization of the wound in treatment groups was earlier than of that in control group. The hydroxyproline content in treatment groups exhibited an increment after a prior decrement, especially on 5 PBD when the content was much lower in the treatment groups. The analysis of cellular DNA cycle indicated that cell number of S phase in treatment groups was obviously more than that in the control group. Furthermore, the wound healing time in treatment groups was much shorter than that in control group. CONCLUSION: Local application of NGF might promote the wound healing of deep partial thickness burn.

Animals↗

PubMed2001

[Studies on the methods of mating test for Cryptococcus neoformans].

Six media (MA:Mating agar, HA:Hay agar, HCA:Hay cube agar, RSA:Rice shell agar, IHA:additional nutrition in HA and SDA:Sabouraudia dextrose agar) were compared for their efficiencies of the mating test for Cryptococcus neoformans. The positive rates in 2-week-cultivation were 95% (HCA and RSA), 86% (HA), 38% (MA and SDA) and 24% (IHA). The streaking inoculation was equally replaced by the dot inoculation for the mating tests. However, the dot method saves much more materials, and is suitable for testing in large number of isolates. Additionally, the precultivation of the tester and tested isolates in broth medium (YMPDB) could enhance the positive mating rates.

Agar↗

PubMed2000

Preliminary study of the in vitro growth inhibition of human bladder cancer cell line BIU-87 by arsenic trioxide.

To study the effects of arsenic trioxide (As2O3) on the in vitro growth of human bladder cancer cells and the mechanisms. The growth inhibition rates of human bladder cancer cell line BIU-87 by various concentrations of As2O3 were detected by using MTT method. Cell apoptosis was detected by in situ terminally labeled transferase technique and bcl-2 gene expression of BIU-87 cells was observed by SABC immunohistochemical method. The results showed that As2O3 could inhibit the growth of BIU-87 effectively in a dose-dependent manner. After drug's action, the apoptotic bladder cancer cells were obviously increased, which depended on the prolongation of the action time and Bcl-2 expression of BIU-87 cells was decreased significantly. It was suggested that As2O3 could significantly inhibit the growth of bladder human cancer cells. Inducing cell apoptosis by down-regulating the expression of bcl-2 gene might be one of its action mechanisms.

Antineoplastic Agents↗

PubMed2000

The structural basis of substrate activation in yeast pyruvate decarboxylase. A crystallographic and kinetic study.

The crystal structure of the complex of the thiamine diphosphate dependent tetrameric enzyme pyruvate decarboxylase (PDC) from brewer's yeast strain with the activator pyruvamide has been determined to 2.4 A resolution. The asymmetric unit of the crystal contains two subunits, and the tetrameric molecule is generated by crystallographic symmetry. Structure analysis revealed conformational nonequivalence of the active sites. One of the two active sites in the asymmetric unit was found in an open conformation, with two active site loop regions (residues 104-113 and 290-304) disordered. In the other subunit, these loop regions are well-ordered and shield the active site from the bulk solution. In the closed enzyme subunit, one molecule of pyruvamide is bound in the active site channel, and is located in the vicinity of the thiazolium ring of the cofactor. A second pyruvamide binding site was found at the interface between the Pyr and the R domains of the subunit in the closed conformation, about 10 A away from residue C221. This second pyruvamide molecule might function in stabilizing the unique orientation of the R domain in this subunit which in turn is important for dimer-dimer interactions in the activated tetramer. No difference electron density in the close vicinity of the side chain of residue C221 was found, indicating that this residue does not form a covalent adduct with an activator molecule. Kinetic experiments showed that substrate activation was not affected by oxidation of cysteine residues and therefore does not seem to be dependent on intact thiol groups in the enzyme. The results suggest that a disorder-order transition of two active-site loop regions is a key event in the activation process triggered by the activator pyruvamide and that covalent modification of C221 is not required for this transition to occur. Based on these findings, a possible mechanism for the activation of PDC by its substrate, pyruvate, is proposed.

Catalytic Domain↗

PubMed2000

Cloning and functional analysis of cDNAs with open reading frames for 300 previously undefined genes expressed in CD34+ hematopoietic stem/progenitor cells.

Three hundred cDNAs containing putatively entire open reading frames (ORFs) for previously undefined genes were obtained from CD34+ hematopoietic stem/progenitor cells (HSPCs), based on EST cataloging, clone sequencing, in silico cloning, and rapid amplification of cDNA ends (RACE). The cDNA sizes ranged from 360 to 3496 bp and their ORFs coded for peptides of 58-752 amino acids. Public database search indicated that 225 cDNAs exhibited sequence similarities to genes identified across a variety of species. Homology analysis led to the recognition of 50 basic structural motifs/domains among these cDNAs. Genomic exon-intron organization could be established in 243 genes by integration of cDNA data with genome sequence information. Interestingly, a new gene named as HSPC070 on 3p was found to share a sequence of 105bp in 3' UTR with RAF gene in reversed transcription orientation. Chromosomal localizations were obtained using electronic mapping for 192 genes and with radiation hybrid (RH) for 38 genes. Macroarray technique was applied to screen the gene expression patterns in five hematopoietic cell lines (NB4, HL60, U937, K562, and Jurkat) and a number of genes with differential expression were found. The resource work has provided a wide range of information useful not only for expression genomics and annotation of genomic DNA sequence, but also for further research on the function of genes involved in hematopoietic development and differentiation.

Alternative Splicing↗

PubMed2000

[Detection of Prader-Willi syndrome by methylation-specific PCR].

OBJECTIVE: Using a faster and more efficient method to diagnose Prader-Willi syndrome(PWS). METHODS: Differential DNA methylation at several sites in the PWS critical region where the maternal homologue is unmethylated and transcriptionally active. Methylation-specific PCR(MSPCR) is based on sodium bisulfite treatment of DNA, which converts unmethylated but not methylated cytosine residues to uracil, and PCR primers specific for the maternal and the paternal allele. Methylation analysis by Southern blot is made to validate the MSPCR result. RESULTS: Bisulfite-modified DNA from PWS patients amplified only with methylated allele-specific primer pair showed only maternal 174bp PCR product. MSPCR and PW71B methylation studies showed an abnormal pattern consistent with the clinical diagnosis of PWS. Untreated DNA does not produce a PCR product. CONCLUSION: MSPCR can be used to detect all presently testable causes of PWS (deletion, uniparental disomy, and imprinting mutation) in an efficient first step for stepwise diagnostic testing, compared with either Southern blot analysis which is more timeconsuming, or fluorescence in situ hybridization(FISH) which can not detect uniparental disomy or imprinting mutation.

Adolescent↗

PubMed2000

[Analyzing study of complications of tissue expansion related to the injectable system].

OBJECTIVE: To analyze the complications of tissue expansion related to its injectable system. METHODS: One hundred and ninety six patients were followed up and analyzed for the complications of the tissue expansion concerned to its injectable system. The management of these complications was also reviewed. RESULTS: There were five kinds of the complications(with the occurrence of 32%) related to the injectable system in this group patients. The highest frequency of the complications occurred in the implantation stage. Further management was also documented well. CONCLUSION: The complications of tissue expansion related to the injectable system occurred commonly and should be paid more attention on them.

Adolescent↗

PubMed2000

Soluble cell adhesion molecules in patients with acute coronary syndrome.

OBJECTIVE: To observe the changes in serum soluble intercellular adhesion molecule type-1 (ICAM-1), vascular cell adhesion molecule type-1 (VCAM-1), E-selectin and von Willebrand factor (vWf) in patients with acute coronary syndrome. METHODS: Serial venous blood samples were taken from 21 patients with acute myocardial infarction (AMI) before and 4, 8, 12, 24, 48 and 72 h after thrombolytic treatment or direct PTCA. One blood sample was drawn from 16 patients with unstable angina and 16 control subjects. Serum concentrations of ICAM-1, VCAM-1, E-selectin and vWf were determined using a double antibody sandwich enzyme-linked immunosorbent assay. RESULTS: Serum levels of ICAM-1, VCAM-1, E-selectin and vWf were higher in patients with acute coronary syndrome than in controls. Patients with AMI and successful reperfusion therapy had a significant reduction in the serum concentration of ICAM-1 and E-selectin at 24 and 48 h, VCAM-1 at 24 and 72 h and vWf at 12, 24, 48 and 72 h, but had peak in serum levels of ICAM-1 and E-selectin at 4 h. The number of diseased coronary arteries was not related to the levels of ICAM-1, VCAM-1 and E-selecin. CONCLUSION: The serum concentration of soluble cell adhesion molecules was elevated significantly in patients with acute coronary syndrome. Successful reperfusion therapy was associated with a reduction in the serum concentrations of soluble cell adhesion molecules in patients with AMI.

Aged↗

PubMed2000

[Establishment of MRP-overexpression subline of bladder carcinoma and its MDR phenotype].

OBJECTIVE: To investigate MRP expression and multidrug resistance(MDR) phenotype of a bladder carcinoma subline transfected with the full length MRP cDNA. METHODS: After transfection, a stable MRP-overexpressed subline named EJ/MRP was established. Gene expression of MRP and mdr1 were detected by using RT-PCR and immunohistochemistry methods. Drug sensitivity testing of the EJ/MRP cells to 11 kinds of anti-cancer agents was examined. RESULTS: Compared with EJ/Vect which was mock transfected, MRP mRNA level of EJ/MRP increased 14.3 fold and MRP expression was mainly located in cytosol and plasma membrane. The relative resistance (RR) to VP-16, vincristine increased more than 10 fold, and that to doxorubicin, hydroxycamptothecin, thiotepa, mitomycin and cyclophosphamide increased 3 to 10 fold. CONCLUSION: Bladder carcinoma with stably over-expressed MRP presents typical MDR phenotype but without mdr1/P-gp expression. It provides a good model and positive control for the study of MRP-mediated MDR.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2000

[Study on the hepatitis virus infection among medical professionals].

OBJECTIVE: In order to find out the present situation of hepatitis virus infection among medical professionals. METHODS: 140 medical professionals were studied on their serum HBsAg, anti - HBs, anti - HCV using EIA, and HEV - IgG, HGV - IgG with ELISA. RESULTS: The infection rates of HBsAg, HCV, HEV and HGV of medical professionals were 7.8%, 1.4%, 7.1% and 7.1% respectively with an overall infection rate of 23.5%. The infection rates for the clinical group and the non - clinical group were 33.3% and 12.3% respectively [with significant differences (P < 0.01)]. The infection rates of HEV and HGV for the clinical group were 8.0% and 12.0% respectively. It was found no superimposing infection in non - clinical group but was in clinical group. CONCLUSION: The result suggested that the infection rate of hepatitis virus in the medical professionals in the clinical group was higher than in the non - clinical group.

Adult↗

PubMed2000

[A study on incidence of injury and its socio-economic loss in children and young adults].

OBJECTIVES: To study the current status of incidence of injury among children and young adults and the causes of common injuries, and to estimate its socio-economic loss and extent of harmfulness. METHODS: Pupils in 19 primary and middle schools aged 7 to 18 years, totaling 14,533, were recruited with stratified cluster sampling during 1998 to 1999 in Guangzhou, Maoming, Jiangmen and Shantou. Judgement for injury was based on the following criteria: (1) diagnosed and treated in hospitals or school clinics, (2) a half-day off or more due to injury, and (3) emergency management by pupils' parents or teachers. RESULTS: There were 6 941 pupils suffered from varied injures during the year, with an incidence rate of 47.76% (50.08% for boys and 45.02% for girls). Incidence rate of injury was higher in the middle school pupils (13 - 18 years old, 58.49%) than that in the primary school pupils (7 - 12 years old, 40.08%). The incidence increased significantly with age, with a peak at ages of 13 - 15. Major causes of injuries resulted from falls, injury by sharp articles, collision, traffic injuries and burn/scalds, etc, which usually occurred due to carelessness in sports, playing, walking, bike-riding and working. Frequency of multiple injuries related to the educational level of parents and depended on whether or not an only-child in family. There were 2,173 injured pupils (accounting for 31.3% of the total) visited clinics or emergency department in hospitals and 627 (9.0%) hospitalized for treatment. Twenty-eight percent of the injured pupils were absent from school, with an average absenteeism of 5.6 days. There were 154 injured pupils with transient disability and 53 with permanent disability, with a disability rate of 410.47 per 100,000. Cost for their medical care averaged 81.5 yuan RMB per injured pupil. CONCLUSIONS: Injury was a common and frequently-happened incident among children and young adults and could seriously affect their health, development and growth, studying and their future of children and young adults. Health education, safety-promotion and removing hidden danger for injury are the major measures to prevent from injury, and the government and the whole society should pay great attention to injury issues in children and young adults.

Accidents↗

PubMed2000

[A comprehensive evaluation on intervention measures for injuries in primary and middle school students].

OBJECTIVE: To explore the intervention measures for prevention and control of injuries and evaluation for their effectiveness in students of middle and primary schools. METHODS: Effectiveness of intervention was evaluated by comparison of incidence of injury before and after intervention in 3,896 students of nine middle and primary schools and comparison with a non-intervention group in 651 students of four primary schools in Jiangmen City, Guangdong Province during January to December, 1999. RESULTS: Incidence of injury dropped to 11.78% after intervention from 50.55% before intervention in the intervention group, with 76.70% of reduction. Proportion of severe injury dropped to 0.65% after intervention from 7.84% before intervention. Incidence of multiple injuries dropped to 3.15% from 19.16%, with 83.56% of reduction. But, in the control group, incidence of injury dropped to 49.00% from 52.67%, with 6.97% of reduction only, with a ratio of reduction of intervention to control of 11.02% and a ratio of cost to benefit of 1:13.9. CONCLUSION: Intervention measures focusing on health promotion can prevent and control the occurrence of injury in students of middle and primary schools cost-effectively.

Accident Prevention↗

PubMed2000

[Comparative study of three common G6PD gene mutations in Yao and Han People in Guangxi].

OBJECTIVE: To study G6PD gene mutation diversity in Yao and Han people in Guangxi and compare the genotypic frequencies. METHODS: The three common G6PD gene mutations in Chinese were investigated in 34 G6PD deficient individuals from Yao and 37 from Han people by using an amplification refractory mutation system (ARMS). RESULTS: Among 34 cases of G6PD deficiency of Yao people, the genotypic frequencies of G1376T, G1388A and A95G were 41.2%, 26.5% and 14.7%, respectively. A case of C1311T was detected. As compared with that in Han people, the respective frequencies were 16.2%, 40.6% and 5.4%. CONCLUSION: The main G6PD mutations in Yao people were the same with Han people in Guangxi, but G1376T mutation was higher than that in Han people. The C1311T mutation in Yao people in Guangxi was reported for the first time.

Adolescent↗

PubMed2000

[Chaos in electroencephalogram].

The history and current situation of EEG study were reviewed in the paper, with an emphasis on the application and the latest developments of chaos in EEG analysis. The problems in present study and the proposals for future investigations were finally discussed.

Algorithms↗

PubMed1999

Comparison of the peroxidase reaction kinetics of prostaglandin H synthase-1 and -2.

Prostaglandin H synthase isoforms 1 and 2 (PGHS-1 and -2) each have a peroxidase activity and also a cyclooxygenase activity that requires initiation by hydroperoxide. The hydroperoxide initiator requirement for PGHS-2 cyclooxygenase is about 10-fold lower than for PGHS-1 cyclooxygenase, and this difference may contribute to the distinct control of cellular prostanoid synthesis by the two isoforms. We compared the kinetics of the initial peroxidase steps in PGHS-1 and -2 to quantify mechanistic differences between the isoforms that might contribute to the difference in cyclooxygenase initiation efficiency. The kinetics of formation of Intermediate I (an Fe(IV) species with a porphyrin free radical) and Intermediate II (an Fe(IV) species with a tyrosyl free radical, thought to be the crucial oxidant in cyclooxygenase catalysis) were monitored at 4 degrees c by stopped flow spectrophotometry with several hydroperoxides as substrate. With 15-hydroperoxyeicosatetraenoic acid, the rate constant for Intermediate I formation (k1) was 2.3 x 10(7) M-1 s-1 for PGHS-1 and 2.5 x 10(7) M-1 s-1 for PGHS-2, indicating that the isoforms have similar initial reactivity with this lipid hydroperoxide. For PGHS-1, the rate of conversion of Intermediate I to Intermediate II (k2) became the limiting factor when the hydroperoxide level was increased, indicating a rate constant of 10(2)-10(3) s-1 for the generation of the active cyclooxygenase species. For PGHS-2, however, the transition between Intermediates I and II was not rate-limiting even at the highest hydroperoxide concentrations tested, indicating that the k2 value for PGHS-2 was much greater than that for PGHS-1. Computer modelling predicted that faster formation of the active cyclooxygenase species (Intermediate II) or increased stability of the active species increases the resistance of the cyclooxygenase to inhibition by the intracellular hydroperoxide scavenger, glutathione peroxidase. Kinetic differences between the PGHS isoforms in forming or stabilizing the active cyclooxygenase species can thus contribute to the difference in the regulation of their cellular activities.

Animals↗

PubMed1999

Expressions of recombinant venom allergen, antigen 5 of yellowjacket (Vespula vulgaris) and paper wasp (Polistes annularis), in bacteria or yeast.

Antigen 5 is a major allergen of vespid venom. It has partial sequence identity with proteins from diverse sources. The biologic function of Ag 5 and its related proteins is not known. We are interested in the expression of Ag 5 with the native conformation of the natural protein since its B cell epitopes are mainly of the discontinuous type. When expressed in bacteria, recombinant Ag 5 formed an insoluble intracellular product, and it did not translocate from cytoplasm to periplasm by the addition of a pelB leader sequence to the cloned protein. When expressed in yeast Pichia pastoris, Ag 5 was secreted because the cloned protein contained a yeast alpha signal leader sequence. Recombinant Ag 5 from yeast was shown to have the native structure of the natural protein and the recombinant Ag 5 from bacteria did not. This was shown by comparison of their solubility, electrophoretic behavior, disulfide bond content, CD spectrum, and binding of IgE antibodies from allergic patients and IgG antibodies from mice immunized with natural Ag 5 or recombinant Ag 5s from yeast or bacteria. These studies were made with Ag 5s from yellowjacket (Vespula vulgaris) and paper wasp (Polistes annularis).

Amino Acid Sequence↗