Biomedical subjects

F Zhang

Publications and source records attributed to F Zhang.

At least 145 records · Page 8Linked to original sources

PubMed2001

Thymidine kinase 1 immunoassay: a potential marker for breast cancer.

Previous research indicates that thymidine kinase I (TKI) possesses value as a tool for both prognosis and diagnosis in breast cancer. However, drawbacks to the existing radioassay for thymidine kinase have frustrated its clinical use. To overcome these drawbacks, we developed a monoclonal antibody to TK1. We have assessed this antibody for a linear antibody-antigen response and for reproducibility using ELISA techniques. We also have evaluated this antibody for TKI specificity as determined by Western blot. To test the accuracy of this monoclonal antibody further, we treated human MCF-7 breast cancer cells with tamoxifen and measured decreasing TKI activity and protein levels with the radioassay and with our monoclonal antibody in an ELISA, respectively. We then used the radioassay and our monoclonal antibody to measure TK1 activity and protein levels, respectively, in 218 serum samples of postoperative breast cancer patients and found a correlation between the two assays. Our results demonstrated that the TK1 immunoassay not only had a linear, reproducible, and specific response but accurately measured TK1 levels in both MCF-7 breast cancer cells and serum. Thus, our monoclonal antibody may demonstrate potential for practical use in a clinical setting for the management of breast cancer.

Antibodies, Monoclonal↗

PubMed2001

[Telomere length and DCC gene mRNA expression of human large intestine cancers].

OBJECTIVE: To evaluate the role of telomere and DCC in tumor transformation and progression. METHODS: Telomere length and DCC gene mRNA expression were examined by southern blot hybridization and RT-PCR analysis in 46 adenomas of large intestine, 62 cancers of large intestine and corresponding normal mucosa. RESULTS: Shortening of the telomere was present in the tissues of 41.3% of the adenomas and 53.2% of the cancers, and their average TRF lengths were significantly shorter than those of corresponding normal mucosa(P<0.05, P<0.01), whereas the telomere elongation was only detected in 4.4% and 6.5% of the adenomas and cancers respectively. In addition, the average telomere length in colon carcinomas was also shorter than that in rectal carcinomas. Moreover, the average telomere lengths of the colorectal cancer mucosa became shorter with age. The rates of DCC mRNA expression deletion were 34.8% and 62.9% in the tissues of adenomas and cancers respectively. The DCC mRNA expression deletion occurred more frequently in poorly differentiated and Dukes C, D carcinomas than in well-differentiated and Dukes A, B carcinomas (P<0.05, P<0.01). However, no significant correlation was found between the length of telomere and the deletion of DCC mRNA expression in the cancers of large intestine. CONCLUSION: The telomere shortening and DCC mRNA deletion may represent the biologic behavior of transformation and development of the large intestine cancers.

Adult↗

PubMed2001

Phosphatidylcholine-specific phospholipase C regulates activation of RAW264.7 macrophage-like cells by lipopeptide JBT3002.

Phospholipase activities are thought to be involved in the activation of macrophages by lipopolysaccharide (LPS). Because our previous studies showed that the synthetic lipopeptide JBT3002 might activate macrophages via signaling pathways similar to those used by LPS, we investigated whether phospholipase activities are required for activation of macrophages by JBT3002. Treatment of RAW264.7 murine macrophage-like cells with JBT3002 stimulated expression of both inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-alpha) in a dose-dependent manner. The JBT3002-induced production of nitric oxide and TNF-alpha was significantly inhibited by tricyclodecan-9-yl xanthogenate (D609), a selective inhibitor of phosphatidylcholine (PC)-specific phospholipase C (PC-PLC). JBT3002-induced expression of steady-state mRNA for both iNOS and TNF-alpha was inhibited by D609. Cells treated with JBT3002 had greater production of diacylglycerol (DAG) in 2 min, which lasted for at least 30 min and could be blocked by D609. Activation of RAW264.7 cells was not affected by butanol, a PC-specific phospholipase D inhibitor, and treatment with JBT3002 did not affect phosphatidic acid formation. RAW264.7 cells treated with DAG analogue 1-oleoyl-2-acetyl-sn-glycerol, in the presence of interferon-gamma, produced TNF-alpha. These results suggested that activation of RAW264.7 cells by JBT3002 requires PC-PLC activity.

1-Butanol↗

PubMed2001

[Effects of phenytoin on structural aberration of human sperm chromosomes in vitro].

OBJECTIVE: To detect the mutagenic effects of phenytoin on human sperm chromosomes. METHODS: The mutagenic effects of phenytoin at 10, 20 and 40 microgram/ml were tested by an in vitro testing system of human sperm chromosomes, with leomycin A5 as a positive control and mutagen-free solution as the blank control. RESULTS: The frequencies of sperm with structural chromosomal aberrations and breakages of sperm chromosomes in the groups of 10 microgram/ml, 20 microgram/ml and 40 ug/ml of phenytoin were all higher than those in the blank control, but only in the group of 40 ug/ml, the elevated frequencies were statistically significant (P<0.005, P<0.05). CONCLUSION: Phenytoin has probably mutagenic potential effect on human sperm cells.

Adult↗

PubMed2001

Inducible prostaglandin E synthase is overexpressed in non-small cell lung cancer.

An inducible microsomal form of human prostaglandin E synthase (mPGES) was recently identified. This enzyme converts the cyclooxygenase (COX) product, prostaglandin (PG) H2, to PGE2, a prostanoid that has been implicated in carcinogenesis. Increased amounts of PGE2 are detected in many types of cancer, but the underlying mechanism is not fully understood. Hence, we compared amounts of mPGES in 19 paired samples (tumor and adjacent normal tissue) of non-small cell lung cancer (NSCLC). By immunoblot analysis, mPGES was overexpressed in about 80% of NSCLCs. Immunohistochemistry localized the expression of mPGES to neoplastic epithelial cells. COX-2 was also commonly up-regulated in these tumors; marked differences in the extent of up-regulation of mPGES and COX-2 were observed in individual tumors. Cell culture was used to define the underlying mechanism(s) that accounts for up-regulation of mPGES in NSCLC. As reported previously for COX-2, levels of mPGES mRNA and protein were increased in NSCLC cell lines containing mutant Ras as compared with a nontumorigenic bronchial epithelial cell line. Nuclear run-offs revealed increased rates of mPGES transcription in the transformed cell lines. Overexpression of Ras caused a severalfold increase in mPGES promoter activity in nontransformed cells. Tumor necrosis factor-alpha induced mPGES and COX-2 in NSCLC cell lines but had no effect on the expression of either enzyme in a nontumorigenic bronchial epithelial cell line. Consistent with prior observations for COX-2, these data suggest that both cellular transformation and cytokines contribute to the up-regulation of mPGES in NSCLC.

Carcinoma, Non-Small-Cell Lung↗

PubMed2001

[An evaluation on corrosion resistance of magnetic retainers].

OBJECTIVE: The present study was to explore the corrosion resistance of three kinds of magnetic retainers which named neodymium-iron-boron magnet and encapsulated in stainless steel. METHODS: Three kinds of magnetic retainers were exposed for 6 months to artificial saliva thermostated at 36.5 degrees C. This study included a electrochemical test as polarization curves and a chemical test as immersion test. RESULTS: In the electrochemical test, current density of the national keeper was 7.015 microA/cm2 and magnet was 0.119 microA/cm2. In the chemical test, corrosion rate of national keeper was 3.67 x 10(-5) mg/cm2.h and magnet was 1.77 x 10(-5) mg/cm2.h. The corrosion resistance of the national magnetic retainer had little difference with the imported ones. CONCLUSION: Transient exposure of stainless steel to artificial saliva environment is likely to significantly increase elemental release. It would affect the useful life span of magnets.

Corrosion↗

PubMed2001

Inhibition of nicardipine on amygdala kindling in rats.

AIM: To investigate the effects and mechanism of nicardipine, a calcium channel blocker, on amygdala kindling in rats. METHODS: Constant current stimulations were delivered to the right amygdala of the rats once a day. The effects of nicardipine on the development and seizure of amygdala kindling were observed and the content of amino acid neurotransmitters in the brain of kindled rats was determined. RESULTS: Nicardipine (2 mg . kg-1, ip) significantly retarded the development of amygdala kindling (P < 0.01); 2 - 20 mg . kg-1 of nicardipine inhibited amygdala kindled seizure dose-dependently, elevated the afterdischarge threshold, and reduced the Racine's stage; 20 mg . kg-1 of nicardipine significantly increased the content of GABA, a kind of inhibitory amino acid neurotransmitter, in the brain of amygdala kindled rats (P < 0.05). CONCLUSION: Nicardipine inhibits amygdala kindling in rats, and the inhibition mechanism may be related to the blockage of the voltage-operated calcium channels and the enhancement of GABAergic system action in the brain.

Amygdala↗

PubMed2001

[The implications of the biological indices examination of bone marrow cells in myelodysplastic syndromes].

OBJECTIVE: To explore the biological characteristics of the hematopoietic cells in myelodysplastic syndromes(MDS) and the relationship between the biological indices and the disease progressing. METHODS: R banding technique for karyotype analysis, in vitro semi-solid culture for CFU-GM growth patterns, flow cytometry after monoclonal antibody labeling for proliferation cell nuclear antigen (PCNA) expression, flow cytometry after in vitro bromodeoxyuridine (BrdU) incorporation for cell cycle kinetics analysis, and X-linked HUMARA gene polymorphism assay for hematopoiesis clonality analysis were carried out in 37 MDS patients. RESULTS: 1. Cytogenetic abnormalities were detected in 31% of the MDS patients and AML transformation occurred in 2 of 9 with normal and 3 of 5 with abnormal chromosomal karyotypes. 2. The mean CFU-GM colony yield was decreased and cluster yield increased in the MDS patients. Disease progression in 6 of 9 with more CFU-GM cluster yields, while only 1 of 9 with either normal or no CFU-GM yields transformed into AML. 3. Percentages of PCNA-positive BMMNCs were significantly higher in MDS patients than in normal control (44.22% vs 26.82%, P < 0.01). RAEB/RAEB-t subtypes had significantly higher PCNA-positive cells (P < 0.01). 4. The mean BrdU labeling index of MDS marrow cells was lower (5.07%), the mean DNA synthesis time (Ts) and potential doubling time(Tpot) of MDS patients were longer than that of normal control (p < 0.01), and the increased Ts and T pot were related to the disease progression. 5. Monoclonal pattern of BMMNCs was detected in 5 of 7 heterozygous female RA patients and the other 2 were polyclonal hematopoiesis. All 3 RAEB and 1 MDS/AML were monoclonal hematopoiesis. CONCLUSION: With disease progressing and bone marrow blasts increasing, the biological nature of the hamatopoetic cells in MDS exhibited a tendency to transformation as follows: hematopoiesis converting into clonal, in vitro CFU-GM growth pattern approaching leukemic, PCNA expression increasing, and cell cycle prolonging.

Adolescent↗

PubMed2001

Intrathecal injection with methotrexate plus dexamethasone in the treatment of central nervous system involvement in systemic lupus erythematosus.

OBJECTIVE: To investigate the effect of intrathecal injection (i.t.) with methotrexate (MTX) plus dexamethasone (DXM) in treating central nervous system involvement in systemic lupus erythematosus (CNS lupus). METHODS: Twenty-four CNS lupus patients that were refractory to conventional steroid therapy were selected for i.t. with MTX 10-20 mg plus DXM 10-20 mg. The effects and side effects of i.t. were closely observed. RESULTS: The symptoms and signs of 22/24 (91.7%) CNS lupus patients receiving i.t. improved considerably. Cerebrospinal fluid pressure, protein and WBC levels declined from 201.5 +/- 155.4 mm H2O, 145.2 +/- 87.6 mg/dl and 25.1 +/- 14.3/mm3 to 128.7 +/- 108.1 mm H2O, 60.8 +/- 38.3 mg/dl and 6.8 +/- 2.1/mm3 respectively. Transient side effects were observed in 4 patients: 1 with itching sensation of lower limbs, 2 with headache and 1 with incontinence. CONCLUSION: I.t. with MTX plus DXM is a promising method for treating CNS lupus and deserves further investigation.

Adolescent↗

PubMed2001

Apolipoprotein E polymorphism in the early onset of coronary heart disease.

OBJECTIVE: To assess the relationship between apolipoprotein E (apoE) polymorphism and the early onset of coronary heart disease (CHD) and the effect of apoE on lipids and lipoproteins in healthy Chinese subjects. METHODS: Sixty-eight patients with CHD younger than 55 years (CHD1), 136 patients with CHD older than 65 years (CHD2), and 136 healthy subjects were enrolled, and their plasma levels of triglyceride (TG), total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C) were determined. The apoE genotypes were identified by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: apoE 3/4 genotype and E4 allele frequency in the CHD1 group were higher than those in the CHD2 group and healthy subjects, while no differences were found between CHD2 and healthy subjects. Meanwhile, the plasma levels of TC and low density lipoprotein cholesterol (LDL-C) were higher in the CHD2 group than in both CHD1 group and healthy subjects. Each apoE isoprotein has variable TC and LDL-C levels that is E2 (E2/2 + E2/3) < E3(E3/3) < E4(E4/4 + E3/4). CONCLUSION: apoE is one of the genetic factors that affect TC and LDL-C levels, and apoE 4 has a very close relation to CHD, suggesting that apoE 4 is an independent genetic factor of the early onset of CHD.

Adult↗

PubMed2001

[Value of P-glycoprotein and glutathione S-transferase-pi as chemo-resistant indicators in ovarian cancers].

OBJECTIVE: This study was conducted to assess the predictive value of P-glycoprotein (P-gp) and glutathione S-transferase-pi(GST-pi) as indicators of resistance to chemotherapy in ovarian cancers. METHODS: Expressions of P-gp and GST-pi were immunohistochemically studied in paraffin sections from 30 normal ovaries and 74 resected specimens of primary epithelial ovarian cancer from patients who had not received any chemotherapy before surgery. RESULTS: There were no detectable P-gp or GST-pi expression in the 30 patients with normal ovaries. In 74 cases of ovarian cancer tissue, P-gp was positive in 14 (18.9%) and GST-pi positive in 55 (74.3%) showing a highly significant correlation (P < 0.01). However, expression of P-gp and GST-pi was not associated with any of the clinicopathological parameters, such as clinical stage, histologic or tumor grade (P > 0.05). The evaluation of chemotherapy for postoperative residual ovarian cancer patients showed that all the six lesions showing P-gp positive were drug-resistant whereas only nine of the twenty-one tumors showing negative results were drug-resistant. Of 27 clinically measurable resected lesions, this difference in the response rates of the two groups was significant (P < 0.05). The predictive value of positive P-gp stain for drug resistance was 100% (6/6), and that of negative stain for objective responders was 57.1%(12/21). The response rate to chemotherapy of the GST-pi positive group (13.3%-2/15) was significantly lower than that of the SGT-pi negative group (83.3%-10/12, P < 0.01). The predictive value of positive GST-pi stain for drug resistance was 86.7%(13/15) and that of negative stain for objective responders was 83.3%(10/12). The survival rates of P-gp negative and GST-pi negative tumor patients were significantly higher than those of P-gp positive and GST-pi positive tumor patients (P < 0.01, P < 0.05, respectively). CONCLUSION: These data suggest that P-gp and GST-pi expression in tumor cells are related to drug resistance in epithelial ovarian cancer. They are useful indicators of resistance to chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

[A study on relationship between blood lead level in children and fetal umbilical cord].

OBJECTIVE: To study the relationship between blood lead level in children and fetus. METHODS: Blood specimens were collected from the fingers of children aged one to five years and from umbilical cord when the babies were born, to determine their lead level with atomic absorption spectrophotometry. RESULTS: The average blood lead level was (0.42 +/- 0.15) micromol/L in 1 122 children. Blood lead level in 27.54% of the children was above >/= 0.483 micromol/L. The average umbilical blood lead level was (0.16 +/- 0.12) micromol/L in 127 neonates. Blood lead level in 0.79% of the new-born babies were greater than >/= 0.483 micromol/L. CONCLUSION: Higher blood lead level in children was mainly caused by environmental pollution and unhealthy life behaviors. Background blood lead in fetuses has already reached a higher level, so prevention from lead poisoning in children should begin during pregnancy.

Child, Preschool↗

PubMed2001

[The study of low dose radiation inducing hormesis effect on hematopoietic system].

OBJECTIVE: To study the hormesis effect on hematopoietic system induced by low dose radiation. METHOD: CFU-GM and BFU-E were cultured in methylcellulose semi-solid culture system, levels of GM-CSF and IL-3 were assayed by ELISA and mRNA levels of GM-CSF, G-CSF, IL-3 by in situ hybridization, narrow line hybridization and Northern blot. RESULTS: (1) The in vitro yields of CFU-GM and BFU-E from radiated mice was higher than that from the control. (2) The serum protein level of GM-CSF increased obviously than that of controls; (3) mRNA levels of GM-CSF and G-CSF were also increased. CONCLUSION: There is hormesis effect on hematopoietic system induced by low dose radiation, which may be related to the increasing of cytokines.

Animals↗

PubMed2001

[Anti-virus effect of combination of attenuated measles virus with 3TC on duck hepatitis B model].

OBJECTIVE: To evaluate the anti-virus effect of combination of attenuated measles virus with 3TC on duck hepatitis B model. METHODS: Guanzhou brown spot ducklings infected with DHBV were divided into three groups. Drug treatments including measles vaccine, 3TC and both measles vaccine and 3TC were given in the 13th day after the infection, respectively. Serum samples were obtained from all ducklings before, during and after treatment at different times and stored at -70 degrees C. DHBV DNA was detected by Dot-blot hybridization. RESULTS: Compared with the levels of DHBV DNA before and after treatment, no statistic difference was found in group of 3TC alone. The levels of DHBV DNA were not changed in group of measles vaccine alone in early stage, but decrease of DHBV DNA occurred after stopping treatment (comparison of the levels T13 with before treatment and T13 of positive group, P < 0.01 and P < 0.05, respectively). DHBV DNA level in group of measles vaccine combined with 3TC was obviously lower at 5th day after the treatment than in both measles vaccine and 3TC alone groups at the same time(P < 0.05 and P < 0.01, respectively), and it remained low when the treatment was discontinued. CONCLUSION: Attenuated measles virus combined with 3TC may have early and long-lasting inhibiting effect on the replication of DHBV.

Animals↗

PubMed2001

[Study of the reconstruction methods after vertical partial laryngectomy for glottic carcinoma of the larynx].

OBJECTIVE: To study the reconstruction methods after vertical partial laryngectomy for glottic carcinoma of the larynx. METHOD: 58 cases with glottic carcinoma of the larynx were treated with vertical partial laryngectomy or extended vertical partial laryngectomy. The clinical materials of these cases were retrospectively studied. RESULT: The total decannulation rate was 93.1% and the 3- and 5-year survival rates were 87.2% and 80.5% respectively. The voice was socially acceptable in 93.1%(54/58) of the patients. Aspiration was only 3. All resumed mouth-food-taking. CONCLUSION: The reconstruction methods after vertical partial laryngectomy were mainly decided by the extent of the laryngeal defect. If the laryngeal defect of the framework was small, the pedicle muscular flap was the best reconstruction method in comparison with other reconstruction methods. If the laryngeal defect of the framework was too big, allograft nasal septal cartilage or epiglottic laryngoplasty should be performed.

Aged↗

PubMed2001

[Role of epithelial cell proliferation and apoptosis in human middle ear cholesteatoma].

OBJECTIVE: To determine the role of middle ear epithelial cell proliferation and apoptosis in the pathogenesis of human cholesteatoma. METHOD: 33 cholesteatoma, 25 auditory meatal skin of cholesteatoma and 10 normal human auditory meatal skin were detected by using immunohistochemistry analysis for cell proliferation with Ki 67, PCNA and PCNA antibody and TUNTEL methods for cell apoptosis. RESULT: PCNA expression and apoptosis cells exists different quantity in cholesteatoma, auditory metal skin of cholesteatoma and normal human auditory meatal skin and distributes in various cell layer. There were positive correlation between p53 and PCNA as well as negative correlation between p53 and apoptosis. CONCLUSION: The dyregulation of proliferation and apoptosis in keratinocyte is important in pathogenesis of cholesteatoma.

Adolescent↗

PubMed2001

[Studies on transference of hydrogenase genes of Rhizobium arachis].

The hydrogen-uptake genes were transferred into wild Rhizobium arachis Ra strains (Hup-, Nif+, Apr) by triparental mating using pRK2013 as help plasmid. A transconjugant R. arachis Rz34-2(Hup+, Nif+, Apr, Tcr) which expressed high activities of hydrogenase and nitrogenase under free-living and symbiotic state was screened. Peanut inoculation test with recipient R. arachis Ra34, transcojugant Rz34-2 and control strain R. arachis L8-3 (Hup+, Nif+) was carried out respectively. The results showed that, compare to treatment without inoculation, inoculation with R. arachis Ra34 and R. arachis L8-3, the dry weight of leaf inoculated with transconjuant Rz34-2 increased 6.2%, 7.6% and 6.3% respectively; the N-content of seed increased 8.8%, 10.0% and 6.0%; the output increased 18.8%, 10.5% and 10.7%. This suggested that legume plants inoculated with Rhizobium strains (Hup+) were more efficient to accumulate N and to increase its output.

Arachis↗

PubMed2001

[Noninvasive measurement of gastric emptying rates and gastric motility].

A non-invasive measuring system is developed for the assessment of gastric evacuation and motility by means of epigastric impedance measurement. FIR digital filters realized on personal computer were used for signal filtering and cancellation of respiratory interference. Electrodes of concentric type placed anterior and posterior were proved to be more effective for epigastric impedance measurement.

Electric Impedance↗