Search PubMed⌕ Search

Biomedical subjects

Y Tang

Publications and source records attributed to Y Tang.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Progress in studies on the mechanism of substance addiction in central nervous system].

The mechanism of substance addiction in the central nervous system is the key point to solve the problem of drug addiction in clinical prophylaxis and treatment, but it has been obscure so far. Previous researches in this field suggested that the higher brain function of the learning and memory might be pivotal in understanding the mechanism of substance addiction. It is the intent of this review to integrate and analyze the substance addiction and the learning and memory in an attempt to shed light on the strategies to conduct further studies in this field.

Central Nervous System↗
PubMed2001

[Combined gene therapy for murine liver cancer with interleukin-18 and cytosine deaminase genes].

OBJECTIVE: To investigate the synergistic antitumor effects of murine IL-18 and CD/5FC gene therapy on mice bearing liver cancer. METHODS: A retrovirus vector pGCEN/IL-18 containing murine interleukin-18 gene was constructed. The retrovirus carrying IL-18 gene was used to infect murine liver cancer cell MM45T.Li, and proved to secret biological active IL-18. In mice bearing liver cancer, (60)Co-irradiated MM45T.Li/IL-18 vaccine was inoculated subcutaneously once a week for two weeks, and/or AdCD was injected intratumorally with 5FC injected i.p. for 8 days. RESULTS: Thirty days from the treatment, the tumor volume of control group was 1580 approximately 1625 mm(3), MM45T.Li/IL-18 vaccine group was 366 +/- 159 mm(3), AdCD/5FC group was 438 +/- 65 mm(3), and combined IL-18 and AdCD/ 5FC therapy group was 15 +/- 7 mm(3) (P<0.05). The tumor volume in single gene therapy group reduced to the smallest after three-week treatment, but grew large again, while the tumor volume in combined therapy group still remained small. The median survival time in control group was 50.0 approximately 51.5 days, MM45T.Li/IL-18 group was 65 days, AdCD/5FC group was 57 days versus 75 days for combined gene therapy group (P<0.05), and with more abundant infiltration of CD4+ and CD8+ lymphocytes around the tumor in combined gene therapy group. CONCLUSIONS: Combined gene therapy with IL-18 and CD/5FC can reduce the tumor volume and elicit the antitumor immunity of the host, which is superior to the single gene therapy for murine liver cancer.

Animals↗
PubMed2001

Relationship between c-fos gene expression and delayed neuronal death in rat neonatal hippocampus following hypoxic-ischemic insult.

OBJECTIVE: To explore the mechanism of perinatal hypoxia-ischemia encephalopathy, we studied the expression of the c-fos gene and its relationship with delayed neuronal death in a rat model. METHODS: Cerebral hypoxia-ischemia was produced in 7-day-old SD rats using the Rice model. Reverse transcription PCR (RT-PCR), immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) were used to detect the expression of c-fos gene and cell apoptosis in the hippocampus. RESULTS: The selective expression of c-fos and delayed cell apoptosis were observed in the hypoxia-ischemia hippocampus. Expression of the c-fos gene was seen in the CA4 and cingulate sulcus neurons, and apoptosis was observed in the CA1 neurons. CONCLUSION: Transient expression of the c-fos gene may induce cerebral cell apoptosis, and may have complex relations with delayed cell death.

Animals↗
PubMed2001

[Hypermethylation of the calcitonin gene as molecular genetic marker in detecting minimal residual disease of leukemia].

OBJECTIVE: To explore whether detecting minimal residual disease (MRD) of leukemia with hypermethylation of the calcitonin gene as molecular genetic marker of leukemic clone may predict the prognosis. METHODS: Polymerase chain reaction (PCR) in combination with digestion of DNA with HpaII was used to examine the methylation patterns of the calcitonin gene in 29 cases with acute leukemia and 8 cases with transformation of chronic myeloid leukemia. By using PCR, MRD was longitudinally detected in patients who were positive for hypermethylation of the calcitonin gene as molecular genetic marker. RESULTS: Twenty patients with acute leukemia and transformation of chronic myeloid leukemia had MRD after complete remission. Bone marrow relapse occurred soon when MRD persisted or reappeared. It may predict bone marrow relapse two to eleven months earlier. The patients who were negative for MRD early and remained persistently negative may acquire prolonged survival. CONCLUSION: MRD of leukemia may be monitored by using PCR with hypermethylation of the calcitonin gene as molecular genetic marker for leukemic clone. It may prove useful in predicting the prognosis of leukemia.

Adult↗
PubMed2001

[Study on mutations of beta chain of high-affinity IgE receptor gene in people of Han nationality of southern China].

OBJECTIVE: To detect mutations of beta chain of high-affinity IgE receptor (Fc epsilon RI-beta) gene and analyze the association between its mutation and asthma in people of Han nationality of southern China. METHODS: Amplification refractory mutation system-polymerase chain reaction technique was used to determine 3 mutations (I181L, V183L and E237G) at Fc epsilon RI-beta gene in 60 unrelated patients with asthma and 65 healthy controls from people of Han nationality of southern China. RESULTS: (1) The mutation V183L was not detected in patient and control groups. (2) The only one heterozygous for I181/L181 was found in patient group, and no homozygous for L181/L181. (3) The frequency of Glu237/Gly237 genotype is 18.3% in patient group, and 6.2% in control group. The frequency of Gly237 gene is 9.2% in patient group, and 3.1% in control group. (4) There was a significant difference in the frequencies of Glu237/Gly237 genotype and Gly237 gene. CONCLUSION: These results suggest that E237G mutation of Fc epsilon RI-beta gene presents in people of Han nationality of southern China, and is correlated with asthma. There are the lack or very low frequencies of V183L and I181L mutations in people of Han nationality of southern China.

Adolescent↗
PubMed2001

[Evaluation of saliva ferning test in diagnosis of Sjögren's syndrome].

OBJECTIVE: To evaluate saliva ferning test in (SFT) diagnosis of xerostomia in patients with Sjögren's syndrome (SS). METHODS: Dried samples of freshly produced saliva from 78 patients diagnosed as SS according to european community criteria and 80 healthy controls were examined by light microscopy. The crystallization was classified into 4 types according to the ferning phenomenon: uniformity, branching, spreading and integrity (type I normal and type II, III, IV abnormal). Then, the 78 patients underwent labial salivary gland biopsy. According to Tarpley's classification of labial gland biopsy, > or = 2+ was considered positive. RESULTS: (a) The sensitivity and specificity of SFT were 89.74% (70/78) and 83.75% (67/80) respectively. (b) Abnormal SFT was observed in 70/78 (89.74%) of SS and in 13/80 (16.25%) of normal controls. The differences of SFT in SS patients versus normal controls were significant (P < 0.01). (c) The sensitivity of SFT and labial gland biopsy had no significant differences (P > 0.05) as diagnostic tests in SS. CONCLUSIONS: SFT was valuable as a diagnostic test in patients suspective of SS.

Adolescent↗
PubMed2001

[Effects of vitamin A and iron supplementation on the improvement of iron status and immunological function in preschool children].

OBJECTIVE: In order to understand the changes in immunological function in rural preschool children with lower levels of vitamin A and iron, and the effect of vitamin A and iron supplementation on the improvement of iron status and immunological function. METHODS: Serum vitamin A concentration and hemoglobin (Hb), serum iron (SI), transferrin saturation (TS), serum ferritin (SF) were determined in 270 rural preschool children aged 3-7 years in Beijing, and the subjects were divided into four groups based on their determinations: control, lower serum vitamin A, lower iron, and both lower iron and serum vitamin A. Forty subjects were selected from each group, and serum IgA, IgG, IgM and interleukin-2 (IL-2) were determined for them. Forty-one subjects who had lower iron and lower serum vitamin A (< 1.12 mumol/L) were divided into two groups: one of them supplemented with 30 mg iron element (ferrous sulfate 0.15 g) once a day for 8 weeks, and the other group supplemented with iron and 12,500 IU vitamin A twice a week for 8 weeks. After supplementation of vitamin A and iron, their serum vitamin A, hematological iron index and serum immunological index were determined again for the two groups. RESULTS: Serum IgM were (1,260 +/- 310) mg/L in both lower iron and serum vitamin A groups, significantly higher than that in normal group (1,070 +/- 170) mg/L (P < 0.05). But there were no significant differences in serum levels of IgG, IgA and IL-2. After supplementation of iron and vitamin A, their serum TS increased to (26.5 +/- 8.6)%, significantly higher than that before supplementation and that supplemented with iron only (22.3 +/- 3.8)%. And, their serum IL-2 were (278.9 +/- 117.7) ng/L after supplementation, significantly higher than that before supplementation (161.6 +/- 90.3) ng/L and that in those supplemented with iron only (189.5 +/- 89.3) ng/L. There was no significant difference in other biochemical indices of iron and immunological indices. CONCLUSIONS: Supplementation with vitamin A and iron was helpful to improve body iron nutritional status and immunological function obviously in preschool children with iron-deficiency and sub-clinical deficiency of vitamin A.

Child↗
PubMed2001

[Detection and partial nucleotide sequence analysis of hepatitis G virus in sera of patients with hepatitis in Guangzhou].

OBJECTIVE: To investigate hepatitis G virus (HGV) infection in hepatitis patients and the gene type of HGV in Guangzhou. METHODS: Reverse transcriptase-nested polymerase chain reaction(RT-nested PCR) method using primers locating in noncoding region of HGV genome was used for detecting HGV RNA in sera of hepatitis patients and the amplified products were directly sequenced. RESULTS: 25 cases were HGV RNA positive in 251 sera of acute and chronic hepatitis(9.96%), of which 4 cases were positive in 56 sera with hepatitis non A-E(7.14%), 8 cases were positive in 77 sera with hepatitis B (10.39%), 13 cases were positive in 118 sera with hepatitis C(11.17%). The identity of nucleotide sequence was 98.0% between 2 Guangzhou HGV isolates, both were 91.1% with American isolate, 81.7% and 84.2% respectively between 2 Guangzhou isolates and African isolate. CONCLUSION: HGV infection exists in hepatitis patients, 2 Guangzhou HGV isolates may belong to the same gene type and both of them have a high homology with American HGV isolate.

Base Sequence↗
PubMed2001

[Audiological findings of the aging across the urban and rural of Suzhou].

OBJECTIVE: To determine the epidemiological characteristics of old people's hearing. METHOD: Questionnaires, physical examination, audiometry and bio-chemical tests were performed on the elders above 60 years old in part of the urban and rural area of Suzhou with random sample survey. RESULT: A total of 1,040 individuals was investigated, among which 505 were from urban, and 535 were from rural. 33 of 505 senior citizen (6.53%) were nososacusis, 282 (55.84%) were presbycusis and 21 (4.16%) were noise-induced deafness; In the rural area, 35 of 535 (6.54%) were nososacusis, 232 (43.36%) were presbycusis, and 4 (0.75%) were noise deafness. There was significant difference of the incidence of presbycusis between urban and rural. The audiometric thresholds chart manifested that the threshold elevated with age increasing especially in high-frequency. CONCLUSION: The etiology of hearing loss of elders was mainly due to presbycusis. The higher incidence of psychotic disorder in urban probably caused a correspondingly higher incidence of presbycusis. So the prevention and cure of some age-induced diseased (e.g. hypertension, arteriosclerosis and diabetes) may be helpful to release and improve presbycusis.

Aged↗
PubMed2001

[LC/MS research on the isomers of special melanoma antigen-encoding gene-2 epitope peptide induced by solvent].

To study the influence of different solvent systems on the isomers of melanoma antigen-encoding gene-2(MAGE-2) epitope peptide synthesized by Marrifield's solid synthesis method, MAGE-2(171-179) epitope peptides were pre-treated using ethanol and methanol systems respectively, and then analysed by RP-HPLC/MS, with dimethyl-sulphoxide (DMSO) as control solvent. Results demonstrated that 100% ethanol and 100% methanol solvents could induce the production of isomers of MAGE-2, while 100% DMSO, 50% ethanol and 50% methanol could not. These isomeric peptides could be reversed greatly if treated with trifluoroacetic acid (TFA). The results also showed that the analysis would be distorted and the yield of peptides would decrease dramatically if the peptides were pre-treated with high concentrations of ethanol and methanol before RP-HPLC analysis and preparation. Thus it is suggested that it might be better to decrease the concentration of organic phase in the solvent system for the resolvable hydrophobic peptides, acidified ethanol and methanol might also be better for the highly hydrophobic peptides, and DMSO would be a good solvent for hydrophobic peptides analysis provided that it would not influence the resolving power of chromatography.

Antigens, Neoplasm↗
PubMed2001

[Extraction of DNA from environmental samples and construction of mixed genomic DNA libraries].

A method has been developed for extracting and purifying genomic DNA from environmental samples. In this method, an environmental sample is treated first by grinding and freezing/thawing and subsequently by SDS/proteinase K-based DNA extraction. The yields of purified DNA from three samples used in this study ranged from 2 to 16 micrograms per gram of dry sample. Mixed genomic DNA libraries for two of the environmental samples were constructed by inserting restriction fragments (3-8 kb) of the purified DNAs into plasmid pUC18 and transforming E. coli DH5 alpha with the resultant plasmids. Approximately 10(3) to 10(4) insert-containing clones were obtained from 1 g of each sample. Clone libraries were analyzed by DNA sequencing and gene annotation. Among 20 randomly-selected clones, 14 contained an insert whose sequence had not been reported while the rest had an insert of either E. coli or vector origin. A search of sequence databases using the end sequences of each of the foreign inserts showed that each sequence was part of a gene encoding, in most cases, a predictable function. Our results are of significance to the collection, investigation and exploitation of the genes of uncultured microorganisms.

Amino Acid Sequence↗
PubMed2001

[Purification and properties of chitinase from Enterobacter aerogenes].

A bacterium producing chitinase was isolated from the dead body of Gymephorap ruoergensis. A chitinase was isolated from the culture of E. aerogenes and purified by means of ammonium sulfate precipitation, DEAE-cellulose column chromatography, and Sephadex G-100 column gel filtration. The purified chitinase showed homogeneity on the native polyacrylamide gel electrophoresis. Its molecular weight was estimated to be about 42.5 kD by SDS-PAGE. The optimum pH and temperature for hydrolysis of chitin were 6.0 and 55 degrees C respectively. Michaelis constant was 2.88 mg/mL. Different metal ions showed different effects on the chitinase activity, The chitinase activity was enhanced by Zn2+, Ba2+, Ca2+, Mn2+ and was strongly inhibited by Hg2+, Co2+, Mg2+.

Animals↗
PubMed2001

[Homologous recombination in Streptomyces lincolnensis B48].

To study frequency and mechanism of homologous recombination in Streptomyces, an E. coli plasmid which cannot replicate in Streptomyces was transformed into Streptomyces lincolnensis B48. After homologous recombination between delta lincomycin biosynthetic genes inactivated by thiostrepton resistant gene (tsr) carried on pYYE04al and homologous sequences on the chromosome, S. lincolnensis YY1 and S. lincolnensis, YY2 were obtained on SMA with low thiostrepton concentration. Hybridization of chromosomal DNA samples of S. lincolnensis YY1, S. lincolnensis YY2, standard S. lincolnensis and S. lincolnensis YYc digested with SmaI with the probe of tsr gene gave signal corresponding to a fragment of 1.5 kb in the former two; Nevertheless, hybridization of chromosomal DNA digested with Hind III and Sma I using the probe of delta lacZ' gene resulted in positive fragment of 4.4 kb only in S. lincolnensis YY2. Southern hybridizations indicate that S. lincolnensis YY1 is the result of homologous exchange while S. lincolnensis YY2 comes from bomologous recombination. To prove the existence of E. coli replicon and ampicillin resistant gene on the chromosome of S. lincolnensis YY2, its DNA digested with SphI was ligated and then transformed into E. coli JM83 competent cell. Two transformants named pSLE1 grew on the plate containing ampicillin. It's confirmed that pSLE1 is a part of pYYE04a1 from its digestion with different enzymes.

Chromosomes, Bacterial↗
PubMed2001

[Effects of quanjia yangshen capsule on rate of polychromatic erythrocytic micronucleus formation and peripheral blood picture in mice treated by cyclophosphamide].

OBJECTIVE: To observe the effect of Quanjia Yangshen capsule (QJYS) on cyclophosphamide (Cy) induced teratogenesis and bone marrow in mice and to explore the mechanism of its clinical therapeutic effect. METHODS: Mice were separately administered with QJYS solely, Cy solely and QJYS + Cy and the effect on polychromatic erythrocytic (PE) micronucleus formation rate in the bone marrow of mice, and peripheral blood picture were observed and compared with the control group. RESULTS: High dosage of QJYS has no apparent effect on PE micronucleus formation rate and peripheral blood picture in the normal mice; Cy can obviously raise PE micronucleus formation rate (P < 0.01), and lowered WBC, RBC and Hb obviously (P < 0.01) in mice. After taking QJYS, the Cy induced micronucleus formation rate increasing and blood picture parameters lowering were controlled. The improvement in the high and middle dose QJYS group was significantly higher in comparing to that in the sole Cy group (P < 0.01); while the low dose QJYS group in comparing with Cy group also showed significant improvement (P < 0.01), except Hb value. CONCLUSION: QJYS could significantly antagonize teratogenic effect and inhibition to bone marrow of Cy, i.e., play an antagonistic role against the toxic and side-effects of Cy.

Animals↗
PubMed2001

[Study on hypermethylation of the calcitonin gene in malignant hematological disorders].

OBJECTIVE: To investigate the clinical significance of hypermethylation of the calcitonin (CT) gene in malignant hematological disorders (MHD). METHODS: Polymerase chain reaction (PCR) in combination with digestion of DNA with Hpa II was used to examine the methylation patterns of the CT gene in 73 patients with MHD, 6 healthy people and 24 patients with nonmalignant hematological disorders (NON-MHD). RESULTS: Hypermethylation of the CT gene occurred in 12 of 14 (85.7%) patients with acute lymphoblastic leukemia (ALL), 9 of 15 (60%) acute nonlymphocytic leukemia (ANLL), 8 of 10 (80%) chronic myelogenous leukemia (CML), 5 of 15 (33.3%) malignant lymphoma (ML), 2 of 5 patients with myelodysplastic syndrome (MDS), 1 of 2 malignant histiocytosis (MH), 1 of 3 chronic lymphocytic leukemia (CLL) and 1 of 9 multiple myeloma (MM). However, it did not occur in normal controls and NON-MHD. CONCLUSION: Hypermethylation of CT gene may serve as an important molecular maker for tumorous cell clone and may be useful in diagnosing MHD, monitoring minimal residual disease and predicting prognosis.

Calcitonin↗
PubMed2001

Endogenous expression and HLA stabilization assay of Plasmodium falciparum CTL epitope minigene in human HLA-A2. 1 and HLA-B51 cells.

OBJECTIVE: To evaluate the Plasmodium falciparum CTL epitope vaccines in HLA class I allele specific human cell lines that have high frequency among Chinese population. METHODS: Synthesized oligonucleotides encoding for P. f. CTL epitope genes, constructed eukaryotic expression plasmids, transfected the minigenes into HLA class I allele specific human cell lines and identified endogenous expressing of the minigenes by RT-PCR and HLA stabilization assay. RESULTS: Two mini-genes encoding Plasmodium falciparum CTL epitopes were designed and cloned, respectively, into an eukaryotic expressing vector to form TR26 which was restricted to HLA-B51, SH6 which was restricted to HLA-A2. 1, and TS, which had the two aforementioned mini-genes fused in tandem. All of these CTL epitope genes were transfected and endogenously expressed in respective cell lines containing appropriate HLA molecules. The obviously increased expressions of HLA class I molecules were detected in the transfected cell lines. It was demonstrated that the two discrete Plasmodium falciparum epitope genes were effectively processed and presented, and the close proximity of the two epitope genes in one chain as in mini-gene TS did not interfere with the processing and presenting of each epitope gene in corresponding cell line. CONCLUSION: A successful expression and presentation of multiple CTL epitope mini-gene in MHC class I allele specific human cell lines were demonstrated by an in vitro assay, which could be corresponding to the vaccination of CTL vaccines in people with different MHC I molecules. This work also suggested the possibility of constructing a multiple CTL epitope Plasmodium falciparum DNA vaccine that could cover most of Chinese population.

Animals↗