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Biomedical subjects

J Yang

Publications and source records attributed to J Yang.

At least 361 records · Page 20Linked to original sources
PubMed2001

[Protective effect of tanshinone on injured cultured PC12 cells in vitro].

OBJECTIVE: To investigate the protective effects of tanshinone on ischemia-like injury models. METHOD: Six ischemia models including hypoxia, hypoglucose, oxidant injury, calcium overload, nitric oxide neurotoxicity and glutamic acid injury were used to assay the anti-ischemic roles of tanshinone in cultured PC12 cells, by using morphological examination, MTT staining and LDH measurement. RESULT: It was found that 3. 125-200 microliters.ml-1 tanshinone possessed obvious protective effects on PC12 cells from six ischemia-like injury models. Tanshinone could increase the number of life cells and decrease LDH activity significantly, particularly in hypoxia and caffeine injured model. CONCLUSION: Tanshinone protected PC12 cells from all injury models effectively in vitro. Its action may mainly focus on inhibiting development of the primary period of ischemia injury and calcium overloading injury.

Abietanes↗
PubMed2001

[Study of the changes and effect of VEGF and bFGF in early stage of maxillofacial blast injury in rabbits].

OBJECTIVE: The aim of this study is to determine the content of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in the wound fluid during maxillofacial soft tissue blast injury, and to evaluate their effects on angiogenesis of wound healing. METHODS: The rabbit model of maxillofacial blast injury was made by KTY-04 blasting cap. The content of VEGF and bFGF in wound fluid which was collected by using polying alcohol (PVA) sponge, were detected by ELISA. The distributions of VEGF and bFGF in the wound tissue were observed by using the techniques of in situ hybridization and immunohistochemistry. RESULTS: In the wound fluid of maxillofacial blast injury, the content of VEGF was rising steadily at the first week after injury. Comparing with natural sera, it showed difference from the first day after injury, and showed obvious different from the third day (P < 0.01), on which the content was 2.9 ng/ml +/- 2.7 ng/ml. It reached the peak on the seventh day after injury. The bFGF level in wound fluid was 565 pg/ml +/- 436 pg/ml, the peak value was gained at the sixth hour after injury. In the following days, it declined close to the serum level three to five days after injury, and then moved up slightly on the seventh day after injury. The expression of VEGF was located in epithelial cells, vascular endothelial cells and some chronic inflammatory cells. The mRNA transcription of bFGF was present in fibroblasts, endothelial cells and macrophages. CONCLUSION: VEGF and bFGF take part in two angiogenic cascades with synergistic action in maxillofacial blast injury. The bFGF stimulates the initial angiogenesis and induces the production of VEGF. The subsequent and more prolonged angiogenic stimuli can be mediated by VEGF.

Animals↗
PubMed2001

[The optimal concentration of drinking water in eastern Guangdong].

OBJECTIVE: The objectives were to explore the optimal concentration of drinking water in Eastern Guangdong and to provide information for the health administrative department to set up the criteria for fluoride concentration. METHODS: Totally 1237 9-17 and 35-44 years old residents in Eastern Guangdong who drinking water containing 0.1-2.5 mg/L fluoride were recruited to investigate the occurrences of dental caries and dental fluorosis. Their background information and perceived appearances of teeth were also recorded. RESULTS: The major factor influencing dental fluorosis was fluoride concentration in drinking water. Dental caries decreased when the fluoride concentration increased but dental fluorosis also increased at the same time. It was showed by calculation that the Dental Fluorosis Index would be 0.4 and 0.6 when the fluoride concentration was 0.57 mg/L and 0.7 mg/L respectively. The acceptation to the severity of dental fluorosis among the study subjects was in accordance with the Dean's criteria. CONCLUSION: It suggests that the optimal fluoride concentration in Eastern Guangdong is 0.57 mg/L and should not exceed the upper limit of 0.7 mg/L.

Adolescent↗
PubMed2001

[Expression of bcl-2 and Bax genes in facial neurons and their regulation of neuron apoptosis following facial neurotmesis in rats].

OBJECTIVE: The aim of this study is to investigate the relationship between the expression changes of bcl-2 and Bax genes and their functions in facial neuronal apoptosis after amputating the facial nerve. METHODS: Rats were randomized into two groups, including the experimental and the control group. The changes of expression of bcl-2 and Bax genes in the facial neurons and facial neuronal apoptosis were observed after the facial nerve amputation using the methods of ABC immunohistochemical staining and TUNEL. RESULTS: The expression of bcl-2 and Bax genes and the apoptosis of facial neurons were significantly higher in the experimental group than those of the control group from the 3rd to 21st day after amputation, but the bcl-2/Bax significantly decreased compared with that of the control group. CONCLUSION: This indicated that bcl-2 and Bax might play an important regulation role in the process of facial neurons apoptosis following facial nerve amputation.

Animals↗
PubMed2001

[Construction of eukaryotic expression plasmid pcDNA3-gtfB expressing glucosyltransferase B of Streptococcus mutans].

OBJECTIVE: Glucosyltransferase (GTF) of Streptococcus mutans is considered as a cariogenic virulence factor due to its ability to synthesize glucan, which facilitate sucrose-depended adherence and cell-to-cell accumulation of bacteria. In this study, gtfB, the target gene fragment which encodes multiple catalytic sites and antigen epitopes of GTF, was recombined into eukaryotic expression vector pcDNA3. The feasibility of the recombination plasmid pcDNA3-gtfB used as gene vaccine will be investigated in further study. METHODS: The target gene fragment gtfB (904-4578 bp) was obtained by standard PCR amplification while genome DNA of streptococcus mutans GS-5 was used as template. Then the PCR products were extracted and purified from low-melting temperature agarose. The gtfB and plasmid pcDNA3 were cut by Kpn I, Xho I, and the digested products were extracted and purified again for recombination. The purified gtfB and plasmid pcDNA3 were recombined by T4 DNA ligase, ligation products were transformed into competent cell, Escherichia coli JM109. Transformed colonies were screened by Ampr LB plate, then recombined plasmids were isolated and identified by restricted endonuclease cutting and Sanger dideoxy DNA sequencing. RESULTS: Identified by agarose gel electrophoresis, the target gene-gtfB obtained PCR amplification had the same molecular size (36 kb) as predicted. It was indicated that recombined plasmids contained inserted gtfB gene fragment by restricted endonuclease cut analysis, the sequencing data also indicated that inserted gtfB gene had correct DNA sequence and orientation according to DNA sequence of Streptococcus mutans GS-5 (gene bank M17361). CONCLUSION: Inserted gene-gtfB of recombined plasmid pcDNA3-gtfB encoded multiple catalytic sites and epitopes. It was proved that these epitopes had high immune antigenicity and that antiserum could significantly inhibit the synthesis of water-insoluble glucans and water-soluble glucan. In vitro adherence experiment also indicated that it could inhibit streptococcus mutans adherence to saliva-coated hydroxyapatite. Vector pcDNA3 was high expressing eukaryotic vector, and could stimulate antigen-representing cell. It was suggested that recombined plasmid pcDNA3-gtfB had high immune antigenicity and immune responsiveness, and this supported its use as gene vaccine candidates in the development of anti-caries vaccines.

Dental Caries↗
PubMed2001

[Observation of the biological characterizations of nasopharyngeal epithelial cells by EB virus infection in early phase of immortalization].

The multi-stage cell model of the nasopharyngeal carcinoma development in vitro by Epstein-Barr virus transformation is beneficial for the elucidation of the mechanism of nasopharyngeal cancer. To observe the biological changes of primary human nasopharyngeal epithelial cells in early phase of immortalization, in this study, we have detected the morphological changes and the expression profile of senescence-associated beta-galactosidase (SA-beta-Gal) in primary culture. In addition, the expression of EB virus latent membrane protein 1 (LMP1) and the growth curve of primary cells were also detected. Our results showed a low percentage of cells infected with EB virus expressing SA-beta-Gal activity at the late primary culture. In morphology, the cells also formed multilayer foci, and the cell population doubling time was showed. These results demonstrated that the nasopharyngeal epithelial cells by EB virus infection have passed through the senescence and entered the early phase of immortalization. These cells have some of the transformed characteristics. Our results provided the data for further study on the mechanism of immortalization and the establishment of human nasopharyngeal epithelial cell line.

Cell Transformation, Viral↗
PubMed2001

[Epstein-Barr virus latent membrane protein 1 induces the telomerase activity in human nasopharyngeal epithelial cells].

Telomerase activation has been linked to cell immortalization in vitro and tumorigenicity in vivo. In this study, for the first, we reported that Epstein-Barr virus activated the telomerase activity of human nasopharyngeal epithelial cells in the early stage of immortalization as tested by the PCR-ELISA. The telomerase activity in nasopharyngeal epithelial cells was only observed in presenescent cells. It was implicated that Epstein-Barr virus induced the escape of nasopharyngeal epithelial cells from senescence via the activation of telomerase. We further showed that telomerase activation in infected cells was dependent on the protein level of latent membrane protein 1 (LMP1) encoded by Epstein-Barr virus using a Tetracycline regulatory cell line expressing LMP1, pTet-on-LMP1-HNE2. The activity of telomerase in nasopharyngeal cells was decreased when the protein level of LMP1 was blocked by antisense LMP1 plasmid DNA. And the activity of telmerase was also related to the carboxyl terminus of LMP1. It was implicated that the ability of Epstein-Barr virus to suppress senescence is associated with telomerase activation by LMP1.

Cell Transformation, Viral↗
PubMed2001

[An analysis on the forearm bone mass density of rural female and the environmental risk factors].

The distribution of distal and proximal forearm bone mass densities (BMD) with age was discribed and the environmental risk factors of rural female analyzed. A group of 1432 rural female aged 15 and over were sellected. Their demographic characteristics, living and eating habit were obtained by standardized questionnaire. The distal and proximal forearm bone mass density were measured by peripheral dual-energy X ray absorptionmetry (pDEXA). The results showed that the distal and proximal forearm BMDs were increased with age before age 25 and 30 respectively, and reached the peak value at age 30-35. The distal forearm bone density decreased significantly at age 40 while the proximal forearm BMD decreased at age 45. Bone loss rate of the two bone sites was increased significantly at age 50 and reached the peak value at age 55-60. Only the the density of proximal forearm bone, and the year of menopause was the main cause of low bone density. Body weight was the positive factor for bone density at age less than 60. Height only positively affected the proximal forearm bone of those at age 30-45. More ever, drinking tea, parity and educational status may affect distal forearm bone in certain age group while parity, educational status, occupation and marital status were possible risk factors of proximal forearm BMD. It is concluded that environmental risk factors of BMD varied with bone site and age. The prevention of low BMD must rely on subject's age and bone site. The surveillance of low bone density must put the emphasis on spony bone.

Adult↗
PubMed2001

[Screening and sequence analysis of the adult stage-specific gene of Trichinella spiralis].

OBJECTIVE: To obtain the sequence of the adult stage-specific gene of Trichinella spiralis. METHODS: An adult T. spiralis cDNA library was screened using an adult T. spiralis stage-specific probe. The gene sequence was analyzed by DNAstar software and GenBank database. RESULTS: A cDNA clone of 1,629 bp was obtained by screening the library with an adult stage-specific probe. The clone contained one open reading frame composed of 1,464 bp encoding 487 amino acids. GenBank searching revealed that no identical cDNA was found. Two zinc fingers located at the positions within amino acids 207-270. Some possible antigen epitopes were predicted within the amino acids 52-64, 108-116, 137-163 and 226-260. CONCLUSION: A novel stage-specific gene of adult T. spiralis encoding the protein containing certain predicted antigen epitopes was obtained.

Amino Acid Sequence↗
PubMed2001

[Random amplified polymorphic DNA analysis of Cryptosporidium species and strains].

OBJECTIVE: To analyse the genetic heterogeneity of 8 isolates of Cryptosporidium belonging to three species (Cryptosporiduim muris, Cryptosporiduim parvum and Cryptosporidium meleagridis) using RAPD technique. METHODS: DNA extracts of the 8 isolates were amplified by PCR using 26 out of 200 primers. The amplified products were separated by agar electrophoresis followed by staining with ethidium bromide. RESULTS: RAPD analysis revealed; 1. Obvious differences among species were found, the average genetic distance being 7.037; 2. Certain differences among different isolates of the same species were found, the average genetic distance being 5.162. CONCLUSION: RAPD could differentiate the common and respective gene fragments of the 8 isolates of Cryptosporidium.

Animals↗
PubMed2001

[Genotypes of merozoite surface protein 2 of Plasmodium falciparum in different malaria endemic areas].

OBJECTIVE: To determine the genotypes and distribution of MSP2 of Plasmodium falciparum isolates in Yunnan and Hainan provinces, China. METHODS: The central polymorphic region of MSP2 allele was amplified by the nested PCR for genotyping of P. falciparum. RESULTS: The higher degree of polymorphism of MSP2 of P. falciparum was observed in Yunnan and Hainan. Distribution and allele frequencies differed in both provinces, indicating considerable geographical heterogeneity of parasite populations. The mixed infection of different allele-type and multiplicity of infection was more frequent in Hainan than in Yunnan. CONCLUSION: There were obvious differences in the distribution and frequencies of MSP2 alleles between Yunnan and Hainan endemic areas. MSP2 is suitable to be used as a marker gene for the genotyping of P. falciparum infection.

Alleles↗
PubMed2001

[Effect of conventionally prepared rabbit serum on human umbilical vein endothelial cell-304].

OBJECTIVE: To study the effect of conventionally prepared rabbit serum, usually used in the field of serum pharmacology of TCM, in various concentration on cultured system of human umbilical vein endothelial cell (VEC)-304 cell line. METHODS: Prepared conventionally from healthy rabbit, the effect of uncontaminated and nonhemolytic serum of six concentrations (5%, 10%, 20%, 40%, 60% and 80%) on VEC-304 cells was observed using parameters such as cell morphologic examination, trypan blue exclusion test, methyl thiazolyl tetrazolium (MTT) test, lactate dehydrogenase (LDH) and angiotensin-converting release test. RESULTS: Serum of 5% and 10% concentration showed no effect in all the above-mentioned tests. Serum of 20% concentration also showed no effect in the tests except for LDH releasing (P < 0.01). But when the concentration of serum reached up to 40% or above, distinct cytotoxicity and serious injury appeared in a dose-dependent manner. CONCLUSION: High concentration of conventionally prepared rabbit serum could injure the incubated cell. Therefore, in order to lower the background effect of serum as far as possible in TCM serum pharmacological study, the cytotoxicity of rabbit serum should be tested first of all.

Animals↗
PubMed2001

[Effects of 18 alpha-glycyrrhizic acid on rat liver cytochrome P450 isoenzymes and phase II transferase].

AIM: To study the effect of 18 alpha-glycyrrhizic acid (18 alpha-GL) on hepatic microsomal drug metabolizing enzymes in rats. METHODS: 18 alpha-GL (12.5, 50.0 mg.kg-1.d-1) were given i.p. to male Wistar rats for 3, 6 or 12 consecutive days. The rats were sacrificed 24 h after the last dose and the liver microsomes were prepared for analysis of cytochrome P450 (CYP) isozymes and phase II transferase activites. RESULTS: Aniline hydroxylase (CYP2E1) activities in the rats treated with 18 alpha-GL (12.5, 50.0 mg.kg-1) for 6 days decreased dose-dependently by up to 53.2%; For 3, 6 or 12 days 7-ethoxyresorufin O-deethylase (CYP1A1) activities in the rats of 50 mg.kg-1 dose group decreased time-dependently by 17.6%, 38.3% and 47.3%, respectively; Erythromycin N-demethylase (CYP3A) activities was significantly inhibited from 23.1% to 34.3%. UDP-glucuronosyltransferase activities toward 7-hydroxy-4-methylcoumarin significantly increased ranging from 19.3% to 29.9%. UDP-glucuronosyltransferase activities toward 4-phenylphenol in the rats treated with 18 alpha-GL (12.5, 50.0 mg.kg-1) for 6 days increased by 45.9% and 70.3%. Glutathione S-transferase (GST) activities in the rats treated with 18 alpha-GL (12.5, 50.0 mg.kg-1) for 6 days increased by 13.7% and 48.3% in dose-dependent manner. CONCLUSION: 18 alpha-GL inhibited rat liver microsomal cytochrome P450 while induced phase II transferase.

Animals↗
PubMed2001

[Correlation of tumor microvessel density with prognosis in laryngopharyngeal malignant melanoma].

OBJECTIVE: To investigate the relationship between microvessel density and clinicopathology, as well as the prognosis in pharyngo-laryngeal malignant melanoma. METHODS: Specific endothelial cell markers with immunohistochemistry and microvessel density with morphometry in 28 cases of laryngopharyngeal malignant melanoma. RESULTS: There was no correlation between the microvessel density (MVD) and the tumor size, Clark grade, as well as Breslow grade; however, significant correlation was found between the MVD and the AJC's grade, as well as the proliferating cell nuclear antigen (PCNA) labelling index. Microvessel counts were associated with overall survival by Kaplan-Meier analysis. An average vessel count of less than 36.5 (x 200) suggested a better survival, but a higher vessel count of more than 36.5 (x 200) showed a trend to worse the overall survival. CONCLUSION: The results suggest a significant relationship between MVD and prognosis; moreover, MVD may be a useful prognostic indicator in laryngopharyngeal malignant melanoma.

Adult↗
PubMed2001

[Human papilloma virus infection and expression of p16 protein in laryngeal papilloma and laryngeal carcinoma].

OBJECTIVE: To evaluate the role of human papilloma virus (HPV) infection and inactivation of p16 gene in laryngeal papilloma (LP) and laryngeal squamous cell carcinoma (LC). METHODS: HPV consensus primers direct in situ polymerase chain reaction (ISPCR) and immunohistochemical method were applied to detect the presence of HPV genomes (1, 6, 8, 11, 13, 16, 18, 30, 31, 32, 33, 45, 51) and the expression of p16 protein respectively in 93 cases of formalin-fixed, paraffin-imbedded specimens, which contained 46 cases of LPs [adult-onset laryngeal papilloma (ALP) 21, juvenile-onset laryngeal papilloma (JLP)25], 26 cases of LCs, 6 cases of normal tissues adjacent to carcinoma, and 15 cases of vocal noduli. RESULTS: (1) The difference of positive rates of HPV-DNA in JLP group (84%, 21/25) and other groups were statistically significant (chi 2 test, P < 0.05). The difference of positive rates of HPV-DNA in ALPs(38.1%, 8/21), in LCs(19.2%, 5/26), in vocal noduli(0%, 0/15), and in normal tissues adjacent to carcinoma(0%, 0/6) were not significant statistically (chi 2 test or Fisher's exact probability test, P > 0.05). (2) The positive rates of expression of p16 protein in ALP group(57.1%, 12/21) and LC group(38.5%, 10/26) were significantly lower than that in vocal nodule group(93.3%, 14/15), in JLP group(88%, 22/25), and in normal tissues adjacent to carcinoma group (100%, 6/6) (chi 2 test or Fisher's exact probability test, P > 0.05). There were no significant differences of positive rates of expression of p16 protein between ALP group and LC group, and between JLP group and vocal nodule group (chi 2 test, P > 0.05). (3) In LPs, the difference of positive rates of p16 protein expression between HPV positive cases and HPV negative cases was significant statistically (chi 2 test, P < 0.05). In LCs, there was no difference in p16 protein expression rate between the two teams(Fisher exact probability test, P > 0.05). CONCLUSION: The pathogenesis of JLP is closely associated with HPV infection and not associated with the inactivation of p16 gene. Conversely, the pathogenesis of ALP and LC is associated with the inactivation of p16 gene and not associated with the HPV infection.

Adult↗
PubMed2001

[ACh and ATP-induced current in isolated outer hair cells and Deiters' cells of guinea pig cochlea].

OBJECTIVE: To determine ACh- and ATP-induced currents in isolated outer hair cells of guinea pig cochlea, respectively. METHOD: The whole-cell patch-clamp technique was used to investigate potential and concentration dependence of ACh- and ATP-induced ion currents. RESULTS: ACh(100 mumol/L) induced an early inward current followed by a late outward current when the cells were voltage-clamped at -70 mV. Only outward current occurred when potential was over -60 mV and its reversal potential was (-80 +/- 5.61) mV(n = 6). When depolarization protocols were applied, amplitude of inward currents activated by ATP(100 mumol/L) decreased and reversed at (3.2 +/- 0.23) mV(n = 8). Ion currents activated by ATP (100 mumol/L) were also recorded from isolated Deiters' cells. CONCLUSION: ACh-induced outward current was carried by K+ and ATP-induced inward current was through non-selective cations channel. Effects of ACh and ATP on OHCs were voltage dependent.

Acetylcholine↗
PubMed2001

Externalization and internalization of cardiac endothelin receptors during different phases of sepsis in rat.

OBJECTIVE: To study the redistribution of endothelin-1 (ET-1) receptors in two subcellular organelles, the sarcolemmal membrane and the light vesicle, of rat heart during the progression of sepsis. METHODS: Sepsis was induced by cecal ligation and puncture (CLP). ET1 receptor was assayed by using [125I]-ET1 binding. Marker enzyme activities, protein yield, and dry-to-wet weight ratio of cardiac membranes were measured. RESULTS: Septic rat heart exhibited two distinct phases: an initial hyperdynamic phase( 9h after CLP; early stage of sepsis) followed by a hypodynamic (18h after CLP, late stage of sepsis) phase. [125I]-ET1 binding study showed that during early stage of sepsis, the B(max) of ET1 receptors was increased by 30% in sarcolemma but decreased by 19% in light vesicles, while during late stage of sepsis, the B(max) was decreased by 24% in sarcolemma but increased by 38% in light vesicles. The total binding of sarcolemma and light vesicles was increased by 25% during early stage of sepsis but decreased by 17% during late stage of sepsis. CONCLUSIONS: These data indicated that ET1 receptors in the rat heart were externalized from light vesicles to sarcolemmal membranes during early hyperdynamic phase while internalized from surface membranes to intracellular compartment during late hypodynamic phase of sepsis.

Animals↗