Biomedical subjects

Zheng-chang Heng

Publications and source records attributed to Zheng-chang Heng.

5 recordsLinked to original sources

PubMed2006

[Study of rat's p53 gene damage and organ specificity induced by benzidine].

OBJECTIVE: Studying the main target organs and the genetic toxicity mechanism of benzidine. METHODS: SD rats were given benzidine i.p. injection. DNA was extracted from rat's liver, kidney, lung and bladders. Then ss probes RDPCR was used to detect the damaged DNA of exon 7 of p53 gene. RESULTS: Hybridization bands were found in liver, bladder and lung tissues after ss probes RDPCR, while no hybridization bands were found in kidney tissues. CONCLUSION: The result indicates that benzidine can cause the DNA lesions of exon 7 of p53 gene and its major target organs are liver, bladder and lung. The toxicity mechanism of benzidine is probably related to p53 gene damage.

Animals↗

PubMed2006

[Blood leptin, orexins and NPY levels and their relations in obese children].

OBJECTIVE: To investigate the concentration levels of leptin, orexins and neuropeptide Y (NPY) in the blood of obese children, and to analysed the relationship between these substances. METHODS: RIA methods were used to measure the concentrations of leptin, orexinA, orexinB, and NPY in the blood of 98 obese children [BMI: male (29.24 +/- 1.87) kg/mZ, female (28.12 +/- 2.30) kg/m2] and in 104 normal children [BMI: male (20.49 +/- 1.95) kg/m2, female (19.59 +/- 1.51) kg/m2] as the control group. RESULTS: The leptin concentrations in obese children [male (26.00 +/- 14.66) ng/mL; female (33.59 +/- 14.63) ng/mL] were higher than those in the control group [male (6.65 +/- 44.49) ng/mL; female [10.48 +/- 5.52) ng/mL P < 0.013]. The concentrations of plasma orexinA in obes children [male (3.23 +/- 1.86) pg/mL; female (3.38 +/- 1.80) pg/mL] were lower than those in the control group [male (4.52 +/- 1.52) pg/mL; female (4.71 +/- 1.53) pg/mL P < 0.05]; Negative correlations between leptin and NPY were noted in the obesity group (r = -0.302) and the control group (r = -0.310, P < 0.01), while the slopes in the two groups were different (control group -2.969; obese group -0.809). A positive correlation between NPY and orexinA was noted (r = 0.207, P < 0.05). The fluctuation range of orexinA in obese children was markedly narrowed when compared with that in the control group. CONCLUSION: The concentration level of peripheral orexinA and leptin in the obese and non-obese children change inversely. The obesity in children correlates with the concentrations of orexinA, leptin, NPY as well as with their interactions.

Adolescent↗

PubMed2005

Mutation analysis of HOXD13 gene in a Chinese pedigree with synpolydactyly.

OBJECTIVE: To study the clinical features and to identify homeobox D13 (HOXD13) gene mutation of the affected individuals in a Chinese synpolydactyly (SPD) kindred. METHODS: Clinical data and peripheral blood samples of SPD family members were obtained through field investigation. For every member of this pedigreeìthe fragment containing mutational hot spots of HOXD13 was amplified by PCR for mutation screening. To examine whether there is any other mutation within coding sequence of HOXD13, exon 1 and exon 2 of HOXD13 were also amplified by PCR. All the amplified fragments were electrophoresed on 2% agarose gels and then the mutant fragments were electrophoresed on 5% polyacrylamide gels to be separated. Purified PCR products of normal and selected mutant alleles were directly sequenced. RESULTS: Comparing the HOXD13 coding sequence of the affected individuals with HOXD13 sequence in the GenBank and with that of the unaffected, an inserted segment coding 8 alanine residues within HOXD13 was found segregating with the disorder. This mutation is also termed polyalanine expansion. The 8-alanine expansion can be interpreted as a reduplication of normal alanines 5-12. CONCLUSION: The results suggest that synpolydactyly in this kindred may be caused by polyalanine expansion in HOXD13.

Base Sequence↗

PubMed2005

[Application with single-stranded probes in randomized terminal linker-dependent PCR].

OBJECTIVE: Preparing single-stranded (ss) probes in place of double-stranded (ds) probes to improve the hybridization efficiency and specificity of randomized terminal linker-dependent PCR (RDPCR). METHODS: Using asymmetric PCR and single-primer PCR to prepare ss probes of extron 7 of p53 gene in rat, then comparing the results hybridized with ss probes and ds probes. RESULTS: Preparation of ss probes by asymmetric PCR and single-primer PCR gets success. Hybridization results showed that the ss probes could get better signals and less noise than ds probes. CONCLUSION: In comparison with ds probes, the application of ss probes can increase the hybridization sensitivity and specificity of RDPCR.

Animals↗

PubMed2005

[Establishment and characterization of the lung cancer A549 cell stains with down-regulated expressed HOGG1 genes].

OBJECTIVE: To establish lung cancer A549 cell strains with down-regulated expressed HOGG1 genes and study its biological characteristics. METHODS: The eukaryotic expression vectors with genes of hammerhead ribozyme targeting human 8-oxoguanine DNA glycosylase 1 (HOGG1) mRNA were transfected into A549 cells by liposmes, and then were screened by G418 till stable cell strains were constructed. The positive recombinants were identified by RT-PCR to amplify NEO genes. The efficacy of inhibition was tested by RT-PCR. Furthermore, morphology, survival curves, cell cycle, cloning efficiency grow in the soft agar and the activity of superoxide dismutase (SOD) were investigated. RESULTS: The HOGG1-down-regulated expressed A549 cell strains were obtained after G418 selection and NEO genes identification. The mRNA expression level of HOGG1 genes in the down-regulated expressed cells named A549-R were decreased 61.5% than in the untransfected cells A549 (P < 0.05). There was no significant difference between A549-R cells and A549 cells in morphology, the population doubling time and cell cycle. The numbers of clones in the soft agar of A549-R cells was decreased nearly to 50% than of A549 cells (P < 0.05), but the activity of SOD was increased obviously (P < 0.05). CONCLUSION: The lung cancer A549 cell strains with down-regulated expressed HOGG1 genes by silencing and incision of ribozyme were successfully established. Its biological characteristics have no significant changes in most of indexes.

Adenocarcinoma↗