Biomedical subjects

Yan Zheng

Publications and source records attributed to Yan Zheng.

41 records · Page 3Linked to original sources

PubMed2003

[Expression of the metastasis-associated gene 1 in laryngeal squamous cell carcinoma: correlation with cervical lymph node metastasis].

OBJECTIVE: The purpose of study was to examine the mRNA expression levels of the metastasis-associated gene1 (MTA1) in laryngeal squamous cell carcinoma (LSCC), so to evaluate its relationship with metastases. METHODS: Forty-eight surgically resected primary LSCC (16 supraglotti laryngeal carcinomas with cervical lymph node metastasis, 16 supraglotti laryngeal carcinomas with cervical lymph node-negative metastasis, 16 glottic carcinoma with cervical lymph node-negative metastasis) and 16 normal laryngeal mucosa was examined for mRNA expression of MTA1 by reverse transcription-polymerase chain reaction(RT-PCR). RESULTS: The frequency of MTA1 mRNA positive expression in 16 LSCC with cervical lymph node metastasis was 100%, but no expression of MTA1 mRNA was observed in other LSCC with cervical lymph node-negative metastasis (16 supraglotti laryngeal carcinomas and 16 glottic carcinoma) and 16 normal laryngeal mucosa. CONCLUSION: MTA1 gene is strongly related to cervical lymph node metastasis of LSCC, and may serve as a early diagnosis indicator.

Adult↗

PubMed2003

[Research for locating the mitochondrial DNA deletions of aged guinea-pigs].

OBJECTIVE: To locate the mtDNA deletions of aged guinea-pigs. METHODS: By reference to the common law of mtDNA deletions in humans and rats, the possible locations of mtDNA deletions in guinea-pigs were examined by PCR and DNA sequencing. The cochlear Cortis, auditory nerve and brain tissues were harvested and the total DNA was extracted. RESULTS: It was discovered for the first time that there are 4568 bps deletions of mtDNA between nt8636-nt13203 in guinea-pigs. The mtDNA deletion incidence of the aged group was significantly higher than that of the young control group (P < 0.05). CONCLUSION: There exist 4568 bps deletions between CO III and ND5 genes of mtDNA in aged guinea-pigs; mtDNA4568 deletions of guinea-pig possibly contribute to aging.

Aging↗

PubMed2003

[Expression of nuclear factor-kappa B mRNA, inducible nitric oxide synthase and interleukin-6 in nasal polyp and its role].

OBJECTIVE: To evaluate the expression and significance of nuclear factor-kappa B (NF-kappa B) mRNA, inducible nitric oxide synthase(iNOS) and interleukin-6 (IL-6) in the pathophysiology of nasal polyp(NP). METHODS: The specimens from 59 nasal polyps (NP) and 20 inferior turbinates (IT) were studied by in situ hybridization for NF-kappa B mRNA, and by immunohistochemistry for iNOS and IL-6. Tissue sections were observed under optical microscope. RESULTS: NF-kappa B mRNA, iNOS and IL-6 overexpressions were localized mainly to the nasal polyp epithelium, the various inflammatory cells, in submucosal endothelial cells around the vessel and in submucosal glands. The positive frequency of activation of NF-kappa B mRNA was higher in NP (54.24%) than in IT (P < 0.01), whereas the positive frequency of iNOS and IL-6 overexpression were higher in NP (62.71% and 64.41%) than in IT (P < 0.01). Eosinophils and neutrophils in NP were higher than in IT (P < 0.01). CONCLUSION: These results suggest that NF-kappa B, iNOS and IL-6 are strongly correlated with the formation of NP. NF-kappa B, iNOS and IL-6 may act as anti-apoptotic molecules in eosinophils and neutrophils that may be responsible for the recruitment of inflammatory cells, particularly eosinophils, through the initiation of the transcriptional pathway of the related cytokines. NF-kappa B might play a key role in the pathogenesis of NP process and therefore is a potential target for medical treatment and new therapeutic intervention.

Adolescent↗

PubMed2002

Evidence for immune responses to a self-antigen in lung transplantation: role of type V collagen-specific T cells in the pathogenesis of lung allograft rejection.

We have reported that lung allograft rejection involves an immune response to a native protein in the lung, type V collagen (col(V)), and that col(V)-induced oral tolerance prevented acute and chronic rejection. In support of these findings col(V) fragments were detected in allografts during rejection, but not in normal lungs. The purpose of the current study was to isolate and characterize col(V)-specific allograft-infiltrating T cells and to determine their contribution to the rejection response in vivo. Two col(V)-specific T cell lines, LT1 and LT3, were isolated from F344 (RT1(lv1)) rat lung allografts during rejection that occurred after transplantation into WKY (RT1(l)) recipients. Both cell lines, but not normal lung lymphocytes, proliferated in response to col(V). Neither LT1 nor LT3 proliferated in response to alloantigens. LT1 and LT3 were CD4(+)CD25(-) and produced IFN-gamma in response to col(V). Compared with normal CD4(+) T cells, both cell lines expressed a limited V-beta TCR repertoire. Each cell strongly expressed V-beta 9 and 16, but differed in expression of other V-betas. Adoptive transfer of each cell line did not induce pathology in lungs of normal WKY rats. In contrast, adoptive transfer of LT1, but not LT3, caused marked peribronchiolar and perivascular inflammation in isograft (WKY) lungs and abrogated col(V)-induced oral tolerance to allograft (F344) lungs. Collectively, these data show that lung allograft rejection involves both allo- and autoimmune responses, and graft destruction that occurs during the rejection response may expose allograft-infiltrating T cells to potentially antigenic epitopes in col(V).

Animals↗

PubMed2002

Promotion of well-switching to mitigate the current arsenic crisis in Bangladesh.

OBJECTIVE: To survey tube wells and households in Araihazar upazila, Bangladesh, to set the stage for a long-term epidemiological study of the consequences of chronic arsenic exposure. METHODS: Water samples and household data were collected over a period of 4 months in 2000 from 4997 contiguous tube wells serving a population of 55000, the position of each well being determined to within +/- 30 m using Global Positioning System receivers. Arsenic concentrations were determined by graphite-furnace atomic-absorption spectrometry. In addition, groundwater samples collected every 2 weeks for an entire year from six tube wells were analysed for arsenic by high-resolution inductively coupled plasma-mass spectrometry. FINDINGS: Half of the wells surveyed in Araihazar had been installed in the previous 5 years; 94% were privately owned. Only about 48% of the surveyed wells supplied water with an arsenic content below 50 micro g/l, the current Bangladesh standard for drinking-water. Similar to other regions of Bangladesh and West Bengal, India, the distribution of arsenic in Araihazar is spatially highly variable (range: 5-860 micro g/l) and therefore difficult to predict. Because of this variability, however, close to 90% of the inhabitants live within 100 m of a safe well. Monitoring of six tube wells currently meeting the 50 micro g/l standard showed no indication of a seasonal cycle in arsenic concentrations coupled to the hydrological cycle. This suggests that well-switching is a viable option in Araihazar, at least for the short term. CONCLUSIONS: Well-switching should be more systematically encouraged in Araihazar and many other parts of Bangladesh and West Bengal, India. Social barriers to well-switching need to be better understood and, if possible, overcome.

Arsenic↗