Biomedical subjects

Li Gu

Publications and source records attributed to Li Gu.

21 records · Page 2Linked to original sources

PubMed2003

Atomic force microscopy of actin.

Atomic force microscope (AFM) is a powerful and novel tool to investigate the surface and submembranous structures of living cells under physiological conditions at high resolution, and has force measure at nano-Newton level. AFM can image and manipulate samples (single macromolecule, cells, and so on) at very high, sometimes atomic resolution by scanning a fine tip over the surface of interest and detecting physical interactions between the tip and sample. Actin is one of the most important proteins, involved extensively in various cell physiological activities and functions in eukaryotes. The present paper clarified the crucial significance and the enormous applicable prospects of AFM in modern biological sciences by reviewing the usage of AFM in actin study, which can be taken as a good example for expounding almost all functions that AFM owns, and can be utilized in life sciences exploration.

Actins↗

PubMed2003

[Different cytokine profiles in usual interstitial pneumonia and nonspecific interstitial pneumonia].

OBJECTIVE: To study the distribution, the expression and the significance of TGF-beta(1), b-FGF, IL-8, IL-13 and IFN-gamma in different lung tissue compartments in usual interstitial pneumonia/idiopathic pulmonary fibrosis (UIP/IPF) and nonspecific interstitial pneumonia (NSIP). METHODS: Specimens were obtained by open or video-assisted thoracoscopic lung biopsy from patients with UIP (n = 5) and NSIP (n = 8). Control specimens were obtained by surgical lobectomy from patients with primary lung cancer (n = 5). The distribution of these cytokines in lung tissues was observed by semi-quantitative method using immunohistochemical staining. RESULTS: TGF-beta(1), IL-8 and b-FGF were localized in alveolar epithelial cells, alveolar macrophages, and the bronchial epithelium. Overall intensity of TGF-beta(1), IL-8 and b-FGF expression in UIP was stronger in comparison with NSIP. IL-13 was distributed in alveolar epithelial cells, alveolar macrophages and interstitial mononuclear cells. Its expression in UIP was similar to that in NSIP. IFN-gamma was expressed mainly in interstitial mononuclear cells. Its expression in NSIP was stronger than that in UIP. The ratio of IL-13 to IFN-gamma in UIP (2.18 +/- 0.76) was significantly higher than that in NSIP (0.95 +/- 0.28) or that in the control (0.91 +/- 0.16) (P < 0.05, UIP versus NSIP or control), whereas the ratio of IL-13 to IFN-gamma in NSIP was similar to that in the control. In normal lungs, only alveolar macrophages expressed these cytokines. CONCLUSION: The different expression of TGF-beta(1), IL-8 and b-FGF in UIP and NSIP and the balance of IL-13/IFN-gamma may be involved in the different pathogenesis in these two diseases.

Adult↗

PubMed2002

[Inhibiting target gene expression and controlling growth of Epstein-Barr virus transformed cells by antisense RNA transcripts].

BACKGROUND & OBJECTIVES: The latent membrane protein gene (LMP) of Epstein-Barr virus (EBV) was thought to play an important role in the carcinogenesis of nasopharyngeal carcinoma (NPC). In this study, the authors investigated the effects of antisense RNA (AsRNA) on LMP for down regulating at the target gene over expression in EBV transformed lymphoid cells, and set up an antisense system to inhibit LMP expression. METHODS: Constructing the single strand antisense transcription system in vitro, the authors have got large amount of AsRNA. Designing and setting up an antisense tracing system in situ (ATSIS), the authors could observe the living particles of AsRNA/sense RNA duplex dimer. With time lapse phase-contrast microscopy, the agglutination phenotype on living cells was easily detected by MTT test, the inhibition rate on EBV transformed cells was calculated. RESULTS: LMP 1.9 fragment ligated into pGEM vector in reverse orientation have been constructed and produced a plentiful amount of AsLMPmRNA which could incorporated into both B95-8 and C1936 cell lines by endophagocytosis and formed the duplex dimer of As/Sense RNA. This particles have been visualized in situ when labelling 35S isotope by ATSIS. When AsLMPmRNA acted as agents for specific inhibition to LMP over expression, the transform phenotype of cell agglutination have been suppressed and MTT particle formatin was apparently reduced both two EBV tansformed cell lines. CONCLUSION: AsLMPmRNA targets at sense strand have a high effectiveness of down-regulation on EBV-LMP overexpression. This down regulating function of LMP and growth inhibition on transformed cell is demonstrated by the antisenes tracing system in situ (ATSIS). The results provide a clue to overcome the latent EBV infection in human bodies all living long time and to prevent it inducing NPC in high incidence area by antisense strategies.

Agglutination↗