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Biomedical subjects

Yang Gao

Publications and source records attributed to Yang Gao.

60 records · Page 4Linked to original sources
PubMed2003

[Molecular mechanism of metastasis inhibition of nasopharyngeal carcinoma cell CNE-2L2 induced by reduction of 6A8 alpha-mannosidase expression].

OBJECTIVE: To study the effect of inhibition of 6A8 alpha-mannosidase expression on adhesiveness among and E-cadherin expression on CNE-2L2 cells, and on metastasis of the tumors from the cells inoculated in nude mice. METHODS: Anchorage-independent adhesion among cells was examined in soft agar culture. E-cadherin expression was studied by immunofluorescence staining, immunohistological staining and RT-PCR. CNE-2L2 cells were subcutaneously inoculated into nude mice. Eight weeks later tumor metastasis was demonstrated by means of histological examination of lung sections. RESULTS: CNE-2L2 cells with suppression of 6A8 alpha-mannosidase expression (AS) became aggregated. E-cadherin expression on wild type cells was very weak. In contrast, it was greatly enhanced on AS cells. The enhancement was detected on both protein and mRNA levels. Lung metastasis of the tumor from inoculated AS cells were heavily inhibited in nude mice. CONCLUSION: Inhibition of 6A8 alpha-mannosidase expression results in enhancement of cell-cell adhesion and of E-cadherin expression on CNE-2L2 cells. Lung metastasis of the tumor grown from AS cell inoculate in nude mice is heavily suppressed.

Animals↗
PubMed2003

[Apply ICA (independent component analysis) to removing power noise from EEG].

Power noise is constantly found in EEG signals; thus the acquisition and analysis of EEG signals can be strongly influenced. Comparison of the efficiencies of four ICA algorithms (Fastica, Extended Infomax, EGLD, Pearson-ICA) and SVD methods in extracting power noise in the EEG signals showed that ICA algorithms appear insensitive to the noise disturbance, whereas the commonly used SVD method does not. By applying the Extended-Infomax ICA with better convergence in this paper, it was demonstrated that the power noise contained in the 16-channel EEG signals of one Alzheimer-disease patient were removed successfully(the lowest signal-noise-ratio for power noise is 0 dB). ICA has a possible important value and prospect in biomedical signal processing, especially in clinical medical engineering.

Algorithms↗
PubMed2002

Enantioselective synthesis of N(alpha)-Fmoc protected (2S,3R)-3-phenylpipecolic acid. A constrained phenylalanine analogue suitably protected for solid-phase peptide synthesis.

Reported herein is the first enantioselective preparation of (2S,3R)-3-phenylpipecolic acid as a conformationally constrained phenylalanine analogue bearing N(alpha)-protection suitable for solid-phase peptide synthesis. Stereochemistries at both the 2- and 3-positions are derived inductively from a single chiral center provided by the commercially available Evans chiral auxiliary, (4S)-4-benzyl-1,3-oxazolidin-2-one. By constraining phi and chi(1) torsion angles, this novel amino acid analogue can serve as a useful tool for the induction of defined geometry in phenylalanine-containing peptides.

Carboxylic Acids↗
PubMed2002

[Significance of COX-2, p53, proliferating cell nuclear antigen and nm23 expressions in gastric cancer and its behavior].

BACKGROUND & OBJECTIVE: Molecular biological studies indicated that abnormal expression of cyclooxygenase-2(COX-2), p53, proliferating cell nuclear antigen(PCNA), and nm23 correlate with the development of gastric cancer, but the relationship between abnormal expression of above gene proteins and the biological behavior of gastric cancer was not yet clear. This study was designed to investigate the relationship between expressions of COX-2, p53, PCNA, and nm23 and the clinicopathological behavior in gastric cancer. METHODS: The expressions of COX-2, p53, PCNA, and nm23 were detected by using immunohistochemical(SP) method. RESULTS: (1) The overexpression rate of COX-2 in gastric cancer was 70.4% (50/71), and the overexpression of COX-2 was correlated to tumor size, gross morphology, histological type, lymph node metastases, and clinicopathological stage of gastric cancer (P < 0.05, or P < 0.01). (2) The overexpression rates of p53 and PCNA in 71 surgically removed specimens from the patients with gastric cancer were 74.6% and 78.9%, respectively. And the expressions of p53 (86.7%) and PCNA (88.8%) in gastric cancer patients with lymph node metastasis were significantly higher than those in patients without lymph node metastasis (53.8% and 61.5%) (both, P < 0.05), respectively. Moreover, expressions of p53(52.2%) and PCNA(60.9%) in stage I + II patients were lower than those(85.4% and 87.5%) in stage III + IV (both, P < 0.05). (3) The low-expression of nm23 in gastric cancer was 71.8%, and its low-expression rate of nm23 in patients without lymph node metastasis(88.5%) and in stage I + II (91.3%) were much higher than those in the patients with lymph node metastasis (62.2%) and in stage III + IV (62.5%) (respectively, P < 0.05). (4) The differences of histological types, depth of invasion, lymph node metastasis and clinical stage were significantly different(P < 0.05 or P < 0.001), between the patients with two or more genes expression of COX-2, p53, PCNA, and nm23 and those with less one gene expression. CONCLUSION: Our results suggest that abnormal expressions of COX-2, p53, PCNA, and nm23 associate with malignant potential, lymph node metastasis and clinical stage, and they might therefore play a role in development of gastric cancer.

Cyclooxygenase 2↗
PubMedDate not supplied

Categorical evaluation of the ocular irritancy of cosmetic and consumer products by human ocular instillation procedures.

The assessment of ocular irritation potential is an important part of safety testing for cosmetic and consumer products. The purpose of this investigation was to examine ocular irritancy levels elicited in humans by various categories of a specific class of cosmetic and consumer products that have a potential to enter the eye inadvertently during use. Test materials assessed belonged to one of seven categories, which included liquid makeup, shampoo, baby wash, mascara, eye makeup remover, powder eye shadow, and facial cleanser. These test materials were evaluated by human ocular instillation, followed by examinations, for which subjective perceptions of irritation were recorded, and component areas of ocular tissues were individually examined for inflammation and for the area and density of fluorescein staining patterns at 30 seconds and at 5, 15, 60, and 120 minutes post-instillation. Subjective and objective ocular irritation scores of 410 eyes were analyzed by product classification. Average score levels were determined for subjective responses, inflammation, and fluorescein staining patterns. This investigation determined that irritation levels of the evaluated test materials varied markedly with respect to product category, type of ocular irritation, and ocular tissue, demonstrating that these factors are important considerations for the prediction of the ocular irritancy of a test material.

Adult↗