Biomedical subjects

Li Hou

Publications and source records attributed to Li Hou.

21 records · Page 2Linked to original sources

PubMed2002

Application of static and dynamic liquid-phase microextraction in the determination of polycyclic aromatic hydrocarbons.

Two modes of liquid-phase microextraction (LPME), static and semi-automated dynamic, have been developed for the HPLC analysis of polycyclic aromatic hydrocarbons. In static LPME, a small drop (3 microl) of organic solvent was held at the tip of a microsyringe needle and exposed to the sample containing the analytes, permitting extraction to occur. In semi-automated dynamic LPME, a syringe pump was used to automate the repetitive procedure of filling a microsyringe barrel that functioned as a microseparatory funnel, with fresh aliquots of sample, and expelling them after extraction. The factors influential to both techniques such as the type of organic solvent, extraction time, sampling volume, number of samplings, salt concentration and temperature were investigated. Static LPME provided high enrichment (60- to 180-fold) and simplicity. The analytical data exhibited a relative standard deviation range of 4.7-9.0%. Dynamic LPME provided higher (>280-fold) enrichment within nearly the same extraction time (approximately 20 min) and better precision (< or = 6.0%). Both methods allow the detection of polycyclic aromatic hydrocarbons at microg/l levels in water by HPLC. Water samples collected from two rivers were analyzed using the methods, respectively. The results demonstrated that both modes of LPME were fast, simple and accurate.

Chromatography, High Pressure Liquid↗

PubMed2002

[Relationship between lymph node metastasis and the expressions of E-cadherin, N-cadherin, and matrix metalloproteinase in breast carcinoma].

BACKGROUND & OBJECTIVE: There is little ideal predictor available on evaluating the lymph node metastatic potential of breast carcinoma. This study was designed to determine the expression of gene products of E-cadherin (epithelial), N-cadherin (nerve), and matrix metalloproteinase-9 (MMP-9) in breast carcinoma tissue and investigate their association with the invasion and metastasis of breast carcinoma. METHODS: The authors examined the expressions of E-cadherin, N-cadherin, and MMP-9 in 72 cases of breast carcinoma(39 cases with lymph node metastasis and 33 cases without lymph node metastasis) by immunohistochemistry. Multivariable Cox proportional hazards model was used to analyze the patients' prognosis. RESULTS: The average ranks of E-cadherin in lymph node metastasis group and no lymph node metastasis group were 29.19 and 45.14, respectively, with significant difference (P < 0.001). The expression of E-cadherin was correlated inversely with the metastasis of breast carcinoma. The average ranks of N-cadherin and MMP-9 were 40.04 and 42.97 in lymph node metastasis group, and 32.32 and 28.85 in no lymph node metastasis group, both with significant difference (P < 0.05), and these expressions were positively correlated with the lymph node metastasis of breast carcinoma. The patients who had high expression of E-cadherin had a longer survival time. CONCLUSION: Expression of E-cadherin, N-cadherin, and MMP-9 are associated strongly with lymph node metastasis of breast carcinoma. These proteins are indicators of metastasis potential and prognosis of breast carcinoma.

Adult↗

PubMed2002

[Matrix metalloproteinases map of lymphogenous metastasis of hepatocarcinoma cell in mice].

BACKGROUND & OBJECTIVE: Metastasis is the leading cause of tumor-related death, in which lymphogenous metastasis is the most common pattern and also a bridgehead of further metastasis. However, the molecular mechanism of metastasis is uncertain. This study was designed to investigate the correlation between the metastasis of hepatocarcinoma cell(HCC) to lymphnode and matrix metalloproteinases (MMPs) activity and the expression of Fas ligand of tumor cells in lymphnodes. METHODS: The maps of MMPs in supernatants of mouse HCCs with different metastatic potential Hca-F(high potential) and Hca-P cells(low potential) cultured with extract of lymph node, liver or spleen were examined by zymographic analysis. Growth fraction of lymphocytes in lymph nodes of tumor burden mice was detected by flow cytometry. The apoptosis signals of macrophages in lymph nodes were observed with TUNEL staining. The expressions of Fas ligand of Hca-F and Hca-P cells in the mice were examined by immunohistochemistry. RESULTS: With the presence of the extraction of lymph note, the quantity of MMP-9 significantly increased (P < 0.01): in RPMI1640 medium, the quantity of MMP-9 produced by Hca-F and Hca-P were 1256 +/- 157 and 2642 +/- 385, respectively. After the addition of extraction of lymph node, the quantity of MMP-9 increased to 12,403 +/- 894 and 9086 +/- 686, respectively, together with the secretion of a large amount of MMP-2 (Hca-F: 7364 +/- 2001, Hca-P: 2997 +/- 1990) and active MMP-9 (Hca-F: 7297 +/- 1657, Hca-P: 3914 +/- 1253), and the amount of which was also more in Hca-F than in Hca-P cells(P < 0.05). There was no MMPs detected when the extraction of liver and spleen is present. The growth fraction of lymphocytes was as follow: in the Hca-F cells, the proliferating peak of lymphocytes appeared on the 14th day post-inoculation and then decreased rapidly, while in the Hca-P cells, the peak appeared on the 7th day post-inoculation and then kept at a high level. TUNEL staining showed that the positive signals of macrophages were detected around Hca-F cells. The expression of Fas ligand of Hca-F cells was stronger than that of Hca-P cells (P < 0.01). CONCLUSION: The MMPs secretion of Hca-F and Hca-P cell depend on the environment of lymph nodes. The increased expression of Fas ligand protein in Hca-F tumor cells with high lymphogenous metastatic potential in lymph nodes may help tumor cells escape from being killed by host lymphocytes.

Animals↗