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X Lei

Publications and source records attributed to X Lei.

At least 37 records · Page 2Linked to original sources
PubMed1999

[The expression of suppressor gene p16, p21 and p53 in nasopharyngeal carcinoma].

OBJECTIVE: To evaluate the roles of p16, p21 and p53 protein expression in nasopharyngeal carcinoma (NPC). METHOD: The SP immunohistochemical method was used to detect the expression of p16, p21 and p53 protein in 116 cases of NPC and 15 cases of non-tumour nasopharyngeal tissue. RESULT: 1. The positive expression rates of p16, p21 and p53 protein were 64.7%, 45.7% and 90.5% in NPC respectively. There were significant differences between NPC and non-tumour group (P < 0.05). 2. The expressive rate of p16 protein was 70.6% in non-keratinizing type, 44.8% in undifferentiated type (P < 0.05). 3. The positive expression of p21 was correlated with the expression of p16 and p53. CONCLUSION: Low expressions of p16 and p21 protein may play an important role in carcinogenesis of NPC, and that of p16 has some relation to cell differentiation of NPC. p16 protein may co-operate with p21 protein in development of NPC. p21 protein is probably not produced by stimulating wild-type p53 protein.

Adult↗
PubMed1999

[Preparation and evaluation of new ion-exchange chromatographic stationary phase for the use in high performance liquid chromatography].

A new method for the bonding of diethylamine(DEA) on the surface of silica to prepare novel hydrophilic packings for HPLC has been studied. After allyl glycidyl ether being synthesized, the Si-DEA anion-exchange bonded phase was prepared by the reaction of the double bond in allyl group with Si-H silica. The bonded phases obtained were characterized by elemental analysis, diffuse reflectance infrared Fourier transform(DRIFT) spectroscopy and HPLC evaluation. The methods were used for both porous silica and monodisperse non-porous silica. The contents of carbon, hydrogen and nitrogen of porous Si-DEA packing (MPS-DEA) were 3.31%, 0.95% and 1.34% respectively and those of monodisperse non-porous Si-DEA packing (NPS-DEA) were 2.55%, 0.97% and 0.96% respectively. The diethylamine absorption peak can be observed at 2970 cm-1 from the Si-DEA silica DRIFT spectrum. These data revealed that the diethylamine had been bonded on MPS-DEA and NPS-DEA packings. In HPLC tests, nucleotides and nucleosides such as cytosine, uracil, cytidine-5'-monophosphate, adenosine-5'-monophosphate, inosine-5'-monophosphate and guanosine-5'-monophosphate were satisfactorily separated on the porous anion-exchange packing (MPS-DEA), and a group of proteins (lysozyme, ribonuclease, ovalbumin, bovine serum albumin, insulin and gamma-globulin) were separated within 15 minutes successfuly. All test results indicated that the new method for preparing better anion-exchange silica packings is effective for both porous silica and monodiperse non-porous silica.

Chromatography, High Pressure Liquid↗
PubMed1998

The conditional binomial test revisited for clinical trials.

McNemar's test is used to test the hypothesis that one treatment is better than another in a matched-pair design for binary outcomes. The conditional binomial test in such a matched-pair design is the exact McNemar test. However, in many clinical trials, one wants to establish equivalency between two treatments. We discuss how to use a conditional binomial test to establish equivalency between two treatments in a matched-pair design. Sample size and power determination for each conditional binomial test are calculated. Some statistical properties of the tests are analyzed through Monte Carlo simulation.

Binomial Distribution↗
PubMed1998

[Anti-invasion activity of several plant-originated anticancer drugs with different mechanism of action].

The antitumor and anti-invasion activities of taxol, harringtonine, homoharringtonine and camptothecin on highly metastatic melanoma B16-BL6 and human fibrosarcoma HT-1080 cells were reported in this paper. Results demonstrated that taxol, harringtonine, homoharringtonine and camptothecin exhibited significant inhibition of cell growth of B16-BL6 and HT-1080 cells. Taxol, harringtonine and homoharringtonine were also found to be effective for the inhibition of cell invasion and migration of B16-BL6 cells, but camptothecin showed basically no effect at the indicated concentration.

Animals↗
PubMed1998

[Comparison of roxithromycin bioavailability of a conventional and a dispersible tablet formulation].

Following oral administrations of a single dose of 150 mg roxithromycin dispersible tablet (formulation A, a new formulation for clinical trial) and conventional tablet (formulation B, purchased from the market) to each of 10 healthy male volunteers in a randomized crossover design, the plasma levels of active drug at different times were determined by a microbial assay with Micrococcus luteus CMCC (B) 28001 and the plasma concentration-time profiles were obtained. The Tmax values of formulation A and B obtained were 1.7 +/- 0.9 and 3.7 +/- 1.6 h, the Cmax values were 4.97 +/- 1.17 and 2.04 +/- 1.26 micrograms.ml-1 and the AUC0-->infinity values were 62.2 +/- 11.9 and 35.0 +/- 16.9 micrograms.h.ml-1, respectively. Surprisingly, the relative bioavailability of formulation B was found to be only 59.8% +/- 32.6% (P < 0.01). The low bioavailability of the latter formulation was attributed to poor release of roxithromycin in the gastric site, which was proposed as a key factor to influence drug absorption. Other related factors were also discussed.

Adult↗
PubMed1998

[High-level expression of human immunodeficiency virus type 1 gp120 protein in E. coli].

In order to improve protein expression and to produce good and cheap diagnostic antigen, the gene fragment (560bp) in N-terminal of gp120 of HIV-1 LAV strain was amplified by PCR. After digested by EcoR I and Sal I, the fragment was cloned into a high-level expression vector pET28a. The recombinant plasmid pET/120 transfecting BL21 (DE3) produced the protein with high-level expression in the host cell BL21(DE3), which was further proved having good antigenicity and high specificity by indirect ELISA and Western-blot assay. The protein expressed was about 50% of the total bacterial protein by SDS-PAGE electrophoresis test. It was highly expressed in the prokaryotic expression system.

Cloning, Molecular↗
PubMed1997

[Circadian rhythm of PGE2 level in plasma and condylar cartilage of young growing rats].

This paper reports the circadian rhythm of PEG2 level in plasma and condylar cartilage of young frowing rats. The samples were measured at 0:00, 4:00, 8:00, 12:00, 16:00, and 20:00 respectively. The count of PGE2 were determined by RIA and analysed with simple Cosinor and coordination. The results revealed: (1) The levels of PGE2 in plasma and condylar cartilage of young growing rats fluctuated in strong circadian rhythm; (2) The rhythm of PGE2 in plasma between 16:00 and 24:00 was significantly different from that between 4:00 and 12:00, so for analysing PGE2 level in plasma, one should proper sampling time or adjust it to circadian rhythm; (3) The circadian rhythm of PGE2 in condylar cartilage could provide important reference for reatments in dentistry and orthopaedics.

Animals↗
PubMed1996

Detection and localization of tumor necrosis factor-alpha in WHHL rabbit arteries.

Tumor necrosis factor-alpha (TNF-alpha) is known to be a secretory product of activated macrophages. TNF-alpha activates endothelial cells, stimulates angiogenesis and induces proliferation of smooth muscle cells (SMCs). Therefore, TNF-alpha has been suggested to be actively involved in the inflammatory events associated with atherosclerosis. Previous ultrastructural and immunocytochemical studies have shown that macrophages as well as SMCs are constituents of atherosclerotic lesions in the Watanabe heritable hyperlipidemic (WHHL) rabbit. Recently, we have shown that TNF-alpha mRNA levels in aorta of 18-month-old WHHL rabbits were significantly higher than that of 6-month-old WHHL rabbits and New Zealand White (NZW) rabbits by quantitative RT-PCR [1]. However, it remains unclear as to the cell type(s) responsible for the increased TNF-alpha mRNA levels in atherosclerotic lesions. In this study, we provided evidence showing the expression of the TNF-alpha gene in the medial SMCs as well as cells of intimal lesions in arteries of WHHL rabbits by in situ transcription (IST). TNF-alpha protein was also detected in the cytoplasm of the intimal and medial SMCs and macrophages by immunocytochemistry using a monoclonal antibody against rabbit TNF-alpha. In contrast, the expression of TNF-alpha mRNA and protein can not be detected in the arteries from healthy New Zealand White (NZW) rabbits. Our results suggest that the expression of TNF-alpha in both intimal and medial SMCs and macrophages is associated with the progression of atherosclerosis.

Animals↗
PubMed1996

Measurement by quantitative reverse transcription-polymerase chain reaction of the levels of tumor necrosis factor alpha mRNA in atherosclerotic arteries in Watanabe heritable hyperlipidemic rabbits.

Tumor necrosis factor-alpha (TNF-alpha), produced by activated monocytes and other cells, has been proposed as a mediator of importance in atherosclerosis. In this study, we use a newly developed technique, quantitative reverse transcription-polymerase chain reaction (RT-PCR), to measure the mRNA levels of TNF-alpha in arteries of Watanabe Heritable Hyperlipidemic (WHHL) rabbits in relation to the progression of atherosclerosis. Co-amplification of known amounts of TNF-alpha RNA and TNF-alpha internal control RNA indicated that the quantitative RT-PCR method was quite reliable, with a < 5% difference between TNF-alpha mRNA levels deduced from the standard curve and actually loaded TNF-alpha mRNA. As another control, TNF-alpha mRNA levels in lipopolysaccharide-induced (LPS-induced) and uninduced monocytes were measured, and a 9.3-fold increase in the TNF-alpha mRNA levels was observed in LPS-induced monocytes. TNF-alpha mRNA levels in the aortic arches of healthy New Zealand White (NZW) rabbits was 0.0112 -/+ 0.0016 (SD) pg per ng tissue RNA. TNF-alpha mRNA levels in the aortic arches and descending thoracic aortas of 6-month-old WHHL rabbits were 0.0273 -/+ 0.0066 pg and 0.0176 -/+ 0.0013 pg per ng tissue RNA, respectively. TNF-alpha mRNA levels in the aortic arches and descending thoracic aortas of 18-month-old WHHL rabbits were much higher than in those of 6-month-old WHHL rabbits, with values of 0.2107 -/+ 0.0205 pg and 0.1043 -/+ 0.0196 pg per ng tissue RNA, respectively. These findings indicate that: a) Quantitative RT-PCR can be used to measure levels of small abundance RNA in normal and diseased tissues accurately; b) no significant increase in TNF-alpha mRNA levels was observed in the aortic arches and descending thoracic aortas of 6-month-old WHHL rabbits compared with those of NZW rabbits, although they had multiple raised intimal lesions; and c) a significantly elevated total tissue level of TNF-alpha mRNA is demonstrable late in the course of atherosclerosis in 18-month-old WHHL rabbits (Bonferroni method). These findings suggest that TNF-alpha might play an important role in the progression of advanced atherosclerosis, although total tissue levels of TNF-alpha mRNA are not unequivocally elevated earlier in the course of the disease.

Animals↗
PubMed1996

[Diagnostic value of color Doppler flow imaging in gestational trophoblastic diseases].

OBJECTIVE: To investigate the value of color doppler flow imaging (CDFI) and pulsed doppler (PD) determinations in early diagnosis, evaluation of therapeutic effects and prediction of prognosis of gestational trophoblastic diseases (GTD). METHOD: CDFI and PD were performed in 55 cases of GTD and 30 normal pregnant women as controls. RESULTS: The uterine muscular layer in GTD showed multicolored abundant blood flow and blood sinuses. Blood flow resistance was low with a resistance index (RI) less than 0.5. After chemotherapy the RI changed dramatically. Pathological evidences were found in surgical specimens of 8 patients. Findings of pelvic hysterography in 16 cases were in accordance with the results of CDFI and PD determinations. CONCLUSION: CDFI and PD as new methods for early diagnosis of GTD can also be used to evaluate the chemotherapeutic results as well as to determine the prognosis of the disease.

Adult↗
PubMed1996

[Effects of AT-I on murine cytokins productions and NK cell activity in vivo].

Antitumor-I (AT-I) is a traditional Chinese medicine, which known to be combined with chemotherapeutic agent on antitumor effects. In this paper, the effections of AT-I on interleukin-2 (IL-2) and interleukin-6 (IL-6) was detected and NK cell activity were observed in normal and tumor-bearing BALB/c mice in vivo. The results showed that AT-I could enhance IL-2 and IL-6 production in normal mice, and IL-2 product in tumor-bearing mice. The results suggest that AT-I at a appropriate dose could modulate immunofunctions, so known as a biological response modifier (BRM).

Animals↗
PubMed1996

[Effects of AEA-I on murine IL-2 and IL-6 activities in vivo].

Antitumor-I (AT-I) is known as an effective traditional Chinese medicine to be used in combination with chemotherapeutic agents against tumor. It was demonstrated that AT-I could inhibit tumor growth and modulate IL-2, IL-6 and NK cell activities. In order to improve its preparation, we got the alcohol extract from AT-I (AEA-I) by using natural pharmaceutical alcohol extract method, and compared the effect of AEA-I on cytokins with that of AT-I. The results show that AEA-I has a good positive correlation with AT-I on IL-2 and IL-6 activities of mice in vivo.

Animals↗
PubMed1995

[Radiologic study of ossifying fibroma of the facial and jaw bones].

83 cases with ossifying fibroma were diagnosed by clinical, histopathological and radiological criteria, and were analyzed radiologically. Four distinct radiographic patterns were identified according to the radiodensity and shape: (1) cystic radiolucent (42.2%), (2) ground-grass (7.2%), (3) sclerotic change (9.6%), (4) mixed change of radiolucent and radiopaque (41.0%). The lesions showed a growth pattern of round expanding in all directions with well-defined margin and frequent involvement of teeth. A preliminary analysis of the relationship among the clinical, radiological and histopathological manifestations was presented. The diagnostic criteria was proposed and differentiate diagnosis was discussed.

Adolescent↗
PubMed1994

Molecular maturation of cell adhesion systems during mouse early development.

During cleavage, the mouse embryo expresses a variety of cell adhesion systems on its cell surfaces. We have reviewed biogenetic and assembly criteria for the formation of the uvomorulin/catenin, tight junction and desmosome adhesion systems as the trophectoderm differentiates. Each system reveals different mechanisms regulating molecular maturation. Adhesion processes contribute to the generation of distinct tissues in the blastocyst by modifying the expression pattern of blastomeres entering the non-epithelial inner cell mass lineage. Cell adhesion also influences the spatial organisation, but rarely the timing of expression, of proteins involved in trophectoderm differentiation.

Animals↗