Biomedical subjects

F Chen

Publications and source records attributed to F Chen.

At least 307 records · Page 17Linked to original sources

PubMed1999

[Expression of WT1 gene mRNA in leukemia].

UNLABELLED: WT1 gene expression was determined in acute leukemic patients by RT-PCR. RESULTS: 19 patients were found to have positive results among 28 patients, the positive rate is 67.9%, and in 16 ANLL patients, 11 cases got positive results, in 12 ALL patients, 8 cases got positive results. It suggested that WT1 was highly expressed in acute leukemia. It is a new and significant detective marker for monitoring the effect of chemotherapy, predicting the prognosis and in the research of minimal residual disease (MRD).

Acute Disease↗

PubMed1999

[Cartilage matrix synthetic ability of rabbit articular chondrocytes cultured in vitro].

OBJECTIVE: To observe the ability of matrix synthesis of rabbit articular chondrocytes cultured in vitro. METHODS: Rabbit articular chondrocytes were acquired by digestion of 0.1% type II collagenase and cultured in vitro, then cell morphology and ultrastructure were observed with phase-contrast microscope and scanning electronic microscope. With continuous culturing of chondrocytes in DMEM medium containing 15% FBS, synthesis of cartilage matrix was observed by using microscope and safranine-O staining. RESULTS: The cultured chondrocytes were polygonal cells. There were many rough endoplasmic reticula and mitochondria in cytoplasm, and a lot of secretory vesicles under cell membrane and in the cytoplasm. When cultured for 10 days, some small and white nodules were formed on the bottom of the culture dishes, and volcanic-mouth-like structures were formed when cultured for 20 days. Both these nodules and structures contained GAG-positive substances were demonstrated by safranine-O staining. CONCLUSION: Chondrocytes can produce matrix and cartilage-like tissue in vitro, so it is feasible to produce cartilage by culturing chondrocytes in vitro.

Animals↗

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

[The simultaneous determination of permethrin and tetramethrin in their mixed mothproofer formulation by GC].

Mixed mothproofer of permethrin and tetramethrin is a new formulation for prevention cloth moth in China. A rapid and specific method is needed to simultaneously determine these two active ingredients. For this purpose, a method by GC was established with a 3% OV-101/Chromosorb WAW DMCS(180-250 microns) column at a temperature of 223 degrees C, by using di-iso-octylsebacate as internal standard. The mean coefficient of variation for permethrin and tetramethrin were 0.20% and 0.19% respectively. Linearity of detector response vs. mass concentration ranged from 0.38-2.6 g/L with r = 0.9999.

English Abstract↗

PubMed1999

[Investigating the phenomenon of total erythrocyte destruction during an in-vitro hemolysis test by roller pump].

This study sought to address the question, "will the phenomenon of 'total erythrocyte destruction' come about during a long time of in vitro hemolysis test by roller pump". One-day-old boving blood was employed in the test by Polystan pump(group A) and Cobe pump (group B). TMB method was used to measure the level of plasma-free hemoglobin. The samples of plasma-free hemoglobin were taken at the time before pumping and pumping for 4,6,8,10, 12,14 and 16 hours. The index of hemolysis was calculated according to Koller's formula. The results showed that the levels of plasma-free hemoglobin in the two groups both increased linearly during the puming of blood. The index of hemolysis was 0.2960 mg/L group A, and 0.3993 mg/L in group B; no statistically significant difference was noted between the two groups. These data indicated that no phenomenon of "total erythrocyte destruction" was observed in this hemolysis test by roller pump.

Erythrocytes↗

PubMed1999

[Study on the analytical method of methyl-parathion and phoxim in methyl-parathion, phoxim and cypermethrin mixed formulation].

This paper describes an HPLC method to simultaneously determine methyl-parathion and phoxim in mixed formulation of methyl-parathion, phoxim and cypermethrin. A C8 column was used. The mobile phase was V(MeOH):V(H2O) = 70:30, Methyl-parathion and phoxim were monitored at 254 nm or 280 nm by UV detector. The average recoveries were 99.8% and 99.9% for methyl-parathion and phoxim respectively. The linearity of detector response vs concentration was calibrated in the concentration ranges from 0.1746 to 1.091 g/L for methyl-parathion and from 0.1927 to 1.205 g/L for phoxim.

English Abstract↗

PubMed1999

[Analysis of mathematical model parameters for continuous rotary annular chromatography].

The curves of analysis solution of mathematical model for continuous rotary annular chromatography (CAC) coincide with experimental results well, but some points are derived from theoretical values due to the errors from experimental method. The width and the angles of maximum mass concentration solution at outlet (retention number), except for the other experimental conditions, depend on phase equilibrium coefficient and transfer functions. Because the precision of model parameters is strongly affected by the correction of experimental method, the sensitivities of phase equilibrium coefficients and transfer functions have been studied, in which the phase equilibrium coefficient is the key parameters to improve the separation effect of CAC process.

Biotechnology↗

PubMed1999

[Changes in transforming growth factor beta 1 mRNA and its clinical value in patients with schistosomal liver fibrosis].

AIM: To explore the changes in TGF-beta 1 mRNA in patients with schistosomal liver fibrosis. METHODS: Reverse-transcription polymerase chain reaction and dot blot analysis were used to determine the level of TGF-beta 1 mRNA in PBMC. The serum levels of hyaluronic acid, type IV collagen, laminine and procollagen III peptide were also measured simultaneously. RESULTS: The mean level (m +/- s) of PBMC TGF-beta 1 mRNA was significantly higher in late-stage schistosomiasis group (LSS) (1.26 +/- 0.14), liver cirrhosis group (LC) (2.05 +/- 0.81) and hepatocellular carcinoma group (HCC) than that in control group (0.62 +/- 0.40) (P < 0.05). PBMC TGF-beta 1 mRNA level was higher in LC and HCC than that in LSS (P < 0.05). No significant difference was found in TGF-beta 1 mRNA between PBMC and liver tissue in patients with HCC. All patients with increased fibrogenic activity (i.e., abnormal levels of serum HA, Col-IV and LN) had increased levels of TGF-beta 1 mRNA. CONCLUSION: The level of TGF-beta 1 mRNA is correlated with the fibrotic activity of liver, the increasement of TGF-beta 1 mRNA in schistosomiasis patients after praziquantel treatment might induce liver fibrosis.

Adult↗

PubMed1999

[The influences of vowel ae and a: on acoustic measures].

OBJECTIVE: To study the influences of vowel ae and a: on acoustics measures. METHOD: Fifty-three cases of laryngeal diseases were measured acoustically. The acoustic sampling were vowels ae and a:. RESULT: The results showed that Fo, Jitter and Shimmer were similar between two groups, and NNE of vowel a: was much lower than that of ae, indicating larger glottal closure in vowel a:. CONCLUSION: Vowels have something to do with glottal closure, therefore influencs acoustical measures.

Acoustics↗

PubMed1999

[Quantitative analysis of vocal fold vibration].

OBJECTIVE: To measure vocal fold vibration quantitatively and study the effects of gender and phonation mode. METHOD: The authors adopted a new computerized image analysis technique and EGG in 60 normal speakers, and the parameters of vocal fold vibration were measured and analyzed according to the loudness, pitch and gender. RESULT: With frequency increasing, CQ got smaller and OQ larger which expressed longer open phase. As intensity increased, the duration of open phase became shorter and the closing phase got relatively much shorter. Males had a longer closed phase than females. The closing duration appeared relatively shorter than opening duration in phonation. CONCLUSION: The quantitative measures of vocal fold vibration become feasible with modern computers and commercially available image analysis software. Certain features of vocal fold vibration vary with intensity variations, while others vary with gender or frequency variation.

Adolescent↗

PubMed1999

[GC-MS analysis of essential oil from the leaves of Psidium guajava].

The constituents of essential oils from the leaves of Psidium guajava Linn were analyzed by GC-MS qualitatively and quantitatively. Sixty compounds of the essential oils were identified at rate 90.56%. The major components were caryophyllene (18.81%), copaene (11.80%), [1aR-(1a alpha, 4a alpha, 7 alpha, 7a beta, 7b alpha)]-decahydro-1,1,7-trimethyl-4-methylene-1H-cycloprop[e] azulene(10.27%), eucalyptol(7.36%).

Cyclohexanols↗

PubMed1999

[Cuttage of Santalum album].

The effects of cuttage times, miaternal plant ages, hormones and mediums on the taking root of a cutting were studied in 1991-1996. The results showed that the sprouts of germinating and growing 20-30 days from the cut back of maternal plant as cuttings, the rate of the taking root get to about 70%; the suitable cuttage time was in June to August; the proper medium was river sands, but the effects of hormones were not obvious.

Gardening↗

PubMed1999

Comparison of bone mass in forearm, lumbar vertebra and hip by single and/or dual energy X-ray absorptiometry.

OBJECTIVE: Bone mineral density (BMD) was measured in normal Chinese women with single X-ray absorptiometry (SXA) and dual energy X-ray absorptiometry (DEXA). These two methods were compared to evaluate the sensitivity in reflecting bone loss. METHODS: Measurements were performed in 300 women aged 20 to approximately 79 (5 for each age). The 8mm distal, 1/4 distal, ultra distal site of the nondominant forearm were measured with SXA; the AP spine (L2-4), right femoral neck (Neck), Ward's triangle (Ward) and trochantor (Troch) were measured with DEXA. Ten women had 5 repeated measurements to evaluate the reproducibility of the equipments. RESULTS: The BMD peak for Neck and Ward was found between age 20 to approximately 29, for ultra distal and L2-4 at age 30 to approximately 39, for 8mm distal, 1/4 distal and Troch at age 40 to approximately 49. After reaching the peak values, BMD at all sites decreased with increasing age. The highest rate of yearly loss of BMD was at 8mm distal. Results of measurement showed significant correlation between SXA and DEXA. Comparing with premenopausal women, the bone loss rate in postmenopausal women was faster and highest up to 11 to approximately 15 years and the highest rate was at the Ward. CONCLUSION: The present study gives the normal values of BMD at seven sites for normal Chinese women. The ages of BMD peak were different at seven sites. The yearly loss of BMD was highest at 8mm distal, it seemed to be the sensitive region for bone loss with age. The postmenopausal women had highly significantly loss bone mass than the premenopausal women. Comparing with premenopause, postmenopause BMD for Ward's triangle with DEXA seemed to be most sensitive to the effect of menopause.

Absorptiometry, Photon↗

PubMed1999

New insights into the role of nuclear factor-kappaB, a ubiquitous transcription factor in the initiation of diseases.

Nuclear factor-kappaB (NF-kappaB) is a ubiquitous transcription factor that governs the expression of genes encoding cytokines, chemokines, growth factors, cell adhesion molecules, and some acute phase proteins in health and in various disease states. NF-kappaB is activated by several agents, including cytokines, oxidant free radicals, inhaled particles, ultraviolet irradiation, and bacterial or viral products. Inappropriate activation of NF-kappaB has been linked to inflammatory events associated with autoimmune arthritis, asthma, septic shock, lung fibrosis, glomerulonephritis, atherosclerosis, and AIDS. In contrast, complete and persistent inhibition of NF-kappaB has been linked directly to apoptosis, inappropriate immune cell development, and delayed cell growth. Therefore, development of modulatory strategies targeting this transcription factor may provide a novel therapeutic tool for the treatment or prevention of various diseases.

Animals↗

PubMed1998

The role of host (endogenous) T cells in chronic graft-versus-host autoimmune disease.

Chronic graft-vs-host (cGVH) disease induced by the transfer of Ia-incompatible spleen cells from one normal mouse strain (such as B6.C-H2(bm12)/KhEg (bm12)) to another (such as C57BL/6) causes an autoimmune syndrome resembling systemic lupus erythematosus (SLE). The role of host-derived T cells in this response is not obvious. Previous reports suggested that host T cells might serve to down-regulate the autoimmune syndrome. To address this issue more definitively, we used CD4 knockout (KO) or CD8KO C57BL/6 (B6) mice as recipients in the bm12-->C57B6 cGVH model. CD4KO B6 mice injected with allogeneic bm12 spleen cells (bm12-->CD4KO group) showed no evidence of cGVH disease. They made no detectable autoantibodies, including anti-chromatin, anti-dsDNA, anti-ssDNA, and rheumatoid factor. They survived at least 20 wks after induction of cGVH disease; and they did not develop nephritis, based on the absence of detectable levels of proteinuria and normal renal histology at the time of sacrifice. By contrast, CD8KO B6 mice (bm12-->CD8KO group) and normal B6 mice (bm12-->B6 group) injected with bm12 spleen cells generally showed similar levels of mortality, nephritis, and autoantibodies, although the autoantibody titers declined somewhat after week 8 in the bm12-->CD8KO group. Control groups of recipients injected with B6 spleen cells showed no induction of autoantibodies. A surprising finding, however, was that the B6-->CD8KO group developed severe histologic glomerulonephritis in the absence of autoantibodies and with decreased immune deposits. These results indicate that endogenous (host) CD4+ T cells play an essential role in the cGVH autoimmune syndrome.

Animals↗

PubMed1998

The relationship between biological activity and the electronic structure and transfer of the whole acidic PLA2 molecule in ab initio level.

The electronic structure of the whole molecule of acidic phospholipase A2 (PLA2) from the venom of Agkistrodon halys pallas (A. halys pallas) has been calculated using the extended negative factor counting (ENFC) method in which dimers were calculated at the ab initio level using a minimal basis set, with simulation of the aqueous environment. Hopping conductivities were determined by the use of random walk theory. The results show that the frontier orbitals are mainly localized to residues which are involved in the biological activity of acidic PLA2. The C-terminal region might play some important role in biological activity because of its active electrons. The aromatic patch on the surface of the enzyme, together with two neighbouring acidic residues, has very active electrons that may be responsible for the inhibition of platelet aggregation. Trp30, which is involved in the interfacial recognition region, may transfer its electrons to the aggregated substrate. It is also concluded that the conductivity of the protein is caused mainly by holes transported through the valence band rather than electrons transferred in the conductive band. The a.c. conductivity of acidic PLA2 confirms that proteins, if doped, are amorphous conductors. Moreover, the a.c. conductivities of acidic PLA2 are approximately one order of magnitude higher than those of some other proteins. This suggests that the toxicity of acidic PLA2 may be related to its high a.c. conductivity.

Agkistrodon↗

PubMed1998

[Relationship between methylenetetrahydrofolate reductase gene polymorphism and coronary heart disease].

OBJECTIVE: This study inquired into the relationship between methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and coronary heart disease. METHODS: By polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP), MTHFR 677C-->T mutation was detected in 79 healthy controls and 69 patients with coronary heart disease. RESULTS: The frequency of MTHFR variant V677 of patients was significantly higher than that of healthy controls (P<0.01). CONCLUSION: This study demonstrated that MTHFR gene V677 mutation was probably one of the genetic risk factors of coronary heart disease and this provided a new basis for exploring the relevant pathogenesis.

Coronary Disease↗

PubMed1998

Infection of human fetal cardiac myocytes by a human immunodeficiency virus-1-derived vector.

Cardiomyopathy associated with HIV-1 infection is a well-recognized complication. However, it is unknown whether direct cardiomyocyte infection is involved in the pathogenesis of the cardiomyopathy. An HIV-1-based lentiviral vector and wild-type HIV-1 were used to infect human fetal cardiac myocytes in a primary culture. Quantitative polymerase chain reaction, viral p24 antigen determination, and immunofluorescence were used to detect the synthesis of HIV-1 DNA and proteins after the infection. High-efficiency infection occurred using the HIV-1-based lentiviral vector, although no infection occurred with the wild-type HIV-1 strain. Dual-labeling immunofluorescence for HIV-1 proteins and myosin confirmed that cardiomyocytes were infected. This in vitro analysis suggests that direct myocyte infection with wild-type HIV-1 may not be involved in the pathogenesis of HIV-1 cardiomyopathy. However, HIV-1-based vectors may prove useful for ex vivo cardiovascular gene therapy.

Acquired Immunodeficiency Syndrome↗