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Biomedical subjects

Y Chen

Publications and source records attributed to Y Chen.

At least 1,225 records · Page 68Linked to original sources
PubMed1999

[Development of a multi-channel physiological telemetry system].

OBJECTIVE: To develop an instrument used in measurement of physiological parameters in laboratories or field. Method A: computer was used to process data in the telemetry system. The frequency-time division modulation technique was adopted. The low frequency signals were directly connected to the computer serial port after demodulation, and measurement control was achieved by single-chip computer. Temperature measurement results were obtained by conversion table. RESULT: It is capable of telemeter and processing ECG, wind speed and temperature signals in real-time. Good results were gained in high temperature condition and -17 degrees C environment. CONCLUSION: The instrument has many advantages, such as high accuracy, good processing ability, reliability, long operation distance, small volume and easy operation.

Aerospace Medicine↗
PubMed1999

Importance of somatosensory input for spatial orientation in supine subjects: evaluated by pointing arm movements during linear acceleration.

Goal-directed movements are secured by sensory interactions among visual, vestibular and somatosensory information. Reliable inputs from the visual system have been known, and the contribution of otolithic information demonstrated most clearly by evidence that target-pointing arm movements shifted downward in astronauts with eyes closed under space microgravity (Watt 1997), whereas the direction of shift was the opposite in subjects under centrifuge hypergravity (Bock et al. 1996). Somatosensory contribution has been also supported by many reports. In the present study, we attempted to evaluate the otolithic contribution to spatial orientation by arm-pointing deviation in supine subjects exposed to Z-axis linear acceleration in darkness.

Acceleration↗
PubMed1999

Reversal of aberrant splicing of beta-thalassemia allele by antisense RNA in vitro and in vivo.

OBJECTIVE: To investigate the reversal of aberrant splicing of beta-thalassemia allele (IVS-2-654 C-->T, beta 654) by antisense RNA in vitro and in vivo. METHODS: The vector expressing antisense RNA which targeted against the aberrant splice sites of beta 654 pre-mRNA was constructed in pcDNA3, and then used to repair the defective splicing of the mutant pre-mRNA in an in vitro transcription and splicing system, as well as in HeLa beta 654 cells and cultured beta 654 erythroid cells by lipid-mediated DNA-transfection method. The effect of the antisense RNA was identified by RT-PCR mediated mRNA quantitative assay as well as globin chain microbiosynthesis. RESULTS: The antisense RNA decreased the aberrant splicing product and restored the correct splicing pattern in vitro and in vivo efficiently. In the in vitro transcription and splicing system, the level of normally spliced mRNA [beta/(beta + beta*)] increased from 0.25 to 0.60. In cultured HeLa beta 654 cells, the level of beta/(beta + beta*) increased from 0.07 to 0.43 on the 15th day after transfection. In cultured beta 654 erythroid cells, the level of mRNA [beta/(beta + beta*)] increased from 0.19 to 0.58 on the 8th day after transfection in beta 654/beta 654 erythroid cells, from 0.02 to 0.38 in beta 654/beta 41-42 erythroid cells, and from 0.45 to 0.83 in beta 654/beta A erythroid cells, respectively. Correspondingly, the ratios of globin chain (beta/alpha) biosynthesis increased from 0.16 to 0.52 on the 8th day after transfection in beta 654/beta 654 erythroid cells, 0.05 to 0.36 in beta 654/beta 41-42 erythroid cells, and 0.42 to 0.81 in beta 654/beta A erythroid cells, respectively. The splicing pattern did not show significant changes as compared to the untreated, as well as to the control antisense fragment. CONCLUSIONS: Antisense RNA transcribed from the expression vector described here could efficiently suppress the aberrant splicing pattern of beta 654 mutant mRNA and restore the correct splicing pathway in vitro and in vivo, leading to the improvement of globin chain biosynthesis in thalassemic cells. Our antisense strategy provides an alternative approach to the gene therapy of beta-thalassemia.

Adolescent↗
PubMed1999

[Inhibition of mesangial cell proliferation and mesangial matrix expansion by antisense oligodeoxynucleotide targeting preproendothelin-1 mRNA in vivo].

OBJECTIVE: To investigate the effect of endothelin-1 (ET-1) on mesangial cells(MC) proliferation and mesangial matrix expansion in vivo. METHODS: Antisense oligodeoxynucleotide(As-ODN) and its control sequences, sense oligodeoxynucleotide(Se-ODN) and mismatch oligodeoxynucleotide(Mis-ODN), targeting pre-proendothelin-1 mRNA (ppET-1) were delivered into the kidney of rats with mesangioproliferative glomerulonephritis (MsPGN) model respectively at day 2 by lipofectin-mediated gene transfer method. The efficiency of transfer of ODNs into MC was examined with biotinylated As-ODN staining. Four days after the rats were sacrificed, the influence of ODNs on ET-1 production by glomeruli was tested with radioimmunoassay(RIA). The action of ODNs on MC proliferation and mesangial matrix expansion was evaluated with quantitative pathologic analysis. RESULTS: ODNs were transferred into MC in vivo. The glomerular ET-1 production was decreased by As-ODN [(32 +/- 19) ng/g, P < 0.05] with reduction of mesangial cell proliferation [(0.82 +/- 0.04)/100 micron 2, P < 0.05] and mesangial matrix expansion[(12.8 +/- 1.6)%, P < 0.05], where Se-ODN and Mis-ODN did not show any effect on all of these. CONCLUSIONS: Specific inhibition of ET-1 gene expression leads to reduction of proliferation of mesangial cell and expansion of mesangial matrix in rats with MsPGN model. ET-1 is one of the important inflammatory mediators which can stimulate MC proliferation and mesangial matrix expansion in vivo.

Animals↗
PubMed1999

[Clinical and experimental study of 9 cases of adult T cell leukemia].

OBJECTIVE: In order to clarify the clinical and laboratory features of adult T cell leukemia (ATL): morphology, immunology, cytogenetics, serology and molecular biology. METHODS: Indirect immunofluorescence assay and ELISA were used to detect serum HTLV-I antibody. The HTLV-I provirus sequence were amplified by PCR and confirmed by liquid hybridization. RESULTS AND CONCLUSION: Nine cases of ATL were diagnosed. The major clinical manifestation was lymph node enlargement found in all patients. Skin involvement and osteolysis were not frequent. The characteristic finding was leukemic cells with highly indented or lobulated flower-like nuclei in peripheral blood and bone marrow. ATL cells were CD2, CD3, CD4, CD25 positive and CD8 negative. No specific chromosome abnormality or HLA type was found. Seven of 8 patients examined had HTLV-I antibody. The HTLV-I provirus genome sequence integrated into host cell DNA was amplified by PCR and confirmed by liquid hybridization. All of these results showed that HTLV-I was also the etiological agent of ATL in China. One of the 9 cases of ATL was classified as lymphoma type, one as chronic-type, and the rest as acute type.

Adult↗
PubMed1999

[Experimental study of cord blood plasma enhancing the anti-leukemia effect of Ara-C].

OBJECTIVE: To study the in vitro effect of cord blood plasma(CBP) on the sensitivity of acute myeloid leukemia(AML) cells to cytosine arabinoside (Ara-C). METHODS: Cytotoxicity of Ara-C was detected by MTT assay in twenty-eight patients. RESULTS AND CONCLUSION: The sensitivity of AML cells to Ara-C was heterogeneous, but CBP could significantly enhanced the cytotoxic activity of Ara-C to drug resistant AML cells.

Adolescent↗
PubMed1999

[Study on the pathogenesis of acquired pure amegakaryocytic thrombocytopenic purpura].

OBJECTIVE: To investigate the possible pathogenesis of acquired pure amegakaryocytic thrombocytopenic purpura(APATP). METHODS: Twenty eight patients with APATP were studied. Bone marrow mononuclear cells(MNCs) from these patients were plated into methyl cellulose cultures for CFU-GM, CFU-E and CFU-MK assay. The influence of depleting T cells or adherent cells from patients' marrow cells on CFU-MK growth was observed. The humoral inhibitory effect on CFU-MK was determined by co-incubation of patients' sera or IgG with normal or autologous MNCs prior to cultures. The serum MK-CSA was also assessed. RESULTS: Fifteen cases (53.6%) of APATP was resulted from intrinsic defect of CFU-MK. The megakaryocyte colony formation was augmented significantly in 3 T lymphocytes-depleted and 2 mono-macrophages depleted patients. Sera from 6 patients(21.4%) were inhibitor to CFU-MK. The inhibitor originated from IgG and selectively directed against the megakaryocyte. In the remaining 2 cases, the pathogenesis was not ascertained. CONCLUSION: The intrinsic defect of megakaryocyte progenitor cell is considered to be a primary pathogenesis of APATP. In some patients the disease can result from abnormal immune mechanisms. The decompensation of MK-CSA production could also be an important cause for APATP.

Adolescent↗
PubMed1999

A surveillance study on penicillin-resistant streptococcus pneumoniae in China.

OBJECTIVES: To find out whether there are also penicillin-resistant streptococcus pneumoniae and the resistant rate in China. METHODS: A surveillance study which is a part of the international surveillance on pneumococci resistance to penicillin and other antimicrobial agents was conducted in Beijing, China. More than 900 pediatric patients with respiratory tract infections aged from six months to three years selected from two pediatric units were enrolled in the study. Perthroat swabs were immediately streaked onto blood agar plates. Isolates were identified as pneumococci by their typical appearance, gram stain, confirmation tests. Antibiotic susceptibility was assessed by the disk diffusion method and minimal inhibition concentration (MIC) determination according to Protocol and National Committee for Clinical Laboratory Standards (NCCLS). RESULTS: Of the 51 streptococcus pneumoniae isolates, 5 strains had zones of inhibition indicative of penicillin resistance, of which two had penicillin MICs > or = 0.1 mg/L and were considered to be relatively or fully resistant to penicillin. The MICs of two penicillin resistant strains were 2 mg/L and 4 mg/L. Resistant rates to ceftriaxone and cefotaxime were 0% and 10% respectively. For the other ten antimicrobial agents, the resistant rates were as follows: ampicillin 12%, piperacillin 26%, furbenicillin 14%, cefuroxime 6%, erythromycin 54%, clarithromycin 52%, meleumycin 64%, roxithromycin 52%, chloramphenicol 35%, tetracycline 100%. CONCLUSIONS: The study suggested that penicillin resistant streptococcus pneumoniae strains existed in China and were also resistant to ampicillin, piperacillin, furbenicillin and cefuroxime. Moreover, the resistant rates of penicillin resistant streptococcus pneumoniae to macrolides and tetracycline were high.

Ampicillin Resistance↗
PubMed1999

[cDNA cloning of a novel gene related to apoptosis by differential display RT-PCR].

OBJECTIVE: To search for the novel gene related to apoptosis. METHODS: The mRNA expression patterns of U937 cells treated with or without trichosanthin were compared with differential display RT-PCR. The cDNA, which was highly expressed in the apoptosis cells, was used as a probe to screen the human fetal liver cDNA library. RESULTS: A 1.4 kb cDNA segment was the partial sequence of a novel gene related to apoptosis. The result of Northern blot showed three bands in the apoptosis cells. Some sequence of the 1.4 kb cDNA was homology to Bruton's tyrosine kinase. CONCLUSION: A partial cDNA of a new gene related to apoptosis was found.

Apoptosis↗
PubMed1999

Inhibition of mesangial cell proliferation by antisense oligodeoxynucleotide targeting preproendothelin-1 mRNA in vitro.

OBJECTIVE: To investigate the effects of endothelin-1 (ET-1) on mesangial cell proliferation in vitro. METHODS: Antisense oligodeoxynucleotide (As-ODN) and its control sequences, sense (Se-ODN) and mismatch (Mis-ODN) oligodeoxynucleotides, targeting preproendothelin-1 (ppET-1) mRNA were delivered into cultured human mesangial cells (HMC) with lipofectin-mediated gene transfer method. The cytotoxicity of lipofectin was determined with lactate dehydrogenase (LDH) release assay. The efficiency of ODNs transfer into HMC was examined with biotinylated As-ODN staining. The effect of As-ODN on expression of ppET-1 mRNA was analyzed with semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The action of As-ODN on HMC ET-1 secretion was tested by radioimmunoassay (RIA). The influence of As-ODN on HMC proliferation was evaluated with MTT method. RESULTS: As-ODN was transferred into HMC with lipofectin without any impairment of cell viability. The ppET-1 mRNA expression, the ET-1 secretion and the cell proliferation were inhibited by As-ODN transferred into HMC, while Se-ODN and Mis-ODN transferred into HMC did not show any effects on all of these. CONCLUSION: Decrease of ET-1 secretion by HMC, caused by the down-regulation of ppET-1 mRNA expression after As-ODN transfer, led to inhibition of HMC proliferation. These results suggest ET-1 is one of the autocrine growth factors of HMC, and may play an important role in the pathogenesis of proliferative glomerulonephritis.

Cell Division↗
PubMed1999

Interaction between gene p53 and oncogene mdm2 in human glandular lung cancer cell line GLC-82.

OBJECTIVE: To study the interaction between oncogene mdm2 and wp53 in human glandular lung cancer cell line GLC-82. METHODS: By lipofectamine-mediated DNA transfection, wp53 and mdm2 were transfected separately or co-transfected into GLC-82 cells via retrovival vector pDOR-neo, a carrier of wp53 and mdm2. RESULTS: The growth of GLC-82 cells was blocked and their DNA synthesis inhibited by wp53, its colony-forming rate in soft agar culture and the tumorigenicity in nude mice declined and mdm2 antagonized the function of wp53. CONCLUSION: After the recombinant vector pDOR-mdm2 was transfected into GLC-82 cells containing wp53, mdm2 partially deprives wp53 of its function of inhibiting the growth of GLC-82 cells.

Adenocarcinoma↗
PubMed1999

[Design and synthesis of anti-PML-RAR alpha antisense and its effects on the growth and apoptosis of NB4 cells].

OBJECTIVE: To synthesize antisense oligodeoxynucleotides (AS) targeting the fusion point region (FUAS) and the start codon region (STAS) of the long type PML-RAR alpha mRNA and investigate its stability, specificity and effects on the growth and apoptosis of NB4 cells. METHODS: NB4 cell apoptosis was assayed by flow cytometry, cell-fluorescence and DNA gel electrophoresis. Trypan blue exclusion was used for cell counts, and polyacrylamide gel electrophoresis for oligodeoxynucleotides. RESULTS: The synthesized 18 bp phosphorothioate oligodeoxynucleotides was stable, resistant to nuclease, and no unspecific effects. Both STAS and FUAS could inhibit the NB4 cell growth in a dose-dependent manner. Low concentration (20 micrograms/ml) of STAS or FUAS resulted in growth inhibition of 0%-11.3%, and the highest inhibition was found at concentration of 80 micrograms/ml (inhibition rate 50.0%-67.7%). Cell DNA content analyzed by flow cytometry showed the typical profile of apoptotic cells at 7th day, 9th day of treatment with FUAS. Percentages of apoptotic cells in FUAS-treated cells was 9.3%, 24.5%, 41.0% and 34.2% after 3, 5, 7 and 9 days of FUAS treatment, respectively. CONCLUSION: STAS and FUAS successfully synthesized and both of them could inhibit the growth and induce the cell apoptosis of NB4 cells.

Apoptosis↗
PubMed1999

[Effects of anti-PML-RAR alpha antisense on cell morphology and expression of PML-RAR alpha mRNA and protein of NB4 cells].

OBJECTIVE: To investigate the effects of anti-PML-RAR alpha antisense (FUAS) on cell morphology, expression of PML-RAR alpha mRNA and PML-RAR alpha/PML protein localization of NB4 cells. METHODS: PML-RAR alpha mRNA expression was assayed by RT-PCR and PML-RAR alpha/PML protein localization by immuno-fluorescence. RESULTS: NB4 cells were partially differentiated after 5 days of FUAS treatment and typical apoptosis was found after 7 days incubation with FUAS. The expression of PML-RAR alpha mRNA at 24 h was already down regulated in FUAS-treated cells. After 24 h, 72 h and 120 h incubation with FUAS, PML-RAR alpha mRNA showed 52.0%, 68.7% and 23.4% reductions, respectively, as compared with that of control. Immuno-fluorescence analysis with anti-PML monoclonal antibody showed disappearance of microgranules, residual granules becoming larger discrete dots at 24 h of FUAS treatment and almost disappearence of dots at 120 h. CONCLUSION: FUAS specifically blocks the expression and translation of PML-RAR alpha gene, makes the production of PML-RAR alpha fusion protein decrease or disappear and prompts cell differentiation.

Cell Division↗
PubMed1999

Partial left ventriculectomy for the treatment of end-stage dilated cardiomyopathy.

OBJECTIVE: To report our initial experience of the first 5 cases of partial left ventriculectomy (PLV or Batista operation), a new surgical therapy for treatment of end-stage dilated cardiomyopathy in China. METHODS: From April to August 1998, 5 patients with idiopathic dilated cardiomyopathy received PLV at Anzhen Hospital. The mean age of the patients was 48.4 years (range: 42 to 53 years). Three patients were in New York Heart Association (NYHA) class III and 2 in class IV. All patients had mitral valve insufficiency (3 moderate and 2 severe) and 1 had severe tricuspid valve insufficiency in addition preoperatively. Cardiopulmonary bypass and cardiac arrest with cold blood cardioplegia were used in all patients. The average weight of the resected left ventricle muscle was 46.3 g. All patients underwent mitral annuloplasty and 1 plus tricuspid annuloplasty (De Vega). RESULTS: Echocardiography demonstrated a significant decrease in left ventricular diastolic diameter (8.4 +/- 1.1 cm to 5.4 +/- 0.4 cm, P < 0.01) and an increase in ejection fraction (17.78% +/- 6.26% to 34.82% +/- 3.18%, P < 0.025). One patient died of heart failure on the 6th postoperative day. The mean follow-up period of the 4 discharged patients were 4 months (from 3 to 6 months). One were in NYHA class I and 3 in class II; all had a normal life. CONCLUSION: Batista operation is a new and valuable alternative of the surgical treatment for end-stage dilated cardiomyopathy and the long-term results need further studies.

Adult↗
PubMed1999

[Combined endobronchial and percutaneous radiotherapy after implanting the nitinol alloy endotrachial stent for advanced lung carcinoma].

OBJECTIVE: For the purpose to observe the effectiveness of treatment in late stage patients with bronchogenic carcinoma by implanting nitinol alloy endotrachial stent, combined with endobronchial 192 iridium (Ir) and percutaneous radiotherapy. METHODS: The nitiol alloy endotrachial stent was put into the site of airway stenosis through a special introducer under direct optical fibrobronchoscopy without the help of X-ray examination nor guided steel-line. 192 Ir was inserted to the site of tumor via bronchofiberscope for endobronchial irradiation combining with percutaneous radiotherapy alternately. RESULTS: In all 20 patients, 7 cases (35%) were completely cured and 11 cases (55%) showed partial recovery. The other 2 cases, no change or deteriorated. The 90% effective rate was significantly higher than 60% of control group (P < 0.05). CONCLUSIONS: Dyspnea of patients could be immediately relieved after endobronchial stent was inserted. Combined endobronchial and percutaneous radiotherapy obviously alleviated the obstruction caused by trachial or bronchial neoplasms. The results suggested the combined therapy led to much better objective therapeutic effect and symptomatic relief than single percutaneous radiotherapy.

Aged↗
PubMed1999

[Detection and significance of interleukin-16 in sputa from patients with bronchial asthma].

OBJECTIVE: To explore the significance of in the terleukin-16 (IL-16) in pathogenesis of bronchial asthma. METHODS: Induced sputum samples were obtained from 12 allergic asthmatics, 8 non-allergic asthmatics, 10 non-asthma allergic and 10 non-asthma non-allergic normal subjects. ELISA was used to determine the concentrations of IL-16 in sputum, and CD4+ T cells and activated eosinophils (EG2 cells) in sputum were detected by immunostaining. RESULTS: IL-16 levels in both allergic and non-allergic asthmatics were much higher than those in non-asthma allergic or non-asthma non-allergic normal subjects. Effective anti-asthma treatment led to a significant decrease in IL-16 levels in patients with acute asthma. It was also found that the percentages of CD4+ and EG2 cells were all positively correlated to IL-16 levels. CONCLUSIONS: IL-16 is involved in the asthmatic process by recruiting CD4+ T cells and thus plays an important role in CD4+ cell-dependent eosinophilic inflammation in asthmatic airways.

Adult↗
PubMed1999

[RAB5A, a gene possibly related to metastasis of human carcinoma of the lung and stomach].

OBJECTIVE: To study and isolate tumor metastasis-related genes, and to explore the molecular basis of metastasis of lung and gastric carcinoma. METHODS: Using mRNA differential display technique, cDNA cloning and sequencing, RT-PCR, Northern blot and immunocytochemical methods, genes differentially expressed between human lung adenocarcinoma cell lines AGZY83-a and Anip973 were detected. Anip973 was isolated from AGZY83-a with much higher metastatic potential than the parent line. RESULTS: There were significant differences in gene expression between the two cell lines. RAB5A was one of the genes differentially expressed in Anip973 cells. Its gene product is a GTP-binding protein. Paraffin sections of 33 lung carcinoma and 47 gastric carcinoma specimens were examined immunohistochemically. Expression of RAB5A was positive in 87.9% of NSCLC and 91.5% of gastric cancer specimens examined (P < 0.05), and correlated with their metastatic potential and differentiation degree of gastric carcinoma. CONCLUSION: RAB5A is possibly a metastasis-related gene.

Humans↗