Biomedical subjects

G Chen

Publications and source records attributed to G Chen.

At least 307 records · Page 17Linked to original sources

PubMed2000

Human herpesvirus 8 open reading frame 26 and open reading frame 65 sequences from multiple myeloma patients: a shared pattern not found in Kaposi's sarcoma or primary effusion lymphoma.

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus, has been implicated in the pathogenesis of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), multicentric Castleman's disease, and recently multiple myeloma (MM). DNA sequence analyses of HHV-8 suggest that multiple HHV-8 strains exist. We extracted DNA from 24 patients with MM and 3 patients with monoclonal gammopathy of undetermined significance and compared HHV-8 open reading frames (ORFs) 26 and 65 sequences with those derived from patients with KS, PEL, and two HHV-8-positive PEL cell lines KS-1 and BC-1. ORF26 sequence data suggest that MM patients are consistently carriers of HHV-8 strain subtype C3. All MM patients also consistently revealed either a single bp deletion or substitution at position 112197 in ORF65. This unique alteration is not present in patients with KS or PEL or in PEL cell lines. It occurs in the portion of ORF65 that is known to be responsible for a serological response to HHV-8.

Amino Acid Sequence↗

PubMed2000

[Status of methylation of promoter of mis-match repair gene hMLH1 in lung cancer].

OBJECTIVE: To study the relationship between status of methylation of hMLH1 promoter and expression of its protein in lung cancer. METHODS: Methylation of the hMLH1 gene promoter and hMLH1 protein was examined in 50 primary lung cancer tissues by Hpa II digestion-PCR and immunohistochemistry. RESULTS: The incidence of the hMLH1 promoter methylation was 32.0% (16/50). Methylation frequeney did not correlate with sex, smoking and clinicopathological characteristics. Negative expression of hMLH1 protein occurred in 14/46 tumors, of which 11 tumors had hMLH1 promoter methylation (78.6%, 11/14), while only 5 had methylation in 32 specimens positive for hMLH1 protein expression. CONCLUSION: In about one-third of lung cancer tissues examined there exists methylation of hMLH1 promoter, which correlates well with the absence of expression of hMLH1 protein.

Adaptor Proteins, Signal Transducing↗

PubMed2000

Clinical observation on the long-term therapeutic effects of traditional Chinese medicine for treatment of liver fibrosis.

48 patients with liver fibrosis due to hepatitis B were treated for 2 years with the drugs for tonifying the kidney, supplementing qi, cooling and invigorating the blood and detoxification. The symptoms were markedly improved, and serum ALT and bilirubin were recovered and kept normal in most of the cases. The mean levels of serum hyaluronic acid, procollagen peptide III and circulating immune complex were decreased and returned to normal after the treatment. B-ultrasonography showed that the portal vein kept in normal size in 82% of the patients, the enlarged portal vein diminished in diameter, and the enlarged spleen reduced.

Adult↗

PubMed2000

[The expression of P16 and Rb proteins in 106 cases of lung cancer].

OBJECTIVE: To observe the relationship between the expression of P16 and Rb proteins and the proliferation of lung cancer cells. METHODS: The expressions of P16 and Rb proteins were measured in 66 cases of NSCLC and 40 cases of SCLC by means of immunohistochemistry technique. RESULTS: The inverse correlation of Rb and P16 proteins expression was confirmed in 66 cases of NSCLC (chi 2 = 10.52, P < 0.01). No relationship between the expression of P16 and differentiation, stage, lymph node metastasis or pathological type was found (P > 0.05). There was no correlation between the expression of Rb and differentiation, stage, lymph node metastasis or pathological pattern (P > 0.05). The frequency of the loss of Rb protein expression in SCLC (78%) was significantly higher than in NSCLC (21%, chi 2 = 32.3, P < 0.01). CONCLUSIONS: Loss of Rb protein expression in SCLC may be an important marker of the diagnosis of SCLC. The expression of P16 adversely correlates with that of Rb. This study provides strong confirmation about that there might be a negative feedback between P16 and Rb in phase G1.

Aged↗

PubMed2000

[Antibody to human herpesvirus type-8 in the general populations of Xinjiang Autonomous Region(A.R.)].

OBJECTIVE: Kaposi 's sarcoma (KS) does not rarely occur in Xinjiang A. R. Much of the evidence show that human herpes virus-8 (HHV-8) is associated with KS, and the different incidence of classic KS among different countries reflects the different prevalence in general populations. The aim of this study was to know whether the prevalence of HHV-8 is higher in general populations of Xinjiang than the other places of the country. METHODS: We used BCBL-1 cell line as antigen and collected 1071 serum sample of different nationalities (Uighur, Khalkhas, Kazak and Han nationality) from south and north regions of Xinjiang A. R. for detection of HHV-8 IgG antibody by IFA. RESULTS: The results showed that HHV-8 IgG antibody positive rate in Khalkhas was 48% (96/200), Uighur 30.4%(62/204), Kazak 12.5% (25/200) and Han 16.9% (79/467). While sera were diluted in 1:20, the positive rate in Khalkhas still was as high as 30.5% (61/200). In addition, the positive rate of HHV-8 IgG antibody in minorities in the same native area all were higher than Han except Kazak nationality. CONCLUSIONS: These data illustrated that the prevalence of HHV-8 IgG antibody in general populations of different nationality was different, Khalkhas and Uighur were higher than Kazak and Han. Most of the KS cases were reported from Uighur nationality, but no case was reported from Khalkhas thought a highest HHV-8 IgG antibody detection rate (48%) there was demonstrated. The reason for it would be further studied.

Adolescent↗

PubMed2000

[Effect of modified ammonium bicarbonate on nitrification-denitrification process and NO and N2O emission].

Compared with ammonium bicarbonate(AB), the effect of modified ammonium bicarbonate (MAB) on nitrification and denitrification processes and NO and N2O emissions in a clay soil (C soil) and a loam soil (L soil) was studied in laboratory (25 degrees C and 50% WFPS). The inhibition effect of DCD from MAB on nitrification was relatively small in C soil, but considerably great in L soil. Compared with AB, MAB extended 7 days and 33 days for retaining NH4+. During 15 days, the NO emission from C soil and L soil respectively accounted for 0.60% and 1.06% of applied N under AB application (100 micrograms N.g-1), which were as 30 and 12 times as the N2O emission from corresponding soils. After applying MAB, the emission of NO from C soil and L soil decreased by 67% and 95%, and the emission of N2O decreased by 64% and 95%, respectively. After 39 days of aerobic incubation, then anaerobically flooded incubation with nitrate addition (200 micrograms KNO3-N.g-1) for 7 days, the total loss of denitrification in MAB in L soil was 50% less, and N2O emission was 113% more than in AB in same soil.

Benzidines↗

PubMed2000

[Effect of different watering and fertilization on N utilization efficiency].

The comprehensive effects of the timing of watering and N and K fertilization(D), amount of irrigated water(W), and application rates of chemical N and K fertilizers, and farm manure(M) were studied by the design of orthogonal regression rotation with five factors and five levels under dry greenhouse condition. The N utilization efficiency of potato was in order of N > W > D > M > K. Under different application rates of W, N, K and M, the N utilization efficiency was significantly increased with optimum timing of watering and fertilization. When the application rate was low, the timing should be earlier, while it was high, the timing should be later. High application rates of W and N resulted in the best interaction effect, with 57.83% of N utilization efficiency; moderater W and N or low W and N had 29.17-40.99% of efficiency; and high W and low N or low W and high N resulted in the lowest efficiency, with 22.87% and 22.51%, respectively.

Fertilizers↗

PubMed2000

Production and reduction of nitrous oxide in agricultural and forest soils.

A soil-water slurry experiment was conducted to study the potentials of N2O production and reduction in denitrification of agricultural and beech forest soils in Denmark. The effects of nitrate and ammonium additions on denitrification were also investigated. The forest soil showed a higher denitrification potential than the agricultural soil. However, N2O reduction potential of the agricultural soil was higher than the beech forest soil, shown by the ratio of N2O/N2 approximately 0.11 and 3.65 in the agricultural and the beech forest soils, respectively. Both nitrate and ammonium additions stimulated the N2O production in the two soils, but reduced the N2O reduction rates in the agricultural soil slurries. In contrast to the effect on the agricultural soil, nitrate reduced the N2O reduction rate in the beech forest soil, while ammonium showed a stimulating effect on the N2O reduction activity. After one week incubation, all of the N2O produced was reduced to N2 in the agricultural soil when nitrate was still present. Nitrous oxide reduction in the beech forest soil occurred only when nitrate almost disappeared. The different nitrate inhibitory effect on the N2O reduction activity in the two soils was due to the difference in soil pH. Inhibition of nitrate on N2O reduction was significant under acidic condition. Consequently, soil could serve as a sink of atmospheric N2O under the conditions of anaerobic, pH near neutral and low nitrate content.

Crops, Agricultural↗

PubMed2000

[Grey system analysis on dominant natural enemies influencing Aphis gosspyii population].

The populations of Aphis gosspyii and its natural enemies before cotton boll stage were investigated systematically in 1983, 1984, 1986, 1988, 1994 and 1995. The relationship between daily total predation of natural enemies and Aphis gosspyii population size was studied with the grey system theory and method, and the relational grade of various natural enemies to ideal superior natural enemies was analyzed. The results show that Propylaca japonica was the major natural enemy influencing Aphis gossypii, followed by Chrysopa septempunctata, then by Therdion octomaculatum and Erigonidium graminicola.

Animals↗

PubMed2000

[Geostatistical analysis on spatial patterns of Aphis gossypii and Propylaca japonica].

The spatial construction and distribution of Aphis gossypii and Propylaca japonica at different period were investigated with geostatistics. The results showed that the semivariogram of Aphis gossypii was described by spherical model, indicating an aggregated spatial arrangement, the range was 8.21-10.81 m. The semivariograms of Propylaca japonica was fitted by spherical model too, also indicating an aggregated spatial arrangement, its range was 8.01-14.25 m. The amount and spatial distribution of Propylaca japonica was closely related to that of Aphis gossypii. It reveals that Propylaca japonica is dominant natural enemies of influencing population of Ahphis gossypii.

Animals↗

PubMed2000

[Effect of rhTFAR19 protein on cell cycle and apoptosis of MCF-7 induced by gamma-ray].

OBJECTIVE: To investigate the effect of protein product of TFAR19, an apoptosis-related gene previously cloned from leukemia cell line TF-1 cultured in medium deprived of growth factor, on cell cycle and apoptosis of human breast cancer induced by gamma-ray. METHODS: Cell morphology, fluorescence microscopy, laser scanning confocal microscopy, single-cell gel electrophoresis (SCGE) and flow cytometry (FCM) were applied to study cell cycle and apoptosis of breast cancer cell line MCF-7. RESULTS: rhTFAR19 protein itself had no effect on cell cycle arrest and apoptosis of MCF-7 cell induced by gamma-ray. When MCF-7 cells were pretreated with 10 micrograms/ml rhTFAR19 and then irradiated with 12 Gy gamma-ray, cell apoptosis was observed. It was characterized morphologically by chromatin condensation, nucleoar disintegration, formation of apoptotic bodies, and typical "cornet" on SCGE. CONCLUSION: TFAR19 protein has no apparent effect on MCF-7 cell cycle induced by gamma-ray. However, it synergizes with gamma-radiation in the induction and enhancement of apoptosis.

Apoptosis↗

PubMed2000

[The relationship between sensitivity to arsenic trioxide and antioxidative capacity of malignant hematopoietic cells].

OBJECTIVE: To detect the relationship between sensitivity of malignant hematopoietic cells to arsenic trioxide (As2O3) and cellular capacity against oxidation. METHODS: Nine cell lines derived from hematopoietic malignancies were treated with As2O3 in vitro. Apoptosis was assessed by cellular viability, cytomorphology and flow cytometry. The As2O3-treated cells were examined for glutathione (GSH) level and activity of catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST) and glutathione peroxidase (GPX). RESULTS: Of the 9 cell lines examined, the acute promyelocytic leukemia cell line NB4 and its retinoic acid-resistant subclones R2 and MR2, the Burkitt lymphoma cell line Namalwa and multiple myeloma cell line RPMI 8226 were sensitive to As2O3-induced apoptosis while the acute T cell leukemia cell line (Jurkat) and 3 cell lines (HL-60, U937, K562) of myelogenous leukemia origin were not. In comparison with the sensitive cell lines, higher activity of CAT was found in HL-60 and U937, higher level of GSH in Jurkat, and both in K562. However, activity of GPX, GST and SOD did not significantly correlate with their resistance to As2O3-induced apoptosis. CONCLUSION: Intracellular GSH level and/or catalase activity are important factors to determine sensitivity of malignant hematopoietic cells to As2O3-induced apoptosis.

Apoptosis↗

PubMed2000

[Clinical significance of sentinel lymph node biopsy in breast cancer].

OBJECTIVE: To study the necessity, feasibility, accuracy and clinical value of sentinel lymph node(SLN) biopsy in the management of breast cancer. METHODS: Technetium-99m labeled colloid particles were injected subcutaneously below the breast tumor before mastectomy. The sentinel lymph nodes identified by lymphoscintigraphy and gamma-counter were dissected out from the excised axillary tissue and separately examined manually for consistency and histologically. RESULTS: In 30 cases studied, SLNs were identified in all but one, with a detection rate of 96.7%. Metastases were detected in SLNS in 8 cases. The other case showed positive axillary lymph nodes but SLN was negative. The sensitivity of SLN biopsy in this study was 88.9%, accuracy was 93.3%, false positive was 0, false negative was 11.1%. CONCLUSION: SLN biopsy, though still under investigation, may in the future substitute routine axillary lymph node dissection in the management of breast cancer.

Adult↗

PubMed2000

[The relationship between HCY-2 gene and congenital heart teratogenesis in early chick embryos].

OBJECTIVE: To explore the relationship between novel gene (HCY-2), homocysteine and congenital heart defects, and to study their biological mechanisms. METHODS: The teratogenic test of chick embryos which were treated with D.L-homocysteine (0.16 micromol/embryo) was used to observe the developmental toxicity of homocysteine per se. The eukaryotic expressing vector containing whole-length HCY-2 cDNA (2 014 bp) was microinjected into fertile eggs with lipofect AMINE(TM) reagent; then the effects of HCY-2 gene on cardiovascular damages of embryos, the expression and distribution of HCY-2 gene coding product were investigated with the techniques of Western blot, immunohistochemistry, light and electron microscopy. RESULTS: Apparently teratogenic action of homocysteine on developing heart was observed in the critical stage of organogenesis and the damages were concentration dependent (P < 0.05). 10 approximately 20 microgram HCY-2 gene could cause dysmorphogenesis of the cardiovascular system. The congenital heart defect rates were 16.7% and 24.0% respectively. The abnormal forms were ectopic cardis extrathoracic heart and hypoplastic heart. Western blot and immunohistochemical staining showed that HCY-2 protein was largely expressed in the abnormal embryos, with stronger staining at the sites of embryonic heart and brain as compared with controls. Under light and electron microscope, it was seen that HCY-2 gene resulted in structure disturbance, endocardial cushion defect and hypoplasia of heart. CONCLUSION: Homocysteine/HCY-2 gene may be a new heart-developing cytotoxic/genotoxic factor, and HCY-2 gene may play a very important role in the mechanisms of congenital heart defects of chick, and probably humans as well.

Animals↗

PubMed2000

[Effects of arsenic trioxide on K562 cells stably expressing two promyelocytic leukemia-specific fusion proteins].

OBJECTIVE: To illustrate the possible roles of acute promyelocytic leukemia-specific chimeric proteins PML-RARalpha and PLZF-RARalpha in the effects of arsenic trioxide (As(2)O(3)). METHODS: K562 sublines stably expressing PML-RARalpha (K(PML() and PLZF-RARalpha (K(PLZF)) were established by retrovirus transfection with K(V) transfected empty vectors as controls. Effects of As(2)O(3) and all-trans retinoic acid (ATRA) on these sublines were analyzed through cell count, morphology, measurement of cellular DNA contents and differentiation antigens on flow cytometry. Subcellular distributions of PML-RARalpha proteins were observed with immunofluorescence. RESULTS: 1.0 micromol/L of As(2)O(3) did not induce cell apoptosis and differentiation, but it significantly inhibited the growth of K(V) sublines. As(2)O(3) showed the similar but more potent effects in K(PML) and K(PLZF) sublines. 1.0 micromol/L As(2)O(3) treatment for 3 days induced growth inhibition by 32% +/- 3%, 57% +/- 4% and 54% +/- 6%, respectively in K(V), K(PML) and K(PLZF) sublines. 1.0 micromol/L ATRA also exerted, to a less extent than As(2)O(3), growth-inhibitory effects in K(V) sublines, which became more obvious in K(PML) but not in K(PLZF) sublines. In addition, PML/PML-RARalpha proteins were decreased and even disappeared in K(V) and K(PML) sublines with the treatment of 1.0 micromol/L As(2)O(3) for 48 hours. CONCLUSION: PML-RARalpha and PLZF-RARalpha markedly enhance growth-inhibitory effects of As2)O3) on K562 cells.

Antineoplastic Agents↗

PubMed2000

[The expression and effects of isoforms of macrophage colony stimulating factor in human leukemic cell lines].

OBJECTIVE: To explore the expression and effects of isoforms of macrophage colony-stimulating factor (M-CSF) in human leukemic cell lines. METHODS: Three normal human peripheral blood mononuclear cells (PBMCs) and 4 human myelomonocytic leukemic cell lines including J6-1, J6-2, K562 and HL-60 were studied using ABC immunoperoxidase assay, indirect immunofluorescence staining, flow cytometry, Western blot and reverse enzyme-linked DNA-protein interaction assay (reverse ELDIA). RESULTS: M-CSF was noticed to be localized in the cytoplasm, nucleus and at the cell membrane in 4 human leukemic cell lines; expression of M-CSF was not detected in normal human PBMCs without PHA stimulation. Human PBMCs stimulated by PHA expressed a low level of M-CSF. Frequencies of membrane bound M-CSF expression in J6-1, J6-2, K562 and HL-60 were 71.6%, 69.7%, 42.7% and 57.4% respectively. Frequencies of cytoplasm and nucleus associated M-CSF were 65.7%, 45.4%, 36.5% and 72.5% respectively. The cytosolic bound M-CSF was expressed in J6-1 cell as four isoforms with a molecular weight of 14,000, 16,000, 20,000 and 44,000. While nucleus associated M-CSF expressed as two isoforms with a molecular weight of 16,000 and 20,000. Anti-M-CSF monoclonal antibody could dramatically inhibit proliferation of leukemic cells and its inhibitory effect was related to the levels of membrane bound M-CSF expression in leukemic cells. Reverse ELDIA showed that M-CSF could bind with DNA in vitro. CONCLUSIONS: Expression of M-CSF isoforms is heterogeneous and polymorphous in leukemic cells. Membrane bound M-CSF is crucial for the proliferation of leukemic cells, which might be a DNA-bound protein and could be involved in the transformation and tumorigenesis of hematopoietic cells.

Antibodies, Monoclonal↗

PubMed2000

[The inhibition of prourokinase gene transfer on deposition of platelets on rabbit carotid artery intima].

OBJECTIVE: To observe the expression of pro-urokinase (proUK) gene in rabbit carotid artery transfected with replication-deficient adenovirus vector containing proUK gene (Ad/prouk) and the deposition of platelet on the same injured vessel. METHODS: Ad/proUK (Ad/proUK, 3 x 10(10) pfu/ml) was injected into the right carotid artery locally. Wild type adenovirus (Ad) was locally injected into the left carotid artery as self-control. The expression of proUK gene was investigated by immunohistochemistry assay. After injury of the gene-transfected vessel by electric stimulation, the deposition of (111) In-labeled platelet was quantitatively observed. The thrombosis was observed with HE-stained vessel section. RESULTS: There were lots of proUK granules in the endothelium of Ad/proUK gene-transfected vessel. The differences in (111) In-platelets deposition per gram dry weight vessel segment were significant between Ad/proUK and Ad transfected control vessels [(4.60 +/- 0.93) x 10(7)/g vs control (27.95 +/- 4.93) x 10(7)/g, P < 0.01)]. The HE-stained vessel section showed that there were only small thrombi in proUK gene-transfected vessel but massive thrombi almost blocked up the whole vessel in control vessel. CONCLUSION: The proUK gene-transfected vessel can obviously inhibit (111) In-labeled platelet deposition on injured vessel and thus thrombosis.

Adenoviridae↗

PubMed2000

[Study of the expression and function of c-kit receptor on the bone marrow mononuclear cells of the patients with myelodysplastic syndromes].

OBJECTIVE: To determine the expression and function of c-kit receptor on bone marrow mononuclear cells (BMMNC) of the patients with myelodysplastic syndromes. METHODS: c-kit protein (CD(117)) was detected by direct immunofluorescence assay, c-kit mRNA by reverse transcriptive polymerase chain reaction (RT-PCR) and the function of c-kit receptor by cell culture. RESULTS: c-kit protein expression in MDS was significantly higher than that in control [(8.58 +/- 5.28)% vs (3.04 +/- 1.49)%, P < 0.05]. c-kit protein expression in RA patients was significantly lower than that in RAEB/RAEB-t patients [(5.12 +/- 2.13)% vs (10.01 +/- 5.07)%, P < 0.05]. The rate of c-kit protein expression was (32.43 +/- 18.16)% in AML cases transformed from MDS (t-AML). c-kit mRNA expression in MDS was correlated with c-kit protein expression. Addition of interleukin-3 (IL-3), erythropoietin (Epo) and stem cell factor (SCF) to the semi-solid culture of BMMNC showed significant stimulating effects on CFU-GM and BFU-E formation in normal controls, but did not in MDS patients. CONCLUSION: The protein and mRNA expressions of c-kit receptor on BMMNC in MDS are higher than those in normal control, and the function of this receptor in MDS is abnormal.

Adolescent↗