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Biomedical subjects

D X Chen

Publications and source records attributed to D X Chen.

At least 19 recordsLinked to original sources
PubMed2006

Increased glycophorin A somatic cell variant frequency in arsenic-exposed patients of Guizhou, China.

Exposure to arsenic through domestic burning arsenic-containing coal causes various tumors in a population of Guizhou, China. The glycophorin A (GPA) assay is a human mutation assay detecting somatic variation in erythrocytes expressing the MN blood type, and was used to assess genotoxicity of arsenic-exposed patients. Peripheral blood was collected from 18 adult healthy subjects and 40 arsenic-exposed patients in heparin-treated tubes. Erythrocytes were isolated, fixed in formalin and immuno-labeled with fluorescent antibodies against GPA, followed by flow cytometry analysis. Arsenic exposure increased the variant frequency (expressed as the number of variant red cells per 10(6) erythrocytes): NN, 3.7 in healthy subjects versus 21.2 in arsenic-exposed patients; N phi, 12.6 versus 33.1; MM, 13.1 versus 110; and M phi, 5.2 versus 20.3. The total GPA variant frequency was increased about five-fold (34.7 in healthy subjects versus 185 in arsenosis patients). Furthermore, the variant frequency was significantly higher in skin tumor-bearing patients: NN, 19.4 in arsenic-exposed non-tumor patients versus 31.5 in tumor-bearing patients; N phi, 29.5 versus 54.5; MM, 102 versus 159; M phi, 15.9 versus 45.1. Total GPA variant frequency in arsenic-exposed patients bearing skin tumors was significantly increased compared to patients without skin tumors (167 versus 290). The relationship between arsenic exposure history and GPA variant frequency was less evident. These data demonstrate that arsenic exposure is associated with mutations at the GPA locus, an effect exaggerated in patients bearing arsenic-induced skin tumors. The variant frequency of GPA could be a useful biomarker for arsenic exposure and arsenic carcinogenesis.

Adult↗
PubMed2004

Optimization of submerged culture requirements for the production of mycelial growth and exopolysaccharide by Cordyceps jiangxiensis JXPJ 0109.

AIMS: The objective of the present study was to investigate the optimal culture requirements for mycelial growth and exopolysaccharide production by Cordyceps jiangxiensis JXPJ 0109 in submerged culture. METHODS AND RESULTS: The effects of medium ingredients (i.e. carbon and nitrogen sources, and growth factor) and other culture requirements (i.e. initial pH, temperature, etc.) on the production of mycelia and exopolysaccharide were observed using a one-factor-at-a-time method. More suitable culture requirements for mycelial growth and exopolysaccharide production were proved to be maltose, glycerol, tryptone, soya bean steep powder, yeast extract, medium capacity 200 ml in a 500-ml flask, agitation rate 180 rev min(-1), seed age 4-8 days, inoculum size 2.5-7.5% (v/v), etc. The optimal temperatures and initial pHs for mycelial growth and exopolysaccharide production were at 26 degrees C and pH 5 and at 28 degrees C and pH 7, respectively, and corresponding optimal culture age were observed to be 8 and 10 days respectively. According to the primary results of the one-factor-at-a-time experiments, the optimal medium for the mycelial growth and exopolysaccharide production were obtained using an orthogonal layout method to optimize further. Herein the effects of medium ingredients on the mycelial growth of C. jiangxiensis JXPJ 0109 were in the order of yeast extract > tryptone > maltose > CaCl2 > glycerol > MgSO4 > KH2PO4 and the optimal concentration of each composition was 15 g maltose (food-grade), 10 g glycerol, 10 g tryptone, 10 g yeast extract, 1 g KH2PO4, 0.2 g MgSO4, and 0.5 g CaCl2 in 1 l of distilled water, while the order of effects of those components on exopolysaccharide production was yeast extract > maltose > tryptone > glycerol > KH2PO4 > CaCl2 > MgSO4, corresponding to the optimal concentration of medium was as follows: 20 g maltose (food-grade), 8 g glycerol, 5 g tryptone, 10 g yeast extract, 1 g KH2PO4, and 0.5 g CaCl2 in 1 l of distilled water. CONCLUSIONS: Under the optimal culture requirements, the maximum exopolysaccharide production reached 3.5 g l(-1) after 10 days of fermentation, while the maximum production of mycelial growth achieved 14.5 g l(-1) after 8 days of fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report on the submerged culture requirements for mycelial growth and exopolysaccharide in C. jiangxiensis, and this two-step optimization strategy in this study can be widely applied to other microbial fermentation processes.

Carbon↗
PubMed1993

[Clinical analysis of tooth fracture trauma by masticatory occlusion]

About 185 tooth fracture cases among 184 patients,it was found that tooth fracture happened on misticatory occlusion almost follows the regulation at the same tooth which has suffered of damage,such as dental caries,wedge shaped defect and cracked tooth and so on.The position of tooth damage is that of tooth fracture as well.The range and extent effect obviously on the tooth fracture.The terminal point of fracture line is related closely to pulp condition.It's considered that the out force is the major direct cause of tooth fracture,while position,extent,range and pulp condition before fracture is the main inner inducement fact.

Journal Article↗
PubMed1992

[Extensive and radical surgery for primary ovarian cancer].

From 1983 to 1990, 34 cases of primary ovarian cancer were treated with extensive and radical surgery. Seventeen cases belonged to stage I, 3 cases belonged to stage II and 14 cases were stage III. They consisted of 20 epithelial, 11 germ cell and 2 sex-cord tumors of ovary. The operative method was as follows: infracolic omentectomy, para-aortic and pelvic lymphadenectomy, dilateral salpingo-oophorectomy, total hysterectomy, removing of metastatic implants nd appendectomy. Post surgery, all patients received repeated combination chemotherapy and six cases received irradiation. Four patients underwent the second look operation. The incidence of metastasis of contralateral ovary, omentum, retroperitoneal nodes, uterus, fallopian tubes and appendix were 38.2%, 32.4%, 20.6%, 17.6%, 5.9% and 2.9% respectively. The 3 year survival rate of stage I and II was 92.9%, stage III was 40.0%. The 5 year survival rate of stage I and II was 90.9%, stage III was 50.0%. There was no serious complication both intra and post operation.

Adolescent↗
PubMed1991

Factors influencing ablation of atherosclerotic plaque with argon laser.

The ablative effect of argon laser delivered fibreoptically in vitro on 234 segments of atherosclerotic human aorta was studied. The variables such as energy density, type of atheroma and immersion media were included, and all irradiated specimens were subsequently submitted to histological examination and crater volumes in mm3 to micrometer measurements under light microscope. The results showed 1) a linear relationship between energy dose and crater volume in fibrous atheroma, 2) significantly greater damage or surrounding in the higher energy dose groups, 3) a lower dose response in calcified tissue than in fatty streaks or fibrous atheroma, and 4) immersion of tissue in blood during ablation resulted in a significantly greater dose response than immersion in plasma or saline, and the corresponding surrounding tissue damage was greatest when immersed in blood. Thus, argon laser is both effective and predictable in response during ablating of atheromatous tissue. The efficacy of the process is dependent on immersion medium, while the degree of surrounding tissue damage is dependent on energy dose.

Angioplasty, Laser↗
PubMed1990

Differences in the phagocytosis of four bacteria by channel catfish neutrophils.

The purpose of this study was to compare the phagocytosis of Aeromonas hydrophila, Edwardsiella ictaluri, Edwardsiella tarda and Micrococcus luteus by channel catfish neutrophils. Various aspects of opsonization effect and bactericidal ability of channel catfish neutrophils were investigated. Percent phagocytosis ranged from a low of 1% to a high of 91%. The highest percent phagocytosis and phagocytic indices routinely occurred with normal serum and were highest for M. luteus (91.78%, 55.25) and A. hydrophila (87.52%, 43.60). In all cases, the percent phagocytosis and phagocytic index was lowest in assays without serum. Channel catfish neutrophils displayed a bactericidal/static ability for each bacterium tested except E. tarda. Neutrophils exhibited a greater inhibitory capacity for A. hydrophila and M. luteus than for the other bacteria when in the presence of normal or inactivated catfish serum.

Aeromonas↗
PubMed1990

Saliva and serum CA 125 assays for detecting malignant ovarian tumors.

The aim of this study was to determine whether CA 125 was present in saliva and, if it was present, to compare saliva and serum levels in patients with pelvic masses in order to determine whether saliva assays would be useful in identifying patients with ovarian malignancies. Saliva and serum CA 125 levels were assayed in specimens obtained from 55 normal healthy women, 92 patients with benign pelvic masses, and 41 patients with malignant pelvic tumors. We defined a serum CA 125 value greater than 65 U/mL and a saliva CA 125 value greater than 3000 U/mL as the positivity criteria. No serum or saliva assay was positive in the 55 normal women. The sensitivities of the saliva and serum CA 125 assays in 16 patients with epithelial ovarian cancer were 81.3 and 93.8%, respectively. A linear correlation was observed between serum and saliva CA 125 levels. The false-positive rates of serum CA 125 in patients with endometriomas and pelvic tuberculosis were 72.7 and 80%, respectively, but the false-positive rates for saliva CA 125 assays were only 13.6 and 10%, respectively. Therefore, the saliva CA 125 assay had a better diagnostic value than the serum CA 125 assay. In addition, collection of saliva is simple, noninvasive, and inexpensive, and samples could be obtained easily and repeatedly. For these reasons, assays of saliva CA 125 levels may be a new way of screening for malignant ovarian tumors.

Adult↗
PubMed1990

[Primary research on saliva and serum CA125 assays for detecting malignant ovarian tumors].

Saliva and serum CA125 levels were assayed in specimens obtained from 55 normal healthy women, 92 patients with benign pelvic masses and 41 patients with malignant pelvic tumors. A saliva CA125 value greater than 3,000 kU/ml and serum CA125 value greater than 65 kU/ml were defined as positive. Only one saliva assay was positive in 55 normal women. The sensitivity of saliva and serum CA125 assays in 16 patients with epithelial ovarian cancer was 81% and 94% respectively. A linear correlation was observed between serum and saliva CA125 levels in 32 patients with malignant ovarian cancer. The false positive rate of saliva and serum CA125 assays in patients with endometriomas and pelvic tuberculosis was 13.6%, 10% and 72.7%, 80% respectively. Therefore, the saliva CA125 assay had better diagnostic value than the serum CA125 assay. In addition, collection of saliva is simple, noninvasive, and inexpensive and could be obtained repeatedly. For these reasons, assays of saliva CA125 levels may provide a new way of screening for malignant ovarian tumors.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1989

A study of the monoclonal antibody OC 125 to diagnose malignant ovarian tumors.

Serum CA 125 was assayed preoperatively in 40 patients with ovarian malignancies and in 44 normal individuals. The correlation between CA 125 and tumor histology, tumor burden, ascites, and the clinical stage was analyzed. CA 125 levels greater than 65 U/ml were defined as positive. The results revealed normal values in each of the 44 normal individuals. CA 125 was elevated in 35 of 40 (87.5%) patients with malignant ovarian tumors including 23 of 24 (95.8%) patients with epithelial ovarian cancers, 7 of whom had stage I disease. Serum CA 125 was also elevated in 12 of 16 (75%) patients with nonepithelial ovarian malignancies. The results suggest that the CA 125 level can be correlated with tumor histology, tumor burden, and ascites but not with clinical stage.

Antibodies, Monoclonal↗
PubMed1989

Determination of glucose-6-phosphate dehydrogenase isoenzymes of human erythrocytes by a thin-layer PAG-IEF procedure.

A procedure of thin-layer PAG-IEF was employed to separate glucose-6-phosphate dehydrogenase (G6PD) isoenzymes of human erythrocytes into 15-16 bands in a pH range between 4.7 and 6.5. The G6PD isoenzymes were scanned with a dual-wavelength thin-layer chromatoscanner and the relative enzyme content of each band was calculated. The method possesses the merits of simplicity, high sensitivity, rapidity and high reproducibility.

Chromatography, Thin Layer↗
PubMed1989

[A preliminary study on in vitro fertilization and embryo transfer].

Forty-two women with infertility were enrolled in an in vitro fertilization and embryo transfer (IVF/ET) program, from July, 1986 to February, 1988, at the First Affiliated Hospital, Human Medical University. CC/hMG/hCG and hMG/hCG regimens for ovulation induction were used for 35 and 7 patients. Monitoring methods consisted of daily follicular ultrasonography and serum estradiol measurements. Human chorionic gonadotropin 10,000IU was administered when the leading follicle reached 18mm in diameter and serum E2 level was equal to or more than 1,480 pmol/L (400 pg/ml). Twenty-one laparoscopies and nineteen laparotomies for oocyte retrieval were performed. The IVF/ET results using CC/hMG/hCG for ovarian stimulation were as follows: an average of 6.1 follicles were aspirated and 3.5 oocytes recovered for one case. The recovery rate and fertilization rate was 57.0% and 60.1% respectively. In twenty-five women one to five embryos were transferred and a clinical pregnancy occurred in one who received three embryos. Laparotomy for oocyte retrieval showed that more oocytes could be obtained than laparoscopy. The purity of CO2 used for laparoscopy was considered to affect the IVF results.

Adult↗
PubMed1989

[Urinary complications following radical hysterectomy for 621 patients with cancer of uterine cervix].

The chief urinary complications following radical hysterectomy for 621 patients with cervical cancer are reported. Bladder and ureteral injury occurred in 0.16% and 0.64% of patients. The incidence of ureteral fistula was also very low (0.16%). Temporary retention of urine was one of the most common urinary complications with occurring rate of 43%. The incidence was related to the type of radical hysterectomy. The incidence of urinary tract infection was 14.33% which was related to the retention of urine. The results of urine culture showed that the main pathogens of infection were B. aeruginosus and Escherichia coli. Impairment of kidney function, usually unilateral, was the major late urinary complication. The severity, causes and prevention of urinary complications are briefly discussed.

Female↗
PubMed1988

Evaluation of CA 125 levels in differentiating malignant from benign tumors in patients with pelvic masses.

Serum CA 125 levels were assayed from 44 normal healthy women, 153 patients with benign pelvic masses, and 58 patients with malignant pelvic masses. CA 125 levels were less than 35 U/mL in 42 of the 44 normal women and were greater than 35 but less than 65 U/mL in the other two women. Among 153 patients with benign pelvic masses, CA 125 levels greater than 35, 65, or 194 U/mL were detected in 61 (39.9%), 31 (20.3%), and eight (5.2%) patients, respectively. Of 58 patients with malignant pelvic masses, CA 125 results were greater than 35, 65, or 194 U/mL in 48 (82.8%), 45 (77.6%), and 38 (65.5%), respectively. Among the latter group, the positivity rates of 30 patients with epithelial ovarian cancers were 100, 93, and 80%, respectively. This study suggests that defining positive serum CA 125 levels as those greater than 35 U/mL is of limited clinical value because there is a 39.9% false-positive rate in patients with benign disease. However, serum CA 125 values greater than 65 U/mL may be considered positive in clinically normal women. Serum CA 125 greater than 194 U/mL, representing the units at the 95th percentile for 153 patients with benign pelvic masses, is defined as a new positivity criterion, and could be used to differentiate malignant tumors from benign pelvic masses.

Adult↗