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Biomedical subjects

J Chen

Publications and source records attributed to J Chen.

At least 595 records · Page 33Linked to original sources
PubMed2001

c-Kit (CD117) reactivity in extramedullary myeloid tumor/granulocytic sarcoma.

CONTEXT: c-kit, a proto-oncogene, encodes the transmembrane tyrosine kinase receptor CD117 and is detected by flow cytometry in the majority of cases of acute myeloid leukemia. The prognostic significance of the presence of c-Kit in acute myeloid leukemia is debated. Recently, c-kit inhibitors have been studied as possible therapies against hematopoietic malignancies; therefore, c-Kit detection may have important implications for treatment. OBJECTIVES: In this study, we investigated the expression of c-Kit in granulocytic sarcoma (GS) using paraffin-embedded tissue. DESIGN: Routinely formalin-fixed, paraffin-embedded tissues from 30 cases of GS were studied using immunohistochemistry. c-Kit (C-19) (a polyclonal antibody against carboxy terminal domain of c-Kit p145 or CD117) reactivity was compared with myeloperoxidase and lysozyme. The immunohistochemical panel also included CD34, CD68, CD43, Bcl-2, CD45RB, CD20, CD3, CD10, terminal deoxynucleotidyl transferase (TdT), and CD79a. RESULTS: The morphologic patterns included well-differentiated (5 cases), poorly differentiated (19 cases), and blastic forms (6 cases). Clinical data were obtained from 28 of 30 patients. Granulocytic sarcoma presented in lymph nodes in 10 cases, whereas in 20 cases it presented in extranodal sites. c-Kit reactivity was found in 87% (26/30) of the GS cases. There was no significant difference in c-Kit positivity between the nodal (90%, 9/10) and extranodal (85%, 17/20) neoplasms. c-Kit expression was not associated with the degree of the myeloid maturation. Two of 13 lymphoblastic lymphoma control cases and 1 of 28 of the large B-cell lymphomas were weakly immunoreactive with c-Kit. CONCLUSIONS: c-Kit reactivity can be demonstrated in a high percentage of GS cases; its presence may be useful not only in diagnosis, but also in the treatment of GS with new modalities.

Adolescent↗
PubMed2001

Clinical efficacy of sildenafil in patients on chronic dialysis.

PURPOSE: We evaluate the clinical efficacy of sildenafil citrate for patients who are on chronic dialysis and who have concomitant erectile dysfunction. MATERIALS AND METHODS: A total of 35 men (mean age 60.7 years) on dialysis and with erectile dysfunction of various etiologies were administered 25 to 100 mg sildenafil for at least 6 months. The International Index of Erectile Function questionnaire (IIEF), a global assessment question and partner satisfaction question were used to evaluate sildenafil efficacy. Patients also reported any adverse events that occurred during treatment. RESULTS: Treatment was effective for 28 of the 35 (80%) patients according to the results of the IIEF and global assessment questions. Partner satisfaction correlated with the IIEF overall response (0.79) and global assessment question results (0.86). No correlation was found between sildenafil failure and patient age, the etiology of erectile dysfunction, duration of erectile dysfunction, prior treatments, testosterone and prolactin blood levels, and the duration and etiology of renal failure. Of the 35 patients sildenafil was stopped due to intolerable headaches in 3 and because of lack of efficacy in 7. CONCLUSIONS: Sildenafil is an effective and safe treatment for erectile dysfunction in most patients on chronic dialysis.

Aged↗
PubMed2001

"Hybrid" revascularization: video-thoracoscopy assisted MIDCAB combined with angioplasty.

A "hybrid" revascularization technique has been developed for cases in which a chronic total occlusion of the left anterior descending coronary artery (LAD) cannot be recanalized by percutaneous coronary intervention, but the lesions in the right coronary artery and/or left circumflex artery are very good candidates for angioplasty. This technique, which uses video-thoracoscopy assisted minimally invasive direct coronary artery bypass to recanalize the occluded LAD and angioplasty to dilate favorable lesions in other vessels, would achieve complete revascularization in selected patients with multi-vessel disease. In this preliminary study of four patients, angioplasty and stenting were successful in all patients without any complications; complete revascularization was achieved in all 4 patients. No recurrence of angina and no cardiovascular events developed during follow-up; this study therefore supports the belief that the "hybrid" revascularization technique is both feasible and safe.

Adult↗
PubMed2001

[Effect of vitamin E on morphological variation of retinal ganglion cells after microwave radiation].

To determine the morphological variation in the primary cultured pig retinal ganglion cells induced by microwave and the protection of VE can supply some experiment foundation for study of effect of microwave and its protection. Retinal ganglion cells of pig were cultured in vitro and added VE of different concentration, Each group was taken after 30 mW/cm2 microwave intensity radiated for 1 h in shielded room by 2450 MHz continuous wave physiotherapy machine. Immediately after radiation, the morphological variation of cells was observed by optics microscope and transmission electronic microscope. The result showed that a portion of cells congregated, with their axon disappeared after radiation. Mitochondria and endoplasmic reticulum are detected swelling by transmission electronic microscope. The results showed that A poptosis cells can be observed. Cells of VE added groups had not obvious changes with optics microscope, but could be found that mitochondria swelling lightly and integrate mitochondria cristae by transmission electronic microscope. The results showed that microwave induced the morphological damage in primary cultured retinal ganglion cells, VE could reduced the damage of retina ganglion cells by microwave in some extent.

Animals↗
PubMed2001

[Study on the inhibition of tea pigments on the adhesion between monocyte and endothelial cells].

In order to study the effects of tea pigments (TP) on the adhesion between monocyte and endothelial cells induced by oxidized low density lipoprotein(Ox-LDL), the fluorescence activated cell sorter (FACS) and the cell ELISA were applied. The results showed that TP could inhibit the adhesion between monocyte and endothelial cells(P < 0.05), and the expression of inter cell adhesion molecule(ICAM-1) and vascular cell adhesion molecule (VCAM-1) proteins in a dose dependent manner(P < 0.05). The results suggested that the inhibition of TP on ICAM-1 and VCAM-1 expression was one of the mechanisms of its antiadhesion between monocyte and vascular endothelial cells, as well as that of its antiatherosclerosis.

Cell Adhesion↗
PubMed2001

Comparative genomics of microbial drug efflux systems.

The complete genome sequences of 36 microorganisms have now been published and this wealth of genome data has enabled the development of comparative genomic and functional genomic approaches to investigate the biology of these organisms. Comparative genomic analyses of membrane transport systems have revealed that transporter substrate specificities correlate with an organism's lifestyle. The types and numbers of predicted drug efflux systems vary dramatically amongst sequenced organisms. Microarray and gene knockout studies to date have suggested that predicted drug efflux genes often appear to be a) non-essential and b) expressed at detectable levels under standard laboratory growth conditions.

Bacteria↗
PubMed2001

[Effect of zinc on adrenocorticotropic hormone secretion in the pituitary cell line AtT-20].

The effect of zinc on adrenocorticotropic hormone (ACTH) secretion in the pituitary cell line AtT-20 was studied. Different concentrations of zinc(10(-8) to 1 mmol/L) were added to the medium and ACTH was determined 12 hours later. The findings revealed that zinc within certain concentrations could promote the secretion of ACTH in AtT-20 cells.

Adrenocorticotropic Hormone↗
PubMed2001

[Permeabilization of yeast Trigonopsis variabilis FA10 cells for enhancing apparent activity of D-amino acid oxidase].

D-amino acid oxidase(DAO) is an intracellular enzyme in Trigonopsis variabilis FA10. The whole cells of yeast exhibited very low DAO activity. Various treatment with physical and chemical agents, such as, freezing and thawing, acetone, butanol and cetyltrimethylammoinium bromide altered membrane permeability and increased cellular DAO activity. It was demonstrated that the performance of acetone was dependent on the concentration of the solvent, the incubation time and the temperature. Maximum enzyme activity of the cells was achieved with 30-35% acetone, between 4 degrees C and 28 degrees C. The process was very quick and permeabilization occurred in 5 minutes or less. On the other hand, the thermostability of DAO in permeabilized cells was higher than in cell extract. It was proved that Cephalosporin C could be effectively converted to glutaryl-7ACA by permeabilized Trigonopsis variabilis cells with 83% yield.

D-Amino-Acid Oxidase↗
PubMed2001

[Expression of human brain derived neurotrophic factor gene in E. coli].

The primers specific for the full-length BDNF coding sequence was designed and synthesized. The BDNF coding sequence was directly amplified from human genomic DNA by using PCR and inserted into vector pGEM-3Zf(+). The recombinant DNA was transformed into the host cells JM109 to obtain the positive clone pGEMBF18. The restriction enzyme analysis and DNA sequence detection confirmed that the inserted fragment of clone pGEMBF18 is the full-length BDNF coding sequence. The hBDNF DNA fragment was recovered from the clone pGEMBF18 and ligated with prokaryotic expression vector pGEX-5T to construct the recombinant expression plasmid p5TBF34. The E. coli JM109 transformed with p5TBF34 was induced with IPTG. A new protein band with apparent molecular weight 43 kDa was detected in the lysate of the transformed cell by using SDS-PAGE. The result of western hybridization showed that this fusion protein reacted specifically to the antibodies to human BDNF. The amount of the soluble fusion protein was about 503.04 mg/L lysate, 7.53% of total bacterial soluble protein of transformed cells, estimated by absorbance scanning of SDS-PAGE and protein quantitation.

Brain-Derived Neurotrophic Factor↗
PubMed2001

[A resource investigation and commodity identification of Fructus Amomi].

Resource investigation and commodity identification were carried out for 28 samples of Fructus Amomi collected from 7 provinces. The results showed that Fructus Amomi used currently were mainly from the dried ripe-fruit of Amomum villosum, A. villosum var. xanthioides or A. longiligulare. Fructus Amomi in market is nainly A. villosum which comes from Yunnan and Guangdong province.

China↗
PubMed2001

Biomarker studies on gold-lined sea bream (Rhabdosargus sarba) exposed to benzo[a]pyrene.

Gold-lined sea bream (Rhabdosargus sarba) were intraperitoneally injected with 35 mg/kg benzo[a]pyrene (in DMSO), with fish administered DMSO as the solvent control. Fish were sacrificed 3 days post injection and their livers dissected for the analysis of adenosine triphosphates (ATPase), glutathione-S-transferase (GST), DNA adducts and ethyoxyresorufin-O-deethylase (EROD). Exposure to B[a]P resulted in reduced ATPase activity, elevated GST activity and DNA adduct level, but no apparent change in EROD activity.

Adenosine Triphosphatases↗
PubMed2001

Operational control of storm sewage at an activated sludge process.

Operational control of storm sewage at a wastewater treatment plant has attracted intensive concern over the last decade in the context of river basin management. The focus is on the exploitation of the full capacity of the wastewater treatment plant in attenuating storm sewage, and minimizing a direct storm sewage bypass to the river. Attention is particularly paid to the surge of storm water on the activated sludge process. Based on two typical rain events, this paper discusses the performance of several practical controllers in achieving an optimal effluent performance under storm loadings, without risking internal biomass stability and sludge overflow. The control algorithms tested include various controls of recycle rate, step-feed and step-sludge. Prediction errors of influent characteristics and process responses are also under consideration in the assessment. The results illustrate well the desirability, effectiveness and robustness of the tested controllers.

Algorithms↗
PubMed2001

Effect of percent free prostate-specific antigen measurement on improving the specificity of serum prostate-specific antigen testing in Taiwanese patients.

BACKGROUND AND PURPOSE: Measurement of percent free prostate-specific antigen (fPSA) has been shown to enhance the diagnostic performance of traditional serum PSA determination. We sought to determine whether measurement of percent fPSA could improve the specificity of serum total PSA testing in the detection of prostate cancer in Taiwanese patients with intermediate serum PSA concentrations. METHODS: The medical records of 211 patients examined from March 1998 through March 2000 were analyzed retrospectively; all had a serum total PSA concentration of between 4.1 and 20.0 ng/mL and negative digital rectal examination (DRE) findings, and had undergone a prostate biopsy. Biopsy results were correlated with the serum total PSA concentration and percent fPSA, which were determined using a microparticle enzyme immunoassay. Percent fPSA was calculated as the ratio of fPSA to total PSA multiple by 100. The sensitivity and specificity were calculated and the receiver operating characteristic (ROC) curves were generated from different cutoff values of percent fPSA and total PSA. RESULTS: Thirty-four patients (16.1%) had positive biopsy results (prostate cancer). Patients with positive biopsy results had significantly lower percent fPSA values than those with negative results (11.7% vs 16.0%, p < 0.001). Patients with a lower percent fPSA (< 10%) had a higher probability of a positive biopsy result than those with a high percent fPSA (> 20%) (positive biopsy rate, 29% vs 10%, p < 0.05). Using a cutoff value of 25% fPSA or below, the sensitivity, specificity, and positive predictive value in differentiating patients with positive biopsy results from those with negative results were 97%, 13%, and 18%, respectively. Consequently, 27 unnecessary biopsies could have been avoided at the cost of missing one cancer. The area under the ROC curve was 0.68 for percent fPSA and 0.63 for total PSA (p > 0.05). CONCLUSIONS: For Taiwanese patients with a serum PSA concentration of between 4.1 and 20.0 ng/mL, the incidence of prostate cancer is relatively low; measurement of percent fPSA only weakly enhances the specificity of serum PSA testing in detecting prostate cancer.

Aged↗
PubMed2001

Effectiveness of transperitoneal and trans-retroperitoneal laparoscopic adrenalectomy versus open adrenalectomy.

PURPOSE: This study compared the effectiveness of laparoscopic adrenalectomy, using either a transperitoneal or trans-retroperitoneal approach, with that of open adrenalectomy in patients with benign adrenal tumors. METHODS: From February 1995 to April 2000, laparoscopic adrenalectomy was performed on 31 patients with adrenal tumors, including 16 aldosteronomas, 10 Cushing's adenomas, three nonfunctioning tumors, and two pheochromocytomas. A lateral trans-retroperitoneal approach was used for the first 16 patients and a lateral transperitoneal approach was used for the last 15 patients. Twenty-one patients who received open adrenalectomy during the same period served as a control group. Comparisons were made between laparoscopy and open groups, and between transperitoneal and trans-retroperitoneal groups. RESULTS: Conversion to open adrenalectomy was necessary in two cases--both in the trans-retroperitoneal group during the first 2 years of the study period. No other intraoperative complications occurred and blood transfusion was not used. Compared with the open group, the laparoscopic group had less blood loss (71 vs 124 mL), resumed oral feeding earlier (28 vs 60 hr), required less postoperative narcotics (45 vs 120 mg meperidine), and had shorter postoperative hospital stays (4.9 vs 7.6 days) (all p < 0.05). The mean operative time was longer in the laparoscopic group (203 vs 123 min, p < 0.001). There were no significant differences between the transperitoneal and trans-retroperitoneal laparoscopy groups in any of the studied parameters, except that the operative time was longer in the trans-retroperitoneal laparoscopy group (244 vs 166 minutes, p < 0.01). CONCLUSIONS: Decreased blood loss, less postoperative pain, earlier resumption of oral feeding, and shorter hospital stays were achieved in patients undergoing laparoscopic adrenalectomy. These findings indicate that laparoscopic adrenalectomy is the treatment of choice for benign adrenal tumors. The transperitoneal approach yielded shorter operative time than the trans-retroperitoneal approach, because it offered a clearer view and familiar landmarks.

Adrenalectomy↗
PubMed2001

[Primary discussion on the imported materia medica].

The features, with respect to medical use, dosage form, manufacture technology and quality, of licensed imported materia medica and botanical preparation in market were discussed in this paper. The international market competition of Chinese Materia Medica was analyzed, and the countermeasure to resist the imported materia medica was also included.

Drugs, Chinese Herbal↗
PubMed2001

In utero ethanol exposure causes mitochondrial dysfunction, which can result in apoptotic cell death in fetal brain: a potential role for 4-hydroxynonenal.

BACKGROUND: In utero ethanol exposure causes abnormal fetal brain development that may partly be due to enhanced cell death. The mechanisms underlying this remain to be defined, but ethanol-induced oxidative stress may play a role. The following studies investigated the effects of short-term in utero ethanol exposure on fetal brain mitochondrial events that are known to elicit apoptotic cell death. Evidence is presented suggesting that 4-hydroxynonenal (HNE), a toxic product of lipid oxidation, is a causal factor in the observed mitochondrial damage. METHODS: Mitochondria were isolated from control and ethanol-exposed fetal brains (days 17 and 18 of gestation). Permeability transition was determined spectrophotometrically, and cytochrome c and apoptosis-inducing factor (AIF) release were assessed by Western blotting. Caspase-3 activity and DNA fragmentation were determined both as markers for mitochondrially mediated apoptosis and as consequences of cytochrome c and AIF release. RESULTS: Maternal ethanol intake caused an increase in mitochondrial permeability transition, and this was accompanied by cytochrome c and AIF release from fetal brain mitochondria that exceeded control values by 62 and 25%, respectively (p < 0.05). In utero ethanol exposure resulted in a 30% increase in caspase-3 activity and a 25% increase in DNA fragmentation (p < 0.05) in the fetal brain. HNE levels were increased by 23% (p < 0.05) in mitochondria by in vivo ethanol exposure. In vitro treatment of fetal brain mitochondria with HNE (25-100 microM) also caused increases in mitochondrial permeability transition, as well as dose-dependent releases of cytochrome c and AIF. CONCLUSIONS: These studies illustrate that in utero ethanol exposure can elicit a cascade of events in the fetal brain that are consistent with mitochondrially mediated apoptotic cell death. Additionally, the increase in mitochondrial content of HNE after ethanol intake and the ability of HNE added to fetal brain mitochondria to mimic these effects of in vivo ethanol exposure support a potential role for HNE in the proapoptotic responses to ethanol.

Aldehydes↗