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Biomedical subjects

Y Chen

Publications and source records attributed to Y Chen.

At least 667 records · Page 37Linked to original sources
PubMed2001

[Effects of estradiol and isoflavoid on the expression of adhesion molecules on neutrophils].

OBJECTIVE: To elucidate the effects of estradiol and isoflavoid on the expression of adhesion molecules on neutrophils. METHODS: Neutrophils of healthy subjects and ischemic stroke patients were treated with tumor necrosis factor alpha (TNF alpha), in the presence or absence of different concentrations of isoflavoid (WZ1, WZ2) and estradiol (WZ3, WZ4). Flow cytometry was used to detect the expression of CD18 and CD62L on neutrophil surface. RESULTS: 1. 10 ng/ml TNF alpha could activate neutrophils of healthy subjects; it increased the expression of CD18 by 10% on neutrophil surface and shed CD62L from the surface as shown by a 15% decrease of the fluorescence intensity and a 30% decrease of the percentage of positive cell. 2. Isoflavoid (WZ1, WZ2) had no significant effect on the expression of CD18 and CD62L on neutrophils. 3. Pretreatment of neutrophils with estradiol (WZ3, WZ4) could inhibit the activation of neutrophils by TNF alpha, which decreased the fluorescence intensity of CD18 by 8%, increased the fluorescence intensity of CD62L by 15% and increased the percentage of CD62L positive cell by 20%. 4. TNF alpha could activate the neutrophils of ischemic stroke patients strikingly; it increased the fluorescence intensity of CD18 by 20% and decreased the fluorescence intensity and percentage of positive cell of CD62L by 30%, and there was a significant difference when the patients were compared with the healthy subjects. Estradiol had the same effect on the expression of CD18 and CD62L as on those of healthy subjects. CONCLUSION: 1. TNF alpha is a strong activator of neutrophils; it plays an important role in the occurrence and development of ischemic stroke. 2. Isoflavoid has no obvious effect on the expression of adhesion molecules on neutrophils, so its role in protecting the cardiovascular system may come into play not by the way of affecting adhesion molecules expression. 3. Pretreatment of neutrophils with estradiol could protect them from activation by TNF alpha, thus decreasing the expression of adhesion molecules, the adhesion of neutrophils -endothelial cells, and hence the risk of ischemic stroke. However, in case that the neutrophils have been activated by TNF alpha, estradiol has no effect on the expression of adhesion molecules; this implies that estradiol possibly has no valid anti-adhesion therapeutic effect on ischemic stroke.

Adult↗
PubMed2001

[99mTc-Q3 uptake property at varying coronary flow rates in isolated rabbit heart: comparison between 99mTc-Q3 and 201Tl].

OBJECTIVE: This experiment was designed to explore myocardial 99mTc-Q3 uptake property. METHODS: 20 New Zealand White rabbit heart perfusion models were prepared and the isolated rabbit hearts were perfused by double-radionuclide method at varying coronary flow rates from 0.52 to 3.75 ml/g wet wt/min using developed perfusion liquid with autoblood in comparison with 201Tl in the absence of tracers recirculation. RESULTS: Mean 99mTc-Q3 peak instantaneous uptake was lower(0.65 +/- 0.077) and more affected by low rates (P < 0.05) than 201Tl peak instantaneous uptake (0.82 +/- 0.07, P < 0.01). CONCLUSION: These data were interpreted to indicate: 1. 99mTc-Q3 is not as well extracted as 201Tl; 2. varying the coronary flow rate has significant effects on the uptake of 99mTc-Q3 and 201Tl; 3. similarly to 201Tl, the coronary blood flow conditions may be overestimated by the myocardial radioactive uptake acquired with low flow perfusion, but the coronary blood flow conditions may be underestimated by the myocardial radioactive uptake acquired with high flow perfusion. Further studies on retention and clearance of 99mTc-Q3 need to be conducted.

Animals↗
PubMed2001

[Expression of C-myc and N-myc protein in adulthood and childhood medulloblastomas and prognostic analysis].

OBJECTIVE: To detect the expression of C-myc and N-myc in medulloblastomas, the difference between adults and children, and the relation between expression and prognosis. METHODS: ABC immunostaining was used to detect C-myc and N-myc protein expression in 21 cases of adulthood medulloblastomas and 14 childhood cases. Follow-up materials were obtained to perform survival curve analysis. RESULTS: Of these 35 cases, 5 (4 children, 1 adult) showed C-myc positive expression. No N-myc expression was found. There was no relationship between expression and survival. CONCLUSION: C-myc may play a role in the tumorgenesis of medulloblastoma, especially in children, but it is of no prognostic significance. N-myc antigen may be lost during the fixation of specimens.

Adolescent↗
PubMed2001

[Study on bolus cyclosphamide treatment for 64 cases of lupus nephritis].

OBJECTIVE: To report on the dosing, efficacy and side-effects of bolus cyclosphamide treatment for lupus nephritis (LN). METHODS: 64 consecutive cases of LN with 10 or more erythrocytes per high-power field, proteinuria (> 1 g of protein per day) and serum creatinine increased (> 133 mumol/L) were treated by bolus therapy with cyclophosphamide (CTX) given monthly for 6 months and then quarterly for 18 months. RESULTS: 49 patients had renal remission (defined as < 10 erythrocytes per high-power field, absence of cellular casts, excretion of < 1 g of protein per day and normal serum creatinine). The mean of doses was 1.1 g for each time (0.6-1.6 g), the mean of times of bolus CTX needed was 3.6 (1-8 times). The adverse events were amenorrhea (in 41% female patients), herpes zoster (in 13% patients) and hemorrhagic cystitis (in 1 patient). CONCLUSION: The results indicate that monthly bolus CTX therapy is effective and safe for patients with LN. Its adverse effect is relatively not a serious problem.

Amenorrhea↗
PubMed2001

[CT and MRI and clinical study of chordoma in the skull base].

OBJECTIVE: To investigate the diagnostic features of CT and MRI in chordoma of the skull base (CSB) and to estimate their value of clinical application. METHODS: Sixteen patients with CSB were performed CT and MRI examinations of the head, and 13 patients with nasopharyngeal carcinoma (NPC) and 11 patients with pituitary adenoma (PA) which invaded the skull base were selected as control. In addition, 7 cases of chordoma were performed multiple planar reconstruction (MPR) of MRI. RESULTS: MRI was superior to CT in depicting the location and the extent of CSB. The bone destruction at mid-line skull base was demonstrated equally well on both CT and MRI. Based on the location of the tumor displayed on MRI, the CSB could be classified into selloclival, nasopharyngeal, and occipito-temperal types. The T2 weight imaging(T2WI) signal intensity of chordoma was significantly higher than those of NPC and PA (P < 0.01). On MPR images of MRI, oppressed and displaced optic nerves caused by chordoma were noted in 3 cases and encased optic nerves in 4 cases, encased abducent nerves in 7 cases with abducent paralysis and mildly oppressed oculomotor nerves in 3 cases. CONCLUSION: The extremely high T2WI signal intensity is the characteristic of MRI finding in CSB and has great differential value for the tumors of the skull base. The MPR of MRI plays an important role in the surgical treatment for these tumors.

Adult↗
PubMed2001

[Preservative surgery of medial wall pyriform sinus cancer].

OBJECTIVE: To study the surgical methods and functional outcome of preservative surgery for medial wall pyriform sinus cancer. METHODS: Seventy-one patients with medial wall pyriform sinus cancer, who were treated surgically between 1985 and 1997, were reviewed. Of the 71 cases, 49 underwent preservative surgery, and 22 total laryngectomy. Preservative surgical procedure was defined as follows: 1. Extent of resection: Supraglottic horizontal partial laryngectomy and resection of medial wall of pyriform sinus were performed in patients without fixation of the true vocal cord, and the section extended to paraglottic space, partial lateral wall of pyriform sinus, preepigottic space, superior-posterior of thyroid cartilage in those with restrained vocal cord motility. Supracricoid hemilaryngopharyngectomy and resection of medical wall and partial lateral wall of pyriform sinus were practiced in those with fixed hemilarynx. Cricoid ring and cervical esophagus were removed partially if the pyriform sinus apex was involved. 2. Reconstruction: Larynx: the remains of epiglottis, perichondrium of thyroid cartilage, the infrahyoid muscular fascia, and the platysmal flap were utilized to restore the defects of larynx. Pyriform sinus: Suturing the remaining pharyngeal mucosa directly to cover the wound if the defect was relatively small. For the large defect produced by extended resections, the pectoralis major myocutaneous flap and deltopectoral flap were used. 3. Surgical treatment of cervical lymphaden: Sixty five out of the 71 cases (91.5%) underwent neck dissection. Of which ipsilateral neck dissection were done in 39 cases, and bilateral neck dissection in 26 cases. 4. All patients received postoperative radiotherapy with doses of 60-75 Gy. RESULTS: In the group of preservative surgery the 3- and 5-year survival rates were 63.4% and 49.6% respectively, whereas those in the total laryngectomy group were 52.4% and 42.4% respectively. Of the 49 cases with preservative surgery, 71.4% (35/49) had all laryngeal functions restored and 28.6% (14/49) partially restored. CONCLUSION: Despite the fact that the medial wall pyriform sinus cancer tends to have laryngeal invasion, preservative surgery can be practiced for the majority of the cases with the lesions entirely removed.

Adult↗
PubMed2001

[Effects of fermented Cordyceps powder on pulmonary function in sensitized guinea pigs and airway inflammation in sensitized rats].

OBJECTIVE: To study Cordyceps (artificial fermented Cordyceps sinensis(Berk.) Sacc) powderin the treatment of asthma in the animal models. METHOD: Pulmonary function and airway inflammation in vivo were investigated. RESULT: Cordyceps, 5g.kg-1(ig), significantly inhibited bronchial challenge of ovalbumin-induced change of RL and Cdyn (P < 0.05) and inhibited antigen-induced increase of eosinophils in the BALF of rats (P < 0.05). CONCLUSION: The results suggested cordyceps could be applied for the prevention and cure of asthma.

Airway Resistance↗
PubMed2001

Effect of angiotensin II receptor antagonist and endothelin receptor antagonist on nitroglycerin tolerance in rats.

OBJECTIVE: To investigate whether angiotensin II receptor antagonist and endothelin receptor antagonist can improve the nitroglycerin (Nit) tolerance in vivo. METHODS: Twenty-four rats were divided into 4 groups (n = 6, each): Control group, Nitroglycerin (Nit) group, Nit + bosentan group and Nit + losartan group. Nitroglycerin tolerance was induced by 2-day treatment of (10 mg x kg(-1) nitroglycerin patch(0.05 mg/h). Angiotensin receptor antagonist losartan(10 mg x kg(-1) x d(-1)) and endothelin receptor antagonist bosentan (100 mg x kg(-1) x d(-1)) were given by gavage for 2 days respectively. RESULTS: The least hypotensive response to sodium nitroprusside (SNP) was observed in Nit group. The effective percentages of hypotensive response to SNP were increased in both Nit + losartan group and Nit + bosentan group compared with Nit group [(31.95 +/- 4.45) % vs (21.00 +/- 3.69) %, P < 0.01 and (33.18 +/- 6.16) % vs (21.00 +/- 3.69) %, P < 0.01, respectively]. The maximal vessel relaxation induced by SNP was the same in 4 different groups but the highest EC50 (concentration which produces 50% of the maximal response to SNP) was found in tolerant group[(34 +/- 10) nmol/L, P < 0.01]. The ET-1 amounts in plasma and vascular tissue were markedly increased by 54% and 60% in Nit group compared with those in control group( P < 0.01). The ET-1 amounts in plasma and vascular tissue were decreased by 30% and 37% in Nit + losartan group compared with those in Nit group (P < 0.01). CONCLUSION: Endothelin receptor antagonist and angiotensin II receptor antagonist could prevent against the Nit tolerance.

Angiotensin Receptor Antagonists↗
PubMed2001

Urotensin II receptor in the rat airway smooth muscle and its effect on the rat airway smooth muscle cells proliferation.

OBJECTIVE: To investigate the characteristics of urotensin II (U-II) receptor in the rat airway smooth muscle and the effect and signal transduction pathway of U-II on the proliferation of airway smooth muscle cells. METHODS: Using 125I-UII binding assay to measure the Bmax and Kd of U-II receptor. Using the 3H-TdR incorporation to determine the effect of U-II on the proliferation of airway smooth muscle cells and its signal transduction pathway. Using Fura-2/AM to measure the effect of U-1I on the cytosolic free calcium concentration. RESULTS: 1. 125I-UII binding increased with the time and reached saturation at 45 min. The B(max0 was (11.36 +/- 0.37)fmol/mg pr and Kd was (4.46 +/- 0.61) nmol/L. 2. U-II increased 3H-TdR incorporation of the airway smooth muscle cells in a dose-dependent manner. 3. H7, PD98059 and nicardipine, inhibitors of PKC, MAPK, calcium channel, respectively, significantly inhibited U-II-stimulated 3H-TdR incorporation of airway smooth muscle cells. W7, inhibitor of CaM-PK, had no effect. 4. Cyclosporin A, inhibitor of CaN, inhibited 3H-TdR incorporation of the airway smooth muscle cells induced by U-II in a dose-dependent manner. 5. U-II promoted cytosolic free calcium concentration increase by 18%. CONCLUSIONS: 1. There was U-II receptor in the rat airway smooth muscle. 2. The effect of U-II-stimulated 3H-TdR incorporation of airway smooth muscle cells was mediated by such signal transduction pathway as Ca2+, PKC, MAPK and CaN, etc.

Animals↗
PubMed2001

[The Raman spectra study on crystal-octadecyl hydrogen succinate crystal].

Raman spectra of crystal-octadecyl hydrogen succinate (OHS), whose geometric disposition of the experiment has y(zx)y, y(zz)y, and y(xz)y,y(xx)y respectively, have been recorded and analyzed with the purpose of understanding the structure of OHS crystal. It shows that some of the Raman-active modes of alkyl chain appear polarization. The analysis for crystal structure indicates that the molecular of OHS arrange in layers along [100] and [001] by the mode of dimers, and the molecular layers of chain pile up along [010]. The other groups of OHS corresponding Raman vibration peaks have been analyzed as well.

English Abstract↗
PubMed2001

[Determination of lead in whole blood by graphite furnace atomic absorption spectrometry with matrix modifier and L'vov platform].

Lead in whole blood has been determined by graphite furnace atomic absorption spectrometry with matrix modifier and L'vov platform. It's found that addition of the mixture solution of 0.6% NH4H2PO4 and 0.4% NH4NO3 as matrix modifier, the ash temperature will increase up to 900 degrees C. 750 degrees C is practically used for ash temperature. D2 lamp is used for background correction. Lead in whole blood was directly determined after addition of 0.3% Triton X-100 without digestion. The analytical results of six whole samples is satisfactory. The recoveries are 93%-106%. The relative standard deviations are 3%-7%. The sensitivity of characteristic mass is 6.0 pg/1%.

Humans↗
PubMed2001

[Color reaction of chromogenic reagent O-hydroxybenzenediazoaminoazobenzene with thallium (III) and its application].

The chromogenic reaction of the O-hydroxybenzenediazoaminoazobenzene (O-HDAA) with thallium was studied in this paper. In the presence of Triton X-100 and SDBS and in ammonia medium of 0.54-1.1 mol.L-1, O-HDAA reacts with thallium (III) to form a stable red complex with molar radio of 1:5. The apparent molar absorptivity is 1.4 x 10(5) L.mol-1.cm-1 at the maximum absorption wavelength of 520 nm. Beer's law is obeyed in the concentration range of 0-600 micrograms.L-1 Tl(III). The method has been applied to the direct determination of trace amounts of thallium in waste water and in geological samples by using polyurethane foam to absorb and separate Tl(III) with satisfactory results.

Color↗
PubMed2001

[Photoluminescence from Er-doped silicon-rich silicon oxide film and Er-doped silicon-rich silicon nitride film and its annealing behavior].

Room temperature photoluminescence (PL) with a peak at 1.54 microns was observed from silicon oxide, silicon-rich silicon oxide, silicon nitride and silicon-rich silicon nitride films, all doped with Er and grown by the magnetron sputtering technique. To determine the optimum annealing temperature for the 1.54 microns PL, these films were annealed in the range of 600-1,100 degrees C with an interval of 100 degrees C. Among these four types of films annealed at an identical temperature, the intensity of 1.54 microns PL peak of the Er-doped silicon-rich silicon oxide film was always the strongest one, which arrived at a maximum in 800 degrees C annealing. A 1.38 microns PL band was also observed in each of these four types of films, and which in the silicon-rich silicon oxide or silicon-rich silicon nitride films was found to be correlated with the 1.54 microns PL band in intensity.

Chemical Phenomena↗
PubMed2001

Powdery mildew resistance genes in wheat: verification of STS markers.

Five accessions of Aegilops speltoides and 67 European wheat cultivars (winter and spring) originating from the Czech Republic, Germany, Poland, Russia, Slovakia, United Kingdom, and 4 non-European wheat cultivars from Brazil and the USA were examined with molecular Sequence Tagged Site (STS) markers for resistance genes to powdery mildew: Pm 1, Pm 2, Pm 3 and Pm 13. All markers gave clear, repeatable results, although three of them (Pm 1, Pm 2 and Pm 3) appeared as not specific for resistance genes. Comparison of STS analysis results with Pm genes, postulated as the reaction type after inoculation with differential isolates of Erysiphe graminis f.sp. tritici (Blumeria graminis), revealed a high number of disparities. The marker for Pm 13 was not detected in any examined cultivar but was present in five accessions of Aegilops speltoides.

Journal Article↗
PubMed2001

[The levels of interleukin 8 in gingival crevicular fluids of chronic periodontitis].

OBJECTIVE: To study the changes of IL-8 levels in chronic periodontitis progress and correlation with clinical parameters. METHODS: The concentrations and total amounts of IL-8 cytokine in gingival crevicular fluids by double antibody sandwich ABC ELISA in chronic periodontitis (before and after treatment) and healthy control group were determined. Clinical parameters were measured and analysed. RESULTS: In the chronic periodontitis, IL-8 cytokine was detected,significantly higher than the healthy group. The total amounts of IL-8 and GCF had significant differences between the diseased and healthy groups, as well as between the groups before and after treatment (P<0.01, P<0.05, respectively), but no significant difference was found between these groups in the concentration of IL-8 (P>0.05). There was positive correlation between the total amounts of IL-8 and clinical parameters, between GCF volume and clinical parameters (P<0.01). CONCLUSION: These data indicated that the total amounts of IL-8 exhibited dynamic changes upon progress of chronic periodontitis. The levels of IL-8 in GCF are valuable in judging the degree of chronic periodontitis and in guiding clinical treatment.

English Abstract↗
PubMed2001

[Morphologic survey of temporomandibular joint an autopsy investigation].

OBJECTIVES: Understanding the functional structure of temporomandibular joint (TMJ) will be advantageous for us to study the relationship between the occlusal movement and its morphology, and it also will be beneficial for operators of arthroscopy to grasp the relationship between the scope of operation and adjacent landmarks. METHODS: We dissected and measured the TMJ of seven cadavers to study the sizes of condyle and fossa, the oblique angles of their bevel faces and the oblique angles of bevel face of condyle with disc, the distances from midpoint of posterior tragus and cartilage of external auditory canal to the anterior and posterior recess walls. RESULTS: The parameters of the anatomic relationship between condyle, disc, fossa, superior joint space of TMJ and adjacent landmarks were recorded. CONCLUSION: (1) Articular disc coordinates condyle and articular fossa, and increases the condyle anterior bevel's slope which makes them more stable; (2) Transverse ridge of condyle contacts with fossa on point and plane which make lateral motion of condyle more agile; (3) It is important parameter for an operator of arthroscopy to control the depth and range of puncture that measured the distances between anterior and posterior recess walls of upper space in TMJ, the distances from anterior and posterior recess walls to midpoint of posterior tragus and cartilage of external auditory canal, and the size of fossa; Morphology of TMJ is changing with age.

English Abstract↗