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Biomedical subjects

W Zhang

Publications and source records attributed to W Zhang.

At least 325 records · Page 18Linked to original sources

[Use of microsatellites in zygosity diagnosis of twins].

OBJECTIVE: To diagnose zygosity of twins by microsatellite polymorphism. METHODS: One hundred and eighty-four samples, including 69 pairs of twins with the same gender and 6 pairs of twins with different gender were recruited. Seventeen sib pairs were also collected for controls. Nine highly polymorphic microsatellite loci were amplified by polymerase chain reaction (PCR) using fluorescence-labeled primers and the products were sized by automated fragment analysis after electrophoresis and laser detection. Zygosity was diagnosed by comparing the concordance of the genotype of the 9 markers. RESULTS: Sixty-three pairs of monozygotic (MZ) and 12 pairs of dizygotic (DZ) twins were assigned their zygosity by comparison of polymorphism of 9 microsatellite loci. Within each of the 63 monozygotic (MZ) pairs there was complete concordance. However, within each of the 12 dizygotic pairs and other 17 sib pairs, discordant loci were found. With five or six markers, the probability that any twin pair was MZ if all markers were concordant was 99% or 99.6%, respectively. With all the nine markers, the probability that any twin pair was MZ if all markers were concordant was 99.95%. CONCLUSION: The technology of gene scan and genotyping provides a rapid and reliable approach to zygosity detection.

DNA↗

Laryngeal and hypopharyngeal carcinoma: comparison of helical CT multiplanar reformation, three-dimensional reconstruction and virtual laryngoscopy.

OBJECTIVE: To evaluate the clinical application of helical CT multiplanar reformation (MPR) three-dimensional reconstruction (3D) and virtual laryngoscopy (CTVL) in laryngeal and hypopharyngeal carcinoma. METHODS: Axial helical CT scans were performed in 22 patients with laryngeal or hypopharyngeal carcinoma, along with MPR, 3D and CTVL. These results were compared with the findings of fiber optic laryngoscopy and surgery. RESULTS: Combining axial and MPR images, both the accuracy in preoperative tumor staging and the diagnosis of metastatic lymph nodes were 95%. MPR demonstrated more information about the extent of tumor than axial images in 23% cases; 3D image displayed clearly the extension of tumor, the vessels and airway from multiple views. The location, size and extent of tumors found in cranio-caudal CTVL corresponded well with that of laryngoscopy, and CTVL demonstrated the relationship between the tumor and vocal cords and anterior commissure by caudo-cranial approach, which was inaccessible to fiber optic laryngoscopy in 3 cases. CONCLUSIONS: Axial images of helical CT clearly demonstrate the location, size and extent of laryngeal and hypopharyngeal carcinoma, while MPR and 3D images are useful in displaying the three-dimensional images and anatomical relation of the tumor. CTVL can clearly display the mucosal surface structures of the larynx and hypopharynx and is a good complementary method of laryngoscopy.

Adult↗

Endocytic routes of exogenous antigen in murine dendritic cells and macrophages.

OBJECTIVE: To compare the endocytic routes of exogenous antigen between murine dendritic cells (DCs) and macrophages (M phi s). METHODS: Murine bone marrow-derived DCs and peritoneal M phi s were pulsed with horseradish peroxidase (HRP)-5 nm colloidal gold for 10 minutes, then grouped and chased for 0-120 minutes in culture medium. Intracellular distribution of 5 nm colloidal gold was explored by means of the cellular enzymatic-chemistry of acid phosphatase and MHC II immuno-cytochemistry under electron microscope. RESULTS: After 10 minutes of pulse with HRP-5 nm colloidal gold and 30 minutes of chase, most HRP-5 nm gold particles internalized by DCs entered into MHC class II compartments (M II Cs), and a small portion entered into acid phosphatase-positive lysosomes. In contrast to DCs, most M phi s lysosomes were accessed by HRP-5 nm gold particles, and a small portion of HRP-5 nm gold particles entered into M II Cs. After 60 minutes of chase, 5 nm gold particles could hardly be seen within M phi s, whereas most 5 nm gold particles were still retained in DCs. CONCLUSIONS: The endocytic route of exogenous antigen in DCs seems to be different from that in M phi s. Antigens taken by M phi s mainly enter into lysosomes within 30 minutes. In the case of DCs, most internalized antigens enter into M II Cs, which may be related to their unique antigen-presenting function. In addition, M phi s seem to have more powerful capacity to scavenge exogenous antigen than DCs.

Acid Phosphatase↗

Sodium channels in the apical membrane of human nasal epithelial cells.

OBJECTIVE: To study the electrophysiological properties of sodium channels in the apical membrane of human nasal epithelial cells. METHOD: Nasal epithelial cells of human inferior turbinate from patients with obstructive sleep apnea syndrome were cultured in serum free medium on collagen gel-coated membranes at an air-liquid interface and studied by a patch clamp technique. RESULTS: In cell-attached patches, a typical single channel current with a conductance of 21.09 pS and reversal potential of -50.96 were recorded. The permeability ratio PNa/PK was more than 5.80. In the presence of 10(-4) mmol/L amiloride in the pipette, the incidence of sodium channels decreased from 26.67% to 5.13%. This revealed that a population of channels were inhibited by amiloride at a dose of 10(-4) mmol/L. Ca2+ at dose of 10(-3) mmol/L did not influence the incidence of sodium channels. There was no obvious association between voltage and the open probability of the channels. CONCLUSIONS: Our results indicate that most Na+ channels in cell-attached patches of human nasal epithelial cells are amiloride-sensitive and Na+ selective. Only a few channels are amiloride-insensitive. The channels were not activated by extracellular Ca2+ and the open probability followed a voltage-independent manner.

Amiloride↗

Placental leptin correlates with intrauterine fetal growth and development.

OBJECTIVE: To study the role of placental leptin in intrauterine cord leptin production and its relationship with neonatal anthropometry. METHODS: Forty women and their babies (40) were enrolled in this study. Placental tissues were assayed for leptin mRNA by reverse transcription/polymerase chain reaction (RT/PCR), and assayed for the obese gene protein leptin by Western-blot and immunohistochemistry. Blood was taken from the umbilical cord of the babies at delivery. Serum leptin was measured by radio-immunoassay. Neonatal anthropometric measurements were recorded within 48 hours after delivery. Linear regression analysis was used to explore the relationship between placental leptin, cord leptin and neonatal anthropometric measures. RESULTS: The obese gene was expressed in placental tissue at comparable or greater levels than that in adipose tissue. The placentas of the small for gestational age (SGA) neonates expressed leptin mRNA and protein at significantly lower levels than those of the appropriate for gestational age (AGA) neonates (P = 0.0034 and 0.0076), while the placentas of the large for gestational age (LGA) neonates expressed leptin mRNA and protein at significantly higher levels than those of the AGA neonates (P = 0.043 and 0.021). Linear regression analysis showed placental ob gene transcription and leptin translation correlated significantly with cord leptin (r = 0.39 and 0.43), and neonatal Ponderal Index (r = 0.66 and 0.69). CONCLUSION: The placenta provides a source of leptin for the growing fetus, and this placental leptin might be a growth factor in intrauterine fetal development.

Blotting, Western↗

[Differences of nitric oxide synthase expression and activity between splanchnic arterial and venous vessels of cirrhotic rats].

OBJECTIVE: To understand the implication of differences of nitric oxide synthase (NOS) expression and activity between splanchnic arterial and venous vessels in the pathogenesis of portal hypertension. METHODS: Cirrhosis was induced in 100 Wistar rats by subcutaneously administration of carbon tetrachloride. NOS localization, activity and gene expression in the mesenteric artery and the portal vein vessels of both cirrhotic and normal rats were investigated by immunohistochemistry, chemoluminescence and reverse transcription-polymerase chain reaction, respectively. RESULTS: There was inducible NOS enzyme isoform in al1 layers of splanchnic vessels of cirrhotic rats, whereas endothelial NOS isoform largely in vascular endothelia. NOS activity and its mRNA expression all were significantly increased in cirrhotic rats when compared with normal rats (P<0.05 or 0.01).Moreover, the activities of general and constitutive NOS and the expression of endothelial NOS mRNA in cirrhotic rats were significantly higher in the mesenteric artery than in the portal vein (P<0.01). CONCLUSIONS: Enhanced expression and activity of endothelial NOS enzyme isoform may be mainly responsible for increased NO production of splanchnic vessels in cirrhotic rats, and the differences of NOS expression and activity between the mesenteric artery and the portal vein vessels may be one of the pathogeneses of portal hypertension in which NO might be involved.

Animals↗

[Abnormal expression of p53, Ki67 and iNOS in human esophageal carcinoma in situ and pre-malignant lesions].

OBJECTIVE: To investigate alterations in expression of Ki67, p53 and iNOS proteins in esophageal carcinogenesis. METHODS: The expression of Ki67, p53 and iNOS proteins was detected by immunohistochemical staining of 366 endoscopic biopsy specimens of the esophagus collected from high incidence area of esophageal cancer in China. If the intensity of staining was scored as > or = ++, it was regarded as overexpression. RESULTS: The overespression rate of Ki67 was 0 for normal epithelium(NE), 2.7% for mild dysplasia (MD), 11.2% for moderate dysplasia (MoD), 41.2% for severe dysplasia (SD), and 58.8% for carcinoma in-situ(CIS), respectively. That of p53 and iNOS proteins was 0 and 0 for NE, 10.1% and 4.0% for MD, 24.5% and 7.5% for MoD, 39.2% and 2.5% for SD, 48.7% and 1.4% for CIS, respectively. There was significant difference in the expression of Ki67 and p53 between normal epithelium and dysplasia of various degrees and CIS. Overexpression of Ki67 and p53 correlated well with the pathological grading of the lesions. Positive correlation was also found between p53 and Ki67 overexpressions. CONCLUSION: Overexpression of Ki67 and p53, but not iNOS, is associated with carcinogenesis of the esophagus. They are early events in esophageal carcinogenesis and useful biomarkers for early detection.

Carcinoma in Situ↗

[CT virtual bronchoscopy in the diagnosis of central lung cancer].

OBJECTIVE: To evaluate the clinical application of CT virtual bronchoscopy(VB) in the diagnosis of centrally located lung cancer. METHODS: Forty-five cases confirmed by fiberoptic bronchoscopy and pathology underwent volume scanning using spiral CT (HiSpeed Advantage CT/i. GE Medical Systems, U.S.A). The patients examined included 33 with central lung cancer, 8 with post-operative residual bronchial stumps, 2 with post-radiotherapy lung cancer, and 2 with tracheal carcinoma. Data were transferred to computer workstation (GE Advantage Windows 3.1) and CT virtual bronchoscopic (CTVB) images with pseudocolor encoding were generated using Navigator Smooth soft-ware. RESULTS: CTVB could reveal 100% segmental bronchus and 80% subsegmental bronchus simulating fiberoptic bronchoscopy. The tumors appeared as masses or nodules, causing bronchial wall thickening and occlusions. Post-operative residual bronchial stumps showed smooth end without recurrence of tumors or appeared as nodular protrusion if tumor recurred. The post-radiotherapy bronchial wall was uneven and there was narrowing of bronchial lumen. CONCLUSION: CTVB is a noninvasive method of observing the airway. It stimulates the images observed under fiberoptic bronchoscopy and com be used partly in lieu of it. Associated with multiplanar reformat, CTVB can demonstrate extraluminal invasion of the tumor. The limitations of CTVB are that it is not possible to observe mucosal abnormalities and perform biopsy.

Adult↗

[A study on cyclooxygenase-2 protein expression in esophageal carcinoma and premalignant lesions].

OBJECTIVE: To investigate cyclooxygenase-2(Cox-2) protein expression in esophageal cancer and precancerous lesions. METHODS: One hundred twenty biopsy specimens from patients with esophageal carcinoma, 113 from patients with esophageal premalignant lesions, 27 from individuals with normal esophageal mucosa and 3 from Barrett's esophagus were examined for Cox-2 protein expression by immunohistochemistry. RESULTS: Cox-2 protein was not observed in normal esophageal squamous and glandular epithelium, hyperplasia from mild to severe dysplasia lesions and carcinoma in situ. Positive Cox-2 expression was found in 4 of 60 specimens of invasive squamous-cell carcinomas, 21 of 30 specimens of esophageal adenocarcinomas and in 3 of 3 Barrett's esophageal tissues. CONCLUSION: The Cox-2 protein expression may be associated with the development of the esophageal adenocarcinomas but not esophageal squamous-cell carcinomas.

Adenocarcinoma↗

[The clinical usefulness of helical CT multiplanar reformation, three-dimensional reconstruction and virtual laryngoscopy in laryngeal and hypopharyngeal carcinomas].

OBJECTIVE: To evaluate the clinical applications of helical CT multiplanar reformation (MPR), three-dimensional reconstruction (3D) and virtual laryngoscopy (CTVL) in laryngeal and hypopharyngeal carcinoma. METHODS: Axial helical CT scan was performed in 24 patients with laryngeal or hypopharyngeal carcinoma, meanwhile MPR, 3D and CTVL were performed on each patient. The results were compared with the fiberoptic laryngoscopic and surgical findings. RESULTS: Axial helical CT combined with MPR images, the accuracy of preoperative tumor staging and detection of metastatic lymph nodes were both 96%. In 25% of the cases, MPR was more informative than axial images about the extent of tumor invasion. The 3D image three-dimensionally displayed the extent of tumor invasion, and its relation to blood vessels and airway. On CTVL, the location, size and extent of intraluminal tumors of the larynx and hypopharynx when observed from above corresponded well with those observed under laryngoscope. In 4 patients, CTVL observed from below, demonstrated the relationship between the tumor and vocal cords and anterior commissure inaccessible to fiberoptic laryngoscopy. CONCLUSION: Helical CT axial scanning combined with MPR, 3D and CTVL images, can provide more comprehensive information about laryngeal and hypopharyngeal carcinoma.

Adult↗

[Mammaglobin mRNA measurement in the detection of micrometastasis in peripheral blood of breast cancer patients].

OBJECTIVE: To investigate mammanglobin (hMAM) mRNA as a marker for the detection of carcinoma cells by reverse transcriptase chain reaction (RT-PCR) in the peripheral blood of breast cancer patients. METHODS: Blood samples from 63 breast cancer patients obtained at various stages of their disease, blood samples from 8 breast hyperplasia, 5 breast adenofibroma, 25 other cancers (stomach, colon, esophagus, lung, ovary) and 31 healthy volunteers were screened for hMAM mRNA by a nested RT-PCR combined with fluorescence quantitative PCR (FQ-PCR) assay. RESULTS: Among 63 breast carcinoma patients, 19(30.2%) were RT-PCR positive for hMAM mRNA which was elevated with the tumor stage. None of the other cancer patients or those suffering from benign breast diseases were positive but only 1 of the 31 healthy volunteers gave detectable hMAM mRNA findings. hMAM mRNA was not detectable in the peripheral blood after operation in 6(32%) of 19 patients whose pre-operative test had been positive even though the hMAM mRNA expression increased with tumor stage. These results did not correlate with patients' stage, estrogen or pregnant receptor status. CONCLUSION: hMAM transcripts are detectable in the peripheral blood of some breast cancer patients. hMAM may be a novel candidate and a clinically useful breast tumor marker, especially in detecting micrometastasis.

Breast Neoplasms↗

[Telomerase activity in cervical intraepithelial neoplasia].

OBJECTIVE: To investigate the relationship between telomerase expression and the carcinogenesis of cervix, and the possibility of using telomerase as a marker to evaluate the natural history of cervical intraepithelial neoplasia (CIN). METHODS: Use the telomere repeat amplification protocol (TRAP) assay to detect cervical lesion in cervical scraping samples and cervical biopsy tissues. RESULTS: Sixty two point five percent, 60.0 percent, 82.4 percent and 61.9 percent cervical scraping samples exhibited telomerase activity in CINI, CINII, CINIII and cervical cancer, respectively, compared 50.0 percent, 45.0 percent, 96.4 percent and 95.2 percent in cervical biopsy tissue. In contrast, 20.0 percent and 26.7 percent in cervical scraping samples and cervical biopsy tissues of normal cervix. With the development of cervical lesion, the expression of tolemerase activation was increasing (P < 0.05). There was no significant difference between CINI and CINII (P > 0.05). There were significant differences between CINIII and CINI, CINII (P < 0.05) Telomerase activity was coincidence between the cervical scraping samples and cervical biopsy tissues. CONCLUSIONS: These results seem to suggest that the Telomerase expression may associate with the carcinogenesis of cervix. The telomerase activity assay of cervical scraping sample could be used as a marker to monitor and predicate the transit of CIN in clinical practice.

Adult↗

Point mutations of muscle mitochondrial DNA from patients with mitochondrial encephalomyopathies.

OBJECTIVE: To study the relation between point mutations at nt3243 and nt8344 of muscle mitochondrial DNA from patients with mitochondrial encephalomyopathies and phenotypes. METHODS: DNA was extracted from muscle specimens from 5 patients with mitochondrial encephalomyopathies and and amplified by PCR method, using corresponding oligonucleotide primers. DNA fragments were digested with restriction enzymes Bgl I and Apa I, then the digested DNA fragments were analyzed with an electrophoresis method. RESULTS: The point mutation at nt3243 of mtDNA was found in 2 patients, one with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) and another with myoclonic epilepsy with ragged red fibers (MERRF). The point mutation at nt8344 was found in 2 patients with MERRF, including the one with point mutation at nt3243. CONCLUSION: The point mutation of DNA at nt3243 correlated with MELAS and nt8344 correlated with MERRF. In addition, the detection of point mutations at both nt3243 and nt8344 in a patient with MERRF shows the association of mutation with diversity in clinical manifestations of mitochondrial encephalomyopathies.

Adolescent↗

[A study on the relations of soluble interleukin-2 receptor and CD+25 cell with acute graft-versus-host disease].

OBJECTIVE: Acute graft-versus-host disease (aGVHD) is one of the major complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Prediction of human aGVHD may be of help in its diagnosis and therapy. METHODS: 22 patients undergoing HSCT were included in this study. After transplantation, serum concentrations of interleukin-6, interleukin-8, tumor necrosis factor-alpha, interferon-gamma and sIL-2R were measured periodically by using enzyme-linked immunosorbent assay. Immune reconstitution of CD(+)(3), CD(+)(4), CD(+)(8), CD(+)(25) and CD(+)(69) cells were analyzed with flow cytometry. RESULTS: All the patients achieved engraftment. 6 patients developed grade I GVHD and 4 patients developed grade III-IV GVHD. Patients with aGVHD demonstrated significantly higher sIL-2R levels than those without. The peak levels of grade III-IV GVHD were (420.3 +/- 59.8) U/L,and the peak levels of grade I GVHD were (221.5 +/- 38.8) U/L. The increase of sIL-2R level in serum preceded the clinical signs of aGVHD. The maximum levels of sIL-2R correlated significantly with the severity of aGVHD. The increase of CD(+)(25) cells was in accordance with that of sIL-2R. CONCLUSIONS: Analysis of serum cytokines and immune reconstitution after HSCT may provide predictive value for aGVHD.

Adolescent↗

[The application of laser therapy plus endobronchial stenting in treatment of complete airway obstruction].

OBJECTIVE: To assess the efficacy of laser therapy plus endobronchial stenting in the treatment of complete airway obstruction. METHODS: 17 cases with complete airway obstruction were treated with Nd: YAG laser and endobronchial stenting from April 1998 to November 2000. The patients' dyspnea, airway gauge, pulmonary function and complications were observed. RESULTS: The airways were all restructured following a single or multiple laser treatment; the airway gauge enlarged and the average diameter increased (5.82 +/- 1.01) mm. Immediate relief of dyspnea was achieved in sixteen patients and dyspnea index lessened one grade in 4 patients, 2 grades in 11 and 3 grades in one. Obvious improvement of forced expiratory volume in one second (FEV(1)) was noted in all patients;the improvement averaged (0.49 +/- 0.18) L. Endobronchial stents were placed for 14 patients after laser treatment. After stent placement, the airway was further opened and the average airway gauge increased (3.50 +/- 0.94) mm further in diameter. Patients' dyspnea and FEV(1) were further improved; dyspnea index lowered one grade in eight patients and 2 grades in two patients. FEV(1) improved further (0.41 +/- 0.20) L in average. Complications after laser therapy included hypoxemia in 15 patients, hemorrhage in 2 and postoperative dyspnea in 3. Follow-up duration ranged from 2-20 months. Complications after stenting included recurrent pneumonia in 4 patients, airway obstruction due to granuloma or tumour growth in 5 and stent migration in 1. CONCLUSION: Laser therapy and endobronchial stent placement were effective in the treatment of patients with totally occluded airway. Nd: YAG laser can be first chosen to restructure the occluded airway, then endobronchial stent must be used to further enlarge the airway and maintain the therapeutic effect.

Adolescent↗

[Modulation of human small cell lung cancer cell line GLC4/ADR multidrug resistance in the inhibition of multidrug resistance-associated protein and its antisense].

OBJECTIVE: To study the effect of antisense multidrug resistance-associated protein (MRP) RNA on multidrug resistance (MDR) in the human small cell lung cancer (SCLC) cell line GLC4/ADR, in which the overexpression of MRP gene is discovered. METHODS: In using the plasmid pRC/RSV-MRP1 containing complete ORF of MRP as a template, two antisense recombinants targeting at the 5' and 3' regions were constructed with the application of the polymerase chain reaction (PCR) technique. Lipofectamine was conducted to transduce these antisense MRPs into the GLC4/ADR cells. Three clones (the GLC4/ADR-pcDNA3, MO; GLC4/ADR-MRP-5' region, Ma; GLC4/ADR-MRP-3' region, Mb) of transfectants after the selection of G418 were obtained. The expression of MRP protein was detected by the use of the Western blot and the MTT method for determination of chemosensitivity to ADR was used. RESULTS: The antisense MRPs was found to be effectively expressed in the clones, being transfected with two different antisense MRPs. The MRP expression in these transfectants were inhibited at the rates of 14.0% (GLC4/ADR Ma) and 83.0% (GLC4/ADR Mb), respectively. Moreover, decrease in the ADR resistance was observed in the Ma and Mb at the rates of 9.5% and 28.4%. Although the intracellular ADR concentration was increased in these transfectants, the proliferation and cell cycle and their early apoptosis induced by the ADR, indicated no difference between the transfectants and parental cells. CONCLUSION: It is possible to obtain the effective expression of the MRP antisense structures for the blocking of the mRNA translation in GLC4/ADR cell line and the fragment complementary to the 3'-region of MRP is more effective for the inhibition of the MRP than that related to the 5'-region of MRP. The antisense RNA may be a useful treatment in combination with the conventional chemotherapy for SCLC, in which the MRP overexpression usually occurs.

ATP Binding Cassette Transporter, Subfamily B↗

[Changes in aldosterone binding activity of kidney cytosol after stress in rats and the regulation].

To observe the changes in aldosterone binding activity of kidney cytosols after pathological stress in rats and the regulation, binding capacity (Rt) and apparent dissociation constant (Kd) of aldosterone binding activity of kidney cytosols in normal, low-degree or heavy-degree scalded rats were measured by radioligand binding assay using [3H]aldosterone as the ligand. Changes in Rt and Kd of aldosterone binding activity were observed after injection of anti-rat TNF alpha and IL-1 beta antibodies, alpha-melanocyte-stimulating hormone (alpha-MSH) and KPV peptide (Ac-D-Lys-L-Pro-D-Val). The results indicated that there were two types of aldosterone binding activities in kidney cytosol with different Rt and Kd, and the Rt of heavy-degree scalded rats (Rt1: 22.4 +/- 5.4 fmol/mg pro, Rt2: 196.3 +/- 32.5 fmol/mg pro) was lower than that of the control group (Rt1: 41.6 +/- 7.2 fmol/mg pro, Rt2: 317.6 +/- 70.0 fmol/mg pro) (P < 0.01; P < 0.01); while the Rt of low-degree scalded rats (Rt1: 41.4 +/- 5.0 fmol/mg pro, Rt2: 314.8 +/- 45.7 fmol/mg pro) was not significantly different from that of the control group (P > 0.05; P > 0.05). Injection of anti-rat TNF alpha and IL-1 beta antibodies, alpha-MSH and KPV prevented Rt of aldosterone binding activity from decrease in kidney cytosol of rats with heavy-degree scald. These findings suggest that aldosterone binding activity may be down-regulated in heavy-degree scalded rats, but it may be reversed by injection of anti-rat TNF alpha and IL-1 beta antibodies, alpha-MSH and KPV.

Aldosterone↗