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Biomedical subjects

Q Xue

Publications and source records attributed to Q Xue.

At least 37 records · Page 2Linked to original sources
PubMed2001

Clinicopathologic study of mucosa-associated lymphoid tissue lymphoma of the salivary gland.

OBJECTIVE: To study the histopathologic features and pathogenesis of mucosa-associated lymphoid tissue lymphoma (MALT-oma) of salivary glands. METHODS: Clinical data, paraffin-embedded sections, immunohistochemical slides (SP method) and electron microscopic features of surgical specimens of 32 cases of salivary gland MALT-oma were studied. RESULTS: The patients were 27 males and 5 females, with a mean age of 54.76 years. The lesions were located in the parotid area in 17 cases, and in the submandibular gland in the remaining 15 cases. Much of the MALT-oma was replaced by infiltration of a great amount of centrocyte-like cells (CCL) as background and occasional large cells (centroblast- or immunoblast-like). In MALT-omas "lymphoepithelial lesions" were present. Immunohistochemically, CD20 expression was found to be positive and CD45RO expression was negative in all MALT-omas. CONCLUSION: Most of the MALT-omas are low grade malignant tumors and have a "homing back" phenomenon. The cases were managed by surgery and chemotherapy. In a few MALT-omas which turned into high grade malignant tumors, the prognosis was poor. Acquired MALT may develop as a reaction to autoimmune disease and infection. Hyper-immune reaction and MALT hyperplasia under stimulation may result in myoepithelial sialadenitis and lead to MALT-oma of the salivary gland.

Adolescent↗
PubMed2001

Role of beta-adrenoceptor at different stages of bronchial asthma.

OBJECTIVE: To investigate the changes of beta-adrenergic receptor (beta AR) in peripheral lymphocytes and beta 2AR mRNA levels at different stages of bronchial asthma. METHODS: beta 2AR density and beta 2AR mRNA level in peripheral lymphocytes, cAMP and cGMP levels in blood plasma were estimated by radioligand binding assay, radioimmunoassay and RT-PCR. RESULTS: (1) Maximum bound volume (Bmax) and equilibrium dissociation constant (Kd) of beta 2AR of lymphocyte in asthma patients at remission stage were markedly higher than that in normal subjects, while cAMP levels in blood plasma showed no difference. Bmax of beta 2AR and cAMP levels in asthma patients at acute exacerbation stage were significantly lower than that in normal subjects, and Kds between these two groups were not much different. (2) Expression of beta 2ARmRNA in peripheral lymphocytes of asthmatics at remission stage was not significantly different compared with that in normals. CONCLUSIONS: Amount and function of beta AR and beta 2ARmRNA levels are related to asthmatic conditions. Changes of beta AR and beta 2ARmRNA in asthma might rather be a pathological change accompanied by the course of the disease than a primary defect.

Adult↗
PubMed2001

[The study of TNF-alpha destructive action to the bone in human middle cholesteatoma].

OBJECTIVE: To study the expression of TNF-alpha in the cholesteatoma and elucidate the role of TNF-alpha in the destruction of bone. METHOD: All samples (5 microns paraffin sections) from 25 cholesteatoma cases and 10 normal cases were examined by immunohistochemical SABC method and analysed by computer image. RESULT: In 25 cholesteatoma cases, TNF-alpha expressed in the cytoplasm of the full epithelial tissue cells, subcutaneous inflammatory cells and fibroblast. In contrast, the normal cases, there were 6 cases week positive, 4 cases negative. The results of the computer image quantitative analysis system showed that the mean optical density of TNF-alpha was 0.1326 +/- 0.0022 in the cholesteatoma epithelial tissue and 0.0868 +/- 0.0014 in normal skin epithelial tissue respectively, both of which had significantly differentiation (P < 0.05). CONCLUSION: TNF-alpha may be a factor of the destruction of bone of cholesteatoma.

Adolescent↗
PubMed2001

[Study on the photoluminescence spectrum of nickel passivation treatment of porous silicon].

A new method for electrolysis passivation treatment of porous silicom (PS) in NiCl2 is reported in this paper. The photoluminescence (PL) spectra of PS treated in different time is observed, the spectra show that peak intensity is 2.5 times stronger than that without treatment, peak wavelength is 33 nm blue shift when PS is treated properly. The phenomenon caused is that the results of the SiHx change into SiNix when replaced H by Ni on surface of PS.

Chemical Phenomena↗
PubMed2000

Development of multichannel devices with an array of electrospray tips for high-throughput mass spectrometry.

The basic principles of multichannel devices with an array of electrospray tips for high-throughput infusion electrospray ionization mass spectrometry (ESI-MS) have been developed. The prototype plastic devices were fabricated by casting from a solvent-resistant resin. The sample wells on the device were arranged in the format of the standard 96-microtiter well plate, with each sample well connected to an independent electrospray exit port via a microchannel with imbedded electrode. A second plastic plate with distribution microchannels was employed as a cover plate and pressure distributor. Nitrogen gas was used to pressurize individual wells for transport of sample into the electrospray exit port. The design of independent microchannels and electrospray exit ports allowed very high throughput and duty cycle, as well as elimination of any potential sample carryover. The device was placed on a computer-controlled translation stage for precise positioning of the electrospray exit ports in front of the mass spectrometer sampling orifice. High-throughput ESI-MS was demonstrated by analyzing 96 peptide samples in 480 s, corresponding to a potential throughput of 720 samples/h. As a model application, the device was used for the MS determination of inhibition constants of several inhibitors of HIV-1 protease.

Angiotensins↗
PubMed2000

Separation of European flat oyster, Ostrea edulis, haemocytes by density gradient centrifugation and SDS-PAGE characterisation of separated haemocyte sub-populations.

A two-step gradient centrifugation with Percoll and Ficoll successively as density medium was developed to separate European flat oyster, Ostrea edulis, haemocytes into three sub-populations representing granulocytes, large hyalinocytes and small hyalinocytes, respectively. After a Percoll gradient centrifugation, granulocytes and agranulocytes were separated and a pure fraction of granulocytes was obtained. The agranulocytes were further separated by centrifugation through a Ficoll gradient, and two haemocyte subpopulations representing large hyalinocytes and small hyalinocytes were obtained. No significant impact on the haemocyte viability was detected after separation with this two-step density gradient centrifugation. The three haemocyte sub-populations showed different protein patterns in SDS-PAGE.

Animals↗
PubMed2000

Enzymatic activities in European flat oyster, Ostrea edulis, and pacific oyster, Crassostrea gigas, hemolymph.

Enzymatic activities in the hemolymph of healthy and Bonamia-infected Ostrea edulis and Crassostrea gigas were studied with a commercial kit for the detection of 19 enzymes: 15 and 16 enzymes, respectively, were detected in the hemolymph of O. edulis and C. gigas and 10 of them showed relatively high activity levels. Most of them existed in both the cell-free fraction of the hemolymph and in the hemocytes. The cell-free hemolymph fraction of Bonamia ostreae-infected European flat oysters showed an elevated enzymatic activity level compared with that of healthy individuals. C. gigas hemocytes possessed higher enzymatic activity levels than O. edulis hemocytes. Differences in enzymatic activities existed in granulocytes and hyalinocytes in both oyster species. The enzyme release from oyster hemocytes seemed to be selective. The infection by B. ostreae induced enzymatic activity variations in European flat oysters. Higher enzyme levels within hemocytes may contribute partly to the natural resistance of C. gigas to the infection by B. ostreae.

Animals↗
PubMed2000

Invasion and metastasis of hepatocellular carcinoma in relation to urokinase-type plasminogen activator, its receptor and inhibitor.

This study was designed to investigate the relationship of urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), and plasminogen activator inhibitor type-1 (PAI-1) to invasion and metastasis of hepatocellular carcinoma (HCC). The expression of uPA, uPAR, and PAI-1 in HCC was determined by immunohistochemistry, Northern blot, and an LCI-D20 nude mouse metastatic model of HCC. The overexpression of uPA, uPAR, and PAI-1 was found in HCC, especially in the patients with portal cancer embolus, tumor invasion, and metastasis. Immunohistochemistry results showed that the rate of positive staining of uPA, uPAR, and PAI-1 were higher in HCC than those in the control groups consisting of cancer-adjacent tissue and normal liver tissue. In the case of HCC invasion, positive uPA and uPAR were seen in 16 and 19 out of 22 patients, respectively (P<0.01 and P<0.001, respectively, as compared with the patients without invasion). In those with portal cancer embolus and tumor metastasis, positive uPAR was eight out of eight and six out of six patients. In those with tumor recurrence, positive uPAR was 15 out of 17 patients (P<0.01 vs. no recurrence). In patients who died within 2 years after surgery, positive uPAR was 12 out of 12 patients (P<0.01 vs. survival), and positive PAI-1 was nine out of 12 patients (P<0.05 vs. survival). In those in which uPA, uPAR, and PAI-1 were all positive staining, stronger cancer invasiveness and higher mortality were found (P<0.05 vs. patients with all negative staining). In 30 patients tested with Northern blot analysis, the results were similar to those tested with immunohistochemistry. Higher expression of uPA mRNA and PAI-1 mRNA were detected in tumor tissues and embolus. In the patients with positive signals of uPA mRNA and PAI-1 mRNA, invasive cases were found in seven out of 19 and eight out of 18 patients, respectively, which were significantly higher than those showing negative signals (P<0.05). In the LCI-D20 nude mouse metastatic model of HCC (MMHCC), PAI-1 activity in plasma and tumor tissue increased with tumor growth, invasion, and metastasis. At an advanced stage of MMHCC, PAI-1 activity rose to 15.4+/-0.7 Au/ml in plasma and 0.8+/-0.3 Au/mg in tumor extracts, which was significantly higher than 6.2+/-1.8 Au/ml in plasma and 0.4+/-0.1 Au/mg in extracts at an early stage (P<0.05). PAI-1 activity related to the changes of serum AFP and tumor progress were r = 0.9544 and r = 0.9648, respectively (P<0.05). The data suggest that the expression of uPA, uPAR, and PAI-1 is increased in HCC, and related to the invasiveness, metastasis, and prognosis of HCC.

Animals↗
PubMed2000

Immunohistochemical inactivation of p14ARF concomitant with MDM2 overexpression inversely correlates with p53 overexpression in oral squamous cell carcinoma.

The CDKN2 gene encodes two structurally different proteins: a cyclin-dependent kinase inhibitor called p16, which regulates retinoblastoma protein (pRb)-dependent G1 arrest, and a cell cycle inhibitor designated p14ARF, which arrests cell growth in G1-S and also in G2-M. Whereas inactivation of p16 has been described as a frequent event in various cancers, including oral cancer, the current function of p14ARF is still poorly understood. A physical association between p14ARF and MDM2 blocks MDM2-induced p53 degradation, resulting in increased levels of p53, which in turn leads to cell cycle arrest. The present study immunohistochemically examined the expression of p16 and p14ARF together with pRb, MDM2 and p53 status in a series of oral cancers. The results showed that p14ARF was frequently absent in the oral cancers (15/37, 41%) as was p16 immunostaining. Concomitant immunopositivity for p14ARF and MDM2 overexpression was frequently observed in a subset of the cancers, whereas an inverse correlation between p14ARF and MDM2 expression and the diffuse staining of p53 was clearly detected. Moreover, the results showed that in most cases of oral cancer (35/37, 95%) at least one protein was altered, and lymph node metastasis was more frequent in the tumors with alterations in both the p16/pRb and p14ARF/p53 pathway (8/16, 50%) than in the tumors with one or no alteration of these two major pathways.

Adult↗
PubMed2000

High-dose and long-term therapy with interferon-alfa inhibits tumor growth and recurrence in nude mice bearing human hepatocellular carcinoma xenografts with high metastatic potential.

Postoperative recurrence of human hepatocellular carcinoma (HCC) is the major issue that must be addressed to further improve prognosis. This study was undertaken to investigate the effects of interferon-alfa-1b (IFN-alpha-1b) on recurrent tumor and metastasis after curative resection in nude mice bearing an HCC xenograft with high metastatic potential. Tumor tissues from LCI-D20, a metastatic model of HCC in nude mice, were orthotopically implanted in 105 nude mice. Eleven days later, 64 mice underwent curative resection of liver tumors. IFN-alpha at different doses was administered subcutaneously to mice with or without resection. In mice without resection, when comparison was made among control, IFN 7.5 x 10(6) U/kg/day, 1.5 x 10(7) U/kg/day for treated groups, and 3 x 10(7) U/kg/day; tumor volume was 8,475 mm(3) +/- 2,636 mm(3), 7,963 mm(3) +/- 3,214 mm(3), 769 mm(3) +/- 287 mm(3), and 13 mm(3) +/- 9 mm(3); incidence of lung metastasis being 100%, 80%, 40%, and 0%; life span was 45 +/- 4 days, 53 +/- 8 days, 81 +/- 6 days, and 105 +/- 24 days, respectively. In mice with curative resection, when comparison was made among control, IFN 5 x 10(5) U/kg/day, 1 x 10(6) U/kg/day, 4 x 10(6) U/kg/day, 7.5 x 10(6) U/kg/day, 1.5 x 10(7) U/kg/day, and 3 x 10(7) U/kg/day for treated groups; incidence of recurrent tumor was 100%, 100%, 87.5%, 100%, 87.5%, 62.5%, and 12.5%; lung metastasis being 100%, 75%, 87.5%, 50%, 62.5%, 0%, and 0%, respectively. IFN-alpha inhibited neovascularization induced by LCI-D20 tumor specimens implanted into the micropocket of nude mice corneas. In conclusion, high-dose and long-term therapy with IFN-alpha dose-dependently inhibits tumor growth and recurrence after resection of HCC. The effect of IFN-alpha may be attributed to antiangiogenesis in this experiment. These results provide potential clinical implication, particularly for the prevention of recurrence after curative resection of HCC.

Animals↗
PubMed2000

The added diagnostic value of automated QT-dispersion measurements and automated ST-segment deviations in the electrocardiographic diagnosis of acute cardiac ischemia.

The purpose of this study was to determine the added value of automated QT dispersion and ST-segment measurements to physician interpretation of 12-lead electrocardiograms (ECGs) in patients with chest pain. To date, poor reproducibility of manual measurements and lack of shown added value have limited the clinical use of QT dispersion. Twelve-lead ECGs (n = 1,161) from the Milwaukee Prehospital Chest Pain Database were independently classified by 2 physicians into 3 groups (acute myocardial infarction (AMI), acute cardiac ischemia (ACI), or nonischemic), and their consensus was obtained. QT-end and QT-peak dispersions were measured by a computerized system. The computer also identified ST-segment deviations. Sensitivity, specificity, and positive predictive values (PPVs) and negative predictive values (NPV) for AMI and ACI were evaluated independently and in combinations. For AMI, physicians' consensus classification was remarkably good (sensitivity, 48%, specificity, 99%). Independent classification by QT-end and QT-peak dispersions or ST deviations was not superior to the physicians' consensus. Optimal classification occurred by combining automated QT-end dispersion and ST deviations with physicians' consensus. This combination increased sensitivity for the diagnoses of AMI by 35% (65% vs 48%, P < .001) and ACI by 55% (62% vs 40%, P < .001) compared with physicians' consensus, while maintaining comparable specificity. This study supports a potential clinical role for automated QT dispersion when combined with other diagnostic methods for detecting AMI and ACI.

Adolescent↗
PubMed2000

Automated discrimination between atrial fibrillation and atrial flutter in the resting 12-lead electrocardiogram.

Computerized time-domain analysis of the QRST-subtracted 12-lead electrocardiogram (ECG) has been used successfully to determine several atrial activity patterns. These time-domain methods are particularly useful for low-frequency signals such as those originating at the sinus node. However, high frequency atrial fibrillation (AFIB) and atrial flutter (AFL) waves can be better estimated by using spectral methods. In this study, we investigated the use of spectral entropy (SE) and spectral peak detection to distinguish fibrillatory from flutter activity in the QRST-subtracted ECG. In a set of 4,172 cardiologist-overread ECGs, a computerized ECG analysis program (12SL MAC-Rhythm, GE-Marquette Medical Systems, Milwaukee, WI) detected 270 AFIB rhythms and 100 AFL rhythms. Compared to the cardiologist's reading, the AFIB versus AFL miss-classification error was 5.6%. The Fourier Transform was used to estimate the power spectral density of the QRST-subtracted ECG data. Individual lead spectra were then averaged and SE was computed for each of the ECGs originally called AFIB or AFL by the computer program. Additional criteria that included SE, spectral peak frequencies, and time-domain measures of atrial activity were then applied to discriminate between the 2 rhythms. Employing these criteria resulted in a decrease of miss-classification error to 2.5%.

Algorithms↗
PubMed2000

Differential host inflammatory responses to viable versus antibiotic-killed bacteria in experimental microbial sepsis.

Staphylococcus aureus killed during imipenem or ceftazidime chemotherapy in mice elicited an early release of tumor necrosis factor alpha (TNF-alpha) into the systemic circulation. This response was coincident in time with an increase in leukocyte-endothelium adhesive interactions in the microvasculature. Equivalent responses were not observed without the antibiotic treatment (imipenem or ceftazidime). Protective efficacy of the same antibiotic treatment was markedly diminished in D-galactosamine-treated mice compared to controls; e.g., it dropped from 2,000-fold to 70-fold with 4 mg of imipenem per kg given at the time of challenge. Nevertheless, protection was quantitatively restored upon concurrent administration of neutralizing anti-TNF-alpha antibody or 4 mg of dexamethasone per kg to these TNF-alpha-hypersensitive mice. Importantly, protection afforded by dexamethasone was not seen when the animals were challenged with viable organisms but without the concurrent administration of antibiotic. An early TNF-alpha response could also be demonstrated upon challenge with Escherichia coli, but in this instance, neither the timing nor the magnitude of that response was influenced by treatment with these antibiotics. We conclude from these studies that the inflammatory response to viable versus killed bacteria may differ markedly depending on the particular bacterium, host sensitivity to TNF-alpha, and possibly the Gram stain classification.

Animals↗
PubMed2000

Cloning, characterization and heterologous expression of a polyketide synthase and P-450 oxidase involved in the biosynthesis of the antibiotic oleandomycin.

The gene cluster encoding the deoxyoleandolide polyketide synthase (OlePKS) was isolated from the oleandomycin producing strain Streptomnyces antibioticus. Sequencing of the first two genes encoding OlePKS, together with the previously identified third gene revealed an overall genetic and protein architecture similar to that of the erythromycin gene cluster encoding the 6-deoxyerythronolide B synthase (DEBS) from Saccharopolyspora erythraea. When the entire OlePKS (10,487 amino acids) was expressed in the heterologous host Streptomyces lividans, it produced 8,8a-deoxyoleandolide, an aglycone precursor of oleandomycin. The role of the P-450 monooxygenase, OleP, in oleandomycin biosynthesis was also examined in vivo by co-expression with DEBS in S. lividans. The production of 8,8a-dihydroxy-6-deoxyerythronolide B and other derivatives indicates that OleP is involved in the epoxidation pathway of oleandomycin biosynthesis. Since there are currently no genetic systems available for manipulation of the natural oleandomycin producing strain, the heterologous expression system reported here provides a useful tool for studying this important macrolide antibiotic.

Anti-Bacterial Agents↗
PubMed2000

[Antitumor activities in vivo of interleukin-12 gene modified dendritic cells in murine models].

OBJECTIVE: To study the antitumor activities of the mIL-12 transfected and acid-eluted peptide sensitized dendritic cells (DC) in murine H22 liver cancer model. METHODS: The murine bone marrow derived DC were transfected with the recombinant adenovirus (Ad mIL-12) containing the mIL-12 gene and control virus AdBGFP. The peptides on the surface of the murine H22 cell line were eluted with mild acid buffer and then sensitized the transfected DC. The experimental animals were immunized with the differently disposed DC and the state of tumorgenesis and tumor growth was observed. RESULTS: The tumor growth and weight in the group immunized with mIL-12 transfected and acid-eluted peptide sensitized DC were significantly lower than those of control group (P<0.05). CONCLUSION: The mIL-12 transfected and acid-eluted peptide sensitized DC can induce obvious antitumor activities in the murine liver cancer models and may suggest new strategies for constructing new type of DC vaccine for liver cancer.

Animals↗
PubMed2000

[Effects of oxidized LDL, hypoxia, and 5-hydroxytryptamine on 5-HT2A receptor and intracellular free Ca2+ in cultured vascular smooth muscle cells].

OBJECTIVE: To investigate the mechanisms of this hyperreactivity, the effects of oxLDL, hypoxia, and 5-HT (the relative factors inducing arteriosclerosis) on 5-HT2A receptor, receptor gene expression and intracellular free Ca2+ were observed in cultured rat aortic smooth muscle cells (ASMC). METHODS: ASMC underwent 50 micrograms/ml oxLDL 8 hours, 2% hypoxia 24 and 48 hours, 10 mumol/L 5-HT 30 min. 5-HT2A receptor, 5-HT2A receptor mRNA and [Ca2+]i of ASMC were estimated by radiobinding assay, RT-PCR and Southern blot method, and confocal laser scanning mode separately. RESULTS: After oxLDL, hypoxia, 5-HT pretreatment, 5-HT2A receptor of ASMC showed significant up-regulation. Both 5-HT2A receptor mRNA expression and 5-HT-induced [Ca2+]i of ASMC increased markedly after oxLDL, hypoxia pretreatment. CONCLUSIONS: 5-HT2A receptor up-regulation and cell [Ca2+]i increase of ASMC induced by oxLDL, hypoxia, and 5-HT may play a role in vascular hyperreactivity induced by 5-HT in atherosclerosis arteries.

Animals↗
PubMed2000

[Infrared study on molecular structure and orientation in Langmuir-Blodgett films of chiral LCs M1].

The LB films of chiral LCs M1 were investigated by FTIR transmission and reflection absorption spectra. CaF2 and vacuum deposition gold plate were used as solid substrate. The LB films can be transferred onto the solid substrate successfully. The orientation of LB films was analysis by comparing the FTIR transmission and reflection absorbance spectroscopy. The aromatic cores part which including the C-O bond was almost perpendicular the substrate surface, the alkyl chain and C=O part has a certain angle titled onto the substrate.

English Abstract↗