Biomedical subjects

Y Qin

Publications and source records attributed to Y Qin.

At least 73 records · Page 4Linked to original sources

PubMed1999

TRFK-5 reverses established airway eosinophilia but not established hyperresponsiveness in a murine model of chronic asthma.

We studied the effects of an anti-interleukin (IL)-5 monoclonal antibody (TRFK-5) or dexamethasone (DEX) to reverse already established airway hyperresponsiveness (AHR) and tissue eosinophilia in a Schistosoma mansoni antigen-sensitized and airway-challenged mouse model of chronic asthma. In this model at 4 d after antigen challenge there is dramatic bronchoalveolar lavage fluid (BAL) eosinophilia, AHR to intravenous methacholine (MCh), and histologic evidence of peribronchial eosinophilic infiltration and mucoid cell hyperplasia. These changes persist for up to 2 wk after antigen challenge. Treatment with DEX from Days 4 through 10 significantly reduced established airway eosinophilia compared with animals sham-treated with saline from Days 4 -10 (120 +/- 29 eosinophils/microl BAL for DEX-treated mice versus 382 +/- 60 eosinophils/microl BAL for sham-treated animals, p < 0.01). DEX-treated mice also had dramatically reduced mucoid cell hyperplasia, and airway responsiveness returned to normal. In contrast, TRFK-5 given during the same time period reduced airway eosinophilia (86 +/- 32 eosinophils/microl BAL versus 382 +/- 60 eosinophils/microl BAL, p < 0.01) but did not reduce goblet cell hyperplasia or reverse already established AHR. Treatment with DEX but not TRFK-5 also inhibited interferon gamma (IFN-gamma) content of BAL fluid (0.49 +/- 0.09 ng/ml BAL fluid for DEX versus 1.50 +/- 0.24 ng/ml BAL fluid and 1.36 +/- 0.13 ng/ml BAL fluid for TRFK-5 and sham-treated mice, respectively, both p < 0.001 versus DEX). Thus, treatment with DEX reduces established eosinophilic airway inflammation and AHR in S. mansoni-sensitized and airway-challenged mice but treatment with TRFK-5 reversed established eosinophilia without ameliorating established AHR. Together, these data suggest that once airway inflammation develops, neutralizing the effects of IL-5 or reducing eosinophilia alone may not result in inhibiting established AHR in atopic asthma.

Allergens↗

PubMed1999

CD28 interactions with either CD80 or CD86 are sufficient to induce allergic airway inflammation in mice.

Previous studies have shown that the pan CD28/cytotoxic T lymphocyte antigen (CTL)A-4 antagonist CTLA4 immunoglobulin (Ig) inhibits eosinophilic airway inflammation in Schistosoma mansoni-sensitized and airway-challenged mice. In the present study, the importance of CD28 as well as the individual roles of CD80 and CD86 were examined in this system using wild-type and CD28 knockout (KO) mice. Unlike wild-type controls, CD28KO mice did not produce systemic IgE or eosinophilic airway inflammation after antigen challenge. However, a lymphocytic infiltrate and continued production of interferon-gamma was observed in these animals. Thus, CD28 is not essential for the initial recruitment of lymphocytes into antigen-challenged airways but critically regulates the allergic T-helper 2 phenotype. We next determined by polymerase chain reaction and flow cytometry that CD80 and CD86 molecules are constitutively expressed in the naive murine lung and on eosinophils in the allergic lung, suggesting a potential important role for both ligands in the development of asthma. Combined anti-CD80/anti-CD86 treatment throughout the antigen challenge period fully blocked the development of allergic airways, whereas a partial reduction was observed in mice treated with either anti-CD80 or anti-CD86 antibody alone. However, only anti-CD86 blocked systemic IgE production. Therefore, signaling through either CD80 or CD86 is sufficient to generate a partial local allergic response, whereas CD86 costimulation is essential to induce systemic allergic (IgE) reactions. Finally, combined anti-B7 monoclonal antibody treatment after sensitization reduced airway eosinophilia and interleukin (IL)-4/IL-5 cytokine secretion consistent with an ongoing role for CD28/B7 interactions in the effector phase of the disease. These results emphasize the importance of differential B7 expression on different cells and in different organs on subsequent CD28/B7-mediated immune events, including the potential for CD28/B7 blockade in the treatment of atopic airway disease in people.

Animals↗

PubMed1999

[Construction of nested set of unidirectional deletion of recombinant plasmid DNA for sequencing].

In order to rapidly sequence a batch of large DNA fragments, we developed a method for the construction of nested set of unidirectional deletions. A nested set of unidirectional deletions of the large DNA fragment of a c-type retrovirus gene was successfully constructed by the adoption of this method. The recombinant plasmid DNA was excised by BamHI and SphI at on end of the target DNA to create 5' and 3' overhanging ends. The DNA was digested with Exo III from 5' overhanging end to generate a set of unidirectional deletion. With the use of this method a set of deleted plasmid DNA and the deleted target DNA excised from the deleted constructs were observed on agrose gel electrophoresis. We sequenced all of 24 deleted DNA fragments (forward and reverse orientation). All of them contained overlapping sequences at their ends. These sequences were readily aligned. The results demonstrate this is an efficient method for sequencing large DNA fragment. The influential factors in this method were discussed in this report.

DNA, Recombinant↗

PubMed1999

[Determination of 6-methoxy-2-naphthylacetic acid, a major metabolite of nabumetone, in human plasma by HPLC].

This paper reports a sensitive and rapid method for determining 6-methoxy-2-naphthylacetic acid (MNA), a major metabolite of nabumetone in human plasma using naproxen as the internal standard. High performance liquid chromatograph model 680 (Waters, USA) with a variable wavelength UV detector and reversed-phase YWG-C18 column (10 microns, 250 x 4.6 mm) was used. After the addition of acetate buffer(pH3.0), the plasma sample was extracted with methylene chloride. The mobile phase of methanol-pH3.0, 0.02 mol/L acetate buffer(74:26) was pumped at 1.0 ml/min through the column. The detector at 0.01AUFS was set at 270 nm. The retention times for MNA and naproxen were 3.98 min and 4.73 min respectively. Standard curve was linear in the concentration range of 0.5 to 64 mg/L. The detection limit in serum was 0.02 mg/L. Extraction recovery was 88%-94%; method recovery 96%-102%; withinday RSD less than 3.5%; inter-day RSD less than 5%.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1999

[Simultaneous determination of norepinephrine and epinephrime in plasma by using high performance liquid chromatograph].

A sensitive and rapid method was reported for the determination of nerepinephrine (NE) and epinephrine (E) in plasma by using high-performance liquid chromatography with an electrochemical detector (HPLC-EC) and YWG-C18 column(5u). 3,4-Dihydroxybenzylamine(DHBA) was used as an internal standard. The mobile phase of 0.05 mol/L actate buffer(pH3.0)-methanol-0.05 mol/L EDTA-Na2(78:20:2) with of 200 mg/L SDS solution was pumped through the column with a flow rate of 1.0 ml/min. The lengths of retention time for NE, E and DHBA(IS) was 7.3 min, 8.3 min and 10.4 min, respectively. The standard curve was linear within the concentration range of 31.25 to 4000 ng/L for NE and E (NE: r = 0.9999 E: r = 0.9996). The within day RSD (%) were less than 1.87% for NE and less than 2.07% for E, inter-day RSD(%) were less than 8.92% for NE and less than 9.65% for E respectively. The average extraction recovery(%) for NE and E were 93.5% +/- 5.50% and 91.3% +/- 1.77% respectively. This method has been applied to the diagnosis of pheochromocytoma and clinical research.

Adrenal Gland Neoplasms↗

PubMed1999

[Effect of composite salviae dropping pill on endothelin gene expression in circulating endothelial cells of patients with coronary heart disease].

OBJECTIVE: To explore the effect of composite salviae dropping pill (CSDP) on endothelin (ET-1) gene expression in circulating endothelial cells. METHODS: Seventy cases of stable angina pectoris were randomly divided into 2 groups, the CSDP group and the isosorbide dinitrate (ID) group. They were treated with CSDP and ID respectively, their ET-1 gene expression in endothelial cells of peripheral circulation was measured before and after treatment by reverse transcriptase-Polymerase Chain Reaction and compared between the two groups as well as with that of 30 healthy subjects. RESULTS: Electrophoresis banding of 546 bp cDNA procured from 69 cases of 70 patients was positive, while no positive banding was obtained from healthy subjects. Six cases from the 29 patients treated with CSDP had their banding turned to negative, while in the ID group, no one had turned to negative after treatment. And ET-1 PCR product (absorbed optic density) in the CSDP group was markedly lower than that in the ID group, P < 0.05. CONCLUSION: DSP could inhibit ET-1 gene expression in endothelial cells of peripheral circulation directly.

Aged↗

PubMed1999

[CT scanning analysis for maxillary sinus bony septum abnormalities and its clinical significance].

OBJECTIVE: To assess the extent and distribution of disease as well as associated anatomic abnormalities in patients with chronic sinusitis and nasal polyps. METHOD: Both axial and coronal CT scans of eight patients who failed medical therapy and functional endoscopic sinus surgery (FESS) were reviewed retrospectively. RESULT: Among them, five were found to have vertically aligned coronal bony septum, two were horizontal, one sagittal. Complete bony septum divided the maxillary sinus into two separate cavities in four patients, others had incomplete bony septum. Based upon the CT scan findings, patients suffered from these anatomic abnormalities received Galdwell-Luc procedures and pansinusectomy through mid-facial degloving approach respectively. All patients did well postoperatively and were symptom free for six months. CONCLUSION: The results showed that the CT scan can display the distribution and extent of residual disease, demonstrate anatomic abnormalities, and guide therapeutic intervention. The combination of axial with coronal CT scan can effectively determine the incidence of the maxillary sinus bony septum.

Adolescent↗

PubMed1999

[Study on the catalytic spectrophotometric determination of trace manganese].

A new catalytic spectrophotometric method for determining trace amounts of manganese has been developed. The method is based on catalytic oxidation of morin by hydrogen peroxide. Manganese has catalytic effect. The detection limit for manganese is 0.004 microg/mL. The linear range of the determination is 5-80 ng/mL of manganese. The method has been used to determine trace manganese in wine.

Catalysis↗

PubMed1998

[Study on toxicity of P-Dichlorobenzene].

The authors studied the toxicity of P-Dichlorobenzene(P-DCB). The results showed that the toxicity of P-DCB was low. It has no accumulation (K > 5), no eye irritation and no skin sensitization effects. But light skin irritation effect was observed. In sub-acute inhalate exposure, damage on the function of liver and kidney was not observed. Genotoxic tests showed that tests in s. typhimurium strains TA98 and TA100 did not show any mutagenic potential. In Chinese hamster lung fibroblast CHL cell test system, it did not cause chromosomal aberrations.

Animals↗

PubMed1998

Clonal expansion and somatic hypermutation of V(H) genes of B cells from cerebrospinal fluid in multiple sclerosis.

The cerebrospinal fluid (CSF) of multiple sclerosis (MS) patients is characterized by increased concentrations of immunoglobulin (Ig), which on electrophoretic analysis shows restricted heterogeneity (oligoclonal bands). CSF Ig is composed of both serum and intrathecally produced components. To examine the properties of intrathecal antibody-producing B cells, we analyzed Ig heavy-chain variable (V(H)) region genes of B cells recovered from the CSF of 12 MS patients and 15 patients with other neurological diseases (OND). Using a PCR technique, we could detect rearrangements of Ig V(H) genes in all samples. Sequence analysis of complementarity-determining region 3 (CDR3) of rearranged VDJ genes revealed expansion of a dominant clone or clones in 10 of the 12 MS patients. B cell clonal expansion was identified in 3 of 15 OND. The nucleotide sequences of V(H) genes from clonally expanded CSF B cells in MS patients demonstrated the preferential usage of the V(H) IV family. There were numerous somatic mutations, mainly in the CDRs, with a high replacement-to-silent ratio; the mutations were distributed in a way suggesting that these B cells had been positively selected through their antigen receptor. Our results demonstrate that in MS CSF, there is a high frequency of clonally expanded B cells that have properties of postgerminal center memory or antibody-forming lymphocytes.

Adolescent↗

PubMed1998

Expression and cytogenetic localization of the human SM22 gene (TAGLN).

SM22 is a 22-kDa protein identified variously as SM22, transgelin, WS3-10, or mouse p27. Though its precise function is unknown, it is abundant in smooth muscle and so may contribute to the physiology of this widespread tissue. We found that cosmid 16b6 contains the entire 5.4-kb, five-exon human SM22 gene (HGMW-approved symbol, TAGLN), and we cytogenetically localized the gene to chromosome 11q23.2. Northern analysis of human adult tissues showed that SM22 mRNA is most prevalent in smooth muscle-containing tissues, but is also found at lower levels in heart. The human SM22 promoter contains nuclear factor-binding motifs known to regulate transcription in smooth muscle, and human SM22 promoter-luciferase reporter constructs exhibited high transcriptional activity in A7r5 or primary canine aortic smooth muscle cells, but show little activity in nonmuscle COS7 cells. In addition, human SM22 promoter activity increased by two- to threefold upon serum stimulation of nonmuscle cells.

Adult↗

PubMed1998

Characterization of a C-type retrovirus isolated from an HIV infected cell line: complete nucleotide sequence.

As previously reported, a C-type retrovirus, referred to as retrovirus X was isolated from HIV infected cells. In order to further characterize this virus, the proviral DNA was cloned and sequenced. The organization of the genome (8379 bp) appeared to be typical of the mammalian type C retroviruses. The virus was shown to be closely related to the gibbon ape leukaemia virus (GALV) with 87% similarity when the sequence was compared with the published genome of the Seato strain of GALV. At the level of the long terminal repeat where comparison was possible with other strains, the closest relationship was found with the San Francisco strain of GALV and with the simian sarcoma virus. These results suggest that the isolate should be considered as a strain of GALV.

Amino Acid Sequence↗

PubMed1998

CD40 ligand and autoantigen are involved in the pathogenesis of low-grade B-cell lymphomas of mucosa-associated lymphoid tissue.

Low-grade MALT-type lymphomas are malignancies of mucosal marginal-zone B cells and preceded by reactive inflammatory lymphoid tissue. Experimental observations suggest that antigen and CD40 Ligand act during cognate T/B cell interaction and are crucial for germinal center B-cell maturation generating marginal-zone B cells. To investigate the mechanisms underlying the development of extranodal MALT-type lymphomas, the immunoglobulin receptor was sequenced and analyzed for antigen specificity using heterohybridoma technology. Furthermore, CD40 ligand expression was evaluated by immunohistochemistry and by semiquantitative RT-PCR, and ligand binding to the CD40 of tumor B cells was studied using the CD40 system. Hypermutations were found in low-grade lymphomas throughout CDR1-CDR3 suggestive of positive selection through their antigen receptor. Different VH families were used and more than 69% of tumor immunoglobulins bound different mucosal antigens. CD40L expression was found in the tumor marginal zone in substantial amounts. The in vitro proliferation response of all low-grade MALT-type lymphomas was dependent on anti-CD40-mediated signals and cytokines. Our data provide evidence that autoantigen as well as the CD40L expressed by activated nonneoplastic T cells may drive the evolution of low-grade MALT-type lymphomas either directly or by paracrine mechanisms and that antigen may contribute to lymphoma pathogenesis.

Animals↗

PubMed1998

CTLA4Ig inhibits airway eosinophilia and hyperresponsiveness by regulating the development of Th1/Th2 subsets in a murine model of asthma.

Complete T-cell activation requires two distinct signals, one delivered via the T-cell receptor, and the second "co-stimulatory" signal through CD28/B7 ligation. Previous studies showed that the blockade of CD28/B7 ligation alters differentiation of Th1/Th2 lymphocyte subsets in vitro and in vivo. The present study was designed to determine the effect of a CD28/B7 antagonist (CTLA4Ig) on Th1/Th2 development in Schistosoma mansoni-sensitized and airway-challenged mice. Treatment of mice with CTLA4Ig beginning 1 wk after sensitization abolished airway responsiveness to intravenous methacholine determined 96 h following antigen challenge. We also found a significant reduction in bronchoalveolar lavage (BAL) eosinophilia, and reduced peribronchial eosinophilic infiltration and mucoid-cell hyperplasia. Furthermore, CTLA4Ig treatment significantly decreased interleukin (IL)-4 and IL-5 content in BAL fluid in vivo, and the production of IL-5 by lung lymphocytes stimulated with soluble egg antigen (SEA) in vitro. In contrast, the content of interferon-gamma in BAL fluid and supernatant from SEA-stimulated lung lymphocytes from CTLA4Ig-treated mice was increased significantly compared with untreated animals. Thus, CTLA4Ig inhibits eosinophilic airway inflammation and airway hyperresponsiveness in S. mansoni-sensitized and airway-challenged mice, most likely due to attenuated secretion of Th2-type cytokines and increased secretion of Th1-type cytokines.

Abatacept↗

PubMed1998

Atrial conduction curves in patients with and without atrial fibrillation.

In order to quantify underlying atrial conduction properties in patients with atrial fibrillation (AF) using clinical electrophysiology techniques, atrial conduction curves relating intra-atrial conduction times to extrastimulus prematurities during programmed atrial stimulation were drawn. Based on the presence or absence of AF episodes, 95 subjects were divided into 2 groups: control (n=42); and AF (n=53). During programmed stimulation introduced from the right atrial appendage, an atrial conduction curve was drawn for each patient. For most of the control subjects, when the extrastimulus prematurity was increased by 10-ms steps, the intra-atrial conduction times also increased gradually; the maximum stepwise prolongation in intra-atrial conduction time was 11.0+/-3.4 msec. For patients with AF, a 10-msec increase in extrastimulus prematurity often produced a sudden marked prolongation in the intra-atrial conduction time; the maximum stepwise prolongation of intra-atrial conduction time was 21.4+/-5.9 msec. In contrast to the gradual atrial conduction curves recorded in control subjects, the sudden prolongation of intra-atrial conduction time was remarkable on the curves obtained in patients with AF. Statistical significance was clearly established (p<0.0001). This difference could be related to differences in the underlying conduction properties in patients with and without AF.

Adult↗

PubMed1998

Chitin and chitosan fibres.

Chitin and chitosan are natural polymers extracted from various plants and animals. Recently, they have attracted much interest in the biomedical industry because of their biodegradability, biocompatibility and accelerated wound healing properties. This article reviews how chitin and chitosan fibres are produced and their potential.

Biocompatible Materials↗

PubMed1998

[Observation of cicatricial fibroblasts in culture and its biological properties].

In order to study the biological properties of fibroblasts isolated from different tissues. The fibroblasts from normal skin, hypertrophic scar and keloid were cultured, respectively, in vitro, and their morphologies and growth kinetics were compared. The results revealed that although fibroblasts in keloid were irregularly arranged, crisscross and overlapping with loss of polarization, there was no significant difference in the 3 groups so far the cellular morphology of fibroblast itself, cellular growth curve, cellular mitotic index, cloning efficiency and DNA content provided those cultures were in the same cellular density and culture conditions. It was concluded that fibroblasts isolated from culture of normal skin, hypertrophic scar and keloid in vitro showed no significant difference in morphology and growth kinetics, on the contrary, their biological behaviors were quite similar.

Adolescent↗

PubMed1998

[The effect of partial hepatectomy and portal vein occlusion on aminopyrine metabolism capacity of the liver in rats].

To observe the variation of metabolic function and anatomical weight of the liver after partial hepatectomy and occlusion of portal branches feeding the same magnitude of the liver lobes, hepatic 14C-aminopyrine demethylation capacity determined by aminopyrine breath test and liver weight in rats were examined and compared in series in this study. The results showed that 14CO2 expiratory clearance rate was reduced by 50% at 2 hours and by 70% at 24 hours after 70% hepatectomy. Then it increased gradually and was similar to the preoperative level in 2 weeks. The remnant liver weight was lowest at 2 hours and increased to 80% of the control in 7 days after 70% hepatectomy. It recovered to normal in 2 weeks. In 90% hepatectomy group, 14CO2 expiratory clearance rate decreased by 90% at 2 hours after operation. Thereafter, all rats died very soon. In the 2 portal vein occlusion groups, 14CO2 expiratory clearance rate had little change at 2 hours and it declined by about 40% at 24 hours after ligation of portal branches feeding 70% or 90% liver mass. It recovered gradually and returned to the preoperative level in 2 weeks. The total liver weight in 2 portal occlusion groups was not significantly different from that in the control except that it was slightly lower than the control at 24 hours after operation. This experimental study suggests that comparing deprivation of portal blood feeding partial liver mass with corresponding partial hepatectomy, the former can not only keep the anatomical liver weight relatively stable but also produce a lesser damage to hepatic metabolic function.

Aminopyrine↗