Biomedical subjects

X Qin

Publications and source records attributed to X Qin.

At least 91 records · Page 5Linked to original sources

PubMed1998

PYY stimulates synthesis and secretion of intestinal apolipoprotein AIV without affecting mRNA expression.

We tested whether exogenous peptide YY (PYY) can stimulate synthesis and lymphatic secretion of intestinal apolipoprotein AIV (apo AIV). Rats with mesenteric lymph fistulas and right atrial cannulas were given continuous intravenous infusions of control vehicle or PYY at 25, 50, 75, 100, or 200 pmol . kg-1 . h-1. PYY (75-200 pmol . kg-1 . h-1) stimulated lymphatic apo AIV output from 1.5- to 3.5-fold higher than basal output. In separate experiments, PYY (100 pmol . kg-1 . h-1) produced a 60% increase in jejunal mucosal apo AIV synthesis but had no effect on mucosal apo AIV mRNA levels at doses up to 200 pmol . kg-1 . h-1. Finally, exogenous PYY infusion (100 pmol . kg-1 . h-1) produced a plasma PYY increment of 30 pM compared with an increment of 18.7 pM in response to ileal infusion of lipid. These results support the hypothesis that PYY may be an endocrine mediator of the effects of distal gut lipid on production and release of intestinal apo AIV, likely via a posttranscriptional mechanism of action.

Animals↗

PubMed1998

Apolipoprotein AIV: a potent endogenous inhibitor of lipid oxidation.

Overexpression of apolipoprotein (apo) AIV in transgenic mice confers significant protection against atherosclerosis in apoE knockout animals even in the presence of a more severe atherogenic lipid profile. Because lipoprotein oxidation has been recognized to be pivotal in development of atherosclerosis, the antioxidative activity of apoAIV was investigated. Fasting intestinal lymph was used to mimic conditions in the interstitial fluid, the potential site for lipoprotein oxidation in vivo. ApoAIV (10 micrograms/ml) significantly inhibited copper-mediated oxidation of lymph. This inhibitory effect was further evaluated using purified low-density lipoprotein. Addition of apoAIV (2.5 micrograms/ml) increased the time of 50% conjugated diene formation by 2.4-fold, whereas apoE or BSA did not show such a protection even at 20 micrograms/ml. Addition of apoAIV during the propagation phase also resulted in a dose-dependent inhibition. ApoAIV also protected macrophage-induced oxidation of fasting lymph. These results provide the first evidence that apoAIV is a potent endogenous antioxidant.

Animals↗

PubMed1998

[Studies on incidence of malignant tumor in workers exposed to dust in a mine in 30 years].

OBJECTIVE: To investigate incidence of malignant tumor in workers exposed to dust in a mine during the past 30 years. METHODS: A retrospective cohort study was conducted in 16,711 workers exposed to dust and 7,598 non-exposed workers. RESULTS: Incidence of lung cancer in exposed workers ranked the first place, whth an SMR of 2.648, as compared with that of non-exposed workers. Incidence of lung cancer in the dust-exposed workers with a longer duration of employment was significantly higher than in those with a shorter one. Incidence of lung cancer in exposed workers with a wetoperation mode was lower than that in those with dry-operation mode. CONCLUSION: Malignant tumor, especially lung cancer, occurred more frequently in the workers exposed to dust, which could be a potential risk factor contributing to carcinogenesis.

Adolescent↗

PubMed1998

[Application and analysis of biochemical indices for the evaluation of antisilicosis treatment. Study on anti-silicosis therapy and its evaluation research group].

The levels of serum Ceruloplasmin (Cp), Superoxide dismutase (SOD) and IgG of 296 silicosis patients treated by tetrandrine, polyvinylpridine-N-Oxide, hydroxypiperaquinoline phosphate and aluminium citrate were measured. Sera were collected before and after the 1st, 3rd and 6th therapy courses. 144 Silicosis patients without treatment were observed as controls. The levels of these three indices decreased by the end of treatment. The levels of SOD were fluctuated, which were increased after the 3rd course, but decreased after the 1st and 6th courses. The decrease of Cp, SOD and IgG consisted with the clinical effectiveness of the treatment, indicating that Cp, SOD and IgG were appropriate biochemical indicators for the evaluation of antisilicosis drugs. The quality control and the statistics standardization for data analysis are important.

Alkaloids↗

PubMed1998

[The relationship between LPS-induced apoptosis in hepatocyte, Kupffer cell and hepatocytic damage].

OBJECTIVE: To study the role of tumor necrosis factor (TNF alpha) in the mechanisms of liver injury and the relationship between LPS-induced apoptosis in hepatocyte (HC), kupffer cell (KC), and hepatic damage. METHODS: In vitro, kupffer cells (1 x 10/ml) were stimulated with different concentrations of endotoxin (1-10 micrograms/ml) for 1-24 hr; the kupffer cells, which had been cultured with endotoxin for 24 hr, were isolated to coculture with hepatocytes (1:1) for 1-24 hr. Two kinds of cells of apoptosis and the block effect of TNF alpha antibody were detected by cell death ELISA, and the supernatant was performed to determine the levels of alanine aminotransferase (ALT), lactate dehydrogenase (LDH) at different time points. RESULTS: Following stimulation with LPS, the number of positive apoptotic KC increased in a concentration and time (3 h-24 h) dependent manner. In contrast, coincubation of HC with LPS-stimulated KC resulted in a marked increase in positive apoptotic hepatocyte when LPS concentration was greater than 1 microgram/ml. TNF alpha antibody blocked apoptosis in both KC and HC. Only when the LPS concentration was higher than 1 microgram/ml and cultured for 6 hr, the release of liver enzymes (ALT, LDH), responsible for hepacyte damage, rose significantly, but the process was behind of apoptosis, and TNF alpha antibody couldn't block it. CONCLUSION: TNF alpha mediates LPS-induced apoptosis in KC and HC, and the apoptosis precedes cellular damage. Massive apoptosis of KC may lead to the decrease of clearance of LPS, thereby exacerbating septic shock, hepatocyte damage and apoptosis.

Apoptosis↗

PubMed1998

Lidocaine improving the cerebral protection by retrograde cerebral perfusion.

OBJECTIVE: To determine whether lidocaine can improve the cerebral protection provided by retrograde cerebral perfusion. METHODS: Sixteen mongrel dogs were placed on cardiopulmonary bypass and cooled to 20 degrees C. Retrograde cerebral perfusion was then carried out for 120 minutes, with the external jugular venous pressure kept at 3.33 kPa. Cardiopulmonary bypass was resumed, and the animals were rewarmed to 36 degrees C. The animals were divided into two groups. In the lidocaine group (n = 8), lidocaine was administrated continuously throughout the experiment. In the control group (n = 8), normal saline was given at the same rate. RESULTS: In both groups, cerebral tissue creatine phosphate and adenosine triphosphate concentrations and energy charge increased by the end of hypothermic cardiopulmonary bypass, decreased continuously during retrograde cerebral perfusion, and recovered gradually after resuming cardiopulmonary bypass. Nevertheless, they recovered to significantly higher levels in the lidocaine group than in the control group (creatine phosphate: 2.44 +/- 0.53 versus 1.61 +/- 0.49 mumol/g wet weight, P = 0.006; adenosine triphosphate: 0.71 +/- 0.18 versus 0.50 +/- 0.17 mumol/g wet weight, P = 0.029; energy charge: 0.59 +/- 0.10 versus 0.48 +/- 0.09, P = 0.044) by the end of the experiment. There was no significant difference between the two groups in the cerebral tissue water content (control group: 77.6% +/- 1.9%; lidocaine group: 77.6% +/- 1.3%). CONCLUSION: Continuous lidocaine infusion accelerates the recovery of cerebral tissue high energy phosphate contents after resuming cardiopulmonary bypass, but it has no effect on the formation of cerebral edema after retrograde cerebral perfusion.

Adenosine Diphosphate↗

PubMed1998

[Determination of sunscreen agents in cosmetic products by reversed-phase high performance liquid chromatography].

A method for quantitative determination of eleven sunscreen agents (benzophenone-4,p-amino-benzoic acid, salicylic acid, benzophenone-3,phenyl salicylate, 4-methylbenzylidene camphor, octyl dimethyl p-amino-benzoate, isopropyl dibenzoylmethane, butyl methoxydibenzoylmethane, octyl methoxycinnamate, octyl salicylate) in cosmetic products is described. It was based on a high performance liquid chromatographic separation under the condition of isocratic elution with a mixture solution of methanol-THF-water-70% perchloric acid (200:200:160:0.1) by using a column packed with 10 microns YWG-C15 and UV detection. The recoveries (n = 6) were 94.1%-101% and the relative standard deviations(n = 6) for all eleven sunscreen agents were less than 5%. In addition, the results of analysis of 30 samples out of 103 samples of commercial suntan cosmetics performed are reported in this paper.

Chromatography, High Pressure Liquid↗

PubMed1998

[Effect of Acorus tatarinowii Schott. on gastrointestinal myoelectric activity in rats].

The effect of Acorus tatarinowii on the gastrointestinal myoelectric activity and mechanism in rats was studied electrio-physiologically. The result indicates that Acorus tatarinowii helps inhibit the gastrointestinal myoelectric activity. This inhibitory effect is believed to take place through the blocking of cholinergic M and non-cholinergic M receptors, and has nothing to do with adrenergic alpha and beta receptors.

Acorus↗

PubMed1998

A brief history of diagnostic cytology.

Being a discipline specialized for diagnosis of tumors, diagnostic cytology has a history of over 100 years. By exploring the origin, development and its formative process, valuable and special information which are helpful to the general investigation of tumor cases and screening of such patients can be provided.

Cell Biology↗

PubMed1998

[Effects of mitomycin C on haze after photorefractive keratectomy for myopia in rabbits].

OBJECTIVE: To investigate the effects of mitomycin C on haze after photorefractive keratectomy. METHODS: Forty-five rabbits underwent bilateral 193 nm excimer laser photorefractive keratectomy to correct 8 diopters of myopia. All eyes were allocated randomly to be treated with 0.008% mitomycin C during operation, or 0.1% dexamethasone after operation, or no medical treatment as control. Clinical and histopathologic examinations were made with slit-lamp microscope, specular microscope, light microscope and transmission electron microscope. RESULTS: At 4, 8 weeks after operation, the corneal haze was significantly less in mitomycin C group than that in the control group or in dexamethasone group, and the corneal haze was significantly less in dexamethasone group than that in the control group. At 1, 4, 8 weeks, the number of keratocyte in the anterior stroma of ablation area was significantly less in mitomycin C group than in the control group or in dexamethasone group. The difference between dexamethasone group and the control group was insignificant. The changes in time of reepithelialization, thickness of epithelium and keratocyte number of anterior stroma in ablation area were statistically insignificant among all groups. CONCLUSION: Mitomycin C can reduce corneal haze by inhibiting the proliferation of keratocyte and has no toxicity on cornea. Mitomycin C is more effective than dexamethasone on haze.

Animals↗

PubMed1997

Altered phosphorylation of a 91-kDa protein in particulate fractions of rat kidney after protracted 1,25-dihydroxyvitamin D3 or estrogen treatment.

1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] treatment in vitamin D-deficient (-D) rats results in a dose-dependent decrease in phosphorylation of a 91-kDa protein (PP-D91) in particulate fractions of the kidney. This recently reported 1,25(OH)2D3 effect was examined in detail herein. In contrast to the pattern expected of a rapid signal transduction event, time course (4 h-7 days) experiments demonstrated that PP-D91 phosphorylation was not decreased until 3-5 days 1,25(OH)2D3 treatment, resulting in a 61 +/- 3% (P < 0.01, n = 3) decrease in PP-D91 phosphorylation by 7 days. These effects paralleled increases in plasma calcium from 9.3 +/- 0.6 to 13.9 +/- 0.7 mg/dl after 0 vs 7 days 1,25(OH)2D3 treatment, respectively. Subcellular fractionation demonstrated that the renal PP-D91 was predominantly localized and 1,25(OH)2D3-regulated in crude mitochondrial and microsomal fractions. Further, PP-D91 was present and 1,25(OH)2D3-regulated in enriched preparations of both proximal and distal renal tubule segments. Tissue distribution studies demonstrated that the PP-D91 was predominantly present and 1,25(OH)2D3 regulated in the kidney, although low levels of a vitamin D-independent phosphorylated band of similar size were observed in the lung and heart. In contrast to 1,25(OH)2D3, estradiol-17B treatment (1 mg/day x 7 day) significantly (P < 0.01) increased PP-D91 phosphorylation in kidney of both -D and +D rats (increased 118.5 +/- 10.6 and 81.9 +/- 6.3%, respectively). Phosphoamino acid analysis after PP-D91 phosphorylation, isolation, and proteolysis indicated that these hormones alter 32P incorporation into phosphoserine residues. In conclusion, the 1,25(OH)2D3 effect to reduce PP-D91 phosphorylation in particulate fractions of the rat kidney is a protracted, tissue-specific effect which parallels elevated plasma calcium levels in this model. Moreover, renal PP-D91 phosphorylation is differentially regulated by 1,25(OH)2D3 vs E2 treatment and occurs on phosphoserine residues. The parallel between decreased PP-D91 phosphorylation and 1,25(OH)2D3-induced hypercalcemia may suggest a role for PP-D91 in the renal response to hypervitaminosis D.

Animals↗

PubMed1997

Molecular cloning of three rice alpha-tubulin isotypes: differential expression in tissues and during flower development.

We have isolated three rice cDNA sequences coding for divergent isotypes of alpha-tubulin. TubA1 and TubA2 are members of the plant subfamily I of alpha-tubulins whereas TubA3 belongs to subfamily II. The pattern of accumulation of TubA3 mRNA in rice flowers, roots and coleoptile segments treated with auxin differs significantly from what observed for TubA1 and TubA2 mRNAs.

Amino Acid Sequence↗

PubMed1997

Structural and functional analysis of the 5'-flanking region of the human insulin-like growth factor binding protein (IGFBP)-4 gene.

More than 3 kb of the human (h)IGFBP-4 gene 5'-flanking region was sequenced and assessed for promoter activity. The hIGFBP-4 promoter resides within a CpG island and demonstrates strong basal activity in human osteoblast-like osteosarcoma and COS-7 monkey kidney cells. Transient transfection of cells with hIGFBP-4 promoter-linked deletion constructs demonstrated that multiple cooperating cis-acting elements within 836 bp of the 5'-flanking region contributed to overall promoter strength.

Animals↗

PubMed1997

Application of color Doppler ultrasonic examination in deep vein valvular incompetence in lower limbs.

By use of color Doppler Flow Imaging (CDFI), the morphologic and hemodynamic parameters such as the diameters of femoral and popliteal veins, blood flow velocity and the reflux of valve area were examined in lower extremity deep valvular incompetence (DVI) and normal control groups. The purpose was to evaluate the value of CDFI in the diagnosis of DVI. The results demonstrated that the parameters between the two groups had a very significant difference (P < 0.001), indicating that the CDFI is non-invasive, cost-effective and safe and it might serve as a practical tool in the diagnosis of lower extremity deep valvular incompetence.

Adult↗

PubMed1997

An autocrine/paracrine role of human decidual relaxin. I. Interstitial collagenase (matrix metalloproteinase-1) and tissue plasminogen activator.

Decidual and placental relaxins have been proposed as autocrine/ paracrine hormones in the remodeling of collagen in the amnion and chorion in the last weeks of pregnancy. The matrix metalloproteinase-1 (MMP-1) is a key enzyme in the degradation of the interstitial collagens which predominate in the fetal membranes. Distribution of the MMP-1 gene and of the MMP-1 protein was shown by in situ hybridization and immunolocalization, respectively, in amnion, chorion, and decidua collected from patients before the onset of spontaneous labor. The distribution of MMP-1 in the chorionic cytotrophoblast and decidua coincided with that of the human relaxin receptor, detected by tissue section autoradiography in tissues collected at the same stage of pregnancy. Fetal membrane explants were used to study the effect of exogenous human relaxin H2. These responded by a dose-dependent increase in expression of the MMP-1 gene, in its secreted protein, and in its enzyme activity in the medium. A similar dose-dependent increase in the tissue plasminogen activator (tPA) gene and protein upon exposure of the explants to relaxin H2 suggested a coordinated cascade system, resulting in increases in secreted activities of MMP-1, MMP-3 (stromelysin), and MMP-9 (gelatinase B). There was no effect on the genes or proteins for MMP-2 (gelatinase A) or tissue inhibitor of metalloproteinase-1 (TIMP-1), showing the specificity of the response. This coordinated regulation by relaxin H2 of tPA, MMP-1, MMP-3, and MMP-9 would result in more complete degradation of the fetal membrane extracellular matrix components.

Amnion↗

PubMed1997

An autocrine/paracrine role of human decidual relaxin. II. Stromelysin-1 (MMP-3) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1).

Interstitial collagen types I and III are the predominant collagens in the amniotic and chorionic connective tissues. However, this matrix also contains proteoglycans, fibronectin, laminin, and elastin, which together with the collagens may undergo partial degradation prior to fetal membrane rupture at term. In this study, stromelysin (MMP-3) and tissue inhibitor of metalloproteinases-1 (TIMP-1) were immunolocalized in fetal membranes obtained at term prior to labor. MMP-3 stained the cells of the amniotic epithelium, fibroblasts and macrophages of the amniotic and chorionic matrix, and those of the chorionic cytotrophoblast; there was no staining in the maternal decidua. TIMP-1 showed a similar staining pattern, except that the staining was darker in some amniotic epithelial cells and was present in the maternal decidua. The maternal decidua produces the two human relaxins H1 and H2; the latter, when incubated with explants of human fetal membranes, caused a dose-dependent and significant increase in expression of the MMP-3 gene and its secreted protein into the media. A significant effect of relaxin H2 on 92-kDa gelatinase (MMP-9) gene expression was also shown--an effect requiring poly(A)+ RNA rather than total RNA. Both relaxin H1 and H2 caused a significant increase in secretion of MMP-9 protein and its enzyme activity in the media. The magnitude of the effects of the two relaxins was similar, in contrast to findings from other biological studies in which relaxin H2 was shown to be more active. Neither of the relaxins had any effect on 72-kDa gelatinase (MMP-2) activity or on the TIMP-1 protein or its activity. This study suggests that local relaxins may be involved in the degradation of the complex fetal membrane extracellular matrix and may cause activation of an enzyme cascade resulting in fully activated MMP-9. Such effects could be important in the degradative pathways occurring in the amnion and chorion in the peripartal period.

Blotting, Northern↗

PubMed1997

Infiltration of eosinophils into the asthmatic airways caused by interleukin 5.

Interleukin (IL)-5 is thought to play an important role in asthmatic bronchial mucosal inflammation and is a potential therapeutic target. To investigate the effect of IL-5 on the infiltration of eosinophils in airway in vivo, we compared eosinophil counts and their activation status in airways without and after the topical instillation of recombinant human IL-5. Eight subjects with mild atopic asthma underwent initial bronchoscopy during which control bronchoalveolar lavage (BAL) fluid as well as bronchial mucosa were obtained, and at the same time, normal saline and IL-5 were administered to two sublobar segments separately. The second bronchoscopy were carried out and samples from challenged sites were taken 24 h later. It was found that the total eosinophils (BMK-13+ cells) and the activated eosinophils (EG2+ cells) in bronchial mucosa, the eosinophil numbers in BAL fluid, as well as eosinophil cationic protein (ECP) in BAL fluid from saline-challenged segments were not different from those in unchallenged segments. However, a significant eosinophilia was observed in bronchial mucosa and BAL fluid from IL-5-challenged sites. Eosinophil activation, as assessed by secretion of ECP, was also increased significantly in bronchial mucosa and BAL fluid. The results strongly suggested that IL-5 is capable of inducing eosinophil infiltration into the asthmatic airways, as well as the activation of infiltrating eosinophils.

Adult↗

PubMed1997

[Isolation of 28 new STSs at Xq27.3].

A plasmid sublibrary of the 475 kb insert of YAC209G4 was constructed by using pBS II KS vector. The library of 3,500 clones having 100-600 bp inserts was screened with the probe of the 475 kb insert blocked with competitor DNA. Sixty unique single copy clones were found and sequenced. Checking with GenBank, 28 new STSs were obtained. Genbank accession numbers are U26560-26587. Three STSs were tested by PCR with appropriate primers using human genomic DNA as template and showed specific amplification bands as expected.

Chromosome Fragility↗