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Q Nie

Publications and source records attributed to Q Nie.

11 recordsLinked to original sources
PubMed2006

Membrane-associated non-receptors and morphogen gradients.

A previously investigated basic model (System B) for the study of signaling morphogen gradient formation that allows for reversible binding of morphogens (aka ligands) with signaling receptors, degradation of bound morphogens and diffusion of unbound morphogens is extended to include the effects of membrane-bound non-signaling molecules (or non-receptors for short) such as proteoglycans that bind reversibly with the same morphogens and degrade them. Our main goal is to delineate the effects of the presence of non-receptors on the existence and properties of the steady-state concentration gradient of signaling ligand-receptor complexes. Stability of the steady-state morphogen gradients is established and the time to reach steady-state behavior after the onset of morphogen production will be analyzed. The theoretical findings offer explanations for observations reported in several previous experiments on Drosophila wing imaginal discs.

Animals↗
PubMed2005

High diversity of the chicken growth hormone gene and effects on growth and carcass traits.

The chicken growth hormone (cGH) gene plays a crucial role in controlling growth and metabolism, leading to potential correlations between cGH polymorphisms and economic traits. In this study, DNA from four divergent chicken breeds were screened for single nucleotide polymorphisms (SNPs) in the cGH gene using denaturing high-performance liquid chromatography and sequencing. A total of 46 SNPs were identified, of which 4 were in the 5' untranslated region, 1 in the 3' untranslated region, 5 in exons (two of which are nonsynonymous), with the remaining 36 in introns. The nucleotide diversity in the cGH gene ( theta = 2.7 x 10(-3)) was higher than that reported for other chicken genes, even within the same breeds. The associations of five of these SNPs and their haplotypes with chicken growth and carcass traits were determined using polymerase chain reaction-restriction fragment length polymorphism analysis in a F2 resource population cross of two of the four chicken breeds (White Recessive Rock and Xinghua). This analysis shows that, among other correlations, G+1705A was significantly associated with body weight at all ages measured, shank length at three of four ages measured, and average daily gain within weeks 0 to 4. Thus, this cGH polymorphism, or another polymorphism that is in linkage disequilibrium with G+1705A, appears to correspond to a significant growth-related quantitative trait locus difference between the two breeds used to construct the resource population.

Animals↗
PubMed2004

Genomic organisation of the chicken ghrelin gene and its single nucleotide polymorphisms detected by denaturing high-performance liquid chromatography.

(1) Ghrelin is a novel endogenous ligand for the growth hormone secretagogue receptor (GHS-R) and is expressed primarily in the stomach and hypothalamus with the probable function of stimulating GH secretion and food intake both in mammals and poultry. The complete sequences of ghrelin gene have been reported in humans and mice; however, that of chickens remains unclear. (2) Here, we report the complete sequence of chicken ghrelin gene (submitted to Genbank; accession number AY303688), which consists of 5 exons and 4 introns. As in mice, the first exon of chicken ghrelin gene does not encode any amino acid. (3) Scanning point mutations with denaturing high-performance liquid chromatography (DHPLC) using WAVE DNA Fragment Analysis Systems and confirmed with direct sequencing for polymerase chain reaction (PCR) products, we analysed the single nucleotide polymorphisms (SNPs) in the entire gene of chicken ghrelin. (4) Results showed that there were 19 SNPs in chicken ghrelin gene, and most of these SNPs were scattered in the 4 introns. In these SNPs, one mutation in exon 5 (A2355G) led to the change of amino acid from glutamine to arginine (Gln 113 Arg): as a result a different ghrelin precursor instead of a mature peptide was produced. In addition, one SNP in 5'UTR (C223G) determined the presence or absence of a potential binding site of transcription factor serum response factor (SRF), which might affect the expression of chicken ghrelin gene. Some of the SNPs detected in the present study could be used in quantitative trait loci (QTL) mapping for growth characters in chickens. (5) Because one SNP is located in a polymorphic site of restriction enzyme PagI of intron 4, it was possible to design a PCR-RFLP procedure and analyse the diversity of 10 chicken populations. Results showed the allelic frequencies of C2100T differ among these breeds, however, no significant difference was observed between imported breeds and Chinese native ones, nor between egg layers and meat type chickens. A chi-square test showed that 4 chicken populations of Beijing Fat, Xinghua, Recessive White and Silky followed the Hardy-Weinberg equilibrium.

Amino Acid Sequence↗
PubMed2001

[Expression and significance of tissue inhibitors of metallproteinases-1 and -2 in serum and liver tissue of patients with liver cirrhosis].

OBJECTIVE: To investigate the expression and location of tissue inhibitors of metallproteinases-1 and -2 (TIMP-1 and TIMP-2) in liver tissue of patients with cirrhosis and to investigate the correlation between TIMPs in liver and those in serum. METHODS: TIMP-1 and TIMP-2 in the serum of 106 patients with liver cirrhosis were detected by solid-phase absorption to sensitized erythrocytes (SPASE). The expression of TIMP-1 and TIMP-2 related antigens in liver biopsy specimens from 30 patients with liver cirrrhosis was detected by immunohistochemical method with specific monoclonal antibody (McAb), and the results thus obtained were compared with the results of the seral TIMPs from the same patients. 10 normal livers were used as controls. RESULTS: The positive rates of TIMP-1 and TIMP-2 in the 106 serum samples of patients with cirrhosis were 73.58% and 61.32% respectively. TIMP-1 and TIMP-2 related antigens were detected in all of the 30 liver tissues from patients with liver cirrhosis and the expression of TIMP-1 was higher than that of TIMP-2 (P < 0.01). The staining signal of TIMP-1 and TIMP-2 related antigen was mainly located in the cytoplasm of liver cells. There was no signal in nuclear of liver cells. None of the normal liver tissues was positive in expression of TIMP-related antigen. The positive rate was 100% for serum TIMP-1 and 77% for serum TIMP-2. CONCLUSION: Expression of TIMPs at different degrees can be found in liver tissue with cirrhosis. TIMPs are located in cytoplasm of liver cells of patients with cirrhosis. There is a significant correlation between serum TIMPs level and liver TIMPs level. Serum TIMP-1 and TIMP-2 can be used as diagnostic indexes for liver fibrosis in chronic liver diseases.

Adult↗
PubMed2000

[Analysis and comparison of dental arch symmetry between different Angle's malocclusion categories and normal occlusion].

OBJECTIVE: To analyze and compare dental arch symmetry between different Angle's malocclusion categories and normal occlusion. METHODS: 300 subjects were divided into four different malocclusion groups and normal occlusion group. Data points representing the dental arches on the casts were precisely marked by YM-2115 three Dimension Measuring Machine. Arch forms were fitted with conic sections, and then dental arch symmetry was analyzed by rotation angle. RESULTS: There were no absolute symmetric dental arch, and the direction of asymmetry was unsteady. In normal occlusion, dental arch was generally symmetric, but there was asymmetry in a very small degree. As to malocclusion, the frequency and degree of dental arch asymmetry were higher than that of normal occlusion, and the lower arch showed more asymmetry than the upper arch except ClassIII. The frequency of asymmetry in ClassII2 and ClassIII groups was higher than that in other malocclusion groups. CONCLUSION: The frequency and degree of dental arch asymmetry were different in different malocclusion groups.

Adolescent↗
PubMed1999

Comparison of intermaxillary tooth size discrepancies among different malocclusion groups.

The purpose of this study was to determine whether there is a prevalent tendency for intermaxillary tooth size discrepancies among different malocclusion groups. This study consisted of 60 subjects who served as the normal occlusion group and 300 patients divided into 5 malocclusion groups (ie, Class I with bimaxillary protrusion, Class II Division 1, Class II Division 2, Class III, and Class III surgery). Tooth size measurements were performed on the models of normal occlusion and pretreatment models of patients by the Three Dimension Measuring Machine. Moreover, tooth size ratios, analyzed as described by Bolton and the Student t test showed no sexual dimorphism for these ratios in each of 6 groups, so the sexes were combined for each group. Then these ratios were compared among different malocclusion groups. The results showed no significant difference between subcategories of malocclusion, so these groups were combined. There were now 120 cases in each of 3 categories: Class I, Class II, and Class III. A significant difference was found for all the ratios between the groups, the ratios showing that Class III > Class I > Class II. It demonstrated that intermaxillary tooth size discrepancy may be one of the important factors in the cause of malocclusions, especially in Class II and Class III malocclusions. Thus this study proved the fact that Bolton analysis should be taken into consideration during orthodontic diagnosis and therapy.

Adolescent↗
PubMed1999

Front formation in an active scalar equation.

We study the formation of thermal fronts in an active scalar equation that is similar to the Euler equation. For a particular initial condition, an earlier candidate for finite-time blowup, the front forms in a generalized self-similar way with constant hyperbolicity at the center. The behavior belongs to a class of scenarios for which finite-time blowup is impossible. A systematic exploration of many different initial conditions reveals no evidence of singular solutions.

Journal Article↗
PubMed1997

Inhibition of mononuclear cell recruitment in aortic intima by treatment with anti-ICAM-1 and anti-LFA-1 monoclonal antibodies in hypercholesterolemic rats: implications of the ICAM-1 and LFA-1 pathway in atherogenesis.

To investigate the mechanism(s) for mononuclear cell recruitment in the arterial wall during the development of atherosclerosis, we studied intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) expression in aortic intima from diet-induced hypercholesterolemic rats. ICAM-1 was barely found in the aortic walls from rats fed a normal chow diet; however, in rats on a cholesterol-rich diet for 4 weeks, ICAM-1 expression was markedly enhanced in the intimal endothelial cells of aortas. Enhanced expression of ICAM-1 on endothelial cells especially along the cellular borders in the abdominal aorta was almost invariably associated with increased adherence of mononuclear cells. Compared to control animals, in hypercholesterolemic rats, the numbers of intimal macrophages and T lymphocytes adhering to the "lesion-prone" areas of the abdominal aorta were significantly increased by 5.9-fold (p < 0.001) and 2.2-fold (p < 0.001), respectively. More than 85% of adherent macrophages exhibited LFA-1 antigen on the cellular membrane surface as assessed by immunostaining. To examine the participation of ICAM-1 and LFA-1 in adherence and migration of mononuclear cells, we administered monoclonal antibodies (mAb) against either ICAM-1 or LFA-1 into hypercholesterolemic rats after they were fed a cholesterol-rich diet for 2 weeks. Two weeks after the mAb treatment, the number of macrophages adhering to the intima was significantly inhibited by 42% (p < 0.001) with anti-ICAM-1 mAb and by 31% (p < 0.001) with anti-LFA-1 mAb compared to controls injected with mouse IgG. Combined injection with these two mAb increased the reduction of the number of macrophages in the intima to 58%. Furthermore, we found that the decrease in the number of macrophages that adhered to the intima was almost exclusively due to the reduction of LFA-1-positive macrophages. These results suggest that the ICAM-1 and LFA-1 pathway is involved in mononuclear-endothelial cell interaction during cholesterol-rich diet-induced atherogenesis.

Animals↗
PubMed1990

The effect of naftidrofuryl, a 5-HT2 antagonist, on collateral vascular responses to serotonin and to platelet activation.

Collateral arterial supersensitivity to serotonin has been attributed to a 5-HT2 receptor mechanism because of the effectiveness of ketanserin in reversing that vasoconstrictor response. To assess that hypothesis we employed a chemically unrelated agent, naftidrofuryl, and assessed the responses of the collateral arterial supply 2 weeks after superficial femoral artery ligation to serotonin or to platelet activation induced by endothelial injury in 25 rabbits. Naftidrofuryl was effective in reversing serotonin-induced vasoconstriction in doses ranging from 0.3 to 3.0 micrograms/kg/min. Higher doses reduced blood pressure sufficiently that collateral arterial attenuation ensued. When collateral arterial vasoconstriction was induced by endothelial injury, naftidrofuryl in doses of 1.0 and 3.0 micrograms/kg/min reversed the attenuation (p < 0.001) in a dose-dependent fashion. In the absence of vasoconstriction induced by serotonin or platelet activation, naftidrofuryl in these doses did not produce vasodilatation, suggesting that the agent acted as a blocker rather than as a direct vasodilator. The observations strengthen the hypothesis that supersensitivity of collateral arterial vessels to serotonin reflects a 5-HT2 receptor mechanism.

Animals↗
PubMedDate not supplied

New variations in intron 4 of growth hormone gene in Chinese native chickens.

Polymorphism in intron 4 of chicken growth hormone (cGH) gene was studied in 20 Chinese native chicken populations and broiler or layer populations. A total of eight restriction digestion profiles were identified in intron 4 and confirmed by sequencing. Among 20 populations, there were distinctively different allele numbers and frequencies of intron 4 restriction fragment length polymorphisms (RFLPs) between Chinese native chickens and broilers or layers. Two new alleles, allele D and allele E, were identified in Taihe Silkies. Allele D was also identified in other Chinese native breeds and a 50 bp fragment deletion was identified in allele E.

Animals↗