Biomedical subjects

N Qu

Publications and source records attributed to N Qu.

7 recordsLinked to original sources

PubMed2001

[Effect of methionine supplementation on the selenium bioavailability in rats fed on grains from Keshan disease endemic area].

In order to study the effect of dietary methionine on tissue selenium and glutathione peroxidase activity(GPX) in rats fed on grains from Keshan Disease endemic area, a nonpurified selenium (Se) deficient diet (containing Se 0.007 mg/kg diet) taken from Keshan Disease endemic area was supplemented with selenomethionine (SeMet) to provide selenium content in diet for 0.007, 0.06 and 0.50 mg/kg and added or not added with DL-methionine (Met) 4 g/kg to make 6 kinds of diet. Fifty four male weanling Wistar rats were randomly divided into 6 groups, consuming each one of the 6 diets for 8 weeks. The Se content and GPX activity in tissues of animals with Met supplementation were compared with those without Met supplementation. The results showed that adding Met did not result in significant changes of tissue Se content and GPX activity in animals having dietary Se of 0.007 mg/kg, except for lower muscle Se content. However, in animals having dietary Se of 0.06 mg/kg and supplementing Met resulted in selenium redistribution in tissues-decrease of Se content in muscle, increase of Se content in liver and blood and significant elevation of GPX activity in all tissues. In animals having methionine-added and dietary Se of 0.50 mg/kg, tissue Se content declined to various extent, while GPX activity remained unchanged. The results suggest that SeMet (main chemical form of Se in cereals) is preferentially incorporated into body protein when dietary methionine is limited. Once Met is supplemented, dietary SeMet would provide more Se for the syntheses of GPX and other selenoproteins. The results further suggest that marginal deficiency in sulfur-containing amino acids in the diet from Keshan Disease endemic area might be an additional factor for the development of Keshan Disease under selenium deficiency.

Animals↗

PubMed2001

[Studies on the determination of serum thymic factor by capillary zone electrophoresis].

The determination of serum thymic factor (FTS) by capillary zone electrophoresis was described. The optimum ionic concentration and the pH value of buffer system was examined through orthogonal analysis. The optimum conditions found to be 0.05 mol/L sodium tetraborate, 0.01 mol/L phosphate buffer at pH 8.70, working voltage at 12 kV and wavelength at 200 nm. The recoveries for FTS standards added to the bovine serum albumin and serum samples were measured. The values of the relative standard deviation(RSD), recovery and detection limit were 7.62%, 80.28% and 40 ng/ml respectively. The development of this method provide another way for studying the relations of zinc and thymic factor and investigating the effect of zinc on immune function.

Electrophoresis, Capillary↗

PubMed1998

An ethanol inducible gene switch for plants used to manipulate carbon metabolism.

Many transgenic plant studies use constitutive promoters to express transgenes. For certain genes, deleterious effects arise from constant expression in all tissues throughout development. We describe a chemically inducible plant gene expression system, with negligible background activity, that obviates this problem. We demonstrate its potential by showing inducible manipulation of carbon metabolism in transgenic plants. Upon rapid induction of yeast cytosolic invertase, a marked phenotype appears in developing leaves that is absent from leaves that developed before induction or after it has ceased.

Alcohol Dehydrogenase↗

PubMed1997

Mutations in the Fas antigen in patients with multiple myeloma.

Programmed cell death, or apoptosis, is well documented as a physiological means of eliminating activated lymphocytes and maintaining immune homeostasis. Apoptosis has also been implicated in the targeting of tumor cells by cytotoxic T lymphocytes and natural killer cells. One of the two primary mechanisms used in cell-mediated cytotoxicity is the Fas/FasLigand system. Activated or transformed cells expressing the Fas antigen on their surface are susceptible to killing by immune effector cells that express the Fas ligand. Many neoplastic cells, including those derived from patients with multiple myeloma, express Fas antigen on their surface, but do not undergo apoptosis in response to antigen crosslinking. One possibility for the lack of Fas-mediated apoptosis includes mutations in the Fas antigen. Loss of function mutations in the Fas antigen have been associated with congenital autoimmune disease in humans, and have been defined as the genetic defect the in lpr mice. Mutations in the Fas antigen have not been previously described in cancer patients. In this study, we show that mutations occur in the Fas antigen which may cause loss of function and contribute to the pathogenesis of the neoplastic disease, multiple myeloma. Using reverse transcriptase-polymerase chain reaction (RT-PCR), single-stranded conformation polymorphism (SSCP) analysis, and DNA sequencing, we examined the cDNA structure of the Fas antigen in 54 bone marrow (BM) specimens obtained from myeloma patients. Six patient specimens (11%) did not express detectable levels of Fas antigen mRNA. Of the 48 BM specimens which did express Fas antigen, 5 (10%) displayed point mutations. All of the mutations identified were located in the cytoplasmic region of the Fas antigen known to be involved in transduction of an apoptotic signal. Two separate individuals demonstrated an identical mutation at a site previously shown to be mutated in the congenital autoimmune syndrome, ALPS. One patient exhibited a point mutation at a site only two amino acids removed from the documented lesion of the lprcg mouse. Although the functional status of these point mutations remains to be determined, we propose that Fas antigen mutations may contribute to the pathogenesis and progression of myeloma in some patients.

Amino Acid Substitution↗

PubMed1997

[The Chinese total diet study in 1992--macro elements and trace elements].

Ten macro elements and trace elements were directly determined in the 1992 total diet study conducted in four districts of China from north to south. The intake of these elements was evaluated. The levels of intake for seasonal variation and for different age groups were reported. The results showed that the intakes of Ca, P, K, Mg, Zn, Se and Cu were low in children. The intake of Ca, P and Zn was insufficient for adults. The intakes of other seven elements reached or approached their RDA levels, but there were big differences among the 4 districts. The relationships between intakes of Ca/P and Na/K as well as Fe and Cu and iron difficiency anemia were discussed.

Adolescent↗

PubMed1995

Isolation of differentially expressed sequence tags from steroid-responsive cells using mRNA differential display.

Transcriptional control of steroid-regulated gene networks by nuclear receptor proteins results in the coordinate expression of a limited number of target genes. Although much is known about the structure and function of steroid receptors, relatively few cell-specific steroid-regulated genes have been isolated and characterized. In this paper we describe results using mRNA differential display reverse transcriptase PCR (DDPCR) to identify and isolate short cDNA sequence tags from thymocyte and prostate cells under various hormone conditions. Using this technique we have isolated several differentially expressed sequence tags (DESTs) from the mouse thymocyte cell line WEHI 7.2. Two of these DESTs, GIG10 and GIG18, are rapidly induced by dexamethasone within 2 h of treatment. GIG10 is a novel sequence and GIG18 is the mouse homologue of a human expressed sequence tag isolated from activated B lymphocytes. We also used DDPCR to isolate DESTs from androgen-modulated rat ventral prostate tissue, one of which we characterized and found to correspond to the 3' end of prostatic spermine binding protein mRNA, a known androgen-regulated gene. Modifications of the original DDPCR protocol, which we found can potentially decrease the frequency of isolating false-positive DESTs, are described and the merits of DDPCR, relative to other differential cDNA cloning strategies, are discussed.

Androgens↗

PubMed1995

[Effect of bushen shengxue recipe on EPO gene expression of chronic renal insufficiency anemia in rats].

The rats were fed with adenine to establish the chronic renal insufficiency anemia model, and the relationship between renal functional impairment and reticulocytes, hemoglobin and erythropoietin (EPO) synthesis was observed to explore the mechanism of Bushen Shengxue drugs in improving the hemopoietic function. The results showed that the Bushen Shengxue drugs could significantly lower the serum creatinine and blood urea nitrogen of renal insufficiency rats, and through the promotion of EPO gene expression, the animals' anemic status was improved.

Anemia↗