Biomedical subjects

M Xie

Publications and source records attributed to M Xie.

At least 19 recordsLinked to original sources

PubMed2006

The expression of antiapoptotic protein survivin is transcriptionally upregulated by DEC1 primarily through multiple sp1 binding sites in the proximal promoter.

Human differentially expressed in chondrocytes (DEC), mouse stimulated with retinoic acid and rat split and hairy related proteins constitute a structurally distinct class of the basic helix-loop-helix proteins. DEC1 is abundantly expressed in tumors and protects against apoptosis induced by serum starvation. In this study, we report that DEC1 antiapoptosis is achieved by inducing survivin, an antiapoptotic protein. In paired tumor-normal tissues, survivin and DEC1 exhibited a paralleled expression pattern. Tetracycline-induced expression of DEC1 in stable lines proportionally increased the expression of survivin. In reporter assays, DEC1 transactivated the survivin promoter but repressed the DEC2 promoter. In contrast to the repression, the activation was delayed and varied depending on serum concentrations and cycle blockers. Studies with reporter mutants located, in the survivin promoter, two Sp1 sites that supported DEC1 transactivation. Electrophoretic mobility shift assay and chromatin immunoprecipitation detected the presence of DEC1 in the survivin promoter. These findings establish that the survivin gene is a transcription target of DEC1, and induction of survivin is at least in part responsible for DEC1 antiapoptosis.

Adult↗

PubMed2006

Methionine requirements of male white Peking ducks from twenty-one to forty-nine days of age.

A dose-response experiment with 6 dietary methionine levels (0.20, 0.275, 0.35, 0.425, 0.50, and 0.575%) was conducted with male White Peking ducklings to estimate the methionine requirement of growing ducks from 21 to 49 d of age. One-day-old male White Peking ducklings were fed common starter diets from hatching to 21 d of age and then fed the experimental diets from 21 to 49 d of age. Three hundred thirty-six 21-d-old birds were allotted to 24 pens with 14 birds per pen according to similar pen weight. There were 6 dietary treatments, each containing 4 replicate pens. At 49 d of age, weight gain, feed intake, and feed/gain of ducks from each pen were measured, and 2 ducks selected randomly from each pen were slaughtered to evaluate the yields of abdominal fat, breast meat (including pectoralis major and pectoralis minor), and leg meat (including thigh and drum stick). Significant effects of dietary methionine on weight gain, breast meat, and abdominal fat were observed. Both weight gain and breast meat yield showed significant quadratic response to increasing dietary methionine, and abdominal fat decreased linearly (P < 0.05). According to the quadratic model, the optimal methionine requirement of male White Peking ducks from 21 to 49 d of age for maximum weight gain and breast meat yield were 0.377 and 0.379%, respectively.

Aging↗

PubMed2004

Interrelationship between methionine and cystine of early Peking ducklings.

A 4 x 5 factorial experiment containing 4 cystine levels (0.325, 0.406, 0.487, or 0.568%) and 5 methionine levels (0.285, 0.385, 0.485, 0.585, or 0.685%) was conducted to evaluate the interrelationship between methionine and cystine in corn-peanut meal diet for Peking ducklings from hatch to 21 d of age. Eight hundred 1-d-old male white Peking ducklings were assigned to 20 experimental treatments. All treatments were replicated 4 times using 10 ducklings per pen. As dietary methionine level increased, weight gain and feed intake increased and then decreased; the quadratic response of weight gain was significant (P < 0.05). The methionine requirement for maximum efficiency of feed utilization (0.585%) was higher than for maximum weight gain (0.485%). According to the quadratic model, the optimal methionine requirement of Peking ducklings from hatch to 21 d of age was 0.481% (95% of the level at maximum response). The plasma uric acid concentration was very low (P < 0.05) when dietary methionine was 0.485%. When dietary methionine was excessive (0.685%), the plasma homocysteine concentration increased (P < 0.05). On the other hand, the cystine requirement of ducklings from hatch to 21 d of age was not more than 0.325%. A high level of cystine (0.568%) depressed weight gain and feed intake (P < 0.05), but cystine supplementation in the diets lowered the plasma homocysteine concentration (P < 0.05). There were no significant interactions between methionine and cystine on growth performance, plasma uric acid, and plasma homocysteine.

Animal Feed↗

PubMed2002

Alpha-glucosidase inhibition from a Chinese medical herb (Ramulus mori) in normal and diabetic rats and mice.

Alpha-glucosidase inhibitors are oral antidiabetic drugs. A traditional Chinese medical herb, Sangzhi (Ramulus mori), appears to have properties similar to those of alpha-glucosidase inhibitors. The effects of an aqueous extract of Shangzhi (SZ) were studied in normal and alloxan diabetic rats and mice, and these results compared with those for acarbose, an alpha-glucosidase inhibitor. In our grade-dose studies, SZ was found to lower and prolong the zenith of blood glucose concentration (ZBG) after sucrose or starch loading and stabilize blood glucose levels in fasting normal and alloxan diabetic mice. After 2 weeks of SZ administration with high-calorie chow or a normal diet, the fasting and non-fasting blood glucose concentrations in alloxan diabetic mice and rats were decreased. In alloxan rats, the blood fructosamine concentration was lowered. Results for acarbose and SZ were similar. These indicate that SZ has alpha-glucosidase inhibitory effects.

Alloxan↗

PubMed2001

Regression analysis of group testing samples.

This paper develops a general regression methodology that relates the group testing responses to individual covariate information. It can be used to study samples from a group testing procedure and to deal with a wide range of regression problems. A detailed illustration of the methodology is provided for a group testing procedure proposed by Gastwirth and Hammick. To demonstrate the utility of the method, simulation studies are performed on an HIV antibody testing data set published by Nusbacher et al.

Blood Donors↗

PubMed2001

Persistent activation of NF-kappa B by the tax transforming protein involves chronic phosphorylation of IkappaB kinase subunits IKKbeta and IKKgamma.

The Tax transforming protein encoded by human T-cell leukemia virus type 1 (HTLV1) persistently activates transcription factor NF-kappaB and deregulates the expression of downstream genes that mediate cell cycle entry. We recently found that Tax binds to and chronically stimulates the catalytic function of IkappaB kinase (IKK), a cellular enzyme complex that phosphorylates and inactivates the IkappaB inhibitory subunit of NF-kappaB. We now demonstrate that the IKKbeta catalytic subunit and IKKgamma regulatory subunit of IKK are chronically phosphorylated in HTLV1-infected and Tax-transfected cells. Alanine substitutions at Ser-177 and Ser-181 in the T loop of IKKbeta protect both of these IKK subunits from Tax-directed phosphorylation and prevent the induction of IkappaB kinase activity. Each of these inhibitory effects is recapitulated in Tax transfectants expressing the bacterial protein YopJ, a potent in vivo agonist of T loop phosphorylation. Moreover, ectopically expressed forms of IKKbeta that contain glutamic acid substitutions at Ser-177 and Ser-181 have the capacity to phosphorylate a recombinant IKKgamma substrate in vitro. We conclude that Tax-induced phosphorylation of IKKbeta is required for IKKbeta activation, phosphoryl group transfer to IKKgamma, and acquisition of the deregulated IKK phenotype.

Bacterial Proteins↗

PubMed2001

Bidirectionalization of polar promoters in plants.

A typical eukaryotic promoter consists of a minimal promoter and other upstream cis elements. The minimal promoter is essentially a TATA box region where RNA polymerase II, TATA-binding protein (TBP), and TBP-associated factors (TAFs) bind to initiate transcription, but minimal promoters alone have no transcriptional activity. The cis elements, to which tissue-specific or development-specific transcription factors bind, individually or in combination, determine the spatio-temporal expression pattern of a promoter at the transcriptional level. The arrangement of upstream cis elements followed by a minimal promoter sets the polarity of the promoter. Promoters in plants that have been cloned and widely used for both basic research and biotechnological application are generally unidirectional, directing only one gene that has been fused at its 3' end (downstream). It is often necessary to introduce multiple genes into plants for metabolic engineering and trait stacking. It is also desirable to minimize or avoid repeated use of a single promoter that may cause transcriptional gene silencing. Here we describe a strategy to make polar promoters bidirectional so that one promoter can direct the expression of two genes, one on each end of the promoter.

Arabidopsis↗

PubMed2001

Nitric oxide up-regulates ferritin mRNA level in snail neurons.

We cloned and sequenced the ferric ion-binding protein, ferritin, from the nervous system of the pulmonate snail, Helix pomatia. Helix H-ferritin cDNA contains a 519-bp open reading frame (ORF) and predicts an iron-responsive element (IRE) at the 5'-untranslated region (5'-UTR) of the ferritin mRNA. The deduced amino acid sequence revealed 86% similarity with Lymnaea stagnalis ferritin and about 70% similarity with vertebrate H-ferritin. While secreted ferritin isoforms contain a signalling sequence at their N-terminal end, Helix ferritin does not contain this sorting signal indicating that it is restricted to the cytoplasm. The amino acid ligands at positions Glu25, Tyr30, Glu59, Glu60, His63, Glu105 and Gln139 indicate an active ferroxidase site in Helix ferritin. In situ hybridization visualized ferritin mRNA in neuronal cell bodies but not in the neuropil. In contrast, ferritin-immunoreactive protein was localized in cell bodies and neurites. We further demonstrate that the NO donors S-nitroso-N-acetylpenicillamine (SNAP), or hydroxylamine (HA), increase the intracellular ferritin mRNA level by about 55%. In conclusion, our findings show that Helix neurons express an intracellular H-ferritin isoform and suggest that iron and NO metabolism are coupled.

Amino Acid Sequence↗

PubMed2001

Presence of antibody against the inducible Hsp71 in patients with acute heat-induced illness.

Antibodies against heat shock or stress proteins (Hsps) have been reported in a number of diseases in which they may be involved in the pathogenesis of the disease or may be of use for prognosis. Heat-induced diseases, such as heat cramps, heat exhaustion, or heat stroke, are frequent in hot working or living environments. There are still few investigations on the presence and possible significance of autoantibodies against Hsps in heat-induced illnesses. Using an immunoblotting technique with recombinant human Hsps, we analyzed the presence and titers of antibodies against Hsp60, Hsp71, and Hsp90alpha, and Hsp90beta in a group of 42 young male patients who presented with acute heat-induced illness during training. We also examined the presence of antibody against Hsp71 in a second group of 57 patients with acute heat-induced illness and measured the changes in titers of anti-Hsp71 antibodies in 9 patients hospitalized by emergency physicians. In the first group of young persons exercising in a hot environment, the occurrence of antibodies against Hsp71 and Hsp90alpha was significantly higher among individuals with symptoms of heat-induced illness (P < 0.05) than in the matched group of nonaffected exercising individuals. Moreover titers of antibody against Hsp71 were higher in individuals of the severe and mild heat-induced illness groups, the highest titer being found in the most severe cases. The results from the second group of 57 heat-affected patients exposed to extreme heat were similar. Again, patients with the more severe heat-induced symptoms showed a significantly higher incidence of antibodies to Hsp71 than controls and the titer of anti-Hsp71 was higher in the severely affected group. Finally, in a study of 9 patients, it was observed that the titer of anti-Hsp71 decreased during recovery from severe heat symptoms. These results suggest that measurement of antibodies to Hsps may be useful in assessing how individuals are responding to abnormal stress within their living and working environment and may be used as one biomarker to evaluate their susceptibility to heat-induced diseases.

Adolescent↗

PubMed2001

Detection of recombinant human erythropoietin abuse in athletes utilizing markers of altered erythropoiesis.

BACKGROUND AND OBJECTIVES: The detection of recombinant human erythropoietin (r-HuEPO) abuse by athletes remains problematic. The main aim of this study was to demonstrate that the five indirect markers of altered erythropoiesis identified in our earlier work were reliable evidence of current or recently discontinued r-HuEPO use. A subsidiary aim was to refine weightings of the five markers in the initial model using a much larger data set than in the pilot study. A final aim was to verify that the hematologic response to r-HuEPO did not differ between Caucasian and Asiatic subjects. DESIGN AND METHODS: Recreational athletes resident in Sydney, Australia (Sydney, n = 49; 16 women, 33 men) or Beijing, China (Beijing, n=24; 12 women, 12 men) were randomly assigned to r-HuEPO or placebo groups prior to a 25 day administration phase. Injections of r-HuEPO (or saline) were administered double-blind at a dose of 50 IU/kg three times per week, with oral iron (105 mg) or placebo supplements taken daily by all subjects. Blood profiles were monitored during and for 4 weeks after drug administration for hematocrit (Hct), reticulocyte hematocrit (RetHct), percent macrocytes (%Macro), serum erythropoietin (EPO) and soluble transferrin receptor (sTfr), since we had previously shown that these five variables were indicative of r-HuEPO use. RESULTS: The changes in Hct, RetHct, %Macro, EPO and sTfr in the Sydney trial were qualitatively very similar to the changes noted in our previous administration trial involving recreational athletes of similar genetic origin. Statistical models developed from Fisher's discriminant analysis were able to categorize the user and placebo groups correctly. The same hematologic response was demonstrated in Beijing athletes also administered r-HuEPO. INTERPRETATION AND CONCLUSIONS: This paper confirms that r-HuEPO administration causes a predictable and reproducible hematologic response. These markers are disturbed both during and for several weeks following r-HuEPO administration. This work establishes an indirect blood test which offers a useful means of detecting and deterring r-HuEPO abuse. Ethnicity did not influence the markers identified as being able to detect athletes who abuse r-HuEPO.

Adult↗

PubMed2001

Psychopathology as a predictor of adolescent drug use trajectories.

The authors examined early psychopathology as a predictor of trajectories of drug use from ages 13-18 years. Six years of annual data were analyzed for 506 boys using a mixed effects polynomial growth curve model. They tested whether distinct measures of psychopathology and behavioral problems (i.e., attention-deficit/hyperactivity disorder, oppositional defiant disorder, conduct disorder, depression, and violence) assessed in early adolescence could prospectively predict level and change in alcohol and marijuana use. Higher levels of all of the types of psychopathology predicted higher levels of alcohol use, and higher levels of attention-deficit/hyperactivity disorder, conduct disorder, and violence predicted higher levels of marijuana use. Only conduct disorder predicted linear growth in alcohol use, and none of the measures predicted growth in marijuana use. The results suggest that drug use prevention programs should target youths with early symptoms of psychopathology.

Adolescent↗

PubMed2001

[Expression of Th1, Th2-typed cytokines and its significance in nasal polyps].

OBJECTIVE: To evaluate the possible role of cytokines in pathophysiology and treatment of nasal polyps. METHOD: The expressions of Th1-typed cytokines IFN-gamma, IL-2, IL-12 and Th2-typed cytokines IL-4, IL-5, IL-8, IL-10, IL-13 were investigated with enzyme-linked immune sorbent assay(ELISA) in 25 patients with nasal polyps. RESULT: There was a significant upregulation of Th2-typed cytokines IL-4, IL-5, IL-8, IL-10, IL-13 in nasal polyps compared with normal nasal mucosa, especially IL-4 and IL-5 (3.9 times and 8.8 times higher than normal mucous respectively) while the expression of Th1-typed cytokines IFN-gamma, IL-2, IL-12 decreased after treated with local glucocorticoid. The levels of Th2-typed cytokines decreased significantly and Th1-typed cytokines had no obvious change. CONCLUSION: The upregulation of Th2-typed cytokines such as IL-4, IL-5, IL-8, IL-10, IL-12 may play an important role in the pathophysiology of nasal polyps and Th2-typed cytokines can be viewed as a target of treatment to nasal polyps.

Adolescent↗

PubMed2001

[Revision endoscopic sinus surgery on chronic sinusitis and polyps].

OBJECTIVE: To study the indications, surgical landmarks, surgical significance, complications and operative avoidance of revision endoscopic sinus surgery on chronic sinusitis and polyps. METHOD: We performed revision endoscopic sinus surgery on 112 cases of chronic sinusitis and polyps under controlled hypotension anaesthesia by using the Messerklinger technique and Stryker debrider. RESULT: 89 cases were successful and 17 unresolved, 6 failed, all the complications consist of cerebrospinal fistula in one, orbital hematoma in four, increased tearing in three and profuse bleeding in 6 patients. CONCLUSION: Revision endoscopic sinus surgery was advised in case of sinuous obstruction caused by uncontrolled lesions under postoperative care, which can do good for adhesion and obstruction except nasal polyposis. The remanet of the middle turbinate and the upper arch of choana were helpful operative landmarks. Preoperative CT scan decrease the complications.

Adolescent↗

PubMed2001

[Effect of transduction bax gene on experimental nasopharyngeal carcinoma].

OBJECTIVE: To evaluate the effect of transduction bax gene on nasopharyngeal carcinoma (NPC). METHODS: The transduced bax gene was mediated by Dosper lipidsome to the HNE-1 cell lines, and confirmed by immunofluorescent stain. The apoptosis of the cell lines was studied by MTT stain and flow cytometry and the growth of implanted tumor in naked mouse after local injection of bax geneobserved. RESULTS: Instantaneous expression of bax gene in HNE1 cell lines was testified by immunofluorescent stain after transduction for 48 hours, the apoptotic index were 10.7% and 69.4% for pre- and post-transduction, respectively. MTT stain showed the values of A in 490 nm after transduction to be 2.004(36 h) and 1.902(48 h). The diameter of implanted tumor mass was (1.8 +/- 0.64) cm and (3.0 +/- 0.44) cm in experimental and control groups, respectively. CONCLUSION: The transduction bax gene can enhance the apoptosis of HNE1 cell lines and prevent growth of implanted tumor.

Animals↗

PubMed2001

[Expressions of vascular endothelial growth factor and basic fibroblast growth factor in nasal polyp and its role].

OBJECTIVE: To evaluate the role of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor(bFGF) in the pathophysiology of nasal polyp. METHODS: Thirty-nine patients with nasal polyp were divided into two groups: group A(representing type 1 and type 2 phase 1-2) and group B (representing type 2 phase 3 and type 3). The expression of VEGF and and bFGF in both groups were studied with immunohistochemical method. RESULTS: VEGF and bFGF were not detected in norms. The detection rates of VEGF and bFGF were 59%, 41%, and 71%, 80% in group A and group B respectively. The positive rate and the number of positive cells were higher significantly in group B than that in group A. VEGF and bFGF were located mainly in the inflammatory cells and epithelial cells around the basilar membrane and inflammatory cells and endothelial cells around the vessel. CONCLUSIONS: The overexpression of VEGF and bFGF in nasal polyp may contribute to the growth of vessels, accumulation of inflammatory cells, as a result, to enhance the development of nasal polyposis. This phenomenon maybe an important histological mark distinguishing ordinary polyp from polyposis.

Adolescent↗

PubMed2000

Hypomethylation and overexpression of c-jun and c-myc protooncogenes and increased DNA methyltransferase activity in dichloroacetic and trichloroacetic acid-promoted mouse liver tumors.

Dichloroacetic acid (DCA) and trichloroacetic acid (TCA) are mouse liver carcinogens. Methylation of the c-jun and c-myc genes, expression of both genes and DNA methyltransferase (DNA MTase) activity were determined in liver tumors initiated by N-methyl-N-nitrosourea and promoted by DCA and TCA in female B6C3F1 mice. Hypomethylated and over-expression of c-jun and c-myc genes were found in DCA- and TCA-promoted liver tumors. DNA MTase activity was increased in tumors while decreased in non-involved liver. Thus, DCA- and TCA-promoted carcinogenesis appears to include decreased methylation and increased expression of c-jun and c-myc genes in the presence of increased DNA MTase activity.

Alkylating Agents↗

PubMed2000

In-use testing of extemporaneously prepared suspensions of second generation non-nucleoside reversed transcriptase inhibitors in support of phase I clinical studies.

DPC 961 and 963 are two of a series of prospective second generation non-nucleoside reverse transcriptase inhibitors (NNRTIs) being considered for the treatment of HIV infections. The 'powder in a bottle' approach was used for drug administration for Phase I clinical studies. This new approach consists of compounding the active drug as a suspension or solution at the clinical site immediately before dosing. Prior to clinical use, studies were conducted to determine the compatibility of the drugs with the suspending agent, the recovery of the drugs using the administration procedure and the dissolution profile of the suspensions. The stability of the DPC 961 and 963 in the dosing formulation was followed over a 24-h period using a stability indicating HPLC method. In addition, the dissolution profiles of the suspensions were established for future comparison with solid dosage forms. Although the two drugs have very similar chemical structures, they clearly exhibited different behaviors in liquid/liquid extraction and dissolution experiments. These differences could be related to the physical characteristics of the powders, such as particle size and surface area. The results of the in-use testing of the suspension showed adequate recovery of the drugs from the bottle at two drug levels. The stability of DPC 961 and 963 in the suspending agent was sufficient for constitution and administration of the suspensions at the clinical site.

Anti-HIV Agents↗

PubMed2000

NADPH-diaphorase activity and nitric oxide synthase activity in the kidney of the clawed frog, Xenopus laevis.

Nitric oxide (NO) may play a central role in controlling renal hemodynamics and renal salt excretion. Thus, several investigations focused on localization and function of nitric oxide synthase (NOS) isoforms in the mammalian kidney. Although studies of amphibians have contributed significantly to the elucidation of renal physiology, NOS has not been investigated in the amphibian kidney. Therefore, we characterized NOS and reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase biochemically and, furthermore, visualized putative NO-producing cells in the kidney of the clawed frog, Xenopus laevis. Our results indicate that NADPH-diaphorase activity correlates with NOS activity. Both enzyme activities eluted at 225 mM NaCl on a diethylaminoethanol anion exchange column and had an apparent molecular weight of 235 kDa, as estimated on an S-300 Sephacryl column. In addition, these enzymes were sensitive to Ca2+ and NADPH, but insensitive to calmodulin antagonists (trifluoperazine, W-13) or omission of calmodulin from the reaction medium. The molecular identity of NOS in Xenopus kidney extract was estimated using polymerase chain reaction. Primers to Xenopus neuronal NOS hybridized to a transcript in Xenopus kidney homogenate. NADPH-diaphorase histochemistry revealed staining in the neck segment, distal tubules, collecting segment, and peritoneal funnels. NOS-immunoreactive material was visualized in distal tubules. These results indicate that Xenopus kidney contains at least neuronal NOS, but may contain an additional NOS isoform, which is less calmodulin sensitive.

Animals↗