Biomedical subjects

Qi Zhang

Publications and source records attributed to Qi Zhang.

At least 163 records · Page 9Linked to original sources

PubMed2004

Trends in the association between obesity and socioeconomic status in U.S. adults: 1971 to 2000.

OBJECTIVE: To study the secular trends in the disparity of obesity across socioeconomic status (SES) groups among U.S. adults. RESEARCH METHODS AND PROCEDURES: We used national representative data collected in the National Health and Nutrition Examination Surveys conducted in 1971 to 1974, 1976 to 1980, 1988 to 1994, and 1999 to 2000 from 28,543 adults 20 to 60 years old. Obesity was defined based on BMI calculated using measured weight and height. Trends in the relationship between obesity and education levels were analyzed controlling for age, gender, and ethnicity. RESULTS: The disparity in obesity across SES (less than high school, high school, and college or above to indicate low, medium, and high SES, respectively) has decreased over the past 3 decades. In National Health and Nutrition Examination Surveys I (1971 to 1974), there was as much as a 50% relative difference in the obesity prevalence across the three groups, but by 1999 to 2000, it decreased to 14%. This trend was more pronounced in women. The trends of diminishing disparities in obesity were also revealed by our logistic and linear regression analyses. The odds ratio converged to 1 from the 1970s to 2000. In most sociodemographic groups, the relationship between BMI and SES (coefficients) has been weakened over time. DISCUSSION: The association between SES and obesity has been weakened over the past 3 decades, when the prevalence of obesity increased dramatically. There are considerable variations in the changes in the associations across gender and ethnic groups. Our findings suggest that individual characteristics are not likely the main cause of the current obesity epidemic in the U.S., whereas social-environmental factors play an important role. Strategies for obesity prevention and management should target all SES groups from a societal perspective.

Adult↗

PubMed2004

Bone marrow stromal cells differentiated into functional Schwann cells in injured rats sciatic nerve.

Bone marrow stromal cells (MSCs) have been shown to differentiate into various lineage cells including neural cells in vitro and in vivo. We therefore examined whether MSCs can differentiate into Schwann cells in injured peripheral nerves, After cultured in vitro, PKH-67-labeled MSCs were injected into the mechanically injured rat sciatic nerves. Three weeks after injection, immunofluorescent examinations were carried out. MSCs had been incorporated around the injured nerves and differentiated into Schwann cells. MSCs had accumulated mainly in the epineurium around the injured nerve. The incorporated cells partially expressed GFAP, S-100, and P75. These results confirmed the possibility that MSCs have the ability to differentiate into Schwann cells, and that injection of MSCs into the injured peripheral nerve would help repair damaged nerve.

Animals↗

PubMed2004

The comparative study on the solution structures of the oxidized bovine microsomal cytochrome b5 and mutant V45H.

A comparative study on the solution structures of bovine microsomal cytochrome b5 (Tb5) and the mutant V45H has been achieved by 1D and 2D 1H-NMR spectroscopy to clarify the differences in the solution conformations between these two proteins. The results reveal that the global folding of the V45H mutant in solution is unchanged, but the subtle changes exist in the orientation of the axial ligand His39, and heme vinyl groups. The side chain of His45 in V45H mutant extends to the outer edge of the heme pocket leaving a cavity at the site originally occupied by the inner methyl group of Val45 residue. In addition, the imidazole ring of axial ligand His39 rotates counterclockwise by approximately 3 degrees around the His-Fe-His axis, and the 4-heme vinyl group turns to the space vacated by the removed side chain due to the mutation. Furthermore, the helix III of the heme pocket undergoes outward displacement, while the linkage between helix II and III is shifted leftward. These observations are not only consistent with the pattern of the pseudocontact shifts of the heme protons, but also well account for the lower stability of V45H mutant against heat and urea.

Amino Acid Substitution↗

PubMed2004

Dietary iron promotes azoxymethane-induced colon tumors in mice.

There is accumulating evidence that high levels of dietary iron may play a role in colon carcinogenesis. We used a mouse model to investigate the impact of elevated dietary iron on incidence of aberrant crypt foci (ACF; a preneoplastic lesion) on tumor formation and on induction of oxidative stress. A/J mice were injected intraperitoneally, once a week for 6 weeks, with the colonotropic carcinogen, azoxymethane (AOM) or saline (vehicle controls). Following AOM or saline treatments, mice were placed on diets of high (3,000 ppm) and low (30 ppm) iron. Mice in each treatment group were sacrificed at 6 and 10 weeks following the final injection with AOM or saline. Colons were removed for subsequent histopathological analysis, which revealed average increases of 4.6 +- 1.3 vs. 10.4 +- 2.5 total tumors at 6 weeks and 30.75 +- 2.7 vs. 41.5 +- 4.4 total tumors at 10 weeks per AOM-treated mouse on low- and high-iron diets, respectively. There were no significant differences in incidence of ACF attributable to iron, although there was a trend toward greater crypt multiplicity per focus in mice on high-iron diets. Notably, no tumors were observed in mice receiving vehicle control injections in place of carcinogen, regardless of the level of dietary iron. These data suggest that iron exerts its effect at the stage of tumor promotion, but is not sufficient to initiate tumor formation. To learn more about mechanisms by which iron promotes tumor growth, colons were assayed for several biomarkers of oxidative stress [BOS; total F2-isoprostanes (F2-IsoPs), 15-F2t-isoprostanes (8-IsoPGF2s), Isofurans (IsoFs), and 8-hydroxyguanosines (8-OH[d]Gs)], as well as iron absorption, programmed cell death, and cellular proliferation. Elevated PCNA and TUNEL staining of the colon epithelium revealed hyperproliferative and apoptotic responses to iron, while no significant differences between iron groups were observed in each of the BOS that were assayed. Our results suggest that, following carcinogen exposure, elevated dietary iron promotes the growth of tumors with altered cellular homeostasis through a mechanism that is independent of oxidative stress.

Animals↗

PubMed2004

Attenuation of okadaic acid-induced hyperphosphorylation of cytoskeletal proteins by heat preconditioning and its possible underlying mechanisms.

An imbalanced phosphorylation system is recognized to be one of the main reasons for Alzheimer-like hyperphosphorylation of cytoskeletal proteins. However, little is known about the strategies rectifying the lesions caused by this disrupted phosphorylation. To search for the means to arrest Alzheimer-like damages and explore the underlying mechanisms, in this study we treated N2a/peuht40 cells with okadaic acid (OA), a specific inhibitor of protein phosphatase-2A (PP-2A) and PP-1, to mimic an Alzheimer-like phosphatase-deficient system and then used heat preconditioning (42 degrees C for 1 hour) to induce the expression of inducible heat shock protein 70 (Hsp70) in the cells. We observed that heat preconditioning arrested OA-induced hyperphosphorylation of neurofilament (NF) protein at SMI34 and SMI33 epitopes as well as hyperphosphorylation of tau at Tau-1 and PHF-1 epitopes. It counteracted OA-induced decrease in PP-2A activity with a concurrent inhibition in constitutive activity of mitogen-activated protein kinases (MAPKs) and cyclic adenosine 5'-monophosphate-dependent protein kinase A (PKA). Conversely, quercetin, a recognized blocker of stress-responsive Hsp70 expression, diminished the effects caused by heat preconditioning. These results suggested that Hsp70 antagonized OA-induced Alzheimer-like NF and tau hyperphosphorylation, and the restoration of PP-2A and inhibition of MAPKs-PKA activity might be part of the underlying mechanisms for the rectification of OA-induced hyperphosphorylation.

Alzheimer Disease↗

PubMed2004

Differentiation of the human mesenchymal stem cells derived from bone marrow and enhancement of cell attachment by fibronectin.

The ability of human mesenchymal stem cells (hMSC) to differentiate into osteoblasts was examined through the use of osteogenic induction medium (MSCOIM) cultures. hMSC first attached to the dish surface and exhibited fibroblast-like spindle shapes, and after proliferation, formed cuboidal shapes. Calcium assays and the use of von Kossa and alizarin red S staining showed that hMSC were capable of mineralization when cultured in MSCOIM. Gene expressions of Cbfa-1 and BMP-4, which are markers for osteogenic differentiation, were also increased during the hMSC differentiation into osteoblasts. When compared to albumin (Alb)-coated dishes, microscopic observation documented enhanced cell attachment and spreading when hMSC were cultured on fibronectin (FN)-coated dishes. Adherent cell numbers also exhibited a greater increase on the FN-coated dishes during earlier culture stages than that seen for the Alb-coated dishes. These findings suggest that hMSC have the capability to differentiate into osteoblasts and that FN can stimulate the attachment and spreading of the hMSC.

Bone Marrow Cells↗

PubMed2004

[A novel method for continuously assessing the spatio-temporal properties of locomotor activity in mice].

OBJECTIVE: To develop a novel method for continuously assessing the spatio-temporal properties of locomotor activity of mice in an open field using a video-tracking system. METHODS: The locomotor tracks in the open field were recorded by video camera within 22 h, and analyzed by AnalyPower1.1 system that we developed recently. Total distance, distances traveled in different zones and their ratios to total distance; total time,times spent in different zones and their ratios to total time were used as indicators to assess the properties of locomotor activity. RESULTS: In free and wakeful state, the locomotor activity of mice presented obvious regional and temporal properties. Mice preferred to stay in home base (food and water zones), and frequently visited the peripheral zones but seldom the center zones within 22 h. On the other hand, mice were most active within the first 1 h, and then their activity obviously decreased. After their activity became stable, the mice showed the obvious circadian variation of the activity as they were more active in the night. CONCLUSION: The novel method we developed in this study can continuously assess the spatio-temporal properties of locomotor activity quantitatively and objectively.

Animals↗

PubMed2004

[A study on urine microglobulin change after interventional therapy of renal artery in patients with coronary heart disease].

OBJECTIVE: To evaluate the urine microglobulin change after interventional therapy in patients with renal artery stenosis. METHODS: According to the results of renal artery angiography, 69 consecutive patients with coronary heart disease were divided into 2 groups, including 44 patients with severe renal artery stenosis RAS (luminal narrowing > 70%, group I) and 25 patients with atherosclerotic lesion in renal artery (luminal narrowing > 50% but < 70%, group II). The urine alpha(1), beta(2)-microglobulin (alpha(1), beta(2)-MG) were measured respectively. The successful procedural rates, rates of complication, serum creatitine and the urine alpha(1), beta(2)-MG 3 months after procedure were also recorded. The acute results and long-term follow-up outcomes were compared between the 2 groups. RESULTS: Urine alpha(1)-MG [(5.2 +/- 2.5) microg/L vs (3.0 +/- 2.7) microg/L, P > 0.001] and beta(2)-MG [(377 +/- 173) microg/L vs (202 +/- 184) microg/L, P > 0.001] were significantly higher in group I than in group II. However, the urine alpha(1)-MG of the 2 groups did not exceed the normal range (<6 microg/L). The urine beta(2)-MG [(237 +/- 187) microg/L vs (377 +/- 173) microg/L, P > 0.01] 3 months after stenting procedure in group I were significantly decreased. There were no significance change in urine alpha(1)-MG in group I and both the microglobulins in group II during follow-up. There was significant difference in improvement of blood pressure between the 2 groups (62.5% vs 9.1%, P > 0.01). As compared with group II, group I patients had more re-admission (22.5% vs 9.1%), renal failure (5% vs 0) and higher mortality (5% vs 0). However, these measurements did not differ significantly. Multivariate analysis revealed that persistent elevation of urine beta(2)-MG was an independent predictor of severe events (including re-admission and renal failure) after renal artery stenting (OR = 3.01, 95% CI 1.01 - 8.95, P = 0.036). CONCLUSIONS: Severe RAS causes damage of tubular reabsorption. Renal artery stenting improves tubular function, but in patients with persistent elevation of beta(2)-MG, the rates of re-admission and renal failure remain high.

Angiography↗

PubMed2004

[Coronary stenting in patients with acute coronary syndrome and renal dysfunction].

OBJECTIVE: To evaluate the immediate and mid-term efficacy of coronary stenting in patients with acute coronary syndrome (ACS) and renal dysfunction. METHODS: Sixty-three ACS patients with renal dysfunction were included (RD group) and 63 contemporaneous ACS patients with normal renal function served as a control group. The clinical characteristics, stenting procedure and follow-up information were compared between the two groups. RESULTS: Patients in the RD group had higher basic serum creatinine levels [(177 +/- 31) micro mol/L vs (98 +/- 21) micro mol/L, P < 0.001], lower left ventricular ejection fraction (0.45 +/- 0.10 vs 0.50 +/- 0.09, P < 0.05) and increased prevalence of multivessel coronary artery disease (84% vs 65%, P < 0.05) as well as > 50% renal artery stenosis (27% vs 8%, P < 0.05). There was no statistical difference in procedural success rate and major adverse cardiac events occurrence during a mean follow up time of 27 months (13% vs 8%, P = 0.38). In the RD group, the mean level of serum creatinine was significantly decreased [(177 +/- 31) micro mol/L vs (147 +/- 11) micro mol/L, P < 0.05] and 9 (69%) patients with renal artery stent implantation had normal creatinine levels during follow-up. CONCLUSIONS: Coronary stenting is a safe and effective therapy for ACS patients complicated with renal dysfunction, two thirds of patients receiving renal stent implantation had normal serum creatinine during follow-up.

Adult↗

PubMed2004

[Relationship between bronchial hyperresponsiveness and the peripheral obstruction in stable asthmatic children].

OBJECTIVE: Asthma is the most common chronic respiratory disease of children. The association between asthma and bronchial hyperresponsiveness (BHR) has been well-demonstrated. The objective of the study was to investigate relationship between the bronchial responsiveness and the peripheral obstruction in stable asthmatic children. METHODS: Thirty-nine children with stable asthma, 28 boys and 11 girls with a mean age of 128 (77 - 197) months, received the bronchial provocation test by the maximal expiratory flow-volume (MEFV) curve measurement. The children were divided into two groups: one with maximal mid-expiratory flow (MMEF) < 80% (n = 15) and the other with MMEF >/= 80% (n = 24). Positive rates of bronchial provocation test were compared between groups of MMEF < 80% and >/= 80% and between the children whose relief duration was </= 12 months (n = 26) and > 12 months (n = 13). Statistical analysis was performed by using Chi-square, rank sum test or t test (SPSS10.0), P values < 0.05 were considered significant. RESULTS: In the 39 stable asthmatic children, 15 (38%) were detected MMEF < 80% and 28 (72%) had BHR. There was no significant difference in BHR between the children with MMEF < 80% and those with MMEF >/= 80% (P > 0.05). There was no significant difference in BHR between the children whose relief duration was </= 12 months and > 12 months (P > 0.05), either. CONCLUSIONS: The stable asthmatic children still had peripheral obstruction and BHR, which indicated the presence of airway inflammation. There was no significant difference in BHR between the children whose relief duration was </= 12 months and > 12 months.

Asthma↗

PubMed2004

Pharmacokinetics of recombinant human basic fibroblast growth factor in rabbits and mice serum and rabbits aqueous humor.

AIM: To study the pharmacokinetics of recombinant human basic fibroblast growth factor (rhbFGF) in rabbits and mice after iv and postocular administration, and the changes of rhbFGF in rabbits aqueous humor after postocular administration. METHODS: After iv or postocular administration three doses of rhbFGF in rabbits and mice, rhbFGF concentration in serum and rabbit aqueous humor was determined by enzyme-linked immunosorbent assay. RESULTS: Serum concentration-time data of rabbits after iv administration of rhbFGF 1, 2, and 4 micro/kg were fitted to bi-exponential equations with half-lives of 0.9, 0.9, and 0.6 min for T1/2alpha and 7, 8, and 4.7 min for T1/2beta. Plasma concentration-time data of mice after iv administration of rhbFGF 2.5, 5 and 10 microg/kg were fitted to bi-exponential equations with half-lives of 0.4, 0.6, and 0.9 min for T1/2alpha and 6, 5, and 7 min for T1/2beta. The AUCs were linearly correlated to doses in both cases (r rabbit=0.997, r mouse=0.999). The serum concentrations of rhbFGF were very low, near to the background after postocular administration of 2 or 5 microg/kg, in both rabbits and mice. The rhbFGF levels in rabbits aqueous humor were higher than control 8 h postdose (P<0.01). CONCLUSION: rhbFGF within the examined doses had a linear pharmacokinetics in rabbits and mice. High concentration of rhbFGF was found in rabbits aqueous humor after postocular administration.

Administration, Topical↗

PubMed2004

[Establishment and characterization of a neural stem cell line (RNSC-FMU 1) from rat brain].

A neural stem cell line (RNSC-FMU 1) from rat brain have been established successfully by isolating and culturing neural stem cells from newborn SD rat brain in vitro with free-serum medium and passaging with mechanical division. The cell line cultured can continuously generate in vitro for long-term and it is 21 months (>100 passages) so far. These cells keep the feature of neural stem cell and normal karyotype. These neural stem cells can be induced to differentiate into neurons, astrocytes and oligodendrocytes. The cells have an extensive self-renewal capacity; its doubling time of proliferation is about 20 h. The cells are also cryopreservable. Tumor formation is not observed in nude mice that explanted with the cells. This cell line is a good tool for research of neural stem cell.

Animals↗

PubMed2004

[Cloning and heterologous expression of a novel delta6 -desaturase gene from Rhizopus arrhizus NK030037].

A 593 bp DNA fragment was amplified from Rhizopus arrhizus NK030037 with degenerate oligonucleotide primers designed based on the sequences information for fungi delta6-fatty acid desaturase genes by RT-PCR and sequenced. Gene specific primers derived from this partial sequence were used for the amplification of the 3'- and 5'-ends of this cDNA by RACE method, and this lead to a full-length cDNA sequence of 1 482 bp was amplified. Sequence analysis showed this cDNA sequence had an open reading frame(ORF) of 1 377 bp coding 458 amino acids of 52 kD. The deduced amino-acid sequence of the ORF showed similarity to those of the above delta6-fatty acid desaturases which comprised the characteristics of membrane-bound desaturases, including three conserved histidine-rich boxes and hydropathy profile. A cytochrome b5-like domain was observed at the N-terminus. The full-length cDNA sequence is a putative novel delta6-fatty acid desaturase gene. To elucidate the function of the protein, two specific primers corresponding to the nucleotide sequences of start and stop codons were used to amplify the coding sequence. The amplified cDNA RAD6 was subcloned into the expression vector pYES2.0 to generate a recombinant plasmid pYRAD6, which was subsequently transformed into Saccharomyces cerevisiae strain INVScl for heterologous expression by lithium acetate method. Grown to logarithmic phase at 30 degrees C, the transformed cells were supplemented with 0.5 mmol/L. Linoleic acid and induced by 2% galactose for a further 48 h of cultivation at 20 degrees. Total fatty acids were extracted from the induced cells and subjected to methyl-esterification. The resultant fatty acid methyl esters(FAME) were analyzed by gas chromatography(GC). A novel peak corresponding to gamma-linolenic acid (GLA) methyl ester standards was detected with the same retention time, which was absent in the cell transformed with empty vector. The percentage of this new fatty acid to total fatty acids was 3.85%. Gas chromatography-mass spectrometry( GC-MS) analysis of this fatty acid methyl derivative demonstrated that the novel peak was GLA methyl ester. These results showed that the transgenic product exhibited delta6-fatty acid desaurase activity, converting LA to GLA specifically.

Amino Acid Sequence↗

PubMed2004

[Pyramiding of senescence-inhibition IPT gene and Xa23 for resistance to bacterial blight in rice (Oryza sativa L.)].

Transgenic lines (GC-1) carrying a senescence-inhibition cheimeric gene, IPT (isopentenyl transferase) gene, CBB23, a isogenic lines carrying Xa23 gene for resistance to bacterial blight, and Hexi15, a commercial cultivar showing high resistance to blast disease, were used as donors to pyramid IPT gene and Xa23 by marker-assisted selection (MAS). Seventeen BC1F1 plants pyramiding Xa23 gene and IPT genes were obtained from three multi-cross combinations. Then, the plants carrying Xa23 and IPT genes were crossed with parental lines of two-line hybrid rice, such as 9311, E32, Pei' ai 64S and W9834S. The progenies were backcrossed the acceptor parents. A total of 17 plants carrying Xa23 and IPT genes were detected by PCR, disease resistance identification and analysis of CTK contents of in the four combinations of "(9311///Hexi15/CBB23// GC-1) x 9311", "(E32///Hexi15/CBB23//GC-1) x E32", "(Pei'ai 64S///Hexi15/CBB23//GC-1) x Pei' ai 64S" and "(GC-1/CBB23//W9834S/Hexi15) x W9834S". These plants showed resistance to blast disease by inoculating test using 21 the lines of Pyricularia grisea from Northern China. Six plants of BC2F1 pyramiding Xa23 and IPT genes were further obtained in the combinations of "[(9311///Hexi15/CBB23//GC-1) x 9311] x 9311", "[(E32///Hexi15/CBB23//GC-1) x E32] x E32". After backcrossed and self-crossed 1 approximately 2nd, the plants pyramiding Xa23 and IPT genes can be used in the program of hybrid rice breeding.

Alkyl and Aryl Transferases↗

PubMed2004

[Differentiation and increase of dendritic cells from umbilical cord blood in vitro].

The aims of this study were to analyze the composition of umbilical cord blood cells (UCBC), to examine the characteristics of dendritic cells (DC) before and after culture, to search the method of differentiation and increase of DC in vitro and to appraise surface antigen from UCBC. Twelve units of umbilical cord blood were collected from May 2002 to September 2002. Peripheral blood mononuclear cells of 9 cases were collected from healthy adult donors. The nature of UCBC was freshly determined and then UCBC were cultured for 1, 2, 3 and 4 weeks with granulocyte-monocyte colony-stimulating factor (GM-CSF), interleukin 3 (IL-3), recombinant human stem cell factor (SCF) and EPO. Method of flow cytometry was used to determine the number of DC and cell surface antigens before and after culture by using monoclonal antibodies. The monoclonal antibodies included CD4, CD8, CD19, CD34, CD38, CD83, CD1a, CD11c and CDw123. The results showed that amounts of CD34+ progenitors in peripheral blood cells were 0.02 x 10(5)/ml, and amounts of CD34+ progenitors in human UCBC were 0.22 x 10(5)/ml. UCBC cultured for 1, 2, 3 and 4 weeks with GM-CSF, IL-3, EPO and SCF were shown to differentiate into CD1a+ CD11c+ CD83+ CDw123+ DC. Numbers of DC from UCBC remarkably generated in 2-4 weeks and then decreased in number. By culture with cytokines DC increased up to (10.6 - 28.2) x 10(5)/ml in actual numbers. It is concluded that the mononuclear cells of UCB are able to differentiate into CD1a+, CD83+, CD11c+ and CDw123+ DC when UCBC are cultured with proper cytokines of GM-CSF, SCF, EPO and IL-3 for 2-4 weeks. These DCs as antigen presenting cells are possibly effective in cancer immunotherapy.

Antigens, CD1↗

PubMed2004

A new furobenzopyranone and other constituents from Anaphalis lactea.

Together with twenty-one known compounds, a new furobenzopyranone was isolated from the whole plant of Anaphalis lactea. Their structures were elucidated by spectroscopic methods MS, IR, UV, NMR, including 2D-NMR techniques. The anti-bacterial activity of compounds 1, 4-6, 14, 15 and the anti-tumor activity of compounds 4-6 were tested.

Anti-Bacterial Agents↗

PubMed2004

Phenylpropanosids, lignans and other constituents from Cremanthodium ellisii.

Together with twenty-six known compounds, a new phenylpropanosid, named cremanthodioside, was isolated from the whole plant of Cremanthodium ellisii Kitam. Their structures were elucidated by spectroscopic methods MS, IR, UV, NMR, including 2D NMR techniques, and by chemical methods. The anti-bacterial activity of compounds 1-6 and the anti-tumor activity of compound 1 were tested.

Acetylation↗

PubMed2004

Sesquiterpenes, lignans and other constituents from Saussurea macrota.

From the methanol extract of the whole plant of Saussurea macrota Franch, 21 compounds were isolated. Their structures were elucidated by spectroscopic methods and X-ray crystallography. Two of them are new: 3alpha-hydroxy-11alphaH-guaia-4(15),10(14)-diene-12,6alpha-olide (1) and 7'-hydroxyiso-lappaol A (11). Compound 2 is reported as a natural compound for the first time. In addition, the compounds 12 and 13 showed significant antitumor activity against Bel-7402 and HO-8910 cells. Some of the compounds exhibited weak antibacterial activity against Staphylococcus aureus, Bacillus subtilis and Escherichia coli.

Antineoplastic Agents, Phytogenic↗