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Biomedical subjects

Y Du

Publications and source records attributed to Y Du.

At least 55 records · Page 3Linked to original sources
PubMed2001

Interleukin-11 up-regulates survivin expression in endothelial cells through a signal transducer and activator of transcription-3 pathway.

Interleukin-11 (IL-11) reduces injury both in vivo and in vitro, but the mechanisms are unknown. Stimulation of serum- and growth factor-deprived HUVEC with IL-11 increased survivin mRNA and protein expression levels in a dose-dependent manner, with maximal induction at 50 to 100 ng/ml of IL-11. Survivin mRNA expression peaked after 3 to 6 hours of IL-11 treatment and decreased by 24 hours. Survivin protein expression was maximal at 6 hours of treatment and remained elevated through 24 hours. Survivin induction may be mediated by activation of protein kinase B/Akt, but IL-11 failed to activate this pathway in HUVEC. IL-11 did activate signal transducer and activator of transcription (STAT)-3 and IL-11 failed to induce survivin expression in HUVEC transduced with a dominant-negative STAT3 mutant, whereas control-transduced HUVEC responded normally. An IL-11 transgene caused increased survivin mRNA expression in mice compared with control littermates. Intradermal injection of IL-11 (500 ng) into human skin xenografts on immunodeficient mice up-regulated survivin protein in microvascular endothelium and epithelial keratinocytes. We conclude that IL-11 induces expression of survivin, an antiapoptotic protein, in vitro and in vivo, and identify STAT3 as a critical mediator of this response.

DNA-Binding Proteins↗
PubMed2001

Transfer of recombinant human granulocyte colony stimulating factor (rhG-CSF) from the maternal to the fetal circulation is not dependent upon a functional G-CSF-receptor.

Administration of granulocyte colony stimulating factor (G-CSF), a haematopoietic growth factor, to pregnant rats increases neutrophil production in the pups. The mechanism for the placental transfer is unknown, but it has been speculated to involve the placental G-CSF receptor (G-CSFR). The purpose of this study was to test that hypothesis. Pregnant mice were treated with a single subcutaneous dose of 50 microg/kg recombinant human G-CSF (rhG-CSF). Mice with an intact G-CSFR ("wild type", WT) and those with a homozygous deletion in the G-CSFR gene (G-CSFR deficient, "knock-out", KO) were studied. At intervals after injection, fetuses were delivered and maternal blood, amniotic fluid (AF) and fetal blood collected. G-CSF concentrations were measured using an enzyme linked immunosorbent assay specific for human G-CSF. Thirty minutes after injection, G-CSF was measurable in the AF (167+/-50 versus 445+/-217 pg/ml, mean+/-sem, WT versus KO) and fetal plasma (774+/-673 versus 427+/-121 pg/ml, WT versus KO). Peak concentrations occurred 2 h after injection in WT dams (572 542+/-41 262 pg/ml) and 4 h in KO dams (616 100+/-96 300 pg/ml). Therefore, in mice, a functional G-CSFR is not essential for the transfer of rhG-CSF from pregnant dams to their fetuses.

Amniotic Fluid↗
PubMed2001

Optical properties of porcine skin dermis between 900 nm and 1500 nm.

The weak absorption of shortwave infrared light by skin tissues between 700 and 1500 nm offers an important window for diagnosis by optical means. The strong scattering of shortwave infrared light by the skin, however, presents a challenge to the modelling of light propagation through the skin and the understanding of skin optics. We have measured the collimated and diffuse transmittance and diffuse reflectance of porcine skin dermis samples within 30 h post-mortem. Monte Carlo simulations have been performed to inversely determine the absorption coefficient, scattering coefficient and anisotropy factor of the dermis samples in the spectral range from 900 to 1500 nm. We further analyse the sensitivity of the values of the parameters to the experimental errors and inverse calculation procedures. The state of the cellular integrity of the skin samples following optical measurements was verified using transmission electron microscopy. These results were correlated to study post-mortem effects on the in vitro optical properties of porcine dermis. We concluded that for samples stored within crushed ice for up to 30 h post-mortem the wavelength dependence of optical properties of the dermis remains unchanged while the values of the parameters vary moderately due to modification of the water content of the tissue.

Animals↗
PubMed2001

Aux1p/Swa2p is required for cortical endoplasmic reticulum inheritance in Saccharomyces cerevisiae.

In the yeast Saccharomyces cerevisiae, the endoplasmic reticulum (ER) is found at the periphery of the cell and around the nucleus. The segregation of ER through the mother-bud neck may occur by more than one mechanism because perinuclear, but not peripheral ER, requires microtubules for this event. To identify genes whose products are required for cortical ER inheritance, we have used a Tn3-based transposon library to mutagenize cells expressing a green fluorescent protein-tagged ER marker protein (Hmg1p). This approach has revealed that AUX1/SWA2 plays a role in ER inheritance. The COOH terminus of Aux1p/Swa2p contains a J-domain that is highly related to the J-domain of auxilin, which stimulates the uncoating of clathrin-coated vesicles. Deletion of the J-domain of Aux1p/Swa2p leads to vacuole fragmentation and membrane accumulation but does not affect the migration of peripheral ER into daughter cells. These findings suggest that Aux1p/Swa2p may be a bifunctional protein with roles in membrane traffic and cortical ER inheritance. In support of this hypothesis, we find that Aux1p/Swa2p localizes to ER membranes.

ADP-Ribosylation Factor 1↗
PubMed2001

[Studies on mimotopes of hepatitis C virus E1 protein].

OBJECTIVE: To study the B-cell epitope of E1 protein of hepatitis C virus. METHODS: By induction of IPTG, the E.coli M15 strains harboring the pQE30-HCVe118 expressed truncated C-terminal HCV E1 protein (Pte1). The proteins were purified with preparative electrophoreses system, which captured anti-E1 IgG in HCV (+) sera. By applying the antibodies as selective molecular 12 mers random peptide libraries were panned, and positive clones were obtained by ELISA. Amino acid sequences of display peptide were compared with that of HCV E1 protein. RESULTS: The purified HCV E1 proteins could react specifically with partly anti-HCV sera by ELISA. Among 10 phage display peptides, 6, 6, 2 were the most homologous to HCV E1 protein at position 320-336aa, 251-263aa, 225-248, respectively. CONCLUSIONS: There exist multiple B-cell epitopes in HCV E1 protein. At least one preponderant epitope is mapped at residues 320-336 of HCV E1 protein.

Amino Acid Motifs↗
PubMed2001

Co- and multimedication in users of ASA and vitamin E drugs in the Federal Republic of Germany. Results of the Federal Health Surveys 1984-1999.

OBJECTIVE: Because ASA- and vitamin E-drugs belong to the most used OTC-medications and adverse drug reactions are depending on the quantity and type of comedication we describe the pattern of usage for ASA- and vitamin E-drugs along with the total drug consumption in Germany. STUDY POPULATION, MATERIAL AND METHODS: Study participants (n = 22.560) were screened in five German health surveys (1984-1999). Total drug usage was monitored with a standardized questionnaire. Blood and serum samples were examined for clinical chemistry and hematological data as well as for selected active substances of drugs. The tocopherols and salicylic acid as the main metabolite of ASA were measured by HPLC in serum samples. RESULTS: The incidence of OTC-drug usage is high in our population. The salicylic acid concentration in the serum samples depends clearly on the reason of usage and remains fairly stable for analgesic use but decreases steadily from 1984 to 1999 for use as antiplatelet drug due to formulations with lower amount of ASA/tablet. The serum concentration of alpha-tocopherol was steadily increasing in users of vitamin E-drugs as well as in no-drug-users. CONCLUSION: Because the frequency of comedication is very high, the risk of adverse drug reactions seems to be a problem that should be considered more seriously by physicians.

Adolescent↗
PubMed2001

[Water distribution and microclimatic effects of sprinkler irrigation on spring wheat field].

Measurements of sprinkler irrigation on spring wheat field indicated that spring wheat canopy could intercept water by 25-30%, and compared with that above canopy in first milking period, the uniformity coefficient below canopy could be increased by 7-9%. Floating and evaporation loss of sprinkler irrigation water could reach 20-25% of the total. In addition, sprinkler irrigation on spring wheat field could decrease air and soil temperature, and increase air actual vapor pressure and relative humidity, which played a definite role in restraining crop transpiration.

Microclimate↗
PubMed2001

[Clinical application of the reversed digital arteial island flap with digital wein and digital dorsal nerve anastomosis].

OBJECTIVE: To introduce clinical application of the reversed digital arteial island flap with digital wein and digital dorsal nerve anastomosis to repair digital soft tissue defect. METHODS: Since 1999, 10 cases involving 14 digital defects associated with exposure of bone or tendon were treated by using the reversed digital arterial island flap with digital vein and digital dorsal cutaneous nerves anastomosis. RESULTS: All the flaps were 100% survived and the result is satisfactory. CONCLUSIONS: The reversed digital arterial island flap with anastomosing the digital vein and dorsa digita nerve is a safe, and simple technique, which can maintain the finger's normal appearance and reduce the incidence of venous crisis and improve the survival rate of the flap.

Adolescent↗
PubMed2001

[A survey of oral health status of the elderly individuals in Chengdu of China].

OBJECTIVE: The aim of this survey is to investigate the oral health status of the oldsters over 65-year-old in Chengdu of China. METHODS: The oral health status, including oral hygiene, caries, periodontal diseases and the tooth loss of 468 elderly individuals over 65 years old were surveyed and analyzed. RESULTS: It was found that all these older individuals brushed their teeth everyday, but most of them had tooth decay, gingivitis and periodontitis. About 7.47% of them were edentulous, and 2.56% of them were half edentulous. The masticatory ability of most of them declined and the chewing ability of them was low. CONCLUSION: The oral health status of these elderly individuals in Chengdu is poor. It is therefore necessary to improve the health status of this population.

Aged↗
PubMed2000

A story: unpaired adenosine bases in ribosomal RNAs.

In 1985 an analysis of the Escherichia coli 16 S rRNA covariation-based structure model revealed a strong bias for unpaired adenosines. The same analysis revealed that the majority of the G, C, and U bases were paired. These biases are (now) consistent with the high percentage of unpaired adenosine nucleotides in several structure motifs. An analysis of a larger set of bacterial comparative 16 S and 23 S rRNA structure models has substantiated this initial finding and revealed new biases in the distribution of adenosine nucleotides in loop regions. The majority of the adenosine nucleotides are unpaired, while the majority of the G, C, and U bases are paired in the covariation-based structure model. The unpaired adenosine nucleotides predominate in the middle and at the 3' end of loops, and are the second most frequent nucleotide type at the 5' end of loops (G is the most common nucleotide). There are additional biases for unpaired adenosine nucleotides at the 3' end of loops and adjacent to a G at the 5' end of the helix. The most prevalent consecutive nucleotides are GG, GA, AG, and AA. A total of 70 % of the GG sequences are within helices, while more than 70 % of the AA sequences are unpaired. Nearly 50 % of the GA sequences are unpaired, and approximately one-third of the AG sequences are within helices while another third are at the 3' loop.5' helix junction. Unpaired positions with an adenosine nucleotide in more than 50 % of the sequences at the 3' end of 16 S and 23 S rRNA loops were identified and arranged into the A-motif categories XAZ, AAZ, XAG, AAG, and AAG:U, where G or Z is paired, G:U is a base-pair, and X is not an A and Z is not a G in more than 50 % of the sequences. These sequence motifs were associated with several structural motifs, such as adenosine platforms, E and E-like loops, A:A and A:G pairings at the end of helices, G:A tandem base-pairs, GNRA tetraloop hairpins, and U-turns.

Adenosine↗
PubMed2000

An efficient and concise regioselective synthesis of alpha-(1 --> 5)-linked L-arabinofuranosyl oligosaccharides.

A series of alpha-(1 --> 5)-linked L-arabinofuranosyl di-, tetra-, hexa- and octameric derivatives were synthesized efficiently. The process was carried out in a regio- and stereoselective manner using perbenzoylated arabinofuranosyl trichloroacetimidates as glycosyl donors and unprotected or partially protected arabinofuranosides as glycosyl acceptors in the presence of a catalytic amount of trimethylsilyl trifluoromethanesulfonate (TMSOTf).

Arabinose↗
PubMed2000

Association of an interleukin 1 alpha polymorphism with Alzheimer's disease.

BACKGROUND: Retrospective epidemiologic studies suggest that individuals exposed to anti-inflammatory agents such as nonsteroidal anti-inflammatory drugs have a lower probability of developing AD as well as an older age at onset for the illness. Neuroinflammation may play an important role in the pathogenesis of AD. Interleukin 1 (IL-1), a potent proinflammatory cytokine, is colocalized immunohistochemically to neuritic plaques, a requisite neuropathologic feature for AD. A polymorphism in the 5'-flanking regulatory region at -889 of the IL-1 alpha gene (a C-to-T transition designated as IL-1A[-889] allele 2) may cause an overexpression of IL-1 alpha, a finding shown to be associated with inflammatory diseases. The IL-1A(-889) allele 2 polymorphism may be associated with AD pathogenesis. METHODS: A total of 259 patients with AD and 192 nondemented control subjects were included from two different centers (Indianapolis, IN, and Munich, Germany). Genotyping for APOE alleles and IL-1A(-889) allele 2 was performed by PCR-based amplification followed by restrictive endonuclease digestion. Statistical analyses were conducted by center-, gender group-, and age group-stratified Mantel-Haenszel odds ratios, CI, and p values. RESULTS: The allele frequency of IL-1A(-889) allele 2 was 46% in clinically diagnosed patients with probable AD versus 34% in control subjects from the combined centers. CONCLUSION: The authors found an increased risk for AD with an estimated Mantel-Haenszel odds ratio of 1.68 (95% CI 1.1 to 2.6; p = 0.022) for heterozygous carriers and 7.2 (95% CI 2.0 to 24.5; p = 0.003) for individuals homozygous for IL-1A(-889) allele 2. They found no evidence for an interaction between the IL-1A and the apoE epsilon 4 polymorphisms (carriers and homozygotes), age, or gender with regard to conferred risk. The data strongly support an association between the IL-1A(-889) allele 2, especially in homozygotes, and later-onset AD.

Aged↗
PubMed2000

Suppressing wall turbulence by means of a transverse traveling wave

Direct numerical simulations of wall-bounded flow reveal that turbulence production can be suppressed by a transverse traveling wave. Flow visualizations show that the near-wall streaks are eliminated, in contrast to other turbulence-control techniques, leading to a large shear stress reduction. The traveling wave can be induced by a spanwise force that is confined within the viscous sublayer; it has its maximum at the wall and decays exponentially away from it. We demonstrate the application of this approach in salt water, using arrays of electromagnetic tiles that produce the required traveling wave excitation at a high efficiency.

Journal Article↗
PubMed2000

Inhibition of neuraminidase with neuraminic acid C-glycosides.

Neuraminic (sialic) acid based alpha-C-glycosides have been synthesized and their inhibitory activity towards bacterial neuraminidase (sialidase) was examined. While some C-glycosides were found to be potent inhibitors (Ki 15-30 microM) of this neuraminidase, others afforded no measurable activity. The structure-activity relationship of these C-glycosides is discussed in the context of other previously reported sialidase inhibitors.

Buffers↗
PubMed2000

Numeric chromosomal abnormalities in small lymphocytic and transformed large cell lymphomas detected by fluorescence in situ hybridization of fine-needle aspiration biopsies.

BACKGROUND: Chromosomal abnormalities in some lymphomas are associated with a poor prognosis. Trisomy 12 and deletions of chromosome 13 have been described in small lymphocytic lymphoma (SLL). To determine whether chromosomal aberrations could be detected by fluorescence in situ hybridization (FISH) on fine-needle aspiration biopsies (FNABs), we analyzed and compared specimens from seven patients with SLL and nine patients with a history of SLL that had transformed to large cell lymphoma. METHODS: DNA probes specific to chromosome 12 and the chromosome 13/RB-1 gene locus were used for in situ hybridization on interphase cell nuclei. The cytologic features, ploidy, proliferation index, and conventional cytogenetic analysis findings were correlated with the FISH results. RESULTS: Trisomy 12 was detected in 2 (29%) of the 7 cases of SLL and 2 (22%) of the 9 cases of transformed large cell lymphoma. Deletion of chromosome 13/RB-1 was present in 3 (43%) of 7 cases of SLL and 3 (33%) of 9 cases of transformed large cell lymphoma. CONCLUSIONS: This study showed that interphase cytogenetic analysis by FISH is feasible on FNAB specimens. Trisomy 12 and deletions of chromosome 13/RB-1 were present in some cases of SLL and transformed large cell lymphoma, and the presence of these chromosomal abnormalities did not correlate with transformation to a higher grade of lymphoma.

Adult↗
PubMed2000

Cloning of cytidine triphosphate: phosphocholine cytidylyltransferase mRNA upregulated by a neuropeptide arginine-vasopressin((4-8)) in rat hippocampus.

Neuropeptide arginine-vasopressin((4-8)) (AVP(4-8)) is a metabolite of arginine-vasopressin which has been shown to have potent memory-enhancing activity, facilitate neurite elongation and prolongate cell aging. Identification of differentially expressed genes in hippocampus induced by AVP(4-8) is important for understanding the molecular basis of AVP(4-8) function. Differential display PCR and 5'rapid amplification of cDNA Ends were used. One new full length cDNA encoding rat cytidine triphosphate: phosphocholine cytidylyltransferase (CCT) beta was thus obtained. Northern blot analysis demonstrated that it was upregulated by AVP(4-8) in mature rat hippocampus. The study of tissue distribution with reverse transcription PCR showed that the gene was abundant in brain. Since CCT catalyzes the formation of cytidine diphosphate choline, which was reported to have a beneficial therapeutic effect on Alzheimer's disease, so we speculated that AVP(4-8) may be a potential candidate for treating Alzheimer's disease by upregulating CCT mRNA level.

Amino Acid Sequence↗