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Biomedical subjects

Ping Wu

Publications and source records attributed to Ping Wu.

At least 145 records · Page 8Linked to original sources
PubMed2003

[A study on training method for increasing adaptability to blood redistribution in human].

OBJECTIVE: To verify validity of the increase in adaptability of blood redistribution in human body with repeated body position change training and to find preferable training method for increasing astronaut's adaptability of blood redistribution. METHOD: Twelve subjects were randomly divided into group A and B. Six subjects in each group were trained with mode A and B repeated position change (9 times in 11 d) respectively. Their head-down tilt (HDT -30 degrees/30 min) tolerance and orthostatic tolerance were determined before and after training to verify training effects. RESULT: 1) Two kinds of repeated body position change training modes increased all subjects' HDT tolerance. Compared with pre-training, during HDT test subjects' symptom scores in group B were significantly lower than those in group A (P<0.05) and after training decreasing magnitude of heart rate in group B increased significantly (P<0.01). Then mode B to be preferable training method in increasing HDT tolerance was suggested. 2) Two kinds of training modes improved all subjects' orthostatic tolerance. Compared with pre-training, during orthostatic tolerance test increasing magnitude of mean arterial blood pressure in group B increased significantly (P<0.05) and a trend of increasing magnitude of heart rate in group B was appeared smaller than in group A (P<0.10). Mode B to be preferable training method in increasing orthostatic tolerance was suggested too. CONCLUSION: Repeated body position change training could increase adaptability to blood redistribution in human body. Mode B was preferable training method and would be hopeful to be used in astronaut training.

Astronauts↗
PubMed2003

[Application of Ac/Ds transposon system to genetate marker gene free transgenic plants in rice].

It is critical to generate marker gene free transgenic plants for retransformating or eliminating the potential harmfulness of marker gene and its product. In this study, Ac/Ds transposon system was developed for removal of hpt selection marker gene to obtain marker-free transgenic plants in rice ( Oryza sativa L.). Ds element containing the interesting gene bar was constructed next to the selection marker gene hpt to get Ds-T-DNA. Rice plants were transformed by Agrobacterium tumefaciens EHA105 containing Ac-T-DNA and Ds-T-DNA respectively. Rice plant containing single copy Ac-T-DNA was crossed with plant containing single copy Ds-T-DNA to obtain the F1 plant containing both Ac and Ds elements. F1 plant was self-crossed to produce F2 progeny in which T-DNA insert and transposed Ds element segregated independently. Two plants contained Ds element but no hpt marker gene in total 100 F2 plants. The result indicated that Ac/Ds transposon system could be used as a vector system for generating marker gene free transgenic plants in rice.

Agrobacterium tumefaciens↗
PubMed2002

The morphogenesis of feathers.

Feathers are highly ordered, hierarchical branched structures that confer birds with the ability of flight. Discoveries of fossilized dinosaurs in China bearing 'feather-like' structures have prompted interest in the origin and evolution of feathers. However, there is uncertainty about whether the irregularly branched integumentary fibres on dinosaurs such as Sinornithosaurus are truly feathers, and whether an integumentary appendage with a major central shaft and notched edges is a non-avian feather or a proto-feather. Here, we use a developmental approach to analyse molecular mechanisms in feather-branching morphogenesis. We have used the replication-competent avian sarcoma retrovirus to deliver exogenous genes to regenerating flight feather follicles of chickens. We show that the antagonistic balance between noggin and bone morphogenetic protein 4 (BMP4) has a critical role in feather branching, with BMP4 promoting rachis formation and barb fusion, and noggin enhancing rachis and barb branching. Furthermore, we show that sonic hedgehog (Shh) is essential for inducing apoptosis of the marginal plate epithelia, which results in spaces between barbs. Our analyses identify the molecular pathways underlying the topological transformation of feathers from cylindrical epithelia to the hierarchical branched structures, and provide insights on the possible developmental mechanisms in the evolution of feather forms.

Animals↗
PubMed2002

Identification of genes enriched in rice roots of the local nitrate treatment and their expression patterns in split-root treatment.

To identify nitrate-induced genes in rice roots, a nitrate-induced root subtracted library was constructed using the suppression subtractive hybridization (SSH) method and a split-root experiment. Based on forward and reverse screening, 37 known genes and 55 novel genes were identified to be up-regulated in nitrate-supplied side roots. The known genes are involved in nitrogen (N) uptake and assimilation, sugar transport and organic acid metabolism, signal transduction, protein synthesis and degradation, plant resistance, hormone metabolism and cell division. Most of these genes were stronger up-regulated in nitrate-supplied than in nitrate-deficient side roots, which suggests that nitrate may regulate expression of these genes. Expression pattern analysis also revealed that a fast cycle of assimilated N metabolites occurred between root and shoot. Transcriptions of some nitrate-induced genes were also up-regulated in nitrate-deficient side roots, which indicates that nitrate and/or in coordinating with N metabolites from shoots, regulate the transcription of many genes. The enhancement of carbon (C) source partition, the expressions of genes for signal transduction and transcription regulation, auxin transport and ethylene synthesis, and cyclin-dependent kinases may be responsible for the stimulated lateral root growth by nitrate.

Adaptation, Physiological↗
PubMed2002

Prostate-specific antigen and other prostate-derived proteases cleave IGFBP-3, but prostate cancer is not associated with proteolytically cleaved circulating IGFBP-3.

BACKGROUND: Proteolysis of insulin-like growth factor-binding proteins (IGFBPs) may increase IGF-mediated growth stimulation and development of cancer in the organs producing large amounts of proteases, such as the prostate. METHODS: We studied proteolysis of IGFBP-3 by three prostate-derived proteases, namely prostate specific antigen (PSA), human kallikrein 2 (hK2), and trypsin, and also by native seminal plasma. Cleavage of 125I-IGFBP-3 was studied by SDS-PAGE and autoradiography. We also used two different sandwich-type IGFBP-3 immunoassays, called "intact" and "total" IGFBP-3 assays. These assays differ in their capacity to recognize proteolytically degraded IGFBP-3. RESULTS: HK2, PSA, and trypsin all cleaved IGFBP-3 at the concentrations normally present in seminal plasma. The IGFBP-3 cleavage by seminal plasma was inhibited by ZnCl2, which strongly inhibits hK2 and PSA, but not by a specific trypsin inhibitor. The IGFBP-3 fragments resulting from proteolytic cleavage by PSA, hK2, or trypsin were undetectable in the "intact IGFBP-3 assay," whereas the "total IGFBP-3 assay" also detected the proteolytic fragments. No increased fragmentation of IGFBP-3 was found in serum of 659 men with elevated PSA concentrations, of whom 178 had a proven prostate cancer. Furthermore, the IGFBP-3 levels were not associated with the PSA concentrations. CONCLUSIONS: These results show that, while seminal plasma and prostate-derived proteases can cleave IGFBP-3, in patients with prostate cancer the circulating IGFBP-3 is not significantly proteolyzed by either PSA, hK2, or trypsin.

Cell Division↗
PubMed2002

Co-localization of junction-associated proteins of the human blood--aqueous barrier: occludin, ZO-1 and F-actin.

Recent studies in mouse and rabbit eyes have begun to identify the molecular constituents of tight and adherens junctions that represent the structural equivalent of the blood--aqueous barrier (BAB). These species are commonly used as experimental models to examine the pathobiology of anterior uveitis, an inflammatory condition in which the junctions of the BAB are compromised. Because it was unclear whether major molecular elements of the junctions in these species were the same as those in humans, the goal of this study was to determine if the junction related proteins ZO-1 and occludin are present in normal human ciliary epithelium and iridial vascular endothelium. To determine their presence, sections of human anterior uvea were probed in 14 normal, human, eyebank eyes immunolabelled with antibodies to ZO-1, and occludin, and confocal microscopy was used to examine them. Phalloidin staining for F-actin was also assessed. ZO-1 and occludin were both localized along the apico-lateral surfaces of the non-pigmented ciliary epithelium and the interendothelial clefts of iris blood vessels. In both locations, the distribution of occludin was more focal than seen for ZO-1. ZO-1 was also found along the apical surfaces between the pigmented and non-pigmented ciliary epithelial cell layers. The distribution of these proteins supports the notion that occludin is more specifically associated with tight junctions than is ZO-1 in the normal human BAB. No change in this distribution was found with increasing age. These data are consistent with findings reported previously in rabbit ciliary epithelium and iridial vascular endothelium, indicating the relevance of experimental induced uveitis studies in rabbit, as a model of BAB breakdown in human uveitis.

Actins↗
PubMed2002

A spatial impulse response based method for determining effective geometrical parameters for spherically focused transducers.

This paper proposes a novel method for determining effective geometrical parameters (GPs) of spherically focused transducer. Theoretical basis of the method is the spatial impulse response method (SIRM) that is a powerful tool to calculate transient fields from a piston-like transducer. Experimentally, the method is implemented by measuring arrival times of the pulse signals (either transmission or pulse echo signals) and using them to determine the time intervals between the direct and edge wave pulses. Since the time intervals for a given measurement position depend on the transducer's GPs, then the effective GPs can be obtained. The measurements are carried out in the near-field so that the time intervals can be resolved. The proposed method has been applied to a spherically focused transducer operating in pulse echo mode. The results have shown that the effective GPs used in the SIRM give a closer agreement between the theory and the measurements than the nominal GPs. The method is best suited for characterizing broadband transducers with short pulse excitations. With certain modification it can be also applied to narrowband transducers. The method can be also applied to transducers of other shapes, e.g., planar circle, and planar or curved rectangle provided the piston approximation is appropriate.

Journal Article↗
PubMed2002

Region-specific generation of cholinergic neurons from fetal human neural stem cells grafted in adult rat.

Pluripotent or multipotent stem cells isolated from human embryos or adult central nervous system (CNS) may provide new neurons to ameliorate neural disorders. A major obstacle, however, is that the majority of such cells do not differentiate into neurons when grafted into non-neurogenic areas of the adult CNS. Here we report a new in vitro priming procedure that generates a nearly pure population of neurons from fetal human neural stem cells (hNSCs) transplanted into adult rat CNS. Furthermore, the grafted cells differentiated by acquiring a cholinergic phenotype in a region-specific manner. This technology may advance stem cell-based therapy to replace lost neurons in neural injury or neurodegenerative disorders.

Acetylcholine↗
PubMed2002

Factors associated with adolescent utilization of alcohol treatment services.

OBJECTIVE: This study examined factors associated with adolescents' use of alcohol treatment services. METHOD: Data on adolescents (aged 12-17) from the 1994 National Household Survey on Drug Abuse (NHSDA, N = 4,698), a large representative sample of the U.S. population, were used in this study. Information obtained from the survey included adolescent alcohol use, drinking patterns, alcohol abuse/dependent problems, and service use for alcohol-related problems. In addition, socio- demographics, health insurance, mental and behavioral problems, and other drug use were also included in the analysis. RESULTS: The findings indicate that many adolescents with alcohol problems did not receive treatment. White adolescents were more likely to receive alcohol treatment services than nonwhites. Among alcohol-related problems, alcohol causing problems at home, school, or other settings predicted entry into alcohol treatment. Drug use and poor health status were also associated with receiving alcohol treatment services. CONCLUSIONS: This study calls for an improved service delivery system to meet service needs of adolescents with alcohol-related problems, especially among minorities, and those with alcohol-related problems but without yet experiencing significant negative social consequences.

Adolescent↗
PubMed2002

[Developmental genetic analysis for transparency of rice (Oryza sativa L.) at different environments].

The developmental behavior of gene expression for transparency of rice (TR) was analyzed from two-year experimental data at different filling stages by using both conditional and unconditional analysis methods for quantitative traits of seeds in cereal crops. It was revealed that the gene expression was most active for the performance of TR at the middle and late filling stages (8-21 d after flowering). The differences of expression at different environments for triploid endosperm nuclear genes, cytoplasmic genes and diploid maternal plant nuclear genes were found for the performance of TR. The phenomena of which some genetic effects were spasmodically expressible were detected among filling stages of rice. Because of the higher additive and cytoplasmic effects along with their interaction effects for TR at the filling stages, the better improving effects for this trait could be expected by selection in rice breeding. Some parents such as Zhenan 3 and 1391 were better than others for improving TR.

Environment↗
PubMed2002

[Application of lower body negative pressure (LBNP) in aerospace medicine].

Effects of LBNP is similar to that produced by gravitational force, especially as a stress factor on the cardiovascular system as has been concerned in the area of aerospace medicine. This paper described experimental equipment, methods and physiological effects of LBNP, especially its application in the area of aerospace medicine. Several aspects for future research were put forward.

Acceleration↗
PubMed2002

Epitope mapping of antibodies against prostate-specific antigen with use of peptide libraries.

BACKGROUND: Prostate-specific antigen (PSA) is the most important marker for prostate cancer, but PSA concentrations determined by various assays can differ significantly because of differences in specificity of the antibodies used. To identify epitopes recognized by various monoclonal antibodies (MAbs) to PSA, we have isolated peptides that react with the paratopes of these. METHODS: Six anti-PSA MAbs representing three major epitope groups were screened with five cyclic phage display peptide libraries. After selection, the peptide sequences were determined by sequencing of the relevant part of viral DNA. Binding of the phage peptides to the MAbs was monitored by immunoassay. RESULTS: For each MAb, several paratope-binding peptides with distinct sequence motifs were identified, but only approximately 10% showed similarity with the PSA sequence. Some of these correctly predicted the location of the epitopes. By sequential panning of the library with two closely related MAbs, we identified peptides reacting equally with both MAbs. When analyzed against a large panel of PSA MAbs, the peptides generally showed restricted specificity toward the MAb used for selection, but some peptides bound to several related MAbs. CONCLUSIONS: Most of the cyclic peptides selected with PSA MAbs are specific for the MAb used for selection and do not resemble any sequence on the antigen. Peptides reactive with two MAbs recognizing the same epitope can be obtained by sequential panning. This method can be used to predict the location of some epitopes, but additional methods are needed to confirm the result.

Amino Acid Sequence↗
PubMed2002

[Study on hereditary toxicity of bass wood dust].

OBJECTIVE: To explore the genotoxicity of bass wood dust. METHODS: Micronucleus frequency in peripheral lymphocytes of workers exposed to bass wood dust in a match factory were examined, solution of bass wood dust emmersion was prepared and the effect on micronucleus frequency in poly-dyeing red blood cell of mice's sternum marrow was also detected. Single cell gel electrophoresis assay was used to detect DNA damage in liver cell, the level of oxygen free radical, lipid peroxidation(MDA) in the liver and the activity of superoxide dismutase(SOD) in red blood cells were also studied. RESULTS: The positive frequency of micronucleus in bass wood-exposed workers with different length of service (0-, 5-, > or = 10 a) were 50.0%, 51.9%, 50.0% respectively, significantly higher (P < 0.01) than that of the control group(4.5%). A dose-effect relationship could also be found in the mice's micronucleus frequency study(r = 0.78, P < 0.01). The activities of SOD[(10.98 +/- 5.74), (15.70 +/- 7.54), (29.63 +/- 14.97) microgram/g Hb] were significantly lower than that of control group[(35.80 +/- 12.92) microgram/g Hb], and the level of MDA[(4.93 +/- 0.90), (4.61 +/- 1.06), (4.33 +/- 0.69) mmol/g liver] were significantly higher than that of the control group[(2.51 +/- 0.34) mmol/g liver]. Single cell gel electrophoresis study showed DNA strand breaks increased with the dose increase and the level of oxygen free radical also increased with the dose increase. CONCLUSION: Bass wood dust may have certain degree of genotoxicity.

Animals↗
PubMed1998

Child outpatient mental health service use: why doesn't insurance matter?

BACKGROUND: Several recent studies of child outpatient mental health service use in the US have shown that having private insurance has no effect on the propensity to use services. Some studies also find that public coverage has no beneficial effect relative to no insurance. AIMS: This study explores several potential explanations, including inadequate measurement of mental health status, bandwagon effects, unobservable heterogeneity and public sector substitution for private services, for the lack of an effect of private insurance on service use. METHODS: We use secondary analysis of data from the three mainland US sites of NIMH's 1992 field trial of the Cooperative Agreement for Methodological Research for Multi-Site Surveys of Mental Disorders in Child and Adolescent Populations (MECA) Study. We examine whether or not a subject used any mental health service, school-based mental health services or outpatient mental health services, and the number of outpatient visits among users. We also examine use of general medical services as a check on our results. We conduct regression analysis; instrumental variables analysis, using instruments based on employment and parental history of mental health problems to identify insurance choice, and bivariate probit analysis to examine multiservice use. RESULTS: We find evidence that children with private health insurance have fewer observable (measured) mental health problems. They also appear to have a lower unobservable (latent) propensity to use mental health services than do children without coverage and those with Medicaid coverage. Unobserved differences in mental health status that relate to insurance choice are found to contribute to the absence of a positive effect for private insurance relative to no coverage in service use regressions. We find no evidence to suggest that differences in attitudes or differences in service availability in children's census tracts of residence explain the non-effect of insurance. Finally, we find that the lack of a difference is not a consequence of substitution of school-based for office-based services. School-based and office-based specialty mental health services are complements rather than substitutes. School-based services are used by the same children who use office-based services, even after controlling for mental health status. DISCUSSION: Our results are consistent with at least two explanations. First, limits on coverage under private insurance may discourage families who anticipate a need for child mental health services from purchasing such insurance. Second, publicly funded services may be readily available substitutes for private services, so that lack of insurance is not a barrier to adequate care. Despite the richness of data in the MECA dataset, cross-sectional data based on epidemiological surveys do not appear to be sufficient to fully understand the surprising result that insurance does not enable access to care. IMPLICATIONS FOR POLICY AND RESEARCH: Limits on coverage under private mental health insurance combined with a relatively extensive system of public mental health coverage have apparently generated a situation where there is no observed advantage to the marginal family of obtaining private mental health insurance coverage. Further research using longitudinal data is needed to better understand the nature of selection in the child mental health insurance market. Further research using better measures of the nature of treatment provided in different settings is needed to better understand how the private and public mental health systems operate.

Journal Article↗
PubMedDate not supplied

Factors associated with adolescents receiving drug treatment: findings from the National Household Survey on Drug Abuse.

This article examines factors associated with adolescents receiving treatment for drug-related problems. Data on adolescents (aged 12-17) from the 1995 and 1996 National Household Survey on Drug Abuse (NHSDA, N = 9133) were used. Information was obtained concerning adolescent drug use, smoking, drinking and related problems, as well as sociodemographics. Many adolescents with drug-related problems did not receive treatment. Among predisposing factors, gender and age were associated with drug treatment. Severity of drug problems and comorbid emotional and health problems also predicted seeking treatment. The results call for an improved service delivery system. Screening for drug problems in primary care settings, at school, and in mental health programs will help in the early identification and treatment of drug use disorders in youth.

Adolescent↗