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Biomedical subjects

Y Yang

Publications and source records attributed to Y Yang.

At least 613 records · Page 34Linked to original sources
PubMed1999

A radiation hybrid map of bovine chromosome one.

Radiation hybrid (RH) mapping has proven to be an extremely powerful approach to constructing high density maps of human chromosomes and is experiencing increased use in other animals, including cattle. A 5000 rad bovine whole-genome radiation hybrid panel was recently constructed in order to integrate existing cattle linkage maps with evolutionarily conserved genes and provide high resolution comparative maps relative to humans and mice. We utilized this panel to construct a 19 marker framework map of bovine chromosome 1 (BTA1), which included 8 Type I loci and 11 Type II loci ordered with at least 1000:1 odds. A 35 marker comprehensive map including 15 Type I loci and 20 Type II loci was also produced. Of the 15 Type I loci ordered on the comprehensive map, three are ordered on HSA3 and five are ordered in three blocks on HSA21 on the human cytogenetic maps.

Animals↗
PubMed1999

Protein-protein interactions between native Ro52 and immunoglobulin G heavy chain.

Using a yeast two-hybrid system to search for proteins interacting with Ro52 autoantigen, we identified a novel protein-protein interaction. Two different cDNA clones, which interacted with Ro52 in the yeast two-hybrid system, were identified and isolated from a human B-cell library. Surprisingly, both clones encoded the heavy chain of human IgG1. The expression of both HIS3 and beta-galactosidase reporter genes in yeast suggested that the interaction between Ro52 and IgG occurred in vivo. In vitro studies utilizing recombinant Ro52 and purified immunoglobulins indicated that the interaction was immunoglobulin class and subclass specific. Ro52 interacted with IgG1 and IgG4, but not with IgG2, IgG3, IgA or IgM. Ro52 could also precipitate IgG directly from serum. The identified cDNA clones did not include the variable region of IgG, which suggested a non-classical interaction independent of antibody specificity. We further mapped the domain of Ro52 responsible for this interaction to the C-terminus rfp-like region. In conclusion, our data support an unusual interaction between native Ro52 and IgG. The potential biological significance of this unusual protein-protein interaction is discussed.

Amino Acid Sequence↗
PubMed1999

Generation of enhancer trap lines in Arabidopsis and characterization of expression patterns in the inflorescence.

Eleven thousand, three hundred and seventy enhancer/promoter trap lines in Arabidopsis were generated via T-DNA transformation utilizing the binary vector pD991 that contains a minimal promoter fused to the uidA reporter gene. Overall 31% of the lines generated exhibit a staining pattern in the inflorescence. Flanking DNA has been cloned from 15 lines exhibiting inflorescence staining patterns by either thermal asymmetric interlaced PCR (TAIL-PCR), inverse PCR (IPCR), or partial library construction. Seeds from these lines are available from the ABRC and NASC Arabidopsis stock centers and DNA pools are available from the ABRC.

Arabidopsis↗
PubMed1999

Olanzapine transfer by human placenta.

1. The present study assessed the human transplacental transport of olanzapine, a new antipsychotic drug effective in the treatment of schizophrenia. 2. Using the normal-term placenta perfused single cotyledon system, we show that: (i) 5-14% of labelled olanzapine crosses from the maternal to foetal compartments in 4 h; (ii) transport depends significantly on binding characteristics, especially of albumin; (iii) no oxidative metabolites of olanzapine appear in the placental perfusate over 4 h; and (iv) approximately 17% of olanzapine, on average, is converted to the glucuronide, which is transferred by the placenta at a rate slightly slower than the parent drug.

Antipsychotic Agents↗
PubMed1999

Mouse M290 is the functional homologue of the human mucosal lymphocyte integrin HML-1: antagonism between the integrin ligands E-cadherin and RGD tripeptide.

Human mucosal lymphocyte antigen-1 (HML-1, alphaEbeta7) and E-cadherin, two members of unrelated cell adhesion superfamilies, have evolved to play cooperative roles in gut mucosal immunity. Human E-cadherin is self-ligand mediating intercellular adhesion of epithelial cells, as well as adhesion of intra-epithelial lymphocytes to intestinal enterocytes via an interaction with HML-1. Herein we report that both dimeric and monomeric forms of recombinant mouse E-cadherin-human immunoglobulin Fc chimera self-associate and support attachment of E-cadherin+ mouse colon epithelial cells. Both forms also support the adhesion of mouse MTC-1 T cells via M290, thereby establishing M290 as the functional mouse homologue of HML-1 and revealing that E-cadherin homophilic and heterophilic binding sites are distinct. Adhesion of MTC-1 cells to E-cadherin-Fc was inhibited by arginine-glycine-aspartate (RGD) peptides and vice versa cells bound to immobilized RGD polymer in an M290-dependent fashion, where adhesion was inhibitable with soluble E-cadherin-Fc. Hence, E-cadherin and RGD integrin ligands antagonize cell binding by one another, either by inducing integrin cross-talk or by binding to shared or overlapping sites within M290. Binding of E-cadherin-Fc by HML-1 costimulated the CD3-induced proliferation of purified CD4+ T cells, suggesting that E-cadherin expressed on dendritic cells may play a T cell costimulatory role in addition to facilitating dendritic cell-keratinocyte adhesion.

Amino Acid Sequence↗
PubMed1999

Selected factors influencing self-concept among hospitalized Chinese school-age children with a chronic illness.

A correlational descriptive study was conducted to investigate self-concept and selected influencing factors among hospitalized Chinese school-age children with a chronic illness. The purposive sample was composed of 122 school-age children with chronic illnesses, such as nephrotic syndrome, leukemia, and congenital heart disease, who were admitted to three major teaching hospitals in Shanghai City. The children's medical records, demographic forms, and the Piers-Harris Self-concept Scale (PHSCS) were used to collect the data. Descriptive statistics, and stepwise multiple regression were used to analyze the data utilizing the SPSS program (SPSS Inc, Chicago, IL, USA). The results of this study showed that the majority of hospitalized Chinese school-age children with a chronic illness had at least an average level of self-concept. Academic achievement (grade point average) was a strong predictor of self-concept, as are most of its subconcepts, including social behavior, academic competence, and physical appearance and attributes. Age was a significant predictor of overall self-concept, social behavior, and popularity subconcept. Sex was a significant predictor of self-concept subconcepts such as social behavior, anxiety, and popularity. Duration of illness was a significant predictor of physical appearance and attributes. In addition, the type of illness was a significant predictor of popularity. It can be concluded that the importance of school education should be emphasized by hospital and school nurses for the purpose of helping such children build a positive self-concept concerning their age, sex, academic achievement, type of illness, and duration of illness. Recommendations for further research have been suggested.

Adolescent↗
PubMed1999

Identification of new mutations in the hepatocyte nuclear factor 4alpha gene among families with early onset Type 2 diabetes mellitus.

AIMS: Mutations in hepatocyte nuclear factor (HNF)-4alpha gene located on chromosome 20q have been found to be responsible for the development of early onset Type 2 diabetes mellitus (DM). Through a national campaign, 53 families with autosomal dominant, early onset Type 2 DM (n=654) were assembled to determine the frequency of mutations in the HNF-4alpha gene and their contribution to the development of diabetes. METHODS: Twelve exons and the promoter region of the HNF-4alpha gene were screened in probands of the families by a double gradient, denaturing gradient gel electrophoresis (DG-DGGE) protocol combined with automated bi-directional sequencing of the PCR products of all heterozygous individuals. RESULTS: We detected two new mutations in the HNF-4alpha gene that changed the amino-acid sequence. The first mutation was a Gly-->Ser substitution in codon 115 within a highly conserved DNA binding domain, and all six carriers of this mutation had diabetes and low insulin secretion. The second mutation was an Ile-->Val substitution in codon 454 within the transactivation domain. It was carried by four family members, two of whom also carried a mutation in the HNF-1alpha gene. Of those having only the mutation in HNF-4alpha one had diabetes and the other had normal glucose tolerance and both were obese and hyperinsulinaemic. Thus, it is uncertain that this mutation is responsible for any of the diabetes in this family. CONCLUSION: We have found that mutations in the HNF-4alpha gene account for a small proportion, about 2-4%, of families with early onset, autosomal dominant, Type 2 DM in US Caucasians.

Adolescent↗
PubMed1999

CTCF is essential for up-regulating expression from the amyloid precursor protein promoter during differentiation of primary hippocampal neurons.

The transcriptional mechanism underlying amyloid precursor protein (APP) regulation in primary neurons during development was investigated. We observed an approximately threefold elevation of APP mRNA levels in differentiating rat hippocampal neurons between day 1 and day 7 in culture and in rat brain hippocampi between embryonic day 18 and postnatal day 3. When an APP promoter construct extending to position -2,832 upstream from the main transcriptional start site was transfected into primary rat hippocampal neurons, promoter activity increased from day 1 until reaching a maximum on day 7 in culture. This increase in APP promoter activity was correlated more closely with the time course of expression of the synaptic vesicle protein synaptophysin, an indicator of synaptogenesis, than with neurofilament accumulation, an indicator of neuritogenesis. Transfection of 5' APP promoter deletions and internal block mutations indicated that the CTCF binding domain designated APBbeta was the primary contributor to the increase in APP promoter activity. Furthermore, the binding of transcription factor CTCF to the APBbeta element increased approximately fivefold between day 1 and day 7, whereas the binding of USF to the APBalpha sequence increased only twofold. These results suggest that CTCF is pivotal for the up-regulation of APP expression during synaptogenesis in primary neurons.

Actin Cytoskeleton↗
PubMed1999

Novel experimental model using free radical-induced emesis for surveying anti-emetic compounds from natural sources.

A novel experimental model of free radical-induced emesis for screening anti-emetic compounds from natural sources was established. 2,2'-Azobis(2-amidinopropane) dihydrochloride (AAPH) dissolved in liposome induced emesis in young chickens, and the emesis was prevented by antioxidants including N-(2-mercaptopropionyl)-glycine (MPG), alpha-tocopherol, and L-ascorbic acid. Tropiseton, a serotonin receptor antagonist, also prevented emesis induced by AAPH. Known anti-emetic drugs and anti-emetic principles from natural sources also showed significant retching inhibition in the experiment using this system.

Amidines↗
PubMed1999

Expression of growth hormone and insulin-like growth factor in the immune system of children.

Our objective was to study the effect of the growth hormone--insulin-like growth factor axis on the development of the immune system in children. We used radio receptor analysis, dot blot, in situ hybridization, and immunohistochemical techniques to determine the expression and distribution of growth hormone and growth hormone receptors, insulin-like growth factors, receptors and binding proteins in the thymus, lymph nodes and peripheral blood lymphocytes of children and adults. Our results showed that almost all components of the growth hormone-insulin-like growth factor axis were expressed in immune organs and cells, but the levels of expression varied. Growth hormone, insulin-like growth factor I, and insulin-like growth factor-binding proteins 1-6 were produced by immune cells in autocrine or paracrine ways. The expression of growth hormone receptors on peripheral blood lymphocytes was to be age-related. The growth hormone-insulin-like growth factor axis may help regulate the development and function of the immune system in children.

Adolescent↗
PubMed1999

Characterization of a life-extending mutation in age-2, a new aging gene in Caenorhabditis elegans.

We have generated a life-extending mutation, yw23, in Caenorhabditis elegans. The mutation is in what appears to be a new aging gene, which we have designated age-2. When homozygous, yw23 produces an increase of mean and maximum life span of about 20% over that of the wild-type strain, N2. Strain HG23 [age-2(yw23)] was obtained by screening for longer life spans among 430 lines of nematodes two generations after exposure to the mutagen ethylmethanesulfonate. Strain HG231 [age-2(yw23)] was obtained after a single out-crossing of HG23 to N2. When compared with N2, HG231 exhibits normal motility, slightly higher swimming rates, reduced fertility (especially at higher temperatures), somewhat longer development times, and a slightly larger size at the time of first egg laying. A Gompertz analysis suggests that HG231 extends life span by reducing the initial mortality rate. In genetic crosses, yw23 complements other known aging mutants in C. elegans genes-age-1, daf-2, spe-26, clk-1, clk-2, clk-3, and gro-1. A double-mutant strain, HG284, combining mutations in age-1 and age-2, lives longer than animals with individual mutations in either age-1 or age-2, and exhibits a longer life span at 25 degrees C than at 20 degrees C.

Aging↗
PubMed1999

Biochemical characterization of novel tetrahydrofuranyl 1beta-methylcarbapenems: stability to hydrolysis by renal dehydropeptidases and bacterial beta-lactamases, binding to penicillin binding proteins, and permeability properties.

The biochemical properties of tetrahydrofuranyl (THF) carbapenems, carbapenems with THF substituents, were evaluated with respect to enzyme stability, binding to penicillin-binding proteins (PBPs), and penetration into gram-negative organisms. THF carbapenems showed increased stability to hog renal dehydropeptidases (DHPs) compared to that of imipenem or meropenem and were more stable to human DHP than imipenem (<10% hydrolysis compared to that for imipenem). THF carbapenems were stable to hydrolysis by all serine beta-lactamases tested. CL 191,121, a prototype THF carbapenem, was more stable to hydrolysis by carbapenem-hydrolyzing serine beta-lactamases such as IMI-1 and Sme-1 than imipenem, with a relative k(cat) value of <20% for imipenem. Similar to imipenem and meropenem, THF carbapenems were not stable to the metallo beta-lactamases CcrA and L1. However, CL 191,121 bound to all Staphylococcus aureus PBPs at concentrations that were less than or equal to the MICs. The THF carbapenems bound to PBPs from Escherichia coli and Pseudomonas aeruginosa, with the highest affinities being for PBPs 2 and 4, as noted with imipenem. The affinities for PBPs 1a and 1b in E. coli were reduced for the THF carbapenems compared to that for imipenem, even though the MICs of the THF carbapenems for E. coli strains were lower than those of imipenem. The penetrability of the THF carbapenems into Serratia marcescens S6, which produces the Sme-1 carbapenem-hydrolyzing beta-lactamase, was 2.4 to 7.8 times less than that of imipenem. Compounds CL 190,294 and CL 188,624 showed good penetrability, with permeability coefficient values comparable to those of the rapidly penetrating agents cephaloridine, imipenem, meropenem, and biapenem. Decreased penetration into wild-type P. aeruginosa was suggested by the high MICs of the THF carbapenems (MICs, 16 to 32 microg/ml), despite equivalent or better binding to P. aeruginosa PBPs than that of imipenem. However, the MICs of the THF carbapenems for wild-type P. aeruginosa compared to that for an OprD2 mutant generally varied no more than 2-fold, but those of imipenem and other carbapenems differed 16-fold. These data indicated that THF carbapenems do not appear to enter through protein OprD2. In conclusion, the THF carbapenems exhibited stability to hydrolysis by renal DHPs and serine beta-lactamases, exhibited strong binding to essential PBPs from E. coli and S. aureus, and penetrated gram-negative enteric bacteria at rates comparable to those for meropenem and biapenem.

Animals↗
PubMed1999

Optimizing culture of Chlamydia pneumoniae by using multiple centrifugations.

Three methods for the recovery of Chlamydia pneumoniae from spiked nasopharyngeal and blood specimens, including extended culture and additional centrifugations, were compared. Additional centrifugations and a 7-day culture time resulted in a 500- to 5, 000-fold increase in the number of detectable inclusion-forming units.

Cells, Cultured↗
PubMed1999

Technical solution for an interactive functional MR imaging examination: application to a physiologic interview and the study of cerebral physiology.

Studies with functional magnetic resonance (MR) imaging produce large unprocessed raw data sets in minutes. The analysis usually requires transferring of the data to an off-line workstation, and this process frequently occurs after the subject has left the MR unit. The authors describe a hardware configuration and processing software that captures whole-brain raw data files as they are being produced from the MR unit. It then performs the reconstruction, registration, and statistical analysis, and displays the results in seconds after completion of the MR image acquisition.

Brain↗
PubMed1999

Spatial analysis of the neuronal density of aminergic brainstem nuclei in primary neurodegenerative and vascular dementia: a comparative immunocytochemical and quantitative study using a graph method.

A graph method was employed to analyse spatial neuronal patterns of pontine nuclei with ascending aminergic projections to the forebrain (nucleus centralis superior (NCS), raphes dorsalis (NRD) and locus coeruleus (LC)), in Alzheimer disease (AD), Huntington disease (HD), and vascular (VD) as well as "mixed-type" (VA) dementia, compared with non-demented controls (CO) and a small sample of brains from schizophrenics ("dementia praecox" (DP)). The quantitative evaluations by the "minimal spanning tree (MST)" were complemented by rough neurofibrillary tangle (NFT) counts and by semiquantitative immunohistochemical assessment of amyloid deposition, neuritic plaque formation, and cellular gliosis. The AD cases showed a significant decline of neuronal density in all nuclei examined, as compared with controls and DP. Neuronal loss was not significant in VD, while the mixed cases with both vascular and Alzheimer-type pathology exhibited pronounced changes of neuronal density. Amyloid deposition occurred almost exclusively in AD and VA, as a rule, being of moderate degree, except for two presenile AD cases where it was marked. NFT were significantly increased in all nuclei in AD and in the VA cases, while they only occasionally appeared beyond age 55 in HD, DP and CO. The four HD cases showed in the NCS and NRD neuronal loss as severe as in AD. This neuronal loss implicates impairment of serotoninergic and noradrenergic neuromodulation as one basic mechanism promoting dementia in AD, VA and perhaps in HD.

Adult↗
PubMed1999

Comparative FISH-mapping of six expressed gene loci to river buffalo and sheep chromosomes.

Six expressed gene loci (NF1, CRYB1, CHRNB1, TP53, P4HB and GH1), recently assigned to cattle chromosome 19 by both radiation hybrid analysis and FISH-mapping, were comparatively FISH-mapped to river buffalo chromosome (BBU) 3p and sheep chromosome (OAR) 11, extending the physical map in these two important bovids. The six loci mapped to the same homoeologous chromosome bands of BBU 3p and OAR 11, and their gene order was centromere-NF1-CRYB1-CHNRB1-TP53-(GH1, P4HB).

Animals↗