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Biomedical subjects

H Wu

Publications and source records attributed to H Wu.

At least 649 records · Page 36Linked to original sources
PubMed1995

Comparison of effects of MPTCP and PTCP ceramics implanted for the treatment of bone defects in rabbits.

The magnetic porous tricalcium phosphate (MPTCP) and porous tricalcium phosphate (PTCP) ceramic cylinders were implanted into right and left bone defects of rabbits' radii in order to determine the utility of the MPTCP ceramics. Based on naked eye inspection, light and scanning electron microphotography, roentgenography, quantitative histological measurement of new bone formation and anti-break test for a period of 5 months. The results showed that the two kinds of ceramics were biocompatible with human tissue. MPTCP ceramics could induce more new bone formation than PTCP ceramics. Treatment of fractures with synthetic calcium phosphate ceramics and magnetic fields were discussed.

Animals↗
PubMed1995

[Arrhythmogenic right ventricular disease on a young peasant].

This article, together with literatures, discusses one case of arrhythmia right ventricular dysplasia (ARVD) we treated. This disease should be taken into account in some arrhythmias from right ventricle, especially refractory arrhythmias in youths. Some non-invasive techniques such as echocardiography, cardial single photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI) play more and more important role in the diagnosis of ARVD. These techniques can provide specific data for the early diagnosis.

Adult↗
PubMed1995

Cerebellar volume asymmetries are related to handedness: a quantitative MRI study.

Four cerebellar subregions were delineated (left, right; anterior, posterior), and their volumes measured on contiguous 3.1 mm coronal MR images in 15 dextral and 8 nondextral healthy control subjects. (1) Left and right cerebellar hemisphere volume asymmetries interacted with anterior-posterior level (anterior: right > left; posterior: left > right), following a pattern commonly found in the neocortex; (2) A significant handedness effect was found (P < or =0.01) on a composite index of cerebellar asymmetry, such that dextrals showed more asymmetry than nondextrals. These data suggest that the same pattern of asymmetries observed at the neocortical level is also present in the metencephalon. These asymmetries, possibly resulting from multiple developmental growth gradients acting on the metencephalon early in gestation, are associated with handedness differences in adulthood.

Adult↗
PubMed1995

Triterpenoid saponins from Clematis chinensis.

From the roots of Clematis chinensis, two new triterpenoid saponins, named clematichinenoside A and B, were isolated and their structures were elucidated as 3-O-beta-D-ribopyranosyl-(1-3)-alpha-L-rhamnopyranosyl-(1-2)-alpha -L- arabinopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester and 3-O-beta-D-glucopyranosyl-(1-4)-beta-D-ribopyranosyl-(1-3)-alpha-L - rhamnopyranosyl-(1-2)-alpha-L-arabinopyranosyl hederagenin 28-O-alpha-L-rhamnopyranosyl-(1-4)-beta-D-glucopyranosyl-(1-6)- beta-D-glucopyranosyl ester, respectively. In addition oleanolic acid, hederagenin and seven known saponins were obtained.

Carbohydrate Conformation↗
PubMed1995

Medicagenic acid saponins from Aster batangensis.

Two new medicagenic acid saponins, named asterbatanoside J and K, were isolated from the roots of Aster batangensis. On the basis of chemical and spectral studies especially 2D NMR including COSY, HETCOR, HMQC, HOHAHA, TOCSY, ROESY and HMBC techniques, their structures were established as 3-O-beta-D-glucopyranosyl-(1--> 6)-beta-D-glucopyranosyl-2 beta, 3 beta-dihydroxy-olean-12-en-23 alpha, 28-dioic acid- 28-O-alpha-L-arabinopyranosyl-(1-->3)-alpha-L- rhamnopyranosyl-(1-->2)-beta-D-fucopyranoside and 3-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl- medicagenic acid-28-O-beta-D-xylopyranosyl-(-->4)-[alpha-L- arabinopyranosyl-(1 -->3)-alpha-L-rhamnopyranosyl-(1-->2) -beta-D-fucopyranside, respectively.

Carbohydrate Conformation↗
PubMed1995

PCR amplification and DNA sequencing of SRV-2 from archived tumor tissues.

Fibroproliferative tumors, known as retroperitoneal fibromatosis (RF) are predominantly associated with type D simian retrovirus serotype 2 (SRV-2) infections in pigtailed macaques (Macaca nemestrina) at the University of Washington Regional Primate Research Center (UWRPRC). In this report we examined genetic changes that occurred in SRV-2/Washington (SRV-2/WA) from archived RF tissues and from fresh tissue and lymphocytes. DNA was extracted from paraffin-embedded RF tumor tissues and was used to amplify a portion of the SRV-2/WA genome encoding an open reading frame, 3'orf. Since 3'orf is encoded in an alternate reading frame within the outer membrane glycoprotein (gp70) env gene, sequences of 3'orf also provide information on a portion of env gp70. To define the changes that have occurred in this portion of the viral genome, we compared the nucleotide and deduced amino acid sequences amplified from the various tumor tissues. The paraffin section PCR revealed that all samples containing amplifiable DNA harbored SRV-2/WA genomes. DNA sequence analysis showed that the 3'orf/gp70 portion of the SRV-2/WA genome was nearly identical in all tissues but was distinguishable from the prototype SRV-2/OR isolate from Celebes black macaques (M. nigra). A T-cell activating domain (Env residues 233-249) was 100% conserved in the SRV-2/WA isolates.

Amino Acid Sequence↗
PubMed1995

Anterior hippocampal volume reductions predict frontal lobe dysfunction in first episode schizophrenia.

This study examined relations of mesiotemporal lobe tissue volumes with neuropsychological (NP) functions in a sample of patients with first episode schizophrenia. Three contiguous compartments of the mesiotemporal lobe were measured on magnetic resonance images, comprising primarily amygdaloid, anterior hippocampal, and posterior hippocampal tissue volumes. NP measures were derived from a comprehensive battery. Decreased volume selectively in the anterior hippocampal formation was associated with lower scores on measures of executive and motor functions usually considered sensitive to the integrity of frontal lobe systems. Measures of other NP functions, and global intellectual ability, were not related to mesiotemporal volumes. The findings that morphologic abnormalities in the mesiotemporal lobe are associated with impairment of frontal lobe functions point to a defect in an integrated functional system that includes both frontal and mesiotemporal components. The findings are consistent with the hypothesis that neurodevelopmental defects affecting the morphology of the anterior hippocampal formation may be manifest later in life as impairments in fronto-limbic control. .

Acute Disease↗
PubMed1995

A PCR-derived, non-isotopic labeled prolactin cRNA probe suitable for in situ hybridization.

We have developed a novel vector-free method for the synthesis of nonisotopic (digoxigenin) labeled prolactin (PRL)-gene specific cRNA probe based on the direct in vitro transcription of DNA template amplified by polymerase chain reaction (PCR). The T7 and T3 RNA polymerase promoters were incorporated into the amplified DNA by including the promoter sequences in the '5 end of the oligonucleotides used to prime the PCR. These promoters allowed the subsequent transcription of digoxigenin labeled antisense and sense cRNA probes from the amplified DNA. We successfully utilized these probes to detect specific PRL mRNA in human pituitary and decidua tissues by in situ hybridization (ISH) which can provide identification and localization of PRL-gene expression at a single cell level. This approach avoided time consuming steps which required subcloning of target DNA into the vectors that contains bacteriophage RNA polymerase promoter as well as the need for radioactive materials. This non-isotopic ISH procedure takes less than 72 h from specimen preparation to microscopic analysis and should prove to be useful for molecular biological studies of hormones and clinical diagnosis.

Base Sequence↗
PubMed1995

A targeted mutation at the known collagenase cleavage site in mouse type I collagen impairs tissue remodeling.

Degradation of type I collagen, the most abundant collagen, is initiated by collagenase cleavage at a highly conserved site between Gly775 and Ile776 of the alpha 1 (I) chain. Mutations at or around this site render type I collagen resistant to collagenase digestion in vitro. We show here that mice carrying a collagenase-resistant mutant Col1a-1 transgene die late in embryo-genesis, ascribable to overexpression of the transgene, since the same mutation introduced into the endogenous Col1a-1 gene by gene targeting permitted normal development of mutant mice to young adulthood. With increasing age, animals carrying the targeted mutation developed marked fibrosis of the dermis similar to that in human scleroderma. Postpartum involution of the uterus in the mutant mice was also impaired, with persistence of collagenous nodules in the uterine wall. Although type I collagen from the homozygous mutant mice was resistant to cleavage by human or rat fibroblast collagenases at the helical site, only the rat collagenase cleaved collagen trimers at an additional, novel site in the nonhelical N-telopeptide domain. Our results suggest that cleavage by murine collagenase at the N-telopeptide site could account for resorption of type I collagen during embryonic and early adult life. During intense collagen resorption, however, such as in the immediate postpartum uterus and in the dermis later in life, cleavage at the helical site is essential for normal collagen turnover. Thus, type I collagen is degraded by at least two differentially controlled mechanisms involving collagenases with distinct, but overlapping, substrate specificities.

Amino Acid Sequence↗
PubMed1995

Interferon regulatory factor element and interferon regulatory factor 1 in the induction of major histocompatibility complex class I genes in neural cells.

The role of the MHC-IRF-E and interferon regulatory factor 1 (IRF-1) in the regulation of MHC class I genes in astrocytes was analyzed. Transcriptional activation of MHC class I genes after treatment of astrocytes with various inducers occurred over a period of hours and correlated with cell surface expression. Functional analysis of the MHC class I gene promoter region confirmed that induction was controlled by a restricted region of 88 base pairs containing two well-defined inducible enhancers, the MHC-CRE and the MHC-IRF-E. Further analysis showed that potential MHC-CRE enhancer activity was silent. Therefore, the MHC-IRF-E, rather than the MHC-CRE, appeared responsible for enhancement of the MHC class I gene and was supported by three findings: (1) site-directed mutation of the MHC-IRF-E-abrogated induction, (2) promoter constructs containing IRF-Es as the sole enhancers were highly inducible in astrocytes, and (3) the expression of transcription factor IRF-1, which acts through the MHC-IRF-E to induce MHC class I genes, was induced to high levels in parallel with that of MHC class I induction. The induction of the IRF-1 gene correlated with the prior induction of the gamma-activated factor (GAF) or NF-kappa B, depending on the inducer, indicating that both gamma activation sites (GAS) and kappa B sites in the IRF-1 promoter are important.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Immunocytochemistry of Kaposi's sarcoma-like tumor cells from pigtailed macaques with simian AIDS.

Some macaques infected with SRV-2 developed SAIDS and RF, a Kaposi's sarcoma (KS)-like tumor. We investigated the immunophenotypic markers of this SAIDS-associated retroperitoneal fibromatosis (RF). RF tumor is characterized by proliferation of spindle cells accompanying inflammatory cell infiltrates, fibroblasts, and endothelial cells. RF spindle cells in tumor tissues revealed several immunobiologic characteristics similar to vascular smooth-muscle cells or myofibroblasts based on positive immunoreactivity of smooth-muscle alpha-actin and desmin. The majority of cultured RF spindle cells also expressed specific markers for vascular smooth muscle. These results suggest that the RF spindle cells are derived from vascular smooth-muscle cells. Furthermore, RF tissues and cells were persistently infected with SRV-2, which may play an important role in viral etiology of AIDS-associated neoplasm in this macaque model.

Animals↗
PubMed1995

Identification of two pigments and a hydroxystilbene antibiotic from Photorhabdus luminescens.

Two yellow pigments were isolated for the first time from the entomopathogenic bacterium Photorhabdus luminescens in liquid culture and were identified as the anthraquinone derivatives 3,8-dimethoxy-1-hydroxy-9,10-anthraquinone (minor) and 1,3-dimethoxy-8-hydroxy-9,10-anthraquinone (major). A known antibiotic, 3,5-dihydroxy-4-isopropylstilbene, was also detected and for the first time showed strong fungicidal activity against several fungi of medical and agricultural importance.

Anthraquinones↗
PubMed1995

A functional cyclic AMP response element plays a crucial role in neuroendocrine cell type-specific expression of the secretory granule protein chromogranin A.

Chromogranin A, a soluble acidic protein, is a ubiquitous component of secretory vesicles throughout the neuroendocrine system. We reported previously the cloning and initial characterization of the mouse chromogranin A gene promoter, which showed that the promoter contains both positive and negative domains and that a proximal promoter spanning nucleotides -147 to +42 bp relative to the transcriptional start site is sufficient for neuroendocrine cell type-specific expression. The current study was undertaken to identify the particular elements within this proximal promoter that control tissue-specific expression. We found that deletion or point mutations in the potential cAMP response element (CRE) site at -68 bp virtually abolished promoter activity specifically in neuroendocrine (PC12 chromaffin or AtT20 corticotrope) cells, with little effect on activity in control (NIH3T3 fibroblast) cells; thus, the CRE box is necessary for neuroendocrine cell type-specific activity of the chromogranin A promoter. Furthermore, the effect of the CRE site is enhanced in the context of intact (wild-type) promoter sequences between -147 and -100 bp. DNase I footprint analysis showed that these regions (including the CRE box) bind nuclear proteins present in both neuroendocrine (AtT20) and control (NIH3T3) cells. In AtT20 cells, electrophoretic mobility shift assays and factor-specific antibody supershifts showed that an oligonucleotide containing the chromogranin A CRE site formed a single, homogeneous protein-DNA complex containing the CRE-binding protein CREB. However, in control NIH3T3 cells we found evidence for an additional immunologically unrelated protein in this complex. A single copy of this oligonucleotide was able to confer neuroendocrine-specific expression to a heterologous (thymidine kinase) promoter, albeit with less fold selectivity than the full proximal chromogranin A promoter. Hence, the CRE site was partially sufficient to explain the neuroendocrine cell type specificity of the promoter. The functional activity of the CRE site was confirmed through studies of the endogenous chromogranin A gene. Northern mRNA analysis showed that expression of the endogenous chromogranin A gene was stimulated seven- to eightfold by cAMP in PC12 cells, whereas no induction occurred in the NIH3T3 cells. Similar cAMP induction was obtained with the transfected chromogranin A promoter in PC12 cells, and abolition of the CRE site (by deletion or point mutation) eliminated the induction. Thus, the CRE site in the chromogranin A proximal promoter is functional and plays a crucial, indeed indispensable, role in neuroendocrine-specific expression of the gene. These results also provide insight into transcriptional mechanisms governing acquisition of the neuroendocrine secretory phenotype.

3T3 Cells↗
PubMed1995

The expression, characterization, and crystallization of wild-type and selenomethionyl human chorionic gonadotropin.

Although the glycoprotein hormone hCG was crystallized over 4 yr ago, it is only now that three-dimensional structural information is available. This manuscript reports the method for successful production of modified expressed hormone, the characteristics of the crystallized protein, and unexpected observations during the crystallization process. Two different routes of solution to the structure of hCG were followed. The first was based on the traditional method of heavy atom isomorphous replacement, and the second was the more novel method of expressing the protein with selenomethionine substituting for methionine and applying multiwavelength anomalous diffraction analysis. Selenomethionyl hCG was employed to successfully grow the crystals used for the solution of the structure of hCG after partial deglycosylation by hydrogen fluoride (HF) treatment. The selenomethionyl hCG proved to be more hydrophobic than the expressed form of native hCG. Furthermore, expressed forms of hCG that were deglycosylated by HF proved to be more intact and less susceptible to peptide bond cleavages during the crystallization process than the urinary form of HF-treated hCG studied previously. It was found that addition of reducing agent during the crystallization period was necessary for the growth of crystals of HF-treated selenomethionyl hCG suitable for diffraction studies. Growth of crystals of HF-treated expressed hCG were accelerated by the addition of dithiothreitol, but would successfully grow without reductant. HPLC analysis of the HF-treated hormones before and during the crystallization process was used to identify alterations in the molecules, including oxidation and aggregation, both of which may affect the growth of crystals.

Animals↗
PubMed1995

[The effective time of HX solution for rat liver preservation].

The effects of HX solution and UW solution for rat liver preservation were studied with non-circulated isolated perfused rat liver model. Sixty-six inbred Wistar rat livers were randomly preserved for 12, 18, 24, and 30h with HX solution or UW solution. The effects were assessed by measuring hepatic tissue water content, sinusoidal lining cell mortality, Krebs-Henseleit's perfusate aspartate aminotransferase, the number of livers secreting bile during isolated perfusion, and by observing the morphological changes in liver. The experimental results suggest that the effects of HX solution for rat liver preservation be similar to those of UW solution within 24h storage.

Adenosine↗