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Biomedical subjects

H Zhou

Publications and source records attributed to H Zhou.

At least 523 records · Page 29Linked to original sources
PubMed1997

[Immunohistochemical study on the decidua vessels in recurrent spontaneous abortion].

OBJECTIVE: To investigate the effects of uterine local immunological factors in recurrent spontaneous abortion (RSA). METHODS: The decidua vessels were studied by immunohistochemical ABC method in 26 cases of RSA and 10 cases of normal pregnant women (control group). Meanwhile, serum IgG, IgM, IgA, C3 and CH50 were determined in RSA group and in control group. RESULTS: In RSA cases, the depositions of IgM (17 cases, 80.8%) were significantly increased (P < 0.001, respectively) as compared with the control group, the depositions of IgG (2 cases, 7.8%) were significantly decreased (P < 0.001); the levels of serum C3, CH50 were significantly decreased (P < 0.01 respectively), but the level of serum IgA was increased significantly (P < 0.05) as compared with the control group. The depositions of C3 were significantly increased in RSA who had autoantibodies (P < 0.01), as compared with those without autoantibodies. In addition, the positive stain of IGM and C3 in the cytoplasm and nuclei of decidua cells and in the cytoplasm of gland cells of some RSA patients were also observed. CONCLUSION: The results suggest that the immunological damage of decidua vessels is a very important factor in immunopathogenesis for RSA. Decidua cells and gland cells may have potential immunological function.

Abortion, Habitual↗
PubMed1997

[The design of an OEM module-based hand-hold pulse oximeter].

This paper describes the software and hardware design of an OEM module-based hand-hold pulse oximeter. The instrument has the features of compact structure, reliable performance, having all the necessary functions, providing measurements on any patients and low power consumption. It is possible to make this instrument as a commercial product in shorter period.

Equipment Design↗
PubMed1997

[Effects of smoking on oxygen free radicals and fibrinolytic system].

UNLABELLED: The effects of smoking on SOD, MDA, t-PA, PAI-1 were studied in 20 healthy men (10 smokers and 10 nonsmokers). RESULTS: SOD decreased and MDA increased significantly in smokers. After acute smoking, SOD decreased and MDA increased significantly in all the subjects, t-PA and PAI-1 activities were increased immediately after acute smoking. There was a significant positive relationship between increased t-PA and SOD, whereas a significant negative relationship exists between increased t-PA and MDA. CONCLUSION: Smoking increases oxygen free radicals. The release of t-PA is decreased in smokers, that might be resulted from the increases of oxygen free radicals.

Adult↗
PubMed1997

[Effects of inhalated isosorbide dinitrate on endothelin and nitric oxide and its therapeutic efficacy for experimental guinea-pigs with asthma].

To probe into the correlation between the changes of endothelin and nitric oxide in bronchial alveolar lavage fluid (BALF) and the treatment of inhaling isosorbide dinitrate on experimental guinea pigs with asthma, we divided 25 guinea pigs randomly into three groups (Control group, Asthma group, Isosorbide dinitrate group), and induced some subjects by inhalation of aerosolized ovalbumin as the model of asthma to investigate the endothelin (ET) and nitric oxide (NO) level in BALF as well as the pathological change of the respiratory tract. We found that the level of endothelin and nitric oxide in BALF were all elevated in experimental guinea pigs with asthma, but the degree of increase of NO in BALF was lower than that of ET. The NO and the ET levels in BALF were negative correlation (r = -0.8050, P < 0.01). After having been treated with aerosolized isosorbide dinitrate, the NO level in BALF was significantly elevated and the ET level in BALF was decreased in comparison with the asthma group (P < 0.001, respectively). Moreover, the eosinophile infiltration, exoserosis, and epithalaxia of the respiratory tract of the guinea-pigs were all lightened. The results suggest that inhaled isosoratory dinitrate could be used for treating asthma, and its mechanism may be elevation of NO level and decrease of ET level in BALF.

Administration, Inhalation↗
PubMed1996

Characterization of ADP-ribosylation sites on desmin and restoration of desmin intermediate filament assembly by de-ADP-ribosylation .

Desmin is an intermediate filament protein that can be ADP-ribosylated by arginine-specific mono(ADP-ribosyl) transferase. Stoichiometric modification of desmin by the transferase causes inhibition of assembly of desmin into 10-nm intermediate filaments (Huang et al., 1993, Biochem. Biophys. Res. Commun. 197, 570-577). In this work, the sites of modification that can affect disassembly have been identified. ADP-ribosylated desmin (1.2 mol ADP-ribose/mol desmin) was digested with lysyl endopeptidase followed by trypsin. Two ADP-ribosylated peptides were obtained, sequenced by Edman degradation, and analyzed by the use of matrix-assisted laser desorption/ionization mass spectrometry. Arginines 48 and 68 of desmin's head domain were shown to be sites of modification, with arginine 48 the major ADP-ribosylation site. ADP-ribosylated desmin (4 mol ADP-ribose/mol desmin) was treated with ADP-ribosylarginine hydrolase. Removal of more than three ADP-ribose groups results in partial restoration of desmin's ability to form intermediate filaments. It is necessary to remove all ADP-ribose groups from desmin to restore its complete ability to form intermediate filaments. The fact that the effect of ADP-ribosylation on the filament-forming properties of desmin is fully reversible suggests that ADP-ribosylation alone is responsible for the changes noted in desmin.

ADP Ribose Transferases↗
PubMed1996

Lithologic Control of the Depth of Earthquakes in Southern California

The depth distribution of southern California earthquakes indicates that areas underlain by schist basement rocks have a shallower (4 to 10 kilometers) maximum depth of earthquakes than do areas with other types of basement rocks. The predominant minerals in the schists become plastic at lower temperatures, and thus at shallower depths, than the minerals in the other basement rocks. The lateral variations in lithology will control the depth extent (and thus the magnitudes) of potential future earthquakes; these depths can be determined from the depth of the current background seismicity.

Journal Article↗
PubMed1996

Target proteins for arginine-specific mono(ADP-ribosyl) transferase in membrane fractions from chick skeletal muscle cells.

In a previous study, we found that a specific inhibitor of cellular arginine-specific mono(ADP-ribosyl) transferase, meta-iodobenzylguanidine (MIBG), reversibly inhibited both proliferation and differentiation of cultured embryonic chick primary muscle myoblasts. In addition, we observed that arginine-specific ADP-ribosyltransferase activity increased with muscle-cell differentiation in cultures. Therefore, muscle-cell cultures, especially the 96-h myotube cultures that contain the highest levels of ADP-ribosyltransferase, were used as a working system to determine the cellular protein substrates for arginine-specific ADP-ribosyltransferase. When membrane fractions extracted from 96-h chick myotubes were incubated with [32P]NAD at 30 degrees C for 30 min, only a few proteins were labeled. The labeling of two proteins of 36 and 56 kDa was inhibited by the presence of an arginine-specific mono(ADP-ribosyl) transferase inhibitor, MIBG, and by novobiocin. To prove that these proteins are indeed the targets for arginine-specific mono(ADP-ribosyl)ation, active recombinant muscle ADP-ribosyltransferase was incubated with membrane proteins under the same conditions. ADP-ribosylation of these two membrane proteins, as seen in the endogenous reactions, was also catalyzed by the added muscle transferase and was also inhibited by MIBG and novobiocin. By using antibody specific for desmin for immunoprecipitation and immunoblot analysis, we found that a 56-kDa protein associated with the membrane of myotubes is desmin. Our results showed that incorporation of isotope into this protein band from [32P]NAD is due to ADP-ribosylation of desmin.

3-Iodobenzylguanidine↗
PubMed1996

The role of gp130-mediated signals in osteoclast development: regulation of interleukin 11 production by osteoblasts and distribution of its receptor in bone marrow cultures.

Interleukin (IL)-11 is a multifunctional cytokine whose role in osteoclast development has not been fully elucidated. We examined IL-11 production by primary osteoblasts and the effects of rat monoclonal anti-mouse glycoprotein 130 (gp130) antibody on osteoclast formation, using a coculture of mouse osteoblasts and bone marrow cells. IL-1, TNF alpha, PGE2, parathyroid hormone (PTH) and 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3) similarly induced production of IL-11 by osteoblasts, but IL-6, IL-4, and TGF beta did not. Primary osteoblasts constitutively expressed mRNAs for both IL-11 receptor (IL-11R alpha) and gp130. Osteotropic factors did not modulate IL-11R alpha mRNA at 24 h, but steady-state gp130 mRNA expression in osteoblasts was upregulated by 1 alpha,25(OH)2D3, PTH, or IL-1. In cocultures, the formation of multinucleated osteoclast-like cells (OCLs) in response to IL-11, or IL-6 together with its soluble IL-6 receptor was dose-dependently inhibited by rat monoclonal anti-mouse gp130 antibody. Furthermore, adding anti-gp130 antibody abolished OCL formation induced by IL-1, and partially inhibited OCL formation induced by PGE2, PTH, or 1 alpha,25(OH)2D3. During osteoclast formation in marrow cultures, a sequential relationship existed between the expression of calcitonin receptor mRNA and IL-11R alpha mRNA. Osteoblasts as well as OCLs expressed transcripts for IL-11R alpha, as indicated by RT-PCR analysis and in situ hybridization. These results suggest a central role of gp130-coupled cytokines, especially IL-11, in osteoclast development. Since osteoblasts and mature osteoclasts expressed IL-11R alpha mRNA, both bone-forming and bone-resorbing cells are potential targets of IL-11.

Animals↗
PubMed1996

Analysis of cis-acting elements required for replication of barley stripe mosaic virus RNAs.

The replicative abilities of mutant RNA transcripts derived from barley stripe mosaic virus cDNA clones were investigated in barley protoplasts that had been coinoculated with wild-type RNA alpha and -gamma transcripts. The 5' and 3' noncoding regions were required for replication, and lack of a 5' cap structure (GpppG) reduced the replicative ability substantially. All internal deletions within RNA alpha abrogated replication in trans. A 2-base change that produced a truncated alpha a protein lacking the first 16 amino acids also compromised the ability of RNA alpha to be replicated. In contrast, RNA beta transcripts containing deletions involving each ORF and the downstream poly(A) tract were effectively amplified by RNAs alpha and gamma, but collective deletion of all four ORFs drastically reduced accumulation. The intergenic region between beta a and beta b was not absolutely required for replication, but small deletions within this region reduced the abundance of RNA beta by at least 10-fold. Deletions within the first 507 nt of the gamma a ORF abrogated replication. However, transcripts containing deletions within the central and 3' regions of the gamma a ORF, the gamma a--gamma b intergenic region, and the gamma b ORF could be amplified in trans. Two mutants containing extensive deletions encompassing the central region of the gamma a ORF and most of gamma b behaved like defective interfering RNAs because they multiplied to high levels in trans and caused a pronounced reduction in accumulation of the coinoculated wild-type RNAs alpha and gamma.

Base Sequence↗
PubMed1996

Tyrosine kinase inhibitors. 10. Isomeric 4-[(3-bromophenyl)amino]pyrido[d]-pyrimidines are potent ATP binding site inhibitors of the tyrosine kinase function of the epidermal growth factor receptor.

Following the discovery of the very high inhibitory ability of the 4-[(3-bromophenyl)amino]-quinazolines against the tyrosine kinase activity of the epidermal growth factor receptor (EGFR) (e.g., 3, IC50 0.029 nM), four series of related pyrido[d]pyrimidines bearing electron-donating groups at the 6- or 7-positions have been synthesized and evaluated. The compounds were prepared by nucleophilic substitution of the corresponding 6- and 7-fluoro analogues. While members of all series showed potent inhibitory activity against isolated EGFR, there were important differences between the different isomeric pyrido[d]pyrimidines and the parent quinazolines. Overall, the [3,4-d] and [4,3-d] series were the most potent, followed by the [3,2-d] compounds, with the [2,3-d] analogues being least active. Whereas in the parent quinazoline series the addition of steric bulk to a 6- or 7-NH2 substituent (i.e., NHMe and NMe2 groups) dramatically decreased potency, no such trend was discernable in the [3,2-d] series. Furthermore, in the 7-substituted pyrido[4,3-d]- and 6-substituted pyrido[3,4-d]pyrimidine series, and to a limited extent in the 7-substituted pyrido[2,3-d] series, such substitution increased potency dramatically, to the extent that the 7-(methylamino)pyrido[4,3-d]pyrimidine (5f) (IC50 0.13 nM) and 6-(methylamino)pyrido[3,4-d]pyrimidine (7f) (IC50 0.008 nM) constitute important new leads. Selected compounds were evaluated for their ability to inhibit EGFR autophosphorylation in A431 cells, and a positive quantitative correlation was found between this activity and inhibitory activity against the isolated enzyme.

ErbB Receptors↗
PubMed1996

Retina-derived POU-domain factor-1: a complex POU-domain gene implicated in the development of retinal ganglion and amacrine cells.

A novel POU-domain protein, retina-derived POU-domain factor-1 (RPF-1), has been identified through the isolation of cDNA and genomic DNA clones. In the adult, RPF-1 is expressed only within the CNS, where its expression is restricted to the medical habenulla, to a dispersed population of neurons in the dorsal hypothalamus, and to subsets of ganglion and amacrine cells in the retina. The human RPF-1 gene spans > 125 kb and gives rise to multiple differentially spliced transcripts. In the human retina, the most abundant mRNA isoforms are derived from an alternate splicing event that inserts an evolutionarily conserved peptide of 36 amino acids into the DNA recognition helix of the POU-specific domain. In vitro, the RPF-1 POU domain lacking the insert binds to a consensus Oct-1 binding site, whereas the alternately spliced POU domain does not. RPF-1 protein first appears in the developing mouse retina at e11, where it localizes to neuroblasts that have recently migrated from the mitotic zone to the future ganglion cell layer. These data suggest that RPF-1 is likely to be involved in early steps in the differentiation of amacrine and ganglion cells.

Age Factors↗
PubMed1996

Oxygen and one reducing equivalent are both required for the conversion of alpha-hydroxyhemin to verdoheme in heme oxygenase.

Heme oxygenase is a central enzyme of heme degradation and associated carbon monoxide biosynthesis. We have prepared the alpha-hydroxyheme-heme oxygenase complex, which is the first intermediate in the catalytic reaction. The active site structure of the complex was examined by optical absorption, EPR, and resonance Raman spectroscopies. In the ferric form of the enzyme complex, the heme iron is five coordinate high spin and the alpha-hydroxyheme group in the complex assumes a structure of an oxophlorin where the alpha-meso hydroxy group is deprotonated. In the ferrous form, the alpha-hydroxy group is protonated and consequently the prosthetic group assumes a porphyrin structure. The alpha-hydroxyheme group undergoes a redox-linked conversion between a keto and an enol form. The ferric alpha-hydroxyheme reacts with molecular oxygen to form a radical species. Reaction of the radical species with a reducing equivalent yields the verdoheme-heme oxygenase complex. Reaction of the ferrous alpha-hydroxyheme-heme oxygenase complex with oxygen also yields the verdoheme-enzyme complex. We conclude that the catalytic conversion of ferric alpha-hydroxyheme to verdoheme by heme oxygenase requires molecular oxygen and one reducing equivalent.

Animals↗
PubMed1996

Selection of trypsin inhibitors in phage peptide library.

The newly developed techniques of peptide libraries have become a conventional and efficient method in screening ligands of proteins of interest. We present here the successful results of selection of trypsin inhibitors in a phage hexapeptide library. After affinity selection and activity assay, peptide sequences, deduced from DNA sequencing of the phage peptides with the most striking trypsin activity, share some common features with trypsin inhibitors reported. All of the phage peptides selected out and those native and synthetic trypsin inhibitors reported are composed of three parts: (a) positively charged part (Arg, Lys or their analogs); (b) polar part that may form hydrogen bonds with Ser in the active site of trypsin; (c) hydrophobic part that interacts with the nonpolar region of trypsin active site.

Amino Acid Sequence↗
PubMed1996

Expression of the barley stripe mosaic virus RNA beta "triple gene block".

Genomic RNA beta of barley strip mosaic virus (BSMV) contains four defined open reading frames (ORFs). These include the coat protein (beta a) and a "triple gene block" consisting of the beta b, beta c, and beta d ORFs that overlap one another. Two subgenomic beta RNAs (sgRNA beta 1 and sgRNA beta 2) with sizes of 2.5 and 0.96 kb were identified in BSMV-infected protoplasts, and their transcription initiation sites were mapped to nucleotides 789 and 2327, respectively, of RNA beta by primer extension experiments. In a cell-free wheat germ translation system, genomic RNA beta served as a mRNA only for the 22-kDa coat protein, and sgRNA beta 1 directed synthesis of only the 58-kDA beta b protein. However, with sgRNA beta 2, three proteins with sizes of 14, 17, and 23 kDa were synthesized. Both the 14- and the 23-kDa proteins were recognized by the beta d antibodies in vitro and in vivo. These results demonstrated that the 14-kDa protein was encoded by the beta d ORF and suggested that the 23-kDa protein, designated beta d', is a readthrough product of the amber stop codon of the beta d ORF. Mutagenesis of sgRNA beta 2 revealed that the 17-kDa protein was a product of the beta c ORF. Expression of sgRNA beta 1 and sgRNA beta 2 was also investigated with the chloramphenicol acetyl transferase (CAT) reporter gene in protoplasts coinfected with RNAs alpha and gamma plus chimeric RNA beta derivatives containing the CAT gene in-frame with the beta b, beta c, beta d, or beta d' ORFs. Elimination of the sgRNA beta 1 promoter abolished CAT expression from the beta b-CAT chimeric RNA, and removal of the sgRNA beta 2 promoter prevented CAT expression from the beta c-CAT, beta d-CAT, and beta d'-CAT chimeric RNAs. Taken together, these results demonstrate that the BSMV coat protein is the sole translation product of the genomic RNA beta, whereas sgRNA beta 1 serves as a messenger for translation of the beta b protein, and sgRNA beta 2 functions as a messenger for translation of beta c and beta d and the newly discovered beta d' protein. Additional mutagenesis experiments indicate that beta c is translated by a leaky scanning mechanism.

Base Sequence↗
PubMed1996

Modulation of the rat alveolar macrophage respiratory burst by hydroperoxides is calcium dependent.

Sublethal concentrations of hydroperoxides (H2O2 or tert-butylhydroperoxide) produce a dual effect upon the respiratory burst of rat alveolar macrophages in which low concentrations (< 50 microM) enhance and higher concentrations (> 50 microM) produce inhibition (J. K. Murphy, et al., Free Radical. Biol. Med. 18, 37-45, 1995). These effects correlate with transient versus sustained elevation of [Ca2+]i caused by exposure to hydroperoxides prior to stimulation of the respiratory burst. In the present study changes in [Ca2+]i caused by exposure to sublethal levels of hydroperoxide were buffered by incubating macrophages with the acetoxy-methyl ester of BAPTA, an intracellular Ca2+ chelator. The enhancement of the phorbol ester-stimulated respiratory burst by tBOOH was abolished by BAPTA, while the inhibition was attenuated. Thus, the modulation by tBOOH appears to be largely dependent upon the changes in [Ca2+]i. Receptor mediated stimulation of the respiratory burst (ADP stimulation) involves release of Ca2+ from the inositol-1,4,5-triphosphate (IP3)-sensitive pool in the endoplasmic reticulum. Comparisons were made of the effects of thapsigargin (TG), an endoplasmic reticulum Ca-ATPase inhibitor, with tBOOH on release of intracellular Ca2+ and the respiratory burst. Treatment with TG did not affect changes in [Ca2+]i caused by tBOOH or vice versa. Although TG decreased the ADP-stimulated respiratory burst, it had no effect upon tBOOH modulation. Thus, the effect of tBOOH upon the respiratory burst is dependent upon the release of Ca2+ and the release of Ca2+ occurs from a non-IP3-dependent pool. This aberrant mimicry of normal signal transduction underlies oxidative modulation of the respiratory burst.

Animals↗