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L Y Chang

Publications and source records attributed to L Y Chang.

At least 127 records · Page 7Linked to original sources
PubMed1985

[A monoclonal antibody against ragweed pollen cross-reacting with yellow dock pollen].

Using monoclonal antibodies with different specificity against the major allergenic components of ragweed pollen, we analyzed their cross-reactivity with two tree pollens, two grass pollens and five other weed pollens which are common in Taiwan by the immunoblot method. It was found that besides reacting with AgE and AgK of the ragweed pollen, the monoclonal antibody 48-5 also reacted with antigens of yellow dock pollen with molecular weights of 40K, 38K, 24K, and 21K. In a preliminary study, sera of two patients containing IgE antibodies to ragweed pollen antigens also reacted to the 40K component of the yellow dock pollen. Furthermore, from the results of allergenic skin testings on 109 patients with bronchial asthma, we found that of 22 patients who had a positive reaction to a crude extract of ragweed pollen, 18(81.8%) also reacted to the crude extract of yellow dock pollen. In conclusion, our results suggest that there exists a common allergenic determinant between pollens of ragweed and yellow dock. It may play an important role in the expression of the sensitivity of patients to these two kinds of pollens.

Allergens↗
PubMed1984

Isolation and nucleotide sequence analysis of the beta-type globin pseudogene from human, gorilla and chimpanzee.

The beta-globin gene cluster of human, gorilla and chimpanzee contain the same number and organization of beta-type globin genes: 5'-epsilon (embryonic)-G gamma and A gamma (fetal)-psi beta (inactive)-delta and beta (adult)-3'. We have isolated the psi beta-globin gene regions from the three species and determined their nucleotide sequences. These three pseudogenes each share the same substitutions in the initiator codon (ATG----GTA), a substitution in codon 15 which generates a termination signal TGG----TGA, nucleotide deletion in codon 20 and the resulting frame shift which yields many termination signals in exons 2 and 3. The basic structure of these psi beta-globin genes, however, remains consistent with that found for functional beta-globin genes: their coding regions are split by two introns, IVS 1 (which splits codon 30, 121 base-pairs in length) and IVS 2 (which splits codon 104, 840 to 844 base-pairs in length). These introns retain the normal splice junctions found in other eukaryotic split genes. The three hominoid psi beta-globin genes show a high degree of sequence correspondence, with the number of differences found among them being only about one-third of that predicted for DNA sites evolving at the neutral rate (i.e. for sites evolving in the absence of purifying selection). Thus, there appears to be a deceleration in the rate of evolution of the psi beta-globin locus in higher primates.

Animals↗
PubMed1984

Selective activation of particulate guanylate cyclase by a specific class of porphyrins.

Guanylate cyclase was activated 3- to 10-fold by hemin in a dose-dependent manner in membranes prepared from homogenates of rat lung, C6 rat glioma cells, or B103 rat neuroblastoma cells. Maximum activation was observed with 50 to 100 microM hemin with higher concentrations being inhibitory. Activation was observed when Mg2+-GTP but not when Mn2+-GTP was used as the substrate. Increased enzyme activity reflected selective activation of the particulate form of guanylate cyclase; hemin inhibited the soluble form of guanylate cyclase 70 to 90% over a wide range of concentrations. Activation was not secondary to proteolysis since a variety of protease inhibitors failed to alter stimulation by hemin. Protophorphyrin IX had little effect on particulate guanylate cyclase activity and sodium borohydride almost completely abolished hemin-dependent activation. These data suggest a requirement for the ferric form of the porphyrin-metal chelate for activation. However, agents which interact with the iron nucleus of porphyrins, such as cyanide, had little effect on the ability of hemin to activate guanylate cyclase. The stimulatory effects of hemin were observed in the presence of detergents such as Lubrol-PX, and highly purified particulate enzyme could be activated to the same extent as enzyme in native membranes. These data suggest that the interaction of porphyrins with particulate guanylate cyclase is complex in nature and different from that with the soluble enzyme.

Animals↗
PubMed1984

Alterations in lung structure caused by inhalation of oxidants.

Morphometric and morphologic methods have been used to evaluate changes in rat lungs caused by the inhalation of a variety of oxidants. Exposure to 100% oxygen causes diffuse pulmonary injury and leads to death after 66-72 h of exposure. The primary insult leading to death in rats exposed to hyperoxia is injury to pulmonary capillary endothelium. Sublethal exposure to hyperoxia was found to cause diffuse injury to all major components of the alveolar septum and was associated with destruction of approximately 50% of the pulmonary capillary endothelial cells. A corresponding decrease in pulmonary capillary surface area and capillary lumen volume also occurred. Exposure to ozone and to nitrogen dioxide in low concentrations did not cause a diffuse injury throughout the alveolar region of the lung, but rather led predominantly to structural alterations in terminal bronchioles and in their adjacent alveoli. Morphometric evaluation of animals exposed to 0.25 ppm ozone and to 2 ppm NO2 demonstrated quantitatively and qualitatively similar lesions. These lesions primarily involve injury and remodelling of the alveolar epithelium. These changes in the alveolar epithelium were also associated with the recruitment of increased numbers of alveolar macrophages to the proximal alveolar region. The different types of lung injury caused by various oxidants are most likely to be related to differences in their reactivity with tissue components and to differences in concentration, distribution, and diffusion characteristics of the oxidant gases.

Animals↗
PubMed1984

The sequence of the gorilla fetal globin genes: evidence for multiple gene conversions in human evolution.

Two fetal globin genes (G gamma and A gamma) from one chromosome of a lowland gorilla (Gorilla gorilla gorilla) have been sequenced and compared to three human loci (a G gamma-gene and two A gamma-alleles). A comparison of regions of local homology among these five sequences indicates that long after the duplication that produced the two nonallelic gamma-globin loci of catarrhine primates, about 35 million years (Myr) ago, at least one gene conversion event occurred between these loci. This conversion occurred not long before the ancestral divergence (about 6 Myr ago) of Homo and Gorilla. After this ancestral divergence, a minimum of three more gene conversion events occurred in the human lineage. Each human A gamma-allele shares specific sequence features with the gorilla A gamma-gene; one such distinctive allelic feature involves the simple repeated sequence in IVS 2. This suggests that early in the human lineage the A gamma-genes may have undergone a crossing-over event mediated by this simple repeated sequence. The DNA sequences from coding regions of both G gamma- and A gamma-loci, a comparison of 292 codons in the corresponding gorilla and human genes, show an unusually low evolutionary rate, with only two nonsilent differences and, surprisingly, not even one silent substitution. The two nonsynonymous substitutions observed predict a glycine at codon 73 and an arginine at codon 104 in the gorilla A gamma-sequence rather than aspartic acid and lysine, respectively, in human A gamma. Because only arginine has been found at position 104 in gamma-chains of Old World monkeys, it may represent the ancestral residue lost in gorilla and human G gamma-chains and in the human A gamma-chain. Possibly the arginine codon (AGG) was replaced by the lysine codon (AAG) in the G gamma-gene of a common ancestor of Homo and Gorilla and then was transferred to the A gamma-gene by subsequent conversions in the human lineage. DNA sequence conversions, similar to that attributed to the fetal gamma-globin genes, appear to be relatively frequent phenomena and, if widespread throughout the genome, may have profound evolutionary consequences.

Alleles↗
PubMed1984

Pulmonary macrophage accumulation and asbestos-induced lesions at sites of fiber deposition.

Inhaled chrysotile asbestos fibers are deposited at alveolar duct bifurcations and subsequently are phagocytized there by pulmonary macrophages. The characteristics of the rapid macrophage response at alveolar duct bifurcations following asbestos inhalation has been further evaluated. Significant numbers of pulmonary macrophages accumulated at sites of asbestos deposition within 48 h after a 1-h exposure, whereas duct surfaces of sham-exposed animals were essentially devoid of macrophages. The influx of macrophages was associated with a significantly increased bifurcation tissue area (p less than 0.025), and this alteration persisted for at least 1 month. Two thirds of the accumulated macrophages from alveolar duct bifurcations could be removed by bronchoalveolar lavage. Macrophages recovered by lavage had significant changes (p less than 0.01) in their morphology and in their phagocytic and chemotactic capacities. These cellular alterations could play a role in the pathogenesis of asbestos-related lung disease.

Animals↗
PubMed1983

Highly purified particulate guanylate cyclase from rat lung: characterization and comparison with soluble guanylate cyclase.

Guanylate cyclase was purified 1000-fold from washed rat lung particulate fractions to a final specific activity of 500 nmoles cyclic GMP produced/min/mg protein by a combination of detergent extraction and chromatography on concanavalin A-Sepharose, GTP-agarose, and blue agarose. Particulate guanylate cyclase has a molecular weight of 200 000 daltons, a Stokes radius of 48 A and a sedimentation coefficient of 9.4 while the soluble form has a molecular weight of 150 000 daltons, a Stokes radius of 44 A, and a sedimentation coefficient of 7.0. Whereas the particulate enzyme is a glycoprotein with a specific affinity for concanavalin A and wheat germ agglutinin, the soluble form of guanylate cyclase did not bind to these lectins. Purified particulate guanylate cyclase did not cross-react with a number of monoclonal antibodies generated to the soluble enzyme. While both forms of the enzyme could be regulated by the formation of mixed disulfides, the particulate enzyme was relatively insensitive to inhibition by cystine. With GTP as substrate both forms of the enzyme demonstrated typical kinetics, and with GTP analogues negative cooperativity was observed with both enzyme forms. These data support the suggestion that the two forms of guanylate cyclase possess similar catalytic sites, although their remaining structure is divergent, resulting in differences in subcellular distribution, physical characteristics, and antigenicity.

Animals↗
PubMed1982

Ultrastructure and morphometric analysis of hypertrophic nucleoli in non-Hodgkin's lymphoma and phytohemagglutinin-stimulated lymphocytes.

The ultrastructure of hypertrophic nucleoli in large cells from each of 5 successive cases of non-Hodgkin's lymphoma (regardless of predominant cell type) showed irregularly rounded or ovoid, mostly compact forms with few scattered light spaces. Occasional nucleolonemal forms were noted. Few ring forms or transitional forms between ring and compact or nucleolonemal types were present. Granular components occupied 78.5 +/- 1.0% of the mean total area of 132 lymphoma large cell nucleoli of all configurations studied. Hypertrophic nucleoli in 27 phytohemagglutinin (PHA)-stimulated lymphocytes were predominantly nucleolonemal with 74.2 +/- 10.6% granular composition. The qualitative and quantitative distribution of nucleolar granular moieties did not vary significantly between individual cases of lymphoma nor quantitatively between these and nucleoli in PHA-stimulated lymphocytes. These observations lend further credence to the suggestion of the lymphocyte as a common progenitor cell type for the large B and T cell of malignant lymphomas. Some functional similarity of their nucleoli and those of PHA-stimulated lymphocytes in their participation in ribonucleic acid synthesis is implied. Generally compact nucleoli of lymphomas in contrast to nucleolonemal forms of PHA-stimulated lymphocytes may be pathognomonic for large lymphocytic cells undergoing neoplasia.

Cell Nucleolus↗
PubMed1981

[A follow-up survey on airborne fungal spore counts in the Taipei area (author's transl)].

The airborne fungal spore count was determined daily from 1975 to 1979 at six different stations in the Taipei Area. The count per year was 5656/cm2 in average. More than 75% of the spores could be identified microscopically and classified into 14 genera. The spore season was found from May to October in the Taipei Area. The count per month during this period reached 632/cm2. Only 311/cm2/month was found from November to April. Data collected from the six stations differed slghtly, the count was low in the city (4853/cm2/year) and high in the suburbs (8801/cm2/year). The counts were very close in the first four years (4325-4677/cm2/year), but dropped dramatically in the fifth year (2017/cm2/year). The spore count was influenced by temperature, humidity, rainfall as well as wind velocity. Among the 14 genera found by the slide method, six could not be isolated by the plate culture method. Other 24 genera isolated with plates did not appear on the slides.

Air Microbiology↗
PubMed1980

Stimulation of muscle glycogen synthase phosphatase by polyamines.

The naturally-occurring polyamines were found to stimulate glycogen synthase phosphatase from rat skeletal muscles. The sequence of effectiveness in the stimulation was spermine greater than spermidine greater than putrescine. It was shown that the spermine-sensitive phosphatase was present primarily in the soluble fraction of the muscle extract. In the presence of spermine, the phosphatase activity can be further stimulated by Mn2+; however, a lower Mn2+ concentration is required for the activation of the enzyme in comparison with that in the absence of spermine. Kinetic studies indicated that activation of glycogen synthase phosphatase by spermine was achieved by an increase in its V without significant alteration in the Km, suggesting that spermine directly stimulated the catalytic efficiencly of the phosphatase enzyme.

Animals↗
PubMed1980

Effects of insulin treatment on the activities of phosphoprotein phosphatase and its inhibitors.

An increase in glycogen synthase phosphatase (phosphoprotein phosphatase) activity was observed in the rat skeletal muscle extract following insulin administration. The phosphoprotein phosphatase activity present in the muscle extract from insulin treated rats was observed to remain elevated after the extract had been subjected to a molecular sieve chromatography. These results indicate that the stimulatory effects of insulin is due to modification of phosphatase itself or some macromolecular weight modifiers. The heat-stable protein inhibitors of the phosphoprotein phosphatase were isolated from skeletal muscle of insulin treated and control rats and their inhibitory potencies were compared over a wide range of protein concentrations. The inhibitory potency in the insulin treated rat skeletal muscle was found to be significantly less than that in the control muscle. Since type-1 inhibitor is well-known to be active only after being phosphorylated by cyclic AMP-dependent protein kinase, we suggest that the observed change in phosphoprotein phosphatase inhibitor potency is most likely mediated by an alteration in the phosphorylation state of type-1 inhibitor.

Animals↗
PubMedDate not supplied

Quantitative aspects of immunogold labeling in embedded and in nonembedded sections.

We tried to control immunolabeling conditions so that information about antigen concentration could be achieved by quantifying labeling patterns. Working with immunogold labeling procedures in ultrathin cryosections, we observed that differential penetration of immunoreagents causes considerable differences in labeling efficiency between various cell structures. Therefore, in these nonembedded sections, labeling densities can only be used to measure variations in antigen concentration within one cell structure. After embedding the tissue in 30% polyacrylamide (PAA), differences in penetration were negated. The equalizing effect of PAA on the labeling efficiency enabled us to design a simple immunocytochemical method by which concentrations of a protein can be measured in situ at subcellular levels, provided that no variations in the protein's structural conformation occur that would affect its immunoreactivity. In spite of a higher sensitivity observed for Ig-gold, we preferred to use protein A-gold in our system because of the low nonspecific labeling and the more precise antigen detection by the latter immunomarker.

Amylases↗
PubMedDate not supplied

Hydrogen peroxide release from alveolar macrophages and alveolar type II cells during adaptation to hyperoxia in vivo.

The effect of hyperoxia (1-14 days, 85% O2) on rat alveolar macrophage and alveolar type II cell oxidant and antioxidant characteristics was investigated. Unstimulated control macrophages (2 h ex vivo) released hydrogen peroxide at a rate of 3.5 +/- 1.3 nmol/min mg protein-1, which was a cyanide-sensitive process. H2O2 release from alveolar macrophages decreased slightly but not significantly after 1 day in hyperoxia and increased significantly after 3 days (180%, p less than .05) and 14 days (380%, p less than .01). When H2O2 release was expressed as nmol from total macrophages per animal, the increase after 14 days in hyperoxia was 760%. H2O2 generation by hyperoxic macrophages was cyanide resistant, indicating the involvement of active NADPH oxidase. In both control and hyperoxic macrophages H2O2 release could be significantly stimulated with phorbol myristate acetate (PMA). Comparisons of H2O2 release by freshly isolated alveolar macrophages and alveolar type II cells must be cautiously interpreted because some cell functions may change during the isolation procedure. Freshly isolated (6 h ex vivo) control alveolar type II cells were found to generate H2O2 at a rate of 0.26 +/- 0.05 nmol/min mg protein-1. In type II cells H2O2 release, calculated as nmol/mg protein, decreased during the first 7 days of hyperoxia to 10% (p less than .01) of the control value and then returned back up to the control level after 14 days. A similar decrease was observed if H2O2 release was calculated as nmol/cell number. H2O2 release from control and hyperoxic type II cells was cyanide sensitive. The decrease in H2O2 release in type II cells was associated with cell membrane injury (as assessed by electron microscopy), while biochemical markers of cellular injury (trypan blue exclusion and cellular high-energy phosphates ATP, ADP) were unchanged. The ability of type II cells to scavenge extracellular H2O2 did not change in acute hyperoxia, but it increased significantly during the second week in hyperoxia. These results indicate that macrophages but not type II cells are stimulated to produce H2O2 during prolonged exposure to hyperoxia.

Adaptation, Physiological↗
PubMedDate not supplied

Prevalence of Legionella pneumophila infection in children and its role in pediatric community-acquired atypical pneumonia.

The infection status of Legionella pneumophila in children and its role in pediatric community-acquired pneumonia were investigated. Because exposure to Legionella pneumophila may be highly variable and there has been no unanimously agreed-upon cut-off values in previous seroprevalence studies, 60 serum samples collected from infants aged 12 to 18 months were examined using immunofluorescence antibody test to determine the cut-off titer which represents past Legionella pneumophila infection. An IFA titer of greater than or equal to 32 was found to be suitable to represent past L. pneumophila infection. A seroepidemiological study of the prevalence of L. pneumophila in 180 children showed the prevalences in children aged 7 to 18 years to be between 28.4 and 35%. Fifty-three paired sera were tested to determine the role of Legionella pneumophila in pediatric, community-acquired, atypical pneumonia. The frequency of confirmed disease was 0% and of presumptive cases was 5.7%. Legionella pneumophila was not a common etiologic agent of pediatric pneumonia in Taiwan.

Adolescent↗