Biomedical subjects

E C Chang

Publications and source records attributed to E C Chang.

16 recordsLinked to original sources

PubMed1998

Irrational beliefs, optimism, pessimism, and psychological distress: a preliminary examination of differential effects in a college population.

The present study compared the effects of irrational beliefs measured by the Survey of Personal Beliefs (SPB) and optimism and pessimism as measured by the revised Life Orientation Test (LOT-R) on depressive and anxious symptoms 6 weeks later. Results of analysis of variances for both measures of psychological distress indicated a significant main effect for pessimism only. Implications for Ellis Rational Emotive Therapy are discussed.

Adult↗

PubMed1998

What makes dreams positive or negative: relations to fundamental dimensions of positive and negative mood.

The present study examined the general emotional content of dreams reported by individuals who typically experience "positive" versus "negative" dreams. Self-reports of the 153 participants indicated that positive versus negative dreamers (ns = 42 and 24, respectively) generally experienced more positive emotions, e.g., joviality, self-assurance, and fewer negative emotions, e.g., fear, sadness. No differences were found in the self-reports of the participants in the experience of surprise, guilt, fatigue, and shyness between the groups, hence, positive and negative dreams do not appear to reflect simply more positive and fewer negative emotions, respectively.

Adolescent↗

PubMed1998

Locus of control and the fundamental dimensions of moods.

The present study examined the association between locus of control and positive and negative moods in 253 college students. Using the PANAS-X, designed by Watson and Clark, individuals scoring high on internal locus of control also scored higher across different dimensions of positive mood. Conversely, individuals scoring high on external locus of control had higher scores across different dimensions of negative mood.

Adolescent↗

PubMed1997

The Multidimensional Dream Inventory: preliminary evidence for validity and reliability.

The present study focused on the development of the Multidimensional Dream Inventory, an individual difference measure of dimensions of dreams. Items were administered to 151 college students. Consistent with expectations, results of an exploratory factor analysis of intercorrelations among items indicated a four-factor solution was appropriate. As a result, four dream-relevant scales were constructed, viz, Dream Importance, Dream Vividness, Dream Usefulness, and Dream Recall. In addition, these scales showed good internal consistency for research. Implications and uses for the Multidimensional Dream Inventory were discussed.

Adaptation, Psychological↗

PubMed1996

Relations between problem orientation and optimism, pessimism, and trait affectivity: a construct validation study.

This study investigated the construct validity of the Positive and Negative Problem Orientation scales of the Social Problem-Solving Inventory-Revised (SPSI-R) by examining the relations between these scales and measures of optimism, pessimism, and trait affectivity. Consistent with expectations based on social problem-solving theory, positive problem orientation was found to have a relatively large amount of variance in common with optimism and positive affectivity, and negative problem orientation was found to share a large amount of variance with pessimism and negative affectivity, but not enough to be considered redundant in either case. Positive problem orientation was found to add significant incremental validity to the prediction of adaptive problem-engagement coping even after partialing out the variance associated with optimism and positive affectivity. In addition, negative problem orientation was found to add unique variance to the prediction of psychological distress even after controlling for pessimism and negative affectivity.

Adaptation, Psychological↗

PubMed1996

Signaling in the yeast pheromone response pathway: specific and high-affinity interaction of the mitogen-activated protein (MAP) kinases Kss1 and Fus3 with the upstream MAP kinase kinase Ste7.

Kss1 and Fus3 are mitogen-activated protein kinases (MAPKs or ERKs), and Ste7 is their activating MAPK/ERK kinase (MEK), in the pheromone response pathway of Saccharomyces cerevisiae. To investigate the potential role of specific interactions between these enzymes during signaling, their ability to associate with each other was examined both in solution and in vivo. When synthesized by in vitro translation, Kss1 and Fus3 could each form a tight complex (Kd of approximately 5 nM) with Ste7 in the absence of any additional yeast proteins. These complexes were specific because neither Hog1 nor Mpk1 (two other yeast MAPKs), nor mammalian Erk2, was able to associate detectably with Ste7. Neither the kinase catalytic core of Ste7 nor the phosphoacceptor regions of Ste7 and Kss1 were necessary for complex formation. Ste7-Kss1 (and Ste7-Fus3) complexes were present in yeast cell extracts and were undiminished in extracts prepared from a ste5delta-ste11delta double mutant strain. In Ste7-Kss1 (or Ste7-Fus3) complexes isolated from naive or pheromone-treated cells, Ste7 phosphorylated Kss1 (or Fus3), and Kss1 (or Fus3) phosphorylated Ste7, in a pheromone-stimulated manner; dissociation of the high-affinity complex was shown to be required for either phosphorylation event. Deletions of Ste7 in the region required for its stable association with Kss1 and Fus3 in vitro significantly decreased (but did not eliminate) signaling in vivo. These findings suggest that the high-affinity and active site-independent binding observed in vitro facilitates signal transduction in vivo and suggest further that MEK-MAPK interactions may utilize a double-selection mechanism to ensure fidelity in signal transmission and to insulate one signaling pathway from another.

Base Sequence↗

PubMed1996

Preliminary study of health value as a moderator of the link between age and life satisfaction.

In the present study of the influence of health value as a potential moderator of age and life satisfaction. 157 undergraduate students (M = 20.8 yr.) completed a battery in which they provided demographic information and completed a number of different self report measures, including the Satisfaction With Life Scale and the Health Value Scale. A 2 (younger vs older) x 2 (high vs low health value) analysis of variance with life satisfaction as the dependent variable showed a significant man effect for health value and a significant interaction between age and health value but no man effect for age. These findings support health value as a moderator of the relation between age and psychological well-being. Implications for research and practice are discussed.

Adolescent↗

PubMed1996

How the value of health moderates the link between age and depressive symptoms: further evidence.

To extend earlier findings, this pilot study explored the role of self-reported value of health as a moderator between age and scores on the Beck Depression Inventory. 157 undergraduate students completed the Health Value Scale and the Beck inventory. There was no significant main effect for age with scores on the Beck inventory; however, scores on the Health Value Scale and their interaction with age were significant contributors to scores on the Beck Depression Inventory. These results are consistent with earlier findings. Implications for research and development are discussed.

Adolescent↗

PubMed1994

Cooperative interaction of S. pombe proteins required for mating and morphogenesis.

We isolated two S. pombe genes, scd1 and scd2, that are required for normal morphology and mating. scd1 and scd2 are homologous to CDC24 and BEM1, respectively, of S. cerevisiae. Epistasis analyses indicate that scd2 and ras1 converge upon scd1, which, in turn, interacts with cdc42sp, a RHO-like GTPase. Studies with the yeast two-hybrid system indicate that scd2 forms complexes with both scd1 and cdc42sp. Furthermore, biochemical studies indicate that the interaction between scd1 and scd2 is direct. The yeast two-hybrid data further suggest that scd1, scd2, cdc42sp, and ras1, in its GTP-bound state, act cooperatively to form a protein complex.

Adaptor Proteins, Signal Transducing↗

PubMed1991

Genetic and biochemical characterization of Cu,Zn superoxide dismutase mutants in Saccharomyces cerevisiae.

The allele scd 1 is a recessive chromosomal mutation in Saccharomyces cerevisiae that eliminates Cu,Zn superoxide dismutase (SOD-1) activity. SOD-1- strains are unable to grow in 100% O2 in rich medium and are methionine and lysine auxotrophic when grown in air (Bilinski, T., Krawiec, Z., Liczmanski, A., and Litwinska, J. (1985) Biochem. Biophys. Res. Commun. 130, 533-539). In this report, scd1 was genetically mapped to the right arm of chromosome X, 11 centimorgans proximal to cdc11. The gene for SOD-1 (SOD1) was physically mapped by Southern blot to restriction fragments containing CDC11. scd1 failed to complement a complete deletion of SOD1. Thus, scd1 maps to the SOD1 locus and is designated sod1-1. The molecular basis for the lack of SOD-1 activity in sodl-1 carrying strains has also been established. The size and amount of SOD-1 mRNA in the mutant were essentially the same as in wild type cells. Western blot analysis showed that the SOD-1 dimer and 16-kilodalton subunit that co-migrated electrophoretically with wild type yeast SOD-1 were abundant in mutant cell extracts. However, two additional SOD-1 immunoreactive polypeptides were detected in these extracts in both denaturing and nondenaturing gels. None of the SOD-1 immunoreactive species in the mutant extracts exhibited superoxide dismutase activity. Transformants of the mutant strain carrying episomal, wild type SOD1 expressed wild type, active SOD-1 protein, indicating that the mutant allele had no discernible effect on the correct synthesis and activation of apoSOD-1. Size exclusion chromatography of soluble cell extracts derived from wild type and SOD1 deletion strains identified a copper binding peak that corresponded to SOD-1. This copper-binding fraction was absent in cell extracts from the sod1-1-containing strain although Western blot analysis of the corresponding chromatographic fractions showed that SOD-1 polypeptide was present in these fractions. Sequence data derived from the cloned genes showed that sod1-1 differed from SOD1 only in the adjacent 5'-noncoding region. The biochemical data indicate that this genetic alteration results in the synthesis of a collection of SOD-1 polypeptides that fail to bind copper and may also fail to completely self-associate. Both phenotypes could be due to the inability of these polypeptides to adopt the native SOD-1 conformation.

Alleles↗

PubMed1991

Subcutaneous fascioliasis: a case report.

A 32-year old housewife, living in Seoul, recognized incidentally a painless mass at the left chest wall. During later 3 months, she experienced spontaneous swelling and regression of the mass repeatedly for 4 times. Surgical resection showed a granuloma at anterior serratus muscle containing a nearly matured adult of Fasciola species without vitellaria and uterus. This is the 11th human fascioliasis and the first extra-abdominal infection reported in Korea.

Adult↗

PubMed1990

O2-dependent methionine auxotrophy in Cu,Zn superoxide dismutase-deficient mutants of Saccharomyces cerevisiae.

Mutant strains of the yeast Saccharomyces cerevisiae which lack functional Cu,Zn superoxide dismutase (SOD-1) do not grow aerobically unless supplemented with methionine. The molecular basis of this O2-dependent auxotrophy in one of the mutants, Dscd1-1C, has been investigated. Sulfate supported anaerobic but not aerobic mutant growth. On the other hand, cysteine and homocysteine supported aerobic growth while serine, O-acetylserine, and homoserine did not, indicating that the interconversion of cysteine and methionine (and homocysteine) was not impaired. Thiosulfate (S2O3(2-] and sulfide (S2-) also supported aerobic growth; the activities of thiosulfate reductase and sulfhydrylase in the aerobic mutant strain were at wild-type levels. Although the levels of SO4(2-) and adenosine-5'-sulfate (the first intermediate in the SO4(2-) assimilation pathway) were elevated in the aerobically incubated mutant strain, this condition could be attributed to a decrease in protein synthesis caused by the de facto sulfur starvation and not to a block in the pathway. Therefore, the activation of SO4(2-) (to form 3'-phosphoadenosine-5'-phosphosulfate) appeared to be O2 tolerant. Sulfite reductase activity and substrate concentrations [( NADPH] and [SO3(2-)]) were not significantly different in aerobically grown mutant cultures and anaerobic cultures, indicating that SOD-1- mutant strains could reductively assimilate sulfur oxides. However, the mutant strain exhibited an O2-dependent sensitivity to SO3(2-) concentrations of less than 50 microM not exhibited by any SOD-1+ strain or by SOD-1- strains supplemented with a cytosolic O2(-)-scavenging activity. This result suggests that the aerobic reductive assimilation of SO4(2-) at the level of SO3(2-) may generate a cytotoxic compound(s) which persists in SOD-(1-) yeast strains.

Aerobiosis↗

PubMed1989

Intracellular Mn (II)-associated superoxide scavenging activity protects Cu,Zn superoxide dismutase-deficient Saccharomyces cerevisiae against dioxygen stress.

Three Cu,Zn superoxide dismutase (SOD-1)-deficient Saccharomyces cerevisiae mutants do not grow in 100% O2 in rich medium and require Met and Lys when grown in air (Bilinski, T., Krawiec, Z., Liczmanski, A., and Litwinska, J. (1985) Biochem. Biophys. Res. Commun. 130, 533-539). We show herein that medium manganese (II) accumulated by the mutants rescues these O2-sensitive phenotypes; 2 mM medium Mn2+ represented the threshold required for cell growth. The accumulation of Mn2+ was not oxygen-inducible since mutants grown aerobically and anaerobically accumulated the same amount of Mn2+. Mn2+ accumulation is not unique to these mutants since wild type accumulated almost twice as much Mn2+ as did mutant. ESR spectra of the cell extracts and whole cells loaded with Mn2+ were typical of free Mn(II) ion. These spectra could not account quantitatively for the total cellular Mn2+, however. A screen for soluble antioxidant activities in the Mn2+-supplemented cells detected O2- (superoxide) scavenging activity, with no change in catalase or peroxidase activities. This O2- scavenging activity was CN- and heat-resistant. No achromatic bands were revealed in nondenaturing gels of Mn2+- containing cell extracts stained for O2- scavenging activity. The Mn2+-dependent O2- scavenging activity in the cell extracts was quenched by EDTA and dialyzable. More than 60% of both the intracellular Mn2+ and the O2- scavenging activity was removed by 2-h dialysis. Dialyzed cells were not viable in air unless resupplemented with either Met or Mn2+. Although Mn2+ supported the aerobic growth of these mutants, excess Mn2+, which correlated with an elevated O2- scavenging activity, was toxic to both mutant and wild type. The results indicate that free or loosely bound Mn2+ ion protects the mutants against oxygen stress by providing an intracellular, presumably cytosolic, O2- scavenging activity which replaces the absent SOD-1.

Alleles↗

PubMed1989

Arsenic oxide-induced thermotolerance in Saccharomyces cerevisiae.

The growth response of Saccharomyces cerevisiae to arsenite and arsenate and the relationship between the enhancement of heat shock protein (hsp) synthesis caused by these arsenic oxides and thermotolerance are reported. Arsenite and arsenate transiently inhibited cell growth and overall protein synthesis; arsenate enhanced the synthesis of the 42-, 74-, 84-, and 100-kilodalton hsps, whereas arsenite enhanced synthesis of only the 74-kilodalton hsp. The induction of these hsps reached a maximum 45 min following metal oxide treatment and then declined. A delayed thermotolerance peaked 4 h after metal oxide addition, at which time cell growth and protein synthesis were recovering. These data show that the arsenate- and arsenite-induced thermotolerance in S. cerevisiae cells does not appear to be causally related to either hsp synthesis or cell cycle arrest.

Arsenates↗

PubMed1987

Placental-derived mitogenic factor for human fetal adrenocortical cell cultures.

The human fetal adrenal cortex is one of the largest fetal organs and synthesizes precursors for placental estrogen production as part of the feto-placental unit. The factors controlling the rapid growth of the human fetal adrenal cortex during the second and third trimesters are not known. Placental regulation of the growth of human fetal adrenocortical cell cultures from second trimester fetuses was studied. A placental-derived mitogenic factor (PDMF) was detected in tissue homogenates of 14 to 22 week human placentas and stimulated adrenocortical cell number and [3H]thymidine incorporation into DNA 5-8 fold. PDMF has been partially purified by ammonium sulfate precipitation and anion exchange chromatography. PDMF is a heat sensitive protein with disulfide bonds required for activity. The growth stimulation by PDMF was significantly greater than that for basic or acidic fibroblast growth factor by 25-50% and epidermal growth factor by 3-4 fold. The placental hormones, progesterone, estriol, estradiol, placental lactogen and chorionic gonadotropin, either alone or in combination did not stimulate fetal adrenocortical cell growth, except for a 41% cell number increase by progesterone. Platelet-derived growth factor and insulin-like growth factors I and II were not mitogenic for these cells. These results show that the placenta contains a potent growth factor for human fetal adrenocortical cell cultures. This implies a direct role for the placenta in control of this fetal organ's growth, which would make the human feto-placental unit a bi-directional relationship.

Adrenal Cortex↗

PubMed1980

Lymphocytes and urine in ceroid lipofuscinosis.

Pathognomonic ultrastructural inclusions were found in the lymphocytes of 16 patients with neuronal ceroid lipofuscinosis (Batten's disease) and in the urine of three of four of such patients. These inclusions remained type specific for each patient and were identical with deposits in nerve cells and other body tissues. They persisted in lymphocytes in short-term tissue culture, but disappeared with stimulation by phytohemagglutinin. Siblings had identical inclusions. None were present in heterozygotes. Examination of lymphocytes in the peripheral blood cells is an easy method to use in the diagnosis of ceroid lipofuscinosis, but it cannot be used to detect carriers.

Adolescent↗