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Biomedical subjects

K H Yang

Publications and source records attributed to K H Yang.

At least 127 records · Page 7Linked to original sources
PubMed1991

Solitary myeloma with massive extracellular crystalline structures--a case report.

We describe a case of solitary myeloma showing cystic change filled with massive crystalline structures in a 54-year-old woman. A bone X-ray showed a solitary cystic osteolytic lesion in the right iliac bone. Serum and urine protein electrophoresis showed no demonstrable M-protein, and bone-marrow aspirates did not show any myeloma cells. Histologic examination of the tumor revealed aggregation of plasma cells with massive extracellular infiltration of the rhomboid-shaped crystalline structures. In immunoperoxidase staining, both these crystalline structures and the cytoplasms of the myeloma cells demonstrated a positive reaction for lambda light chain. By electron microscope, the large extracellular crystalline structures were observed, and we found unique rhomboid or rectangular-shaped crystalline structures in the cytoplasms of the myeloma cells.

Bone Neoplasms↗
PubMed1990

Regulation of the hydrolytic and transfer activities of gamma-glutamyl transpeptidase.

The activity of gamma-glutamyl transpeptidase was inhibited and stimulated by hippurate with and without acceptor molecules, respectively. Substrate activation was observed when acceptor molecules was not present but the activation was disappeared by the addition of hippurate. When glutamine was absent the inhibition degree of hippurate at pH 8.0 was greater than at pH 7.0, whereas in the presence of both hippurate and glutamine the results were opposed. These show a possibility that glutaminase is activated by hippurate under the condition of physiological pH. The activation of glutaminase by hippurate was also confirmed directly. The inhibition degree of transfer activity by glutamine was increased along the increase of acceptor concentration only in the presence of hippurate. Gamma-Glu-Phe-Gly satisfying prerequisites for donors doesn't act as a substrate, which shows that L-gamma-glutamyl-p-nitroanilide itself hardly acts as an acceptor. This contradicts to an idea that substrate activation caused by autotranspeptidation. The change of apparent Km and Vmax according to the change of pH in the presence of hippurate was different from that in the presence of acceptors. This shows a possibility that the active site on small subunit is inhibited and the latent active site in large subunit is exposed by the interaction of hippurate to the enzyme.

Animals↗
PubMed1990

High-level expression of human insulin-like growth factor II in Escherichia coli.

A gene encoding mature human insulin-like growth factor II (IGF-II) was constructed from the modified IGF-II cDNA sequence and two double-stranded synthetic oligodeoxynucleotide linkers. It was fused to a truncated lacZ gene such that IGF-II was expressed as part of C-terminus of beta-galactosidase. This fused lacZ'-IGF-II gene was under the control of tac promoter and we overproduced the beta-galactosidase-IGF-II fusion protein in the Escherichia coli. The fusion protein formed inclusion bodies inside the cells. The fusion protein was purified from the isolated inclusion bodies and IGF-II protein was obtained from their fusion protein by CNBr cleavage. The released IGF-II was confirmed by its molecular weight as determined by SDS-PAGE and by its ability to bind anti-IGF antibody.

Amino Acid Sequence↗
PubMed1990

Binding of Clostridium botulinum type B toxin to rat brain synaptosome.

Purified toxin and its subunits from Clostridium botulinum type B were labeled with 125iodine and binding of them to rat brain synaptosomes was studied. Labeled toxin and heavy chain were shown to bind to synaptosomes and there was no significant difference in the molar quantity of bound toxin and heavy chain at several concentrations of synaptosomes, whereas labeled light chain did not bind to synaptosomes. The binding of labeled heavy chain to synaptosomes was inhibited by unlabeled toxin and heavy chain to a similar degree as that of labeled toxin. The binding of labeled toxin and heavy chain to synaptosomes were inhibited by a monoclonal antibody which is specific for the heavy chain.

Animals↗
PubMed1990

Chronological changes in genetic variance and heritability of anthropometric characteristics among Chinese twin infants.

In order to examine the chronologic changes in genetic variance and heritability of anthropometric characteristics of Chinese infants in Taiwan, a total of 521 pairs of same-sexed twin neonates given birth in four major general teaching hospitals in Taipei City were studied. Based on the placental pattern and 12 red blood cell antigens, 428 MZ and 93 DZ twin pairs were identified and followed up to the age of one year. There was no significant genetic variance for all anthropometric characteristics adjusted for sex and gestational week before the age of six months. After adjusting for sex and gestational week, a significant genetic variance was observed at the age of six months, with heritability values of 0.51 (weight), 0.63 (head circumference), 0.77 (chest circumference), and 0.53 (arm circumference), as well as at one year, although with considerably lower heritability values. This implies that growth is dynamically determined by both genetic and environmental factors during infancy.

Age Factors↗
PubMed1990

Genetic variance and heritability of temperament among Chinese twin infants.

In order to examine the genetic variance and heritability of temperament among Chinese infants in Taiwan, a total of 62 pairs of same-sexed twin infants given birth in four major general teaching hospitals in Taipei City were studied. Based on placentation and 12 red blood cell antigens, 44 MZ and 18 DZ pairs were identified. Temperament was assessed at the age of six months by the Chinese edition of Carey's Temperament scale. Significant genetic variance was observed for activity level, approach or withdrawal, intensity of reaction, quality of mood, and threshold of responsiveness, with a heritability of 0.64, 0.56, 0.74, 0.39, and 0.45, respectively. There was no significant intrapair difference in temperamental characteristics between monochorionic and dichorionic MZ twins.

Female↗
PubMed1990

Chronological changes in genetic variance and heritability of systolic and diastolic blood pressure among Chinese twin neonates.

In order to examine the chronological changes in genetic variance and heritability of arterial systolic and diastolic blood pressure (SBP and DBP of Chinese infants in Taiwan, a total of 339 same-sexed twin neonates born in four major general teaching hospitals in Taipei City were studied. Based on placentation and 12 red blood cell antigens, 274 monozygotic (MZ) and 65 dizygotic (DZ) twin pairs were identified and followed up to the age of one year. Both SBP and DBP were measured by Doppler blood pressure monitor. Within-pair mean squares of SBP and DBP were consistently smaller in MZ than DZ twins at ages one month and over. The findings remained unchanged after the adjustment for the effects of age, sex, gestational age, placentation and physical state during blood pressure measurement. Falconer's heritability indices for adjusted SBP and DBP at ages two months and over ranged from 0.29 to 0.55 and from 0.27 to 0.45, respectively. The study indicates an important genetic influence on blood pressure during infancy.

Blood Pressure↗
PubMed1990

Genetic variance and heritability of serum cholesterol and triglycerides among Chinese twin neonates.

In order to examine the genetic variance and heritability of serum total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglycerides, a total of 349 pairs of same-sexed twin neonates born in four major general teaching hospitals in Taipei City were studied. Based on the placental pattern and 12 red blood cell antigens, 271 monozygotic (MZ) and 78 dizygotic (DZ) twin pairs were identified. There was a significant genetic variance for total cholesterol, HDL-C, LDL-C, and triglycerides both unadjusted and adjusted for sex, gestational age and placentation. The unadjusted heritability of total cholesterol, HDL-C, LDL-C, and triglycerides was 0.59, 0.30, 0.25 and 0.75, respectively; while the corresponding adjusted heritability was 0.74, 0.38, 0.31, and 0.49, respectively. Intrapair variance of serum lipids was not significantly different between monochorionic and dichorionic MZ twins.

China↗
PubMed1990

A dynamic finite element analysis of impulsive loading of the extension-splinted rabbit knee.

A dynamic nonlinear finite element model was developed to study juxtarticular stresses in the splinted rabbit knee, an established laboratory model for creating osteoarthrosis due to impulsive loading. Plane strain finite element results were validated by comparison with corresponding experimental data. Parametric effects studied included the input tibial displacement speed, the local bone density distribution, and the modulus of cartilage and subchondral bone. While the computed resultant contact force magnitude was sensitive to a number of model parameters, the stress patterns, when normalized to a given resultant force magnitude, were not. Despite comparable force peaks, the finite element results showed approximately six-fold higher effective strain rate levels for a severely impulsive loading protocol known to induce rapid osteoarthrosis, versus those for a mildly impulsive loading protocol not usually associated with cartilage damage. A propensity for elevated shear in the deep cartilage layer near the contact periphery, observed in nearly all computed stress distributions, is consistent with previous experimental findings of fissuring at that level in the impulsively loaded rabbit knee.

Animals↗
PubMed1990

An experimental study on prevention of postlaminectomy scar formation.

In repeat lumbar surgery for failed back syndrome, well organized fibrous scar tissue is often noted, binding together the dura, nerve roots, and paraspinal muscles. An animal experimental study was done to investigate the prevention of scar formation after lumbar laminectomy by using dacron and sodium hyaluronate. The experimental animals consisted of three groups: 1) control group, 2) D group (covering the laminectomy defect with dacron sheet), and 3) H group (covering the laminectomy defect with sodium hyaluronate gel). Animals were sacrificed at varying intervals (3-12 weeks) and the lumbar spines were evaluated with histologic preparations. Scar adhesion to the dura was most significantly suppressed in the D group, followed by the H group and the control group.

Animals↗
PubMed1989

Parental occupational lead exposure and lead concentration of newborn cord blood.

The purpose of this study was to determine the influence of parental occupational lead exposure on the lead levels of newborn cord blood in the Taipei area. From September 1984 to June 1985, 5,000 pregnant women voluntarily participated in the study at the Taipei Municipal Maternal and Child Hospital. Each woman was interviewed regarding her and her husband's occupational exposures; 2,948 successfully delivered healthy newborns, and cord blood samples were obtained using Terumo Venoject, and 242 samples were analyzed by graphite furnace atomic absorption spectrometry using an Instrumentation Laboratory 251 instrument. Nine cord blood samples were from newborns with both parents exposed, 26 samples had maternal exposure only, 105 samples had paternal exposure only, and 102 were nonexposed. The results showed that the average lead level of cord blood with both parents exposed was 8.9 +/- 2.9 micrograms%, maternal exposure 9.0 +/- 3.8 micrograms%, paternal exposure 8.3 +/- 3.4 micrograms%, and 6.9 +/- 3.2 micrograms% in the nonexposed group. There were significant differences between the nonexposed and the maternal exposure groups, and also between the nonexposed and paternal exposure groups. All 26 maternal exposures were from lead soldering operations. Multivariate analysis revealed that, after control of father's exposure status, newborn cord blood lead level increased 0.27 micrograms% for each hour the mother spent on lead soldering during a normal working day, thus suggesting that soldering during pregnancy may be hazardous to newborns. Paternal contribution to the cord blood lead levels seemed to be through either working at home with the pregnant mother also at home or bringing work clothes home for laundering.

Adolescent↗
PubMed1989

Postpartum subsidence of hepatitis B viral replication in HBeAg-positive carrier mothers.

To elucidate the effects of pregnancy and delivery on hepatitis B e antigen (HBeAg)-positive carrier mothers, 31 HBeAg-positive carrier mothers were followed-up postpartum 1 year, with 30 HBeAg-positive nonpregnant female carriers as controls. Serum hepatitis B surface antigen (HBsAg), HBeAg titer, and hepatitis B virus (HBV)-DNA concentration were studied at defined intervals. The results revealed that in the control group HBeAg titers and HBV-DNA concentrations fluctuated, whereas the HBsAg titers showed little change, but HBeAg clearance or seroconversion to anti-HBe were not noted on follow-up. In contrast, one carrier mother seroconverted to anti-HBe during pregnancy and the antibody persisted thereafter. Five of the remaining 30 carrier mothers cleared HBeAg postpartum, and among these five cases, one also seroconverted to anti-HBe. In addition, in another five of the 30 cases, the HBV-DNA fell to undetectable level (less than 0.04 ng/ml). All these ten cases had a common tendency of showing a decrease in HBeAg titers and/or HBV-DNA concentrations 1-2 months after delivery. The HBeAg titers and HBV-DNA concentrations in the other 11 cases remained unchanged, whereas the remaining nine cases had increased levels. It is concluded that subsidence of HBV replication is precipitated by delivery in one-third of HBeAg-positive carrier mothers in Taiwan, and this occurs most frequently 1-2 months postpartum.

Adult↗
PubMed1989

Experimental verification of facet load transmission by direct measurement of facet lamina contact pressure.

This paper presents results of a new measuring technique by means of which facet tip contact pressure data were obtained. The aim of the paper is to demonstrate by direct measurement the existence of a load transmission mechanism through the facet joint. Six lumbar spine motion segments were used in 21 tests. Simulated extensor muscle action was provided to overcome moments due to eccentric loads which represented body weight and an external hand-held load acting 340 mm anterior to the center of the disc. Facet pressure was measured in all cases when muscle load was applied to counteract body weight. This pressure increased when more muscle force was applied to balance the externally applied flexion moment. When the anterior load was released suddenly, there was a large increase in facet pressure with a concomitant decrease in disc pressure.

Adult↗
PubMed1989

Production of DNA single-strand breaks in unstimulated splenocytes by dimethylnitrosamine.

In an attempt to elucidate the mechanism whereby primary hepatocytes, but not liver S9 homogenates, generate immunosupprssive metabolites of dimethylnitrosamine (DMN), the production of DNA single-strand breaks (SSB) in unstimulated splenocytes was investigated with alkaline-elution analysis. Both hepatocytes and S9 homogenates induced SSB in cultured splenocytes by DMN - minimum detectable doses with the two metabolic activation systems (MAS) were 1 microM and 5 mM, respectively. DNA elution profiles were linear in splenocytes co-cultured with DMN and hepatocytes and convex in splenocytes incubated with DMN and S9 homogenates. Aminoacetonitrile (AAN; 10 mM), a DMN demethylase inhibitor, reversed SSB in splenocytes when incubated with either MAS. Addition of exogenous calf-thymus DNA to the hepatocyte co-culture medium did not affect the production of SSB. Rocking the hepatocyte-splenocyte cultures changed the elution profile from linear to convex. All of these treatments have been previously shown to block the immunosuppression by DMN in the hepatocyte co-culture system. These results indicate that the immunosuppression by DMN is not related to DNA damage, as measured by the production of SSB, and suggest that the metabolism of DMN to intermediates capable of producing genotoxicity and immunotoxicity may be qualitatively and/or quantitatively different.

Acetonitriles↗
PubMed1989

The effects of altered strain environments on bone tissue kinetics.

This study defines the alteration in bone tissue kinetics responsible for the "adaptive remodeling" response to altered strain environments. Adult beagle dogs were separated into three experimental groups: ulnar osteotomy, ulnar osteotomy with fracture fixation plate spanning the gap and sham surgery. Four sets of double fluorochrome labels were administered. Prior to sacrifice at 1, 3, and 6 months, strains were measured through rosette strain gages on the cranial and caudal surfaces of the intact radius. Histomorphometric analysis indicated that the increased bone mass in response to elevated strain results from increased activation frequency of modeling with more sites undergoing formation processes than resorption processes on periosteal and endocortical surfaces. Increased remodeling activation did not lead to increased bone mass. There was no evidence that elevated strain changes the individual vigor of osteoclasts or osteoblasts, or that the sigma period was altered by elevated strain.

Adaptation, Physiological↗
PubMed1989

Skeletal change in response to altered strain environments: is woven bone a response to elevated strain?

Studies demonstrate that geometric changes in bone architecture in response to altered mechanical strain occur through the formation of woven bone. The goal of this study was to test the hypothesis that these changes are partly the result of surgical manipulation rather than a true adaptive response to altered strain. Beagle dogs were subjected to either an ulnar osteotomy, an osteotomy with plate fixation, or sham operation. Strains on the radius were measured just prior to sacrifice 1, 3 or 6 months after surgery. Our results support the idea that woven bone can be a normal response to an abnormal strain environment if the mechanical challenge is intense enough; that elevated mechanical strains can cause the endocortical bone envelope to revert to a state of net formation; and that "adaptive remodeling" in adults in response to a change in mechanical strain may be a special case of modeling in which resorption is not required prior to formation at a particular skeletal site.

Adaptation, Physiological↗
PubMed1989

Clinical significance of the immunological tests in rheumatoid arthritis.

Of the many theoretical causes of rheumatoid arthritis(RA), the most widely held theory is the autoimmune mechanism. In order to clarify the clinical significance of the immunological tests in RA, we studied immunoglobulin and complement levels in sera and synovial fluids of 118 RA patients and the following results were obtained. 1) The levels of immunoglobulins were elevated in both serum and synovial fluid and this was more prominent in the seropositive cases than the seronegative ones. 2) The levels of C3 component were decreased in both serum and synovial fluid, while those of C4 were decreased only in synovial fluid. Serum C3 and C4 component levels were more decreased in the seropositive cases than the seronegative ones. 3) The immunoglobulin levels in serum (IgG, IgM and IgA) and synovial fluid (IgG and IgA) and the levels of C3, C4 component in serum were well correlated with the clinical forms of rheumatoid arthritis. 4) The IgA level in serum and IgM level in synovial fluid were more increased in the exacerbated cases than the chronic ones. 5) Serum IgG level was decreased after steroid medication over one month.

Arthritis, Rheumatoid↗