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Biomedical subjects

Y G Kim

Publications and source records attributed to Y G Kim.

At least 127 records · Page 7Linked to original sources
PubMed1993

Evolutionary stability in the asymmetric war of attrition.

It is shown that there are at least two evolutionarily stable strategies, or ESSs, in the war of attrition with a role asymmetry when players make an error with a small but positive probability in implementing their strategy choices. This result proves Maynard Smith's original conjecture that players should choose asymmetric pure strategies in the asymmetric war of attrition. It is also in contrast to the standard non-existence result of an ESS in this game under complete information. To derive this result we discretize the original game and apply the limit ESS condition introduced by Selten. The result is also compared with other evolutionary analyses of this game.

Animals↗
PubMed1993

Decreased acetylation of isoniazid in chronic renal failure.

Pharmacokinetic parameters of isoniazid obtained from 37 normal subjects were compared with parameters obtained from 14 patients with chronic renal failure. In the 29 normal rapid acetylators and eight normal slow acetylators, the mean plasma half-life values of isoniazid were 1.54 +/- 0.31 and 3.68 +/- 0.59 hours, respectively. The plasma half-life values of isoniazid in patients with chronic renal failure varied widely from 1.30 to 10.13 hours, but the values were significantly longer than those of normal subjects. Because isoniazid clearance is governed mainly by hepatic metabolism, such a significant prolongation of plasma half-life of isoniazid was unexpected; thus the pharmacokinetics of isoniazid were reevaluated in the same patients with chronic renal failure after the kidney transplantation. After successful kidney transplantation, the shortening of isoniazid half-life was pronounced and the nonrenal clearance was markedly increased. These findings indicate that decreased isoniazid clearance in chronic renal failure is caused in minor part by the decreased renal excretion of isoniazid and in major part by the depressed hepatic N-acetylation of isoniazid.

Acetylation↗
PubMed1993

Localization of Hantaan viral envelope glycoproteins by monoclonal antibodies in renal tissues from patients with Korean hemorrhagic fever H.

The role of viruses in several renal diseases is not documented clearly. The authors attempted to localize envelope glycoproteins of Hantaan virus in biopsy specimens from patients with Korean hemorrhagic fever (KHF) as evidence of direct viral invasion of renal tissues. The authors studied sequential sections of kidney biopsy specimens from 23 of 35 patients with serologically confirmed KHF diagnosed between June 1985 and December 1989. The sections were stained with the avidin-biotin-peroxidase complex method with monoclonal antibodies to G1 and G2 envelope glycoproteins. Control antibodies of the same isotype were used to rule out nonspecific staining, and hyperimmune rabbit sera or convalescent sera of patients with KHF were used for blocking tests. Normal renal tissues and kidney biopsy tissues from minimal-change nephrotic syndrome were used as negative control sections. The kidney biopsies were performed between the fifth and thirtieth days after onset of fever. The authors detected viral glycoproteins in renal tissues from 22 of the 23 patients. The viral glycoproteins were localized in the cytoplasm of the tubular epithelial cells, and the distribution of viral glycoproteins in the tubules was focal. Glycoproteins also were localized in the cytoplasm of the sloughed renal tubular epithelial cells, where tubular degenerative changes were prominent. These findings suggest the direct invasion of renal tubules by the virus and may partly explain the pathogenesis of acute renal failure in KHF.

Adolescent↗
PubMed1993

Black heel with atypical melanocytic hyperplasia.

Two cases with a black pigmented patch on the heel are reported. Biopsy specimens showed that atypical melanocytic hyperplasia was confined to the epidermis despite the lesion being present for a long time. The diagnosis of atypical melanocytic hyperplasia should be considered in the differential diagnosis of the black heel.

Adult↗
PubMed1993

Studies on isosporosis in dogs. I: Isolation and sporulation of Isospora ohioensis.

Based on the morphologic characteristics of oocysts of the genus Isospora, we have demonstrated that I. ohioensis is a relatively common Isospora species in dogs which are resident in Chonbuk province, Korea. The prepatent period of I. ohioensis was four days. The size of the unsporulated oocysts in fresh stool specimens was 22.9 x 19.8 microns (R = 1.16). The size of the contracted sporonts was 17.4 x 16.3 microns (R = 1.06). By 96 hours, sporulation is complete and the ratio of length/width was constant relatively. And the sizes of oocysts and sporocysts were 22.8 x 20.5 microns (R = 1.11) and 15.0 x 10.8 microns (R = 1.39), respectively. At this time it is most reliable for the measurements of oocyst sizes of I. ohioensis to provide with the identifiable clues against the others. It is therefore recommended that the clinical fecal specimens suspected of isosporosis should first be incubated and aerated for 96 hours before a definitive parasitological diagnosis can be reached. These and other observations contribute to the understanding of the biological characteristics and laboratory and clinical diagnosis of isosporosis.

Animals↗
PubMed1992

Overproduction, purification and characterization of M.HinfI methyltransferase and its deletion mutant.

We have used the polymerase chain reaction to alter transcriptional and translational signals surrounding the hinfIM gene [encoding M.HinfI methyltransferase (MTase)] so as to achieve overexpression in Escherichia coli. The PCR-generated hinfIM gene was subcloned in a high-expression vector under control of the hybrid trp-lac promoter. In addition, the positive retroregulator stem-loop sequence derived from the crystal protein-encoding gene of Bacillus thuringiensis was inserted downstream from hinfIM. Using a similar approach, we have also constructed overproducer clones of a deletion mutant of M.HinfI MTase that has 97 amino acids from the C terminus deleted. The plasmid from the mutant clones is fully protected from HinfI restriction endonuclease digestion. It appears that the functional properties (the recognition and catalytic functions) are encoded within this mutant gene. The overproducer clones yield the wild type (wt) and the mutant enzymes to about 10% of total cellular protein upon induction with 1 mM IPTG. The wt M.HinfI and the mutant MTase were purified to near electrophoretic homogeneity by phosphocellulose, DEAE and gel chromatography. Their monomer sizes by SDS/polyacrylamide-gel electrophoresis are 43 kDa and 31 kDa, respectively, in good agreement with that predicted from the nucleotide sequence. DNA methylation experiments with purified enzymes using single-strand and double-strand M13mp18 DNA substrates indicate that while wt enzyme methylates both forms of DNA substrates, the mutant enzyme appears to preferentially methylate ss DNA substrate.

Amino Acid Sequence↗
PubMed1992

Malignant triton tumor of the acoustic nerve. Case report.

The authors present the clinical, radiological, pathological features, and autopsy findings of a patient with malignant triton tumor of the acoustic nerve, which probably arose from a pre-existing acoustic schwannoma. The term "malignant triton tumor" is applied to malignant schwannomas with rhabdomyoblastic differentiation. A cerebellopontine angle tumor with spinal drop metastasis occurred in this patient 10 months after near-total removal of the original tumor.

Female↗
PubMed1991

Bone scintigraphy in acute renal failure with severe loin pain and patchy renal vasoconstriction.

To evaluate the patterns of renal images and the diagnostic value as a screening test of the whole-body bone and renal scintigraphy with technetium-99m-methylene diphosphonate (99mTc-MDP) or -pyrophosphate (99mTc-PYP), we performed bone scintigraphy in 6 patients with acute renal failure (ARF) with severe loin pain and patchy renal vasoconstriction on postcontrast renal computed tomography (CT). All 6 patients were young and previously healthy but experienced severe loin pain after track events. Five took analgesics. Postcontrast renal CT showed patchy low-density areas or diffuse enhancement immediately after radiocontrast injection and then patchy wedge-shaped enhancement 24 or 48 h later, which subsequently disappeared 72 h later. On the whole-body bone scintigrams with 99mTc-MDP or 99mTc-PYP before obtaining renal CT, there was no increased uptake of isotope in the soft tissue, and multiple patchy increased accumulations of the isotope in the kidney were observed in 5 patients. In 2 patients, renal scintigraphies with technetium-99m-dimercaptosuccinate showed photon-deficient areas in the same areas of patchy isotope accumulation in the whole-body bone scintigraphies. Whole-body image and renal scintigraphy with bone-seeking agents may be useful as a screening test and in the search for the theoretical evidence of ARF with severe loin pain and patchy renal vasoconstriction.

Acute Kidney Injury↗
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

Hemorrhagic fever with renal syndrome: MR imaging of the kidney.

Magnetic resonance (MR) imaging of the kidneys was performed in 14 patients with a severe form of hemorrhagic fever with renal syndrome (HFRS), a major public health problem in Far Eastern Asia. To the authors' knowledge, this is the first report of renal assessment with MR imaging in HFRS. Three MR imaging studies were done while patients were in the oliguric phase, 19 were done during the diuretic phase, and three were done during the convalescent phase. The authors differentiated the cortex and the medulla in all 21 T1-weighted examinations and all 25 T2-weighted examinations. Seven T1-weighted examinations (33%) and 20 T2-weighted examinations (80%) showed low signal intensity along the outer portion of the medulla, which thus enabled differentiation from the inner medulla. Low signal intensity along the medulla (especially the outer medulla) on T2-weighted images, possibly representing medullary hemorrhage, is fairly constant and characteristic on MR images of the kidneys in patients with HFRS.

Adult↗
PubMed1989

Scanning electron microscopy of Malassezia furfur in tinea versicolor.

Morphologic features of Malassezia(M.) furfur in the horny layer from clinical lesions of tinea versicolor were examined by scanning electron microscopy and compared with the appearance of fungus in the horny layer from normal skin and in culture. In skin lesions of tinea versicolor, M. furfur showed a variety of growth and reproduction patterns. Although the main patterns were budding yeast forms, various patterns suggesting yeast-mycelial conversion were observed and mycelial hyphae were more prominent in the deeper horny layer than in the superficial layers. However, in the skin of normal persons and in culture, M. furfur existed only as yeast forms and no mycelial hyphae or yeast-mycelial conversion forms were seen. This suggests that the morphologic change of M. furfur, from a yeast form to a mycelial hypha one, may play a role in the induction of the clinical lesion of tinea versicolor.

Biopsy↗
PubMed1989

Comparison of two methods for isolation of Mycobacterium paratuberculosis from bovine fecal samples.

Fecal samples from 131 cattle clinically suspect for paratuberculosis were cultured bacteriologically, using the traditional sedimentation processing method and a processing method that included a centrifugation step. Of 16 samples that were contaminated, 6 were culture-positive on at least 1 medium and by 1 processing method. Ten of 131 (7.6%) fecal samples processed by both methods were lost because of contamination. The number of culture-positive samples (using both processing methods) were 65 of 121 (53.7%) on media without miconazole and 60 of 121 (49.6%) on media with miconazole. Seven of the 121 (5.8%) samples were culture-positive, using centrifugation, after 16 weeks' incubation at 37 C. Thirteen of 60 (21.7%) isolates were obtained only with centrifugation, and 10 of these had low colony counts, suggesting that a centrifugation step may have concentrated microorganisms that would have gone undetected without centrifugation. Six of 60 (10%) isolates positive for M paratuberculosis on the sedimentation method were negative on the centrifugation method. Contamination rates were significantly (P less than 0.001) increased when centrifugation was used. The miconazole significantly (P less than 0.001) decreased contamination rates when centrifugation was used.

Animals↗