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K S Ko

Publications and source records attributed to K S Ko.

30 records · Page 2Linked to original sources
PubMed1999

Phylogenetic re-evaluation of Trametes consors based on mitochondrial small subunit ribosomal DNA sequences.

Mitochondrial small subunit ribosomal DNAs of Cerrena unicolor and Trametes consors were sequenced and compared with those of known mushroom taxa. Trametes consors is a species recently transferred from Irpex, and Cerrena is a genus closely related to Trametes. The present phylogenetic tree showed that Cerrena unicolor and Trametes consors clustered together and made an independent lineage from the Trametes group. A new combination, Cerrena consors (Berk.) Ko and Jung, comb nov., is proposed here by transferring Trametes consors into Cerrena based on molecular data along with taxonomic evidence.

Basidiomycota↗
PubMed1999

Molecular phylogeny of Trametes and related genera.

Mitochondrial small subunit ribosomal DNAs were sequenced and phylogenetically analyzed for Trametes and related genera of Ryvarden's Trametes group. Parsimony and distance analyses indicated that most of trimitic genera with white rotting habit of the Trametes group clustered within a single clade, suggesting that they may have originated from a common ancestor. The phylogenetic position and generic placement of Trametes consors was uncertain as yet. Trametes trogii grouped with Coriolopsis gallica and indicated that color of the basidiocarp is a poor character at generic level. Nucleotide differences between Daedaleopsis confragosa and D. tricolor were quite few and both species closely grouped together in a same clade, thus supporting that D. tricolor might be an ecotype of D. confragosa.

DNA, Fungal↗
PubMed1999

Bilateral dentigerous cysts--report of an unusual case and review of the literature.

Dentigerous cysts are the most common developmental cysts of the jaws, most frequently associated with impacted mandibular third molar teeth. Bilateral dentigerous cysts are rare and occur typically in association with a developmental syndrome. The reported occurrence of bilateral dentigerous cysts in the absence of a syndrome is rare and, to date, only 11 cases have been described. Here, we report a case of bilateral nonsyndromic, dentigerous cysts and review the literature for this unusual finding.

Adult↗
PubMed1998

Treponema denticola outer membrane inhibits calcium flux in gingival fibroblasts.

Treponema denticola is a cultivable oral spirochete which perturbs the cytoskeleton in cultured cells of oral origin, but intracellular signalling pathways by which it affects actin assembly are largely unknown. As the outer membrane (OM) of Treponema denticola disrupts actin-dependent processes that normally require precise control of intracellular calcium, we studied the effects of an OM extract on internal calcium release, ligand-gated and calcium release-activated calcium channels, and related mechanosensitive cation fluxes in human gingival fibroblasts (HGF). Single-cell ratio fluorimetry demonstrated that in resting cells loaded with Fura-2, baseline intracellular Ca2+ concentration ([Ca2+]i) was not affected by treatment with OM extract, but normal spontaneous [Ca2+]i oscillations were dramatically increased in frequency for 20 to 30 min followed by complete blockade. OM extract inhibited ATP-induced and thapsigargin-induced release of calcium from intracellular stores by 40 and 30%, respectively. Addition of Ca2+ to the extracellular pool following depletion of intracellular Ca2+ by thapsigargin and extracellular Ca2+ by EGTA yielded 59% less replenishment of [Ca2+]i in OM extract-treated than in control HGF. In cells loaded with collagen-coated ferric oxide beads to stimulate integrin-dependent calcium release, baseline [Ca2+]i was nearly doubled but was not significantly different in control and OM extract-treated cells. Magnetically generated tensile forces on the beads induced >300% increases of [Ca2+]i above baseline. Cells preincubated with OM extract exhibited dose-dependent and time-dependent reductions in stretch-induced [Ca2+]i transients, which were due to neither loss of beads from the cells nor cell death. The T. denticola OM inhibitory activity was eliminated by heating the OM extract to 60 degrees C and by boiling but not by phenylmethylsulfonyl fluoride treatment. Thus nonlipopolysaccharide, nonchymotrypsin, heat-sensitive protein(s) in T. denticola OM can evidently inhibit both release of calcium from internal stores and uptake of calcium through the plasma membrane, possibly by interference with calcium release-activated channels.

Calcium↗
PubMed1997

Reversible cystic disease associated with pulmonary tuberculosis: radiologic findings.

PURPOSE: The authors describe radiologic findings of cystic lung disease associated with pulmonary tuberculosis. MATERIALS AND METHODS: Three immunocompetent women with pulmonary tuberculosis were seen with acute respiratory failure and diffuse bilateral pulmonary opacity depicted at admission chest radiography. The women did not have acquired immunodeficiency syndrome, or AIDS. They were aged 26, 27, and 52 years. RESULTS: Follow-up radiography and computed tomography showed multiple air-filled cystic lesions in both lungs, which disappeared almost completely after antituberculous chemotherapy (isoniazid, rifampin, ethambutol hydrochloride, and pyrazinamide). CONCLUSION: Pulmonary tuberculosis manifested with reversible multiple cystic lung disease in three immunocompetent patients.

Adult↗
PubMed1995

Clinical heterogeneity of insulin dependent diabetes mellitus in Korea.

This study was undertaken to find out how many current Korean patients with insulin dependent diabetes mellitus (IDDM) had a previous history of non-insulin requiring phase. Fasting serum C-peptide levels were measured in the 2300 diabetic patients during the visit to the Asan Medical Center, Seoul, Korea. Fifty-nine patients showed fasting serum C-peptide levels below 0.13 nmol/l. These 59 patients were classified further into two groups according to their history of insulin requirement: group A who required insulin within 1 year after diagnosis or presented initially as diabetic ketoacidosis and group B who had non-insulin requiring phase at least for 1 year (median: 5 years; range: 1-23 years). Twenty-six patients (44%) were classified into group A and 27 patients (46%) into group B. Median age of onset was 26 years (range: 10-50 years) and 45 years (range: 23-73 years) in groups A and B, respectively (P < 0.001). While the two groups had similar values in the current and maximum body mass indices, sex ratio and the prevalence of islet cell antibodies, 58% of the group A and 7% of the group B patients had histories of diabetic ketoacidosis. These results suggest a clinical heterogeneity in patients with IDDM in Korea.

Adolescent↗
PubMed1995

B-lymphocyte-stimulating polysaccharide from mushroom Phellinus linteus.

Hot water extract prepared from the mycelial culture of mushroom Phellinus linteus stimulated polyclonal antibody production in an in vitro culture system. The active fraction PLP was purified from the extract ca. 1030-fold by ethanol precipitation followed by DEAE-cellulose and gel permeation chromatography. PLP contained 13.2% (w/w) peptide and 82.5% (w/w) carbohydrate. About 6.8% (w/w) of the total carbohydrate was uronic acid. The molecular weight distribution of PLP was found to be nearly homogeneous (153 kDa) in gel permeation HPLC analysis. Neutral sugar composition analysis revealed Ara (7.5%), Xyl (3.7%), Glc (21.1%), Gal (24.1%) and Man (44.2%). Uronic acid was identified as a glucuronic acid by gas chromatography. Ten amino acids were detected and Asp and Glu were the major components. In our assay system, the half-maximal concentration of PLP for B-lymphocyte stimulation was ca. 3 micrograms/ml. Partial acid hydrolysis as well as sodium periodate treatment of PLP decreased the activity significantly, suggesting that both the full molecular size and the sugar moiety were essential. However, proteinase K treatment for up to 48 h did not affect the activity.

Acetylation↗
PubMed1993

Direct relationship between elevated free testosterone and insulin resistance in hyperprolactinemic women.

Women with hyperprolactinemia have been reported to have hyperandrogenemia and/or insulin resistance. However, little is known about the association of hyperandrogenemia and insulin resistance in these women. To investigate whether hyperandrogenemia and/or insulin resistance occur in hyperprolactinemic women, and to assess the relationship between them, we measured basal androgen level and both glucose and insulin levels after oral glucose administration in 20 hyperprolactinemic women and 7 female control subjects. Free testosterone level was higher and estradiol level lower in hyperprolactinemic women than in control subjects (p < 0.05), whereas dehydroepiandrosterone sulfate (DHEAS) and total testosterone levels were similar (p > 0.05). Both fasting glucose and insulin levels didn't differ in the two groups (p > 0.05). However, both serum glucose and insulin levels, after a 75 g glucose load, were significantly increased in hyperprolactinemic women, (p = 0.001, p < 0.001, respectively). In simple linear regression analysis in hyperprolactinemic women, only free testosterone level had a positive correlation with the incremental area under the insulin curve (insulin-IAU) (r = 0.47, p < 0.05). In multiple stepwise regression analysis, free testosterone level, mean blood pressure and DHEAS level were associated significantly with insulin-IAU (beta = 0.98, p < 0.0001; beta = 0.58, p = 0.002; beta = -0.67, p < 0.003, respectively). These results suggest that insulin resistance is closely related to elevated free testosterone level in hyperprolactinemic women.

Adult↗