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Biomedical subjects

C W Lee

Publications and source records attributed to C W Lee.

At least 163 records · Page 9Linked to original sources
PubMed1998

A case of Farber lipogranulomatosis.

A 35 month old girl had suffered from painful joint contractures of the whole body since a few months after birth, and she gradually developed numerous periarticular and subcutaneous nodules, hoarseness, swallowing difficulty with recurrent respiratory infections, nystagmus, and mental and developmental retardation. She was misdiagnosed as having juvenile rheumatoid arthritis at several university hospitals. Serologic studies for rheumatoid arthritis were all negative. Radiologic findings of the whole body showed osteoporosis and bony erosions; on brain CT the brain was diffusely atrophied. On cine-esophagography barium refluxed into the nasopharynx. Light microscopically, the reticular dermis and subcutis were markedly thickened with hyalinized sclerotic collagen bundles. There were interstitial and perivascular aggregates of foamy histiocytes which were positive for CD-68 immunostaining. On electron microscopy, foamy histiocytes were packed with numerous membrane-bound inclusions having C-shaped or worm-like profiles in addition to many myelin figures, occasional lipid droplets and rare banana-like bodies.

Child, Preschool↗
PubMed1998

Comparison of slotted tube versus coil stent implantation for ostial left anterior descending coronary artery stenosis: initial and late clinical outcomes.

Balloon angioplasty of ostial left anterior descending coronary artery (LAD) lesions has been associated with a high rate of acute complications and late restenosis. Recently, coronary stenting has been proposed as an effective treatment modality for ostial LAD lesions. To evaluate the effects of stent design on the development of late restenosis, we retrospectively analyzed the efficacy of slotted-tube stent implantation (40 patients, Palmaz-Schatz stent) and coil stent implantation (15 patients, tantalum Cordis stent) of ostial LAD stenosis. Six-month angiographic follow-up data were obtained in 31 patients (82%) with slotted-tube stent implantation and 12 patients (86%) with coil stent implantation. Angiographic restenosis was defined as > or =50% diameter stenosis. The angiographic restenosis rate was significantly lower in slotted-tube stent implantation (32%) than in coil stent implantation (67%) (p<0.05). Target lesion revascularization rate of slotted tube stent implantation was significantly lower (26%) than that of coil stent implantation (57%) (p<0.05). Coil stent implantation of ostial left anterior descending artery lesions was associated with higher late restenosis compared with slotted tube stent implantation. In conclusion, slotted-tube stent implantation might be considered to improve late clinical outcomes of ostial LAD lesions.

Angioplasty, Balloon, Coronary↗
PubMed1998

Impaired flow-mediated vasodilation of epicardial coronary artery in vasospastic angina.

To evaluate whether the flow-mediated vasodilation and coronary flow reserve are impaired or not in patients with vasospastic angina (VA), we measured the changes of epicardial coronary artery diameter and flow reserve in spasm related-left anterior descending coronary artery (LAD). The flow mediated-response of epicardial coronary arteries in 15 VA were compared with 15 controls. Using quantitative coronary angiography, we measured the diameter of proximal (pLAD) and middle segment (mid-LAD) of LAD under baseline conditions, during increased blood flow after distal adenosine injection and after proximal administration of nitroglycerin. An increased fraction of average peak velocity after injection of adenosine was similar in both groups [control 340 (mean)+/-24 (SEM)%; VA 330+/-19%]. Flow-mediated vasodilation was preserved in all controls (pLAD 13.1+/-1.4%; mid-LAD 15.8+/-2.5%) but it was significantly impaired in patients with VA (pLAD -1.0+/-1.8%; mid-LAD 0.1+/-3.5%). The vasodilator response to nitroglycerin was comparable in controls (pLAD 25.8+/-2.8%; mid-LAD 27.2+/-2.8%) and VA (pLAD 26.2+/-5.2%; mid-LAD 26.7+/-3.5%). Coronary flow reserve is preserved in patients with VA. However, the flow-mediated response of spasm related-epicardial coronary artery is impaired. This may play an important role in the pathogenesis of coronary artery spasm.

Adult↗
PubMed1997

Late clinical outcomes of cordis tantalum coronary stenting without anticoagulation.

This study was performed to evaluate clinical and angiographic restenosis rates after successful Cordis coronary stent implantation and intravascular ultrasound images were acquired to compare results with quantitative angiographic findings in a subgroup of patients. We conclude that (1) the angiographic restenosis rate of Cordis stent was 19%, which was comparable to that of other slotted-tube stents, and (2) the quantitative coronary angiographic calliper method is reliable for assessing Cordis in-stent restenosis, especially diffuse in-stent restenosis.

Coronary Angiography↗
PubMed1997

Reduction of equilibrative nitrobenzylthioinosine-sensitive nucleoside transporter in tamoxifen-treated MCF-7 cells: an oestrogen-reversible phenomenon.

MCF-7 cells display both nitrobenzylthioinosine (NBMPR)-sensitive (es) and NBMPR-insensitive (ei) equilibrative, but not the Na+-dependent, nucleoside transport. Transport of uridine by es is more sensitive to inhibition by purine nucleosides, whereas the ei component is more sensitive to nucleosides without an amino side group, such as inosine and thymidine. When exposed to 10 microM tamoxifen for 5 days, MCF-7 cells displayed a 44% decrease in the total number of NBMPR-binding sites [Bmax from 245000+/-18000 to 136000+/-25000 sites per cell (mean+/-S.E.M.; n=5; P<0.05)], and a 57% decrease in cell growth with no significant change in binding affinities [Kd from 0.37+/-0.05 to 0.45+/-0.08 nM (n=5; P>0.05)]. Kinetic studies of [3H]uridine transport showed a decrease in the Vmax of the es component from 21.7+/-0.3 (n=8) to 8.4 +/- 2.2 microM/s (n=4; P < 0.05), whereas the Vmax of the ei component [from 4.7 +/- 0.5 (n=8) to 5.8 +/- 1.6 microM/s (n=4; P > 0.05)] and Km values for both components [es from 460 +/- 80 to 630 +/- 280 microM (n>/=4; P > 0.05) and ei from 355 +/- 115 to 440 +/- 220 microM (n>/=4; P > 0.05)] did not change significantly. Oestradiol at 100 nM reversed almost completely the NBMPR-binding site decrease and growth retardation in tamoxifen-treated cells. Thus tamoxifen is shown to cause an oestrogen-reversible decrease of es nucleoside transporters in MCF-7 cells.

Binding Sites↗
PubMed1997

Comparison of six-month results of coronary stenting versus balloon angioplasty alone in patients with acute myocardial infarction.

The purpose of this study was to compare results of delayed elective stent implantation on the infarct-related artery with conventional balloon angioplasty in 97 patients with acute myocardial infarction at 7 to 10 days after symptom onset (stenting in 45 patients, balloon angioplasty in 52 patients). In selected patients, intracoronary stent implantation on the infarct-related artery at 7 to 10 days after symptom onset of acute myocardial infarction is safe, feasible, and may reduce the the frequency of late restenosis compared with balloon angioplasty (the angiographic restenosis rate: 13% in patients with stents vs 52% in patients with balloon angioplasty, p <0.05).

Catheterization↗
PubMed1997

Identification of putative phosphoinositide-specific phospholipase C genes in filamentous fungi.

Five putative phosphoinositide-specific phospholipases C (PLC) genes were identified in three species of filamentous fungi. Using polymerase chain reaction with degenerate oligonucleotide primers, gene fragments encoding amino acid sequences homologous to PLCs of mammals and other organisms were amplified: one sequence from Botryotinia fuckeliana, one from Aspergillus nidulans, and three from Neurospora crassa. The molecular cloning and sequencing of a putative PLC gene (BCPLC1) from B. fuckeliana showed that it encoded a polypeptide containing X and Y domains, the two conserved regions found in all known PLCs. The hypothetical gene product of BCPLC1 was of delta type in its primary structural organization. The identification of three PLC genes in N. crassa shows that multiple PLC isozymes also occur in microbial eukaryotes.

Amino Acid Sequence↗
PubMed1997

Molecular cloning and sequence analysis of a putative ras gene of the phytopathogenic fungus Botryotinia fuckeliana.

We solated and determined the complete nucleotide sequence of a ras gene from Botryotinia fuckeliana, the causal agent of gray mold disease. Furthermore, in two other phytopathogenic fungi, Magnaporthe grisea (rice blast fungus) and Colletotrichum lagenarium (an anthracnose fungus), ras gene homologs were identified by amplifying gene fragments in polymerase chain reactions. The putative ras gene of B. fuckeliana encoded a polypeptide of 212 amino acids, and the coding sequence was interrupted by three short introns. The amino-terminal one third of the predicted Ras protein was highly homologous, and the next one third moderately homologous, to those of mammalian Ras proteins. The carboxy-terminal one third showed no homology, except in the last several amino acids that conformed to the acylation consensus.

Amino Acid Sequence↗
PubMed1997

Isolation and characterization of a benomyl-resistant form of beta-tubulin-encoding gene from the phytopathogenic fungus Botryotinia fuckeliana.

As an initial step to develop a DNA-mediated transformation system using benomyl resistance as a dominant selectable marker in the phytopathogenic fungus Botryotinia fuckeliana (anamorph, Botrytis cinerea), we have constructed a phage lambda genomic DNA library of a benomyl-resistant strain 91T-1, and a beta-tubulin-encoding gene benA was isolated, cloned and sequenced. Southern blot analysis suggested that a single copy of benA is present in the genome of B. fuckeliana. The benA gene is composed of seven exons which are separated by six introns of 52 to 135 bp. The intron consensus sequences are similar to those of other fungal genes. The deduced amino acid sequence (447 amino acid residues) is highly homologous to those of other fungal beta-tubulin-encoding genes. Comparison of the sequences around codons 198 and 200 in benomyl-resistant and sensitive strains revealed that the benAHR allele from the benomyl-resistant strain 91T-1 contained a mutation at codon 198 from GAG (Glu) to GCG (Ala), which has been correlated with high resistance to benzimidazole fungicides including benomyl in various filamentous fungi.

Alleles↗
PubMed1997

Bidirectional pigment granule migration in isolated retinal pigment epithelial cells requires actin but not microtubules.

In the teleost retinal pigment epithelium (RPE), melanin pigment granules disperse into long apical projections in the light and reaggregate into the cell body in the dark. To investigate the cytoskeletal mechanisms responsible for these movements, we have examined the effects of cytoskeletal inhibitors on pigment granule transport in cultured, dissociated RPE cells using time-lapse video microscopy. The kinetics of pigment granule transport during normal aggregation and dispersion are quite distinct: during aggregation, all pigment granules undergo simultaneous, nonsaltatory centripetal movement (mean velocity 3.6 microm/min); during dispersion, individual granules undergo independent, bidirectional saltatations (mean velocities 3.7 microm/min centrifugal; 1.1 microm/min centripetal). Nocodazole disruption of microtubules within the RPE apical projections had little effect on the kinetics of pigment granule movement, and essentially no effect on extent of pigment granule aggregation or dispersion, or on maintenance of the fully aggregated or fully dispersed states. In contrast, cytochalasin D (CD) treatment blocked net aggregation and dispersion of pigment granules, and compromised maintenance of the fully aggregated and dispersed states. These observations suggest that the actin cytoskeleton plays an important role in both centripetal and centrifugal transport of pigment granules in teleost RPE cells.

Actins↗
PubMed1997

Ether lipid composition and molecular species alterations in carp brain (Cyprinus carpio L.) during normoxic temperature acclimation.

Carp (Cyprinus carpio L.) whole brain was used to investigate the thermal acclimation changes under normoxic conditions of three-subclasses (alkenylacyl-, alkylacyl- and diacyl-subclasses) of choline glycerophospholipids (CGP), ethanolamine glycerophospholipids (EGP) and inositol glycerophospholipids (IGP) as well as their acyl chain profiles and molecular species composition. The alkenylacyl subclass of CGP and IGP and the alkylacyl subclass of CGP and EGP varied significantly during summer (25 degrees C) acclimation compared to winter (5 degrees C). The levels of alkenylacyl and alkylacyl-CGP, alkylacyl-EGP and alkenylacyl-IGP were 17.3-, 3.7-, 3.5- and 1.3-fold higher in the summer, respectively, while the alkenylacyl EGP was moderately lower. The levels of diacyl subclasses from CGP and IGP were considerably lower in the summer to compensate for the higher proportion of alkenylacyl and alkylacyl subclasses. Significant changes of ether phospholipids and the reorganization of the molecular species composition of all lipid subclasses may be associated with the "fine tuning" of the physical properties of the cellular membranes in carp brain due to temperature acclimation. The overall acyl chain profile of the three subclasses of carp brain phospholipids showed differences in composition depending upon the subclass of the individual phospholipid. Generally the polyunsaturated fatty acid (PUFA) chain composition increased relative to monounsaturated fatty acid (MUFA) and saturated fatty acids (SFA) during winter acclimation. Docosahexaenoic acid (DHA) was richer in the winter compared to summer. However, no DHA was found in ether-containing species of IGP from either winter or summer, except for 2% in alkylacyl-IGP during the summer. The above observations suggest that the content of ether phospholipids (alkenylacyl and alkylacyl) as well as the reorganization of the molecular species composition of all phospholipids may serve to maintain a functional fluid-crystalline state to preserve the signaling functions in carp brain.

Acclimatization↗
PubMed1997

Dietary alpha-linolenic acid increases the biosynthesis of the choline glycerophospholipids from [14C]CDPcholine in rat liver and kidney but not in brain.

The effect of feeding rats for 30 days with diets containing high levels of linoleic acid (sunflower oil, SO) or alpha-linolenic acid (perilla oil, PO) was studied in the liver, kidney and brain. The PO group showed a higher labeling of choline glycerophospholipids (CGP) in liver and kidney but no difference with the SO group in ethanolamine glycerophospholipids (EGP) labeling. The brain displayed the lowest incorporation of both precursors and no difference between the two diets. Analyses of brain CGP and EGP fatty acid composition showed that in the PO group the ratio n-6/n-3 was lower than in the SO group, mainly as a consequence of lower levels of n-6 fatty acids. The mole % of docosahexaenoate (DHA) in these lipids was the same for both groups and only triacylglycerols (TAG) displayed a higher DHA. Therefore, at least in the brain, the magnitude of fatty acid changes observed in CGP and EGP for the PO group does not affect the uptake/incorporation of the precursors into phospholipids.

Animals↗
PubMed1997

Improvements are needed in the existing packaging of medicated oils containing methyl salicylate.

In view of the toxic potential of medicated oils containing methyl salicylate, we have studied the existing packaging of 10 commonly used preparations from Hong Kong and Singapore and identified areas for improvement with respect to the prevention of poisonings. They were all packed in translucent bottles without child-resistant closures. The methyl salicylate content ranged from 15 to 67%. Many preparations also contained other potentially toxic ingredients in significant amounts, such as turpentine oil and camphor. The contents of the larger bottles could generally be emptied more easily because of the greater size of their openings. The product with the highest methyl salicylate content also had the biggest opening of all. The threat from ingestion of medicated oils containing methyl salicylate can probably be 'reduced' by: (i) using child-restraint closures; (ii) restricting the size of both the openings and the bottles; and (iii) reducing the methyl salicylate content.

Camphor↗
PubMed1997

Central inhibition of nitric oxide synthase modulates upper gastrointestinal motor activity.

We investigated the role of central nitric oxide (NO) synthase inhibition in the modulation of fasting gastrointestinal motor activity and gastric emptying rate of solid nutrient meals in conscious dogs. N(omega)-nitro-L-arginine methyl ester and N(omega)-nitro-L-arginine were infused intracerebroventricularly. Circular muscle contractions were recorded with surgically implanted strain gauge transducers. Gastric emptying was measured by a radiolabeled meal. The inhibition of NO synthase in the brain suppressed phase III activity in the stomach and the duodenum but not in the jejunum or the ileum. However, the central inhibition of NO synthase had no significant effect on the rate of gastric emptying of solid nutrient meals or the duration of postprandial disruption of migrating motor complex cycling. The central actions of NO synthase inhibition were blocked by bilateral truncal vagotomy but not by intravenous administration of propranolol or phentolamine. We conclude that the inhibition of NO synthase in the brain generates a stimulus that selectively inhibits gastric and duodenal phase III activities. This stimulus, however, may not affect the postprandial gastroduodenal motor activity or the rate of gastric emptying of solid nutrient meals.

Animals↗
PubMed1997

Ca2+ channel blockade by verapamil inhibits GMCs and diarrhea during small intestinal inflammation.

The aim of this study was to investigate whether the blockade of L-type Ca2+ channels with verapamil suppresses giant migrating contractions (GMCs) and therefore diarrhea during small intestinal inflammation. Small intestinal inflammation was induced by infection with the nematode Trichinella spiralis. T. spiralis infection alone significantly increased the frequency of GMCs and decreased the frequency of phase III activity in the small intestine for 9 days. The increased frequency of GMCs was associated with diarrhea. Immunohistochemical staining with specific antibodies indicated that the number of neutrophils and mast cells increased significantly in the jejunal lamina propria during T. spiralis infection. Only the neutrophils increased significantly in the muscularis externa of the jejunum. Myeloperoxidase (MPO) activity increased significantly in the jejunal and ileal lamina propria. Daily verapamil administration during T. spiralis infection significantly reduced the frequency of GMCs and diarrhea but had no further significant effect on the already reduced frequency of phase III activity. Verapamil administration, however, did not reduce MPO activity or immunocyte infiltration in the jejunum or ileum. We conclude that blockade of L-type Ca2+ channels selectively reduces the frequency of GMCs and therefore diarrhea during small intestinal inflammation. The decreased frequency of GMCs is not secondary to a reduction in the inflammatory response.

Animals↗
PubMed1997

Adrenal carcinosarcoma--a case report.

Carcinosarcoma of the adrenal gland is an extremely rare variant of adrenocortical carcinoma, characterized by a biphasic pattern of carcinoma and sarcoma-like components. We report a case of adrenal carcinosarcoma occurring in a 61-year-old Korean man who presented with right flank pain of one month duration radiating to the back and right iliac crest. The tumor measured 12 x 12 x 7 cm and adhered to the liver and right upper pole of the kidney. The carcinomatous component of the tumor showed polygonal cells in a broad anastomosing trabecular pattern with delicate slit-like vascular channels; the sarcomatous component showed uniform spindled cells in a fascicular pattern. Both the carcinomatous and sarcomatous portions of the tumor were positive for pan-cytokeratin, and vimentin stained only the sarcomatous areas.

Adrenal Gland Neoplasms↗
PubMed1996

Tamoxifen inhibits nitrobenzylthioinosine-sensitive equilibrative uridine transport in human MCF-7 breast cancer cells.

Tamoxifen inhibits the binding of [3H]nitrobenzylthioinosine ([3H]NBMPR) to human MCF-7 breast cancer cells with an IC50 of 8 microM. Tamoxifen at 30 microM changed the apparent Kd for [3H]NBMPR binding from 0.63 +/- 0.12 to 4.75 +/- 0.58 nM, with little effect on the Bmax (311000 +/- 76000 and 263000 +/- 46000 sites per cell for untreated and tamoxifen-treated cells respectively). Corresponding to this decrease in binding of [3H]NBMPR in the presence of tamoxifen was an inhibition of NBMPR-sensitive equilibrative transport of 50 microM [3H]uridine (IC50 7-10 microM). In the presence of 15 microM tamoxifen, the apparent K(m) for [3H]uridine transport was increased from 390 +/- 30 to 1500 +/- 250 microM, with no change in Vmax (12.0 +/- 0.1 and 11.3 +/- 4.3 microM/s for untreated and tamoxifen-treated cells respectively). The inhibitory effect of tamoxifen on NBMPR-sensitive equilibrative uridine transport was specific, as similar results were also observed in HL-60 leukaemia and EL4 lymphoma cells. Furthermore a similar concentration of tamoxifen had no effect on the NBMPR-insensitive equilibrative transport of uridine in MCF-7, HL-60 and Morris 7777 hepatoma cells, and on the Na(+)-dependent transport of uridine in murine splenocytes. In this paper we demonstrate that tamoxifen by itself might have some antiproliferative effects through inhibition of DNA synthesis by blocking the nucleoside salvage pathway.

Animals↗