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Biomedical subjects

S Y Lim

Publications and source records attributed to S Y Lim.

At least 19 recordsLinked to original sources
PubMed2006

Activation of mouse protease-activated receptor-2 induces lymphocyte adhesion and generation of reactive oxygen species.

BACKGROUND AND PURPOSE: Protease-activated receptor-2 (PAR-2) is expressed on lymphocytes and endothelial cells, and plays a significant role in inflammatory reactions. Since leukocyte-endothelial cell interaction and reactive oxygen species (ROS) generation are hallmarks of the development of inflammation, the effects of PAR-2 activation by trypsin on lymphocyte adhesion and ROS generation was examined utilising PAR-2 wild type and knockout (PAR-2-/-) mice. EXPERIMENTAL APPROACH: Lymphocyte adhesion to the luminal surface of mouse isolated aortae was measured using 51Cr-labelled leukocytes and ROS generation from isolated lymphocytes was quantified using chemiluminescence. KEY RESULTS: Trypsin induced adhesion of lymphocytes when added exogenously to the endothelial surface of the aorta for 30 min. Similarly, increased lymphocyte adhesion was also observed when mice were injected with trypsin intravenously 24 h prior to the adhesion assay, an effect which was partly ICAM-1 mediated. Trypsin also increased ROS generation from isolated mouse lymphocytes in a dose-dependent manner. The increase in lymphocyte adhesion and ROS production in response to trypsin were abolished in PAR-2-/- mice indicating a PAR-2 dependent mechanism. Superoxide dismutase had a greater inhibitory effect in PAR-2-/- mice compared to wild type mice when lymphocytes were stimulated with PMA but not trypsin. CONCLUSIONS AND IMPLICATIONS: The present study indicates that activation of PAR-2 may be an important factor in modulating lymphocyte adhesion and ROS generation. The results have implications for developing anti-inflammatory strategies.

Animals↗
PubMed2006

Development of mesophase pitch derived mesoporous carbons through a commercially nanosized template.

Mesoporous carbons (MCs) with a high surface area (up to 900 m2/g), large pore volume (up to 2.1 cm3/g), high mesopore ratio (94%), and high yield (70%) were successfully prepared from an AR mesophase pitch, using a commercially nanosized silica template. The removal of the template provided some larger mesopores of 25-50 nm (pore I) with a surface area of ca. 300 m2/g, while the successive carbonization opened the closed pores within the carbon body to give smaller mesopores of 2-10 nm (pore II) with a similar surface area. During the carbonization of pitch precursor, the evaporation of volatile components swells the carbon to introduce the second mesopores among the domains and even microdomain units because of their rearrangements and overlappings in the process. The addition of iron salt with the silica template resulted in a remarkable increase of the surface area (ca. 300 m2/g) by introducing mesopores of 3-5 nm. The resultant MCs maintained some graphitizable natures derived from the anisotropic precursor. Their graphitization at 2400 degrees C provided the graphitic structure with large surface areas (270-460 m2/g) and mesoporosity.

Journal Article↗
PubMed2006

The elevation of the constructed auricle with a temporoparietal fascial flap wrapping a resorbable plate.

During the second stage reconstruction of the auricle in patients with microtia, we modified Nagata's method and two technical improvements were possible. After the implanted auricle was separated from the bed, we harvested the temporoparietal fascial flap through helical rim incision instead of incising the temporal scalp. So the surgical scar over the temporal region was avoided. Thereafter, a costal cartilage wedge was carved and grafted to the posterior aspect of the conchal region to get a firm projection. But in cases of unavailable costal cartilage wedge graft, we used a resorbable plate composed of polylactic and polyglycolic acid as a substitute for the former so that we could create firm elevation and sufficient ear projection. Between June 2002 and May 2004, 28 patients underwent this operation with the temporoparietal fascial flap and resorbable plating system. There was no complication resulting from our technique. It was possible to create firm elevation and good frontal projection even if there was no available cartilage wedge. Additionally, by harvesting the temporoparietal fascia through helical rim incision, we avoid creating additional scars on the scalp.

Biocompatible Materials↗
PubMed2006

Clinics in diagnostic imaging (110). Right-sided tubal ligation clips complicated by the formation of an infected retention cyst.

A 35-year-old Chinese woman presented with a five-day history of right iliac fossa pain and mass. She had no significant past medical history apart from laparoscopic tubal ligation performed years ago. Pelvic ultrasonography demonstrated a well-rounded cystic mass with homogeneous internal echoes and a brightly echogenic component, compatible with tubal ligation clips. Right adnexal infected retention cyst secondary to tubal ligation clips was diagnosed. Complications of female sterilisation are rare but nevertheless have been reported and accounted for symptoms of lower abdominal pain, and should be considered as a differential diagnosis.

Adult↗
PubMed2001

Transfusion-induced malaria in a child after open heart surgery in Korea.

We had an opportunity to evaluate a child who developed fever approximately two to three weeks after the open heart surgery for tetralogy of Fallot. His peripheral blood smear showed rings and various stages of Plasmodium vivax. The patient had received packed red blood cells during the surgery and postoperative care, one unit of which was later proved sero-positive for malaria. The possibility of malaria should be included in the differential diagnosis of the patients with unexplained fever after multiple blood product transfusions for the open heart surgery.

Animals↗
PubMed2001

Anti-lymphoma immunity: relative efficacy of peptide and recombinant DNA vaccine.

The efficacy of vaccines consisting of (1) Ig idiopeptides of a murine B-lymphoblastoma, 2C3, and (2) a corresponding scFV-expressing DNA construct was determined on the basis of their ability to induce anti-tumor immune response and protection against tumor growth. Peptide-KLH complexes and a plasmid expressing single-chain variable fragment (scFv) corresponding to 2C3 Ig VH and VL chains were used separately as vaccines. Immunized BALB/c mice were bled and then challenged with live 2C3 tumor. Survival of various challenged groups was also determined. The results indicate that CDR3-H (VH3) peptides, and the plasmid DNA when given with GM-CSF, only moderately retarded tumor growth, whereas killed 2C3 tumor vaccine induced lasting protection, as shown earlier. Both peptides and scFv-plasmid induced circulating anti-Id antibodies, but no specific cytotoxic T-cell (CTL) activity was detected. However, in spite of their inability to induce CTL activity, both idiopeptides and the scFv-expressing plasmid DNA displayed epitopes recognized by an Id-specific long-term splenic CTL line (A102) obtained from mice vaccinated with killed 2C3 tumor.

Animals↗
PubMed2000

Effect of dietary docosahexaenoic acid and phosphatidylcholine on maze behavior and fatty acid composition of plasma and brain lipids in mice.

We investigated the effects of dietary docosahexaenoic acid (DHA, 22:6 n-3) and phosphatidylcholine (PC) on maze behavior and brain fatty acids in mice. Male Crj:CD-1 mice (3 wk old) were fed a diet containing 2% DHA and 3% palm oil (DHA group); 5% PC (PC group); 1% DHA, 2.5% PC and 1.5% palm oil (DHA + PC group); 5% palm oil (Palm oil control group) or MF laboratory chow (MF control group) for 7 mo. After this time maze-learning ability was assessed. The time required to reach the maze exit and the number of times that a mouse strayed into blind alleys in the maze were measured three times every four days. After the last learning test, all mice were sacrificed and plasma and brain were analyzed for fatty acid composition. The DHA and PC groups required less time to reach the maze exit and strayed less into blind alleys than the control group in the third trial. The difference between the DHA or PC groups and control mice was statistically significant (p < 0.05). In the total lipids of plasma and brain of mice fed DHA, there was a significant increase in DHA levels and a concomitant decrease in arachidonic acid (AA, 20:4 n-6). Similar changes in fatty acid composition were observed in brain phosphatidylcholine and phosphatidylethanolamine for this group of mice. However, this pattern of changes in brain fatty acids was not evident in the PC group. Our data suggest that maze-learning ability in mice is enhanced by intakes of DHA and PC. However, the mechanisms by which the DHA and PC diets improved learning ability appear to be different. A synergistic effect of DHA and PC on learning ability is not apparent in the DHA + PC group.

Animals↗
PubMed2000

Intakes of dietary docosahexaenoic acid ethyl ester and egg phosphatidylcholine improve maze-learning ability in young and old mice.

The effect of dietary docosahexaenoic acid (DHA) [22:6 (n-3)] ethyl ester (EE) and egg-phosphatidylcholine (PC) on maze-learning ability in young and old mice was studied. Male Crj:CD-1 mice aged either 3 wk or 14 mo were fed a diet containing 2 g DHA-EE/100 g diet plus 3 g palm oil/100 g diet (DHA-EE Group), 5 g egg-PC/100 g diet (egg-PC Group), 1 g DHA-EE/100 g diet plus 2.5 g egg-PC/100 g diet plus 1.5 g palm oil/100 g diet (DHA-EE + egg-PC Group) or 5 g palm oil/100 g diet (Control Group) for 5 mo. Maze-learning ability was assessed 4 mo after the start of the experiment. The time required to reach the maze exit and the number of times that a mouse strayed into blind alleys in the maze were measured in three trials every 4 d. In trial 2 of young mice, performed on d 4 after the first trial, the DHA-EE group required less (P < 0.05) time to reach the maze exit and DHA-EE and egg-PC groups strayed (P < 0.05) into blind alleys fewer times than the control group. In trial 2 of old mice, the DHA-EE, egg-PC and DHA-EE + egg-PC groups needed less (P < 0.05) time to find the exit and spent a fewer (P < 0.05) number of times in blind alleys than did the control group. The DHA-EE, DHA-EE + egg-PC and egg-PC groups strayed into blind alleys fewer times than the control group in trial 3 of old mice (P < 0.05). Our results suggest that the intake of DHA-EE and the egg-PC diet effectively enhances maze-learning ability and brain functions in old mice.

Aging↗
PubMed2000

Incidence and characterization of Listeria monocytogenes from domestic and imported foods in Korea.

A total of 1,537 domestic and imported food products were examined for the incidence of Listeria monocytogenes between 1993 and 1997 in Korea. L. monocytogenes was detected using the U.S. Department of Agriculture isolation method. Isolated L. monocytogenes was confirmed by polymerase chain reaction with hly1 and hly2 primers designed from the listeriolysin O. Overall, 122 samples (7.9%) contained L. monocytogenes. The rate of isolation was 4.3% for beef, 19.1% for pork, 30.2% for chicken, 1.2% for shellfish, 4.4% for raw milk, 4.4% for frozen smoked mussels, and 6.1% for ice cream. No L. monocytogenes was found in pasteurized milk, pasteurized processed cheese, saltwater fish, dried seafoods, or ham. The overall incidence was lower than that reported in previous studies from other countries. Most isolates were serotype 1/2b except for chicken, in which serotype 1/2a was predominant. The serotyping results might imply the presence of food or geography-specific L. monocytogenes strains.

Animals↗
PubMed1999

Analyses of glycolipids from fish, shellfish, and sea snake lipids by high-performance liquid chromatography.

To determine the existence of glycolipids (neutral glycosphingolipid and glycoglycerolipid) in sea snake, round frigate mackerel, sardine, sea urchin, and abalone, we performed silica gel chromatography and high-performance liquid chromatography (HPLC) using an Aquasil-SS column and a C(8)-reversed phase silica gel column. HPLC with a UV absorption detector was used to analyze neutral glycosphingolipid. These chromatograms showed typical peaks in round frigate mackerel lipid, in sea snake crude fat, in abalone intestine lipid, and in sea urchin intestine lipid. UV-HPLC was also used to analyze glycoglycerolipid. These chromatograms indicated a large peak in round frigate mackerel lipid and a small peak in purified sardine oil. In addition, we observed the same peaks in the glycolipid fraction of round frigate mackerel muscle lipids and sea snake crude fat using a differential refractometer detector. The results of this study suggest that the peaks are neutral glycosphingolipid or glycoglycerolipid and that neutral glycosphingolipid and glycoglycerolipid may have specific physiological functions in each living creature.

Animals↗
PubMed1997

Performance of ULV formulations (Pesguard 102/Vectobac 12AS) against three mosquito species.

Adulticidal and larvicidal performances of a water-based pyrethroid microemulsion Pesguard PS 102 (AI d-allethrin and d-phenothrin, both at 5.0% w/w) and Vectobac 12AS, an aqua-suspension Bacillus thuringiensis israelensis (B.t.i.) formulation (AI 1,200 ITU/mg) were assessed against mosquitoes Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus using a Leco ULV Fog Generator Model 1600 and a Scorpion 20 ULV AirBlast Sprayer. Laboratory-cultured mosquito adults and larvae were used for efficacy assessment. For trials using Leco, both pyrethroid and bacterial formulations were dispersed both singly and in combination with Pesguard PS 102 at a dosage of 0.2 liters/ha and B.t.i. at a dosage of 1.0 liter/ha. Similar trials with the Scorpion were also conducted with Pesguard PS 102 at a dosage of 0.2 liters/ha and a higher dosage of B.t.i. (1.5 liters/ha). Experiments were conducted in a football field (200 x 100 m) where five check points at 10, 25, 50, 75, and 100 m downwind from the spray nozzle were chosen for efficacy assessments. Knockdown and mortality were scored at 1 and 24 h postspraying. Results from both trials showed that mortality values varied with distance from spray nozzle. For trials with Leco, fogging with the combination of Pesguard PS 102 and B.t.i. provided larvicidal mortality of > 80% for both Aedes species and of > 60% for Cx. quinquefasciatus larvae at several check points, depending on wind conditions. Complete mortality of adult Aedes mosquitoes at 24 h posttreatment was also achieved, while mortality values for Culex adults reached > 90% under strong wind conditions. As for trials with the Scorpion 20, high adult and larval mortalities were also achieved, with > 90% mortality at some check points. The above study demonstrated the possibility of achieving both larvicidal and adulticidal effects when using a combination of B.t.i. and Pesguard PS 102 in ULV space spray.

Aedes↗
PubMed1993

The RRE of human immunodeficiency virus type 1 contributes to cell-type-specific viral tropism.

As part of a general program investigating the mechanism of the Rev axis of human immunodeficiency virus type 1 (HIV-1) autoregulation, a series of proviral HIV-1 mutants which differ from the parental HXB2 strain at selected positions within the RRE were constructed. All of the mutations were designed to perturb the RRE by introducing local helix disruptions without altering the coding potential of the overlapping envelope open reading frame. Viral replication in various cell types was monitored by a cell supernatant reverse transcriptase assay and Northern (RNA blot) analysis. All proviral RRE mutants displayed at least some impairment in replication. However, the relative impairment varied drastically among the various cell types tested. This suggests that the RRE may contribute to cell-type-specific viral tropism.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Employee stress and health complaints in jobs with and without electronic performance monitoring.

Current applications of electronic performance monitoring based on job design theories that consider worker performance rather than stress issues are likely to generate unsatisfying and stressful jobs (Smith et al, 1986). This study examines critical job design elements that could influence worker stress responses in an electronic monitoring context. A questionnaire survey of employees in telecommunications companies representative of each region in the United States examined job stress in directory assistance, service representative and clerical jobs with specific emphasis on the influence of electronic monitoring of job performance, satisfaction and employee health. Useable surveys were received from 745 employees representing seven operating companies and AT & T; a response rate of about 25%. The results of this survey indicated that employees who had their performance electronically monitored perceived their working conditions as more stressful, and reported higher levels of job boredom, psychological tension, anxiety, depression, anger, health complaints and fatigue. It is postulated that these effects may be related to changes in job design due to electronic performance monitoring.

Journal Article↗
PubMed1992

Legionella species isolated from cooling towers in Kuala Lumpur.

Three building complexes in Kuala Lumpur were surveyed for the presence of legionellae in cooling towers. The organisms were grown from 12 out of 46 samples of water collected from 30 towers. L. pneumophila serogroups 1 and 7 were the commonest serogroups isolated. None belonged to the Pontiac subgroup of L. pneumophila serogroup 1.

Legionella↗
PubMed1990

Aplasia cutis congenita. A case report and annotation.

Aplasia cutis congenita (ACC) including epidermolysis bullosa (EB) are rare congenital conditions. In ACC there is a localised absence of skin while in EB blistering occurs with a split at the epidermal or dermal level. In the past these 2 conditions have been reported to occur in the same patient. A case of a Gurkha baby girl illustrating just such an entity with severe erosive defects over the head, face, trunk and acral parts of the limbs presenting at birth is reported. There was also widespread blistering over the chest, abdomen and back. The baby died after 3 days from serious complications.

Epidermolysis Bullosa, Junctional↗
PubMed1990

Charge association. A case report and short annotation.

A premature female infant was noted to have an unusual combination of abnormalities, consistent with the CHARGE ASSOCIATION. 1. Left (L) choanal stenosis 2. Fallot's Tetralogy 3. Esophageal atresia with distal TOF (Tracheo-Oesophageal Fistula) 4. Duodenal stenosis 5. Annular pancreas with ectopic pancreatic tissue in the proximal jejunum. Baby had surgery for the gastrointestinal tract abnormalities. She lived for only 19 days.

Abnormalities, Multiple↗
PubMed1990

Computer applications in orthopaedics.

With the rapid developments in microprocessors, the widespread availability of computers has brought about broad applications in the field of orthopaedics. The present technology enables large quantities of data to be logically processed in a very short span of time. This has led to the development of information management database systems where relevant medical information may be retrieved very quickly and effectively. The analytical power of the computer has also been utilised in expert systems to assist in clinical-decision making process. Computer graphics have revolutionised the visualisation of physical features of internal and external body parts, providing new and improved modalities of diagnosis. In some centres, surgical planning and rehearsals are already being carried out at the computer terminal with the use of animation and computer graphics. Computer technology has also played an active role in the field of prosthetics and rehabilitation. Intelligent robotic systems and microprocessor with functional neuromuscular stimulation have been applied to benefit, and in some cases restore some motor functions to the physically disabled. With more collaboration between engineers, scientists and the medical community, several prototypes of computer-controlled prostheses and prosthesis designed and manufactured by Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) technology are available today to assist the amputees in their daily living and ambulatory activities.

Computer Graphics↗