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Biomedical subjects

K S Cho

Publications and source records attributed to K S Cho.

At least 19 recordsLinked to original sources
PubMed2005

Histopathological and behavioral characterization of a novel cervical spinal cord displacement contusion injury in the rat.

Cervical contusive trauma accounts for the majority, of human spinal cord injury (SCI), yet experimental use of cervical contusion injury models has been limited. Considering that (1) the different ways of injuring the spinal cord (compression, contusion, and transection) induce very different processes of tissue damage and (2) the architecture of the spinal cord is not uniform, it is important to use a model that is more clinically applicable to human SCI. Therefore, in the current study we have developed a rat model of contusive, cervical SCI using the Electromagnetic Spinal Cord Injury Device (ESCID) developed at Ohio State University (OSU) to induce injury by spinal cord displacement. We used the device to perform mild, moderate and severe injuries (0.80, 0.95, and 1.1 mm displacements, respectively) with a single, brief displacement of <20 msec upon the exposed dorsal surface of the C5 cervical spinal cord of female (180-200 g) Fischer rats. Characterization of the model involved the analysis of the temporal histopathological progression of the injury over 9 weeks using histochemical stains to analyze white and gray mater integrity and immunohistochemistry to examine cellular changes and physiological responses within the injured spinal cord. Accompanying the histological analysis was a comprehensive determination of the behavioral functionality of the animals using a battery of motor tests. Characterization of this novel model is presented to enable and encourage its future use in the design and experimental testing of therapeutic strategies that may be used for human SCI.

Animals↗
PubMed2002

Significance of temperature difference between cerebral cortex and axilla in patients under hypothermia management.

It is believed that the brain temperature is about 1 degree C higher than the other peripheral temperature. But the result has been mostly obtained in normothermia patients. The objective of this study was to evaluate whether the brain temperature is still higher than the axillary one in the hypothermia patients. Sixty-three patients who underwent craniotomy with implantation of the thermal diffusion thermometer were included in this study. Fifty-four patients were in normothermia and nine patients were managed with mild to moderate hypothermia (about 32 degrees C). The temperature of the cerebral cortex and axilla was measured simultaneously every 2 hours. 1900 paired sample data were collected and analyzed. The temperature difference between the cerebral cortex and the axilla was 1.04 +/- 0.67 degrees C in normothermia patients and 0.91 +/- 0.84 degree C in hypothermic patients. The temperature difference has no statistical significance between the two groups (unpaired t-test, P > 0.05). Our results demonstrate that the brain temperature in the patients under hypothermia management appears to be still about 1 degree C higher than the axilla throughout the study period almost in the same fashion as in normothermia patients.

Adolescent↗
PubMed2001

Diptericin-like protein: an immune response gene regulated by the anti-bacterial gene induction pathway in Drosophila.

Insects produce various anti-microbial peptides in response to injury and infection. In Drosophila, diptericin has previously been studied as an anti-bacterial immune response gene. Here, we report the cloning of the diptericin-like protein (dptlp) gene as a paralog of Drosophila diptericin. By comparison of their sequences, we found that the dptlp gene has all of the functional domains conserved in the diptericin gene and other anti-bacterial proteins. The dptlp gene was rapidly induced by bacterial infections and showed different time-dependent gene expression patterns from those of diptericin. Like diptericin, dptlp was specifically produced from the fat body, and its expression was strictly dependent on bacterial infections. In addition, the dptlp gene expression was almost completely abolished in the imd mutant, which implicates that its expression is regulated by the anti-bacterial arm of the Drosophila innate immune regulatory pathways. In support of this, we found GATA, interferon consensus responding element, and kappa B binding sites, which is known to be important for the proper expression of anti-bacterial genes, in the proximal promoter region of the dptlp gene. Taken together, our findings support that dptlp is a novel anti-bacterial peptide whose expression is regulated by the anti-bacterial immune response mechanism.

Amino Acid Sequence↗
PubMed2001

Drosophila phosphoinositide-dependent kinase-1 regulates apoptosis and growth via the phosphoinositide 3-kinase-dependent signaling pathway.

Phosphoinositide-dependent kinase-1 (PDK-1) is a central mediator of the cell signaling between phosphoinositide 3-kinase (PI3K) and various intracellular serine/threonine kinases including Akt/protein kinase B (PKB), p70 S6 kinases, and protein kinase C. Recent studies with cell transfection experiments have implied that PDK-1 may be involved in various cell functions including cell growth and apoptosis. However, despite its pivotal role in cellular signalings, the in vivo functions of PDK-1 in a multicellular system have rarely been investigated. Here, we have isolated Drosophila PDK-1 (dPDK-1) mutants and characterized the in vivo roles of the kinase. Drosophila deficient in the dPDK-1 gene exhibited lethality and an apoptotic phenotype in the embryonic stage. Conversely, overexpression of dPDK-1 increased cell and organ size in a Drosophila PI3K-dependent manner. dPDK-1 not only could activate Drosophila Akt/PKB (Dakt1), but also substitute the in vivo functions of its mammalian ortholog to activate Akt/PKB. This functional interaction between dPDK-1 and Dakt1 was further confirmed through genetic analyses in Drosophila. On the other hand, cAMP-dependent protein kinase, which has been proposed as a possible target of dPDK-1, did not interact with dPDK-1. In conclusion, our findings provide direct evidence that dPDK-1 regulates cell growth and apoptosis during Drosophila development via the PI3K-dependent signaling pathway and demonstrate our Drosophila system to be a powerful tool for elucidating the in vivo functions and targets of PDK-1.

3-Phosphoinositide-Dependent Protein Kinases↗
PubMed2001

Sonographic findings in solitary schwannoma of the breast.

Solitary schwannoma is a benign neoplasm of Schwann cell origin, most frequently occurring in the extremities and the trunk and head regions. The breast is a very unusual site for this tumor. We report a case of benign schwannoma of the breast in a 76-year-old woman. The palpable mass was localized in the lower outer quadrant of the right breast. This intramammary schwannoma appeared sonographically as a well-circumscribed, hypoechoic, slightly inhomogeneous solid mass. Microscopically, it had a pattern similar to that of schwannoma at other sites.

Aged↗
PubMed2001

Two-dimensional electrophoretic analysis of rice proteins by polyethylene glycol fractionation for protein arrays.

Two-dimensional electrophoresis (2-DE) is known as the most effective as well as one of the simplest methods for separating proteins. However, a few hundred plant leaf proteins out of thousands visualized on a 2-DE gel can be identified by chemical analysis due to the presence of ribulose bisphosphate carboxylase/oxygenase (Rubisco) that limits protein loading. We describe the extraction and fractionation technique with polyethylene glycol (PEG) to analyze rice leaf proteins. Rice proteins were extracted with Mg/NP-40 extraction buffer. The Mg/Nonidet P-40 (NP-40) buffer extract was further fractionated with PEG into three fractions: 10% PEG and 10-20% PEG precipitants and the final supernatant fraction that was precipitated with acetone. Rubisco, the most abundant rice leaf protein, was enriched in the 20% PEG precipitant. This fractionation technique analyzed at least 2,600 well-separated protein spots and exhibited less than 1.2% of noticeable overlapping spots. An immunological approach was used to verify the efficiency whether PEG fractionation technique can detect or enrich signal transduction components such as Galpha, ADP ribosylation factor, small GTP binding protein and 14-3-3. The ADP ribosylation factor (ARF) and Galpha were only detected in the PEG supernatant fraction not in the total protein fraction. The small GTP binding protein (Rab 7) was identified in the 10% PEG fraction and only faintly in the total protein fraction. The 14-3-3 protein was detected in all fractions but was especially prevalent in the 20% PEG fraction.

Blotting, Western↗
PubMed2001

Evaluation of occupational health service systems in small- and medium-sized industries in Korea.

OBJECTIVES: To establish a system of analytical methodology that can be used to evaluate an occupational health service system, to evaluate the performance of different types of the system in small- and medium-sized industries using the evaluation model, and to identify factors which influence the performance of an occupational health service system. METHODS: The input-output-outcome aspects of two different systems, capitation-based Group health services and fee-for-service-based Individual health services, were examined, based on a causal model. Each causal relationship in the model was tested for its statistical significance by the linear regression technique based on the ordinary least square method. Data from 16 enterprises in the Group-type, 17 enterprises in the Individual-type, and 32 enterprises in the Transitional Group-type were used in the analyses. RESULTS: In the Group model, enterprises utilized fewer resources for occupational services, their workers were provided with more services when services such as medical examinations were supplied directly by the system, and they had worse outcome measures of health and industrial injuries. The latter was the result of less input and fewer services, the supply of which was not within the direct control of the system, such as compliance with the recommendation to install machine safety devices and the proper maintenance and operation of these devices. CONCLUSIONS: Although study results revealed problem areas in the performance of the Group system, the study found a potential for an effective and efficient system in the Group-type with efforts geared to the better follow-up of work environment problems.

Humans↗
PubMed2001

Effects of hand massage on anxiety in cataract surgery using local anesthesia.

PURPOSE: To evaluate the effects of hand massage on patient anxiety during cataract surgery. SETTING: Kangnam St. Mary's Hospital, Seoul, Korea. METHODS: This study comprised 59 patients having cataract surgery from December 11, 1996, to February 12, 1997. The patients were divided into those having a hand massage 5 minutes before surgery (experimental group, n = 29) and those not receiving a hand massage (control group, n = 30). Patients' anxiety levels were measured using the Visual Analog Scale and by assessing the systolic blood pressure, diastolic blood pressure, and pulse rate before and after the hand massage and 5 minutes before the end of surgery. Epinephrine, norepinephrine, cortisol, blood sugar levels, neutrophil, and lymphocyte percentages in white blood cells were also measured. RESULTS: After the hand massage, the psychological anxiety levels, systolic and diastolic blood pressures, and pulse rate were significantly lower than before the massage. The hand massage significantly decreased epinephrine and norepinephrine levels in the experimental group. Epinephrine, norepinephrine, and cortisol levels increased in the control group. The differences between groups were significant. There were no significant between-group differences in blood sugar levels or neutrophil and lymphocyte percentages in white blood cells. CONCLUSION: The findings indicate that hand massage decreases the psychological and physiological anxiety levels in patients having cataract surgery under local anesthesia.

Adult↗
PubMed2001

Differential effects of intravitreal optic nerve and sciatic nerve grafts on the survival of retinal ganglion cells and the regeneration of their axons.

We have investigated the effects of intravitreal sciatic nerve (SN) and/or optic nerve (ON) grafts on the survival and the axonal regeneration of retinal ganglion cells (RGCs). Following transection of the ON, approximately 40% RGCs survived at 7 days post-axotomy (dpa). Results showed that the intravitreal ON graft significantly promoted the survival of RGCs at 7 dpa (39,063 vs 28,246). Intravitreal SN graft, however, did not rescue axotomized RGCs at 5, 7 or 14 dpa. Axotomized RGCs could be induced to regenerate axons along a segment of SN graft attached to the proximal stump of ON. On average, 608 axotomized RGCs were induced to regenerate axons along the attached SN graft. The presence of intravitreal SN graft promoted about 100% increase in the number of regenerating RGCs (1,227) relative to the control groups. The intravitreal ON graft, surprisingly, also induced about 100% more regenerating RGCs (1220) than in the control group. When SN and ON grafts were co-transplanted into the vitreous, about 200% more regenerating RGCs (1916) were observed than in the control group. These findings illustrated that the intravitreal ON graft rescued axotomized RGCs and enhanced the regeneration of retinal axons. This is the first report to show that ON promotes RGC axonal regeneration. The intravitreal SN graft did not rescue RGCs but promoted axonal regeneration. The differential effects of intravitreal ON and SN grafts on the survival and the RGC regeneration suggest that these might be two independently operating events.

Animals↗
PubMed2001

The effects of handholding on anxiety in cataract surgery patients under local anaesthesia.

AIM OF THE STUDY: To assess the effectiveness of handholding on the anxiety of patients undergoing planned cataract surgery under local anaesthesia. BACKGROUND: Anxiety concerning anaesthesia, pain, physical injuries, isolation, prognosis, possibilities of deformity, or loss of self-control may be stressful to patients undergoing surgery. Anxiety activates the sympathetic nervous system, characterized by an increase in catecholamine concentration, heart rate and blood pressure and increased glucocorticoid levels; it also affects immune responses. Therefore, there is a need for nursing interventions to reduce the anxiety of patients under local anaesthesia who are conscious. METHODS: An untreated control group design with pre and post-test was used. Among 62 patients, 30 were randomly assigned to the handholding group and 32 to the control group. Handholding was provided to subjects of the handholding group during surgery. Visual analogue scales and interviews were used to measure anxiety, and pulse rate and systolic and diastolic blood pressure were used as physiological measures of stress. Blood was taken for analysis of levels of epinephrine, norepinephrine, cortisol, neutrophils, lymphocytes and natural killer cells. RESULTS: The number of subjects who reported decreased anxiety during operation was significantly higher in the handholding group compared with the control group and most of the subjects reported that handholding during operation was very helpful in reducing anxiety. Epinephrine levels in the handholding group were significantly lower than in the control group. CONCLUSIONS: Results suggest that this noninvasive intervention has potential for reducing anxiety in patients having cataract surgery under local anaesthesia.

Adult↗
PubMed2001

Sorption and biodegradation of vapor-phase organic compounds with wastewater sludge and food waste compost.

To test the possible use of composted food waste and wastewater sludge as biofilters to treat gas-phase volatile organic compounds (VOCs), batch experiments were conducted with an isolated strain that could degrade aromatic compounds under aerobic conditions. A benzene and trichloroethylene (TCE) mixture was used as the gas-phase pollutant in experiments with composted food waste, sludge, and soil. Under aerobic conditions, benzene was degraded as a primary substrate and TCE was degraded cometabolically, with water contents varying from 6 to 60% (volume of water added/volume of solid). Optimal water content for VOC removal was 12% for the soil, 36% for the composted food waste, and 48% for the sludge. The extent of VOC sorption and biodegradation at the optimal water content was different for each material. With the same initial VOC concentration, more VOCs were removed by sorption onto the composted food waste and the sludge, while less VOCs were biodegraded in comparison with the results using soil. The reason the biodegradation in the soil was greater may be partly attributed to the fact that, due to less sorption, the aqueous-phase concentration of VOCs, which microorganisms could utilize as a carbon source or cometabolize, was higher. We also speculate that the distribution of microorganisms in each medium affects the rate of biodegradation. A large number of microorganisms were attached to the composted food waste and sludge. Mass transfer of VOCs and oxygen to these microorganisms, which appear to have been heterogeneously distributed in clusters, may have been limited, resulting in hindered biodegradation.

Adsorption↗
PubMed2001

Electrochemical remediation of trichloroethene-contaminated groundwater using palladized iron oxides.

The objective of this study is to develop electrochemically-enhanced dechlorination of trichloroethene (TCE) using palladized iron oxides minerals for ex situ remediation of contaminated groundwaters. A bench-scale column packed with the palladized iron oxide media connected to a cathode and an anode embedded in a carbon pad was prepared for flow through column tests. Contaminated groundwaters with about 14-16 mg/L TCE were passed from the cathode side to the anode side of the column while the system was supplied with direct current. All of the TCE in the groundwater was dechlorinated even after 300 pore volumes were passed. Furthermore, intermediate reaction products, dichloroethene isomers and vinyl chloride, were not detected in the treated water.

Electrochemistry↗
PubMed2001

Akt/PKB promotes cancer cell invasion via increased motility and metalloproteinase production.

The Akt/protein kinase B (PKB) serine/threonine kinase is well known as an important mediator of many cell survival signaling pathways. Here, we demonstrate for the first time a major role of Akt/PKB in the cell invasion properties of the highly metastatic cell line HT1080. Using confocal microscopic analyses of live samples, we found Akt/PKB to be localized in the leading edge membrane area of migrating HT1080 cells. This localization was dependent on phosphoinositide 3-kinase and required the lipid binding ability of the phosphoinositide binding pleckstrin homology domain of Akt/PKB. We examined the possible function of Akt/PKB in HT1080 invasion. Surprisingly, Akt/PKB potently promoted HT1080 invasion, by increasing cell motility and matrix metalloproteinase-9 (MMP-9) production, in a manner highly dependent on its kinase activity and membrane-translocating ability. The increase in MMP-9 production was mediated by activation of nuclear factor-kappaB transcriptional activity by Akt/PKB. However, Akt/PKB did not affect the cell-cell or cell-matrix adhesion properties of HT1080. Our findings thus establish Akt/PKB as a major factor in the invasive abilities of cancer cells.

Cell Adhesion↗
PubMed2001

Abdominopelvic actinomycosis involving the gastrointestinal tract: CT features.

PURPOSE: To assess the computed tomographic (CT) features of abdominopelvic actinomycosis involving the gastrointestinal tract. MATERIALS AND METHODS: CT scans were analyzed in 18 patients with pathologically proved abdominopelvic actinomycosis involving the gastrointestinal tract. Eight patients had a history of using intrauterine contraceptive devices. Bowel site, wall thickness, length, bowel involvement patterns, inflammatory infiltration, and features of peritoneal or pelvic mass, if present, were evaluated at CT. RESULTS: Of the gastrointestinal tract, the sigmoid colon was most commonly involved (50%). All patients showed concentric (n = 15) or eccentric (n = 3) bowel wall thickening, with a mean thickness of 1.2 cm and a mean length of 8.3 cm. The thickened bowel enhanced homogeneously in nine patients and heterogeneously in the other nine. Inflammatory infiltration was mostly diffuse and severe. In 17 patients, a peritoneal or pelvic mass (mean maximum diameter, 3.2 cm) was seen adjacent to the involved bowel and appeared to be heterogeneously enhanced in most cases; infiltration into the abdominal wall was seen in four patients. CONCLUSION: Actinomycosis should be included in the differential diagnosis when CT scans show bowel wall thickening and regional pelvic or peritoneal mass with extensive infiltration, especially in patients with abdominal pain, fever, leukocytosis, or long-term use of intrauterine contraceptive devices.

Actinomycosis↗
PubMed2001

Cigarette smoking negatively affects healing response following flap debridement surgery.

BACKGROUND: The purpose of the present parallel design, controlled clinical trial was to evaluate the treatment outcome following flap debridement surgery (FDS) in cigarette smokers compared to non-smokers. METHODS: After initial therapy, 57 systemically healthy subjects with moderate to advanced periodontitis who presented with one area (at least 3 teeth) where surgery was required were selected. Twenty-eight patients (mean age: 39.6 years, 20 males) were smokers (> or = 10 cigarettes/day); 29 patients (mean age: 43.9 years, 7 males) were non-smokers. Full-mouth plaque (FMP) and bleeding on probing (BOP) scores, probing depth (PD), clinical attachment level (CAL), and recession depth (RD) were assessed immediately before and 6 months following surgery. Only sites with presurgery PD > or = 4 mm were used for statistical analysis. RESULTS: Presurgery FMP and BOP were similar in smokers and non-smokers and significantly decreased postsurgery in both groups. Overall, PD reduction and CAL gain were greater, although not significantly, in non-smokers (2.4 +/- 0.9 mm and 1.6 +/- 0.7 mm, respectively) than in smokers (1.9 +/- 0.7 mm and 1.2 +/- 0.7 mm, respectively). For moderate sites (PD 4 to 6 mm), no significant differences in PD and CAL changes were found between groups. For deep sites (PD > or = 7 mm), PD reduction was 3.0 +/- 1.0 mm in smokers and 4.0 +/- 0.8 mm in non-smokers, and CAL gain amounted to 1.8 +/- 1.1 mm in smokers and 2.8 +/- 1.0 mm in non-smokers (P = 0.0477). In smokers, 16% of deep sites healed to postsurgery PD values < or = 3 mm as compared to 47% in non-smokers (P = 0.0000); 58% of deep sites in smokers showed a CAL gain > or = 2 mm, as compared to 82% in non-smokers (P = 0.0000). CONCLUSIONS: Results of the study indicated that: 1) FDS determined a statistically significant PD reduction and CAL gain in patients with moderate to advanced periodontitis; 2) smokers exhibited a trend towards less favorable healing response following FDS compared to non-smokers, both in terms of PD reduction and CAL gain; and 3) this trend reached clinical and statistical significance at sites with initial deep PD.

Adult↗
PubMed2001

Activation of matrix metalloproteinase-2 by a novel oral spirochetal species Treponema lecithinolyticum.

BACKGROUND: Periodontal tissue destruction is a characteristic of periodontitis. This can be caused by either bacterial enzymes or host cell-derived matrix metalloproteinases (MMPs). In order to elucidate the etiologic role of oral spirochetes, we investigated the effects of Treponema lecithinolyticum, a novel saccharolytic species, on MMP-2 activation. METHODS: Gingival fibroblasts (GFs) and periodontal ligament (PDL) cells obtained from healthy human subjects were cultured to confluence in alpha-minimal essential medium (alpha-MEM) supplemented with 10% fetal bovine serum. After serum starvation for a day, the cultures were treated with whole cell sonicates, heat-denatured whole cell sonicates, outer membrane fraction (OMF) or formaldehyde-fixed cells of T. lecithinolyticum. Culture supernatants were collected after incubation for 24 to 48 hours and analyzed for MMP-2 activation by gelatin zymography. Collagenolytic activity was quantitatively measured using human [3H] type IV collagen as a substrate. RESULTS: Treatment of GFs and PDL cells with whole cell sonicates, formaldehyde-fixed whole cells, or the OMF of T. lecithinolyticum resulted in the production of MMP-2 partly in the fully active form with a molecular mass of 62 kDa, whereas non-treated control cultures and cultures treated with a heat-denatured fraction did not show the active form. Cultures exposed to T. lecithinolyticum had higher collagenolytic activity than non-treated cultures. CONCLUSIONS: Our results demonstrate that T. lecithinolyticum, possibly mediated by proteinaceous cell surface-associated components, may participate in extracellular matrix degradation by activation of MMP-2 during periodontal inflammation.

Animals↗