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Biomedical subjects

P Y Kim

Publications and source records attributed to P Y Kim.

At least 19 recordsLinked to original sources
PubMed2001

Protective effect of green tea extract on ischemia/reperfusion-induced brain injury in Mongolian gerbils.

Free radical-induced oxidative damages of macromolecules and cell death are important factors in the pathogenesis of ischemia/reperfusion brain injury. In the present study, an investigation as to whether green tea extract reduces ischemia/reperfusion-induced brain injury in Mongolian gerbils was conducted. The effect of green tea on the ischemia/reperfusion-induced production of hydrogen peroxide, lipid peroxidation and oxidative DNA damage (formation of 8-hydroxydeoxyguanosine), and cell death in addition to locomotor activity was studied. Two doses (0.5 or 2%) of green tea extract were added into the drinking water and to be accessed by animals ad libitum for 3 weeks prior to the induction of ischemia. A global ischemia was induced by the bilateral occlusion of the common carotid arteries for 5 min. Reperfusion was achieved by releasing the occlusion and restoring blood circulation for 48 h. The infarction volumes were 112+/-31 mm(3) and 76+/-11 mm(3) in the 0.5 and 2% green tea pretreated animals compared to 189+/-12 mm(3) in the ischemia/reperfusion animals. Green tea extract also reduced the levels of ischemia/reperfusion-induced hydrogen peroxide (from 1470+/-170 to 1034+/-46 and 555+/-30 nmole/mg protein), lipid peroxidation products (from 1410+/-210 to 930+/-40 and 330+/-20 nmole/mg protein) and 8-oxodG (from 3.9+/-0.1 to 2.8+/-0.3 and1.9+/-0.3 ng/microg DNA, x10(-2)) by pretreatment of 0.5 or 2% green tea for 3 weeks, respectively. Moreover, green tea also reduced the number of ischemia/reperfusion-induced apoptotic cells (from 59+/-12 to 37+/-8, 15+/-11 apoptotic cells/high power field in the striatum region) and locomotor activity (from 15140+/-2940 to 3900+/-600 and 4100+/-1200). This study therefore suggests that green tea may be a useful agent for the prevention of cerebral ischemia damage.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

Involvement of cortical damage in the ischemia/reperfusion-induced memory impairment of Wistar rats.

The effect of ischemia/reperfusion-induced neuronal damage on the memory impairment were investigated using active avoidance and Morris water maze tasks in Wistar rats. Focal ischemia was induced by 1 h occlusion of the right middle cerebral artery (MCA) of Wistar male rats. Reperfusion was induced by releasing the occlusion and restoring the blood circulation for 24 h. The acquisition and preservation memory tested by active avoidance showed a significant difference between the sham and ischemia/reperfusion group. The water maze acquisition performance was also significant difference between sham and ischemia/reperfusion groups in both latency and moving distance. The infarction volume was increased by the ischemia/reperfusion. Furthermore, the cresyl violet staining of the ischemia/reperfusion brain showed severe neuronal damage (pyramidal cell loss) in the cortex in addition to the striatum lesion of brain. This study shows that pyramidal cell damage in the cortex lesion may be partially related to memorial disturbance in the ischemia/reperfusion brain injury.

Animals↗
PubMed2000

Mini-sternotomy for off-pump coronary artery bypass grafting.

The number of off-pump coronary artery bypass grafting procedures without cardiopulmonary bypass is steadily increasing. We report on a new, minimally invasive surgical approach for off-pump coronary revascularization in multivessel disease. A distal sternotomy is performed to gain access to the left and right internal thoracic arteries and to reach the left anterior descending coronary artery, diagonal branches, and right coronary artery for off-pump revascularization.

Coronary Artery Bypass↗
PubMed2000

Neuroprotective effect of green tea extract in experimental ischemia-reperfusion brain injury.

Eicosanoids accumulation and formation of oxygen free radicals have been implicated in the pathogenesis of ischemia/reperfusion brain injury. In the present study, we examined whether green tea extract protects against ischemia/reperfusion-induced brain injury by minimizing eicosanoid accumulation and oxygen radical-induced oxidative damage in the brain. Green tea extract (0.5%) was orally administered to Wistar rats for 3 weeks before induction of ischemia. Ischemia was induced by the occlusion of middle cerebral arteries for 60 min and reperfusion was achieved for 24 h. Infarction volume in the ipsilateral hemisphere of ischemia/reperfusion animals was 114 +/- 16 mm(3) in the 0.5% green tea pretreated animals compared to 180 +/- 54 mm(3) in left hemisphere of nontreated animals. Green tea extract (0.5%) also reduced ischemia/reperfusion-induced eicosanoid concentration: Leukotriene C(4) (from 245 +/- 51 to186 +/- 22), prostoglandin E(2) (from 306 +/- 71 to 212 +/- 43) and thromboxane A(2) (327 +/- 69 to 251 +/- 87 ng/mg protein). Ischemia/reperfusion-induced increases of hydrogen peroxide level (from 688 +/- 76 to 501 +/- 99 nmole/mg protein), lipid peroxidation products (from 1010 +/- 110 to 820 +/- 70 nmole/mg protein) and 8-oxodG formation (from 1.3 +/- 0.3 to 0.8 +/- 0.2 ng/microg DNA, x10(-2)) were also reduced. Moreover, 0.5% green tea extract also reduced the apoptotic cell number (from 44 +/- 11 to 29 +/- 1 in the striatum, and from 72 +/- 11 to 42 +/- 5 apoptotic cells/high power field in the cortex region). Green tea extract pretreatment also promoted recovery from the ischemia/reperfusion-induced inhibition of active avoidance. The present study shows that the minimizing effect of green tea extract on the eicosanoid accumulation and oxidative damage in addition to the reduction of neuronal cell death could eventually result in protective effect on the ischemia/reperfusion-induced brain injury and behavior deficit.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

In vitro cytotoxicity tests on cultured human skin fibroblasts to predict skin irritation potential of surfactants.

Cultured human skin cells are a potentially useful model for skin irritancy testing. We have investigated the use of human skin fibroblasts for in vitro screening for skin toxicity. To assess the cytotoxic effects of surfactants, cell viability was measured by the NRU (neutral red uptake) assay and AB (Alamar blue) assay as in vitro methods. The skin irritation potential of surfactants by human skin patch test was assessed as in vivo methods. The close relationship was found between AB assay with human skin fibroblasts and human patch test (r=0.867). There was a relatively good agreement between the NRU and in vivo patch test (r=0.648). These results suggest that AB and NRU assay using cultured human fibroblast could be predictable methods for the irritancy of various surfactants in human.

Adult↗
PubMed1999

Racial differences in prostate cancer related to loss of heterozygosity on chromosome 8p12-23.

PURPOSE: To determine if there is a racial difference in prostate cancer related to loss of heterozygosity (LOH) on chromosome 8p12-23, the region most frequently altered in prostate cancer. METHODS AND MATERIALS: A total of 51 prostate cancer patients, consisting of 23 African Americans and 28 Caucasians, were included in this study. All patients underwent radical prostatectomy, and patients in the two racial subgroups were matched for median serum PSA, Gleason score, and pathological stage of cancer. Paired normal prostate and cancer tissue DNA was isolated and amplified with 13 polymorphic markers mapped to 8p12-23 by radiolabeled polymerase chain reaction. The amplified products were resolved by polyacrylamide gel electrophoresis, autoradiographed, and analyzed for allelic losses. RESULTS: The overall incidence of LOH at 8p12-23 was 53%, and 16% showed homozygous deletions. The incidence of LOH in Caucasians was 68% compared to 35% in African Americans. On univariate (p = 0.02) and multivariate logistic regression analysis (p = 0.02), only Caucasian race was a significant predictor for LOH. The other clinicopathologic parameters did not have any significant effect on incidence of LOH. CONCLUSION: These results highlight the independent influence of Caucasian race on incidence of LOH at 8p12-23, and suggest that genetic differences at specific tumor suppressor loci may be a factor responsible for racial variations observed in prostate cancer.

Aged↗
PubMed1999

Different approaches for minimally invasive closure of atrial septal defects.

BACKGROUND: To improve the acceptance of cosmetic results after closure of atrial septal defects, anterior or lateral thoracotomies are preferred rather than median sternotomies. Along with the availability of minimally invasive techniques, a further reduction in incision length appeared feasible while preserving thoracic stability. METHODS: Various minimally invasive approaches differing in the type of incision and mode of cannulation have been applied under conditions of normothermic ventricular fibrillation. In technique 1 (n = 5), a right parasternal mini-incision was combined with a central aortic and bicaval cannulation. Technique 2 (n = 2) was composed of an anterior submammary mini-incision with femoral arterial and central bicaval cannulation. To optimize the surgical access, the transincisional cannulation of the superior vena cava was replaced by a percutaneous cervical cannulation (technique 3, n = 17). RESULTS: Effective atrial septal defect closure assessed by intraoperative echocardiography was achieved in all patients. Central neurologic complications were completely absent. Besides temporary atrial fibrillation in one case, no other cardiac complications occurred. There were no cases with complicated wound healing. CONCLUSIONS: Along with modified cannulation techniques and intraoperative echocardiography, minimally invasive techniques can be safely applied for atrial septal defect closure. Submammary incisions were highly accepted and allowed for adequate surgical exposure.

Adolescent↗
PubMed1999

Coronary revascularization without cardiopulmonary bypass in patients with pectus excavatum.

BACKGROUND: Coronary revascularization in patients with pectus excavatum is technically difficult through a median sternotomy secondary to the posterior displacement of the sternum and the asymmetric angulation that it produces. The role of minimally invasive coronary artery bypass grafting (MIDCABG) in this subset of patients was evaluated. METHODS: In 1998, four patients with pectus excavatum underwent revascularization of the left anterior descending artery without cardiopulmonary bypass through a left anterior minithoracotomy. RESULTS: All patients underwent the procedure without intraoperative complications and postoperative angiography demonstrated adequate graft patency. CONCLUSIONS: The advantages of MIDCABG in patients with pectus excavatum is the superior exposure to the LAD and LIMA and avoidance of a median sternotomy and cardiopulmonary bypass. This procedure is deemed safe and effective in patients with such deformities of the chest wall.

Cardiopulmonary Bypass↗
PubMed1998

Cervical cancer with paraaortic metastases: significance of residual paraaortic disease after surgical staging.

Cervical carcinoma frequently metastasizes to the paraaortic region, necessitating extended field radiotherapy to effect a cure. As imaging modalities are unreliable in identifying all cases of paraaortic nodal metastases (PAN), surgical staging is often utilized prior to radiotherapy. This study was aimed at identifying factors predictive of survival in women with cervical carcinoma and paraaortic metastases. In particular, survival based on extent of paraaortic disease was examined. The study group consisted of 43 women (stages IB-IVB) identified between 1982 and 1993 who were treated with extended field radiation for cervical carcinoma with histologically confirmed paraaortic metastases. The estimated 5-year survival for the study population was 24% with a median survival of 18 months. Pelvic tumor size had a significant impact on survival with the median survival being 34 months if the primary lesion was < 6 cm compared to 14 months if > or = 6 cm (P = 0.01). Eight of the 26 (31%) women without residual PAN disease after surgical staging remain alive and disease free (mean follow-up, 74 months). In contrast, only 1 of the 17 (6%) women with gross residual PAN is alive 71 months after treatment (P = 0.05). However, a comparison of Kaplan-Meier survival curves did not show a statistically significant advantage to the surgical excision of grossly involved PAN (P = 0.98). Although long-term survival among women with grossly involved, unresected paraaortic metastases is uncommon, further study is necessary to elucidate the role of surgical excision of bulky aortic disease in women with cervical cancer.

Adenocarcinoma↗
PubMed1998

A new minimally invasive approach to the subclavian artery.

Aneurysms of the subclavian artery are rare. We report a case in which an aneurysm of the right subclavian artery presented as localized atrophy of the deltoid muscle. Operative repair was accomplished by a new minimally invasive surgical approach.

Adult↗
PubMed1997

Butch, femme, or straight acting? Partner preferences of gay men and lesbians.

On average, gay men are somewhat feminine and lesbians somewhat masculine, but there is variation within each group. The authors examined the consequences of this variation for gay men's and lesbians' desirability as romantic partners. In 2 studies the authors analyzed personal advertisements. Homosexual people were more likely than heterosexual people to mention traits related to sex typicality and more likely to request sex-typical than sex-atypical partners. In 2 studies the authors assessed partner preferences directly. On average, gay men preferred men who described themselves as masculine rather than feminine, but this preference was weaker among men who rated themselves as relatively feminine. Lesbians preferred women who described themselves as feminine looking but did not discriminate against women calling themselves masculine acting. The authors discuss implications of the results for theories of sexual orientation and the adjustment of sex-atypical homosexual people.

Adult↗
PubMed1994

Coordinate depression of bradykinin receptor recycling and microtubule-dependent transport by taxol.

Significant cardiovascular side effects have limited the use of taxol as an anticancer drug. A link between decreased plasma membrane dynamics and taxol has been implied because taxol can inhibit intracellular vesicle movements. Reduced membrane recycling caused by taxol could inhibit agonist-evoked Ca2+ signaling within endothelial cells, resulting in endothelium-dependent vasodilation. Bradykinin and ATP are two agonists that evoke Ca2+ transients in endothelial cells. Since the bradykinin receptor-agonist complex is internalized and recycled whereas the ATP agonist-receptor complex is not, we expected that a taxol inhibition of recycling would decrease bradykinin but not ATP receptor activity. We found that taxol depresses (i) the frequency (to 41% of control) and velocity (to 55% of control) of microtubule-dependent vesicle transport and (ii) bradykinin-evoked cytosolic Ca2+ transients (to 76% of control) in bovine aortic endothelial cells. In studying bradykinin receptor desensitization, which reflects receptor recycling, we demonstrate that taxol inhibits bradykinin-evoked Ca2+ transients by 50%. Taxol did not significantly alter ATP-evoked Ca2+ transients in either single-exposure or desensitization experiments. We suggest that taxol's reduction of bradykinin-evoked Ca2+ transients is due to altered microtubule-dependent membrane recycling. This report describes taxol's ability to alter plasma membrane composition through effects on vesicle transport and membrane trafficking pathways. This finding provides a possible mechanism by which taxol can substantially alter cardiovascular function.

Adenosine Triphosphate↗
PubMed1993

Regulation of vesicle transport in CV-1 cells and extracts.

To investigate the regulation of microtubule-dependent vesicle motility, we have studied the effects of pharmacological agents on the frequency and velocity of small vesicle movements in intact CV-1 cells. Nocodazole, but not cytochalasin B or D, abolished vesicle movements, indicating that these movements were microtubule and not actin-dependent. The frequency of vesicle movements was stimulated maximally sixfold by okadaic acid from a resting value of 1.6 movements/min per microns2 in serum-starved CV-1 cells. Other activators in decreasing order of effectiveness are fetal calf serum, dibutyryl cAMP, cholera toxin, genistein, A23187, and trental. On the other side, taxol inhibited vesicle movements by a factor of four. The activators, okadaic acid, fetal calf serum, and dibutyryl cAMP, also increased vesicle velocity and run length, while taxol decreased vesicle velocity. Although modulation of the frequency of vesicle movements over a > 20-fold range was observed, under all conditions the fraction of vesicles moving inward versus outward did not significantly change. Only in the case of taxol was the distribution of microtubules altered within this same time period. Both inward and outward microtubule-dependent vesicle movements therefore appear to be coordinately regulated. The enhanced vesicle motility elicited by fetal calf serum in intact cells correlated with in vitro measurements of vesicle motility and velocity on purified microtubules using microtubule affinity-purified motors and carbonate-washed vesicles from cells treated with fetal calf serum. This suggests that the amount of vesicular intracellular membrane traffic is coordinately regulated with microtubule-dependent motor activity.

Adenylyl Cyclases↗
PubMed1992

Defining the dose range for esmolol used in electroconvulsive therapy hemodynamic attenuation.

We evaluated the clinical effectiveness of esmolol, an ultra-short-acting, beta-adrenergic receptor blocking drug, to control the sinus tachycardia and increase in arterial blood pressure induced by electroconvulsive therapy (ECT). Each of 20 patients, ASA physical status I-III, participated in a double-blind, randomized Latin-Square study involving two matched-pair trials (placebo versus esmolol given as a 500-micrograms/kg bolus followed by either 300 micrograms.kg-1.min-1 [high dose], 200 micrograms.kg-1.min-1 [medium dose], or 100 micrograms.kg-1.min-1 [low dose] infusion of esmolol) during ECT. Each patient acted as his or her own control (total number of ECT procedures were 160). We administered a 1-min bolus of placebo (normal saline) or esmolol at the rate of 500 micrograms.kg-1.min-1 followed by either high-, medium-, or low-dose esmolol or placebo for an additional 3 min. We then induced anesthesia with methohexital (1 mg/kg) and succinylcholine (0.5 mg/kg) IV. Ninety seconds after the administration of succinylcholine, the electrical stimulus was applied to induce seizure. The infusion of placebo or esmolol was discontinued 3 min after the electrical stimulus. Significant decreases were found in mean heart rate from minute 3 until minute 7 and in the maximum heart rate. The mean of each patient's maximum heart rate after seizure changed from 147 +/- 18 bpm in placebo patients to 112 +/- 20 bpm in high-dose esmolol patients; to 121 +/- 23 bpm in medium-dose esmolol patients; and to 124 +/- 20 bpm in low-dose esmolol patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1991

Behavioral teratogenicity of methamphetamine.

Pregnant Wistar rats were given daily subcutaneous administrations of methamphetamine (MAPT; varying doses ranging from 1.0 to 4.5 mg/kg) from days 7 to 20 of gestation and teratogenic effects have been determined. The teratogenic effects inducible with orally administered caffeine (90 mg/kg/day) for the same durations were used as the positive controls. MAPT doses greater than 2.0 mg/kg have suppressed the rate of maternal weight gain. Some of the offsprings (F1) of the prenatal MAPT treated groups had decreased growth rate and delayed development of physical characters and functional reflexes. The male offsprings of the MAPT treated groups had significant decreases in their spontaneous motor activity but had enhanced conditioned avoidance responses. However, the mating performances of these offsprings were not affected. These results indicated that prenatal exposure of MAPT may induce some behavioral teratogenicity in rats.

Animals↗