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Biomedical subjects

J Y Kwon

Publications and source records attributed to J Y Kwon.

24 records · Page 2Linked to original sources
PubMed1998

Riluzole does not attenuate increases in hippocampal glutamate concentrations in a rabbit model of repeated transient global cerebral ischemia.

UNLABELLED: The aim of the present study was to examine the ability of riluzole to inhibit glutamate release during episodes of transient global cerebral ischemia. New Zealand White rabbits (n = 36) were anesthetized with halothane and mechanically ventilated to maintain normocarbia. Microdialysis catheters were inserted bilaterally into the dorsal hippocampus and perfused with artificial cerebrospinal fluid at 2 microL/min. Animals were randomly assigned to control, hypothermia (30 degrees C), or riluzole (2 or 8 mg/kg; R2 and R8) groups. Two episodes of transient global cerebral ischemia (each lasting 10 min) were produced by inflating the pneumatic tourniquet combined with induced hypotension. Dialysate was collected throughout the periischemic period, and glutamate concentrations were determined by using high-performance liquid chromatography. Peak levels were compared by using the Kruskal-Wallis test. Glutamate concentrations significantly increased by twofold to fourfold during the second ischemic period for the control, R2, and R8 groups. Glutamate concentrations in the hypothermic group were significantly lower than those in the other three groups and remained at baseline levels during the entire experiment. This study demonstrates that the sodium channel blocker riluzole does not inhibit ischemia-induced glutamate accumulation. The previously reported neuroprotective ability of riluzole may be caused by mechanisms other than the presynaptic inhibition of glutamate release during ischemia. IMPLICATIONS: Glutamate, an excitatory neurotransmitter, is released in excessive amounts during brain ischemia and may result in neuronal injury and death. Riluzole, a neuronal sodium channel blocker, has neuroprotective properties in some animal models of brain ischemia, possibly because of its ability to inhibit the release of glutamate from synaptic vesicles. However, this microdialysis study failed to demonstrate any attenuation of glutamate release during transient global ischemia after the administration of either 2 mg/kg or 8 mg/kg of riluzole.

Animals↗
PubMed1998

Effects of temperature on cerebral tissue oxygen tension, carbon dioxide tension, and pH during transient global ischemia in rabbits.

BACKGROUND: A decrease in brain temperature (Tbrain) causes a decrease in the cerebral metabolic rate for oxygen (CMRO2) and provides potent neuroprotection against ischemic damage. In the present study, the effects of mild to moderate hypothermia on cerebral tissue oxygen tension (PO2 brain), carbon dioxide tension (PCO2 brain), and pH (pHbrain) were monitored during short episodes of global cerebral ischemia. METHODS: After approval by the Animal Care and Use Committee, 10 New Zealand white rabbits were anesthetized (1% halothane in air) and mechanical ventilation was adjusted to maintain the arterial carbon dioxide tension at 35 mmHg (alpha-stat). A sensor to measure PO2 brain, PCO2 brain, pHbrain, and Tbrain was inserted into the brain through a burr hole in the skull. Tbrain was adjusted to 38 degrees C, 34.4 degrees C, and 29.4 degrees C in a random sequence in each animal. PO2 brain, PCO2brain, and pHbrain (all variables are reported at the actual Tbrain) were recorded every 10 s during a 5-min baseline, 3 min of cerebral ischemia induced by inflation of a neck tourniquet, and 10 min of reperfusion at each level of Tbrain. Analysis of variance and Dunnett's test were used for statistical analysis. Data are presented as means +/- SD. RESULTS: During ischemia, PO2 brain decreased from 56 +/- 3 to 33 +/- 2 mmHg at 38 degrees C, from 58 +/- 3 to 32 +/- 3 mmHg at 34.4 degrees C, and from 51 +/- 2 to 32 +/- 2 mmHg at 29.4 degrees C (p = NS). PCO2 brain increased by 6.7 +/- 2 mmHg at 38 degrees C, by 5.1 +/- 1.4 mmHg at 34.4 degrees C, and by 2.3 +/- 0.8 mmHg at 29.4 degrees C. pHbrain inversely followed the trend of PCO2 brain. CONCLUSIONS: The attenuated increase in PCO2 brain during hypothermic ischemia results from the reduced CMRO2. The similar decrease in PO2 brain at all temperature levels indicates that despite the reduction in CMRO2, PO2 brain is no better preserved during brief episodes of hypothermic ischemia than during normothermic ischemia.

Analysis of Variance↗
PubMed1998

Detection and identification of proteins related to the hereditary dwarfism of the rdw rat.

Proteins having relations to hereditary dwarfism of the rdw rat (gene symbol: rdw) were searched for in various tissues of the rat with an improved two-dimensional gel electrophoresis technique followed by immunoblotting and microsequencing. Tissues inspected were cerebral cortex, cerebellum, brain trunk, hypothalamus, pituitary, thyroid gland, liver, testis, spleen, and thymus. Only pituitary and thyroid glands among those tissues showed abnormalities in protein contents. GH and PRL contents in the rdw pituitary were much less than in the normal one, which in the former were 1/15 and less than 1/30 times as much as in the latter, respectively, but the abnormalities in the rdw thyroid were far more serious than in the pituitary. At least 18 protein levels in the rdw thyroid were above, and 17 were below the normal. Those identified among the increased proteins were endoplasmin (GRP94), immunoglobulin heavy chain binding protein (BiP/GRP78), and heat shock protein 70 (hsp70), the contents of which respectively were 40 times, 10 times and more than 50 times as much in the rdw thyroid as in the normal tissue. Because BiP and endoplasmin are known to be ER resident proteins, and because all three belong to a chaperone protein family, accumulation of these proteins in the rdw thyroid suggests that protein folding and secreting disorders underlie the hypothyroidism of the rdw rat.

Animals↗
PubMed1997

Colonization rates and serotypes of group B streptococci isolated from pregnant women in a Korean tertiary hospital.

In a study designed to provide data on the rates of maternal carriage of group B streptococci (GBS) in Korean women, vaginal, anorectal, and urethral swab specimens from 459 pregnant women and ear canal and umbilicus swabs from their 288 neonates were cultured with new Granada medium and selective Todd-Hewitt broth. Additionally, the serotypes of 64 isolates of GBS and the minimal inhibitory concentrations of seven antimicrobial agents for these isolates were determined. The rate of colonization by GBS in pregnant women and in their babies was 5.9% (27/459) and 0.7% (2/288), respectively. The rates of resistance of GBS isolated from pregnant women were 13.3% to clindamycin, 5% to erythromycin, and 98.3% to tetracycline. The majority of GBS isolates from pregnant women belonged to serotypes Ib (48.3%), Ia (24.1%), and III (20.7%).

Adolescent↗
PubMedDate not supplied

Postoperative adjuvant therapy in early invasive cervical cancer patients with histopathologic high-risk factors.

The purpose of this study is to evaluate the efficacy of postoperative adjuvant therapy in preventing treatment failure after primary treatment with surgery in early invasive cervical cancer patients associated with the following histopathologic high-risk factors: lymph node metastasis (either macroscopic or microscopic), parametrial extension, lymphovascular permeation and depth of invasion > or =10 mm. Postoperative adjuvant concurrent chemoradiotherapy (PCCRT), postoperative adjuvant chemotherapy (PCT), or postoperative adjuvant radiotherapy (PRT) alone was administered to the 80 early invasive cervical cancers with at least one of the high-risk factors. Each of 61 patients received three to six cycles of chemotherapy at intervals of approximately 3 weeks. Twenty three patients were treated with PCCRT, 38 patients were treated with PCT alone, and 19 patients received PRT. The 5-year survival rates of patients with macroscopic lymph node metastasis were 66.7% and 35.7% in PCCRT and PRT, respectively. With microscopic lymph node metastasis, the 5-year survival rates were 83.3%, 60.0%, and 70.1% in PCCRT, PCT, and PRT, respectively. With parametrial extension, the 5-year survival rate was 58.1% in PCCRT. The 5-year survival rates of patients with lymphovascular permeation were 100%, 90.9%, and 66.7% in PCCRT, PCT, and PRT, respectively. With depth of invasion > or =10 mm, the 5-year survival rates were 100% and 91.3%, in PCCRT and PCT, respectively. PCCRT appears to be superior to PRT or PCT alone in early invasive cervical cancer patients with histopathologic high-risk factors.

Adenocarcinoma↗