• The Korean Journal of Pharmacology
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• v.32 no.3
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• pp.323-334
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• 1996

Male Mongolian gerbils $(60{\sim}80g)$ were given DL-difluoromethylornithine (DFMO; 250mg/kg, ip) and methylglyoxal bis(guanylhydrazone) (MGBG; 50 mg/k, ip), respectively, 1 h prior to transient (7 min) occlusion of bilateral common carotid arteries (OBC7) and a daily dose of one of them for 6 days after recirculation, and the polyamine contents, activities of ornithine and S-adenosylmethionine decarboxylases (ODC and SAM-DC), and light microscopic findings of the hippocampus were evaluated. The hippocampal putrescine (PT) levels of the control gerbils treated with saline (STGr), markedly increased after OBC7, showing a peak level at 24 h after recirculation. The peak PT level was reduced in DFMO treated gerbils (DTCr) and in MGBG treated gerbils (MTGr). And 7 days after recirculation, the PT level of DTGr was decreased to about 75% of the PT level in the sham operated group (nonTGr) and to about 55% of the STGr level, respectively. The hippocampal spermidine (SD) level of STGr tended to decline, showing the lowest value at 8 h after recirculation. But the spermidine (SD) level of DTGr was somewhat higher at 8 h after OBC7 than those of STGr and MTGr The hippocampal spermine (SM) levels of all the experimental groups were little changed for 7 days after OBC. OBC7 markedly increased the hippocampal ODC activity. reaching a maximum (about 3 times higher than preischemic level) at 8 h and rapidly recovered to the control value by 24 h in STGr gerbils, and the OBC7-induced increase of ODC activity was significantly attenuated by DFMO or MGBG treatment. Whereas OBC7 induced a rapid decrease of the hippocampal SAMDC activity follwed by gradual recovery to the preischemic level, and the decrease of the SAMDC activity was slightly attenuated by DFMO or MGBG treatment. 7 Days after OBC7 the histological finding of the hippocampal complex stained with cresyl violet showed an extensive delayed neuronal damage in the CA1 region and to a lesser extent, in the dentate gyrus, sparing the CA3 region. And the neuronal death was aggevated by DFMO but significantly attenuated by MGBG. The immunochemical reactivity of hippocampus to anti-GFAP antibody was significantly increased in the CA1 region and to a lesser extent, in the dentate gyrus 7 days after OBC7, but was little changed in the CA3. And the increase of the anti-GFAP immunoreactivity was moderately enhanced by DFMO and significantly suppressed by MGBG. These results suggest that the polyamine metabolism may play a modulatory role in the ischemic brain damage.

• Investigative Magnetic Resonance Imaging
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• v.3 no.2
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• pp.173-178
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• 1999

Purpose : To evaluate the usefulness of functional MRI (fMRI) of visual cortex in patients with ischemic infarction in the occipital lobe. Materials and Methods : Four patients with the symptoms and signs of visual cortical ischemia were included. Functional MRI was performed by 2D-FLASH technique with the parameter of 90/56msec TR/TE, $40^{\circ}$ flip angle, $240{\times}240{\;}FOV,{\;}64{\times}128$ matrix number, 8.32 seconds acquisition time, 8mm slice thickness. An axial slice including both visual cortices was selected and alternative activation and resting of the visual cortex was performed using red color photostimulator. all patients undertook visual field test, and vascular abnormality was examined by MRA (n=4) and DSA (n=2). fMRI results were compared with the results of a visual field test, conventional MRI and cerebral angiography. Results : On fMRI, decreased activity of the visual cortex was found in the occipital lobe corresponding to stenosis of the posterior cerebral artery or its branch noted on angiogram. However, 2 of 4 patients showed no abnormal findings on conventional MRI. Visual field defect was noted in 3 patients, one and of whom showed no abnormality on conventional MRI and diffusion-weighted image, but revealed decreased activity in the corresponding visual cortex on fMRI. Conclusion : fMRI may be a sensitive method for detection of the status of decreased blood flow or vascular reserve which other methods can not.

• Clinical and Experimental Pediatrics
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• v.49 no.11
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• pp.1158-1166
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• 2006

Purpose : The purpose of this study is to make a diagnostic classification and discuss a diagnostic strategy of floppy infants by investigating clinical, neurological, electrophysiological, and genetic analysis of infants admitted to intensive care units with the complaint of hypotonia. Methods : A retrospective study was performed from Jan. 1993 to Dec. 2005 in neonatal and pediatric intensive care units of Seoul National University Children's Hospital. Clinical features and all tests related to hypotonia were investigated. Results : There were 21 cases of floppy infants admitted to intensive care units. Final diagnosis was classified as centra (7 cases[33.3 percent]), peripheral (11 cases [52.4 percent]), and unspecified (3 cases [14.3 percent]). Among the central group, three patients were diagnosed as hypoxic ischemic encephalopathy, two patients as Prader-Willi syndrome, one patient as chromosomal disorder, and one patient as transient hypotonia. Among the peripheral group, four patients were diagnosed as myotubular myopathy, three patients as SMA type 1, two patients as congenital myotonic dystrophy, one patient as congenital muscular dystrophy, and one as unspecified motor-neuron disease. Motor power was above grade 3 on average, and deep tendon reflex was brisk in the central group. Among investigations, electromyography showed 66 percent sensitivity in the peripheral group, and muscle biopsy was all diagnostic in the peripheral group. Brain image was diagnostic in the central group, and Prader-Willi FISH or karyotyping was helpful in diagnosis in central group. Morbidity and mortality was more severe in the peripheral group Conclusion : Classification of diagnosis by clinical characteristics in this study, and application of investigations step by step, may provide an effective diagnostic strategy.

• Journal of Chest Surgery
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• v.42 no.4
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• pp.441-446
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• 2009

Background: Side clamping of ascending aorta during proximal graft anastomosis in coronary bypassing surgery in-creases the risk of direct aortic injury as well as embolization of intimal atheroma. Heartstring proximal sealing system (Guidant Corporation, Santa Clara, Calif), developed to avoid aortic side clamping, may minimize risks of such complications. The aim of the current study is to compare the surgical outcomes of the two proximal anastomosis techniquesi.e., Heartstring system versus aortic side clamping in off pump coronary bypassing' surgery (OPCAB). Material and Method: From January 2003 to August 2008, 499 patients underwent OPCAB. Of them, proximal graft anastomosis was performed using Heartstring system in 182 patients (Group I) and conventional manual anastomosis in 317 patients (Group II). The two groups were compared for postoperative major complications and mortality. Result: Two groups showed similar characteristics in terms of preoperative demographic data, left ventricular ejection fraction, renal function and history of diabetes, hypertension and smoking. Although there was no inter-group difference in the history of cerebral ischemia (p=0.48), preoperative brain magnetic resonance angiography revealed greater incidence of severe carotid artery stenosis (>75% of lumen) in the Group I than in the. Group II (44.5% in the Group I and 30.0% in the Group II, p=0.003). There were no inter-group differences in postoperative mortality (p=0.40) and complications (p=0.47) including neurologic events (3 in the Group land 2 in the Group II, p=0.258). Whereas neurologic events all comprised transient ischemic attacks in the Group I, they comprised multiple embolic strokes in the Group II. One patient in the Group II experienced aortic dissection during proximal anastomosis which resulted in ascending aortic replacement. Conclusion: Although proximal anastomosis using Heartstring system did not show statistically significant benefit over aortic side clamping, the. absence of embolic stroke maybe a definite benefit which may be better defined through further studies over a larger cohort.

• Tuberculosis and Respiratory Diseases
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• v.47 no.5
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• pp.650-659
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• 1999

Background/Aims: It is well recognized that all aerobic cells have the protective mechanisms in order to minimize the tissue damage induced by various reactive oxygen species(ROS). Thioredoxin peroxidase(TPX) which has been recently identified and characterized functions to convert peroxide to water. The protein is also found in various subtypes(TPX-A & B, MER5, HS22 and HORF-06) and is known to be ubiquitous in most human cells. Especially, ischemic brain injuries, partial hepatectomy and radiation induced DNA damages. In treating lung cancer, radiation therapy has a major place in the local control and the relief of symptoms, but radiation induced free radical injury and resulting pulmonary fibrosis has been the major drawback of the therapy. However, little is known about the protective mechanisms and biologic modulations against radiation-induced tissue damages. Methods: Eighteen mice were divided into six groups, 3 in each group, and fifteen had received 900cGy of radiation. The mice were sacrificed according to the pre determined time schedule; immediate, 1, 2, 3 and 6 weeks after irradiation. Extracts were made from the lungs of each mice, Western blot analysis of various subtypes of TPX were done after SDS-P AGE. Examination of H & E stained slides from the same irradiated specimens and the control specimens were also performed. Results: No difference in the intensity of the immunoreactive bands in the irradiated lung samples of the mice compared to the unirradiated control was observed regardless of the time intervals, although H & E examination of the sample specimens demonstrated progressive fibrotic changes of the irradiated lung samples. Conclusion: In conclusion, according to our data, it is suggested that various thioredoxin peroxidase subtypes and catalase which are known to be increased in many repair processes may not be involved in the repair of the radiation injury to the lung and subsequent fibrosis.

• Journal of Korean Neurosurgical Society
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• v.29 no.12
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• pp.1555-1562
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• 2000

Objects : Surgical management of the distal anterior cerebral artery(DACA) aneurysms presents several unique problems to surgeons, such as difficulty in early identification of parent arteries, high incidence of rebleeding and premature rupture, and requirement of unfamiliar approach other than conventional frontotemporal craniotomy. Therefore, preoperative anatomical knowledge of anterior interhemispheric fissure and entry point of dissection is prerequisite. Authors utilized a frontobasal approach for DACA aneurysms by using consistent external landmark for guidance to the deep structure. Materials and Methods : From Nov. 1995 to Jun. 1999, a surgical clipping of DACA aneurysms was carried out in 9 patients among a total 131 patients with intracranial aneurysms. In each case, the clinical and aneurysmal features were carefully reviewed through the angiograms, medical records, and intraoperative findings. Results : The incidence of DACA aneurysms was 6.9% from our series. All cases were arisen from juxtacallosal por-tion ; 6 cases from pericallosal-callosomarginal(PC-CM) junction and 3 from pericallosal-frontopolar(PC-FP) junction. Associated vascular anomalies were noted in 3 cases and multiple aneurysms in 3 cases, respectively. The preoperative clinical grades were generally poor. An early surgery was performed in 7 cases and frontobasal interhemispheric approaches in 7 cases. Postoperatively, two patients died of complications ; one delayed ischemic vasospasm and one aspiration pneumonia but remaining patients recovered well. Conclusion : The frontobasal interhemispheric approach was useful for DACA aneurysms in early surgery. Division of superior sagittal sinus(SSS) enabled a minimal retraction of brain on both sides, and prevention of intraoperative rupture was possible. Authors suggest the frontopolar(first frontal bridging) vein as a constant external landmark for approaching the genu of the corpus callosum and juxtacallosal DACA aneurysms.

• The Korean Journal of Nuclear Medicine
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• v.29 no.3
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• pp.294-306
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• 1995

There has recently been increasing interest in the use of NMDA receptor antagonists as potential neuroprotective agents for the treatment of ischemic stroke. To evaluate the neuroprotective effect of the selective non-competitive NMDA receptor antagonist MK-801 in focal cerebral ischemia, local cerebral glucose utilization (ICGU) was examined in 15 neuroanatomically discrete regions of the conscious rat brain using the 2-deoxy-D[$^{14}C$] glucose quantitative autoradiographic technique 24 hr after left middle cerebral artery occlusion (MCAO). Animals received MK-801 (5 mg/kg i.v.) or saline vehicle before (20-30 min) or after (30 min) MCAO. Both pretreatment and posttreatment of MK-801 increased occluded/non-occluded ICGU ratio in 7 and 5 of the 15 regions measured, respectively (most notably in cortical structures). Following MK-801 pretreatment, there was evidence of widespread increases in ICGU not only in the non-occluded hemisphere (12 of the 15 areas studied) but also in the occluded hemisphere (13 of the 15 areas studied), while MK-801 postreatment did not significantly increase ICGU both in the normal and occluded hemispheres. These data indicate that MK-801 has a neuroprotective effect in focal cerebral ischemia and demonstrate that MK-801 provides widespread alterations of glucose utilization in conscious animals.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.790-798
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• 1999

Background: As the early outcome after coronary artery bypass grafting(CABG) has been stabilized, neurologic complication has now become one of the most important morbidity. The aim of this study was to find out the risk factors associated with the neurologic complications after CABG. Material and Method: In 351 patients who underwent CABG, the incidence and features of neurologic complications, with associated perioperative risk factors, were retrospectively reviewed. Neurologic complication was defined as a new cerebral infarction confirmed by postoperative neurologic examination and radiologic studies, or delayed recovery of consciousness and orientation for more than 24 hours after the operation. Result: Neurologic complications occurred in 18 patients(5.1%), of these nine(2.6%) were diagnosed as having new cerebral infarctions(stroke). Stroke was manifested as motor paralysis in four patients, mental retardation or orientation abnormality in four, and brain death in one. Statistical analysis revealed the following variables as significant risk factors for neurologic complications by both univariate and multivariate analyses: cardiopulmonary bypass longer than 180 minutes, atheroma of the ascending aorta, carotid artery stenosis detected by Duplex sonography, and past history of cerebrovascular accident or transient ischemic attack. Age over 65 years, aortic calcification detected by simple X-ray, and intraoperative myocardial infarction were significant risk factors by univariate analysis only. Neither the severity of carotid artery stenosis nor technical modifications such as cannulation of the aortic arch or single clamp technique, which were expected to affect the inciden e of neurologic complications, had significant relationship with the incidence. Conclusion: This study confirmed the strong association between neurologic complications after CABG and atherosclerosis of the arterial system. Therefore, to minimize the incidence of neurologic complications, systematic evaluation focused on atherosclerotic lesions of the arterial system followed by adequate alteration of operative strategy is needed.