• Clinical and Experimental Pediatrics
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• v.52 no.10
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• pp.1127-1135
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• 2009

Purpose : To observe the abnormal white matter findings on the magnetic resonance imaging (MRI) scans of very-low- birth-weight (VLBW) infant brains at term-equivalent age and to determine the clinical risk factors for the development of periventricular leukomalacia (PVL). Methods : In all, MRI was performed in 98 VLBW infants and the white matter abnormalities were observed. Clinical risk factors for cystic and noncystic PVL were determined. Results : MRI scans of 74 infants (75.5%) showed diffuse excessive high signal intensity (DEHSI) in the periventricular white matter, 17 (17.3%) lateral ventricle dilation, 5 (5.1%) and 11 (11.2%) focal punctate lesions and cystic changes in the periventricular white matter, respectively, 9 (9.1%), germinal layer hemorrhage (GLH) or subependymal cysts 3 (3.1%) intraventricular hemorrhage (>grade 2) 2 (2.0%) posthemorrhagic hydrocephalus and 2 (2.0%) periventricular hemorrhagic infarct. Gestational age (GA), 1-minute Apgar score, Clinical Risk Index for Babies-II (CRIB-II) score, and inotrope use, and GA, CRIB-II score, postnatal steroid administration, inotrope use, and abnormal white blood cell (WBC) count at admission were related to cystic PVL and noncystic PVL development, respectively (P<0.05). However, in logistic regression analysis, CRIB-II (odds ratio, 1.63, 295% confidence interval, 1.15-2.30 P=0.006) for cystic PVL, and GA (odds ratio 0.90, 95% confidence interval, 0.82-0.99 P=0.036) for noncystic PVL were only significant independently. Conclusion : White matter abnormalities could be observed on MRI scans of the VLBW infant brains at term-equivalent age, and CRIB-II and GA were only independently significant for cystic and noncystic PVL development, respectively.

• Clinical and Experimental Pediatrics
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• v.52 no.2
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• pp.227-233
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• 2009

Purpose : Growth hormone (GH) replacement after retesting is necessary because impairment of body composition and cardiovascular health has been more severe in adult patients with persistent GH deficiency (GHD) from childhood to adulthood. This study aimed to investigate the factors for persistent GHD and define a highly probable group of persistent GHD in young adults with childhood-onset GHD. Methods : GHD was reassessed by insulin tolerance test (ITT) in 55 adult patients (39 males, 16 females) with childhood-onset GHD. Twelve patients presented with idiopathic GHD and 43 patients presented with organic GHD caused by tumors involving the hypothalamus-pituitary (H-P) region (n=33), other brain tumors (n=3), meningitis (n=3), leukemia (n=2) and others (n=2). Results : Forty-nine (89.1%) of 55 patients had persistent GHD. IGF-I was positively correlated with log of peak GH (r=0.57, P<0.001). There was no difference in the proportion of persistent GHD between idiopathic and organic GHD. The percentage of patients with persistent GHD was 40%, 80%, and 95.6% for patients with zero, one, two or more additional pituitary hormone deficiencies (PHDs), respectively (P=0.002). The probability of persistent GHD was higher in patients with diseases involving the H-P region (P=0.003). GHD persisted in 15 of 18 patients treated with cranial irradiation. Conclusion : We suggest that the probability of persistent GHD in adulthood was high in patients with 2 or more additional PHDs, and diseases involving the H-P region.

• The Korean Journal of Pharmacology
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• v.18 no.2
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• pp.103-117
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• 1982

In an effort to provide evidence as to the regulatory role of the central dopaminergic system on the renal function, the effects of centrally administered dopamine and its specific antagonist haloperidol were investigated. Haloperidol (HA) given intracerebroventricularly (i.c.v.) induced antidiuresis in doses of 15 and $50{\mu}g/kg$. With $15{\mu}g/kg$ sodium reabsorption in the tubules was increased, while with $50{\mu}g/kg$ free-water reabsorption was increased. However, a marked diuresis with increased sodium and potassium was observed with $150{\mu}g/kg$. Hemodynamic changes were not evident, indicating that the diuresis is of tubular origin. Dopamine (DA), on the other hand, produced antidiuresis when given i.c.v. in a dose-related fashion. With smaller doses of 5 and $15{\mu}g/kg$ the antidiuresis was related to increased reabsorption of sodium in the tubules, but higher doses of 50 and $150{\mu}g/kg$ the decreases in renal blood flow and glomerular filtration rate were evident in addition to the tubular action. After pretreatment with $150{\mu}g/kg$ HA, the effects of $15{\mu}g/kg$ DA was abolished, but the antidiuretic actions of 50 and $150{\mu}g/kg$ were not blocked, and the natriuretic diuretic action of HA was overcome and became inconspicuous. These observations indicate that the central dopaminergic system influences the renal function by producing antidiuresis, and HA elicits diuresis and natriuresis by competitively antagonizing DA specifically on the central dopaminegic receptors. The antidiuresis observed with smaller doses of HA can be best explained by the facts that there are more than two types of DA-receptors in the brain and that the presynaptic autoreceptors on the dopaminergic neurones which affect the dopamine release at the synapse are more sensitive than the postsynaptic receptors. Overall, these data provide an evidence indicating that the central dopaminergic system plays a role in the regulation of renal function in the rabbit.

• The Korean Journal of Pharmacology
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• v.28 no.2
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• pp.147-162
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• 1992

The objectives of the present experiments were to characterize the effects of the peptides belonging to the pancreatic polypeptide family on the contractility of cerebral arteries and to observe the interactions of these peptides with the cyclic nucleotide activators and the potassium channel openers. Dogs of either sex, $20{\sim}30\;Kg$ in weight, were sacrificed. Basilar and middle cerebral arteries from brain were isolated and prepared for myography in the PSS equilibrated with 95% $O_2$ and 5% $CO_2$ at $37^{\circ}C$. The endothelial cells of the spiral strips were removed by CHAPS solution (0.3% w/v, 15 seconds). 1. PP, PYY and NPY contracted the arterial strips concentration-dependently with a rank order of potency of PYY>NPY>PP. These peptides were 20 to 200 times more potent than norepinephrine, and only PYY showed a greater potency than 5-HT. 2. Cyclic nucleotide activators, forskolin (for cAMP) and sodium nitroprusside (for cGMP) reduced the basal tone and inhibited the PP-, PYY- and NPY- induced contractions by concentration-dependent manners. Forskolin was more potent in reducing basal tone than sodium nitroprusside. 3. Potassium channel openers, RP 49356, P 1060 and BRL 38227 reduced the basal tone concentration-dependently and tended to inhibit the PP-, PYY- and NPY- induced contractions. Notably, BRL 38227 with low concentration $(0.1\;{\mu}M)$ enhanced the contractions induced by those peptides while P 1060 inhibited the contractions concentration-dependently. 4. The combinations of the cyclic nucleotide activators and the potassium channel openers were slightly additive in reducing the basal tone. P 1060 and BRL 38227 enhanced the relaxant effect of sodium nitroprusside significantly. On the PYY-induced contration $(0.1\;{\mu}M)$, $K^+$ channel openers tended to inhibit the inhibitory actions of forskolin and sodium nitroprusside. P 1060 and BRL 38227 antagonized the inhibitory action of sodium nitroprusside significantly. The results of the present study may be summarized that in canine cerebral arteries, not only NPY but also PYY may play a role in a cerebrovascular spasm, and intracellular concentration of either cAMP or cGMP may be involved in the mechanism of vasoconstrictive actions of these peptides, which may be affected either positively or negatively by a $K^+$ channel opener.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.1
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• pp.27-33
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• 2007

Purpose: We have performed SRS (stereotactic radiosurgery) for avm (arterry vein malformation) and brain cancer. In order to verify dose and localization of SRS, dose distributions from TPS ($X-Knife^{(R)}$ 3.0, Radionics, USA) and GafChromic $EBT^{(R)}$ film in a head phantom were compared. Materials and Methods: In this study, head and neck region of conventional humanoid phantom was modified by substituting one of 2.5 cm slap with five 0.5 cm acrylic plates to stack the GafChromic $EBT^{(R)}$ film slice by slice with 5 mm intervals. Four films and five acrylic plates were cut along the contour of head phantom in axial plane. The head phantom was fixed with SRS head ring and adapted SRS localizer as same as real SRS procedure. CT images of the head phantom were acquired in 5 mm slice intervals as film interval. Five arc 6 MV photon beams using the SRS cone with 2 cm diameter were delivered 300 cGy to the target in the phantom. Ten small pieces of the film were exposed to 0, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900 cGy, respectively to calibrate the GafChromic $EBT^{(R)}$ film. The films in the phantom were digitized after 24 hours and its linearity was calibrated. The pixel values of the film were converted to the dose and compared with the dose distribution from the TPS calculation. Results: Calibration curve for the GafChromic $EBT^{(R)}$ film was linear up to 900 cGy. The R2 value was better than 0.992. Discrepancy between calculated from $X-Knife^{(R)}$ 3.0 and measured dose distributions with the film was less than 5% through all slices. Conclusion: It was possible to evaluate every slice of humanoid phantom by stacking the GafChromic EBT film which is suitable for 2 dimensional dosimetry, It was found that film dosimetry using the GafChromic $EBT^{(R)}$ film is feasible for routine dosimetric QA of stereotactic radiosurgery.

• The Korean Journal of Pharmacology
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• v.24 no.2
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• pp.165-178
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• 1988

In this study, the effect of single or repeated (daily for 7 or 14 days) electroconvulsive shock (ECS) on central and peripheral opiate system and modification of the actions of ECS by several psychoactive drugs were investigated in the rat. Repeated ECS caused increase of Met-enkephalin content and decrease of Bmax of specific $[^3H]$imorphine binding in the rat brain. These effects were persisted more than 7 days after the last ECS, but single ECS failed to show these effects. However, ${\beta}-endorphin$ content was decreased in midbrain preparation and increased in plasma by repeated or single ECS. These phenomenon was seen shortly after the last ECS. After ECS-induced seizure was prevented by phenobarbital, ECS-induced increase in Met-enkephalin content was significantly attenuated. Imipramine or pargyline did not affect the action of repeated ECS. On the other hand, reserpine, chlorpromazine or haloperidol which were classified as neuroleptic antipsychotics, augmented the ECS-induced changes of central and peripheral opiate parameters. Furthermore, in groups received repeated ECS, changes of Bmax of specific $[^3H]-morphine binding$ binding was inversely correlated with changes of Met-enkephalin contents, but not with changes of ${\beta}-endorphin$ contents. From these results, it is inferred that the central or peripheral opioidergic system may be involved in the therapeutic and/or adverse effects of ECS which also can be influenced by some psychoactive drugs.

• Journal of radiological science and technology
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• v.32 no.2
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• pp.177-182
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• 2009

Purpose : This study presents the optimization of flip angle (FA) to obtain higher contrast to noise ratio (CNR) and lower specific absorption rate (SAR). Materials and Method : T1-weighted images of the cerebrum of brain were obtained from 50$^\circ$ to 130$^\circ$ FA with 10$^\circ$ interval. Signal to noise ratios (SNRs) were calculated for white matter (WM), gray matter (GM), and background noise. The proper FA was analyzed by T-test statistics and Kruskal-wallis analysis using R1 = 1- exp ($\frac{-TR}{T1}$) and Ernst angle cos $\theta$ = exp ($\frac{-TR}{T1}$). Results : The SNR of WM at 130$^\circ$ FA is approximately 1.6 times higher than the SNR of WM at 50$^\circ$. The SNR of GM at 130$^\circ$ FA is approximately 1.9 times higher than the SNR of GM at 50$^\circ$. Although the SNRs of WM and GM showed similar trends with the change of FA values, the slowdown point of decrease after linear fitting were different. While the SNR of WM started decreasing at 120$^\circ$ FA, the SNR of GM started decreasing at less than 110$^\circ$. The highest SNRs of WM and GM were obtained at 130$^\circ$ FA. The highest CNRs, however, were obtained at 80$^\circ$ FA. Conclusion : Although SNR increased with the change of FA values from 50$^\circ$ to 130$^\circ$ at 3T SE T1WI, CNR was higher at 80$^\circ$ FA than at the usually used 90$^\circ$ FA. In addition, the SAR was decreased by using smaller FA. The CNR can be increased by using this optimized FA at 3T MR SE T1WI.

• Journal of Ginseng Research
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• v.24 no.1
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• pp.8-17
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• 2000

Estrogen can influence on the expression of behaviors not associated directly with reproduction, including learning and memory. Recently estrogen has received considerable attention for its effects on neuroprotection and neural circuits in brain areas associated with cognition. Although estrogen replacement therapy may be helpful to postmenopausal women, it also results in a number of harmful side effects. Ginseng also has steroidal qualities and contains several ginsenoside components which have similar backbone structure to estrogen. The objectives of this experiment were 1) to examine the effects of estrogen and 2) to investigate the effects of ginsenosides as estrogenic agent on learning and memory using the Morris water maze, a traditional experimental task for spatial memory. In the experiments designed here, ovariectomized mice were implanted subcutaneously with Sila, itic capsules containing 17${\beta}$-estradiol (100∼250 $\mu\textrm{g}$/$m\ell$), panaxadiol (PD) and panaxatriol (PT) saponins (15∼100 $\mu\textrm{g}$/$m\ell$) diluted with sesame oil. In the first set of experiment, the effects of estradiol on learning and memory during the Morris water maze was examined. When estradiol was delivered via Silastic capsules following training improved spatial memory performance in ovariectomized female mice. In the second set of experiment, three different PD and PT saponin concentrations were delivered via Silastic implants to ovariectomized female mice and their effects were compared with estrogenic effects. Results of three separate experiments demonstrated that estradiol, PD and PT administrated by Silastic implants for 2 weeks prior to water maze training significantly improved spatial memory performance compared to ovariectomized (OVX) mice, as indicated by lower escape latency over trial. The positive effect of estradiol suggests that estrogen can affect performance on learning and memory. In addition, the positive effect of PD and PT saponins suggest that ginsenosides have an estrogen-like effects in mediating learning and memory related behavior action.

• 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.

• Radiation Oncology Journal
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• v.14 no.2
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• pp.149-158
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• 1996

Purpose : To get an accute steepness of dose gradients at outside the target volume in intracranial lesion and a less limitation of beam selection avoiding the high dose at normal brain tissue, this Photon Knife Radiosurgery System was developed in order to provide the three-dimensional dose distribution through the reconstruction of CT scan and the combined stereotactic trans-multiarc beam mode based on linear accelerator photon beam. Materials and methods : This stereotactic radiosurgery, Photon Knife based on linear accelerator photon beam was provided the non-coplanar multiarc and trans-multiarc irradiations. The stereotactic trans-multiarc beam mode can be obtained from the patient position in decubitus. This study has provided the 3-dimensional isodose curve and anatomical structures with the surface rendering technique. The dose distribution from the combined two trans-multiarcs (2M 2TM) was compared to that of four non-coplanar multiarcs (4M) with same collimator size of 25 mm in a diameter and total gantry movements. Results : In this study, it shows that the dose distributions of stereotactic beam mode are significantly depended on the selected couch and gantry angle in same collimator size. Practical dose distribution of combined stereotactic trans-multiarc beam has shown a more small rim thickness than that of the non-coplanar multiarc beam mode in axial, sagittal and coronal plane in our study. 3-Dimensional dose line displayed with surface rendering of irregular target shape is helpful to determine the target dose and to predict the prognosis in follow-up radiosurgery. Conclusions : 3-Dimensional dose line displayed with surface rendering of irregular target shape is essential in stereotactic radiosurgery. This combined stereotactic trans-multiarc beam has shown a less limitation of the selection couch and gantry beam angles for the target surrounding critical organs. It has shown that the dose distribution of combined trans-multiarc beam greatly depended on the couch and gantry angles. In our experiments, the absorbed dose has been decreased to $27%$ / mm in maximum at the interval of $50\%$ to $80\%$ of isodose line.