Biomedical subjects

K Seo

Publications and source records attributed to K Seo.

At least 19 recordsLinked to original sources

PubMed2005

Comparative study on calretinin immunoreactivity in gerbil and rat retina.

Expression of calretinin in retina has been ascribed to multiple biological and functional aspects in the visual system. In this study, we examined the distribution patterns of calretinin immunoreactivity in gerbil and rat retina. In the gerbil, calretinin immunoreactivity was present in bipolar and amacrine cells of the inner nuclear layer and in neurones of the ganglion cell layer. In the rat, amacrine and ganglion cells showed calretinin immunoreactivity, but bipolar cells did not contain calretinin immunoreactivity. In both species, calretinin immunoreactivity was absent in cones, cone bipolars, and horizontal cells. In conclusion, gerbil as well as rat has a rod-dominant retina. The differences in calretinin expression between rat and gerbil require further investigations under various functional and developmental conditions.

Animals↗

PubMed2005

Histochemical and electron microscopic study on motor neurone degeneration following transient spinal cord ischaemia at normothermic conditions in rabbits.

This study was carried out to investigate the motor neurone degeneration in the ventral horn following transient spinal cord ischaemia at normothermic conditions in rabbits. Transient spinal cord ischaemia was induced by occlusion of the abdominal aorta underneath the left renal artery for 15 min at normothermia (38.7 degrees C). Sections at the level of L7 were examined using histochemical and electron microscopic methods. Cresyl violet-positive motor neurones began to reduce in number at 3 h after ischaemia reperfusion, and were not detectable at 48 h after ischaemia reperfusion. Acid fuchsin-positive motor neurones were detected at 1 h after ischaemia reperfusion, significantly increased up to 6 h after the ischaemia reperfusion, and eventually disappeared by 48 h after ischaemia reperfusion. In electron microscopic findings, the disintegration of cytoplasmic membranes, and the disruption of mitochondria and endoplasmic reticulum were observed in motor neurones at 30 min after ischaemia reperfusion. Motor neurones showed necrotic findings with pyknotic degeneration at 1 h after ischaemia reperfusion. The necrotic degeneration became severer time dependently after ischaemia reperfusion. At 48 h after ischaemia reperfusion, cellular components were not detectable in motor neurones. In conclusion, we suggest that the degeneration pattern of motor neurones of the ischaemic spinal cord was necrotic after ischaemia reperfusion under normothermic conditions.

Animals↗

PubMed2004

Characteristics of a newly developed dentomaxillofacial X-ray cone beam CT scanner (CB MercuRay): system configuration and physical properties.

OBJECTIVE: The purpose of this paper is to present the system configuration and physical properties of a new dentomaxillofacial X-ray cone beam CT system (CB MercuRay) being developed. METHODS: The system consists of an image intensifier and a cone beam X-ray source. There are two different models of this system, each with a different size image intensifier, 9" or 12". Each system has three field of view (FOV) modes. The 12" system has facial (F), panoramic (P) and implant (I) FOV modes. The 9" system has P, I and dental (D) modes. Images produced by these systems consist of 512 x 512 x 512 isotropic voxels. Physical properties such as resolution, noise and distortion of the images were evaluated in this study. Modulation transfer function (MTF) was measured using Boone's method. Image noise was measured as the standard deviation of the CT value in water. Circularity of the axial images yielded by the two models was measured using an 8 mm diameter acrylic pipe phantom. RESULTS: The resolving power at a MTF of 0.1 in the D mode was over 2.0 lp mm(-1), suggesting that this system yields images of high resolution. The standard deviation of the CT value in water was approximately 80, which is thought to be greater than that of conventional CT. The circularity of images of the pipe phantom was 99% of the ideal value. CONCLUSION: This study shows that our newly developed cone beam CT system produces high resolution three-dimensional volumetric images that will be useful for the examination of dentomaxillofacial disorders.

Adult↗

PubMed2003

Development of dento-maxillofacial cone beam X-ray computed tomography system.

We have developed a cone beam X-ray computed tomography (CT) system to make more accurate three-dimensional (3-D) images for diagnosis of dento-maxillofacial region. The developed system has sufficient spatial resolution, resolution of 3-D images and image distortion for diagnosis of dentomaxillofacial region.

Humans↗

PubMed2002

[A case report of ross operation and ventricular septal defect closure following correction of type A interruption by modified Blalock-Park, pulmonary artery banding and patent ductus arteriosus division].

A 2-year-old boy who had undergone a correction of a type A interruption using a modified Blalock-Park operation, pulmonary artery banding and the division of a patent ductus arteriosus, underwent a Ross operation and closure of ventricular septal defect (VSD). Although a pre-operative echo cardiogram revealed a bicuspid aortic valve, and a Doppler echocardiogram showed only 10 mmHg of pressure gradient across the aortic valve, Ross procedure was performed as a procedure accompanying the closure of a total conus VSD. The total conus VSD was closed with a Dacron patch using pledget mattress sutures. In addition, a running suture was applied over the denuded aortic root and the cranial margin to achieve water tight closure. An aortic root replacement procedure was our first choice for the Ross operation. After both coronary buttons were re-implanted into pulmonary sinuses, a pulmonary artery autograft was wrapped around by the remaining aortic wall for reinforcement to prevent future dilatation. The main pulmonary artery was reconstructed using a bicuspid pericardial valve conduit with a diameter of 24 mm. A post-operative echocardiogram showed no neoaortic valve regurgitation, good coaptation of tri-leaflets, mild regurgitation of pericardial valve and good cardiac performance.

Abnormalities, Multiple↗

PubMed2002

[A modified Fontan operation in the presence of a supracardiac total anomalous pulmonary venous connection].

We report a case of 2-year-old girl with asplenia syndrome who successfully underwent modified Fontan procedure and concomitant repair of supracardiac total anomalous pulmonary venous connection (TAPVC). The preoperative diagnosis included a common atrioventricular canal (type C), a double outlet right ventricle, a common atrium, common atrioventricular valve regurgitation, pulmonary stenosis, and a bilateral superior vena cava (SVC). Cardiac catheterization revealed a Qp/Qs of 1.3, mean PA pressure of 16 mmHg and an Rp of 1.3. The TAPVC drained to left SVC (LSVC) at a position proximal to the hemiazygos vein with an ostium of 5 mm in diameter. The LSVC was divided distal to its connection to the common pulmonary vein (CPV). The TAPVC ostium was cut back into the CPV, then it was anastmosed with posterior aspect of the atrial wall in an effort to provide a wide anastomosis. The postoperative course was uneventful and the patient was discharged from hospital on the 35th postoperative day.

Abnormalities, Multiple↗

PubMed2002

[Extracardiac fontan procedure in adult: report of a case].

We report a case of a 28-year-old female who underwent an extracardiac Fontan procedure. The subject was diagnosed as an atrioventricular septal defect (Rastelli classification: type C), a double outlet right ventricle, pulmonary artery stenosis, a hypoplasty of left ventricle, total anomalous venous return (Darling: Ib + IIb), and atrial flutter. She underwent a Blalock shunt and an aorto-pulmonary shunt at the ages of 3 and 9 years, respectively. Under a total CPB, an extracardiac total cavo-pulmonary connection (TCPC), using a 26 mm Hemashield graft, was completed. The postoperative course was uneventful. The complicated atrial anatomy and atrial arrhythmia indicated TCPC in this adult patient.

Adult↗

PubMed2001

Optical imaging of excitation propagation evoked by stimulation to the trigeminal caudalis.

The present study reports on a characteristic spatio-temporal propagation of differential fluorescent images in the rat brain stem slice by a high-speed optical imaging technique. Coronal or sagittal slices were stained with a voltage-sensitive dye RH-414, and the superficial layer of the trigeminal caudalis (Vc) was then electrically stimulated. The marginal layer and substantia gelatinosa showed larger rostrocaudal excitation than coronal, despite a lack of tract stimulation expansion in either direction. A perfusion of 0.5 micromol/l TTX, not 10 micromol/l CNQX suppressed these propagations. These findings suggest that the superficial layer of Vc has spatial differences in neuronal excitation propagation, as evidenced by morphological observations that dendrites in the superficial layers extend in the rostrocaudal direction.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

PubMed2001

Central mu opioid receptor mechanisms modulate mustard oil-evoked jaw muscle activity.

The injection of the small-fibre excitant and inflammatory irritant mustard oil (MO) into the temporomandibular joint (TMJ) region of rats evokes a sustained and reversible increase in electromyographic (EMG) activity of jaw muscles. The 'rekindling' of this nociceptive reflex by intrathecal (i.t.) administration of the opiate antagonist naloxone and mu but not delta and kappa selective opioid antagonist, suggests that it may be modulated by endogenous opioid inhibitory mechanisms.

Animals↗

PubMed2001

Functional uncoupling of T-cell receptor engagement and Lck activation in anergic human thymic CD4+ T cells.

Human thymic CD1a-CD4+ T cells in the final stage of thymic maturation are susceptible to anergy induced by a superantigen, toxic shock syndrome toxin-1 (TSST-1). Thymic CD4+ T-cell blasts, established by stimulating human thymic CD1a-CD4+ T cells with TSST-1 in vitro, produce a low level of interleukin-2 after restimulation with TSST-1, whereas TSST-1-induced adult peripheral blood (APB) CD4+ T-cell blasts produce high levels of interleukin-2. The extent of tyrosine phosphorylation of the T-cell receptor zeta chain induced after restimulation with TSST-1 was 2-4-fold higher in APB CD4+ T-cell blasts than in thymic CD4+ T-cell blasts. The tyrosine kinase activity of Lck was low in both thymic and APB CD4+ T-cell blasts before restimulation with TSST-1. After restimulation, the Lck kinase activity increased in APB CD4+ T-cell blasts but not in thymic CD4+ T-cell blasts. Surprisingly, Lck was highly tyrosine-phosphorylated in both thymic and APB CD4+ T-cell blasts before restimulation with TSST-1. After restimulation, it was markedly dephosphorylated in APB CD4+ T-cell blasts but not in thymic CD4+ T-cell blasts. Lck from APB CD4+ T-cell blasts bound the peptide containing the phosphotyrosine at the negative regulatory site of Lck-505 indicating that the site of dephosphorylation in TSST-1-activated T-cell blasts is Tyr-505. Confocal microscopy demonstrated that colocalization of Lck and CD45 was induced after restimulation with TSST-1 in APB CD4+ T-cell blasts but not in thymic CD4+ T-cell blasts. Further, remarkable accumulation of Lck in the membrane raft was observed in restimulated APB CD4+ T-cell blasts but not in thymic CD4+ T-cell blasts. These data indicate that interaction between Lck and CD45 is suppressed physically in thymic CD4+ T-cell blasts and plays a critical role in sustaining an anergic state.

Adult↗

PubMed2001

Involvement of GABA(A) receptor in modulation of jaw muscle activity evoked by mustard oil application to the rat temporomandibular joint.

The effect of intrathecal administration of the GABA(A) receptor antagonist bicuculline methylbromide on jaw muscle electromyographic (EMG) activity evoked by mustard oil injection into the rat temporomandibular joint was studied. Bicuculline given prior to mustard oil augmented the EMG activity evoked by mustard oil, and "rekindling" of EMG activity was induced by bicuculline given 30 min after mustard oil. These results suggest that central GABA(A) receptors modulate reflex responses to noxious craniofacial stimuli.

Animals↗

PubMed2001

Effects of leucocyanidines on activities of metabolizing enzymes and antioxidant enzymes.

Procyanidolic oligomers (leucocyanidines, LCs) extracted from grape seeds (Vitis vinifera) are known to have antioxidant and antimutagenic activities, and a protective effect against cardiovascular disease. In the present study we examined the influence of LCs on the activities of phase 1 enzymes and conjugation enzymes and on antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. Administration of LCs (25, 50, and 100 mg/kg. p.o. for 7 d) markedly decreased the activities of NADPH-cytochrome P450 reductase, P4501A1, P4501A2, and P4503A4, but significantly increased the activities of glutathione S-transferase and phenolsulfotransferase in rat liver. However, the activities of antioxidant enzymes were not affected by LC administration. The inhibition of P450s and increases in phase II enzyme activities indicate a role for LCs as a chemopreventive agent against toxic or carcinogenic metabolites of P450 isozymes.

Animals↗

PubMed2001

Blind separation of cardiac components and extraction of input function from H(2)(15)O dynamic myocardial PET using independent component analysis.

UNLABELLED: The independent component analysis (ICA) method is suggested to be useful for separation of the ventricles and the myocardium and for extraction of the left ventricular input function from the dynamic H(2)(15)O myocardial PET. The ICA-generated input function was validated with the sampling method, and the myocardial blood flow (MBF) calculated with this input function was compared with the microsphere results. METHODS: We assumed that the elementary activities of the ventricular pools and the myocardium were spatially independent and that the mixture of them composed dynamic PET image frames. The independent components were estimated by recursively minimizing the mutual information (measure of dependence) between the components. The ICA-generated input functions were compared with invasively derived arterial blood samples. Moreover, the regional MBF calculated using the ICA-generated input functions and single-compartment model was correlated with the results obtained from the radiolabeled microspheres. RESULTS: The ventricles and the myocardium were successfully separated in all cases within a short computation time (<15 s). The ICA-generated input functions displayed shapes similar to those obtained by arterial sampling except that they had a smoother tail than those obtained by sampling, which meant that ICA removed the statistical noise from the time--activity curves. The ICA-generated input function showed a longer time delay of peaks than those obtained by arterial sampling. MBFs estimated using the ICA-generated input functions ranged from 1.10 to approximately 2.52 mL/min/g at rest and from 1.69 to approximately 8.00 mL/min/g after stress and correlated well with those calculated with microspheres (y = 0.45 + 0.98x; r = 0.95, P < 0.000). CONCLUSION: ICA, a rapid and reliable method for extraction of the pure physiologic components, was a valid and useful method for quantification of the regional MBF using H(2)(15)O PET.

Animals↗

PubMed2001

Double-Switch operation for congenitally corrected transposition.

Double-switch operation was performed in 76 patients with congenitally corrected transposition of the great arteries at the Heart Institute of Japan, Tokyo Women's Medical University. Detailed surgical techniques of Mustard and Senning procedures for inlet switch, as well as arterial switch operation, pulmonary reconstruction by direct right ventricular-pulmonary arterial anastomosis, and external conduit repair for outlet switch are described in detail.

Adolescent↗

PubMed2001

[Case report of CABG for progressive coronary artery stenosis after 22-year history of Kawasaki disease].

More than 30 years has passed since Kawasaki disease was recognized as an independent disease entity, but the cardiovascular complications of Kawasaki disease are still not well known. We report an 22-year-old woman who underwent triple coronary artery bypass grafting because of a coronary artery aneurysm and multiple coronary artery stenoses, 22 years after the diagnosis of Kawasaki disease. A 2 cm coronary artery aneurysm due to Kawasaki disease was diagnosed when she was 10 years old, when she first presented with the symptom of dyspnea on effort. Since then, she was followed at the outpatient clinic. When she was 19 years old, the first coronary catheterization was performed. Two years later, the second coronary catheterization revealed progression of coronary artery disease. Therefore, coronary artery bypass grafting was performed. This case is rare from the point of view of long-term progression of coronary artery disease.

Adult↗

PubMed2001

[A comparison between midline and paramedian approaches for combined spinal-epidural anesthesia].

We compared midline approach with paramedian approach for combined spinal-epidural anesthesia (CSEA) by needle through needle technique. Seventy patients undergoing elective gynecological surgery received CSEA with a 27 G Whitacre spinal needle, which protrudes 12 mm beyond the tip of the Tuohy needle. The successful subarachnoid puncture with first attempt was noted in 33 patients (94%) of midline group (M group), in 31 patients (89%) of paramedian group (P group). At the subarachnoid puncture, skin to epidural space distance (43.2 mm vs 53.4 mm) and protrusion length of spinal needle (5.5 mm vs 8 mm) were significantly longer in the P group than in the M group. Abdominal radiography revealed the flexion of epidural catheter in 19 patients (54%) of M group and in 2 patients (6%) of P group. The choice of midline or paramedian approach for CSEA did not affect the success rate of the subarachnoid puncture, but paramedian approach required longer protrusion length of the spinal needle than midline approach. To raise the success rate of subarachnoid puncture by paramedian approach, a long protruded spinal needle is recommended.

Adult↗

PubMed2001

Angiogenesis effects of nerve growth factor (NGF) on rat corneas.

This study was performed to evaluate the effects of nerve growth factor (NGF) upon angiogenesis in the rat cornea, to examine its possible application as an alternative angiogenic inducer and to provide basic data for further studies. Angiogenesis was induced by cornea micropocket assay, as previously described. Eight of thirty two eyes of Sprague-Dawley rats were randomly assigned to one of four groups, namely, a non-NGF group (Group 0), a 0.5 ng of NGF group (Group 0.5), a 1.0 ng of NGF group (Group 1.0) and a 5.0 ng of NGF group (Group 5.0). Pellets made of poly-2-hydroxylethylmethacrylate and sucralfate were implanted into the corneal stroma no closer than 1 mm from the limbus. After the implantation, the number of new vessels, vessel length and circumferential neovascularization were examined daily under the surgical microscope over a period of 7 days. The area of neovascularization was determined using a mathematical formula. Although new vessels in Group 0 and Group 0.5 were first observed at day 5, those of Groups 1.0 and 5.0 were first noted on days 4 and 3, respectively. However, the growth rates of new vessels in Groups 1.0 and 5.0 were higher than those of Groups 0 and 0.5 with the passage of time. The number, length, circumferential neovascularization and areas covered by the vessels in Groups 1.0 and 5.0 were significantly more than in Group 0 and Group 0.5 (p<0.05). This study showed that NGF had a dose-dependent angiogenic effects on the rat cornea and that the minimal effective dose of NGF was 1.0 ng per cornea. Also, it showed that NGF would be useful in angiogenic studies as an alternative angiogenic inducer.

Angiogenesis Inducing Agents↗

PubMed2000

Postnatal development of central nociceptive mechanisms modulating jaw muscle activity in the rat.

Postnatal changes in the electromyographic (EMG) activity of jaw muscles evoked by mustard oil (MO) application into the rat temporomandibular joint region and the recurrence of increased jaw muscle activities after intravenous injection of naloxone were compared among 4, 6 and 8-week-old rats. In all the groups, MO application increased EMG activity on the ipsilateral side, however, 4-week old rats showed only a small increase in EMG activity on the contralateral side. The EMG activity on the contralateral side increased in an age-dependent manner. The recurrence of increased jaw muscle activity was not induced in 4-week old rats. These results suggest that a neural circuit for generating contralateral responses and mechanisms for central excitation are not established until after 4 weeks postnatally.

Aging↗