Mun-Ho Lee

Disseminated Intravascular Coagulation in Korean Hemorrhagic Fever

To investigate the nature and role of coagulation and complement alterations in the pathogenesis of Korean hemorrhagic fever (KHF), the profiles from the early stages in 27 male patients were serially evaluated. Evidence of disseminated intravascular coagulation (DIC) was observed in 14 of the 27 patients (51.8%) sometime during the course of the disease. The earlier the coagulation tests were performed, the more frequently the evidence of DIC was found. The mean serum C3 concentration was significantly decreased during the early stages, while serum C4 concentrations revealed no significant variation. A significant decrease of the serum C3 concentration, however, was found only in the group with DIC. Korean hemorrhagic fever (KHF) is an acute, systemic disease characterized by fever, hemorrhagic manifestations, and renal failure. This disease has been known to occur from the Pacific Ocean to the Baltic Sea under various synonyms and toponyms including epidemic hemorrhagic fever, hemorrhagic nephrosonephritis and hemorrhagic fever with renal syndrome. Recent investigations demonstrated the identity of these conditions described from Korea, the Soviet Union, Japan, and China. Nephropathia epidemica of Scandinavia was also revealed to have a close serological relation to this disease, but with antigenic differences. The etiologic agent was identified in 1978 by Lee et al., who isolated a viral antigen from a field mouse, Apodemus agrarius coreae, which is the natural reservoir of this disease in Korea. The KHF or Hantaan virus has been propagated in cell cultures and observed electronmicroscopically. In thin sections, the virus was detected within the cytoplasmic granular matrices (viroplasms) of the infected cells. Virus particles were spherical and had an extremely electron-dense core. Negative-contrast staining showed that the virus had an icosahedral structure and annular surface capsomeres. The morphology and morphogenesis of the virus were similar to those of the orbiviruses. The characteristic pathologic findings observed in fatal cases of KHF are congestion and hemorrhage of the renal medulla, hemorrhage in the right atrial wall of the heart, and hemorrhage and necrosis in the anterior lobe of the pituitary gland. The microscopic characteristics of these lesions consist of hemorrhage, coagulation necrosis, and mononuclear cell infiltration. The clinical course of typical KHF may be divided into five phases, each designated for a characteristic physiologic aberration; febrile, hypotensive, oliguric, diuretic, and convalescent.(ABSTRACT TRUNCATED AT 400 WORDS)

Improving DOI information using 3-layer crystals for small animal PETs

Improving the spatial resolution without sacrificing the sensitivity is one of the most challenging goals for small animal PETs. The 3-layer configuration that we propose consists of 7 mm long LuYAP and 7 mm long LSO crystals aligned with each other, and 5 mm long LSO crystals with an offset of 1.15 mm. The LuYAP crystals are attached to Hamamatsu H7546B multi-anode PMTs, and the sensitive cells of which are aligned to match the 5 mm long LSO crystals. To estimate the improvement of the spatial resolution, we also simulated the 2-layer configuration of LSO and LuYAP, each with a 9.5 mm length. The Monte-Carlo simulation shows that the 3-layer configuration has a potential to improve the spatial resolution by about 30-40% at 40.0 mm from the central axis over the 2-layer configuration. To study the 3-layer configuration, we started to test the 2-layer and 3-layer configurations and presented preliminary test results.

Evaluation of the protective effect of verapamil on reperfusion injury by111In anticardiac myosin antibody in canine myocardial infarction

We quantitated the protective effect of verapamil on reperfusion injury in canine myocardial infarct using111In-anticardiac myosin antibody and correlated to the electronmicroscopic findings. Experimental myocardial infarction was performed by one hour occlusion of the anterior descending coronary artery and followed by reperfusion. Saline or verapamil (0.6 mg/kg/hr) was started at 40 minutes after coronary artery occlusion and continued throughout the experiment. There was an inverse exponential relationship between anticardiac myosin uptake and regional coronary blood flow in both the control (r=−0.86) and the verapamil treated (r=−0.71) groups. Less uptake of111In-anticardiac myosin antibody was observed in the verapamil treated group than in the control group of the regions where blood flow was lower than 30 % of normal. In the control group, the myocardium showed signs of the typical contraction band necrosis. In the verapamil treated group, however, the myocardium contained fewer electron dense granules and mild degree of contraction bands.

Robust extraction of input function from H/sub 2//sup 15/O dynamic myocardial positron emission tomography using independent component analysis

It is hard to extract the input function from the left ventricle on H/sub 2//sup 15/O PET image to estimate the regional myocardial blood flow (rMBF). In this study the authors applied blind source separation technique by Independent Component Analysis (ICA) to extract input function from the H/sub 2//sup 15/O dynamic myocardial PET. Dynamic PET scans were performed on 5 dogs at rest and dipyridamole-induced stress. A transverse slice containing the biggest heart was selected and masked so that only the cardiac components were included in the analysis. The authors assumed that the elementary activities corresponding to the left and right ventricular pool and myocardial tissue as independent sources since their anatomical structures are not overlapped in the space. After principal component analysis, ICA unmixing process was performed using the extended infomax learning algorithm and left ventricular input function was obtained. In all the cases, the authors could extract the input functions, which had identical shape with those obtained using the manually drawn region of interest, and the rMBFs obtained using them were correlated well (r=0.87, p=0.001). Since all the process was, moreover, automatically achieved with very short computation time, it will be useful for the quantification of the rMBF using H/sub 2//sup 15/O PET.