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Biomedical subjects

B I Lee

Publications and source records attributed to B I Lee.

At least 55 records · Page 3Linked to original sources
PubMed1997

Bacterial expression and characterization of human pancreatic phospholipase A2.

Mammalian pancreatic phospholipases A2 (PLA2) have recently been implicated in cell surface receptor-mediated inflammation. As a first step toward understanding how human pancreatic PLA2 (hp-PLA2) interacts with membranes and other biological targets including cell-surface receptors, we constructed its bacterial expression vector which can be used for the mutagenesis and protein over-expression. The expression vector (pSH-hp) was constructed using a synthetic hp-PLA2 gene whose transcription is controlled by T7 promoter. hp-PLA2 was expressed as a mature protein in high concentration in Escherichia coli cells and formed inclusion body. The solubilization of inclusion body protein followed by the refolding and purification produced ca. 5 mg of pure protein from one liter of growth medium. Kinetic studies of recombinant human, bovine and porcine pancreatic PLA2s using polymerized mixed liposomes and micelles as substrates showed that despite their highly homologous structures these mammalian pancreatic PLA2s have distinct phospholipid head group specificity and different activity toward various lipid substrates.

Amino Acid Sequence↗
PubMed1997

Single photon emission computed tomography-EEG relations in temporal lobe epilepsy.

The role of single photon emission computed tomography (SPECT) as an independent confirmation test in presurgical evaluation of medically intractable temporal lobe epilepsy has not been critically investigated. Because spreading ictal discharges may cause a concomitant increase of cerebral blood flow in remote cerebral regions, a careful analysis of peri-injection EEG patterns and their relation to ictal SPECT may be important in evaluating the reliability of ictal SPECT. Both interictal and ictal EEG and SPECT were reviewed in 19 patients with temporal lobe epilepsy who achieved a successful seizure outcome after surgery. Patients were divided into unitemporal and bitemporal groups according to the lateralization of interictal epileptiform discharges (IED). Ictal EEG features were classified into lateralized and nonlateralized groups. The concordance between SPECT and EEG lateralizations was examined in each patient and correlated to the documented epileptogenic temporal lobe. Interictal SPECT correctly lateralized in eight of nine patients with unitemporal IED and in five of 10 patients with bitemporal IED. Ictal SPECT was highly concordant with the peri-injection ictal EEG but correctly lateralized the epileptogenic region in only 11 of 19 patients. When both pre- and postinjection EEG epochs lateralized ipsilaterally, all ictal SPECT images showed concordant lateralization. If pre- and postinjection EEG epochs were either different in lateralization or nonlateralization, ictal SPECT images often showed complex patterns of cerebral perfusion with a high incidence of false lateralization. Interictal SPECT was more sensitive and reliable in patients with unitemporal IED than in patients with bitemporal IEDs. Ictal SPECT was closely related with peri-injection EEG epochs but with frequent false lateralization. The role of ictal SPECT as an independent confirmation test in presurgical evaluation should be reappraised.

Adolescent↗
PubMed1997

Acute myopathy induced by colchicine in a cyclosporine-treated renal transplant recipient--a case report and review of the literature.

We report a case of colchicine-induced myopathy related to short-term, customary administration of colchicine. A 49-year-old male was admitted because of muscle weakness and myalgia that had developed 10 days previously. He had received renal transplantation 5 years previously and took cyclosporine as an immunosuppressant. Two weeks before admission, gout was developed and he took colchicine (1.2 mg b.i.d) by himself for three days. Colchicine-induced myopathy was clinically suspected, and colchicine intake was stopped immediately. After that, clinical symptoms gradually improved and serum muscle enzyme returned to normal. In this case, mild renal dysfunction and drug interaction between cyclosporine and colchicine wee suggested to be the precipitating factors of colchicine-induced myopathy.

Colchicine↗
PubMed1997

Experiences of epilepsy surgery in intractable seizures with past history of CNS infection.

We studied the clinical characteristics, location of epileptogenic regions, and the surgical outcomes in 18 patients with intractable epilepsy associated with previous CNS infections. All patients underwent an extensive presurgical evaluation and 11 patients had intracranial EEG monitoring. On the basis of presurgical evaluation, epileptic regions were localized to the mesial temporal (n = 12) and the neocortical (n = 6) regions. The age of the time of CNS infection was significantly younger and the latent period of non-febrile seizures after CNS infection was longer in patients with mesial temporal lobe epilepsy (MTLE). MRI showed hippocampal atrophy and hippocampal signal changes in 11 of 12 patients with MTLE. Among 6 patients with neocortical epilepsy (NE) 5 patients had normal MRI and one showed cerebral hemi-atrophy. Surgery was successful (class I & II) in all patients with MTLE, however, in the patients with neocortical epilepsy, seizure-free results were not achieved in any patients after resective surgery (6 patients) and only 2 patients achieved Class II outcomes after a second epilepsy surgery consisting of neocortical resection. Patients with MTLE after CNS infection were differentiated from the group of neocortical epilepsy by an earlier onset of CNS infection, a prolonged latent period and a higher frequency of meningitis. The characteristic pathology in this group was hippocampal sclerosis and the surgical result was excellent. Neocortical epilepsy following CNS infection usually had no focal lesion on MRI and was associated with a relatively poor surgical result. This study suggested that the surgical outcome was influenced by the type of epileptic syndromes rather than the etiology of seizures. The association of MTLE with the younger age of CNS infections and with meningitis more frequently suggested that the neocortical neurons during infancy or early childhood may be more resistant to the epileptogenesis, or that the CNS infections in patients with MTLE might be milder in severity to cause selective injuries to the hippocampal neurons during their vulnerable stage.

Adolescent↗
PubMed1996

Roles of surface hydrophobic residues in the interfacial catalysis of bovine pancreatic phospholipase A2.

The interfacial binding is a unique and important step in the phospholipase A2 (PLA2) catalyzed hydrolysis of phospholipids which is distinct from the binding of a substrate to the active site. To assess the roles of surface hydrophobic residues of PLA2 in these processes, we selectively mutated Leu-19 and Leu-20 of bovine pancreatic PLA2 to charged (L19K and L20K), uncharged polar (L19S and L20S), and amphiphilic (L19W and L20W) groups and measured their kinetic and binding properties using various phospholipid aggregates, including micelles, monolayers, and polymerized mixed liposomes. The mutations of Leu-19 and Leu-20 did not significantly change either the tertiary structure or the thermodynamic stability of bovine pancreatic PLA2. Toward monomeric 1,2-dihexanoyl-sn-glycero-3-phosphocholine, all Leu-20 mutants (L20S, L20W, and L20K) showed activities comparable to that of wild type whereas the substitution of Leu-19 with less hydrophobic side chains (L19S and L19K) reduced the activity to 70% and 50%. Toward zwitterionic 1,2-dioctanoyl-sn-glycero-3-phosphocholine (diC8PC) micelles, L20S and L20K mutants showed only 30% and 35% of the wild-type activity, respectively, whereas L20W was about twice as active as wild type. Also, L19S and L19K showed 75% and 15% of the wild-type activity, respectively. Toward anionic Trition X-100/sodium deoxycholate/diC8PC (4:2:1) mixed micelles, L20W and L20K were 2.6 times and twice more active than wild type. To determine the sn-2 acyl group selectivity of wild type and mutants, polymerized mixed liposomes were used which contained 1,2-bis[12-(lipoyloxy)-dodecanoyl]-sn-glycero-3-phosphoglycerol and 1 mol % of either 1-2[12-(1-pyrenebutanoyloxy)dodecanoyl]-2-hexanoyl-sn-glycero-3-++ +phosphocholine or 1-[12-(1-pyrenebutanoyloxy)dodecanoyl]-2-dodecanoyl-sn-glycero-3-+ ++phosphocholine. These measurements showed that Leu-19 was involved in the substrate binding and the sn-2 acyl group selectivity of bovine pancreatic PLA2 and that Leu-20 made a direct contact with the surface of phospholipid aggregates. The binding affinities of mutants to micelles, polymerized liposomes, and monolayers were well consistent with their kinetic behaviors, supporting the notion that the altered activities of Leu-19 mutants and Leu-20 mutants were due to the change in their substrate binding and interfacial binding, respectively. Finally, the L20W mutant represents the first example of protein engineering of PLA2 which results in a significant increase in interfacial binding to densely packed neutral monolayers and bilayers.

Amino Acid Sequence↗
PubMed1996

Increased contralateral cerebellar uptake of technetium-99m-HMPAO on ictal brain SPECT.

UNLABELLED: Crossed cerebellar diaschisis (CCD) is a well-known brain SPECT finding in stroke patients. Two reports, however, have described supratentorial and contralateral cerebellar hyperperfusion (crossed cerebellar hyperperfusion) on ictal brain SPECT in epileptic patients. The purpose of this study was to assess the usefulness of crossed cerebellar hyperperfusion (CCH) for the detection of epileptic foci on ictal scan. METHODS: Twelve patients with complex partial seizures having characteristic clinical, electroencephalographic (EEG) and brain SPECT findings were included. Fifteen to 20 mCi 99mTc-HMPAO were injected intravenously during the seizure period or the aura for the ictal SPECT study. The SPECT findings were visually assessed to determine whether the finding of CCH was valuable in the localization of ictal foci. RESULTS: Epileptic foci were found in the right temporal (n = 6), left temporal (n = 4), right occipital (n = 1) and left frontal (n = 1) areas. CCH was observed in 8 (75%) of the 12 patients. In two patients, contralateral cerebellar uptake was more obvious than that in the epileptic foci. In the interictal scans, cerebellar activity, which was increased in ictal period, was equalized in seven of eight patients, while perfusion was diminished in the remaining patient. CONCLUSION: CCH is a frequent finding of ictal brain SPECT and may aid in the lateralization of epileptic foci.

Adolescent↗
PubMed1995

Intrathecal synthesis of immunoglobulin G and Mycobacterium tuberculosis-specific humoral immune response in tuberculous meningitis.

Local synthesis of immunoglobulin G (IgG) in the central nervous system was investigated in 10 patients with tuberculous meningitis (TBM), 15 patients with aseptic meningitis (AM), and 15 patients with pulmonary tuberculosis only (PTBO). The IgG synthesis rate for patients with TBM was 56.4 +/- 18.9 mg/day (mean +/- standard deviation), which was significantly higher than that for patients with AM (8.0 +/- 6.7 mg/day, P < 0.001) and that for patients with PTBO (7.5 +/- 4.4 mg/day, P < 0.001). Therefore, the increased IgG synthesis rate in the central nervous system provided supporting evidence for differentiating the diagnosis of TBM from that of AM (sensitivity, 100%; specificity, 83.3%). Simultaneous measurement by enzyme-linked immunosorbent assay of IgG seroreactivity to lipoarabinomannan and purified protein derivative antigens in cerebrospinal fluid (CSF) demonstrated seropositivity in all 6 patients with TBM, 4 of 15 patients with AM, and 4 of 10 patients with PBTO. All patients showing false-positive reactivity in CSF demonstrated seropositivity in sera and normal ranges for IgG synthesis rates in CSF. Also, the semiquantitive measurement of IgG antibody (Ab) titers in these patients demonstrated higher IgG Ab titers in serum than in CSF except for one patient with a highly elevated albumin quotient, suggesting a leaky blood-brain barrier. The results strongly suggested that the Mycobacterium tuberculosis-specific IgG Abs were diffusible through the blood-brain barrier, which addresses the pitfall of serological tests for the early diagnosis of TBM. The serological detection of IgG Abs to lipoarabinomannan and purified protein derivative antigens in CSF could be misleading in the presence of simultaneously elevated of IgG Abs in serum.

Antibodies, Bacterial↗
PubMed1994

Intra-carotid thrombolytic therapy in acute ischemic stroke of carotid arterial territory.

Intra-carotid urokinase (UK) infusion in 20 patients with acute internal carotid artery (ICA) territorial ischemic stroke achieved immediate recanalization in 45% and the clinical outcome in patients with recanalization was superior to that of patients without recanalization. The procedure was most effective in patients with smaller arterial occlusions: 7 of 10 patients with MCA branch occlusions (M2 to M4) achieved recanalization compared to only 2 of 10 with distal ICA or M1 occlusions, which should be an important issue for the critical evaluation of the efficacy of thrombolytic therapy (TT). Hemorrhagic transformation was observed in 9 patients on CT scan; petechial hemorrhage in 5 and intraparenchymal hematoma formation in 4. Among 4 patients with hematoma formation, clinical deterioration was seen in 3 cases and the angiography at the immediate end of the UK infusion showed recanalization in only one patient. The average dose of UK in patients with parenchymal hematoma formation was higher than that of patients without hemorrhagic transformation (123.3 x 10(4) units vs 101 x 10(4) units). The administration of a large dose of UK, probably more than 100 x 10(4) units, and the absence of immediate recanalization seemed to increase the risk of parenchymal hematoma formation. Despite the effort of investigators, the in-hospital time delay for the TT was significant which was mainly related to the time consuming preparation for angiography especially during night. A more effective system for the earlier intervention of acute ischemic stroke needs to be developed.

Adult↗
PubMed1993

Diagnosis of tuberculous meningitis by detection of immunoglobulin G antibodies to purified protein derivative and lipoarabinomannan antigen in cerebrospinal fluid.

Enzyme-linked immunosorbent assay of immunoglobulin G (IgG) activity in cerebrospinal fluid (CSF) and sera was conducted prospectively in 27 patients with tuberculous meningitis (TBM) by using purified protein derivative (PPD) and lipoarabinomannan (LAM) antigens, from January 1989 to August 1990. 29 patients with aseptic meningitis and 49 patients with non-inflammatory neurological illnesses served as controls. All patients had a computed tomography (CT) scan of the head before a lumbar puncture. The IgG antibodies to the antigens were significantly elevated in TBM, and the reactivity was more frequently positive in the CSF than in the sera, suggesting a local synthesis of IgG in the central nervous system (CNS). The sensitivity and the specificity for the diagnosis of TBM were 59.2% and 93.9% for PPD antigen, and 85.2% and 95.9% for LAM antigen, respectively. Assay of IgG reactivity to LAM antigen was clinically very useful for the early diagnosis of TBM and was superior to PPD for detecting the serological evidence of TBM.

Adolescent↗
PubMed1993

Nucleotide sequence analysis of HTLV-I isolate from a Korean patient with HAM/TSP.

Limited nucleotide sequences of human T-cell lymphotropic virus type I (HTLV-1) provirus isolated from the first case of a Korean patient with HTLV-I associated myelopathy and tropical spastic paraparesis (HAM/TSP) were analysed and compared with other isolates from different regions of the world. The sequences of the env, LTR regions (536bp, 690bp respectively) showed 98.7%, 99.3% homologies with the prototype HTLV-I, ATK-1, isolated from a Japanese Adult T-cell leukemia (ATL) patient. A comparison between other isolates from different geographical origins revealed that the Korean HTLV-I isolate is more closely related to Japanese isolates than to those from other geographical origins.

Adult↗
PubMed1992

Can we predict carbamazepine responsiveness in partial epilepsy?

We studied 153 patients with partial epilepsy who were placed on a carbamazepine monotherapy plan in order to evaluate the clinical factors that may determine drug responsiveness to carbamazepine. The subjects were divided into 3 groups based on their therapeutic outcome--complete seizure control (44%), significant seizure reduction (32%) and unsatisfactory control (24%). Fifteen tentative clinical factors were examined in relation to the therapeutic outcomes. Factors such as seizure type, number of generalized tonic-clonic seizures, age of onset, duration of illness, seizure frequency, previous treatment and EEG finding were relevant to drug responsiveness. However, other variables including mental retardation, etiology, febrile convulsion, positive family history and abnormal neurologic examination showed no significant correlation. Our data suggest that a potential success of carbamazepine treatment should not be underestimated even in patients with complicated clinical features.

Adolescent↗
PubMed1991

A case of herpes zoster myelitis: positive magnetic resonance imaging finding.

A 33-year-old man developed a progressive myelopathy after a characteristic skin lesion of herpes zoster involving the right C3 and C4 dermatomes. The lesions were recognizable in the T2-weighted image of the magnetic resonance imaging (MRI) as increased signal intensities throughout the long segments of the spinal cord with maximal in the cervical portion, which was compatible with the pathological findings reported in autopsy studies.

Adult↗
PubMed1991

RETT's syndrome in Korea--report of two cases.

Rett's syndrome(RS) is a progressive neurodegenerative disorder characterized by exclusive occurrence in females, autistic behavior, dementia, gait ataxia, loss of purposeful use of the hands with stereotypic hand movement, and seizures. Initially RS was considered to be very rare; however, recent reports suggest that the prevalence is considerably higher and occurrence is world-wide. Because the pathophysiological process remains unknown, the diagnosis of RS is based mainly on its characteristic clinical features and course. We experienced two cases of RS which, to our knowledge, are the first reported in Korea. It is quite possible that many patients with RS not yet being diagnosed in Korea.

Child↗
PubMed1991

A case of HTLV-I associated myelopathy(HAM) in Korea.

We report the first Korean case of HTLV-I associated myelopathy (HAM), which was confirmed by Western blot assay of serum and cerebrospinal fluid. Interestingly, the proband's wife was a Japanese Korean who had lived in the endemic area of HAM, Kyushu. Japan, Investigations revealed significantly elevated anti HTLV-I antibody titers in the serum, but not in the CSF, suggesting that she was a carrier of HTLV-I. Considering that the patient had not had a previous blood transfusion, the most common route of HTLV-I, it is likely that the patient was infected by his wife through sexual intercourse. Although previous reports suggest that the transmission of HTLV-I is essentially from man to man or man to woman, our case suggests that woman to man transmission also occurs.

Adult↗
PubMed1990

Parameterization of contribution of sugar units to elution volumes in reverse-phase HPLC of 2-pyridylaminated oligosaccharides.

The reverse-phase high-performance liquid chromatography elution data, expressed in glucose units, of 2-pyridylaminated oligosaccharides (PA-oligosaccharides) originated from N-glycosides of glycoproteins have been analyzed with multiple regression to obtain parameters of contribution ascribable to each monosaccharide unit. For the best results, the known PA-oligosaccharides were classified into M-series (the "high mannose" type), X-series (those containing xylose), F-series (those containing L-Fuc alpha (1,6)GlcNAc-PA), and Z-series (all others). Within each series, a variable ("unit contribution") is assigned to every sugar component in the oligosaccharide, and the elution value of a given oligosaccharide was assumed to be the sum total of the unit contributions. The unit contribution obtained from such multiple regression calculations led to a set of elution values for oligosaccharides in each series, which showed very good agreement with the observed elution values. These unit contribution values are useful in predicting the elution value when the exact structure is known, and they also aid in predicting the structure from the known elution value.

Carbohydrate Sequence↗