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Biomedical subjects

S E Kim

Publications and source records attributed to S E Kim.

At least 55 records · Page 3Linked to original sources
PubMed1999

SPECT measurement of iodine-123-beta-CIT binding to dopamine and serotonin transporters in Parkinson's disease: correlation with symptom severity.

Iodine-123-beta-CIT (2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane) binds with high affinity to dopamine (DA) and serotonin (5-HT) transporters. This study examined the correlation of single-photon emission computed tomographic (SPECT) measures of [123I]beta-CIT binding to DA and 5-HT transporters with symptom severity in Parkinson's disease (PD). Forty-six L-dopa-responsive PD patients (Hoehn-Yahr stage 1-3) had SPECT scans at 20-24 h after injection of [123I]beta-CIT. Specific to nondisplaceable uptake ratios (designated V"3) were calculated in the striatum and hypothalamic/midbrain region, where the binding of [123I]beta-CIT is associated primarily with DA and 5-HT transporters, respectively. Striatal V"3 was significantly correlated with Hoehn-Yahr stage and total, motor and activities of daily living scores of Unified Parkinson's Disease Rating Scale (UPDRS). There was a significant correlation between the sum of lateralizing motor UPDRS subscores (tremor, rigidity, bradykinesia) calculated for each side of limbs and V"3 values in the contralateral striatum. No significant correlation was found between striatal V"3 and UPDRS rating of mentation, behavior, and mood. Hypothalamic/midbrain V"3 was not significantly correlated with either Hoehn-Yahr stage or UPDRS scores including both motor and nonmotor measures. The significant correlation of SPECT measures of striatal [123I]beta-CIT binding with motor severity suggests that [123I]beta-CIT binding to striatal DA transporters can serve as an in vivo indicator of disease severity in PD, with potential utility in the serial monitoring of disease progression.

Adult↗
PubMed1999

Occurrence of hippocampal sclerosis: is one hemisphere or gender more vulnerable?

PURPOSE: We analyzed a large group of patients investigated for suspected seizures to test whether gender or side are important factors in the origins of hippocampal sclerosis (HS). METHODS: We studied 996 consecutive patients (48% men, 52% women) by using standard hippocampal T2-relaxometry methods. RESULTS: HS was associated with a highly abnormal T2 time (< or =113 ms). Categoric analysis showed that hippocampal T2 time was independent of gender and side. T2 time was bilaterally normal in 81% of men and in 79% of women; it was unilaterally abnormal in 15% of both men and women; and bilaterally abnormal in 4% of men and in 6% of women. Highly abnormal T2 relaxometry, suggesting HS, occurred with equal frequency in men and women and on the right and left sides. Quantitative analysis of hippocampal T2 times showed values not differing significantly between men and women or between the right and left hemispheres. There was no significant interaction between gender and side. CONCLUSIONS: In patients with seizure disorders, hippocampal T2 relaxometry is not different in adult men and women and in the right and left hemispheres.

Adult↗
PubMed1999

Partial seizures manifesting as apnea only in an adult.

PURPOSE: Although several cases of apneic seizures have been reported in neonates, epileptic seizures presenting as apnea only in adults are very rare. We present a case report of a 19-year-old man with viral encephalitis and frequent episodes of apneic seizures. METHODS: Prolonged electroencephalograms (EEGs), respiratory monitorings, and imaging including ictal-interictal subtraction single photon emission computed tomography (SPECT) coregistered with magnetic resonance imaging (MRI) were performed. RESULTS: Ictal EEGs recorded during apneic episodes showed repetitive sharp waves or rhythmic theta activity arising from the left or right independent bitemporal region. Ictal SPECT was performed during one episode of apnea that showed ictal EEG discharges arising from the left posterior temporal area. Ictal-interictal subtraction SPECT coregistered with MRI revealed that the seizures originated from the left, posterior, midlateral temporal cortex. CONCLUSIONS: Previous studies with ictal EEG or brain stimulation suggest that apneic seizures might be mediated through the limbic and associated cortical systems. Our study reports on a very rare case of partial seizures with apnea only in an adult patient and is supported by ictal EEG and ictal-interictal subtraction SPECT coregistered with MRI.

Adult↗
PubMed1999

White-matter change in mesial temporal sclerosis: correlation of MRI with PET, pathology, and clinical features.

PURPOSE: To assess the magnetic resonance imaging (MRI), positron emission tomography (PET), pathology, and clinical findings of patients with the MRI feature of white-matter change (WMC) in the anterior temporal lobe. METHODS: Fifty-six patients with pathologically proven mesial temporal sclerosis were included in this study. MRI and 18F-2-deoxyglucose-(FDG) PET images were obtained before surgery in all patients. The patients were divided into two groups according to the presence of WMC on their MRI. WMC consists of an indistinct gray-white matter demarcation and an increased signal intensity of the anterior temporal lobe on T2-weighted images. The two groups were then compared in terms of MRI, PET, pathology, and clinical features. RESULTS: The MRI feature of WMC was observed in 18 (32%) of the 56 patients. PET images of those patients revealed more severe hypometabolism of the ipsilateral temporal lobes (p< 0.05). In terms of histologic findings, larger numbers of heterotopic neurons were observed in the anterior temporal lobe white matter of these patients who also shared the following clinical features: earlier seizure onset, frequent history of febrile convulsions, and favorable surgical outcomes. CONCLUSIONS: The MRI feature of WMC is an additive sign for correct seizure lateralization and may be related to a favorable surgical outcome in patients with temporal lobe epilepsy.

Adolescent↗
PubMed1999

Diffuse and focal adenomyosis: MR imaging findings.

Adenomyosis is a common gynecologic disorder that affects women during their menstrual life. Preoperative magnetic resonance (MR) images obtained in 45 patients with pathologically proved adenomyosis who underwent hysterectomy were retrospectively reviewed. Diffuse adenomyosis was seen in 30 cases (66.7%) and focal adenomyosis in 15 cases (33.3%). On T2-weighted MR images, diffuse adenomyosis usually manifested as diffuse thickening of the endometrial-myometrial junctional zone (7-37 mm; mean, 16 mm) with homogeneous low signal intensity. T2-weighted MR images were superior to contrast material-enhanced T1-weighted images in the evaluation of junctional zone thickening. High-signal-intensity foci were observed on T2-weighted images only in nine cases and on both T1- and T2-weighted images in three cases. Focal adenomyosis manifested on both T2-weighted and contrast-enhanced T1-weighted MR images as a localized, low-signal-intensity round or oval mass with a diameter of 2-7 cm (mean, 3.8 cm). All but one of the focal lesions had ill-defined margins. High-signal-intensity foci were noted in all cases of focal adenomyosis, either on T2-weighted images only (four cases) or on both T1- and T2-weighted images (11 cases). MR imaging is useful in diagnosing adenomyosis, differentiating adenomyosis from uterine myoma, and planning appropriate treatment.

Adenomyoma↗
PubMed1999

Hippocampal T(2) abnormalities correlate with antecedent events and help predict seizure intractability.

INTRODUCTION: We performed hippocampal T(2) relaxometry as part of a routine magnetic resonance imaging (MRI) examination in 50 normal controls and 127 consecutive patients referred because of suspected seizures. METHODS: On the basis of T(2) values in controls (100.2 +/- 4.2 ms) we defined normal as <110 ms ( 113 ms (>mean + 3 SD). RESULTS: After detailed investigation, 103 of these 127 patients had epilepsy and 24 did not. In the nonepilepsy group, none had abnormal hippocampal T(2) values. Twenty-seven of the 103 patients in the epilepsy group had abnormal values, 7 were borderline and 69 were normal. Only 5 patients with abnormal T(2) values did not have temporal lobe epilepsy: 1 had extratemporal lobe epilepsy, 1 had generalized epilepsy and 3 had unclassified epilepsy. Twenty-two of 27 (81%) patients with abnormal hippocampal T(2) values had intractable epilepsy [compared with 32 of 69 (46%) patients with normal values; p < 0.05, chi(2) test]. Two thirds of patients with abnormal values had a history of a major antecedent event (compared to only 7% of those with normal values, p < 0.05, chi(2) test). CONCLUSION: Abnormal T(2) relaxometry is significantly associated with intractable epilepsy as well as with major antecedent events.

Adult↗
PubMed1999

The effect of continuous ambulatory peritoneal dialysis on change in serum leptin.

OBJECTIVE: Elevated serum leptin can contribute to anorexia and poor nutrition in patients with chronic renal failure, because leptin is elevated in chronic renal failure patients with or without dialysis, especially in chronic ambulatory peritoneal dialysis (CAPD) patients. The aim of this study was to find whether leptin can be removed by peritoneal dialysis (PD) and to analyze factors that can affect serum leptin after start of CAPD by observing the change in serum leptin shortly after start of CAPD and its correlation with body mass index (BMI), with serum insulin, and with residual renal function. DESIGN: Twenty patients who started CAPD during the observation period were studied. Serum leptin was measured by radioimmunoassay before start of CAPD, 3-5 days after start of CAPD, and 1 month and 3 months after start of CAPD. Simultaneously, body weight, serum insulin, and residual renal function were measured. To compensate for the circardian rhythm of leptin, removal of leptin was assessed by measuring dialysate leptin divided by average serum leptin before and after a peritoneal equilibration test (PET). RESULTS: Leptin was eliminated by PD with a dialysate-to-serum ratio of 0.16+/-0.07, which was comparable to removal of beta2-microglobulin (0.14+/-0.06). The mean serum leptin concentrations did not decrease after 3-5 days of CAPD (8.4+/-13.1 ng/mL-->11.9+/-18.0 ng/mL) despite its removal by PD, and levels increased markedly to 189% of basal serum leptin 1 month after start of PD and to 260% of basal serum leptin 3 months after start of PD. Correlation coefficients (Spearman's rho) between change of serum leptin and change of BMI, of serum insulin, of glomerular filtration rate (average of urine creatinine clearance and urine urea clearance) were 0.267 (p > 0.05, n = 20), 0.441 (p > 0.05, n = 16), 0.706 (p > 0.05, n = 8) respectively. CONCLUSION: Leptin is removed by peritoneal dialysis. Serum leptin did not decrease in 5 days after the start of PD despite its removal by PD, but increased markedly thereafter, within 3 months after start of PD. We could not find a significant correlation between the change in leptin and the change in BMI. Factors other than fat-mass gain can stimulate leptin increase shortly after start of PD.

Adipose Tissue↗
PubMed1998

A new sesquiterpene ester from Celastrus orbiculatus reversing multidrug resistance in cancer cells.

In a search for revertants of multidrug-resistance in cancer cells, a novel (1) and two known (2,3) sesquiterpene esters were isolated from the root of Celastrus orbiculatus. The structure of 1 was elucidated as 1 beta,2 beta-diacetoxy-6 alpha,9 alpha-bis(benzoyloxy)dihydro-beta-agarofuran. Compounds 1-3 partially or completely reversed resistance to adriamycin, vinblastine, and paclitaxel of multidrug-resistant KB-V1 and MCF7/ADR cells.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Mode of action of torilin in multidrug-resistant cancer cell lines.

The mechanism of action of multidrug-resistance reversing activity of torilin was studied. In vitro experiments for the accumulation and efflux of vinblastine clearly indicated that MDR reversing effects of torilin would directly be associated with the increase of the intracellular accumulation of anticancer drugs by blocking the drug efflux. Furthermore, torilin increased the membrane ATPase activity from KB-V1 cells, suggesting that torilin might function by inhibiting drug transport mediated by P-glycoprotein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Effects of blood flow and venous network on the survival of the arterialized venous flap.

The purpose of this study was to evaluate further factors that could explain the survival mechanism in the arterialized venous flap. The authors used 16 canines to investigate the survival rate and pattern of the arterialized venous flap and compared the results with those of the conventional saphenous flap. The number and distribution of draining veins in the arterialized venous flap group were varied to observe their impact on the survival rate and pattern. Gross examination of venous network, blood gas, venogram, blood pressure, and histologic study were also carried out. Although there was no significant difference in final survival rate between conventional flap and arterialized venous flap with two efferent veins (p > 0.01), that of the arterialized venous flap increased significantly as the number of draining veins increased. Blood gas analysis showed that more effective oxygen consumption took place when the number of draining veins increased. By measuring the blood flow and volume at 8 hours after the operation with a laser Doppler flowmeter, it was possible to predict the necrosis of the arterialized venous flap. Attachment to a high pressure arterial blood flow system induced smooth muscle proliferation and neogrowth of elastic fibers in the veins. Furthermore, progressive narrowing of the lumen hastened the development of a collateral circulation, demonstrated on a venogram by the tortuous vessels and neovascularization up to the flap margin. To make it possible to predict and achieve complete survival of the arterialized venous flap, the following criteria must be considered: (a) an arterialized venous flap should be designed to contain most of the venous network in the center, (b) the arterial inflow has to be anastomosed to one afferent vein, (c) two or more efferent veins should drain the arterialized venous flap.

Anastomosis, Surgical↗
PubMed1998

Investigation of angiotensin II/AT1 receptors with carbon-11-L-159,884: a selective AT1 antagonist.

UNLABELLED: Antagonists of the angiotensin II AT1 receptor subtype have been recently introduced for treatment of arterial hypertension and for pharmacological studies of these receptors. The purpose of this work was to label such an antagonist with 11C and test the applicability of the radioligand for PET studies. METHODS: The potent and selective nonpeptide AT1 antagonist L-159,884 was labeled with 11C and injected intravenously into six dogs. Renal accumulation and kinetics of the radioligand were imaged with PET at baseline and after receptor blockade with 1 mg/kg MK-996. Time-activity curves were derived from the renal cortex and were analyzed by the Gjedde-Patlak plot to obtain the influx rate constant of the radioligand. RESULTS: There was selective radioligand binding in the kidneys, mainly located in the cortex. Within the time interval between 95 and 115 min postinjection, the radioactivity retained in the kidneys was 109 +/- 27 and 42 +/- 4 nCi/ml/mCi of the injected dose for the control and inhibition studies, respectively. The influx rate constant of the radioligand decreased from a baseline of 0.0298 +/- 0.0156 to a post-MK-996 value of 0.0098 +/- 0.0052. CONCLUSION: These results demonstrate distinct binding of 11C-L-159,884 in the renal cortex with a specific binding component suitable for quantitative PET imaging of angiotensin II/AT1 receptors.

Angiotensin II↗
PubMed1997

Crossed-cerebellar diaschisis in cerebral infarction: technetium-99m-HMPAO SPECT and MRI.

UNLABELLED: We studied 26 patients with a single supratentorial infarction using 99mTc-HMPAO SPECT and MRI to investigate the phenomenon of crossed-cerebellar diaschisis (CCD). METHODS: From the total single-photon emission counts obtained from each cerebellar hemisphere, the percent difference between the contralateral (CCH) and ipsilateral (ICH) cerebellar hemispheres [delta %cbll = (CCH-ICH)/ ICH x 100] was calculated. Both SPECT (SVD) and MRI volume deficit (MVD) were measured to examine their relationship with CCD. RESULTS: A CCD was observed in 12 of the 26 patients (46%) with cerebral infarction. There was no significant correlation between SVD and delta %cbll or MVD and delta %cbll in the patients with cerebral infarction. There were no significant differences in SVD and MVD between the patients with and without CCD. The frequency of CCD was significantly higher in the patients whose infarctions were in the frontoparietal lobes or the deep middle cerebral artery territory, including the basal ganglia and internal capsule (11/19) than in the patients whose infarctions were in other regions (1/7) (p = 0.048). The severely hemiparetic patients had a higher frequency of CCD and lower delta %cbll than the patients with milder or no hemiparesis (frequency, 5/5 compared with 6/18, p = 0.008; delta %cbll, -21.4% +/- 3.8% compared with -8.3% +/- 11.1%, p = 0.018). However, CCD also occurred in 5 of the 14 patients without hemiparesis and was not seen in 5 of the 12 hemiparetic patients. None of the patients with CCD demonstrated the apparent clinical signs of cerebellar dysfunction. CONCLUSION: The location rather than the extent and severity of the lesion may be the major determinant for the occurrence and magnitude of CCD in patients with cerebral infarction. Our results also support the notion that CCD is a consequence of the interruption of the corticopontocerebellar pathway at the supratentorial level.

Adult↗
PubMed1996

Effect of dopaminergic drugs on the in vivo binding of [3H]WIN 35,428 to central dopamine transporters.

[11C]WIN 35,428 (also designated [11C]CFT) is now being used in several positron emission tomography (PET) centers to image dopamine (DA) transporter sites in the mammalian brain. Whether and to what extent in vivo WIN 35,428 binding is influenced by intra- and extrasynaptic dopamine levels are largely unknown. The purpose of the present study was to evaluate the effects of various drugs, known to affect DA levels and release, on the binding of [3H]WIN 35,428 to central DA transporters in the mouse brain. D-Amphetamine, which releases DA from neurons and blocks the DA transporter directly, inhibited striatal [3H]WIN 35,428 binding in dose-dependent manner. Similarly, alpha-methyl-DL-p-tyrosine, an inhibitor of tyrosine hydroxylase, blocked [3H]WIN 35,428 binding, possibly via competitive inhibition by the metabolite p-hydroxyamphetamine. Specific binding of [3H]WIN 35,428 was insensitive to changes in synaptic DA levels caused by pretreatment of the animals with high doses of D2 receptor agonists (apomorphine, bromocriptine), antagonists (haloperidol) or the inhibitor of dopaminergic neuron firing gamma-butyrolactone (GBL). High doses (> 50 mg/kg) of L-DOPA (in combination with benserazide), however, reduced [3H]WIN 35,428 binding significantly, yet for a relatively short time (approximately 2.5 h). Chronic treatment with L-deprenyl elicited no changes in in vivo [3H]WIN 35,428 accumulation in the striatum. Neurotoxic damage of DA neurons caused by administration of high doses of amphetamine was detected in the striatum by a significant reduction in [3H]WIN 35,428 binding 7 days after cessation of amphetamine treatment. Thus, [3H]WIN 35,428 binding was only affected by neurotoxic loss of neurons, by administration of uptake inhibitors, or by some treatments which significantly elevate DA levels. Compounds which inhibit DA release or deplete DA acutely do not increase [3H]WIN 35,428 binding, suggesting that normal or "resting" levels of DA are not sufficient to alter [3H]WIN 35,428 binding in vivo. These findings are important for our understanding of the function and regulation of the DA transporter, as well as the in vivo binding of the radioligand [3H/11 C]WIN 35,428. Moreover, they will be important for the interpretation of PET studies in which [11C]WIN 35,428 is used to assess the integrity of dopaminergic neurons.

Amphetamine↗
PubMed1996

In vivo labeling of angiotensin II receptors with a carbon-11-labeled selective nonpeptide antagonist.

UNLABELLED: Angiotensin II (ANG II) initiates a variety of physiological effects by binding to high affinity receptors. Two ANG II receptor subtypes, AT1 and AT2, have recently been identified. This study was undertaken to evaluate [11C]L-159,884, an AT1 subtype selective nonpeptide antagonist, as a potential PET tracer. METHODS: Carbon-11-L-159,884 was prepared by alkylation of the nor precursor with [11C]methyliodide and was studied for its in vivo binding characteristics, biodistribution and kinetics in mice. The effects of PD-123319, an AT2-selective ANGII antagonist, as well as those of alpha- and beta-adrenergic drugs on [11C]L-159,884 binding were investigated also. RESULTS: Administration of the AT1 antagonists resulted in dose-dependent inhibition of [11C]L-159,884 binding in the kidneys, the organ with the highest density of AT1 receptors. Inhibition was also observed in the lungs and the heart. Adrenergic drugs did not influence [11C]L-159,884 binding to AT1 receptors. Kinetic studies showed rapid tracer uptake in the liver, kidneys, lungs and heart. Excretion of the radioactivity occurred primarily through the intestinal tract (> 20% in 90 min), with less than 8% excreted through the urine. CONCLUSION: The results suggest that [11C]L-159,884 binds in vivo to AT1 receptors in mouse kidneys, lungs and heart. This radiotracer appears to be a promising candidate for studying ANG II receptors in vivo by PET.

Angiotensin Receptor Antagonists↗
PubMed1995

Positron emission tomography imaging of serotonin transporters in the human brain using [11C](+)McN5652.

This paper presents the first Positron Emission Tomography (PET) images of the serotonin (5-hydroxytryptamine, 5-HT) transporter in the living human brain. PET imaging was performed in three healthy subjects after administration of [11C](+)McN5652 (the (+) enantiomer of trans-1,2,3,5,6,10 beta-hexahydro- 6-[4-(methylthio) phenyl]pyrrolo-[2,1-a] -isoquinolone), a radioligand previously shown to selectively label the 5-HT transporter in vivo in the mammalian (mouse and baboon) brain. To demonstrate the specificity of [11C](+)McN5652 binding, additional images were obtained in the same subjects after injection of [11C](-)McN5652, the pharmacologically inactive enantiomer, and, in two of the subjects, with [11C](+)McN5652 after pretreatment with the 5-HT uptake site blocker fluoxetine. Highest accumulation of [11C](+)McN5652 was observed in the midbrain, putamen, caudate nucleus, hypothalamus, and thalamus, regions known to contain high densities of 5-HT transporters. In these areas [11C](+)McN5652 concentrations rose steadily over 120 min. In contrast, with [11C](-)McN5652 and when the [11C](+)McN5652 binding was inhibited with fluoxetine, radioactivity concentrations declined after reaching a maximum (at 20 to 30 min). Inhibition studies with fluoxetine suggest that only with [11C](+)McN5652, there is specific binding. In the cerebellum, a region relatively void of 5-HT transporters, both [11C](+)McN5652 with and without fluoxetine block and [11C](-)McN5652 were released at approximately the same rate. The results of the studies indicate that [11C](+)McN5652 labels 5-HT transporter sites in the human brain. Quantitative PET imaging studies with this new tracer should provide valuable information on the status of these sites in health and disease.

Adult↗
PubMed1995

Positron emission tomography of 5-HT transporter sites in the baboon brain with [11C]McN5652.

[11C]McN5652 is a new radioligand specific for 5-hydroxytryptamine (5-HT; serotonin) transporters. In this study we used [11C]McN5652 to image the 5-HT transporter sites in baboon brain by positron emission tomography (PET). Dynamic PET studies were performed in three Papio anubis baboons. The animals were injected intravenously first with 11C-labeled (+)-McN5652([11C](+)McN5652), then with pharmacologically inactive enantiomer 11C-labeled (-)-McN5652 ([11C](-)McN5652); two animals received a third study with [11C](+)McN5652 after pretreatment with the specific 5-HT uptake site inhibitor fluoxetine (5 mg/kg). Initial uptake into the brain was similar for both [11C](+)McN5652 and [11C](-)McN5652. At later times (45-120 min after injection), only [11C](+)McN5652 showed a distribution characteristic for 5-HT uptake sites. In contrast, in studies with [11C](-)McN5652 and in those with [11C](+)McN5652 after 5-HT uptake site blockade with fluoxetine, 11C radioactivity concentrations were significantly lower and the distribution pattern was relatively even. The differences between [11C](+)-and (-)McN5652 were calculated for the time interval 95-125 min postinjection and used to estimate specific binding. Specific binding correlated well (r = 0.95, p < 0.001) with the known density of 5-HT uptake sites in human brain. These results indicate that [11C](+)McN5652 is suitable for PET imaging of 5-HT uptake sites in primate brain.

Animals↗