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C H Moon

Publications and source records attributed to C H Moon.

33 records · Page 2Linked to original sources
PubMed1998

A new silent magnetic resonance imaging using a rotating DC gradient.

A new approach to silent MR imaging using a rotating DC gradient has been explored and experimentally studied. Acoustic or sound noise has been one of the problems in examining patients, mainly due to the fast gradient pulsings in interaction with the main magnetic field. The sound noise has been noted to be proportionately louder as the magnetic field strength becomes larger. In this report, we describe a new imaging technique using a mechanically rotating DC gradient coil. The rotating DC gradient coil can effectively replace both phase encoding as well as readout gradient pulsings, and data obtained in this manner can provide a set of projection data that later can be used for projection reconstruction. With some interpolation techniques one can also perform conventional two-dimensional fast Fourier transform image reconstruction. The sound noise intensity compared with the conventional imaging technique, such as the spin-echo sequence, has been reduced down to about -20.7 dB or 117.5 times with this new technique. The experimental pulse sequence and its principle are described and images obtained by the new silent MR imaging technique are reported.

Equipment Design↗
PubMed1998

Brazilin inhibits activities of protein kinase C and insulin receptor serine kinase in rat liver.

Hypoglycemic action of brazilin was found to be based on the improvement of peripheral glucose utility, and this action might be correlated with the insulin action pathway. In the present study we investigated the effect of brazilin on the insulin receptor autophosphorylation, protein kinase C (PKC), protein phosphatase and insulin receptor serine kinase in order to confirm whether the hypoglycemic mechanism is concerned with insulin action pathway. Brazilin was found to inhibit PKC and insulin receptor serine kinase, which are involved in the regulation of insulin signal pathway. But any significant effect was not shown on insulin receptor tyrosine kinase activity, autophosphorylation and phosphatase activity. These findings suggest that brazilin might enhance insulin receptor function by decreasing serine phosphorylation, which might mediate hypoglycemic effect of brazilin.

Animals↗
PubMed1998

Psychosocial factors limit outcomes after trauma.

BACKGROUND: Psychological morbidity compromises return to work after trauma. We demonstrate this relationship and present methods to identify risks for significant psychological morbidity. METHODS: Thirty-five adults were evaluated prospectively for return to functional employment after injury using demographic data, validated psychological and health measures, and the Michigan Critical Events Perception Scale. Evaluation was conducted at admission and at 1 and 5 months after injury. RESULTS: Poor return to work at 5 months was attributable to physical disability (p < 0.05) and psychological disturbance (p < 0.05) in a regression model that controlled for preinjury employment and psychopathologic factors as well as injury severity. A high score on the Impact of Events Scale administered during acute admission predicted development of acute stress disorder at 1 month (p < 0.01, odds ratio (OR) = 9.4) and posttraumatic stress disorder at 5 months (p < 0.05, OR = 6.7). Peritraumatic dissociation on the Michigan Critical Events Perception Scale was predictive for development of acute stress disorder (p < 0.05, OR = 5.8) at 1 month and posttraumatic stress disorder (p < 0.05, OR = 7.5) at 5 months. CONCLUSION: Psychological morbidity after injury compromises return to work independent of preinjury employment and psychopathologic condition, Injury Severity Score, or ambulation. A high Impact of Events Scale score or peritraumatic dissociation at admission predicts this morbidity.

Activities of Daily Living↗
PubMed1998

Cardioprotective effects of KR-30450, a novel K+(ATP) opener, and its major metabolite KR-30818 on isolated rat hearts.

The cardiac effects of KR-30450 ((-)-(2R)-2-([1,3]-dioxolan-2-yl)-2-methyl-4-(2-oxopyrrolidin++ +-1-yl)-6-nitro-2H-1-benzopyran), a newly synthesized potassium channel activator, and its major metabolite KR-30818 ((-)-(2R)-2-hydroxymethyl-2-methyl-4-(2-oxopyrrolidin-1-yl)-6-nitr o-2H-1-benzopyran) were compared with those of lemakalim, a prototype of this class, in isolated globally ischemic rat hearts. KR-30450 and KR-30818 significantly improved reperfusion cardiac function (LVDP, left ventricular developed pressure; double product, LVDP x heart rate/1000), their potency being 5.2-fold and 0.7-fold greater than lemakalim (ED50 for recovering predrug double product: 0.10, 0.80 and 0.54 microM, respectively). KR-30450 and KR-30818 significantly attenuated reperfusion contracture and lactate dehydrogenase release with potency greater than and equal to lemakalim, respectively. They significantly increased time to contracture (TTC) during ischemia in a dose-dependent manner with a greater potency than lemakalim (EC25 for increasing TTC: 1.2, 2.1 and 3.2 microM, respectively). The protective effects of three compounds on the measured parameters were reversed by glyburide, a selective K+(ATP) blocker. In non-ischemic hearts, KR-30450 and lemakalim exerted weak negative inotropism at high concentrations and KR-30818 had no effects, whereas the three compounds significantly increased coronary flow at doses studied. Glyburide completely reversed preischemic cardiodepressant effects of these compounds but not their effects on coronary flow. In conclusion, KR-30450, a recently developed K+(ATP) opener, exerted more potent cardioprotective effects than lemakalim, and its major metabolite KR-30818 may play a significant role in its action in vivo.

Animals↗
PubMed1998

Giant-cell interstitial pneumonia in a gas station worker.

Giant-cell interstitial Pneumonia (GIP) is a very uncommon respiratory disease. The majority of cases of GIP are caused by exposure to cobalt, tungsten and other hard metals. In this report, we describe GIP in a patient who worked in gas station and dealt in propane gas vessels. He presented with clinical features of chronic interstitial lung disease and underwent an open lung biopsy that showed DIP-like reaction with large numbers of intra-alveolar macrophages and numerous large, multinucleated histiocytes which were admixed with the macrophages. Analysis of lung tissue for hard metals was done. Cobalt was the main component of detected hard metals. Corticosteroid therapy was started and he recovered fully.

Giant Cells↗
PubMed1998

Pharmacokinetics of losartan and its metabolite, EXP3174, after intravenous and oral administration of losartan to rats with streptozotocin-induced diabetes mellitus.

The pharmacokinetics of losartan and its active metabolite, EXP3174, were investigated after intravenous and oral administration of the drug, 5 mg/kg, to control rats and streptozotocin-induced diabetes mellitus rats (SIDRs). After 1-min intravenous infusion, the mean arterial plasma concentrations and the resultant area under the plasma concentration-time curve from zero to infinity (AUC) of both losartan and EXP3174 were not significantly different between control rats and the SIDRs. However, the renal clearance (CLR) of losartan (0.181 versus 0.0815 ml/min/kg) and EXP3174 (0.0677 versus 0.0277 ml/min/kg) were significantly faster in SIDRs than in control rats due to significant increase in glomerular filtration rate. After oral administration, the mean arterial plasma concentrations and the resultant AUC of losartan (97 versus 166 micrograms min/ml) and EXP3174 (244 versus 423 micrograms min/ml) were significantly lower in SIDRs than in control rats. The absolute extent of oral bioavailability of losartan, F, (32.5 versus 55.1%) decreased considerably in SIDRs and it was possibly due to the reduced gastrointestinal absorption of losartan by gastrointestinal disorders occurring in the diabetic state. The low F in both groups of rats was at least partially due to the increase in first-pass effects. The CLR of losartan (0.207 versus 0.101 ml/min/kg) and EXP3174 (0.0615 versus 0.0196 ml/min/kg) were significantly faster in SIDRs than in control rats after oral administration of losartan.

Administration, Oral↗
PubMed1996

Pharmacokinetic changes of methotrexate after intravenous administration to streptozotocin-induced diabetes mellitus rats.

The pharmacokinetic changes of methotrexate (MTX) were investigated after 1-min intravenous (iv) administration of MTX, 8 mg/kg, to the control and the streptozotocin-induced diabetes mellitus (SIDM) rats. After 1-min iv infusion of MTX, plasma concentrations of MTX declined polyexponentially for both groups of rats. In the SIDM rats, the plasma concentrations of MTX were significantly lower up to 5 min, however, significantly higher from 60 min than those in the control rats. In the SIDM rats, the volume of distribution at steady state was significantly higher (1010 versus 265 ml/kg) than that in the control rats, and this was due to the significantly increased unbound fraction of MTX (73.0 versus 58.1%) in serum of SIDM rats. This resulted in a significantly increased mean residence time (53.2 versus 13.8 min) in the SIDM rats. All 12 control rats survived until sacrificed (24 hr), however, 6 out of 15 SIDM rats died within 6 h after iv administration of MTX, suggesting that the iv doses of MTX in diabetes mellitus patients may need to be modified if the present rat data could be extrapolated to human beings.

Animals↗
PubMed1996

Pharmacokinetic changes of methotrexate after intravenous administration to uranyl nitrate-induced acute renal failure rats.

The pharmacokinetic changes of methotrexate (MTX) were investigated after 1-min intravenous (iv) administration of MTX, 8 mg/kg, to the control and the uranyl nitrate-induced acute renal failure (U-ARF) rats. The impaired kidney and liver functions were observed by pretreatment with urinary nitrate based on physiological parameters of plasma and urine, and the tissue microscopy. After 1-min iv infusion of MTX, the plasma concentrations of MTX (except at 1 min) and the total area under the plasma concentration-time curves of MTX (542 versus 297 micrograms min/ml) increased significantly in the U-ARF rats when compared to those in the control rats. This was due to the significantly slower in total body clearance (CL) of MTX (15.2 versus 27.5 ml/min/kg) in the U-ARF rats than that in the control rats. The significantly slower in CL of MTX in the U-ARF rats was due to the significantly slower both renal (1.01 versus 8.39 ml/min/kg, because of the considerably decreased renal tubular secretion of MTX) and nonrenal (14.2 versus 19.1 ml/min/kg, because of the considerably decreased liver metabolism) clearances in the U-ARF rats. All 11 control rats survived until sacrificed (24 h), however, 5 out of 15 U-ARF rats died within 7 h after iv administration of MTX. If the present rat data were to be extrapolated to human beings, iv dose of MTX need to be modified in the acute renal failure patients.

Acute Kidney Injury↗
PubMed1995

Staurosporine induces de novo synthesis of prostaglandin H synthase-2 in rat alveolar macrophages.

This study was initiated to investigate the possible involvement of prostaglandin H synthase in the staurosporine-induced prostaglandin production. The time course of prostaglandin H synthase activity in macrophages treated with staurosporine (20 nM) showed that the maximum activity was reached in 20 h. The stimulatory effect of staurosporine on thromboxane B2 production was maximum at 50 nM staurosporine and this effect was reversed at higher concentrations. Immunoprecipitation of 35S-labeled enzyme using an antibody specific for prostaglandin H synthase-2 paralleled the changes in enzyme activity. These results indicate that increased de novo synthesis of prostaglandin H synthase-2 is largely, if not solely, responsible for staurosporine-stimulated prostaglandin production in macrophages.

Alkaloids↗
PubMed1995

The first human case of Clinostomum complanatum (Trematoda: Clinostomidae) infection in Korea.

The authors present the first human case of Clinostomum pharyngitis in Taegu, Korea. The patient was a 56-year old male who visited an otolaryngology clinic due to foreign body sensation and pain of the pharyngeal region for 3-4 days. He used to eat raw fresh-water fish. Otolaryngological examinations revealed a living worm adhered to the right posterior pharyngeal wall. The worm removed was identified as C. complanatum after morphological observations. It is likely that more attention should be paid to eating raw fresh-water fish in Korea with regards to Clinostomum pharyngitis.

Animals↗
PubMed1995

The first human case of Diplogonoporus balaenopterae (Cestoda: Diphyllobothriidae) infection in Korea.

The first human case of Diplogonoporus balaenopterae infection is reported in Korea. The patient was a 41-year old male who passed a part of cestode strobila, about 1 m long, spontaneously in his stool. He used to eat raw marine fish when he drank alcohol. The worm was identified as D. balaenopterae after morhological observations and literature review. Results of laboratory examination were within normal limits except for slight eosinophilia (6%) and extraordinarily high serum Ig E level (10,182 IU/ml).

Adult↗
PubMed1995

Demonstration of the second intermediate hosts of Clinostomum complanatum in Korea.

A species of metacercariae recovered from the fresh-water fish, collected from Kaumji (Pond), Kaechonji (Pond) and Ssanggyechon (River). Uisong-gun, Kyongsangbuk-do, Korea, was identified as Clinostomum complanatum by morphological observation and experimental infection to chicks. The excysted metacercariae, tongue-shaped and progenetic, were 3.28-4.27 mm in length and 0.94-1.46 mm in width. The adult flukes recovered from the chicks four days after infection were 4.20-4.86 mm long and 1.14-1.49 mm wide. Twelve species of the fresh-water fish were found to be infected with the metacercariae. The infection rate ranged from 1.6% (Zacco temminkii) to 88.9% (Acheilognathus rhombea and Microphysogobio yaluensis). The intensity was highest in Carassius auratus (13.0/fish infected) and the abundance (relative density) was highest in A. rhombea (7.8/fish examined). This survey demonstrated for the first time the source of human infection by C. complanatum in Korea.

Animals↗
PubMed1990

Continuous determination of extracellular space and changes of K+, Na+, Ca2+, and H+ during global ischaemia in isolated rat hearts.

Isolated rat hearts were perfused according to the Langendorff technique and prepared to allow the measurement of left ventricular pressure (LVP), the first derivative of LVP (dP/dt), coronary perfusion pressure (CPP) and heart rate (HR). The hearts were perfused with a modified Krebs-Henseleit solution (KHS; control group) or KHS containing tetramethylammonium-chloride (TMA; 100 microM), which did not influence heart haemodynamics or extracellular potassium accumulation during global ischaemia (GI). TMA was used as a marker to determine changes in the size of the extracellular space (ECS) during 60 min of GI. Extracellular concentrations of K+, Na+, Ca2+, H+ and TMA were measured using double-barreled polyvinyl chloride (PVC) mini-electrodes. Relative changes in the ECS size and net cation movements were calculated from the extracellular TMA and cation concentrations. After 60 min of GI ECS decreased by 74% due to a water shift into the intracellular space (ICS). Within 10 s after the onset of GI extracellular potassium concentration increased in a typical triphasic pattern. A biphasic net efflux of K+ was maximal 2 and 15 min after the onset of ischaemia interrupted by a maximal uptake after 7 min, probably due to the stimulation of the Na+/K+ ATPase. The changes in extracellular sodium and calcium concentrations were biphasic; showing an initial increase occurring approximately during the first 20 min after the onset of GI followed by a decrease. Despite the initial increase of extracellular Na+ and Ca2+ maximal net influx of Na+ and Ca2+ were calculated after 2 and 19 min of GI. Accumulation of H+ in the extracellular space occurred mainly during the first 20 min of GI. It is concluded that, (1) TMA is a useful marker for continuous measurement of changes in the size of the ECS during GI; (2) Changes in extracellular ion concentration are influenced markedly by a water shift from the ECS into the ICS; (3) Stimulation of the Na+/K+ pump causes a transient net uptake of K+ and reduces the net influx of Na+; (4) Ca2+ uptake is decreased transiently probably by increased Ca2(+)-ATPase activity; (5) Energy dependent protective mechanisms for the maintainance of intracellular ionic homeostasis are exhausted after approximately 15 to 20 min of GI in isolated working rat hearts.

Animals↗
PubMed1985

Pharmacokinetics of N-propylajmaline in relation to polymorphic sparteine oxidation.

In order to determine whether the metabolism of the antiarrhythmic drug N-propylajmaline is under the same genetic control as sparteine metabolism, the pharmacokinetics of this antiarrhythmic drug were studied in a groups of six extensive and four poor metabolizers of sparteine. Pronounced differences in terminal half-life, total plasma clearance, metabolic clearance and urinary excretion of N-propylajmaline were observed between extensive and poor metabolizers. A close relationship between the total clearance and metabolic clearance of N-propylajmaline and sparteine could be demonstrated. Clinically available N-propylajmaline is a 55% to 45% mixture of the i- and n-diastereomers. The extensive metabolizers exhibited stereoselective metabolism; the i-diastereomer was preferentially metabolized. Poor metabolizers were characterized by a loss of this stereoselective metabolism. Five subjects were treated for 7 days with a daily N-propylajmaline dosage of either 60 mg or 20 mg. Since a close relationship between the clearance of N-propylajmaline and the metabolic ratio of sparteine had been observed after single dosing the metabolic ratio of sparteine was used to predict N-propylajmaline steady-state plasma concentrations during multiple dosing. Only in two extensive metabolizers with a metabolic ratio less than 0.4 predicted and observed, steady-state plasma concentrations were in good agreement. In the other three subjects observed steady-state plasma concentrations were appreciably higher than predicted. In these three subjects metabolic N-propylajmaline clearance decreased indicating saturation N-propylajmaline metabolism during multiple dosing. The data indicate that N-propylajmaline metabolism is subject to a genetic polymorphism controlled by the sparteine/debrisoquine gene locus.

Adult↗