Biomedical subjects

H K Lim

Publications and source records attributed to H K Lim.

117 records · Page 7Linked to original sources

PubMedDate not supplied

Determination of LSD in urine by capillary column gas chromatography and electron impact mass spectrometry.

A procedure for the determination of LSD (lysergic acid diethylamide) in urine at concentrations as low as 0.5 ng/ml is presented. After addition of deuterium-labeled LSD as the internal standard, a rapid n-butyl chloride extraction of LSD from urine at pH 8 is followed by formation of the trimethylsilyl (TMS) derivative by treatment with N,O-bis(trimethylsilyl)trifluoroacetamide. The TMS derivative of LSD is identified and quantified by selected ion monitoring with a fused-silica capillary column and electron impact ionization. The procedure was used to monitor LSD concentrations in urine for eight hours following oral administration of 70.5 micrograms of LSD to two human volunteers. Concentrations of LSD determined by the assay are compared with concentrations determined by two other methods of analysis, a radioimmunoassay and a high-performance liquid chromatographic (HPLC) assay. Data concerning the stability of LSD in urine are also presented.

Chromatography, Gas↗

PubMedDate not supplied

Transient subsegmental hepatic parenchymal enhancement on dynamic CT: a sign of postbiopsy arterioportal shunt.

PURPOSE: Our goal was to verify the correlation between the arterioportal shunt caused by liver biopsy injury and wedge-shaped early transient subsegmental parenchymal enhancement (TSPE) of the liver during helical dynamic CT. METHOD: Twenty-one consecutive patients with suspected hepatic tumor underwent percutaneous needle biopsy. Helical dynamic CT scans at arterial, portal venous, and delayed phases were obtained before and after biopsy. CT images were reviewed for the presence of TSPE during the arterial phase of dynamic CT. Hepatic arteriograms were obtained in all patients and reviewed for the presence of arterioportal shunt. RESULTS: Wedge-shaped TSPE was observed on postbiopsy CT in 8 (38%) of the 21 patients along the needle path. In all of these patients subsegmental arterioportal shunt was confirmed by hepatic angiograms. CONCLUSION: Wedge-shaped TSPE is commonly observed along the biopsy needle path and is due to arterioportal shunt caused by biopsy.

Adult↗

PubMedDate not supplied

Intestinal metastases from gastric adenocarcinoma: helical CT findings.

PURPOSE: The purpose of this work was to describe the helical CT findings of intestinal metastasis from gastric adenocarcinoma. METHOD: Twenty-three patients with intestinal metastasis from gastric adenocarcinoma found at helical CT were included. CT findings and clinical and pathologic data were reviewed. RESULTS: The most common characteristic finding was target-like concentric bowel wall thickening (thick inner high-outer low, n = 18) involving multiple long segments with progressive thickening of the enhancing inner layer. Fifteen cases (65%) involved multiple sites, and the ascending colon (n = 12) and rectum (n = 11) were the two most common sites. Peritoneal carcinomatosis (n = 15, 65%) and bowel obstruction (n = 14, 61%) were common associated findings. Regarding the primary lesion, the majority was linitis plastica (n = 16) and poorly differentiated adenocarcinoma with or without signet-ring cell differentiation (n = 14). CONCLUSION: Intestinal metastasis from gastric adenocarcinoma, especially of the linitis plastica type, most commonly showed target-like long segmental wall thickening with a characteristically thick inner enhancing layer on helical CT.

Adenocarcinoma↗

PubMedDate not supplied

Detection of hepatocellular carcinoma: combined T2-weighted and dynamic gadolinium-enhanced MRI versus combined CT during arterial portography and CT hepatic arteriography.

PURPOSE: The purpose of this study was to compare the preoperative detectability of hepatocellular carcinomas (HCCs) using combined T2-weighted and dynamic gadolinium-enhanced MRI and combined CT during arterial portography (CTAP) and CT hepatic arteriography (CTHA). METHOD: Thirty-three patients with 43 HCCs underwent T2-weighted and dynamic gadolinium-enhanced MRI and combined CTAP and CTHA. The diagnosis was established by pathologic examination following surgical resection in 26 patients and by biopsy in 7 patients. The MR protocol included fast SE with two TEs (including T2-weighted imaging) and precontrast and gadolinium-enhanced T1-weighted fast multiplanar spoiled gradient-recalled echo images with dynamic study. The MR images of all sequences and the paired CTAP and CTHA images were independently reviewed by three radiologists. Image review was conducted on a segment-by-segment basis. Diagnostic accuracy was evaluated with receiver operating characteristic analysis. RESULTS: The accuracies (Az values) of MRI of all sequences and combined CTAP and CTHA for all observers were 0.960 and 0.959, respectively. The mean sensitivities of MRI and CT were 90 and 94%, respectively. The differences were not statistically significant. The mean specificity of MRI (99%) was significantly higher than that of combined CTAP and CTHA (92%). CONCLUSION: Combined T2-weighted and dynamic gadolinium-enhanced MRI is as accurate as combined CTAP and CTHA for preoperative detection of HCCs.

Adult↗

PubMedDate not supplied

Pharmacological profile of the 5-HT(2C) receptor agonist WAY-163909; therapeutic potential in multiple indications.

The 5-HT(2C) receptor subtype has been implicated in a wide variety of conditions including obesity, anxiety, depression, obsessive compulsive disorder, schizophrenia, migraine and erectile dysfunction and as a consequence has received considerable attention as a target for drug discovery. Here we review the pharmacological, pharmacokinetic and toxicological profile of WAY-163909 {(7bR,10aR)-1,2,3,4,8,9,10,10a-octahydro-7bH-cyclopenta-[b][1,4]diazepino[6,7,1hi]indole}, a novel 5-HT(2C) receptor selective agonist. Consistent with a potential therapeutic utility in obesity, schizophrenia and depression WAY-163909 was found to have robust dose-dependent effects in animal models of obesity, psychotic-like behavior or depression.

Animals↗

PubMedDate not supplied

Radiologic features of vasculitis involving the gastrointestinal tract.

Vasculitides can cause local or diffuse pathologic changes in the gastrointestinal tract, resulting in nonspecific paralytic ileus, mesenteric ischemia, submucosal edema and hemorrhage, or bowel perforation or stricture. The extent and clinical course of disease depend on the size and location of the affected vessel and the histologic characteristics of the lesion. Vasculitis may primarily involve large vessels (eg, giant cell arteritis, Takayasu arteritis), medium-sized vessels (eg, polyarteritis nodosa, Kawasaki disease, primary granulomatous central nervous system vasculitis), or small vessels (eg, Wegener granulomatosis, Churg-Strauss syndrome, microscopic polyangiitis, Henoch-Schönlein syndrome, systemic lupus erythematosus, rheumatoid vasculitis, Behçet syndrome). Radiologic findings in various types of vasculitis often overlap considerably and therefore have limited value in making a specific diagnosis. Nevertheless, the possibility of vasculitis should be considered whenever mesenteric ischemic changes occur in young patients, are noted at unusual sites (eg, stomach, duodenum, rectum), have a tendency to concomitantly involve the small and large intestine, and are associated with genitourinary involvement. Knowledge of systemic clinical manifestations in affected patients may suggest and even help establish the specific diagnosis.

Angiography↗

PubMedDate not supplied

Radiofrequency thermal ablation of hepatocellular carcinomas.

Although surgical resection remains the best option as potentially curative therapy for hepatocellular carcinoma, radiofrequency thermal ablation has begun to receive much attention as an effective minimally invasive technique for the local control of unresectable malignant hepatic tumors. Most recent radiofrequency devices equipped with a powerful generator and larger needle electrode permit larger thermal lesions, up to 5 cm in diameter, with a single ablation. In this article, the author reviews the technical developments and early clinical results obtained with radiofrequency ablation techniques.

Aged↗

PubMedDate not supplied

Isolation, purification, and characterization of two new chemical decomposition products of methylazoxyprocarbazine.

We have previously reported that the antineoplastic agent, procarbazine, in aqueous solutions was chemically oxidized to its azoxy metabolites (methylazoxy and benzylazoxy). To determine if there was additional metabolism of the most active metabolite, methylazoxyprocarbazine, it was incubated in the presence and absence of CCRF-CEM human leukemia cells. Incubations were extracted, and potential metabolites were detected by HPLC with UV detection and by combined HPLC and thermospray mass spectrometric analysis. The major metabolite identified by HPLC with UV detection of the extracts was N-isopropyl-p-formylbenzamide; this was identified by comparison of its retention time with that of a synthesized standard. This identification was further corroborated by HPLC/thermospray mass spectrometry (LC/MS). Analysis of the extracts by LC/MS also showed the presence of a closely eluting peak that had a protonated molecular ion at m/z 207. This new metabolite was identified as N-isopropyl-(benzene-1,4-bis-carboxamide) by 1H NMR and gas chromatography/ion trap mass spectrometry. This metabolite is postulated to arise from breakage of the N-N bond in the hydrazine portion of the molecule. Reconstructed ion (m/z 236) current profiles from the analysis of the cell extracts indicated that there was only a trace amount of methylazoxyprocarbazine left after a 72-hr incubation. Interestingly, a peak with the same molecular weight as the parent compound (methylazoxyprocarbazine) was observed in the cellular incubations and also in extracts of control incubations in which methylazoxyprocarbazine was incubated in medium without cells. This unknown was silylated and identified as a hydroxyazo compound by an ion trap mass spectrometer operated under both single and multiple-stage mass analysis. Formation of this decomposition product appears to involve a novel intramolecular rearrangement of methylazoxyprocarbazine in solution. This pathway may be responsible for the formation of the ultimate cytotoxic species by chemical decomposition of procarbazine.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

[A study on menopausal symptoms and health needs among middle aged women].

During the middle age of a woman's life cycle, several health changes and problems occur. Therefore, middle aged women must manage their health and maintain quality life by coping with bodily changes. However, today there is not enough research and health programs for middle aged women. Data from the study will be used for health promotion program development of middle aged women. Data was collected from January 21 to 24, 1995 by telephone interview. Four hundred middle aged women between 40 and 59 years old and living in Chon Ju City were interviewed. The results of this study were as follow: 1. Frequency rate of menopausal symptoms was 38.4%. The most serious menopausal symptom was psychosomatic symptom. Mean score orders of experienced symptoms were back pain, joint pain (1.80), nervousness (1.80), general weakness (1.67). 2. The most important problems as perceived by the clients were children (45.8%), health (24.0%) and economics (7.8%). The most serious health problems were concerning the muscle-skeletal system (45%) such as arthritis, spinal disk problems and osteoporosis. Adult diseases (14.5%) such as hypertension and diabetes were also health concerns. Health management activities reported were exercise (22.5%), social activity (12%) and inactivity (53%). 33% of clients were interested in health groups and they wanted a program of health education, exercise and social activity to be provided. 3. General characteristic variables were significantly related to the level of menopausal symptoms as follows: age (t = -2.06, p = 0.040), status of marriage (t = -3.56, p = 0.000), educational level (F = 4.35, p = 0.05) and menopausal status (t = 4.37, p = 0.000).

Adult↗