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Biomedical subjects

J K Chung

Publications and source records attributed to J K Chung.

At least 91 records · Page 5Linked to original sources
PubMed1994

Poor renal uptake of technetium-99m-DMSA and technetium-99m-MDP in a patient with Fanconi syndrome and near normal glomerular filtration rate.

We present a patient with Fanconi syndrome who demonstrated poor renal uptake of 99mTc-DMSA and high urinary concentration of the tracer. A 99mTc-DTPA scan was normal and the creatinine clearance only minimally decreased. These findings suggest that 99mTc-DMSA may be accumulated in the kidney by glomerular filtration and subsequent tubular reabsorption, with the nonabsorbed fraction appearing in the urine. In Fanconi Syndrome the tubular reabsorption of DMSA may also be reduced, thus explaining the poor renal uptake in this patient. A 99mTc-MDP bone scan showed faint renal uptake and diffuse high uptake mainly in the spine, demonstrating that the metabolic bone disease associated with Fanconi Syndrome can be another mechanism for poor renal visualization on bone scan.

Fanconi Syndrome↗
PubMed1994

Effect of hypocapnia on extracellular glutamate and glycine concentrations during peri-ischemic period in the rabbit hippocampus.

Glutamate (GLU) is a neurotransmitter. Massive release of GLU and glycine (GLY) into the brain's extracellular space may be triggered by ischemia, and may result in acute neuronal lysis or delayed neuronal death. The aim of this study was to evaluate the possible relationship between hyperventilation and the level of GLU and GLY during brain ischemia. Rabbits were anesthetized with halothane and oxygen. Group 1 was allowed to hyperventilate (PaCO2 25-35 mmHg). PaCO2 was maintained throughout the study. Group 2 was a normal control group that maintained normocapnia. Two global cerebral ischemic episodes were produced. Microdialysate was collected during the peri-ischemic and reperfusion periods from the dorsal hippocampus. GLU and GLY concentrations were determined using high-performance liquid chromatography. In the control group, GLU and GLY were significantly elevated during each episode of ischemia; these levels returned to baseline within 10 minutes after reperfusion. In contrast, in the hyperventilation group GLU and GLY concentrations increased during ischemia, but they were not statistically significant. We were able to demonstrate that hypocapnia during periischemic period lowered extracellular GLU and GLY concentrations. These results can explain a part of the protective action of hypocapnia during cerebral ischemia.

Animals↗
PubMed1994

Tumor concentration and distribution of carcinoembryonic antigen measured by in vitro quantitative autoradiography.

UNLABELLED: One of the most critical factors in successful immunoscintigraphy and radioimmunotherapy is the local concentration and distribution of the target antigen. The purpose of this study was to evaluate the concentration and distribution of carcinoembryonic antigen (CEA) in various carcinomas. METHODS: In vitro quantitative autoradiography was performed in carcinomas of the stomach (32 cases), colon (20 cases), breast (29 cases) and lung (26 cases). Frozen tumor sections were incubated with varying concentrations of 125I-labeled monoclonal antibody (Mab) CEA-79.1 (IgG2a), which is specific for CEA. Digitized autoradiographic images from these sections were compared to adjacent H & E and immunoperoxidase-stained sections. Computer analysis of specific antibody binding quantitated the maximal value (Bmax), which is equal to the concentrations of CEA. RESULTS: Stomach cancer expressed CEA in 31 cases (97%). All colon cancer specimens exhibited CEA and breast cancer expressed CEA in 24 cases (83%). In adenocarcinoma of the lung, CEA was measured in all specimens. The concentration of CEA did not vary significantly among the pathologic types or among the various degrees of differentiation in each carcinoma. CEA was expressed homogeneously in adenocarcinomas of the colon and lung. However, CEA exhibited a heterogeneous distribution in a significant number of breast cancer (42%) and bronchogenic squamous-cell carcinoma (78%) specimens. CONCLUSIONS: CEA was expressed in most cases of stomach, colon, breast and lung carcinomas. These carcinomas, however, exhibited wide variation in the concentration and distribution of CEA expression. The concentration and distribution of CEA in a particular tumor type should be considered before undertaking tumor targeting methods.

Adenocarcinoma↗
PubMed1993

Radioimmunoscintigraphy of advanced gastrointestinal carcinomas employing I-131 labeled CEA-79 monoclonal antibody.

CEA-79 is a murine IgG2a type monoclonal antibody (MoAb) generated using purified CEA from culture supernatants of a human colon cancer cell line, LS174T. The association constant and immunoreactivity of the I-131 labeled CEA-79 ranged from 2.0 to 3.2 x 10(9) l/mole, and from 54 to 74%, respectively. The purpose of this study was to evaluate the feasibility of radioimmunoscintigraphy employing MoAb CEA-79 in patients with advanced gastrointestinal carcinomas. Two mgs of MoAb CEA-79 was labeled with 111 MBq (3 mCi) of I-131, and infused intravenously in 6 stomach cancer and 16 colon cancer patients. Out of 6 patients with stomach cancer, immunoscintigraphy was able to detect the tumors in 4 cases. However, immunoscintigraphy found out tumors in all patients with colon cancer. Moreover, 1 patient with stomach cancer and 2 patients with colon cancer showed increased uptake of MoAb in the tumor lesions despite normal serum levels of CEA. We could conclude that this antibody has a potential as a new imaging agent for the diagnosis of gastrointestinal carcinoma.

Adult↗
PubMed1993

Clinical immunoscintigraphy of ovarian carcinoma using iodine-131-labeled 145-9 monoclonal antibody.

The monoclonal antibody (Mab) designated 145-9 recognizes CA125 antigen but binds to a different epitope than that recognized by OC125 antibody. This is a clinical study assessing the safety, kinetics and imaging sensitivity of Mab 145-9. Two milligrams of Mab were labeled with 111 MBq (3.0 mCi) of 131I and infused intravenously in 18 patients with ovarian carcinoma. Immunoscintigraphies were done at three, five, and seven days. There were no adverse reactions to the injection of this Mab. All immunoscintigraphies were considered positive. Immunoscintigraphy detected tumor lesions were confirmed in operative fields, in two patients with normal serum levels of CA125 and in four patients whose sonography and/or x-ray computed tomography showed negative findings. In five patients, immunoscintigraphy was repeated without any adverse reaction and revealed the progress of the carcinoma. Pharmacokinetic studies showed the steady-state volume of distribution (Vdss) to be 2772 +/- 466 ml (mean +/- s.d.), and clearance 51.3 +/- 12.7 ml/hr. In summary, immunoscintigraphies using 131I-labeled Mab 145-9 were done safely in patients with ovarian carcinoma. Preliminary results reveal a high sensitivity compared to radiological methods and tests currently in use.

Adult↗
PubMed1991

Evaluation of the protective effect of verapamil on reperfusion injury by 111In anticardiac myosin antibody in canine myocardial infarction.

We quantitated the protective effect of verapamil on reperfusion injury in canine myocardial infarct using 111In-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 of 111In-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.

Animals↗
PubMed1991

Absent or faint renal uptake on bone scan. Etiology and significance in metastatic bone disease.

A review of 14,296 unselected bone scans identified 889 scans showing absent or faint renal uptake. The majority of cases were associated with renal insufficiency (816/889; 91.8%), while widespread metastatic bone disease was the most common cause in a group of patients without renal disease (53/889; 6.0%). Of the 140 patients with prostate cancer, 108 (77.1%) had evidence of bone metastasis, 19 of whom (17.6%) revealed absent or faint renal uptake, demonstrating that poor renal uptake is more frequently associated with prostate cancer than with any other malignancy. Of note was that 162 out of 328 (49.4%) patients with stomach cancer at varying stages showed evidence of bone metastasis, and 14 of them (8.6%) showed poor renal images on bone scan. Interestingly, ankylosing spondylitis and rheumatoid arthritis were occasional causes of lack of renal activity (4 and 3 cases, respectively). A case of adult-form osteopetrosis, showing strikingly increased uptake mainly in the long bones with markedly diminished renal uptake, was also included in this study. Of the 53 bone scans with metastatic disease showing poor renal uptake, 44 (83.0%) revealed evidence of diffuse or multiple metastases in both spine and ribs, while 49 (92.5%) showed malignant involvement in three or more regions and 35 (66.0%) in four or more regions, suggesting widespread bone involvement in most cases.

Adult↗
PubMed1990

Localization of In-111 antimyosin Fab and 99mTc-pyrophosphate in reperfusion myocardial infarction model.

The myocardial uptake of In-111 antimyosin Fab and Tc-99m pyrophosphate was studied in dogs undergoing coronary artery occlusion for 90 minutes followed by reperfusion. The regional myocardial blood flow was determined by injecting Sc-46 labeled microsphere and was related to the relative concentrations of In-111 antimyosin and Tc-99m pyrophosphate. There was an inverse linear correlation between In-111 antimyosin Fab localization and the regional blood flow in both the subendocardial (r = 0.81) and subepicardial myocardium (r = -0.80). The greatest uptake of antimyosin was observed in areas of severe blood flow reduction (0-10% of normal). On the other hand, there was no correlation between the Tc-99m pyrophosphate uptake and the degree of blood flow reduction. Maximal subendocardial localization of Tc-99m degree of blood flow reduction. Maximal subendocardial localization of Tc-99m pyrophosphate was observed in areas where the blood flow was reduced to 31-50% of the normal. In the case of the subepicardium, the greatest uptake was localized to areas of 0 to 10% of the normal flow. In addition, there was significant myocardial uptake in regions where the blood flow was minimally reduced (greater than 81%). This study suggests that In-111 antimyosin Fab is a specific and quantitative tool in the evaluation of myocardial necrosis.

Animals↗
PubMed1990

Changes in the properties of the thyrotropin receptor antibody in patients with Graves' disease after radioiodine treatment.

We investigated the effect of a single dose of 131I upon thyrotropin receptor antibodies (TRAb) in 21 patients with Graves' disease. The thyrotropin receptor antibodies were assessed by parallel measurements of thyrotropin binding inhibitor immunoglobulin (TBII), thyroid stimulating antibody (TSAb) and thyroid stimulation blocking antibody (TSBAb) in serum by radoreceptor assay, stimulation of adenlate cyclase and inhibition of TSH-stimulated adenylate cyclase activation in FRTL-5 cells, respectively. Prior to radioiodine treatment, TBII was detected in all 21 patients and TSAb in 19 patients. After radioiodine treatment, TBII activities did not change during the 12-months observation period, but in eight patients TSAb activities gradually decreased and were undetectable at the end of the 12-month observation period. Persistence of TSAb was not associated with the clinical outcome. Eight patients developed hypothyroidism within one year after radioiodine treatment. Three of the hypothyroid patients developed TSBAb, and the appearance of TSBAb coincided with the development of hypothyroidism. These results suggest that TSBAb might develop after radioiodine treatment in a minority of patients with Graves' disease and that the appearance of TSBAb, in addition to radiation-induced thyroid destruction, might be involved in the development of hypothyroidism following radioiodine treatment.

Adolescent↗
PubMed1989

Changes in the properties of the thyrotropin receptor antibody in patients with Graves' disease after radioiodine treatment.

We investigated the effect of a single dose of 131I upon thyrotropin receptor antibodies (TRAb) in 21 patients with Graves' disease. The thyrotropin receptor antibodies were assessed by parallel measurements of thyrotropin binding inhibitor immunoglobulin (TBII), thyroid stimulating antibody (TSAb), and thyroid stimulation blocking antibody (TSBAb) in serum by radioreceptor assay, stimulation of adenylate cyclase and inhibition of TSH-stimulated adenylate cyclase activation in FRTL-5 cells, respectively. Prior to radioiodine treatment TBII was detected in all 21 patients and TSAB in 19 patients. After radioiodine treatment TBII activities did not change during 12 months observation period, but in eight patients TSAb activities gradually decreased and were undetectable at the end of a 12 month observation period. Persistence of TSAb was not associated with clinical outcome. Eight patients developed hypothyroidism within 1 year after radioiodine treatment. Three of the hypothyroid patients developed TSBAb, and the appearance of TSBAb coincided with the development of hypothyroidism. These results suggest that TSBAb might develop after radioiodine treatment in a minority of patients with Graves' disease, and that the appearance of TSBAb, in addition to radiation induced thyroid destruction, might be involved in the development of hypothyroidism following radioiodine treatment.

Adolescent↗
PubMed1988

Computerized quality control of radioimmunoassay in Korea.

Automated data processing and quality control of radioimmunoassays offer not only increased speed but also a more thorough and statistically rigorous analysis of results. An external quality assessment scheme for serum thyroxine, triiodothyronine and thyroid stimulating hormone (TSH) assays was performed in five nuclear medicine laboratories in Korea to compare with the assay performances of the World Health Organization Radioimmunoassay Program. The required radioimmunoassay kits were supplied through the International Atomic Energy Agency (IAEA). We have determined the weighted root mean squared error, and variance ratio as the indices of standard curve and also the average batch coefficient of variation (ABCV) as the parameters of response error relationship curve and precision profile. There was a good fit for the triiodothyronine assay, but 3 of 5 laboratories showed possible bad fit in the T4 and TSH assay systems. The ABCV was less than 5 percent for the T3 and T4 assay system, however for the TSH system, only 1 laboratory showed the ABCV value of less than 5 percent. We have also calculated the within batch variation (drift) and between laboratory variations.

Electronic Data Processing↗
PubMed1986

Extended sensitivity for the calcium selective electrode.

Sensitivity of calcium-selective electrodes heretofore has been limited to calcium concentrations above 10(-8) M in the absence of competing ions. We describe the use of calcium buffers to stabilize the free calcium in the reference electrode. Electrode calibration is linear to 10(-8) M and is curvilinear to 10(-11) M in the presence of 0.1 M ionic strength. Selectivity with respect to competing cations, magnesium, potassium, sodium, and hydrogen is preserved. Electrode response time is less than 2 s for small changes in calcium activity. Response range is linear over 9 log units of calcium activity. Potential-time stability is less than 10 mV/h at saturation currents. Although the silver-silver chloride terminals are photosensitive throughout the visible and near-ultraviolet regions, housing the reference and indifferent in opaque barrels avoids false photovoltaic response.

Buffers↗
PubMed1975

Nature of the Kanagawa phenomenon of Vibrio parahaemolyticus.

In a study of the Kanagawa phenomenon of Vibrio parahaemolyticus, both Kanagawa-positive and -negative strains were found to produce hemolytic factors that could not be differentiated on Wagatsuma blood agar. The presence of fermentable carbohydrates in media containing high concentrations of NaCl promoted the growth of V. parahaemolyticus and resulted in a marked decrease in medium pH and increased hemolysin production. The Kanagawa hemolysis of test strains differed according to the carbohydrates added. Clearly defined Kanagawa hemolysis was observed in blood agars of high salt content, but the distinction was lost in media containing 3% NaCl. From the results of this study, the Kanagawa hemolysis was interpreted as an expression of quantitative difference in hemolysin production, a conclusion that is clearly demonstrated on special blood agar of high salt content.

Antibody Formation↗
PubMed1974

Enrichment of Vibrio parahaemolyticus in a simple medium.

A medium which contained 3% NaCl and 0.2% Teepol in 1/15 M phosphate buffer was prepared and was evaluated to be a useful enrichment medium for the isolation of Vibrio parahaemolyticus in marine specimens. Glucose salt Teepol broth produced a poorer result than direct culture.

Agar↗