Biomedical subjects

C Y Kim

Publications and source records attributed to C Y Kim.

At least 163 records · Page 9Linked to original sources

PubMed1991

Specificities of serum alpha-fetoprotein in HBsAg+ and HBsAg- patients in the diagnosis of hepatocellular carcinoma.

Serum alpha-fetoprotein level is often elevated in patients with chronic liver disease and patients with hepatocellular carcinoma. One of the most difficult problems frequently encountered in practice is differentiating hepatocellular carcinoma from chronic liver disease. This study investigated the specificity and predictive value positive of serum alpha-fetoprotein at various levels in the diagnosis of hepatocellular carcinoma, using 54 patients with histologically proven hepatocellular carcinoma and 200 patients with chronic liver disease (40 patients with chronic active hepatitis and 160 patients with cirrhosis) as nontumor controls. Among 254 patients, 170 (66.9%) were HBsAg+. A wide range of overlap (from 0 to 6,400 ng/ml) in the distribution of serum alpha-fetoprotein levels between hepatocellular carcinoma and chronic liver disease patients was observed mainly among HBsAg+ patients. In contrast, the overlapping range of serum alpha-fetoprotein levels between HBsAg- patients with hepatocellular carcinoma and chronic liver disease was remarkably narrow (from 0 to 200 ng/ml). Therefore the specificity and predictive value positive of alpha-fetoprotein at a given level were significantly lower in HBsAg+ than in HBsAg- patients, especially when alpha-fetoprotein was between 25 and 200 ng/ml. The specificities of alpha-fetoprotein at 200 ng/ml and 400 ng/ml in HBsAg+ patients were 79.8% and 91.5%, respectively, whereas these specificities were both 100% in HBsAg- patients. The predictive values positive at 200 ng/ml and 400 ng/ml in HBsAg+ patients were 53.6% and 72.5%, respectively, in contrast to 100% at both levels in HBsAg- patients. The serum alpha-fetoprotein level, which showed a predictive value positive of 95% in HBsAg+ hepatocellular carcinoma patients, was 3,200 ng/ml, whereas that in HBsAg- hepatocellular carcinoma patients, was 200 ng/ml. We conclude that serum HBsAg status should be considered when serum alpha-fetoprotein is measured as an independent test to diagnose hepatocellular carcinoma, and suggest that regular serum alpha-fetoprotein determination may be more useful in HBsAg- patients with chronic liver disease for the early diagnosis of hepatocellular carcinoma than in HBsAg+ patients.

Carcinoma, Hepatocellular↗

PubMed1991

Intraoperative sonography of hepatocellular carcinoma: detection of lesions and validity in surgical resection.

Eighty-six hepatocellular carcinomas (HCCs) in 67 patients were examined by intraoperative sonography. Sensitivity for detecting tumors with intraoperative sonography was compared with sonography, computed tomography (CT), hepatic angiography, and CT after intraarterial injection of iodized poppy-seed oil (Lipiodol-CT). The overall sensitivities were 76% with sonography, 86% with CT, 89% with angiography, 96% with Lipiodol-CT, and 98% with intraoperative sonography. The differences in sensitivity between intraoperative sonography and sonography (p less than 0.01), CT (p less than 0.01), and angiography (p less than 0.05) were significant. In 35 lesions smaller than 2 cm, the sensitivities of Lipiodol-CT and intraoperative sonography were high (91 and 94%, respectively). In operating field, tumors were invisible in 36 (42%) and nonpalpable in 31 of 86 cases (36%). In 35 tumors smaller than 2 cm, invisible tumors were 66% and nonpalpable tumors were 63%. However, 84 of 86 cases (98%) could be localized with intraoperative sonography. These results suggest that intraoperative sonography is the final diagnostic imaging procedure before surgical resection of tumors and in cases of invisible and nonpalpable tumors in the operating field, this procedure is mandatory to improve surgical results.

Carcinoma, Hepatocellular↗

PubMed1991

Elongation and termination reactions of protein synthesis on maize root tip polyribosomes studied in a homologous cell-free system.

We show that the control of gene expression at the level of elongation and termination of protein synthesis can be observed in vitro. Free cytoplasmic polyribosomes were isolated from maize (Zea mays) root tips, and translated in root tip extracts that had been fractionated with ammonium sulfate to contain elongation factors, and be depleted in initiation factors. The root tip extract performs elongation and termination reactions as efficiently as wheat germ extracts. The translation products of the maize system are the same as made in vivo. The dependence of these in vitro elongation and termination reactions on pH was determined. Total protein synthesis in this system exhibits an optimum at pH approximately 7.5. However, the pH dependence of rates of synthesis of individual proteins is not at all uniform; many polyribosomes become stalled when translated at low pH. These data were compared with the elongation and termination capacity of polyribosomes isolated from oxygenated and hypoxic root tips (tissue having, respectively, high and low cytoplasmic pH values). We observed an inverse relationship between the relative abundance of many specific translatable mRNAs in polyribosomes of hypoxic root tips, and the relative rates of elongation and termination reactions on the different mRNAs at low pH in vitro. These results suggest that changes in intracellular pH in hypoxic root tips can be sensed directly by the translational machinery and thereby selectively modulate gene expression.

Journal Article↗

PubMed1991

Atypical clinical manifestations of amebic colitis.

Amebic colitis is a disease revealing diverse clinical manifestations and endoscopic gross features and often confused with other types of colitis. In case of misdiagnosis as an idiopathic inflammatory bowel disease or delayed recognition of intestinal amebiasis, an undesirable outcome may occur resulting from erroneous administration of steroids or delayed antiamebic treatment. To demonstrate the pitfalls in the diagnosis and treatment of intestinal amebiasis, 3 cases of amebic colitis with atypical clinical manifestations are presented in this paper. In conclusion, despite the low sensitivities of routine stool examination for parasite and histopathologic confirmation in biopsy specimen, every effort must be made to find amebic trophozoites either in fresh stool or biopsy specimens for prompt and correct diagnosis of amebic colitis when we manage patients with chronic intestinal ulcerations, even though their clinical course and endoscopic findings are not typical of amebiasis. Moreover, following initial successful anti-amebic therapy, more careful clinical, endoscopical, and parasitological follow-up should be done for the early detection of recurrence.

Adult↗

PubMed1991

Temporal changes in the clinical type or diagnosis of Behçet's colitis in patients with aphthoid or punched-out colonic ulcerations.

The intestinal lesion of Behçet's colitis shows aphthoid or punched-out ulceration. However, the diagnosis of Behçet's colitis should be based on the presence of other stigmata of Behçet's syndrome, since these morphological characteristics are not pathognomonic by themselves. Furthermore, the stigmata of Behçet's syndrome could appear simultaneously or separately with intervals of several months to years. Besides, when a physician first meets patients with intestinal ulcerations of aphthoid or punched-out shape, if they do not have any stigma of Behçet's syndrome, the physician has some difficulty in making a diagnosis of Behçet's colitis. The purpose of this retrospective study was to investigate the followings: 1) The upgrade in clinical type of Behçet's colitis with the advance of time. 2) What portion of the patients with aphthoid or punched-out ulcerations, but without any other clinical feature of Behçet's syndrome, could be diagnosed as Behçet's colitis with the advance of time? During the mean follow-up period of 38.2 months, 4 (22.2%) out of 18 patients with Behçet's colitis upgraded their clinical types. In the nonspecific ileocolitis group, who had no major stigma of Behçet's syndrome on their initial visit, 3 (30%) out of 10 patients were subsequently diagnosed as Behçet's colitis during the mean follow-up period of 33.3 months. From these results, we could conclude that in possible or suspicious cases of Behçet's colitis, a more confident diagnosis could be made by close observations for new developments of major stigma of Behçet's syndrome. Even in cases of nonspecific ileocolitis, the diagnosis of Behçet's colitis could be made in a significant number of cases as time goes by.

Adolescent↗

PubMed1991

A reconstructed cohort study on the hepatitis B virus infection as a risk factor of liver cancer in Korea.

A stable cohort (n = 369,725) was reconstructed to test the association of hepatitis B virus (HBV) infection with subsequent occurrence of liver cancer in a healthy Korean population. The cohort consisted of male beneficiaries of the Korea Medical Insurance Corporation over 30 years of age, living nationwide. The HBV infection was tested by the reversed passive hemagglutination method for the HBsAg and by the passive hemagglutination method for the anti-HBs at the time of recruitment in 1984. Admissions due to liver diseases were identified through a computerized system for reimbursements on medical insurance claims from January 1, 1985 to December 31, 1987. For a more valid estimate of incidence, a sample survey was carried out, obtaining correction coefficients against misclassification of the diagnosis, as well as those for duplicate claims in a year. The incidence rate of liver cancer steadily increased with age (kappa 2 TREND = 51.1, df = 1, p = 0.00).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Inhibition of ammonia monooxygenase in Nitrosomonas europaea by carbon disulfide.

Carbon disulfide has long been recognized as a potent inhibitor of nitrification, and it is the likely active component in several nitrification inhibitors suitable for field use. The effects of this compound on Nitrosomonas europaea have been investigated, and the site of action has been determined. Low concentrations of CS2 (less than 400 microM) produced a time-dependent inhibition of ammonia-dependent O2 uptake but did not inhibit hydrazine-oxidizing activity. CS2 also produced distinct changes in difference spectra of whole cells. These results suggest that ammonia monooxygenase (AMO) is the site of action of CS2. Unlike the case for thiourea and acetylene, saturating concentrations of CS2 did not fully inhibit AMO, and the inhibition resulted in a low but significant rate of ammonia-dependent O2 uptake. The effects of CS2 were not competitive with respect to ammonia concentration, and the inhibition by CS2 did not require the turnover of AMO to take effect. The ability of CS2-treated cells to incorporate [14C]acetylene into the 28-kilodalton polypeptide of AMO was used to demonstrate that the effects of CS2 are compatible with a mode of action which involves a reduction of the rate of turnover of AMO without effects on the catalytic mechanism. It is proposed that CS2 may act on AMO by reversibly reacting with a suitable nucleophilic amino acid in close proximity to the active site copper.

Acetylene↗

PubMed1990

Polymorphic reticulosis with colonic lesion--a case report.

A 38-year-old man was admitted with a high fever, sore throat, and right upper quadrant pain. Nine months before his admission, he had undergone right hemicolectomy under the impression of intestinal lymphoma. But there had been no evidence of lymphoma on microscopic examination. Under the postoperative diagnosis of inflammatory bowel disease, corticosteroid therapy was tried without response. On the follow-up colonoscopic examination, an ovoid ulcer, with convergence of the surrounding mucosal folds at the descending colon and an irregularly shaped ulcer at the ileocolic anastomotic site, were found. The colonoscopic diagnosis was Behcet's colitis. After pathologic slides of biopsy and surgical specimens obtained from the palatine tonsil and colon were reviewed, the diagnosis of polymorphic reticulosis was made. The patient received anticancer chemotherapy, including cyclophophamide and glucocorticosteroid. To date, colonic involvement of polymorphic reticulosis has not been reported. Because of the similarity of the colonoscopic findings to those of Behcet's colitis, polymorphic reticulosis should be included in the differential diagnosis of inflammatory bowel disease. We assume that this is the first case of polymorphic reticulosis involving the colon with characteristic colonoscopic findings.

Adult↗

PubMed1990

Identification of integrated hepatitis B virus DNA sequences in human hepatocellular carcinomas in Korea.

The rate of HBV DNA integration into the genome of hepatocellular carcinoma (HCC) cells varies greatly among HCC tissues from different geographical districts. Because of the potential etiological significance of identifying HBV DNA integration in HCC tissues from Korea, we investigated 13 aseptically obtained HCC surgical specimens by Southern blot analysis. Among 13 HCCs, eight (61.5%) contained integrated HBV DNA. Of eight HBsAg-positive patients, six (75%) had integrated HBV DNA in their HCCs while two (40%) out of five HBsAg-negative patients had integrated HBV DNA. Those two HBsAg-negative patients with integrated HBV DNA were all anti-HBs-positive. However, it was not demonstrated in the patient without any HBV serological markers. These findings highly suggest a prominent etiologic role of HBV in the development of HCC. On the other hand, it also strongly favors a multifactorial etiology of human HCC in korea.

Adult↗

PubMed1990

Etiology and outcome of acute viral hepatitis in Korean adults.

One hundred and sixteen Korean adults with biopsy-proven acute viral hepatitis were studied to determine the etiology and the outcome of the disease using paired sera obtained during acute and convalescent phases. The prevalence of acute viral hepatitis A, B, D and non-A non-B were 3.4%, 60.3%, 0.9% and 35.3%, respectively: hepatitis B virus infection was the most common cause and the hepatitis D virus superinfection was almost negligible. Only eleven (26.8%) of 41 patients with AVH NANB were negative for all serological markers of HBV. The rest (73.2%) were positive for at least one HBV marker: HBsAg was positive in 31.7%. Therefore, the presence of HBV serologic markers in the sera does not exclude the diagnosis of AVH NANB in Korea. In patients with acute viral hepatitis B, 27% remained positive for HBsAg. Chronic hepatitis developed in 12.8% and 17% patients with acute hepatitis B and non-A non-B, respectively. Progression to chronic hepatitis in patients with acute viral hepatitis B and non-A non-B occurred more commonly, although statistically not significant, in male sex and in patients who did not have clinical jaundice during the acute phase and who showed bridging necrosis in their liver biopsies. Age did not influence the progression to chronic hepatitis.

Acute Disease↗

PubMed1990

Incidence rate of hepatitis B: results of a record linkage study among healthy Korean males.

A stable, liver disease-free cohort of 369,725 was reconstructed as of 1984 for the study of hepatitis B virus seromarkers and liver diseases. The cohort consisted of male beneficiaries of the Korea Medical Insurance Corporation (KMIC) over 30 years of age and living nationwide. Subjects who were both negatives for HBsAg and anti-HBs (N = 274,037) were selected for incidence of hepatitis B. Data on test results of HBsAg and anti-HBs in 1984 and on hepatitis B occurrence during 1985-1986 were collected from the files of the KMIC. Linkage was done between these two data sets to measure the incidence rate through a longitudinal observation of the male population. Correction against misclassification error and duplicate claims was done by a sample survey and verification procedures. The incidence rate of hepatitis B was 17.13 per 100,000 person-years for acute viral hepatitis B and 15.74 for chronic hepatitis B, respectively. An increasing age-dependent pattern for acute hepatitis B was not so prominent in this population. However, the incidence rate of chronic hepatitis B steadily increased with age. The relative risk, estimated by a log-linear model for rate and constant hazard, was significantly higher in the over-60 age group than in the others. The incidence rate in the lower socioeconomic class was higher than in the others, although statistically not significant.

Adult↗

PubMed1990

Natural killer and lymphokine-activated killer activities in stomach cancer patients with special emphasis on the effect of 5-fluorouracil, adriamycin and mitomycin-C chemotherapy.

The cytotoxicities of peripheral blood lymphocytes (PBL) and lymphokine-activated killer (LAK) cells were studied to evaluate the effect of chemotherapy on cellular immunity, in 18 patients with unresectable stomach cancer before and after chemotherapy with 5-fluorouracil, adriamycin and mitomycin-C (FAM), and in 21 healthy volunteers. LAK cells were generated in vitro by culturing PBL with 100 U recombinant human interleukin-2 (rH-IL-2)/ml for 72 h. K562 (human myelogenous leukemia), MKN-45 (human stomach adenocarcinoma) and PC-14 (human pulmonary adenocarcinoma) were used as target cells. The cytotoxicity of PBL to K562 and MKN-45 was suppressed in patients with stomach cancer before chemotherapy, compared with that in healthy volunteers (P less than 0.05). The cytotoxicity of LAK cells was significantly higher to all three cell lines tested than that of PBL in both the healthy volunteers and stomach cancer patients (P less than 0.01); however, a lower level of LAK activity was generated in patients with cancer compared to that in the healthy volunteers. FAM therapy did not suppress the cytotoxicities of PBL and LAK cells. The surface markers of PBL and LAK cells were measured, demonstrating that there was no significant change in the percentage of lymphocytes with CD3+, CD4+, CD8+, CD16+ or CD19+ after chemotherapy. The ratios of CD4+ to CD8+ cells in PBL and LAK cells were also not significantly changed after chemotherapy. In the present study, we have demonstrated that the PBL of stomach cancer were defective in generating LAK activity compared to those of controls, but the LAK activity generated from PBL receiving chemotherapy was similar to that from PBL without chemotherapy in stomach cancer patients.

Adult↗

PubMed1989

Studies on avian erythrocyte metabolism. XVII. Kinetics and transport properties of myo-inositol in chicken reticulocytes.

The uptake of myo-inositol was determined in a reticulocyte-enriched fraction prepared from chicken blood and compared with uptake in mature erythrocytes. While reticulocytes accumulated inositol at levels more than threefold that of the plasma concentration, erythrocyte levels were only slightly higher than that of the plasma concentration. The rate of uptake in reticulocytes was approximately 66 mumol/ml rbc/h compared to 5 mumol/ml rbc/h in mature erythrocytes when measured at an inositol medium concentration of 250 microM. The kinetic analysis of inositol influx by reticulocytes reveals a two component system: saturable and nonsaturable. The saturable component, which has a Km for inositol of approximately 222 microM, is Na-dependent. This Na-dependent saturable component, which presumably reflects active transport of inositol, accounts for 30-35% of the transport process. The saturable component is completely inhibited by amiloride but to a lesser extent by ouabain and bumetanide. Moreover, in the course of reticulocyte maturation, the saturable component is lost concomitantly with the completion of the synthesis of myo-inositol pentakisphosphate and the drastic decrease in the membrane permeability to inositol. In addition, phloretin and cytochalasin B, which bind to hexose carriers and inhibit hexose sugar transport, also inhibited inositol transport. The uptake of inositol was not affected by excesses of 3-O-methylglucose (100 mM) or by physiological concentrations of D-glucose. Thus, the transport mechanism of myo-inositol appears distinct from that of D-glucose.

Animals↗

PubMed1989

Preliminary crystallographic analysis of a plant pathogenic factor: pectate lyase.

Pectate lyase is a saccharide-binding enzyme that lyitically depolymerizes polypectate in higher plant cell walls, thus causing soft-rot diseases in food crops. A pectate lyase from Erwinia chrysanthemi, EC16 (PLe), crystallizes in the orthorhombic space group P2(1)2(1)2(1) with unit cell dimension of a = 39.0 A, b = 91.0 A and c = 103.4 A. The asymmetric unit consists of one molecule with a molecular mass of 38,118 daltons and the X-ray diffraction extends to a resolution of 1.8 A. The crystals reproducibly grow to large dimensions and are suitable for a high-resolution X-ray diffraction analysis.

Plant Proteins↗

PubMed1989

Increased serum ferritin in chronic liver disease: a risk factor for primary hepatocellular carcinoma.

Previous studies from this laboratory support the view that increased serum ferritin levels are associated with an increased risk of primary hepatocellular carcinoma (PHC). We have tested this hypothesis in a population of Korean patients with chronic liver disease followed for development of PHC. Serum ferritin levels were measured over time in 249 patients with liver diseases (mostly chronic) followed for 2 to 17 years in Seoul, Korea. Most of the patients were chronically infected with hepatitis B virus. During the first 8 months of follow-up, there were no cases of PHC and no deaths. During this same period, no patient had a serum ferritin level initially below 300 ng/ml and rising above 300 ng/ml, but some patients with ferritin levels above 300 ng/ml experienced decreases to below 300 ng/ml. Therefore, patients were grouped by ferritin level during the first 8 months of follow-up into 3 categories according to the above criteria. Multivariate analysis showed that consistently elevated ferritin levels (category 3) were significantly associated with the development of PHC. Men were more likely to have elevated ferritin levels than women and were at higher risk of developing PHC. Men who were chronically infected with HBV and had ferritin levels above 300 ng/ml had a 50% chance of developing PHC during the follow-up period, compared with a 20% risk of PHC for men with lower ferritin levels (categories 1 and 2). This elevated risk of PHC in men with elevated ferritin levels was confined to the first 3 years of follow-up.

Adult↗

PubMed1989

Sonographic characteristics of small hepatocellular carcinoma.

Fifty-four lesions of small hepatocellular carcinoma under 5 cm in diameter detected by real-time sonography were reviewed to characterize the sonographic feature. Twenty-nine lesions were smaller than 3 cm in diameter and 25 were between 3 and 5 cm in diameter. Sonographic characteristics of hepatocellular carcinoma were peripheral hypoechoic halo (52%), lateral shadow (26%), posterior acoustic enhancement (44%), and mosaic pattern (24%) of the mass. Small tumors less than 3 cm in diameter showed a hypoechoic pattern in half of the cases, whereas most of the tumors between 3 and 5 cm in diameter showed a hyperechoic or mixed pattern. Posterior acoustic enhancement was commonly seen in small tumors less than 3 cm in diameter, while a mosaic pattern was commonly seen in large tumors between 3 and 5 cm in diameter. These results suggest that sonography might be useful for the characterization of small hepatocellular carcinoma.

Adult↗

PubMed1989

Enhancement of cytotoxicity of cisplatin in vitro by recombinant human tumor necrosis factor and/or recombinant human interferon-alpha, -beta and -gamma.

This study was conducted to investigate the modulatory effects of recombinant human tumor necrosis factor (rH-TNF) and recombinant human interferon (rH-IFN)-alpha, -beta and -gamma, either alone or in combination, on the cytotoxicity of cisplatin, using MTT assay, against MKN-45 (human stomach adenocarcinoma). MKN-45 was resistant to rH-TNF even at doses up to 10(3) U/ml. rH-IFN-gamma inhibited the survival of MKN-45 dose-dependently, while rH-IFN-alpha and -beta did not inhibit the survival of MKN-45 even at the highest concentrations tested (10(4) U/ml). Combination of rH-TNF with rH-IFN-alpha, -beta or -gamma did not significantly inhibit the survival of MKN-45, except for a combination of 10 U/ml of rH-TNF and 10(3) U/ml of rH-IFN-gamma (P less than 0.05). Cisplatin inhibited the survival of MKN-45 dose-dependently. By the simultaneous combination of cisplatin with rH-TNF and/or rH-IFN-alpha, -beta or -gamma, cytotoxicity of cisplatin was enhanced and the combination effects were additive. The effects of rH-TNF and rH-IFN-alpha, -beta and -gamma on the modification of cytotoxicity of cisplatin were evaluated in terms of modification index (MI), demonstrating that rH-TNF, rH-IFN-alpha, -beta and -gamma all augmented the cytotoxicity of cisplatin: MI values at 10(3) U/ml of rH-IFN-alpha, -beta and -gamma were 1.4, 1.4 and 2.3, respectively; those at the same concentrations of rH-IFN-alpha, -beta and -gamma in the presence of 10 U/ml of rH-TNF were 3.6, 2.5 and 5.1, respectively. These results demonstrating that the cytotoxicity of cisplatin was enhanced by rH-TNF and/or rH-IFN-alpha, -beta or -gamma suggest that cancer may be more effectively treated with the combination of cisplatin with these biological response modifiers than with cisplatin alone.

Adenocarcinoma↗

PubMed1989

Automation of protein crystallization trials: use of a robot to deliver reagents to a novel multi-chamber vapor diffusion plate.

We report here the automation of search procedures to rapidly screen a large number of reagents and incubation conditions that lead to the formation of protein crystals. The system consists of a Biomek 1000 Automated Laboratory Workstation from Beckman Instruments under the control of a custom user-interface program developed by Cryschem. A plate composed of twenty-four vapor diffusion chambers, each with its own reservoir well and protein drop holder was designed by Cryschem to fit the Biomek table. The Cryschem software manages a large data base of incubation conditions and generates instructions for the workstation to dispense the protein, buffers, detergents, cofactors and other reagents used to promote the formation of protein crystals. The plate is manually positioned on the Biomek table and then under program control additions are automatically made to each chamber as follows: Precipitating solution is added to each reservoir well and the protein solution along with the precipitating solution and various other reagents are added to each drop holder. The plate is removed from the table and a mylar tape is applied to simultaneously seal all the chambers. The plates are placed at a controlled temperature and periodically examined for crystal formation.

Biotechnology↗