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Biomedical subjects

K I Kim

Publications and source records attributed to K I Kim.

At least 37 records · Page 2Linked to original sources
PubMed2000

TTV positivity and transfusion history in non-B, non-C hepatocellular carcinoma compared with HBV- and HCV-positive cases.

The prevalence of TT virus (TTV) and its rate of transmission through transfusion were investigated to determine its possible hepatocarcinogenic role in non-B, non-C hepatocellular carcinoma (HCC) as compared with that in hepatitis B virus (HBV)- and hepatitis C virus (HCV)-positive HCC. Its transfection route in TTV-positive cases was also studied. Serum was positive for TTV in 77.8% (7/9) of HBV-positive, 36.4% (12/33) of HCV-positive, and 63. 6% (7/11) of non-B, non-C cases of HCC. The rate of transmission through transfusion was 52.4% (11/21) in HBV-positive, 40.1% (61/152) in HCV-positive, 33.3% (2/6) in HBV+HCV-positive, and 40% (8/20) in non-B, non-C HCCs, while it was 48.3% (14/29) in TTV-positive and 39.3% (11/28) in TTV-negative cases. The association between TTV and HCC was limited, and the main route of infection of TTV was not through transfusion.

Adult↗
PubMed1999

Selective degradation of unfolded proteins by the self-compartmentalizing HtrA protease, a periplasmic heat shock protein in Escherichia coli.

HtrA, which has a high molecular mass of about 500 kDa, is a periplasmic heat shock protein whose proteolytic activity is essential for the survival of Escherichia coli at high temperatures. To determine the structural organization of HtrA, we have used electron microscopy and chemical cross-linking analysis. The averaged image of HtrA with end-on orientation revealed a six-membered, ring-shaped structure with a central cavity, and its side-on view showed a two-layered structure. Thus, HtrA behaves as a dodecamer consisting of two stacks of hexameric ring. HtrA can degrade thermally unfolded citrate synthase and malate dehydrogenase but cannot when in their native form. HtrA degraded partially unfolded casein more rapidly upon increasing the incubation temperature. However, it hydrolyzed oxidized insulin B-chain, which is fully unfolded, at nearly the same rate at all of the temperatures tested. HtrA also rapidly degraded reduced insulin B-chain generated by treatment of insulin with dithiothreitol but not A-chain or intact insulin. Moreover, HtrA degraded fully unfolded alpha-lactalbumin, of which all four disulfide bonds were reduced, but not the native alpha-lactalbumin and its unfolded intermediates containing two or three disulfide bonds. These results indicate that unfolding of the protein substrates, such as by exposure to high temperatures or reduction of disulfide bonds, is essential for their access into the inner chamber of the double ring-shaped HtrA, where cleavage of peptide bonds may occur. Thus, HtrA with a self-compartmentalizing structure may play an important role in elimination of unfolded proteins in the periplasm of Escherichia coli.

Amino Acid Sequence↗
PubMed1999

The detection of Epstein-Barr virus in the lesions of salivary glands.

Epstein-Barr virus (EBV) is known in association with lymphoid and epithelial lesion. Because the salivary gland is an organ close to the oropharynx, it has a higher incidence of EBV infection and is a possible route of EBV infection. Formalin-fixed, paraffin embedded tissue sections of 87 cases of salivary gland diseases were used for the study of EBV with PCR, in situ PCR for EBNA-1 (EBV nuclear antigen-1), and immunohistochemistry for LMP-1 (latent membrane protein-1). EBV was detected in 12 cases (13.8%): 7 of nonspecific chronic sialadenitis (21.2%), 4 of Warthin's tumors (30.8%), and one lymphoepithelial carcinoma. EBNA-1 was negative in all the other lesions. EBV DNA was detected in the nucleus of epithelial cells and the surrounding lymphocytes. LMP-1 positivity was found in the cytoplasm of epithelial cells. The results of the present study showed that EBV is implicated in some of the inflammatory and neoplastic lesions of the salivary gland in which the lymphocytes are abundant. However, the pathogenesis and mechanism of immortalization and tumorigenesis of the epithelial cells in the salivary glands remain to be determined.

Epstein-Barr Virus Nuclear Antigens↗
PubMed1999

Effect of site and rate of contrast material injection on pulmonary vascular distention.

RATIONALE AND OBJECTIVES: The authors performed this study to determine if there were differences in vascular caliber measured on angiograms obtained with the injection protocol used for spiral computed tomography (CT) versus that used for pulmonary angiography. MATERIALS AND METHODS: The authors studied seven juvenile anesthetized pigs by using a prospective repeated measures experimental design. All pigs received injections of nonionic contrast material via catheters in the brachial vein, superior vena cava, main pulmonary artery, and left pulmonary artery. Weight-adjusted injection rates and volumes ranged from 0.05 mL/kg/sec (3.5 mL/sec, spiral CT protocol) to 0.56 mL/kg/sec (40 mL/sec, pulmonary angiography protocol). Heart rate and pulmonary artery and systemic artery pressures were recorded. During each injection, identically positioned pulmonary angiograms were obtained at full inspiration. Vessel diameters were measured at identical locations after each injection by two observers. The relationship between vessel diameter and hemodynamic parameters and injection site and rate was assessed with analysis of variance. RESULTS: At suspended full inspiration, no statistically significant difference (P > .05) in vessel diameter or hemodynamic parameters was found between the different injection sites or rates. There was no difference in vascular caliber between systole and diastole. CONCLUSION: The improved detection of subsegmental pulmonary emboli at pulmonary angiography compared with contrast material-enhanced spiral CT is not due to differences in vascular distention.

Angiography↗
PubMed1999

Phylogenetic relationships of Cheju horses to other horse breeds as determined by mtDNA D-loop sequence polymorphism.

Historical records suggest that horses inhabiting the island of Cheju in Korea are descendants of Mongolian horses introduced in 1276. Other studies, however, suggest that horses may have been present on the island prior to the Mongolian introduction. To determine the origin of the Cheju horses we used a phylogenetic analysis of sequences of the mitochondrial DNA (mtDNA) D-loop region, including tRNA Pro and parts of tRNA thr and tRNA Phe sequences (1102-bp excluding the tandem repeat region). Maximum parsimony and neighbor-joining trees were constructed using sequences determined for seven Cheju, four Mongolian, one Przewalskii and two Chinese Yunnan horses, and published sequences for one Swedish and three Thoroughbred horses. Donkey mtDNA was used as an outgroup. We found that the mtDNA D-loop sequence varies considerably within Mongolian, Cheju and Thoroughbred horse breeds, and that Cheju horses clustered with Mongolian horses as well as with horses from other distantly related breeds. On the basis of these findings we propose that horses on Cheju Island are of mixed origin in their maternal lineage, and that horses may have existed and been traded on the island before the Mongolian introduction.

Animals↗
PubMed1999

Inflammatory pseudotumor of the liver in a patient with chronic hepatitis C: difficulty in differentiating it from hepatocellular carcinoma.

A case of an inflammatory pseudotumor of the liver in a 75-year-old female with chronic hepatitis C whose radiologic features simulated that of hepatocellular carcinoma (HCC) is presented. On imaging studies, hypervascularity by CO2 ultrasound (US) angiography, enhancement at an early phase and isodensity at a late phase by incremental dynamic computed tomography (CT), perfusion defect by CT during arteriography (CTAP), and clinical background of hepatitis C virus (HCV) infection strongly suggested HCC. A US-guided needle biopsy revealed a mainly diffuse and polyclonal proliferation of lymphocytes positive for leukocyte common antigen (pan-lymphocyte cells), L-26 (B cell lymphocytes), and UCHL-1 (T cell lymphocytes), negative for both kappa and lambda light chains and sparsely distributed neutrophils and histiocytes. No lymphoid follicles were observed. The liver tissue around this tumor showed chronic hepatitis with mild activity and mild fibrosis. These histopathologic findings suggested that the diagnosis of inflammatory pseudotumor of the liver was tenable. As it is difficult to differentiate between inflammatory pseudotumor of the liver and HCC by imaging studies alone, supplemental biopsy, where possible, should be obtained when diagnostic imaging of tumors suggesting HCC is carried out. We emphasize that histopathology is a true gold standard in the diagnosis of this disease.

Aged↗
PubMed1999

Clinically suspected pulmonary embolism: utility of spiral CT.

PURPOSE: To prospectively determine the utility of contrast material-enhanced spiral computed tomography (CT) in the examination of patients clinically suspected of having pulmonary embolism (PE). MATERIALS AND METHODS: One hundred ten patients clinically suspected of having PE were examined with contrast-enhanced spinal CT and at least one other imaging modality: ventilation-perfusion scintigraphy, Doppler ultrasonography of deep leg veins, or pulmonary angiography. Chart review or telephone contact with the referring clinician was used to evaluate the contribution of spiral CT to the final clinical diagnosis. RESULTS: Spiral CT helped correctly identify 23 of 25 patients with PE (sensitivity, 92%). In 57 (67%) of the 85 patients without PE, spiral CT provided additional information that suggested or confirmed the alternate clinical diagnosis: pneumonia (n = 14), cardiovascular disease (n = 10), pulmonary fibrosis (n = 7), trauma (n = 6), malignancy (n = 5), pleural disease (n = 4), postoperative changes (n = 4), and other (n = 7). In the remaining 28 patients, spiral CT scans were normal (n = 12), failed to produce findings supportive of the final clinical diagnosis (n = 13), or were false-positive for PE (n = 3; specificity, 96%). CONCLUSION: Spiral CT has good sensitivity and specificity for the diagnosis of PE. In the majority of patients who do not have PE, it also provides important ancillary information for the final diagnosis.

Adolescent↗
PubMed1998

A novel family of ubiquitin-specific proteases in chick skeletal muscle with distinct N- and C-terminal extensions.

We have recently identified a cDNA for a ubiquitin-specific protease (UBP), UBP41, that encodes the smallest functional UBP identified to date, using an Escherichia coli-based in vivo screening method. In the present study we isolated highly related cDNAs encoding a new family of UBP enzymes, named UBP46, UBP52 and UBP66. These UBPs have virtually identical catalytic domains spanning the sequence of UBP41 between the active-site Cys and the His box (95% identity). However, they possess distinct N- and/or C-terminal extensions. Moreover, they are more closely related to each other than to any other members of the UBP family. Thus these chick UBPs must define a novel family of de-ubiquitinating enzymes and should represent the first example among the UBP family enzymes, whose multiplicity is achieved by variation in their N- and C-terminal extensions. The chick UBPs were expressed in E. coli, and purified from the cells to apparent homogeneity using 125I-labelled ubiquitin-alphaNH-MHISPPEPESEEEEEHYC as a substrate. Each of the purified UBP46, UBP52 and UBP66 enzymes behaved as proteins of similar sizes under both denaturing and non-denaturing conditions, suggesting that all of them consist of a single polypeptide chain. The UBP enzymes cleaved the C-terminus of the ubiquitin moiety in natural and engineered fusions irrespective of their sizes and thus are active against ubiquitin-beta-galactosidase as well as a ubiquitin C-terminal extension protein of 80 amino acids. All UBPs except UBP66 released free ubiquitin from poly-His-tagged di-ubiquitin. However, the isopeptidase activity for hydrolysing polyubiquitinated lysozyme conjugates was not detected from these UBPs, which makes these UBPs distinct from UBP41. These results suggest that the chick UBPs may play an important role in production of free ubiquitin from linear polyubiquitin chains and of certain ribosomal proteins from ubiquitin fusion proteins.

Amino Acid Sequence↗
PubMed1998

Mutational analysis of the two ATP-binding sites in ClpB, a heat shock protein with protein-activated ATPase activity in Escherichia coli.

The 93 kDa ClpB (ClpB93) is a heat shock protein and has a protein-activated ATPase activity. To define the role of the two ATP-binding sites in ClpB93, site-directed mutagenesis was performed to replace Lys212 or Lys611 with Thr or Glu. All of the mutant proteins hydrolysed ATP at a higher rate than that seen with ClpB93 at ATP concentrations up to 2 mM. However, ClpB93 carrying mutations in both of the ATP-binding sites could not cleave ATP. Thus any of the two ATP-binding sites seems to be capable of supporting the ATPase activity of ClpB93. The ATPase activities of both ClpB93/K212T and ClpB93/K212E were gradually decreased when ATP concentrations were increased above 2 mM, unlike those of ClpB93, ClpB93/K611T and ClpB93/K611E, which showed a typical saturation curve. Furthermore ADP inhibited ATP hydrolysis by ClpB93/K212T and ClpB93/K212E more effectively than that by the latter proteins, suggesting that the mutations in the first ATP-binding site result in an increase in the affinity of ADP for the second site in ClpB93. In addition, all of the purified ClpB93 and its mutant forms behaved as an oligomer of 400-450 kDa on a Sephacryl S-300 gel-filtration column, whether or not ATP was present. Thus the binding of ATP to either of the two sites seems not to be essential for oligomerization of ClpB93. Although a low-copy plasmid carrying clpB93 could rescue the sensitivity of a clpB-null mutant cell at 52 degreesC, none of the plasmids carrying the mutations in the ATP-binding sites could. Furthermore, incubation at 52 degreesC resulted in a gradual loss of the ATPase activity of ClpB93 carrying the mutations in either of the two ATP-binding sites, but not of the parental ClpB93, indicating that the mutant proteins have a greater tendency to denature at this temperature than the parental ClpB93. These results suggest that both of the ATP-binding sites in ClpB have an important role in maintaining the thermotolerance of the protein and hence in the survival of Escherichia coli at high temperatures.

Adenosine Triphosphatases↗
PubMed1998

Pulmonary tuberculosis in five young infants with nursery exposure: clinical, radiographic and CT findings.

Clinical, radiographic (n = 5) and CT findings (n = 4) of five Korean infants ranging in age from 2 to 3 months with confirmed tuberculosis were retrospectively analysed. All of the patients were symptomatic, anergic to tuberculin, and had a positive culture of Mycobacterium tuberculosis in gastric aspirates. The probable source of infection was the hospital in which they were born. CT scans demonstrated hilar and mediastinal lymph node enlargement with central low attenuation and peripheral enhancement in all cases. CT may be useful in diagnosis by demonstrating characteristic adenopathy and disseminated disease in young infants.

Cross Infection↗
PubMed1998

Feeding diets containing high levels of milk products or cellulose decrease urease activity and ammonia production in rat intestine.

Three studies were done to determine the effect of feeding diets containing high levels of a readily fermentable carbohydrate (lactose in milk or yogurt, or pure lactose) or an undigestible, unfermentable diluent (alpha-cellulose) on urease (EC 3.5.1.5) activity and net ammonia production in the rat gastrointestinal (GI) contents. Rats (170-200 g) were fed a control diet or diets containing 55% dried milk or 55% dried yogurt, 25% lactose or 10% alpha-cellulose. Feeding diets containing milk or yogurt decreased urease activity to approximately 11% of the control value in the small intestine (on the basis of grams of collected contents or total contents), and to 50% in the large intestine (only on the basis of grams of collected contents). Feeding the diet containing 25% lactose also decreased urease activity (on the basis of grams of collected contents or total contents) to about 20% of the control value in the small intestine, but not (P > 0.05) in the large intestine. Net ammonia production rate was correlated (r2 = 0.98) with urease activity in the large intestinal contents, and the rate of ammonia production from ureolysis represented about two thirds of the total. Feeding the cellulose diet decreased (P < 0.05) both urease activity and net ammonia production in the large intestine to approximately 30% of the control value. Weights of tissue and contents of the large intestine were much higher (P < 0.01) in rats fed diets containing milk products or lactose than in the control rats, but were not affected by consumption of the cellulose diet. Results of our studies indicate that feeding diets containing high levels of milk products (lactose) or cellulose reduces urease activity and net ammonia production in the rat intestine, and thus may be beneficial for improving animal and human health.

Ammonia↗
PubMed1998

A case of well-differentiated minute hepatocellular carcinoma with extrahepatic metastasis.

A rare case of well-differentiated minute hepatocellular carcinoma (HCC) metastasizing to distant sites in a 77-year-old man with hepatitis C virus (HCV)-related cirrhosis is presented. Ultrasonography (US) disclosed a 9 mm hypoechoic lesion in segment seven (S7) of the liver, although computed tomography (CT), magnetic resonance imaging (MRI) and angiography did not reveal any space-occupying lesion. Ultrasound-guided biopsy showed the histological features of well-differentiated HCC. A plain film of the abdomen and CT revealed osteolytic changes in the sacrum and the lumbar vertebra. Ultrasound-guided biopsy of the sacrum revealed well-to-moderately differentiated HCC metastasizing from the liver. Percutaneous ethanol injection therapy (PEIT) effected complete response and completely eliminated the abnormal findings on US. Three months after PEIT, metastasis to the thoracic vertebra was revealed by CT, despite negative alpha-fetoprotein-mRNA in serum. This is the first report describing a well-differentiated HCC with metastatic potential. Further studies may provide insights into metastasis of well-differentiated HCC.

Aged↗
PubMed1998

Prediction of efficacy of interferon treatment of chronic hepatitis C by multivariate analysis and a new classification.

One hundred and fifteen patients with chronic hepatitis C were administered interferon (IFN) and classed into two groups: (i) complete responders (CR), HCV-RNA continuously negative 1 year after treatment; and (ii) non-responders (NR), positive 1 year after treatment. Multivariate analysis comprised eight variables: age, sex, transfusion history, alanine aminotransferase level, viral genotype, level of viremia, type of IFN, and total amount of IFN. The HCV-RNA level was correlated with complete response (P = 0.0175). Liver biopsy specimens were classified into four grades and stages according to the measure of severity and the extent of fibrosis, respectively. There was no correlation between the efficacy rate and grading. However, in staging there was a difference in the efficacy of IFN between stages 1 or 2, and stage 3 (0.05 < P < 0.1 and 0.01 < P < 0.025, respectively). Of the CR patients, 0% (0/5) were at stage 0 (no fibrosis); 27.5% (22/80) at stage 1 (mild); 42.9% (6/14) at stage 2 (moderate); and 6.3% (1/16) at stage 3 (severe fibrosis). Thus the new classification would be useful in predicting roughly the efficacy of IFN.

Adolescent↗
PubMed1998

Acute pulmonary embolism: ancillary findings at spiral CT.

PURPOSE: To determine the value of parenchymal findings at contrast material-enhanced spiral computed tomography (CT) in patients suspected to have pulmonary embolism (PE). MATERIALS AND METHODS: Eighty-eight patients suspected to have PE underwent contrast-enhanced spiral CT and ventilation-perfusion scintigraphy. Concordance between CT and scintigraphic results was used to diagnose or exclude PE. Pulmonary angiography was attempted in all patients with discordant CT and scintigraphic results or indeterminate scans. Parenchymal CT scans were assessed by two radiologists who were not aware of the diagnosis and who had access only to lung window images. RESULTS: Twenty-six patients had PE; 62 did not. Wedge-shaped pleural-based consolidation was seen in 16 patients with PE (62%) and 17 patients without PE (27%) (P < .05) (sensitivity, 62%; specificity, 73%). Linear bands were seen in 12 patients with PE (46%) and 13 patients without PE (21%) (P < .05) (sensitivity, 46%; specificity, 79%). There was no statistically significant difference in the frequency of non-wedge-shaped consolidation, areas of decreased attenuation, or atelectasis. Central and lower-lobe segmental pulmonary arteries that contained emboli were enlarged (P < .05). CONCLUSION: Parenchymal findings may suggest further investigations when results of spiral CT are inconclusive in diagnosis of PE.

Acute Disease↗
PubMed1998

Massive bleeding from left colonic arteriovenous malformation in a young patient with ventricular septal defect.

Arteriovenous malformation of the gut is well known to have been an important bleeding focus in past ages. We report a young Korean male patient, who had been known to have ventricular septal defect, presenting massive lower gastrointestinal bleeding from an arteriovenous malformation involving a long segment of the left colon. Angiographic, gross and histologic findings are presented and the literature is reviewed.

Adult↗
PubMed1998

Chronic pulmonary coccidioidomycosis: computed tomographic and pathologic findings in 18 patients.

OBJECTIVE: To review the computed tomographic (CT) findings in pathologically proven chronic pulmonary coccidioidomycosis. PATIENTS AND METHOD: The study included 19 pulmonary lesions caused by mycologically and pathologically proven chronic coccidioidomycosis in 18 immunocompetent patients (aged 22 to 75 years, mean 57 years) who had a chest CT scan. Thirteen patients were Canadians who had travelled to an endemic area, and 5 were inhabitants of an endemic area in southern California and Arizona. The CT findings were assessed to determine the type, size, margin, internal architecture and location of parenchymal abnormalities. RESULTS: The CT findings included solitary nodules of 1.0 to 2.0 cm (mean 1.7 cm) in diameter in 17 patients, a focal area of ground-glass attenuation in 1 patient, and focal consolidation in 1 patient. Ten of the nodules had homogeneous attenuation on CT, 2 had central areas of low attenuation, 2 showed cavitation, 2 had foci of calcifications and 1 had bubble lucency. The nodules were located peripherally (in 14 patients) and centrally (in 3 patients). The predominant histologic finding in these nodules was a necrotizing granuloma. Three nodules were surrounded by halos of ground-glass attenuation, which were shown on histologic examination to represent granulomatous inflammation (in 2 cases) and pulmonary hemorrhage due to a pulmonary artery-bronchial fistula (in 1 case). Two nodules had adjacent consolidation, which was due to granulomatous inflammation surrounding a necrotizing granuloma. CONCLUSION: Necrotizing granulomas in chronic coccidioidomycosis appear as a well-defined nodule on CT, while granulomatous inflammation may appear as areas of ground-glass attenuation or consolidation.

Adult↗
PubMed1997

Effect of feeding diets containing an antibiotic, a probiotic, or yucca extract on growth and intestinal urease activity in broiler chicks.

A 6-wk study was conducted to determine the effect of feeding diets containing an antibiotic, a probiotic, or yucca extract on daily gain, feed conversion ratio, and urease activity and ammonia production in intestinal contents of broiler chicks. Four replicates of 10 broiler chicks (average body weight, 48 g) each were assigned to a control or diets containing 0.1% chloroxytetracycline (antibiotic), 0.1% Lactobacillus casei (probiotic), or 0.2% yucca extract. Feeding a diet containing the probiotic significantly (P < 0.05) increased average daily gain during the first 3-wk period compared to the control (30.7 vs 28.7 g). This increase was partly accounted for by increased feed intake. During the first 3 wk, feeding the diet containing probiotic significantly (P < 0.05) decreased urease activity (per gram of collected contents) in small intestinal contents but not in large intestinal contents, compared with the control. Urease activity determined at 6 wk of age was not significantly affected by diet. Our studies indicate that dietary probiotic decreases urease activity in the small intestinal contents of young chicks and thus may be beneficial for improving animal health and growth, especially during early life.

Ammonia↗