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Biomedical subjects

K H Yoon

Publications and source records attributed to K H Yoon.

At least 55 records · Page 3Linked to original sources
PubMed1997

Porcine neonatal pancreatic cell clusters (NPCCs): a potential source of tissue for islet transplantation.

This is a short review of porcine neonatal pancreatic cell clusters (NPCCs) which might eventually be useful for beta cell replacement therapy in people with diabetes. The current success with islet allograft transplantation is reviewed and is problematic because only partial success has been obtained and the shortage of human islet tissue means that only a small fraction of people with diabetes would be able to benefit. For these reasons there is considerable interest in xenotransplantation, with pigs being a particularly attractive source. The relative merits of early fetal, late fetal, neonatal and adult porcine tissue are discussed. Neonatal tissue has several attractive features, with their hardiness and potential for growth being especially noteworthy. NPCCs are harvested after digested and dispersed clumps of cells are kept in culture for 7 days. The NPCCs consist mainly of duct cells, protodifferentiated cells and mature endocrine cells. The protodifferentiated cells are either double or triple stained for insulin, cytokeratin 7, glucagon, pancreatic polypeptide, or somatostatin. When transplanted into diabetic nude mice it usually takes weeks before glucose levels are normalized, and during that time differentiation and growth of the graft can be observed. Potential strategies for controlling xenograft rejection are mentioned, with these being immunosuppression, induction of tolerance, immunobarrier devices, and gene transfer approaches.

Animals↗
PubMed1995

Antibacterial substance produced by Streptococcus faecium under anaerobic culture.

A facultative anaerobe isolated from Korean domestic soil produced an antibacterial substance under strict anaerobic conditions. Based on the morphological and biochemical tests, and cellular fatty acid profiles, the anaerobe was identified as Streptococcus faecium. An antimicrobial compound produced from the S. faecium was identified as 3,7,12-trihydroxy-24-cholanic acid methylester on the basis of its physico-chemical analysis. This substance had potent antibacterial activities against a test organism harboring multiple antibiotic resistance markers, and a variety of pathogenic bacteria. The isolated S. faecium produced lactic acid as well as the antibiotic compound under the anaerobic conditions.

Anaerobiosis↗
PubMed1995

A case of alopecia universalis without the involvement of scalp hairs.

A case of alopecia universalis in a 45-year-old male was reported. The hair loss initiated on the eyebrows and progressed to the whole body, but the scalp hairs were well preserved. Histopathologic features of eyebrows were compatible findings with alopecia areata. This is a unique case of alopecia universalis without any involvement of scalp hairs.

Alopecia↗
PubMed1994

Nucleotide sequence of the gene encoding the Corynebacterium glutamicum mannose enzyme II and analyses of the deduced protein sequence.

The complete nucleotide sequence of the gene encoding the Corynebacterium glutamicum mannose enzyme II (EIIMan) was determined. The gene consisted of 2052 base pairs encoding a protein of 683 amino acid residues; the molecular mass of the protein subunit was calculated to be 72570 Da. The N-terminal hydrophilic domain of EIIMan showed 39.7% homology with a C-terminal hydrophilic domain of Escherichia coli glucose-specific enzyme II (EIIGlc). Similar homology was shown between the C-terminal sequence of EIIMan and the E. coli glucose-specific enzyme III (EIIIGlc), or the EIII-like domain of Streptococcus mutans sucrose-specific enzyme II. Sequence comparison with other EIIs showed that EIIMan contained residues His-602 and Cys-28 which were homologous to the potential phosphorylation sites of EIIIGlc, or EIII-like domains, and hydrophilic domains (IIB) of several EIIs, respectively.

Amino Acid Sequence↗
PubMed1993

Evaluation of polymerase chain reaction amplification of Mycobacterium leprae-specific repetitive sequence in biopsy specimens from leprosy patients.

Biopsy specimens were obtained from 102 leprosy patients before chemotherapy and examined by polymerase chain reaction (PCR) using the primers amplifying the 372-bp DNA of a repetitive sequence of Mycobacterium leprae. The PCR results were then compared with bacterial indices (BI) of slit-skin smears and biopsy specimens. The intensities of DNA bands were in general correlated with the numbers of acid-fast bacilli, and even a sample with only one organism gave a PCR positive result. Ten 5-micron sections from each frozen tissue sample were pooled and processed for DNA preparation. PCR was positive for 11 (73.3%) of 15 biopsy specimens with BI of 0 determined for the paraffin sections from the same biopsy samples. PCR also gave positive results for 84 (96.6%) of 87 BI positive biopsy samples. Although the difference in overall results between the two methods was not statistically significant, PCR seemed to have an advantage over microscopic examination in detecting M. leprae in biopsy specimens negative for acid-fast bacilli. Further evaluation of PCR using more specimens from leprosy patients who are bacteriologically negative is warranted to ensure PCR's advantage over the conventional microscopic examination for the diagnosis of leprosy.

Base Sequence↗
PubMed1992

Detection of Mycobacterium tuberculosis in clinical samples from patients with tuberculosis or other pulmonary diseases by polymerase chain reaction.

Polymerase chain reaction (PCR) using primers targeting the IS6110 repetitive sequence was employed to detect Mycobacterium tuberculosis in 228 samples from patients with tuberculosis or other pulmonary diseases and controls, and the results were compared with culture and clinical findings. None of culture negative samples from 17 healthy controls were PCR positive. Of 109 active tuberculosis patients under chemotherapy, 88 (80.7%) were PCR positive and were significantly higher than 63 (57.8%) positive by culture. Fifty-nine (93.7) of 63 culture positive and 29 (63.0%) of 46 culture negative specimens contained M. tuberculosis detectable by PCR. In 41 specimens from inactive tuberculosis patients who visited to the chest clinic because of chest problems, 16 (39.0%) also gave PCR positive results. In addition, 14 (46.7%) of 30 specimens submitted for M. tuberculosis culture from patients with pulmonary diseases were PCR positive. Presumptive diagnosis of these PCR positive patients was bronchitis, pneumonia, bronchial asthma, etc. Therefore, this study suggests that PCR is sensitive and specific in detecting M. tuberculosis in clinical specimens. However, the interpretation of the PCR results in specimens from patients with pulmonary diseases should be done cautiously in areas with a high prevalence of tuberculosis.

Base Sequence↗
PubMed1991

Comparison of DNA fragment patterns between the phenolic glycolipid-Tb producers and non-producers of Mycobacterium tuberculosis.

Differences in ability to produce the specific phenolic glycolipid-Tb (PGL-Tb) antigen among Mycobacterium tuberculosis strains have been reported. One of the explanations would be the genotypic variation between the strains. In this study, we compared the DNA fragment patterns after digestion of DNA with various restriction enzymes between the PGL-Tb producing and non-producing strains of M. tuberculosis. Three clinical isolates of M. tuberculosis producing the PGL-Tb antigen detectable by thin-layer chromatography, and M. tuberculosis H37Rv and M. bovis BCG not producing the antigen were grown in Sauton medium. The chromosomal DNA was digested with the restriction endonucleases, Eco RI, Sau3A I, BamH I, Xho I, Sma I, Pst I, Hinc II, and Bst EII. Most of the restriction enzymes used gave no clear DNA bands or no DNA fragment common just to the PGL-Tb producing strains. When DNAs were digested with Bst EII, however, there was a 13 kb DNA fragment common to the PGL-Tb producing isolates of M. tuberculosis and not present in the H37Rv strain and M. bovis BCG. This study thus suggests that there might be differences in DNA fragment patterns between the PLG-Tb producing and non-producing strains of M. tuberculosis.

Antigens, Bacterial↗
PubMed1989

A case of subcutaneous seeding of hepatocellular carcinoma after fine needle aspiration biopsy.

Cancer spread along the needle track following fine needle aspiration biopsy is said to be a rare complication. The authors report a case of subcutaneous implantation of hepatocellular carcinoma following ultrasono-guided fine needle aspiration biopsy. The patient, a 67-year-old Korean male was found to have a large hepatocellular carcinoma diagnosed by fine needle aspiration biopsy. Four months later, the patient felt two subcutaneous growing lumps at the previous aspiration site. The authors confirmed them histologically 11 months after aspiration.

Aged↗
PubMed1985

Interrelationship of some selected nutritional parameters relevant to taste for salt in a group of college-aged women.

Students in a women's college were investigated for taste acuity for salt, discrimination of salt concentrations in food, and anthropometrical (the body mass index, and systolic and diastolic blood pressures) and biochemical nutritional parameters (blood hemoglobin, plasma zinc, plasma copper, plasma vitamin A, plasma retinol-binding protein, urinary sodium, urinary potassium, urinary magnesium, urinary calcium and urinary zinc). Among 95 students who participated in the test for discrimination of salt concentrations, which was repeated 6 times with 5 different test samples, only 43 (45.3%) committed no mistakes. The detection threshold for taste of salt was significantly associated with neither the discriminability of salt concentrations nor any biochemical parameters. Levels of plasma zinc (PZn), urinary zinc (UZn) and plasma vitamin A (VA) were lower in the present subjects than in those reported previously. The rate of correct discrimination (RCD) was significantly correlated with PZn and VA positively, and with urinary sodium (UNa) and urinary potassium (UK) negatively. In the factor analysis to investigate the interrelationship of nutritional parameters, 6 factors with significance were extracted, among which factors 3 and 4 were related to RCD. Factor 3 had large loadings on VA, plasma retinol-binding protein (RBP) and RCD, and factor 4 was positively loaded on UNa and UK and negatively on UZn and RCD. In the stepwise multiple regression analysis (RCD being the dependent variable), significant independent variables selected were VA, UK, PZn, systolic blood pressure and UNa. From these results, the college-aged women's failure in discriminating salt concentrations in food was likely to be related to vitamin A inadequacy, mild Zn deficiency and excessive intakes of Na and K.

Adolescent↗
PubMedDate not supplied

Application of MRI for small intestinal diseases.

Until recently, MRI has not been considered to be suitable for the evaluation of the small intestine due to artifacts associated with bowel peristalsis or respiration. However, recent advances of MR techniques enable the acquisition of clear images of the small intestine. Therefore, the purpose of this article is to review the details for the application of MRI in patients with small intestinal diseases. This article discusses bowel preparation and oral contrast agents as well as MR techniques and pulse sequences. Thereafter, the usefulness of MRI for the lesions in the peritoneal cavity or in the gastrointestinal tract are discussed. Small intestinal lesions are categorized into inflammatory, neoplastic, ischemic, and obstructive bowel diseases. In conclusion, MRI can be used as an alternate modality of choice for imaging various diseases of the small intestine.

Administration, Oral↗
PubMedDate not supplied

Colonic wall thickening in cirrhotic patients: CT features and its clinical significance.

BACKGROUND: To evaluate the computed tomographic (CT) features of colonic wall thickening in cirrhotic patients and to determine their prognostic value. METHODS: We retrospectively reviewed 28 cirrhotic patients with colonic wall thickening (>/=10 mm) on CT. Twenty-six of the 28 patients had hepatocellular carcinoma. The severity of hepatic dysfunction was determined by using the Child-Pugh classification. We analyzed the patterns of bowel wall thickening and degree of portal hypertension on CT and the survival periods after initial CT detection of colonic wall thickening. RESULTS: The involved segment of the colon was diffusely thickened with either scalloped or nodular circumferential configuration. In all patients, the thickened colonic wall enhanced poorly. Although the ascending colon was involved in all patients, the transverse (n = 14) or descending (n = 5) colon was also simultaneously involved. Most patients exhibited an advanced stage of portal hypertension on CT. The median survival period of 25 patients who expired was 34 days, and 21 patients (84%) expired within 3 months. CONCLUSIONS: Colonic wall thickening on CT can be used as one of the indicators of poor prognosis in cirrhotic patients. Advanced liver cirrhosis with significantly severe dysfunction is the likely cause of mortality. Therefore, a less aggressive therapeutic approach is recommended if hepatocellular carcinoma is coexistent in these patients.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Primary malignant fibrous histiocytoma of the liver: imaging features of five surgically confirmed cases.

BACKGROUND: The purpose of the present study was to describe the various imaging features of primary malignant fibrous histiocytoma (MFH) of the liver, a rare tumor of mesenchymal origin. METHODS: Sonography (n = 5), computed tomography (CT; n = 5), magnetic resonance (MR) imaging (n = 2), and hepatic arteriography (n = 3) in five patients who underwent partial hepatectomy for tumor resection were retrospectively reviewed and correlated with pathologic findings. RESULTS: All tumors were clearly demarcated from surrounding hepatic parenchyma in sectional imaging with (n = 2) or without (n = 3) a fibrous capsule, which was pathologically verified. Internal architecture of abundant fibrosis, myxoid degeneration, and/or hemorrhagic necrosis reflected the sonographic, CT and MR imaging findings. Marginal tumor staining without definite tumor vasculature was the main feature of hepatic arteriography. There was no intratumoral calcification. All three tumors involving the right lobe of the liver invaded the right hemidiaphragm. CONCLUSION: Although there were no unique findings of primary hepatic MFH, a combined interpretation of various imaging modalities may elucidate the malignant nature of the tumor.

Adult↗
PubMedDate not supplied

Pseudolesion in segments II and III of the liver on CT during arterial portography caused by aberrant right gastric venous drainage.

We report three cases of pseudolesions caused by aberrant right gastric venous drainage (AGVD) in segment II/III of the liver as demonstrated on CT during arterial portography (CTAP). On CTAP, the lesions were seen as wedge-shaped perfusion defects, and on hepatic arteriography, AGVD directed to the area with the perfusion defect was visible in all three cases. When a perfusion defect is detected at the edge of segments II/III at CTAP, a pseudolesion caused by AGVD should be suspected.

Aged↗
PubMedDate not supplied

CT features of abdominal manifestations of primary antiphospholipid syndrome.

PURPOSE: The purpose of this work was to evaluate the CT features of the abdominal manifestations of primary antiphospholipid syndrome (PAPS). METHOD: Of the 32 patients who were confirmed to have PAPS among 751 patients with elevated antiphospholipid antibodies during a 2 year period, we retrospectively reviewed the 14 patients who underwent abdominal CT. The clinical indications for abdominal CT included abdominal pain, abdominal distension, or lower leg swelling. CT findings were analyzed with regard to the abdominal vascular system and abdominal organ involvement patterns as well as ancillary findings. RESULTS: Of the 14 patients with PAPS, 10 had involvement of the venous system (72%), 2 of the arterial system (14%), and 2 of both systems (14%). Of the 12 patients who had venous system involvement, 4 had thrombosis in the inferior vena cava (IVC), 2 in both the IVC and the hepatic vein, 1 in the IVC and splenic and portal veins, 1 in the IVC and hepatic and adrenal veins, 1 in the hepatic, portal, and renal veins, and 3 in the portal and superior mesenteric veins. Budd-Chiari syndrome developed in five of the nine patients who had thrombosis of the IVC or hepatic vein. Arterial thrombosis was noted in four patients, hepatic artery in two, aorta in one, renal artery in one, pancreatic arcade in one, and splenic artery in one, with infarct of multiple organs including the liver, jejunum, colon, kidney, and adrenal gland. Seven of the 14 patients (50%) manifested thrombosis or infarct of multiple extra-abdominal organs. CONCLUSION: PAPS should be included in the differential diagnosis when CT demonstrates infarcts in multiple organs or patients have recurrent episodes of venous or arterial thrombosis.

Adolescent↗
PubMedDate not supplied

Primary antiphospholipid antibody syndrome and mesangial IgA glomerulonephritis.

The antiphospholipid antibody syndrome (APS) is characterized by recurrent thrombosis, fetal loss, multiorgan involvement, and the presence of lupus anticoagulant and/or anticardiolipin antibody. When not associated with systemic lupus erythematosus, other collagen diseases, or ingestion of medications, the condition is called primary APS. The kidney may be involved in the APS syndrome with acute nephritis and renal failure. The cases with renal biopsy studies have shown variable glomerular morphology, ranging from mild mesangial changes to a diffuse endocapillary proliferative glomerulonephritis. The most frequent lesion is thrombotic microangiopathy or features seen in the hemolytic uremic syndrome. Apart from fibrin thrombus deposition, only a few cases have shown focal and segmental deposits of IgG and/or IgM and/or C3. We describe a patient with primary APS who had thrombosis with lower limb amputation and acute renal failure. The renal biopsy specimen showed a focal proliferative glomerulonephritis with endothelial proliferation and damage, with diffuse heavy mesangial deposits of IgA and fibrinogen. This case with diabetes mellitus, but without diabetic nephropathy, represents the occurrence of primary APS and mesangial IgA nephropathy which potentiated the renal injury, leading to acute renal failure. The relationship to the Henoch-Schönlein syndrome is discussed.

Adult↗
PubMedDate not supplied

Differentiation and expansion of beta cell mass in porcine neonatal pancreatic cell clusters transplanted into nude mice.

Neonatal porcine pancreas has considerable capacity for growth and differentiation, making it an attractive potential source of islet tissue for xenotransplantation. Pancreases from 1-3-day-old newborn pigs were digested with collagenase and cultured for 8 days. The resulting cellular aggregates are called porcine neonatal pancreatic cell clusters (NPCCs). The mean yield of NPCCs from a newborn pig was 28,200 +/- 1700 islet equivalents. Cytokeratin 7 (CK7) was used as a marker for the immunostaining of pancreatic duct cells. In neonatal pancreas, 18% of the insulin-positive cells co-stained for CK7, thus being protodifferentiated. NPCCs also contained protodifferentiated cells; insulin/PP and insulin/somatostatin co-stained cells were more common than insulin/glucagon cells. Between 1 and 8 days of culture, the DNA content of the NPCCs fell to 16% and the insulin content to 33% of the starting value, mainly due to the preferential loss of exocrine cells. Transplantation of 2000 or 4000 NPCCs into diabetic nude mice typically normalized glucose values in 10-20 weeks. Mice with successful grafts had lower fasting blood glucose levels than normal mice and accelerated glucose clearance after an i.p. glucose load. The starting NPCCs consisted of 17% insulin-staining cells, but the grafts of mice with reversed diabetes consisted of 94% beta cells, with some co-stained for CK7, indicating that the grafts still contained immature cells. The mass of insulin-producing cells rose from 0.22 +/- 0.08 mg 1 week after transplantation to 4.34 +/- 0.27 mg in mice sacrificed at 27-35 weeks. In summary, NPCCs contain mostly islet precursor cells, which when transplanted into nude mice undergo striking differentiation and beta cell expansion.

Animals↗