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Biomedical subjects

Y J Choi

Publications and source records attributed to Y J Choi.

At least 91 records · Page 5Linked to original sources
PubMed1997

Species identification and molecular characterization of Acanthamoeba isolated from contact lens paraphernalia.

We applied ribosomal RNA gene (rDNA) polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to identify Acanthamoeba isolates from contact lens paraphernalia, and characterized these on the basis of mitochondrial DNA (mtDNA) RFLP and isoenzyme analysis. The 22 Acanthamoeba strains used as reference strains were obtained from the American Type Culture Collection. Twenty-eight isolates were classified into six ribogroups, as follows: Acanthamoeba ribogroup (AcRG) 1 consisted of 18 isolates; AcRG 2, of three, AcRG 3, of three; AcRG 4, of two; AcRG 5, of one, and AcRG 6, of one. AcRG 1, which was the most frequently isolated type, was identified as A. lugdunensis, and AcRG 2 as A. hatchetti. AcRG 4 was identified as A. triangularis, while AcRG 3 and AcRG 5 were closely related to A. triangularis. AcRG 6 was identified as A. castellanii. The mtDNA RFLP patterns and zymograms for five isoenzymes of the isolates belonging to a ribogroup were identical to one another. The mtDNA digestion phenotype and zymogram for acid phosphatase (AcP) of AcRG 1 were identical to those of A. lugdunensis L3a and KA/E2, the type strain and corneal isolates from a Korean keratitis patient, respectively. The mtDNA digestion phenotype and zymogram for AcP of AcRG 6 were identical to those of A. castellanii Castellani and KA/E3, the type strain and another corneal isolate found in Korea, respectively. The mtDNA RFLP and zymogram for AcP of AcRG 2 were very similar to those of A. hatchetti BH-2 and Chang, respectively the type strain and a pathogen. The mtDNA RFLP and zymogram for AcP of AcRG 4 were similar to those of A. triangularis SH621, the type strain. The mtDNA RFLP patterns of AcRG 3 and 5 were unique. These results showed that the riboprints, mtDNA RFLP and zymograms of 22 of 28 Acanthamoeba isolates were the same as or very similar to those of the clinical isolates, which can probably be regarded as keratopathogens. More attention should be paid to the prevention of contamination by Acanthamoeba and to the disinfection of contact lens paraphernalia.

Acanthamoeba↗
PubMed1997

Purely epithelioid malignant peripheral nerve sheath tumor of the vulva.

Primary malignant peripheral nerve sheath tumors(MPNST) of the vulva are extremely rare and most of them are composed of a spindle cell component. A few cases of MPNST containing partially or purely epithelioid cells have been reported. Purely epithelioid MPNST differ from the ordinary epithelioid MPNST due to the absence of a spindle cell component. We present the first case of purely epithelioid MPNST arising in the vulva reviewing in the world literature without definite evidence of von Recklinghausen's disease or nerve involvement. The patient was a 63-year-old woman with a palpable vulvar mass, 6 x 4 x 1.5 cm in dimension, was not encapsulated but well-demarcated, ovoid and rubbery and showed pale yellow, homogeneous, fish-flesh appearance with focal cystic changes on cut surface. The histologic features consisted of solely epithelioid cells which were arranged in tight clusters or cords with solid growing pattern and focally scattered rosette-like structures. According to the immunohistochemical results, most of tumor cells were strongly positive for neuron specific enolase, and some of them were weakly positive for S-100 protein and vimentin. We considered that purely epithelioid MPNST would represent a certain degree of differentiation toward nerve or neuronal cells rather than Schwann cells.

Epithelioid Cells↗
PubMed1997

Acute myopathy induced by colchicine in a cyclosporine-treated renal transplant recipient--a case report and review of the literature.

We report a case of colchicine-induced myopathy related to short-term, customary administration of colchicine. A 49-year-old male was admitted because of muscle weakness and myalgia that had developed 10 days previously. He had received renal transplantation 5 years previously and took cyclosporine as an immunosuppressant. Two weeks before admission, gout was developed and he took colchicine (1.2 mg b.i.d) by himself for three days. Colchicine-induced myopathy was clinically suspected, and colchicine intake was stopped immediately. After that, clinical symptoms gradually improved and serum muscle enzyme returned to normal. In this case, mild renal dysfunction and drug interaction between cyclosporine and colchicine wee suggested to be the precipitating factors of colchicine-induced myopathy.

Colchicine↗
PubMed1997

Mixed hepatoblastoma in an adult--a case report and literature review.

Hepatoblastoma is thought to originate from embryonal hepatic tissue, and most of these tumors occur in children under the age of 2 years. Hepatoblastoma in adults is extremely rare, and the prognosis is much worse than the mixed hepatoblastoma of childhood. We experienced a case of mixed hepatoblastoma in a 51 year old female patient. She had been suffering from a mild pain and a palpable lump in the epigastric area. Serum AFP was 43,850 ng/ml. Computerized tomography and selective abdominal angiography showed a large low-density mass. With a suspicion of hepatocellular carcinoma of the left lobe, a left lateral segmentectomy was performed. The external surface showed a huge protruding mass and the capsule was previously ruptured. On section, the tumor was a 11 x 7 cm sized expanding mass which had a variegated surface composed of yellow-white friable tissue with multifocal hemorrhagic areas. Microscopic examination revealed a tumor consisted of epithelial and mesenchymal elements. The mesenchymal cells were spindle in shape and proliferated over the whole tumor with focal osteosarcomatous differentiation. The epithelial components showed well-differentiated hepatocellular carcinoma-like areas, poorly differentiated acinar or tubular structures.

Female↗
PubMed1996

Purification and properties of human cytosolic folylpoly-gamma-glutamate synthetase and organization, localization, and differential splicing of its gene.

Human cytosolic folylpolyglutamate synthetase (FPGS) was expressed in Escherichia coli and purified to homogeneity. Tetrahydrofolate and dihydrofolate were the most effective substrates, while 5-substituted folates were poor substrates. Most pteroyldiglutamates were better substrates than monoglutamates. The human FPGS gene spans 12 kilobases and contains 15 exons and 14 introns. A single FPGS gene was located to chromosome region 9q34.1. Four exon 1 variants were identified, each of which was spliced to exon 2. The exon 1 variant corresponding to the isolated cDNA contains two ATG codons and multiple transcription start sites in this region generates mitochondrial and cytosolic FPGS (Freemantle, S. J., Taylor, S. M., Krystal, G., and Moran, R. G. (1995) J. Biol. Chem. 270, 9579-9584). Exons 1B and 1C, generated by alternate splicing in intron 1, and exon 1A, which is 5' to exon 1 and may encode an additional mitochondrial isoform, are preceded by a number of potential promoter sites. Chinese hamster ovary cell transfectants expressing FPGS activity in the mitochondria contained normal mitochondrial and low cytosolic folylpolyglutamate pools. Mitochondrial FPGS activity is required for mitochondrial folate accumulation, while cytosolic FPGS activity is needed for establishment of normal cytosolic folate pools. The reconstructed FPGS gene restored normal cytosolic and mitochondrial folate metabolism in hamster cells.

Amino Acid Sequence↗
PubMed1996

Human papilloma virus, vulvar dystrophy, and vulvar carcinoma: differential expression of human papillomavirus and vulvar dystrophy in the presence and absence of squamous cell carcinoma of the vulva.

In situ hybridization (ISH) and polymerase chain reaction (PCR) for several common HPV types were performed on 41 cases of vulvar dystrophy, 19 of which were associated with previous or simultaneous invasive squamous cell carcinoma of the vulva. Three of the 19 cases (16%) of dystrophy associated with cancer were found to contain HPV-16/18 by PCR. In contrast, 12 of the 22 cases (55%) of dystrophy not associated with carcinoma contained HPV-16/18 by PCR (P < 0.01). A control group of 10 vulvar specimens without dystrophy or carcinoma was negative for all HPV types tested. ISH was negative for all HPV types in all 41 cases. The data confirm the association between vulvar carcinoma and hypertrophic/mixed dystrophy, and provide evidence for an association between HPV-16/18 and some cases of vulvar dystrophy. Cases of vulvar dystrophy not associated with HPV-16/18 may be at increased risk for the development of vulvar carcinoma.

Blotting, Southern↗
PubMed1996

Direct application of Etest to gram-positive cocci from blood cultures: quick and reliable minimum inhibitory concentration data.

The Etest was applied directly to 100 Gram-positive bacterial strains from blood cultures to measure their minimum inhibitory concentration (MIC). Results showed 100% concordance of MIC data between a direct Etest method and the standard Etest method for Streptococcus pneumoniae, beta-hemolytic streptococci, and viridans group streptococci. In addition, direct Etest for Staphylococcus aureus, coagulase negative staphylococci, Enterococcus faecium, and Enterococcus faecalis showed 83 to 100% correlation with standard Etests. These data indicate that the Etest is useful to obtain MIC data on Gram-positive cocci (especially streptococci) directly from positive blood cultures. The advantages of a direct Etest are two fold: MIC results can be obtained 24 hours earlier than standard methods and a more representative population of the bacterial isolate is tested.

Anti-Bacterial Agents↗
PubMed1996

Clinical significance of a polymerase chain reaction assay for the detection of Mycobacterium tuberculosis.

Various investigators have reported rapid detection of Mycobacterium tuberculosis (MTB) in clinical samples by polymerase chain reaction (PCR). To improve the specificity and efficiency of PCR, the authors adopted a variety of conditions, then analyzed sputum specimens from 217 patients clinically suspected of having MTB. Sputum samples were sonicated to obtain MTB DNA. The DNA was subjected to PCR using primer sets from the region of 650-900 in MTB. The PCR product was detected by direct gel electrophoresis and Southern blot hybridization using digoxigenin-labeled MTB-specific probe. The results of smears, cultures, and PCR were concordant in 93% (202) of the 217 specimens and discordant in 7% (15). Fifteen of the discordant specimens, all from patients who had received antituberculosis medications for days to months, were PCR positive. Of these, 11 were culture negative and 3 were smear negative. Only one specimen was false negative on PCR. Our results indicate that PCR is the method of choice when clinical suspicion is high, but smears or cultures are negative. When smears are positive, PCR permits rapid distinction between MTB and other mycobacterial infections. Because PCR can detect nonviable MTB DNA, positive PCR should be interpreted in conjunction with clinical information.

Bacteriological Techniques↗
PubMed1996

A partially purified beta-glucosidase from Bifidobacterium adolescentis converts cycasin to a mutagenic compound.

beta-Glucosidase was extracted from sonicated Bifidobacterium adolescentis Int-57 and partially purified by Sepharose CL-6B gel-filtration and DEAE-cellulose ion-exchange chromatography. The partially purified enzyme was confirmed to convert cycasin to a mutagen in the Ames and SOS chromotests. beta-Glucosidase negative strains were unable to activate cycasin mutagenically.

Bifidobacterium↗
PubMed1996

Chronic granulomatous interstitial nephritis: unusual complication of acute pyelonephritis.

We describe an unusual complication of acute pyelonephritis in a 45-year-old diabetic female. She was admitted to our hospital due to fever and flank pain which had developed 10 days earlier. Urinalysis showed many WBC and urine culture revealed Escherichia coli. After adequate antibiotic treatment, clinical symptoms abated but renal failure and leukocyturia persisted. Abdominal CT showed bilateral focal bacterial nephritis and renal biopsy disclosed chronic granulomatous interstitial nephritis. On the 80th hospital day she was discharged with a serum creatinine of 299 mumol/l. In the outpatient clinic, renal dysfunction and leukocyturia persisted up to 1 year. In conclusion, this case raises the possibility of a chronic interstitial process of acute pyelonephritis.

Acute Disease↗
PubMed1996

Hemangiopericytoma of renal sinus expanding to the renal hilum: an unusual presentation causes misinterpretation as transitional cell carcinoma.

We report a case of renal hemangiopericytoma occurring in renal sinus and expanding to the renal hilum. This unusual presentation caused misinterpretation of this tumor as transitional cell carcinoma of the renal pelvis clinically. The patient who was a 30-year-old woman had a relatively well demarcated solid tumor, 8 x 6 cm, in the renal sinus of the left kidney.

Adult↗
PubMed1996

Interphase cytogenetics of non-Hodgkin's lymphoma using non-fluorescent in situ hybridization in paraffin embedded tissue.

Paraffin-embedded tissue samples from 30 cases of non-Hodgkin's lymphoma(NHL) and 10 of reactive hyperplasia, were processed for interphase cytogenetic chromosomal study. We performed non-fluorescent in situ hybridization(NFISH) using the enzymatic method with digoxigenin-labeled DNA centromeric probes for chromosome 7,12,18 and X, and a painting probe for chromosome 18. Chromosomal aberrations were observed in 27(90%) out of 30 cases of NHL. The most commonly observed numerical aberration was extracopy of X chromosome. There were some characteristic aberrations corresponding to each grade and group of NHL by International Working Formulation: In low grade NHL(9 cases), a third were associated with extracopy of chromosome 12, and disomy X was frequently found in small lymphocytic lymphoma(75%). With intermediate grade(16 cases), tetraploidy(25%), translocation of chromosome 18(25%), and extracopy of chromosome 18(19%) were characteristically associated. These results suggest that interphase NFISH is an easily performable method in retrograde cytogenetic study of archival materials. Some specifically correlated chromosomal aberrations corresponding to the histopathologic grades and groups could provide us more valuable information for determining pathologic diagnosis and assessing the clinical outcome of NHL.

Chromosome Aberrations↗
PubMed1996

Changing patterns of autopsy findings among persons with acquired immunodeficiency syndrome in an inner-city population. A 12-year retrospective study.

OBJECTIVE: To determine patterns of autopsy findings among persons with acquired immunodeficiency syndrome (AIDS) during a 12-year period. DESIGN AND SETTING: All 168 autopsies performed on adult AIDS patients at the Bronx-Lebanon Hospital Center in New York City between 1982 and 1993 were analyzed. The Center is a 725-bed, acute-care facility in the south Bronx, which serves a population of approximately half a million people. High poverty levels, tuberculosis and AIDS incidence, and intravenous drug abuse are common in this population. Subjects were predominantly Hispanic and black. MAIN OUTCOME MEASURES: Changes in the frequency of single and multiple opportunistic infections in general and frequencies of specific infections during the 12-year period. RESULTS: Through 1986, 75% of AIDS autopsies demonstrated single infections, particularly Pneumocystis carinii pneumonia. Since 1987, 72% of autopsies demonstrated multiple infections related to P carinii pneumonia, mycobacteriosis, cytomegalovirus, and various fungi. During the last 3 years, the prevalence of mycobacterial infections was higher than in the previous 9 years combined. In contrast, P carinii pneumonia decreased from 52% in 1988 to 14% in 1993. CONCLUSIONS: We note the recent emergence of multiple infections by multiple organisms, a significant decrease in the prevalence of P carinii pneumonia, and a slight increase in mycobacterial tuberculosis. Awareness of these changing patterns of infection may be useful in treating persons with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Penile sensitivity in patients with primary premature ejaculation.

PURPOSE: We investigated penile sensory levels in patients with primary premature ejaculation to determine whether there is an etiological basis for this condition. MATERIALS AND METHODS: Penile biothesiometry was performed in 120 patients with primary premature ejaculation without erectile dysfunction and neurological deficit, and in 66 normal potent male volunteers. Vibratory thresholds were recorded at the glans penis, penile shaft, scrotum and index finger using a biothesiometer. RESULTS: On the glans penis and penile shaft the values in patients with premature ejaculation were significantly less than those in normal potent men (p < 0.001). In normal potent men an age dependency of biothesiometric parameters was noted, with a significant increase in vibratory threshold at the glans penis and penile shaft in older patients. However, in patients with premature ejaculation there were consistently decreased values without age dependency at the glans penis and penile shaft (p > 0.05). CONCLUSIONS: Patients with primary premature ejaculation have penile hypersensitivity, which provides further implications for an organic basis of premature ejaculation.

Adult↗
PubMed1996

Pharmacokinetic changes of M1, M2, M3, and M4 after intravenous administration of a new anthracycline, DA-125, to alloxan-induced diabetes mellitus rats.

The pharmacokinetics of M1, M2, M3, and M4 were compared after intravenous (i.v.) administration of DA-125, 15 mg/kg to the control (n = 15) and alloxan-induced diabetes mellitus (AIDM, n = 11) rats. After i.v. administration of DA-125, almost 'constant' plasma concentrations of M1 and M2 were maintained from 1-2 h onwards to 8-10 h in both groups of rats due to the continuous formation of M2 from M1. The plasma concentrations of M3 were the lowest among M1-M4 in the control rats due to the rapid and essentially complete conversion of M3 to M4. The AUC0-8 h of M1 (189 versus 78.5 mg min/ml) was significantly greater in the AIDM rats than that in the control rats. However, the AUCts of M2 (32.7 versus 44.3 micrograms min/ml) and M4 (not measurable versus 19.7 micrograms min/ml) were significantly smaller in the AIDM rats. The renal clearances of both M1 (0.157 versus 0.334 ml/min/kg) and M2 (0.726 versus 14.6 ml/min/kg) decreased significantly in the AIDM rats, presumably due to their impaired kidney function. The liver weight decreased significantly in the AIDM rats (2.77 versus 3.77% of body weight), suggesting impaired liver function. Above data suggested that the metabolism of M1 to M2-M4 in the liver and kidney decreased significantly in the AIDM rats. M2 was the main metabolite among M1-M4 excreted in 24 h urine in both group of rats. In the AIDM rats, the amount of M2 excreted in 24 h urine decreased significantly (15.7 versus 229 micrograms) whereas the amount of M2 recovered at 24 h from the whole GI tract increased significantly (45.1 versus 14.0 micrograms).

Alloxan↗
PubMed1995

Pre- and post-translational regulation of lysyl oxidase by transforming growth factor-beta 1 in osteoblastic MC3T3-E1 cells.

The final enzymatic step required for collagen cross-linking is the extracellular oxidative deamination of peptidyl-lysine and -hydroxylysine residues by lysyl oxidase. A cross-linked collagenous extracellular matrix is required for bone formation. The goals of this study were to compare the transforming growth factor (TGF)-beta 1 regulation of lysyl oxidase enzyme activity and steady state mRNA levels to changes in COL1A1 mRNA levels in MC3T3-E1 osteoblastic cells. TGF-beta 1 increased steady state lysyl oxidase and COL1A1 mRNA levels in a dose- and time-dependent manner. The increase in lysyl oxidase mRNA levels was transient, peaking at 12 h and 8.8 times controls in cells treated with 400 pM TGF-beta 1. COL1A1 steady state mRNA levels increased maximally to 3.5-fold of controls. Development of increased lysyl oxidase enzyme activity was delayed and was of slightly lower magnitude than the increase in its mRNA levels. This suggested limiting post-translational processing of lysyl oxidase proenzyme. Pulse-labeling/immunoprecipitation studies demonstrated slow proenzyme secretion and proteolytic processing. Development and application of an independent assay for lysyl oxidase proenzyme proteolytic processing activity verified its proportionately lower stimulation by 400 pM TGF-beta 1. Thus, lysyl oxidase regulation by TGF-beta 1 in osteoblastic cell cultures occurs at both pre- and post-translational levels. This regulation is consistent with increased production of a collagenous extracellular matrix.

3T3 Cells↗