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Biomedical subjects

Y S Song

Publications and source records attributed to Y S Song.

54 records · Page 3Linked to original sources
PubMed1998

Postprocess contamination of flexible pouches challenged by in situ immersion biotest.

Packages were evaluated for leaks by determining microbial penetration through microchannels as a function of test organism concentration, location in a retort, and microchannel diameter and length. A flexible pouch was used in an in situ immersion biotest coupled with a state-of-the-art retort. Microchannel diameters of 10 to 661 microm with 3- and 6-mm lengths were created by placing tungsten wires in vacuum heat-sealed flexible pouches. After removing the wires, these pouches were subsequently heat processed under pressure. They were then biotested in cooling water containing 10(3) and 10(6) CFU of motile Enterobacter aerogenes per ml for 30 min and were dried immediately after manual unloading. After incubation at 37 degrees C for 3 days, they were visually examined for contamination. The high-temperature retorting process was shown to decrease microchannel diameters by an average of 20%. Generally, the smaller the microchannel diameter, the greater the percent shrinkage. Statistical analysis of the biotesting data showed that microchannel diameter and length had strong effects on microbial penetration (P < 0.01). Microbial concentration had a borderline significant effect (P < 0.05), but the effect of package location in the retort was not significant. At conservative conditions, such as a 3-mm microchannel length and a cooling water contamination level of 10(6) CFU/ml, the selected microorganism can penetrate microchannels with diameters as small as 7 microm. However, the minimum microchannel diameter for penetration could be as large as 46 microm at practical conditions of 6-mm microchannel length and contamination levels of 10(3) CFU/ml.

Colony Count, Microbial↗
PubMed1997

Major sequence variants in E7 gene of human papillomavirus type 16 from cervical cancerous and noncancerous lesions of Korean women.

Geographic specificity of nucleotide sequence variations in the coding and noncoding regions of HPV 16 genome has been reported. Little has been known, however, regarding whether these naturally occurring sequence variations of HPV 16 may result in marked differences in biological properties, such as oncogenic potential. This study was performed to identify sequence variants in the HPV 16 E7 gene derived from Korean women with cervical cancerous and noncancerous lesions, and to assess the association between the sequence variant and the cervical cancer. We examined E7 variants of HPV 16 in a total of 157 patients with no cervical disease (NCD, n = 87) or cervical neoplasia (cervical intraepithelial neoplasia 3, n = 21; cervical carcinoma, n = 49), using the nested polymerase chain reaction (PCR) and the PCR-directed sequencing methods with outer consensus and inner type-specific primers. Forty-two (NCD, n = 9; CIN 3, n = 6; cervical carcinoma, n = 27) of 157 cervical samples contained HPV 16 E7 DNA, but only 8 had prototype sequences. Four variants of the HPV 16 E7 gene were identified. The variant with a single nucleotide change at position 647 (A --> G, Asn --> Ser) was found in about 60% of DNA samples with HPV 16. The second most common variant, found in 16.7% of cases, had three silent mutations at positions 732 (T --> C), 789 (T --> C), and 795 (T --> G). Two other variants were detected, one in a patient with cervical cancer and the other in a patient with no cervical disease. One had a single nucleotide change at position 666 (G --> A) and the other had one silent mutation at position 796 (T --> C). The most common variant in Korea has a change of nucleotide affecting the predicted amino acid related with high antigenicity and binding to retinoblastoma protein. There was a statistically significant trend for this variant to be more frequently detected in cancerous lesions of the uterine cervix than in noncancerous lesions. These data suggest that naturally occurring sequence variants of HPV 16 E7 gene may have different oncogenic properties.

Adult↗
PubMed1997

Determination of cefuroxim levels in human serum by micellar electrokinetic capillary chromatography with direct sample injection.

Effective monitoring of cefuroxim levels by micellar electrokinetic capillary chromatography with direct serum injection are discussed and compared with the HPLC method. With capillary electrophoresis (CE), in contrast to HPLC, good resolution and efficiency was demonstrated as well as low consumption of solvent and samples. The CE system was applied at 15 kV with UV detection at 274 nm using 150 mM sodium dodecyl sulfate in 20 mM sodium phosphate and borate (pH 9.0) as electrolyte. The results were seen within 12 min with efficiency approaching 182,000 theoretical plates. The coefficients of variations of migration time and peak area were less than 0.8 and 5.9%, respectively. The detection limits for quantitative determination were 0.28 microM level. Good linearity and recovery were also obtained in the range of serum levels usually encountered in clinical analysis with a correlation coefficient of r = 0.991 and 98-101% recovery. The monitoring of cefuroxim in human serum with micellar electrokinetic capillary chromatography (MECC) is demonstrated. Identification of cefuroxim in human serum with MECC is demonstrated. Identification of cefuroxim was performed by characterizing the sample peak in terms of the migration time and UV spectrum. Considering the results of our study, the CE method should by highly suitable for the separation of cefuroxim in biofluids.

Cefuroxime↗
PubMed1997

Risk factors associated with uterine cervical cancer in Korea: a case-control study with special reference to sexual behavior.

OBJECTIVE: A hospital-based case-control study was conducted to identify characteristics of women at high risk of developing cervical cancer with special reference to sexual behavior in Korea. METHODS: Histologically confirmed cases of invasive cervical cancer were selected from the Department of Gynecology, Seoul National University Hospital between September 1992 to May 1995 (n = 203). Women with normal pap smear tests and women free of past history of any malignancies were regarded as controls (n = 827). Information on risk factors were collected by both a self-administered questionnaire and a direct interview. RESULTS: Uterine cervical cancer risk was higher in women with a less educated spouse (Ptrend = 0.0003), women with a family history of cervical cancer (adjusted odds ratio [OR] = 2.20., 95% confidence interval [CI] 1.21-4.01), women of shorter height (Ptrend = 0.02), women with early age at first full term pregnancy (Ptrend = 0.0005), and women who have had multiple full term pregnancies (Ptrend = 0.006) by the multiple linear logistic analysis. Particularly noteworthy was a significant decreasing trend in the adjusted OR with the age at first sexual intercourse increasing (Ptrend = 0.002) after adjusting the number of sexual partners. The husband's indecent sexual history showed a borderline significance (Ptrend = 0.07). CONCLUSIONS: This study confirmed that the risk factors of cervical cancer in Korea are similar with those found in other countries.

Adult↗
PubMed1996

Survey of natural occurrence of trichothecene mycotoxins and zearalenone in Korean cereals harvested in 1992 using gas chromatography/mass spectrometry.

For the survey of the natural occurrence of trichothecene mycotoxins, produced by species of fungi imperfecti such as Fusarium and Trichothecium, a sensitive analytical method was developed for the simultaneous detection and quantitation of the major trichothecene mycotoxins, viz. T-2 toxin (T-2), HT-2 toxin (HT-2), nivalenol (NIV), fusarenon-X (F-X), deoxynivalenol (DON), 3-acetyl deoxynivalenol (3-Ac DON), and zearalenone (ZEN), using gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) mode after trimethyl silyl derivatization. The incidence of NIV and DON in 30 barley samples were 93% and 67%, respectively; the average contents of NIV and DON in positive samples were 390 ng/g (range 40-2038) and 106 ng/g (range 5-361) respectively. In 15 maize samples, the incidences of NIV and DON were 53% and 93% respectively and the average contents were 168 ng/g and 145 ng/g, respectively. These results suggest that NIV and DON were the major contaminating trichothecene mycotoxins in Korean barley and maize samples harvested in 1992.

Edible Grain↗
PubMed1996

Clinical utility of calculated creatinine clearance as a guide to chemotherapy in patients with gynecologic malignancies.

OBJECTIVE: To examine the relationship between calculated and measured creatinine clearance, and also to evaluate the clinical utility of calculated creatinine clearance before administration of chemotherapy in patients with gynecologic malignancies. METHODS: In 38 patients with gynecologic malignancies, a total-69 paired creatinine clearance measured by 24-hour urinary creatinine clearance and calculated were compared. RESULTS: The significant correlation (r = 0.597, p < 0.0001) was observed between creatinine clearances determined by both methods. There were 26 (37.7%) 24-hour urine collections. The correlation between two methods improved when these inaccurate samples were excluded (r = 0.876, p < 0.0001). In addition, if a creatinine clearance of 50 ml/min is set as a threshold for dose modification, only 2.9% of the patients would have received reduced doses inappropriately, by using the calculated creatinine clearance alone. CONCLUSION: These results suggest that in patients with gynecologic malignancies, a calculated creatinine clearance prior to chemotherapy is sufficient for evaluation of renal function and measured creatinine clearance would be determined only when calculated creatinine clearance is below the threshold for dose modification.

Adult↗
PubMed1995

Introduction of wild-type p53 gene downregulates the expression of H-ras gene and suppresses the growth of bladder cancer cells.

Retroviral vectors were used to introduce the wild-type p53 gene into human bladder cancer cell lines BIU-87 and EJ, which express endogenous wt-p53 gene and have a mutation in H-ras gene. The expression of the exogenous wt-p53 gene in cells suppresses the growth of the bladder cancer cells in standard culture and in soft agar and blocks the cell cycle progression in G1. The BIU-87 and EJ cells developed tumors with average volumes of 6.53 cm3 and 6.61 cm3 in nude mice in 9 weeks after inoculation, while the cells transduced with wt-p53 gene failed to form tumors. The expression of H-ras gene in bladder cancer cells was reduced at mRNA level. These results suggest that the overexpression of the wt-p53 gene suppresses the expression of mutant H-ras gene and inhibits the tumor cell growth in vivo and in vitro.

Animals↗
PubMed1994

Metabolism and pharmacokinetics of S-(N,N-diethyldithiocarbamoyl)-N-acetyl-L-cysteine in rats.

The metabolism and pharmacokinetics of a mixed disulfide S-(N,N-diethyldithiocarbamoyl)-N-acetyl-L-cysteine (AC-DDTC) were studied in rats. Two metabolites of AC-DDTC following i.v. and p.o. administration were identified in plasma and liver by HPLC and GC, namely N,N-diethyldithiocarbamate (DDTC) and the methyl ester of DDTC (Me-DDTC). AC-DDTC was very unstable in vivo and could not be detected neither in plasma nor in urine. Pharmacokinetic parameters of DDTC following intravenous administration of AC-DDTC (20 mg/kg) were calculated. DDTC has a low affinity to rat tissue and the total body clearance was 9.0 +/- 3.4 ml/min/kg. The mean residence time (MRT) was 111.5 +/- 16.3 min. After oral administration of 20 mg/kg AC-DDTC, maximal plasma concentration (Cmax) was 3.8 +/- 0.2 nmol/ml and the bioavailability was 7.04%. Cmax for DDTC at a dose of 120 mg/kg AC-DDTC was 40.1 +/- 2.2 nmol/ml. MRT was 47.1 +/- 2.8 min at a dose of 20 mg/kg and 110.5 +/- 6.0 min at 120 mg/kg.

Acetylcysteine↗
PubMed1993

Repair of digital nerve defect with autogenous vein graft during flexor tendon surgery in zone 2.

Autogenous vein graft was used to fill 18 digital nerve defects between 0.5 to 5.8 cm in length during flexor tendon surgery in zone 2. The vein was taken from the forearm and reversed to bridge the digital nerve. For nerves with defects over 2.0 cm, normal nerve slices were inserted inside vein conduits. Recovery of sensibility was evaluated by von Frey test, pin-prick detection, localization of stimulus, moving two-point discrimination and sweating on the finger pulp. Follow-up revealed excellent recovery in two digital nerves, good in nine, fair in five and poor in two. The results suggest that vein graft provides a simple and practical method to reconstruct a digital nerve defect during tendon repair in zone 2.

Adolescent↗
PubMed1992

The effects of probenecid on the excretion kinetics of stanozolol, an anabolic steroid, in rats.

The pharmacokinetic behaviour and the mechanism of renal excretion of stanozolol (STZ), as affected by co-treatment with probenecid, were studied in male Sprague-Dawley rats. Pharmacokinetic parameters following intravenous (i.v.) administration of STZ (20 mg kg-1 body wt.) were measured in both STZ-treated (control) and STZ plus probenecid-treated (treatment) groups. In order to assess the renal clearance of STZ, bolus doses of STZ and inulin (40 mg kg-1 body wt.) were injected i.v. either in the presence or absence of probenecid (40 mg kg-1 body wt.). The blood and urine concentrations of STZ were determined by capillary gas chromatography-mass spectrometry (GC-MS). In the probenecid treatment group, the area under the plasma disappearance and urinary excretion curves (AUC) of STZ were significantly decreased (P < 0.01) and the volume of distribution (Vd) and total clearance (CLt) were significantly increased statistically (P < 0.05 and P < 0.01, respectively). No remarkable differences in the urine flow rate, urine pH values, glomerular filtration rate (GFR) or renal clearance were observed in the treatment group. However, the clearance ratio in the treatment group was significantly increased from 11.72 to 17.27. From these results, it is suggested that the significant decrease of AUC, i.e. increase of disappearance of STZ in plasma by co-administration with probenecid, is due to the increase of the clearance ratio.

Animals↗
PubMed1985

Mineral analyses of vegetarian, health, and conventional foods: magnesium, zinc, copper, and manganese content.

The amounts of magnesium, zinc, copper, and manganese in 22 health and vegetarian foods and their conventional counterparts were measured. Increased levels of magnesium were associated with the presence of soy in vegetarian and health products. Zinc was low in the vegetarian meat and egg substitutes and in soy milk. Copper tended to be decreased in the vegetarian foods but increased in the health foods relative to levels in the conventional counterparts. Manganese levels were increased in most of the health and vegetarian food items relative to levels in the conventional foods.

Copper↗
PubMedDate not supplied

A comparison of the therapeutic efficacies of large loop excision of the transformation zone and hysterectomy for the treatment of cervical intraepithelial neoplasia III.

The technique of large loop excision of the transformation zone (LLETZ) came into vogue in the 1990s, and has been widely used in place of cold knife conization for diagnosis and treatment. Although its therapeutic efficacy for cervical intraepithelial neoplasia (CIN) has been confirmed and accepted in many countries, no direct comparison is available of the efficacies of LLETZ and hysterectomy for the treatment of CIN III, and unfortunately, hysterectomy is still widely used in many other countries. The aim of this analysis was to confirm the efficacy of LLETZ for the treatment of CIN III and to compare its results with those of hysterectomy. Between Jan. 1993 and Dec. 1997, 380 patients with CIN III were treated in the Seoul National University Hospital. We defined group I (n = 101) as those patients who underwent therapeutic LLETZ and follow-up only and group II (n = 279) as those patients who underwent hysterectomy following LLETZ. Three patients in groups I (3.0%) and II (1.1%) developed persistent/recurrent CIN or vaginal intraepithelial neoplasia (VAIN). This result was not statistically significant. Group II contained more patients with positive resection margins and glandular extensions than group I (P < 0.05), and these factors might have been confounding variables. However, when parameters influencing the rate of treatment failure were compared, no significant differences were found by logistic regression analysis (P > 0.05). The results obtained show that the LLETZ is almost identical in terms of its therapeutic efficacy to hysterectomy and that it should be accepted as a standard treatment for CIN III.

Adult↗
PubMedDate not supplied

Detection of deep myometrial invasion in endometrial carcinoma: comparison of transvaginal ultrasound, CT, and MRI.

OBJECTIVE: The aim of this study was to compare the accuracy of transvaginal US (TVUS), CT, and MRI in detecting deep myometrial invasion in endometrial carcinoma. MATERIALS AND METHODS: Twenty-six patients with endometrial carcinoma were evaluated with TVUS, CT, and MRI. The depth of myometrial invasion was estimated in each examination. The invasion depth was categorized into no/superficial and deep and was compared to surgical and pathologic findings. RESULTS: At pathologic examination, the depth of myometrial invasion was no/superficial in 16 patients and deep in 10. The accuracy/sensitivity/specificity of TVUS, CT, and MRI in detecting deep myometrial invasion were 69/50/81, 61/40/75, and 89%/90%/88%, respectively. The sensitivity and accuracy of MRI in detecting deep myometrial invasion were significantly higher than those of TVUS and CT (p = 0.049 for both sensitivity and accuracy). CONCLUSION: We recommend MRI instead of CT or TVUS for the evaluation of the depth of myometrial invasion in endometrial carcinoma.

Adenocarcinoma↗
PubMedDate not supplied

Polymorphism in the E6 gene of human papillomavirus type 16 in the cervical tissues of Korean women.

The aim of this study was to identify sequence variants in the HPV 16 E6 gene in Korean women and to examine the possible association between these sequence variants and cervical cancer development. We examined the HPV 16 DNA of 215 patients with no cervical disease (NCD) (n = 105) or with cervical neoplasia (n = 110) [cervical intraepithelial neoplasia (CIN), n = 61; invasive cervical carcinoma (ICC), n = 49] using the nested polymerase chain reaction (PCR) and PCR-directed sequencing methods. Fifty-four (NCD, n = 10; CIN, n = 17; ICC, n = 27) of the 215 samples contained HPV 16 E6 DNA, but only two (7.4%) of 27 ICC samples had prototype sequences. The most frequently found variation was D25E (in NCD, n = 8, 80%; in CIN, n = 9, 52.9%; in ICC, n = 23, 85.2%). This is a rare variation in western countries. No significance difference was found between the frequencies of D25E variation in cancerous and non-cancerous lesions. Among the 11 kinds of variants identified, four variants were novel and have been registered with GenBank. This study demonstrates that the D25 variant is the most prevalent E6 genomic variant type in Korean population. However, it was not found to be associated with an increased risk of ICC.

Cervix Uteri↗
PubMedDate not supplied

Epstein-Barr virus plays little role in cervical carcinogenesis in Korean women.

We examined whether Epstein-Barr virus (EBV) infection plays a role in cervical carcinogenesis in Korean women. EBV infection was examined using polymerase chain reaction (PCR) with two different primer pairs flanking the BamHI "W" fragment of EBV and by EBV-encoded small RNAs (EBER) in situ hybridization in various histologic types of cervical cancer, including 17 cases of squamous cell carcinoma, 36 cases of adenocarcinoma, and 3 cases of small-cell carcinoma. We also evaluated 20 cases of cervical intraepithelial neoplasia and 20 cases of normal uterine cervix. One case of squamous cell carcinoma and three cases of cervical intraepithelial neoplasia were positive for EBV DNA using PCR, but EBER in situ hybridization analysis showed that none of the PCR-positive cases expressed EBER. EBV DNA was not found using PCR in any of the 20 normal uterine cervices. From our results, EBV infection does not seem to play a role in cervical carcinogenesis in Korean women.

Adenocarcinoma↗