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Biomedical subjects

S H Cho

Publications and source records attributed to S H Cho.

At least 181 records · Page 10Linked to original sources
PubMed1995

Association of exposure to polycyclic aromatic hydrocarbons (estimated from job category) with concentration of 1-hydroxypyrene glucuronide in urine from workers at a steel plant.

OBJECTIVES: Increased risk of lung cancer has been associated with employment in the steel industry. This association is thought to be due in part to increased concentrations of polycyclic aromatic hydrocarbons (PAHs) in air found in this work environment. Measurement of PAH metabolites in human urine provides a means of assessing individual internal dose of PAHs. This study examined the relative contribution of occupation and smoking to urinary concentration of 1-hydroxypyrene glucuronide (1-OHPG) among a group of workers at a steel plant. METHODS: Concentrations of 1-OHPG in urine from 44 workers with jobs associated with increased air concentrations of PAHs and 40 workers with jobs with low or no exposure to PAHs were measured. 20 workers in each group were not current smokers. Urinary 1-OHPG was measured by synchronous fluorescence spectroscopy after immunoaffinity chromatography specific for PAH metabolites. RESULTS: Mean (SEM) urinary 1-OHPG concentration was 2.16 (0.42) pmol/ml urine among the 44 occupationally exposed workers compared with 0.38 (0.05) among the 40 workers with no or low exposure (P < 0.0001). Mean urinary 1-OHPG concentration was 1.82 (0.41) pmol/ml urine among the 44 current smokers compared with 0.75 (0.20) among the 40 non-smokers (P < 0.005). Mean 1-OHPG concentrations in non-smokers were 0.26 (n = 20), 0.70 (n = 15), and 2.84 pmol/ml urine (n = 5) for strata of exposure to PAHs (no or low, mid, and high) based on job category; the corresponding values in smokers were 0.55 (n = 20), 0.94 (n = 12), and 4.91 pmol/ml (n = 12), respectively. Multiple linear regression showed significant differences between subjects in different PAH exposure with increased concentrations of 1-OHPG in urine. Amounts of foods containing PAHs ingested by this group of workers were relatively low and did not contribute significantly to urinary 1-OHPG concentrations. CONCLUSIONS: These results indicate that 1-OHPG is a common urinary metabolite in people with recent occupational exposure to PAHs and is associated with both job category and estimated stratum of PAH exposure.

Adult↗
PubMed1995

Lipid peroxidation and 8-hydroxydeoxyguanosine formation in rats fed fish oil with different levels of vitamin E.

This study was conducted to investigate the protective role of vitamin E against the formations of lipid peroxides in plasma and tissues and of 8-hydroxydeoxyguanosine (8-OHdG) in livers of rats fed fish oil. Six-week-old male Sprague-Dawley rats were divided into four groups and fed experimental diets for 8 weeks. Three fish oil (F) groups were fed a menhaden fish oil and soybean oil (9:1) mixture as 10% (wt/wt) of their diet. These three groups (F0, FI, and FII) were provided with < or = 3, 45, and 209 IU of vitamin E/kg diet, respectively. The SI group was fed soybean oil with < or = 45 IU of vitamin E/kg diet. The F0 group had the highest levels of thiobarbituric acid-reactive substances (TBARS) in plasma (per milligram lipid), and liver, lung, heart, and kidney. The FI group had higher levels of TBARS than the SI group in plasma and tissues except the lung. In liver, the TBARS levels of the FII group were also higher than those of SI group, but in other tissues, similar levels were observed in the FII and SI groups. Plasma level of vitamin E was lowest in F0 group and vitamin E levels were generally lower in F groups than in SI group. These levels were expressed as vitamin E per milliliter of plasma. However, plasma E levels were similar when expressed per milligram plasma lipid. The liver 8-OHdG concentration tended to decrease as dietary vitamin E increased in the F groups, but there was no difference in the level of 8-OHdG between the FI and SI groups. These results suggest that vitamin E should be supplemented in fish oil feeding to prevent the enhanced lipid peroxidation and the formation of 8-OHdG in the body.

Administration, Oral↗
PubMed1995

Massive congenital intracranial teratoma--an autopsy case.

Massive congenital intracranial teratoma (MCIT) is a very rare tumor and only one case has been reported in Korea. We report a case of MCIT discovered in a male infant of 25 weeks of gestational age. Prenatal ultrasound revealed a large heterogenous echoic mass which almost replaced the intracranial content. The infant was severely macrocephalic with a small but normal appearing body. The cranial vault was almost entirely occupied by an 18cm sized, multilobulated, partially cystic mass that displaced the severely distorted and attenuated cerebral cortex. Microscopically, the bulk of the tumor was composed of embryonal neuroepithelium with mature glial tissue and choroid plexus. Cartilage, liver, mature squamous epithelium and differentiated mesenchymal elements such as muscle and adipose tissue were found within the tumor.

Adult↗
PubMed1995

Preventing collapse in early osteonecrosis of the femoral head. A randomised clinical trial of core decompression.

We performed a randomised trial on 37 hips (33 patients) with early-stage osteonecrosis (ON). After the initial clinical evaluation, including plain radiography and MRI, 18 hips were randomly assigned to a core-decompression group and 19 to a conservatively-treated group. All the patients were regularly followed up by clinical evaluation, plain radiography and MRI at intervals of three months. Hip pain was relieved in nine out of ten initially symptomatic hips in the core-decompression group but persisted in three out of four initially painful hips in the conservatively-treated group at the second assessment (p < 0.05). At a minimum follow-up of 24 months, 14 of the 18 core-decompressed hips (78%) and 15 of the 19 non-operated hips (79%) developed collapse of the femoral head. By survival analysis, there was no significant difference in the time to collapse between the two groups (log-rank test p = 0.79). Core decompression may be effective tin symptomatic relief, but is of no greater value than conservative management in preventing collapse in early osteonecrosis of the femoral head.

Adolescent↗
PubMed1994

Sialyl-Tn antigen expression occurs early during human mammary carcinogenesis and is associated with high nuclear grade and aneuploidy.

Sialyl-Tn (STn) antigen represents an aberrant glycosylation product of cell surface mucin in adenocarcinomas. We studied its expression in 40 breast carcinomas (35 of which included in situ carcinomas) by performing immunostaining with B72.3 monoclonal antibody. STn expression was observed in 50% of cases and was equally frequent in in situ and in invasive carcinomas. Positive STn staining significantly correlated with high nuclear grade (P = 0.001), aneuploidy (P < 0.001) and high S-phase fraction (P = 0.02). No correlation was observed between STn staining and age, menopausal status, presence of invasive component, or hormone receptor positivity. STn staining may provide an objective marker of dedifferentiation of breast tumors and should be investigated further for its prognostic value in breast cancers and as a biomarker of malignant transformation of breast epithelium.

Adult↗
PubMed1994

Lipid peroxidation and antioxidant status is affected by different vitamin E levels when feeding fish oil.

The protective role of vitamin E and changes in the status of several physiological antioxidants after feeding rats a fish oil diet were investigated. Six-week-old male Sprague-Dawley rats were divided into four groups and fed experimental diets for 8 wk. Three fish oil (FO) groups were fed a menhaden fish oil and soybean oil (SO) (9:1) mixture as 10% (w/w) of the diet. These groups were provided with < or = 3, 45 or 209 IU of vitamin E/kg diet. One SO group was used as control and was fed < or = 45 IU of vitamin E/kg diet. Plasma vitamin E levels, when expressed as vitamin E per mL plasma, were extremely low in the group fed FO and < or = 3 IU of vitamin E, and were lower in the groups fed FO than in the group fed SO. However, plasma vitamin E levels when expressed per mg plasma lipid were higher in the FO groups provided with < or = 45 and 209 IU of vitamin E than in the SO group. Compared with the SO group, plasma levels of thiobarbituric acid reactive substances (TBARS), when expressed per mg lipid, were higher in the three FO groups, plasma retinol levels were lower in the FO groups provided with < or = 3 and 45 IU of vitamin E, and ascorbic acid levels were lower only in the FO group provided with < or = 3 IU of vitamin E. Blood glutathione (GSH) levels were lower in all three FO groups than in the SO group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Effect of anisotropy corrections on the dynamic dose calculations in high dose rate (HDR) brachytherapy.

An analytic formalism utilizing a convolution technique is presented for the incorporation of anisotropy corrections into the dynamic (or transit) dose calculations in high dose rate (HDR) brachytherapy. A simple numerical implementation of the suggested formalism is also presented. Two calculational examples are provided in order to show some effects of anisotropy corrections on the dynamic dose calculations. Based on the results from these examples and published literature, the absence of anisotropy corrections in the dynamic dose calculations could result in a dosimetric error up to the order of 0.1 Gy during the full course of HDR brachytherapy treatments depending on fractionation and geometrical arrangement. Therefore, the incorporation of anisotropy corrections into dynamic dose calculations could eliminate this kind of error in HDR brachytherapy.

Algorithms↗
PubMed1994

Anisotropy measurements of a high dose rate Ir-192 source in air and in polystyrene.

Anisotropy measurements in air and in polystyrene were performed for a Nucletron microSelectron 10 Ci Ir-192 source. TLD rods of similar sensitivity (+/- 3%) were placed on a semicircle around the source center which had been precisely localized by either radiographic means or direct measurement. The anisotropy, expressed as a ratio of TLD reading at a given angle relative to the longitudinal source axis, over the reading at 90 degrees, was measured for distances between 1 and 10 cm from the source center. For both media, a marked anisotropy of the high dose rate source was found. In air, there is no detectable variation in anisotropy with distance up to 10 cm from the source. In polystyrene, however, the anisotropy becomes less pronounced with increasing distance due to scatter. For both media, no difference, within the estimated experimental accuracy of +/- 5%, was found between three consecutive sources installed by the vendor.

Air↗
PubMed1994

Estimation of the geometric means and the reference values of blood lead levels among Koreans.

Blood lead concentrations of Koreans who have not been exposed to lead occupationally, show a wide range of variation. Despite the fact that blood lead concentration reveals a long-normal distribution, geometric means and standard deviations have not been presented in almost all studies on blood lead levels in Koreans. A new meta-analytical method was applied to estimate the theoretical geometric means, the standard deviations of the logarithm, and the reference values of blood lead concentrations among Koreans based on arithmetic means and standard deviations reported, and to compare them to those of other countries. Estimated geometric means of Korean men, women, and men and women, were 18.03, 13.13, and 15.80 micrograms/dl, respectively. Values of 90, 95, and 99 percentile for Korean men were 31.81, 37.36, and 50.52 micrograms/dl, for women, 28.41, 35.34, and 53.24 micrograms/dl, and for men and women, 31.42 micrograms/dl, 38.17 micrograms/dl, and 54.95 micrograms/dl, respectively. These values are higher than those of neighboring countries, such as China and Japan.

Environmental Exposure↗
PubMed1994

Two cases of intestinal capillariasis in Korea.

The distribution of intestinal capillariasis has been extended continuously through Asian countries. The first case in Korea was reported in 1993, and here we add 2 more cases. One case is a 41-year old man who was diagnosed by both eggs in the feces and worms in the biopsy specimen of the ileum. This case was supposedly infected in Indonesia. The other is a 78-year old man, who has not been abroad, and suffered from intractable diarrhea. He was diagnosed by eggs in the feces, and several juvenile worms were collected after anthelmintic treatment. In both cases the treatment was successful by albendazole.

Adult↗
PubMed1994

The basal electrical skin resistance of acupuncture points in normal subjects.

The inhibitory component of the skin against given electrical current, also called as the electrical skin resistance, is subject to change in response to many factors, especially pain. In order to find out more definite relationship between pain and skin resistance, one should make measurement in the state devoid of any external disturbing stimuli to get the "basal skin resistance (BSR)", which is known to be different from point to point on body surface. Also, the "active points" have more consistent BSR characters than other points and most of them share same locations with "acupuncture points" which is easy to localize accurately and repeatedly in normal subject. Therefore, the comparison of BSR of certain acupuncture points of normal subject and pain-suffering subjects is expected to be able to figure out any pain-induced BSR changes. Our measurement at 16 acupuncture points (asymmetrical 8 pairs) of 10 normal subjects showed inconsistently asymmetrical distribution of the BSR values with significant order among themselves including left SP (spleen)-6 at their lowest position, but neither the measuring system itself nor any of the 16 points was statistically reliable enough for diagnostic purposes. So the measuring device needs to be improved with after evolution, and more acupuncture points need to be explored to complete our pain-related BSR map. In addition, the meaning of the above BSR distribution pattern is waiting to be explained through such efforts.

Acupuncture Points↗
PubMed1994

Angiography, scintigraphy, intraosseous pressure, and histologic findings in high-risk osteonecrotic femoral heads with negative magnetic resonance images.

One hundred twenty-six hips of 68 patients who were suspected of having osteonecrosis or being at risk for osteonecrosis were studied with magnetic resonance (MR) imaging. Abnormal patterns on MR imaging characteristic of osteonecrosis were observed in 98 hips. The remaining 28 hips (22 patients) with negative MR images underwent superselective angiography of the medial femoral circumflex artery. Angiography showed interruption of the superior retinacular arteries in 13 hips (12 patients), including 6 of 7 symptomatic hips. Bone scans were performed on 8 of 13 hips angiographically positive for osteonecrosis. Decrease of radionuclide uptake (cold lesions) was observed in all 8 of these femoral heads. Thirteen femoral heads with interruption of superior retinacular arteries underwent intraosseous pressure measurement and core biopsy. Intraosseous pressure was elevated in 11 hips. The results of histologic study showed evidence of early necrosis in 10 femoral heads. This study indicates that there are a considerable number of femoral heads at high risk, even when they have negative MR images. They do, however, show positive findings on angiography, scintigraphy (cold lesions), intraosseous pressure measurement, and histologic study.

Adolescent↗
PubMed1993

Genomic typing of hepatitis C viruses from Korean patients: implications of genome variation in the E2/NS1 region.

Comparative nucleotide sequence studies of a 2.4-kb cDNA fragment (nt -49 to 2361) of Korean-type hepatitis C virus (HCV) were carried out. The nt sequences of the Korean HCV isolates have stronger sequence homologies with type II HCV (Japanese HCV-BK) than with types I (HCV-1) or III (HCV-6). In addition, the net sequences of a part of the core region of ten different samples confirmed that prevalent HCV in Korea belongs to type II with the exception of one sample which belongs to type III. The nt sequence of a cDNA fragment of E2/NS1 region of HCV, from six different serum samples, which comprises the hypervariable regions-1 (HVR-1) and -2 (HVR-2), revealed sequence heterogeneity with type II HCV (75.4 to 80.7% nt homology and 75.5 to 79.7% amino acid homology). However, it was relatively well conserved among the Korean isolates, in fact, aa sequences of HVR-2 as well as HVR-1, converged into two groups. Also we found consensus sequences (T.V.G..AGRTT.G..SLE......K) in HVR-1. Thus, we propose that the conserved patterns in HVR-1 and -2 are characteristics of the six different Korean isolates.

Amino Acid Sequence↗
PubMed1993

Rapid and simple purification of human immunodeficiency virus 1 epitope gp41.

In order to develop a reliable and inexpensive serodiagnostic method, part of the transmembrane glycoprotein gene of HIV-1, gp41', (HIV-env 548-646) was cloned into an expression vector, pCT10 with a sequence encoding a hydroxylamine cleavage site and with a part of Lac Z gene (Lac 2": 834 base pairs) as a fusion partner. Overexpression of Lac Z"-gp41' was induced in E. coli and the gp41' fusion protein was purified to homogeneity by centrifugation, hydroxylamine cleavage and an ion-exchange chromatography. Western blot analysis and enzyme-linked immunosorbant assay (ELISA) using the purified gp41 fragment showed high sensitivity and specificity of gp41 as an antigen to detect anti HIV-1 antibodies in testing human sera. These results suggest that this simple and rapid purification method is reliable for obtaining a large quantity of purified gp41'.

Base Sequence↗
PubMed1993

An outbreak of Heinz body positive hemolytic anemia in chronic hemodialysis patients.

During the four month period, from December 1988 to March 1989, there was an outbreak of Heinz body positive hemolytic anemia in 34 patients undergoing hemodialysis in a 500-bed hospital, Seoul, Korea. The episodes of hemolysis were not reduced by changing the charcoal column and reverse osmosis system, or by adding ascorbic acid to the dialysate. The concentrations of nitrate, copper, aluminum and zinc in the treated water were all within the standards for hemodialysis. The chloramine concentration of the treated water was over 0.6 mg/L, markedly exceeding the allowable level of 0.1 mg/L. This high level of chloramine was proved to be due to the contamination of the water source by raw sewage. After we changed the source of water supply to another, no more episodes of hemolytic anemia occurred. It is concluded that chloramine is one of the major contaminants causing dialysis-induced hemolytic anemia and regular determinations are necessary, especially during winter and dry seasons.

Anemia, Hemolytic↗