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Biomedical subjects

S I Hong

Publications and source records attributed to S I Hong.

47 records · Page 3Linked to original sources
PubMed1991

Differential depression of lymphocyte subsets according to stage in stomach cancer.

Lymphocyte surface markers were determined in the peripheral blood lymphocytes (PBL) in 31 stomach cancer patients (15 males and 16 females) and 47 controls (20 males and 27 females) using an indirect immunofluorescence technique. The monoclonal antibodies used were Leu 2a (CD8, suppressor/cytotoxic T cells), Leu 3a (CD4, inducer/helper T cells), Leu 4 (CD3, pan T reagent), Leu 11 (CD16, natural killer cells) and Leu 12 (CD19, B cells). The numbers of PBL, CD3+, CD4+, CD8+, CD16+ and CD19+ cells significantly decreased and the CD4:CD8 value increased in patients with stomach cancer compared to those in healthy volunteers. In stage I, PBL, none of the PBL subsets nor the CD4:CD8 value were significantly different from those of the controls. In stage II, the numbers of PBL, CD3+, CD4+ and CD8+ cells decreased. In stage III, the CD19+ cells decreased in addition to the decreased subsets in stage II. In stage IV, PBL and all subsets measured decreased. The CD4:CD8 value showed significant increases in stages II, III and IV, because the CD8+ cells decreased to a greater extent than did the CD4+ cells. Changes in the subsets were analyzed with regard to age, sex, performance status and smoking history, no significant relation being observed between these factors and lymphocyte subsets. From the present study, we have demonstrated that lymphocyte subsets were differentially depressed in the order of T cells, B cells and natural killer cells, with progression of the stage of disease.

Adult↗
PubMed1991

Clinical usefulness of alpha-1-antitrypsin in the diagnosis of hepatocellular carcinoma.

Serum levels of alpha-1-Antitrypsin(AAT) were determined in 42 patients with hepatocellular carcinoma(HCC), 5 patients with metastatic liver cancer from stomach adenocarcinoma, 10 patients with liver cirrhosis, 10 patients with chronic hepatitis, and 66 controls by rocket immunoelectrophoresis using rabbit antiserum. The mean level of serum AAT was 225.5 +/- 73.0 mg/dl in 66 controls. The serum AAT in patients with HCC was 428.7 +/- 123.3 mg/dl, which was significantly higher than those in the controls and in patients with liver cirrhosis or chronic hepatitis(p less than 0.02). The level of AAT in metastatic liver cancer was similar to that in HCC. The positive cut-off value for elevation of serum AAT in this study was determined as above 445 mg/dl, the mean plus 3 standard deviations in the controls. Elevations of serum AAT were observed in 54.8%, 60.0%, and 10.0% of patients with HCC, metastatic liver cancer, and liver cirrhosis, respectively, while none of the patients with chronic hepatitis or the controls was positive. The serum AAT levels in 42 patients with HCC were analyzed with regard to sex, age, serum albumin, HBsAg, alpha-fetoprotein(AFP), and diameter of HCC, with no significant differences being observed between these factors and the serum AAT levels except for the diameter of the HCC. The positive rate in the HCC with a diameter of 10 cm or more was 74.1%, which was a significantly higher rate compared with 20.0% in the HCC with diameters less than 10cm. The positive rate of AFP for HCC was 61.9%, when 500 ng/ml of AFP was used as the cut-off value.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1979

Thermogenic control during exercise in a cold environment.

To determine whether the voluntary contractions of exercise interfere with involuntary shivering contractions, four male subjects were each exposed to a 10 degrees C environment for 60 min of rest followed by either another rest period or 30 min of cycleergometer exercise. On different days exercise was performed at zero load, light load, and moderate load. Each experiment was performed twice, resulting in a minimum of eight experiments for each subject. Esophageal temperature (Tes), eight skin temperatures (Tsk), oxygen uptake (VO2), and the integrated electrical activity from a neck muscle (EMG) were continuously monitored. Pedaling flushed cold blood into the body core, causing Tes to fall. The rate and absolute magnitude of the decrease in Tes was proportional to the intensity of exercise. Thermoregulatory VO2 (attributable to shivering) and EMG were inversely related both to Tsk during rest, prior to any changes in Tes, and to Tes during exercise, when Tsk was constant, once shivering thresholds were surpassed. The slope of the thermoregulatory VO2-to-Tes relation was significantly suppressed by increasing exercise intensity. The slope of the EMG-to-Tes relation was similarly suppressed; since the neck muscles are not involved in the additional acitivity of exercise, we concluded that the graded inhibition of shivering during exercise was of central origin rather than from the rhythmic contractions required to sustain exercise.

Adult↗
PubMedDate not supplied

Changes in natural killer cell activity and prostaglandin E2 levels during the progression of diethylnitrosamine-induced hepatocarcinogenesis in Fischer 344 rats.

The sequential changes of natural killer cell (NK) activity and prostaglandin E2 (PGE2) during hepatocarcinogenesis induced by diethylnitrosamine (DEN) in male Fischer 344 rats were investigated. DEN at a concentration of 40 ppm was administered in drinking water for 10 weeks. At weeks 5, 10, 20 and 30, rats were autopsied and the development of glutathione S-transferase placental form positive foci (GST-P+ foci) at weeks 5 and 10 and hepatocellular tumors at weeks 20 and 30 were examined. The labeling index of bromodeoxyuridine (BrdU) an indicator of DNA synthesis, was also sequentially checked. GST-P+ foci were found to increase with age. Hepatocellular nodules increased until week 20, but by week 30 when the incidence of hepatocellular carcinoma was 100%, the incidence of nodules had decreased. BrdU positive cells also increased with age, and by week 30 when the incidence of hepatocellular carcinoma was 100%, the number of BrdU-positive cells had decreased. NK cell activity increased until week 10, but at week 20, was less than in the untreated control group. The level of PGE2 increased until week 5, but at week 10, levels were not significantly different from those seen in the untreated control group. On the basis of these results, we concluded that NK activity is closely related to the progression of hepatocarcinogenesis, but PGE2 levels show no significant change.

Animals↗
PubMedDate not supplied

Alterations of p53 gene in primary gastric cancer tissues.

This study was conducted to investigate the p53 gene alterations in 25 surgically-resected gastric adenocarcinomas in the Korea Cancer Center Hospital by polymerase chain reaction single-strand conformation polymorphism analysis (PCR-SSCP) for exons 4-8 and immunohistochemical staining (IHCS) with anti-p53 antibody, DO-7. p53 mutations were detected in nine (36%) out of 25 cancer tissues by PCR-SSCP in exon 4-8: 0,1,1,6 and 1 mutations in exons 4,5,6,7 and 8, respectively. All tissues were also tested by IHCS, and positive staining was observed in 11 cases (44%). A discrepancy of the results between the two methods was observed in four cases. In one which showed positivity by PCR-SSCP a negative reaction by IHCS, the two base deletion was observed in exon 7. On the other hand, in three cases the mutation was detected only in IHCS but not in PCR-SSCP. The exact mechanism by which this discrepancy develops is not clear at present, although it may be due to the mutation of other exons not tested in this study or the relatively low sensitivity of the PCR-SSCP method. The incidence of p53 gene mutations was analysed according to pathologic stage and histological differentiation, but no significant difference was observed between the p53 alterations and these factors. By combined use of PCR-SSCP and IHCS, 48% of the 25 primary gastric cancer were considered to have mutations of the p53 gene. These results suggest that p53 mutation is not an infrequent event in primary gastric cancer and the p53 gene plays an important role in the carcinogenesis process of gastric cancer.

Adult↗
PubMedDate not supplied

Calcipotriol (MC 903), a synthetic derivative of vitamin D3 stimulates differentiation of squamous carcinoma cell line in the raft culture.

We investigated whether calcipotriol, a synthetic derivative of vitamin D3 has the ability to correct defects in the control of proliferation and differentiation of human squamous carcinoma cells using the raft culture of SCC 13 cell line. Calcipotriol treatment at concentrations of 10(-8)-10(-6) M considerably enhanced terminal differentiation of SCC 13 cells, as shown by the appearance of enucleated-eosinophilic cells as well as granular cells in their upper cell layers. Immunohistochemical staining showed marked increases in the differentiation of marker proteins such as keratin 1, involucrin, or filaggrin expressing cells in their upper layers. The elevated expression at protein level was confirmed by immunoblotting analysis. Furthermore, calcipotriol also stimulated basal cell marker proteins such as keratin 14 and EGF receptor. However, the numbers of basal marker expressing cells within the architecture of SCC 13 raft culture were markedly reduced upon calcipotriol treatment, and their localization was mainly restricted in the innermost cell layer. In addition, calcipotriol stimulated EGF receptor biosynthesis for the first 16 hours post treatment and subsequently inhibited [3H]-thymidine incorporation of SCC 13 cells at 24 hours. In this study, we have clearly demonstrated that the long term application of calcipotriol considerably improves the complex defects in the regulation of proliferation and differentiation of SCC 13 cells, as supported by morphological and biochemical observations. This provides an evidence that calcipotriol can be applied clinically as a potent differentiation inducer in the treatment of human squamous cell carcinoma.

Antineoplastic Agents↗
PubMedDate not supplied

Elevation of serum type IV collagen in liver cancer as well as liver cirrhosis.

Studies on the level of serum type IV collagen (IV C) have usually been focused on the disease with diffuse hepatic fibrosis. To investigate whether serum level of IV C was predictive for the development of liver cancer as well as liver cirrhosis, serum IV C level was measured by a one-step sandwich enzyme immunoassay. The mean level of serum IV C was 73.3 +/- 31.3 ng/ml in 48 controls. The levels (ng/ml) of IV C were 396.4 +/- 254.9, 429.6 +/- 320.7, 420.6 +/- 322.8, and 362.9 +/- 247.4 respectively in 11 patients with chronic hepatitis, 11 with liver cirrhosis, 16 with hepatocellular carcinoma (HCC) with cirrhosis, 10 with HCC without cirrhosis, and 10 with metasatic liver cancer, which were significantly higher than that in controls (p < 0.05). Serum IV C levels were also evaluated using a cut-off value which was determined as the mean plus two standard deviations in the controls, 136 ng/ml. The elevations above the cut-off value were observed in 91, 100, 80, and 90% respectively of 11 patients with cirrhosis, 16 with HCC with cirrhosis, 10 with HCC without cirrhosis, and 10 with metastatic liver cancer, while only one (9%) of 11 chronic hepatitis patients and none (0%) of 48 controls had elevated levels. The levels of serum IV C were analysed with regard to age, sex, serum levels of albumin, globulin, transaminases, alpha-fetoprotein, and diameter of liver mass, a significant difference being observed only between the diameter of HCC and serum level of IV C (p < 0.01). These results indicate that the measurement of serum IV C is a useful for the determination of primary and metastatic liver cancer as well as liver cirrhosis.

Adult↗
PubMedDate not supplied

Expression of a novel Bcl-2 related gene, Bfl-1, in various human cancers and cancer cell lines.

The expression of Bfl-1 gene, a novel Bcl-2 related gene, was determined by Northern blot analysis using a radiolabeled cDNA specific for Bfl-1 gene in 82 surgically resected tissue specimens of 28 gastric cancers, 15 colon cancers, nine breast cancers, eight bone and soft tissue sarcomas, five ovarian cancers, nine colon adenomas and eight gastric adenomas. A high rate of expression was observed in gastric and colon cancer, at 86 and 93%, respectively. In breast cancer, bone and soft tissue sarcoma and ovarian cancer, the expression rate was 33, 25 and 40%, respectively. In stomach cancer, the expression rate of Bfl-1 gene in metastatic lymph nodes was 82%, which was higher than 50% of the primary sites (p < 0.02). The intensity of RNA bands of the gastric cancer specimens was compared according to the stage, demonstrating that there was no difference in the expression levels of Bfl-1 gene between the stages in both primary sites and metastatic lymph nodes. Bfl-1 gene was expressed in three (33%) out of nine adenomas of the colon, while it was not detected in all eight gastric adenomas, We also examined the RNA expression of Bfl-1 gene in 22 human cancer cell lines consisting of five stomach cancer, four squamous cell carcinoma, three lung cancer, three cervical cancer, two colon cancer, two brain cancer, two leukemia and one osteosarcoma cell lines. Bfl-1 gene band was detected in one (5%) cervical cancer cell line, SiHa. The results of cancer tissue specimens indicate that Bfl-1 gene may play an important role in carcinogenesis of human cancers and may be involved in a relatively early phase of the adenoma-carcinoma sequence in colon cancer development. However, the mechanism responsible for the very low rate of expression in established cell lines is not clearly understood and further investigation is necessary to clarify the mechanism involved.

Adenoma↗
PubMedDate not supplied

Differential effects and transport kinetics of ascorbate derivatives in leukemic cell lines.

In order to investigate the differential effects of ascorbate derivatives on leukemic cell growth, we examined their stabilities and transmembrane transport efficiencies. The growth of HL-60 and U937 cells was dose-dependently inhibited by ascorbic acid and sodium ascorbate, but not by dehydroascorbic acid and magnesium ascorbyl 2-phosphate up to 200 microM. The growth-suppression by ascorbic acid was dependent on its redox state, showing a complete or partial reversion by ascorbate oxidase or FeCl3 addition, respectively. Three different patterns of intracellular ascorbic acid accumulation were observed by HPLC according to the species of ascorbate derivative applied for the incubation. Compared with the reduced form of ascorbic acid, the oxidized forms (dehydroascorbic acid, ascorbic acid plus ascorbate oxidase or FeCl3) were rapidly transported into cells and readily degraded, while magnesium ascorbyl 2-phosphate, a stable derivative of ascorbic acid, slowly elevated the intracellular level of ascorbic acid, reaching a plateau at 24 hours. We also measured the differential kinetics of ascorbic acid levels In culture supernatants following the addition of ascorbate derivatives. Ascorbic acid at 40, 10, or 1 microM was observed 3 hours following treatment with 100 microM of ascorbic acid, ascorbic acid plus FeCl3, or magnesium ascorbyl 2-phosphate, respectively. No ascorbic acid was found in the culture supernatant treated with dehydroascorbic acid. This order of ascorbic acid concentrations in culture supernatant reflects their growth-inhibitory effects. Thus the growth inhibitory effect of ascorbic acid appears to be dependent on its concentration in culture medium rather than its intracellular concentration. In conclusion, the results in this study indicate that the differential effects of ascorbate derivatives appear to be due to the actual concentration differences of the reduced form of ascorbic acid in culture medium following their addition, which is determined by their stability and efficiency of cellular uptake.

Ascorbate Oxidase↗