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Biomedical subjects

S I Choi

Publications and source records attributed to S I Choi.

34 records · Page 2Linked to original sources

Pleomorphic fibroma on the scalp.

We present the eleventh case of benign pleomorphic fibroma arising on the scalp in a young Korean woman. Histopathologically these lesions were characterized by a polypoid or dome-shaped cutaneous fibrous mass with sparse cellularity but striking nuclear atypia and rare mitotic figures. They all showed benign clinical behavior, despite these histopathological findings.

Actins↗

Congenital giant pigmented nevus associated with angiolipoma.

We report a 20-year-old-Korean woman with a congenital giant pigmented nevus and angiolipoma. She was admitted our department with a large, dark, pigmented lesion on the right flank and abdomen and a slowly growing mass on the right flank area since birth. On biopsy, the specimen taken from the giant pigmented patch showed typical findings of compound nevus. The right flank mass was surgically removed. The specimen was composed of mature fat cells with an increased vascular component. These findings are compatible with angiolipoma.

Adult↗

Distribution of Lipiodol in hepatocellular carcinoma.

Intrahepatic distribution of Lipiodol and I-131 Lipiodol infused via the hepatic arteries was evaluated in six patients with HCC who had undergone hepatic lobectomy or segmentectomy. CT scan and gamma camera radiograph confirmed that the oily contrast material or I-131 radioactivity accumulated selectively in the tumor over a long period. One to two thirds of the tumor mass appeared necrotic, although the extent tended to be larger in the case of radioactive Lipiodol infusion. The tumor cells contained numerous lipid globules within the cytoplasm. Also, oil red 0 stain demonstrated that the individual tumor cells had non-globular lipid on their surface. In conclusion, Lipiodol leaks out of the vascular spaces to attach to the cancer cell membrane as a non-globular lipid as well as to enter the cancer cells as a globular lipid. This phenomenon specific to cancer cells suggests a biochemical membrane change which may have occurred during carcinogenesis, causing alteration of membrane transport and cell death.

Adult↗

Acute nonlymphocytic leukemia in 171 children.

The initial features, response to therapy, complications, cause of death, and prognostic factors of 171 consecutive children with ANLL are described and compated to historical data for adults with ANLL and for children with ALL. Major differences between children and adults with ANLL include a higher frequency of CNS leukemia and a lower frequency of early deaths in the children. The most important differences between children with ANLL and ALL are the absence of a peak age of incidence in ANLL and the far better response to therapy in ALL. Among features present at 100,000/mm3 or above, and no palpable hepatomegaly had significantly longer survivals, while patients with platelet counts below 10,000/mm3 had significantly shorter survivals. The frequency and duration of remission were significantly better with three protocols used since 1968 than previously. However, even with these protocols, the results were far from satisfactory, with a complete remission frequency of 66%, a median duration of hematological remission of 6 months, and a median duration of survival of 10 months. The striking contrast of these results in childhood ANLL with current results in childhood ALL underscores the need for novel, imaginative therapeutic approaches for ANLL.

Acute Disease↗

Novel secretion system of recombinant Saccharomyces cerevisiae using an N-terminus residue of human IL-1 beta as secretion enhancer.

An N-terminus sequence of human interleukin 1beta (hIL-1beta) was used as a fusion expression partner for the production of two recombinant therapeutic proteins, human granulocyte-colony stimulating factor (hG-CSF) and human growth hormone (hGH), using Saccharomyces cerevisiae as a host. The expression cassette comprised the leader sequence of killer toxin of Kluyveromyces lactis, the N-terminus 24 amino acids (Ser5-Ala28) of mature hIL-1beta, the KEX2 dibasic endopeptidase cleavage site, and the target protein (hG-CSF or hGH). The gene expression was controlled by the inducible UAS(gal)/MF-alpha1 promoter. With the expression vector above, both recombinant proteins were well secreted into culture medium with high secretion efficiencies, and especially, the recombinant hGH was accumulated up to around 1.3 g/L in the culture broth. This is due presumably to the significant role of fused hIL-1beta as secretion enhancer in the yeast secretory pathway. In our recent report, various immunoblotting analyses have shown that the presence of a core N-glycosylation resident in the hIL-1beta fragment is likely to be of crucial importance in the high-level secretion of hG-CSF from the recombinant S. cerevisiae. When the N-glycosylation was completely blocked with the addition of tunicamycin to the culture, the secretion of hG-CSF and hGH was decreased to a negligible level although the other host-derived proteins were well secreted to the culture broth regardless of the presence of tunicamycin. The N-terminal sequencing of the purified hG-CSF verified that the hIL-1beta fusion peptide was correctly removed by in vivo KEX2 protease upon the exit of fusion protein from Golgi complex. From the results presented in this article, it is strongly suggested that the N-terminus fusion of the hIL-1beta peptide could be utilized as a potent secretion enhancer in the expression systems designed for the secretory production of other heterologous proteins from S. cerevisiae.

Enteropeptidase↗

Evaluation by contrast-enhanced MR imaging of the lateral border zone in reperfused myocardial infarction in a cat model.

OBJECTIVE: To identify and evaluate the lateral border zone by comparing the size and distribution of the abnormal signal area demonstrated by MR imaging with the infarct area revealed by pathological examination in a reperfused myocardial infarction cat model. MATERIALS AND METHODS: In eight cats, the left anterior descending coronary artery was occluded for 90 minutes, and this was followed by 90 minutes of reperfusion. ECG-triggered breath-hold turbo spin-echo T2-weighted MR images were initially obtained along the short axis of the heart before the administration of contrast media. After the injection of Gadomer-17 and Gadophrin-2, contrast-enhanced T1-weighted MR images were obtained for three hours. The size of the abnormal signal area seen on each image was compared with that of the infarct area after TTC staining. To assess ultrastructural changes in the myocardium at the infarct area, lateral border zone and normal myocardium, electron microscopic examination was performed. RESULTS: The high signal area seen on T2-weighted images and the enhanced area seen on Gadomer-17-enhanced T1WI were larger than the enhanced area on Gadophrin-2-enhanced T1WI and the infarct area revealed by TTC staining; the difference was expressed as a percentage of the size of the total left ventricle mass (T2= 39.2 %; Gadomer-17 =37.25 % vs Gadophrin-2 = 29.6 %; TTC staining = 28.2 %; p < 0.05). The ultrastructural changes seen at the lateral border zone were compatible with reversible myocardial damage. CONCLUSION: In a reperfused myocardial infarction cat model, the presence and size of the lateral border zone can be determined by means of Gadomer-17- and Gadophrin-2-enhanced MR imaging.

Animals↗