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Biomedical subjects

Y S Kim

Publications and source records attributed to Y S Kim.

At least 19 recordsLinked to original sources

Tumor localization and biodistribution with radiolabeled monoclonal antibody against pancreatic cancer in tumor-bearing nude mice.

Nd2 is a murine monoclonal antibody produced against a mucin fraction purified from xenografts of a human pancreatic cancer cell line SW1990. Immunoperoxidase staining showed that the antigen recognized by Nd2 was present in 82.9% of pancreatic cancer tissues but not in tissues of normal pancreas and chronic pancreatitis. However Nd2 antigen was found not to be elevated in the sera of patients with pancreatic cancer. Four days after injection of 111In-Nd2 into athymic nude mice bearing SW1990 xenograft there was a higher accumulation in the tumor compared to 111In-normal mouse IgG1. When these mice were scanned with a gamma camera, labeled Nd2 was shown to accumulate in the tumor rapidly on the 1st day after injection and by the 4th day tumor accumulation was more distinctly visualized than non-specific accumulation in liver. These results indicate that Nd2 has high specificity and reactivity for pancreatic cancer and may have possible applicants in radioimmunodetection or targeting of therapeutic drugs in pancreatic cancer.

Animals

Prevalence of hepatitis C virus antibody among Korean adults.

To estimate the prevalence of hepatitis C virus (HCV) infection among Korean adults and to present the putative route of HCV transmission among them, serum samples from 4917 adults older than 20 years of age were tested for antibody to HCV (anti-HCV), and histories of blood transfusion and other pertinent information were obtained by self-administered questionnaires. The overall prevalence of anti-HCV was 1.7%; prevalence was 1.4% in subjects with normal levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), 3.3% in those with slightly elevated and 5.9% in those with markedly elevated levels of the enzymes. The prevalence of anti-HCV increased with increasing age (P < 0.01), but was not associated with blood transfusion. The present study suggests that the prevalence of HCV infection was 1.4% and that the major routes of HCV transmission may be other than blood transfusion in healthy Korean adults.

Adult

Regulation of fatty acid synthase at transcriptional and post-transcriptional levels in rat liver.

The regulation of fatty acid synthase in rat liver was investigated at transcriptional and post-transcriptional levels. When rats were fasted for 3 days and refed on a high-carbohydrate diet, the amounts of FAS in liver cytosol began to increase at 12 hours and further increased until 48 hours. The amount of mRNA for FAS began to increase at 6 hours and reached to a maximum level at 12 hours, indicating that the expression of mRNA for FAS precedes the increase of FAS protein pool. After 12 hours the amounts of mRNA gradually decreased and remained at a much lowered level between 24 and 48 hours. The elevated amount of FAS mRNA reflected on the amount of FAS protein in the first 24 hours, but these two parameters were not paralleled thereafter, probably due to the changes in the translational efficiencies. The run-on transcriptional activity of FAS gene began to increase at 4 hours after refeeding a high-carbohydrate diet and further increased to reach a maximum level 25 fold of the initial level at 12 hours, followed by a 16 fold level between 24 and 48 hours. The elevation of run-on transcriptional activity of FAS gene preceded the increase of FAS mRNA in the liver cytosol by 2 hours, and a similar increasing pattern was observed until 12 hours. However, FAS mRNA concentration decreased gradually after 12 hours, while the transcriptional activity remained at a high level until 48 hours. The changes in FAS mRNA content in the cytosol of rat liver were closely related to the transcriptional activity of FAS gene in the early phase of induction, but another regulatory mechanism seems to operate in the decrease of mRNA after 12 hours.

Animals

Thyrotropin-secreting pituitary microadenoma.

We present a 45-yr-old male with clinical signs and symptoms of mild hyperthyroidism, high serum levels of T3, T4, and FT4 as well as serum TSH concentration. The elevated alpha-subunit level and alpha-subunit/TSH molar ratio were also observed. These findings indicated the presence of hyperthyroidism due to inappropriate secretion of TSH, whose neoplastic origin was documented by nuclear magnetic resonance scan showing a 0. 6 cm pituitary adenoma. Selective pituitary adenomectomy was completely successful; alpha-subunit, TSH, T3, T 4, and FT4 normalized, and euthyroidism was restored. Light microscopic immunohistochemistry showed that the adenoma was composed of TSH-secreting cells.

Adenoma

Effect of benzyl-alpha-GalNAc, an inhibitor of mucin glycosylation, on cancer-associated antigens in human colon cancer cells.

Many cancer-associated antigens are present on mucin glycoproteins. These include peripheral antigens such as sialyl Lea and sialyl Lex and core region carbohydrate antigens such as T, Tn, and Sialyl Tn. We have recently described an inhibitor of mucin glycosylation, benzyl-alpha-GalNAc. The purpose of this study was to determine its effect on expression of mucin carbohydrate antigens. HM7 colon cancer cells were treated for 2 days in culture with 2 mM benzyl-alpha-GalNAc. This treatment did not affect viability or doubling time, but inhibited synthesis of [3H]glucosamine-labeled mucins. There was also secretion of benzyl-oligosaccharides and a decrease in the proportion of long oligosaccharides on 3H-labeled mucins. Mucins were purified from spent media by gel filtration and assayed for binding of monoclonal antibodies and lectins. Mucins from benzyl-alpha-GalNAc-treated cells had increased binding of peanut agglutinin (specific for T antigen, Gal beta 3GalNAc) and Vicia villosa agglutinin B4 (specific for Tn antigen, GalNAc alpha-Thr/Ser), but decreased binding of monoclonal antibodies 19-9, SNH3, and 91.9H (specific for sialyl Lea, sialyl Lex, and sulfomucin, respectively). Treatment of the cells with benzyl-alpha-GalNAc also decreased their binding to E-selectin (ELAM-1), which recognizes sialyl Lea and sialyl Lex. Thus, benzyl-alpha-GalNAc treatment, which decreases the level of peripheral carbohydrate carbohydrate antigens on mucins with accumulation of core region antigens, may be useful in modifying the immunological and biological properties of colon cancer cells.

Acetylgalactosamine

Single-center experience of unrelated living-donor renal transplantation in the cyclosporine era.

Renal transplantation from the unrelated living-donor might be an alternative when the cadaveric or related donor is not available, because graft and patient survival rates are superior to those of kidneys from cadaveric donors and even comparable to those from related donors. Among the many factors that might contribute to these excellent results, we believe that the good quality of kidneys (lacking preservation or ischemic injury) is the most important one. In addition, our criteria for patient selection requiring well-matched HLA typing might partially contribute to our success. For the successful renal transplantation program using unrelated-living donors, high ethical standards, accumulated experience from living-related donor transplantation, and dedicated professionalism are strongly recommended.

ABO Blood-Group System

Topographical distribution of estrogen target cells in the forebrain of platyfish, Xiphophorus maculatus, studied by autoradiography.

In the platyfish, Xiphophorus maculatus, after injection of [3H]estradiol-17 beta, nuclear concentration of radioactivity is observed in certain cells of the forebrain. These labeled cells are accumulated in periventricular midline regions that include in the telencephalon the ventral precommissural and dorsal supracommissural areas, and in the diencephalon the preoptic, central hypothalamic and thalamic areas. The specialized ependyma of the subcommissural organ also shows nuclear concentration of radioactivity, while other ependymal cells remain unlabeled. Similar to other vertebrate classes, the accumulations of estrogen target cells exist characteristically in the vicinity of the ventricular system, especially its recesses. This implies close topographical relationships between estrogen target cells and the ventricular recess organs, including the optic recess organ, the infundibular recess organ, the paraventricular organ and the subcommissural organ. Different from other vertebrate classes, no pallial accumulations of estrogen target cells are seen in the teleost.

Animals

Estrogen target cells in the pituitary of platyfish, Xiphophorus maculatus.

The distribution of estradiol-concentrating cells in the pituitary of the platyfish, Xiphophorus maculatus, is studied after the injection of 3H estradiol-17 beta by thaw-mount autoradiography. Autoradiograms prepared 2-8 h after the injection show nuclear concentration of radioactivity in certain cells of the rostral pars distalis, pars intermedia and pars nervosa. Radioactively labeled cells are identified as gonadotropes by a combined technique of thaw-mount autoradiography and immunoperoxidase staining with antiserum to ovine LH. Approximately 80% of the immunoreactive LH cells show a concentration of radioactivity in their nuclei. These observations indicate that in teleosts, as in mammals, estradiol has a direct effect on pituitary gonadotropes.

Animals

Protein digestion and absorption in the blind loop syndrome.

Protein digestion and absorption was studied in rats with 6-week-old surgically constructed self-filling intestinal blind loops and steatorrhea, ie, blind-loop animals and controls were fed a 14C-labeled protein meal containing a nonabsorbable marker, 51CrCl3, and sacrificed 1 or 2 hr later. Intestinal contents were analyzed for 14C, 51Cr, protein, trypsin, and the products of digestion. At 1 hr, 14C absorption was greater in controls, but at 2 hr there was no difference in absorption between the two groups. Marker studies showed that blind-loop filling resulted in a delay of the progression of intestinal contents distally. Intraluminal trypsin and porteolysis were similar in the two groups. Endogenous protein was greater in the blind-loop animals. The early stages of the blind-loop syndrome may be characterized by delayed protein absorption secondary to blind-loop filling, which is compensated for by the distal gut resulting in an absence of overall protein malabsorption.

Animals

Protein digestion and absorption in man. Normal mechanisms and protein-energy malnutrition.

Protein is an essential nutrient normally assimilated in an efficient manner following the action of gastric, pancreatic and small intestinal enzymes. After hydrolysis, protein digestion products in the form of amino acids and small peptides undergo mucosal uptake by distinct transport mechanisms. Although gastric and pancreatic enzymes are important, the small intestine appears to be the critical rate-limiting tissue in this process. Impaired intake, assimilation or excessive enteric protein loss may occur with several diseases leading to protein-energy malnutrition. Although the clinical and laboratory features of this condition are nonspecific and wide ranging in spectrum, their presence may provide a clue to underlying disease and serve as an index of patient nutritional status. Disease of the exocrine pancreas or small intestine may cause significant protein-energy malnutrition which, in turn, can cause major structural and functional abnormalities in these tissues.

Dietary Proteins

The contaminated small bowel syndrome.

Contamination of the small bowel with an abnormal microflora causes a variety of disturbances of intraluminal digestion and of mucosal function resulting in malabsorption of fat, protein, carbohydrate, electrolytes and vitamin B12. Indirect clinical tests for the presence of small bowel bacterial overgrowth must be supported by careful roentgenologic examination of the small intestine and intestinal aspiration studies to establish a firm pretreatment diagnosis. However, the reversal of absorptive defects by antibacterial therapy is valuable confirmatory evidence.

Anti-Bacterial Agents

Dual sites of occurrence of malonyl-CoA decarboxylase and their possible functional significance in avian tissues.

1. Uropygial glands of domestic goose and mallard which synthesize methyl-branched fatty acids, contain large quantities of cytosolic malonyl-CoA decarboxylase and a small quantity of mitochondrial enzyme. 2. Uropygial glands of chicken and the liver of geese which generate little methyl-branched acids, contain only small quantities of malonyl-CoA decarboxylase and in such cases the enzyme is in the mitochondria. 3. The mitochondrial decarboxylase from the uropygial gland and liver of goose is immunologically similar to the cytosolic decarboxylase of the uropygial gland. 4. The mitochondrial enzyme probably protects the mitochondrial enzymes which are susceptible to inhibition by malonyl-CoA, whereas the cytosolic enzyme promotes the synthesis of methyl-branched acids.

Animals