Biomedical subjects

S K Han

Publications and source records attributed to S K Han.

114 records · Page 7Linked to original sources

PubMed1976

Studies on red cell carbonic anhydrase types in Korean cattle.

Red cell carbonic anhydrase types in Korean cattle were investigated by means of starch gel electrophoresis. A carbonic anhydrase zone (X) located ahead zone F was found in 12 out of 502 Korean cattle. The distribution of CA phenotypes in 490 Korean cattle was CA FS type 92 and CA SS type 398. The CA FF type has not yet been recognized in Korean cattle. The gene frequencies were CAF = 0.094 and CAS = 0.906. No statistically significant differences were observed between gene frequencies in cattle from six different Korea provinces.

Animals↗

PubMed1975

Effect of inorganic additives on solutions of nonionic surfactants II.

The effect of electrolytes and urea on the cloud points of the following three nonionic polyoxyethylated surfactants was studied: cetyl, stearyl, and oleyl alcohol adducts containing 10 ethylene oxide units. The results were similar to those obtained previously with polyethylene oxide and with a polyoxyethylated alkylphenol. Nitrates of cations capable of forming stable solid complexes with model ethers like dioxane raised the cloud points in proportion to their concentrations by up to 35 degrees. They salted the surfactants in through complexation with the ether oxygens. The order of effectiveness in raising the cloud points was lead nitrate greater than hydrochloric acid greater than cadmium nitrate greater than sulfuric acid approximately equal to to magnesium nitrate greater than aluminum nitrate greater than nickel nitrate greater than lithium nitrate greater than calcium nitrate. Only the nitrates of sodium, potassium, ammonium, and cesium lowered the cloud points, salting the surfactants out. These cations do not form complexes with ether oxygens. Urea, sodium perchlorate, and sodium iodide, which break the structure of water, raised the cloud points. This salting-in process is ascribed to increased hydration of the ether groups of the polyoxyethylated surfactants due to depolymerization of water by urea and the perchlorate and iodide anions. The bromide, chloride, and sulfate of sodium lowered the cloud points. The surfactant with the alkylaryl moiety was salted in more extensively but salted out only slightly more than the three surfactants with the linear hydrocarbon chain. The data indicate the need for revising the theories of the effects of salts on the solubility of nonelectrolytes in water. None of the theories takes into account the interaction between electrolytes and nonelectrolytes, even though many nonelectrolytes compete with water as ligands for the cations.

Chemical Phenomena↗

PubMedDate not supplied

Alteration of cell growth and morphology by overexpression of transforming growth factor beta type II receptor in human lung adenocarcinoma cells.

TGF-beta is a potent inhibitory regulator of cell growth, which is transduced through interaction between type I (RI) and type II (RII) receptors that form heteromeric kinase complexes. Abnormal expression of these receptors has been identified in several human epithelial cancers and has been shown to be highly associated with resistance to TGF-beta. In this study, we investigated the expression of RI and RII in 13 human non-small cell lung cancer cell lines (NSCLCs) and demonstrated decreased or loss of RII expression in five lung cancer cell lines, but not of RI. Of these cell lines, the role of RII in NCI-H358 adenocarcinoma, which lacks RII and is insensitive to TGF-beta, was investigated by transducing this cell line with a recombinant retrovirus expressing full-length TGF-beta RII. Stably transfected cells showed significant increase in RII mRNA and protein expression. These cells responded to exogenous TGF-beta1 with suppressed proliferation in a dose-dependent manner and G1 arrest accompanied by morphological change distinct from control cells. We also investigated whether overexpression of dominant-negative RII (dnRII) in NCI-H441 adenocarcinoma, which is sensitive but expresses low levels of RII, could block signaling through the receptor complex. The overexpression of this kinase-domain-truncated RII by expressing the retroviral dnRII construct led to loss of the ability to respond to TGF-beta1 and an exhibition of uncontrolled growth. These results suggest a close association between the loss of the expression of wild-type TGF-beta RII and carcinogenesis in human lung cancer cells.

Adenocarcinoma↗

PubMedDate not supplied

Adenovirus expressing p27(Kip1) induces growth arrest of lung cancer cell lines and suppresses the growth of established lung cancer xenografts.

p27(Kip1) (p27) is a member of the universal cyclin-dependent kinase inhibitor (CDKI) family and a putative tumor suppressor gene. In several tumors including lung cancer, decreased expression of p27 is associated with poor prognosis. These observations suggest a potential role for p27 as a new gene therapy target. In this study, we constructed adenovirus expressing human p27 (ad-p27) and investigated its antitumor effects on human lung cancer cell lines. Upon transduction of several human lung cancer cells with ad-p27, a high level of p27 expression, with a decrease in cdk2 and an increase in cyclin E were observed. These changes resulted in G1/S arrest. Transduction of human lung cancer cell lines with ad-p27 showed in vitro growth inhibition and a marked suppression of colony formation upon soft agar clonogenic assay. Direct intratumoral injection of ad-p27 induced the growth suppression of established lung tumors in nude mice. From these observations, gene therapy using ad-p27 seems to offer a potential basis for the development of new cancer gene therapy modality and a useful tool to investigate the mechanisms of cell cycle control.

Adenoviridae↗

PubMedDate not supplied

CT manifestations of tracheobronchial involvement in relapsing polychondritis.

Two patients with relapsing polychondritis presented with tracheobronchial stenosis without clinical manifestation of nasal septum or ear lobe cartilage involvement. The CT findings included diffuse, smooth tracheobronchial wall thickening with narrowing and deformity of the lumen. Areas of dense calcium deposition within the thickened tracheal cartilage were seen. On follow-up after steroid medication, tracheobronchial wall thickening was decreased and the configuration of the tracheal lumen returned to normal.

Bronchi↗

PubMedDate not supplied

The inhibitory effect of adenovirus-mediated p16INK4a gene transfer on the proliferation of lung cancer cell line.

Abnormalities in the p16INK4a tumor suppressor gene are found in many lung cancer cell lines and primary lung cancer tissue. To examine its tumor suppressor function and potential adequacy in cancer gene replacement therapy, wild-type p16INK4a gene was inserted in an adenovirus derived gene delivery system and introduced into lung cancer cell lines (NCI-H441 and NCI-H157) that did not express p16INK4a. Western blot assay and immunocytochemistry demonstrated production of wild-type p16 protein in these cell lines. The biological function of exogenous p16 protein was confirmed by the inhibition of pRB phosphorylation. The expression of exogenous p16 protein via recombinant adenovirus significantly inhibited cancer cell growth and colony formation in vitro of NSCLC that can not express endogenous p16. The flow cytometric analysis showed these results correlated with G1 cell cycle arrest. These observations suggest the value of adenovirally-mediated p16INK4a gene replacement therapy for lung cancer.

Adenoviridae↗