• 대한의생명과학회지
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• 제11권4호
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• pp.421-427
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• 2005

To evaluate the diagnostic significance of p16 overexpression in human hepatocellular carcinoma (HCC), we analyzed p16 status and growth inhibitory patterns by p16 overexpression in HCC cell lines having different pRE status. SKHep1 and SNU449 cells show homozygous deletion of p16. The p16 gene in SNU398 cell is inactivated at posttranscription level. Adenovira1-p16 (Ad-p16) infection inhibits the cell growth in Hep3B, SNU398, and SNU449. Failure of growth inhibition in SKHepl results from the low transduction efficiency of adenovirus. The p16-mediated growth inhibition shows G 1 phase arrest in pRE-positive SNU449 but not in pRE-negative Hep3B. These results suggest that therapeutic efficacy of p16 gene might be considered on the transduction efficiency and the toxicity of adenoviral vector. Beside, growth inhibitory effect of p16 could be exerted through either pRE-dependent or -independent pathway.

• 대한의생명과학회지
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• 제11권4호
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• pp.447-453
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• 2005

A total of 108 strains of MRSA (Methicillin-resistant Staphylococcus aureus) clinical isolates was collected from $121^{st}$ general hospital (U.S. military hospital), Korean healthcare facility from January to March in 2005 and Wonju Christian hospital in 1999. Antimicrobial susceptibility test by Vitek System and MIC test using oxacillin and cephalothin stripes by E-test were executed. PCR based detection of mecA gene was performed on the all of MRSA clinical isolates, too. MRSA clinical isolates were characterized with antimicrobial resistance patterns, PCR based detection of mecA gene and validation of the multiplex PCR strategy of SCCmec among clinical isolates.

• 대한의생명과학회지
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• 제11권4호
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• pp.473-479
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• 2005

Possible mechanism of decreased catechol-O-methyltransferase (COMT) activity in cholestatic rat liver was studied. Hepatic and serum COMT activities were determined from the experimental rats with common bile duct ligation (CBDL). The Michaelis-Menten constants in this hepatic enzyme were also measured. The activities of cytosolic, mitochondrial and mircosomal COMT as well as their Vmax values were found to be decreased significantly in CBDL plus taurocholic acid (TCA) injected group than in the control group, such as CBDL alone groups. However, their Km values in the experimental groups did not vary. Serum COMT activity increased slightly in the CBDL plus TCA injected group than in the control group. The above results suggest that TCA represses biosynthesis of the COMT in the liver. The elevated activity of the serum COMT is believed to be caused by the increment of membrane permeability of hepatocytes upon TCA mediated liver cell necrosis.

• 대한의생명과학회지
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• 제11권4호
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• pp.493-501
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• 2005

Circadian rhythms, time on a scale of about 24 hours, are present in a number of organisms including animals, plants, and bacteria. The control of the biochemical, physiological and behavioral processes is regulated by endogenous clocks in the suprachiasmatic nucleus (SCN). At the core of this timing mechanism is molecular machinery that are present both in the brain and in the peripheral tissues throughout the body, and even in a single cultured cell. In this study, we performed two-dimensional gel electrophoresis to figure out any correlation between protein expression patterns and the requirement of two canonical clock proteins, either mPER1 or mPER2, by comparing global protein expression profiles in livers from wildtype or mPer1/mPer2 double mutant mice. We could identify several differentially expressed protein candidates with respect to time and genotypes. Further analysis of these candidate proteins in detail in vivo will lead us to the better understanding of how circadian clock functions in mammals.

• 대한의생명과학회지
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• 제11권4호
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• pp.503-508
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• 2005

Possible mechanisms of increased serum aryl sulfotransferase (AST) isozyme activities in cholestatic rats were studied. Serum AST-I, II and -III, IV isozymes activities were determined from the experimental rats with common bile duct ligation (CBDL) or choledocho-caval shunt (CCS). The activities of serum AST-I, II and -III, IV isozymes were found to be increased significantly in both the CCS plus taurocholic acid (TCA) injected group, and the CBDL plus TCA group than those in each control group, such as CCS or CBDL alone groups. The above results suggest that the elevated serum AST most likely due to increased hepatocyte membrane permeability caused by TCA mediated liver cell necrosis.

• 대한의생명과학회지
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• 제10권2호
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• pp.75-84
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• 2004

Massive identification of differentially expressed patterns has been used as a tool to detect genes that are involved in disease related process. We employed circular single stranded sense molecules as probe DNA for a DNA chip. The circular single stranded DNAs derived from 1,152 unigene cDNA clones were purified in a high throughput mode from the culture supernatant of bacterial transformants containing recombinant phagemids and arrayed onto silanized slide glasses. The DNA chip was examined for its utility in detection of differential expression profile by using cDNA hybridization. Hybridization of the single stranded probe DNA were performed with Cy3- or Cy5-labeled target cDNA preparations at $60^\circ$C. Dot scanning performed with the hybridized slide showed 29 up-regulated and 6 down-regulated genes in a cancerous liver tissue when compared to those of adjacent noncancerous liver tissue. These results indicate that the circular single stranded sense molecules can be employed as probe DNA of arrays in order to obtain a precious panel of differentially expressed genes.

• 대한의생명과학회지
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• 제12권2호
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• pp.127-130
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• 2006

It is important to coordinated interaction among neurons, astrocytes and endothelial cells to maintain the function of brain. To study their regulatory mechanisms in vitro system, the co-culture system among the isolated cells from brain may be needed. However, the method for purifying brain microvascular endothelial cells (BMEC) far culture have not established yet. In this study, the proper culture methods of mice cells using two different strains, CD1 and C57BL6, to obtain the pure and plentiful endothelial cells were described. The flatted-round forms of CD1 endothelial cells grew on the collagen-IV coating plates, while the purified cells from C57 mice preferred type collagen-I dishes for their growth. Both cells displayed anti-PECAM-1 (CD31) and von Willebrand Factor immune-reactivity. These results indicated that different coating materials not only improve attachment of isolated cells but also promoting growth of cells, suggesting that this method of purifying murine Brain microvascular endothelial cells (BMEC) provides a suitable model to investigate blood-brain-barrier (BBB) properties within neurovascular unit in vitro.

• 대한의생명과학회지
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• 제13권2호
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• pp.157-160
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• 2007

Endoplasmic reticulum (ER) plays formation of disulfide bonds and proper folding of secretory proteins. Cellular responses to ER stress enhances the stress-activated kinase pathway and the induces a lot of immediate-early genes. Among of them, the early growth response-1 (Egr-1), a transcription factor, which plays an important role in cell growth, development, differentiation, apoptosis and various types of injury. For that reason, we have tested the expression of Egr-1 against ER stress inducible drugs (tunicamycin, DTT, A23187 and BFA) to understand what kind of aspect occurred by ER stresses.

• 대한의생명과학회지
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• 제14권1호
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• pp.59-62
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• 2008

This experiment was performed to study the effect of TSH (thyroid-stimulating hormone) on the expression of endoplasmic reticulum (ER) chaperones in the rat thyrocytes FRTL-5 cells. Although the expressions of ER membrane kinases (ATF6, IRE1 and PERK) were specially enhanced under absence of TSH, no remarkable up- or down regulations of ER chaperones (BiP, CHOP and Calnexin) were detected by TSH. We firstly report here that TSH by dose up-regulated expression of ER membrane kinases in FRTL-5 culture thyrocytes.

• 대한의생명과학회지
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• 제14권1호
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• pp.63-68
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• 2008

The aqueous extract from the fruit body of Lentinus edodes was evaluated for inhibitory activities against $\alpha$-glucosidase isolated from Spargue-Dawley male rats. A aqueous extract of Lentinus edodes exhibited 13.8% inhibitory activity on using 2 mM p-nitrophenyl $\alpha$-D-glucopyranoside as a substrate ($IC_{50}$ 75.3 mg/ml). The aqueous extract of Lentinus edodes inhibition type on $\alpha$-glucosidase was determined to be competitive inhibition. When it was oral administered to increase of blood glucose levels after STZ-induced in a dose dependent dietary. These results suggest that aqueous extract of Lentinus edodes effect a metabolism of intestine, and thereby reducing the increase of blood glucose after STZ-induced.