Chang-Ho Cho

The Significance of p53 and K-ras Immunocytochemical Staining in the Diagnosis of Malignant Biliary Obstruction by Brush Cytology during ERCP

BACKGROUND/AIMS Brush cytology during ERCP can provide a pathologic diagnosis in malignant biliary obstruction. K-ras and p53 mutations are commonly found in biliary and pancreatic cancers. We evaluated the diagnostic yield of brush cytology and the changes obtained by adding p53 and K-ras staining. METHODS One hundred and forty patients with biliary obstruction who underwent ERCP with brush cytology during a 7-year period were included. The sensitivity and specificity of brush cytology only and with the addition of p53 and K-ras staining were obtained. RESULTS Malignant biliary obstruction was confirmed in 119 patients. The sensitivity and specificity of brush cytology were 78.2% and 90.5%, respectively. The sensitivity of cytology was 77.3% at the ampulla-distal common bile duct (CBD), 92.6% at the mid common hepatic duct (CHD), and 94.7% at the proximal CBD-CHD (p<0.05); these values did not differ with the degree or the length of the obstruction. In the 97 patients who received additional p53 and K-ras staining, the sensitivity of cytology plus p53 was 88.2%, cytology plus K-ras was 84.0%, and cytology plus p53 and K-ras was 88.2%. The sensitivity of cytology plus p53 was higher than that of brush cytology only (95% confidence interval: 83.69-92.78 vs 72.65-83.65) but not that of cytology plus K-ras. CONCLUSIONS Brush cytology for malignant biliary obstruction has a high diagnostic accuracy. Adding p53 staining can further improve the diagnostic yield, whereas K-ras staining does not.

Neuroprotective Effect of Chuk-Me-Sun-Dan on NMDA- and AMPA-Evoked Nitric Oxide Synthase Activity in Mouse Brain

Chukmesundan (CMSD) is composed of 8 medicinal herbs including Panex ginseng C.A. MEYER, Atractylodes macrocephala KOID, Poria cocos WOLF, Pinellia ternata BREIT, Brassica alba BOISS, Aconitum carmichaeli DEBX, Cynanchum atratum BGE, and Cuscuta chinensis LAM and used for the treatment of various symptoms accompanying hypertension and cerebrovascular disorders. This study was carried out to examine the effects of CMSD on N-methyl-D-aspartate (NMDA)-evoked, and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-evoked nitric oxide synthase (NOS) activity in mouse brain. In adult forebrain, CMSD influences neuronal maintenance and is neuroprotective in several injury models through mechanisms that are incompletely understood. Interaction is observed between CMSD and nitric oxide (NO). Because NO affects both neural plasticity and degeneration, we hypothesized that CMSD might rapidly modulate NO production. Using in vivo microdialysis we measured conversion of L-[14C]arginine to L-[14C]citrulline as an accurate reflection of NOS activity in adult mouse hippocampus. CMSD significantly reduced NOS activities to 62% of basal levels within 2 days of onset of delivery and maintained NOS activity at less than 45% of baseline throughout 3 days of delivery. These effects did not occur with control (distilled water) and were not mediated by effect of CMSD on glutamate levels. In addition, simultaneous delivery of CMSD treatment prevented significant increases in NOS activity triggered by the glutamate receptor agonists NMDA and AMPA. Rapid suppression by CMSD of basal and glutamate-stimulated NOS activity may regulate neuromodulatory functions of NO or protect neurons from NO toxicity and suggests a novel mechanism for rapidly mediating functions of CMSD. It is shown that NMDA receptor stimulation leads to activation of p21ras (Ras) through generation of NO via neuronal NOS. The competitive NOS inhibitor, L-nitroarginine methyl ester, and CMSD prevents Ras activation elicited by NMDA, thus supporting the physiologic relevance of endogenous NO regulation of Ras. These results suggest that Ras is a physiologic target of endogenously produced NO and indicates a signaling pathway for NMDA receptor activation that may be important for long-lasting neuronal responses.

Inhibitory Effects of Type IV Collagenase by Disulfiram

기질의 침윤과 전이를 특징으로 하는 악성종양 세포는 세포외 기질이나 기저막에 의존적으로 작용한다. 세포외 기질을 분해하는 효소인 matrix metalloproteinase (MMP) 계들의 발현 및 활성증가는 대부분의 악성종양세포에서 전이와 침윤를 촉진시킨다. MMP family 가운데 특히 type Ⅳ collagenase 활성을 지닌 MMP-2와 MMP-9은 세포외기질의 중요한 구성분인 collagen, fibronectin을 분해하는 특성을 가지며 암 전이를 용이하게 하는 주요한 효소로 잘 알려져 있다. 본 연구에서는 항암후보물질인 disulfiram이 골 육종(U2OS), 신장암 (Caki-1) 및 자궁암 (Caski) 세포에서 MMP-2와 MMP-9의 효소활성 및 발현억제에 대해 조사하였다. MTT assay를 이용하여 disulfiram에 대한 암세포 viability 실험에서는 disulfiram이 암세포의 viability를 저해하였다. 또한 zymography, western blot 및 RT-PCR 등을 이용한 type Ⅳ collagenase의 활성 및 발현 실험에서 disulfiram은 type Ⅳ collagenase의 활성을 비롯하여 단백질 및 mRNA 발현을 억제시키는 것을 확인하였다. 따라서 disulfiram이 MMP-2와 MMP-9의 활성 및 발현 억제 기전을 통하여 골 육종, 신장암 및 자궁경부암 세포의 작용을 억제한다는 연구 결과는 disulfiram이 각종 악성종양의 침윤과 전이를 억제 또는 방지하기 위한 치료물질로서 임상에서 활용할 수 있는 가능성을 보여준다.