Although methotrexate(MTX) has been known to have many side effects, especially toxicity on the hemopoietic cells and the liver, it has been used as a potent anticancer drug and for the treatment of psoriasis or rheumatoid arthritis. The severity of hepatotoxicity varies from mild fatty change to chronic active hepatitis(CAH) and cirrhosis. We experienced two cases of MTXinduced CAH in patients with psoriasis, which prompted us to report in view of the absence of biopsy proven MTX hepatotoxicity in the Korean literature. Microscopically, the liver showed a distorted lobular architecture with portal fibrous expansion, piecemeal necrosis and bridging necrosis/fibrosis. The hepatic lobules revealed fatty changes of hepatocyte, focal hepatocytolysis, delicate collagen deposits along the space of Disse and the characteristically marked polyploid nuclear change of hepatocytes.
Biopsy

To evaluate the tissue expression rate and pattenr of HBsAg and HBcAg in tumors and peritumoral livers, an immunohistochemical study was undertaken on 47 surgically resected hepatocellular carcinomas(HCCs). The results are as follows. 1. Patient's sera were positive for HBsAg in 40 cases(85.1%). In the remaining 7 cases, the tumor and peritumoral liver expressed neither HBcAg nor HbSaG, suggesting that they were caused by other etiologies than hepatitis B virus. 2. The peritumoral liver had HBsAg and HBcAg in 95.0% and 27.5% among the 40 cases, respectively. But the tumor expressed HBsAg in 50.0% and HBcAg in none. 3. The expression of HBsAg within the tumor and both HBsAg and HBcAg in the peritumoral liver tended to be more frequent in the pretreated cases before surgery. 4. Edmondson-Steiner grade IV tumors revealed a lower expression rate of HBsAg than the low grade tumors(p<0.05). Incases with cirrhosis at peritumoral tissues, HBcAg was less frequently found than in those without cirrhosis. The majority of tissue HBsAg and HBcAg was represented as groups of positive cells. These results suggest that, during the development and progression of HCCs, the HBcAg containing cells are repeatedly removed and the HBcAg negative cells are selected, because cellular expression of HBcAg is the target of host immune response.
Carcinoma, Hepatocellular

No abstract available.
Colon* ; Colonic Neoplasms* ; Humans ; Vaccination*

No abstract available.
Beckwith-Wiedemann Syndrome*

OBJECTIVES: The transmission of medical information is currently a daily routine. Medical information needs efficient, robust and secure encryption modes, but cryptography is primarily a computationally intensive process. Towards this direction, we design a selective encryption scheme for critical data transmission. METHODS: We expand the advandced encrytion stanard (AES)-Rijndael with five criteria: the first is the compression of plain data, the second is the variable size of the block, the third is the selectable round, the fourth is the optimization of software implementation and the fifth is the selective function of the whole routine. We have tested our selective encryption scheme by C++ and it was compiled with Code::Blocks using a MinGW GCC compiler. RESULTS: The experimental results showed that our selective encryption scheme achieves a faster execution speed of encryption/decryption. In future work, we intend to use resource optimization to enhance the round operations, such as SubByte/InvSubByte, by exploiting similarities between encryption and decryption. CONCLUSIONS: As encryption schemes become more widely used, the concept of hardware and software co-design is also a growing new area of interest.
Medical Informatics

No abstract available.

Since it was reported that incipient enamel caries can be recovered, previous studies have quantitatively evaluated that enamel artificial caries have been remineralized with fluoride, showing simultaneously the increase of width of surface layer and the decrease of width of the body of legion. There is, however, little report which showed that remineralization could occur without fluoride. In addition, the observations on the change of hydroxyapatite crystals also have been scarcely seen. In this study, enamel caries in intact premolars or molars was induced by using lactic acidulated buffering solutions over 2 days. Then decalcified specimens were remineralized by seven groups of solutions using different degree of saturation (0.212, 0.239, 0.301, 0.355) and different pH (5.0, 5.5, 6.0) over 10 days. A qualitative comparison to changes of hydroxyapatite crystals after fracturing teeth was made under SEM (scanning electron microscopy) and AFM (atomic force microscopy). The results were as follows: 1. The size of hydroxyapatite crystals in demineralized area was smaller than the normal ones. While the space among crystals was expanded, it was observed that crystals are arranged irregularly. 2. In remineralized enamel area, the enlarged crystals with various shape were observed when the crystals were fused and new small crystals in intercrystalline spaces were deposited. 3. Group 3 and 4 with higher degree of saturation at same pH showed the formation of large clusters by aggregation of small crystals from the surface layer to the lesion body than group 1 and 2 with relatively low degree of saturation at same pH did. Especially group 4 showed complete remineralization to the body of lesions. Group 5 and 6 with lower pH at similar degree of saturation showed remineralization to the body of lesions while group 7 didn't show it. Unlike in Group 3 and 4, Group 5 and 6 showed that each particle was densely distributed with clear appearance rather than crystals form clusters together.
Bicuspid ; Dental Enamel* ; Durapatite* ; Fluorides ; Hydrogen-Ion Concentration* ; Lactic Acid* ; Microscopy, Atomic Force ; Microscopy, Electron, Scanning ; Molar ; Tooth

BACKGROUND/AIMS: HBV infection can be seen after organ transplantation. The presence of anti-Bs in serum means protection from HBV infection. If amino acids were mutated in 'a' determinant which was a common antigenic epitope of HBsAg, escape from humoral immunity can occur. Recently, in chronic HBV infected patients who received liver transplantation but reinfected by HBV, many authors reported mutations in 'a' determinant sequence. However, in renal transplantation, there were few reports about HBV infection and 'a' determinant mutation after transplantation. Therefore, we studied the incidence of HBV reinfection after renal transplantation and also tried to analyze 'a' determinant sequence in those patients. METHODS: We reviewed HBsAg-egative patients who received renal transplantation in our hospital, but turned HBsAg positive after transplantation. We selected two patients who were anti-Bs positive before transplantation but turned HBsAg positive after transplantation, and analyzed 'a' determinant of amino acid sequence of these patients. RESULTS: Among 1682 patients who were HBsAg negative before transplantation, 21 patients were turned HBsAg positive after transplantation. Among them, 6 patients were anti-Bs positive before transplantation. Sequence analysis of the 'a' determinant amino acid in two patients whose HBsAg turned positive after transplantation revealed no evidence of mutation in comparison with previously reported subtype 'a' determinant sequences. CONCLUSION: In renal transplantation, HBV could be reinfected in patients who had been anti-Bs positive before transplantation even without mutation in 'a' determinant region.
Amino Acid Sequence ; Amino Acids ; Hepatitis B Surface Antigens ; Humans ; Immunity, Humoral ; Incidence ; Kidney Transplantation* ; Liver Transplantation ; Organ Transplantation ; Sequence Analysis* ; Transplants ; United Nations

In gastrointestinal tract CMV has been implicated in inducing mucosal inflammatory and ulcerative lesions. More recently, increasing number of patients with CMV-associated gut lesions have been reported primarily in immunocompromised patients or occasionally in normal hosts. The colon is the most common site of the infection, although it might occur in other gastrointestinal tract such as esophagus, stomach, duodenum and terminal ileum. The diagnosis of CMV infection can often be difficult and must await serological conversian or viral cultures. (continue...)
Colon ; Cytomegalovirus* ; Diagnosis ; Duodenum ; Esophagus ; Gastrointestinal Tract ; Humans ; Ileum ; Immunocompromised Host ; Stomach ; Stomach Ulcer* ; Ulcer

BACKGROUND/AIMS: The prognosis of primary hepatocellular carcinoma is extremely poor because of its large size, portal vein thrpombosis, extrahepatic metastasis and underlying liver cirrhosis. The aim, of this study is to evaluate the usefulness of ultrasound screening test for early detection of hepatocellular carcinoma in high-ridk populations. METHODS: We analysed 119 patients who were diagnosed with hepatocellular carcinoma by ultrasonography screening test in Yonsei University Severance Hospital from the period of January 1990 to December 1996. RESULT: The mean follow-up duration to the diagnosis of hepatocellular carcinoma was 30 months (range 3-75). The number of patients with single lesion was 89(75%). The mean diameter of the tumor was 3.0 cm (range 1-10) , 82 patients (70%) had masses measured less than 3cm in diameter. The Number of patients with elevated serum alphafetoprotein level above 400ng/ml was 29(25%). The median survival was 28 months in screening group, significant compared with 7 months in control group (p<0.001). CONCLUSIONS: Ultrasound follow-up in high-ridk group of hepatocellular carcinoma mede it possible to detect small tumors in a high percentage of cases. This may lead to an increase in the number of potentially curable tumors and hence an increase in the overall survival rate. So ultrasound screening test is important in the high-ridk group of hepatocellular carcinoma.
Carcinoma, Hepatocellular* ; Diagnosis ; Early Diagnosis ; Follow-Up Studies ; Humans ; Liver Cirrhosis ; Mass Screening* ; Neoplasm Metastasis ; Portal Vein ; Prognosis ; Survival Rate ; Ultrasonography*