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Soft-tissue masses with well-demarcated, dense and granular calcification were most frequently observed on plain radiographs and CT scans. T2-weighted MR images most clearly depicted a two-component structure composed of calcified and uncalcified areas, and enhanced MRI showed inhomogeneous enhancement in both areas. Although the sensitivity and specificity of these findings are unknown, they might be characteristic and have diagnostic value for this rare tumor.

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Periodic checkup by ultrasonography was conducted on patients with chronic liver diseases for early detection of hepatocellular carcinoma. In 19 months, a total of 2004 examinations were performed on a total of 660 cases (179 cases with liver cirrhosis in the compensatory stage, younger than 70 years; 481 cases with chronic hepatitis, aged 40 to 70 years for men and 50 to 70 years for women). Of the 660 cases, 22 HCC cases (3.3%) were detected and finally diagnosed by angiography and/or histologic examination. Four of those cases (18%) had a single nodule smaller than 1 cm in diameter, and 11 cases (50%) had a single nodule smaller than 2 cm. Surgical resection was performed on 12 cases (55%). In comparison with the control group (83 HCC cases not receiving any periodic checkup), the frequency of small liver cancer and the surgical resection rate in the study group were significantly higher. This examination system by periodic ultrasonography checkup of patients with chronic hepatic diseases was effective for early detection and permitted aggressive therapy of hepatocellular carcinoma.

To elucidate the natural history of colorectal polyps and to observe the influence of endoscopic polypectomy on the incidence of colorectal cancer, we conducted a retrospective cohort study of all patients who had undergone colonoscopic examination at the Center for Adult Diseases, Osaka, between April 1974 and December 1985. The study subjects consisted of a control group (760 non-polyp patients) and a polyp group (648 polyp patients, including 136 treated by polypectomy at the initial examination). These subjects were followed up until the end of 1987 by record linkage with the Osaka Cancer Registry's file to observe the occurrence of colorectal cancer. The O/E (observed/expected numbers derived from the general population) was 5.1 (95% confidence interval = 2.5-9.4) and 1.0 (0.1-3.6) for the polyp and control group, respectively. When subjects in the polyp group were categorized into polypectomy and non-polypectomy sub-groups, the O/E was 2.3 (0.1-12.6) and 8.0 (3.4-15.8) respectively. The relative risk of undergoing polypectomy to developing subsequent cancer was estimated at 0.3 (0.1-2.1). These results suggest an increased risk of developing cancer among polyp patients and the possibility of prophylactic effect of polypectomy against subsequent cancer. A large-scale and long-term follow-up study is required to confirm these findings.

a b s t r a c tNovel mesoporous silica sheets with surface amino-functional groups (sheet-NH 2 ) were prepared for the efficient adsorption of aqueous metal ions. The sheet-NH 2 were synthesized by a dual-templating process using Pluronic P123 and N-palmitoyl-l-alanine as templates. Two silicone regents were used to form the silica framework: tetraethoxysilane and 3-aminopropyltriethoxysilane. In the synthetic process, the as-prepared silicate was refluxed in ethanol to remove the organic templates remaining from the surface amino groups derived from APTES. The prepared sheet-NH 2 showed widths of several micrometres and small thicknesses of approximately 50 nm. The pore diameter, pore volume and BET surface area of sheet-NH 2 were determined by nitrogen adsorption-desorption isotherms to be 3.1 nm, 0.73 cm 3 g −1 and 189.9 m 2 g −1 , respectively. TEM, XRD, FT-IR and TG-DTA analysis demonstrated that the sheet material had a disordered mesoporous structure and contained organic chains. The adsorptions of aqueous zinc(II) and copper(II) metal ions were examined and compared with amino-functionalized conventional mesoporous silica (MCM-NH 2 ), calcined mesoporous silica sheets and silica beads with no porous structures. Notably, the sheet-NH 2 exhibited the highest adsorption of both zinc and copper ions among the examined materials. In addition, the metal ion sorption equilibrium data of sheet-NH 2 were fitted to the Langmuir isotherm model.

Dicer1, an essential component of RNA interference and the microRNA pathway, has many important roles in the morphogenesis of developing tissues. Dicer1 null mice have been reported to die at E7.5; therefore it is impossible to study its function in adult tissues. We previously reported that Dicer1-hypomorphic mice, whose Dicer1 expression was reduced to 20% in all tissues, were unexpectedly viable. Here we analyzed these mice to ascertain whether the down-regulation of Dicer1 expression has any influence on adult tissues. Interestingly, all tissues of adult (8–10 week old) Dicer1-hypomorphic mice were histologically normal except for the pancreas, whose development was normal at the fetal and neonatal stages; however, morphologic abnormalities in Dicer1-hypomorphic mice were detected after 4 weeks of age. This suggested that Dicer1 is important for maintaining the adult pancreas.