Mucous cell hyperplasia (MCH) has been considered an important precursor of pancreatic ductal carcinoma based on histological and molecular research, although various K‐ ras mutations rates are seen among cases with pancreatic carcinoma, chronic pancreatitis and normal pancreas, with a wide range of histological characters. To investigate the premalignant potential of MCH and the multicentricity of pancreatic carcinoma, we analyzed K‐ ras mutation at codon 12 in carcinoma foci of 82 cases of surgically‐resected pancreatic carcinoma [67 solid‐type carcinomas (SCs) and 15 ductectatic‐type carcinomas (DCs)], as well as in both MCH and carcinoma foci in 42 cases (30 SCs and 12 DCs), using an enriched polymerase chain reaction (PCR)‐enzyme linked mini‐sequence assay (ELMA). K‐ ras mutation was recognized in 85% (57/67) of SCs and 73% (11/15) of DCs, and multiple K‐ ras mutations in 12% (8/67) of SCs and in 20% (3/15) of DCs. Multiple K‐ ras mutations were also recognized in MCHs in 47% (14/30) of SCs and in 42% (5/12) of DCs. Moreover, the same sequence at K‐ ras codon 12 in MCH and carcinoma was identified in 76% (32/42) of carcinoma cases and it was more frequently recognized in hyperplasias with histological atypia (51%, 37 of 72 foci) than those without atypia (24%, 16 of 68 foci) ( P < 0.0007). These results further support the idea of multicentric carcinogenesis and premalignant potential of atypical hyperplasia in the human pancreas, although about half of the hyperplasias around carcinomas were not thought to be direct precursors.
We present a three-dimensional (3D) DRAM prototype, which is formed using oxide semiconductor FETs (OSFETs) monolithically stacked on a Si CMOS.The OSFETs are composed of a one-layer planar FET and two-layer vertical FETs (VFETs).The 1T1C memory cells in the VFET layers and a primary sense amplifier in the planar FET layer, which are formed using heterogeneous OSFETs, provide various circuit functions in the DRAM.The operation of the 3D DRAM in a 1-Mbit memory array is demonstrated for the first time.The results show that the proposed DRAM operates with read and write times of 60 ns and 50 ns, respectively.The leakage current of the memory cell is extremely low (comparable to an 2.2 10 -19 A/cell at 85C), indicating that over 99 of the data are retained in the memory array after one hour at 85C without refresh.
The presence of myocardial involvement is rare in benign Duchenne type of progressive muscular dystrophy (Becker's muscular dystrophy). We describe two brothers suffering from Becker's muscular dystrophy, both of whom presented with dilated cardiomyopathy. The first case is a 39-year-old male who had suffered from gait disturbance from the age of 17. When 37 years old, he was found to have heart disease. When he first came to our hospital, pseudohypertrophy of the calves was present. Chest radiography, electrocardiogram, ultrasonocardiography and clinical feature indicated Becker's muscular dystrophy with dilated cardiomyopathy. The second case is the younger brother of the 37-year old male. He suffered from leg weakness. He came to our hospital with the chief complaint of discomfort of the anterior chest. Pseudohypertrophy of the calves was present. Chest radiography, electrocardiogram, ultrasonogram indicated dilated cardiomyopathy.
We studied the effects of transforming growth factor-beta1 (TGF-beta1) on guinea pig gastric mucous cells, cultured in serum-free conditions. Electron microscopy showed that most cells were pre-pit cells, characterized by the presence of a few secretory granules scattered in the cytoplasm. Epidermal growth factor (EGF) stimulated cell growth, [3H]glucosamine uptake, and accumulation of mucus granules positive for galactose oxidase-Schiff reaction. This EGF-induced maturation into pit cells was confirmed morphologically by the appearance of uniformly dense ovoid or spherical mucus granules packed in the ectoplasm. Western blotting with an antiphosphotyrosine antibody showed that TGF-beta1 did not inhibit the EGF-initiated tyrosine phosphorylation of the EGF receptor. Northern blotting with cDNA probes for c-fos and c-myc demonstrated that TGF-beta1 did not affect the EGF-induced expression of the transcripts. However, TGF-beta1-treated cells did not replicate and remained in an immature stage, even in the presence of EGF, suggesting a potential role of TGF-beta1 in the regulation of proliferation and differentiation of a pit cell lineage in vivo.
