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In order to find a relationship between ductal hyperplasia and carcinoma of the pancreas, histological and histochemical examinations were made on pancreatic specimens of 1,174 autopsy patients with special attention to the age incidence of the former. Ductal hyperplasia was divided into 3 types; nonpapillary, papillary, and atypical hyperplasia. All three types of hyperplasia and ductal carcinoma showed a similar tinctorial property in mucous histochemistry. In general, atypical hyperplasia was seen in the pancreas having papillary hyperplasia which was found in the pancreas associated with nonpapillary hyperplasia. All three types of hyperplasia were apparently more frequent in cancerous pancreases than in non-cancerous ones. They were also more common in the head of the pancreas than in the body and tail. Age incidence also suggests a sequential change from nonpapillary hyperplasia through papillary and atypical ones to carcinoma.Cancer 43:1418-1428, 1979.HE GREAT MAJORITY of carcinomas of the T exocrine elements of the pancreas is of duct cell rigi in.^,^ The relationship of pancreatic duct hyperplasia to pancreatic carcinoma has been emphasized by Sommers et al.," because of the high incidence of ductal hyperplasia in carcinomatous pancreases. Cubilla and Fitzgerald3 also found a similar relation. However, following Birnstingl's report, they noted that there was obstruction to the pancreatic duct in most of their cases, a complicating factor in the assessment of ductal papillary hyperplasia. Birnstingl,2 in cases with a variety of acute and chronic nonpancreatic diseases and. no cancer of the pancreas, reported an incidence of 29% having hyperplastic columnar epithelium. It seems to be necessary for clarification of the relationship between ductal hyperplasia and carcinoma of the pancreas to reevaluate the age incidence of ductal hyperplasia in noncancerous pancreases. If ductal hyperplasia is a change preceding pancreatic carcinoma, it should appear in younger patients than those with pancreatic carcinoma. The aim of the present study is to find possible From the 2nd Department of Pathology, Nagoya University School of Medicine, Nagoya, Japan.Address for reprints: S. Komka, MD, T h e 2nd Department of Pathology, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466, Japan.Accepted for publication May 22, 1978. transition from ductal hyperplasia to carcinoma by histology and mucous histochemistry and to study age difference in incidence between ductal hyperplasia and pancreatic carcinoma. MATERIALS AND METHODSUsing autopsy cases at our laboratory, available routine microscopic sections of 1,174 pancreases of which 24 had infiltrating carcinoma were examined. Mostly one section, sometimes two or more sections, was prepared from one pancreas. Selected cases were stained with periodic acid Schiff/alcian blue pH 2.5 and high iron diamine/alcian blue pH 2.5.'*"Ductal hyperplasia was defined as ducts with large epithelial cells which are more than twice as tall as normal cells, because en...

The structure of the membrane skeleton on the cytoplasmic surface of the erythrocyte plasma membrane was observed in dried human erythrocyte ghosts by atomic force microscopy (AFM), taking advantage of its high sensitivity to small height variations in surfaces. The majority of the membrane skeleton can be imaged, even on the extracellular surface of the membrane. Various fixation and drying methods were examined for preparation of ghost membrane samples for AFM observation, and it was found that freeze-drying (freezing by rapid immersion in a cryogen) of unfixed specimens was a fast and simple way to obtain consistently good results for observation without removing the membrane or extending the membrane skeleton. Observation of the membrane skeleton at the external surface of the cell was possible mainly because the bilayer portion of the membrane sank into the cell during the drying process. The average mesh size of the spectrin network observed at the extracellular and cytoplasmic surfaces of the plasma membrane was 4800 and 3000 nm2, respectively, which indicates that spectrin forms a three-dimensionally folded meshwork, and that 80% of spectrin can be observed at the extracellular surface of the plasma membrane.