Early carcinoma of the distal second part of the duodenum treated by wedge resection.

A case of early carcinoma of the distal second part of the duodenum, in a 74-year-old man, is presented. Endoscopic retrograde cholangiopancreatography was performed for diagnosis of a common bile duct stone. During this procedure, small elevated lesions were found incidentally in the distal second part of the duodenum, and the histologic examination of a biopsy specimen showed adenocarcinoma. The lesions were removed by wedge resection, and pathologic examination revealed duodenal carcinoma limited to the lamina propria. Although carcinoma of the duodenum, other than of the ampulla of Vater region, is very rare, it is sometimes possible to detect asymptomatic early tumors. However, this requires careful observation of the entire duodenal mucosa, including that of the distal duodenum, at duodenoscopy.

Effect of starving and refeeding on lipid metabolism in suncus.

We have previously reported that fatty liver is easily induced in a novel experimental animal, Suncus murinus (suncus) by withholding food, and that apolipoprotein B (apo B) is not actively synthesized in the liver. In the present paper we describe the effect of starving and refeeding on lipid and lipoprotein metabolism in suncus, in order to explore the mechanisms of induction of fatty liver by starving and of its improvement by refeeding. Starvation induced increase in triglyceride content and decrease in glycogen content of the liver. Although the glycogen content returned to the level before starvation at 12 h after refeeding, the triglyceride content decreased gradually but did not reach the prestarvation level even at 24 h after refeeding in suncus. Plasma lipids, glucose, and insulin levels were decreased by starvation and returned to the levels before starvation between 8 and 24 h after refeeding. On the other hand, the plasma levels of free fatty acid and ketone bodies were elevated significantly by starvation and decreased rapidly by refeeding. These responses to starvation and refeeding, except for the change in hepatic triglyceride, are in common with other experimental animals, suggesting that there are no abnormalities in glucose metabolism or in fatty acid metabolism in suncus. In conclusion, the fatty liver induced by starvation in suncus may be caused by impaired triglyceride transport out of the liver, for which apolipoprotein B is mostly responsible, as reported previously.

Effect of chylomicron remnants on apolipoprotein E synthesis in HepG2 cells.

The effect of chylomicron remnants (CM-R) on apolipoprotein (apo) E synthesis by HepG2 cells was studied. The accumulation rate of apo E in the medium was increased in cells incubated with CM-R (chylo-cells) compared with that in the control cells. However, the abundance of apo E mRNA was not greater in chylo-cells than in control cells. The time course of apo E accumulation in the medium showed that apo E increased in the chylo-cells linearly up to 24 hours, whereas it increased in the control cells linearly only up to 6 hours, when it reached a plateau. The results suggest that the secretion rate of apo E was not affected by incubation with CM-R, but that uptake of the newly secreted apo E by the cells may be depressed by incubation with CM-R. Autoradiography of newly synthesized apo E showed that chylo-cells produced much more "larger" apo E than did the control cells. Two-dimensional electrophoresis of the apo E newly synthesized by the chylo-cells showed that the larger apo E was slightly acidic even after treatment with neuraminidase. Pulse-chase labeling of apo E showed that the larger apo E was secreted by both control and chylo-cells equally and that the larger apo E was converted to regular apo E in the medium more effectively in control cells than in chylo-cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of serum lipoproteins from Suncus: a candidate animal model for abetalipoproteinemia.

We have previously reported that fatty liver was induced in a novel experimental animal, Suncus murinus (suncus), by 24-h fasting and that apolipoprotein B (apo B) was not actively synthesized in the liver. However, a faint signal of apo B mRNA was detected in the liver, suggesting possible synthesis of apo B. Small amounts of VLDL and LDL have been separated from suncus serum by ultracentrifugation. Electron microscopic study of the lipoproteins revealed the existence of small particles in VLDL. High performance liquid chromatographic analysis of the lipoproteins showed that the peaks of TG and cholesterol were mainly at the HDL fraction. These results indicate the existence of lipoproteins as small as HDL which were rich in TG and floated at the density of VLDL upon ultracentrifugation. Apolipoprotein analysis showed two bands of 500- and 200-kDa proteins in VLDL and LDL. Western blot analysis using antibody against the 500-kDa protein revealed reaction not only with suncus 500- and 200-kDa proteins but also with human apo B-100. In conclusion, a small amount of apo B is transported in the suncus serum as VLDL and LDL, although almost all lipid is packed in HDL-size particles.