Scanning electron microscopic appearance of chronic ulcerative colitis with and without dysplasia.

This study was conducted to determine whether scanning electron microscopy of colonic mucosal biopsy specimens can help to detect dysplasia in patients with chronic ulcerative colitis. In the first phase of the study, using light microscopy as the standard for the diagnosis, the scanning electron microscopic appearance of specimens from patients with chronic ulcerative colitis and control patients was examined. Descriptive criteria were established to identify normal, atrophic, and dysplastic colonic mucosa. In the second phase, quantitative techniques were used to develop more objective criteria for the diagnosis of dysplasia in ulcerative colitis. Twenty-one coded colonic specimens from 11 patients were sequentially examined by scanning electron microscopy and by light microscopy. The three morphometric analyses performed on the surface epithelial cells were number of cells per unit area, number of microvilli per unit area, and percentage of microvilli with a normal width. The cell count and percentage of microvilli with a normal width were significantly reduced in the seven specimens with colonic dysplasia as compared with non-dysplastic tissues. Scanning electron microscopy may serve as an adjunct to light microscopy in the diagnosis of colonic dysplasia.

Localization of immunoreactive alkaline phosphatase in the rat small intestine at the light microscopic level by immunocytochemistry.

Monospecific antibody to purified alkaline phosphatase hs been used to localize alkaline phosphatase in the rat small intestine at the light microscopic level. Pieces of duodenum, jejunum, and ileum were removed from 2-, 9-, 12-, 18-, 21-, 26-day-old and adult wistar rats. They were fixed in Bouin's fluid and examined for the presence of alkaline phosphatase by th immunoperoxidase method. Slides were graded blindly for the intensity of staining. The localization of alkaline phosphatase by the immunoperoxidase method extends previous histochemical observations in several ways. First, diffuse cytoplasmic staining is present particularly in the opical portion of the villus and crypt epithelium. Second, staining for alkaline phosphatase is present on the brush border and in the apical portion of the deep crypt cells throughout the duodenum, jejunum, and ileum at the various ages tested. Third, in the adult rat distal ileum there is more staining on the brush border of the deep crypt epithelial cells than on the villus absorptive cells. These observations are consistent with the presence of a non-brush border alkaline phosphatase in all intestinal cells and with fan enzymatically inactive form of alkaline phosphatase in the deep crypt epithelium.

Effect of pentagastrin on rabbit stomach and small intestinal protein synthesis.

In an vitro organ culture system, we studied the effects of pentagastrin on rabbit fundic mucosa and small intestinal protein synthesis. The incorporation of [14C]leucine into protein was measured after 24 hr of incubation at 37 degrees C in a 95% oxygen-5% CO2 atmosphere. Biopsies were taken from the stomach, duodenum, jejunum, and ileum of rabbits fasted for 64 hr. Pentagastrin (0.5 microgram/ml) significantly increased protein synthesis in stomach explants at the 24-hr period but did not significantly increase protein synthesis in the duodenum, jejunum, or ileum explants. The results of these in vitro experiments may indicate that pentagastrin is not trophic for rabbit small intestine or, in contrast to its direct effect on the fundic mucosa, pentagastrin acts indirectly in the previously noted in vivo stimulation of intestinal protein synthesis.

Successful maintenance of suckling rat ileum in organ culture.

Ileum from rats 4, 9, 11, 12, and 15 days old can best be maintained for 24 hours in a system using Hanks' Balanced Salt Solution without fetal calf serum, at 25 degrees C and 21% O2. Suckling rat duodenum and jejunum were difficult to maintain well for 24 hours in this system or a variety of other systems that were tried. A temperature of 37 degrees C hastened deterioration of duodenum, jejunum or ileum. With ileum, 3H-thymidine and 14C-leucine were increasingly incorporated into DNA and protein over the 24-hour period. Light microscopy, as well as scanning and transmission electron microscopy, showed very good preservation of the ileum after 24 hours. The addition to the medium of hydrocortisone, 1 micron, and thyroxine, 0.01 micron, alone or in combination, did not change DNA or protein synthesis, or morphology, possibly because of the relatively short (24 hour) time period. Our organ culture system emphasizes the differences between suckling rat ileum and the rest of the intestine, and provides a new tool for evaluating, over a 24-hour period, the developing rat small intestine.