Rectal mucosectomy: a definitive approach to extensive hemangiomas of the rectum.

Major rectal bleeding may occur in children and adults who have extensive hemangiomatous involvement of the pelvis and rectosigmoid colon, as in the Kleppel-Trenaunay syndrome (KTS). Conventional surgical techniques such as bowel resection and colostomy have often been associated with large blood loss and/or incontinence. We have used a new approach to this problem utilizing rectal mucosectomy to eliminate the bleeding rectal mucosa and to preserve anal function. Four patients born with KTS eventually developed major rectal bleeding and were successfully corrected by this surgical approach. Two were females and two males. Ages ranged from 4 to 25 years at the time of surgery. The patients developed rectal bleeding leading to chronic anemia during the first decade of life. Rectal bleeding gradually increased requiring multiple transfusions (2 to 20 units) prior to surgery. Patient 1 underwent resection of the rectosigmoid colon, with rectal mucosectomy and endorectal coloanal anastomosis. The Nd:YAG laser was used on 3 occasions on the distal remaining rectal mucosa. Patients 2, 3, and 4 underwent sigmoid resection, transanal rectal mucosectomy, and a coloanal anastomosis, with minor YAG laser therapy in one patient. Blood loss during surgery was minimal. Follow-up ranged from 1.5 to 4 years. All have excellent sphincter control with no incontinence. No strictures or sepsis occurred following surgery. Rectal bleeding was eliminated in all 4 patients. This sphincter-saving approach should be considered in patients with extensive hemangiomas of the rectosigmoid colon because of its remarkable effectiveness and safety.

Translation of rat intestinal RNA yields two alkaline phosphatases.

After translation of total rat intestinal RNA, immunoprecipitation using monospecific antiserum against rat intestinal alkaline phosphatase yielded two polypeptides in the adult duodenum and jejunum (molecular masses 62 and 65 kDa). Immunoprecipitation of both bands was blocked by a single purified alkaline phosphatase. In the adult ileum and in the entire small intestine of suckling pups, only the 62 kDa translation product was found. After fat feeding, translated alkaline phosphatase increased by an amount proportionate to the increase in enzyme activity previously seen in the serum. A small fraction of nascent alkaline phosphatase was translocated into microsomal vesicles, producing peptides of 65 and 69 kDa. Tunicamycin-treated membranes demonstrated a different signal peptide for each translation product. N-Terminal sequencing of the translation products showed leucine residues at similar positions, but overlap with the mature protein sequence was not demonstrated. On the basis of these data, we propose the presence of two mRNAs encoding alkaline phosphatase in the rat intestine.

Biosynthesis of apolipoprotein C-III in rat liver and small intestinal mucosa.

We have examined the biosynthesis of rat apolipoprotein C-III in the small intestine and liver. The primary translation product of its mRNA was recovered from wheat germ and ascites cell-free systems. Comparison of its NH2-terminal sequence with the NH2 terminus of plasma high density lipoprotein-associated apolipoprotein C-III showed that apo-C-III was initially synthesized as a preprotein with a 20 amino acid long NH2-terminal extension: Met-X-X-X-Met-Leu-Leu-X-X-Ala-Leu-X-Ala-Leu-Leu-Ala-X-Ala-X-Ala. Co-translational cleavage of the cell-free translation product by signal peptidase generated a polypeptide with the same NH2 terminus as the mature protein (X-Glu-X-Glu-Gly-Ser-Leu-Leu-Leu-Gly-Ser-Met). Therefore, this apolipoprotein does not undergo post-translational proteolytic processing like two other high density lipoprotein-affiliated proteins, proapo-A-I and proapo-A-II. The mRNA encoding apolipoprotein C-III comprises 0.4% of the translatable RNA species in adult rat liver and 0.14% of the translatable RNA species in small intestinal epithelium. Acute fat feeding with a triglyceride meal resulted in a 2-fold increase in intestinal preapo-C-III mRNA accumulation but no change in the levels of preproapo-A-I mRNA. Thus, the acute response of the apo-A-I and C-III genes to triacylglycerol absorption differs.