Third Of Small Intestine Research Articles

Loss of Chromosome 18 in Neuroendocrine Tumors of the Small Intestine: The Enigma Remains

Background/Aims: Neuroendocrine tumors of the small intestine (SI-NETs) exhibit an increasing incidence and high mortality rate. Until now, no fundamental molecular event has been linked to the tumorigenesis and progression of these tumors. Only the loss of chromosome 18 (Chr18) has been shown in up to two thirds of SI-NETs, whereby the significance of this alteration is still not understood. We therefore performed the first comprehensive study to identify Chr18-related events at the genetic, epigenetic and gene/protein expression levels. Methods: We did expression analysis of all seven putative Chr18-related tumor suppressors by quantitative real-time PCR (qRT-PCR), Western blot and immunohistochemistry. Next-generation exome sequencing and SNP array analysis were performed with five SI-NETs with (partial) loss of Chr18. Finally, we analyzed all microRNAs (miRNAs) located on Chr18 by qRT-PCR, comparing Chr18+/- and Chr18+/+ SI-NETs. Results: Only DCC (deleted in colorectal cancer) revealed loss of/greatly reduced expression in 6/21 cases (29%). No relevant loss of SMAD2, SMAD4, elongin A3 and CABLES was detected. PMAIP1 and maspin were absent at the protein level. Next-generation sequencing did not reveal relevant recurrent somatic mutations on Chr18 either in an exploratory cohort of five SI-NETs, or in a validation cohort (n = 30). SNP array analysis showed no additional losses. The quantitative analysis of all 27 Chr18-related miRNAs revealed no difference in expression between Chr18+/- and Chr18+/+ SI-NETs. Conclusion: DCC seems to be the only Chr18-related tumor suppressor affected by the monoallelic loss of Chr18 resulting in a loss of DCC protein expression in one third of SI-NETs. No additional genetic or epigenetic alterations were present on Chr18.

The development of arylsulphatase in the small intestine of the rat.

1. Arylsulphatase activity was measured in stomach, proximal and distal third of small intestine, colon, liver and kidney of foetal and neonatal Sprague-Dawley rats and Swiss mice, with nitrocatechol sulphate as substrate. 2. The specific activity in the distal small intestine, but not in the stomach, proximal small intestine or colon, increased about fourfold between 5 and 16 days after birth in both conventional and germ-free rats. 3. No comparable increase occurred in the distal small intestine of the mouse. 4. The specific activity of acid phosphatase in the distal small intestine of the rat rose only slightly when the arylsulphatase activity increased. 5. The pH optimum and Michaelis constant of arylsulphatase activity of the distal small intestine were similar for 1-day-old, 9-day-old and adult rats. 6. When extracts of distal small intestine of 1-day-old and 9-day-old rats were incubated together, the arylsulphatase activities were additive.

Studies on Schistocephalus solidus. II. Establishment and longevity in the definitive host

Schistocephalus solidus was found to mature in ducks ( Anas boschas), pigeons ( Columba livia), chickens ( Gallus domesticus), herring-gull ( Larus argentatus), blackheaded gull ( L. ridibundus), rats ( Rattus norvegieus), and hamsters ( Mesocricetus auratus). The age of the host was important in determining the percentage of worms to become established. Best results were obtained with 1–4-weeks-old ducks (over 50% established) and 2–5-weeks-old chickens (nearly 40% established). Examination of the distribution of worms in the intestine of the various laboratory hosts showed: (1) worms reach the intestine in 2–3 hours; (2) within the first 6 hours the worms occupy a specific region of the intestine which varies in the different hosts, e.g., posterior half of duck's intestine, anterior half of pigeon's, near the cecum in rat, and anterior third of small intestine in hamster; (3) in those hosts in which the worms occupy an anterior position there is evidence of an initial overshoot followed by an anterior migration. The length of life appears specific within a host species but differs greatly between species of host: approximately 18 days in hamsters, 6 in rats, 14 in chickens, 11 in ducks, and 10 days in pigeons. The following points are discussed: (1) the advantages and disadvantages in the use of the different laboratory hosts; (2) the problem of how Schistocephalus, which lacks hooks and suckers, can retain its position in the intestine; and (3) the factors which determine longevity, viz., senility changes, immunity reactions, and environmental risks. Present evidence suggests the longevity of Schistocephalus is limited by senility changes.