predominantly right-sided, consistent with studies showing that mortality of right-sided lesions is unaffected by screening.Adnab-9 stool testing may identify patients needing more intensive surveillance.Adnab-9-defined Field Effects: High-Risk Patients with Normal Colonoscopy * Most of significant neoplasia were left-sided.

Mie theory has been used to describe the reduced scattering coefficient from a model that extracts optical properties from a reflectance spectrum. Preliminary results are presented from normal and inflamed colon mucosa.

In H508 human colon cancer cells, cholinergic ligands activate M 3 muscarinic receptors (M 3 R), resulting in pro-proliferative signaling and cell proliferation (Cancer Res 63:6744, 2003).Our previous work indicates that proliferation of H508 cells is attenuated by incubation with non-selective and selective M 3 R inverse agonists and choline transport inhibitors.Cell proliferation is enhanced by incubation with acetylcholinesterase inhibitors.These findings suggested to us that endogenous acetylcholine (ACh) production by H508 cells may regulate basal cell proliferation.To address this possibility: (1) We used RT-PCT to examine colon cancer cell expression of choline acetyltransferase (ChAT), an enzyme required for ACh synthesis, and (2) We used high performance liquid chromatography with electrochemical detection (HPLC-ED) to measure both cell content of choline, a required substrate for ACh synthesis, and the amount of ACh released into the cell culture medium.ChAT expression (100-bp product) in H508 cells was identified by real-time RT-PCR using exonspanning primers.Choline (14-62 µM) and ACh (80-650 nM) were reproducibly detected in the cell culture medium (~2X10 6 cells/ml).Whereas detection of ACh required preincubation of cells for 24-48 hr with an inhibitor of acetylcholinesterase (0.5 mM eserine), this agent had no impact on detection of choline.The amount of ACh released into the medium was dependent on the number of cell passages; this also did not impact choline concentration.Even in the presence of eserine, ACh was not detected in cell extracts suggesting rapid hydrolysis of un-released intracellular ACh or amounts below the limit of detection by HPLC-ED (50 nM).Choline (10-22 µM) was readily detected in cell extracts.Because normal colon epithelial cells express and most colon cancer over-express M 3 R, we considered the possibility that endogenous ACh production by cancer cells In Vivo is a mechanism of autocrine growth regulation.To address this, we examined ChAT expression in human colon surgical specimens (colon cancer, N=10; normal colon, N=5).Using immunohistochemistry, cytoplasmic epithelial cell expression of ChAT was detected in all 10 cancer specimens, but not in normal colon.In conclusion: (1) A cell line derived from a human cecal adenocarcinoma contains abundant choline, expresses ChAT, and releases ACh into the cell culture medium.(2) Whereas ChAT was not detected in normal colon epithelial cells, cancer tissue resected from 10 patients expressed abundant ChAT.(3) ACh may be an autocrine growth factor for colon cancer.Regulation of ChAT expression and ACh production in colon cancer warrants further investigation.

In H508 human colon cancer cells, cholinergic ligands activate M 3 muscarinic receptors (M 3 R), resulting in pro-proliferative signaling and cell proliferation (Cancer Res 63:6744, 2003).Our previous work indicates that proliferation of H508 cells is attenuated by incubation with non-selective and selective M 3 R inverse agonists and choline transport inhibitors.Cell proliferation is enhanced by incubation with acetylcholinesterase inhibitors.These findings suggested to us that endogenous acetylcholine (ACh) production by H508 cells may regulate basal cell proliferation.To address this possibility: (1) We used RT-PCT to examine colon cancer cell expression of choline acetyltransferase (ChAT), an enzyme required for ACh synthesis, and (2) We used high performance liquid chromatography with electrochemical detection (HPLC-ED) to measure both cell content of choline, a required substrate for ACh synthesis, and the amount of ACh released into the cell culture medium.ChAT expression (100-bp product) in H508 cells was identified by real-time RT-PCR using exonspanning primers.Choline (14-62 µM) and ACh (80-650 nM) were reproducibly detected in the cell culture medium (~2X10 6 cells/ml).Whereas detection of ACh required preincubation of cells for 24-48 hr with an inhibitor of acetylcholinesterase (0.5 mM eserine), this agent had no impact on detection of choline.The amount of ACh released into the medium was dependent on the number of cell passages; this also did not impact choline concentration.Even in the presence of eserine, ACh was not detected in cell extracts suggesting rapid hydrolysis of un-released intracellular ACh or amounts below the limit of detection by HPLC-ED (50 nM).Choline (10-22 µM) was readily detected in cell extracts.Because normal colon epithelial cells express and most colon cancer over-express M 3 R, we considered the possibility that endogenous ACh production by cancer cells In Vivo is a mechanism of autocrine growth regulation.To address this, we examined ChAT expression in human colon surgical specimens (colon cancer, N=10; normal colon, N=5).Using immunohistochemistry, cytoplasmic epithelial cell expression of ChAT was detected in all 10 cancer specimens, but not in normal colon.In conclusion: (1) A cell line derived from a human cecal adenocarcinoma contains abundant choline, expresses ChAT, and releases ACh into the cell culture medium.(2) Whereas ChAT was not detected in normal colon epithelial cells, cancer tissue resected from 10 patients expressed abundant ChAT.(3) ACh may be an autocrine growth factor for colon cancer.Regulation of ChAT expression and ACh production in colon cancer warrants further investigation.