Use of structural equation modeling to test the construct validity of a case definition of Gulf War syndrome: invariance over developmental and validation samples, service branches and publicity.

To attempt to replicate the syndrome-like structure identified by exploratory factor analysis of symptom reports from 249 Gulf War veterans of a Naval reserve battalion (the developmental sample), we administered Haley's original symptom questionnaire to 335 Gulf War veterans who served primarily in active-duty US Army units living in North Texas (the validation sample). On the basis of recently validated goodness-of-fit criteria (SRMRor=0.95), a structural equation model (Model 1) with four symptom scales loading on each of three first-order latent syndrome factors fit both the developmental and validation samples well and was invariant across both samples. Additional models validated a higher-order latent factor (a single Gulf War syndrome) explaining the variances and covariances of the first-order factors, four additional symptom scales loading on the higher-order factor, and four possible secondary factor loadings that also fit the data well. All structural models were invariant across cohorts of the validation sample surveyed before and after intense publicity following publication of the case definition. These findings suggest that the apparent syndrome structure of a single Gulf War syndrome with three variants may be found widely and justify a confirmatory sample survey of Gulf War-era veterans.

Effect of spermine administration on pancreatic maturation in unweaned rats.

The effect of oral administration of spermine on pancreatic maturation was investigated in the suckling rat. The treatment consisted of 0.3-0.4 mmol spermine kg-1 body weight given orally once a day for 3 days starting at day 11 after birth. Spermine administration does not adversely affect the growth of the pancreas (wet weight, protein and DNA contents remain unchanged). The proliferating cell nuclear antigen (PCNA) index decreases significantly in spermine-treated rats, indicating that spermine slows down the proliferation rate of the organ. The enzymatic activities of trypsin, chymotrypsin and alpha-amylase are increased significantly in the pancreas of spermine-treated rats. The morphology of the organ seems affected as shown by hematoxylin-eosin staining: a cytoplasm indicative of higher synthetic activity is visible after spermine treatment. We conclude that spermine treatment of unweaned rats can induce precocious biochemical and morphological maturation of the exocrine pancreas, pushing the organ forward in the process of differentiation (closer to the adult stage).

Early weaning induces jejunal ornithine decarboxylase and cell proliferation in neonatal rats.

Increased ornithine decarboxylase (ODC) activity is associated with rapid cell proliferation in many cell types. The cellular effects of early weaning on intestinal development are not well established. To investigate whether ODC is involved in intestinal growth after early weaning, we precociously weaned suckling rats on postnatal d 15 and followed through d 21 (6 d after early weaning). Age-matched suckling pups served as controls. Rat pups were killed 1, 2, 3 and 6 d after early weaning and jejunal mucosa was assayed for ODC and sucrase activities, and protein and DNA contents. Jejunal cell proliferation was monitored by bromodeoxyuridine immunohistochemistry. Elevated jejunal ODC activity 1 d after early weaning was the earliest cellular event that was detected in the current study. ODC activity peaked at d 3 (about 15-fold greater than age-matched unweaned suckling controls). Sucrase activity was elevated at d 2 after weaning and peaked at d 3 (about 10-fold greater than controls). Greater bromodeoxyuridine immunostaining in early weaned rats occurred on d 3. Protein and DNA contents were greater in jejunal mucosa of early weaned rats at d 6. Serum corticosterone levels were elevated on d 1 and d 2 after early weaning compared to controls. To explore whether the intake of nonpurified diet played a role, we also compared the induction of jejunal ODC activity in early weaned pups and pups that were food-deprived for 1 d. ODC activity was not greater in the food-deprived group compared to suckling controls while the early weaned group had 6-fold greater activity 1 d after early weaning. Early weaning stimulates jejunal cell proliferation and differentiation. The temporal sequence of increased ODC activity followed by increases in other growth variables suggests that the induction of ODC activity may act as an early marker of intestinal growth during early weaning.

Zollinger-Ellison syndrome, acromegaly, and colorectal neoplasia.

Zollinger-Ellison syndrome (ZES) and acromegaly are two hypersecretory states in which colorectal neoplasia has been described, but the incidence in the former condition may not be increased. We describe four patients with colorectal neoplasia associated with the ZES and review other published cases. Tissue ELISA with Adnab-9 antibody, a putative colorectal cancer risk marker, from a patient with ZES and from seven patients with acromegaly was compared to 13 controls at average risk for colorectal neoplasia. The patient with ZES without detectable colonic neoplasia and seven patients with acromegaly had increased binding of Adnab-9 in the colonic mucosa by ELISA. The difference was significant for the acromegaly patients compared to the controls (p < 0.05). The accumulated 34 instances of colorectal neoplasia in ZES patients suggests that this association may not be rare. Adnab-9 expression, detectable in both ZES and acromegaly, may reflect predisposition to colorectal neoplasia in both hyper-secretory states. Therefore, while a basis for association of colorectal neoplasia and hypergastrinemia exists, the clinical data are not compelling enough to warrant surveillance of patients with ZES. To resolve this problem, more definitive case control studies should be conducted.

Effect of thyroxine on pancreatic digestive enzymes and ornithine decarboxylase gene expression in neonatal rats.

BACKGROUND: Thyroxine has been shown to play a role in the development of exocrine pancreatic enzymes in neonatal rats. METHODS: To further evaluate the regulatory mechanisms for thyroxine in pancreatic development, we examined the changes in the expression of pancreatic enzymes (amylase and trypsinogen) and ornithine decarboxylase (ODC) genes following daily injection of thyroxine for 5 and 10 days to neonatal rats (5 days old). RESULTS: Total pancreatic proteins and DNA contents as well as the activity of ODC and exocrine enzymes were significantly increased after 5 and 10 days of thyroxine treatment. These increases were associated with parallel alterations (to three to fourfold rise) in steady-state mRNA levels of both amylase and trypsinogen. In contrast, thyroxine only produced a 57-68% increase in steady-state ODC mRNA levels. CONCLUSIONS: These data suggest that thyroxine stimulated the express of amylase and trypsinogen genes partly due to increased transcriptional rate and/ or decreased mRNA turnover. Thyroxine also stimulated ODC gene expression. However, the stimulatory mechanisms may involve transnational or posttranslational regulation of ODC and are independent of thyroxine effects.

Prevention of gastrointestinal cancer--the potential role of NSAIDs in colorectal cancer.

Gastrointestinal cancers are among the leading sites of cancer and leading causes of cancer-related deaths. Gastrointestinal cancers are often at an advanced stage at the time of diagnosis, and are highly resistant to non-surgical therapy. Thus early diagnosis and prevention are approaches that are under active investigation. Screening and surveillance are considered secondary prevention. Primary prevention is the use of dietary or environmental modification or chemopreventive agents. This written review will emphasize the potential role of acetylsalicylic acid and other non-steroidal anti-inflammatory drugs (NSAIDs) in the prevention of gastrointestinal cancer, and specifically colorectal cancer. Cell culture and animal studies have shown that NSAIDs possess anti-proliferative and anti-neoplastic effects. Recent epidemiologic surveys also suggest that individuals who regularly take NSAIDs, particularly acetylsalicylic acid, have about a 50% decrease in colorectal cancer incidence and mortality. However, in the only interventional trial of aspirin (and beta-carotene), a retrospective analysis had inadequate statistical power to demonstrate any protective effect against colorectal cancer. About a dozen small prospective intervention studies have been done in a total of about a hundred patients with familial adenomatous polyposis to test the efficacy of NSAIDs, particularly sulindac. All human trials have shown substantial partial and some complete regression of colorectal and perhaps also duodenal adenomatous polyps. But virtually all patients had regrowth of adenomatous polyps after sulindac was stopped. In addition, sulindac and other NSAIDs result in occasional adverse events such as gastrointestinal bleeding. Thus sulindac cannot be recommended for routine use outside of a study setting. One valid current approach to the prevention of gastrointestinal cancer, and colorectal cancer in particular, is the adoption of a healthy lifestyle and appropriate screening and surveillance. Screening and surveillance guidelines have been developed by several public agencies and their recommendations should be adopted. In addition, we should adopt a healthy lifestyle and diet, which consists of low fat ( < 30% to total calories), and high fiber (> 3 daily servings of fruits/vegetables), with the avoidance of red meats ( < 3 weekly servings) and alcohol ( < 2 drinks daily), and the absolute avoidance of tobacco smoking.

Effect of beta-carotene supplementation on indices of colonic cell proliferation.

BACKGROUND: Epidemiologic studies have shown that consuming foods containing beta-carotene is associated with a decreased incidence of colon cancer. The validity of this association has recently been questioned. It is not known if the rate of colonic cell proliferation differs among individuals with or without a history of colonic polyps or cancer and if proliferation changes in response to beta-carotene. PURPOSE: This study was intended to (a) determine whether differences exist in colonic cell proliferation in individuals with and without prior colonic polyps or tumors, (b) demonstrate that beta-carotene accumulates in colonic mucosa following dietary supplementation, and (c) determine whether mucosal beta-carotene accumulation influences colonic cell proliferation. METHODS: Subjects were enrolled in the phase I study from June 1991 until February 1994. The participants included 20 individuals (11 males and nine females, aged 62.3 +/- 8.9 years [means +/- SD]) with normal colons (as judged by recent colonoscopy), 40 (24 males and 16 females, aged 59.6 +/- 10.1 years) with a history of colonic polyp(s), and 41 (30 males and 11 females, aged 67.2 +/- 9.7 years) with prior colon cancer. The subjects in the last two groups consumed either 30 mg of beta-carotene or placebo each morning for 3 months. This dose of beta-carotene has no known toxic effects, but it can increase the serum level by approximately 10-fold. beta-carotene concentration in serum and colonic tissue was quantitated by high-pressure liquid chromatography in samples collected before and after supplementation with beta-carotene or placebo. Cellular proliferation was assessed on the basis of tissue ornithine decarboxylase activity, urinary polyamine excretion, and proliferating cell nuclear antigen expression. The differences in colonic cell proliferation parameters due to beta-carotene supplementation, within and among different groups, were evaluated by the Wilcoxon matched-pairs signed ranked test and the Mann-Whitney test, respectively. All statistical tests were two-sided. RESULTS: Colonic cell proliferation did not differ in samples obtained from individuals with and without prior colonic polyp(s) or cancer. beta-carotene concentrations in serum and colonic tissue were significantly increased in groups receiving beta-carotene (P < .001). However, cell proliferation did not differ, as judged by any of the three measures, among samples from all experimental groups collected before and after supplementation with beta-carotene. CONCLUSIONS: Dietary supplementation with beta-carotene for a period of 3 months does not alter colonic cell proliferation in individuals with a history of colonic polyps or cancer. IMPLICATIONS: The mechanism by which beta-carotene might reduce colon cancer incidence does not appear to involve or result in a change in cell proliferation in the normal colonic mucosa as studied in individuals with a history of colonic polyps or cancer.

Diagnosis and therapy of hereditary polyposis syndromes.

The hereditary polyposis syndromes include the adenomatous polyposis syndromes (familial adenomatous polyposis and Gardner syndrome, and Turcot syndrome) and the hamartomatous polyposis syndromes (Peutz-Jeghers syndrome, juvenile polyposis, and Cowden's disease). The adenomatous polyposis syndromes are characterized by numerous adenomatous polyps throughout the entire colon and a spectrum of extracolonic manifestations; they invariably progress to colorectal cancer without appropriate intervention. The hamartomatous polyposis syndromes are characterized by diffuse intestinal or colonic hamartomatous polyps, such as juvenile polyps. Although hamartomatous polyps have virtually no malignant potential, the hamartomatous polyposis syndromes are associated with increased risk of cancer, both within and outside the small intestine and the colon. Diagnosis of symptomatic polyposis is by colonoscopy, but in presymptomatic screening of familial adenomatous polyposis, genetic testing can be effective, and it is becoming increasingly available though research laboratories. Management involves treatment of affected individuals, counseling of patients and their families, screening of at-risk individuals, and surveillance of affected patients for extracolonic cancers. Treatment of adenomatous polyposis is primarily colectomy during the second or third decade. For the hamartomatous polyposis syndromes, surveillance for early cancers and their excision remain the only practical, although not totally satisfactory, approaches.

Effect of 1,19-bis(ethylamino)-5,10,15-triazanonadecane on human tumor xenografts.

The polyamine analogue 1,19-bis(ethylamino)-5,10,15-triazanonadecane (BE-4-4-4-4), 5 mg/kg i.p., was given twice daily on days 0-3 and 7-10 (cycle 1) to nude mice with human malignant gliomas (SF-767 and U-87 MG), lung adenocarcinoma (A549), and colon carcinomas (HCT116 and HT29). A second cycle of drug was given to mice with SF-767 and A549 tumors on days 42-45 and 49-52. The maximum animal weight loss varied between 4 and 12%, which was observed 10-15 days following the initiation of treatment, but no overt toxic reactions were noted. The SF-767 brain tumors were extremely responsive to BE-4-4-4-4 alone (3 of 8 complete regressions after 2 cycles); however, the growth of the U-87 MG brain tumor was only slightly inhibited by BE-4-4-4-4 treatment. There was significant inhibition of tumor growth after treatment with one cycle of BE-4-4-4-4 in animals carrying the A549, HCT116, and HT29 tumors. At day 73, the growth of the A549 tumor was inhibited by 78 and 89% following one or two cycles of BE-4-4-4-4, respectively. The mitotic index of A549 tumors was 18 times greater in control mice than in those treated with BE-4-4-4-4 for one or two cycles 99 days after initiation of treatment. 1,3-Bis(2-chloroethyl)-1-nitrosourea (BCNU) was given to mice carrying the U-87 MG or A549 tumors on day 4 (cycle 1) and day 46 (cycle 2) in the maximal tolerated dose of 50 mg/kg for BCNU alone and 40 mg/kg for BCNU plus BE-4-4-4-4. BCNU alone significantly inhibited the growth of U-87 MG tumors but not the growth of A549 tumors. Treatment with the combination of BCNU and BE-4-4-4-4 was significantly better than BCNU alone for A549 tumors and better than BE-4-4-4-4 alone for U87 tumors. However, in both animal groups treated with the combination, there was a significant weight loss, which was not observed for animals treated with either agent alone. These data suggest a role for BE-4-4-4-4 in the treatment of brain, lung, and colon tumors.

Neuropeptide Y (NPY) enhances proliferation of human colonic lamina propria lymphocytes.

Neuropeptide Y (NPY) is one member of a family of peptides with a wide range of physiological effects on the CNS, cardiovascular, and respiratory systems. NPY is widely distributed throughout the peripheral and central nervous systems. It has also been found within the colon, liver and gallbladder in close anatomic proximity to the mucosal immune system. In this study, we investigated the effect of NPY on human gut mucosal immune function. We examined colonic lamina propria lymphocyte (LPL) proliferation by measuring DNA synthesis, ornithine decarboxylase (ODC) activity, and polyamine biosynthesis. NPY enhanced ODC activity and polyamine biosynthesis in Con A-stimulated LPL, and enhanced thymidine incorporation into Con A-stimulated LPL but not into monocyte-depleted LPL. Moreover, exogenous IL1-beta partially restored NPY's stimulatory effect on monocyte-depleted LPL DNA synthesis. Our results demonstrate that NPY enhances human colonic LPL proliferation and that this effect is partially IL1-beta dependent. Our data also suggest that NPY's effect may be mediated via polyamine biosynthesis. We postulate that the NPY may have an important impact on human mucosal immune function.

Rolling review: gastrointestinal malignancy.

The chemotherapy of gastrointestinal malignancies remain mostly investigational, although several adjuvant protocols in colorectal cancer and anal cancer are beginning to be accepted as standards against which newer regimens are to be compared. Chemotherapy regimens are best understood and appreciated with a basic understanding of cancer biology, tumour cell kinetics, and drug toxicities. An appreciation of chemotherapy-induced toxicity and an awareness of their management will help the gastroenterologist be an active participant in the multidisciplinary team caring for the patient with gastrointestinal malignancies.

Mucosal origin and shedding of an early colonic tumor marker defined by Adnab-9 monoclonal antibody.

Recent attention has been drawn to the diagnostic potential of tests based on shed colonic tumor markers. Adnab-9 monoclonal antibody raised against neoplastic, potentially premalignant colonic adenomas recognizes a marker in colonic effluent or tissue which correlates with the presence of tumors or risk of colorectal cancer. The origin of this antigen and optimal collection of colonic effluent were investigated by enzyme-linked immunosorbent assay and Western blotting. Mean Adnab-9 binding in effluent samples from colorectal cancer patients even after resection is high as compared with that in normal subjects (P < 0.05). Effluent samples are best collected in the morning hours. Antigen proteolysis may be significant depending on the site and timing of effluent collection, but breakdown products are reactive. Tissue and effluent Adnab-9 binding at any one anatomic site of collection appear to correlate (r = 0.88, P = 0.01). The Adnab-9 antigen is constitutively expressed at low levels throughout the distal bowel and localized to the deepest regions of the mucosal crypts. Other than meconium, no significant levels of binding are found in other body fluids. This antigen is specific for the gastrointestinal tract, its binding in conveniently collected effluent samples correlates with tissue content, and the antigen is constitutively expressed in the crypts of the distal small bowel and colonic mucosa.

Analysis of ODC and c-myc gene expression in hepatocellular carcinoma by in situ hybridization and immunohistochemistry.

We quantitated mRNA and protein for ornithine decarboxylase (ODC) and c-myc in formalin-fixed liver sections from 25 specimens of hepatocellular carcinoma (HCC) and seven normal livers by a non-radiolabeled in situ hybridization technique and immunohistochemistry. This non-radioactive in situ hybridization technique was highly specific, with virtually no background, and permitted quantitative analysis based on optical density. Reaction products were quantitated with computer-assisted microdensitometry. Samples were classified as normal, adjacent uninvolved, cirrhosis, well-differentiated HCC, and poorly-differentiated HCC. There was a progressive increase in all four parameters measured, ODC mRNA and protein, and c-myc mRNA and protein, from normal, to adjacent uninvolved liver, to cirrhosis, to well-differentiated HCC, to poorly-differentiated HCC. The sole exception was that ODC mRNA was lowest in cirrhosis. The patterns of ODC and c-myc gene expression are similar in HCC. The quantitative detection of ODC mRNA, c-myc mRNA, and their protein products in hepatocellular carcinoma and cirrhosis by in situ hybridization and immunohistochemical techniques may have a potential role in the study of hepatocarcinogenesis and in the diagnosis of hepatocellular carcinoma.

beta-Carotene inhibits rectal mucosal ornithine decarboxylase activity in colon cancer patients.

Colonic adenocarcinoma affects approximately 6% of adults in many Western countries. beta-Carotene (BC), a safe, inexpensive, and widely available compound, has been proposed as a cancer chemopreventive agent. To evaluate whether BC shows promise as an inhibitor of colonic carcinogenesis, we studied 20 male subjects who had previously undergone resection of colonic adenocarcinoma. Each subject received beta-carotene, 30 mg orally, daily for 6 months. Rectal mucosa was sampled at multiple intervals prior to, during, and following BC administration. Mucosal ornithine decarboxylase (ODC) activity and serum and mucosal BC concentrations were determined at each interval. ODC activity was inhibited by 44% (P < 0.05) and 57% (P < 0.01) after 2 and 9 weeks, respectively, of BC administration and remained low compared with baseline even 6 months following discontinuation of BC. Serum and mucosal BC concentrations increased as expected during BC administration and remained elevated for 6 months following BC discontinuation. The demonstrated inhibition of rectal mucosal ODC activity in these patients with resected colon cancer suggests that BC may prove useful as a cancer chemopreventive agent.

Transformation of NIH/3T3 cells by ornithine decarboxylase overexpression.

Ornithine decarboxylase (ODC) plays a rate-limiting role in polyamine biosynthesis and is intimately associated with cell proliferation and function. Although elevated levels of ODC mRNA, protein, and enzyme activity are consistently detected in transformed cells and tumors, the question remains as to whether ODC gene overexpression has a causative role in tumorigenesis. We have stably transfected NIH/3T3 fibroblasts with an expression construct containing human ODC complementary DNA under transcriptional control of the human beta-actin promoter. Cells transfected with the beta-actin/ODC DNA construct, designated NODC cells, and control transfectants, termed NLK cells, were analyzed for ODC gene expression and cell growth characteristics. ODC activity and mRNA levels were elevated 3-6-fold in NODC cells relative to NLK cells. NODC cells, in contrast to NLK control cells, are not contact inhibited, exhibit anchorage-independent growth, cycle more rapidly, and induce tumors in nude mice more efficiently and rapidly. These results directly establish a causative role for the misregulation of ODC gene expression in the acquisition of a transformation phenotype and provide a model to examine the interaction of ODC and other gene products in neoplastic development.

Inhibition of ornithine decarboxylase activity decreases polyamines and suppresses DNA synthesis in human colonic lamina propria lymphocytes.

Ornithine decarboxylase (ODC) and the polyamines are essential for cell proliferation in a variety of cells including lymphocytes. In this study, we investigated the potential role of ODC and polyamines in human colonic lamina propria lymphocytes (LPL) compared to peripheral blood lymphocytes (PBL). Our results show that con A stimulation of LPL and PBL was associated with marked increases in ODC and polyamines. The specific inhibitor of ODC, alpha-difluoromethylornithine (DFMO), resulted in a complete inhibition of ODC activity and depletion of putrescine, spermidine and spermine levels. DFMO also suppressed DNA synthesis of LPL and PBL by up to 48% and 62% respectively. This antiproliferative effect was reversed by adding back the polyamines putrescine (1 mM), spermidine (10 microM) or spermine (10 microM) to the culture medium. We conclude that ODC and the polyamines are important for human LPL proliferation, and hence may play a role in human mucosal immune function.

A defined collagen substrate and nutrient diffusion gradient culture system allows human colon cancer cells to assume a more differentiated phenotype.

A culture system is presented in which a biologically more relevant substrate in the form of a collagen membrane and a biologically more relevant diffusion gradient system for nutrient delivery to the cells are provided. Five established human colon cancer cell lines (Caco-2, DLD-1, Widr, HCT 116 and HCT 8) were cultured in this system and three of them showed increased differentiation compared with the same cells cultured on the usual cell culture substrates of plastic and glass and with cells grown in an anchorage-independent manner. Caco-2 cells grow on plastic as a monolayer of large pleomorphic cells with scant mucin production. When cultured in a gradient diffusion system in a sandwich of type I/IV collagen the Caco-2 cells showed the highest degree of morphological and biochemical differentiation as evidenced by cellular alignment, glandular formation and mucin production. Similarly DLD-1 cells exhibited the greatest degree of morphological and biochemical differentiation in a gradient system in a type I/IV collagen sandwich. HCT 116 and HCT 8 cells, however, showed little change in differentiation phenotype under any of the 11 culture conditions tested. Widr cells grew in a type I/IV collagen sandwich in a gradient diffusion system as multilayered sheets of cells with intercellular spaces, suggestive of a moderate increase in differentiation phenotype. As judged by morphology and mucin production a range of differentiation capacities is exhibited by the five cell lines tested under the optimal differentiating culture conditions, with the order from most able to differentiate to least able to differentiate being Caco-2 > or = DLD-1 > or = Widr > HCT 116 > or = HCT 8.

ODC activity and polyamine levels in isolated human colonocytes.

Ornithine decarboxylase (ODC) is the first and often rate-limiting enzyme in polyamine biosynthesis. ODC and polyamines (putrescine, spermidine, spermine, and cadaverine) have an essential role in cell proliferation. In this study, we investigated ODC activity and the polyamine levels of normal human colonocytes isolated from the upper and lower crypt regions. We found no significant differences in ODC activity between upper and lower crypt regions (mean +/- SEM: 105 +/- 60 and 103 +/- 52 pmol CO2/mg protein/hr, respectively). This result was further substantiated by ODC immunoreactive antibody staining technique. Levels of polyamines (putrescine, spermidine, spermine, and cadaverine) were similar in the upper and lower crypt regions (mean +/- SEM; upper/lower: 79 +/- 29/79 +/- 18; 189 +/- 116/ 137 +/- 38; 174 +/- 58/204 +/- 35; and 52 +/- 10/51 +/- 10 nmol/mg protein, respectively). Acetyl-polyamines (acetyl-putrescine, acetyl-spermidine, and acetyl-spermine) levels in human colonocytes showed no significant differences between upper and lower crypt regions (mean +/- SEM; U/L: 368 +/- 109/408 +/- 89, 63 +/- 22/51 +/- 12, and 39 +/- 12/41 +/- 14 nmol/mg protein, respectively). Our results suggest that in isolated normal human colonocytes, ODC activity and polyamine levels are similar in the upper and the lower crypt regions.

Failure of rectal ornithine decarboxylase to identify adenomatous polyp status.

Rectal mucosal ornithine decarboxylase (ODC) activity has been reported to distinguish between patients with and without adenomatous polyps (AP). In the present investigation, ODC activity has been measured in 28 patients with AP and 34 patients without AP. To assess the intraindividual variation in ODC activity, repeat biopsies were performed on 11 patients. In addition, the effect of postbiopsy sample handling was investigated by storage of samples on either dry or wet ice during transport to the laboratory. The mean rectal mucosal ODC activity in patients with AP was 196.0 +/- 195.5, whereas that in AP negative patients was 182.2 +/- 320.5. The rectal mucosal ODC activity in patients with colorectal cancer was 388.2 +/- 581. Repeat samples in individuals were generally within the same range as the original samples. The method of sample transport did not significantly affect the level of ODC measured in a particular biopsy. Because of high variability in rectal mucosal ODC activity within the population, there was wide overlap in ODC values between those patients with and without AP in an unselected general population. Thus, the measurement of flat rectal mucosal ODC activity is not a good predictor of the presence or absence of AP. Additional studies of the factors affecting mucosal ODC activity are necessary before the potential clinical utility of the method can be realized in the general population.

Multiple promoter elements govern expression of the human ornithine decarboxylase gene in colon carcinoma cells.

Overexpression of the ornithine decarboxylase (ODC) gene may be important to the development and maintenance of colonic neoplasms, as well as tumors in general. In this study, we examined the promoter elements governing constitutive expression of the human ODC gene in HCT 116 human colon carcinoma cells and, for comparison, K562 human erythro-leukemia cells. It was determined by functional analysis that the promoter elements responsible reside within the 378 bp immediately upstream from the transcription start site. Within this sequence, there are at least three regions that modulate the efficiency of the ODC promoter cooperatively. Both DNA bandshift and footprint assays demonstrated all three regions to be rich in sites that bind to nuclear proteins isolated from HCT 116 and K562 cells; the protein binding pattern of non-transformed, diploid fibroblasts was found to be much less complex. Several of the protein binding sequences have little or no homology to common regulatory elements. We suggest that the constitutive activity of the ODC gene in HCT 116 colon carcinoma cells, and perhaps transformed cells in general, involves a complex interaction of multiple regulatory sequences and their associated nuclear proteins. Finally, the saturation of the promoter in these transformed cell lines suggests that high levels of protein binding in the ODC promoter may contribute to elevated constitutive expression of this gene.