Randomized Controlled Trial of a Cohesive Eight-Week Evolution Unit That Incorporates Molecular Genetics and Principles of the Next Generation Science Standards.

In response to calls for curricular materials that integrate molecular genetics and evolution and adhere to the K-12 Next Generation Science Standards (NGSS), the Genetic Science Learning Center (GSLC) at the University of Utah has developed and tested the "Evolution: DNA and the Unity of Life" curricular unit for high school biology. The free, 8-week unit illuminates the underlying role of molecular genetics in evolution while providing scaffolded opportunities to engage in making arguments from evidence and analyzing and interpreting data.  We used a randomized controlled trial design to compare student learning when using the new unit with a condition in which teachers used their typical (NGSS-friendly) units with no molecular genetics. Results from nationwide testing with 38 teachers (19 per condition) and their 2269 students revealed that students who used the GSLC curriculum had significantly greater pre/post gain scores in their understanding of evolution than students in the comparison condition; the effect size was moderate. Further, teacher implementation data suggest that students in the treatment condition had more opportunities to engage in argumentation from evidence and have in-class discussions than students in the comparison classes. We consider study implications for the secondary and postsecondary science education community.

Measles Edmonston vaccine strain derivatives have potent oncolytic activity against osteosarcoma.

Osteosarcoma (OS) is the most common primary bone tumor affecting children and young adults, and development of metastatic disease is associated with poor prognosis. The purpose of this study was to evaluate the antitumor efficacy of virotherapy with engineered measles virus (MV) vaccine strains in the treatment of OS. Cell lines derived from pediatric patients with OS (HOS, MG63, 143B, KHOS-312H, U2-OS and SJSA1) were infected with MV expressing green fluorescent protein (MV-GFP) and MV-expressing sodium iodide symporter (MV-NIS) strains. Viral gene expression and cytotoxicity as defined by syncytial formation, cell death and eradication of cell monolayers were demonstrated. Findings were correlated with in vivo efficacy in subcutaneous, orthotopic (tibial bone) and lung metastatic OS xenografts treated with the MV derivative MV-NIS via the intratumoral or intravenous route. Following treatment, we observed decrease in tumor growth of subcutaneous xenografts (P=0.0374) and prolongation of survival in mice with orthotopic (P<0.0001) and pulmonary metastatic OS tumors (P=0.0207). Expression of the NIS transgene in MV-NIS infected tumors allowed for single photon emission computed tomography and positron emission tomography-computed tomography imaging of virus infected tumors in vivo. Our data support the translational potential of MV-based virotherapy approaches in the treatment of recurrent and metastatic OS.

Nottingham trial of faecal occult blood testing for colorectal cancer: a 20-year follow-up.

BACKGROUND: Three large randomised trials have shown that screening for colorectal cancer (CRC) using the faecal occult blood test (FOBt) can reduce the mortality from this disease. The largest of these trials, conducted in Nottingham since 1981, randomised 152,850 individuals between the ages of 45 and 74 years to an intervention arm receiving biennial Haemoccult (FOB) test kit or to a control arm. In 2006, the National Bowel Cancer Screening Programme was launched in England using the FOBt, with the expectation that it will reduce CRC mortality. AIMS: To compare the CRC mortality and incidence in the intervention arm with the control arm after long-term follow-up. METHODS: The 152,850 randomised individuals were followed up through local health records and central flagging (Office for National Statistics). RESULTS: At a median follow-up of 19.5 years there was a 13% reduction in CRC mortality (95% CI 3% to 22%) in the intervention arm despite an uptake at first invitation of approximately 57%. The CRC mortality reduction in those accepting the first screening test, adjusted for the rate of non-compliers, was 18%. There was no significant difference in mortality from causes other than CRC between the intervention and control arms. Despite removing 615 adenomas >10 mm in size from the intervention arm, there was no significant difference in CRC incidence between the two arms. CONCLUSIONS: Although the reduction in CRC mortality was sustained, further follow-up of the screened population has not shown a significant reduction in the CRC incidence. Moreover, despite the removal of many large adenomas there was no reduction in the incidence of invasive cancer which was independent of sex and site of the tumour.

Physiological measurements confirming the diagnosis of cystic fibrosis: the sweat test and measurements of transepithelial potential difference.

Post-natal screening allied with genetic mutation testing has altered our perception of cystic fibrosis (CF) as a clinical entity. Increasingly, infants identified through screening programmes have few or no symptoms or present with atypical forms of the disease. We review how the sweat test has evolved to be the gold standard for confirming the diagnosis of CF and examine its limitations. Other physiological measurements, including nasal potential difference and intestinal current measurement, which might aid in establishing the diagnosis, particularly in patients exhibiting a mild phenotype, are also considered.

Intestinal secretory and absorptive function in Trichinella spiralis mouse model of postinfective gut dysfunction: role of bile acids.

OBJECTIVE: Observations showing that bile acid malabsorption is frequent in irritable bowel syndrome (IBS) suggest that alterations in bile acid-induced secretion and absorption could contribute to IBS-associated diarrhoea. The secretory response to bile acids, fluid transport and bile absorption was examined in intestinal tissues from a Trichinella spiralis mouse model of postinfectious gut dysfunction in vitro. Changes in the protein expression of apical sodium-dependent bile acid transporter (ASBT) were also measured. DESIGN: T. spiralis-infected mice were killed at 18 and 25 days postinfection. Jejunal, ileal, proximal and distal colon segments were exposed to taurodeoxycholic acid (TDCA) or cholic acid. Short circuit current (SCC) increases were determined. Tritiated taurocholic acid (3H-TCA) absorption was determined in everted jejunal and ileal sacs. ASBT protein expression was determined by Western blot analysis and immunohistochemistry. RESULTS: Basal SCC increased in ileum and distal colon at 18 and 25 days postinfection, respectively. Ileal SCC responses to TDCA and cholic acid were enhanced at 18 days postinfection. Distal colon SCC response to TDCA was raised at 18 days postinfection but was significantly reduced by 25 days. Ileal 3H-TCA uptake was significantly reduced at 18 and 25 days postinfection. Surprisingly, increased ASBT expression was observed in infected animals. CONCLUSIONS: In a T. spiralis model of postinfectious gut dysfunction, decreased bile absorption and enhanced secretion in response to bile acids was observed. Decreased absorption was not, however, caused by decreased ASBT as increased expression was observed. If similar events occur postinfection, the combined effects of these disturbances may contribute to some symptoms observed in postinfectious IBS patients.

Absorption of taurocholic acid by the ileum of normal and transgenic DeltaF508 cystic fibrosis mice.

Changes in intestinal transport in cystic fibrosis (CF) include both defective Cl(-) secretion and alterations in absorption. This study focused on the effects of CF on the active re-absorption of bile acids in the ileum of normal and transgenic CF mice. Taurocholic acid absorption was monitored as changes in short-circuit current (SCC) in intact and stripped ileal sheets from normal (Swiss) and transgenic CF (Cftr(tm2Cam)) mice with the DeltaF508 mutation. Taurocholic acid uptake was measured directly in everted ileal sacs and in brush-border membrane vesicles (BBMVs) using radiolabelled bile acid. Taurocholic acid caused a biphasic increase in SCC in both intact and stripped ileal sheets from Swiss mice. The initial phase of the response was associated with active bile acid absorption as it was inhibited by a low mucosal Na(+) concentration, but unaffected by Cl(-)-free conditions, serosal furosemide or mucosal diphenylamine-2-carboxylic acid (DPC). The first phase was concentration-dependent and was reduced in the presence of other actively transported bile acids. Intact ileal sheets from wild-type Cftr(tm2Cam) mice also exhibited a biphasic SCC response to taurocholic acid, but in CF tissues the initial phase was reduced and the second phase was absent. Taurocholic acid was actively taken up by everted ileal sacs from Swiss mice. This process was inhibited by a low mucosal Na(+) concentration or the presence of other actively transported bile acids. A similar taurocholic acid uptake was observed in ileal sacs from wild-type mice, but in those from CF mice transport of the bile acid was significantly reduced. However, taurocholic acid uptake was similar in BBMVs from wildtype and CF ilea. Active absorption of taurocholic acid occurs in mouse ileum and this process is reduced in transgenic mouse models of CF with the DeltaF508 mutation. However, this difference cannot be detected in an isolated preparation of brush-border membranes.

Small intestinal glucose absorption in cystic fibrosis: a study in human and transgenic DeltaF508 cystic fibrosis mouse tissues.

Intestinal transport is disturbed in cystic fibrosis (CF), with both defective Cl- secretion and changes in absorption being reported. We have examined the effects of the disease on Na(+)-dependent glucose absorption by the small intestine. Active glucose absorption was monitored as changes in short-circuit current (SCC) in intact and stripped intestinal sheets from normal (Swiss) and transgenic CF (Cftr(tm1Eur) and Cftr(tm2Cam)) mice with the DeltaF508 mutation, and in jejunal biopsies from children with CF and normal controls. Na(+)-dependent glucose uptake at the luminal membrane was measured in brush-border membrane vesicles (BBMVs). Intact and stripped sheets of jejunum and midintestine from Swiss mice exhibited a concentration-dependent increase in SCC with glucose. Apparent Km values were similar in the two preparations, but the apparent Vmax was greater in stripped sheets. This difference was not due to a loss of neural activity in stripped sheets as tetrodotoxin did not influence the glucose-induced SCC in intact sheets. Similar results were observed in stripped sheets of jejunum and mid-intestine from wild-type Cftr(tm1Eur) mice, but in tissues from CF mice the apparent Vmax value was reduced significantly. A lower Vmax was also obtained in intact sheets of mid-intestine from CF (Cftr(tm2Cam)) mice. Jejunal biopsies from CF patients however, exhibited an enhanced glucose-dependent rise in SCC. Na(+)-dependent uptake by BBMVs from CF (Cftr(tm1Eur)) mice was not reduced compared with wild-type and Swiss BBMVs. It was concluded that, in contrast to human intestine, intestinal glucose absorption was reduced in transgenic mouse models of CF with the DeltaF508 mutation, but that this could not be detected in an isolated preparation of brush-border membranes. Transgenic mouse models of CF may not accurately reflect all aspects of intestinal dysfunction in the human disease.

Colorectal cancer, screening and survival: the influence of socio-economic deprivation.

OBJECTIVES: To determine the extent to which socio-economic deprivation explains colorectal cancer prevalence, subject participation in screening, and postoperative survival and life expectancy. METHODS: Regression analyses of clinical data from a large randomized controlled trial, augmented by geographical-based indices of deprivation. RESULTS: Deprivation appears to exert no significant impact on colorectal cancer prevalence but is a major factor explaining subject participation in screening. Cancer detection at later stages reduces life expectancy at time of treatment. Females from more-deprived areas have poorer post-treatment life expectancies and survival prospects, independently of their screening behaviour. CONCLUSIONS: Screening increases the chances of having a cancer treated at an earlier stage, and treatment at an earlier stage is associated with longer subsequent life expectancy. However, those from more-deprived areas are less likely to accept an invitation to be screened.

Effect of faecal occult blood screening on mortality from colorectal cancer: results from a randomised controlled trial.

BACKGROUND: Three large randomised trials have shown that screening for colorectal cancer using faecal occult blood (FOB) tests can reduce the mortality from this disease. Two national pilot studies have recently been launched in the UK to investigate the feasibility of population screening for colorectal cancer in the National Health Service. The largest of the randomised trials was conducted in Nottingham and randomised 152 850 individuals between the ages of 45 and 74 years to receive biennial Haemoccult (FOB) test kit (intervention group) or to a control group. AIMS: We have compared the mortality in the intervention group compared with the control group. METHODS: The 152 850 randomised individuals were followed up through local health records and central flagging (Office for National Statistics) over a median follow up period of 11 years. RESULTS: At a median follow up of 11 years there was a 13% reduction in colorectal cancer mortality (95% confidence interval 3-22%) in the intervention group despite an uptake at first invitation of only approximately 50%. The mortality reduction for those accepting screening was 27%. The reduction in mortality was independent of sex and site of tumour. There was no significant difference in mortality from causes other than colorectal cancer between the intervention and control groups. CONCLUSIONS: Although the reduction in colorectal cancer mortality was sustained, further follow up of this population is required to determine whether a significant reduction in the incidence of colorectal cancer will be achieved.

Psychiatric morbidity and screening for colorectal cancer.

BACKGROUND: Several studies have shown that faecal occult blood (FOB) screening reduces mortality from colorectal cancer. However, concern has been expressed that health screening may have adverse psychological effects, particularly for the group returning false positive tests. OBJECTIVES: To evaluate any adverse psychological effects associated with faecal occult blood screening. SETTING: Randomised controlled trial of faecal occult blood screening for colorectal cancer. METHODS: Psychiatric morbidity was measured, using the general health questionnaire (GHQ) before and 3 months after the offer of screening for colorectal cancer with FOB testing. Scores were related to acceptance of the screening test. A smaller cohort, who had returned positive FOB tests, had anxiety levels measured, using the Spielberger anxiety inventory (SAI), at different times during screening, investigation, and follow up. RESULTS: A GHQ was sent to 2184 subjects before the offer of screening, and 1541 (70.6%) were returned. Of the 1693 subjects offered the GHQ 3 months after the offer of screening, 1303 (77%) returned it. A GHQ score of 5 or more, indicating possible psychiatric morbidity, was present in 454 subjects (29.5%) before screening and in 386 (29.6%) subjects 3 months after screening (NS). Of the 454 subjects who scored 5 or more, 241 (53.1%) accepted screening and 213 (46.9%) refused. A total of 1081 subjects scored less than 5, and of these 521 (48.2%) accepted screening and 560 (51.8%) refused (NS). Anxiety scores were measured in 100 test positive patients and were highest after notification of a positive test and before investigation by colonoscopy. In patients with false positive results, scores fell the day after colonoscopy and remained low 1 month later. CONCLUSIONS: The receipt of a screening test does not cause sustained anxiety and the existence of psychiatric morbidity is not a factor affecting a person's decision to accept or refuse a screening test for colorectal cancer.

High prevalence of undetected ulcerative colitis: data from the Nottingham fecal occult blood screening trial.

OBJECTIVES: Inflammatory bowel disease (IBD) is usually diagnosed as a result of symptoms but occasionally is found during investigation for other conditions. An earlier report from Nottingham had found a high prevalence of previously undetected "asymptomatic" IBD detected as a result of colorectal cancer screening, and the aim of this study was to reassess the prevalence, symptoms, and outcome in these patients. METHODS: We investigated subjects found to be fecal occult blood (FOB) positive in a randomized trial of FOB screening for colorectal cancer. All FOB-positive subjects were investigated by colonoscopy or flexible sigmoidoscopy and barium enema. Subjects with IBD were referred back to their general practitioner for any further investigation and treatment. RESULTS: Seventy-five thousand two hundred fifty-three subjects (aged 45-74) were sent FOB tests and 44,838 (60%) completed a series of tests on one or more occasions. Of 133,000 test series, 1.5% were positive. During investigation 53 cases of previously undetected IBD (52 of ulcerative colitis) were found; 52% (27/52) had proctosigmoiditis only, whereas 25% (13/52) had pancolitis. Only 17% (9/52) were completely asymptomatic, with a half or more reporting some rectal bleeding (54%) or diarrhea (50%). The overall prevalence of undetected ulcerative colitis was 69/10(5) (95% CI = 50-88/10(5)) in people offered screening and 116/10(5) (95% CI = 85-147/10(5)) in people accepting screening and was higher in men. Of 32 subjects followed up 2-12 yr after diagnosis, 91% (29) continued to have few or no symptoms, with only 12 currently receiving any treatment for their colitis. CONCLUSIONS: In comparison with detected disease, undetected ulcerative colitis is relatively common but does usually cause some symptoms. It generally appears to follow a benign course, but a significant proportion have extensive colitis and may therefore be at an increased risk of colorectal cancer.

Ursodeoxycholic acid action on the transport function of the small intestine in normal and cystic fibrosis mice.

Ursodeoxycholic acid possesses choleretic and cytoprotective properties and in cystic fibrosis (CF) it is used to treat the hepatobiliary symptoms of the disease. This study investigated the effects of this bile acid on the transport function of the small intestine in normal and CF mice. The effects of ursodeoxycholic acid were monitored as changes in short-circuit current (SCC) in stripped sheets of small intestine from normal (Swiss MF1) and transgenic CF (Cftr(tm2Cam)) mice. In ileal sheets from Swiss MF1 mice, mucosal ursodeoxycholic acid caused a biphasic increase in SCC. The first phase was reduced by lowering the mucosal Na+ concentration, while the second phase was inhibited by (Cl-)-free conditions, serosal furosemide or mucosal diphenylamine-2-carboxylic acid (DPC), suggesting an initial Na+-dependent bile acid absorption followed by a stimulation of electrogenic Cl- secretion. Serosal application of ursodeoxycholic acid to the ileum and mucosal or serosal application to the mid-intestine and jejunum elicited a secretory response only. Secretion was Ca2+-dependent, but did not involve neural mechanisms. Mucosal mast cells, histamine and serotonin (5-HT) were implicated in the secretory response. Responses in tissues from transgenic wild-type mice were similar to those obtained with Swiss MF1 mice, but the secretory response to mucosal or serosal application of the bile acid was impaired in CF tissues. In ilea from CF mice the initial absorptive phase of the response to mucosal ursodeoxycholic acid was still observed. It is concluded that ursodeoxycholic acid induces secretion throughout the murine small intestine by a mechanism that involves degranulation of mucosal mast cells. In the ileum Na+-dependent absorption can also be detected. The secretory response is defective in CF intestine, but the absorptive effect is still present.

Randomized double-blind phase II survival study comparing immunization with the anti-idiotypic monoclonal antibody 105AD7 against placebo in advanced colorectal cancer.

The cancer vaccine 105AD7 is an anti-idiotypic monoclonal antibody that mimics the tumour-associated antigen 791T/gp72 (CD55, Decay Accelerating Factor) on colorectal cancer cells. Phase I studies in patients with advanced disease confirmed that 105AD7 is non-toxic, and that T cell responses could be generated. A prospective, randomized, double-blind, placebo-controlled survival study in patients with advanced colorectal cancer was performed. 162 patients were enrolled between April 1994 and October 1996. Patients attended at trial entry, and at 6 and 12 weeks, where they received 105AD7 or placebo. Study groups were comparable in terms of patient demographics, and time from diagnosis of advanced colorectal cancer (277.1 v 278.6 days). Baseline disease was similar, with 50% of patients having malignancy in at least 2 anatomic sites. Compliance with treatment was poor, with only 50% of patients receiving 3 planned vaccinations. Median survival from randomization date was 124 and 184 days in 105AD7 and placebo arms respectively (P = 0.38), and 456 and 486 days from the date of diagnosis of advanced disease (P = 0.82). 105AD7 vaccination does not prolong survival in patients with advanced colorectal cancer. The reasons for lack of efficacy are unclear, but may reflect the high tumour burden in the patient population, and poor compliance with immunization. Further vaccine studies should concentrate on patients with minimal residual disease.

Taurocholic acid-induced secretion in normal and cystic fibrosis mouse ileum.

Bile acids cause secretion throughout the intestinal tract and this process contributes to maintaining the fluidity of intestinal contents. In cystic fibrosis (CF) defective intestinal secretion can lead to excessive dehydration of the luminal contents and the development of clinical symptoms. This study was designed to investigate bile acid-induced secretion in mouse ileum and to determine whether this process was defective in CF. Taurocholic acid-induced secretion was monitored as a rise in short-circuit current (SCC) in ileal sheets from normal (Swiss MF1) and transgenic CF mice. Taurocholic acid increased the SCC in both intact and stripped ileal sheets from Swiss MF1 mice. This effect was due to a stimulation of electrogenic Cl- secretion as it was inhibited by Cl(-)-free conditions, serosal furosemide (frusemide), mucosal diphenylamine-2-carboxylic acid (DPC) and increased serosal K+ concentration, without being affected by reduced mucosal Na+ concentration. Taurocholic acid-induced secretion was inhibited by tetrodotoxin, indicating the involvement of a neural pathway, but this did not include capsaicin-sensitive afferent neurons or muscarinic cholinoreceptors. Mucosal mast cells also contributed to the response. Responses in tissues from transgenic wild-type mice were similar to those obtained with Swiss MF1 animals, but ilea from CF mice exhibited a lower basal SCC with significantly reduced secretory responses to acetylcholine and taurocholic acid. We concluded that taurocholic acid induces ileal secretion by a mechanism that entails activation of enteric nerves and degranulation of mucosal mast cells. Impaired bile acid-induced secretion in CF may contribute to luminal dehydration.

Acetylcholine induces cytosolic Ca2+ mobilization in isolated distal colonic crypts from normal and cystic fibrosis mice.

In intestinal biopsies from cystic fibrosis (CF) patients acetylcholine fails to elicit a chloride secretion response, and this observation can be explained by a defect in the Ca2+ signalling pathway in CF secretory cells. We tested the hypothesis that in CF intestine, the generation of an intracellular Ca2+ signal upon cholinergic stimulation is absent. A transgenic CF mouse model was used. Electrical measurements on intact jejunum and unstripped colon were performed in Ussing chambers. Intact distal colonic crypts were isolated, and the intracellular Ca2+ concentration was monitored using the Ca2+-sensitive dye fura-2. Acetylcholine increased the short-circuit current generated by wild-type jejunum and colon, but failed to induce a response in CF tissues. Acetylcholine caused a transient elevation in the intracellular Ca2+ concentration in colonic crypts from both wild-type and CF mice; the amplitude and timing of the response in CF crypts was indistinguishable from that in wild-type crypts. The response to acetylcholine was also observed in the absence of extracellular calcium, indicating intracellular stores as the source from which the cytosolic Ca2+ concentration increased. We conclude that the absence of a cholinergically-induced secretory response in CF intestine is not due to a defect in the generation of a Ca2+ signal in intestinal cells upon cholinergic stimulation.

The electroanalytical detection and determination of copper in heavily passivating media: ultrasonically enhanced solvent extraction by N-benzoyl-N-phenyl-hydroxylamine in ethyl acetate coupled with electrochemical detection by sono-square wave stripping voltammetry analysis.

N-benzoyl-N-phenyl-hydroxylamine dissolved in ethyl acetate was employed as a ligand for the solvent extraction of copper. Ultrasonic emulsification was shown to be effective both in the extraction of copper from an aqueous phase into ethyl acetate and its recovery or "back extraction" into a fresh clean aqueous solution. Experimental determination of thermodynamic parameters governing the extraction process via UV/visible spectroscopy is reported. This permitted theoretical predictions for the amount of copper transferred into the final aqueous solution to be fitted to experimental data. Quantitative analysis of copper removed via double sono-extraction from an aqueous medium hostile to voltammetric analysis proceeded via sono-square wave anodic stripping voltammetry analysis (sono-SWASV). This resulted in very high sensitivity in the relatively clean medium. The technique was then applied to the analysis of copper in the soft drink 'Ribena Light'. In the absence of sample preparation by solvent extraction sono-SWASV yields a measurable peak current for copper. However it is irreproducible and erratic due to passivating effects, possibly attributed to the sugars, natural flavourings and colourings present. Following sono-solvent extraction, the overall copper concentration could be obtained with a detection limit of 2 microg L(-1). Biphasic sono-extraction synergistically coupled with the recognized technique sono-SWASV presents an attractive technique for copper analysis in electrode passivating media. The technique necessarily removes contaminants present in the test solution since these will prefer to remain in the initial aqueous phase, or will transfer to the organic phase but are unlikely to be doubly transferred into the 'clean' final aqueous phase.

Faecal occult blood screening for colorectal cancer at Nottingham: details of the verification process.

Cause specific mortality statistics derived from death certificates are highly dependent upon the accuracy of certification by the attending physician. In the Nottingham colorectal cancer screening trial, there were 12,624 deaths among the screening group and 12,515 among the control group during the period under consideration. There was no significant difference in all cause mortality rate (excluding deaths due to colorectal cancer) between the two study groups (rate ratio = 1.01, 95% confidence interval = 0.99 to 1.03). Disease specific mortality rates did not differ significantly between the two groups either. Overall, the agreement between verified and certified cause of death was 86%. Using the certified cause of death would have resulted in an underestimation bias of 6.27% for colorectal cancer deaths.

Effect of loperamide on Na+/D-glucose cotransporter activity in mouse small intestine.

The mu-opioid agonist loperamide is an antidiarrhoeal drug which inhibits intestinal motility and secretion. Its anti-absorptive effects are less well investigated, but may be mediated through calmodulin. We have investigated further the effect of loperamide on the intestinal Na+-dependent D-glucose transporter (SGLT1). Brush-border membrane vesicles were prepared from mouse small intestine, and uptake of [3H]glucose was measured. Na+-dependent glucose uptake displayed the typical overshoot at 34 s; the peak value was 1.6 nmol mg(-1). The overshoot disappeared in the presence of phlorizin or when Na+ was replaced by K+. Extravesicular loperamide dose-dependently inhibited SGLT1 activity with an IC50 value of 450 micromol L(-1). Loperamide displayed a mixed inhibition type: the apparent Vmax decreased from 0.9 to 0.5 nmol mg(-1)/15 s, the apparent Km increased from 0.23 to 1.13 mmol L(-1) glucose. Na+ kinetics were more complex, but loperamide inhibited net glucose uptake by 90% at 100 mmol L(-1) Na+. Glucose uptake was unchanged by agents affecting calmodulin activity. Loperamide inhibited intestinal Na+, K+-ATPase activity, whilst sucrase activity was unaffected. SGLT1 activity was inhibited by loperamide, but this effect was not mediated through calmodulin. As this action is only evident at high concentrations of loperamide a nonspecific mechanism may be involved.

A prospective multicenter evaluation of new fecal occult blood tests in patients undergoing colonoscopy.

OBJECTIVE: Guaiac-based fecal occult blood (FOB) tests, in particular, Hemoccult II (HO), are commonly used to detect colorectal neoplasia. Because the sensitivity and specificity of these tests are critical to cost-effective screening programs, we aimed to investigate the improved performance characteristics of new FOB tests for known colonic lesions. METHODS: Nine centers worldwide performed FOB testing with guaiac-based tests (Hemoccult II [HO] and Hemoccult II SENSA [SENSA]) and immunochemical tests (HemeSelect [HS] and FlexSure OBT [FS]) on 554 patients referred for colonoscopy for predetermined indications. A combination testing strategy consisting of SENSA followed by HS or FS (which was considered positive only when both tests were positive) was also evaluated. Results of FOB tests were compared to findings on colonoscopy. RESULTS: Cancers were identified in 2.9% of subjects, whereas adenomas > or =10 mm were found in 39 patients. Small adenomas, colitis, and other lesions were identified in 141 patients. The positivity rate of HO for adenomas > or =10 mm was less than for SENSA (20.5% vs 35.9%, p < 0.05), whereas the positivity rate of HO, SENSA, FS, HS, or the combination tests for cancers was not statistically different. The overall positivity rates were significantly greater for FS (15.9%, p = 0.0002) and significantly lower using the combination tests (SENSA/FS 6.0%, p = 0.01; SENSA/HS 6.2%, p = 0.02) compared to HO (9.4%). In this study population, the relative specificity (i.e., true-negative tests/true-negatives + false-positives in patients without adenomas > or =10 mm or cancers) of HO (93.9%; 95% CI, 91.7-96.1) was similar to that of SENSA (92.8%; 95% CI, 90.4-95.2) and HS (90.1%; 95% CI, 87.4-92.8), and greater than FS (88.0%; 95% CI, 85.1-90.9, p < 0.001). When considering adenomas > or =10 mm, cancers alone or cancers and adenomas combined, the combination test using SENSA/FS was associated with significantly fewer false-positive tests than any of the individual tests. CONCLUSIONS: Compared to single tests, the combination test with the highly sensitive SENSA and an immunochemical test had slightly reduced sensitivity but significantly fewer false-positive tests than any single test. These data raise the possibility that a combination test (i.e., highly sensitive guaiac plus immunochemical) could reduce the costs of screening for colon cancer, and suggest that further study of combination test strategies is warranted.

Faecal calprotectin levels in a high risk population for colorectal neoplasia.

BACKGROUND: Faecal concentrations of the protein calprotectin have been found to be elevated in patients with colorectal neoplasia, suggesting that it might be used as a screening tool for colorectal cancer as well as adenomas. AIMS: To measure the sensitivity and specificity of faecal calprotectin for the detection of adenomas in high risk individuals undergoing colonoscopy. Also, to investigate between and within stool variability of calprotectin concentrations. SUBJECTS: A total of 814 patients planned for colonoscopy were included for the following indications: positive faecal occult blood test, 25; neoplasia surveillance, 605; newly detected polyp, 130; and family risk, 54. METHODS: Two faecal samples from each of two stools were analysed using the PhiCal ELISA test device (Nycomed Pharma AS). RESULTS: Adenoma patients had significantly higher calprotectin levels than normal subjects (median 9.1 (95% confidence interval 7.5-10.1) v 6.6 (5.6-7.4)mg/l). There was no significant decrease in calprotectin levels after polypectomy. Levels in cancer patients were significantly higher than those in all other subgroups (median 17.6 mg/l (11.5-31.0)). With a cut off limit of 10 mg/l, the sensitivity for cancer was 74% and for adenoma 43%. Corresponding specificity values were 64% for no cancer and 67% for no neoplasia (cancer+adenoma). Specificity varied from 71% for one stool sample to 63% for four samples. Stool variability was small, suggesting that two spots from one stool were as discriminative as two spots from each of two stools. CONCLUSIONS: The sensitivity and specificity of faecal calprotectin levels as a marker for colorectal adenoma and carcinoma justifies its use in high risk groups, but specificity is too low for screening of average risk persons. Lack of a decrease in levels after polypectomy may be due to a more widespread leucocyte migration into the intestinal lumen than that at the polyp site, and needs further investigation.