Definition and taxonomy of interval colorectal cancers: a proposal for standardising nomenclature.

OBJECTIVE: Interval colorectal cancers (interval CRCs), that is, cancers occurring after a negative screening test or examination, are an important indicator of the quality and effectiveness of CRC screening and surveillance. In order to compare incidence rates of interval CRCs across screening programmes, a standardised definition is required. Our goal was to develop an internationally applicable definition and taxonomy for reporting on interval CRCs. DESIGN: Using a modified Delphi process to achieve consensus, the Expert Working Group on interval CRC of the Colorectal Cancer Screening Committee of the World Endoscopy Organization developed a nomenclature for defining and characterising interval CRCs. RESULTS: We define an interval CRC as a "colorectal cancer diagnosed after a screening or surveillance exam in which no cancer is detected, and before the date of the next recommended exam". Guidelines and principles for describing and reporting on interval CRCs are provided, and clinical scenarios to demonstrate the practical application of the nomenclature are presented. CONCLUSIONS: The Working Group on interval CRC of the World Endoscopy Organization endorses adoption of this standardised nomenclature. A standardised nomenclature will facilitate benchmarking and comparison of interval CRC rates across programmes and regions.

An updated Asia Pacific Consensus Recommendations on colorectal cancer screening.

OBJECTIVE: Since the publication of the first Asia Pacific Consensus on Colorectal Cancer (CRC) in 2008, there are substantial advancements in the science and experience of implementing CRC screening. The Asia Pacific Working Group aimed to provide an updated set of consensus recommendations. DESIGN: Members from 14 Asian regions gathered to seek consensus using other national and international guidelines, and recent relevant literature published from 2008 to 2013. A modified Delphi process was adopted to develop the statements. RESULTS: Age range for CRC screening is defined as 50-75 years. Advancing age, male, family history of CRC, smoking and obesity are confirmed risk factors for CRC and advanced neoplasia. A risk-stratified scoring system is recommended for selecting high-risk patients for colonoscopy. Quantitative faecal immunochemical test (FIT) instead of guaiac-based faecal occult blood test (gFOBT) is preferred for average-risk subjects. Ancillary methods in colonoscopy, with the exception of chromoendoscopy, have not proven to be superior to high-definition white light endoscopy in identifying adenoma. Quality of colonoscopy should be upheld and quality assurance programme should be in place to audit every aspects of CRC screening. Serrated adenoma is recognised as a risk for interval cancer. There is no consensus on the recruitment of trained endoscopy nurses for CRC screening. CONCLUSIONS: Based on recent data on CRC screening, an updated list of recommendations on CRC screening is prepared. These consensus statements will further enhance the implementation of CRC screening in the Asia Pacific region.

Body mass index in early adulthood and colorectal cancer risk for carriers and non-carriers of germline mutations in DNA mismatch repair genes.

BACKGROUND: Carriers of germline mutations in DNA mismatch repair (MMR) genes have a high risk of colorectal cancer (CRC), but the modifiers of this risk are not well established. We estimated an association between body mass index (BMI) in early adulthood and subsequent risk of CRC for carriers and, as a comparison, estimated the association for non-carriers. METHODS: A weighted Cox regression was used to analyse height and weight at 20 years reported by 1324 carriers of MMR gene mutations (500 MLH1, 648 MSH2, 117 MSH6 and 59 PMS2) and 1219 non-carriers from the Colon Cancer Family Registry. RESULTS: During 122,304 person-years of observation, we observed diagnoses of CRC for 659 carriers (50%) and 36 non-carriers (3%). For carriers, the risk of CRC increased by 30% for each 5 kg m(-2) increment in BMI in early adulthood (hazard ratio, HR: 1.30; 95% confidence interval, CI: 1.08-1.58; P=0.01), and increased by 64% for non-carriers (HR: 1.64; 95% CI: 1.02-2.64; P=0.04) after adjusting for sex, country, cigarette smoking and alcohol drinking (and the MMR gene that was mutated in carriers). The difference in HRs for carriers and non-carriers was not statistically significant (P=0.50). For MLH1 and PMS2 (MutLα heterodimer) mutation carriers combined, the corresponding increase was 36% (HR: 1.36; 95% CI: 1.05-1.76; P=0.02). For MSH2 and MSH6 (MutSα heterodimer) mutation carriers combined, the HR was 1.26 (95% CI: 0.96-1.65; P=0.09). There was no significant difference between the HRs for MutLα and MutSα heterodimer carriers (P=0.56). CONCLUSION: Body mass index in early adulthood is positively associated with risk of CRC for MMR gene mutation carriers and non-carriers.

Assessment of the allelopathic potential of Juniperus ashei on germination and growth of Bouteloua curtipendula.

Potential allelopathic compounds of Juniperus ashei Buchh. (Ashe juniper) and their effect on a native grass were determined in laboratory and field studies. Solid-phase microextraction and gas chromatography/mass spectrometry were used to determine if monoterpenes found in the essential oils of J. ashei are released in leaf and litter leachate, as well as volatilized from leaf tissue. Camphor, bornyl acetate, and limonene were found in leaf and fresh litter leachates; however, degraded litter did not contain any of these compounds. Camphor was the most common potentially allelopathic compound found in J. ashei leaf and litter leachate and in volatiles from leaf tissue. The effects of leaf and litter tissue on the germination of Bouteloua curtipendula (Michx.) Torr. (side-oats grama) was tested by using the "sandwich agar method". The highest germination of B. curtipendula (29.6%) occurred in the control, which was significantly higher than fresh litter (13.2%) and degraded litter (16.2%). The lowest germination (6.2%) occurred with J. ashei leaves. In the field experiment, aboveground dry mass of B. curtipendula was evaluated in relation to position within the canopy and intercanopy of J. ashei adult trees when light and water were held constant across locations. Aboveground dry mass of B. curtipendula was significantly greater in the intercanopies of J. ashei (163.7 g m(2)) compared to the dry mass in the understory (44.8 g m(2)) and dripline (44.5 g m(2)), suggesting some negative influence by J. ashei. Chemical analyses indicate that monoterpenes are released through leaching and volatilization from J. ashei, and germination and field studies suggest that these compounds inhibit B. curtipendula.

Asia Pacific consensus recommendations for colorectal cancer screening.

Colorectal cancer (CRC) is rapidly increasing in Asia, but screening guidelines are lacking. Through reviewing the literature and regional data, and using the modified Delphi process, the Asia Pacific Working Group on Colorectal Cancer and international experts launch consensus recommendations aiming to improve the awareness of healthcare providers of the changing epidemiology and screening tests available. The incidence, anatomical distribution and mortality of CRC among Asian populations are not different compared with Western countries. There is a trend of proximal migration of colonic polyps. Flat or depressed lesions are not uncommon. Screening for CRC should be started at the age of 50 years. Male gender, smoking, obesity and family history are risk factors for colorectal neoplasia. Faecal occult blood test (FOBT, guaiac-based and immunochemical tests), flexible sigmoidoscopy and colonoscopy are recommended for CRC screening. Double-contrast barium enema and CT colonography are not preferred. In resource-limited countries, FOBT is the first choice for CRC screening. Polyps 5-9 mm in diameter should be removed endoscopically and, following a negative colonoscopy, a repeat examination should be performed in 10 years. Screening for CRC should be a national health priority in most Asian countries. Studies on barriers to CRC screening, education for the public and engagement of primary care physicians should be undertaken. There is no consensus on whether nurses should be trained to perform endoscopic procedures for screening of colorectal neoplasia.

An advance notification letter increases participation in colorectal cancer screening.

OBJECTIVES: To determine the impact of novel invitation strategies on population participation in faecal immunochemical test (FIT)-based colorectal cancer (CRC) screening. SETTING: A community screening programme in Adelaide, South Australia. METHODS: In total, 2400 people aged 50-74 years were randomly allocated to one of four CRC screening invitation strategies: (a) CONTROL: standard invitation-to-screen letter explaining risk of CRC and the concept, value and method of screening; (b) Risk: invitation with additional messages related to CRC risk; (c) Advocacy: invitation with additional messages related to advocacy for screening from previous screening programme participants and (d) Advance Notification: first, a letter introducing CONTROL letter messages followed by the standard invitation-to-screen. Invitations included an FIT kit. Programme participation rates were determined for each strategy relative to control. Associations between participation and sociodemographic variables were explored. RESULTS: At 12 weeks after invitation, participation was: CONTROL: 237/600 (39.5%); Risk: 242/600 (40.3%); Advocacy: 216/600 (36.0%) and Advance Notification: 290/600 (48.3%). Participation was significantly greater than CONTROL only in the Advance Notification group (Relative risk [RR] 1.23, 95% confidence interval [CI] 1.06-1.43). This effect was apparent as early as two weeks from date of offer; Advance Notification: 151/600 (25.2%) versus CONTROL: 109/600 (18.2%, RR 1.38, 95% CI 1.11-1.73). CONCLUSIONS: Advance notification significantly increased screening participation. The effect may be due to a population shift in readiness to undertake screening, and is consistent with the Transtheoretical Model of behaviour change. Risk or lay advocacy strategies did not improve screening participation. Organized screening programmes should consider using advance notification letters to improve programme participation.

Increasing selenium concentration in milk: effects of amount of selenium from yeast and cereal grain supplements.

Two experiments were conducted to establish responses in milk Se concentrations in grazing dairy cows to different amounts of dietary Se yeast, and to determine the effects of the Se concentration of the basal diet. The hypothesis tested was that the response in milk, blood, and tissue Se concentrations to supplemental Se would not be affected by whether the Se was from the basal diet or from Se yeast. In addition, by conducting a similar experiment in either early (spring; experiment 1) or late (autumn; experiment 2) lactation, we hypothesized that different Se input-output relationships would result. Both 6-wk experiments involved 60 multiparous Holstein-Friesian cows, all of which had calved in spring. They were allocated to 1 of 10 dietary Se treatments that included 2 types of crushed triticale grain (low Se, approximately 165 microg of Se/kg of DM; or high Se, approximately 580 microg/kg of DM) fed at 4 kg of DM/d, and 1 kg of DM/d of pellets formulated to carry 5 quantities of Se yeast (0, 4, 8, 12, or 16 mg of Se). Daily total Se intakes ranged from <2 to >18 mg/cow in both experiments. Milk Se concentrations plateaued after 15 and 7 d of supplementation in experiments 1 and 2, respectively, and then remained at plateau concentrations. Average milk Se concentrations for the plateau period increased as the amount of Se yeast increased, and low- and high-Se grain treatments were different at all quantities of Se yeast, although there was a tendency for this difference to diminish at the greatest concentrations of yeast. There were significant positive, linear relationships between Se intake and the concentrations of Se in milk, which were not affected by the source of Se, and the relationships were similar for both experiments. Therefore, the output of Se in milk in experiment 1 was greater than that in experiment 2 because the milk yield of the cows in early lactation was greater. The estimated proportions of Se partitioned to destinations other than milk and feces increased with the amount of Se in the diet and were greater in experiment 2 than in experiment 1, a result that was supported by Se concentrations in whole blood and plasma and in semitendinosus muscle tissue. If high-Se products are to be produced for human nutrition, it is important to be able to develop feeding systems that produce milk with consistent and predictable Se concentrations so that products can consistently meet specifications. The results indicate that this objective is achievable.

Screening for colorectal cancer by faecal occult blood test: why people choose to refuse.

To better understand the personal barriers that limit participation in faecal occult blood test (FOBT) screening for colorectal cancer, non-participants from a recent screening initiative were sent detailed questionnaires, defining their reasons for not participating, as well as how to make screening more attractive. The important barrier was procrastination. The type of FOBT kit offered influenced the reasons for not participating. Convenient FOBT and greater general practitioner involvement may be important for optimizing community acceptance of FOBT-based screening.

Induction of caspase-3 protease activity and apoptosis by butyrate and trichostatin A (inhibitors of histone deacetylase): dependence on protein synthesis and synergy with a mitochondrial/cytochrome c-dependent pathway.

The induction of apoptosis of tumor cells by the colonic fermentation product butyrate is thought to be an important mechanism in protection against colorectal cancer. Because a major action of butyrate is to inhibit histone deacetylase (leading to chromatin relaxation and altered gene expression), butyrate may induce apoptosis by derepression of specific cell death genes. Here we show that butyrate and trichostatin A (a more selective inhibitor of histone deacetylase) induce the same program of apoptosis in Jurkat lymphoid and LIM 1215 colorectal cancer cell lines that is strictly dependent on new protein synthesis (within 10 h) and that leads to the conversion of the proenzyme form of caspase-3 to the catalytically active effector protease (within 16 h) and apoptotic death (within 24 h). Cells primed with a low concentration of butyrate that itself did not induce activation of caspase-3 or apoptosis were, nevertheless, rendered highly susceptible to induction of apoptosis by staurosporine (an agent that has recently been shown to act by causing mitochondrial release of cytochrome c). Synergy between butyrate and staurosporine was due to the presence of a factor in the cytosol of butyrate-primed cells which enhanced over 7-fold the activation of caspase-3 induced by the addition of cytochrome c and dATP to isolated cytosol. We propose that changes at the level of chromatin structure, induced by a physiological substance butyrate, lead to the expression of a protein that facilitates the pathway by which mitochondria activate caspase-3 and trigger apoptotic death of lymphoid and colorectal cancer cells.

Influence of duodenal secretions and its components on release and activities of human brush-border enzymes.

The in vitro effects of human duodenal secretions and various combinations of its components on activity and release of enzymes from the human brush border were examined. Sucrase retained activity for 90 min in duodenal secretions, and maltase was almost as stable; lactase lost activity rapidly and alkaline phosphatase was of intermediate stability. Inactivation of lactase could only be partly (50%) attributed to luminal proteases, bile salts and phospholipids played no role. Rate of release of an enzyme from the brush border bore no relationship to its rate of inactivation. When individual proteases were studied, elastase was the most potent for releasing disaccharidases from the brush border; trypsin was ineffective alone but augmented the effect of elastase. Sucrase and maltase were activated by proteolytic release, but activation was abolished by simultaneous exposure of brush borders to bile salts. Lactase was released and rapidly inactivated by proteinases, while alkaline phosphatase appeared to be inactivated without significant release. These results show that there are significant interactions between luminal factors which have been inapparent when studying them in isolation. Loss of functionally useful enzyme does not follow release of sucrase or maltase from the brush border into the lumen but does follow release of lactase. Study of the susceptibility of lactase to inactivation by luminal factors in the various forms of lactose intolerance is warranted.

Labelling of intestinal brush border membrane proteins in vivo using diazotised[125I]iodosulfanilic acid.

Membrane proteins of the intestinal brush border were labelled in vivo by intraluminal injection of diazotised [125I]iodosulfanilic acid, a highly polar molecule. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of brush border membranes labelled in this manner showed 20 protein bands, 11 of which contained significant radioactivity. The most heavily labelled proteins had molecular weights greater than 150000, indicating that they were the most exposed to the intestinal lumen. Little radioactivity was detected in proteins with molecular weights of less than 94000. The majority of these smaller proteins were likely to have been brush border core proteins. The evidence that diazotised [125I]iodosulfanilic acid bound primarily to brush border membrane proteins when administered in this way, was: (a) the specific activity of brush border proteins was up to 3-fold greater than that of total cell particulate proteins (pelleted by 27000 x g from mucosal homogenates); (b) principal peaks in the gel radioactivity profile of total cell particulate proteins corresponded to the most heavily labelled proteins of the isolated brush border membrane; and (c) brush border core proteins showed minimal radioactivity in vivo, but considerably higher radioactivity when brush border membranes were labelled in vitro. A small amount of label was absorbed across the intestinal mucosa. However, secondary labelling of brush border proteins by this absorbed label was minimal, since the specific activity of brush border proteins in jejunum adjacent to the labelled loop was only 0.22% of the level for those proteins in the labelled segment. Since this technique did not affect the cellular morphology, enzyme activity or biochemical integrity of the membrane, it should prove useful as a means of accurately studying in vivo turnover rates of brush border membrane proteins.

A randomized trial of the effects of early cardiac serum marker availability on reperfusion therapy in patients with acute myocardial infarction: the serial markers, acute myocardial infarction and rapid treatment trial (SMARTT).

OBJECTIVES: The purpose of this study was to assess whether the immediate availability of serum markers would increase the appropriate use of thrombolytic therapy. BACKGROUND: Serum markers such as myoglobin and creatine kinase, MB fraction (CK-MB) are effective in detecting acute myocardial infarction (AMI) in the emergency setting. Appropriate candidates for thrombolytic therapy are not always identified in the emergency department (ED), as 20% to 30% of eligible patients go untreated, representing 10% to 15% of all patients with AMI. Patients presenting with chest pain consistent with acute coronary syndrome were evaluated in the EDs of 12 hospitals throughout North America. METHODS: In this randomized, controlled clinical trial, physicians received either the immediate myoglobin/CK-MB results at 0 and 1 h after enrollment (stat) or conventional reporting of myoglobin/CK-MB 3 h or more after hospital admission (control). The primary end point was the comparison of the proportion of patients within the stat group versus control group who received appropriate thrombolytic therapy. Secondary end points included the emergent use of any reperfusion treatment in both groups, initial hospital disposition of patients (coronary care unit, monitor or nonmonitor beds) and the proportion of patients appropriately discharged from the ED. RESULTS: Of 6,352 patients enrolled, 814 (12.8%) were diagnosed as having AMI. For patients having AMI, there were no statistically significant differences in the proportion of patients treated with thrombolytic therapy between the stat and control groups (15.1% vs. 17.1%, p = 0.45). When only patients with ST segment elevation on their initial electrocardiogram were compared, there were still no significant differences between the groups. Also, there was no difference in the hospital placement of patients in critical care and non- critical care beds. The availability of early markers was associated with more hospital admissions as compared to the control group, as the number of patients discharged from the ED was decreased in the stat versus control groups (28.4% vs. 31.5%, p = 0.023). CONCLUSIONS: The availability of 0- and 1-h myoglobin and CK-MB results after ED evaluation had no effect on the use of thrombolytic therapy for patients presenting with AMI, and it slightly increased the number of patients admitted to the hospital who had no evidence of acute myocardial necrosis.

Treatment and survival from colorectal cancer: the experience of patients at South Australian teaching hospitals between 1980 and 2002.

AIMS: To evaluate trends in colorectal cancer survival and treatment at South Australian teaching hospitals and degree of adherence to treatment guidelines which recommend adjuvant chemotherapy for Dukes' C colon cancers and combined chemotherapy and radiotherapy for high-risk rectal cancers. MATERIALS AND METHODS: Trends in disease specific survival and primary treatment were analysed, and comparisons drawn between diagnostic epochs, using cancer registry data from South Australian teaching hospitals. Statistical methods included univariate and multivariable disease specific survival analyses. RESULTS: Five-year survival increased from 48% in 1980-1986 to 56% in 1995-2002. Largest gains were for stage C, where survivals were higher when chemotherapy was part of the primary treatment. By comparison, gains in 1-year survival were largest for stage D. Chemotherapy was provided for 4% of patients with colorectal cancers in 1980-1986, increasing to 32% in 1995-2002. Among stage C cases below 70 years at diagnosis, the proportion having chemotherapy increased to 83% in 1995-2002. The most common chemotherapy was fluorouracil (5FU) as a single agent in 1980-1986 and 5FU with leucovorin in 1995-2002. As expected, radiotherapy was used more frequently for rectal than colon cancers, and particularly for stage C. Among stage C rectal cases below 70 years, the proportion having radiotherapy increased from 10% in 1980-1986 to 57% in 1995-2002. Approximately 93% of colorectal cancers were treated surgically. Patients not treated surgically tended to be aged 80 years or more and to present with distant metastases. CONCLUSIONS: Trends in chemotherapy and radiotherapy accord with evidence-based recommendations. There have been reassuring gains in survivals after adjusting for stage, grade and other prognostic indicators. The data show survival gains and treatment patterns that individual hospitals can use as benchmarks when evaluating their own experience.

Sertoli cell-only syndrome produced by cold testicular ischemia.

This report describes a new method for producing Sertoli cell-only testes in the Lewis rat using 90 min of hypothermic testicular ischemia. The method employs selective occlusion of the testicular blood supply using atraumatic microclips applied with the aid of an operating microscope. The testis is packed in ice-cold saline throughout the ischemic interval, and the deferential artery and vein are ligated. Twelve weeks after the ischemic insult, the testes weigh half that of control testes while there were no differences in prostate or seminal vesicle weights. Microscopic examination of the ischemic damaged testes revealed normal-appearing Leydig and Sertoli cells, but complete absence of germ cells. Assays of testicular enzyme activities indicated that lactic dehydrogenase and sorbitol dehydrogenase were reduced, while alpha-glutamyl transpeptidase activity was normal, consistent with the marked reduction of germ cells. Serum androgen binding protein (rABP) levels were elevated relative to nonischemic controls. By contrast, serum concentrations of testosterone, LH, and FSH were normal. In addition, LHRH elicited identical LH and testosterone responses in control and experimental animals. Testicular blood flow measured with 133Xenon was slightly decreased in Sertoli-cell-only testes. Intratesticular temperatures was normal in all groups. These observations in rats with ischemia-induced Sertoli-cell-only testes are strikingly different from those induced by radiation or genetic defects. Animals with these latter disorders have elevated FSH levels, evidence of altered Leydig cell function as evidenced by elevated LH or abnormal response to LHRH; and normal or low serum rABP levels. We conclude that 1) ischemia produces no abnormalities of the pituitary testicular axis in spite of marked germ cell depletion and 2) Sertoli-cell-only testes of different etiologies can have varied patterns of hormone and rABP secretion.

Potential regulators of feeding behavior in anorexia nervosa.

We recruited 10 patients with anorexia nervosa and 6 age- and height-matched control subjects. Basal and postprandial concentrations of glucose, insulin, cholesterol, amino acids, gastrin, and pancreatic polypeptide (PP) were measured in response to a standard mixed meal. The only satiety signal that was significantly different between the anorectic group and the control group was PP (P less than 0.001). Tryptophan-LNAA and tyrosine-LNAA ratios were not significantly different in the two groups; however, there was a trend toward a lower tryptophan-LNAA ratio in the anorectic group. Gastrin concentrations were significantly decreased in the anorectic group (P less than 0.001) as were basal insulin concentrations (P less than 0.05). Decreased gastrin concentrations may play a role in the gastric symptoms associated with anorexia nervosa. Previous findings that PP release is diminished in obesity, together with the present findings of PP increase in anorexia nervosa, suggest that this peptide may play a role in appetite control mechanisms.

Effect of resistant starch on fecal bulk and fermentation-dependent events in humans.

This study investigated the effect of two diets, which differed in resistant starch (RS) concentration, on fecal bulk and fermentation-dependent events in 11 humans. Amounts of RS consumed were 5.0 +/- 0.4 and 39.0 +/- 3.0 g/d (mean +/- SEM) for the low- and high-RS diets, respectively. The two diets were fed for 3 wk each in a randomized crossover design. Fecal collections were made in the third week of each study period. The high-RS diet produced an increase (P < 0.01) in total fecal output (from 138 +/- 22 to 197 +/- 37 g/d) and lowered fecal pH (6.9 +/- 0.1 to 6.3 +/- 0.1). There were significant increases (P < 0.05) in the fecal concentrations and daily excretion of butyrate (+38% and +100%, respectively) and acetate (+26% and +72%, respectively) during the high-RS period. The fecal excretion (g/d) of nonstarch polysaccharides (NSP) also rose by 50% during the high-RS diet, suggesting that the presence of starch in the colon may affect the fermentation of NSP. Subjects reported an increase in flatulence and easier defecation. These results demonstrate that RS has a significant impact on putative markers of colonic health in humans.

Resistant starch in the diet increases breath hydrogen and serum acetate in human subjects.

The colonic fermentation of two diets differing in amounts of resistant starch (RS) was studied. High- and low-RS diets were fed to eight healthy subjects in three meals for 1 d. Breath hydrogen and two blood samples were collected over a 28-h period. The high-RS diet provided 59.1 +/- 4.7 g (mean +/- SE) RS and the low-RS diet provided 5.2 +/- 0.4 g RS. Breath hydrogen and the average total serum acetate were significantly higher during the high-RS diet than during the low-RS diet: 34.1 +/- 4.7 and 23.9 +/- 3.9 ppm (P < 0.001) and 169.1 +/- 12.8 and 118 +/- 6.6 mumol/L (P < 0.01), respectively. Butyrate and propionate were also detected in serum samples. Although not statistically significant, there was a trend (P = 0.087) for butyrate to increase with the high-RS diet. Subjects reported greater gastrointestinal symptoms during the high-RS diet. These results suggest that RS may have effects comparable with those of some fermentable dietary fibers.

Modulation of fecal markers relevant to colon cancer risk: a high-starch Chinese diet did not generate expected beneficial changes relative to a Western-type diet.

In a randomized, crossover dietary intervention study, 12 Australians (of white descent) consumed a diet typical of low-income communities in China and an average Australian diet so that effects on fecal markers thought to be relevant to colon cancer risk could be compared. The Chinese diet contained 35.3 g starch/MJ daily [including 2 g resistant starch (RS)/MJ and 1.5 g nonstarch polysaccharides (NSPs)/MJ]; the Australian diet contained 12 g starch/MJ daily (including 0.8 g RS and 2.7 g NSPs/MJ). Subjects followed each diet for 3 wk. Serum cholesterol concentrations were significantly lower after the low-fat, high-starch Chinese diet than after the Australian diet (mean +/- SEM: 4.17 +/- 0.30 compared with 5.04 +/- 0.28 mmol/L, respectively, P < 0.05), a difference indicative of dietary compliance. Fecal pH was lower after the Chinese diet (6.51 +/- 0.04) than after the Australian diet (6.63 +/- 0.05; P < 0.05). For all other fecal markers examined, however, the Chinese diet produced less favorable changes, including lower fecal bulk (86 +/- 11 compared with 141 +/- 20 g wet wt/d, P < 0.01), slower transit through the gut (69 +/- 6 compared with 56 +/- 7 h, P = 0.06), lower fecal concentrations of short-chain fatty acids [72.8 +/- 7.3 compared with 98 +/- 7.6 mmol/L (including butyrate: 12.2 +/- 1.3 compared with 18.4 +/- 2.3 mmol/L), P < 0.05], and higher fecal concentrations of potentially damaging ammonia (540 +/- 50 compared with 450 +/- 40 mg/L, P < 0.01) and phenols (109.2 +/- 13.2 compared with 68.5 +/- 12.9 mg/L, P < 0.01). These results suggest that consumption of a high-starch diet alone is insufficient to reduce the risk of developing colon cancer.

The effect of incubation of rectal biopsies on measures of proliferation using proliferating cell nuclear antigen in comparison with 5-bromo-2-deoxyuridine.

Rectal epithelial cell kinetics are used as intermediate markers for colorectal cancer and relate to risk. In this study, measures of proliferation using direct immunohistochemistry for proliferating cell nuclear antigen (PCNA) were compared to in vitro labeling by bromodeoxyuridine (BrdUrd) and incubated biopsies that were later stained for PCNA (PCNA-I) in human rectal biopsies. The study group consisted of 20 sets of biopsies from 12 subjects participating in an intervention trial. Fresh nonincubated biopsies were fixed in methacarn and stained immunohistochemically for PCNA (clone 19A2). In parallel biopsies, BrdUrd was incorporated into the DNA of S-phase cells during a 2-h incubation at 37 degrees C under hyperbaric conditions and localized by immunohistochemistry. Additionally, biopsies were incubated under hyperbaric conditions for 2 h at 37 degrees C, fixed in methacarn, and stained for PCNA (PCNA-I). There was a highly significant difference in the labeling index between the three methods (P < 0.01), but there was no significant difference between subjects (P = 0.439). The mean labeling index was 2.3 +/- 0.1% for PCNA, 2.9 +/- 0.1% for PCNA-I, and 4.1 +/- 0.1% for BrdUrd. The proportion of labeled cells in the top two-fifths was significantly higher (P = 0.01) for BrdUrd (5.5 +/- 0.8%) and PCNA-I (6.4 +/- 1.1%) compared to PCNA (3.1 +/- 0.6%), and a significant difference was seen between subjects (P = 0.038). PCNA-I and BrdUrd methods had similar crypt heights with 73.5 +/- 1.8 and 71.2 +/- 1.3 cells/crypt column, respectively, but were significantly shorter (P < 0.001) than PCNA with 83.4 +/- 1.5 cells/crypt column, indicating a loss of cells during organ culture. The simplicity of the PCNA technique, which avoids potential perturbations occurring during organ culture, has considerable appeal as a marker for colorectal cancer risk, but additional studies are needed to correlate PCNA with neoplastic risk.