A synthetic approach to 'click' neoglycoprotein analogues of EPO employing one-pot native chemical ligation and CuAAC chemistry

The clinical significance of batch-wise variability on the pharmacokinetics and potency of commercial erythropoietin (EPO), prepared recombinantly as a heterogeneous mixture of glycoforms, necessitates the development of synthetic strategies to afford homogenous EPO formulations. Herein we present a previously unexplored and divergent route towards 'click' neoglycoprotein analogues of EPO, employing one-pot native chemical ligation (NCL) of alkynylated peptides and copper-catalysed azide-alkyne cycloaddition (CuAAC) with azido monosaccharides. By design, our synthetic platform permits glycosylation at virtually any stage, providing flexibility for the synthesis of various glycoforms for biological analysis. Insights obtained from attempted folding of our 'click' neoglycoprotein EPO analogue, bearing four different neutral sugar moieties, highlight the important role played by the charged oligosaccharides present in native EPO glycoproteins.

Protein kinase N1 critically regulates cerebellar development and long-term function

Increasing evidence suggests that synapse dysfunctions are a major determinant of several neurodevelopmental and neurodegenerative diseases. Here we identify protein kinase N1 (PKN1) as a novel key player in fine-tuning the balance between axonal outgrowth and presynaptic differentiation in the parallel fiber-forming (PF-forming) cerebellar granule cells (Cgcs). Postnatal Pkn1-/- animals showed a defective PF-Purkinje cell (PF-PC) synapse formation. In vitro, Pkn1-/- Cgcs exhibited deregulated axonal outgrowth, elevated AKT phosphorylation, and higher levels of neuronal differentiation-2 (NeuroD2), a transcription factor preventing presynaptic maturation. Concomitantly, Pkn1-/- Cgcs had a reduced density of presynaptic sites. By inhibiting AKT with MK-2206 and siRNA-mediated knockdown, we found that AKT hyperactivation is responsible for the elongated axons, higher NeuroD2 levels, and reduced density of presynaptic specifications in Pkn1-/- Cgcs. In line with our in vitro data, Pkn1-/- mice showed AKT hyperactivation, elevated NeuroD2 levels, and reduced expression of PF-PC synaptic markers during stages of PF maturation in vivo. The long-term effect of Pkn1 knockout was further seen in cerebellar atrophy and mild ataxia. In summary, our results demonstrate that PKN1 functions as a developmentally active gatekeeper of AKT activity, thereby fine-tuning axonal outgrowth and presynaptic differentiation of Cgcs and subsequently the correct PF-PC synapse formation.

Uncoupling TORC2 from AGC kinases inhibits tumour growth

Mammalian target of rapamycin (mTOR) is a central regulator of growth and metabolism. mTOR resides in two distinct multi-protein complexes - mTORC1 and mTORC2 - with distinct upstream regulators and downstream targets. While it is possible to specifically inhibit mTORC1 with rapamycin, or inhibit both mTOR complexes together with ATP pocket directed mTOR kinase inhibitors, it is not possible to assess the specific roles for mTORC2 pharmacologically. To overcome this, we have developed a novel, inducible, dominant negative system for disrupting substrate recruitment to mTORC2. Previously we identified the mTORC2 specific subunit Sin1 as a direct binding partner for AGC kinases Akt and PKC. Sin1 mutants, which retain the ability to bind Rictor and mTOR, but fail to recruit their AGC client kinases, inhibit AKT and PKC priming and block cell growth. In this study, we demonstrate that uncoupling mTORC2 from AGC kinases in DLD1 colon cancer cells inhibits Akt activation and blocks tumour growth in vivo. Further we demonstrate, using time resolved two-site amplified FRET (A-FRET) analysis of xenograft tumours, that inhibition of tumour growth correlates with the degree of mTORC2 uncoupling from its downstream targets, as demonstrated for Akt. These data add weight to the body of evidence that mTORC2 represents a pharmacological target in cancer independently of mTORC1.

Effect of changes to the school food environment on eating behaviours and/or body weight in children: a systematic review

Previous school obesity-prevention reviews have included multi-component interventions. Here, we aimed to review the evidence for the effect of isolated food environment interventions on both eating behaviours (including food purchasing) and/or body weight. Five electronic databases were searched (last updated 30 November 2013). Of the 1,002 unique papers identified, 55 reported on school food environment changes, based on a review of titles and abstracts. Thirty-seven further papers were excluded, for not meeting the inclusion criteria. The final selection consisted of 18 papers (14 United States, 4 United Kingdom). Two studies had a body mass index (BMI) outcome, 14 assessed purchasing or eating behaviours and two studies assessed both weight and behaviour. Seventeen of 18 papers reported a positive outcome on either BMI (or change in BMI) or the healthfulness of food sold or consumed. Two studies were rated as strong quality and 11 as weak. Only three studies included a control group. A school environment supportive of healthy eating is essential to combat heavy marketing of unhealthy food. Modification of the school food environment (including high-level policy changes at state or national level) can have a positive impact on eating behaviours. A need exists, however, for further high-quality studies.

Targeting protein kinase C in sarcoma

Protein kinase C (PKC) is a family of serine/threonine tyrosine kinases that regulate many cellular processes including division, proliferation, survival, anoikis and polarity. PKC is abundant in many human cancers and aberrant PKC signalling has been demonstrated in cancer models. On this basis, PKC has become an attractive target for small molecule inhibition within oncology drug development programmes. Sarcoma is a heterogeneous group of mesenchymal malignancies. Due to their relative insensitivity to conventional chemotherapies and the increasing recognition of the driving molecular events of sarcomagenesis, sarcoma provides an excellent platform to test novel therapeutics. In this review we provide a structure-function overview of the PKC family, the rationale for targeting these kinases in sarcoma and the state of play with regard to PKC inhibition in the clinic.

Regulation of polarized morphogenesis by protein kinase C iota in oncogenic epithelial spheroids

Protein kinase C iota (PKCι), a serine/threonine kinase required for cell polarity, proliferation and migration, is commonly up- or downregulated in cancer. PKCι is a human oncogene but whether this is related to its role in cell polarity and what repertoire of oncogenes acts in concert with PKCι is not known. We developed a panel of candidate oncogene expressing Madin-Darby canine kidney (MDCK) cells and demonstrated that H-Ras, ErbB2 and phosphatidylinositol 3-kinase transformation led to non-polar spheroid morphogenesis (dysplasia), whereas MDCK spheroids expressing c-Raf or v-Src were largely polarized. We show that small interfering RNA (siRNA)-targeting PKCι decreased the size of all spheroids tested and partially reversed the aberrant polarity phenotype in H-Ras and ErbB2 spheroids only. This indicates distinct requirements for PKCι and moreover that different thresholds of PKCι activity are required for these phenotypes. By manipulating PKCι function using mutant constructs, siRNA depletion or chemical inhibition, we have demonstrated that PKCι is required for polarization of parental MDCK epithelial cysts in a 3D matrix and that there is a threshold of PKCι activity above and below which, disorganized epithelial morphogenesis results. Furthermore, treatment with a novel PKCι inhibitor, CRT0066854, was able to restore polarized morphogenesis in the dysplastic H-Ras spheroids. These results show that tightly regulated PKCι is required for normal-polarized morphogenesis in mammalian cells and that H-Ras and ErbB2 cooperate with PKCι for loss of polarization and dysplasia. The identification of a PKCι inhibitor that can restore polarized morphogenesis has implications for the treatment of Ras and ErbB2 driven malignancies.

Progress in a replicated selection for elevated blood ethanol concentrations in HDID mice

Drinking in the dark (DID) is a limited access ethanol-drinking phenotype in mice. High Drinking in the Dark (HDID-1) mice have been bred for 27 selected generations (S27) for elevated blood ethanol concentrations (BECs) after a 4-h period of access to 20% ethanol. A second replicate line (HDID-2) was started later from the same founder population and is currently in S20. An initial report of response to selection in HDID-1 was published after S11. This article reports genetic and behavioral characteristics of both lines in comparison with the HS controls. Heritability is low in both replicates (h(2)  = 0.09) but the lines have shown 4-5 fold increases in BEC since S0; 80% of HDID-1 and 60% of HDID-2 mice reach BECs greater than 1.0 mg/ml. Several hours after a DID test, HDID mice show mild signs of withdrawal. Although not considered during selection, intake of ethanol (g/kg) during the DID test increased by approximately 80% in HDID-1 and 60% in HDID-2. Common genetic influences were more important than environmental influences in determining the similarity between BEC and intake for HDID mice. Analysis of the partitioning of intake showed that 60% of intake is concentrated in the last 2 h of the 4 h session. However, this has not changed during selection. Hourly BECs during the DID test reach peak levels after 3 or 4 h of drinking. HDID mice do not differ from HS mice in their rate of elimination of an acute dose of alcohol.

Monitoring the availability of healthy and unhealthy foods and non-alcoholic beverages in community and consumer retail food environments globally

Retail food environments are increasingly considered influential in determining dietary behaviours and health outcomes. We reviewed the available evidence on associations between community (type, availability and accessibility of food outlets) and consumer (product availability, prices, promotions and nutritional quality within stores) food environments and dietary outcomes in order to develop an evidence-based framework for monitoring the availability of healthy and unhealthy foods and non-alcoholic beverages in retail food environments. Current evidence is suggestive of an association between community and consumer food environments and dietary outcomes; however, substantial heterogeneity in study designs, methods and measurement tools makes it difficult to draw firm conclusions. The use of standardized tools to monitor local food environments within and across countries may help to validate this relationship. We propose a step-wise framework to monitor and benchmark community and consumer retail food environments that can be used to assess density of healthy and unhealthy food outlets; measure proximity of healthy and unhealthy food outlets to homes/schools; evaluate availability of healthy and unhealthy foods in-store; compare food environments over time and between regions and countries; evaluate compliance with local policies, guidelines or voluntary codes of practice; and determine the impact of changes to retail food environments on health outcomes, such as obesity.

Television in the bedroom and increased body weight: potential explanations for their relationship among European schoolchildren

AIMS

A television in the bedroom is associated with measures of adiposity. We aimed to test if this association is mediated by any of (i) time spent watching television, (ii) sleep duration, (iii) physical activity level or (iv) consumption of soft drinks.

METHOD

Data were from 7234 boys and girls aged 10-12 years in European countries involved in the EuropeaN Energy balance Research to prevent excessive weight Gain among Youth project (Belgium, Greece, Hungary, the Netherlands, Norway, Slovenia and Spain). Waist circumference, height and weight were measured. The presence of a bedroom television, television viewing time, sleep duration, physical activity time and soft drink consumption were assessed by standardized questionnaires.

RESULTS

Almost 40% of schoolchildren had a bedroom television, with the highest percentage among Hungarian children (65%) and lowest for Belgian, Slovenian and Spanish children (all ≈28%). A television in the bedroom was positively associated with time spent watching television, soft drink consumption and overweight and obesity (all P < 0.001). The relationship between a television in the bedroom and measures of body size was partly mediated by total television viewing time (proportion mediated for waist circumference 8.9%; for body mass index 8.3%) but not sleep duration, physical activity time or soft drink consumption.

CONCLUSION

The strong association between a television in the bedroom and adiposity was at least partially mediated by television viewing time. The large proportion of European schoolchildren with a television in their bedroom is of concern. Parents should be aware of the potential consequences when placing a television in a child's bedroom and children should limit viewing time.

A systematic review of the impact of including both waist and hip circumference in risk models for cardiovascular diseases, diabetes and mortality

Both a larger waist and narrow hips are associated with heightened risk of diabetes, cardiovascular diseases and premature mortality. We review the risk of these outcomes for levels of waist and hip circumferences when terms for both anthropometric measures were included in regression models. MEDLINE and EMBASE were searched (last updated July 2012) for studies reporting the association with the outcomes mentioned earlier for both waist and hip circumferences (unadjusted and with both terms included in the model). Ten studies reported the association between hip circumference and death and/or disease outcomes both unadjusted and adjusted for waist circumference. Five studies reported the risk associated with waist circumference both unadjusted and adjusted for hip circumference. With the exception of one study of venous thromboembolism, the full strength of the association between either waist circumference or hip circumference with morbidity and/or mortality was only apparent when terms for both anthropometric measures were included in regression models. Without accounting for the protective effect of hip circumference, the effect of obesity on risk of death and disease may be seriously underestimated. Considered together (but not as a ratio measure), waist and hip circumference may improve risk prediction models for cardiovascular disease and other outcomes.

Socioeconomic variation in diet and activity-related behaviours of Australian children and adolescents aged 2-16 years

BACKGROUND

Evidence for age-related variation in the relationship between obesity-related behaviours and socioeconomic position may assist in the targeting of dietary and physical activity interventions among children.

OBJECTIVE

To investigate the relationship between different indicators of socioeconomic position and obesity-related behaviours across childhood and adolescence.

METHODS

Data were from 4487 children aged 2 to 16 years participating in the cross-sectional 2007 Australian National Children's Nutrition and Physical Activity Survey. Socioeconomic position was defined by the highest education of the primary or secondary carer and parental income. Activity was assessed using recall methods with physical activity also assessed using pedometers. Intake of energy-dense drinks and snack foods, fruits and vegetables was assessed using 2 × 24-h dietary recalls.

RESULTS

A socioeconomic gradient was evident for each dietary measure (although in age-specific analyses, not for energy-dense snacks in older children), as well as television viewing, but not physical activity. Whether each behaviour was most strongly related to parental income or education of the primary or secondary carer was age and sex dependent. The socioeconomic gradient was strongest for television viewing time and consumption of fruit and energy-dense drinks.

CONCLUSIONS

A strong socioeconomic gradient in eating behaviours and television viewing time was observed. Relationships for particular behaviours differed by age, sex and how socioeconomic position was defined. Socioeconomic indicators define different population groups and represent different components of socioeconomic position. These findings may provide insights into who should be targeted in preventive health efforts at different life stages.

Higher leptin levels in Asian Indians than Creoles and Europids: a potential explanation for increased metabolic risk

BACKGROUND AND PURPOSE

Leptin predicts cardiovascular diseases and type 2 diabetes, diseases to which Asian Indians are highly susceptible. As a risk marker, leptin's intra-individual and seasonal stability is unstudied and only small studies have compared leptin levels in Asian Indians with other populations. The aim of this study was to explore ethnicity related differences in leptin levels and its intra-individual and seasonal stability.

METHODS

Leptin and anthropometric data from the northern Sweden MONICA (3513 Europids) and the Mauritius Non-communicable Disease (2480 Asian Indians and Creoles) studies were used. In both studies men and women, 25- to 74-year old, participated in both an initial population survey and a follow-up after 5-13 years. For the analysis of seasonal leptin variation, a subset of 1780 participants, 30- to 60-year old, in the Västerbotten Intervention Project was used.

RESULTS

Asian Indian men and women had higher levels of leptin, leptin per body mass index (BMI) unit (leptin/BMI) or per cm in waist circumference (WC; leptin/waist) than Creoles and Europids when adjusted for BMI (all P<0.0005) or WC (all P<0.005). In men, Creoles had higher leptin, leptin/BMI and leptin/waist than Europids when adjusted for BMI or WC (all P<0.0005). In women, Creoles had higher leptin/BMI and leptin/waist than Europids only when adjusted for WC (P<0.0005). Asian Indian ethnicity in both sexes, and Creole ethnicity in men, was independently associated with high leptin levels. The intra-class correlation for leptin was similar (0.6-0.7), independently of sex, ethnicity or follow-up time. No seasonal variation in leptin levels was seen.

CONCLUSION

Asian Indians have higher levels of leptin, leptin/BMI and leptin/waist than Creoles and Europids. Leptin has a high intra-individual stability and seasonal leptin variation does not appear to explain the ethnic differences observed here.

Television viewing time and mortality: the Australian Diabetes, Obesity and Lifestyle Study (AusDiab)

BACKGROUND

Television viewing time, the predominant leisure-time sedentary behavior, is associated with biomarkers of cardiometabolic risk, but its relationship with mortality has not been studied. We examined the associations of prolonged television viewing time with all-cause, cardiovascular disease (CVD), cancer, and non-CVD/noncancer mortality in Australian adults.

METHODS AND RESULTS

Television viewing time in relation to subsequent all-cause, CVD, and cancer mortality (median follow-up, 6.6 years) was examined among 8800 adults > or =25 years of age in the Australian Diabetes, Obesity and Lifestyle Study (AusDiab). During 58 087 person-years of follow-up, there were 284 deaths (87 CVD deaths, 125 cancer deaths). After adjustment for age, sex, waist circumference, and exercise, the hazard ratios for each 1-hour increment in television viewing time per day were 1.11 (95% confidence interval [CI], 1.03 to 1.20) for all-cause mortality, 1.18 (95% CI, 1.03 to 1.35) for CVD mortality, and 1.09 (95% CI, 0.96 to 1.23) for cancer mortality. Compared with a television viewing time of <2 h/d, the fully adjusted hazard ratios for all-cause mortality were 1.13 (95% CI, 0.87 to 1.36) for > or =2 to <4 h/d and 1.46 (95% CI, 1.04 to 2.05) for > or =4 h/d. For CVD mortality, corresponding hazard ratios were 1.19 (95% CI, 0.72 to 1.99) and 1.80 (95% CI, 1.00 to 3.25). The associations with both cancer mortality and non-CVD/noncancer mortality were not significant.

CONCLUSIONS

Television viewing time was associated with increased risk of all-cause and CVD mortality. In addition to the promotion of exercise, chronic disease prevention strategies could focus on reducing sitting time, particularly prolonged television viewing.

HOMA insulin sensitivity index and the risk of all-cause mortality and cardiovascular disease events in the general population: the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) study

AIMS/HYPOTHESIS

We assessed whether the relationships between insulin sensitivity and all-cause mortality as well as fatal or non-fatal cardiovascular disease (CVD) events are independent of elevated blood glucose, high blood pressure, dyslipidaemia and body composition in individuals without diagnosed diabetes.

METHODS

Between 1999 and 2000, baseline fasting insulin, glucose and lipids, 2 h plasma glucose, HbA(1c), anthropometrics, blood pressure, medication use, smoking and history of CVD were collected from 8,533 adults aged >35 years from the population-based Australian Diabetes, Obesity and Lifestyle study. Insulin sensitivity was estimated by HOMA of insulin sensitivity (HOMA-%S). Deaths and fatal or non-fatal CVD events were ascertained through linkage to the National Death Index and medical records adjudication.

RESULTS

After a median of 5.0 years there were 277 deaths and 225 CVD events. HOMA-%S was not associated with all-cause mortality. Compared with the most insulin-sensitive quintile, the combined fatal or non-fatal CVD HR (95% CI) for quintiles of decreasing HOMA-%S were 1.1 (0.6-1.9), 1.4 (0.9-2.3), 1.6 (1.0-2.5) and 2.0 (1.3-3.1), adjusting for age and sex. Smoking, CVD history, hypertension, lipid-lowering medication, total cholesterol and waist-to-hip ratio moderately attenuated this relationship. However, the association was rendered non-significant by adding HDL. Fasting plasma glucose, but not HOMA-%S significantly improved the prediction of CVD, beyond that seen with other risk factors.

CONCLUSIONS/INTERPRETATION

In this cohort, HOMA-%S showed no association with all-cause mortality and only a modest association with CVD events, largely explained by its association with HDL. Fasting plasma glucose was a better predictor of CVD than HOMA-%S.

The metabolic syndrome: in need of a global mission statement

AIMS

The value of clinical definitions of the metabolic syndrome has been questioned, with confusion surrounding their intended use and purpose. Our aim was to construct a mission statement that outlines the value of the metabolic syndrome in clinical and public health settings.

METHODS

Case studies have been used to demonstrate three key points.

RESULTS

We argue here for recognition of obesity as being a crucial element within the metabolic syndrome but perhaps even more important before its development. We also contend that the concept does indeed have a role as a risk prediction tool, and that it could provide a useful metric for the scale and progress of the looming global epidemic of diabetes and cardiovascular disease.

CONCLUSIONS

Through appreciation of its purpose, and recognition of both its limitations and those attributes that make it unique and valuable, we believe we have demonstrated here that the metabolic syndrome deserves its place in the global toolbox of diabetes and CVD prevention.

The metabolic syndrome as a tool for predicting future diabetes: the AusDiab study

OBJECTIVE

To compare the ability of the metabolic syndrome (MetS), a diabetes prediction model (DPM), a noninvasive risk questionnaire and individual glucose measurements to predict future diabetes.

DESIGN

Five-year longitudinal cohort study. Tools tested included MetS definitions [World Health Organization, International Diabetes Federation, ATPIII and European Group for the study of Insulin Resistance (EGIR)], the FINnish Diabetes RIsk SCore risk questionnaire, the DPM, fasting and 2-h post load plasma glucose.

SETTING

Adult Australian population.

SUBJECTS

A total of 5842 men and women without diabetes > or =25 years. Response 58%. A total of 224 incident cases of diabetes.

RESULTS

In receiver operating characteristic curve analysis, the MetS was not a better predictor of incident diabetes than the DPM or measurement of glucose. The risk for diabetes among those with prediabetes but not MetS was almost triple that of those with MetS but not prediabetes (9.0% vs. 3.4%). Adjusted for component parts, the MetS was not a significant predictor of incident diabetes, except for EGIR in men [OR 2.1 (95% CI 1.2-3.7)].

CONCLUSIONS

A single fasting glucose measurement may be more effective and efficient than published definitions of the MetS or other risk constructs in predicting incident diabetes. Diagnosis of the MetS did not confer increased risk for incident diabetes independent of its individual components, with an exception for EGIR in men. Given these results, debate surrounding the public health utility of a MetS diagnosis, at least for identification of incident diabetes, is required.

Differences in height explain gender differences in the response to the oral glucose tolerance test- the AusDiab study

AIM

To determine the extent of gender-related differences in the prevalence of glucose intolerance for the Australian population and whether body size may explain such differences.

METHODS

Cross-sectional data were collected from a national cohort of 11 247 Australians aged > or = 25 years. Glucose tolerance status was assessed according to both fasting plasma glucose (FPG) and 2-h plasma glucose (2hPG) levels following a 75-g oral glucose tolerance test (OGTT). Anthropometric and glycated haemoglobin measurements were also made.

RESULTS

Undiagnosed diabetes and non-diabetic glucose abnormalities were more prevalent among men than women when based only on the FPG results (diabetes: men 2.2%, women 1.6%, P = 0.02; impaired fasting glycaemia: men 12.3%, women 6.6%, P < 0.001). In contrast 16.0% of women and 13.0% of men had a 2hPG abnormality (either diabetes or impaired glucose tolerance, P = 0.14). Women had a mean FPG 0.3 mmol/l lower than men (P < 0.001), but 2hPG 0.3 mmol/l higher (P = 0.002) and FPG-2hPG increment 0.5 mmol/l greater (P < 0.001). The gender difference in mean 2hPG and FPG-2hPG increment disappeared following adjustment for height. For both genders, those in the shortest height quartile had 2hPG levels 0.5 mmol/l higher than the tallest quartile, but height showed almost no relationship with the FPG.

CONCLUSIONS

Men and women had different glycaemic profiles; women had higher mean 2hPG levels, despite lower fasting levels. It appeared that the higher 2hPG levels for women related to lesser height and may be a consequence of using a fixed glucose load in the OGTT, irrespective of body size.

The metabolic syndrome as a predictor of incident diabetes mellitus in Mauritius

AIMS

To assess the utility of the metabolic syndrome (MetS) and a Diabetes Predicting Model as predictors of incident diabetes.

METHODS

A longitudinal survey was conducted in Mauritius in 1987 (n = 4972; response 80%) and 1992 (n = 3685; follow-up 74.2%). Diabetes status was retrospectively determined using 1999 World Health Organization (WHO) criteria. MetS was determined according to four definitions and sensitivity, positive predictive value (PPV), specificity and the association with incident diabetes before and after adjustment for MetS components calculated.

RESULTS

Of the 3198 at risk, 297 (9.2%) developed diabetes between 1987 and 1992. The WHO MetS definition had the highest prevalence (20.3%), sensitivity (42.1%) and PPV (26.8%) for prediction of incident diabetes, the strongest association with incident diabetes after adjustment for age and sex [odds ratio 4.6 (3.5-6.0)] and was the only definition to show a significant association after adjustment for its component parts (in men only). The low prevalence and sensitivity of the International Diabetes Federation (IDF) and ATPIII MetS definitions resulted from waist circumference cut-points that were high for this population, particularly in men, and both were not superior to a diabetes predicting model on receiver operating characteristic analysis.

CONCLUSIONS

Of the MetS definitions tested, the WHO definition best identifies those who go on to develop diabetes, but is not often used in clinical practice. If cut-points or measures of obesity appropriate for this population were used, the IDF and ATPIII MetS definitions could be recommended as useful tools for prediction of diabetes, given their relative simplicity.

Is grand multiparity associated with an increased risk of dysglycaemia?

AIMS/HYPOTHESIS

We sought to determine the risk of diabetes and IGT/IFG with grand multiparity.

SUBJECTS, MATERIALS AND METHODS

Women, aged > or =25 years, from the Australian Diabetes, Obesity and Lifestyle Study and the Crossroads Undiagnosed Disease Study (a rural study in Victoria, Australia), participated in a household census (response 67 and 70%, respectively), subsequently attending a biomedical examination that included an oral glucose tolerance test (58% [6198] and 69% [819]).

RESULTS

After adjusting for age, obesity and socio-economic status, diabetes, but not IGT/IFG, was less common among women with a parity of 1 to 2 (odds ratio [OR]=0.64 [0.48-0.84]) and 3 to 4 (OR=0.72 [0.53-0.96]) than in grand multiparous women. This relationship was unrelated to past hysterectomy, use of the oral contraceptive pill or menopausal status.

CONCLUSIONS/INTERPRETATION

Grand multiparity is associated with an increased risk of diabetes but not of IGT/IFG. We postulate that parity accelerates transition from IGT/IFG to diabetes, more than it does transition from normal glucose tolerance to IGT/IFG.

Associations of TV viewing and physical activity with the metabolic syndrome in Australian adults

AIMS/HYPOTHESIS

We analysed a sample of Australian adults to determine the strength of associations of TV viewing and participation in physical activity with the metabolic syndrome.

METHODS

This population-based cross-sectional study included 6,241 adults aged > or =35 years who were free from diagnosed diabetes mellitus and self-reported ischaemic disease and were not taking lipid-lowering or antihypertensive drugs. The metabolic syndrome was defined according to the 1999 World Health Organization criteria. Participants self-reported TV viewing time and physical activity time for the previous week.

RESULTS

The adjusted odds ratio of having the metabolic syndrome was 2.07 (95% CI 1.49-2.88) in women and 1.48 (95% CI 0.95-2.31) in men who watched TV for >14 h per week compared with those who watched < or =7.0 h per week. Compared with those who were less active (<2.5 h per week), the odds ratio for the metabolic syndrome was 0.72 (95% CI 0.58-0.90) in men and 0.53 (95% CI 0.38-0.74) in women who were active (> or =2.5 h per week). Longer TV viewing (>14 h per week) was associated with an increased risk of insulin resistance, obesity and dyslipidaemia in both men and women. A total physical activity time of > or =2.5 h per week was associated with a reduced prevalence of both insulin resistance and dyslipidaemia in both sexes and reduced prevalence of both obesity and hypertension in women.

CONCLUSIONS/INTERPRETATION

Increased TV viewing time was associated with an increased prevalence of the metabolic syndrome, while physical activity was associated with a reduced prevalence. Population strategies addressing the metabolic syndrome should focus on reducing sedentary behaviours such as TV viewing, as well as increasing physical activity.

Relationship between body mass index, diet, exercise and gastro-oesophageal reflux symptoms in a community

BACKGROUND

Body mass index (BMI) is a risk factor for gastro-oesophageal reflux but may simply be explained by diet and lifestyle.

AIM

We aimed to determine the contribution of BMI, diet and exercise to GER.

METHODS

Community subjects (n = 211, mean age = 36 years, 43% males) completed validated questionnaires on gastro-oesophageal reflux, energy expenditure (Harvard Alumni Activity Survey), dietary intake (Harvard Food Frequency Questionnaire) and measures of personality and life event stress. Diet, exercise, BMI and other potential risk factors for reflux were analysed using logistic regression analyses.

RESULTS

The overall mean (+/- s.d.) BMI was 26.6 (+/- 5.7); 79 (37%) reported infrequent (< weekly) reflux and 16 (8%) reported frequent (> or = weekly) reflux. The median caloric intake was 2097 cal/day and the median daily energy expenditure was 1753 cal/day. Among those with BMI > 25, 10% reported frequent reflux compared to 4% of those with BMI < or = 25. In a model which included age, sex and Symptom Checklist-90 somatisation T-score, BMI was associated with reflux (OR per 5 units = 1.9, 95% CI: 1.2, 3.0). In models which included diet and exercise variables, BMI but not diet or exercise was associated with reflux.

CONCLUSION

BMI may be associated with symptomatic gastro-oesophageal reflux independent of diet and exercise.

Waist circumference, waist-hip ratio and body mass index and their correlation with cardiovascular disease risk factors in Australian adults

OBJECTIVES

To compare body mass index (BMI), waist circumference and waist-hip ratio (WHR) as indices of obesity and assess the respective associations with type 2 diabetes, hypertension and dyslipidaemia.

DESIGN AND SETTING

A national sample of 11 247 Australians aged > or =25 years was examined in 2000 in a cross-sectional survey.

MAIN OUTCOME MEASURES

The examination included a fasting blood sample, standard 2-h 75-g oral glucose tolerance test, blood pressure measurements and questionnaires to assess treatment for dyslipidaemia and hypertension. BMI, waist circumference and WHR were measured to assess overweight and obesity.

RESULTS

The prevalence of obesity amongst Australian adults defined by BMI, waist circumference and WHR was 20.8, 30.5 and 15.8% respectively. The unadjusted odds ratio for the fourth vs. first quartile of each obesity measurement showed that WHR had the strongest relationship with type 2 diabetes, dyslipidaemia (women only) and hypertension. Following adjustment for age, however, there was little difference between the three measures of obesity, with the possible exceptions of hypertension in women, where BMI had a stronger association, and dyslipidaemia in women and type 2 diabetes in men, where WHR was marginally superior.

CONCLUSIONS

Waist circumference, BMI and WHR identified different proportions of the population, as measured by both prevalence of obesity and cardiovascular disease (CVD) risk factors. Whilst WHR had the strongest correlations with CVD risk factors before adjustment for age, the three obesity measures performed similarly after adjustment for age. Given the difficulty of using age-adjusted associations in the clinical setting, these results suggest that given appropriate cut-off points, WHR is the most useful measure of obesity to use to identify individuals with CVD risk factors.

Gender differences in the prevalence of impaired fasting glycaemia and impaired glucose tolerance in Mauritius. Does sex matter?

OBJECTIVE

To examine gender differences in the characteristics and prevalence of various categories of glucose tolerance in a population study in Mauritius.

RESEARCH DESIGN AND METHODS

In 1998, a community-based cross-sectional survey was conducted in Mauritius. Categories of glucose metabolism were determined in 5388 adults, with an oral glucose tolerance test given to those who did not have previously diagnosed diabetes (n=4036). Other cardiovascular risk factors were assessed among those without known diabetes.

RESULTS

For men and women the prevalence of diabetes (22.0 vs. 21.8%, respectively) and the prevalence of coexisting impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) (3.2 vs. 2.9%) were similar. However, men were twice as likely as women to have isolated IFG [5.1% (4.2-6.0) vs. 2.9% (2.3-3.5)], despite being younger, thinner and with lower plasma insulin but higher lipids. Conversely, the prevalence of isolated IGT was lower in men [9.0% (7.9-10.2) vs. 13.9% (12.6-15.1)]. Among non-diabetic individuals, fasting glucose was higher in men than women, whereas 2-h glucose was higher in women. In people without diabetes, women had significantly higher body mass index, beta cell function (HOMA-B), fasting and 2-h insulin than men and significantly lower waist-hip ratios, waist circumference, insulin sensitivity (HOMA-S) and triglycerides.

CONCLUSION

In Mauritius, the distribution of impaired glucose metabolism differs by sex. The observation that IFG is more prevalent in men and IGT more prevalent in women raises important questions about their underlying aetiology and the ability of the current glucose thresholds to equally identify men and women at high-risk of developing diabetes. IFG should be seen as a complimentary category of abnormal glucose tolerance, rather than a replacement for IGT.

Strain differences in three measures of ethanol intoxication in mice: the screen, dowel and grip strength tests

Mice from 8 to 21 inbred strains were tested for sensitivity to ethanol intoxication using a range of doses and three different measures: the screen test, the dowel test and a test of grip strength. Strains differed under nearly all conditions. For the dowel test, two dowel widths were employed, and mice were tested immediately or 30 min after ethanol. For the dowel and screen tests, low doses failed to affect some strains, and the highest doses failed to discriminate among mice, maximally affecting nearly all. For grip strength, a single ethanol dose was used, and mice of all strains were affected. Pharmacokinetic differences among strains were significant, but these could not account for strain differences in intoxication. For doses and test conditions in the middle range, there were only modest correlations among strain means within a test. In addition, genotypic correlations across tests were modest to quite low. These results suggest that different specific versions of a test reflect the influence of different genes, and that genetic influences on different tests were also distinct.

Differential recruitment of accessory molecules by FcgammaRI during monocyte differentiation

Aggregation of the human high-affinity receptor for immunoglobulin G, FcgammaRI, results in initiation of intracellular signaling cascades. However, as the receptor contains no known signaling motif, it is required to recruit an accessory molecule. The gamma chain has been proposed to fulfil this role. Here, we show that in U937 cells differentiated to a more macrophage-like phenotype with dibutyryl cAMP, FcgammaRI no longer signals through the gamma chain but rather uses FcgammaRIIa to initiate tyrosine phosphorylation. Expression of the gamma chain is, however, increased in the dbcAMP-induced cells, but here the gamma chain specifically associates with the IgA receptor, FcalphaRI. Recruitment of the gamma chain either by FcgammaRI in cytokine-primed cells or by FcalphaRI in dbcAMP-induced cells couples ligand binding to the activation of phosphatidyl choline-specific phospholipase D.

Secular trends in the epidemiology and outcome of Barrett's oesophagus in Olmsted County, Minnesota

BACKGROUND

The incidence of oesophageal adenocarcinoma has increased greatly. Barrett's oesophagus is a known risk factor.

AIMS

To identify changes in the incidence, prevalence, and outcome of Barrett's oesophagus in a defined population.

SUBJECTS

Residents of Olmsted County, Minnesota, with clinically diagnosed Barrett's oesophagus, or oesophageal or oesophagogastric junction adenocarcinoma.

METHODS

Cases were identified using the Rochester Epidemiology Project medical records linkage system. Records were reviewed with follow up to 1 January 1998.

RESULTS

The incidence of clinically diagnosed Barrett's oesophagus (>3 cm) increased 28-fold from 0.37/100 000 person years in 1965-69 to 10.5/100 000 in 1995-97. Of note, gastroscopic examinations increased 22-fold in this same time period. The prevalence of diagnosed Barrett's oesophagus increased from 22.6 (95% confidence interval (CI) 11.7-33.6) per 100 000 in 1987 to 82.6/100 000 in 1998. The prevalence of short segment Barrett's oesophagus (<3 cm) in 1998 was 33.4/ 100 000. Patients with Barrett's oesophagus had shorter than expected survival but only one patient with Barrett's oesophagus died from adenocarcinoma. Only four of 64 adenocarcinomas occurred in patients with previously known Barrett's oesophagus.

CONCLUSIONS

The incidence and prevalence of clinically diagnosed Barrett's oesophagus have increased in parallel with the increased use of endoscopy. We infer that the true population prevalence of Barrett's oesophagus has not changed greatly, although the incidence of oesophageal adenocarcinoma increased 10-fold. Many adenocarcinomas occurred in patients without a previous diagnosis of Barrett's oesophagus, suggesting that many people with this condition remain undiagnosed in the community.

The history of Barrett esophagus

The term Barrett esophagus has become well established in the medical literature to indicate columnar metaplasia of the distal esophagus associated with chronic gastroesophageal reflux disease. However, the historical events that led to the use of this term have become obscured. Here, the historical aspects of Barrett esophagus are reviewed, providing insight not only to this condition but also to the evolution of medical thought in general.

Esophageal lichen planus: the Mayo Clinic experience

Lichen planus (LP) is an inflammatory papulosquamous disease which may affect the squamous epithelium of the esophagus. We reviewed six patients with esophageal lichen planus (ELP) seen at Mayo Clinic Rochester between 1984 and 1998. The presenting symptoms were dysphagia (in all six patients) and odynophagia (two patients). Cervical esophageal strictures were seen in four patients; average number of esophageal dilatations required was 15 (range, 10-18). Esophageal biopsies demonstrated the classical histologic findings of ELP in two patients, and a lymphocytic infiltrate in the other four. Concomitant lichen planus (LP) was seen at other sites in five patients: all five had oral LP preceeded by ELP symptoms in all five; three had genital LP preceeded by ELP symptoms in all three; two had dermal LP, preceeded by ELP symptoms in one. Proton pump inhibitors were tried unsuccessfully in all patients. Four patients were started on systemic steroid medication; three had resolution of symptoms within 1 month.

Barrett's esophagus: prevalence and size of hiatal hernia

OBJECTIVE

Barrett's esophagus is caused by gastroesophageal reflux and predisposes to adenocarcinoma. Hiatal hernia may cause reflux. The prevalence and size of hernias in patients with Barrett's esophagus was investigated.

METHODS

Axial hernia length and the width of the diaphragmatic hiatus were measured prospectively at endoscopy.

RESULTS

A 2-cm or longer hernia was found in 96% of 46 patients with Barrett's esophagus, in 42% of 103 controls (p < 0.001), and in 72% of 18 patients with short segment Barrett's esophagus (p < 0.05 vs controls). A hernia was found in 71% of 31 controls with esophagitis and in 29% of 72 controls without esophagitis (p < 0.001). Of 54 controls with neither esophagitis or reflux symptoms, 20% had a hernia. Mean hernia length was 3.95 cm in Barrett's esophagus, and 2.81 cm in controls (p < 0.005). Mean hiatus width was 3.52 cm in patients with Barrett's esophagus and hernia, and 2.24 cm in controls with hernia. Hernia length was similar in patients with and without esophagitis, and in short segment Barrett's esophagus.

CONCLUSIONS

Most patients with Barrett's esophagus have hiatal hernia; their hernias are longer and the hiatal openings wider than in controls with or without esophagitis. Hiatal hernia likely contributes to the development of Barrett's esophagus.

The human high-affinity immunoglobulin G receptor activates SH2-containing inositol phosphatase (SHIP)

On cytokine-primed U937 cells, aggregation of the human high-affinity immunoglobulin receptor, FcgammaRI, initiates signal transduction cascades which lead to the release of calcium from intracellular stores and no significant calcium influx. In these cells, aggregation of FcgammaRI results in no significant increase in inositol trisphosphate production, but rather phospholipase D is activated. Here we show that, in interferon-gamma (IFN-gamma)-primed cells, the SH2 containing inositol 5' phosphatase, SHIP, is constitutively associated with the membrane fraction. Following aggregation of FcgammaRI, SHIP is rapidly and transiently tyrosine phosphorylated and becomes associated with the adapter molecule Shc. Shc also becomes tyrosine phosphorylated and translocates from the cytoplasm to the membrane fraction concomitant with the association between Shc and SHIP. Further, SHIP and Shc appear to be recruited to membrane-associated immune complexes following FcgammaRI aggregation. As no immunoreceptor inhibitory motif has been demonstrated to associate with FcgammaRI, these data suggest that SHIP may be recruited to the receptor through an SH2 domain interaction with Shc.

Videoendoscopic diagnosis of esophageal motility disorders

BACKGROUND

Esophageal motility disorders are usually diagnosed by manometry. We evaluated videoendoscopy as a diagnostic test.

METHODS

In this study, 20 patients with achalasia, 13 with scleroderma, and 33 control subjects had a standard endoscopic examination followed by protocol videotaping of swallows to observe contractions in the esophagus and in the lower esophageal sphincter. Tapes were later reviewed by 2 blinded observers who recorded their motility findings and diagnoses.

RESULTS

In the mid esophagus at 25 cm, lumen-occluding peristaltic contractions were identified in 26 of 33 control subjects versus 1 of 20 achalasia (p < 0.001) and 3 of 13 scleroderma patients (p < 0.005). As viewed in the lower esophagus, the lower esophageal sphincter opened normally in 31 of 33 control subjects versus 1 of 20 achalasia (p < 0.001). In scleroderma, the sphincter never closed in 12 of 13 patients (p < 0. 001 versus control subjects). A diagnostic sequence of sphincter opening followed by contraction in the esophageal body and subsequent sphincter closing was seen in 33 of 33 control subjects, 2 of 20 achalasia, and 1 of 13 scleroderma patients (both, p < 0. 001). The observers made the correct diagnosis in 96% of cases.

CONCLUSIONS

Achalasia and esophageal scleroderma can be identified by endoscopic observation of motility. This procedure may represent an adjunctive diagnostic test to manometry.

Management of Barrett's esophagus

In Barrett's esophagus, the squamous lining of the lower esophagus is replaced by columnar epithelium. Barrett's esophagus is associated with gastroesophageal reflux and an increased risk of the development of esophageal cancer. Endoscopy shows red columnar epithelium in the lower esophagus. Biopsy is needed to confirm intestinal metaplasia. Some cases progress from dysplasia to invasive adenocarcinoma. Medical or surgical antireflux treatment controls symptoms and esophagitis, but Barrett's esophagus remains. Patients are usually followed up by endoscopy for detection of dysplasia or early cancer. For patients with low-grade dysplasia, follow-up is adequate; however, for those with high-grade dysplasia, esophagectomy or experimental endoscopic mucosal ablation is advised.

A molecular switch changes the signalling pathway used by the Fc gamma RI antibody receptor to mobilise calcium

BACKGROUND

Leukocytes express Fc gamma receptors, which are specific for the constant region of immunoglobulin G. Aggregation of these receptors activates a repertoire of responses that can lead to targeted cell killing by antibody-directed cellular cytotoxicity. The nature of the myeloid response to Fc gamma receptor aggregation is highly variable and depends on the maturation state of the cell, but little is known about the signalling mechanisms underlying this variability.

RESULTS

We show here that differentiation of a monocytic cell line, U937, to a more macrophage phenotype resulted in an absolute and fundamental switch in the nature of the phospholipid signalling pathway recruited following Fc gamma receptor aggregation. In cytokine-primed monocytes, aggregation of the high-affinity receptor Fc gamma RI resulted in the activation of phospholipase D and sphingosine kinase, which in turn led to the transient release of stored calcium; these effects were mediated by the gamma chain, an Fc gamma RI accessory protein. In contrast, in cells differentiated to a more macrophage type, aggregation of Fc gamma RI resulted in the Fc gamma RIIa-mediated activation of phospholipase C, and the resulting calcium response was prolonged as calcium entry was stimulated.

CONCLUSIONS

The switch in Fc gamma RI signalling pathways upon monocyte differentiation is mediated by a switch in the accessory molecule recruited by Fc gamma RI, which lacks its own intrinsic signal transduction motif. As many immune receptors have separate polypeptide chains for ligand binding and signal transduction (allowing a similar switch in signalling pathways), the mechanism described here is likely to be widely used.

Critique of the National Cancer Institute of Canada's framework for cancer control

This paper offers a critique of the National Cancer Institute of Canada's (NCIC) framework for cancer control. The critique has been prepared by researchers who used the framework to review the literature in 5 substantive areas. These reviews, published in the current and previous issues of CPC, were designed to begin to outline a research agenda for the Sociobehavioural Cancer Research Network. In this paper, the authors reflect on the strengths and limitations of the framework. Perceived strengths are that the framework (a) facilitates systematic thinking about research options and priorities, (b) helps foster clear communication, (c) links science and practice, (d) may assist grant review panels to place proposed studies in context and (e) emphasizes important values. Perceived concerns include the following: (a) potential users are not familiar with the framework, (b) lack of clarity of definitions and classification criteria, (c) the utility of the framework is not immediately self-evident to potential users, (d) the framework lacks emphasis on environmental and policy interventions and (e) it is not clear how the values espoused are to be integrated with other dimensions of the framework. The concerns were seen as remediable. In short, the framework was seen to be valuable in its current form; refinement may enhance its value.

Familial aggregation of gastroesophageal reflux in patients with Barrett's esophagus and esophageal adenocarcinoma

BACKGROUND & AIMS

Barrett's esophagus and adenocarcinoma are complications of gastroesophageal reflux disease. The aim of this study was to look for evidence of a familial predisposition to reflux.

METHODS

Index patients with adenocarcinoma (n = 27), Barrett's esophagus (n = 40), and reflux esophagitis (n = 55) were recruited from tertiary care and community populations. Parents and siblings of patients (n = 243) and their spouses' relatives (n = 230) completed reflux symptom questionnaires (response rate, 86%).

RESULTS

Reflux symptoms were significantly more prevalent among parents and siblings of patients with adenocarcinoma (43% vs. 23%) and Barrett's esophagus (46% vs. 27%) than spouse control relatives. No significant difference was found for the reflux esophagitis group (33% vs. 29%). Reflux was more prevalent in siblings than spouses of patients with Barrett's esophagus (41% vs. 12%) and adenocarcinoma (40% vs. 6%), a difference that was not found with reflux esophagitis (24% vs. 32%). Reflux was associated with obesity, 41% vs. 28% in the nonobese; smoking, 45% vs. 31% in nonsmokers; and men, 39% vs. 27% in women.

CONCLUSIONS

There may be a genetic predisposition to the development of reflux in families of patients with Barrett's esophagus and esophageal adenocarcinoma. For uncomplicated reflux esophagitis, environmental factors appear more important.

Epidemiology of columnar-lined esophagus and adenocarcinoma

Barrett's esophagus is found in about 1% of the older population and in 3% to 5% of persons with gastroesophageal reflux. It is acquired more commonly by men and the prevalence increases with age. Most cases in the population remain undiagnosed. The incidence of adenocarcinoma of the esophagus and esophagogastric junction is increasing, both being related to Barrett's esophagus. Small areas of intestinal metaplasia are common but of uncertain significance.

School-based smoking control: a research agenda

Within the context of a framework for cancer control, this article reviews evidence and suggests research directions for 3 types of school-based smoking interventions: elementary school prevention, secondary school interventions and interventions linking community and school. Directions for smoking research in elementary schools include improving adoption through the provision of effectiveness criteria, tailoring interventions to schools and training. Monitoring at micro and macro levels may help planning and implementation, but clearer evidence is required of its feasibility. Fundamental research should explore new options to understand why youth do not start smoking. Smoking intervention research at the secondary school level is less well established, with only 1 effectiveness trial reported. We recommend testing models that involve youth in developing their own solutions and examining the interaction of various control measures. Sustainability issues have led researchers to embed school-based smoking interventions in community-wide activities. Intervention research of this sort still needs to determine how to apply approaches (e.g., comprehensive school health) and what the appropriate roles are (such as technical assistance) for community agencies. All research using these school-community approaches needs to include process measures to explain potential failures to obtain significant differences between components. In addition, we call for research on the training of educators and health personnel, to increase the priority given to smoking prevention and improve the implementation of existing programs. Research on policy initiatives that lead to effective training needs to be explored. Finally, we argue that application of the principles incorporated into the cancer control framework (e.g., through participatory research methods) strengthens the research process and results.

Barrett's esophagus, high-grade dysplasia, and early adenocarcinoma: a pathological study

OBJECTIVES

In Barrett's esophagus, early adenocarcinomas are often missed on endoscopic biopsy. We therefore examined the distribution and extent of dysplasia and carcinoma in the resected esophagus for comparison with the preoperative biopsy findings.

METHODS

Patients whose endoscopy showed Barrett's esophagus but no visible cancer had four-quadrant esophageal biopsies taken every 2 cm. After resection for high-grade dysplasia or early adenocarcinoma, the esophagus was mapped histologically.

RESULTS

Nineteen patients had surgery for high-grade dysplasia; two of them (10.5%) had adenocarcinoma in the resected esophagus. Eleven patients had resection after a biopsy diagnosis of adenocarcinoma or suspicion of adenocarcinoma. Esophagectomy mapping confirmed carcinoma in only five of them. Median surface areas were: total Barrett's esophagus 32 sq cm, low-grade dysplasia 13 sq cm, high-grade dysplasia 1.3 sq cm, adenocarcinoma (seven cases) 1.1 sq cm.

CONCLUSIONS

Areas of high-grade dysplasia and microscopic carcinoma in Barrett's esophagus are often small. Biopsy differentiation between these lesions is difficult. A systematic endoscopic biopsy protocol will reduce the chance of missing early malignancy in Barrett's esophagus.

Adenocarcinoma of the esophagogastric junction and Barrett's esophagus

BACKGROUND & AIMS

Barrett's esophagus is associated with adenocarcinoma of the esophagus. The aim of this study was to find the prevalence of Barrett's esophagus in patients with adenocarcinoma of the esophagogastric junction.

METHODS

Consecutive, freshly resected surgical esophagogastrectomy specimens were examined, and multiple histological sections were made around the tumor periphery. Barrett's esophagus was defined as specialized columnar epithelium above the esophagogastric junction. Tumors centered < or = 2 cm from the junction were defined as junction cancers.

RESULTS

Barrett's esophagus was found in 9 of 9 (100%) esophageal adenocarcinomas compared with 0 of 8 (0%) squamous carcinoma controls (P < 0.001). Ten of 24 (42%) junction adenocarcinomas had a Barrett's esophagus. A Barrett's esophagus was found in 8 of 12 (67%) junction cancers < or = 6 cm in length but only 2 of 12 (17%) larger tumors (P < 0.05). Barrett's esophagus was significantly associated with junction tumors < 6 cm compared with squamous carcinoma controls (P < 0.02). In 5 specimens with junction cancer, the length of Barrett's esophagus was < 3 cm, and in 5 specimens it was > or = 3 cm. Specialized epithelium was often found below the esophagogastric junction in controls.

CONCLUSIONS

Adenocarcinomas of the esophagogastric junction are associated with short and long segments of Barrett's esophagus. Larger cancers probably overgrow and conceal the underlying specialized columnar epithelium from which they arise.

Isolation and cloning of a protein-serine/threonine phosphatase from an archaeon

A divalent metal ion-stimulated protein-serine/threonine phosphatase, PP1-arch, was purified approximately 1,000-fold from the extreme acidothermophilic archaeon Sulfolobus solfataricus (ATCC 35091). Purified preparations contained 40 to 70% of total protein as PP1-arch, as determined by assay-ing sodium dodecyl sulfate-polyacrylamide gels for protein phosphatase activity. The first 25 amino acids of the protein's sequence were identified, as well as an internal sequence spanning some 20 amino acids. Using this information, we cloned the gene for PP1-arch via the application of PCR and conventional cloning techniques. The gene for PP1-arch predicted a protein of 293 amino acids that bore striking resemblance to the members of the major family of protein-serine/threonine phosphatases from members of the domain Eucarya, the PP1/2A/2B superfamily. The core of the protein, spanning residues 4 to 275, possessed 29 to 31% identity with these eucaryal protein phosphatases. Of the 42 residues found to be absolutely conserved among the known eucaryal members of the PP1/2A/2B superfamily, 33 were present in PP1-arch. If highly conservative substitutions are included, this total reached 37. The great degree of sequence conservation between molecules from two distinct phylogenetic domains implies that the members of this enzyme superfamily had evolved as specialized, dedicated protein phosphatases prior to the divergence of members of the Archaea and Eucarya from one another.