Five-year follow-up of a family-based multidisciplinary program for children with obesity

OBJECTIVE

This study aimed to determine 5-year outcomes from a 12-month, family-based, multidisciplinary lifestyle intervention program for children.

METHODS

This study was the 5-year follow-up of a randomized clinical trial comparing a low-intensity control group (home-based assessments) with a high-intensity intervention group (assessments plus weekly sessions) in New Zealand. Participants were aged 5 to 16 years with BMI ≥ 98th centile or > 91st centile with weight-related comorbidities. The primary outcome was BMI standard deviation score (BMISDS). Secondary outcomes included various health markers.

RESULTS

Of the 199 children included in the study at baseline (47% who identified as Māori, 53% who identified as female, 28% in the most deprived quintile, mean age = 10.7 years, mean BMISDS = 3.12), 86 completed a 5-year assessment (43%). BMISDS reduction at 12 months was not retained (control = 0.00 [95% CI: -0.22 to 0.21] and intervention = 0.17 [95% CI: -0.01 to 0.34]; p = 0.221) but was greater in participants aged <10 years versus >10 years at baseline (-0.15 [95% CI: -0.33 to 0.03] vs. 0.21 [95% CI: 0.03 to 0.40]; p = 0.008). BMISDS trajectory favored participants with high attendance (p = 0.013). There were persistent improvements in water intake and health-related quality of life in both groups as well as reduced sweet drink intake in the intervention group.

CONCLUSIONS

This intervention, with high engagement from those most affected by obesity, did not achieve long-term efficacy of the primary outcome. Attendance and age remain important considerations for future interventions to achieve long-term BMISDS reduction.

A new approach to assessment of the left ventricle

Cardiac motion is a continuous process; however most measurements to assess cardiac function are taken at brief moments in the cardiac cycle. Using functional data analysis, repeated measurements of left ventricular volume recorded at each frame of a continuous image measured with cardiac ultrasound (echocardiography) were turned into a function of volume over time. The first derivative of the displacement of volume with respect to time is velocity; the second derivative is acceleration. Plotting volume, velocity, and acceleration against each other in a 3-dimensional plot results in a closed loop. The area within the loop is defined by the kinematics of volume change and so may represent ventricular function.

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We have developed an approach to analyzing images of the left ventricle that incorporates information from throughout the cardiac cycle.

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Comparing systolic and diastolic areas within a loop defined by volume, velocity, and acceleration of left ventricular volume highlights imbalances in the kinematics of the two phases, potentially indicating early sub-clinical disease.

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Substantially more information about left ventricular function may be derived from a non-invasive clinically available tool such as echocardiography.

Food Intolerance: Associations with the rs12212067 Polymorphism of FOXO3 in Crohn's Disease Patients in New Zealand

BACKGROUND

Diet is known to play a major role in Crohn's disease (CD). It has also been reported that the minor G allele from the rs12212067 polymorphism (T>G) in FOXO3 is associated with milder CD. The aim of this study was to investigate the association between the rs12212067 polymorphism and food intolerances for a total of 253 foods.

METHODS

Tolerances and intolerances were recorded on a self-reported dietary questionnaire. Each food was scored on a 5-point ordinal scale: beneficial effects as '+ +' or '+', adverse effects as '- -' or '-', and 'makes no difference' as '='. Dietary and genotype data were available for a total of 283 CD patients.

RESULTS

We identified 17 foods with beneficial effects in our study which were significantly associated with the G allele of the FOXO3 rs12212067 polymorphism. Of these, sweet potatoes had the highest reported frequency of beneficial responses. We also identified 4 foods with detrimental effects in more than 25% of our study population. These were mustard, wasabi, and raw and cooked tomatoes, which again were significantly associated with the G allele in FOXO3.

CONCLUSIONS

There was strong evidence that adverse effects of mustard, wasabi, and raw and cooked tomatoes were significantly associated with the G allele of FOXO3 and that these foods should be avoided by people carrying this allele.

The development and feasibility of a composite score of echocardiographic indices that may stratify outcome in patients with diabetes mellitus

BACKGROUND

Early detection of changes in cardiac structure and function associated with type 2 diabetes (T2DM) is important. However when multiple abnormalities are present, combining individual measurements can be subjective. This study sought to create a simple echo score that summarises measurements that may detect early and prognostically important changes in cardiac function.

METHODS

Standard echocardiography was performed on 849 people with T2DM (median age 65years, 40% female, median duration of diabetes 5.5years). Principal components analysis was performed on measurements of LV mass, LA volume, E:e', and s', to create an objective summary score. The score was included in two Cox proportional hazard models adjusted for CV risk factors: one estimated the development of heart failure (HF) and the second estimated any CV event.

RESULTS

The first two principal components represented 75% of the variation between the four echo measurements. A continuous score that represents the residual difference between these two components was derived that only requires measurement of medial E:e' and s'. The score was significantly associated with the development of HF within four years (hazard ratio 1.34; 95% CI 1.15, 1.56).

CONCLUSIONS

We have developed a simple, objective score that enhances the use of echocardiography in the detection of sub-clinical cardiac disease in people with T2DM. Initial findings suggest that it may help identify those at increased risk of developing HF within four years.

Effects of supplementation with selenium, as selenized yeast, in a healthy male population from New Zealand

Selenium (Se) supplementation was tested in a group of healthy men from Auckland, New Zealnd with selenized yeast (Selplex, 200 μg/day) as the supplementation mode. A set of biomarkers, including DNA damage levels and seleno-antioxidant enzyme levels, were evaluated at pre- and postsupplementation time points. Supplementation produced significant increases in serum Se levels, red blood cell (RBC) thioredoxin reductase (TR) activity and peroxide-induced DNA damage, when the mean baseline serum Se level was 110 ng/ml. Those with higher baseline serum Se levels gained less serum Se and showed a significant reduction of RBC glutathione peroxidase (GPx) activity by supplementation. The optimum benefits of supplementation on DNA stability are observed when the serum Se level reaches between >120 and <160 ng/ml. However, the most significant observation was that those with highest baseline DNA damage benefit the most from Se supplementation, whereas those having lower baseline DNA damage are disadvantaged. A dose of 200 μg/day selenized yeast was also shown to be a safer supplementation option compared to a similar dose of selenomethionine (SeMet). This study highlights the requirement for prestratification of a population by standing serum Se level and baseline DNA damage level, before any Se supplementation is carried out.

Brassicaceae: nutrient analysis and investigation of tolerability in people with Crohn’s disease in a New Zealand study

Background: Nutrition is an important environmental factor influencing symptoms of Crohn’s disease, one of the two main expressions of inflammatory bowel disease. Varieties of Brassicaceae supply valuable nutrients. They are often avoided by people with Crohn’s disease because of the adverse effects they are perceived to have on symptoms. The purpose of this study was to review the nutritional content of commonly eaten forms of Brassicaceae and identify from selected Brassicaceae those that exacerbate, ameliorate or make no difference to the symptoms of people with Crohn’s Disease. Methods: In this study commonly eaten Brassicaceae were identified and analysed for major nutrients, vitamins, minerals, phytochemicals and FODMAPs. An investigation on the tolerability of ten forms of Brassicaceae on people with Crohn’s disease was also conducted. This was based on the responses of adult subjects in the ‘Genes and Diet in Inflammatory Bowel Disease Study’ based in Auckland, New Zealand. Results: The nutrient analysis of the Brassicaceae showed their important contribution of fibre, vitamins, minerals, and phytochemicals, especially glucosinolates. Our study revealed that over 70% of respondents found that the consumption of broccoli, Chinese greens and rocket (arugula) made no difference to their Crohn’s disease (p=0.0001).Conclusions: Brassicaceae contain key nutrients which contribute significantly to a person’s health through their fibre, vitamin, mineral and phytochemical content. Many people with Crohn’s Disease can tolerate different forms of Brassicaceae. By identifying the particular varieties that can be consumed by people with Crohn’s disease and encouraging them to eat them, their nutrition, immune status and anti-inflammatory and anti-cancer factors will be enhanced.Key words: Brassicaceae: Key nutrients: Tolerability: Crohn’s Disease

Serum selenium and single-nucleotide polymorphisms in genes for selenoproteins: relationship to markers of oxidative stress in men from Auckland, New Zealand

There is controversy as to the recommended daily intake of selenium (Se), and whether current New Zealand diets are adequate in this nutrient. Various functional single-nucleotide polymorphisms (SNPs) polymorphisms may affect the efficacy of Se utilisation. These include the glutathione peroxidases GPx1 rs1050450, GPx4 rs713041, as well as selenoproteins SEPP1 rs3877899, SEL15 rs5845, SELS rs28665122 and SELS rs4965373. This cross-sectional study measured serum Se levels of 503 healthy Caucasian men in Auckland, New Zealand, between ages 20-81. The Se distribution was compared with activities of the antioxidant enzymes glutathione peroxidase and thioredoxin reductase, and DNA damage as measured by the single cell gel electrophoresis assay, both without and with a peroxide-induced oxidative challenge. Serum Se was measured using inductively coupled plasma-dynamic reaction cell-mass spectrometry, while selenoprotein SNPs were estimated using TaqMan(®) SNP genotyping assays. While antioxidant enzyme activities and DNA damage recorded after a peroxide challenge increased with increasing serum selenium, the inherent DNA damage levels in leukocytes showed no statistically significant relationship with serum selenium. However, these relationships and dietary Se requirements at the individual level were modified by several different SNPs in genes for selenoproteins. The GPx1 rs1050450 C allele was significantly associated with GPx activity. Significant correlations between serum Se level and GPX activity were seen with all genotypes except for homozygous minor allele carriers, while the GPx1 rs1050450 CT genotype showed the highest correlation. Several genotypes showed significant correlations between serum Se and TR activity with SEPP1 rs3877899 GG genotype showing the highest correlation. A significant decreasing trend in DNA damage with increasing serum Se was seen among GPx1 rs1050450 CC and GPx4 rs713041 TT genotype carriers up to a serum Se level of 116 and 149 ng/ml, respectively. In the absence of this genetic information, we would recommend a serum Se concentration in the region of 100-150 ng/ml as providing a useful compromise.

Role of echocardiographic left ventricular mass and carotid intima-media thickness in the cardiovascular risk assessment of asymptomatic patients with type 2 diabetes mellitus

BACKGROUND

Standard cardiovascular (CV) risk assessment may underestimate risk in people with type 2 diabetes mellitus (T2DM). Cardiac and vascular imaging to detect subclinical disease may augment risk prediction. This study investigated the association between CV risk, left ventricular hypertrophy (LVH) and carotid intima-media thickness (CIMT) in patients with T2DM free of CV symptoms.

METHODS

People with T2DM without known CV disease were recruited from general practice. The 5-year risk of CV events was calculated using an adjusted Framingham equation and the prevalence of LVH and abnormal CIMT across bands of CV risk assessed. In those at intermediate risk, the number needed to scan (NNS) to reclassify one person to high risk was calculated across the group and compared in those above and below 55 years. The association between LV mass and CIMT was also assessed.

RESULTS

Mean age 57 years (SD11), 51% female. Median 5-year CV risk 14.3% (interquartile range 10.3, 19.5), 51% had LVH (American Society of Echocardiography criteria) and 31% an abnormal CIMT (age and sex criteria). In the 52% at intermediate risk, 37% had LVH and 36% an abnormal CIMT. The NNS was 1.7 using both imaging techniques, 2.7 using cardiac imaging alone or 2.8 using vascular imaging alone. Almost twice as many people >55 years had an abnormal CIMT than those <55 years.

CONCLUSIONS

Cardiac and vascular imaging to detect subclinical disease can be used to augment prediction of CV risk in people with T2DM at intermediate risk. The value of reclassifying risk is as yet unproven and requires outcome data from intervention studies.

Dietary factors in chronic inflammation: food tolerances and intolerances of a New Zealand Caucasian Crohn's disease population

Diet is known to play a major role in the symptoms of the inflammatory bowel disease, Crohn's disease (CD). Although no single diet is appropriate to all individuals, most CD patients are aware of foods that provide adverse or beneficial effects. This study seeks to categorise foods in relation to their effects on symptoms of CD, in a New Zealand Caucasian population. Four hundred and forty-six subjects from two different centres in New Zealand were recruited into the study. An extensive dietary questionnaire (257 food items in 15 groups) recorded self-reported dietary tolerances and intolerances. Across each of the food groups, there were statistically significant differences among responses to foods. A two-dimensional graphical summary enabled stratification of foods according to the probability that they will be either beneficial or detrimental. A small number of foods are frequently considered to be beneficial, including white fish, salmon and tuna, gluten-free products, oatmeal, bananas, boiled potatoes, sweet potatoes (kumara), pumpkin, soya milk, goat's milk and yoghurt. Foods that are typically considered detrimental include grapefruit, chilli or chilli sauce, corn and corn products, peanuts, cream, salami, curried foods, cola drinks, high energy drinks, beer, and red wine. For a number of the food items, the same item that was beneficial for one group of subjects was detrimental to others; in particular soya milk, goat's milk, yoghurt, oatmeal, kiwifruit, prunes, apple, broccoli, cauliflower, linseed, pumpkin seed, sunflower seed, ginger and ginger products, beef, lamb, liver, and oily fish. It was not possible to identify a specific group of food items that should be avoided by all CD patients. The wide range of detrimental items suggests that dietary maintenance of remission is likely to be difficult, and to exclude a substantial number of foods. Personalised diets may be especially important to these individuals.

The sensitivity of the Bayesian HPD method to the choice of prior

Statistical sampling error is present in every statistical calculations using DNA because all such statistics rely on a sample (database) of individuals, which is used to estimate the population frequencies of alleles. Curran et al.gave a method for estimating the sampling error of the statistics based on the region of the highest density of the Bayesian posterior (HPD). The Bayesian HPD method relies on the assumption of a prior distribution for the population allele frequencies as well as Monte Carlo simulation. In this paper we answer three pivotal questions. Firstly we address the question of how many Monte Carlo iterations are required to get sufficient accuracy in our estimates of sampling error. Secondly, we address the question of the appropriate choice of the prior distribution for the population allele frequencies. Thirdly, we demonstrate the flexibility of the Bayesian HPD over other methods.

An extended likelihood ratio framework for interpreting evidence

This paper reviews some current methods, the likelihood ratio-based approach and the full Bayesian approach for the interpretation of evidence and discusses previously identified shortcomings in them. It suggests an approach based on a compromise--based on an extended likelihood ratio--that may combine the merits of logic without overstepping acceptable bounds for the forensic scientist in the presentation of evidence. The approach is exposed formally and takes advantage of inferential networks called Bayesian networks.

Relatedness and DNA: are we taking it seriously enough?

In forensic DNA testimony most DNA laboratories report the match probability for an unrelated person from some relevant population. These laboratories typically make available the match probability for relatives when requested. This practice has served well for many years. However, as the discrimination power of our multiplexes has increased the estimated match probabilities for both related and unrelated people have become markedly smaller. Associated with this general reduction in match probabilities have been the observations that the relative balance between the match probabilities of the many unrelated people and the few relatives of a suspect has changed. We suggest that we should now report routinely the match probability for a sibling whenever the suspect has a non-excluded sibling.

A model for estimating the number of glass fragments transferred when breaking a pane: experiments with firearms and hammer

Numerous publications have shown the importance of transfer in the interpretation of glass evidence. As this phenomenon is also highly variable, it was decided to test the hypothesis that there exists a means to predict the number of fragments recovered at time t = 0. Panes of float glass-of different types and thickness-were broken using either a firearm or a hammer. It was decided to choose a firearm as the main breaking device, as it allowed not only to have more reproducible conditions but also to acquire knowledge in a field where little has been published. Despite the inherent variation in the breaking process, the results show that using a statistical model it is possible to predict the number of fragments transferred onto a garment from the number of fragments transferred to the ground. This research also indicates the size and number of particles transferred onto a person, when breaking window panes of different types (float, laminated or toughened) with different breaking procedures.

Evidence in support of self-declaration as a sampling method for the formation of sub-population DNA databases

Well constructed sub-population databases are fundamental to the application of DNA-based forensic statistics. The size of such databases can affect the ability to examine adequately statistical or population genetic features, and the integrity of both the DNA profile and associated ethnicity information is also of importance. Use of short tandem repeat (STR) DNA profiling technology and the thoughtful construction of the governing legislation has seen large databases of DNA profiles collated for the four major sub-populations of New Zealand. Examination of the data illustrates the suitability of self-declaration as a means of categorizing samples on the basis of ethnicity.

What is the magnitude of the subpopulation effect?

The effect of population subdivision on estimated match probabilities has been raised [Nature 339 (1989) 501; Am. J. Hum. Genet. 48 (1991) 819; Science 254 (1991) 1921]. Previous work [J. Forensic Sci. 39 (1994) 319; J. Forensic Sci. 39 (1994) 988; Am. J. Hum. Genet. 55 (1994) 533] has compared product rule estimates from differing databases and found that the "subpopulation" error may be of the order of a factor of 10. This approach compares an estimate with an estimate. This paper uses simulation to extend these studies by allowing a comparison to a 'true match probability' and supports the conclusion that subpopulation effects are mild. In addition the performance of recommendations 4.1 and 4.2 of NRC II [National Research Council and C.O.D.F. Science, The Evaluation of Forensic DNA Evidence, National Academy Press, Washington, DC, 1996].

The two trace transfer problem re-examined

The classical two trace transfer problem initially discussed by Evett is reconsidered [Evett IW. On Meaningful Questions: A Two-Trace Transfer Problem. Journal of the Forensic Science Society 1987; 27: 375-381]. In this problem we consider the situation where there are two stains of differing types at a crime scene. Evett considered the situation where both are known to be relevant to the offence. It was further assumed that there were exactly two offenders. Reanalysis of this problem suggests that the key consideration is the conditioning on there being exactly two offenders, not that there were two stains. The treatment here leads easily to a generalisation in which stains have differing relevance and there are k offenders.

Effects of population structure and admixture on exact tests for association between Loci

The probability of multilocus genotype counts conditional on allelic counts and on allelic independence provides a test statistic for independence within and between loci. As the number of loci increases and each sampled genotype becomes unique, the conditional probability becomes a function of total heterozygosity. In that case, it does not address between-locus dependence directly but only indirectly through detection of the Wahlund effect. Moreover, the test will reject the hypothesis of allelic independence only for small values of heterozygosity. Low heterozygosity is expected for population subdivision but not for population admixture. The test may therefore be inappropriate for admixed populations. If individuals with parents in two different populations are always considered to belong to one of the populations, then heterozygosity is increased in that population and the exact test should not be used for sparse data sets from that population. If such a case is suspected, then alternative testing strategies are suggested.

A comparison of adjustment methods to test the robustness of an STR DNA database comprised of 24 European populations

An aim of the European Network of Forensic Science Institutes (ENFSI) is to produce a DNA database of second generation multiplex (SGM) STR profiles that is representative of the resident cosmopolitan populations. To achieve this, data were collected from 24 different populations. All of the data were combined to form one database of 5700 profiles from which allele proportions were calculated. The robustness of this combined European database was tested by estimating parameter d for every DNA profile, where d=log(10)(Pm(c)/Pm(E)) Pm(c) is the match probability of the profile calculated from its cognate database and Pm(E) is the match probability of the combined European database. Overall there was a small tendency for Pm(c)>Pm(E) primarily because of sampling bias. This bias was removed by the simple expediency of applying an adjustment factor to the calculation of Pm(E). These were selected from the Balding size bias correction, the Balding and Nichols Fst correction, a minimum allele proportion (between 0.01 and 0.02), an upper bound of a 95% confidence interval (CI) and a lower bound on the genotype match probability. It was demonstrated that a single European database is a feasible proposition. A combination of different adjustment methods can be used to ensure that the result is conservative relative to the cognate database, and their effect measured by parameter d.

Does capture-recapture analysis provide more reliable estimates of the incidence and prevalence of leg ulcers in the community?

OBJECTIVE

To determine whether capture-recapture analysis provides more reliable estimates of the cumulative incidence and prevalence of leg ulcers in Auckland, New Zealand.

METHODS

A population-based, cross-sectional study was conducted in the Central and North Auckland health districts of New Zealand in 1998. Cases were identified through health professional referral and by self-notification. All ages and ulcer types were investigated. Both traditional and capture-recapture methods of analysis were used to estimate the cumulative incidence and prevalence of leg ulcers in the study population.

RESULTS

Four hundred and twenty-six people with current leg ulcers were identified during the 12-month study period. Using traditional methods of analysis, the annual cumulative incidence rate of leg ulcers in Auckland was 32 per 100,000, with a point prevalence of 39 per 100,000 and a period prevalence of 79 per 100,000 per year. Results from capture-recapture analysis, however, suggest an annual cumulative incidence rate of 252 per 100,000, with a point prevalence of 248 per 100,000 and a period prevalence of 530 per 100,000 per year.

CONCLUSIONS

The traditional method of calculating cumulative incidence and prevalence clearly under-estimates the frequency of leg ulcers in the Auckland region. Capture-recapture analysis provides a more reliable estimate of disease frequency, since cases that remain unidentified in the population are considered.

Logical implications of applying the principles of population genetics to the interpretation of DNA profiling evidence

There have been several efforts to codify the approach to interpreting DNA evidence [National Research Council, The Evaluation of Forensic DNA Evidence, National Academy Press, Washington, DC, 1996; I.W. Evett, B.S. Weir, Interpreting DNA Evidence: Statistical Genetics for Forensic Scientists Sinauer, Sunderland, MA, 1998]. Despite these efforts there are still aspects of ad hoc decision making in modern DNA interpretation. This article discusses some of the remaining areas of concern in this respect. Because of the immense discriminating power of DNA evidence it is unlikely that these concerns would contribute to a miscarriage of justice. They are more likely to lead to lengthy and wasteful debate in court, and to potential appeals. We advocate a previously developed approach to DNA evidence [Sci. Justice 39 (4) (1999) 257; B.S. Weir, in: D.J. Balding, C. Cannings, M. Bishop (Eds.), Handbook of Statistical Genetics, Wiley Series in Probability and Statistics, Wiley, New York, ISBN: 0-471-86094-8, 2001; J. R. Stat. Soc. A 158 (1) (1995) 21] that would give a more solid logical foundation and hopefully lead to sounder and less debatable testimony.

Limitation of thrombin generation, platelet activation, and inflammation by elimination of cardiotomy suction in patients undergoing coronary artery bypass grafting treated with heparin-bonded circuits

OBJECTIVE

Reports evaluating the efficacy of heparin-bonded circuits to blunt inflammation, platelet dysfunction, and thrombin generation in response to cardiopulmonary bypass have varied. We hypothesized that this variability may in part be related to the use of cardiotomy suction, which has been demonstrated to reintroduce procoagulant and proinflammatory factors into the systemic circulation during cardiopulmonary bypass. A prospective, randomized study was undertaken to evaluate the specific effects of cardiotomy suction.

METHODS

Thirty-six patients undergoing first-time, nonemergency coronary artery bypass grafting with cardiopulmonary bypass were randomly assigned to one of three treatment groups: group I, non-heparin-bonded circuits with the use of cardiotomy suction (n = 12); group II, Duraflo II (BCR-3500; Jostra Bentley Corp, Irvine, Calif) heparin-bonded circuits with cardiotomy suction (n = 12); and group III, Duraflo II heparin-bonded circuits without cardiotomy suction (n = 12). Thrombin generation, neutrophil activation (polymorphonuclear elastase), platelet activation (beta-thromboglobulin), and neuronal injury (neuron-specific enolase) were analyzed by enzyme-linked immunosorbent assays after cardiopulmonary bypass and compared with prebypass levels. Results are presented as mean +/- SEM.

RESULTS

Prebypass levels of all markers were similar among treatment groups. However, postbypass levels were significantly and consistently highest in group I relative to groups II and III. Thrombin generation levels were 5.0 +/- 0.9 nmol/L in group I, 3.0 +/- 0.6 nmol/L in group II, and 1.5 +/- 0.1 nmol/L in group III (P <.05 vs group II and P <.001 vs group I). Polymorphonuclear elastase levels were 307 +/- 64 microg/L in group I, 128 +/- 24 microg/L in group II (P <.05 vs group I), and 75 +/- 14 microg/L in group III (P <.001 vs group I). beta-Thromboglobulin levels were 2692 +/- 401 IU/mL in group I, 912 +/- 99 IU/mL in group II (P =.001 vs group I), and 646 +/- 133 IU/mL in group III (P =.001 vs group I). Neuron-specific enolase levels were 9.8 +/- 0.9 ng/mL in group I, 10.5 +/- 1.6 ng/mL in group II, and 4.2 +/- 0.5 ng/mL in group III (P =.001 vs groups I and II).

CONCLUSIONS

Use of cardiotomy suction resulted in significant increases in thrombin, neutrophil, and platelet activation, as well as the release of neuron-specific enolase, after cardiopulmonary bypass. Limiting increases in these markers would be best accomplished by eliminating cardiotomy suction and routinely using heparin-bonded circuits whenever possible.

Assessing uncertainty in DNA evidence caused by sampling effects

Sampling error estimation in forensic DNA testimony was discussed. Is an estimate necessary and how should it be made? The authors find that all modern methods have areas of strength and weakness. The assessment of which is the 'best' is subjective and depends on the performance of the method, the type of problem (criminal work or paternity), the database size and availability of computing software and support. The authors preferred the highest posterior density approach for performance, however the other methods all have areas where their performance is adequate. For single-contributor stains normal approximation methods are suitable, also the bootstrap and the highest posterior density method. For multiple-contributor stains or other complex situations the match probability expressions become quite complex and it may not be possible to derive the necessary variance expressions. The highest posterior density or the bootstrap provide a better general method, with non-zero theta. The size-bias correction and the factor of 10 approaches may be considered acceptable by many forensic scientists as long as their limitations are understood.

Relationships within the Proteobacteria of plant pathogenic Acidovorax species and subspecies, Burkholderia species, and Herbaspirillum rubrisubalbicans by sequence analysis of 16S rDNA, numerical analysis and determinative tests

Sequence data for 16S rDNA of the type strains of Acidovorax avenae subsp. avenae, A. avenae subsp. cattleyae, A. avenae subsp. citrulli, A. konjaci and Herbaspirillum rubrisubalbicans were compared with GenBank library accessions of Burkholderia spp., Comamonas sp., Ralstonia solanacearum and Variovorax sp. Maximum Parsimony analysis produced two clusters: 1. Acidovorax spp., Comamonas sp., and Variovorax sp. (all in the Comamonadaceae), and 2. Burkholderia spp., Ralstonia solanacearum, and Herbaspirillum rubrisubalbicans. Maximum Likelihood analysis produced only one cluster (of the Comamonadaceae). Using nutritional and laboratory tests, all Acidovorax spp., Burkholderia spp., and Herbaspirillum rubrisubalbicans were discriminated in distinct clusters at the species level, and could be identified by selected determinative tests. There were no phenotypic tests constituted as a circumscription of the genera and which permitted the allocation of strains to genera. Strain identification as species allowed allocation to genera only by inference. The nomenclatural implications of these data are discussed.

Glass on clothing and shoes of members of the general population and people suspected of breaking crimes

The outer clothing and footwear of 122 people attending a university gymnasium and a private gymnasium were searched for fragments of glass. Both the surfaces and the pockets of the clothing and the uppers and soles of the footwear were searched. New Zealand forensic glass cases have been reviewed to determine the amount of non-matching glass present on the clothing of people who are suspected of breaking crimes. Data from 114 suspects who had no matching glass on their clothing and shoes were accumulated. Statistical modelling techniques have been applied to the data collected.

Interpreting DNA mixtures in structured populations

DNA profiles from multiple-contributor samples are interpreted by comparing the probabilities of the profiles under alternative propositions. The propositions may specify some known contributors to the sample and may also specify a number of unknown contributors. The probability of the alleles carried by the set of people, known or unknown, depends on the allelic frequencies and also upon any relationships among the people. Membership of the same subpopulation implies a relationship from a shared evolutionary history, and this effect has been incorporated into the probabilities. This acknowledgment of the effects of population structure requires account to be taken of all people in a subpopulation who are typed, whether or not they contributed to the sample.

Sampling in forensic comparison problems

When someone breaks glass a number of tiny fragments may be transferred to that person. If the glass is broken in the commission of a crime then these fragments may be used as evidence. If a large number of fragments are recovered from the suspect, then it may be more efficient for the forensic scientist to examine a subset of these fragments. Such sampling incurs information loss. This paper will derive an expression that allows a partial quantification of this loss. The loss of such information due to the examination of a subset of recovered material arises with many forms of evidence.

Combining a continuous Bayesian approach with grouping information

When someone breaks glass a number of tiny fragments may be transferred to that person. If the glass is broken in the commission of a crime then these fragments may be used as evidence. A Bayesian interpretation of this evidence relies on, among other things, the forensic scientist's ability to assess the likelihood that the glass recovered from the suspect may have come from more than one source. This paper will examine the effect of including this information in the interpretation. We envisage working towards a system whereby the information loss that occurs during the normal casework activities of sample selection and glass fragment grouping is quantified.

Adsorption of a hydrophobic mutagen to cereal brans and cereal bran dietary fibres

The abilities of brans from the cereals barley, oats, maize, rice, and wheat to adsorb in vitro the hydrophobic, environmental mutagen 1,8-dinitropyrene (DNP) were investigated using a mutagenicity assay. These brans were obtained from known cultivars using defined milling conditions and were chemically characterised. The abilities of total and insoluble dietary fibre preparations obtained from these brans to adsorb DNP were also investigated. The predicted weight of each bran required to adsorb 50% of the added DNP was used to compare the adsorptive abilities of the different brans. The brans were ranked in the order (most effective to least effective): rice, wheat, maize, barley, and oats. The adsorptive abilities of the dietary fibre preparations were not significantly different from the bran from which they were prepared. However, if the dietary fibres (cell walls) were the only components adsorbing the DNP, we would have expected the dietary fibre preparations to have adsorbed more DNP than the equivalent unextracted bran. This suggests that other components, probably starch, also adsorb DNP in the unextracted brans. It is not known why brans from different cereal species differ in adsorptive ability but the lignified cell walls in wheat bran may be important in conferring good adsorptive properties to this bran. The possible relationship between adsorptive ability and ability of the bran from a particular species to protect against colorectal cancer is discussed.

Assessing transfer probabilities in a Bayesian interpretation of forensic glass evidence

When someone breaks glass a number of tiny fragments may be transferred to that person. If the glass is broken in the commission of a crime then these fragments may be used as evidence. A Bayesian interpretation of this evidence relies on the forensic scientist's ability to assess the probability of transfer. This paper examines the problem of assessing this probability and suggests some solutions.

Interpreting DNA mixtures

The interpretation of mixed DNA stains is explained in the context of likelihood ratios. The probabilities for the mixed-stain profile are evaluated under alternative explanations that specify the numbers of contributors and the profiles of any known contributors. Interpretations based simply on the frequencies with which random members of a population would not be excluded from a mixed-stain profile do not make use of all the information, and may overstate the strength of the evidence against included people. The effects of the numbers of contributors depends on whether all the alleles at a locus are present in the mixed stain. A general equation is given to allow likelihood ratios to be calculated, and includes the "2p" modification suggested by the 1996 NRC report. This modification is not always conservative. A computer program to perform calculations is available.

The adsorption of heterocyclic aromatic amines by model dietary fibres with contrasting compositions

It is often recommended that consumption of dietary fibre should in increased to protect against colorectal cancer. However, although more than 95% of dietary fibre is contributed by whole plant cell walls, very little experimental work has been done using whole plant cell walls. These may protect by adsorbing carcinogens, thus lowering their effective concentration in the alimentary tract, and by carrying the carcinogens out of the body in the faeces. However, plant cell walls vary widely in their composition and physical properties, and not all cell walls will necessarily have protective properties. We therefore isolated 4 plant cell-wall preparations with contrasting compositions as models of the types of cell walls that occur in the diet. We investigated the abilities of these preparations to adsorb in vitro 6 heterocyclic aromatic amines (HAAs). HAAs occur in the human diet and several are colon carcinogens, at least in rats. We found that the ability of the HAAs to adsorb to the plant cell walls increased with increasing hydrophobicity of the HAA, measured as the calculated logarithm of the partition coefficient between 1-octanol and water (C logP). A cell-wall preparation containing mainly the walls of parenchyma cells (the most common cell type in food plants) had only poor adsorptive ability. A cell-wall preparation from commercial cork had the best adsorptive ability. This preparation was the most hydrophobic of those examined because the cell walls contained the polymer, suberin, together with associated waxes. The preparation modelled suberized cell walls which occur in the diet, for example in potato skins. The other two cell-wall preparations contained another hydrophobic polymer, lignin, and had intermediate adsorptive abilities which were not significantly different from one another. These preparations modelled lignified cell walls which occur in the diet, for example in wheat bran. Our results indicate that suberized and lignified cell walls may be important in protecting against colorectal cancer.

The effects of a soluble-fibre polysaccharide on the adsorption of carcinogens to insoluble dietary fibres

Epidemiology and animal experiments indicate that dietary fibres protect against the development of colorectal cancer. However, insoluble dietary fibres appear to be more effective than soluble dietary fibres and one mechanism by which they may protect is by adsorbing dietary carcinogens. We found previously that the ability of a carcinogen to adsorb in vitro to alpha-cellulose (a model insoluble dietary fibre) was strongly related to the hydrophobicity of the carcinogen, measured as the calculated logarithm of the partition coefficient between 1-octanol and water (C log P). Furthermore, soluble dietary fibres (soluble-fibre polysaccharides), including gum arabic, reduced the adsorption of the hydrophobic carcinogen, DNP, to alpha-cellulose. In the present study we tested the ability of gum arabic to reduce the adsorption in vitro of the carcinogens BaP (C log P = 6.124), DNP (C log P = 4.384), and the heterocyclic amines, Trp-P-1 (C log P = 3.230) and MeIQx (C log P = 1.078). Gum arabic reduced the adsorption to alpha-cellulose of BaP and DNP, but not the adsorption of Trp-P-1 or MeIQx. Gum arabic also reduced the adsorption of BaP to an insoluble, dietary-fibre preparation from commercial cork which contains the hydrophobic component, suberin, but did not affect the adsorption of DNP, Trp-P-1 or MeIQx. It also did not affect the adsorption of DNP to an insoluble, dietary-fibre preparation from wheat straw, which contains the hydrophobic component, lignin. The results are discussed in terms of hydrophobic interactions between carcinogens and insoluble dietary fibres. In vivo, it is likely that soluble dietary fibres reduce the adsorption of only highly hydrophobic carcinogens to some insoluble dietary fibres.

Distribution of HLA DQA.1 alleles in New Zealand Caucasian, Maori and Pacific Islander populations. Comparison with other population studies

Allele and genotype frequencies for the HLA DQA.1 locus were determined for 127 unrelated Caucasians, 177 unrelated Maori and 98 unrelated Pacific Islanders from the New Zealand population. DNA from blood cells was analysed by polymerase chain reaction amplification of DNA followed by hybridization to allele specific oligonucleotide probes in a reverse dot-blot test. Allele frequencies at the HLA DQA.1 locus for New Zealand Caucasians, Maori and Pacific Islanders were compared with published data for other populations. The distribution of HLA DQA.1 genotype frequencies did not deviate from Hardy Weinberg expectations for the Caucasian and Maori populations. The power of discrimination was 0.93 for Caucasians and 0.86 for Maori. The total Pacific Islander population tested was analysed as was data obtained from Western Polynesians contained within that larger group. Both the total Pacific Islander group analysed, and the Western Polynesians contained within that larger group, failed Hardy Weinberg expectations for the distribution of HLA DQA.1 genotypes. This significant deviation was due to excess homozygotes. The power of discrimination for the total Pacific Islander group and for Western Polynesians was 0.86 and 0.85 respectively. Comparison of Caucasian population studies from New Zealand, the United Kingdom, South Australia, Norway, the United States and Sweden showed these populations have similar HLA DQA.1 allele frequency distributions. Maori and Pacific Islanders have HLA DQA.1 allele frequency distributions that are more similar to each other than any of the other populations studied.

Evaluation of determinative tests for pathovars of Pseudomonas syringae van Hall 1902

The utility of 36 presumptive determinative tests for 32 pathovars of Pseudomonas syringae was investigated. A total of 395 strains was examined. Most strains of 12 of these pathovars (Ps. syringae pv. cannabina, Ps. syr. delphinii, Ps. syr. glycinea, Ps. syr. helianthi, Ps. syr. lachrymans, Ps. syr. mori, Ps. syr. morsprunorum, Ps. syr. phaseolicola, Ps. syr. 'porri', Ps. syr. papulans, Ps. syr. savastanoi and Ps. syr. tabaci) formed clusters when test data were compared by centroid analysis. Pseudomonas syr. syringae, Ps. syr. aptata, Ps. syr. atrofaciens, Ps. syr. dysoxyli and Ps. syr. japonica formed a single cluster, indicating their possible synonymy. Strains of Ps. syr. antirrhini and Ps. syr. tomato were indistinguishable, as were those of Ps. syr. garcae and Ps. syr. oryzae. Strains of Ps. syr. berberidis, Ps. syr. coronafaciens, Ps. syr. eriobotryae, Ps. syr. maculicola, Ps. syr. passiflorae, Ps. syr. pisi and Ps. syr. striafaciens and Ps. syr. tagetis did not form distinguishable clusters. The tests which reliably differentiated pathovars are recorded in a determinative scheme.

The effects of soluble-fiber polysaccharides on the adsorption of a hydrophobic carcinogen to an insoluble dietary fiber

Dietary fiber is believed to decrease the incidence of colorectal cancer, but not all types of fiber are equally protective. Dietary fibers may be divided broadly into insoluble and soluble fibers, and there is evidence from animal experiments that the latter not only fails to protect against colorectal cancer but may enhance its development. Adsorption of carcinogens to insoluble dietary fiber in the intestinal tract is one of the mechanisms by which dietary fiber is believed to protect against colorectal cancer. In previous in vitro experiments, we showed that the hydrophobic carcinogen 1,8-dinitropyrene (DNP) adsorbs to insoluble plant cell wall components (insoluble dietary fibers). Soluble polysaccharides (pectic polysaccharides) extracted from the walls of parenchyma cells of dicotyledonous plants were found to maintain DNP in aqueous solutions and decrease its adsorption to insoluble wall components. In the present study, we examined a commercial preparation of pectin and seven other soluble-fiber polysaccharides with diverse structures for their effects on the distribution of DNP. Many of these are used as emulsifiers and stabilizers in the food industry. They all maintained DNP in aqueous solution and decreased its adsorption to alpha-cellulose, which we used as an example of an insoluble dietary fiber. Gum arabic was the most effective and kappa-carrageenan the least. The capacity of the polysaccharides to act as emulsifiers and stabilizers may explain their effects on DNP distribution. The monosaccharide glucose and the disaccharide cellobiose had no effect on the distribution of DNP. These results indicate three possible mechanisms by which soluble-fiber polysaccharides may enhance the development of colorectal cancer. First, because they reduce the ability of insoluble dietary fibers to adsorb hydrophobic carcinogens, more carcinogens may enter the colon maintained in solution than adsorbed onto insoluble fibers. Second, if soluble-fiber polysaccharides are maintaining hydrophobic carcinogens in solution and these polysaccharides are degraded by bacterial enzymes in the colon, then the carcinogens may come out of solution and be deposited onto the mucosal surface of the colon. Third, soluble-fiber polysaccharides may cross the intestinal epithelium and carry with them carcinogens maintained in solution. These studies have important consequences for nutrition, because soluble-fiber polysaccharides represent a common component of foods.

A continuous model for interpreting the positions of bands in DNA locus-specific work

A simple but rigorous approach is offered for evaluating the evidential value of single locus DNA autoradiographs. This approach does not use a binning technique and it does not treat alleles as discrete variables. Instead, the allele distribution is considered to be continuous. The variation between two comparable bands is assessed using previously determined experimental parameters. The Bayesian treatment leads to an expression of the "quality of a match".

Experimental bacterial infection of the biliary tract

The bacterial species commonly found in the human obstructed biliary tract were studied in an animal model of acute hepato-cholangitis. A rank order of their virulence and persistence in the bile and liver was shown which corresponded well to the clinical effects in the animals and also to the prevalence of bile bacteria in the benign bile duct stricture of man. Anaerobic organisms were found to be of low pathogenicity.