Access to bedding and outdoor runs for growing-finishing pigs: is it possible to improve welfare without increasing environmental impacts?

Providing bedding or access to an outdoor run are husbandry aspects intended to improve pig welfare, which is currently financially supported through animal welfare schemes in several European countries. However, they may significantly affect the environment through changes in feed efficiency and manure management. Therefore, the aim of this paper was to compare farms differing in animal welfare relevant husbandry aspects regarding (1) the welfare of growing-finishing pigs and (2) environmental impact categories such as global warming (GW), acidification (AC), and freshwater (FE) and marine eutrophication (ME), by employing an attributional Life Cycle Assessment. We collected data on 50 farms with growing-finishing pigs in seven European countries. Ten animal-based welfare indicators were aggregated into three pig welfare indices using principal component analysis. Cluster analysis of farms based on husbandry aspects resulted in three clusters: NOBED (31 farms without bedding or outdoor run), BED (11 farms with bedding only) and BEDOUT (eight farms with bedding and outdoor run). Pigs on farms with bedding (BED and BEDOUT) manipulated enrichment more often (P < 0.001), pen fixtures less frequently (P = 0.003) and showed fewer oral stereotypies (P < 0.001) than pigs on NOBED farms. There were fewer pigs with a short(er) tail on farms with than without bedding (P < 0.001). Acidification of BEDOUT and BED farms was significantly higher (compared to NOBED farms P = 0.002) due to higher ammonia emissions related to farmyard manure. Also, BEDOUT farms had higher ME than NOBED farms (P = 0.035). There were no significant differences regarding GW and FE between husbandry clusters, due to the large variability within clusters regarding feed composition and conversion. Therefore, both husbandry aspects associated with improved animal welfare have a significant influence on some environmental impacts, such as acidification and marine eutrophication. Nevertheless, the large variation within clusters suggests that trade-offs may be minimised through e.g. AC and ME.

Impact of Hydrocodone Rescheduling on Dental Prescribing of Opioids.

INTRODUCTION: In the United States, dentists frequently prescribe hydrocodone. In October 2014, the US Drug Enforcement Administration rescheduled hydrocodone from controlled substance schedule III to II, introducing more restricted prescribing and dispensing regulations, which may have changed dental prescribing of opioids. OBJECTIVE: The study aim was to evaluate the impact of the hydrocodone rescheduling on dental prescribing of opioids in the United States. METHODS: This was a cross-sectional study of opioids prescribed by dentists between October 2012 and October 2016, using the IQVIA Longitudinal Prescription Dataset. Monthly dentist-based opioid prescribing rate (opioid prescription [Rx]/1,000 dentists) and monthly average opioid dosages per prescription (mean morphine milligram equivalent per day [MME/d]) were measured in the 24 mo before and after hydrocodone rescheduling in October 2014 (index or interruption). An interrupted time-series analysis was conducted using segmented ordinary least square regression models, with Newey-West standard errors to handle autocorrelation. RESULTS: Dentists prescribed 50,412,942 opioid prescriptions across the 49 mo. Hydrocodone was the most commonly prescribed opioid pre- and postindex (74.9% and 63.8%, respectively), followed by codeine (13.8% and 21.6%), oxycodone (8.1% and 9.5%), and tramadol (2.9% and 4.8%). At index, hydrocodone prescribing immediately decreased by -834.8 Rx/1,000 dentists (95% confidence interval [CI], -1,040.2 to -629.4), with increased prescribing of codeine (421.9; 95% CI, 369.7-474.0), oxycodone (85.3; 95% CI, 45.4-125.2), and tramadol (111.8; 95% CI, 101.4-122.3). The mean MME increased at index for all opioids except for hydrocodone, and dosages subsequently decreased during the postindex period. CONCLUSION: Following the rescheduling, dentist prescribing of hydrocodone declined while prescribing of nonhydrocodone opioids increased. Understanding the impact of this regulation informs strategies to ensure appropriate prescribing of opioids for dental pain. KNOWLEDGE TRANSFER STATEMENT: The study findings can be used by policy makers to make informed decisions in developing future risk mitigation strategies aimed to regulate opioid prescribing behaviors. Furthermore, dentist-specific resources and guidelines are needed subsequent to these policies in order to meet the dental population needs.

Current capabilities of the residual stress diffractometer at the high flux isotope reactor.

The engineering diffractometer 2nd Generation Neutron Residual Stress Facility (NRSF2) at the Oak Ridge National Laboratory's High Flux Isotope Reactor was built specifically for the mapping of residual strains. NRSF2 is optimized to investigate a wide range of engineering materials by providing the user a selection of monochromatic neutron wavelengths to maintain the selected Bragg reflection near 2θ = 90°, which is the optimal scattering geometry for strain mapping. Details of the instrument configuration and operation are presented, and considerations for experimental planning are also discussed. Selected examples of recent residual stress work completed with NRSF2 are presented to highlight capabilities.

Transcriptional profile of glucose-shocked and acid-adapted strains of Streptococcus mutans.

The aciduricity of Streptococcus mutans is an important virulence factor of the organism, required to both out-compete commensal oral microorganisms and cause dental caries. In this study, we monitored transcriptional changes that occurred as a continuous culture of either an acid-tolerant strain (UA159) or an acid-sensitive strain (fabM::Erm) moved from steady-state growth at neutral pH, experienced glucose-shock and acidification of the culture, and transitioned to steady-state growth at low pH. Hence, the timing of elements of the acid tolerance response (ATR) could be observed and categorized as acute vs. adaptive ATR mechanisms. Modulation of branched chain amino acid biosynthesis, DNA/protein repair mechanisms, reactive oxygen species metabolizers and phosphoenolpyruvate:phosphotransferase systems occurred in the initial acute phase, immediately following glucose-shock, while upregulation of F1 F0 -ATPase did not occur until the adaptive phase, after steady-state growth had been re-established. In addition to the archetypal ATR pathways mentioned above, glucose-shock led to differential expression of genes suggesting a re-routing of resources away from the synthesis of fatty acids and proteins, and towards synthesis of purines, pyrimidines and amino acids. These adjustments were largely transient, as upon establishment of steady-state growth at acidic pH, transcripts returned to basal expression levels. During growth at steady-state pH 7, fabM::Erm had a transcriptional profile analogous to that of UA159 during glucose-shock, indicating that even during growth in rich media at neutral pH, the cells were stressed. These results, coupled with a recently established collection of deletion strains, provide a starting point for elucidation of the acid tolerance response in S. mutans.

Increased attentional network functioning related to symptom severity measures in females with irritable bowel syndrome.

BACKGROUND: Increased attention to gastrointestinal (GI) symptoms and disease-specific contexts may play an important role in the enhanced perception of visceral stimuli frequently reported in patients with irritable bowel syndrome (IBS). In this study, we test the hypothesis that altered attentional mechanisms underlie central pain amplification in IBS. METHODS: To evaluate brain networks that support alerting, orienting, and executive attention, we employed the attention network test (ANT), a modified flanker task which measures the efficiency of functioning of core attentional networks, during functional magnetic resonance imaging in 15 IBS patients (mean age = 31 [11.96]) and 14 healthy controls (HCs; mean age = 31 [10.91]). KEY RESULTS: Patients with IBS, compared to HCs, showed shorter reaction times during the alerting and orienting conditions which were associated with greater activation of anterior midcingulate and insular cortices, and decreased activity in the right inferior frontal junction and supplementary motor cortex. Patients also showed activation in the dorsal medial prefrontal cortex and concurrent thalamic deactivation during the executive control portion of the ANT relative to HCs, but no group difference in reaction times were found. The activity in brain regions showing group differences during the ANT were associated with measures of GI-specific anxiety, pain catastrophizing, and fear of uncertainty. In IBS, activity in the anterior midcingulate during alerting correlated with duration of GI-symptoms and overall symptom severity. CONCLUSIONS & INFERENCES: Together, these results suggest that IBS patients have specific abnormalities in attentional network functioning and these deficits may underlie symptom-related anxiety, hypervigilance, and visceral hypersensitivity.

Functional profiling in Streptococcus mutans: construction and examination of a genomic collection of gene deletion mutants.

A collection of tagged deletion mutant strains was created in Streptococcus mutans UA159 to facilitate investigation of the aciduric capability of this oral pathogen. Gene-specific barcoded deletions were attempted in 1432 open reading frames (representing 73% of the genome), and resulted in the isolation of 1112 strains (56% coverage) carrying deletions in distinct non-essential genes. As S. mutans virulence is predicated upon the ability of the organism to survive an acidic pH environment, form biofilms on tooth surfaces, and out-compete other oral microflora, we assayed individual mutant strains for the relative fitness of the deletion strain, compared with the parent strain, under acidic and oxidative stress conditions, as well as for their ability to form biofilms in glucose- or sucrose-containing medium. Our studies revealed a total of 51 deletion strains with defects in both aciduricity and biofilm formation. We have also identified 49 strains whose gene deletion confers sensitivity to oxidative damage and deficiencies in biofilm formation. We demonstrate the ability to examine competitive fitness of mutant organisms using the barcode tags incorporated into each deletion strain to examine the representation of a particular strain in a population. Co-cultures of deletion strains were grown either in vitro in a chemostat to steady-state values of pH 7 and pH 5 or in vivo in an animal model for oral infection. Taken together, these data represent a mechanism for assessing the virulence capacity of this pathogenic microorganism and a resource for identifying future targets for drug intervention to promote healthy oral microflora.

Regulation of fatty acid biosynthesis by the global regulator CcpA and the local regulator FabT in Streptococcus mutans.

SMU.1745c, encoding a putative transcriptional regulator of the MarR family, maps to a location proximal to the fab gene cluster in Streptococcus mutans. Deletion of the SMU.1745c (fabTS m ) coding region resulted in a membrane fatty acid composition comprised of longer-chained, unsaturated fatty acids (UFA), compared with the parent strain. Previous reports have indicated a role for FabT in regulation of genes in the fab gene cluster in other organisms, through binding to a palindromic DNA sequence. Consensus FabT motif sequences were identified in S. mutans in the intergenic regions preceding fabM, fabTSm and fabK in the fab gene cluster. Chloramphenicol acetyltransferase (cat) reporter fusions, using the fabM promoter, revealed elevated transcription in a ∆fabTS m background. Transcription of fabTS m was dramatically elevated in cells grown at pH values of 5 and 7 in the ∆ fabTS m background. Transcription of fabTS m was also elevated in a strain carrying a deletion for the carbon catabolite repressor CcpA. Purified FabTS m and CcpA bound to the promoter regions of fabTS m and fabM. Hence, the data indicate that FabTS m acts as a repressor of fabM and fabTS m itself and the global regulator CcpA acts as a repressor for fabTS m .

Emergency pretreatment for contrast allergy before direct percutaneous coronary intervention for ST-elevation myocardial infarction.

Patients with previous adverse contrast reactions occasionally present with ST-segment elevation myocardial infarction. Whether they can undergo catheterization safely using current contrast and medications is unknown. We reviewed catheterization laboratory records of all 501 patients (January 2005 to December 2006) presenting with ST-segment elevation myocardial infarction who underwent emergency coronary angiography. Six patients (1.2%) reported a previous contrast reaction including rash, acute bronchospasm, or anaphylaxis. All received a combination of intravenous steroids and H1 and H2 blockers in the emergency department or catheterization laboratory before catheterization. None of these had complications or evidence of allergy in any patient. In conclusion, some patients with previous contrast reaction may undergo emergency catheterization without adverse consequences, although the safety of this approach has not been proved.

A comparison between the short term and long term benefits of screening for abdominal aortic aneurysms from the Huntingdon Aneurysm screening programme.

BACKGROUND: The UK Multicentre Aneurysm Screening Study (MASS) showed a 44% reduction in AAA-related mortality after 4 years and predicted an increased number of deaths prevented in the longer term. We aim to compare the 5 and 13 years benefit from aneurysm screening in the Huntingdon Aneurysm screening programme. METHODS: Incidence and mortality of ruptured AAA (RAAA) after 5 and 13 years of screening in a population based aneurysm screening program. RESULTS: Five years of screening resulted in a reduction in the incidence of RAAA of 49% (95% CI: 3-74%). Nine out of 11 ruptures in the invited group did not survive (mortality 82%; 95% CI: 48-98%) compared to 38 non-survivors from 51 ruptures in the control group (mortality 75%; 95% CI: 60-86%). Five years of screening resulted in an RAAA-related mortality reduction of 45% (95% CI: -15 to 74%). After 13 years of screening the incidence of RAAA was reduced by 73% (95% CI: 58-82%). Twenty-one out of 29 ruptures in the invited group did not survive (mortality 72%; 95% CI: 53-87%) compared to 64 non-survivors from 82 ruptures in the control group (mortality 78%; 95% CI: 68-86%). Thirteen years screening resulted in a reduction of mortality from RAAA of 75% (95% CI: 58-84%). The number needed to screen to prevent one death reduced from 1380 after 5 years to 505 after 13 years. The number of elective AAA operations needed to prevent one death reduced from 6 after 5 years to 4 after 13 years. CONCLUSION: AAA screening becomes increasingly beneficial as screening continues over the longer term. Benefits continue to increase after screening has ceased.

Dietary folate and vitamin B6 are independent predictors of peripheral arterial occlusive disease.

BACKGROUND: It has been suggested that hyperhomocysteinemia (HHcy) is an independent risk factor for peripheral arterial occlusive disease (PAOD). However, the relationship between dietary folate and vitamin B6, cofactors in the metabolism of homocysteine (Hcy), and PAOD is unclear. AIMS: To study the relationship between dietary folate and B6 and PAOD. METHODS: Case-control population based study of 392 men older than 50 years living in Huntingdon, United Kingdom. PAOD, defined as an ankle-brachial pressure index (ABPI) < 0.9, was present in 86 (22%) of subjects. Folate, vitamin B6, and vitamin B12 intakes were calculated by means of the EPIC (European Prospective Investigation into Cancer) food frequency questionnaire. RESULTS: Daily folate intake was significantly lower in case subjects (mean, 288; 95% confidence interval [CI], 266-309 microg) than in control subjects (324; 95% CI, 313-335 microg). Daily vitamin B6 intake was also lower in case subjects (2.05; 95% CI, 1.92-2.19 mg versus 2.26; 95% CI, 2.19-2.33 mg). Daily folate and vitamin B6 intakes were independent predictors of PAOD after adjusting for age, blood pressure, cholesterol levels, diabetes, and smoking status in a logistic regression model. This model suggests that increasing daily folate intake by 1 standard deviation decreased the risk of PAOD by 46%. A similar increase in daily vitamin B6 intake decreased the risk of PAOD by 29%. CONCLUSION: In men older than 50 years, dietary folate and B6 intakes are independent predictors of PAOD. Longitudinal studies are required to determine whether dietary modification can reduce the incidence of PAOD in the population.

Effectiveness and cost of screening for abdominal aortic aneurysm: results of a population screening program.

OBJECTIVES: We undertook this study to calculate the cost per life-year gained in the first round of a screening program for abdominal aortic aneurysm (AAA) and to estimate the costs in a subsequent round. METHODS: This was an intervention study, with follow-up for ruptured aneurysms. Men older than 50 years were screened for asymptomatic AAA. Outcome measures included cost per life-year saved and number of men needed to be screened to save one life. RESULTS: The incidence of ruptured AAA was 2.6 per 10,000 person- years in the screening group and 7.1 per 10,000 person-years in the control group. Screening is estimated to have prevented 10.8 ruptured AAA and 8 deaths per year, gaining 51 life-years per year for the study population, and to have reduced the incidence of ruptured AAA by 64% (95% CI, 42%-77%). Each life-year gained during the first screening round cost $1107. To save one life, 1000 men need to be screened and 5 elective operations performed. We predict that a second round of screening can be cost neutral. CONCLUSIONS: The cost-effectiveness of screening for AAA compares favorably with screening programs for other disorders in adults.

Accuracy of serial screening for abdominal aortic aneurysms by ultrasound.

OBJECTIVES: To assess the accuracy of screening for abdominal aortic aneurysms (AAAs) by ultrasound (US). SETTING: An aneurysm screening programme in Huntingdon. METHODS: False negative tests were identified by tracing all patients with a ruptured aneurysm who were screened and then finding the number classified as normal on US. False positive tests were identified by calculating the number of aneurysmal aortas on US that were classified as normal on CT. Measurement variability of the infrarenal aortic diameter between US and CT was estimated. RESULTS: 14 out of 93 patients with a ruptured AAA since 1991 had been screened. No ruptured aneurysm had been classified as normal on US. All 64 patients with an AAA larger than 4.5 cm on US had their aneurysm confirmed on CT. The mean difference between CT and US measurements was 4 mm. The limit of variability between CT and US was 12 mm. CONCLUSION: No false negative scans were found using a cut off point of 3 cm as abnormal. No false positives were found if subjects with an AAA exceeding 4.5 cm were referred for further procedures. A serial US screening policy has excellent screening performance, justifying its use as a screening tool.

Heavy mining vehicle controls and skidding accidents.

This paper examines various control locations in heavy mining vehicles. Three trucks have been tested on a skid pad in both clockwise and anticlockwise directions. The skid lengths were measured after each trial. The primary focus of the study was the positioning of various controls and their relevance to various skid lengths. Some additional measures such as NASA-TLX scales were also used to make subjective evaluations. The results are presented in this paper. The findings clearly indicate the relevance of control locations to actual skid lengths. The poorly located controls resulted in greater skid lengths. This is an important finding as skid lengths are related to greater reaction times in a skidding situation and hence greater risk of accidents on relevant trucks. Such accidents can incur large repair bills for damaged equipment whereas more importantly, jeopardizing the life and safety of heavy mining vehicle drivers.

The incidence of small abdominal aortic aneurysms and the change in normal infrarenal aortic diameter: implications for screening.

AIM: to study the incidence of small abdominal aortic aneurysms (AAA), and to investigate what proportion of normal infrarenal aortic diameters (IAD) expand with age. METHODS: longitudinal follow-up in a population-based aneurysm screening programme. The infrarenal aortic diameter (IAD) was measured by ultrasound. A second scan was performed in subjects with a normal aorta after an average of 5.5 years. RESULTS: data were analysed from 4072 subjects, 464 with a small AAA and 3608 with a normal aorta. The infrarenal aorta expanded in 15% of subjects, but significant growth (>5 mm) occurred in only 7%. Age and initial diameter were independent predictors for aortic dilatation. The effect of diameter at first screen was non-linear. The relative risk for expansion increased dramatically for IADs over 2.5 cm (test for departure of trend: chi2=52, p<0.0001). The effect of age was also non-linear, the risk of expansion was highest in the 60-69 year old age group; test for departure of trend (chi2=13, p=0.002). The incidence of new aneurysms was 3.5 per 1000 person-years (py) (95% CI: 2.8-4.4). The highest incidence of new aneurysms was found in the 60 to 69 year old age group. CONCLUSION: only a small proportion of the population is prone to aortic dilatation. Patients over 70 with an IAD <2.5 cm can be discharged from follow-up.

Early changes in neuropeptide mRNA expression in the striatum following reserpine treatment.

Chronic dopamine depletion produces neurochemical changes within the striatum as well as enhanced behavioral and metabolic responses to dopamine agonists. Changes in striatal neuropeptides have been consistently described, including increased expression of preproenkephalin mRNA and decreased expression of preprotachykinin and prodynorphin mRNA. Acute dopamine depletion following treatment with reserpine also produces enhanced behavioral and metabolic responses to agonist treatment which develop rapidly. In the present study, we used in situ hybridization histochemistry to investigate whether acute neurochemical changes occur following reserpine treatment. We evaluated neuropeptide mRNA expression in the striatum and nucleus accumbens at several time points from 6 to 120 h following single doses of reserpine and AMPT. The aim of these studies was to determine if changes in neuropeptide mRNA expression occur following acute dopamine depletion and whether such changes are specific to the striatum. Changes in striatal neuropeptide mRNA expression developed rapidly. Preproenkephalin mRNA expression by striatopallidal neurons was unchanged at 48 h, but increased by 44% at 120 h. Preprotachykinin mRNA expression in striatonigral neurons was increased at 6 h and then fell, with a maximal decrease of 45% at 48 h and partial recovery by 120 h. Prodynorphin mRNA expression was unchanged. Expression of preproenkephalin and preprotachykinin mRNA was also examined in subregions of the striatum and the nucleus accumbens. Expression of preproenkephalin mRNA was uniform in the striatum and higher in the core than the shell of the nucleus accumbens. Preprotachykinin mRNA expression in the striatum was higher in the lateral quadrants and was higher in the shell than in the core of the nucleus accumbens. The changes in neuropeptide mRNA following treatment with reserpine were only found in the striatum. These data provide further evidence for early alterations in neuronal function in the striatum following acute dopamine depletion and suggest that neuropeptide expression by striatonigral neurons may be more rapidly regulated in response to changes in dopamine levels.

JCPDS-ICDD Research Associateship (Cooperative Program with NBS/NIST).

The Research Associateship program of the Joint Committee on Powder Diffraction-International Centre for Diffraction Data (JCPDS-ICDD, now known as the ICDD) at NBS/NIST was a long standing (over 35 years) successful industry-government cooperation. The main mission of the Associateship was to publish high quality x-ray reference patterns to be included in the Powder Diffraction File (PDF). The PDF is a continuing compilation of patterns gathered from many sources, compiled and published by the ICDD. As a result of this collaboration, more than 1500 high quality powder diffraction patterns, which have had a significant impact on the scientific community, were reported. In addition, various research collaborations with NBS/NIST also led to the development of several standard reference materials (SRMs) for instrument calibration and quantitative analyses, and computer software for data collection, calibration, reduction, for the editorial process of powder pattern publication, analysis of powder data, and for quantitative analyses. This article summarizes information concerning the JCPDS-ICDD organization, the Powder Diffraction File (PDF), history and accomplishments of the JCPDS-ICDD Research Associateship.

Standard Reference Material (SRM 1990) For Single Crystal Diffractometer Alignment.

An international project was successfully completed which involved two major undertakings: (1) a round-robin to demonstrate the viability of the selected standard and (2) the certification of the lattice parameters of the SRM 1990, a Standard Reference Material(®) for single crystal diffractometer alignment. This SRM is a set of ≈3500 units of Cr-doped Al2O3, or ruby spheres [(0.420.011 mole fraction % Cr (expanded uncertainty)]. The round-robin consisted of determination of lattice parameters of a pair of crystals: the ruby sphere as a standard, and a zeolite reference to serve as an unknown. Fifty pairs of crystals were dispatched from Hauptman-Woodward Medical Research Institute to volunteers in x-ray laboratories world-wide. A total of 45 sets of data was received from 32 laboratories. The mean unit cell parameters of the ruby spheres was found to be a=4.7608 ű0.0062 Å, and c=12.9979 ű0.020 Å (95 % intervals of the laboratory means). The source of errors of outlier data was identified. The SRM project involved the certification of lattice parameters using four well-aligned single crystal diffractometers at (Bell Laboratories) Lucent Technologies and at NRC of Canada (39 ruby spheres), the quantification of the Cr content using a combined microprobe and SEM/EDS technique, and the evaluation of the mosaicity of the ruby spheres using a double-crystal spectrometry method. A confirmation of the lattice parameters was also conducted using a Guinier-Hägg camera. Systematic corrections of thermal expansion and refraction corrections were applied. These rubies- are rhombohedral, with space group [Formula: see text]. The certified mean unit cell parameters are a=4.76080±0.00029 Å, and c=12.99568 ű0.00087 Å (expanded uncertainty). These certified lattice parameters fall well within the results of those obtained from the international round-robin study. The Guinier-Hägg transmission measurements on five samples of powdered rubies (a=4.7610 ű0.0013 Å, and c = 12.9954 ű0.0034 Å) agreed well with the values obtained from the single crystal spheres.

The association between connective tissue laxity and the risk of an abdominal aortic aneurysm.

AIMS: to investigate whether connective tissue laxity is associated with abdominal aortic aneurysms (AAA). METHODS: a nested case control study in a population-based screening programme. The presence of pes planus, scoliosis, pectus deformities, flexible auricular cartilages and Gorling's sign were combined with the Beighton joint mobility score to form a connective tissue laxity score. The association between connective tissue laxity and the risk of AAA was investigated through a logistic regression model. Type III collagen turnover was assessed using a serum radio-immunoassay for type III procollagen (PIIINP). RESULTS: data from 231 controls (aortic diameter <2.5 cm) and 190 cases (AAA >2.9 cm) were analysed. Odds ratios (OR), adjusted for known confounders were 3.1 (95% CI: 1. 1-8.6) for the highest group of connective tissue scores and 2.4 (95% CI: 1.0-5.4) for the middle group, compared with those with no signs of abnormal connective tissue function. There was no difference in mean collagen turnover between cases and controls, nor between those with a stable AAA >4 cm and those with an expanding AAA. CONCLUSION: connective tissue laxity is associated with a higher risk of having an AAA. The collagen turnover is similar in subjects with an AAA and controls. Aneurysms may be associated with abnormal connective tissue rather than an increased breakdown of normal collagen.