A pilot study on the effectiveness of a language-specific (Chinese) pulmonary rehabilitation programme for individuals with chronic pulmonary disease: a 2-year prospective cohort study in Sydney, Australia

BACKGROUND AND AIMS

Pulmonary rehabilitation (PR) improves dyspnoea, fatigue and healthcare-related quality of life (QoL) in patients with chronic lung disease (CLD). Non-English-speaking background (NESB) patients face language and cultural barriers that hinder their access to PR programmes, contributing to health disparities. Our trial aimed to demonstrate the effectiveness and feasibility of a Chinese language-specific PR programme on lung function, functional exercise capacity and QoL measures.

METHODS

A prospective cohort study was conducted over a 2-year period. Participants were enrolled in an 8-week PR programme with biweekly sessions conducted by Chinese-speaking physiotherapists. Baseline and post-rehabilitation testing included pulmonary function testing, 6-min walk test (6MWT), St. George Respiratory Questionnaire (SGQR) and Short Form Health Survey (SF-36).

RESULTS

We enrolled 76 patients (58% male) with a median age of 77 years (interquartile range (IQR) 68-81) and achieved a completion rate of 86.8% (n = 66). CLD included chronic obstructive pulmonary disease (42%), asthma (15%) and interstitial lung disease (3%). Baseline median forced expiratory volume in 1 s (FEV1) was 1.63 L (IQR 1.17-2.05), and the median 6MWT was 282 m (IQR 232-332). Post-intervention median 6MWT increased to 332 m (IQR 290-390), and the median FEV1 was 1.99 L (IQR 1.3-2.1). Both QoL measures (SGQR and SF-36) showed significant improvement after intervention (P < 0.05).

CONCLUSION

Our study demonstrates that a language-specific PR programme is feasible, improving outcomes in NESB patients with CLD. The improvement in 6MWT and QoL measures was comparable to English-based programmes. Ensuring equal access to healthcare programmes, regardless of cultural background or language barriers, is crucial in promoting health equity.

Abstract P033: Characterizing the relationship between arsenic exposure and breast cancer risk in Canada

Background: Although an established carcinogen for cancers of the skin, bladder and lungs, the relationship between arsenic exposure and breast cancer risk is not known. Studies to date have been conducted in populations with endemically high levels of arsenic, have been limited by small sample sizes and methodological concerns. The impact of chronic exposure to low levels of arsenic remains unclear. This project aims to: 1) describe arsenic exposure in Canada and 2) to evaluate the association between urinary arsenic levels and breast cancer risk among Canadian women. Methods: The Canadian Health Measures Survey (CHMS) is a nationally representative cross-sectional survey that collects self-reported and objective health measures, including biomonitoring data, from participants in biennial cycles. To date, CHMS has collected data from approximately 25,000 participants between the ages of 3 – 80 years. This analysis utilized demographic, lifestyle and reproductive data collected from Cycles 1-5 (2007-2017). Urinary arsenic levels (µg/L) were quantified using high-performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP-MS). Incident breast cancers were ascertained through linkage to the Canadian Cancer Registry and the Discharge Abstract Database. Participants were eligible for inclusion if they were female, older than 18 at the time of urine sample collection, had no personal history of any cancer, and had quantified urinary arsenic and creatinine levels. Arsenic exposure was described using weighted percentiles and then categorized by tertiles. Cox proportional hazards regression was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) of arsenic exposure and breast cancer risk. Multivariate models adjusted for relevant confounders. Quantile g-computation will be used to estimate the joint association between multiple metals and breast cancer risk. Results: This analysis included 5,100 women with a mean age of 44.6 years and an average follow-up of 6.6 years. The median total urinary arsenic level was 7.8 µg/g of creatinine (2.70 µg/g – 84.83 µg/g). Approximately 5% of women had elevated urinary arsenic levels above the clinically relevant threshold of 50 ug/L. Women in the highest tertile of urinary arsenic levels (&gt; 13.0 µg/L) had a significant two-fold increased risk of developing breast cancer compared to women in the referent group in age-adjusted models (HR = 2.10; 95%CI 1.06-3.96, P-trend = 0.03). Similar trends were observed in the fully adjusted models (HR= 2.05; 95%CI 1.05-3.94, P-trend = 0.035). Metal mixture analyses are ongoing, and results will be presented. Significance: To our knowledge, this represents the first analysis of arsenic levels and breast cancer risk in a nationally representative, Canadian cohort. Our findings suggest that exposure to arsenic, even at low levels, is associated with an increased risk of breast cancer and are important for informing population-level interventions to reduce the burden of breast cancer in Canada and around the globe.

Citation Format: Katherine Pullella, Vicky Chang, Anthony Hanley, Shelley Harris, Jan Lubiński, Steven Narod, Joanne Kotsopoulos. Characterizing the relationship between arsenic exposure and breast cancer risk in Canada. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr P033.

A comparison of clinical development pathways to advance tuberculosis regimen development

BACKGROUND

Current tuberculosis (TB) regimen development pathways are slow and in urgent need of innovation. We investigated novel phase IIc and seamless phase II/III trials utilizing multi-arm multi-stage and Bayesian response adaptive randomization trial designs to select promising combination regimens in a platform adaptive trial.

METHODS

Clinical trial simulation tools were built using predictive and validated parametric survival models of time to culture conversion (intermediate endpoint) and time to TB-related unfavorable outcome (final endpoint). This integrative clinical trial simulation tool was used to explore and optimize design parameters for aforementioned trial designs.

RESULTS

Both multi-arm multi-stage and Bayesian response adaptive randomization designs were able to reliably graduate desirable regimens in ≥ 95% of trial simulations and reliably stop suboptimal regimens in ≥ 90% of trial simulations. Overall, adaptive phase IIc designs reduced patient enrollment by 17% and 25% with multi-arm multi-stage and Bayesian response adaptive randomization designs respectively compared to the conventional sequential approach, while seamless designs reduced study duration by 2.6 and 3.5 years respectively (typically ≥ 8.5 years for standard sequential approach).

CONCLUSIONS

In this study, we demonstrate that adaptive trial designs are suitable for TB regimen development, and we provide plausible design parameters for a platform adaptive trial. Ultimately trial design and specification of design parameters will depend on clinical trial objectives. To support decision-making for clinical trial designs in contemporary TB regimen development, we provide a flexible clinical trial simulation tool that can be used to explore and optimize design features and parameters.

Prevalence and outcomes of WPW pattern in the young: a report from a nationwide cardiac screening programme

Funding Acknowledgements

Type of funding sources: None.

Background

Individuals with accessory pathways, also referred as the Wolff-Parkinson-White pattern (WPWp), are usually asymptomatic and fatal arrhythmias may be the first presentation. Risk stratification is recommended, with electrophysiological study (EPS) being the gold standard. Catheter ablation offers a widely available, curative option, and provides incentive for screening, particularly in high-risk populations such as athletes.

Purpose

We sought to assess the prevalence, real-world clinical practice and outcomes of WPWp in young individuals identified through a nationwide cardiac screening programme.

Method

Between 2008 and 2018, 113,209 consecutive individuals (14 to 35 years old, 38% female) underwent cardiac screening with a health questionnaire, 12-lead electrocardiogram (ECG) and cardiology consultation. Individuals with suspected cardiac disease were referred for further investigations as necessary. Clinical outcomes were obtained via an online questionnaire and matched de-identified records from the Office of National Statistics database. Individuals were classified as elite athletes, non-elite athletes and non-athletes.

Results

A total of 214 (0.2%) individuals were referred for secondary evaluation with a suspected WPWp (Figure 1). Clinical outcomes were unavailable for 30 (14%) individuals. Follow-up confirmed an additional 13 individuals with a WPWp who were deemed to have normal investigations at screening, of which 8 (61%) had reported cardiovascular symptoms on their HQ and, in retrospect, 4 (30%) demonstrated subtle WPWp on their ECG. A WPWp was confirmed in 187 individuals (0.2%), of which 149 (80%) individuals were considered non-athletes, 114 (61%) reported cardiovascular symptoms, 116 (62%) underwent risk stratification with an EPS and 95 (43%) underwent catheter ablation. Report of palpitation was significantly greater in non-athletes than athletes (p=0.034). In asymptomatic individuals, those engaging in sports at elite level were more likely to be referred for an EPS (p=0.04). Four adverse cardiac events were reported over a follow up period of 7.4 years (IQR 4.9 to 9.2), including 3 individuals (16 years, 20 years, 40 years) with life-threatening arrhythmic events (LAE) requiring cardioversion, and 1 individual (20 years) with sudden cardiac death. Of these 4 individuals, only 1 with a LAE had undergone risk stratification with EPS.

Conclusions

The incidence of SCD in this young screened population was 0.72 per 1000 person-years. Clinical practice was variable and EPS was not offered to a significant proportion of patients, despite inadequate non-invasive risk stratification. The indication to EPS was driven by the athletic status in the asymptomatic individuals. The WPW syndrome may manifest with subtle ECG changes, posing a diagnostic challenge to interpreting physicians.

Latent tuberculosis infection among contacts of patients with multidrug-resistant tuberculosis in New South Wales, Australia

Background

Contacts of an individual with active tuberculosis (TB) disease have a higher risk of developing latent TB infection (LTBI) or active TB disease. Contact tracing is a public health measure that seeks to identify exposed contacts, screen them for co-prevalent TB and consider prophylactic treatment to prevent progression from LTBI to active TB disease. The investigators sought to determine the prevalence of LTBI and active TB disease among contacts of patients with multidrug-resistant (MDR)-TB in New South Wales, Australia.

Methodology

A retrospective cohort study was performed among the contacts of patients diagnosed with MDR-TB between 2000 and 2016, inclusive, at seven chest clinics. Medical records were used to identify eligible contacts. Outcomes of screening and prophylactic treatment regimens offered to MDR-TB contacts with LTBI were characterised. Collected data included demographic information, screening tests results and initial management.

Results

In total, 247 contacts of 55 MDR-TB patients were identified. LTBI was identified in 105 contacts (42.5%). Preventive treatment was received by 20 contacts with LTBI (32.3%) in the form of various regimens, ranging from one to three antimicrobials, with various doses and durations. One contact with LTBI who was untreated progressed to active TB disease during the study period, according to clinic notes.

Conclusion

Contacts of MDR-TB patients have a high prevalence of LTBI. Management of these contacts varies substantially in New South Wales, reflecting a lack of definitive evidence for preventive therapy. Further research is required to determine the optimal management of this population.

Given the high likelihood of multidrug resistance in strains responsible for LTBI among MDR-TB contacts, new research is needed to evaluate preventive therapies for this patient populationhttps://bit.ly/2Tf4LLY

Individualised treatment for multidrug-resistant tuberculosis in New South Wales, Australia

OBJECTIVE

Multidrug-resistant tuberculosis (MDR-TB) presents a major global health challenge. In high-income countries, treatment is individualised to optimise efficacy and reduce toxicity. We aimed to evaluate the outcomes of patients with MDR-TB receiving individualised antibiotic therapy in Australia.

METHODS

This retrospective cohort study was performed in the city of Sydney in Australia and included patients diagnosed with bacteriologically confirmed MDR-TB diagnosed between 2000 and 2016. The clinical characteristics of patients and treatment details were extracted from medical records. The incidence of adverse events and end-of-treatment outcomes were also evaluated.

RESULTS

Fifty-five patients with MDR-TB were identified at TB clinics in seven hospitals. The median age was 32 years (interquartile range [IQR]: 27-36 years). The median duration of the intensive phase treatment was six months (IQR 6-7 months). All patients' treatment administration was directly observed. The commonest reported adverse event was ototoxicity (44%; 23/52) and successful treatment outcomes were achieved by 95% (52/55) of patients.

CONCLUSION

This study demonstrated the high treatment success rate that can be achieved using individualised treatment for MDR-TB in a well-resourced setting. Implications for public health: The expansion of individualised therapy promises to contribute to MDR-TB control and advance the ambitious goal of TB elimination by 2035.

Tobacco smoke exposure and sleep: estimating the association of urinary cotinine with sleep quality

INTRODUCTION

A majority of studies on tobacco smoke exposure and sleep quality have relied on self-reported smoking, resulting in potential exposure misclassification and biases related to self-report. The objective of this study was to investigate associations between urinary cotinine, a biological marker of tobacco smoke exposure, and sleep quality measures, including sleep duration, sleep continuity or efficiency, sleep satisfaction and alertness during normal waking hours.

METHODS

Using data on a national sample of 10 806 adults (aged 18-79 years) from the Canadian Health Measures Survey (2007-2013), we performed binary logistic regression analyses to estimate associations between urinary cotinine concentrations and sleep quality measures, while controlling for potential confounders. Additionally, we performed ordinal logistic regression to assess the association between urinary cotinine concentrations and increased number of sleep problems.

RESULTS

Overall, 28.7% of adult Canadian survey respondents had urinary cotinine concentrations above the limit of detection (LOD), nd the prevalence of each sleep problem ranged from 5.5% to 35.6%. Elevated urinary cotinine concentrations (quartile 4 vs. <LOD) were associated with significantly higher odds of short or long sleep duration (OR = 1.41; 95% CI: 1.02-1.95; p-trend = .021), trouble falling or staying asleep (OR = 1.71; 95% CI: 1.28-2.27; p-trend = .003), sleep dissatisfaction (OR = 1.87; 95% CI: 1.21-2.89; p-trend = .011), and increased number of sleep problems (OR = 1.64; 95% CI: 1.19-2.26; p-trend = .001). Stronger associations were observed among females compared to males.

CONCLUSION

Using a biological marker of tobacco smoke exposure, our study contributes to the body of literature of toxic environmental exposures on sleep quality by supporting an association between tobacco smoke exposure and poorer sleep quality. To address the limitations of a cross-sectional study design and to better assess the temporality of tobacco smoke exposure and sleep quality, longitudinal studies are recommended.

The Effectiveness of Individual and Environmental Infection Control Measures in Reducing the Transmission of Mycobacterium tuberculosis: A Systematic Review

Background

Transmission of Mycobacterium tuberculosis in healthcare settings is a preventable driver of the global tuberculosis epidemic. We aimed to assess the evidence for infection control interventions, including cough etiquette, engineering and personal respiratory protection measures, to prevent transmission of M. tuberculosis in healthcare settings.

Methods

Three independent systematic reviews were performed using 6 databases and clinical trials websites. Randomized trials, cohort studies, before-after studies, and case-control studies were included. Searches were performed for controlled studies evaluating respiratory hygiene, engineering, and personal respiratory protection measures. Outcome measures included the incidence of tuberculosis infection and disease. Studies involving transmission to either humans or animals were included.

Results

Evaluation of respiratory hygiene and cough etiquette interventions identified 4 human studies, with 22 855 participants, and 1 guinea pig study. Studies in humans evaluated the effects of multiple concurrent interventions. Patient use of surgical masks reduced infection by 14.8%, and tuberculosis disease was reduced by between 0.5% and 28.9%. Engineering and environmental interventions were evaluated in 10 studies of humans, including 31 776 human participants, and 2 guinea pig studies. Mechanical ventilation was associated with between 2.9% and 14% less infection. Nine studies of personal respiratory protection were included, including 33 913 participants. Infection was reduced by between 0% and 14.8% in studies where particulate respirators were used. The quality of included studies was assessed as low.

Conclusions

Respiratory hygiene, engineering, and environmental infection controls and personal respiratory protection interventions were associated with reduced transmission of M. tuberculosis and reduced tuberculosis disease in healthcare settings.

Myocardial infarction in the Wisconsin Longitudinal Study: the interaction among environmental, health, social, behavioural and genetic factors

OBJECTIVES

This study examined how environmental, health, social, behavioural and genetic factors interact to contribute to myocardial infarction (MI) risk.

DESIGN

Survey data collected by Wisconsin Longitudinal Study (WLS), USA, from 1957 to 2011, including 235 environmental, health, social and behavioural factors, and 77 single- nucleotide polymorphisms were analysed for association with MI. To identify associations with MI we utilized recursive partitioning and random forest prior to logistic regression and chi-squared analyses.

PARTICIPANTS

6198 WLS participants (2938 men; 3260 women) who (1) had a MI before 72 years and (2) had a MI between 65 and 72 years.

RESULTS

In men, stroke (LR OR: 5.01, 95% CI 3.36 to 7.48), high cholesterol (3.29, 2.59 to 4.18), diabetes (3.24, 2.53 to 4.15) and high blood pressure (2.39, 1.92 to 2.96) were significantly associated with MI up to 72 years of age. For those with high cholesterol, the interaction of smoking and lower alcohol consumption increased prevalence from 23% to 41%, with exposure to dangerous working conditions, a factor not previously linked with MI, further increasing prevalence to 50%. Conversely, MI was reported in <2.5% of men with normal cholesterol and no history of diabetes or depression. Only stroke (4.08, 2.17 to 7.65) and diabetes (2.71, 1.81 to 4.04) by 65 remained significantly associated with MI for men after age 65. For women, diabetes (5.62, 4.08 to 7.75), high blood pressure (3.21, 2.34 to 4.39), high cholesterol (2.03, 1.38 to 3.00) and dissatisfaction with their financial situation (4.00, 1.94 to 8.27) were significantly associated with MI up to 72 years of age. Conversely, often engaging in physical activity alone (0.53, 0.32 to 0.89) or with others (0.34, 0.21 to 0.57) was associated with the largest reduction in odds of MI. Being non-diabetic with normal blood pressure and engaging in physical activity often lowered prevalence of MI to 0.2%. Only diabetes by 65 (4.25, 2.50 to 7.24) and being exposed to dangerous work conditions at 54 (2.24, 1.36 to 3.69) remained significantly associated with MI for women after age 65, while still menstruating at 54 (0.46, 0.23 to 0.91) was associated with reduced odds of MI.

CONCLUSIONS

Together these results indicate important differences in factors associated with MI between the sexes, that combinations of factors greatly influence the likelihood of MI, that MI-associated factors change and associations weaken after 65 years of age in both sexes, and that the limited genotypes assessed were secondary to environmental, health, social and behavioral factors.

Phamacology of fluticasone furoate and vilanterol trifenatate combination therapy for asthma

INTRODUCTION

Fluticasone furoate (FF) is a novel inhaled corticosteroid (ICS). Vilanterol trifenate (VI) is a new inhaled, selective, long - acting β2 adrenergic agonist (LABA). It is now also marketed as a novel once daily combined ICS/LABA indicated for treatment of moderate and severe asthma.

AREAS COVERED

FF has a highly specific, fast association and slow dissociation from the glucocorticoid receptor, with a 24 hr duration of action. This, combined with a slow transport out of respiratory cells, creates a long tissue retention period. Vilanterol trifenate (VI) is a new inhaled, selective, long - acting β2 adrenergic agonist, also with a rapid onset of action with a maximal effect within 6 mins and prolonged lung retention with effects on lung function over 24 hours. Expert commentary: Multiple Phase I-III efficacy studies performed on FF and VI have shown an improvement in spirometry as well as symptom control in asthma. The development of once daily ICS/LABA combinations may potentially improve adherence to asthma therapy, but this has yet to be demonstrated.

Fluticasone furoate and vilanterol trifenatate combination therapy for the treatment of asthma

INTRODUCTION

Combination inhaled corticosteroids (ICS) and long acting β2-adrenergic agonists (LABA) are used in a stepwise fashion for patients whose asthma is not controlled by low dose ICS alone. Adherence is one of the main issues facing clinicians in the control of asthma symptoms with currently available combination inhalers requiring twice-daily (BD) inhalation. Fluticasone furoate (FF) and vilanterol trifenatate (VI) both have prolonged retention in the lung with effects on lung function over 24-hours and as such the combination has been proposed for once-daily (OD) dosing.

AREAS COVERED

The stepwise pharmacologic approach to asthma management is addressed, followed by a detailed assessment of the literature pertaining to the efficacy, tolerability and safety of FF/VI combination therapy for the treatment of asthma. Expert commentary: Doses of 100/25µg and 200/25µg inhaled OD, have similar improvements in lung function, asthma control as well as rates of side effects to one of the currently available BD ICS/LABA combinations, fluticasone propionate and salmeterol (FP/SAL) but have not been compared with other commonly used combinations. It is hoped that OD dosage of FF/VI can improve adherence and hence asthma control in these patients, however evidence to support this has yet to become available.

Controversies in the management of cervical spondylotic myelopathy

AIM

Cervical spondylotic myelopathy (CSM) is a common clinical entity that can be a significant cause of disability in the adult population. Although our CSM knowledge has markedly grown in recent years, a variety of controversies exist regarding the optimal treatment strategies. The goal of this paper is to review and discuss current areas of controversy in the management of CSM patients.

METHODS

Topics addressed in this manuscript include: operative versus nonoperative management for patients with mild CSM, optimal surgical approaches for CSM, the utility of intraoperative monitoring, and radiographical prognostic indicators for outcome following surgery for CSM.

RESULTS

A current review reveals several areas where Class I evidence exists regarding these controversies. However, many other studies consist contain Class III or weaker data, thereby making it difficult to draw any definitive conclusions. Despite the lack of a consensus in some areas, it appears that CSM patients can often achieve satisfactory treatment through a variety of different options.

CONCLUSION

CSM remains a challenging clinical problem where several areas of controversy still exist. Large, multi-center, randomized prospective trials will be required to help resolve some of the controversies.

Assessment of genetic and nongenetic interactions for the prediction of depressive symptomatology: an analysis of the Wisconsin Longitudinal Study using machine learning algorithms

OBJECTIVES

We examined depression within a multidimensional framework consisting of genetic, environmental, and sociobehavioral factors and, using machine learning algorithms, explored interactions among these factors that might better explain the etiology of depressive symptoms.

METHODS

We measured current depressive symptoms using the Center for Epidemiologic Studies Depression Scale (n = 6378 participants in the Wisconsin Longitudinal Study). Genetic factors were 78 single nucleotide polymorphisms (SNPs); environmental factors-13 stressful life events (SLEs), plus a composite proportion of SLEs index; and sociobehavioral factors-18 personality, intelligence, and other health or behavioral measures. We performed traditional SNP associations via logistic regression likelihood ratio testing and explored interactions with support vector machines and Bayesian networks.

RESULTS

After correction for multiple testing, we found no significant single genotypic associations with depressive symptoms. Machine learning algorithms showed no evidence of interactions. Naïve Bayes produced the best models in both subsets and included only environmental and sociobehavioral factors.

CONCLUSIONS

We found no single or interactive associations with genetic factors and depressive symptoms. Various environmental and sociobehavioral factors were more predictive of depressive symptoms, yet their impacts were independent of one another. A genome-wide analysis of genetic alterations using machine learning methodologies will provide a framework for identifying genetic-environmental-sociobehavioral interactions in depressive symptoms.

Hypothalamic-pituitary-gonadal axis homeostasis predicts longevity

The reproductive-cell cycle theory of aging posits that reproductive hormone changes associated with menopause and andropause drive senescence via altered cell cycle signaling. Using data from the Wisconsin Longitudinal Study (n = 5,034), we analyzed the relationship between longevity and menopause, including other factors that impact "ovarian lifespan" such as births, oophorectomy, and hormone replacement therapy. We found that later onset of menopause was associated with lower mortality, with and without adjusting for additional factors (years of education, smoking status, body mass index, and marital status). Each year of delayed menopause resulted in a 2.9% reduction in mortality; after including a number of additional controls, the effect was attenuated modestly but remained statistically significant (2.6% reduction in mortality). We also found that no other reproductive parameters assessed added to the prediction of longevity, suggesting that reproductive factors shown to affect longevity elsewhere may be mediated by age of menopause. Thus, surgical and natural menopause at age 40, for example, resulted in identical survival probabilities. These results support the maintenance of the hypothalamic-pituitary-gonadal axis in homeostasis in prolonging human longevity, which provides a coherent framework for understanding the relationship between reproduction and longevity.

Multigene interactions and the prediction of depression in the Wisconsin Longitudinal Study

OBJECTIVES

Single genetic loci offer little predictive power for the identification of depression. This study examined whether an analysis of gene-gene (G × G) interactions of 78 single nucleotide polymorphisms (SNPs) in genes associated with depression and age-related diseases would identify significant interactions with increased predictive power for depression.

DESIGN

A retrospective cohort study.

SETTING

A survey of participants in the Wisconsin Longitudinal Study.

PARTICIPANTS

A total of 4811 persons (2464 women and 2347 men) who provided saliva for genotyping; the group comes from a randomly selected sample of Wisconsin high school graduates from the class of 1957 as well as a randomly selected sibling, almost all of whom are non-Hispanic white.

PRIMARY OUTCOME MEASURE

Depression as determine by the Composite International Diagnostic Interview-Short-Form.

RESULTS

Using a classification tree approach (recursive partitioning (RP)), the authors identified a number of candidate G × G interactions associated with depression. The primary SNP splits revealed by RP (ANKK1 rs1800497 (also known as DRD2 Taq1A) in men and DRD2 rs224592 in women) were found to be significant as single factors by logistic regression (LR) after controlling for multiple testing (p=0.001 for both). Without considering interaction effects, only one of the five subsequent RP splits reached nominal significance in LR (FTO rs1421085 in women, p=0.008). However, after controlling for G × G interactions by running LR on RP-specific subsets, every split became significant and grew larger in magnitude (OR (before) → (after): men: GNRH1 novel SNP: (1.43 → 1.57); women: APOC3 rs2854116: (1.28 → 1.55), ACVR2B rs3749386: (1.11 → 2.17), FTO rs1421085: (1.32 → 1.65), IL6 rs1800795: (1.12 → 1.85)).

CONCLUSIONS

The results suggest that examining G × G interactions improves the identification of genetic associations predictive of depression. 4 of the SNPs identified in these interactions were located in two pathways well known to impact depression: neurotransmitter (ANKK1 and DRD2) and neuroendocrine (GNRH1 and ACVR2B) signalling. This study demonstrates the utility of RP analysis as an efficient and powerful exploratory analysis technique for uncovering genetic and molecular pathway interactions associated with disease aetiology.

The anticholinesterase activity of some antiadrenaline agents

The contractions of the isolated guinea-pig vas deferens in response to stimulation of the sympathetic hypogastric nerve were potentiated by low concentrations and inhibited by high concentrations of the antiadrenaline agents tolazoline, yohimbine, ergotamine, phenoxybenzamine and piperoxan. Eserine potentiated the contractions of the vas deferens produced by hypogastric nerve stimulation. The cholinesterase activity of an extract of vas deferens was decreased by the antiadrenaline agents. The potentiation of responses to sympathetic stimulation by antiadrenaline drugs, which also possess anticholinesterase activity, can be explained on the basis of a cholinergic sympathetic mechanism.

Prediction of survival by immunohistochemical stains (IHC) in stage D2 prostate cancer patients (pts): The importance of pTEN overexpression

e16019

Background: Several signal transduction pathways,important for apoptosis and angiogenesis were idendified and their expression and correlation with survival was studied by IHC in archival prostate cancer biopsies. All pts has androgen deprivation for stage D2 disease and were followed at 3 month intervals. Methods: In an IRB approved study,42 pts had adequate tissue preserved between 1992 and 2006 and their charts were reviewed retrospectively.IHC stains to detect tumor expression of S6(ribosomal),p70s6,pTEN,AKT-1,BCL-1(Cyclin D1),VEGF,c-KIT,PDGFR-alpha and PDGFR-beta were performed by US Labs(Irvine,CA).All results were independently evaluated by two pathologists.Immunoreactivity was scored using a semiquantitative system combining intensity of staining(0–3+) and percentage of cells staining positive(0–3+).The total score was obtained by adding the scores for indensity and the percentage of positive cells,then averaging the resuts obtained by each reader.For the purpose of this study, stain intensity of 0–1+ was considered negative and the intensity of 2–3+ was considered positive.A Cox regression survival model for each stain was developed with variables known to predict survival :Gleason score,Hemoglobin(Hgb),Alkaline Phosphatase(Alk Phos),Prostate Specific Antigen(PSA),Lactate Dehydrogenase(LDH) levels. Results: The median values were: age 70yrs(56–92),Gleason score 8(6–10), LDH 171 IU/L(97–350),Hgb 12.9gm/dl (6.8–16.3), PSA 188ng/ml(2–5677),Alk Phos 139U/L(60–1756),survival 851 days(163- 6102).In univariate analysis,VEGF staining was predictive of survival (p<0.037) but not in multivariate analysis.The pTEN staining correlated with survival (p<0.0367) and a hazard ratio of 0.040 in multivariate analysis. Conclusions: In this small sample of pts, overexpression of S6,p70s6,AKT-1,BCL-1,VEGF,c-KIT,PDGFR-alpha and PDGFR-beta by IHC staining did not predict survival independently.The pTEN staining,however was strong predictor of survival in the multivariate analysis.

No significant financial relationships to disclose.

Survey of disease and treatment-related symptoms in outpatients with invasive cancer of the breast, prostate, lung, or colon/rectum (E2Z02, the SOAPP study)

9619

Background: The full spectrum and impact of symptoms experienced by ambulatory patients (pts) in medical oncology clinics throughout their care trajectory is poorly understood. Methods: This large prospective study by the Eastern Cooperative Oncology Group (ECOG) enrolled pts with invasive cancer of the breast, prostate, colon/rectum or lung regardless of phase of care or stage of disease. The study was conducted between 3/06 and 5/08 at multiple academic (n=7) and community (n=32) medical oncology clinics. Pre-defined sampling algorithms were used to reduce selection bias. At baseline and again 4 weeks later, pts completed a 25-item measure of symptoms and functional interference (M.D. Anderson Symptom Inventory-ECOG). Patients’ providers simultaneously prioritized their symptoms. Results: 3124 patients were enrolled (90% from community clinics) and 3077 were analyzable with 1524 breast (50%), 715 colorectal (23%), 518 lung (17%), and 320 prostate (10%) pts. The most prevalent moderate-to-severe symptoms of the full cohort at baseline (B) and follow-up (F) were: fatigue (B34% to F32%), disturbed sleep (B27% to F21%), drowsiness (B22% to F21%), hair loss (B20% to F19%), pain (B19% to F18%), dry mouth (B19% to F15%), and numbness/tingling (B19% to F17%). At baseline, 40% of the cohort had at least 3 moderate-to-severe symptoms and 36% had this attribute at follow-up. Clinician perception of symptoms was strongly correlated with patient symptom survey results regardless of disease site, race, or ethnicity. Of the 849 pts receiving anti-cancer treatment for metastatic disease, half had 2 or more metastatic sites with 75% receiving cytotoxic chemotherapy. Clinicians judged lung cancer patients’ symptoms to be the most difficult to manage (p<0.01). Conclusions: Non-pain symptoms, particularly fatigue and sleep disturbance, are a major source of symptom distress in ambulatory medical oncology practice. Overall, symptom burden remains substantial and difficult to resolve. These data will help guide future interventional studies.

No significant financial relationships to disclose.

Etanercept associated optic neuropathy

We report the case of a 14-year-old boy who developed optic neuropathy subsequent to the use of etanercept. There have been 15 reported cases of anti-TNF-alpha-associated optic neuropathy to date and their characteristics are reviewed in this report, as well as possible pathophysiologic mechanisms behind such phenomenon. Such cases demonstrate the importance of prompt ophthalmologic evaluation of visual changes in patients being treated with anti-TNF-alpha antagonists.

Cost comparison of XELOX compared to FOLFOX4 with or without bevacizumab (bev) in metastatic colorectal cancer

4074

Background: A recent randomized 2x2 phase III trial compared oral capecitabine + IV oxaliplatin (XELOX); IV 5FU/LV/oxaliplatin (FOLFOX4), XELOX+bev, and FOLFOX4+bev. FOLFOX4 was the regulatory control. XELOX was non-inferior to FOLFOX4 for progression-free survival, and bev-containing regimens were superior to comparison arms. This economic analysis compared expected costs in XELOX vs. FOLFOX4 arms in a US setting from a payer and societal perspective. Methods: Direct medical and indirect cost estimates (for patient time and travel) were compared. Resource use and patient time were estimated based on trial data and protocols. Data collected during the trial and used in the analysis were as follows: no. of visits / duration of drug administration, central venous access management, treatment of adverse events (AE), including hospital days for treatment-related AEs and total hours of ambulatory encounters. Unit costs were based on government fee schedules (i.e. Medicare reimbursements) and other published sources. Results: Total direct medical cost estimates were similar for bi-weekly FOLFOX4 and 3-weekly XELOX: $45,800 vs. $44,500. XELOX had higher drug costs while FOLFOX had higher drug administration costs, with about 15 more visits. Costs for hospitalization and ambulatory encounters were slightly lower for FOLFOX4; other medications and venous access were slightly higher for FOLFOX4. Similar patterns held for FOLFOX4+bev vs. XELOX+bev (total direct medical cost estimates $76,100 vs. $79,200). Indirect time cost estimates were lower with XELOX due to fewer cycles and visits: estimated savings range from $1000-$5000 depending on assumptions used. Conclusion: XELOX is estimated to have similar total direct medical costs and lower indirect costs compared with FOLFOX4.

[Table: see text]

No significant financial relationships to disclose.

Mechanism of actin network attachment to moving membranes: barbed end capture by N-WASP WH2 domains

Actin filament networks exert protrusive and attachment forces on membranes and thereby drive membrane deformation and movement. Here, we show that N-WASP WH2 domains play a previously unanticipated role in vesicle movement by transiently attaching actin filament barbed ends to the membrane. To dissect the attachment mechanism, we reconstituted the propulsive motility of lipid-coated glass beads, using purified soluble proteins. N-WASP WH2 mutants assembled actin comet tails and initiated movement, but the comet tails catastrophically detached from the membrane. When presented on the surface of a lipid-coated bead, WH2 domains were sufficient to maintain comet tail attachment. In v-Src-transformed fibroblasts, N-WASP WH2 mutants were severely defective in the formation of circular podosome arrays. In addition to creating an attachment force, interactions between WH2 domains and barbed ends may locally amplify signals for dendritic actin nucleation.

Small-molecule regulation of zebrafish gene expression

The zebrafish has emerged as a versatile model organism for biomedical research, yet its potential has been limited by a lack of conditional reverse-genetic tools. Here we report a chemically inducible gene expression technology that has orthogonality to vertebrate signaling processes, high induction levels, and rapid kinetics. Coupled with tissue-specific promoters, this system provides multidimensional control of gene expression and will enable new models of human disorders and diseases.

A phase II trial of epirubicin (E), estramustine phosphate (EP), and celecoxib (C) as second line treatment of patients (pts) with hormone resistant prostate cancer (HRPC)

14567

Background: Celecoxib, epirubicin, and estramustine phosphate affect prostate cancer cells through different mechanisms. All three could be synergistic. We studied the effects of this combination on PSA, response, toxicity and survival in pts with HRPC. Methods: Pts after progression from first line taxane-based chemotherapy with rising PSA and radiographic progression were eligible. Treatment was E30 mg/m2 iv on day 1 and 8 of each 4 week cycle; EP 280 mg po bid daily × 3 days every wk × 2 followed by 2 wks rest; C 400 mg po bid daily for 28 days. All pts were assessed for response every 2 cycles. Dose modifications for hematologic and hepatorenal toxicity were made. RECIST criteria and PSA decline>50% were used to define response. Results: Sixteen pts enrolled, and 13 are evaluable for toxicity and response. Two withdrew before treatment and one for toxicity. The Median (M) age was 71.5 yrs (59–87), ECOG PS 1 (0–1), Gleason score 7 (4–9), LDH 172 (131–244), Hgb 11.1 (8.8–11.9), PSA 75 (6–814). Pts received M 4 cycles (2–10). Nine (69%) pts had soft tissue and 12 (92%) pts had bone metastases. For radiographic response, 11 pts were evaluable; 6 had stable disease and 2 had complete response by CT. Two pts had response by bone scan. Nine (69%) pts had PSA response. The M survival was 441 days (10–995). There were 5 SAE - DVT, diarrhea, bowel obstruction, cord compression and myocardial infarction. There was good renal and cardiac tolerance. Conclusions: This combination was safe and showed good and durable response as a second line regimen.

[Table: see text]

Combination therapy with docetaxel (D) and celecoxib (C) in patients (pts) with hormone resistant prostate cancer (HRPC)

14519

Background: Cox-2 expression is an independent predictor of survival and is over expressed in 89.3% of pts with HRPC. Cox-2 expression has angiogenic and cytoprotective effects. Its suppression could lead to angiogenesis inhibition and increase chemotherapy sensitivity. D in low doses and C are angiogenesis inhibitors. The main objectives were to study the effects on PSA, time to progression (TTP), toxicity and survival. Methods: In a two stage, phase II trial designed for 66 pts, 30 pts with HRPC and evidence of biochemical and radiographic progression were treated with D 30 mg/m2 IV/wk for 3 wks and C 400 mg po bid for 4 wks of each cycle. Response evaluation after every two cycles was made. RECIST criteria and PSA reduction by >50% for biochemical response were used. Independent safety monitoring for renal (R) and cardiovascular (CV) toxicity were made. Results: Thirty (30) evaluable pts received minimum of 2 cycles, median (M) 4.5 (range 2–8). The M age was 74 yr (55–94), ECOG PS 1 (0–2), Hb 11.8 g/dl (8.6–14.6), and PSA 92.5 ng/dl (15.3–4192). Metastases were present in 24 pts (80%) by bone scan and 25 pts (83.3%) by CT scan. Twelve (12) pts (40%) had PSA response of >50% and 4 pts (13.3%) had PSA normalization. By CAT scan, 3 pts (10%) had CR, 5 pts (16.7%) had PR, and 12 pts (40%) had SD. By bone scan 1 pt (4.8%) had a major response. The M TTP by PSA was 3.65 mos (0.87–12.0). With 27% pts still alive, the M survival was 10.9 mos (3.0– 30.7+), with 95% CI for the mean (9.3–15.2). One pt (3.3%) withdrew due to abdominal discomfort, 2 pts (6.6%) had grade III diarrhea and 1 pt (3.3%) had grade III nail toxicity. Conclusions: 66.7% pts had soft tissue response (CR+PR+SD), and 13.3% pts had PSA normalization. Safety analysis for R and CV toxicity demonstrated excellent safety of this regimen. Considering the unfavorable prognostic indicators of this population the MST of 10.9 mos indicates the activity of this combination.

[Table: see text]

Peroxisomal proliferator-activated receptor alpha deficiency diminishes insulin-responsiveness of gluconeogenic/glycolytic/pentose gene expression and substrate cycle flux

Our previous work led to the hypothesis that peroxisomal proliferator-activated receptor alpha (PPAR alpha) modulates insulin action in a compensatory fashion for hepatic glucose balance vs. peripheral glucose disposal. Therefore, we have examined the expression of insulin-dependent gluconeogenic/glycolytic/pentose cycle enzymes and compared these to insulin responsiveness for peripheral vs. hepatic substrate flux and futile cycling in the PPAR alpha knockout mouse. Hepatic gluconeogenic flux, glucose absorption, clearance and recycling, as well as in vivo glucose disposal were evaluated using new mass isotopomer methods. Insulin-dependent gluconeogenic/glycolytic/pentose cycle enzyme expression and glucose futile cycling were diminished; however, glucose disappearance was increased. This supports the hypothesis of hepatic insulin resistance and increased peripheral glucose uptake as compensatory events secondary to the decrease in fatty acid oxidation characteristic of the PPAR alpha knockout. We conclude that 1) the loss of PPAR alpha results in lower expression levels and diminished response to meal regulation for gluconeogenic/glycolytic enzyme expression; and 2) consequently, substrate/futile cycling of glucose is decreased when PPAR alpha is absent despite increased gluconeogenesis. The compensatory changes in liver and peripheral tissue substrate flux and the resultant adaptation for enzyme expression in the liver to have a diminished insulin dependence reflect the loosely linked correlation between phenotype and genotype in hepatic glucose metabolism.

Determination of a glucose-dependent futile recycling rate constant from an intraperitoneal glucose tolerance test

Increased glucose cycling between glucose and glucose-6-phosphate is characteristic of insulin resistance and hyperglycemia seen with Type II diabetes. Traditionally, glucose cycling is determined by the difference between hepatic glucose output measured with separate [2-3H]glucose and [6-3H]glucose infusions. We demonstrate a novel method for determining hepatic glucose recycling from an intraperitoneal glucose tolerance test (IPGTT). A single tracer, [1, 2-13C(2)]glucose (a M2 glucose isotopomer), was administered at 1mg/g body weight to 4-month-old C57BL/6 mice. Hepatic glucose recycling was monitored by the appearance of a plasma M1 isotopomer of glucose, which is produced by the action of the pentose cycle on the M2 glucose isotopomer in the liver. The initial M2 enrichment was 56% and decreased to 13% at the end of 3 h, and the M1 enrichment peaked at 2 h. The ratio of plasma M1/M2 glucose increased linearly with time to approximately 25%, and the regression of the M1/M2 ratio against time gives a slope, termed the in vivo glucose-dependent futile recycling rate constant k(HR). k(HR) estimates glucose/glucose-6-phosphate futile cycling, along with glucose recycling through the pentose cycle. These observations demonstrate complex substrate cycling during an IPGTT using a single stable isotope tracer.

Peroxisome proliferator-activated receptor alpha (PPARalpha) influences substrate utilization for hepatic glucose production

The hypoglycemia seen in the fasting PPARalpha null mouse is thought to be due to impaired liver fatty acid beta-oxidation. The etiology of hypoglycemia in the PPARalpha null mouse was determined via stable isotope studies. Glucose, lactate, and glycerol flux was assessed in the fasted and fed states in 4-month-old PPARalpha null mice and in C57BL/6 WT maintained on standard chow using a new protocol for flux assessment in the fasted and fed states. Hepatic glucose production (HGP) and glucose carbon recycling were estimated using [U-(13)C(6)]glucose, and HGP, lactate, and glycerol turnover was estimated utilizing either [U-(13)C(3)]lactate or [2-(13)C]glycerol infused subcutaneously via Alza miniosmotic pumps. At the end of a 17-h fast, HGP was higher in the PPARalpha null mice than in WT by 37% (p < 0.01). However, recycling of glucose carbon from lactate back to glucose was lower in the PPARalpha null than in WT (39% versus 51%, p < 0.02). The lack of conversion of lactate to glucose was confirmed using an [U-(13)C(3)]lactate infusion. In the fasted state, HGP from lactate and lactate production were decreased by 65 and 55%, respectively (p < 0.05) in PPARalpha null mice. In contrast, when [2-(13)C]glycerol was infused, glycerol production and HGP from glycerol increased by 80 and 250%, respectively (p < 0.01), in the fasted state of PPARalpha null mice. The increased HGP from glycerol was not suppressed in the fed state. While little change was evident for phosphoenolpyruvate carboxykinase (PEPCK) expression, pyruvate kinase expression was decreased 16-fold in fasted PPARalpha null mice as compared with the wild-type control. The fasted and fed insulin levels were comparable, but blood glucose levels were lower in the PPARalpha null mice than in controls. In conclusion, PPARalpha receptor function creates a setpoint for a metabolic network that regulates the rate and route of HGP in the fasted and fed states, in part, by controlling the flux of glycerol and lactate between the triose-phosphate and pyruvate/lactate pools.

Peroxisome proliferator-activated receptor alpha (PPARalpha) influences substrate utilization for hepatic glucose production

The hypoglycemia seen in the fasting PPARalpha null mouse is thought to be due to impaired liver fatty acid beta-oxidation. The etiology of hypoglycemia in the PPARalpha null mouse was determined via stable isotope studies. Glucose, lactate, and glycerol flux was assessed in the fasted and fed states in 4-month-old PPARalpha null mice and in C57BL/6 WT maintained on standard chow using a new protocol for flux assessment in the fasted and fed states. Hepatic glucose production (HGP) and glucose carbon recycling were estimated using [U-(13)C(6)]glucose, and HGP, lactate, and glycerol turnover was estimated utilizing either [U-(13)C(3)]lactate or [2-(13)C]glycerol infused subcutaneously via Alza miniosmotic pumps. At the end of a 17-h fast, HGP was higher in the PPARalpha null mice than in WT by 37% (p < 0.01). However, recycling of glucose carbon from lactate back to glucose was lower in the PPARalpha null than in WT (39% versus 51%, p < 0.02). The lack of conversion of lactate to glucose was confirmed using an [U-(13)C(3)]lactate infusion. In the fasted state, HGP from lactate and lactate production were decreased by 65 and 55%, respectively (p < 0.05) in PPARalpha null mice. In contrast, when [2-(13)C]glycerol was infused, glycerol production and HGP from glycerol increased by 80 and 250%, respectively (p < 0.01), in the fasted state of PPARalpha null mice. The increased HGP from glycerol was not suppressed in the fed state. While little change was evident for phosphoenolpyruvate carboxykinase (PEPCK) expression, pyruvate kinase expression was decreased 16-fold in fasted PPARalpha null mice as compared with the wild-type control. The fasted and fed insulin levels were comparable, but blood glucose levels were lower in the PPARalpha null mice than in controls. In conclusion, PPARalpha receptor function creates a setpoint for a metabolic network that regulates the rate and route of HGP in the fasted and fed states, in part, by controlling the flux of glycerol and lactate between the triose-phosphate and pyruvate/lactate pools.

G Protein beta subunit types differentially interact with a muscarinic receptor but not adenylyl cyclase type II or phospholipase C-beta 2/3

In comparison with the alpha subunit of G proteins, the role of the beta subunit in signaling is less well understood. During the regulation of effectors by the betagamma complex, it is known that the beta subunit contacts effectors directly, whereas the role of the beta subunit is undefined in receptor-G protein interaction. Among the five G protein beta subunits known, the beta(4) subunit type is the least studied. We compared the ability of betagamma complexes containing beta(4) and the well characterized beta(1) to stimulate three different effectors: phospholipase C-beta2, phospholipase C-beta3, and adenylyl cyclase type II. beta(4)gamma(2) and beta(1)gamma(2) activated all three of these effectors with equal efficacy. However, nucleotide exchange in a G protein constituting alpha(o)beta(4)gamma(2) was stimulated significantly more by the M2 muscarinic receptor compared with alpha(o)beta(1)gamma(2). Because alpha(o) forms heterotrimers with beta(4)gamma(2) and beta(1)gamma(2) equally well, these results show that the beta subunit type plays a direct role in the receptor activation of a G protein.

Survival of patients who had salvage castration after failure on bicalutamide monotherapy for stage (D2) prostate cancer

Patients with hormone-naive stage D2 prostate cancer often benefit from castration. This treatment, however, frequently produces many unacceptable physical and psychological side effects, especially in younger and sexually active patients. Bicalutamide is an oral antiandrogen with excellent tolerance and preservation of sexual function. Three institutions participated in phase II and III trials of bicalutamide monotherapy (50 mg daily) as primary therapy in hormone-naive patients with stage D2 prostate cancer. Upon bicalutamide failure, all patients underwent castration and were followed until death. Fifty-four patients received bicalutamide 50 mg orally once a day. One patient (2%) had complete response, 9 patients (17%) had partial response, and 27 patients (50%) had stable disease. Seventeen patients (31%) had progressive disease. The median time to bicalutamide failure was 47.4 weeks, 70.5 weeks for the responders vs. 25.4 weeks for the nonresponders (p < 0.001). The median survival time after the sequential use of bicalutamide and castration was 119.2 weeks for all 54 patients, 162.0 weeks for the responders, and 73.5 weeks for nonresponders (p < 0.0001). The median survival time after initiation of castration was 71.1 weeks for all 54 patients, 91.4 weeks for bicalutamide responders, and 42.1 weeks for nonresponders (p < 0.01). In hormone-naive patients with stage D2 prostate cancer, sequential treatment with bicalutamide monotherapy followed by castration upon failure may produce survival time within the range reported for initial treatment with castration. Thus, considering the favorable quality of life profile of bicalutamide, further studies are needed to define the role of sequential hormonal therapy in younger sexually active patients.

Systemic mastocytosis with involvement of the pelvis: a radiographic and clinicopathologic study--a case report

The musculoskeletal manifestations of systemic mastocytosis have been described in the literature. We present a case of systemic mastocytosis involving the pelvis. Conventional radiographs and CT imaging may demonstrate diffuse sclerotic, or mixed lytic and sclerotic lesions. On MRI, the lesions, if sclerotic, may show low signal on T1- and T2-weighted images. However, if lytic, the lesions may demonstrate low signal on T1, and increased signal on T2. As there are numerous disease entities included within the differential diagnosis, the clinical and pathological findings are crucial for establishing the correct diagnosis.

Medial arch strain after medial displacement calcaneal osteotomy: an in vitro study

Posterior tibial tendon dysfunction with concomitant progressive flatfoot deformity is associated with ligamentous failure along the medial arch. Medial displacement calcaneal osteotomy is being used alone and in combination with other procedures, with the expectation that it contributes to maintaining the arch. The objective of this study was to examine the effect of osteotomy on reducing medial arch strain. Whole cadaver feet were subjected to vertical loads while plantigrade. Spring ligament length was monitored using liquid metal displacement gauges. Two outcomes were examined: the length of the ligament under one-half body weight and the change in length of the ligament per unit of applied load. The medial displacement calcaneal osteotomy allowed elongation of the ligament with weightbearing, but at a shorter ligament length. This afforded the spring ligament protection from the levels of force experienced in the intact and lateral column-lengthened conditions.