Safety and Efficacy of Ketamine Without Intubation in the Management of Refractory Seizures: A Case Series

BACKGROUND

Continuous infusion ketamine has demonstrated efficacy in the management of refractory seizures yet does not suppress respiratory drive like other continuous infusion anesthetics (CIAs) used for this indication. The aim of this study is to describe the safety and efficacy of ketamine infusions in patients with refractory seizure without intubation.

METHODS

We analyzed a retrospective cohort of adult patients who were not intubated at the time of initiation of a ketamine infusion for refractory seizures. Seizure onset was determined to be the first clinical seizure or nonconvulsive seizure reported on electroencephalography (EEG) or the start time of EEG for patients with seizures at EEG initiation. Responders were defined as patients with resolution of seizures within 24 h of initiation without the need for intubation or an additional CIA.

RESULTS

A total of 28 patients were analyzed (median age 62 years, 64.3% female, 82.1% African American, 82.1% with structural seizure etiology, and 85.7% focal seizures). Of patients, 78.5% received an initial bolus averaging 0.9 mg/kg, and the majority (89.3%) were initiated on an infusion at 10 μg/kg/minute; median duration was 39.8 h. Maximum infusion rates were 10 μg/kg/minute in 16 patients, 20 μg/kg/minute in seven patients, and 30 μg/kg/minute in five patients. Of patients, 71.4% were assessed to be ketamine responders; six of the eight nonresponders required intubation and an additional CIA. Responders were 80% more likely to have received ketamine 5 or more hours earlier than nonresponders. Hypotension (systolic blood pressure < 90 mmHg) occurred in 31.8% of patients receiving only ketamine, which did not correlate with duration or maximum dose of ketamine; hypertension (systolic blood pressure > 180 mmHg) occurred in 39.3%.

CONCLUSIONS

Ketamine represents a safe and effective treatment option for refractory seizures and has potential to reduce morbidity associated with intubation in a carefully selected patient population. Early initiation may increase the likelihood of success.

Time Thresholds for Using Pressure Reactivity Index in Neuroprognostication for Patients With Severe Traumatic Brain Injury

BACKGROUND AND OBJECTIVES

Severe traumatic brain injury (sTBI) represents a diffuse, heterogeneous disease where therapeutic targets for optimizing clinical outcome remain unclear. Mean pressure reactivity index (PRx) values have demonstrated associations with clinical outcome in sTBI. However, the retrospective derivation of a mean value diminishes its bedside significance. We evaluated PRx temporal profiles for patients with sTBI and identified time thresholds suggesting optimal neuroprognostication.

METHODS

Patients with sTBI and continuous bolt intracranial pressure monitoring were identified. Outcomes were dichotomized by disposition status ("good outcome" was denoted by home and acute rehabilitation). PRx values were obtained every minute by taking moving correlation coefficients of intracranial pressures and mean arterial pressures. Average PRx trajectories for good and poor outcome groups were calculated by extending the last daily averaged PRx value to day 18. Each patient also had smoothed PRx trajectories that were used to generate "candidate features." These "candidate features" included daily average PRx's, cumulative first-order changes in PRx and cumulative second-order changes in PRx. Changes in sensitivity over time for predicting poor outcome was then evaluated by generating penalized logistic regression models that were derived from the "candidate features" and maximized specificity.

RESULTS

Among 33 patients with sTBI, 18 patients achieved good outcome and 15 patients had poor outcome. Average PRx trajectories for the good and poor outcome groups started on day 6 and consistently diverged at day 9. When targeting a specificity >83.3%, an 85% maximum sensitivity for determining poor outcome was achieved at hospital day 6. Subsequent days of PRx monitoring showed diminishing sensitivities.

CONCLUSION

Our findings suggest that in a population of sTBI, PRx sensitivities for predicting poor outcome was maximized at hospital day 6. Additional study is warranted to validate this model in larger populations.

Perioperative Pressure Injury Prevention Program in a Military Medical Treatment Facility: A Quality Improvement Project

INTRODUCTION

The incidence of perioperative pressure injuries (PPIs) at a military medical treatment facility (MTF) increased from three PPI events in 2018 to five PPI events in the first half of 2019. The purpose of this quality improvement initiative was to determine whether an evidence-based PPI prevention program introduced during the second half of 2019 reduced pressure injuries compared to the previous 1.5 years that followed the standard of care for perioperative patient positioning.

METHODS

We used a multidisciplinary quality improvement PPI prevention approach that included education, Scott Triggers® patient risk assessment, application of a five-layer silicone dressing to at-risk surgical position sites, and feedback via multidisciplinary postoperative rounding.

RESULTS

There was an observed decrease in the rate of PPIs from 0.62 to 0.00 per 1,000 patient surgeries during the 26-month period that this protocol was implemented.

CONCLUSION

This project was conducted at a major MTF using a multidisciplinary PPI prevention approach that may be of value in reducing PPIs in other settings. This approach seems worthy of further investigation and may be applicable to other military MTFs and in deployed settings.

Advancing Readiness Through Military Programs: An Evidence-Based Practice Perspective

INTRODUCTION

Military nurses comprise the largest percentage of military health care providers. In the current military health care system, they have two roles: (1) Patient care in military treatment facilities (MTFs) and (2) patient care during combat operations. Although in MTFs, the military nurse's roles are similar to those of their civilian counterpart, their roles are unique and varied in the combat operational environment. These combined roles lead to questions regarding readiness training to ensure that nurses are proficient in both MTFs and combat operational settings where treatment requirements may differ. The purpose of this paper is to (1) present the current state of educational readiness programs to maintain a ready medical force that entail formal teaching programs, military-civilian partnerships, and joint exercises of combat simulations, and (2) identify gaps as presented in an evidence-based practice educational panel.

METHODS

On March 11, 2022, TriService Nursing Research Program hosted the virtual First Military Evidence-Based Practice Summit from the Uniformed Services University of the Health Sciences in Bethesda, MD. As part of the summit, an evidence-based practice education panel discussed the availability of current evidence-driven military medical readiness programs and identified gaps in the integration of military readiness for nursing personnel into the Defense Health Agency and Armed Services.

RESULTS

The panel participants discussed the separate requirements for training within the MTFs and in combat operational settings. The available training programs identified by the panel were primarily those developed in local MTF settings to meet local needs. Although these programs support the MTFs' peacetime mission, competing roles, limited time, and limited funds contributed to limited preparation of nursing personnel in skills associated with combat-related injuries and illnesses. Prolonged casualty care has become an important focus for the Department of Defense as greater considerations are directed to wartime operations in austere expeditionary environments. Although there is some training available that is specific for prolonged casualty care, the focus has been the adaptation of combat casualty care during contingency operations. A keynote here was the concept that combat casualty care training must include both development of individual skills and integration of the team since maximal care can be achieved only when the individual and the team operate as a unit. A key point was the utility of central repositories for storing information related to training a ready medical force at individual and unit levels and that these repositories could also be used to collect and facilitate the accession of current evidence-based information.

DISCUSSION

Optimal patient care at all levels of the military health system requires training that maximizes individual and unit skills specific to the environment at an MTF or in a combat operational setting. Training must be designed to incorporate evidence-driven knowledge in all military settings with guidance that is specific to the environment.

CONCLUSION

Enhanced communication of evidence-based training and knowledge is an important component of maintaining a ready medical force for broader medical support of combat contingency operations.

Immune microenvironment profiling of normal appearing colorectal mucosa biopsied over repeat patient visits reproducibly separates lynch syndrome patients based on their history of colon cancer

Introduction

Lynch syndrome (LS) is the most common hereditary cause of colorectal cancer (CRC), increasing lifetime risk of CRC by up to 70%. Despite this higher lifetime risk, disease penetrance in LS patients is highly variable and most LS patients undergoing CRC surveillance will not develop CRC. Therefore, biomarkers that can correctly and consistently predict CRC risk in LS patients are needed to both optimize LS patient surveillance and help identify better prevention strategies that reduce risk of CRC development in the subset of high-risk LS patients.

Methods

Normal-appearing colorectal tissue biopsies were obtained during repeat surveillance colonoscopies of LS patients with and without a history of CRC, healthy controls (HC), and patients with a history of sporadic CRC. Biopsies were cultured in an ex-vivo explant system and their supernatants were assayed via multiplexed ELISA to profile the local immune signaling microenvironment. High quality cytokines were identified using the rxCOV fidelity metric. These cytokines were used to perform elastic-net penalized logistic regression-based biomarker selection by computing a new measure - overall selection probability - that quantifies the ability of each marker to discriminate between patient cohorts being compared.

Results

Our study demonstrated that cytokine based local immune microenvironment profiling was reproducible over repeat visits and sensitive to patient LS-status and CRC history. Furthermore, we identified sets of cytokines whose differential expression was predictive of LS-status in patients when compared to sporadic CRC patients and in identifying those LS patients with or without a history of CRC. Enrichment analysis based on these biomarkers revealed an LS and CRC status dependent constitutive inflammatory state of the normal appearing colonic mucosa.

Discussion

This prospective pilot study demonstrated that immune profiling of normal appearing colonic mucosa discriminates LS patients with a prior history of CRC from those without it, as well as patients with a history of sporadic CRC from HC. Importantly, it suggests the existence of immune signatures specific to LS-status and CRC history. We anticipate that our findings have the potential to assess CRC risk in individuals with LS and help in preemptively mitigating it by optimizing surveillance and identifying candidate prevention targets. Further studies are required to validate our findings in an independent cohort of LS patients over multiple visits.

Electromyostimulation With Blood Flow Restriction for Patellofemoral Pain Syndrome in Active Duty Military Personnel: A Randomized Controlled Trial

INTRODUCTION

The high prevalence of patellofemoral pain in military service members results in strength loss, pain, and functional limitations during required physical performance tasks. Knee pain is often the limiting factor during high-intensity exercise for strengthening and functional improvement, thus limiting certain therapies. Blood flow restriction (BFR) improves muscle strength when combined with resistance or aerobic exercise and may serve as a possible alternative to high-intensity training during recovery. In our previous work, we showed that Neuromuscular electrical stimulation (NMES) improves pain, strength, and function in patellofemoral pain syndrome (PFPS), which led us to ask whether the addition of BFR to NMES would result in further improvements. This randomized controlled trial compared knee and hip muscle strength, pain, and physical performance of service members with PFPS who received BFR-NMES (80% limb occlusion pressure [LOP]) or BFR-NMES set at 20 mmHg (active control/sham) over 9 weeks.

METHODS

This randomized controlled trial randomly assigned 84 service members with PFPS to one of the two intervention groups. In-clinic BFR-NMES was performed two times per week, while at-home NMES with exercise and at-home exercise alone were performed on alternating days and omitted on in-clinic days. The outcome measures included strength testing of knee extensor/flexor and hip posterolateral stabilizers, 30-second chair stand, forward step-down, timed stair climb, and 6-minute walk.

RESULTS

Improvement was observed in knee extensor (treated limb, P < .001) and hip strength (treated hip, P = .007) but not flexor over 9 weeks of treatment; however, there was no difference between high BFR (80% LOP) and BFR-sham. Physical performance and pain measures showed similar improvements over time with no differences between groups. In analyzing the relationship between the number of BFR-NMES sessions and the primary outcomes, we found significant relationships with improvements in treated knee extensor strength (0.87 kg/session, P < .0001), treated hip strength (0.23 kg/session, P = .04), and pain (-0.11/session, P < .0001). A similar set of relationships was observed for the time of NMES usage for treated knee extensor strength (0.02/min, P < .0001) and pain (-0.002/min, P = .002).

CONCLUSION

NMES strength training offers moderate improvements in strength, pain, and performance; however, BFR did not provide an additive effect to NMES plus exercise. Improvements were positively related to the number of BFR-NMES treatments and NMES usage.

Pressure reactivity index for early neuroprognostication in poor-grade subarachnoid hemorrhage

BACKGROUND

Pressure reactivity index (PRx) utilizes moving correlation coefficients from intracranial pressure (ICP) and mean arterial pressures to evaluate cerebral autoregulation. We evaluated patients with poor-grade subarachnoid hemorrhage (SAH), identified their PRx trajectories over time, and identified threshold time points where PRx could be used for neuroprognostication.

METHODS

Patients with poor-grade SAH were identified and received continuous bolt ICP measurements. Dichotomized outcomes were based on ninety-day modified Rankin scores and disposition. Smoothed PRx trajectories for each patient were created to generate "candidate features" that looked at daily average PRx, cumulative first-order changes in PRx, and cumulative second-order changes in PRx. "Candidate features" were then used to perform penalized logistic regression analysis using poor outcome as the dependent variable. Penalized logistic regression models that maximized specificity for poor outcome were generated over several time periods and evaluated how sensitivities changed over time.

RESULTS

16 patients with poor-grade SAH were evaluated. Average PRx trajectories for the good (PRx < 0.25) and poor outcome groups (PRx > 0.5) started diverging at post-ictus day 8. When targeting specificities ≥88% for poor outcome, sensitivities for poor outcome consistently increased to >70% starting at post-ictus days 12-14 with a maximum sensitivity of 75% occurring at day 18.

CONCLUSIONS

Our results suggest that by using PRx trends, early neuroprognostication in patients with SAH and poor clinical exams may start becoming apparent at post-ictus day 8 and reach adequate sensitivities by post-ictus days 12-14. Further study is required to validate this in larger poor-grade SAH populations.

Immune Microenvironment Profiling of Normal Appearing Colorectal Mucosa Biopsied Over Repeat Patient Visits Reproduciably Separates Lynch Syndrome Patients Based on Their History of Colon Cancer

Introduction

Lynch syndrome (LS) is the most common hereditary cause of colorectal cancer (CRC), increasing lifetime risk of CRC by up to 70%. Despite this higher lifetime risk, disease penetrance in LS patients is highly variable and most LS patients undergoing CRC surveillance will not develop CRC. Therefore, biomarkers that can correctly and consistently predict CRC risk in LS patients are needed to both optimize LS patient surveillance and help identify better prevention strategies that reduce risk of CRC development in the subset of high-risk LS patients.

Methods

Normal-appearing colorectal tissue biopsies were obtained during repeat surveillance colonoscopies of LS patients with and without a history of CRC, healthy controls (HC), and patients with a history of sporadic CRC. Biopsies were cultured in an ex-vivo explant system and their supernatants were assayed via multiplexed ELISA to profile the local immune signaling microenvironment. High quality cytokine signatures were identified using rx COV fidelity metric. These signatures were used to perform biomarker selection by computing their selection probability based on penalized logistic regression.

Results

Our study demonstrated that cytokine based local immune microenvironment profiling was reproducible over repeat visits and sensitive to patient LS-status and CRC history. Furthermore, we identified sets of biomarkers whose differential expression was predictive of LS-status in patients when compared to sporadic CRC patients and in identifying those LS patients with or without a history of CRC. Enrichment analysis based on these biomarkers revealed an LS and CRC status dependent constitutive inflammatory state of the normal appearing colonic mucosa.

Discussion

This prospective pilot study demonstrated that immune profiling of normal appearing colonic mucosa discriminates LS patients with a prior history of CRC from those without it, as well as patients with a history of sporadic CRC from HC. Importantly, it suggests existence of immune signatures specific to LS-status and CRC history. We anticipate that our findings have the potential to assess CRC risk in individuals with LS and help in preemptively mitigating it by optimizing surveillance and identifying candidate prevention targets. Further studies are required to validate our findings in an independent cohort of LS patients over multiple visits.

Circulating insulin-like growth factors and risks of overall, aggressive and early-onset prostate cancer: a collaborative analysis of 20 prospective studies and Mendelian randomization analysis

BACKGROUND

Previous studies had limited power to assess the associations of circulating insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) with clinically relevant prostate cancer as a primary endpoint, and the association of genetically predicted IGF-I with aggressive prostate cancer is not known. We aimed to investigate the associations of IGF-I, IGF-II, IGFBP-1, IGFBP-2 and IGFBP-3 concentrations with overall, aggressive and early-onset prostate cancer.

METHODS

Prospective analysis of biomarkers using the Endogenous Hormones, Nutritional Biomarkers and Prostate Cancer Collaborative Group dataset (up to 20 studies, 17 009 prostate cancer cases, including 2332 aggressive cases). Odds ratios (OR) and 95% confidence intervals (CI) for prostate cancer were estimated using conditional logistic regression. For IGF-I, two-sample Mendelian randomization (MR) analysis was undertaken using instruments identified using UK Biobank (158 444 men) and outcome data from PRACTICAL (up to 85 554 cases, including 15 167 aggressive cases). Additionally, we used colocalization to rule out confounding by linkage disequilibrium.

RESULTS

In observational analyses, IGF-I was positively associated with risks of overall (OR per 1 SD = 1.09: 95% CI 1.07, 1.11), aggressive (1.09: 1.03, 1.16) and possibly early-onset disease (1.11: 1.00, 1.24); associations were similar in MR analyses (OR per 1 SD = 1.07: 1.00, 1.15; 1.10: 1.01, 1.20; and 1.13; 0.98, 1.30, respectively). Colocalization also indicated a shared signal for IGF-I and prostate cancer (PP4: 99%). Men with higher IGF-II (1.06: 1.02, 1.11) and IGFBP-3 (1.08: 1.04, 1.11) had higher risks of overall prostate cancer, whereas higher IGFBP-1 was associated with a lower risk (0.95: 0.91, 0.99); these associations were attenuated following adjustment for IGF-I.

CONCLUSIONS

These findings support the role of IGF-I in the development of prostate cancer, including for aggressive disease.

rxCOV is a quantitative metric for assessing immunoassay analyte fidelity

Immunoassay based bioanalytical measurements are widely used in a variety of biomedical research and clinical settings. In these settings they are assumed to faithfully represent the experimental conditions being tested and the sample groups being compared. Although significant technical advances have been made in improving sensitivity and quality of the measurements, currently no metrics exist that objectively quantify the fidelity of the measured analytes with respect to noise associated with the specific assay. Here we introduce ratio of cross-coefficient-of-variation (rxCOV), a fidelity metric for objectively assessing immunoassay analyte measurement quality when comparing its differential expression between different sample groups or experimental conditions. We derive the metric from first principles and establish its feasibility and applicability using simulated and experimental data. We show that rxCOV assesses fidelity independent of statistical significance, and importantly, identifies when latter is meaningful. We also discuss its importance in the context of averaging experimental replicates for increasing signal to noise ratio. Finally, we demonstrate its application in a Lynch Syndrome case study. We conclude by discussing its applicability to multiplexed immunoassays, other biosensing assays, and to paired and unpaired data. We anticipate rxCOV to be adopted as a simple and easy-to-use fidelity metric for performing robust and reproducible biomedical research.

Circulating free testosterone and risk of aggressive prostate cancer: Prospective and Mendelian randomisation analyses in international consortia

Previous studies had limited power to assess the associations of testosterone with aggressive disease as a primary endpoint. Further, the association of genetically predicted testosterone with aggressive disease is not known. We investigated the associations of calculated free and measured total testosterone and sex hormone-binding globulin (SHBG) with aggressive, overall and early-onset prostate cancer. In blood-based analyses, odds ratios (OR) and 95% confidence intervals (CI) for prostate cancer were estimated using conditional logistic regression from prospective analysis of biomarker concentrations in the Endogenous Hormones, Nutritional Biomarkers and Prostate Cancer Collaborative Group (up to 25 studies, 14 944 cases and 36 752 controls, including 1870 aggressive prostate cancers). In Mendelian randomisation (MR) analyses, using instruments identified using UK Biobank (up to 194 453 men) and outcome data from PRACTICAL (up to 79 148 cases and 61 106 controls, including 15 167 aggressive cancers), ORs were estimated using the inverse-variance weighted method. Free testosterone was associated with aggressive disease in MR analyses (OR per 1 SD = 1.23, 95% CI = 1.08-1.40). In blood-based analyses there was no association with aggressive disease overall, but there was heterogeneity by age at blood collection (OR for men aged <60 years 1.14, CI = 1.02-1.28; Phet  = .0003: inverse association for older ages). Associations for free testosterone were positive for overall prostate cancer (MR: 1.20, 1.08-1.34; blood-based: 1.03, 1.01-1.05) and early-onset prostate cancer (MR: 1.37, 1.09-1.73; blood-based: 1.08, 0.98-1.19). SHBG and total testosterone were inversely associated with overall prostate cancer in blood-based analyses, with null associations in MR analysis. Our results support free testosterone, rather than total testosterone, in the development of prostate cancer, including aggressive subgroups.

An Interdisciplinary Dashboard to Streamline Medication Processing at Patient Discharge: A Quality Improvement Initiative

INTRODUCTION

The purpose of this quality improvement project was to develop and evaluate the use of an electronic medication request dashboard to reduce the amount of time required for medication processing and decrease time lost to workflow interruptions during patient discharge. Delayed discharges are associated with increased health care costs and adverse patient outcomes. Processing of medication requests at discharge contributes to these delays and to workflow interruptions for nursing and pharmacy staff at the project site. Electronic dashboards have been successfully implemented in multiple medical settings to streamline patient processing and enhance communication.

MATERIALS AND METHODS

The Human Protections Office at Carl R. Darnall Army Medical Center (Fort Hood, TX) reviewed and approved the project with a non-human research determination. A multi-disciplinary workgroup with representatives from nursing, pharmacy, and health information technology (HIT) was formed to develop the dashboard. Based on a logic flow diagram of the desired communication, HIT created a medication request form and status dashboard using SharePoint and Nintex workflows. The dashboard was implemented for a 30-day pilot on a 25-bed medical/surgical nursing unit. The time required for medication processing, the time from discharge order to patient exit, the number of phone calls between nursing and pharmacy, and the usability of the medication request process were measured before and after implementation. The results were analyzed with descriptive statistics and evaluated for statistical significance with a P value ≤.05.

RESULTS

With implementation of the dashboard, the average medication processing time decreased from 125 minutes to 48 minutes (P < .0001), and the average patient discharge time decreased from 137 minutes to 117 minutes (P = .002). The usability score of the medication request process increased from 40 to 87 for nursing (P < .0001) and from 62 to 85 for pharmacy (P = .003). The total number of voice calls between nursing and pharmacy decreased from 1,115 to 434, while the total time on voice calls decreased from 33 hours and 50 minutes to 13 hours and 19 minutes (P < .0001).

CONCLUSIONS

The electronic dashboard is an effective method to enhance interdisciplinary communication during patient discharge and significantly reduces medication processing times. However, despite the medication processing time decreasing by over an hour, the discharge time only decreased by 20 minutes. Additional investigation is needed to evaluate other contributors to delayed discharge. A key limitation of this study was the convenience sampling used over a 30-day pilot on a single unit. The process has since been adopted by the entire hospital, and additional analysis could better reveal the impact to the organization. This communication system shows high usability and reduces phone call interruptions for both nursing and pharmacy staff. Additionally, this technology could easily be applied to other communication pathways or request processes across military medicine.

High-resolution CT with arch/neck/head CT angiography on a mobile stroke unit

BACKGROUND

Mobile stroke units (MSUs) performance dependability and diagnostic yield of 16-slice, ultra-fast CT with auto-injection angiography (CTA) of the aortic arch/neck/circle of Willis has not been previously reported.

METHODS

We performed a prospective observational study of the first-of-its kind MSU equipped with high resolution, 16-slice CT with multiphasic CTA. Field CT/CTA was performed on all suspected stroke patients regardless of symptom severity or resolution. Performance dependability, efficiency and diagnostic yield over 365 days was quantified.

RESULTS

1031 MSU emergency activations occurred; of these, 629 (61%) were disregarded with unrelated diagnoses, and 402 patients transported: 245 (61%) ischemic or hemorrhagic stroke, 17 (4%) transient ischemic attack, 140 (35%) other neurologic emergencies. Total time from non-contrast CT/CTA start to images ready for viewing was 4.0 (IQR 3.5-4.5) min. Hemorrhagic stroke totaled 24 (10%): aneurysmal subarachnoid hemorrhage 3, hemorrhagic infarct 1, and 20 intraparenchymal hemorrhages (median intracerebral hemorrhage score was 2 (IQR 1-3), 4 (20%) spot sign positive). In 221 patients with ischemic stroke, 73 (33%) received alteplase with 31.5% treated within 60 min of onset. CTA revealed large vessel occlusion in 66 patients (30%) of which 9 (14%) were extracranial; 27 (41%) underwent thrombectomy with onset to puncture time averaging 141±90 min (median 112 (IQR 90-139) min) with full emergency department (ED) bypass. No imaging needed to be repeated for image quality; all patients were triaged correctly with no inter-hospital transfer required.

CONCLUSIONS

MSU use of advanced imaging including multiphasic head/neck CTA is feasible, offers high LVO yield and enables full ED bypass.

Influence of Self-managed Rehabilitation on Work Efficiency in Active Duty Military With a Knee Injury

INTRODUCTION

Knee injuries associated with intense physical training are one of the most frequent injuries associated with medical encounters for military members. The purpose of this study was to evaluate four approaches to physiotherapy rehabilitation and their effects on work efficiency in active duty military with a knee injury. The four groups included neuromuscular electrical stimulation (NMES), walking with a weighted vest (WALK), combined NMES/Walk, and standard physiotherapy rehabilitation. All groups received standard physiotherapy rehabilitation.We have previously reported that quadriceps muscle strength improved over 18 weeks in the study for the three interventions relative to standard rehabilitation alone. This report presents results from an examination of work efficiency as evaluated during a step test while measuring oxygen utilization.

METHODS

A randomized controlled trial was conducted, with repeated outcome measures of work efficiency assessed at baseline, 3, 6, 12, and 18 weeks. The sample consisted of 67 active duty service members between the ages of 18 and 50 years with a knee injury. Participants were randomized to one of the four approaches to physiotherapy rehabilitation: (1) NMES was applied to the quadriceps muscle four times per week, for 30 minutes (15 minutes to each leg), consisting of 15 quadriceps muscle contractions per leg; (2) graduated strength walking using a weighted vest (WALK) was for 30 minutes, 3 to 4 days a week; (3) combined NMES with strength walking received both the NMES therapy and the weighted vest walking; and (4) standard physiotherapy consisted of progressive exercise with the number and type of sessions not controlled by the study. All four groups received the standard physiotherapy for a knee injury. The primary outcome was work efficiency, as measured by oxygen utilization during a 2-minute self-paced step test over 18 weeks. The primary analysis used repeated measures, linear mixed-effects models with a random effect for subject.

RESULTS

Both the number of steps performed and gross work efficiency improved during the study for all three intervention groups. For gross work efficiency, standard rehabilitation improved 12%, WALK showed a 19% improvement, NMES increased by 24%, and the NMES/Walk group improved by 40%.

CONCLUSIONS

All groups showed improved submaximal exercise efficiency based on oxygen utilization, with the intervention groups showing a greater improvement in work efficiency as compared to standard rehabilitation. Knee injuries can be problematic for active duty members because of reduced mobility leading to deconditioning and associated declines in work efficiency. Rehabilitative programs, including those described in this study, may minimize loss of work efficiency and fitness and promote a quicker recovery.

Tofacitinib inhibits inflammatory cytokines from ulcerative colitis and healthy mucosal explants and is associated with pSTAT1/3 reduction in T-cells

Poor translatability of animal disease models has hampered the development of new inflammatory bowel disorder (IBD) therapeutics. We describe a preclinical, ex vivo system using freshly obtained and well-characterized human colorectal tissue from patients with ulcerative colitis (UC) and healthy control (HC) participants to test potential therapeutics for efficacy and target engagement, using the JAK/STAT inhibitor tofacitinib (TOFA) as a model therapeutic. Colorectal biopsies from HC participants and patients with UC were cultured and stimulated with multiple mitogens ± TOFA. Soluble biomarkers were detected using a 29-analyte multiplex ELISA. Target engagement in CD3⁺CD4⁺ and CD3⁺CD8⁺ T-cells was determined by flow cytometry in peripheral blood mononuclear cells (PBMCs) and isolated mucosal mononuclear cells (MMCs) following the activation of STAT1/3 phosphorylation. Data were analyzed using linear mixed-effects modeling, t test, and analysis of variance. Biomarker selection was performed using penalized and Bayesian logistic regression modeling, with results visualized using uniform manifold approximation and projection. Under baseline conditions, 27 of 29 biomarkers from patients with UC were increased versus HC participants. Explant stimulation increased biomarker release magnitude, expanding the dynamic range for efficacy and target engagement studies. Logistic regression analyses identified the most representative UC baseline and stimulated biomarkers. TOFA inhibited biomarkers dependent on JAK/STAT signaling. STAT1/3 phosphorylation in T-cells revealed compartmental differences between PBMCs and MMCs. Immunogen stimulation increases biomarker release in similar patterns for HC participants and patients with UC, while enhancing the dynamic range for pharmacological effects. This work demonstrates the power of ex vivo human colorectal tissue as preclinical tools for evaluating target engagement and downstream effects of new IBD therapeutic agents.NEW & NOTEWORTHY Using colorectal biopsy material from healthy volunteers and patients with clinically defined IBD supports translational research by informing the evaluation of therapeutic efficacy and target engagement for the development of new therapeutic entities. Combining experimental readouts from intact and dissociated tissue enhances our understanding of the tissue-resident immune system that contribute to disease pathology. Bayesian logistic regression modeling is an effective tool for predicting ex vivo explant biomarker release patterns.

History of the Military Nurse Corps and the 1918 Influenza Pandemic: Lessons for the 2019 Coronavirus Pandemic

During World War I, the 1918 influenza pandemic struck the fatigued combat troops serving on the Western Front. Medical treatment options were limited; thus, skilled military nursing care was the primary therapy and the best indicator of patient outcomes. This article examines the military nursing’s role in the care of the soldiers during the 1918 flu pandemic and compares this to the 2019 coronavirus pandemic.

Pulse oximeter plethysmograph waveform and automated oscillometric sphygmomanometer for ankle-brachial index measurement

OBJECTIVES

There are limited non-invasive methods to assess lower extremity arterial injuries in the emergency department (ED) and pre-hospital setting. The ankle-brachial index (ABI) requires careful auscultation by Doppler, an approach made difficult in noisy environments. We sought to determine the agreement of the ABI measured using the pulse oximeter plethysmograph waveform (Pleth) with auscultation by Doppler in a controlled setting. A secondary outcome sought to examine the agreement of ABI by automated oscillometric sphygmomanometer (AOS) with Doppler.

METHODS

We measured blood pressure in the right upper and lower extremities of healthy volunteers using: (1) Doppler and manual sphygmomanometer; (2) Pleth and manual sphygmomanometer; and (3) AOS. The Bland-Altman approach to assessing agreement between methods was used comparing mean differences between ABI pairs to their means for Doppler versus Pleth and Doppler versus AOS. The intraclass correlation coefficient (ICC) from mixed effects models examined intra- and inter-rater reliability.

RESULTS

Among 100 participants with normal ABI the mean ABI (95%CI) were Doppler 1.11 (0.90-1.33), Pleth 1.10 (0.91-1.30), and AOS 1.10 (0.90-1.30). The ABI difference (95% CI for limits of agreement) were 0.01 (-0.20,0.18) for Doppler-Pleth and 0.02 (-0.26, 0.22) for Doppler-AOS. The ICC for the Doppler-Pleth comparison (ICC = 0.56, 95% CI 0.47-0.63) was greater than for the Doppler-AOS (ICC = 0.32, 95% CI 0.19-0.43).

CONCLUSIONS

The ABI measured using the Pleth has a high level of agreement with measurement by Doppler. The AOS and Doppler have good agreement with greater measurement variability. Pleth and AOS may be reasonable alternatives to Doppler for ABI.

Electrical Stimulation Therapies for Active Duty Military with Patellofemoral Pain Syndrome: A Randomized Trial

INTRODUCTION

Patellofemoral pain syndrome (PFPS) is a common musculoskeletal disorder among military service members that causes knee pain, quadriceps strength loss, and impaired motor performance in otherwise healthy individuals. PFPS poses a threat to the health, fitness, and subsequent readiness of the total force. The goal of rehabilitation for military service members with PFPS is to regain physical capacity of strength and function and to reduce pain, in order to restore readiness in this population. The randomized controlled trial reported here compared an active home exercise program (HEP) alone with three different electrical stimulation treatment regimens implemented concurrently with HEP postulated improvements in lower extremity strength and physical functional performance while also reducing pain in active duty military diagnosed with PFPS.

MATERIALS AND METHODS

After baseline testing, 130 active duty military members with PFPS were randomized to 1 of 4 treatment groups: (1) neuromuscular electrical stimulation (NMES) with HEP; (2) transcutaneous electrical nerve stimulation (TENS) with HEP; (3) combined NMES/TENS with HEP; (4) active HEP only. The primary outcome measure was degree of change in knee flexion and extension strength over 9 weeks. Secondary outcomes were physical functional performance and knee pain. The primary analyses used repeated measures, linear mixed-effects models with a random effect for subject, time as a continuous variable, group as a categorical variable, and a group and time interaction to test for differences in change over time among the groups.

RESULTS

All three electrical stimulation treatment groups improved in knee extension strength in the PFPS limb to a greater extent than the HEP alone group over the 9-week treatment period. The NMES and NMES/TENS groups improved to a greater extent than the HEP alone group in knee flexion strength in the PFPS limb. The reported pain improved over time for all treatment groups with no significant group differences. All three stimulation groups performed better on the 6-min walk test than the HEP alone group.

CONCLUSION

The findings from this study showed that all three electrical stimulation with HEP treatment groups showed greater improvement in strength compared to the HEP alone group. These findings could offer alternative forms of rehabilitation for AD military with PFPS as these treatment regimens can be easily implemented at home station or during deployment.

The Relationship of Lean Body Mass With Aging to the Development of Diabetes

CONTEXT

Older adults have the greatest burden of diabetes; however, the contribution of age-related muscle loss to its development remains unclear.

OBJECTIVE

We assessed the relationship of lean body mass with aging to incident diabetes in community-dwelling adults.

DESIGN AND SETTING

We studied participants in the Baltimore Longitudinal Study of Aging with median follow-up of 7 years (range 1-16). Cox proportional hazard models with age as the time scale were used. Time-dependent lean body mass measures were updated at each follow-up visit available.

PARTICIPANTS

Participants included 871 men and 984 women without diabetes who had  ≥ 1 assessment of body composition using dual x-ray absorptiometry.

MAIN OUTCOMES

Incident diabetes, defined as self-reported history and use of glucose-lowering medications; or fasting plasma glucose ≥ 126 mg/dL and 2-hour oral glucose tolerance test glucose ≥ 200 mg/dL either at the same visit or 2 consecutive visits.

RESULTS

The baseline mean [standard deviation] age was 58.9  [17.3] years. Men and women with a higher percentage of total lean body mass had lower fasting and 2-hour glucose levels, and less prediabetes (all P < 0.01). Among men, comparing highest versus lowest quartiles, percentage of total lean body mass (hazard ratio [HR],  0.46; 95% confidence interval, 0.22-0.97), percentage leg lean mass (HR, 0.38; 0.15-0.96), and lean-to-fat mass ratio (HR, 0.39; 0.17-0.89) were inversely associated with incident diabetes after accounting for race and attenuated after adjustment for height and weight. Conversely, absolute total lean body mass was positively associated with incident diabetes among women, with similar trends in men. No associations were observed with muscle strength or quality.

CONCLUSIONS

Relatively lower lean body mass with aging is associated with incident diabetes in men and partially related to anthropometrics, but not so in women.

Preoperative Chlorhexidine Gluconate Bathing on a Military Medical-Surgical Unit

INTRODUCTION AND SCOPE OF THE PROBLEM

Surgical site infections (SSIs) are associated with increased length of hospital stays, poor patient outcomes, and increased health care costs making prevention of SSI a high priority for the U.S. Military Health Care System. The focus of this project was to develop and pilot a preoperative antiseptic bathing regimen on an inpatient medical-surgical telemetry unit using 4% chlorhexidine gluconate (CHG), and to compare SSI rates with this new protocol to previous SSI rates on the unit.

MATERIALS AND METHODS

A literature review guided the development of the protocol and clinical question. A unit project was conducted using SSI rates from an inpatient military medical-surgical telemetry unit over 4 yr. From 2014 to 2016, 3 yr before implementing the protocol, a non-standardized CHG scrub was compared to 12 mo after implementing the standardized 4% CHG protocol in 2017 using up to four daily washings (three evenings and one morning surgery) on inpatient admissions to the unit. SSI rates were compared.

RESULTS

After implementing a 4-d preoperative bathing regimen with 4% CHG for patients scheduled for surgery, SSI rates decreased from an average rate of 0.0072 infections (7.2 infections per 1,000 surgeries) to 0.0035 infections (3.5 infections per 1,000 surgeries) in the subsequent year of data collection. Although not a statistically significant change, further analysis using a Bayesian Poisson regression model found an 84% probability the new protocol would lower SSI rate by 1 or more cases per 1,000 surgeries on this inpatient unit.

CONCLUSION

The findings suggest the proposed approach to control infection that may reduce the number of SSIs on a military medical-surgical unit, but this needs to be demonstrated through further longitudinal research on military surgical units.

Nursing's Role in Preventing and Managing Back Pain in Military Members: Proceedings of the First Back Pain Summit

This is a review of the proceedings of the first Military Nursing Back Pain Summit focusing on nursing's role in preventing and managing back pain. The purpose of the summit was to present the state of the science in back pain and to identify key gaps in research, policy, education, and treatment that could be undertaken by military nurses, nurse leaders, nurse practitioners, and nurse scientists. Several key points were highlighted during the summit: (1) back pain is multifactorial and preventable; (2) military service members have unique risk factors for developing back pain; (3) both acute and chronic back pain impact readiness and sustaining readiness is the primary mission of military medicine; (4) back pain is most effectively managed with multiple treatment approaches; (5) military culture must pivot away from an attitude of ignoring persistent pain or "toughing it out" to prevent acute back pain from becoming chronic; (6) integrating military nurses within operational units will be important for effective prevention, education, screening, and treatment within dispersed Multi-Domain Operations; and (7) early self-management is an important area for nursing research and intervention to empower service members to maintain and sustain their back health. The various presentations and panels from the meeting are summarized.

The associations of anthropometric, behavioural and sociodemographic factors with circulating concentrations of IGF-I, IGF-II, IGFBP-1, IGFBP-2 and IGFBP-3 in a pooled analysis of 16,024 men from 22 studies

Insulin-like growth factors (IGFs) and insulin-like growth factor binding proteins (IGFBPs) have been implicated in the aetiology of several cancers. To better understand whether anthropometric, behavioural and sociodemographic factors may play a role in cancer risk via IGF signalling, we examined the cross-sectional associations of these exposures with circulating concentrations of IGFs (IGF-I and IGF-II) and IGFBPs (IGFBP-1, IGFBP-2 and IGFBP-3). The Endogenous Hormones, Nutritional Biomarkers and Prostate Cancer Collaborative Group dataset includes individual participant data from 16,024 male controls (i.e. without prostate cancer) aged 22-89 years from 22 prospective studies. Geometric means of protein concentrations were estimated using analysis of variance, adjusted for relevant covariates. Older age was associated with higher concentrations of IGFBP-1 and IGFBP-2 and lower concentrations of IGF-I, IGF-II and IGFBP-3. Higher body mass index was associated with lower concentrations of IGFBP-1 and IGFBP-2. Taller height was associated with higher concentrations of IGF-I and IGFBP-3 and lower concentrations of IGFBP-1. Smokers had higher concentrations of IGFBP-1 and IGFBP-2 and lower concentrations of IGFBP-3 than nonsmokers. Higher alcohol consumption was associated with higher concentrations of IGF-II and lower concentrations of IGF-I and IGFBP-2. African Americans had lower concentrations of IGF-II, IGFBP-1, IGFBP-2 and IGFBP-3 and Hispanics had lower IGF-I, IGF-II and IGFBP-3 than non-Hispanic whites. These findings indicate that a range of anthropometric, behavioural and sociodemographic factors are associated with circulating concentrations of IGFs and IGFBPs in men, which will lead to a greater understanding of the mechanisms through which these factors influence cancer risk.

Angiotensin receptor autoantibodies as exposures that modify disease progression: Cross sectional, longitudinal and in vitro studies of prostate cancer

Circulating angiotensin type I receptor (AT1R) agonistic autoantibodies (AT1RaAbs) that bind and chronically activate the receptor have been associated with a number of diseases suggesting that while the autoantibodies are not necessarily causative they may promote disease progression. The prostate has a local renin angiotensin system. The current study examines associations between AT1RaAbs and prostate cancer (PCA), disease-free survival (DFS), overall survival (OS) and AT1RaAb effects on PCA cell phenotype. In a cross-sectional set of serum obtained from 151 men diagnosed with PCA, nonmalignant prostate disease or no disease, higher serum AT1RaAb levels were associated with PCA and non-organ confined PCA. The odds ratio for PCA was 6.3 (95% confidence interval 2.2 to 18) for a positive 1:1600 titer and 18 (95% confidence interval 6.9 to 45) at AT1RaAb levels > 1.04 μg/ml, (p < 0.0001). In a longitudinal set of pre-diagnosis samples from 109 men, DFS hazard ratios of 2.2 (95% confidence interval 1.4 to 3.5) and 1.6 (95% confidence interval 1.0 to 2.5) for most proximal to diagnosis and most distal to diagnosis samples, respectively, were found for high versus low AT1RaAb groups. Hazard ratios for OS in most proximal and distal samples were 2.4 (95% confidence interval 1.6 to 3.6) and 1.8 (95% confidence interval 1.1 to 2.8), respectively. Accelerated failure modeling of survival indicated that a 1 μg/ml increase in AT1RaAb levels was associated with a reduction of DFS and OS by 20% at the most proximal time point and by 15% at the most distal time points. Adjusting for age, did not affect the association with DFS in proximal samples but changed distal time point DFS and OS to a 10% decrease for every 1 μg/ml increase in AT1RaAb. Additional adjustments for body mass index, systolic blood pressure and prostate-specific antigen did not appreciably alter these associations. AT1RaAb treatment of PC3, DU145, and LNCaP cells significantly increased the maximal growth rate approximately 2-fold and invasiveness approximately 3-fold. Conclusions: These observations provide evidence supporting AT1RaAbs as exposures that may modify prostate cancer progression and indicate they may be predictive markers for risk stratification.

Self-Managed Strength Training for Active Duty Military With a Knee Injury: A Randomized Controlled Pilot Trial

INTRODUCTION

Knee injuries among active duty military are one of the most frequent musculoskeletal injuries and are often caused by exercise or intense physical activity or combat training. These injuries pose a threat to force readiness. Our objective was to assess feasibility (including recruitment and retention rates) of three self-managed strengthening strategies for knee injuries and determine if they resulted in improvements in lower extremity strength, function, pain, and activity compared to usual physical therapy (PT) in military members.

METHODS

A pilot study using a randomized controlled trial was conducted at three outpatient military medical treatment facilities. After baseline testing, 78 active duty military members with a knee injury were randomized to 1-4 trial arms: (1) neuromuscular electrical stimulation (NMES) applied to the quadriceps muscle; (2) graduated strength walking using a weighted vest (WALK); (3) combined NMES with strength walking (COMBO); (4) usual PT alone. All groups received usual PT. The primary outcome was the rates of change in knee extensor and flexor strength over 18 weeks. Secondary outcomes explored the rates of change in functional performance, pain, and activities of daily living scale (ADLS). The primary analysis for the endpoints used repeated measures, linear mixed-effects models. This study was approved by Institutional Review Boards at all facilities.

RESULTS

The randomized sample (N = 78) included 19 participants in the PT-only, 20 in the WALK, 19 in the NMES and 20 in the COMBO groups. At baseline, there were no group differences. Fifty of the participants completed the 18-week study. The completers and non-completers differed at baseline on injury mechanism, with more completers injured during sports (45% vs 29%), and more non-completers during military training (36% vs 18%). Also, they differed in uninjured knee extension (completers 28% weaker), and uninjured knee flexion (completers 22% weaker). Adherence for self-reported daily step logs showed that the WALK group was 15% below goal and COMBO group 6% below goal. The 300 PV muscle stimulator showed the NMES group completed 34% of recommended stimulation sessions and the COMBO group 30%.Knee extension strength in the injured knee found only the COMBO group having a statistically higher improvement compared to PT-only (Change over 18 weeks: 10.6 kg in COMBO; 2.1 kg in PT-only). For the injured knee flexion changes, only the COMBO showed significant difference from PT-only (Change over 18 weeks: 7.5 kg in COMBO; -0.2 kg in PT-only). Similarly, for the uninjured knee, only the COMBO showed significant difference from PT-only in knee extension (Change over 18 weeks: 14.7 Kg in COMBO; 2.7 kg in PT-only) and knee flexion (Change over 18 weeks: 6.5 kg in COMBO; -0.2 kg in PT-only). Overall pain improved during the study for all groups with no significant group differences. Similarly, function and ADLS significantly improved over 18 weeks, with no significant group differences.

CONCLUSIONS

Knee extensor strength improvements in the COMBO group were significantly higher compared to usual PT. Pain, functional measures, and ADLS all improved during the study with no group differences. Further research is required to confirm these findings.

Low Free Testosterone and Prostate Cancer Risk: A Collaborative Analysis of 20 Prospective Studies

BACKGROUND

Experimental and clinical evidence implicates testosterone in the aetiology of prostate cancer. Variation across the normal range of circulating free testosterone concentrations may not lead to changes in prostate biology, unless circulating concentrations are low. This may also apply to prostate cancer risk, but this has not been investigated in an epidemiological setting.

OBJECTIVE

To examine whether men with low concentrations of circulating free testosterone have a reduced risk of prostate cancer.

DESIGN, SETTING, AND PARTICIPANTS

Analysis of individual participant data from 20 prospective studies including 6933 prostate cancer cases, diagnosed on average 6.8 yr after blood collection, and 12 088 controls in the Endogenous Hormones, Nutritional Biomarkers and Prostate Cancer Collaborative Group.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Odds ratios (ORs) of incident overall prostate cancer and subtypes by stage and grade, using conditional logistic regression, based on study-specific tenths of calculated free testosterone concentration.

RESULTS AND LIMITATIONS

Men in the lowest tenth of free testosterone concentration had a lower risk of overall prostate cancer (OR=0.77, 95% confidence interval [CI] 0.69-0.86; p<0.001) compared with men with higher concentrations (2nd-10th tenths of the distribution). Heterogeneity was present by tumour grade (phet=0.01), with a lower risk of low-grade disease (OR=0.76, 95% CI 0.67-0.88) and a nonsignificantly higher risk of high-grade disease (OR=1.56, 95% CI 0.95-2.57). There was no evidence of heterogeneity by tumour stage. The observational design is a limitation.

CONCLUSIONS

Men with low circulating free testosterone may have a lower risk of overall prostate cancer; this may be due to a direct biological effect, or detection bias. Further research is needed to explore the apparent differential association by tumour grade.

PATIENT SUMMARY

In this study, we looked at circulating testosterone levels and risk of developing prostate cancer, finding that men with low testosterone had a lower risk of prostate cancer.

Immunological responsiveness of intestinal tissue explants and mucosal mononuclear cells to ex vivo stimulation

BACKGROUND

There are limited data on the immunological responsiveness of healthy intestinal tissue when it is cultured and stimulated ex vivo. Such an ex vivo model has the potential to be a valuable tool in understanding disease pathogenesis and as a preclinical tool for the assessment of candidate therapeutic agents used to treat inflammatory bowel disease (IBD).

AIM

We undertook a comprehensive study to evaluate ex vivo immunological responses of intestinal tissue and isolated mucosal mononuclear cells (MMC) to a broad range of stimuli.

METHODS

Colorectal biopsies (explants) were obtained from healthy participants by flexible sigmoidoscopy and were placed either directly into culture or digested to isolate MMC prior to placement in culture. Explants or MMC were treated with polyinosinic:polycytidylic acid (Poly IC), phytohemagglutinin (PHA), lipopolysacccharides from E Coli (LPS), anti-CD3/CD28 antibodies, or IL-1β/TNF-α for 24 h. Supernatants were assayed for 40 inflammatory biomarkers using multiplexed enzyme-linked immunosorbent assay (ELISA). The isolated MMCs were further characterized using twelve color flow cytometry.

RESULTS

Explants have greater weight adjusted constitutive expression of inflammatory biomarkers than MMCs. Biomarker responses varied as a function of immunogen and use of intact tissue or isolated cells. PHA applied to intact explants was the most effective agent in inducing biomarker changes. Stimulation induced activated and memory cellular phenotypes in both explants and MMCs.

CONCLUSIONS

The breadth and magnitude of responses from intact and enzymatically digested intestinal tissue explants stimulated with exogenous immunogens are complex and vary by tissue form and treatment. Overall, PHA stimulation of intact explants produced the most robust responses in normal human colorectal tissue. This system could potentially serve as a preliminary model of the disease state, suitable for small scale screening of new therapeutic agents prior to using IBD patient derived tissue.

Geospatial Visualization of Mobile Stroke Unit Dispatches: A Method to Optimize Service Performance

Background

Timely treatment of acute ischemic stroke is crucial to optimize outcomes. Mobile stroke units (MSU) have demonstrated ultrafast treatment compared to standard emergency care. Geospatial analysis of the distribution of MSU cases to optimize service delivery has not been reported.

Methods

We aggregated all first-year MSU dispatch occurrences and all cases classified by clinical teams as true stroke by zip code and calculated dispatch and true stroke incidence rates. We mapped dispatch and stroke cases and symbolized incidence rates by standard deviation. We confirmed visual impressions of clusters from map inspection by local Moran's I, boxplot inspection, and t test. We calculated service areas using drive times to meet dispatch and true stroke need.

Results

A significant cluster of high dispatch incident rate was confirmed around our MSU base in urban Memphis within a 5-min driving area supporting the initial placement of the MSU based on 911 activation. A significant cluster of high true stroke rate was confirmed to the east of our MSU base in suburban Memphis within a 10-min driving area. Mean incident longitude of cases of true stroke versus disregarded status was significantly eastward (p = 0.001785).

Conclusion

Our findings will facilitate determination of socio-spatial antecedents of neighborhood overutilization of 911 and MSU services in our urban neighborhoods and service delivery optimization to reach neighborhoods with true stroke burden.

Psychological and Physical Health in Military Amputees During Rehabilitation: Secondary Analysis of a Randomized Controlled Trial

BACKGROUND

Service members who have experienced combat trauma with resulting amputation are at risk for compromised quality of life postamputation. Monitoring mental and physical health in amputees returning from the war is of paramount importance. This study examined changes in physical and mental health-related quality of life in service members following traumatic unilateral, transtibial amputation (TTA) during a 12-week period of rehabilitation before and after receiving a prosthesis.

METHOD

This study is a secondary analysis from a randomized controlled trial (RCT) of military service members starting Military Amputee Rehabilitation Program (MARP) following a traumatic TTA. The study examined change in SF-36 Physical Component Summary (PCS) and Mental Component Summary (MCS) scores as two aspects of health-related quality of life. Forty-four injured service members, aged 19 to 46, were recruited into the RCT. Participants were randomized into 12 weeks of MARP plus home neuromuscular electrical stimulation therapy (n = 23) or MARP alone (N = 21) and compared at baseline, 6, and 12 weeks on: SF-36 PCS and MCS scores. Linear mixed models examined time and group differences and their interaction for the MCS and PCS scores. A multivariate mixed model tested whether MCS and PCS scores differed.

RESULTS

For the combined rehabilitation cohort, MCS did not differ over 12 weeks (p = 0.27) with scores at week 0 of M = 56.7 (SD = 11.9) and at week 12 of M = 52.7 (SD = 11.4), similar to healthy controls (age = 25-34, M = 51.0, SD = 7.6). Scores did not differ between treatment groups (p = 0.28) with no group by time interaction (p = 0.34). The MCS significantly declined over time (p = 0.05) after adjustment for covariates. PCS improved over 12 weeks (p < 0.0001) in the total rehabilitation group with scores at week 0 of M = 34.0 (SD = 8.1) to M = 41.8 (SD = 8.4) at week 12, significantly lower than healthy controls (age = 25-34, M = 54.1, SD = 6.6). Scores did not differ between treatment groups (p = 0.89), and there was no group by time interaction (p = 0.34). An interaction between the PCS and MCS was observed such that the PCS improved over time, whereas the MCS did not significantly change (p = 0.0005).

DISCUSSION

War-injured transtibial amputees are at risk for compromised quality of life during rehabilitation. Self-perceived physical health improved as might be expected from rehabilitation. Self-perceived mental health did not. During rehabilitation, physical healing, psychological adjustment, and lifestyle adaptation are occurring simultaneously. However, more attention may need to be directed toward mental health during rehabilitation.

Abstract TP357: BP Management on the Mobile Stroke Unit for Ultra-Early Treatment of ICH and Acute Ischemic Stroke

Background: Lowering of blood pressure (BP) is discouraged in current ASA guidelines for emergency medical service (EMS) personnel. However, ultra-early treatment with IVtPA and BP lowering in ICH are possible on mobile stroke units (MSU). We examined the effectiveness and safety of two antihypertensive agents for MSU treatment.

Methods: Consecutive MSU patients were treated with target ICH BP parameters less than 140/90, and IVtPA BP parameters by current guidelines. BP was measured by noninvasive oscillometric cuff, and cycled every 5 minutes per EMS MSU protocol. Available agents were labetalol IV 10-20mg and/or nicardipine double-strength premix infusion started at 5mg/hour and titrated. Preference in usage, and effect were recorded and analyzed for the first year of MSU operation.

Results: During 168 service days, 127 acute stroke patients were transported (68±16, range 23-96 years; 58% women; 65% African American, 34% White; 1% Hispanic). Fifteen (12%) had hemorrhage on CT (1 aneurysmal SAH, 1 SDH, 1 subacute AIS with HT-2; 12 HTN ICH [median ICH score 2, IQR 1-3] of which 1 had a positive spot sign on CTA). AIS cases (n=100) had median NIHSS 9 (IQR 7-17); 38% were treated with IVtPA at a median 13 (IQR 11-16) minutes from scene arrival, one of these by IO route, with 1 angioedema and 0 sICH. Labetalol was used for 9 patients, with all but one (89%) requiring the addition of nicardipine infusion. In 24 patients nicardipine was the first agent selected, with 100% achieving target BP control prior to hospital arrival.

Conclusions: MSU use of nicardipine double-strength premix infusions provides rapid, reliable, and safe BP control. When time is of the essence, elimination of labetalol, in favor of a dihydropyridine calcium channel blocker infusion may provide the most rapid achievement of prescribed BP parameters.

Abstract WP215: Geospatial Visualization of Mobile Stroke Unit Dispatches: A Method to Optimize Service Performance

Background: Understanding geospatial regional stroke burden and emergency medical services (EMS) response locations may benefit attainment and distribution of prehospital resources, enabling rapid diagnosis and treatment. We sought to understand the spatial distribution of all Mobile Stroke Unit (MSU) dispatches and diagnosed strokes during the first year of operation.

Methods: All MSU dispatched cases from July 2016 to July 2017 were assembled and aggregated into groups based on stroke diagnosis status. The raw count of incidents was aggregated by zip code, normalized to population, and geocoded. The resulting incidence rate was symbolized by standard deviation and mapped by zip code for inspection. Five- and ten-minute drive time service areas were defined around our MSU base.

Results: A total of 420 dispatches for suspected stroke occurred, of which 394 were able to be geocoded. On the initial analysis of all 394 cases, a five-minute service area was sufficient to rapidly reach areas with high rates of suspected stroke burden (> 1.5 SD) (figure 1). However, repeating the analysis on 123 cases diagnosed as true strokes redefined the areas that were strongly positive for high stroke burden requiring a ten-minute service area from our MSU base (figure 2).

Conclusions: Use of geospatial findings helps plan EMS and MSU dispatch to high burden regional pockets of stroke, and may assist in improving dispatch scripting for 911 calls.

Circulating sex hormones in relation to anthropometric, sociodemographic and behavioural factors in an international dataset of 12,300 men

INTRODUCTION

Sex hormones have been implicated in the etiology of a number of diseases. To better understand disease etiology and the mechanisms of disease-risk factor associations, this analysis aimed to investigate the associations of anthropometric, sociodemographic and behavioural factors with a range of circulating sex hormones and sex hormone-binding globulin.

METHODS

Statistical analyses of individual participant data from 12,330 male controls aged 25-85 years from 25 studies involved in the Endogenous Hormones Nutritional Biomarkers and Prostate Cancer Collaborative Group. Analysis of variance was used to estimate geometric means adjusted for study and relevant covariates.

RESULTS

Older age was associated with higher concentrations of sex hormone-binding globulin and dihydrotestosterone and lower concentrations of dehydroepiandrosterone sulfate, free testosterone, androstenedione, androstanediol glucuronide and free estradiol. Higher body mass index was associated with higher concentrations of free estradiol, androstanediol glucuronide, estradiol and estrone and lower concentrations of dihydrotestosterone, testosterone, sex hormone-binding globulin, free testosterone, androstenedione and dehydroepiandrosterone sulfate. Taller height was associated with lower concentrations of androstenedione, testosterone, free testosterone and sex hormone-binding globulin and higher concentrations of androstanediol glucuronide. Current smoking was associated with higher concentrations of androstenedione, sex hormone-binding globulin and testosterone. Alcohol consumption was associated with higher concentrations of dehydroepiandrosterone sulfate, androstenedione and androstanediol glucuronide. East Asians had lower concentrations of androstanediol glucuronide and African Americans had higher concentrations of estrogens. Education and marital status were modestly associated with a small number of hormones.

CONCLUSION

Circulating sex hormones in men are strongly associated with age and body mass index, and to a lesser extent with smoking status and alcohol consumption.

Telomere Shortening, Inflammatory Cytokines, and Anti-Cytomegalovirus Antibody Follow Distinct Age-Associated Trajectories in Humans

A number of biological parameters have been cited as hallmarks of immune aging. However, it is not clear whether these multiple biological changes are the result of common underlying aging processes and follow correlated trajectories, or whether the patterns of change for multiple parameters vary across individuals and reflect heterogeneity in the aging process. Here, we have studied parameters of immune system aging through longitudinal analysis of telomere length, inflammatory cytokines, and antibody titer to cytomegalovirus (CMV) in 465 subjects ranging in age from 21 to 88 years at the first visit, with an average of 13 years (7-19 years) follow-up. We observed a highly variable rate of change in telomere length of PBMCs with a relatively slow average rate of telomere shortening (-16 bp/year). Similarly, there were significant increases with age in vivo in three inflammation-related cytokines (interferon gamma, IL-6, and IL-10) and in anti-CMV IgG titer, which varied widely across individuals as well. We further observed positive correlative changes among different inflammatory cytokines. However, we did not find significant correlations among the rate of changes in telomere length, inflammatory cytokines, and anti-CMV IgG titers. Our findings thus reveal that age-related trajectories of telomere attrition, elevated circulating inflammatory cytokines, and anti-CMV IgG are independent and that aging individuals do not show a uniform pattern of change in these variables. Immune aging processes are complex and vary across individuals, and the use of multiple biomarkers is essential to evaluation of biological aging of the immune system.

Health-related quality of life in active duty military: A secondary data analysis of two randomized controlled trials

BACKGROUND

Military service members with lower extremity injuries are at risk for compromised health-related quality of life during rehabilitation.

PURPOSE

The purpose of this secondary data analysis was to examine changes in self-perceived physical and mental health in two clinical trials of military service members during rehabilitation for a lower extremity injury.

METHODS

This study is a secondary analysis of existing data from two cohorts of active duty military service members with lower extremity injuries as they participated in separate randomized controlled trials.

DISCUSSION

A similar pattern for both physical and mental health was observed in both groups of participants. Perceptions of physical health improved significantly in both studies, whereas mental health perceptions may or may not have declined.

CONCLUSION

Increased attention to mental health may be important during rehabilitation after major and minor lower extremity injuries. Although perceptions of physical health improve, corresponding changes may not occur in mental health perceptions.

Abstract WP64: City-wide Stroke Team in the U.S. Delivers the Highest Intravenous Thrombolysis Treatment Rate

Background: An increasing shortage of vascular neurologists forced an academic provider to find a city-wide solution to offer 24x7 access to intravenous thrombolysis (IVT) across independent and competing health care systems in the area. We sought to prospectively evaluate the annual IVT treatment delivery in our population and compare it to leading stroke centers worldwide.

Methods: The largest single ER system and 3 other independent hospital providers in the area agreed to work with a single practice plan vascular neurology team (catchment area of 1,344,127 individuals). All acute ischemic stroke patients that were treated with IVT across all primary or tertiary care centers in our area were prospectively documented over a 12-month period (January-December 2015). A literature search was performed using narrative review methodology to document similar population-based treatment rates across leading stroke centers in North America, Europe and Australasia.

Results: A total of 552 patients received IVT with tissue plasminogen activator (tPA) in 2015. Single ER system delivered 433 IV tPA treatments and 119 more patients were treated in the remaining hospitals. The annual tPA treatment rate was 41 per 100.000 individuals (95%CI: 38-44) favorably comparable to published annual treatment rates from leading international stroke centers (Table, 1998 thru 2015).

Conclusions: A city-wide vascular neurology team can attend to patient populations across competing health care systems in the U.S. and deliver IVT at volumes and rates above those reported by leading treatment centers worldwide. Communities with competing systems can improve tPA delivery by sharing vascular neurology resources.

Prostate-specific antigen patterns in US and European populations: comparison of six diverse cohorts

OBJECTIVE

To determine whether there are differences in prostate-specific antigen (PSA) levels at diagnosis or changes in PSA levels between US and European populations of men with and without prostate cancer (PCa).

SUBJECTS AND METHODS

We analysed repeated measures of PSA from six clinically and geographically diverse cohorts of men: two cohorts with PSA-detected PCa, two cohorts with clinically detected PCa and two cohorts without PCa. Using multilevel models, average PSA at diagnosis and PSA change over time were compared among study populations.

RESULTS

The annual percentage PSA change of 4-5% was similar between men without cancer and men with PSA-detected cancer. PSA at diagnosis was 1.7 ng/mL lower in a US cohort of men with PSA-detected PCa (95% confidence interval 1.3-2.0 ng/mL), compared with a UK cohort of men with PSA-detected PCa, but there was no evidence of a different rate of PSA change between these populations.

CONCLUSION

We found that PSA changes over time are similar in UK and US men diagnosed through PSA testing and even in men without PCa. Further development of PSA models to monitor men on active surveillance should be undertaken in order to take advantage of these similarities. We found no evidence that guidelines for using PSA to monitor men cannot be passed between US and European studies.

Selenium and Prostate Cancer: Analysis of Individual Participant Data From Fifteen Prospective Studies

BACKGROUND

Some observational studies suggest that a higher selenium status is associated with a lower risk of prostate cancer but have been generally too small to provide precise estimates of associations, particularly by disease stage and grade.

METHODS

Collaborating investigators from 15 prospective studies provided individual-participant records (from predominantly men of white European ancestry) on blood or toenail selenium concentrations and prostate cancer risk. Odds ratios of prostate cancer by selenium concentration were estimated using multivariable-adjusted conditional logistic regression. All statistical tests were two-sided.

RESULTS

Blood selenium was not associated with the risk of total prostate cancer (multivariable-adjusted odds ratio [OR] per 80 percentile increase = 1.01, 95% confidence interval [CI] = 0.83 to 1.23, based on 4527 case patients and 6021 control subjects). However, there was heterogeneity by disease aggressiveness (ie, advanced stage and/or prostate cancer death, Pheterogeneity = .01), with high blood selenium associated with a lower risk of aggressive disease (OR = 0.43, 95% CI = 0.21 to 0.87) but not with nonaggressive disease. Nail selenium was inversely associated with total prostate cancer (OR = 0.29, 95% CI = 0.22 to 0.40, Ptrend < .001, based on 1970 case patients and 2086 control subjects), including both nonaggressive (OR = 0.33, 95% CI = 0.22 to 0.50) and aggressive disease (OR = 0.18, 95% CI = 0.11 to 0.31, Pheterogeneity = .08).

CONCLUSIONS

Nail, but not blood, selenium concentration is inversely associated with risk of total prostate cancer, possibly because nails are a more reliable marker of long-term selenium exposure. Both blood and nail selenium concentrations are associated with a reduced risk of aggressive disease, which warrants further investigation.

FABS

Background and Purpose—

A large number of patients with symptoms of acute cerebral ischemia are stroke mimics (SMs). In this study, we sought to develop a scoring system (FABS) for screening and stratifying SM from acute cerebral ischemia and to identify patients who may require magnetic resonance imaging to confirm or refute a diagnosis of stroke in the emergency setting.

Methods—

We designed a scoring system: FABS (6 variables with 1 point for each variable present): absence of Facial droop, negative history of Atrial fibrillation, Age <50 years, systolic Blood pressure <150 mm Hg at presentation, history of Seizures, and isolated Sensory symptoms without weakness at presentation. We evaluated consecutive patients with symptoms of acute cerebral ischemia and a negative head computed tomography for any acute finding within 4.5 hours after symptom onset in 2 tertiary care stroke centers for validation of FABS.

Results—

A total of 784 patients (41% SMs) were evaluated. Receiver operating characteristic curve (C statistic, 0.95; 95% confidence interval [CI], 0.93–0.98) indicated that FABS≥3 could identify patients with SM with 90% sensitivity (95% CI, 86%–93%) and 91% specificity (95% CI, 88%–93%). The negative predictive value and positive predictive value were 93% (95% CI, 90%–95%) and 87% (95% CI, 83%–91%), respectively.

Conclusions—

FABS seems to be reliable in stratifying SM from acute cerebral ischemia cases among patients in whom the head computed tomography was negative for any acute findings. It can help clinicians consider advanced imaging for further diagnosis.

Changes in blood lymphocyte numbers with age in vivo and their association with the levels of cytokines/cytokine receptors

Background

Alterations in the number and composition of lymphocytes and their subsets in blood are considered a hallmark of immune system aging. However, it is unknown whether the rates of change of lymphocytes are stable or change with age, or whether the inter-individual variations of lymphocyte composition are stable over time or undergo different rates of change at different ages. Here, we report a longitudinal analysis of T- and B-cells and their subsets, and NK cells in the blood of 165 subjects aged from 24 to 90 years, with each subject assessed at baseline and an average of 5.6 years follow-up.

Results

The rates of change of T-(CD4⁺ and CD8⁺) and B-cells, and NK cells were relative stable throughout the adult life. A great degree of individual variations in numbers of lymphocytes and their subsets and in the rates of their changes with age was observed. Among them, CD4⁺ T cells exhibited the highest degree of individual variation followed by NK cells, CD8⁺ T cells, and B cells. Different types of lymphocytes had distinct trends in their rates of change which did not appear to be influenced by CMV infection. Finally, the rates of CD4⁺, CD8⁺ T cells, naive CD4⁺ and naïve CD8⁺ T cells were closely positively correlated.

Conclusion

Our findings provide evidence that the age-associated changes in circulating lymphocytes were at relative stable rates in vivo in a highly individualized manner and the levels of selected cytokines/cytokine receptors in serum might influence these age-associated changes of lymphocytes in circulation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12979-016-0079-7) contains supplementary material, which is available to authorized users.

Ankle proprioceptive acuity is associated with objective as well as self-report measures of balance, mobility, and physical function

Ankle proprioceptive information is integrated by the central nervous system to generate and modulate muscle contractions for maintaining standing balance. This study evaluated the association of ankle joint proprioception with objective and self-report measures of balance, mobility, and physical function across the adult life span. Seven hundred and ninety participants (age range 24-97 years, 362 women) who completed ankle proprioception assessment between 2010 and 2014 were included in the present study from the population-based cohort of the Baltimore Longitudinal Study of Aging (BLSA), USA. Outcome measures included ankle joint proprioception measured as threshold for perception of passive movement (TPPM); single leg stance time; perceived difficulty for standing balance; usual, fastest, and narrow-path gait speed; walking index; short physical performance battery score; and self-reported activity restriction due to fear of falling. Descriptive variables included age, sex, body mass index, education, strength, and cognition. Analyses of covariance (ANCOVA) in general linear model (GLM) or multinomial logistic regression analyses were performed, as appropriate, to test the hypothesis that balance, mobility, and physical function were significantly different according to TPPM quintiles even after adjusting for relevant covariates. Those with TPPM >2.2° consistently demonstrated poor balance, mobility, and physical function. However, with increase in challenge (single leg stance, fastest walking speed, and SPPB), TPPM >1.4° was associated with significantly worse performance. In conclusion, ankle proprioceptive acuity has an overall graded relationship with objective and self-report measures of balance, mobility, and physical function. However, the cutoff proprioceptive acuity associated with substantial decline or inability to perform could depend on the challenge induced.

A Meta-analysis of Individual Participant Data Reveals an Association between Circulating Levels of IGF-I and Prostate Cancer Risk

The role of insulin-like growth factors (IGF) in prostate cancer development is not fully understood. To investigate the association between circulating concentrations of IGFs (IGF-I, IGF-II, IGFBP-1, IGFBP-2, and IGFBP-3) and prostate cancer risk, we pooled individual participant data from 17 prospective and two cross-sectional studies, including up to 10,554 prostate cancer cases and 13,618 control participants. Conditional logistic regression was used to estimate the ORs for prostate cancer based on the study-specific fifth of each analyte. Overall, IGF-I, IGF-II, IGFBP-2, and IGFBP-3 concentrations were positively associated with prostate cancer risk (Ptrend all ≤ 0.005), and IGFBP-1 was inversely associated weakly with risk (Ptrend = 0.05). However, heterogeneity between the prospective and cross-sectional studies was evident (Pheterogeneity = 0.03), unless the analyses were restricted to prospective studies (with the exception of IGF-II, Pheterogeneity = 0.02). For prospective studies, the OR for men in the highest versus the lowest fifth of each analyte was 1.29 (95% confidence interval, 1.16-1.43) for IGF-I, 0.81 (0.68-0.96) for IGFBP-1, and 1.25 (1.12-1.40) for IGFBP-3. These associations did not differ significantly by time-to-diagnosis or tumor stage or grade. After mutual adjustment for each of the other analytes, only IGF-I remained associated with risk. Our collaborative study represents the largest pooled analysis of the relationship between prostate cancer risk and circulating concentrations of IGF-I, providing strong evidence that IGF-I is highly likely to be involved in prostate cancer development. Cancer Res; 76(8); 2288-300. ©2016 AACR.

Aging-Related Considerations When Evaluating the Forced Expiratory Volume in 1 Second (FEV1) Over Time

BACKGROUND

Forced expiratory volume in 1 second (FEV1) over time is commonly expressed in liters and percent predicted (%Pred), or alternatively in L/m(3) and Z-scores-which approach is more clinically meaningful has not been evaluated. Because it uniquely accounts for the effect of aging on FEV1 and spirometric performance, we hypothesized that the Z-score approach is more clinically meaningful, based on associations between cardiopulmonary predictors and FEV1 over time.

METHODS

Using linear mixed-effects models and data from the Baltimore Longitudinal Study on Aging, including 501 white participants aged 40-95 who had completed at least three longitudinal spirometric assessments, we evaluated the associations between cardiopulmonary predictors (obesity, smoking status, hypertension, chronic bronchitis, diabetes mellitus, and myocardial infarction) and FEV1 over time, in liters, %Pred, L/m(3), and Z-scores.

RESULTS

Mean baseline values for FEV1 were 3.240L, 96.4%Pred, 0.621L/m(3), and -0.239 as a Z-score (40.6th percentile). The annual decline in FEV1 was 0.040L, 0.234 %Pred, 0.007L/m(3), and 0.008 Z-score units. Baseline age was associated with FEV1 over time in liters and L/m(3) (p < .001), and included a time interaction for %Pred (p < .001), but was not associated with Z-scores (p = .933). The associations of cardiopulmonary predictors with FEV1 over time were all significant when using Z-scores (p < .05), but varied for other methods of expressing FEV1.

CONCLUSION

A Z-score approach is more clinically meaningful when evaluating FEV1 over time, as it accounted for the effect of aging and was more frequently associated with multiple cardiopulmonary predictors.

Telomere Length as an Indicator of the Robustness of B- and T-Cell Response to Influenza in Older Adults

BACKGROUND

Telomeres provide a key mechanism for protecting the integrity of chromosomes and their attrition after cell division and during aging are evident in lymphocytes. However, the significance of telomere shortening in age-associated decline of immune function is unknown.

METHODS

We selected 22 HLA-A2-positive healthy older adults who have relatively short or long telomere lengths to compare their antibody response against the influenza vaccine, and their CD8(+) T-cell response against an influenza antigen.

RESULTS

B cells from individuals with a robust antibody response to the influenza vaccine had significantly longer telomeres than those with a poor antibody response. Monocyte-derived antigen-presenting cells of both short and long telomere groups induced similar expansions of influenza M1-specific CD8(+) T cells. Vaccination did not increase M1-specific CD8(+) T cells in blood, but M1-specific CD8(+) T cells from the long telomere group exhibited significantly greater expansion in vitro than those from the short telomere group. Finally, M1-specific CD8(+) T cells that underwent more expansions had significantly longer telomeres than cells with fewer divisions.

CONCLUSIONS

Telomere length is positively associated with a robust lymphocyte response, and telomere attrition may contribute to the age-associated decline of adaptive immunity.

TCRβ repertoire of CD4+ and CD8+ T cells is distinct in richness, distribution, and CDR3 amino acid composition

The TCR repertoire serves as a reservoir of TCRs for recognizing all potential pathogens. Two major types of T cells, CD4(+) and CD8(+), that use the same genetic elements and process to generate a functional TCR differ in their recognition of peptide bound to MHC class II and I, respectively. However, it is currently unclear to what extent the TCR repertoire of CD4(+) and CD8(+) T cells is different. Here, we report a comparative analysis of the TCRβ repertoires of CD4(+) and CD8(+) T cells by use of a 5' rapid amplification of cDNA ends-PCR-sequencing method. We found that TCRβ richness of CD4(+) T cells ranges from 1.2 to 9.8 × 10(4) and is approximately 5 times greater, on average, than that of CD8(+) T cells in each study subject. Furthermore, there was little overlap in TCRβ sequences between CD4(+) (0.3%) and CD8(+) (1.3%) T cells. Further analysis showed that CD4(+) and CD8(+) T cells exhibited distinct preferences for certain amino acids in the CDR3, and this was confirmed further by a support vector machine classifier, suggesting that there are distinct and discernible differences between TCRβ CDR3 in CD4(+) and CD8(+) T cells. Finally, we identified 5-12% of the unique TCRβs that share an identical CDR3 with different variable genes. Together, our findings reveal the distinct features of the TCRβ repertoire between CD4(+) and CD8(+) T cells and could potentially be used to evaluate the competency of T cell immunity.

Detection of a novel, integrative aging process suggests complex physiological integration

Many studies of aging examine biomarkers one at a time, but complex systems theory and network theory suggest that interpretations of individual markers may be context-dependent. Here, we attempted to detect underlying processes governing the levels of many biomarkers simultaneously by applying principal components analysis to 43 common clinical biomarkers measured longitudinally in 3694 humans from three longitudinal cohort studies on two continents (Women's Health and Aging I & II, InCHIANTI, and the Baltimore Longitudinal Study on Aging). The first axis was associated with anemia, inflammation, and low levels of calcium and albumin. The axis structure was precisely reproduced in all three populations and in all demographic sub-populations (by sex, race, etc.); we call the process represented by the axis "integrated albunemia." Integrated albunemia increases and accelerates with age in all populations, and predicts mortality and frailty--but not chronic disease--even after controlling for age. This suggests a role in the aging process, though causality is not yet clear. Integrated albunemia behaves more stably across populations than its component biomarkers, and thus appears to represent a higher-order physiological process emerging from the structure of underlying regulatory networks. If this is correct, detection of this process has substantial implications for physiological organization more generally.

Age-associated telomere attrition of lymphocytes in vivo is co-ordinated with changes in telomerase activity, composition of lymphocyte subsets and health conditions

Telomeres are essential in maintaining chromosome integrity and in controlling cellular replication. Attrition of telomere length in peripheral blood mononuclear cells (PBMCs) with age is well documented from cross-sectional studies. But the actual in vivo changes in telomere lengths and its relationship with the contributing factors within the individuals with age have not been fully addressed. In the present paper, we report a longitudinal analysis of telomere length in the PBMCs, lymphocytes and monocytes of 216 human subjects aged from 20-90 years assessed at 0-, 5- and 12-year follow-up. For the 5- and 12-year follow-up, telomere length in the PBMCs decreased in 34% and 46%, exhibited no detectable change in 56% and 47% and increased in 10% and 7% of the subjects respectively. The rate of telomere change was distinct for T-cells, B-cells and monocytes for any given subject. Telomerase activity declined with age in the resting T-cells and B-cells and the activated T-cells. Finally, a significant portion of telomere attrition in T-cells with age was explained by a decline in the telomerase activity, decreased naïve cells and the change in physiological conditions such as elevated blood glucose and interleukin (IL)-6 levels. These findings show that changes in the telomere length of the PBMCs with age in vivo occur at different rates in different individuals and cell types and reveal that changes in the telomere length in the T-cells with age is influenced by the telomerase activity, naïve T-cell percentage and changes in health conditions.

Hyperglycemia predicts persistently lower muscle strength with aging

OBJECTIVE

Persons with diabetes have accelerated muscle loss compared with their counterparts. The relationship of hyperglycemia per se to declines in muscle function has not been explored yet has implications for developing appropriate intervention strategies to prevent muscle loss.

RESEARCH DESIGN AND METHODS

We examined 984 participants aged 25-96 years in the Baltimore Longitudinal Study of Aging (2003-2011) with HbA1c, knee extensor strength (isokinetic dynamometer), and lean body mass (DEXA) measured at baseline. Participants had repeated measurements up to 7.5 years later. Muscle quality was defined as knee extensor strength/leg lean mass. Participants were categorized by HbA1c quartile (<5.5, 5.5-5.79, 5.8-6.09, and ≥6.1% or <37, 37-40, 40-43, and ≥43 mmol/mol). Mixed-effects regression models were used to examine the regression of muscle outcomes on HbA1c.

RESULTS

Muscle strength and quality were significantly lower across HbA1c quartiles (both P < 0.001), without differences in muscle mass at baseline. Comparing highest versus lowest HbA1c quartiles and adjusting for age, race, sex, weight, and height, strength was significantly lower (-4.70 ± 2.30 N · m; P value trend = 0.02) and results were unchanged after adjustment for physical activity (P value trend = 0.045) but of borderline significance after additional adjustment for peripheral neuropathy (P value trend = 0.05). Adjusting for demographics, muscle quality was significantly lower (-0.32 ± 0.15 N · m/kg; P value trend = 0.02) in the highest versus lowest HbA1c quartiles, but differences were attenuated after adjusting for weight and height (-0.25 ± 0.15 N · m/kg; P value trend = 0.07). Muscle mass measures were similar across HbA1c quartiles.

CONCLUSIONS

Hyperglycemia is associated with persistently lower muscle strength with aging, but this effect may be mediated, at least in part, by peripheral neuropathy. Future studies should explore if better glycemic control can preserve muscle function in diabetes.

Cost effectiveness of two army physical fitness programs

Repeated failure in the Army Physical Fitness Test (APFT) is associated with lower fitness level, premature discharge, and significant career disruption, at high economic and health costs to the individual soldier and the U.S. Army. We used cost-effectiveness analysis to estimate the health and economic implications of two exercise interventions for Army National Guard (ARNG) soldiers who had failed the APFT, a traditional remediation program and a new pedometer-based program called Fitness for Life, involving individual counseling and follow-up telephone calls. Effectiveness of the interventions was analyzed in terms of APFT pass rates and calculated 10-year coronary heart disease risk. Costs were calculated based on tracking of resources used in the programs. APFT pass rates were 54.3% and 47.9%, respectively, for traditional and Fitness for Life programs, p = not significant. Neither program affected 10-year coronary heart disease risk. For assumed APFT pass rates up to 40% without any formal remediation, both the traditional remediation program and the ARNG Fitness for Life intervention had cost savings without significant group differences. Depending on the ARNG unit and personnel preference, although the Fitness for Life Program was more expensive and thus less cost-effective, either program could be cost-effective and of benefit to the military.

Association of hearing impairment with brain volume changes in older adults

Hearing impairment in older adults is independently associated in longitudinal studies with accelerated cognitive decline and incident dementia, and in cross-sectional studies, with reduced volumes in the auditory cortex. Whether peripheral hearing impairment is associated with accelerated rates of brain atrophy is unclear. We analyzed brain volume measurements from magnetic resonance brain scans of individuals with normal hearing versus hearing impairment (speech-frequency pure tone average>25 dB) followed in the neuroimaging substudy of the Baltimore Longitudinal Study of Aging for a mean of 6.4 years after the baseline scan (n=126, age 56-86 years). Brain volume measurements were performed with semi-automated region-of-interest (ROI) algorithms, and brain volume trajectories were analyzed with mixed-effect regression models adjusted for demographic and cardiovascular factors. We found that individuals with hearing impairment (n=51) compared to those with normal hearing (n=75) had accelerated volume declines in whole brain and regional volumes in the right temporal lobe (superior, middle, and inferior temporal gyri, parahippocampus, p<.05). These results were robust to adjustment for multiple confounders and were consistent with voxel-based analyses, which also implicated right greater than left temporal regions. These findings demonstrate that peripheral hearing impairment is independently associated with accelerated brain atrophy in whole brain and regional volumes concentrated in the right temporal lobe. Further studies investigating the mechanistic basis of the observed associations are needed.

Difference in muscle quality over the adult life span and biological correlates in the Baltimore Longitudinal Study of Aging

OBJECTIVES

To examine differences in a proxy measure of muscle quality across the adult life span and explore potential mechanisms of muscle quality change through identification of cross-sectional correlates of muscle quality.

DESIGN

Cross-sectional study.

SETTING

Baltimore Longitudinal Study of Aging.

PARTICIPANTS

Seven hundred eighty-six individuals with a mean age of 66.3 (range 26-96) (N = 786). A sensitivity analysis was conducted in a subset of participants matched according to sex, muscle mass, and body size.

MEASUREMENTS

Muscle quality was operationalized as the ratio of knee-extension strength (isokinetic dynamometry) to thigh muscle cross-sectional area (computed tomography). Differences in muscle strength, muscle area, and muscle quality ratio with age were evaluated, and the association between the muscle quality ratio and measures reflecting domains of cognitive function, motor control, peripheral nerve function, adiposity, glucose homeostasis, and inflammation were assessed through multivariate regression analyses.

RESULTS

A linear relationship between age and muscle quality ratio was observed, suggesting a gradual decline in muscle quality over the adult life course. Associations were observed between muscle quality ratio and measures of adiposity, as well as peroneal nerve motor conduction velocity, finger tapping speed, and memory performance (P < .01). The association between muscle quality ratio and nerve conduction velocity was maintained after adjustment for anthropometric measurements (P < .05).

CONCLUSION

Muscle quality declines progressively with age over the adult life span and is affected by obesity and neurological factors. Studies are needed to clarify the mechanisms of these associations and their implications for functional outcomes.