Utility of targeted gene sequencing to differentiate myeloid malignancies from other cytopenic conditions

The National Heart, Lung, and Blood Institute-funded National MDS Natural History Study (NCT02775383) is a prospective cohort study enrolling patients with cytopenia with suspected myelodysplastic syndromes (MDS) to evaluate factors associated with disease. Here, we sequenced 53 genes in bone marrow samples harvested from 1298 patients diagnosed with myeloid malignancy, including MDS and non-MDS myeloid malignancy or alternative marrow conditions with cytopenia based on concordance between independent histopathologic reviews (local, centralized, and tertiary to adjudicate disagreements when needed). We developed a novel 2-stage diagnostic classifier based on mutational profiles in 18 of 53 sequenced genes that were sufficient to best predict a diagnosis of myeloid malignancy and among those with a predicted myeloid malignancy, predict whether they had MDS. The classifier achieved a positive predictive value (PPV) of 0.84 and negative predictive value (NPV) of 0.8 with an area under the receiver operating characteristic curve (AUROC) of 0.85 when classifying patients as having myeloid vs no myeloid malignancy based on variant allele frequencies (VAFs) in 17 genes and a PPV of 0.71 and NPV of 0.64 with an AUROC of 0.73 when classifying patients as having MDS vs non-MDS malignancy based on VAFs in 10 genes. We next assessed how this approach could complement histopathology to improve diagnostic accuracy. For 99 of 139 (71%) patients (PPV of 0.83 and NPV of 0.65) with local and centralized histopathologic disagreement in myeloid vs no myeloid malignancy, the classifier-predicted diagnosis agreed with the tertiary pathology review (considered the internal gold standard).

Changes in Seizure Frequency and Antiepileptic Therapy during Pregnancy

BACKGROUND

Among women with epilepsy, studies regarding changes in seizure frequency during pregnancy have been limited by the lack of an appropriate nonpregnant comparator group to provide data on the natural course of seizure frequency in both groups.

METHODS

In this prospective, observational, multicenter cohort study, we compared the frequency of seizures during pregnancy through the peripartum period (the first 6 weeks after birth) (epoch 1) with the frequency during the postpartum period (the following 7.5 months after pregnancy) (epoch 2). Nonpregnant women with epilepsy were enrolled as controls and had similar follow-up during an 18-month period. The primary outcome was the percentage of women who had a higher frequency of seizures that impaired awareness during epoch 1 than during epoch 2. We also compared changes in the doses of antiepileptic drugs that were administered in the two groups during the first 9 months of epoch 1.

RESULTS

We enrolled 351 pregnant women and 109 controls with epilepsy. Among the 299 pregnant women and 93 controls who had a history of seizures that impaired awareness and who had available data for the two epochs, seizure frequency was higher during epoch 1 than during epoch 2 in 70 pregnant women (23%) and in 23 controls (25%) (odds ratio, 0.93; 95% confidence interval [CI], 0.54 to 1.60). During pregnancy, the dose of an antiepileptic drug was changed at least once in 74% of pregnant women and in 31% of controls (odds ratio, 6.36; 95% CI, 3.82 to 10.59).

CONCLUSIONS

Among women with epilepsy, the percentage who had a higher incidence of seizures during pregnancy than during the postpartum period was similar to that in women who were not pregnant during the corresponding epochs. Changes in doses of antiepileptic drugs occurred more frequently in pregnant women than in nonpregnant women during similar time periods. (Funded by the National Institutes of Health; MONEAD ClinicalTrials.gov number, NCT01730170.).

Structural and Volumetric Brain MRI Findings in Mild Traumatic Brain Injury

BACKGROUND AND PURPOSE

Routine MR imaging findings are frequently normal following mild traumatic brain injury and have a limited role in diagnosis and management. Advanced MR imaging can assist in detecting pathology and prognostication but is not readily available outside research settings. However, 3D isotropic sequences with ∼1-mm³ voxel size are available on community MR imaging scanners. Using such sequences, we compared radiologists' findings and quantified regional brain volumes between a mild traumatic brain injury cohort and non-brain-injured controls to describe structural imaging findings associated with mild traumatic brain injury.

MATERIALS AND METHODS

Seventy-one military personnel with persistent symptoms and 75 controls underwent 3T MR imaging. Three neuroradiologists interpreted the scans using common data elements. FreeSurfer was used to quantify regional gray and white matter volumes.

RESULTS

WM hyperintensities were seen in 81% of the brain-injured group versus 60% of healthy controls. The odds of ≥1 WM hyperintensity in the brain-injured group was about 3.5 times the odds for healthy controls (95% CI, 1.58-7.72; P = .002) after adjustment for age. A frontal lobe-only distribution of WM hyperintensities was more commonly seen in the mild traumatic brain injury cohort. Furthermore, 7 gray matter, 1 white matter, and 2 subcortical gray matter regions demonstrated decreased volumes in the brain-injured group after multiple-comparison correction. The mild traumatic brain injury cohort showed regional parenchymal volume loss.

CONCLUSIONS

White matter findings are nonspecific and therefore a clinical challenge. Our results suggest that prior trauma should be considered in the differential diagnosis of multifocal white matter abnormalities with a clinical history of mild traumatic brain injury, particularly when a frontal predilection is observed.

A composite outcome for mild traumatic brain injury in trials of hyperbaric oxygen

INTRODUCTION

Global outcomes can strengthen inferences from clinical trials. We evaluate global outcomes for persistent post-concussive symptoms (PCS) after mild traumatic brain injury (mTBI) in two clinical trials of hyperbaric oxygen (HBO2) in United States service members.

METHODS

During study design, outcomes of symptom, cognitive, and functional impairments planned for a trial of HBO2 for PCS (HOPPS) were weighted and grouped into different domains to formulate the composite outcome total score. The composite outcome was compared between the intervention groups in HOPPS and those in a subsequent HBO2 trial (BIMA) for validation. Additionally, two post hoc global outcome measures were explored, including one composed of components that demonstrated favorable characteristics in both studies and another via components used in another TBI randomized trial (COBRIT).

RESULTS

In total, 143 active-duty or veteran military personnel were randomized across the two studies. Composite total scores improved from baseline for HBO2 (mean ± SD -2.9±9.0) and sham (-2.9±6.6) groups in HOPPS but did not differ significantly between groups (p=0.33). In BIMA, 13-week changes from baseline favored the HBO2 group (-3.6±6.4) versus sham (-0.3±5.2; p=0.02). No between-group differences were found when COBRIT composite scoring was applied to BIMA. Overall, HBO2 effects were maximized when the post hoc global measure derived from both studies was applied to the data.

CONCLUSIONS

Composite total scores in HOPPS and BIMA were consistent with primary study results. The global measures considered may offer utility as endpoints to achieve maximal HBO2 effect in future trials of the mTBI population.

IDS

clinicaltrials.gov Identifiers NCT01611194 (BIMA) and NCT01306968 (HOPPS).

Analysis of magnetic resonance spectroscopy relative metabolite ratios in mild traumatic brain injury and normative controls

INTRODUCTION

We evaluated magnetic resonance spectroscopy (MRS) in United States military personnel with persistent symptoms after mild traumatic brain injury (mTBI), comparing over time two groups randomized to receive hyperbaric oxygen or sham chamber sessions and a third group of normative controls.

METHODS

Active-duty or veteran military personnel and normative controls underwent MRS outcome measures at baseline, 13 weeks (mTBI group only), and six months. Participants received 3.0 Tesla brain MRS for analysis of water-suppressed two-dimensional (2D) multivoxel 1H-MRS of the brain using point resolved spectroscopy (PRESS) with volume selection localized above the lateral ventricles and within the brain parenchyma, of which one voxel was chosen in each hemisphere without artifact. Script-based automatic data processing was used to assess N-acetylaspartate (NAA), creatine (Cr), and choline (Cho). Metabolite ratios for white matter were then calculated for NAA/Cr (Area), Cho/Cr (Area), and Cho/NAA (Area). These ratios were compared using standard analysis methodology.

RESULTS

There were no observable differences between participants with mTBI and normative controls nor any observable changes over time in the NAA/Cr (area), Cho/Cr (area), and Cho/NAA (area) ratios. Similarly, the control and injured participants were indistinguishable.

DISCUSSION

While participants with mild TBI showed no difference in MRS compared to normative controls, our results are limited by the few voxels chosen and potentially by less sensitive MRS markers.

Extended follow-up in a randomized trial of hyperbaric oxygen for persistent post-concussive symptoms

To date, several Department of Defense (DoD) and civilian studies have evaluated hyperbaric oxygen for mild forms of traumatic brain injury. Prior to the DoD-sponsored "Brain Injury and Mechanisms of Action of Hyperbaric Oxygen for Persistent Post-Concussive Symptoms after Mild Traumatic Brain Injury (mTBI) (BIMA)" trial, none included post-intervention follow-up beyond three to six months. Post-hoc attempts at long-term follow-up were complicated by low participation and potential self-selection bias. BIMA planned for follow-up through 12 months but was amended to add post-concussive and post-traumatic stress disorder, quality of life, pain, depression, anxiety, and alcohol use assessments at 24 and 36 months. A total of 42 of 71 BIMA participants consented to extendedfollow-up, and 40 and 14 completed a 24- or 36-month visit, respectively, representing an overall response rate of 59% and 20%. Participants who completed extended follow-up were similar to the study group that did not in terms of demographics, perceived intervention allocation, and initial response to intervention. There were no significant differences at 24 or 36 months between intervention groups, and group mean scores were near pre-intervention values. This return to baseline could be due to waning treatment effect, selection bias, or participant or perception effects. Though BIMA implemented several participant retention strategies, more frequent participant contact and increased compensation might improve long-term retention in future studies. clinicaltrials.gov Identifier NCT01611194.

Hyperbaric oxygen for mTBI-associated PCS and PTSD: Pooled analysis of results from Department of Defense and other published studies

BACKGROUND

Some clinical trials report improvement in persistent post-concussive symptoms (PCS) with hyperbaric oxygen (HBO2) following mild traumatic brain injury (mTBI), but questions remain regarding the utility of HBO2 for PCS, the effects of HBO2 on post-traumatic stress disorder (PTSD), and the influences of sham control exposures.

METHODS

A systematic review and pooled analysis was conducted to summarize available evidence for HBO2 in mTBI-associated PCS ± PTSD. Data aggregated from four Department of Defense (DoD) studies with participant-level data (n=254) were grouped into pooled HBO2 and sham intervention groups. Changes from baseline to post-intervention on PCS, PTSD, and neuropsychological measures were assessed using linear mixed models to evaluate main intervention and intervention-by-baseline PTSD effects. Potential dose-response relationships to oxygen partial pressures were investigated. Intervention effects from three other published studies with summary-level participant data (n=135) were also summarized..

RESULTS

Pooled DoD data analyses indicated trends toward improvement favoring HBO2 for PCS (Rivermead Total Score: -2.3, 95% CI [-5.6, 1.0], p=0.18); PTSD (PTSD Checklist Total Score: -2.7, 95% CI [-5.8, 0.4], p=0.09); and significant improvement in verbal memory (CVLT-II Trial 1-5 Free Recall: 3.8; 95% CI [1.0, 6.7], p=0.01). A dose-response trend to increasing oxygen partial pressure was also found, with a greater HBO2 effect in mTBI-associated PTSD suggested. The direction of results was consistent with other published studies.

CONCLUSION

A definitive clinical trial, with an appropriate control group, should be considered to identify the optimal HBO2 dosing regimen for individuals with mTBI-associated PTSD ± PCS.

Central auditory processing disorders after mild traumatic brain injury

Auditory processing disorders are common following mild traumatic brain injury (mTBI), but the neurocircuitry involved is not well understood. The present study used functional MRI to examine auditory cortex activation patterns during a passive listening task in a normative population and mTBI patients with and without clinical central auditory processing deficits (APD) as defined by the SCAN-3:A clinical battery. Patients with mTBI had overall patterns of lower auditory cortex activation during the listening tasks as compared to normative controls. A significant lateralization pattern (pairwise t-test; p⟨0.05) was observed in normative controls and in those with mTBI and APD during single-side stimulation. Additionally, baseline connectivity between left and right auditory cortices was lower in mTBI patients than in controls (p=0.01) and significantly reduced in the mTBI with APD group (p=0.008). Correlation was also observed between bilateral task-related activation and competing words subscore of the SCAN-3:A. These findings suggest the passive listening task is well suited to probe auditory function in military personnel with an mTBI diagnosis. Further, the study supports the use of multiple approaches for detecting and assessing central auditory deficits to improve monitoring of short- and long-term outcomes.

Adverse events and blinding in two randomized trials of hyperbaric oxygen for persistent post-concussive symptoms

Safety monitoring and successful blinding are important features of randomized, blinded clinical trials. We report chamber- and protocol-related adverse events (AEs) for participants enrolled in two randomized, double-blind clinical trials of hyperbaric oxygen (HBO2) for persistent post-concussive symptoms clinicaltrials.gov identifiers NCT01306968, HOPPS, and NCT01611194, BIMA), as well as the success of maintaining the blind with a low-pressure sham control arm. In both studies, participants were randomized to receive HBO2 (1.5 atmospheres absolute, >99% oxygen) or sham chamber sessions (1.2 atmospheres absolute, room air). In 143 participants undergoing 4,245 chamber sessions, chamber-related adverse events were rare (1.1% in the HOPPS study, 2.2% in the BIMA study). Minor, non-limiting barotrauma was the most frequently reported. Rarely, some participants experienced headache with chamber sessions. No serious adverse events were associated with chamber sessions. An allocation questionnaire completed after intervention revealed that the sham control arm adequately protected the blind in both trials. Participants based allocation assumptions on symptom improvement or lack of symptom improvement and could not discern intervention arm by pressure, smell, taste, or gas flow.

Age-Accelerated Reduction in Cortical Surface Area in United States Service Members and Veterans with Mild Traumatic Brain Injury and Post-Traumatic Stress Disorder

Despite the prevalence of combat-related mild traumatic brain injury (mTBI) and relatively high incidence of concurrent post-traumatic stress disorder (PTSD), the joint effect of these conditions on the brain is not well understood. Further, few studies in the mTBI or PTSD populations focus on cortical surface area measures, despite known disruptions to cytoarchitecture of the cortex. This study examines the effects of comorbid mTBI and PTSD on age-related surface area changes across the cortex, as compared with a group with mTBI only. While a direct comparison of PTSD versus non-PTSD groups showed little difference on surface area measures, several regions showed a decline in surface area, with increasing age and a significant PTSD-by-age interaction effect, indicating an age-dependent decrease in surface area in those with both mTBI and PTSD. The findings suggest an apparent age-accelerated shrinking of the cortical surface area in some regions when mTBI and PTSD are present, a pattern that was not consistently found in those with mTBI only. Among the several cortical regions with significant age-by-group interactions were bilateral posterior cingulate cortex (left: p = 0.03; right: p = 0.02), isthmus of the cingulate (left: p = 0.016; right: p = 0.001), and lateral orbitofrontal cortex (left: p = 0.038; right: p = 0.02). It is possible that these findings are related to a larger pattern of premature neurodegeneration and age-acceleration noted in those with long-term PTSD.

Effects of mild traumatic brain injury and post-traumatic stress disorder on resting-state default mode network connectivity

Mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) are common outcomes for service members. Abnormal connectivity within neural networks has been reported in the resting brain of mTBI and PTSD patients, respectively; however, the potential role of PTSD in changes to neural networks following injury has not been studied in detail. Using a data-driven approach, the present analysis aimed to elucidate resting state functional connectivity in the default mode network (DMN) in those with mTBI only and those with comorbid mTBI and PTSD. A secondary analysis focused on distinct contributions by the anterior and posterior DMN components. Group-level independent component analysis was used to identify the DMN, and a dual-regression method was utilized to measure connectivity within the overall network and its anterior (medial prefrontal cortex) and posterior (posterior cingulate cortex) nodes. Connectivity within the overall DMN was significantly higher for the mTBI only group (p = 0.001), as compared to controls and mTBI + PTSD. For all subjects with mTBI, network connectivity correlated inversely with PTSD checklist score (p < 0.05). Additionally, distinct associations (p < 0.05) between medial prefrontal cortex connectivity and PTSD symptoms and, separately, posterior cingulate cortex connectivity and mTBI-related cognitive deficits were found. To our knowledge, this is the first study to report a differential relationship between DMN components and both post-traumatic symptoms and cognitive outcomes.

Accelerated age-related cortical thinning in mild traumatic brain injury

INTRODUCTION

Mild traumatic brain injury (mTBI) can result in many structural abnormalities in the cerebral cortex. While thinning of the cortex has been shown in mTBI patients, there is high regional variability in reported findings. High-resolution imaging can elucidate otherwise unnoticed changes in cortical measures following injury. This study examined age-related patterns of cortical thickness in U.S. active duty service members and veterans with a history of mTBI (n = 66) as compared to a normative population (n = 67).

METHODS

Using a fully automated cortical parcellation methodology, cortical thickness measures were extracted from 31 bilateral cortical regions for all participants.

RESULTS

The effect of diagnosis and age on cortical thickness (group × age interaction) was found to be significant (p < 0.05) for many regions, including bilateral parietal and left frontal and temporal cortices. Findings held for a male-only subset, and there was no effect of time since injury in any regions.

CONCLUSIONS

The presence of mTBI appeared to accelerate age-related cortical thinning across the cortex in our study population.

Comprehensive Evaluation of Healthy Volunteers Using Multi-Modality Brain Injury Assessments: An Exploratory, Observational Study

Introduction: Even though mild traumatic brain injury is common and can result in persistent symptoms, traditional measurement tools can be insensitive in detecting functional deficits after injury. Some newer assessments do not have well-established norms, and little is known about how these measures perform over time or how cross-domain assessments correlate with one another. We conducted an exploratory study to measure the distribution, stability, and correlation of results from assessments used in mild traumatic brain injury in healthy, community-dwelling adults. Materials and Methods: In this prospective cohort study, healthy adult men and women without a history of brain injury underwent a comprehensive brain injury evaluation that included self-report questionnaires and neurological, electroencephalography, sleep, audiology/vestibular, autonomic, visual, neuroimaging, and laboratory testing. Most testing was performed at 3 intervals over 6 months. Results: The study enrolled 83 participants, and 75 were included in the primary analysis. Mean age was 38 years, 58 were male, and 53 were civilians. Participants did not endorse symptoms of post-concussive syndrome, PTSD, or depression. Abnormal neurological examination findings were rare, and 6 had generalized slowing on electroencephalography. Actigraphy and sleep diary showed good sleep maintenance efficiency, but 21 reported poor sleep quality. Heart rate variability was most stable over time in the sleep segment. Dynavision performance was normal, but 41 participants had abnormal ocular torsion. On eye tracking, circular, horizontal ramp, and reading tasks were more likely to be abnormal than other tasks. Most participants had normal hearing, videonystagmography, and rotational chair testing, but computerized dynamic posturography was abnormal in up to 21% of participants. Twenty-two participants had greater than expected white matter changes for age by MRI. Most abnormal findings were dispersed across the population, though a few participants had clusters of abnormalities. Conclusions: Despite our efforts to enroll normal, healthy volunteers, abnormalities on some measures were surprisingly common. Trial Registration: This study was registered at www.clinicaltrials.gov, trial identifier NCT01925963.

Impact of Ketorolac on Opioid Consumption after Knee Arthroscopy

PURPOSE

The objective of this study was to examine postoperative opioid consumption in outpatients undergoing knee arthroscopy after a single dose of intravenous ketorolac.

METHODS

Patients ages 18-65 years old, weighing over 50kg and scheduled for knee arthroscopy were randomized to one of the four groups of preoperative ketorolac (0mg, 7.5mg, 15mg, 30mg). The primary outcome measured was postoperative opioid consumption. Secondary outcomes included visual analog scale pain scores, patient satisfaction scores, side effects and total postoperative anesthesia care unit time. Equivalency between ketorolac groups in opioid reduction relative to placebo was evaluated for each dose pair (7.5 vs. 15mg, 7.5 vs. 30mg, and 15 vs. 30mg). Linear regression models were used to examine associations between ketorolac dose with postoperative length of stay and patient satisfaction. A linear mixed model was used to evalaute the association between ketorolac dose and pain scores over time.

RESULTS

A total of 112 patients with comparable patient and procedural characteristics were enrolled. Equivalency in opioid reduction relative to placebo was not demonstrated between any examined ketorlac doses (7.5 vs. 15mg, P = 0.167; 7.5 vs. 30mg, P = 0.451; 15 vs. 30mg, P = 0.515). Compared to placebo, all ketorlac doses decreased postoperative pain scores (global P=0.012). Patient satisfaction and postoperative duration did not vary with ketorolac dose.

CONCLUSIONS

Although all ketorolac doses decreased PACU pain scores, equivalency in PACU opioid reduction between ketorolac doses was not demonstrated.

Hyperbaric oxygen for post-concussive symptoms in United States military service members: a randomized clinical trial

BACKGROUND

In prior military randomized trials, participants with persistent symptoms after mild traumatic brain injury (TBI) reported improvement regardless of receiving hyperbaric oxygen (HBO₂) or sham intervention. This study's objectives were to identify outcomes for future efficacy trials and describe changes by intervention.

METHODS

This Phase II, randomized, double-blind, sham-controlled trial enrolled military personnel with mild TBI and persistent post-concussive symptoms. Participants were randomized to receive 40 HBO₂ (1.5 atmospheres absolute (ATA), ⟩99% oxygen, 60 minutes) or sham chamber sessions (1.2 ATA, room air, 60 minutes) over 12 weeks. Participants and evaluators were blinded to allocation. Outcomes assessed at baseline, 13 weeks and six months included symptoms, quality of life, neuropsychological, neurological, electroencephalography, sleep, auditory, vestibular, autonomic, visual, neuroimaging, and laboratory testing. Participants completed 12-month questionnaires. Intention-to-treat results are reported.

RESULTS

From 9/11/2012 to 5/19/2014, 71 randomized participants received HBO₂ (n=36) or sham (n=35). At baseline, 35 participants (49%) met post-traumatic stress disorder (PTSD) criteria. By the Neurobehavioral Symptom Inventory, the HBO₂ group had improved 13-week scores (mean change -3.6 points, P=0.03) compared to sham (+3.9 points). In participants with PTSD, change with HBO₂ was more pronounced (-8.6 vs. +4.8 points with sham, P=0.02). PTSD symptoms also improved in the HBO₂ group, and more so in the subgroup with PTSD. Improvements regressed at six and 12 months. Hyperbaric oxygen improved some cognitive processing speed and sleep measures. Participants with PTSD receiving HBO₂ had improved functional balance and reduced vestibular complaints at 13 weeks.

CONCLUSIONS

By 13 weeks, HBO₂ improved post-concussive and PTSD symptoms, cognitive processing speed, sleep quality, and balance function, most dramatically in those with PTSD. Changes did not persist beyond six months. Several outcomes appeared sensitive to change; additional studies are warranted.

Simple and Procedural Reaction Time for Mild Traumatic Brain Injury in a Hyperbaric Oxygen Clinical Trial

Simple reaction time (SRT) and procedural reaction time (PRT) are speed-of-processing tasks in the Automated Neuropsychological Assessment Metrics (ANAM) that may be sensitive to mild traumatic brain injury (mTBI). The investigators measured SRT and PRT throughput (correct responses per minute) at baseline, 6 weeks, and 13 weeks in military personnel with mTBI randomized to local care or 40 chamber sessions (sham-1.2 atmospheres absolute [ATA] air, hyperbaric oxygen-1.5 ATA O2). Scores were assessed at baseline using univariate analysis of variance and across time with repeated measures methods. Data reported as throughput standard scores (mean = 100, SD = 15). Seventy-two participants with ongoing symptoms after mTBI enrolled in the study (three female, median age 31 years, mean three lifetime concussion events, most recent mTBI 23 months prior). Sixty-four had Automated Neuropsychological Assessment Metrics data at 13 weeks. SRT and PRT throughput standard scores were comparable across groups at baseline. Over time, SRT scores did not change in the hyperbaric oxygen or sham groups and decreased in the local care group. PRT throughput standard scores increased from baseline to mid-intervention and decreased from mid-intervention to postintervention in all groups. Repeated measures change over time in SRT (p = 0.23), and PRT (p = 0.17) scores were not different among groups. This study may be underpowered to detect statistically significant change.

Sleep assessments for a mild traumatic brain injury trial in a military population

Baseline sleep characteristics were explored for 71 U.S. military service members with mild traumatic brain injury (mTBI) enrolled in a post-concussive syndrome clinical trial. The Pittsburgh Sleep Quality Index (PSQI), sleep diary, several disorder-specific questionnaires, actigraphy and polysomnographic nap were collected. Almost all (97%) reported ongoing sleep problems. The mean global PSQI score was 13.5 (SD=3.8) and 87% met insomnia criteria. Sleep maintenance efficiency was 79.1% for PSQI, 82.7% for sleep diary and 90.5% for actigraphy; total sleep time was 288, 302 and 400 minutes, respectively. There was no correlation between actigraphy and subjective questionnaires. Overall, 70% met hypersomnia conditions, 70% were at high risk for obstructive sleep apnea (OSA), 32% were symptomatic for restless legs syndrome, and 6% reported cataplexy. Nearly half (44%) reported coexisting insomnia, hypersomnia and high OSA risk. Participants with post-traumatic stress disorder (PTSD) had higher PSQI scores and increased OSA risk. Older participants and those with higher aggression, anxiety or depression also had increased OSA risk. The results confirm poor sleep quality in mTBI with insomnia, hypersomnia, and OSA risk higher than previously reported, and imply sleep disorders in mTBI may be underdiagnosed or exacerbated by comorbid PTSD.

Neuropsychological assessments in a hyperbaric trial of post-concussive symptoms

Results of studies addressing the effect of mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) on symptoms and neuropsychological assessments are mixed regarding cognitive deficits in these populations. Neuropsychological assessments were compared between U.S. military service members with mTBI only (n=36) vs. those with mTBI÷ PTSD (n=35) from a randomized interventional study of mTBI participants with persistent post-concussive symptoms (PCS). The mTBI group endorsed worse symptoms than published norms on PCS, PTSD and pain scales (⟩50% abnormal on Neurobehavioral Symptom Inventory (NSI), PTSD Checklist-Civilian, McGill Pain Questionnaire-Short Form) and some quality of life domains. Worse symptom reporting was found in the mTBI÷ PTSD group compared to mTBI (e.g., mean NSI total score in mTBI 27.5 (SD=12.7), mTBI÷ PTSD 39.9 (SD=13.6), p⟨0.001). The mTBI÷PTSD group performed worse than mTBI on the Weschler Adult Intelligence Scale digit span (mean difference -1.5, 95% CI[-2.9,-0.1], p=0.04) and symbol search (mean difference -1.5, 95% CI[-2.7,-0.2], p=0.03) and Grooved Pegboard (dominant hand mean difference -7.0, 95% CI[-11.5,-2.4], p=0.003; non-dominant mean difference -9.8, 95% CI[-14.9,-4.7], p⟨0.001). Differences were detected in ANAM simple reaction time (p=0.04) and mathematical processing (p=0.03) but not verbal fluency or visuospatial memory assessments. Results indicate increased symptom severity and some cognitive deficits in mTBI÷ PTSD compared to mTBI alone.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01611194; https://clinicaltrials.gov/show/NCT01611194.

Review of recent non-hyperbaric oxygen interventions for mild traumatic brain injury

Traumatic brain injury (TBI) affects 3.2 to 5.3 million persons in the United States (U.S.), and the impact in the U.S. military is proportionally higher. Consensus is lacking regarding an accepted outcome to measure the effectiveness of interventions to improve the symptoms associated with TBI, and no standard-of-care treatment exists for mild TBI (mTBI). A recent literature review evaluated hyperbaric oxygen therapy (HBO₂) interventions, and findings were mixed. We conducted a systematic review of non-HBO₂ mTBI interventional trials published in 2005-2015 in military and civilian populations. A total of 154 abstracts, seven randomized controlled trials (RCTs) and five pilot studies were reviewed. RCTs were evaluated using Consolidated Standards of Reporting Trials criteria. Results indicated that studies published within the period of review were small pilot studies for rehabilitation therapy and motion capture or virtual reality gaming interventions. Neuropsychological assessments were commonly specified outcomes, and most studies included a combination of symptom and neuropsychological assessments. Findings indicated a lack of large-scale, well-controlled trials to address the symptoms and sequelae of this condition, but results of small exploratory studies show evidence of potentially promising interventions.

Hyperbaric oxygen for persistent post-concussive symptoms: long-term follow-up

We report results of an observational cohort study investigating long-term follow-up in participants from two completed United States military trials of hyperbaric oxygen (HBO₂) for persistent post-concussive symptoms (PCS), as well as challenges in recruitment and retention in active-duty military personnel. After informed consent, participants completed an electronic survey assessing PCS, post-traumatic stress disorder (PTSD), anxiety, depression and quality of life. Of 132 HBO₂ study participants, 40 (30%) completed the survey (42 could not be contacted; 50 were lost to follow-up or declined). All were male, age 28.1 ±6.6 years (mean ±1SD). Time to follow-up was 39.2 ±6.1 months. At follow-up, participants reported continued symptoms of PTSD, depression, anxiety and reduced quality of life. Among DARPA/VCU study participants, total PCS scores worsened in the 1.5 atmospheres absolute (ATA) equivalent HBO₂ group (mean change 7.4 ±15.8) and improved in the sham (-8.0 ±7.7) and 2.0 atmospheres absolute equivalent HBO₂ groups (-3.3 ±7.4). Individual changes varied widely, range -23 to +28 points. In participants from the HOPPS study, total PCS scores worsened in all groups: local care (10.5 ±8.7), sham (7.9 ±11.9) and 1.5 ATA HBO₂ (1.0 ±19.4). In this limited, cross-sectional sample, PCS and PTSD symptoms did not appear to improve over time by descriptive analyses. Low participation rates and potential response bias limit our ability to perform statistical hypothesis testing and to draw conclusions from these data. Future studies should prospectively plan longitudinal follow-up and regular engagement with participants to minimize attrition.

Linear analysis of heart rate variability in post-concussive syndrome

Heart rate variability (HRV) represents measurable output of coordinated structural and functional systems within the body and brain. Both mild traumatic brain injury (mTBI) and HRV are modulated by changes in autonomic nervous system function. We present baseline HRV results from an ongoing mTBI clinical trial. HRV was assessed via 24-hour ambulatory electrocardiography; recordings were segmented by physiological state (sleep, wakefulness, exercise, standing still). Time, frequency, and spatial domain measures were summarized and compared with symptoms, sleep quality, and neurological examination. Median low frequency/high frequency (LF/HF) ratio exceeded 1.0 across segments, indicating prevalence of sympathetic modulation. Abnormal Sharpened Romberg Test was associated with 29% LF/HF decrease (95% CI [2.1, 47.7], p=0.04); pathological nystagmus associated with decreased standard deviation of electrocardiogram R-R interval (SDNN) index (25% decrease, 95% CI [0.8, 43.4], p=0.04). Increased sympathetic modulation was associated with increased anger scores (19% LF/HF increase with 5-point State Trait Anger Expression Inventory-2 trait anger increase (95% CI [1.2, 39.1], p=0.04)). A 13% HF increase (95% CI [2.1, 25.7], p=0.02) was observed with increased Pittsburgh Sleep Quality Index scores. These results support autonomic nervous system dysfunction in service members after mTBI.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01611194; https://clinicaltrials.gov/show/NCT01611194.

Executive summary: The Brain Injury and Mechanism of Action of Hyperbaric Oxygen for Persistent Post-Concussive Symptoms after Mild Traumatic Brain Injury (mTBI) (BIMA) Study

The Brain Injury and Mechanism of Action of Hyperbaric Oxygen for Persistent Post-Concussive Symptoms after Mild Traumatic Brain Injury (mTBI) (BIMA) study, sponsored by the Department of Defense and held under an investigational new drug application by the Office of the Army Surgeon General, is one of the largest and most complex clinical trials of hyperbaric oxygen (HBO₂) for post-concussive symptoms (PCS) in U.S. military service members.

Hyperbaric oxygen for mild traumatic brain injury: Design and baseline summary

The Brain Injury and Mechanisms of Action of Hyperbaric Oxygen for Persistent Post-Concussive Symptoms after Mild Traumatic Brain Injury (mTBI) (BIMA) study, sponsored by the Department of Defense, is a randomized double-blind, sham-controlled clinical trial that has a longer duration of follow-up and more comprehensive assessment battery compared to recent HBO₂ studies. BIMA randomized 71 participants from September 2012 to May 2014. Primary results are expected in 2017. Randomized military personnel received hyperbaric oxygen (HBO₂) at 1.5 atmospheres absolute (ATA) or sham chamber sessions at 1.2 ATA, air, for 60 minutes daily for 40 sessions. Outcomes include neuropsychological, neuroimaging, neurological, vestibular, autonomic function, electroencephalography, and visual systems evaluated at baseline, immediately following intervention at 13 weeks and six months with self-report symptom and quality of life questionnaires at 12 months, 24 months and 36 months. Characteristics include: median age 33 years (range 21-53); 99% male; 82% Caucasian; 49% diagnosed post-traumatic stress disorder; 28% with most recent injury three months to one year prior to enrollment; 32% blast injuries; and 73% multiple injuries. This manuscript describes the study design, outcome assessment battery, and baseline characteristics. Independent of a therapeutic role of HBO₂, results of BIMA will aid understanding of mTBI.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01611194; https://clinicaltrials.gov/show/NCT01611194.

Effect of Intraoperative Phenylephrine Infusion on Redistribution Hypothermia During Cesarean Delivery Under Spinal Anesthesia

An observational clinical study to evaluate the effect of phenylephrine infusion on maternal temperatures during scheduled cesarean delivery under spinal anaesthesia was conducted in 40 ASA physical status II parturients. Following placement of spinal anesthesia, phenylephrine infusion was initiated at 40 μg/min and titrated to maintain mean arterial pressure within 20 percent of baseline. Maternal oral temperature, heart rate, and blood pressure were measured at baseline, spinal placement, every 10 minutes thereafter for 60 minutes. Phenylephrine dose received was documented every ten minutes. The range in maternal temperature change was 0.06-0.29°C. The lowest recorded temperature was 36.3°C. Decreased maternal temperature was associated with duration of anesthesia and cumulative phenylephrine dose in a univariate model (P<0.001 for all). The multivariable model showed an association between a greater decrease in maternal temperature with larger doses of phenylephrine being administered.

A simple but precise method for quantitative measurement of the quality of the laser focus in a scanning optical microscope

We report a method for characterizing the focussing laser beam exiting the objective in a laser scanning microscope. This method provides the size of the optical focus, the divergence of the beam, the ellipticity and the astigmatism. We use a microscopic‐scale knife edge in the form of a simple transmission electron microscopy grid attached to a glass microscope slide, and a light‐collecting optical fibre and photodiode underneath the specimen. By scanning the laser spot from a reflective to a transmitting part of the grid, a beam profile in the form of an error function can be obtained and by repeating this with the knife edge at different axial positions relative to the beam waist, the divergence and astigmatism of the postobjective laser beam can be obtained. The measured divergence can be used to quantify how much of the full numerical aperture of the lens is used in practice. We present data of the beam radius, beam divergence, ellipticity and astigmatism obtained with low (0.15, 0.7) and high (1.3) numerical aperture lenses and lasers commonly used in confocal and multiphoton laser scanning microscopy. Our knife‐edge method has several advantages over alternative knife‐edge methods used in microscopy including that the knife edge is easy to prepare, that the beam can be characterized also directly under a cover slip, as necessary to reduce spherical aberrations for objectives designed to be used with a cover slip, and it is suitable for use with commercial laser scanning microscopes where access to the laser beam can be limited.

Clinical Follow-Up of Paclitaxel-Eluting (TAXUS?) Stents for the Treatment of Saphenous Vein Graft Disease

BACKGROUND

Randomized trials in selected patient populations have demonstrated dramatic reductions in the incidence of in-stent restenosis (ISR) following implantation of paclitaxel-eluting (PE) coronary stents compared with bare metal stents in native coronary disease. The clinical outcome following implantation of PE stents for saphenous vein graft (SVG) stenosis is largely unknown.

AIM

To assess the safety and efficacy of PE coronary stents for the treatment of SVG stenosis in an unselected population.

METHODS

All patients who received PE stents for the treatment of SVG disease from May 1, 2003, to May 1, 2005, were entered into a prospectively collected database. Fifty-five patients were identified with 69 lesions. In-hospital and late major adverse cardiac events (MACE) including death, myocardial infarction (MI), and target lesion revascularization (TLR) were recorded as well as the rate of target vessel revascularization (TVR).

RESULTS

Mean follow-up was 13 months with 54 of the 55 patients contacted. The number of stents implanted was 1.12 +/- 0.37 per lesion and 1.38 +/- 0.59 per patient. Clinically significant procedural MACE was 0%. The late MACE rate was 9% with a 2% clinically driven TLR, a 4% coronary artery bypass graft (CABG), and a 4% TVR rate. There were four deaths, two cardiac and two noncardiac.

CONCLUSION

PE stents appear safe and effective in the treatment of SVG disease at a mean follow-up time of 13 months. Randomized studies are needed to further delineate the optimal management of this high-risk group.

Long-term clinical follow-up of sirolimus-eluting (CYPHER) coronary stents in the treatment of instent restenosis in an unselected population

Randomised trials in a highly selected patient population have demonstrated a dramatic reduction in the incidence of in-stent restenosis (ISR) following implantation of sirolimus-eluting (S-E) Cypher coronary stents compared with bare metal stents (BMS). The clinical outcome following implantation of S-E stents for treatment of complex, unselected BMS ISR is less well defined. The aim of this study was to assess the safety and efficacy of S-E coronary stents in the treatment of an unselected population of BMS ISR. All patients who received S-E stents for treatment of BMS ISR from May 1 2002-November 30 2003 at a single institution were entered into a prospectively collected database. In-hospital and long-term outcomes were collected. Sixty patients were identified who received S-E stents for the treatment of ISR. Four patients (6%) had undergone previous brachytherapy and 22% were diabetic. The most common target vessel was the left anterior descending coronary artery (40%), and 6% of lesions were in saphenous vein grafts (SVGs). The mean reference diameter was 2.67+/-0.52 (range 1.75-4.0) mm and the mean lesion length was 16.22+/-11.46 (range 3-68) mm. There were no procedural or in-hospital major adverse cardiac events (MACE). Long-term follow-up was available in 59 patients (98%). The 12-month MACE rate (cardiac death, myocardial infarction or target lesion revascularisation) was 12% with a 7% percutaneous coronary intervention rate and a 7% coronary artery bypass graft rate. There were no cardiac deaths and two non-cardiac deaths. Of the seven patients who had clinical restenosis at 12 months, four had previously failed brachytherapy and three involved SVGs. In conclusion, the use of S-E stents appears safe and efficacious in the treatment of an unselected population of BMS ISR with results comparing favourably with historical controls. Further randomised studies are needed to delineate the optimal management of this high risk group of patients.

Long-Term Follow-up of Renal Artery Stenting in an Australian Population

BACKGROUND

Renal artery stenosis comprises both atherosclerotic renovascular disease and fibromuscular dysplasia, and may be associated with refractory hypertension, acute 'flash' pulmonary oedema and renal failure. The long-term clinical effects of renal artery stenting remain unclear.

AIM

To assess the procedural and long-term safety and efficacy of renal artery stenting and its effect on blood pressure, antihypertensive medication usage and serum creatinine.

METHODS

All patients referred for renal artery stenting at our institution between September 1997 and December 2003 were entered into a prospectively collected database. Systolic and diastolic blood pressure, number of antihypertensive medications, serum creatinine and estimated glomerular filtration rate (eGFR) were recorded. Patients were followed-up at least six months post-procedure.

RESULTS

Eighty-nine patients underwent renal arteriography, with 110 stents deployed in 102 lesions. The procedural success rate was 99% with no procedural mortality. There were two cases of peri-procedural haemorrhage and one of sepsis. One patient developed renal and peripheral atheroemboli.

FOLLOW-UP

Mean follow-up was 28 months (range 6 months-7 years). Eight patients were lost to follow-up. There were nine deaths with a mean time to death of 20.7 months (range 12 months-3 years). There was a highly statistically significant fall in systolic blood pressure (BP) from 161.7+/-29.5 mmHg pre-procedure to 138.7+/-17.9 mmHg at long-term follow-up post-procedure (p<0.0001). The clinical restenosis rate was 6.2%. Renal function and eGFR remained stable and there was a borderline significant decrease in the number of antihypertensive medications used (p=0.05).

CONCLUSION

Renal artery stenting is safe and appears effective for the treatment of clinically significant renal artery stenosis.

Comparative outcomes of percutaneous coronary interventions in diabetics vs non-diabetics with prior coronary artery bypass grafting

AIMS

To determine the influence of diabetes on outcome after percutaneous coronary intervention in patients with prior coronary artery bypass grafting.

METHODS AND RESULTS

Patients with prior coronary artery bypass grafting undergoing percutaneous coronary intervention from 1 January 1996, to 31 August 2000, were divided into two groups based on whether or not they had diabetes, excluding patients with acute infarction or shock. Cox proportional hazards models were utilized to estimate the association between diabetes and adverse events. One thousand one hundred and fifty-three post-coronary artery bypass grafting percutaneous coronary intervention patients were identified (326 diabetics and 827 non-diabetics). Diabetics were younger, more likely to have hypertension, heart failure, and lower ejection fraction. Procedural characteristics and angiographic and procedural success rates were similar. Diabetes was associated with increased mortality (hazard ratio 1.58, 95% confidence intervals 1.10-2.27). Diabetes did not have a significant effect on mortality in patients treated for single-territory coronary disease (hazard ratio 1.44, 95% confidence intervals 0.69-3.02), but did in patients with multi-territory disease (hazard ratio 1.79, 95% confidence intervals 1.16-2.76). However, in diabetics with multi-territory disease who were completely revascularized with percutaneous coronary intervention, mortality was comparable to non-diabetics (hazard ratio 1.32, 95% confidence intervals 0.57-3.03).

CONCLUSION

Among percutaneous coronary intervention patients with prior coronary artery bypass grafting, diabetes portends an adverse prognosis.

Mammalian DNA beta-polymerase in base excision repair of alkylation damage

DNA beta-polymerase (beta-pol) carries out two critical enzymatic reactions in mammalian single-nucleotide base excision repair (BER): DNA synthesis to fill the repair patch and lyase removal of the 5'-deoxyribose phosphate (dRP) group following cleavage of the abasic site by apurinic/apyrimidinic (AP) endonuclease (1). The requirement for beta-pol in single-nucleotide BER is exemplified in mouse fibroblasts with a null mutation in the beta-pol gene. These cells are hypersensitive to monofunctional DNA methylating agents such as methyl methane-sulfonate (MMS) (2). This hypersensitivity is associated with an abundance of chromosomal damage and induction of apoptosis and necrotic cell death (3). We have found that beta-pol null cells are defective in repair of MMS-induced DNA lesions, consistent with a cellular BER deficiency as a causative agent in the observed hypersensitivity. Further, the N-terminal 8-kDa domain of beta-pol, which contains the dRP lyase activity in the wild-type enzyme, is sufficient to reverse the methylating agent hypersensitivity in beta-pol null cells. These results indicate that lyase removal of the dRP group is a pivotal step in BER in vivo. Finally, we examined MMS-induced genomic DNA mutagenesis in two isogenic mouse cell lines designed for study of the role of BER. MMS exposure strongly increases mutant frequency in beta-pol null cells, but not in wild-type cells. With MMS treatment, beta-pol null cells have a higher frequency of all six base-pair substitutions, suggesting that BER plays a role in protecting the cell against methylation-induced mutations.

Relationship between base excision repair capacity and DNA alkylating agent sensitivity in mouse monocytes

Base excision repair (BER) capacity and the level of DNA polymerase beta (beta-pol) are higher in mouse monocyte cell extracts when cells are treated with oxidative stress-inducing agents. Consistent with this, such treated cells are more resistant to the cytotoxic effects of methyl methanesulfonate (MMS), which produces DNA damage considered to be repaired by the BER pathway. In contrast to the up-regulation of BER in oxidatively stressed cells, cells treated with the cytokine interferon-gamma (IFN-gamma) are down-regulated in both BER capacity of the cell extract and level of beta-pol. We find that cells treated with IFN-gamma are more sensitive to MMS than untreated cells. These results demonstrate concordance between beta-pol level, BER capacity and cellular sensitivity to a DNA methylation-inducing agent. The results suggest that BER is a significant defense mechanism in mouse monocytes against the cytotoxic effects of methylated DNA.

Influence of coronary thrombus on outcome of percutaneous coronary angioplasty in the current era (the Mayo Clinic experience)

Earlier studies documented an increased risk of percutaneous coronary intervention (PCI) in patients with angiographic evidence of thrombus. With newer antiplatelet agents and stents, it is not known whether thrombus is a risk factor after PCI. This study examines whether outcome of PCI in patients with thrombus has improved, and whether thrombus is associated with adverse outcome after PCI in the current era. This single-institution retrospective analysis of PCI in 7,184 patients was divided into 2 periods: group I, 1990 to 1995 (n = 3,640), and group II, 1996 to 1999 (n = 3,544). The groups were subdivided according to the presence or absence of angiographic thrombus before PCI. We compared the outcome of PCI for patients with and without thrombus in group II. A comparison was made in the 2 groups in patients with angiographic thrombus. Procedural success improved in group II compared with group I patients with thrombus (93% vs 88%, p <0.001). There was significant reduction in abrupt closure in the recent era in patients with thrombus (4% vs 7%, p = 0.01). In group II, procedural success remained lower in patients with (93% vs 96%) than without thrombus (p <0.001). After adjusting for the significant univariate characteristics of group II patients, thrombus remained an independent predictor of Q-wave infarction (odds ratio 3.78; 95% confidence interval [CI], 1.8 to 8.0; p <0.0013) and the composite end point of death, Q-wave infarction, and emergency bypass surgery (odds ratio 2.37; 95% CI 1.4 to 4.1; p = 0.002). There was a trend toward increased in-hospital death among patients with thrombus (odds ratio 2.06; 95% CI 0.9 to 4.8; p = 0.09). The 1-year outcome after successful PCI was similar for those with and without thrombus. Despite improvement in the outcome of patients with thrombus undergoing PCI in recent years, thrombus is still an independent predictor of adverse in-hospital outcomes after PCI.

Optimisation of the management of patients with coronary heart disease and type 2 diabetes mellitus

Type 2 diabetes mellitus is a prevalent disease in Westernised society, and more than 50% of individuals with diabetes mellitus die from cardiovascular causes. The underlying metabolic defect of type 2 diabetes mellitus is a combination of insulin resistance and decreased secretion of insulin by pancreatic beta-cells. Insulin resistance commonly precedes the onset of type 2 diabetes mellitus and is usually associated with a metabolic syndrome including hypertension, dyslipidaemia and obesity. Treatment of known cardiovascular risk factors, including hyperglycaemia, dyslipidaemia, hypertension and smoking, plays a key role in delaying the onset and progression of coronary heart disease (CHD) and other forms of atherosclerosis in patients with diabetes mellitus. Sulphonylureas should be used with caution in patients with CHD but aspirin (acetylsalicylic acid), beta-blockers and ACE inhibitors play an important role in the medical management of patients with established coronary artery disease and diabetes mellitus. Patients with diabetes mellitus represent a higher risk group of patients after both percutaneous and surgical coronary revascularisation and the decision regarding the choice of revascularisation procedure should take into account angiographic characteristics, clinical status and patient preference. Patients presenting with diabetes mellitus and acute myocardial infarction should be considered for reperfusion therapy with either urgent thrombolytic therapy or primary percutaneous coronary intervention.

The effect of endothelin-1 on nuclear factor kappa B in macrophages

Nuclear factor kappaB (NF-kappaB) is a transcriptional factor which may be pivotal in the pathogenesis of atherosclerosis. Endothelin-1 (ET-1) is a peptide with proatherogenic properties. We hypothesized that ET-1 may act through activation of NF-kappaB and degradation of IkappaB-alpha, the cytosolic inhibitor of NF-kappaB activation, to create an atherogenic environment. The human monocytic cell line THP-1 was stimulated with ET-1 +/- the ET antagonist, BQ788 and the proteosome inhibitor, PSI. LPS was used as a positive control. Gel shift assays for NF-kappaB activity and Western blot analysis for IkappaB-alpha were performed. Both LPS and ET-1 led to activation of NF-kappaB in nuclear extracts [3.4 +/- 0.45 (LPS) and 2.9 +/- 0.26 (ET-1) fold increase in Arbitrary Densitometric Units (ADU) compared with negative control (P < 0.005 in both cases)]. In the presence of the ETB antagonist, BQ788, NF-kappaB activation was attenuated and not different from control (1.7 +/- 0.24 fold DU compared with negative control; P = NS). In addition, both LPS and ET-1 mediated NF-kappaB activation were attenuated by preincubation with the proteosome inhibitor, PSI (1.3 +/- 0.58 and 1.1 +/- 0.3 fold increase in ADU compared with negative control respectively). Both LPS and ET-1 led to a decrease in the amount of IkappaB-alpha present in the THP-1 cytoplasmic extracts (2.1 +/- 1.5% and 54 +/- 15.7% of ADU vs negative control (P < 0.05). NF-kappaB is activated by ET-1 in human THP-1 monocytes. This data supports a role for the ETs in the development of inflammation in the vessel wall in atherosclerosis.

DNA lesion bypass polymerases open up

Structures of catalytic fragments of two DNA lesion bypass DNA polymerases, yeast DNA polymerase eta and an archeon DinB homolog, have recently been solved. These structures share several common architectural and structural features observed in other DNA polymerases, including a hand-like architecture with fingers, palm, and thumb subdomains. The new structures provide the first structural insights into DNA lesion bypass. The fingers and thumb are smaller than those in other DNA polymerases. Modeled substrates suggest that the fingers in the vicinity of the incoming nucleotide is closed, a conformation not previously observed for an unliganded polymerase. However, the template binding pocket appears to be more open, indicating that for DNA polymerase eta, a covalently linked thymine-thymine dimer could be accommodated.

DNA polymerase beta -mediated long patch base excision repair. Poly(ADP-ribose)polymerase-1 stimulates strand displacement DNA synthesis

Recently, photoaffinity labeling experiments with mouse cell extracts suggested that PARP-1 functions as a surveillance protein for a stalled BER intermediate. To further understand the role of PARP-1 in BER, we examined the DNA synthesis and flap excision steps in long patch BER using a reconstituted system containing a 34-base pair BER substrate and five purified human enzymes: uracil-DNA glycosylase, apurinic/apyrimidinic endonuclease, DNA polymerase beta, flap endonuclease-1 (FEN-1), and PARP-1. PARP-1 stimulates strand displacement DNA synthesis by DNA polymerase beta in this system; this stimulation is dependent on the presence of FEN-1. PARP-1 and FEN-1, therefore, cooperate to activate long patch BER. The results are discussed in the context of a model for BER sub-pathway choice, illustrating a dual role for PARP-1 as a surveillance protein for a stalled BER intermediate and an activating factor for long patch BER DNA synthesis.

Identification of MAL2, a novel member of the mal proteolipid family, though interactions with TPD52-like proteins in the yeast two-hybrid system

The TPD52 (tumor protein D52)-like proteins are small coiled-coil motif-bearing proteins which were first identified though their expression in human breast carcinoma. TPD52-like proteins are known to interact in hetero-and homomeric fashions, but there are no known heterologous binding partners for these proteins. We now report the cloning of a novel member of the MAL proteolipid family, named MAL2, though its interaction with a TPD52L2 bait in a yeast two-hybrid screen. MAL2 is predicted to be 176 residues (19 kDa) with four transmembrane domains and is 35.8% identical to MAL, a proteolipid required in apical vesicle transport. The MAL2 prey bound all TPD52-like baits tested in the yeast two-hybrid system and in vitro translation of MAL2 produced a single 19-kDa (35)S-labeled protein which specifically bound full-length GST-Tpd52 in GST pull-down assays. The gene MAL2, which was localized to human chromosomal band 8q23 and shown to consist of four exons, is predominantly expressed in human kidney, lung, and liver. Our study has therefore identified a novel member of the MAL proteolipid family and potentially implicates TPD52-like proteins in vesicle transport.

Comparison of self-expanding and balloon-expandable stents for the reduction of restenosis

To compare the efficacy of self-expanding (SE) and balloon-expandable (BE) stents in native coronary arteries, we randomly assigned 1,096 patients with new and restenotic lesions to receive either device. Baseline demographics and coronary angiographic characteristics were similar in the 2 groups. The incidence of major adverse cardiac events including death, myocardial infarction, bypass surgery, and repeat intervention was similar for both groups at 1 month (2.9% vs 3.1% for SE vs BE, respectively) and at 9 months (19.3% vs 20.1%, SE vs BE respectively). In a subgroup of patients who underwent follow-up angiography (n = 250), the binary restenosis rates (24.2% vs 18.7%, p = 0.30), late loss (0.98 vs 94 mm, p = 0.60), and loss index (0.55 vs 55, p = 0.95) were not significantly different for both groups. In 62 patients who underwent intravascular ultrasound examination (IVUS), there was a trend toward a lower incidence of edge tears in the SE group (6% vs 23%, p = 0.06). Follow-up IVUS analysis showed that the minimum stent area of the SE stent increased by 33% at 6 months, whereas no change occurred in the BE stents; this was accompanied by a greater degree of intimal proliferation in the SE stents compared with BE stents (3.1 +/- 2.0 vs 1.7 +/- 1.7 mm(2)). Thus, the SE stents had similar clinical and angiographic outcomes in patients with lesions in native coronary arteries.

Photoaffinity labeling of mouse fibroblast enzymes by a base excision repair intermediate. Evidence for the role of poly(ADP-ribose) polymerase-1 in DNA repair

To examine the interaction of mammalian base excision repair (BER) enzymes with DNA intermediates formed during BER, we used a novel photoaffinity labeling probe and mouse embryonic fibroblast cellular extracts. The probe was formed in situ, using an end-labeled oligonucleotide containing a synthetic abasic site; this site was incised by apurinic/apyrimidinic endonuclease creating a nick with 3'-hydroxyl and 5'-reduced sugar phosphate groups at the margins, and then a dNMP carrying a photoreactive adduct was added to the 3'-hydroxyl group. With near-UV light (312 nm) exposure of the extract/probe mixture, six proteins were strongly labeled. Four of these include poly(ADP-ribose) polymerase-1 (PARP-1) and the BER participants flap endonuclease-1, DNA polymerase beta, and apurinic/apyrimidinic endonuclease. The amount of the probe cross-linked to PARP-1 was greater than that cross-linked to the other proteins. The specificity of PARP-1 labeling was examined using various competitor oligonucleotides and DNA probes with alternate structures. PARP-1 labeling was stronger with a DNA representing a BER intermediate than with a nick in double-stranded DNA. These results indicate that proteins interacting preferentially with a photoreactive BER intermediate can be selected from the crude cellular extract.

Modulation of retinal endothelial cell behaviour by insulin-like growth factor I and somatostatin analogues: implications for diabetic retinopathy

Evidence suggests the involvement of growth hormone (GH), insulin-like growth factor I (IGF-I) and somatostatin in the pathology associated with diabetic retinopathy. We examined the effect of IGF-I on human retinal endothelial cell (HREC) survival following high glucose exposure and serum starvation, examined the signalling pathways mediating the protective effect of IGF-I on HREC, and characterized somatostatin receptor-induced retinal endothelial cell death. IGF-I (10 ng/ml) protected HREC from apoptosis induced by high glucose and serum starvation. Wortmannin, a specific inhibitor of phosphotidylinositol-3-kinase, blocks the ability of IGF-I to protect HREC from apoptosis. Incubation of HREC in serum-free medium caused a time-dependent increase in c-Jun N-terminal kinase (JNK) activity, and continuous culture of HREC in the presence of IGF-I or vascular endothelial growth factor (VEGF) prevented JNK activation and arrested apoptosis. Activation of tyrosine kinase receptors results in extracellular signal-related kinase (ERK) activation and activation of ERK is required for proliferation. Both IGF-I and VEGF produced a time- and concentration-dependent increase in the activation of ERK. Type 2 and type 3 somatostatin receptors have been implicated in cell-cycle arrest and apoptosis. Activation of the type 3 receptor in HREC resulted in cell death. These studies suggest that IGF-I is critical for HREC survival, and that somatostatin analogues acting through the type 3 receptor have direct effects on retinal endothelial cells. Furthermore, it appears that the therapeutic efficacy of somatostatin analogues lies not only in systemic inhibition of GH, but also in modulating local growth factor effects.

A type IB topoisomerase with DNA repair activities

Previously we have characterized type IB DNA topoisomerase V (topo V) in the hyperthermophile Methanopyrus kandleri. The enzyme has a powerful topoisomerase activity and is abundant in M. kandleri. Here we report two characterizations of topo V. First, we found that its N-terminal domain has sequence homology with both eukaryotic type IB topoisomerases and the integrase family of tyrosine recombinases. The C-terminal part of the sequence includes 12 repeats, each repeat consisting of two similar but distinct helix-hairpin-helix motifs; the same arrangement is seen in recombination protein RuvA and mammalian DNA polymerase beta. Second, on the basis of sequence homology between topo V and polymerase beta, we predict and demonstrate that topo V possesses apurinic/apyrimidinic (AP) site-processing activities that are important in base excision DNA repair: (i) it incises the phosphodiester backbone at the AP site, and (ii) at the AP endonuclease cleaved AP site, it removes the 5' 2-deoxyribose 5-phosphate moiety so that a single-nucleotide gap with a 3'-hydroxyl and 5'-phosphate can be filled by a DNA polymerase. Topo V is thus the prototype for a new subfamily of type IB topoisomerases and is the first example of a topoisomerase with associated DNA repair activities.

The therapeutic problem of proliferative diabetic retinopathy: targeting somatostatin receptors

Clinical management of proliferative diabetic retinopathy has changed very little in the last 5 decades, relying primarily on laser ablation of the retinal vasculature. Several lines of clinical and experimental evidence suggest that somatostatin analogues may be efficacious in inhibiting neovascularization associated with proliferative retinopathy but the mechanism of action for these compounds is unclear. Inhibition of growth hormone secretion and the subsequent suppression of insulin-like growth factor 1 (IGF-1) production by somatostatin has been suggested as the mechanism of action, however, in vitro studies suggest that somatostatin analogues suppress endothelial cell growth through a direct, somatostatin receptor-mediated inhibition of pro-survival signaling pathways. The advent of a new generation of modified peptide and peptidomimetic somatostatin analogues has allowed investigators to more carefully define the receptor subtypes responsible for somatostatin-induced endothelial cell death and may eventually lead to the clinical development of somatostatin analogues that can reduce endothelial cell proliferation, independent of suppression of circulating hormone levels.

Infarct artery reocclusion after primary angioplasty, stent placement, and thrombolytic therapy for acute myocardial infarction

BACKGROUND

The benefits of thrombolytic therapy for acute myocardial infarction (AMI) are limited by reocclusion of the infarct-related artery, which occurs in 25% to 30% of patients after successful reperfusion. The frequency of reocclusion after balloon angioplasty and stenting in this setting is less well documented. The aim of this study was to analyze the frequency and timing of reocclusion after percutaneous transluminal coronary angioplasty (PTCA) and stent placement during AMI from all available studies compared with previously published reocclusion rates after thrombolysis.

METHODS AND RESULTS

The previously published thrombolysis data included 4231 patients in 19 studies with > or = 75 patients. Only PTCA studies with > or = 50 patients and stent studies with > or = 30 patients, in which routine angiographic follow-up was obtained in > or = 60% of patients, were included. Ten PTCA studies with a total of 1943 patients were analyzed, with follow-up angiography in 1391 (72%). Reocclusion rates ranged from 5% to 16.7%. The stent studies included 698 patients from 7 studies, with follow-up angiography in 92%. Reocclusion rates ranged from 0% to 6%. With the use of logistic regression analysis with allowance for overdispersion, there was a significantly lower rate of reocclusion after PTCA (odds ratio, 0.38; confidence interval, 0.24 to 0.57; P <.0001) and stent placement (odds ratio, 0.11; confidence interval, 0.05 to 0.22; P <.0001) compared with thrombolysis. Reocclusion after stent placement was lower than after PTCA (odds ratio, 0.28; confidence interval, 0.13 to 0.6; P <.0001).

CONCLUSIONS

Reocclusion after PTCA and stent placement during AMI is less frequent than after thrombolysis. This may contribute to the superior outcome of patients treated with PTCA and stent placement in this setting.

5'-Deoxyribose phosphate lyase activity of human DNA polymerase iota in vitro

DNA polymerase iota (pol iota) is one of several recently discovered DNA polymerases in mammalian cells whose function is unknown. We report here that human pol iota has an intrinsic 5'-deoxyribose phosphate (dRP) lyase activity. In reactions reconstituted with uracil-DNA glycosylase (UDG), apurinic/apyrimidinic (AP) endonuclease and DNA ligase I, pol iota can use its dRP lyase and polymerase activities to repair G*U and A*U pairs in DNA. These data and three distinct catalytic properties of pol iota implicate it in specialized forms of base excision repair (BER).