The effect of disease misclassification on the ability to detect a gene-environment interaction: implications of the specificity of case definitions for research on Gulf War illness

BACKGROUND

Since 1997, research on Gulf War illness (GWI) has predominantly used 3 case definitions-the original Research definition, the CDC definition, and modifications of the Kansas definition-but they have not been compared against an objective standard.

METHODS

All 3 case definitions were measured in the U.S. Military Health Survey by a computer-assisted telephone interview in a random sample (n = 6,497) of the 1991 deployed U.S. military force. The interview asked whether participants had heard nerve agent alarms during the conflict. A random subsample (n = 1,698) provided DNA for genotyping the PON1 Q192R polymorphism.

RESULTS

The CDC and the Modified Kansas definition without exclusions were satisfied by 41.7% and 39.0% of the deployed force, respectively, and were highly overlapping. The Research definition, a subset of the others, was satisfied by 13.6%. The majority of veterans meeting CDC and Modified Kansas endorsed fewer and milder symptoms; whereas, those meeting Research endorsed more symptoms of greater severity. The group meeting Research was more highly enriched with the PON1 192R risk allele than those meeting CDC and Modified Kansas, and Research had twice the power to detect the previously described gene-environment interaction between hearing alarms and RR homozygosity (adjusted relative excess risk due to interaction [aRERI] = 7.69; 95% CI 2.71-19.13) than CDC (aRERI = 2.92; 95% CI 0.96-6.38) or Modified Kansas without exclusions (aRERI = 3.84; 95% CI 1.30-8.52) or with exclusions (aRERI = 3.42; 95% CI 1.20-7.56). The lower power of CDC and Modified Kansas relative to Research was due to greater false-positive disease misclassification from lower diagnostic specificity.

CONCLUSIONS

The original Research case definition had greater statistical power to detect a genetic predisposition to GWI. Its greater specificity favors its use in hypothesis-driven research; whereas, the greater sensitivity of the others favor their use in clinical screening for application of future diagnostic biomarkers and clinical care.

Evaluation of a Gene-Environment Interaction of PON1 and Low-Level Nerve Agent Exposure with Gulf War Illness: A Prevalence Case-Control Study Drawn from the U.S. Military Health Survey's National Population Sample

BACKGROUND

Consensus on the etiology of 1991 Gulf War illness (GWI) has been limited by lack of objective individual-level environmental exposure information and assumed recall bias.

OBJECTIVES

We investigated a prestated hypothesis of the association of GWI with a gene-environment (GxE) interaction of the paraoxonase-1 (PON1) Q192R polymorphism and low-level nerve agent exposure.

METHODS

A prevalence sample of 508 GWI cases and 508 nonpaired controls was drawn from the 8,020 participants in the U.S. Military Health Survey, a representative sample survey of military veterans who served during the Gulf War. The PON1 Q192R genotype was measured by real-time polymerase chain reaction (RT-PCR), and the serum Q and R isoenzyme activity levels were measured with PON1-specific substrates. Low-level nerve agent exposure was estimated by survey questions on having heard nerve agent alarms during deployment.

RESULTS

The GxE interaction of the Q192R genotype and hearing alarms was strongly associated with GWI on both the multiplicative [prevalence odds ratio (POR) of the interaction=3.41; 95% confidence interval (CI): 1.20, 9.72] and additive (synergy index=4.71; 95% CI: 1.82, 12.19) scales, adjusted for measured confounders. The Q192R genotype and the alarms variable were independent (adjusted POR in the controls=1.18; 95% CI: 0.81, 1.73; p=0.35), and the associations of GWI with the number of R alleles and quartiles of Q isoenzyme were monotonic. The adjusted relative excess risk due to interaction (aRERI) was 7.69 (95% CI: 2.71, 19.13). Substituting Q isoenzyme activity for the genotype in the analyses corroborated the findings. Sensitivity analyses suggested that recall bias had forced the estimate of the GxE interaction toward the null and that unmeasured confounding is unlikely to account for the findings. We found a GxE interaction involving the Q-correlated PON1 diazoxonase activity and a weak possible GxE involving the Khamisiyah plume model, but none involving the PON1 R isoenzyme activity, arylesterase activity, paraoxonase activity, butyrylcholinesterase genotypes or enzyme activity, or pyridostigmine.

DISCUSSION

Given gene-environment independence and monotonicity, the unconfounded aRERI>0 supports a mechanistic interaction. Together with the direct evidence of exposure to fallout from bombing of chemical weapon storage facilities and the extensive toxicologic evidence of biochemical protection from organophosphates by the Q isoenzyme, the findings provide strong evidence for an etiologic role of low-level nerve agent in GWI. https://doi.org/10.1289/EHP9009.

Pathophysiology and Molecular Imaging of Diabetic Foot Infections

Diabetic foot infection is the leading cause of non-traumatic lower limb amputations worldwide. In addition, diabetes mellitus and sequela of the disease are increasing in prevalence. In 2017, 9.4% of Americans were diagnosed with diabetes mellitus (DM). The growing pervasiveness and financial implications of diabetic foot infection (DFI) indicate an acute need for improved clinical assessment and treatment. Complex pathophysiology and suboptimal specificity of current non-invasive imaging modalities have made diagnosis and treatment response challenging. Current anatomical and molecular clinical imaging strategies have mainly targeted the host's immune responses rather than the unique metabolism of the invading microorganism. Advances in imaging have the potential to reduce the impact of these problems and improve the assessment of DFI, particularly in distinguishing infection of soft tissue alone from osteomyelitis (OM). This review presents a summary of the known pathophysiology of DFI, the molecular basis of current and emerging diagnostic imaging techniques, and the mechanistic links of these imaging techniques to the pathophysiology of diabetic foot infections.

Pathophysiology and Molecular Imaging of Diabetic Foot Infections

Diabetic foot infection is the leading cause of non-traumatic lower limb amputations worldwide. In addition, diabetes mellitus and sequela of the disease are increasing in prevalence. In 2017, 9.4% of Americans were diagnosed with diabetes mellitus (DM). The growing pervasiveness and financial implications of diabetic foot infection (DFI) indicate an acute need for improved clinical assessment and treatment. Complex pathophysiology and suboptimal specificity of current non-invasive imaging modalities have made diagnosis and treatment response challenging. Current anatomical and molecular clinical imaging strategies have mainly targeted the host's immune responses rather than the unique metabolism of the invading microorganism. Advances in imaging have the potential to reduce the impact of these problems and improve the assessment of DFI, particularly in distinguishing infection of soft tissue alone from osteomyelitis (OM). This review presents a summary of the known pathophysiology of DFI, the molecular basis of current and emerging diagnostic imaging techniques, and the mechanistic links of these imaging techniques to the pathophysiology of diabetic foot infections.

Epidemiology and risk factors for varicella zoster virus reactivation in heart transplant recipients

Heart transplant (HT) recipients are at higher risk of varicella zoster virus (VZV) reactivation. Risk factors for VZV reactivation are currently not well defined, impeding the ability to design and implement strategies to minimize the burden of this illness in this population. Automated data extraction tools were used to retrieve data from the electronic health record (EHR) of all adult HT recipients at our center between 2010 and 2016. Information from the Organ Procurement and Transplantation Network Standard Analysis and Research Files was merged with the extracted data. Potential cases were manually reviewed and adjudicated using consensus definitions. Cumulative incidence and risk factors for VZV reactivation in HT recipients were assessed by the Kaplan-Meier method and Cox modeling, respectively. In 203 HT recipients, the cumulative incidence of VZV reactivation at 8-years post-transplantation was 26.4% (95% CI: 17.8-38.0). The median time to VZV reactivation was 2.1 years (IQR, 1.5-4.1). Half (14/28) of the cases experienced post-herpetic neuralgia (PHN). Post-transplant CMV infection (HR 9.05 [95% CI: 3.76-21.77) and post-transplant pulse-dose steroids (HR 3.19 [95% CI: 1.05-9.68]) were independently associated with a higher risk of VZV reactivation in multivariable modeling. Identification of risk factors will aid in the development of targeted preventive strategies.

The use of automated data extraction tools to develop a solid organ transplant registry: Proof of concept study of bloodstream infections

BACKGROUND

We created an electronic health record-based registry using automated data extraction tools to study the epidemiology of bloodstream infections (BSI) in solid organ transplant recipients. The overarching goal was to determine the usefulness of an electronic health record-based registry using data extraction tools for clinical research in solid organ transplantation.

METHODS

We performed a retrospective single-center cohort study of adult solid organ transplant recipients from 2010 to 2015. Extraction tools were used to retrieve data from the electronic health record, which was integrated with national data sources. Electronic health records of subjects with positive blood cultures were manually adjudicated using consensus definitions. One-year cumulative incidence, risk factors for BSI acquisition, and 1-year mortality were analyzed by Kaplan-Meier method and Cox modeling, and 30-day mortality with logistic regression.

RESULTS

In 917 solid organ transplant recipients the cumulative incidence of BSI was 8.4% (95% confidence interval 6.8-10.4) with central line-associated BSI as the most common source. The proportion of multidrug-resistant isolates increased from 0% in 2010 to 47% in 2015 (p = 0.03). BSI was the strongest risk factor for 1-year mortality (HR=8.44; 4.99-14.27; p<0.001). In 11 of 14 deaths, BSI was the main cause or contributory in patients with non-rapidly fatal underlying conditions.

CONCLUSIONS

Our study illustrates the usefulness of an electronic health record-based registry using automated extraction tools for clinical research in the field of solid organ transplantation. A BSI reduces the 1-year survival of solid organ transplant recipients. The most common sources of BSIs in our studies are preventable.

2664. Impact of Multidrug-Resistant Bacterial Infections in Solid-Organ Transplantation: The Value of Electronic Health Records-Based Registries and Data Extraction Tools

Background

Antimicrobial usage is the most important driver of antimicrobial resistance. Despite compelling reasons to use antimicrobials judiciously, it has been challenging to implement antimicrobial stewardship programs (ASP) in the solid-organ transplant (SOT) population. The objective of our study is to assess the impact of multidrug-resistant bacterial infections (MDRBI) on the 1-year post-transplant survival in SOT recipients.

Methods

In this retrospective cohort study, we included all patients with a first SOT from January 1, 2010–December 31, 2016 at our institution. Patients were followed for a year. Data extraction tools retrieved information from the electronic health record (EHR) and merged it with data from the Social Security Death Index (SSDI) and Standard Transplant Analysis and Research (STAR) files. Charts of subjects with positive cultures were manually reviewed and adjudicated using CDC/ECDC and CDC/NHSN criteria. The 1-year MDRBI cumulative incidence and survival were estimated using the Kaplan–Meier method and compared using the Log-rank test. A Cox proportional hazards model was used to identify predictors of 1-year mortality. Cytomegalovirus (CMV) Infection, renal replacement therapy (RRT), and post-transplant extra-corporeal membrane oxygenation (ECMO) were analyzed as a time-dependent covariate.

Results

1,112 SOT recipients met inclusion criteria. Patient characteristics are shown in Table 1. 105 patients had at least one MDRBI. The cumulative incidence of MDRBI was 9.7% (95% CI 14.6–5.9) (Figure 1). The most common MDR pathogens were Vancomycin-resistant Enterococci and E. coli (Figure 2A), and the most common sites of infection were urinary tract infection and pneumonia (Figure 2B). The 1-year post-SOT survival in patients with MDR infection was 75.3% (95% CI 82.8–65.2) (Figure 2C). In multivariable analysis, MDRBI (HR = 6.2 [3.5–10.9]) and post-SOT RRT (HR = 17.8 [10.3–30.6]) were associated with an increased risk of 1-year mortality (Table 2).

Conclusion

MDRBI significantly impacts the 1-year survival of SOT recipients. Our results highlight the need to strengthen ASP measures in SOT. Additionally, this study illustrates the versatility of EHR-based registries and data extraction tools in the field of transplantation.

Disclosures

All authors: No reported disclosures.

Superiority of Out-of-Office Blood Pressure for Predicting Hypertensive Heart Disease in Non-Hispanic Black Adults

Black Americans suffer disproportionately from hypertension and hypertensive heart disease. Out-of-office blood pressure (BP) is more predictive for cardiovascular complications than clinic BP; however, the relative abilities of clinic and out-of-office BP to predict left ventricular hypertrophy in black and white adults have not been established. Thus, we aimed to compare associations of out-of-office and clinic BP measurement with left ventricular hypertrophy by cardiac magnetic resonance imaging among non-Hispanic black and white adults. In this cross-sectional study, 1262 black and 927 white participants of the Dallas Heart Study ages 30 to 64 years underwent assessment of standardized clinic and out-of-office (research staff-obtained) BP and left ventricular mass index. In multivariable-adjusted analyses of treated and untreated participants, out-of-office BP was a stronger determinant of left ventricular hypertrophy than clinic BP (odds ratio per 10 mm Hg, 1.48; 95% CI, 1.34-1.64 for out-of-office systolic BP and 1.15 [1.04-1.28] for clinic systolic BP; 1.71 [1.43-2.05] for out-of-office diastolic BP, and 1.03 [0.86-1.24] for clinic diastolic BP). Non-Hispanic black race/ethnicity, treatment status, and lower left ventricular ejection fraction were also independent determinants of hypertrophy. Among treated Blacks, the differential association between out-of-office and clinic BP with hypertrophy was more pronounced than in treated white or untreated participants. In conclusion, protocol-driven supervised out-of-office BP monitoring provides important information that cannot be gleaned from clinic BP assessment alone. Our results underscore the importance of hypertension management programs outside the medical office to prevent hypertensive heart disease, especially in high-risk black adults. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT00344903.

Estimating the Health and Economic Impacts of Changes in Local Air Quality

OBJECTIVES

To demonstrate the benefits-mapping software Environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE), which integrates local air quality data with previously published concentration-response and health-economic valuation functions to estimate the health effects of changes in air pollution levels and their economic consequences.

METHODS

We illustrate a local health impact assessment of ozone changes in the 10-county nonattainment area of the Dallas-Fort Worth region of Texas, estimating the short-term effects on mortality predicted by 2 scenarios for 3 years (2008, 2011, and 2013): an incremental rollback of the daily 8-hour maximum ozone levels of all area monitors by 10 parts per billion and a rollback-to-a-standard ambient level of 65 parts per billion at only monitors above that level.

RESULTS

Estimates of preventable premature deaths attributable to ozone air pollution obtained by the incremental rollback method varied little by year, whereas those obtained by the rollback-to-a-standard method varied by year and were sensitive to the choice of ordinality and the use of preloaded or imported data.

CONCLUSIONS

BenMAP-CE allows local and regional public health analysts to generate timely, evidence-based estimates of the health impacts and economic consequences of potential policy options in their communities.

Gulf War illness associated with abnormal auditory P1 event-related potential: Evidence of impaired cholinergic processing replicated in a national sample

Our team previously reported event-related potential (ERP) and hyperarousal patterns from a study of one construction battalion of the U.S. Naval Reserve who served during the 1991 Persian Gulf War. We sought to replicate these findings in a sample that was more representative of the entire Gulf War-era veteran population, including male and female participants from four branches of the military. We collected ERP data from 40 veterans meeting Haley criteria for Gulf War syndromes 1-3 and from 22 matched Gulf War veteran controls while they performed an auditory oddball task. Reports of hyperarousal from the ill veterans were significantly greater than those from the control veterans, and P1 amplitudes in Syndromes 2 and 3 were significantly higher than P1 amplitudes in Syndrome 1, replicating our previous findings. Many of the contributors to the generation of the P1 potential are also involved in the regulation of arousal and are modulated by cholinergic and dopaminergic systems-two systems whose dysfunction has been implicated in Gulf War illness. These differences among the three syndrome groups where their means were on either side of controls is a replication of our previous ERP study and is consistent with previous imaging studies of this population.

1133. Epidemiology of Invasive Fungal Infections in Lung Transplant Recipients: Harnessing Data Mining Tools to Build a Comprehensive Database

Background

Despite advances in diagnostic and therapeutic tools, mortality of invasive fungal disease (IFD) in lung transplant (LT) recipients remains high. This study aimed to describe the epidemiology of IFD in LT recipients at a large academic center.

Methods

This retrospective single-center cohort study included all first-time LT recipients transplanted between 2010 and 2016 at the University of Texas Southwestern Medical Center in Dallas, TX. Data mining tools were used to extract data from the electronic health record and merge it with information from the Scientific Registry of Transplant Recipients and the Social Security Death Index (Figure 1). Medical records of subjects with positive fungal serologies, cultures or histopathology were manually reviewed and presence of IFD adjudicated using standardized definitions. Multivariable analysis was conducted using Cox proportional hazard models, with input variables treated as time dependent covariates where applicable, to identify risk factors for IFD and 1-year mortality.

Results

Of 393 LT recipients that met inclusion criteria, 68 (17%) developed a proven or probable IFD with median time to onset of 110 days (IQR 46–213) (Figure 2). The most common pathogens were: Aspergillus sp. (41%), and Candida sp. (34%). The most common sites of IFD were: lower respiratory tract (38%), tracheobronchial (25%), pleural/pericardial (15%), and bloodstream (7%). In multivariable analysis, incidence of IFD was associated with male gender (P = 0.02; HR=2.05, 95% CI 1.14–3.68), and prior CMV disease (P = 0.003; HR=4.16, 95% CI 1.65–10.50) (Figure 3). The 12-week mortality after the first episode of IFD was 3%; IFD was not associated with 1-year mortality (P = 0.51, HR = 1.27, 95% CI 0.63–2.53).

Conclusion

IFD is a frequent complication after LT. Efforts to identify risk factors may help guide the development of targeted interventions to reduce the burden of IFD in this vulnerable population.

Disclosures

All authors: No reported disclosures.

1554. Reactivation of Varicella Zoster Virus in Solid Organ Transplant Recipients: Identification of Risk Factors Using Data Mining Tools

Background

We created a retrospective database of solid-organ transplant (SOT) recipients using innovative data mining tools. This study describing the epidemiology of Varicella Zoster Virus (VZV) reactivation in SOT serves as a proof of concept of such techniques in clinical research.

Methods

The study design was a retrospective single-center cohort study. Using data mining tools, information was extracted from the electronic medical record and merged with data from the Scientific Registry of Transplant Recipients. First SOT from January 1, 2010–December 31, 2016 were included. Charts of subjects with ICD9/10 codes related to VZV/Herpes infections; positive VZV PCR, DFA or cultures; and recipients of acyclovir, valacyclovir or famciclovir were manually reviewed. The cumulative incidence was calculated using the Kaplan–Meier method. Cox proportional hazards models were used to identify risk factors for VZV reactivation among heart transplant (HT) recipients.

Results

A total of 1,076 SOT recipients met inclusion criteria (203 heart, 395 lung, 280 kidney, 198 liver). Forty-nine patients experienced at least one episode of VZV reactivation; median time post-transplant was 2.25 years (IQR 1.44–4.20 years). The cumulative incidence was 11.9% at 8 years post-transplant. Heart transplant (HT) recipients were at highest risk (Figure 1), with an 8-year cumulative incidence of 26.3% (Figure 2). Thirty-nine of 49 (80%) patients presented with localized disease and 4/49 (8%) with disseminated disease. In multivariable analysis (Figure 3), the risk of VZV reactivation in HT recipients after 12 months (47 patients) was associated with CMV infection before 12 months (HR [95% CI] = 4.74 [1.67–13.47]). Postherpetic neuralgia (PHN) occurred in 23/49 (47%), recurrence in 3/49 (6%), and other complications in 11/49 (22%). In univariable analysis, no risk factors for PHN were identified.

Conclusion

HT recipients are at highest risk for VZV reactivation. CMV infection before 1 year is associated with increased risk of VZV reactivation after 1 year in HT. This information may help design clinical trials of the recombinant zoster vaccine.

Disclosures

All authors: No reported disclosures.

Identification of biologically active δ-lactone eicosanoids as paraoxonase substrates

The mammalian paraoxonases (PONs 1, 2 and 3) are a family of esterases that are highly conserved within and between species. They exhibit antioxidant and anti-inflammatory activities. However, their physiological function(s) and native substrates are uncertain. Previous structure-activity relationship studies demonstrate that PONs have a high specificity for lipophilic lactones, suggesting that such compounds may be representative of native substrates. This report describes the ability of PONs to hydrolyze two bioactive δ-lactones derived from arachidonic acid, 5,6-dihydroxy-eicosatrienoic acid lactone (5,6-DHTL) and cyclo-epoxycyclopentenone (cyclo-EC). Both lactones were very efficiently hydrolyzed by purified PON3. PON1 efficiently hydrolyzed 5,6-DHTL, but with a specific activity about 15-fold lower than PON3. 5,6-DHTL was a poor substrate for PON2. Cyclo-EC was a poor substrate for PON1 and not hydrolyzed by PON2. Studies with the PON inhibitor EDTA and a serine esterase inhibitor indicated that the PONs are the main contributors to hydrolysis of the lactones in human and mouse liver homogenates. Studies with homogenates from PON3 knockout mouse livers indicated that >80% of the 5,6-DHTL and cyclo-EC lactonase activities were attributed to PON3. The findings provide further insight into the structural requirements for PONs substrates and support the hypothesis that PONs, particularly PON1 and PON3, evolved to hydrolyze and regulate a class of lactone lipid mediators derived from polyunsaturated fatty acids.

Solid Organ Transplantation (SOT) and Data Mining: Bloodstream Infections (BSI) Have a Significant Impact on One-Year Survival, and qSOFA ≥ 2 Predicts 30-Day Mortality

Background

We created a retrospective and prospective database of SOT recipients using innovative data mining tools. This study describing the epidemiology of BSI in SOT serves as a proof of concept of such techniques in clinical research.

Methods

The design of the study was a retrospective, single-center, cohort study. Data mining tools were used to extract information from the electronic medical record and merged it with data from the SRTR (Figure 1). First SOT from January 1, 2010 to December 31, 2015 were included. Charts of subjects with positive blood cultures were manually reviewed and adjudicated using CDC/NHSN and SCCM/ESICM criteria. The 1-year cumulative incidence was calculated using the Kaplan–Meier method. Cox proportional hazards models were used to identify risk factors for BSI and 1-year mortality. BSI was analyzed as a time-dependent covariate in the mortality model. Fisher’s exact test and chi-square were used to identify risk factors for 30-day mortality and MDRO.

Results

A total of 917 SOT recipients met inclusion criteria. Seventy-five patients experienced at least one BSI. The cumulative incidence was 8.4% (95% CI 6.8–10.4) (Figure 2). The onset of the first BSI episode was: 30 episodes (40%) <1 month, 33 (44%) 1–6 months, and 12 (16%) >6 months. The most common pathogens were Klebsiella sp. (16%), Vancomycin-resistant E. faecium (12%), E. coli (12%), CoNS (12%), and Candida sp. (9.3%). Nineteen isolates (25%) were identified as MDRO; the risk of MDRO was highest <1 month compared with 1–6 and >6 months (44.8 vs. 12.1 vs. 16.7; P = 0.01). The most common source of BSI was CLABSI (29%) (Figure 3). In multivariable analysis, the risk of BSI was associated with organ type (HR [95% CI] = Multiorgan 3.5 [1.1–11.6], liver 2.5 [1.1–5.4], heart 2.4 [1.1–5.1]) and acquisition of a BSI was associated with a higher 1-year mortality (HR = 8.7 [5.1–14.7]). In univariable analysis, a polymicrobial BSI (14.7 vs. 57.1%; P = 0.02), qSOFA ≥ 2 (0.0 vs. 25.5%; P = 0.02) and septic shock (3.9 vs. 52.2%; P < 0.001) were associated with an increased risk of death at 30 days.

Conclusion

A BSI significantly affects the 1-year survival of SOT recipients. A qSOFA ≥ 2 can be used to identify patients at risk for death. Additionally, this study illustrates the potential of data mining tools to study infectious complications.

Disclosures

All authors: No reported disclosures.

Association of the serum myeloperoxidase/high-density lipoprotein particle ratio and incident cardiovascular events in a multi-ethnic population: Observations from the Dallas Heart Study

BACKGROUND AND AIMS

Myeloperoxidase (MPO), a product of systemic inflammation, promotes oxidation of lipoproteins; whereas, high-density lipoprotein (HDL) exerts anti-oxidative effects in part via paraoxonase-1 (PON1). MPO induces dysfunctional HDL particles; however, the interaction of circulating levels of these measures in cardiovascular disease (CVD) has not been studied in humans. We tested whether serum levels of MPO indexed to HDL particle concentration (MPO/HDLp) are associated with increased CVD risk in a large multiethnic population sample, free of CVD at baseline.

METHODS

Levels of MPO, HDL-C, and HDL particle concentration (HDLp) by NMR were measured at baseline in 2924 adults free of CVD. The associations of MPO/HDLp with incident ASCVD (first non-fatal myocardial infarction, non-fatal stroke, coronary revascularization, or CVD death) and total CVD were assessed in Cox proportional-hazards models adjusted for traditional risk factors. The median follow-up period was 9.4 years.

RESULTS

Adjusted for sex and race/ethnicity, MPO/HDLp was associated directly with body mass index, smoking status, high-sensitivity C-reactive protein, and interleukin 18, and inversely with age, HDL-C levels, HDL size, and PON1 arylesterase activity, but not with cholesterol efflux. In fully adjusted models, the highest versus lowest quartile of MPO/HDLp was associated with a 74% increase in incident ASCVD (aHR, 1.74, 95% CI 1.12-2.70) and a 91% increase in total incident CVD (aHR, 1.91, 95% CI 1.27-2.85).

CONCLUSIONS

Increased MPO indexed to HDL particle concentration (MPO/HDLp) at baseline is associated with increased risk of incident CVD events in a population initially free of CVD over the 9.4 year period.

Electrophysiological correlates of semantic memory retrieval in Gulf War Syndrome 2 patients

Gulf War veterans meeting criteria for Haley Syndrome 2 of Gulf War illness endorse a particular constellation of symptoms that include difficulty with processing information, word-finding, and confusion. To explore the neural basis of their word-finding difficulty, we assessed event-related potentials (ERPs) associated with semantic memory retrieval in 22 veterans classified as Syndrome 2 and 28 veterans who served as controls. We recorded EEGs while subjects judged whether pairs of words that represented object features combined to elicit a retrieval of an object memory or no retrieval. Syndrome 2 subjects' responses were significantly slower, and those participants were less accurate than controls on the retrieval trials, but they performed similarly on the nonretrieval trials. Analysis of the ERPs revealed a difference between retrievals and nonretrievals that has previously been detected around 750ms at the left temporal region was present in both the Syndrome 2 patients and controls. However, the Syndrome 2 patients also showed an ERP difference between retrievals and nonretrievals at the midline parietal region that had a scalp voltage polarity opposite from that recorded at the left temporal area. We hypothesize that the similarities between task performance and ERP patterns in Syndrome 2 veterans and in patients with amnestic mild cognitive impairment reflect disordered thalamic cholinergic neural activity, possibly in the dorsomedial nucleus.

Vestibular Dysfunction in Gulf War Syndrome

METHODS: Vestibular complaints of Gulf War veterans were characterized by a nested case-control study of 23 veterans with 3 different Gulf War syndromes and 20 matched control subjects. All subjects completed a standardized symptom questionnaire and underwent standard audiovestibular tests administered by audiologists blinded to group identities.

RESULTS: The prevalence of reported dizzy spells was higher in veterans with Gulf War syndromes 1 (100%), 2 (85%), and 3 (100%) than in controls (25%, P < 0.0001). Dizzy spells were more frequent, lasted longer, and involved a wider variety of accompanying symptoms in veterans with syndrome 2 than in those with syndromes 1 and 3. Audiovestibular testing showed greater interocular asymmetry of nystagmic velocity on sinusoidal harmonic acceleration in syndromes 1 ( P = 0.015) and 2 ( P = 0.002), greater asymmetry of saccadic velocity in syndrome 2 ( P = 0.4), diminished nystagmic velocity after caloric stimulation bilaterally in syndrome 3 (P = 0.02 to 0.04), more subjects with pathologic nystagmus ( P = 0.09), and greater interside asymmetry of wave I to III interpeak latency on auditory brain stem response in syndromes 1 ( P = 0.005) and 2 ( P = 0.07). Asymmetry of gain on sinusoidal harmonic acceleration and pathologic nystagmus were most strongly associated with symptoms of paroxysmal vertigo (P = 0.002 and 0.07, respectively); asymmetry of saccadic velocity, with the severity of vertigo (P = 0.004); and abnormal caloric response, with chronic dysequilibrium ( P = 0.006).

CONCLUSIONS: The findings are compatible with a subtle neurologic injury from organophosphate-induced delayed neurotoxicity.

Cognitive Slowing in Gulf War Illness Predicts Executive Network Hyperconnectivity: Study in a Population-Representative Sample

Cognitive slowing is a prevalent symptom observed in Gulf War Illness (GWI). The present study assessed the extent to which functional connectivity between dorsolateral prefrontal cortex (DLPFC) and other task-relevant brain regions was predictive of GWI-related cognitive slowing. GWI patients (n = 54) and healthy veteran controls (n = 29) were assessed on performance of a processing speed task (the Digit Symbol Substitution Task; DSST) while undergoing functional magnetic resonance imaging (fMRI). GWI patients were slower on the DSST relative to controls. Bilateral DLPFC connectivity with task-relevant nodes was altered in GWI patients compared to healthy controls during DSST performance. Moreover, hyperconnectivity in these networks predicted GWI-related increases in reaction time on the DSST, whereas hypoconnectivity did not. These results suggest that GWI-related cognitive slowing reflects reduced efficiency in cortical networks.

Abstract 97: Association of the Serum Myeloperoxidase/High-Density Lipoprotein Particle Ratio and Incident Cardiovascular Events in a Multi-Ethnic Population: Observations From the Dallas Heart Study

Introduction: Myeloperoxidase (MPO) promotes oxidation of lipoproteins whereas high-density lipoprotein (HDL) exerts anti-oxidative effects in part via paraoxonase-1 (PON1). MPO can induce dysfunctional HDL particles; however, the interaction of circulating levels of these measures in cardiovascular disease (CVD) has not been studied in humans. We hypothesized that increased serum levels of MPO indexed to HDL particle concentration would be associated with an adverse phenotype with increased CVD risk and tested this hypothesis in a large multiethnic population free of CVD at baseline.

Methods: Levels of MPO, HDL-C, and HDL particle concentration (HDLp) by NMR were measured at baseline in 2924 adults free of CVD (57% women, 49% black). The associations of the MPO/HDLp ratio with incident ASCVD (first nonfatal myocardial infarction, nonfatal stroke, coronary revascularization, or CVD death) and total CVD were assessed in Cox proportional-hazards models adjusted for traditional risk factors (age, sex, race, hypertension, smoking, total cholesterol, and statin use). The median follow-up period was 9.4 years.

Results: MPO/HDLp was associated directly with total cholesterol, C-reactive protein, interleukin 18, and body mass index, and inversely with PON1 arylesterase activity, HDL-C, and HDL size. In adjusted models, the highest versus lowest quartile of MPO/HDLp was associated with a 74% increase in incident ASCVD (aHR, 1.74, 95% CI 1.12-2.70) and a 91% increase in total CVD (aHR, 1.91, 95% CI 1.27-2.85).

Conclusion: Increasing MPO indexed to HDL particle concentration at baseline is associated with increased risk of incident CVD events in a population initially free of CVD, reflecting increased inflammation and decreased PON1 arylesterase activity. This is the first report of the MPO/HDLp ratio in a large human cohort. Further studies are warranted investigating MPO/HDLp as a biomarker of HDL metabolism and CVD risk.

Memory and functional brain differences in a national sample of U.S. veterans with Gulf War Illness

Roughly 26-32% of U. S. veterans who served in the 1991 Persian Gulf War report suffering from chronic health problems. Memory complaints are regularly reported by ill Gulf War veterans (GWV), but limited data verify their complaints. This study investigated episodic memory and brain function in a nationally representative sample of GWV, using a face-name memory task and functional magnetic resonance imaging during encoding. A syndrome classification system was used to subdivide ill GWV into the three major Gulf War Illness syndrome types, "impaired cognition" (GWV-1), "confusion ataxia" (GWV-2), and "central pain" (GWV-3). Memory and brain function of ill GWV were contrasted to deployed and nondeployed well GWV controls (GWV-C). Ill GWV exhibited impaired memory function relative to GWV-C but the patterns of functional brain differences varied. Brain activation differentiated the GWV-C from the ill GWV. The different syndrome types also differed from one another in several brain regions. Additionally, the current study was the first to observe differences in brain function between deployed and nondeployed GWV-C. These results provide (1) evidence of memory impairment in ill GWV and differentiate the syndrome types at a functional neurobiological level, and (2) the role of deployment in the war on brain function.

Self-Administered Outpatient Antimicrobial Infusion by Uninsured Patients Discharged from a Safety-Net Hospital: A Propensity-Score-Balanced Retrospective Cohort Study

BACKGROUND

Outpatient parenteral antimicrobial therapy (OPAT) is accepted as safe and effective for medically stable patients to complete intravenous (IV) antibiotics in an outpatient setting. Since, however, uninsured patients in the United States generally cannot afford OPAT, safety-net hospitals are often burdened with long hospitalizations purely to infuse antibiotics, occupying beds that could be used for patients requiring more intensive services. OPAT is generally delivered in one of four settings: infusion centers, nursing homes, at home with skilled nursing assistance, or at home with self-administered therapy. The first three-termed healthcare-administered OPAT (H-OPAT)--are most commonly used in the United States by patients with insurance funding. The fourth--self-administered OPAT (S-OPAT)--is relatively uncommon, with the few published studies having been conducted in the United Kingdom. With multidisciplinary planning, we established an S-OPAT clinic in 2009 to shift care of selected uninsured patients safely to self-administration of their IV antibiotics at home. We undertook this study to determine whether the low-income mostly non-English-speaking patients in our S-OPAT program could administer their own IV antimicrobials at home with outcomes as good as, or better than, those receiving H-OPAT.

METHODS AND FINDINGS

Parkland Hospital is a safety-net hospital serving Dallas County, Texas. From 1 January 2009 to 14 October 2013, all uninsured patients meeting criteria were enrolled in S-OPAT, while insured patients were discharged to H-OPAT settings. The S-OPAT patients were trained through multilingual instruction to self-administer IV antimicrobials by gravity, tested for competency before discharge, and thereafter followed at designated intervals in the S-OPAT outpatient clinic for IV access care, laboratory monitoring, and physician follow-up. The primary outcome was 30-d all-cause readmission, and the secondary outcome was 1-y all-cause mortality. The study was adequately powered for readmission but not for mortality. Clinical, sociodemographic, and outcome data were collected from the Parkland Hospital electronic medical records and the US census, constituting a historical prospective cohort study. We used multivariable logistic regression to develop a propensity score predicting S-OPAT versus H-OPAT group membership from covariates. We then estimated the effect of S-OPAT versus H-OPAT on the two outcomes using multivariable proportional hazards regression, controlling for selection bias and confounding with the propensity score and covariates. Of the 1,168 patients discharged to receive OPAT, 944 (81%) were managed in the S-OPAT program and 224 (19%) by H-OPAT services. In multivariable proportional hazards regression models controlling for confounding and selection bias, the 30-d readmission rate was 47% lower in the S-OPAT group (adjusted hazard ratio [aHR], 0.53; 95% CI 0.35-0.81; p = 0.003), and the 1-y mortality rate did not differ significantly between the groups (aHR, 0.86; 95% CI 0.37-2.00; p = 0.73). The S-OPAT program shifted a median 26 d of inpatient infusion per patient to the outpatient setting, avoiding 27,666 inpatient days. The main limitation of this observational study-the potential bias from the difference in healthcare funding status of the groups-was addressed by propensity score modeling.

CONCLUSIONS

S-OPAT was associated with similar or better clinical outcomes than H-OPAT. S-OPAT may be an acceptable model of treatment for uninsured, medically stable patients to complete extended courses of IV antimicrobials at home.

Word-finding impairment in veterans of the 1991 Persian Gulf War

Approximately one quarter of 1991 Persian Gulf War Veterans experience cognitive and physiological sequelae that continue to be unexplained by known medical or psychological conditions. Difficulty coming up with words and names, familiar before the war, is a hallmark of the illness. Three Gulf War Syndrome subtypes have been identified and linked to specific war-time chemical exposures. The most functionally impaired veterans belong to the Gulf War Syndrome 2 (Syndrome 2) group, for which subcortical damage due to toxic nerve gas exposure is the suspected cause. Subcortical damage is often associated with specific complex language impairments, and Syndrome 2 veterans have demonstrated poorer vocabulary relative to controls. 11 Syndrome 1, 16 Syndrome 2, 9 Syndrome 3, and 14 age-matched veteran controls from the Seabees Naval Construction Battalion were compared across three measures of complex language. Additionally, functional magnetic resonance imaging (fMRI) was collected during a covert category generation task, and whole-brain functional activity was compared between groups. Results demonstrated that Syndrome 2 veterans performed significantly worse on letter and category fluency relative to Syndrome 1 veterans and controls. They also exhibited reduced activity in the thalamus, putamen, and amygdala, and increased activity in the right hippocampus relative to controls. Syndrome 1 and Syndrome 3 groups tended to show similar, although smaller, differences than the Syndrome 2 group. Hence, these results further demonstrate specific impairments in complex language as well as subcortical and hippocampal involvement in Syndrome 2 veterans. Further research is required to determine the extent of language impairments in this population and the significance of altered neurologic activity in the aforementioned brain regions with the purpose of better characterizing the Gulf War Syndromes.

Central Executive Dysfunction and Deferred Prefrontal Processing in Veterans with Gulf War Illness

Gulf War Illness is associated with toxic exposure to cholinergic disruptive chemicals. The cholinergic system has been shown to mediate the central executive of working memory (WM). The current work proposes that impairment of the cholinergic system in Gulf War Illness patients (GWIPs) leads to behavioral and neural deficits of the central executive of WM. A large sample of GWIPs and matched controls (MCs) underwent functional magnetic resonance imaging during a varied-load working memory task. Compared to MCs, GWIPs showed a greater decline in performance as WM-demand increased. Functional imaging suggested that GWIPs evinced separate processing strategies, deferring prefrontal cortex activity from encoding to retrieval for high demand conditions. Greater activity during high-demand encoding predicted greater WM performance. Behavioral data suggest that WM executive strategies are impaired in GWIPs. Functional data further support this hypothesis and suggest that GWIPs utilize less effective strategies during high-demand WM.

Methods for measuring serum activity levels of the 192 Q and R isoenzymes of paraoxonase 1 in QR heterozygous individuals

BACKGROUND

Paraoxonase 1 (PON1), an esterase that hydrolyzes toxic organophosphates and has antioxidative and antiatherogenic properties, contains a common polymorphism at position 192: glutamine (Q) or arginine (R). The Q and R isoenzymes exhibit different physical and protective properties. We describe 2 methods for quantifying their serum activity levels.

METHODS

We measured serum hydrolytic activity with paraoxon [paraoxonase (PXN) activity], phenylacetate [arylesterase (AE) activity], and diazoxon [diazoxonase (DZN) activity] with standard automated assays. We determined PON1 Q192R genotypes with PCR and Q192R phenotypes using the PXN/AE and PXN/DZN ratios. Interpolation equations were empirically derived to predict the percentage of total PON1 hydrolytic activity due to the Q isoenzyme (%Q) from the PXN/AE and PXN/DZN ratios; %R is 100 - %Q. We estimated Q and R isoenzyme activity levels in sera from 2095 veterans by multiplying AE activity, a measure of total PON1 hydrolytic activity, by %Q and %R.

RESULTS

In all 2095 samples, the PXN/AE and PXN/DZN ratios predicted Q192R phenotypes with nearly identical accuracy (κ = 0.997). In the 925 QR heterozygotes, the 2 interpolation methods predicted Q and R isoenzyme activity levels with excellent agreement (intraclass correlation 0.94). After excluding a few genotype/phenotype-discordant samples, the percentage of total PON1 activity due to the Q isoenzyme ranged from 22% to 70%.

CONCLUSIONS

These new interpolation methods allow accurate estimation of PON1 192 Q and R isoenzyme activity levels, increasing specificity and power for studying susceptibility to disease.

The 2012 West Nile encephalitis epidemic in Dallas, Texas

IMPORTANCE

After progressive declines over recent years, in 2012 West Nile virus epidemics resurged nationwide, with the greatest number of cases centered in Dallas County, Texas.

OBJECTIVE

To analyze the epidemiologic, meteorologic, and geospatial features of the 2012 Dallas West Nile virus epidemic to guide future prevention efforts.

DESIGN, SETTING, AND PATIENTS

Public health surveillance of Dallas County, an area of 2257 km2 and population of 2.4 million. Surveillance data included numbers of residents diagnosed with West Nile virus infection between May 30, 2012, and December 3, 2012; mosquito trap results; weather data; and syndromic surveillance from area emergency departments.

MAIN OUTCOMES AND MEASURES

Incidence and age-adjusted incidence rates of West Nile neuroinvasive disease (WNND), daily prevalence of emergency department visits for asthma and skin rash, and Culex quinquefasciatus species-specific vector index (an estimate of the average number of West Nile virus-infected mosquitoes per trap-night).

RESULTS

The investigation identified 173 cases of WNND, 225 of West Nile fever, 17 West Nile virus-positive blood donors, and 19 deaths in 2012. The incidence rate for WNND was 7.30 per 100,000 residents in 2012, compared with 2.91 per 100,000 in 2006, the largest previous Dallas County outbreak. An unusually rapid and early escalation of large numbers of human cases closely followed increasing infection trends in mosquitoes. The Cx quinquefasciatus species-specific vector index predicted the onset of symptoms among WNND cases 1 to 2 weeks later (count regression β = 2.97 [95% CI, 2.34 to 3.60]; P < .001). Although initially widely distributed, WNND cases soon clustered in neighborhoods with high housing density in the north central area of the county, reflecting higher vector indices and following geospatial patterns of West Nile virus in prior years. During the 11 years since West Nile virus was first identified in Dallas, the log-transformed annual prevalence of WNND was inversely associated with the number of days with low temperatures below 28°F (-2.2°C) in December through February (β = -0.29 [95% CI, -0.36 to -0.21]; P < .001). Aerial insecticide spraying was not associated with increases in emergency department visits for respiratory symptoms (β = -4.03 [95% CI, -13.76 to 5.70]; P = .42) or skin rash (β = -1.00 [95% CI, -6.92 to 4.92]; P = .74).

CONCLUSIONS AND RELEVANCE

Large West Nile virus epidemics in Dallas County begin early after unusually warm winters, revisit similar geographical distributions, and are strongly predicted by the mosquito vector index. Consideration of weather patterns and historical geographical hot spots and acting on the vector index may help prevent West Nile virus-associated illness.

Anteroposterior perfusion heterogeneity in human hippocampus measured by arterial spin labeling MRI

Measurements of blood flow in the human hippocampus are complicated by its relatively small size, unusual anatomy and patterns of blood supply. Only a handful of arterial spin labeling (ASL) MRI articles have reported regional cerebral blood flow (rCBF) values for the human hippocampus. Numerous reports have found heterogeneity in a number of other physiological and biochemical parameters along the longitudinal hippocampal axis. There is, however, only one ASL study of perfusion properties as a function of anteroposterior location in the hippocampus, reporting that rCBF is lower and the arterial transit time (ATT) is longer in the anterior hippocampus than in the posterior hippocampus of the rat brain. The purpose of this article was to measure ATT and rCBF in anterior, middle and posterior normal adult human hippocampus. To better distinguish anteroposterior perfusion heterogeneity in the hippocampus, a modified ASL method, called Orthogonally Positioned Tagging Imaging Method for Arterial Labeling with Flow-sensitive Alternating Inversion Recovery (OPTIMAL FAIR), was developed that provides high in-plane resolution with oblique coronal imaging slices perpendicular to the long axis of the hippocampus to minimize partial volume effects. Perfusion studies performed with this modified FAIR method at 3 T indicated that anterior, middle and posterior human hippocampus segments have unique transit time and rCBF values. Of these three longitudinal hippocampal regions, the middle hippocampus has the highest perfusion and the shortest transit time and the anterior hippocampus has the lowest perfusion and the longest transit time. Copyright © 2013 John Wiley & Sons, Ltd.

Meteorological and intelligence evidence of long-distance transit of chemical weapons fallout from bombing early in the 1991 Persian Gulf War

BACKGROUND

Coalition bombings on the night of 18-19 January 1991, early in the Gulf War, targeted the Iraqi chemical weapons infrastructure. On 19 January 1991, nerve agent alarms sounded within Coalition positions hundreds of kilometers to the south, and the trace presence of sarin vapor was identified by multiple technologies. Considering only surface dispersion of plumes from explosions, officials concluded that the absence of casualties around bombed sites precluded long-distance transit of debris to US troop positions to explain the alarms and detections. Consequently, they were discounted as false positives, and low-level nerve agent exposure early in the air war was disregarded in epidemiologic investigations of chronic illnesses.

INTELLIGENCE DATA

Newly assembled evidence indicates that plumes from those nighttime bombings of Iraqi chemical facilities would have traversed the stable nocturnal boundary layer and penetrated the residual layer where they would be susceptible to rapid transit by supergeostrophic winds. This explanation is supported by plume height predictions, available weather charts, weather satellite images showing transit of a hot air mass, effects of solar mixing of atmospheric layers, and observations of a stationary weather front and thermal inversion in the region.

CONCLUSIONS

Current evidence supports long-distance transit. Epidemiologic studies of chronic postwar illness should be reassessed using veterans' reports of hearing nerve agent alarms as the measure of exposure.

Event-related potential patterns associated with hyperarousal in Gulf War illness syndrome groups

An exaggerated response to emotional stimuli is one of the several symptoms widely reported by veterans of the 1991 Persian Gulf War. Many have attributed these symptoms to post-war stress; others have attributed the symptoms to deployment-related exposures and associated damage to cholinergic, dopaminergic, and white matter systems. We collected event-related potential (ERP) data from 20 veterans meeting Haley criteria for Gulf War Syndromes 1-3 and from 8 matched Gulf War veteran controls, who were deployed but not symptomatic, while they performed an auditory three-condition oddball task with gunshot and lion roar sounds as the distractor stimuli. Reports of hyperarousal from the ill veterans were significantly greater than those from the control veterans; different ERP profiles emerged to account for their hyperarousability. Syndromes 2 and 3, who have previously shown brainstem abnormalities, show significantly stronger auditory P1 amplitudes, purported to indicate compromised cholinergic inhibitory gating in the reticular activating system. Syndromes 1 and 2, who have previously shown basal ganglia dysfunction, show significantly weaker P3a response to distractor stimuli, purported to indicate dysfunction of the dopaminergic contribution to their ability to inhibit distraction by irrelevant stimuli. All three syndrome groups showed an attenuated P3b to target stimuli, which could be secondary to both cholinergic and dopaminergic contributions or disruption of white matter integrity.

Validation of a research case definition of Gulf War illness in the 1991 US military population

BACKGROUND

A case definition of Gulf War illness with 3 primary variants, previously developed by factor analysis of symptoms in a US Navy construction battalion and validated in clinic veterans, identified ill veterans with objective abnormalities of brain function. This study tests prestated hypotheses of its external validity.

METHODS

A stratified probability sample (n = 8,020), selected from a sampling frame of the 3.5 million Gulf War era US military veterans, completed a computer-assisted telephone interview survey. Application of the prior factor weights to the subjects' responses generated the case definition.

RESULTS

The structural equation model of the case definition fit both random halves of the population sample well (root mean-square error of approximation = 0.015). The overall case definition was 3.87 times (95% confidence interval, 2.61-5.74) more prevalent in the deployed than the deployable nondeployed veterans: 3.33 (1.10-10.10) for syndrome variant 1; 5.11 (2.43-10.75) for variant 2, and 4.25 (2.33-7.74) for variant 3. Functional status on SF-12 was greatly reduced (effect sizes, 1.0-2.0) in veterans meeting the overall and variant case definitions.

CONCLUSIONS

The factor case definition applies to the full Gulf War veteran population and has good characteristics for research.

Hippocampal dysfunction in Gulf War veterans: investigation with ASL perfusion MR imaging and physostigmine challenge

PURPOSE

To determine, with arterial spin labeling (ASL) perfusion magnetic resonance (MR) imaging and physostigmine challenge, if abnormal hippocampal blood flow in ill Gulf War veterans persists 11 years after initial testing with single photon emission computed tomography and nearly 20 years after the 1991 Gulf War.

MATERIALS AND METHODS

The local institutional review board approved this HIPAA-compliant study. Veterans were screened for contraindications and gave written informed consent before the study. In a semiblinded retrospective protocol, veterans in three Gulf War illness groups-syndrome 1 (impaired cognition), syndrome 2 (confusion-ataxia), and syndrome 3 (central neuropathic pain)-and a control group received intravenous infusions of saline in an initial session and physostigmine in a second session, 48 hours later. Each infusion was followed by measurement of hippocampal regional cerebral blood flow (rCBF) with pulsed ASL. A mixed-effects linear model adjusted for age was used to test for differences in rCBF after the cholinergic challenge across the four groups.

RESULTS

Physostigmine significantly decreased hippocampal rCBF in control subjects (P < .0005) and veterans with syndrome 1 (P < .05) but significantly increased hippocampal rCBF in veterans with syndrome 2 (P < .005) and veterans with syndrome 3 (P < .002). The abnormal increase in rCBF was found to have progressed to the left hippocampus of the veterans with syndrome 2 and to both hippocampi of the veterans with syndrome 3.

CONCLUSION

Chronic hippocampal perfusion dysfunction persists or worsens in veterans with certain Gulf War syndromes. ASL MR imaging examination of hippocampal rCBF in a cholinergic challenge experiment may be useful as a diagnostic test for this condition.

Improved quantification of brain perfusion using FAIR with active suppression of superior tagging (FAIR ASST)

PURPOSE

To address two problems for perfusion studies in the middle or inferior brain regions: (1) to reduce venous artifacts due to the intrinsic superior labeling of FAIR; (2) to alleviate the discrepancy of the existence of both superior and inferior boluses, but with only the inferior bolus having a temporally defined bolus width with Q2TIPs or QUIPSS.

MATERIALS AND METHODS

Superior tagging suppression methods for FAIR with different combinations of pre- and postinversion superior saturation pulses were evaluated and compared with FAIR with Q2TIPS for producing perfusion maps of superior, middle, and inferior brain regions.

RESULTS

One preinversion plus two postinversion superior saturation radio frequency pulses effectively suppressed the superior tagging of FAIR and sufficiently eliminated venous artifacts without negative effects, avoiding the overestimations of cerebral blood flow that can occur in FAIR.

CONCLUSION

FAIR ASST improves FAIR with Q2TIPS and provides more reliable and accurate blood flow estimations for perfusion studies of middle and lower brain regions. FAIR ASST confers the advantages of asymmetric PASL techniques, such as PICORE, in which only the inferiorly labeled blood is used for perfusion quantification, to the symmetric PASL technique FAIR, while preserving the robustness of FAIR against MT effects.

Epidemiological similarities between appendicitis and diverticulitis suggesting a common underlying pathogenesis

BACKGROUND

Nonperforating appendicitis is primarily a disease of children, and nonperforating diverticulitis affects mostly older adults. Apart from these age differences, the diseases share many epidemiological features, such as association with better hygiene and low-fiber diets.

HYPOTHESIS

Nonperforating appendicitis and nonperforating diverticulitis are different manifestations of the same underlying colonic process and, if so, should be temporally related.

DESIGN

Data from the National Hospital Discharge Survey were analyzed to investigate the incidence of admissions for appendicitis in children and diverticulitis in adults between 1979 and 2006.

SETTING

Statistical sampling of all US hospitals.

PATIENTS

Children admitted for appendicitis and adults with diverticulitis.

MAIN OUTCOME MEASURES

Time trends were assessed for stationarity using unit root analysis, and similarities between time trends were tested using cointegration analysis.

RESULTS

The incidence rates of nonperforating appendicitis and nonperforating diverticulitis exhibited U-shaped secular trends. The rates of perforating appendicitis and perforating diverticulitis rose slowly across all the study years. Cointegration analysis demonstrated that the rates of nonperforating and perforating diverticulitis did not cointegrate significantly over time. The rates of nonperforating and perforating appendicitis did not vary together. Nonperforating appendicitis and nonperforating diverticulitis rates were significantly cointegrated over time.

CONCLUSIONS

Childhood appendicitis and adult diverticulitis seem to be similar diseases, suggesting a common underlying pathogenesis. Secular trends for their nonperforating and perforating forms are strikingly different. At least for appendicitis, perforating disease may not be an inevitable outcome from delayed treatment of nonperforating disease. If appendicitis represents the same pathophysiologic process as diverticulitis, it may be amenable to antibiotic rather than surgical treatment.

Perfusion deficit to cholinergic challenge in veterans with Gulf War Illness

A highly plausible etiology for Gulf War Illness (GWI) is that the neural damage and cognitive deficits are associated with excessive exposure to cholinesterase-inhibiting cholinergic stimulants. Our previous SPECT study provided strong indication that cerebral blood flow (CBF) in veterans with GWI may be different from those of unaffected control veterans. The present study confirmed and extended previous findings that patients with GWI have abnormal response to an inhibitory cholinergic challenge, physostigmine infusion, when compared to age-gender-education matched control veterans. The MRI-based arterial spin labeling (ASL) and phase-contrast techniques have several key advantages over SPECT, including shorter experiment duration, complete non-invasiveness, and higher spatial and temporal resolutions, and therefore may provide a cost-effective biomarker for characterization of GWI.

Effectiveness of a barber-based intervention for improving hypertension control in black men: the BARBER-1 study: a cluster randomized trial

BACKGROUND

Barbershop-based hypertension (HTN) outreach programs for black men are becoming increasingly common, but whether they are an effective approach for improving HTN control remains uncertain.

METHODS

To evaluate whether a continuous high blood pressure (BP) monitoring and referral program conducted by barbers motivates male patrons with elevated BP to pursue physician follow-up, leading to improved HTN control, a cluster randomized trial (BARBER-1) of HTN control was conducted among black male patrons of 17 black-owned barbershops in Dallas County, Texas (March 2006-December 2008). Participants underwent 10-week baseline BP screening, and then study sites were randomized to a comparison group that received standard BP pamphlets (8 shops, 77 hypertensive patrons per shop) or an intervention group in which barbers continually offered BP checks with haircuts and promoted physician follow-up with sex-specific peer-based health messaging (9 shops, 75 hypertensive patrons per shop). After 10 months, follow-up data were obtained. The primary outcome measure was change in HTN control rate for each barbershop.

RESULTS

The HTN control rate increased more in intervention barbershops than in comparison barbershops (absolute group difference, 8.8% [95% confidence interval (CI), 0.8%-16.9%]) (P = .04); the intervention effect persisted after adjustment for covariates (P = .03). A marginal intervention effect was found for systolic BP change (absolute group difference, -2.5 mm Hg [95% CI, -5.3 to 0.3 mm Hg]) (P = .08).

CONCLUSIONS

The effect of BP screening on HTN control among black male barbershop patrons was improved when barbers were enabled to become health educators, monitor BP, and promote physician follow-up. Further research is warranted.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00325533.

Impaired response inhibition in ill Gulf War veterans

Poor performance on tasks requiring response inhibition has been observed among chronically ill veterans of the 1991 Persian Gulf War. Semantic difficulties have also been reported. We collected event-related potential (ERP) and behavioral data from 25 Gulf War veterans who complained of cognitive difficulties and from 23 matched controls, who were deployed but not symptomatic, while they performed a GO-NOGO task that required both a semantic decision and inhibitory processing. A significantly greater false-alarm rate among the ill veterans was accompanied in the ERP data by significantly reduced amplitude in the NOGO P3, consistent with previous ERP studies of other patient groups that have shown poor inhibitory response performance. This supports the contention that the ill veterans' deficit lies more in inhibiting than in detecting task-related differences in the stimuli.

Association of viral infection and appendicitis

HYPOTHESIS

What causes appendicitis is not known; however, studies have suggested a relationship between viral diseases and appendicitis. Building on evidence of cyclic patterns of appendicitis with apparent outbreaks consistent with an infectious etiology, we hypothesized that there is a relationship between population rates of appendicitis and several infectious diseases.

DESIGN

Epidemiologic study.

SETTING

The National Hospital Discharge Survey

PATIENTS

Estimated US hospitalized population.

MAIN OUTCOME MEASURES

International Classification of Diseases, Ninth Revision, Clinical Modification discharge diagnosis codes of the National Hospital Discharge Survey were queried from 1970 to 2006 to identify admissions for appendicitis, influenza, rotavirus, and enteric infections. Cointegration analysis of time series data was used to determine if the disease incidence trends for these various disease entities varied over time together.

RESULTS

Rates of influenza and nonperforating appendicitis declined progressively from the late 1970s to 1995 and rose thereafter, but influenza rates exhibited more distinct seasonal variation than appendicitis rates. Rotavirus infection showed no association with the incidence of nonperforating appendicitis. Perforating appendicitis showed a dissimilar trend to both nonperforating appendicitis and viral infection. Hospital admissions for enteric infections substantially increased over the years but were not related to appendicitis cases.

CONCLUSIONS

Neither influenza nor rotavirus are likely proximate causes of appendicitis given the lack of a seasonal relationship between these disease entities. However, because of significant cointegration between the annual incidence rates of influenza and nonperforated appendicitis, it is possible that these diseases share common etiologic determinates, pathogenetic mechanisms, or environmental factors that similarly affect their incidence.

Distinct autoimmune syndromes in morphea: a review of 245 adult and pediatric cases

OBJECTIVE

To determine the prevalence of extracutaneous manifestations and autoimmunity in adult and pediatric patients with morphea.

DESIGN

A retrospective review of 245 patients with morphea.

SETTING

University of Texas Southwestern Medical Center-affiliated institutions. Patients Patients with clinical findings consistent with morphea.

MAIN OUTCOME MEASURES

Prevalence of concomitant autoimmune diseases, prevalence of familial autoimmune disease, prevalence of extracutaneous manifestations, and laboratory evidence of autoimmunity (antinuclear antibody positivity). Secondary outcome measures included demographic features.

RESULTS

In this group, adults and children were affected nearly equally, and African Americans were affected less frequently than expected. The prevalence of concomitant autoimmunity in the generalized subtype of morphea was statistically significantly greater than that found in all other subtypes combined (P = .01). Frequency of a family history of autoimmune disease showed a trend in favor of generalized and mixed subgroups. The linear subtype showed a significant association with neurologic manifestations, while general systemic manifestations were most common in the generalized subtype. Antinuclear antibody positivity was most frequent in mixed and generalized subtypes.

CONCLUSIONS

High prevalences of concomitant and familial autoimmune disease, systemic manifestations, and antinuclear antibody positivity in the generalized and possibly mixed subtypes suggest that these are systemic autoimmune syndromes and not skin-only phenomena. This has implications for the management and treatment of patients with morphea.

Abnormal brain response to cholinergic challenge in chronic encephalopathy from the 1991 Gulf War

Several case definitions of chronic illness in veterans of the 1991 Persian Gulf War have been linked epidemiologically with environmental exposure to cholinesterase-inhibiting chemicals, which cause chronic changes in cholinergic receptors in animal models. Twenty-one chronically ill Gulf War veterans (5 with symptom complex 1, 11 with complex 2, and 5 with complex 3) and 17 age-, sex- and education-matched controls, underwent an 99mTc-HMPAO-SPECT brain scan following infusion of saline and >48 h later a second scan following infusion of physostigmine in saline. From each SPECT image mean normalized regional cerebral blood flow (nrCBF) from 39 small blocks of correlated voxels were extracted with geostatistical spatial modeling from eight deep gray matter structures in each hemisphere. Baseline nrCBF in symptom complex 2 was lower than controls throughout deep structures. The change in nrCBF after physostigmine (challenge minus baseline) was negative in complexes 1 and 3 and controls but positive in complex 2 in some structures. Since effects were opposite in different groups, no finding typified the entire patient sample. A hold-out discriminant model of nrCBF from 17 deep brain blocks predicted membership in the clinical groups with sensitivity of 0.95 and specificity of 0.82. Gulf War-associated chronic encephalopathy in a subset of veterans may be due to neuronal dysfunction, including abnormal cholinergic response, in deep brain structures.