Thiamine as a metabolic resuscitator after in-hospital cardiac arrest

INTRODUCTION

Elevated lactate is associated with mortality after cardiac arrest. Thiamine, a cofactor of pyruvate dehydrogenase, is necessary for aerobic metabolism. In a mouse model of cardiac arrest, thiamine improved pyruvate dehydrogenase activity, survival and neurologic outcome.

AIM

To determine if thiamine would decrease lactate and increase oxygen consumption after in-hospital cardiac arrest.

METHODS

Randomized, double-blind, placebo-controlled phase II trial. Adult patients with arrest within 12 hours, mechanically ventilated, with lactate ≥ 3 mmol/L were included. Randomization was stratified by lactate > 5 or ≤ 5 mmol/L. Thiamine 500 mg or placebo was administered every 12 hours for 3 days. The primary outcome of lactate was checked at baseline, 6, 12, 24, and 48 hours, and compared using a linear mixed model, accounting for repeated measures. Secondary outcomes included oxygen consumption, pyruvate dehydrogenase, and mortality.

RESULTS

Enrollments stopped after 36 patients due Data Safety and Monitoring Board concern about potential harm in an unplanned subgroup analysis. There was no overall difference in lactate (mean difference at 48 hours 1.5 mmol/L [95% CI -3.1-6.1], global p = 0.88) or any secondary outcomes. In those with randomization lactate > 5 mmol/L, mortality was 92% (11/12) with thiamine and 67% (8/12) with placebo (p = 0.32). In those with randomization lactate ≤ 5 mmol/L mortality was 17% (1/6) with thiamine and 67% (4/6) with placebo (p = 0.24). There was a significant interaction between randomization lactate and the effect of thiamine on survival (p = 0.03).

CONCLUSIONS

In this single center trial thiamine had no overall effect on lactate after in-hospital cardiac arrest.

Thiamine as a metabolic resuscitator after out-of-hospital cardiac arrest

INTRODUCTION

Thiamine is a key cofactor for aerobic metabolism, previously shown to improve mortality and neurological outcomes in a mouse model of cardiac arrest. We hypothesized that thiamine would decrease lactate and improve outcomes in post-arrest patients.

METHODS

Single center, randomized, blinded, placebo-controlled, Phase II trial of thiamine in adults within 4.5 hours of return of spontaneous circulation after out-of-hospital cardiac arrest (OHCA), with coma and lactate ≥ 3 mmol/L. Participants received 500 mg IV thiamine or placebo twice daily for 2 days. Randomization was stratified by lactate > 5 or ≤ 5 mmol/L. The primary outcome of lactate was checked at baseline, 6, 12, and 24 hours, and compared using a linear mixed model to account for repeated measures. Secondary outcomes included SOFA score, pyruvate dehydrogenase, renal injury, neurological outcome, and mortality.

RESULTS

Of 93 randomized patients, 76 were enrolled and included in the analysis. There was no difference in lactate over 24 hours (mean difference 0.34 mmol/L (95% CI: -1.82, 2.50), p = 0.43). There was a significant interaction between randomization lactate subgroup and the effect of the intervention on mortality (p = 0.01) such that mortality was higher with thiamine in the lactate > 5 mmol/L group and lower with thiamine in the < 5 mmol/L group. This subgroup difference prompted the Data and Safety Monitoring Board to recommend the study be terminated early. PDH activity increased over 72 hours in the thiamine group. There were no differences in other secondary outcomes.

CONCLUSION

In this single-center randomized trial, thiamine did not affect lactate over 24 hours after OHCA.

Tar pollution event (2021) at the Southeastern Levantine oligotrophic basin, short-term impacts and operational oceanography perspectives

The Levantine basin (LB) in the Southeastern Mediterranean Sea is a high-risk oil pollution hot spot owing to its dense maritime traffic and intense oil and gas exploration and exploitation activities. In February 2021 the Israeli LB shorelines were impacted by an exceptional tar pollution event (~550 tons; average distribution: ~3 kg tar m-1 front beach) of an unknown oil spill source. Here we report on the immediate numerical modelling assessment of the oil spill propagation and tar distribution; operational use of underwater gliders for tracking water column anomalies of dissolved polycyclic aromatic hydrocarbons (PAHs) and turbidity signals; the beached tar composition and amounts and the short-term response of the microbial population along the ~180 km shoreline. This pollution event emphasizes the need for improving the early warning systems for oil spills and implementing continuous operational monitoring at high-risk, ecologically sensitive and valuable resource areas like the Israeli LB waters.

Body Mass Index Is Associated With Myocutaneous Free Flap Reliability: Overcoming the Obesity Obstacle With a Proposed Clinical Algorithm to Identify and Manage High-Risk Patients Undergoing Gracilis Free Flap With Skin Paddle Harvest

INTRODUCTION

The purpose of this study was to evaluate the role of body mass index (BMI) in predicting postoperative complications following myocutaneous free flap transfer. In addition, we sought to identify certain body composition variables that may be used to stratify patients into low- versus high-risk for gracilis myocutaneous free flap with skin paddle failure.

METHODS

Using the National Surgical Quality Improvement Program database, we collected data for all patients who underwent myocutaneous free flap transfer from 2015 to 2021. Demographic data, medical history, surgical characteristics, and postoperative outcomes, including complications, reoperations, and readmissions, were collected. Body mass index was correlated with outcome measures to determine its role in predicting myocutaneous free flap reliability. Subsequently, we retrospectively obtained measurements of perigracilis anatomy in patients who underwent computed tomography angiography bilateral lower extremity scans with intravenous contrast at our institution. We compared body composition data with mathematical equations calculating the potential area along the skin of the thigh within which the gracilis perforator may be found.

RESULTS

Across the United States, 1549 patients underwent myocutaneous free flap transfer over the 7-year study period. Being in obesity class III (BMI ≥40 kg/m2) was associated with a 4-times greater risk of flap complications necessitating a return to the operating room compared with being within the normal BMI range. In our computed tomography angiography analysis, average perigracilis adipose thickness was 18.3 ± 8.0 mm. Adipose thickness had a strong, positive exponential relationship with the area of skin within which the perforator may be found.

CONCLUSIONS

In our study, higher BMI was associated with decreased myocutaneous free flap reliability. Specifically, inner thigh adipose thickness can be used to estimate the area along the skin within which the gracilis perforator may be found. This variable, along with BMI, can be used to identify patients who are considered high-risk for flap failure and who may benefit from additional postoperative monitoring, such as the use of a color flow Doppler probe and more frequent and prolonged skin paddle monitoring.

Change in Pain-Related Anxiety Mediates the Effects of Psychophysiologic Symptom Relief Therapy (PSRT) on Pain Disability for Chronic Back Pain: Secondary Results from a Randomized Controlled Trial

Purpose

Widely used therapeutic approaches, such as cognitive-behavioral and mindfulness-based therapies, can improve pain and functioning in people with chronic back pain, but the magnitude and duration of their effects are limited. Our team developed a novel 12-week program, psychophysiologic symptom relief therapy (PSRT), to substantially reduce or eliminate pain and disability. This study examined whether PSRT helped more patients achieve large-magnitude (≥30%, ≥50%, ≥75%) reductions in back pain-related disability compared to mindfulness-based stress reduction (MBSR) and usual care (UC), and if the beneficial effects of PSRT were explained by reductions in pain-related anxiety following treatment.

Patients and Methods

Data from a three-armed randomized controlled trial were used (N=35 adults with chronic back pain). Change scores (baseline to 4-, 8-, 13-, and 26-weeks post-enrollment) were computed for back pain disability (RDQ) and pain-related anxiety (PASS-20). Fisher's exact tests and mediation analyses were conducted.

Results

Compared to MBSR and UC, PSRT helped significantly more patients achieve ≥75% reductions in back pain disability at all timepoints and in pain anxiety at all timepoints except 13-weeks. Change in pain anxiety significantly mediated the relationship between treatment group and change in back pain disability from baseline to 26-weeks.

Conclusion

PSRT helped more patients achieve substantial reductions in disability than an established treatment (MBSR) and usual care. Findings indicate reduced pain anxiety may be a mechanism by which PSRT confers long-term benefits on disability. Importantly, this work aims to move the field toward more precise and effective treatment for chronic back pain.

Kidney-specific biomarkers for predicting acute kidney injury following cardiac arrest

AIM

To evaluate the performance of kidney-specific biomarkers (neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and cystatin-C) in early detection of acute kidney injury (AKI) following cardiac arrest (CA) when compared to serum creatinine.

METHODS

Adult CA patients who had kidney-specific biomarkers of AKI collected within 12 h of return of spontaneous circulation (ROSC) were included. The association between renal biomarker levels post-ROSC and the development of KDIGO stage III AKI within 7 days of enrollment were assessed as well as their predictive value of future AKI development, neurological outcomes, and survival to discharge.

RESULTS

Of 153 patients, 54 (35%) developed stage III AKI within 7 days, and 98 (64%) died prior to hospital discharge. Patients who developed stage III AKI, compared to those who did not, had higher median levels of creatinine, NGAL, and cystatin-C (p < 0.001 for all). There was no statistically significant difference in KIM-1 between groups. No biomarker outperformed creatinine in the ability to predict stage III AKI, neurological outcomes, or survival outcomes (p > 0.05 for all). However, NGAL, cystatin-C, and creatinine all performed better than KIM-1 in their ability to predict AKI development (p < 0.01 for all).

CONCLUSION

In post-CA patients, creatinine, NGAL, and cystatin-C (but not KIM-1) measured shortly after ROSC were higher in patients who subsequently developed AKI. No biomarker was statistically superior to creatinine on its own for predicting the development of post-arrest AKI.

Psychophysiologic Symptom Relief Therapy (PSRT) for Post-acute Sequelae of COVID-19

Objective

To determine if psychophysiologic symptom relief therapy (PSRT) will reduce symptom burden in patients suffering from post-acute sequelae of COVID-19 (PASC) who had mild/moderate acute COVID-19 disease without objective evidence of organ injury.

Patients and Methods

Twenty-three adults under the age of 60 with PASC for at least 12 weeks following COVID-19 infection were enrolled in an interventional cohort study conducted via virtual platform between May 18, 2021 and August 7, 2022. Participants received PSRT during a 13 week (approximately 44 hour) course. Participants were administered validated questionnaires at baseline and at 4, 8, and 13 weeks. The primary outcome was change in somatic symptoms from baseline, measured using the Somatic Symptom Scale-8 (SSS-8), at 13 weeks.

Results

The median duration of symptoms prior to joining the study was 267 days (IQR: 144, 460). The mean SSS-8 score of the cohort decreased from baseline by 8.5 (95% CI: 5.7-11.4), 9.4 (95% CI: 6.9-11.9), and 10.9 (95% CI: 8.3-13.5) at 4, 8, and 13 weeks respectively (all p<.001). Participants also experienced statistically significant improvements across other secondary outcomes including changes in dyspnea, fatigue, and pain (all p<.001).

Conclusion

PSRT may effectively decrease symptom burden in patients suffering from PASC without evidence of organ injury. The study was registered on clinicaltrials.gov (NCT04854772).

A220 AN UNEXPECTED CAUSE OF ACUTE JAUNDICE IN A POST-TRANSPLANT PATIENT

Background

Complications post liver transplantation are common. These may include thromboses, primary graft nonfunction, biliary complications, chylothorax, infection, and rejection. Hepaticojejunostomy with Roux-en-Y limb is a common technique for pediatric liver transplantation. Complications of hepaticojejunostomy include small bowel obstruction due to incarceration of the Roux-en-Y limb within an internal hernia. Acquired diaphragmatic hernia has previously been reported in liver transplant patients. Here we present a unique case of acute biliary obstruction secondary to incarceration of a Roux limb within an acquired diaphragmatic hernia.

Aims

To describe a unique case of incarcerated Roux-en-Y limb in a diaphragmatic hernia leading to acute jaundice in a pediatric liver transplant patient.

Methods

Retrospective chart review and case review with the surgical and medical teams.

Results

A 14 month old girl with unresectable hepatoblastoma received a living donor, left lateral segment liver transplant using standard venous reconstruction, microvascular plastics arterial reconstruction, and the recipient common hepatic duct was anastomosed to the donor left hepatic duct. Serial ultrasounds showed persistent intrahepatic duct dilatation with cholestasis. Given the concern of biliary obstruction, 10 days post-transplant, she underwent repeat laparotomy and was found to have a dilated common bile duct with a proximal obstruction. A Roux-en-Y hepaticojejunostomy was performed to establish adequate biliary drainage.

Three months post-transplant she developed lung metastases that required wedge resection and chemotherapy. 7 months post-transplant, while admitted for routine chemotherapy she acutely developed jaundice, pruritus, and transaminitis. Liver ultrasound showed an apparent fluid collection at the cut surface of the liver and biliary dilatation. Extrinsic compression of the biliary tree was suspected, and so a percutaneous biliary drain was placed to drain the collection and decompress the biliary system.

Despite improvement in the transaminitis and cholestasis, several days later, she developed severe abdominal pain and associated grunting respirations. An MRI with MRCP to reassess the previous findings and rule out a new intraabdominal cause for her symptoms was completed and unexpectedly showed herniation of her Roux-en-Y limb into a diaphragmatic hernia. She had urgent diaphragmatic hernia repair with reduction of the incarcerated bowel loop, with resolution of her pain and jaundice.

Conclusions

Post liver transplant Roux-en-Y herniation is uncommon, but can occur with internal hernias and in diaphragmatic hernias. This uncommon complication should be considered for the post liver transplant patient with hepaticojejunostomy in the setting of acute jaundice, particularly if accompanied by acute onset abdominal pain and/or increased work of breathing.

Funding Agencies

None

Legacy groundwater pollution as a source of mercury enrichment in marine food web, Haifa Bay, Israel

Haifa Bay (HB), located along the northern Mediterranean shore of Israel was polluted with Hg from a chlor-alkali plant (ECI) and from the Qishon River industries, for decades. From the mid-1980s industrial Hg loads into HB decreased dramatically until their complete cessation in 2000. Consequently, concentrations in marine biota and sediments decreased almost to reference levels. However, during 2006-2014, an unexpected increase of total Hg (THg) concentrations was observed in three commercial fish species collected at northern HB (N.HB). To determine the cause of this increase, THg and methyl Hg (MeHg) were measured in seawater, coastal groundwater, suspended particulate matter, plankton, macroalgae, benthic fauna, and in marine and beach sediments. THg in groundwater and sediments from the vicinity of ECI were extremely high (up to 251 μg L^-1 and 2200 ng g^-1, respectively). MeHg concentrations in groundwater were low and constituted <0.1% of THg, except in the surf zone opposite the ECI, where MeHg constituted 0.2% of the THg. THg and MeHg concentrations were consistently higher in benthic biota and plankton from N.HB and northwards, compared to corresponding samples from southern HB (S.HB) and the reference site (RS). MeHg in bivalves and sponges from N.HB and SZ was higher than from S.HB and RS, despite having similar THg concentrations, which suggests a stronger source of MeHg in N.HB. Our findings suggest that the discharge into N.HB of Hg polluted groundwater under the ECI increased during the period 2006-2014. The Hg was assimilated by plankton or adsorbed onto inorganic particles, which were further ingested by benthic and pelagic consumers, as well as transported northward with the alongshore current. These findings demonstrate for the first time the potential of relic pollution in groundwater to increase heavy metal burdens in local marine food webs.

A134 RATES OF PARENTERAL NUTRITION-ASSOCIATED CHOLESTASIS/LIVER DISEASE AND GROWTH PRE- AND POST-SMOFLIPID INTRODUCTION IN NEONATES AND INFANTS WITH INTESTINAL FAILURE

Background

Parenteral nutrition (PN) is essential for survival in infants with intestinal failure (IF). PN-associated cholestasis (PNAC) and liver disease (PNALD) are life-threatening complications of long-term PN use. SMOFlipid (soybean oil, medium-chain triglycerides, olive oil, and fish oil) has recently been approved as an off-label alternative to the conventional soy-based lipid emulsion (Intralipid). It is thought to have anti-cholestatic properties due to its more diverse lipid composition. Due to its’ recent approval in Canada (2013) and the USA (2016), data remains sparse.

Aims

We aim to determine if infants with IF receiving SMOFlipid had significantly lower rates of PNAC and improved growth compared to those receiving Intralipid.

Methods

All patients (≤1 year old at start of PN therapy) who received PN of any duration at two tertiary pediatric hospitals in Edmonton (2010–2018) were identified from the shared pharmacy database. Those with IF who received one type of PN continuously for ≥6 weeks total were included. Individuals with an initial serum conjugated bilirubin &gt;50 µmol/L and/or who had PN interruptions &gt;5 days were excluded. Data on liver parameters, growth, and complications were collected. Non-parametric tests (Mann-Whitney U test for continuous variables and χ2 test for categorical variables) were used to compare PNAC/PNALD (serum conjugated bilirubin &gt;34umol/L during PN) and growth (weight/length/head circumference z-scores) between SMOFlipid and Intralipid.

Results

1777 patients were reviewed; 40 infants (55% male), median age 4 weeks (range 0–48 weeks) at the time of PN initiation, met the inclusion criteria. Reasons for exclusion (n=1737) were receiving PN &lt;6 weeks total (n=1485), duplicate patients (n=154), receiving multiple types of PN with each less than 6 weeks total (n=62), an initial serum conjugated bilirubin &gt;50umol/L (n=21), more than 5 consecutive days off of PN (n=12), and older than 1 year old at time of PN initiation (n=3). Twenty-one patients (53%) received SMOFlipid, 15 (38%) Intralipid, and 4 (10%) Omegaven for ≥6 weeks. The majority (92%) were in an intensive care unit (neonatal or pediatric). No patients were septic when starting PN. Individuals received PN over a median of 7.9 weeks (range 6–27 weeks).

Conclusions

As expected, neonatal onset intestinal failure is rare in Edmonton. In our tertiary pediatric institutions, 2010–2018, SMOFLipid was the predominant lipid choice for infants with intestinal failure, followed by Intralipid. Omegaven was used rarely. This dataset will now allow us to compare the rates of PNAC at six weeks post-PN initiation and differences in growth between infants with IF receiving SMOFlipid versus the traditional Intralipid in our Canadian setting. Analysis is currently underway.

Funding Agencies

Women and Children’s Health Research Institute (WCHRI) at the University of Alberta

Haptoglobin 1-1 Genotype Modulates the Association of Glycemic Control With Hippocampal Volume in Elderly Individuals With Type 2 Diabetes

Recent evidence suggests that glycemic control is associated with cognitive function in older patients with type 2 diabetes who are carriers of the haptoglobin (Hp) 1-1 genotype compared with noncarriers. We assessed whether poor glycemic control in Hp 1-1 carriers is more strongly associated with smaller hippocampal volume than in noncarriers. Hippocampal volume was generated from high-resolution structural T1 MRI obtained for 224 participants (28 Hp 1-1 carriers [12.5%] and 196 noncarriers [87.5%]) from the Israel Diabetes and Cognitive Decline (IDCD) study, who had a mean (SD) number of years in the Maccabi Healthcare Services (MHS) registry of 8.35 (2.63) and a mean (SD) HbA_1c level of 6.66 (0.73)% [49 mmol/mol]. A stronger negative association between right hippocampal volume and HbA_1c was found in patients with the Hp 1-1 genotype, with a 0.032-mL decrease in right hippocampal volume per 14% increase in HbA_1c (P = 0.0007) versus a 0.009-mL decrease in Hp 1-1 noncarriers (P = 0.047), after adjusting for total intracranial volume, age, sex, follow-up years in the registry, and cardiovascular factor (interaction, P = 0.025). This indicates that 29.66% of the total variance in right hippocampal volume is explained by HbA_1c levels among Hp 1-1 carriers and that 3.22% is explained by HbA_1c levels among Hp 1-1 noncarriers. Our results suggest that the hippocampus of Hp 1-1 carriers may be more vulnerable to the insults of poor glycemic control.

Spatial distribution and sources of organic matter and pollutants in the SE Mediterranean (Levantine basin) deep water sediments

A study of deep sea sediment quality was conducted at 52 stations off the Mediterranean coast of Israel (50-1900m depth). Total Organic Carbon (TOC), Polycyclic Aromatic Hydrocarbons (∑PAHs), Poly Chlorinated Biphenyls (∑PCBs) ranged between 0.58 and 1.44%, 12-190 and <0.3-7.7μgkg^-1, respectively. The TOC distribution indicated the Nile delta as an important source of organic matter and the important effect of topography on deposition patterns in this region. PCBs and PAHs quantitative levels were associated with nearby gas well drilling (well below environmental criteria) and dredge-material dumping sites. A significant correlation between these pollutants and TOC was found in the southernmost stations suggesting a common source. PAHs isomer ratios in most of the stations indicated a petrogenic source, while the contribution of pyrogenic sources appears to be very small. These findings form a sound baseline for assessing the potential impact of future deep sea drilling activities that are expected to increase significantly in the Eastern Mediterranean basin.

Seizure-associated central apnea in a rat model: Evidence for resetting the respiratory rhythm and activation of the diving reflex

Respiratory derangements, including irregular, tachypnic breathing and central or obstructive apnea can be consequences of seizure activity in epilepsy patients and animal models. Periods of seizure-associated central apnea, defined as periods >1s with rapid onset and offset of no airflow during plethysmography, suggest that seizures spread to brainstem respiratory regions to disrupt breathing. We sought to characterize seizure-associated central apneic episodes as an indicator of seizure impact on the respiratory rhythm in rats anesthetized with urethane and given parenteral kainic acid to induce recurring seizures. We measured central apneic period onsets and offsets to determine if onset-offset relations were a consequence of 1) a reset of the respiratory rhythm, 2) a transient pausing of the respiratory rhythm, resuming from the pause point at the end of the apneic period, 3) a transient suppression of respiratory behavior with apnea offset predicted by a continuation of the breathing pattern preceding apnea, or 4) a random re-entry into the respiratory cycle. Animals were monitored with continuous ECG, EEG, and plethysmography. One hundred ninety central apnea episodes (1.04 to 36.18s, mean: 3.2±3.7s) were recorded during seizure activity from 7 rats with multiple apneic episodes. The majority of apneic period onsets occurred during expiration (125/161 apneic episodes, 78%). In either expiration or inspiration, apneic onsets tended to occur late in the cycle, i.e. between the time of the peak and end of expiration (82/125, 66%) or inspiration (34/36, 94%). Apneic period offsets were more uniformly distributed between early and late expiration (27%, 34%) and inspiration (16%, 23%). Differences between the respiratory phase at the onset of apnea and the corresponding offset phase varied widely, even within individual animals. Each central apneic episode was associated with a high frequency event in EEG or ECG records at onset. High frequency events that were not associated with flatline plethysmographs revealed a constant plethysmograph pattern within each animal, suggesting a clear reset of the respiratory rhythm. The respiratory rhythm became highly variable after about 1s, however, accounting for the unpredictability of the offset phase. The dissociation of respiratory rhythm reset from the cessation of airflow also suggested that central apneic periods involved activation of brainstem regions serving the diving reflex to eliminate the expression of respiratory movements. This conclusion was supported by the decreased heart rate as a function of apnea duration. We conclude that seizure-associated central apnea episodes are associated with 1) a reset of the respiratory rhythm, and 2) activation of brainstem regions serving the diving reflex to suppress respiratory behavior. The significance of these conclusions is that these details of seizure impact on brainstem circuitry represent metrics for assessing seizure spread and potentially subclassifying seizure patterns.

Laryngospasm, central and obstructive apnea during seizures: Defining pathophysiology for sudden death in a rat model

Seizure spread into the autonomic nervous system can result in life-threatening cardiovascular and respiratory dysfunction. Here we report on a less-studied consequence of such autonomic derangements-the possibility of laryngospasm and upper-airway occlusion. We used parenteral kainic acid to induce recurring seizures in urethane-anesthetized Sprague Dawley rats. EEG recordings and combinations of cardiopulmonary monitoring, including video laryngoscopy, were performed during multi-unit recordings of recurrent laryngeal nerve (RLN) activity or head-out plethysmography with or without endotracheal intubation. Controlled occlusions of a tracheal tube were used to study the kinetics of cardiac and respiratory changes after sudden obstruction. Seizure activity caused significant firing increases in the RLN that were associated with abnormal, high-frequency movements of the vocal folds. Partial airway obstruction from laryngospasm was evident in plethysmograms and was prevented by intubation. Complete glottic closure (confirmed by laryngoscopy) occurred in a subset of non-intubated animals in association with the largest increases in RLN activity, and cessation of airflow was followed in all obstructed animals within tens of seconds by ST-segment elevation, bradycardia, and death. Periods of central apnea occurred in both intubated and non-intubated rats during seizures for periods up to 33s and were associated with modestly increased RLN activity, minimal cardiac derangements, and an open airway on laryngoscopy. In controlled complete airway occlusions, respiratory effort to inspire progressively increased, then ceased, usually in less than 1min. Respiratory arrest was associated with left ventricular dilatation and eventual asystole, an elevation of systemic blood pressure, and complete glottic closure. Severe laryngospasm contributed to the seizure- and hypoxemia-induced conditions that resulted in sudden death in our rat model, and we suggest that this mechanism could contribute to sudden death in epilepsy.

A methanotroph-based biorefinery: Potential scenarios for generating multiple products from a single fermentation

Methane, a carbon source for methanotrophic bacteria, is the principal component of natural gas and is produced during anaerobic digestion of organic matter (biogas). Methanotrophs are a viable source of single cell protein (feed supplement) and can produce various products, since they accumulate osmolytes (e.g. ectoine, sucrose), phospholipids (potential biofuels) and biopolymers (polyhydroxybutyrate, glycogen), among others. Other cell components, such as surface layers, metal chelating proteins (methanobactin), enzymes (methane monooxygenase) or heterologous proteins hold promise as future products. Here, scenarios are presented where ectoine, polyhydroxybutyrate or protein G are synthesised as the primary product, in conjunction with a variety of ancillary products that could enhance process viability. Single or dual-stage processes and volumetric requirements for bioreactors are discussed, in terms of an annual biomass output of 1000 tonnesyear(-1). Product yields are discussed in relation to methane and oxygen consumption and organic waste generation.

Long-term Variability in Glycemic Control Is Associated With White Matter Hyperintensities in APOE4 Genotype Carriers With Type 2 Diabetes

OBJECTIVE

We assessed whether the apolipoprotein ε4 (APOE4) genotype affects the relationship of variability in long-term glycemic control (measured by HbA1c SD of multiple measurements) with white matter hyperintensities (WMHs) in elderly patients with type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

WMH volume was generated from structural T1 and fluid-attenuated inversion recovery MRI in each subject. The analysis included 124 subjects; 27 (21.8%) had one or more APOE4 alleles.

RESULTS

HbA1c variability was associated with significantly higher WMH in APOE4 carriers (r = 0.47, P = 0.03), controlling for age, sex, mean HbA1c, number of follow-up years, and a composite of cardiovascular risk factors, but not in noncarriers (r = -0.04, P = 0.71; P for interaction = 0.050).

CONCLUSIONS

The results suggest that the APOE4 genotype affects the relationship of long-term glycemic control with WMH load so that APOE4 carriers may be more vulnerable to the insults of poor control.

MP11: COMORBID DEPRESSION OR ANXIETY IS ASSOCIATED WITH AORTIC VASCULAR INFLAMMATION AND CORONARY HEART DISEASE BEYOND TRADITIONAL CARDIOVASCULAR RISK FACTORS IN PSORIASIS

Purpose of Study

Psoriasis is a chronic inflammatory disorder associated with vascular inflammation (VI), measured by 18-fluorodeoxyglucose positron emission tomography/computed tomography (18-FDG PET/CT), and increased risk of MI. Patients with psoriasis are more likely to have comorbid depression and anxiety. Whether these comorbidities accelerate the development of CVD in psoriasis is unclear. We hypothesized that aortic VI and coronary plaque burden would be increased in patients with psoriasis who have depression and/or anxiety compared to those with psoriasis who do not.

Methods Used

Patients were prospectively enrolled. Those who reported a history of depression and/or anxiety (n=40) on survey and age- and gender-matched patients who reported no history of psychiatric illness (n=40) were selected. Target-to-Background ratio from 18FDG PET/CT was used to assess aortic VI, and coronary CT angiography scans were analyzed for coronary plaque composition.

Summary of Results

Both aortic VI and coronary plaque burden were higher in psoriasis patients with comorbid depression or anxiety compared to those without (table 1). After adjustment for Framingham Risk Score, body mass index, and statin use; VI (β=0.24, p=0.02), total plaque burden (β=0.13, p=0.04), and non-calcified burden (β=0.13, p=0.04) were associated with comorbid depression and/or anxiety.

Conclusions

Patients with psoriasis who have comorbid depression or anxiety have increased aortic VI and coronary plaque burden, suggesting that identification of psychiatric diagnoses in psoriasis may be warranted for future CV risk reduction in this high risk population.

Abstract MP11 Figure 1

21: DETERMINANTS OF VASCULAR INFLAMMATION BY 18-FLUORODEOXYGLUCOSE PET/MRI: FINDINGS FROM THE PSORIASIS, ATHEROSCLEROSIS AND CARDIOMETABOLIC DISEASE INITIATIVE

Purpose of Study

Psoriasis (PSO), a chronic inflammatory disease associated with increased CV risk, provides a clinical human model to study inflammatory atherogenesis. We aimed to assess the major determinants of vascular inflammation (VI) measured by 18FDG PET-MRI in a well-phenotyped PSO cohort.

Methods Used

124 consecutive patients with PSO underwent 18FDG PET-MRI scans. We used target-to-background ratio to quantify VI 120 minutes post FDG injection. Homeostatic model assessment of insulin resistance (HOMA-IR) was measured, along with cholesterol efflux capacity (CEC) and HDL particle concentration by NMR (Liposcience) fasting.

Summary of Results

Our cohort was middle aged (mean 49±13.3 years) with mild to moderate PSO, and low CV risk (median Framingham Risk Score (FRS) 2, IQR 2–6). PSO was associated with increased VI (β=0.27, p<0.005), compared to healthy controls. VI was associated with HOMA-IR (β=0.26, p<0.001), CEC (β=−0.12, p=0.04) and HDL particle concentration (β=−0.19, p=0.003) beyond traditional CV risk factors (age, gender, FRS and BMI). Among these, HOMA-IR provided maximum incremental value in predicting VI beyond traditional risk factors (χ2=39.36, p<0.001).

Conclusions

VI by FDG PET MRI is associated with traditional CV risk factors and cardiometabolic parameters. Insulin resistance and CEC were most strongly associated with VI by 18FDG PET-MRI beyond traditional CV risk factors and BMI in PSO suggesting that cardiometabolic disease increases CV risk in PSO.

Abstract 21 Figure 1

23: VASCULAR INFLAMMATION AND AORTIC WALL CHARACTERISTICS MODULATE FOLLOWING LIFESTYLE CHANGES IN PSORIASIS PATIENTS AT 1 YEAR FOLLOW UP

Purpose of Study

Psoriasis (PSO), a chronic inflammatory skin disease, is associated with increased CV risk and vascular inflammation (VI). However, the effect of therapeutic lifestyle changes (TLC) including exercise on VI over time is unknown. We hypothesized that TLC would lead to an improvement in VI at 1 year accompanied by improvements in aortic wall characteristics.

Methods Used

65 PSO patients, recruited consecutively, underwent FDG PET/CT, phase contrast MRI scans and clinical visits for evaluation of VI, wall characteristics and exercise frequency, at baseline and 1 year follow-up. VI was measured as Target-to-background ratio (TBR), and aortic distensibility (AD) and wall thickness were assessed by commercial software on phase contrast MRI scans. Clinical parameters were ascertained by both survey and provider.

Summary of Results

VI decreased at 1 year (6.5% decrease in TBR; p<0.0001), and was inversely associated with exercise frequency beyond adjustment for CV risk factors (β=−0.27; p=0.001). Furthermore, this decrease in VI was associated with improvement in AD (40% increase; p<0.001) and aortic wall thickness (8.5% decrease; p<0.001).

Conclusions

Our findings suggest that VI improves with TLC. This 6.5% decrease in VI could lead to ∼30% reduction in future adverse events, based on a recent large prospective study. This VI reduction is also associated with improved aortic wall characteristics suggesting that targeting VI as a surrogate marker holds promise to understand the effects of TLC on CV disease.

Abstract 23 Figure 1

18: IMPROVEMENT IN PSORIASIS SKIN DISEASE SEVERITY IS ASSOCIATED WITH REDUCTION OF CORONARY PLAQUE BURDEN

Purpose of Study

Psoriasis (PSO), a chronic inflammatory disease associated with increased cardiovascular (CV) risk, provides a clinical human model to study inflammatory atherogenesis. While PSO severity is associated with both in vivo vascular disease and future CV risk, the longitudinal impact of PSO severity on coronary disease progression is unknown. We hypothesized that an improvement in PSO severity may lead to a reduction in coronary plaque burden by coronary CT angiography (CCTA).

Methods Used

Consecutively recruited PSO patients (N=50) underwent CCTA (320 detector row, Toshiba) and cardiometabolic profiling at baseline and 1-year follow-up. Total (TB) and non-calcified (NCB) coronary plaque burden were quantified using QAngio (Medis, Netherlands). PSO severity was measured as the psoriasis area severity index (PASI). The longitudinal change in coronary plaque burden was analyzed with unadjusted and adjusted regression.

Summary of Results

The cohort had a low Framingham Risk Score and mild to moderate PSO. Patients whose PSO severity improved (ΔPASI −27%; p<0.001) (N=33) had significant improvement in TB (β=0.40, p=0.003) and NCB (β=0.49, p<0.001) (table 1), beyond adjustment for traditional CV risk factors, BMI, statin use, & systemic/biologic PSO therapy.

Conclusions

Improvement in PSO severity was associated with improvement in coronary plaque burden by CCTA. Our study suggests that a reduction in skin inflammation may reduce the progression of early, non-calcified coronary plaque. Larger studies are needed to confirm these findings.

Abstract 18 Figure 1

*P-value is calculated by comparing baseline and 1-year follow-up values for variables using paired t-test for continuous variables, and Pearson's chi-squared test for categorical variables. All values are expressed as Mean±SD, unless specified otherwise. PASI: Psoriasis Area Severity Index.

Robust differences in antisaccade performance exist between COGS schizophrenia cases and controls regardless of recruitment strategies

The impaired ability to make correct antisaccades (i.e., antisaccade performance) is well documented among schizophrenia subjects, and researchers have successfully demonstrated that antisaccade performance is a valid schizophrenia endophenotype that is useful for genetic studies. However, it is unclear how the ascertainment biases that unavoidably result from recruitment differences in schizophrenia subjects identified in family versus case-control studies may influence patient-control differences in antisaccade performance. To assess the impact of ascertainment bias, researchers from the Consortium on the Genetics of Schizophrenia (COGS) compared antisaccade performance and antisaccade metrics (latency and gain) in schizophrenia and control subjects from COGS-1, a family-based schizophrenia study, to schizophrenia and control subjects from COGS-2, a corresponding case-control study. COGS-2 schizophrenia subjects were substantially older; had lower education status, worse psychosocial function, and more severe symptoms; and were three times more likely to be a member of a multiplex family than COGS-1 schizophrenia subjects. Despite these variations, which were likely the result of ascertainment differences (as described in the introduction to this special issue), the effect sizes of the control-schizophrenia differences in antisaccade performance were similar in both studies (Cohen's d effect size of 1.06 and 1.01 in COGS-1 and COGS-2, respectively). This suggests that, in addition to the robust, state-independent schizophrenia-related deficits described in endophenotype studies, group differences in antisaccade performance do not vary based on subject ascertainment and recruitment factors.

Is there an association between advanced paternal age and endophenotype deficit levels in schizophrenia?

The children of older fathers have increased risks of developing schizophrenia spectrum disorders, and among those who develop these disorders, those with older fathers present with more severe clinical symptoms. However, the influence of advanced paternal age on other important domains related to schizophrenia, such as quantitative endophenotype deficit levels, remains unknown. This study investigated the associations between paternal age and level of endophenotypic impairment in a well-characterized family-based sample from the Consortium on the Genetics of Schizophrenia (COGS). All families included at least one affected subject and one unaffected sibling. Subjects met criteria for schizophrenia (probands; n = 293) or were unaffected first-degree siblings of those probands (n = 382). Paternal age at the time of subjects’ birth was documented. Subjects completed a comprehensive clinical assessment and a battery of tests that measured 16 endophenotypes. After controlling for covariates, potential paternal age–endophenotype associations were analyzed using one model that included probands alone and a second model that included both probands and unaffected siblings. Endophenotype deficits in the Identical Pairs version of the 4-digit Continuous Performance Test and in the Penn Computerized Neurocognitive Battery verbal memory test showed significant associations with paternal age. However, after correcting for multiple comparisons, no endophenotype was significantly associated with paternal age. These findings suggest that factors other than advanced paternal age at birth may account for endophenotypic deficit levels in schizophrenia.

Characterization of Thin PtSI/p-Si Schottky Diodes

A series of PtSi on p-type Si diodes have been characterized in order to establish correlations among processing parameters, metallurgical features and electrical properties. Characterization techniques include analytical (TED, TEM), electrical (current-voltage characteristics), and optical (photoemission and absorption). The fabrication techniques involve e-beam evaporation of platinum layers at UHV levels onto VLSI grade (100) p-type silicon substrates. The silicide layers are formed via sub-eutectic solid state diffusion at 350°C. The main trends with thickness as well as possible interrelationships are described. An unexpected result is the presence of unreacted polycrystalline Pt and Pt2Si at the interface.

Combined effect of hemipteran control and liquid bait on Argentine ant populations

The invasive Argentine ant, Linepithema humile (Mayr), has become a worldwide problem capable of inflicting significant ecological and economic injury on urban, agricultural, and natural environments. The mobility of this pest ant has long been noted, rapidly moving nests to new food resources and then away as resources are depleted. This ant, like many pest ant species, has a special affinity for honeydew excreted by phloem-feeding Hemiptera. We investigated the effect of various hemipteran control strategies on terrapin scale densities and measured their indirect effect on local Argentine ant densities and foraging effort. We then determined whether this indirect treatment strategy improved the performance of an ant bait. We predicted that Argentine ants would move nests away from trees treated for Hemiptera and then move nests back when a liquid bait was offered, followed by a decline in ant numbers due to intake of the toxicant. A horticultural oil spray and soil application of the systemic insecticide, imidacloprid, had no effect on terrapin scale numbers. However, trunk-injected dicrotophos caused a reduction in scale and a decline in local Argentine ant nest density and canopy foraging effort. We also recorded a reduction in local Argentine ant ground foraging when large amounts of liquid bait were applied, and we found no evidence that combining dicrotophos with liquid ant bait performed better than each treatment alone. We suggest that a strategy of combined hemipteran control plus application of liquid ant bait can reduce local Argentine ant densities, when both components of this system are highly efficacious.

Northward expansion of the invasive Linepithema humile (Hymenoptera: Formicidae) in the eastern United States is constrained by winter soil temperatures

The invasive Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae) has been evident in the North Carolina Piedmont, United States for 90 yr but has failed to spread further north. We investigated the mechanisms preventing this expansion. The Argentine ant ceases foraging at temperatures below 5°C and we hypothesized that winter soil temperatures at higher latitudes restricted foraging long enough to cause colony starvation. We tested if the Argentine ant could successfully feed at temperatures below 5°C and found that colonies would starve. We subjected Argentine ant nests to a range of sub- and above-freezing temperatures and measured worker mortality at various time intervals. We found that Argentine ant colonies will collapse after 8.5 d at 5°C. Argentine ants can escape ambient cold temperatures by moving nests into the soil column. We tested how deeply into the soil Argentine ant queens and workers need to move to survive winter in North Carolina. Soil temperatures in the North Carolina Piedmont do not fall below 5°C for longer than nine consecutive days; therefore, Argentine ant colonies need only to retreat a few centimeters into the soil column to escape unsuitable temperatures. Winter soil temperature data from four climate stations situated from latitudes 35°, the current Eastern United States latitudinal limit for Argentine ant population expansion, to 39° were searched for periods where soil temperatures would have led to colony extirpation. North of their current distributions, extended periods of soil temperatures below 5°C regularly occur, preventing Argentine ant colonies from persisting.

Mutation analysis of the C1QTNF3 gene in patients with schizophrenia

We previously identified a small region on chromosome 5p13 related to schizophrenia in a Puerto Rican pedigree. We screened one of the positional candidate genes, C1QTNF3, for mutations in affected family members. The direct sequencing identified 10 sequence variants, including five shared by all affected family members. Genotyping of the shared variants in a Puerto Rican sample of 118 cases and 136 controls did not reveal either allelic or genotype association with schizophrenia.

Effect of an invasive and native ant on a field population of the black citrus aphid (Hemiptera: Aphididae)

Invasive ants often enter into facultative mutualisms that frequently lead to outbreaks of the hemipteran partner. Native ants may also enter into similar mutualisms but often these do not lead to outbreaks. However, field studies comparing the impact of an invasive and native ant on a honeydew-producing hemipteran are lacking. We monitored numerical changes of the black citrus aphid, Toxoptera aurantii, tended by adjacent colonies of the invasive Argentine ant, Linepithema humile, and the endemic odorous house ant, Tapinoma sessile, during 2005, 2006, and 2007. Ant-tended aphid numbers were higher than those of untended aphids, with L. humile-tended and T. sessile-tended T. aurantii populations being comparable in 2005 and 2007. However, in 2006, a severe storm, with heavy rainfall, reduced T. sessile and aphid populations in areas occupied by T. sessile, whereas L. humile and aphids tended by L. humile were not reduced. This suggested that T. sessile foraging activity and hemipteran-tending was negatively impacted by severe weather. A laboratory experiment simulating rainfall striking the surface of a leaf showed that T. sessile foraging activity declined sharply under severe simulated rainfall conditions, whereas foraging activity of L. humile did not. Maintaining populations of honeydew-producing Hemiptera across broad climatic conditions may be one mechanism by which L. humile gains a competitive advantage over native ants occupying overlapping niches.