Complementation testing identifies genes mediating effects at quantitative trait loci underlying fear-related behavior.

Knowing the genes involved in quantitative traits provides an entry point to understanding the biological bases of behavior, but there are very few examples where the pathway from genetic locus to behavioral change is known. To explore the role of specific genes in fear behavior, we mapped three fear-related traits, tested fourteen genes at six quantitative trait loci (QTLs) by quantitative complementation, and identified six genes. Four genes, Lamp, Ptprd, Nptx2, and Sh3gl, have known roles in synapse function; the fifth, Psip1, was not previously implicated in behavior; and the sixth is a long non-coding RNA, 4933413L06Rik, of unknown function. Variation in transcriptome and epigenetic modalities occurred preferentially in excitatory neurons, suggesting that genetic variation is more permissible in excitatory than inhibitory neuronal circuits. Our results relieve a bottleneck in using genetic mapping of QTLs to uncover biology underlying behavior and prompt a reconsideration of expected relationships between genetic and functional variation.

iPad-Based Neurocognitive Testing (ImPACT-QT) in Acute Adult Mild Traumatic Brain Injury/Concussion: Study on Practicality and Bedside Cognitive Scores in a Level-1 Trauma Center.

BACKGROUND: There lacks rapid standardized bedside testing to screen cognitive deficits following mild traumatic brain injury (mTBI). Immediate Post-Concussion Assessment & Cognitive Testing-Quick Test (ImPACT-QT) is an abbreviated-iPad form of computerized cognitive testing. The aim of this study is to test ImPACT-QT utility in inpatient settings. We hypothesize ImPACT-QT is feasible in the acute trauma setting. METHOD: Trauma patients ages 12-70 were administered ImPACT-QT (09/2022-09/2023). Encephalopathic/medically unstable patients were excluded. Mild traumatic brain injury was defined as documented-head trauma with loss-of-consciousness <30 minutes and arrival Glasgow Coma Scale 13-15. Patients answered Likert-scale surveys. Bivariate analyses compared demographics, attention, motor speed, and memory scores between mTBI and non-TBI controls. Multivariable logistic regression assessed memory score as a predictor of mTBI diagnosis. RESULTS: Of 233 patients evaluated (36 years [IQR 23-50], 71% [166/233] female), 179 (76%) were mTBI patients. For all patients, mean test-time was 9.3 ± 2 minutes with 93% (73/76) finding the test "easy to understand." Mild traumatic brain injury patients than non-TBI control had lower memory scores (25 [IQR 7-100] vs 43 [26-100], P = .001) while attention (5 [1-23] vs 11 [1-32]) and motor score (14 [3-28] vs 13 [4-32]) showed no significant differences. Multivariable-regression (adjustment: age, sex, race, education level, ISS, and time to test) demonstrated memory score predicted mTBI positive status (OR .96, CI .94-.98, P = .004). DISCUSSION: Immediate Post-Concussion Assessment & Cognitive Testing-Quick Test is feasible in trauma patients. Preliminary findings suggest acute mTBIs have lower memory but not attention/motor scores vs non-TBI trauma controls.

Friedman's Gradient-Boosting Algorithm Predicts Lactate-Pyruvate Ratio Trends in Cases of Intracerebral Hemorrhages.

OBJECTIVE: The local effects of an intracerebral hemorrhage (ICH) on surrounding brain tissue can be detected bedside using multimodal brain monitoring techniques. The aim of this study is to design a gradient boosting regression model using the R package boostmtree with the ability to predict lactate-pyruvate ratio measurements in ICH. METHODS: We performed a retrospective analysis of 6 spontaneous ICH and 6 traumatic ICH patients who underwent surgical removal of the clot with microdialysis catheters placed in the perihematomal zone. Predictors of glucose, lactate, pyruvate, age, sex, diagnosis, and operation status were used to design our model. RESULTS: In a holdout analysis, the model forecasted lactate-pyruvate ratio trends in a representative in-sample testing set. We anticipate that boostmtree could be applied to designs of similar regression models to analyze trends in other multimodal monitoring features across other types of acute brain injury. CONCLUSIONS: The model successfully predicted hourly lactate-pyruvate ratios in spontaneous ICH and traumatic ICH cases after the hemorrhage evacuation and displayed significantly better performance than linear models. Our results suggest that boostmtree may be a powerful tool in developing more advanced mathematical models to assess other multimodal monitoring parameters for cases in which the perihematomal environment is monitored.

Complementation testing identifies causal genes at quantitative trait loci underlying fear related behavior.

Knowing the genes involved in quantitative traits provides a critical entry point to understanding the biological bases of behavior, but there are very few examples where the pathway from genetic locus to behavioral change is known. Here we address a key step towards that goal by deploying a test that directly queries whether a gene mediates the effect of a quantitative trait locus (QTL). To explore the role of specific genes in fear behavior, we mapped three fear-related traits, tested fourteen genes at six QTLs, and identified six genes. Four genes, Lsamp, Ptprd, Nptx2 and Sh3gl, have known roles in synapse function; the fifth gene, Psip1, is a transcriptional co-activator not previously implicated in behavior; the sixth is a long non-coding RNA 4933413L06Rik with no known function. Single nucleus transcriptomic and epigenetic analyses implicated excitatory neurons as likely mediating the genetic effects. Surprisingly, variation in transcriptome and epigenetic modalities between inbred strains occurred preferentially in excitatory neurons, suggesting that genetic variation is more permissible in excitatory than inhibitory neuronal circuits. Our results open a bottleneck in using genetic mapping of QTLs to find novel biology underlying behavior and prompt a reconsideration of expected relationships between genetic and functional variation.

Cerebral microdialysis demonstrates improvements in brain metabolism with cerebrospinal fluid diversion in spontaneous intracerebral hemorrhage.

Background: Cerebral microdialysis (CMD) is an FDA-approved multimodal invasive monitoring technique that provides local brain metabolism measurements through continuous interstitial brain fluid sampling at the bedside. The past applications in traumatic brain injury and subarachnoid hemorrhage show that acute brain injury (ABI) can lead to a metabolic crisis reflected by changes in cerebral glucose, pyruvate, and lactate. However, limited literature exists on CMD in spontaneous intracerebral hemorrhage (ICH). Case Description: A 45-year-old woman presented with a Glasgow Coma Scale of 8T and left frontal ICH with a 6 mm midline shift. She underwent craniotomy and ICH evacuation. Intraoperatively, CMD, brain tissue oxygenation (PbtO2), intracranial pressure (ICP), and cerebral blood flow (CBF) catheters were placed, targeted toward the peri-hematoma region. Postoperatively, ICP was normal; however, PbtO2, CBF, glucose, and lactate/ pyruvate ratio were abnormal. Due to concern for the metabolic crisis, poor examination, and hydrocephalus on computed tomography of the head (CTH), she underwent external ventricular drainage (EVD). Post-EVD, all parameters normalized (P < 0.05 on Student's t-test). Monitors were removed, and she was discharged to a nursing facility with a modified Rankin scale of 4. Conclusion: Here, we demonstrate the safe implementation of CMD in ICH and the use of CMD in tandem with PbtO2/ICP/CBF to guide treatment in ICH. Despite a normal ICP, numerous cerebral metabolic derangements existed and improved after cerebrospinal fluid diversion. A normal ICP may not reflect underlying metabolic-substrate demands of the brain during ABI. CMD and PbtO2/CBF monitoring augment traditional ICP monitoring in brain injury. Further prospective studies will be needed to understand further the interplay between ICP, PbtO2, CBF, and CMD values in ABI.

Single-cell methylation analysis of brain tissue prioritizes mutations that alter transcription.

Relating genetic variants to behavior remains a fundamental challenge. To assess the utility of DNA methylation marks in discovering causative variants, we examined their relationship to genetic variation by generating single-nucleus methylomes from the hippocampus of eight inbred mouse strains. At CpG sequence densities under 40 CpG/Kb, cells compensate for loss of methylated sites by methylating additional sites to maintain methylation levels. At higher CpG sequence densities, the exact location of a methylated site becomes more important, suggesting that variants affecting methylation will have a greater effect when occurring in higher CpG densities than in lower. We found this to be true for a variant's effect on transcript abundance, indicating that candidate variants can be prioritized based on CpG sequence density. Our findings imply that DNA methylation influences the likelihood that mutations occur at specific sites in the genome, supporting the view that the distribution of mutations is not random.

Long-term risk of cardiovascular disease after traumatic brain injury: screening and prevention.

Traumatic brain injury (TBI) is highly prevalent among individuals participating in contact sports, military personnel, and in the general population. Although it is well known that brain injury can cause neurological and psychiatric complications, evidence from studies on individuals exposed to a single or repetitive brain injuries suggests an understudied association between TBI and the risk of developing chronic cardiovascular diseases and risk factors for cardiovascular disease. Several studies have shown that people without pre-existing comorbidities who sustain a TBI have a significantly higher risk of developing chronic cardiovascular disease, than people without TBI. Similar observations made in military and professional American-style football cohorts suggest causal pathways through which modifiable cardiovascular risk factors might mediate the relationship between brain injury and chronic neurological diseases. A better understanding of cardiovascular disease risk after TBI combined with a proactive, targeted screening programme might mitigate long-term morbidity and mortality in individuals with TBI, and improve their quality of life.

Association of Epileptiform Activity With Outcomes in Toxic-Metabolic Encephalopathy.

The clinical significance of epileptiform abnormalities (EAs) specific to toxic-metabolic encephalopathy (TME) is unknown. OBJECTIVES: To quantify EA burden in patients with TME and its association with neurologic outcomes. DESIGN SETTING AND PARTICIPANT: This is a retrospective study. A cohort of patients with TME and EA (positive) were age, Sequential Organ Failure Assessment Score, Acute Physiology and Chronic Health Evaluation II (APACHE-II) score matched to a cohort of TME patients without EA (control). Univariate analysis compared EA-positive patients against controls. Multivariable logistical regression adjusting for underlying disease etiology was performed to examine the relationship between EA burden and probability of poor neurologic outcome (modified Rankin Score [mRS] 4-6) at discharge. Consecutive admissions to inpatient floors or ICUs that underwent continuous electroencephalography (cEEG) monitoring at a single center between 2012 and 2019. Inclusion criteria were 1) patients with TME diagnosis, 2) age greater than 18 years, and 3) greater than or equal to 16 hours of cEEG. Patients with acute brain injury and cardiac arrest were excluded. MAIN OUTCOMES AND MEASURES: Poor neurologic outcome defined by mRS (mRS 4-6). RESULTS: One hundred sixteen patients were included, 58 with EA and 58 controls without EA, where matching was performed on age and APACHE-II score. The median age was 66 (Q1-Q3, 57-75) and median APACHE II score was 18 (Q1-Q3, 13-22). Overall cohort discharge mortality was 22% and 70% had a poor neurologic outcome. Peak EA burden was defined as the 12-hour window of recording with the highest prevalence of EAs. In multivariable analysis adjusted for Charlson Comorbidity Index and primary diagnosis, presence of EAs was associated with poor outcome (odds ratio 3.89; CI [1.05-14.2], p = 0.041). Increase in peak EA burden from 0% to 100% increased probability of poor discharge neurologic outcome by 30%. CONCLUSIONS AND RELEVANCE: Increasing burden of EA is associated with worse discharge outcomes in patients with TME. Future studies are needed to determine whether short-term treatment with anti-seizure medications while medically treating the underlying metabolic derangement improves outcomes.

Development of a panel of U.S. adult tobacco users to inform tobacco regulatory science.

The National Panel of Tobacco Consumer Studies (TCS Panel) is a probability-based panel of about 4,000 U.S. adult cigarette, cigar, and smokeless tobacco users developed by the U.S. Food and Drug Administration's Center for Tobacco Products to conduct observational and experimental studies to inform tobacco regulatory activities. This paper describes the methods and characteristics of the current panel. The TCS Panel employed a stratified 4-stage sample design and in-person screening of U.S. sampled households. Selected eligible adults participated in an enrollment interview and completed a baseline survey assessing tobacco use behaviors to enroll in the Panel; 3,893 individuals were enrolled from September 2016-August 2017. Replenishment occurred from July 2019-December 2019 with 2,260 new members, for a current panel of 3,929 members. Demographic and tobacco use characteristics of the current panel were analyzed in 2020. Most demographic characteristics of the TCS Panel are similar to those of U.S. tobacco users in the 2018 National Health Interview Survey, suggesting a lack of systematic bias in the Panel. Small, but statistically significant, differences were observed in the proportion of 18- to 25-year-olds; high school diploma and bachelor's degree/higher; never married and married (p < 0.05 for all). The TCS Panel appears to be representative of U.S. cigarette, cigar, and smokeless tobacco users; such panels can be a feasible method for conducting tobacco regulatory science research. The TCS Panel has been used to field studies examining purchasing behaviors, receipt and use of free samples/coupons, and the impact of a hypothetical tobacco product standard.

Association of Traumatic Brain Injury With the Risk of Developing Chronic Cardiovascular, Endocrine, Neurological, and Psychiatric Disorders.

Importance: Increased risk of neurological and psychiatric conditions after traumatic brain injury (TBI) is well-defined. However, cardiovascular and endocrine comorbidity risk after TBI in individuals without these comorbidities and associations with post-TBI mortality have received little attention. Objective: To assess the incidence of cardiovascular, endocrine, neurological, and psychiatric comorbidities in patients with mild TBI (mTBI) or moderate to severe TBI (msTBI) and analyze associations between post-TBI comorbidities and mortality. Design, Setting, and Participants: This prospective longitudinal cohort study used hospital-based patient registry data from a tertiary academic medical center to select patients without any prior clinical comorbidities who experienced TBI from 2000 to 2015. Using the same data registry, individuals without head injuries, the unexposed group, and without target comorbidities were selected and age-, sex-, and race-frequency-matched to TBI subgroups. Patients were followed-up for up to 10 years. Data were analyzed in 2021. Exposures: Mild or moderate to severe head trauma. Main Outcomes and Measures: Cardiovascular, endocrine, neurologic, and psychiatric conditions were defined based on International Classification of Diseases, Ninth Revision (ICD-9) or International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10). Associations between TBI and comorbidities, as well as associations between the comorbidities and mortality, were analyzed. Results: A total of 4351 patients with mTBI (median [IQR] age, 45 [29-57] years), 4351 patients with msTBI (median [IQR] age, 47 [30-58] years), and 4351 unexposed individuals (median [IQR] age, 46 [30-58] years) were included in analyses. In each group, 45% of participants were women. mTBI and msTBI were significantly associated with higher risks of cardiovascular, endocrine, neurologic, and psychiatric disorders compared with unexposed individuals. In particular, hypertension risk was increased in both mTBI (HR, 2.5; 95% CI, 2.1-2.9) and msTBI (HR, 2.4; 95% CI, 2.0-2.9) groups. Diabetes risk was increased in both mTBI (HR, 1.9; 95% CI, 1.4-2.7) and msTBI (HR, 1.9; 95% CI, 1.4-2.6) groups, and risk of ischemic stroke or transient ischemic attack was also increased in mTBI (HR, 2.2; 95% CI, 1.4-3.3) and msTBI (HR, 3.6; 95% CI, 2.4-5.3) groups. All comorbidities in the TBI subgroups emerged within a median (IQR) of 3.49 (1.76-5.96) years after injury. Risks for post-TBI comorbidities were also higher in patients aged 18 to 40 years compared with age-matched unexposed individuals: hypertension risk was increased in the mTBI (HR, 5.9; 95% CI, 3.9-9.1) and msTBI (HR, 3.9; 95% CI, 2.5-6.1) groups, while hyperlipidemia (HR, 2.3; 95% CI, 1.5-3.4) and diabetes (HR, 4.6; 95% CI, 2.1-9.9) were increased in the mTBI group. Individuals with msTBI, compared with unexposed patients, had higher risk of mortality (432 deaths [9.9%] vs 250 deaths [5.7%]; P < .001); postinjury hypertension (HR, 1.3; 95% CI, 1.1-1.7), coronary artery disease (HR, 2.2; 95% CI, 1.6-3.0), and adrenal insufficiency (HR, 6.2; 95% CI, 2.8-13.0) were also associated with higher mortality. Conclusions and Relevance: These findings suggest that TBI of any severity was associated with a higher risk of chronic cardiovascular, endocrine, and neurological comorbidities in patients without baseline diagnoses. Medical comorbidities were observed in relatively young patients with TBI. Comorbidities occurring after TBI were associated with higher mortality. These findings suggest the need for a targeted screening program for multisystem diseases after TBI, particularly chronic cardiometabolic diseases.

Venous Thromboembolism Risk and Outcomes Following Decompressive Craniectomy in Severe Traumatic Brain Injury: An Analysis of the Nationwide Inpatient Sample Database.

OBJECTIVE: Traumatic brain injury (TBI) is a risk factor for venous thromboembolism (VTE). The risk of VTE after decompressive craniectomy (DC) and its effects on the outcomes are unknown. We assessed the incidence of VTE, associated risk factors, and effects on the outcomes. METHODS: Using the National Inpatient Sample database, the hospitalizations of patients aged ≥18 years with a severe TBI diagnosis from 2004 to 2014 were extracted. The outcome was discharge status without mortality. Multivariable logistic and linear regressions were used. RESULTS: Of the 349,165 TBI hospitalizations, 23,813 (6.82%) had undergone DC and 14,175 (4.06%) had developed VTE. The VTE incidence was higher after DC compared with no DC (6.14% vs. 3.91%; P < 0.0001). DC (odds ratio [OR], 1.29; P < 0.005) was an independent predictor for the development of VTE. Age (OR, 1.26; P < 0.005), chronic lung disease (OR, 1.58; P < 0.05), electrolyte imbalance (OR, 1.43; P < 0.05), liver disease (OR, 0.10; P < 0.05), urinary tract infection (OR, 1.56; P < 0.05), pneumonia (OR, 2.03; P < 0.0001), and sepsis (OR, 1.57; P < 0.05) were significantly associated with the development of VTE. Obesity (OR, 2.09; P > 0.05) and spine injury (OR, 2.03; P > 0.05) showed a trend toward significance. VTE was associated with worse discharge outcomes (OR, 1.40; P < 0.05), longer lengths of stay (OR, 1.01; P < 0.00001), and higher costs (P < 0.0001). CONCLUSIONS: Our study showed an independent association between DC and an increased risk of VTE for patients with severe TBI. The development of VTE after DC increased the proportion of poor outcomes, prolonged the length of stay, and increased the hospitalization costs. Older patients with obesity, an electrolyte imbalance, chronic lung disease, spine injury, and infections were at a greater risk of VTE after DC. These risk factors could help in considering VTE prophylaxis for these patients.

The impact and restoration of colorectal services during the coronavirus disease 2019 pandemic: A view from Oxford.

Aim: The coronavirus pandemic has significantly disrupted the way we deliver healthcare worldwide. We have been flexible and creative in order to continue providing elective colorectal cancer operations and to restart services for benign cases during the recovery period of the pandemic. In this paper, we describe the impact of coronavirus on our elective services and how we have implemented new patient pathways to allow us to continue providing patient care. Patients and Methods: Data on major colorectal elective resections were prospectively collected in an Enhanced Recovery After Surgery (ERAS) database. Data on the number of proctology cases and telemed appointments were collected from the hospital theatre information management system and electronic patient record system, respectively. Results: During the pandemic, there was a complete shift towards cancer cases, with benign services and proctology cases being placed on hold. Hospital length of stay was reduced. We implemented earlier hospital discharge and more intense telephone follow-up after elective major surgery. This has not resulted in an increase in postoperative complications, nor any increase in readmission to hospital. During the recovery phase, we have introduced a higher proportion of telemed consultations, including one-stop telemed proctology clinics, resulting in straight to tests or investigations. Conclusion: We have created a streamlined multidisciplinary pathway to reinstate our elective colorectal services as soon as possible and to minimise potential harm caused to patients whose treatment have been delayed. We anticipate many of these changes will be permanently incorporated into our clinical practice once the pandemic is over.

Simulation-Based Training Improves Fellows' Competence in Brain Death Discussion and Declaration.

BACKGROUND: Despite well-defined American Academy of Neurology guidelines for death by whole brain criteria (brain death), there is marked variability in national practice, which some have attributed to lack of formal education. Further, communication with surrogates and families about brain death is integral to brain death declaration. As such, we developed a targeted brain death curriculum combining didactics and simulation-based education to improve examination and subsequent communication skills with families. METHODS: Multidisciplinary critical care fellows participated in (1) didactic and case-based curriculum, (2) brain death simulated examination (SimMan3G mannequin), and (3) a standardized family scenario with delivery of a brain death diagnosis to a surrogate "family member". Fellows completed a precurriculum and postcurriculum multiple choice knowledge test and survey (Likert 1 to 10 scale) evaluating measures regarding diagnosis and communication of brain death. t Test and 2-tailed Wilcoxon signed rank test were used for statistical analysis (P<0.05). RESULTS: Thirteen critical care fellows participated in the curriculum. Most fellows [80% (N=12)] had only participated in 0 to 5 brain death declarations before this intervention. There was significant improvement across all measures: self-rated knowledge (P=0.004), perceived knowledge relative to peers (P=0.002), confidence (P=0.001), and comfort (P=0.001) with performing a brain death exam, and comfort with family discussion (P=0.01). Objective test scores improved from 56 to 73% after simulation (P=0.004). All fellows found the curriculum beneficial. CONCLUSION: Trainees may lack sufficient exposure to brain death education. Didactics with simulation-based education can improve objective knowledge and subjective measures of comfort with brain death declaration and surrogate communication.

Cerebral Hyperperfusion and Delayed Coma Recovery after Subdural Hematoma Evacuation.

Acute subdural hematoma is a devastating neurological injury with significant morbidity and mortality. In patients with large subdural hematoma resulting in compression of the underlying brain and lateral brain shift, severe neurological deficits and coma can occur. Emergent neurosurgical decompression is a life-saving intervention which improves mortality and neurological function. Persistent coma despite subdural hematoma evacuation is often the result of persistent midline shift, cerebral infarctions related to initial elevated intracranial pressure and herniation, nonconvulsive seizures, and other metabolic and infectious causes; however, a subset of patients remains comatose without a discernable etiology. In this report, we describe an elderly patient who remained comatose without a known cause for several weeks after subdural hematoma evacuation and was found to have delayed cerebral hyperperfusion on brain imaging. After several days, there was marked recovery of consciousness which occurred in a timeframe that matched improvement in brain imaging findings. Cerebral hyperperfusion following subdural hematoma evacuation requires further investigation, and should be considered as a cause of persistent but potentially recoverable coma.

An overview of mental health during the COVID-19 pandemic.

Since its initial outbreak in late 2019, the COVID-19 pandemic has profoundly affected the global community. In addition to the negative health consequences of contracting COVID-19, the implementation of strict quarantine and lockdown measures has also disrupted social networks and devastated the global economy. As a result, there is rising concern that the pandemic has taken a toll on the mental health of the general population. To better understand its impact, an increasing number of studies examined the effects of the pandemic on mental health and psychosocial implications of enforced quarantine and lockdown. In this article, we aim to review and summarize the findings from a variety of studies that have explored the psychosociological effects of the pandemic and its impact on the mental well-being of the general population. We will also examine how various demographic groups, such as the elderly and youth, can be more susceptible or resilient to the pandemic's mental health effects. We hope to provide a broader understanding of the underlying causes of mental health issues triggered by the pandemic and provide recommendations that may be employed to address mental health issues in the population over the long-term.