Germline genetic regulation of the colorectal tumor immune microenvironment.

OBJECTIVE: To evaluate the contribution of germline genetics to regulating the briskness and diversity of T cell responses in CRC, we conducted a genome-wide association study to examine the associations between germline genetic variation and quantitative measures of T cell landscapes in 2,876 colorectal tumors from participants in the Molecular Epidemiology of Colorectal Cancer Study (MECC). METHODS: Germline DNA samples were genotyped and imputed using genome-wide arrays. Tumor DNA samples were extracted from paraffin blocks, and T cell receptor clonality and abundance were quantified by immunoSEQ (Adaptive Biotechnologies, Seattle, WA). Tumor infiltrating lymphocytes per high powered field (TILs/hpf) were scored by a gastrointestinal pathologist. Regression models were used to evaluate the associations between each variant and the three T-cell features, adjusting for sex, age, genotyping platform, and global ancestry. Three independent datasets were used for replication. RESULTS: We identified a SNP (rs4918567) near RBM20 associated with clonality at a genome-wide significant threshold of 5 × 10- 8, with a consistent direction of association in both discovery and replication datasets. Expression quantitative trait (eQTL) analyses and in silico functional annotation for these loci provided insights into potential functional roles, including a statistically significant eQTL between the T allele at rs4918567 and higher expression of ADRA2A (P = 0.012) in healthy colon mucosa. CONCLUSIONS: Our study suggests that germline genetic variation is associated with the quantity and diversity of adaptive immune responses in CRC. Further studies are warranted to replicate these findings in additional samples and to investigate functional genomic mechanisms.

Perioperative management of a double valve replacement and coronary artery bypass graft in a patient with carcinoid syndrome; a case report and literature review.

INTRODUCTION: Carcinoid tumors are rare neuroendocrine tumors; about 5% of patients develop the carcinoid syndrome. We present the case of a patient with carcinoid syndrome undergoing cardiac surgery. CASE REPORT: A 74-year-old patient with carcinoid heart disease and hepatic metastases underwent double valve replacement and CABG. The patient was on octreotide therapy and antihypertensive medication. An octreotide infusion was commenced perioperatively. Pharmaceutical agents that could potentially precipitate histamine release or exacerbate catecholamine secretion and carcinoid crises were avoided. Postoperatively, recovery was complicated by atrial fibrillation, chest infection, pleural effusions, acute kidney injury and delirium. DISCUSSION: Hepatic metastases cause systemic hormones' secretion, which cause a carcinoid crisis. Perioperative administration of octreotide is used, while vigilance is required to differentiate between hemodynamic effects related to the operation or disease specific factors. CONCLUSION: No carcinoid crisis was evident perioperatively. High vigilance with appropriate monitoring, aggressive management combined with meticulous choice of pharmaceutical agents led to this outcome.

Post-Operative Thoracic Epidural Analgesia and Incidence of Major Complications according to Specific Safety Standardized Documentation: A Large Retrospective Dual Center Experience.

(1) Background: Thoracic epidural analgesia is considered the gold standard in post-operative pain management following thoracic surgery. This study was designed to explore the safety of thoracic epidural analgesia and to quantify the incidence of its post-operative complications and side effects in patients undergoing thoracotomy for major surgery, such as resection of lung malignancies and lung transplantation. (2) Methods: This is a retrospective, dual-center observational study including patients that underwent major thoracic surgery including lung transplantation and received concurrent placement of thoracic epidural catheters for post-operative analgesia. An electronic system of referral and documentation of complications was used, and information was retrieved from our electronic critical care charting system. (3) Results: In total, 1145 patients were included in the study. None of the patients suffered any major complication, including hematoma, abscess, or permanent nerve damage. (4) Conclusions: the present study showed that in experienced centers, post-operative epidural analgesia in patients with thoracotomy is a safe technique, manifesting minimal, none-serious complications.

Heterozygote advantage at HLA class I and II loci and reduced risk of colorectal cancer.

Objective: Reduced diversity at Human Leukocyte Antigen (HLA) loci may adversely affect the host's ability to recognize tumor neoantigens and subsequently increase disease burden. We hypothesized that increased heterozygosity at HLA loci is associated with a reduced risk of developing colorectal cancer (CRC). Methods: We imputed HLA class I and II four-digit alleles using genotype data from a population-based study of 5,406 cases and 4,635 controls from the Molecular Epidemiology of Colorectal Cancer Study (MECC). Heterozygosity at each HLA locus and the number of heterozygous genotypes at HLA class -I (A, B, and C) and HLA class -II loci (DQB1, DRB1, and DPB1) were quantified. Logistic regression analysis was used to estimate the risk of CRC associated with HLA heterozygosity. Individuals with homozygous genotypes for all loci served as the reference category, and the analyses were adjusted for sex, age, genotyping platform, and ancestry. Further, we investigated associations between HLA diversity and tumor-associated T cell repertoire features, as measured by tumor infiltrating lymphocytes (TILs; N=2,839) and immunosequencing (N=2,357). Results: Individuals with all heterozygous genotypes at all three class I genes had a reduced odds of CRC (OR: 0.74; 95% CI: 0.56-0.97, p= 0.031). A similar association was observed for class II loci, with an OR of 0.75 (95% CI: 0.60-0.95, p= 0.016). For class-I and class-II combined, individuals with all heterozygous genotypes had significantly lower odds of developing CRC (OR: 0.66, 95% CI: 0.49-0.87, p= 0.004) than those with 0 or one heterozygous genotype. HLA class I and/or II diversity was associated with higher T cell receptor (TCR) abundance and lower TCR clonality, but results were not statistically significant. Conclusion: Our findings support a heterozygote advantage for the HLA class-I and -II loci, indicating an important role for HLA genetic variability in the etiology of CRC.

Cone beam computed tomography for dose calculation quality assurance for magnetic resonance-only radiotherapy.

BACKGROUND AND PURPOSE: Magnetic Resonance (MR)-only prostate radiotherapy using synthetic Computed Tomography (sCT) algorithms with high dose accuracy has been clinically implemented. MR images can suffer from geometric distortions so Quality Assurance (QA) using an independent, geometrically accurate, image could be required. The first-fraction Cone Beam CT (CBCT) has demonstrated potential but has not been evaluated in a clinical MR-only pathway. This study evaluated the clinical use of CBCT for dose accuracy QA of MR-only radiotherapy. MATERIALS AND METHODS: A total of 49 patients treated with MR-only prostate radiotherapy were divided into two cohorts. Cohort 1 (20 patients) received a back-up CT, whilst Cohort 2 (29 patients) did not. All patients were planned using the sCT and received daily CBCT imaging with MR-CBCT soft-tissue matching. Each CBCT was calibrated using a patient-specific stepwise Hounsfield Units-to-mass density curve. The treatment plan was recalculated on the first-fraction CBCT using the clinically applied soft-tissue match and the doses compared. For Cohort 1 the sCT was rigidly registered to the back-up CT, the plan recalculated and doses compared. RESULTS: Mean sCT-CBCT dose difference across both cohorts was - 0.6 ± 0.1 % (standard error of the mean, range - 2.3 % , 2.3 % ), with 47/49 patients within [ - 2 % , 1 % ]. The sCT-CBCT dose difference was systematically lower than the sCT-CT by - 0.7 ± 0.6 % ( ± 95 % limits of agreement). The mean sCT-CBCT gamma pass rate ( 2 % / 2 mm ) was 96.1 ± 0.4 % ( 85.4 % , 99.7 % ). CONCLUSIONS: CBCT-based dose accuracy QA for MR-only radiotherapy appears clinically feasible. There was a small systematic sCT-CBCT dose difference implying asymmetric tolerances of [ - 2 % , 1 % ] would be appropriate.

Carbohydrate Intake Prior to Oral Glucose Tolerance Testing.

With the emergence of glycated hemoglobin as a diagnostic test for diabetes, oral glucose tolerance tests (OGTTs) have become rare in endocrinology practice. As they have moved out of favor, the importance of patient instructions on preparation prior to OGTT has faded from memory. Decades-old literature, well-known to endocrinologists a generation ago, emphasized the importance of carbohydrate intake prior to OGTT. In this expert endocrine consult, we discuss an OGTT performed in a research setting without adequate carbohydrate intake at the evening meal prior to the OGTT. The resultant elevated plasma glucose levels at 1-hour and 2-hours mimicked the loss of first-phase insulin release seen in early type 1 and type 2 diabetes. With clinical concern that the research participant had evolving type 1 or type 2 diabetes, the volunteer was subjected to additional testing and experienced anxiety. Repeat OGTT was normal after adequate carbohydrate intake (>150 grams/day and >50 grams the evening prior to overnight fast for the study). The physiology of this phenomenon is explored and is likely mediated through beta cell adaptation and alteration in peripheral glucose uptake in response to nutrient exposure. The learnings of decades ago have clearly faded, and this literature should be revisited to ensure that OGTT results are not compromised when ordered for clinical or research purposes.

Experimental increase of blood glucose alters resting state EEG measures of excitation-inhibition balance.

NEW FINDINGS: What is the central question of this study? Glucose is the dominant energy source for the brain. However, little is known about how glucose metabolism impacts the coordination of network activity in the brain in healthy adults. What is the main finding and its importance? We demonstrate that both α oscillations and the aperiodic signal components of the resting EEG are modulated by experimentally elevated blood glucose concentrations. Our findings suggest that glucose increases measures associated with excitation-inhibition (E:I) balance, but that the effect on α oscillations might plateau. Understanding the relationship between glucose consumption and E:I balance is crucial to developing our understanding of how metabolism shapes human brain activity. ABSTRACT: Brain network oscillations can be divided broadly into periodic and aperiodic signal components, which are sensitive to state-dependent changes in network coordination and excitation-inhibition (E:I) balance. We sought to address whether the dominant energy source of the brain, glucose, is implicated in the regulation of network activity and excitability. We conducted an experimenter-blind, crossover study of the effect of blood glucose level (BGL) on the resting EEG frequency spectrum. Participants consumed a glucose drink (75 g glucose) or an equivalent volume of water on two separate visits. EEG data were sampled before and ≤3 h after the drink. We found that the experimentally induced changes in BGL exhibited an inverted U-shaped relationship, with changes in the individual α frequency peak, whereas the slope of the aperiodic signal component of the frequency spectrum showed a positive linear association suggestive of greater excitation. In contrast, peak α power, which is typically associated with top-down inhibitory processes, was negatively associated with changes in BGL. Collectively, these results suggest that high BGL alters brain network coordination in the form of α oscillations and measures associated with E:I balance.

Intact Auditory Cortical Cross-Frequency Coupling in Early and Chronic Schizophrenia.

BACKGROUND: Previous work has identified a hierarchical organization of neural oscillations that supports performance of complex cognitive and perceptual tasks, and can be indexed with phase-amplitude coupling (PAC) between low- and high-frequency oscillations. Our aim was to employ enhanced source localization afforded by magnetoencephalography (MEG) to expand on earlier reports of intact auditory cortical PAC in schizophrenia and to investigate how PAC may evolve over the early and chronic phases of the illness. METHODS: Individuals with early schizophrenia (n=12) (≤5 years of illness duration), chronic schizophrenia (n=16) (>5 years of illness duration) and healthy comparators (n = 17) performed the auditory steady state response (ASSR) to 40, 30, and 20 Hz stimuli during MEG recordings. We estimated amplitude and PAC on the MEG ASSR source localized to the auditory cortices. RESULTS: Gamma amplitude during 40-Hz ASSR exhibited a significant group by hemisphere interaction, with both patient groups showing reduced right hemisphere amplitude and no overall lateralization in contrast to the right hemisphere lateralization demonstrated in controls. We found significant PAC in the right auditory cortex during the 40-Hz entrainment condition relative to baseline, however, PAC did not differ significantly between groups. CONCLUSIONS: In the current study, we demonstrated an apparent sparing of ASSR-related PAC across phases of the illness, in contrast with impaired cortical gamma oscillation amplitudes. The distinction between our PAC and evoked ASSR findings supports the notion of separate but interacting circuits for the generation and maintenance of sensory gamma oscillations. The apparent sparing of PAC in both early and chronic schizophrenia patients could imply that the neuropathology of schizophrenia differentially affects these mechanisms across different stages of the disease. Future studies should investigate the distinction between PAC during passive tasks and more cognitively demanding task such as working memory so that we can begin to understand the influence of schizophrenia neuropathology on the larger framework for modulating neurocomputational capacity.

Gene Expression in Patient-Derived Neural Progenitors Implicates WNT5A Signaling in the Etiology of Schizophrenia.

BACKGROUND: Genome-wide association studies of schizophrenia have demonstrated that variations in noncoding regions are responsible for most of the common variation heritability of the disease. It is hypothesized that these risk variants alter gene expression. Therefore, studying alterations in gene expression in schizophrenia may provide a direct approach to understanding the etiology of the disease. In this study we use cultured neural progenitor cells derived from olfactory neuroepithelium (CNON cells) as a genetically unaltered cellular model to elucidate the neurodevelopmental aspects of schizophrenia. METHODS: We performed a gene expression study using RNA sequencing of CNON cells from 111 control subjects and 144 individuals with schizophrenia. Differentially expressed genes were identified with DESeq2 software, using covariates to correct for sex, age, library batches, and 1 surrogate variable component. RESULTS: A total of 80 genes were differentially expressed (false discovery rate < 10%), showing enrichment in cell migration, cell adhesion, developmental process, synapse assembly, cell proliferation, and related Gene Ontology categories. Cadherin and Wnt signaling pathways were positive in overrepresentation test, and, in addition, many genes were specifically involved in WNT5A signaling. The differentially expressed genes were modestly, but significantly, enriched in the genes overlapping single nucleotide polymorphisms with genome-wide significant association from the Psychiatric Genomics Consortium genome-wide association study of schizophrenia. We also found substantial overlap with genes associated with other psychiatric disorders or brain development, enrichment in the same Gene Ontology categories as genes with mutations de novo in schizophrenia, and studies of induced pluripotent stem cell-derived neural progenitor cells. CONCLUSIONS: CNON cells are a good model of the neurodevelopmental aspects of schizophrenia and can be used to elucidate the etiology of the disorder.

Loss-of-function mutation in inositol monophosphatase 1 (IMPA1) results in abnormal synchrony in resting-state EEG.

BACKGROUND: Dysregulation of the inositol cycle is implicated in a wide variety of human diseases, including developmental defects and neurological diseases. A homozygous frameshift mutation in IMPA1, coding for the enzyme inositol monophosphatase 1 (IMPase), has recently been associated with severe intellectual disability (ID) in a geographically isolated consanguineous family in Northeastern Brazil (Figueredo et al., 2016). However, the neurophysiologic mechanisms that mediate the IMPA1 mutation and associated ID phenotype have not been characterized. To this end, resting EEG (eyes-open and eyes-closed) was collected from the Figueredo et al. pedigree. Quantitative EEG measures, including mean power, dominant frequency and dominant frequency variability, were investigated for allelic associations using multivariate family-based association test using generalized estimating equations. RESULTS: We found that the IMPA1 mutation was associated with relative decreases in frontal theta band power as well as altered alpha-band variability with no regional specificity during the eyes-open condition. For the eyes-closed condition, there was altered dominant theta frequency variability in the central and parietal regions. CONCLUSIONS: These findings represent the first human in vivo phenotypic assessment of brain function disturbances associated with a loss-of-function IMPA1 mutation, and thus an important first step towards an understanding the pathophysiologic mechanisms of intellectual disability associated with the mutation that affects this critical metabolic pathway.

Serum anticholinergicity is associated with reduced prefrontal brain function in early course schizophrenia.

Increased anticholinergic activity resulting from pharmacotherapies used to treat schizophrenia is associated with poorer cognition. However the neural mechanisms underlying this effect are unknown. In this study of 39 early course schizophrenia outpatients, we demonstrate that increased serum anticholinergic activity is associated with reduced activation across the prefrontal cortex, including the dorsolateral, anterior, and medial prefrontal cortices, during two tasks of cognitive control. Lower activation in the dorsolateral and anterior prefrontal cortices mediated the association between increased anticholinergicity and poorer neurocognitive function. Such findings provide preliminary insight into how anticholinergic medications may impact cognition through reduced prefrontal cortical function in schizophrenia.

Assessing characteristics of RNA amplification methods for single cell RNA sequencing.

BACKGROUND: Recently, measurement of RNA at single cell resolution has yielded surprising insights. Methods for single-cell RNA sequencing (scRNA-seq) have received considerable attention, but the broad reliability of single cell methods and the factors governing their performance are still poorly known. RESULTS: Here, we conducted a large-scale control experiment to assess the transfer function of three scRNA-seq methods and factors modulating the function. All three methods detected greater than 70% of the expected number of genes and had a 50% probability of detecting genes with abundance greater than 2 to 4 molecules. Despite the small number of molecules, sequencing depth significantly affected gene detection. While biases in detection and quantification were qualitatively similar across methods, the degree of bias differed, consistent with differences in molecular protocol. Measurement reliability increased with expression level for all methods and we conservatively estimate measurements to be quantitative at an expression level greater than ~5-10 molecules. CONCLUSIONS: Based on these extensive control studies, we propose that RNA-seq of single cells has come of age, yielding quantitative biological information.

Development of sensory gamma oscillations and cross-frequency coupling from childhood to early adulthood.

Given the importance of gamma oscillations in normal and disturbed cognition, there has been growing interest in their developmental trajectory. In the current study, age-related changes in sensory cortical gamma were studied using the auditory steady-state response (ASSR), indexing cortical activity entrained to a periodic auditory stimulus. A large sample (n = 188) aged 8-22 years had electroencephalography recording of ASSR during 20-, 30-, and 40-Hz click trains, analyzed for evoked amplitude, phase-locking factor (PLF) and cross-frequency coupling (CFC) with lower frequency oscillations. Both 40-Hz evoked power and PLF increased monotonically from 8 through 16 years, and subsequently decreased toward ages 20-22 years. CFC followed a similar pattern, with strongest age-related modulation of 40-Hz amplitude by the phase of delta oscillations. In contrast, the evoked power, PLF and CFC for the 20- and 30-Hz stimulation were distinct from the 40-Hz condition, with flat or decreasing profiles from childhood to early adulthood. The inverted U-shaped developmental trajectory of gamma oscillations may be consistent with interacting maturational processes-such as increasing fast GABA inhibition that enhances gamma activity and synaptic pruning that decreases gamma activity-that may continue from childhood through to adulthood.

Impact of concomitant coronary artery bypass grafting on in-hospital outcome in octogenarians undergoing aortic valve replacement.

BACKGROUND AND AIM OF THE STUDY: Abundant data are available reporting excellent in-hospital outcomes after surgical aortic valve replacement (AVR) in octogenarians. However, there is a paucity of studies reporting the in-hospital outcome of concomitant AVR and coronary artery bypass grafting (CABG) in this group of patients. Hence, a comparison was made of the impact of concomitant AVR and CABG versus isolated AVR on in-hospital outcome in octogenarians. METHODS: Between January 2001 and October 2011, a total of 114 consecutive octogenarians undergoing combined AVR and CABG were compared with a control group of octogenarians (n = 68) undergoing isolated AVR. A retrospective analysis was performed of a prospectively collected cardiac surgery database. In addition, the medical notes and charts of all study patients were reviewed. RESULTS: The two groups had a similar mean age (AVR 82.3 +/- 2.4 years versus AVR + CABG 82.6 +/- 2.1 years; p = 0.91), demographics and EuroSCORE (AVR 11.4 versus AVR + CABG 13.2; p = 0.12). The aortic cross-clamp and cardiopulmonary bypass times were longer for AVR + CABG patients (p < 0.001). In-hospital mortality (7.4% after isolated AVR, 9.6% after AVR + CABG; p = 0.35 between groups) and major clinical outcomes for the two groups were found to be similar except for an increased need for hemofiltration in AVR + CABG patients (p = 0.02). CONCLUSION: In-hospital outcomes for concomitant AVR and CABG in octogenarians are comparable to those of isolated AVR, justifying the performance of combined AVR and CABG in this high-risk group of carefully selected patients.

In-hospital outcomes of pedicled bilateral internal mammary artery use in diabetic and nondiabetic patients undergoing off-pump coronary artery bypass grafting: single-surgeon, single-center experience.

OBJECTIVE: A common perception is that use of pedicled bilateral internal mammary arteries (BIMA) increases the risk of sternal wound complications in diabetic patients undergoing coronary artery bypass grafting (CABG). The purpose of this study was to compare the in-hospital outcomes of CABG using pedicled BIMA in diabetic and nondiabetic patients. METHODS: From September 1998 to September 2010, 390 consecutive diabetic patients and 519 nondiabetic patients underwent isolated off-pump CABG using pedicled BIMA. The 2 groups had comparable preoperative demographics except for a higher prevalence of acute myocardial infarction (18.9% versus 6.1%, P = .01), peripheral vascular disease (17.2% versus 2.7%, P = .001), an ejection fraction <30% (17.7% versus 8.5%, P = .02), and chronic renal failure (4.5% versus 0.9%, P = .01) in the diabetic patients. RESULTS: The operative mortality rate of the diabetic patients was comparable to that of the nondiabetic patients (2.8% versus 2.1%, P = .87). The in-hospital outcomes, including occurrence of superficial and deep sternal wound infections, were similar except for an increased occurrence of wound infection at the vein harvest site (6.6% versus 1.1%, P = .04) and a need for hemofiltration (11.8% versus 2.1%, P = .02) in the diabetic patients. CONCLUSIONS: Pedicled BIMA use is associated with comparable incidences of sternal wound complications and other outcomes in diabetic patients and nondiabetic patients. Strict perioperative glycemic control, adherence to meticulous closure technique, and postoperative management of surgical wounds can make pedicled BIMA use a default strategy for diabetic patients.

Concomitant off-pump coronary artery bypass grafting results in improved in-hospital outcomes for patients with ischemic mitral regurgitation undergoing surgery.

OBJECTIVE: Surgical management of ischemic mitral regurgitation (IMR) has primarily consisted of revascularization with or without the addition of mitral valve repair or replacement. We hypothesize that performing off-pump coronary artery bypass (OPCAB) grafting before fixing MR improves in-hospital outcomes for patients with IMR undergoing surgery. METHODS: From January 2000 through December 2010, a total of 96 consecutive patients with moderate or severe IMR, as determined by preoperative echocardiography, underwent on-pump coronary artery bypass grafting (CABG) (n = 66) or OPCAB (n = 30) revascularization with concomitant mitral valve repair or replacement. A retrospective analysis of a prospectively collected cardiac surgery database (PATS; Dendrite Clinical Systems, Oxford, UK) was performed. In addition, medical notes and charts were reviewed for all study patients. RESULTS: The 2 groups had similar preoperative demographic and EuroSCORE risk-stratification characteristics. The operative mortality rate for the entire cohort was 9.4%. Patients who underwent OPCAB grafting had a lower operative mortality than those who underwent CABG (3.3% versus 12.1%; P = .006). The mean ±SD cardiopulmonary bypass time (82.7 ± 34.7 minutes versus 160.7 ± 45.2 minutes; P < .001) and cross-clamp time (49.0 ± 22.4 minutes versus 103.4 ± 39.5 minutes; P < .001) were significantly shorter in the off-pump group than in the on-pump group. The OPCAB group also had significantly less in-hospital morbidity and shorter stays in the intensive care unit and the hospital. CONCLUSION: Our analysis shows that OPCAB grafting (compared with conventional CABG) before repairing MR is associated with favorable in-hospital outcomes for patients undergoing surgery for IMR.

Dopamine and gamma band synchrony in schizophrenia--insights from computational and empirical studies.

Dopamine modulates cortical circuit activity in part through its actions on GABAergic interneurons, including increasing the excitability of fast-spiking interneurons. Though such effects have been demonstrated in single cells, there are no studies that examine how such mechanisms may lead to the effects of dopamine at a neural network level. With this motivation, we investigated the effects of dopamine on synchronization in a simulated neural network composed of excitatory and fast-spiking inhibitory Wang-Buzsaki neurons. The effects of dopamine were implemented through varying leak K+ conductance of the fast-spiking interneurons and the network synchronization within the gamma band (∼40 Hz) was analyzed. Parametrically varying the leak K+ conductance revealed an inverted-U shaped relationship, with low gamma band power at both low and high conductance levels and optimal synchronization at intermediate conductance levels. We also examined the effects of modulating excitability of the inhibitory neurons more generically using an idealized model with theta neurons, with similar findings. Moreover, such a relationship holds when the external input is both tonic and periodic. Our computational results mirror our empirical study of dopamine modulation in schizophrenia and healthy controls, which showed that amphetamine administration increased gamma power in patients but decreased it in controls. Together, our computational and empirical investigations indicate that dopamine can modulate cortical gamma band synchrony in an inverted-U fashion and that the physiologic effects of dopamine on single fast-spiking interneurons can give rise to such non-monotonic effects at the network level.