Evaluation of the safety, accuracy, and helpfulness of the GPT-4.0 Large Language Model in neurosurgery.

BACKGROUND: Although prior work demonstrated the surprising accuracy of Large Language Models (LLMs) on neurosurgery board-style questions, their use in day-to-day clinical situations warrants further investigation. This study assessed GPT-4.0's responses to common clinical questions across various subspecialties of neurosurgery. METHODS: A panel of attending neurosurgeons formulated 35 general neurosurgical questions spanning neuro-oncology, spine, vascular, functional, pediatrics, and trauma. All questions were input into GPT-4.0 with a prespecified, standard prompt. Responses were evaluated by two attending neurosurgeons, each on a standardized scale for accuracy, safety, and helpfulness. Citations were indexed and evaluated against identifiable database references. RESULTS: GPT-4.0 responses were consistent with current medical guidelines and accounted for recent advances in the field 92.8 % and 78.6 % of the time respectively. Neurosurgeons reported GPT-4.0 responses providing unrealistic information or potentially risky information 14.3 % and 7.1 % of the time respectively. Assessed on 5-point scales, responses suggested that GPT-4.0 was clinically useful (4.0 ± 0.6), relevant (4.7 ± 0.3), and coherent (4.9 ± 0.2). The depth of clinical responses varied (3.7 ± 0.6), and "red flag" symptoms were missed 7.1 % of the time. Moreover, GPT-4.0 cited 86 references (2.46 citations per answer), of which only 50 % were deemed valid, and 77.1 % of responses contained at least one inappropriate citation. CONCLUSION: Current general LLM technology can offer generally accurate, safe, and helpful neurosurgical information, but may not fully evaluate medical literature or recent field advances. Citation generation and usage remains unreliable. As this technology becomes more ubiquitous, clinicians will need to exercise caution when dealing with it in practice.

[1-11C]-Butanol Positron Emission Tomography reveals an impaired brain to nasal turbinates pathway in aging amyloid positive subjects.

BACKGROUND: Reduced clearance of cerebrospinal fluid (CSF) has been suggested as a pathological feature of Alzheimer's disease (AD). With extensive documentation in non-human mammals and contradictory human neuroimaging data it remains unknown whether the nasal mucosa is a CSF drainage site in humans. Here, we used dynamic PET with [1-11C]-Butanol, a highly permeable radiotracer with no appreciable brain binding, to test the hypothesis that tracer drainage from the nasal pathway reflects CSF drainage from brain. As a test of the hypothesis, we examined whether brain and nasal fluid drainage times were correlated and affected by brain amyloid. METHODS: 24 cognitively normal subjects (≥ 65 years) were dynamically PET imaged for 60 min. using [1-11C]-Butanol. Imaging with either [11C]-PiB or [18F]-FBB identified 8 amyloid PET positive (Aß+) and 16 Aß- subjects. MRI-determined regions of interest (ROI) included: the carotid artery, the lateral orbitofrontal (LOF) brain, the cribriform plate, and an All-turbinate region comprised of the superior, middle, and inferior turbinates. The bilateral temporalis muscle and jugular veins served as control regions. Regional time-activity were used to model tracer influx, egress, and AUC. RESULTS: LOF and All-turbinate 60 min AUC were positively associated, thus suggesting a connection between the brain and the nose. Further, the Aß+ subgroup demonstrated impaired tracer kinetics, marked by reduced tracer influx and slower egress. CONCLUSION: The data show that tracer kinetics for brain and nasal turbinates are related to each other and both reflect the amyloid status of the brain. As such, these data add to evidence that the nasal pathway is a potential CSF drainage site in humans. These data warrant further investigation of brain and nasal contributions to protein clearance in neurodegenerative disease.

Elevated risk of recurrence and retreatment for silent pituitary adenomas.

PURPOSE: Pituitary adenomas are the most common tumor of the pituitary gland and comprise nearly 15% of all intracranial masses. These tumors are stratified into functional or silent categories based on their pattern of hormone expression and secretion. Preliminary evidence supports differential clinical outcomes between some functional pituitary adenoma (FPA) subtypes and silent pituitary adenoma (SPA) subtypes. METHODS: We collected and analyzed the medical records of all patients undergoing resection of SPAs or FPAs from a single high-volume neurosurgeon between 2007 and 2018 at Brigham and Women's Hospital. Descriptive statistics and the Mantel-Cox log-rank test were used to identify differences in outcomes between these cohorts, and multivariate logistic regression was used to identify predictors of radiographic recurrence for SPAs. RESULTS: Our cohort included 88 SPAs and 200 FPAs. The majority of patients in both cohorts were female (48.9% of SPAs and 63.5% of FPAs). SPAs were larger in median diameter than FPAs (2.1 cm vs. 1.2 cm, p < 0.001). The most frequent subtypes of SPA were gonadotrophs (55.7%) and corticotrophs (30.7%). Gross total resection (GTR) was achieved in 70.1% of SPA resections and 86.0% of FPA resections (p < 0.001). SPAs had a higher likelihood of recurring (hazard ratio [HR] 3.2, 95% confidence interval [95%CI] 1.6-7.2) and a higher likelihood of requiring retreatment for recurrence (HR 2.5; 95%CI 1.0-6.1). Subset analyses revealed that recurrence and retreatment were more both likely for subtotally resected SPAs than subtotally resected FPAs, but this pattern was not observed in SPAs and FPAs after GTR. Among SPAs, recurrence was associated with STR (odds ratio [OR] 9.3; 95%CI 1.4-64.0) and younger age (OR 0.92 per year; 95%CI 0.88-0.98) in multivariable analysis. Of SPAs that recurred, 12 of 19 (63.2%) were retreated with repeat surgery (n = 11) or radiosurgery (n = 1), while the remainder were observed (n = 7).There were similar rates of recurrence across different SPA subtypes. CONCLUSION: Patients undergoing resection of SPAs should be closely monitored for disease recurrence through more frequent clinical follow-up and diagnostic imaging than other adenomas, particularly among patients with STR and younger patients. Several patients can be observed after radiographic recurrence, and the decision to retreat should be individualized. Longitudinal clinical follow-up of SPAs, including an assessment of symptoms, endocrine function, and imaging remains critical.

Potential Mechanisms of Precision Nutrition-Based Interventions for Managing Obesity.

Precision nutrition (PN) considers multiple individual-level and environmental characteristics or variables to better inform dietary strategies and interventions for optimizing health, including managing obesity and metabolic disorders. Here, we review the evidence on potential mechanisms-including ones to identify individuals most likely to respond-that can be leveraged in the development of PN interventions addressing obesity. We conducted a review of the literature and included laboratory, animal, and human studies evaluating biochemical and genetic data, completed and ongoing clinical trials, and public programs in this review. Our analysis describes the potential mechanisms related to 6 domains including genetic predisposition, circadian rhythms, physical activity and sedentary behavior, metabolomics, the gut microbiome, and behavioral and socioeconomic characteristics, i.e., the factors that can be leveraged to design PN-based interventions to prevent and treat obesity-related outcomes such as weight loss or metabolic health as laid out by the NIH 2030 Strategic Plan for Nutrition Research. For example, single nucleotide polymorphisms can modify responses to certain dietary interventions, and epigenetic modulation of obesity risk via physical activity patterns and macronutrient intake have also been demonstrated. Additionally, we identified limitations including questions of equitable implementation across a limited number of clinical trials. These include the limited ability of current PN interventions to address systemic influences such as supply chains and food distribution, healthcare systems, racial or cultural inequities, and economic disparities, particularly when designing and implementing PN interventions in low- and middle-income communities. PN has the potential to help manage obesity by addressing intra- and inter-individual variation as well as context, as opposed to "one-size fits all" approaches though there is limited clinical trial evidence to date.

Utility of cortical tissue analysis in normal pressure hydrocephalus.

Clinical improvement following neurosurgical cerebrospinal fluid shunting for presumed idiopathic normal pressure hydrocephalus is variable. Idiopathic normal pressure hydrocephalus patients may have undetected Alzheimer's disease-related cortical pathology that confounds diagnosis and clinical outcomes. In this study, we sought to determine the utility of cortical tissue immuno-analysis in predicting shunting outcomes in idiopathic normal pressure hydrocephalus patients. We performed a pooled analysis using a systematic review as well as analysis of a new, original patient cohort. Of the 2707 screened studies, 3 studies with a total of 229 idiopathic normal pressure hydrocephalus patients were selected for inclusion in this meta-analysis alongside our original cohort. Pooled statistics of shunting outcomes for the 229 idiopathic normal pressure hydrocephalus patients and our new cohort of 36 idiopathic normal pressure hydrocephalus patients revealed that patients with Aß + pathology were significantly more likely to exhibit shunt nonresponsiveness than patients with negative pathology. Idiopathic normal pressure hydrocephalus patients with Alzheimer's disease -related cortical pathology may be at a higher risk of treatment facing unfavorable outcomes following cerebrospinal fluid shunting. Thus, cortical tissue analysis from living patients may be a useful diagnostic and prognostic adjunct for patients with presumed idiopathic normal pressure hydrocephalus and potentially other neurodegenerative conditions affecting the cerebral cortex.

The "microcephalic hydrocephalus" paradox as a paradigm of altered neural stem cell biology.

Characterized by enlarged brain ventricles, hydrocephalus is a common neurological disorder classically attributed to a primary defect in cerebrospinal fluid (CSF) homeostasis. Microcephaly ("small head") and hydrocephalus are typically viewed as two mutually exclusive phenomenon, since hydrocephalus is thought of as a fluid "plumbing" disorder leading to CSF accumulation, ventricular dilatation, and resultant macrocephaly. However, some cases of hydrocephalus can be associated with microcephaly. Recent work in the genomics of congenital hydrocephalus (CH) and an improved understanding of the tropism of certain viruses such as Zika and cytomegalovirus are beginning to shed light into the paradox "microcephalic hydrocephalus" by defining prenatal neural stem cells (NSC) as the spatiotemporal "scene of the crime." In some forms of CH and viral brain infections, impaired fetal NSC proliferation leads to decreased neurogenesis, cortical hypoplasia and impaired biomechanical interactions at the CSF-brain interface that collectively engender ventriculomegaly despite an overall and often striking decrease in head circumference. The coexistence of microcephaly and hydrocephalus suggests that these two phenotypes may overlap more than previously appreciated. Continued study of both conditions may be unexpectedly fertile ground for providing new insights into human NSC biology and our understanding of neurodevelopmental disorders.

Characterizing complications associated with skull clamps: A review of the manufacturer and user facility device experience database.

OBJECTIVE: Head immobilization with skull clamps is a prerequisite of many neurosurgical procedures. Adverse events relating to the use of skull clamps have been reported, however, given the paucity of published reports, we sought to conduct a more comprehensive analysis using the Manufacturer and User Facility Device Experience (MAUDE) database. METHODS: The MAUDE database was queried for neurosurgical skull clamp events over a 10-year period between January 2013 and December 2022. Reports were qualitatively analyzed and categorically assigned by the study authors as 'mechanical failure,' 'slippage,' 'contamination,' 'insufficient information,' and 'other.' Patient injury reports were also classified as 'abrasion,' 'laceration,' 'hematoma,' 'fracture,' 'intracranial hemorrhage (ICH),' 'other,' 'insufficient information,' and 'death.' RESULTS: Of 3672 reports retrieved, 2689 (73.2%) were device malfunctions, with mechanical failure (50.7%) and slippage (47.7%) being the most common causes. There were 983 reports (26.8%) involving patient injury which included lacerations (n = 776, 78.9%), fractures (n = 24, 2.4%), abrasions (n = 23, 2.3%), hematomas (n = 7, 0.71%), ICH (n = 3, 0.31%), and other causes (n = 6, 0.61%). Five (0.1%) deaths due to skull clamp related complications were also reported. CONCLUSIONS: This study provides a more comprehensive picture of adverse events in neurosurgical procedures relating to the use of skull clamps. Mechanical failures of device parts were the most common device-related complication, and lacerations the most common adverse patient-related event. While more severe patient-related events were reported, they are relatively rare. The MAUDE database is useful for characterizing underreported device-related and patient-related adverse events.

A systematic review of the impacts of post-harvest handling on provitamin A, iron and zinc retention in seven biofortified crops.

Post-harvest handling can affect micronutrient retention in biofortified crops through to the point of consumption. Here we conduct a systematic review identifying 67 articles examining the retention of micronutrients in conventionally bred biofortified maize, orange sweet potato, cassava, pearl millet, rice, beans and wheat. Provitamin A crops maintain high amounts compared with non-biofortified counterparts. Iron and zinc crops have more variability in micronutrient retention dependent on processing method; for maximum iron and zinc content, whole grain product consumption such as whole wheat flour or only slightly milled brown rice is beneficial. We offer preliminary suggestions for households, regulatory bodies and programme implementers to increase consumer awareness on best practices for preparing crops to maximize micronutrient content, while highlighting gaps in the literature. Our online, interactive Micronutrient Retention Dashboard ( https://www.cpnh.cornell.edu/mn-retention-db ) offers an at-a-glance view of the compiled minimum and maximum retention found, organized by processing method.

Molecular Diagnostic Yield of Exome Sequencing in Patients With Congenital Hydrocephalus: A Systematic Review and Meta-Analysis.

Importance: Exome sequencing (ES) has been established as the preferred first line of diagnostic testing for certain neurodevelopmental disorders, such as global developmental delay and autism spectrum disorder; however, current recommendations are not specific to or inclusive of congenital hydrocephalus (CH). Objective: To determine the diagnostic yield of ES in CH and whether ES should be considered as a first line diagnostic test for CH. Data Sources: PubMed, Cochrane Library, and Google Scholar were used to identify studies published in English between January 1, 2010, and April 10, 2023. The following search terms were used to identify studies: congenital hydrocephalus, ventriculomegaly, cerebral ventriculomegaly, primary ventriculomegaly, fetal ventriculomegaly, prenatal ventriculomegaly, molecular analysis, genetic cause, genetic etiology, genetic testing, exome sequencing, whole exome sequencing, genome sequencing, microarray, microarray analysis, and copy number variants. Study Selection: Eligible studies included those with at least 10 probands with the defining feature of CH and/or severe cerebral ventriculomegaly that had undergone ES. Studies with fewer than 10 probands, studies of mild or moderate ventriculomegaly, and studies using genetic tests other than ES were excluded. A full-text review of 68 studies was conducted by 2 reviewers. Discrepancies were resolved by consensus. Data Extraction and Synthesis: Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Meta-Analysis of Observational Studies in Epidemiology guidelines were used by 2 reviewers to extract data. Data were synthesized using a random-effects model of single proportions. Data analysis occurred in April 2023. Main Outcomes and Measures: The primary outcome was pooled diagnostic yield. Additional diagnostic yields were estimated for specific subgroups on the basis of clinical features, syndromic presentation, and parental consanguinity. For each outcome, a 95% CI and estimate of interstudy heterogeneity (I2 statistic) was reported. Results: From 498 deduplicated and screened records, 9 studies with a total of 538 CH probands were selected for final inclusion. The overall diagnostic yield was 37.9% (95% CI, 20.0%-57.4%; I2 = 90.1). The yield was lower for isolated and/or nonsyndromic cases (21.3%; 95% CI, 12.8%-31.0%; I2 = 55.7). The yield was higher for probands with reported consanguinity (76.3%; 95% CI, 65.1%-86.1%; I2 = 0) than those without (16.2%; 95% CI, 12.2%-20.5%; I2 = 0). Conclusions and Relevance: In this systematic review and meta-analysis of the diagnostic yield of ES in CH, the diagnostic yield was concordant with that of previous recommendations for other neurodevelopmental disorders, suggesting that ES should also be recommended as a routine diagnostic adjunct for patients with CH.

Human genetics and molecular genomics of Chiari malformation type 1.

Chiari malformation type 1 (CM1) is the most common structural brain disorder involving the craniocervical junction, characterized by caudal displacement of the cerebellar tonsils below the foramen magnum into the spinal canal. Despite the heterogeneity of CM1, its poorly understood patho-etiology has led to a 'one-size-fits-all' surgical approach, with predictably high rates of morbidity and treatment failure. In this review we present multiplex CM1 families, associated Mendelian syndromes, and candidate genes from recent whole exome sequencing (WES) and other genetic studies that suggest a significant genetic contribution from inherited and de novo germline variants impacting transcription regulation, craniovertebral osteogenesis, and embryonic developmental signaling. We suggest that more extensive WES may identify clinically relevant, genetically defined CM1 subtypes distinguished by unique neuroradiographic and neurophysiological endophenotypes.

Cases of familial idiopathic normal pressure hydrocephalus implicate genetic factors in disease pathogenesis.

Idiopathic normal pressure hydrocephalus is a disorder of unknown pathophysiology whose diagnosis is paradoxically made by a positive response to its proposed treatment with cerebrospinal fluid diversion. There are currently no idiopathic normal pressure hydrocephalus disease genes or biomarkers. A systematic analysis of familial idiopathic normal pressure hydrocephalus could aid in clinical diagnosis, prognosis, and treatment stratification, and elucidate disease patho-etiology. In this 2-part analysis, we review literature-based evidence for inheritance of idiopathic normal pressure hydrocephalus in 22 pedigrees, and then present a novel case series of 8 familial idiopathic normal pressure hydrocephalus patients. For the case series, demographics, familial history, pre- and post-operative symptoms, and cortical pathology were collected. All novel familial idiopathic normal pressure hydrocephalus patients exhibited improvement following shunt treatment and absence of neurodegenerative cortical pathology (amyloid-beta and hyperphosphorylated tau), in contrast to many sporadic cases of idiopathic normal pressure hydrocephalus with variable clinical responses. Analysis of the 30 total familial idiopathic normal pressure hydrocephalus cases reported herein is highly suggestive of an autosomal dominant mechanism of inheritance. This largest-ever presentation of multiply affected idiopathic normal pressure hydrocephalus pedigrees provides strong evidence for Mendelian inheritance and autosomal dominant transmission of an idiopathic normal pressure hydrocephalus trait in a subset of patients that positively respond to shunting and lack neurodegenerative pathology. Genomic investigation of these families may identify the first bona fide idiopathic normal pressure hydrocephalus disease gene.

Sensory acceptability of biofortified foods and food products: a systematic review.

CONTEXT: It is important to understand the sensory acceptability of biofortified food products among target population groups if biofortification is to be realized as a sustainable strategy for mitigation of micronutrient deficiencies, able to be scaled up and applied through programs. OBJECTIVE: This systemic review aims to summarize and synthesize the sensory acceptability of conventionally bred iron-, zinc-, and provitamin A-biofortified food products. DATA SOURCES: MEDLINE (PubMed), AGRICOLA, AgEcon, CABI Abstracts (Web of Science), and organizational websites (eg, those of HarvestPlus and CGIAR and their partners) were searched for relevant articles. No access to any market research that may have been internally conducted for the commercial biofortified food products was available. DATA EXTRACTION: This review identified articles measuring the sensory acceptability of conventionally bred biofortified food products. Extraction of the hedonic ratings of food products was performed. DATA ANALYSIS: An "Acceptability Index %" was defined based on hedonic scoring to determine an overall rating, and used to categorize biofortified food products as "acceptable" (≥70%) or "not acceptable" (<70%). Additionally, this review narratively synthesized studies using methods other than hedonic scoring for assessing sensory acceptability. CONCLUSIONS: Forty-nine studies assessed the acceptability of 10 biofortified crops among children and adults, in mostly rural, low-income settings across Africa, Latin America, and India; food products made from mineral and provitamin A-biofortified food products were generally acceptable. Compared with studies on provitamin-A biofortified food products, few studies (1 to 2 each) on mineral-enhanced crops such as rice, cowpeas, lentils, and wheat were found, limiting the generalizability of the findings. Similarly, few studies examined stored biofortified food products. Few commercial food products have so far been developed, although new varieties of crops are being continuously tested and released globally. Certain crop varieties were found to be acceptable while others were not, suggesting that particular varieties should be prioritized for scale-up. Determining sensory acceptability of biofortified food products is important for informing programmatic scale-up and implementation across diverse populations and settings.

The Efficacy of Endoscopic Third Ventriculostomy for Idiopathic Normal Pressure Hydrocephalus.

Recently, intervention with endoscopic third ventriculostomy (ETV) for patients with idiopathic normal pressure hydrocephalus (iNPH) has emerged as a potential minimally invasive alternative to traditional treatments (ventriculoperitoneal shunting). The clinical response to these interventions is variable and unclear. The objective of this review was to assess the efficacy of endoscopic third ventriculostomy in treating patients with iNPH. A systematic review of PubMed, Web of Science, and Google Scholar was conducted using search terms relevant to ETV and iNPH. Included studies met consistent, predetermined diagnostic criteria for iNPH, implemented ETV in subjects greater than 40 years of age, and assessed all 3 components of Hakim's triad (gait impairment, dementia, and incontinence). Data extraction included dichotomization of successful ETV clinical outcomes and a subgroup meta-analysis of ETV success rates across binarized age groups. Meta-analysis was conducted using a Mantel-Haenszel fixed-effects model. The outcomes presented include generalized ETV success rates across all 12 studies. Age-specific individual data was measured with odds ratios, with a pooled statistic measured using the Mantel-Haenszel test. Overall, 2294 studies were identified in this search, of which 12 were selected for inclusion in this systematic review. Of these, 3 studies were utilized for age-specific meta-analyses. Preliminary synthesis of ETV clinical outcomes across all 12 studies revealed a success rate of 60.2%. Additionally, meta-analysis revealed that iNPH patients younger than or equal to 65 years of age were significantly more likely to respond successfully to ETV intervention. Heterogeneity was inconsequential in this analysis.

Sonodynamic Therapy and Sonosensitizers for Glioma Treatment: A Systematic Qualitative Review.

Sonodynamic therapy (SDT) has emerged as an encouraging noninvasive technique that uses ultrasound to activate targeted agents to induce antitumor effects for the treatment of glioma. With extensive variation in the types of sonosensitizers, protocols for sonication, and model systems, a comprehensive overview of existing preclinical data on the efficacy of SDT in glioma treatment is warranted. Here, we conduct a systematic review of preclinical and early clinical literature on implementing SDT to treat in vitro and in vivo models of glioma. Our findings suggest that coupling sonosensitizers such as 5-aminolevulinic acid, hematoporphyrin monomethyl ether, and sinoporphyrin sodium with focused ultrasound induces robust cytotoxic activity in tumor cells (in vitro and in vivo). These effects are likely mediated by the oxidative stress induced by reactive oxygen species production, apoptotic signaling cascades, and intracellular calcium overload. Future research is needed to better understand the biochemical and mechanistic properties of SDT, and ongoing trials may help elucidate the clinical feasibility of glioma treatment with optimized sonically activated treatments.

Sonolucent cranioplasty: Is therapeutic FUS the next frontier?

Focused ultrasound (FUS) has emerged as a promising area of research in neuro-oncology. Preclinical and clinical investigation has demonstrated the utility of FUS in therapeutic applications including blood brain barrier disruption for therapeutic delivery, and high intensity FUS for tumor ablation. However, FUS as it exists today is relatively invasive as implantable devices are necessary to achieve adequate intracranial penetration. Sonolucent implants, composed of materials permeable to acoustic waves, have been used for cranioplasty and intracranial imaging with ultrasound. Given the overlap in ultrasound parameters with those used for intracranial imaging, and the demonstrated efficacy of sonolucent cranial implants, we believe that therapeutic FUS through sonolucent implants represents a promising avenue of future research. The potential applications of FUS and sonolucent cranial implants may confer the demonstrated therapeutic benefits of existing FUS applications, without the drawbacks and complications of invasive implantable devices. Here we briefly summarize existing evidence regarding sonolucent implants and describe applications for therapeutic FUS.

Peripheral immune cell imbalance is associated with cortical beta-amyloid deposition and longitudinal cognitive decline.

Neuroinflammation is believed to be a key process in Alzheimer's disease (AD) pathogenesis. Recently, the neutrophil-to-lymphocyte (NLR) and lymphocyte-to-monocyte ratios (LMR) have been proposed to be useful peripheral markers of inflammation. However, it is unclear how these inflammatory ratios relate to AD pathology, such as ß-amyloid (Aß) plaques and tau tangles. Using 18F-florbetapir and 18F-flortaucipir positron emission tomography (PET), we sought to determine how the NLR and LMR are associated with AD pathology both cross-sectionally and longitudinally. We further evaluated associations between the NLR and LMR and longitudinal cognitive decline. Using data from the Alzheimer's Disease Neuroimaging Initiative, we analyzed blood, PET, and cognitive data from 1544 subjects-405 cognitively normal, 838 with mild cognitive impairment (MCI), and 301 with AD. Associations between the NLR and LMR and Aß and tau on PET were assessed using ordinary least-squares and mixed-effects regression models, while adjusting for age, sex, years of education, and apolipoprotein E ε2 or ε4 carrier status. Associations between the NLR and LMR and cognitive function, as measured by the AD Assessment Scale-Cognitive Subscale, 13-item version, were also assessed. MCI and AD subjects had higher NLR (p = 0.017, p < 0.001, respectively) and lower LMR (p = 0.013, p = 0.023). The NLR, but not the LMR, was significantly associated with Aß (p = 0.028), suggesting that higher NLR was associated with greater Aß deposition in the brain. Neither the NLR nor the LMR was associated with tau deposition (p > 0.05). A higher NLR was associated with greater longitudinal cognitive decline (p < 0.001). A higher ratio of peripheral neutrophils to lymphocytes, possibly reflecting an imbalance in innate versus adaptive immunity, is related to greater Aß deposition and longitudinal cognitive decline. As the field moves toward blood-based biomarkers of AD, the altered balance of innate versus adaptive immunity could be a useful biomarker of underlying pathology and may also serve as a potential therapeutic target.

Bioaccessibility and bioavailability of biofortified food and food products: Current evidence.

Biofortification increases micronutrient content in staple crops through conventional breeding, agronomic methods, or genetic engineering. Bioaccessibility is a prerequisite for a nutrient to fulfill a biological function, e.g., to be bioavailable. The objective of this systematic review is to examine the bioavailability (and bioaccessibility as a proxy via in vitro and animal models) of the target micronutrients enriched in conventionally biofortified crops that have undergone post-harvest storage and/or processing, which has not been systematically reviewed previously, to our knowledge. We searched for articles indexed in MEDLINE, Agricola, AgEcon, and Center for Agriculture and Biosciences International databases, organizational websites, and hand-searched studies' reference lists to identify 18 studies reporting on bioaccessibility and 58 studies on bioavailability. Conventionally bred biofortified crops overall had higher bioaccessibility and bioavailability than their conventional counterparts, which generally provide more absorbed micronutrient on a fixed ration basis. However, these estimates depended on exact cultivar, processing method, context (crop measured alone or as part of a composite meal), and experimental method used. Measuring bioaccessibility and bioavailability of target micronutrients in biofortified and conventional foods is critical to optimize nutrient availability and absorption, ultimately to improve programs targeting micronutrient deficiency.

Connecting the connectome: A bibliometric investigation of the 50 most cited articles.

OBJECTIVE: Connectomics is an emerging and novel research area in neuroscience. We performed a bibliometric analysis to characterize the most impactful articles regarding connectomics, in hopes of evaluating the current state of the field and guiding future research. METHODS: The Web of Science ™ database was queried to identify the 50 most cited articles regarding brain connectomics. Publication meta-data, including country of origin, journal of publication, citation count, and year of publication were extracted and analyzed. Studies were qualitatively analyzed to characterize the goals and area of research. RESULTS: The top 50 cited articles were published between 2005 and 2018, with a majority revolving around MRI acquisition and down-stream processing (n = 24, 48%). Articles were published in journals with an average impact factor of 16.5 and averaged a citation count of 1019 (+ 627.2). Most articles originated from the United States (n = 27, 54%) displayed level II (n = 18, 36%) or level V (n = 20, 40%) evidence. CONCLUSION: The Human Connectome Project in 2009 spurred widespread research on functional brain connectivity, and the effort to understand the functional networks and connections of the nervous system remains an area of exciting potential. Despite much work done to understand image acquisition and analysis, a renewed appreciation for the wide clinical application of connectomics is warranted. Our analysis helps contextualize the most relevant scientific work on brain connectomics, providing insights for the future for connectomics research.

Quantifying cerebrospinal fluid dynamics: A review of human neuroimaging contributions to CSF physiology and neurodegenerative disease.

Cerebrospinal fluid (CSF), predominantly produced in the ventricles and circulating throughout the brain and spinal cord, is a key protective mechanism of the central nervous system (CNS). Physical cushioning, nutrient delivery, metabolic waste, including protein clearance, are key functions of the CSF in humans. CSF volume and flow dynamics regulate intracranial pressure and are fundamental to diagnosing disorders including normal pressure hydrocephalus, intracranial hypotension, CSF leaks, and possibly Alzheimer's disease (AD). The ability of CSF to clear normal and pathological proteins, such as amyloid-beta (Aß), tau, alpha synuclein and others, implicates it production, circulation, and composition, in many neuropathologies. Several neuroimaging modalities have been developed to probe CSF fluid dynamics and better relate CSF volume and flow to anatomy and clinical conditions. Approaches include 2-photon microscopic techniques, MRI (tracer-based, gadolinium contrast, endogenous phase-contrast), and dynamic positron emission tomography (PET) using existing approved radiotracers. Here, we discuss CSF flow neuroimaging, from animal models to recent clinical-research advances, summarizing current endeavors to quantify and map CSF flow with implications towards pathophysiology, new biomarkers, and treatments of neurological diseases.

Review of the Impact Pathways of Biofortified Foods and Food Products.

Biofortification is the process of increasing the concentrations and/or bioavailability of micronutrients in staple crops and has the potential to mitigate micronutrient deficiencies globally. Efficacy trials have demonstrated benefits of consuming biofortified crops (BFCs); and in this paper, we report on the results of a systematic review of biofortified crops effectiveness in real-world settings. We synthesized the evidence on biofortified crops consumption through four Impact Pathways: (1) purchased directly; (2) in informal settings; (3) in formal settings; or (4) in farmer households, from their own production. Twenty-five studies, covering Impact Pathway 1 (five studies), Impact Pathway 2 (three), Impact Pathway 3 (three), Impact Pathway 4 (21) were included. The review found evidence of an improvement in micronutrient status via Impact Pathway 4 (mainly in terms of vitamin A from orange sweet potato) in controlled interventions that involved the creation of demand, the extension of agriculture and promotion of marketing. In summary, evidence supports that biofortified crops can be part of food systems interventions to reduce micronutrient deficiencies in farmer households; ongoing and future research will help fully inform their potential along the other three Impact Pathways for scaling up.