UW Neurological Surgery Recent PubMed Publications

Multipoint Background Analysis: Gaining Precision and Accuracy in Microprobe Trace Element Analysis.

Microsc Microanal. 2019 Feb 12;:1-17

Authors: Allaz JM, Williams ML, Jercinovic MJ, Goemann K, Donovan J

Abstract
Electron microprobe trace element analysis is a significant challenge. Due to the low net intensity of peak measurements, the accuracy and precision of such analyses relies critically on background measurements, and on the accuracy of any pertinent peak interference corrections. A linear regression between two points selected at appropriate background positions is a classical approach for electron probe microanalysis (EPMA). However, this approach neglects the accurate assessment of background curvature (exponential or polynomial), and the presence of background interferences, a hole in the background, or an absorption edge can dramatically affect the results if underestimated or ignored. The acquisition of a quantitative wavelength-dispersive spectrometry (WDS) scan over the spectral region of interest remains a reasonable option to determine the background intensity and curvature from a fitted regression of background portions of the scan, but this technique can be time consuming and retains an element of subjectivity, as the analyst has to select areas in the scan which appear to represent background. This paper presents a new multi-point background (MPB) method whereby the background intensity is determined from up to 24 background measurements from wavelength positions on either side of analytical lines. This method improves the accuracy and precision of trace element analysis in a complex matrix through careful regression of the background shape, and can be used to characterize the background over a large spectral region covering several elements to be analyzed. The overall efficiency improves as systematic WDS scanning is not required to assess background interferences. The method is less subjective compared to methods that rely on WDS scanning, including selection of two interpolation points based on WDS scans, because "true" backgrounds are selected through an exclusion method of possible erroneous backgrounds. The first validation of the MPB method involves blank testing to ensure the method can accurately measure the absence of an element. The second validation involves the analysis of U-Th-Pb in several monazite reference materials of known isotopic age. The impetus for the MPB method came from efforts to refine EPMA monazite U-Th-Pb dating, where it was recognized that background errors resulting from interference or strong background curvature could result in errors of several tens of millions of years on the calculated date. Results obtained on monazite reference materials using two different microprobes, a Cameca SX-100 Ultrachron and a JEOL JXA-8230, yield excellent agreement with ages obtained by isotopic methods (Thermal Ionization Mass Spectrometry [TIMS], Sensitive High-Resolution Ion MicroProbe [SHRIMP], or Secondary Ion Mass Spectrometry [SIMS]). Finally, the MPB method can be used to model the background over a large spectrometer range to improve the accuracy of background measurement of minor and trace elements acquired on a same spectrometer, a method called the shared background measurement. This latter significantly improves the accuracy of minor and trace element analysis in complex matrices, as demonstrated by the analysis of Rare Earth Elements (REE) in REE-silicates and phosphates and of trace elements in scheelite.

PMID: 30744721 [PubMed - as supplied by publisher]

Matching early arterial oxygenation to long-term outcome in severe traumatic brain injury: target values.

J Neurosurg. 2019 02 08;132(2):537-544

Authors: Alali AS, Temkin N, Vavilala MS, Lele AV, Barber J, Dikmen S, Chesnut RM

Abstract
OBJECTIVE: The aim of this study was to examine the relationship between early arterial oxygenation thresholds and long-term outcome after severe traumatic brain injury (TBI).
METHODS: In a post hoc analysis of a randomized trial, adults with severe TBI were classified based on exposure to different levels of arterial oxygenation as measured using the average of arterial partial pressure of oxygen (PaO2) values obtained within 24 hours of admission. Potentially important PaO2 thresholds were defined a priori. The primary outcome was Glasgow Outcome Scale-Extended (GOSE) score at 6 months. Secondary outcomes were cognitive outcomes measured using a battery of 9 neuropsychological tests administered at 6 months, and 6-month mortality.
RESULTS: In adjusted analyses, oxygenation thresholds of 150 and 200 mm Hg were associated with better functional outcome at 6 months (adjusted OR for better functional outcome on GOSE 1.82 [95% CI 1.12-2.94] and 1.59 [95% CI 1.06-2.37], respectively) and improved cognitive outcome at 6 months (adjusted beta coefficients for better cognitive percentile across 9 neuropsychological tests: 6.9 [95% CI 1.3-12.5] and 6.8 [95% CI 2.4-11.3], respectively). There was no significant association between oxygenation level and 6-month mortality except at a PaO2 threshold of 200 mm Hg (OR for death 0.36, 95% CI 0.18-0.71). Higher or lower oxygenation thresholds were not associated with functional or cognitive outcome.
CONCLUSIONS: In this observational study, the relationship between early arterial oxygenation and long-term functional and cognitive TBI outcomes appears to be U-shaped. Mild levels of hyperoxemia within the first 24 hours after injury were associated with better long-term functional and cognitive outcomes. These findings highlight the importance of examining balanced oxygen supplementation as a potential strategy to improve TBI outcomes in future research.

PMID: 30738409 [PubMed - indexed for MEDLINE]

Challenges to curing primary brain tumours.

Nat Rev Clin Oncol. 2019 08;16(8):509-520

Authors: Aldape K, Brindle KM, Chesler L, Chopra R, Gajjar A, Gilbert MR, Gottardo N, Gutmann DH, Hargrave D, Holland EC, Jones DTW, Joyce JA, Kearns P, Kieran MW, Mellinghoff IK, Merchant M, Pfister SM, Pollard SM, Ramaswamy V, Rich JN, Robinson GW, Rowitch DH, Sampson JH, Taylor MD, Workman P, Gilbertson RJ

Abstract
Despite decades of research, brain tumours remain among the deadliest of all forms of cancer. The ability of these tumours to resist almost all conventional and novel treatments relates, in part, to the unique cell-intrinsic and microenvironmental properties of neural tissues. In an attempt to encourage progress in our understanding and ability to successfully treat patients with brain tumours, Cancer Research UK convened an international panel of clinicians and laboratory-based scientists to identify challenges that must be overcome if we are to cure all patients with a brain tumour. The seven key challenges summarized in this Position Paper are intended to serve as foci for future research and investment.

PMID: 30733593 [PubMed - indexed for MEDLINE]

Mild Traumatic Brain Injury and Mental Health-Reply.

JAMA Neurol. 2017 11 01;74(11):1378

Authors: Mac Donald CL, Fann JR, Temkin NR

PMID: 29049812 [PubMed - indexed for MEDLINE]

Cerebellar tonsil ectopia measurement in type I Chiari malformation patients show poor inter-operator reliability.

Fluids Barriers CNS. 2018 Dec 17;15(1):33

Authors: Lawrence BJ, Urbizu A, Allen PA, Loth F, Tubbs RS, Bunck AC, Kröger JR, Rocque BG, Madura C, Chen JA, Luciano MG, Ellenbogen RG, Oshinski JN, Iskandar BJ, Martin BA

Abstract
BACKGROUND: Type 1 Chiari malformation (CM-I) has been historically defined by cerebellar tonsillar position (TP) greater than 3-5 mm below the foramen magnum (FM). Often, the radiographic findings are highly variable, which may influence the clinical course and patient outcome. In this study, we evaluate the inter-operator reliability (reproducibility) of MRI-based measurement of TP in CM-I patients and healthy controls.
METHODS: Thirty-three T2-weighted MRI sets were obtained for 23 CM-I patients (11 symptomatic and 12 asymptomatic) and 10 healthy controls. TP inferior to the FM was measured in the mid-sagittal plane by seven expert operators with reference to McRae's line. Overall agreement between the operators was quantified by intraclass correlation coefficient (ICC).
RESULTS: The mean and standard deviation of cerebellar TP measurements for asymptomatic (CM-Ia) and symptomatic (CM-Is) patients in mid-sagittal plane was 6.38 ± 2.19 and 9.57 ± 2.63 mm, respectively. TP measurements for healthy controls was 0.48 ± 2.88 mm. The average range of TP measurements for all data sets analyzed was 7.7 mm. Overall operator agreement for TP measurements was relatively high with an ICC of 0.83.
CONCLUSION: The results demonstrated a large average range (7.7 mm) of measurements among the seven expert operators and support that, if economically feasible, two radiologists should make independent measurements before radiologic diagnosis of CM-I and surgery is contemplated. In the future, an objective diagnostic parameter for CM-I that utilizes automated algorithms and results in smaller inter-operator variation may improve patient selection.

PMID: 30554565 [PubMed - indexed for MEDLINE]

Incorporating media data into a model of infectious disease transmission.

PLoS One. 2019;14(2):e0197646

Authors: Kim L, Fast SM, Markuzon N

Abstract
Understanding the effect of media on disease spread can help improve epidemic forecasting and uncover preventive measures to slow the spread of disease. Most previously introduced models have approximated media effect through disease incidence, making media influence dependent on the size of epidemic. We propose an alternative approach, which relies on real data about disease coverage in the news, allowing us to model low incidence/high interest diseases, such as SARS, Ebola or H1N1. We introduce a network-based model, in which disease is transmitted through local interactions between individuals and the probability of transmission is affected by media coverage. We assume that media attention increases self-protection (e.g. hand washing and compliance with social distancing), which, in turn, decreases disease model. We apply the model to the case of H1N1 transmission in Mexico City in 2009 and show how media influence-measured by the time series of the weekly count of news articles published on the outbreak-helps to explain the observed transmission dynamics. We show that incorporating the media attention based on the observed media coverage of the outbreak better estimates the disease dynamics from what would be predicted by using media function that approximate the media impact using the number of cases and rate of spread. Finally, we apply the model to a typical influenza season in Washington, DC and estimate how the transmission pattern would have changed given different levels of media coverage.

PMID: 30716139 [PubMed - indexed for MEDLINE]

Resection of Meningiomas Involving Major Dural Venous Sinuses: Classification, Technique, and Long-Term Results.

World Neurosurg. 2019 05;125:e521-e536

Authors: Zeeshan Q, Patel A, Cheng CY, Zhao NH, Barber J, Ghodke BV, Sekhar LN

Abstract
OBJECTIVE: Management of meningiomas with major dural venous sinus involvement is challenging. We present our case series and perspective on reconstruction of the sinuses.
METHODS: Fifty-five patients underwent operations between 2005 and 2016 and the retrospective data were collected and analyzed.
RESULTS: The cohort was younger with a mean of 51.3 years (range, 19-72 years) predominantly involving the superior sagittal sinus (44 patients). Sinus involvement was classified into group 1 (<50% of sinus, n = 28), group 2 (50%-99%, n = 8), and group 3 (total occlusion, n = 19). Venous collateralization was present in 100% of group 2 and 3 and in 36% of group 1 occlusions. Sinus pericranii was seen in 22 patients. Gross total resection was achieved in 87.2%, and sinus reconstruction followed in 38 patients (24 by direct suture and 14 by a patch graft). Pathology showed 36 (65%) World Health Organization grade I, 18 (33%) grade II, and 1 (2%) grade III tumors. During the mean follow-up of 60 months (range, 1-132 months), sinus was patent (74%) or narrowed but patent (24%) in 98%; 2 recurrences (3.6%) were observed (at 24 and 120 months). The mean preoperative/postoperative Karnofsky Performance Status and Kaplan-Meier cumulative overall/recurrence-free survival were 84.2%/88.1% and 90.9%/80.1%, respectively.
CONCLUSIONS: These meningiomas present in a younger population, are more likely to be World Health Organization grade II or III, necessitating a more aggressive tumor resection strategy. Aggressive resection coupled with sinus reconstruction results in good long-term surgical outcome and low recurrence rates.

PMID: 30716491 [PubMed - indexed for MEDLINE]

Lactadherin promotes microvesicle clearance to prevent coagulopathy and improves survival of severe TBI mice.

Blood. 2018 02 01;131(5):563-572

Authors: Zhou Y, Cai W, Zhao Z, Hilton T, Wang M, Yeon J, Liu W, Zhang F, Shi FD, Wu X, Thiagarajan P, Li M, Zhang J, Dong JF

Abstract
Coagulopathy is common in patients with traumatic brain injury (TBI) and predicts poor clinical outcomes. We have shown that brain-derived extracellular microvesicles, including extracellular mitochondria, play a key role in the development of TBI-induced coagulopathy. Here, we further show in mouse models that the apoptotic cell-scavenging factor lactadherin, given at a single dose of 400 μg/kg 30 minutes before (preconditioning) or 30 minutes after cerebral fluid percussion injury, prevented coagulopathy as defined by clotting time, fibrinolysis, intravascular fibrin deposition, and microvascular bleeding of the lungs. Lactadherin also reduced cerebral edema, improved neurological function, and increased survival. It achieved these protective effects by enhancing the clearance of circulating microvesicles through phosphatidylserine-mediated phagocytosis. Together, these results identify the scavenging system for apoptotic cells as a potential therapeutic target to prevent TBI-induced coagulopathy and improve the outcome of TBI.

PMID: 29162596 [PubMed - indexed for MEDLINE]

Early dysregulation of cardiac-specific microRNA-208a is linked to maladaptive cardiac remodelling in diabetic myocardium.

Cardiovasc Diabetol. 2019 Jan 29;18(1):13

Authors: Rawal S, Nagesh PT, Coffey S, Van Hout I, Galvin IF, Bunton RW, Davis P, Williams MJA, Katare R

Abstract
BACKGROUND: The diabetic heart undergoes remodelling contributing to an increased incidence of heart failure in individuals with diabetes at a later stage. The molecular regulators that drive this process in the diabetic heart are still unknown.
METHODS: Real-time (RT) PCR analysis was performed to determine the expression of cardiac specific microRNA-208a in right atrial appendage (RAA) and left ventricular (LV) biopsy tissues collected from diabetic and non-diabetic patients undergoing coronary artery bypass graft surgery. To determine the time-dependent changes, cardiac tissue were collected from type 2 diabetic mice at different age groups. A western blotting analysis was conducted to determine the expression of contractile proteins α- and β-myosin heavy chain (MHC) and thyroid hormone receptor-α (TR-α), the negative regulator of β-MHC. To determine the beneficial effects of therapeutic modulation of miR-208a, high glucose treated adult mouse HL-1 cardiomyocytes were transfected with anti-miR-208a.
RESULTS: RT-PCR analysis showed marked upregulation of miR-208a from early stages of diabetes in type 2 diabetic mouse heart, which was associated with a marked increase in the expression of pro-hypertrophic β-MHC and downregulation of TR-α. Interestingly, upregulation of miR-208a preceded the switch of α-/β-MHC isoforms and the development of diastolic and systolic dysfunction. We also observed significant upregulation of miR-208a and modulation of miR-208a associated proteins in the type 2 human diabetic heart. Therapeutic inhibition of miR-208a activity in high glucose treated HL-1 cardiomyocytes prevented the activation of β-MHC and hence the hypertrophic response.
CONCLUSION: Our results provide the first evidence that early modulation of miR-208a in the diabetic heart induces alterations in the downstream signaling pathway leading to cardiac remodelling and that therapeutic inhibition of miR-208a may be beneficial in preventing diabetes-induced adverse remodelling of the heart.

PMID: 30696455 [PubMed - in process]

Risk of Posttraumatic Stress Disorder and Major Depression in Civilian Patients After Mild Traumatic Brain Injury: A TRACK-TBI Study.

JAMA Psychiatry. 2019 03 01;76(3):249-258

Authors: Stein MB, Jain S, Giacino JT, Levin H, Dikmen S, Nelson LD, Vassar MJ, Okonkwo DO, Diaz-Arrastia R, Robertson CS, Mukherjee P, McCrea M, Mac Donald CL, Yue JK, Yuh E, Sun X, Campbell-Sills L, Temkin N, Manley GT, TRACK-TBI Investigators, Adeoye O, Badjatia N, Boase K, Bodien Y, Bullock MR, Chesnut R, Corrigan JD, Crawford K, Diaz-Arrastia R, Dikmen S, Duhaime AC, Ellenbogen R, Feeser VR, Ferguson A, Foreman B, Gardner R, Gaudette E, Giacino JT, Gonzalez L, Gopinath S, Gullapalli R, Hemphill JC, Hotz G, Jain S, Korley F, Kramer J, Kreitzer N, Levin H, Lindsell C, Machamer J, Madden C, Martin A, McAllister T, McCrea M, Merchant R, Mukherjee P, Nelson LD, Noel F, Okonkwo DO, Palacios E, Perl D, Puccio A, Rabinowitz M, Robertson CS, Rosand J, Sander A, Satris G, Schnyer D, Seabury S, Sherer M, Stein MB, Taylor S, Toga A, Temkin N, Valadka A, Vassar MJ, Vespa P, Wang K, Yue JK, Yuh E, Zafonte R

Abstract
Importance: Traumatic brain injury (TBI) has been associated with adverse mental health outcomes, such as posttraumatic stress disorder (PTSD) and major depressive disorder (MDD), but little is known about factors that modify risk for these psychiatric sequelae, particularly in the civilian sector.
Objective: To ascertain prevalence of and risk factors for PTSD and MDD among patients evaluated in the emergency department for mild TBI (mTBI).
Design, Setting, and Participants: Prospective longitudinal cohort study (February 2014 to May 2018). Posttraumatic stress disorder and MDD symptoms were assessed using the PTSD Checklist for DSM-5 and the Patient Health Questionnaire-9 Item. Risk factors evaluated included preinjury and injury characteristics. Propensity score weights-adjusted multivariable logistic regression models were performed to assess associations with PTSD and MDD. A total of 1155 patients with mTBI (Glasgow Coma Scale score, 13-15) and 230 patients with nonhead orthopedic trauma injuries 17 years and older seen in 11 US hospitals with level 1 trauma centers were included in this study.
Main Outcomes and Measures: Probable PTSD (PTSD Checklist for DSM-5 score, ≥33) and MDD (Patient Health Questionnaire-9 Item score, ≥15) at 3, 6, and 12 months postinjury.
Results: Participants were 1155 patients (752 men [65.1%]; mean [SD] age, 40.5 [17.2] years) with mTBI and 230 patients (155 men [67.4%]; mean [SD] age, 40.4 [15.6] years) with nonhead orthopedic trauma injuries. Weights-adjusted prevalence of PTSD and/or MDD in the mTBI vs orthopedic trauma comparison groups at 3 months was 20.0% (SE, 1.4%) vs 8.7% (SE, 2.2%) (P < .001) and at 6 months was 21.2% (SE, 1.5%) vs 12.1% (SE, 3.2%) (P = .03). Risk factors for probable PTSD at 6 months after mTBI included less education (adjusted odds ratio, 0.89; 95% CI, 0.82-0.97 per year), being black (adjusted odds ratio, 5.11; 95% CI, 2.89-9.05), self-reported psychiatric history (adjusted odds ratio, 3.57; 95% CI, 2.09-6.09), and injury resulting from assault or other violence (adjusted odds ratio, 3.43; 95% CI, 1.56-7.54). Risk factors for probable MDD after mTBI were similar with the exception that cause of injury was not associated with increased risk.
Conclusions and Relevance: After mTBI, some individuals, on the basis of education, race/ethnicity, history of mental health problems, and cause of injury were at substantially increased risk of PTSD and/or MDD. These findings should influence recognition of at-risk individuals and inform efforts at surveillance, follow-up, and intervention.

PMID: 30698636 [PubMed - indexed for MEDLINE]

Metabolic and Organelle Morphology Defects in Mice and Human Patients Define Spinocerebellar Ataxia Type 7 as a Mitochondrial Disease.

Cell Rep. 2019 01 29;26(5):1189-1202.e6

Authors: Ward JM, Stoyas CA, Switonski PM, Ichou F, Fan W, Collins B, Wall CE, Adanyeguh I, Niu C, Sopher BL, Kinoshita C, Morrison RS, Durr A, Muotri AR, Evans RM, Mochel F, La Spada AR

Abstract
Spinocerebellar ataxia type 7 (SCA7) is a retinal-cerebellar degenerative disorder caused by CAG-polyglutamine (polyQ) repeat expansions in the ataxin-7 gene. As many SCA7 clinical phenotypes occur in mitochondrial disorders, and magnetic resonance spectroscopy of patients revealed altered energy metabolism, we considered a role for mitochondrial dysfunction. Studies of SCA7 mice uncovered marked impairments in oxygen consumption and respiratory exchange. When we examined cerebellar Purkinje cells in mice, we observed mitochondrial network abnormalities, with enlarged mitochondria upon ultrastructural analysis. We developed stem cell models from patients and created stem cell knockout rescue systems, documenting mitochondrial morphology defects, impaired oxidative metabolism, and reduced expression of nicotinamide adenine dinucleotide (NAD+) production enzymes in SCA7 models. We observed NAD+ reductions in mitochondria of SCA7 patient NPCs using ratiometric fluorescent sensors and documented alterations in tryptophan-kynurenine metabolism in patients. Our results indicate that mitochondrial dysfunction, stemming from decreased NAD+, is a defining feature of SCA7.

PMID: 30699348 [PubMed - indexed for MEDLINE]

Autophagy modulates lipid metabolism to maintain metabolic flexibility for Lkb1-deficient Kras-driven lung tumorigenesis.

Genes Dev. 2019 02 01;33(3-4):150-165

Authors: Bhatt V, Khayati K, Hu ZS, Lee A, Kamran W, Su X, Guo JY

Abstract
Loss of tumor suppressor liver kinase B1 (LKB1) promotes cancer cell proliferation but also leads to decreased metabolic plasticity in dealing with energy crises. Autophagy is a protective process involving self-cannibalization to maintain cellular energy homeostasis during nutrient deprivation. We developed a mouse model for Lkb1-deficient lung cancer with conditional deletion of essential autophagy gene Atg7 to test whether autophagy compensates for LKB1 loss for tumor cells to survive energy crises. We found that autophagy ablation was synthetically lethal during Lkb1-deficient lung tumorigenesis in both tumor initiation and tumor growth. We further found that autophagy deficiency causes defective intracellular recycling, which limits amino acids to support mitochondrial energy production in starved cancer cells and causes autophagy-deficient cells to be more dependent on fatty acid oxidation (FAO) for energy production, leading to reduced lipid reserve and energy crisis. Our findings strongly suggest that autophagy inhibition could be a strategy for treating LKB1-deficient lung tumors.

PMID: 30692209 [PubMed - indexed for MEDLINE]

Reply to Correspondence by Calugaru and Calugaru to the Article Entitled "Ischemic retinal vein occlusion: characterizing the more severe spectrum of retinal vein occlusion" by Khayat et al.

Surv Ophthalmol. 2019 Jul - Aug;64(4):593-594

Authors: Khayat M, Williams M, Lois N

PMID: 30682402 [PubMed - indexed for MEDLINE]

The Ability of Magnetic Resonance Black Blood Vessel Wall Imaging to Evaluate Blunt Cerebrovascular Injury Following Acute Trauma.

J Neuroradiol. 2019 Jan 21;:

Authors: Vranic JE, Huynh TJ, Fata P, Barber J, Bonow RH, Levitt MR, Temkin N, Morton R, Kelly C, Shibata DK, Mossa-Basha M

Abstract
BACKGROUND AND PURPOSE: Blunt cerebrovascular injury (BCVI) is associated with a significant risk of ischemic stroke when left untreated. Cross-sectional imaging is vital to early BCVI diagnosis and treatment; however, conventional luminal vessel imaging is limited in its ability to evaluate for vessel wall pathology. The purpose of this study is to evaluate the ability of vessel wall MRI (VWI) to detect and evaluate BCVI in acutely injured trauma patients relative to neck CTA.
MATERIALS AND METHODS: Trauma patients with suspected BCVI on initial neck CTA were prospectively recruited for VWI evaluation. Two neuroradiologists blinded to patient clinical history and CTA findings evaluated each artery independently on VWI and noted the presence and grade of BCVI. These results were subsequently compared to neck CTA findings relative to expert clinical consensus review. Interrater reliability of VWI for detecting BCVI was evaluated using a weighted Cohen k -statistic.
RESULTS: Ten trauma patients (40 cervical arteries) were prospectively evaluated using both CTA and VWI. Out of 18 vascular lesions identified as suspicious for BCVI on CTA, 6 lesions were determined to represent true BCVI by expert consensus review. There was almost perfect agreement between VWI and expert consensus regarding the presence and grade of BCVI (k = 0.82). This agreement increased when considering only low grade BCVI. There was only fair agreement between CTA and expert clinical consensus (k = 0.36). This agreement decreased when considering only low grade BCVI.
CONCLUSIONS: VWI can potentially accurately identify and evaluate BCVI in acutely injured trauma patients with excellent interrater reliability.

PMID: 30677426 [PubMed - as supplied by publisher]

Dilute bleach baths used for treatment of atopic dermatitis are not antimicrobial in vitro.

J Allergy Clin Immunol. 2019 05;143(5):1946-1948

Authors: Sawada Y, Tong Y, Barangi M, Hata T, Williams MR, Nakatsuji T, Gallo RL

PMID: 30677478 [PubMed - indexed for MEDLINE]

Emerging neural specialization of the ventral occipitotemporal cortex to characters through phonological association learning in preschool children.

Neuroimage. 2019 04 01;189:813-831

Authors: Pleisch G, Karipidis II, Brauchli C, Röthlisberger M, Hofstetter C, Stämpfli P, Walitza S, Brem S

Abstract
The ventral occipitotemporal (vOT) cortex serves as a core region for visual processing, and specific areas of this region show preferential activation for various visual categories such as faces and print. The emergence of such functional specialization in the human cortex represents a pivotal developmental process, which provides a basis for targeted and efficient information processing. For example, functional specialization to print in the left vOT is an important prerequisite for fluent reading. However, it remains unclear, which processes initiate the preferential cortical activations to characters arising in the vOT during child development. Using a multimodal neuroimaging approach with preschool children at familial risk for developmental dyslexia, we demonstrate how varying levels of expertise modulate the neural response to single characters, which represent the building blocks of print units. The level of expertise to characters was manipulated firstly through brief training of false-font speech-sound associations and secondly by comparing characters for which children differed in their level of familiarity and expertise accumulated through abundant exposure in their everyday environment. Neural correlates of character processing were tracked with simultaneous high-density electroencephalography and functional magnetic resonance imaging in a target detection task. We found training performance and expertise-dependent modulation of the visual event-related potential around 220 ms (N1) and the corresponding vOT activation. Additionally, trained false-font characters revealed stronger functional connectivity between the left fusiform gyrus (FFG) seed and left superior parietal/lateral occipital cortex regions with higher training performance. In sum, our results demonstrate that learning artificial-character speech-sound associations enhances activation to trained characters in the vOT and that the magnitude of this activation and the functional connectivity of the left FFG to the parieto-occipital cortex depends on learning performance. This pattern of results suggests emerging development of the reading network after brief training that parallels network specialization during reading acquisition.

PMID: 30677503 [PubMed - indexed for MEDLINE]

Common variants of T-cells contribute differently to phenotypic variation in sarcoidosis.

Sci Rep. 2017 07 17;7(1):5623

Authors: Rivera NV, Hagemann-Jensen M, Ferreira MAR, Kullberg S, Eklund A, Martin NG, Padyukov L, Grunewald J

Abstract
The involvement of the immune system, particularly the role of T-cells, in sarcoidosis is unclear. The existence of higher CD4+ T-cells and increased CD4/CD8 ratio may indicate a pathogenic role of T-cells in the disease. In this study, we quantified the contribution of T-cells associated variants and of CD4/CD8 ratio in sarcoidosis phenotypes, Löfgren's syndrome (LS) and non- Löfgren's syndrome (non-LS). We employed a polygenic-based approach using genome-wide association studies results on relative levels of T-cells in healthy individuals to measure the genetic contribution of T-cells in sarcoidosis entities. Results revealed that the genetic architecture of LS is highly influenced by genetic variants associated with CD8+ T-cells and CD4/CD8 ratio, explaining up to 7.94% and 6.49% of LS variation, respectively; whereas, the genetic architecture of non-LS is minimally influenced by T-cells, explaining a phenotypic variation of <1%. Moreover, pleiotropy assessment between T-cells and LS/non-LS associated-variants led to the discovery of highly scored pathway maps that shared common factors related to antigen presentation and T-cell regulatory mechanisms. Differences in significant polygenic scores, presence of pleiotropy, and distinct genetic factors provide further insights on how genetic variants and genes associated with relative levels of T-cell subtypes contribute differently to sarcoidosis phenotypes.

PMID: 28717140 [PubMed - indexed for MEDLINE]

A New Active Contours Approach for Finger Extensor Tendon Segmentation in Ultrasound Images Using Prior Knowledge and Phase Symmetry.

IEEE J Biomed Health Inform. 2018 07;22(4):1261-1268

Authors: Martins N, Sultan S, Veiga D, Ferreira M, Teixeira F, Coimbra M, Martins N, Sultan S, Veiga D, Ferreira M, Teixeira F, Coimbra M

Abstract
This work proposes a new approach for the segmentation of the extensor tendon in ultrasound images of the second metacarpophalangeal joint (MCPJ). The MCPJ is known to be frequently involved in early stages of rheumatic diseases like rheumatoid arthritis. The early detection and follow up of these diseases is important to start and adapt the treatments properly and, in that way, preventing irreversible damage of the joints. This work relies on an active contours framework, preceded by a phase symmetry preprocessing and with prior knowledge energies, to automatically identify the extensor tendon. Active contours methods are widely used in ultrasound images because of their robustness to speckle noise and ability to join unconnected smaller regions into a coherent shape. The tendon is formulated as a line so open ended active contours were used. Phase symmetry highlights the tendon, by setting a proper scale range and angle span. The distance between structures and the tendon slope were also included to enforce the model based on anatomical characteristics. And finally, the concavity measures were used because, given the anatomy of the finger, we know that the tendon line should have less than two concavities. To solve the active contours energy minimization a genetic algorithm approach was used. Several energy metric configurations were compared using the modified Hausdorff distance and results showed that this segmentation is not only possible, but exhibits errors smaller than 0.5 mm with a confidence of 95% with the phase symmetry preprocessing and energies based on the line neighborhood, area ratio, slope, and concavity measurements.

PMID: 28693000 [PubMed - indexed for MEDLINE]

Leading by Example: Web-Based Sexual Health Influencers Among Men Who Have Sex With Men Have Higher HIV and Syphilis Testing Rates in China.

J Med Internet Res. 2019 01 21;21(1):e10171

Authors: Wu D, Tang W, Lu H, Zhang TP, Cao B, Ong JJ, Lee A, Liu C, Huang W, Fu R, Li K, Pan SW, Zhang Y, Fu H, Wei C, Tucker JD

Abstract
BACKGROUND: The spread of healthy behaviors through social networks may be accelerated by influential individuals. Previous studies have used lay health influencers to prevent sexually transmitted infections (STIs) among internet-using men who have sex with men (MSM). However, there is a lack of understanding of the characteristics of this key subset of MSM.
OBJECTIVE: This study aimed to examine sociodemographic characteristics, HIV and syphilis testing, and sexual behaviors of Web-based MSM sexual health influencers (SHIs) in China, defined as individuals with relatively stronger influence on spreading HIV and STI information online.
METHODS: A Web-based survey of MSM was conducted in August 2017 as a final follow-up of a randomized controlled trial promoting HIV testing in 8 Chinese cities. Men were recruited through a gay social networking mobile phone app and were included if they were born biologically male, aged 16 years and above, ever had sex with another man, and HIV negative or with unknown HIV status. Information regarding sociodemographic characteristics, sexual behaviors, and HIV and syphilis testing was obtained. We assessed men's Web-based sexual health influence using a standardized 6-item opinion leadership scale focused on HIV and STI information. Influencers were defined as those whose mean score ranked within the top 13% (a higher score means greater influence). We used multivariable linear and logistic regression models to measure Web-based sexual health influence's association with HIV and syphilis testing, controlling for intervention trial effects, age, education, income, and marital status.
RESULTS: Overall, 1031 men completed the survey. Most men were younger than 30 years (819/1031, 79.43%) and had at least college education (667/1031, 64.69%). Influencers were more likely to get tested for HIV (73/132, 55.3% vs 337/899, 37.5%; P<.001) and syphilis (35/132, 26.5% vs 137/899, 15.2%; P=.001) in the last 3 months compared with noninfluencers. There were no significant differences in condomless sex with male partners (26/132, 19.7% vs 203/899, 22.6%; P=.46), mean number of male sex partners (1.32 vs 1.11; P=.16) in the last 3 months, and mainly meeting male sex partners online in the last 12 months (97/132, 73.5% vs 669/899, 74.4%; P=.82) between influencers and noninfluencers. Regression analyses showed that influencers had higher odds of HIV testing (adjusted odds ratio, AOR 2.16, 95% CI 1.48-3.17) and syphilis testing (AOR 1.99, 95% CI 1.28-3.10) in the last 3 months.
CONCLUSIONS: We identified Web-based SHIs who might be more likely to help promote healthy HIV and syphilis testing behaviors through MSM populations. Leveraging existing influencers may help improve HIV and syphilis testing among their networks.

PMID: 30664490 [PubMed - indexed for MEDLINE]

Metal bashing: iron deficiency and manganese overexposure impact on peripheral nerves.

J Toxicol Environ Health A. 2019;82(2):99-112

Authors: Amos-Kroohs RM, Usach V, Piñero G, Vorhees CV, Martinez Vivot R, Soto PA, Williams MT, Setton-Avruj P

Abstract
Iron (Fe) deficiency (FeD) and manganese (Mn) overexposure (MnOE) may result in several neurological alterations in the nervous system. Iron deficiency produces unique neurological deficits due to its elemental role in central nervous system (CNS) development and myelination, which might persist after normalization of Fe in the diet. Conversely, MnOE is associated with diverse neurocognitive deficits. Despite these well-known neurotoxic effects on the CNS, the influence of FeD and MnOE on the peripheral nervous system (PNS) remains poorly understood. The aim of the present investigation was to examine the effects of developmental FeD and MnOE or their combination on the sciatic nerve of young and adult rats. The parameters measured included divalent metal transporter 1 (DMT1), transferrin receptor (TfR), myelin basic protein (MBP) and peripheral myelin protein 22 (PMP22) expression, as well as Fe levels in the nerve. Our results showed that FeD produced a significant reduction in MBP and PMP22 content at P29, which persisted at P60 after Fe-sufficient diet replenishment regardless of Mn exposure levels. At P60 MnOE significantly increased sciatic nerve Fe content and DMT1 expression. However, the combination of FeD and MnOE produced no marked motor skill impairment. Evidence indicates that FeD appears to hinder developmental peripheral myelination, while MnOE may directly alter Fe homeostasis. Further studies are required to elucidate the interplay between these pathological conditions.

PMID: 30652531 [PubMed - indexed for MEDLINE]