709 results
Levofloxacin prophylaxis for pediatric leukemia patients: monitoring of outcomes for sustained benefit and consequences
- Andrea L. Davis, Alexandra M. Stevens, Julienne Brackett, Lucila Marquez, Catherine E. Foster, Adriana Sarmiento Clemente, Hannah E. Sauer, Grant T. Stimes, Judith R. Campbell
-
- Journal:
- Antimicrobial Stewardship & Healthcare Epidemiology / Volume 4 / Issue 1 / 2024
- Published online by Cambridge University Press:
- 22 May 2024, e90
-
- Article
-
- You have access Access
- Open access
- HTML
- Export citation
-
Levofloxacin prophylaxis reduces bloodstream infections in neutropenic patients with acute myeloid leukemia or relapsed acute lymphoblastic leukemia. A retrospective, longitudinal cohort study compares incidence of bacteremia, multidrug-resistant organisms (MDRO), and Clostridioides difficile (CDI) between time periods of levofloxacin prophylaxis implementation. Benefits were sustained without increasing MDRO or CDI.
Comparisons between dual-energy X-ray absorptiometry and bioimpedance devices for appendicular lean mass and muscle quality in Hispanic adults
- Bassel Nassar, Grant M. Tinsley, Kyung-Shin Park, Stefan A. Czerwinski, Brett S. Nickerson
-
- Journal:
- British Journal of Nutrition , First View
- Published online by Cambridge University Press:
- 15 April 2024, pp. 1-8
-
- Article
-
- You have access Access
- Open access
- HTML
- Export citation
-
The purpose of this study was to compare single- and multi-frequency bioimpedance (BIA) devices against dual-energy X-ray absorptiometry (DXA) for appendicular lean mass (ALM) and muscle quality index (MQI) metrics in Hispanic adults. One hundred thirty-one Hispanic adults (18–55 years) participated in this study. ALM was measured with single-frequency bioimpedance analysis (SFBIA), multi-frequency bioimpedance analysis (MFBIA) and DXA. ALMTOTAL (left arm + right arm + left leg + right leg) and ALMARMS (left arm + right arm) were computed for all three devices. Handgrip strength (HGS) was measured using a dynamometer. The average HGS was used for all MQI models (highest left hand + highest right hand)/2. MQIARMS was defined as the ratio between HGS and ALMARMS. MQITOTAL was established as the ratio between HGS and ALMTOTAL. SFBIA and MFBIA had strong correlations with DXA for all ALM and MQI metrics (Lin’s concordance correlation coefficient values ranged from 0·86 (MQIMFBIA-ARMS) to 0·97 (Arms LMSFBIA); all P < 0·001). Equivalence testing varied between methods (e.g. SFBIA v. DXA) when examining the different metrics (i.e. ALMTOTAL, ALMARMS, MQITOTAL and MQIARMS). MQIARMS was the only metric that did not differ from the line of identity and had no proportional bias when comparing all the devices against each other. The current study findings demonstrate good overall agreement between SFBIA, MFBIA and DXA for ALMTOTAL and ALMARMS in a Hispanic population. However, SFBIA and MFBIA have better agreement with DXA when used to compute MQIARMS than MQITOTAL.
466 Development of Machine Learning Algorithms to Predict Symptomatic VTE at Time of Admission and Time of Discharge after Severe Traumatic Injury
- Part of
- Sergio M Navarro, Riley Thompson, Taleen MacArthur, Grant Spears, Kent Bailey, Joe Immermann, Matthew Auton, Jing-Fei Dong, Rosemary Kozar, Myung Park
-
- Journal:
- Journal of Clinical and Translational Science / Volume 8 / Issue s1 / April 2024
- Published online by Cambridge University Press:
- 03 April 2024, pp. 136-137
-
- Article
-
- You have access Access
- Open access
- Export citation
-
OBJECTIVES/GOALS: Clinical indicators predictive of venous thromboembolism (VTE) in trauma patients at multiple time points are not well outlined, particularly at time of discharge. We aimed to describe and predict inpatient and post-discharge risk factors of VTE after trauma using a multi-variate regression model and best of class machine learning (ML) models. METHODS/STUDY POPULATION: In a prospective, case-cohort study, all trauma patients (pts) who arrived as level 1 or 2 trauma activations, from June 2018 to February 2020 were considered for study inclusion. A subset of pts who developed incident, first time, VTE and those who did not develop VTE within 90 days of discharge were identified. VTE were confirmed either by imaging or at autopsy during inpatient stay or post-discharge. Outcomes were defined as the development of symptomatic VTE (DVT and/or PE) within 90 days of discharge.A multi-variate Cox regression model and a best in class of a set of 5 different ML models (support-vector machine, random-forest, naives Bayes, logistic regression, neural network]) were used to predict VTE using models applied a) at 24 hours of injury date or b) on day of patient discharge. RESULTS/ANTICIPATED RESULTS: Among 393 trauma pts (ISS=12.0, hospital LOS=4.0 days, age=48 years, 71% male, 96% with blunt mechanism, mortality 2.8%), 36 developed inpatient VTE and 36 developed VTE after discharge. In a weighted, multivariate Cox model, any type of surgery by day 1, increased age per 10 years, and BMI per 5 points were predictors of overall symptomatic VTE (C-stat 0.738). Prophylactic IVC filter placement (4.40), increased patient age per 10 years, and BMI per 5 points were predictors of post-discharge symptomatic VTE (C-stat= 0.698). A neural network ML model predicted VTE by day 1 with accuracy and AUC of 0.82 and 0.76, with performance exceeding those of a Cox model. A naīve Bayesian ML model predicted VTE at discharge, with accuracy and AUC of 0.81 and 0.77 at time of discharge, with performance exceeding those of a Cox model. DISCUSSION/SIGNIFICANCE: The rate of inpatient and post-discharge VTEs remain high. Limitations: single institution study, limited number of patients, internal validation only, with the use of limited number of ML models. We developed and internally validated a ML based tool.Future work will focus on external validation and expansion of ML techniques.
Head and Neck Cancer: United Kingdom National Multidisciplinary Guidelines, Sixth Edition
- Jarrod J Homer, Stuart C Winter, Elizabeth C Abbey, Hiba Aga, Reshma Agrawal, Derfel ap Dafydd, Takhar Arunjit, Patrick Axon, Eleanor Aynsley, Izhar N Bagwan, Arun Batra, Donna Begg, Jonathan M Bernstein, Guy Betts, Colin Bicknell, Brian Bisase, Grainne C Brady, Peter Brennan, Aina Brunet, Val Bryant, Linda Cantwell, Ashish Chandra, Preetha Chengot, Melvin L K Chua, Peter Clarke, Gemma Clunie, Margaret Coffey, Clare Conlon, David I Conway, Florence Cook, Matthew R Cooper, Declan Costello, Ben Cosway, Neil J A Cozens, Grant Creaney, Daljit K Gahir, Stephen Damato, Joe Davies, Katharine S Davies, Alina D Dragan, Yong Du, Mark R D Edmond, Stefano Fedele, Harriet Finze, Jason C Fleming, Bernadette H Foran, Beth Fordham, Mohammed M A S Foridi, Lesley Freeman, Katherine E Frew, Pallavi Gaitonde, Victoria Gallyer, Fraser W Gibb, Sinclair M Gore, Mark Gormley, Roganie Govender, J Greedy, Teresa Guerrero Urbano, Dorothy Gujral, David W Hamilton, John C Hardman, Kevin Harrington, Samantha Holmes, Jarrod J Homer, Deborah Howland, Gerald Humphris, Keith D Hunter, Kate Ingarfield, Richard Irving, Kristina Isand, Yatin Jain, Sachin Jauhar, Sarra Jawad, Glyndwr W Jenkins, Anastasios Kanatas, Stephen Keohane, Cyrus J Kerawala, William Keys, Emma V King, Anthony Kong, Fiona Lalloo, Kirsten Laws, Samuel C Leong, Shane Lester, Miles Levy, Ken Lingley, Gitta Madani, Navin Mani, Paolo L Matteucci, Catriona R Mayland, James McCaul, Lorna K McCaul, Pádraig McDonnell, Andrew McPartlin, Valeria Mercadante, Zoe Merchant, Radu Mihai, Mufaddal T Moonim, John Moore, Paul Nankivell, Sonali Natu, A Nelson, Pablo Nenclares, Kate Newbold, Carrie Newland, Ailsa J Nicol, Iain J Nixon, Rupert Obholzer, James T O'Hara, S Orr, Vinidh Paleri, James Palmer, Rachel S Parry, Claire Paterson, Gillian Patterson, Joanne M Patterson, Miranda Payne, L Pearson, David N Poller, Jonathan Pollock, Stephen Ross Porter, Matthew Potter, Robin J D Prestwich, Ruth Price, Mani Ragbir, Meena S Ranka, Max Robinson, Justin W G Roe, Tom Roques, Aleix Rovira, Sajid Sainuddin, I J Salmon, Ann Sandison, Andy Scarsbrook, Andrew G Schache, A Scott, Diane Sellstrom, Cherith J Semple, Jagrit Shah, Praveen Sharma, Richard J Shaw, Somiah Siddiq, Priyamal Silva, Ricard Simo, Rabin P Singh, Maria Smith, Rebekah Smith, Toby Oliver Smith, Sanjai Sood, Francis W Stafford, Neil Steven, Kay Stewart, Lisa Stoner, Steve Sweeney, Andrew Sykes, Carly L Taylor, Selvam Thavaraj, David J Thomson, Jane Thornton, Neil S Tolley, Nancy Turnbull, Sriram Vaidyanathan, Leandros Vassiliou, John Waas, Kelly Wade-McBane, Donna Wakefield, Amy Ward, Laura Warner, Laura-Jayne Watson, H Watts, Christina Wilson, Stuart C Winter, Winson Wong, Chui-Yan Yip, Kent Yip
-
- Journal:
- The Journal of Laryngology & Otology / Volume 138 / Issue S1 / April 2024
- Published online by Cambridge University Press:
- 14 March 2024, pp. S1-S224
- Print publication:
- April 2024
-
- Article
-
- You have access Access
- Open access
- HTML
- Export citation
TH-stopping in Philadelphia Puerto Rican English
- Abigail E. Patchell, Grant M. Berry
-
- Journal:
- Language Variation and Change / Volume 36 / Issue 1 / March 2024
- Published online by Cambridge University Press:
- 23 February 2024, pp. 73-93
- Print publication:
- March 2024
-
- Article
- Export citation
-
Analyzing data from the Puerto Rican English in Philadelphia (PREP) corpus, we investigate participation in TH-stopping, a socially stigmatized yet stable variable documented in Philadelphia. While previous studies have been impressionistic and have considered voiced and voiceless tokens to pattern together, this work validates novel, acoustically based stopping indices: mean harmonics-to-noise ratio for voiced tokens and skewness for voiceless tokens. We apply these indices to the corpus data and analyze stopping under a Bayesian framework, and we compare results from a model built from impressionistic coding of a subset of the same data. We find convergent evidence that TH-stopping is a stable variable in the Puerto Rican English data as well. Findings are compared with those of existing studies, noting future directions for research on the variable and underscoring the importance of establishing demographically representative baselines for linguistic research in diverse urban centers.
Stepping on the brakes of the DeLorean: Considerations before implementing universal masking
- Jocelyn A. Srigley, Martha Fulford, Karim Ali, Jennifer M. Grant
-
- Journal:
- Infection Control & Hospital Epidemiology / Volume 45 / Issue 5 / May 2024
- Published online by Cambridge University Press:
- 04 January 2024, p. 690
- Print publication:
- May 2024
-
- Article
-
- You have access Access
- HTML
- Export citation
3 Quick-Reference Criteria for Identifying Clinically Significant Multivariate Change in Older Adult Cognition: A NACC Study
- Amanda M. Wisinger, Hillary F. Abel, Jeremy G. Grant, Glenn E. Smith
-
- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 881-882
-
- Article
-
- You have access Access
- Export citation
-
Objective:
Accurately interpreting cognitive change is an essential aspect of clinical care for older adults. Several approaches to identifying 'true’ cognitive change in a single cognitive measure are available (e.g., reliable change methods, regression-based norms); however, neuropsychologists in clinical settings often rely on simple score differences rather than advanced statistics, especially since multiple scores compose a typical battery. This study sought to establish quick-reference normative criteria to help neuropsychologists identify how frequently significant change occurs across multiple measures in cognitively normal older adults.
Participants and Methods:Data were obtained from the National Alzheimer’s Coordinating Center (NACC). Participants were 845 older adults who were classified as cognitively normal at baseline and at 24-month follow-up. In NACC, these clinical classifications are made separately from the assessment of cognitive performance, including cognitive change. The sample was 34.9% female, 83.5% White, 13.1% Black 2.3% Asian, and 1.1% other race with a mean age of 70.7 years (SD=10.2). Of the sample, 95.5% identified as non-Hispanic. Mean education was 16.1 years (SD=2.8). The cognitive battery entailed: Craft Story Immediate and Delayed Recall, Benson Copy and Delayed Recall, Number Span (Forward & Backward), Category Fluency (Animals & Vegetables), Trails A&B, Multilingual Naming Test, and Verbal Fluency (F&L). Change scores between baseline performance and follow-up were calculated for each measure. The natural distribution of change scores was examined for each measure and cut points representing the 5th and 10th percentile were applied to each distribution to classify participants who exhibited substantial declines in performance on each measure. We then examined the multivariate frequency of statistically rare change scores for each individual.
Results:As expected in a normal sample, overall cognitive performance was generally stable between baseline and 24-month follow-up. Across cognitive measures, 81.9% of participants had at least one change score fall below the 10th percentile in the distribution of change scores, and 55.7% had at least one score below the 5th percentile, 49.3% of participants had two or more change scores that fell below the 10th percentile and 21.1% with two or more below the 5th percentile. There were 26.7% participants that had three or more change scores below the 10th percentile, and 6.4% of participants had three change scores below the 5th percentile.
Conclusions:Among cognitively normal older adults assessed twice at a 24-month interval with a battery of 13 measures, it was not uncommon for an individual to have at least one score fall below the 10th percentile (82% of the sample) or even the 5th percentile (56%) in the natural distribution of change scores. There were 27% participants that had three or more declines in test performance below the 10th percentile; in comparison, only 6% of the sample had three or more change scores at the 5th percentile. This suggests that individuals who exhibit more multivariate changes in performance than these standards are likely experiencing an abnormal rate of cognitive decline. Our findings provide a preliminary quick-reference approach to identifying clinically significant cognitive change. Future studies will explore additional batteries and examine multivariate frequencies of change in clinical populations.
29 Quick-Reference Criteria for Identifying Clinically Significant Multivariate Change in Older Adult Cognition: An ADNI Study
- Jeremy G Grant, Amanda M Wisinger, Glenn E Smith
-
- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 342-343
-
- Article
-
- You have access Access
- Export citation
-
Objective:
Accurately interpreting change in cognitive functioning is an essential aspect of clinical care for older adults. Several approaches to identifying ‘true’ cognitive change in a single cognitive measure are available (e.g., reliable change methods, regression-based norms); however, neuropsychologists in clinical settings often rely on simple score differences rather than advanced analytical procedures especially since they examine multiple test performances. This study sought to establish quick-reference normative criteria to help neuropsychologists identify how frequently significant change occurs across multiple cognitive measures in cognitively normal older adults.
Participants and Methods:Data were obtained from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Participants were 401 older adults who were classified as cognitively normal at baseline and at 24-month follow-up. In ADNI, these clinical classifications are made separately from the assessment of cognitive performance, including cognitive change. The sample was 50.1% female, 93.5% non-Hispanic White, 4.0% non-Hispanic Black, 1.5% Asian American, and 1.0% other race/ethnicity, with a mean age of 76.0 years (SD = 4.9). Mean education was 16.4 years (SD = 2.7). The cognitive battery included: Boston Naming Test, Category Fluency Test, Trails A & B, Clock Drawing Test, and Auditory Verbal Learning Test, Trial 1-5 Total and Delayed Recall. Change scores between baseline performance and 24-month follow-up were calculated for each measure. The natural distribution of change scores was examined for each measure and cut points representing the 5th and 10th percentile were applied to each distribution to classify participants who exhibited substantial declines in performance on a given measure. We then examined the multivariate frequency of statistically rare change scores for each individual.
Results:As expected in a normal sample, overall cognitive performance was generally stable between baseline and 24-month followup. Across cognitive measures, 43.6% of participants had at least one change score fall below the 10th percentile in the distribution of change scores, and 21.9% had at least one score below the 5th percentile. 13.0% of participants had two or more change scores that fell below the 10th percentile, in comparison to 4.5% with two or more below the 5th percentile. 3.2% of participants had three or more change scores below the 10th percentile, versus 0.5% of participants who had three change scores below the 5th percentile.
Conclusions:Among cognitively normal older adults assessed twice at a 24-month interval with a battery of seven measures, it was not uncommon for an individual to have at least one score fall below the 10th percentile (43% of the sample) or even the 5th percentile (21%) in the natural distribution of change scores. However, only 3.2% of normals had more than two declines in test performance below the 10th percentile, and less than 1% of the sample at more than one change score at the 5th percentile. This suggests that individuals who exhibit more multivariate changes in performance than these standards are likely experiencing an abnormal rate of cognitive decline. Our findings provide a preliminary quick-reference approach to identifying clinically significant cognitive change. Future studies will explore additional batteries and examine multivariate frequencies of change in clinical populations.
31 Item and Associative Visual Memory in Presurgical Temporal Lobe Epilepsy Patients
- Jared B Hammond, Robert M Roth, Christi L Trask, Grant G Moncrief
-
- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 30-31
-
- Article
-
- You have access Access
- Export citation
-
Objective:
Patients with temporal lobe epilepsy (TLE) commonly show memory deficits on neuropsychological tests. The BVMT-R is a widely used test of visual learning and memory that involves accurately reproducing an array of figures in the correct special location. The present study examined performance processes of visual memory in presurgical patients with TLE, including item (i.e., accuracy) and associative memory (i.e., location), which have been shown to be dissociable in studies of visual memory in other neurologic populations.
Participants and Methods:Participants included nine patients with left TLE (67% female; 67% left-handed; mean age = 46.15 years, range = 24-55; mean education = 14.8 years, range = 9-18) and six patients with right TLE (17% female; 33% left-handed; mean age = 57.64 years, range = 22-62; mean education = 15.52 years, range 11-18). Mean duration of epilepsy was 19 years. Participants had an average of two failed anti-seizure medications prior to surgery. TLE groups were compared to 22 healthy controls (36% female; 14% left-handed; mean age = 33.68 years, range = 2253; mean education = 17.66 years, range = 1620). All participants completed comprehensive neuropsychological testing at a large Northeastern medical center. The BVMT-R was scored using standard and novel scoring paradigms. All data were retrospectively reviewed from archival datasets.
Results:MANCOVA results indicated a significant multivariate main effect for group membership and standard BVMT-R scoring after controlling for level of education, Wilks’ A = 0.59, F(4, 64) = 4.91, p = .002. The multivariate partial eta squared (np2) of .58 indicated a strong relationship between group membership and both immediate and delayed recall, with the control group performing better overall. The TLE groups did not perform significantly different from each other. A significant multivariate main effect for group and novel BVMT-R scoring was found (also controlling for education), Wilks’ A = 0.42, F(8, 58) = 3.97, p = .001. Overall, the control group demonstrated better item learning with no significant difference between TLE groups observed. Both the control (M = (16.5, SD = 2.04) and left TLE (M = 12.33, SD = 4.03) showed stronger associative learning compared to the right TLE group (M = 10.2, SD = 4.27). For item and location delayed recall, controls (M = 4.82, SD = 1.62) had more accurate recall compared to left TLE (M = 1.56, SD = 2.04) with a trend toward better performance compared to the right TLE patients (M = 2.6, SD = 1.82); the TLE groups performed similarly. No difference was observed for associative delayed recall between the three groups.
Conclusions:Patients with right TLE showed worse associative learning compared to left TLE, while performance was generally comparable to their right TLE counterparts on other novel BVMT-R scoring paradigms. Unsurprisingly, patients with TLE performed worse on BVMT-R using standard scoring procedures, though no lateralizing effect was observed. While these findings suggest that associative visual learning weakness may be characteristic of right TLE, findings should be interpreted cautiously the given small sample size and demographic considerations (i.e., uneven gender distribution, lack of data on ethnicity/race).
Repeated freezing impacts buoyancy and photosynthesis of a rafting kelp species
- Sophie M. Sinclair, Grant A. Duffy, Ceridwen I. Fraser
-
- Journal:
- Antarctic Science / Volume 35 / Issue 6 / December 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 403-406
-
- Article
-
- You have access Access
- Open access
- HTML
- Export citation
-
Antarctica was once considered biologically isolated, surrounded by oceanic barriers (Fraser et al. 2018). However, floating materials such as kelp rafts (Fraser et al. 2018, Avila et al. 2020), wood (Lewis et al. 2005) and plastics (Avila et al. 2020) are now known to cross these barriers and reach Antarctic shores. Such incursions might enable non-native species (either rafting species themselves or associated hitchhikers) to colonize Antarctica as the climate warms (Avila et al. 2020, Fraser et al. 2020), but whether these species will be able to survive and reproduce in the Antarctic is not yet known. Sea ice is a defining characteristic of Antarctic coastlines, and modelled trajectories of kelp rafts (Fraser et al. 2018) cross-referenced against sea-ice observations (Parkinson 2019) suggest that collisions between rafts and seasonal sea ice occur frequently (Fig. 1a); thus, rafts are expected to be entrained in, on or under sea ice and experience multiple freeze-and-thaw cycles on their journeys to Antarctica. In addition, kelp rafts that reach the Antarctic intertidal will experience temperatures well below 0°C if exposed to the air at low tide. Freezing can cause severe disruptive stress to seaweeds, and ice crystals growing in intercellular spaces can damage cell membranes and cause cell lysis (Eggert 2012). Such damage could affect the buoyancy of kelp tissue and decrease rafting ability. Although some non-native kelp rafts recovered from Antarctic shores appeared to still be reproductively viable, with mature gametes observed in reproductive tissue (Fraser et al. 2018), tissue damage caused by freezing could have widespread effects on the health, function and establishment success of a non-native species traversing the Southern Ocean.
32 Prediction of Seizure Outcome with Presurgical IAT, MRI, and PET in Patients with Temporal Lobe Epilepsy Undergoing Surgery
- Grant G Moncrief, Stephen L Aita, Jennifer Lee, Bryce Jacobson, George P Thomas, Robert M Roth, Angeline S Andrew, Krzysztof A Bujarski, Vijay M Thadani, Erik J Kobylarz, Stephen J Guerin, David W Roberts, Barbara C Jobst
-
- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 31-32
-
- Article
-
- You have access Access
- Export citation
-
Objective:
Anterior temporal lobectomy is a common surgical approach for medication-resistant temporal lobe epilepsy (TLE). Prior studies have shown inconsistent findings regarding the utility of presurgical intracarotid sodium amobarbital testing (IAT; also known as Wada test) and neuroimaging in predicting postoperative seizure control. In the present study, we evaluated the predictive utility of IAT, as well as structural magnetic resonance imaging (MRI) and positron emission tomography (PET), on long-term (3-years) seizure outcome following surgery for TLE.
Participants and Methods:Patients consisted of 107 adults (mean age=38.6, SD=12.2; mean education=13.3 years, SD=2.0; female=47.7%; White=100%) with TLE (mean epilepsy duration =23.0 years, SD=15.7; left TLE surgery=50.5%). We examined whether demographic, clinical (side of resection, resection type [selective vs. non-selective], hemisphere of language dominance, epilepsy duration), and presurgical studies (normal vs. abnormal MRI, normal vs. abnormal PET, correctly lateralizing vs. incorrectly lateralizing IAT) were associated with absolute (cross-sectional) seizure outcome (i.e., freedom vs. recurrence) with a series of chi-squared and t-tests. Additionally, we determined whether presurgical evaluations predicted time to seizure recurrence (longitudinal outcome) over a three-year period with univariate Cox regression models, and we compared survival curves with Mantel-Cox (log rank) tests.
Results:Demographic and clinical variables (including type [selective vs. whole lobectomy] and side of resection) were not associated with seizure outcome. No associations were found among the presurgical variables. Presurgical MRI was not associated with cross-sectional (OR=1.5, p=.557, 95% CI=0.4-5.7) or longitudinal (HR=1.2, p=.641, 95% CI=0.4-3.9) seizure outcome. Normal PET scan (OR= 4.8, p=.045, 95% CI=1.0-24.3) and IAT incorrectly lateralizing to seizure focus (OR=3.9, p=.018, 95% CI=1.2-12.9) were associated with higher odds of seizure recurrence. Furthermore, normal PET scan (HR=3.6, p=.028, 95% CI =1.0-13.5) and incorrectly lateralized IAT (HR= 2.8, p=.012, 95% CI=1.2-7.0) were presurgical predictors of earlier seizure recurrence within three years of TLE surgery. Log rank tests indicated that survival functions were significantly different between patients with normal vs. abnormal PET and incorrectly vs. correctly lateralizing IAT such that these had seizure relapse five and seven months earlier on average (respectively).
Conclusions:Presurgical normal PET scan and incorrectly lateralizing IAT were associated with increased risk of post-surgical seizure recurrence and shorter time-to-seizure relapse.
4 Methamphetamine, cannabis, HIV, and their combined effects on neurocognition
- Jeffrey M Rogers, Igor Grant, Maria Cecilia Marcondes, Erin E Morgan, Mariana Cherner, Ronald J Ellis, Scott L Letendre, Robert K Heaton, Jennifer E Iudicello
-
- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 797-798
-
- Article
-
- You have access Access
- Export citation
-
Objective:
Methamphetamine and cannabis are two widely used substances with possibly opposing effects on aspects of central nervous system functioning. Use of these substances is prevalent among people with HIV (PWH), though their combined effects on HIV-associated neurocognitive impairment (NCI) are unknown. Adverse effects of methamphetamine use on cognition are well documented. Cannabis may disturb cognition acutely, though its longer-term effects in PWH are not well understood. Our prior analysis of people without HIV (PWoH) found that cotemporaneous cannabis use was associated with better neurocognitive outcomes among methamphetamine users. The aim of this study was to assess how lifetime cannabis and methamphetamine use disorder relate to neurocognitive outcomes in PWH.
Participants and Methods:HIV-positive participants (n=472) were on average 45.6±11.5 years of age, male (86.4%), White (60.6%), and educated 13.9±2.5 years. Most participants were on ART (81.9%) and virally suppressed (70%). Participants were stratified by lifetime methamphetamine (M-/M+) and cannabis (C-/C+) DSM-IV abuse/dependence disorder into four groups: M-C- (n=187), M-C+ (n=68), M+C-, (n=82) and M+C+ (n=135) and completed a comprehensive neurobehavioral assessment. Demographically corrected T-scores and deficit scores were used for analyses. Group differences in global and domain NC performances (i.e., T-scores) were examined using multiple linear regression, holding constant covariates that were associated with study groups and/or cognition. Specifically, M+ participants displayed higher rates of Hepatitis C infection (p=.004), higher current depressive symptom scores (p<.001), and higher rates of detectable plasma HIV RNA (p=.014). Multiple logistic regression was used to test for group differences in probability of neurocognitive impairment (i.e., deficit scores>0.5), including the same covariates. Pooling data with a sample of HIV-negative participants (n=423), we used generalized linear mixed effect models to examine how neurocognitive performance and impairment profiles varied by methamphetamine and/or cannabis use group, HIV disease characteristics, and their interactions.
Results:Compared to M+C+, M+C- performed worse on measures of executive functions (ß=-3.17), learning (ß=-3.95), memory (ß=-5.58), and working memory (ß=-4.05) and were more likely to be classified as impaired in the learning (OR=2.93), memory (OR=5.24), and working memory (OR=2.48) domains. M-C- performed better than M+C+ on measures of learning (ß=3.46) and memory (ß=5.19), but worse than M-C+ on measures of executive functions (ß=-3.90), learning (ß=-3.32), memory (ß=-3.38), and working memory (ß=-3.38). Generalized linear mixed effect models indicate that detectable plasma HIV RNA (ß=-1.85) and low nadir CD4 T-cell counts (nadir CD4<200; ß=-1.07) were associated with worse neurocognitive performance, and these effects did not differ in size or direction by substance use group.
Conclusions:In PWH, lifetime methamphetamine use disorder and both current and legacy markers of HIV disease severity are associated with worse neurocognitive outcomes. Cannabis use disorder does not appear to exacerbate methamphetamine-related deficits in PWH. Instead, results are consistent with findings from preclinical studies that cannabis use may protect against methamphetamine’s deleterious effects. Profile analysis models showed that participants with a history of cannabis use disorder display better overall neurocognitive performance than comparison (M-C-) participants. Mechanisms underlying a potential protective effect of cannabis may be elucidated by examining the temporal relationship between cannabis and methamphetamine consumption and neurocognitive performance.
3 The Relationship Between Apolipoprotein-E4 Genotype, Memory, and the Medial Temporal Lobe and How These Relationships Vary by Race in Middle-Aged Persons with HIV
- Laura M Campbell, Maulika Kohli, Erin E Sundermann, Christine Fennema-Notestine, Averi Barrett, Cinnamon Bloss, Mark W Bondi, David B Clifford, Ronald J Ellis, Donald Franklin, Benjamin Gelman, Igor Grant, Robert K Heaton, Scott Letendre, Payal B Patel, David J Moore, Susan Morgello, Raeanne C Moore
-
- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 683-684
-
- Article
-
- You have access Access
- Export citation
-
Objective:
Many people with HIV (PWH) are at risk for age-related neurodegenerative disorders such as Alzheimer’s disease (AD). Studies on the association between cognition, neuroimaging outcomes, and the Apolipoprotein E4 (APOE4) genotype, which is associated with greater risk of AD, have yielded mixed results in PWH; however, many of these studies have examined a wide age range of PWH and have not examined APOE by race interactions that are observed in HIV-negative older adults. Thus, we examined how APOE status relates to cognition and medial temporal lobe (MTL) structures (implicated in AD pathogenesis) in mid- to older-aged PWH. In exploratory analyses, we also examined race (African American (AA)/Black and non-Hispanic (NH) White) by APOE status interactions on cognition and MTL structures.
Participants and Methods:The analysis included 88 PWH between the ages of 45 and 68 (mean age=51±5.9 years; 86% male; 51% AA/Black, 38% NH-White, 9% Hispanic/Latinx, 2% other) from the CNS HIV Antiretroviral Therapy Effects Research multi-site study. Participants underwent APOE genotyping, neuropsychological testing, and structural MRI; APOE groups were defined as APOE4+ (at least one APOE4 allele) and APOE4- (no APOE4 alleles). Eighty-nine percent of participants were on antiretroviral therapy, 74% had undetectable plasma HIV RNA (<50 copies/ml), and 25% were APOE4+ (32% AA/Black/15% NH-White). Neuropsychological testing assessed seven domains, and demographically-corrected T-scores were calculated. FreeSurfer 7.1.1 was used to measure MTL structures (hippocampal volume, entorhinal cortex thickness, and parahippocampal thickness) and the effect of scanner was regressed out prior to analyses. Multivariable linear regressions tested the association between APOE status and cognitive and imaging outcomes. Models examining cognition covaried for comorbid conditions and HIV disease characteristics related to global cognition (i.e., AIDS status, lifetime methamphetamine use disorder). Models examining the MTL covaried for age, sex, and
relevant imaging covariates (i.e., intracranial volume or mean cortical thickness).
Results:APOE4+ carriers had worse learning (ß=-0.27, p=.01) and delayed recall (ß=-0.25, p=.02) compared to the APOE4- group, but APOE status was not significantly associated with any other domain (ps>0.24). APOE4+ status was also associated with thinner entorhinal cortex (ß=-0.24, p=.02). APOE status was not significantly associated with hippocampal volume (ß=-0.08, p=0.32) or parahippocampal thickness (ß=-0.18, p=.08). Lastly, race interacted with APOE status such that the negative association between APOE4+ status and cognition was stronger in NH-White PWH as compared to AA/Black PWH in learning, delayed recall, and verbal fluency (ps<0.05). There were no APOE by race interactions for any MTL structures (ps>0.10).
Conclusions:Findings suggest that APOE4 carrier status is associated with worse episodic memory and thinner entorhinal cortex in mid- to older-aged PWH. While APOE4+ groups were small, we found that APOE4 carrier status had a larger association with cognition in NH-White PWH as compared to AA/Black PWH, consistent with studies demonstrating an attenuated effect of APOE4 in older AA/Black HIV-negative older adults. These findings further highlight the importance of recruiting diverse samples and suggest exploring other genetic markers (e.g., ABCA7) that may be more predictive of AD in some races to better understand AD risk in diverse groups of PWH.
4 Assessing Visuospatial Skills in Parkinson’s Disease Using the Identi-Fi
- AnneMarie Teti, Ryan C. Thompson, Grant G. Moncrief, Robert M. Roth
-
- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 690-691
-
- Article
-
- You have access Access
- Export citation
-
Objective:
Patients with Parkinson’s disease (PD) commonly show deficits on tests of visuospatial functioning. The Identi-Fi is a new measure of visual organization and recognition composed of two components. The Visual Recognition (VR) subtest asks persons to identify an object that has been broken its pieces and rearranged, akin to the Hooper Visual Organization Test, but using updated and colorful pictures. The Visual Matching (VM) subtest involves showing the same stimuli, but the examinee must select the correct response from among five choices (1 correct and 4 foils), placing greater demand on visuospatial discrimination. Together, the two subtests comprise the Visual Organization Index (VOI), reflecting overall visual processing and organization ability. The present study examined performance on the Identi-Fi in patients with PD and its association with other aspects of cognition.
Participants and Methods:Participants were 23 patients with PD (95% male; mean age = 69.7 years [SD = 7.8], range = 47-79) and 12 patients with cognitive concerns (CC) who were intact on neuropsychological testing (excluding consideration of Identi-Fi scores; 50% male, mean age = 71.08 [SD = 6.27], range = 60-78) seen for a neuropsychological evaluation at a large Northeastern medical center. As part of a larger battery, patients completed the Identi-Fi, Trail Making Test (TMT), Category Fluency, Test of Premorbid Functioning (TOPF), and Brief Visuospatial Memory Test, Revised (BVMT-R).
Results:The PD group performed significantly worse than the CC group on VR and VM, as well as VOI, of the Identi-Fi (p < .001). Within the PD group, poorer VR, VM, and VOI performance was associated with lower scores on the TOPF (p < .05), BVMT-R learning (p < .05) and delayed recall (p < .05), as well as TMT Parts A and B (p < .05). VR was significantly correlated with Category Fluency (p < .05), while a trend was seen for the association between VOI and Category Fluency (p = .094).
Conclusions:Identi-Fi performance was worse in the PD group than the CC group, which is consistent with prior research indicating that visuospatial processing is often abnormal in patients with PD. Furthermore, findings indicate that poorer performance on the Identi-Fi in the PD group is associated with poorer cognitive functioning in other domains (i.e., visuospatial learning and memory, processing speed, cognitive flexibility, and semantic fluency), as well as lower premorbid intellectual functioning. While these findings suggest that the Identi-Fi is useful in identifying visuospatial dysfunction in PD, findings should be interpreted with caution given the small sample sizes and uneven gender distribution
62 Exploration of Sex Differences in Cannabis Use Patterns, Driving Performance, and Subjective Intoxication Effects
- Kyle F. Mastropietro, Jeffrey M. Rogers, Dafna Paltin, Anya Umlauf, David J. Grelotti, Robert L. Fitzgerald, Igor Grant, Thomas D. Marcotte
-
- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 847-848
-
- Article
-
- You have access Access
- Export citation
-
Objective:
Although some animal research suggests possible sex differences in response to THC exposure (e.g., Cooper & Craft, 2018), there are limited human studies. One study found that among individuals rarely using cannabis, when given similar amounts of oral and vaporized THC females report greater subjective intoxication compared to males (Sholler et al., 2020). However, in a study of daily users, females reported indistinguishable levels of intoxication compared to males after smoking similar amounts (Cooper & Haney, 2014), while males and females using 1–4x/week showed similar levels of intoxication, despite females having lower blood THC and metabolite concentrations (Matheson et al., 2020). It is important to elucidate sex differences in biological indicators of cannabis intoxication given potential driving/workplace implications as states increasingly legalize use. The current study examined if when closely matching males and females on cannabis use variables there are predictable sex differences in residual whole blood THC and metabolite concentrations, and THC/metabolites, subjective appraisals of intoxication, and driving performance following acute cannabis consumption.
Participants and Methods:The current study was part of a randomized clinical trial (Marcotte et al., 2022). Participants smoked ad libitum THC cigarettes and then completed driving simulations, blood draws, and subjective measures of intoxication. The main outcomes were the change in Composite Drive Score (CDS; global measure of driving performance) from baseline, whole blood THC, 11-OH-THC, and THC-COOH levels (ng/mL), and subjective ratings of how “high” participants felt (0 = not at all, 100 = extremely). For this analysis of participants receiving active THC, males were matched to females on 1) estimated THC exposure (g) in the last 6 months (24M, 24F) or 2) whole blood THC concentrations immediately post-smoking (23M, 23F).
Results:When matched on THC exposure in the past 6 months (overall mean of 46 grams; p = .99), there were no sex differences in any cannabinoid/metabolite concentrations at baseline (all p > .83) or after cannabis administration (all p > .72). Nor were there differences in the change in CDS from pre-to-post-smoking (p = .26) or subjective “highness” ratings (p = .53). When matched on whole blood THC concentrations immediately after smoking (mean of 34 ng/mL for both sexes, p = .99), no differences were found in CDS change from pre-to-post smoking (p = .81), THC metabolite concentrations (all p > .25), or subjective “highness” ratings (p = .56). For both analyses, males and females did not differ in BMI (both p > .7).
Conclusions:When male/female cannabis users are well-matched on use history, we find no significant differences in cannabinoid concentrations following a mean of 5 days of abstinence, suggesting that there are no clear biological differences in carryover residual effects. We also find no significant sex differences following ad libitum smoking in driving performance, subjective ratings of “highness,” nor whole blood THC and metabolite concentrations, indicating that there are no biological differences in acute response to THC. This improves upon previous research by closely matching participants over a wider range of use intensity variables, although the small sample size precludes definitive conclusions.
62 Cognitive Functioning and Non-Cognitive Symptoms in Post-Acute COVID-19 Syndrome
- Melissa M Gardner, Ryan C Thompson, Grant G Moncrief, Robert M Roth
-
- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 58-59
-
- Article
-
- You have access Access
- Export citation
-
Objective:
Patients with Post-Acute COVID Syndrome (PACS) are reported to commonly experience a variety of cognitive, physical, and neuropsychiatric symptoms well beyond the acute phase of the illness. Notably, concerns involving mood, fatigue, and physical symptoms (e.g., pain, headaches) following COVID-19 appears to be especially prevalent. It is unclear, however, the extent to which such symptoms are associated with cognitive problems in patients with PACS. In the present study, we examined the prevalence of cognitive impairment in a sample of patients with PACS, as well as the relationship between cognitive functioning and several non-cognitive symptoms.
Participants and Methods:Participants were 38 patients with PACS [71.1% female; mean age = 48.03 years (SD = 11.60) and years of education = 15.26 years (SD = 2.60)] seen for a neuropsychological evaluation at a large Northeastern medical center at least three months from the time of COVID-19 diagnosis (per PCR test). As part of a larger battery, patients completed the Hopkins Verbal Learning Test- Revised (HVLT, learning and delayed recall), Trail Making Test (TMT; time to complete parts A and B), Controlled Oral Word Association Test (COWAT total correct), and Animals (total correct). They also were administered the Chalder Fatigue Scale-11 (CFS-11), Beck Depression Inventory-II (BDI-II), Beck Anxiety Inventory (BAI), and Patient Health Questionnaire (PHQ-15). The percentage of patients with scores in the impaired range (z < -1.5) on cognitive tests was determined. Correlations between cognitive and non-cognitive measures were also examined.
Results:The most frequent impairment was seen for COWAT (21.2%), followed by TMT-A and TMT-B (both 13.9%), then category fluency (9.1%). No patients were impaired on HVLT-R Learning and only one (4%) for HVLT-R Delayed Recall. Overall, the sample endorsed considerable depression, anxiety, fatigue, as well as physical symptoms. Greater fatigue was associated with worse verbal learning, processing speed, cognitive flexibility, and verbal fluency (letter and category). Worse physical symptom severity was related to poorer verbal delayed recall and cognitive flexibility. Greater anxiety was also associated with worse cognitive flexibility, while more severe depression was related to poorer category fluency.
Conclusions:In our sample of patients with PACS, seen for evaluation several months since contracting COVID-19, phonemic fluency was the most common cognitive impairment, though less than a quarter were impaired on any given cognitive test. Importantly, several associations were observed between cognitive test performance and non-cognitive symptoms commonly endorsed by patients with PACS. These findings highlight the importance of assessing multiple factors potentially contributing to cognitive impairment in these patients. Interventions designed to address such symptoms may be helpful in ameliorating cognitive functioning in those with PACS.
90 Self-Rated Executive Dysfunction in Older Adults with Subjective Cognitive Dysfunction and Mild Cognitive Impairment
- Ryan C Thompson, Melissa M Gardner, Grant G Moncrief, Robert M Roth
-
- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 290-291
-
- Article
-
- You have access Access
- Export citation
-
Objective:
Mild cognitive impairment (MCI) is characterized by subjective and objective memory concerns, though additional cognitive concerns are commonly reported, including changes in executive functions (EF). Rabin et al. (2006) showed that a sample of research participants with MCI endorsed problems with their EFs, especially working memory. Similarly, those with subjective cognitive dysfunction (SCD) also reported greater difficulty with aspects of their EF than a healthy comparison sample of older adults (HC). In the present study, we investigated subjective EF in clinical samples of older adults with MCI or SCD, which represents a more naturalistic sample relative to a research sample. Furthermore, we evaluated whether subjective EF varied in these groups depending on whether patients were "young-old" versus "old-old" given prior research indicating objective cognitive differences between these age groups.
Participants and Methods:Participants were 135 older adults (53 MCI, 52 SCD, and 30 HC) matched for age (p = .116) and education (p = .863). Dichotomous categorization of age used the sample median (72 years) as cutoff score with 72 participants in the young-old group (mean age = 65.8 ± 4.7 years) and 63 in the old-old group (mean age = 78.1 ± 3.7 years). Participants completed the Behavior Rating Inventory of Executive Function-Adult (BRIEF-A), assessing executive functions in everyday life over the past month. The BRIEF-A yields an overall score (Global Executive Composite [GEC]) composed of two index scores (Behavioral Regulation Index [BRI] and Metacognition Index [MI]) and nine clinical scales (Inhibit, Shift, Emotional Control, Self-Monitor, Initiate, Working Memory, Plan/Organize, Task Monitor, and Organization of Materials). A diagnosis by age-group multivariate analysis of variance (MANOVA) with post-hoc comparisons for diagnosis using a Tukey HSD correction was conducted using SPSS Version 24.
Results:MCI and SCD groups endorsed worse EF on all three index scores (ps < .005) and all nine clinical scales (ps < .05) relative to the HC group, and the MCI group reported worse initiation relative to the SCD group. Additionally, worse executive functions on all three index scores (ps < .05) and four clinical scales (ps < .05; emotional control, self-monitoring, planning/organization, and task monitoring) were reported by the young-old group relative to the old-old group. No diagnosis by age-group interactions were observed.
Conclusions:Problems with aspects of EF were endorsed by older adults with MCI and SCD compared to HCs across all indices and clinical scales; however, only initiation was reported to be worse in MCI than those with SCD. Additionally, the young-old group endorsed having worse EF than the old-old group across BRIEF-A indices and several more specific aspects of EF, without a moderating effect of diagnosis. These findings highlight the importance of assessing subjective EF in older adults, as they may be early indicators of cognitive change, prior to objective evidence of cognitive decline. Furthermore, results also point to differences in how the young-old and old-old perceive their EF in everyday life.
GWAS of Dizygotic Twinning in an Enlarged Australian Sample of Mothers of DZ Twins
- Scott D. Gordon, David L. Duffy, David C. Whiteman, Catherine M. Olsen, Kerrie McAloney, Jessica M. Adsett, Natalie A. Garden, Simone M. Cross, Susan E. List-Armitage, Joy Brown, Jeffrey J. Beck, Hamdi Mbarek, Sarah E. Medland, Grant W. Montgomery, Nicholas G. Martin
-
- Journal:
- Twin Research and Human Genetics / Volume 26 / Issue 6 / December 2023
- Published online by Cambridge University Press:
- 23 November 2023, pp. 327-338
-
- Article
-
- You have access Access
- Open access
- HTML
- Export citation
-
Female fertility is a complex trait with age-specific changes in spontaneous dizygotic (DZ) twinning and fertility. To elucidate factors regulating female fertility and infertility, we conducted a genome-wide association study (GWAS) on mothers of spontaneous DZ twins (MoDZT) versus controls (3273 cases, 24,009 controls). This is a follow-up study to the Australia/New Zealand (ANZ) component of that previously reported (Mbarek et al., 2016), with a sample size almost twice that of the entire discovery sample meta-analysed in the previous article (and five times the ANZ contribution to that), resulting from newly available additional genotyping and representing a significant increase in power. We compare analyses with and without male controls and show unequivocally that it is better to include male controls who have been screened for recent family history, than to use only female controls. Results from the SNP based GWAS identified four genomewide significant signals, including one novel region, ZFPM1 (Zinc Finger Protein, FOG Family Member 1), on chromosome 16. Previous signals near FSHB (Follicle Stimulating Hormone beta subunit) and SMAD3 (SMAD Family Member 3) were also replicated (Mbarek et al., 2016). We also ran the GWAS with a dominance model that identified a further locus ADRB2 on chr 5. These results have been contributed to the International Twinning Genetics Consortium for inclusion in the next GWAS meta-analysis (Mbarek et al., in press).
Associations of free, bioavailable and total 25-hydroxyvitamin D with neonatal birth anthropometry and calcium homoeostasis in mother–child pairs in a sunny Mediterranean region
- Hana M. A. Fakhoury, Tarek Ziad Arabi, Hani Tamim, Rene F. Chun, William B. Grant, Martin Hewison, Fatme AlAnouti, Stefan Pilz, Cedric Annweiler, Georgios Tzimagiorgis, Costas Haitoglou, Spyridon N. Karras
-
- Journal:
- British Journal of Nutrition / Volume 131 / Issue 5 / 14 March 2024
- Published online by Cambridge University Press:
- 26 October 2023, pp. 801-808
- Print publication:
- 14 March 2024
-
- Article
-
- You have access Access
- Open access
- HTML
- Export citation
-
Sufficient vitamin D status is crucial for successful pregnancy and fetal development. The assessment of 25-hydroxyvitamin D (25(OH)D) concentrations is commonly used to evaluate vitamin D status. Our objective was to examine the interrelated biodynamics of maternal and neonatal total, free and bioavailable 25(OH)D in maternal–neonatal dyads at birth and their associations with homeostasis and neonatal birth anthropometry. We analysed a cohort of seventy full-term mother–child pairs. We found positive associations between all neonatal measures of vitamin D status. Maternal forms exhibited a similar pattern of association, except for the bioavailable maternal form. In multivariate analysis, both total and free maternal 25(OH)D concentrations were correlated with all neonatal forms (neonatal total 25(OH)D: 1·29 (95 % CI, 1·12, 1·46) for maternal total 25(OH)D, 10·89 (8·16, 13·63) for maternal free 25(OH)D), (neonatal free 25(OH)D: 0·15 for maternal total 25(OH)D, 1·28 (95 % CI, 0·89, 1·68) for maternal free 25(OH)D) and (0·13 (95 % CI, 0·10, 0·16), 1·06 (95 % CI, 0·68, 1·43) for maternal free 25(OH)D), respectively, with the exclusion of the bioavailable maternal form. We observed no significant interactions within or between groups regarding maternal and neonatal vitamin D parameters and maternal calcium and parathyroid hormone concentrations, and neonatal birth anthropometry. Our study indicates that bioavailable maternal and neonatal 25(OH)D have no significant effects on vitamin D equilibrium, Ca homeostasis and neonatal anthropometry at birth. However, we observed an interaction between maternal and neonatal total and free 25(OH)D concentrations at the maternal–neonatal interface, with no associations observed with other calciotropic or anthropometric outcomes.
RADIOCARBON ANALYSIS OF SOIL MICROBIAL BIOMASS VIA DIRECT CHLOROFORM EXTRACTION
- Kari M Finstad, Erin E Nuccio, Katherine E Grant, Taylor A B Broek, Jennifer Pett-Ridge, Karis J McFarlane
-
- Journal:
- Radiocarbon , First View
- Published online by Cambridge University Press:
- 02 October 2023, pp. 1-9
-
- Article
-
- You have access Access
- Open access
- HTML
- Export citation
-
Microbial processing of soil organic matter is a significant driver of C cycling, yet we lack an understanding of what shapes the turnover of this large terrestrial pool. In part, this is due to limited options for accurately identifying the source of C assimilated by microbial communities. Laboratory incubations are the most common method for this; however, they can introduce artifacts due to sample disruption and processing and can take months to produce sufficient CO2 for analysis. We present a biomass extraction method which allows for the direct 14C analysis of microbial biomolecules and compare the results to laboratory incubations. In the upper 50 cm soil depths, the Δ14C from incubations was indistinguishable from that of extracted microbial biomass. Below 50 cm, the Δ14C of the biomass was more depleted than that of the incubations, either due to the stimulation of labile C decomposition in the incubations, the inclusion of biomolecules from non-living cells in the biomass extractions, or differences in C used for assimilation versus respiration. Our results suggest that measurement of Δ14C of microbial biomass extracts can be a useful alternative to soil incubations.