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Nevin Manimala Statistics

Latent Semantic Structure of the WMS-III Verbal Paired-Associates

Arch Clin Neuropsychol. 2021 Dec 20:acab093. doi: 10.1093/arclin/acab093. Online ahead of print.

ABSTRACT

OBJECTIVE: To investigate the factor structure of the verbal paired-associates (VPA) subtest in the WMS-III using a theoretically driven model of semantic processing previously found to be well-fitting for the WMS-IV version of the test.

METHOD: Archival data were used from 267 heterogeneous neurosciences patients and 223 seizure disorder patients who completed the WMS-III as part of a standard neuropsychological evaluation. Confirmatory factor analysis was used to test theoretically driven models for VPA based on principles of semantic processing. Four nested models of different complexities were examined and compared for goodness-of-fit using chi-squared difference testing. Measurement invariance testing was conducted across heterogeneous neuroscience and seizure disorder samples to test generality of the factor model.

RESULTS: After removing items with limited variability (very easy or very hard; 12 of 40 items), a four-factor model was found to be best-fitting in the present patient samples. The four factors were “recreational”, “functional”, “material”, and “symbolic”, each representing semantic knowledge associated with the function of the target word referent. This model subsequently met the criteria for the strict measurement invariance, showing good overall fit when factor loadings, thresholds, and residuals were held to equality across samples.

CONCLUSIONS: The results of this study provide further evidence that “arbitrary” associations between word pairs in VPA items have an underlying semantic structure, challenging the idea that unrelated hard-pairs are semantic-free. These results suggest that a semantic-structure model may be implemented as an alternative scoring in future editions of the WMS to facilitate interpretation.

PMID:34929041 | DOI:10.1093/arclin/acab093

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Nevin Manimala Statistics

Mycobacterium tuberculosis-specific T cell responses are impaired during late pregnancy with elevated biomarkers of tuberculosis risk postpartum

J Infect Dis. 2021 Dec 20:jiab614. doi: 10.1093/infdis/jiab614. Online ahead of print.

ABSTRACT

BACKGROUND: Pregnancy is a risk factor for progression from latent tuberculosis infection (LTBI) to symptomatic tuberculosis (TB). However, how pregnancy influences T cell responses to M. tuberculosis (Mtb) is unknown.

METHODS: We measured Mtb-specific cytokines, T-cell memory markers, and overall CD4+ and CD8+ T-cell activation by flow cytometry from 49 women (18 with and 31 without HIV) who became pregnant while enrolled in a randomized controlled trial of pre-exposure prophylaxis for HIV prevention. We analyzed these data using COMPASS, an established statistical method for evaluating overall antigen-specific T cell responses.

RESULTS: Pregnant women with latent TB infection demonstrated significantly diminished Mtb-specific CD4+ cytokine responses in the third trimester (COMPASS score (PFS) 0.07) compared before (PFS 0.15), during (PFS 0.13 and 0.16), and after pregnancy (PFS 0.14; p = 0.0084, Kruskal-Wallis test). Paradoxically, Mtb-specific CD8+ cytokines and nonspecifically activated T-cells increased during late pregnancy. Nonspecific T-cell activation, a validated biomarker for progression from LTBI to TB disease, was increased in LTBI+ women postpartum, compared with LTBI- women.

CONCLUSIONS: Pregnancy-related functional T-cell changes were most pronounced during late pregnancy. Mtb-specific T-cell changes during pregnancy and postpartum, increases in immune activation may contribute to increased risk for TB progression in the postpartum period.

PMID:34929030 | DOI:10.1093/infdis/jiab614

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Nevin Manimala Statistics

Effects of Class II elastics during growth on the functional occlusal plane according to skeletal pattern and extraction vs nonextraction

Angle Orthod. 2021 Dec 20. doi: 10.2319/051521-381.1. Online ahead of print.

ABSTRACT

OBJECTIVES: To investigate the effect of Class II intermaxillary elastics on the functional occlusal plane (FOP) of growing patients.

MATERIALS AND METHODS: A total of 50 participants aged 11 to 16 years were selected from a university clinic archive >1-year after treatment and after undergoing 6 months of Class II elastic wear, taking pretreatment (T0) and posttreatment (T1) lateral cephalometric radiographs, and consenting to participate at recall (T2). Participants were divided into 3 groups according to skeletal pattern or into 2 groups according to treatment with extraction (E) or nonextraction (NE). Angular changes of FOP relative to the Sella-Nasion (SN), mandibular plane (MP), and Frankfort horizontal (FH) were compared within and between groups.

RESULTS: A statistically significant reduction of FOP-SN/FH, but not of FOP-MP, was found from T0-T1-T2 when all patients were grouped together. FOP-SN/MP/FH was significantly the largest in the patients with a hyperdivergent skeletal pattern, but lowest in the patients with a hypodivergent skeletal pattern at T0, T1, and T2 (P < .032). FOP-MP at T0-T2 was statistically larger in group E than in group NE (P < .02). No differences were found for FOP changes (change before treatment minus after treatment and change after treatment minus 1 year after treatment) between different skeletal patterns (P > .433) and treatment groups (P > .193).

CONCLUSIONS: Use of Class II elastics during the growth period was not found to show adverse effects on FOP rotation. Neither skeletal pattern nor treatment modality differed in the response to Class II elastics with regard to FOP changes. Individual patient growth pattern must be taken into consideration when treatment planning the use of Class II elastics. Orthodontists should take into account individual skeletal and growth patterns while using Class II elastics.

PMID:34929025 | DOI:10.2319/051521-381.1

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Nevin Manimala Statistics

Video-based quantification of human movement frequency using pose estimation: A pilot study

PLoS One. 2021 Dec 20;16(12):e0261450. doi: 10.1371/journal.pone.0261450. eCollection 2021.

ABSTRACT

Assessment of repetitive movements (e.g., finger tapping) is a hallmark of motor examinations in several neurologic populations. These assessments are traditionally performed by a human rater via visual inspection; however, advances in computer vision offer potential for remote, quantitative assessment using simple video recordings. Here, we evaluated a pose estimation approach for measurement of human movement frequency from smartphone videos. Ten healthy young participants provided videos of themselves performing five repetitive movement tasks (finger tapping, hand open/close, hand pronation/supination, toe tapping, leg agility) at four target frequencies (1-4 Hz). We assessed the ability of a workflow that incorporated OpenPose (a freely available whole-body pose estimation algorithm) to estimate movement frequencies by comparing against manual frame-by-frame (i.e., ground-truth) measurements for all tasks and target frequencies using repeated measures ANOVA, Pearson’s correlations, and intraclass correlations. Our workflow produced largely accurate estimates of movement frequencies; only the hand open/close task showed a significant difference in the frequencies estimated by pose estimation and manual measurement (while statistically significant, these differences were small in magnitude). All other tasks and frequencies showed no significant differences between pose estimation and manual measurement. Pose estimation-based detections of individual events (e.g., finger taps, hand closures) showed strong correlations (all r>0.99) with manual detections for all tasks and frequencies. In summary, our pose estimation-based workflow accurately tracked repetitive movements in healthy adults across a range of tasks and movement frequencies. Future work will test this approach as a fast, quantitative, video-based approach to assessment of repetitive movements in clinical populations.

PMID:34929012 | DOI:10.1371/journal.pone.0261450

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The pigtail macaque (Macaca nemestrina) model of COVID-19 reproduces diverse clinical outcomes and reveals new and complex signatures of disease

PLoS Pathog. 2021 Dec 20;17(12):e1010162. doi: 10.1371/journal.ppat.1010162. Online ahead of print.

ABSTRACT

The novel coronavirus SARS-CoV-2, the causative agent of COVID-19 disease, has killed over five million people worldwide as of December 2021 with infections rising again due to the emergence of highly transmissible variants. Animal models that faithfully recapitulate human disease are critical for assessing SARS-CoV-2 viral and immune dynamics, for understanding mechanisms of disease, and for testing vaccines and therapeutics. Pigtail macaques (PTM, Macaca nemestrina) demonstrate a rapid and severe disease course when infected with simian immunodeficiency virus (SIV), including the development of severe cardiovascular symptoms that are pertinent to COVID-19 manifestations in humans. We thus proposed this species may likewise exhibit severe COVID-19 disease upon infection with SARS-CoV-2. Here, we extensively studied a cohort of SARS-CoV-2-infected PTM euthanized either 6- or 21-days after respiratory viral challenge. We show that PTM demonstrate largely mild-to-moderate COVID-19 disease. Pulmonary infiltrates were dominated by T cells, including CD4+ T cells that upregulate CD8 and express cytotoxic molecules, as well as virus-targeting T cells that were predominantly CD4+. We also noted increases in inflammatory and coagulation markers in blood, pulmonary pathologic lesions, and the development of neutralizing antibodies. Together, our data demonstrate that SARS-CoV-2 infection of PTM recapitulates important features of COVID-19 and reveals new immune and viral dynamics and thus may serve as a useful animal model for studying pathogenesis and testing vaccines and therapeutics.

PMID:34929014 | DOI:10.1371/journal.ppat.1010162

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Dynamics of latent HIV under clonal expansion

PLoS Pathog. 2021 Dec 20;17(12):e1010165. doi: 10.1371/journal.ppat.1010165. Online ahead of print.

ABSTRACT

The HIV latent reservoir exhibits slow decay on antiretroviral therapy (ART), impacted by homeostatic proliferation and activation. How these processes contribute to the total dynamic while also producing the observed profile of sampled latent clone sizes is unclear. An agent-based model was developed that tracks individual latent clones, incorporating homeostatic proliferation of cells and activation of clones. The model was calibrated to produce observed latent reservoir dynamics as well as observed clonal size profiles. Simulations were compared to previously published latent HIV integration data from 5 adults and 3 children. The model simulations reproduced reservoir dynamics as well as generating residual plasma viremia levels (pVL) consistent with observations on ART. Over 382 Latin Hypercube Sample simulations, the median latent reservoir grew by only 0.3 log10 over the 10 years prior to ART initiation, after which time it decreased with a half-life of 15 years, despite number of clones decreasing at a faster rate. Activation produced a maximum size of genetically intact clones of around one million cells. The individual simulation that best reproduced the sampled clone profile, produced a reservoir that decayed with a 13.9 year half-life and where pVL, produced mainly from proliferation, decayed with a half-life of 10.8 years. These slow decay rates were achieved with mean cell life-spans of only 14.2 months, due to expansion of the reservoir through proliferation and activation. Although the reservoir decayed on ART, a number of clones increased in size more than 4,000-fold. While small sampled clones may have expanded through proliferation, the large sizes exclusively arose from activation. Simulations where homeostatic proliferation contributed more to pVL than activation, produced pVL that was less variable over time and exhibited fewer viral blips. While homeostatic proliferation adds to the latent reservoir, activation can both add and remove latent cells. Latent activation can produce large clones, where these may have been seeded much earlier than when first sampled. Elimination of the reservoir is complicated by expanding clones whose dynamic differ considerably to that of the entire reservoir.

PMID:34929000 | DOI:10.1371/journal.ppat.1010165

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Nevin Manimala Statistics

Normal manual straight ahead pointing in Complex Regional Pain Syndrome

PLoS One. 2021 Dec 20;16(12):e0261614. doi: 10.1371/journal.pone.0261614. eCollection 2021.

ABSTRACT

There is evidence to suggest that people with Complex Regional Pain Syndrome (CRPS) can have altered body representations and spatial cognition. One way of studying these cognitive functions is through manual straight ahead (MSA) pointing, in which participants are required to point straight ahead of their perceived body midline without visual feedback of the hand. We therefore compared endpoint errors from MSA pointing between people with CRPS (n = 17) and matched controls (n = 18), and examined the effect of the arm used (Side of Body; affected/non-dominant, non-affected/dominant). For all participants, pointing errors were biased towards the hand being used. We found moderate evidence of no difference between Groups on endpoint errors, and moderate evidence of no interaction with Side of Body. The differences in variability between Groups were non-significant/inconclusive. Correlational analyses showed no evidence of a relationship between MSA endpoint errors and clinical parameters (e.g. CRPS severity, duration, pain) or questionnaire measures (e.g. body representation, “neglect-like symptoms”, upper limb disability). This study is consistent with earlier findings of no difference between people with CRPS and controls on MSA endpoint errors, and is the first to provide statistical evidence of similar performance of these two groups. Our results do not support a relationship between clinical or self-reported measures (e.g. “neglect-like symptoms”) and any directional biases in MSA. Our findings may have implications for understanding neurocognitive changes in CRPS.

PMID:34929004 | DOI:10.1371/journal.pone.0261614

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Implementation of a neonatal hepatitis B immunization program in rural Karenni State, Myanmar: A mixed-methods study

PLoS One. 2021 Dec 20;16(12):e0261470. doi: 10.1371/journal.pone.0261470. eCollection 2021.

ABSTRACT

BACKGROUND: Hepatitis B infection is a major health concern in Myanmar. Hepatitis B birth dose vaccination to prevent mother-to-child transmission is not universal, especially in births outside of health care facilities. Little is documented about delivery of immunization programs in rural Myanmar or in conflict-affected regions. To address this gap, this study describes the implementation of a novel community delivered neonatal hepatitis B immunization program in rural Karenni State, Myanmar.

METHODS: A mixed-methods study assessed the effectiveness and feasibility of hepatitis B birth dose immunization program. 1000 pregnant women were screened for hepatitis B virus (HBV) infection using point of care testing. Neonates of HBV positive mothers were immunized with a three dose HBV vaccine schedule at birth, 1, and 6 months of age. HBV testing was completed for children at 9 months to assess for infection. Descriptive statistics were collected including demographic data of mothers, neonatal vaccination schedule completion, and child HBV positivity at 9 months. Qualitative data examining barriers to implementation were collected through semi-structured interviews, participant-observation, and analysis of program documents. Themes were codified and mapped onto the Consolidated Framework for Implementation Research.

RESULTS: 46 pregnant women tested HBV positive leading to 40 live births. 39 women-child dyads were followed until the 9-month age mark. With the exception of two neonates who received their birth dose past 24 hours, all children received their vaccines on time. None of the 39 children tested positive for HBV at nine months. Themes regarding barriers included adaptability of the program to the rural setting, friction with other stakeholders and not meeting all needs of the community. Identified strengths included good communication and leadership within the implementing ethnic health organization.

CONCLUSION: A community delivered neonatal HBV vaccination program by ethnic health organizations is feasible and effective in rural Myanmar.

PMID:34928996 | DOI:10.1371/journal.pone.0261470

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Nevin Manimala Statistics

Mean square displacement for a discrete centroid model of cell motion

PLoS One. 2021 Dec 20;16(12):e0261021. doi: 10.1371/journal.pone.0261021. eCollection 2021.

ABSTRACT

The mean square displacement (MSD) is an important statistical measure on a stochastic process or a trajectory. In this paper we find an approximation to the mean square displacement for a model of cell motion. The model is a discrete-time jump process which approximates a force-based model for cell motion. In cell motion, the mean square displacement not only gives a measure of overall drift, but it is also an indicator of mode of transport. The key to finding the approximation is to find the mean square displacement for a subset of the state space and use it as an approximation for the entire state space. We give some intuition as to why this is an unexpectedly good approximation. A lower bound and upper bound for the mean square displacement are also given. We show that, although the upper bound is far from the computed mean square displacement, in rare cases the large displacements are approached.

PMID:34928985 | DOI:10.1371/journal.pone.0261021

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Nevin Manimala Statistics

The relationship between the nurses’ work environment and the quality and safe nursing care: Slovenian study using the RN4CAST questionnaire

PLoS One. 2021 Dec 20;16(12):e0261466. doi: 10.1371/journal.pone.0261466. eCollection 2021.

ABSTRACT

INTRODUCTION: The safety and quality of patient care are basic guidelines in finding new and improved solutions in nursing. Important and influential factors shape the nurses’ work environment in hospitals.

PURPOSE: With the study, we intended to investigate whether the perception of nurses’ work environment is related to the safety culture and the quality of patient care and whether it differs according to nurses’ level of education.

METHODS OF WORK: The study with a quantitative research method was conducted at the six clinical departments of the University Medical Centre, Ljubljana in 2019. We used a survey questionnaire from the European survey Nurse forecasting in Europe (RN4CAST).

RESULTS: 270 nurses were included in the study. The response rate was 54%. The study confirmed that there is a correlation between the assessment of the nurses’ work environment and the general assessment of patient safety (r = 0.36; p <0.001), the general assessment of the quality of nursing care (r = 0.32; p <0.001), the confidence in patient self-care at discharge (r = 0.29; p <0.001) and the quality of patient care in the previous year (r = 0.27; p = 0.001). The results showed frequent verbal abuse of nurses, in 44.9% by patients and their relatives and in 35.4% by staff. Graduate nurses rated the work environment more negatively than healthcare technicians (p = 0.003).

DISCUSSION AND CONCLUSION: We confirmed the correlation between the assessment of nurses’ work environment and patient safety and the quality of health care, and that employees’ education influences the assessment and perception of the work environment.

PMID:34928992 | DOI:10.1371/journal.pone.0261466