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1.
Surg Neurol Int ; 15: 181, 2024.
Article in English | MEDLINE | ID: mdl-38840612

ABSTRACT

Background: Frameless image-guided radiosurgery (IGRS) is an effective and non-invasive method of treating patients who are unresponsive to medical management for trigeminal neuralgia (TN). This study evaluated the use of frameless IGRS to treat patients with medically refractory TN. Methods: We performed a retrospective review of records of 116 patients diagnosed with TN who underwent frameless IGRS using a linear accelerator (LINAC) over 10 years (March 2012-February 2023). All patients had failed medical management for TN. Facial pain was graded using the Barrow Neurological Institute (BNI) scoring system. Each patient received a BNI score before frameless IGRS and following treatment. Failure was defined as a BNI score IV-V at the last follow-up and/or undergoing a salvage procedure following IGRS. Results: All patients had a BNI score of either IV or V before the frameless IGRS. The mean follow-up duration for all 116 patients following IGRS was 44.1 months. Most patients (81 [69.8%]) had not undergone surgery (microvascular decompression [MVD] or rhizotomy) or stereotactic radiosurgery (SRS) for TN before frameless IGRS. A total of 41 (35.3%) patients underwent a salvage procedure (MVD, rhizotomy, or an additional IGRS) following frameless IGRS. The mean duration between the initial frameless IGRS and salvage procedure was 20.1 months. At the last follow-up, a total of 110 (94.8%) patients had a BNI score of I-III. No complications were reported after the frameless IGRS. The BNI score at the last follow-up was lower compared to the initial BNI for patients regardless of prior intervention (P < 0.001). Patients who failed IGRS had a higher BNI score at the last follow-up compared to those who did not fail IGRS (2.8 vs. 2.5, P = 0.05). Patients with pain relief had a shorter follow-up compared to those with pain refractory to SRS (38.0 vs. 55.1, P = 0.005). Conclusion: In this large cohort of patients with medically refractory TN, frameless IGRS resulted in durable pain control in the majority of patients without any toxicity.

2.
Physiol Genomics ; 56(7): 457-468, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38738316

ABSTRACT

Military training provides insight into metabolic responses under unique physiological demands that can be comprehensively characterized by global metabolomic profiling to identify potential strategies for improving performance. This study identified shared changes in metabolomic profiles across three distinct military training exercises, varying in magnitude and type of stress. Blood samples collected before and after three real or simulated military training exercises were analyzed using the same untargeted metabolomic profiling platform. Exercises included a 2-wk survival training course (ST, n = 36), a 4-day cross-country ski march arctic training (AT, n = 24), and a 28-day controlled diet- and exercise-induced energy deficit (CED, n = 26). Log2-fold changes of greater than ±1 in 191, 121, and 64 metabolites were identified in the ST, AT, and CED datasets, respectively. Most metabolite changes were within the lipid (57-63%) and amino acid metabolism (18-19%) pathways and changes in 87 were shared across studies. The largest and most consistent increases in shared metabolites were found in the acylcarnitine, fatty acid, ketone, and glutathione metabolism pathways, whereas the largest decreases were in the diacylglycerol and urea cycle metabolism pathways. Multiple shared metabolites were consistently correlated with biomarkers of inflammation, tissue damage, and anabolic hormones across studies. These three studies of real and simulated military training revealed overlapping alterations in metabolomic profiles despite differences in environment and the stressors involved. Consistent changes in metabolites related to lipid metabolism, ketogenesis, and oxidative stress suggest a potential common metabolomic signature associated with inflammation, tissue damage, and suppression of anabolic signaling that may characterize the unique physiological demands of military training.NEW & NOTEWORTHY The extent to which metabolomic responses are shared across diverse military training environments is unknown. Global metabolomic profiling across three distinct military training exercises identified shared metabolic responses with the largest changes observed for metabolites related to fatty acids, acylcarnitines, ketone metabolism, and oxidative stress. These changes also correlated with alterations in markers of tissue damage, inflammation, and anabolic signaling and comprise a potential common metabolomic signature underlying the unique physiological demands of military training.


Subject(s)
Metabolome , Metabolomics , Military Personnel , Humans , Metabolomics/methods , Male , Young Adult , Stress, Physiological/physiology , Adult , Exercise/physiology , Carnitine/analogs & derivatives , Carnitine/blood
3.
Dig Dis Sci ; 69(5): 1722-1730, 2024 May.
Article in English | MEDLINE | ID: mdl-38594432

ABSTRACT

INTRODUCTION: Patients with gastroparesis (Gp) have symptoms with or without a cyclic pattern. This retrospective study evaluates differences in cyclic vs. non-cyclic symptoms of Gp by analyzing mucosal electrogastrogram (mEG), familial dysautonomias, and response to gastric stimulation. METHODS: 37 patients with drug refractory Gp, 7 male and 30 female, with a mean age of 41.4 years, were studied. 18 had diabetes mellitus, 25 had cyclic (Cyc), and 12 had a non-cyclic (NoCyc) pattern of symptoms. Patients underwent temporary mucosal gastric stimulator (tGES) placement, which was done as a trial before permanent stimulator (GES) placement. Electrogastrogram (EGG) by mucosal (mEG) measures, including frequency, amplitude, and frequency-amplitude ratio (FAR), were pre- and post-tGES. Patients' history of personal and familial dysautonomias, quality of life, and symptom scores were recorded. Baseline vs. follow-ups were compared by paired t tests and McNemar's tests. T tests contrasted symptom scores, gastric emptying tests (GET), and mEG measures, while chi-squared tests deciphered comorbidity differences between two groups and univariate and multivariate analyses. RESULTS: There were significantly more patients with diabetes in the Cyc group vs. the NoCyc group. Using a 1 point in symptom outcome, 18 patients did not improve and 19 did improve with tGES. Using univariable analysis, with the cyclic pattern as a predictor, patients exhibiting a cyclic pattern had an odds ratio of 0.22 (95% CI 0.05-0.81, p = 0.054) for achieving an improvement of at least one unit in vomiting at follow-up from baseline. The mucosal electrogastrogram frequency to amplitude ratio (FAR) for the "not Improved" group was 19.6 [3.5, 33.6], whereas, for the "Improved" group, it was 54.3 [25.6, 72.5] with a p-value of 0.049. For multivariate logistic regression, accounting for sex and age squared, patients exhibiting a cyclic pattern had an adjusted odds ratio (OR) of 0.16 (95% CI 0.03-0.81, p = 0.027) for achieving an improvement of at least one unit in vomiting at follow-up from baseline. The two groups had no significant differences in the personal or inherited history of investigated familial patterns. CONCLUSION: This study shows differences in Gp patients with Cyc vs. NoCyc symptoms in several areas. Larger studies are needed to elicit further differences between the two groups about cycles of symptoms, EGG, findings, familial patterns, and response to mucosal GES.


Subject(s)
Electric Stimulation Therapy , Gastric Emptying , Gastroparesis , Humans , Gastroparesis/therapy , Gastroparesis/physiopathology , Gastroparesis/diagnosis , Female , Male , Adult , Retrospective Studies , Middle Aged , Gastric Emptying/physiology , Electric Stimulation Therapy/methods , Treatment Outcome
4.
Article in English | MEDLINE | ID: mdl-38609673

ABSTRACT

The study aimed to provide quantitative information on the utilization of MRI transverse relaxation time constant (MRI-T2) of leg muscles in DMD clinical trials by developing multivariate disease progression models of Duchenne muscular dystrophy (DMD) using 6-min walk distance (6MWD) and MRI-T2. Clinical data were collected from the prospective and longitudinal ImagingNMD study. Disease progression models were developed by a nonlinear mixed-effect modeling approach. Univariate models of 6MWD and MRI-T2 of five muscles were developed separately. Age at assessment was the time metric. Multivariate models were developed by estimating the correlation of 6MWD and MRI-T2 model variables. Full model estimation approach for covariate analysis and five-fold cross validation were conducted. Simulations were performed to compare the models and predict the covariate effects on the trajectories of 6MWD and MRI-T2. Sigmoid Imax and Emax models best captured the profiles of 6MWD and MRI-T2 over age. Steroid use, baseline 6MWD, and baseline MRI-T2 were significant covariates. The median age at which 6MWD is half of its maximum decrease in the five models was similar, while the median age at which MRI-T2 is half of its maximum increase varied depending on the type of muscle. The models connecting 6MWD and MRI-T2 successfully quantified how individual characteristics alter disease trajectories. The models demonstrate a plausible correlation between 6MWD and MRI-T2, supporting the use of MRI-T2. The developed models will guide drug developers in using the MRI-T2 to most efficient use in DMD clinical trials.

5.
Age Ageing ; 53(3)2024 03 01.
Article in English | MEDLINE | ID: mdl-38497237

ABSTRACT

BACKGROUND: Limited evidence exists on the short- and long-term safety of discontinuing versus continuing chronic opioid therapy (COT) among patients with Alzheimer's disease and related dementias (ADRD). METHODS: This cohort study was conducted among 162,677 older residents with ADRD and receipt of COT using a 100% Medicare nursing home sample. Discontinuation of COT was defined as no opioid refills for ≥90 days. Primary outcomes were rates of pain-related hospitalisation, pain-related emergency department visit, injury, opioid use disorder (OUD) and opioid overdose (OD) measured by diagnosis codes at quarterly intervals during 1- and 2-year follow-ups. Poisson regression models were fit using generalised estimating equations with inverse probability of treatment weights to model quarterly outcome rates between residents who discontinued versus continued COT. RESULTS: The study sample consisted of 218,040 resident episodes with COT; of these episodes, 180,916 residents (83%) continued COT, whereas 37,124 residents (17%) subsequently discontinued COT. Discontinuing (vs. continuing) COT was associated with higher rates of all outcomes in the first quarter, but these associations attenuated over time. The adjusted rates of injury, OUD and OD were 0, 69 and 60% lower at the 1-year follow-up and 11, 81 and 79% lower at the 2-year follow-up, respectively, for residents who discontinued versus continued COT, with no difference in the adjusted rates of pain-related hospitalisations or emergency department visits. CONCLUSIONS: The rates of adverse outcomes were higher in the first quarter but lower or non-differential at 1-year and 2-year follow-ups between COT discontinuers versus continuers among older residents with ADRD.


Subject(s)
Alzheimer Disease , Opioid-Related Disorders , Humans , Aged , United States/epidemiology , Analgesics, Opioid/adverse effects , Cohort Studies , Alzheimer Disease/diagnosis , Alzheimer Disease/drug therapy , Alzheimer Disease/epidemiology , Medicare , Opioid-Related Disorders/drug therapy , Pain/drug therapy , Retrospective Studies
6.
Biostatistics ; 25(3): 919-932, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38332624

ABSTRACT

Mediation analysis with contemporaneously observed multiple mediators is a significant area of causal inference. Recent approaches for multiple mediators are often based on parametric models and thus may suffer from model misspecification. Also, much of the existing literature either only allow estimation of the joint mediation effect or estimate the joint mediation effect just as the sum of individual mediator effects, ignoring the interaction among the mediators. In this article, we propose a novel Bayesian nonparametric method that overcomes the two aforementioned drawbacks. We model the joint distribution of the observed data (outcome, mediators, treatment, and confounders) flexibly using an enriched Dirichlet process mixture with three levels. We use standardization (g-computation) to compute all possible mediation effects, including pairwise and all other possible interaction among the mediators. We thoroughly explore our method via simulations and apply our method to a mental health data from Wisconsin Longitudinal Study, where we estimate how the effect of births from unintended pregnancies on later life mental depression (CES-D) among the mothers is mediated through lack of self-acceptance and autonomy, employment instability, lack of social participation, and increased family stress. Our method identified significant individual mediators, along with some significant pairwise effects.


Subject(s)
Bayes Theorem , Humans , Mediation Analysis , Female , Longitudinal Studies , Models, Statistical , Mental Health
7.
Cureus ; 16(1): e53001, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38406061

ABSTRACT

BACKGROUND: Patients with recurrent glioblastoma (GBM) have limited treatment options. This study determined whether patients with recurrent GBM treated with initial radiation/temozolomide (TMZ) and reirradiation using fractionated stereotactic radiotherapy (FSRT) had improved outcomes. MATERIALS AND METHODS: We identified 95 patients with recurrent GBM, 50 of whom underwent FSRT at recurrence and 45 who had systemic treatment only (control). The median total FSRT dose at the time of GBM recurrence was 30 Gy in five fractions of the gadolinium-enhanced tumor only. RESULTS: With a median follow-up of 18 months, the progression-free survival (PFS) and overall survival (OS) following initial GBM diagnosis were longer in the reirradiation group compared to the control group (13.5 vs. 7.5 months [p=0.001] and 24.6 vs. 12.6 months [p<0.001], respectively). For patients who underwent reirradiation, the median time interval between the end of the initial radiation and reirradiation was 15.2 months. The median OS after GBM recurrence was longer in the reirradiation group versus the control group (9.9 vs. 3.5 months [p<0.001]), with a one-year OS survival rate of 22%. The hazard ratio for death of patients in the reirradiation group was 0.31 [0.19-0.50]. The reirradiation group had a higher percentage of patients who received bevacizumab (BEV, 62.0% vs. 28.9%, p=0.002) and a lower percentage of patients whose TMZ was discontinued due to toxicity (8.0% vs. 28.9%, p=0.017) compared to the control group. CONCLUSIONS: Reirradiation utilizing FSRT was associated with improved PFS and OS after GBM recurrence compared to the control group who did not receive additional irradiation.

8.
Ann Clin Transl Neurol ; 11(1): 67-78, 2024 01.
Article in English | MEDLINE | ID: mdl-37932907

ABSTRACT

OBJECTIVE: Magnetic resonance (MR) measures of muscle quality are highly sensitive to disease progression and predictive of meaningful functional milestones in Duchenne muscular dystrophy (DMD). This investigation aimed to establish the reproducibility, responsiveness to disease progression, and minimum clinically important difference (MCID) for multiple MR biomarkers at different disease stages in DMD using a large natural history dataset. METHODS: Longitudinal MR imaging and spectroscopy outcomes and ambulatory function were measured in 180 individuals with DMD at three sites, including repeated measurements on two separate days (within 1 week) in 111 participants. These data were used to calculate day-to-day reproducibility, responsiveness (standardized response mean, SRM), minimum detectable change, and MCID. A survey of experts was also performed. RESULTS: MR spectroscopy fat fraction (FF), as well as MR imaging transverse relaxation time (MRI-T2 ), measures performed in multiple leg muscles, and had high reproducibility (Pearson's R > 0.95). Responsiveness to disease progression varied by disease stage across muscles. The average FF from upper and lower leg muscles was highly responsive (SRM > 0.9) in both ambulatory and nonambulatory individuals. MCID estimated from the distribution of scores, by anchoring to function, and via expert opinion was between 0.01 and 0.05 for FF and between 0.8 and 3.7 ms for MRI-T2 . INTERPRETATION: MR measures of FF and MRI T2 are reliable and highly responsive to disease progression. The MCID for MR measures is less than or equal to the typical annualized change. These results confirm the suitability of these measures for use in DMD and potentially other muscular dystrophies.


Subject(s)
Muscular Dystrophy, Duchenne , Humans , Muscular Dystrophy, Duchenne/diagnostic imaging , Clinical Relevance , Reproducibility of Results , Magnetic Resonance Spectroscopy/methods , Magnetic Resonance Imaging/methods , Biomarkers , Disease Progression
9.
Alzheimers Dement ; 20(2): 1026-1037, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37855270

ABSTRACT

INTRODUCTION: Limited evidence exists on the associations of discontinuing versus continuing long-term opioid therapy (LTOT) with pain intensity, physical function, and depression among patients with Alzheimer's disease and related dementias (ADRD). METHODS: A cohort study among 138,059 older residents with mild-to-moderate ADRD and receipt of LTOT was conducted using a 100% Medicare nursing home sample. Discontinuation of LTOT was defined as no opioid refills for ≥ 60 days. Outcomes were worsening pain, physical function, and depression from baseline to quarterly assessments during 1- and 2-year follow-ups. RESULTS: The adjusted odds of worsening pain and depressive symptoms were 29% and 5% lower at the 1-year follow-up and 35% and 9% lower at the 2-year follow-up for residents who discontinued versus continued LTOT, with no difference in physical function. DISCUSSION: Discontinuing LTOT was associated with lower short- and long-term worsening pain and depressive symptoms than continuing LTOT among older residents with ADRD. HIGHLIGHTS: Discontinuing long-term opioid therapy (LTOT) was associated with lower short- and long-term worsening pain. Discontinuing LTOT was related to lower short- and long-term worsening depression. Discontinuing LTOT was not associated with short- and long-term physical function.


Subject(s)
Alzheimer Disease , Chronic Pain , Humans , Aged , United States , Alzheimer Disease/complications , Alzheimer Disease/drug therapy , Analgesics, Opioid/therapeutic use , Cohort Studies , Depression/drug therapy , Pain Measurement , Retrospective Studies , Chronic Pain/drug therapy , Medicare
10.
Elife ; 122023 12 12.
Article in English | MEDLINE | ID: mdl-38085657

ABSTRACT

Microglial endolysosomal (dys)function is strongly implicated in neurodegenerative disease. Transcriptomic studies show that a microglial state characterised by a set of genes involved in endolysosomal function is induced in both mouse Alzheimer's disease (AD) models and human AD brain, and that the emergence of this state is emphasised in females. Cst7 (encoding cystatin F) is among the most highly upregulated genes in these microglia. However, despite such striking and robust upregulation, the function of Cst7 in neurodegenerative disease is not understood. Here, we crossed Cst7-/- mice with the AppNL-G-F mouse to test the role of Cst7 in a model of amyloid-driven AD. Surprisingly, we found that Cst7 plays a sexually dimorphic role regulating microglia in this model. In females, Cst7-/-AppNL-G-F microglia had greater endolysosomal gene expression, lysosomal burden, and amyloid beta (Aß) burden in vivo and were more phagocytic in vitro. However, in males, Cst7-/-AppNL-G-F microglia were less inflammatory and had a reduction in lysosomal burden but had no change in Aß burden. Overall, our study reveals functional roles for one of the most commonly upregulated genes in microglia across disease models, and the sex-specific profiles of Cst7-/--altered microglial disease phenotypes. More broadly, the findings raise important implications for AD including crucial questions on sexual dimorphism in neurodegenerative disease and the interplay between endolysosomal and inflammatory pathways in AD pathology.


Subject(s)
Alzheimer Disease , Cystatins , Neurodegenerative Diseases , Animals , Female , Humans , Male , Mice , Alzheimer Disease/metabolism , Amyloid beta-Peptides/genetics , Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/metabolism , Cystatins/metabolism , Disease Models, Animal , Mice, Transgenic , Microglia/metabolism , Neurodegenerative Diseases/pathology
12.
Proc Natl Acad Sci U S A ; 120(44): e2305198120, 2023 Oct 31.
Article in English | MEDLINE | ID: mdl-37878716

ABSTRACT

Microbial communities perform essential ecosystem functions such as the remineralization of organic carbon that exists as biopolymers. The first step in mineralization is performed by biopolymer degraders, which harbor enzymes that can break down polymers into constituent oligo- or monomeric forms. The released nutrients not only allow degraders to grow, but also promote growth of cells that either consume the degradation products, i.e., exploiters, or consume metabolites released by the degraders or exploiters, i.e., scavengers. It is currently not clear how such remineralizing communities assemble at the microscale-how interactions between the different guilds influence their growth and spatial distribution, and hence the development and dynamics of the community. Here, we address this knowledge gap by studying marine microbial communities that grow on the abundant marine biopolymer alginate. We used batch growth assays and microfluidics coupled to time-lapse microscopy to quantitatively investigate growth and spatial distribution of single cells. We found that the presence of exploiters or scavengers alters the spatial distribution of degrader cells. In general, exploiters and scavengers-which we collectively refer to as cross-feeder cells-slowed down the growth of degrader cells. In addition, coexistence with cross-feeders altered the production of the extracellular enzymes that break down polymers by degrader cells. Our findings reveal that ecological interactions by nondegrading community members have a profound impact on the functions of microbial communities that remineralize carbon biopolymers in nature.


Subject(s)
Microbiota , Biopolymers , Social Behavior , Carbon , Microbial Interactions
13.
Biostatistics ; 2023 Oct 06.
Article in English | MEDLINE | ID: mdl-37805939

ABSTRACT

Joint modeling of longitudinal data such as quality of life data and survival data is important for palliative care researchers to draw efficient inferences because it can account for the associations between those two types of data. Modeling quality of life on a retrospective from death time scale is useful for investigators to interpret the analysis results of palliative care studies which have relatively short life expectancies. However, informative censoring remains a complex challenge for modeling quality of life on the retrospective time scale although it has been addressed for joint models on the prospective time scale. To fill this gap, we develop a novel joint modeling approach that can address the challenge by allowing informative censoring events to be dependent on patients' quality of life and survival through a random effect. There are two sub-models in our approach: a linear mixed effect model for the longitudinal quality of life and a competing-risk model for the death time and dropout time that share the same random effect as the longitudinal model. Our approach can provide unbiased estimates for parameters of interest by appropriately modeling the informative censoring time. Model performance is assessed with a simulation study and compared with existing approaches. A real-world study is presented to illustrate the application of the new approach.

14.
Stat Med ; 42(28): 5100-5112, 2023 12 10.
Article in English | MEDLINE | ID: mdl-37715594

ABSTRACT

Physical activity (PA) guidelines recommend that PA be accumulated in bouts of 10 minutes or more in duration. Recently, researchers have sought to better understand how participants in PA interventions increase their activity. Participants can increase their daily PA by increasing the number of PA bouts per day while keeping the duration of the bouts constant; they can keep the number of bouts constant but increase the duration of each bout; or participants can increase both the number of bouts and their duration. We propose a novel joint modeling framework for modeling PA bouts and their duration over time. Our joint model is comprised of two sub-models: a mixed-effects Poisson hurdle sub-model for the number of bouts per day and a mixed-effects location scale gamma regression sub-model to characterize the duration of the bouts and their variance. The model allows us to estimate how daily PA bouts and their duration vary together over the course of an intervention and by treatment condition and is specifically designed to capture the unique distributional features of bouted PA as measured by accelerometer: frequent measurements, zero-inflated bouts, and skewed bout durations. We apply our methods to the Make Better Choices study, a longitudinal lifestyle intervention trial to increase PA. We perform a simulation study to evaluate how well our model is able to estimate relationships between outcomes.


Subject(s)
Exercise , Life Style , Humans , Accelerometry/methods , Time Factors , Clinical Trials as Topic
15.
Cell Rep Med ; 4(9): 101175, 2023 09 19.
Article in English | MEDLINE | ID: mdl-37652017

ABSTRACT

Synapse loss correlates with cognitive decline in Alzheimer's disease (AD). Data from mouse models suggests microglia are important for synapse degeneration, but direct human evidence for any glial involvement in synapse removal in human AD remains to be established. Here we observe astrocytes and microglia from human brains contain greater amounts of synaptic protein in AD compared with non-disease controls, and that proximity to amyloid-ß plaques and the APOE4 risk gene exacerbate this effect. In culture, mouse and human astrocytes and primary mouse and human microglia phagocytose AD patient-derived synapses more than synapses from controls. Inhibiting interactions of MFG-E8 rescues the elevated engulfment of AD synapses by astrocytes and microglia without affecting control synapse uptake. Thus, AD promotes increased synapse ingestion by human glial cells at least in part via an MFG-E8 opsonophagocytic mechanism with potential for targeted therapeutic manipulation.


Subject(s)
Alzheimer Disease , Microglia , Animals , Humans , Mice , Astrocytes , Eating , Synapses
16.
CPT Pharmacometrics Syst Pharmacol ; 12(10): 1437-1449, 2023 10.
Article in English | MEDLINE | ID: mdl-37534782

ABSTRACT

Although regulatory agencies encourage inclusion of imaging biomarkers in clinical trials for Duchenne muscular dystrophy (DMD), industry receives minimal guidance on how to use these biomarkers most beneficially in trials. This study aims to identify the optimal use of muscle fat fraction biomarkers in DMD clinical trials through a quantitative disease-drug-trial modeling and simulation approach. We simultaneously developed two multivariate models quantifying the longitudinal associations between 6-minute walk distance (6MWD) and fat fraction measures from vastus lateralis and soleus muscles. We leveraged the longitudinal individual-level data collected for 10 years through the ImagingDMD study. Age of the individuals at assessment was chosen as the time metric. After the longitudinal dynamic of each measure was modeled separately, the selected univariate models were combined using correlation parameters. Covariates, including baseline scores of the measures and steroid use, were assessed using the full model approach. The nonlinear mixed-effects modeling was performed in Monolix. The final models showed reasonable precision of the parameter estimates. Simulation-based diagnostics and fivefold cross-validation further showed the model's adequacy. The multivariate models will guide drug developers on using fat fraction assessment most efficiently using available data, including the widely used 6MWD. The models will provide valuable information about how individual characteristics alter disease trajectories. We will extend the multivariate models to incorporate trial design parameters and hypothetical drug effects to inform better clinical trial designs through simulation, which will facilitate the design of clinical trials that are both more inclusive and more conclusive using fat fraction biomarkers.


Subject(s)
Muscular Dystrophy, Duchenne , Humans , Muscular Dystrophy, Duchenne/drug therapy , Magnetic Resonance Spectroscopy/methods , Magnetic Resonance Imaging/methods , Biomarkers , Outcome Assessment, Health Care
17.
AMRC Open Res ; 4: 22, 2023 Mar 23.
Article in English | MEDLINE | ID: mdl-37323472

ABSTRACT

Background: Effective development and retention of talented early-career researchers (ECRs) is essential to the continued success of biomedical science research fields. To this end, formal mentorship programmes (where researchers are paired with one or more mentors beyond their direct manager) have proven to be successful in providing support and expanding career development opportunities. However, many programmes are limited to pools of mentors and mentees within one institute or geographical area, highlighting that cross-regional connections may be a missed opportunity in many mentorship schemes. Methods: Here, we aimed to address this limitation through our pilot cross-regional mentorship scheme, creating reciprocal mentor-mentee pairings between two pre-established networks of Alzheimer's Research UK (ARUK) Network-associated researchers. We carefully created 21 mentor-mentee pairings between the Scotland and University College London (UCL) networks in 2021, with surveys conducted to assess mentor/mentee satisfaction with the programme. Results: Participants reported very high satisfaction with the nature of the pairings and the mentors' contribution to the career development of mentees; a majority also reported that the mentorship scheme increased their connections outside of their home network. Our assessment of this pilot programme is that it supports the utility of cross-regional mentorship schemes for ECR development. At the same time, we highlight the limitations of our programme and recommend areas for improvement in future programmes, including greater consideration of support for minoritized groups and the need for additional training for mentors. Conclusions: In conclusion, our pilot scheme generated successful and novel mentor-mentee pairings across pre-existing networks; both of which reported high satisfaction with pairings, ECR career and personal development, and the formation of new cross-network connections. This pilot may serve as a model for other networks of biomedical researchers, where existing networks within medical research charities can act as a scaffold to build new cross-regional career development opportunities for researchers.

18.
Biometrics ; 79(4): 3907-3915, 2023 12.
Article in English | MEDLINE | ID: mdl-37349969

ABSTRACT

In longitudinal studies, it is not uncommon to make multiple attempts to collect a measurement after baseline. Recording whether these attempts are successful provides useful information for the purposes of assessing missing data assumptions. This is because measurements from subjects who provide the data after numerous failed attempts may differ from those who provide the measurement after fewer attempts. Previous models for these designs were parametric and/or did not allow sensitivity analysis. For the former, there are always concerns about model misspecification and for the latter, sensitivity analysis is essential when conducting inference in the presence of missing data. Here, we propose a new approach which minimizes issues with model misspecification by using Bayesian nonparametrics for the observed data distribution. We also introduce a novel approach for identification and sensitivity analysis. We re-analyze the repeated attempts data from a clinical trial involving patients with severe mental illness and conduct simulations to better understand the properties of our approach.


Subject(s)
Mental Disorders , Models, Statistical , Humans , Bayes Theorem , Longitudinal Studies
19.
J Occup Environ Med ; 65(8): 655-662, 2023 08 01.
Article in English | MEDLINE | ID: mdl-37171095

ABSTRACT

OBJECTIVE: This study describes the clinical and electrodiagnostic (EDX) findings as well as occupations and hobbies in 613 patients diagnosed with carpal tunnel syndrome (CTS). METHODS: Patients with moderate, moderately severe, or severe CTS based on EDX criteria were included. RESULTS: The most common occupations included workers in offices, construction/maintenance, and assembly lines. The occupation severity scores were greatest in garment workers, musicians, and landscapers. Regardless of occupation, patient age and occupation duration were significantly correlated ( P < 0.001). Gardeners had the highest average severity score of the hobbies, followed by painters, those who sew, and individuals who perform house chores. CONCLUSIONS: Physicians should be aware of particular occupations and hobbies associated with a greater risk of severe CTS and offer modifications to their patients' work duties and hobbies to minimize the likelihood of developing severe CTS.


Subject(s)
Carpal Tunnel Syndrome , Humans , Carpal Tunnel Syndrome/diagnosis , Hobbies , Occupations
20.
J Pharmacol Exp Ther ; 386(2): 169-180, 2023 08.
Article in English | MEDLINE | ID: mdl-36918276

ABSTRACT

Type 2 diabetes (T2D) is a rising pandemic worldwide. Diet and lifestyle changes are typically the first intervention for T2D. When this intervention fails, the biguanide metformin is the most common pharmaceutical therapy. Yet its full mechanisms of action remain unknown. In this work, we applied an ultrahigh resolution, mass spectrometry-based platform for untargeted plasma metabolomics to human plasma samples from a case-control observational study of nondiabetic and well-controlled T2D subjects, the latter treated conservatively with metformin or diet and lifestyle changes only. No statistically significant differences existed in baseline demographic parameters, glucose control, or clinical markers of cardiovascular disease risk between the two T2D groups, which we hypothesized would allow the identification of circulating metabolites independently associated with treatment modality. Over 3000 blank-reduced metabolic features were detected, with the majority of annotated features being lipids or lipid-like molecules. Altered abundance of multiple fatty acids and phospholipids were found in T2D subjects treated with diet and lifestyle changes as compared with nondiabetic subjects, changes that were often reversed by metformin. Our findings provide direct evidence that metformin monotherapy alters the human plasma lipidome independent of T2D disease control and support a potential cardioprotective effect of metformin worthy of future study. SIGNIFICANCE STATEMENT: This work provides important new information on the systemic effects of metformin in type 2 diabetic subjects. We observed significant changes in the plasma lipidome with metformin therapy, with metabolite classes previously associated with cardiovascular disease risk significantly reduced as compared to diet and lifestyle changes. While cardiovascular disease risk was not a primary outcome of our study, our results provide a jumping-off point for future work into the cardioprotective effects of metformin, even in well-controlled type 2 diabetes.


Subject(s)
Cardiovascular Diseases , Diabetes Mellitus, Type 2 , Metformin , Humans , Diabetes Mellitus, Type 2/metabolism , Metformin/pharmacology , Metformin/therapeutic use , Hypoglycemic Agents/pharmacology , Hypoglycemic Agents/therapeutic use , Lipidomics , Glycemic Control , Cardiovascular Diseases/prevention & control , Cardiovascular Diseases/drug therapy , Pharmaceutical Preparations , Biomarkers , Blood Glucose/metabolism
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