Nevin Manimala

Stat Med. 2021 Oct 14. doi: 10.1002/sim.9214. Online ahead of print.

ABSTRACT

Alzheimer’s disease (AD) is a severe neurodegenerative disorder impairing multiple domains, for example, cognition and behavior. Assessing the risk of AD progression and initiating timely interventions at early stages are critical to improve the quality of life for AD patients. Due to the heterogeneous nature and complex mechanisms of AD, one single longitudinal outcome is insufficient to assess AD severity and disease progression. Therefore, AD studies collect multiple longitudinal outcomes, including cognitive and behavioral measurements, as well as structural brain images such as magnetic resonance imaging (MRI). How to utilize the multivariate longitudinal outcomes and MRI data to make efficient statistical inference and prediction is an open question. In this article, we propose a multivariate joint model with functional data (MJM-FD) framework that relates multiple correlated longitudinal outcomes to a survival outcome, and use the scalar-on-function regression method to include voxel-based whole-brain MRI data as functional predictors in both longitudinal and survival models. We adopt a Bayesian paradigm to make statistical inference and develop a dynamic prediction framework to predict an individual’s future longitudinal outcomes and risk of a survival event. We validate the MJM-FD framework through extensive simulation studies and apply it to the motivating Alzheimer’s Disease Neuroimaging Initiative (ADNI) study.

PMID:34649301 | DOI:10.1002/sim.9214

Rofo. 2021 Oct 14. doi: 10.1055/a-1545-4983. Online ahead of print.

ABSTRACT

PURPOSE: To evaluate the use of ultrasound (US) during catheter placement in interstitial brachytherapy (iBT) of abdominal malignancies as an alternative to computed tomography (CT) fluoroscopy.

MATERIALS AND METHODS: Catheter placement for CT-guided iBT was, if US visibility was sufficient, assisted by sonography in 52 consecutive patients with 82 lesions (liver N = 62; kidney N = 16; peritoneum N = 4) of various malignancies. We collected data on lesion visibility, location, depth, size, and dosimetry. Comparison of CT fluoroscopy versus US-assisted catheter placement was performed by Fisher’s exact test for frequencies and U-test for lesion visibility and dosimetric data. Factors predicting the utility of sonography were determined in a lesion-based multivariate regression analysis. A p-value < 0.05 was regarded as statistically significant.

RESULTS: 150 catheters (1 to 6 per lesion; mean diameter 3.6 ± 2.4 cm) were implanted. CT fluoroscopy was used for 44 catheters, and US was used for 106 catheters. Lesion visibility assessed by 5-point Likert scale was significantly better in US (median 2 vs. 3; p = 0.011) and effective dose was significantly reduced if US guidance was applicable (median 1.75 vs. 8.19 mSv; p = 0.014). In a multivariate regression analysis, we identified increased lesion size and caudal location within the target organ to independently predict the utility of ultrasound in catheter placement for iBT.

CONCLUSION: Sonography is a helpful technique to assist CT-guided interstitial brachytherapy of upper abdominal malignancies. Especially for larger lesions localized in the lower liver segments or lower half of the kidney, superior visibility can be expected. As the effective dose of the patient is also reduced, radiation exposure of the medical staff may be indirectly lowered.

KEY POINTS: · Ultrasound-assisted catheter placement in CT-guided brachytherapy of upper abdominal malignancies significantly improves lesion visibility.. · Predictors of successful ultrasound application are larger lesions within the lower portion of the liver and kidney.. · By reducing the need for CT fluoroscopy during intervention, radiation exposure to the medical staff may be indirectly lowered..

CITATION FORMAT: · Damm R, Damm R, Heinze C et al. Radioablation of Upper Abdominal Malignancies by CT-Guided, Interstitial HDR Brachytherapy: A Multivariate Analysis of Catheter Placement Assisted by Ultrasound Imaging. Fortschr Röntgenstr 2021; DOI: 10.1055/a-1545-4983.

PMID:34649287 | DOI:10.1055/a-1545-4983

Med Sci Sports Exerc. 2021 Jul 7. doi: 10.1249/MSS.0000000000002739. Online ahead of print.

ABSTRACT

PURPOSE: To describe changes in laboratory-assessed anthropometric and physiological characteristics, training volumes and competitive performance in national development-team cross-country (XC) skiers over a 25-month period, and to analyze whether changes in competitive performance could be predicted by changes in laboratory-assessed qualities and training volumes.

METHODS: Data collected over 25 months from 30 national development-team XC skiers (14 women, 16 men; age 18-23 y) were analyzed retrospectively using multivariate statistics. Anthropometric and physiological characteristics were assessed via dual-energy X-ray absorptiometry and incremental roller-ski treadmill tests, respectively. Total training volumes and distributions of low- and high-intensity training (LIT and HIT) were analyzed from online training diaries, and competitive performance was determined by International Ski Federation (FIS) distance and sprint points.

RESULTS: Whole- and upper-body lean mass increased in the full cohort of skiers (n = 30; both p < 0.05), while lower-body lean mass, whole-body fat mass, speed and oxygen uptake (V˙O2) at a blood lactate concentration (BLa) of 2 and 4 mmol·L-1, as well as time-trial (TT) completion time, power output and peak V˙O2, improved in the women only (all p < 0.05). Valid predictive models were identified for female skiers’ best FIS distance points (R2 = 0.81 / Q2 = 0.51) and changes in FIS distance points (R2 = 0.83 / Q2 = 0.54), with body mass, fat mass, lean mass, V˙O2peak and speed at a BLa of 4 mmol·L-1 identified as consistently important variables for projection.

CONCLUSION: The valid prediction of competitive performance was achieved for women only in distance events. This study suggests that improvements in body composition and aerobic capacity may be more beneficial for elite female development-level skiers than for their male counterparts. These results have implications for athlete selection and performance development.

PMID:34649265 | DOI:10.1249/MSS.0000000000002739

Dement Geriatr Cogn Disord. 2021 Oct 14:1-6. doi: 10.1159/000519581. Online ahead of print.

ABSTRACT

INTRODUCTION: Although early diagnosis has been recognized as a key strategy to improve outcomes of Alzheimer’s disease and related dementias (ADRD), the effect of receiving a diagnosis on patients’ well-being is not well understood. This study addresses this gap by examining if receiving a dementia diagnosis influences social relationships.

METHODS: Data from the 3 waves (2012, 2014, and 2016) of the Health and Retirement Study were utilized as part of this study. This study examined whether receiving a new diagnosis of ADRD changed subsequent social relationships (social networks, social engagement, and social support). Regression analyses with inverse probability weighting were performed to estimate the impact of receiving a dementia diagnosis on changes in social relationships.

RESULTS: Receiving a new diagnosis of ADRD reduced both informal and formal social engagement. We found no statistically significant impacts of receiving a diagnosis of ADRD on social networks and social support.

CONCLUSIONS: Results suggest that receiving a new diagnosis of ADRD may have unintended impacts on social relationships. Practitioners and policymakers should be aware of these consequences and should identify strategies to alleviate the negative impact of receiving a diagnosis of ADRD and methods to mobilize support networks after receiving a diagnosis.

PMID:34649243 | DOI:10.1159/000519581

Physiol Meas. 2021 Oct 14. doi: 10.1088/1361-6579/ac2fb7. Online ahead of print.

ABSTRACT

OBJECTIVE: The aim of this study was to find spectral differences of diagnostic interest in heart sound recordings of patients with coronary artery disease (CAD) and healthy subjects.

APPROACH: Heart sound recordings from three studies were pooled, and patients with clear diagnostic outcomes (positive: CAD and negative: Non-CAD) were selected for further analysis. Recordings from 1146 patients (191 CAD and 955 Non-CAD) were analyzed for spectral differences between the two groups using Welch’s spectral density estimate. Frequency spectra were estimated for systole and diastole segments, and time-frequency spectra were estimated for first (S1) and second (S2) heart sound segments. An ANCOVA model with terms for diagnosis, age, gender, and body mass index (BMI) was used to evaluate statistical significance of the diagnosis term for each time-frequency component.

MAIN RESULTS: Diastole and systole segments of CAD patients showed increased energy at frequencies 20-120 Hz; furthermore, this difference was statistically significant for the diastole. CAD patients showed decreased energy for the mid-S1 and mid-S2 segments and conversely increased energy before and after the valve sounds. Both S1 and S2 segments showed regions of statistically significant difference in the time-frequency spectra.

SIGNIFICANCE: Results from analysis of the diastole support findings of increased low-frequency energy from previous studies. Time-frequency components of S1 and S2 sounds showed that these two segments likely contain heretofore untapped information for risk assessment of CAD using phonocardiography; this should be considered in future works. Further development of features that build on these findings could lead to improved acoustic detection of CAD.

PMID:34649235 | DOI:10.1088/1361-6579/ac2fb7

Biomed Pharmacother. 2021 Oct 11;144:112308. doi: 10.1016/j.biopha.2021.112308. Online ahead of print.

ABSTRACT

INTRODUCTION: Extensive evidence suggests that alpha-lipoic acid (ALA) is effective in diabetic neuropathy pain management. However, little is known on its safety and efficacy in reducing idiopathic pain in normoglycemic subjects. The aim of this study was to evaluate ALA food supplement safety and efficacy in the reduction of different forms of idiopathic pain.

METHODS: Two-hundred and ten normoglycemic adults suffering from idiopathic pain (i.e. 57 subjects with primitive neuropathic pain, 141 subjects with arthralgia with unknown etiology, and 12 subjects with idiopathic myalgia) were randomized to receive placebo, 400 mg/day, or 800 mg/day of ALA. Participants underwent two visits (at baseline = t0, and after 2 months = t1) in which two validated questionaries for pain (numerical rating scale [NRS] and visual analogue scale [VAS]) were collected; fasting blood glucose assessment, adverse effects, and renal and hepatic toxicity were also monitored.

RESULTS: At t1, none of subjects treated with ALA reported a decreased glycemia or adverse effects. The treated subjects showed a significant reduction in NRS (p < 0.001) while the placebo group did not show any NRS reduction (p = 0.86). Similar results were also obtained for VAS. Statistical analysis aimed at detecting possible differences in NRS and VAS scores among treatment groups based on the source of pain did not reveal any significant effect.

CONCLUSIONS: Since the management of idiopathic pain is challenging for physicians, the use of ALA food supplements could be a feasible option, based on its safety and efficacy compared to commonly-used analgesic drugs.

PMID:34649217 | DOI:10.1016/j.biopha.2021.112308

J Environ Radioact. 2021 Oct 11;240:106756. doi: 10.1016/j.jenvrad.2021.106756. Online ahead of print.

ABSTRACT

The volumetric activity of the divalent ⁹⁰Sr ion in groundwater at the Chornobyl NPP industrial site ranges from 1 to 2 to 400-3800 Bq/l. The increase in groundwater radionuclides concentrations is associated with the reduced sorption properties of local sediments, which affect the migration capacity of radionuclides in the environment. The decrease of the ⁹⁰Sr sorption properties of sediments is caused by changes in the chemical composition of groundwater. A new statistical method has been performed. Method based on the Monte Carlo method in order to evaluate the correlations between the ⁹⁰Sr volumetric activity and the groundwater chemical composition components. Simulation results using this method suggest a correlation between the volumetric activity of ⁹⁰Sr, the concentrations cations, the pH, and the oxidation index (organic contents). A direct correlation was established between the volumetric activity of ⁹⁰Sr, Ca²⁺ concentrations and the pH of groundwater in the range from 7 to 12.4. It was revealed that the concentrations of Na⁺ and K⁺ do not affect the conditions of ⁹⁰Sr migration with groundwater. There is an inverse correlation between the concentration of ⁹⁰Sr and the oxidation index, which is an indirect indicator of the organic substances content in water. Thus, the presence of organic substances in the groundwater effectively promotes sorption of ⁹⁰Sr. The proposed method of geochemical statistics enables a quantitative assessment of groundwater monitoring results.

PMID:34649194 | DOI:10.1016/j.jenvrad.2021.106756

Diagn Microbiol Infect Dis. 2021 Jul 31;102(1):115513. doi: 10.1016/j.diagmicrobio.2021.115513. Online ahead of print.

ABSTRACT

Identification of asymptomatic patients is necessary to control the COVID-19 pandemic and testing is one of the measures to detect this population. We evaluated the clinical correlation of the DiaSorin Molecular Simplexa COVID-19 Direct (DiaSorin Molecular) and Roche Cobas 6800 SARS-CoV-2 (Roche) assays using 253 oropharyngeal (OP) swab specimens collected from asymptomatic patients. Agreement between DiaSorin Molecular and Roche was 97% (95% CI, 0.94 to 0.99), with a κ statistic of 0.90 (95% CI, 0.83 to 0.97) and a PPA of 89% (95% CI, 0.76 to 0.96) and NPA of 99% (95% CI, 0.97 to 0.99). Simple regression analysis of Ct values revealed a regression line of y = 1.065*X – 5.537 with a Pearson’s r of 0.8542, indicating a good correlation between both platforms. The DiaSorin Molecular assay demonstrates clinical performance comparable to that of Roche in this population.

PMID:34649190 | DOI:10.1016/j.diagmicrobio.2021.115513

Res Vet Sci. 2021 Sep 29;141:26-32. doi: 10.1016/j.rvsc.2021.09.013. Online ahead of print.

ABSTRACT

High-mobility group box-1 (HMGB1) is an intranuclear molecule that is released extracellularly in cytotoxic conditions. In acute pancreatitis, extracellular HMGB1 acts as a stimulating factor in the mechanism associated with pancreatic injury. To evaluate the prognostic property of serum HMGB1 levels at the time of diagnosis of pancreatitis, the blood samples collected over 10 months from canine patients in Seoul National University Veterinary Medical Teaching Hospital (n = 29). The HMGB1 levels were measured with ELISA kit and results were analyzed correlation with patient’s death, hospitalization cost and period. HMGB1 levels in patients with acute pancreatitis (mean = 76 ng/mL, standard deviation [SD] = 46.99 ng/mL) were higher than that of normal individuals (mean = 31.65 ng/mL, SD = 18.41 ng/mL, p = 0.0082). Similarly, non-survivors demonstrated statistically significant difference than the survivors (p = 0.008). Clinical severity of acute pancreatitis was categorized into three stages: mild, moderate, and severe based on the disease activity index (DAI). The HMGB1 levels and mortality were associated with moderate DAI (p = 0.0236). However, the correlation between serum HMGB1 and patients’ hospitalization period and cost were not found to be significant (R² = 0.01991). The evaluation of serum HMGB1 level at the time of diagnosis was identified as a potential prognostic factor to estimate the prognosis of acute pancreatitis in canines.

PMID:34649188 | DOI:10.1016/j.rvsc.2021.09.013

Gait Posture. 2021 Oct 6;91:48-51. doi: 10.1016/j.gaitpost.2021.10.001. Online ahead of print.

ABSTRACT

BACKGROUND: The Rizzoli Foot Model (RFM) and Oxford Foot Model (OFM) are used to analyze segmented foot kinematics with independent tracking markers. Alternatively, rigid marker clusters can be used to improve markers’ visualization and facilitate analyzing shod gait.

RESEARCH QUESTION: Are there differences in angles from the RFM and OFM, obtained with independent and clustered tracking markers, during the stance phase of walking?

METHODS: Walking kinematics of 14 non-disabled participants (25.2 years (SD 2.8)) were measured at self-selected speed. Rearfoot-shank and forefoot-rearfoot angles were measured from two models with two tracking methods: RFM, OFM, RFM-cluster, and OFM-cluster. In RFM-cluster and OFM-cluster, the rearfoot and forefoot tracking markers were rigidly clustered, fixed on rods’ tips attached to a metallic base. Statistical Parametric Mapping (SPM) One-Way Repeated Measures ANOVAs and SPM Paired t-tests were used to compare waveforms. Coefficients of Multiple Correlation (CMC) quantified the similarity between waveforms. One-way Repeated Measures ANOVAs were conducted to compare the ranges of motion (ROMs), and pre-planned contrasts investigated differences between the models and tracking methods. Intraclass Correlation Coefficients (ICC) were computed to verify the similarity between ROMs.

RESULTS: Differences occurred mostly in small parts of the stance phase for the cluster vs. non-cluster comparisons and the RFM vs. OFM comparisons. ROMs were slightly different between the models and tracking methods in most comparisons. The curves (CMC ≥ 0.71) were highly similar between the models and tracking methods. The ROMs (ICC ≥ 0.67) were moderatetly to highly similar in most comparisons. RFM vs. RFM-cluster (forefoot-rearfoot angle – transverse plane), OFM vs. OFM-cluster and RFM vs. OFM (forefoot-rearfoot angle – frontal plane) were not similar (non-significant).

SIGNIFICANCE: Rigid clusters are an alternative for tracking rearfoot-shank and forefoot-rearfoot angles during the stance phase of walking. However, specific differences should be considered to contrast results from different models and tracking methods.

PMID:34649170 | DOI:10.1016/j.gaitpost.2021.10.001