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Delgado-López PD, Montalvo-Afonso A, Martín-Alonso J, Martín-Velasco V, Diana-Martín R, Castilla-Díez JM. Predicting histological grade in symptomatic meningioma by an objective estimation of the tumoral surface irregularity. Neurocirugia (Astur : Engl Ed) 2024; 35:113-121. [PMID: 38244923 DOI: 10.1016/j.neucie.2023.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 10/03/2023] [Indexed: 01/22/2024]
Abstract
INTRODUCTION Predicting the histopathologic grade of meningioma is relevant because local recurrence is significantly greater in WHO grade II-III compared to WHO grade I tumours, which would ideally benefit from a more aggressive surgical strategy. It has been suggested that higher WHO grade tumours are more irregularly-shaped. However, irregularity is a subjective and observer-dependent feature. In this study, the tumour surface irregularity of a large series of meningiomas, measured upon preoperative MRI, is quantified and correlated with the WHO grade. METHODS Unicentric retrospective observational study of a cohort of symptomatic meningiomas surgically removed in the time period between January 2015 and December 2022. Using specific segmentation software, the Surface Factor (SF) was calculated for each meningioma. SF is an objective parameter that compares the surface of a sphere (minimum surface area for a given volume) with the same volume of the tumour against the actual surface of the tumour. This ratio varies from 0 to 1, being 1 the maximum sphericity. Since irregularly-shaped meningiomas present proportionally greater surface area, the SF tends to decrease as irregularity increases. SF was correlated with WHO grade and its predictive power was estimated with ROC curve analysis. RESULTS A total of 176 patients (64.7% females) were included in the study; 120 WHO grade I (71.9%), 43 WHO grade II (25.7%) and 4 WHO grade III (2.4%). A statistically significant difference was found between the mean SF of WHO grade I and WHO grade II-III tumours (0.8651 ± 0.049 versus 0.7081 ± 0.105, p < 0.0001). Globally, the SF correctly classified more than 90% of cases (area under ROC curve 0.940) with 93.3% sensibility and 80.9% specificity. A cutoff value of 0.79 yielded the maximum precision, with positive and negative predictive powers of 82.6% and 92.6%, respectively. Multivariate analysis yielded SF as an independent prognostic factor of WHO grade. CONCLUSION The Surface Factor is an objective and quantitative parameter that helps to identify aggressive meningiomas preoperatively. A cutoff value of 0.79 allowed differentiation between WHO grade I and WHO grade II-III with high precision.
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Affiliation(s)
| | | | | | | | - Rubén Diana-Martín
- Servicio de Neurocirugía, Hospital Universitario de Burgos, Burgos, Spain
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Kaiser KP, Wissiak E, Müller T, Daas L, El-Shabrawi Y, Ardjomand N. [Combined transepithelial PTK and topography-guided PRK for treatment of trauma-related corneal scarring]. Ophthalmologe 2021; 119:250-257. [PMID: 34432117 DOI: 10.1007/s00347-021-01480-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/19/2021] [Accepted: 07/22/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Corneal scars can severely impair visual performance and treatment can be challenging. The study aimed to evaluate a promising minimally invasive option in the treatment of corneal scars using transepithelial topography-guided ablation. METHODS This retrospective interventional study involved four eyes of four patients who developed corneal scarring and irregular surfaces due to trauma and were treated with topography-guided photorefractive keratectomy (TG-PRK) between 2017 and 2020. The ablation profile was calculated in all four cases using CRS-Master (Zeiss, Jena, Germany). The main outcome measures were uncorrected and best-corrected distance visual acuity, manifest refraction and corneal regularity by topographic images. The mean age was 34.75 ± 15.39 years and the follow-up time was 6 months for all patients. RESULTS In three cases full subjective refraction was corrected in one session and one patient had a refractive error of +0.5 D. Only corneal surface smoothing without additional refractive correction was performed in this case. All four patients showed improvement in uncorrected (2-3 Snellen lines) and corrected (3 Snellen lines) distance visual acuity. No complications occurred during or after the treatment and there was no reduction of visual acuity in any case. CONCLUSION The use of TG-PRK in patients with corneal scarring improves visual acuity in selected cases. In myopic patients most of the refractive error can also be corrected in a single session.
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Affiliation(s)
- Klemens Paul Kaiser
- Universitäts-Augenklinik, Medizinische Universität, Graz, Österreich.,Sehzentrum für Augenlaser & Augenchirurgie, Leechgasse 58, 8010, Graz, Österreich
| | - Elfriede Wissiak
- Universitäts-Augenklinik, Medizinische Universität, Graz, Österreich.,Sehzentrum für Augenlaser & Augenchirurgie, Leechgasse 58, 8010, Graz, Österreich
| | - Tom Müller
- Universitäts-Augenklinik, Medizinische Universität, Graz, Österreich.,Sehzentrum für Augenlaser & Augenchirurgie, Leechgasse 58, 8010, Graz, Österreich
| | - Loay Daas
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes, Homburg/Saar, Deutschland
| | - Yosuf El-Shabrawi
- Universitäts-Augenklinik, Medizinische Universität, Graz, Österreich
| | - Navid Ardjomand
- Universitäts-Augenklinik, Medizinische Universität, Graz, Österreich. .,Sehzentrum für Augenlaser & Augenchirurgie, Leechgasse 58, 8010, Graz, Österreich.
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Abstract
The present cross-sectional study aimed to assess the association of daily irregularity in energy intake and diet quality among apparently healthy adults in Iran. The research was conducted on 850 adult men and women (age range: 20-59 years) who attended health care centres in Tehran. Dietary intake was assessed by three, 24-h dietary recalls. Diet quality was assessed using the Dietary Approaches to Stop Hypertension (DASH) diet score and Healthy Eating Index-2015 (HEI-2015). An irregularity score of daily energy intake was calculated based on the deviation from the 3-d mean energy intake, with a higher score indicating more fluctuations in daily energy intake. Multiple linear regression analysis was used to assess the association of irregularity score of daily energy intake with food group intakes and DASH diet score and HEI-2015, controlling for age, sex, BMI, physical activity, education level and occupation status. The range of irregularity score was 0·55-133·3 (22·4 (sd 19·0)). Higher irregularity score of daily energy intake was significantly associated with a lower consumption of fruit, vegetables, legumes, low-fat dairy products and poultry, higher consumption of soft drinks, processed meat and nuts, and lower overall DASH diet score and HEI-2015. Overall, our findings showed that more day-to-day variations in energy intake may be correlated with a lower diet quality. More research is needed to confirm the associations observed in the present study and to clarify potential mechanisms explaining these associations.
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Bagheri H, Khanmohammadi R, Olyaei G, Talebian S, Reza Hadian M, Najafi M. Video game and motor-cognitive dual-task training could be suitable treatments to improve dual-task interference in older adults. Neurosci Lett 2021; 760:136099. [PMID: 34229042 DOI: 10.1016/j.neulet.2021.136099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 06/15/2021] [Accepted: 06/30/2021] [Indexed: 11/29/2022]
Abstract
The objective of study was to investigate the effects of video game training in comparison with traditional motor-cognitive dual-task training on dual-task interference in older adults. Sixty older adults were allocated to the video game (intervention group) or the motor-cognitive dual-task training (control group). The outcome measures were dual-task cost (DTC) of linear metrics (Standard deviation (SD) of amplitude and velocity) and DTC of nonlinear metrics (approximate entropy, Lyapunov and correlation dimension) acquired from postural sway time series from both the mediolateral (ML) and anteroposterior (AP) directions. The results revealed in both groups, dual-task cost of SD of amplitude and velocity as well as Lyapunov were significantly decreased in post-training and follow-up compared with pre-training (p < 0.017), while there was no significant difference between the groups. Video game and motor-cognitive dual-task training could be recommended as suitable treatments to improve dual-task interference.
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Affiliation(s)
- Hossein Bagheri
- Physical Therapy Department, Tehran University of Medical Sciences, Tehran, Iran
| | - Roya Khanmohammadi
- Physical Therapy Department, Tehran University of Medical Sciences, Tehran, Iran.
| | - Gholamreza Olyaei
- Physical Therapy Department, Tehran University of Medical Sciences, Tehran, Iran
| | - Saeed Talebian
- Physical Therapy Department, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Hadian
- Physical Therapy Department, Tehran University of Medical Sciences, Tehran, Iran
| | - Marziyeh Najafi
- Physical Therapy Department, Tehran University of Medical Sciences, Tehran, Iran
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Jamin A, Duval G, Annweiler C, Abraham P, Humeau-Heurtier A. Age-related alterations on the capacities to navigate on a bike: use of a simulator and entropy measures. Med Biol Eng Comput 2020; 59:13-22. [PMID: 33185831 DOI: 10.1007/s11517-020-02257-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 08/29/2020] [Indexed: 11/26/2022]
Abstract
Studying the impact of age is important to understand the phenomenon of aging and the disorders that are associated with it. In this work, we analyze age-related alterations on the capacities to navigate on a bike. For this purpose, we use CycléoONE, a bike simulator, and entropy measures. We thus record navigation data (handlebar angle and speed) during the ride. They are processed with two cross-distribution entropy methods (time-shift multiscale cross-distribution entropy and multiscale cross-distribution entropy). We also analyze the time series with a detrended cross-correlation analysis to determine which method can best underline age-related alterations. Our results show that methods based on cross-distribution entropy may be efficient to stress the decrease in navigation capacities with age. The results are very encouraging for our future goal of adding medical benefits to a leisure equipment. They also show the value of using virtual reality to study the impact of age. Graphical Abstract This study deals with the use of the signal processing methods (multiscale cross-entropy and multiscale cross-correlation) applied on naviagtion data, acquired with a bike simulator, to study the impact of age on two populations (young healthy subjects and older adults with loss of autonomy).
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Affiliation(s)
- Antoine Jamin
- COTTOS Médical, Allée du 9 novembre 1989, 49240, Avrillé, France.
- LARIS - Laboratoire Angevin de Recherche en Ingénierie des Systèmes, University of Angers, 62 avenue Notre-Dame du Lac, 49000, Angers, France.
| | - Guillaume Duval
- Department of Geriatric Medicine, Angers University Hospital, 4 rue du Larrey, 49933 cedex 9, Angers, France
- Angers University Memory Clinic, Research Center on Autonomy and Longevity, UPRES EA 4638, University of Angers, 4 rue du Larrey, 49933 cedex 9, Angers, France
| | - Cédric Annweiler
- Department of Geriatric Medicine, Angers University Hospital, 4 rue du Larrey, 49933 cedex 9, Angers, France
- Angers University Memory Clinic, Research Center on Autonomy and Longevity, UPRES EA 4638, University of Angers, 4 rue du Larrey, 49933 cedex 9, Angers, France
- Robarts Research Institute, Department of Medical Biophysics, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
| | - Pierre Abraham
- Sports Medicine Department, UMR Mitovasc CNRS 6015 INSERM 1228, Angers University Hospital, 4 rue du Larrey, 49933, Angers, France
| | - Anne Humeau-Heurtier
- LARIS - Laboratoire Angevin de Recherche en Ingénierie des Systèmes, University of Angers, 62 avenue Notre-Dame du Lac, 49000, Angers, France
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Juchler N, Schilling S, Bijlenga P, Morel S, Rüfenacht D, Kurtcuoglu V, Hirsch S. Shape irregularity of the intracranial aneurysm lumen exhibits diagnostic value. Acta Neurochir (Wien) 2020; 162:2261-2270. [PMID: 32500254 DOI: 10.1007/s00701-020-04428-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/22/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND Morphological irregularity is linked to intracranial aneurysm wall instability and manifests in the lumen shape. Yet there is currently no consent on how to assess shape irregularity. The aims of this work are to quantify irregularity as perceived by clinicians, to break down irregularity into morphological attributes, and to relate these to clinically relevant factors such as rupture status, aneurysm location, and patient age or sex. METHODS Thirteen clinicians and 26 laypersons assessed 134 aneurysm lumen segmentations in terms of overall perceived irregularity and five different morphological attributes (presence/absence of a rough surface, blebs, lobules, asymmetry, complex geometry of the parent vasculature). We examined rater agreement and compared the ratings with clinical factors by means of regression analysis or binary classification. RESULTS Using rank-based aggregation, the irregularity ratings of clinicians and laypersons did not differ statistically. Perceived irregularity showed good agreement with curvature (coefficient of determination R2 = 0.68 ± 0.08) and was modeled very accurately using the five morphological rating attributes plus shape elongation (R2 = 0.95 ± 0.02). In agreement with previous studies, irregularity was associated with aneurysm rupture status (AUC = 0.81 ± 0.08); adding aneurysm location as an explanatory variable increased the AUC to 0.87 ± 0.09. Besides irregularity, perceived asymmetry, presence of blebs or lobules, aneurysm size, non-sphericity, and curvature were linked to rupture. No association was found between morphology and any of patient sex, age, and history of smoking or hypertension. Aneurysm size was linked to morphology. CONCLUSIONS Irregular lumen shape carries significant information on the aneurysm's disease status. Irregularity constitutes a continuous parameter that shows a strong association with the rupture status. To improve the objectivity of morphological assessment, we suggest examining shape through six different morphological attributes, which can characterize irregularity accurately.
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Affiliation(s)
- Norman Juchler
- Institute of Applied Simulation, Zurich University of Applied Sciences, Wädenswil, Switzerland.
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland.
| | - Sabine Schilling
- Institute of Applied Simulation, Zurich University of Applied Sciences, Wädenswil, Switzerland
- Institute of Tourism ITW, Lucerne University of Applied Sciences and Arts, Lucerne, Switzerland
| | - Philippe Bijlenga
- Neurosurgery Division, Department of Clinical Neurosciences, Geneva University Hospital and Faculty of Medicine, Geneva, Switzerland
| | - Sandrine Morel
- Neurosurgery Division, Department of Clinical Neurosciences, Geneva University Hospital and Faculty of Medicine, Geneva, Switzerland
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | | | - Vartan Kurtcuoglu
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
- National Center of Competence in Research, Kidney.CH, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Sven Hirsch
- Institute of Applied Simulation, Zurich University of Applied Sciences, Wädenswil, Switzerland.
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Helakari H, Kananen J, Huotari N, Raitamaa L, Tuovinen T, Borchardt V, Rasila A, Raatikainen V, Starck T, Hautaniemi T, Myllylä T, Tervonen O, Rytky S, Keinänen T, Korhonen V, Kiviniemi V, Ansakorpi H. Spectral entropy indicates electrophysiological and hemodynamic changes in drug-resistant epilepsy - A multimodal MREG study. Neuroimage Clin 2019; 22:101763. [PMID: 30927607 DOI: 10.1016/j.nicl.2019.101763] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 02/01/2019] [Accepted: 03/10/2019] [Indexed: 12/20/2022]
Abstract
Objective Epilepsy causes measurable irregularity over a range of brain signal frequencies, as well as autonomic nervous system functions that modulate heart and respiratory rate variability. Imaging dynamic neuronal signals utilizing simultaneously acquired ultra-fast 10 Hz magnetic resonance encephalography (MREG), direct current electroencephalography (DC-EEG), and near-infrared spectroscopy (NIRS) can provide a more comprehensive picture of human brain function. Spectral entropy (SE) is a nonlinear method to summarize signal power irregularity over measured frequencies. SE was used as a joint measure to study whether spectral signal irregularity over a range of brain signal frequencies based on synchronous multimodal brain signals could provide new insights in the neural underpinnings of epileptiform activity. Methods Ten patients with focal drug-resistant epilepsy (DRE) and ten healthy controls (HC) were scanned with 10 Hz MREG sequence in combination with EEG, NIRS (measuring oxygenated, deoxygenated, and total hemoglobin: HbO, Hb, and HbT, respectively), and cardiorespiratory signals. After pre-processing, voxelwise SEMREG was estimated from MREG data. Different neurophysiological and physiological subfrequency band signals were further estimated from MREG, DC-EEG, and NIRS: fullband (0–5 Hz, FB), near FB (0.08–5 Hz, NFB), brain pulsations in very-low (0.009–0.08 Hz, VLFP), respiratory (0.12–0.4 Hz, RFP), and cardiac (0.7–1.6 Hz, CFP) frequency bands. Global dynamic fluctuations in MREG and NIRS were analyzed in windows of 2 min with 50% overlap. Results Right thalamus, cingulate gyrus, inferior frontal gyrus, and frontal pole showed significantly higher SEMREG in DRE patients compared to HC. In DRE patients, SE of cortical Hb was significantly reduced in FB (p = .045), NFB (p = .017), and CFP (p = .038), while both HbO and HbT were significantly reduced in RFP (p = .038, p = .045, respectively). Dynamic SE of HbT was reduced in DRE patients in RFP during minutes 2 to 6. Fitting to the frontal MREG and NIRS results, DRE patients showed a significant increase in SEEEG in FB in fronto-central and parieto-occipital regions, in VLFP in parieto-central region, accompanied with a significant decrease in RFP in frontal pole and parietal and occipital (O2, Oz) regions. Conclusion This is the first study to show altered spectral entropy from synchronous MREG, EEG, and NIRS in DRE patients. Higher SEMREG in DRE patients in anterior cingulate gyrus together with SEEEG and SENIRS results in 0.12–0.4 Hz can be linked to altered parasympathetic function and respiratory pulsations in the brain. Higher SEMREG in thalamus in DRE patients is connected to disturbances in anatomical and functional connections in epilepsy. Findings suggest that spectral irregularity of both electrophysiological and hemodynamic signals are altered in specific way depending on the physiological frequency range. Simultaneous imaging methods indicate spectral irregularity in neurovascular and electrophysiological brain pulsations in DRE. Altered spectral entropy in EEG, NIRS and BOLD indicate dysfunctional brain pulsations in respiratory frequency in epilepsy. Spectral irregularity (0-5 Hz) of BOLD in right thalamus supports previous structural and functional findings in epilepsy.
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Singer AB, Whitworth KW, Haug LS, Sabaredzovic A, Impinen A, Papadopoulou E, Longnecker MP. Menstrual cycle characteristics as determinants of plasma concentrations of perfluoroalkyl substances (PFASs) in the Norwegian Mother and Child Cohort (MoBa study). Environ Res 2018; 166:78-85. [PMID: 29879567 PMCID: PMC6174531 DOI: 10.1016/j.envres.2018.05.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 04/20/2018] [Accepted: 05/16/2018] [Indexed: 05/20/2023]
Abstract
INTRODUCTION Perfluoroalkyl substances (PFASs) are fluorinated organic compounds that have been used in a variety of industrial and consumer applications. Menstruation is implicated as a possible route of elimination for PFASs in women. The overall purpose of this study was to examine menstrual cycle characteristics as determinants of plasma PFAS concentrations in women. METHODS Our study sample consisted of 1977 pregnant women from the Norwegian Mother and Child Cohort (MoBa) study. The women were asked about menstrual cycle regularity in the year before the pregnancy and typical menstrual cycle length as well as other demographic and reproductive characteristics in a questionnaire completed during the pregnancy. Blood samples were collected around 17-18 weeks gestation and PFAS concentrations were measured in plasma. We examined the association between menstrual cycle characteristics and seven PFASs (perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorohexane sulfonate (PFHxS), perfluoroheptane sulfonate (PFHpS), and perfluorooctane sulfonate (PFOS)) using multiple linear regression, adjusted for age, pre-pregnancy body mass index, smoking, education, income, parity, oral contraceptive use, inter-pregnancy interval, and breastfeeding duration. RESULTS Irregular cycles were not associated with PFAS concentrations. Overall, we found no evidence of associations between menstrual cycle length and PFAS concentrations. In subgroup analyses we found some evidence, among parous women, of decreased PFHpS and PFOS with short menstrual cycles; we also found, among recent OC users (in the 12 months before the questionnaire) increased PFNA and PFUnDA with long cycle length. Limitations of our study include misclassification of menstrual cycle characteristics, small sample sizes in the sub-group analyses, and a lack of information on duration and volume of menses. CONCLUSIONS In the entire study sample, we found little evidence of menstrual cycle characteristics as determinants of PFAS concentrations. However, we observed some associations between cycle length and PFAS concentrations with some select PFAS compounds in subgroup analyses.
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Affiliation(s)
- Alison B Singer
- The Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA.
| | - Kristina W Whitworth
- Department of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston, School of Public Health in San Antonio, San Antonio, TX, USA; Southwest Center for Occupational and Environmental Health, The University of Texas Health Science Center at Houston, School of Public Health, Houston, TX, USA
| | - Line S Haug
- Department of Environmental Exposures and Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
| | - Azemira Sabaredzovic
- Department of Environmental Exposures and Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
| | - Antti Impinen
- Department of Toxicology and Risk Assessment, Norwegian Institute of Public Health, Oslo, Norway
| | - Eleni Papadopoulou
- Department of Environmental Exposures and Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
| | - Matthew P Longnecker
- National Institute for Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Durham, NC, USA
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Affiliation(s)
- Angelo Cuzalina
- Cosmetic Surgery Fellowship Program, AACS, 7322 East 91st, Tulsa, OK 74133, USA.
| | - Andre V Guerrero
- Inland Institute, 1333 East Foothill Boulevard Suite 1, Upland, CA 91786, USA; Department of Oral and Maxillofacial Surgery, Loma Linda University, 11092 Anderson Street, Loma Linda, CA 92350, USA
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Fermín LJ, Lévy-Véhel J. Variability and singularity arising from poor compliance in a pharmacokinetic model II: the multi-oral case. J Math Biol 2017; 74:809-41. [PMID: 27431876 DOI: 10.1007/s00285-016-1041-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 07/04/2016] [Indexed: 10/21/2022]
Abstract
We propose a stochastic model for the drug concentration in the case of multiple oral doses and in a situation of poor patient adherence. Our model is able to take into account an irregular drug intake schedule. This article is the second in a series of three. It presents a multi-oral version of the results given in Lévy-Véhel and Lévy-Véhel (J Pharmacokinet Pharmacodyn 40(1):15-39, 2013), that dealt with the multi-IV bolus case. Under the assumption that the irregular dosing schedule follows a Poisson law, we study features of the drug concentration that have practical implications, such as its variability and the regularity of its cumulative probability distribution, which describes its predictive power with respect to the mean behaviour. We consider four variants: continuous-time, with either deterministic or random doses, and discrete-time, also with either deterministic or random doses. Our computations allow one to assess in a precise way the effect of various significant parameters such as the mean rate of intake, the elimination rate, the absorption rate and the mean dose. They quantify how much poor adherence will affect the efficacy of therapy. To appreciate this impact, we provide detailed comparisons with the variability of concentration in two reference situations: a fully adherent patient and a population of fully adherent patients with log-normally distributed pharmacokinetic parameters. Besides, the discrete-time versions of our models reveal unexpected links with objects which have been studied in the mathematical literature under the name of infinite Bernoulli convolutions (Erdós, Am J Math 61:974-975, 1939). This allows us to quantify the fact that, when the random dosing schedule is too sparse, the concentration behaves in a very erratic way. Our results complement the ones in Lévy-Véhel and Lévy-Véhel (J Pharmacokinet Pharmacodyn 40(1):15-39, 2013) and help understanding the consequences of poor adherence. They may have practical outcomes in terms of drug dosing and scheduling.
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Corino VD, Sandberg F, Mainardi LT, Platonov PG, Sörnmo L. Noninvasive characterization of atrioventricular conduction in patients with atrial fibrillation. J Electrocardiol 2015; 48:938-42. [PMID: 26324177 DOI: 10.1016/j.jelectrocard.2015.08.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Indexed: 11/20/2022]
Abstract
The atrioventricular (AV) node plays a fundamental role in patients with atrial fibrillation (AF), acting as a filter to the numerous irregular atrial impulses which bombard the node. A phenomenological approach to better understand AV nodal electrophysiology is to analyze the ventricular response with respect to irregularity. In different cohorts of AF patients, such analysis has been performed with the aim to evaluate the association between ventricular response characteristics and long-term clinical outcome and to determine whether irregularity is affected by rate-control drugs. Another approach to studying AV nodal characteristics is to employ a mathematical model which accounts for the refractory periods of the two AV nodal pathways. With atrial fibrillatory rate and RR intervals as input, the model has been considered for analyzing data during (i) rest and head-up tilt test, (ii) tecadenoson and esmolol, and (iii) rate-control drugs. The present paper provides an overview of our recent work on the characterization and assessment of AV nodal conduction using these two approaches.
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