177 results on '"Williamson JM"'
Search Results
2. Hypoplastic anaemia and hydroflumethiazide
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Neilson Fj, Gibbs Wn, and Williamson Jm
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Adult ,Pediatrics ,medicine.medical_specialty ,Hydroflumethiazide ,business.industry ,Anemia, Aplastic ,Hypoplastic anaemia ,General Medicine ,medicine ,Humans ,Female ,business ,medicine.drug - Published
- 1966
3. Protease inhibitors and cardiovascular outcomes in patients with HIV-1.
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Holmberg SD, Moorman AC, Williamson JM, Tong TC, Ward DJ, Wood KC, Greenberg AE, Janssen RS, and HIV Outpatient Study (HOPS) Investigators
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- 2002
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4. Metastable atom and electron density diagnostic in the initial stage of a pulsed discharge in Ar and other rare gases by emission spectroscopy
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Williamson, JM
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- 2012
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5. Short DC Discharge with Wall Probe as a Gas Analytical Detector
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Williamson, JM
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- 2010
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6. Genetically edited human placental organoids cast new light on the role of ACE2.
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Arthurs AL, Dietrich B, Knöfler M, Lushington CJ, Thomas PQ, Adikusuma F, Williamson JM, Babikha S, Damhuis T, Jankovic-Karasoulos T, Smith MD, Pringle KG, and Roberts CT
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- Humans, Female, Pregnancy, Gene Editing methods, Peptidyl-Dipeptidase A genetics, Peptidyl-Dipeptidase A metabolism, Genotype, Angiotensin-Converting Enzyme 2 metabolism, Angiotensin-Converting Enzyme 2 genetics, Organoids metabolism, Placenta metabolism
- Abstract
ACE2 expression is altered in pregnancy disorders and ACE2 gene variants are associated with several major pregnancy complications including small-for-gestational-age, fetal growth restriction and preeclampsia. This study utilised gene-editing to generate both ACE2 knockout and ACE2 rs2074192 placental organoids, facilitating mechanistic studies into the role of ACE2 in placental development, and the effect of fetal carriage of ACE2 rs2074192 CC, CT and TT genotypes. Parameters of cell and organoid growth were measured, together with qPCR, Western Blotting, and ELISA assessments, in all groups from both organoid models. Here, we report that ACE2 knockout results in delayed placental cell growth and increased cell death. ACE2 knockout organoids had lower ACE protein expression, reduced organoid diameters and asymmetrical growth. Placental organoids with the ACE2 rs2074192 TT genotype had significantly higher expression of ACE2 mRNA and ACE2 protein with elevated ACE2:ACE expression ratio and no change in ACE protein. Despite increased expression of ACE2 protein, ACE2 enzyme activity was significantly decreased in ACE2 rs2074192 TT placental organoids. TT organoids also had reduced diameters and asymmetrical growth. Our research provides a new molecular understanding of the role of ACE2 in placental development, with potential implications for pregnancy in the carriage of the ACE2 rs2074192 gene variant., Competing Interests: Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)
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- 2025
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7. Fundamental Insights into Copper-Epoxy Interfaces for High-Frequency Chip-to-Chip Interconnects.
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Park J, Dauda M, Bello M, Agbadan I, Engler AC, Williamson JM, Mathew V, Park S, and Flake JC
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Future processes and materials are needed to enable multichip packages with chip-to-chip (C2C) data rates of 50 GB/s or higher. This presents a fundamental challenge because of the skin effect, which exacerbates signal transmission losses at high frequencies. Our results indicate that smooth copper interconnects with relatively thin cuprous oxides (Cu
2 O, CuI ) and amine-functional silane adhesion promoters improve interfacial adhesion with epoxy dielectrics by nearly an order of magnitude. For the first time, we present X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy evidence of Cu(I)-O-Si bond formation at silane-treated interfaces. Thus, relatively smooth interconnects can benefit from reduced skin losses while maintaining their mechanical integrity and reliability. Failure mechanisms of Cu interconnects with cuprous and cupric oxide (CuO, CuII ) are explored using scanning electron microscopy (SEM) and Auger electron spectroscopy (AES). These results indicate that both cupric oxides and relatively thick cuprous oxide interfaces lead to relatively weaker interfaces compared with thin cuprous oxides with adhesion promoters.- Published
- 2025
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8. Mitral Leaflet Separation Revisited: A Surrogate of Mitral Valve Area in Young People With Rheumatic Mitral Regurgitation Living in Remote Areas.
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Williamson JM, Remenyi B, Horton AE, Morris P, and Whalley GA
- Abstract
Competing Interests: Conflicts of Interest None.
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- 2025
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9. Using Location-Based Services Data to Map and Evaluate a Community Design Intervention to Increase Bicycling, Denver, Colorado.
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Park YS, King RJ, Pejavara A, Hathaway K, Wergin J, Townley C, Leonard S, Williamson JM, Galuska DA, and Fulton JE
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- 2024
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10. Elevated Trans-mitral Pressure Gradient Predicts Surgery in Young People with Moderate-Severe Rheumatic Mitral Regurgitation.
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Williamson JM, Whalley GA, Horton AE, Morris P, and Remenyi B
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Mitral regurgitation (MR) is the most common lesion in children with rheumatic heart disease (RHD). Progression of RHD results in the need for surgical intervention, the timing of which is dictated by left ventricular dilatation and the onset of heart failure symptoms. We sought to determine whether elevation in trans-mitral pressure gradient (TMPG) in those with moderate or severe rheumatic MR without significant mitral stenosis (MS) could predict the need for future surgical intervention. Echocardiographic studies were reviewed for 116 children and young people with moderate or severe rheumatic MR. Those with significant mitral stenosis or concurrent aortic valve disease were excluded. Trans-mitral pressure gradient was measured at baseline and details of mitral valve surgical intervention were retrieved from a registry database. Time to future surgery (up to six years) was compared between those with TMPG < 5 mmHg and TMPG ≥ 5 mmHg. Survival curves demonstrated an increased risk of surgery for those with TMPG ≥ 5 mmHg with Cox proportional regression analysis providing a hazard ratio of 5.8. The proportion free from mitral valve surgery at one year for the TMPG < 5 mmHg group was 0.94 (95% CI 0.86-0.97), compared to 0.62 (95% CI 0.42-0.77) in the ≥ 5 mmHg group. Trans-mitral pressure gradient is a strong predictor of future mitral valve surgery in children and young people with significant rheumatic MR without MS. This non-invasive measure could be used to signal the need for more aggressive monitoring in order to optimize the timing of intervention., (© 2024. The Author(s).)
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- 2024
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11. Factors influencing RNA yield from placenta tissue.
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Arthurs AL, McCullough D, Williamson JM, Jankovic-Karasoulos T, Smith MD, and Roberts CT
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- Humans, Pregnancy, Female, Animals, Mice, Decidua, HEK293 Cells, Chorion, Placenta, RNA
- Abstract
High yield and integrity of placental RNA are crucial for placental transcriptomics studies. We assessed the effects of time to placental collection post-delivery; tissue storage, amount and method used for extraction; mode of delivery; and tissue type on total RNA yield. The optimal protocol for RNA extraction from placental tissue includes cryofreezing of the sample upon collection and RNA extraction from 50 mg of tissue using TRIzol reagent. Decidua yielded highest RNA quantity/mg of tissue, followed by villous tissue and the chorion. Comparisons with murine kidney and HEK293T show lower placental RNA yield, likely due to highly dense and heterogeneous tissue make-up and potential high placental nuclease activity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2023
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12. Drug-Inducible Gene Therapy Effectively Reduces Spontaneous Seizures in Kindled Rats but Creates Off-Target Side Effects in Inhibitory Neurons.
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Sullivan KA, Vitko I, Blair K, Gaykema RP, Failor MJ, San Pietro JM, Dey D, Williamson JM, Stornetta RL, Kapur J, and Perez-Reyes E
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- Rats, Male, Animals, Doxycycline pharmacology, Neurons metabolism, Hippocampus metabolism, Genetic Therapy, Disease Models, Animal, Epilepsy metabolism, Epilepsy, Temporal Lobe metabolism, Drug-Related Side Effects and Adverse Reactions metabolism
- Abstract
Over a third of patients with temporal lobe epilepsy (TLE) are not effectively treated with current anti-seizure drugs, spurring the development of gene therapies. The injection of adeno-associated viral vectors (AAV) into the brain has been shown to be a safe and viable approach. However, to date, AAV expression of therapeutic genes has not been regulated. Moreover, a common property of antiepileptic drugs is a narrow therapeutic window between seizure control and side effects. Therefore, a long-term goal is to develop drug-inducible gene therapies that can be regulated by clinically relevant drugs. In this study, a first-generation doxycycline-regulated gene therapy that delivered an engineered version of the leak potassium channel Kcnk2 (TREK-M) was injected into the hippocampus of male rats. Rats were electrically stimulated until kindled. EEG was monitored 24/7. Electrical kindling revealed an important side effect, as even low expression of TREK M in the absence of doxycycline was sufficient to cause rats to develop spontaneous recurring seizures. Treating the epileptic rats with doxycycline successfully reduced spontaneous seizures. Localization studies of infected neurons suggest seizures were caused by expression in GABAergic inhibitory neurons. In contrast, doxycycline increased the expression of TREK-M in excitatory neurons, thereby reducing seizures through net inhibition of firing. These studies demonstrate that drug-inducible gene therapies are effective in reducing spontaneous seizures and highlight the importance of testing for side effects with pro-epileptic stressors such as electrical kindling. These studies also show the importance of evaluating the location and spread of AAV-based gene therapies in preclinical studies.
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- 2023
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13. Sensitivity and Uncertainty Analysis for Two-stream Capture-Recapture Methods in Disease Surveillance.
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Zhang Y, Chen J, Ge L, Williamson JM, Waller LA, and Lyles RH
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- Humans, Computer Simulation, Uncertainty
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Capture-recapture methods are widely applied in estimating the number ( ) of prevalent or cumulatively incident cases in disease surveillance. Here, we focus the bulk of our attention on the common case in which there are 2 data streams. We propose a sensitivity and uncertainty analysis framework grounded in multinomial distribution-based maximum likelihood, hinging on a key dependence parameter that is typically nonidentifiable but is epidemiologically interpretable. Focusing on the epidemiologically meaningful parameter unlocks appealing data visualizations for sensitivity analysis and provides an intuitively accessible framework for uncertainty analysis designed to leverage the practicing epidemiologist's understanding of the implementation of the surveillance streams as the basis for assumptions driving estimation of . By illustrating the proposed sensitivity analysis using publicly available HIV surveillance data, we emphasize both the need to admit the lack of information in the observed data and the appeal of incorporating expert opinion about the key dependence parameter. The proposed uncertainty analysis is a simulation-based approach designed to more realistically acknowledge variability in the estimated associated with uncertainty in an expert's opinion about the nonidentifiable parameter, together with the statistical uncertainty. We demonstrate how such an approach can also facilitate an appealing general interval estimation procedure to accompany capture-recapture methods. Simulation studies illustrate the reliable performance of the proposed approach for quantifying uncertainties in estimating in various contexts. Finally, we demonstrate how the recommended paradigm has the potential to be directly extended for application to data from >2 surveillance streams., Competing Interests: Disclosure: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)
- Published
- 2023
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14. A censored quantile regression approach for relative survival analysis: Relative survival quantile regression.
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Williamson JM, Lin HM, and Lyles RH
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- Humans, Computer Simulation, Regression Analysis, Survival Analysis, Models, Statistical
- Abstract
We propose a censored quantile regression model for the analysis of relative survival data. We create a hybrid data set consisting of the study observations and counterpart randomly sampled pseudopopulation observations imputed from population life tables that adjust for expected mortality. We then fit a censored quantile regression model to the hybrid data incorporating demographic variables (e.g., age, biologic sex, calendar time) corresponding to the population life tables of demographically-similar individuals, a population versus study covariate, and its interactions with the variables of interest. These latter variables can be interpreted as relative survival parameters that depict the differences in failure quantiles between the study participants and their population counterparts., (© 2023 Wiley-VCH GmbH.)
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- 2023
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15. Achalasia: investigation and management.
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Slim N and Williamson JM
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- Humans, Esophageal Sphincter, Lower surgery, Manometry adverse effects, Manometry methods, Esophagoscopy methods, Esophageal Achalasia diagnosis, Esophageal Achalasia therapy, Deglutition Disorders diagnosis, Deglutition Disorders etiology, Deglutition Disorders therapy
- Abstract
Achalasia, characterised by the absence of peristalsis and failure of relaxation of the lower oesophageal sphincter, is an uncommon degenerative condition that results in dysphagia. If left untreated it can lead to aspiration, oesophageal perforation, oesophagitis and malnutrition. It has a range of immune, allergic, viral and genetic aetiological causes. Successful diagnosis relies on the use of oesophagogastroduodenoscopy, barium swallow and oesophageal manometry to characterise the severity of the disease and to rule out underlying malignancy. Although no treatment can reverse the degenerative process, therapeutic strategies including lifestyle modification, medication, endoscopic and operative intervention can help to reduce symptoms. This article reviews the latest methods used to investigate and manage achalasia.
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- 2023
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16. Applying the RIME Framework to Level Nurse Practitioner Curriculum Competencies.
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Johnson HL, Beatty JR, Archer HR, Best NI, Trautmann JL, Williams JK, Williamson JM, Seibert DC, and Taylor LA
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- Humans, Nursing Education Research, Curriculum, Nurse Practitioners
- Abstract
Background: Nurse practitioner (NP) faculty assess student acquisition of knowledge through examinations, simulation, and clinical performance., Problem: Developing appropriately leveled curriculum, assessments, and clinical expectations that accurately capture student maturation presents a challenge., Approach: The Reporter, Interpreter, Manager, Educator (RIME) provided the framework for doctor of nursing practice NP curriculum redesign to enhance student performance and content mastery. Faculty used a gap analysis approach, iteratively leveling specialty content, course competencies, examination questions, simulation cases, and clinical expectations using the building blocks of RIME., Outcomes: Objective scores on student evaluations for clinical courses exceeded the threshold established, including 83% of simulation encounters. Faculty implemented targeted methods to remediate areas of underperformance., Conclusions: Structuring the course competencies and preceptor feedback around RIME made it easier to pinpoint specific deficiencies and target remediation. It also helped guide discussions about the minimum acceptable standard for student performance., Competing Interests: The authors declare no conflicts of interest, nor financial relationships to report., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)
- Published
- 2023
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17. High Folate, Perturbed One-Carbon Metabolism and Gestational Diabetes Mellitus.
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Williamson JM, Arthurs AL, Smith MD, Roberts CT, and Jankovic-Karasoulos T
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- 5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase metabolism, Animals, Betaine, Carbon metabolism, Choline, Female, Folic Acid metabolism, Homocysteine, Humans, Methylenetetrahydrofolate Reductase (NADPH2) metabolism, Micronutrients, Pregnancy, Thymidylate Synthase, Vitamin B 12, Diabetes, Gestational, Neural Tube Defects
- Abstract
Folate is a dietary micronutrient essential to one-carbon metabolism. The World Health Organisation recommends folic acid (FA) supplementation pre-conception and in early pregnancy to reduce the risk of fetal neural tube defects (NTDs). Subsequently, many countries (~92) have mandatory FA fortification policies, as well as recommendations for periconceptional FA supplementation. Mandatory fortification initiatives have been largely successful in reducing the incidence of NTDs. However, humans have limited capacity to incorporate FA into the one-carbon metabolic pathway, resulting in the increasingly ubiquitous presence of circulating unmetabolised folic acid (uFA). Excess FA intake has emerged as a risk factor in gestational diabetes mellitus (GDM). Several other one-carbon metabolism components (vitamin B12, homocysteine and choline-derived betaine) are also closely entwined with GDM risk, suggesting a role for one-carbon metabolism in GDM pathogenesis. There is growing evidence from in vitro and animal studies suggesting a role for excess FA in dysregulation of one-carbon metabolism. Specifically, high levels of FA reduce methylenetetrahydrofolate reductase (MTHFR) activity, dysregulate the balance of thymidylate synthase (TS) and methionine synthase (MTR) activity, and elevate homocysteine. High homocysteine is associated with increased oxidative stress and trophoblast apoptosis and reduced human chorionic gonadotrophin (hCG) secretion and pancreatic β-cell function. While the relationship between high FA, perturbed one-carbon metabolism and GDM pathogenesis is not yet fully understood, here we summarise the current state of knowledge. Given rising rates of GDM, now estimated to be 14% globally, and widespread FA food fortification, further research is urgently needed to elucidate the mechanisms which underpin GDM pathogenesis.
- Published
- 2022
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18. New oligodendrocytes exhibit more abundant and accurate myelin regeneration than those that survive demyelination.
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Neely SA, Williamson JM, Klingseisen A, Zoupi L, Early JJ, Williams A, and Lyons DA
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- Animals, Myelin Sheath physiology, Oligodendroglia physiology, Regeneration, Zebrafish, Demyelinating Diseases pathology, Multiple Sclerosis pathology
- Abstract
Oligodendrocytes that survive demyelination can remyelinate, including in multiple sclerosis (MS), but how they do so is unclear. In this study, using zebrafish, we found that surviving oligodendrocytes make few new sheaths and frequently mistarget new myelin to neuronal cell bodies, a pathology we also found in MS. In contrast, oligodendrocytes generated after demyelination make abundant and correctly targeted sheaths, indicating that they likely also have a better regenerative potential in MS., (© 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.)
- Published
- 2022
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19. Myelination induces axonal hotspots of synaptic vesicle fusion that promote sheath growth.
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Almeida RG, Williamson JM, Madden ME, Early JJ, Voas MG, Talbot WS, Bianco IH, and Lyons DA
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- Animals, Axons physiology, Myelin Sheath physiology, Oligodendroglia, Synaptic Vesicles, Zebrafish physiology
- Abstract
Myelination of axons by oligodendrocytes enables fast saltatory conduction. Oligodendrocytes are responsive to neuronal activity, which has been shown to induce changes to myelin sheaths, potentially to optimize conduction and neural circuit function. However, the cellular bases of activity-regulated myelination in vivo are unclear, partly due to the difficulty of analyzing individual myelinated axons over time. Activity-regulated myelination occurs in specific neuronal subtypes and can be mediated by synaptic vesicle fusion, but several questions remain: it is unclear whether vesicular fusion occurs stochastically along axons or in discrete hotspots during myelination and whether vesicular fusion regulates myelin targeting, formation, and/or growth. It is also unclear why some neurons, but not others, exhibit activity-regulated myelination. Here, we imaged synaptic vesicle fusion in individual neurons in living zebrafish and documented robust vesicular fusion along axons during myelination. Surprisingly, we found that axonal vesicular fusion increased upon and required myelination. We found that axonal vesicular fusion was enriched in hotspots, namely the heminodal non-myelinated domains into which sheaths grew. Blocking vesicular fusion reduced the stable formation and growth of myelin sheaths, and chemogenetically stimulating neuronal activity promoted sheath growth. Finally, we observed high levels of axonal vesicular fusion only in neuronal subtypes that exhibit activity-regulated myelination. Our results identify a novel "feedforward" mechanism whereby the process of myelination promotes the neuronal activity-regulated signal, vesicular fusion that, in turn, consolidates sheath growth along specific axons selected for myelination., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
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20. Reduction in Newborn Screening False Positive Results Following a New Collection Protocol: a Quality Improvement Project.
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Kamleh M, Williamson JM, Casas K, and Mohamed M
- Abstract
Objective: Premature infants are known to have a higher rate of false positive newborn screening (NBS) results, with TPN as a contributing factor. The purpose of this quality improvement (QI) project is to reduce false positive NBS results via a TPN interruption protocol., Methods: A multidisciplinary team reviewed the literature and developed a new NBS collection protocol, which was implemented in 2 periods. In period 1, TPN was interrupted for 4 hours before NBS sample collection and initiation of carnitine supplements was avoided. In period 2, TPN was interrupted for 6 hours for infants birth weight (BW) < 1000 g, carnitine supplementation continued to be avoided. The rates of false positives NBS results were compared pre- and post-interventions in periods 1 and 2., Results: Four hundred twelve neonates were evaluated prior to implementation of this QI project (July 2013-June 2014) and 414 during period 1 intervention (July 2014-June 2016). False positive results decreased from 20.6% to 11.4% (p < 0.001) among all BW categories following the 4-hour TPN interruption. The rate of false positives was further reduced among infants < 1000 g (p = 0.035) in period 2 (n = 112), including a significant reduction in false positive results with elevated amino acid profiles (p = 0.005)., Conclusions: The implementation of a strict NBS collection protocol reduced false positive NBS results, which potentially can improve patient care by reducing unnecessary laboratory draws, pain, and parental anxiety. Interruption of TPN for 6 hours was significant in reducing NBS false positive results in neonates < 1000 g., Competing Interests: Disclosures. The authors declare no conflicts or financial interest in any product or service mentioned in the manuscript, including grants, equipment, medications, employment, gifts, and honoraria. The authors had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis., (Copyright. Pediatric Pharmacy Association. All rights reserved. For permissions, email: mhelms@pediatricpharmacy.org 2021.)
- Published
- 2021
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21. Neocortical injury-induced status epilepticus.
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Singh T, Joshi S, Williamson JM, and Kapur J
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- Animals, Cobalt toxicity, Disease Models, Animal, Dose-Response Relationship, Drug, Electroencephalography, Female, Homocysteine toxicity, Magnetic Resonance Imaging, Male, Mice, Mice, Inbred C57BL, Neocortex drug effects, Neuroimaging, Status Epilepticus diagnostic imaging, Status Epilepticus physiopathology, Video Recording, Neocortex injuries, Status Epilepticus etiology
- Abstract
Objective: To characterize neocortical onset status epilepticus (SE) in the C57BL/6J mouse., Methods: We induced SE by administering homocysteine 16-18 hours after cobalt (Co) implantation. SE was monitored by video and electroencephalography (EEG). We evaluated brain structure with magnetic resonance imaging (MRI). Neurodegeneration was evaluated 72 hours after SE using Fluoro-Jade C staining., Results: Cobalt triggered seizures in a dose-dependent manner (median effective dose, ED
50 = 0.78 mg) and the latency to peak seizure frequency shortened with increased dose. Animals developed SE after homocysteine administration. SE began with early intermittent focal seizures, consisting of frontal onset rhythmic spike-wave discharges manifested as focal dystonia with clonus. These focal seizures then evolved into generalized continuous convulsive activity. Behavioral manifestations of SE included tonic stiffening, bilateral limb clonus, and bilateral tonic-clonic movements, which were accompanied by generalized rhythmic spike-wave discharges on EEG. After prolonged seizures, animals became comatose with intermittent bilateral myoclonic seizures or jerks. During this period, EEG showed seizures interspersed with generalized periodic discharges on a suppressed background. MRI obtained when animals were in a coma revealed edema, midline shift in frontal lobe around the Co implantation site, and ventricular effacement. Fluoro-Jade C staining revealed neurodegeneration in the cortex, amygdala, and thalamus., Significance: We have developed a mouse model of severe, refractory cortical-onset SE, consisting of convulsions merging into a coma, EEG patterns of cortical seizures, and injury, with evidence of widespread neocortical edema and damage. This model replicates many features of acute seizures and SE resulting from traumatic brain injury, subarachnoid, and lobar hemorrhage., (© 2020 International League Against Epilepsy.)- Published
- 2020
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22. Microbiota composition in bilateral healthy breast tissue and breast tumors.
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Klann E, Williamson JM, Tagliamonte MS, Ukhanova M, Asirvatham JR, Chim H, Yaghjyan L, and Mai V
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- Female, Humans, Pilot Projects, Bacteria isolation & purification, Breast Neoplasms microbiology, Microbiota
- Abstract
Purpose: Previous reports suggest that a complex microbiome exists within the female human breast that might contribute to breast cancer etiology. The purpose of this pilot study was to assess the variation in microbiota composition by breast side (left versus right) within individual women and compare the microbiota of normal and breast tumor tissue between women. We aimed to determine whether microbiota composition differs between these groups and whether certain bacterial taxa may be associated with breast tumors., Methods: Bilateral normal breast tissue samples (n = 36) were collected from ten women who received routine mammoplasty procedures. Archived breast tumor samples (n = 10) were obtained from a biorepository. DNA was extracted, amplified, and sequenced. Microbiota data were analyzed using QIIME and RStudio., Results: The most abundant phyla in both tumor and normal tissues were Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria. There were statistically significant differences in the relative abundance of various bacterial taxa between groups. Alpha diversity (Simpson's index) was significantly higher in normal compared to tumor samples (0.968 vs. 0.957, p = 0.022). Based on unweighted UniFrac measures, breast tumor samples clustered distinctly from normal samples (R
2 = 0.130; p = 0.01). Microbiota composition in normal samples clustered within women (R2 = 0.394; p = 0.01) and by breast side (left or right) within a woman (R2 = 0.189; p = 0.03)., Conclusion: Significant differences in diversity between tumor and normal tissue and in composition between women and between breasts of the same woman were identified. These results warrant further research to investigate the relationship between microbiota and breast cancer.- Published
- 2020
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23. Manipulating Neuronal Activity in the Developing Zebrafish Spinal Cord to Investigate Adaptive Myelination.
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Williamson JM, Lyons DA, and Almeida RG
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- Animals, Animals, Genetically Modified, Female, Genetic Testing, Male, Models, Animal, Neurons metabolism, Oligodendroglia metabolism, Single-Cell Analysis, Spinal Cord cytology, Workflow, Zebrafish growth & development, Myelin Sheath metabolism, Neurons cytology, Oligodendroglia cytology, Spinal Cord growth & development, Zebrafish genetics
- Abstract
In the central nervous system, oligodendrocyte-lineage cells and myelination can adapt to physiological brain activity. Since myelin can in turn regulate neuronal function, such "adaptive" myelination has been proposed as a form of nervous system plasticity, implicated in learning and cognition. The molecular and cellular mechanisms underlying adaptive myelination and its functional consequences remain to be fully defined, partly because it remains challenging to manipulate activity and monitor myelination over time in vivo at single-cell resolution, in a model that would also allow examination of the functional output of individual neurons and circuits. Here, we describe a workflow to manipulate neuronal activity and to assess oligodendrocyte-lineage cell dynamics and myelination in larval zebrafish, a vertebrate animal model that is ideal for live imaging and amenable to genetic discovery, and that has well-characterized neuronal circuits with myelinated axons.
- Published
- 2019
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24. Myelin Dynamics Throughout Life: An Ever-Changing Landscape?
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Williamson JM and Lyons DA
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Myelin sheaths speed up impulse propagation along the axons of neurons without the need for increasing axon diameter. Subsequently, myelin (which is made by oligodendrocytes in the central nervous system) allows for highly complex yet compact circuitry. Cognitive processes such as learning require central nervous system plasticity throughout life, and much research has focused on the role of neuronal, in particular synaptic, plasticity as a means of altering circuit function. An increasing body of evidence suggests that myelin may also play a role in circuit plasticity and that myelin may be an adaptable structure which could be altered to regulate experience and learning. However, the precise dynamics of myelination throughout life remain unclear - does the production of new myelin require the differentiation of new oligodendrocytes, and/or can existing myelin be remodelled dynamically over time? Here we review recent evidence for both de novo myelination and myelin remodelling from pioneering longitudinal studies of myelin dynamics in vivo , and discuss what remains to be done in order to fully understand how dynamic regulation of myelin affects lifelong circuit function.
- Published
- 2018
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25. Relative Contribution of Schistosomiasis and Malaria to Anemia in Western Kenya.
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Valice EM, Wiegand RE, Mwinzi PNM, Karanja DMS, Williamson JM, Ochola E, Samuels A, Verani JR, Leon JS, Secor WE, and Montgomery SP
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- Adolescent, Anemia epidemiology, Child, Child, Preschool, Humans, Infant, Kenya epidemiology, Malaria, Falciparum epidemiology, Models, Biological, Risk Factors, Schistosomiasis mansoni epidemiology, Anemia etiology, Coinfection complications, Malaria, Falciparum complications, Schistosomiasis mansoni complications
- Abstract
Because anemia is one of the markers of morbidity associated with schistosomiasis, it has been proposed as a potential measure to evaluate the impact of control programs. However, anemia is also a common consequence of malaria, and schistosomiasis and malaria are often co-endemic. To estimate the attributable fraction of anemia due to Schistosoma mansoni and Plasmodium falciparum infections, we applied a log-binomial model to four studies measuring these parameters of a combined 5,849 children in western Kenya. In our studies, malaria contributed 23.3%, schistosomiasis contributed 6.6%, and co-infection contributed 27.6% of the anemia. We conclude that in areas where S. mansoni and P. falciparum are co-endemic, the contribution of schistosomiasis to anemia is masked by anemia resulting from malaria, thus limiting anemia as a useful measure for schistosomiasis control programs in these settings.
- Published
- 2018
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26. An automated high-resolution in vivo screen in zebrafish to identify chemical regulators of myelination.
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Early JJ, Cole KL, Williamson JM, Swire M, Kamadurai H, Muskavitch M, and Lyons DA
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- Animals, Animals, Genetically Modified, Automation, Cell Count, Fluorescence, High-Throughput Screening Assays, Image Processing, Computer-Assisted, Larva metabolism, Naphthalenes pharmacology, Oligodendroglia cytology, Pyrones pharmacology, Reproducibility of Results, Spinal Cord metabolism, Time-Lapse Imaging, Genetic Testing, Myelin Sheath metabolism, Zebrafish genetics
- Abstract
Myelinating oligodendrocytes are essential for central nervous system (CNS) formation and function. Their disruption is implicated in numerous neurodevelopmental, neuropsychiatric and neurodegenerative disorders. However, recent studies have indicated that oligodendrocytes may be tractable for treatment of disease. In recent years, zebrafish have become well established for the study of myelinating oligodendrocyte biology and drug discovery in vivo. Here, by automating the delivery of zebrafish larvae to a spinning disk confocal microscope, we were able to automate high-resolution imaging of myelinating oligodendrocytes in vivo. From there, we developed an image analysis pipeline that facilitated a screen of compounds with epigenetic and post-translational targets for their effects on regulating myelinating oligodendrocyte number. This screen identified novel compounds that strongly promote myelinating oligodendrocyte formation in vivo. Our imaging platform and analysis pipeline is flexible and can be employed for high-resolution imaging-based screens of broad interest using zebrafish., Competing Interests: JE, MS, DL No competing interests declared, KC funded by a collaborative grant from Biogen for part of the period of this project, JW Jill M Williamson: funded by a collaborative grant from Biogen for part of the period of this project, HK was employed by Biogen at the time of the study, MM Marc Muskavitch: was employed by Biogen at the time of the study, (© 2018, Early et al.)
- Published
- 2018
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27. Myelination of Neuronal Cell Bodies when Myelin Supply Exceeds Axonal Demand.
- Author
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Almeida RG, Pan S, Cole KLH, Williamson JM, Early JJ, Czopka T, Klingseisen A, Chan JR, and Lyons DA
- Subjects
- Animals, Animals, Genetically Modified, Axons metabolism, Axons physiology, Female, Male, Mice, Myelin Sheath physiology, Nerve Fibers, Myelinated metabolism, Neurons physiology, Oligodendroglia metabolism, Organogenesis physiology, Zebrafish metabolism, Zebrafish physiology, Zebrafish Proteins metabolism, Cell Body metabolism, Myelin Sheath metabolism, Nerve Fibers, Myelinated physiology
- Abstract
The correct targeting of myelin is essential for nervous system formation and function. Oligodendrocytes in the CNS myelinate some axons, but not others, and do not myelinate structures including cell bodies and dendrites [1]. Recent studies indicate that extrinsic signals, such as neuronal activity [2, 3] and cell adhesion molecules [4], can bias myelination toward some axons and away from cell bodies and dendrites, indicating that, in vivo, neuronal and axonal cues regulate myelin targeting. In vitro, however, oligodendrocytes have an intrinsic propensity to myelinate [5-7] and can promiscuously wrap inert synthetic structures resembling neuronal processes [8, 9] or cell bodies [4]. A current therapeutic goal for the treatment of demyelinating diseases is to greatly promote oligodendrogenesis [10-13]; thus, it is important to test how accurately extrinsic signals regulate the oligodendrocyte's intrinsic program of myelination in vivo. Here, we test the hypothesis that neurons regulate myelination with sufficient stringency to always ensure correct targeting. Surprisingly, however, we find that myelin targeting in vivo is not very stringent and that mistargeting occurs readily when oligodendrocyte and myelin supply exceed axonal demand. We find that myelin is mistargeted to neuronal cell bodies in zebrafish mutants with fewer axons and independently in drug-treated zebrafish with increased oligodendrogenesis. Additionally, by increasing myelin production of oligodendrocytes in zebrafish and mice, we find that excess myelin is also inappropriately targeted to cell bodies. Our results suggest that balancing oligodendrocyte-intrinsic programs of myelin supply with axonal demand is essential for correct myelin targeting in vivo and highlight potential liabilities of strongly promoting oligodendrogenesis., (Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2018
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28. Prevalence of Hepatitis B Virus Infection in Kenya, 2007.
- Author
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Ly KN, Kim AA, Umuro M, Drobenuic J, Williamson JM, Montgomery JM, Fields BS, and Teshale EH
- Subjects
- Adolescent, Adult, Female, Health Surveys, Hepatitis B virus immunology, Hepatitis B, Chronic diagnosis, Hepatitis B, Chronic immunology, Hepatitis B, Chronic virology, Humans, Kenya epidemiology, Male, Middle Aged, Odds Ratio, Prevalence, Risk Factors, Hepatitis B Antibodies blood, Hepatitis B Core Antigens blood, Hepatitis B Surface Antigens blood, Hepatitis B virus isolation & purification, Hepatitis B, Chronic epidemiology
- Abstract
Current estimates put the prevalence of hepatitis B virus (HBV) infection in Kenya at 5-8%. We determined the HBV infection prevalence in the human immunodeficiency virus (HIV)-negative Kenyan adult and adolescent population based on samples collected from a national survey. We analyzed data from HIV-negative participants in the 2007 Kenya AIDS Indicator Survey to estimate the HBV infection prevalence. We defined past or present HBV infection as presence of total hepatitis B core antibody (HBcAb), and chronic HBV infection (CHBI) as presence of both total HBcAb and hepatitis B surface antigen (HBsAg). We calculated crude and adjusted odds of HBV infection by demographic characteristics and risk factors using logistic regression analyses. Of 1,091 participants aged 15-64 years, approximately 31.5% (95% confidence interval [CI] = 28.0-35.3%) had exposure to HBV, corresponding to approximately 6.1 million (CI = 5.4-6.8 million) with past or present HBV infection. The estimated prevalence of CHBI was 2.1% (95% CI = 1.4-3.1%), corresponding to approximately 398,000 (CI = 261,000-602,000) with CHBI. CHBI is a major public health problem in Kenya, affecting approximately 400,000 persons. Knowing the HBV infection prevalence at baseline is important for planning and public health policy decision making and for monitoring the impact of viral hepatitis prevention programs., (© The American Society of Tropical Medicine and Hygiene.)
- Published
- 2016
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29. Power and sample size calculations for interval-censored survival analysis.
- Author
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Kim HY, Williamson JM, and Lin HM
- Subjects
- Biostatistics, Breast Neoplasms therapy, Computer Simulation, Female, Humans, Longitudinal Studies, Models, Statistical, Proportional Hazards Models, Regression Analysis, Sample Size, Time Factors, Survival Analysis
- Abstract
We propose a method for calculating power and sample size for studies involving interval-censored failure time data that only involves standard software required for fitting the appropriate parametric survival model. We use the framework of a longitudinal study where patients are assessed periodically for a response and the only resultant information available to the investigators is the failure window: the time between the last negative and first positive test results. The survival model is fit to an expanded data set using easily computed weights. We illustrate with a Weibull survival model and a two-group comparison. The investigator can specify a group difference in terms of a hazards ratio. Our simulation results demonstrate the merits of these proposed power calculations. We also explore how the number of assessments (visits), and thus the corresponding lengths of the failure intervals, affect study power. The proposed method can be easily extended to more complex study designs and a variety of survival and censoring distributions., (Copyright © 2015 John Wiley & Sons, Ltd.)
- Published
- 2016
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30. Anaemia in HIV-infected pregnant women receiving triple antiretroviral combination therapy for prevention of mother-to-child transmission: a secondary analysis of the Kisumu breastfeeding study (KiBS).
- Author
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Odhiambo C, Zeh C, Angira F, Opollo V, Akinyi B, Masaba R, Williamson JM, Otieno J, Mills LA, Lecher SL, and Thomas TK
- Subjects
- Adult, Anemia epidemiology, CD4 Lymphocyte Count, Female, HIV Infections complications, Hemoglobins analysis, Humans, Kenya epidemiology, Pregnancy, Prevalence, Viral Load, Anemia etiology, Antiretroviral Therapy, Highly Active, HIV Infections drug therapy, Infectious Disease Transmission, Vertical prevention & control, Pregnancy Complications, Infectious drug therapy
- Abstract
Objective: The prevalence of anaemia during pregnancy is estimated to be 35-75% in sub-Saharan Africa and is associated with an increased risk of maternal mortality. We evaluated the frequency and factors associated with anaemia in HIV-infected women undergoing antiretroviral (ARV) therapy for prevention of mother-to-child transmission (PMTCT) enrolled in The Kisumu Breastfeeding Study 2003-2009., Methods: Maternal haematological parameters were monitored from 32 to 34 weeks of gestation to 2 years post-delivery among 522 enrolled women. Clinical and laboratory assessments for causes of anaemia were performed, and appropriate management was initiated. Anaemia was graded using the National Institutes of Health Division of AIDS 1994 Adult Toxicity Tables. Data were analysed using SAS software, v 9.2. The Wilcoxon two-sample rank test was used to compare groups. A logistic regression model was fitted to describe the trend in anaemia over time., Results: At enrolment, the prevalence of any grade anaemia (Hb < 9.4 g/dl) was 61.8%, but fell during ARV therapy, reaching a nadir (7.4%) by 6 months post-partum. A total of 41 women (8%) developed severe anaemia (Hb < 7 g/dl) during follow-up; 2 (4.9%) were hospitalised for blood transfusion, whereas 3 (7.3%) were transfused while hospitalised (for delivery). The greatest proportion of severe anaemia events occurred around delivery (48.8%; n = 20). Anaemia (Hb ≥ 7 and < 9.4 g/dl) at enrolment was associated with severe anaemia at delivery (OR 5.87; 95% CI: 4.48, 7.68, P < 0.01). Few cases of severe anaemia coincided with clinical malaria (24.4%; n = 10) and helminth (7.3%; n = 3) infections., Conclusion: Resolution of anaemia among most participants during study follow-up was likely related to receipt of ARV therapy. Efforts should be geared towards addressing common causes of anaemia in HIV-infected pregnant women, prioritising initiation of ARV therapy and management of peripartum blood loss., (© 2016 John Wiley & Sons Ltd.)
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- 2016
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31. Metachronous small bowel metastasis from a mixed Müllerian mesodermal tumour.
- Author
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Williamson JM, Stevens M, and Mahon D
- Subjects
- Aged, Female, Humans, Hysterectomy, Intestinal Obstruction etiology, Intestinal Obstruction pathology, Carcinosarcoma, Intestinal Neoplasms, Intestine, Small pathology, Mixed Tumor, Mullerian
- Abstract
A mixed Müllerian mesodermal tumour (MMMT) is a rare aggressive carcinosarcoma. Metastatic progression is uncommon, and occurs via haematological, lymphatic and intraperitoneal spread. Although the latter is seen most frequently, the small intestine seems to be relatively preserved from disease progression with only one reported case of synchronous involvement. We report a case of metachronous MMMT involvement of the small bowel presenting with subacute obstruction that was successfully resected at operation.
- Published
- 2016
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32. Shouldering responsibility for intraoperative bariatric amputees.
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Williamson JM and Mahon D
- Subjects
- Humans, Obesity, Morbid complications, Amputees rehabilitation, Obesity, Morbid rehabilitation, Orthotic Devices standards, Patient Positioning methods, Shoulder, Wheelchairs standards
- Published
- 2016
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33. Emergence of Community-Acquired, Multidrug-Resistant Invasive Nontyphoidal Salmonella Disease in Rural Western Kenya, 2009-2013.
- Author
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Oneko M, Kariuki S, Muturi-Kioi V, Otieno K, Otieno VO, Williamson JM, Folster J, Parsons MB, Slutsker L, Mahon BE, and Hamel MJ
- Subjects
- Anti-Bacterial Agents pharmacology, Bacteremia complications, Bacteremia epidemiology, Bacteremia microbiology, Ceftriaxone pharmacology, Child, Preschool, Female, HIV Infections complications, HIV Infections microbiology, Hospitalization statistics & numerical data, Humans, Incidence, Infant, Kenya epidemiology, Malaria, Male, Outpatients statistics & numerical data, Residence Characteristics statistics & numerical data, Rural Population statistics & numerical data, Salmonella Infections complications, Salmonella Infections mortality, Time Factors, Drug Resistance, Multiple, Bacterial, Salmonella Infections epidemiology, Salmonella Infections microbiology, Salmonella enterica drug effects
- Abstract
Background: Nontyphoidal Salmonella (NTS), mainly serotypes Typhimurium and Enteritidis, cause invasive infections with high mortality in children in sub-Saharan Africa. Multidrug resistance is common, and resistance to third-generation cephalosporins has emerged., Methods: We reviewed clinical features, outcomes, and antimicrobial resistance patterns in invasive NTS infections among children aged 6 weeks to 5 years participating in malaria vaccine studies in an area of high malaria and human immunodeficiency virus (HIV) transmission in Siaya, western Kenya. Blood culture was performed in hospitalized children and pediatric outpatients with prolonged fever., Results: From July 2009 to December 2013, 1696 children aged 6 weeks to 17 months were enrolled into vaccine trials and followed for up to 53 months. We obtained 1692 blood cultures from 847 children. Of 134 bacterial pathogens isolated, 102 (76.1%) were Salmonella serogroup B or D. Invasive NTS disease occurred in 94 (5.5%) children, with an incidence of 1870, 4134, and 6510 episodes per 100 000 person-years overall, in infants, and in HIV-infected children, respectively. Malaria infection within the past 2 weeks occurred in 18.8% (3/16) of invasive NTS episodes in HIV-infected and 66.2% (53/80) in HIV-uninfected children. Case fatality rate was 3.1%. Salmonella group B resistant to ceftriaxone emerged in 2009 and 2010 (6.2% [2/32 isolates]), rising to 56.5% (13/23 isolates) in 2012 and 2013., Conclusions: Incidence of invasive NTS disease was high in this area of high malaria and HIV transmission, especially in HIV-infected children. Rapidly emerging resistance against ceftriaxone requires urgent reevaluation of antibiotic recommendations and primary prevention of exposure to Salmonella., (© The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2015
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34. Increased Rates of Respiratory and Diarrheal Illnesses in HIV-Negative Persons Living With HIV-Infected Individuals in a Densely Populated Urban Slum in Kenya.
- Author
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Wong JM, Cosmas L, Nyachieo D, Williamson JM, Olack B, Okoth G, Njuguna H, Feikin DR, Burke H, Montgomery JM, and Breiman RF
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Child, Child, Preschool, Female, Humans, Incidence, Kenya, Male, Middle Aged, Poverty Areas, Prevalence, Risk Assessment, Urban Population, Young Adult, Diarrhea epidemiology, Environmental Exposure, Family Characteristics, HIV Infections, Respiratory Tract Infections epidemiology
- Abstract
Background: Prolonged pathogen shedding and increased duration of illness associated with infections in immunosuppressed individuals put close human immunodeficiency virus (HIV)-negative contacts of HIV-infected persons at increased risk of exposure to infectious pathogens., Methods: We calculated incidence and longitudinal prevalence (number of days per year) of influenzalike illness (ILI), diarrhea, and nonspecific febrile illness during 2008 from a population-based surveillance program in the urban slum of Kibera (Kenya) that included 1830 HIV-negative household contacts of HIV-infected individuals and 13 677 individuals living in exclusively HIV-negative households., Results: For individuals ≥5 years old, incidence was significantly increased for ILI (risk ratio [RR], 1.47; P < .05) and diarrhea (RR, 1.41; P < .05) in HIV-negative household contacts of HIV-infected individuals compared with exclusively HIV-negative households. The risk of illness among HIV-negative persons was directly proportional to the number of HIV-infected persons living in the home for ILI (RR, 1.39; P < .05) and diarrhea (RR, 1.36; P < .01). We found no increased rates of illness in children <5 years old who lived with HIV-infected individuals., Conclusions: Living with HIV-infected individuals is associated with modestly increased rates of respiratory and diarrheal infections in HIV-negative individuals >5 years old. Targeted interventions are needed, including ensuring that HIV-infected persons are receiving appropriate care and treatment., (Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.)
- Published
- 2015
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35. Delayed laparoscopic mesh infection presenting as an abdominal mass.
- Author
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Williamson JM, Newman P, and Armstrong CP
- Subjects
- Herniorrhaphy instrumentation, Herniorrhaphy methods, Humans, Laparoscopy, Male, Middle Aged, Postoperative Period, Prosthesis-Related Infections therapy, Tomography, X-Ray Computed, Hernia, Inguinal surgery, Herniorrhaphy adverse effects, Prosthesis-Related Infections diagnostic imaging, Surgical Mesh adverse effects
- Abstract
A 56-year-old man presented with a delayed mesh infection 8 years following an elective laparoscopic totally extraperitoneal (TEP) bilateral hernia repair. Sterile pus was drained percutaneously as a temporising measure prior to removal of the right-hand mesh; the left-sided mesh was adherent to the femoral vessels and minimally contaminated. Delayed mesh infection is a rare occurrence. This case is the fourth example and the longest following initial operation. Removal of the infected mesh is advocated.
- Published
- 2015
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36. A Simple Approach for Sample Size Calculation for Comparing Two Concordance Correlation Coefficients Estimated on the Same Subjects.
- Author
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Lin HM and Williamson JM
- Subjects
- Algorithms, Carotid Stenosis diagnosis, Computer Simulation, Data Interpretation, Statistical, Databases, Factual, Humans, Linear Models, Magnetic Resonance Angiography, Reproducibility of Results, Sample Size
- Abstract
Some studies are designed to assess the agreement between different raters and/or different instruments in the medical sciences and pharmaceutical research. In practice, the same sample will be used to compare the agreement of two or more assessment methods for simplicity and to take advantage of the positive correlation of the ratings. The concordance correlation coefficient (CCC) is often used as a measure of agreement when the rating is a continuous variable. We present an approach for calculating the sample size required for testing the equality of two CCCs, H0: CCC1 = CCC2 vs. HA: CCC1 ≠ CCC2, where two assessment methods are used on the same sample, with two raters resulting in correlated CCC estimates. Our approach is to simulate one large "exemplary" dataset based on the specification of the joint distribution of the pairwise ratings for the two methods. We then create two new random variables from the simulated data that have the same variance-covariance matrix as the two dependent CCC estimates using the Taylor series linearization method. The method requires minimal computing time and can be easily extended to comparing more than two CCCs, or Kappa statistics.
- Published
- 2015
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37. Delayed diaphragmatic rupture presenting with acute gastric volvulus.
- Author
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Williamson JM, Macleod R, and Hollowood A
- Subjects
- Acute Disease, Aged, 80 and over, Diagnosis, Differential, Fatal Outcome, Hernia, Diaphragmatic diagnostic imaging, Humans, Male, Radiography, Thoracic methods, Rupture, Spontaneous diagnosis, Stomach Volvulus diagnostic imaging, Tomography, X-Ray Computed methods, Hernia, Diaphragmatic diagnosis, Out-of-Hospital Cardiac Arrest, Stomach Volvulus diagnosis
- Abstract
Gastric volvulus is a rare complication of diaphragmatic rupture. We report the case of an 82-year-old man who presented following an out-of-hospital cardiac arrest. Chest radiography and thoracic computed tomography revealed an acute gastric volvulus and a chronic diaphragmatic hernia containing transverse colon and abdominal viscera. He had complained of retching and associated epigastric pain prior to collapse, and had sustained a motorcycle accident approximately 60 years earlier. Insertion of a nasogastric tube was unsuccessful (completing Borchardt's diagnostic triad) and his condition prevented both operative and endoscopic reduction of his volvulus. He died soon afterwards.
- Published
- 2014
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38. Sustained high incidence of injuries from burns in a densely populated urban slum in Kenya: an emerging public health priority.
- Author
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Wong JM, Nyachieo DO, Benzekri NA, Cosmas L, Ondari D, Yekta S, Montgomery JM, Williamson JM, and Breiman RF
- Subjects
- Adolescent, Adult, Age Distribution, Child, Child, Preschool, Female, Health Priorities, Humans, Incidence, Infant, Kenya epidemiology, Male, Middle Aged, Prospective Studies, Public Health, Sex Distribution, Urban Population statistics & numerical data, Young Adult, Accidents, Home statistics & numerical data, Burns epidemiology, Poverty Areas
- Abstract
Introduction: Ninety-five percent of burn deaths occur in low- and middle-income countries (LMICs); however, longitudinal household-level studies have not been done in urban slum settings, where overcrowding and unsafe cook stoves may increase likelihood of injury., Methods: Using a prospective, population-based disease surveillance system in the urban slum of Kibera in Kenya, we examined the incidence of household-level burns of all severities from 2006-2011., Results: Of approximately 28,500 enrolled individuals (6000 households), we identified 3072 burns. The overall incidence was 27.9/1000 person-years-of-observation. Children <5 years old sustained burns at 3.8-fold greater rate compared to (p<0.001) those ≥5 years old. Females ≥5 years old sustained burns at a rate that was 1.35-fold (p<0.001) greater than males within the same age distribution. Hospitalizations were uncommon (0.65% of all burns)., Conclusions: The incidence of burns, 10-fold greater than in most published reports from Africa and Asia, suggests that such injuries may contribute more significantly than previously thought to morbidity in LMICs, and may be increased by urbanization. As migration from rural areas into urban slums rapidly increases in many African countries, characterizing and addressing the rising burden of burns is likely to become a public health priority., (Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.)
- Published
- 2014
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39. Bile duct injury following laparoscopic cholecystectomy.
- Author
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Williamson JM
- Subjects
- Humans, Incidence, Risk Factors, Time Factors, Bile Ducts injuries, Bile Ducts surgery, Cholecystectomy, Laparoscopic adverse effects
- Published
- 2014
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40. Author's response.
- Author
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Williamson JM and Strickland A
- Subjects
- Female, Humans, Bile Duct Neoplasms surgery, Cystadenoma surgery, Liver Neoplasms surgery
- Published
- 2014
- Full Text
- View/download PDF
41. Endoscopic ultrasonography allowing expectant management of pancreatic haemangioma.
- Author
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Williamson JM, Finch-Jones M, and Pope I
- Subjects
- Aged, Female, Humans, Watchful Waiting, Endosonography methods, Hemangioma diagnostic imaging, Pancreatic Neoplasms diagnostic imaging, Rare Diseases diagnostic imaging
- Abstract
Pancreatic haemangiomas are rare benign tumours that can affect both adults and children. They have an unknown incidence and only 15 adult cases have been reported, all from histological examination. Patients present with vague symptoms relating to tumour mass or they are detected incidentally. Cross-sectional imaging is the mainstay of investigation and may reveal arterially enhancing cystic lesions but in the case presented here, it was non-diagnostic. The use of endoscopic ultrasonography confirmed the nature of the benign lesion, allowing a conservative approach as opposed to operative resection.
- Published
- 2014
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42. Surgical resection of hepatic and cardiac neuroendocrine metastases from a caecal primary tumour.
- Author
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Williamson JM, Anderson J, and Spalding DR
- Subjects
- Aged, Carcinoid Tumor diagnostic imaging, Carcinoid Tumor secondary, Heart Atria, Heart Neoplasms diagnostic imaging, Heart Neoplasms secondary, Heterocyclic Compounds, 1-Ring, Humans, Incidental Findings, Liver Neoplasms diagnostic imaging, Liver Neoplasms secondary, Magnetic Resonance Imaging, Male, Peptides, Cyclic, Pericardium, Postoperative Care, Radiopharmaceuticals, Somatostatin analogs & derivatives, Tomography, Emission-Computed, Single-Photon, Whole Body Imaging, Carcinoid Tumor surgery, Cecal Neoplasms surgery, Heart Neoplasms surgery, Liver Neoplasms surgery
- Abstract
A 66-year-old patient had an incidentally detected caecal neuroendocrine tumour that had metastasised to the liver and left atrium. He was asymptomatic with regard to this tumour and did not have carcinoid syndrome. Resection of the primary tumour and the metastatic deposits (with the ablation of one lesion) is thought to be curative.
- Published
- 2014
- Full Text
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43. A potassium leak channel silences hyperactive neurons and ameliorates status epilepticus.
- Author
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Dey D, Eckle VS, Vitko I, Sullivan KA, Lasiecka ZM, Winckler B, Stornetta RL, Williamson JM, Kapur J, and Perez-Reyes E
- Subjects
- Animals, Cell Death genetics, Cell Polarity genetics, Genetic Vectors administration & dosage, Genetic Vectors genetics, HEK293 Cells, Humans, Male, Neural Inhibition genetics, Neurons physiology, Potassium Channels, Tandem Pore Domain administration & dosage, Rats, Rats, Sprague-Dawley, Status Epilepticus pathology, Gene Transfer Techniques, Neurons pathology, Potassium Channels, Tandem Pore Domain genetics, Status Epilepticus genetics, Status Epilepticus prevention & control
- Abstract
Objective: To develop a constitutively active K(+) leak channel using TREK-1 (TWIK-related potassium channel 1; TREK-M) that is resistant to compensatory down-regulation by second messenger cascades, and to validate the ability of TREK-M to silence hyperactive neurons using cultured hippocampal neurons. To test if adenoassociated viral (AAV) delivery of TREK-M could reduce the duration of status epilepticus and reduce neuronal death induced by lithium-pilocarpine administration., Methods: Molecular cloning techniques were used to engineer novel vectors to deliver TREK-M via plasmids, lentivirus, and AAV using a cytomegalovirus (CMV)-enhanced GABRA4 promoter. Electrophysiology was used to characterize the activity and regulation of TREK-M in human embryonic kidney (HEK-293) cells, and the ability to reduce spontaneous activity in cultured hippocampal neurons. Adult male rats were injected bilaterally with self-complementary AAV particles composed of serotype 5 capsid into the hippocampus and entorhinal cortex. Lithium-pilocarpine was used to induce status epilepticus. Seizures were monitored using continuous video-electroencephalography (EEG) monitoring. Neuronal death was measured using Fluoro-Jade C staining of paraformaldehyde-fixed brain slices., Results: TREK-M inhibited neuronal firing by hyperpolarizing the resting membrane potential and decreasing input resistance. AAV delivery of TREK-M decreased the duration of status epilepticus by 50%. Concomitantly it reduced neuronal death in areas targeted by the AAV injection., Significance: These findings demonstrate that TREK-M can silence hyperexcitable neurons in the brain of epileptic rats and treat acute seizures. This study paves the way for an alternative gene therapy treatment of status epilepticus, and provides the rationale for studies of AAV-TREK-M's effect on spontaneous seizures in chronic models of temporal lobe epilepsy., (Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.)
- Published
- 2014
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44. A longitudinal analysis of the effect of mass drug administration on acute inflammatory episodes and disease progression in lymphedema patients in Leogane, Haiti.
- Author
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Eddy BA, Blackstock AJ, Williamson JM, Addiss DG, Streit TG, Beau de Rochars VM, and Fox LM
- Subjects
- Adolescent, Adult, Aged, Albendazole administration & dosage, Anthelmintics administration & dosage, Anthelmintics therapeutic use, Child, Diethylcarbamazine administration & dosage, Elephantiasis, Filarial epidemiology, Elephantiasis, Filarial pathology, Female, Haiti epidemiology, Humans, Ivermectin administration & dosage, Male, Middle Aged, Young Adult, Albendazole therapeutic use, Diethylcarbamazine therapeutic use, Elephantiasis, Filarial drug therapy, Inflammation pathology, Ivermectin therapeutic use
- Abstract
We conducted a longitudinal analysis of 117 lymphedema patients in a filariasis-endemic area of Haiti during 1995-2008. No difference in lymphedema progression between those who received or did not receive mass drug administration (MDA) was found on measures of foot (P = 0.24), ankle (P = 0.87), or leg (P = 0.46) circumference; leg volume displacement (P = 0.09), lymphedema stage (P = 0.93), or frequency of adenolymphangitis (ADL) episodes (P = 0.57). Rates of ADL per year were greater after initiation of MDA among both groups (P < 0.01). Nevertheless, patients who received MDA reported improvement in four areas of lymphedema-related quality of life (P ≤ 0.01). Decreases in foot and ankle circumference and ADL episodes were observed during the 1995-1998 lymphedema management study (P ≤ 0.01). This study represents the first longitudinal, quantitative, leg-specific analysis examining the clinical effect of diethylcarbamazine on lymphedema progression and ADL episodes.
- Published
- 2014
- Full Text
- View/download PDF
45. Small bowel tumors: pathology and management.
- Author
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Williamson JM and Williamson RC
- Subjects
- Diagnostic Imaging, Endoscopy, Gastrointestinal methods, Humans, Incidence, Intestinal Neoplasms etiology, Intestine, Small surgery, Risk Factors, Intestinal Neoplasms pathology, Intestinal Neoplasms therapy, Intestine, Small pathology
- Abstract
Despite comprising at least 75% of the length of the gastrointestinal tract, the small bowel only accounts for 3 to 6% of all its neoplasms. Forty different tumor subtypes arise from the small bowel; the commonest is adenoma, and malignant lesions include gastrointestinal stromal tumor neuroendocrine tumor lymphoma, and adenocarcinoma. Small bowel tumors typically cause either non-specific symptoms or none at all, which explains both the frequent delay in diagnosis and the wide range of potential investigations. The relative inaccessibility of the small bowel to endoscopic assessment is being challenged by the increased use of both capsule and double balloon endoscopy. Advances in endoscopic assessment are mirrored by improved sensitivity of radiological and nuclear imaging. Operative resection provides the mainstay of treatment for malignant disease (and symptomatic benign lesions), with oncological agents and somatostatin analogues providing useful adjuncts for inhibiting tumor growth and relieving symptoms. Survival reflects underlying tumor subtype, but is generally poor for malignant disease.
- Published
- 2014
46. Spectroscopic study of N2(b1Πu, ν = 8) by atmospheric-pressure resonant-enhanced multiphoton ionization and fluorescence detection.
- Author
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Adams SF and Williamson JM
- Abstract
A spectroscopic analysis of the strongly perturbed N2(b(1)Πu, ν = 8) state has been conducted, accounting for b(1)Πu(ν = 8) ← X (1)Σg(+)(ν = 0) transitions, for the first time, up to J' = 20. A novel laser spectroscopy technique, using a combination of resonant-enhanced multiphoton ionization and fluorescence detection at atmospheric pressure, avoids the severe effects of perturbation reported in past extreme vacuum ultraviolet absorption experiments that produced weak and unusable spectra for the ν = 8 level. The R, Q, and P branches of the three-photon absorption transition b(1)Πu(ν = 8) ← X(1)Σg(+)(ν = 0) were fit, allowing rotational term energy assignment up to J' = 20 and molecular constants to be determined. Evidence of the previously suspected perturbation in b(1)Πu(ν = 8) is clear in this data, with significant Λ-type doubling at higher J' along with an anomalous negative value determined for the centrifugal distortion coefficient.
- Published
- 2013
- Full Text
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47. Hepatobiliary cystadenomas.
- Author
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Williamson JM, Rees JR, Pope I, and Strickland A
- Subjects
- Adult, Aged, Bile Duct Neoplasms diagnosis, Bile Ducts, Intrahepatic, Cystadenoma diagnosis, Female, Humans, Incidental Findings, Liver Neoplasms diagnosis, Magnetic Resonance Imaging, Tomography, X-Ray Computed, Bile Duct Neoplasms surgery, Cystadenoma surgery, Liver Neoplasms surgery
- Abstract
Introduction: Hepatobiliary cystadenomas are rare cystic tumours that can arise from any portion of the biliary tract but most commonly develop intrahepatically. They typically cause non-specific symptoms and are often detected incidentally. Cystadenomas can be mistaken for simple hepatic cysts on radiological imaging, which leads to inadequate treatment. Hepatobiliary cystadenomas have a malignant predisposition and a high recurrence rate. Complete excision including hepatic resection is therefore generally recommended., Methods: Three cases of hepatobiliary cystadenoma were identified at one unit over a six-month period. Their clinical details and management are reported., Results: Three female patients are described aged 25, 37 and 73 years. One patient presented because of recurrent infection, one presented because of pressure related symptoms and one lesion was identified incidentally. All patients were investigated by ultrasonography and computed tomography (CT), two additionally had magnetic resonance imaging (MRI) and one had a liver biopsy. The tumours were 4-16cm in size and all lesions were excised by non-anatomical, parenchyma sparing resections. Histology revealed mixed epithelium with underlying ovarian-like stroma., Conclusions: The management of hepatic cystadenomas as well as operative and pathological findings are discussed. Preoperative ultrasonography, CT and MRI is recommended, and early referral for specialist hepatobiliary review is advised. Operative resection is also recommended and complete excision was achieved in these cases. This strategy is supported by the current literature and recurrence has been shown to be unlikely.
- Published
- 2013
- Full Text
- View/download PDF
48. Management of liver trauma.
- Author
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Williamson JM, Rees JR, Streets CG, Strickland AD, and Finch-Jones MD
- Subjects
- Disease Management, Humans, Liver, Wounds, Nonpenetrating
- Published
- 2013
- Full Text
- View/download PDF
49. Traumatic injuries to the biliary tree.
- Author
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Williamson JM
- Subjects
- Biliary Tract Surgical Procedures, Diagnostic Imaging, Disease Management, Humans, Incidence, Biliary Tract injuries, Wounds and Injuries complications, Wounds and Injuries diagnosis, Wounds and Injuries epidemiology, Wounds and Injuries therapy
- Published
- 2013
- Full Text
- View/download PDF
50. Estimating the effects of the Balanced Budget act of 1997 on the home health care use of the dually eligible: a natural experiments approach.
- Author
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Williamson JM
- Subjects
- Aged, Aged, 80 and over, Female, Health Care Surveys, Health Services Research, Hospitalization statistics & numerical data, Humans, Insurance, Health economics, Linear Models, Male, Medicaid statistics & numerical data, Medicare statistics & numerical data, Prospective Payment System, Socioeconomic Factors, United States epidemiology, Budgets legislation & jurisprudence, Eligibility Determination methods, Home Care Services economics, Home Care Services statistics & numerical data, Insurance, Health statistics & numerical data
- Abstract
This research examines the use of home health agency services used by older adults after the implementation of changes to Medicare's payment scheme mandated by the Balanced Budget Act (BBA) of 1997. The objective of this study is to identify differential effects the BBA may have had on home health service use between dually eligible and Medicare-only beneficiaries. The results of this study suggest that although dually eligible and Medicare-only beneficiaries experienced a substantial decline in home health service use, the dually eligible had a relatively larger decline. Following the BBA, the dually eligible had more office-based physician visits but fewer inpatient hospital days, relative to the Medicare-only population. Finally, the author estimates cost savings to Medicare due to the BBA to be $1 billion in the 2 years following the legislation, whereas Medicaid programs shouldered a larger percentage of the home health service bill.
- Published
- 2013
- Full Text
- View/download PDF
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