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3.
Phys Chem Chem Phys ; 25(24): 16222-16226, 2023 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-37288877

RESUMEN

The zinc iodine (ZI) redox flow battery (RFB) has emerged as a promising candidate for grid-scale electrical energy storage owing to its high energy density, low cost and environmental friendliness. In this work, ZI RFBs were made with electrodes comprising carbon nanotubes (CNT) with redox-active iron particles, yielding higher discharge voltages, power densities, and 90% lower charge transfer resistances compared to cells with inert carbon electrodes. Analysis of the polarization curves reveals that cells with iron-containing electrodes have lower mass transfer resistances and 100% increase in power density (44 mW cm-2 to 90 mW cm-2) at 110 mA cm-2 relative to cells with inert carbon electrodes.

4.
ERJ Open Res ; 7(3)2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34322542

RESUMEN

Type 1 myotonic dystrophy (DM1) causes sleep disordered breathing and respiratory failure due to a combination of obstructive sleep apnoea, reduced central drive and respiratory muscle weakness. Noninvasive ventilation (NIV) is commonly used for treating respiratory failure in neuromuscular disease; however, there have been few studies assessing the role of NIV in DM1. The aim of this retrospective service evaluation was to investigate the impact of NIV adherence on hypercapnia and symptoms of hypoventilation in patients with DM1. Data on capillary carbon dioxide tension (P CO2 ), lung function, adherence to NIV and symptoms of hypoventilation were obtained from the records of 40 patients with DM1. Mean capillary P CO2 significantly reduced from 6.81±1.17 kPa during supervised inpatient set-up to 5.93±0.82 kPa after NIV set-up (p<0.001). NIV adherence reduced from 7.8 (range: 1.0-11.0) h per 24 h during supervised inpatient set-up to 2.9 (0-10.4) h per 24 h in the community. Overall 72% of patients used NIV <5 h per 24 h during follow-up, including 11% who discontinued NIV completely. There was no correlation between adherence to NIV and changes in capillary P CO2 . Patients who reported symptomatic benefit (50%) had higher adherence than those who did not feel benefit (p<0.05). In conclusion, in patients with myotonic dystrophy with Type II respiratory failure maintaining adherence is challenging.

5.
Lancet Respir Med ; 9(9): 1050-1064, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33545086

RESUMEN

Although our understanding of the pathogenesis of empyema has grown tremendously over the past few decades, questions still remain on how to optimally manage this condition. It has been almost a decade since the publication of the MIST2 trial, but there is still an extensive debate on the appropriate use of intrapleural fibrinolytic and deoxyribonuclease therapy in patients with empyema. Given the scarcity of overall guidance on this subject, we convened an international group of 22 experts from 20 institutions across five countries with experience and expertise in managing adult patients with empyema. We did a literature and internet search for reports addressing 11 clinically relevant questions pertaining to the use of intrapleural fibrinolytic and deoxyribonuclease therapy in adult patients with bacterial empyema. This Position Paper, consisting of seven graded and four ungraded recommendations, was formulated by a systematic and rigorous process involving the evaluation of published evidence, augmented with provider experience when necessary. Panel members participated in the development of the final recommendations using the modified Delphi technique. Our Position Paper aims to address the existing gap in knowledge and to provide consensus-based recommendations to offer guidance in clinical decision making when considering the use of intrapleural therapy in adult patients with bacterial empyema.


Asunto(s)
Consenso , Desoxirribonucleasas/uso terapéutico , Empiema Pleural/tratamiento farmacológico , Fibrinolíticos/uso terapéutico , Adulto , Humanos
6.
Front Genet ; 11: 24, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32158465

RESUMEN

Mitochondrial complex I deficiency is associated with a diverse range of clinical phenotypes and can arise due to either mitochondrial DNA (mtDNA) or nuclear gene defects. We investigated two adult patients who exhibited non-syndromic neurological features and evidence of isolated mitochondrial complex I deficiency in skeletal muscle biopsies. The first presented with indolent myopathy, progressive since age 17, while the second developed deafness around age 20 and other relapsing-remitting neurological symptoms since. A novel, likely de novo, frameshift variant in MT-ND6 (m.14512_14513del) and a novel maternally-inherited transversion mutation in MT-ND1 were identified, respectively. Skewed tissue segregation of mutant heteroplasmy level was observed; the mutant heteroplasmy levels of both variants were greater than 70% in muscle homogenate, however, in blood the MT-ND6 variant was undetectable while the mutant heteroplasmy level of the MT-ND1 variant was low (12%). Assessment of complex I assembly by Blue-Native PAGE demonstrated a decrease in fully assembled complex I in the muscle of both cases. SDS-PAGE and immunoblotting showed decreased levels of mtDNA-encoded ND1 and several nuclear encoded complex I subunits in both cases, consistent with functional pathogenic consequences of the identified variants. Pathogenicity of the m.14512_14513del was further corroborated by single-fiber segregation studies.

7.
Brain ; 143(2): 452-466, 2020 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-32040565

RESUMEN

Brody disease is an autosomal recessive myopathy characterized by exercise-induced muscle stiffness due to mutations in the ATP2A1 gene. Almost 50 years after the initial case presentation, only 18 patients have been reported and many questions regarding the clinical phenotype and results of ancillary investigations remain unanswered, likely leading to incomplete recognition and consequently under-diagnosis. Additionally, little is known about the natural history of the disorder, genotype-phenotype correlations, and the effects of symptomatic treatment. We studied the largest cohort of Brody disease patients to date (n = 40), consisting of 22 new patients (19 novel mutations) and all 18 previously published patients. This observational study shows that the main feature of Brody disease is an exercise-induced muscle stiffness of the limbs, and often of the eyelids. Onset begins in childhood and there was no or only mild progression of symptoms over time. Four patients had episodes resembling malignant hyperthermia. The key finding at physical examination was delayed relaxation after repetitive contractions. Additionally, no atrophy was seen, muscle strength was generally preserved, and some patients had a remarkable athletic build. Symptomatic treatment was mostly ineffective or produced unacceptable side effects. EMG showed silent contractures in approximately half of the patients and no myotonia. Creatine kinase was normal or mildly elevated, and muscle biopsy showed mild myopathic changes with selective type II atrophy. Sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA) activity was reduced and western blot analysis showed decreased or absent SERCA1 protein. Based on this cohort, we conclude that Brody disease should be considered in cases of exercise-induced muscle stiffness. When physical examination shows delayed relaxation, and there are no myotonic discharges at electromyography, we recommend direct sequencing of the ATP2A1 gene or next generation sequencing with a myopathy panel. Aside from clinical features, SERCA activity measurement and SERCA1 western blot can assist in proving the pathogenicity of novel ATP2A1 mutations. Finally, patients with Brody disease may be at risk for malignant hyperthermia-like episodes, and therefore appropriate perioperative measures are recommended. This study will help improve understanding and recognition of Brody disease as a distinct myopathy in the broader field of calcium-related myopathies.


Asunto(s)
Enfermedades Musculares/genética , Mutación/genética , Miotonía Congénita/genética , Retículo Sarcoplasmático/metabolismo , Adolescente , Adulto , ATPasas Transportadoras de Calcio/genética , Niño , Femenino , Humanos , Masculino , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiopatología , Fenotipo , Adulto Joven
8.
JAMA ; 323(1): 60-69, 2020 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-31804680

RESUMEN

Importance: Malignant pleural effusion (MPE) is challenging to manage. Talc pleurodesis is a common and effective treatment. There are no reliable data, however, regarding the optimal method for talc delivery, leading to differences in practice and recommendations. Objective: To test the hypothesis that administration of talc poudrage during thoracoscopy with local anesthesia is more effective than talc slurry delivered via chest tube in successfully inducing pleurodesis. Design, Setting, and Participants: Open-label, randomized clinical trial conducted at 17 UK hospitals. A total of 330 participants were enrolled from August 2012 to April 2018 and followed up until October 2018. Patients were eligible if they were older than 18 years, had a confirmed diagnosis of MPE, and could undergo thoracoscopy with local anesthesia. Patients were excluded if they required a thoracoscopy for diagnostic purposes or had evidence of nonexpandable lung. Interventions: Patients randomized to the talc poudrage group (n = 166) received 4 g of talc poudrage during thoracoscopy while under moderate sedation, while patients randomized to the control group (n = 164) underwent bedside chest tube insertion with local anesthesia followed by administration of 4 g of sterile talc slurry. Main Outcomes and Measures: The primary outcome was pleurodesis failure up to 90 days after randomization. Secondary outcomes included pleurodesis failure at 30 and 180 days; time to pleurodesis failure; number of nights spent in the hospital over 90 days; patient-reported thoracic pain and dyspnea at 7, 30, 90, and 180 days; health-related quality of life at 30, 90, and 180 days; all-cause mortality; and percentage of opacification on chest radiograph at drain removal and at 30, 90, and 180 days. Results: Among 330 patients who were randomized (mean age, 68 years; 181 [55%] women), 320 (97%) were included in the primary outcome analysis. At 90 days, the pleurodesis failure rate was 36 of 161 patients (22%) in the talc poudrage group and 38 of 159 (24%) in the talc slurry group (adjusted odds ratio, 0.91 [95% CI, 0.54-1.55]; P = .74; difference, -1.8% [95% CI, -10.7% to 7.2%]). No statistically significant differences were noted in any of the 24 prespecified secondary outcomes. Conclusions and Relevance: Among patients with malignant pleural effusion, thoracoscopic talc poudrage, compared with talc slurry delivered via chest tube, resulted in no significant difference in the rate of pleurodesis failure at 90 days. However, the study may have been underpowered to detect small but potentially important differences. Trial Registration: ISRCTN Identifier: ISRCTN47845793.


Asunto(s)
Derrame Pleural Maligno/terapia , Pleurodesia/métodos , Talco/administración & dosificación , Anciano , Tubos Torácicos , Drenaje , Femenino , Humanos , Masculino , Persona de Mediana Edad , Toracoscopía , Insuficiencia del Tratamiento
9.
Rheumatology (Oxford) ; 58(3): 468-475, 2019 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-30496561

RESUMEN

OBJECTIVES: To assess the performance of the EULAR/ACR idiopathic inflammatory myopathies (IIMs) classification criteria in a cohort of incident IIM cases and examine how criteria-assigned IIM subtype correlates with expert opinion. METHODS: Adults with newly diagnosed IIM attending Salford Royal NHS Foundation Trust were identified over a 10 year period. A retrospective review of all putative cases was performed and those fulfilling a consensus expert opinion diagnosis of IIM were included. Clinical, serological and histological data were collected and each case was assigned a single IIM subtype. The EULAR/ACR classification criteria were then applied and sensitivity, specificity and positive and negative predictive values were calculated, presented with 95% CIs. RESULTS: A total of 1637 cases were screened, with 255 consensus expert opinion IIM cases ultimately identified. Applying the EULAR/ACR classification criteria, the sensitivity to diagnose an IIM was 99.6% (95% CI 97.2, 100) and 80.9% (95% CI 76.0, 85.8) for the criteria cut-points of probable and definite diagnoses, respectively. In 94/255 cases the IIM subtype differed between consensus expert opinion and classification criteria, most strikingly in the group subtyped as PM by the EULAR/ACR criteria, where there was discrepancy in the majority (i.e. in 87/161). CONCLUSION: The EULAR/ACR criteria performed with high sensitivity in identifying IIM in this external cohort of incident IIM. However, substantial disagreements arose between consensus expert opinion and the criteria regarding IIM subtype assignments, resulting in a large proportion of criteria-assigned cases of PM having heterogeneous features. These results may have important implications for future use of these criteria in subsequent research.


Asunto(s)
Miositis/clasificación , Miositis/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Incidencia , Masculino , Tamizaje Masivo , Persona de Mediana Edad , Miositis/epidemiología , Sensibilidad y Especificidad , Adulto Joven
10.
Rheumatology (Oxford) ; 57(6): 1041-1046, 2018 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-29538753

RESUMEN

Objectives: Limitations in the methods available for identifying cardiac involvement and accurately quantifying disease activity in the idiopathic inflammatory myopathies (IIMs) may contribute to poor outcomes. We investigated the utility of different serum muscle damage markers [total creatine kinase (CK), cardiac troponin T (cTnT) and cardiac troponin I (cTnI)] to address these issues. Methods: We assessed disease activity and cardiac involvement using the International Myositis Assessment and Clinical Studies Group core set measures in 123 participants with confirmed adult-onset IIM from the UK and Denmark. Total CK, cTnT and cTnI were measured. Associations were assessed using logistic regression and Spearman's ranked correlation. Results: Cardiac involvement (n = 18) was associated with higher cTnI levels, independent of overall disease activity [adjusted odds ratio 1.03 (95% CI 1.01, 1.05); P = 0.002]. An abnormal cTnI had the highest specificity and positive predictive value for cardiac involvement (95% and 62%, respectively). In those with a normal CK but elevated cTnT or cTnI, an association with increased disease activity scores was observed. Serum cTnT correlated with the physician (ρ = 0.39) and patient-assessed (ρ = 0.28) global visual analogue scales and HAQ (ρ = 0.41) more strongly than CK or cTnI levels. cTnT was the only marker to correlate with manual muscle testing scores (ρ = -0.24). Conclusion: Serum cTnI testing may have a role in screening for cardiac involvement in IIMs. Abnormal levels of serum cTnT and cTnI are associated with increased disease activity, including in those with a normal CK.


Asunto(s)
Cardiomiopatías/sangre , Miositis/sangre , Troponina I/sangre , Troponina T/sangre , Biomarcadores/sangre , Cardiomiopatías/epidemiología , Cardiomiopatías/etiología , Dinamarca/epidemiología , Ecocardiografía , Electrocardiografía , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Miositis/complicaciones , Miositis/diagnóstico , Valor Predictivo de las Pruebas , Prevalencia , Curva ROC , Índice de Severidad de la Enfermedad , Reino Unido/epidemiología
11.
BMJ Case Rep ; 20182018 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-29437773

RESUMEN

A 43-year-old woman with a history of recently diagnosed metastatic melanoma was commenced on systemic therapy with nivolumab, an anti-programmed cell death-1 monoclonal antibody and one of an increasing group of the so-called 'immune checkpoint inhibitors'. She experienced a dramatic complete response within 6 months of initiation. However, in addition to developing incident autoimmune hypothyroidism, she also developed progressive fatigue, proximal weakness, myalgia and dysphagia. Initial investigations with blood tests, electrophysiology and a muscle biopsy were non-specific or normal. Subsequent examination revealed 'woody' thickening of the subcutaneous tissues of the forearms, thighs and calves consistent with fasciitis. MRI and a full-thickness skin-muscle biopsy were ultimately diagnostic of a likely iatrogenic autoimmune myofasciitis. The clinical manifestations only responded partly to prednisolone 30 mg orally and treatment was escalated to include intravenous immunoglobulin. At 3 months, this has only resulted in a modest incremental improvement.


Asunto(s)
Anticuerpos Monoclonales/efectos adversos , Antineoplásicos/efectos adversos , Enfermedades Autoinmunes/inducido químicamente , Antígeno B7-H1/efectos adversos , Fascitis/inducido químicamente , Melanoma/tratamiento farmacológico , Anticuerpos Monoclonales/administración & dosificación , Antineoplásicos/administración & dosificación , Enfermedades Autoinmunes/diagnóstico por imagen , Enfermedades Autoinmunes/tratamiento farmacológico , Biopsia , Fascitis/diagnóstico por imagen , Fascitis/tratamiento farmacológico , Femenino , Humanos , Inmunoglobulinas Intravenosas/uso terapéutico , Inmunoterapia/efectos adversos , Imagen por Resonancia Magnética , Melanoma/patología , Persona de Mediana Edad , Nivolumab
12.
Rheumatol Adv Pract ; 2(2): rky035, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-31431976

RESUMEN

OBJECTIVES: The aim was to identify and characterize all incident adult cases of idiopathic inflammatory myopathies (IIM) between 1 January 2007 and 31 December 2016 in the City of Salford, UK. METHODS: Adults first diagnosed with IIM within the study period were identified by: a Salford Royal NHS Foundation Trust (SRFT) inpatient episode IIM-specific ICD-10 coding search; all new patient appointments to SRFT neuromuscular outpatient clinics; and all Salford residents enrolled within the UKMYONET study. All patients with definite IIM by the 2017 EULAR/ACR classification criteria were included, as were probable cases if consensus expert opinion agreed. Cases were excluded if <18 years of age at disease onset, if they did not meet probable criteria or when probable but expert opinion concluded a non-IIM diagnosis. RESULTS: The multimodal case ascertainment identified 1156 cases which, after review and application of exclusion criteria, resulted in 32 incident cases during the study period. Twenty-three of 32 were female, with a mean age of 58.1 years. The mean incidence of adult IIM was 17.6/1 000 000 person years, and higher for females than for males (25.2 vs 10.0/1 000 000 person years, respectively). A significant incidence increase over time was apparent (13.6 vs 21.4/1 000 000 person years; P = 0.032). Using EULAR/ACR classification criteria, the largest IIM subtype (21/32) was PM, followed by DM (8/32), IBM (2/32) and amyopathic DM (1/32). Expert opinion subtype differed from EULAR/ACR classification criteria in 19/32 cases. CONCLUSION: The incidence of adult IIM in Salford is 17.6/1 000 000 person years, higher in females, and is increasing over time. Disagreement exists between EULAR/ACR-derived and expert opinion-derived IIM subtype assignments.

13.
BMC Rheumatol ; 1: 4, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-30886948

RESUMEN

BACKGROUND: The idiopathic inflammatory myopathies (IIM, myositis) are a heterogeneous group of chronic autoimmune disorders causing considerable physical and mental health impact. There is a lack of formalised guidance defining best practice for the management of myositis, contributing to inconsistent care provision and some patients feeling isolated and unsupported.To address these issues, we evaluated the clinical services available to adults with myositis in the UK. We then created patient-centred standards of care using a structured process involving patients, their relatives and caregivers, physicians and allied healthcare professionals. METHODS: After an initial focus group, the clinical services available to patients with myositis were evaluated using a patient-completed questionnaire. Draft standards of care were created, each addressing deficits in care provision identified by patients. In response to feedback, including a two-stage modified Delphi exercise, these draft standards were iteratively improved until consensus was reached. Accompanying plain language versions of the standards of care and an audit tool were also created. RESULTS: We identified issues regarding diagnostic pathways, access to specialist services, advice and support regarding employment, medication-related adverse events and the treatment of extra-muscular manifestations. Fifteen standards of care were drafted. After modification, agreement was reached on eleven final standards of care. CONCLUSION: These patient-centred standards of care for adults with myositis provide a benchmark for the evaluation of local practice. Their implementation will promote consistent good practice across care providers and empower patients when seeking access to local services.

14.
Chem Commun (Camb) ; 51(25): 5448-51, 2015 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-25731742

RESUMEN

For the purpose of realizing inherently safe high-power Li-ion batteries, a model Li4Ti5O12/LiFePO4 rechargeable battery is investigated using the thermally responsive polymer, poly(benzyl methacrylate), in an ionic liquid. At high temperature, battery operation is inhibited as a result of increased internal resistance caused by polymer and ionic liquid phase separation. Li-ion concentration is shown to affect the phase transition temperature and the extent to which batteries are deactivated.

15.
J Biomol Screen ; 18(10): 1246-59, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24108119

RESUMEN

Phenotypic screening seeks to identify substances that modulate phenotypes in a desired manner with the aim of progressing first-in-class agents. Successful campaigns require physiological relevance, robust screening, and an ability to deconvolute perturbed pathways. High-content analysis (HCA) is increasingly used in cell biology and offers one approach to prosecution of phenotypic screens, but challenges exist in exploitation where data generated are high volume and complex. We combine development of an organotypic model with novel HCA tools to map phenotypic responses to pharmacological perturbations. We describe implementation for angiogenesis, a process that has long been a focus for therapeutic intervention but has lacked robust models that recapitulate more completely mechanisms involved. The study used human primary endothelial cells in co-culture with stromal fibroblasts to model multiple aspects of angiogenic signaling: cell interactions, proliferation, migration, and differentiation. Multiple quantitative descriptors were derived from automated microscopy using custom-designed algorithms. Data were extracted using a bespoke informatics platform that integrates processing, statistics, and feature display into a streamlined workflow for building and interrogating fingerprints. Ninety compounds were characterized, defining mode of action by phenotype. Our approach for assessing phenotypic outcomes in complex assay models is robust and capable of supporting a range of phenotypic screens at scale.


Asunto(s)
Inhibidores de la Angiogénesis/farmacología , Evaluación Preclínica de Medicamentos/métodos , Células Cultivadas , Análisis por Conglomerados , Técnicas de Cocultivo , Ensayos Analíticos de Alto Rendimiento , Células Endoteliales de la Vena Umbilical Humana , Humanos , Análisis Multivariante , Neovascularización Patológica/tratamiento farmacológico , Fenotipo
16.
J Biomol Screen ; 18(10): 1321-9, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24045582

RESUMEN

Quantitative microscopy has proven a versatile and powerful phenotypic screening technique. Recently, image-based profiling has shown promise as a means for broadly characterizing molecules' effects on cells in several drug-discovery applications, including target-agnostic screening and predicting a compound's mechanism of action (MOA). Several profiling methods have been proposed, but little is known about their comparative performance, impeding the wider adoption and further development of image-based profiling. We compared these methods by applying them to a widely applicable assay of cultured cells and measuring the ability of each method to predict the MOA of a compendium of drugs. A very simple method that is based on population means performed as well as methods designed to take advantage of the measurements of individual cells. This is surprising because many treatments induced a heterogeneous phenotypic response across the cell population in each sample. Another simple method, which performs factor analysis on the cellular measurements before averaging them, provided substantial improvement and was able to predict MOA correctly for 94% of the treatments in our ground-truth set. To facilitate the ready application and future development of image-based phenotypic profiling methods, we provide our complete ground-truth and test data sets, as well as open-source implementations of the various methods in a common software framework.


Asunto(s)
Forma de la Célula/efectos de los fármacos , Evaluación Preclínica de Medicamentos/métodos , Análisis Factorial , Humanos , Células MCF-7 , Microscopía Fluorescente , Fenotipo , Bibliotecas de Moléculas Pequeñas , Máquina de Vectores de Soporte
17.
J Neurol Sci ; 325(1-2): 165-9, 2013 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-23273904

RESUMEN

Mitochondrial tRNA point mutations are important causes of human disease, and have been associated with a diverse range of clinical phenotypes. Definitively proving the pathogenicity of any given mt-tRNA mutation requires combined molecular, genetic and functional studies. Subsequent evaluation of the mutation using a pathogenicity scoring system is often very helpful in concluding whether or not the mutation is causing disease. Despite several independent reports linking the m.3291T>C mutation to disease in humans, albeit in association with several different phenotypes, its pathogenicity remains controversial. A lack of conclusive functional evidence and an over-emphasis on the poor evolutionary conservation of the affected nucleotide have contributed to this controversy. Here we describe an adult patient who presented with deafness and lipomas and evidence of mitochondrial abnormalities in his muscle biopsy, who harbours the m.3291T>C mutation, providing conclusive evidence of pathogenicity through analysis of mutation segregation with cytochrome c oxidase (COX) deficiency in single muscle fibres, underlining the importance of performing functional studies when assessing pathogenicity.


Asunto(s)
Enfermedades Mitocondriales/diagnóstico , Enfermedades Mitocondriales/genética , Mutación Puntual/genética , ARN de Transferencia de Leucina/genética , ARN/genética , Secuencia de Bases , Humanos , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , ARN Mitocondrial
18.
ACS Appl Mater Interfaces ; 4(11): 6247-51, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23130670

RESUMEN

Many reactions in both chemistry and biology rely on the ability to precisely control and fix the solution concentrations of either protons or hydroxide ions. In this report, we describe the behavior of thermally programmable pH buffer systems based on the copolymerization of varying amounts of acrylic acid (AA) groups into N-isopropylacrylamide polymers. Because the copolymers undergo phase transitions upon heating and cooling, the local environment around the AA groups can be reversibly switched between hydrophobic and hydrophilic states affecting the ionization behavior of the acids. Results show that moderate temperature variations can be used to change the solution pH by two units. However, results also indicate that the nature of the transition and its impact on the pH values are highly dependent on the AA content and the degree of neutralization.


Asunto(s)
Acrilamidas/química , Acrilatos/química , Calor , Concentración de Iones de Hidrógeno , Ensayo de Materiales , Transición de Fase
19.
Brain ; 135(Pt 11): 3392-403, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23107649

RESUMEN

Mutations in the nuclear-encoded mitochondrial maintenance gene RRM2B are an important cause of familial mitochondrial disease in both adults and children and represent the third most common cause of multiple mitochondrial DNA deletions in adults, following POLG [polymerase (DNA directed), gamma] and PEO1 (now called C10ORF2, encoding the Twinkle helicase) mutations. However, the clinico-pathological and molecular features of adults with RRM2B-related disease have not been clearly defined. In this multicentre study of 26 adult patients from 22 independent families, including five additional cases published in the literature, we show that extra-ocular neurological complications are common in adults with genetically confirmed RRM2B mutations. We also demonstrate a clear correlation between the clinical phenotype and the underlying genetic defect. Myopathy was a prominent manifestation, followed by bulbar dysfunction and fatigue. Sensorineural hearing loss and gastrointestinal disturbance were also important findings. Severe multisystem neurological disease was associated with recessively inherited compound heterozygous mutations with a mean age of disease onset at 7 years. Dominantly inherited heterozygous mutations were associated with a milder predominantly myopathic phenotype with a later mean age of disease onset at 46 years. Skeletal muscle biopsies revealed subsarcolemmal accumulation of mitochondria and/or cytochrome c oxidase-deficient fibres. Multiple mitochondrial DNA deletions were universally present in patients who underwent a muscle biopsy. We identified 18 different heterozygous RRM2B mutations within our cohort of patients, including five novel mutations that have not previously been reported. Despite marked clinical overlap between the mitochondrial maintenance genes, key clinical features such as bulbar dysfunction, hearing loss and gastrointestinal disturbance should help prioritize genetic testing towards RRM2B analysis, and sequencing of the gene may preclude performance of a muscle biopsy.


Asunto(s)
Proteínas de Ciclo Celular/genética , Eliminación de Gen , Miopatías Mitocondriales/diagnóstico , Miopatías Mitocondriales/genética , Enfermedades Neuromusculares/genética , Ribonucleótido Reductasas/genética , Adulto , Anciano , Anciano de 80 o más Años , Encefalopatías/complicaciones , Encefalopatías/genética , Estudios de Cohortes , Heterocigoto , Humanos , Persona de Mediana Edad , Miopatías Mitocondriales/complicaciones , Miopatías Mitocondriales/patología , Modelos Genéticos , Músculo Esquelético/patología , Mutación Missense/genética , Enfermedades Neuromusculares/complicaciones , Fenotipo
20.
Adv Mater ; 24(7): 886-9, 2012 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-22253076

RESUMEN

A thermally responsive copolymer is designed to modulate the properties of an electrolyte solution. The copolymer is prepared using pNIPAM, which governs the thermal properties, and acrylic acid, which provides the electrolyte ions. As the polymer undergoes a thermally activated phase transition, the local environment around the acid groups is reversibly switched, decreasing ion concentration and conductivity. The responsive electrolyte is used to control the activity of redox electrodes with temperature.


Asunto(s)
Electrólitos/química , Polímeros/química , Resinas Acrílicas/química , Técnicas Electroquímicas , Electrodos , Concentración de Iones de Hidrógeno , Oxidación-Reducción , Temperatura
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