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1.
Hum Mol Genet ; 31(9): 1417-1429, 2022 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-34761268

RESUMEN

The common null polymorphism (R577X) in the ACTN3 gene is present in over 1.5 billion people worldwide and results in the absence of the protein α-actinin-3 from the Z-discs of fast-twitch skeletal muscle fibres. We have previously reported that this polymorphism is a modifier of dystrophin-deficient Duchenne Muscular Dystrophy. To investigate the mechanism underlying this, we use a double knockout (dk)Actn3KO/mdx (dKO) mouse model, which lacks both dystrophin and sarcomere α-actinin-3. We used dKO mice and mdx dystrophic mice at 12 months (aged) to investigate the correlation between morphological changes to the fast-twitch dKO EDL and the reduction in force deficit produced by an in vitro eccentric contraction protocol. In the aged dKO mouse, we found a marked reduction in fibre branching complexity that correlated with protection from eccentric contraction induced force deficit. Complex branches in the aged dKO EDL fibres (28%) were substantially reduced compared to aged mdx EDL fibres (68%), and this correlates with a graded force loss over three eccentric contractions for dKO muscles (~36% after first contraction, ~66% overall) compared to an abrupt drop in mdx upon the first eccentric contraction (~75% after first contraction, ~89% after three contractions). In dKO, protection from eccentric contraction damage was linked with a doubling of SERCA1 pump density the EDL. We propose that the increased oxidative metabolism of fast-twitch glycolytic fibres characteristic of the null polymorphism (R577X) and increase in SR Ca2+ pump proteins reduces muscle fibre branching and decreases susceptibility to eccentric injury in the dystrophinopathies.


Asunto(s)
Distrofina , Distrofia Muscular de Duchenne , Actinina/genética , Actinina/metabolismo , Anciano , Animales , Distrofina/metabolismo , Humanos , Ratones , Ratones Endogámicos mdx , Contracción Muscular/genética , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Distrofia Muscular de Duchenne/metabolismo
2.
Crit Care ; 28(1): 254, 2024 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-39033135

RESUMEN

The endothelial glycocalyx, a gel-like layer that lines the luminal surface of blood vessels, is composed of proteoglycans, glycoproteins, and glycosaminoglycans. The endothelial glycocalyx plays an essential role in vascular homeostasis, and its degradation in trauma and sepsis can lead to microvascular dysfunction and organ injury. While there are no proven therapies for preventing or treating endothelial glycocalyx degradation, some initial literature suggests that plasma may have a therapeutic role in trauma and sepsis patients. Overall, the literature suggesting the use of plasma as a therapy for endothelial glycocalyx degradation is non-clinical basic science or exploratory. Plasma is an established therapy in the resuscitation of patients with hemorrhage for restoration of coagulation factors. However, plasma also contains other bioactive components, including sphingosine-1 phosphate, antithrombin, and adiponectin, which may protect and restore the endothelial glycocalyx, thereby helping to maintain or restore vascular homeostasis. This narrative review begins by describing the endothelial glycocalyx in health and disease: we discuss the overlapping disease mechanisms in trauma and sepsis that lead to its damage and introduce plasma transfusion as a potential therapy for prevention and treatment of endothelial glycocalyx degradation. Second, we review the literature on plasma as an exploratory therapy for endothelial glycocalyx degradation in trauma and sepsis. Third, we discuss the safety of plasma transfusion by reviewing the adverse events associated with plasma and other blood product transfusions, and we examine modern transfusion precautions that have enhanced the safety of plasma transfusion. We conclude that the literature proposes that plasma may have the potential to prevent and treat endothelial glycocalyx degradation in trauma and sepsis, indicating the need for further research.


Asunto(s)
Glicocálix , Plasma , Sepsis , Heridas y Lesiones , Glicocálix/metabolismo , Glicocálix/fisiología , Humanos , Sepsis/terapia , Sepsis/fisiopatología , Heridas y Lesiones/terapia , Heridas y Lesiones/complicaciones , Plasma/metabolismo , Endotelio Vascular/metabolismo , Endotelio Vascular/fisiopatología
3.
N Engl J Med ; 382(12): 1093-1102, 2020 03 19.
Artículo en Inglés | MEDLINE | ID: mdl-32187469

RESUMEN

BACKGROUND: The treatment of chronic sciatica caused by herniation of a lumbar disk has not been well studied in comparison with acute disk herniation. Data are needed on whether diskectomy or a conservative approach is better for sciatica that has persisted for several months. METHODS: In a single-center trial, we randomly assigned patients with sciatica that had lasted for 4 to 12 months and lumbar disk herniation at the L4-L5 or L5-S1 level in a 1:1 ratio to undergo microdiskectomy or to receive 6 months of standardized nonoperative care followed by surgery if needed. Surgery was performed by spine surgeons who used conventional microdiskectomy techniques. The primary outcome was the intensity of leg pain on a visual analogue scale (ranging from 0 to 10, with higher scores indicating more severe pain) at 6 months after enrollment. Secondary outcomes were the score on the Oswestry Disability Index, back and leg pain, and quality-of-life scores at 6 weeks, 3 months, 6 months, and 1 year. RESULTS: From 2010 through 2016, a total of 790 patients were screened; of those patients, 128 were enrolled, with 64 in each group. Among the patients assigned to undergo surgery, the median time from randomization to surgery was 3.1 weeks; of the 64 patients in the nonsurgical group, 22 (34%) crossed over to undergo surgery at a median of 11 months after enrollment. At baseline, the mean score for leg-pain intensity was 7.7 in the surgical group and 8.0 in the nonsurgical group. The primary outcome of the leg-pain intensity score at 6 months was 2.8 in the surgical group and 5.2 in the nonsurgical group (adjusted mean difference, 2.4; 95% confidence interval, 1.4 to 3.4; P<0.001). Secondary outcomes including the score on the Owestry Disability Index and pain at 12 months were in the same direction as the primary outcome. Nine patients had adverse events associated with surgery, and one patient underwent repeat surgery for recurrent disk herniation. CONCLUSIONS: In this single-center trial involving patients with sciatica lasting more than 4 months and caused by lumbar disk herniation, microdiskectomy was superior to nonsurgical care with respect to pain intensity at 6 months of follow-up. (Funded by Physicians' Services Incorporated Foundation; ClinicalTrials.gov number, NCT01335646.).


Asunto(s)
Tratamiento Conservador , Discectomía , Glucocorticoides/administración & dosificación , Desplazamiento del Disco Intervertebral/cirugía , Modalidades de Fisioterapia , Ciática/terapia , Adulto , Tratamiento Conservador/métodos , Estudios Cruzados , Discectomía/efectos adversos , Femenino , Estudios de Seguimiento , Humanos , Inyecciones Epidurales , Análisis de Intención de Tratar , Desplazamiento del Disco Intervertebral/complicaciones , Desplazamiento del Disco Intervertebral/tratamiento farmacológico , Masculino , Dolor/etiología , Dimensión del Dolor , Satisfacción del Paciente , Complicaciones Posoperatorias , Calidad de Vida , Ciática/etiología , Ciática/cirugía , Resultado del Tratamiento
4.
J Biomech Eng ; 145(1)2023 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-35864783

RESUMEN

This note considers the mathematical model published in the Journal of Biomechanical Engineering by McKee et al. [McKee, S., Cuminato, J. A., Stewart, I. W., and Wheatley, D. J., 2021, "A Mathematical Representation of the Wheatley Heart Valve," ASME J. Biomech. Eng., 143(8), p. 081006]. The model presented there suffers from the fact that there is a line discontinuity in the first derivative producing what appears to be a kink in each of the leaflets. This note is concerned with regularizing the shape of the valve while holding to Wheatley's essential idea [Wheatley, D. J., 2016, "Heart Valve," U.S. Patent No. 9,259,313, UK Patent No. 2,982,340 (2017), European Patent No. 2,979,666 (2017)].


Asunto(s)
Válvulas Cardíacas , Modelos Biológicos , Ingeniería Biomédica
5.
J Happiness Stud ; 24(8): 2441-2472, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38130904

RESUMEN

PERMA is a multidimensional framework that explains well-being through five hedonic and eudaimonic psychological elements-Positive emotions, Engagement, Relationships, Meaning, Accomplishment. Soon after the PERMA framework was proposed, PERMA-Profiler was introduced as a validated assessment tool for measuring these five elements of well-being from a global perspective. The current study aimed to shed further light onto the measurement of PERMA elements, extending it beyond global evaluations, to daily life assessments and the examination of individual differences in their dynamic characteristics. We introduce mPERMA (momentary PERMA), as an EMA-adapted version of the PERMA-Profiler measure, to assess well-being in daily life. Using data collected in an Ecological Momentary Assessment (EMA) study (N = 160), we first demonstrate the factor structure of mPERMA through a multilevel factor analysis and next examine within-person means and the dynamics of change (e.g., intra-individual variability) in the PERMA elements. Findings revealed that mPERMA displays convergent validity with two global measures of hedonic and eudaimonic well-being, namely Flourishing and Subjective Well-Being. Moreover, dynamical characteristics of the five elements of well-being measured over time, map onto their corresponding hedonic or eudaimonic global measures of well-being. Results of this paper present how dynamical features of well-being in daily life provide novel insights into predicting global well-being. Supplementary Information: The online version contains supplementary material available at 10.1007/s10902-023-00684-w.

6.
J Muscle Res Cell Motil ; 43(4): 173-183, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-35987933

RESUMEN

The single freshly skinned muscle fibre technique was used to investigate Ca2+- and Sr2+-activation properties of skeletal muscle fibres from elderly women (66-90 years). Muscle biopsies were obtained from the vastus lateralis muscle. Three populations of muscle fibres were identified according to their specific Sr2+-activation properties: slow-twitch (type I), fast-twitch (type II) and hybrid (type I/II) fibres. All three fibre types were sampled from the biopsies of 66 to 72 years old women, but the muscle biopsies of women older than 80 years yielded only slow-twitch (type I) fibres. The proportion of hybrid fibres in the vastus lateralis muscle of women of circa 70 years of age (24%) was several-fold greater than in the same muscle of adults (< 10%), suggesting that muscle remodelling occurs around this age. There were no differences between the Ca2+- and Sr2+-activation properties of slow-twitch fibres from the two groups of elderly women, but there were differences compared with muscle fibres from young adults with respect to sensitivity to Ca2+, steepness of the activation curves, and characteristics of the fibre-type dependent phenomenon of spontaneous oscillatory contractions (SPOC) (or force oscillations) occurring at submaximal levels of activation. The maximal Ca2+ activated specific force from all the fibres collected from the seven old women use in the present study was significantly lower by 20% than in the same muscle of adults. Taken together these results show there are qualitative and quantitative changes in the activation properties of the contractile apparatus of muscle fibres from the vastus lateralis muscle of women with advancing age, and that these changes need to be considered when explaining observed changes in women's mobility with aging.


Asunto(s)
Calcio , Estroncio , Adulto Joven , Humanos , Femenino , Anciano , Contracción Muscular/fisiología , Fibras Musculares Esqueléticas , Envejecimiento/fisiología , Músculo Esquelético
7.
Exp Physiol ; 107(6): 601-614, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35471703

RESUMEN

NEW FINDINGS: What is the central question of this study? What are the early effects of dystrophin deficiency on sarcoplasmic reticulum Ca2+ handling in the mdx mouse? What is the main finding and its importance? In the mdx mouse, Ca2+ handling by the sarcoplasmic reticulum is little affected by the absence of dystrophin when looking at fibres without branches that have recently regenerated after massive myonecrosis. This has important implications for our understanding of Ca2+ pathology in the mdx mouse. ABSTRACT: There is a variety of results in the literature regarding the effects of dystrophin deficiency on the Ca2+ handling properties of the sarcoplasmic reticulum (SR) in the mdx mouse, an animal model of Duchenne muscular dystrophy. One possible source of variation is the presence of branched fibres. Fibre branching, a consequence of degenerative-regenerative processes such as muscular dystrophy, has in itself a significant influence on the function of the SR. In this study, we attempted to detect early effects of dystrophin deficiency on SR Ca2+ handling by using unbranched fibres from the immediate post-necrotic stage in mdx mice (recently regenerated after massive necrosis). Using kinetically corrected fura-2 fluorescence signals measured during twitch and tetanus, we analysed the amplitude, rise time and decay time of Δ[Ca2+ ]i in unfatigued and fatigued fibres. Decay was also resolved into SR pump and SR leak components. Fibres from mdx mice were similar in all respects to fibres from wild-type littermates apart from: (1) a smaller amplitude of the initial spike of Δ[Ca2+ ]i during a tetanus; and (2) a mitigation of the fall in Δ[Ca2+ ]i amplitude during the course of fatigue. Our findings suggest that the early effects of a loss of dystrophin on SR Ca2+ handling in mdx mice are subtle, and we emphasize the importance of distinguishing between Ca2+ pathology that is attributable to lack of dystrophin and Ca2+ pathology that is attributable to muscle degeneration.


Asunto(s)
Distrofia Muscular de Duchenne , Tétanos , Animales , Calcio , Distrofina , Ratones , Ratones Endogámicos mdx , Fibras Musculares Esqueléticas/fisiología , Distrofia Muscular de Duchenne/patología , Retículo Sarcoplasmático , Tétanos/patología
8.
Clin Orthop Relat Res ; 480(3): 574-584, 2022 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-34597280

RESUMEN

BACKGROUND: A recent randomized controlled trial (RCT), performed by the authors, comparing early surgical microdiscectomy with 6 months of nonoperative care for chronic lumbar radiculopathy showed that early surgery resulted in improved outcomes. However, estimates of the incremental cost-utility ratio (ICUR), which is often expressed as the cost of gaining one quality-adjusted life year (QALY), of microdiscectomy versus nonsurgical management have varied. Radiculopathy lasting more than 4 months is less likely to improve without surgical intervention and may have a more favorable ICUR than previously reported for acute radiculopathy. QUESTION/PURPOSE: In the setting of chronic radiculopathy caused by lumbar disc herniation, defined as symptoms and/or signs of 4 to 12 months duration, is surgical management more cost-effective than 6 months of nonoperative care from the third-party payer perspective based on a willingness to pay of less than CAD 50,000/QALY? METHODS: A decision analysis model served as the vehicle for the cost-utility analysis. A decision tree was parameterized using data from our single-center RCT that was augmented with institutional microcost data from the Ontario Case Costing Initiative. Bottom-up case costing methodology generates more accurate cost estimates, although institutional costs are known to vary. There were no major surgical cost drivers such as implants or bone graft substitutes, and therefore, the jurisdictional variance would be minimal for tertiary care centers. QALYs derived from the EuroQoL-5D were the health outcome and were derived exclusively from the RCT data, given the paucity of studies evaluating the surgical treatment of lumbar radiculopathy lasting 4 to 12 months. Cost-effectiveness was assessed using the ICUR and a threshold of willingness to pay CAD 50,000 (USD 41,220) per QALY in the base case. Sensitivity analyses were performed to account for the uncertainties within the estimate of cost utility, using both a probabilistic sensitivity analysis and two one-way sensitivity analyses with varying crossover rates after the 6-month nonsurgical treatment had concluded. RESULTS: Early surgical treatment of patients with chronic lumbar radiculopathy (defined as symptoms of 4 to 12 months duration) was cost-effective, in that the cost of one QALY was lower than the CAD 50,000 threshold (note: the purchasing power parity conversion factor between the Canadian dollar (CAD) and the US dollar (USD) for 2019 was 1 USD = 1.213 CAD; therefore, our threshold was USD 41,220). Patients in the early surgical treatment group had higher expected costs (CAD 4118 [95% CI 3429 to 4867]) than those with nonsurgical treatment (CAD 2377 [95% CI 1622 to 3518]), but they had better expected health outcomes (1.48 QALYs [95% CI 1.39 to 1.57] versus 1.30 [95% CI 1.22 to 1.37]). The ICUR was CAD 5822 per QALY gained (95% CI 3029 to 30,461). The 2-year probabilistic sensitivity analysis demonstrated that the likelihood that early surgical treatment was cost-effective was 0.99 at the willingness-to-pay threshold, as did the one-way sensitivity analyses. CONCLUSION: Early surgery is cost-effective compared with nonoperative care in patients who have had chronic sciatica for 4 to 12 months. Decision-makers should ensure adequate funding to allow timely access to surgical care given that it is highly likely that early surgical intervention is potentially cost-effective in single-payer systems. Future work should focus on both the clinical effectiveness of the treatment of chronic radiculopathy and the costs of these treatments from a societal perspective to account for occupational absences and lost patient productivity. Parallel cost-utility analyses are critical so that appropriate decisions about resource allocation can be made. LEVEL OF EVIDENCE: Level III, economic and decision analysis.


Asunto(s)
Discectomía/economía , Desplazamiento del Disco Intervertebral/economía , Desplazamiento del Disco Intervertebral/terapia , Microcirugia/economía , Modalidades de Fisioterapia/economía , Radiculopatía/economía , Radiculopatía/terapia , Adulto , Análisis Costo-Beneficio , Discectomía/métodos , Femenino , Humanos , Vértebras Lumbares , Masculino , Microcirugia/métodos , Persona de Mediana Edad , Dimensión del Dolor , Calidad de Vida , Años de Vida Ajustados por Calidad de Vida
9.
Am J Physiol Cell Physiol ; 321(4): C704-C720, 2021 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-34432537

RESUMEN

Duchenne muscular dystrophy (DMD) is the second most common fatal genetic disease in humans and is characterized by the absence of a functional copy of the protein dystrophin from skeletal muscle. In dystrophin-negative humans and rodents, regenerated skeletal muscle fibers show abnormal branching. The number of fibers with branches and the complexity of branching increases with each cycle of degeneration/regeneration. Previously, using the mdx mouse model of DMD, we have proposed that once the number and complexity of branched fibers present in dystrophic fast-twitch EDL muscle surpasses a stable level, we term the "tipping point," the branches, in and of themselves, mechanically weaken the muscle by rupturing when subjected to high forces during eccentric contractions. Here, we use the slow-twitch soleus muscle from the dystrophic mdx mouse to study prediseased "periambulatory" dystrophy at 2-3 wk, the peak regenerative "adult" phase at 6-9 wk, and "old" at 58-112 wk. Using isolated mdx soleus muscles, we examined contractile function and response to eccentric contraction correlated with the amount and complexity of regenerated branched fibers. The intact muscle was enzymatically dispersed into individual fibers in order to count fiber branching and some muscles were optically cleared to allow laser scanning confocal microscopy. We demonstrate throughout the lifespan of the mdx mouse that dystrophic slow-twitch soleus muscle is no more susceptible to eccentric contraction-induced injury than age-matched littermate controls and that this is correlated with a reduction in the number and complexity of branched fibers compared with fast-twitch dystrophic EDL muscles.


Asunto(s)
Distrofina/deficiencia , Contracción Muscular , Fibras Musculares de Contracción Rápida/metabolismo , Fibras Musculares de Contracción Lenta/metabolismo , Distrofia Muscular de Duchenne/metabolismo , Factores de Edad , Animales , Modelos Animales de Enfermedad , Distrofina/genética , Cinética , Masculino , Ratones Endogámicos mdx , Fibras Musculares de Contracción Rápida/patología , Fibras Musculares de Contracción Lenta/patología , Fuerza Muscular , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/patología , Distrofia Muscular de Duchenne/fisiopatología , Mutación
10.
Am J Hum Genet ; 102(5): 845-857, 2018 05 03.
Artículo en Inglés | MEDLINE | ID: mdl-29706347

RESUMEN

Loss of expression of ACTN3, due to homozygosity of the common null polymorphism (p.Arg577X), is underrepresented in elite sprint/power athletes and has been associated with reduced muscle mass and strength in humans and mice. To investigate ACTN3 gene dosage in performance and whether expression could enhance muscle force, we performed meta-analysis and expression studies. Our general meta-analysis using a Bayesian random effects model in elite sprint/power athlete cohorts demonstrated a consistent homozygous-group effect across studies (per allele OR = 1.4, 95% CI 1.3-1.6) but substantial heterogeneity in heterozygotes. In mouse muscle, rAAV-mediated gene transfer overexpressed and rescued α-actinin-3 expression. Contrary to expectation, in vivo "doping" of ACTN3 at low to moderate doses demonstrated an absence of any change in function. At high doses, ACTN3 is toxic and detrimental to force generation, to demonstrate gene doping with supposedly performance-enhancing isoforms of sarcomeric proteins can be detrimental for muscle function. Restoration of α-actinin-3 did not enhance muscle mass but highlighted the primary role of α-actinin-3 in modulating muscle metabolism with altered fatiguability. This is the first study to express a Z-disk protein in healthy skeletal muscle and measure the in vivo effect. The sensitive balance of the sarcomeric proteins and muscle function has relevant implications in areas of gene doping in performance and therapy for neuromuscular disease.


Asunto(s)
Actinina/genética , Músculo Esquelético/fisiología , Anaerobiosis , Animales , Animales Recién Nacidos , Atletas , Calcineurina/metabolismo , Dependovirus/metabolismo , Regulación hacia Abajo/genética , Estudio de Asociación del Genoma Completo , Heterocigoto , Homocigoto , Humanos , Ratones Endogámicos C57BL , Fatiga Muscular , Fibras Musculares Esqueléticas/metabolismo , Tamaño de los Órganos , Oxidación-Reducción
11.
J Biomech Eng ; 143(8)2021 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-33817747

RESUMEN

Starting from a hand-drawn contour plot, this note develops a set of intersecting and contiguous circles whose perimeter, upon extending appropriately to three dimensions, can be seen to be a natural mathematical representation of the Wheatley heart valve.


Asunto(s)
Válvulas Cardíacas
12.
Am J Physiol Cell Physiol ; 314(6): C662-C674, 2018 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-29412689

RESUMEN

A striking pathological feature of dystrophinopathies is the presence of morphologically abnormal branched skeletal muscle fibers. The deterioration of muscle contractile function in Duchenne muscular dystrophy is accompanied by both an increase in number and complexity of these branched fibers. We propose that when number and complexity of branched fibers reaches a critical threshold, or "tipping point," the branches in and of themselves are the site of contraction-induced rupture. In the present study, we use the dystrophic mdx mouse and littermate controls to study the prediseased dystrophic fast-twitch extensor digitorum longus (EDL) muscle at 2-3 wk, the peak myonecrotic phase at 6-9 wk, and finally, "old," at 58-112 wk. Using a combination of isolated muscle function contractile measurements coupled with single-fiber imaging and confocal microscope imaging of cleared whole muscles, we identified a distinct pathophysiology, acute fiber rupture at branch nodes, which occurs in "old" fast-twitch EDL muscle approaching the end stage of the dystrophinopathy muscle disease, where the EDL muscles are entirely composed of complexed branched fibers. This evidence supports our concept of "tipping point" where the number and extent of fiber branching reach a level where the branching itself terminally compromises muscle function, irrespective of the absence of dystrophin.


Asunto(s)
Fibras Musculares de Contracción Rápida/patología , Músculo Esquelético/patología , Distrofia Muscular de Duchenne/patología , Factores de Edad , Animales , Modelos Animales de Enfermedad , Estimulación Eléctrica , Contracción Isométrica , Cinética , Masculino , Ratones Endogámicos C57BL , Ratones Endogámicos mdx , Microscopía Confocal , Fuerza Muscular , Músculo Esquelético/fisiopatología , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/fisiopatología , Necrosis , Análisis de la Célula Individual
13.
Hum Mol Genet ; 25(5): 866-77, 2016 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-26681802

RESUMEN

A common null polymorphism (R577X) in ACTN3 causes α-actinin-3 deficiency in ∼ 18% of the global population. There is no associated disease phenotype, but α-actinin-3 deficiency is detrimental to sprint and power performance in both elite athletes and the general population. However, despite considerable investigation to date, the functional consequences of heterozygosity for ACTN3 are unclear. A subset of studies have shown an intermediate phenotype in 577RX individuals, suggesting dose-dependency of α-actinin-3, while others have shown no difference between 577RR and RX genotypes. Here, we investigate the effects of α-actinin-3 expression level by comparing the muscle phenotypes of Actn3(+/-) (HET) mice to Actn3(+/+) [wild-type (WT)] and Actn3(-/-) [knockout (KO)] littermates. We show reduction in α-actinin-3 mRNA and protein in HET muscle compared with WT, which is associated with dose-dependent up-regulation of α-actinin-2, z-band alternatively spliced PDZ-motif and myotilin at the Z-line, and an incremental shift towards oxidative metabolism. While there is no difference in force generation, HET mice have an intermediate endurance capacity compared with WT and KO. The R577X polymorphism is associated with changes in ACTN3 expression consistent with an additive model in the human genotype-tissue expression cohort, but does not influence any other muscle transcripts, including ACTN2. Overall, ACTN3 influences sarcomeric composition in a dose-dependent fashion in mouse skeletal muscle, which translates directly to function. Variance in fibre type between biopsies likely masks this phenomenon in human skeletal muscle, but we suggest that an additive model is the most appropriate for use in testing ACTN3 genotype associations.


Asunto(s)
Actinina/genética , Dosificación de Gen , Músculo Esquelético/metabolismo , Resistencia Física/genética , Polimorfismo Genético , Actinina/deficiencia , Actinina/metabolismo , Animales , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Heterocigoto , Homocigoto , Humanos , Masculino , Ratones , Ratones Noqueados , Proteínas de Microfilamentos , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Condicionamiento Físico Animal , Sarcómeros/metabolismo
14.
PLoS Genet ; 11(2): e1004862, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25590636

RESUMEN

Over 1.5 billion people lack the skeletal muscle fast-twitch fibre protein α-actinin-3 due to homozygosity for a common null polymorphism (R577X) in the ACTN3 gene. α-Actinin-3 deficiency is detrimental to sprint performance in elite athletes and beneficial to endurance activities. In the human genome, it is very difficult to find single-gene loss-of-function variants that bear signatures of positive selection, yet intriguingly, the ACTN3 null variant has undergone strong positive selection during recent evolution, appearing to provide a survival advantage where food resources are scarce and climate is cold. We have previously demonstrated that α-actinin-3 deficiency in the Actn3 KO mouse results in a shift in fast-twitch fibres towards oxidative metabolism, which would be more "energy efficient" in famine, and beneficial to endurance performance. Prolonged exposure to cold can also induce changes in skeletal muscle similar to those observed with endurance training, and changes in Ca2+ handling by the sarcoplasmic reticulum (SR) are a key factor underlying these adaptations. On this basis, we explored the effects of α-actinin-3 deficiency on Ca2+ kinetics in single flexor digitorum brevis muscle fibres from Actn3 KO mice, using the Ca2+-sensitive dye fura-2. Compared to wild-type, fibres of Actn3 KO mice showed: (i) an increased rate of decay of the twitch transient; (ii) a fourfold increase in the rate of SR Ca2+ leak; (iii) a threefold increase in the rate of SR Ca2+ pumping; and (iv) enhanced maintenance of tetanic Ca2+ during fatigue. The SR Ca2+ pump, SERCA1, and the Ca2+-binding proteins, calsequestrin and sarcalumenin, showed markedly increased expression in muscles of KO mice. Together, these changes in Ca2+ handling in the absence of α-actinin-3 are consistent with cold acclimatisation and thermogenesis, and offer an additional explanation for the positive selection of the ACTN3 577X null allele in populations living in cold environments during recent evolution.


Asunto(s)
Actinina/genética , Evolución Biológica , Calcio/metabolismo , Enfermedades Musculares/genética , Selección Genética , Aclimatación/genética , Actinina/deficiencia , Animales , Frío , Humanos , Cinética , Masculino , Ratones , Ratones Noqueados , Mitocondrias/genética , Mitocondrias/metabolismo , Mitocondrias/patología , Fibras Musculares de Contracción Rápida/metabolismo , Fibras Musculares de Contracción Rápida/patología , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Enfermedades Musculares/metabolismo , Enfermedades Musculares/patología , Polimorfismo Genético , Tiempo (Meteorología)
15.
Pharm Biol ; 56(1): 485-494, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30303034

RESUMEN

CONTEXT: Plants of the genus Echinacea (Asteraceae) are among the most popular herbal supplements on the market today. Recent studies indicate there are potential new applications and emerging markets for this natural health product (NHP). OBJECTIVE: This review aims to synthesize recent developments in Echinacea biotechnology and to identify promising applications for these advances in the industry. METHODS: A comprehensive survey of peer-reviewed publications was carried out, focusing on Echinacea biotechnology and impacts on phytochemistry. This article primarily covers research findings since 2007 and builds on earlier reviews on the biotechnology of Echinacea. RESULTS: Bioreactors, genetic engineering and controlled biotic or abiotic elicitation have the potential to significantly improve the yield, consistency and overall quality of Echinacea products. Using these technologies, a variety of new applications for Echinacea can be realized, such as the use of seed oil and antimicrobial and immune boosting feed additives for livestock. CONCLUSIONS: New applications can take advantage of the well-established popularity of Echinacea as a NHP. Echinacea presents a myriad of potential health benefits, including anti-inflammatory, anxiolytic and antibiotic activities that have yet to be fully translated into new applications. The distinct chemistry and bioactivity of different Echinacea species and organs, moreover, can lead to interesting and diverse commercial opportunities.


Asunto(s)
Biotecnología/tendencias , Echinacea , Extractos Vegetales/aislamiento & purificación , Extractos Vegetales/uso terapéutico , Transferencia de Tecnología , Animales , Antiinflamatorios/aislamiento & purificación , Antiinflamatorios/farmacología , Antiinflamatorios/uso terapéutico , Biotecnología/métodos , Predicción , Humanos , Inflamación/tratamiento farmacológico , Fitoquímicos/aislamiento & purificación , Fitoquímicos/farmacología , Fitoquímicos/uso terapéutico , Extractos Vegetales/farmacología
16.
Bioinformatics ; 30(8): 1177-1179, 2014 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-24403537

RESUMEN

MOTIVATION: Quantification of the contribution of genetic variation to phenotypic variation for complex traits becomes increasingly computationally demanding with increasing numbers of single-nucleotide polymorphisms and individuals. To meet the challenges in making feasible large-scale studies, we present the REgional heritability advanced complex trait analysis software. Adapted from advanced complex trait analysis (and, in turn, genome-wide complex trait analysis), it is tailored to exploit the parallelism present in modern traditional and graphics processing unit (GPU)-accelerated machines, from workstations to supercomputers. RESULTS: We adapt the genetic relationship matrix estimation algorithm to remove limitations on memory, allowing the analysis of large datasets. We build on this to develop a version of the code able to efficiently exploit GPU-accelerated systems for both the genetic relationship matrix and REstricted maximum likelihood (REML) parts of the analysis, offering substantial speedup over the traditional central processing unit version. We develop the ability to analyze multiple small regions of the genome across multiple compute nodes in parallel, following the 'regional heritability' approach. We demonstrate the new software using 1024 GPUs in parallel on one of the world's fastest supercomputers. AVAILABILITY: The code is freely available at http://www.epcc.ed.ac.uk/software-products CONTACT: a.gray@ed.ac.uk.


Asunto(s)
Fenotipo , Polimorfismo de Nucleótido Simple , Programas Informáticos , Algoritmos , Biología Computacional , Funciones de Verosimilitud
17.
Dysphagia ; 30(6): 723-9, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26376918

RESUMEN

The aim of this prospective, consecutive, cohort study was to investigate the biomechanical effects, if any, of the Blom low profile voice inner cannula and Passy-Muir one-way tracheotomy tube speaking valves on movement of the hyoid bone and larynx during swallowing. Ten adult patients (8 male, 2 female) with an age range of 61-89 years (mean 71 years) participated. Criteria for inclusion were ≥18 years of age, English speaking, and ability to tolerate both changing to a Blom tracheotomy tube and placement of a one-way tracheotomy tube speaking valve with a fully deflated tracheotomy tube cuff. Digitized videofluoroscopic swallow studies were performed at 30 frames/s and with each patient seated upright in the lateral plane. A total of 18 swallows (three each with 5 cc bolus volumes of single contrast barium and puree + barium × 3 conditions) were analyzed for each participant. Variables evaluated included larynx-to-hyoid bone excursion (mm), maximum hyoid bone displacement (mm), and aspiration status under three randomized conditions: 1. Tracheotomy tube open with no inner cannula; 2. Tracheotomy tube with Blom valve; and 3. Tracheotomy tube with Passy-Muir valve. Blinded reliability testing with a Pearson product moment correlation was performed on 20 % of the data. Intra- and inter-rater reliability for combined measurements of larynx-to-hyoid bone excursion and maximum hyoid bone displacement was r = 0.98. Intra- and inter-rater reliability for aspiration status was 100 %. No significant differences (p > 0.05) were found for larynx-to-hyoid bone excursion and maximum hyoid bone displacement during swallowing based upon an open tracheotomy tube, Blom valve, or Passy-Muir valve. Aspiration status was identical for all three randomized conditions. The presence of a one-way tracheotomy tube speaking valve did not significantly alter two important components of normal pharyngeal swallow biomechanics, i.e., hyoid bone and laryngeal movements. Aspiration status was similarly unaffected by valve use. Clinicians should be aware that the data do not support placement of a one-way tracheotomy tube speaking valve to reduce prandial aspiration.


Asunto(s)
Cánula , Deglución/fisiología , Hueso Hioides/fisiopatología , Intubación Intratraqueal/instrumentación , Laringe/fisiopatología , Traqueotomía/métodos , Calidad de la Voz/fisiología , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos , Trastornos de Deglución/fisiopatología , Trastornos de Deglución/rehabilitación , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Reproducibilidad de los Resultados
18.
Conn Med ; 78(2): 85-9, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24741857

RESUMEN

We report a case of atypical mycobacterium infection in a Warthin's tumor which occurred in a 79-year-old man. The patient had along history of a left parotid mass that underwent rapid growth, became painful, and fistulized. The patient underwent left parotidectomy and neck dissection which showed a Warthin's tumor with areas of necrotizing granulomas. Subsequent culture showed the growth of acid fast bacilli. Consideration of an underlying mycobacterium infection, although rare, is important due to the public health concerns and other treatment needs that such a diagnosis raises.


Asunto(s)
Adenolinfoma/complicaciones , Adenolinfoma/diagnóstico , Tuberculosis/complicaciones , Tuberculosis/diagnóstico , Anciano , Humanos , Masculino
19.
Public Health Rep ; 139(1): 129-137, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37057393

RESUMEN

OBJECTIVES: Program evaluation is an essential function for public health professionals that is necessary to acquire funding for public health programs and support evidenced-based practice, but coverage of program evaluation principles and methodology within the master of public health (MPH) curriculum is inconsistent and may not adequately prepare students to conduct program evaluation activities postgraduation, especially on culturally responsive program evaluation. We examined the effectiveness of an online training course on program evaluation topics. METHODS: In July 2021, we recruited current and recently graduated MPH students from accredited US universities to measure the effectiveness of a 1-hour online training course in program evaluation. We distributed pre- and postsurveys to eligible participants. We assessed program evaluation skills on a 4-point Likert scale to determine improvements in knowledge (from 4 = extremely knowledgeable to 1 = not knowledgeable), attitudes (from 4 = strongly agree to 1 = strongly disagree), and self-efficacy (from 4 = strongly agree to 1 = strongly disagree). RESULTS: Among 80 MPH students who completed the survey, respondents indicated mean (SD) increases from presurvey to postsurvey in knowledge (from 2.13 [0.66] to 3.24 [0.54]) and attitudes (from 3.61 [0.51] to 3.84 [0.30]) toward program evaluation and in self-efficacy in conducting program evaluation (from 2.92 [0.71] to 3.44 [0.52]). CONCLUSION: The course may be an effective approach for training public health professionals about program evaluation. Our results provide a basis for revising the way program evaluation is taught and practical recommendations for integrating program evaluation competencies within public health curricula, such as by incorporating a self-paced training course for continuing education.


Asunto(s)
Curriculum , Salud Pública , Humanos , Salud Pública/educación , Evaluación de Programas y Proyectos de Salud , Estudiantes , Universidades , Escuelas de Salud Pública
20.
J Am Coll Health ; : 1-8, 2024 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-38227924

RESUMEN

Objective: The study sought to test whether well-being predicts academic performance for student service members/veterans (SSM/Vs) and to assess the factor structure of the PERMA + 4 measurement scale for use in this student population. Participants: Post-9/11 SSM/Vs (N = 199) from seven colleges and universities in the U.S. completed an online survey. Methods: A cross-sectional survey research design was used to assess PERMA + 4 and academic success. The PERMA + 4 framework and the measurement scale were examined using confirmatory factor analysis (CFA), and logistic regressions to determine if PERMA + 4 predicted academic performance in SSM/Vs. Results: Findings indicate that PERMA + 4 is a predictor of SSM/Vs academic performance, and CFA confirmed the factor structure of PERMA + 4 for use with SSM/Vs. Conclusions: The findings suggest that screening for the building blocks of well-being in SSM/Vs with a validated and comprehensive multidimensional instrument could be useful for mitigating transition challenges into college life and informing appropriate supports.

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