RESUMEN

The outer membrane is the defining structure of Gram-negative bacteria. We previously demonstrated that it is critical for the mechanical integrity of the cell envelope and therefore to the robustness of the bacterial cell as a whole. Here, to determine the key molecules and moieties within the outer membrane that underlie its contribution to cell envelope mechanics, we measured cell-envelope stiffness across several sets of mutants with altered outer-membrane sugar content, protein content, and electric charge. To decouple outer membrane stiffness from total cell envelope stiffness, we developed a novel microfluidics-based "osmotic force extension" assay. In tandem, we developed a simple method to increase throughput of microfluidics experiments by performing them on color-coded pools of mutants. Using Escherichia coli as a model Gram-negative bacterium, we found that truncating the core oligosaccharide, deleting the ß-barrel protein OmpA, or deleting lipoprotein outer membrane-cell wall linkers all had the same modest, convergent effect on total cell-envelope stiffness but had large, varying effects on the ability of the cell wall to transfer tension to the outer membrane during large hyperosmotic shocks. Surprisingly, altering lipid A charge had little effect on the mechanical properties of the envelope. Importantly, the presence or absence of OmpA determined whether truncating the core oligosaccharide decreased or increased envelope stiffness (respectively), revealing sign epistasis between these components. Based on these data we propose a specific structural model in which the chemical interactions between lipopolysaccharides, ß-barrel proteins, and phospholipids coordinately determine cell envelope stiffness, and the ability of the outer membrane to functionally share mechanical loads with the cell wall. Statement of Significance: The outer membrane is the defining cellular structure of Gram-negative bacteria, a group that contains many important pathogens like Escherichia coli, Vibrio cholerae, and Pseudomonas aeruginosa. One role of the outer membrane is to block the uptake of small molecules like antibiotics. However, it is becoming increasingly clear that it also functions as a structural exoskeleton that is critical for the cell's ability to cope with internal and external mechanical forces. Here, we carefully dissect the molecular basis for the load-bearing capacity of the outer membrane by screening a set of mutants with a new cell biophysics assay.

RESUMEN

Diabetes mellitus and metabolic syndrome are closely linked with visceral body composition, but clinical assessment is limited to external measurements and laboratory values including hemoglobin A1c (HbA1c). Modern deep learning and AI algorithms allow automated extraction of biomarkers for organ size, density, and body composition from routine computed tomography (CT) exams. Comparing visceral CT biomarkers across groups with differing glycemic control revealed significant, progressive CT biomarker changes with increasing HbA1c. For example, in the unenhanced female cohort, mean changes between normal and poorly-controlled diabetes showed: 53% increase in visceral adipose tissue area, 22% increase in kidney volume, 24% increase in liver volume, 6% decrease in liver density (hepatic steatosis), 16% increase in skeletal muscle area, and 21% decrease in skeletal muscle density (myosteatosis) (all p < 0.001). The multisystem changes of metabolic syndrome can be objectively and retrospectively measured using automated CT biomarkers, with implications for diabetes, metabolic syndrome, and GLP-1 agonists.

Asunto(s)

Biomarcadores , Composición Corporal , Hemoglobina Glucada , Síndrome Metabólico , Tomografía Computarizada por Rayos X , Humanos , Síndrome Metabólico/metabolismo , Síndrome Metabólico/diagnóstico por imagen , Femenino , Hemoglobina Glucada/metabolismo , Hemoglobina Glucada/análisis , Tomografía Computarizada por Rayos X/métodos , Masculino , Biomarcadores/sangre , Persona de Mediana Edad , Anciano , Diabetes Mellitus/metabolismo , Diabetes Mellitus/diagnóstico por imagen , Adulto , Estudios Retrospectivos , Grasa Intraabdominal/diagnóstico por imagen , Grasa Intraabdominal/metabolismo

RESUMEN

The cell interior is packed with macromolecules of mesoscale size, and this crowded milieu significantly influences cellular physiology. Cellular stress responses almost universally lead to inhibition of translation, resulting in polysome collapse and release of mRNA. The released mRNA molecules condense with RNA-binding proteins to form ribonucleoprotein (RNP) condensates known as processing bodies and stress granules. Here, we show that polysome collapse and condensation of RNA transiently fluidize the cytoplasm, and coarse-grained molecular dynamic simulations support this as a minimal mechanism for the observed biophysical changes. Increased mesoscale diffusivity correlates with the efficient formation of quality control bodies (Q-bodies), membraneless organelles that compartmentalize misfolded peptides during stress. Synthetic, light-induced RNA condensation also fluidizes the cytoplasm. Together, our study reveals a functional role for stress-induced translation inhibition and formation of RNP condensates in modulating the physical properties of the cytoplasm to enable efficient response of cells to stress conditions.

Asunto(s)

Citoplasma , Polirribosomas , Ribonucleoproteínas , Polirribosomas/metabolismo , Citoplasma/metabolismo , Humanos , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/genética , Simulación de Dinámica Molecular , ARN Mensajero/metabolismo , ARN Mensajero/genética , Biosíntesis de Proteínas , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/genética , Condensados Biomoleculares/metabolismo , Gránulos de Estrés/metabolismo , Gránulos de Estrés/genética

RESUMEN

STUDY DESIGN: Longitudinal cross-sectional. OBJECTIVES: To examine motives to, and perceived gains from, leisure-time physical activity (LTPA) in people with spinal cord injury (SCI). SETTING: Community. METHODS: One hundred and five physically active individuals with SCI undertook an online survey and a semi-structured interview. The Exercise Motives and Gains Inventory was used to examine the movies towards, and the gains from LTPA, and the Leisure-time Physical Activity Questionnaire was administered via interview to gather LTPA data. A cross-sectional analysis, which included descriptive, inferential, and regression statistics, was conducted on all participants, physical activity (PA) guideline adherers and PA guideline non-adherers. RESULTS: The most common motives for LTPA were improvements in health and fitness, management of appearance and weight, and avoidance of illness. The most common gains from LTPA included improved health, fitness, strength and endurance, increased nimbleness, and enjoyment and revitalisation. CONCLUSIONS: Whilst health enhancement appears to be a significant motivator for LTPA, other psychosocial aspects, such as affiliation and revitalisation, appear to influence engagement and volume of LTPA. Regular LTPA should be encouraged for its health benefits, and emphasis should be placed on promoting its ability to reduce illness, facilitate affiliation, and manage stress.

Asunto(s)

Ejercicio Físico , Actividades Recreativas , Motivación , Traumatismos de la Médula Espinal , Humanos , Traumatismos de la Médula Espinal/rehabilitación , Traumatismos de la Médula Espinal/psicología , Masculino , Femenino , Motivación/fisiología , Persona de Mediana Edad , Adulto , Ejercicio Físico/psicología , Estudios Transversales , Encuestas y Cuestionarios , Estudios Longitudinales , Adulto Joven , Anciano

RESUMEN

Our ability to calculate rate constants of biochemical processes using molecular dynamics simulations is severely limited by the fact that the time scales for reactions, or changes in conformational state, scale exponentially with the relevant free-energy barrier heights. In this work, we improve upon a recently proposed rate estimator that allows us to predict transition times with molecular dynamics simulations biased to rapidly explore one or several collective variables (CVs). This approach relies on the idea that not all bias goes into promoting transitions, and along with the rate, it estimates a concomitant scale factor for the bias termed the "CV biasing efficiency" γ. First, we demonstrate mathematically that our new formulation allows us to derive the commonly used Infrequent Metadynamics (iMetaD) estimator when using a perfect CV, where γ = 1. After testing it on a model potential, we then study the unfolding behavior of a previously well characterized coarse-grained protein, which is sufficiently complex that we can choose many different CVs to bias, but which is sufficiently simple that we are able to compute the unbiased rate directly. For this system, we demonstrate that predictions from our new Exponential Average Time-Dependent Rate (EATR) estimator converge to the true rate constant more rapidly as a function of bias deposition time than does the previous iMetaD approach, even for bias deposition times that are short. We also show that the γ parameter can serve as a good metric for assessing the quality of the biasing coordinate. We demonstrate that these results hold when applying the methods to an atomistic protein folding example. Finally, we demonstrate that our approach works when combining multiple less-than-optimal bias coordinates, and adapt our method to the related "OPES flooding" approach. Overall, our time-dependent rate approach offers a powerful framework for predicting rate constants from biased simulations.

RESUMEN

Objectives: Adults with spinal cord injury (SCI) are often sedentary, increasing their risk of cardiometabolic diseases. Leisure-time Physical Activity (LTPA) is physical activity completed during recreation time for enjoyment. We aimed to quantify LTPA in people ≥45 years with SCI and to explore its relationship with participants' characteristics. Methods: This is a secondary analysis on a subset of the Australian International SCI Survey in participants ≥45 years, at least 12 months post-injury. We described levels of LTPA and used multivariable regressions to estimate the associations between participant characteristics and LTPA. Results: Of 1,281 participants (mean age: 62.7 years, mean time since injury: 18.7 years; 74% males) 44% reported no participation in LTPA. The average LTPA participation was 197 (SD 352) minutes per week (median: 50). Females (ß = -62.3, 95% CI [-112.9, -11.7]), and participants with non-traumatic injuries (ß = -105.2, 95% CI [-165.9, -44.6]) performed less LTPA. Time since injury was not associated with moderate-to-heavy LTPA (LR: Probability > F = 0.785). Conclusion: LTPA promotion in the SCI population ≥45 years focusing on females and non-traumatic injuries is warranted.

Asunto(s)

Ejercicio Físico , Actividades Recreativas , Traumatismos de la Médula Espinal , Humanos , Traumatismos de la Médula Espinal/epidemiología , Femenino , Masculino , Persona de Mediana Edad , Australia , Anciano , Encuestas y Cuestionarios

RESUMEN

Climate change is an existential threat to the environmental and socioeconomic sustainability of the coastal zone and impacts will be complex and widespread. Evidence from California and across the United States shows that climate change is impacting coastal communities and challenging managers with a plethora of stressors already present. Widespread action could be taken that would sustain California's coastal ecosystems and communities. In this perspective, we highlight the main threat to coastal sustainability: the compound effects of episodic events amplified with ongoing climate change, which will present unprecedented challenges to the state. We present two key challenges for California's sustainability in the coastal zone: 1) accelerating sea-level rise combined with storm impacts, and 2) continued warming of the oceans and marine heatwaves. Cascading effects from these types of compounding events will occur within the context of an already stressed system that has experienced extensive alterations due to intensive development, resource extraction and harvesting, spatial containment, and other human use pressures. There are critical components that could be used to address these immediate concerns, including comanagement strategies that include diverse groups and organizations, strategic planning integrated across large areas, rapid implementation of solutions, and a cohesive and policy relevant research agenda for the California coast. Much of this has been started in the state, but the scale could be increased, and timelines accelerated. The ideas and information presented here are intended to help expand discussions to sharpen the focus on how to encourage sustainability of California's iconic coastal region.

RESUMEN

Objectives: To investigate the amount of Leisure-Time Physical Activity (LTPA) that people over 45 years with a spinal cord injury (SCI) performed and to determine the frequency, duration, intensity, and modality of LTPA performed. Data Sources: We searched 5 major electronic databases (CINAHL, SCOPUS, EMBASE, MEDLINE, and PubMed) from inception to March 2023. Study Selection: Cross-sectional, longitudinal studies and control arm of controlled trials that assessed LTPA in participants over 45 years old, with a SCI. We included 19 studies in the review and 11 in the meta-analysis. Data Extraction: We followed the PRISMA checklist for Systematic Reviews. Two review authors independently assessed the risk of bias and extracted data on participants' demographics, injury characteristics, and LTPA participation of the included studies. Risk of bias was assessed using the Joanne Briggs Institute critical appraisal tool for cross-sectional studies. Any conflicts were resolved by a third author. Data Synthesis: We found considerable variability in LTPA participation in adults 45 years and older with SCI. An estimated 27%-64% of participants did not take part in any LTPA. A random effects meta-analysis model was completed for studies that reported total or moderate-to-heavy LTPA scores in minutes per week. Overall, participants (n=1675) engaged in 260 [205;329] (mean [95% CI]) mins/week of total LTPA. Those participating in moderate-heavy intensity LTPA (n=364) completed 173 [118; 255] (mean [95% CI]) mins/week. LTPA modalities included walking, wheeling, hand-cycling, basketball, and swimming, among others. Conclusions: While many older adults with SCI seem to be meeting the recommended weekly physical activity volume, many still remain sedentary. There was significant variation in reporting of frequency, intensity, and duration of LTPA and reporting on modality was limited. Because of differences in reporting, it was challenging to compare results across studies. Data constraints prevented subgroup analysis of LTPA disparities between paraplegia and tetraplegia.

RESUMEN

AIM AND RATIONALE: Problems with manual dexterity and cognition impact the everyday performance of people with multiple sclerosis (PwMS). Accumulated findings point to the relationship between deficits in manual dexterity and auditory domains of cognition with a lack of evidence on visuospatial and verbal aspects of cognitive functioning. Therefore, this study explores the relationship between manual dexterity and cognition in a cohort of PwMS. METHOD: This cross-sectional study collected data from 63 PwMS aged 22 to 55 through a convenient sampling method. Participants were diagnosed with relapsing-remitting multiple sclerosis (RRMS). Cognition was measured using a multi-domain computerized cognitive testing, NeuroTrax, and manual dexterity was measured using a 9-hole peg assessment. Spearman correlation was used to identify the correlation among cognition subtests as well as with manual dexterity. Linear regression analysis was also conducted to identify whether manual dexterity predicts cognitive functioning. RESULTS: A significant negative correlation was found between 9-hole peg scores and global cognitive scores (GCS), r = -0.34, p = 006. The manual dexterity scores were also shown to predict GCS, R2= 0.165, p = 0.001. CONCLUSION: Manual dexterity was found to not only predict cognitive dysfunction but was also associated with multiple cognitive domains. Understanding the relationship between manual dexterity and cognition and the inferred progression of deficits can assist clinicians to provide interventions at earlier stages of disease progression to potentially increase daily functioning and quality of life (QoL).

Asunto(s)

Esclerosis Múltiple Recurrente-Remitente , Humanos , Masculino , Femenino , Adulto , Estudios Transversales , Persona de Mediana Edad , Adulto Joven , Esclerosis Múltiple Recurrente-Remitente/fisiopatología , Esclerosis Múltiple Recurrente-Remitente/complicaciones , Pruebas Neuropsicológicas , Disfunción Cognitiva/etiología , Disfunción Cognitiva/fisiopatología , Cognición/fisiología , Destreza Motora/fisiología , Esclerosis Múltiple/complicaciones , Esclerosis Múltiple/fisiopatología

RESUMEN

BACKGROUND: South, East, and Southeast Asia are among the regions of the world with the highest estimated prevalence of inadequate zinc intake. Because populations in those regions eat rice as their main staple, zinc biofortification of rice can potentially improve zinc intake, especially among the most vulnerable. OBJECTIVES: We modeled the impact of the consumption of zinc-biofortified rice on zinc intake and inadequacy among women of childbearing age and young children nationally in Indonesia, the Philippines, and at a subnational level in Bangladesh. METHODS: We conducted an ex-ante analysis by applying increments of zinc content in rice, from a baseline level of 16 parts per million (ppm) to 100 ppm, and based on rice consumption data to substitute levels of conventional rice with zinc-biofortified rice varying between 10% and 70%. RESULTS: Among all datasets evaluated from these 3 countries, the prevalence of dietary zinc inadequacy at baseline was 94%-99% among women of childbearing age, 77%-100% among children 4-5 y old, and 27%-78% among children 1-3 y old. At the current breeding target of 28 ppm, zinc-biofortified rice has the potential to decrease zinc inadequacy by ≤50% among women and children in rural Bangladesh and among children in the Philippines where consumption of rice is higher compared with Indonesia. CONCLUSIONS: Our analysis shows that increasing zinc content in rice ≤45 ppm reduces the burden of zinc inadequacy substantially, after which we encourage programs to increase coverage to reach the highest number of beneficiaries.

Asunto(s)

Alimentos Fortificados , Oryza , Zinc , Oryza/química , Humanos , Filipinas , Bangladesh , Zinc/análisis , Indonesia , Femenino , Preescolar , Lactante , Adulto , Dieta , Masculino , Adulto Joven , Biofortificación , Adolescente , Prevalencia

RESUMEN

Structures of molecular crystals are identified using scattering techniques because we cannot see inside them. Micrometre-sized colloidal particles enable the real-time observation of crystallization with optical microscopy, but in practice this is still hampered by a lack of 'X-ray vision'. Here we introduce a system of index-matched fluorescently labelled colloidal particles and demonstrate the robust formation of ionic crystals in aqueous solution, with structures that can be controlled by size ratio and salt concentration. Full three-dimensional coordinates of particles are distinguished through in situ confocal microscopy, and the crystal structures are identified via comparison of their simulated scattering pattern with known atomic arrangements. Finally, we leverage our ability to look inside colloidal crystals to observe the motion of defects and crystal melting in time and space and to reveal the origin of crystal twinning. Using this platform, the path to real-time analysis of ionic colloidal crystallization is now 'crystal clear'.

RESUMEN

OBJECTIVE: To assess the diagnostic performance of post-contrast CT for predicting moderate hepatic steatosis in an older adult cohort undergoing a uniform CT protocol, utilizing hepatic and splenic attenuation values. MATERIALS AND METHODS: A total of 1676 adults (mean age, 68.4 ± 10.2 years; 1045M/631F) underwent a CT urothelial protocol that included unenhanced, portal venous, and 10-min delayed phases through the liver and spleen. Automated hepatosplenic segmentation for attenuation values (in HU) was performed using a validated deep-learning tool. Unenhanced liver attenuation < 40.0 HU, corresponding to > 15% MRI-based proton density fat, served as the reference standard for moderate steatosis. RESULTS: The prevalence of moderate or severe steatosis was 12.9% (216/1676). The diagnostic performance of portal venous liver HU in predicting moderate hepatic steatosis (AUROC = 0.943) was significantly better than the liver-spleen HU difference (AUROC = 0.814) (p < 0.001). Portal venous phase liver thresholds of 80 and 90 HU had a sensitivity/specificity for moderate steatosis of 85.6%/89.6%, and 94.9%/74.7%, respectively, whereas a liver-spleen difference of -40 HU and -10 HU had a sensitivity/specificity of 43.5%/90.0% and 92.1%/52.5%, respectively. Furthermore, livers with moderate-severe steatosis demonstrated significantly less post-contrast enhancement (mean, 35.7 HU vs 47.3 HU; p < 0.001). CONCLUSION: Moderate steatosis can be reliably diagnosed on standard portal venous phase CT using liver attenuation values alone. Consideration of splenic attenuation appears to add little value. Moderate steatosis not only has intrinsically lower pre-contrast liver attenuation values (< 40 HU), but also enhances less, typically resulting in post-contrast liver attenuation values of 80 HU or less. CLINICAL RELEVANCE STATEMENT: Moderate steatosis can be reliably diagnosed on post-contrast CT using liver attenuation values alone. Livers with at least moderate steatosis enhance less than those with mild or no steatosis, which combines with the lower intrinsic attenuation to improve detection. KEY POINTS: The liver-spleen attenuation difference is frequently utilized in routine practice but appears to have performance limitations. The liver-spleen attenuation difference is less effective than liver attenuation for moderate steatosis. Moderate and severe steatosis can be identified on standard portal venous phase CT using liver attenuation alone.

RESUMEN

BACKGROUND: Functional electrical stimulation (FES) cycling has been reported to enhance muscle strength and improve muscle fatigue resistance after spinal cord injury (SCI). Despite its proposed benefits, the quantification of muscle fatigue during FES cycling remains poorly documented. This study sought to quantify the relationship between the vibrational performance of electrically-evoked muscles measured through mechanomyography (MMG) and its oxidative metabolism through near-infrared spectroscopy (NIRS) characteristics during FES cycling in fatiguing paralyzed muscles in individuals with SCI. METHODS: Six individuals with SCI participated in the study. They performed 30 min of FES cycling with MMG and NIRS sensors on their quadriceps throughout the cycling, and the signals were analyzed. RESULTS: A moderate negative correlation was found between MMG root mean square (RMS) and oxyhaemoglobin (O2Hb) [r = -0.38, p = 0.003], and between MMG RMS and total hemoglobin (tHb) saturation [r = -0.31, p = 0.017]. Statistically significant differences in MMG RMS, O2Hb, and tHb saturation occurred during pre- and post-fatigue of FES cycling (p < 0.05). CONCLUSIONS: MMG RMS was negatively associated with O2Hb and muscle oxygen derived from NIRS. MMG and NIRS sensors showed good inter-correlations, suggesting a promising use of MMG for characterizing metabolic fatigue at the muscle oxygenation level during FES cycling in individuals with SCI.

RESUMEN

BACKGROUND: Gait variability is a common feature in neurodegenerative diseases and has been linked to cognitive impairment. Despite this link, the influence of specific cognitive domains, such as memory, visual spatial skills, executive function, and verbal function on gait variability is not well-understood. OBJECTIVE: To investigate the predictive value of these specific cognitive domains on gait variability in people with mild cognitive impairment (MCI) and dementia during preferred and dual task walking. METHOD: One hundred and two participants with either MCI or dementia underwent a comprehensive cognitive assessment and completed preferred and dual-task walking trials on a pressure-sensing walkway. Gait variability was assessed using the PKMAS software. Lower extremity function was evaluated with a self-reported validated scale. RESULTS: Our findings indicate that only visual spatial abilities had a moderate predictive value on gait variability [F (1, 78) = 17.30, p < 0.01, r = 0.43], both in preferred pace walking (70% direct effect) and dual-task walking (90% direct effect) (p's < 0.05). Additionally, lower extremity functional skills had a significant indirect effect (30%) on gait variability in preferred walking contexts. CONCLUSION: For individuals diagnosed with MCI or dementia, increased gait variability may be driven by deficits in visual spatial processing. An increased understanding of the role of visual spatial processing in gait variability can aid in the assessment and management of individuals with MCI or dementia, potentially leading to targeted interventions to improve mobility and safety.

Asunto(s)

Disfunción Cognitiva , Demencia , Humanos , Disfunción Cognitiva/fisiopatología , Masculino , Femenino , Anciano , Demencia/fisiopatología , Anciano de 80 o más Años , Marcha/fisiología , Función Ejecutiva/fisiología , Desempeño Psicomotor/fisiología , Trastornos Neurológicos de la Marcha/fisiopatología , Trastornos Neurológicos de la Marcha/etiología , Caminata/fisiología

RESUMEN

OBJECTIVE: We analyzed quantitative computed tomography (CT) and chemical shift-encoded magnetic resonance imaging (MRI) data from a Chinese cohort to investigate the effects of BMI and aging on different adipose tissue (AT) depots. METHODS: In 400 healthy, community-dwelling individuals aged 22 to 83 years, we used MRI to quantify proton density fat fraction (PDFF) of the lumbar spine (L2-L4) bone marrow AT (BMAT), the psoas major and erector spinae (ES) muscles, and the liver. Abdominal total AT, visceral AT (VAT), and subcutaneous AT (SAT) areas were measured at the L2-L3 level using quantitative CT. Partial correlation analysis was used to evaluate the relationship of each AT variable with age and BMI. Multiple linear regression analysis was performed in which each AT variable was evaluated in turn as a function of age and the other five independent AT measurements. RESULTS: Of the 168 men, 29% had normal BMI (<24.0 kg/m2), 47% had overweight (24.0-27.9 kg/m2), and 24% had obesity (≥ 28.0 kg/m2). In the 232 women, the percentages were 46%, 32%, and 22%, respectively. Strong or very strong correlations with BMI were found for total AT, VAT, and SAT in both sexes. BMAT and ES PDFF was strongly correlated with age in women and moderately correlated in men. In both sexes, BMAT PDFF correlated only with age and not with any of the other AT depots. Psoas PDFF correlated only with ES PDFF and not with age or the other AT depots. Liver PDFF correlated with BMI and VAT and weakly with SAT in men. VAT and SAT correlated with age and each other in both sexes. CONCLUSIONS: Age and BMI are both associated with adiposity, but their effects differ depending on the type of AT.

Asunto(s)

Adiposidad , Índice de Masa Corporal , Médula Ósea , Grasa Intraabdominal , Hígado , Imagen por Resonancia Magnética , Tomografía Computarizada por Rayos X , Humanos , Masculino , Persona de Mediana Edad , Femenino , Adulto , Anciano , Imagen por Resonancia Magnética/métodos , Tomografía Computarizada por Rayos X/métodos , Grasa Intraabdominal/diagnóstico por imagen , Hígado/diagnóstico por imagen , Anciano de 80 o más Años , Médula Ósea/diagnóstico por imagen , Adulto Joven , Obesidad/diagnóstico por imagen , Grasa Subcutánea/diagnóstico por imagen , Envejecimiento/fisiología , Músculo Esquelético/diagnóstico por imagen , Sobrepeso/diagnóstico por imagen , Vértebras Lumbares/diagnóstico por imagen , China , Factores de Edad

RESUMEN

OBJECTIVE: To determine which bones and which grades had the highest inter-rater variability when employing the Tanner-Whitehouse (T-W) method. MATERIALS AND METHODS: Twenty-four radiologists were recruited and trained in the T-W classification of skeletal development. The consistency and skill of the radiologists in determining bone development status were assessed using 20 pediatric hand radiographs of children aged 1 to 18 years old. Four radiologists had a poor concordance rate and were excluded. The remaining 20 radiologists undertook a repeat reading of the radiographs, and their results were analyzed by comparing them with the mean assessment of two senior experts as the reference standard. Concordance rate, scoring, and Kendall's W were calculated to evaluate accuracy and consistency. RESULTS: Both the radius, ulna, and short finger (RUS) system (Kendall's W = 0.833) and the carpal (C) system (Kendall's W = 0.944) had excellent consistency, with the RUS system outperforming the C system in terms of scores. The repeatability analysis showed that the second rating test, performed after 2 months of further bone age assessment (BAA) practice, was more consistent and accurate than the first. The capitate had the lowest average concordance rate and scoring, as well as the lowest overall concordance rate for its D classification. Moreover, the G classifications of the seven carpal bones all had a concordance rate less than 0.6. The bones with lower Kendall's W were likewise those with lower scores and concordance rates. CONCLUSION: The D grade of the capitate showed the highest variation, and the use of the Tanner-Whitehouse 3rd edition (T-W3) to determine bone age (BA) was frequently inconsistent. A more comprehensive description with a focus on inaccuracy bones or ratings and a modification to the T-W3 approach would significantly advance BAA.

RESUMEN

Micro- and nanoplastics (MNPs) have become ubiquitous contaminants of water and foods, resulting in high levels of human ingestion exposure. MNPs have been found in human blood and multiple tissues, suggesting that they are readily absorbed by the gastrointestinal tract (GIT) and widely distributed. Growing toxicological evidence suggests that ingested MNPs may pose a serious health threat. The potential genotoxicity of MNPs, however, remains largely unknown. In this study, genotoxicity of primary and environmentally relevant secondary MNPs was assessed in a triculture small intestinal epithelium (SIE) model using the CometChip assay. Aqueous suspensions of 25 and 1000 nm carboxylated polystyrene spheres (PS25C and PS1KC), and incinerated polyethylene (PEI PM0.1) were subjected to simulated GIT digestion to create physiologically relevant exposures (digestas), which were applied to the SIE model at final MNP concentrations of 1, 5, and 20 µg/mL for 24 or 48 h. PS25C and PS1KC induced DNA damage in a time- and concentration-dependent manner. To our knowledge, this is one of the first assessment of MNP genotoxicity in an integrated in vitro ingestion platform including simulated GIT digestion and a triculture SIE model. These findings suggest that ingestion of high concentrations of carboxylated PS MNPs could have serious genotoxic consequences in the SIE.

RESUMEN

Background: People with spinal cord injuries (SCIs) often have trouble remaining active because of paralysis. In the past, exercise recommendations focused on the non-paralyzed muscles in the arms, which provides limited benefits. However, recent studies show that electrical stimulation can help engage the paralyzed extremities, expanding the available muscle mass for exercise. Methods: The authors provide an evidence-based approach using expertise from diverse fields, supplemented by evidence from key studies toward the management of electrical stimulation therapies in individuals with SCIs. Literature searches were performed separately using the PubMed, Medline, and Google Scholar search engines. The keywords used for the searches included functional electrical stimulation cycling, hybrid cycling, neuromuscular electrical stimulation exercise, spinal cord injury, cardiovascular health, metabolic health, muscle strength, muscle mass, bone mass, upper limb treatment, diagnostic and prognostic use of functional electrical stimulation, tetraplegic hands, and hand deformities after SCI. The authors recently presented this information in a workshop at a major rehabilitation conference. Additional information beyond what was presented at the workshop was added for the writing of this paper. Results: Functional electrical stimulation (FES) cycling can improve aerobic fitness and reduce the risk of cardiovascular and metabolic diseases. The evidence indicates that while both FES leg cycling and neuromuscular electrical stimulation (NMES) resistance training can increase muscle strength and mass, NMES resistance training has been shown to be more effective for producing muscle hypertrophy in individual muscle groups. The response to the electrical stimulation of muscles can also help in the diagnosis and prognosis of hand dysfunction after tetraplegia. Conclusions: Electrical stimulation activities are safe and effective methods for exercise and testing for motor neuron lesions in individuals with SCIs and other paralytic or paretic conditions. They should be considered part of a comprehensive rehabilitation program in diagnosing, prognosing, and treating individuals with SCIs to improve function, physical activity, and overall health.