Unfolding cross-linkers as rheology regulators in F-actin networks

We report on the nonlinear mechanical properties of a statistically homogeneous, isotropic semiflexible network cross-linked by polymers containing numerous small unfolding domains, such as the ubiquitous F-actin cross-linker Filamin. We show that the inclusion of such proteins has a dramatic effect on the large strain behavior of the network. Beyond a strain threshold, which depends on network density, the unfolding of protein domains leads to bulk shear softening. Past this critical strain, the network spontaneously organizes itself so that an appreciable fraction of the Filamin cross-linkers are at the threshold of domain unfolding. We discuss via a simple mean-field model the cause of this network organization and suggest that it may be the source of power-law relaxation observed in in vitro and in intracellular microrheology experiments. We present data which fully justifies our model for a simplified network architecture.Comment: 11 pages, 4 figures. to appear in Physical Review

Using a discrete choice experiment involving cost to value a classification system measuring the quality of life impact of self-management for diabetes

Objective: This paper describes the use of a novel approach in health valuation of a discrete choice experiment (DCE) including a cost attribute to value a recently developed classification system for measuring the quality of life impact (both health and treatment experience) of self-management for diabetes. Methods: A large online survey was conducted using DCE with cost on UK respondents from the general population (n=1,497) and individuals with diabetes (n=405). The data was modelled using a conditional logit model with robust standard errors. The marginal rate of substitution (MRS) was used to generate willingness to pay estimates for every state defined by the classification system. Robustness of results was assessed by including interaction effects for household income. Results: There were some logical inconsistencies and insignificant coefficients for the milder levels of some attributes. There were some differences in the rank ordering of different attributes for the general population and diabetes patients. The willingness to pay to avoid the most severe state was £1,118.53 per month for the general population and £2,356.02 per month for the diabetes patient population. The results were largely robust. Conclusion: Health and self-management can be valued in a single classification system using DCE with cost. The MRS for key attributes can be used to inform cost-benefit analysis of self-management interventions in diabetes using results from clinical studies where this new classification system has been applied. The method shows promise, but found large willingness to pay estimates exceeding the cost levels used in the survey

Blood pressure and cholesterol level checks as dynamic interrelated screening examinations

This study analysed the determinants of screening uptake for blood pressure and cholesterol level checks. Furthermore, it investigated the presence of possible spillover effects from one type of cardiovascular screening to another type of cardiovascular screening. A dynamic random effects bivariate panel probit model with initial conditions (Wooldridge-type estimator) was adopted for the estimation. The outcome variables were the participation in blood pressure and cholesterol level checks by individuals in a given year. The balanced panel sample of 21,138 observations was constructed from 1,626 individuals from the British Household Panel Survey (BHPS) between 1996 and 2008. The analysis showed the significance of past screening behaviour for both cardiovascular screening examinations. For both cardiovascular screening examinations state dependence exist. The study also shows a significant spillover effect of the cholesterol level check on the blood pressure check and vice versa. Also a poorer health status led to a higher uptake for both types of screening examinations. Changes in recommendations have to consider the fact that taking part in one type of cardiovascular screening examination can influence the decision to take part in the other type of cardiovascular screening examination

Who uses NHS health checks? Investigating the impact of ethnicity and gender and method of invitation on uptake of NHS health checks

Background NHS Health Checks is a national risk assessment prevention programme for all individuals aged 40-74 that reside in England. Through the systematic assessment of an individual’s ten year disease risk, this programme aims to provide early identification and subsequent management of this risk. However, there is limited evidence on how socio-demographic factors impact on uptake and what influence the invitation method has on uptake to this programme. Methods NHS Health Check data from April 2013 to March 2014 was analysed (N = 50,485) for all 30 GP Practices in Luton, a culturally diverse town in England, UK. Data was collected for age, ethnicity, uptake (attendance and non attendance) and invitation method (letter written, verbal face-to-face, telephone). Actual usage of NHS Health Checks was determined for each ethnic group of the population and compared using Chi-square analysis. Results The overall uptake rate for Luton was 44 %, markedly lower that the set target of 50–75 %. The findings revealed a variation of uptake in relation to age, gender, level of deprivation. Ethnicity and gender variations were also found, with ‘White British’ ‘Black Caribbean’ and ‘Indian’ patients most likely to take up a NHS Health Check. However, patients from ‘Any Other White Background’ and ‘Black African’ were significantly less likely to uptake an NHS Health Check compared to all other ethnic groups. Ethnicity and gender differences were also noted in relation to invitation method. Conclusions The findings revealed that different invitation methods were effective for different ethnic and gender groups. Therefore, it is suggested that established protocols of invitation are specifically designed for maximizing the response rate for each population group. Future research should now focus on uncovering the barriers to uptake in particular culturally diverse population groups to determine how public health teams can better engage with these communities

Developing preference-based measures for diabetes: DHP-3D and DHP-5D

© 2017 Diabetes UK Aims: The aim of this study was to develop two diabetes-specific preference-based measures [the Diabetes Health Profile–3 Dimension (DHP-3D) and the Diabetes Health Profile–5 Dimension (DHP-5D)] for use in the calculation of Quality Adjusted Life Years, a key outcome in economic evaluation. These measures were based on the non-preference-based instrument the Diabetes Health Profile. Methods: For DHP-3D, psychometric and Rasch analyses were used to develop a health state classification system based on the Diabetes Health Profile–18 (DHP-18). The DHP-5D added two dimensions to the DHP-3D to extend the range of impacts measured. Each classification system was valued by 150 general public respondents in the United Kingdom using Time Trade Off (TTO). Multivariate regression was used to estimate utility value sets. The matched dimensions across each measure were compared using z-score tests. Results: The DHP-3D included three dimensions defined as mood, eating and social limitations, and the DHP-5D added dimensions defined as hypoglycaemic attacks and vitality. For both, the random effects generalized least squares regression model produced consistent value sets, with the DHP-3D and DHP-5D ranging from 0.983 (best state) to 0.717 (worst state), and 0.979 to 0.618 respectively. The addition of the two extra dimensions leads to significant differences for the more severe levels of each matched dimension. Conclusions: We have developed two diabetes-specific preference-based measures that, subject to psychometric assessment, can be used to provide condition-specific utility values to complement generic utilities from more widely validated measures such as the EuroQol-5 Dimension

Regulation of Glucose Metabolism by MuRF1 and Treatment of Myopathy in Diabetic Mice with Small Molecules Targeting MuRF1

The muscle-specific ubiquitin ligase MuRF1 regulates muscle catabolism during chronic wasting states, although its roles in general metabolism are less-studied. Here, we metabolically profiled MuRF1-deficient knockout mice. We also included knockout mice for MuRF2 as its closely related gene homolog. MuRF1 and MuRF2-KO (knockout) mice have elevated serum glucose, elevated triglycerides, and reduced glucose tolerance. In addition, MuRF2-KO mice have a reduced tolerance to a fat-rich diet. Western blot and enzymatic studies on MuRF1-KO skeletal muscle showed perturbed FoxO-Akt signaling, elevated Akt-Ser-473 activation, and downregulated oxidative mitochondrial metabolism, indicating potential mechanisms for MuRF1,2-dependent glucose and fat metabolism regulation. Consistent with this, the adenoviral re-expression of MuRF1 in KO mice normalized Akt-Ser-473, serum glucose, and triglycerides. Finally, we tested the MuRF1/2 inhibitors MyoMed-205 and MyoMed-946 in a mouse model for type 2 diabetes mellitus (T2DM). After 28 days of treatment, T2DM mice developed progressive muscle weakness detected by wire hang tests, but this was attenuated by the MyoMed-205 treatment. While MyoMed-205 and MyoMed-946 had no significant effects on serum glucose, they did normalize the lymphocyte–granulocyte counts in diabetic sera as indicators of the immune response. Thus, small molecules directed to MuRF1 may be useful in attenuating skeletal muscle strength loss in T2DM conditions

Small‐molecule‐mediated chemical knock‐down of MuRF1/MuRF2 and attenuation of diaphragm dysfunction in chronic heart failure

Background: Chronic heart failure (CHF) leads to diaphragm myopathy that significantly impairs quality of life and worsens prognosis. In this study, we aimed to assess the efficacy of a recently discovered small‐molecule inhibitor of MuRF1 in treating CHF‐induced diaphragm myopathy and loss of contractile function. Methods: Myocardial infarction was induced in mice by ligation of the left anterior descending coronary artery. Sham‐operated animals (sham) served as controls. One week post‐left anterior descending coronary artery ligation animals were randomized into two groups—one group was fed control rodent chow, whereas the other group was fed a diet containing 0.1% of the compound ID#704946—a recently described MuRF1‐interfering small molecule. Echocardiography confirmed development of CHF after 10 weeks. Functional and molecular analysis of the diaphragm was subsequently performed. Results: Chronic heart failure induced diaphragm fibre atrophy and contractile dysfunction by ~20%, as well as decreased activity of enzymes involved in mitochondrial energy production (P < 0.05). Treatment with compound ID#704946 in CHF mice had beneficial effects on the diaphragm: contractile function was protected, while mitochondrial enzyme activity and up‐regulation of the MuRF1 and MuRF2 was attenuated after infarct. Conclusions: Our murine CHF model presented with diaphragm fibre atrophy, impaired contractile function, and reduced mitochondrial enzyme activities. Compound ID#704946 rescued from this partially, possibly by targeting MuRF1/MuRF2. However, at this stage of our study, we refrain to claim specific mechanism(s) and targets of compound ID#704946, because the nature of changes after 12 weeks of feeding is likely to be complex and is not necessarily caused by direct mechanistic effects

Which Comprehensive Geriatric Assessment (CGA) instruments are currently used in Germany : a survey

Background: The Comprehensive Geriatric Assessment (CGA) records geriatric syndromes in a standardized manner, allowing individualized treatment tailored to the patient’s needs and resources. Its use has shown a beneficial effect on the functional outcome and survival of geriatric patients. A recently published German S1 guideline for level 2 CGA provides recommendations for the use of a broad variety of different assessment instruments for each geriatric syndrome. However, the actual use of assessment instruments in routine geriatric clinical practice and its consistency with the guideline and the current state of literature has not been investigated to date. Methods: An online survey was developed by an expert group of geriatricians and sent to all licenced geriatricians (n = 569) within Germany. The survey included the following geriatric syndromes: motor function and self-help capability, cognition, depression, pain, dysphagia and nutrition, social status and comorbidity, pressure ulcers, language and speech, delirium, and frailty. Respondents were asked to report which geriatric assessment instruments are used to assess the respective syndromes. Results: A total of 122 clinicians participated in the survey (response rate: 21%); after data cleaning, 76 data sets remained for analysis. All participants regularly used assessment instruments in the following categories: motor function, self-help capability, cognition, depression, and pain. The most frequently used instruments in these categories were the Timed Up and Go (TUG), the Barthel Index (BI), the Mini Mental State Examination (MMSE), the Geriatric Depression Scale (GDS), and the Visual Analogue Scale (VAS). Limited or heterogenous assessments are used in the following categories: delirium, frailty and social status. Conclusions: Our results show that the assessment of motor function, self-help capability, cognition, depression, pain, and dysphagia and nutrition is consistent with the recommendations of the S1 guideline for level 2 CGA. Instruments recommended for more frequent use include the Short Physical Performance Battery (SPPB), the Montreal Cognitive Assessment (MoCA), and the WHO-5 (depression). There is a particular need for standardized assessment of delirium, frailty and social status. The harmonization of assessment instruments throughout geriatric departments shall enable more effective treatment and prevention of age-related diseases and syndromes

ProRepeat: an integrated repository for studying amino acid tandem repeats in proteins

ProRepeat (http://prorepeat.bioinformatics.nl/) is an integrated curated repository and analysis platform for in-depth research on the biological characteristics of amino acid tandem repeats. ProRepeat collects repeats from all proteins included in the UniProt knowledgebase, together with 85 completely sequenced eukaryotic proteomes contained within the RefSeq collection. It contains non-redundant perfect tandem repeats, approximate tandem repeats and simple, low-complexity sequences, covering the majority of the amino acid tandem repeat patterns found in proteins. The ProRepeat web interface allows querying the repeat database using repeat characteristics like repeat unit and length, number of repetitions of the repeat unit and position of the repeat in the protein. Users can also search for repeats by the characteristics of repeat containing proteins, such as entry ID, protein description, sequence length, gene name and taxon. ProRepeat offers powerful analysis tools for finding biological interesting properties of repeats, such as the strong position bias of leucine repeats in the N-terminus of eukaryotic protein sequences, the differences of repeat abundance among proteomes, the functional classification of repeat containing proteins and GC content constrains of repeats’ corresponding codons

MyoMed205 Counteracts Titin Hyperphosphorylation and the Expression of Contraction-Regulating Proteins in a Rat Model of HFpEF

Background Heart failure with preserved ejection fraction (HFpEF) is associated with exercise intolerance, accompanied by alterations in the peripheral skeletal muscle (SKM). We have recently shown that titin, a giant sarcomere protein, is hyperphosphorylated in HFpEF. MuRF1 is a muscle-specific ubiquitin E3-ligase that interacts with titin. Blocking this interaction via small molecules (MyoMed205) can improve muscle function and mitochondrial activity in HFpEF. This study aimed to investigate the impact of MyoMed205 on titin phosphorylation and its association with changes in muscle structure and function. Methods Obese ZSF1 rats with established HFpEF received rat chow with (n = 15) or without (n = 15) MyoMed205 and were compared with lean littermates (n = 15), serving as controls. After 12 weeks, in vitro SKM force, atrophy and titin—as well as contractile protein expression—were evaluated (soleus and extensor digitorum longus [EDL]). Statistical analysis was performed via multiple unpaired t-test or one-way ANOVA. Results In HFpEF, titin hyperphosphorylation by 13% in the EDL (p = 0.09) and 14% (p = 0.03) in the soleus muscle was evident. This hyperphosphorylation was driven in part by an increase in S11878 phosphorylation (EDL: +68%, p = 0.004; Sol: +23.8%, p = 0.03), which was linked to myofiber atrophy (r = −0.68, p = 0.006) and a decline in maximal specific muscle force (r = −0.54, p = 0.008). In the EDL, significant changes in protein expression related to atrophy (MuRF1 [+24.9%, p = 0.02], GDF8 [+20.6%, p = 0.09]) and calcium handling (slow troponin C [−46%, p = 0.02], fast troponin I [+35.8%, p = 0.02]) were found in HFpEF. All of the above-mentioned effects in HFpEF were almost completely abolished by MyoMed205 treatment, and significantly elevated titin expression was visible (+19.7%, pcon = 0.04, pHFpEF = 0.01). Conclusions Titin hyperphosphorylation may negatively impact skeletal muscle integrity and function in HFpEF. MyoMed205 reduced titin hyperphosphorylation and was associated with preserved skeletal muscle function and mass. Further studies are necessary to confirm the direct role of titin hyperphosphorylation on muscle function and to evaluate the therapeutic potential of MyoMed205 in HFpEF