HSPB1, HSPB6, HSPB7 and HSPB8 Protect against RhoA GTPase-Induced Remodeling in Tachypaced Atrial Myocytes

BACKGROUND: We previously demonstrated the small heat shock protein, HSPB1, to prevent tachycardia remodeling in in vitro and in vivo models for Atrial Fibrillation (AF). To gain insight into its mechanism of action, we examined the protective effect of all 10 members of the HSPB family on tachycardia remodeling. Furthermore, modulating effects of HSPB on RhoA GTPase activity and F-actin stress fiber formation were examined, as this pathway was found of prime importance in tachycardia remodeling events and the initiation of AF. METHODS AND RESULTS: Tachypacing (4 Hz) of HL-1 atrial myocytes significantly and progressively reduced the amplitude of Ca²⁺ transients (CaT). In addition to HSPB1, also overexpression of HSPB6, HSPB7 and HSPB8 protected against tachypacing-induced CaT reduction. The protective effect was independent of HSPB1. Moreover, tachypacing induced RhoA GTPase activity and caused F-actin stress fiber formation. The ROCK inhibitor Y27632 significantly prevented tachypacing-induced F-actin formation and CaT reductions, showing that RhoA activation is required for remodeling. Although all protective HSPB members prevented the formation of F-actin stress fibers, their mode of action differs. Whilst HSPB1, HSPB6 and HSPB7 acted via direct prevention of F-actin formation, HSPB8-protection was mediated via inhibition of RhoA GTPase activity. CONCLUSION: Overexpression of HSPB1, as well as HSPB6, HSPB7 and HSPB8 independently protect against tachycardia remodeling by attenuation of the RhoA GTPase pathway at different levels. The cardioprotective role for multiple HSPB members indicate a possible therapeutic benefit of compounds able to boost the expression of single or multiple members of the HSPB family

Factors influencing the surgical process during shoulder joint replacement:Time-action analysis of five different prostheses and three different approaches

Background: To evaluate the per-operative process of shoulder joint replacement, time-action analysis can be used.Material/Methods: Forty procedures performed by 7 surgeons with different experience rising 5 different prostheses and 3 different Surgical approaches were analyzed.Results: The surgical procedures showed a large variation in, for example, duration, tasks of team members, and protocol used. The surgical procedure was influenced by several factors, such as the prosthesis used, the surgical approach, the patient's condition, and the experience of the surgeon. Exposure of the glenoid was difficult and several retractors were needed, which were held by an extra assistant or clamped to the table or the surgeon. Two main limitations were seen in all procedures: repeated actions and waiting. Also, five errors could be identified. None of the alignment instruments was completely reliable and they allowed the surgeon to make major errors.Conclusions: Better alignment instruments, pre-operative planning techniques, and operation protocols are needed for shoulder prostheses. The training of resident surgeons should be focused on the exposure phase, the alignment of the humeral head, the exposure of the glenoid, and the alignment of the glenoid. Evaluating the surgical process using time-action analysis can be used to determine the limitations during surgical procedures. Furthermore, it shows the large variation in factors affecting surgical performance, indicating that a system approach is needed to improve surgical outcome.</p

Decoupling of functional and structural language networks in temporal lobe epilepsy

OBJECTIVE: To identify functional and structural alterations in language networks of people with temporal lobe epilepsy (TLE), who frequently present with naming and word-finding difficulties. METHODS: Fifty-five patients with unilateral TLE (29 left) and 16 controls were studied with auditory and picture naming functional magnetic resonance imaging (fMRI) tasks. Activation maxima in the left posterobasal temporal lobe were used as seed regions for whole-brain functional connectivity analyses (psychophysiological interaction). White matter language pathways were investigated using diffusion tensor imaging and neurite orientation dispersion and density imaging metrics extracted along fiber bundles starting from fMRI-guided seeds. Regression analyses were performed to investigate the correlation of functional connectivity with diffusion MRI metrics. RESULTS: In the whole group of patients and controls, weaker functional connectivity from the left posterobasal temporal lobe (1) to the bilateral anterior temporal lobe, precentral gyrus, and lingual gyrus during auditory naming and (2) to the bilateral occipital cortex and right fusiform gyrus during picture naming was associated with decreased neurite orientation dispersion and higher free water fraction of white matter tracts. Compared to controls, TLE patients exhibited fewer structural connections and an impaired coupling of functional and structural metrics. SIGNIFICANCE: TLE is associated with an impairment and decoupling of functional and structural language networks. White matter damage, as evidenced by diffusion abnormalities, may contribute to impaired functional connectivity and language dysfunction in TLE

Hippocampal profiling: Localized magnetic resonance imaging volumetry and T2 relaxometry for hippocampal sclerosis

Objective: Hippocampal sclerosis (HS) is the most common cause of drug‐resistant temporal lobe epilepsy, and its accurate detection is important to guide epilepsy surgery. Radiological features of HS include hippocampal volume loss and increased T2 signal, which can both be quantified to help improve detection. In this work, we extend these quantitative methods to generate cross‐sectional area and T2 profiles along the hippocampal long axis to improve the localization of hippocampal abnormalities. Methods: T1‐weighted and T2 relaxometry data from 69 HS patients (32 left, 32 right, 5 bilateral) and 111 healthy controls were acquired on a 3‐T magnetic resonance imaging (MRI) scanner. Automated hippocampal segmentation and T2 relaxometry were performed and used to calculate whole‐hippocampal volumes and to estimate quantitative T2 (qT2) values. By generating a group template from the controls, and aligning this so that the hippocampal long axes were along the anterior‐posterior axis, we were able to calculate hippocampal cross‐sectional area and qT2 by a slicewise method to localize any volume loss or T2 hyperintensity. Individual patient profiles were compared with normative data generated from the healthy controls. Results: Profiling of hippocampal volumetric and qT2 data could be performed automatically and reproducibly. HS patients commonly showed widespread decreases in volume and increases in T2 along the length of the affected hippocampus, and focal changes may also be identified. Patterns of atrophy and T2 increase in the left hippocampus were similar between left, right, and bilateral HS. These profiles have potential to distinguish between sclerosis affecting volume and qT2 in the whole or parts of the hippocampus, and may aid the radiological diagnosis in uncertain cases or cases with subtle or focal abnormalities where standard whole‐hippocampal measurements yield normal values. Significance: Hippocampal profiling of volumetry and qT2 values can help spatially localize hippocampal MRI abnormalities and work toward improved sensitivity of subtle focal lesions

FLAIR-only joint volumetric analysis of brain lesions and atrophy in clinically isolated syndrome (CIS) suggestive of multiple sclerosis

Background: MRI assessment in multiple sclerosis (MS) focuses on the presence of typical white matter (WM) lesions. Neurodegeneration characterised by brain atrophy is recognised in the research field as an important prognostic factor. It is not routinely reported clinically, in part due to difficulty in achieving reproducible measurements. Automated MRI quantification of WM lesions and brain volume could provide important clinical monitoring data. In general, lesion quantification relies on both T1 and FLAIR input images, while tissue volumetry relies on T1. However, T1-weighted scans are not routinely included in the clinical MS protocol, limiting the utility of automated quantification. Objectives: We address an aspect of this important translational challenge by assessing the performance of FLAIR-only lesion and brain segmentation, against a conventional approach requiring multi-contrast acquisition. We explore whether FLAIR-only grey matter (GM) segmentation yields more variability in performance compared with two-channel segmentation; whether this is related to field strength; and whether the results meet a level of clinical acceptability demonstrated by the ability to reproduce established biological associations. Methods: We used a multicentre dataset of subjects with a CIS suggestive of MS scanned at 1.5T and 3T in the same week. WM lesions were manually segmented by two raters, ‘manual 1′ guided by consensus reading of CIS-specific lesions and ‘manual 2′ by any WM hyperintensity. An existing brain segmentation method was adapted for FLAIR-only input. Automated segmentation of WM hyperintensity and brain volumes were performed with conventional (T1/T1 + FLAIR) and FLAIR-only methods. Results: WM lesion volumes were comparable at 1.5T between ‘manual 2′ and FLAIR-only methods and at 3T between ‘manual 2′, T1 + FLAIR and FLAIR-only methods. For cortical GM volume, linear regression measures between conventional and FLAIR-only segmentation were high (1.5T: α = 1.029, R2 = 0.997, standard error (SE) = 0.007; 3T: α = 1.019, R2 = 0.998, SE = 0.006). Age-associated change in cortical GM volume was a significant covariate in both T1 (p = 0.001) and FLAIR-only (p = 0.005) methods, confirming the expected relationship between age and GM volume for FLAIR-only segmentations. Conclusions: FLAIR-only automated segmentation of WM lesions and brain volumes were consistent with results obtained through conventional methods and had the ability to demonstrate biological effects in our study population. Imaging protocol harmonisation and validation with other MS phenotypes could facilitate the integration of automated WM lesion volume and brain atrophy analysis as clinical tools in radiological MS reporting

Patient-reported outcomes after 10-year follow-up of intensive, multifactorial treatment in individuals with screen-detected type 2 diabetes: the ADDITION-Europe trial.

AIMS: To present the longer-term impact of multifactorial treatment of type 2 diabetes on self-reported health status, diabetes-specific quality of life, and diabetes treatment satisfaction at 10-year follow up of the ADDITION-Europe trial. METHODS: The ADDITION-Europe trial enrolled 3057 individuals with screen-detected type 2 diabetes from four centres [Denmark, the UK (Cambridge and Leicester) and the Netherlands], between 2001 and 2006. Participants were randomized at general practice level to intensive treatment or to routine care . The trial ended in 2009 and a 10-year follow-up was performed at the end of 2014. We measured self-reported health status (36-item Short-Form Health Survey and EQ-5D), diabetes-specific quality of life (Audit of Diabetes-Dependent Quality of Life questionnaire), and diabetes treatment satisfaction (Diabetes Treatment Satisfaction Questionnaire) at different time points during the study period. A mixed-effects model was applied to estimate the effect of intensive treatment (intention-to-treat analyses) on patient-reported outcome measures for each centre. Centre-specific estimates were pooled using a fixed effects meta-analysis. RESULTS: There was no difference in patient-reported outcome measures between the routine care and intensive treatment arms in this 10-year follow-up study [EQ-5D: -0.01 (95% CI -0.03, 0.01); Physical Composite Score (36-item Short-Form Health Survey): -0.27 (95% CI -1.11, 0.57), Audit of Diabetes-Dependent Quality of Life questionnaire: -0.01 (95% CI -0.11, 0.10); and Diabetes Treatment Satisfaction Questionnaire: -0.20 (95% CI -0.70, 0.29)]. CONCLUSIONS: Intensive, multifactorial treatment of individuals with screen-detected type 2 diabetes did not affect self-reported health status, diabetes-specific quality of life, or diabetes treatment satisfaction at 10-year follow-up compared to routine care

Chytrid epidemics may increase genetic diversity of a diatom spring-bloom

Contrary to expectation, populations of clonal organisms are often genetically highly diverse. In phytoplankton, this diversity is maintained throughout periods of high population growth (that is, blooms), even though competitive exclusion among genotypes should hypothetically lead to the dominance of a few superior genotypes. Genotype-specific parasitism may be one mechanism that helps maintain such high-genotypic diversity of clonal organisms. Here, we present a comparison of population genetic similarity by estimating the beta-dispersion among genotypes of early and peak bloom populations of the diatom Asterionella formosa for three spring-blooms under high or low parasite pressure. The Asterionella population showed greater beta-dispersion at peak bloom than early bloom in the 2 years with high parasite pressure, whereas the within group dispersion did not change under low parasite pressure. Our findings support that high prevalence parasitism can promote genetic diversification of natural populations of clonal hosts