Quantitative grip force assessment of muscular weakness in chronic inflammatory demyelinating polyneuropathy

Background: In patients suffering from Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) disease severity is assessed by Medical Research Counsil (MRC) Scale or Inflammatory Neuropathy Cause and Treatment (INCAT) disability score. However, none of these methods is appropriate to objectively assess muscle weakness or to detect very small subclinical changes. More objective and quantitative measures are needed in order to evaluate treatment efficiency or to detect subclinical affection of upper limps for early diagnosis. The goal of our study was to objectively quantify muscular weakness in CIDP patients with the non-invasive Quantitative Motor (Q-Motor) test of Grip Force Assessment (QGFA) as well as the Involuntary Movement Assessment (QIMA) and to search for differences between typical and atypical CIDP variants. In addition, we hypothesized that Q-Motor findings correlate with disease severity scales such as MRC or INCAT score. Methods: In this cross-sectional exploratory proof-of-concept study subjects with confirmed diagnosis of typical or atypical CIDP were examined and compared to healthy controls (HC). For Q-Motor tests all subjects had to lift a device (250 g and 500 g) equipped with an electromagnetic sensor that measured grip force (GF) and three-dimensional changes in position and orientation. The measures "grip force variability" (GFV), "position index" (PI) and "orientation index" (OI) were provided to assess involuntary movements due to muscular weakness. Results: 33 patients with CIDP and 28 HC were included. All measures were significantly elevated in CIDP patients for both devices in the right and left hand compared to healthy controls. Subgroup analysis revealed no differences between typical and atypical CIDP variants. INCAT score only weakly correlated with OI and PI. However, there was a stronger correlation between MRC and QIMA parameters in both hands. Conclusion: Q-Motor assessments were capable to objectively assess muscular weakness in CIDP. In particular, QIMA measures detected subclinical generalized muscle weakness even in patients with milder disability. Sensitivity and rater-independence of Q-Motor assessments support a further exploration of QIMA measures as potential endpoints for future clinical trials in CIDP

Matrix biochemistry and cell biology of dedifferentiated chondrosarcomas

Dedifferentiated chondrosarcoma is an uncommon mesenchymal neoplasm comprised of two different components, low-grade conventional chondrosarcoma and high-grade non-cartilaginous sarcoma. In order to gain better insight into the biology of this tumor, we investigated a large series of dedifferentiated chondrosarcomas by looking at the composition of the extracellular tumor matrix within each of the distinct histological components. Our results showed that the well-differentiated portion of the tumors showed matrix components largely similar to conventional chondrosarcomas or enchondromas. In contrast, the high-grade portions showed a variety of staining patterns related to the matrix being formed. Cartilage-specific proteoglycans and collagens were consistently absent, except in areas showing a chondroblastic osteosarcoma histomorphology. Instead, the most dominant immunostaining was received for type I collagen. Type III and VI collagens were concentrated in the areas showing a fibroblastic phenotype. Our results lend further support to the notion that dedifferentiated chondrosarcoma represents transdifferentiation of a cell towards various blastic mesenchymal cell lineages, most commonly osteoblastic and fibroblastic, but occasionally chondroblastic as well. There was no difference in the clinical outcome of patients with differing high-grade tumor types, emphasizing that grade is a more important predictor of biological behavior than the direction of tumor differentiation.Molecular tumour pathology - and tumour genetic

NF-κB essential modulator (NEMO) interaction with linear and Lys-63 ubiquitin chains contributes to NF-κB activation.

The IκB kinase (IKK) complex acts as a gatekeeper of canonical NF-κB signaling in response to upstream stimulation. IKK activation requires sensing of ubiquitin chains by the essential IKK regulatory subunit IKKγ/NEMO. However, it has remained enigmatic whether NEMO binding to Lys-63-linked or linear ubiquitin chains is critical for triggering IKK activation. We show here that the NEMO C terminus, comprising the ubiquitin binding region and a zinc finger, has a high preference for binding to linear ubiquitin chains. However, immobilization of NEMO, which may be reminiscent of cellular oligomerization, facilitates the interaction with Lys-63 ubiquitin chains. Moreover, selective mutations in NEMO that abolish association with linear ubiquitin but do not affect binding to Lys-63 ubiquitin are only partially compromising NF-κB signaling in response to TNFα stimulation in fibroblasts and T cells. In line with this, TNFα-triggered expression of NF-κB target genes and induction of apoptosis was partially compromised by NEMO mutations that selectively impair the binding to linear ubiquitin chains. Thus, in vivo NEMO interaction with linear and Lys-63 ubiquitin chains is required for optimal IKK activation, suggesting that both type of chains are cooperating in triggering canonical NF-κB signaling

Photoreceptor layer thinning in idiopathic Parkinson's disease

This study was undertaken to quantify retinal and intra-retinal layer thicknesses in Parkinson's disease (PD), and to evaluate whether retinal structural changes may be related to altered discrimination of color vision and to severity and duration of PD disease. We examined 97 PD patients and 32 healthy controls (HC) with spectral-domain optical coherence tomography (OCT), including intra-retinal layer segmentation. In total, we compared 111 retinal nerve fiber layer (RNFL)-scans and 114 macula scans from 68 PD patients with 62 RNFL and 63 macula scans from 32 HC. For clinical evaluation of disease severity, we used the Unified Parkinson's Disease Rating Scale (UPDRS) motor examination. To determine color discrimination, we performed the Farnsworth Munsell 100 Hue Test (FMT) in a subgroup of PD patients. We found significant combined outer nuclear and photoreceptor layer thinning in PD versus HC (118.6 vs. 123.5 µm, P = 0.001). Differences in RNFL, total macular volume, or the other retinal layer thicknesses were not detected. The OCT measures were not associated with disease severity, duration, or color vision. By showing photoreceptor cell layer thinning, our findings support previous in vivo and autopsy studies demonstrating retinal alterations in PD. Optical coherence tomography may help to assess morphological retinal changes in PD patients; however, the utility of OCT in routine clinical practice may be limited because many PD patients have difficulties complying with OCT investigation because of disease-related symptoms such as tremor, axial rigidity, or cognitive impairment

Quantitative RNA imaging in single live cells reveals age-dependent asymmetric inheritance.

Asymmetric inheritance of cellular content through cell division plays an important role in cell viability and fitness. The dynamics of RNA segregation are so far largely unaddressed. This is partly due to a lack of approaches to follow RNAs over multiple cellular divisions. Here, we establish an approach to quantify RNA dynamics in single cells across several generations in a microfluidics device by tagging RNAs with the diSpinach aptamer. Using S. cerevisiae as a model, we quantitatively characterize intracellular RNA transport from mothers into their buds. Our results suggest that, at cytokinesis, ENO2 diSpinach RNA is preferentially distributed to daughters. This asymmetric RNA segregation depends on the lifespan regulator Sir2 and decreases with increasing replicative age of mothers but does not result from increasing cell size during aging. Overall, our approach opens more opportunities to study RNA dynamics and inheritance in live budding yeast at the single-cell level

Identification of Small-Molecule Frequent Hitters of Glutathione S-Transferase-Glutathione Interaction

In high-throughput screening (HTS) campaigns, the binding of glutathione S-transferase (GST) to glutathione (GSH) is used for detection of GST-tagged proteins in protein-protein interactions or enzyme assays. However, many false-positives, so-called frequent hitters (FH), arise that either prevent GST/GSH interaction or interfere with assay signal generation or detection. To identify GST-FH compounds, we analyzed the data of five independent AlphaScreen-based screening campaigns to classify compounds that inhibit the GST/GSH interaction. We identified 53 compounds affecting GST/GSH binding but not influencing His-tag/Ni2+-NTA interaction and general AlphaScreen signals. The structures of these 53 experimentally identified GST-FHs were analyzed in chemoinformatic studies to categorize substructural features that promote interference with GST/GSH binding. Here, we confirmed several existing chemoinformatic filters and more importantly extended them as well as added novel filters that specify compounds with anti-GST/GSH activity. Selected compounds were also tested using different antibody-based GST detection technologies and exhibited no interference clearly demonstrating specificity toward their GST/GSH interaction. Thus, these newly described GST-FH will further contribute to the identification of FH compounds containing promiscuous substructures. The developed filters were uploaded to the OCHEM website (http://ochem.eu) and are publicly accessible for analysis of future HTS results