-
Hamilton Carrillo posted an update 1 year, 6 months ago
Anthrax toxin is a tripartite virulence factor produced by Bacillus anthracis during infection. Under acidic endosomal pH conditions, the toxin’s protective antigen (PA) component forms a transmembrane channel in host cells. The PA channel then translocates its two enzyme components, lethal factor and edema factor, into the host cytosol under the proton motive force. Protein translocation under a proton motive force is catalyzed by a series of nonspecific polypeptide binding sites, called clamps. A 10-residue guest/host peptide model system, KKKKKXXSXX, was used to functionally probe polypeptide-clamp interactions within wild-type PA channels. The guest residues were Thr, Ala, Leu, Phe, Tyr, and Trp. In steady-state translocation experiments, the channel blocked most tightly with peptides that had increasing amounts of nonpolar surface area. Cooperative peptide binding was observed in the Trp-containing peptide sequence but not the other tested sequences. Trp substitutions into a flexible, uncharged linker between the lethal factor amino-terminal domain and diphtheria toxin A chain expedited translocation. Therefore, peptide-clamp sites in translocase channels can sense large steric features (like tryptophan) in peptides, and while these steric interactions may make a peptide translocate poorly, in the context of folded domains, they can make the protein translocate more rapidly presumably via a hydrophobic steric ratchet mechanism.
The ‘Study of Intravenous Autologous Marrow in Multiple Sclerosis (SIAMMS)’ trial was a safety and feasibility study which examined the effect of intravenous infusion of autologous bone marrow without myeloablative therapy. This trial was well tolerated and improvement was noted in the global evoked potential (GEP)–a neurophysiological secondary outcome measure recording speed of conduction in central nervous system pathways. The efficacy of intravenous delivery of autologous marrow in progressive multiple sclerosis (MS) will be examined in the phase II study the ‘Assessment of Bone Marrow-Derived Cellular Therapy in Progressive Multiple Sclerosis (ACTiMuS; NCT01815632)’. In parallel with the ‘ACTiMuS’ study, the current study ‘SIAMMS-II’ will explore the feasibility of repeated, non-myeloablative autologous bone marrow-derived cell therapy in progressive MS. Furthermore, information will be obtained regarding the persistence or otherwise of improvements in conduction in central nervous system pathways observed in the original ‘SIAMMS’ study and whether these can be reproduced or augmented by a second infusion of autologous bone marrow-derived cells.
An open, prospective, single-centre phase I extension study. The six patients with progressive MS who participated in the ‘SIAMMS’ study will be invited to undergo repeat bone marrow harvest and receive an intravenous infusion of autologous, unfractionated bone marrow as a day-case procedure. The primary outcome measure is the number of adverse events, and secondary outcome measures will include change in clinical rating scales of disability, GEP and cranial MRI.
The study has UK National Research Ethics Committee approval (13/SW/0255). 4-Phenylbutyric acid mouse Study results will be disseminated via peer-reviewed publications and conference presentations.
NCT01932593.
NCT01932593.
To improve measurement precision, the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Group is developing an item bank for computerized adaptive testing (CAT) of emotional functioning (EF). The item bank will be within the conceptual framework of the widely used EORTC Quality of Life questionnaire (QLQ-C30).
On the basis of literature search and evaluations by international samples of experts and cancer patients, 38 candidate items were developed. The psychometric properties of the items were evaluated in a large international sample of cancer patients. This included evaluations of dimensionality, item response theory (IRT) model fit, differential item functioning (DIF), and of measurement precision/statistical power.
Responses were obtained from 1,023 cancer patients from four countries. The evaluations showed that 24 items could be included in a unidimensional IRT model. DIF did not seem to have any significant impact on the estimation of EF. Evaluations indicated that the CAT measure may reduce sample size requirements by up to 50% compared to the QLQ-C30 EF scale without reducing power.
On the basis of thorough psychometric evaluations, we have established an EF item bank of 24 items. This will allow for more precise and flexible measurement of EF, while maintaining backward compatibility with the QLQ-C30 EF scale.
On the basis of thorough psychometric evaluations, we have established an EF item bank of 24 items. This will allow for more precise and flexible measurement of EF, while maintaining backward compatibility with the QLQ-C30 EF scale.Precise evaluation of the ascending reticular activating system (ARAS) is important for diagnosis, prediction of prognosis, and management of patients with disorders of impaired consciousness. In the current study, we attempted to reconstruct the direct neural pathway between the brainstem reticular formation (RF) and the cerebral cortex in normal subjects, using diffusion tensor imaging (DTI). Forty-one healthy subjects were recruited for this study. DTIs were performed using a sensitivity-encoding head coil at 1.5Tesla with FMRIB Software Library. For connectivity of the brainstem RF, we used two regions of interest (ROIs) for the brainstem RF (seed ROI) and the thalamus and hypothalamus (exclusion ROI). Connectivity was defined as the incidence of connection between the brainstem RF and target brain regions at the threshold of 5 and 50 streamlines. Regarding the thresholds of 5 and 50, the brainstem RF showed high connectivity to the lateral prefrontal cortex (lPFC, 67.1% and 20.7%) and ventromedial prefrontal cortex (vmPFC, 50.0% and 18.3%), respectively. In contrast, the brainstem RF showed low connectivity to the primary motor cortex (31.7% and 3.7%), premotor cortex (24.4% and 3.7%), primary somatosensory cortex (23.2% and 2.4%), orbitofrontal cortex (17.1% and 7.3%), and posterior parietal cortex (12.2% and 0%), respectively. The brainstem RF was mainly connected to the prefrontal cortex, particularly lPFC and vmPFC. We believe that the methodology and results of this study would be useful to clinicians involved in the care of patients with impaired consciousness and researchers in studies of the ARAS.
Osteonecrosis of the femoral head may be a disease resulting from abnormal proliferation or differentiation of mesenchymal stem cells. The present investigation explored the novel strategy of hypoxia-preconditioned BMMSCs to reverse the impairment of osteonecrosis BMMSCs and enhance the therapeutic potential of hypoxia-treated BMMSC transplantation.
BMMSCs from the anterior superior iliac spine region of osteonecrosis rabbit were cultured under 20% O2 or 2% O2 conditions. Normal BMMSCs were cultured under 20% O2 condition as control. Growth factors secreted were examined by enzyme-linked immunosorbent assay. 20% O2 or 2% O2 BMMSCs were injected into the femoral head of rabbits after core decompression. Cell viability and apoptosis were assessed in vitro, and TUNEL staining of the femoral head was analyzed after transplantation. Angiogenesis (capillary-like structure formation, CD31 immunohistochemical staining and ink infusion angiography) and osteogenesis (Alizarin red-S staining, micro-CT scanning and Oreconditioning of BMMSCs is an effective means of reversing the impairment of osteonecrosis BMMSCs, promoting their regenerative capability and therapeutic potential for the treatment of osteonecrosis.
Vessel remodelling is commonly observed in coronary atherosclerosis, but factors influencing remodelling, such as plaque lipid content, remain poorly described.
Remodelling index (RI) was calculated as the ratio of lesion to proximal and distal references external membrane area and was categorized as follows positive (PR; RI > 1.05), intermediate (IR; RI 0.95-1.05), and negative remodelling (NR; RI < 0.95). RI was studied by near-infrared spectroscopy (NIRS) as a function of lipid content metrics, including the maximal 4 mm lipid core burden index of the segment (maxLCBI4 mm) and intravascular ultrasound (IVUS) lesion plaque burden (PB). The authors further stratified the analysis according to obstructive (≥50%) and non-obstructive (<50%) lesions using quantitative coronary angiography. Receiver-operating characteristic curves were performed to describe the maxLCBI4 mm level associated with PR. From May 2012 to November 2014, 100 de novo lesions from 67 patients underwent simultaneous NIRS-IVUS. y aid in further stratifying vulnerable lesions.
To evaluate the construct validity and interrater reliability of 4 simple antigravity tests in a small group of patients with facioscapulohumeral muscular dystrophy (FSHD).
Case-control study.
University medical center.
Patients with various severity levels of FSHD (n=9) and healthy control subjects (n=10) were included (N=19).
Not applicable.
A 4-point ordinal scale was designed to grade performance on the following 4 antigravity tests sit to stance, stance to sit, step up, and step down. In addition, the 6-minute walk test, 10-m walking test, Berg Balance Scale, and timed Up and Go test were administered as conventional tests. Construct validity was determined by linear regression analysis using the Clinical Severity Score (CSS) as the dependent variable. Interrater agreement was tested using a κ analysis.
Patients with FSHD performed worse on all 4 antigravity tests compared with the controls. Stronger correlations were found within than between test categories (antigravity vs conventional). The antigravity tests revealed the highest explained variance with regard to the CSS (R(2)=.86, P=.014). Interrater agreement was generally good.
The results of this exploratory study support the construct validity and interrater reliability of the proposed antigravity tests for the assessment of functional capacity in patients with FSHD taking into account the use of compensatory strategies. Future research should further validate these results in a larger sample of patients with FSHD.
The results of this exploratory study support the construct validity and interrater reliability of the proposed antigravity tests for the assessment of functional capacity in patients with FSHD taking into account the use of compensatory strategies. Future research should further validate these results in a larger sample of patients with FSHD.Glioma is a common type of primary brain tumour, with a strongly invasive potential, often exhibiting non-uniform, highly irregular growth. This makes it difficult to assess the degree of extent of the tumour, hence bringing about a supplementary challenge for the treatment. It is therefore necessary to understand the migratory behaviour of glioma in greater detail. In this paper, we propose a multiscale model for glioma growth and migration. Our model couples the microscale dynamics (reduced to the binding of surface receptors to the surrounding tissue) with a kinetic transport equation for the cell density on the mesoscopic level of individual cells. On the latter scale, we also include the proliferation of tumour cells via effects of interaction with the tissue. An adequate parabolic scaling yields a convection-diffusion-reaction equation, for which the coefficients can be explicitly determined from the information about the tissue obtained by diffusion tensor imaging (DTI). Numerical simulations relying on DTI measurements confirm the biological findings that glioma spread along white matter tracts.
Home Activity










