In order to pass through the microcirculation, red blood cells (RBCs) need to undergo extensive deformations and to recover the original shape. This extreme deformability is altered by various ...pathological conditions. On the other hand, an altered RBC deformability can have major effects on blood flow and can lead to pathological implications. The study of the viscoelastic response of red blood cells to mechanical stimuli is crucial to fully understand deformability changes under pathological conditions. However, the typical erythrocyte biconcave shape hints to a complex and intrinsically heterogeneous mechanical response that must be investigated by using probes at the nanoscale level. In this work, the local viscoelastic behaviour of healthy and pathological red blood cells was probed by Atomic Force Microscopy (AFM). Our results clearly show that the RBC stiffness is not spatially homogeneous, suggesting a strong correlation with the erythrocyte biconcave shape. Moreover, our nanoscale mapping highlights the key role played by viscous forces, demonstrating that RBCs do not behave as pure elastic bodies. The fundamental role played by viscous forces is further strengthened by the comparison between healthy and pathological (diabetes mellitus) RBCs. It is well known that pathological RBCs are usually stiffer than the healthy ones. Our measures unveil a more complex scenario according to which the difference between normal and pathological red blood cells does not merely lie in their stiffness but also in a different dynamical response to external stimuli that is governed by viscous forces.
SW480 and SW620 colon carcinoma cell lines derive from primary tumour and lymph-node metastasis of the same patient, respectively. For this reason, these cells represent an ideal system to analyse ...phenotypic variations associated with the metastatic process. In this study we analysed SW480 and SW620 cytoskeleton remodelling by measuring the cells' mechanics and morphological properties using different microscopic techniques. We observed that different specialized functions of cells, i.e. the capacity to metastasize of elongated cells inside the primary tumour and the ability to intravasate and resist shear forces of the stream of cells derived from lymph node metastasis, are reflected in their mechanical properties. We demonstrated that, together with stiffness and adhesion between the AFM tip and the cell surface, cell shape, actin organization and surface roughness are strictly related and are finely modulated by colorectal cancer cells to better accomplish their specific tasks in cancer growth and invasion.
Summary
Several reports have highlighted the abnormal increments of serum immunoglobulin free light chains (FLCs) in the course of systemic autoimmune rheumatic diseases (SARD), but a comparative ...analysis among different conditions is still lacking. A strong association between elevated FLC and hepatitis C virus (HCV)‐related mixed cryoglobulinaemia (HCVMC) has been well established. Here, we aimed to analyse serum FLC levels in patients with four different SARD in comparison with HCVMC. Using a turbidimetric assay, free κ and λ chains were quantified in sera from 198 SARD patients (37 rheumatoid arthritis, RA; 47 systemic lupus erythematosus, SLE; 52 anti‐phospholipid syndrome, APS; 62 primary Sjogren's syndrome, pSS), 62 HCVMC and 50 healthy blood donors (HD). All patient groups showed increased κ levels when compared to HD: 33·5 ± 2·6 mg/l in HCVMC, 26·7 ± 2·3 mg/l in RA, 29·7 ± 1·9 mg/l in SLE, 23·8 ± 1·1 mg/l in APS, 24·2 ± 1·1 mg/l in pSS; 10·1 ± 0·6 mg/l in HD. Free λ levels displayed a significant increase only for HCVMC (20·4 ± 1·4 mg/l) and SLE (18·4 ± 1·0 mg/l) compared to HD (13·6 ± 0·9 mg/l). The increase of κ compared to λ takes into account a κ /λ ratio of 1·6 for all groups. Our results substantially analyse and strengthen the association between FLC and SARD focusing the questions regarding their role in the pathogenesis and diagnosis of human diseases. Unfortunately, the biochemical differences distinguishing normal from pathological FLC have not been identified. Production of different isotypes is probably connected to still‐unknown pathways.
Our study confirms the occurrence of abnormal increases of immunoglobulin free light chains (FLC) in systemic autoimmune rheumatic diseases (SARD), with a comparative analysis of serum levels in four different disorders. Our results strongly suggest that the addition of FLC analysis in routine panels can improve the quality of laboratory diagnosis, offering physicians a direct viewpoint on B‐cell activation. Based on our data and well‐demonstrated biological properties, we hypothesize the pathogenic potential of FLCs that could act as ‘mini autoantibodies'.
The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft ...matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.
Increasing evidence is available about the presence of increased serum concentration of immunoglobulin (Ig) free light chains (FLCs) in both atopic and non-atopic inflammatory diseases, including ...severe asthma, providing a possible new biomarker of disease.
We analyzed clinical and laboratory data, including FLCs, obtained from a cohort of 79 asthmatic subjects, clinically classified into different GINA steps. A control group of 40 age-matched healthy donors (HD) was considered. Particularly, HD have been selected according to the absence of monoclonal components (in order to exclude paraproteinemias), were tested for total IgE (that were in the normal ranges) and were negative for aeroallergens specific IgE. Moreover, no abnormality of common inflammatory markers (i.e., erythrocyte sedimentation rate and C-reactive protein) was detectable.
FLC-k levels were significantly increased in the asthmatic population, compared to the control group. Despite the absence of statistically significant differences in FLC-λ levels, the FLC-k/FLC-λ ratio displayed remarkable differences between the two groups. A positive correlation between FLC-κ and FLC-λ levels was found. FLC- λ level displayed a significant negative correlation with the FEV1 value. Moreover, the FLC-κ /FLC- λ ratio was negatively correlated with the SNOT-22 score and a positive correlation was observed between FLCs and Staphylococcus Aureus IgE enterotoxins sensitization.
Our findings confirmed the role of FLCs in asthma as a potential biomarker in an inflammatory disease characterized by different endotypes and phenotypes. In particular, FLC-κ and FLC-k/FLC-λ ratio could be a qualitative indicator for asthma, while FLC-λ levels could be a quantitative indicator for clinical severity parameters.
The present paper concerns a new description of changing in metabolism during incremental exercises test that permit an individually tailored program of exercises for obese subjects. We analyzed ...heart rate variability from RR interval time series (tachogram) with an alternative approach, the recurrence quantification analysis, that allows a description of a time series in terms of its dynamic structure and is able to identify the phase transitions. A transition in cardiac signal dynamics was detected and it perfectly reflects the aerobic threshold, as identified by gas exchange during an incremental exercise test, revealing the coupling from the respiratory system toward the heart. Moreover, our analysis shows that, in the recurrence plot of RR interval, it is possible to identify a specific pattern that allows to identify phase transitions between different dynamic regimes. The perfect match of the occurrence of the phase transitions with changes observed in the VO
consumption, the gold standard approach to estimate thresholds, strongly supports the possibility of using our analysis of RR interval to detect metabolic threshold. In conclusion, we propose a novel nonlinear data analysis method that allows for an easy and personalized detection of thresholds both from professional and even from low-cost wearable devices, without the need of expensive gas analyzers.
Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for serious hospital infections worldwide and represents a global public health problem. Curcumin, the major constituent of turmeric, ...is effective against MRSA but only at cytotoxic concentrations or in combination with antibiotics. The major issue in curcumin-based therapies is the poor solubility of this hydrophobic compound and the cytotoxicity at high doses. In this paper, we describe the efficacy of a composite nanoparticle made of curcumin (CU) and graphene oxide (GO), hereafter GOCU, in MRSA infection treatment. GO is a nanomaterial with a large surface area and high drug-loading capacity. GO has also antibacterial properties due mainly to a mechanical cutting of the bacterial membranes. For this physical mechanism of action, microorganisms are unlikely to develop resistance against this nanomaterial. In this work, we report the capacity of GO to support and stabilize curcumin molecules in a water environment and we demonstrate the efficacy of GOCU against MRSA at a concentration below 2 µg ml−1. Further, GOCU displays low toxicity on fibroblasts cells and avoids haemolysis of red blood cells. Our results indicate that GOCU is a promising nanomaterial against antibiotic-resistant MRSA.
Intensive research on the bio-applications of graphene and its derivatives is leading to many technological applications. Graphene Oxide (GO), for its unique 2-D structure and its physical/chemical ...properties, has attracted increasing interest over the last few years in the fields of drug/gene delivery, biological imaging and antibacterial treatments. Together with these great potentials for biomedical applications, several aspects of graphene toxicity mechanisms including oxidative stress, cutting off intracellular metabolic routes and cell membrane rupture must be carefully evaluated. In this work we demonstrate that the GO flakes, able to disrupt the erythrocyte plasma membrane, greatly reduce their hemolytic activity after interacting with plasma proteins.
GO flakes, able to disrupt the erythrocyte plasma membrane, greatly reduce their haemolytic activity after interacting with plasma proteins. Haemolysis activity increases inversely to the GO flakes size.
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The structure and organization of the Type I collagen microfibrils during mineral nanoparticle formation appear as the key factor for a deeper understanding of the biomineralization ...mechanism and for governing the bone tissue physical properties. In this work we investigated the dynamics of collagen packing during ex-vivo mineralization of ceramic porous hydroxyapatite implant scaffolds using synchrotron high resolution X-ray phase contrast micro-tomography (XPCμT) and synchrotron scanning micro X-ray diffraction (SμXRD). While XPCμT provides the direct 3D image of the collagen fibers network organization with micrometer spatial resolution, SμXRD allows to probe the structural statistical fluctuations of the collagen fibrils at nanoscale. In particular we imaged the lateral spacing and orientation of collagen fibrils during the anisotropic growth of mineral nanocrystals. Beyond throwing light on the bone regeneration multiscale process, this approach can provide important information in the characterization of tissue in health, aging and degeneration conditions.
BONE grafts are the most common transplants after the blood transfusions. This makes the bone-tissue regeneration research of pressing scientific and social impact.
Bone is a complex hierarchical structure, where the interplay of organic and inorganic mineral phases at different length scale (from micron to atomic scale) affect its functionality and health. Thus, the understanding of bone tissue regeneration requires to image its spatial-temporal evolution (i) with high spatial resolution and (ii) at different length scale.
We exploited high spatial resolution X-ray Phase Contrast micro Tomography and Scanning micro X-ray Diffraction in order to get new insight on the engineered tissue formation mechanisms. This approach could open novel routes for the early detection of different degenerative conditions of tissue.
Summary
In physiological conditions, red blood cells (RBCs) are capable of dramatic deformations when passing through the microvasculature. This extreme deformability is closely related to the RBC ...biconcave shape, to the fluidic nature of the haemoglobin and the cell membrane structure, primarily consisting of a phospholipid bilayer with an underlying two‐dimensional spectrin network. In many pathological and inflammatory conditions, the shape and the extreme deformability of erythrocytes appear to be significantly altered. These findings have stimulated intense research towards the search and validation of novel erythrocyte‐based mechanical biomarkers, useful for disease diagnosis and therapy monitoring. In this study, we investigated with Atomic Force Microscopy (AFM) the mechanical properties of erythrocytes obtained from a 68 years old cirrhotic man diagnosed with spur cell anaemia and cold agglutinated disease, before and after liver transplantation. Mechanical changes are compared with ultrastructural alterations as studied by scanning electron microscopy and discussed according to confocal fluorescence microscopy results, showing possible alterations induced by the cirrhotic environment at the level of the RBCs cytoskeletal organisation and lipidic composition. Taken together, the results here presented show that liver transplantation not only contributes to restoring the proper RBC morphology, but it also induces recovery of the physiological viscous behaviour of cells, further stressing the relevance of viscous and dissipative forces in determining the RBC biomechanical response.
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