RESTORATION OF ERYTHROCYTE MORPHOLOGY AFTER CRYOPRESERVATION

During the erythrocyte transfusion, a significant part of the cells (~ 25%) is utilized by the spleen and liver in a day due to the deformations and damage to cell membranes that resulted from the hypothermic storage or cryopreservation. An increase in free iron in the blood during the decomposition of red blood cells leads to the stimulation of oxidative stress and inflammation, as well as to dysfunction of the main organs. The primary indicator of damage to the membranes of erythrocytes can be detected through the changes in their morphology. The work investigated the morphological characteristics of erythrocytes after cryopreservation in a medium containing PEG-1500 and 1,2-PD. Erythrocytes washed after thawing and suspended in an isotonic NaCl solution are represented by echinocytes, at the same time, when placed into a solution with albumin, the cells demonstrate the restoration of their discoid shape. According to the well-established concept, the regulation of the shape of erythrocytes is determined by a change in the conformation of the anionic carrier, which is formed by the main integral membrane protein, the protein of band 3. The study has shown that the treatment of erythrocytes with DIDS, which leads to the fixation of the conformation of the carrier with the transport site facing the outer side of the membrane, does not change the morphomodulatory effect of albumin. At the same time, with a decrease in the medium pH, when the albumin charge approaches zero, its effect is eliminated. The results obtained suggest that, upon freezing-thawing of erythrocytes, the deterioration of hydrophobic interactions of transmembrane segments of the protein of band 3 is accompanied by a change in the balance of electrostatic interactions. Probably, the action of albumin is carried out due to the restoration and stabilization of the indicated balance of membranes, charactestic of the typical eruthrocyte discoid shape. Restoration of the morphology of cryopreserved erythrocytes before the transfusion can help reduce cell deformation, improve systemic hemodynamics and prevent the development of negative clinical consequences.

The Mechanical Fingerprint of Circulating Tumor Cells (CTCs) in Breast Cancer Patients

Circulating tumor cells (CTCs) are a potential predictive surrogate marker for disease monitoring. Due to the sparse knowledge about their phenotype and its changes during cancer progression and treatment response, CTC isolation remains challenging. Here we focused on the mechanical characterization of circulating non-hematopoietic cells from breast cancer patients to evaluate its utility for CTC detection. For proof of premise, we used healthy peripheral blood mononuclear cells (PBMCs), human MDA-MB 231 breast cancer cells and human HL-60 leukemia cells to create a CTC model system. For translational experiments CD45 negative cells—possible CTCs—were isolated from blood samples of patients with mamma carcinoma. Cells were mechanically characterized in the optical stretcher (OS). Active and passive cell mechanical data were related with physiological descriptors by a random forest (RF) classifier to identify cell type specific properties. Cancer cells were well distinguishable from PBMC in cell line tests. Analysis of clinical samples revealed that in PBMC the elliptic deformation was significantly increased compared to non-hematopoietic cells. Interestingly, non-hematopoietic cells showed significantly higher shape restoration. Based on Kelvin–Voigt modeling, the RF algorithm revealed that elliptic deformation and shape restoration were crucial parameters and that the OS discriminated non-hematopoietic cells from PBMC with an accuracy of 0.69, a sensitivity of 0.74, and specificity of 0.63. The CD45 negative cell population in the blood of breast cancer patients is mechanically distinguishable from healthy PBMC. Together with cell morphology, the mechanical fingerprint might be an appropriate tool for marker-free CTC detection.

Plasmodium falciparum Kelch13 and its artemisinin-resistant mutants assemble as hexamers in solution: a SAXS data driven shape restoration study

Artemisinin-resistant mutations in PfKelch13 identified worldwide are mostly confined to its BTB/POZ and KRP domains. To date, only two crystal structures of the BTB/POZ-KRP domains as tight dimers are available, which limits structure-based interpretations of its functionality. Our solution Small-Angle X-ray Scattering (SAXS) data driven shape restoration of larger length of protein brought forth that: i) PfKelch13 forms a stable hexamer in P6 symmetry, ii) interactions of the N-termini drive the hexameric assembly, and iii) the six KRP domains project independently in space, forming a cauldron-like architecture. While artemisinin-sensitive mutant A578S packed like the wild-type, hexameric assemblies of dominant artemisinin-resistant mutant proteins R539T and C580Y displayed detectable differences in spatial positioning of their BTB/POZ-KRP domains. Lastly, mapping of mutations known to enable artemisinin resistance explained that most mutations exist mainly in these domains because they are non-detrimental to assembly of mutant PfKelch13 and yet can alter the flux of downstream events essential for susceptibility to artemisinin.

Customized polymethylmethacrylate cranioplasty using a low-cost 3-dimensional printed mold

Introduction. Significant cranial defects result from a decompressive craniectomy following head trauma, malignant edema of the brain or intracranial hemorrhage, or resection of tumor affected bone. Unrepaired cranial defects are not just a tremendous esthetical problem. The underlying brain is unprotected, prone to injury, and this state can lead to the so-called ?syndrome of the trephined? with mood instability, headaches, and even a neurological deficit. Currently, there is no widely accepted uniform technique of cranial vault shape restoration. Combining 3D technology with the use of polymethylmethacrylate is a challenging field that can bring good functional and aesthetic results and, in the case of smart design, become efficient, low-cost technology. We offer a possible solution to a problem that would be acceptable in neurosurgical practice. Case outline. We present a 37-year-old male patient with a massive hemicranial defect as a consequence of previous decompressive craniectomy following severe craniocerebral injury. Together with engineers from the appropriate 3D modeling studio, we have designed a two-part mold by laser printing technology using biocompatible advanced polyamide. We made a customized polymethylmethacrylate graft intraoperatively using this mold and achieved good aesthetic results. Conclusion. Reports of 3D printing assisted cranioplasties are growing, describing different techniques and cost- estimation. We hope to introduce a low-cost and simple method for repairing a skull defect.

Direct Displacement Control of Deformed Double Layer Dome

Space structures such as double layer dome is light and active structural system that used for various structural application, for instance structural covers large areas such as exhibition halls, stadium and concert halls. They are aesthetically pleasing in appearance as well as the architectural requirement, in which tolerances of structural shape under changing service conditions are very significant, which high appearance accuracy is requested in some applications. Due to many reasons such as loading, these type of structures may suffer from a noticeable deflection, which leads to a significant potential undesired appearance of the shape. In this situation, the displacements may need to be reduced or eliminated. In this study, by applying the shape adjustment technique that its scheme is depend on the linear force method, shape restoration is performed to the double layer dome model in three different cases corresponding to the directions of loadings were considered. The improvement of controlling nodal displacement can be achieved through using a rather simple and direct method, due to calculating necessary length of actuators by applying a single formulation. It is found that if the number of provided actuators are satisfactory, controlling of all the displaced joints could be performed by a very small percentage of discrepancy, even if the controlled joints connection is not direct with the adjustable members. The technique of shape adjustment is very efficient for double layer dome model, and it can roughly eliminate the displacement of definite joints (Exterior joints only) by simply changing the length of certain bars by eo amount

Direct Displacement Control of Deformed Double Layer Dome

Space structures such as double layer dome is light and active structural system that used for various structural application, for instance structural covers large areas such as exhibition halls, stadium and concert halls. They are aesthetically pleasing in appearance as well as the architectural requirement, in which tolerances of structural shape under changing service conditions are very significant, which high appearance accuracy is requested in some applications. Due to many reasons such as loading, these type of structures may suffer from a noticeable deflection, which leads to a significant potential undesired appearance of the shape. In this situation, the displacements may need to be reduced or eliminated. In this study, by applying the shape adjustment technique that its scheme is depend on the linear force method, shape restoration is performed to the double layer dome model in three different cases corresponding to the directions of loadings were considered. The improvement of controlling nodal displacement can be achieved through using a rather simple and direct method, due to calculating necessary length of actuators by applying a single formulation. It is found that if the number of provided actuators are satisfactory, controlling of all the displaced joints could be performed by a very small percentage of discrepancy, even if the controlled joints connection is not direct with the adjustable members. The technique of shape adjustment is very efficient for double layer dome model, and it can roughly eliminate the displacement of definite joints (Exterior joints only) by simply changing the length of certain bars by eo amount