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Chemistry and Physics of Lipids Jun 2024Chondroitin sulfates (CSs) are important components of the extracellular matrix and side chains of membrane proteoglycans. These polysaccharides are, therefore, likely...
Chondroitin sulfates (CSs) are important components of the extracellular matrix and side chains of membrane proteoglycans. These polysaccharides are, therefore, likely to interact with plasma membranes and play a significant role in modulating cellular functions. So far, the details of the processes occurring at the interface between the extracellular matrix and cellular membranes are not fully understood. In this study, we used experimental methods and atomic-scale molecular dynamics (MD) simulations to reveal the molecular picture of the interactions between CS and phosphocholine (PC) membranes, used as a simplified model of cell membranes. MD simulations reveal that the polysaccharide associates to the PC bilayer as a result of electrostatic interactions between the positively charged quaternary ammonium groups of choline and the negatively charged sulfate groups of CS. Compared to an aqueous medium, the adsorbed polysaccharide chains adopt more elongated conformations, which facilitates the electrostatic interactions with the membrane, and have a high degree of freedom to change their conformations and to adhere to and detach from the membrane surface. Penetrating slightly between the polar groups of the bilayer, they form a loosely anchored layer, but do not intrude into the hydrophobic region of the PC bilayer. The CS adsorption spread the PC headgroups apart, which is manifested by an increase in the value of the area pre lipid. The expansion of the lipid polar groups weakens the dispersion interactions between the lipid acyl chains. As a result, the lipid membrane in the membrane-polysaccharide contact areas becomes more fluid. Our outcomes may help to understand in detail the interaction of chondroitin sulfate with zwitterionic membranes at the molecular level, which is of biological interest since many biological processes depend on lipid-CS interactions.
PubMed: 38950675
DOI: 10.1016/j.chemphyslip.2024.105417 -
Ophthalmology. Retina Jun 2024To describe the retinal and vitreous changes in eyes showing myopic macular schisis (MMS) improvement when vitrectomy was not performed and identify triggering factors.
PURPOSE
To describe the retinal and vitreous changes in eyes showing myopic macular schisis (MMS) improvement when vitrectomy was not performed and identify triggering factors.
DESIGN
Retrospective observational study.
SUBJECTS
Patients with non-operated myopic macular schisis METHODS: The records of patients with MMS who were followed without performing surgery for more than 6 months were retrospectively reviewed, and the eyes showing an anatomical improvement were included. MMS evolution was analyzed quantitatively (central foveal thickness [CFT], parafoveal thickness, maximum height) and qualitatively (presence/absence of foveal detachment, lamellar hole, epiretinal membrane, choroidal neovascularization, inner and outer retinoschisis, vitreous status) at baseline and at the final visit. An anatomical improvement was defined as a decrease in CFT by at least 50 μm.
MAIN OUTCOME MEASURE
The rate anatomical improvement of MMS without performing vitrectomy and the morphological changes observed in these cases.
RESULTS
In a cohort of 74 non-operated eyes with MMS, MMS improved in 14 eyes (19%) after a mean follow-up of 55 ± 38 months (range: 8-138). In these improved cases, the mean decrease in CFT was 153 ± 166 μm (range: 24-635, p=0.005) and a complete resolution of MMS was observed in 9 eyes (64%). In 9 eyes (64%), the improvement was associated with visible vitreous changes in the macular area on the OCT scans. The mean visual acuity, which was already good at baseline (20/50, 0.4 ± 0.2 LogMAR), increased at the last visit (20/40, 0.3 ± 0.3 LogMAR) but without reaching significance.
CONCLUSION
This long-term follow-up analysis showed that almost 20% of MMS in eyes without indication for surgery could improve over time. In most cases, the improvement was associated with an apparent resolution of vitreous tensions.
PubMed: 38950656
DOI: 10.1016/j.oret.2024.06.017 -
Methods in Molecular Biology (Clifton,... 2024In vitro biofilm models have allowed researchers to investigate the role biofilms play in the pathogenesis, virulence, and antimicrobial drug susceptibility of a wide...
In vitro biofilm models have allowed researchers to investigate the role biofilms play in the pathogenesis, virulence, and antimicrobial drug susceptibility of a wide range of bacterial pathogens. Rotary cell culture systems create three-dimensional cellular structures, primarily applied to eukaryotic organoids, that better capture characteristics of the cells in vivo. Here, we describe how to apply a low-shear, detergent-free rotary cell culture system to generate biofilms of Mycobacterium bovis BCG. The three-dimensional biofilm model forms mycobacterial cell aggregates in suspension as surface-detached biomass, without severe nutrient starvation or environmental stress, that can be harvested for downstream experiments. Mycobacterium bovis BCG derived from cell clusters display antimicrobial drug tolerance, presence of an extracellular matrix, and evidence of cell wall remodeling, all features of biofilm-associated bacteria that may be relevant to the treatment of tuberculosis.
Topics: Biofilms; Mycobacterium bovis; Cell Culture Techniques; Cell Culture Techniques, Three Dimensional
PubMed: 38949696
DOI: 10.1007/978-1-0716-3981-8_2 -
Mikrochimica Acta Jun 2024A novel scaffold for in situ electrochemical detection of cell biomarkers was developed using electrospun nanofibers and commercial adhesive polymeric membranes. The...
A novel scaffold for in situ electrochemical detection of cell biomarkers was developed using electrospun nanofibers and commercial adhesive polymeric membranes. The electrochemical sensing of cell biomarkers requires the cultivation of the cells on/near the (bio)sensor surface in a manner to preserve an appropriate electroactive available surface and to avoid the surface passivation and sensor damage. This can be achieved by employing biocompatible nanofiber meshes that allow the cells to have a normal behavior and do not alter the electrochemical detection. For a better mechanical stability and ease of handling, nylon 6/6 nanofibers were collected on commercial polymeric membranes, at an optimal fiber density, obtaining a double-layered platform. To demonstrate the functionality of the fabricated scaffold, the screening of cellular stress has been achieved integrating melanoma B16-F10 cells and the (bio)sensor components on the transducer whereas the melanin exocytosis was successfully quantified using a commercial electrode. Either directly on the surface of the (bio)sensor or spatially detached from it, the integration of cell cultures in biosensing platforms based on electrospun nanofibers represents a powerful bioanalytical tool able to provide real-time information about the biomarker release, enzyme activity or inhibition, and monitoring of various cellular events.
Topics: Nanofibers; Animals; Mice; Electrochemical Techniques; Biosensing Techniques; Cell Line, Tumor; Melanins; Biomarkers; Tissue Scaffolds; Exocytosis; Melanoma, Experimental
PubMed: 38949689
DOI: 10.1007/s00604-024-06523-w -
Logopedics, Phoniatrics, Vocology Jul 2024This study aims to extend current knowledge about the possibilities and challenges encountered by Swedish speech and language pathologists (SLPs) in targeting everyday...
Swedish speech and language pathologists reflect on how their clinical practises align to everyday language and communication skills of children with developmental language disorder.
This study aims to extend current knowledge about the possibilities and challenges encountered by Swedish speech and language pathologists (SLPs) in targeting everyday language and communication in children with developmental language disorder (DLD). To explore this matter, unstructured focus groups were conducted where 15 SLPs, working with children with DLD, shared their views on the alignment between their clinical practices and children's everyday lives. Thematic analysis was used to analyse the data, which resulted in five themes: ; ; ; , and . The SLPs stressed the importance of targeting everyday skills and needs, but they experienced themselves as being detached from the children's daily context. Collaboration with caregivers and (pre)school staff was emphasised; however, the resources and capacity of the caregivers and staff varied, and this was experienced as a challenge for providing the most appropriate care. Some children and their families were situated in a multifaceted context and needed more extensive care, and this group was described as increasing. However, the services that the SLPs were able to offer varied and were largely regulated by organisational constraints. Individualised services are crucial for ensuring a positive development for children with DLD and for empowering caregivers to be effective collaborative partners in intervention. Therefore, it is essential for SLPs to have the time and resources to ensure high-quality care.
PubMed: 38949090
DOI: 10.1080/14015439.2024.2371284 -
Lab on a Chip Jul 2024Microfluidic chips have emerged as significant tools in cell culture due to their capacity for supporting cells to adopt more physiologically relevant morphologies in 3D...
Microfluidic chips have emerged as significant tools in cell culture due to their capacity for supporting cells to adopt more physiologically relevant morphologies in 3D compared with traditional cell culture in 2D. Currently, irreversible bonding methods, where chips cannot be detached from their substrates without destroying the structure, are commonly used in fabrication, making it challenging to conduct further analysis on cells that have been cultured on-chip. Although some reversible bonding techniques have been developed, they are either restricted to certain materials such as glass, or require complex processing procedures. Here, we demonstrate a simple and reversible polydimethylsiloxane (PDMS)-polystyrene (PS) bonding technique that allows devices to withstand extended operations while pressurized, and supports long-term stable cell cultures. More importantly, it allows rapid and gentle live cell extraction for downstream manipulation and characterization after long-term on-chip culturing, and even further subculturing. Our new approach could greatly facilitate microfluidic chip-based cell and tissue cultures, overcoming current analytical limitations and opening up new avenues for downstream uses of on-chip cultures, including 3D-engineered tissue structures for biomedical applications.
PubMed: 38949063
DOI: 10.1039/d3lc01019h -
BioRxiv : the Preprint Server For... Jun 2024The distal bronchioles in Idiopathic Pulmonary Fibrosis (IPF) exhibit histopathological abnormalities such as bronchiolization, peribronchiolar fibrosis and honeycomb...
UNLABELLED
The distal bronchioles in Idiopathic Pulmonary Fibrosis (IPF) exhibit histopathological abnormalities such as bronchiolization, peribronchiolar fibrosis and honeycomb cysts that contribute to the overall architectural remodeling of lung tissue seen in the disease. Here we describe an additional histopathologic finding of epithelial desquamation in patients with IPF, wherein epithelial cells detach from the basement membrane of the distal bronchioles. To understand the mechanism driving this pathology, we performed spatial transcriptomics of the epithelial cells and spatial proteomics of the basement membrane of the distal bronchioles from IPF patients and patients with no prior history of lung disease. Our findings reveal a downregulation of cell junctional components, upregulation of epithelial-mesenchymal transition signatures and dysregulated basement membrane matrix in IPF distal bronchioles, facilitating epithelial desquamation. Further, functional assays identified regulation between Collagen IV in the matrix, and the junctional genes and , that is crucial for maintaining distal bronchiolar homeostasis. In IPF, this balanced regulation between matrix and cell-junctions is disrupted, leading to loss of epithelial adhesion, peribronchiolar fibrosis and epithelial desquamation. Overall, our study suggests that in IPF the interplay between the loss of cell junctions and a dysregulated matrix results in desquamation of distal bronchiolar epithelium and lung remodeling, exacerbating the disease.
ONE SENTENCE SUMMARY
Two-way regulation of cell junctional proteins and matrix proteins drives cellular desquamation and fibrosis in the distal bronchioles of patients with Idiopathic Pulmonary Fibrosis.
PubMed: 38948715
DOI: 10.1101/2024.06.17.599411 -
BioRxiv : the Preprint Server For... Jun 2024Hairpin forming expanded CAG/CTG repeats pose significant challenges to DNA replication which can lead to replication fork collapse. Long CAG/CTG repeat tracts relocate...
UNLABELLED
Hairpin forming expanded CAG/CTG repeats pose significant challenges to DNA replication which can lead to replication fork collapse. Long CAG/CTG repeat tracts relocate to the nuclear pore complex to maintain their integrity. Forks impeded by DNA structures are known to activate the DNA damage checkpoint, thus we asked whether checkpoint proteins play a role in relocation of collapsed forks to the nuclear periphery in . We show that relocation of a (CAG/CTG) tract is dependent on activation of the Mrc1/Rad53 replication checkpoint. Further, checkpoint-mediated phosphorylation of the kinetochore protein Cep3 is required for relocation, implicating detachment of the centromere from the spindle pole body. Activation of this pathway leads to DNA damage-induced microtubule recruitment to the repeat. These data suggest a role for the DNA replication checkpoint in facilitating movement of collapsed replication forks to the nuclear periphery by centromere release and microtubule-directed motion.
HIGHLIGHTS
The DNA damage checkpoint is needed for relocation of a structure-forming CAG repeat tract to the nuclear pore complexThe importance of Mrc1 (hClaspin) implicates fork uncoupling as the initial checkpoint signalPhosphorylation of the Cep3 kinetochore protein by Dun1 kinase modulates centromere release, which is critical for collapsed fork repositioningDamage-inducible nuclear microtubules colocalize with the CAG repeat locus and are required for relocalizationEstablishes a new role for the DNA replication and DNA damage checkpoint response to trigger repositioning of collapsed forks within the nucleus.
PubMed: 38948692
DOI: 10.1101/2024.06.17.599319 -
Bio-protocol Jun 2024All aerial organs in plants originate from the shoot apical meristem, a specialized tissue at the tip of a plant, enclosing a few stem cells. Understanding developmental...
All aerial organs in plants originate from the shoot apical meristem, a specialized tissue at the tip of a plant, enclosing a few stem cells. Understanding developmental dynamics within this tissue in relation to internal and external stimuli is of crucial importance. Imaging the meristem at the cellular level beyond very early stages requires the apex to be detached from the plant body, a procedure that does not allow studies in living, intact plants over longer periods. This protocol describes a new confocal microscopy method with the potential to image the shoot apical meristem of an intact, soil-grown, flowering Arabidopsis plant over several days. The setup opens new avenues to study apical stem cells, their interconnection with the whole plant, and their responses to environmental stimuli. Key features • Novel dissection and imaging method of the shoot apical meristem of . • Procedure performed with intact, soil-grown, flowering plants. • Possibility of long-term live imaging of the shoot apical meristem. • Protocol can be adapted to different plant species.
PubMed: 38948259
DOI: 10.21769/BioProtoc.5015 -
Trauma Case Reports Aug 2024Thumb distal amputation refers to the loss of a portion of the thumb at or near the tip, which can be caused by various injuries such as crush injuries, lacerations, or...
Thumb distal amputation refers to the loss of a portion of the thumb at or near the tip, which can be caused by various injuries such as crush injuries, lacerations, or avulsions. Several surgical methods can be used to repair thumb distal amputations, including composite graft, flap reconstruction, replantation, and amputation revision. In this case report, we describe a successful surgical procedure performed on three healthy men (19, 26, and 44 years old) who suffered a sharp amputation of their left and right hands thumb. In one case initial fixation of the amputated part was performed by a general orthopedic surgeon as a composite graft, two other cases were referred us without any procedure. The procedure involved irrigation and minimal debridement and deepithelializing the amputated part and fixation it with one or two 1.5 mm steinman pins and repairing the nail bed with7/0 absorbable sutures. An adiposofaciocutaneous flap from the index finger was used to cover the pulp of the thumb and the nail bed, while a full-thickness grafts from the same wrist in one case and medial part of ipsilateral arm in others were used to repair the defect on the dorsal side of the index finger. The wound was dressed, and the sutures were removed after two weeks. The base of the flap was detached from the index finger after three weeks, and the kwires were removed after six weeks. The flap and graft were successfully taken, except for a small part of the tip of the thumb. Two years after the operation, in two patients and 3 months in whom was operated recently, all the patient's thumbs had a reasonable shape and length with minimal nail deformity. The use of an index finger based adiposofaciocutaneous flap and full-thickness graft in these cases allowed for successful reconstruction of the thumb and, improving both function and appearance.
PubMed: 38948102
DOI: 10.1016/j.tcr.2024.101052