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Physics in Medicine and Biology Nov 2012An investigation into the effect of clinical ultrasound exposure on adherent microbubbles is described. A flow phantom was constructed in which targeted microbubbles...
An investigation into the effect of clinical ultrasound exposure on adherent microbubbles is described. A flow phantom was constructed in which targeted microbubbles were attached using biotin-streptavidin linkages. Microbubbles were insonated by broadband imaging pulses (centred at 2.25 MHz) over a range of pressures (peak negative pressure (PNP) = 60-375 kPa). Individual adherent bubbles were observed optically and classified as either being isolated or with a single neighbouring bubble. It is found that bubble detachment and deflation are two significant effects, even during low amplitude ultrasound exposure. Specifically, while at very low acoustic pressure (PNP < 75 kPa) 95% of the bubbles were not affected, at medium pressure (151 kPa < P < 225 kPa) 53% of the bubbles detached and at higher pressures (301 kPa < P < 375 kPa) 96% of the bubbles detached. In addition, more than 50% of the bubbles underwent deflation at pressures between 301 and 375 kPa. At pressures between 226 and 300 kPa, more adherent bubbles detached when there was a neighbouring bubble, suggesting the role of multiple scattering and secondary Bjerknes force on bubble detachment. The flow shear, primary and secondary Bjerknes forces exerted on each bubble were calculated and compared to the estimated forces acting on the bubble due to oscillations. The oscillation force is shown to be much higher than other forces. The mechanisms of bubble detachment are discussed.
Topics: Adhesives; Biotin; Contrast Media; Microbubbles; Microscopy; Models, Theoretical; Streptavidin; Ultrasonics
PubMed: 23044731
DOI: 10.1088/0031-9155/57/21/6999 -
Microbiological Research Jun 2021RpoN (δ54) as a global regulator controls crucialvirulence-associated phenotype, which can regulate flagellum and exopolysaccharides (EPS) during pathogenic biofilm...
RpoN (δ54) as a global regulator controls crucialvirulence-associated phenotype, which can regulate flagellum and exopolysaccharides (EPS) during pathogenic biofilm formation. However, the knowledge of the roles of rpoN in biofilm formation of V. alginolyticus is limited, especially at different cell densities. Herein, deletion mutant strain ΔrpoN, complementary strain ΔrpoN-C and negative control strain ΔrpoN-Z were constructed to investigate the effects of rpoN on biofilm formation of V. alginolyticus HN08155 based on flagellum and EPS at different cell density conditions. The results showed that all of strains can form biofilm, and biofilms of strains with rpoN were formed at low cell density (LCD) and detached at high cell density (HCD), while those of ΔrpoN and ΔrpoN-Z were absent at LCD and accumulated excessively with a spotty pellicle at HCD without detaching. The EPS contents of strains with rpoN was greater than that of ΔrpoN and ΔrpoN-Z at LCD, while the opposite trends were observed at HCD. The expression levels of rpoN were quantified, which were consistent with the trend of biofilm formation. It's worth noting that absence of rpoN resulted in the failure of biofilm detachment, lacking of flagellum and decreasing motility, indicating that rpoN was not necessary for biofilm formation, but it was essential for biofilm detachment.
Topics: Bacterial Proteins; Biofilms; Cell Count; Flagella; Gene Expression Regulation, Bacterial; Phenotype; Polysaccharides; RNA Polymerase Sigma 54; Vibrio alginolyticus
PubMed: 33684638
DOI: 10.1016/j.micres.2021.126728 -
Clinical Ophthalmology (Auckland, N.Z.) 2023Encircling (360 degree) retinal detachment prophylaxis using indirect ophthalmoscope laser delivery recently achieved strong proof of safety and effectiveness by...
Encircling (360 degree) retinal detachment prophylaxis using indirect ophthalmoscope laser delivery recently achieved strong proof of safety and effectiveness by preventing the development of peripheral retinal tears and detachments in the eyes of patients with Stickler syndrome (syndromic eyes). Untreated, Stickler syndrome patients have a 65% lifetime risk of retinal detachment (half by age 20, 80% bilateral). This report describes an optimal technique of encircling laser retinopexy to also prevent the more common retinal detachments seen in aging (non-syndromic) eyes that share with Stickler syndrome the common pathogenesis of peripheral retinal tears caused by vitreous traction.
PubMed: 37273500
DOI: 10.2147/OPTH.S406337 -
Medicine Jun 2023The Descemet layer is a dense layer of tissue that does not detach under normal circumstances. Descemet layer detachment may occur after intraocular surgery, but the...
RATIONALE
The Descemet layer is a dense layer of tissue that does not detach under normal circumstances. Descemet layer detachment may occur after intraocular surgery, but the Descemet layer spontaneously detached after trauma in this child, which is relatively rare. After looking for the cause, we found that the child was diagnosed with congenital glaucoma, and the trauma induced the Descemet's membrane detachment.
PATIENT CONCERNS
The parents of the patient expected the child to recover the normal shape of the cornea as soon as possible, improve vision, and solve the problem of congenital glaucoma.
DIAGNOSES
The patient was diagnosed with Descemet's membrane detachment of the left eye and congenital glaucoma in both eyes.
INTERVENTIONS
During operation, inflation gas is injected into the anterior chamber, the Descemet's membrane is reset, and glaucoma surgery is performed.
OUTCOMES
The Descemet's membrane in the child's eye was reset, and after glaucoma surgery, the intraocular pressure of the child was normal.
LESSONS
The analysis of the disease is not only to solve the problems seen but also to deeply analyze the internal causes and pathological changes in combination with the symptoms and signs, so as to discover the essence of the problem and solve the fundamental problem of the patient.
Topics: Child; Humans; Descemet Membrane; Insufflation; Anterior Chamber; Research; Glaucoma; Corneal Diseases
PubMed: 37352059
DOI: 10.1097/MD.0000000000034121 -
Translational Vision Science &... Aug 2020We developed a method to automatically locate and quantify graft detachment after Descemet's membrane endothelial keratoplasty (DMEK) in anterior segment optical...
PURPOSE
We developed a method to automatically locate and quantify graft detachment after Descemet's membrane endothelial keratoplasty (DMEK) in anterior segment optical coherence tomography (AS-OCT) scans.
METHODS
A total of 1280 AS-OCT B-scans were annotated by a DMEK expert. Using the annotations, a deep learning pipeline was developed to localize scleral spur, center the AS-OCT B-scans and segment the detached graft sections. Detachment segmentation model performance was evaluated per B-scan by comparing (1) length of detachment and (2) horizontal projection of the detached sections with the expert annotations. Horizontal projections were used to construct graft detachment maps. All final evaluations were done on a test set that was set apart during training of the models. A second DMEK expert annotated the test set to determine interrater performance.
RESULTS
Mean scleral spur localization error was 0.155 mm, whereas the interrater difference was 0.090 mm. The estimated graft detachment lengths were in 69% of the cases within a 10-pixel (∼150 µm) difference from the ground truth (77% for the second DMEK expert). Dice scores for the horizontal projections of all B-scans with detachments were 0.896 and 0.880 for our model and the second DMEK expert, respectively.
CONCLUSIONS
Our deep learning model can be used to automatically and instantly localize graft detachment in AS-OCT B-scans. Horizontal detachment projections can be determined with the same accuracy as a human DMEK expert, allowing for the construction of accurate graft detachment maps.
TRANSLATIONAL RELEVANCE
Automated localization and quantification of graft detachment can support DMEK research and standardize clinical decision-making.
Topics: Descemet Membrane; Descemet Stripping Endothelial Keratoplasty; Endothelium, Corneal; Humans; Neural Networks, Computer; Tomography, Optical Coherence
PubMed: 32884855
DOI: 10.1167/tvst.9.2.48 -
The British Journal of Ophthalmology Oct 1985A study of 132 cases of aphakic retinal detachment (ARD) following mainly intracapsular cataract surgery has been made. Forty-nine cases (37%) were found to have...
A study of 132 cases of aphakic retinal detachment (ARD) following mainly intracapsular cataract surgery has been made. Forty-nine cases (37%) were found to have vitreous incarcerated into the cataract section out of a total of 54 (41%) cases who had suffered a vitreous complication during cataract surgery. A study of the characteristics of ARD reveals that those cases having had a vitreous complication in the management of their cataracts are more likely to develop detachment within three months than those not suffering from such a complication. The occurrence of these early post-extraction retinal detachments is not influenced by the presence of underlying axial myopia. When we compared ARD in patients whose cataract extractions had been complicated by vitreous incarceration with those ARDs following uncomplicated cataract surgery, we found that the characteristics of the detachments were very similar. Thus distribution of underlying myopia, extent of detachment, length of time of detachment, and multiplicity and type of retinal holes were generally similar. However, ARD following complicated cataract surgery is more likely to suffer from periretinal fibrosis. The findings confirmed the risk of ARD following complicated intracapsular cataract surgery and support the tendency to perform the extracapsular operation.
Topics: Aged; Cataract Extraction; Female; Humans; Intraoperative Complications; Male; Middle Aged; Myopia; Postoperative Complications; Retinal Detachment; Retinal Perforations; Time Factors; Vitreous Body
PubMed: 4052358
DOI: 10.1136/bjo.69.10.737 -
The Journal of General Physiology Jan 2019After muscle contraction, myosin cross-bridge heads detach from thin actin filaments during relaxation. Structural and kinetic data of cross-bridge-thin filament...
After muscle contraction, myosin cross-bridge heads detach from thin actin filaments during relaxation. Structural and kinetic data of cross-bridge-thin filament interactions have shown that tropomyosin's position on F-actin is biased toward the blocked or closed states when myosin detaches. It is not clear if structural linkages between tropomyosin and myosin cross-bridge heads, or tropomyosin and Ca-free troponin, drive the process or whether tropomyosin movement is energetically independent of myosin and troponin influence. Here we provide in silico data about tropomyosin dynamics on troponin/myosin-free F-actin indicating that tropomyosin moves from the open state toward blocked- or closed-state positions on actin. To follow transitions inherent to tropomyosin itself on F-actin, we performed MD simulations initiated from the blocked-, open-, and intermediate-state models and followed tropomyosin over the surface of F-actin in the absence of myosin and troponin. These MD simulations maintain tropomyosin in a cable-like conformation, including the tropomyosin overlap domain, while allowing tropomyosin to retain most of its motional freedom. Tropomyosin shows considerable azimuthal movement away from the open state toward the surrounds of a more energetically favorable blocked B-state position over F-actin. In contrast, little movement away from the B-state location is observed. Our results are consistent with previous predictions based on electrostatic interaction energy landscapes determined by rigid-body translocation of tropomyosin. They support the view that in the absence of myosin, i.e., when myosin cross-bridges detach from actin, the blocked- or closed-state positions of tropomyosin are energetically favored, while the open state is not.
Topics: Actin Cytoskeleton; Actins; Calcium; Models, Molecular; Motion; Movement; Muscle Contraction; Muscle, Skeletal; Myosins; Protein Binding; Static Electricity; Tropomyosin; Troponin
PubMed: 30442774
DOI: 10.1085/jgp.201812188 -
Metabolites Mar 2022Tumor cells detached from the extracellular matrix (ECM) undergo anoikis resistance and metabolic reprogramming to facilitate cancer cell survival and promote...
Tumor cells detached from the extracellular matrix (ECM) undergo anoikis resistance and metabolic reprogramming to facilitate cancer cell survival and promote metastasis. During ECM detachment, cancer cells utilize genomic methylation to regulate transcriptional events. One-carbon (1C) metabolism is a well-known contributor of SAM, a global substrate for methylation reactions, especially DNA methylation. DNA methylation-mediated repression of NK cell ligands MICA and MICB during ECM detachment has been overlooked. In the current work, we quantitated the impact of ECM detachment on one-carbon metabolites, expression of 1C regulatory pathway genes, and total methylation levels. Our results showed that ECM detachment promotes the accumulation of one-carbon metabolites and induces regulatory pathway genes and total DNA methylation. Furthermore, we measured the expression of well-known targets of DNA methylation in NK cell ligands in cancer cells, namely, MICA/B, during ECM detachment and observed low expression compared to ECM-attached cancer cells. Finally, we treated the ECM-detached cancer cells with vitamin C (a global methylation inhibitor) and observed a reduction in the promoter methylation of NK cell ligands, resulting in MICA/B re-expression. Treatment with vitamin C was also found to reduce global DNA methylation levels in ECM-detached cancer cells.
PubMed: 35323710
DOI: 10.3390/metabo12030267 -
PloS One 2018To report on the rate and timing of retinal reattachment and outcomes for retinoblastoma children who have total retinal detachments at presentation to our center and...
PURPOSE
To report on the rate and timing of retinal reattachment and outcomes for retinoblastoma children who have total retinal detachments at presentation to our center and were treated with intra-arterial chemotherapy (ophthalmic artery chemosurgery, OAC).
PATIENTS AND METHODS
Single-center retrospective review of retinoblastoma patients who presented with total retinal detachments and were subsequently treated with OAC at MSKCC between May 2006 and July 2016. Endpoints were retinal detachment resolution, visual function, ERG amplitude, ocular survival, and patient survival from metastases.
RESULTS
87 eyes of 84 retinoblastoma patients were included. Using a survival multistate model, by 36 months of follow-up, there was a 54% cumulative probability of complete retinal reattachment and a 76% probability of partial reattachment. 24% of eyes that completely reattached received only OAC without any prior or adjuvant treatments. Eyes that completely reattached were significantly more likely to have been diagnosed at a younger age (p<0.0001) and to have greater initial ERG values (p = 0.006). At final follow-up, 14% of eyes had gained at least 25 μV of ERG activity, and 8.0% had achieved hand motion vision or better, including one to 20/60. 13% of eyes were enucleated. No patient died from metastatic disease, and only one developed metastases.
CONCLUSION
OAC can successfully treat previously considered "non-salvageable" retinoblastoma eyes with total retinal detachments, promote retinal reattachment in the majority of eyes, and preserve ocular and patient survival.
Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Carboplatin; Child, Preschool; Electroretinography; Female; Follow-Up Studies; Humans; Infant; Infusions, Intra-Arterial; Male; Melphalan; Ophthalmic Artery; Retina; Retinal Detachment; Retinal Neoplasms; Retinoblastoma; Retrospective Studies; Survival Analysis; Topotecan; Treatment Outcome
PubMed: 29698399
DOI: 10.1371/journal.pone.0195395 -
ACS Omega Feb 2022Water sensitivity (WS) and salinity sensitivity (SS) are key issues to be investigated for instructing coalbed methane (CBM) production. This work studied the influences...
Water sensitivity (WS) and salinity sensitivity (SS) are key issues to be investigated for instructing coalbed methane (CBM) production. This work studied the influences of minerals and pores on WS and SS of medium-volatile bituminous coal (MVBC) and highly volatile bituminous coal (HVBC) deposited in northwestern China by detecting and observing minerals using the TESCAN Integrated Mineral Analyzer, simulating WS and SS, and characterizing pore structural complexities using rate-controlled mercury penetration. The results show that (1) kaolinite is mainly distributed as irregular particles or fragile aggregates attaching on the bedding surface or filling in meso-pores or transition pores, showing a high potential for detachment; (2) MVBC and HVBC in this study are characterized as medium to weak WS and weak SS, respectively; (3) for HVBC during the WS or SS process, kaolinite distributed in meso-pores or transition pores first detaches and then migrates to the narrow throat of macro-pores and super macro-pores, leading to volume decreases of macro-pores and super macro-pores and loss of permeability; and (4) kaolinite filling in macro-pores of MVBC detaches, then migrates, and finally deposits in super macro-pores after WS and SS, leading to losses of super macro-pore volume and permeability. Results of this study can enhance the scientific knowledge on WS and SS of coal during CBM development.
PubMed: 35128260
DOI: 10.1021/acsomega.1c05995