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Journal of Visualized Experiments : JoVE May 2024Hemostasis, the process of normal physiological control of vascular damage, is fundamental to human life. We all suffer minor cuts and puncture wounds from time to time....
Hemostasis, the process of normal physiological control of vascular damage, is fundamental to human life. We all suffer minor cuts and puncture wounds from time to time. In hemostasis, self-limiting platelet aggregation leads to the formation of a structured thrombus in which bleeding cessation comes from capping the hole from the outside. Detailed characterization of this structure could lead to distinctions between hemostasis and thrombosis, a case of excessive platelet aggregation leading to occlusive clotting. An imaging-based approach to puncture wound thrombus structure is presented here that draws upon the ability of thin-section electron microscopy to visualize the interior of hemostatic thrombi. The most basic step in any imaging-based experimental protocol is good sample preparation. The protocol provides detailed procedures for preparing puncture wounds and platelet-rich thrombi in mice for subsequent electron microscopy. A detailed procedure is given for in situ fixation of the forming puncture wound thrombus and its subsequent processing for staining and embedding for electron microscopy. Electron microscopy is presented as the end imaging technique because of its ability, when combined with sequential sectioning, to visualize the details of the thrombus interior at high resolution. As an imaging method, electron microscopy gives unbiased sampling and an experimental output that scales from nanometer to millimeters in 2 or 3 dimensions. Appropriate freeware electron microscopy software is cited that will support wide-area electron microscopy in which hundreds of frames can be blended to give nanometer-scale imaging of entire puncture wound thrombi cross-sections. Hence, any subregion of the image file can be placed easily into the context of the full cross-section.
Topics: Animals; Mice; Microscopy, Electron; Thrombosis; Hemostasis; Punctures
PubMed: 38856226
DOI: 10.3791/66479 -
Journal of Visualized Experiments : JoVE May 2024Volume electron microscopy (Volume EM) has emerged as a powerful tool for visualizing the 3D structure of cells and tissues with nanometer-level precision. Within the...
Volume electron microscopy (Volume EM) has emerged as a powerful tool for visualizing the 3D structure of cells and tissues with nanometer-level precision. Within the retina, various types of neurons establish synaptic connections in the inner and outer plexiform layers. While conventional EM techniques have yielded valuable insights into retinal subcellular organelles, their limitation lies in providing 2D image data, which can hinder accurate measurements. For instance, quantifying the size of three distinct synaptic vesicle pools, crucial for synaptic transmission, is challenging in 2D. Volume EM offers a solution by providing large-scale, high-resolution 3D data. It is worth noting that sample preparation is a critical step in Volume EM, significantly impacting image clarity and contrast. In this context, we outline a sample preparation protocol for the 3D reconstruction of photoreceptor axon terminals in the retina. This protocol includes three key steps: retina dissection and fixation, sample embedding processes, and selection of the area of interest.
Topics: Retina; Animals; Microscopy, Electron; Imaging, Three-Dimensional; Mice; Volume Electron Microscopy
PubMed: 38856213
DOI: 10.3791/66589 -
Journal of Visualized Experiments : JoVE May 2024[Ga]Ga-FAPI-46 is a promising new tracer for the imaging of fibroblast activation protein (FAP) by positron emission tomography (PET). Labeled FAP inhibitors (FAPIs)...
[Ga]Ga-FAPI-46 is a promising new tracer for the imaging of fibroblast activation protein (FAP) by positron emission tomography (PET). Labeled FAP inhibitors (FAPIs) have demonstrated uptake in various types of cancers, including breast, lung, prostate, pancreatic and colorectal cancer. FAPI-PET also possesses a practical advantage over FDG-PET as fasting and resting are not required. [Ga]Ga-FAPI-46 exhibits enhanced pharmacokinetic properties, improved tumor retention, and higher contrast images than the earlier presented [Ga]Ga-FAPI-02 and [Ga]Ga-FAPI-04. Although a manual synthesis protocol for [Ga]Ga-FAPI-46 was initially described, in recent years, automated methods using different commercial synthesizers have been reported. In this work, we describe the development of the automated synthesis of [Ga]Ga-FAPI-46 using the iPHASE MultiSyn synthesizer for clinical applications. Initially, optimization of the reaction time and comparison of the performance of four different solid phase extraction (SPE) cartridges for final product purification were investigated. Then, the development and validation of the production of 0.6-1.7 GBq of [Ga]Ga-FAPI-46 were conducted using these optimized parameters. The product was synthesized in 89.8 ± 4.8% decay corrected yield (n = 6) over 25 min. The final product met all recommended quality control specifications and was stable up to 3 h post synthesis.
Topics: Gallium Radioisotopes; Radiopharmaceuticals; Humans; Positron-Emission Tomography; Membrane Proteins; Endopeptidases
PubMed: 38856210
DOI: 10.3791/66708 -
Journal of Immunological Methods Jun 2024Flagellum-mediated motility is essential to Pseudomonas aeruginosa (P. aeruginosa) virulence. Antibody against flagellin reduces motility and inhibits the spread of the...
Flagellum-mediated motility is essential to Pseudomonas aeruginosa (P. aeruginosa) virulence. Antibody against flagellin reduces motility and inhibits the spread of the bacteria from the infection site. The standard soft-agar assay to demonstrate anti-flagella motility inhibition requires long incubation times, is difficult to interpret, and requires large amounts of antibody. We have developed a time-lapse video microscopy method to analyze anti-flagellin P. aeruginosa motility inhibition that has several advantages over the soft agar assay. Antisera from mice immunized with flagellin type A or B were incubated with Green Fluorescent Protein (GFP)-expressing P. aeruginosa strain PAO1 (FlaB+) and GFP-expressing P. aeruginosa strain PAK (FlaA+). We analyzed the motion of the bacteria in video taken in ten second time intervals. An easily measurable decrease in bacterial locomotion was observed microscopically within minutes after the addition of small volumes of flagellin antiserum. From data analysis, we were able to quantify the efficacy of anti-flagellin antibodies in the test serum that decreased P. aeruginosa motility. This new video microscopy method to assess functional activity of anti-flagellin antibodies required less serum, less time, and had more robust and reproducible endpoints than the standard soft agar motility inhibition assay.
PubMed: 38852836
DOI: 10.1016/j.jim.2024.113701 -
Communications Biology Jun 2024The Drosophila model is pivotal in deciphering the pathophysiological underpinnings of various human ailments, notably aging and cardiovascular diseases. Cutting-edge...
The Drosophila model is pivotal in deciphering the pathophysiological underpinnings of various human ailments, notably aging and cardiovascular diseases. Cutting-edge imaging techniques and physiology yield vast high-resolution videos, demanding advanced analysis methods. Our platform leverages deep learning to segment optical microscopy images of Drosophila hearts, enabling the quantification of cardiac parameters in aging and dilated cardiomyopathy (DCM). Validation using experimental datasets confirms the efficacy of our aging model. We employ two innovative approaches deep-learning video classification and machine-learning based on cardiac parameters to predict fly aging, achieving accuracies of 83.3% (AUC 0.90) and 79.1%, (AUC 0.87) respectively. Moreover, we extend our deep-learning methodology to assess cardiac dysfunction associated with the knock-down of oxoglutarate dehydrogenase (OGDH), revealing its potential in studying DCM. This versatile approach promises accelerated cardiac assays for modeling various human diseases in Drosophila and holds promise for application in animal and human cardiac physiology under diverse conditions.
Topics: Animals; Cardiomyopathy, Dilated; Aging; Disease Models, Animal; Machine Learning; Drosophila melanogaster; Deep Learning; Heart; Humans; Drosophila
PubMed: 38849449
DOI: 10.1038/s42003-024-06371-7 -
Translational Pediatrics May 2024The goal of fluid resuscitation and the use of inotropes in septic shock has traditionally focused on improving blood pressure and cardiac output, without considering...
BACKGROUND
The goal of fluid resuscitation and the use of inotropes in septic shock has traditionally focused on improving blood pressure and cardiac output, without considering the microcirculatory changes. Reaching macrocirculatory goals but with persistent microcirculatory abnormalities (hemodynamic incoherence) in septic shock has been associated with greater organ dysfunction and mortality. The objective of this study was to evaluate the microcirculation (flow and capillary density) and endothelial glycocalyx changes associated with the use of milrinone in children with septic shock, as well as their relationship with clinical variables and organ dysfunction.
METHODS
A prospective cohort study from February 2022 to January 2023 at a university hospital (Fundación Cardioinfantil-Instituto de Cardiología). Sublingual video microscopy was used to evaluate capillary density, microvascular flow rates and perfused boundary region (PBR-inverse parameter of glycocalyx thickness-abnormal if >2.0 microns). The primary outcome was the association between microcirculation and endothelial glycocalyx changes related to the use of milrinone.
RESULTS
A total of 140 children with a median age of two years [interquartile range (IQR) 0.58-12.1] were included. About 57.9% (81/140) of the patients received milrinone infusions. Twenty-four hours after receiving milrinone, the patients maintained functional capillary density (P<0.01) and capillary recruitment capacity (P=0.04) with no changes in capillary blood volume versus those who did not receive milrinone. Children under two years old who received milrinone had better 4-6-micron capillary density than older children [odds ratio (OR) 0.33; 95% confidence interval (95% CI): 0.12-0.89; P=0.02] and less endothelial glycocalyx degradation [adjusted OR (aOR) 0.34 95% CI: 0.11-0.99; P=0.04]. These changes persisted despite elevated ferritin (aOR 0.41; 95% CI: 0.18-0.93; P=0.03). Prolonged capillary refill and elevated lactate were correlated with microcirculation changes in both groups. The patients who died had the highest PBR levels (P=0.04).
CONCLUSIONS
Children with septic shock who receive milrinone infusions have microcirculation changes compared with those who do not receive them. The group that received milrinone was found to maintain functional capillary density and capillary recruitment capacity and have less endothelial glycocalyx degradation 24 hours after administration. These changes were present despite the inflammatory response and were more significant in those under two years of age.
PubMed: 38840690
DOI: 10.21037/tp-23-619 -
Journal of the American Society of... Apr 2024Rapid On-Site Evaluation of cytological samples obtained through fine needle aspiration for adequacy is a critical component of a cytology service; however, it imposes a...
INTRODUCTION
Rapid On-Site Evaluation of cytological samples obtained through fine needle aspiration for adequacy is a critical component of a cytology service; however, it imposes a significant time and cost burden for the practicing pathologist and the cytology service. Telecytology enables adequacy assessment by a pathologist remotely, greatly saving time. Telecytology also allows slide preparation and manipulation at the procedure site by an employee with less training requirements, liberating the cytotechnologist to screen cases and perform other laboratory duties - an important aspect to consider during times of cytotechnologist shortages. We propose a telecytology system with a simple setup of a microscope, microscope camera, laptop, and Microsoft Teams software.
MATERIALS AND METHODS
We designed a system consisting of a mobile cart, backup battery, microscope, digital camera, and a laptop computer with microscope imaging software and Microsoft Teams software for image transmission. Validation was performed by 4 pathologists making adequacy assessments on randomly selected previously signed out cases using the telecytology system.
RESULTS
Our validation of this system demonstrated a greater than 90% concurrence rate between the original adequacy call and the call made by pathologists using the telecytology system - a benchmark used by most, if not all, published validations of similar telecytology systems. In addition, the adequacy assessment concordance rate between select pathologists exceeded 90%.
CONCLUSIONS
In summary, our telecytology system provides excellent adequacy services for the clinicians and patients we serve. The Microsoft Teams software is a great tool for transmission of video microscopy. This system will be used with the goal of saving time and increasing efficiency for the cytopathology department.
PubMed: 38834385
DOI: 10.1016/j.jasc.2024.04.004 -
PloS One 2024Optical microscopy videos enable experts to analyze the motion of several biological elements. Particularly in blood samples infected with Trypanosoma cruzi (T. cruzi),...
Optical microscopy videos enable experts to analyze the motion of several biological elements. Particularly in blood samples infected with Trypanosoma cruzi (T. cruzi), microscopy videos reveal a dynamic scenario where the parasites' motions are conspicuous. While parasites have self-motion, cells are inert and may assume some displacement under dynamic events, such as fluids and microscope focus adjustments. This paper analyzes the trajectory of T. cruzi and blood cells to discriminate between these elements by identifying the following motion patterns: collateral, fluctuating, and pan-tilt-zoom (PTZ). We consider two approaches: i) classification experiments for discrimination between parasites and cells; and ii) clustering experiments to identify the cell motion. We propose the trajectory step dispersion (TSD) descriptor based on standard deviation to characterize these elements, outperforming state-of-the-art descriptors. Our results confirm motion is valuable in discriminating T. cruzi of the cells. Since the parasites perform the collateral motion, their trajectory steps tend to randomness. The cells may assume fluctuating motion following a homogeneous and directional path or PTZ motion with trajectory steps in a restricted area. Thus, our findings may contribute to developing new computational tools focused on trajectory analysis, which can advance the study and medical diagnosis of Chagas disease.
Topics: Trypanosoma cruzi; Microscopy, Video; Chagas Disease; Humans; Image Processing, Computer-Assisted
PubMed: 38829872
DOI: 10.1371/journal.pone.0304716 -
Journal of Visualized Experiments : JoVE May 2024Microglia are highly dynamic cells and their migration and colonization of the brain parenchyma is a crucial step for proper brain development and function. Externally...
Microglia are highly dynamic cells and their migration and colonization of the brain parenchyma is a crucial step for proper brain development and function. Externally developing zebrafish embryos possess optical transparency, which along with well-characterized transgenic reporter lines that fluorescently label microglia, make zebrafish an ideal vertebrate model for such studies. In this paper, we take advantage of the unique features of the zebrafish model to visualize the dynamics of microglia cells in vivo and under physiological conditions. We use confocal microscopy to record a timelapse of microglia cells in the optic tectum of the zebrafish embryo and then, extract tracking data using the IMARIS 10.0 software to obtain the cells' migration path, mean speed, and distribution in the optic tectum at different developmental stages. This protocol can be a useful tool to elucidate the physiological significance of microglia behavior in various contexts, contributing to a deeper characterization of these highly motile cells.
Topics: Animals; Zebrafish; Microglia; Microscopy, Confocal; Cell Movement; Superior Colliculi; Embryo, Nonmammalian
PubMed: 38829132
DOI: 10.3791/66533 -
Open Veterinary Journal Apr 2024The developmental biology of is described, based on the phenotype. This species is important for the flora because they are excellent seed disseminators. In addition,...
BACKGROUND
The developmental biology of is described, based on the phenotype. This species is important for the flora because they are excellent seed disseminators. In addition, basic embryological information is not yet fully clarified, and this research provides unprecedented information on the chelonian embryology of the Amazonian fauna.
AIM
The present study aims to identify the embryology of in captivity during different periods.
METHODS
Females were monitored throughout the reproductive cycle, by video monitoring, to identify nests and the presence of newly laid eggs. At regular weekly intervals, embryo samples were collected fixed in a 4% paraformol solution and preserved in 70% alcohol. For the embryonic characterization, we used a stereomicroscope and the scanning electron microscopy method.
RESULTS
We describe 15 embryonic stages for a 15-week (105-day) incubation process. Only at 42 days (6th week) was the morphological characterization of a chelonian observed and at the 12th week (Stage XII), the phenotypic characterization of the species .
CONCLUSION
In view of the evidence, we found that these phases are similar to the other turtles, with structural variations in the appearance and disappearance of structures due to the specific characteristics of the species.
Topics: Animals; Turtles; Female; Embryonic Development; Embryo, Nonmammalian; Microscopy, Electron, Scanning
PubMed: 38808293
DOI: 10.5455/OVJ.2024.v14.i4.3