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Describes a range of physical techniques that can be applied to bacterial biophysics including sample culture, flow cytometry, microscopy, photonics, NMR, mass spectrometry and electrophoresis.
Schistosomiasis is a neglected tropical disease with significant health implications, particularly among children. A cross-sectional study was conducted among school-aged children (SAC) in Mwanga district, Tanzania, a region known to be co-endemic for S. haematobium and S. mansoni infection and where annual mass drug administration (MDA) has been conducted for 20 years. In total, 576 SAC from 5 schools provided a urine sample for the detection of Schistosoma circulating anodic antigen using the upconverting particle-based lateral flow (UCP-LF CAA) test. Additionally, the potential of the point-of-care circulating cathodic antigen (POC-CCA) and microhaematuria dipstick test as field-applicable diagnostic alternatives for schistosomiasis were assessed and the prevalence outcome compared to UCP-LF CAA. Risk factors associated with schistosomiasis was assessed based on UCP-LF CAA. The UCP-LF CAA test revealed an overall schistosomiasis prevalence of 20.3%, compared to 65.3% based on a combination of POC-CCA and microhaematuria dipstick. No agreement was observed between the combined POC tests and UCP-LF CAA. Factors associated with schistosomiasis included age (5–10 years), involvement in fishing, farming, swimming activities and attending 2 of the 5 primary schools. Our findings suggest a significant progress in infection control in Mwanga district due to annual MDA, although not enough to interrupt transmission. Accurate diagnostics play a crucial role in monitoring intervention measures to effectively combat schistosomiasis.
This chapter is a discussion of methods used to study the nervous system at the level of cells. The introduction defines and describes the microanatomy of neurons and populations of glia and gives an overview of organelles. Next is a discussion of microscopy techniques and images, including light microscopy (bright-field and fluorescence) and electron microscopy. Other techniques which rely on microscopy are then described, including unbiased stereology, fluorescence recovery after photobleaching, and flow cytometry. The chapter concludes with a description of a variety of stains, dyes, and anterograde and retrograde tracers, as well as an interpretation of Sholl analysis figures and dendritic spine quantification.
Supervised deep learning approaches can artificially increase the resolution of microscopy images by learning a mapping between two image resolutions or modalities. However, such methods often require a large set of hard-to-get low-res/high-res image pairs and produce synthetic images with a moderate increase in resolution. Conversely, recent methods based on generative adversarial network (GAN) latent search offered a drastic increase in resolution without the need of paired images. However, they offer limited reconstruction of the high-resolution (HR) image interpretable features. Here, we propose a robust super-resolution (SR) method based on regularized latent search (RLS) that offers an actionable balance between fidelity to the ground truth (GT) and realism of the recovered image given a distribution prior. The latter allows to split the analysis of a low-resolution (LR) image into a computational SR task performed by deep learning followed by a quantification task performed by a handcrafted algorithm based on interpretable biological features. This two-step process holds potential for various applications such as diagnostics on mobile devices, where the main aim is not to recover the HR details of a specific sample but rather to obtain HR images that preserve explainable and quantifiable differences between conditions.
Although viral protein structure and replication mechanisms have been explored extensively with X-ray crystallography, cryo-electron microscopy, and population imaging studies, these methods are often not able to distinguish dynamic conformational changes in real time. Single-molecule fluorescence resonance energy transfer (smFRET) offers unique insights into interactions and states that may be missed in ensemble studies, such as nucleic acid or protein structure, and conformational transitions during folding, receptor–ligand interactions, and fusion. We discuss the application of smFRET to the study of viral protein conformational dynamics, with a particular focus on viral glycoprotein dynamics, viral helicases, proteins involved in HIV reverse transcription, and the influenza RNA polymerase. smFRET experiments have played a crucial role in deciphering conformational changes in these processes, emphasising the importance of smFRET as a tool to help elucidate the life cycle of viral pathogens and identify key anti-viral targets.
Infection with the parasitic nematode Strongyloides stercoralis is characteristic for tropical and subtropical regions of the world, but autochthonous cases have been reported in European countries as well. Here we present the first nation-wide survey of S. stercoralis seroprevalence in Croatian individuals presenting with eosinophilia, and evaluate the fraction of positive microscopy rates in stool specimens of seropositive individuals. In our sample of 1407 patients tested between 2018 and 2021, the overall prevalence of strongyloidiasis was 9.31%, with significantly higher rates in those older than 60 years of age (P = 0.005). Of those, one-quarter (25.95%) were also positive following microscopy examination of faeces after using the merthiolate–iodine–formaldehyde concentration method. Our findings reinforce the notion of endemic strongyloidiasis transmission in Croatia, particularly in older individuals, and highlight the need to consider the presence of S. stercoralis in patients with eosinophilia.
The ant in Robert Hooke’s compendium and celebration of microscopy in Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses (1665) uniquely resists scientific scrutiny: moving about when alive, too-easily crushed when dead, the ant proves to be insistently difficult to study under a microscope. Through an extended allusion to Richard Ligon’s A True and Exact History of the Island of Barbadoes (1657), Hooke links the unruly ant to the colonial economy of enslaved Africans in Barbados, a place that Ligon understands through sugarcane, enslaved Africans, and saltwater slavery. The story of Hooke’s ant in Micrographia uncovers what Lisa Lowe calls the “intimacy” of modern, Western liberalism and the global conditions upon which it depends. In this case, Hooke’s ant reveals the intimacy of early scientific practice and the institution of transatlantic chattel slavery, exposing in the process that a small thing can reveal vast scales of geography and their networks of exploitation.
The raw materials of “licorice root” in the commerce consist of roots and/or rhizomes (stolons) of different species of Glycyrrhiza. Licorice products and raw materials are frequently mislabeled and often have mixed, misidentified, or unidentified species and parts. This paper provides a detailed comparative analysis of the morpho-anatomies of the rhizomes and roots of five species of Glycyrrhiza, namely G. glabra, G. uralensis, G. echinata, G. inflata, and G. lepidota, by bright-field light microscopy and scanning electron microscopy. The studied species showed some similarities in their basic anatomical features due to the fact that they are phylogenetically closely related and belong to the same genus. However, differences in microscopic features such as the thickness of cork and medullary rays, pore frequency, and size of the vessels were observed. The rhizomes can readily be distinguished by the presence of a distinct pith. The roots lack a well-defined pith and instead have primary xylem in the center.
Bipolar disorder has been repeatedly associated with abnormalities of white matter. However, DTI is intrinsically limited and the precise cellular mechanisms that underlie these alterations remains unknown.
Objectives
Our aim was to investigate microscopical characteristics of white matter using MRI in patients with bipolar and healthy controls.
Methods
77 patients and 71 controls from 3 sites had a T1 structural MRI, a multi-shell HARDI MRI and at one site with a T1-weighted VFA-SPGR acquisition, and a T2 MSME acquisition. The volume fraction and the orientation dispersion was extracted using NODDI from DW images in each site. Myelin Water Fraction was extracted in 33 patients and 36 controls to probe myelin characteristics. White matter bundles were reconstructed using deterministic tractography. Statistical analyses were performed after harmonization by the ComBat algorithm and controlled for age, gender and handedness.
Results
We found significant lower axonal density in patients along the short fibers of the left cingulum, the left anterior arcuate and the left inferior fronto-occipital fasciculus. We found lower mean MWF in patients along the short fibers of the right cingulum, the left inferior fronto-occipital fasciculus, the left anterior arcuate and the splenium of the corpus callosum. We found higher mean orientation dispersion in patients only along the left uncinate fasciculus.
Conclusions
We report alterations of limbic and inter-hemispheric white matter tracts in patients with bipolar disorder reflecting axonal loss, demyelination and architecture alterations. These results contribute to better capture the plurality of the mechanisms involved in bipolar disorder that cannot be deciphered with classical diffusion MRI.
Many universities, commercial companies, and science organizations who use microscopy have outreach programs. The members of such generally love to share their enthusiasm and passion with the next generation. Content and confidence on providing such a program often comes from sharing ideas with like-minded scientists. These programs are typically delegated with the acronym STEM or STEAM: science, technology, engineering, art, and math. One of MSA's outreach programs is ProjectMICRO. Included are some STEAM ideas to share.
This study aimed to reveal the anatomical features of the bovine eye by scanning electron and light microscopic methods. For this purpose, a total of 40 eyes were evaluated. Gross and microscopic characteristics of the cornea, sclera, ciliary body, choroid, iris, and lens were determined. Bowman's and Descemet's membranes of the cornea were quite dense and prominent. Collagen lamellae of the cornea were wavy in the periphery and more parallel to the basal and metachromatic fibroblasts were noted. Three to four ciliary plicae merged to form ciliary processes. The presence of prominent intermediate bands connecting the ciliary plicae was determined. The zonular fibrils merged and attached to the lens in the form of thick zonular bands. A dense corpora nigra was present at the rectangular pupillary border of the iris. Tapetum fibrosum, consisting of polygonal tapetal cells, was in blue-yellow-green color and covered most of the choroid. A complex drainage system consisting of trabecular meshwork, angular aqueous plexus, ciliary sinus, and scleral venous vessels localized in a fairly wide iridocorneal angle was identified. Identifying structural features of the bovine eye is very important and useful for pathological evaluations, understanding species-specific physiological mechanisms and for operative interventions of ruminant species.
Cryo-soft-X-ray tomography is being increasingly used in biological research to study the morphology of cellular compartments and how they change in response to different stimuli, such as viral infections. Segmentation of these compartments is limited by time-consuming manual tools or machine learning algorithms that require extensive time and effort to train. Here we describe Contour, a new, easy-to-use, highly automated segmentation tool that enables accelerated segmentation of tomograms to delineate distinct cellular compartments. Using Contour, cellular structures can be segmented based on their projection intensity and geometrical width by applying a threshold range to the image and excluding noise smaller in width than the cellular compartments of interest. This method is less laborious and less prone to errors from human judgement than current tools that require features to be manually traced, and it does not require training datasets as would machine-learning driven segmentation. We show that high-contrast compartments such as mitochondria, lipid droplets, and features at the cell surface can be easily segmented with this technique in the context of investigating herpes simplex virus 1 infection. Contour can extract geometric measurements from 3D segmented volumes, providing a new method to quantitate cryo-soft-X-ray tomography data. Contour can be freely downloaded at github.com/kamallouisnahas/Contour.
The seventeenth-century microscopists Robert Hooke and Henry Power sought to rhetorically establish the truthfulness of the visual images produced by their instruments, but a counter-rhetoric of visuality was established by Margaret Cavendish in Observations upon Experimental Philosophy (1666). The microscopists’ belief that magnification revealed the truth of nature ran counter to Cavendish’s probabilistic belief that no individual could grasp the infinite truth of nature and sought explanations from the superficies of observed objects rather than the ‘interior figurative motions’ which Cavendish saw as the universal cause of all natural phenomena. While the microscopists emphasized the aesthetic beauty of the micro-visible world, Cavendish emphasized its monstrosity: for her the truth could only be perceived by the ‘natural’ eye observing things in their unmagnified state. Exploiting the microscopists’ complaints about the variability of their images and the defects of their instruments Cavendish redefines the microscopic image as definitively outside the ‘real’.
Advancements in high content image analysis have led to an increase in the adoption of these techniques in basic science and clinical research. High-throughput approaches to imaging and image analysis require minimal user interventions, circumventing the often prohibitively time-consuming and unreliable standard manual analysis. In this study, we demonstrate how high content imaging (HCI) techniques, in combination with high content analysis (HCA), can be paired with more traditional manual analysis to quantify both micro- and macro-level features of biopsied tissue sections. High-resolution, full-color images of stained tissue were acquired and stitched together to reconstruct the entire tissue section, which enabled analyses that required accurate identification of a given region's location within the tissue section. A custom region of interest grid was generated that followed the curvature of the tissue. The composite images were used in two separate analyses: tissue layer thickness as a macro-level approach, and nuclei density as a micro-level approach. Ultimately, the flexibility of the HCI and HCA methodologies used in this study allowed for complex analysis of tissue that would not have been otherwise feasible.
Counting dental acellular cementum (AC) annulations is used to estimate age at death in anthropological contexts by embedding the tooth, sectioning the root, and imaging the thin sections. However, there are several published protocols creating confusion to optimize these steps. We compared three standard illumination techniques (differential interference contrast; transmitted bright field; transmitted polarized) on sections with the same thickness, field of view, on three types of samples: fresh teeth embedded in both MMA and epoxy; archeological samples embedded in epoxy. We compared the quality of AC increment visibility on longitudinal and transversal sections of the same root, to optimize the quality of AC micrographs for age estimation. Results suggest that differential interference contrast microscopy might be ideal, even though brightfield consistently provides a decent image; epoxy resin with quick polymerization time doesn't affect AC structure and allows for higher contrast than traditional MMA; transverse sections are more consistent. These results emphasize the need for cementum-specific procedures not always compatible with traditional dental analyses.
The morphology and composition of the corrosion products of archaeological arsenical copper alloys buried in a specific environment for a long time were investigated using optical microscopy (OM), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), micro X-ray fluorescence (μ-XRF), and X-ray diffraction (XRD). The analyses demonstrated that the alloy composition of the artifacts was copper-arsenic (Cu-AS) with significant amounts of lead in some samples. Cuprite, malachite, and copper (II) hydroxychlorides were observed on a completely mineralized matrix. The surface of the objects was covered by two main corrosion layers formed on the internal cuprous oxide. However, several successive layers of corrosion products were recognized on the artifacts in some cases. Furthermore, phosphatic corrosion products including, mimetite [Pb5(AsO4)3Cl], and pyromorphite [Pb5(PO4)3Cl] were identified. Conichalcite [CaCu(AsO4)](OH), which grew in the form of Liesegang rings, was also identified as a corrosion product of one of the objects. As and Pb exhibited some enrichment in the corrosion crusts of the artifacts. Environmental changes in burial conditions, particularly due to seasonal streams and consequent changes in soil corrosivity, vicinity of objects to bone material, along with the migration of alloy elements, especially lead and arsenic, can explain the morphological features of these archaeological objects.
To compare the efficacy and safety characteristics of endoscopic and microscopic stapes surgery based on current evidence.
Methods
A systematic literature search was conducted of three medical databases, focusing on randomised, controlled studies or observational studies. Data related to the efficacy and safety of each technique were extracted. Outcome data were summarised using the pooled mean differences or pooled odds ratios, along with their 95 per cent confidence intervals.
Results
Thirteen studies were included in the meta-analysis. Success rate was evaluated by estimating air–bone gap improvement; this revealed comparable outcomes for the two techniques (mean difference = −0.20; 95 per cent confidence interval = −0.53, 0.14). No statistically significant difference was detected concerning post-operative complications, except for dysgeusia (odds ratio = −1.12; 95 per cent confidence interval = −1.97, −0.28) and pain (odds ratio = −2.00; 95 per cent confidence interval = −2.97, −1.04), which favoured the endoscopic approach.
Conclusion
Though both techniques result in commensurate outcomes concerning success rate, post-operative pain and dysgeusia favour the endoscopic approach. Further high-quality studies are needed to adequately compare the two methods.
Superior semicircular canal dehiscence is an uncommon neurotological disorder in which the petrous temporal bone overlying the superior semicircular canal lacks bone. Its most common symptoms include amplification of internal sounds, autophony, tinnitus, sound- and pressure-induced vertigo, hyperacusis, oscillopsia, and hearing loss. This video presentation aimed to demonstrate endoscopic-assisted repair of superior semicircular canal dehiscence with middle fossa craniotomy.
Method
Eleven patients with superior semicircular canal dehiscence, verified with temporal computed tomography, were enrolled in the study.
Result
An endoscopy-assisted middle fossa approach was applied to all patients. Superior semicircular canal dehiscence was successfully repaired with an endoscope in 11 patients.
Conclusion
Endoscopic-assisted repair of superior semicircular canal dehiscence may be a superior approach compared with binocular operative microscopy.
This paper reports the first case of simultaneous bilateral cochlear implant surgery performed exclusively with a three-dimensional exoscope. It also discusses the optimum operative set-up and the feasibility of three-dimensional exoscopic ear surgery as an alternative to the microscope.
Method
The Vitom three-dimensional exoscope system (Karl Storz) was used.
Results
The surgery was successfully completed, with no peri-operative complications. Both the operation time and the surgical outcome for the patient were comparable with the previous cochlear implant surgical procedures performed in our centre using the conventional operating microscope.
Conclusion
This paper demonstrates that exclusive use of the three-dimensional exoscope is a viable alternative to the operating microscope for selected otological cases. It is clear that the three-dimensional exoscopic technique is potentially very promising for future surgical procedures, provided that cases are selected carefully to prevent compromising exposure, efficiency or patient safety.