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1.
Opt Express ; 31(1): 598-609, 2023 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-36606995

RESUMO

The lateral resolution of the optical-resolution photoacoustic microscopy (OR-PAM) system depends on the focusing diameter of the probe beam. By increasing the numerical aperture (NA) of optical focusing, the lateral resolution of OR-PAM can be improved. However, the increase in NA results in smaller working distances, and the entire imaging system becomes very sensitive to small optical imperfections. The existing deconvolution-based algorithms are limited by the image signal-to-noise ratio when improving the resolution of OR-PAM images. In this paper, a super-resolution reconstruction algorithm for OR-PAM images based on sparsity and deconvolution is proposed. The OR-PAM image is sparsely reconstructed according to the constructed loss function, which utilizes the sparsity of the image to combat the decrease in the resolution. The gradient accelerated Landweber iterative algorithm is used to deconvolve to obtain high-resolution OR-PAM images. Experimental results show that the proposed algorithm can improve the resolution of mouse retinal images by approximately 1.7 times without increasing the NA of the imaging system. In addition, compared to the Richardson-Lucy algorithm, the proposed algorithm can further improve the image resolution and maintain better imaging quality, which provides a foundation for the development of OR-PAM in clinical research.


Assuntos
Dispositivos Ópticos , Técnicas Fotoacústicas , Camundongos , Animais , Microscopia/métodos , Razão Sinal-Ruído , Algoritmos , Processamento de Imagem Assistida por Computador/métodos , Técnicas Fotoacústicas/métodos
2.
Appl Opt ; 62(1): 255-259, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36606872

RESUMO

As an important part of optical-resolution photoacoustic microscopy, the acoustic lens is responsible for efficient collection of photoacoustic signals. The spherical focused acoustic lens is commonly used in photoacoustic microscopy because of its efficient detection of the photoacoustic signal in the focus area. However, the narrow depth of field of the spherical focused acoustic lens limits the expansion of the depth of field of the photoacoustic microscopy. To solve this problem, a Bessel acoustic-beam acoustic lens is proposed. The Bessel acoustic-beam acoustic lens replaces the spherical concave surface with a conical concave surface to generate a Bessel acoustic beam with non-diffraction. Using the simulation model of Bessel acoustic-beam acoustic lens constructed by COMSOL Multiphysics, it is verified theoretically that the Bessel acoustic-beam acoustic lens can improve the depth of field of detection by ∼2 times. The Bessel acoustic-beam acoustic lens can further promote the capability of high-speed and large volumetric imaging of optical-resolution photoacoustic microscopy and will be helpful in the acquisition of physiological and pathological processes.


Assuntos
Lentes , Microscopia , Microscopia/métodos , Simulação por Computador , Análise Espectral , Acústica
3.
Nat Commun ; 14(1): 105, 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36609405

RESUMO

Myelination processes are closely related to higher brain functions such as learning and memory. While their longitudinal observation has been crucial to understanding myelin-related physiology and various brain disorders, skull opening or thinning has been required to secure clear optical access. Here we present a high-speed reflection matrix microscope using a light source with a wavelength of 1.3 µm to reduce tissue scattering and aberration. Furthermore, we develop a computational conjugate adaptive optics algorithm designed for the recorded reflection matrix to optimally compensate for the skull aberrations. These developments allow us to realize label-free longitudinal imaging of cortical myelin through an intact mouse skull. The myelination processes of the same mice were observed from 3 to 10 postnatal weeks to the depth of cortical layer 4 with a spatial resolution of 0.79 µm. Our system will expedite the investigations on the role of myelination in learning, memory, and brain disorders.


Assuntos
Encefalopatias , Microscopia , Camundongos , Animais , Bainha de Mielina , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Crânio/fisiologia
4.
Sci Rep ; 13(1): 263, 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36609620

RESUMO

Neural tube closure (NTC) is a complex process of embryonic development involving molecular, cellular, and biomechanical mechanisms. While the genetic factors and biochemical signaling have been extensively investigated, the role of tissue biomechanics remains mostly unexplored due to the lack of tools. Here, we developed an optical modality that can conduct time-lapse mechanical imaging of neural plate tissue as the embryo is experiencing neurulation. This technique is based on the combination of a confocal Brillouin microscope and a modified ex ovo culturing of chick embryo with an on-stage incubator. With this technique, for the first time, we captured the mechanical evolution of the neural plate tissue with live embryos. Specifically, we observed the continuous increase in tissue modulus of the neural plate during NTC for ex ovo cultured embryos, which is consistent with the data of in ovo culture as well as previous studies. Beyond that, we found that the increase in tissue modulus was highly correlated with the tissue thickening and bending. We foresee this non-contact and label-free technique opening new opportunities to understand the biomechanical mechanisms in embryonic development.


Assuntos
Microscopia , Neurulação , Animais , Feminino , Gravidez , Embrião de Galinha , Microscopia/métodos , Tubo Neural , Imagem com Lapso de Tempo , Desenvolvimento Embrionário
5.
Sci Rep ; 13(1): 281, 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36609672

RESUMO

In this contribution, we demonstrate a wide-field hyperspectral mid-infrared (MIR) microscope based on multidimensional single-pixel imaging (SPI). The microscope employs a high brightness MIR supercontinuum source for broadband (1.55 [Formula: see text]-4.5 [Formula: see text]) sample illumination. Hyperspectral imaging capability is achieved by a single micro-opto-electro-mechanical digital micromirror device (DMD), which provides both spatial and spectral differentiation. For that purpose the operational spectral bandwidth of the DMD was significantly extended into the MIR spectral region. In the presented design, the DMD fulfills two essential tasks. On the one hand, as standard for the SPI approach, the DMD sequentially masks captured scenes enabling diffraction-limited imaging in the tens of millisecond time-regime. On the other hand, the diffraction at the micromirrors leads to dispersion of the projected field and thus allows for wavelength selection without the application of additional dispersive optical elements, such as gratings or prisms. In the experimental part, first of all, the imaging and spectral capabilities of the hyperspectral microscope are characterized. The spatial and spectral resolution is assessed by means of test targets and linear variable filters, respectively. At a wavelength of 4.15 [Formula: see text] a spatial resolution of 4.92 [Formula: see text] is achieved with a native spectral resolution better than 118.1 nm. Further, a post-processing method for drastic enhancement of the spectral resolution is proposed and discussed. The performance of the MIR hyperspectral microsopce is demonstrated for label-free chemical imaging and examination of polymer compounds and red blood cells. The acquisition and reconstruction of Hadamard sampled 64 [Formula: see text] 64 images is achieved in 450 ms and 162 ms, respectively. Thus, combined with an unprecedented intrinsic flexibiliy gained by a tunable field of view and adjustable spatial resolution, the demonstrated design drastically improves the sample throughput in MIR chemical and biomedical imaging.


Assuntos
Microscopia , Dispositivos Ópticos , Iluminação , Desenho de Equipamento
6.
Sci Rep ; 13(1): 524, 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36627360

RESUMO

Illustrated papyruses from Ancient Egypt have survived across millennia, depicting with vivid colors numerous stories and practices from a distant past. We have investigated a series of illustrated papyruses from Champollion's private collection showing scenes from the Book of the Dead, a document essential to prepare for the afterlife. The nature of the different pigments and their distribution are revealed by combining optical microscopy, Raman spectroscopy, and synchrotron X-ray powder diffraction and fluorescence. The standardized three-step process from the New Kingdom period was used, comprising a preparatory drawing made of red hematite, a coloring step using pigments from the Egyptian palette, and a final black contour drawn with a carbon-based ink. Interestingly, specific pigment mixes were deliberately chosen to obtain different shades. In some parts, the final contour significantly differs from the preliminary drawing, revealing the artist's creativity. These results enhance our knowledge of illustrative practices in Ancient Egypt.


Assuntos
Microscopia , Análise Espectral Raman , História Antiga , Antigo Egito , Egito
7.
BMC Cancer ; 23(1): 38, 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36627575

RESUMO

BACKGROUND: Gastrointestinal stromal tumor (GIST) is currently regarded as a potentially malignant tumor, and early diagnosis is the best way to improve its prognosis. Therefore, it will be meaningful to develop a new method for auxiliary diagnosis of this disease. METHODS: Here we try out a new means to detect GIST by combining two-photon imaging with automatic image processing strategy. RESULTS: Experimental results show that two-photon microscopy has the ability to label-freely identify the structural characteristics of GIST such as tumor cells, desmoplastic reaction, which are entirely different from those from gastric adenocarcinoma. Moreover, an image processing approach is used to extract eight collagen morphological features from tumor microenvironment and normal muscularis, and statistical analysis demonstrates that there are significant differences in three features-fiber area, density and cross-link density. The three morphological characteristics may be considered as optical imaging biomarkers to differentiate between normal and abnormal tissues. CONCLUSION: With continued improvement and refinement of this technology, we believe that two-photon microscopy will be an efficient surveillance tool for GIST and lead to better management of this disease.


Assuntos
Tumores do Estroma Gastrointestinal , Neoplasias Gástricas , Humanos , Tumores do Estroma Gastrointestinal/diagnóstico por imagem , Tumores do Estroma Gastrointestinal/patologia , Microscopia , Neoplasias Gástricas/patologia , Prognóstico , Colágeno , Microambiente Tumoral
8.
Bioinformatics ; 39(1)2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36629475

RESUMO

SUMMARY: Advances in 3D live cell microscopy are enabling high-resolution capture of previously unobserved processes. Unleashing the power of modern machine learning methods to fully benefit from these technologies is, however, frustrated by the difficulty of manually annotating 3D training data. MiCellAnnGELo virtual reality software offers an immersive environment for viewing and interacting with 4D microscopy data, including efficient tools for annotation. We present tools for labelling cell surfaces with a wide range of applications, including cell motility, endocytosis and transmembrane signalling. AVAILABILITY AND IMPLEMENTATION: MiCellAnnGELo employs the cross-platform (Mac/Unix/Windows) Unity game engine and is available under the MIT licence at https://github.com/CellDynamics/MiCellAnnGELo.git, together with sample data. MiCellAnnGELo can be run in desktop mode on a 2D screen or in 3D using a standard VR headset with a compatible GPU. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Microscopia , Realidade Virtual , Fatores de Tempo , Software , Membrana Celular
9.
J Chem Phys ; 158(3): 034201, 2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36681638

RESUMO

Charge modulation microscopy (CMM) is an electro-optical method that is capable of mapping the spatial distribution of induced charges in an organic field-effect transistor (OFET). Here, we report a new (and simple) implementation of CMM in transmission geometry with camera-based imaging. A significant improvement in data acquisition speed (by at least an order of magnitude) has been achieved while preserving the spatial and spectral resolution. To demonstrate the capability of the system, we measured the spatial distribution of the induced charges in an OFET with a polymer blend of indacenodithiophene-co-benzothiadiazole and poly-vinylcarbazole that shows micrometer-scale phase separation. We were able to resolve spatial variations in the accumulated charge density on a length scale of 500 nm. We demonstrated through a careful spectral analysis that the measured signal is a genuine charge accumulation signal that is not dominated by optical artifacts.


Assuntos
Microscopia , Polímeros
10.
Comput Biol Med ; 153: 106499, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36599208

RESUMO

The automated segmentation and tracking of macrophages during their migration are challenging tasks due to their dynamically changing shapes and motions. This paper proposes a new algorithm to achieve automatic cell tracking in time-lapse microscopy macrophage data. First, we design a segmentation method employing space-time filtering, local Otsu's thresholding, and the SUBSURF (subjective surface segmentation) method. Next, the partial trajectories for cells overlapping in the temporal direction are extracted in the segmented images. Finally, the extracted trajectories are linked by considering their direction of movement. The segmented images and the obtained trajectories from the proposed method are compared with those of the semi-automatic segmentation and manual tracking. The proposed tracking achieved 97.4% of accuracy for macrophage data under challenging situations, feeble fluorescent intensity, irregular shapes, and motion of macrophages. We expect that the automatically extracted trajectories of macrophages can provide pieces of evidence of how macrophages migrate depending on their polarization modes in the situation, such as during wound healing.


Assuntos
Microscopia , Filmes Cinematográficos , Animais , Algoritmos , Rastreamento de Células , Processamento de Imagem Assistida por Computador/métodos
11.
Biosens Bioelectron ; 224: 115049, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36623342

RESUMO

Imaging a large number of bio-specimens at high speed is essential for many biomedical applications. The common strategy is to place specimens at different lateral positions and image them sequentially. Here we report a new on-chip imaging strategy, termed depth-multiplexed ptychographic microscopy (DPM), for parallel imaging and sensing at high speed. Different from the common strategy, DPM stacks multiple specimens in the axial direction and images the entire z-stack all at once. In our prototype platform, we modify a low-cost car mirror for programmable steering of the incident laser beam. A blood-coated image sensor is then placed underneath the stacked sample for acquiring the resulting diffraction patterns. With the captured images, we perform blind recovery of the incident beam angle and model different layers of the stacked sample as different coded surfaces for object reconstruction. For in vitro experiment, we demonstrate time-lapse cell culture monitoring by imaging 3 stacked microfluidic channels on the coded sensor. For high-throughput cytometric analysis, we image 5 stacked brain sections with a 205-mm2 field of view in ∼50 s. Cytometric analysis is also performed to quantify the cellular proliferation biomarkers on the slides. The DPM approach adds a new degree of freedom for data multiplexing in microscopy, enabling parallel imaging of multiple specimens using a single detector. The demonstrated 6-mm depth of field is among the longest ones in microscopy imaging. The novel depth-multiplexed configuration also complements the miniaturization provided by microfluidics devices, offering a solution for on-chip sensing and imaging with efficient sample handling.


Assuntos
Técnicas Biossensoriais , Microscopia , Dispositivos Lab-On-A-Chip , Luz , Microfluídica
12.
J Helminthol ; 97: e10, 2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36651325

RESUMO

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.


Assuntos
Eosinofilia , Strongyloides stercoralis , Estrongiloidíase , Idoso , Animais , Humanos , Croácia/epidemiologia , Eosinofilia/epidemiologia , Eosinofilia/parasitologia , Microscopia , Estudos Soroepidemiológicos , Estrongiloidíase/diagnóstico , Estrongiloidíase/epidemiologia
13.
Anal Chem ; 95(2): 1541-1548, 2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36595491

RESUMO

Multiplexed protein detection is critical for improving the drug and biomarker screening efficiency. Here, we show that multiplexed protein detection and parallel protein interaction analysis can be realized by evanescent scattering microscopy (ESM). ESM enables binding kinetics measurement with label-free digital single-molecule counting. We implemented an automatic single-molecule counting strategy with high temporal resolution to precisely determine the binding time, which improves the counting efficiency and accuracy. We show that digital single-molecule counting can recognize proteins with different molecular weights, thus making it possible to monitor the protein binding processes in the solution by real-time tracking of the numbers of free and bound proteins landing on the sensor surface. Furthermore, we show that this strategy can simultaneously analyze the kinetics of two different protein interaction processes on the surface and in the solution. This work may pave a way to investigate complicated protein interactions, such as the competition of biomarker-antibody binding in biofluids with biomarker-protein binding on the cellular membrane.


Assuntos
Microscopia , Proteínas , Proteínas/metabolismo , Membrana Celular/metabolismo , Nanotecnologia , Biomarcadores/metabolismo , Cinética , Ligação Proteica
14.
Math Biosci Eng ; 20(1): 318-336, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36650768

RESUMO

We incorporate a practical data assimilation methodology into our previously established experimental-computational framework to predict the heterogeneous response of glioma cells receiving fractionated radiation treatment. Replicates of 9L and C6 glioma cells grown in 96-well plates were irradiated with six different fractionation schemes and imaged via time-resolved microscopy to yield 360- and 286-time courses for the 9L and C6 lines, respectively. These data were used to calibrate a biology-based mathematical model and then make predictions within two different scenarios. For Scenario 1, 70% of the time courses are fit to the model and the resulting parameter values are averaged. These average values, along with the initial cell number, initialize the model to predict the temporal evolution for each test time course (10% of the data). In Scenario 2, the predictions for the test cases are made with model parameters initially assigned from the training data, but then updated with new measurements every 24 hours via four versions of a data assimilation framework. We then compare the predictions made from Scenario 1 and the best version of Scenario 2 to the experimentally measured microscopy measurements using the concordance correlation coefficient (CCC). Across all fractionation schemes, Scenario 1 achieved a CCC value (mean ± standard deviation) of 0.845 ± 0.185 and 0.726 ± 0.195 for the 9L and C6 cell lines, respectively. For the best data assimilation version from Scenario 2 (validated with the last 20% of the data), the CCC values significantly increased to 0.954 ± 0.056 (p = 0.002) and 0.901 ± 0.061 (p = 8.9e-5) for the 9L and C6 cell lines, respectively. Thus, we have developed a data assimilation approach that incorporates an experimental-computational system to accurately predict the in vitro response of glioma cells to fractionated radiation therapy.


Assuntos
Neoplasias Encefálicas , Glioma , Humanos , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/metabolismo , Glioma/radioterapia , Glioma/metabolismo , Modelos Teóricos , Linhagem Celular , Microscopia
15.
Sensors (Basel) ; 23(2)2023 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-36679502

RESUMO

Non-destructive measurements of internal morphological structures in plant materials such as seeds are of high interest in agricultural research. The estimation of pericarp thickness is important to understand the grain quality and storage stability of seeds and can play a crucial role in improving crop yield. In this study, we demonstrate the applicability of fiber-based Bessel beam Fourier domain (FD) optical coherence microscopy (OCM) with a nearly constant high lateral resolution maintained at over ~400 µm for direct non-invasive measurement of the pericarp thickness of two different sorghum genotypes. Whereas measurements based on axial profiles need additional knowledge of the pericarp refractive index, en-face views allow for direct distance measurements. We directly determine pericarp thickness from lateral sections with a 3 µm resolution by taking the width of the signal corresponding to the pericarp at the 1/e threshold. These measurements enable differentiation of the two genotypes with 100% accuracy. We find that trading image resolution for acquisition speed and view size reduces the classification accuracy. Average pericarp thicknesses of 74 µm (thick phenotype) and 43 µm (thin phenotype) are obtained from high-resolution lateral sections, and are in good agreement with previously reported measurements of the same genotypes. Extracting the morphological features of plant seeds using Bessel beam FD-OCM is expected to provide valuable information to the food processing industry and plant breeding programs.


Assuntos
Microscopia , Sorghum , Microscopia/métodos , Melhoramento Vegetal , Grão Comestível , Genótipo , Tomografia de Coerência Óptica/métodos
16.
Nature ; 613(7945): 615, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36658357

Assuntos
Microscopia
17.
Anal Chem ; 95(4): 2168-2175, 2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36638088

RESUMO

Characterization of lignocellulosic biomass microstructure with chemical specificity and under physiological conditions could provide invaluable insights to our understanding of plant tissue development, microstructure, origins of recalcitrance, degradation, and solubilization. However, most methods currently available are either destructive, are not compatible with hosting a physiological environment, or introduces exogenous probes, complicating their use for studying changes in microstructure and mechanisms of plant development, recalcitrance, or degradation in situ. To address these challenges, we here present a multi-modal chemically specific imaging technique based on coherent anti-Stokes Raman scattering (CARS) microspectroscopy with simplex maximization and entropy-based spectral unmixing enabling label-free, chemically specific characterization of plant microstructure in liquid. We describe how spatial drift of samples suspended in liquid can introduce artifacts in spectral unmixing procedures for single-frequency CARS and propose a mitigative strategy toward these effects using simultaneously acquired forward-scattered CARS signals and epi-detected autofluorescence. We further apply the technique for chemical and microstructural characterization of untreated and liquid hot water pretreated rapeseed straw by CARS and show how the framework can be extended for 3D imaging with chemical specificity. Finally, we provide examples of the intricate chemical and microstructural details recovered by this hybrid imaging technique, including discerning between primary and secondary cell walls, localization of aqueous components to cell lumina, and the presence of funnel-type pits in samples ofBrassica napus.


Assuntos
Microscopia , Plantas , Biomassa , Biopolímeros , Microscopia/métodos , Análise Espectral Raman/métodos
18.
J Vis Exp ; (191)2023 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-36715404

RESUMO

The formation of biopolymer-based active phases has become an important technique for researchers interested in exploring the emerging field of active liquid crystals and their possible roles in cell biology. These novel systems consist of self-driven sub-units that consume energy locally, producing an out-of-equilibrium dynamic fluid. To form the active liquid crystal phase described in this report, purified protein components including biopolymers and molecular motors are combined, and the active nematic phase spontaneously forms in the presence of adenosine triphosphate (ATP). To observe the nematic state, the material must be confined in a suitable geometry for microscopy at a high enough density. This article describes two different methods for the formation of an active nematic phase using microtubules and kinesin motors: assembly of a two-dimensional active layer at an oil and water interface and assembly under an oil layer using an elastomeric well. Techniques to insert the active material into small wells of different shapes are also described.


Assuntos
Cristais Líquidos , Microtúbulos , Microtúbulos/metabolismo , Trifosfato de Adenosina/metabolismo , Cinesinas/química , Microscopia , Cristais Líquidos/química
19.
Sci Rep ; 13(1): 1599, 2023 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-36709336

RESUMO

With global progress towards malaria reduction stalling, further analysis of epidemiology is required, particularly in countries with the highest burden. National surveys have mostly analysed infection prevalence, while large-scale data on parasite density and different developmental forms rarely available. In Nigeria, the country with the largest burden globally, blood slide microscopy of children up to 5 years of age was conducted in the 2018 National Demographic and Health Survey, and parasite prevalence previously reported. In the current study, malaria parasite density measurements are reported and analysed for 7783 of the children sampled across the 36 states within the six geopolitical zones of the country. Asexual and sexual stages, and infections with different malaria parasite species are analysed. Across all states of Nigeria, there was a positive correlation between mean asexual parasite density within infected individuals and prevalence of infection in the community (Spearman's rho = 0.39, P = 0.02). Asexual parasite densities were highest in the northern geopolitical zones (geometric means > 2000 µL-1), extending the evidence of exceptionally high infection burden in many areas. Sexual parasite prevalence in each state was highly correlated with asexual parasite prevalence (Spearman's rho = 0.70, P < 0.001), although sexual parasite densities were low (geometric means < 100 µL-1 in all zones). Infants had lower parasite densities than children above 1 year of age, but there were no differences between male and female children. Most infections were of P. falciparum, which had higher asexual densities but lower sexual parasite densities than P. malariae or P. ovale mono-infections. However, mixed species infections had the highest asexual parasite densities. It is recommended that future large surveys in high burden countries measure parasite densities as well as developmental stages and species, to improve the quality of malaria epidemiology and tracking of future changes.


Assuntos
Coinfecção , Malária Falciparum , Malária , Parasitos , Criança , Lactente , Animais , Humanos , Masculino , Feminino , Microscopia , Nigéria/epidemiologia , Malária/epidemiologia , Malária/parasitologia , Malária Falciparum/parasitologia , Prevalência , Plasmodium falciparum
20.
Ann Fam Med ; 21(1): 11-18, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36690486

RESUMO

BACKGROUND: Urinary tract infection (UTI) symptoms are common in primary care, but antibiotics are appropriate only when an infection is present. Urine culture is the reference standard test for infection, but results take >1 day. A machine learning predictor of urine cultures showed high accuracy for an emergency department (ED) population but required urine microscopy features that are not routinely available in primary care (the NeedMicro classifier). METHODS: We redesigned a classifier (NoMicro) that does not depend on urine microscopy and retrospectively validated it internally (ED data set) and externally (on a newly curated primary care [PC] data set) using a multicenter approach including 80,387 (ED) and 472 (PC) adults. We constructed machine learning models using extreme gradient boosting (XGBoost), artificial neural networks, and random forests (RFs). The primary outcome was pathogenic urine culture growing ≥100,000 colony forming units. Predictor variables included age; gender; dipstick urinalysis nitrites, leukocytes, clarity, glucose, protein, and blood; dysuria; abdominal pain; and history of UTI. RESULTS: Removal of microscopy features did not severely compromise performance under internal validation: NoMicro/XGBoost receiver operating characteristic area under the curve (ROC-AUC) 0.86 (95% CI, 0.86-0.87) vs NeedMicro 0.88 (95% CI, 0.87-0.88). Excellent performance in external (PC) validation was also observed: NoMicro/RF ROC-AUC 0.85 (95% CI, 0.81-0.89). Retrospective simulation suggested that NoMicro/RF can be used to safely withhold antibiotics for low-risk patients, thereby avoiding antibiotic overuse. CONCLUSIONS: The NoMicro classifier appears appropriate for PC. Prospective trials to adjudicate the balance of benefits and harms of using the NoMicro classifier are appropriate.


Assuntos
Urinálise , Infecções Urinárias , Adulto , Humanos , Estudos Retrospectivos , Estudos Prospectivos , Microscopia , Infecções Urinárias/diagnóstico , Antibacterianos , Aprendizado de Máquina , Atenção Primária à Saúde/métodos
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