Detection of Bacteria in Bladder Mucosa of Adult Females

PURPOSE

Interstitial cystitis/bladder pain syndrome is a chronic urological condition diagnosed in nearly 8 million females in the United States. Whether urinary microbiota play an etiological role remains controversial. Most studies assessed the microbiota of interstitial cystitis/bladder pain syndrome patients with voided or catheterized urine as a proxy for bladder urothelium; however, urine may not be a true reflection of the bladder microbiota. Bladder biopsy tissue may provide a more accurate, and thus more clinically relevant, picture of bladder microbiota.

MATERIALS AND METHODS

Bladder biopsy tissues were obtained from: (1) 30 females with interstitial cystitis/bladder pain syndrome (18-80 years old) via cystoscopically guided cold-cup biopsy following therapeutic bladder hydrodistention, and (2) 10 non-interstitial cystitis/bladder pain syndrome females undergoing pelvic organ prolapse repair. To detect bacteria, technical duplicates of each RNAlater-preserved biopsy were subjected to 16S rRNA gene sequencing. To visualize bacteria, paraformaldehyde-fixed, paraffin-embedded biopsies were subjected to a combined multiplexed fluorescence in situ hybridization and fluorescence immunohistochemistry assay and confocal microscopy.

RESULTS

Bacteria were detected by 16S rRNA gene sequencing in at least 1 technical duplicate of most biopsies. The most abundant genus was Staphylococcus, followed by Lactobacillus; Escherichia was common but not abundant. There was no significant difference between interstitial cystitis/bladder pain syndrome patients and controls (P > .05). Combined fluorescence in situ hybridization and immunohistochemistry reproducibly detected 16S rRNA in epithelial cells and shed cells in the urothelium and lesioned areas and capillary walls in the lamina propria of human bladder biopsy tissue.

CONCLUSIONS

We conclude that urothelial and urinary microbiota are similar but not identical in adult females.

Biocontrol of Meloidogyne spp. in Solanum lycopersicum using a dual combination of Bacillus strains

Root-knot nematodes (RKNs, Meloidogyne spp.) are obligate plant parasites that constitute a significant pest for agriculture worldwide. They penetrate the plant roots, reducing the uptake of water and nutrients, causing a significant impact on crop yield. One alternative on focus now for nematode management is biological control. Rhizobacteria within the Bacillus genus show multiple modes of action against plant-parasitic nematodes (PPNs) that can act alone or in combination. In this context, we evaluated a dual-strain bacteria combination (B. paralicheniformi FMCH001 and B. subtilis FMCH002) to reduce nematode infection in tomato plants. We evaluated mortality of larvae from Meloidogyne javanica in vitro, as well as eggs hatching after the treatment. Atraction, penetration, establishment, and reproduction assays in vitro or in pots in tomato plants infected with M. javanica and treated/ untreated with the dual-strain bacteria combination were also performed. Additionally, morphometric parameters comparing giant cells size from galls of treated and untreated plants by using confocal microscopy were also measured. The results showed that this combination of strains has nematicidal properties in the pre-infection phase by decreasing the egg-hatching, juvenile survival, and attractiveness to the roots. Furthermore, nematode establishment, gall formation, and, remarkably, giant cell development was severely impaired after the bacterial treatment, suggesting interference with morphogenetic mechanisms induced by the nematode during GCs development within the plant. Nematode reproduction in tomato plants was reduced independently of the application mode in soil, before or after bacterial treatment. The dual-strain combination was also effective against other PPNs (i.e. Pratylenchus spp.) and in different crops (soybean). Therefore, combining B. paralicheniformis FMCH001 and B. subtilis FMCH002 is an efficient agent for the biological control of Meloidogyne spp. by interfering with different stages of the nematode cycle as a result of multiple modes of action.

Dermoscopy and reflectance confocal microscopy-augmented characterization of pigmented micro-basal cell carcinoma (less than 2 mm diameter)

BACKGROUND

Basal cell carcinoma (BCC) is the most common skin cancer, accounting for approximately 80% of nonmelanoma skin cancer diagnoses each year. Among other factors, the staging of BCC is influenced by its measured diameter. Stage 1 BCC is defined as a lesion measuring 2 cm across or less. Of note, there have been increasing publications reporting features of "small-sized" BCCs, which can present smaller than 1 mm. However, few of these studies have characterized features of pigmented small-sized BCC. The application of in-vivo imaging such as dermoscopy and reflectance confocal microscopy (RCM) allows for the non-invasive distinction of these lesions from benign and malignant melanocytic neoplasms, thereby reducing unnecessary biopsies.

METHODS

Within one year, three patients presented to Oregon Health and Science University's dermatology clinic with pigmented lesions of concern measuring less than 2 mm that were histologically confirmed as pigmented BCC. We sought to characterize the features of these lesions in a case series with the non-invasive imaging modalities of dermoscopy and RCM.

RESULTS

All cases presented clinically as a small, brown, macule on the face. Each of the three cases exhibited differing features on dermoscopy. With the application of RCM, we were able to visualize characteristic BCC features, prompting removal by shave biopsy.

CONCLUSION

To our knowledge, no other study has reported dermoscopic and RCM features of a cohort of pigmented BCCs 2 mm in diameter or smaller. We propose to define BCCs of this size as micro-BCCs. The variability of dermoscopic findings observed in our study, combined with the small size of these pigmented lesions, shows the utility of RCM as a non-invasive diagnostic tool for pigmented micro-BCCs.

Flecainide induces a sustained countercurrent dependent effect on RyR2 in permeabilized WT ventricular myocytes but not in intact cells

Background and purpose: While flecainide is now an accepted treatment for arrhythmias associated with catecholaminergic polymorphic ventricular tachycardia (CPVT), its mechanism of action remains controversial. In studies on myocytes from CPVT mice, inhibition of proarrhythmic Ca²⁺ waves was initially attributed to a novel action on the type-2 ryanodine receptor (RyR2). However, subsequent work on wild type (WT) myocytes questioned the conclusion that flecainide has a direct action on RyR2. In the present study, the effects of flecainide were compared in intact and permeabilized WT myocytes. Experimental approach: Intracellular Ca²⁺ was measured using confocal microscopy in intact or saponin permeabilized adult rat ventricular myocytes (ARVM). In some experiments on permeabilized cells, flecainide was studied following partial inhibition of the sarcoplasmic reticulum (SR) counter-current. Key results: Flecainide induced sustained changes Ca²⁺ sparks and waves in permeabilized ARVM, which were comparable to those reported in intact or permeabilized myocytes from CPVT mice. However, a relatively high level of flecainide (25 μM) was required to induce these effects. Inhibition of the SR counter-current potentiated the effects of flecainide on SR Ca²⁺ waves. In intact field stimulated ARVM, prolonged exposure to 15 μM flecainide decreased wave frequency but RyR2 dependent effects on Ca²⁺ sparks were absent; higher drug concentrations blocked field stimulation, consistent with inhibition of Nav1.5. Conclusions and implications: In intact ARVM, the absence of effects on Ca²⁺ sparks suggests that the intracellular flecainide concentration was insufficient to influence RyR2. Wave inhibition in intact ARVM may reflect secondary effects of Nav1.5 inhibition. Potentiation of flecainide's action by counter-current inhibition can be explained if transient polarization of the SR membrane during SR Ca²⁺ release facilitates its action on RyR2.

Combining mKate2-Kv1.3 Channel and Atto488-Hongotoxin for the Studies of Peptide Pore Blockers on Living Eukaryotic Cells

The voltage-gated potassium Kv1.3 channel is an essential component of vital cellular processes which is also involved in the pathogenesis of some autoimmune, neuroinflammatory and oncological diseases. Pore blockers of the Kv1.3 channel are considered as potential drugs and are used to study Kv1 channels' structure and functions. Screening and study of the blockers require the assessment of their ability to bind the channel. Expanding the variety of methods used for this, we report on the development of the fluorescent competitive binding assay for measuring affinities of pore blockers to Kv1.3 at the membrane of mammalian cells. The assay constituents are hongotoxin 1 conjugated with Atto488, fluorescent mKate2-tagged Kv1.3 channel, which was designed to improve membrane expression of the channel in mammalian cells, confocal microscopy, and a special protocol of image processing. The assay is implemented in the "mix and measure", format and allows the screening of Kv1.3 blockers, such as peptide toxins, that bind to the extracellular vestibule of the K⁺-conducting pore, and analyzing their affinity.

Reflectance Confocal Microscopy in the Diagnosis of Onychomycosis: A Systematic Review

Accurately diagnosing onychomycosis is vital, as therapy is time-consuming and accompanied by multiple adverse effects. Reflectance confocal microscopy (RCM), in contrast to traditional mycological testing, is a noninvasive, point-of-care tool that can rapidly identify fungal lesions. This systematic review aims to understand the utility of RCM in evaluating onychomycosis and follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A systematic search of four databases was conducted. A total of five articles-three prospective cohort studies and two case reports-which reported RCM findings in nails clinically suspicious for onychomycosis were analyzed. Fungal hyphae or spores were visualized on RCM in 67 (81.7%) of the 82 mycologically confirmed cases of onychomycosis. Terms used to describe hyphae included bright, linear, lengthy, thready-like, branching and filamentous. Spores were described as bright, roundish structures with high reflection. The three cohort studies demonstrated RCM had a sensitivity of 52.9-91.7, a specificity of 57.58-90.2%, a positive predictive value of 61.1-88.6% and a negative predictive value of 68.0-90.5%. In conclusion, existing studies demonstrate how RCM can assist the diagnosis of onychomycosis at the bedside. Larger studies incorporating multiple testing modalities to confirm the diagnosis of onychomycosis are warranted to further explore the diagnostic utility of RCM.

Influence of dual rinse irrigation on dentinal penetration of a bioceramic root canal sealer: A Conofocal microscopic Analysis

To evaluate the sealer penetration after applying dual rinse irrigant in comparison with sodium hypochlorite and 17% EDTA. Mandibular premolars were prepared by ProTaper Next and irrigated with NaOCl, NaOCl/Dual Rinse or NaOCl/EDTA and then obturated with a single-cone technique and bioceramic-based. Samples were observed using confocal laser microscopy, and the maximum depth of penetration was measured, as well as the percentage of sealer coating the canal wall and the penetration area of the sealer. One-way anova was used, followed by Tukey post hoc test. Sealer penetration area displayed a statistically significant difference between the tested groups (P < 0.05), and the highest percentage of sealer coating the canal wall and the greatest depth of sealer penetration were found in Group (NaOCl/Dual Rinse). Group (NaOCl/Dual Rinse) displayed better sealer penetration inside the dentinal tubules than Group (NaOCl/EDTA), while Group (NaOCl) showed the lowest sealer penetration.

Defining an Optimal Sample Size for Corneal Epithelial Immune Cell Analysis Using in vivo Confocal Microscopy Images

Purpose

In vivo confocal microscopy (IVCM) images are frequently used to quantify corneal epithelial immune cell (IC) density in clinical studies. There is currently limited evidence to inform the selection of a representative image sample size to yield a reliable IC density estimate, and arbitrary numbers of images are often used. The primary aim of this study was to determine the number of randomly selected, unique IVCM images required to achieve an acceptable level of accuracy when quantifying epithelial IC density, in both the central and peripheral cornea. The secondary aim was to evaluate the consistency and precision of an image selection approach where corneal epithelial IC density was quantified from "three representative images" selected independently by three experienced observers.

Methods

All combinations of two to 15 non-overlapping IVCM images were used for deriving IC density estimates, for both the central and peripheral cornea, in 20 healthy participants; the density value from averaging quantifications in the 16 images was defined as the "true mean". IC density estimates were compared with the true mean in each corneal region using a mean ratio. Intraclass correlation coefficients (ICCs) were used to evaluate the consistency of the mean ratios of IC density estimates derived from the method involving the manual selection of "three representative images" by the observers. The precision of the IC density estimates was compared to a scenario involving three randomly selected images.

Results

A total of 12 randomly selected, non-overlapping IVCM images were found to be required to produce a corneal epithelial IC density estimate that was within 30% of the true mean, 95% of the time, for the central cornea; seven such images produced an equivalent level of precision in the peripheral cornea. Mean ratios of corneal IC density estimates derived from "three representative images" methods had poor consistency between observers (ICC estimates <0.5) and similar levels of precision when compared with using three randomly selected images (p > 0.05 for all comparisons), in both the central and peripheral cornea.

Conclusions

Data presented in this study can inform image selection methods, and the sample size required for a preferred level of accuracy, when quantifying IC densities in the central and peripheral corneal epithelium using IVCM images.

Contemporary Concise Review 2021: Pulmonary nodules from detection to intervention

The US Preventive Task Force (USPSTF) has updated screening criteria by expanding age range and reducing smoking history required for eligibility; the International Lung Screen Trial (ILST) data have shown that PLCOM2012 performs better for eligibility than USPSTF criteria. Screening adherence is low (4%-6% of potential eligible candidates in the United States) and depends upon multiple system and patient/candidate-related factors. Smoking cessation in lung cancer improves survival (past prospective trial data, updated meta-analysis data); smoking cessation is an essential component of lung cancer screening. Circulating biomarkers are emerging to optimize screening and early diagnosis. COVID-19 continues to affect lung cancer treatment and screening through delays and disruptions; specific operational challenges need to be met. Over 70% of suspected malignant lesions develop in the periphery of the lungs. Bronchoscopic navigational techniques have been steadily improving to allow greater accuracy with target lesion approximation and therefore diagnostic yield. Fibre-based imaging techniques provide real-time microscopic tumour visualization, with potential diagnostic benefits. With significant advances in peripheral lung cancer localization, bronchoscopically delivered ablative therapies are an emerging field in limited stage primary and oligometastatic disease. In advanced stage lung cancer, small-volume samples acquired through bronchoscopic techniques yield material of sufficient quantity and quality to support clinically relevant biomarker assessment.

High Resolution Fluorescence Lifetime Maps from Minimal Photon Counts

Fluorescence lifetime imaging microscopy (FLIM) may reveal subcellular spatial lifetime maps of key molecular species. Yet, such a quantitative picture of life necessarily demands high photon budgets at every pixel under the current analysis paradigm, thereby increasing acquisition time and photodamage to the sample. Motivated by recent developments in computational statistics, we provide a direct means to update our knowledge of the lifetime maps of species of different lifetimes from direct photon arrivals, while accounting for experimental features such as arbitrary forms of the instrument response function (IRF) and exploiting information from empty laser pulses not resulting in photon detection. Our ability to construct lifetime maps holds for arbitrary lifetimes, from short lifetimes (comparable to the IRF) to lifetimes exceeding interpulse times. As our method is highly data efficient, for the same amount of data normally used to determine lifetimes and photon ratios, working within the Bayesian paradigm, we report direct blind unmixing of lifetimes with subnanosecond resolution and subpixel spatial resolution using standard raster scan FLIM images. We demonstrate our method using a wide range of simulated and experimental data.

Confocal reflectance microscopy for metal and lipid nanoparticle visualization in the brain

Background: A requirement for nanoparticle (NP) research is visualization of particles within cells and tissues. Limitations of electron microscopy and low yields of NP fluorescent tagging warrant the identification of alternative imaging techniques. Method: Confocal reflectance microscopy (CRM) in combination with fluorescence imaging was assessed for visualizing rhodamine B-conjugated silver and fluorescein isothiocyanate-conjugated lipid core-stearylamine NP uptake in vitro and in vivo. Results: CRM successfully identified cellular uptake and blood-brain barrier penetration of NPs owing to their distinguishing refractive indices. NP-dependent reflectance signals in vitro were dose and incubation time dependent. Finally, CRM facilitated the distinction between nonspecific fluorescence signals and NPs. Conclusion: These findings demonstrate the value of CRM for NP visualization in tissues, which can be performed with a standard confocal microscope.

Ex vivo fluorescent confocal microscopy images of oral mucosa: Tissue atlas and evaluation of the learning curve

Ex vivo fluorescence confocal microscopy (FCM) is a developing tool providing rapid digital imaging of fresh tissue utilizing high-resolution optical sectioning that highly corresponds with conventional hmatoxylin and eosin (H&E)-stained slides. A very little data on oral mucosa lesions exist currently. The present work aimed to create an image atlas of benign and malignant oral tissues and compare them to the corresponding histopathology. Furthermore, we aimed to evaluate the learning curve for confocal image interpretation. From 50 samples obtained from the oral mucosa, including oral squamous cell carcinoma (OSCC), dysplasia, and healthy oral tissue, ex vivo FCM images and corresponding H&E slides were created and collected into a tissue atlas. Additionally, two experts were asked to analyze the images to assess the learning curve. Ex vivo FCM images revealed high comparability with histopathological images. Tissues including OSCC, dysplasia, and normal oral mucosa were implemented in the image atlas to provide the diagnostic fundament for pathologists and surgeons; the learning curve was short. Future studies on this topic will be advantageous for the development of artificial intelligence-based diagnostic approaches. The current work provides a novel set of data that are structured as an atlas of common pathologies of the mucosa to enhance the existing knowledge and material on confocal images.

Determinative Structural Features Identified With Probe-based Confocal Endomicroscopy for the Accurate Diagnosis of Gallbladder Malignancy

BACKGROUND

Probe-based confocal laser endomicroscopy (pCLE) can visualize microscopic structures at high resolution but has not yet yielded definitive diagnostic features of gallbladder malignancy, as opposed to benign changes.

PATIENTS AND METHODS

A total of 73 patients had their gallbladder evaluated with pCLE performed on resected benign and malignant gallbladder surgical specimens, which were sprayed with fluorescein. Malignant and benign features of pCLE findings were identified on the basis of Miami and Paris Classifications. Standard histopathological diagnoses and individual patient pCLE findings of gallbladder lesions were correlated.

RESULTS

Of the 73 consecutive patients that had their gallbladder evaluated ex vivo with pCLE, 11 were identified with gallbladder malignancy. pCLE identified features of gallbladders examined ex vivo, including the presence of thick dark bands and dark clumps, which together correlated with histopathologically-determined biliary malignancy at 100% sensitivity. Thick white bands and visualized epithelium, also identified with pCLE, together correlated with histopathologically-determined malignancy at 100% specificity.

CONCLUSION

pCLE can be used for real-time differentiation of cancerous/non-cancerous regions in the gallbladder using the diagnostic criteria identified in the present study.

Single Particle Automated Raman Trapping Analysis of Breast Cancer Cell-Derived Extracellular Vesicles as Cancer Biomarkers

Extracellular vesicles (EVs) secreted by cancer cells provide an important insight into cancer biology and could be leveraged to enhance diagnostics and disease monitoring. This paper details a high-throughput label-free extracellular vesicle analysis approach to study fundamental EV biology, toward diagnosis and monitoring of cancer in a minimally invasive manner and with the elimination of interpreter bias. We present the next generation of our single particle automated Raman trapping analysis─SPARTA─system through the development of a dedicated standalone device optimized for single particle analysis of EVs. Our visualization approach, dubbed dimensional reduction analysis (DRA), presents a convenient and comprehensive method of comparing multiple EV spectra. We demonstrate that the dedicated SPARTA system can differentiate between cancer and noncancer EVs with a high degree of sensitivity and specificity (&gt;95% for both). We further show that the predictive ability of our approach is consistent across multiple EV isolations from the same cell types. Detailed modeling reveals accurate classification between EVs derived from various closely related breast cancer subtypes, further supporting the utility of our SPARTA-based approach for detailed EV profiling.

Hybrid layer formation and bond strength to dentin impregnated with endodontic sealer after cleaning protocols

Aims:

This study evaluated the hybrid layer formation and bond strength of two adhesive systems, Scotchbond Universal (U) or Adper Scotchbond Multi Purpose (M), after cleaning protocols using ethanol (E) or xylol (X), to dentin impregnated with an epoxy-resin based endodontic sealer.

Settings and Design:

The study design was an Experimental in vitro study.

Methodology:

One hundred bovine dentin specimens were randomly allocated into five groups (n = 10): Computed tomography (CT) (control): Only acid etching + M; E+U; X+U; E+M. After the specimen preparation, images were obtained using confocal laser scanning microscopy to evaluate the hybrid layer formation. For microshear bond strength test, the dentin specimens were included in polyvinyl chloride tubes and four resin composite cylinders were placed on the surface. The analysis was performed 24 h after storage.

Statistical Analysis Used:

For parametric and nonparametric data, analysis of variance followed by Tukey test and Kruskal–Wallis, followed by Dunn test were, respectively, used at a significance level of 5%.

Results:

Regarding hybrid layer formation, all experimental groups were similar to each other (P > 0.05). However, CT showed higher hybrid layer formation than other groups (P < 0.05), except in relation to X+M (P > 0.05). Bond strength was statistically similar among all groups (P > 0.05).

Conclusions:

Hybrid layer formation in dentin impregnated with epoxy resin-based sealer and submitted to different cleaning protocols was similar to the control group only for X+M. No differences were found among the experimental groups. Regarding the bond strength, no effect was observed for any group.

Optimization of Advanced Live-Cell Imaging through Red/Near-Infrared Dye Labeling and Fluorescence Lifetime-Based Strategies

Fluorescence microscopy is essential for a detailed understanding of cellular processes; however, live-cell preservation during imaging is a matter of debate. In this study, we proposed a guide to optimize advanced light microscopy approaches by reducing light exposure through fluorescence lifetime (τ) exploitation of red/near-infrared dyes. Firstly, we characterized key instrumental elements which revealed that red/near-infrared laser lines with an 86x (Numerical Aperture (NA) = 1.2, water immersion) objective allowed high transmission of fluorescence signals, low irradiance and super-resolution. As a combination of two technologies, i.e., vacuum tubes (e.g., photomultiplier) and semiconductor microelectronics (e.g., avalanche photodiode), type S, X and R of hybrid detectors (HyD-S, HyD-X and HyD-R) were particularly adapted for red/near-infrared photon counting and τ separation. Secondly, we tested and compared lifetime-based imaging including coarse τ separation for confocal microscopy, fitting and phasor plot analysis for fluorescence lifetime microscopy (FLIM), and lifetimes weighting for enhanced stimulated emission depletion (STED) nanoscopy, in light of red/near-infrared multiplexing. Mainly, we showed that the choice of appropriate imaging approach may depend on fluorochrome number, together with their spectral/lifetime characteristics and STED compatibility. Photon-counting mode and sensitivity of HyDs together with phasor plot analysis of fluorescence lifetimes enabled the flexible and fast imaging of multi-labeled living H28 cells. Therefore, a combination of red/near-infrared dyes labeling with lifetime-based strategies offers new perspectives for live-cell imaging by enhancing sample preservation through acquisition time and light exposure reduction.

Improving dermal level images from reflectance confocal microscopy using wavelet-based transformations and adaptive histogram equalization

OBJECTIVES

Reflectance confocal microscopy (RCM) generates scalar image data from serial depths in the skin, allowing in vivo examination of cellular features. The maximum imaging depth of RCM is approximately 250 µm, to the papillary dermis, or upper reticular dermis. Frequently, important diagnostic features are present in the dermis, hence improved visualization of deeper levels is advantageous.

METHODS

Low contrast and noise in dermal images were improved by employing a combination of wavelet-based transformations and contrast-limited adaptive histogram equalization.

RESULTS

Preserved details, noise reduction, increased contrast, and feature enhancement were observed in the resulting processed images.

CONCLUSIONS

Complex and combined wavelet-based enhancement approaches for dermal level images yielded reconstructions of higher quality than less sophisticated histogram-based strategies. Image optimization may improve the diagnostic accuracy of RCM, especially for entities with dermal findings.

Encoding of cutaneous stimuli by lamina I projection neurons

ABSTRACT

Lamina I of the dorsal horn, together with its main output pathway, lamina I projection neurons, has long been implicated in the processing of nociceptive stimuli, as well as the development of chronic pain conditions. However, the study of lamina I projection neurons is hampered by technical challenges, including the low throughput and selection biases of traditional electrophysiological techniques. Here we report on a technique that uses anatomical labelling strategies and in vivo imaging to simultaneously study a network of lamina I projection neurons in response to electrical and natural stimuli. Although we were able to confirm the nociceptive involvement of this group of cells, we also describe an unexpected preference for innocuous cooling stimuli. We were able to characterize the thermal responsiveness of these cells in detail and found cooling responses decline when exposed to stable cold temperatures maintained for more than a few seconds, as well as to encode the intensity of the end temperature, while heating responses showed an unexpected reliance on adaptation temperatures.

Multimodal 3D photoacoustic remote sensing and confocal fluorescence microscopy imaging

SIGNIFICANCE

Complementary absorption and fluorescence contrast could prove useful for a wide range of biomedical applications. However, current absorption-based photoacoustic microscopy systems require the ultrasound transducers to physically touch the samples, thereby increasing contamination and limiting strong optical focusing in reflection mode.

AIM

We sought to develop an all-optical system for imaging cells and tissues using the three combined imaging modalities: photoacoustic remote sensing (PARS), epifluorescence, and confocal laser scanning microscopy (CLSM).

APPROACH

A PARS subsystem with ultraviolet excitation was used to obtain label-free absorption-contrast images of nucleic acids in ex vivo tissue samples. Co-integrated epifluorescence and CLSM subsystems were used to verify the 2D and 3D nuclei distribution.

RESULTS

Complementary absorption and fluorescence contrast were demonstrated in phantom imaging experiments and subsequent cell and tissue imaging experiments. Lateral and axial resolution of ultraviolet-PARS (UV-PARS) is shown to be 0.39 and 1.6  μm, respectively, with 266-nm light. CLSM lateral and axial resolution was measured as 0.97 and 2.0  μm, respectively. This resolution is sufficient to image individual cell layers with fine optical sectioning. UV-PARS images of cell nuclei are validated in thick tissue using CLSM.

CONCLUSIONS

Multimodal absorption and fluorescence contrast are obtained with a non-contact all-optical microscopy system for the first time and utilized to obtain images of cells and tissues with subcellular resolution.

Guideline for in vivo assessment of adherent and rolling leukocytes in human skin microvasculature via reflectance confocal videomicroscopy

OBJECTIVE

To develop a guideline that reliably identifies cutaneous adherent and rolling leukocytes from mimicking scenarios via in vivo reflectance confocal videomicroscopy.

METHODS

We used a clinical reflectance confocal microscope, the VivaScope 1500, to acquire 1522 videos of the upper dermal microcirculation from 12 healthy subjects and 60 patients after allogeneic hematopoietic cell transplantation. Blinded to clinical information, two trained raters independently counted the number of adherent and rolling leukocytes in 88 videos. Based on discrepancies in the initial assessments, we developed a guideline to identify both types of leukocyte-endothelial interactions via a modified Delphi method (without anonymity). To test the guideline's ability to improve the inter-rater reliability, the two raters assessed the remaining 1434 videos by using the guideline.

RESULTS

We demonstrate a guideline that consists of definitions, a step-by-step flowchart, and corresponding visuals of adherent and rolling leukocytes and mimicking scenarios. The guideline improved the inter-rater reliability of the manual assessment of both interactions. The intraclass correlation coefficient (ICC) of adherent leukocyte counts increased from 0.056 (95% confidence interval: 0-0.236, n = 88 videos, N = 10 subjects) to 0.791 (0.770-0.809, n = 1434, N = 67). The ICC of rolling leukocyte counts increased from 0.385 (0.191-0.550, n = 88, N = 10) to 0.626 (0.593-0.657, n = 1434, N = 67). Intra-rater ICC post-guideline was 0.953 (0.886-0.981, n = 20, N = 12) and 0.956 (0.894-0.983, n = 20, N = 12) for adherent and rolling, respectively.

CONCLUSION

The guideline aids in the manual identification of adherent and rolling leukocytes via in vivo reflectance confocal videomicroscopy.

Needle-based confocal laser endomicroscopy for diagnosis of pancreatic cystic lesions: a meta-analysis

BACKGROUND AND AIM

The role of needle-based confocal laser endomicroscopy (nCLE) in the diagnosis of pancreatic cystic lesions (PCLs) remains controversial. This study aimed to systematically evaluate the diagnostic accuracy and adverse effects of nCLE in the detection of pathological subtypes in patients with PCLs.

MATERIAL AND METHODS

We conducted a comprehensive literature search using MEDLINE, EMBASE, and Cochrane for identifying studies that reported the use of nCLE for PCLs diagnosis (dated prior to 10 October 2020). Studies with a sample size >10 were included. We used the QUADAS-2 criteria for quality evaluation. We first extracted the diagnostic rates and the information on adverse events (AEs) from the studies; then used STATA15.0 to calculate the variables, draw forest plots and summary receiver operating characteristic (SROC) curves; and finally, we completed subgroup analyses to explore the heterogeneity.

RESULTS

Overall, 299 article titles were identified after an initial search, and ten studies with 547 individuals with PCLs were included in the analysis. The pooled sensitivity, specificity, positive likelihood ratio, and pooled negative likelihood ratio of nCLE in detecting gastric disorders were 90%, 96%, 20.4, and 0.11, respectively. The pooled sensitivity and specificity showed a substantial heterogeneity. An ROC curve was constructed with an area under the curve (AUC) of 0.94. The overall AEs rate of pancreatitis was 2.7%.

CONCLUSIONS

We showed that nCLE had a relatively high sensitivity and specificity for diagnosing PCLs with a relatively low rate of AEs occurring. We suggest that nCLE has good diagnostic accuracy for PCLs.

QUAREP-LiMi: A community-driven initiative to establish guidelines for quality assessment and reproducibility for instruments and images in light microscopy

A modern day light microscope has evolved from a tool devoted to making primarily empirical observations to what is now a sophisticated , quantitative device that is an integral part of both physical and life science research. Nowadays, microscopes are found in nearly every experimental laboratory. However, despite their prevalent use in capturing and quantifying scientific phenomena, neither a thorough understanding of the principles underlying quantitative imaging techniques nor appropriate knowledge of how to calibrate, operate and maintain microscopes can be taken for granted. This is clearly demonstrated by the well-documented and widespread difficulties that are routinely encountered in evaluating acquired data and reproducing scientific experiments. Indeed, studies have shown that more than 70% of researchers have tried and failed to repeat another scientist's experiments, while more than half have even failed to reproduce their own experiments. One factor behind the reproducibility crisis of experiments published in scientific journals is the frequent underreporting of imaging methods caused by a lack of awareness and/or a lack of knowledge of the applied technique. Whereas quality control procedures for some methods used in biomedical research, such as genomics (e.g. DNA sequencing, RNA-seq) or cytometry, have been introduced (e.g. ENCODE), this issue has not been tackled for optical microscopy instrumentation and images. Although many calibration standards and protocols have been published, there is a lack of awareness and agreement on common standards and guidelines for quality assessment and reproducibility. In April 2020, the QUality Assessment and REProducibility for instruments and images in Light Microscopy (QUAREP-LiMi) initiative was formed. This initiative comprises imaging scientists from academia and industry who share a common interest in achieving a better understanding of the performance and limitations of microscopes and improved quality control (QC) in light microscopy. The ultimate goal of the QUAREP-LiMi initiative is to establish a set of common QC standards, guidelines, metadata models and tools, including detailed protocols, with the ultimate aim of improving reproducible advances in scientific research. This White Paper (1) summarizes the major obstacles identified in the field that motivated the launch of the QUAREP-LiMi initiative; (2) identifies the urgent need to address these obstacles in a grassroots manner, through a community of stakeholders including, researchers, imaging scientists, bioimage analysts, bioimage informatics developers, corporate partners, funding agencies, standards organizations, scientific publishers and observers of such; (3) outlines the current actions of the QUAREP-LiMi initiative and (4) proposes future steps that can be taken to improve the dissemination and acceptance of the proposed guidelines to manage QC. To summarize, the principal goal of the QUAREP-LiMi initiative is to improve the overall quality and reproducibility of light microscope image data by introducing broadly accepted standard practices and accurately captured image data metrics.

High Resolution, Deep Imaging Using Confocal Time-of-Flight Diffuse Optical Tomography

Light scattering by tissue severely limits how deep beneath the surface one can image, and the spatial resolution one can obtain from these images. Diffuse optical tomography (DOT) is one of the most powerful techniques for imaging deep within tissue - well beyond the conventional  ∼ 10-15 mean scattering lengths tolerated by ballistic imaging techniques such as confocal and two-photon microscopy. Unfortunately, existing DOT systems are limited, achieving only centimeter-scale resolution. Furthermore, they suffer from slow acquisition times and slow reconstruction speeds making real-time imaging infeasible. We show that time-of-flight diffuse optical tomography (ToF-DOT) and its confocal variant (CToF-DOT), by exploiting the photon travel time information, allow us to achieve millimeter spatial resolution in the highly scattered diffusion regime ( mean free paths). In addition, we demonstrate two additional innovations: focusing on confocal measurements, and multiplexing the illumination sources allow us to significantly reduce the measurement acquisition time. Finally, we rely on a novel convolutional approximation that allows us to develop a fast reconstruction algorithm, achieving a 100× speedup in reconstruction time compared to traditional DOT reconstruction techniques. Together, we believe that these technical advances serve as the first step towards real-time, millimeter resolution, deep tissue imaging using DOT.