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1.
J Contemp Dent Pract ; 22(6): 691-702, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34393129

RESUMO

AIM: Odontogenic tumors (OTs) and bone lesions of the oral cavity present diverse histological features and varying clinical behavior that makes predicting their biologic behavior difficult. The research undertaken in the current study aims to predict the biological behavior of oral hyalinizing odontogenic and bone lesions (OHO-BL) for the first time by employing four differential stains with clinicopathologic correlation. MATERIALS AND METHODS: The study was performed on retrospectively diagnosed formalin-fixed paraffin-embedded cases of OTs (n = 53) and bone lesions (n = 10). The severity of hyalinization (SOH) was assessed from stained tissue sections. Polarizing microscopy was used to analyze hyalinization in tissues stained with differential special stains, namely periodic acid-Schiff (PAS), Safranin-O, Alcian Blue, and Picrosirius red. SOH was also analyzed for possible correlation with recurrence and clinicopathologic correlation in OHO-BL. RESULTS: Intense staining was observed with PAS, Alcian Blue, and Safranin-O in OTs with increased SOH with a statistical significance. Polarizing greenish yellow color correlated significantly with the recurrence potential of the OT group. Recurrence in individual lesions of the OT group showed a statistically significant association with SOH. Such individual correlation was not observed in bone diseases. CONCLUSION: PAS, Alcian Blue, Safranin-O, and Picrosirius red are reliable stains to assess hyalinization in OHO-BL. Picrosirius red-polarizing microscopy is a dependable tool for identifying recurrent odontogenic lesions. CLINICAL SIGNIFICANCE: SOH can be considered a histological predictor of aggressive biologic behavior in oral hyalinizing odontogenic lesions that can enable the surgeon to arrive at an appropriate management protocol.


Assuntos
Doenças Ósseas , Tumores Odontogênicos , Corantes , Humanos , Microscopia de Polarização , Recidiva Local de Neoplasia , Estudos Retrospectivos , Coloração e Rotulagem
2.
Opt Lett ; 46(16): 4009-4012, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-34388798

RESUMO

In this Letter, we report a study on the effects of spatial filtering for a transmission Mueller matrix imaging system. A spatial filter (SF) is placed on the back Fourier plane of the imaging lens in a dual-rotating-retarders Mueller matrix imaging system to select photons within a certain scattering angle. The system is then applied to three types of human cancerous tissues. When imaging with a small-aperture SF, some polarimetry basis parameters show sharp changes in contrast in the cancerous regions. Monte Carlo simulations using a simple sphere-cylinder scattering model also show that spatial filtering of the scattered photons provides extra information on the size and shape of the scattering particles. The results indicate that spatial filtering enhances the capability of polarization imaging as a powerful tool for biomedical diagnosis.


Assuntos
Neoplasias , Fótons , Diagnóstico por Imagem , Humanos , Microscopia de Polarização , Método de Monte Carlo
3.
PLoS One ; 16(3): e0248068, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33735190

RESUMO

Collagen is an important component in maintaining structural integrity and functionality of tissues and is modulated in various biological processes. Its visualization and possible quantification using histopathological stains can be important for understanding disease progression or therapeutic response. Visualization of collagen fiber with the histological stain picrosirius red (PSR) is enhanced with polarized light and quantitative analysis is possible using circular polarizers. However, linear polarizers are more commonly available and easier to optically align. The objective of the present study is to demonstrate a novel image acquisition technique and analysis method using linearly polarized light. The proposed imaging technique is based on image acquisition at multiple slide rotation angles, which are co-registered to form a composite image used for quantitative analysis by pixel intensity or pixel counting. The technique was demonstrated on multiple human coronary samples with varying histopathologies and developed specifically to analyze cap collagen in atherosclerotic plaque. Pixel counting image analysis was found to be reproducible across serial tissue sections and across different users and sufficiently sensitive to detect differences in cap structural integrity that are likely relevant to prediction of rupture risk. The benefit of slide rotation angle under linear polarization to acquire images represents a feasible and practical implementation for expanding the general utility of PSR for quantitative analysis.


Assuntos
Compostos Azo , Colágeno/análise , Vasos Coronários/patologia , Microscopia de Polarização , Placa Aterosclerótica/patologia , Humanos , Coloração e Rotulagem
4.
Lasers Surg Med ; 53(7): 968-977, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33442896

RESUMO

BACKGROUND AND OBJECTIVES: Previous studies have shown that large changes in the diffuse reflectivity of caries lesions during drying with air can be used to assess lesion activity. The largest changes occur at short wavelength infrared (SWIR) wavelengths coincident with high water absorption. The strongest water absorption in the SWIR occurs at 1950 nm. In this study changes in the reflectivity of simulated lesions with varying degrees of remineralization was measured at 1500-2340 nm and at 1950 nm as the samples were dried with air. STUDY DESIGN/MATERIALS AND METHODS: Twenty bovine enamel surfaces each with five treatment windows were exposed to two demineralization/remineralization regimens to produce simulated lesions of varying depth, severity, and mineral gradients. An extended range tungsten-halogen lamp with a long pass filter (1500-2340 nm) and a broadband amplified spontaneous emission source centered near the peak of the water-absorption band at 1950-nm were used as light sources and an extended range InGaAs camera (1000-2340 nm) was used to acquire reflected light images as the samples were dried with air. Lesions were also assessed using digital microscopy, polarized light microscopy, optical coherence tomography, and transverse microradiography. RESULTS: Both wavelength ranges showed extremely high lesion contrast (>0.9) for all six lesion treatment windows in both models. The change in contrast (ΔI) was significantly higher for the 1950 nm broadband source for all the intact lesion windows compared with the 1500-2340 nm wavelength range. CONCLUSION: SWIR light at 1950 nm yields extremely high contrast of demineralization and appears to be the optimum wavelength for the assessment of lesion activity on tooth coronal surfaces. Lasers Surg. Med. 00:00-00, 2020. © 2020 Wiley Periodicals LLC.


Assuntos
Desmineralização do Dente , Animais , Bovinos , Esmalte Dentário/diagnóstico por imagem , Microscopia de Polarização , Espectroscopia de Luz Próxima ao Infravermelho , Tomografia de Coerência Óptica , Desmineralização do Dente/diagnóstico por imagem
5.
Cartilage ; 13(1_suppl): 1494S-1510S, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-32659115

RESUMO

OBJECTIVE: Evaluation of collagen orientation and arrangement in articular cartilage can improve our understanding of primary osteoarthritis (OA) progression and targeted therapies. Our goal was to determine if polarized light microscopy (PLM) for collagen organization is useful in identifying early primary OA features in comparison to current standard histopathological methods. DESIGN: Osteochondral specimens from 90 total knee arthroplasty patients with relatively preserved lateral femoral condyle were scored using (1) histological-histochemical grading system (HHGS); (2) Osteoarthritis Research Society International (OARSI); (3) PLM-Changoor system for repair cartilage, scores ranging between 0 (totally disorganized cartilage) and 5 (healthy adult cartilage); and (4) new PLM system for primary OA cartilage with superficial zone PLM (PLM-SZ) and deep zone PLM (PLM-DZ) scores, each ranging between 0 (healthy adult SZ and DZ collagen organization) and 4 (total loss of collagen organization). Serial sections were stained for collagen I and II antibodies. Spearman correlation coefficients (rs) were determined. RESULTS: The associations between: (1) PLM-Changoor and HHGS or OARSI were weak (rs = -0.36) or moderate (rs = -0.56); (2) PLM-SZ and HHGS or OARSI were moderate (rs = 0.46 or rs = 0.53); and (3) PLM-DZ and HHGS or OARSI were poor (rs = 0.31 or rs = 0.21), respectively. Specimens exhibiting early and mild OA (HHGS < 5 and OARSI < 8.6) had PLM-SZ and PLM-DZ scores between 0 and 4 and between 0 and 3, respectively, and indicated new histopathological features not currently considered by HHGS/OARSI. CONCLUSIONS: PLM was effective at identifying early SZ and DZ collagen alterations that were not evident in the traditional scoring systems. Incorporating PLM scores and/or additional HHGS/OARSI features can help improve characterization of early primary OA cartilage.


Assuntos
Cartilagem Articular , Colágeno , Microscopia de Polarização , Osteoartrite/patologia , Adulto , Progressão da Doença , Humanos , Imuno-Histoquímica
6.
Appl Opt ; 59(4): 1237-1248, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32225267

RESUMO

Analysis of spatial frequency of Mueller matrix (MM) images in the Fourier domain yields quantifying parameters of anisotropy in the stromal region in normal and precancerous tissue sections of human uterine cervix. The spatial frequencies of MM elements reveal reliable information of microscopic structural organization arising from the different orientations of collagen fibers in the connective tissue and their randomization with disease progression. Specifically, the local disorder generated in the normal periodic and regular structure of collagen during the growth of the cervical cancer finds characteristic manifestation in the Fourier spectrum of the selected Mueller matrix elements encoding the anisotropy effects through retardance and birefringence. In contrast, Fourier spectra of differential polarization gated images are limited to only one orientation of collagen. Fourier spectra of first row elements M11, M12, M13, and M14 and first column elements M11, M21, M31, and M41 discriminates cervical inter-epithelial neoplasia (CIN)-I from normal cervical tissue samples with 95%-100% sensitivity and specificity. FFT spectra of first and fourth row elements classify CIN-I and CIN-II grades of cervical cancerous tissues with 90%-100% sensitivity and 87%-100% specificity. Normal and CIN-II grade samples are successfully discriminated through Fourier spectra of every MM element while that of M31 element arises as the key classifier among normal, CIN-I, and CIN-II grades of cervical cancer with 100% sensitivity and specificity. These results demonstrate the promise of spatial frequency analysis of Mueller matrix images as a novel, to the best of our knowledge, approach for cancer/precancer detection.


Assuntos
Biomarcadores Tumorais/análise , Colo do Útero/diagnóstico por imagem , Colágeno/análise , Microscopia de Polarização/métodos , Neoplasias do Colo do Útero/diagnóstico por imagem , Anisotropia , Biomarcadores Tumorais/metabolismo , Técnicas Biossensoriais , Birrefringência , Colágeno/metabolismo , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Lasers , Conformação Molecular , Sensibilidade e Especificidade
7.
J Biomed Opt ; 25(1): 1-11, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31933331

RESUMO

Significance: Definitive diagnostics of many diseases is based on the histological analysis of thin tissue cuts with optical white light microscopy. Extra information on tissue structural properties obtained with polarized light would help the pathologist to improve the accuracy of his diagnosis.

Aim: We report on using Mueller matrix microscopy data, logarithmic decomposition, and polarized Monte Carlo (MC) modeling for qualitative and quantitative analysis of thin tissue cuts to extract the information on tissue microstructure that is not available with a conventional white light microscopy.

Approach: Unstained cuts of human skin equivalents were measured with a custom-built liquid-crystal-based Mueller microscope in transmission configuration. To interpret experimental data, we performed the simulations with a polarized MC algorithm for scattering anisotropic media. Several optical models of tissue (spherical scatterers within birefringent host medium, and combination of spherical and cylindrical scatterers within either isotropic or birefringent host medium) were tested.

Results: A set of rotation invariants for the logarithmic decomposition of a Mueller matrix was derived to rule out the impact of sample orientation. These invariants were calculated for both simulated and measured Mueller matrices of the dermal layer of skin equivalents. We demonstrated that only the simulations with a model combining both spherical and cylindrical scatterers within birefringent host medium reproduced the experimental trends in optical properties of the dermal layer (linear retardance, linear dichroism, and anisotropic linear depolarization) with layer thickness.

Conclusions: Our studies prove that Mueller polarimetry provides relevant information not only on a size of dominant scatterers (e.g., cell nuclei versus subwavelength organelles) but also on its shape (e.g., cells versus collagen fibers). The latter is directly related to the state of extracellular collagen matrix, which is often affected by early pathology. Hence, using polarimetric data can help to increase the accuracy of diagnosis.


Assuntos
Microscopia de Polarização/instrumentação , Imagem Óptica/métodos , Refratometria/métodos , Pele/diagnóstico por imagem , Humanos , Método de Monte Carlo , Fenômenos Ópticos , Imagens de Fantasmas , Espalhamento de Radiação
8.
J Vis Exp ; (150)2019 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-31475979

RESUMO

The optimal timing of intracytoplasmic sperm injection (ICSI) is of a serious concern for fertility programs because untimely sperm entry diminishes the egg's developmental competence. Presence of the first polar body (PB) together with the meiotic spindle indicates completion of the oocyte maturation and the egg's readiness for fertilization. In clinical practice, it is customary to assume that all oocytes displaying a PB are mature metaphase (MII) oocytes. However, PB extrusion precedes the formation of the bipolar MII spindle. This asynchrony makes the mere presence of PB an unreliable marker of oocyte maturity. Noninvasive spindle imaging using polarized light microscopy (PLM) allows quick and easy inspection of whether the PB-displaying oocyte actually reassembled a meiotic spindle prior to ICSI. Here, we present a standard protocol to perform human egg maturity assessment in the clinical laboratory. We also show how to optimize the time of ICSI with respect to the oocyte's developmental stage in order to prevent premature sperm injection of late-maturing oocytes. Using this approach, even immature oocytes extruding PB in vitro can be clinically utilized. Affirmation that MII spindle is present prior to sperm injection and individual adjustment of the time of ICSI is particularly important in poor prognosis in-vitro fertilization (IVF) cycles with a low number of oocytes available for fertilization.


Assuntos
Oócitos/citologia , Oogênese , Injeções de Esperma Intracitoplásmicas/métodos , Feminino , Humanos , Masculino , Metáfase , Microscopia de Polarização , Fuso Acromático
9.
Wound Repair Regen ; 27(6): 711-714, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31418977

RESUMO

Collagen fiber organization requires characterization in many biomedical applications, but it is difficult to objectively quantify in standard histology tissue sections. Quantitative polarized light imaging is a low-cost technique that allows for rapid measurement of collagen fiber orientation and thickness. In this study, we utilize a quantitative polarized light imaging system to characterize fiber orientation and thickness from wound sections. Full thickness skin wound sections that were previously stained with hematoxylin and eosin were used to assess collagen fiber content and organization at different points during the wound healing process. Overall, wounds exhibited a measurable increase in collagen fiber thickness and a nonlinear change in fiber reorganization within the wound. Our study demonstrates that quantitative polarized light imaging is an inexpensive alternative or supplement to standard histology protocols, requiring no additional stains or dyes, and yields repeatable quantitative assessments of collagen organization.


Assuntos
Colágeno/metabolismo , Processamento de Imagem Assistida por Computador , Microscopia de Polarização/métodos , Pele/lesões , Ferimentos e Lesões/diagnóstico por imagem , Animais , Redução de Custos , Humanos , Microscopia de Polarização/economia , Sensibilidade e Especificidade , Pele/patologia , Lesões dos Tecidos Moles/diagnóstico por imagem , Lesões dos Tecidos Moles/patologia , Cicatrização/fisiologia , Ferimentos e Lesões/patologia
10.
PLoS One ; 14(5): e0214494, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31095594

RESUMO

We introduce a Mueller-matrix imaging polarization-based approach for the quantitative digital screening of the polycrystalline structure of fibrillary-based biological tissues in vitro. The morphometric evaluation of histological sections of myocardium was performed utilizing the high-order statistical moments calculated based on the spatial distribution of linear and circular birefringence and dichroism obtained experimentally. We demonstrate that spatial distributions of phase of light and optical anisotropy of scattering inherent to fibrillar networks of myocardium at different necrotic stages can be effectively used as a quantitative marker of stages of myosin fibril degradation. Processing the images of phase of light scattered in biological tissues with high order statistical analysis provides a functional tool for the quantitative characterization of necrotic conditions of the myocardium.


Assuntos
Anisotropia , Miocárdio/metabolismo , Algoritmos , Birrefringência , Microscopia de Polarização/métodos , Miosinas/metabolismo
11.
Sci Rep ; 9(1): 4823, 2019 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-30886325

RESUMO

Raman microspectroscopy (RM) and polarization sensitive digital holographic imaging (PSDHI) are valuable analytical tools in biological and medical research, allowing the detection of both biochemical and morphological variations of the sample without labels or long sample preparation. Here, using this multi-modal approach we analyze in vitro human sperm capacitation and the acrosome reaction induced by heparin. The multimodal microscopy provides morphofunctional information that can assess the sperms ability to respond to capacitation stimuli (sperm function). More precisely, the birefringence analysis in sperm cells can be used as an indicator of its structural normality. Indeed, digital holography applied for polarization imaging allows for revelation of the polarization state of the sample, showing a total birefringence of the sperm head in non-reacted spermatozoa, and a birefringence localized in the post-acrosomal region in reacted spermatozoa. Additionally, RM allows the detection and spectroscopic characterization of protein/lipid delocalization in the plasma and acrosomal membranes that can be used as valuable Raman biomarkers of sperm function. Interestingly, these spectral variations can be correlated with different time phases of the cell capacitation response. Although further experimentation is required, the proposed multimodal approach could represent a potential label-free diagnostic tool for use in reproductive medicine and the diagnosis of infertility.


Assuntos
Holografia/métodos , Infertilidade/diagnóstico , Análise do Sêmen/métodos , Análise Espectral Raman/métodos , Espermatozoides/fisiologia , Reação Acrossômica/fisiologia , Voluntários Saudáveis , Humanos , Infertilidade/fisiopatologia , Masculino , Microscopia de Fluorescência/métodos , Microscopia de Polarização/métodos , Capacitação Espermática/fisiologia
12.
Ultrastruct Pathol ; 43(1): 13-27, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30898001

RESUMO

Perineal talc use is associated with ovarian carcinoma in many case-control studies. Such talc may migrate to pelvic organs and regional lymph nodes, with both clinical and legal significance. Our goal was to differentiate talc in pelvic lymph nodes due to exposure, versus contamination with talc in the laboratory. We studied 22 lymph nodes from ovarian tumor patients, some of which had documented talc exposure, to quantify talc using digestion of tissue taken from paraffin blocks and scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). Talc particles correlated significantly with surface contamination assessments using polarized light microscopy. After adjusting for surface contamination, talc burdens in nodes correlated strongly with perineal talc use. In a separate group of lymph nodes, birefringent particles within the same plane of focus as the tissues in histological sections were highly correlated with talc particles within the tissue by in situ SEM/EDX (r = 0.80; p < 0.0001). We conclude that since talc can be a surface contaminant from tissue collection/preparation, digestion measurements may be influenced by contamination. Instead, because they preserve anatomic landmarks and permit identification of particles in cells and tissues, polarized light microscopy and in situ SEM/EDX are recommended to assess talc in lymph nodes.


Assuntos
Linfonodos/patologia , Microscopia Eletrônica de Varredura , Neoplasias Ovarianas/patologia , Estudos de Casos e Controles , Feminino , Humanos , Microscopia Eletrônica de Varredura/métodos , Microscopia de Polarização/métodos , Pelve/patologia
13.
J Assist Reprod Genet ; 36(3): 445-452, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30635815

RESUMO

PROPOSE: The presence of metaphase II (MII) spindle together with the polar body (PB) indicates completion of oocyte maturation. This study was designed to explore if spindle imaging can be used to optimize timing of intracytoplasmic sperm injection (ICSI). METHODS: The study involved 916 oocytes from 234 conventionally stimulated ICSI cycles with an unexpectedly poor ovarian response. All PB-displaying oocytes were subjected to polarized light microscopy (PLM) prior to ICSI. When MII spindle was absent in the majority of oocytes, ICSI was postponed and performed after additional spindle imaging. Fertilization, embryo development, and clinical outcome were evaluated with respect to the observed spindle pattern. RESULTS: The visible spindle was absent in 32.64% of PB-displaying oocytes. The late-maturing oocytes extruding PB in vitro were less likely to exhibit a spindle signal than in vivo matured MII oocytes (38.86% vs. 89.84%). When fertilization was postponed, 59.39% of initially spindle-negative oocytes developed detectable MII spindle. Spindled eggs had significantly higher developmental potential, and the presence of the spindle has been identified as an independent measure for predicting the formation of the blastocyst. Embryos derived from spindle-positive oocytes also showed a higher chance to implant and develop to term. Notably, 11 children were conceived by finely timed fertilization of late-maturing oocytes which are normally discarded. CONCLUSIONS: The study confirms the prognostic value of spindle imaging and demonstrates that immature oocytes can be clinically utilized and give rise to live births when the timing of ICSI is adjusted to their developmental stage.


Assuntos
Desenvolvimento Embrionário/genética , Fertilização in vitro , Oócitos/crescimento & desenvolvimento , Injeções de Esperma Intracitoplásmicas , Feminino , Humanos , Metáfase/genética , Microscopia de Polarização , Oócitos/ultraestrutura , Oogênese/genética , Gravidez
14.
J Microsc ; 273(3): 199-209, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30561003

RESUMO

Commercial high-resolution optical microscopes are essential for microscopy imaging; however, they are expensive and bulky, which limits their use in point-of-care devices, resource-limited areas, and real-time imaging of a sample in a large apparatus. In this study, we report a novel compact (10 cm × 5 cm × 5 cm, without the light source) lightweight (∼0.5 kg) submicron-resolution inverted optical microscope at low cost (∼$ 300). Our technique utilises the proximity of the image sensor to a commercial microscope objective lens for compactness of the microscope. The use of an image sensor with a small pixel size helps to reduce the information loss, which provides high-resolution images. Moreover, our technique offers a freedom to tailor the design of microscope according to the required resolution, cost, and portability for specific applications, which makes it a suitable candidate for affordable point-of-care devices. Images of several micron-to-submicron scale patterns and spherical beads are acquired to observe the resolution and quality of the images obtained using our microscope. In addition, we demonstrate the applications of our microscope in various fields such as recording of high-speed water microdroplet formation inside a microfluidic device, high-resolution live cell imaging inside an incubator, and real-time imaging of crack propagation in a sample under stretching by a material testing system (MTS). Therefore, this portable and inexpensive microscope provides the essential functionalities of a bulky expensive high-performance microscope at a lower cost. LAY DESCRIPTION: Microscope is an essential tool in research allowing for observation of microsized objects and life forms. Contemporary commercial high-resolution microscopes have long optical paths involving series of lenses and filters. Although this configuration precisely corrects for optical distortions and produces clear images, it makes modern microscopes very costly and bulky, restricting their usage to low-funded research laboratories and at remote places. We have developed a simple digital microscope with high-resolution but with much smaller size and lighter in weight at low cost by removing the long optical terrain. Our microscope consists of a commercial microscope objective lens for magnification and semiconductor image sensor with small pixels placed right after the lens, both of which are affordable and easily available. The small pixel size helps to translate the magnified analogue sample image to high-resolution digital image. In our paper, we show that our microscope can view micro and submicron-sized patterns and beads. Moreover, our fist-sized microscope can be placed inside an incubator for real-time imaging of cells or rotated sideways for recording submicron-sized crack generation due stretching of novel materials, both of which could not be accomplished with the 2 feet tall laboratory microscopes.


Assuntos
Desenho de Equipamento , Dispositivos Lab-On-A-Chip , Microscopia de Polarização/instrumentação , Animais , Escherichia coli/ultraestrutura , Fibroblastos/ultraestrutura , Holografia , Lentes , Camundongos , Microscopia de Polarização/métodos , Células NIH 3T3 , Oócitos/ultraestrutura , Peixe-Zebra
15.
J Biomed Opt ; 23(12): 1-9, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30369106

RESUMO

Absorption effect is a basic optical phenomenon and an important feature in tissue imaging and characterization. Based on our Monte Carlo simulation on the anisotropic tissue model (sphere-cylinder birefringence model), combined with our experiments of tissue phantoms, we demonstrate the influence of absorption effect on Mueller matrix and particularly on depolarization, linear retardance, and diattenuation parameters. The simulation and experimental results show a good consistency on the suppressed depolarization and scatterering induced retardance, and the enhanced diattenuation caused by the absorption, and also indicate the birefringence induced retardance insensitive to the absorption. Study of the phase function of different incident polarized lights and the distribution of scattering number gives a preliminary explanation about the above results.


Assuntos
Óptica e Fotônica , Anisotropia , Birrefringência , Simulação por Computador , Luz , Modelos Lineares , Microscopia de Polarização , Microesferas , Método de Monte Carlo , Nefelometria e Turbidimetria , Imagens de Fantasmas , Fótons , Poliestirenos/química , Espalhamento de Radiação
16.
J Biophotonics ; 11(11): e201800008, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29931742

RESUMO

Cell contractility regulates multiple cell behaviors which contribute to both normal and pathological processes. However, measuring cell contractility remains a technical challenge in complex biological samples. The current state of the art technologies employed to measure cell contractility have inherent limitations that greatly limit the experimental conditions under which they can be used. Here, we use quantitative polarization microscopy to extract information about cell contractility. We show that the optical retardance signal measured from the cell body is proportional to cell contractility in 2-dimensional and 3-dimensional platforms, and as such can be used as a straightforward, tractable methodology to assess cell contractility in a variety of systems. This label-free optical method provides a novel and flexible way to assess cellular forces of single cells and monolayers in several cell types, fixed or live, in addition to cells present in situ in mouse tumor tissue samples. This easily implementable and experimentally versatile method will significantly contribute to the cell mechanics field.


Assuntos
Células/citologia , Fenômenos Mecânicos , Microscopia de Polarização/métodos , Animais , Fenômenos Biomecânicos , Linhagem Celular Tumoral , Humanos , Camundongos , Fenômenos Ópticos , Ratos
17.
Sci Rep ; 7(1): 14702, 2017 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-29089638

RESUMO

Skin tissue consists of collagen and elastic fibres, which are highly susceptible to damage when exposed to ultraviolet radiation (UVR), leading to skin aging and cancer. However, a lack of non-invasive detection methods makes determining the degree of UVR damage to skin in real time difficult. As one of the fundamental features of light, polarization can be used to develop imaging techniques capable of providing structural information about tissues. In particular, Mueller matrix polarimetry is suitable for detecting changes in collagen and elastic fibres. Here, we demonstrate a novel, quantitative, non-contact and in situ technique based on Mueller matrix polarimetry for monitoring the microstructural changes of skin tissues during UVR-induced photo-damaging. We measured the Mueller matrices of nude mouse skin samples, then analysed the transformed parameters to characterise microstructural changes during the skin photo-damaging and self-repairing processes. Comparisons between samples with and without the application of a sunscreen showed that the Mueller matrix-derived parameters are potential indicators for fibrous microstructure in skin tissues. Histological examination and Monte Carlo simulations confirmed the relationship between the Mueller matrix parameters and changes to fibrous structures. This technique paves the way for non-contact evaluation of skin structure in cosmetics and dermatological health.


Assuntos
Diagnóstico por Imagem/métodos , Modelos Teóricos , Lesões Experimentais por Radiação/diagnóstico , Pele/metabolismo , Animais , Colágeno/metabolismo , Tecido Elástico/metabolismo , Humanos , Camundongos , Camundongos Nus , Microscopia de Polarização , Método de Monte Carlo , Pele/patologia , Protetores Solares/administração & dosagem , Raios Ultravioleta/efeitos adversos , Cicatrização
18.
J Biomed Opt ; 22(6): 65001, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-28586854

RESUMO

Articular surface damage occurs to cartilage during normal aging, osteoarthritis, and in trauma. A noninvasive assessment of cartilage microstructural alterations is useful for studies involving cartilage explants. This study evaluates polarized reflectance microscopy as a tool to assess surface damage to cartilage explants caused by mechanical scraping and enzymatic degradation. Adult bovine articular cartilage explants were scraped, incubated in collagenase, or underwent scrape and collagenase treatments. In an additional experiment, cartilage explants were subject to scrapes at graduated levels of severity. Polarized reflectance parameters were compared with India ink surface staining, features of histological sections, changes in explant wet weight and thickness, and chondrocyte viability. The polarized reflectance signal was sensitive to surface scrape damage and revealed individual scrape features consistent with India ink marks. Following surface treatments, the reflectance contrast parameter was elevated and correlated with image area fraction of India ink. After extensive scraping, polarized reflectance contrast and chondrocyte viability were lower than that from untreated explants. As part of this work, a mathematical model was developed and confirmed the trend in the reflectance signal due to changes in surface scattering and subsurface birefringence. These results demonstrate the effectiveness of polarized reflectance microscopy to sensitively assess surface microstructural alterations in articular cartilage explants.


Assuntos
Cartilagem Articular/diagnóstico por imagem , Microscopia de Polarização , Animais , Birrefringência , Bovinos , Condrócitos/citologia , Osteoartrite/diagnóstico por imagem
19.
J Biophotonics ; 10(3): 433-445, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27060450

RESUMO

The purpose of this study was to evaluate thermal and near-infrared (NIR) reflectance imaging methods for the assessment of the activity of root caries lesions. In addition, changes in the lesion structure were monitored with polarization sensitive optical coherence tomography (PS-OCT). Artificial bovine and natural root caries lesions were imaged with PS-OCT, and their dehydration rate was measured with thermal and NIR cameras. The lesion activity of the natural root caries samples was also assessed by two clinicians by conventional means according to ICDAS II guidelines. The thickness of the highly mineralized transparent surface layer measured using PS-OCT increased and the area enclosed by the time-temperature curve, ΔQ, measured with thermal imaging decreased significantly with longer periods of remineralization in simulated dentin lesions, but the NIR reflectance intensity differences, ΔI, failed to show any significant relationship with the degree of remineralization. The PS-OCT algorithm for the automated assessment of remineralization successfully detected the highly mineralized surface layer on both natural and simulated lesions. Thermal imaging provided the most accurate diagnosis of root caries lesion activity. These results demonstrate that thermal imaging and PS-OCT may be ideally suited for the nondestructive root caries lesion activity during a clinical examination.


Assuntos
Raios Infravermelhos , Cárie Radicular/diagnóstico por imagem , Tomografia de Coerência Óptica , Algoritmos , Animais , Área Sob a Curva , Bovinos , Dentina/diagnóstico por imagem , Dentina/patologia , Humanos , Microrradiografia , Microscopia de Polarização , Modelos Anatômicos , Reconhecimento Automatizado de Padrão , Curva ROC , Cárie Radicular/patologia , Temperatura , Remineralização Dentária
20.
Biol Res ; 49(1): 43, 2016 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-27806731

RESUMO

BACKGROUND: Computer-based technology is becoming increasingly essential in biological research where drug discovery programs start with the identification of suitable drug targets. 2-Methoxyestradiol (2ME2) is a 17ß-estradiol metabolite that induces apoptosis in various cancer cell lines including cervical cancer, breast cancer and multiple myeloma. Owing to 2ME2's poor in vivo bioavailability, our laboratory in silico-designed and subsequently synthesized a novel 2ME2 analogue, 2-ethyl-3-O-sulphamoyl-estra-1,3,5(10),15-tetraen-17-ol (ESE-15-ol), using receptor- and ligand molecular modeling. In this study, the biological effects of ESE-15-ol (180 nM) and its parent molecule, 2ME2 (1 µM), were assessed on morphology and apoptosis induction in cervical cancer cells. RESULTS: Transmission electron microscopy, scanning electron microscopy and polarization-optical transmitted light differential interference contrast (PlasDIC) images demonstrated morphological hallmarks of apoptosis including apoptotic bodies, shrunken cells, vacuoles, reduced cell density and cell debris. Flow cytometry analysis showed apoptosis induction by means of annexin V-FITC staining. Cell cycle analysis showed that ESE-15-ol exposure resulted in a statistically significant increase in the G2M phase (72%) compared to 2ME2 (19%). Apoptosis induction was more pronounced when cells were exposed to ESE-15-ol compared to 2ME2. Spectrophotometric analysis of caspase 8 activity demonstrated that 2ME2 and ESE-15-ol both induced caspase 8 activation by 2- and 1.7-fold respectively indicating the induction of the apoptosis. However, ESE-15-ol exerted all of the above-mentioned effects at a much lower pharmacological concentration (180 nM) compared to 2ME2 (1 µM physiological concentration). CONCLUSION: Computer-based technology is essential in drug discovery and together with in vitro studies for the evaluation of these in silico-designed compounds, drug development can be improved to be cost effective and time consuming. This study evaluated the anticancer potential of ESE-15-ol, an in silico-designed compound in vitro. Research demonstrated that ESE-15-ol exerts antiproliferative activity accompanied with apoptosis induction at a nanomolar concentration compared to the micromolar range required by 2ME2. This study is the first study to demonstrate the influence of ESE-15-ol on morphology, cell cycle progression and apoptosis induction in HeLa cells. In silico-design by means of receptor- and ligand molecular modeling is thus effective in improving compound bioavailability while preserving apoptotic activity in vitro.


Assuntos
Antineoplásicos/farmacologia , Inibidores da Anidrase Carbônica/farmacologia , Desenho Assistido por Computador , Estradiol/análogos & derivados , Sulfonamidas/farmacologia , Neoplasias do Colo do Útero/tratamento farmacológico , 2-Metoxiestradiol , Apoptose/efeitos dos fármacos , Caspase 8/metabolismo , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/fisiologia , Células Cultivadas , Meios de Cultura , Estradiol/farmacologia , Feminino , Citometria de Fluxo/métodos , Células HeLa , Humanos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Microscopia de Polarização , Reprodutibilidade dos Testes , Fatores de Tempo , Neoplasias do Colo do Útero/patologia
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