Skin autofluorescence as a measure of advanced glycation endproduct deposition: a novel risk marker in chronic kidney disease.

PubMed

Smit, Andries J; Gerrits, Esther G

2010-11-01

Skin autofluorescence (SAF) is a new method to noninvasively assess accumulation of advanced glycation endproducts (AGEs) in a tissue with low turnover. Recent progress in the clinical application of SAF as a risk marker for diabetic nephropathy as well as cardiovascular disease in nondiabetic end-stage kidney disease, less advanced chronic kidney disease, and renal transplant recipients is reviewed. Experimental studies highlight the fundamental role of the interaction of AGEs with the receptor for AGEs (RAGEs), also called the AGE-RAGE axis, in the pathogenesis of vascular and chronic kidney disease. SAF predicts (cardiovascular) mortality in renal failure and also chronic renal transplant dysfunction. Long-term follow-up results from the Diabetes Control and Complications Trial and UK Prospective Diabetes Study suggest that AGE accumulation is a key carrier of metabolic memory and oxidative stress. Short-term intervention studies in diabetic nephropathy with thiamine, benfotiamine and angiotensin-receptor blockers aimed at reducing AGE formation have reported mixed results. SAF is a noninvasive marker of AGE accumulation in a tissue with low turnover, and thereby of metabolic memory and oxidative stress. SAF independently predicts cardiovascular and renal risk in diabetes, as well as in chronic kidney disease. Further long-term studies are required to assess the potential benefits of interventions to reduce AGE accumulation.

Autofluorescence dynamics during reperfusion following long-term renal ischemia in a rat model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raman, R N; Pivetti, C D; Matthews, D L

2008-02-08

Optical properties of near-surface kidney tissue were monitored in order to assess response during reperfusion to long (20 minutes) versus prolonged (150 minutes) ischemia in an in vivo rat model. Specifically, autofluorescence images of the exposed surfaces of both the normal and the ischemic kidneys were acquired during both injury and reperfusion alternately under 355 nm and 266 nm excitations. The temporal profile of the emission of the injured kidney during the reperfusion phase under 355 nm excitation was normalized to that under 266 nm as a means to account for changes in tissue optical properties independent of ischemia asmore » well as changes in the illumination/collection geometrical parameters in future clinical implementation of this technique using a hand-held probe. The scattered excitation light signal was also evaluated as a reference signal and found to be inadequate. Characteristic time constants were extracted using fit to a relaxation model and found to have larger mean values following 150 minutes of injury. The mean values were then compared with the outcome of a chronic survival study where the control kidney had been removed. Rat kidneys exhibiting longer time constants were much more likely to fail. This may lead to a method to assess kidney viability and predict its ability to recover in the initial period following transplantation or resuscitation.« less

Autofluorescence of human cells in vitro as a biomarker of their metabolic activity

NASA Astrophysics Data System (ADS)

Dobrzyńska, Monika; Stepińska, Małgorzata; Lewandowski, Rafał; Gietka, Andrzej; Łapiński, Mariusz P.; Trafny, ElŻbieta A.

2016-12-01

Autofluorescence (AF) is the natural emission of light by intrinsic fluorophores. Oxidized mitochondrial flavins, lipofuscin and reduced nicotinamideadenine dinucleotide phosphate (NAD(P)H) are the main sources of the autofluorescence in cells upon excitation with visible light. The aim of the study was to investigate changes in the metabolism of four cell lines by monitoring their autofluorescence with a microplate reader. Autofluorescence intensities of cells were collected at two wavelengths for the excitation and fluorescence emission: for endogenous NAD(P)H at 366/450 nm, for the oxidized flavoproteins and lipofuscin at 460/540 nm. Human mesenchymal stem cells (hMSC), epithelial cells from mammary gland (MCF 10A), breast ductal carcinoma (T-47D) prostate carcinoma (DU-145) were observed daily for 16 days. The level of NAD(P)H autofluorescence did not differ among the cell lines investigated. The significant increase in oxidized flavoproteins fluorescence intensity was recorded for hMSC and ranged from 140 to 175% of control. During 28 days differentiation process, the NAD(P)H, FAD and lipofuscin fluorescence intensities were recorded every day, and the redox ratio was then calculated. The redox ratio gradually decreased during the last eight days of osteogenesis and adipogenesis. Therefore, in our opinion the NAD(P)H, FAD, and lipofuscin fluorescence emission at the wavelengths selected are the optimal parameters to be collected during the differentiation process in order to monitor the metabolism of hMSC undergoing structural and morphological changes.

Fundus autofluorescence findings in a mouse model of retinal detachment.

PubMed

Secondi, Roberta; Kong, Jian; Blonska, Anna M; Staurenghi, Giovanni; Sparrow, Janet R

2012-08-07

Fundus autofluorescence (fundus AF) changes were monitored in a mouse model of retinal detachment (RD). RD was induced by transscleral injection of hyaluronic acid (Healon) or sterile balanced salt solution (BSS) into the subretinal space of 4-5-day-old albino Abca4 null mutant and Abca4 wild-type mice. Images acquired by confocal scanning laser ophthalmoscopy (Spectralis HRA) were correlated with spectral domain optical coherence tomography (SD-OCT), infrared reflectance (IR), fluorescence spectroscopy, and histologic analysis. Results. In the area of detached retina, multiple hyperreflective spots in IR images corresponded to punctate areas of intense autofluorescence visible in fundus AF mode. The puncta exhibited changes in fluorescence intensity with time. SD-OCT disclosed undulations of the neural retina and hyperreflectivity of the photoreceptor layer that likely corresponded to histologically visible photoreceptor cell rosettes. Fluorescence emission spectra generated using flat-mounted retina, and 488 and 561 nm excitation, were similar to that of RPE lipofuscin. With increased excitation wavelength, the emission maximum shifted towards longer wavelengths, a characteristic typical of fundus autofluorescence. In detached retinas, hyper-autofluorescent spots appeared to originate from photoreceptor outer segments that were arranged within retinal folds and rosettes. Consistent with this interpretation is the finding that the autofluorescence was spectroscopically similar to the bisretinoids that constitute RPE lipofuscin. Under the conditions of a RD, abnormal autofluorescence may arise from excessive production of bisretinoid by impaired photoreceptor cells.

Development of an autofluorescent probe designed to help brain tumor removal: study on an animal model

NASA Astrophysics Data System (ADS)

Siebert, R.; Leh, B.; Charon, Y.; Collado-Hilly, M.; Duval, M.-A.; Menard, L.; Monnet, F. P.; Varlet, P.

2010-02-01

The complete resection of the brain tumour is crucial to the patient life quality and prognosis. An autofluorescence probe aiming at helping the surgeon to improve the completeness of the removal is being developed. Autofluorescence spectroscopy is a promising approach to define whether the tissue is cancerous or not. First ex vivo measurements have been realised on an animal model. After tumorous cell injection in rat brain, autofluorescence intensity is revealed from the extracted brain. These autofluorescence data are compared to results from a histological analysis of same brains. First indicators are identified that may have the ability to differentiate tumorous and healthy tissues.

Skin autofluorescence photo-bleaching and photo-memory

NASA Astrophysics Data System (ADS)

Lesins, Janis; Lihachev, Alexey; Rudys, Romualdas; Bagdonas, Saulius; Spigulis, Janis

2011-07-01

Photo-bleaching of in-vivo skin autofluorescence intensity under continuous low power laser irradiation has been studied. Temporal behavior of single-spot fluorescence and spectral fluorescent images have been studied at continuous 405 nm, 473 nm and 532 nm laser excitation and/or pre-irradiation, with power densities well below the laser-skin safety limits. Skin autofluorescence photo-memory effects (laser signatures) have been observed and analyzed, as well.

Fundus Autofluorescence Findings in a Mouse Model of Retinal Detachment

PubMed Central

Secondi, Roberta; Kong, Jian; Blonska, Anna M.; Staurenghi, Giovanni; Sparrow, Janet R.

2012-01-01

Purpose. Fundus autofluorescence (fundus AF) changes were monitored in a mouse model of retinal detachment (RD). Methods. RD was induced by transscleral injection of hyaluronic acid (Healon) or sterile balanced salt solution (BSS) into the subretinal space of 4–5-day-old albino Abca4 null mutant and Abca4 wild-type mice. Images acquired by confocal scanning laser ophthalmoscopy (Spectralis HRA) were correlated with spectral domain optical coherence tomography (SD-OCT), infrared reflectance (IR), fluorescence spectroscopy, and histologic analysis. Results. In the area of detached retina, multiple hyperreflective spots in IR images corresponded to punctate areas of intense autofluorescence visible in fundus AF mode. The puncta exhibited changes in fluorescence intensity with time. SD-OCT disclosed undulations of the neural retina and hyperreflectivity of the photoreceptor layer that likely corresponded to histologically visible photoreceptor cell rosettes. Fluorescence emission spectra generated using flat-mounted retina, and 488 and 561 nm excitation, were similar to that of RPE lipofuscin. With increased excitation wavelength, the emission maximum shifted towards longer wavelengths, a characteristic typical of fundus autofluorescence. Conclusions. In detached retinas, hyper-autofluorescent spots appeared to originate from photoreceptor outer segments that were arranged within retinal folds and rosettes. Consistent with this interpretation is the finding that the autofluorescence was spectroscopically similar to the bisretinoids that constitute RPE lipofuscin. Under the conditions of a RD, abnormal autofluorescence may arise from excessive production of bisretinoid by impaired photoreceptor cells. PMID:22786896

Skin autofluorescence as a novel marker of vascular damage in children and adolescents with chronic kidney disease.

PubMed

Makulska, Irena; Szczepańska, Maria; Drożdż, Dorota; Polak-Jonkisz, Dorota; Zwolińska, Danuta

2015-05-01

Skin autofluorescence (sAF) was examined as a marker of the accumulation of advanced glycation end products (AGEs) in tissues of children with chronic kidney disease (CKD) in relation to renal function, dialysis modality and markers of endothelial inflammation and dysfunction. A total of 76 children with CKD were enrolled in the study, of whom 20 children were on hemodialysis (HD), 20 were on peritoneal dialysis (PD) and 36 were treated conservatively. A control group of 26 healthy subjects was also included in the study. In all children, sAF intensity, carotid intima-media (cIMT) thickness and plasma concentrations of sE-selectin, matrix metalloproteinase 9 (MMP-9), tissue inhibitor of metalloproteinase 1 (TIMP-1), asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and plasminogen activator inhibitor type 1 (PAI-1) were measured. Compared to the controls, children with CKD had significantly elevated sAF levels. sAF in the children with CKD was positively correlated with sE-selectin, MMP-9, TIMP-1, ADMA, SDMA and PAI-1 levels. In the predialysis group (conservative treatment) sAF levels were positively correlated with sE-selectin and ADMA levels and negatively correlated with glomerular filtration rate. Multiple regression analysis showed a significant association of sAF with sE-selectin and MMP-9 in CKD children. The results reveal that AGEs were accumulated in the children with CKD. This accumulation was related to early vascular changes and a number of biochemical vascular risk markers. sAF measurement, as a noninvasive method, may be useful for identification of clinical risk factors of vascular disease in CKD children.

Combination of confocal principle and aperture stop separation improves suppression of crystalline lens fluorescence in an eye model.

PubMed

Klemm, Matthias; Blum, Johannes; Link, Dietmar; Hammer, Martin; Haueisen, Jens; Schweitzer, Dietrich

2016-09-01

Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a new technique to detect changes in the human retina. The autofluorescence decay over time, generated by endogenous fluorophores, is measured in vivo. The strong autofluorescence of the crystalline lens, however, superimposes the intensity decay of the retina fluorescence, as the confocal principle is not able to suppress it sufficiently. Thus, the crystalline lens autofluorescence causes artifacts in the retinal fluorescence lifetimes determined from the intensity decays. Here, we present a new technique to suppress the autofluorescence of the crystalline lens by introducing an annular stop into the detection light path, which we call Schweitzer's principle. The efficacy of annular stops with an outer diameter of 7 mm and inner diameters of 1 to 5 mm are analyzed in an experimental setup using a model eye based on fluorescent dyes. Compared to the confocal principle, Schweitzer's principle with an inner diameter of 3 mm is able to reduce the simulated crystalline lens fluorescence to 4%, while 42% of the simulated retina fluorescence is preserved. Thus, we recommend the implementation of Schweitzer's principle in scanning laser ophthalmoscopes used for fundus autofluorescence measurements, especially the FLIO device, for improved image quality.

Iris autofluorescence in Fuchs' heterochromic uveitis.

PubMed

Liu, Qian; Jia, Yading; Zhang, Suhua; Xie, Juan; Chang, Xin; Hou, Jia; Li, Gaiyun; Koch, Douglas D; Wang, Li

2016-10-01

To explore the characteristic autofluorescence patterns of iris depigmentation in eyes diagnosed with Fuchs' heterochromic uveitis (FHU). Near-infrared autofluorescence images and colour images of iris were taken in 21 eyes of 21 patients with FHU, 30 eyes of 15 normal subjects, 30 eyes of 15 normal age-related iris atrophy and 33 eyes of 20 patients with uveitis other than FHU. The confocal scanning laser ophthalmoscope (Heidelberg Retina Angiograph 2, HRA2) was used for melanin-related autofluorescence imaging. The indocyanine green angiography mode of HRA2 was applied for near-infrared laser imaging, and the wavelength of the excitation laser was 795 nm. Iris colour images were also taken with the slit lamp. In normal iris, moderately intense autofluorescence was noted for the pigment ruff at the pupillary border, the crests in the pupillary zone and the collarette; and there was mild autofluorescence in the ciliary zone. In eyes with age-related iris atrophy and uveitis, much less autofluorescence was seen than the healthy normal irides. In eyes with FHU, there was moderate but discontinuous autofluorescence in the pigment ruff, a petaloid pattern of autofluorescence in the pupillary zone, moderate autofluorescence in the collarette and reticular pattern of autofluorescence in the ciliary zone. Characteristic autofluorescence patterns appeared in eyes diagnosed with FHU. Near-infrared autofluorescence is a promising objective technique to document the iris changes in FHU. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Autofluorescence imaging of basal cell carcinoma by smartphone RGB camera

NASA Astrophysics Data System (ADS)

Lihachev, Alexey; Derjabo, Alexander; Ferulova, Inesa; Lange, Marta; Lihacova, Ilze; Spigulis, Janis

2015-12-01

The feasibility of smartphones for in vivo skin autofluorescence imaging has been investigated. Filtered autofluorescence images from the same tissue area were periodically captured by a smartphone RGB camera with subsequent detection of fluorescence intensity decreasing at each image pixel for further imaging the planar distribution of those values. The proposed methodology was tested clinically with 13 basal cell carcinoma and 1 atypical nevus. Several clinical cases and potential future applications of the smartphone-based technique are discussed.

Autofluorescence imaging of basal cell carcinoma by smartphone RGB camera.

PubMed

Lihachev, Alexey; Derjabo, Alexander; Ferulova, Inesa; Lange, Marta; Lihacova, Ilze; Spigulis, Janis

2015-01-01

The feasibility of smartphones for in vivo skin autofluorescence imaging has been investigated. Filtered autofluorescence images from the same tissue area were periodically captured by a smartphone RGB camera with subsequent detection of fluorescence intensity decreasing at each image pixel for further imaging the planar distribution of those values. The proposed methodology was tested clinically with 13 basal cell carcinoma and 1 atypical nevus. Several clinical cases and potential future applications of the smartphone-based technique are discussed.

Assessment of different excitation wavelengths for photodetecting neoplastic urothelial lesions by laser-induced autofluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Anidjar, Maurice; Cussenot, Oliver; Avrillier, Sigrid; Ettori, Dominique; Teillac, Pierre; Le Duc, Alain

1996-04-01

We have designed a program using laser induced autofluorescence spectroscopy as a possible way to characterize urothelial tumors of the bladder. The autofluorescence spectra were compared between normal, suspicious and tumor areas of human bladder. Three different pulsed laser wavelengths were used for excitation: 308 nm (excimer), 337 nm (nitrogen) and 480 nm (dye laser). Excitation light was delivered by a specially devised multifiber catheter introduced through the working channel of a regular cystoscope under saline irrigation. The fluorescence light was focused into an optical multichannel analyzer detection system. The data was evaluated in 25 patients immediately before resection of a bladder tumor. Spectroscopic results were compared with histopathology. Upon 337 nm and 480 nm excitations, the overall intensity of the fluorescence spectra from bladder tumors was clearly reduced in comparison with normal urothelium, regardless of the stage and the grade of the tumor. upon 308 nm excitation, the shape of tumor fluorescence spectra, including carcinoma in situ, differed drastically from that of normal tissue. In this case, no absolute intensity measurements are needed and clear diagnosis can be achieved from fluorescence intensity ratio (360/440 nm). This spectroscopic study could be particularly useful for the design of a simplified autofluorescence imaging device for real-time routine detection of occult urothelial neoplastic lesions.

Combination of confocal principle and aperture stop separation improves suppression of crystalline lens fluorescence in an eye model

PubMed Central

Klemm, Matthias; Blum, Johannes; Link, Dietmar; Hammer, Martin; Haueisen, Jens; Schweitzer, Dietrich

2016-01-01

Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a new technique to detect changes in the human retina. The autofluorescence decay over time, generated by endogenous fluorophores, is measured in vivo. The strong autofluorescence of the crystalline lens, however, superimposes the intensity decay of the retina fluorescence, as the confocal principle is not able to suppress it sufficiently. Thus, the crystalline lens autofluorescence causes artifacts in the retinal fluorescence lifetimes determined from the intensity decays. Here, we present a new technique to suppress the autofluorescence of the crystalline lens by introducing an annular stop into the detection light path, which we call Schweitzer’s principle. The efficacy of annular stops with an outer diameter of 7 mm and inner diameters of 1 to 5 mm are analyzed in an experimental setup using a model eye based on fluorescent dyes. Compared to the confocal principle, Schweitzer’s principle with an inner diameter of 3 mm is able to reduce the simulated crystalline lens fluorescence to 4%, while 42% of the simulated retina fluorescence is preserved. Thus, we recommend the implementation of Schweitzer’s principle in scanning laser ophthalmoscopes used for fundus autofluorescence measurements, especially the FLIO device, for improved image quality. PMID:27699092

Optimized endoscopic autofluorescence spectroscopy for the identification of premalignant lesions in Barrett's oesophagus.

PubMed

Holz, Jasmin A; Boerwinkel, David F; Meijer, Sybren L; Visser, Mike; van Leeuwen, Ton G; Aalders, Maurice C G; Bergman, Jacques J G H M

2013-12-01

Fluorescence spectroscopy has the potential to detect early cellular changes in Barrett's oesophagus before these become visible. As the technique is based on varying concentrations of intrinsic fluorophores, each with its own optimal excitation wavelength, it is important to assess the optimal excitation wavelength(s) for identification of premalignant lesions in patients with Barrett's oesophagus. The endoscopic spectroscopy system used contained five (ultra)violet light sources (λexc=369-416 nm) to generate autofluorescence during routine endoscopic surveillance. Autofluorescence spectroscopy was followed by a biopsy for histological assessment and spectra correlation. Three intensity ratios (r1, r2, r3) were calculated by dividing the area, A, under the spectral curve of selected emission wavelength ranges for each spectrum generated by each excitation wavelength λexc as follows (Equation is included in full-text article.). Double intensity ratios were calculated using two excitation wavelengths. Fifty-eight tissue areas from 22 patients were used for autofluorescence spectra analysis. Excitation with 395, 405 or 410 nm showed a significant (P≤0.0006) differentiation between intestinal metaplasia and grouped high-grade dysplasia/early carcinoma for intensity ratios r2 and r3. A sensitivity of 80.0% and specificity of 89.5% with an area under the ROC curve of 0.85 was achieved using 395 nm excitation and intensity ratio r3. Double excitation showed no additional value over single excitation. The combination of 395 nm excitation and intensity ratio r3 showed optimal conditions to discriminate nondysplastic from early neoplasia in Barrett's oesophagus.

Tryptophan autofluorescence imaging of neoplasms of the human colon

NASA Astrophysics Data System (ADS)

Banerjee, Bhaskar; Renkoski, Timothy; Graves, Logan R.; Rial, Nathaniel S.; Tsikitis, Vassiliki Liana; Nfonsom, Valentine; Pugh, Judith; Tiwari, Piyush; Gavini, Hemanth; Utzinger, Urs

2012-01-01

Detection of flat neoplasia is a major challenge in colorectal cancer screening, as missed lesions can lead to the development of an unexpected `incident' cancer prior to the subsequent endoscopy. The use of a tryptophan-related autofluorescence has been reported to be increased in murine intestinal dysplasia. The emission spectra of cells isolated from human adenocarcinoma and normal mucosa of the colon were studied and showed markedly greater emission intensity from cancerous cells compared to cells obtained from the surrounding normal mucosa. A proto-type multispectral imaging system optimized for ultraviolet macroscopic imaging of tissue was used to obtain autofluorescence images of surgical specimens of colonic neoplasms and normal mucosa after resection. Fluorescence images did not display the expected greater emission from the tumor as compared to the normal mucosa, most probably due to increased optical absorption and scattering in the tumors. Increased fluorescence intensity in neoplasms was observed however, once fluorescence images were corrected using reflectance images. Tryptophan fluorescence alone may be useful in differentiating normal and cancerous cells, while in tissues its autofluorescence image divided by green reflectance may be useful in displaying neoplasms.

Light-induced fluorescence for pulpal diagnosis

NASA Astrophysics Data System (ADS)

Ebihara, Arata; Liaw, Lih-Huei L.; Krasieva, Tatiana B.; Wilder-Smith, Petra B. B.

2001-04-01

A direct non-histological means of pulpal diagnosis remains elusive to clinical practice. Clinical vitality testing remains limited to electric, thermal criteria, or laser Doppler flowmetry. The goal of these investigations was to determine the feasibility of using light-induced fluorescence as a non-invasive modality for pulpal evaluation. Such a capability would, for example, permit expanded use of pulpotomy/pulpectomy techniques. Clinically healthy and diseased human extirpated pulpal tissues were used in this study. After excision, they were rapidly frozen and standard cryosections prepared. Measurement of tissue excitation/emission characteristics was performed using spectrographic analysis. A low-light level fluorescence microscopy system was then used to image autofluorescence localization and intensity at optimal excitation/detection parameters. Excitation/detection parameters used in this study included 405/605, 405/635, 405/670, 440/550, and 440/635. Autofluorescence intensities in healthy tissues were significantly stronger than those in diseased tissues at optimal parameters. It is postulated that autofluorescence characteristics are related to pathology- related structural changes in the pulp. This work provides the basis for further investigation into the relation between autofluorescence, histology and clinical symptoms.

Analysis of cellular autofluorescence in touch samples by flow cytometry: implications for front end separation of trace mixture evidence.

PubMed

Katherine Philpott, M; Stanciu, Cristina E; Kwon, Ye Jin; Bustamante, Eduardo E; Greenspoon, Susan A; Ehrhardt, Christopher J

2017-07-01

The goal of this study was to survey optical and biochemical variation in cell populations deposited onto a surface through touch or contact and identify specific features that may be used to distinguish and then sort cell populations from separate contributors in a trace biological mixture. Although we were not able to detect meaningful biochemical variation in touch samples deposited by different contributors through preliminary antibody surveys, we did observe distinct differences in red autofluorescence emissions (650-670 nm), with as much as a tenfold difference in mean fluorescence intensities observed between certain pairs of donors. Results indicate that the level of red autofluorescence in touch samples can be influenced by a donor's contact with specific material prior to handling the substrate from which cells were collected. In particular, we observed increased red autofluorescence in cells deposited subsequent to handling laboratory gloves, plant material, and certain types of marker ink, which could be easily visualized microscopically or using flow cytometry, and persisted after hand washing. To test whether these observed optical differences could potentially be used as the basis for a cell separation workflow, a controlled two-person touch mixture was separated into two fractions via fluorescence-activated cell sorting (FACS) using gating criteria based on intensity of 650-670 nm emissions and then subjected to DNA analysis. Genetic analysis of the sorted fractions provided partial DNA profiles that were consistent with separation of individual contributors from the mixture suggesting that variation in autofluorescence signatures, even if driven by extrinsic factors, may nonetheless be a useful means of isolating contributors to some touch mixtures. Graphical Abstract Conceptual workflow diagram. Trace biological mixtures containing cells from multiple individuals are analyzed by flow cytometry. Cells are then physically separated into two populations based on intensity of red autofluorescence using Fluorescence Activated Cell Sorting. Each isolated cell fraction is subjected to DNA analysis resulting in a DNA profile for each contributor.

Multiphoton imaging for assessing renal disposition in acute kidney injury

NASA Astrophysics Data System (ADS)

Liu, Xin; Liang, Xiaowen; Wang, Haolu; Roberts, Darren M.; Roberts, Michael S.

2016-11-01

Estimation of renal function and drug renal disposition in acute kidney injury (AKI), is important for appropriate dosing of drugs and adjustment of therapeutic strategies, but is challenging due to fluctuations in kidney function. Multiphoton microscopy has been shown to be a useful tool in studying drug disposition in liver and can reflect dynamic changes of liver function. We extend this imaging technique to investigate glomerular filtration rate (GFR) and tubular transporter functional change in various animal models of AKI, which mimic a broad range of causes of AKI such as hypoxia (renal ischemia- reperfusion), therapeutic drugs (e.g. cisplatin), rhabdomyolysis (e.g. glycerol-induced) and sepsis (e.g. LPSinduced). The MPM images revealed acute injury of tubular cells as indicated by reduced autofluorescence and cellular vacuolation in AKI groups compared to control group. In control animal, systemically injected FITC-labelled inulin was rapidly cleared from glomerulus, while the clearance of FITC-inulin was significantly delayed in most of animals in AKI group, which may reflect the reduced GFR in AKI. Following intravenous injection, rhodamine 123, a fluorescent substrate of p-glycoprotein (one of tubular transporter), was excreted into urine in proximal tubule via p-glycoprotein; in response to AKI, rhodamine 123 was retained in tubular cells as revealed by slower decay of fluorescence intensity, indicating P-gp transporter dysfunction in AKI. Thus, real-time changes in GFR and transporter function can be imaged in rodent kidney with AKI using multiphoton excitation of exogenously injected fluorescent markers.

A Study of Aberrant Glycosylation in Simulated Microgravity Using Laser Induced AutoFluorescence and Flow Cytometry

NASA Technical Reports Server (NTRS)

Lawless, B. DeSales

1999-01-01

A number of pathologies and cellular dysfunctions including neoplasms have been correlated with autofluorescence. The complications of aging and diabetes have been associated with the accumulation of non-enzymatic glycosylations of tissue macromolecules. These products are known as the Advanced Glycosylated End Products (AGEs). A physical property associated with AGEs is the emission of 570 mn or 630 nm light energy (autofluorescence) following the absorption of 448 mm energy associated with the argon laser. This investigation sought to assess the induction of argon-laser induced autofluorescence in a variety of in vitro culture systems. Different fluorescence intensities distinguished tumor lines from normal cell populations. Laser-stimulated autofluorescence discriminated primary cultures of lymphocytes grown in the presence of excess glucose as opposed to normal glucose concentrations. The effects of deglycosylating agents upon laser-induced autofluorescence were also assessed. The studies included studies of cell cycle analysis using Propidium Iodide stained DNA of cells grown in simulated microgravity using NASA Bioreactor Vessels in media of normal and elevated glucose concentrations.

Novel quantitative analysis of autofluorescence images for oral cancer screening.

PubMed

Huang, Tze-Ta; Huang, Jehn-Shyun; Wang, Yen-Yun; Chen, Ken-Chung; Wong, Tung-Yiu; Chen, Yi-Chun; Wu, Che-Wei; Chan, Leong-Perng; Lin, Yi-Chu; Kao, Yu-Hsun; Nioka, Shoko; Yuan, Shyng-Shiou F; Chung, Pau-Choo

2017-05-01

VELscope® was developed to inspect oral mucosa autofluorescence. However, its accuracy is heavily dependent on the examining physician's experience. This study was aimed toward the development of a novel quantitative analysis of autofluorescence images for oral cancer screening. Patients with either oral cancer or precancerous lesions and a control group with normal oral mucosa were enrolled in this study. White light images and VELscope® autofluorescence images of the lesions were taken with a digital camera. The lesion in the image was chosen as the region of interest (ROI). The average intensity and heterogeneity of the ROI were calculated. A quadratic discriminant analysis (QDA) was utilized to compute boundaries based on sensitivity and specificity. 47 oral cancer lesions, 54 precancerous lesions, and 39 normal oral mucosae controls were analyzed. A boundary of specificity of 0.923 and a sensitivity of 0.979 between the oral cancer lesions and normal oral mucosae were validated. The oral cancer and precancerous lesions could also be differentiated from normal oral mucosae with a specificity of 0.923 and a sensitivity of 0.970. The novel quantitative analysis of the intensity and heterogeneity of VELscope® autofluorescence images used in this study in combination with a QDA classifier can be used to differentiate oral cancer and precancerous lesions from normal oral mucosae. Copyright © 2017 Elsevier Ltd. All rights reserved.

Differentiation of seborrheic keratosis from basal cell carcinoma, nevi and melanoma by RGB autofluorescence imaging

PubMed Central

Lihachev, Alexey; Lihacova, Ilze; Plorina, Emilija V.; Lange, Marta; Derjabo, Alexander; Spigulis, Janis

2018-01-01

A clinical trial on the autofluorescence imaging of skin lesions comprising 16 dermatologically confirmed pigmented nevi, 15 seborrheic keratosis, 2 dysplastic nevi, histologically confirmed 17 basal cell carcinomas and 1 melanoma was performed. The autofluorescence spatial properties of the skin lesions were acquired by smartphone RGB camera under 405 nm LED excitation. The diagnostic criterion is based on the calculation of the mean autofluorescence intensity of the examined lesion in the spectral range of 515 nm–700 nm. The proposed methodology is able to differentiate seborrheic keratosis from basal cell carcinoma, pigmented nevi and melanoma. The sensitivity and specificity of the proposed method was estimated as being close to 100%. The proposed methodology and potential clinical applications are discussed in this article. PMID:29675324

Differentiation of seborrheic keratosis from basal cell carcinoma, nevi and melanoma by RGB autofluorescence imaging.

PubMed

Lihachev, Alexey; Lihacova, Ilze; Plorina, Emilija V; Lange, Marta; Derjabo, Alexander; Spigulis, Janis

2018-04-01

A clinical trial on the autofluorescence imaging of skin lesions comprising 16 dermatologically confirmed pigmented nevi, 15 seborrheic keratosis, 2 dysplastic nevi, histologically confirmed 17 basal cell carcinomas and 1 melanoma was performed. The autofluorescence spatial properties of the skin lesions were acquired by smartphone RGB camera under 405 nm LED excitation. The diagnostic criterion is based on the calculation of the mean autofluorescence intensity of the examined lesion in the spectral range of 515 nm-700 nm. The proposed methodology is able to differentiate seborrheic keratosis from basal cell carcinoma, pigmented nevi and melanoma. The sensitivity and specificity of the proposed method was estimated as being close to 100%. The proposed methodology and potential clinical applications are discussed in this article.

Suppression of Red Blood Cell Autofluorescence for Immunocytochemistry on Fixed Embryonic Mouse Tissue.

PubMed

Whittington, Niteace C; Wray, Susan

2017-10-23

Autofluorescence is a problem that interferes with immunofluorescent staining and complicates data analysis. Throughout the mouse embryo, red blood cells naturally fluoresce across multiple wavelengths, spanning the emission and excitation spectra of many commonly used fluorescent reporters, including antibodies, dyes, stains, probes, and transgenic proteins, making it difficult to distinguish assay fluorescence from endogenous fluorescence. Several tissue treatment methods have been developed to bypass this issue with varying degrees of success. Sudan Black B dye has been commonly used to quench autofluorescence, but can also introduce background fluorescence. Here we present a protocol for an alternative called TrueBlack Lipofuscin Autofluorescence Quencher. The protocol described in this unit demonstrates how TrueBlack efficiently quenches red blood cell autofluorescence across red and green wavelengths in fixed embryonic tissue without interfering with immunofluorescent signal intensity or introducing background staining. We also identify optimal incubation, concentration, and multiple usage conditions for routine immunofluorescence microscopy. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

Autofluorescence of seborrheic keratosis (warts) and of tissue surrounding malignant tumors

NASA Astrophysics Data System (ADS)

Lohmann, Wolfgang; Schill, Wolf-Bernhard; Bohle, Rainer M.; Dreyer, Thomas

1997-12-01

Autofluorescence measurements on human tissue have revealed a decrease in intensity in malignant tumors and an increase in the healthy region adjacent to the tumor. This latter event might serve as a protective wall against the invasive tumor cells. The composition of this wall is still unknown. Antioxidants such as NADH might be involved. In the case of seborrheic keratosis (wart), the intensity is increased in the pigmented spots. Care must be taken, therefore, when warts are attached to malignant tumors. The resulting value is, then, not indicative for the condition of the system.

Application of laser-induced autofluorescence spectra detection system in human colorectal cancer in-vivo screening

NASA Astrophysics Data System (ADS)

Chia, Teck Chee; Fu, Sheng; Chia, Yee Hong; Kwek, Leong Chuan; Tang, Choong Leong

2005-09-01

This study aimed at applying Laser induced-autofluorescence (LIAF) diagnostics method as an in-vivo screening of colorectal polyplcancer. The spectrum algorithm based on the ratio of autofluorescence intensity was used to identify the diseased tissues from the normal tissues as it was generally performed better than an algorithm based only simply on the intensity of the spectrum. Histopathological biopsy results were compared with the detected AF spectra characteristics for different kinds of polyps. 73 patients had been examined via the LIAF spectroscopy detection system during their colonoscopy screening in Endoscopy Center, Singapore General Hospital. The autofluorescence from the surface of the colorectal tissues under 405 nm laser light excitation was detected using our detecting system. In the experimental investigation two groups of patients were involved. One group was "abnormal" group. There were 25 patients belonging to this group since polyps or carcinoma was found in their colorectal tract during colonoscopy. The histopathology reports confirm the group classification. Total 36 polyps' AF spectra and 9 carcinoma' AF spectra were detected from 25 patients of the abnormal group during their regular endoscopy examination. The intensity ratios RI-680/I-500 and RI-630/I-500 of polyps/cancerous AF spectra and intensity ratios of corresponding normal colorectal AF spectra were calculated. Two critical intensity ratios for separating the AF intensity ratios RI-680/I-500 and RI-630/I-500 of normal and abnormal colorectal tissues were defined as 0.5 and 0.6 respectively. Using the critical intensity ratio values, 48 "normal" group patients' rectums were checked via the LIAF detection system. There were 20 patients (41.7%) whose AF spectra of colorectal tract mucosa belonging to abnormal spectra. However, these 20 patients had not been found under white light via traditional endoscopy. For small diseased area like small plat polyp disease and carcinoma, it was very difficult to identify under white light by endoscopy. However, the LIAF spectra technique and AF intensity ratio algorithm was able to detect these kinds of abnormal area earlier than traditional endoscopy. Using this algorithm, it is able to identify the onset of abnormal tissue growth during real-time clinical endoscope examination.

Reduced background autofluorescence for cell imaging using nanodiamonds and lanthanide chelates.

PubMed

Cordina, Nicole M; Sayyadi, Nima; Parker, Lindsay M; Everest-Dass, Arun; Brown, Louise J; Packer, Nicolle H

2018-03-14

Bio-imaging is a key technique in tracking and monitoring important biological processes and fundamental biomolecular interactions, however the interference of background autofluorescence with targeted fluorophores is problematic for many bio-imaging applications. This study reports on two novel methods for reducing interference with cellular autofluorescence for bio-imaging. The first method uses fluorescent nanodiamonds (FNDs), containing nitrogen vacancy centers. FNDs emit at near-infrared wavelengths typically higher than most cellular autofluorescence; and when appropriately functionalized, can be used for background-free imaging of targeted biomolecules. The second method uses europium-chelating tags with long fluorescence lifetimes. These europium-chelating tags enhance background-free imaging due to the short fluorescent lifetimes of cellular autofluorescence. In this study, we used both methods to target E-selectin, a transmembrane glycoprotein that is activated by inflammation, to demonstrate background-free fluorescent staining in fixed endothelial cells. Our findings indicate that both FND and Europium based staining can improve fluorescent bio-imaging capabilities by reducing competition with cellular autofluorescence. 30 nm nanodiamonds coated with the E-selectin antibody was found to enable the most sensitive detective of E-selectin in inflamed cells, with a 40-fold increase in intensity detected.

Denaturing of single electrospun fibrinogen fibers studied by deep ultraviolet fluorescence microscopy.

PubMed

Kim, Jeongyong; Song, Hugeun; Park, Inho; Carlisle, Christine R; Bonin, Keith; Guthold, Martin

2011-03-01

Deep ultraviolet (DUV) microscopy is a fluorescence microscopy technique to image unlabeled proteins via the native fluorescence of some of their amino acids. We constructed a DUV fluorescence microscope, capable of 280 nm wavelength excitation by modifying an inverted optical microscope. Moreover, we integrated a nanomanipulator-controlled micropipette into this instrument for precise delivery of picoliter amounts of fluid to selected regions of the sample. In proof-of-principle experiments, we used this instrument to study, in situ, the effect of a denaturing agent on the autofluorescence intensity of single, unlabeled, electrospun fibrinogen nanofibers. Autofluorescence emission from the nanofibers was excited at 280 nm and detected at ∼350 nm. A denaturant solution was discretely applied to small, select sections of the nanofibers and a clear local reduction in autofluorescence intensity was observed. This reduction is attributed to the dissolution of the fibers and the unfolding of proteins in the fibers. Copyright © 2010 Wiley-Liss, Inc.

Near-infrared autofluorescence spectroscopy of in vivo soft tissue sarcomas

PubMed Central

Nguyen, John Quan; Gowani, Zain; O'Connor, Maggie; Pence, Isaac; Nguyen, The-Quyen; Holt, Ginger; Mahadevan-Jansen, Anita

2016-01-01

Soft tissue sarcomas (STS) are a rare and heterogeneous group of malignant tumors that are often treated via surgical resection. Inadequate resection can lead to local recurrence and decreased survival rates. In this study, we investigate the hypothesis that near-infrared (NIR) autofluorescence can be utilized for tumor margin analysis by differentiating STS from the surrounding normal tissue. Intraoperative in vivo measurements were acquired from 30 patients undergoing STS resection and were characterized to differentiate between normal tissue and STS. Overall, normal muscle and fat were observed to have the highest and lowest autofluorescence intensities, respectively, with STS falling in between. With the exclusion of well-differentiated liposarcomas, the algorithm's accuracy for classifying muscle, fat, and STS was 93%, 92%, and 88%, respectively. These findings suggest that NIR autofluorescence spectroscopy has potential as a rapid and nondestructive surgical guidance tool that can inform surgeons of suspicious margins in need of immediate re-excision. PMID:26625035

Evaluation of skin pathologies by RGB autofluorescence imaging

NASA Astrophysics Data System (ADS)

Lihachev, Alexey; Plorina, Emilija V.; Derjabo, Alexander; Lange, Marta; Lihacova, Ilze

2017-12-01

A clinical trial on autofluorescence imaging of malignant and non-malignant skin pathologies comprising 32 basal cell carcinomas (BCC), 4 malignant melanomas (MM), 1 squamous cell carcinoma (SCC), 89 nevi, 14 dysplastic nevi, 20 hemangiomas, 23 seborrheic keratoses, 4 hyperkeratoses, 3 actinic keratoses, 3 psoriasis, 1 dematitis, 2 dermatofibromas, 5 papillofibromas, 12 lupus erythematosus, 7 purpura, 6 bruises, 5 freckles, 3 fungal infections, 1 burn, 1 tattoo, 1 age spot, 1 vitiligo, 32 postoperative scars, 8 post cream therapy BCCs, 4 post radiation therapy scars, 2 post laser therapy scars, 1 post freezing scar as well as 114 reference images of healthy skin was performed. The sequence of autofluorescence images of skin pathologies were recorded by smartphone RGB camera under continuous 405 nm LED excitation during 20 seconds with 0.5 fps. Obtained image sequences further were processed with subsequent extraction of autofluorescence intensity and photobleaching parameters.

Fluorescence dynamics of human epidermis (ex vivo) and skin (in vivo)

NASA Astrophysics Data System (ADS)

Salomatina, Elena V.; Pravdin, Alexander B.

2003-10-01

The temporal behavior of autofluorescence of human skin and epidermis under continuous UV-irradiation has been studied. Fluorescence spectra and kinetic curves of fluorescence intensity have been obtained. The fluorescence intensity recovery after dark period also has been examined. The vitiligo skin and epidermis were used for comparing their spectra with reflectance and fluorescence spectra of healthy skin. The epidermal samples were prepared using surface epidermis stripping technique. It has been concluded that fluorophores being undergone the UVA photobleaching are actually present in epidermal layer, and immediate pigment darkening does contribute, no less than a half of magnitude, to the autofluorescence decrease under continuous UVA irradiation.

Scanning Laser Ophthalmoscope Measurement of Local Fundus Reflectance and Autofluorescence Changes Arising from Rhodopsin Bleaching and Regeneration

PubMed Central

Morgan, Jessica I. W.; Pugh, Edward N.

2013-01-01

Purpose. We measured the bleaching and regeneration kinetics of rhodopsin in the living human eye with two-wavelength, wide-field scanning laser ophthalmoscopy (SLO), and investigated the effect of rhodopsin bleaching on autofluorescence intensity. Methods. The retina was imaged with an Optos P200C SLO by its reflectance of 532 and 633 nm light, and its autofluorescence excited by 532 nm light, before and after exposure to lights calibrated to bleach rhodopsin substantially. Bleaching was confined to circular retinal regions of 4.8° visual angle located approximately 16° superotemporal and superonasal to fixation. Images were captured as 12-bit tiff files and postprocessed to extract changes in reflectance and autofluorescence. Results. At the locus of bleaching transient increases in reflectance of the 532 nm, but not the 633 nm beam were observed readily and quantified. A transient increase in autofluorescence also occurred. The action spectrum, absolute sensitivity, and recovery of the 532 nm reflectance increase were consistent with previous measurements of human rhodopsin's spectral sensitivity, photosensitivity, and regeneration kinetics. The autofluorescence changes closely tracked the changes in rhodopsin density. Conclusions. The bleaching and regeneration kinetics of rhodopsin can be measured locally in the human retina with a widely available SLO. The increased autofluorescence excited by 532 nm light upon bleaching appears primarily due to transient elimination of rhodopsin's screening of autofluorescent fluorochromes in the RPE. The spatially localized measurement with a widely available SLO of rhodopsin, the most abundant protein in the retina, could be a valuable adjunct to retinal health assessment. PMID:23412087

Scanning laser ophthalmoscope measurement of local fundus reflectance and autofluorescence changes arising from rhodopsin bleaching and regeneration.

PubMed

Morgan, Jessica I W; Pugh, Edward N

2013-03-01

We measured the bleaching and regeneration kinetics of rhodopsin in the living human eye with two-wavelength, wide-field scanning laser ophthalmoscopy (SLO), and investigated the effect of rhodopsin bleaching on autofluorescence intensity. The retina was imaged with an Optos P200C SLO by its reflectance of 532 and 633 nm light, and its autofluorescence excited by 532 nm light, before and after exposure to lights calibrated to bleach rhodopsin substantially. Bleaching was confined to circular retinal regions of 4.8° visual angle located approximately 16° superotemporal and superonasal to fixation. Images were captured as 12-bit tiff files and postprocessed to extract changes in reflectance and autofluorescence. At the locus of bleaching transient increases in reflectance of the 532 nm, but not the 633 nm beam were observed readily and quantified. A transient increase in autofluorescence also occurred. The action spectrum, absolute sensitivity, and recovery of the 532 nm reflectance increase were consistent with previous measurements of human rhodopsin's spectral sensitivity, photosensitivity, and regeneration kinetics. The autofluorescence changes closely tracked the changes in rhodopsin density. The bleaching and regeneration kinetics of rhodopsin can be measured locally in the human retina with a widely available SLO. The increased autofluorescence excited by 532 nm light upon bleaching appears primarily due to transient elimination of rhodopsin's screening of autofluorescent fluorochromes in the RPE. The spatially localized measurement with a widely available SLO of rhodopsin, the most abundant protein in the retina, could be a valuable adjunct to retinal health assessment.

Fundus autofluorescence and the bisretinoids of retina.

PubMed

Sparrow, Janet R; Wu, Yalin; Nagasaki, Takayuki; Yoon, Kee Dong; Yamamoto, Kazunori; Zhou, Jilin

2010-11-01

Imaging of the human fundus of the eye with excitation wavelengths in the visible spectrum reveals a natural autofluorescence, that in a healthy retina originates primarily from the bisretinoids that constitute the lipofuscin of retinal pigment epithelial (RPE) cells. Since the intensity and distribution of fundus autofluorescence is altered in the presence of retinal disease, we have examined the fluorescence properties of the retinal bisretinoids with a view to aiding clinical interpretations. As is also observed for fundus autofluorescence, fluorescence emission from RPE lipofuscin was generated with a wide range of exciting wavelengths; with increasing excitation wavelength, the emission maximum shifted towards longer wavelengths and spectral width was decreased. These features are consistent with fluorescence generation from a mixture of compounds. While the bisretinoids that constitute RPE lipofuscin all fluoresced with maxima that were centered around 600 nm, fluorescence intensities varied when excited at 488 nm, the excitation wavelength utilized for fundus autofuorescence imaging. For instance the fluorescence efficiency of the bisretinoid A2-dihydropyridine-phosphatidylethanolamine (A2-DHP-PE) was greater than A2E and relative to both of the latter, all-trans-retinal dimer-phosphatidylethanolamine was weakly fluorescent. On the other hand, certain photooxidized forms of the bisretinoids present in both RPE and photoreceptor cells were more strongly fluorescent than the parent compound. We also sought to evaluate whether diffuse puncta of autofluorescence observed in some retinal disorders of monogenic origin are attributable to retinoid accumulation. However, two retinoids of the visual cycle, all-trans-retinyl ester and all-trans-retinal, did not exhibit fluorescence at 488 nm excitation.

In vivo real-time recording of UV-induced changes in the autofluorescence of a melanin-containing fungus using a micro-spectrofluorimeter and a low-cost webcam.

PubMed

Raimondi, V; Agati, G; Cecchi, G; Gomoiu, I; Lognoli, D; Palombi, L

2009-12-07

An optical epifluorescence microscope, coupled to a CCD camera, a standard webcam and a microspectrofluorimeter, are used to record in vivo real-time changes in the autofluorescence of spores and hyphae in Aspergillus niger, a fungus containing melanin, while exposed to UV irradiation. The results point out major changes in both signal intensity and the spectral shape of the autofluorescence signal after only few minutes of exposure, and can contribute to the interpretation of data obtained with other fluorescence techniques, including those, such as GPF labeling, in which endogenous fluorophores constitute a major disturbance.

FUNDUS AUTOFLUORESCENCE LIFETIMES AND CENTRAL SEROUS CHORIORETINOPATHY.

PubMed

Dysli, Chantal; Berger, Lieselotte; Wolf, Sebastian; Zinkernagel, Martin S

2017-11-01

To quantify retinal fluorescence lifetimes in patients with central serous chorioretinopathy (CSC) and to identify disease specific lifetime characteristics over the course of disease. Forty-seven participants were included in this study. Patients with central serous chorioretinopathy were imaged with fundus photography, fundus autofluorescence, optical coherence tomography, and fluorescence lifetime imaging ophthalmoscopy (FLIO) and compared with age-matched controls. Retinal autofluorescence was excited using a 473-nm blue laser light and emitted fluorescence light was detected in 2 distinct wavelengths channels (498-560 nm and 560-720 nm). Clinical features, mean retinal autofluorescence lifetimes, autofluorescence intensity, and corresponding optical coherence tomography (OCT) images were further analyzed. Thirty-five central serous chorioretinopathy patients with a mean visual acuity of 78 ETDRS letters (range, 50-90; mean Snellen equivalent: 20/32) and 12 age-matched controls were included. In the acute stage of central serous chorioretinopathy, retinal fluorescence lifetimes were shortened by 15% and 17% in the respective wavelength channels. Multiple linear regression analysis showed that fluorescence lifetimes were significantly influenced by the disease duration (P < 0.001) and accumulation of photoreceptor outer segments (P = 0.03) but independent of the presence or absence of subretinal fluid. Prolonged central macular autofluorescence lifetimes, particularly in eyes with retinal pigment epithelial atrophy, were associated with poor visual acuity. This study establishes that autofluorescence lifetime changes occurring in central serous chorioretinopathy exhibit explicit patterns which can be used to estimate perturbations of the outer retinal layers with a high degree of statistical significance.

Quantitative Fundus Autofluorescence in Best Vitelliform Macular Dystrophy: RPE Lipofuscin is not Increased in Non-Lesion Areas of Retina

PubMed Central

Duncker, Tobias; Woods, Russell; Delori, François C.

2018-01-01

Since the lipofuscin of retinal pigment epithelial (RPE) cells has been implicated in the pathogenesis of Best vitelliform macular dystrophy, we quantified fundus autofluorescence (quantitative fundus autofluorescence, qAF) as an indirect measure of RPE lipofuscin levels. Mean non-lesion qAF was found to be within normal limits for age. By spectral domain optical coherence tomography (SD-OCT) vitelliform lesions presented as fluid-filled subretinal detachments containing reflective material. We discuss photoreceptor outer segment debris as the source of the intense fluorescence of these lesions and loss of anion channel functioning as an explanation for the bullous photoreceptor-RPE detachment. Unexplained is the propensity of the disease for central retina. PMID:26427423

Quantitative Fundus Autofluorescence in Best Vitelliform Macular Dystrophy: RPE Lipofuscin is not Increased in Non-Lesion Areas of Retina.

PubMed

Sparrow, Janet R; Duncker, Tobias; Woods, Russell; Delori, François C

2016-01-01

Since the lipofuscin of retinal pigment epithelial (RPE) cells has been implicated in the pathogenesis of Best vitelliform macular dystrophy, we quantified fundus autofluorescence (quantitative fundus autofluorescence, qAF) as an indirect measure of RPE lipofuscin levels. Mean non-lesion qAF was found to be within normal limits for age. By spectral domain optical coherence tomography (SD-OCT) vitelliform lesions presented as fluid-filled subretinal detachments containing reflective material. We discuss photoreceptor outer segment debris as the source of the intense fluorescence of these lesions and loss of anion channel functioning as an explanation for the bullous photoreceptor-RPE detachment. Unexplained is the propensity of the disease for central retina.

Application autofluorescence diagnosis method in endoscopy for investigation mucosal structure in gastrointestinal tract

NASA Astrophysics Data System (ADS)

Varlamova, Larisa; Abramov, Dmitrii; Golovin, Arsenii; Seledkina, Ekaterina

2017-05-01

One of the promising methods for early diagnosis of malignant diseases of the respiratory organs and the gastrointestinal tract (GIT) is now considered a fluorescence method. Application autofluorescence phenomenon in endoscopy allows to obtain a fluorescent image of the mucosa, which shows the difference in the intensity of the autofluorescence of healthy and the affected tissue in the green and red regions of the spectrum. The result of the work is to determine on the basis of scientific research and prototyping capabilities of creating fluorescence video endoscope and the development of fluorescent light (illuminator FLU) for videoendoscopy complex. The solution of this problem is based on the method of studying biological objects in lifetime condition.

High-throughput measurements of the optical redox ratio using a commercial microplate reader.

PubMed

Cannon, Taylor M; Shah, Amy T; Walsh, Alex J; Skala, Melissa C

2015-01-01

There is a need for accurate, high-throughput, functional measures to gauge the efficacy of potential drugs in living cells. As an early marker of drug response in cells, cellular metabolism provides an attractive platform for high-throughput drug testing. Optical techniques can noninvasively monitor NADH and FAD, two autofluorescent metabolic coenzymes. The autofluorescent redox ratio, defined as the autofluorescence intensity of NADH divided by that of FAD, quantifies relative rates of cellular glycolysis and oxidative phosphorylation. However, current microscopy methods for redox ratio quantification are time-intensive and low-throughput, limiting their practicality in drug screening. Alternatively, high-throughput commercial microplate readers quickly measure fluorescence intensities for hundreds of wells. This study found that a commercial microplate reader can differentiate the receptor status of breast cancer cell lines (p < 0.05) based on redox ratio measurements without extrinsic contrast agents. Furthermore, microplate reader redox ratio measurements resolve response (p < 0.05) and lack of response (p > 0.05) in cell lines that are responsive and nonresponsive, respectively, to the breast cancer drug trastuzumab. These studies indicate that the microplate readers can be used to measure the redox ratio in a high-throughput manner and are sensitive enough to detect differences in cellular metabolism that are consistent with microscopy results.

Depth-dependent autofluorescence photobleaching using 325, 473, 633, and 785 nm of porcine ear skin ex vivo

NASA Astrophysics Data System (ADS)

Schleusener, Johannes; Lademann, Jürgen; Darvin, Maxim E.

2017-09-01

Autofluorescence photobleaching describes the decrease of fluorescence intensity of endogenous fluorophores in biological tissue upon light irradiation. The origin of autofluorescence photobleaching is not fully understood. In the skin, the spatial distribution of various endogenous fluorophores varies within the skin layers. Most endogenous fluorophores are excited in the ultraviolet and short visible wavelength range, and only a few, such as porphyrins (red) and melanin (near-infrared), are excited at longer wavelengths. The excitation wavelength- and depth-dependent irradiation of skin will therefore excite different fluorophores, which will likely influence the photobleaching characteristics. The autofluorescence photobleaching of porcine ear skin has been measured ex vivo using 325, 473, 633, and 785 nm excitation at different skin depths from the surface to the dermis at 150 μm. Confocal Raman microscopes were used to achieve sufficient spatial resolution of the measurements. The autofluorescence area under the curve was measured for 21 consecutive acquisitions of 15 s. In all cases, the photobleaching follows a two-exponential decay function approximated by nonlinear regression. The results show that photobleaching can be applied to improve the signal-to-noise ratio in Raman spectroscopy for all of the applied excitation wavelengths and skin depths.

FUNDUS AUTOFLUORESCENCE LIFETIMES AND CENTRAL SEROUS CHORIORETINOPATHY

PubMed Central

Dysli, Chantal; Berger, Lieselotte; Wolf, Sebastian

2017-01-01

Purpose: To quantify retinal fluorescence lifetimes in patients with central serous chorioretinopathy (CSC) and to identify disease specific lifetime characteristics over the course of disease. Methods: Forty-seven participants were included in this study. Patients with central serous chorioretinopathy were imaged with fundus photography, fundus autofluorescence, optical coherence tomography, and fluorescence lifetime imaging ophthalmoscopy (FLIO) and compared with age-matched controls. Retinal autofluorescence was excited using a 473-nm blue laser light and emitted fluorescence light was detected in 2 distinct wavelengths channels (498–560 nm and 560–720 nm). Clinical features, mean retinal autofluorescence lifetimes, autofluorescence intensity, and corresponding optical coherence tomography (OCT) images were further analyzed. Results: Thirty-five central serous chorioretinopathy patients with a mean visual acuity of 78 ETDRS letters (range, 50–90; mean Snellen equivalent: 20/32) and 12 age-matched controls were included. In the acute stage of central serous chorioretinopathy, retinal fluorescence lifetimes were shortened by 15% and 17% in the respective wavelength channels. Multiple linear regression analysis showed that fluorescence lifetimes were significantly influenced by the disease duration (P < 0.001) and accumulation of photoreceptor outer segments (P = 0.03) but independent of the presence or absence of subretinal fluid. Prolonged central macular autofluorescence lifetimes, particularly in eyes with retinal pigment epithelial atrophy, were associated with poor visual acuity. Conclusion: This study establishes that autofluorescence lifetime changes occurring in central serous chorioretinopathy exhibit explicit patterns which can be used to estimate perturbations of the outer retinal layers with a high degree of statistical significance. PMID:28099314

Nature of autofluorescence in human serum albumin under its native, unfolding and digested forms

NASA Astrophysics Data System (ADS)

Manjunath, S.; Rao, Bola Sadashiva Satish; Satyamoorthy, Kapaettu; Mahato, Krishna Kishore

2014-02-01

Autofluorescence characteristics of human serum albumin (HSA) are highly sensitive to its local environment. Identification and characterization of the proteins in normal and disease conditions may have great clinical implications. Aim of the present study was to understand how autofluorescence properties of HSA varies with denaturation under urea (3.0M, 6.0M, 9.0M) and guanidine hydrochloride (GnHCl) (2.0M, 4.0M, 6.0M) as well as digestion with trypsin. Towards this, we have recorded the corresponding autofluorescence spectra of HSA at 281nm laser excitation and compared the outcomes. Although, HSA contains 1 tryptophan and 17 tyrosine residues, it has shown intense autofluorescence due to tryptophan as compared to the tyrosine in native form, which may be due to the fluorescence resonance energy transfer (FRET) from tyrosine to tryptophan. As the unfolding progresses in denatured and digested forms of the protein, a clear increase in tyrosine fluorescence as compared to tryptophan was observed, which may be due to the increase of tryptophan - tyrosine separation disturbing the FRET between them resulting in differences in the overall autofluorescence properties. The decrease in tryptophan fluorescence of around 17% in urea denatured, 32% in GnHCl denatured and 96% in tryptic digested HSA was observed as compared to its native form. The obtained results show a clear decrease in FRET between tyrosine and tryptophan residues with the progression of unfolding and urea seems to be less efficient than GnHCl in unfolding of HSA. These results demonstrate the potential of autofluorescence in characterizing proteins in general and HSA in particular.

Skin autofluorescence as a marker of cardiovascular risk in children with chronic kidney disease.

PubMed

Makulska, Irena; Szczepańska, Maria; Drożdż, Dorota; Polak-Jonkisz, Dorota; Zwolińska, Danuta

2013-01-01

We examined skin autofluorescence (sAF) in chronic kidney disease children (CKD) in relation to renal function and dialysis modality. Twenty children on hemodialysis (HD), 20 on peritoneal dialysis (PD), 36 treated conservatively, and 26 healthy subjects were enrolled into the study. In all children sAF, pulse-wave velocity indexed to height (PWV/ht), left ventricular mass index (LVMI), blood pressure (BP), serum lipid profile, phosphate (P), calcium (Ca), and homocysteine were measured. sAF was significantly elevated in CKD groups vs. controls and was significantly associated with PWV/ht, LVMI, BP, P, Ca × P product and homocysteine. sAF in HD and PD groups was positively correlated with dialysis vintage, and in the predialysis group negatively correlated with glomerular filtration rate (eGFR). Multiple regression analysis showed significant association of sAF with LVMI and P in the CKD patient group, and with dialysis treatment duration and BP in dialyzed children. In CKD children, tissue accumulation of advanced glycation end-products (AGEs) was observed. This was aggravated as eGFR declined and was related to early cardiovascular changes and some biochemical cardiovascular disease (CVD) risk markers. sAF as a non-invasive method may be a useful tool for identification of a clinical risk factors of cardiovascular disease in CKD children.

Carbonyl-based blue autofluorescence of proteins and amino acids

PubMed Central

Niyangoda, Chamani; Miti, Tatiana; Breydo, Leonid; Uversky, Vladimir

2017-01-01

Intrinsic protein fluorescence is inextricably linked to the near-UV autofluorescence of aromatic amino acids. Here we show that a novel deep-blue autofluorescence (dbAF), previously thought to emerge as a result of protein aggregation, is present at the level of monomeric proteins and even poly- and single amino acids. Just as its aggregation-related counterpart, this autofluorescence does not depend on aromatic residues, can be excited at the long wavelength edge of the UV and emits in the deep blue. Differences in dbAF excitation and emission peaks and intensities from proteins and single amino acids upon changes in solution conditions suggest dbAF’s sensitivity to both the chemical identity and solution environment of amino acids. Autofluorescence comparable to dbAF is emitted by carbonyl-containing organic solvents, but not those lacking the carbonyl group. This implicates the carbonyl double bonds as the likely source for the autofluorescence in all these compounds. Using beta-lactoglobulin and proline, we have measured the molar extinction coefficients and quantum yields for dbAF in the monomeric state. To establish its potential utility in monitoring protein biophysics, we show that dbAF emission undergoes a red-shift comparable in magnitude to tryptophan upon thermal denaturation of lysozyme, and that it is sensitive to quenching by acrylamide. Carbonyl dbAF therefore provides a previously neglected intrinsic optical probe for investigating the structure and dynamics of amino acids, proteins and, by extension, DNA and RNA. PMID:28542206

Longitudinal evaluation of patients with oral potentially malignant disorders using optical imaging and spectroscopy

NASA Astrophysics Data System (ADS)

Schwarz, Richard A.; Pierce, Mark C.; Mondrik, Sharon; Gao, Wen; Quinn, Mary K.; Bhattar, Vijayashree; Williams, Michelle D.; Vigneswaran, Nadarajah; Gillenwater, Ann M.; Richards-Kortum, Rebecca

2012-02-01

Dysplastic and cancerous alterations in oral tissue can be detected noninvasively in vivo using optical techniques including autofluorescence imaging, high-resolution imaging, and spectroscopy. Interim results are presented from a longitudinal study in which optical imaging and spectroscopy were used to evaluate the progression of lesions over time in patients at high risk for development of oral cancer. Over 100 patients with oral potentially malignant disorders have been enrolled in the study to date. Areas of concern in the oral cavity are measured using widefield autofluorescence imaging and depth-sensitive optical spectroscopy during successive clinical visits. Autofluorescence intensity patterns and autofluorescence spectra are tracked over time and correlated with clinical observations. Patients whose lesions progress and who undergo surgery are also measured in the operating room immediately prior to surgery using autofluorescence imaging and spectroscopy, with the addition of intraoperative high-resolution imaging to characterize nuclear size, nuclear crowding, and tissue architecture at selected sites. Optical measurements are compared to histopathology results from biopsies and surgical specimens collected from the measured sites. Autofluorescence imaging and spectroscopy measurements are continued during post-surgery followup visits. We examined correlations between clinical impression and optical classification over time with an average followup period of 4 months. The data collected to date suggest that multimodal optical techniques may aid in noninvasive monitoring of the progression of oral premalignant lesions, biopsy site selection, and accurate delineation of lesion extent during surgery.

Noncontact point spectroscopy guided by two-channel fluorescence imaging in a hamster cheek pouch model

NASA Astrophysics Data System (ADS)

Yang, Victor X.; Yeow, Jenny; Lilge, Lothar D.; Kost, James; Mang, Thomas S.; Wilson, Brian C.

1999-07-01

A system for in vivo, fluorescence image-guided, non-contact point fluorescence spectroscopy is presented. A 442 nm HeCd laser is used as the fluorescence excitation source. An intensified CCD serves as the detector for both imaging and spectroscopy, on which two regions of 300 X 300 pixels were used for green (500 +/- 18 nm) and red (630 +/- 18 nm) imaging channels, and a strip of 600 X 120 pixels are used for emission spectroscopy (450 - 750 nm). At a working distance of 40 mm, the system has a spatial resolution of 0.16 mm and a spectral resolution of 5 nm. System performance is demonstrated in a carcinogenesis model in hamsters, where tumors were induced by painting DMBA in the cheek pouch. Autofluorescence and Photofrin-induced fluorescence measurements were performed every 2 weeks during the 18 weeks of tumor induction. Punch biopsies on selected animals were taken for histological staging. The results show that autofluorescence fluorescence can distinguish dysplasia from normal mucosal tissue model, utilizing the peak red intensity (or the red-to-green intensity ratio). Photofrin-induced fluorescence was superior to autofluorescence for differentiating high grade dysplasia from invasive cancer.

Discrimination and quantification of autofluorescence spectra of human lung cells

NASA Astrophysics Data System (ADS)

Rahmani, Mahya; Khani, Mohammad Mehdi; Khazaei Koohpar, Zeinab; Molik, Paria

2016-10-01

To study laser-induced autofluorescence spectroscopy of the human lung cell line, we evaluated the native fluorescence properties of cancer QU-DB and normal MRC-5 human lung cells during continuous exposure to 405 nm laser light. Two emission bands centered at ~470 nm and ~560 nm were observed. These peaks are most likely attributable to mitochondrial fluorescent reduced nicotinamide adenine dinucleotide and riboflavin fluorophores, respectively. This article highlights lung cell autofluorescence characterization and signal discrimination by collective investigation of different spectral features. The absolute intensity, the spectral shape factor or redox ratio, the full width of half-maximum and the full width of quarter maximum was evaluated. Moreover, the intensity ratio, the area under the peak and the area ratio as a contrast factor for normal and cancerous cells were also calculated. Among all these features it seems that the contrast factor precisely and significantly discriminates the spectral differences of normal and cancerous lung cells. On the other hand, the relative quantum yield for both cell types were found by comparing the quantum yield of an unknown compound with known fluorescein sodium as a reference solution.

Autofluorescence Lifetimes in Geographic Atrophy in Patients With Age-Related Macular Degeneration.

PubMed

Dysli, Chantal; Wolf, Sebastian; Zinkernagel, Martin S

2016-05-01

To investigate fluorescence lifetime characteristics in patients with geographic atrophy (GA) in eyes with age-related macular degeneration and to correlate the measurements with clinical data and optical coherence tomography (OCT) findings. Patients with GA were imaged with a fluorescence lifetime imaging ophthalmoscope. Retinal autofluorescence lifetimes were measured in a short and a long spectral channel (498-560 nm and 560-720 nm). Mean retinal fluorescence lifetimes were analyzed within GA and the surrounding retina, and data were correlated with best corrected visual acuity and OCT measurements. Fluorescence lifetime maps of 41 eyes of 41 patients (80 ± 7 years) with GA were analyzed. Mean lifetimes within areas of atrophy were prolonged by 624 ± 276 ps (+152%) in the short spectral channel and 418 ± 186 ps (+83%) in the long spectral channel compared to the surrounding tissue. Autofluorescence lifetime abnormalities in GA occurred with particular patterns, similar to those seen in fundus autofluorescence intensity images. Within the fovea short mean autofluorescence lifetimes were observed, presumably representing macular pigment. Short lifetimes were preserved even in the absence of foveal sparing but were decreased in patients with advanced retinal atrophy in OCT. Short lifetimes in the fovea correlated with better best corrected visual acuity in both spectral channels. This study established that autofluorescence lifetime changes in GA present with explicit patterns. We hypothesize that the short lifetimes seen within the atrophy may be used to estimate damage induced by atrophy and to monitor disease progression in the context of natural history or interventional therapeutic studies.

Photoreceptor cells as a source of fundus autofluorescence in recessive Stargardt disease.

PubMed

Paavo, Maarjaliis; Lee, Winston; Allikmets, Rando; Tsang, Stephen; Sparrow, Janet R

2018-04-27

Bisretinoid fluorophores form in photoreceptor outer segments from nonenzymatic reactions of vitamin A aldehyde. The short-wavelength autofluorescence (SW-AF) of fundus flecks in recessive Stargardt disease (STGD1) suggests a connection to these fluorophores. Through multimodal imaging, we sought to elucidate this link. Flecks observed in SW-AF images often colocalized with foci exhibiting reduced or absent near-infrared autofluorescence signal, the source of which is melanin in retinal pigment epithelial (RPE) cells. With serial imaging, changes in near-infrared autofluorescence (NIR-AF) preceded the onset of fleck hyperautofluorescence in SW-AF images and fleck profiles in NIR-AF images tended to be larger. Flecks in SW-AF and NIR-AF images also corresponded to hyperreflective lesions traversing photoreceptor-attributable bands in horizontal SD-OCT scans. The hyperreflective lesions interrupted adjacent OCT reflectivity bands and were associated with thinning of the outer nuclear layer. These SD-OCT findings are attributable to photoreceptor cell degeneration. Progressive increases and decreases in the SW-AF intensity of flecks were evident in color-coded quantitative fundus autofluorescence maps. In some cases, flecks appeared to spread radially from the fovea to approximately 8° of eccentricity, beyond which a circumferential spread characterized the distribution. Since the NIR-AF signal is derived from melanin and loss of this autofluorescence is indicative of RPE atrophy, the SW-AF of flecks cannot be accounted for by bisretinoid lipofuscin in RPE. Instead, we suggest that the bisretinoid serving as the source of the SW-AF signal, resides in photoreceptors, the cell that is also the site of bisretinoid synthesis. © 2018 Wiley Periodicals, Inc.

Time-resolved autofluorescence imaging of human donor retina tissue from donors with significant extramacular drusen.

PubMed

Schweitzer, Dietrich; Gaillard, Elizabeth R; Dillon, James; Mullins, Robert F; Russell, Stephen; Hoffmann, Birgit; Peters, Sven; Hammer, Martin; Biskup, Christoph

2012-06-08

Time and spectrally resolved measurements of autofluorescence have the potential to monitor metabolism at the cellular level. Fluorophores that emit with the same fluorescence intensity can be discriminated from each other by decay time of fluorescence intensity after pulsed excitation. We performed time-resolved autofluorescence measurements on fundus samples from a donor with significant extramacular drusen. Tissue sections from two human donors were prepared and imaged with a laser scanning microscope. The sample was excited with a titanium-sapphire laser, which was tuned to 860 nm, and frequency doubled by a BBO crystal to 430 nm. The repetition rate was 76 MHz and the pulse width was 170 femtoseconds (fs). The time-resolved autofluorescence was recorded simultaneously in 16 spectral channels (445-605 nm) and bi-exponentially fitted. RPE can be discriminated clearly from Bruch's membrane, drusen, and choroidal connective tissue by fluorescence lifetime. In RPE, bright fluorescence of lipofuscin could be detected with a maximum at 510 nm and extending beyond 600 nm. The lifetime was 385 ps. Different types of drusen were found. Most of them did not contain lipofuscin and exhibited a weak fluorescence, with a maximum at 470 nm. The lifetime was 1785 picoseconds (ps). Also, brightly emitting lesions, presumably representing basal laminar deposits, with fluorescence lifetimes longer than those recorded in RPE could be detected. The demonstrated differentiation of fluorescent structures by their fluorescence decay time is important for interpretation of in vivo measurements by the new fluorescence lifetime imaging (FLIM) ophthalmoscopy on healthy subjects as well as on patients.

Laser autofluorescent spectroscopy in adrenal tumor surgery

NASA Astrophysics Data System (ADS)

Vetshev, Petr S.; Ippolitov, Leonid I.; Loschenov, Victor B.; Kazaryan, Airazat M.; Minnibaev, Marat T.; Vetshev, Sergei P.

1999-12-01

Determination of a histological type of adrenal lesion at the preoperative or intraoperative stage allows to choose the optimal volume of surgery and in the short time effectively correct the postoperative hormonal therapy. 12 patients with different adrenal tumours (3 - lightcellular adenoma, 3 - mixedcellular adenoma, 1 - darkcellular adenoma, 1 - trabecular adenoma, 1 - malignant lymphoma, 3 - aldosteroma, 1 - pheochromocytoma, including the chance of combination of mixedcellular adenoma and aldosteroma of left adrenal) were operated on. The patients' aged varied from 33 to 62 years. For the first time we made intraoperative laser autofluorescent spectroscopy (IOLAS). The laser ve1ength was 632.8 nm. We defined a autofluorescent intensity. Portable equipment was used. The duration of the procedure did not exceed 2mm. The autofluorescent peak of adrenal tissue was 1.33+/-0.05 relativistic unit (RU) at 685 nm. The autofiurescent peaks of adrenal adenomas were 1 .07 RU, 0.9-1 .15 RU, 1.7-1 .9 RU, 3.4 RU accordingly for trabecular adenoma, lightcellular adenoma, mixedcellular adenoma, darkcellular adenoma Besides greater contribution of longwave component to auflurescence is characteristic for mixecellular adenoma and especially for darkcellular adenoma. The autofiurescent peaks of aldosteroma and pheochromocytoma were accordingly 1.2-1.4 RU and 2.2 RU. Spectral distribution of intensity was like mixedcellular adenoma's one. In the case of malignant lymphoma the autofiurescence peak was 2,3 RU and we also noted displacement of maximum of autoflurescence (-15 nm, from 685 nm to 670 nm).The results of IOLAS application as a adjuvant diagnosticmethod point to promise for intraoperative rapid diagnostics of adrenal tumours.

High-throughput autofluorescence flow cytometry of breast cancer metabolism (Conference Presentation)

NASA Astrophysics Data System (ADS)

Shah, Amy T.; Cannon, Taylor M.; Higginbotham, Jim N.; Skala, Melissa C.

2016-02-01

Tumor heterogeneity poses challenges for devising optimal treatment regimens for cancer patients. In particular, subpopulations of cells can escape treatment and cause relapse. There is a need for methods to characterize tumor heterogeneity of treatment response. Cell metabolism is altered in cancer (Warburg effect), and cells use the autofluorescent cofactor NADH in numerous metabolic reactions. Previous studies have shown that microscopy measurements of NADH autofluorescence are sensitive to treatment response in breast cancer, and these techniques typically assess hundreds of cells per group. An alternative approach is flow cytometry, which measures fluorescence on a single-cell level and is attractive for characterizing tumor heterogeneity because it achieves high-throughput analysis and cell sorting in millions of cells per group. Current applications for flow cytometry rely on staining with fluorophores. This study characterizes flow cytometry measurements of NADH autofluorescence in breast cancer cells. Preliminary results indicate flow cytometry of NADH is sensitive to cyanide perturbation, which inhibits oxidative phosphorylation, in nonmalignant MCF10A cells. Additionally, flow cytometry is sensitive to higher NADH intensity for HER2-positive SKBr3 cells compared with triple-negative MDA-MB-231 cells. These results agree with previous microscopy studies. Finally, a mixture of SKBr3 and MDA-MB-231 cells were sorted into each cell type using NADH intensity. Sorted cells were cultured, and microscopy validation showed the expected morphology for each cell type. Ultimately, flow cytometry could be applied to characterize tumor heterogeneity based on treatment response and sort cell subpopulations based on metabolic profile. These achievements could enable individualized treatment strategies and improved patient outcomes.

UTILIZATION OF FUNDUS AUTOFLUORESCENCE, SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY, AND ENHANCED DEPTH IMAGING IN THE CHARACTERIZATION OF BIETTI CRYSTALLINE DYSTROPHY IN DIFFERENT STAGES.

PubMed

Li, Qian; Li, Yang; Zhang, Xiaohui; Xu, Zhangxing; Zhu, Xiaoqing; Ma, Kai; She, Haicheng; Peng, Xiaoyan

2015-10-01

To characterize Bietti crystalline dystrophy (BCD) in different stages using multiple imaging modalities. Sixteen participants clinically diagnosed as BCD were included in the retrospective study and were categorized into 3 stages according to fundus photography. Eleven patients were genetically confirmed. Fundus autofluorescence, spectral domain optical coherence tomography, and enhanced depth imaging features of BCD were analyzed. On fundus autofluorescence, the abnormal autofluorescence was shown to enlarge in area and decrease in intensity with stages. Using spectral domain optical coherence tomography, the abnormalities in Stage 1 were observed to localize in outer retinal layers, whereas in Stage 2 and Stage 3, more extensive retinal atrophy was seen. In enhanced depth imaging, the subfoveal choroidal layers were delineated clearly in Stage 1; in Stage 2, destructions were primarily found in the choriocapillaris with associated alterations in the outer vessels; Stage 3 BCD displayed severe choroidal thinning. Choroidal neovascularization and macular edema were exhibited with high incidence. IVS6-8del17bp/inGC of the CYP4V2 gene was the most common mutant allele. Noninvasive fundus autofluorescence, spectral domain optical coherence tomography, and enhanced depth imaging may help to characterize the chorioretinal pathology of BCD at different degrees, and therefore, we propose staging of BCD depending on those methods. Physicians should be cautious of the vision-threatening complications of the disease.

Detection of airway ischaemic damage after lung transplantation by using autofluorescence imaging bronchoscopy.

PubMed

Iga, Norichika; Oto, Takahiro; Okada, Masanori; Harada, Masaaki; Nishikawa, Hitoshi; Miyoshi, Kentaroh; Otani, Shinji; Sugimoto, Seiichiro; Yamane, Masaomi; Toyooka, Shinichi; Miyoshi, Shinichiro

2014-03-01

Airway complications related to ischaemia are a major cause of morbidity after lung transplantation. Early detection of airway ischaemia and optimal management of the anastomotic site could reduce the risk of airway complications. Autofluorescence imaging (AFI) bronchoscopy has been increasingly recognized as an effective technique for detecting abnormal mucosal thickening. The aim of this study was to investigate whether AFI bronchoscopy can facilitate the detection of airway ischaemic damage in lung transplant patients. Twenty Landrace pigs were used to create a tracheal autotransplantation model. A four-ring length of trachea was excised and implanted orthotopically. The tracheal autograft was observed on postoperative days 0, 2, 4 and 7 with AFI bronchoscopy. The extent and origin of graft autofluorescence were examined using histology and measured according to fluorescence intensity. The lesions on the tracheal autografts appeared as bright green fluorescence on AFI bronchoscopy. On confocal fluorescence microscopy, high-intensity green fluorescence was observed in the elastin fibre layer of the submucosa. The fluorescence intensity of elastin was significantly higher in the graft showing fluorescence than the graft that did not show fluorescence and that at the control site. Bright green fluorescence was seen in an elastin fibre layer in the submucosa, which was likely a result of epithelial sloughing. There is a close relationship between the bright green fluorescence pattern observed using AFI bronchoscopy and airway ischaemic damage. We conclude that AFI bronchoscopy may detect airway ischaemic damage after lung transplantation.

Characterization of corneal damage from Pseudomonas aeruginosa infection by the use of multiphoton microscopy

NASA Astrophysics Data System (ADS)

Chang, Yu-Lin; Chen, Wei-Liang; Lo, Wen; Chen, Shean-Jen; Tan, Hsin-Yuan; Dong, Chen-Yuan

2010-11-01

Using multiphoton autofluorescence (MAF) and second harmonic generation (SHG) microscopy, we investigate the morphology and the structure of the corneal epithelium and stroma collagen of bovine cornea following injection of Pseudomonas aeruginosa. We found that corneal epithelial cells are damaged and stromal collagen becoming increasingly autofluorescent with time. We also characterized infected cornea cultured for 0, 6, 12, and 24 h by quantitative ratiometric MAF to SHG index (MAFSI) analysis. MAFSI results show that the destruction of the stromal collagen corresponds to a decrease in SHG intensity and increase of MAF signal with time.

[Examination of skin autofluorescence for the determination of glycation end-products in patients on chronic hemodialysis].

PubMed

Golubev, R V; Papayan, G V; Glazunova, A A; Korosteleva, N Yu; Petrishchev, N N; Smirnov, A V

2016-01-01

To assess the results of determination of glycation end-products (GEPs) by skin autofluorescence (AF) in patients on chronic hemodialysis (HD). A device made in Russia was used to estimate skin AF intensity in 40 apparently healthy individuals and in 76 patients treated with chronic HD. While analyzing the findings, comparisons were made in both groups; a relationship between skin AF intensity and clinical and laboratory parameters was also investigated in patients on HD. The intensity of AF in the patients treated with chronic HD proved to be significantly higher than that in the control group. There was a direct correlation of the intensity of AF with age in both groups and that with the duration of dialysis treatment in patients on HD. In patients with coronary heart disease, the intensity of AF was significantly higher than in those without this condition. The intensity of AF directly correlated with the Charlson comorbidity index in the patients on HD. There were no correlations of skin AF intensity with main generally detected laboratory blood indicators, body mass index, and the nature of drug therapy in the patients on HD. Tissue GEP levels may serve as a cumulative index of metabolic stress in HD patients. The determination of GEP by measuring the intensity of skin AF may be used to assess prognosis in patients treated with chronic HD.

Macular autofluorescence in eyes with cystoid macula edema, detected with 488 nm-excitation but not with 580 nm-excitation.

PubMed

Bessho, Kenichiro; Gomi, Fumi; Harino, Seiyo; Sawa, Miki; Sayanagi, Kaori; Tsujikawa, Motokazu; Tano, Yasuo

2009-06-01

Fundus autofluorescence (AF) derives from lipofuscin in the retinal pigment epithelium (RPE). Because lipofuscin is a by-product of phagocytosis of photoreceptors by RPE, AF imaging is expected to describe some functional aspect of the retina. In this study we report distribution of AF in patients showing macular edema. Three eyes with diabetic macular edema (DME) and 11 with retinal vein occlusion (RVO), associated with macular edema (ME) were examined. ME was determined by standard fundus examination, fluorescein angiography (FA) and optical coherence tomography (OCT). AF was recorded using a Heidelberg confocal scanning laser ophthalmoscope (cSLO) with 488 nm laser exciter (488 nm-AF), and a conventional Topcon fundus camera with halogen lamp exciter and 580 nm band-pass filter (580 nm-AF). Color fundus picture, FA image and these two AF images were analyzed by superimposing all images. All subjects presented cystoid macular edema (CME) with petaloid pattern hyperfluorescence in FA. In 488 nm-AF, all eyes (100%) showed macular autofluorescence of a similar shape to that of the CME in FA. In contrast, in 580 nm-AF only one eye (7%) presented this corresponding petaloid-shaped autofluorescence. In all cases, peripheral retinal edemas did not show autofluorescence corresponding to the leakage in FA. In eyes with CME, analogous hyperautofluorescence to the CME was always observed in 488 nm-AF, while it was rarely observed in 580 nm-AF. Moreover, this CME hyperautofluorescence was only seen in the macular area. We hypothesize that autofluorescence from CME may be considered as a "pseudo" or "relative" autofluorescence, due to macular stretching following CME that may result in lateral displacement of macular pigments (MPs) and subsequent reduction of MPs density, as MPs block 488 nm-AF more intensely than 580 nm-AF. Although this phenomenon may not directly indicate change of RPE function, it may be used as a method to assess or track CME non-invasively.

Habits with killer instincts: in vivo analysis on the severity of oral mucosal alterations using autofluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Nazeer Shaiju, S.; Ariya, Saraswathy; Asish, Rajasekharan; Salim Haris, Padippurakkakath; Anita, Balan; Arun Kumar, Gupta; Jayasree, Ramapurath S.

2011-08-01

Oral habits like chewing and smoking are main causes of oral cancer, which has a higher mortality rate than many other cancer forms. Currently, the long term survival rate of oral cancer is less than 50%, as a majority of cases are detected very late. The clinician's main challenge is to differentiate among a multitude of red, white, or ulcerated lesions. Hence, new noninvasive, reliable, and fast techniques for the discrimination of oral cavity disorders are to be developed. This study includes autofluorescence spectroscopic screening of normal volunteers with and without lifestyle oral habits and patients with oral submucous fibrosis (OSF). The spectra from different sites of habitués, non-habitués, and OSF patients were analyzed using the intensity ratio, redox ratio, and linear discriminant analysis (LDA). The spectral disparities among these groups are well demonstrated in the emission regions of collagen and Flavin adenine dinucleotide. We observed that LDA gives better efficiency of classification than the intensity ratio technique. Even the differentiation of habitués and non-habitués could be well established with LDA. The study concludes that the clinical application of autofluorescence spectroscopy along with LDA, yields spontaneous screening among individuals, facilitating better patient management for clinicians and better quality of life for patients.

Time-resolvable fluorescent conjugates for the detection of pathogens in environmental samples containing autofluorescent material

NASA Astrophysics Data System (ADS)

Connally, Russell; Veal, Duncan; Piper, James A.

2003-07-01

Water is routinely monitored for environmental pathogens such a Cryptosporidium and Giardia using immunofluorescence microscopy (IFM). Autofluorescence can greatly diminish an operators capacity to resolve labeled pathogens from non-specific background. Naturally fluorescing components (autofluorophores) encountered in biological samples typically have fluorescent lifetimes (τ) of less than 100 nanoseconds and their emissions may be excluded through use of time-resolved fluorescence microscopy (TRFM). TRFM relies on the large differences in τ between autofluorescent molecules and long-lived lanthanide chelates. In TRFM, targets labeled with a time-resolvable fluorescent immunoconjugate are excited by an intense (UV) light pulse. A short delay is imposed to permit the decay of autofluorescence before capture of luminescence from the excited chelate using an image intensified CCD camera. In our experience, autofluorescence can be reduced to insignificant levels with a consequent 30-fold increase in target visibility using TRFM techniques. We report conjugation of a novel europium chelate to a monoclonal antibody specific for Giardia lamblia and use of the immunoconjugate for TRFM studies. Initial attempts to conjugate the same chelate to a monoclonal antibody directed against Cryptosporidium parvum led to poorly fluorescent constructs that were prone to denature and precipitate. We successfully conjugated BHHCT to anti-mouse polyvalent immunoglobulin and used this construct to overcome the difficulties in direct labeling of the anti-Cryptosporidium antibody. Both Giardia and Cryptosporidium were labeled using the anti-mouse protocol with a subsequent 20-fold and 6.6-fold suppression of autofluorescence respectively. A rapid protocol for conjugating and purifying the immunoconjugate was found and methods of quantifying the fluorescence to protein ratio determined. Performance of our TRFM was dependent on the quality and brightness of the immunoconjugate and optimization of the conjugation process is necessary to reap the full benefit of time-resolved techniques.

Skin autofluorescence is a predictor of cardiovascular disease in chronic kidney disease patients.

PubMed

Furuya, Fumihiko; Shimura, Hiroki; Takahashi, Kazuya; Akiyama, Daiichiro; Motosugi, Ai; Ikegishi, Yukinobu; Haraguchi, Kazutaka; Kobayashi, Tetsuro

2015-02-01

Accelerated formation and tissue accumulation of advanced glycation end products (AGEs), reflecting cumulative glycemic and oxidative stress, occurs in age-related and chronic diseases like diabetes mellitus (DM) and renal failure, and contributes to vascular damage. Skin autofluorescence (AFR), a noninvasive measurement method, reflects tissue accumulation of AGEs. AFR has been reported to be an independent predictor of mortality in Caucasian hemodialysis patients. We assessed the relationship between levels of AFR and the prevalence of cardiovascular disease (CVD), and clarified the prognostic usefulness of skin AFR levels in Asian (non-Caucasian) hemodialysis (HD) patients. AFR was measured with an autofluorescence reader in 64 HD patients. Overall and cardiovascular mortality was monitored prospectively during the 3-year follow-up. During follow-up, CVD events occurred in 21 patients. The deaths of 10 HD patients were associated with CVD. Multivariate logistic regression analyses showed that initial AFR was an independent risk factor for de novo CVD in HD patients with or without diabetes. When patients were classified on the basis of AFR tertiles, Cochran-Armitage analysis demonstrated that the highest tertile of AFR level showed an increased odds ratio for the prevalence of CVD. These findings suggest that AFR levels can be used to detect the prevalence of CVD in HD patients with or without diabetes. © 2014 The Authors. Therapeutic Apheresis and Dialysis © 2014 International Society for Apheresis.

Understanding the Biological Basis of Autofluorescence Imaging for Oral Cancer Detection: High-Resolution Fluorescence Microscopy in Viable Tissue

PubMed Central

Pavlova, Ina; Williams, Michelle; El-Naggar, Adel; Richards-Kortum, Rebecca; Gillenwater, Ann

2009-01-01

Purpose Autofluorescence imaging is increasingly used to noninvasively identify neoplastic oral cavity lesions. Improving the diagnostic accuracy of these techniques requires a better understanding of the biological basis for optical changes associated with neoplastic transformation in oral tissue. Experimental Design A total of 49 oral biopsies were considered in this study. The autofluorescence patterns of viable normal, benign, and neoplastic oral tissue were imaged using high-resolution confocal fluorescence microscopy. Results The autofluorescence properties of oral tissue vary significantly based on anatomic site and pathologic diagnosis. In normal oral tissue, most of the epithelial autofluorescence originates from the cytoplasm of cells in the basal and intermediate regions, whereas structural fibers are responsible for most of the stromal fluorescence. A strongly fluorescent superficial layer was observed in tissues from the palate and the gingiva, which contrasts with the weakly fluorescent superficial layer found in other oral sites. Upon UV excitation, benign inflammation shows decreased epithelial fluorescence, whereas dysplasia displays increased epithelial fluorescence compared with normal oral tissue. Stromal fluorescence in both benign inflammation and dysplasia drops significantly at UV and 488 nm excitation. Conclusion Imaging oral lesions with optical devices/probes that sample mostly stromal fluorescence may result in a similar loss of fluorescence intensity and may fail to distinguish benign from precancerous lesions. Improved diagnostic accuracy may be achieved by designing optical probes/devices that distinguish epithelial fluorescence from stromal fluorescence and by using excitation wavelengths in the UV range. PMID:18413830

Portable fluorescence meter with reference backscattering channel

NASA Astrophysics Data System (ADS)

Kornilin, Dmitriy V.; Grishanov, Vladimir N.; Zakharov, Valery P.; Burkov, Dmitriy S.

2016-09-01

Methods based on fluorescence and backscattering are intensively used for determination of the advanced glycation end products (AGE) concentration in the biological tissues. There are strong correlation between the AGE concentration and the severity of such diseases like diabetes, coronary heart disease and renal failure. This fact can be used for diagnostic purposes in medical applications. Only few investigations in this area can be useful for development of portable and affordable in vivo AGE meter because the most of them are oriented on using spectrometers. In this study we describe the design and the results of tests on volunteers of portable fluorescence meter based on two photodiodes. One channel of such fluorimeter is used for measurement of the autofluorescence (AF) intensity, another one - for the intensity of elastically scattered radiation, which can be used as a reference. This reference channel is proposed for normalization of the skin autofluorescence signal to the human skin photo type. The fluorimeter, that was developed is relatively compact and does not contain any expensive optical and electronic components. The experimental results prove that proposed tool can be used for the AGE estimation in human skin.

Age-related structural abnormalities in the human retina-choroid complex revealed by two-photon excited autofluorescence imaging.

PubMed

Han, Meng; Giese, Guenter; Schmitz-Valckenberg, Steffen; Bindewald-Wittich, Almut; Holz, Frank G; Yu, Jiayi; Bille, Josef F; Niemz, Markolf H

2007-01-01

The intensive metabolism of photoreceptors is delicately maintained by the retinal pigment epithelium (RPE) and the choroid. Dysfunction of either the RPE or choroid may lead to severe damage to the retina. Two-photon excited autofluorescence (TPEF) from endogenous fluorophores in the human retina provides a novel opportunity to reveal age-related structural abnormalities in the retina-choroid complex prior to apparent pathological manifestations of age-related retinal diseases. In the photoreceptor layer, the regularity of the macular photoreceptor mosaic is preserved during aging. In the RPE, enlarged lipofuscin granules demonstrate significantly blue-shifted autofluorescence, which coincides with the depletion of melanin pigments. Prominent fibrillar structures in elderly Bruch's membrane and choriocapillaries represent choroidal structure and permeability alterations. Requiring neither slicing nor labeling, TPEF imaging is an elegant and highly efficient tool to delineate the thick, fragile, and opaque retina-choroid complex, and may provide clues to the trigger events of age-related macular degeneration.

Identification of tissular origin of particles based on autofluorescence multispectral image analysis at the macroscopic scale

NASA Astrophysics Data System (ADS)

Corcel, Mathias; Devaux, Marie-Françoise; Guillon, Fabienne; Barron, Cécile

2017-06-01

Powders produced from plant materials are heterogeneous in relation to native plant heterogeneity, and during grinding, dissociation often occurred at the tissue scale. The tissue composition of powdery samples could be modified through dry fractionation diagrams and impact their end-uses properties. If tissue identification is often made on native plant structure, this characterization is not straightforward in destructured samples such powders. Taking advantage of the autofluorescence properties of cell wall components, multispectral image acquisition is envisioned to identify the tissular origin of particles. Images were acquired on maize stem sections and ground tissues isolated from the same stem by hand dissection. The variability in fluorescence intensity profiles was analysed using principal component analysis. The correspondence between fluorescence profiles and the different tissues observed in maize sections was assessed based on histology or known compositional heterogeneity. Similar variability was encountered in fluorescence profiles extracted from powder leading to the potential ability to predict tissular origin based on this autofluorescence multispectral signal.

Endoscopic tissue autofluorescence measurements in the upper aerodigestive tract and the bronchi

NASA Astrophysics Data System (ADS)

Braichotte, Daniel; Wagnieres, Georges A.; Monnier, Philippe; Savary, Jean-Francois; Bays, Roland; van den Bergh, Hubert; Chatelain, Andre

1991-11-01

A single multimode optical fiber is used to excite and collect tissue autofluorescence as well as the fluorescence of an IV-injected fluorescent tumor marker. Measurements of the relative fluorescence intensity of a tumor marker as a function of the time after IV injection permit measurement of the kinetics of this substance in tumor, normal tissue, and skin. The authors believe that these are the first measurements of this kind in patients. Furthermore, the autofluorescence spectrum generated at several excitation wavelengths in different tissues is compared, for instance in the oesophagus, the bronchi, and the tongue. The measuring system is based on an optical multichannel analyzer which measures the fluorescence excited by monochromatic radiation from a spectrally filtered Xe lamp. A correlation between the observed pharmacokinetics and tumor properties like the degree of vascularization is of fundamental importance for each selected tumor marker. Also, the results of these measurements are used for the optical detection of tumors.

Multiphoton tomography of the human eye

NASA Astrophysics Data System (ADS)

König, Karsten; Batista, Ana; Hager, Tobias; Seitz, Berthold

2017-02-01

Multiphoton tomography (MPT) is a novel label-free clinical imaging method for non-invasive tissue imaging with high spatial (300 nm) and temporal (100 ps) resolutions. In vivo optical histology can be realized due to the nonlinear excitation of endogenous fluorophores and second-harmonic generation (SHG) of collagen. Furthermore, optical metabolic imaging (OMI) is performed by two-photon autofluorescence lifetime imaging (FLIM). So far, applications of the multiphoton tomographs DermaInspect and MPTflex were limited to dermatology. Novel applications include intraoperative brain tumor imaging as well as cornea imaging. In this work we describe two-photon imaging of ex vivo human corneas unsuitable for transplantation. Furthermore, the cross-linking (CXL) process of corneal collagen based on UVA exposure and 0.1 % riboflavin was studied. The pharmacokinetics of the photosensitizer could be detected with high spatial resolution. Interestingly, an increase in the stromal autofluorescence intensity and modifications of the autofluorescence lifetimes were observed in the human corneal samples within a few days following CXL.

Light-induced damage and its diagnosis in two-photon excited autofluorescence imaging of retinal pigment epithelium cells

NASA Astrophysics Data System (ADS)

Chen, Danni; Qu, Junle; Xu, Gaixia; Zhao, Lingling; Niu, Hanben

2007-05-01

In this paper, a novel method for the differentiation of the retinal pigment epithelium (RPE) cells after light-induced damage by two-photon excitation is presented. Fresh samples of RPE cells of pig eyes are obtained from local slaughterhouse. Light-induced damage is produced by the output from Ti: sapphire laser which is focused onto the RPE layer. We study the change of the autofluorescence properties of RPE after two-photon excitation with the same wavelength. Preliminary results show that after two-photon excitation, there are two clear changes in the emission spectrum. The first change is the blue-shift of the emission peak. The emission peak of the intact RPE is located at 592nm, and after excitation, it shifts to 540nm. It is supposed that the excitation has led to the increased autofluorescence of flavin whose emission peak is located at 540nm. The second change is the increased intensity of the emission peak, which might be caused by the accelerated aging because the autofluorescence of RPE would increase during aging process. Experimental results indicate that two-photon excitation could not only lead to the damage of the RPE cells in multiphoton RPE imaging, but also provide an evaluation of the light-induced damage.

Selective visualization of fluorescent sterols in Caenorhabditis elegans by bleach-rate-based image segmentation.

PubMed

Wüstner, Daniel; Landt Larsen, Ane; Faergeman, Nils J; Brewer, Jonathan R; Sage, Daniel

2010-04-01

The nematode Caenorhabditis elegans is a genetically tractable model organism to investigate sterol transport. In vivo imaging of the fluorescent sterol, dehydroergosterol (DHE), is challenged by C. elegans' high autofluorescence in the same spectral region as emission of DHE. We present a method to detect DHE selectively, based on its rapid bleaching kinetics compared to cellular autofluorescence. Worms were repeatedly imaged on an ultraviolet-sensitive wide field (UV-WF) microscope, and bleaching kinetics of DHE were fitted on a pixel-basis to mathematical models describing the intensity decay. Bleach-rate constants were determined for DHE in vivo and confirmed in model membranes. Using this method, we could detect enrichment of DHE in specific tissues like the nerve ring, the spermateca and oocytes. We confirm these results in C. elegans gut-granule-loss (glo) mutants with reduced autofluorescence and compare our method with three-photon excitation microscopy of sterol in selected tissues. Bleach-rate-based UV-WF imaging is a useful tool for genetic screening experiments on sterol transport, as exemplified by RNA interference against the rme-2 gene coding for the yolk receptor and for worm homologues of Niemann-Pick C disease proteins. Our approach is generally useful for identifying fluorescent probes in the presence of high cellular autofluorescence.

Fluorescence lifetime imaging ophthalmoscopy.

PubMed

Dysli, Chantal; Wolf, Sebastian; Berezin, Mikhail Y; Sauer, Lydia; Hammer, Martin; Zinkernagel, Martin S

2017-09-01

Imaging techniques based on retinal autofluorescence have found broad applications in ophthalmology because they are extremely sensitive and noninvasive. Conventional fundus autofluorescence imaging measures fluorescence intensity of endogenous retinal fluorophores. It mainly derives its signal from lipofuscin at the level of the retinal pigment epithelium. Fundus autofluorescence, however, can not only be characterized by the spatial distribution of the fluorescence intensity or emission spectrum, but also by a characteristic fluorescence lifetime function. The fluorescence lifetime is the average amount of time a fluorophore remains in the excited state following excitation. Fluorescence lifetime imaging ophthalmoscopy (FLIO) is an emerging imaging modality for in vivo measurement of lifetimes of endogenous retinal fluorophores. Recent reports in this field have contributed to our understanding of the pathophysiology of various macular and retinal diseases. Within this review, the basic concept of fluorescence lifetime imaging is provided. It includes technical background information and correlation with in vitro measurements of individual retinal metabolites. In a second part, clinical applications of fluorescence lifetime imaging and fluorescence lifetime features of selected retinal diseases such as Stargardt disease, age-related macular degeneration, choroideremia, central serous chorioretinopathy, macular holes, diabetic retinopathy, and retinal artery occlusion are discussed. Potential areas of use for fluorescence lifetime imaging ophthalmoscopy will be outlined at the end of this review. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Autofluorescence endoscopy with "real-time" digital image processing in differential diagnostics of selected benign and malignant lesions in the oesophagus.

PubMed

Sieroń-Stołtny, Karolina; Kwiatek, Sebastian; Latos, Wojciech; Kawczyk-Krupka, Aleksandra; Cieślar, Grzegorz; Stanek, Agata; Ziaja, Damian; Bugaj, Andrzej M; Sieroń, Aleksander

2012-03-01

Oesophageal papilloma and Barrett's oesophagus are benign lesions known as risk factors of carcinoma in the oesophagus. Therefore, it is important to diagnose these early changes before neoplastic transformation. Autofluorescence endoscopy is a fast and non-invasive method of imaging of tissues based on the natural fluorescence of endogenous fluorophores. The aim of this study was to prove the diagnostic utility of autofluorescence endoscopy with digital image processing in histological diagnosis of endoscopic findings in the upper digestive tract, primarily in the imaging of oesophageal papilloma. During the retrospective analysis of about 200 endoscopic procedures in the upper digestive tract, 67 cases of benign, precancerous or cancerous changes were found. White light endoscopy (WLE) image, single-channel (red or green) autofluorescence images, as well as green and red fluorescence intensities in two modal fluorescence image and red-to-green (R/G) ratio (Numerical Colour Value, NCV) were correlated with histopathologic results. The NCV analysis in autofluorescence imaging (AFI) showed increased R/G ratio in cancerous changes in 96% vs. 85% in WLE. Simultaneous analysis with digital image processing allowed us to diagnose suspicious tissue as cancerous in all of cases. Barrett's metaplasia was confirmed in 90% vs. 79% (AFI vs. WLE), and 98% in imaging with digital image processing. In benign lesions, WLE allowed us to exclude tissue as malignant in 85%. Using autofluorescence endoscopy R/G ratio was increased in only 10% of benign changes causing the picture to be interpreted as suspicious, but when both methods were used together, 97.5% were cases excluded as malignancies. Mean R/G ratios were estimated to be 2.5 in cancers, 1.25 in Barrett's metaplasia and 0.75 in benign changes and were statistically significant (p=0.04). Autofluorescence imaging is a sensitive method to diagnose precancerous and cancerous early stages of the diseases located in oesophagus. Especially in two-modal imaging including white light endoscopy, autofluorescence imaging with digital image processing seems to be a useful modality of early diagnostics. Also in observation of papilloma changes, it facilitates differentiation between neoplastic and benign lesions and more accurate estimation of the risk of potential malignancy. Copyright © 2011 Elsevier B.V. All rights reserved.

Development of a quantitative diagnostic method of estrogen receptor expression levels by immunohistochemistry using organic fluorescent material-assembled nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonda, Kohsuke, E-mail: gonda@med.tohoku.ac.jp; Miyashita, Minoru; Watanabe, Mika

2012-09-28

Highlights: Black-Right-Pointing-Pointer Organic fluorescent material-assembled nanoparticles for IHC were prepared. Black-Right-Pointing-Pointer New nanoparticle fluorescent intensity was 10.2-fold greater than Qdot655. Black-Right-Pointing-Pointer Nanoparticle staining analyzed a wide range of ER expression levels in tissue. Black-Right-Pointing-Pointer Nanoparticle staining enhanced the quantitative sensitivity for ER diagnosis. -- Abstract: The detection of estrogen receptors (ERs) by immunohistochemistry (IHC) using 3,3 Prime -diaminobenzidine (DAB) is slightly weak as a prognostic marker, but it is essential to the application of endocrine therapy, such as antiestrogen tamoxifen-based therapy. IHC using DAB is a poor quantitative method because horseradish peroxidase (HRP) activity depends on reaction time, temperature andmore » substrate concentration. However, IHC using fluorescent material provides an effective method to quantitatively use IHC because the signal intensity is proportional to the intensity of the photon excitation energy. However, the high level of autofluorescence has impeded the development of quantitative IHC using fluorescence. We developed organic fluorescent material (tetramethylrhodamine)-assembled nanoparticles for IHC. Tissue autofluorescence is comparable to the fluorescence intensity of quantum dots, which are the most representative fluorescent nanoparticles. The fluorescent intensity of our novel nanoparticles was 10.2-fold greater than quantum dots, and they did not bind non-specifically to breast cancer tissues due to the polyethylene glycol chain that coated their surfaces. Therefore, the fluorescent intensity of our nanoparticles significantly exceeded autofluorescence, which produced a significantly higher signal-to-noise ratio on IHC-imaged cancer tissues than previous methods. Moreover, immunostaining data from our nanoparticle fluorescent IHC and IHC with DAB were compared in the same region of adjacent tissues sections to quantitatively examine the two methods. The results demonstrated that our nanoparticle staining analyzed a wide range of ER expression levels with higher accuracy and quantitative sensitivity than DAB staining. This enhancement in the diagnostic accuracy and sensitivity for ERs using our immunostaining method will improve the prediction of responses to therapies that target ERs and progesterone receptors that are induced by a downstream ER signal.« less

Imaging of Neuronal Activity in Awake Mice by Measurements of Flavoprotein Autofluorescence Corrected for Cerebral Blood Flow.

PubMed

Takahashi, Manami; Urushihata, Takuya; Takuwa, Hiroyuki; Sakata, Kazumi; Takado, Yuhei; Shimizu, Eiji; Suhara, Tetsuya; Higuchi, Makoto; Ito, Hiroshi

2017-01-01

Green fluorescence imaging (e.g., flavoprotein autofluorescence imaging, FAI) can be used to measure neuronal activity and oxygen metabolism in living brains without expressing fluorescence proteins. It is useful for understanding the mechanism of various brain functions and their abnormalities in age-related brain diseases. However, hemoglobin in cerebral blood vessels absorbs green fluorescence, hampering accurate assessments of brain function in animal models with cerebral blood vessel dysfunctions and subsequent cerebral blood flow (CBF) alterations. In the present study, we developed a new method to correct FAI signals for hemoglobin-dependent green fluorescence reductions by simultaneous measurements of green fluorescence and intrinsic optical signals. Intrinsic optical imaging enabled evaluations of light absorption and scatters by hemoglobin, which could then be applied to corrections of green fluorescence intensities. Using this method, enhanced flavoprotein autofluorescence by sensory stimuli was successfully detected in the brains of awake mice, despite increases of CBF, and hemoglobin interference. Moreover, flavoprotein autofluorescence could be properly quantified in a resting state and during sensory stimulation by a CO 2 inhalation challenge, which modified vascular responses without overtly affecting neuronal activities. The flavoprotein autofluorescence signal data obtained here were in good agreement with the previous findings from a condition with drug-induced blockade of cerebral vasodilation, justifying the current assaying methodology. Application of this technology to studies on animal models of brain diseases with possible changes of CBF, including age-related neurological disorders, would provide better understanding of the mechanisms of neurovascular coupling in pathological circumstances.

Highly sensitive detection of human papillomavirus type 16 DNA using time-resolved fluorescence microscopy and long lifetime probes

NASA Astrophysics Data System (ADS)

Wang, Xue F.; Periasamy, Ammasi; Wodnicki, Pawel; Siadat-Pajouh, M.; Herman, Brian

1995-04-01

We have been interested in the role of Human Papillomavirus (HPV) in cervical cancer and its diagnosis; to that end we have been developing microscopic imaging and fluorescent in situ hybridization (FISH) techniques to genotype and quantitate the amount of HPV present at a single cell level in cervical PAP smears. However, we have found that low levels of HPV DNA are difficult to detect accurately because theoretically obtainable sensitivity is never achieved due to nonspecific autofluorescence, fixative induced fluorescence of cells and tissues, and autofluorescence of the optical components in the microscopic system. In addition, the absorption stains used for PAP smears are intensely autofluorescent. Autofluorescence is a rapidly decaying process with lifetimes in the range of 1-100 nsec, whereas phosphorescence and delayed fluorescence have lifetimes in the range of 1 microsecond(s) ec-10 msec. The ability to discriminate between specific fluorescence and autofluorescence in the time-domain has improved the sensitivity of diagnostic test such that they perform comparably to, or even more sensitive than radioisotopic assays. We have developed a novel time-resolved fluorescence microscope to improve the sensitivity of detection of specific molecules of interest in slide based specimens. This time-resolved fluorescence microscope is based on our recently developed fluorescence lifetime imaging microscopy (FILM) in conjunction with the use of long lifetime fluorescent labels. By using fluorescence in situ hybridization and the long lifetime probe (europium), we have demonstrated the utility of this technique for detection of HPV DNA in cervicovaginal cells. Our results indicate that the use of time-resolved fluorescence microscopy and long lifetime probes increases the sensitivity of detection by removing autofluorescence and will thus lead to improved early diagnosis of cervical cancer. Since the highly sensitive detection of DNA in clinical samples using fluorescence in situ hybridization image is useful for the diagnosis of many other type of diseases, the system we have developed should find numerous applications for the diagnosis of disease states.

Detection and characterization of stomach cancer and atrophic gastritis with fluorescence and Raman spectroscopy

NASA Astrophysics Data System (ADS)

Li, Xiaozhou; Lin, Junxiu; Jia, Chunde; Wang, Rong

2003-12-01

In this paper, we attempt to find a valid method to distinguish gastric cancer and atrophic gastritis. Auto-fluorescence and Raman spectroscopy of laser induced (514.5 nm and 488.0 nm) was measured. The serum spectrum is different between normal and cancer. Average value of diagnosis parameter for normal serum, red shift is less than 12 nm and Raman relative intensity of peak C by 514.5 nm excited is stronger than that of 488.0 nm. To gastric cancer, its red shift of average is bigger than 12 nm and relative intensity of Raman peak C by 514.5 nm excited is weaker than that by 488.0 nm. To atrophic gastritis, the distribution state of Raman peaks is similar with normal serum and auto-fluorescence spectrum's shape is similar to that of gastric cancer. Its average Raman peak red shift is bigger than 12 nm and the relative intensity of peak C by 514.5 excited is stronger than that of by 488.0. We considered it as a criterion and got an accuracy of 85.6% for diagnosis of gastric cancer compared with the result of clinical diagnosis.

Autofluorescences: Biological functions and technical applications

USDA-ARS?s Scientific Manuscript database

Fluorescence is the property by which a molecule (fluorophore), excited after the absorption of a photon, is able to de-excite by re-emitting a photon of a longer wavelength. Chlorophylls are the most remarkable examples of plant fluorophores, and their properties have been intensively studied as a ...

BSA Au clusters as a probe for enhanced fluorescence detection using multipulse excitation scheme.

PubMed

Raut, Sangram L; Rich, Ryan; Fudala, Rafal; Kokate, R; Kimball, J D; Borejdo, Julian; Vishwanatha, Jamboor K; Gryczynski, Zygmunt; Gryczynski, Ignacy

2014-01-01

Although BSA Au clusters fluoresce in red region (λmax: 650 nm), they are of limited use due to low fluorescence quantum yield (~6%). Here we report an enhanced fluorescence imaging application of fluorescent bio-nano probe BSA Au clusters using multipulse excitation scheme. Multipulse excitation takes advantage of long fluorescence lifetime (> 1 µs) of BSA Au clusters and enhances its fluorescence intensity 15 times over short lived cellular auto-fluorescence. Moreover we have also shown that by using time gated detection strategy signal (fluorescence of BSA Au clusters) to noise (auto-fluorescence) ratio can be increased by 30 fold. Thereby with multipulse excitation long lifetime probes can be used to develop biochemical assays and perform optical imaging with zero background.

Urinary NGAL in patients with and without acute kidney injury in a cardiology intensive care unit

PubMed Central

Watanabe, Mirian; Silva, Gabriela Fulan e; da Fonseca, Cassiane Dezoti; Vattimo, Maria de Fatima Fernandes

2014-01-01

Objective To assess the diagnostic and prognostic efficacy of urine neutrophil gelatinase-associated lipocalin in patients admitted to an intensive care unit. Methods Longitudinal, prospective cohort study conducted in a cardiology intensive care unit. The participants were divided into groups with and without acute kidney injury and were followed from admission to the intensive care unit until hospital discharge or death. Serum creatinine, urine output and urine neutrophil gelatinase-associated lipocalin were measured 24 and 48 hours after admission. Results A total of 83 patients admitted to the intensive care unit for clinical reasons were assessed, most being male (57.8%). The participants were divided into groups without acute kidney injury (N=18), with acute kidney injury (N=28) and with severe acute kidney injury (N=37). Chronic diseases, mechanical ventilation and renal replacement therapy were more common in the groups with acute kidney injury and severe acute kidney injury, and those groups exhibited longer intensive care unit stay and hospital stay and higher mortality. Serum creatinine did not change significantly in the group with acute kidney injury within the first 24 hours of admission to the intensive care unit, although, urine neutrophil gelatinase-associated lipocalin was high in the groups with acute kidney injury and severe acute kidney injury (p<0.001). Increased urine neutrophil gelatinase-associated lipocalin was associated with death. Conclusion An increase in urine neutrophil gelatinase-associated lipocalin precedes variations in serum creatinine in patients with acute kidney injury and may be associated with death. PMID:25607262

Skin autofluorescence and the association with renal and cardiovascular risk factors in chronic kidney disease stage 3.

PubMed

McIntyre, Natasha J; Fluck, Richard J; McIntyre, Christopher W; Taal, Maarten W

2011-10-01

Tissue advanced glycation end products (AGE) accumulation is a measure of cumulative metabolic stress. Assessment of tissue AGE by skin autofluorescence (SAF) correlates well with cardiovascular (CV) outcomes in diabetic, transplant, and dialysis patients, and may be a useful marker of CV risk in earlier stages of chronic kidney disease (CKD). 1707 patients with estimated GFR 59 to 30 ml/min per 1.73 m(2) were recruited from primary care practices for the Renal Risk In Derby (RRID) study. Detailed medical history was obtained, and each participant underwent clinical assessment as well as urine and serum biochemistry tests. SAF was assessed (mean of three readings) as a measure of skin AGE deposition using a cutaneous AF device (AGE Reader™, DiagnOptics, Groningen, The Netherlands). Univariate analysis revealed significant correlations between AF readings and several potential risk factors for cardiovascular disease (CVD) and progression of CKD. SAF readings (arbitrary units) were also significantly higher among males (2.8 ± 0.7 versus 2.7 ± 0.6), diabetics (3.0 ± 0.7 versus 2.7 ± 0.6), patients with evidence of self-reported CVD (2.9 ± 0.7 versus 2.7 ± 0.6), and those with no formal educational qualifications (2.8 ± 0.6 versus 2.6 ± 0.6; P < 0.01 for all). Multivariable linear regression analysis identified hemoglobin, diabetes, age, and eGFR as the most significant independent determinants of higher SAF (standardized coefficients -0.16, 0.13, 0.12, and -0.10, respectively; R(2) = 0.17 for equation). Increased SAF is independently associated with multiple CV and renal risk factors in CKD 3. Long-term follow-up will assess the value of SAF as a predictor of CV and renal risk in this population.

Potential applications of near infrared auto-fluorescence spectral polarized imaging for assessment of food quality

NASA Astrophysics Data System (ADS)

Zhou, Kenneth J.; Chen, Jun

2016-03-01

The current growing of food industry for low production costs and high efficiency needs for maintenance of high-quality standards and assurance of food safety while avoiding liability issues. Quality and safety of food depend on physical (texture, color, tenderness etc.), chemical (fat content, moisture, protein content, pH, etc.), and biological (total bacterial count etc.) features. There is a need for a rapid (less than a few minutes) and accurate detection system in order to optimize quality and assure safety of food. However, the fluorescence ranges for known fluorophores are limited to ultraviolet emission bands, which are not in the tissue near infrared (NIR) "optical window". Biological tissues excited by far-red or NIR light would exhibit strong emission in spectral range of 650-1,100 nm although no characteristic peaks show the emission from which known fluorophores. The characteristics of the auto-fluorescence emission of different types of tissues were found to be different between different tissue components such as fat, high quality muscle food. In this paper, NIR auto-fluorescence emission from different types of muscle food and fat was measured. The differences of fluorescence intensities of the different types of muscle food and fat emissions were observed. These can be explained by the change of the microscopic structure of physical, chemical, and biological features in meat. The difference of emission intensities of fat and lean meat tissues was applied to monitor food quality and safety using spectral polarized imaging, which can be detect deep depth fat under the muscle food up to several centimeter.

Fundus Autofluorescence and Photoreceptor Cell Rosettes in Mouse Models

PubMed Central

Flynn, Erin; Ueda, Keiko; Auran, Emily; Sullivan, Jack M.; Sparrow, Janet R.

2014-01-01

Purpose. This study was conducted to study correlations among fundus autofluorescence (AF), RPE lipofuscin accumulation, and photoreceptor cell degeneration and to investigate the structural basis of fundus AF spots. Methods. Fundus AF images (55° lens; 488-nm excitation) and spectral-domain optical coherence tomography (SD-OCT) scans were acquired in pigmented Rdh8−/−/Abca4−/− mice (ages 1–9 months) with a confocal scanning laser ophthalmoscope (cSLO). For quantitative fundus AF (qAF), gray levels (GLs) were calibrated to an internal fluorescence reference. Retinal bisretinoids were measured by quantitative HPLC. Histometric analysis of outer nuclear layer (ONL) thicknesses was performed, and cryostat sections of retina were examined by fluorescence microscopy. Results. Quantified A2E and qAF intensities increased until age 4 months in the Rdh8−/−/Abca4−/− mice. The A2E levels declined after 4 months of age, but qAF intensity values continued to rise. The decline in A2E levels in the Rdh8−/−/Abca4−/− mice paralleled reduced photoreceptor cell viability as reflected in ONL thinning. Hyperautofluorescent puncta in fundus AF images corresponded to photoreceptor cell rosettes in SD-OCT images and histological sections stained with hematoxylin and eosin. The inner segment/outer segment–containing core of the rosette emitted an autofluorescence detected by fluorescence microscopy. Conclusions. When neural retina is disordered, AF from photoreceptor cells can contribute to noninvasive fundus AF images. Hyperautofluorescent puncta in fundus AF images are attributable, in at least some cases, to photoreceptor cell rosettes. PMID:25015357

Fluorescence spectroscopy for neoplasms control

NASA Astrophysics Data System (ADS)

Bratchenko, I. A.; Kristoforova, Yu. A.; Myakinin, O. O.; Artemyev, D. N.; Kozlov, S. V.; Moryatov, A. A.; Zakharov, V. P.

2016-04-01

Investigation of malignant skin tumors diagnosis was performed involving two setups for native tissues fluorescence control in visible and near infrared regions. Combined fluorescence analysis for skin malignant melanomas and basal cell carcinomas was performed. Autofluorescence spectra of normal skin and oncological pathologies stimulated by 457 nm and 785 nm lasers were registered for 74 skin tissue samples. Spectra of 10 melanomas and 27 basal cell carcinomas were registered ex vivo. Skin tumors analysis was made on the basis of autofluorescence spectra intensity and curvature for analysis of porphyrins, lipo-pigments, flavins and melanin. Separation of melanomas and basal cell carcinomas was performed on the basis of discriminant analysis. Overall accuracy of basal cell carcinomas and malignant melanomas separation in current study reached 86.5% with 70% sensitivity and 92.6% specificity.

Correction of autofluorescence intensity for epithelial scattering by optical coherence tomography: a phantom study

NASA Astrophysics Data System (ADS)

Pahlevaninezhad, H.; Lee, A. M. D.; Hyun, C.; Lam, S.; MacAulay, C.; Lane, P. M.

2013-03-01

In this paper, we conduct a phantom study for modeling the autofluorescence (AF) properties of tissue. A combined optical coherence tomography (OCT) and AF imaging system is proposed to measure the strength of the AF signal in terms of the scattering layer thickness and concentration. The combined AF-OCT system is capable of estimating the AF loss due to scattering in the epithelium using the thickness and scattering concentration calculated from the co-registered OCT images. We define a correction factor to account for scattering losses in the epithelium and calculate a scatteringcorrected AF signal. We believe the scattering-corrected AF will reduce the diagnostic false-positives rate in the early detection of airway lesions due to confounding factors such as increased epithelial thickness and inflammations.

Cost-effective elimination of lipofuscin fluorescence from formalin-fixed brain tissue by white phosphor light emitting diode array.

PubMed

Sun, Yulong; Chakrabartty, Avi

2016-12-01

Autofluorescence of aldehyde-fixed tissues greatly hinders fluorescence microscopy. In particular, lipofuscin, an autofluorescent component of aged brain tissue, complicates fluorescence imaging of tissue in neurodegenerative diseases. Background and lipofuscin fluorescence can be reduced by greater than 90% through photobleaching using white phosphor light emitting diode arrays prior to treatment with fluorescent probes. We compared the effect of photobleaching versus established chemical quenchers on the quality of fluorescent staining in formalin-fixed brain tissue of frontotemporal dementia with tau-positive inclusions. Unlike chemical quenchers, which reduced fluorescent probe signals as well as background, photobleaching treatment had no effect on probe fluorescence intensity while it effectively reduced background and lipofuscin fluorescence. The advantages and versatility of photobleaching over established methods are discussed.

[Evaluation of fundus autofluorescence in hereditary retinal diseases using Heidelberg Retina Angiograph2].

PubMed

Côco, Monique; Baba, Natalia Tamie; Sallum, Juliana Maria Ferraz

2007-01-01

To define characteristics of the fundus autofluorescence examination, verifying usefulness in the diagnosis and care of hereditary retinal diseases. 28 patients, adults, divided equally into four groups with diagnoses of Stargardt macular dystrophy, cone dystrophy, retinitis pigmentosa and healthy volunteers for the establishment of the normality pattern. An average of nine images with the filter for fluorescein angiography was obtained for the formation of the image autofluorescence using Heidelberg Retina Angiograph2. The images of each group of patients were analyzed to verify common characteristics. The fundus autofluorescence of healthy volunteers showed the foveal area darker than the surrounding retina. The images of Stargardt macular dystrophy, in general, presented an oval central lesion, with reduced autofluorescence. The main alterations of the autofluorescence in patients with cone dystrophy were reduced foveal autofluorescence with a parafoveal ring of increased autofluorescence. In general, the images of retinitis pigmentosa showed outlying pigments with reduced autofluorescence, and of the foveal area, in some cases disorganization or reduced autofluorescence. The study showed the existence of patterns of fundus autofluorescence in the hereditary retinal diseases that allow the diagnosis and better interpretation of the pathogenesis of these diseases.

Issues in quantifying atrophic macular disease using retinal autofluorescence.

PubMed

Sunness, Janet S; Ziegler, Matthias D; Applegate, Carol A

2006-01-01

To demonstrate the potential and limits of autofluorescence imaging in identifying and delineating areas of atrophy. Fundus photographs and infrared scanning laser ophthalmoscope (SLO) imaging, SLO macular perimetry, and SLO autofluorescence imaging results were compared for two patients with geographic atrophy (GA) from age-related macular degeneration, one patient with pigmentary alteration of the retina, and two patients with Stargardt disease. The main outcome measure in this case series was the presence of reduced autofluorescence. Drusen may become undetectable during autofluorescence imaging for some patients, allowing simple identification of areas of GA with areas of reduced autofluorescence. In other patients, drusen themselves have decreased autofluorescence, despite having intact retinal function in the retina overlying them. Some patients may have areas of reduced autofluorescence that persist for many years, without evidence of the development of atrophy. In Stargardt disease, decreased autofluorescence can easily detect and delineate areas of scotoma. Areas with mottled autofluorescence may have overlying function, but the function may not be adequate to support a fixation locus in that area. Using decreased autofluorescence to delineate areas of atrophy may be helpful in atrophic macular disorders. For GA, correlation with fundus photographs or macular perimetry findings may be necessary to differentiate between drusen and atrophy. For Stargardt disease, the nature of areas of decreased autofluorescence may help explain visual function of those areas.

[Fundus autofluorescence in dry AMD - impact on disease progression].

PubMed

Vidinova, C N; Gouguchkova, P T; Vidinov, K N

2013-11-01

Fundus autofluorescence is a novel technique that gives us information about the RPE cells by evaluating the distribution of lipofuscin in the retina. The purpose of our study was to evaluate the diagnostic abilities of OCT, RTVue and fundus autofluorescence in predicting the progression of dry AMD. In our study 37 dry AMD patients were enrolled: 22 of them with druses and 15 with developed geographic atrophy. They all underwent complete ophthalmological examinations including OCT and autofluorescence. We used the RTVue OCT programmes HD line, Cross line, EMM5 and EMM5 progression in all cases. The autofluorescence was recorded with the help of the Canon CX1 fundus camera. OCT images in the AMD patients with dry AMD and large druses showed typical undulations in the RPE/choroid line and occasionally drusenoid detachment of the RPE. Autofluorescence showed different patterns. The confluent reticular autofluorescence was associated with the development of neovascular membranes. In geographic atrophy patient OCTs showed diminished retinal thickness measured with EMM5. On autofluorescence the findings at the border zone atrophic/normal retina were of particular importance. The diffuse increased autofluorescence in that area was considered to be a sign for further atrophy progression. Our results point out that OCT in combination with autofluorescence is important in following the progression of dry AMD. Pathological autofluorescence at the border of atrophic lesions is an important sign for disease activity. Although both OCT and autofluorescence visualise the changes in RPE, autofluorescence is of key importance in predicting the development of the disease. Georg Thieme Verlag KG Stuttgart · New York.

The Inherent Visible Light Signature of an Intense Underwater Ultraviolet Light Source Due to Combined Raman and Fluorescence Effects

DTIC Science & Technology

2000-01-01

Humans cannot see ultraviolet light. The blue-sensitive cones in the retina would respond weakly to ultraviolet wavelengths if exposed to them, but...545, 1992. 3. C. S. Yentsch, and D. A. Phinney, " Autofluorescence and Raman scattering in the marine underwater environment," Ocean Optics X, SPIE

Optical tomography of human skin with subcellular spatial and picosecond time resolution using intense near infrared femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Koenig, Karsten; Wollina, Uwe; Riemann, Iris; Peukert, Christiane; Halbhuber, Karl-Juergen; Konrad, Helga; Fischer, Peter; Fuenfstueck, Veronika; Fischer, Tobias W.; Elsner, Peter

2002-06-01

We describe the novel high resolution imaging tool DermaInspect 100 for non-invasive diagnosis of dermatological disorders based on multiphoton autofluorescence imaging (MAI)and second harmonic generation. Femtosecond laser pulses in the spectral range of 750 nm to 850 nm have been used to image in vitro and in vivo human skin with subcellular spatial and picosecond temporal resolution. The non-linear induced autofluorescence originates mainly from naturally endogenous fluorophores/protein structures like NAD(P)H, flavins, keratin, collagen, elastin, porphyrins and melanin. Second harmonic generation was observed in the stratum corneum and in the dermis. The system with a wavelength-tunable compact 80 MHz Ti:sapphire laser, a scan module with galvo scan mirrors, piezoelectric objective positioner, fast photon detector and time-resolved single photon counting unit was used to perform optical sectioning and 3D autofluorescence lifetime imaging (t-mapping). In addition, a modified femtosecond laser scanning microscope was involved in autofluorescence measurements. Tissues of patients with psoriasis, nevi, dermatitis, basalioma and melanoma have been investigated. Individual cells and skin structures could be clearly visualized. Intracellular components and connective tissue structures could be further characterized by tuning the excitation wavelength in the range of 750 nm to 850 nm and by calculation of mean fluorescence lifetimes per pixel and of particular regions of interest. The novel non-invasive imaging system provides 4D (x,y,z,t) optical biopsies with subcellular resolution and offers the possibility to introduce a further optical diagnostic method in dermatology.

Double-excitation fluorescence spectral imaging: eliminating tissue auto-fluorescence from in vivo PPIX measurements

NASA Astrophysics Data System (ADS)

Torosean, Sason; Flynn, Brendan; Samkoe, Kimberley S.; Davis, Scott C.; Gunn, Jason; Axelsson, Johan; Pogue, Brian W.

2012-02-01

An ultrasound coupled handheld-probe-based optical fluorescence molecular tomography (FMT) system has been in development for the purpose of quantifying the production of Protoporphyrin IX (PPIX) in aminolevulinic acid treated (ALA), Basal Cell Carcinoma (BCC) in vivo. The design couples fiber-based spectral sampling of PPIX fluorescence emission with a high frequency ultrasound imaging system, allowing regionally localized fluorescence intensities to be quantified [1]. The optical data are obtained by sequential excitation of the tissue with a 633nm laser, at four source locations and five parallel detections at each of the five interspersed detection locations. This method of acquisition permits fluorescence detection for both superficial and deep locations in ultrasound field. The optical boundary data, tissue layers segmented from ultrasound image and diffusion theory are used to estimate the fluorescence in tissue layers. To improve the recovery of the fluorescence signal of PPIX, eliminating tissue autofluorescence is of great importance. Here the approach was to utilize measurements which straddled the steep Qband excitation peak of PPIX, via the integration of an additional laser source, exciting at 637 nm; a wavelength with a 2 fold lower PPIX excitation value than 633nm.The auto-fluorescence spectrum acquired from the 637 nm laser is then used to spectrally decouple the fluorescence data and produce an accurate fluorescence emission signal, because the two wavelengths have very similar auto-fluorescence but substantially different PPIX excitation levels. The accuracy of this method, using a single source detector pair setup, is verified through animal tumor model experiments, and the result is compared to different methods of fluorescence signal recovery.

Immediate and long-term changes of fundus autofluorescence in continuous wave laser lesions of the retina.

PubMed

Framme, Carsten; Roider, Johann

2004-01-01

To determine whether fundus autofluorescence imaging is able to show changes in retinal pigment epithelium (RPE) fluorescence after thermal laser photocoagulation. In vivo imaging of fundus autofluorescence was performed with a scanning laser ophthalmoscope. A laser with a wavelength of 488 nm was used for excitation of the tissue and autofluorescence was detected above 500 nm using a barrier filter. One hundred eight eyes of 87 patients who had had previous laser treatment were monitored. The appearance and size of the laser lesions were documented and correlated to the time of treatment. Immediate changes were observed prospectively in 13 eyes; long-term follow-up was studied retrospectively in 95 eyes. In all patients but one, autofluorescence was decreased in the area of laser lesions 1 hour after laser treatment. After 1 month, previously decreased autofluorescence in all lesions changed to significantly increased autofluorescence, which was stable up to 6 months after treatment. Mixed forms were present approximately 6 to 12 months after treatment, showing a central island of increased autofluorescence surrounded by a ring of decreased autofluorescence. After 1 to 2 years, lesions again changed to complete dark spots, enlarging later on. RPE destruction and subsequent proliferation after continuous wave laser photocoagulation can be visualized noninvasively by autofluorescence imaging. Immediate decreased autofluorescence may indicate acute damage of the RPE, subsequent increased autofluorescence seems to indicate proliferative behavior of the RPE, and final dark spots can indicate RPE atrophy secondary to a denaturation of neurosensory retinal tissue. Thus, autofluorescence can be used in the long-term monitoring of RPE changes after laser treatment. The enlargement of the laser atrophy zone demonstrates the potential risk of visual loss after central laser photocoagulation even years after treatment.

[Fundus autofluorescence. Has it a place in the management of diabetic macular edema?

PubMed

Zbiba, W; Baba, A; Bouayed, E; Daldoul, A

2016-11-01

Analyze the characteristics of fundus autofluorescence of diabetic macular edema and study the association between these characteristics and visual function. Our study included 18 patients (28 eyes) with clinically significant diabetic macular edema. All patients had a complete eye examination with a fundus autofluorescence imaging and optical coherence tomography. The central macular thickness and central macular volume were measured. The integrity of the inner segment-outer segment junction and the integrity of the external limiting membrane were also evaluated in the same area. Among the 28 eyes studied, 8 had normal autofluorescence. The remaining 20 eyes had abnormal autofluorescence: a hyper-cystoid autofluorescence in 5 eyes (25%), hyper-spot autofluorescence in 8 eyes (40%), and hypo-irregular autofluorescence in 5 eyes (25%). Best corrected visual acuity was significantly better in patients with normal autofluorescence and those with hyper-cystoid autofluorescence. There was no significant difference in central macular thickness (P=0.186) and central macular volume (P=0.191) between the four groups. The autofluorescence is a simple, fast, and non-invasive technique for the study of diabetic macular edema with good correlation to the visual function as well as to the extent of damage to the retina. It is, therefore, a possible alternative to other invasive imaging techniques in particular in the long term monitoring of diabetic macular edema. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Microperimetric correlations of autofluorescence and optical coherence tomography imaging in dry age-related macular degeneration.

PubMed

Querques, Lea; Querques, Giuseppe; Forte, Raimondo; Souied, Eric H

2012-06-01

To investigate the microperimetric correlations of autofluorescence imaging and optical coherence tomography (OCT) in dry age-related macular degeneration (AMD). Retrospective, observational, cross-sectional study. Consecutive patients with dry AMD underwent a complete ophthalmologic examination, including best-corrected visual acuity (BCVA), blue fundus autofluorescence (FAF), near-infrared autofluorescence, and spectral-domain (SD)-OCT with integrated microperimetry. A total of 58 eyes of 29 patients (21 women; mean age 73 ± 9 years) were included. Mean BCVA was 0.28 ± 0.3 logarithm of the minimal angle of resolution (logMAR). Overall, 2842 points were analyzed as regards FAF and near-infrared autofluorescence patterns, the status of inner segment/outer segment (IS/OS) interface, and retinal sensitivity. We observed a good correlation between the FAF and near-infrared autofluorescence patterns for all the points graded (increased FAF/near-infrared autofluorescence, Pearson rho = 0.6, P = .02; decreased FAF/near-infrared autofluorescence, Pearson rho = 0.7, P = .01; normal FAF/near-infrared autofluorescence, Pearson rho = 0.7, P = .01). Mean retinal sensitivity was significantly reduced in cases of decreased FAF (4.73 ± 2.23 dB) or increased FAF (4.75 ± 2.39 dB) compared with normal FAF (7.44 ± 2.34 dB) (P = .001). Mean retinal sensitivity was significantly reduced in case of decreased near-infrared autofluorescence (3.87 ± 2.28 dB), compared with increased near-infrared autofluorescence (5.76 ± 2.44 dB) (P = .02); mean retinal sensitivity in case of increased near-infrared autofluorescence was significantly reduced compared with normal near-infrared autofluorescence (7.15 ± 2.38 dB) (P = .002). On SD-OCT, there was a high inverse correlation between retinal sensitivity and rate of disruptions in IS/OS interface (Pearson rho = -0.72, P = .001). A reduced retinal sensitivity consistently correlates with decreased FAF/near-infrared autofluorescence and a disrupted IS/OS interface. Increased near-infrared autofluorescence may represent a useful method for detection of retinal abnormalities early in dry AMD development. Copyright © 2012 Elsevier Inc. All rights reserved.

Comparison of Short-Wavelength Reduced-Illuminance and Conventional Autofluorescence Imaging in Stargardt Macular Dystrophy.

PubMed

Strauss, Rupert W; Muñoz, Beatriz; Jha, Anamika; Ho, Alexander; Cideciyan, Artur V; Kasilian, Melissa L; Wolfson, Yulia; Sadda, SriniVas; West, Sheila; Scholl, Hendrik P N; Michaelides, Michel

2016-08-01

To compare grading results between short-wavelength reduced-illuminance and conventional autofluorescence imaging in Stargardt macular dystrophy. Reliability study. setting: Moorfields Eye Hospital, London (United Kingdom). Eighteen patients (18 eyes) with Stargardt macular dystrophy. A series of 3 fundus autofluorescence images using 3 different acquisition parameters on a custom-patched device were obtained: (1) 25% laser power and total sensitivity 87; (2) 25% laser power and freely adjusted sensitivity; and (3) 100% laser power and freely adjusted total sensitivity (conventional). The total area of 2 hypoautofluorescent lesion types (definitely decreased autofluorescence and poorly demarcated questionably decreased autofluorescence) was measured. Agreement in grading between the 3 imaging methods was assessed by kappa coefficients (κ) and intraclass correlation coefficients. The mean ± standard deviation area for images acquired with 25% laser power and freely adjusted total sensitivity was 2.04 ± 1.87 mm(2) for definitely decreased autofluorescence (n = 15) and 1.86 ± 2.14 mm(2) for poorly demarcated questionably decreased autofluorescence (n = 12). The intraclass correlation coefficient (95% confidence interval) was 0.964 (0.929, 0.999) for definitely decreased autofluorescence and 0.268 (0.000, 0.730) for poorly demarcated questionably decreased autofluorescence. Short-wavelength reduced-illuminance and conventional fundus autofluorescence imaging showed good concordance in assessing areas of definitely decreased autofluorescence. However, there was significantly higher variability between imaging modalities for assessing areas of poorly demarcated questionably decreased autofluorescence. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Centrifugal expansion of fundus autofluorescence patterns in Stargardt disease over time.

PubMed

Cukras, Catherine A; Wong, Wai T; Caruso, Rafael; Cunningham, Denise; Zein, Wadih; Sieving, Paul A

2012-02-01

To study the longitudinal changes in autofluorescence in Stargardt disease to reveal aspects of disease progression not previously evident. Changes in autofluorescence reflect changing fluorophore compositions of lipofuscin and melanin in retinal pigment epithelial cells, which has been hypothesized to contribute to Stargardt disease pathogenesis. We examined the temporospatial patterns of fundus autofluorescence with excitation at both 488 nm (standard fundus autofluorescence) and 795 nm (near-infrared autofluorescence) in a longitudinal case series involving 8 eyes of 4 patients (range of follow-up, 11-57 months; mean, 39 months). Image processing was performed to analyze spatial and temporal cross-modality associations. Longitudinal fundus autofluorescence imaging of fleck lesions revealed hyperautofluorescent lesions that extended in a centrifugal direction from the fovea with time. Patterns of spread were nonrandom and followed a radial path that left behind a trail of diminishing autofluorescence. Longitudinal near-infrared autofluorescence imaging also demonstrated centrifugal lesion spread but with fewer hyperautofluorescent lesions, suggestive of more transient hyperautofluorescence and more rapid decay at longer wavelengths. Fundus autofluorescence and near-infrared autofluorescence abnormalities were spatially correlated with each other, and together they reflect systematic progressions in fleck distribution and fluorophore composition occurring during the natural history of the disease. Stargardt disease fleck lesions do not evolve randomly in location but instead follow consistent patterns of radial expansion and a systematic decay of autofluorescence that reflect changing lipofuscin and melanin compositions in retinal pigment epithelial cells. These progressive foveal-to-peripheral changes are helpful in elucidating molecular and cellular mechanisms underlying Stargardt disease and may constitute potential outcome measures in clinical trials.

Retinal flavoprotein autofluorescence as a measure of retinal health.

PubMed

Elner, Susan G; Elner, Victor M; Field, Matthew G; Park, Seung; Heckenlively, John R; Petty, Howard R

2008-01-01

To establish that increased autofluorescence of mitochondrial flavoproteins, an indicator of mitochondrial oxidative stress, correlates with retinal cell dysfunction. Retinal flavoprotein autofluorescence (FA) was imaged in humans with a fundus camera modified with 467DF8-nm excitation and 535-nm emission filters and a back-illuminated, electron-multiplying, charge-coupled device camera interfaced with a computer equipped with customized image capture software. Multiple digital images, centered on the fovea, were obtained from each eye. Histograms of pixel intensities in grayscale units were analyzed for average intensity and average curve width. Adults with diabetes mellitus, age-related macular degeneration (ARMD), central serous retinopathy, and retinal dystrophies, as well as healthy control volunteers, were imaged. Monolayers of cultured human retinal pigment epithelial (HRPE) cells, HRPE cells exposed to sublethal doses of H2O2, and HRPE cells exposed to H2O2 in the presence of antioxidants were imaged for FA using fluorescent photomicroscopy. Control patients demonstrated low levels of retinal FA, which increased progressively with age. Diabetics without visible retinopathy demonstrated increased FA levels compared to control volunteers (P < .001). Diabetics with retinopathy demonstrated significantly higher FA values than those without retinopathy (P < .04). Patients with ARMD, central serous retinopathy, or retinal dystrophies also demonstrated significantly increased FA. Compared to control RPE cells, cells oxidatively stressed with H2O2 had significantly elevated FA (P < .05), which was prevented by antioxidants (P < .05). Retinal FA is significantly increased with age and diseases known to be mediated by oxidative stress. Retinal FA imaging may provide a novel, noninvasive method of assessing retinal health and retinal dysfunction prior to retinal cell death.

Quantitative Autofluorescence Intensities in Acute Zonal Occult Outer Retinopathy vs Healthy Eyes

PubMed Central

Boudreault, Katherine; Schuerch, Kaspar; Zhao, Jin; Lee, Winston; Cabral, Thiago; Yannuzzi, Lawrence A.; Tsang, Stephen H.; Sparrow, Janet R.

2018-01-01

IMPORTANCE Acute zonal occult outer retinopathy (AZOOR) remains a challenging diagnosis. Early recognition of the disease depends on advances in imaging modalities that can improve phenotyping and contribute to the understanding of the underlying pathogenesis. OBJECTIVES To expand the range of approaches available to assist in the identification of AZOOR by multimodal imaging and to analyze the fundus lesions by quantifying short-wavelength fundus autofluorescence (quantitative fundus autofluorescence [qAF]) and spectral-domain optical coherence tomography. DESIGN, SETTING, AND PARTICIPANTS In this observational study, patients underwent imaging at Columbia University Medical Center between November 2010 and March 2016 and were analyzed between September 2015 and August 2016. Six patients diagnosed as having AZOOR were studied by qAF and spectral-domain optical coherence tomography and were compared with 30 age and race/ethnicity–matched controls from a database of 277 healthy control eyes. MAIN OUTCOMES AND MEASURES In unaffected regions of the macula, qAF was calculated within predetermined circularly arranged segments (qAF8). In addition, qAF was measured within specified regions of interest positioned at the autofluorescent lesion border (AZOOR line). Electroretinograms and electro-oculograms were recorded in 5 of 6 patients. RESULTS Among 6 patients (age range, 26–61 years; 4 female; 4 of white race/ethnicity, 1 Asian, and 1 Hispanic), 5 exhibited an autofluorescent AZOOR line in short-wavelength fundus autofluorescence images, delineating the peripapillary lesion. The mean (SD) region-of-interest qAF measured on the AZOOR line was 60 (26) times higher than in healthy control eyes (P = .03) at equivalent fundus locations. The qAF8 within nondiseased macular regions were within the normal range. At the lesion border, spectral-domain optical coherence tomography revealed a loss of outer retinal integrity in all patients. Single-flash cone b-wave latency and 30-Hz flicker latency responses were significantly delayed bilaterally. Lesions with smooth, homogeneous borders exhibited only minimal expansion in size over time, while the lesion in a patient with a heterogeneous border progressed more rapidly. CONCLUSIONS AND RELEVANCE The finding that qAF is elevated at the border between diseased and nondiseased retina in patients with AZOOR contributes to the understanding of the natural history of the disease. PMID:29075777

Fluorescence and fluorescence-lifetime imaging microscopy (FLIM) to characterize yeast strains by autofluorescence

NASA Astrophysics Data System (ADS)

Bhatta, H.; Goldys, E. M.; Ma, J.

2006-02-01

We characterised populations of wild type baking and brewing yeast cells using intrinsic fluorescence and fluorescence lifetime microscopy, in order to obtain quantitative identifiers of different strains. The cell autofluorescence was excited at 405 nm and observed within 440-540 nm range where strong cell to cell variability was observed. The images were analyzed using customised public domain software, which provided information on cell size, intensity and texture-related features. In light of significant diversity of the data, statistical methods were utilized to assess the validity of the proposed quantitative identifiers for strain differentiation. The Kolmogorov-Smirnov test was applied to confirm that empirical distribution functions for size, intensity and entropy for different strains were statistically different. These characteristics were followed with culture age of 24, 48 and 72 h, (the latter corresponding to a stationary growth phase) and size, and to some extent entropy, were found to be independent of age. The fluorescence intensity presented a distinctive evolution with age, different for each of the examined strains. The lifetime analysis revealed a short decay time component of 1.4 ns and a second, longer one with the average value of 3.5 ns and a broad distribution. High variability of lifetime values within cells was observed however a lifetime texture feature in the studied strains was statistically different.

Fluorescence lifetime imaging of skin cancer

NASA Astrophysics Data System (ADS)

Patalay, Rakesh; Talbot, Clifford; Munro, Ian; Breunig, Hans Georg; König, Karsten; Alexandrov, Yuri; Warren, Sean; Neil, Mark A. A.; French, Paul M. W.; Chu, Anthony; Stamp, Gordon W.; Dunsby, Chris

2011-03-01

Fluorescence intensity imaging and fluorescence lifetime imaging microscopy (FLIM) using two photon microscopy (TPM) have been used to study tissue autofluorescence in ex vivo skin cancer samples. A commercially available system (DermaInspect®) was modified to collect fluorescence intensity and lifetimes in two spectral channels using time correlated single photon counting and depth-resolved steady state measurements of the fluorescence emission spectrum. Uniquely, image segmentation has been used to allow fluorescence lifetimes to be calculated for each cell. An analysis of lifetime values obtained from a range of pigmented and non-pigmented lesions will be presented.

Label-free in vivo flow cytometry in zebrafish using two-photon autofluorescence imaging.

PubMed

Zeng, Yan; Xu, Jin; Li, Dong; Li, Li; Wen, Zilong; Qu, Jianan Y

2012-07-01

We demonstrate a label-free in vivo flow cytometry in zebrafish blood vessels based on two-photon excited autofluorescence imaging. The major discovery in this work is the strong autofluorescence emission from the plasma in zebrafish blood. The plasma autofluorescence provides excellent contrast for visualizing blood vessels and counting blood cells. In addition, the cellular nicotinamide adenine dinucleotide autofluorescence enables in vivo imaging and counting of white blood cells (neutrophils).

Contribution of glue layer into epidermis sample fluorescence dynamics

NASA Astrophysics Data System (ADS)

Salomatina, Elena V.; Chernova, Svetlana P.; Pravdin, Alexander B.

2000-04-01

In this work, the temporal behavior of autofluorescence of epidermis samples under UV-irradiation has ben studied. The samples were prepared using surface epidermis stripping technique. Fluorescence spectra and kinetic curves of fluorescence intensity have been obtained. It has been concluded that the glue composition used allows the measurement of epidermis fluorescence dynamics with the first 60 min of experiment.

Autofluorescence of choroidal nevus in 64 cases.

PubMed

Shields, Carol L; Pirondini, Cesare; Bianciotto, Carlos; Materin, Miguel A; Harmon, Sarah A; Shields, Jerry A

2008-10-01

To describe the autofluorescence features of choroidal nevi. Noncomparative case series. Sixty-four consecutive patients. Correlation of fundus photography with autofluorescence photography. Autofluorescence features of choroidal nevus and overlying retinal pigment epithelium (RPE). The mean patient age was 62 years. The choroidal nevus was a mean of 5 mm from the optic disk and foveola. The mean tumor basal dimension was 5.0 mm and mean tumor thickness was 1.0 mm. The choroidal nevus showed hypoautofluorescence in 56%, isoautofluorescence in 19%, and hyperautofluorescence in 25%. The autofluorescence features appeared unaffected by tumor thickness, but increasing tumor base and disrupted overlying RPE appeared to produce slightly brighter autofluorescence. Nevi located in the macular region showed darker hypoautofluorescence than those outside the macular region. Overlying RPE hyperplasia, atrophy, and fibrous metaplasia were generally hypoautofluorescent. Drusen, subretinal fluid, and orange pigment were generally hyperautofluorescent. The brightest hyperautofluorescence was found with orange pigment. Choroidal nevus shows little intrinsic autofluorescence. Overlying RPE alterations show dramatic autofluorescence ranging from dark hypoautofluorescence of RPE atrophy to bright hyperautofluorescence of orange pigment.

UV laser-induced fluorescence spectroscopy and laser Doppler flowmetry in the diagnostics of alopecia

NASA Astrophysics Data System (ADS)

Skomorokha, Diana P.; Pigoreva, Yulia N.; Salmin, Vladimir V.

2016-04-01

Development of optical biopsy methods has a great interest for medical diagnostics. In clinical and experimental studies it is very important to analyze blood circulation quickly and accurately, thereby laser Doppler flowmetry (LDF) is widely used. UV laser-induced fluorescence spectroscopy (UV LIFS) is express highly sensitive and widely-spread method with no destructive impact, high excitation selectivity and the possibility to use in highly scattering media. The goal of this work was to assess a correlation of UV laser-induced fluorescence spectroscopy and laser Doppler flowmetry parameters, and a possibility to identify or to differentiate various types of pathological changes in tissues according to their autofluorescence spectra. Three groups of patients with diffuse (symptomatic) alopecia, androgenic alopecia, and focal alopecia have been tested. Each groups consisted of not less than 20 persons. The measurements have been done in the parietal and occipital regions of the sculls. We used the original automated spectrofluorimeter to record autofluorescence spectra, and standard laser Doppler flowmeter BLF-21 (Transonic Systems, Inc., USA) to analyze the basal levels of blood circulation. Our results show that UV LIFS accurately distinguishes the zones with different types of alopecia. We found high correlation of the basal levels of blood circulation and the integrated intensity of autofluorescence in the affected tissue.

Quantitative method to assess caries via fluorescence imaging from the perspective of autofluorescence spectral analysis

NASA Astrophysics Data System (ADS)

Chen, Q. G.; Zhu, H. H.; Xu, Y.; Lin, B.; Chen, H.

2015-08-01

A quantitative method to discriminate caries lesions for a fluorescence imaging system is proposed in this paper. The autofluorescence spectral investigation of 39 teeth samples classified by the International Caries Detection and Assessment System levels was performed at 405 nm excitation. The major differences in the different caries lesions focused on the relative spectral intensity range of 565-750 nm. The spectral parameter, defined as the ratio of wavebands at 565-750 nm to the whole spectral range, was calculated. The image component ratio R/(G + B) of color components was statistically computed by considering the spectral parameters (e.g. autofluorescence, optical filter, and spectral sensitivity) in our fluorescence color imaging system. Results showed that the spectral parameter and image component ratio presented a linear relation. Therefore, the image component ratio was graded as <0.66, 0.66-1.06, 1.06-1.62, and >1.62 to quantitatively classify sound, early decay, established decay, and severe decay tissues, respectively. Finally, the fluorescence images of caries were experimentally obtained, and the corresponding image component ratio distribution was compared with the classification result. A method to determine the numerical grades of caries using a fluorescence imaging system was proposed. This method can be applied to similar imaging systems.

Fundus autofluorescence in serpiginouslike choroiditis.

PubMed

Gupta, Amod; Bansal, Reema; Gupta, Vishali; Sharma, Aman

2012-04-01

To report the fundus autofluorescence characteristics in serpiginouslike choroiditis. Twenty-nine patients with presumed tubercular serpiginouslike choroiditis between November 2008 and January 2010 underwent fundus autofluorescence imaging during the acute stage and at regular intervals till the lesions healed. All patients received antitubercular therapy with oral corticosteroids. The autofluorescence images were compared with color fundus photography and fundus fluorescein angiography. The main outcome measure was fundus autofluorescence characteristics of lesions during the course of the disease. The pattern of fundus autofluorescence changed as the lesions evolved from the acute to the healed stage. In acute stage, the lesions showed an ill-defined halo of increased autofluorescence (hyperautofluorescence), giving it a diffuse, amorphous appearance (Stage I, acute). As the lesions began to heal, a thin rim of decreased autofluorescence (hypoautofluorescence) surrounded the lesion, defining its edges. The lesions showed predominantly hyperautofluorescence with stippled pattern (Stage II, subacute). With further healing, the hypoautofluorescence progressed and the lesion appeared predominantly hypoautofluorescent with stippled pattern (Stage III, nearly resolved). On complete healing, the lesions became uniformly hypoautofluorescent (Stage IV, completely resolved). Fundus autofluorescence highlighted the areas of disease activity and was a quick imaging tool for monitoring the course of lesions in serpiginouslike choroiditis.

Fundus autofluorescence and optical coherence tomography of congenital grouped albinotic spots.

PubMed

Kim, David Y; Hwang, John C; Moore, Anthony T; Bird, Alan C; Tsang, Stephen H

2010-09-01

The purpose of this study was to describe the findings of fundus autofluores-cence (FAF) and optical coherence tomography in a series of patients with congenital grouped albinotic spots. Three eyes of three patients with congenital grouped albinotic spots were evaluated with FAF and optical coherence tomography imaging to evaluate the nature of the albinotic spots. In all three eyes with congenital grouped albinotic spots, FAF imaging showed autofluorescent spots corresponding to the albinotic spots seen on stereo biomicroscopy. One eye also had additional spots detected on FAF imaging that were not visible on stereo biomicroscopy or color fundus photographs. Fundus autofluorescence imaging of the spots showed decreased general autofluorescence and decreased peripheral autofluorescence surrounding central areas of retained or increased autofluorescence. Optical coherence tomography showed a disruption in signal from the hyperreflective layer corresponding to the inner and outer segment junction and increased signal backscattering from the choroid in the area of the spots. Fluorescein angiography showed early and stable hyperfluorescence of the spots without leakage. In this case series, FAF showed decreased autofluorescence of the spots consistent with focal retinal pigment epithelium atrophy or abnormal material blocking normal autofluorescence and areas of increased autofluorescence suggesting retinal pigment epithelium dysfunction. The findings of optical coherence tomography and fluorescein angiography suggest photoreceptor and retinal pigment epithelium layer abnormalities. Fundus autofluorescence and optical coherence tomography are useful noninvasive diagnostic adjuncts that can aid in the diagnosis of congenital grouped albinotic spots, help determine extent of disease, and contribute to our understanding of its pathophysiology.

Intraretinal Correlates of Reticular Pseudodrusen Revealed by Autofluorescence and En Face OCT.

PubMed

Paavo, Maarjaliis; Lee, Winston; Merriam, John; Bearelly, Srilaxmi; Tsang, Stephen; Chang, Stanley; Sparrow, Janet R

2017-09-01

We sought to determine whether information revealed from the reflectance, autofluorescence, and absorption properties of RPE cells situated posterior to reticular pseudodrusen (RPD) could provide insight into the origins and structure of RPD. RPD were studied qualitatively by near-infrared fundus autofluorescence (NIR-AF), short-wavelength fundus autofluorescence (SW-AF), and infrared reflectance (IR-R) images, and the presentation was compared to horizontal and en face spectral domain optical coherence tomographic (SD-OCT) images. Images were acquired from 23 patients (39 eyes) diagnosed with RPD (mean age 80.7 ± 7.1 [SD]; 16 female; 4 Hispanics, 19 non-Hispanic whites). In SW-AF, NIR-AF, and IR-R images, fundus RPD were recognized as interlacing networks of small scale variations in IR-R and fluorescence (SW-AF, NIR-AF) intensities. Darkened foci of RPD colocalized in SW-AF and NIR-AF images, and in SD-OCT images corresponded to disturbances of the interdigitation (IZ) and ellipsoid (EZ) zones and to more pronounced hyperreflective lesions traversing photoreceptor-attributable bands in SD-OCT images. Qualitative assessment of the outer nuclear layer (ONL) revealed thinning as RPD extended radially from the outer to inner retina. In en face OCT, hyperreflective areas in the EZ band correlated topographically with hyporeflective foci at the level of the RPE. The hyperreflective lesions corresponding to RPD in SD-OCT scans are likely indicative of degenerating photoreceptor cells. The darkened foci at positions of RPD in NIR-AF and en face OCT images indicate changes in the RPE monolayer with the reduced NIR-AF and en face OCT signal suggesting a reduction in melanin that could be accounted for by RPE thinning.

Development of excitation light source for photodynamic diagnosis

NASA Astrophysics Data System (ADS)

Lim, Hyun Soo

2008-02-01

Photodynamic diagnosis (PDD) is a method to diagnose the possibility of cancer, both by the principle that if a photosensitizer is injected into an organic tissue, it is accumulated in the tissue of a malignant tumor selectively after a specific period, and by a comparison of the intensity of the fluorescence of normal tissue with abnormal tissue after investigating the excitation light of a tissue with accumulated photosensitizer. Currently, there are two methods of PDD: The first is a way to acquire incitement fluorescence by using a photosensitizer, and the second is a way to use auto-fluorescence by green fluorescence protein (GFP) and red fluorescence protein (RFP) such as NADH+ active factors within the organic body. Since the selection of the wavelength band of excitation light has an interrelation with fluorescence generation according to the selection of a photosensitizer, it plays an important role in PDD. This study aims at designing and evaluating light source devices that can stably generate light with various kinds of wavelengths in order to make possible PDD using a photosensitizer and diagnosis using auto-fluorescence. The light source was a Xenon lamp and filter wheel, composed of an optical output control through Iris and filters with several wavelength bands. It also makes the inducement of auto-fluorescence possible because it is designed to generate a wavelength band of 380-420nm, 430-480nm, 480-560nm. The transmission part of the light source was developed to enhance the efficiency of light transmission. To evaluate this light source, the characteristics of light output and wavelength band were verified. To validate the capability of this device as PDD, the detection of auto-fluorescence using mouse models was performed.

Near-infrared autofluorescence imaging to detect parathyroid glands in thyroid surgery.

PubMed

Ladurner, R; Al Arabi, N; Guendogar, U; Hallfeldt, Kkj; Stepp, H; Gallwas, Jks

2018-01-01

Objective To identify and save parathyroid glands during thyroidectomy by displaying their autofluorescence. Methods Autofluorescence imaging was carried out during thyroidectomy with and without central lymph node dissection. After visual recognition by the surgeon, the parathyroid glands and the surrounding tissue were exposed to near-infrared light with a wavelength of 690-770 nm using a modified Karl Storz near infrared/indocyanine green endoscopic system. Parathyroid tissue was expected to show near infrared autofluorescence at 820 nm, captured in the blue channel of the camera. Results We investigated 41 parathyroid glands from 20 patients; 37 glands were identified correctly based on near-infrared autofluorescence. Neither lymph nodes nor thyroid revealed substantial autofluorescence and nor did adipose tissue. Conclusions Parathyroid tissue is characterised by showing autofluorescence in the near-infrared spectrum. This effect can be used to identify and preserve parathyroid glands during thyroidectomy.

Analysis of spectrally resolved autofluorescence images by support vector machines

NASA Astrophysics Data System (ADS)

Mateasik, A.; Chorvat, D.; Chorvatova, A.

2013-02-01

Spectral analysis of the autofluorescence images of isolated cardiac cells was performed to evaluate and to classify the metabolic state of the cells in respect to the responses to metabolic modulators. The classification was done using machine learning approach based on support vector machine with the set of the automatically calculated features from recorded spectral profile of spectral autofluorescence images. This classification method was compared with the classical approach where the individual spectral components contributing to cell autofluorescence were estimated by spectral analysis, namely by blind source separation using non-negative matrix factorization. Comparison of both methods showed that machine learning can effectively classify the spectrally resolved autofluorescence images without the need of detailed knowledge about the sources of autofluorescence and their spectral properties.

The reduction of retinal autofluorescence caused by light exposure.

PubMed

Morgan, Jessica I W; Hunter, Jennifer J; Merigan, William H; Williams, David R

2009-12-01

A prior study showed that long exposure to 568-nm light at levels below the maximum permissible exposure safety limit produces retinal damage preceded by a transient reduction in the autofluorescence of retinal pigment epithelial (RPE) cells in vivo. The present study shows how the effects of exposure power and duration combine to produce this autofluorescence reduction and find the minimum exposure causing a detectable autofluorescence reduction. Macaque retinas were imaged using a fluorescence adaptive optics scanning laser ophthalmoscope to resolve individual RPE cells in vivo. The retina was exposed to 568-nm light over a square subtending 0.5 degrees with energies ranging from 1 to 788 J/cm(2), where power and duration were independently varied. In vivo exposures of 5 J/cm(2) and higher caused an immediate decrease in autofluorescence followed by either full autofluorescence recovery (exposures or= 247 J/cm(2)). No significant autofluorescence reduction was observed for exposures of 2 J/cm(2) and lower. Reciprocity of exposure power and duration held for the exposures tested, implying that the total energy delivered to the retina, rather than its distribution in time, determines the amount of autofluorescence reduction. That reciprocity held is consistent with a photochemical origin, which may or may not cause retinal degeneration. The implementation of safe methods for delivering light to the retina requires a better understanding of the mechanism causing autofluorescence reduction. Finally, RPE imaging was demonstrated using light levels that do not cause a detectable reduction in autofluorescence.

The Reduction of Retinal Autofluorescence Caused by Light Exposure

PubMed Central

Morgan, Jessica I. W.; Hunter, Jennifer J.; Merigan, William H.; Williams, David R.

2009-01-01

Purpose We have previously shown that long exposure to 568 nm light at levels below the maximum permissible exposure safety limit produces retinal damage preceded by a transient reduction in the autofluorescence of retinal pigment epithelial (RPE) cells in vivo. Here, we determine how the effects of exposure power and duration combine to produce this autofluorescence reduction and find the minimum exposure causing a detectable autofluorescence reduction. Methods Macaque retinas were imaged using a fluorescence adaptive optics scanning laser ophthalmoscope to resolve individual RPE cells in vivo. The retina was exposed to 568 nm light over a square subtending 0.5° with energies ranging from 1 J/cm2 to 788 J/cm2, where power and duration were independently varied. Results In vivo exposures of 5 J/cm2 and higher caused an immediate decrease in autofluorescence followed by either full autofluorescence recovery (exposures ≤ 210 J/cm2) or permanent RPE cell damage (exposures ≥ 247 J/cm2). No significant autofluorescence reduction was observed for exposures of 2 J/cm2 and lower. Reciprocity of exposure power and duration held for the exposures tested, implying that the total energy delivered to the retina, rather than its distribution in time, determines the amount of autofluorescence reduction. Conclusions That reciprocity holds is consistent with a photochemical origin, which may or may not cause retinal degeneration. The implementation of safe methods for delivering light to the retina requires a better understanding of the mechanism causing autofluorescence reduction. Finally, RPE imaging was demonstrated using light levels that do not cause a detectable reduction in autofluorescence. PMID:19628734

Skin autofluorescence predicts cardiovascular mortality in patients on chronic hemodialysis.

PubMed

Kimura, Hiroshi; Tanaka, Kenichi; Kanno, Makoto; Watanabe, Kimio; Hayashi, Yoshimitsu; Asahi, Koichi; Suzuki, Hodaka; Sato, Keiji; Sakaue, Michiaki; Terawaki, Hiroyuki; Nakayama, Masaaki; Miyata, Toshio; Watanabe, Tsuyoshi

2014-10-01

Tissue accumulation of advanced glycation end products (AGE) is thought to contribute to the progression of cardiovascular disease (CVD). Skin autofluorescence, a non-invasive measure of AGE accumulation using autofluorescence of the skin under ultraviolet light, has been reported to be an independent predictor of mortality associated with CVD in Caucasian patients on chronic hemodialysis. The aim of this study was to assess the predictive value of skin autofluorescence on all-cause and cardiovascular mortality in non-Caucasian (Japanese) patients on chronic hemodialysis. Baseline skin autofluorescence was measured with an autofluorescence reader in 128 non-Caucasian (Japanese) patients on chronic hemodialysis. All-cause and cardiovascular mortality was monitored prospectively during a period of 6 years. During the follow-up period, 42 of the 128 patients died; 19 of those patients died of CVD. Skin autofluorescence did not have a significant effect on all-cause mortality. However, age, carotid artery intima-media thickness (IMT), serum albumin, high-sensitivity C-reactive protein (hsCRP), skin autofluorescence and pre-existing CVD were significantly correlated with cardiovascular mortality. Multivariate Cox regression analysis showed skin autofluorescence (adjusted hazard ratio [HR] 3.97; 95% confidence interval [CI]1.67-9.43), serum albumin (adjusted HR 0.05; 95% CI 0.01-0.32), and hsCRP (adjusted HR 1.55; 95% CI 1.18-2.05) to be independent predictors of cardiovascular mortality. The present study suggests that skin autofluorescence is an independent predictor of cardiovascular mortality in non-Caucasian (Japanese) patients on chronic hemodialysis. © 2014 The Authors. Therapeutic Apheresis and Dialysis © 2014 International Society for Apheresis.

Autofluorescence detection of arbuscular mycorrhizal fungal structures in palm roots: an underestimated experimental method.

PubMed

Dreyer, Beatriz; Morte, Asunción; Pérez-Gilabert, Manuela; Honrubia, Mario

2006-08-01

The aim of this study was to reassess the use of autofluorescence for evaluating AM colonization in mycorrhizal roots in the light of criticisms of this method that affirmed that only metabolically inactive arbuscules autofluoresce. It was also investigated whether other mycorrhizal structures, such as hyphae, vesicles and spores, could be detected by autofluorescence, and whether the autofluorescence pattern of AM fungal structures could be exploited methodologically, for example, in the detection and sorting of spores by flow cytometry. Mycorrhizal roots of the palm species Brahea armata, Chamaerops humilis, Phoenix canariensis and Phoenix dactylifera were sectioned and observed by means of fluorescence microscopy. In addition, fungal structures isolated from mycorrhizal roots of P. dactylifera were examined. The same root sections and isolated fungal structures were subjected to vital staining with nitro blue tetrazolium to determine their metabolic state (active or inactive). Moreover, spores of Glomus intraradices, and Glomus clarum were studied by epifluorescence and flow cytometry. Mycorrhizal whole roots of Medicago sativa were also assessed by autofluorescence detection. In contrast to previous reports, the results presented in this paper clearly demonstrate that all fungal structures, both intra- and extraradical, autofluoresced under blue light excitation, regardless of their state (dead or alive). Some arbuscules isolated from roots and mature spores showed further autofluorescence under green light excitation. The source of the autofluorescence was localized in the fungal cell wall. It was shown that AM spores can be detected by flow cytometry. The results support the use of autofluorescence for the evaluation of AM colonization, at least in palm species, and refute previous criticisms of the method.

Fundus autofluorescence: applications and perspectives.

PubMed

Cuba, J; Gómez-Ulla, F

2013-02-01

To describe the findings of the study of autofluorescence of the different retinal diseases included in the study. To determine in which diseases autofluorescence may be more, or just as, useful as fluorescein angiography (FAG) in terms of diagnostic information. We studied the retinal autofluorescence of 123 eyes of 93 patients, including various diseases of the eye fundus. In all cases we explored the fundus, retinal autofluorescence, and, if indicated, FAG was performed. Analysis of the autofluorescence was performed using the Heidelberg Retina angiography Angiograph 2 (HRA2) Heidelberg Engineering (Germany). The autofluorescence information provided was equal or better (than FAG) in: 68.18% of cases of macular edema, 50% of pigment epithelium detachments, 100% of pigment epithelium atrophies, 100% of central serous chorioretinopathy; 55.55% of choroidal neovascularization, 100% of retinal dystrophies with deposition of lipofuscin, 100% of hard exudates and pre-retinal hemorrhages. Autofluorescence is a quick and non-invasive examination method, comfortable for both patient and examiner, and with a very short learning curve. It provides diagnostic information about many eye fundus diseases. While more studies and more experience with its use are needed, its interest lies in the possibility of avoiding the performing of angiography in patients with these diseases, and in the additional information autofluorescence provides about the functional situation of cells and retinal pigments. Copyright © 2011 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

Fundus Autofluorescence and Optical Coherence Tomography of Congenital Grouped Albinotic Spots

PubMed Central

Kim, David Y.; Hwang, John C.; Moore, Anthony T.; Bird, Alan C.; Tsang, Stephen H.

2010-01-01

Purpose To describe fundus autofluorescence (FAF) and optical coherence tomography (OCT) in a series of patients with congenital grouped albinotic spots (CGAS). Methods Three eyes of three patients with CGAS were evaluated with FAF and OCT imaging to evaluate the nature of the albinotic spots. Results In all three eyes with CGAS, FAF imaging revealed autofluorescent spots corresponding to the albinotic spots seen on stereo biomicroscopy. One eye also had additional spots detected on FAF imaging that were not visible on stereo biomicroscopy or color fundus photographs. FAF imaging of the spots demonstrated decreased general autofluorescence as well as decreased peripheral autofluorescence surrounding central areas of retained or increased autofluorescence. OCT revealed a disruption in signal from the hyper-reflective layer corresponding to the photoreceptor inner and outer segment junction as well as increased signal backscattering from the choroid in the area of the spots. Fluorescein angiography (FA) demonstrated early and stable hyperfluorescence of the spots without leakage. Conclusion In this case series, FAF demonstrated decreased autofluorescence of the spots consistent with focal RPE atrophy or abnormal material blocking normal autofluorescence as well as areas of increased autofluorescence suggesting RPE dysfunction. OCT and FA findings suggest photoreceptor and RPE layer abnormalities. FAF and OCT are useful noninvasive diagnostic adjuncts that can aid in the diagnosis of GCAS, help determine extent of disease, and contribute to our understanding of its pathophysiology. PMID:20539258

Skin Autofluorescence and the Association with Renal and Cardiovascular Risk Factors in Chronic Kidney Disease Stage 3

PubMed Central

McIntyre, Natasha J.; Fluck, Richard J.; McIntyre, Christopher W.

2011-01-01

Summary Background and objectives Tissue advanced glycation end products (AGE) accumulation is a measure of cumulative metabolic stress. Assessment of tissue AGE by skin autofluorescence (SAF) correlates well with cardiovascular (CV) outcomes in diabetic, transplant, and dialysis patients, and may be a useful marker of CV risk in earlier stages of chronic kidney disease (CKD). Design, setting, participants, & measurements 1707 patients with estimated GFR 59 to 30ml/min per 1.73 m2 were recruited from primary care practices for the Renal Risk In Derby (RRID) study. Detailed medical history was obtained, and each participant underwent clinical assessment as well as urine and serum biochemistry tests. SAF was assessed (mean of three readings) as a measure of skin AGE deposition using a cutaneous AF device (AGE Reader™, DiagnOptics, Groningen, The Netherlands). Results Univariate analysis revealed significant correlations between AF readings and several potential risk factors for cardiovascular disease (CVD) and progression of CKD. SAF readings (arbitrary units) were also significantly higher among males (2.8 ± 0.7 versus 2.7 ± 0.6), diabetics (3.0 ± 0.7 versus 2.7 ± 0.6), patients with evidence of self-reported CVD (2.9 ± 0.7 versus 2.7 ± 0.6), and those with no formal educational qualifications (2.8 ± 0.6 versus 2.6 ± 0.6; P < 0.01 for all). Multivariable linear regression analysis identified hemoglobin, diabetes, age, and eGFR as the most significant independent determinants of higher SAF (standardized coefficients −0.16, 0.13, 0.12, and −0.10, respectively; R2 = 0.17 for equation). Conclusion Increased SAF is independently associated with multiple CV and renal risk factors in CKD 3. Long-term follow-up will assess the value of SAF as a predictor of CV and renal risk in this population. PMID:21885790

Two-photon excited autofluorescence imaging of freshly isolated frog retinas.

PubMed

Lu, Rong-Wen; Li, Yi-Chao; Ye, Tong; Strang, Christianne; Keyser, Kent; Curcio, Christine A; Yao, Xin-Cheng

2011-06-01

The purpose of this study was to investigate cellular sources of autofluorescence signals in freshly isolated frog (Rana pipiens) retinas. Equipped with an ultrafast laser, a laser scanning two-photon excitation fluorescence microscope was employed for sub-cellular resolution examination of both sliced and flat-mounted retinas. Two-photon imaging of retinal slices revealed autofluorescence signals over multiple functional layers, including the photoreceptor layer (PRL), outer nuclear layer (ONL), outer plexiform layer (OPL), inner nuclear layer (INL), inner plexiform layer (IPL), and ganglion cell layer (GCL). Using flat-mounted retinas, depth-resolved imaging of individual retinal layers further confirmed multiple sources of autofluorescence signals. Cellular structures were clearly observed at the PRL, ONL, INL, and GCL. At the PRL, the autofluorescence was dominantly recorded from the intracellular compartment of the photoreceptors; while mixed intracellular and extracellular autofluorescence signals were observed at the ONL, INL, and GCL. High resolution autofluorescence imaging clearly revealed mosaic organization of rod and cone photoreceptors; and sub-cellular bright autofluorescence spots, which might relate to connecting cilium, was observed in the cone photoreceptors only. Moreover, single-cone and double-cone outer segments could be directly differentiated.

Intraoperative near-infrared autofluorescence imaging of parathyroid glands.

PubMed

Ladurner, Roland; Sommerey, Sandra; Arabi, Nora Al; Hallfeldt, Klaus K J; Stepp, Herbert; Gallwas, Julia K S

2017-08-01

To identify parathyroid glands intraoperatively by exposing their autofluorescence using near-infrared light. Fluorescence imaging was carried out during minimally invasive and open parathyroid and thyroid surgery. After identification, the parathyroid glands as well as the surrounding tissue were exposed to near-infrared (NIR) light with a wavelength of 690-770 nm using a modified Karl Storz near-infrared/indocyanine green (NIR/ICG) endoscopic system. Parathyroid tissue was expected to show near-infrared autofluorescence, captured in the blue channel of the camera. Whenever possible the visual identification of parathyroid tissue was confirmed histologically. In preliminary investigations, using the original NIR/ICG endoscopic system we noticed considerable interference of light in the blue channel overlying the autofluorescence. Therefore, we modified the light source by interposing additional filters. In a second series, we investigated 35 parathyroid glands from 25 patients. Twenty-seven glands were identified correctly based on NIR autofluorescence. Regarding the extent of autofluorescence, there were no noticeable differences between parathyroid adenomas, hyperplasia and normal parathyroid glands. In contrast, thyroid tissue, lymph nodes and adipose tissue revealed no substantial autofluorescence. Parathyroid tissue is characterized by showing autofluorescence in the near-infrared spectrum. This effect can be used to distinguish parathyroid glands from other cervical tissue entities.

Summary of studies on the blue-green autofluorescence and light transmission of the ocular lens

NASA Astrophysics Data System (ADS)

Van Best, Jaap A.; Kuppens, Esmeralda V.

1996-07-01

This paper reviews previous work done to demonstrate the clinical relevance of the measurement of blue-green autofluorescence and light transmission of the ocular lens. These can be determined quantitatively with fluorophotometry in a few seconds. Autofluorescence and transmission values are determined in healthy volunteers, in patients with insulin-dependent diabetes mellitus, and in patients with untreated glaucoma or untreated ocular hypertension. The lens autofluorescence of healthy volunteers increased linearly and transmission decreased exponentially with age. Each year of diabetes induced an increase of autofluorescence equal to one extra year of age. Untreated glaucoma or ocular hypertension had no significant effect on lens autofluorescence and transmission. Increased autofluorescence and decreased transmission values in comparison with values of a healthy population are proved to be indicative for an increased risk of developing cataract and the clinical usefulness of these measures is demonstrated. Diabetes is a risk factor for developing cataracts while untreated glaucoma or ocular hypertension is not.

Characterization of porcine eyes based on autofluorescence lifetime imaging

NASA Astrophysics Data System (ADS)

Batista, Ana; Breunig, Hans Georg; Uchugonova, Aisada; Morgado, António Miguel; König, Karsten

2015-03-01

Multiphoton microscopy is a non-invasive imaging technique with ideal characteristics for biological applications. In this study, we propose to characterize three major structures of the porcine eye, the cornea, crystalline lens, and retina using two-photon excitation fluorescence lifetime imaging microscopy (2PE-FLIM). Samples were imaged using a laser-scanning microscope, consisting of a broadband sub-15 femtosecond (fs) near-infrared laser. Signal detection was performed using a 16-channel photomultiplier tube (PMT) detector (PML-16PMT). Therefore, spectral analysis of the fluorescence lifetime data was possible. To ensure a correct spectral analysis of the autofluorescence lifetime data, the spectra of the individual endogenous fluorophores were acquired with the 16-channel PMT and with a spectrometer. All experiments were performed within 12h of the porcine eye enucleation. We were able to image the cornea, crystalline lens, and retina at multiple depths. Discrimination of each structure based on their autofluorescence intensity and lifetimes was possible. Furthermore, discrimination between different layers of the same structure was also possible. To the best of our knowledge, this was the first time that 2PE-FLIM was used for porcine lens imaging and layer discrimination. With this study we further demonstrated the feasibility of 2PE-FLIM to image and differentiate three of the main components of the eye and its potential as an ophthalmologic technique.

Tissue characterization by time-resolved fluorescence spectroscopy of endogenous and exogenous fluorochromes: apparatus design and preliminary results

NASA Astrophysics Data System (ADS)

Glanzmann, Thomas M.; Ballini, Jean-Pierre; Jichlinski, Patrice; van den Bergh, Hubert; Wagnieres, Georges A.

1996-12-01

The biomedical use of an optical fiber-based spectro- temporal fluorometer that can endoscopically record the fluorescence decay of an entire spectrum without scanning is presented. The detector consists of a streak camera coupled to a spectrograph. A mode-locked argon ion pumped dye laser or a nitrogen laser-pumped dye laser are used as pulsed excitation light sources. We measured the fluorescence decays of endogenous fluorophores and of ALA-induced- protoporphyrin IX(PPIX) in an excised human bladder with a carcinoma in situ (CIS). Each autofluorescence decay can be decomposed in at least three exponential components for all tissue samples investigated if the excitation is at 425 nm. The decays of the autofluorescence of all normal sites of the human bladder are similar and they differ significantly from the decays measured on the CIS and the necrotic tissue. The fluorescence of the ALA-induced PPIX in the bladder is monoexponential with a lifetime of 15 (plus or minus 1) ns and this fluorescence lifetime does not change significantly between the normal urothelium and the CIS. A photoproduct of ALA-PPIX with a fluorescence maximum at 670 nm and a lifetime of 8 (plus or minus 1) ns was observed. The measurement of the decay of the autofluorescence allowed to correctly identify a normal tissue site that was classified as abnormal by the measurement of the ALA-PPIX fluorescence intensity.

Real-time confocal laser endomicroscopic evaluation of primary liver cancer based on human liver autofluorescence.

PubMed

Maki, Harufumi; Kawaguchi, Yoshikuni; Arita, Junichi; Akamatsu, Nobuhisa; Kaneko, Junichi; Sakamoto, Yoshihiro; Hasegawa, Kiyoshi; Harihara, Yasushi; Kokudo, Norihiro

2017-02-01

Confocal laser endomicroscopy (CLE) is available for real-time microscopic examination. This study aims to evaluate the usefulness of intraoperative CLE examination as a modality to evaluate surgical margins in surgery for primary liver cancer. A probe-based CLE system (Cellvizio 100, Mauna Kea Technologies, Paris, France) was used. The subjects comprised seven specimens obtained from six patients with primary liver cancer in November 2015. The probe was manually attached to the surfaces of specimens, and images were collected without external fluorophores. CLE images were compared with hematoxylin and eosin-stained slides. Fluorescence intensity (FI) values of the CLE images were assessed using luminance-analyzing software. CLE examination visualized non-cancerous regions in the background liver as regular structures with high fluorescence because of human liver autofluorescence. Conversely, hepatocellular carcinoma and intrahepatic cholangiocarcinoma were depicted as irregular structures with low fluorescence. The median FI values of the non-cancerous regions and the cancerous regions were 104 (79.8-156) and 74.9 (60.6-106), respectively, and were significantly different (P = 0.031). The probe-based CLE enables real-time differentiation of cancerous regions from non-cancerous tissues in surgical specimens because of human liver autofluorescence. CLE can be used to confirm negative surgical margins in the operating room. J. Surg. Oncol. 2017;115:151-157. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Human Peripheral Blood Mononuclear Cells Cultured in Normal and Hyperglycemic Media in Simulated Microgravity Using NASA Bioreactors

NASA Technical Reports Server (NTRS)

Lawless, DeSales

2003-01-01

We sought answers to several questions this summer at NASA Johnson Space Center. Initial studies involved the in vitro culture of human peripheral blood mononuclear in cells in different conditioned culture media. Several human cancer clones were similarly studied to determine responses to aberrant glycosylation by the argon laser. The cells were grown at unit gravity in flasks and in simulated microgravity using NASA bioreactors. The cells in each instance were analyzed by flow cytometry. Cell cycle analysis was acquired by staining nuclear DNA with propidium iodide. Responses to the laser stimulation was measured by observing autofluorescence emitted in the green and red spectra after stimulation. Extent of glycosylation correlated with the intensity of the laser stimulated auto-fluorescence. Our particular study was to detect and monitor aberrant glycosylation and its role in etiopathogenesis. Comparisons were made between cells known to be neoplastic and normal cell controls using the same Laser Induced Autofluorescence technique. Studies were begun after extensive literature searches on using the antigen presenting potential of dendritic cells to induce proliferation of antigen specific cytotoxic T-cells. The Sendai virus served as the antigen. Our goal is to generate sufficient numbers of such cells in the simulated microgravity environment for use in autologous transplants of virally infected individuals including those positive for hepatitis and HIV.

Higher skin autofluorescence in young people with Type 1 diabetes and microvascular complications.

PubMed

Cho, Y H; Craig, M E; Januszewski, A S; Benitez-Aguirre, P; Hing, S; Jenkins, A J; Donaghue, K C

2017-04-01

To test the hypothesis that non-invasive skin autofluorescence, a measure of advanced glycation end products, would provide a surrogate measure of long-term glycaemia and be associated with early markers of microvascular complications in adolescents with Type 1 diabetes. Forearm skin autofluorescence (arbitrary units) was measured in a cross-sectional study of 135 adolescents with Type 1 diabetes [mean ± sd age 15.6 ± 2.1 years, diabetes duration 8.7 ± 3.5 years, HbA 1c 72 ± 16 mmol/mol (8.7 ± 1.5%)]. Retinopathy, assessed using seven-field stereoscopic fundal photography, was defined as ≥1 microaneurysm or haemorrhage. Cardiac autonomic function was measured by standard deviation of consecutive RR intervals on a 10-min continuous electrocardiogram recording, as a measure of heart rate variability. Skin autofluorescence was significantly associated with age (R 2 = 0.15; P < 0.001). Age- and gender-adjusted skin autofluorescence was associated with concurrent HbA 1c (R 2 = 0.32; P < 0.001) and HbA 1c over the previous 2.5-10 years (R 2 = 0.34-0.43; P < 0.002). Age- and gender-adjusted mean skin autofluorescence was higher in adolescents with retinopathy vs those without retinopathy [mean 1.38 (95% CI 1.29, 1.48) vs 1.22 (95% CI 1.17, 1.26) arbitrary units; P = 0.002]. In multivariable analysis, retinopathy was significantly associated with skin autofluorescence, adjusted for duration (R 2 = 0.19; P = 0.03). Cardiac autonomic dysfunction was also independently associated with skin autofluorescence (R 2 = 0.11; P = 0.006). Higher skin autofluorescence is associated with retinopathy and cardiac autonomic dysfunction in adolescents with Type 1 diabetes. The relationship between skin autofluorescence and previous glycaemia may provide insight into metabolic memory. Longitudinal studies will determine the utility of skin autofluorescence as a non-invasive screening tool to predict future microvascular complications. © 2016 Diabetes UK.

Autofluorescence guided diagnostic evaluation of suspicious oral mucosal lesions: opportunities, limitations, and pitfalls

NASA Astrophysics Data System (ADS)

Vigneswaran, Nadarajah

2011-03-01

Wide-filed autofluorescence examination is currently considered as a standard of care for screening and diagnostic evaluation of early neoplastic changes of the skin, cervix, lung, bladder, gastrointestinal tract and oral cavity. Naturally occurring fluorophores within the tissue absorb UV and visible light and can re-emit some of this light at longer wavelengths in the form of fluorescence. This non-invasive tissue autofluorescence imaging is used in optical diagnostics, especially in the early detection of cancer. Usually, malignant transformation is associated with thickening of the epithelium, enhanced cellular density due to increased nuclear cytoplasmic ratio which may attenuate the excitation leading to a decrease in collagen autofluorescence. Hence, dysplastic and cancerous tissues often exhibit decreased blue-green autofluorescence and appear darker compared to uninvolved mucosa. Currently, there are three commercially available devices to examine tissue autofluorescence in the oral cavity. In this study we used the oral cancer screening device IdentafiTM 3000 to examine the tissue reflectance and autofluorescence of PML and confounding lesions of the oral cavity. Wide-field autofluorescence imaging enables rapid inspection of large mucosal surfaces, to aid in recognition of suspicious lesions and may also help in discriminate the PML (class 1) from some of the confounding lesions (class II). However, the presence of inflammation or pigments is also associated with loss of stromal autofluorescence, and may give rise to false-positive results with widefield fluorescence imaging. Clinicians who use these autofluorescence based oral cancer screening devices should be aware about the benign oral mucosal lesions that may give false positivity so that unnecessary patient's anxiety and the need for scalpel biopsy can be eliminated.

PATTERNS OF FUNDUS AUTOFLUORESCENCE DEFECTS IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION SUBTYPES.

PubMed

Ozkok, Ahmet; Sigford, Douglas K; Tezel, Tongalp H

2016-11-01

To test define characteristic fundus autofluorescence patterns of different exudative age-related macular degeneration subtypes. Cross-sectional study. Fifty-two patients with choroidal neovascularization because of three different neovascular age-related macular degeneration subtypes were included in the study. Macular and peripheral fundus autofluorescence patterns of study subjects were compared in a masked fashion. Fundus autofluorescence patterns of all three neovascular age-related macular degeneration subtypes revealed similar patterns. However, peripapillary hypo-autofluorescence was more common among patients with polypoidal choroidal vasculopathy (88.2%) compared with patients with retinal angiomatous proliferation (12.5%) and patients without retinal angiomatous proliferation and polypoidal choroidal vasculopathy (21.1%) (P < 0.0001). Presence of peripapillary fundus autofluorescence defects in neovascular age-related macular degeneration maybe suggestive of polypoidal choroidal vasculopathy as a variant of neovascular age-related macular degeneration.

Statistical and fractal analysis of autofluorescent myocardium images in posthumous diagnostics of acute coronary insufficiency

NASA Astrophysics Data System (ADS)

Boichuk, T. M.; Bachinskiy, V. T.; Vanchuliak, O. Ya.; Minzer, O. P.; Garazdiuk, M.; Motrich, A. V.

2014-08-01

This research presents the results of investigation of laser polarization fluorescence of biological layers (histological sections of the myocardium). The polarized structure of autofluorescence imaging layers of biological tissues was detected and investigated. Proposed the model of describing the formation of polarization inhomogeneous of autofluorescence imaging biological optically anisotropic layers. On this basis, analytically and experimentally tested to justify the method of laser polarimetry autofluorescent. Analyzed the effectiveness of this method in the postmortem diagnosis of infarction. The objective criteria (statistical moments) of differentiation of autofluorescent images of histological sections myocardium were defined. The operational characteristics (sensitivity, specificity, accuracy) of these technique were determined.

Detailed histological structure of human hair follicle bulge region at different ages: a visible niche for nesting adult stem cells.

PubMed

Wang, Xiong; Shi, Ying; Zhou, Qiong; Liu, Xiaoming; Xu, Shizheng; Lei, Tiechi

2012-10-01

In the bulge region of the hair follicle, a densely and concentrically packed cell mass is encircled by the arrector pili muscle (APM), which offers a specilized microenvironment (niche) for housing heterogeneous adult stem cells. However, the detailed histological architecture and the cellular composition of the bulge region warrants intensive study and may have implications for the regulation of hair follicle growth regulation. This study was designed to define the gene-expression profiles of putative stem cells and lineage-specific precursors in the mid-portions of plucked hair follicles prepared according to the presence of detectable autofluorescence. The structure was also characterized by using a consecutive sectioning technique. The bulge region of the hair follicle with autofluorescence was precisely excised by employing a micro-dissection procedure. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was performed to identify the gene expression profiles specific for epithelial, melanocyte and stromal stem cells in the bulge region of the hair follicle visualized by autofluorescence. The morphology and its age-dependent changes of bulge region of the hair follicles with autofluorescence segment were also examined in 9 scalp skin specimens collected from patients aged 30 weeks to 75 years, by serial sectioning and immuno-staining. Gene expression profile analysis revealed that there were cells with mRNA transcripts of Dct(Hi)Tyrase(Lo)-Tyrp1(Lo)MC1R(Lo)MITF(Lo)/K15(Hi)/NPNT(Hi) in the bulge region of the hair follicle with autofluorescence segments, which differed from the patterns in hair bulbs. Small cell-protrusions that sprouted from the outer root sheath (ORS) were clearly observed at the APM inserting level in serial sections of hair follicles by immunohistological staining, which were characteristically replete with K15+/K19+expressing cells. Likewise, the muscle bundles of APM positive for smooth muscle actin intimately encircled these cell-protrusions, and the occurrence frequency of the cell-protrusions was increased in fetal scalp skin compared with adult scalp skin. This study provided the evidence that the cell-protrusions occurring at the ORS relative to the APM insertion are more likely to be characteristic of the visible niches that are filled with abundant stem cells. The occurrence frequency of these cell-protrusions was significantly increased in fetal scalp skin samples (128%) as compared with the scalp skins of younger (49.4%) and older (25.4%) adults (P<0.01), but difference in the frequency between the two adult groups were not significant. These results indicated that these cell-protrusions function as a niche house for the myriad stem cells and/or precursors to meet the needs of the development of hair follicles in an embryo. The micro-dissection used in this study was simple and reliable in excising the bulge region of the hair follicle with autofluorescence segments dependent on their autofluorescence is of value for the study of stem cell culture.

Laser-induced dental caries and plaque diagnosis on patients by sensitive autofluorescence spectroscopy and time-gated video imaging: preliminary studies

NASA Astrophysics Data System (ADS)

Koenig, Karsten; Schneckenburger, Herbert

1994-09-01

The laser-induced in vivo autofluorescence of human teeth was investigated by means of time- resolved/time-gated fluorescence techniques. The aim of these studies was non-contact caries and plaque detection. Carious lesions and dental plaque fluoresce in the red spectral region. This autofluorescence seems to be based on porphyrin-producing bacteria. We report on preliminary studies on patients using a novel method of autofluorescence imaging. A special device was constructed for time-gated video imaging. Nanosecond laser pulses for fluorescence excitation were provided by a frequency-doubled, Q-switched Nd:YAG laser. Autofluorescence was detected in an appropriate nanosecond time window using a video camera with a time-gated image intensifier (minimal time gate: 5 ns). Laser-induced autofluorescence based on porphyrin-producing bacteria seems to be an appropriate tool for detecting dental lesions and for creating `caries-images' and `dental plaque' images.

Intensity of Renal Support in Critically Ill Patients with Acute Kidney Injury

PubMed Central

2008-01-01

BACKGROUND The optimal intensity of renal-replacement therapy in critically ill patients with acute kidney injury is controversial. METHODS We randomly assigned critically ill patients with acute kidney injury and failure of at least one nonrenal organ or sepsis to receive intensive or less intensive renal-replacement therapy. The primary end point was death from any cause by day 60. In both study groups, hemodynamically stable patients underwent intermittent hemodialysis, and hemodynamically unstable patients underwent continuous venovenous hemodiafiltration or sustained low-efficiency dialysis. Patients receiving the intensive treatment strategy underwent intermittent hemodialysis and sustained low-efficiency dialysis six times per week and continuous venovenous hemodiafiltration at 35 ml per kilogram of body weight per hour; for patients receiving the less-intensive treatment strategy, the corresponding treatments were provided thrice weekly and at 20 ml per kilogram per hour. RESULTS Baseline characteristics of the 1124 patients in the two groups were similar. The rate of death from any cause by day 60 was 53.6% with intensive therapy and 51.5% with less-intensive therapy (odds ratio, 1.09; 95% confidence interval, 0.86 to 1.40; P = 0.47). There was no significant difference between the two groups in the duration of renalreplacement therapy or the rate of recovery of kidney function or nonrenal organ failure. Hypotension during intermittent dialysis occurred in more patients randomly assigned to receive intensive therapy, although the frequency of hemodialysis sessions complicated by hypotension was similar in the two groups. CONCLUSIONS Intensive renal support in critically ill patients with acute kidney injury did not decrease mortality, improve recovery of kidney function, or reduce the rate of nonrenal organ failure as compared with less-intensive therapy involving a defined dose of intermittent hemodialysis three times per week and continuous renal-replacement therapy at 20 ml per kilogram per hour. (ClinicalTrials.gov number, NCT00076219.) PMID:18492867

Relevance of wide-field autofluorescence imaging in Birdshot retinochoroidopathy: descriptive analysis of 76 eyes.

PubMed

Piffer, Anne-Laure Le; Boissonnot, Michèle; Gobert, Frédéric; Zenger, Anita; Wolf, Sebastian; Wolf, Ute; Korobelnik, Jean-François; Rougier, Marie-Bénédicte

2014-09-01

To study and classify retinal lesions in patients with birdshot disease using wide-field autofluorescence imaging and correlate them according to patients' visual status. A multicentre study was carried out on 76 eyes of 39 patients with birdshot disease, analysing colour images and under autofluorescence using the wide-field Optomap(®) imaging system. This was combined with a complete clinical exam and analysis of the macula with OCT. In over 80% of the eyes, a chorioretinal lesion has been observed under autofluorescence with a direct correlation between the extent of the lesion and visual status. The presence of macular hypo-autofluorescence was correlated with a decreased visual acuity, due to the presence of a macular oedema, active clinical inflammation or an epiretinal membrane. The hypo-autofluorescence observed correlated with the duration of the disease and the degree of inflammation in the affected eye, indicating a secondary lesion in the pigment epithelium in relation to the choroid. The pigment epithelium was affected in a diffuse manner, as in almost 50% of the eyes the wider peripheral retina was affected. Wide-field autofluorescence imaging could appear to be a useful examination when monitoring patients, to look for areas of macular hypo-autofluorescence responsible for an irreversible loss of vision. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

The influence of indoxyl sulfate and ammonium on the autofluorescence of human urine.

PubMed

Perinchery, Sandeep Menon; Kuzhiumparambil, Unnikrishnan; Vemulpad, Subramanyam; Goldys, Ewa M

2010-01-15

Despite biological variability the spectral characteristics of undiluted human urine show relatively low autofluorescence at short UV (250-300nm) excitation. However with dilution the fluorescence intensity remarkably increases. This paper examines the mechanisms behind this effect, by using excitation-emission matrices. Corrections for the inner filter effect were made for improved understanding of the spectral patterns. We focused on three major fluorophores (tryptophan, indoxyl sulfate and 5-hydroxyindole-3-acetate) that are excited at these wavelengths, and whose content in urine is strongly linked with various health conditions. Their fluorescence was studied both individually and in combinations. We also examined the effect of ammonium on the fluorescence of these major fluorophores individually and in combinations. Through these studies we have identified the leading effects that reduce the UV fluorescence, namely higher concentration of indoxyl sulfate producing the inner filter effect and concentration quenching and quenching of fluorophores by ammonium. This result will assist in broader utilisation of UV fluorescence in medical diagnostics.

Detection of early metabolic alterations in the ocular fundus of diabetic patients by time-resolved autofluorescence of endogenous fluorophores

NASA Astrophysics Data System (ADS)

Schweitzer, D.; Klemm, M.; Quick, S.; Deutsch, L.; Jentsch, S.; Hammer, M.; Dawczynski, J.; Kloos, C. H.; Mueller, U. A.

2011-07-01

Measurements of time-resolved autofluorescence (FLIM) at the human ocular fundus of diabetic patients permit the detection of early pathologic alterations before signs of diabetic retinopathy are visible. The measurements were performed by the Jena Fluorescence Lifetime Laser Scanner Ophthalmoscope applying time-correlated single photon counting (TCSPC) in two spectral channels (K1: 490-560 nm, K2:560-700ps). The fluorescence was excited by 70 ps pulses (FWHM) at 448 nm. The decay of fluorescence intensity was triple-exponentially approximated. The frequency of amplitudes, lifetimes, and relative contributions was compared in fields of the same size and position in healthy subjects and in diabetic patients. The most sensitive parameter was the lifetime T2 in the short-wavelength channel, which corresponds to the neuronal retina. The changes in lifetime point to a loss of free NADH and an increased contribution of protein-bound NADH in the pre-stage of diabetic retinopathy.

Agricultural pest monitoring using fluorescence lidar techniques. Feasibility study

NASA Astrophysics Data System (ADS)

Mei, L.; Guan, Z. G.; Zhou, H. J.; Lv, J.; Zhu, Z. R.; Cheng, J. A.; Chen, F. J.; Löfstedt, C.; Svanberg, S.; Somesfalean, G.

2012-03-01

The fluorescence of different types of planthopper ( Hemiptera) and moth ( Lepidoptera), which constitute important Chinese agricultural pests, was investigated both in situ in a laboratory setting and remotely using a fluorescence light detection and ranging (lidar) system operating at a range of about 50 m. The natural autofluorescence of different species, as well as the fluorescence from insects that had been dusted with fluorescent dye powder for identification were studied. Autofluorescence spectra of both moths and planthoppers show a maximum intensity peak around 450 nm. Bleaching upon long-time laser illumination was modest and did not affect the shape of the spectrum. A single dyed rice planthopper, a few mm in size, could be detected at 50 m distance by using the fluorescence lidar system. By employing various marking dyes, different types of agricultural pest could be determined. We suggest that lidar may be used in studies of migration and movement of pest insects, including studies of their behavior in the vicinity of pheromone traps and in pheromone-treated fields.

Investigate the variation in optical redox ratio of epicardial adipose tissue in patients with CAD through auto-fluorescence metabolic molecular image (Conference Presentation)

NASA Astrophysics Data System (ADS)

Guo, Lun-Zhang; Wang, Tzung-Dau; Lin, Jong-Wei; Liu, Tzu-Ming

2016-04-01

In recent years, it has been suggested that epicardial adipose tissue (EAT) plays an important role in development of coronary artery disease (CAD) and diabetes mellitus (DM). In this article, we used two-photon fluoresce microscope to measure the fluorescence metabolic image of EAT, which obtained from the patient with/without CAD/DM. We used 740nm and 890nm infrared light to excite the auto-fluorescence of metabolic molecules NADH and FAD respectively. We collected the fluorescence signal at wavelength 450nm to 500nm and 500nm to 550nm to obtain the metabolic image. Through the image, we computed the redox ratio (NADH/FAD) by analyzing the intensity. The preliminary result showed that the redox ratio increase in the patients with CAD. It indicates EAT adipocytes of patient with CAD have decreased cellular metabolic activity. But there were no significant variation of redox ratio in the patients with DM.

Early simultaneous fundus autofluorescence and optical coherence tomography features after pars plana vitrectomy for primary rhegmatogenous retinal detachment.

PubMed

Dell'Omo, Roberto; Mura, Marco; Lesnik Oberstein, Sarit Y; Bijl, Heico; Tan, H Stevie

2012-04-01

To describe fundus autofluorescence and optical coherence tomography (OCT) features of the macula after pars plana vitrectomy for rhegmatogenous retinal detachment. Thirty-three eyes of 33 consecutive patients with repaired rhegmatogenous retinal detachment with or without the involvement of the macula were prospectively investigated with simultaneous fundus autofluorescence and OCT imaging using the Spectralis HRA+OCT (Heidelberg Engineering, Heidelberg, Germany) within a few weeks after the operation. Fundus autofluorescence imaging of the macula showed lines of increased and decreased autofluorescence in 19 cases (57.6%). On OCT, these lines corresponded to the following abnormalities: outer retinal folds, inner retinal folds, and skip reflectivity abnormalities of the photoreceptor inner segment/outer segment band. Other OCT findings, not related to abnormal lines on fundus autofluorescence, consisted of disruption of photoreceptor inner segment/outer segment band and collection of intraretinal or subretinal fluid. The presence of outer retinal folds significantly related to metamorphopsia but did not relate to poor postoperative visual acuity. Partial-thickness retinal folds occur commonly after vitrectomy for rhegmatogenous retinal detachment repair and may represent an important anatomical substrate for postoperative metamorphopsia. Fundus autofluorescence and OCT are both sensitive techniques for the detection of these abnormalities.

Usefulness of tissue autofluorescence imaging in actinic cheilitis diagnosis.

PubMed

Takahama Junior, Ademar; Kurachi, Cristina; Cosci, Alessandro; Pereira Faustino, Isabel Schausltz; Camisasca, Danielle Resende; da Costa Fontes, Karla Bianca Fernandes; Pires, Fábio Ramôa; Azevedo, Rebeca Souza

2013-07-01

Actinic cheilitis (AC) is a potentially malignant disorder of the lips. Because of its heterogeneous clinical aspect, it is difficult to indicate representative biopsy area. The purpose of this study was to evaluate the usefulness of tissue autofluorescence in AC diagnosis. The system was composed of a 405-nm light-emitting diode, sent to the sample by a dichroic, that allows the fluorescence signal to reach a camera directly plugged in the system. Fifty-seven patients with clinical diagnosis of AC and 45 normal volunteers were selected. According to clinical and fluorescence features, one or more areas were selected for biopsies in the AC group and epithelial dysplasia (ED) grades were established. The autofluorescence images were processed by a clustering algorithm for AC automated diagnosis. The tissue autofluorescence image revealed a heterogeneous pattern of loss and increase of fluorescence in patients with AC. ED was found in 93% of the cases, and most of the areas graded as moderate or severe ED were chosen with the aid of autofluorescence. The processed autofluorescence images from AC patients showed a higher number of spots in an irregular pattern. Tissue autofluorescence image system is a useful technique in association with clinical examination for AC diagnosis.

Narrow band imaging versus autofluorescence imaging for head and neck squamous cell carcinoma detection: a prospective study.

PubMed

Ni, X-G; Zhang, Q-Q; Wang, G-Q

2016-11-01

This study aimed to compare the diagnostic effectiveness of narrow band imaging and autofluorescence imaging for malignant laryngopharyngeal tumours. Between May 2010 and October 2010, 50 consecutive patients with suspected laryngopharyngeal tumour underwent endoscopic laryngopharynx examination. The morphological characteristics of laryngopharyngeal lesions were analysed using high performance endoscopic systems equipped with narrow band imaging and autofluorescence imaging modes. The diagnostic effectiveness of white light image, narrow band imaging and autofluorescence imaging endoscopy for benign and malignant laryngopharyngeal lesions was evaluated. Under narrow band imaging endoscopy, the superficial microvessels of squamous cell carcinomas appeared as dark brown spots or twisted cords. Under autofluorescence imaging endoscopy, malignant lesions appeared as bright purple. The sensitivity of malignant lesion diagnosis was not significantly different between narrow band imaging and autofluorescence imaging modes, but was better than for white light image endoscopy (χ2 = 12.676, p = 0.002). The diagnostic specificity was significantly better in narrow band imaging mode than in both autofluorescence imaging and white light imaging mode (χ2 = 8.333, p = 0.016). Narrow band imaging endoscopy is the best option for the diagnosis and differential diagnosis of laryngopharyngeal tumours.

Autofluorescence and non-specific immunofluorescent labeling in frozen bovine intestinal tissue sections: Solutions for multi-color immunofluorescence experiments

USDA-ARS?s Scientific Manuscript database

Autofluorescence and non-specific immunofluorescent labeling are common challenges associated with immunofluorescence experiments. Autofluorescence typically demonstrates a broad emission spectrum, increasing the potential for overlap with experiments that utilize multiple fluorophores. During immun...

Optical detection of (pre-)malignant lesions of the oral mucosa: autofluorescence characteristics of healthy mucosa

NASA Astrophysics Data System (ADS)

de Veld, Diana C. G.; Witjes, Max; Roodenburg, Jan L.; Star, Willem M.; Sterenborg, Hericus J. C. M.

2001-10-01

Previous clinical results demonstrate the potential of in vivo autofluorescence spectroscopy for early detection of (pre-)malignant lesions of the oral mucosa. For reliable diagnosis, it is necessary to study autofluorescence spectra of healthy mucosa first. We measured excitation-emission maps in healthy subjects and subjects with a history of cancer in the head -neck region. Our results show that different anatomical locations produce distinct autofluorescence spectra. Influences of, among others, smoking and drinking habits require further investigation.

Prevention of increased abnormal fundus autofluorescence with blue light-filtering intraocular lenses.

PubMed

Nagai, Hiroyuki; Hirano, Yoshio; Yasukawa, Tsutomu; Morita, Hiroshi; Nozaki, Miho; Wolf-Schnurrbusch, Ute; Wolf, Sebastian; Ogura, Yuichiro

2015-09-01

To observe changes in fundus autofluorescence 2 years after implantation of blue light-filtering (yellow-tinted) and ultraviolet light-filtering (colorless) intraocular lenses (IOLs). Department of Ophthalmology and Visual Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan, and the Department of Ophthalmology, University of Bern, Bern, Switzerland. Prospective comparative observational study. Patients were enrolled who had cataract surgery with implantation of a yellow-tinted or colorless IOL and for whom images were obtained on which the fundus autofluorescence was measurable using the Heidelberg Retina Angiogram 2 postoperatively. The fundus autofluorescence in the images was classified into 8 abnormal patterns based on the classification of the International Fundus Autofluorescence Classification Group, The presence of normal fundus autofluorescence, geographic atrophy, and wet age-related macular degeneration (AMD) also was recorded. The fundus findings at baseline and 2 years postoperatively were compared. Fifty-two eyes with a yellow-tinted IOL and 79 eyes with a colorless IOL were included. Abnormal fundus autofluorescence did not develop or increase in the yellow-tinted IOL group; however, progressive abnormal fundus autofluorescence developed or increased in 12 eyes (15.2%) in the colorless IOL group (P = .0016). New drusen, geographic atrophy, and choroidal neovascularization were observed mainly in the colorless IOL group. The incidence of AMD was statistically significantly higher in the colorless IOL group (P = .042). Two years after cataract surgery, significant differences were seen in the progression of abnormal fundus autofluorescence between the 2 groups. The incidence of AMD was lower in eyes with a yellow-tinted IOL. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Skin autofluorescence and all-cause mortality in stage 3 CKD.

PubMed

Fraser, Simon D S; Roderick, Paul J; McIntyre, Natasha J; Harris, Scott; McIntyre, Christopher W; Fluck, Richard J; Taal, Maarten W

2014-08-07

Novel markers may help to improve risk prediction in CKD. One potential candidate is tissue advanced glycation end product accumulation, a marker of cumulative metabolic stress, which can be assessed by a simple noninvasive measurement of skin autofluorescence. Skin autofluorescence correlates with higher risk of cardiovascular events and mortality in people with diabetes or people requiring RRT, but its role in earlier CKD has not been studied. A prospective cohort of 1741 people with CKD stage 3 was recruited from primary care between August 2008 and March 2010. Participants underwent medical history, clinical assessment, blood and urine sampling for biochemistry, and measurement of skin autofluorescence. Kaplan-Meier plots and multivariate Cox proportional hazards models were used to investigate associations between skin autofluorescence (categorical in quartiles) and all-cause mortality. In total, 1707 participants had skin autofluorescence measured; 170 (10%) participants died after a median of 3.6 years of follow-up. The most common cause of death was cardiovascular disease (41%). Higher skin autofluorescence was associated significantly with poorer survival (all-cause mortality, P<0.001) on Kaplan-Meier analysis. Univariate and age/sex-adjusted Cox proportional hazards models showed that the highest quartile of skin autofluorescence was associated with all-cause mortality (hazard ratio, 2.64; 95% confidence interval, 1.71 to 4.08; P<0.001 and hazard ratio, 1.84; 95% confidence interval, 1.18 to 2.86; P=0.003, respectively, compared with the lowest quartile). This association was not maintained after additional adjustment to include cardiovascular disease, diabetes, smoking, body mass index, eGFR, albuminuria, and hemoglobin. Skin autofluorescence was not independently associated with all-cause mortality in this study. Additional research is needed to clarify whether it has a role in risk prediction in CKD. Copyright © 2014 by the American Society of Nephrology.

Polarimetric imaging of retinal disease by polarization sensitive SLO

NASA Astrophysics Data System (ADS)

Miura, Masahiro; Elsner, Ann E.; Iwasaki, Takuya; Goto, Hiroshi

2015-03-01

Polarimetry imaging is used to evaluate different features of the macular disease. Polarimetry images were recorded using a commercially- available polarization-sensitive scanning laser opthalmoscope at 780 nm (PS-SLO, GDx-N). From data sets of PS-SLO, we computed average reflectance image, depolarized light images, and ratio-depolarized light images. The average reflectance image is the grand mean of all input polarization states. The depolarized light image is the minimum of crossed channel. The ratio-depolarized light image is a ratio between the average reflectance image and depolarized light image, and was used to compensate for variation of brightness. Each polarimetry image is compared with the autofluorescence image at 800 nm (NIR-AF) and autofluorescence image at 500 nm (SW-AF). We evaluated four eyes with geographic atrophy in age related macular degeneration, one eye with retinal pigment epithelium hyperplasia, and two eyes with chronic central serous chorioretinopathy. Polarization analysis could selectively emphasize different features of the retina. Findings in ratio depolarized light image had similarities and differences with NIR-AF images. Area of hyper-AF in NIR-AF images showed high intensity areas in the ratio depolarized light image, representing melanin accumulation. Areas of hypo-AF in NIR-AF images showed low intensity areas in the ratio depolarized light images, representing melanin loss. Drusen were high-intensity areas in the ratio depolarized light image, but NIR-AF images was insensitive to the presence of drusen. Unlike NIR-AF images, SW-AF images showed completely different features from the ratio depolarized images. Polarization sensitive imaging is an effective tool as a non-invasive assessment of macular disease.

Fundus autofluorescence imaging patterns in central serous chorioretinopathy according to chronicity.

PubMed

Lee, W J; Lee, J-H; Lee, B R

2016-10-01

PurposeTo investigate the time-period characteristics associated with morphologic changes in central serous chorioretinopathy (CSC) using fundus autofluorescence (FAF).Patients and methodsRetrospective, cross-sectional observational case series. Patients were classified into three groups: acute and chronic according to the onset of subjective symptoms of 6 weeks and sequelae patients who have history and symptoms but no serous retinal detachment (SRD). We compared FAF images to obtain characteristic findings according to the chronicity.ResultsA total of 52 eyes were included in this study. Acute CSC eyes were characterized by decreased FAF intensity at the leakage point in 13/22 eyes (56.5%) and staining patterns with various levels of fluorescence signal (hyperautofluorescent (10 eyes, 43.5%), hypoautofluorescent (1 eye, 4.3%), and minimal changes (12 eyes, 52.2%)) in the area of SRD. In chronic CSC eyes, hyperautofluorescent (14 eyes, 63.6%) or minimal changes (8 eyes, 36.4%) were observed in the area of SRD. Discrete dots with increased FAF intensity were observed in chronic CSC eyes (P<0.001). Eyes with sequelae of CSC had mixed FAF patterns over areas of retinal pigment epithelium (RPE) atrophy in seven eyes (100%, P<0.001)) and descending tracts which showed various FAF intensities according to the RPE and photoreceptor status (P<0.001).ConclusionFAF imaging patterns in CSC eyes differ according to the course of the disease, reflecting RPE and outer retinal changes. Detailed investigation using FAF could help to estimate the duration of CSC and determine the proper treatment modality.

Autofluorescence spectroscopy of oral mucosa

NASA Astrophysics Data System (ADS)

Majumdar, S. K.; Uppal, A.; Gupta, P. K.

1998-06-01

We report the results of an in-vitro study on autofluorescence from pathologically characterized normal and malignant squamous tissues from the oral cavity. The study involved biopsy samples from 47 patients with oral cancer of which 11 patients had cancer of tongue, 17 of buccal mucosa and 19 of alveolus. The results of excitation and emission spectroscopy at several wavelengths (280 nm less than or equal to (lambda) exless than or equal to 460 nm; 340 nm less than or equal to (lambda) em less than or equal to 520 nm) showed that at (lambda) ex equals 337 nm and 400 nm the mean value for the spectrally integrated fluorescence intensity [(Sigma) (lambda ) IF((lambda) )] from the normal tissue sites was about a factor of 2 larger than that from the malignant tissue sites. At other excitation wavelengths the difference in (Sigma) (lambda ) IF((lambda) ) was not statistically significant. Similarly, for (lambda) em equals 390 nm and 460 nm, the intensity of the 340 nm band of the excitation spectra from normal tissues was observed to be a factor of 2 larger than that from malignant tissues. Analysis of these results suggests that NADH concentration is higher in normal oral tissues compared to the malignant. This contrasts with our earlier observation of an reduced NADH concentration in normal sites of breast tissues vis a vis malignant sites. For the 337 nm excited emission spectra a 10-variable MVLR score (using (Sigma) (lambda ) IF((lambda) ) and normalized intensities at nine wavelengths as input parameters) provided a sensitivity and specificity of 95.7% and 93.1% over the sample size investigated.

Combining large area fluorescence with multiphoton microscopy for improved detection of oral epithelial neoplasia (Conference Presentation)

NASA Astrophysics Data System (ADS)

Pal, Rahul; Yang, Jinping; Qiu, Suimin; McCammon, Susan; Resto, Vicente; Vargas, Gracie

2016-03-01

Volumetric Multiphoton Autofluorescence Microscopy (MPAM) and Second Harmonic Generation Microscopy (SHGM) show promise for revealing indicators of neoplasia representing the complex microstructural organization of mucosa, potentially providing high specificity for detection of neoplasia, but is limited by small imaging area. Large area fluorescence methods on the other hand show high sensitivity appropriate for screening but are hampered by low specificity. In this study, we apply MPAM-SHGM following guidance from large area fluorescence, by either autofluorescence or a targeted metabolic fluorophore, as a potentially clinically viable approach for detection of oral neoplasia. Sites of high neoplastic potentially were identified by large area red/green autofluorescence or by a fluorescently labelled deoxy-glucose analog, 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-D-glucose (2-NBDG) to highlight areas of high glucose uptake across the buccal pouch of a hamster model for OSCC. Follow-up MPAM-SHGM was conducted on regions of interests (ROIs) to assess whether microscopy would reveal microscopic features associated with neoplasia to confirm or exclude large area fluorescence findings. Parameters for analysis included cytologic metrics, 3D epithelial connective tissue interface metrics (MPAM-SHGM) and intensity of fluorescence (widefield). Imaged sites were biopsied and processed for histology and graded by a pathologist. A small sample of human ex vivo tissues were also imaged. A generalized linear model combining image metrics from large area fluorescence and volumetric MPAM-SHGM indicated the ability to delineate normal and inflammation from neoplasia.

Spectral (optical) and mechanical responses of fresh and cryopreserved issued arteries

NASA Astrophysics Data System (ADS)

Pery, Emilie; Blondel, Walter C.; Goebel, Jean-Christophe; Didelon, Jacques; Guillemin, Francois

2005-04-01

Cryopreservation is the only method for conserving blood vessels as future allografts with biological immunity controls. Although it affects vessels mechanical structure, no biomechanical integrity simple test is available today. Biological tissues optical properties characterization by spectroscopic methods is of interest due to their types or natures variations. Collected data complementarity contributes to "photodiagnosis" applicative prospects (cancer, vascular...). Pig carotid artery rings were tested after excision and after one month cryopreservation. An uniaxial mechanical testing device was used for ring stretching, and elongation and axial forces measurement. Circumferential large strains and stresses were calculated. Simultaneously, each artery ring optical characteristics was measured using fibered autofluorescence and elastic scattering spectrometers. Mechanical results showed nonlinear strain/stress curves and large deformations in good agreement with other referenced works. Significant differences (p<0.05) between fresh and cryopreserved rings mechanical properties were noticed. Elastic scattering spectra intensity variations were well correlated with artery mechanical properties. The standardized autofluorescence spectra were more clearly correlated with anatomo-histological changes due to cryopreservation, providing rather accurate differentiation between fresh and cryopreserved samples. This study offers a new perspective to detect changes of cryopreserved arterial samples mechanical properties. Coupling mechanical tests (uniaxial traction of arterial rings) and optical spectroscopic measurements (autofluorescence, elastic scattering) is the driving point: it allows correlating mechanical modifications and spectral variations of artery rings before and after cryopreservation. Ultimately, this new approach could help developping a device allowing non-invasive, atraumatic and contactless optical examinations of arterial graft to assess its mechanical state before reimplantation.

Intensive Blood-Pressure Control in Hypertensive Chronic Kidney Disease

PubMed Central

Appel, Lawrence J.; Wright, Jackson T.; Greene, Tom; Agodoa, Lawrence Y.; Astor, Brad C.; Bakris, George L.; Cleveland, William H.; Charleston, Jeanne; Contreras, Gabriel; Faulkner, Marquetta L.; Gabbai, Francis B.; Gassman, Jennifer J.; Hebert, Lee A.; Jamerson, Kenneth A.; Kopple, Joel D.; Kusek, John W.; Lash, James P.; Lea, Janice P.; Lewis, Julia B.; Lipkowitz, Michael S.; Massry, Shaul G.; Miller, Edgar R.; Norris, Keith; Phillips, Robert A.; Pogue, Velvie A.; Randall, Otelio S.; Rostand, Stephen G.; Smogorzewski, Miroslaw J.; Toto, Robert D.; Wang, Xuelei

2013-01-01

BACKGROUND In observational studies, the relationship between blood pressure and end-stage renal disease (ESRD) is direct and progressive. The burden of hypertension-related chronic kidney disease and ESRD is especially high among black patients. Yet few trials have tested whether intensive blood-pressure control retards the progression of chronic kidney disease among black patients. METHODS We randomly assigned 1094 black patients with hypertensive chronic kidney disease to receive either intensive or standard blood-pressure control. After completing the trial phase, patients were invited to enroll in a cohort phase in which the blood-pressure target was less than 130/80 mm Hg. The primary clinical outcome in the cohort phase was the progression of chronic kidney disease, which was defined as a doubling of the serum creatinine level, a diagnosis of ESRD, or death. Follow-up ranged from 8.8 to 12.2 years. RESULTS During the trial phase, the mean blood pressure was 130/78 mm Hg in the intensive-control group and 141/86 mm Hg in the standard-control group. During the cohort phase, corresponding mean blood pressures were 131/78 mm Hg and 134/78 mm Hg. In both phases, there was no significant between-group difference in the risk of the primary outcome (hazard ratio in the intensive-control group, 0.91; P = 0.27). However, the effects differed according to the baseline level of proteinuria (P = 0.02 for interaction), with a potential benefit in patients with a protein-to-creatinine ratio of more than 0.22 (hazard ratio, 0.73; P = 0.01). CONCLUSIONS In overall analyses, intensive blood-pressure control had no effect on kidney disease progression. However, there may be differential effects of intensive blood-pressure control in patients with and those without baseline proteinuria. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases, the National Center on Minority Health and Health Disparities, and others.) PMID:20818902

Fluid accumulation during acute kidney injury in the intensive care unit.

PubMed

Berthelsen, R E; Perner, A; Jensen, A K; Jensen, J-U; Bestle, M H

2018-07-01

Fluid therapy is a ubiquitous intervention in patients admitted to the intensive care unit, but positive fluid balance may be associated with poor outcomes and particular in patients with acute kidney injury. Studies describing this have defined fluid overload either at specific time points or considered patients with a positive mean daily fluid balance as fluid overloaded. We wished to detail this further and performed joint model analyses of the association between daily fluid balance and outcome represented by mortality and renal recovery in patients admitted with acute kidney injury. We did a retrospective cohort study of patients admitted to the intensive care unit with acute kidney injury during a 2-year observation period. We used serum creatinine measurements to identify patients with acute kidney injury and collected sequential daily fluid balance during the first 5 days of admission to the intensive care unit. We used joint modelling techniques to correlate the development of fluid overload with survival and renal recovery adjusted for age, gender and disease severity. The cohort contained 863 patients with acute kidney injury of whom 460 (53%) and 254 (29%) developed 5% and 10% fluid overload, respectively. We found that both 5% and 10% fluid overload was correlated with reduced survival and renal recovery. Joint model analyses of fluid accumulation in patients admitted to the intensive care unit with acute kidney injury confirm that even a modest degree of fluid overload (5%) may be negatively associated with both survival and renal recovery. © 2018 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Autofluorescence generation and elimination: a lesson from glutaraldehyde.

PubMed

Lee, Kwahun; Choi, Sungmoon; Yang, Chun; Wu, Hai-Chen; Yu, Junhua

2013-04-14

Glutaraldehyde causes especially high autofluorescence. It reacted with proteins and peptides to generate visible to near-IR emitters. A model indicated that ethylenediamine and a secondary amine in the molecule were key components for the formation of emissive species. The mechanism enables us to control the generation and elimination of autofluorescence.

Use of fundus autofluorescence images to predict geographic atrophy progression.

PubMed

Bearelly, Srilaxmi; Khanifar, Aziz A; Lederer, David E; Lee, Jane J; Ghodasra, Jason H; Stinnett, Sandra S; Cousins, Scott W

2011-01-01

Fundus autofluorescence imaging has been shown to be helpful in predicting progression of geographic atrophy (GA) secondary to age-related macular degeneration. We assess the ability of fundus autofluorescence imaging to predict rate of GA progression using a simple categorical scheme. Subjects with GA secondary to age-related macular degeneration with fundus autofluorescence imaging acquired at least 12 months apart were included. Rim area focal hyperautofluorescence was defined as percentage of the 500-μm-wide margin bordering the GA that contained increased autofluorescence. Rim area focal hyperautofluorescence on baseline fundus autofluorescence images was assessed and categorized depending on the extent of rim area focal hyperautofluorescence (Category 1: ≤33%; Category 2: between 33 and 67%; Category 3: ≥67%). Total GA areas at baseline and follow-up were measured to calculate change in GA progression. Forty-five eyes of 45 subjects were included; average duration of follow-up was 18.5 months. Median growth rates differed among categories of baseline rim area focal hyperautofluorescence (P = 0.01 among Categories 1, 2, and 3; P = 0.008 for Category 1 compared with Category 3, Jonckheere-Terpstra test). A simple categorical scheme that stratifies the amount of increased autofluorescence in the 500-μm margin bordering GA may be used to differentiate faster and slower progressors.

Distinction of brain tissue, low grade and high grade glioma with time-resolved fluorescence spectroscopy

PubMed Central

Yong, William H.; Butte, Pramod V.; Pikul, Brian K.; Jo, Javier A.; Fang, Qiyin; Papaioannou, Thanassis; Black, Keith L.; Marcu, Laura

2010-01-01

Neuropathology frozen section diagnoses are difficult in part because of the small tissue samples and the paucity of adjunctive rapid intraoperative stains. This study aims to explore the use of time-resolved laser-induced fluorescence spectroscopy as a rapid adjunctive tool for the diagnosis of glioma specimens and for distinction of glioma from normal tissues intraoperatively. Ten low grade gliomas, 15 high grade gliomas without necrosis, 6 high grade gliomas with necrosis and/or radiation effect, and 14 histologically uninvolved “normal” brain specimens are spectroscopicaly analyzed and contrasted. Tissue autofluorescence was induced with a pulsed Nitrogen laser (337 nm, 1.2 ns) and the transient intensity decay profiles were recorded in the 370-500 nm spectral range with a fast digitized (0.2 ns time resolution). Spectral intensities and time-dependent parameters derived from the time-resolved spectra of each site were used for tissue characterization. A linear discriminant analysis diagnostic algorithm was used for tissue classification. Both low and high grade gliomas can be distinguished from histologically uninvolved cerebral cortex and white matter with high accuracy (above 90%). In addition, the presence or absence of treatment effect and/or necrosis can be identified in high grade gliomas. Taking advantage of tissue autofluorescence, this technique facilitates a direct and rapid investigation of surgically obtained tissue. PMID:16368511

Automated fluorescent miscroscopic image analysis of PTBP1 expression in glioma

PubMed Central

Becker, Aline; Elder, Brad; Puduvalli, Vinay; Winter, Jessica; Gurcan, Metin

2017-01-01

Multiplexed immunofluorescent testing has not entered into diagnostic neuropathology due to the presence of several technical barriers, amongst which includes autofluorescence. This study presents the implementation of a methodology capable of overcoming the visual challenges of fluorescent microscopy for diagnostic neuropathology by using automated digital image analysis, with long term goal of providing unbiased quantitative analyses of multiplexed biomarkers for solid tissue neuropathology. In this study, we validated PTBP1, a putative biomarker for glioma, and tested the extent to which immunofluorescent microscopy combined with automated and unbiased image analysis would permit the utility of PTBP1 as a biomarker to distinguish diagnostically challenging surgical biopsies. As a paradigm, we utilized second resections from patients diagnosed either with reactive brain changes (pseudoprogression) and recurrent glioblastoma (true progression). Our image analysis workflow was capable of removing background autofluorescence and permitted quantification of DAPI-PTBP1 positive cells. PTBP1-positive nuclei, and the mean intensity value of PTBP1 signal in cells. Traditional pathological interpretation was unable to distinguish between groups due to unacceptably high discordance rates amongst expert neuropathologists. Our data demonstrated that recurrent glioblastoma showed more DAPI-PTBP1 positive cells and a higher mean intensity value of PTBP1 signal compared to resections from second surgeries that showed only reactive gliosis. Our work demonstrates the potential of utilizing automated image analysis to overcome the challenges of implementing fluorescent microscopy in diagnostic neuropathology. PMID:28282372

Simple Elimination of Background Fluorescence in Formalin-Fixed Human Brain Tissue for Immunofluorescence Microscopy.

PubMed

Sun, Yulong; Ip, Philbert; Chakrabartty, Avijit

2017-09-03

Immunofluorescence is a common method used to visualize subcellular compartments and to determine the localization of specific proteins within a tissue sample. A great hindrance to the acquisition of high quality immunofluorescence images is endogenous autofluorescence of the tissue caused by aging pigments such as lipofuscin or by common sample preparation processes such as aldehyde fixation. This protocol describes how background fluorescence can be greatly reduced through photobleaching using white phosphor light emitting diode (LED) arrays prior to treatment with fluorescent probes. The broad-spectrum emission of white phosphor LEDs allow for bleaching of fluorophores across a range of emission peaks. The photobleaching apparatus can be constructed from off-the-shelf components at very low cost and offers an accessible alternative to commercially available chemical quenchers. A photobleaching pre-treatment of the tissue followed by conventional immunofluorescence staining generates images free of background autofluorescence. Compared to established chemical quenchers which reduced probe as well as background signals, photobleaching treatment had no effect on probe fluorescence intensity while it effectively reduced background and lipofuscin fluorescence. Although photobleaching requires more time for pre-treatment, higher intensity LED arrays may be used to reduce photobleaching time. This simple method can potentially be applied to a variety of tissues, particularly postmitotic tissues that accumulate lipofuscin such as the brain and cardiac or skeletal muscles.

Clinical uses of autofluorescence in ophthalmology.

PubMed

Baxter, Kim

2017-10-01

Although it has been around for many years, historically autofluorescence has been difficult to capture. Developments in technology and camera sensors have made the process much easier and there is increasing research exploring autofluorescence patterns and how they can be used. This article explores the clinical uses of this technology in monitoring certain retinal conditions.

Correlation between Spectral Optical Coherence Tomography and Fundus Autofluorescence at the margins of Geographic Atrophy

PubMed Central

Brar, Manpreet; Kozak, Igor; Cheng, Lingyun; Bartsch, Dirk-Uwe G.; Yuson, Ritchie; Nigam, Nitin; Oster, Stephen F.; Mojana, Francesca; Freeman, William R.

2009-01-01

Purpose We studied the appearance of margins of Geographic atrophy in high- resolution optical coherence tomography (OCT) images and correlate those changes with fundus autofluorescence imaging. Design Retrospective observational case study. Methods Patients with geographic atrophy secondary to dry age related macular degeneration (ARMD) were assessed by means of Spectral Domain OCT (Spectralis HRA/OCT; Heidelberg Engineering, Heidelberg, Germany or OTI, Inc, Toronto, Canada) as well as Autofluoresence Imaging (HRA or Spectralis Heidelberg Engineering, Heidelberg, Germany): The outer retinal layer alterations were analyzed in the junctional zone between normal retina and atrophic retina, and correlated with corresponding fundus autofluorescence. Results 23 eyes of 16 patients aged between 62 years to 96 years were examined. There was a significant association between OCT findings and the fundus autofluorescence findings(r=0.67, p<0.0001). Severe alterations of the outer retinal layers at margins on Spectral OCT correspond significantly to increased autofluorescence; Smooth margins on OCT correspond significantly to normal fundus autofluorescence. (Kappa-0.7348, p<0.0001). Conclusion Spectral OCT provides in vivo insight into the pathogenesis of geographic atrophy and its progression. Visualization of reactive changes in the retinal pigment epithelial cells at the junctional zone and correlation with increased fundus autofluorescence; secondary to increased lipofuscin may together serve as determinants of progression of geographic atrophy. PMID:19541290

Observation of Zn-photoprotoporphyrin red Autofluorescence in human bronchial cancer using color-fluorescence endoscopy.

PubMed

Ohsaki, Yoshinobu; Sasaki, Takaaki; Endo, Satoshi; Kitada, Masahiro; Okumura, Shunsuke; Hirai, Noriko; Kazebayashi, Yoshihiro; Toyoshima, Eri; Yamamoto, Yasushi; Takeyama, Kaneyoshi; Nakajima, Susumu; Sakata, Isao

2017-04-26

We observed red autofluorescence emanating from bronchial cancer lesions using a sensitive color-fluorescence endoscopy system. We investigated to clarify the origin of the red autofluorescence. The wavelengths of the red autofluorescence emanating from lesions were measured in eight patients using a spectrum analyzer and compared based on pathologic findings. Red autofluorescence at 617.3, 617.4, 619.0, and 617.1 nm was emitted by normal bronchus, inflamed tissue, tissue exhibiting mild dysplasia, and malignant lesions, respectively. Protoporphyrin, uroporphyrin, and coproporphyrin, the major porphyrin derivatives in human blood, were purchased to determine which porphyrin derivative is the source of red fluorescence when acquired de novo. We synthesized photoporphyrin, Zn-protoporphyrin and Zn-photoprotoporphyrin from protoporphyrin. Coproporphyrin and uroporphyrin emitted only weak fluorescence. Fluorescence was emitted by our synthesized Zn-photoprotoporphyrin at 625.5 nm and by photoprotoporphyrin at 664.0 nm. From these results, we conclude that Zn-photoprotoporphyrin was the source of the red autofluorescence observed in bronchial lesions. Zn-protoporphyrin is converted to Zn-photoprotoporphyrin by radiation with excitation light. Our results suggest that red autofluorescence emanating from Zn-photoprotoporphyrin in human tissues could interfere with photodynamic diagnosis using porphyrin derivatives such as Photofrin® and Lazerphyrin® with a sensitive endoscopy system, because color cameras cannot differentiate Zn-photoprotoporphyrin red fluorescence from that of other porphyrin derivatives.

Autofluorescence detection and imaging of bladder cancer realized through a cystoscope

DOEpatents

Demos, Stavros G [Livermore, CA; deVere White, Ralph W [Sacramento, CA

2007-08-14

Near infrared imaging using elastic light scattering and tissue autofluorescence and utilizing interior examination techniques and equipment are explored for medical applications. The approach involves imaging using cross-polarized elastic light scattering and/or tissue autofluorescence in the Near Infra-Red (NIR) coupled with image processing and inter-image operations to differentiate human tissue components.

Skin Autofluorescence and Subclinical Atherosclerosis in Mild to Moderate Chronic Kidney Disease: A Case-Control Study.

PubMed

Sánchez, Enric; Betriu, Àngels; Arroyo, David; López, Carolina; Hernández, Marta; Rius, Ferran; Fernández, Elvira; Lecube, Albert

2017-01-01

Advanced glycation end-products (AGEs) are increased and predict mortality in patients with chronic kidney disease (CKD) who are undergoing hemodialysis, irrespective of the presence of type 2 diabetes. However, little information exits about the relationship between AGEs and subclinical atherosclerosis at the early stages of CKD. A case-control study was performed including 87 patients with mild-to-moderate stages of CKD (glomerular filtration rate from 89 to 30 ml/min/per 1.73m2) and 87 non-diabetic non-CKD subjects matched by age, gender, body mass index, and waist circumference. Skin autofluorescence (AF), a non-invasive assessment of AGEs, was measured. The presence of atheromatous disease in carotid and femoral arteries was evaluated using vascular ultrasound, and vascular age and SCORE risk were estimated. Patients with mild-to-moderate stages of CKD showed an increase in skin AF compared with control subjects (2.5±0.6 vs. 2.2±0.4 AU, p<0.001). A skin AF value >2.0 AU was accompanied by a 3-fold increased risk of detecting the presence of an atheromathous plaque (OR 3.0, 95% CI 1.4-6.5, p = 0.006). When vascular age was assessed through skin AF, subjects with CKD were almost 12 years older than control subjects (70.3±25.5 vs. 58.5±20.2 years, p = 0.001). Skin AF was negatively correlated with glomerular filtration rate (r = -0.354, p<0.001) and LDL-cholesterol (r = -0.269, p = 0.001), and positively correlated with age (r = 0.472, p<0.001), pulse pressure (r = 0.238, p = 0.002), and SCORE risk (r = 0.451, p<0.001). A stepwise multivariate regression analysis showed that age and glomerular filtration rate independently predicted skin AF (R2 = 0.289, p<0.001). Skin AF is elevated in patients with mild-to-moderate CKD compared with control subjects. This finding may be independently associated with the glomerular filtration rate and the presence of subclinical atheromatous disease. Therefore, the use of skin AF may help to accurately evaluate the real cardiovascular risk at the early stages of CKD.

Hyper-spectrum scanning laser optical tomography

NASA Astrophysics Data System (ADS)

Chen, Lingling; Li, Guiye; Li, Yingchao; Liu, Lina; Liu, Ang; Hu, Xuejuan; Ruan, Shuangchen

2018-02-01

We describe a quantitative fluorescence projection tomography technique which measures the three-dimensional fluorescence spectrum in biomedical samples with size up to several millimeters. This is achieved by acquiring a series of hyperspectral images, by using laser scanning scheme, at different projection angles. We demonstrate that this technique provide a quantitative measure of the fluorescence signal by comparing the spectrum and intensity profile of a fluorescent bead phantom and also demonstrate its application to differentiating the extrinsic label and the autofluorescence in a mouse embryo.

Fundus autofluorescence and retinal structure as determined by spectral domain optical coherence tomography, and retinal function in retinitis pigmentosa.

PubMed

Iriyama, Aya; Yanagi, Yasuo

2012-03-01

To investigate the association between fundus autofluorescence (FAF) and retinal structure and function in retinitis pigmentosa (RP). For image acquisition, HRA2 (Heidelberg Engineering) and 3D-OCT1000 (Topcon Corp.) were used. Based on FAF examination, 88 eyes of 44 RP patients were categorized into three types. The area within the hyperautofluorescent ring and the area of preserved retinal autofluorescence with FAF was calculated. The association between the pattern of FAF and the residual area of the junction between the inner and outer segments of the photoreceptors (IS/OS line), and the relationship between the area within hyperautofluorescent ring, the area of preserved retinal autofluorescence and the mean deviation (MD) of static perimetry were assessed. Twenty-four eyes were with preserved retinal autofluorescence without hyperautofluorescent ring, 54 eyes were with hyperautofluorescent ring and ten eyes were with abnormal foveal autofluorescence both in the fovea and the periphery of the 30° scan. In the first type, the IS/OS line was clearly detected. In the second type, the residual area of the partially distinct IS/OS line corresponded with the area within hyperautofluorescent ring with significant correlation between the area within hyperautofluorescent ring and the MD (R(2) = 0.705, p < 0.001); however, there was no correlation between the area of preserved retinal autofluorescence and the MD, or between the area of preserved retinal autofluorescence and the area within hyperautofluorescent ring. In the third type, the IS/OS line was completely absent. The residual IS/OS line can be found in the area inside the hyperautofluorescent ring and correlates with residual visual function.

Autofluorescence and spectral-domain optical coherence tomography of optic disk melanocytoma.

PubMed

Guerra, Ricardo Luz Leitão; Marback, Eduardo Ferrari; Silva, Igor Sandes Pessoa da; Maia Junior, Otacílio de Oliveira; Marback, Roberto Lorens

2014-01-01

The authors report fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (OCT) findings of two consecutive patients who presented with optic disk melanocytoma (ODM). A retrospective study was performed by reviewing medical records and ophthalmic imaging examinations. Optical coherence tomography findings were sloped and brightly reflective anterior tumor surface, adjacent retinal desorganization and abrupt posterior optical shadowing. Vitreous seeds were found in one patient. Fundus autofluorescence revealed outstanding hypoautofluorescence at the tumor area and isoautofluorescence at the remaining retina. Optical coherence tomography findings of the reported cases are consistent with those reported in the reviewed literature. Fundus autofluorescence has been used in the assessment of choroidal melanocytic tumors, but not yet in melanocytomas. We assume that this is the first report of these findings and believe that when its pattern has become clearly defined, fundus autofluorescence will be a useful tool to avoid misdiagnosis in suspicious cases and for follow-up.

Fundus autofluorescence and optical coherence tomography findings in thiamine responsive megaloblastic anemia.

PubMed

Ach, Thomas; Kardorff, Rüdiger; Rohrschneider, Klaus

2015-01-01

To report ophthalmologic fundus autofluorescence and spectral domain optical coherence tomography findings in a patient with thiamine responsive megaloblastic anemia (TRMA). A 13-year-old girl with genetically proven TRMA was ophthalmologically (visual acuity, funduscopy, perimetry, electroretinogram) followed up over >5 years. Fundus imaging also included autofluorescence and spectral domain optical coherence tomography. During a 5-year follow-up, visual acuity and visual field decreased, despite a special TRMA diet. Funduscopy revealed bull's eye appearance, whereas fundus autofluorescence showed central and peripheral hyperfluorescence and perifoveal hypofluorescence. Spectral domain optical coherence tomography revealed affected inner segment ellipsoid band and irregularities in the retinal pigment epithelium and choroidea. Autofluorescence and spectral domain optical coherence tomography findings in a patient with TRMA show retinitis pigmentosa-like retina, retinal pigment epithelium, and choroid alterations. These findings might progress even under special TRMA diet, indispensable to life. Ophthalmologist should consider TRMA in patients with deafness and ophthalmologic disorders.

Simple noninvasive measurement of skin autofluorescence.

PubMed

Meerwaldt, Robbert; Links, Thera; Graaff, Reindert; Thorpe, Suzannne R; Baynes, John W; Hartog, Jasper; Gans, Reinold; Smit, Andries

2005-06-01

Accumulation of advanced glycation end products (AGEs) is thought to play a role in the pathogenesis of chronic complications of diabetes mellitus and renal failure. Several studies indicate that AGE accumulation in tissue may reflect the cumulative effect of hyperglycemia and oxidative stress over many years. Simple quantitation of AGE accumulation in tissue could provide a tool for assessing the risk of long-term complications. Because several AGEs exhibit autofluorescence, we developed a noninvasive autofluorescence reader (AFR). Skin autofluorescence measured with the AFR correlates with collagen-linked fluorescence and specific skin AGE levels from skin biopsy samples. Furthermore, skin autofluorescence correlates with long-term glycemic control and renal function, and preliminary results show correlations with the presence of long-term complications in diabetes. The AFR may be useful as a clinical tool for rapid assessment of risk for AGE-related long-term complications in diabetes and in other conditions associated with AGE accumulation.

Combined autofluorescence and Raman spectroscopy method for skin tumor detection in visible and near infrared regions

NASA Astrophysics Data System (ADS)

Zakharov, V. P.; Bratchenko, I. A.; Artemyev, D. N.; Myakinin, O. O.; Khristoforova, Y. A.; Kozlov, S. V.; Moryatov, A. A.

2015-07-01

The combined application of Raman and autofluorescence spectroscopy in visible and near infrared regions for the analysis of malignant neoplasms of human skin was demonstrated. Ex vivo experiments were performed for 130 skin tissue samples: 28 malignant melanomas, 19 basal cell carcinomas, 15 benign tumors, 9 nevi and 59 normal tissues. Proposed method of Raman spectra analysis allows for malignant melanoma differentiating from other skin tissues with accuracy of 84% (sensitivity of 97%, specificity of 72%). Autofluorescence analysis in near infrared and visible regions helped us to increase the diagnostic accuracy by 5-10%. Registration of autofluorescence in near infrared region is realized in one optical unit with Raman spectroscopy. Thus, the proposed method of combined skin tissues study makes possible simultaneous large skin area study with autofluorescence spectra analysis and precise neoplasm type determination with Raman spectroscopy.

Classification of pollen species using autofluorescence image analysis.

PubMed

Mitsumoto, Kotaro; Yabusaki, Katsumi; Aoyagi, Hideki

2009-01-01

A new method to classify pollen species was developed by monitoring autofluorescence images of pollen grains. The pollens of nine species were selected, and their autofluorescence images were captured by a microscope equipped with a digital camera. The pollen size and the ratio of the blue to red pollen autofluorescence spectra (the B/R ratio) were calculated by image processing. The B/R ratios and pollen size varied among the species. Furthermore, the scatter-plot of pollen size versus the B/R ratio showed that pollen could be classified to the species level using both parameters. The pollen size and B/R ratio were confirmed by means of particle flow image analysis and the fluorescence spectra, respectively. These results suggest that a flow system capable of measuring both scattered light and the autofluorescence of particles could classify and count pollen grains in real time.

Imaging dental sections with polarization-resolved SHG and time-resolved autofluorescence

NASA Astrophysics Data System (ADS)

Chen, Jun Huang; Lin, Po-Yen; Hsu, Stephen C. Y.; Kao, Fu-Jen

2009-02-01

In this study, we are using two-photon (2-p) excited autofluorescence and second harmonic (SH) as imaging modalities to investigate dental sections that contains the enamel and the dentin. The use of near-infrared wavelengths for multiphoton excitation greatly facilitates the observation of these sections due to the hard tissue's larger index of refraction and highly scattering nature. Clear imaging can be achieved without feature altering preparation procedures of the samples. Specifically, we perform polarization resolving on SH and lifetime analysis on autofluorescence. Polarization resolved SH reflects the preferred orientation of collagen while very different autofluorescence lifetimes are observed from the dentin and the enamel. The origin of 2-p autofluorescence and SH signals are attributed to hydroxyapatite crystals and collagen fibrils, respectively. Hydroxyapatite is found to be present throughout the sections while collagen fibrils exist only in the dentin and dentinoenamel junctions.

Polarized near-infrared autofluorescence imaging combined with near-infrared diffuse reflectance imaging for improving colonic cancer detection.

PubMed

Shao, Xiaozhuo; Zheng, Wei; Huang, Zhiwei

2010-11-08

We evaluate the diagnostic feasibility of the integrated polarized near-infrared (NIR) autofluorescence (AF) and NIR diffuse reflectance (DR) imaging technique developed for colonic cancer detection. A total of 48 paired colonic tissue specimens (normal vs. cancer) were measured using the integrated NIR DR (850-1100 nm) and NIR AF imaging at the 785 nm laser excitation. The results showed that NIR AF intensities of cancer tissues are significantly lower than those of normal tissues (p<0.001, paired 2-sided Student's t-test, n=48). NIR AF imaging under polarization conditions gives a higher diagnostic accuracy (of ~92-94%) compared to non-polarized NIR AF imaging or NIR DR imaging. Further, the ratio imaging of NIR DR to NIR AF with polarization provides the best diagnostic accuracy (of ~96%) among the NIR AF and NIR DR imaging techniques. This work suggests that the integrated NIR AF/DR imaging under polarization condition has the potential to improve the early diagnosis and detection of malignant lesions in the colon.

Multispectral open-air intraoperative fluorescence imaging.

PubMed

Behrooz, Ali; Waterman, Peter; Vasquez, Kristine O; Meganck, Jeff; Peterson, Jeffrey D; Faqir, Ilias; Kempner, Joshua

2017-08-01

Intraoperative fluorescence imaging informs decisions regarding surgical margins by detecting and localizing signals from fluorescent reporters, labeling targets such as malignant tissues. This guidance reduces the likelihood of undetected malignant tissue remaining after resection, eliminating the need for additional treatment or surgery. The primary challenges in performing open-air intraoperative fluorescence imaging come from the weak intensity of the fluorescence signal in the presence of strong surgical and ambient illumination, and the auto-fluorescence of non-target components, such as tissue, especially in the visible spectral window (400-650 nm). In this work, a multispectral open-air fluorescence imaging system is presented for translational image-guided intraoperative applications, which overcomes these challenges. The system is capable of imaging weak fluorescence signals with nanomolar sensitivity in the presence of surgical illumination. This is done using synchronized fluorescence excitation and image acquisition with real-time background subtraction. Additionally, the system uses a liquid crystal tunable filter for acquisition of multispectral images that are used to spectrally unmix target fluorescence from non-target auto-fluorescence. Results are validated by preclinical studies on murine models and translational canine oncology models.

Demonstration of lipofuscin and Nissl bodies in crystal violet stained sections using a fluorescence technique or pyronin Y stain.

PubMed

Terr, L I

1986-09-01

This paper presents two simple, reliable methods for identification of lipofuscin and Nissl bodies in the same section. One method shows that lipofuscin stained with crystal violet retains its ability to fluoresce and can be observed under the fluorescence microscope after the stain has faded. Fading is accompanied by a gradual increase in the intensity of the fluorescence and is complete in about 5 min. Exciting illumination from this part of the spectrum also substantially fades staining of other autofluorescing tissue elements, such as lipids. Nonfluorescing structures, such as Nissl bodies, remain stained. By changing from transillumination with tungsten light to epifluorescent illumination and vice versa, both types of structures--Nissl bodies and lipofuscin--can be identified in the same section. The second technique uses pyronin Y for staining Nissl bodies in preparations previously stained with crystal violet. Nissl bodies are stained pink but lipofuscin remains violet. Lipofuscin in these sections also remains autofluorescent after the crystal violet stain has faded under violet or near-UV light.

Fundus autofluorescence and optical coherence tomography in relation to visual function in Usher syndrome type 1 and 2.

PubMed

Fakin, Ana; Jarc-Vidmar, Martina; Glavač, Damjan; Bonnet, Crystel; Petit, Christine; Hawlina, Marko

2012-12-15

Purpose of this study was to characterize retinal disease in Usher syndrome using fundus autofluorescence and optical coherence tomography. Study included 54 patients (26 male, 28 female) aged 7-70 years. There were 18 (33%) USH1 and 36 (67%) USH2 patients. 49/52 (94%) patients were found to carry at least one mutation in Usher genes. Ophthalmological examination included assessment of Snellen visual acuity, color vision with Ishihara tables, Goldmann visual fields (targets II/1-4 and V/4), microperimetry, fundus autofluorescence imaging and optical coherence tomography. Average age at disease onset (nyctalopia) was significantly lower in USH1 than USH2 patients (average 9 vs. 17 years, respectively; p<0.01); however no significant differences were found regarding type of autofluorescence patterns, frequency of foveal lesions and CME, rate of disease progression and age at legal blindness. All representative eyes had abnormal fundus autofluorescence of either hyperautofluorescent ring (55%), hyperautofluorescent foveal patch (35%) or foveal atrophy (10%). Disease duration of more than 30 years was associated with a high incidence of abnormal central fundus autofluorescence (patch or atrophy) and visual acuity loss. Copyright © 2012 Elsevier Ltd. All rights reserved.

The role of fundus autofluorescence in late-onset retinitis pigmentosa (LORP) diagnosis.

PubMed

Lee, Tamara J; Hwang, John C; Chen, Royce W S; Lima, Luiz H; Wang, Nan-Kai; Tosi, Joaquin; Freund, K Bailey; Yannuzzi, Lawrence A; Tsang, Stephen H

2014-09-01

To demonstrate the utility and characteristics of fundus autofluorescence in late-onset retinitis pigmentosa. Observational case series. Patients diagnosed with late-onset retinitis pigmentosa were identified retrospectively in an institutional setting. Twelve eyes of six patients were identified and medical records were reviewed. All patients presented with slowly progressive peripheral field loss and initial clinical examination revealed only subtle retinal changes. There was a notable lack of intraretinal pigment migration in all patients. Five out of six patients underwent magnetic resonance imaging of the brain to rule out intracranial processes and all were referred from another ophthalmologist for further evaluation. Fundus autofluorescence was ultimately employed in all patients and revealed more extensive retinal pathology than initially appreciated on clinical examination. Fundus autofluorescence directed the workup toward a retinal etiology in all cases and led to the eventual diagnosis of late-onset retinitis pigmentosa through electroretinogram testing. Fundus autofluorescence may be a more sensitive marker for retinal pathology than stereo fundus biomicroscopy alone in late-onset retinitis pigmentosa. Early use of fundus autofluorescence imaging in the evaluation of patients with subtle retinal lesions and complaints of peripheral field loss may be an effective strategy for timely and cost-efficient diagnosis.

Autofluorescence of pigmented skin lesions using a pulsed UV laser with synchronized detection: clinical results

NASA Astrophysics Data System (ADS)

Cheng, Haynes P. H.; Svenmarker, Pontus; Xie, Haiyan; Tidemand-Lichtenberg, Peter; Jensen, Ole B.; Bendsoe, Niels; Svanberg, Katarina; Petersen, Paul Michael; Pedersen, Christian; Andersson-Engels, Stefan; Andersen, Peter E.

2010-04-01

We report preliminary clinical results of autofluorescence imaging of malignant and benign skin lesions, using pulsed 355 nm laser excitation with synchronized detection. The novel synchronized detection system allows high signal-tonoise ratio to be achieved in the resulting autofluorescence signal, which may in turn produce high contrast images that improve diagnosis, even in the presence of ambient room light. The synchronized set-up utilizes a compact, diode pumped, pulsed UV laser at 355 nm which is coupled to a CCD camera and a liquid crystal tunable filter. The excitation and image capture is sampled at 5 kHz and the resulting autofluorescence is captured with the liquid crystal filter cycling through seven wavelengths between 420 nm and 580 nm. The clinical study targets pigmented skin lesions and evaluates the prospects of using autofluorescence as a possible means in differentiating malignant and benign skin tumors. Up to now, sixteen patients have participated in the clinical study. The autofluorescence images, averaged over the exposure time of one second, will be presented along with histopathological results. Initial survey of the images show good contrast and diagnostic results show promising agreement based on the histopathological results.

Instrumentation for the measurement of autofluorescence in human skin

NASA Astrophysics Data System (ADS)

Graaff, Reindert; Meerwaldt, Robbert; Lutgers, Helen L.; Baptist, Rene; de Jong, Ed D.; Zijp, Jaap R.; Links, Thera P.; Smit, Andries J.; Rakhorst, Gerhard

2005-04-01

A setup to measure skin autofluorescence was developed to assess accumulation of advanced glycation endproducts (AGE) in patients noninvasively. The method applies direct blacklight tube illumination of the skin of the lower arm, and spectrometry. The setup displays skin autofluorescence (AF) as a ratio of mean intensities detected from the skin between 420-600 nm and 300-420 nm, respectively. In an early clinical application in 46 and control subjects matched for age and gender, AF was significantly increased in the patients (p = 0.015), and highly correlated with skin AGE's that were determined from skin biopsies in both groups. A large follow-up study on type 2 diabetes mellitus, ongoing since 2001 with more than 1000 subjects, aims to assess the value of the instrument in predicting chronic complications of diabetes. At baseline, a relation with age, glycemic status and with complications present was found. In a study in patients with end stage renal disease on dialysis AF was a strong and independent predictor of total and cardiovascular mortality. A commercial version of this AGE-reader is now under development and becomes available early 2005 (DiagnOptics B.V., Groningen, The Netherlands). One of the remaining questions, that will be answered by measuring so-called Exciation-Emission Matrices (EEM's) of the skin tissue in vivo, is whether a more selective choice of wavelengths is more strongly related to clinical characteristics. An experimental instrument to measure these EEM's was, therefore, developed as well. Clinical measurements are underway of EEM's in patient groups with diabetes mellitus and in healthy volunteers.

Autofluorescence spectroscopy for multimodal tissues characterization in colitis-associated cancer murine model

NASA Astrophysics Data System (ADS)

Dorez, Hugo; Sablong, Raphaël.; Canaple, Laurence; Saint-Jalmes, Hervé; Gaillard, Sophie; Moussata, Driffa; Beuf, Olivier

2015-07-01

The purpose of this research project is to assess mice colon wall, using three optical modalities (conventional endoscopy, confocal endomicroscopy and optical spectroscopy) and endoluminal MRI. The study is done in the context of inflammatory bowel disease and colorectal cancer that represent 13% of new cases of cancer, every year in western countries. An optical spectroscopic bench (autofluorescence and reflectance) was developed with a flexible fiber probe. This latter has been combined with a mini multi-purpose rigid endoscope and a confocal endomicroscope. The optical modalities were first used in vivo on SWISS mice. Then, a specific optical a phantom (containing two layers of distinct fluorophores) was developed in order to evaluate our two-channel spectroscopic probe as a basic depth-sensitive measurement tool. The preliminary results show the feasibility to combine such modalities in the same in vivo protocol. Conventional endoscopy is useful to depict inflammation along colon wall. Confocal endomicroscopy provides high-contrasted images of microvascularization. Measured optical spectra both depend on biochemical tissue content and layered structure of the medium. The light collected from one channel is not similar to the other, in terms of intensity and spectroscopic profile as the interaction with the medium observed volume is different. A comparative analysis of the spectra based on our in vitro model exhibits a strong correlation between simple index extracted from spectral data and two main phantom characteristics (fluorophore concentrations and superficial layer thickness). This work suggests that this technique could contribute to assess tissues alterations through autofluorescence spectroscopic measurement under endoscopy.

MRT letter: Auto-fluorescence by human alveolar macrophages after in vitro exposure to air pollution particles.

PubMed

Ghio, Andrew J; Sangani, Rahul G; Brighton, Luisa E; Carson, John L

2010-06-01

Macrophages from smokers demonstrate an increased auto-fluorescence. Similarly, auto-fluorescence follows in vitro exposure of macrophages to cigarette smoke condensate (i.e., the particulate fraction of cigarette smoke). The composition of particles in cigarette smoke can be comparable to air pollution particles. We tested the postulate that macrophages exposed to air pollution particles could demonstrate auto-fluorescence. Healthy nonsmoking and healthy smoking volunteers (both 18-40 years of age) underwent fiberoptic bronchoscopy with bronchoalveolar lavage and alveolar macrophages isolated. Macrophages were incubated at 37 degrees C in 5% CO(2) with either PBS or 100 microg/mL particle for both 1 and 24 h. Particles included a residual oil fly ash, Mt. St. Helens volcanic ash, and ambient air particles collected from St. Louis, Missouri and Salt Lake City, Utah. At the end of incubation, 50 microL of the cell suspension was cytocentrifuged and examined at modes for viewing fluorescein isothiocyanate (FITC) and rhodamine fluorescence. Both emission source air pollution particles demonstrated FITC and rhodamine auto-fluorescence at 1 and 24 h, but the signal following incubation of the macrophages with oil fly ash appeared greater. Similarly, the ambient particles were associated with auto-fluorescence by the alveolar macrophages and this appeared to be dose-dependent. We conclude that exposure of macrophages to air pollution particles can be associated with auto-fluorescence in the FITC and rhodamine modes. c) 2009 Wiley-Liss, Inc

Rapid and simple method of photobleaching to reduce background autofluorescence in lung tissue sections.

PubMed

Kumar, B Santhosh; Sandhyamani, S; Nazeer, Shaiju S; Jayasree, R S

2015-02-01

Autofluorescence exhibited by tissues often interferes with immunofluorescence. Using imaging and spectral analysis, we observed remarkable reduction of autofluorescence of formalin fixed paraffin embedded tissues irradiated with light prior to incubation with immunofluorescent dyes. The technique of photobleaching offers significant improvement in the quality and specificity of immunofluorescence. This has the potential for better techniques for disease diagnosis.

The use of native fluorescence analysis of synovial fluid in the diagnosis of medial compartment disease in medium- and large-breed dogs.

PubMed

Bilská, Kamila; Šteffeková, Zuzana; Birková, Anna; Mareková, Mária; Ledecký, Valent; Hluchý, Marián; Kisková, Terézia

2016-05-01

We assumed that proteins are most likely responsible for synovial fluid fluorescence and that changes detected in fluorescence intensity are most likely the result of changes in the concentration of fluorescent proteins. Synchronous fluorescent matrices from synovial fluid samples were measured in the excitation wavelength range of 200-350 nm using a luminescence spectrophotometer. The synchronous matrix of synovial fluid consists of 2 dominant fluorescent centers (F1 and F2) in the ultraviolet region. The fluorescence intensities of both centers were significantly higher in pathological samples, with p = 0.001 (a 59% increase of the median value) for the F1 center and p = 0.002 (a 52% increase of the median value) for the F2 center. Receiver operating characteristic analysis confirmed that synovial fluid autofluorescence is a significant predictor of medial compartment disease in dogs, with the area under the curve at 0.776 (F1) and 0.778 (F2). We did not detect any differences in the autofluorescence of synovial fluid between male and female, or any breed-based changes. No position changes of fluorescent centers were recorded in the synovial fluid in diseased dogs compared with healthy dogs. The synovial fluid metabolic fingerprint of canine patients with medial compartment disease differed from that of healthy dogs. Our study demonstrated the feasibility of synovial fluid fingerprinting to identify disease-specific profiles of synovial fluid metabolites. © 2016 The Author(s).

Imaging Lenticular Autofluorescence in Older Subjects.

PubMed

Charng, Jason; Tan, Rose; Luu, Chi D; Sadigh, Sam; Stambolian, Dwight; Guymer, Robyn H; Jacobson, Samuel G; Cideciyan, Artur V

2017-10-01

To evaluate whether a practical method of imaging lenticular autofluorescence (AF) can provide an individualized measure correlated with age-related lens yellowing in older subjects undergoing tests involving shorter wavelength lights. Lenticular AF was imaged with 488-nm excitation using a confocal scanning laser ophthalmoscope (cSLO) routinely used for retinal AF imaging. There were 75 older subjects (ages 47-87) at two sites; a small cohort of younger subjects served as controls. At one site, the cSLO was equipped with an internal reference to allow quantitative AF measurements; at the other site, reduced-illuminance AF imaging (RAFI) was used. In a subset of subjects, lens density index was independently estimated from dark-adapted spectral sensitivities performed psychophysically. Lenticular AF intensity was significantly higher in the older eyes than the younger cohort when measured with the internal reference (59.2 ± 15.4 vs. 134.4 ± 31.7 gray levels; P < 0.05) as well as when recorded with RAFI without the internal reference (10.9 ± 1.5 vs. 26.1 ± 5.7 gray levels; P < 0.05). Lenticular AF was positively correlated with age; however, there could also be large differences between individuals of similar age. Lenticular AF intensity correlated well with lens density indices estimated from psychophysical measures. Lenticular AF measured with a retinal cSLO can provide a practical and individualized measure of lens yellowing, and may be a good candidate to distinguish between preretinal and retinal deficits involving short-wavelength lights in older eyes.

In vivo imaging of retinal pigment epithelium cells in age related macular degeneration

PubMed Central

Rossi, Ethan A.; Rangel-Fonseca, Piero; Parkins, Keith; Fischer, William; Latchney, Lisa R.; Folwell, Margaret A.; Williams, David R.; Dubra, Alfredo; Chung, Mina M.

2013-01-01

Morgan and colleagues demonstrated that the RPE cell mosaic can be resolved in the living human eye non-invasively by imaging the short-wavelength autofluorescence using an adaptive optics (AO) ophthalmoscope. This method, based on the assumption that all subjects have the same longitudinal chromatic aberration (LCA) correction, has proved difficult to use in diseased eyes, and in particular those affected by age-related macular degeneration (AMD). In this work, we improve Morgan’s method by accounting for chromatic aberration variations by optimizing the confocal aperture axial and transverse placement through an automated iterative maximization of image intensity. The increase in image intensity after algorithmic aperture placement varied depending upon patient and aperture position prior to optimization but increases as large as a factor of 10 were observed. When using a confocal aperture of 3.4 Airy disks in diameter, images were obtained using retinal radiant exposures of less than 2.44 J/cm2, which is ~22 times below the current ANSI maximum permissible exposure. RPE cell morphologies that were strikingly similar to those seen in postmortem histological studies were observed in AMD eyes, even in areas where the pattern of fluorescence appeared normal in commercial fundus autofluorescence (FAF) images. This new method can be used to study RPE morphology in AMD and other diseases, providing a powerful tool for understanding disease pathogenesis and progression, and offering a new means to assess the efficacy of treatments designed to restore RPE health. PMID:24298413

A case of rhabdomyolysis after kidney transplantation successfully managed with intensive continuous dialysis.

PubMed

Shahbazov, Rauf; Fox, Michael; Alejo, Jennifer L; Anjum, Malik A; Azari, Feredun; Doyle, Alden; Agarwal, Avinash; Brayman, Kenneth L

2018-04-01

Rhabdomyolysis is characterized by muscle cell death which can result in acute kidney injury from pigment nephropathy. We present a patient who developed rhabdomyolysis immediately after deceased donor kidney transplantation surgery and was managed with continuous renal replacement therapy that resulted in successful salvage of the kidney allograft. Patients who develop acute kidney failure requiring renal replacement therapy generally have a poor prognosis. It is worth noting that while continuous veno-venous hemofiltration (CVVHF) offers greater volume support and continuous clearance compared to hemodialysis (HD), recent studies have demonstrated no clinically significant improvement in clinical outcome between the two. Perhaps CVVHF is a better modality compared to HD in this setting to prevent further insult from pigment nephropathy to an allograft. A combination of early diagnosis and intensive continuous renal replacement therapy can be used for allograft salvage in a patient with rhabdomyolysis in the immediate post-kidney transplant period.

Management of Chronic Kidney Disease Patients in the Intensive Care Unit: Mixing Acute and Chronic Illness.

PubMed

De Rosa, Silvia; Samoni, Sara; Villa, Gianluca; Ronco, Claudio

2017-01-01

Patients with chronic kidney disease (CKD) are at high risk for developing critical illness and for admission to intensive care units (ICU). 'Critically ill CKD patients' frequently develop an acute worsening of renal function (i.e. acute-on-chronic, AoC) that contributes to long-term kidney dysfunction, potentially leading to end-stage kidney disease (ESKD). An integrated multidisciplinary effort is thus necessary to adequately manage the multi-organ damage of those kidney patients and contemporaneously reduce the progression of kidney dysfunction when they are critically ill. The aim of this review is to describe (1) the pathophysiological mechanisms underlying the development of AoC kidney dysfunction and its role in the progression toward ESKD; (2) the most common clinical presentations of critical illness among CKD/ESKD patients; and (3) the continuum of care for CKD/ESKD patients from maintenance hemodialysis/peritoneal dialysis to acute renal replacement therapy performed in ICU and, vice-versa, for AoC patients who develop ESKD. © 2017 S. Karger AG, Basel.

Autofluorescence-Free Live-Cell Imaging Using Terbium Nanoparticles.

PubMed

Cardoso Dos Santos, M; Goetz, J; Bartenlian, H; Wong, K-L; Charbonnière, L J; Hildebrandt, N

2018-04-18

Fluorescent nanoparticles (NPs) have become irreplaceable tools for advanced cellular and subcellular imaging. While very bright NPs require excitation with UV or visible light, which can create strong autofluorescence of biological components, NIR-excitable NPs without autofluorescence issues exhibit much lower brightness. Here, we show the application of a new type of surface-photosensitized terbium NPs (Tb-NPs) for autofluorescence-free intracellular imaging in live HeLa cells. The combination of exceptionally high brightness, high photostability, and long photoluminecence (PL) lifetimes for highly efficient suppression of the short-lived autofluorescence allowed for time-gated PL imaging of intracellular vesicles over 72 h without toxicity and at extremely low Tb-NP concentrations down to 12 pM. Detection of highly resolved long-lifetime (ms) PL decay curves from small (∼10 μm 2 ) areas within single cells within a few seconds emphasized the unprecedented photophysical properties of Tb-NPs for live-cell imaging that extend well beyond currently available nanometric imaging agents.

Development of Low-Cost Instrumentation for Single Point Autofluorescence Lifetime Measurements.

PubMed

Lagarto, João; Hares, Jonathan D; Dunsby, Christopher; French, Paul M W

2017-09-01

Autofluorescence lifetime measurements, which can provide label-free readouts in biological tissues, contrasting e.g. different types and states of tissue matrix components and different cellular metabolites, may have significant clinical potential for diagnosis and to provide surgical guidance. However, the cost of the instrumentation typically used currently presents a barrier to wider implementation. We describe a low-cost single point time-resolved autofluorescence instrument, exploiting modulated laser diodes for excitation and FPGA-based circuitry for detection, together with a custom constant fraction discriminator. Its temporal accuracy is compared against a "gold-standard" instrument incorporating commercial TCSPC circuitry by resolving the fluorescence decays of reference fluorophores presenting single and double exponential decay profiles. To illustrate the potential to read out intrinsic contrast in tissue, we present preliminary measurements of autofluorescence lifetime measurements of biological tissues ex vivo. We believe that the lower cost of this instrument could enhance the potential of autofluorescence lifetime metrology for clinical deployment and commercial development.

Study of lens autofluorescence by fluorophotometry in pregnant patients with diabetes.

PubMed

Beneyto, P; Alonso, I; Pérez, T M; López, L; Fonseca, A

1996-05-01

Lens autofluorescence originates from an accumulation of fluorescent substances such as the tryptophan-derived residues and glycosylated protein aggregations, which are associated with the process of cataractogenesis and lens aging. The purpose of this investigation is to determine whether pregnancy alters the typical constituents of the lens autofluorescence in patients with diabetes and, if so, to what degree this may occur. Lens autofluorescence was studied with fluorophotometry in 127 eyes of 72 individuals: 23 control subjects, 6 healthy pregnant women, 21 patients with diabetes, and 44 pregnant patients with diabetes. The autofluorescence values were 311 +/- 130 ng/ml, 253 +/- 40 ng/ml, 378 +/- 110 ng/ml, and 562 +/- 164 Eq ng/ml (Eq ng/ml = Ng/ml equivalent fluorescein) in the four groups, respectively. The difference between the nonpregnant and pregnant patients with diabetes was significant (P < 0.001). These results suggest that there is an important deterioration in the metabolic state of the lens during gestation in patients with diabetes, as is the case for diabetic retinopathy.

Fundus autofluorescence in chronic essential hypertension.

PubMed

Ramezani, Alireza; Saberian, Peyman; Soheilian, Masoud; Parsa, Saeed Alipour; Kamali, Homayoun Koohi; Entezari, Morteza; Shahbazi, Mohammad-Mehdi; Yaseri, Mehdi

2014-01-01

To evaluate fundus autofluorescence (FAF) changes in patients with chronic essential hypertension (HTN). In this case-control study, 35 eyes of 35 patients with chronic essential HTN (lasting >5 years) and 31 eyes of 31 volunteers without history of HTN were included. FAF pictures were taken from right eyes of all cases with the Heidelberg retina angiography and then were assessed by two masked retinal specialists. In total, FAF images including 35 images of hypertensive patients and 31 pictures of volunteers, three apparently abnormal patterns were detected. A ring of hyper-autofluorescence in the central macula (doughnut-shaped) was observed in 9 (25.7%) eyes of the hypertensive group but only in 2 (6.5%) eyes of the control group. This difference was statistically significant (P = 0.036) between two groups. Hypo- and/or hyper-autofluorescence patches outside the fovea were the other sign found more in the hypertensive group (22.9%) than in the control group (6.5%); however, the difference was not statistically significant (P = 0.089). The third feature was hypo-autofluorescence around the disk noticed in 11 (31.4%) eyes of hypertensive patients compared to 8 (25.8%) eyes of the controls (P = 0.615). A ring of hyper-autofluorescence in the central macula forming a doughnut-shaped feature may be a FAF sign in patients with chronic essential HTN.

The Role of Fundus Autofluorescence in Late-Onset Retinitis Pigmentosa (LORP) Diagnosis

PubMed Central

Lee, Tamara J.; Hwang, John C.; Chen, Royce W. S.; Lima, Luiz H.; Wang, Nan-Kai; Tosi, Joaquin; Freund, K. Bailey; Yannuzzi, Lawrence A.; Tsang, Stephen H.

2015-01-01

Purpose To demonstrate the utility and characteristics of fundus autofluorescence in late-onset retinitis pigmentosa. Methods Observational case series. Patients diagnosed with late-onset retinitis pigmentosa were identified retrospectively in an institutional setting. Twelve eyes of six patients were identified and medical records were reviewed. Results All patients presented with slowly progressive peripheral field loss and initial clinical examination revealed only subtle retinal changes. There was a notable lack of intraretinal pigment migration in all patients. Five out of six patients underwent magnetic resonance imaging of the brain to rule out intracranial processes and all were referred from another ophthalmologist for further evaluation. Fundus autofluorescence was ultimately employed in all patients and revealed more extensive retinal pathology than initially appreciated on clinical examination. Fundus autofluorescence directed the workup toward a retinal etiology in all cases and led to the eventual diagnosis of late-onset retinitis pigmentosa through electroretinogram testing. Conclusion Fundus autofluorescence may be a more sensitive marker for retinal pathology than stereo fundus biomicroscopy alone in late-onset retinitis pigmentosa. Early use of fundus autofluorescence imaging in the evaluation of patients with subtle retinal lesions and complaints of peripheral field loss may be an effective strategy for timely and cost-efficient diagnosis. PMID:23899229

Dual-emissive quantum dots for multispectral intraoperative fluorescence imaging.

PubMed

Chin, Patrick T K; Buckle, Tessa; Aguirre de Miguel, Arantxa; Meskers, Stefan C J; Janssen, René A J; van Leeuwen, Fijs W B

2010-09-01

Fluorescence molecular imaging is rapidly increasing its popularity in image guided surgery applications. To help develop its full surgical potential it remains a challenge to generate dual-emissive imaging agents that allow for combined visible assessment and sensitive camera based imaging. To this end, we now describe multispectral InP/ZnS quantum dots (QDs) that exhibit a bright visible green/yellow exciton emission combined with a long-lived far red defect emission. The intensity of the latter emission was enhanced by X-ray irradiation and allows for: 1) inverted QD density dependent defect emission intensity, showing improved efficacies at lower QD densities, and 2) detection without direct illumination and interference from autofluorescence. Copyright 2010 Elsevier Ltd. All rights reserved.

Multimodal imaging of the disease progression of birdshot chorioretinopathy.

PubMed

Teussink, Michel M; Huis In Het Veld, Paulien I; de Vries, Lieuwe A M; Hoyng, Carel B; Klevering, B Jeroen; Theelen, Thomas

2016-12-01

To study outer retinal deterioration in relation to clinical disease activity in patients with birdshot chorioretinopathy using fundus autofluorescence and spectral-domain optical coherence tomography (OCT). A single-centre retrospective cohort study was carried out on 42 eyes of 21 patients with birdshot disease, using a multimodal imaging approach including fundus autofluorescence, OCT, fluorescein angiography and indocyanine green angiography in combination with a patient chart review. The patients' overall clinical activity of retinal vasculitis during the follow-up period was determined by periods of clinical activity as indicated by fluorescein angiography and associated treatment decisions. Image analysis was performed to examine the spatial correspondence between autofluorescence changes and disruption of the photoreceptor inner segment ellipsoid zone on OCT. Three common types of outer retinal lesions were observed in fovea-centred images of 43% of patients: circular patches of chorioretinal atrophy, ellipsoid zone disruption on OCT, and outer retinal atrophy on autofluorescence and OCT. There was good spatial correspondence between ellipsoid zone disruption and areas of diffuse hyper-autofluorescence outside the fovea. Interestingly, the ellipsoid zone disruption recovered in four out of seven patients upon intensified therapeutic immunosuppression. Most patients only developed peripapillary atrophy and occasional perivascular hypo-autofluorescence. A multimodal imaging approach with autofluorescence imaging and OCT may help to detect ellipsoid zone disruption in the central retina of patients with birdshot disease. Our results suggest that ellipsoid zone disruption may be related to both the activity and duration of retinal vasculitis, and could help to determine therapeutic success in birdshot disease. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Advanced glycation end products, carotid atherosclerosis, and circulating endothelial progenitor cells in patients with end-stage renal disease.

PubMed

Ueno, Hiroki; Koyama, Hidenori; Fukumoto, Shinya; Tanaka, Shinji; Shoji, Takuhito; Shoji, Tetsuo; Emoto, Masanori; Tahara, Hideki; Inaba, Masaaki; Kakiya, Ryusuke; Tabata, Tsutomu; Miyata, Toshio; Nishizawa, Yoshiki

2011-04-01

Numbers of endothelial progenitor cells (EPCs) have been shown to be decreased in subjects with end-stage renal disease (ESRD), the mechanism of which remained poorly understood. In this study, mutual association among circulating EPC levels, carotid atherosclerosis, serum pentosidine, and skin autofluorescence, a recently established noninvasive measure of advanced glycation end products accumulation, was examined in 212 ESRD subjects undergoing hemodialysis. Numbers of circulating EPCs were measured as CD34+ CD133+ CD45(low) VEGFR2+ cells and progenitor cells as CD34+ CD133+ CD45(low) fraction by flow cytometry. Skin autofluorescence was assessed by the autofluorescence reader; and serum pentosidine, by enzyme-linked immunosorbent assay. Carotid atherosclerosis was determined as intimal-medial thickness (IMT) measured by ultrasound. Circulating EPCs were significantly and inversely correlated with skin autofluorescence in ESRD subjects (R = -0.216, P = .002), but not with serum pentosidine (R = -0.079, P = .25). Circulating EPCs tended to be inversely associated with IMT (R = -0.125, P = .069). Intimal-medial thickness was also tended to be correlated positively with skin autofluorescence (R = 0.133, P = .054) and significantly with serum pentosidine (R = 0.159, P = .019). Stepwise multiple regression analyses reveal that skin autofluorescence, but not serum pentosidine and IMT, was independently associated with low circulating EPCs. Of note, skin autofluorescence was also inversely and independently associated with circulating progenitor cells. Thus, tissue accumulated, but not circulating, advanced glycation end products may be a determinant of a decrease in circulating EPCs in ESRD subjects. Copyright © 2011 Elsevier Inc. All rights reserved.

Centrifugal Expansion of Fundus Autofluorescence Patterns in Stargardt Disease Over Time

PubMed Central

Cukras, Catherine A.; Wong, Wai T.; Caruso, Rafael; Cunningham, Denise; Zein, Wadih; Sieving, Paul

2012-01-01

Objective Changing lipofuscin and melanin content in RPE cells has been hypothesized to contribute to Stargardt disease pathogenesis. Longitudinal study of autofluorescence in Stargardt disease which reflect changing fluorophore compositions can reveal aspects of disease progression not previously evident. Method We examined the temporal-spatial patterns of fundus autofluorescence with excitation at both 488 nm (standard fundus autofluorescence, FAF) and 795nm (near infrared autofluorescence, NIA) in a longitudinal case series involving 8 eyes of 4 patients (range of follow-up = 11 to 57 months; mean = 39 months). Image processing was performed to analyze spatial and temporal cross-modality associations. Results Longitudinal FAF imaging of fleck lesions revealed hyperautofluorescent lesions that extended in a centrifugal direction from the fovea with time. Patterns of spread were non-random and followed a radial path that leaves behind a trail of diminishing autofluorescence. Longitudinal NIA imaging also demonstrated centrifugal lesion spread, but with fewer hyperautofluorescent lesions, suggestive of more transient hyperautofluorescence and more rapid decay at longer wavelengths. FAF and NIA abnormalities were spatially correlated to each other, and together reflect systematic progressions in fleck distribution and fluorophore composition occurring during the natural history of the disease. Conclusion Stargardt disease fleck lesions do not evolve randomly in location but instead follow consistent patterns of radial expansion and a systematic decay of autofluorescence that reflect changing lipofuscin and melanin compositions in RPE cells. These progressive foveal-to-peripheral changes are helpful in elucidating molecular and cellular mechanisms underlying Stargardt disease and may constitute potential outcome measures in clinical trials. PMID:21987580

Feasibility for detection of autofluorescent signatures in rat organs using a novel excitation-scanning hyperspectral imaging system

NASA Astrophysics Data System (ADS)

Favreau, Peter F.; Deal, Joshua A.; Weber, David S.; Rich, Thomas C.; Leavesley, Silas J.

2016-04-01

The natural fluorescence (autofluorescence) of tissues has been noted as a biomarker for cancer for several decades. Autofluorescence contrast between tumors and healthy tissues has been of significant interest in endoscopy, leading to development of autofluorescence endoscopes capable of visualizing 2-3 fluorescence emission wavelengths to achieve maximal contrast. However, tumor detection with autofluorescence endoscopes is hindered by low fluorescence signal and limited quantitative information, resulting in prolonged endoscopic procedures, prohibitive acquisition times, and reduced specificity of detection. Our lab has designed a novel excitation-scanning hyperspectral imaging system with high fluorescence signal detection, low acquisition time, and enhanced spectral discrimination. In this study, we surveyed a comprehensive set of excised tissues to assess the feasibility of detecting tissue-specific pathologies using excitation-scanning. Fresh, untreated tissue specimens were imaged from 360 to 550 nm on an inverted fluorescence microscope equipped with a set of thin-film tunable filters (Semrock, A Unit of IDEX). Images were subdivided into training and test sets. Automated endmember extraction (ENVI 5.1, Exelis) with PCA identified endmembers within training images of autofluorescence. A spectral library was created from 9 endmembers. The library was used for identification of endmembers in test images. Our results suggest (1) spectral differentiation of multiple tissue types is possible using excitation scanning; (2) shared spectra between tissue types; and (3) the ability to identify unique morphological features in disparate tissues from shared autofluorescent components. Future work will focus on isolating specific molecular signatures present in tissue spectra, and elucidating the contribution of these signatures in pathologies.

Ultra-wide-field fundus autofluorescence in multiple evanescent white dot syndrome.

PubMed

Hashimoto, Hideaki; Kishi, Shoji

2015-04-01

To observe the progression of affected lesions using ultra-wide-field fundus autofluorescence (FAF) in multiple evanescent white dot syndrome. Retrospective, observational case series. setting: Institutional. 14 eyes of 13 patients (mean age, 35.8 years) with acute disease unilaterally. Patients underwent ultra-wide-field FAF, spectral-domain optical coherence tomography (SD OCT), multifocal electroretinography (mfERG), and Goldmann or automated perimetry; the best-corrected visual acuity (BCVA) and refractive error were measured. Ability of ultra-wide-field FAF to detect lesions with greater sensitivity compared with color fundus photography. Ultra-wide-field FAF imaging enabled improved visualization of the affected lesions and showed that the core lesion was in the posterior fundus involving the peripapillary retina and posterior pole and surrounded by hyper-autofluorescent spots outside the vascular arcade. The posterior lesions expanded rapidly and peripheral spots spread farther peripherally and reached a maximal extent during the acute stage. During follow-up, the peripheral hyper-autofluorescent spots resolved and then hyper-autofluorescence of the posterior fundus gradually faded. SD OCT showed diffuse disruption of the photoreceptor inner segment/outer segment junction (IS/OS) in the posterior fundus during the acute stage. The correlation between the IS/OS abnormality and hyper-autofluorescent areas was unclear. The disrupted IS/OS was restored with normalization of the FAF. Ultra-wide-field FAF showed that the lesions arise from the peripapillary retina and the posterior pole and spread peripherally in a centrifugal manner during the acute stage. The hyper-autofluorescent spots faded from the periphery in a centripetal manner. Copyright © 2015 Elsevier Inc. All rights reserved.

Autofluorescence lifetime imaging during transoral robotic surgery: a clinical validation study of tumor detection (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lagarto, João. L.; Phipps, Jennifer E.; Unger, Jakob; Faller, Leta M.; Gorpas, Dimitris; Ma, Dinglong M.; Bec, Julien; Moore, Michael G.; Bewley, Arnaud F.; Yankelevich, Diego R.; Sorger, Jonathan M.; Farwell, Gregory D.; Marcu, Laura

2017-02-01

Autofluorescence lifetime spectroscopy is a promising non-invasive label-free tool for characterization of biological tissues and shows potential to report structural and biochemical alterations in tissue owing to pathological transformations. In particular, when combined with fiber-optic based instruments, autofluorescence lifetime measurements can enhance intraoperative diagnosis and provide guidance in surgical procedures. We investigate the potential of a fiber-optic based multi-spectral time-resolved fluorescence spectroscopy instrument to characterize the autofluorescence fingerprint associated with histologic, morphologic and metabolic changes in tissue that can provide real-time contrast between healthy and tumor regions in vivo and guide clinicians during resection of diseased areas during transoral robotic surgery. To provide immediate feedback to the surgeons, we employ tracking of an aiming beam that co-registers our point measurements with the robot camera images and allows visualization of the surgical area augmented with autofluorescence lifetime data in the surgeon's console in real-time. For each patient, autofluorescence lifetime measurements were acquired from normal, diseased and surgically altered tissue, both in vivo (pre- and post-resection) and ex vivo. Initial results indicate tumor and normal regions can be distinguished based on changes in lifetime parameters measured in vivo, when the tumor is located superficially. In particular, results show that autofluorescence lifetime of tumor is shorter than that of normal tissue (p < 0.05, n = 3). If clinical diagnostic efficacy is demonstrated throughout this on-going study, we believe that this method has the potential to become a valuable tool for real-time intraoperative diagnosis and guidance during transoral robot assisted cancer removal interventions.

Stressful life events and acute kidney injury in intensive and semi-intensive care unities.

PubMed

Diniz, Denise Para; Marques, Daniella Aparecida; Blay, Sérgio Luis; Schor, Nestor

2012-03-01

Several studies point out that pathophysiological changes related to stress may influence renal function and are associated with disease onset and evolution. However, we have not found any studies about the influence of stress on renal function and acute kidney injury. To evaluate the association between stressful life events and acute kidney injury diagnosis, specifying the most stressful classes of events for these patients in the past 12 months. Case-control study. The study was carried out at Hospital São Paulo, in Universidade Federal de São Paulo and at Hospital dos Servidores do Estado de São Paulo, in Brazil. Patients with acute kidney injury and no chronic disease, admitted to the intensive or semi-intensive care units were included. Controls included patients in the same intensive care units with other acute diseases, except for the acute kidney injury, and also with no chronic disease. Out of the 579 patients initially identified, 475 answered to the Social Readjustment Rating Scale (SRRS) questionnaire and 398 were paired by age and gender (199 cases and 199 controls). The rate of stressful life events was statistically similar between cases and controls. The logistic regression analysis to detect associated effects of the independent variables to the stressful events showed that: increasing age and economic classes A and B in one of the hospitals (Hospital São Paulo - UNIFESP) increased the chance of a stressful life event (SLE). This study did not show association between the Acute Kidney Injury Group with a higher frequency of stressful life events, but that old age, higher income, and type of clinical center were associated.

Identification of endogenous fluorophores in the photoreceptors using autofluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Zhao, Lingling; Qu, Junle; Niu, Hanben

2007-11-01

In this paper, we present our investigation on the identification of endogenous fluorophores in photoreceptors using autofluorescence spectroscopy, which is performed with an inverted laser scanning confocal microscope equipped with an Argon ion laser and a GreNe laser. In our experiments, individual cones and rods are clearly resolved even in freshly prepared retina samples, without slicing or labeling. The experiment results show that autofluorescence spectrum of the photoreceptors has three peaks approximately at 525nm, 585nm and 665nm. Furthermore, the brightest autofluorescence originates from the photoreceptor outer segments. We can, therefore, come to a conclusion that the peaks at 525nm, 585nm are corresponding to FAD and A2-PE, respectively, which are distributed in the photoreceptor outer segments.

Intensive systolic blood pressure control and incident chronic kidney disease in people with and without diabetes mellitus: secondary analyses of two randomised controlled trials.

PubMed

Beddhu, Srinivasan; Greene, Tom; Boucher, Robert; Cushman, William C; Wei, Guo; Stoddard, Gregory; Ix, Joachim H; Chonchol, Michel; Kramer, Holly; Cheung, Alfred K; Kimmel, Paul L; Whelton, Paul K; Chertow, Glenn M

2018-07-01

Guidelines, including the 2017 American College of Cardiology and American Heart Association blood pressure guideline, recommend tighter control of systolic blood pressure in people with type 2 diabetes. However, it is unclear whether intensive lowering of systolic blood pressure increases the incidence of chronic kidney disease in this population. We aimed to compare the effects of intensive systolic blood pressure control on incident chronic kidney disease in people with and without type 2 diabetes. The Systolic Blood Pressure Intervention Trial (SPRINT) tested the effects of a systolic blood pressure goal of less than 120 mm Hg (intensive intervention) versus a goal of less than 140 mm Hg (standard intervention) in people without diabetes. The Action to Control Cardiovascular Risk in Diabetes (ACCORD) blood pressure trial tested a similar systolic blood pressure intervention in people with type 2 diabetes. Our study is a secondary analysis of limited access datasets from SPRINT and the ACCORD trial obtained from the National Institutes of Health. In participants without chronic kidney disease at baseline (n=4311 in the ACCORD trial; n=6715 in SPRINT), we related systolic blood pressure interventions (intensive vs standard) to incident chronic kidney disease (defined as >30% decrease in estimated glomerular filtration rate [eGFR] to <60 mL/min per 1·73 m 2 ). These trials are registered with ClinicalTrials.gov, numbers NCT01206062 (SPRINT) and NCT00000620 (ACCORD trial). The average difference in systolic blood pressure between intensive and standard interventions was 13·9 mm Hg (95% CI 13·4-14·4) in the ACCORD trial and 15·2 mm Hg (14·8-15·6) in SPRINT. At 3 years, the cumulative incidence of chronic kidney disease in the ACCORD trial was 10·0% (95% CI 8·8-11·4) with the intensive intervention and 4·1% (3·3-5·1) with the standard intervention (absolute risk difference 5·9%, 95% CI 4·3-7·5). Corresponding values in SPRINT were 3·5% (95% CI 2·9-4·2) and 1·0% (0·7-1·4; absolute risk difference 2·5%, 95% CI 1·8-3·2). The absolute risk difference was significantly higher in the ACCORD trial than in SPRINT (p=0·0001 for interaction). Intensive lowering of systolic blood pressure increased the risk of incident chronic kidney disease in people with and without type 2 diabetes. However, the absolute risk of incident chronic kidney disease was higher in people with type 2 diabetes. Our findings suggest the need for vigilance in monitoring kidney function during intensive antihypertensive drug treatment, particularly in adults with diabetes. Long-term studies are needed to understand the clinical implications of antihypertensive treatment-related reductions in eGFR. National Institutes of Health. Copyright © 2018 Elsevier Ltd. All rights reserved.

Spectral-Domain Optical Coherence Tomography Staging and Autofluorescence Imaging in Achromatopsia

PubMed Central

Greenberg, Jonathan P.; Sherman, Jerome; Zweifel, Sandrine A.; Chen, Royce W. S.; Duncker, Tobias; Kohl, Susanne; Baumann, Britta; Wissinger, Bernd; Yannuzzi, Lawrence A.; Tsang, Stephen H.

2015-01-01

Importance Evidence is mounting that achromatopsia is a progressive retinal degeneration, and treatments for this condition are on the horizon. Objectives To categorize achromatopsia into clinically identifiable stages using spectral-domain optical coherence tomography and to describe fundus autofluorescence imaging in this condition. Design, Setting, and Participants A prospective observational study was performed between 2010 and 2012 at the Edward S. Harkness Eye Institute, New York-Presbyterian Hospital. Participants included 17 patients (aged 10-62 years) with full-field electroretinography-confirmed achromatopsia. Main outcomes and Measures Spectral-domain optical coherence tomography features and staging system, fundus autofluorescence and near-infrared reflectance features and their correlation to optical coherence tomography, and genetic mutations served as the outcomes and measures. Results Achromatopsia was categorized into 5 stages on spectral-domain optical coherence tomography: stage 1 (2 patients [12%]), intact outer retina; stage 2 (2 patients [12%]), inner segment ellipsoid line disruption; stage 3 (5 patients [29%]), presence of an optically empty space; stage 4 (5 patients [29%]), optically empty space with partial retinal pigment epithelium disruption; and stage 5 (3 patients [18%]), complete retinal pigment epithelium disruption and/or loss of the outer nuclear layer. Stage 1 patients showed isolated hyperreflectivity of the external limiting membrane in the fovea, and the external limiting membrane was hyperreflective above each optically empty space. On near infrared reflectance imaging, the fovea was normal, hyporeflective, or showed both hyporeflective and hyperreflective features. All patients demonstrated autofluorescence abnormalities in the fovea and/or parafovea: 9 participants (53%) had reduced or absent autofluorescence surrounded by increased autofluorescence, 4 individuals (24%) showed only reduced or absent autofluorescence, 3 patients (18%) displayed only increased autofluorescence, and 1 individual (6%) exhibited decreased macular pigment contrast. Inner segment ellipsoid line loss generally correlated with the area of reduced autofluorescence, but hyperautofluorescence extended into this region in 2 patients (12%). Bilateral coloboma-like atrophic macular lesions were observed in 1 patient (6%). Five novel mutations were identified (4 in the CNGA3 gene and 1 in the CNGB3 gene). Conclusions and Relevance Achromatopsia often demonstrates hyperautofluorescence suggestive of progressive retinal degeneration. The proposed staging system facilitates classification of the disease into different phases of progression and may have therapeutic implications. PMID:24504161

Spectral-domain optical coherence tomography staging and autofluorescence imaging in achromatopsia.

PubMed

Greenberg, Jonathan P; Sherman, Jerome; Zweifel, Sandrine A; Chen, Royce W S; Duncker, Tobias; Kohl, Susanne; Baumann, Britta; Wissinger, Bernd; Yannuzzi, Lawrence A; Tsang, Stephen H

2014-04-01

IMPORTANCE Evidence is mounting that achromatopsia is a progressive retinal degeneration, and treatments for this condition are on the horizon. OBJECTIVES To categorize achromatopsia into clinically identifiable stages using spectral-domain optical coherence tomography and to describe fundus autofluorescence imaging in this condition. DESIGN, SETTING, AND PARTICIPANTS A prospective observational study was performed between 2010 and 2012 at the Edward S. Harkness Eye Institute, New York-Presbyterian Hospital. Participants included 17 patients (aged 10-62 years) with full-field electroretinography-confirmed achromatopsia. MAIN OUTCOMES AND MEASURES Spectral-domain optical coherence tomography features and staging system, fundus autofluorescence and near-infrared reflectance features and their correlation to optical coherence tomography, and genetic mutations served as the outcomes and measures. RESULTS Achromatopsia was categorized into 5 stages on spectral-domain optical coherence tomography: stage 1 (2 patients [12%]), intact outer retina; stage 2 (2 patients [12%]), inner segment ellipsoid line disruption; stage 3 (5 patients [29%]), presence of an optically empty space; stage 4 (5 patients [29%]), optically empty space with partial retinal pigment epithelium disruption; and stage 5 (3 patients [18%]), complete retinal pigment epithelium disruption and/or loss of the outer nuclear layer. Stage 1 patients showed isolated hyperreflectivity of the external limiting membrane in the fovea, and the external limiting membrane was hyperreflective above each optically empty space. On near infrared reflectance imaging, the fovea was normal, hyporeflective, or showed both hyporeflective and hyperreflective features. All patients demonstrated autofluorescence abnormalities in the fovea and/or parafovea: 9 participants (53%) had reduced or absent autofluorescence surrounded by increased autofluorescence, 4 individuals (24%) showed only reduced or absent autofluorescence, 3 patients (18%) displayed only increased autofluorescence, and 1 individual (6%) exhibited decreased macular pigment contrast. Inner segment ellipsoid line loss generally correlated with the area of reduced autofluorescence, but hyperautofluorescence extended into this region in 2 patients (12%). Bilateral coloboma-like atrophic macular lesions were observed in 1 patient (6%). Five novel mutations were identified (4 in the CNGA3 gene and 1 in the CNGB3 gene). CONCLUSIONS AND RELEVANCE Achromatopsia often demonstrates hyperautofluorescence suggestive of progressive retinal degeneration. The proposed staging system facilitates classification of the disease into different phases of progression and may have therapeutic implications.

Light-induced autofluorescence and diffuse reflectance spectroscopy in clinical diagnosis of skin cancer

NASA Astrophysics Data System (ADS)

Borisova, E.; Pavlova, E.; Kundurjiev, T.; Troyanova, P.; Genova, Ts.; Avramov, L.

2014-05-01

We investigated more than 500 clinical cases to receive the spectral properties of basal cell (136 patients) and squamous cell carcinoma (28), malignant melanoma (41) and different cutaneous dysplastic and benign cutaneous lesions. Excitation at 365, 385 and 405 nm using LEDs sources is applied to obtain autofluorescence spectra, and broad-band illumination in the region of 400-900 nm is used to detect diffuse reflectance spectra of all pathologies investigated. USB4000 microspectrometer (Ocean Optics Inc, USA) is applied as a detector and fiber-optic probe is used for delivery of the light. In the case of in vivo tumor measurements spectral shape and intensity changes are observed that are specific for a given type of lesion. Autofluorescence origins of the signals coming from skin tissues are mainly due to proteins, such as collagen, elastin, keratin, their cross-links, co-enzimes - NADH and flavins and endogenous porphyrins. Spectral features significant into diffuse spectroscopy diagnosis are related to the effects of re-absorption of hemoglobin and its forms, as well as melanin and its concentration in different pathologies. We developed significant database and revealed specific features for a large class of cutaneous neoplasia, using about 30 different spectral peculiarities to differentiate cutaneous tumors. Sensitivity and specificity obtained exceed 90%, which make optical biopsy very useful tool for clinical practice. These results are obtained in the frames of clinical investigations for development of significant "spectral features" database for the most common cutaneous malignant, dysplastic and benign lesions. In the forthcoming plans, our group tries to optimize the existing experimental system for optical biopsy of skin, and to introduce it and the diagnostic algorithms developed into clinical practice, based on the high diagnostic accuracy achieved.

Combining CPP-ACP with fluoride: a synergistic remineralization potential of artificially demineralized enamel or not?

NASA Astrophysics Data System (ADS)

El-Sayad, I. I.; Sakr, A. K.; Badr, Y. A.

2008-08-01

Background and objective: Minimal intervention dentistry (MID) calls for early detection and remineralization of initial demineralization. Laser fluorescence is efficient in detecting changes in mineral tooth content. Recaldent is a product of casein phosphopeptide-amorphous calcium phosphate (CPP- ACP) which delivers calcium and phosphate ions to enamel. A new product which also contains fluoride is launched in United States. The remineralizing potential of CPP- ACP per se, or when combined with 0.22% Fl supplied in an oral care gel on artificially demineralised enamel using laser fluorescence was investigated. Methods: Fifteen sound human molars were selected. Mesial surfaces were tested using He-Cd laser beam at 441.5nm with 18mW power as excitation source on a suitable set-up based on Spex 750 M monochromator provided with PMT for detection of collected auto-fluorescence from sound enamel. Mesial surfaces were subjected to demineralization for ten days. The spectra from demineralized enamel were measured. Teeth were then divided according to the remineralizing regimen into three groups: group I recaldent per se, group II recaldent combined with fluoride gel and group III artificial saliva as a positive control. After following these protocols for three weeks, the spectra from remineralized enamel from the three groups were measured. The spectra of enamel auto-fluorescence were recorded and normalized to peak intensity at about 540 nm to compare between spectra from sound, demineralized and remineralized enamel surfaces. Results: A slight red shift was noticed in spectra from demineralized enamel, while a blue shift may occur in remineralized enamel. Group II showed the highest remineralizing potential. Conclusions: Combining fluoride with CPP-ACP had a synergistic effect on enamel remineralization. In addition, laser auto-fluorescence is an accurate technique for assessment of changes in tooth enamel minerals.

Novel flashlamp-based time-resolved fluorescence microscope reduces autofluorescence for 30-fold contrast enhancement in environmental samples

NASA Astrophysics Data System (ADS)

Connally, Russell; Veal, Duncan; Piper, James A.

2003-07-01

The abundance of naturally fluorescing components (autofluorophors) encountered in environmentally sourced samples can greatly hinder the detection and identification of fluorescently labeled target using fluorescence microscopy. Time-resolved fluorescence microscopy (TRFM) is a technique that reduces the effects of autofluorescence through precisely controlled time delays. Lanthanide chelates have fluorescence lifetimes many orders of magnitude greater than typical autofluorophors, and persist in their luminescence long after autofluorescence has ceased. An intense short pulse of (UV) light is used to excite fluorescence in the sample and after a short delay period the longer persisting fluorescence from the chelate is captured with an image-intensified CCD camera. The choice of pulsed excitation source for TRFM has a large impact on the price and performance of the instrument. A flashlamp with a short pulse duration was selected for our instrument because of the high spectral energy in the UV region and short pulse length. However, flash output decays with an approximate lifetime of 18μs and the TRFM requires a long-lived chelate to ensure probe fluorescence is still visible after decay of the flash plasma. We synthesized a recently reported fluorescent chelate (BHHCT) and conjugated it to a monoclonal antibody directed against the water-borne parasite Giardia lamblia. Fluorescence lifetime of the construct was determined to be 339μs +/- 14μs and provided a 45-fold enhancement of labeled Giardia over background using a gate delay of 100μs. Despite the sub-optimal decay characteristics of the light pulse, flashlamps have many advantages compared to optical chopper wheels and modulated lasers. Their low cost, lack of vibration, ease of interface and small footprint are important factors to consider in TRFM design.

Deep UV autofluorescence microscopy for cell biology and tissue histology.

PubMed

Jamme, Frédéric; Kascakova, Slavka; Villette, Sandrine; Allouche, Fatma; Pallu, Stéphane; Rouam, Valérie; Réfrégiers, Matthieu

2013-07-01

Autofluorescence spectroscopy is a powerful tool for molecular histology and for following metabolic processes in biological samples as it does not require labelling. However, at the microscopic scale, it is mostly limited to visible and near infrared excitation of the samples. Several interesting and naturally occurring fluorophores can be excited in the UV and deep UV (DUV), but cannot be monitored in cellulo nor in vivo due to a lack of available microscopic instruments working in this wavelength range. To fulfil this need, we have developed a synchrotron-coupled DUV microspectrofluorimeter which is operational since 2010. An extended selection of endogenous autofluorescent probes that can be excited in DUV, including their spectral characteristics, is presented. The distribution of the probes in various biological samples, including cultured cells, soft tissues, bone sections and maize stems, is shown to illustrate the possibilities offered by this system. In this work we demonstrate that DUV autofluorescence is a powerful tool for tissue histology and cell biology. To fulfil this need, we have developed a synchrotron-coupled DUV microspectrofluorimeter which is operational since 2010. An extended selection of endogenous autofluorescent probes that can be excited in DUV, including their spectral characteristics, is presented. The distribution of the probes in various biological samples, including cultured cells, soft tissues, bone sections and maize stems, is shown to illustrate the possibilities offered by this system. In this work we demonstrate that DUV autofluorescence is a powerful tool for tissue histology and cell biology. In this work we demonstrate that DUV autofluorescence is a powerful tool for tissue histology and cell biology. © 2013 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.

Monte Carlo simulation of aorta autofluorescence

NASA Astrophysics Data System (ADS)

Kuznetsova, A. A.; Pushkareva, A. E.

2016-08-01

Results of numerical simulation of autofluorescence of the aorta by the method of Monte Carlo are reported. Two states of the aorta, normal and with atherosclerotic lesions, are studied. A model of the studied tissue is developed on the basis of information about optical, morphological, and physico-chemical properties. It is shown that the data obtained by numerical Monte Carlo simulation are in good agreement with experimental results indicating adequacy of the developed model of the aorta autofluorescence.

A simple protocol for attenuating the auto-fluorescence of cyanobacteria for optimized fluorescence in situ hybridization (FISH) imaging.

PubMed

Zeller, Perrine; Ploux, Olivier; Méjean, Annick

2016-03-01

Cyanobacteria contain pigments, which generate auto-fluorescence that interferes with fluorescence in situ hybridization (FISH) imaging of cyanobacteria. We describe simple chemical treatments using CuSO4 or H2O2 that significantly reduce the auto-fluorescence of Microcystis strains. These protocols were successfully applied in FISH experiments using 16S rRNA specific probes and filamentous cyanobacteria. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of an autofluorescence spectral database for the identification and classification of microbial extremophiles

NASA Astrophysics Data System (ADS)

Davis, Justin; Howard, Hillari; Hoover, Richard B.; Sabanayagam, Chandran R.

2010-09-01

Extremophiles are microorganisms that have adapted to severe conditions that were once considered devoid of life. The extreme settings in which these organisms flourish on Earth resemble many extraterrestrial environments. Identification and classification of extremophiles in situ (without the requirement for excessive handling and processing) can provide a basis for designing remotely operated instruments for extraterrestrial life exploration. An important consideration when designing such experiments is to prevent contamination of the environments. We are developing a reference spectral database of autofluorescence from microbial extremophiles using long-UV excitation (408 nm). Aromatic compounds are essential components of living systems, and biological molecules such as aromatic amino acids, nucleotides, porphyrins and vitamins can also exhibit fluorescence under long-UV excitation conditions. Autofluorescence spectra were obtained from a light microscope that additionally allowed observations of microbial geometry and motility. It was observed that all extremophiles studied displayed an autofluorescence peak at around 470 nm, followed by a long decay that was species specific. The autofluorescence database can potentially be used as a reference to identify and classify past or present microbial life in our solar system.

In-vivo fluorescence detection and imaging of porphyrin-producing bacteria in the human skin and in the oral cavity for diagnosis of acne vulgaris, caries, and squamous cell carcinoma

NASA Astrophysics Data System (ADS)

Koenig, Karsten; Schneckenburger, Herbert; Hemmer, Joerg; Tromberg, Bruce J.; Steiner, Rudolf W.

1994-05-01

Certain bacteria are able to synthesize metal-free fluorescent porphyrins and can therefore be detected by sensitive autofluorescence measurements in the red spectral region. The porphyrin-producing bacterium Propionibacterium acnes, which is involved in the pathogenesis of acne vulgaris, was localized in human skin. Spectrally resolved fluorescence images of bacteria distribution in the face were obtained by a slow-scan CCD camera combined with a tunable liquid crystal filter. The structured autofluorescence of dental caries and dental plaque in the red is caused by oral bacteria, like Bacteroides or Actinomyces odontolyticus. `Caries images' were created by time-gated imaging in the ns-region after ultrashort laser excitation. Time-gated measurements allow the suppression of backscattered light and non-porphyrin autofluorescence. Biopsies of oral squamous cell carcinoma exhibited red autofluorescence in necrotic regions and high concentrations of the porphyrin-producing bacterium Pseudomonas aerigunosa. These studies suggest that the temporal and spectral characteristics of bacterial autofluorescence can be used in the diagnosis and treatment of a variety of diseases.

Development of an Autofluorescence Spectral Database for the Identification and Classification of Microbial Extremophiles

NASA Technical Reports Server (NTRS)

Sabanayagam, Chandran; Howard, Hillari; Hoover, Richard B.

2010-01-01

Extremophiles are microorganisms that have adapted to severe conditions that were once considered devoid of life. The extreme settings in which these organisms flourish on earth resemble many extraterrestrial environments. Identification and classification of extremophiles in situ (without the requirement for excessive handling and processing) can provide a basis for designing remotely operated instruments for extraterrestrial life exploration. An important consideration when designing such experiments is to prevent contamination of the environments. We are developing a reference spectral database of autofluorescence from microbial extremophiles using long-UV excitation (405 nm). Aromatic compounds are essential components of living systems, and biological molecules such as aromatic amino acids, nucleotides, porphyrins and vitamins can also exhibit fluorescence under long-UV excitation conditions. Autofluorescence spectra were obtained from a confocal microscope that additionally allowed observations of microbial geometry and motility. It was observed that all extremophiles studied displayed an autofluorescence peak at around 470 nm, followed by a long decay that was species specific. The autofluorescence database can potentially be used as a reference to identify and classify past or present microbial life in our solar system.

Reduced-illuminance autofluorescence imaging in ABCA4-associated retinal degenerations

NASA Astrophysics Data System (ADS)

Cideciyan, Artur V.; Swider, Malgorzata; Aleman, Tomas S.; Roman, Marisa I.; Sumaroka, Alexander; Schwartz, Sharon B.; Stone, Edwin M.; Jacobson, Samuel G.

2007-05-01

The health of the retinal pigment epithelium (RPE) can be estimated with autofluorescence (AF) imaging of lipofuscin, which accumulates as a byproduct of retinal exposure to light. Lipofuscin may be toxic to the RPE, and its toxicity may be enhanced by short-wavelength (SW) illumination. The high-intensity and SW excitation light used in conventional AF imaging could, at least in principle, increase the rate of lipofuscin accumulation and/or increase its toxicity. We considered two reduced-illuminance AF imaging (RAFI) methods as alternatives to conventional AF imaging. RAFI methods use either near-infrared (NIR) light or reduced-radiance SW illumination for excitation of fluorophores. We quantified the distribution of RAFI signals in relation to retinal structure and function in patients with the prototypical lipofuscin accumulation disease caused by mutations in ABCA4. There was evidence for two subclinical stages of macular ABCA4 disease involving hyperautofluorescence of both SW- and NIR-RAFI with and without associated loss of visual function. Use of RAFI methods and microperimetry in future clinical trials involving lipofuscinopathies should allow quantification of subclinical disease expression and progression without subjecting the diseased retina/RPE to undue light exposure.

High efficiency upconversion nanophosphors for high-contrast bioimaging

NASA Astrophysics Data System (ADS)

Alkahtani, Masfer H.; Alghannam, Fahad S.; Sanchez, Carlos; Gomes, Carmen L.; Liang, Hong; Hemmer, Philip R.

2016-12-01

Upconversion nanoparticles (UCNPs) are of interest because they allow suppression of tissue autofluorescence and are therefore visible deep inside biological tissue. Compared to upconversion dyes, UCNPs have a lower pump intensity threshold, better photostability, and less toxicity. Recently, YVO4: Er+3, Yb+3 nanoparticles were shown to exhibit strong up-conversion luminescence with a relatively low 10 kW cm-2 excitation intensity even in water, which makes them excellent bio-imaging candidates. Herein, we investigate their use as internal probes in insects by injecting YVO4 : Er+3, Yb+3 nanoparticles into fire ants as a biological model, and obtain 2D optical images with 980 nm illumination. High-contrast images with high signal-to-noise ratio are observed by detecting the up-conversion fluorescence as the excitation laser is scanned.

Imaging Lenticular Autofluorescence in Older Subjects

PubMed Central

Charng, Jason; Tan, Rose; Luu, Chi D.; Sadigh, Sam; Stambolian, Dwight; Guymer, Robyn H.; Jacobson, Samuel G.; Cideciyan, Artur V.

2017-01-01

Purpose To evaluate whether a practical method of imaging lenticular autofluorescence (AF) can provide an individualized measure correlated with age-related lens yellowing in older subjects undergoing tests involving shorter wavelength lights. Methods Lenticular AF was imaged with 488-nm excitation using a confocal scanning laser ophthalmoscope (cSLO) routinely used for retinal AF imaging. There were 75 older subjects (ages 47–87) at two sites; a small cohort of younger subjects served as controls. At one site, the cSLO was equipped with an internal reference to allow quantitative AF measurements; at the other site, reduced-illuminance AF imaging (RAFI) was used. In a subset of subjects, lens density index was independently estimated from dark-adapted spectral sensitivities performed psychophysically. Results Lenticular AF intensity was significantly higher in the older eyes than the younger cohort when measured with the internal reference (59.2 ± 15.4 vs. 134.4 ± 31.7 gray levels; P < 0.05) as well as when recorded with RAFI without the internal reference (10.9 ± 1.5 vs. 26.1 ± 5.7 gray levels; P < 0.05). Lenticular AF was positively correlated with age; however, there could also be large differences between individuals of similar age. Lenticular AF intensity correlated well with lens density indices estimated from psychophysical measures. Conclusions Lenticular AF measured with a retinal cSLO can provide a practical and individualized measure of lens yellowing, and may be a good candidate to distinguish between preretinal and retinal deficits involving short-wavelength lights in older eyes. PMID:28973367

Mueller-matrix mapping of optically anisotropic fluorophores of biological tissues in the diagnosis of cancer

NASA Astrophysics Data System (ADS)

Ushenko, Yu A.; Sidor, M. I.; Bodnar, G. B.; Koval', G. D.

2014-08-01

We report the results of studying the polarisation manifestations of laser autofluorescence of optically anisotropic structures in biological tissues. A Mueller-matrix model is proposed to describe their complex anisotropy (linear and circular birefringence, linear and circular dichroism). The relationship is established between the mechanisms of optical anisotropy and polarisation manifestations of laser autofluorescence of histological sections of rectal tissue biopsy in different spectral regions. The ranges of changes in the statistical moments of the 1st-to-4th orders, which describe the distribution of the azimuth-invariant elements of Mueller matrices of rectal tissue autofluorescence, are found. Effectiveness of laser autofluorescence polarimetry is determined and the histological sections of biopsy of benign (polyp) and malignant (adenocarcinoma) tumours of the rectal wall are differentiated for the first time.

Fundus autofluorescence in retinal artery occlusion: A more precise diagnosis.

PubMed

Bacquet, J-L; Sarov-Rivière, M; Denier, C; Querques, G; Riou, B; Bonin, L; Barreau, E; Labetoulle, M; Rousseau, A

2017-10-01

Retinal artery occlusion (RAO) is a medical emergency associated with a high risk of cerebral vascular accident and other cardiovascular events. Among patients with non-arteritic RAO, a retinal embolus is observed in approximately 40% of cases. Fundus examination and retinography are not reliable to predict the nature of the emboli. We report three consecutive cases of central and branch RAO that were investigated with fundus autofluorescence, fluorescein angiography and color retinal photographs. All patients underwent complete neurological and cardiovascular workups, with brain imaging, cardiac Doppler ultrasound, carotid Dopplers and Holter ECG's, to determine the underlying mechanism of retinal embolism. In the three cases, aged 77.7±4 years (2 women and 1 man), fundus autofluorescence demonstrated hyperautofluorescent emboli. In two cases, it allowed visualization of emboli that were not detected with fundus examination or retinography. The cardiovascular work-up demonstrated atheromatous carotid or aortic plaques in all patients. In one case, it permitted the diagnosis of RAO. Two of the three cases were considered to be of atherosclerotic origin and one of undefined origin. Fundus autofluorescence may help to detect and characterize retinal emboli. Since lipofuscin, which is present in large quantity in atherosclerotic plaques, is the main fluorophore detected with fundus autofluorescence, this non-invasive and simple examination may give information about the underlying mechanism of retinal embolism, and thus impact the etiologic assessment of RAO. Additional studies are necessary to confirm this potential role of autofluorescence. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Detection of colorectal cancer using time-resolved autofluorescence spectrometer

NASA Astrophysics Data System (ADS)

Fu, Sheng; Kwek, Leong-Chuan; Chia, Teck-Chee; Lim, Chu-Sing; Tang, Choong-Leong; Ang, Wuan-Suan; Zhou, Miao-Chang; Loke, Po-Ling

2006-04-01

As we know Quantum mechanics is a mathematical theory that can describe the behavior of objects that are at microscopic level. Time-resolved autofluorescence spectrometer monitors events that occur during the lifetime of the excited state. This time ranges from a few picoseconds to hundreds of nanoseconds. That is an extremely important advance as it allows environmental parameters to be monitored in a spatially defined manner in the specimen under study. This technique is based on the application of Quantum Mechanics. This principle is applied in our project as we are trying to use different fluorescence spectra to detect biological molecules commonly found in cancerous colorectal tissue and thereby differentiate the cancerous and non-cancerous colorectal polyps more accurately and specifically. In this paper, we use Fluorescence Lifetime Spectrometer (Edinburgh Instruments FL920) to measure decay time of autofluorescence of colorectal cancerous and normal tissue sample. All specimens are from Department of Colorectal Surgery, Singapore General Hospital. The tissues are placed in the time-resolved autofluorescence instrument, which records and calculates the decay time of the autofluorescence in the tissue sample at the excitation and emission wavelengths pre-determined from a conventional spectrometer. By studying the decay time,τ, etc. for cancerous and normal tissue, we aim to present time-resolved autofluorescence as a feasible technique for earlier detection of malignant colorectal tissues. By using this concept, we try to contribute an algorithm even an application tool for real time early diagnosis of colorectal cancer for clinical services.

Progression of Stargardt Disease as Determined by Fundus Autofluorescence in the Retrospective Progression of Stargardt Disease Study (ProgStar Report No. 9).

PubMed

Strauss, Rupert W; Muñoz, Beatriz; Ho, Alexander; Jha, Anamika; Michaelides, Michel; Cideciyan, Artur V; Audo, Isabelle; Birch, David G; Hariri, Amir H; Nittala, Muneeswar G; Sadda, SriniVas; West, Sheila; Scholl, Hendrik P N

2017-11-01

Sensitive outcome measures for disease progression are needed for treatment trials of Stargardt disease. To describe the yearly progression rate of atrophic lesions in the retrospective Progression of Stargardt Disease study. A multicenter retrospective cohort study was conducted at tertiary referral centers in the United States and Europe. A total of 251 patients aged 6 years or older at baseline, harboring disease-causing variants in ABCA4 (OMIM 601691), enrolled in the study from 9 centers between August 2, 2013, and December 12, 2014; of these patients, 215 had at least 2 gradable fundus autofluorescence images with atrophic lesion(s) present in at least 1 eye. Areas of definitely decreased autofluorescence (DDAF) and questionably decreased autofluorescence were quantified by a reading center. Progression rates were estimated from linear mixed models with time as the independent variable. Yearly rate of progression using the growth of atrophic lesions measured by fundus autofluorescence. A total of 251 participants (458 study eyes) were enrolled. Images from 386 eyes of 215 participants (126 females and 89 males; mean [SD] age, 29.9 [14.7] years; mean [SD] age of onset of symptoms, 21.9 [13.3] years) showed atrophic lesions present on at least 2 visits and were graded for 2 (156 eyes), 3 (174 eyes), or 4 (57 eyes) visits. A subset of 224 eyes (123 female participants and 101 male participants; mean [SD] age, 33.0 [15.1] years) had areas of DDAF present on at least 2 visits; these eyes were included in the estimation of the progression of the area of DDAF. At the first visit, DDAF was present in 224 eyes (58.0%), with a mean (SD) lesion size of 2.2 (2.7) mm2. The total mean (SD) area of decreased autofluorescence (DDAF and questionably decreased autofluorescence) at first visit was 2.6 (2.8) mm2. Mean progression of DDAF was 0.51 mm2/y (95% CI, 0.42-0.61 mm2/y), and of total decreased fundus autofluorescence was 0.35 mm2/y (95% CI, 0.28-0.43 mm2/y). Rates of progression depended on the initial size of the lesion. In Stargardt disease with DDAF lesions, fundus autofluorescence may serve as a monitoring tool for interventional clinical trials that aim to slow disease progression. Rates of progression depended mainly on initial lesion size.

Skin Autofluorescence and Subclinical Atherosclerosis in Mild to Moderate Chronic Kidney Disease: A Case-Control Study

PubMed Central

Sánchez, Enric; Betriu, Àngels; Arroyo, David; López, Carolina; Hernández, Marta; Rius, Ferran; Fernández, Elvira

2017-01-01

Advanced glycation end-products (AGEs) are increased and predict mortality in patients with chronic kidney disease (CKD) who are undergoing hemodialysis, irrespective of the presence of type 2 diabetes. However, little information exits about the relationship between AGEs and subclinical atherosclerosis at the early stages of CKD. A case-control study was performed including 87 patients with mild-to-moderate stages of CKD (glomerular filtration rate from 89 to 30 ml/min/per 1.73m2) and 87 non-diabetic non-CKD subjects matched by age, gender, body mass index, and waist circumference. Skin autofluorescence (AF), a non-invasive assessment of AGEs, was measured. The presence of atheromatous disease in carotid and femoral arteries was evaluated using vascular ultrasound, and vascular age and SCORE risk were estimated. Patients with mild-to-moderate stages of CKD showed an increase in skin AF compared with control subjects (2.5±0.6 vs. 2.2±0.4 AU, p<0.001). A skin AF value >2.0 AU was accompanied by a 3-fold increased risk of detecting the presence of an atheromathous plaque (OR 3.0, 95% CI 1.4–6.5, p = 0.006). When vascular age was assessed through skin AF, subjects with CKD were almost 12 years older than control subjects (70.3±25.5 vs. 58.5±20.2 years, p = 0.001). Skin AF was negatively correlated with glomerular filtration rate (r = -0.354, p<0.001) and LDL-cholesterol (r = -0.269, p = 0.001), and positively correlated with age (r = 0.472, p<0.001), pulse pressure (r = 0.238, p = 0.002), and SCORE risk (r = 0.451, p<0.001). A stepwise multivariate regression analysis showed that age and glomerular filtration rate independently predicted skin AF (R2 = 0.289, p<0.001). Skin AF is elevated in patients with mild-to-moderate CKD compared with control subjects. This finding may be independently associated with the glomerular filtration rate and the presence of subclinical atheromatous disease. Therefore, the use of skin AF may help to accurately evaluate the real cardiovascular risk at the early stages of CKD. PMID:28141808

The effect of trypan blue treatment on autofluorescence of fixed cells.

PubMed

Shilova, Olga N; Shilov, Evgeny S; Deyev, Sergey M

2017-09-01

Controlling background fluorescence remains an important challenge in flow cytometry, as autofluorescence can interfere with the detection of chromophores. Furthermore, experimental procedures can also affect cellular fluorescence in certain regions of the emission spectrum. In this work, the effects of fixation, permeabilization, and heating on cellular autofluorescence are analyzed in various spectral regions, along with the influence of trypan blue as a quenching dye for these treatments. The impact of these procedures on the staining of SK-BR-3 cells with a dim green fluorophore, a miniSOG (mini Singlet Oxygen Generator) flavoprotein in the form of the recombinant protein DARPin-miniSOG, is also evaluated. The data presented here indicate that fixation of certain types of cells leads to noticeable increase of the autofluorescence. Our results also suggest that trypan blue should be used as an autofluorescence quencher only with bright green emitters since it interferes with the fluorescent signal in a longer-wavelength region of the spectrum and as a result causes reduction of the signal from dim green fluorescent agents. © 2017 International Society for Advancement of Cytometry. © 2017 International Society for Advancement of Cytometry.

The BALB/c mouse: Effect of standard vivarium lighting on retinal pathology during aging

PubMed Central

Bell, Brent A.; Kaul, Charles; Bonilha, Vera L.; Rayborn, Mary E.; Shadrach, Karen; Hollyfield, Joe G.

2015-01-01

BALB/cJ mice housed under normal vivarium lighting conditions can exhibit profound retinal abnormalities, including retinal infoldings, autofluorescent inflammatory cells, and photoreceptor degeneration. To explore the sensitivity of the outer retina to cyclic lighting during aging, a cohort of BALB/cJ mice was evaluated with Scanning Laser Ophthalmoscopy (SLO), Spectral-Domain Optical Coherence Tomography (OCT) and conventional histopathology. Mice were bred and reared in a low-illuminance (extracage/intracage: 13 lx/1 lx) vivarium under cyclic light (14 h light: 10 h dark). Retinal imaging (around postnatal day 70) was performed to screen for any pre-existing abnormalities and to establish a baseline. Mice with normal retinas were separated into groups (A, B, C) and placed on bottom (Groups A & B) or top (Group C) of the cage racks where cage illumination was <10 & 150 lx respectively. Experimental groups B & C were imaged multiple times over a 17 month period. Mice from group A (controls) were imaged only once post-baseline at various times for comparison to groups B & C. Mice were assessed by histology at 8, 15, 20, 36, and 56 weeks and immunohistochemistry at 15 weeks post-baseline. SLO and OCT retinal images were measured and the resulting trends displayed as a function of age and light exposure. Retinal lesions (RL) and autofluorescent foci (AFF) were identified with histology as photoreceptor layer infoldings (IF) and localized microglia/macrophages (MM), respectively. Few RL and AFF were evident at baseline. Retinal infoldings were the earliest changes followed by subjacent punctate autofluorescent MM. The colocalization of IF and MM suggests a causal relationship. The incidence of these pathological features increased in all groups relative to baseline. OCT imaging revealed thinning of the outer nuclear layer (ONL) in all groups at 1 year relative to baseline. ONL thinning followed an exponential rate of change but the decay constant varied depending on intensity of illumination of the groups. Advanced age and top row illuminance conditions resulted in significant photoreceptor cell loss as judged by decreased thickness of the ONL. Photoreceptor loss was preceded by both retinal infoldings and the presence of autofluorescent inflammatory cells in the outer retina, suggesting that these changes are early indicators of light toxicity in the BALB/cJ mouse. PMID:25895728

The BALB/c mouse: Effect of standard vivarium lighting on retinal pathology during aging.

PubMed

Bell, Brent A; Kaul, Charles; Bonilha, Vera L; Rayborn, Mary E; Shadrach, Karen; Hollyfield, Joe G

2015-06-01

BALB/cJ mice housed under normal vivarium lighting conditions can exhibit profound retinal abnormalities, including retinal infoldings, autofluorescent inflammatory cells, and photoreceptor degeneration. To explore the sensitivity of the outer retina to cyclic lighting during aging, a cohort of BALB/cJ mice was evaluated with Scanning Laser Ophthalmoscopy (SLO), Spectral-Domain Optical Coherence Tomography (OCT) and conventional histopathology. Mice were bred and reared in a low-illuminance (extracage/intracage: 13 lx/1 lx) vivarium under cyclic light (14 h light: 10 h dark). Retinal imaging (around postnatal day 70) was performed to screen for any pre-existing abnormalities and to establish a baseline. Mice with normal retinas were separated into groups (A, B, C) and placed on bottom (Groups A & B) or top (Group C) of the cage racks where cage illumination was <10 & 150 lx respectively. Experimental groups B & C were imaged multiple times over a 17 month period. Mice from group A (controls) were imaged only once post-baseline at various times for comparison to groups B & C. Mice were assessed by histology at 8, 15, 20, 36, and 56 weeks and immunohistochemistry at 15 weeks post-baseline. SLO and OCT retinal images were measured and the resulting trends displayed as a function of age and light exposure. Retinal lesions (RL) and autofluorescent foci (AFF) were identified with histology as photoreceptor layer infoldings (IF) and localized microglia/macrophages (MM), respectively. Few RL and AFF were evident at baseline. Retinal infoldings were the earliest changes followed by subjacent punctate autofluorescent MM. The colocalization of IF and MM suggests a causal relationship. The incidence of these pathological features increased in all groups relative to baseline. OCT imaging revealed thinning of the outer nuclear layer (ONL) in all groups at 1 year relative to baseline. ONL thinning followed an exponential rate of change but the decay constant varied depending on intensity of illumination of the groups. Advanced age and top row illuminance conditions resulted in significant photoreceptor cell loss as judged by decreased thickness of the ONL. Photoreceptor loss was preceded by both retinal infoldings and the presence of autofluorescent inflammatory cells in the outer retina, suggesting that these changes are early indicators of light toxicity in the BALB/cJ mouse. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sudan Black B masks Mycobacterium avium subspecies paratuberculosis immunofluorescent antibody labeling

USDA-ARS?s Scientific Manuscript database

Autofluorescence and non-specific immunofluorescent labeling are common challenges associated with immunofluorescence experiments. Autofluorescence typically demonstrates a broad emission spectrum, increasing the potential for overlap with experiments that utilize multiple fluorophores. During immun...

Two-photon excited autofluorescence imaging of human retinal pigment epithelial cells

NASA Astrophysics Data System (ADS)

Han, Meng; Blindewald-Wittich, Almut; Holz, Frank G.; Giese, Günter; Niemz, Markolf H.; Snyder, Sarah; Sun, Hui; Yu, Jiayi; Agopov, Michael; La Schiazza, Olivier; Bille, Josef F.

2006-01-01

Degeneration of retinal pigment epithelial (RPE) cells severely impairs the visual function of retina photoreceptors. However, little is known about the events that trigger the death of RPE cells at the subcellular level. Two-photon excited autofluorescence (TPEF) imaging of RPE cells proves to be well suited to investigate both the morphological and the spectral characteristics of the human RPE cells. The dominant fluorophores of autofluorescence derive from lipofuscin (LF) granules that accumulate in the cytoplasm of the RPE cells with increasing age. Spectral TPEF imaging reveals the existence of abnormal LF granules with blue shifted autofluorescence in RPE cells of aging patients and brings new insights into the complicated composition of the LF granules. Based on a proposed two-photon laser scanning ophthalmoscope, TPEF imaging of the living retina may be valuable for diagnostic and pathological studies of age related eye diseases.

Green autofluorescence, a double edged monitoring tool for bacterial growth and activity in micro-plates

NASA Astrophysics Data System (ADS)

Mihalcescu, Irina; Van-Melle Gateau, Mathilde; Chelli, Bernard; Pinel, Corinne; Ravanat, Jean-Luc

2015-12-01

The intrinsic green autofluorescence of an Escherichia coli culture has long been overlooked and empirically corrected in green fluorescent protein (GFP) reporter experiments. We show here, by using complementary methods of fluorescence analysis and HPLC, that this autofluorescence, principally arise from the secreted flavins in the external media. The cells secrete roughly 10 times more than what they keep inside. We show next that the secreted flavin fluorescence can be used as a complementary method in measuring the cell concentration particularly when the classical method, based on optical density measure, starts to fail. We also demonstrate that the same external flavins limit the dynamical range of GFP quantification and can lead to a false interpretation of lower global dynamic range of expression than what really happens. In the end we evaluate different autofluorescence correction methods to extract the real GFP signal.

Miniature spectrometer and multispectral imager as a potential diagnostic aid in dermatology

NASA Astrophysics Data System (ADS)

Zeng, Haishan; MacAulay, Calum E.; McLean, David I.; Lui, Harvey; Palcic, Branko

1995-04-01

A miniature spectrometer system has been constructed for both reflectance and autofluorescence spectral measurements of skin. The system is based on PC plug-in spectrometer, therefore, it is miniature and easy to operate. The spectrometer has been used clinically to collect spectral data from various skin lesions including skin cancer. To date, 48 patients with a total of 71 diseased skin sites have been measured. Analysis of these preliminary data suggests that unique spectral characteristics exist for certain types of skin lesions, i.e. seborrheic keratosis, psoriasis, etc.. These spectral characteristics will help the differential diagnosis in Dermatology practice. In conjunction with the spectral point measurements, we are building and testing a multispectral imaging system to measure the spatial distribution of skin reflectance and autofluorescence. Preliminary results indicate that a cutaneous squamous cell carcinoma has a weak autofluorescence signal at the edge of the lesion, but a higher autofluorescence signal in the central area.

Laser autofluorescence polarimetry of optically anisotropic structures of biological tissues in cancer diagnostics

NASA Astrophysics Data System (ADS)

Ushenko, Yu. A.

2015-06-01

The results of a new physical study of polarization manifestations of laser autofluorescence of optically anisotropic structures in human female reproductive tissues are presented. A Mueller-matrix model of describing the complex anisotropy (linear and circular birefringence, linear and circular dichroism) of such biological layers is proposed. Interrelations between mechanisms of optical anisotropy and polarization manifestations of laser autofluorescence of histological layers of the uterine cervix tissue in different spectral regions are determined. Magnitudes and variation ranges of statistical moments from the first to the fourth order describing the distributions of azimuthally stable elements of Mueller matrices of autofluorescence in human female reproductive tissues in different physiological states are found. The informative value of the proposed method is determined and the differentiation of histological biopsy sections of benign (dysplasia) and malignant (adenocarcinoma) uterine cervix tumors is implemented for the first time.

Mueller-matrix of laser-induced autofluorescence of polycrystalline films of dried peritoneal fluid in diagnostics of endometriosis

NASA Astrophysics Data System (ADS)

Ushenko, Yuriy A.; Koval, Galina D.; Ushenko, Alexander G.; Dubolazov, Olexander V.; Ushenko, Vladimir A.; Novakovskaia, Olga Yu.

2016-07-01

This research presents investigation results of the diagnostic efficiency of an azimuthally stable Mueller-matrix method of analysis of laser autofluorescence of polycrystalline films of dried uterine cavity peritoneal fluid. A model of the generalized optical anisotropy of films of dried peritoneal fluid is proposed in order to define the processes of laser autofluorescence. The influence of complex mechanisms of both phase (linear and circular birefringence) and amplitude (linear and circular dichroism) anisotropies is taken into consideration. The interconnections between the azimuthally stable Mueller-matrix elements characterizing laser autofluorescence and different mechanisms of optical anisotropy are determined. The statistical analysis of coordinate distributions of such Mueller-matrix rotation invariants is proposed. Thereupon the quantitative criteria (statistic moments of the first to the fourth order) of differentiation of polycrystalline films of dried peritoneal fluid, group 1 (healthy donors) and group 2 (uterus endometriosis patients), are determined.

Photoproduct formation of endogeneous protoporphyrin and its photodynamic activity

NASA Astrophysics Data System (ADS)

Koenig, Karsten; Schneckenburger, Herbert; Rueck, Angelika C.; Auchter, S.

1991-11-01

Human skin shows a strong autofluorescence in the red spectral region caused on the porphyrin production of the Gram positive lipophile skin bacterium Propionibacterium acnes. Irradiation of these bacteria reduces the integral fluorescence intensity and induces the formation of fluorescent photoproducts. The fluorescence band at around 670 nm and the decay times of around 1 ns and 5 ns are typical for protoporphyrin products. The photoproduct formation is connected with an increased absorption in the red spectral region. However the photodynamic activity of these photoproducts determined by scattering measurements on human erythrocytes is lower than that of protoporphyrin IX. 1:

Detection of melanomas by digital imaging of spectrally resolved UV light-induced autofluorescence of human skin

NASA Astrophysics Data System (ADS)

Chwirot, B. W.; Chwirot, S.; Jedrzejczyk, W.; Redzinski, J.; Raczynska, A. M.; Telega, K.

2001-07-01

We studied spectral and spatial distributions of the intensity of the ultraviolet light-excited fluorescence of human skin. Our studied performed in situ in 162 patients with malignant and non-malignant skin lesions resulted in a new method of detecting melanomas in situ using digital imaging of the spectrally resolved fluorescence. With our diagnostic algorithm we could successfully detect 88.5% of the cases of melanoma in the group of patients subject to examinations with the fluorescence method. A patent application for the method has been submitted to the Patent Office in Warsaw.

Multiple high-intensity focused ultrasound probes for kidney-tissue ablation.

PubMed

Häcker, Axel; Chauhan, Sunita; Peters, Kristina; Hildenbrand, Ralf; Marlinghaus, Ernst; Alken, Peter; Michel, Maurice Stephan

2005-10-01

To investigate kidney-tissue ablation by high-intensity focused ultrasound (HIFU) using multiple and single probes. Ultrasound beams (1.75 MHz) produced by a piezoceramic element (focal distance 80 mm) were focused at the center of renal parenchyma. One of the three probes (mounted on a jig) could also be used for comparison with a single probe at comparable power ratings. Lesion dimensions were examined in perfused and unperfused ex vivo porcine kidneys at different power levels (40, 60, and 80 W) and treatment times (4, 6, and 8 seconds). At identical power levels, the lesions induced by multiple probes were larger than those induced by a single probe. Lesion size increased with increasing pulse duration and generator power. The sizes and shapes of the lesions were predictably repeatable in all samples. Lesions in perfused kidneys were smaller than those in unperfused kidneys. Ex vivo, kidney-tissue ablation by means of multiple HIFU probes offers significant advantages over single HIFU probes in respect of lesion size and formation. These advantages need to be confirmed by tests in vivo at higher energy levels.

Integrated scanning laser ophthalmoscopy and optical coherence tomography for quantitative multimodal imaging of retinal degeneration and autofluorescence

NASA Astrophysics Data System (ADS)

Issaei, Ali; Szczygiel, Lukasz; Hossein-Javaheri, Nima; Young, Mei; Molday, L. L.; Molday, R. S.; Sarunic, M. V.

2011-03-01

Scanning Laser Ophthalmoscopy (SLO) and Coherence Tomography (OCT) are complimentary retinal imaging modalities. Integration of SLO and OCT allows for both fluorescent detection and depth- resolved structural imaging of the retinal cell layers to be performed in-vivo. System customization is required to image rodents used in medical research by vision scientists. We are investigating multimodal SLO/OCT imaging of a rodent model of Stargardt's Macular Dystrophy which is characterized by retinal degeneration and accumulation of toxic autofluorescent lipofuscin deposits. Our new findings demonstrate the ability to track fundus autofluorescence and retinal degeneration concurrently.

[Geographic atrophy imaging using fundus autofluorescence method].

PubMed

Dolar-Szczasny, Joanna; Święch-Zubilewicz, Anna; Mackiewicz, Jerzy

2015-01-01

Geographic atrophy is a manifestation of the advanced age-related macular degeneration and form of irreversible atrophy of retinal pigment epithelium and photoreceptor layer. Early detection of changes and the ability to evaluate disease progression accurately constitute a key problem in diagnosis and treatment planning. Fundus autofluorescence is a relatively new imaging method considered nowadays to be the best in diagnosis and observing the natural or treatment-altered course of disease. High resolution images showing the 3D distribution of retinal pigment epithelium autofluorescence as lipofuscin index can be obtained owing to the launch of the confocal scanning laser ophthalmoscope.

DISCORDANCE BETWEEN BLUE-LIGHT AUTOFLUORESCENCE AND NEAR-INFRARED AUTOFLUORESCENCE IN AGE-RELATED MACULAR DEGENERATION.

PubMed

Heiferman, Michael J; Fawzi, Amani A

2016-12-01

To identify the origin and significance of discordance between blue-light autofluorescence (BL-AF; 488 nm) and near-infrared autofluorescence (NI-AF; 787 nm) in patients with age-related macular degeneration (AMD). A total of 86 eyes of 59 patients with a diagnosis of AMD were included in this cross-sectional study conducted between March 9, 2015 and May 1, 2015. A masked observer examined the BL-AF, NI-AF, and spectral-domain optical coherence tomography images. Areas with discordance of autofluorescence patterns between NI-AF and BL-AF images were correlated with structural findings at the corresponding location in optical coherence tomography scans. Seventy-nine eyes had discordance between BL-AF and NI-AF. The most common optical coherence tomography finding accounting for these discrepancies was pigment migration accounting for 35 lesions in 21 eyes. The most clinically relevant finding was geographic atrophy missed on BL-AF in 7 eyes. Our findings indicate that variations in the distribution of lipofuscin, melanin and melanolipofuscin account for the majority of discordance between BL-AF and NI-AF. Given our finding of missed geographic atrophy lesions on BL-AF in 24% of eyes with geographic atrophy (7/29 eyes), clinicians should consider multimodal imaging, including NI-AF and optical coherence tomography, especially in clinical trials of geographic atrophy.

Discordance between Blue-Light Autofluorescence and Near-Infrared Autofluorescence in Age-Related Macular Degeneration

PubMed Central

Heiferman, Michael J.; Fawzi, Amani A.

2016-01-01

Purpose To identify the origin and significance of discordance between blue-light autofluorescence (BL-AF; 488nm) and near-infrared autofluorescence (NI-AF; 787nm) in patients with age-related macular degeneration (AMD). Methods A total of 86 eyes of 59 patients with a diagnosis of AMD were included in this cross-sectional study conducted between March 9, 2015 and May 1, 2015. A masked observer examined the BL-AF, NI-AF, and spectral-domain optical coherence tomography (OCT) images. Areas with discordance of autofluorescence patterns between NI-AF and BL-AF images were correlated with structural findings at the corresponding location in OCT scans. Results 79 eyes had discordance between BL-AF and NI-AF. The most common OCT finding accounting for these discrepancies was pigment migration accounting for 35 lesions in 21 eyes. The most clinically relevant finding was geographic atrophy missed on BL-AF in seven eyes. Conclusions Our findings indicate that variations in the distribution of lipofuscin, melanin and melanolipofuscin account for the majority of discordance between BL-AF and NI-AF. Given our finding of missed geographic atrophy lesions on BL-AF in 24% of eyes with geographic atrophy (7/29 eyes), clinicians should consider multimodal imaging, including NI-AF and OCT, especially in clinical trials of geographic atrophy. PMID:28005672

Fundus autofluorescence and optical coherence tomographic findings in acute zonal occult outer retinopathy.

PubMed

Fujiwara, Takamitsu; Imamura, Yutaka; Giovinazzo, Vincent J; Spaide, Richard F

2010-09-01

The purpose of this study was to investigate the fundus autofluorescence and optical coherence tomography findings in eyes with acute zonal occult outer retinopathy (AZOOR). A retrospective observational case series of the fundus autofluorescence and spectral domain optical coherence tomography in a series of patients with AZOOR. There were 19 eyes of 11 patients (10 women), who had a mean age of 49.1 +/- 13.9 years. Fundus autofluorescence abnormalities were seen in 17 of the 19 eyes, were more common in the peripapillary area, and were smaller in extent than the optical coherence tomography abnormalities. Nine eyes showed progression of hypoautofluorescence area during the mean follow-up of 69.7 months. The mean thickness of the photoreceptor layer at fovea was 177 microm in eyes with AZOOR, which was significantly thinner than controls (193 microm, P = 0.049). Abnormal retinal laminations were found in 12 eyes and were located over areas of loss of the photoreceptors. The subfoveal choroidal thickness was 243 microm, which is normal. Fundus autofluorescence abnormalities in AZOOR showed distinct patterns of retinal pigment epithelial involvement, which may be progressive. Thinning of photoreceptor cell layer with loss of the outer segments and abnormal inner retinal lamination in the context of a normal choroid are commonly found in AZOOR.

Progressive Retinal Degeneration and Accumulation of Autofluorescent Lipopigments in Progranulin Deficient Mice

PubMed Central

Hafler, Brian P.; Klein, Zoe A.; Zhou, Z. Jimmy; Strittmatter, Stephen M.

2014-01-01

Prior investigations have shown that patients with neuronal ceroid lipofuscinosis (NCL) develop neurodegeneration characterized by vision loss, motor dysfunction, seizures, and often early death. Neuropathological analysis of patients with NCL shows accumulation of intracellular autofluorescent storage material, lipopigment, throughout neurons in the central nervous system including in the retina. A recent study of a sibling pair with adult onset NCL and retinal degeneration showed linkage to the region of the progranulin (GRN) locus and a homozygous mutation was demonstrated in GRN. In particular, the sibling pair with a mutation in GRN developed retinal degeneration and optic atrophy. This locus for this form of adult onset neuronal ceroid lipofuscinosis was designated neuronal ceroid lipofuscinosis-11 (CLN11). Based on these clinical observations, we wished to determine whether Grn-null mice develop accumulation of autofluorescent particles and retinal degeneration. Retinas of both wild-type and Progranulin deficient mice were examined by immunostaining and autofluorescence. Accumulation of autofluorescent material was present in Progranulin deficient mice at 12 months. Degeneration of multiple classes of neurons including photoreceptors and retinal ganglion cells was noted in mice at 12 and 18 months. Our data shows that Grn−/− mice develop degenerative pathology similar to features of human CLN11. PMID:25234724

A Biocompatible and Biodegradable Protein Hydrogel with Green and Red Autofluorescence: Preparation, Characterization and In Vivo Biodegradation Tracking and Modeling

PubMed Central

Ma, Xiaoyu; Sun, Xiangcheng; Hargrove, Derek; Chen, Jun; Song, Donghui; Dong, Qiuchen; Lu, Xiuling; Fan, Tai-Hsi; Fu, Youjun; Lei, Yu

2016-01-01

Because of its good biocompatibility and biodegradability, albumins such as bovine serum albumin (BSA) and human serum albumin (HSA) have found a wide range of biomedical applications. Herein, we report that glutaraldehyde cross-linked BSA (or HSA) forms a novel fluorescent biological hydrogel, exhibiting new green and red autofluorescence in vitro and in vivo without the use of any additional fluorescent labels. UV-vis spectra studies, in conjunction with the fluorescence spectra studies including emission, excitation and synchronous scans, indicated that three classes of fluorescent compounds are presumably formed during the gelation process. SEM, FTIR and mechanical tests were further employed to investigate the morphology, the specific chemical structures and the mechanical strength of the as-prepared autofluorescent hydrogel, respectively. Its biocompatibility and biodegradability were also demonstrated through extensive in vitro and in vivo studies. More interestingly, the strong red autofluorescence of the as-prepared hydrogel allows for conveniently and non-invasively tracking and modeling its in vivo degradation based on the time-dependent fluorescent images of mice. A mathematical model was proposed and was in good agreement with the experimental results. The developed facile strategy to prepare novel biocompatible and biodegradable autofluorescent protein hydrogels could significantly expand the scope of protein hydrogels in biomedical applications. PMID:26813916

Near-infrared autofluorescence induced by intraplaque hemorrhage and heme degradation as marker for high-risk atherosclerotic plaques.

PubMed

Htun, Nay Min; Chen, Yung Chih; Lim, Bock; Schiller, Tara; Maghzal, Ghassan J; Huang, Alex L; Elgass, Kirstin D; Rivera, Jennifer; Schneider, Hans G; Wood, Bayden R; Stocker, Roland; Peter, Karlheinz

2017-07-13

Atherosclerosis is a major cause of mortality and morbidity, which is mainly driven by complications such as myocardial infarction and stroke. These complications are caused by thrombotic arterial occlusion localized at the site of high-risk atherosclerotic plaques, of which early detection and therapeutic stabilization are urgently needed. Here we show that near-infrared autofluorescence is associated with the presence of intraplaque hemorrhage and heme degradation products, particularly bilirubin by using our recently created mouse model, which uniquely reflects plaque instability as seen in humans, and human carotid endarterectomy samples. Fluorescence emission computed tomography detecting near-infrared autofluorescence allows in vivo monitoring of intraplaque hemorrhage, establishing a preclinical technology to assess and monitor plaque instability and thereby test potential plaque-stabilizing drugs. We suggest that near-infrared autofluorescence imaging is a novel technology that allows identification of atherosclerotic plaques with intraplaque hemorrhage and ultimately holds promise for detection of high-risk plaques in patients.Atherosclerosis diagnosis relies primarily on imaging and early detection of high-risk atherosclerotic plaques is important for risk stratification of patients and stabilization therapies. Here Htun et al. demonstrate that vulnerable atherosclerotic plaques generate near-infrared autofluorescence that can be detected via emission computed tomography.

Fundus autofluorescence, optical coherence tomography, and electroretinogram findings in choroidal sclerosis.

PubMed

Hwang, John C; Kim, David Y; Chou, Chai Lin; Tsang, Stephen H

2010-01-01

The purpose of this study was to describe fundus autofluorescence (FAF), optical coherence tomography, and electroretinogram findings in choroidal sclerosis. This is a retrospective case series. Eight eyes of four patients with choroidal sclerosis were evaluated with FAF, optical coherence tomography, and electroretinogram testing. In all eight eyes, FAF imaging showed hypofluorescent placoid lesions corresponding to areas of chorioretinal atrophy seen on stereo biomicroscopy. Prominent hyperfluorescent linear markings underlying regions of atrophic disease were observed in all eyes, likely representative of normal choroidal vessel autofluorescence. In two eyes, FAF showed punctate hypofluorescent lesions in the fovea that were not visualized on biomicroscopy. In one eye, FAF identified a central island of preserved retinal pigment epithelium that was not realized on ophthalmoscopic examination. Optical coherence imaging was significant for loss of choroidal fine tubular structures, retinal pigment epithelium, and outer nuclear layer in regions of chorioretinal atrophy. Full-field electroretinogram testing showed generalized rod-cone dysfunction in all patients with a lower B- to A-wave ratio in two patients. Fundus autofluorescence and optical coherence tomography are nonin-vasive diagnostic adjuncts that can aid in the diagnosis of choroidal sclerosis. Fundus autofluorescence may be a more sensitive marker of disease extent and progression than clinical examination alone. Electroretinogram testing can result in an electronegative maximal response.

Ocular aberrations with ray tracing and Shack-Hartmann wave-front sensors: Does polarization play a role?

NASA Astrophysics Data System (ADS)

Marcos, Susana; Diaz-Santana, Luis; Llorente, Lourdes; Dainty, Chris

2002-06-01

Ocular aberrations were measured in 71 eyes by using two reflectometric aberrometers, employing laser ray tracing (LRT) (60 eyes) and a Shack-Hartmann wave-front sensor (S-H) (11 eyes). In both techniques a point source is imaged on the retina (through different pupil positions in the LRT or a single position in the S-H). The aberrations are estimated by measuring the deviations of the retinal spot from the reference as the pupil is sampled (in LRT) or the deviations of a wave front as it emerges from the eye by means of a lenslet array (in the S-H). In this paper we studied the effect of different polarization configurations in the aberration measurements, including linearly polarized light and circularly polarized light in the illuminating channel and sampling light in the crossed or parallel orientations. In addition, completely depolarized light in the imaging channel was obtained from retinal lipofuscin autofluorescence. The intensity distribution of the retinal spots as a function of entry (for LRT) or exit pupil (for S-H) depends on the polarization configuration. These intensity patterns show bright corners and a dark area at the pupil center for crossed polarization, an approximately Gaussian distribution for parallel polarization and a homogeneous distribution for the autofluorescence case. However, the measured aberrations are independent of the polarization states. These results indicate that the differences in retardation across the pupil imposed by corneal birefringence do not produce significant phase delays compared with those produced by aberrations, at least within the accuracy of these techniques. In addition, differences in the recorded aerial images due to changes in polarization do not affect the aberration measurements in these reflectometric aberrometers.

In vivo quantitative visualization of hypochlorous acid in the liver using a novel selective two-photon fluorescent probe

NASA Astrophysics Data System (ADS)

Wang, Haolu; Jayachandran, Aparna; Gravot, Germain; Liang, Xiaowen; Thorling, Camilla A.; Zhang, Run; Liu, Xin; Roberts, Michael S.

2016-11-01

Hypochlorous acid (HOCl) plays a vital role in physiological events and diseases. During hepatic ischemia-reperfusion (I/R) injury, HOCl is generated by neutrophils and diffuses into hepatocytes, causing oxidant stress-mediated injury. Although many probes have been developed to detect HOCl, most were difficult to be distinguished from endogenous fluorophores in intravital imaging and only can be employed under one-photon microscopy. A novel iridium(III) complex-based ferrocene dual-signaling chemosensor (Ir-Fc) was designed and synthesized. Ir-Fc exhibited a strong positive fluorescent response only in the presence of HOCl, whereas negligible fluorescent signals were observed upon the additions of other reactive oxygen/nitrogen species and metal ions. There was a good linear relationship between probe responsive fluorescent intensity and HOCl concentration. Ir-Fc was then intravenously injected into BALB/c mice at the final concentration of 50 μM and the mouse livers were imaged using multiphoton microscopy (MPM). In the I/R liver, reduced autofluorescence was detected by MPM, indicating the hepatocyte necrosis. Remarkable enhancement of red fluorescence was observed in hepatocytes with decreased autofluorescence, indicating the reaction of Ir-Fc with endogenous HOCl molecules. The cellular concentration of HOCl was first calculated based on the intensity of MPM images. No obvious toxic effects were observed in histological examination of major organs after Ir-Fc injection. In summary, Ir-Fc has low cytotoxicity, high specificity to HOCl, and rapid "off-on" fluorescence. It is suitable for dynamic quantitatively monitoring HOCl generation using MPM at the cellular level. This technique can be readily extended to examination of liver diseases and injury.

Synchrotron Time-Lapse Imaging of Lignocellulosic Biomass Hydrolysis: Tracking Enzyme Localization by Protein Autofluorescence and Biochemical Modification of Cell Walls by Microfluidic Infrared Microspectroscopy

PubMed Central

Devaux, Marie-Françoise; Jamme, Frédéric; André, William; Bouchet, Brigitte; Alvarado, Camille; Durand, Sylvie; Robert, Paul; Saulnier, Luc; Bonnin, Estelle; Guillon, Fabienne

2018-01-01

Tracking enzyme localization and following the local biochemical modification of the substrate should help explain the recalcitrance of lignocellulosic plant cell walls to enzymatic degradation. Time-lapse studies using conventional imaging require enzyme labeling and following the biochemical modifications of biopolymers found in plant cell walls, which cannot be easily achieved. In the present work, synchrotron facilities have been used to image the enzymatic degradation of lignocellulosic biomass without labeling the enzyme or the cell walls. Multichannel autofluorescence imaging of the protein and phenolic compounds after excitation at 275 nm highlighted the presence or absence of enzymes on cell walls and made it possible to track them during the reaction. Image analysis was used to quantify the fluorescence intensity variations. Consistent variations in the enzyme concentration were found locally for cell cavities and their surrounding cell walls. Microfluidic FT-IR microspectroscopy allowed for time-lapse tracking of local changes in the polysaccharides in cell walls during degradation. Hemicellulose degradation was found to occur prior to cellulose degradation using a Celluclast® preparation. Combining the fluorescence and FT-IR information yielded the conclusion that enzymes did not bind to lignified cell walls, which were consequently not degraded. Fluorescence multiscale imaging and FT-IR microspectroscopy showed an unexpected variability both in the initial biochemical composition and the degradation pattern, highlighting micro-domains in the cell wall of a given cell. Fluorescence intensity quantification showed that the enzymes were not evenly distributed, and their amount increased progressively on degradable cell walls. During degradation, adjacent cells were separated and the cell wall fragmented until complete degradation. PMID:29515611

ACUTE ZONAL OCCULT OUTER RETINOPATHY: Structural and Functional Analysis Across the Transition Zone Between Healthy and Diseased Retina.

PubMed

Duncker, Tobias; Lee, Winston; Jiang, Fan; Ramachandran, Rithambara; Hood, Donald C; Tsang, Stephen H; Sparrow, Janet R; Greenstein, Vivienne C

2018-01-01

To assess structure and function across the transition zone (TZ) between relatively healthy and diseased retina in acute zonal occult outer retinopathy. Six patients (6 eyes; age 22-71 years) with acute zonal occult outer retinopathy were studied. Spectral-domain optical coherence tomography, fundus autofluorescence, near-infrared reflectance, color fundus photography, and fundus perimetry were performed and images were registered to each other. The retinal layers of the spectral-domain optical coherence tomography scans were segmented and the thicknesses of two outer retinal layers, that is, the total receptor and outer segment plus layers, and the retinal nerve fiber layer were measured. All eyes showed a TZ on multimodal imaging. On spectral-domain optical coherence tomography, the TZ was in the nasal retina at varying distances from the fovea. For all eyes, it was associated with loss of the ellipsoid zone band, significant thinning of the two outer retinal layers, and in three eyes with thickening of the retinal nerve fiber layer. On fundus autofluorescence, all eyes had a clearly demarcated peripapillary area of abnormal fundus autofluorescence delimited by a border of high autofluorescence; the latter was associated with loss of the ellipsoid zone band and with a change from relatively normal to markedly decreased or nonrecordable visual sensitivity on fundus perimetry. The results of multimodal imaging clarified the TZ in acute zonal occult outer retinopathy. The TZ was outlined by a distinct high autofluorescence border that correlated with loss of the ellipsoid zone band on spectral-domain optical coherence tomography. However, in fundus areas that seemed healthy on fundus autofluorescence, thinning of the outer retinal layers and thickening of the retinal nerve fiber layer were observed near the TZ. The TZ was also characterized by a decrease in visual sensitivity.

Diabetic retinal pigment epitheliopathy: fundus autofluorescence and spectral-domain optical coherence tomography findings.

PubMed

Kang, Eui Chun; Seo, Yuri; Byeon, Suk Ho

2016-10-01

To describe the characteristics of an unfamiliar disease entity, diabetic retinal pigment epitheliopathy (DRPE), using fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (SD-OCT). This retrospective study included 17 eyes from 10 proliferative diabetic retinopathy (PDR) patients with granular hypo-autofluorescence and/or variable hyper-autofluorescence on FAF (DRPE group) and 17 eyes from 10 age- and sex-matched PDR patients without abnormal autofluorescence (PDR group). Eyes with diabetic macular edema were excluded. Visual acuity (VA), retinal thickness (RT), and choroidal thickness (CT) were compared between the groups. Eyes in the DRPE group had worse logMAR VA than eyes in the PDR group (0.369 ± 0.266 vs. 0.185 ± 0.119; P = 0.026). The thickness of the retinal pigment epithelium plus the inner segment/outer segment of the photoreceptors was reduced to a greater degree in the DRPE group than the PDR group (P < 0.001). Moreover, the thickness of the outer nuclear layer plus the outer plexiform layer was thinner in the DRPE group than in the PDR (P = 0.013). However, the thickness of the inner retina showed no differences between the two groups. CT was significantly thicker in the DRPE group than in the PDR group (329.00 ± 33.76 vs. 225.62 ± 37.47 μm; P < 0.001). Eyes with DRPE showed reduced VA, a thinner outer retina, and thicker choroid in comparison with eyes with PDR. Alterations of autofluorescence on FAF and changes in the outer retinal thickness and CT on SD-OCT can be helpful for differentiating DRPE in patients with PDR.

COMPARISON OF MANUAL AND SEMIAUTOMATED FUNDUS AUTOFLUORESCENCE ANALYSIS OF MACULAR ATROPHY IN STARGARDT DISEASE PHENOTYPE.

PubMed

Kuehlewein, Laura; Hariri, Amir H; Ho, Alexander; Dustin, Laurie; Wolfson, Yulia; Strauss, Rupert W; Scholl, Hendrik P N; Sadda, SriniVas R

2016-06-01

To evaluate manual and semiautomated grading techniques for assessing decreased fundus autofluorescence (DAF) in patients with Stargardt disease phenotype. Certified reading center graders performed manual and semiautomated (region finder-based) grading of confocal scanning laser ophthalmoscopy (cSLO) fundus autofluorescence (FAF) images for 41 eyes of 22 patients. Lesion types were defined based on the black level and sharpness of the border: definite decreased autofluorescence (DDAF), well, and poorly demarcated questionably decreased autofluorescence (WDQDAF, PDQDAF). Agreement in grading between the two methods and inter- and intra-grader agreement was assessed by kappa coefficients (κ) and intraclass correlation coefficients (ICC). The mean ± standard deviation (SD) area was 3.07 ± 3.02 mm for DDAF (n = 31), 1.53 ± 1.52 mm for WDQDAF (n = 9), and 6.94 ± 10.06 mm for PDQDAF (n = 17). The mean ± SD absolute difference in area between manual and semiautomated grading was 0.26 ± 0.28 mm for DDAF, 0.20 ± 0.26 mm for WDQDAF, and 4.05 ± 8.32 mm for PDQDAF. The ICC (95% confidence interval) for method comparison was 0.992 (0.984-0.996) for DDAF, 0.976 (0.922-0.993) for WDQDAF, and 0.648 (0.306-0.842) for PDQDAF. Inter- and intra-grader agreement in manual and semiautomated quantitative grading was better for DDAF (0.981-0.996) and WDQDAF (0.995-0.999) than for PDQDAF (0.715-0.993). Manual and semiautomated grading methods showed similar levels of reproducibility for assessing areas of decreased autofluorescence in patients with Stargardt disease phenotype. Excellent agreement and reproducibility were observed for well demarcated lesions.

Association between fundus autofluorescence and visual outcome in surgically closed macular holes.

PubMed

Lee, Young Seob; Yu, Seung-Young; Cho, Nam Suk; Kim, Moo Sang; Kim, Young Gyun; Kim, Eung Suk; Kwak, Hyung Woo

2013-06-01

To investigate the association between fundus autofluorescence (FAF) and visual acuity, recovery of foveal microstructure, and FAF in surgically closed macular holes. Twenty-six eyes with surgically closed macular hole were classified into two groups based on foveal FAF: normal autofluorescence (NAF) or increased autofluorescence (IAF). The association between foveal FAF and visual acuity was analyzed. In addition, we examined the relationship between recovery of the foveal microstructure assessed by spectral domain optical coherence tomography and FAF after macular hole surgery. At 1 month and 6 months after surgery, there were 9 NAF eyes and 17 IAF eyes. There were no differences between NAF and IAF eyes at 1 month and 6 months after surgery. Preoperative best-corrected visual acuity (logarithm of the minimum angle of resolution) did not differ between groups. Best-corrected visual acuity was significantly higher in the NAF group than in the IAF group at 1 month postoperatively (0.59 ± 0.34 vs. 0.91 ± 0.36, P = 0.044) and tended to be higher at 6 months (0.37 ± 0.38 vs. 0.69 ± 0.53, P = 0.126). Restoration of photoreceptor external limiting membrane differed significantly in 8 NAF eyes (89%) and 4 IAF eyes (24%) at postoperation 1 month (P = 0.001). After 6 months, external limiting membrane was restored in all 9 NAF eyes (100%) and in only 11 IAF eyes (65%) (P = 0.042). Fundus autofluorescence findings observed in surgically closed macular holes correlated with visual improvement and photoreceptor status. Eyes with visual improvement had restoration of normal foveal autofluorescence and retinal microstructure, whereas eyes with persistent foveal hyperautofluorescence did not achieve complete restoration of the retinal microstructure, and visual improvement was not as significant.

Adaptive optics fundus images of cone photoreceptors in the macula of patients with retinitis pigmentosa.

PubMed

Tojo, Naoki; Nakamura, Tomoko; Fuchizawa, Chiharu; Oiwake, Toshihiko; Hayashi, Atsushi

2013-01-01

The purpose of this study was to examine cone photoreceptors in the macula of patients with retinitis pigmentosa using an adaptive optics fundus camera and to investigate any correlations between cone photoreceptor density and findings on optical coherence tomography and fundus autofluorescence. We examined two patients with typical retinitis pigmentosa who underwent ophthalmological examination, including measurement of visual acuity, and gathering of electroretinographic, optical coherence tomographic, fundus autofluorescent, and adaptive optics fundus images. The cone photoreceptors in the adaptive optics images of the two patients with retinitis pigmentosa and five healthy subjects were analyzed. An abnormal parafoveal ring of high-density fundus autofluorescence was observed in the macula in both patients. The border of the ring corresponded to the border of the external limiting membrane and the inner segment and outer segment line in the optical coherence tomographic images. Cone photoreceptors at the abnormal parafoveal ring were blurred and decreased in the adaptive optics images. The blurred area corresponded to the abnormal parafoveal ring in the fundus autofluorescence images. Cone densities were low at the blurred areas and at the nasal and temporal retina along a line from the fovea compared with those of healthy controls. The results for cone spacing and Voronoi domains in the macula corresponded with those for the cone densities. Cone densities were heavily decreased in the macula, especially at the parafoveal ring on high-density fundus autofluorescence in both patients with retinitis pigmentosa. Adaptive optics images enabled us to observe in vivo changes in the cone photoreceptors of patients with retinitis pigmentosa, which corresponded to changes in the optical coherence tomographic and fundus autofluorescence images.

Quantitative fundus autofluorescence in recessive Stargardt disease.

PubMed

Burke, Tomas R; Duncker, Tobias; Woods, Russell L; Greenberg, Jonathan P; Zernant, Jana; Tsang, Stephen H; Smith, R Theodore; Allikmets, Rando; Sparrow, Janet R; Delori, François C

2014-05-01

To quantify fundus autofluorescence (qAF) in patients with recessive Stargardt disease (STGD1). A total of 42 STGD1 patients (ages: 7-52 years) with at least one confirmed disease-associated ABCA4 mutation were studied. Fundus AF images (488-nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for variable laser power and detector sensitivity. The gray levels (GLs) of each image were calibrated to the reference, zero GL, magnification, and normative optical media density to yield qAF. Texture factor (TF) was calculated to characterize inhomogeneities in the AF image and patients were assigned to the phenotypes of Fishman I through III. Quantified fundus autofluorescence in 36 of 42 patients and TF in 27 of 42 patients were above normal limits for age. Young patients exhibited the relatively highest qAF, with levels up to 8-fold higher than healthy eyes. Quantified fundus autofluorescence and TF were higher in Fishman II and III than Fishman I, who had higher qAF and TF than healthy eyes. Patients carrying the G1916E mutation had lower qAF and TF than most other patients, even in the presence of a second allele associated with severe disease. Quantified fundus autofluorescence is an indirect approach to measuring RPE lipofuscin in vivo. We report that ABCA4 mutations cause significantly elevated qAF, consistent with previous reports indicating that increased RPE lipofuscin is a hallmark of STGD1. Even when qualitative differences in fundus AF images are not evident, qAF can elucidate phenotypic variation. Quantified fundus autofluorescence will serve to establish genotype-phenotype correlations and as an outcome measure in clinical trials.

Quantitative Fundus Autofluorescence in Recessive Stargardt Disease

PubMed Central

Burke, Tomas R.; Duncker, Tobias; Woods, Russell L.; Greenberg, Jonathan P.; Zernant, Jana; Tsang, Stephen H.; Smith, R. Theodore; Allikmets, Rando; Sparrow, Janet R.; Delori, François C.

2014-01-01

Purpose. To quantify fundus autofluorescence (qAF) in patients with recessive Stargardt disease (STGD1). Methods. A total of 42 STGD1 patients (ages: 7–52 years) with at least one confirmed disease-associated ABCA4 mutation were studied. Fundus AF images (488-nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for variable laser power and detector sensitivity. The gray levels (GLs) of each image were calibrated to the reference, zero GL, magnification, and normative optical media density to yield qAF. Texture factor (TF) was calculated to characterize inhomogeneities in the AF image and patients were assigned to the phenotypes of Fishman I through III. Results. Quantified fundus autofluorescence in 36 of 42 patients and TF in 27 of 42 patients were above normal limits for age. Young patients exhibited the relatively highest qAF, with levels up to 8-fold higher than healthy eyes. Quantified fundus autofluorescence and TF were higher in Fishman II and III than Fishman I, who had higher qAF and TF than healthy eyes. Patients carrying the G1916E mutation had lower qAF and TF than most other patients, even in the presence of a second allele associated with severe disease. Conclusions. Quantified fundus autofluorescence is an indirect approach to measuring RPE lipofuscin in vivo. We report that ABCA4 mutations cause significantly elevated qAF, consistent with previous reports indicating that increased RPE lipofuscin is a hallmark of STGD1. Even when qualitative differences in fundus AF images are not evident, qAF can elucidate phenotypic variation. Quantified fundus autofluorescence will serve to establish genotype-phenotype correlations and as an outcome measure in clinical trials. PMID:24677105

Optical metrics of the extracellular matrix predict compositional and mechanical changes after myocardial infarction

NASA Astrophysics Data System (ADS)

Quinn, Kyle P.; Sullivan, Kelly E.; Liu, Zhiyi; Ballard, Zachary; Siokatas, Christos; Georgakoudi, Irene; Black, Lauren D.

2016-11-01

Understanding the organization and mechanical function of the extracellular matrix (ECM) is critical for the development of therapeutic strategies that regulate wound healing following disease or injury. However, these relationships are challenging to elucidate during remodeling following myocardial infarction (MI) due to rapid changes in cellularity and an inability to characterize both ECM microstructure and function non-destructively. In this study, we overcome those challenges through whole organ decellularization and non-linear optical microscopy to directly relate the microstructure and mechanical properties of myocardial ECM. We non-destructively quantify collagen organization, content, and cross-linking within decellularized healthy and infarcted myocardium using second harmonic generation (SHG) and two photon excited autofluorescence. Tensile mechanical testing and compositional analysis reveal that the cumulative SHG intensity within each image volume and the average collagen autofluorescence are significantly correlated with collagen content and elastic modulus of the ECM, respectively. Compared to healthy ECM, infarcted tissues demonstrate a significant increase in collagen content and fiber alignment, and a decrease in cross-linking and elastic modulus. These findings indicate that cross-linking plays a key role in stiffness at the collagen fiber level following infarction, and highlight how this non-destructive approach to assessing remodeling can be used to understand ECM structure-function relationships.

Research on optical properties of dental enamel for early caries diagnostics using a He-Ne laser

NASA Astrophysics Data System (ADS)

Tang, Jing; Liu, Li; Li, Song-zhan

2008-12-01

A new and non-invasive method adapted for optical diagnosis of early caries is proposed by researching on the interaction mechanism of laser with dental tissue and relations of remitted light with optical properties of the tissue. This method is based on simultaneous analyses of the following parameters: probing radiation, backscattering and auto-fluorescence. Investigation was performed on 104 dental samples in vitro by using He-Ne laser (λ=632.8nm, 2.0+/-0.1mW) as the probing. Spectrums of all samples were obtained. Characteristic spectrums of dental caries in various stages (intact, initial, moderate and deep) were given. Using the back-reflected light to normalize the intensity of back-scattering and fluorescence, a quantitative diagnosis standard for different stages of caries is proposed. In order to verify the test, comparison research was conducted among artificial caries, morphological damaged enamel, dental calculus and intact tooth. Results show that variations in backscattering characteristic changes in bio-tissue morphological and the quantity of auto-fluorescence is correlated with concentration of anaerobic microflora in hearth of caries lesion. This method poses a high potential of diagnosing various stages of dental caries, and is more reliability to detect early caries, surface damage of health enamel and dental calculus.

An Infrared Actin Probe for Deep-Cell Electroporation-Based Single-Molecule Speckle (eSiMS) Microscopy

PubMed Central

Yamashiro, Sawako; Watanabe, Naoki

2017-01-01

Single-molecule speckle (SiMS) microscopy is a powerful method to directly elucidate biochemical reactions in live cells. However, since the signal from an individual fluorophore is extremely faint, the observation area by epi-fluorescence microscopy is restricted to the thin cell periphery to reduce autofluorescence, or only molecules near the plasma membrane are visualized by total internal reflection fluorescence (TIRF) microscopy. Here, we introduce a new actin probe labeled with near infrared (NIR) emissive CF680R dye for easy-to-use, electroporation-based SiMS microscopy (eSiMS) for deep-cell observation. CF680R-labeled actin (CF680R-actin) incorporated into actin structures and showed excellent brightness and photostability suitable for single-molecule imaging. Importantly, the intensity of autofluorescence with respect to SiMS brightness was reduced to approximately 13% compared to DyLight 550-labeled actin (DL550-actin). CF680R-actin enabled the monitoring of actin SiMS in actomyosin bundles associated with adherens junctions (AJs) located at 3.5–4 µm above the basal surfaces of epithelial monolayers. These favorable properties of CF680R-actin extend the application of eSiMS to actin turnover and flow analyses in deep cellular structures. PMID:28671584

A new method using multiphoton imaging and morphometric analysis for differentiating chromophobe renal cell carcinoma and oncocytoma kidney tumors

NASA Astrophysics Data System (ADS)

Wu, Binlin; Mukherjee, Sushmita; Jain, Manu

2016-03-01

Distinguishing chromophobe renal cell carcinoma (chRCC) from oncocytoma on hematoxylin and eosin images may be difficult and require time-consuming ancillary procedures. Multiphoton microscopy (MPM), an optical imaging modality, was used to rapidly generate sub-cellular histological resolution images from formalin-fixed unstained tissue sections from chRCC and oncocytoma.Tissues were excited using 780nm wavelength and emission signals (including second harmonic generation and autofluorescence) were collected in different channels between 390 nm and 650 nm. Granular structure in the cell cytoplasm was observed in both chRCC and oncocytoma. Quantitative morphometric analysis was conducted to distinguish chRCC and oncocytoma. To perform the analysis, cytoplasm and granules in tumor cells were segmented from the images. Their area and fluorescence intensity were found in different channels. Multiple features were measured to quantify the morphological and fluorescence properties. Linear support vector machine (SVM) was used for classification. Re-substitution validation, cross validation and receiver operating characteristic (ROC) curve were implemented to evaluate the efficacy of the SVM classifier. A wrapper feature algorithm was used to select the optimal features which provided the best predictive performance in separating the two tissue types (classes). Statistical measures such as sensitivity, specificity, accuracy and area under curve (AUC) of ROC were calculated to evaluate the efficacy of the classification. Over 80% accuracy was achieved as the predictive performance. This method, if validated on a larger and more diverse sample set, may serve as an automated rapid diagnostic tool to differentiate between chRCC and oncocytoma. An advantage of such automated methods are that they are free from investigator bias and variability.

Study on the autofluorescence profiles of iris pigment epithelium and retinal pigment epithetlium

NASA Astrophysics Data System (ADS)

Xu, Gaixia; Qu, Junle; Chen, Danni; Sun, Yiwen; Zhao, Lingling; Lin, Ziyang; Ding, Zhihua; Niu, Hanben

2007-05-01

Transplantation technique of retinal pigment epithelium has been noticeable in recent years and gradually put into clinical practice in treatment of retinal degenerative diseases. Generally, immunological, histochemical, and physical methods are used to study the iris pigment epithelium (IPE) and retinal pigment epithelium (RPE) cells, which need complex sample preparation. In this paper, we provided a simple autofluorescence microscopy to investigate the fresh porcine IPE and RPE cells without any pretreatment. The results showed that the morphology and size of both were similar, round and about 15 μm. The main flourophore in both cells was similar, i.e. lipofuscin. In additional, the autofluorescence spectrum of RPE shifted blue after light-induced damage by laser illuminating. Because it was easier for IPE to be damaged by laser than for RPE, and the power of one scanning operation to get a full image was strong enough to damage IPE sample, we hadn't get any satisfied autofluorescence spectrum of IPE.

Autofluorescence and spectral domain OCT findings in Alport syndrome.

PubMed

Randhawa, Sandeep; Fu, Arthur D; Lujan, Brandon J; McDonald, H Richard; Jumper, J Michael

2013-01-01

The purpose of this study was to report novel autofluorescence and spectral domain optic coherence tomography findings in a case of Alport syndrome. Case report and literature review. A 30-year-old woman with a history of Alport syndrome presented with a full-thickness macular hole in her right eye and evidence of vitreofoveal traction in her asymptomatic left eye. Both eyes had temporal macular thinning. She had anterior lenticonus and perimacular flecks characteristic of Alport syndrome. In addition, fundus autofluorescence revealed an interesting pattern of splotchy hypoautofluorescence in the periphery (in the absence of any peripheral retinopathy on examination), which has not been described previously. Macular hole in Alport syndrome results from basement membrane weakness and an abnormal vitreoretinal interface. Although this makes surgery in these cases challenging, careful separation of the posterior hyaloid and internal limiting membrane peeling with fluid gas exchange can lead to successful closure. Alport syndrome can also cause abnormalities in the retinal pigment epithelium/Bruch membrane leading to abnormal autofluorescence.

2-photon laser scanning microscopy on native human cartilage

NASA Astrophysics Data System (ADS)

Martini, Joerg; Toensing, Katja; Dickob, Michael; Anselmetti, Dario

2005-08-01

Native hyaline cartilage from a human knee joint was directly investigated with laser scanning microscopy via 2-photon autofluorescence excitation with no additional staining or labelling protocols in a nondestructive and sterile manner. Using a femtosecond, near-infrared (NIR) Ti:Sa laser for 2-photon excitation and a dedicated NIR long distance objective, autofluorescence imaging and measurements of the extracellular matrix (ECM) tissue with incorporated chondrocytes were possible with a penetration depth of up to 460 μm inside the sample. Via spectral autofluorescence separation these experiments allowed the discrimination of chondrocytes from the ECM and therefore an estimate of chondrocytic cell density within the cartilage tissue to approximately 0.2-2•107cm3. Furthermore, a comparison of the relative autofluorescence signals between nonarthritic and arthritic cartilage tissue exhibited distinct differences in tissue morphology. As these morphological findings are in keeping with the macroscopic diagnosis, our measurement has the potential of being used in future diagnostic applications.

Evaluation of Acute Kidney Injury and Mortality After Intensive Blood Pressure Control in Patients With Intracerebral Hemorrhage.

PubMed

Burgess, L Goodwin; Goyal, Nitin; Jones, G Morgan; Khorchid, Yasser; Kerro, Ali; Chapple, Kristina; Tsivgoulis, Georgios; Alexandrov, Andrei V; Chang, Jason J

2018-04-13

We sought to assess the risk of acute kidney injury (AKI) and mortality associated with intensive systolic blood pressure reduction in acute intracerebral hemorrhage. Patients with acute intracerebral hemorrhage had spontaneous cause and symptom onset within 24 hours. We excluded patients with structural causes, coagulopathy, thrombocytopenia, and preexisting end-stage renal disease. We defined AKI using the Acute Kidney Injury Network criteria. Chronic kidney disease status was included in risk stratification and was defined by Kidney Disease Outcomes Quality Initiative staging. Maximum systolic blood pressure reduction was defined over a 12-hour period and dichotomized using receiver operating characteristic curve analysis. Descriptive statistics were done using independent sample t tests, χ 2 tests, and Mann-Whitney U tests, whereas multivariable logistic regression analysis was used to evaluate for predictors for AKI and mortality. A total of 448 patients with intracerebral hemorrhage met inclusion criteria. Maximum systolic blood pressure reduction was dichotomized to 90 mm Hg and found to increase the risk of AKI in patients with normal renal function (odds ratio, 2.1; 95% confidence interval, 1.19-3.62; P =0.010) and chronic kidney disease (odds ratio, 3.91; 95% confidence interval, 1.26-12.15; P =0.019). The risk of AKI was not significantly different in normal renal function versus chronic kidney disease groups when adjusted for demographics, presentation characteristics, and medications associated with AKI. AKI positively predicted mortality for patients with normal renal function (odds ratio, 2.41; 95% confidence interval, 1.11-5.22; P =0.026) but not for patients with chronic kidney disease (odds ratio, 3.13; 95% confidence interval, 0.65-15.01; P =0.154). These results indicate that intensive systolic blood pressure reduction with a threshold >90 mm Hg in patients with acute intracerebral hemorrhage may be an independent predictor for AKI. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

High Intensity Interval Training Favourably Affects Angiotensinogen mRNA Expression and Markers of Cardiorenal Health in a Rat Model of Early-Stage Chronic Kidney Disease.

PubMed

Tucker, Patrick S; Scanlan, Aaron T; Dalbo, Vincent J

2015-01-01

The majority of CKD-related complications stem from cardiovascular pathologies such as hypertension. To help reduce cardiovascular complications, aerobic exercise is often prescribed. Emerging evidence suggests high intensity interval training (HIIT) may be more beneficial than traditional aerobic exercise. However, appraisals of varying forms of aerobic exercise, along with descriptions of mechanisms responsible for health-related improvements, are lacking. This study examined the effects of 8 weeks of HIIT (85% VO2max), versus low intensity aerobic exercise (LIT; 45-50% VO2max) and sedentary behaviour (SED), in an animal model of early-stage CKD. Tissue-specific mRNA expression of RAAS-related genes and CKD-related clinical markers were examined. Compared to SED, HIIT resulted in increased plasma albumin (p = 0.001), reduced remnant kidney weight (p = 0.028), and reduced kidney weight-body weight ratios (p = 0.045). Compared to LIT, HIIT resulted in reduced Agt mRNA expression (p = 0.035), reduced plasma LDL (p = 0.001), triglycerides (p = 0.029), and total cholesterol (p = 0.002), increased plasma albumin (p = 0.047), reduced remnant kidney weight (p = 0.005), and reduced kidney weight-body weight ratios (p = 0.048). These results suggest HIIT is a more potent regulator of several markers that describe and influence health in CKD.

High Intensity Interval Training Favourably Affects Angiotensinogen mRNA Expression and Markers of Cardiorenal Health in a Rat Model of Early-Stage Chronic Kidney Disease

PubMed Central

Tucker, Patrick S.; Scanlan, Aaron T.; Dalbo, Vincent J.

2015-01-01

The majority of CKD-related complications stem from cardiovascular pathologies such as hypertension. To help reduce cardiovascular complications, aerobic exercise is often prescribed. Emerging evidence suggests high intensity interval training (HIIT) may be more beneficial than traditional aerobic exercise. However, appraisals of varying forms of aerobic exercise, along with descriptions of mechanisms responsible for health-related improvements, are lacking. This study examined the effects of 8 weeks of HIIT (85% VO2max), versus low intensity aerobic exercise (LIT; 45–50% VO2max) and sedentary behaviour (SED), in an animal model of early-stage CKD. Tissue-specific mRNA expression of RAAS-related genes and CKD-related clinical markers were examined. Compared to SED, HIIT resulted in increased plasma albumin (p = 0.001), reduced remnant kidney weight (p = 0.028), and reduced kidney weight-body weight ratios (p = 0.045). Compared to LIT, HIIT resulted in reduced Agt mRNA expression (p = 0.035), reduced plasma LDL (p = 0.001), triglycerides (p = 0.029), and total cholesterol (p = 0.002), increased plasma albumin (p = 0.047), reduced remnant kidney weight (p = 0.005), and reduced kidney weight-body weight ratios (p = 0.048). These results suggest HIIT is a more potent regulator of several markers that describe and influence health in CKD. PMID:26090382

Ocular autofluorescence in diabetes mellitus. A review.

PubMed

Calvo-Maroto, Ana M; Perez-Cambrodi, Rafael J; Garcia-Lazaro, Santiago; Ferrer-Blasco, Teresa; Cerviño, Alejandro

2016-09-01

Diabetes mellitus is a metabolic disease with a considerable impact on healthcare owing to its increased prevalence and high mortality rate. Structural, morphological, and physiological changes in each of the ocular components have been described in detail. Autofluorescence has been described as a good indicator of metabolic activity. The aim of the present review is to provide an overview of ocular endogenous fluorophores in the cornea, the crystalline lens, and the retinal pigment epithelium, the effects of diabetes mellitus and therefore the potential of autofluorescence assessment for screening and monitoring changes in diabetic patients. © 2016 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

Real-Time In Vivo Imaging of Butterfly Wing Development: Revealing the Cellular Dynamics of the Pupal Wing Tissue

PubMed Central

Iwata, Masaki; Ohno, Yoshikazu; Otaki, Joji M.

2014-01-01

Butterfly wings are covered with regularly arranged single-colored scales that are formed at the pupal stage. Understanding pupal wing development is therefore crucial to understand wing color pattern formation. Here, we successfully employed real-time in vivo imaging techniques to observe pupal hindwing development over time in the blue pansy butterfly, Junonia orithya. A transparent sheet of epithelial cells that were not yet regularly arranged was observed immediately after pupation. Bright-field imaging and autofluorescent imaging revealed free-moving hemocytes and tracheal branches of a crinoid-like structure underneath the epithelium. The wing tissue gradually became gray-white, epithelial cells were arranged regularly, and hemocytes disappeared, except in the bordering lacuna, after which scales grew. The dynamics of the epithelial cells and scale growth were also confirmed by fluorescent imaging. Fluorescent in vivo staining further revealed that these cells harbored many mitochondria at the surface of the epithelium. Organizing centers for the border symmetry system were apparent immediately after pupation, exhibiting a relatively dark optical character following treatment with fluorescent dyes, as well as in autofluorescent images. The wing tissue exhibited slow and low-frequency contraction pulses with a cycle of approximately 10 to 20 minutes, mainly occurring at 2 to 3 days postpupation. The pulses gradually became slower and weaker and eventually stopped. The wing tissue area became larger after contraction, which also coincided with an increase in the autofluorescence intensity that might have been caused by scale growth. Examination of the pattern of color development revealed that the black pigment was first deposited in patches in the central areas of an eyespot black ring and a parafocal element. These results of live in vivo imaging that covered wide wing area for a long time can serve as a foundation for studying the cellular dynamics of living wing tissues in butterflies. PMID:24586829

Real-time in vivo imaging of butterfly wing development: revealing the cellular dynamics of the pupal wing tissue.

PubMed

Iwata, Masaki; Ohno, Yoshikazu; Otaki, Joji M

2014-01-01

Butterfly wings are covered with regularly arranged single-colored scales that are formed at the pupal stage. Understanding pupal wing development is therefore crucial to understand wing color pattern formation. Here, we successfully employed real-time in vivo imaging techniques to observe pupal hindwing development over time in the blue pansy butterfly, Junonia orithya. A transparent sheet of epithelial cells that were not yet regularly arranged was observed immediately after pupation. Bright-field imaging and autofluorescent imaging revealed free-moving hemocytes and tracheal branches of a crinoid-like structure underneath the epithelium. The wing tissue gradually became gray-white, epithelial cells were arranged regularly, and hemocytes disappeared, except in the bordering lacuna, after which scales grew. The dynamics of the epithelial cells and scale growth were also confirmed by fluorescent imaging. Fluorescent in vivo staining further revealed that these cells harbored many mitochondria at the surface of the epithelium. Organizing centers for the border symmetry system were apparent immediately after pupation, exhibiting a relatively dark optical character following treatment with fluorescent dyes, as well as in autofluorescent images. The wing tissue exhibited slow and low-frequency contraction pulses with a cycle of approximately 10 to 20 minutes, mainly occurring at 2 to 3 days postpupation. The pulses gradually became slower and weaker and eventually stopped. The wing tissue area became larger after contraction, which also coincided with an increase in the autofluorescence intensity that might have been caused by scale growth. Examination of the pattern of color development revealed that the black pigment was first deposited in patches in the central areas of an eyespot black ring and a parafocal element. These results of live in vivo imaging that covered wide wing area for a long time can serve as a foundation for studying the cellular dynamics of living wing tissues in butterflies.

Intensive Hemodialysis and Mortality Risk in Australian and New Zealand Populations.

PubMed

Marshall, Mark R; Polkinghorne, Kevan R; Kerr, Peter G; Hawley, Carmel M; Agar, John W M; McDonald, Stephen P

2016-04-01

Intensive hemodialysis (HD) is characterized by increased frequency and/or session length compared to conventional HD. Previous analyses from Australia and New Zealand did not suggest benefit with intensive HD, although recent research suggests that relationships have changed. We present updated analyses. Observational cohort study using marginal structural modeling to adjust for changes in renal replacement modality and time-varying medical comorbid conditions. Adults initiating renal replacement therapy since March 31, 1996, followed up through December 31, 2012; this analysis included 40,842 patients over 2,187,689 patient-months. Time-varying renal replacement modality: conventional facility HD (≤3 times per week, ≤6 hours per session), quasi-intensive facility HD (between conventional and intensive), intensive facility HD (≥5 times per week, any hours per session), conventional home HD, quasi-intensive home HD, intensive home HD, peritoneal dialysis, deceased donor kidney transplantation, and living donor kidney transplantation. Patient mortality, with a 3-month lag in primary analyses and 6- and 12-month lags in sensitivity analyses. Conventional facility HD was the reference group. Conventional home HD had a similar mortality risk. For quasi-intensive home HD, mortality risk was lower (HR, 0.56; 95% CI, 0.44-0.73). For intensive home HD, mortality risk was nonsignificantly lower in primary analyses and significantly lower using a 6-month lag (HR, 0.41; 95% CI, 0.20-0.85), but not using a 12-month lag. For quasi-intensive facility HD, mortality risk was nonsignificantly lower in primary analyses, although significantly lower using 6- (HR, 0.41; 95% CI, 0.20-0.85) and 12-month lags (HR, 0.59; 95% CI, 0.44-0.80). Mortality risk was similar between intensive and conventional facility HD. For peritoneal dialysis, mortality risk was greater than for conventional facility HD (HR, 1.07; 95% CI, 1.03-1.12). Kidney transplantation had the lowest mortality risk. Potential residual confounding from limited collection of comorbid condition, socioeconomic, and medication data. There is an emerging HD dose-effect in Australia and New Zealand, with lower mortality risks associated with some of the more intensive HD regimens in these countries. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Near-infrared spectroscopic tissue imaging for medical applications

DOEpatents

Demos,; Stavros, Staggs [Livermore, CA; Michael, C [Tracy, CA

2006-03-21

Near infrared imaging using elastic light scattering and tissue autofluorescence are explored for medical applications. The approach involves imaging using cross-polarized elastic light scattering and tissue autofluorescence in the Near Infra-Red (NIR) coupled with image processing and inter-image operations to differentiate human tissue components.

Near-infrared spectroscopic tissue imaging for medical applications

DOEpatents

Demos, Stavros [Livermore, CA; Staggs, Michael C [Tracy, CA

2006-12-12

Near infrared imaging using elastic light scattering and tissue autofluorescence are explored for medical applications. The approach involves imaging using cross-polarized elastic light scattering and tissue autofluorescence in the Near Infra-Red (NIR) coupled with image processing and inter-image operations to differentiate human tissue components.

Autofluorescence from the outer retina and subretinal space: hypothesis and review.

PubMed

Spaide, Richard

2008-01-01

To review the pathophysiologic principles underlying increased autofluorescence from the outer retina and subretinal space using selected diseases as examples. The ocular imaging information and histopathologic features, when known, were integrated for diseases causing increased autofluorescence from the outer retina and subretinal space. Inferences were taken from this information and used to create a classification scheme. These diseases are principally those that cause separation of the outer retina from the retinal pigment epithelium, thereby preventing proper phagocytosis of photoreceptor outer segments. The separation can arise from increased exudation into the subretinal space or inadequate removal of fluid from the subretinal space. Lack of normal outer segment processing initially leads to increased accumulation of outer segments on the outer retina and subretinal space. Over time, this material is visible as an increasingly thick coating on the outer retina, is yellow, and is autofluorescent. Over time, atrophy develops with thinning of the deposited material and decreasing autofluorescence. The accumulated material is ultimately capable of inducing damage to the retinal pigment epithelium. Diseases causing accumulation of the material include central serous chorioretinopathy, vitelliform macular dystrophy, acute exudative polymorphous vitelliform maculopathy, choroidal tumors, and vitreomacular traction syndrome. The physical separation of the retinal outer segments from the retinal pigment epithelium hinders proper phagocytosis of the outer segments. Accumulation of the shed but not phagocytized outer segments plays a role in disease manifestations for a number of macular diseases.

MULTIMODAL IMAGING OF DISEASE-ASSOCIATED PIGMENTARY CHANGES IN RETINITIS PIGMENTOSA.

PubMed

Schuerch, Kaspar; Marsiglia, Marcela; Lee, Winston; Tsang, Stephen H; Sparrow, Janet R

2016-12-01

Using multiple imaging modalities, we evaluated the changes in photoreceptor cells and retinal pigment epithelium (RPE) that are associated with bone spicule-shaped melanin pigmentation in retinitis pigmentosa. In a cohort of 60 patients with retinitis pigmentosa, short-wavelength autofluorescence, near-infrared autofluorescence (NIR-AF), NIR reflectance, spectral domain optical coherence tomography, and color fundus images were studied. Central AF rings were visible in both short-wavelength autofluorescence and NIR-AF images. Bone spicule pigmentation was nonreflective in NIR reflectance, hypoautofluorescent with short-wavelength autofluorescence and NIR-AF imaging, and presented as intraretinal hyperreflective foci in spectral domain optical coherence tomography images. In areas beyond the AF ring outer border, the photoreceptor ellipsoid zone band was absent in spectral domain optical coherence tomography and the visibility of choroidal vessels in short-wavelength autofluorescence, NIR-AF, and NIR reflectance images was indicative of reduced RPE pigmentation. Choroidal visibility was most pronounced in the zone approaching peripheral areas of bone spicule pigmentation; here RPE/Bruch membrane thinning became apparent in spectral domain optical coherence tomography. These findings are consistent with a process by which RPE cells vacate their monolayer and migrate into inner retina in response to photoreceptor cell degeneration. The remaining RPE spread undergo thinning and consequently become less pigmented. An explanation for the absence of NIR-AF melanin signal in relation to bone spicule pigmentation is not forthcoming.

A Dynamic Graph Cuts Method with Integrated Multiple Feature Maps for Segmenting Kidneys in 2D Ultrasound Images.

PubMed

Zheng, Qiang; Warner, Steven; Tasian, Gregory; Fan, Yong

2018-02-12

Automatic segmentation of kidneys in ultrasound (US) images remains a challenging task because of high speckle noise, low contrast, and large appearance variations of kidneys in US images. Because texture features may improve the US image segmentation performance, we propose a novel graph cuts method to segment kidney in US images by integrating image intensity information and texture feature maps. We develop a new graph cuts-based method to segment kidney US images by integrating original image intensity information and texture feature maps extracted using Gabor filters. To handle large appearance variation within kidney images and improve computational efficiency, we build a graph of image pixels close to kidney boundary instead of building a graph of the whole image. To make the kidney segmentation robust to weak boundaries, we adopt localized regional information to measure similarity between image pixels for computing edge weights to build the graph of image pixels. The localized graph is dynamically updated and the graph cuts-based segmentation iteratively progresses until convergence. Our method has been evaluated based on kidney US images of 85 subjects. The imaging data of 20 randomly selected subjects were used as training data to tune parameters of the image segmentation method, and the remaining data were used as testing data for validation. Experiment results demonstrated that the proposed method obtained promising segmentation results for bilateral kidneys (average Dice index = 0.9446, average mean distance = 2.2551, average specificity = 0.9971, average accuracy = 0.9919), better than other methods under comparison (P < .05, paired Wilcoxon rank sum tests). The proposed method achieved promising performance for segmenting kidneys in two-dimensional US images, better than segmentation methods built on any single channel of image information. This method will facilitate extraction of kidney characteristics that may predict important clinical outcomes such as progression of chronic kidney disease. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Optical metabolic imaging of live tissue cultures

NASA Astrophysics Data System (ADS)

Walsh, Alex J.; Cook, Rebecca S.; Arteaga, Carlos L.; Skala, Melissa C.

2013-02-01

The fluorescence properties, both intensity and fluorescence lifetime, of NADH and FAD, two coenzymes of metabolism, are sensitive, high resolution measures of cellular metabolism. However, often in vivo measurements of tissue are not feasible. In this study, we investigate the stability over time of two-photon auto-fluorescence imaging of NADH and FAD in live-cultured tissues. Our results demonstrate that cultured tissues remain viable for at least several days post excision. Furthermore, the optical redox ratio, NADH fluorescence lifetime, and FAD fluorescence lifetime do not significantly change in the cultured tissues over time. With these findings, we demonstrate the potential of sustained tissue culture techniques for optical metabolic imaging.

Study of experimental endometriosis using fluorescence of eosin-tamoxifen association

NASA Astrophysics Data System (ADS)

Brogniez, A.; Mordon, Serge R.; Devoisselle, Jean-Marie; Querleu, Denis; Brunetaud, Jean Marc

1993-08-01

The main problem of endometriosis is the detection of microscopic and atypical lesions. The successful destruction of these endometriotic sites depends on their detection. This study aimed to develop a spectrofluorometric method to increase the sensitivity of detection of endometriosis. A surgical-induced endometriosis was performed in ten rabbits. Five weeks later, the fluorescence of these endometriotic lesions was studied after injection of tamoxifen and local application of eosin. This fluorescence was compared with that of healthy broad ligament and that obtained without tamoxifen and without eosin. A spectral analysis showed a specific fluorescence of eosin-tamoxifen association, more intense than autofluorescence and selectively observed within endometriosis.

Intensity of continuous renal-replacement therapy in critically ill patients.

PubMed

Bellomo, Rinaldo; Cass, Alan; Cole, Louise; Finfer, Simon; Gallagher, Martin; Lo, Serigne; McArthur, Colin; McGuinness, Shay; Myburgh, John; Norton, Robyn; Scheinkestel, Carlos; Su, Steve

2009-10-22

The optimal intensity of continuous renal-replacement therapy remains unclear. We conducted a multicenter, randomized trial to compare the effect of this therapy, delivered at two different levels of intensity, on 90-day mortality among critically ill patients with acute kidney injury. We randomly assigned critically ill adults with acute kidney injury to continuous renal-replacement therapy in the form of postdilution continuous venovenous hemodiafiltration with an effluent flow of either 40 ml per kilogram of body weight per hour (higher intensity) or 25 ml per kilogram per hour (lower intensity). The primary outcome measure was death within 90 days after randomization. Of the 1508 enrolled patients, 747 were randomly assigned to higher-intensity therapy, and 761 to lower-intensity therapy with continuous venovenous hemodiafiltration. Data on primary outcomes were available for 1464 patients (97.1%): 721 in the higher-intensity group and 743 in the lower-intensity group. The two study groups had similar baseline characteristics and received the study treatment for an average of 6.3 and 5.9 days, respectively (P=0.35). At 90 days after randomization, 322 deaths had occurred in the higher-intensity group and 332 deaths in the lower-intensity group, for a mortality of 44.7% in each group (odds ratio, 1.00; 95% confidence interval [CI], 0.81 to 1.23; P=0.99). At 90 days, 6.8% of survivors in the higher-intensity group (27 of 399), as compared with 4.4% of survivors in the lower-intensity group (18 of 411), were still receiving renal-replacement therapy (odds ratio, 1.59; 95% CI, 0.86 to 2.92; P=0.14). Hypophosphatemia was more common in the higher-intensity group than in the lower-intensity group (65% vs. 54%, P<0.001). In critically ill patients with acute kidney injury, treatment with higher-intensity continuous renal-replacement therapy did not reduce mortality at 90 days. (ClinicalTrials.gov number, NCT00221013.) 2009 Massachusetts Medical Society

Mutant p53 expression in kidney tubules adjacent to renal cell carcinoma: evidence of a precursor lesion.

PubMed

Lai, R; el Dabbagh, L; Mourad, W A

1996-06-01

Neoplastic transformation can be associated with mutations of the p53 gene. This leads to stabilization of its protein product and to its accumulation, which allows immunohistochemical detection. Mutant p53 expression has been seen in many neoplasms, including renal cell carcinoma (RCC). We recently described putative precursor lesions of RCC. The lesions were defined as intratubular epithelial dysplasia (IED) of kidney tubules adjacent to RCC. They were seen in one-third of the cases studied. The findings were based only on light microscopic analysis. We hypothesized that neoplastic transformation would be manifested by mutant p53 expression in the kidney tubules adjacent to RCC and not in nonneoplastic kidneys. Immunohistochemical staining for p53 in 24 cases of RCC with adjacent kidneys was performed. We used the DO-7 monoclonal antibody reactive for the N-terminal of the p53 protein on formalin-fixed paraffin-embedded tissue. Sections from 14 kidneys resected for nonneoplastic conditions were used as controls. Twenty-one (87%) of the 24 cases of RCC had nuclear p53 expression in the tumor cells. This included 14 cases (58%) with intense reactivity and 7 cases (29%) with weaker p53 immunoreactivity. Of the 24 cases of RCC, IED was identified in 13 cases (54%). Immunoreactivity for p53 was focally seen in tubules of all the lesions, as well as in the nonlesional areas. Six of the lesions exhibited intense nuclear staining. The kidneys adjacent to the RCC, with no evidence of IED, showed focally intense positive p53 nuclear staining in four cases. None of the control specimens showed p53 expression. Our findings provide supportive evidence that previously described IED in kidneys adjacent to RCC are most likely precursor lesions of the neoplasm. Aberrant expression of p53 in areas without evidence of IED may suggest that neoplastic transformation manifested by p53 mutation in kidney tubules may be seen before the development of the morphologic features of dysplasia and malignancy.

Multimodal, multiphoton microscopy and image correlation analysis for characterizing corneal thermal damage

NASA Astrophysics Data System (ADS)

Lo, Wen; Chang, Yu-Lin; Liu, Jia-Shiu; Hseuh, Chiu-Mei; Hovhannisyan, Vladimir; Chen, Shean-Jen; Tan, Hsin-Yuan; Dong, Chen-Yuan

2009-09-01

We used the combination of multiphoton autofluorescence (MAF), forward second-harmonic generation (FWSHG), and backward second-harmonic generation (BWSHG) imaging for the qualitative and quantitative characterization of thermal damage of ex vivo bovine cornea. We attempt to characterize the structural alterations by qualitative MAF, FWSHG, and BWSHG imaging in the temperature range of 37 to 90°C. In addition to measuring the absolute changes in the three types of signals at the stromal surface, we also performed image correlation analysis between FWSHG and BWSHG and demonstrate that with increasing thermal damage, image correlation between FWSHG and BWSHG significantly increases. Our results show that while MAF and BWSHG intensities may be used as preliminary indicators of the extent of corneal thermal damage, the most sensitive measures are provided by the decay in FWSHG intensity and the convergence of FWSHG and BWSHG images.

Analysis of albumin Raman scattering in visible and near-infrared ranges

NASA Astrophysics Data System (ADS)

Lykina, Anastasia A.; Artemyev, Dmitry N.

2018-04-01

In this work the analysis of the shape and intensity of albumin Raman signals in visible and near-IR ranges was carried out. The experimental setup using lasers from the visible region first of all excites the fluorescence of the albumin solution, the main contribution to which is produced by sodium chloride, which is a component of the tested sample. At the same time, lasers from the near-infrared range excited the Raman signal of albumin most effectively. It was found that the highest ratio of Raman scattering to autofluorescence intensities in the detected signal was obtained using a laser with a wavelength of 1064 nm. To determine the albumin solution concentration by type of spectrum, a regression approach with the projection to latent structures method was applied. The lowest predicted error of albumin concentration of 2-3 g/l was obtained by using the near-infrared range lasers.

Association between physical activity and kidney function: National Health and Nutrition Examination Survey.

PubMed

Hawkins, Marquis S; Sevick, Mary Ann; Richardson, Caroline R; Fried, Linda F; Arena, Vincent C; Kriska, Andrea M

2011-08-01

Chronic kidney disease is a condition characterized by the deterioration of the kidney's ability to remove waste products from the body. Although treatments to slow the progression of the disease are available, chronic kidney disease may eventually lead to a complete loss of kidney function. Previous studies have shown that physical activities of moderate intensity may have renal benefits. Few studies have examined the effects of total movement on kidney function. The purpose of this study was to determine the association between time spent at all levels of physical activity intensity and sedentary behavior and kidney function. Data were obtained from the 2003-2004 and 2005-2006 National Health and Nutrition Examination Survey, a cross-sectional study of a complex, multistage probability sample of the US population. Physical activity was assessed using an accelerometer and questionnaire. Glomerular filtration rate (eGFR) was estimated using the Modification of Diet in Renal Disease study formula. To assess linear associations between levels of physical activity and sedentary behavior with log-transformed estimated GFR (eGFR), linear regression was used. In general, physical activity (light and total) was related to log eGFR in females and males. For females, the association between light and total physical activity with log eGFR was consistent regardless of diabetes status. For males, the association between light and total physical activity and log eGFR was only significant in males without diabetes. When examining the association between physical activity, measured objectively with an accelerometer, and kidney function, total and light physical activities were found to be positively associated with kidney function.

Mechanism of low-intensity laser therapy as a different etiology for kidney lesion

NASA Astrophysics Data System (ADS)

Koultchavenia, Ekaterina V.

2001-05-01

Urological diseases are widespread among the population. Both infectious-inflammatory and oncological diseases are often diagnosed. Modern antibiotics permit to eradicate infectious agent, but efficiency of therapy is insufficient because of reduction of organ function. Thus, besides aetiotropic therapy pathogenetic effect is necessary. Low- intensity laser therapy (LT) is best pathogenetic treatment, so far as it has a few contraindications, low cost and good tolerance. Our goal was to investigate the influence of LT on different aetiology kidney lesion.

Pancreas Islet Transplantation for Patients With Type 1 Diabetes Mellitus: A Clinical Evidence Review.

PubMed

2015-01-01

Type 1 diabetes mellitus is caused by the autoimmune destruction of pancreatic beta (β) cells, resulting in severe insulin deficiency. Islet transplantation is a β-cell replacement therapeutic option that aims to restore glycemic control in patients with type 1 diabetes. The objective of this study was to determine the clinical effectiveness of islet transplantation in patients with type 1 diabetes, with or without kidney disease. We conducted a systematic review of the literature on islet transplantation for type 1 diabetes, including relevant health technology assessments, systematic reviews, meta-analyses, and observational studies. We used a two-step process: first, we searched for systematic reviews and health technology assessments; second, we searched primary studies to update the chosen health technology assessment. The Assessment of Multiple Systematic Reviews measurement tool was used to examine the methodological quality of the systematic reviews and health technology assessments. We assessed the quality of the body of evidence and the risk of bias according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. Our searched yielded 1,354 citations. One health technology assessment, 11 additional observational studies to update the health technology assessment, one registry report, and four guidelines were included; the observational studies examined islet transplantation alone, islet-after-kidney transplantation, and simultaneous islet-kidney transplantation. In general, low to very low quality of evidence exists for islet transplantation in patients with type 1 diabetes with difficult-to-control blood glucose levels, with or without kidney disease, for these outcomes: health-related quality of life, secondary complications of diabetes, glycemic control, and adverse events. However, high quality of evidence exists for the specific glycemic control outcome of insulin independence compared with intensive insulin therapy. For patients without kidney disease, islet transplantation improves glycemic control and diabetic complications for patients with type 1 diabetes when compared with intensive insulin therapy. However, results for health-related quality of life outcomes were mixed, and adverse events were increased compared with intensive insulin therapy. For patients with type 1 diabetes with kidney disease, islet-after-kidney transplantation or simultaneous islet-kidney transplantation also improved glycemic control and secondary diabetic complications, although the evidence was more limited for this patient group. Compared with intensive insulin therapy, adverse events for islet-after-kidney transplantation or simultaneous islet-kidney transplantation were increased, but were in general less severe than with whole pancreas transplantation. For patients with type 1 diabetes with difficult-to-control blood glucose levels, islet transplantation may be a beneficial β-cell replacement therapy to improve glycemic control and secondary complications of diabetes. However, there is uncertainty in the estimates of effectiveness because of the generally low to very low quality of evidence for all outcomes of interest.

Expression of bone morphogenetic proteins 4, 6 and 7 is downregulated in kidney allografts with interstitial fibrosis and tubular atrophy.

PubMed

Furic-Cunko, Vesna; Kes, Petar; Coric, Marijana; Hudolin, Tvrtko; Kastelan, Zeljko; Basic-Jukic, Nikolina

2015-07-01

Bone morphogenetic proteins (BMPs) are pleiotropic growth factors. This paper investigates the connection between the expression pattern of BMPs in kidney allograft tissue versus the cause of allograft dysfunction. The expression pattern of BMP2, BMP4, BMP6 and BMP7 in 50 kidney allografts obtained by transplant nephrectomy is investigated. Immunohistochemical staining is semiquantitatively evaluated for intensity to identify the expression pattern of BMPs in normal and allograft kidney tissues. The expression of BMP4 is unique between different tubular cell types in grafts without signs of fibrosis. This effect is not found in specimens with high grades of interstitial fibrosis and tubular atrophy (IFTA). In samples with IFTA grades II and III, the BMP7 expression is reduced in a significant fraction of specimens relative to those without signs of IFTA. The expression pattern of BMP6 indicates that its activation may be triggered by the act of transplantation and subsequent reperfusion injury. The expression of BMP2 is strong in all types of tubular epithelial cells and does not differ between the compared allografts and control kidney specimens. The intensity and expression pattern of BMP4, BMP6 and BMP7 in transplanted kidney tissue are found to be dependent upon the length of the transplanted period, the clinical indication for transplant nephrectomy and signs of IFTA in kidney tissue.

pH imaging of mouse kidneys in vivo using a frequency-dependent paraCEST agent

PubMed Central

Wu, Yunkou; Zhang, Shanrong; Soesbe, Todd C.; Yu, Jing; Vinogradov, Elena; Lenkinski, Robert E.; Sherry, A. Dean

2015-01-01

Purpose This study explored the feasibility of using a pH responsive paraCEST agent to image the pH gradient in kidneys of healthy mice. Methods CEST signals were acquired on an Agilent 9.4 T small animal MRI system using a steady-state gradient echo pulse sequence after a bolus injection of agent. The magnetic field inhomogeneity across each kidney was corrected using the WASSR method and pH maps were calculated by measuring the frequency of water exchange signal arising from the agent. Results Dynamic CEST studies demonstrated that the agent was readily detectable in kidneys only between 4 to 12 min post-injection. The CEST images showed a higher signal intensity in the pelvis and calyx regions and lower signal intensity in the medulla and cortex regions. The pH maps reflected tissue pH values spanning from 6.0 to 7.5 in kidneys of healthy mice. Conclusion This study demonstrated that pH maps of the kidney can be imaged in vivo by measuring the pH-dependent chemical shift of a single water exchange CEST peak without prior knowledge of the agent concentration in vivo. The results demonstrate the potential of using a simple frequency-dependent paraCEST agent for mapping tissue pH in vivo. PMID:26173637

Effects of long-term pre- and post-natal exposure to 2.45 GHz wireless devices on developing male rat kidney.

PubMed

Kuybulu, Ayça Esra; Öktem, Faruk; Çiriş, İbrahim Metin; Sutcu, Recep; Örmeci, Ahmet Rıfat; Çömlekçi, Selçuk; Uz, Efkan

2016-01-01

The aim of the present study was to investigate oxidative stress and apoptosis in kidney tissues of male Wistar rats that pre- and postnatally exposed to wireless electromagnetic field (EMF) with an internet frequency of 2.45 GHz for a long time. The study was conducted in three groups of rats which were pre-natal, post-natal. and sham exposed groups. Oxidative stress markers and histological evaluation of kidney tissues were studied. Renal tissue malondialdehyde (MDA) and total oxidant (TOS) levels of pre-natal group were high and total antioxidant (TAS) and superoxide dismutase (SOD) levels were low. Spot urine NAG/creatinine ratio was significantly higher in pre- and post-natal groups (p < 0.001). Tubular injury was detected in most of the specimens in post-natal groups. Immunohistochemical analysis showed low-intensity staining with Bax in cortex, high-intensity staining with Bcl-2 in cortical and medullar areas of pre-natal group (p values, 0.000, 0.002, 0.000, respectively) when compared with sham group. Bcl2/Bax staining intensity ratios of medullar and cortical area was higher in pre-natal group than sham group (p = 0.018, p = 0.011). Based on this study, it is thought that chronic pre- and post-natal period exposure to wireless internet frequency of EMF may cause chronic kidney damages; staying away from EMF source in especially pregnancy and early childhood period may reduce negative effects of exposure on kidney.

Advanced glycation end products are associated with arterial stiffness in type 1 diabetes.

PubMed

Llauradó, Gemma; Ceperuelo-Mallafré, Victòria; Vilardell, Carme; Simó, Rafael; Gil, Pilar; Cano, Albert; Vendrell, Joan; González-Clemente, José-Miguel

2014-06-01

The aim of this study was to investigate the relationship between advanced glycation end products (AGEs) and arterial stiffness (AS) in subjects with type 1 diabetes without clinical cardiovascular events. A set of 68 patients with type 1 diabetes and 68 age- and sex-matched healthy subjects were evaluated. AGEs were assessed using serum concentrations of N-carboxy-methyl-lysine (CML) and using skin autofluorescence. AS was assessed by aortic pulse wave velocity (aPWV), using applanation tonometry. Patients with type 1 diabetes had higher serum concentrations of CML (1.18 vs 0.96 μg/ml; P=0.008) and higher levels of skin autofluorescence (2.10 vs 1.70; P<0.001) compared with controls. These differences remained significant after adjustment for classical cardiovascular risk factors. Skin autofluorescence was positively associated with aPWV in type 1 diabetes (r=0.370; P=0.003). No association was found between CML and aPWV. Skin autofluorescence was independently and significantly associated with aPWV in subjects with type 1 diabetes (β=0.380; P<0.001) after adjustment for classical cardiovascular risk factors. Additional adjustments for HbA1c, disease duration, and low-grade inflammation did not change these results. In conclusion, skin accumulation of autofluorescent AGEs is associated with AS in subjects with type 1 diabetes and no previous cardiovascular events. These findings indicate that determination of tissue AGE accumulation may be a useful marker for AS in type 1 diabetes. © 2014 Society for Endocrinology.

Functional assessment of the fundus autofluorescence pattern in Best vitelliform macular dystrophy.

PubMed

Parodi, Maurizio Battaglia; Iacono, Pierluigi; Del Turco, Claudia; Triolo, Giacinto; Bandello, Francesco

2016-07-01

To identify the fundus autofluorescence (FAF) patterns in Best vitelliform macular dystrophy (VMD). Patients affected by VMD in vitelliform, pseudohypopyon, and vitelliruptive stages underwent a complete ophthalmological examination, including best-corrected visual acuity (BCVA), short-wavelength FAF (SW-FAF), near-infrared FAF (NIR-FAF) and microperimetry. the identification of the correlation between SW-FAF and NIR-FAF patterns of the foveal region with BCVA, and central retinal sensitivity in eyes affected by VMD. The secondary outcomes included the definition of the frequency of foveal patterns on SW-FAF and NIR-FAF. Thirty-seven of 64 (58 %), 8 of 64 (12.5 %) and 19 of 64 (29.5 %) eyes showed vitelliform, pseudohypopyon, and vitelliruptive stages respectively. Three main FAF patterns were identified on both techniques: hyper-autofluorescent pattern, hypo-autofluorescent pattern, and patchy pattern. BCVA was significantly different in eyes with hypo-autofluorescent and patchy patterns with respect to eyes showing a hyper-autofluorescent pattern. Similar differences were registered in the FS according to SW-FAF classification. However, the FS differed in each subgroup in the NIR-FAF analysis. Subgroup analyses were performed on the patchy pattern, combining FAF and fundus abnormalities. Considering both FAF techniques, the BCVA differed between the vitelliform and pseudohypopyon stages, and between the vitelliform and vitelliruptive stages. In the NIR-FAF classification, there was a significant statistical difference in the FS between each subgroup; in the SW-FAF, there was a significant difference between the vitelliform and pseudohypopyon stages and the vitelliform and vitelliruptive stages. Three main FAF patterns can be identified in VMD. The patchy pattern is the most frequent, accounting for 70 % of eyes on SW-FAF and 80 % of eyes on NIR-FAF. A tighter correlation links the classification of NIR-FAF patterns and FS. Longitudinal investigations are warranted to evaluate the course of FAF patterns and their role in disease monitoring.

Autofluorescence multiphoton microscopy for visualization of tissue morphology and cellular dynamics in murine and human airways.

PubMed

Kretschmer, Sarah; Pieper, Mario; Hüttmann, Gereon; Bölke, Torsten; Wollenberg, Barbara; Marsh, Leigh M; Garn, Holger; König, Peter

2016-08-01

The basic understanding of inflammatory airway diseases greatly benefits from imaging the cellular dynamics of immune cells. Current imaging approaches focus on labeling specific cells to follow their dynamics but fail to visualize the surrounding tissue. To overcome this problem, we evaluated autofluorescence multiphoton microscopy for following the motion and interaction of cells in the airways in the context of tissue morphology. Freshly isolated murine tracheae from healthy mice and mice with experimental allergic airway inflammation were examined by autofluorescence multiphoton microscopy. In addition, fluorescently labeled ovalbumin and fluorophore-labeled antibodies were applied to visualize antigen uptake and to identify specific cell populations, respectively. The trachea in living mice was imaged to verify that the ex vivo preparation reflects the in vivo situation. Autofluorescence multiphoton microscopy was also tested to examine human tissue from patients in short-term tissue culture. Using autofluorescence, the epithelium, underlying cells, and fibers of the connective tissue, as well as blood vessels, were identified in isolated tracheae. Similar structures were visualized in living mice and in the human airway tissue. In explanted murine airways, mobile cells were localized within the tissue and we could follow their migration, interactions between individual cells, and their phagocytic activity. During allergic airway inflammation, increased number of eosinophil and neutrophil granulocytes were detected that moved within the connective tissue and immediately below the epithelium without damaging the epithelial cells or connective tissues. Contacts between granulocytes were transient lasting 3 min on average. Unexpectedly, prolonged interactions between granulocytes and antigen-uptaking cells were observed lasting for an average of 13 min. Our results indicate that autofluorescence-based imaging can detect previously unknown immune cell interactions in the airways. The method also holds the potential to be used during diagnostic procedures in humans if integrated into a bronchoscope.

Near-infrared fundus autofluorescence in subclinical best vitelliform macular dystrophy.

PubMed

Parodi, Maurizio Battaglia; Iacono, Pierluigi; Del Turco, Claudia; Bandello, Francesco

2014-12-01

To describe fundus autofluorescence (FAF) on short-wavelength FAF and near-infrared FAF in the subclinical form of Best vitelliform macular dystrophy. Cross-sectional prospective study. Patients affected by the subclinical form of Best vitelliform macular dystrophy (positive testing for BEST1 gene mutation, fully preserved best-corrected visual acuity, normal fundus appearance) were recruited. Each patient underwent a complete ophthalmologic examination, including electro-oculogram (EOG), short-wavelength FAF, near-infrared FAF, spectral-domain OCT (SD OCT), and microperimetry. Main outcome measure was the identification of abnormal FAF patterns. Forty-six patients showing mutations in the BEST1 gene were examined. Forty patients presented a bilateral Best vitelliform macular dystrophy, 2 patients showed a unilateral Best vitelliform macular dystrophy, and 4 patients had a bilateral subclinical form. Patients with the unilateral form (2 eyes) and patients with the subclinical form (8 eyes) were analyzed. Three BEST1 sequence variants were identified: c.73C>T (p.Arg25Trp), c.28G>A (p.Ala10Thr), and c.652C>G (p.Arg218Gly). Short-wavelength FAF was normal in all eyes. Near-infrared FAF detected a pattern consisting of a central hypo-autofluorescence surrounded by a round area of hyper-autofluorescence. A bilateral reduced EOG response was detected in 1 patient. SD OCT revealed a thicker, well-defined, and more reflective interdigitation zone in 2 patients (4 eyes, 40%). Microperimetry of the central 10 degrees revealed a slight, diffuse reduction of retinal sensitivity. Mean retinal sensitivity within the central 2 and 4 degrees was lower and matched the hypo-autofluorescent area detected on near-infrared FAF. Additional relative scotomata were detected within the 10-degree area. No change in clinical, functional, or FAF pattern was found over the follow-up. Subclinical Best vitelliform macular dystrophy is characterized by the absence of biomicroscopic fundus abnormality and fully preserved visual acuity, but shows an abnormal near-infrared FAF pattern, with central hypo-autofluorescence. Copyright © 2014 Elsevier Inc. All rights reserved.

Persistence of Only a Minute Viable Population in Chlorotic Microcystis aeruginosa PCC 7806 Cultures Obtained by Nutrient Limitation.

PubMed

Meireles, Diogo de Abreu; Schripsema, Jan; Arnholdt, Andrea Cristina Vetö; Dagnino, Denise

2015-01-01

Cultures from the cyanobacterial strain Microcystis aeruginosa PCC 7806 submitted to nutrient limitation become chlorotic. When returned to nutrient rich conditions these cultures regain their green colour. The aim of this study was to verify whether the cells in these cultures could be considered resting stages allowing the survival of periods of nutrient starvation as has been reported for Synechococcus PCC 7942. The experiments with Microcystis were carried out in parallel with Synechococcus cultures to rule out the possibility that any results obtained with Microcystis were due to our particular experimental conditions. The results of the experiments with Synechococcus PCC 7942 cultures were comparable to the reported in the literature. For Microcystis PCC 7806 a different response was observed. Analysis of chlorotic Microcystis cultures by flow cytometry showed that the phenotype of the cells in the population was not homogenous: the amount of nucleic acids was about the same in all cells but only around one percent of the population emitted red autofluorescence indicating the presence of chlorophyll. Monitoring of the reversion of chlorosis by flow cytometry showed that the re-greening was most likely the result of the division of the small population of red autofluorescent cells originally present in the chlorotic cultures. This assumption was confirmed by analysing the integrity of the DNA and the membrane permeability of the cells of chlorotic cultures. Most of the DNA of these cultures was degraded and only the autofluorescent population of the chlorotic cultures showed membrane integrity. Thus, contrary to what has been reported for other cyanobacterial genera, most of the cells in chlorotic Microcystis cultures are not resting stages but dead. It is interesting to note that the red autofluorescent cells of green and chlorotic cultures obtained in double strength ASM-1 medium differ with respect to metabolism: levels of emission of red autofluorescence are higher in the cells of green cultures and the ability to convert fluorescein diacetate of these cells are heterogeneous when compared to the autofluorescent cells of chlorotic cultures. Thus, the small population of the red autofluorescent cells of chlorotic cultures are in a differentiated metabolic state that allow them to persist in conditions in which most of the population loses viability; persistent cells can be detected in chlorotic cultures maintained for more than a year.

Persistence of Only a Minute Viable Population in Chlorotic Microcystis aeruginosa PCC 7806 Cultures Obtained by Nutrient Limitation

PubMed Central

de Abreu Meireles, Diogo; Schripsema, Jan; Vetö Arnholdt, Andrea Cristina; Dagnino, Denise

2015-01-01

Cultures from the cyanobacterial strain Microcystis aeruginosa PCC 7806 submitted to nutrient limitation become chlorotic. When returned to nutrient rich conditions these cultures regain their green colour. The aim of this study was to verify whether the cells in these cultures could be considered resting stages allowing the survival of periods of nutrient starvation as has been reported for Synechococcus PCC 7942. The experiments with Microcystis were carried out in parallel with Synechococcus cultures to rule out the possibility that any results obtained with Microcystis were due to our particular experimental conditions. The results of the experiments with Synechococcus PCC 7942 cultures were comparable to the reported in the literature. For Microcystis PCC 7806 a different response was observed. Analysis of chlorotic Microcystis cultures by flow cytometry showed that the phenotype of the cells in the population was not homogenous: the amount of nucleic acids was about the same in all cells but only around one percent of the population emitted red autofluorescence indicating the presence of chlorophyll. Monitoring of the reversion of chlorosis by flow cytometry showed that the re-greening was most likely the result of the division of the small population of red autofluorescent cells originally present in the chlorotic cultures. This assumption was confirmed by analysing the integrity of the DNA and the membrane permeability of the cells of chlorotic cultures. Most of the DNA of these cultures was degraded and only the autofluorescent population of the chlorotic cultures showed membrane integrity. Thus, contrary to what has been reported for other cyanobacterial genera, most of the cells in chlorotic Microcystis cultures are not resting stages but dead. It is interesting to note that the red autofluorescent cells of green and chlorotic cultures obtained in double strength ASM-1 medium differ with respect to metabolism: levels of emission of red autofluorescence are higher in the cells of green cultures and the ability to convert fluorescein diacetate of these cells are heterogeneous when compared to the autofluorescent cells of chlorotic cultures. Thus, the small population of the red autofluorescent cells of chlorotic cultures are in a differentiated metabolic state that allow them to persist in conditions in which most of the population loses viability; persistent cells can be detected in chlorotic cultures maintained for more than a year. PMID:26181753

Factors associated with maternal death in an intensive care unit

PubMed Central

Saintrain, Suzanne Vieira; de Oliveira, Juliana Gomes Ramalho; Saintrain, Maria Vieira de Lima; Bruno, Zenilda Vieira; Borges, Juliana Lima Nogueira; Daher, Elizabeth De Francesco; da Silva Jr, Geraldo Bezerra

2016-01-01

Objective To identify factors associated with maternal death in patients admitted to an intensive care unit. Methods A cross-sectional study was conducted in a maternal intensive care unit. All medical records of patients admitted from January 2012 to December 2014 were reviewed. Pregnant and puerperal women were included; those with diagnoses of hydatidiform mole, ectopic pregnancy, or anembryonic pregnancy were excluded, as were patients admitted for non-obstetrical reasons. Death and hospital discharge were the outcomes subjected to comparative analysis. Results A total of 373 patients aged 13 to 45 years were included. The causes for admission to the intensive care unit were hypertensive disorders of pregnancy, followed by heart disease, respiratory failure, and sepsis; complications included acute kidney injury (24.1%), hypotension (15.5%), bleeding (10.2%), and sepsis (6.7%). A total of 28 patients died (7.5%). Causes of death were hemorrhagic shock, multiple organ failure, respiratory failure, and sepsis. The independent risk factors associated with death were acute kidney injury (odds ratio [OR] = 6.77), hypotension (OR = 15.08), and respiratory failure (OR = 3.65). Conclusion The frequency of deaths was low. Acute kidney injury, hypotension, and respiratory insufficiency were independent risk factors for maternal death. PMID:28099637

Glucose-lowering agents for treating pre-existing and new-onset diabetes in kidney transplant recipients.

PubMed

Lo, Clement; Jun, Min; Badve, Sunil V; Pilmore, Helen; White, Sarah L; Hawley, Carmel; Cass, Alan; Perkovic, Vlado; Zoungas, Sophia

2017-02-27

Kidney transplantation is the preferred form of kidney replacement therapy for patients with end-stage kidney disease (ESKD) and is often complicated by worsening or new-onset diabetes. Management of hyperglycaemia is important to reduce post-transplant and diabetes-related complications. The safety and efficacy of glucose-lowering agents after kidney transplantation is largely unknown. To evaluate the efficacy and safety of pharmacological interventions for lowering glucose levels in patients who have undergone kidney transplantation and have diabetes. We searched the Cochrane Kidney and Transplant Specialised Register to 15 April 2016 through contact with the Information Specialist using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE, and EMBASE; handsearching conference proceedings; and searching the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. All randomised controlled trials (RCTs), quasi-RCTs and cross-over studies examining head-to-head comparisons of active regimens of glucose-lowering therapy or active regimen compared with placebo/standard care in patients who have received a kidney transplant and have diabetes were eligible for inclusion. Two authors independently assessed study eligibility and quality and performed data extraction. Continuous outcomes were expressed as post-treatment mean differences (MD) or standardised mean difference (SMD). Adverse events were expressed as post-treatment absolute risk differences (RD). Dichotomous clinical outcomes were presented as risk ratios (RR) with 95% confidence intervals (CI). We included seven studies that involved a total of 399 kidney transplant recipients. All included studies had observed heterogeneity in the patient population, interventions and measured outcomes or missing data (which was unavailable despite correspondence with authors). Many studies had incompletely reported methodology preventing meta-analysis and leading to low confidence in treatment estimates.Three studies with 241 kidney transplant recipients examined the use of more intensive compared to less intensive insulin therapy in kidney transplant recipients with pre-existing type 1 or 2 diabetes. Evidence for the effects of more intensive compared to less intensive insulin therapy on transplant graft survival, HbA1c, fasting blood glucose, all cause mortality and adverse effects including hypoglycaemia was of very low quality. More intensive versus less intensive insulin therapy resulted in no difference in transplant or graft survival over three to five years in one study while another study showed that more intensive versus less intensive insulin therapy resulted in more rejection events over the three year follow-up (11 events in total; 9 in the more intensive group, P = 0.01). One study showed that more intensive insulin therapy resulted in a lower mean HbA1c (10 ± 0.8% versus 13 ± 0.9%) and lower fasting blood glucose (7.22 ± 0.5 mmol/L versus 13.44 ± 1.22 mmol/L) at 13 months compared with standard insulin therapy. Another study showed no difference between more intensive compared to less intensive insulin therapy on all-cause mortality over a five year follow-up period. All studies showed either an increased frequency of hypoglycaemia or severe hypoglycaemia episodes.Three studies with a total of 115 transplant recipients examined the use of DPP4 inhibitors for new-onset diabetes after transplantation. Evidence for the treatment effect of DPP4 inhibitors on transplant or graft survival, HbA1c and fasting blood glucose levels, all cause mortality, and adverse events including hypoglycaemia was of low quality. One study comparing vildagliptin to placebo and another comparing sitagliptin to placebo showed no difference in transplant or graft survival over two to four months of follow-up. One study comparing vildagliptin to placebo showed no significant change in estimated glomerular filtration rate from baseline (1.9 ± 10.3 mL/min/1.73 m 2 , P = 0.48 and 2.1 ± 6.1 mL/min/1.73 m 2 , P = 0.22) and no deaths, in either treatment group over three months of follow-up. One study comparing vildagliptin to placebo showed a lower HbA1c level (mean ± SD) (6.3 ± 0.5% versus versus 6.7 ± 0.6%, P = 0.03) and trend towards a greater lowering of fasting blood glucose (-0.91 ± -0.92 mmol/L versus vs -0.19 ± 1.16 mmol/L, P = 0.08) with vildagliptin. One study comparing sitagliptin to insulin glargine showed an equivalent lowering of HbA1c (-0.6 ± 0.5% versus -0.6 ± 0.6%, P = NS) and fasting blood glucose (4.92 ± 1.42 versus 4.76 ± 1.09 mmol/L, P = NS) with sitagliptin. For the outcome of hypoglycaemia, one study comparing vildagliptin to placebo reported no episodes of hypoglycaemia, one study comparing sitagliptin to insulin glargine reported fewer episodes of hypoglycaemia with sitagliptin (3/28 patients; 10.7% versus 5/28; 17.9%) and one cross-over study of sitagliptin and placebo reported two episodes of asymptomatic moderate hypoglycaemia (2 to 3.9 mmol/L) when sitagliptin was administered with glipizide. All three studies reported no drug interactions between DPP4 inhibitors and the immunosuppressive agents taken.Evidence for the treatment effect of pioglitazone for treating pre-existing diabetes was of low quality. One study with 62 transplant recipients compared the use of pioglitazone with insulin to insulin alone for treating pre-existing diabetes. Pioglitazone resulted in a lower HbA1c level (mean ± SD) (-1.21 ± 1.2 versus 0.39 ± 1%, P < 0.001) but had no effects on fasting blood glucose (6.58 ± 2.71 versus 7.28 ± 2.78 mmol/L, P = 0.14 ), and change in creatinine (3.54 ± 15.03 versus 10.61 ± 18.56 mmol/L, P = 0.53) and minimal adverse effects (no episodes of hypoglycaemia, three dropped out due to mild to moderate lower extremity oedema, cyclosporin levels were not affected). Evidence concerning the efficacy and safety of glucose-lowering agents for treating pre-existing and new-onset diabetes in kidney transplant recipients is limited. Existing studies examine more intensive versus less intensive insulin therapy, and the use of DPP4 inhibitors and pioglitazone. The safety and efficacy of more intensive compared to less intensive insulin therapy is very uncertain and the safety and efficacy of DPP4 inhibitors and pioglitazone is uncertain, due to data being limited and of poor quality. Additional RCTs are required to clarify the safety and efficacy of current glucose-lowering agents for kidney transplant recipients with diabetes.

Texture Feature Analysis for Different Resolution Level of Kidney Ultrasound Images

NASA Astrophysics Data System (ADS)

Kairuddin, Wan Nur Hafsha Wan; Mahmud, Wan Mahani Hafizah Wan

2017-08-01

Image feature extraction is a technique to identify the characteristic of the image. The objective of this work is to discover the texture features that best describe a tissue characteristic of a healthy kidney from ultrasound (US) image. Three ultrasound machines that have different specifications are used in order to get a different quality (different resolution) of the image. Initially, the acquired images are pre-processed to de-noise the speckle to ensure the image preserve the pixels in a region of interest (ROI) for further extraction. Gaussian Low- pass Filter is chosen as the filtering method in this work. 150 of enhanced images then are segmented by creating a foreground and background of image where the mask is created to eliminate some unwanted intensity values. Statistical based texture features method is used namely Intensity Histogram (IH), Gray-Level Co-Occurance Matrix (GLCM) and Gray-level run-length matrix (GLRLM).This method is depends on the spatial distribution of intensity values or gray levels in the kidney region. By using One-Way ANOVA in SPSS, the result indicated that three features (Contrast, Difference Variance and Inverse Difference Moment Normalized) from GLCM are not statistically significant; this concludes that these three features describe a healthy kidney characteristics regardless of the ultrasound image quality.

Novel biomarkers of acute kidney injury and failure: clinical applicability.

PubMed

Mårtensson, J; Martling, C-R; Bell, M

2012-12-01

Acute kidney injury (AKI) has a number of triggers, including ischaemia, nephrotoxins, radiocontrast, and bacterial endotoxins. It occurs in around one-third of patients treated in intensive care unit (ICU) and is even more prevalent in cardiac surgery patients. There is a higher mortality in patients with AKI compared with non-AKI counterparts, and in severe AKI requiring renal support, the 6 month mortality is >50%. Unlike the progressive development of biomarkers in cardiology, there have been few changes in kidney diagnostic markers. Creatinine is still used as an indicator of kidney function but not of the parenchymal kidney injury. Serum creatinine (sCr) concentration does not change until around 50% of kidney function is lost, and varies with muscle mass, age, sex, medications, and hydration status. The lag time between injury and loss of function, risks missing a therapeutic opportunity, and may explain the high associated mortality. Novel biomarkers of AKI- and failure include neutrophil gelatinase-associated lipocalin, N-acetyl-β-d-glucosaminidase, kidney injury molecule-1, interleukin-18, and cystatin C. The pathophysiology associated with accumulation of these markers in plasma and urine is not clear, but a common denominator is inflammation. Some of these new AKI biomarkers may have clinical applicability in anaesthesia and intensive care in the future. It is possible that a 'kidney biomarker panel' will become standard before and after major surgery. If elevated or positive, the anaesthetist must take special care to optimize the patients after operation on the surgical wards or ICU to avoid further nephrotoxic insults and initiate supplementary care.

Fundus autofluorescence applications in retinal imaging

PubMed Central

Gabai, Andrea; Veritti, Daniele; Lanzetta, Paolo

2015-01-01

Fundus autofluorescence (FAF) is a relatively new imaging technique that can be used to study retinal diseases. It provides information on retinal metabolism and health. Several different pathologies can be detected. Peculiar AF alterations can help the clinician to monitor disease progression and to better understand its pathogenesis. In the present article, we review FAF principles and clinical applications. PMID:26139802

Modeling of the Autofluorescence Spectra of the Crystalline Lens with Cataract Taking into Account Light Scattering

NASA Astrophysics Data System (ADS)

Shapovalov, K. A.; Salmin, V. V.; Lazarenko, V. I.; Gar‧kavenko, V. V.

2017-05-01

The model of the autofluorescence spectrum formation of a crystalline lens taking into account light scattering was presented. Cross sections of extinction, scattering and absorption were obtained numerically for models of normal crystalline lens and cataract according to the Mie theory for polydisperse systems. To validate the model, data on the autofluorescence spectra of the normal lens and cataracts were obtained using an experimental ophthalmologic spectrofluorometer with excitation by UV light emitting diodes. In the framework of the model, the influence of the lens light scattering on the shape of the luminescence spectrum was estimated. It was found that the changes in the fluorescence spectrum of lenses with cataracts can be completely interpreted by the light scattering.

Laser-induced fluorescence imaging of bacteria

NASA Astrophysics Data System (ADS)

Hilton, Peter J.

1998-12-01

This paper outlines a method for optically detecting bacteria on various backgrounds, such as meat, by imaging their laser induced auto-fluorescence response. This method can potentially operate in real-time, which is many times faster than current bacterial detection methods, which require culturing of bacterial samples. This paper describes the imaging technique employed whereby a laser spot is scanned across an object while capturing, filtering, and digitizing the returned light. Preliminary results of the bacterial auto-fluorescence are reported and plans for future research are discussed. The results to date are encouraging with six of the eight bacterial strains investigated exhibiting auto-fluorescence when excited at 488 nm. Discrimination of these bacterial strains against red meat is shown and techniques for reducing background fluorescence discussed.

Combining casein phosphopeptide-amorphous calcium phosphate with fluoride: synergistic remineralization potential of artificially demineralized enamel or not?

NASA Astrophysics Data System (ADS)

Elsayad, Iman; Sakr, Amal; Badr, Yahia

2009-07-01

Recaldent is a product of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). The remineralizing potential of CPP-ACP per se, or when combined with 0.22% Fl gel on artificially demineralized enamel using laser florescence, is investigated. Mesial surfaces of 15 sound human molars are tested using a He-Cd laser beam at 441.5 nm with 18-mW power as an excitation source on a suitable setup based on a Spex 750-M monochromator provided with a photomultiplier tube (PMT) for detection of collected autofluorescence from sound enamel. Mesial surfaces are subjected to demineralization for ten days. The spectra from demineralized enamel are measured. Teeth are divided into three groups according to the remineralizing regimen: group 1 Recaldent per se, group 2 Recaldent combined with fluoride gel and ACP, and group 3 artificial saliva as a positive control. After following these protocols for three weeks, the spectra from the remineralized enamel are measured. The spectra of enamel autofluorescence are recorded and normalized to peak intensity at about 540 nm to compare spectra from sound, demineralized, and remineralized enamel surfaces. A slight red shift occurred in spectra from demineralized enamel, while a blue shift may occur in remineralized enamel. Group 2 shows the highest remineralizing potential. Combining fluoride and ACP with CPP-ACP can give a synergistic effect on enamel remineralization.

Multispectral detection of cutaneous lesions using spectroscopy and microscopy approaches

NASA Astrophysics Data System (ADS)

Borisova, E.; Genova-Hristova, Ts.; Troyanova, P.; Pavlova, E.; Terziev, I.; Semyachkina-Glushkovskaya, O.; Lomova, M.; Genina, E.; Stanciu, G.; Tranca, D.; Avramov, L.

2018-02-01

Autofluorescence, diffuse-reflectance and transmission spectral, and microscopic measurements were made on different cutaneous neoplastic lesions, namely basal cell carcinoma, squamous cell carcinoma, malignant melanoma, and dysplastic and benign lesions related. Spectroscopic measurements were made on ex vivo tissue samples, and confocal microscopy investigations were made on thin tissue slices. Fluorescence spectra obtained reveal statistically significant differences between the different benign, dysplastic and malignant lesions by the level of emission intensity, as well by spectral shape, which are fingerprints applicable for differentiation algorithms. In reflectance mode the most significant differences are related to the influence of skin pigments - melanin and hemoglobin. Transmission spectroscopy mode gave complementary optical properties information about the tissue samples investigated to that one of reflectance and absorption spectroscopy. Using autofluorescence detection of skin lesions we obtain very good diagnostic performance for distinguishing of nonmelanoma lesions. Using diffuse reflectance and transmission spectroscopy we obtain significant tool for pigmented pathologies differentiation, but it is a tool with moderate sensitivity for non-melanoma lesions detection. One could rapidly increase the diagnostic accuracy of the received combined "optical biopsy" method when several spectral detection techniques are applied in common algorithm for lesions' differentiation. Specific spectral features observed in each type of lesion investigated on micro and macro level would be presented and discussed. Correlation between the spectral data received and the microscopic features observed would be discussed in the report.

Spectral characteristics of caries-related autofluorescence spectra and their use for diagnosis of caries stage

NASA Astrophysics Data System (ADS)

Son, Sung-Ae; Jung, Kyeong-Hoon; Ko, Ching-Chang; Kwon, Yong Hoon

2016-01-01

The purpose of the present study was to identify factors useful for diagnosis of the caries stage from laser-induced autofluorescence (AF) spectra. Affected teeth were accurately staged and allocated to four groups: sound, stage II, stage III, or stage IV. A 405-nm laser was used to produce AF spectra. The spectrum factors analyzed were spectrum slope at 550 to 600 nm, spectral area from 500 and 590 nm, and intensity ratio of peaks 625 and 667 nm (625/667 nm). DIAGNOdent was used as control measurement. AF spectra of sound teeth had a peak near 500 nm followed by a smooth decline to 800 nm. As caries progressed, some specimens in stages II to IV showed one or two peak(s) near 625 and 667 nm. Slopes at 550 to 600 nm and areas under the curve at 500 to 590 nm were significantly different (p<0.001) for each stage. Two-peak ratios were also significantly different (p<0.001) except for stage III and stage IV. DIAGNOdent readings for sound and stage II and stage III and IV were not significantly different. Among the studied factors, the spectrum slope at 550 to 600 nm and area under curve at 500 to 590 nm could be useful treatment decision-making tools for carious lesions.

Fluctuation localization imaging-based fluorescence in situ hybridization (fliFISH) for accurate detection and counting of RNA copies in single cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, Yi; Hu, Dehong; Markillie, Lye Meng

Quantitative gene expression analysis in intact single cells can be achieved using single molecule- based fluorescence in situ hybridization (smFISH). This approach relies on fluorescence intensity to distinguish between true signals, emitted from an RNA copy hybridized with multiple FISH sub-probes, and background noise. Thus, the precision in smFISH is often compromised by partial or nonspecific binding of sub-probes and tissue autofluorescence, limiting its accuracy. Here we provide an accurate approach for setting quantitative thresholds between true and false signals, which relies on blinking frequencies of photoswitchable dyes. This fluctuation localization imaging-based FISH (fliFISH) uses blinking frequency patterns, emitted frommore » a transcript bound to multiple sub-probes, which are distinct from blinking patterns emitted from partial or nonspecifically bound sub-probes and autofluorescence. Using multicolor fliFISH, we identified radial gene expression patterns in mouse pancreatic islets for insulin, the transcription factor, NKX2-2, and their ratio (Nkx2-2/Ins2). These radial patterns, showing higher values in β cells at the islet core and lower values in peripheral cells, were lost in diabetic mouse islets. In summary, fliFISH provides an accurate, quantitative approach for detecting and counting true RNA copies and rejecting false signals by their distinct blinking frequency patterns, laying the foundation for reliable single-cell transcriptomics.« less

Kidney-Heart Interactions in Acute Kidney Injury.

PubMed

Doi, Kent

2016-01-01

Acute kidney injury (AKI) is a common complication in critically ill patients treated in intensive care units. Renal replacement therapy (RRT)-requiring AKI occurs in approximately 5-10% patients in intensive care unit and their mortality rate is unacceptably high (50-60%), despite sufficient control of uremia using remarkably advanced modern RRT techniques. This suggests that there are unrecognized organ interactions following AKI that could worsen the outcomes. Cardiorenal syndrome has been defined based on clinical observations that acute and chronic heart failure causes kidney injury and AKI and that chronic kidney disease worsens heart diseases. Possible pathways that connect these 2 organs have been suggested; however, the precise mechanisms are yet to be clarified, particularly in AKI-induced cardiac dysfunction. This review focuses on acute cardiac dysfunction in the setting of AKI. A recent animal study demonstrated the dysregulation of mitochondrial dynamics caused by an increased dynamin-related protein 1 expression and cellular apoptosis of the heart in a renal ischemia reperfusion model. Although the precise mechanisms that induce cardiac mitochondrial injury in AKI remain unclear, cardiac mitochondria injury could be a novel candidate of drug targets against high mortality in severe AKI. © 2016 S. Karger AG, Basel.

Simultaneous evaluation of renal morphology and function in live kidney donors using dynamic magnetic resonance imaging.

PubMed

Artunc, F; Yildiz, S; Rossi, C; Boss, A; Dittmann, H; Schlemmer, H P; Risler, T; Heyne, N

2010-06-01

Evaluation of potential kidney donors requires the assessment of both kidney anatomy and function. In this prospective study, we sought to expand the diagnostic yield of magnetic resonance (MR) by adding functional measurements of glomerular filtration rate (GFR) and split renal function. Between 2007 and 2009, all potential kidney donors presenting to our facility underwent a comprehensive single-stop MR study that included an assessment of anatomy, angiography and functional measurements. GFR was measured after a bolus injection of gadobutrol (4 ml, approximately 0.05 mmol/kg) and calculated from the washout of the signal intensity obtained over the liver. Split renal function was calculated from the increase of signal intensity over the renal cortex. Values were compared to renal scintigraphy with (99m)Tc-DTPA from the same day. The MR investigation was successfully performed in 21 participants. The GFR derived from MR (MR-GFR) correlated well (r = 0.84) with the GFR derived from scintigraphy (DTPA-GFR). The mean value of the paired differences was 4 +/- 13 [SD] ml/min/1.73 m(2) and was not significantly different from zero. The ratio between right and left kidney function was similar with both techniques (1.01 +/- 0.17 with MR and 1.06 +/- 0.12 with scintigraphy, P = 0.20). We demonstrate an MR-based approach to comprehensively evaluate both kidney anatomy and function in a single investigation, thereby facilitating the evaluation of potential kidney donors.

Fluorescence detection and photodynamic activity of endogenous protoporphyrin in human skin

NASA Astrophysics Data System (ADS)

Koenig, Karsten; Rueck, Angelika C.; Schneckenburger, Herbert

1992-07-01

Human skin shows a strong autofluorescence in the red spectral region with main peaks around 600, 620, and 640 nm caused by the porphyrin production of the gram positive lipophile skin bacterium Propionibacterium acnes. Irradiation of these bacteria reduces the integral fluorescence intensity and induces the formation of photoproducts with fluorescence bands around 670 nm and decay times of about 1 and 5 ns. The photoproduct formation is connected with an increased absorption in the red spectral region. The endogenous fluorescent porphyrins act as photosensitizers. Photodestruction of Propionibacteria acnes by visible light appears therefore to be a promising therapy. The photodynamic activity of the photoproducts was lower than that of protoporphyrin IX.

Pancreas Islet Transplantation for Patients With Type 1 Diabetes Mellitus: A Clinical Evidence Review

PubMed Central

2015-01-01

Background Type 1 diabetes mellitus is caused by the autoimmune destruction of pancreatic beta (β) cells, resulting in severe insulin deficiency. Islet transplantation is a β-cell replacement therapeutic option that aims to restore glycemic control in patients with type 1 diabetes. The objective of this study was to determine the clinical effectiveness of islet transplantation in patients with type 1 diabetes, with or without kidney disease. Methods We conducted a systematic review of the literature on islet transplantation for type 1 diabetes, including relevant health technology assessments, systematic reviews, meta-analyses, and observational studies. We used a two-step process: first, we searched for systematic reviews and health technology assessments; second, we searched primary studies to update the chosen health technology assessment. The Assessment of Multiple Systematic Reviews measurement tool was used to examine the methodological quality of the systematic reviews and health technology assessments. We assessed the quality of the body of evidence and the risk of bias according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. Results Our searched yielded 1,354 citations. One health technology assessment, 11 additional observational studies to update the health technology assessment, one registry report, and four guidelines were included; the observational studies examined islet transplantation alone, islet-after-kidney transplantation, and simultaneous islet-kidney transplantation. In general, low to very low quality of evidence exists for islet transplantation in patients with type 1 diabetes with difficult-to-control blood glucose levels, with or without kidney disease, for these outcomes: health-related quality of life, secondary complications of diabetes, glycemic control, and adverse events. However, high quality of evidence exists for the specific glycemic control outcome of insulin independence compared with intensive insulin therapy. For patients without kidney disease, islet transplantation improves glycemic control and diabetic complications for patients with type 1 diabetes when compared with intensive insulin therapy. However, results for health-related quality of life outcomes were mixed, and adverse events were increased compared with intensive insulin therapy. For patients with type 1 diabetes with kidney disease, islet-after-kidney transplantation or simultaneous islet-kidney transplantation also improved glycemic control and secondary diabetic complications, although the evidence was more limited for this patient group. Compared with intensive insulin therapy, adverse events for islet-after-kidney transplantation or simultaneous islet-kidney transplantation were increased, but were in general less severe than with whole pancreas transplantation. Conclusions For patients with type 1 diabetes with difficult-to-control blood glucose levels, islet transplantation may be a beneficial β-cell replacement therapy to improve glycemic control and secondary complications of diabetes. However, there is uncertainty in the estimates of effectiveness because of the generally low to very low quality of evidence for all outcomes of interest. PMID:26644812

Possible role for fundus autofluorescence as a predictive factor for visual acuity recovery after epiretinal membrane surgery.

PubMed

Brito, Pedro N; Gomes, Nuno L; Vieira, Marco P; Faria, Pedro A; Fernandes, Augusto V; Rocha-Sousa, Amândio; Falcão-Reis, Fernando

2014-02-01

To study the potential association between fundus autofluorescence, spectral-domain optical coherence tomography, and visual acuity in patients undergoing surgery because of epiretinal membranes. Prospective, interventional case series including 26 patients submitted to vitrectomy because of symptomatic epiretinal membranes. Preoperative evaluation consisted of a complete ophthalmologic examination, autofluorescence, and spectral-domain optical coherence tomography. Studied variables included foveal autofluorescence (fov.AF), photoreceptor inner segment/outer segment (IS/OS) junction line integrity, external limiting membrane integrity, central foveal thickness, and foveal morphology. All examinations were repeated at the first, third, and sixth postoperative months. The main outcome measures were logarithm of minimal angle resolution visual acuity, fov.AF integrity, and IS/OS integrity. All cases showing a continuous IS/OS line had an intact fov.AF, whereas patients with IS/OS disruption could have either an increased area of foveal hypoautofluorescence or an intact fov.AF, with the latter being associated with IS/OS integrity recovery in follow-up spectral-domain optical coherence tomography imaging. The only preoperative variables presenting a significant correlation with final visual acuity were baseline visual acuity (P = 0.047) and fov.AF grade (P = 0.023). Recovery of IS/OS line integrity after surgery, in patients with preoperative IS/OS disruption and normal fov.AF, can be explained by the presence of a functional retinal pigment epithelium-photoreceptor complex, supporting normal photoreceptor activity. Autofluorescence imaging provides a functional component to the study of epiretinal membranes, complementing the structural information obtained with optical coherence tomography.

Comparison of auto-fluorescence and tetracycline fluorescence for guided bone surgery of medication-related osteonecrosis of the jaw: a randomized controlled feasibility study.

PubMed

Ristow, O; Otto, S; Geiß, C; Kehl, V; Berger, M; Troeltzsch, M; Koerdt, S; Hohlweg-Majert, B; Freudlsperger, C; Pautke, C

2017-02-01

Recent studies have indicated that bone shows auto-fluorescence under an appropriate fluorescence lamp. The aim of this preliminary study was to compare the success rates of the established tetracycline fluorescence-guided bone surgery with auto-fluorescence-guided bone surgery in the treatment of medication-related osteonecrosis of the jaw (MRONJ). Forty patients suffering from MRONJ were referred for surgical treatment and were divided randomly into two groups: auto-fluorescence (n=20) or tetracycline fluorescence (n=20) guided bone surgery. The primary endpoint was treatment success, defined as the absence of exposed bone at 8 weeks after surgery. Secondary outcomes assessed were mucosal integrity, signs of infection, pain, and loss of sensitivity; these were evaluated descriptively at 10 days, 8 weeks, 6 months, and 1 year after surgery. At 8 weeks postoperative, 18/20 patients (90%) in the auto-fluorescence group and 17/20 patients (85%) in the tetracycline fluorescence group showed mucosal integrity (P>0.05). At the last follow-up, 94% in the auto-fluorescence group and 89% in the tetracycline fluorescence group presented complete mucosal coverage with no exposed bone, infection, or pain (P>0.05). There was no significant difference between the two techniques for any of the secondary outcomes (P>0.05). The results of this preliminary study show that auto-fluorescence-guided bone surgery has comparable success rates to the established tetracycline fluorescence-guided bone surgery. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Intraoperative Near-infrared Imaging for Parathyroid Gland Identification by Auto-fluorescence: A Feasibility Study.

PubMed

De Leeuw, Frederic; Breuskin, Ingrid; Abbaci, Muriel; Casiraghi, Odile; Mirghani, Haïtham; Ben Lakhdar, Aïcha; Laplace-Builhé, Corinne; Hartl, Dana

2016-09-01

Parathyroid glands (PGs) can be particularly hard to distinguish from surrounding tissue and thus can be damaged or removed during thyroidectomy. Postoperative hypoparathyroidism is the most common complication after thyroidectomy. Very recently, it has been found that the parathyroid tissue shows near-infrared (NIR) auto-fluorescence which could be used for intraoperative detection, without any use of contrast agents. The work described here presents a histological validation ex vivo of the NIR imaging procedure and evaluates intraoperative PG detection by NIR auto-fluorescence using for the first time to our knowledge a commercially available clinical NIR imaging device. Ex vivo study on resected operative specimens combined with a prospective in vivo study of consecutive patients who underwent total or partial thyroid, or parathyroid surgery at a comprehensive cancer center. During surgery, any tissue suspected to be a potential PG by the surgeon was imaged with the Fluobeam 800 (®) system. NIR imaging was compared to conventional histology (ex vivo) and/or visual identification by the surgeon (in vivo). We have validated NIR auto-fluorescence with an ex vivo study including 28 specimens. Sensitivity and specificity were 94.1 and 80 %, respectively. Intraoperative NIR imaging was performed in 35 patients and 81 parathyroids were identified. In 80/81 cases, the fluorescence signal was subjectively obvious on real-time visualization. We determined that PG fluorescence is 2.93 ± 1.59 times greater than thyroid fluorescence in vivo. Real-time NIR imaging based on parathyroid auto-fluorescence is fast, safe, and non-invasive and shows very encouraging results, for intraoperative parathyroid identification.

Autofluorescence diagnostic of gynecological diseases ex vivo

NASA Astrophysics Data System (ADS)

Zuev, Vladimir M.; Beliaeva, Ludmila A.; Tevlina, Ekaterina V.; Zaiceva, Galina U.; Loschenov, Victor B.; Stratonnikov, Alexander A.; Volkova, Anna I.

2001-01-01

The method of autofluorescence diagnostic has been applied to study the diseases of uterus and ovaries including tumor of uterus, ovaries and endometriosis. The fluorescence emission spectra of native samples were measured using fiber optics spectrometer. The very high fluorescence in cystic ovaries and tumor ovaries has been observed allowing one to hope that endogenous fluorochromes may play a role of photosensitizes light irradiation.

Light-induced autofluorescence of animal skin used in tissue optical modeling

NASA Astrophysics Data System (ADS)

Borisova, E.; Bliznakova, I.; Troyanova, P.; Avramov, L.

2007-07-01

Light-induced autofluorescence spectroscopy provides many possibilities for medical diagnostics needs for differentiation of tissue pathologies including cancer. For the needs of clinical practice scientists collect spectral data from patients in vivo or they study different tumor models to obtain objective information for fluorescent properties of every kind of normal and diseased tissue. Therefore it is very important to find the most appropriate and close to the human skin samples from the point of view of laser-induced fluorescence spectroscopy, which will give the possibility for easier transfer of data obtained in animal models to spectroscopic medical diagnostics in humans. In this study are presented some results for in vitro detection of the autofluorescence signals of the animal skin (pig and chicken) with using of LEDs as excitation sources (maximum emission at 365, 375, 385 and 400 nm). The autofluorescence signals from in vivo human skin were also detected for comparison with the models' results. Specific features of the spectra measured are discussed and there are proposed some of the origins of the fluorescence signals obtained. Fluorescence maxima detected are addressed to the typical fluorophores existing in the cutaneous tissues. Influence of main skin absorbers, namely melanin and hemoglobin, is also discussed.

Quantitative Characteristics of Spectral-Domain Optical Coherence Tomography in Corresponding Areas of Increased Autofluorescence at the Margin of Geographic Atrophy in Patients With Age-Related Macular Degeneration.

PubMed

Hariri, Amir H; Nittala, Muneeswar G; Sadda, SriniVas R

2016-06-01

To evaluate the spectral-domain optical coherence tomography (SD-OCT) characteristics of the junctional zone corresponding to areas of increased autofluorescence (IAF) at the margin of geographic atrophy (GA) in patients with age-related macular degeneration (AMD). SD-OCT and fundus autofluorescence (FAF) images from untreated eyes with GA available from archived studies at Doheny Image Reading Center were evaluated. Areas of definite decreased autofluorescence (DDAF) corresponding to GA, and areas of IAF at the margins of the GA were manually segmented. Eyes with evidence of IAF were selected. Following manual registration of FAF and OCT data, areas of IAF and normal fluorescence were correlated with OCT features at these locations. Thirty eyes were included. The mean retinal pigment epithelium (RPE) thickness in areas of IAF was 40.6 µm ± 7.69 µm, compared to 28.8 µm ± 7.09 µm in normal adjacent areas (P < .001). Regions of IAF at the junctional zone of GA lesions appear to correspond to thickening of the presumed RPE band on OCT. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:523-527.]. Copyright 2016, SLACK Incorporated.

Wide-field spectral imaging of human ovary autofluorescence and oncologic diagnosis via previously collected probe data

NASA Astrophysics Data System (ADS)

Renkoski, Timothy E.; Hatch, Kenneth D.; Utzinger, Urs

2012-03-01

With no sufficient screening test for ovarian cancer, a method to evaluate the ovarian disease state quickly and nondestructively is needed. The authors have applied a wide-field spectral imager to freshly resected ovaries of 30 human patients in a study believed to be the first of its magnitude. Endogenous fluorescence was excited with 365-nm light and imaged in eight emission bands collectively covering the 400- to 640-nm range. Linear discriminant analysis was used to classify all image pixels and generate diagnostic maps of the ovaries. Training the classifier with previously collected single-point autofluorescence measurements of a spectroscopic probe enabled this novel classification. The process by which probe-collected spectra were transformed for comparison with imager spectra is described. Sensitivity of 100% and specificity of 51% were obtained in classifying normal and cancerous ovaries using autofluorescence data alone. Specificity increased to 69% when autofluorescence data were divided by green reflectance data to correct for spatial variation in tissue absorption properties. Benign neoplasm ovaries were also found to classify as nonmalignant using the same algorithm. Although applied ex vivo, the method described here appears useful for quick assessment of cancer presence in the human ovary.

Sensitivity and specificity of monochromatic photography of the ocular fundus in differentiating optic nerve head drusen and optic disc oedema: optic disc drusen and oedema.

PubMed

Gili, Pablo; Flores-Rodríguez, Patricia; Yangüela, Julio; Orduña-Azcona, Javier; Martín-Ríos, María Dolores

2013-03-01

Evaluation of the efficacy of monochromatic photography of the ocular fundus in differentiating optic nerve head drusen (ONHD) and optic disc oedema (ODE). Sixty-six patients with ONHD, 31 patients with ODE and 70 healthy subjects were studied. Colour and monochromatic fundus photography with different filters (green, red and autofluorescence) were performed. The results were analysed blindly by two observers. The sensitivity, specificity and interobserver agreement (k) of each test were assessed. Colour photography offers 65.5 % sensitivity and 100 % specificity for the diagnosis of ONHD. Monochromatic photography improves sensitivity and specificity and provides similar results: green filter (71.20 % sensitivity, 96.70 % specificity), red filter (80.30 % sensitivity, 96.80 % specificity), and autofluorescence technique (87.8 % sensitivity, 100 % specificity). The interobserver agreement was good with all techniques used: autofluorescence (k = 0.957), green filter (k = 0.897), red filter (k = 0.818) and colour (k = 0.809). Monochromatic fundus photography permits ONHD and ODE to be differentiated, with good sensitivity and very high specificity. The best results were obtained with autofluorescence and red filter study.

Comparison of Fundus Autofluorescence Between Fundus Camera and Confocal Scanning Laser Ophthalmoscope–based Systems

PubMed Central

Park, Sung Pyo; Siringo, Frank S.; Pensec, Noelle; Hong, In Hwan; Sparrow, Janet; Barile, Gaetano; Tsang, Stephen H.; Chang, Stanley

2015-01-01

BACKGROUND AND OBJECTIVE To compare fundus autofluorescence (FAF) imaging via fundus camera (FC) and confocal scanning laser ophthalmoscope (cSLO). PATIENTS AND METHODS FAF images were obtained with a digital FC (530 to 580 nm excitation) and a cSLO (488 nm excitation). Two authors evaluated correlation of autofluorescence pattern, atrophic lesion size, and image quality between the two devices. RESULTS In 120 eyes, the autofluorescence pattern correlated in 86% of lesions. By lesion subtype, correlation rates were 100% in hemorrhage, 97% in geographic atrophy, 82% in flecks, 75% in drusen, 70% in exudates, 67% in pigment epithelial detachment, 50% in fibrous scars, and 33% in macular hole. The mean lesion size in geographic atrophy was 4.57 ± 2.3 mm2 via cSLO and 3.81 ± 1.94 mm2 via FC (P < .0001). Image quality favored cSLO in 71 eyes. CONCLUSION FAF images were highly correlated between the FC and cSLO. Differences between the two devices revealed contrasts. Multiple image capture and confocal optics yielded higher image contrast with the cSLO, although acquisition and exposure time was longer. PMID:24221461

Portable LED-induced autofluorescence spectroscopy for oral cancer diagnosis

NASA Astrophysics Data System (ADS)

Yan, Yung-Jhe; Huang, Ting-Wei; Cheng, Nai-Lun; Hsieh, Yao-Fang; Tsai, Ming-Hsui; Chiou, Jin-Chern; Duann, Jeng-Ren; Lin, Yung-Jiun; Yang, Chin-Siang; Ou-Yang, Mang

2017-04-01

Oral cancer is a serious and growing problem in many developing and developed countries. To improve the cancer screening procedure, we developed a portable light-emitting-diode (LED)-induced autofluorescence (LIAF) imager that contains two wavelength LED excitation light sources and multiple filters to capture ex vivo oral tissue autofluorescence images. Compared with conventional means of oral cancer diagnosis, the LIAF imager is a handier, faster, and more highly reliable solution. The compact design with a tiny probe allows clinicians to easily observe autofluorescence images of hidden areas located in concave deep oral cavities. The ex vivo trials conducted in Taiwan present the design and prototype of the portable LIAF imager used for analyzing 31 patients with 221 measurement points. Using the normalized factor of normal tissues under the excitation source with 365 nm of the central wavelength and without the bandpass filter, the results revealed that the sensitivity was larger than 84%, the specificity was not smaller than over 76%, the accuracy was about 80%, and the area under curve of the receiver operating characteristic (ROC) was achieved at about 87%, respectively. The fact shows the LIAF spectroscopy has the possibilities of ex vivo diagnosis and noninvasive examinations for oral cancer.

pH imaging of mouse kidneys in vivo using a frequency-dependent paraCEST agent.

PubMed

Wu, Yunkou; Zhang, Shanrong; Soesbe, Todd C; Yu, Jing; Vinogradov, Elena; Lenkinski, Robert E; Sherry, A Dean

2016-06-01

This study explored the feasibility of using a pH responsive paramagnetic chemical exchange saturation transfer (paraCEST) agent to image the pH gradient in kidneys of healthy mice. CEST signals were acquired on an Agilent 9.4 Tesla small animal MRI system using a steady-state gradient echo pulse sequence after a bolus injection of agent. The magnetic field inhomogeneity across each kidney was corrected using the WASSR method and pH maps were calculated by measuring the frequency of water exchange signal arising from the agent. Dynamic CEST studies demonstrated that the agent was readily detectable in kidneys only between 4 to 12 min postinjection. The CEST images showed a higher signal intensity in the pelvis and calyx regions and lower signal intensity in the medulla and cortex regions. The pH maps reflected tissue pH values spanning from 6.0 to 7.5 in kidneys of healthy mice. This study demonstrated that pH maps of the kidney can be imaged in vivo by measuring the pH-dependent chemical shift of a single water exchange CEST peak without prior knowledge of the agent concentration in vivo. The results demonstrate the potential of using a simple frequency-dependent paraCEST agent for mapping tissue pH in vivo. Magn Reson Med 75:2432-2441, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Significance of technetium-99m human serum albumin diethylenetriamine pentaacetic acid scintigraphy in patients with nephrotic syndrome.

PubMed

Takashima, Tsuyoshi; Kishi, Tomoya; Onozawa, Koji; Rikitake, Shuichi; Miyazono, Motoaki; Otsuka, Takateru; Irie, Hiroyuki; Iwakiri, Ryuichi; Fujimoto, Kazuma; Ikeda, Yuji

2015-01-01

It is thought that a large amount of albumin leaking from the glomerulus in nephrotic syndrome (NS) is reabsorbed at the proximal tubule and catabolized. Therefore, it is possible the final quantity of urinary protein does not always reflect the amount of leakage of protein from the glomerulus. We experienced two cases without nephrotic range proteinuria thought to involve hypoproteinemia due to the same pathophysiology as NS. On these patients, we performed protein leakage scintigraphy with technetium-99m human serum albumin diethylenetriamine pentaacetic acid (99mTc-HSAD) to exclude a diagnosis of protein-losing gastroenteropathy and observed diffuse positive accumulation in the kidneys with more intense uptake in the kidney than the liver on the anterior view 24 hours after 99mTc-HSAD administration. In healthy adults intravenously given 99mTc-HSAD, the same dynamics are observed as in albumin metabolism, and the organ radioactivity of the liver and kidneys after 24 hours is equal. Therefore, we thought it was possible that the renal uptake 24 hours after 99mTc-HSAD administration was a characteristic finding of NS. In order to confirm it, the subjects were divided into two groups: the NS group (n = 10) and the non-NS group (n = 7). We defined more intense uptake in the kidney than the liver on the anterior view 24 hours after 99mTc-HSAD administration as Dense Kidney (+). Furthermore, we designed regions of interest in the right and left kidneys and liver on anterior and posterior images, then calculated the kidney-liver ratio. Nine of the ten patients had Dense Kidney (+) in the NS group, compared to none in the non-NS group. And the kidney-liver ratio was significantly higher in the NS group than in the non-NS group on each view in the bilateral kidneys. In conclusion, our results suggest that the renal uptake 24 hours after 99mTc-HSAD administration is a characteristic finding of NS.

Recurrence and Treatment after Renal Transplantation in Children with FSGS

PubMed Central

Ha, Il-Soo

2016-01-01

Focal segmental glomerulosclerosis (FSGS) is a common cause of end-stage renal disease and a common pathologic diagnosis of idiopathic nephrotic syndrome (NS), especially in steroid-resistant cases. FSGS is known to recur after kidney transplantation, frequently followed by graft loss. However, not all patients with FSGS suffer from recurrence after kidney transplantation, and genetic and secondary FSGS have a negligible risk of recurrence. Furthermore, many cases of recurrence achieve remission with the current management of recurrence (intensive plasmapheresis/immunosuppression, including rituximab), and other promising agents are being evaluated. Therefore, a pathologic diagnosis of FSGS itself should not cause postponement of allograft kidney transplantation. For patients with a high risk of recurrence who presented with classical symptoms of NS, that is, severe edema, proteinuria, and hypoalbuminemia, close monitoring of proteinuria is necessary, followed by immediate, intensive treatment for recurrence. PMID:27213154

Autofluorescence of normal and neoplastic human brain tissue: an aid for intraoperative delineation of tumor resection margins

NASA Astrophysics Data System (ADS)

Bottiroli, Giovanni F.; Croce, Anna C.; Locatelli, Donata; Nano, Rosanna; Giombelli, Ermanno; Messina, Alberto; Benericetti, Eugenio

1998-01-01

Light-induced autofluorescence measurements were made on normal and tumor brain tissues to assess their spectroscopic properties and to verify the potential of this parameter for an intraoperative delineation of tumor resection margins. Spectrofluorometric analysis was performed both at the microscope on tissue sections from surgical resection, and on patients affected by glioblastoma, during surgical operation. Significant differences in autofluorescence emission properties were found between normal and tumor tissues in both ex vivo and in vivo measurements, indicating that the lesion can be distinguished from the informal surrounding tissues by the signal amplitude and the spectral shape. The non-invasiveness of the technique opens interesting prospects for improving the efficacy of neurosurgical operation, by allowing an intraoperative delimitation of tumor resection margins.

Hyperspectral microscopy can detect metabolic heterogeneity within bovine post-compaction embryos incubated under two oxygen concentrations (7% versus 20%).

PubMed

Sutton-McDowall, Melanie L; Gosnell, Martin; Anwer, Ayad G; White, Melissa; Purdey, Malcolm; Abell, Andrew D; Goldys, Ewa M; Thompson, Jeremy G

2017-10-01

Can we separate embryos cultured under either 7% or 20% oxygen atmospheres by measuring their metabolic heterogeneity? Metabolic heterogeneity and changes in metabolic profiles in morula exposed to two different oxygen concentrations were not detectable using traditional fluorophore and two-channel autofluorescence but were detectable using hyperspectral microscopy. Increased genetic and morphological blastomere heterogeneity is associated with compromised developmental competence of embryos and currently forms the basis for embryo scoring within the clinic. However, there remains uncertainty over the accuracy of current techniques, such as PGS and time-lapse microscopy, to predict subsequent pregnancy establishment. The impact of two oxygen concentrations (7% = optimal and 20% = stressed) during post-fertilisation embryo culture was assessed. Cattle embryos were exposed to the different oxygen concentrations for 8 days (D8; embryo developmental competence) or 5 days (D5; metabolism measurements). Between 3 and 4 experimental replicates were performed, with 40-50 embryos per replicate used for the developmental competency experiment, 10-20 embryos per replicate for the fluorophore and two-channel autofluorescence experiments and a total of 21-22 embryos used for the hyperspectral microscopy study. In-vitro produced (IVP) cattle embryos were utilised for this study. Post-fertilisation, embryos were exposed to 7% or 20% oxygen. To determine impact of oxygen concentrations on embryo viability, blastocyst development was assessed on D8. On D5, metabolic heterogeneity was assessed in morula (on-time) embryos using fluorophores probes (active mitochondria, hydrogen peroxide and reduced glutathione), two-channel autofluorescence (FAD and NAD(P)H) and 18-channel hyperspectral microscopy. Exposure to 20% oxygen following fertilisation significantly reduced total blastocyst, expanded and hatched blastocyst rates by 1.4-, 1.9- and 2.8-fold, respectively, compared to 7% oxygen (P < 0.05), demonstrating that atmospheric oxygen was a viable model for studying mild metabolic stress. The metabolic profiles of D5 embryos was determined and although metabolic heterogeneity was evident within the cleavage stage (i.e. arrested) embryos exposed to fluorophores, there were no detectable difference in fluorescence intensity and pattern localisation in morula exposed to the two different oxygen concentrations (P > 0.05). While there were no significant differences in two-channel autofluorescent profiles of morula exposed to 7% and 20% oxygen (main effect, P > 0.05), morula that subsequently progressed to the blastocyst stage had significantly higher levels of FAD and NAD(P)H fluorescence compared to arrested morula (P < 0.05), with no change in the redox ratio. Hyperspectral autofluorescence imaging (in 18-spectral channels) of the D5 morula revealed highly significant differences in four features of the metabolic profiles of morula exposed to the two different oxygen concentrations (P < 0.001). These four features were weighted and their linear combination revealed clear discrimination between the two treatment groups. Metabolic profiles were assessed at a single time point (morula), and as such further investigation is required to determine if differences in hyperspectral signatures can be detected in pre-compaction embryos and oocytes, using both cattle and subsequently human models. Furthermore, embryo transfers should be performed to determine the relationship between metabolic profiles and pregnancy success. Advanced autofluorescence imaging techniques, such as hyperspectral microscopy, may provide clinics with additional tools to improve the assessment of embryos prior to transfer. This study was funded by the Australian Research Council Centre of Excellence for Nanoscale BioPhotonics (CE140100003). The Fluoview FV10i confocal microscope was purchased as part of the Sensing Technologies for Advanced Reproductive Research (STARR) facility, funded by the South Australian Premier's Science and Research Fund. The authors declare there are no conflict of interest. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Multiparametric Quantitative Ultrasound Imaging in Assessment of Chronic Kidney Disease.

PubMed

Gao, Jing; Perlman, Alan; Kalache, Safa; Berman, Nathaniel; Seshan, Surya; Salvatore, Steven; Smith, Lindsey; Wehrli, Natasha; Waldron, Levi; Kodali, Hanish; Chevalier, James

2017-11-01

To evaluate the value of multiparametric quantitative ultrasound imaging in assessing chronic kidney disease (CKD) using kidney biopsy pathologic findings as reference standards. We prospectively measured multiparametric quantitative ultrasound markers with grayscale, spectral Doppler, and acoustic radiation force impulse imaging in 25 patients with CKD before kidney biopsy and 10 healthy volunteers. Based on all pathologic (glomerulosclerosis, interstitial fibrosis/tubular atrophy, arteriosclerosis, and edema) scores, the patients with CKD were classified into mild (no grade 3 and <2 of grade 2) and moderate to severe (at least 2 of grade 2 or 1 of grade 3) CKD groups. Multiparametric quantitative ultrasound parameters included kidney length, cortical thickness, pixel intensity, parenchymal shear wave velocity, intrarenal artery peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index. We tested the difference in quantitative ultrasound parameters among mild CKD, moderate to severe CKD, and healthy controls using analysis of variance, analyzed correlations of quantitative ultrasound parameters with pathologic scores and the estimated glomerular filtration rate (GFR) using Pearson correlation coefficients, and examined the diagnostic performance of quantitative ultrasound parameters in determining moderate CKD and an estimated GFR of less than 60 mL/min/1.73 m 2 using receiver operating characteristic curve analysis. There were significant differences in cortical thickness, pixel intensity, PSV, and EDV among the 3 groups (all P < .01). Among quantitative ultrasound parameters, the top areas under the receiver operating characteristic curves for PSV and EDV were 0.88 and 0.97, respectively, for determining pathologic moderate to severe CKD, and 0.76 and 0.86 for estimated GFR of less than 60 mL/min/1.73 m 2 . Moderate to good correlations were found for PSV, EDV, and pixel intensity with pathologic scores and estimated GFR. The PSV, EDV, and pixel intensity are valuable in determining moderate to severe CKD. The value of shear wave velocity in assessing CKD needs further investigation. © 2017 by the American Institute of Ultrasound in Medicine.

Estimated GFR and the Effect of Intensive Blood Pressure Lowering After Acute Intracerebral Hemorrhage.

PubMed

Zheng, Danni; Sato, Shoichiro; Arima, Hisatomi; Heeley, Emma; Delcourt, Candice; Cao, Yongjun; Chalmers, John; Anderson, Craig S

2016-07-01

The kidney-brain interaction has been a topic of growing interest. Past studies of the effect of kidney function on intracerebral hemorrhage (ICH) outcomes have yielded inconsistent findings. Although the second, main phase of the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial (INTERACT2) suggests the effectiveness of early intensive blood pressure (BP) lowering in improving functional recovery after ICH, the balance of potential benefits and harms of this treatment in those with decreased kidney function remains uncertain. Secondary analysis of INTERACT2, which randomly assigned patients with ICH with elevated systolic BP (SBP) to intensive (target SBP<140mmHg) or contemporaneous guideline-based (target SBP<180mmHg) BP management. 2,823 patients from 144 clinical hospitals in 21 countries. Admission estimated glomerular filtration rates (eGFRs) of patients were categorized into 3 groups based on the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine equation: normal or high, mildly decreased, and moderately to severely decreased (>90, 60-90, and <60mL/min/1.73m(2), respectively). The effect of admission eGFR on the primary outcome of death or major disability at 90 days (defined as modified Rankin Scale scores of 3-6) was analyzed using a multivariable logistic regression model. Potential effect modification of intensive BP lowering treatment by admission eGFR was assessed by interaction terms. Of 2,623 included participants, 912 (35%) and 280 (11%) had mildly and moderately/severely decreased eGFRs, respectively. Patients with moderately/severely decreased eGFRs had the greatest risk for death or major disability at 90 days (adjusted OR, 1.82; 95% CI, 1.28-2.61). Effects of early intensive BP lowering were consistent across different eGFRs (P=0.5 for homogeneity). Generalizability issues arising from a clinical trial population. Decreased eGFR predicts poor outcome in acute ICH. Early intensive BP lowering provides similar treatment effects in patients with ICH with decreased eGFRs. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Ex vivo applications of multiphoton microscopy in urology

NASA Astrophysics Data System (ADS)

Jain, Manu; Mukherjee, Sushmita

2016-03-01

Background: Routine urological surgery frequently requires rapid on-site histopathological tissue evaluation either during biopsy or intra-operative procedure. However, resected tissue needs to undergo processing, which is not only time consuming but may also create artifacts hindering real-time tissue assessment. Likewise, pathologist often relies on several ancillary methods, in addition to H&E to arrive at a definitive diagnosis. Although, helpful these techniques are tedious and time consuming and often show overlapping results. Therefore, there is a need for an imaging tool that can rapidly assess tissue in real-time at cellular level. Multiphoton microscopy (MPM) is one such technique that can generate histology-quality images from fresh and fixed tissue solely based on their intrinsic autofluorescence emission, without the need for tissue processing or staining. Design: Fresh tissue sections (neoplastic and non-neoplastic) from biopsy and surgical specimens of bladder and kidney were obtained. Unstained deparaffinized slides from biopsy of medical kidney disease and oncocytic renal neoplasms were also obtained. MPM images were acquired using with an Olympus FluoView FV1000MPE system. After imaging, fresh tissues were submitted for routine histopathology. Results: Based on the architectural and cellular details of the tissue, MPM could characterize normal components of bladder and kidney. Neoplastic tissue could be differentiated from non-neoplastic tissue and could be further classified as per histopathological convention. Some of the tumors had unique MPM signatures not otherwise seen on H&E sections. Various subtypes of glomerular lesions were identified as well as renal oncocytic neoplasms were differentiated on unstained deparaffinized slides. Conclusions: We envision MPM to become an integral part of regular diagnostic workflow for rapid assessment of tissue. MPM can be used to evaluate the adequacy of biopsies and triage tissues for ancillary studies. It can also be used as an adjunct to frozen section analysis for intra-operative margin assessment. Further, it can play an important role for pathologist for guiding specimen grossing, selecting tissue for tumor banking and as a rapid ancillary diagnostic tool.

Uric acid and progression of chronic kidney disease.

PubMed

Weaver, Donald J

2018-06-21

The association between serum uric acid levels and human disease has garnered intense interest over the last decade including chronic kidney disease. Animal studies have provided evidence for a potential mechanistic role of uric acid in promoting progression of chronic kidney disease. Epidemiologic studies have also suggested an association between elevated serum uric acid levels and worsening renal function in the general population as well as in patients with chronic kidney disease. However, there is currently insufficient evidence to recommend the use of uric acid-lowering therapy to delay progression of chronic kidney disease in this patient population. Adequately powered, randomized, placebo-controlled trials are required to more precisely evaluate the risk and benefits of uric acid-lowering therapy in pediatric patients.

Fluorescence lifetime spectroscopy: potential for in-vivo estimation of skin fluorophores changes after low power laser treatment

NASA Astrophysics Data System (ADS)

Ferulova, Inesa; Lihachev, Alexey; Spigulis, Janis

2013-11-01

The impact of visible cwlaser irradiation on skin autofluorescence lifetimes was investigated in spectral range from 450 nm to 600 nm. Skin optical provocations were performed during 1 min by 405 nm low power cw laser with power density up to 20 mW/cm2. Autofluorescence lifetimes were measured before and immediately after the optical provocation.

NEAR-INFRARED AUTOFLUORESCENCE IN BILATERAL DIFFUSE UVEAL MELANOCYTIC PROLIFERATION ASSOCIATED WITH ESOPHAGEAL CARCINOMA AND CHOROIDAL METASTASIS.

PubMed

Golshahi, Azadeh; Bornfeld, Norbert; Weinitz, Silke; Kellner, Ulrich

2016-01-01

To investigate the advantage of near-infrared autofluorescence (787 nm) for the detection of melanocytic lesions in a patient with bilateral diffuse uveal melanocytic proliferation in association with esophageal carcinoma complicated by most likely unilateral choroidal metastasis. In this retrospective case report, a 55-year-old woman referred for the evaluation of sudden visual loss underwent normal ophthalmological evaluation and, in addition, was examined with near-infrared reflectance, near-infrared autofluorescence, fundus autofluorescence (Heidelberg Retina Angiograph II [HRA2; Heidelberg Engineering]), spectral domain optical coherence tomography (Spectralis OCT; Heidelberg Engineering), and multifocal electroretinography (RetiScan; Roland Consult). The patient had been diagnosed with esophageal carcinoma 3 months before the onset of visual symptoms. The visual acuity was 20/40 in the right eye and 20/20 in the left eye. Bilateral patchy melanocytic proliferation was detected on ophthalmoscopy. The extent of lesions was best detected with near-infrared reflectance and near-infrared autofluorescence, whereas fundus autofluorescence and spectral domain optical coherence tomography did not reveal alterations of the outer retina or retinal pigment epithelium in this early stage of bilateral diffuse uveal melanocytic proliferation. The right eye showed in addition to the findings on the left eye choroidal folds in the fovea and an elevated lesion inferotemporal of the fovea suspicious of a choroidal metastasis. In the B-scan ultrasonography, a homogenous lesion was seen. Spectral domain optical coherence tomography demonstrated a mild accumulation of subretinal fluid adjacent to and over the choroidal metastasis. Transretinal biopsy of this elevated lesion revealed a low differentiated carcinoma of squamous epithelium, compatible with choroidal metastasis of the esophageal carcinoma. The choroidal metastasis increased within 3 months after the first visit. The visual acuity dropped in both eyes. The patient died 6 months after her first visit. Bilateral diffuse uveal melanocytic proliferation can be associated with esophageal carcinoma as a systemic malignancy. Near-infrared imaging can be helpful to detect early stages of BDUMP and can help offer recently reported treatment options at an early stage of disease.

In vivo imaging of the retinal pigment epithelial cells

NASA Astrophysics Data System (ADS)

Morgan, Jessica Ijams Wolfing

The retinal pigment epithelial (RPE) cells form an important layer of the retina because they are responsible for providing metabolic support to the photoreceptors. Techniques to image the RPE layer include autofluorescence imaging with a scanning laser ophthalmoscope (SLO). However, previous studies were unable to resolve single RPE cells in vivo. This thesis describes the technique of combining autofluorescence, SLO, adaptive optics (AO), and dual-wavelength simultaneous imaging and registration to visualize the individual cells in the RPE mosaic in human and primate retina for the first time in vivo. After imaging the RPE mosaic non-invasively, the cell layer's structure and regularity were characterized using quantitative metrics of cell density, spacing, and nearest neighbor distances. The RPE mosaic was compared to the cone mosaic, and RPE imaging methods were confirmed using histology. The ability to image the RPE mosaic led to the discovery of a novel retinal change following light exposure; 568 nm exposures caused an immediate reduction in autofluorescence followed by either full recovery or permanent damage in the RPE layer. A safety study was conducted to determine the range of exposure irradiances that caused permanent damage or transient autofluorescence reductions. Additionally, the threshold exposure causing autofluorescence reduction was determined and reciprocity of radiant exposure was confirmed. Light exposures delivered by the AOSLO were not significantly different than those delivered by a uniform source. As all exposures tested were near or below the permissible light levels of safety standards, this thesis provides evidence that the current light safety standards need to be revised. Finally, with the retinal damage and autofluorescence reduction thresholds identified, the methods of RPE imaging were modified to allow successful imaging of the individual cells in the RPE mosaic while still ensuring retinal safety. This thesis has provided a highly sensitive method for studying the in vivo morphology of individual RPE cells in normal, diseased, and damaged retinas. The methods presented here also will allow longitudinal studies for tracking disease progression and assessing treatment efficacy in human patients and animal models of retinal diseases affecting the RPE.

Enhancing analysis of cells and proteins by fluorescence imaging on silk-based biomaterials: modulating the autofluorescence of silk.

PubMed

Neo, Puay Yong; Tan, Daryl Jian-An; Shi, Pujiang; Toh, Siew Lok; Goh, James Cho-Hong

2015-02-01

Silk is a versatile and established biomaterial for various tissue engineering purposes. However, it also exhibits strong autofluorescence signals-thereby hindering fluorescence imaging analysis of cells and proteins on silk-derived biomaterials. Sudan Black B (SB) is a lysochrome dye commonly used to stain lipids in histology. It has also been reported to be able to quench autofluorescence of tissues in histology and has been tested on artificial biomedical polymers in recent years. It was hypothesized that SB would exert similar quenching effects on silk, modulating the autofluorescence signals, and thereby enabling improved imaging analysis of cells and molecules of interests. The quenching effect of SB on the intrinsic fluorescence properties of silk and on commercial fluorescent dyes were first investigated in this study. SB was then incorporated into typical fluorescence-based staining protocols to study its effectiveness in improving fluorescence-based imaging of the cells and proteins residing with the silk-based biomaterials. Silk processed into various forms of biomaterials (e.g., films, sponges, fibers, and electrospun mats) was seeded with cells and cultured in vitro. At sacrificial time points, specimens were harvested, fixed, and prepared for fluorescence staining. SB, available commercially as a powder, was dissolved in 70% ethanol (0.3% [w/v]) to form staining solutions. SB treatment was introduced at the last step of typical immunofluorescence staining protocols for 15-120 min. For actin staining protocols by phalloidin toxin, SB staining solutions were added before and after permeabilization with Triton-X for 15-30 min. Results showed that ideal SB treatment duration is about 15 min. Apart from being able to suppress the autofluorescence of silk, this treatment duration was also not too long to adversely affect the fluorescent labeling probes used. The relative improvement brought about by SB treatment was most evident in the blue and green emission wavelengths compared with the red emission wavelength. This study has showed that the use of SB is a cost and time effective approach to enhance fluorescence-based imaging analyses of cell-seeded silk biomaterials, which otherwise would have been hindered by the unmodulated autofluorescence signals.

Congenital anatomic variants of the kidney and ureter: a pictorial essay.

PubMed

Srinivas, M R; Adarsh, K M; Jeeson, Riya; Ashwini, C; Nagaraj, B R

2016-03-01

Congenital renal parenchymal and pelvicalyceal abnormalities have a wide spectrum. Most of them are asymptomatic, like that of ectopia, cross fused kidney, horseshoe kidney, etc., while a few of them become complicated, leading to renal failure and death. It is very important for the radiologist to identify these anatomic variants and guide the clinicians for surgical and therapeutic procedures. Cross-sectional imaging with a volume rendered technique/maximum intensity projection has overcome ultrasonography and IVU for identification and interpretation of some of these variants.

Confocal nanoscanning, bead picking (CONA): PickoScreen microscopes for automated and quantitative screening of one-bead one-compound libraries.

PubMed

Hintersteiner, Martin; Buehler, Christof; Uhl, Volker; Schmied, Mario; Müller, Jürgen; Kottig, Karsten; Auer, Manfred

2009-01-01

Solid phase combinatorial chemistry provides fast and cost-effective access to large bead based libraries with compound numbers easily exceeding tens of thousands of compounds. Incubating one-bead one-compound library beads with fluorescently labeled target proteins and identifying and isolating the beads which contain a bound target protein, potentially represents one of the most powerful generic primary high throughput screening formats. On-bead screening (OBS) based on this detection principle can be carried out with limited automation. Often hit bead detection, i.e. recognizing beads with a fluorescently labeled protein bound to the compound on the bead, relies on eye-inspection under a wide-field microscope. Using low resolution detection techniques, the identification of hit beads and their ranking is limited by a low fluorescence signal intensity and varying levels of the library beads' autofluorescence. To exploit the full potential of an OBS process, reliable methods for both automated quantitative detection of hit beads and their subsequent isolation are needed. In a joint collaborative effort with Evotec Technologies (now Perkin-Elmer Cellular Technologies Germany GmbH), we have built two confocal bead scanner and picker platforms PS02 and a high-speed variant PS04 dedicated to automated high resolution OBS. The PS0X instruments combine fully automated confocal large area scanning of a bead monolayer at the bottom of standard MTP plates with semiautomated isolation of individual hit beads via hydraulic-driven picker capillaries. The quantification of fluorescence intensities with high spatial resolution in the equatorial plane of each bead allows for a reliable discrimination between entirely bright autofluorescent beads and real hit beads which exhibit an increased fluorescence signal at the outer few micrometers of the bead. The achieved screening speed of up to 200,000 bead assayed in less than 7 h and the picking time of approximately 1 bead/min allow exploitation of one-bead one-compound libraries with high sensitivity, accuracy, and speed.

Analysis of autofluorescence pattern in birdshot chorioretinopathy.

PubMed

Semécas, R; Mauget-Faÿsse, M; Aptel, F; Mailhac, A; Salmon, L; Vasseur, V; Bouillet, L; Chiquet, C

2017-07-01

To characterize and correlate the different patterns of fundus autofluorescence (FAF) in patients with birdshot chorioretinopathy (BSCR), with functional and anatomical parameters. Twenty-one BSCR patients were prospectively studied in 2013 and 2014. Each patient underwent visual acuity (VA) and visual field (SITA standard 30.2) testing as well as fluorescein and indocyanine green angiography, spectral-domain optical coherence tomography (SD-OCT) B scan, enhanced depth imaging (EDI), and fundus autofluorescence (FAF) imaging. The disease was classified as active, chronic, or quiescent. The patients' mean age was 60.3 ± 9.2 years and 60% were female. Disease duration was 5.7 ± 3.7 years. Autofluorescence imaging showed punctiform hyper-FAF spots in 23 out of the 29 eyes (79%), which was significantly associated with a greater visual field mean deviation (-7 ± 7 versus -3 ± 2 dB, p = 0.04). Hypo-FAF was defined as peripapillary (n = 25; 86.2%), macular (n = 10; 34.5%), lichenoid (n = 17; 58.6%), and/or diffuse (n = 13; 44.8%). Lichenoid hypo-FAF was significantly associated with worse VA (0.18 ± 0.24 vs. 0.05 ± 0.07 LogMAR, p = 0.04). Macular hypo-FAF was associated with a history of macular edema (62.5%; p = 0.06). Diffuse hypo-FAF was observed more frequently (p = 0.01) in chronic disease (66.7%) than in active (0%) or quiescent disease (27.3%). Autofluorescence analysis in BRSC patients contributes to evaluating disease activity and could be useful to guide follow-up and treatment.

Simple non-invasive assessment of advanced glycation endproduct accumulation.

PubMed

Meerwaldt, R; Graaff, R; Oomen, P H N; Links, T P; Jager, J J; Alderson, N L; Thorpe, S R; Baynes, J W; Gans, R O B; Smit, A J

2004-07-01

The accumulation of AGE is thought to play a role in the pathogenesis of chronic complications of diabetes mellitus and renal failure. All current measurements of AGE accumulation require invasive sampling. We exploited the fact that several AGE exhibit autofluorescence to develop a non-invasive tool for measuring skin AGE accumulation, the Autofluorescence Reader (AFR). We validated its use by comparing the values obtained using the AFR with the AGE content measured in extracts from skin biopsies of diabetic and control subjects. Using the AFR with an excitation light source of 300-420 nm, fluorescence of the skin was measured at the arm and lower leg in 46 patients with diabetes (Type 1 and 2) and in 46 age- and sex-matched control subjects, the majority of whom were Caucasian. Autofluorescence was defined as the average fluorescence per nm over the entire emission spectrum (420-600 nm) as ratio of the average fluorescence per nm over the 300-420-nm range. Skin biopsies were obtained from the same site of the arm, and analysed for collagen-linked fluorescence (CLF) and specific AGE: pentosidine, N(epsilon)-(carboxymethyl)lysine (CML) and N(epsilon)-(carboxyethyl)lysine (CEL). Autofluorescence correlated with CLF, pentosidine, CML, and CEL ( r=0.47-0.62, p

Ex-vivo UV autofluorescence imaging and fluorescence spectroscopy of atherosclerotic pathology in human aorta

NASA Astrophysics Data System (ADS)

Lewis, William; Williams, Maura; Franco, Walfre

2017-02-01

The aim of our study was to identify fluorescence excitation-emission pairs correlated with atherosclerotic pathology in ex-vivo human aorta. Wide-field images of atherosclerotic human aorta were captured using UV and visible excitation and emission wavelength pairs of several known fluorophores to investigate correspondence with gross pathologic features. Fluorescence spectroscopy and histology were performed on 21 aortic samples. A matrix of Pearson correlation coefficients were determined for the relationship between relevant histologic features and the intensity of emission for 427 wavelength pairs. A multiple linear regression analysis indicated that elastin (370/460 nm) and tryptophan (290/340 nm) fluorescence predicted 58% of the variance in intima thickness (R-squared = 0.588, F(2,18) = 12.8, p=.0003), and 48% of the variance in media thickness (R-squared = 0.483, F(2,18) = 8.42, p=.002), suggesting that endogenous fluorescence intensity at these wavelengths can be utilized for improved pathologic characterization of atherosclerotic plaques.

Comparing in vivo pump–probe and multiphoton fluorescence microscopy of melanoma and pigmented lesions

PubMed Central

Wilson, Jesse W.; Degan, Simone; Gainey, Christina S.; Mitropoulos, Tanya; Simpson, Mary Jane; Zhang, Jennifer Y.; Warren, Warren S.

2014-01-01

Abstract. We demonstrate a multimodal approach that combines a pump–probe with confocal reflectance and multiphoton autofluorescence microscopy. Pump–probe microscopy has been proven to be of great value in analyzing thin tissue sections of pigmented lesions, as it produces molecular contrast which is inaccessible by other means. However, the higher optical intensity required to overcome scattering in thick tissue leads to higher-order nonlinearities in the optical response of melanin (e.g., two-photon pump and one-photon probe) that present additional challenges for interpreting the data. We show that analysis of pigment composition in vivo must carefully account for signal terms that are nonlinear with respect to the pump and probe intensities. We find that pump–probe imaging gives useful contrast for pigmented structures over a large range of spatial scales (100  μm to 1 cm), making it a potentially useful tool for tracking the progression of pigmented lesions without the need to introduce exogenous contrast agents. PMID:25415567

Design and evaluation of excitation light source device for fluorescence endoscope

NASA Astrophysics Data System (ADS)

Lim, Hyun Soo

2009-06-01

This study aims at designing and evaluating light source devices that can stably generate light with various wavelengths in order to make possible PDD using a photosensitizer and diagnosis using auto-fluorescence. The light source was a Xenon lamp and filter wheel, composed of an optical output control through Iris and filters with several wavelength bands. It also makes the inducement of auto-fluorescence possible because it is designed to generate a wavelength band of 380-420nm, 430-480nm, and 480-560nm. The transmission part of the light source was developed to enhance the efficiency of light transmission. To evaluate this light source, the characteristics of light output and wavelength band were verified. To validate the capability of this device as PDD, the detection of auto-fluorescence using mouse models was performed.

An automated image processing routine for segmentation of cell cytoplasms in high-resolution autofluorescence images

NASA Astrophysics Data System (ADS)

Walsh, Alex J.; Skala, Melissa C.

2014-02-01

The heterogeneity of genotypes and phenotypes within cancers is correlated with disease progression and drug-resistant cellular sub-populations. Therefore, robust techniques capable of probing majority and minority cell populations are important both for cancer diagnostics and therapy monitoring. Herein, we present a modified CellProfiler routine to isolate cytoplasmic fluorescence signal on a single cell level from high resolution auto-fluorescence microscopic images.

Imaging autofluorescence temporal signatures of the human ocular fundus in vivo

NASA Astrophysics Data System (ADS)

Papour, Asael; Taylor, Zachary; Stafsudd, Oscar; Tsui, Irena; Grundfest, Warren

2015-11-01

We demonstrate real-time in vivo fundus imaging capabilities of our fluorescence lifetime imaging technology for the first time. This implementation of lifetime imaging uses light emitting diodes to capture full-field images capable of showing direct tissue contrast without executing curve fitting or lifetime calculations. Preliminary results of fundus images are presented, investigating autofluorescence imaging potential of various retina biomarkers for early detection of macular diseases.

Investigation of in-vivo skin autofluorescence lifetimes under long-term cw optical excitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lihachev, A; Ferulova, I; Vasiljeva, K

2014-08-31

The main results obtained during the last five years in the field of laser-excited in-vivo human skin photobleaching effects are presented. The main achievements and results obtained, as well as methods and experimental devices are briefly described. In addition, the impact of long-term 405-nm cw low-power laser excitation on the skin autofluorescence lifetime is experimentally investigated. (laser biophotonics)

Label-free imaging of Drosophila in vivo by coherent anti-Stokes Raman scattering and two-photon excitation autofluorescence microscopy

NASA Astrophysics Data System (ADS)

Chien, Cheng-Hao; Chen, Wei-Wen; Wu, June-Tai; Chang, Ta-Chau

2011-01-01

Drosophila is one of the most valuable model organisms for studying genetics and developmental biology. The fat body in Drosophila, which is analogous to the liver and adipose tissue in human, stores lipids that act as an energy source during its development. At the early stages of metamorphosis, the fat body remodeling occurs involving the dissociation of the fat body into individual fat cells. Here we introduce a combination of coherent anti-Stokes Raman scattering (CARS) and two-photon excitation autofluorescence (TPE-F) microscopy to achieve label-free imaging of Drosophila in vivo at larval and pupal stages. The strong CARS signal from lipids allows direct imaging of the larval fat body and pupal fat cells. In addition, the use of TPE-F microscopy allows the observation of other internal organs in the larva and autofluorescent globules in fat cells. During the dissociation of the fat body, the findings of the degradation of lipid droplets and an increase in autofluorescent globules indicate the consumption of lipids and the recruitment of proteins in fat cells. Through in vivo imaging and direct monitoring, CARS microscopy may help elucidate how metamorphosis is regulated and study the lipid metabolism in Drosophila.

HYPERSPECTRAL AUTOFLUORESCENCE IMAGING OF DRUSEN AND RETINAL PIGMENT EPITHELIUM IN DONOR EYES WITH AGE-RELATED MACULAR DEGENERATION.

PubMed

Tong, Yuehong; Ben Ami, Tal; Hong, Sungmin; Heintzmann, Rainer; Gerig, Guido; Ablonczy, Zsolt; Curcio, Christine A; Ach, Thomas; Smith, R Theodore

2016-12-01

To elucidate the molecular pathogenesis of age-related macular degeneration (AMD) and interpretation of fundus autofluorescence imaging, the authors identified spectral autofluorescence characteristics of drusen and retinal pigment epithelium (RPE) in donor eyes with AMD. Macular RPE/Bruch membrane flat mounts were prepared from 5 donor eyes with AMD. In 12 locations (1-3 per eye), hyperspectral autofluorescence images in 10-nm-wavelength steps were acquired at 2 excitation wavelengths (λex 436, 480 nm). A nonnegative tensor factorization algorithm was used to recover 5 abundant emission spectra and their corresponding spatial localizations. At λex 436 nm, the authors consistently localized a novel spectrum (SDr) with a peak emission near 510 nm in drusen and sub-RPE deposits. Abundant emission spectra seen previously (S0 in Bruch membrane and S1, S2, and S3 in RPE lipofuscin/melanolipofuscin, respectively) also appeared in AMD eyes, with the same shapes and peak wavelengths as in normal tissue. Lipofuscin/melanolipofuscin spectra localizations in AMD eyes varied widely in their overlap with drusen, ranging from none to complete. An emission spectrum peaking at ∼510 nm (λex 436 nm) appears to be sensitive and specific for drusen and sub-RPE deposits. One or more abundant spectra from RPE organelles exhibit characteristic relationships with drusen.

Wide-field spectral imaging of human ovary autofluorescence and oncologic diagnosis via previously collected probe data

PubMed Central

Hatch, Kenneth D.

2012-01-01

Abstract. With no sufficient screening test for ovarian cancer, a method to evaluate the ovarian disease state quickly and nondestructively is needed. The authors have applied a wide-field spectral imager to freshly resected ovaries of 30 human patients in a study believed to be the first of its magnitude. Endogenous fluorescence was excited with 365-nm light and imaged in eight emission bands collectively covering the 400- to 640-nm range. Linear discriminant analysis was used to classify all image pixels and generate diagnostic maps of the ovaries. Training the classifier with previously collected single-point autofluorescence measurements of a spectroscopic probe enabled this novel classification. The process by which probe-collected spectra were transformed for comparison with imager spectra is described. Sensitivity of 100% and specificity of 51% were obtained in classifying normal and cancerous ovaries using autofluorescence data alone. Specificity increased to 69% when autofluorescence data were divided by green reflectance data to correct for spatial variation in tissue absorption properties. Benign neoplasm ovaries were also found to classify as nonmalignant using the same algorithm. Although applied ex vivo, the method described here appears useful for quick assessment of cancer presence in the human ovary. PMID:22502561

Sensitivity and specificity of detecting reticular pseudodrusen in multimodal imaging in Japanese patients.

PubMed

Ueda-Arakawa, Naoko; Ooto, Sotaro; Tsujikawa, Akitaka; Yamashiro, Kenji; Oishi, Akio; Yoshimura, Nagahisa

2013-03-01

To identify reticular pseudodrusen (RPD) in age-related macular degeneration using multiple imaging modalities, including the blue channel image of fundus photography, infrared reflectance (IR), fundus autofluorescence, near-infrared fundus autofluorescence, confocal blue reflectance, indocyanine green angiography, and spectral-domain optical coherence tomography (SD-OCT), and to compare the sensitivities and specificities of these modalities for detecting RPD. This study included 220 eyes from 114 patients with newly diagnosed age-related macular degeneration. Patients underwent fundus photography, IR, fundus autofluorescence, near-infrared fundus autofluorescence, confocal blue reflectance, indocyanine green angiography, and SD-OCT in both eyes. Eyes were diagnosed with RPD if they showed reticular patterns on at least two of the seven imaging modalities. Thirty-seven eyes were diagnosed with RPD. However, SD-OCT and IR had the highest sensitivity (94.6%), and at the same time, SD-OCT had a high specificity (98.4%). The blue channel of color fundus photography, confocal blue reflectance, and indocyanine green angiography had a specificity of 100% but had lower sensitivity than that of SD-OCT and IR. For detecting RPD, IR and SD-OCT had the highest sensitivity. Although SD-OCT had the highest sensitivity and specificity, RPD detection should be confirmed using more than one modality for increased accuracy.

An accurate homogenized tissue phantom for broad spectrum autofluorescence studies: a tool for optimizing quantum dot-based contrast agents

NASA Astrophysics Data System (ADS)

Roy, Mathieu; Wilson, Brian C.

2008-02-01

We are investigating the use of ZnS-capped CdSe quantum dot (QD) bioconjugates combined with fluorescence endoscopy for improved early cancer detection in the esophagus, colon and lung. A major challenge in using fluorescent contrast agents in vivo is to extract the relevant signal from the tissue autofluorescence (AF). The present studies are aimed at maximizing the QD signal to AF background ratio (SBR) to facilitate detection. These contrast optimization studies require optical phantoms that simulate tissue autofluorescence, absorption and scattering over the entire visible spectrum, while allowing us to control the optical thickness. We present an optical phantom made of fresh homogenized tissue diluted in water. The homogenized tissue is poured into a clear polymer tank designed to hold a QD-loaded silica capillary in its center. Because of the non-linear effects of absorption and scattering on measured autofluorescence, direct comparison between results obtained using tissue phantoms of different concentration is not possible. We introduce mathematical models that make it possible to perform measurements on diluted tissue homogenates and subsequently extrapolate the results to intact (non-diluted) tissue. Finally, we present preliminary QD contrast data showing that the 380-420 nm spectral window is optimal for surface QD imaging.

Raman and Autofluorescence Spectrum Dynamics along the HRG-Induced Differentiation Pathway of MCF-7 Cells

PubMed Central

Morita, Shin-ichi; Takanezawa, Sota; Hiroshima, Michio; Mitsui, Toshiyuki; Ozaki, Yukihiro; Sako, Yasushi

2014-01-01

Cellular differentiation proceeds along complicated pathways, even when it is induced by extracellular signaling molecules. One of the major reasons for this complexity is the highly multidimensional internal dynamics of cells, which sometimes causes apparently stochastic responses in individual cells to extracellular stimuli. Therefore, to understand cell differentiation, it is necessary to monitor the internal dynamics of cells at single-cell resolution. Here, we used a Raman and autofluorescence spectrum analysis of single cells to detect dynamic changes in intracellular molecular components. MCF-7 cells are a human cancer-derived cell line that can be induced to differentiate into mammary-gland-like cells with the addition of heregulin (HRG) to the culture medium. We measured the spectra in the cytoplasm of MCF-7 cells during 12 days of HRG stimulation. The Raman scattering spectrum, which was the major component of the signal, changed with time. A multicomponent analysis of the Raman spectrum revealed that the dynamics of the major components of the intracellular molecules, including proteins and lipids, changed cyclically along the differentiation pathway. The background autofluorescence signals of Raman scattering also provided information about the differentiation process. Using the total information from the Raman and autofluorescence spectra, we were able to visualize the pathway of cell differentiation in the multicomponent phase space. PMID:25418290

Novel Phenotypic and Genotypic Findings in X-Linked Retinoschisis

PubMed Central

Tsang, Stephen H.; Vaclavik, Veronika; Bird, Alan C.; Robson, Anthony G.; Holder, Graham E.

2009-01-01

Objective To describe atypical phenotypes associated with the retinoschisis (X-linked, juvenile) 1 mutation (RS1). Methods Seven patients with multiple fine white dots at the macula and reduced visual acuity were evaluated. Six patients underwent pattern and full-field electroretinography (ERG). On-off ERG, optical coherence tomography, and fundus autofluorescence imaging were performed in some patients. Mutational screening of RS1 was prompted by the ERG findings. Results Fine white dots resembling drusenlike deposits and sometimes associated with retinal pigment epithelial abnormalities were present in the maculae. An electronegative bright-flash ERG configuration was present in all patients tested, and abnormal pattern ERG findings confirmed macular dysfunction. A parafoveal ring of high-density autofluorescence was present in 3 eyes; 1 patient showed high-density foci concordant with the white dots. Optical coherence tomography did not show foveal schisis in 3 of 4 eyes. All patients carried mutations in RS1, including 1 with a novel 206T→C mutation in exon 4. Conclusions Multiple fine white dots at the macula may be the initial fundus feature in RS1 mutation. Electrophysiologic findings suggest dysfunction after phototransduction and enable focused mutational screening. Autofluorescence imaging results suggest early retinal pigment epithelium involvement; a parafoveal ring of high-density autofluorescence has not previously been described in this disorder. PMID:17296904

X-linked juvenile retinoschisis in a consanguineous family: phenotypic variability and report of a homozygous female patient.

PubMed

Gliem, Martin; Holz, Frank G; Stöhr, Heidi; Weber, Bernhard H F; Charbel Issa, Peter

2014-12-01

To describe the phenotypic variability in a consanguineous family with genetically confirmed X-linked retinoschisis. Five patients, including one homozygous female, were characterized by clinical examination, optical coherence tomography, fundus autofluorescence, mapping of macular pigment optical density, electroretinography, and DNA testing. The 36-year-old male index patient showed a ring of enhanced autofluorescence and outer retinal atrophy on optical coherence tomography. Electroretinography testing revealed a reduced a/b ratio. His mother presented with a central atrophic retina with markedly reduced autofluorescence signal and a surrounding ring of enhanced autofluorescence. The 40-year-old brother of the index patient and his 2 sons showed characteristic signs for X-linked retinoschisis, including retinal schisis and a reduced a/b ratio. Genetic testing revealed a c.293C>A mutation in the RS1 gene in all affected family members while the mother of the index patient was homozygous for this mutation. X-linked retinoschisis can present with a wide phenotypic variability. Here, detailed family history and genetic testing established the diagnosis of X-linked retinoschisis despite striking differences in phenotypic presentation in affected subjects, homozygosity of one affected female, and seemingly dominant inheritance in three subsequent generations because of multiple consanguinity.

The Kidney and Periodontal Disease (KAPD) study: A pilot randomized controlled trial testing the effect of non-surgical periodontal therapy on chronic kidney disease.

PubMed

Grubbs, Vanessa; Garcia, Faviola; Jue, Bonnie L; Vittinghoff, Eric; Ryder, Mark; Lovett, David; Carrillo, Jacqueline; Offenbacher, Steven; Ganz, Peter; Bibbins-Domingo, Kirsten; Powe, Neil R

2017-02-01

Chronic kidney disease (CKD) remains a prevalent public health problem that disproportionately affects minorities and the poor, despite intense efforts targeting traditional risk factors. Periodontal diseases are common bacterial plaque-induced inflammatory conditions that can respond to treatment and have been implicated as a CKD risk factor. However there is limited evidence that treatment of periodontal disease slows the progression of CKD. We describe the protocol of the Kidney and Periodontal Disease (KAPD) study, a 12-month un-blinded, randomized, controlled pilot trial with two intent-to-treat treatment arms: 1. immediate intensive non-surgical periodontal treatment or 2. rescue treatment with delayed intensive treatment. The goals of this pilot study are to test the feasibility of conducting a larger trial in an ethnically and racially diverse, underserved population (mostly poor and/or low literacy) with both CKD and significant periodontal disease to determine the effect of intensive periodontal treatment on renal and inflammatory biomarkers over a 12-month period. To date, KAPD has identified 634 potentially eligible patients who were invited to in-person screening. Of the 83 (13.1%) of potentially eligible patients who attended in-person screening, 51 (61.4%) were eligible for participation and 46 enrolled in the study. The mean age of participants is 59.2years (range 34 to 73). Twenty of the participants (43.5%) are Black and 22 (47.8%) are Hispanic. Results from the KAPD study will provide needed preliminary evidence of the effectiveness of non-surgical periodontal treatment to slow CKD progression and inform the design future clinical research trials. Copyright © 2016. Published by Elsevier Inc.

High-sensitivity detection of breast tumors in vivo by use of a pH-sensitive near-infrared fluorescence probe

NASA Astrophysics Data System (ADS)

Mathejczyk, Julia Eva; Pauli, Jutta; Dullin, Christian; Resch-Genger, Ute; Alves, Frauke; Napp, Joanna

2012-07-01

We investigated the potential of the pH-sensitive dye, CypHer5E, conjugated to Herceptin (pH-Her) for the sensitive detection of breast tumors in mice using noninvasive time-domain near-infrared fluorescence imaging and different methods of data analysis. First, the fluorescence properties of pH-Her were analyzed as function of pH and/or dye-to-protein ratio, and binding specificity was confirmed in cell-based assays. Subsequently, the performance of pH-Her in nude mice bearing orthotopic HER2-positive (KPL-4) and HER2-negative (MDA-MB-231) breast carcinoma xenografts was compared to that of an always-on fluorescent conjugate Alexa Fluor 647-Herceptin (Alexa-Her). Subtraction of autofluorescence and lifetime (LT)-gated image analyses were performed for background fluorescence suppression. In mice bearing HER2-positive tumors, autofluorescence subtraction together with the selective fluorescence enhancement of pH-Her solely in the tumor's acidic environment provided high contrast-to-noise ratios (CNRs). This led to an improved sensitivity of tumor detection compared to Alexa-Her. In contrast, LT-gated imaging using LTs determined in model systems did not improve tumor-detection sensitivity in vivo for either probe. In conclusion, pH-Her is suitable for sensitive in vivo monitoring of HER2-expressing breast tumors with imaging in the intensity domain and represents a promising tool for detection of weak fluorescent signals deriving from small tumors or metastases.

Spectral analysis of fundus autofluorescence pattern as a tool to detect early stages of degeneration in the retina and retinal pigment epithelium.

PubMed

Feldman, Tatiana B; Yakovleva, Marina A; Larichev, Andrey V; Arbukhanova, Patimat M; Radchenko, Alexandra Sh; Borzenok, Sergey A; Kuzmin, Vladimir A; Ostrovsky, Mikhail A

2018-05-22

The aim of this work is the determination of quantitative diagnostic criteria based on the spectral characteristics of fundus autofluorescence to detect early stages of degeneration in the retina and retinal pigment epithelium (RPE). RPE cell suspension samples were obtained from the cadaver eyes with and without signs of age-related macular degeneration (AMD). Fluorescence analysis at an excitation wavelength of 488 nm was performed. The fluorescence lifetimes of lipofuscin-granule fluorophores were measured by counting time-correlated photon method. Comparative analysis of fluorescence spectra of RPE cell suspensions from the cadaver eyes with and without signs of AMD showed a significant difference in fluorescence intensity at 530-580 nm in response to fluorescence excitation at 488 nm. It was notably higher in eyes with visual pathology than in normal eyes regardless of the age of the eye donor. Measurements of fluorescence lifetimes of lipofuscin fluorophores showed that the contribution of photooxidation and photodegradation products of bisretinoids to the total fluorescence at 530-580 nm of RPE cell suspensions was greater in eyes with visual pathology than in normal eyes. Because photooxidation and photodegradation products of bisretinoids are markers of photodestructive processes, which can cause RPE cell death and initiate degenerative processes in the retina, quantitative determination of increases in these bisretinoid products in lipofuscin granules may be used to establish quantitative diagnostic criteria for degenerative processes in the retina and RPE.

Fluctuation localization imaging-based fluorescence in situ hybridization (fliFISH) for accurate detection and counting of RNA copies in single cells

DOE PAGES

Cui, Yi; Hu, Dehong; Markillie, Lye Meng; ...

2017-10-04

Here, quantitative gene expression analysis in intact single cells can be achieved using single molecule-based fluorescence in situ hybridization (smFISH). This approach relies on fluorescence intensity to distinguish between true signals, emitted from an RNA copy hybridized with multiple oligonucleotide probes, and background noise. Thus, the precision in smFISH is often compromised by partial or nonspecific probe binding and tissue autofluorescence, especially when only a small number of probes can be fitted to the target transcript. Here we provide an accurate approach for setting quantitative thresholds between true and false signals, which relies on on-off duty cycles of photoswitchable dyes.more » This fluctuation localization imaging-based FISH (fliFISH) uses on-time fractions (measured over a series of exposures) collected from transcripts bound to as low as 8 probes, which are distinct from on-time fractions collected from nonspecifically bound probes or autofluorescence. Using multicolor fliFISH, we identified radial gene expression patterns in mouse pancreatic islets for insulin, the transcription factor, NKX2-2 and their ratio ( Nkx2- 2/Ins2). These radial patterns, showing higher values in β cells at the islet core and lower values in peripheral cells, were lost in diabetic mouse islets. In summary, fliFISH provides an accurate, quantitative approach for detecting and counting true RNA copies and rejecting false signals by their distinct on-time fractions, laying the foundation for reliable single-cell transcriptomics.« less

Fluctuation localization imaging-based fluorescence in situ hybridization (fliFISH) for accurate detection and counting of RNA copies in single cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, Yi; Hu, Dehong; Markillie, Lye Meng

Here, quantitative gene expression analysis in intact single cells can be achieved using single molecule-based fluorescence in situ hybridization (smFISH). This approach relies on fluorescence intensity to distinguish between true signals, emitted from an RNA copy hybridized with multiple oligonucleotide probes, and background noise. Thus, the precision in smFISH is often compromised by partial or nonspecific probe binding and tissue autofluorescence, especially when only a small number of probes can be fitted to the target transcript. Here we provide an accurate approach for setting quantitative thresholds between true and false signals, which relies on on-off duty cycles of photoswitchable dyes.more » This fluctuation localization imaging-based FISH (fliFISH) uses on-time fractions (measured over a series of exposures) collected from transcripts bound to as low as 8 probes, which are distinct from on-time fractions collected from nonspecifically bound probes or autofluorescence. Using multicolor fliFISH, we identified radial gene expression patterns in mouse pancreatic islets for insulin, the transcription factor, NKX2-2 and their ratio ( Nkx2- 2/Ins2). These radial patterns, showing higher values in β cells at the islet core and lower values in peripheral cells, were lost in diabetic mouse islets. In summary, fliFISH provides an accurate, quantitative approach for detecting and counting true RNA copies and rejecting false signals by their distinct on-time fractions, laying the foundation for reliable single-cell transcriptomics.« less

Combined SERS biotags (SBTs) and microfluidic platform for the quantitative ratiometric discrimination between noncancerous and cancerous cells in flow

NASA Astrophysics Data System (ADS)

Pallaoro, Alessia; Hoonejani, Mehran R.; Braun, Gary B.; Meinhart, Carl; Moskovits, Martin

2012-10-01

SERS biotags are made from polymer-encapsulated silver nanoparticle dimers infused with unique Raman reporter molecules, and carry peptides as cell recognition moieties. We demonstrate their potential use for early and rapid identification of malignant cells, a central goal in cancer research. SERS biotags (SBTs) can be routinely synthesized and simultaneously excited with a single, low intensity laser source, making the determination of the relative contribution of the individual SBTs to the overall spectrum tractable. Importantly for biomedical applications, SERS employs tissuepenetrating lasers in the red to near-infrared range resulting in low autofluorescence. We have previously described a multiplexed, ratiometric method that can confidently distinguish between cancerous and noncancerous epithelial prostate cells in vitro based on receptor overexpression. Here we present the progress towards the application of this quantitative methodology for the identification of cancer cells in a microfluidic flow-focusing device. Beads are used as cell mimics to characterize the devices. Cells (and beads) are simultaneously incubated with two sets of SBTs while in suspension (simulating cells' capture from blood), then injected into the device for laser interrogation under flow. Each cell event is characterized by a composite Raman spectrum, deconvoluted into its single components to ultimately determine their relative contribution. We show that using SBTs ratiometrically can provide cell identification insensitive to normal causes of uncertainty in optical measurements such as variations in focal plane, cell concentration, autofluorescence, and turbidity.

Time-gated luminescence microscopy allowing direct visual inspection of lanthanide-stained microorganisms in background-free condition.

PubMed

Jin, Dayong; Piper, James A

2011-03-15

Application of standard immuno-fluorescence microscopy techniques for detection of rare-event microorganisms in dirty samples is severely limited by autofluorescence of nontarget organisms or other debris. Time-gated detection using gateable array detectors in combination with microsecond-lifetime luminescent bioprobes (usually lanthanide-based) is highly effective in suppression of (nanosecond-lifetime) autofluorescence background; however, the complexity and cost of the instrumentation is a major barrier to application of these techniques to routine diagnostics. We report a practical, low-cost implementation of time-gated luminescence detection in a standard epifluorescence microscope which has been modified to include a high-power pulsed UV light-emitting diode (LED) illumination source and a standard fast chopper inserted in the focal plane behind a microscope eyepiece. Synchronization of the pulsed illumination/gated detection cycle is driven from the clock signal from the chopper. To achieve time-gated luminescence intensities sufficient for direct visual observation, we use high cycle rates, up to 2.5 kHz, taking advantage of the fast switching capabilities of the LED source. We have demonstrated real-time direct-visual inspection of europium-labeled Giardia lamblia cysts in dirty samples and Cryptosporidium parvum oocysts in fruit juice concentrate. The signal-to-background ratio has been enhanced by a factor of 18 in time-gated mode. The availability of low-cost, robust time-gated microscopes will aid development of long-lifetime luminescence bioprobes and accelerate their application in routine laboratory diagnostics.

Image-enhanced endoscopy for diagnosis of colorectal tumors in view of endoscopic treatment

PubMed Central

Yoshida, Naohisa; Yagi, Nobuaki; Yanagisawa, Akio; Naito, Yuji

2012-01-01

Recently, image-enhanced endoscopy (IEE) has been used to diagnose gastrointestinal tumors. This method is a change from conventional white-light (WL) endoscopy without dyeing solution, requiring only the push of a button. In IEE, there are many advantages in diagnosis of neoplastic tumors, evaluation of invasion depth for cancerous lesions, and detection of neoplastic lesions. In narrow band imaging (NBI) systems (Olympus Medical Co., Tokyo, Japan), optical filters that allow narrow-band light to pass at wavelengths of 415 and 540 nm are used. Mucosal surface blood vessels are seen most clearly at 415 nm, which is the wavelength that corresponds to the hemoglobin absorption band, while vessels in the deep layer of the mucosa can be detected at 540 nm. Thus, NBI also can detect pit-like structures named surface pattern. The flexible spectral imaging color enhancement (FICE) system (Fujifilm Medical Co., Tokyo, Japan) is also an IEE but different to NBI. FICE depends on the use of spectral-estimation technology to reconstruct images at different wavelengths based on WL images. FICE can enhance vascular and surface patterns. The autofluorescence imaging (AFI) video endoscope system (Olympus Medical Co., Tokyo, Japan) is a new illumination method that uses the difference in intensity of autofluorescence between the normal area and neoplastic lesions. AFI light comprises a blue light for emitting and a green light for hemoglobin absorption. The aim of this review is to highlight the efficacy of IEE for diagnosis of colorectal tumors for endoscopic treatment. PMID:23293724

Differentiation of tissue and kidney stones for laser lithotripsy using different spectroscopic approaches

NASA Astrophysics Data System (ADS)

Lange, Birgit; Cordes, Jens; Brinkmann, Ralf

2015-07-01

Holmium lasers are nowadays the gold standard for endoscopic laser lithotripsy. However, there is a risk of damaging or perforating the ureter or kidney tissue when the vision is poor. An automatic tissue/stone differentiation would improve the handling and safety of the procedure. To achieve this objective, an easy and robust real-time discrimination method has to be found which can be used to realize a feedback loop to control the laser system. Two possible approaches have been evaluated: White light reflectance and fluorescence spectroscopy. In both cases, we use the treatment fiber for detection and evaluate the possibility to decide whether the fiber is placed in front of tissue or calculus by the signal that is delivered by the surface in front of it. White light reflectance spectroscopy uses the standard light source for endourologic surgeries: Radiation of a Xenon light source is coupled to the ureteroscope via a liquid light guide. The part of the white light that is reflected back into the fiber is spectroscopically analyzed. In a clinical proof of concept study reflection signals were measured in vivo in 8 patients. For differentiation of stone and tissue via autofluorescence, excitation as well as detection was done via the treatment fiber. A suitable excitation wavelength was chosen with in vitro measurements (UV / visible) on several human renal calculi and porcine tissues. For verification of the positive results with green excitation in a clinical proof of concept study, a measurement set-up was realized which allows the recording of fluorescence signals during an endourological intervention.

Association of Intensive Blood Pressure Control and Kidney Disease Progression in Nondiabetic Patients With Chronic Kidney Disease: A Systematic Review and Meta-analysis.

PubMed

Tsai, Wan-Chuan; Wu, Hon-Yen; Peng, Yu-Sen; Yang, Ju-Yeh; Chen, Hung-Yuan; Chiu, Yen-Ling; Hsu, Shih-Ping; Ko, Mei-Ju; Pai, Mei-Fen; Tu, Yu-Kang; Hung, Kuan-Yu; Chien, Kuo-Liong

2017-06-01

The optimal blood pressure (BP) target remains debated in nondiabetic patients with chronic kidney disease (CKD). To compare intensive BP control (<130/80 mm Hg) with standard BP control (<140/90 mm Hg) on major renal outcomes in patients with CKD without diabetes. Searches of PubMed, MEDLINE, Embase, and Cochrane Library for publications up to March 24, 2016. Randomized clinical trials that compared an intensive vs a standard BP target in nondiabetic adults with CKD, reporting changes in glomerular filtration rate (GFR), doubling of serum creatinine level, 50% reduction in GFR, end-stage renal disease (ESRD), or all-cause mortality. Random-effects meta-analyses for pooling effect measures. Meta-regression and subgroup analyses for exploring heterogeneity. Differences in annual rate of change in GFR were expressed as mean differences with 95% CIs. Differences in doubling of serum creatinine or 50% reduction in GFR, ESRD, composite renal outcome, and all-cause mortality were expressed as risk ratios (RRs) with 95% CIs. We identified 9 trials with 8127 patients and a median follow-up of 3.3 years. Compared with standard BP control, intensive BP control did not show a significant difference on the annual rate of change in GFR (mean difference, 0.07; 95% CI, -0.16 to 0.29 mL/min/1.73 m2/y), doubling of serum creatinine level or 50% reduction in GFR (RR, 0.99; 95% CI, 0.76-1.29), ESRD (RR, 0.96; 95% CI, 0.78-1.18), composite renal outcome (RR, 0.99; 95% CI, 0.81-1.21), or all-cause mortality (RR, 0.95; 95% CI, 0.66-1.37). Nonblacks and patients with higher levels of proteinuria showed a trend of lower risk of kidney disease progression with intensive BP control. Targeting BP below the current standard did not provide additional benefit for renal outcomes compared with standard treatment during a follow-up of 3.3 years in patients with CKD without diabetes. However, nonblack patients or those with higher levels of proteinuria might benefit from the intensive BP-lowering treatments.

Quantitative light-induced fluorescence technology for quantitative evaluation of tooth wear

NASA Astrophysics Data System (ADS)

Kim, Sang-Kyeom; Lee, Hyung-Suk; Park, Seok-Woo; Lee, Eun-Song; de Josselin de Jong, Elbert; Jung, Hoi-In; Kim, Baek-Il

2017-12-01

Various technologies used to objectively determine enamel thickness or dentin exposure have been suggested. However, most methods have clinical limitations. This study was conducted to confirm the potential of quantitative light-induced fluorescence (QLF) using autofluorescence intensity of occlusal surfaces of worn teeth according to enamel grinding depth in vitro. Sixteen permanent premolars were used. Each tooth was gradationally ground down at the occlusal surface in the apical direction. QLF-digital and swept-source optical coherence tomography images were acquired at each grinding depth (in steps of 100 μm). All QLF images were converted to 8-bit grayscale images to calculate the fluorescence intensity. The maximum brightness (MB) values of the same sound regions in grayscale images before (MB) and phased values after (MB) the grinding process were calculated. Finally, 13 samples were evaluated. MB increased over the grinding depth range with a strong correlation (r=0.994, P<0.001). In conclusion, the fluorescence intensity of the teeth and grinding depth was strongly correlated in the QLF images. Therefore, QLF technology may be a useful noninvasive tool used to monitor the progression of tooth wear and to conveniently estimate enamel thickness.

Fluorescent biopsy of biological tissues in differentiation of benign and malignant tumors of prostate

NASA Astrophysics Data System (ADS)

Trifoniuk, L. I.; Ushenko, Yu. A.; Sidor, M. I.; Minzer, O. P.; Gritsyuk, M. V.; Novakovskaya, O. Y.

2014-08-01

The work consists of investigation results of diagnostic efficiency of a new azimuthally stable Mueller-matrix method of analysis of laser autofluorescence coordinate distributions of biological tissues histological sections. A new model of generalized optical anisotropy of biological tissues protein networks is proposed in order to define the processes of laser autofluorescence. The influence of complex mechanisms of both phase anisotropy (linear birefringence and optical activity) and linear (circular) dichroism is taken into account. The interconnections between the azimuthally stable Mueller-matrix elements characterizing laser autofluorescence and different mechanisms of optical anisotropy are determined. The statistic analysis of coordinate distributions of such Mueller-matrix rotation invariants is proposed. Thereupon the quantitative criteria (statistic moments of the 1st to the 4th order) of differentiation of histological sections of uterus wall tumor - group 1 (dysplasia) and group 2 (adenocarcinoma) are estimated.

System of polarization correlometry of polycrystalline layers of urine in the differentiation stage of diabetes

NASA Astrophysics Data System (ADS)

Ushenko, Yu. O.; Pashkovskaya, N. V.; Marchuk, Y. F.; Dubolazov, O. V.; Savich, V. O.

2015-08-01

The work consists of investigation results of diagnostic efficiency of a new azimuthally stable Muellermatrix method of analysis of laser autofluorescence coordinate distributions of biological liquid layers. A new model of generalized optical anisotropy of biological tissues protein networks is proposed in order to define the processes of laser autofluorescence. The influence of complex mechanisms of both phase anisotropy (linear birefringence and optical activity) and linear (circular) dichroism is taken into account. The interconnections between the azimuthally stable Mueller-matrix elements characterizing laser autofluorescence and different mechanisms of optical anisotropy are determined. The statistic analysis of coordinate distributions of such Mueller-matrix rotation invariants is proposed. Thereupon the quantitative criteria (statistic moments of the 1st to the 4th order) of differentiation of human urine polycrystalline layers for the sake of diagnosing and differentiating cholelithiasis with underlying chronic cholecystitis (group 1) and diabetes mellitus of degree II (group 2) are estimated.

Methods and means of Fourier-Stokes polarimetry and the spatial-frequency filtering of phase anisotropy manifestations in endometriosis diagnostics

NASA Astrophysics Data System (ADS)

Ushenko, A. G.; Dubolazov, O. V.; Ushenko, Vladimir A.; Ushenko, Yu. A.; Sakhnovskiy, M. Yu.; Prydiy, O. G.; Lakusta, I. I.; Novakovskaya, O. Yu.; Melenko, S. R.

2016-12-01

This research presents investigation results of diagnostic efficiency of a new azimuthally stable Mueller-matrix method of laser autofluorescence coordinate distributions analysis of dried polycrystalline films of uterine cavity peritoneal fluid. A new model of generalized optical anisotropy of biological tissues protein networks is proposed in order to define the processes of laser autofluorescence. The influence of complex mechanisms of both phase anisotropy (linear birefringence and optical activity) and linear (circular) dichroism is taken into account. The interconnections between the azimuthally stable Mueller-matrix elements characterizing laser autofluorescence and different mechanisms of optical anisotropy are determined. The statistic analysis of coordinate distributions of such Mueller-matrix rotation invariants is proposed. Thereupon the quantitative criteria (statistic moments of the 1st to the 4th order) of differentiation of dried polycrystalline films of peritoneal fluid - group 1 (healthy donors) and group 2 (uterus endometriosis patients) are estimated.

A Score for Predicting Acute Kidney Injury After Coronary Artery Bypass Graft Surgery in an Asian Population.

PubMed

Mithiran, Harish; Kunnath Bonney, Glenn; Bose, Saideep; Subramanian, Srinivas; Zhe Yan, Zan Ng; Zong En, Seth Yeak; Papadimas, Evangelos; Chauhan, Ishaan; MacLaren, Graeme; Kofidis, Theodoros

2016-10-01

To develop a scoring system to predict acute kidney injury in Asian patients after coronary artery bypass grafting. A retrospective analysis of data collected in an institutional cardiac database. A tertiary academic hospital in a large metropolitan city. The study comprised 954 patients with coronary artery disease. All patients underwent coronary artery bypass surgery with cardiopulmonary bypass but did not undergo any other concomitant procedures. The main outcome measured was acute kidney injury as defined by the Acute Kidney Injury Network criteria. The following 6 clinical variables were independent predictors of kidney injury: age>60 years, diabetes requiring insulin, estimated glomerular filtration rate<60 mL/min/1.73 m(2), ejection fraction<40%, cardiopulmonary bypass time>140 minutes, and aortic cross-clamp time>100 minutes. These variables were used to develop the Singapore Acute Kidney Injury score. The Singapore Acute Kidney Injury score is a simple way to predict, at the time of admission to the intensive care unit, an Asian patient's risk of developing acute kidney injury after coronary artery bypass surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

Significance of Technetium-99m Human Serum Albumin Diethylenetriamine Pentaacetic Acid Scintigraphy in Patients with Nephrotic Syndrome

PubMed Central

Takashima, Tsuyoshi; Kishi, Tomoya; Onozawa, Koji; Rikitake, Shuichi; Miyazono, Motoaki; Otsuka, Takateru; Irie, Hiroyuki; Iwakiri, Ryuichi; Fujimoto, Kazuma; Ikeda, Yuji

2015-01-01

It is thought that a large amount of albumin leaking from the glomerulus in nephrotic syndrome (NS) is reabsorbed at the proximal tubule and catabolized. Therefore, it is possible the final quantity of urinary protein does not always reflect the amount of leakage of protein from the glomerulus. We experienced two cases without nephrotic range proteinuria thought to involve hypoproteinemia due to the same pathophysiology as NS. On these patients, we performed protein leakage scintigraphy with technetium-99m human serum albumin diethylenetriamine pentaacetic acid (99mTc-HSAD) to exclude a diagnosis of protein-losing gastroenteropathy and observed diffuse positive accumulation in the kidneys with more intense uptake in the kidney than the liver on the anterior view 24 hours after 99mTc-HSAD administration. In healthy adults intravenously given 99mTc-HSAD, the same dynamics are observed as in albumin metabolism, and the organ radioactivity of the liver and kidneys after 24 hours is equal. Therefore, we thought it was possible that the renal uptake 24 hours after 99mTc-HSAD administration was a characteristic finding of NS. In order to confirm it, the subjects were divided into two groups: the NS group (n = 10) and the non-NS group (n = 7). We defined more intense uptake in the kidney than the liver on the anterior view 24 hours after 99mTc-HSAD administration as Dense Kidney (+). Furthermore, we designed regions of interest in the right and left kidneys and liver on anterior and posterior images, then calculated the kidney-liver ratio. Nine of the ten patients had Dense Kidney (+) in the NS group, compared to none in the non-NS group. And the kidney-liver ratio was significantly higher in the NS group than in the non-NS group on each view in the bilateral kidneys. In conclusion, our results suggest that the renal uptake 24 hours after 99mTc-HSAD administration is a characteristic finding of NS. PMID:25859658

[Long-term outcomes of children treated with continuous renal replacement therapy].

PubMed

Almarza, S; Bialobrzeska, K; Casellas, M M; Santiago, M J; López-Herce, J; Toledo, B; Carrillo, Á

2015-12-01

The objective of this study is to analyze long-term outcomes and kidney function in children requiring continuous renal replacement therapy (CRRT) after an acute kidney injury episode. A retrospective observational study was performed using a prospective database of 128 patients who required CRRT admitted to the pediatric intensive care unit between years 2006 and 2012. The subsequent outcomes were assessed in those surviving at hospital discharge. Of the 128 children who required RRT in the pediatric intensive care unit, 71 survived at hospital discharge (54.4%), of whom 66 (92.9%) were followed up. Three patients had chronic renal failure prior to admission to the NICU. Of the 63 remaining patients, 6 had prolonged or relapses of renal function disturbances, but only one patient with atypical Hemolytic Uremic Syndrome developed end-stage renal failure. The rest had normal kidney function at the last check-up. Most of surviving children that required CRRT have a positive outcome later on, presenting low mortality rates and recovery of kidney function in the medium term. Copyright © 2014 Asociación Española de Pediatría. Published by Elsevier España, S.L.U. All rights reserved.

Consistency of signal intensity and T2* in frozen ex vivo heart muscle, kidney, and liver tissue.

PubMed

Kaye, Elena A; Josan, Sonal; Lu, Aiming; Rosenberg, Jarrett; Daniel, Bruce L; Pauly, Kim Butts

2010-03-01

To investigate tissue dependence of the MRI-based thermometry in frozen tissue by quantification and comparison of signal intensity and T2* of ex vivo frozen tissue of three different types: heart muscle, kidney, and liver. Tissue samples were frozen and imaged on a 0.5 Tesla MRI scanner with ultrashort echo time (UTE) sequence. Signal intensity and T2* were determined as the temperature of the tissue samples was decreased from room temperature to approximately -40 degrees C. Statistical analysis was performed for (-20 degrees C, -5 degrees C) temperature interval. The findings of this study demonstrate that signal intensity and T2* are consistent across three types of tissue for (-20 degrees C, -5 degrees C) temperature interval. Both parameters can be used to calculate a single temperature calibration curve for all three types of tissue and potentially in the future serve as a foundation for tissue-independent MRI-based thermometry.

Gut-kidney crosstalk in septic acute kidney injury.

PubMed

Zhang, Jingxiao; Ankawi, Ghada; Sun, Jian; Digvijay, Kumar; Yin, Yongjie; Rosner, Mitchell H; Ronco, Claudio

2018-05-03

Sepsis is the leading cause of acute kidney injury (AKI) in the intensive care unit (ICU). Septic AKI is a complex and multifactorial process that is incompletely understood. During sepsis, the disruption of the mucus membrane barrier, a shift in intestinal microbial flora, and microbial translocation may lead to systemic inflammation, which further alters host immune and metabolic homeostasis. This altered homeostasis may promote and potentiate the development of AKI. As part of this vicious cycle, when AKI develops, the clearance of inflammatory mediators and metabolic products is decreased. This will lead to further gut injury and breakdown in mucous membrane barriers. Thus, changes in the gut during sepsis can initiate and propagate septic AKI. This deleterious gut-kidney crosstalk may be a potential target for therapeutic maneuvers. This review analyses the underlying mechanisms in gut-kidney crosstalk in septic AKI.

Testing of candidate non-lethal sampling methods for detection of Renibacterium salmoninarum in juvenile Chinook salmon Oncorhynchus tshawytscha

USGS Publications Warehouse

Elliott, Diane G.; McKibben, Constance L.; Conway, Carla M.; Purcell, Maureen K.; Chase, Dorothy M.; Applegate, Lynn M.

2015-01-01

Non-lethal pathogen testing can be a useful tool for fish disease research and management. Our research objectives were to determine if (1) fin clips, gill snips, surface mucus scrapings, blood draws, or kidney biopsies could be obtained non-lethally from 3 to 15 g Chinook salmon Oncorhynchus tshawytscha, (2) non-lethal samples could accurately discriminate between fish exposed to the bacterial kidney disease agent Renibacterium salmoninarum and non-exposed fish, and (3) non-lethal samples could serve as proxies for lethal kidney samples to assess infection intensity. Blood draws and kidney biopsies caused ≥5% post-sampling mortality (Objective 1) and may be appropriate only for larger fish, but the other sample types were non-lethal. Sampling was performed over 21 wk following R. salmoninarum immersion challenge of fish from 2 stocks (Objectives 2 and 3), and nested PCR (nPCR) and real-time quantitative PCR (qPCR) results from candidate non-lethal samples were compared with kidney tissue analysis by nPCR, qPCR, bacteriological culture, enzyme-linked immunosorbent assay (ELISA), fluorescent antibody test (FAT) and histopathology/immunohistochemistry. R. salmoninarum was detected by PCR in >50% of fin, gill, and mucus samples from challenged fish. Mucus qPCR was the only non-lethal assay exhibiting both diagnostic sensitivity and specificity estimates >90% for distinguishing between R. salmoninarum-exposed and non-exposed fish and was the best candidate for use as an alternative to lethal kidney sample testing. Mucus qPCR R. salmoninarum quantity estimates reflected changes in kidney bacterial load estimates, as evidenced by significant positive correlations with kidney R. salmoninaruminfection intensity scores at all sample times and in both fish stocks, and were not significantly impacted by environmentalR. salmoninarum concentrations.

Fully automatic region of interest selection in glomerular filtration rate estimation from 99mTc-DTPA renogram.

PubMed

Lin, Kun-Ju; Huang, Jia-Yann; Chen, Yung-Sheng

2011-12-01

Glomerular filtration rate (GFR) is a common accepted standard estimation of renal function. Gamma camera-based methods for estimating renal uptake of (99m)Tc-diethylenetriaminepentaacetic acid (DTPA) without blood or urine sampling have been widely used. Of these, the method introduced by Gates has been the most common method. Currently, most of gamma cameras are equipped with a commercial program for GFR determination, a semi-quantitative analysis by manually drawing region of interest (ROI) over each kidney. Then, the GFR value can be computed from the scintigraphic determination of (99m)Tc-DTPA uptake within the kidney automatically. Delineating the kidney area is difficult when applying a fixed threshold value. Moreover, hand-drawn ROIs are tedious, time consuming, and dependent highly on operator skill. Thus, we developed a fully automatic renal ROI estimation system based on the temporal changes in intensity counts, intensity-pair distribution image contrast enhancement method, adaptive thresholding, and morphological operations that can locate the kidney area and obtain the GFR value from a (99m)Tc-DTPA renogram. To evaluate the performance of the proposed approach, 30 clinical dynamic renograms were introduced. The fully automatic approach failed in one patient with very poor renal function. Four patients had a unilateral kidney, and the others had bilateral kidneys. The automatic contours from the remaining 54 kidneys were compared with the contours of manual drawing. The 54 kidneys were included for area error and boundary error analyses. There was high correlation between two physicians' manual contours and the contours obtained by our approach. For area error analysis, the mean true positive area overlap is 91%, the mean false negative is 13.4%, and the mean false positive is 9.3%. The boundary error is 1.6 pixels. The GFR calculated using this automatic computer-aided approach is reproducible and may be applied to help nuclear medicine physicians in clinical practice.

STRUCTURAL ASSESSMENT OF HYPERAUTOFLUORESCENT RING IN PATIENTS WITH RETINITIS PIGMENTOSA

PubMed Central

LIMA, LUIZ H.; CELLA, WENER; GREENSTEIN, VIVIENNE C.; WANG, NAN-KAI; BUSUIOC, MIHAI; THEODORE SMITH, R.; YANNUZZI, LAWRENCE A.; TSANG, STEPHEN H.

2009-01-01

Purpose To analyze the retinal structure underlying the hyperautofluorescent ring visible on fundus autofluorescence in patients with retinitis pigmentosa. Methods Twenty-four eyes of 13 patients with retinitis pigmentosa, aged 13 years to 67 years, were studied. The integrity of the photoreceptor cilia, also known as the inner/outer segment junction of the photoreceptors, the outer nuclear layer, and retinal pigment epithelium, was evaluated outside, across, and inside the ring with spectral-domain optical coherence tomography (OCT). Results Inside the foveal area, fundus autofluorescence did not detect abnormalities. Outside the ring, fundus autofluorescence revealed hypoautofluorescence compatible with the photoreceptor/retinal pigment epithelium degeneration. Spectral-domain OCT inside the ring, in the area of normal foveal fundus autofluorescence, revealed an intact retinal structure in all eyes and total retinal thickness values that were within normal limits. Across the ring, inner/outer segment junction disruption was observed and the outer nuclear layer was decreased in thickness in a centrifugal direction in all eyes. Outside the hyperautofluorescent ring, the inner/outer segment junction and the outer nuclear layer appeared to be absent and there were signs of retinal pigment epithelium degeneration. Conclusion Disruption of the inner/outer segment junction and a decrease in outer retinal thickness were found across the central hyperautofluorescent ring seen in retinitis pigmentosa. Outer segment phagocytosis by retinal pigment epithelium is necessary for the formation of an hyperautofluorescent ring. PMID:19584660

Fundus autofluorescence patterns in primary intraocular lymphoma.

PubMed

Casady, Megan; Faia, Lisa; Nazemzadeh, Maryam; Nussenblatt, Robert; Chan, Chi-Chao; Sen, H Nida

2014-02-01

To evaluate fundus autofluorescence (FAF) patterns in patients with primary intraocular (vitreoretinal) lymphoma. Records of all patients with primary intraocular lymphoma who underwent FAF imaging at the National Eye Institute were reviewed. Fundus autofluorescence patterns were evaluated with respect to clinical disease status and the findings on fluorescein angiography and spectral-domain optical coherence tomography. There were 18 eyes (10 patients) with primary intraocular lymphoma that underwent FAF imaging. Abnormal autofluorescence in the form of granular hyperautofluorescence and hypoautofluorescence was seen in 11 eyes (61%), and blockage by mass lesion was seen in 2 eyes (11%). All eyes with granular pattern on FAF had active primary intraocular lymphoma at the time of imaging, but there were 5 eyes with unremarkable FAF, which were found to have active lymphoma. The most common pattern on fluorescein angiography was hypofluorescent round spots with a "leopard spot" appearance (43%). These hypofluorescent spots on fluorescein angiography correlated with hyperautofluorescent spots on FAF in 5 eyes (36%) (inversion of FAF). Nodular hyperreflective spots at the level of retinal pigment epithelium on optical coherence tomography were noted in 43% of eyes. The hyperautofluorescent spots on FAF correlated with nodular hyperreflective spots on optical coherence tomography in 6 eyes (43%). Granularity on FAF was associated with active lymphoma in majority of the cases. An inversion of FAF (hyperautofluorescent spots on FAF corresponding to hypofluorescent spots on fluorescein angiography) was observed in less than half of the eyes.

FUNDUS AUTOFLUORESCENCE IN RUBELLA RETINOPATHY: Correlation With Photoreceptor Structure and Function.

PubMed

Bukowska, Danuta M; Wan, Sue Ling; Chew, Avenell L; Chelva, Enid; Tang, Ivy; Mackey, David A; Chen, Fred K

2017-01-01

To illustrate altered fundus autofluorescence in rubella retinopathy and to investigate their relationships with photoreceptor structure and function using multimodal imaging. The authors report four cases of rubella retinopathy aged 8, 33, 42, and 50 years. All patients had dilated clinical fundus examination; wide-field color photography; blue, green, and near-infrared autofluorescence imaging and spectral domain optical coherence tomography. Two patients also underwent microperimetry and adaptive optics imaging. En face optical coherence tomography, cone mosaic, and microperimetry were coregistered with autofluorescence images. The authors explored the structure-function correlation. All four patients had a "salt-and-pepper" appearance on dilated fundus examination and wide-field color photography. There were variable-sized patches of hypoautofluorescence on both blue and near-infrared excitation in all four patients. Wave-guiding cones were visible and retinal sensitivity was intact over these regions. There was no correlation between hypoautofluorescence and regions of attenuated ellipsoid and interdigitation zones. Hyperautofluorescent lesions were also noted and some of these were pseudo-vitelliform lesions. Patchy hypoautofluorescence on near-infrared excitation can be a feature of rubella retinopathy. This may be due to abnormal melanin production or loss of melanin within retinal pigment epithelium cells harboring persistent rubella virus infection. Preservation of the ellipsoid zone, wave-guiding cones, and retinal sensitivity within hypoautofluorescent lesions suggest that these retinal pigment epithelium changes have only mild impact on photoreceptor cell function.

Retinal pigment epithelial changes in chronic Vogt-Koyanagi-Harada disease: fundus autofluorescence and spectral domain optical coherence tomography findings

PubMed Central

Vasconcelos-Santos, Daniel V.; Sohn, Elliott H.; Sadda, Srinivas; Rao, Narsing A.

2009-01-01

Purpose To determine whether fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (SD-OCT) imaging allows better assessment of RPE and outer retina (OR) in subjects with chronic VKH compared to examination and angiography alone. Methods Cross-sectional analysis of a series of seven consecutive patients with chronic VKH undergoing FAF and SD-OCT. Chronic VKH was defined as during >3 months. Color fundus photographs were correlated to FAF and SD-OCT images. The images were later correlated to fluorescein angiography (FA) and indocyanine green angiography (ICG-A). Results All patients had sunset glow fundus, which resulted in no apparent corresponding abnormality on FAF or SD-OCT. Lesions with decreased autofluorescence signal were observed in 11 eyes (85%), being associated with loss of the RPE and involvement of OR on SD-OCT. In 5 eyes (38%) some of these lesions were very subtle on clinical examination but easily detected by FAF. Lesions with increased autofluorescence signal were seen in 8 eyes (61.5%), showing variable involvement of the OR on SD-OCT and corresponding clinically to areas of RPE proliferation and cystoid macular edema. Conclusion Combined use of FAF and SD-OCT imaging allowed noninvasive delineation of RPE/OR changes in patients with chronic VKH, which were consistent with previous histopathological reports. Some of these changes were not apparent on clinical examination. PMID:20010321

Two-photon excited fluorescence microscopy application for ex vivo investigation of ocular fundus samples

NASA Astrophysics Data System (ADS)

Peters, Sven; Hammer, Martin; Schweitzer, Dietrich

2011-07-01

Two-photon excited fluorescence (TPEF) imaging of ocular tissue has recently become a promising tool in ophthalmology for diagnostic and research purposes. The feasibility and the advantages of TPEF imaging, namely deeper tissue penetration and improved high-resolution imaging of microstructures, have been demonstrated lately using human ocular samples. The autofluorescence properties of endogenous fluorophores in ocular fundus tissue are well known from spectrophotometric analysis. But fluorophores, especially when it comes to fluorescence lifetime, typically display a dependence of their fluorescence properties on local environmental parameters. Hence, a more detailed investigation of ocular fundus autofluorescence ideally in vivo is of utmost interest. The aim of this study is to determine space-resolved the stationary and time-resolved fluorescence properties of endogenous fluorophores in ex vivo porcine ocular fundus samples by means of two-photon excited fluorescence spectrum and lifetime imaging microscopy (FSIM/FLIM). By our first results, we characterized the autofluorescence of individual anatomical structures of porcine retina samples excited at 760 nm. The fluorescence properties of almost all investigated retinal layers are relatively homogenous. But as previously unknown, ganglion cell bodies show a significantly shorter fluorescence lifetime compared to the adjacent mueller cells. Since all retinal layers exhibit bi-exponential autofluorescence decays, we were able to achieve a more precise characterization of fluorescence properties of endogenous fluorophores compared to a present in vivo FLIM approach by confocal scanning laser ophthalmoscope (cSLO).

High-resolution optical coherence tomography, autofluorescence, and infrared reflectance imaging in Sjögren reticular dystrophy.

PubMed

Schauwvlieghe, Pieter-Paul; Torre, Kara Della; Coppieters, Frauke; Van Hoey, Anneleen; De Baere, Elfride; De Zaeytijd, Julie; Leroy, Bart P; Brodie, Scott E

2013-01-01

To describe the phenotype of three cases of Sjögren reticular dystrophy in detail, including high-resolution optical coherence tomography, autofluorescence imaging, and near-infrared reflectance imaging. Two unrelated teenagers were independently referred for ophthalmologic evaluation. Both underwent a full ophthalmologic workup, including electrophysiologic and extensive imaging with spectral-domain optical coherence tomography, autofluorescence imaging, and near-infrared reflectance imaging. In addition, mutation screening of ABCA4, PRPH2, and the mitochondrial tRNA gene was performed in Patient 1. Subsequently, the teenage sister of Patient 2 was examined. Strikingly similar phenotypes were present in these three patients. Fundoscopy showed bilateral foveal pigment alterations, and a lobular network of deep retinal, pigmented deposits throughout the posterior pole, tapering toward the midperiphery, with relative sparing of the immediate perifoveal macula and peripapillary area. This network is mildly to moderately hyperautofluorescent on autofluorescence and bright on near-infrared reflectance imaging. Optical coherence tomography showed abnormalities of the retinal pigment epithelium-Bruch membrane complex, photoreceptor outer segments, and photoreceptor inner/outer segment interface. The results of retinal function test were entirely normal. No molecular cause was detected in Patient 1. Imaging suggested that the lobular network of deep retinal deposits in Sjögren reticular dystrophy is the result of accumulation of both pigment and lipofuscin between photoreceptors and retinal pigment epithelium, as well as within the retinal pigment epithelium.

Inhibition or Stimulation of Autophagy Affects Early Formation of Lipofuscin-Like Autofluorescence in the Retinal Pigment Epithelium Cell

PubMed Central

Lei, Lei; Tzekov, Radouil; Li, Huapeng; McDowell, J. Hugh; Gao, Guangping; Smith, W. Clay; Tang, Shibo; Kaushal, Shalesh

2017-01-01

The accumulation of lipofuscin in the retinal pigment epithelium (RPE) is dependent on the effectiveness of photoreceptor outer segment material degradation. This study explored the role of autophagy in the fate of RPE lipofuscin degradation. After seven days of feeding with either native or modified rod outer segments, ARPE-19 cells were treated with enhancers or inhibitors of autophagy and the autofluorescence was detected by fluorescence-activated cell sorting. Supplementation with different types of rod outer segments increased lipofuscin-like autofluorescence (LLAF) after the inhibition of autophagy, while the induction of autophagy (e.g., application of rapamycin) decreased LLAF. The effects of autophagy induction were further confirmed by Western blotting, which showed the conversion of LC3-I to LC3-II, and by immunofluorescence microscopy, which detected the lysosomal activity of the autophagy inducers. We also monitored LLAF after the application of several autophagy inhibitors by RNA-interference and confocal microscopy. The results showed that, in general, the inhibition of the autophagy-related proteins resulted in an increase in LLAF when cells were fed with rod outer segments, which further confirms the effect of autophagy in the fate of RPE lipofuscin degradation. These results emphasize the complex role of autophagy in modulating RPE autofluorescence and confirm the possibility of the pharmacological clearance of RPE lipofuscin by small molecules. PMID:28353645

Intravital autofluorescence 2-photon microscopy of murine intestinal mucosa with ultra-broadband femtosecond laser pulse excitation: image quality, photodamage, and inflammation

NASA Astrophysics Data System (ADS)

Klinger, Antje; Krapf, Lisa; Orzekowsky-Schroeder, Regina; Koop, Norbert; Vogel, Alfred; Hüttmann, Gereon

2015-11-01

Ultra-broadband excitation with ultrashort pulses may enable simultaneous excitation of multiple endogenous fluorophores in vital tissue. Imaging living gut mucosa by autofluorescence 2-photon microscopy with more than 150 nm broad excitation at an 800-nm central wavelength from a sub-10 fs titanium-sapphire (Ti:sapphire) laser with a dielectric mirror based prechirp was compared to the excitation with 220 fs pulses of a tunable Ti:sapphire laser at 730 and 800 nm wavelengths. Excitation efficiency, image quality, and photochemical damage were evaluated. At similar excitation fluxes, the same image brightness was achieved with both lasers. As expected, with ultra-broadband pulses, fluorescence from NAD(P)H, flavines, and lipoproteins was observed simultaneously. However, nonlinear photodamage apparent as hyperfluorescence with functional and structural alterations of the tissue occurred earlier when the laser power was adjusted to the same image brightness. After only a few minutes, the immigration of polymorphonuclear leucocytes into the epithelium and degranulation of these cells, a sign of inflammation, was observed. Photodamage is promoted by the higher peak irradiances and/or by nonoptimal excitation of autofluorescence at the longer wavelength. We conclude that excitation with a tunable narrow bandwidth laser is preferable to ultra-broadband excitation for autofluorescence-based 2-photon microscopy, unless the spectral phase can be controlled to optimize excitation conditions.

Reference ranges of kidney dimensions in term newborns: sonographic measurements.

PubMed

Erdemir, Aydin; Kahramaner, Zelal; Arik, Bilal; Bilgili, Gokmen; Tekin, Mehmet; Genc, Yeliz

2014-11-01

Ultrasonographic measurement of kidney dimensions is important in evaluation of renal disease during the neonatal period, when renal abnormalities are common and renal size rapidly changes with age. To determine the reference ranges of kidney dimensions in newborns and to provide a reference chart for daily practice. In this prospective study, kidney dimensions were evaluated in 385 healthy newborns with a gestational age ≥37 weeks. Each neonate seen at an obstetrics clinic and neonatal intensive care unit was examined with sonography within the first week of life. Relationships of all dimensions with gender, gestational age, height and weight were statistically analyzed. All dimensions of the kidneys were smaller in girls than in boys (P < 0.05). The dimensions of the left kidney were larger than those in the right kidney in both genders (P < 0.01). Longitudinal and anteroposterior dimensions of the right and left kidneys showed no correlation with the gestational age in either gender. The dimensions correlated with the height in boys (P < 0.01), while no correlation was seen between the dimensions and height in girls (P < 0.05). Weight had the best correlation with all dimensions in both genders. The reference values of kidney lengths and diagrams from this study may be useful in the sonographic evaluation of kidneys in newborns.

Prevalence of acute kidney injury in intensive care units: the "COrte de prevalencia de disFunción RenAl y DEpuración en críticos" point-prevalence multicenter study.

PubMed

Herrera-Gutiérrez, Manuel E; Seller-Pérez, Gemma; Sánchez-Izquierdo-Riera, José A; Maynar-Moliner, Javier

2013-10-01

This study aimed to measure the point prevalence of kidney dysfunction (KD) in the intensive care setting. A point-prevalence, single-day, prospective study was conducted. Of 919 patients present in 42 Intensive care units (ICUs) for 2 specific days (September 2009 and March 2010), 832 cases were included. Mild KD was defined as a measured creatinine clearance of 90 to 60 mL min(-1) 1.73 m(-2), and severe KD was defined as a creatinine clearance less than 60 mL min(-1) 1.73 m(-2). Prevalence of mild KD was 15.9/100 patients/d (13.5-18.5), and severe KD was 42.4/100 patients/d (39.1-45.8). We considered as having a low probability of experiencing KD those patients without chronic kidney disease, acute kidney injury network stage 0, and a serum creatinine less than 1.2 mg/dL, but among them (557 patients), 18.1% (15.2%-21.6%) had mild KD and 24.2% (20.9%-28%) had severe KD. ICU mortality was 10.6% (7.81%-14.4%) for patients without dysfunction, 16.6% (11.2%-24%) for patients with mild KD, and 29.7% (25.2%-34.7%; P<.001) for patients with severe KD, with a relative risk for severe KD vs no KD of 2.54 (1.90-3.40). In 54.3% patients, at least 1 renal insult was reported. One nephrotoxic drug was administered to 34.4% and 2 or more to 14.9% patients, with a lower frequency among those with chronic kidney disease (30.6% vs 50.8%; P<.05). Each day of study, more that half of the patients admitted to the ICU showed some derangement in kidney function. More than 25% of patients not fulfilling the KD criteria by serum creatinine or acute kidney injury network showed, in fact, a severe KD, and this finding was associated with higher mortality. More than 50% of the patients admitted to the ICU were subjected to at least 1 renal insult. Copyright © 2013 Elsevier Inc. All rights reserved.

Skin autofluorescence and peripheral neuropathy four years later in type 1 diabetes.

PubMed

Rajaobelina, K; Farges, B; Nov, S; Maury, E; Cephise-Velayoudom, F L; Gin, H; Helmer, C; Rigalleau, V

2017-02-01

Advanced glycation end products (AGEs) are involved in diabetes complications. We aimed to investigate whether the accumulation of AGEs measured by skin autofluorescence (sAF) was associated with signs of diabetic peripheral neuropathy and to sensitivity, pain, motor and autonomic function 4 years later in patients with type 1 diabetes. At baseline, 188 patients (age 51 years, diabetes duration 22 years) underwent skin autofluorescence measurement using the AGE Reader. Four years later, signs of diabetic peripheral neuropathy were defined as the presence of neuropathic pain and/or feet sensory loss or foot ulceration. Neurological tests were systematically performed: vibration perception threshold by neuroesthesiometry, neuropathic pain by the Douleur Neuropathique en 4 Questions score, muscle strength by dynamometry and electrochemical skin conductance. Multivariate analyses were adjusted by age, sex, height, body mass index, tobacco, HbA 1c , diabetes duration, estimated glomerular filtration rate and albumin excretion rate. At the 4-year follow-up, 13.8% of patients had signs of diabetic peripheral neuropathy. The baseline sAF was higher in those with signs of diabetic peripheral neuropathy (2.5 ± 0.7 vs 2.1 ± 0.5 arbitrary units (AU), p < 0.0005). In the multivariate analysis, a 1 SD higher skin autofluorescence at baseline was associated with an increased risk of signs of neuropathy (OR = 2.68, p = 0.01). All of the neurological tests were significantly altered in the highest quartile of the baseline sAF (>2.4 AU) compared with the lowest quartiles after multivariate adjustment. This non-invasive measurement of skin autofluorescence may have a value for diabetic peripheral neuropathy in type 1 diabetes and a potential clinical utility for detection of diabetic peripheral neuropathy. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Prevalence of giant kidney worm (Dioctophyma renale) in wild mink (Mustela vison) in Minnesota

USGS Publications Warehouse

Mech, L. David; Tracy, Shawn P.

2001-01-01

Of 138 wild mink (Mustela vison) from eastern Minnesota, 27% contained Dioctophyma renale, primarily in the right kidney. No significant difference between prevalence in adult male and immature male mink was found, nor between the prevalence in males versus female mink. Thirteen worms were found in one male mink, representing the highest documented infection intensity of a single wild mink.

Pharmacological management of acute kidney injury and chronic kidney disease in neonates.

PubMed

Jetton, Jennifer G; Sorenson, Mark

2017-04-01

Both acute kidney injury (AKI) and chronic kidney disease (CKD) are seen more frequently in the neonatal intensive care unit (NICU) as advances in supportive care improve the survival of critically ill infants as well as those with severe, congenital kidney and urinary tract anomalies. Many aspects of the infant's care, including fluid balance, electrolyte and mineral homeostasis, acid-base balance, and growth and nutrition require close monitoring by and collaboration among neonatologists, nephrologists, dieticians, and pharmacologists. This educational review summarizes the therapies widely used for neonates with AKI and CKD. Use of these therapies is extrapolated from data in older children and adults or based on clinical experience and case series. There is a critical need for more research on the use of therapies in infants with kidney disease as well as for the development of drug delivery systems and preparations scaled more appropriately for these small patients. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multiphoton Absorption is Probably Not the Primary Threshold Damage Mechanism for Femtosecond Laser Pulse Exposures in the Retinal Pigment Epithelium

DTIC Science & Technology

2004-01-01

Tromberg, and E. Gratton, "Two-photon excited lifetime imaging of autofluorescence in cells during UTVA and NIR photostress", J. Micros. 183, pp. 197-204...1996. 4. K. Konig, Y. Liu, G. J. Sonek, M. W. Berns, and B. J. Tromberg, " Autofluorescence spectroscopy of optically trapped cells", Photochem...34, Photochem. Photobiol. 70, pp. 146-151, 1999. 10. R. D. Glickman, "Phototoxicity to the retina : Mechanisms of damage", International Journal of

Full Modeling of High-Intensity Focused Ultrasound and Thermal Heating in the Kidney Using Realistic Patient Models.

PubMed

Suomi, Visa; Jaros, Jiri; Treeby, Bradley; Cleveland, Robin O

2018-05-01

High-intensity focused ultrasound (HIFU) therapy can be used for noninvasive treatment of kidney (renal) cancer, but the clinical outcomes have been variable. In this study, the efficacy of renal HIFU therapy was studied using nonlinear acoustic and thermal simulations in three patients. The acoustic simulations were conducted with and without refraction in order to investigate its effect on the shape, size, and pressure distribution at the focus. The values for the attenuation, sound speed, perfusion, and thermal conductivity of the kidney were varied over the reported ranges to determine the effect of variability on heating. Furthermore, the phase aberration was studied in order to quantify the underlying phase shifts using a second-order polynomial function. The ultrasound field intensity was found to drop on average 11.1 dB with refraction and 6.4 dB without refraction. Reflection at tissue interfaces was found to result in a loss less than 0.1 dB. Focal point splitting due to refraction significantly reduced the heating efficacy. Of all the tissue parameters, perfusion was found to affect the heating the most. Small changes in temperature were seen with varying attenuation and thermal conductivity, but no visible changes were present with sound speed variations. The aberration study revealed an underlying trend in the spatial distribution of the phase shifts. The results show that the efficacy of HIFU therapy in the kidney could be improved with aberration correction. A method is proposed by which patient specific pretreatment calculations could be used to overcome the aberration and therefore make ultrasound treatment possible.

Tumor cell differentiation by label-free microscopy

NASA Astrophysics Data System (ADS)

Schneckenburger, Herbert; Weber, Petra; Wagner, Michael

2013-05-01

Autofluorescence and Raman measurements of U251-MG glioblastoma cells prior and subsequent to activation of tumor suppressor genes are compared. While phase contrast images and fluorescence intensity patterns of the tumor (control) cells and the less malignant cells are similar, differences can be deduced from fluorescence spectra and nanosecond decay times. In particular, upon excitation around 375nm, the fluorescence ratio of the protein bound and the free coenzyme NADH depends on the state of malignancy and reflects different cytoplasmic (including lysosomal) and mitochondrial contributions. Slight differences are also observed in the Raman spectra of these cell lines, mainly originating from small granules (lysosomes) surrounding the cell nucleus. While larger numbers of fluorescence and Raman spectra are evaluated by multivariate statistical methods, additional information is obtained from spectral images and fluorescence lifetime images (FLIM).

Fluorescent-Spectroscopic Research of in Vivo Tissues Pathological Conditions

NASA Astrophysics Data System (ADS)

Giraev, K. M.; Ashurbekov, N. A.; Medzhidov, R. T.

The steady-state spectra of autofluorescence and the reflection coefficient on the excitation wavelength of some stomach tissues in vivo with various pathological conditions (surface gastritis, displasia, cancer) are measured under excitation by the nitrogen laser irradiation (λex=337.1 nm). The contour expansion of obtained fluorescence spectra into contributions of components is conducted by the Gaussian-Lorentzian curves method. It is shown that at least 7 groups of fluorophores forming a total luminescence spectrum can be distinguished during the development of displasia and tumor processes. The correlation of intensities of flavins and NAD(P)·H fluorescence is determined and the degree of respiratory activity of cells for the functional condition considered is estimated. The evaluations of the fluorescence quantum yield of the tissue's researched are given.

Stationary spectroscopy of biotissues in vivo: Fluorescent studies of some pathological states

NASA Astrophysics Data System (ADS)

Giraev, K. M.; Ashurbekov, N. A.; Medzhidov, R. T.

2003-11-01

The stationary spectra of autofluorescence, along with the reflection coefficient at the wavelength of excitation, are measured in vivo for some stomach tissues in the case of different pathological states (dysplasia, superficial gastritis, and cancer) using a nitrogen laser as the source of excitation (λrad=337.1 nm). The fluorescence spectra obtained are decomposed into Gaussian-Lorentzian components. It is found that, in development of dysplasia and tumor processes, at least seven groups of fluorophores can be distinguished that form the entire emission spectrum. The ratio between the fluorescence intensities of flavins and NAD(P)H is determined and the degree of respiratory activity of cells estimated for the states considered. The quantum yields of fluorescence of the biotissues under investigation are estimated.

Kidney pericytes: roles in regeneration and fibrosis.

PubMed

Kramann, Rafael; Humphreys, Benjamin D

2014-07-01

Renal pericytes have been neglected for many years, but recently they have become an intensively studied cell population in renal biology and pathophysiology. Pericytes are stromal cells that support vasculature, and a subset of pericytes are mesenchymal stem cells. In kidney, pericytes have been reported to play critical roles in angiogenesis, regulation of renal medullary and cortical blood flow, and serve as progenitors of interstitial myofibroblasts in renal fibrogenesis. They interact with endothelial cells through distinct signaling pathways and their activation and detachment from capillaries after acute or chronic kidney injury may be critical for driving chronic kidney disease progression. By contrast, during kidney homeostasis it is likely that pericytes serve as a local stem cell population that replenishes differentiated interstitial and vascular cells lost during aging. This review describes both the regenerative properties of pericytes as well as involvement in pathophysiologic conditions such as fibrogenesis. Copyright © 2014 Elsevier Inc. All rights reserved.

Hemolysis in a patient with alkaptonuria and chronic kidney failure.

PubMed

Heng, Anne-Elisabeth; Courbebaisse, Marie; Kemeny, Jean Louis; Matesan, Raluca; Bonniol, Claude; Deteix, Patrice; Souweine, Bertrand

2010-07-01

In alkaptonuria, the absence of homogentisic acid oxidase results in the accumulation of homogentisic acid (HGA) in the body. Fatal disease cases are infrequent, and death often results from kidney or cardiac complications. We report a 24-year-old alkaptonuric man with severe decreased kidney function who developed fatal metabolic acidosis and intravascular hemolysis. Hemolysis may have been caused by rapid and extensive accumulation of HGA and subsequent accumulation of plasma soluble melanins. Toxic effects of plasma soluble melanins, their intermediates, and reactive oxygen side products are increased when antioxidant mechanisms are overwhelmed. A decrease in serum antioxidative activity has been reported in patients with chronic decreased kidney function. However, despite administration of large doses of an antioxidant agent and ascorbic acid and intensive kidney support, hemolysis and acidosis could not be brought under control and hemolysis led to the death of the patient.

Balanced crystalloids versus saline in the intensive care unit: study protocol for a cluster-randomized, multiple-crossover trial.

PubMed

Semler, Matthew W; Self, Wesley H; Wang, Li; Byrne, Daniel W; Wanderer, Jonathan P; Ehrenfeld, Jesse M; Stollings, Joanna L; Kumar, Avinash B; Hernandez, Antonio; Guillamondegui, Oscar D; May, Addison K; Siew, Edward D; Shaw, Andrew D; Bernard, Gordon R; Rice, Todd W

2017-03-16

Saline, the intravenous fluid most commonly administered to critically ill adults, contains a high chloride content, which may be associated with acute kidney injury and death. Whether using balanced crystalloids rather than saline decreases the risk of acute kidney injury and death among critically ill adults remains unknown. The Isotonic Solutions and Major Adverse Renal Events Trial (SMART) is a pragmatic, cluster-level allocation, cluster-level crossover trial being conducted between 1 June 2015 and 30 April 2017 in five intensive care units at Vanderbilt University Medical Center in Nashville, TN, USA. SMART compares saline (0.9% sodium chloride) with balanced crystalloids (clinician's choice of lactated Ringer's solution or Plasma-Lyte A®). Each intensive care unit is assigned to provide either saline or balanced crystalloids each month, with the assigned crystalloid alternating monthly over the course of the trial. All adults admitted to participating intensive care units during the study period are enrolled and followed until hospital discharge or 30 days after enrollment. The anticipated enrollment is approximately 14,000 patients. The primary outcome is Major Adverse Kidney Events within 30 days-the composite of in-hospital death, receipt of new renal replacement therapy, or persistent renal dysfunction (discharge creatinine ≥200% of baseline creatinine). Secondary clinical outcomes include in-hospital mortality, intensive care unit-free days, ventilator-free days, vasopressor-free days, and renal replacement therapy-free days. Secondary renal outcomes include new renal replacement therapy receipt, persistent renal dysfunction, and incidence of stage 2 or higher acute kidney injury. This ongoing pragmatic trial will provide the largest and most comprehensive comparison to date of clinical outcomes with saline versus balanced crystalloids among critically ill adults. For logistical reasons, SMART was prospectively registered separately for the medical ICU (SMART-MED; ClinicalTrials.gov identifier: NCT02444988 ; registered on 11 May 2015; date of first patient enrollment: 1 June 2015) and the nonmedical ICUs (SMART-SURG; ClinicalTrials.gov identifier: NCT02547779 ; registered on 9 September 2015; date of first patient enrollment: 1 October 2015).

Fundus autofluorescence imaging in dry AMD: 2014 Jules Gonin lecture of the Retina Research Foundation.

PubMed

Holz, Frank G; Steinberg, Julia S; Göbel, Arno; Fleckenstein, Monika; Schmitz-Valckenberg, Steffen

2015-01-01

Fundus autofluorescence (FAF) imaging allows for topographic mapping of intrisnic fluorophores in the retinal pigment epithelial cell monolayer, as well as mapping of other fluorophores that may occur with disease in the outer retina and the sub-neurosensory space. FAF imaging provides information not obtainable with other imaging modalities. Near-infrared fundus autofluorescence images can also be obtained in vivo, and may be largely melanin-derived. FAF imaging has been shown to be useful in a wide spectrum of macular and retinal diseases. The scope of applications now includes identification of diseased RPE in macular/retinal diseases, elucidating pathophysiological mechanisms, identification of early disease stages, refined phenotyping, identification of prognostic markers for disease progression, monitoring disease progression in the context of both natural history and interventional therapeutic studies, and objective assessment of luteal pigment distribution and density as well as RPE melanin distribution. Here, we review the use of FAF imaging in various phenotypic manifestations of dry AMD.

Far-Red Fluorescent Lipid-Polymer Probes for an Efficient Labeling of Enveloped Viruses.

PubMed

Lacour, William; Adjili, Salim; Blaising, Julie; Favier, Arnaud; Monier, Karine; Mezhoud, Sarra; Ladavière, Catherine; Place, Christophe; Pécheur, Eve-Isabelle; Charreyre, Marie-Thérèse

2016-08-01

Far-red emitting fluorescent lipid probes are desirable to label enveloped viruses, for their efficient tracking by optical microscopy inside autofluorescent cells. Most used probes are rapidly released from membranes, leading to fluorescence signal decay and loss of contrast. Here, water-soluble lipid-polymer probes are synthesized harboring hydrophilic or hydrophobic far-red emitting dyes, and exhibiting enhanced brightness. They efficiently label Hepatitis C Virus pseudotyped particles (HCVpp), more stably and reproducibly than commercial probes, and a strong fluorescence signal is observed with a high contrast. Labeling with such probes do not alter virion morphology, integrity, nor infectivity. Finally, it is shown by fluorescence microscopy that these probes enable efficient tracking of labeled HCVpp inside hepatocarcinoma cells used as model hepatocytes, in spite of their autofluorescence up to 700 nm. These novel fluorescent lipid-polymer probes should therefore enable a better characterization of early stages of infection of autofluorescent cells by enveloped viruses. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In vivo two-photon imaging of macrophage activities in skeletal muscle regeneration

NASA Astrophysics Data System (ADS)

Qin, Zhongya; Long, Yanyang; Sun, Qiqi; He, Sicong; Li, Xuesong; Chen, Congping; Wu, Zhenguo; Qu, Jianan Y.

2018-02-01

Macrophages are essential for the regeneration of skeletal muscle after injury. It has been demonstrated that depletion of macrophages results in delay of necrotic fiber phagocytosis and decreased size of regenerated myofibers. In this work, we developed a multi-modal two-photon microscope system for in vivo study of macrophage activities in the regenerative and fibrotic healing process of injured skeletal muscles. The system is capable to image the muscles based on the second harmonic generation (SHG) and two-photon excited fluorescence (TPEF) signals simultaneously. The dynamic activities of macrophages and muscle satellite cells are recorded in different time windows post the muscle injury. Moreover, we found that infiltrating macrophages emitted strong autofluorescence in the injured skeletal muscle of mouse model, which has not been reported previously. The macrophage autofluorescence was characterized in both spectral and temporal domains. The information extracted from the autofluorescence signals may facilitate the understanding on the formation mechanisms and possible applications in biological research related to skeletal muscle regeneration.

Ultra-Wide-Field Fundus Autofluorescence and Spectral-Domain Optical Coherence Tomography Findings in Syphilitic Outer Retinitis.

PubMed

Saleh, Mohamed G A; Campbell, John Peter; Yang, Paul; Lin, Phoebe

2017-03-01

To determine the ultra-wide-field fundus autofluorescence (UWFFAF) and optical coherence tomography (OCT) features of syphilitic outer retinopathy (SOR). Retrospective chart review. Three patients with SOR were investigated. Treatment with parenteral penicillin led to improvement of outer retinopathy, visual acuity, and symptoms. UWFFAF showed speckled hyperautofluorescence, hypoautofluorescence, and normal autofluorescence, similar to what has been described as a trizonal pattern in acute zonal occult outer retinopathy (AZOOR) in the chronic case of SOR, but with hyperautofluorescent areas in the two acute cases. OCT showed disruption of the photoreceptor outer segment ellipsoid zone and external limiting membrane, which improved after penicillin treatment, and corresponded to normalization of the hyperautofluorescent areas on UWFFAF. There was irregularity and nodular thickening of retinal pigment epithelium on OCT in areas of mottled hyperautofluorescence. SOR can present similarly to AZOOR on UWFFAF and should be highly suspected in cases presenting like AZOOR. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:208-215. ]. Copyright 2017, SLACK Incorporated.

Topical timolol with and without benzalkonium chloride: epithelial permeability and autofluorescence of the cornea in glaucoma.

PubMed

de Jong, C; Stolwijk, T; Kuppens, E; de Keizer, R; van Best, J

1994-04-01

Epithelial permeability and autofluorescence of the cornea were determined by fluorophotometry in 21 patients with open-angle glaucoma or ocular hypertension using timolol medication with the preservative benzalkonium chloride (BAC) and 2 weeks after changing to timolol medication without BAC. The investigation was performed to determine whether removal of BAC would reduce toxic effects on the cornea and complaints of sensations of burning or dry eye. Corneal epithelial permeability decreased significantly after changing medication (mean decrease per patient 27%, P = 0.025). Corneal autofluorescence increased significantly after changing medication suggesting an alteration in corneal metabolism (mean increase per patient 6%, P = 0.003). Timolol without BAC was found to be as effective as timolol with BAC in reducing intraocular pressure (P = 0.4). Removal of BAC from timolol resulted in an improvement of corneal epithelial barrier function and in a reduction of complaints. The improvement was found to be proportional to the duration of the preceding BAC-containing therapy.

Intravital imaging by simultaneous label-free autofluorescence-multiharmonic microscopy.

PubMed

You, Sixian; Tu, Haohua; Chaney, Eric J; Sun, Yi; Zhao, Youbo; Bower, Andrew J; Liu, Yuan-Zhi; Marjanovic, Marina; Sinha, Saurabh; Pu, Yang; Boppart, Stephen A

2018-05-29

Intravital microscopy (IVM) emerged and matured as a powerful tool for elucidating pathways in biological processes. Although label-free multiphoton IVM is attractive for its non-perturbative nature, its wide application has been hindered, mostly due to the limited contrast of each imaging modality and the challenge to integrate them. Here we introduce simultaneous label-free autofluorescence-multiharmonic (SLAM) microscopy, a single-excitation source nonlinear imaging platform that uses a custom-designed excitation window at 1110 nm and shaped ultrafast pulses at 10 MHz to enable fast (2-orders-of-magnitude improvement), simultaneous, and efficient acquisition of autofluorescence (FAD and NADH) and second/third harmonic generation from a wide array of cellular and extracellular components (e.g., tumor cells, immune cells, vesicles, and vessels) in living tissue using only 14 mW for extended time-lapse investigations. Our work demonstrates the versatility and efficiency of SLAM microscopy for tracking cellular events in vivo, and is a major enabling advance in label-free IVM.

In-vivo mapping of drusen by fundus autofluorescence and spectral-domain optical coherence tomography imaging.

PubMed

Göbel, Arno P; Fleckenstein, Monika; Heeren, Tjebo F C; Holz, Frank G; Schmitz-Valckenberg, Steffen

2016-01-01

To determine fundus autofluorescence (FAF) signal variations and corresponding microstructural alterations on spectral-domain optical coherence tomography (SD-OCT) in areas of funduscopically visible drusen associated with age-related macular degeneration (AMD). Thirty eyes from 22 patients with geographic atrophy (GA) secondary to AMD (median age 74, range 64-87 years), who had undergone retinal imaging including color fundus photography (CFP), FAF and SD-OCT (Spectralis HRA+OCT; Heidelberg Engineering GmbH, Heidelberg, Germany) were retrospectively analyzed. In each eye, at least one druse (≥ 63 μm) in the perilesional zone of GA recorded on CFP was analyzed. Relative FAF intensities and alterations in SD-OCT bands at the site of each druse were evaluated. A total of 73 drusen were analyzed, which were associated with heterogeneous corresponding alterations on FAF and SD-OCT. The FAF signal was normal, increased, decreased or not evaluable in 32 (44 %), 27 (37 %), 12 (16 %), and 2 (3 %) drusen, respectively. Focal hyperreflectivity overlying drusen was most frequently spatially confined to increased FAF (present in 9 (33 %) of 27 drusen with increased FAF). Outer nuclear layer thinning and choroidal hyperreflectivity were associated with decreased FAF (present in 7 [58 %] of 12 and 6 [50 %] of 12 drusen with decreased FAF, respectively). The appearance of soft drusen on CFP does not allow for differentiation between preserved and markedly compromised outer retinal integrity, including incipient atrophy and focal neurosensory alterations of reflectivity overlying extracellular sub-retinal pigment epithelium (RPE) deposits. Multimodal imaging reveals a broad spectrum of microstructural changes, which may reflect different stages in the evolution of drusen.

Quantitative Multispectral Analysis Of Discrete Subcellular Particles By Digital Imaging Fluorescence Microscopy (DIFM)

NASA Astrophysics Data System (ADS)

Dorey, C. K.; Ebenstein, David B.

1988-10-01

Subcellular localization of multiple biochemical markers is readily achieved through their characteristic autofluorescence or through use of appropriately labelled antibodies. Recent development of specific probes has permitted elegant studies in calcium and pH in living cells. However, each of these methods measured fluorescence at one wavelength; precise quantitation of multiple fluorophores at individual sites within a cell has not been possible. Using DIFM, we have achieved spectral analysis of discrete subcellular particles 1-2 gm in diameter. The fluorescence emission is broken into narrow bands by an interference monochromator and visualized through the combined use of a silicon intensified target (SIT) camera, a microcomputer based framegrabber with 8 bit resolution, and a color video monitor. Image acquisition, processing, analysis and display are under software control. The digitized image can be corrected for the spectral distortions induced by the wavelength dependent sensitivity of the camera, and the displayed image can be enhanced or presented in pseudocolor to facilitate discrimination of variation in pixel intensity of individual particles. For rapid comparison of the fluorophore composition of granules, a ratio image is produced by dividing the image captured at one wavelength by that captured at another. In the resultant ratio image, a granule which has a fluorophore composition different from the majority is selectively colored. This powerful system has been utilized to obtain spectra of endogenous autofluorescent compounds in discrete cellular organelles of human retinal pigment epithelium, and to measure immunohistochemically labelled components of the extracellular matrix associated with the human optic nerve.

Effects of cadmium metal on young gametophytes of Gelidium floridanum: metabolic and morphological changes.

PubMed

Simioni, Carmen; Schmidt, Éder C; Rover, Ticiane; dos Santos, Rodrigo; Filipin, Elisa P; Pereira, Debora T; Costa, Giulia Burle; Oliveira, Eva Regina; Chow, Fungyi; Ramlov, Fernanda; Ouriques, Luciane; Maraschin, Marcelo; Bouzon, Zenilda L

2015-09-01

By evaluating carotenoid content, photosynthetic pigments and changes in cellular morphology, growth rates, and photosynthetic performance, this study aimed to determine the effect of cadmium (Cd) on the development of young gametophytes of Gelidium floridanum. Plants were exposed to 7.5 and 15 μM of Cd for 7 days. Control plants showed increased formation of new filamentous thallus, increased growth rates, presence of starch grains in the cortical and subcortical cells, protein content distributed regularly throughout the cell periphery, and intense autofluorescence of chloroplasts. On the other hand, plants treated with Cd at concentrations of 7.5 and 15 μM showed few formations of new thallus with totally depigmented regions, resulting in decreased growth rates. Plants exposed to 7.5 μM Cd demonstrated alterations in the cell wall and an increase in starch grains in the cortical and subcortical cells, while plants exposed to 15 μM Cd showed changes in medullary cells with no organized distribution of protein content. The autofluorescence and structure of chloroplasts decreased, forming a thin layer on the periphery of cells. Cadmium also affected plant metabolism, as visualized by a decrease in photosynthetic pigments, in particular, phycoerythrin and phycocyanin contents, and an increase in carotenoids. This result agrees with decreased photosynthetic performance and chronic photoinhibition observed after treatment with Cd, as measured by the decrease in electron transport rate. Based on these results, it was concluded that exposure to Cd affects cell metabolism and results in significant toxicity to young gametophytes of G. floridanum.

Blood interference in fiber-optical based fluorescence guided resection of glioma using 5-aminolevulinic acid

NASA Astrophysics Data System (ADS)

Haj-Hosseini, Neda; Lowndes, Shannely; Salerud, Göran; Wårdell, Karin

2011-03-01

Fluorescence guidance in brain tumor resection is performed intra-operatively where bleeding is included. When using fiber-optical probes, the transmission of light to and from the tissue is totally or partially blocked if a small amount of blood appears in front of the probe. Sometimes even after rinsing with saline, the remnant blood cells on the optical probe head, disturb the measurements. In such a case, the corresponding spectrum cannot be reliably quantified and is therefore discarded. The optimal case would be to calculate and take out the blood effect systematically from the collected signals. However, the first step is to study the pattern of blood interference in the fluorescence spectrum. In this study, a fiber-optical based fluorescence spectroscopy system with a laser excitation light of 405 nm (1.4 J/cm2) was used during fluorescence guided brain tumor resection using 5-aminolevulinic acid (5-ALA). The blood interference pattern in the fluorescence spectrum collected from the brain was studied in two patients. The operation situation was modeled in the laboratory by placing blood drops from the finger tip on the skin of forearm and the data was compared to the brain in vivo measurements. Additionally, a theoretical model was developed to simulate the blood interference pattern on the skin autofluorescence. The blood affects the collected fluorescence intensity and leaves traces of oxy and deoxy-hemoglobin absorption peaks. According to the developed theoretical model, the autofluorescence signal is considered to be totally blocked by an approximately 500 μm thick blood layer.

Laser-induced autofluorescence properties of base-cell lesions: analysis and algorithms for diagnosis and differentiation

NASA Astrophysics Data System (ADS)

Borisova, E.; Troyanova, P.; Avramov, L.

2006-09-01

The goals of this work were investigation of base-cell skin lesions by the method of laser-induced autofluorescence spectroscopy. Fluorescence spectra were obtained from benign base-cell papilloma and malignant base-cell carcinoma, as well as from healthy skin areas near to the lesions that were used posteriori to reveal changes between healthy and lesion skin spectra. Preliminarily lesions were classified by dermatoscopic method (MoleMax II, DERMA Instruments). All suspicious lesions were excised and were investigated histologically. The experimental set-up consists of a nitrogen laser (337 nm, 14 μJ, 10 Hz), lenses, filters, optical fibers, and a microspectrometer (PC2000, "Ocean Optics"). A computer controls this system. Spectrum of healthy skin consists of one main maximum at 470-500 nm spectral region and secondary maxima at in the regions around 400 and 440 nm. In cases of papilloma and base-cell carcinoma an intensity decrease was observed, related to accumulation of pigments in these cutaneous lesions. An relative increase of the fluorescence peak at 440 nm were registered in the case of base-cell carcinoma, related to metabolism activity increase, and appearance of green fluorescence, related to increase of keratin content in benign papilloma lesions were detected. The results, obtained were used to develop multispectral diagnostic algorithm of these base-cell lesions. An sensitivity of 89,4% and 91,0% and specificity of 99,6% and 97,4% for differentiation between normal skin and papilloma and carcinoma respectively were obtained. The capability of the human skin fluorescence spectroscopy for early diagnosis and differentiation of cutaneous lesions is shown.

Polarization effects in cutaneous autofluorescent spectra

NASA Astrophysics Data System (ADS)

Borisova, E.; Angelova, L.; Jeliazkova, Al.; Genova, Ts.; Pavlova, E.; Troyanova, P.; Avramov, L.

2014-05-01

Used polarized light for fluorescence excitation one could obtain response related to the anisotropy features of extracellular matrix. The fluorophore anisotropy is attenuated during lesions' growth and level of such decrease could be correlated with the stage of tumor development. Our preliminary investigations are based on in vivo point-by-point measurements of excitation-emission matrices (EEM) from healthy volunteers skin on different ages and from different anatomical places using linear polarizer and analyzer for excitation and emission light detected. Measurements were made using spectrofluorimeter FluoroLog 3 (HORIBA Jobin Yvon, France) with fiber-optic probe in steady-state regime using excitation in the region of 280-440 nm. Three different situations were evaluated and corresponding excitation-emission matrices were developed - with parallel and perpendicular positions for linear polarizer and analyzer, and without polarization of excitation and fluorescence light detected from a forearm skin surface. The fluorescence spectra obtained reveal differences in spectral intensity, related to general attenuation, due to filtering effects of used polarizer/analyzer couple. Significant spectral shape changes were observed for the complex autofluorescence signal detected, which correlated with collagen and protein cross-links fluorescence, that could be addressed to the tissue extracellular matrix and general condition of the skin investigated, due to morphological destruction during lesions' growth. A correlation between volunteers' age and the fluorescence spectra detected was observed during our measurements. Our next step is to increase developed initial database and to evaluate all sources of intrinsic fluorescent polarization effects and found if they are significantly altered from normal skin to cancerous state of the tissue, this way to develop a non-invasive diagnostic tool for dermatological practice.

Standardized deceased donor kidney donation rates in the UK reveal marked regional variation and highlight the potential for increasing kidney donation: a prospective cohort study†

PubMed Central

Summers, D. M.; Johnson, R. J.; Hudson, A. J.; Collett, D.; Murphy, P.; Watson, C. J. E.; Neuberger, J. M.; Bradley, J. A.

2014-01-01

Background The UK has implemented a national strategy for organ donation that includes a centrally coordinated network of specialist nurses in organ donation embedded in all intensive care units and a national organ retrieval service for deceased organ donors. We aimed to determine whether despite the national approach to donation there is significant regional variation in deceased donor kidney donation rates. Methods The UK prospective audit of deaths in critical care was analysed for a cohort of patients who died in critical care between April 2010 and December 2011. Multivariate logistic regression was used to identify the factors associated with kidney donation. The logistic regression model was then used to produce risk-adjusted funnel plots describing the regional variation in donation rates. Results Of the 27 482 patients who died in a critical care setting, 1528 (5.5%) became kidney donors. Factors found to influence donation rates significantly were: type of critical care [e.g. neurointensive vs general intensive care: OR 1.53, 95% confidence interval (CI) 1.34–1.75, P<0.0001], patient ethnicity (e.g. ‘Asian’ vs ‘white’: OR 0.17, 95% CI 0.11–0.26, P<0.0001), age (e.g. age >69 vs age 18–39 yr: OR 0.2, 0.15–0.25, P<0.0001), and cause of death [e.g. ‘other’ (excluding ‘stroke’ and ‘trauma’) vs ‘trauma’: OR 0.04, 95% CI 0.03–0.05, P<0.0001]. Despite correction for these variables, kidney donation rates for the 20 UK kidney donor regions showed marked variation. The overall standardized donation rate ranged from 3.2 to 7.5%. Four regions had donation rates of >2 standard deviations (sd) from the mean (two below and two above). Regional variation was most marked for donation after circulatory death (DCD) kidney donors with 9 of the 20 regions demonstrating donation rates of >2 sd from the mean (5 below and 4 above). Conclusions The marked regional variation in kidney donation rates observed in this cohort after adjustment for factors strongly associated with donation rates suggests that there is considerable scope for further increasing kidney donation rates in the UK, particularly DCD. PMID:24335581

Spectral domain optical coherence tomography and fundus autofluorescence findings in cytomegalovirus retinitis in HIV-infected patients.

PubMed

Yashiro, Shigeko; Nishijima, Takeshi; Yamamoto, Yuuka; Sekine, Yumi; Yoshida-Hata, Natsuyo; Iida, Tomohiro; Oka, Shinichi

2018-05-01

To assess the usefulness of spectral domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF) findings in cytomegalovirus (CMV) retinitis. Observational case series. Thirteen eyes of 11 human immunodeficiency virus (HIV)-positive patients with CMV retinitis underwent full ophthalmologic examinations, SD-OCT, and 4 eyes of 4 patients underwent FAF. FAF images included short-wavelength autofluorescence (SW-AF) and near-infrared autofluorescence (IR-AF). CMV retinitis was classified into proposed categories of acute, subacute, remission, and recurrent; the acute stage was further subdivided into initial, early, and late stages. In the initial stage, vertical structural disruption of all retinal layers was observed by SD-OCT, and FAF showed hyperautofluorescence on SW-AF and hypoautofluorescence on IR-AF. In the early stage, SD-OCT showed significant retinal thickening; cells and debris from the retinal surface to the vitreous; enlarged vessels with/without thickened vessel walls; and highly complicated serous retinal detachment. In the late to subacute stage, features observed included rhegmatogenous retinal detachment with shrinking posterior hyaloid membrane and waving from the ellipsoid zone to the retinal pigment epithelium. In remission, FAF findings were hypoautofluorescence on SW-AF and hyperautofluorescence on IR-AF. Although the number of examined eyes was limited, SD-OCT and FAF provide new information in various stages of CMV retinitis in patients with HIV infection that is not obtainable by conventional examination and which may be of great benefit when screening for the initial stage of CMV retinitis.

Two-Photon Autofluorescence Imaging Reveals Cellular Structures Throughout the Retina of the Living Primate Eye.

PubMed

Sharma, Robin; Williams, David R; Palczewska, Grazyna; Palczewski, Krzysztof; Hunter, Jennifer J

2016-02-01

Although extrinsic fluorophores can be introduced to label specific cell types in the retina, endogenous fluorophores, such as NAD(P)H, FAD, collagen, and others, are present in all retinal layers. These molecules are a potential source of optical contrast and can enable noninvasive visualization of all cellular layers. We used a two-photon fluorescence adaptive optics scanning light ophthalmoscope (TPF-AOSLO) to explore the native autofluorescence of various cell classes spanning several layers in the unlabeled retina of a living primate eye. Three macaques were imaged on separate occasions using a custom TPF-AOSLO. Two-photon fluorescence was evoked by pulsed light at 730 and 920 nm excitation wavelengths, while fluorescence emission was collected in the visible range from several retinal layers and different locations. Backscattered light was recorded simultaneously in confocal modality and images were postprocessed to remove eye motion. All retinal layers yielded two-photon signals and the heterogeneous distribution of fluorophores provided optical contrast. Several structural features were observed, such as autofluorescence from vessel walls, Müller cell processes in the nerve fibers, mosaics of cells in the ganglion cell and other nuclear layers of the inner retina, as well as photoreceptor and RPE layers in the outer retina. This in vivo survey of two-photon autofluorescence throughout the primate retina demonstrates a wider variety of structural detail in the living eye than is available through conventional imaging methods, and broadens the use of two-photon imaging of normal and diseased eyes.

Correlation between fundus autofluorescence and central visual function in chronic central serous chorioretinopathy.

PubMed

Eandi, Chiara M; Piccolino, Felice Cardillo; Alovisi, Camilla; Tridico, Federico; Giacomello, Daniela; Grignolo, Federico M

2015-04-01

To find possible correlations between the morphologic macular changes revealed by fundus autofluorescence (FAF) and the functional parameters such as visual acuity and retinal sensitivity in patients with chronic central serous chorioretinopathy (CSC). Prospective, cross-sectional study. Forty-six eyes (39 consecutive patients) with chronic CSC were studied with FAF and microperimetry (MP). Retinal sensitivity value maps were exactly superimposed over FAF images. The following microperimetric parameters were applied: central 10-degree visual field, 4-2-1 strategy, 61 stimulation spots, white monochromatic background, stimulation time 200 ms, stimulation spot size Goldmann III. A possible relationship between MP and FAF was investigated. Mean best-corrected visual acuity (BCVA) was 20/32 (median 20/25, range 20/20-20/200). BCVA was significantly correlated with FAF findings (Mann-Whitney test; P < .0001). A positive concordance between FAF and MP evaluation was also found (total concordance of 0.720 with a kappa of Cohen of 0.456). The hypo-autofluorescent areas showed decreased retinal sensitivity, while adjacent areas of increased FAF could be associated to both normal and decreased retinal sensitivity. Absolute scotoma, defined as 0 dB retinal sensitivity, corresponded with absence of autofluorescence. Altered FAF in chronic CSC patients has a functional correlation quantified by microperimetry. This study confirms the impact of FAF changes on retinal sensitivity and their value to reflect the functional impairment in chronic CSC. Copyright © 2015 Elsevier Inc. All rights reserved.

MULTIPLE EVANESCENT WHITE DOT SYNDROME WITH SUBRETINAL DEPOSITS.

PubMed

Gal-Or, Orly; Sorenson, John A; Gattoussi, Sarra; Dolz-Marco, Rosa; Freund, K Bailey

2017-06-13

To describe the multimodal imaging findings of transient subretinal deposits occurring in multiple evanescent white dot syndrome (MEWDS). The multimodal imaging characteristics of transient subretinal deposits occurring in MEWDS were investigated with ultra-widefield color and fundus autofluorescence, cross-sectional and en-face optical coherence tomography (OCT), en face OCT-angiography, and quantitative autofluorescence. A 28-year-old woman presented with photopsia and temporal visual field loss in her right eye. Her best-corrected visual acuity was 20/20 in her right eye and 20/25 in her left eye. Funduscopic examination showed characteristic peripapillary hyperautofluorescent white dots of MEWDS corresponding to ellipsoid zone disruption on OCT. These lesions became confluent throughout the posterior fundus over the next 4 weeks. As the patient's symptoms were resolving, a second type of transient hyperautofluorescent lesion was noted which corresponded to hyperreflective subretinal deposits on cross-sectional and en face structural OCT. These subretinal deposits were most evident at 10-week follow-up and had nearly resolved at 14-week follow-up. Quantitative autofluorescence showed that, unlike the acute MEWDS lesions, the hyperautoflurescence of the subretinal deposits persisted after photobleaching. At multiple time points over 14 weeks of follow-up, OCT angiography showed no evidence of retinal or choroidal flow abnormalities. Transient subretinal deposits may develop during MEWDS in areas of previous diffuse outer retinal disruption. As these deposits remain hyperautoflurescent on quantitative autofluorescence after photobleaching, they may represent accumulations of debris originating from damaged photoreceptor outer segments.

Demystifying autofluorescence with excitation scanning hyperspectral imaging

NASA Astrophysics Data System (ADS)

Deal, Joshua; Harris, Bradley; Martin, Will; Lall, Malvika; Lopez, Carmen; Rider, Paul; Boudreaux, Carole; Rich, Thomas; Leavesley, Silas J.

2018-02-01

Autofluorescence has historically been considered a nuisance in medical imaging. Many endogenous fluorophores, specifically, collagen, elastin, NADH, and FAD, are found throughout the human body. Diagnostically, these signals can be prohibitive since they can outcompete signals introduced for diagnostic purposes. Recent advances in hyperspectral imaging have allowed the acquisition of significantly more data in a shorter time period by scanning the excitation spectra of fluorophores. The reduced acquisition time and increased signal-to-noise ratio allow for separation of significantly more fluorophores than previously possible. Here, we propose to utilize excitation-scanning of autofluorescence to examine tissues and diagnose pathologies. Spectra of autofluorescent molecules were obtained using a custom inverted microscope (TE-2000, Nikon Instruments) with a Xe arc lamp and thin film tunable filter array (VersaChrome, Semrock, Inc.) Scans utilized excitation wavelengths from 360 nm to 550 nm in 5 nm increments. The resultant spectra were used to examine hyperspectral image stacks from various collaborative studies, including an atherosclerotic rat model and a colon cancer study. Hyperspectral images were analyzed with ENVI and custom Matlab scripts including linear spectral unmixing (LSU) and principal component analysis (PCA). Initial results suggest the ability to separate the signals of endogenous fluorophores and measure the relative concentrations of fluorophores among healthy and diseased states of similar tissues. These results suggest pathology-specific changes to endogenous fluorophores can be detected using excitationscanning hyperspectral imaging. Future work will expand the library of pure molecules and will examine more defined disease states.

In Vivo Two-Photon Fluorescence Kinetics of Primate Rods and Cones

PubMed Central

Sharma, Robin; Schwarz, Christina; Williams, David R.; Palczewska, Grazyna; Palczewski, Krzysztof; Hunter, Jennifer J.

2016-01-01

Purpose The retinoid cycle maintains vision by regenerating bleached visual pigment through metabolic events, the kinetics of which have been difficult to characterize in vivo. Two-photon fluorescence excitation has been used previously to track autofluorescence directly from retinoids and pyridines in the visual cycle in mouse and frog retinas, but the mechanisms of the retinoid cycle are not well understood in primates. Methods We developed a two-photon fluorescence adaptive optics scanning light ophthalmoscope dedicated to in vivo imaging in anesthetized macaques. Using pulsed light at 730 nm, two-photon fluorescence was captured from rods and cones during light and dark adaptation through the eye's pupil. Results The fluorescence from rods and cones increased with light exposure but at different rates. During dark adaptation, autofluorescence declined, with cone autofluorescence decreasing approximately 4 times faster than from rods. Rates of autofluorescence decrease in rods and cones were approximately 4 times faster than their respective rates of photopigment regeneration. Also, subsets of sparsely distributed cones were less fluorescent than their neighbors immediately following bleach at 565 nm and they were comparable with the S cone mosaic in density and distribution. Conclusions Although other molecules could be contributing, we posit that these fluorescence changes are mediated by products of the retinoid cycle. In vivo two-photon ophthalmoscopy provides a way to monitor noninvasively stages of the retinoid cycle that were previously inaccessible in the living primate eye. This can be used to assess objectively photoreceptor function in normal and diseased retinas. PMID:26903225

Biomarkers of chronic kidney disease in the urine of diabetic/hypertensive patients by means of Raman spectroscopy

NASA Astrophysics Data System (ADS)

Vieira, Elzo Everton de Sousa; Bispo, Jeyse Aliana Martis; Fernandes, Adriana Barrinha; Silveira, Landulfo

2016-03-01

Diabetes mellitus (DM) and arterial hypertension (AH) are common diseases that, if untreated, predispose the patient to renal failure. This study aimed to evaluate possible biomarkers in the urine of patients with DM and AH capable to predict the chronic renal disease, by means of Raman spectroscopy. Urines were obtained from patients with DM and AH, and separated into four groups: no symptoms of diseases related to DM and AH (G1), with low clinical complications (G2), with severe clinical complications (G3), and with chronic kidney disease (G4) arised from DM and AH. It has been used a dispersive Raman spectrometer (830nm, 250mW, 20s accumulation). In the spectra of urine it was identified Raman peaks at 680cm-1 (creatinine), 1004cm-1 (urea) and 1128cm-1 (glucose). The results revealed that G2, G3 and G4 presented the creatinine peak with lower intensity than G1 (p < 0.05). It was observed that G2, G3 and G4 showed lower intensity of the urea peak compared to G1 (p < 0.05) and G4 showed lower intensity compared to G2 and G3 (p < 0.05). Despite not significant, the glucose peak showed lower intensity in G1 when compared to the other groups. A model for classification of groups according to clinical criteria, using Sparse Multinomial Logistic Regression, taking as inputs the intensities of creatine, urea and glucose peaks allowed correct classification of 88.9% for G1, 36.8% for G2, 43.8% for G3 and 84.2% for G4. These results demonstrated the possibility of obtaining diagnostic information for complications of kidney disease associated to DM and AH, particularly the renal failure.

The safety and feasibility of extracorporeal high-intensity focused ultrasound (HIFU) for the treatment of liver and kidney tumours in a Western population

PubMed Central

Illing, R O; Kennedy, J E; Wu, F; ter Haar, G R; Protheroe, A S; Friend, P J; Gleeson, F V; Cranston, D W; Phillips, R R; Middleton, M R

2005-01-01

High-intensity focused ultrasound (HIFU) provides a potential noninvasive alternative to conventional therapies. We report our preliminary experience from clinical trials designed to evaluate the safety and feasibility of a novel, extracorporeal HIFU device for the treatment of liver and kidney tumours in a Western population. The extracorporeal, ultrasound-guided Model-JC Tumor Therapy System (HAIFU™ Technology Company, China) has been used to treat 30 patients according to four trial protocols. Patients with hepatic or renal tumours underwent a single therapeutic HIFU session under general anaesthesia. Magnetic resonance imaging 12 days after treatment provided assessment of response. The patients were subdivided into those followed up with further imaging alone or those undergoing surgical resection of their tumours, which enabled both radiological and histological assessment. HIFU exposure resulted in discrete zones of ablation in 25 of 27 evaluable patients (93%). Ablation of liver tumours was achieved more consistently than for kidney tumours (100 vs 67%, assessed radiologically). The adverse event profile was favourable when compared to more invasive techniques. HIFU treatment of liver and kidney tumours in a Western population is both safe and feasible. These findings have significant implications for future noninvasive image-guided tumour ablation. PMID:16189519

Fluorescence lifetime as a new parameter in analytical cytology measurements

NASA Astrophysics Data System (ADS)

Steinkamp, John A.; Deka, Chiranjit; Lehnert, Bruce E.; Crissman, Harry A.

1996-05-01

A phase-sensitive flow cytometer has been developed to quantify fluorescence decay lifetimes on fluorochrome-labeled cells/particles. This instrument combines flow cytometry (FCM) and frequency-domain fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved lifetime measurements, while preserving conventional FCM capabilities. Cells are analyzed as they intersect a high-frequency, intensity-modulated (sine wave) laser excitation beam. Fluorescence signals are processed by conventional and phase-sensitive signal detection electronics and displayed as frequency distribution histograms. In this study we describe results of fluorescence intensity and lifetime measurements on fluorescently labeled particles, cells, and chromosomes. Examples of measurements on intrinsic cellular autofluorescence, cells labeled with immunofluorescence markers for cell- surface antigens, mitochondria stains, and on cellular DNA and protein binding fluorochromes will be presented to illustrate unique differences in measured lifetimes and changes caused by fluorescence quenching. This innovative technology will be used to probe fluorochrome/molecular interactions in the microenvironment of cells/chromosomes as a new parameter and thus expand the researchers' understanding of biochemical processes and structural features at the cellular and molecular level.

Spatially resolved bimodal spectroscopy for classification/evaluation of mouse skin inflammatory and pre-cancerous stages

NASA Astrophysics Data System (ADS)

Díaz-Ayil, Gilberto; Amouroux, Marine; Clanché, Fabien; Granjon, Yves; Blondel, Walter C. P. M.

2009-07-01

Spatially-resolved bimodal spectroscopy (multiple AutoFluorescence AF excitation and Diffuse Reflectance DR), was used in vivo to discriminate various healthy and precancerous skin stages in a pre-clinical model (UV-irradiated mouse): Compensatory Hyperplasia CH, Atypical Hyperplasia AH and Dysplasia D. A specific data preprocessing scheme was applied to intensity spectra (filtering, spectral correction and intensity normalization), and several sets of spectral characteristics were automatically extracted and selected based on their discrimination power, statistically tested for every pair-wise comparison of histological classes. Data reduction with Principal Components Analysis (PCA) was performed and 3 classification methods were implemented (k-NN, LDA and SVM), in order to compare diagnostic performance of each method. Diagnostic performance was studied and assessed in terms of Sensibility (Se) and Specificity (Sp) as a function of the selected features, of the combinations of 3 different inter-fibres distances and of the numbers of principal components, such that: Se and Sp ~ 100% when discriminating CH vs. others; Sp ~ 100% and Se > 95% when discriminating Healthy vs. AH or D; Sp ~ 74% and Se ~ 63% for AH vs. D.

Iterative Correction Scheme Based on Discrete Cosine Transform and L1 Regularization for Fluorescence Molecular Tomography With Background Fluorescence.

PubMed

Zhang, Jiulou; Shi, Junwei; Guang, Huizhi; Zuo, Simin; Liu, Fei; Bai, Jing; Luo, Jianwen

2016-06-01

High-intensity background fluorescence is generally encountered in fluorescence molecular tomography (FMT), because of the accumulation of fluorescent probes in nontarget tissues or the existence of autofluorescence in biological tissues. The reconstruction results are affected or even distorted by the background fluorescence, especially when the distribution of fluorescent targets is relatively sparse. The purpose of this paper is to reduce the negative effect of background fluorescence on FMT reconstruction. After each iteration of the Tikhonov regularization algorithm, 3-D discrete cosine transform is adopted to filter the intermediate results. And then, a sparsity constraint step based on L1 regularization is applied to restrain the energy of the objective function. Phantom experiments with different fluorescence intensities of homogeneous and heterogeneous background are carried out to validate the performance of the proposed scheme. The results show that the reconstruction quality can be improved with the proposed iterative correction scheme. The influence of background fluorescence in FMT can be reduced effectively because of the filtering of the intermediate results, the detail preservation, and noise suppression of L1 regularization.

Increasing access to kidney transplantation in countries with limited resources: the Indian experience with kidney paired donation.

PubMed

Kute, Vivek B; Vanikar, Aruna V; Shah, Pankaj R; Gumber, Manoj R; Patel, Himanshu V; Engineer, Divyesh P; Modi, Pranjal R; Shah, Veena R; Trivedi, Hargovind L

2014-10-01

According to the Indian chronic kidney disease registry, in 2010 only 2% of end stage kidney disease patients were managed with kidney transplantation, 37% were managed with dialysis and 61% were treated conservatively without renal replacement therapy. In countries like India, where a well-organized deceased donor kidney transplantation program is not available, living donor kidney transplantation is the major source of organs for kidney transplantation. The most common reason to decline a donor for directed living donation is ABO incompatibility, which eliminates up to one third of the potential living donor pool. Because access to transplantation with human leukocyte antigen (HLA)-desensitization protocols and ABO incompatible transplantation is very limited due to high costs and increased risk of infections from more intense immunosuppression, kidney paired donation (KPD) promises hope to a growing number of end stage kidney disease patients. KPD is a rapidly growing and cost-effective living donor kidney transplantation strategy for patients who are incompatible with their healthy, willing living donor. In principle, KPD is feasible for any centre that performs living donor kidney transplantation. In transplant centres with a large living donor kidney transplantation program KPD does not require extra infrastructure, decreases waiting time, avoids transplant tourism and prevents commercial trafficking. Although KPD is still underutilized in India, it has been performed more frequently in recent times. To substantially increase donor pool and transplant rates, transplant centres should work together towards a national KPD program and frame a uniform acceptable allocation policy. © 2014 Asian Pacific Society of Nephrology.

Advanced glycation end-products (AGEs) accumulation in skin: relations with chronic kidney disease-mineral and bone disorder.

PubMed

França, Renata de Almeida; Esteves, André de Barros Albuquerque; Borges, Cynthia de Moura; Quadros, Kélcia Rosana da Silva; Falcão, Luiz Carlos Nogueira; Caramori, Jacqueline Costa Teixeira; Oliveira, Rodrigo Bueno de

2017-01-01

Chronic kidney disease (CKD) is associated with high morbidity and mortality rates, main causes related with cardiovascular disease (CVD) and bone mineral disorder (CKD-BMD). Uremic toxins, as advanced glycation end products (AGEs), are non-traditional cardiovascular risk factor and play a role on development of CKD-BMD in CKD. The measurement of skin autofluorescence (sAF) is a noninvasive method to assess the level of AGEs in tissue, validated in CKD patients. The aim of this study is analyze AGEs measured by sAF levels (AGEs-sAF) and its relations with CVD and BMD parameters in HD patients. Twenty prevalent HD patients (HD group) and healthy subjects (Control group, n = 24), performed biochemical tests and measurements of anthropometric parameters and AGEs-sAF. In addition, HD group performed measurement of intact parathormone (iPTH), transthoracic echocardiogram and radiographies of pelvis and hands for vascular calcification score. AGEs-sAF levels are elevated both in HD and control subjects ranged according to the age, although higher at HD than control group. Single high-flux HD session does not affect AGEs-sAF levels. AGEs-sAF levels were not related to ventricular mass, interventricular septum or vascular calcification in HD group. AGEs-sAF levels were negatively associated with serum iPTH levels. Our study detected a negative correlation of AGEs-sAF with serum iPTH, suggesting a role of AGEs on the pathophysiology of bone disease in HD prevalent patients. The nature of this relation and the clinical application of this non-invasive methodology for evaluation AGEs deposition must be confirmed and clarified in future studies.

A successful treatment of life-threatening bleeding from polycystic kidneys with antifibrinolytic agent tranexamic acid.

PubMed

Vujkovac, Bojan; Sabovic, Miso

2006-10-01

We describe a successful treatment of a severe, persistent bleeding from both kidneys in a patient with autosomal dominant polycystic kidney disease (ADPKD) with tranexamic acid (TXA), a potent antifibrinolytic agent. The bleeding could not be controlled by intensive conservative treatment, it became life-threatening and urgent bilateral nephrectomy was intended. Since local and systemic hyperfibrinolysis play a role in bleeding in ADPKD patients, we tried TXA treatment. In fact, the massive bleeding promptly stopped, and haematuria gradually ceased. Removal of both kidneys was prevented. After 5 days both ureters became obstructed by blood clots, but placing J-catheters in each pyelon successfully solved this complication. Our case shows that it is reasonable to try antifibrinolytic treatment with TXA in such devastating uncontrolled bleeding.

Association of Intensive Blood Pressure Control and Kidney Disease Progression in Nondiabetic Patients With Chronic Kidney Disease

PubMed Central

Tsai, Wan-Chuan; Peng, Yu-Sen; Yang, Ju-Yeh; Chen, Hung-Yuan; Chiu, Yen-Ling; Hsu, Shih-Ping; Ko, Mei-Ju; Pai, Mei-Fen; Tu, Yu-Kang; Hung, Kuan-Yu; Chien, Kuo-Liong

2017-01-01

Importance The optimal blood pressure (BP) target remains debated in nondiabetic patients with chronic kidney disease (CKD). Objective To compare intensive BP control (<130/80 mm Hg) with standard BP control (<140/90 mm Hg) on major renal outcomes in patients with CKD without diabetes. Data Sources Searches of PubMed, MEDLINE, Embase, and Cochrane Library for publications up to March 24, 2016. Study Selection Randomized clinical trials that compared an intensive vs a standard BP target in nondiabetic adults with CKD, reporting changes in glomerular filtration rate (GFR), doubling of serum creatinine level, 50% reduction in GFR, end-stage renal disease (ESRD), or all-cause mortality. Data Extraction and Synthesis Random-effects meta-analyses for pooling effect measures. Meta-regression and subgroup analyses for exploring heterogeneity. Main Outcomes and Measures Differences in annual rate of change in GFR were expressed as mean differences with 95% CIs. Differences in doubling of serum creatinine or 50% reduction in GFR, ESRD, composite renal outcome, and all-cause mortality were expressed as risk ratios (RRs) with 95% CIs. Results We identified 9 trials with 8127 patients and a median follow-up of 3.3 years. Compared with standard BP control, intensive BP control did not show a significant difference on the annual rate of change in GFR (mean difference, 0.07; 95% CI, −0.16 to 0.29 mL/min/1.73 m2/y), doubling of serum creatinine level or 50% reduction in GFR (RR, 0.99; 95% CI, 0.76-1.29), ESRD (RR, 0.96; 95% CI, 0.78-1.18), composite renal outcome (RR, 0.99; 95% CI, 0.81-1.21), or all-cause mortality (RR, 0.81; 95% CI, 0.64-1.02). Intensive BP control reduced mortality (RR, 0.78; 95% CI, 0.61-0.99) in sensitivity analysis when the study populations were strictly restricted to those without diabetes. Nonblacks and patients with higher levels of proteinuria showed a trend of lower risk of kidney disease progression with intensive BP control. Conclusions and Relevance Targeting BP below the current standard did not provide additional benefit for renal outcomes compared with standard treatment during a follow-up of 3.3 years in patients with CKD without diabetes. However, nonblack patients or those with higher levels of proteinuria might benefit from the intensive BP-lowering treatments. PMID:28288249

A Randomized Controlled Trial of an Intensive Nutrition Intervention Versus Standard Nutrition Care to Avoid Excess Weight Gain After Kidney Transplantation: The INTENT Trial.

PubMed

Henggeler, Cordula K; Plank, Lindsay D; Ryan, Kristin J; Gilchrist, Emily L; Casas, Jessie M; Lloyd, Lyn E; Mash, Laura E; McLellan, Sandra L; Robb, Jennifer M; Collins, Michael G

2018-05-02

Excessive weight gain is common after kidney transplantation and increases cardiovascular risk. The aim of this randomized controlled trial was to determine whether an intensive nutrition and exercise intervention delivered alongside routine post-transplant care would reduce post-transplant weight gain. Single-blind, randomized controlled trial. Adult kidney transplant recipients at a regional transplant center were recruited during routine outpatient clinic visits in the first month after transplant. Patients with a body mass index >40 kg/m 2 or <18.5 kg/m 2 , severe malnutrition, or ongoing medical complications were excluded. Participants were randomized to intensive nutrition intervention (individualized nutrition and exercise counselling; 12 dietitian visits; 3 exercise physiologist visits over 12 months) or to standard nutrition care (guideline based; 4 dietitian visits). The primary outcome was weight at 6 months after transplant adjusted for baseline weight, obesity, and gender, analyzed using analysis of covariance. The secondary outcomes included body composition, biochemistry, quality of life, and physical function. Thirty-seven participants were randomized to the intensive intervention (n = 19) or to standard care (n = 18); one intensive group participant withdrew before baseline. Weight increased between baseline, 6 and 12 months (78.0 ± 13.7 [standard deviation], 79.6 ± 13.0 kg, 81.6 ± 12.9 kg; mean change 4.6% P < .001) but at 6 months did not differ significantly between the groups: 77.0 ± 12.4 kg (intensive); 82.2 ± 13.4 kg (standard); difference in adjusted means 0.4 kg (95% confidence interval: -2.2 to 3.0 kg); analysis of covariance P = .7. No between-group differences in secondary outcomes were observed. Across the whole cohort, total body protein and physical function (gait speed, sit to stand, grip strength, physical activity, and quality of life [all but 2 domains]) improved. However, adverse changes were seen for total body fat, HbA1c, and fasting glucose across the cohort. Kidney transplant recipients in the first year after transplant did not benefit from an intensive nutrition intervention compared with standard nutrition care, although weight gain was relatively modest in both groups. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

LRRK2 knockout mice have an intact dopaminergic system but display alterations in exploratory and motor co-ordination behaviors

PubMed Central

2012-01-01

Mutations in the LRRK2 gene are the most common cause of genetic Parkinson’s disease. Although the mechanisms behind the pathogenic effects of LRRK2 mutations are still not clear, data emerging from in vitro and in vivo models suggests roles in regulating neuronal polarity, neurotransmission, membrane and cytoskeletal dynamics and protein degradation. We created mice lacking exon 41 that encodes the activation hinge of the kinase domain of LRRK2. We have performed a comprehensive analysis of these mice up to 20 months of age, including evaluation of dopamine storage, release, uptake and synthesis, behavioral testing, dendritic spine and proliferation/neurogenesis analysis. Our results show that the dopaminergic system was not functionally comprised in LRRK2 knockout mice. However, LRRK2 knockout mice displayed abnormal exploratory activity in the open-field test. Moreover, LRRK2 knockout mice stayed longer than their wild type littermates on the accelerated rod during rotarod testing. Finally, we confirm that loss of LRRK2 caused degeneration in the kidney, accompanied by a progressive enhancement of autophagic activity and accumulation of autofluorescent material, but without evidence of biphasic changes. PMID:22647713

Quantum dots as contrast agents for endoscopy: mathematical modeling and experimental validation of the optimal excitation wavelength

NASA Astrophysics Data System (ADS)

Roy, Mathieu; DaCosta, Ralph S.; Weersink, Robert; Netchev, George; Davidson, Sean R. H.; Chan, Warren; Wilson, Brian C.

2007-02-01

Our group is investigating the use of ZnS-capped CdSe quantum dot (QD) bioconjugates combined with fluorescence endoscopy for improved early cancer detection in the esophagus, colon and lung. A major challenge in using fluorescent contrast agents in vivo is to extract the relevant signal from the tissue autofluorescence (AF). Our studies are aimed at maximizing the QD signal to AF background ratio (SBR) to facilitate detection. This work quantitatively evaluates the effect of the excitation wavelength on the SBR, using both experimental measurements and mathematical modeling. Experimental SBR measurements were done by imaging QD solutions placed onto (surface) or embedded in (sub-surface) ex vivo murine tissue samples (brain, kidney, liver, lung), using a polymethylmethacrylate (PMMA) microchannel phantom. The results suggest that the maximum contrast is reached when the excitation wavelength is set at 400+/-20 μm for the surface configuration. For the sub-surface configuration, the optimal excitation wavelength varies with the tissue type and QD emission wavelengths. Our mathematical model, based on an approximation to the diffusion equation, successfully predicts the optimal excitation wavelength for the surface configuration, but needs further modifications to be accurate in the sub-surface configuration.

Role of autofluorescence in inflammatory/infective diseases of the retina and choroid.

PubMed

Samy, Ahmed; Lightman, Sue; Ismetova, Filis; Talat, Lazha; Tomkins-Netzer, Oren

2014-01-01

Fundus autofluorescence (FAF) has recently emerged as a novel noninvasive imaging technique that uses the fluorescent properties of innate fluorophores accumulated in the retinal pigment epithelium (RPE) to assess the health and viability of the RPE/photoreceptor complex. Recent case reports suggest FAF as a promising tool for monitoring eyes with posterior uveitis helping to predict final visual outcome. In this paper we review the published literature on FAF in these disorders, specifically patterns in infectious and noninfectious uveitis, and illustrate some of these with short case histories.

A fast, robust pattern recognition asystem for low light level image registration and its application to retinal imaging

NASA Astrophysics Data System (ADS)

Wade, Alex Robert; Fitzke, Frederick W.

1998-08-01

We describe an image processing system which we have developed to align autofluorescence and high-magnification images taken with a laser scanning ophthalmoscope. The low signal to noise ratio of these images makes pattern recognition a non-trivial task. However, once n images are aligned and averaged, the noise levels drop by a factor of n and the image quality is improved. We include examples of autofluorescence images and images of the cone photoreceptor mosaic obtained using this system.

Multimodal autofluorescence detection of cancer: from single cells to living organism

NASA Astrophysics Data System (ADS)

Horilova, J.; Cunderlikova, B.; Cagalinec, M.; Chorvat, D.; Marcek Chorvatova, A.

2018-02-01

Multimodal optical imaging of suspected tissues is showing to be a promising method for distinguishing suspected cancerous tissues from healthy ones. In particular, the combination of steady-state spectroscopic methods with timeresolved fluorescence provides more precise insight into native metabolism when focused on tissue autofluorescence. Cancer is linked to specific metabolic remodelation detectable spectroscopically. In this work, we evaluate possibilities and limitations of multimodal optical cancer detection in single cells, collagen-based 3D cell cultures and in living organisms (whole mice), as a representation of gradually increasing complexity of model systems.

Radiotherapy for gastric lymphoma: a planning study of 3D conformal radiotherapy, the half-beam method, and intensity-modulated radiotherapy.

PubMed

Inaba, Koji; Okamoto, Hiroyuki; Wakita, Akihisa; Nakamura, Satoshi; Kobayashi, Kazuma; Harada, Ken; Kitaguchi, Mayuka; Sekii, Shuhei; Takahashi, Kana; Yoshio, Kotaro; Murakami, Naoya; Morota, Madoka; Ito, Yoshinori; Sumi, Minako; Uno, Takashi; Itami, Jun

2014-11-01

During radiotherapy for gastric lymphoma, it is difficult to protect the liver and kidneys in cases where there is considerable overlap between these organs and the target volume. This study was conducted to compare the three radiotherapy planning techniques of four-fields 3D conformal radiotherapy (3DCRT), half-field radiotherapy (the half-beam method) and intensity-modulated radiotherapy (IMRT) used to treat primary gastric lymphoma in which the planning target volume (PTV) had a large overlap with the left kidney. A total of 17 patients with gastric diffuse large B-cell lymphoma (DLBCL) were included. In DLBCL, immunochemotherapy (Rituximab + CHOP) was followed by radiotherapy of 40 Gy to the whole stomach and peri-gastric lymph nodes. 3DCRT, the half-field method, and IMRT were compared with respect to the dose-volume histogram (DVH) parameters and generalized equivalent uniform dose (gEUD) to the kidneys, liver and PTV. The mean dose and gEUD for 3DCRT was higher than for IMRT and the half-beam method in the left kidney and both kidneys. The mean dose and gEUD of the left kidney was 2117 cGy and 2224 cGy for 3DCRT, 1520 cGy and 1637 cGy for IMRT, and 1100 cGy and 1357 cGy for the half-beam method, respectively. The mean dose and gEUD of both kidneys was 1335 cGy and 1559 cGy for 3DCRT, 1184 cGy and 1311 cGy for IMRT, and 700 cGy and 937 cGy for the half-beam method, respectively. Dose-volume histograms (DVHs) of the liver revealed a larger volume was irradiated in the dose range <25 Gy with 3DCRT, while the half-beam method irradiated a larger volume of liver with the higher dose range (>25 Gy). IMRT and the half-beam method had the advantages of dose reduction for the kidneys and liver. © The Author 2014. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Endogenous Antiangiogenic Factors in Chronic Kidney Disease: Potential Biomarkers of Progression.

PubMed

Tanabe, Katsuyuki; Sato, Yasufumi; Wada, Jun

2018-06-24

Chronic kidney disease (CKD) is a major global health problem. Unless intensive intervention is initiated, some patients can rapidly progress to end-stage kidney disease. However, it is often difficult to predict renal outcomes using conventional laboratory tests in individuals with CKD. Therefore, many researchers have been searching for novel biomarkers to predict the progression of CKD. Angiogenesis is involved in physiological and pathological processes in the kidney and is regulated by the balance between a proangiogenic factor, vascular endothelial growth factor (VEGF)-A, and various endogenous antiangiogenic factors. In recent reports using genetically engineered mice, the roles of these antiangiogenic factors in the pathogenesis of kidney disease have become increasingly clear. In addition, recent clinical studies have demonstrated associations between circulating levels of antiangiogenic factors and renal dysfunction in CKD patients. In this review, we summarize recent advances in the study of representative endogenous antiangiogenic factors, including soluble fms-related tyrosine kinase 1, soluble endoglin, pigment epithelium-derived factor, VEGF-A 165 b, endostatin, and vasohibin-1, in associations with kidney diseases and discuss their predictive potentials as biomarkers of progression of CKD.

[Strategies for prevention of acute kidney injury in cardiac surgery: an integrative review].

PubMed

Santana-Santos, Eduesley; Marcusso, Marila Eduara Fátima; Rodrigues, Amanda Oliveira; Queiroz, Fernanda Gomes de; Oliveira, Larissa Bertacchini de; Rodrigues, Adriano Rogério Baldacin; Palomo, Jurema da Silva Herbas

2014-01-01

Acute kidney injury is a common complication after cardiac surgery and is associated with increased morbidity and mortality and increased length of stay in the intensive care unit. Considering the high prevalence of acute kidney injury and its association with worsened prognosis, the development of strategies for renal protection in hospitals is essential to reduce the associated high morbidity and mortality, especially for patients at high risk of developing acute kidney injury, such as patients who undergo cardiac surgery. This integrative review sought to assess the evidence available in the literature regarding the most effective interventions for the prevention of acute kidney injury in patients undergoing cardiac surgery. To select the articles, we used the CINAHL and MedLine databases. The sample of this review consisted of 16 articles. After analyzing the articles included in the review, the results of the studies showed that only hydration with saline has noteworthy results in the prevention of acute kidney injury. The other strategies are controversial and require further research to prove their effectiveness.

The surgical management of upper tract stone disease among spinal cord-injured patients.

PubMed

Welk, B; Shariff, S; Ordon, M; Catharine Craven, B; Herschorn, S; Garg, A X

2013-06-01

Retrospective cohort study, using linked, population-based health-care data. To describe the incidence, management and outcomes of surgically treated kidney stones after spinal cord injury (SCI). To evaluate the impact of a past history of kidney stones on the occurrence of kidney stones. Ontario, Canada. A total of 5121 patients were followed a median of 4 years after an incident SCI (occurring between 2002 and 2011). The primary outcome was surgical intervention for upper tract kidney stones. In follow-up, 66 patients (1.3%) had 89 episodes of surgically treated kidney stones. Treatments included: ureteroscopic lithotripsy (34%), ureteral stent/percutaneous nephrostomy (30%), shockwave lithotripsy (19%) or percutaneous nephrolithotripsy (17%). Following stone treatment, the 30-day mortality rate was low, and the 30-day admission rate to an intensive care unit was 12%. A history of surgically treated kidney stones before SCI (compared with no such history) was associated with a higher risk of kidney stones after SCI (27 vs 3 per 1000 person-years; adjusted hazard ratio 14.74, 95% confidence interval 5.69-38.22). During intermediate follow-up after SCI, surgically treated upper tract kidney stones occur in 1.3% of patients. Ureteroscopy with lithotripsy is the most common treatment. A history of surgically managed kidney stones before SCI portends a higher risk of stones after SCI.

Acute kidney injury in the ICU: from injury to recovery: reports from the 5th Paris International Conference.

PubMed

Bellomo, Rinaldo; Ronco, Claudio; Mehta, Ravindra L; Asfar, Pierre; Boisramé-Helms, Julie; Darmon, Michael; Diehl, Jean-Luc; Duranteau, Jacques; Hoste, Eric A J; Olivier, Joannes-Boyau; Legrand, Matthieu; Lerolle, Nicolas; Malbrain, Manu L N G; Mårtensson, Johan; Oudemans-van Straaten, Heleen M; Parienti, Jean-Jacques; Payen, Didier; Perinel, Sophie; Peters, Esther; Pickkers, Peter; Rondeau, Eric; Schetz, Miet; Vinsonneau, Christophe; Wendon, Julia; Zhang, Ling; Laterre, Pierre-François

2017-12-01

The French Intensive Care Society organized its yearly Paris International Conference in intensive care on June 18-19, 2015. The main purpose of this meeting is to gather the best experts in the field in order to provide the highest quality update on a chosen topic. In 2015, the selected theme was: "Acute Renal Failure in the ICU: from injury to recovery." The conference program covered multiple aspects of renal failure, including epidemiology, diagnosis, treatment and kidney support system, prognosis and recovery together with acute renal failure in specific settings. The present report provides a summary of every presentation including the key message and references and is structured in eight sections: (a) diagnosis and evaluation, (b) old and new diagnosis tools, (c) old and new treatments, (d) renal replacement therapy and management, (e) acute renal failure witness of other conditions, (f) prognosis and recovery, (g) extracorporeal epuration beyond the kidney, (h) the use of biomarkers in clinical practice http://www.srlf.org/5th-paris-international-conference-jeudi-18-et-vendredi-19-juin-2015/ .

In vivo optical imaging of amblyopia: Digital subtraction autofluorescence and split-spectrum amplitude-decorrelation angiography.

PubMed

Guo, Lei; Tao, Jun; Xia, Fan; Yang, Zhi; Ma, Xiaoli; Hua, Rui

2016-09-01

Amblyopia is a visual impairment that is attributed to either abnormal binocular interactions or visual deprivation. The retina and choroids have been shown to be involved in the development of amblyopia. The purpose of this study was to investigate the retinal and choroidal microstructural abnormalities of amblyopia using digital subtraction autofluorescence and split-spectrum amplitude-decorrelation angiography (SSADA) approaches. This prospective study included 44 eyes of 22 patients with unilateral amblyopia. All patients who received indirect ophthalmoscopy, combined depth imaging spectral domain optical coherence tomography (OCT), SSADA-OCT, and macular blue light (BL-) and near-infrared (NIR-) autofluorescences underwent pupil dilation. The subfoveal choroidal thickness (SFCT) was measured. BL- and NIR-autofluorescences were determined for all patients and used to generate subtraction images with ImageJ software. The superficial, deep layers of the retina, and inner choroid layer were required for SSADA-OCT. For the normal eyes, a regularly increasing signal was observed in the central macula based on the subtraction images. In contrast, a decreased signal for the central patch or a reduced peak was detected in 16 of 22 amblyopic eyes (72.7%). The mean SFCT of the amblyopic eyes was greater than that of the fellow normal eyes (399.25 ± 4.944 µm vs. 280.58 ± 6.491 µm, respectively, P < 0.05). SSADA-OCT revealed a normal choroidal capillary network in all fellow normal eyes. However, 18 of 22 amblyopic eyes (86.4%) exhibited a blurry choroidal capillary network, and 15 of 22 amblyopic eyes (68.2%) displayed a dark atrophic patch. This is the first report of amblyopia using SSADA-OCT and digital subtraction images of autofluorescence. The mechanistic relationship of a thicker choroid and choroidal capillary atrophy with amblyopia remains to be described. The digital subtraction image confirmed the changes in the microstructure of the amblyopic retina as a supplementary approach to detect the progression of amblyopia. Lasers Surg. Med. 48:660-667, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Ocular fundus auto-fluorescence observations at different wavelengths in patients with age-related macular degeneration and diabetic retinopathy.

PubMed

Hammer, Martin; Königsdörffer, Ekkehart; Liebermann, Christiane; Framme, Carsten; Schuch, Günter; Schweitzer, Dietrich; Strobel, Jürgen

2008-01-01

Post-translational protein modification by lipid peroxidation products or glycation is a feature of aging as well as pathologic processes in postmitotic cells at the ocular fundus exposed to an oxidative environment. The accumulation of modified proteins such as those found in lipofuscin and advanced glycation end products (AGEs) contribute greatly to the fundus auto-fluorescence. The distinct fluorescence spectra of lipofuscin and AGE enable their differentiation in multispectral fundus fluorescence imaging. A dual-centre consecutive case series of 78 pseudo-phacic patients is reported. Digital colour fundus photographs as well as auto-fluorescence images were taken from 33 patients with age related macular degeneration (AMD), 13 patients with diabetic retinopathy (RD), or from 32 cases without pathologic findings (controls). Fluorescence was excited at 475-515 nm or 476-604 nm and recorded in the emission bands 530-675 nm or 675-715 nm, respectively. Fluorescence images excited at 475-515 nm were taken by a colour CCD-camera (colour-fluorescence imaging) enabling the separate recording of green and red fluorescence. The ratio of green versus red fluorescence was calculated within a representative region of each image. The 530-675 nm auto-fluorescence in AMD patients was dominated by the red emission (green vs. red ratio, g/r = 0.861). In comparison, the fluorescence of the diabetics was green-shifted (g/r = 0.946; controls: g/r = 0.869). Atrophic areas (geographic atrophy, laser scars) showed massive hypo-fluorescence in both emission bands. Hyper-fluorescent drusen and exudates, unobtrusive in the colour fundus images as well as in the fluorescence images with emission >667 nm, showed an impressive green-shift in the colour-fluorescence image. Lipofuscin is the dominant fluorophore at long wavelengths (>675 nm or red channel of the colour fluorescence image). In the green spectral region, we found an additional emission of collagen and elastin (optic disc, sclera) as well as deposits in drusen and exudates. The green shift of the auto-fluorescence in RD may be a hint of increased AGE concentrations.

Conjunctival UV autofluorescence--prevalence and risk factors.

PubMed

Wolffsohn, James S; Drew, Tom; Sulley, Anna

2014-12-01

Autofluorescence of ultraviolet (UV) light has been shown to occur in localised areas of the bulbar conjunctiva, which map to active cellular changes due to UV and environmental exposure. This study examined the presence of conjunctival UV autofluorescence in eye care practitioners (ECPs) across Europe and the Middle East and its associated risk factors. Images were captured of 307 ECPs right eyes in the Czech Republic, Germany, Greece, Kuwait, Netherlands, Sweden, Switzerland, United Arab Emirates and the United Kingdom using a Nikon D100 camera and dual flash units through UV filters. UV autofluorescence was outlined using ImageJ software and the nasal and temporal area quantified. Subjects were required to complete a questionnaire on their demographics and lifestyle including general exposure to UV and refractive correction. Average age of the subjects was 38.5±12.2 years (range 19-68) and 39.7% were male. Sixty-two percent of eyes had some conjunctival damage as indicated by UV autofluorescence. The average area of damage was higher (p=0.005) nasally (2.95±4.52mm(2)) than temporally (2.19±4.17mm(2)). The area of UV damage was not related to age (r=0.03, p=0.674), gender (p=0.194), self-reported sun exposure lifestyle (p>0.05), geographical location (p=0174), sunglasses use (p>0.05) or UV-blocking contact lens use (p>0.05), although it was higher in those wearing contact lenses with minimal UV-blocking and no spectacles (p=0.015). The area of UV damage was also less nasally in those who wore contact lenses and spectacles compared to those with no refractive correction use (p=0.011 nasal; p=0.958 temporal). UV conjunctival damage is common even in Europe, Kuwait and UAE, and among ECPs. The area of damage appears to be linked with the use of refractive correction, with greater damage nasally than temporally which may be explained by the peripheral light focusing effect. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Clinical Features of Kidney Transplant Recipients Admitted to the Intensive Care Unit.

PubMed

Freitas, Flávio Geraldo Rezende; Lombardi, Fábio; Pacheco, Eduardo Souza; Sandes-Freitas, Tainá Veras de; Viana, Laila Almeida; Junior, Hélio Tedesco-Silva; Medina-Pestana, José Osmar; Bafi, Antônio Tonete; Machado, Flavia Ribeiro

2018-03-01

There is a paucity of data regarding the complications in kidney transplant patients who may require intensive care unit (ICU) management, despite being the most common solid organ transplant worldwide. To identify the main reasons for ICU admission and to determine the factors associated with hospital mortality in kidney transplant recipients. This single-center retrospective cohort study was conducted between September 2013 and June 2014, including all consecutive kidney transplant patients requiring ICU admission. We collected data on patient demographics, transplant characteristics, clinical data, and prognostic scores. The independent determinants of hospital mortality were identified by multiple logistic regression analysis. We also assessed the performance of Simplified Acute Physiology Score 3 (SAPS 3) and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores. We analyzed data from 413 patients, the majority of whom were admitted late after renal transplantation (1169 days; 63-3003 days). The main reason for admission was sepsis (33.2%), followed by cardiovascular disease (16%). Age (odds ratio [OR] 1.05, confidence interval [CI], 1.01-1.09), SAPS 3 score (OR 1.04, CI, 1.01-1.08), the need for mechanical ventilation (OR 26.47, CI, 10.30-68.08), and vasopressor use (OR 3.34, CI, 1.37-8.13) were independently associated with hospital mortality. The performance of SAPS 3 and APACHE II scores was poor in this population and overestimated the mortality rates. Sepsis was the main reason for ICU admission in kidney transplant recipients, followed by cardiovascular disease. Age and disease severity were associated with hospital mortality.

Determination of minor and trace elements in kidney stones by x-ray fluorescence analysis

NASA Astrophysics Data System (ADS)

Srivastava, Anjali; Heisinger, Brianne J.; Sinha, Vaibhav; Lee, Hyong-Koo; Liu, Xin; Qu, Mingliang; Duan, Xinhui; Leng, Shuai; McCollough, Cynthia H.

2014-03-01

The determination of accurate material composition of a kidney stone is crucial for understanding the formation of the kidney stone as well as for preventive therapeutic strategies. Radiations probing instrumental activation analysis techniques are excellent tools for identification of involved materials present in the kidney stone. In particular, x-ray fluorescence (XRF) can be very useful for the determination of minor and trace materials in the kidney stone. The X-ray fluorescence measurements were performed at the Radiation Measurements and Spectroscopy Laboratory (RMSL) of department of nuclear engineering of Missouri University of Science and Technology and different kidney stones were acquired from the Mayo Clinic, Rochester, Minnesota. Presently, experimental studies in conjunction with analytical techniques were used to determine the exact composition of the kidney stone. A new type of experimental set-up was developed and utilized for XRF analysis of the kidney stone. The correlation of applied radiation source intensity, emission of X-ray spectrum from involving elements and absorption coefficient characteristics were analyzed. To verify the experimental results with analytical calculation, several sets of kidney stones were analyzed using XRF technique. The elements which were identified from this techniques are Silver (Ag), Arsenic (As), Bromine (Br), Chromium (Cr), Copper (Cu), Gallium (Ga), Germanium (Ge), Molybdenum (Mo), Niobium (Nb), Rubidium (Rb), Selenium (Se), Strontium (Sr), Yttrium (Y), Zirconium (Zr). This paper presents a new approach for exact detection of accurate material composition of kidney stone materials using XRF instrumental activation analysis technique.

Centrarchid fish as paratenic hosts of the giant kidney worm, Dioctophyma renale (Goeze, 1782), in Ontario, Canada.

PubMed

Measures, L N; Anderson, R C

1985-01-01

Infective larvae of Dioctophyma renale were found in the hypaxial musculature of pumpkinseed (Lepomis gibbosus L.) from three lakes in Algonquin Provincial Park, Ontario, Canada. This represents the first report of D. renale in centrarchid fish. In the three lakes surveyed prevalence and mean intensity ranged from 5 to 23% and one to two larvae respectively. Larvae elicited a mild granulomatous reaction in pumpkinseed. Two ferrets were each given five larvae from pumpkinseed. Adult D. renale were recovered from the right kidney capsule of ferrets 108 and 134 days post-infection. An opening in the ventral surface of the right kidney capsule was present in one ferret. Chronic peritonitis was associated with eggs of D. renale and cellular debris which probably entered the abdominal cavity from the right kidney capsule.

Two-Photon Autofluorescence Imaging Reveals Cellular Structures Throughout the Retina of the Living Primate Eye

PubMed Central

Sharma, Robin; Williams, David R.; Palczewska, Grazyna; Palczewski, Krzysztof; Hunter, Jennifer J.

2016-01-01

Purpose Although extrinsic fluorophores can be introduced to label specific cell types in the retina, endogenous fluorophores, such as NAD(P)H, FAD, collagen, and others, are present in all retinal layers. These molecules are a potential source of optical contrast and can enable noninvasive visualization of all cellular layers. We used a two-photon fluorescence adaptive optics scanning light ophthalmoscope (TPF-AOSLO) to explore the native autofluorescence of various cell classes spanning several layers in the unlabeled retina of a living primate eye. Methods Three macaques were imaged on separate occasions using a custom TPF-AOSLO. Two-photon fluorescence was evoked by pulsed light at 730 and 920 nm excitation wavelengths, while fluorescence emission was collected in the visible range from several retinal layers and different locations. Backscattered light was recorded simultaneously in confocal modality and images were postprocessed to remove eye motion. Results All retinal layers yielded two-photon signals and the heterogeneous distribution of fluorophores provided optical contrast. Several structural features were observed, such as autofluorescence from vessel walls, Müller cell processes in the nerve fibers, mosaics of cells in the ganglion cell and other nuclear layers of the inner retina, as well as photoreceptor and RPE layers in the outer retina. Conclusions This in vivo survey of two-photon autofluorescence throughout the primate retina demonstrates a wider variety of structural detail in the living eye than is available through conventional imaging methods, and broadens the use of two-photon imaging of normal and diseased eyes. PMID:26903224

Retinal pigment epithelial changes in chronic Vogt-Koyanagi-Harada disease: fundus autofluorescence and spectral domain-optical coherence tomography findings.

PubMed

Vasconcelos-Santos, Daniel V; Sohn, Elliott H; Sadda, Srinivas; Rao, Narsing A

2010-01-01

The purpose of this study was to determine whether fundus autofluorescence (FAF) and spectral domain-optical coherence tomography (SD-OCT) imaging allow better assessment of retinal pigment epithelium and the outer retina in subjects with chronic Vogt-Koyanagi-Harada disease compared with examination and angiography alone. A cross-sectional analysis of a series of seven consecutive patients with chronic Vogt-Koyanagi-Harada disease undergoing FAF and SD-OCT was conducted. Chronic disease was defined as duration of intraocular inflammation >3 months. Color fundus photographs were correlated to FAF and SD-OCT images. The images were later correlated to fluorescein angiography and indocyanine green angiography. All patients had sunset glow fundus, which resulted in no apparent corresponding abnormality on FAF or SD-OCT. Lesions with decreased autofluorescence signal were observed in 11 eyes (85%), being associated with loss of the retinal pigment epithelium and involvement of the outer retina on SD-OCT. In 5 eyes (38%), some of these lesions were very subtle on clinical examination but easily detected by FAF. Lesions with increased autofluorescence signal were seen in 8 eyes (61.5%), showing variable involvement of the outer retina on SD-OCT and corresponding clinically to areas of retinal pigment epithelium proliferation and cystoid macular edema. Combined use of FAF and SD-OCT imaging allowed noninvasive delineation of retinal pigment epithelium/outer retina changes in patients with chronic Vogt-Koyanagi-Harada disease, which were consistent with previous histopathologic reports. Some of these changes were not apparent on clinical examination.

LED induced autofluorescence (LIAF) imager with eight multi-filters for oral cancer diagnosis

NASA Astrophysics Data System (ADS)

Huang, Ting-Wei; Cheng, Nai-Lun; Tsai, Ming-Hsui; Chiou, Jin-Chern; Mang, Ou-Yang

2016-03-01

Oral cancer is one of the serious and growing problem in many developing and developed countries. The simple oral visual screening by clinician can reduce 37,000 oral cancer deaths annually worldwide. However, the conventional oral examination with the visual inspection and the palpation of oral lesions is not an objective and reliable approach for oral cancer diagnosis, and it may cause the delayed hospital treatment for the patients of oral cancer or leads to the oral cancer out of control in the late stage. Therefore, a device for oral cancer detection are developed for early diagnosis and treatment. A portable LED Induced autofluorescence (LIAF) imager is developed by our group. It contained the multiple wavelength of LED excitation light and the rotary filter ring of eight channels to capture ex-vivo oral tissue autofluorescence images. The advantages of LIAF imager compared to other devices for oral cancer diagnosis are that LIAF imager has a probe of L shape for fixing the object distance, protecting the effect of ambient light, and observing the blind spot in the deep port between the gumsgingiva and the lining of the mouth. Besides, the multiple excitation of LED light source can induce multiple autofluorescence, and LIAF imager with the rotary filter ring of eight channels can detect the spectral images of multiple narrow bands. The prototype of a portable LIAF imager is applied in the clinical trials for some cases in Taiwan, and the images of the clinical trial with the specific excitation show the significant differences between normal tissue and oral tissue under these cases.

Fundus Autofluorescence Captured With a Nonmydriatic Retinal Camera in Vegetarians Versus Nonvegetarians.

PubMed

Kommana, Sumana S; Padgaonkar, Pooja; Mendez, Nicole; Wu, Lesley; Szirth, Bernard; Khouri, Albert S

2015-09-09

A baseline level of lipofuscin in the retinal pigment epithelium (RPE) is inevitable with age, but increased levels due to increased oxidative stress can result in deleterious vision loss at older ages. As earlier detection of differences in levels can lead to superior preventative management, we studied the relationship between lipofuscin accumulation and dietary lifestyle (vegetarian vs. nonvegetarian) in the younger, healthy South Asian population using retinal fundus autofluorescence (FAF) imaging. In this pilot study, we examined 37 healthy subjects (average age 23 years ± 1) all undergoing similar stress levels as medical students at Rutgers New Jersey Medical School. Levels of lipofuscin concentrations were imaged using a FAF retinal camera (Canon CX-1). Two images (color and FAF) were captured of the left eye and included in the analysis. FAF quantitative scoring was measured in 2 regions of the captured image, the papillo-macular region (P) and the macula (M), by determining the grayscale score of a 35.5 mm(2) rectangle in the respective regions. Standardized scores (corrected to remove baseline fluorescence) were then obtained. Means, standard deviations, and t tests were performed for comparisons. Fundus autofluorescence scores of regions P and M were significantly different (P < .05) between groups. Region P was further standardized and results remained significant. Our preliminary results show that in this cohort, vegetarians had statistically significant lower levels of autofluorescence. These findings can have potential implications regarding long-term retinal health and risk for developing certain diseases over decades in subjects at risk for vision-threatening diseases. © 2015 Diabetes Technology Society.

Laser induced autofluorescence for diagnosis of non-melanoma skin cancer

NASA Astrophysics Data System (ADS)

Drakaki, E.; Makropoulou, M.; Serafetinides, A. A.; Merlemis, N.; Kalatzis, I.; Sianoudis, I. A.; Batsi, O.; Christofidou, E.; Stratigos, A. J.; Katsambas, A. D.; Antoniou, Ch.

2015-01-01

Non melanoma skin cancer is one of the most frequent malignant tumors among humans. A non-invasive technique, with high sensitivity and high specificity, would be the most suitable method for basal cell carcinoma (BCC) or other malignancies diagnostics, instead of the well established biopsy and histopathology examination. In the last decades, a non-invasive, spectroscopic diagnostic method was introduced, the laser induced fluorescence (LIF), which could generate an image contrast between different states of skin tissue. The noninvasiveness consists in that this biophotonic method do not require tissue sample excision, what is necessary in histopathology characterization and biochemical analysis of the skin tissue samples, which is worldwide used as an evaluation gold standard. The object of this study is to establish the possibilities of a relatively portable system for laser induced skin autofluorescence to differentiate malignant from nonmalignant skin lesions. Unstained human skin samples, excised from humans undergoing biopsy examination, were irradiated with a Nd:YAG-3ω laser (λ=355 nm, 6 ns), used as an excitation source for the autofluorescence measurements. A portable fiber-based spectrometer was used to record fluorescence spectra of the sites of interest. The ex vivo results, obtained with this spectroscopic technique, were correlated with the histopathology results. After the analysis of the fluorescence spectra of almost 60 skin tissue areas, we developed an algorithm to distinguish different types of malignant lesions, including inflammatory areas. Optimization of the data analysis and potential use of LIF spectroscopy with 355 nm Nd:YAG laser excitation of tissue autofluorescence for clinical applications are discussed.

H+- and Na+- elicited rapid changes of the microtubule cytoskeleton in the biflagellated green alga Chlamydomonas

PubMed Central

Liu, Yi; Visetsouk, Mike; Mynlieff, Michelle; Qin, Hongmin; Lechtreck, Karl F

2017-01-01

Although microtubules are known for dynamic instability, the dynamicity is considered to be tightly controlled to support a variety of cellular processes. Yet diverse evidence suggests that this is not applicable to Chlamydomonas, a biflagellate fresh water green alga, but intense autofluorescence from photosynthesis pigments has hindered the investigation. By expressing a bright fluorescent reporter protein at the endogenous level, we demonstrate in real time discreet sweeping changes in algal microtubules elicited by rises of intracellular H+ and Na+. These results from this model organism with characteristics of animal and plant cells provide novel explanations regarding how pH may drive cellular processes; how plants may respond to, and perhaps sense stresses; and how organisms with a similar sensitive cytoskeleton may be susceptible to environmental changes. PMID:28875932

Deceased-donor kidney transplantation in Iran: trends, barriers and opportunities.

PubMed

Einollahi, Behzad; Nourbala, Mohammad-Hossein; Bahaeloo-Horeh, Saeid; Assari, Shervin; Lessan-Pezeshki, Mahboob; Simforoosh, Naser

2007-01-01

Having enjoyed considerable success in kidney transplantation in recent years, Iran has been named the most active country in the Middle East Society for Organ Transplantation region in providing equitable quick, and intermediary-free access to affordable kidney transplantation for everyone regardless of gender and economic circumstances. We are, however, of the opinion that the Iranian model can benefit further from improving deceased-donor kidney transplantation, especially after a fatwa (Islamic edict) in the early 1980s lifted many religious and legal barriers. Deceased-donor kidney transplantation in Iran should be bolstered by establishing a transplantation model, increasing government funds, and encouraging participation of the general public in the Iranian Network for Transplant Organ Procurement. We recommend that an intensive media campaign be launched to heighten public awareness and more transplantation centres be involved in cadaveric transplantation with streamlined systems of cadaveric donations registration so as to facilitate the process of finding and relating the donors with potential recipients.

Single-hole hollow molecularly imprinted polymer embedded carbon dot for fast detection of tetracycline in honey.

PubMed

Li, Huiyu; Zhao, Li; Xu, Yuan; Zhou, Tianyu; Liu, Haochi; Huang, Ning; Ding, Jie; Li, Yi; Ding, Lan

2018-08-01

It is difficult to detect tetracycline (TC) in honey sample by using carbon dots (CDs) because the autofluorescence of the matrix of honey sample overlaps with the fluorescence emission spectrum of the large majority of CDs. Herein, single-hole hollow molecularly imprinted polymers embedded carbon dots (HMIP@CD) was prepared via microwave-assisted method. TC in diluted honey sample was adsorbed by the HMIP@CD within 3 min, after which the HMIP@CD absorbed with TC was separated by centrifugation from honey sample and redispersed into phosphate buffer solution. The autofluorescence of honey that interferes with the fluorescence signal of HMIP@CD was avoided. The method exhibited an excellent linearity within 10-200 μg L -1 and a low detection limit of 3.1 μg L -1 . At three spiking levels of TC, the recoveries ranged from 93% to 105% with precisions below 1.6%. This method provides an effective strategy for detecting analyte in complex matrix with autofluorescence interference. Copyright © 2018. Published by Elsevier B.V.

High sensitive fundus autofluorescence imaging combined with speckle-free optical coherence tomography

NASA Astrophysics Data System (ADS)

Stremplewski, Patrycjusz; Komar, Katarzyna; Szkulmowski, Maciej; Motoczyńska, Marta; Wojtkowski, Maciej

2013-03-01

Scattering and fluorescence images provide complementary information about the health condition of the human eye, so getting them in a single measurement, using a single device may significantly improve a quality of diagnosis as it has been already demonstrated in Spectralis (Heidelberg Eng.) OCT instrument. There is still challenge to improve quality of fundus autofluorescence (FAF) images. The biggest obstacle in obtaining in vivo images of sufficient quality is very low fluorescence signal. For eye safety reasons, and because of patient comfort, using highpower fluorescence excitation is not an adequate solution to the low signal problem. In this contribution we show a new detection method in the retinal autofluorescence imaging, which may improve the sensitivity. We used a fast modulated (up to 500 MHz) diode laser of wavelength 473 nm and detected fluorescence in the spectral range 500-680 nm by photomultiplier and lock-in amplifier. Average power of the collimated blue beam on the cornea used for FAF measurements was set to 50 μW, 10 μW, and even 4.5 μW.

Interpretation of measurements of dynamic fluorescence of the eye

NASA Astrophysics Data System (ADS)

Schweitzer, Dietrich; Hammer, Martin; Jentsch, Susanne; Schenke, Stefan

2007-09-01

First pathological alterations occur at cellular level, most in metabolism. An indirect estimation of metabolic activity in cells is measurement of microcirculation. Measurements of tissue autofluorescence are potentially suited for direct investigation of cellular metabolism. Besides redox pairs of co-enzymes (NADH-NAD, FADH2-FAD) several other fluorophores are excited in tissue. In addition, a number of anatomical structures are simultaneously excited, when investigating the eye-ground. In this study, spectral and time resolved comparison was performed between purified substances, single ocular structures and in vivo measurements of the time-resolved autofluorescence at the human eye. In human eyes, the ageing pigment lipofuscin covers other fluorophores at the fundus in long - wave visible range. Applying lifetime measurements, weakly emitting fluorophores can be detected, when the lifetimes are different from the strongly emitting fluorophore. For this, the autofluorescence was excited at 468 nm and detected in two spectral ranges (500 nm-560 nm, 560 nm-700 nm). In tri-exponential fitting, the short lifetime corresponds to retinal pigment epithelium, the mean lifetime corresponds probably to neural retina and the long lifetime is caused by fluorescence of connective tissue.

Trimodal detection of early childhood caries using laser light scanning and fluorescence spectroscopy: clinical prototype

PubMed Central

Kim, Amy S.; Ridge, Jeremy S.; Nelson, Leonard Y.; Berg, Joel H.; Seibel, Eric J.

2013-01-01

Abstract. There is currently a need for a safe and effective way to detect and diagnose early stages of childhood caries. A multimodal optical clinical prototype for diagnosing caries demineralization in vivo has been developed. The device can be used to quickly image and screen for any signs of demineralized enamel by obtaining high-resolution and high-contrast surface images using a 405-nm laser as the illumination source, as well as obtaining autofluorescence and bacterial fluorescence images. When a suspicious region of demineralization is located, the device also performs dual laser fluorescence spectroscopy using 405- and 532-nm laser excitation. An autofluorescence ratio of the two excitation lasers is computed and used to quantitatively diagnose enamel health. The device was tested on five patients in vivo as well as on 28 extracted teeth with clinically diagnosed carious lesions. The device was able to provide detailed images that highlighted the lesions identified by the clinicians. The autofluorescence spectroscopic ratios obtained from the extracted teeth successfully quantitatively discriminated between sound and demineralized enamel. PMID:23986369

Fundus autofluorescence and optical coherence tomography in the management of progressive outer retinal necrosis

PubMed Central

Yeh, Steven; Wong, Wai T.; Weichel, Eric D.; Lew, Julie C.; Chew, Emily Y.; Nussenblatt, Robert B.

2011-01-01

A 41 year-old female patient with acquired immune deficiency syndrome (AIDS) presented with progressive nasal visual field loss in her right eye. Ophthalmic exam revealed widespread areas of retinal opacification with hemorrhage consistent with progressive outer retinal necrosis (PORN), which was confirmed by polymerase chain reaction (PCR) for varicella zoster virus (VZV) DNA. The patient was treated with intravenous and intravitreal foscarnet and ganciclovir with a resultant improvement clinically. Optical coherence tomography (OCT) and fundus autofluorescence (FAF) imaging revealed progressive changes indicative of widespread retinal pigment epithelial (RPE) and outer retinal dysfunction. OCT was useful in documenting progressive changes in macular architecture during therapy including neurosensory elevation, cystoid macular edema, and severe outer retinal necrosis, at initial exam, 1 week, and 1 month follow-up. Fundus autofluorescence revealed areas of stippled, hyperfluorescence within extensive zones of hypofluorescence, which progressed during the follow-up period. These areas appeared to represent lipofuscin or its photoreactive components within larger regions of RPE loss. The combination of OCT and FAF was useful in the characterization of the RPE and retinal anatomy in this patient with PORN. PMID:20337261

Autofluorescence lifetime metrology for label-free detection of cartilage matrix degradation

NASA Astrophysics Data System (ADS)

Nickdel, Mohammad B.; Lagarto, João. L.; Kelly, Douglas J.; Manning, Hugh B.; Yamamoto, Kazuhiro; Talbot, Clifford B.; Dunsby, Christopher; French, Paul; Itoh, Yoshifumi

2014-03-01

Degradation of articular cartilage extracellular matrix (ECM) by proteolytic enzyme is the hallmark of arthritis that leads to joint destruction. Detection of early biochemical changes in cartilage before irreversible structural damages become apparent is highly desirable. Here we report that the autofluorescence decay profile of cartilage is significantly affected by proteolytic degradation of cartilage ECM and can be characterised by measurements of the autofluorescence lifetime (AFL). A multidimensional fluorometer utilizing ultraviolet excitation at 355 nm or 375 nm coupled to a fibreoptic probe was developed for single point time-resolved AFL measurements of porcine articular cartilage explants treated with different proteinases. Degradation of cartilage matrix components by treating with bacterial collagenase, matrix metalloproteinase 1, or trypsin resulted in significant reduction of AFL of the cartilage in both a dose and time dependent manner. Differences in cartilage AFL were also confirmed by fluorescence lifetime imaging microscopy (FLIM). Our data suggest that AFL of cartilage tissue is a potential non-invasive readout to monitor cartilage matrix integrity that may be utilized for diagnosis of arthritis as well as monitoring the efficacy of anti-arthritic therapeutic agents.

Qualitative and quantitative characteristics of near-infrared autofluorescence in diabetic macular edema.

PubMed

Yoshitake, Shin; Murakami, Tomoaki; Horii, Takahiro; Uji, Akihito; Ogino, Ken; Unoki, Noriyuki; Nishijima, Kazuaki; Yoshimura, Nagahisa

2014-05-01

To study the characteristics of near-infrared autofluorescence (NIR-AF) imaging and its association with spectral-domain optical coherence tomography (SD-OCT) findings and logarithm of the minimal angle of resolution (logMAR) visual acuity (VA) in diabetic macular edema (DME). Retrospective, observational, cross-sectional study. One hundred twenty-one consecutive eyes of 87 patients with center-involved DME for whom NIR-AF and SD-OCT images of sufficient quality were obtained. The NIR-AF images were acquired using Heidelberg Retina Angiograph 2 (Heidelberg Engineering, Heidelberg, Germany), and sectional retinal images were obtained using Spectralis OCT (Heidelberg Engineering). The presence of a mosaic pattern and cystoid signs were determined qualitatively. We quantified the average fluorescence intensity in the central 1-mm subfield. The characteristics of the NIR-AF images were compared with the OCT findings and logMAR VA. Qualitative and quantitative characteristics of the NIR-AF images and their association with SD-OCT findings and logMAR VA. Fifty-seven eyes with a mosaic pattern in the NIR-AF macular images had worse logMAR VA (0.355±0.239 vs. 0.212±0.235; P = 0.001), a thicker central subfield (CSF) (530±143 μm vs. 438±105 μm; P <0.001), and disrupted external limiting membrane (ELM; P <0.001) compared with 64 eyes without these findings. Forty-one eyes with a cystoid sign in the NIR-AF images had worse logMAR VA (0.393±0.233 vs. 0.221±0.234; P <0.001) and a thicker CSF (557±155 μm vs. 443±100 μm; P <0.001) than those without them; there were no significant differences in the ELM status. The relative fluorescence intensity in the central subfield in the NIR-AF images was correlated negatively with the CSF thickness and logMAR VA (R = 0.492, P <0.001 and R = 0.377, P <0.001, respectively). Eyes with foveal serous retinal detachment had lower levels of relative fluorescence intensity than those without it (0.751±0.191 vs. 0.877±0.154; P = 0.007); there was no association with the presence of foveal cystoid spaces, disrupted ELM, or hyperreflective foci in the outer retinal layers. Novel qualitative and quantitative NIR-AF characteristics in the macula indicated the clinical relevance and suggested the pathogenesis in DME. Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

[Acute kidney injury-emergency or coincidence?].

PubMed

Öttl, Tobias

2013-02-27

An unifying definition of acute kidney injury as a precursor of acute renal failure has been published in march last year. Its remarkable mortality makes an early diagnosis an important goal. New biomarkers will be an important step to reach this goal in the near future. Depending on the underlying cause, therapeutic actions should be realized as soon as possible to diminish in-hospital mortality and chronic nephropathy. Intensive care units often are the first to test for new active substances.

Detection of carcinogenic metals in kidney stones using ultraviolet laser-induced breakdown spectroscopy.

PubMed

Khalil, Ahmed Asaad I; Gondal, Mohammed A; Shemis, Mohamed; Khan, Irfan S

2015-03-10

The UV single-pulsed (SP) laser-induced breakdown spectroscopy (LIBS) system was developed to detect the carcinogenic metals in human kidney stones extracted through the surgical operation. A neodymium yttrium aluminium garnet laser operating at 266 nm wavelength and 20 Hz repetition rate along with a spectrometer interfaced with an intensified CCD (ICCD) was applied for spectral analysis of kidney stones. The ICCD camera shutter was synchronized with the laser-trigger pulse and the effect of laser energy and delay time on LIBS signal intensity was investigated. The experimental parameters were optimized to obtain the LIBS plasma in local thermodynamic equilibrium. Laser energy was varied from 25 to 50 mJ in order to enhance the LIBS signal intensity and attain the best signal to noise ratio. The parametric dependence studies were important to improve the limit of detection of trace amounts of toxic elements present inside stones. The carcinogenic metals detected in kidney stones were chromium, cadmium, lead, zinc, phosphate, and vanadium. The results achieved from LIBS system were also compared with the inductively coupled plasma-mass spectrometry analysis and the concentration detected with both techniques was in very good agreement. The plasma parameters (electron temperature and density) for SP-LIBS system were also studied and their dependence on incident laser energy and delay time was investigated as well.

Label-free assessment of endothelial cell metabolic state using autofluorescent microscopy

NASA Astrophysics Data System (ADS)

Pullen, Benjamin J.; Nguyen, Tam; Gosnell, Martin; Anwer, Ayad G.; Goldys, Ewa; Nicholls, Stephen J.; Psaltis, Peter J.

2016-12-01

To examine the process of endothelial cell aging we utilised hyperspectral imaging to collect broad autofluorescence emission at the individual cellular level and mathematically isolate the characteristic spectra of nicotinamide and flavin adenine dinucleotides (NADH and FAD, respectively). Quantitative analysis of this data provides the basis for a non-destructive spatial imaging method for cells and tissue. FAD and NADH are important factors in cellular metabolism and have been shown to be involved with the redox state of the cell; with the ratio between the two providing the basis for an `optical redox ratio'.

Density-based clustering analyses to identify heterogeneous cellular sub-populations

NASA Astrophysics Data System (ADS)

Heaster, Tiffany M.; Walsh, Alex J.; Landman, Bennett A.; Skala, Melissa C.

2017-02-01

Autofluorescence microscopy of NAD(P)H and FAD provides functional metabolic measurements at the single-cell level. Here, density-based clustering algorithms were applied to metabolic autofluorescence measurements to identify cell-level heterogeneity in tumor cell cultures. The performance of the density-based clustering algorithm, DENCLUE, was tested in samples with known heterogeneity (co-cultures of breast carcinoma lines). DENCLUE was found to better represent the distribution of cell clusters compared to Gaussian mixture modeling. Overall, DENCLUE is a promising approach to quantify cell-level heterogeneity, and could be used to understand single cell population dynamics in cancer progression and treatment.

Endomicroscopy imaging of epithelial structures using tissue autofluorescence

NASA Astrophysics Data System (ADS)

Lin, Bevin; Urayama, Shiro; Saroufeem, Ramez M. G.; Matthews, Dennis L.; Demos, Stavros G.

2011-04-01

We explore autofluorescence endomicroscopy as a potential tool for real-time visualization of epithelial tissue microstructure and organization in a clinical setting. The design parameters are explored using two experimental systems--an Olympus Medical Systems Corp. stand-alone clinical prototype probe, and a custom built bench-top rigid fiber conduit prototype. Both systems entail ultraviolet excitation at 266 nm and/or 325 nm using compact laser sources. Preliminary results using ex vivo animal and human tissue specimens suggest that this technology can be translated toward in vivo application to address the need for real-time histology.

Comparison of time-resolved autofluorescence in the eye-ground of healthy subjects and patients suffering from age-related macular degeneration

NASA Astrophysics Data System (ADS)

Schweitzer, Dietrich; Schweitzer, Frank; Hammer, Martin; Schenke, Stefan; Richter, Sandra

2005-08-01

Age-related macular degeneration (AMD) is the most frequent cause for blindness for person older than 65 years in western countries. Besides the subjective pain, it is also an economic problem in the ageing population. As the pathomechanism is unknown, no curative treatment is possible. International research for discovering of early age-related alterations at the fundus is directed on in vivo measurements of autofluorescence. One way is the measurement of fluorescence spectra. Unfortunately, any selective excitation of fluorophores is excluded by the absorption edge of the ocular media at 400 nm. Furthermore, the shape of fluorescence spectra is influenced by the spectral absorption of layers in front of the emitting fluorophore. Weakly emitting fluorophores are covered by intensive emitting substances. The most serious limitation in fluorescence measurements of the living human fundus is the maximal permissible exposure. For that reason, fluorescence spectra of the fundus can not be detected with a high spatial resolution. The detection of dynamic fluorescence provides substance-specific lifetimes Ti, amplitudes Ai, and information about the relative contribution Qi of components in fluorescence images. As these parameters are calculated for each image point, diagrams of Ti vs. Tj, Ai vs. Aj, and Qi vs. Qj can be drawn, in which specific clusters appear for healthy subjects or AMD - patients. The projection of lifetime - clusters onto corresponding axis represents histogram of the considered lifetime. The slope in the correlation between Ai and Aj can also be used as a discriminating mark. Considering image lines as intersection through characteristic anatomical structures (optic disc, macula) profiles of Ti, Ai, or Qi show changes of these parameters (e.g. depigmentation) as function of location, which might be specific for AMD.

Autofluorescence imaging of macular pigment: influence and correction of ocular media opacities

NASA Astrophysics Data System (ADS)

Sharifzadeh, Mohsen; Obana, Akira; Gohto, Yuko; Seto, Takahiko; Gellermann, Werner

2014-09-01

The healthy adult human retina contains in its macular region a high concentration of blue-light absorbing carotenoid compounds, known as macular pigment (MP). Consisting of the carotenoids lutein, zeaxanthin, and meso-zeaxanthin, the MP is thought to shield the vulnerable tissue layers in the retina from light-induced damage through its function as an optical attenuator and to protect the tissue cells within its immediate vicinity through its function as a potent antioxidant. Autofluorescence imaging (AFI) is emerging as a viable optical method for MP screening of large subject populations, for tracking of MP changes over time, and for monitoring MP uptake in response to dietary supplementation. To investigate the influence of ocular media opacities on AFI-based MP measurements, in particular, the influence of lens cataracts, we conducted a clinical trial with a large subject population (93 subjects) measured before and after cataract surgery. General AFI image contrast, retinal blood vessel contrast, and presurgery lens opacity scores [Lens Opacities Classification System III (LOCS III)] were investigated as potential predictors for image degradation. These clinical results show that lens cataracts can severely degrade the achievable pixel contrasts in the AFI images, which results in nominal MP optical density levels that are artifactually reduced. While LOCS III scores and blood vessel contrast are found to be only a weak predictor for this effect, a strong correlation exists between the reduction factor and the image contrast, which can be quantified via pixel intensity histogram parameters. Choosing the base width of the histogram, the presence or absence of ocular media opacities can be determined and, if needed, the nominal MP levels can be corrected with factors depending on the strength of the opacity.

Effects of a simulated martian UV flux on the cyanobacterium, Chroococcidiopsis sp. 029.

PubMed

Cockell, Charles S; Schuerger, Andrew C; Billi, Daniela; Friedmann, E Imre; Panitz, Corinna

2005-04-01

Dried monolayers of Chroococcidiopsis sp. 029, a desiccation-tolerant, endolithic cyanobacterium, were exposed to a simulated martian-surface UV and visible light flux, which may also approximate to the worst-case scenario for the Archean Earth. After 5 min, there was a 99% loss of cell viability, and there were no survivors after 30 min. However, this survival was approximately 10 times higher than that previously reported for Bacillus subtilis. We show that under 1 mm of rock, Chroococcidiopsis sp. could survive (and potentially grow) under the high martian UV flux if water and nutrient requirements for growth were met. In isolated cells, phycobilisomes and esterases remained intact hours after viability was lost. Esterase activity was reduced by 99% after a 1-h exposure, while 99% loss of autofluorescence required a 4-h exposure. However, cell morphology was not changed, and DNA was still detectable by 4',6-diamidino-2-phenylindole staining after an 8-h exposure (equivalent to approximately 1 day on Mars at the equator). Under 1 mm of simulant martian soil or gneiss, the effect of UV radiation could not be detected on esterase activity or autofluorescence after 4 h. These results show that under the intense martian UV flux the morphological signatures of life can persist even after viability, enzymatic activity, and pigmentation have been destroyed. Finally, the global dispersal of viable, isolated cells of even this desiccation-tolerant, ionizing-radiation-resistant microorganism on Mars is unlikely as they are killed quickly by unattenuated UV radiation when in a desiccated state. These findings have implications for the survival of diverse microbial contaminants dispersed during the course of human exploratory class missions on the surface of Mars.

Detecting De-gelation through Tissue Using Magnetically Modulated Optical Nanoprobes (MagMOONs)

PubMed Central

Nguyen, KhanhVan T.; Anker, Jeffrey N.

2014-01-01

Alginate gels are widely used for drug delivery and implanted devices. The rate at which these gels break down is important for controlling drug release. Since the de-gelation may be different in vivo, monitoring this process in situ is essential. However, it is challenging to monitor the gel through tissue due to optical scattering and tissue autofluorescence. Herein we describe a method to detect through tissue the chemically-induced changes in viscosity and de-gelation process of alginate gels using magnetically modulated optical nanoprobes (MagMOONs). The MagMOONs are fluorescent magnetic microspheres coated with a thin layer of opaque metal on one hemisphere. The metal layer prevents excitation and emission light from passing through one side of the MagMOONs, which creates orientation-dependent fluorescence intensity. The magnetic particles also align in an external magnetic field and give blinking signals when they rotate to follow an external modulated magnetic field. The blinking signals from these MagMOONs are distinguished from background autofluorescence and can be tracked on a single particle level in the absence of tissue, or for an ensemble average of particles blinking through tissue. When these MagMOONs are dispersed in calcium alginate gel, they become sensors for detecting gel degradation upon addition of either ammonium ion or alginate lyase. Our results show MagMOONs start blinking approximately 10 minutes after 2 mg/mL alginate lyase addition and this blinking is clearly detected even through up to 4 mm chicken breast. This approach can potentially be employed to detect bacterial biofilm formation on medical implants by sensing specific proteases that either activate a related function or regulate biofilm formation. It can also be applied to other biosensors and drug delivery systems based on enzyme-catalyzed breakdown of gel components. PMID:26273129

Detecting De-gelation through Tissue Using Magnetically Modulated Optical Nanoprobes (MagMOONs).

PubMed

Nguyen, KhanhVan T; Anker, Jeffrey N

2014-12-15

Alginate gels are widely used for drug delivery and implanted devices. The rate at which these gels break down is important for controlling drug release. Since the de-gelation may be different in vivo , monitoring this process in situ is essential. However, it is challenging to monitor the gel through tissue due to optical scattering and tissue autofluorescence. Herein we describe a method to detect through tissue the chemically-induced changes in viscosity and de-gelation process of alginate gels using magnetically modulated optical nanoprobes (MagMOONs). The MagMOONs are fluorescent magnetic microspheres coated with a thin layer of opaque metal on one hemisphere. The metal layer prevents excitation and emission light from passing through one side of the MagMOONs, which creates orientation-dependent fluorescence intensity. The magnetic particles also align in an external magnetic field and give blinking signals when they rotate to follow an external modulated magnetic field. The blinking signals from these MagMOONs are distinguished from background autofluorescence and can be tracked on a single particle level in the absence of tissue, or for an ensemble average of particles blinking through tissue. When these MagMOONs are dispersed in calcium alginate gel, they become sensors for detecting gel degradation upon addition of either ammonium ion or alginate lyase. Our results show MagMOONs start blinking approximately 10 minutes after 2 mg/mL alginate lyase addition and this blinking is clearly detected even through up to 4 mm chicken breast. This approach can potentially be employed to detect bacterial biofilm formation on medical implants by sensing specific proteases that either activate a related function or regulate biofilm formation. It can also be applied to other biosensors and drug delivery systems based on enzyme-catalyzed breakdown of gel components.

The Quality of In Vivo Upconversion Fluorescence Signals Inside Different Anatomic Structures.

PubMed

Wang, Lijiang; Draz, Mohamed Shehata; Wang, Wei; Liao, Guodong; Xu, Yuhong

2015-02-01

Fluorescence imaging is a broadly interesting and rapidly growing strategy for non-invasive clinical applications. However, because of interference from light scattering, absorbance, and tissue autofluorescence, the images can exhibit low sensitivity and poor quality. Upconversion fluorescence imaging, which is based on the use of near-infrared (NIR) light for excitation, has recently been introduced as an improved approach to minimize the effects of light scattering and tissue autofluorescence. This strategy is promising for ultrasensitive and deep tissue imaging applications. However, the emitted upconversion fluorescence signals are primarily in the visible range and are likely to be absorbed and scattered by tissues. Therefore, different anatomic structures could impose various effects on the quality of the images. In this study, we used upconversion-core/silica-shell nanoprobes to evaluate the quality of upconversion fluorescence at different anatomic locations in athymic nude mice. The nanoprobe contained an upconversion core, which was green (β-NaYF4:Yb3+/Ho3+) or red (β-NaYF4:Yb3+/Er3+), and a nonporous silica shell to allow for multicolor imaging. High-quality upconversion fluorescence signals were detected with signal-to-noise ratios of up to 170 at tissue depths of up to - 1.0 cm when a 980 nm laser excitation source and a bandpass emission filter were used. The presence of dense tissue structures along the imaging path reduced the signal intensity and imaging quality, and nanoprobes with longer-wavelength emission spectra were therefore preferable. This study offers a detailed analysis of the quality of upconversion signals in vivo inside different anatomic structures. Such information could be essential for the analysis of upconversion fluorescence images in any in vivo biodiagnostic and microbial tracking applications.

Microscopic fluorescence spectral analysis of basal cell carcinomas

NASA Astrophysics Data System (ADS)

He, Qingli; Lui, Harvey; Zloty, David; Cowan, Bryce; Warshawski, Larry; McLean, David I.; Zeng, Haishan

2007-05-01

Background and Objectives. Laser-induced autofluorescence (LIAF) is a promising tool for cancer diagnosis. This method is based on the differences in autofluorescence spectra between normal and cancerous tissues, but the underlined mechanisms are not well understood. The objective of this research is to study the microscopic origins and intrinsic fluorescence properties of basal cell carcinoma (BCC) for better understanding of the mechanism of in vivo fluorescence detection and margin delineation of BCCs on skin patients. A home-made micro- spectrophotometer (MSP) system was used to image the fluorophore distribution and to measure the fluorescence spectra of various microscopic structures and regions on frozen tissue sections. Materials and Methods. BCC tissue samples were obtained from 14 patients undergoing surgical resections. After surgical removal, each tissue sample was immediately embedded in OCT medium and snap-frozen in liquid nitrogen. The frozen tissue block was then cut into 16-μm thickness sections using a cryostat microtome and placed on microscopic glass slides. The sections for fluorescence study were kept unstained and unfixed, and then analyzed by the MSP system. The adjacent tissue sections were H&E stained for histopathological examination and also served to help identify various microstructures on the adjacent unstained sections. The MSP system has all the functions of a conventional microscope, plus the ability of performing spectral analysis on selected micro-areas of a microscopic sample. For tissue fluorescence analysis, 442nm He-Cd laser light is used to illuminate and excite the unstained tissue sections. A 473-nm long pass filter was inserted behind the microscope objective to block the transmitted laser light while passing longer wavelength fluorescence signal. The fluorescence image of the sample can be viewed through the eyepieces and also recorded by a CCD camera. An optical fiber is mounted onto the image plane of the photograph port of the microscope to collect light from a specific micro area of the sample. The collected light is transmitted via the fiber to a disperserve type CCD spectrometer for spectral analysis. Results. The measurement results showed significant spectral differences between normal and cancerous tissues. For normal tissue regions, the spectral results agreed with our previous findings on autofluorescence of normal skin sections. For the cancerous regions, the epidermis showed very weak fluorescence signal, while the stratum corneum exhibited fluorescence emissions peaking at about 510 nm. In the dermis, the basal cell island and a band of surrounding areas showed very weak fluorescence signal, while distal dermis above and below the basal cell island showed greater fluorescence signal but with different spectral shapes. The very weak autofluorescence from the basal cell island and its surrounding area may be attributed to their degenerative properties that limited the production of collagens. Conclusions. The obtained microscopic results very well explain the in vivo fluorescence properties of BCC lesions in that they have decreased fluorescence intensity compared to the surrounding normal skin. The intrinsic spectra of various microstructures and the microscopic fluorescence images (corresponding fluorophore distribution in tissue) obtained in this study will be used for further theoretical modeling of in vivo fluorescence spectroscopy and imaging of skin cancers.

Advantages of T2 Weighted Three Dimensional and T1 Weighted Three Dimensional Contrast Medium Enhanced Magnetic Resonance Urography in Examination of the Child Population.

PubMed

Sehic, Adnan; Julardzija, Fuad; Vegar-Zubovic, Sandra; Sefic-Pasic, Irmina

2017-03-01

The aim of this study is to prove the advantages of combined use of T2 weighted three dimensional (T2 W 3D) and T1 weighted three dimensional contrast medium enhanced (T1 W 3D CE) magnetic resonance (MR) urography in displaying urinary tract in child population. Total of 120 patients were included in the study, 71 (59%) male patients and 49 (41%) female patients. The study was conducted on the Radiology clinic, University of Sarajevo Clinical Center, during the period from February to November 2016. Patients were examined on the 1.5T and 3T MRI, with standard protocol which includes T2 W 3D and T1 W 3D contrast medium enhanced MR urography. In the post procesing quantitative measurement of signal intensity and evaluation of the display quality in the area of renal pelvis, middle of ureter and the mouth of the ureter were done. Measurement was concluded on Syngo software B13. Analyzing the acquired data and statistically processing them we got results which have shown higher signal intensity of measured structures on T1 W 3D contrast medium enhanced MR urography on the level p<0.01 and p<0.05 compared to T2 W 3D MR urography in patients that had normal dynamics of contrast medium secretion. However, in kidneys with decreased function, T2 W 3D MR urography provided higher signal intensity and better display compared to T1 W 3D contrast medium enhanced MR urography on the level p<0.05 and p<0.01. T2 W3D MR urography is useful in imaging nonfunctional kidney as well as in patients prone to allergic reactions, where as T1 W3D CE MR urography is at an advantage over T2 W 3D MR urography in imaging the kidney functionality, kidney dynamics measurement, it provides higher MRI signal intensity required for clear 3D reconstructions.

The Importance of Residual Kidney Function in Haemodialysis Patients.

PubMed

Kong, Jessica; Davies, Matthew; Mount, Peter

2018-06-19

In contrast to peritoneal dialysis, residual kidney function is commonly disregarded for haemodialysis patients, and not regularly monitored or taken into account in routine clinical care. This is despite evidence that higher levels of residual kidney function in haemodialysis patients associate with better outcomes including survival, total solute clearance, nutrition, inflammation, and fluid balance. This review aims to summarise the clinical effects of residual kidney function specifically in haemodialysis patients. Some level of residual kidney function is present in over 80% of patients at the time of dialysis initiation, and while this declines over time, up to 30% of patients on haemodialysis for 5 years still have a measurable level of native kidney function. There is little evidence on how best to preserve residual kidney function in haemodialysis patients, although it has been observed that intensive haemodialysis regimens in incident haemodialysis patients appear to accelerate residual kidney function decline. Residual kidney function is not commonly factored in to haemodialysis prescription and measures of adequacy, despite the fact that some guidelines such as KDOQI and European Best Practice Guidelines suggest that it is reasonable to do. This likely relates, at least in part, to perceived concerns regarding the inconvenience of timed urine collections, and to the complexity and lack of consensus regarding the methods for integrating the intermittent clearance of haemodialysis with the continuous clearance of native renal function. Further research is required into how best to maintain and maximise the benefits of residual kidney function in haemodialysis patients. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Assessing Intrarenal Non-perfusion and Vascular Leakage in Acute Kidney Injury withzz 19F MRI and Perfluorocarbon Nanoparticles

PubMed Central

Hu, Lingzhi; Chen, Junjie; Yang, Xiaoxia; Senpan, Angana; Allen, John S.; Yanaba, Noriko; Caruthers, Shelton D.; Lanza, Gregory M.; Hammerman, Marc R.; Wickline, Samuel A.

2014-01-01

Purpose We sought to develop a unique sensor-reporter approach for functional kidney imaging that employs circulating perfluorocarbon nanoparticles (PFC NPs) and 19F MRI. Methods Because the detected 19F signal intensity directly reflects local blood volume, and the 19F R1 is linearly proportional to local blood oxygen content (pO2), 19F spin density weighted and T1 weighted images were utilized to generate quantitative functional mapping in both healthy and ischemia-reperfusion (acute kidney injury, AKI) injured mouse kidneys. 1H Blood-Oxygenation-Level-Dependant (BOLD) MRI was also employed as a supplementary approach to facilitate the compressive analysis of renal circulation and its pathological changes in AKI. Results Heterogeneous blood volume distribution and intrarenal oxygenation gradient were confirmed in healthy kidneys by 19F MRI. In a mouse model of AKI, 19F MRI, in conjunction with BOLR MRI, sensitively delineated renal vascular damage and recovery. In the cortico-medullary (CM) junction region, we observed 25% lower 19F signal (p<0.05) and 70% longer 1H T2* (p<0.01) in injured kidneys compared to contralateral kidneys at 24 hours after initial ischemia-reperfusion injury. We also detected 71% higher 19F signal (p<0.01) and 40% lower 1H T2* (p<0.05) in the renal medulla region of injured kidneys compared to contralateral kidneys. Conclusion With demonstrated superior diagnostic capability, functional kidney 19F MRI using PFC NPs could serve as a new diagnostic measures for comprehensive evaluation of renal function and pathology. PMID:23929727

Effects of cyclosporin A on a kidney epithelial cell line (LLC-PK1).

PubMed

Becker, G M; Gandolfi, A J; Nagle, R B

1987-05-01

Cyclosporin A (CSA), a potent immunosuppressant with the adverse side effect of nephrotoxicity, inhibited cell growth of pig kidney tubule cells (LLC-PK1) in culture. CSA (10(-5) M) also induced intense cytoplasmic vacuolation and the formation of dense granules. At the same concentration an analogue of CSA, cyclosporin G, had much less effect. This cell line may prove useful for revealing the mechanism of CSA-nephrotoxicity and testing the nephrotoxic potential of new analogues of cyclosporine.

Dual Kidney Allocation Score: A Novel Algorithm Utilizing Expanded Donor Criteria for the Allocation of Dual Kidneys in Adults.

PubMed

Johnson, Adam P; Price, Thea P; Lieby, Benjamin; Doria, Cataldo

2016-09-08

BACKGROUND Dual kidney transplantation (DKT) of expanded-criteria donors is a cost-intensive procedure that aims to increase the pool of available deceased organ donors and has demonstrated equivalent outcomes to expanded-criteria single kidney transplantation (eSKT). The objective of this study was to develop an allocation score based on predicted graft survival from historical dual and single kidney donors. MATERIAL AND METHODS We analyzed United Network for Organ Sharing (UNOS) data for 1547 DKT and 26 381 eSKT performed between January 1994 and September 2013. We utilized multivariable Cox regression to identify variables independently associated with graft survival in dual and single kidney transplantations. We then derived a weighted multivariable product score from calculated hazard ratios to model the benefit of transplantation as dual kidneys. RESULTS Of 36 donor variables known at the time of listing, 13 were significantly associated with graft survival. The derived dual allocation score demonstrated good internal validity with strong correlation to improved survival in dual kidney transplants. Donors with scores less than 2.1 transplanted as dual kidneys had a worsened median survival of 594 days (24%, p-value 0.031) and donors with scores greater than 3.9 had improved median survival of 1107 days (71%, p-value 0.002). There were 17 733 eSKT (67%) and 1051 DKT (67%) with scores in between these values and no differences in survival (p-values 0.676 and 0.185). CONCLUSIONS We have derived a dual kidney allocation score (DKAS) with good internal validity. Future prospective studies will be required to demonstrate external validity, but this score may help to standardize organ allocation for dual kidney transplantation.

Skin autofluorescence is associated with arterial stiffness and insulin level in endurance runners and healthy controls - Effects of aging and endurance exercise.

PubMed

Couppé, Christian; Dall, Christian Have; Svensson, Rene Brüggebusch; Olsen, Rasmus Huan; Karlsen, Anders; Praet, Stephan; Prescott, Eva; Magnusson, S Peter

2017-05-01

Life-long regular endurance exercise yields positive effects on cardiovascular and metabolic function, disease and mortality rate. Glycation may be a major mechanism behind age-related diseases. However, it remains unknown if skin autofluorescence (SAF), which reflects glycation, is related to arterial and metabolic function in life-long endurance runners and sedentary controls. Healthy elderly men: 15 life-long endurance runners (OT) (64±4years) and 12 old untrained (OU) (66±4years), and healthy young men; ten young athletes (YT) (26±4years) matched to OT for running distance, and 12 young untrained (YU) (24±3years) were recruited. Endothelial function (reactive hyperemia index, RHI) and arterial stiffness (augmentation index, AI@75 and AI) were measured by an operator-independent PAT 2000. SAF was non-invasively determined using an autofluorescence spectrometer. For AI@75 there was an effect of age (p<0.0001), but not training (p=0.71). There was an interaction for endothelial function (p<0.05): YT had higher RHI than YU (p<0.05) and OU (p<0.01). SAF was associated with arterial stiffness (r 2 =0.57, p<0.001), insulin and HOMA-index levels after age correction (both r 2 =0.19, p<0.05). To our knowledge, these are the first data to show that skin autofluorescence (SAF) is linked to human arterial stiffness and insulin resistance in well-trained elderly and young men as well as sedentary controls. SAF may in the future be a helpful tool to predict vascular and metabolic dysfunction (early signs of aging and pathology). Surprisingly, endurance running only had modest effects on cardiovascular function compared to lean healthy controls. Copyright © 2017 Elsevier Inc. All rights reserved.

EVALUATION OF PATCHY ATROPHY SECONDARY TO HIGH MYOPIA BY SEMIAUTOMATED SOFTWARE FOR FUNDUS AUTOFLUORESCENCE ANALYSIS.

PubMed

Miere, Alexandra; Capuano, Vittorio; Serra, Rita; Jung, Camille; Souied, Eric; Querques, Giuseppe

2017-05-31

To evaluate the progression of patchy atrophy in high myopia using semiautomated software for fundus autofluorescence (FAF) analysis. The medical records and multimodal imaging of 21 consecutive highly myopic patients with macular chorioretinal patchy atrophy (PA) were retrospectively analyzed. All patients underwent repeated fundus autofluorescence and spectral domain optical coherence tomography over at least 12 months. Color fundus photography was also performed in a subset of patients. Total atrophy area was measured on FAF images using Region Finder semiautomated software embedded in Spectralis (Heidelberg Engineering, Heidelberg, Germany) at baseline and during follow-up visits. Region Finder was compared with manually measured PA on FAF images. Twenty-two eyes of 21 patients (14 women, 7 men; mean age 62.8 + 13.0 years, range 32-84 years) were included. Mean PA area using Region Finder was 2.77 ± 2.91 SD mm at baseline, 3.12 ± 2.68 mm at Month 6, 3.43 ± 2.68 mm at Month 12, and 3.73 ± 2.74 mm at Month 18 (overall P < 0.005); this accounts for PA progression rate of 0.821 mm/year. Atrophy progression was significantly greater among eyes with larger PA compared with smaller baseline PA at Months 6, 12, and 18. There was no statistically significant difference between semiautomated Region Finder PA area and manually measured PA area on FAF images. Fundus autofluorescence analysis by Region Finder semiautomated software provides accurate measurements of lesion area and allows us to quantify the progression of PA in high myopia. In our series, PA enlarged significantly over at least 12 months, and its progression seemed to be related to the lesion size at baseline.

MACULAR ATROPHY FINDINGS BY OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY COMPARED WITH FUNDUS AUTOFLUORESCENCE IN TREATED EXUDATIVE AGE-RELATED MACULAR DEGENERATION.

PubMed

Takasago, Yukari; Shiragami, Chieko; Kobayashi, Mamoru; Osaka, Rie; Ono, Aoi; Yamashita, Ayana; Tsujikawa, Akitaka; Hirooka, Kazuyuki

2017-11-28

To compare the areas of choriocapillaris (CC) nonperfusion and macular atrophy (MA) in treated exudative age-related macular degeneration. This was a prospective, observational, cross-sectional study. Forty-four eyes exhibiting MA (42 patients with age-related macular degeneration), with a dry macula, underwent fundus autofluorescence and optical coherence tomography angiography. The area of MA detected by fundus autofluorescence and CC nonperfusion detected by optical coherence tomography angiography was measured using image analysis software. The rates of concordance between the MA and CC nonperfusion areas were calculated. We qualitatively and quantitatively compared the areas of MA and CC nonperfusion in age-related macular degeneration eyes. The mean areas of MA and CC nonperfusion were 5.95 ± 4.50 mm and 10.66 ± 7.05 mm, respectively (paired t-test, P < 0.001). In 39 eyes (88.6%), the CC nonperfusion area was larger than the MA area, and the mean CC nonperfusion area was significantly larger than the mean MA area. Fundus autofluorescence matching optical coherence tomography angiography showed that the CC nonperfusion area was almost included in the MA area. The mean concordance rate for the MA area inside the CC nonperfusion area was 87.7 ± 13.9%. The MA and CC nonperfusion areas markedly overlapped. The area of CC nonperfusion correlated with the MA area. Choroidal ischemia might be involved in the pathogenesis of MA in treated age-related macular degeneration.This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The susceptibility of the retina to photochemical damage from visible light

PubMed Central

Hunter, Jennifer J; Morgan, Jessica I W; Merigan, William H; Sliney, David H; Sparrow, Janet R; Williams, David R

2011-01-01

The photoreceptor/RPE complex must maintain a delicate balance between maximizing the absorption of photons for vision and retinal image quality while simultaneously minimizing the risk of photodamage when exposed to bright light. We review the recent discovery of two new effects of light exposure on the photoreceptor/RPE complex in the context of current thinking about the causes of retinal phototoxicity. These effects are autofluorescence photobleaching in which exposure to bright light reduces lipofuscin autofluorescence and, at higher light levels, RPE disruption in which the pattern of autofluorescence is permanently altered following light exposure. Both effects occur following exposure to visible light at irradiances that were previously thought to be safe. Photopigment, retinoids involved in the visual cycle, and bisretinoids in lipofuscin have been implicated as possible photosensitizers for photochemical damage. The mechanism of RPE disruption may follow either of these paths. On the other hand, autofluorescence photobleaching is likely an indicator of photooxidation of lipofuscin. The permanent changes inherent in RPE disruption might require modification of the light safety standards. AF photobleaching recovers after several hours although the mechanisms by which this occurs are not yet clear. Understanding the mechanisms of phototoxicity is all the more important given the potential for increased susceptibility in the presence of ocular diseases that affect either the visual cycle and/or lipofuscin accumulation. In addition, knowledge of photochemical mechanisms can improve our understanding of some disease processes that may be influenced by light exposure, such as some forms of Leber’s congenital amaurosis, and aid in the development of new therapies. Such treatment prior to intentional light exposures, as in ophthalmic examinations or surgeries, could provide an effective preventative strategy. PMID:22085795

ADAPTIVE OPTICS IMAGING OF FOVEAL SPARING IN GEOGRAPHIC ATROPHY SECONDARY TO AGE-RELATED MACULAR DEGENERATION.

PubMed

Querques, Giuseppe; Kamami-Levy, Cynthia; Georges, Anouk; Pedinielli, Alexandre; Capuano, Vittorio; Blanco-Garavito, Rocio; Poulon, Fanny; Souied, Eric H

2016-02-01

To describe adaptive optics (AO) imaging of foveal sparing in geographic atrophy (GA) secondary to age-related macular degeneration. Flood-illumination AO infrared (IR) fundus images were obtained in four consecutive patients with GA using an AO retinal camera (rtx1; Imagine Eyes). Adaptive optics IR images were overlaid with confocal scanning laser ophthalmoscope near-IR autofluorescence images to allow direct correlation of en face AO features with areas of foveal sparing. Adaptive optics appearance of GA and foveal sparing, preservation of functional photoreceptors, and cone densities in areas of foveal sparing were investigated. In 5 eyes of 4 patients (all female; mean age 74.2 ± 11.9 years), a total of 5 images, sized 4° × 4°, of foveal sparing visualized on confocal scanning laser ophthalmoscope near-IR autofluorescence were investigated by AO imaging. En face AO images revealed GA as regions of inhomogeneous hyperreflectivity with irregularly dispersed hyporeflective clumps. By direct comparison with adjacent regions of GA, foveal sparing appeared as well-demarcated areas of reduced reflectivity with less hyporeflective clumps (mean 14.2 vs. 3.2; P = 0.03). Of note, in these areas, en face AO IR images revealed cone photoreceptors as hyperreflective dots over the background reflectivity (mean cone density 3,271 ± 1,109 cones per square millimeter). Microperimetry demonstrated residual function in areas of foveal sparing detected by confocal scanning laser ophthalmoscope near-IR autofluorescence. Adaptive optics allows the appreciation of differences in reflectivity between regions of GA and foveal sparing. Preservation of functional cone photoreceptors was demonstrated on en face AO IR images in areas of foveal sparing detected by confocal scanning laser ophthalmoscope near-IR autofluorescence.

Organ-Level Analysis of Idioblast Patterning in Egeria densa Planch. Leaves

PubMed Central

Hara, Takuya; Kobayashi, Emi; Ohtsubo, Kohei; Kumada, Shogo; Kanazawa, Mikako; Abe, Tomoko; Itoh, Ryuuichi D.; Fujiwara, Makoto T.

2015-01-01

Leaf tissues of plants usually contain several types of idioblasts, defined as specialized cells whose shape and contents differ from the surrounding homogeneous cells. The spatial patterning of idioblasts, particularly of trichomes and guard cells, across the leaf epidermis has received considerable attention as it offers a useful biological model for studying the intercellular regulation of cell fate and patterning. Excretory idioblasts in the leaves of the aquatic monocotyledonous plant Egeria densa produced light blue autofluorescence when irradiated with ultraviolet light. The use of epifluorescence microscopy to detect this autofluorescence provided a simple and convenient method for detecting excretory idioblasts and allowed tracking of those cells across the leaf surfaces, enabling quantitative measurement of the clustering and spacing patterns of idioblasts at the whole leaf level. Occurrence of idioblasts was coordinated along the proximal–distal, medial–lateral, and adaxial–abaxial axes, producing a recognizable consensus spatial pattern of idioblast formation among fully expanded leaves. Idioblast clusters, which comprised up to nine cells aligned along the proximal–distal axis, showed no positional bias or regularity in idioblast-forming areas when compared with singlet idioblasts. Up to 75% of idioblasts existed as clusters on every leaf side examined. The idioblast-forming areas varied between leaves, implying phenotypic plasticity. Furthermore, in young expanding leaves, autofluorescence was occasionally detected in a single giant vesicle or else in one or more small vesicles, which eventually grew to occupy a large portion of the idioblast volume as a central vacuole. Differentiation of vacuoles by accumulating the fluorescence substance might be an integral part of idioblast differentiation. Red autofluorescence from chloroplasts was not detected in idioblasts of young expanding leaves, suggesting idioblast differentiation involves an arrest in chloroplast development at a very early stage, rather than transdifferentiation of chloroplast-containing epidermal cells. PMID:25742311

Identification of protein secondary structures by laser induced autofluorescence: A study of urea and GnHCl induced protein denaturation

NASA Astrophysics Data System (ADS)

Siddaramaiah, Manjunath; Satyamoorthy, Kapaettu; Rao, Bola Sadashiva Satish; Roy, Suparna; Chandra, Subhash; Mahato, Krishna Kishore

2017-03-01

In the present study an attempt has been made to interrogate the bulk secondary structures of some selected proteins (BSA, HSA, lysozyme, trypsin and ribonuclease A) under urea and GnHCl denaturation using laser induced autofluorescence. The proteins were treated with different concentrations of urea (3 M, 6 M, 9 M) and GnHCl (2 M, 4 M, 6 M) and the corresponding steady state autofluorescence spectra were recorded at 281 nm pulsed laser excitations. The recorded fluorescence spectra of proteins were then interpreted based on the existing PDB structures of the proteins and the Trp solvent accessibility (calculated using "Scratch protein predictor" at 30% threshold). Further, the influence of rigidity and conformation of the indole ring (caused by protein secondary structures) on the intrinsic fluorescence properties of proteins were also evaluated using fluorescence of ANS-HSA complexes, CD spectroscopy as well as with trypsin digestion experiments. The outcomes obtained clearly demonstrated GnHCl preferably disrupt helix as compared to the beta β-sheets whereas, urea found was more effective in disrupting β-sheets as compared to the helices. The other way round the proteins which have shown detectable change in the intrinsic fluorescence at lower concentrations of GnHCl were rich in helices whereas, the proteins which showed detectable change in the intrinsic fluorescence at lower concentrations of urea were rich in β-sheets. Since high salt concentrations like GnHCl and urea interfere in the secondary structure analysis by circular dichroism Spectrometry, the present method of analyzing secondary structures using laser induced autofluorescence will be highly advantageous over existing tools for the same.

AN ELDERLY PATIENT WITH ACUTE TRANSIENT OUTER RETINAL DISRUPTION RESEMBLING BILATERAL MULTIPLE EVANESCENT WHITE DOT SYNDROME.

PubMed

Golshani, Cyrus; Gal-Or, Orly; Giovinazzo, Vincent; Freund, K Bailey

2017-11-07

To report an unusual case of an elderly patient with transient outer retinal disruption resembling bilateral multiple evanescent white dot syndrome. Observational case report. Fundus photographs, fluorescein angiography, standard and ultra-widefield fundus autofluorescence, and cross-sectional and en face optical coherence tomography were used to characterize and describe the clinical findings. A 67-year-old woman presented with decreased vision and floaters in her left eye. Best-corrected visual acuity was 20/20-3 in the right eye and 20/80-2 in the left eye. Funduscopic examination showed small deep white dots and foveal granularity of the left eye corresponding to hyperautofluorescent spots on fundus autofluorescence and ellipsoid zone disruption on spectral domain optical coherence tomography. The asymptomatic right eye had evidence of subretinal deposits on spectral domain optical coherence tomography but was otherwise unremarkable. At 4-week follow-up, the patient noted resolution of her symptoms in the left eye but had developed floaters and blurry vision in her right eye. The left eye showed resolving white spots and ellipsoid zone disruption. However, the right eye had new evidence of white spots corresponding to hyperautofluorescent spots on fundus autofluorescence. Spectral domain optical coherence tomography demonstrated subretinal deposits overlying areas of ellipsoid zone disruption. At 8-week follow-up, the patient was asymptomatic in both eyes with best-corrected visual acuity of 20/20 in both eyes. The hyperautofluorescent spots on ultra-widefield fundus autofluorescence had faded with restoration of ellipsoid zone disruption in both eyes and disappearance of subretinal deposits. Our case demonstrates multimodal retinal imaging findings resembling multiple evanescent white dot syndrome in an elderly patient. The bilateral presentation, presence of subretinal deposits before symptom onset, and older age of the patient were atypical features for this entity.

MULTIMODAL IMAGING ADDS NEW INSIGHTS INTO ACUTE SYPHILITIC POSTERIOR PLACOID CHORIORETINITIS.

PubMed

Tsui, Edmund; Gal-Or, Orly; Ghadiali, Quraish; Freund, K Bailey

2017-10-11

Acute syphilitic posterior placoid chorioretinitis (ASPPC) is an uncommon manifestation of ocular syphilis with distinct clinical features. We describe new multimodal imaging findings in a patient with ASPPC. Observational case report with multimodal imaging. A 44-year-old woman presented with 5 days of decreased vision in her right eye. Visual acuity was counting fingers in her right eye and 20/20 in her left eye. Funduscopic examination of the right eye showed a yellow placoid macular lesion with extension beyond the equator, which was encircled by an annular ring of outer retinal whitening. Ultra-widefield fundus autofluorescence demonstrated hyperautofluorescence corresponding to the placoid lesion. Examination of the left eye appeared unremarkable, but ultra-widefield fundus autofluorescence showed an area of hyperautofluorescence located superonasal to the optic nerve. Optical coherence tomography of the right eye demonstrated subretinal fluid and overlying disruption of the ellipsoid zone. Fluorescein angiography demonstrated early hypofluorescent and hyperfluorescent spots and late staining within the placoid lesion. Optical coherence tomography angiography showed several areas of decreased flow signal within the placoid lesion at the level of the choriocapillaris. Laboratory testing revealed a rapid plasma reagin titer of 1:1,024. Two months after treatment with intravenous penicillin G, visual acuity had improved to 20/25 in her right eye, and optical coherence tomography showed partial restoration of the ellipsoid zone. The annular ring resolved with near normalization of fundus autofluorescence and optical coherence tomography angiography demonstrated resolution of flow. Multimodal imaging provides further insight into the pathogenesis of ASPPC. Ultra-widefield fundus autofluorescence may show evidence of ellipsoid zone disruption in areas that clinically appear normal. Flow voids within the choriocapillaris in ASPPC appear to resolve with appropriate treatment, a finding that suggests a transient disruption of choriocapillaris flow in ASPPC.

Quantitative imaging of electron transfer flavoprotein autofluorescence reveals the dynamics of lipid partitioning in living pancreatic islets.

PubMed

Lam, Alan K; Silva, Pamuditha N; Altamentova, Svetlana M; Rocheleau, Jonathan V

2012-08-01

Pancreatic islet β-cells metabolically sense nutrients to maintain blood glucose homeostasis through the regulated secretion of insulin. Long-term exposure to a mixed supply of excess glucose and fatty acids induces β-cell dysfunction and type II diabetes in a process termed glucolipotoxicity. Despite a number of documented mechanisms for glucolipotoxicity, the interplay between glucose and fatty acid oxidation in islets remains debated. Here, we develop confocal imaging of electron transfer flavoprotein (ETF) autofluorescence to reveal the dynamics of fatty acid oxidation in living pancreatic islets. This method further integrates microfluidic devices to hold the islets stationary in flow, and thus achieve ETF imaging in the β-cells with high spatial and temporal resolution. Our data first confirm that ETF autofluorescence reflects electron transport chain (ETC) activity downstream of Complex I, consistent with a response directly related to fatty acid metabolism. Together with two-photon imaging of NAD(P)H and confocal imaging of lipoamide dehydrogenase (LipDH) autofluorescence, we show that the ETC predominantly draws electrons from LipDH/NADH-dependent Complex I rather than from ETF/FADH(2)-dependent ETF:CoQ oxidoreductase (ETF-QO). Islets stimulated with palmitate also show increased ETF redox state that is dose-dependently diminished by glucose (>10 mM). Furthermore, stimulation with a glucose bolus causes a two-tier drop in the ETF redox state at ∼5 and ∼20 min, suggesting glucose metabolism immediately increases ETC activity and later decreases fatty acid oxidation. Our results demonstrate the utility of ETF imaging in characterizing fatty acid-induced redox responses with high subcellular and temporal resolution. Our results further demonstrate a dominant role of glucose metabolism over fatty acid oxidation in β-cells even when presented with a mixed nutrient condition associated with glucolipotoxicity.

The use of light-based (optical) detection systems as adjuncts in the detection of oral cancer and oral potentially malignant disorders: a systematic review.

PubMed

Rashid, A; Warnakulasuriya, S

2015-05-01

In recent decades, optical techniques utilising the principles of chemiluminescence and tissue autofluorescence have emerged to facilitate the early detection of any oral mucosal changes suspicious of cancer. To evaluate the effectiveness of devices that utilise the principles of chemiluminescence and tissue autofluorescence as adjuncts in the detection of oral cancer and oral potentially malignant disorders (OPMDs). A systematic review of the published literature to evaluate the effectiveness of the ViziLite(®) and ViziLite(®) Plus with toluidine blue, MicroLux™/DL and the VELscope™ as aids in the detection of oral cancer and OPMDs. Twenty-five primary studies published between 2004 and 2013 satisfied our criteria for selection - 13 utilised chemiluminescence and 12 tissue autofluorescence. Some had utilised both study methods on the same population. Chemiluminescence shows good sensitivity at detecting any OPMDs and oral cancer. However, it preferentially detects leukoplakia and may fail to spot red patches. The additive use of toluidine blue may improve specificity. Tissue autofluorescence is sensitive at detecting white, red and white and red patches, and the area of fluorescence visualisation loss (FVL) often extends beyond the clinically visible lesion. However, in addition to OPMDs, VELScope may detect erythematous lesions of benign inflammation resulting in false-positive test results. There is limited evidence for their use in primary care, and these tools are better suited to specialist clinics in which there is a higher prevalence of disease and where experienced clinicians may better discriminate between benign and malignant lesions. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Skin autofluorescence reflects individual seasonal UV exposure, skin photodamage and skin cancer development in organ transplant recipients.

PubMed

Togsverd-Bo, Katrine; Philipsen, Peter Alshede; Hædersdal, Merete; Wulf, Hans Christian Olsen

2018-01-01

Ultraviolet radiation (UVR)-induced skin cancers varies among organ transplant recipients (OTRs). To improve individual risk assessment of skin cancer, objectively quantified skin photodamage is needed. We measured personal UVR-exposure dose in OTRs and assessed the relation between individual UVR exposure, skin cancer and objectively measured photodamage in terms of skin autofluorescence, pigmentation, and black light-evaluated solar lentigines. Danish OTRs with (n=15) and without a history of skin cancer (n=15) kept sun diaries from May to September and wore personal dosimeters recording time-stamped UVR doses in standard erythema doses (SED). Photodamage was quantified as skin autofluorescence with excitation at 370nm (F370) and 430nm (F430), skin pigmentation (pigment protection factor, PPF), and black light-evaluated solar lentigines. OTRs with skin cancer received a higher UVR dose than OTRs without skin cancer (median 116 SED vs. 67 SED, p=0.07) and UVR exposure doses were correlated with increased PPF (p=0.052) and F370 on the shoulder (F370 shoulder ) (p=0.04). We found that skin cancer was associated with F370 shoulder (OR 10.53, CI 3.3-31,938; p=0.018) and time since transplantation (OR 1.34, CI 0.95-1.91, p=0.097). A cut-off at 7.2 arbitrary units, 89% of OTRs with skin cancer had F370 shoulder values above 7.2 arbitrary units and F370 shoulder was additionally related to patient age (p=0.09) and black light-evaluated solar lentigines (p=0.04). F370 autofluorescence indicates objectively measured photodamage and may be used for individual risk assessment of skin cancer development in OTRs. Copyright © 2017. Published by Elsevier B.V.

Point-of-Care Autofluorescence Imaging for Real-Time Sampling and Treatment Guidance of Bioburden in Chronic Wounds: First-in-Human Results

PubMed Central

DaCosta, Ralph S.; Kulbatski, Iris; Lindvere-Teene, Liis; Starr, Danielle; Blackmore, Kristina; Silver, Jason I.; Opoku, Julie; Wu, Yichao Charlie; Medeiros, Philip J.; Xu, Wei; Xu, Lizhen; Wilson, Brian C.; Rosen, Cheryl; Linden, Ron

2015-01-01

Background Traditionally, chronic wound infection is diagnosed by visual inspection under white light and microbiological sampling, which are subjective and suboptimal, respectively, thereby delaying diagnosis and treatment. To address this, we developed a novel handheld, fluorescence imaging device (PRODIGI) that enables non-contact, real-time, high-resolution visualization and differentiation of key pathogenic bacteria through their endogenous autofluorescence, as well as connective tissues in wounds. Methods and Findings This was a two-part Phase I, single center, non-randomized trial of chronic wound patients (male and female, ≥18 years; UHN REB #09-0015-A for part 1; UHN REB #12-5003 for part 2; clinicaltrials.gov Identifier: NCT01378728 for part 1 and NCT01651845 for part 2). Part 1 (28 patients; 54% diabetic foot ulcers, 46% non-diabetic wounds) established the feasibility of autofluorescence imaging to accurately guide wound sampling, validated against blinded, gold standard swab-based microbiology. Part 2 (12 patients; 83.3% diabetic foot ulcers, 16.7% non-diabetic wounds) established the feasibility of autofluorescence imaging to guide wound treatment and quantitatively assess treatment response. We showed that PRODIGI can be used to guide and improve microbiological sampling and debridement of wounds in situ, enabling diagnosis, treatment guidance and response assessment in patients with chronic wounds. PRODIGI is safe, easy to use and integrates into the clinical workflow. Clinically significant bacterial burden can be detected in seconds, quantitatively tracked over days-to-months and their biodistribution mapped within the wound bed, periphery, and other remote areas. Conclusions PRODIGI represents a technological advancement in wound sampling and treatment guidance for clinical wound care at the point-of-care. Trial Registration ClinicalTrials.gov NCT01651845; ClinicalTrials.gov NCT01378728 PMID:25790480

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brasch, R.C.; Wesbey, G.E.; Gooding, C.A.

Tissue deposits of hemosiderin, a paramagnetic iron-protein complex, resulted in marked abnormalities of magnetic resonance (MR) spin-echo signal intensity within the viscera of three children with transfusional hemosiderosis and thalassemia major. In all patients the liver and bone marrow demonstrated abnormally low spin-echo intensities and the kidneys and muscles had abnormally high intensities. These observations correlate with in vitro MR observation of ferric (Fe/sup +3/) solutions, in which concentrations of ferric salts greater than 20 mmol yielded higher intensities than did water alone. MR imaging is sensitive to the tissue deposition of hemosiderin, and MR intensity appears to provide amore » rough measure of the amount of iron deposited.« less

A Decline in Intraoperative Renal Near-Infrared Spectroscopy Is Associated With Adverse Outcomes in Children Following Cardiac Surgery.

PubMed

Gist, Katja M; Kaufman, Jonathan; da Cruz, Eduardo M; Friesen, Robert H; Crumback, Sheri L; Linders, Megan; Edelstein, Charles; Altmann, Christopher; Palmer, Claire; Jalal, Diana; Faubel, Sarah

2016-04-01

Renal near-infrared spectroscopy is known to be predictive of acute kidney injury in children following cardiac surgery using a series of complex equations and area under the curve. This study was performed to determine if a greater than or equal to 20% reduction in renal near-infrared spectroscopy for 20 consecutive minutes intraoperatively or within the first 24 postoperative hours is associated with 1) acute kidney injury, 2) increased acute kidney injury biomarkers, or 3) other adverse clinical outcomes in children following cardiac surgery. Prospective single center observational study. Pediatric cardiac ICU. Children less than or equal to age 4 years who underwent cardiac surgery with the use of cardiopulmonary bypass during the study period (June 2011-July 2012). None. A reduction in near-infrared spectroscopy was not associated with acute kidney injury. Nine of 12 patients (75%) with a reduction in renal near-infrared spectroscopy did not develop acute kidney injury. The remaining three patients had mild acute kidney injury (pediatric Risk, Injury, Failure, Loss, End stage-Risk). A reduction in renal near-infrared spectroscopy was associated with the following adverse clinical outcomes: 1) a longer duration of mechanical ventilation (p = 0.05), 2) longer intensive care length of stay (p = 0.05), and 3) longer hospital length of stay (p < 0.01). A decline in renal near-infrared spectroscopy in combination with an increase in serum interleukin-6 and serum interleukin-8 was associated with a longer intensive care length of stay, and the addition of urine interleukin-18 to this was associated with a longer hospital length of stay. In this cohort, the rate of acute kidney injury was much lower than anticipated thereby limiting the evaluation of a reduction in renal near-infrared spectroscopy as a predictor of acute kidney injury. A greater than or equal to 20% reduction in renal near-infrared spectroscopy was significantly associated with adverse outcomes in children following cardiac surgery. The addition of specific biomarkers to the model was predictive of worse outcomes in these patients. Thus, real-time evaluation of renal near-infrared spectroscopy using the specific levels of change of a 20% reduction for 20 minutes may be useful in predicting prolonged mechanical ventilation and other adverse outcomes in children undergoing cardiac surgery.

In situ hybridization protocol for enhanced detection of gene expression in the planarian Schmidtea mediterranea

PubMed Central

2013-01-01

Background The freshwater planarian Schmidtea mediterranea has emerged as a powerful model for studies of regenerative, stem cell, and germ cell biology. Whole-mount in situ hybridization (WISH) and whole-mount fluorescent in situ hybridization (FISH) are critical methods for determining gene expression patterns in planarians. While expression patterns for a number of genes have been elucidated using established protocols, determining the expression patterns for particularly low-abundance transcripts remains a challenge. Results We show here that a short bleaching step in formamide dramatically enhances signal intensity of WISH and FISH. To further improve signal sensitivity we optimized blocking conditions for multiple anti-hapten antibodies, developed a copper sulfate quenching step that virtually eliminates autofluorescence, and enhanced signal intensity through iterative rounds of tyramide signal amplification. For FISH on regenerating planarians, we employed a heat-induced antigen retrieval step that provides a better balance between permeabilization of mature tissues and preservation of regenerating tissues. We also show that azide most effectively quenches peroxidase activity between rounds of development for multicolor FISH experiments. Finally, we apply these modifications to elucidate the expression patterns of a few low-abundance transcripts. Conclusion The modifications we present here provide significant improvements in signal intensity and signal sensitivity for WISH and FISH in planarians. Additionally, these modifications might be of widespread utility for whole-mount FISH in other model organisms. PMID:23497040

Visualization of human heart conduction system by means of fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Venius, Jonas; Bagdonas, Saulius; Žurauskas, Edvardas; Rotomskis, Ricardas

2011-10-01

The conduction system of the heart is a specific muscular tissue, where a heartbeat signal originates and initiates the depolarization of the ventricles. The muscular origin makes it complicated to distinguish the conduction system from the surrounding tissues. A surgical intervention can lead to the accidental harm of the conduction system, which may eventually result in a dangerous obstruction of the heart functionality. Therefore, there is an immense necessity for developing a helpful method to visualize the conduction system during the operation time. The specimens for the spectroscopic studies were taken from nine diverse human hearts. The localization of distinct types of the tissue was preliminary marked by the pathologist and approved histologically after the spectral measurements. Variations in intensity, as well as in shape, were detected in autofluorescence spectra of different heart tissues. The most distinct differences were observed between the heart conduction system and the surrounding tissues under 330 and 380 nm excitation. The spectral region around 460 nm appeared to be the most suitable for an unambiguous differentiation of the human conduction system avoiding the absorption peak of blood. The visualization method, based on the intensity ratios calculated for two excitation wavelengths, was also demonstrated.

Vital-dye-enhanced multimodal imaging of neoplastic progression in a mouse model of oral carcinogenesis

NASA Astrophysics Data System (ADS)

Hellebust, Anne; Rosbach, Kelsey; Wu, Jessica Keren; Nguyen, Jennifer; Gillenwater, Ann; Vigneswaran, Nadarajah; Richards-Kortum, Rebecca

2013-12-01

In this longitudinal study, a mouse model of 4-nitroquinoline 1-oxide chemically induced tongue carcinogenesis was used to assess the ability of optical imaging with exogenous and endogenous contrast to detect neoplastic lesions in a heterogeneous mucosal surface. Widefield autofluorescence and fluorescence images of intact 2-NBDG-stained and proflavine-stained tissues were acquired at multiple time points in the carcinogenesis process. Confocal fluorescence images of transverse fresh tissue slices from the same specimens were acquired to investigate how changes in tissue microarchitecture affect widefield fluorescence images of intact tissue. Widefield images were analyzed to develop and evaluate an algorithm to delineate areas of dysplasia and cancer. A classification algorithm for the presence of neoplasia based on the mean fluorescence intensity of 2-NBDG staining and the standard deviation of the fluorescence intensity of proflavine staining was found to separate moderate dysplasia, severe dysplasia, and cancer from non-neoplastic regions of interest with 91% sensitivity and specificity. Results suggest this combination of noninvasive optical imaging modalities can be used in vivo to discriminate non-neoplastic from neoplastic tissue in this model with the potential to translate this technology to the clinic.

Laser-induced autofluorescence-based objective evaluation of burn tissue repair in mice.

PubMed

Rathnakar, Bharath; Rao, Bola Sadashiva Satish; Prabhu, Vijendra; Chandra, Subhash; Mahato, Krishna Kishore

2018-05-01

Management of burn injuries are a growing concern, especially in determining the progression of healing. Several techniques are being practiced in clinics and have been considered all-time standard approaches to determine pre- and post-treatment outcomes of a healthy healing. However, these kinds of methods involve repeated biopsies and thereby hindering tissue repair. In view of this, our perspective was to develop a non-invasive tool in an attempt to provide a solution to determine the progression of healing, in vivo. Hence, the present study was designed to investigate the ability of laser-induced fluorescence (LIF) to monitor the variations in collagen intensity at various time points (0, 2, 6, 12, 18, 24, and 30 days) during burn tissue repair in mice, post low-power laser therapy (LPLT). The spectral findings demonstrated a significant change in collagen intensity as observed on day 24 (p < 0.05) and 30 (p < 0.01), when treated with LPLT (830 nm 3 J/cm 2 ) as compared to untreated control. From the observation, it was evident that the LIF could objectively monitor the progression of burn tissue repair in vivo.

INTENSIVE OBSERVATION OF TOXIC SIDE EFFECTS AFTER SEVERAL-YEAR OF CYCLOSPORIN TREATMENT IN KIDNEY TRANSPLANT PATIENT

PubMed Central

Ašćerić, Mensura; Avdić, Sevleta; Nukić, Sabrija; Vrabac-Mujčinagić, Muamera

2007-01-01

In this work we are going to show results of intensive observation of adverse reactions of cyclosporine therapy during 18 months. The research was applied on 30 patients with kidney transplant. The medium time of kidney transplant survival was 9,7±2,3 years, with time span of 6 to 15 years. All the patients were subjects to several years’ cyclosporine treatment, which was applied on a daily basis with a dosage of 2 to 5 mg/kg of body weight. The concentration of cyclosporine in blood was measured once a month. The concentration of cyclosporine in blood in 19 patients was in referent values of 122,50 nag/ml up to 280,50 nag/ml of blood. In 4 of the patients the concentration was heightened up to 370 to 538 nag/ml (χ=766,37 nag/ml), and in 7 patients cyclosporine was below normal dosage down to 30,78 to 96,30 nag/ml in blood (x=77,12 nag/ml). We noticed these toxic side effects: increased values of systolic and diastolic arterial blood pressure in 5 patients, neurotoxic tremor effects in 4 patients, hyper-plasia gingival and hirsute in 1 patient each.

Photonic Crystal Enhanced Fluorescence for Early Breast Cancer Biomarker Detection

PubMed Central

Cunningham, Brian T.; Zangar, Richard C.

2013-01-01

Photonic crystal surfaces offer a compelling platform for improving the sensitivity of surface-based fluorescent assays used in disease diagnostics. Through the complementary processes of photonic crystal enhanced excitation and enhanced extraction, a periodic dielectric-based nanostructured surface can simultaneously increase the electric field intensity experienced by surface-bound fluorophores and increase the collection efficiency of emitted fluorescent photons. Through the ability to inexpensively fabricate photonic crystal surfaces over substantial surface areas, they are amenable to single-use applications in biological sensing, such as disease biomarker detection in serum. In this review, we will describe the motivation for implementing high-sensitivity, multiplexed biomarker detection in the context of breast cancer diagnosis. We will summarize recent efforts to improve the detection limits of such assays though the use of photonic crystal surfaces. Reduction of detection limits is driven by low autofluorescent substrates for photonic crystal fabrication, and detection instruments that take advantage of their unique features. PMID:22736539