Retinal image enhancement and analysis for diabetic retinopathy assessment
Ahmad Fadzil Mohamad Hani, Dileep Kumar in Optical Imaging for Biomedical and Clinical Applications, 2017
The enhancement of contrast succeeded by RETICA is of great importance to minimize the utilization of invasive operations such as the FFA that has the best emergence of retinal veins. Nevertheless, due to its invasiveness by injecting contrasting agent into the veins, this method can also cause physiological issues such as nausea, spewing and discombobulation [26]. The least favourable case of negative reactions after fluorescein injection may be fatal anaphylactic shock, which can ultimately lead to death [66]. Furthermore, RETICA can be implemented as part of computerised medical diagnosis system to process the image prior to segmenting and analysing the results. The use of RETICA as an image-enhancement method is advantageous to increase sensitivity, specificity and accuracy of the system in diagnosing retina-related eye sicknesses, for example, DR.
Capillaroscopy and Fluorescence Videomicroscopy
Enzo Berardesca, Peter Elsner, Klaus-P. Wilhelm, Howard I. Maibach in Bioengineering of the Skin: Methods and Instrumentation, 2020
By means of intravital microscopy with epi-illumination cutaneous nutritive capillaries can be examined in vivo with magnification from 10 to 80 × (e.g., Wild Leitz M 3 stereomicroscope, Leica Vertrieb GmbH, D-64625 Benzheim). Each dermal papilla contains one to three of these superficial capillaries, which are responsible for nutrition of the skin. Most reliable information about nutritional cutaneous blood flow can be achieved only by capillaroscopic methods (capillaroscopy). If Na-fluorescein is injected intravenously during investigation, homogeneity of nutritive skin perfusion as well as transcapillary and interstitial diffusion properties also can be assessed.1 The so-called fluorescence videomicroscopy covers a risk of anaphlactic or anaphylactoid reaction. Therefore, all methods of resuscitation must be available during the whole period of examination.
Management of Acute Intestinal Ischaemia
Peter Sagar, Andrew G. Hill, Charles H. Knowles, Stefan Post, Willem A. Bemelman, Patricia L. Roberts, Susan Galandiuk, John R.T. Monson, Michael R.B. Keighley, Norman S. Williams in Keighley & Williams’ Surgery of the Anus, Rectum and Colon, 2019
Fluorescence studies, using sodium fluorescein or indocyanine green, are additional studies that can help assess intestinal viability. Sodium fluorescein is injected intravenously, and the intestine is subsequently examined using ultraviolet light. This study can be performed during laparotomy by turning off the operating room lights and shining a Wood’s lamp over the intestine or during laparoscopy using a light source that produces ultraviolet light. Qualitative and quantitative assessment of fluorescence can be made. Although quantitative measurements appear to be more accurate, the overall accuracy of fluorescein studies is debated.19 One major disadvantage to sodium fluorescein use is that the substance lingers in the tissue, limiting the ability to perform repeated studies. Intravenous indocyanine green (ICG) with near-infrared (NIR) angiography is a newer technique to examine intestinal perfusion. ICG is a non-toxic compound that circulates in the blood, bound to plasma proteins, and it is quickly metabolised by the liver and excreted in bile. It maximally absorbs 800 nm wavelength light, allowing it to be detected with NIR cameras.20 The technique of ICG angiography is similar to that of fluorescein angiography. ICG is administered intravenously, and the tissue of interest is visualised with an NIR camera. Perfused tissue will light up in green, whilst ischaemic tissue will remain dark. Although the use of ICG angiography has been only minimally studied in mesenteric ischaemia,21 it has been shown to be effective in colorectal surgery at visualising perfusion and potentially reducing anastomotic leak rates.22,23
Research progress of novel inorganic nanometre materials carriers in nanomedicine for cancer diagnosis and treatment
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Jiasheng Xu, Kaili Liao, Huixia Jiang, Weimin Zhou
In 2015, Li et al. [52] synthesized a fluorescence-labelled hydroxyapatite nanoparticle LA-BSA-CBA-MHAPNs. Among them, fluorescein isothiocyanate is used as a fluorescent marker for fluorescence imaging. As shown in Figure 13, lactose-linked bovine serum albumin (LA-BSA) acts as a cap and CBA acts as a linker. When the pH was 7.4, the release rate of the drug was low. When the pH was around 5.0, the release of the mesopores of the carrier was opened with the breaking of the cyclic ester bond between LA-BSA and MHAPNs, and the drug release rate was significantly increased. Therefore, the excellent performance of the pH response enhances the enrichment of nanomedicines at the site of the lesion, and the material releases anticancer drugs through acid explanation, effectively inhibits the proliferation of cancer cells and promotes the apoptosis of cancer cells.
Physicochemical properties and micro-interaction between micro-nanoparticles and anterior corneal multilayer biological interface film for improving drug delivery efficacy: the transformation of tear film turnover mode
Published in Drug Delivery, 2023
Huamei Li, Fuda Dai, Hanyu Liu, Qi Tao, Jie Hu, Yangrong Zhang, Zhenping Xiao, Ilva D. Rupenthal, Huihui Li, Fan Yang, Wei Li, Huaqing Lin, Dongzhi Hou
Sodium fluorescein was loaded into the preparations to observe its retention time on the ocular surface. As shown in Figure 3(A), a high amount of fluorescence was observed on the ocular surface within 10 s after administration of the BHC solution. However, due to blinking and nasolacrimal drainage, the majority of the fluorescence disappeared from the ocular surface within 3 min but was found in the rabbit nose. After 16 min, no fluorescence was visible on the ocular surface in the BHC solution group. However, higher fluorescence was still observed after 20 min for the MT-BHC MPs and MT-BHC SLNs groups. No fluorescence signal was detected in the MT-BHC SLNs after 45 min, while a signal was still visible for the MT-BHC MPs group until 135 min. This suggests that the retention time of MT-BHC MPs and MT-BHC SLNs was significantly longer than that of the BHC solution. To explore the reasons why the particle preparations significantly prolong the precorneal retention, we first studied the following physicochemical properties of the three preparations.
Cubic and hexagonal liquid crystal gels for ocular delivery with enhanced effect of pilocarpine nitrate on anti-glaucoma treatment
Published in Drug Delivery, 2019
Wang Xingqi, Zhang Yong, Li Xing, Wang Yang, Huang Jie, Hu Rongfeng, Gui Shuangying, Chu Xiaoqin
In order to estimate the intraocular residence time in vivo, sodium fluorescein-loaded H2 gel and Q2 gel were applied to the lower fornix of the rabbit eye, and photos were recorded at a predetermined time point (Figure 3). In this experiment, sodium fluorescein-loaded solution was used to represent eye drops as a reference. It could be found that the quite strong signal intensity was observed for LC gels, and most of this signal was distributed in the lower conjunctival sac even more than 3 h, i.e. the site of administration, compared with eye drops. Obviously, the rabbit eye which received eye drops did not show a strong signal intensity and rapidly cleared after 10 min of administration, indicating that eye drops had a short retention time on the ocular surface. It was indicated that LC gels had well bioadhesion property to overcome blinking and flushing of tears, which may be due to the interaction between biofilm-like LC gels and mucin in corneal epithelium. These results were in line with our rheological analysis.
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