Investigation of the phenomenon of photobleaching and evaluation of the effectiveness of treatment using a led photodynamic therapy device on optical phantoms

The mortality rate from various oncological diseases remains consistently extremely high, even in spite of recent breakthrough discoveries in the field of cancer therapy [1-3]. One of the most promising cancer treatments is photodynamic therapy (PDT) combined with fluorescence diagnostics (FD) [4, 5]. This study aims to evaluate the efficiency of the PDT procedure using an experimental LED device for photodynamic therapy and fluorescence diagnostics of neoplasms by the level of photobleaching of the photosensitizer protoporphyrin IX (PPIX) in optical phantoms of the skin. The results of spectral measurements showed that the LEDs is able to effectively induce oxidative stress in cancer cells, and due to the presence of a video system, it becomes possible to register the level of tissue fluorescence.

Topical Gadobutrol Application Causes Fluorescence Intensity Change in RFP-expressing Tumor-Bearing Mice

Optical clearing (OC) allows one to observe tissue structures and metabolic processes occurring in opaque tissues at the depths significantly exceeding the depths that can be reached without OC. Recently, we have shown that gadobutrol is a promising agent for OC of tissues in vivo. The aim of this study was to investigate the effect of time-dependence optical clearing caused by gadobutrol on intensity of fluorescent protein constitutively expressed in subcutaneous tumors in vivo. The measurements were performed in nu/nu mice bearing HEp-2 tumors expressing the red fluorescent protein TagRFP. Gadobutrol was used directly at concentrations 1.0 M aqueous solution or as a 0.7 M aqueous solution containing 5% dimethyl sulfoxide (DMSO). Gadobutrol was applied topically onto the skin above the tumors for 15 min. Tissue fluorescence was measured by using in vivo planar imaging technique. It was shown that the fluorescence intensity of tumors increased by 1.1–1.5 times in different animals under the influence of gadobutrol. The increase in intensity was more pronounced in the case of 0.7 M gadobutrol supplemented with DMSO. Apparently, the observed difference of penetration depths was due to the presence of DMSO in 0.7 M gadobutrol mixture.

Molecular and Metabolic Mechanisms Underlying Selective 5-Aminolevulinic Acid-Induced Fluorescence in Gliomas

5-aminolevulinic acid (5-ALA) is a porphyrin precursor in the heme synthesis pathway. When supplied exogenously, certain cancers consume 5-ALA and convert it to the fluorogenic metabolite protoporphyrin IX (PpIX), causing tumor-specific tissue fluorescence. Preoperative administration of 5-ALA is used to aid neurosurgical resection of high-grade gliomas such as glioblastoma, allowing for increased extent of resection and progression free survival for these patients. A subset of gliomas, especially low-grade tumors, do not accumulate PpIX intracellularly or readily fluoresce upon 5-ALA administration, making gross total resection difficult to achieve in diffuse lesions. We review existing literature on 5-ALA metabolism and PpIX accumulation to explore potential mechanisms of 5-ALA-induced glioma tissue fluorescence. Targeting the heme synthesis pathway and understanding its dysregulation in malignant tissues could aid the development of adjunct therapies to increase intraoperative fluorescence after 5-ALA treatment.

Identification of Hub Genes Associated with the Development of Acute Kidney Injury by Weighted Gene Co-Expression Network Analysis

<b><i>Background:</i></b> Acute kidney injury (AKI) is a severe clinical syndrome, causing a profound medical and socioeconomic burden worldwide. This study aimed to explore underlying molecular targets related to the progression of AKI. <b><i>Methods:</i></b> A public database originated from the NCBI GEO database (serial number: GSE121190) and a well-established and unbiased method of weighted gene co-expression network analysis (WGCNA) to identify hub genes and potential pathways were used. Furthermore, the unbiased hub genes were validated in 2 classic models of AKI in a rodent model: chemically established AKI by cisplatin- and ischemia reperfusion-induced AKI. <b><i>Results:</i></b> A total of 17 modules were finally obtained by the unbiased method of WGCNA, where the genes in turquoise module displayed strong correlation with the development of AKI. In addition, the results of gene ontology revealed that the genes in turquoise module were involved in renal injury and renal fibrosis. Thus, the hub genes were further validated by experimental methods and primarily obtained Rplp1 and Lgals1 as key candidate genes related to the progression of AKI by the advantage of quantitative PCR, Western blotting, and in situ tissue fluorescence. Importantly, the expression of Rplp1 and Lgals1 at the protein level showed positive correlation with renal function, including serum Cr and BUN. <b><i>Conclusions:</i></b> By the advantage of unbiased bioinformatic method and consequent experimental verification, this study lays the foundation basis for the pathogenesis and therapeutic agent development of AKI.

Bi2O3 boosts Brightness, Biocompatibility and Stability of Mn-doped Ba3(VO4)2 as NIR-II Contrast Agent

Deep-tissue fluorescence imaging remains a major challenge as there is limited availability of bright biocompatible materials with high photo- and chemical stability. Contrast agents with emission wavelengths above 1000 nm...

New fluorescent imaging technics in gastrology

Introduction. There is a need to develop a new imaging technique in medicine. Gastroenterology is the branch of medicine focused on the digestive system and its disorders therefore for this branch is needed to detect all problems affecting the gastrointestinal tract. Aim. The aim of this article is to complete discuss the possibility of the new fluorescent imaging technics in gastrology to use innovative screening to identify individuals at an early stage. Material and methods. We discuss here imaging techniques such as include x-rays, computed tomography, scans, and magnetic resonance imaging in gastrology. Spectroscopy is the study of the formation and interpretation of spectra resulting from the interaction of all types of radiation on matter understood as a community of atoms and molecules. Various spectroscopic techniques are obtained by combining different types of radiation with different ways of its interaction with the test sample. They provide the opportunity to obtain detailed information about the tested substance – from its atomic composition, through its chemical structure, to its surface structure. Analysis of the literatue. The tissue fluorescence spectrum can be obtained by: (1) autofluorescence, or natural or primary fluorescence, i.e. by direct irradiation of the tissue with laser radiation (laser-induced fluorescence – LIF) and (2) photodynamic diagnosis (PDD), where spectrum analysis is preceded by systemic or local administration of the photosensitizer. Conclusion. The use of fluorescence imaging in colon cancer patient has potential to improve quality of treatment and diagnosis.