Fluorescence spectroscopy and imaging studies of functionally different human heart tissues

Rhythmical contraction of the heart is controlled by the cardiac conduction system (CCS). However, this highly important system visually could not be distinguished from the surrounding heart tissues – myocardium (MC) and connective tissue (CT); therefore during surgical procedures CCS could be damaged. The reliable method for CCS identification either in vivo or ex vivo does not exist therefore there is a definite need for developing a CCS imaging method. Fluorescence spectroscopy studies of cardiac tissues revealed, that most distinct spectral differences between CCS and the surrounding tissues were observed in 400 nm – 550 nm region under excitation from 330 nm – 380 nm region. The visualization method, based on the intensity ratios calculated for two excitation wavelengths, has been established. The calculated ratio R = I(330)/I(380) is different for CCS, CT and MC tissues, therefore the method may be used for identification of CCS. Time resolved fluorescence spectroscopy revealed no significant difference in composition and lifetimes between CCS and MC. On the other hand, the lifetimes and the relative spectral composition of CT differed significantly from those of CCS. Reflection confocal microscopy allows visualizing MC, CT, Purkinje cells and CCS bundles because of different reflection properties of tissue components and their specific distribution inside the tissue. The results of in vivo performed procedure revealed, that the distribution of fluorescence intensities are similar to those, observed during ex vivo experiments, therefore the established CCS identification method, based on intensity ratios, is suitable for cardiac investigations in vivo

Funkciškai besiskiriančių žmogaus širdies audinių fluorescenciniai tyrimai ir vaizdinimas

Rhythmical contraction of the heart is controlled by the cardiac conduction system (CCS). However, this highly important system visually could not be distinguished from the surrounding heart tissues – myocardium (MC) and connective tissue (CT); therefore during surgical procedures CCS could be damaged. The reliable method for CCS identification either in vivo or ex vivo does not exist therefore there is a definite need for developing a CCS imaging method. Fluorescence spectroscopy studies of cardiac tissues revealed, that most distinct spectral differences between CCS and the surrounding tissues were observed in 400 nm – 550 nm region under excitation from 330 nm – 380 nm region. The visualization method, based on the intensity ratios calculated for two excitation wavelengths, has been established. The calculated ratio R = I(330)/I(380) is different for CCS, CT and MC tissues, therefore the method may be used for identification of CCS. Time resolved fluorescence spectroscopy revealed no significant difference in composition and lifetimes between CCS and MC. On the other hand, the lifetimes and the relative spectral composition of CT differed significantly from those of CCS. Reflection confocal microscopy allows visualizing MC, CT, Purkinje cells and CCS bundles because of different reflection properties of tissue components and their specific distribution inside the tissue. The results of in vivo performed procedure revealed, that the distribution of fluorescence intensities are similar to those, observed during ex vivo experiments, therefore the established CCS identification method, based on intensity ratios, is suitable for cardiac investigations in vivo

5-Aminolevulinic acid-based fluorescence diagnostics of cervical preinvasive changes

The purpose of this article is to review the diagnostic possibilities of 5-aminolevulinic acid (5-ALA)-based fluorescence diagnosis of preinvasive cervical changes. Reviewed papers were selected from the PubMed database with keywords combining the terms individual cervical neoplasia and fluorescence diagnostics. The regular colposcopy procedure lacks specificity; therefore, new methods are continually sought for superior diagnosis of cervical pathology. 5-ALA-based fluorescence diagnostics is under investigation as an up-to-date diagnostic technique for cervical intraepithelial neoplasia (CIN). This method is grounded on the topical or systemic application of 5-ALA, which induces excess production of the endogenous photosensitizer protoporphyrin IX (PpIX) in tissues where carcinogenesis has begun. The conversion of PpIX to the heme is less efficient in tumors; therefore, higher amounts of PpIX tend to accumulate in premalignant and malignant tissues. Illumination with light of the appropriate wavelength initiates excitation of PpIX fluorescence, which in turn helps to localize PpIX-rich areas and identify potentially malignant tissues. A number of investigations suggest that because of its high selectivity for tumors and low toxicity to healthy tissues, 5-ALA-based diagnosis seems a promising tool for the noninvasive identification of cervical intraepithelial neoplasia

A Pilot Study of Safer Radiation Dosage to the Heart and Its Subregions

Background and Objectives: The real impact of ionizing radiation on the heart and poorer overall survival for patients with non small cell lung cancer (NSCLC) remains unclear. This study aims to determine the safe dose constraints to the heart’s subregions that could prevent patients’ early non-cancerous death and improve their quality of life. Methods and Materials: A retrospective cohort study was performed containing 51 consecutive patients diagnosed with stage III NSCLC and treated using 3D, Intensity-modulated radiation therapy (IMRT), and Volumetric modulated arc therapy (VMAT) radiotherapy. For a dosimetric analysis, these structures were chosen: heart, heart base (HB), and region of great blood vessels (GBV). Dose–volume histograms (DVH) were recorded for all mentioned structures. Maximum and mean doses to the heart, HB, the muscle mass of the HB, and GBV were obtained. V10–V60 (%) parameters were calculated from the DVH. After performed statistical analysis, logistic regression models were created, and critical doses calculated. Results: The critical dose for developing a fatal endpoint for HB was 30.5 Gy, while for GBV, it was 46.3 Gy. Increasing the average dose to the HB or GBV by 1 Gy from the critical dose further increases the possibility of early death by 22.0% and 15.8%, respectively. Conclusions: We suggest that the non-canonical sub-regions of the heart (HB and GBV) should be considered during the planning stage. Additional constraints of the heart subregions should be chosen accordingly, and we propose that the mean doses to these regions be 30.5 Gy and 46.3 Gy, respectively, or less. Extrapolated DVH curves for both regions may be used during the planning stage with care

Širdies audinių ekstraktų tyrimas spektroskopijos metodais

The conduction system of the heart (HCS) is a type of muscular tissue which generates and transmits bioelectrical impulses. During surgical operations it is possible to harm HCS, since the common origin makes it hardly discernible for an unaided eye in the surroundings of ordinary myocardium (MC) or endocardium. The aim of this study was to reveal the protein composition differences between His bundle (HB) and MC tissues and to determine the distribution of fluorophores in these tissues. This in turn would help to visualize HCS by means of optical-fluorescence biopsy. It has been shown that fluorescence of the soluble fractions of heart tissues is mainly determined by tryptophan (W) and tyrosine (Y) residue emission, while fluorophores, responsible for the fluorescence in the visible region, were found to be hardly extractable from tissues and precipitated out as the insoluble fraction. According to SDS-PAGE, some protein groups specific to MC and HB were revealed. Some SDS-PAGE gel sections containing certain proteins of heart tissue fractions were investigated by spectroscopic methods. The results indicated that proteins of the same weight extracted from different heart tissues exhibit different fluorescence spectra

Individual radiosensitivity as a risk factor for the radiation-induced acute radiodermatitis

Background: Up to 95% of irradiated patients suffer from ionizing radiation (IR) induced early skin reaction, acute radiation dermatitis (ARD). Some experts think that additional skin hydra-tion can reduce acute skin reactions. Individual radiosensitivity (IRS) determined from lymphocytes may help to predict acute radiation toxicity. The purpose of this study is to evaluate the clinical manifestation of ARD in different skincare groups during whole breast radiotherapy depending on IRS and other risk factors. Methods: A total of 108 early-stage breast cancer patients were randomized into best supportive care (BSC) and additional skincare (ASC) groups. IRS was evaluated using a G2 assay modified with caffeine-induced G2 checkpoint arrest. All patients received a 50 Gy dose to the breast planning target volume (PTV). Clinical assessment of ARD symptoms according to the CTCAE grading scale was performed once a week. Results: IRS was successfully determined for 91 out of 108 patients. A total of 10 patients (11%) had normal IRS, 47 patients (52%) were categorized as radiosensitive, and 34 (37%) as highly radiosensitive. There was no significant difference in the manifestation of ARD between patient groups by skincare or IRS. According to logistic regression, patients with bigger breasts were prone to more severe ARD (p = 0.002). Conclusions: The additional skincare did not improve skin condition during RT. A total of 89% of patients had increased radiosensitivity. IRS determined before RT did not show the predictive value for the manifestation of ARD. Logistic regression revealed that breast volume was the most significant risk factor for the manifestation of ARD

Magnetic nanoparticles decorated with gold nanoclusters–applications in cancer theranostics

Nanomedicine presents exciting new opportunities for the detection and treatment of cancer. Current cancer imaging methods and treatment approaches in clinics frequently fall short of entirely curing cancer and can have severe side effects. Theranostic nanoparticles, however, have the potential to revolutionize effective cancer treatment and early cancer detection. The objective of this study is to show how magnetic iron oxide nanoparticles and photoluminescent gold nanoclusters (MN‐AuNCs) may be combined effectively to produce bimodal imaging nanoparticles that possess magnetic and optical properties and can be used for both magnetic resonance imaging and optical biopsy. These findings demonstrate that MN‐AuNCs, when exposed to visible light, also have the capability to produce singlet oxygen, which is necessary for photodynamic therapy of cancer. In addition, it shows that they are non‐toxic, accumulate inside the cells, and cause cell death during exposure to visible light. The creation of these MN‐AuNCs offers a novel remedy for the current shortcomings in cancer diagnosis and treatment. Since they have both therapeutic and imaging capabilities, MN‐AuNCs have the potential to improve patient outcomes while lowering the risk of negative side effects