Autofluorescence Spectroscopy and Imaging II: A Special Issue Aimed to Promote Optically Based Studies on Biological Substrates

The Journal Molecules, in particular the Photochemistry Section, and the younger Journal Photochem are active in promoting the advances and practical applications based on the interaction of light with the various biological substrates from both animal and vegetal systems [...]

Lutein and Zeaxanthin Distribution in the Healthy Macula and Its Association with Various Demographic Factors Examined in Pseudophakic Eyes

The macular pigment consisting of lutein (L) and zeaxanthin (Z) protects photoreceptors via its antioxidative and barrier activities. This study aimed to determine L and Z distribution in the healthy macula and their association with various demographic factors. Macular pigment optical density (MPOD) was measured using fundus autofluorescence spectroscopy in 352 pseudophakic eyes with no fundus diseases. Pseudophakia was chosen to avoid the influence of cataract in the measurement of fundus autofluorescence. The mean patient age was 72.3 ± 8.6 years. MPOD was analyzed separately in three zones, i.e., A: a central area within a radius of 0.5°, mainly containing Z; B: a ring area with radii from 0.5° to 1.3°, containing Z and L; C: a ring area with radii from 1.3° to 9°, containing L. Multivariate analyses were performed with MPOD as the dependent variable and sex, supplement intake, smoking habits, glaucoma, diabetes, age, body mass index (BMI), skin carotenoid levels, retinal thickness, retinal volume, axial length as the independent variables. The mean total MPOD volume within 9° eccentricity was 20,121 ± 6293. Age was positively associated with MPOD in all zones. Supplement and BMI were positively and negatively associated with MPOD in zones B and C. Smoking was negatively associated with MPOD in zone A. This study revealed the standard MP values of aged Japanese, which resulted to be higher than the previously reported values in other races. Age was found to have a positive association with MP values. L in the outer foveola was affected by BMI and supplements, but Z in the foveola was not. The amount of Z in the Müller cell cone may not be changed easily by factors such as hunger and satiety in the context of preservation of homeostasis in the human body, but tobacco had a negative effect on Z.

Cellular NADH and NADPH Conformation as a Real-Time Fluorescence-Based Metabolic Indicator under Pressurized Conditions

Cellular conformation of reduced pyridine nucleotides NADH and NADPH sensed using autofluorescence spectroscopy is presented as a real-time metabolic indicator under pressurized conditions. The approach provides information on the role of pressure in energy metabolism and antioxidant defense with applications in agriculture and food technologies. Here, we use spectral phasor analysis on UV-excited autofluorescence from Saccharomyces cerevisiae (baker’s yeast) to assess the involvement of one or multiple NADH- or NADPH-linked pathways based on the presence of two-component spectral behavior during a metabolic response. To demonstrate metabolic monitoring under pressure, we first present the autofluorescence response to cyanide (a respiratory inhibitor) at 32 MPa. Although ambient and high-pressure responses remain similar, pressure itself also induces a response that is consistent with a change in cellular redox state and ROS production. Next, as an example of an autofluorescence response altered by pressurization, we investigate the response to ethanol at ambient, 12 MPa, and 30 MPa pressure. Ethanol (another respiratory inhibitor) and cyanide induce similar responses at ambient pressure. The onset of non-two-component spectral behavior upon pressurization suggests a change in the mechanism of ethanol action. Overall, results point to new avenues of investigation in piezophysiology by providing a way of visualizing metabolism and mitochondrial function under pressurized conditions.

Characteristics of examination algorithm of patients with chronic trauma of the oral mucosa using tissue autofluorescence spectroscopy

Relevance. The paper demonstrates the need to implement modern diagnostic techniques for diagnosis of precancerous and cancerous lesions at early or preclinical stages. Additional diagnostic methods are necessary, e.g. tissue autofluorescence, which allows revealing insidious pathological risk zones, particularly precancerous and cancerous lesions, to evaluate the condition of the oral tissues in patients with chronic oral mucosa disorders, especially caused by trauma. Purpose – to assess trauma-specific effectiveness of autofluorescence spectroscopy (AFS) in risk group patients with chronic trauma of the oral mucosa to reveal early malignization signs.Materials and methods. 25 subjects were selected for the study and divided into 2 groups: main group – 20 patients with different manifestations of chronic oral mucosa trauma; control group – 5 subjects without visible clinical manifestations and without oral trauma factors. Autofluorescence spectroscopy was performed in both groups using AFS-400 stomatoscope.Results. The received data demonstrated that the change in autofluorescence doesn’t allow drawing final conclusions on the presence or absence of chronic oral trauma malignization signs.Conclusion. AFS-400 stomatoscope may be effective in differentiating between healthy and damaged tissues, but there is no solid evidence that the change in fluorescence shade can help differentiate between various types of damaged tissues. Autofluorescence spectroscopy should be considered as an additional method for examination of patients with chronic oral mucosa trauma to reveal early malignization signs.

CLINICALEVALUATION OF ORAL CAVITYSTATUS IN PATIENTS WITH KERATINIZATION D

Pathological processes associated with disturbed keratinization and risks of cancer tend to become more common and affect younger people. However, the currently available diagnostic methods are not always reliable, which explains the need to further study this. The aim of the study was to improve the efficiency of early diagnosis of keratoses of the oral cavity under autofluorescence spectroscopy incorporated into the proposed screening algorithm. The examination methods involved clinical, luminescent, analytical, statistical evaluation. The study allowed obtaining optical images through autofluorescence stomatoscopy in patients with keratinization disorders, identifying their color range within affected and healthy tissues, as well as confirming their reliability employing the Color Spatioplotter ver 2.46 software. The tested autofluorescent stomatoscopy method featured sufficient sensitivity (98%) against relative specificity (75%), with prediction of a positive outcome (100%).