Artificial intelligence approaches to the biochemistry of oxidative stress: Current state of the art

Artificial intelligence (AI) and machine learning models are today frequently used for classification and prediction of various biochemical processes and phenomena. In recent years, numerous research efforts have been focused on developing such models for assessment, categorization, and prediction of oxidative stress. Supervised machine learning can successfully automate the process of evaluation and quantification of oxidative damage in biological samples, as well as extract useful data from the abundance of experimental results. In this concise review, we cover the possible applications of neural networks, decision trees and regression analysis as three common strategies in machine learning. We also review recent works on the various weaknesses and limitations of artificial intelligence in biochemistry and related scientific areas. Finally, we discuss future innovative approaches on the ways how AI can contribute to the automation of oxidative stress measurement and diagnosis of diseases associated with oxidative damage.

Iron-based nanoparticles and their potential toxicity: Focus on oxidative stress and apoptosis

Recently, there have been several studies indicating that iron-based nanomaterials may exhibit certain toxic properties. Compared to conventional iron and iron oxides, iron nanoparticles (FeNPs) have some unique physical and chemical traits which impact their absorption, biodistribution and elimination. Facilitated passage through biological barriers enables FeNPs to reach various tissues and cells, and interact with a variety of different compounds. Currently, most of the recent research is focused on the potential cytotoxicity of FeNPs, and its implications on cell viability and functions. Some studies suggested that, in certain cell types, FeNPs may increase levels of oxidative stress and induce generation of reactive oxygen species. Oxidative stress may be one of the most important mechanisms by which FeNPs exhibit cytotoxic effects. Some authors have also suggested that, in certain conditions, exposure to FeNPs, in combination with other factors, may lead to changes in intracellular signaling resulting in programmed cell death. In this short review, we focus on the recent research on potential cytotoxicity of iron-based nanomaterials, and the potential implications of this new knowledge in medicine, chemistry and biology.

Application of Iron Oxide Nanoparticles in Contemporary Experimental Physiology and Cell Biology Research

Recent findings have suggested that iron oxide nanoparticles (IONPs) have some exceptional chemical characteristics which make them useful in both experimental physiology and cell biology research. These nanoparticles might be applied as drug delivery systems for anti-cancer and other medications. Also, IONPs might be a valuable part of many novel bioassays in various fundamental medical fields. In recent years, several studies have indicated that IONPs may have certain cytotoxic and genotoxic potential in living systems. During in vitro conditions, IONPs might induce generation of reactive oxygen species and cause oxidative stress in some cell populations. The toxicity of IONPs is not yet fully understood, and additional research is needed to confirm if IONPs have detrimental effects on human health. This short article focuses on the recent developments and trends in the fields of nanomedicine and nanobiology regarding iron oxide nanomaterials and their application in fundamental medical disciplines such as experimental physiology. We discuss our previously published works on structural effects of IONPs and other metallic nanoparticles on cell nucleus in in vitro conditions. We also describe our recent findings regarding the impact of IONPs on certain biophysical properties of subcellular components.

Age-related reduction of chromatin fractal dimension in toluidine blue - stained hepatocytes

In this study, we proposed a hypothesis that chromatin of mouse hepatocytes exhibits age-related reduction of fractal dimension. This hypothesis was based on previously published works demonstrating that complexity of biological systems such as tissues, decreases during the process of physiological aging. Liver tissue was obtained from 24 male mice divided into 3 age groups: 10-days-old (young, juvenile), 210-days-old (adult) and 390-days-old. The tissue was stained using a modification of toluidine blue (nucleic acid - specific) staining method. A total of 480 chromatin structures (20 for each animal) were analyzed. For each structure, the values of fractal dimension, lacunarity, textural angular second moment and inverse difference moment were calculated using ImageJ software and its plugins. The results indicated the age-related reduction in fractal dimension and increase in lacunarity (p<0.01). Fractal dimension is a potentially good indicator of age associated changes in chromatin structure. To our knowledge, this is the first study to show that fractal complexity of hepatocyte chromatin decreases during the process of physiological aging. Fractal analysis as a method could be useful in detection of small age-related changes in chromatin distribution not otherwise visible with naked eye on conventional tissue micrographs.

Cardiac autonomic dysfunction in patients with gastroesophageal reflux disease

AIM: To investigate autonomic nervous function in patients with a diagnosis of gastroesophageal reflux disease (GERD).

METHODS: The investigation was performed on 29 patients (14 men), aged 18-80 years (51.14 ± 18.34), who were referred to our Neurocardiology Laboratory at the Clinical and Hospital Center “Bezanijska Kosa” with a diagnosis of GERD. One hundred sixteen healthy volunteers matched in age and sex with the examinees served as the control group. The study protocol included the evaluation of autonomic function and hemodynamic status, short-term heart rate variability (HRV) analysis, 24 h ambulatory ECG monitoring with long-term HRV analysis and 24 h ambulatory blood pressure monitoring.

RESULTS: Pathologic results of cardiovascular reflex test were more common among patients with reflux compared to the control group. Severe autonomic dysfunction was detected in 44.4% of patients and in 7.9% of controls (P < 0.001). Parameters of short-term analysis of RR variability, which are the indicators of vagal activity, had lower values in patients with GERD than in the control group. Long-term HRV analysis of time-domain parameters indicated lower values in patients with reflux disease when compared to the control group. Power spectral analysis of long-term HRV revealed lower low- and high-frequency values. Detailed 24 h ambulatory blood pressure analysis showed significantly higher values of systolic blood pressure and pulse pressure in the reflux group than in the control group.

CONCLUSION: Patients with GERD have distortion of sympathetic and parasympathetic components of the autonomic nervous system, but impaired parasympathetic function appears more congruent to GERD.

Nuclear entropy, angular second moment, variance and texture correlation of thymus cortical and medullar lymphocytes: grey level co-occurrence matrix analysis

Grey level co-occurrence matrix analysis (GLCM) is a well-known mathematical method for quantification of cell and tissue textural properties, such as homogeneity, complexity and level of disorder. Recently, it was demonstrated that this method is capable of evaluating fine structural changes in nuclear structure that otherwise are undetectable during standard microscopy analysis. In this article, we present the results indicating that entropy, angular second moment, variance, and texture correlation of lymphocyte nuclear structure determined by GLCM method are different in thymus cortex when compared to medulla. A total of 300 thymus lymphocyte nuclei from 10 one-month-old mice were analyzed: 150 nuclei from cortex and 150 nuclei from medullar regions of thymus. Nuclear GLCM analysis was carried out using National Institutes of Health ImageJ software. For each nucleus, entropy, angular second moment, variance and texture correlation were determined. Cortical lymphocytes had significantly higher chromatin angular second moment (p < 0.001) and texture correlation (p < 0.05) compared to medullar lymphocytes. Nuclear GLCM entropy and variance of cortical lymphocytes were on the other hand significantly lower than in medullar lymphocytes (p < 0.001). These results suggest that GLCM as a method might have a certain potential in detecting discrete changes in nuclear structure associated with lymphocyte migration and maturation in thymus.

Age-related reduction of structural complexity in spleen hematopoietic tissue architecture in mice

The effects of aging on structural complexity in hematopoietic tissue are unknown. In this work, in a mouse experimental model, we report the age-related reduction of spleen hematopoietic tissue (SHT) complexity. Spleen tissue was obtained from the total of 64 male Swiss albino mice divided into 8 age groups: newborns (0 days old), 10 days, 20 days, 30 days, 120 days, 210 days, 300 and 390 days old. SHT was stained using conventional hematoxylin/eosin, and DNA-binding toluidine blue dyes. Fractal dimension as an indicator of cellular complexity, and lacunarity as indicator of tissue heterogeneity were determined based on the binarized SHT micrographs. Results indicate that fractal dimension of mice spleen hematopoietic tissue decreases with age, while lacunarity increases. These changes/trends have been detected in SHT stained both with toluidine blue and conventional hematoxylin/eosin. Fractal dimension was negatively correlated with lacunarity. The detected reduction in complexity suggests that age-related structural changes are present in mouse SHT both in general tissue architecture and progenitor cell DNA.

Aging increases nuclear chromatin entropy of erythroid precursor cells in mice spleen hematopoietic tissue

Despite recent advances in hematopoietic tissue research, effects of aging on hematopoietic erythroid precursor (EP) cells are unclear. In this article we present results suggesting that chromatin textural entropy of EP cells in mouse spleen increases with age, while chromatin homogeneity decreases. The experiment was conducted on a total of 32 male Swiss white mice. Spleen tissue was acquired from four age groups: 10 days, 1 month, 4 months, and 7 months old mice. A total of 640 randomly selected, nonoverlapping EP cell nuclei (20 per animal) were analyzed using the gray level co-occurrence matrix method. There was statistically highly significant difference between the age groups, both in chromatin entropy (ANOVA, F = 12.99, p < 0.0001) and in homogeneity (ANOVA, F = 7.05, p < 0.001). When the individual groups were compared (ANOVA post hoc test), statistical difference was detected in all group pairs, except between the animals 4 months and 7 months old, either in chromatin entropy or homogeneity. The detected increase of chromatin disorder in mouse juvenile period/early adulthood suggests that cell intrinsic factors such as epigenetic dysregulation and DNA damage accumulation may have an important role in EP cell aging.

Screen viewing, body mass index, cigarette smoking and sleep duration in Belgrade University student population: results of an observational, cross-sectional study

BACKGROUND

Subjects that spend more time working on computers or watching television could have a higher body mass index.

AIM

To assess the relationship between time spent in front of a screen and studying, body mass index (BMI), smoking, and sleep duration among university students.

MATERIAL AND METHODS

A cross-sectional study of 734 randomly selected students aged 21 ± 2 years (450 females) that responded an anonymous, structured questionnaire about time spent watching television or in front of a computer, time spent studying, number of daily hours of sleep, smoking habits and number of daily meals. Body mass index was also calculated for all subjects

RESULTS

Among males, the number of daily sleep hours, time spent working with computers and number of daily meals were significantly higher and time spent studying was significantly lower than females. Nonsmokers ate a significantly higher number of meals and spent less time watching television. No association was observed between time spent in front of a screen and number of sleep hours of body mass index.

CONCLUSIONS

Men and smokers spend more time working in computers. There is no association between body mass index and time spent in front of screens.