The terms 'antioxidant', 'oxidative stress' and 'oxidative damage' are widely used but rarely defined. This brief review attempts to define them and to examine the ways in which oxidative stress and oxidative damage can affect cell behaviour both in vivo and in cell culture, using cancer as an example.

Biochemistry of oxidative stress

Honeybees products comprise of numerous substances, including propolis, bee pollen, and royal jelly, which have long been known for their medicinal and health-promoting properties. Their wide biological effects have been known and used since antiquity. Bee products are considered to be a potential source of natural antioxidants such as flavonoids, phenolic acids, or terpenoids. Nowadays, the still growing concern in natural substances capable of counteracting the effects of oxidative stress underlying the pathogenesis of numerous diseases, such as neurodegenerative disorders, cancer, diabetes, and atherosclerosis, as well as negative effects of different harmful factors and drugs, is being observed. Having regarded the importance of acquiring drugs from natural sources, this review is aimed at updating the current state of knowledge of antioxidant capacity of selected bee products, namely, propolis, bee pollen, and royal jelly, and of their potential antioxidant-related therapeutic applications. Moreover, the particular attention has been attributed to the understanding of the mechanisms underlying antioxidant properties of bee products. The influence of bee species, plant origin, geographic location, and seasonality as well as type of extraction solutions on the composition of bee products extracts were also discussed.

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Antioxidant Potential of Propolis, Bee Pollen, and Royal Jelly: Possible Medical Application

Opinions on the interdependence between diabetes mellitus and oral periodontal disease are controversial. Experimental and clinical investigations carried out so far have not brought unique results. General objective of our research is to investigate on the strictly defined group of subjects aged 35-44 with diabetes mellitus type I the influence of metabolic control HbA1C on changes of periodontium and other organs. According to duration of diabetes mellitus the patients are divided into subdecade and postdecade groups. This group consists of 56 patients out of which 33 patients are with subdecade and 23 with postdecade insulin-dependent diabetes mellitus. In this group periodontal pocket depths, gingival index, number of extracted teeth and the volume of nonstimulated saliva are measured in comparison with a control group. The incidence of oral diseases and complications in other organs of insulin-dependent patients in subdecade and postdecade period are also examined and recorded. Periodontal diabetic disease is verified by pathohistological findings. Values of HbA1C in either subdecade or postdecade group with diabetes mellitus are above normal values. Values of periodontal pocket depths as well as the values of gingival index are substantially greater at insulin-dependent diabetes mellitus patients compared to the control group.

Diabetes mellitus and periodontal diseases

Metformin was proposed to be a candidate for host-directed therapy for COVID-19. However, its efficacy remains to be validated. In this study, we compared the outcome of metformin users and nonusers in hospitalized COVID-19 patients with diabetes. Hospitalized diabetic patients with confirmed COVID-19 in the Tongji Hospital of Wuhan, China, from January 27, 2020 to March 24, 2020, were grouped into metformin and no-metformin groups according to the diabetic medications used. The demographics, characteristics, laboratory parameters, treatments, and clinical outcome in these patients were retrospectively assessed. A total of 283 patients (104 in the metformin and 179 in the no-metformin group) were included in this study. There were no significant differences between the two groups in gender, age, underlying diseases, clinical severity, and oxygen-support category at admission. The fasting blood glucose level of the metformin group was higher than that of the no-metformin group at admission and was under effective control in both groups after admission. Other laboratory parameters at admission and treatments after admission were not different between the two groups. The length of hospital stay did not differ between the two groups (21.0 days for metformin versus 19.5 days for no metformin, P = 0.74). However, in-hospital mortality was significantly lower in the metformin group (3/104 (2.9%) versus 22/179 (12.3%), P = 0.01). Antidiabetic treatment with metformin was associated with decreased mortality compared with diabetics not receiving metformin. This retrospective analysis suggests that metformin may offer benefits in patients with COVID-19 and that further study is indicated.

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Metformin Treatment Was Associated with Decreased Mortality in COVID-19 Patients with Diabetes in a Retrospective Analysis.

Oxidative stress in neurodegeneration: cause or consequence?

Abstract BACKGROUND: Chronically elevated alpha-2-macroglobulin (A2MG) in the blood has been correlated with diabetes and the HbA1c profile; however, no systematic review has been conducted to evaluate the association of A2MG salivary levels and glycemia or HbA1c levels in diabetes mellitus type 2 (DM2) patients. OBJECTIVE: To evaluate whether A2MG salivary levels are related to the glycemia or HbA1c levels in DM2 patients. DESIGN AND SETTING: Systematic review developed at Universidade Federal de Uberlândia (UFU), Brazil. METHODS: Eight databases were used as research sources. The eligibility criteria included studies that reported data regarding mean salivary A2MG and the correlation between glycemia and/or HbA1c levels of DM2 subjects (uncontrolled and well-controlled) and non-diabetic subjects. The risk of bias of the studies selected was assessed using the Joanna Briggs Institute (JBI) critical appraisal tools for use in JBI systematic reviews. Pooled correlation coefficients were estimated using the Hunter-Schmidt method. Study estimates were weighted according to their sample size, and heterogeneity was calculated using the chi-square statistic. RESULTS: Four studies on DM2 patients were included in this systematic review after careful analysis of 1482 studies. Three studies compared A2MG with HbA1c and glycemia. Overall, the correlation between A2MG and HbA1c was strong (r = 0.838). In contrast, the correlation between A2MG and glycemia was low (r = 0.354). CONCLUSION: The strong association between HbA1C and salivary A2MG suggests that this salivary protein has the potential to be a surrogate for HbA1C, if corroboratory further evidence is obtained through large-scale studies.

Association of salivary alpha-2-macroglobulin with glycemia and glycated hemoglobin in type 2 diabetes mellitus: a systematic review and meta-analysis study

https://doi.org/10.1016/j.jdsr.2023.06.004

Salivary SARS-CoV-2 RNA for diagnosis of COVID-19 patients: a systematic revisew and meta-analysis of diagnostic accuracy

Zika virus (ZIKV) diagnosis is currently performed through an invasive, painful, and costly procedure using molecular biology. Consequently, the search for a non-invasive, more cost-effective, reagent-free, and sustainable method for ZIKV diagnosis is of great relevance. It is critical to prepare a global strategy for the next ZIKV outbreak given its devastating consequences, particularly in pregnant women. Attenuated total reflection–Fourier transform infrared (ATR-FTIR) spectroscopy has been used to discriminate systemic diseases using saliva; however, the salivary diagnostic application in viral diseases is unknown. To test this hypothesis, we intradermally challenged interferon-gamma gene knockout C57/BL6 mice with ZIKV (50 µL,105 FFU, n = 7) or vehicle (50 µL, n = 8). Saliva samples were collected on day three (due to the peak of viremia) and the spleen was also harvested. Changes in the salivary spectral profile were analyzed by Student’s t test (p < 0.05), multivariate analysis, and the diagnostic capacity by ROC curve. ZIKV infection was confirmed by real-time PCR of the spleen sample. The infrared spectroscopy coupled with univariate analysis suggested the vibrational mode at 1547 cm−1 as a potential candidate to discriminate ZIKV and control salivary samples. Three PCs explained 93.2% of the cumulative variance in PCA analysis and the spectrochemical analysis with LDA achieved an accuracy of 93.3%, with a specificity of 87.5% and sensitivity of 100%. The LDA-SVM analysis showed 100% discrimination between both classes. Our results suggest that ATR-FTIR applied to saliva might have high accuracy in ZIKV diagnosis with potential as a non-invasive and cost-effective diagnostic tool.

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Salivary Detection of Zika Virus Infection Using ATR-FTIR Spectroscopy Coupled with Machine Learning Algorithms and Univariate Analysis: A Proof-of-Concept Animal Study

Douglas Carvalho Caixeta

Papers

Association of salivary alpha-2-macroglobulin with glycemia and glycated hemoglobin in type 2 diabetes mellitus: a systematic review and meta-analysis study

Salivary SARS-CoV-2 RNA for diagnosis of COVID-19 patients: a systematic revisew and meta-analysis of diagnostic accuracy

Salivary Detection of Zika Virus Infection Using ATR-FTIR Spectroscopy Coupled with Machine Learning Algorithms and Univariate Analysis: A Proof-of-Concept Animal Study