Fotosenzibilizovana oksidacija lipida u rastvoru indukovana kontinualnim UV-stresom u prisustvu kvercetina

The aim of the present PhD thesis was to study UV(-A and -B) induced lipid peroxidation sensitized by synthetic (benzophenone) and endogenous photosensitizers (bilirubin, riboflavin) in the presence of quercetin as antioxidant. Phospholipid mixure was used as a ”protective target” and the whole process was followed in the simplest possible system – methanolic solution. Photodegradation of sensitizers and quercetin with the consequent occurrence of their degradation products both individually and in the mutual mixture, as well as in the mixture with phospholipids (where beside the mentioned processes peroxides production occurs), was followed by RP-HPLC chromatography. Unambiguous identification of degradation products was enabled by UHPLC-ESI-MS technique while free radical species were identified by EPR spectroscopy. Benzophenone was photostabile, photodegradation of bilirubin gave biliverdin and dipiroles while main degradation products of riboflavin were lumichrome and lumiflavin. Insight into the mechanism and control of lipid peroxidation provided ”conjugated diene” assay, by following the signal at 234 nm (the absorption maximum of conjugated diene structures). As typical Type I sensitizer, benzophenone generated superoxide radical anion, while riboflavin generated both superoxide and singlet oxygen by mixed Type I and II mechanisms. Irradiation of bilirubin-riboflavin mixture showed, in the indirect way, that bilirubin is typical Type II sensitizer. Photosensitizing capability of the studied sensitizers decreases in the order: riboflavin > benzophenone > bilirubin. Quercetin exhibited efficient antioxidant activity, mediated by its own degradation, in terms of its preventive (absorbing UV radition), chain-breaking activities (scavenging of generated superoxide radical anion, singlet oxygen and lipid peroxides) and besides all this effectively quenched triplet exited states of sensitizers (first of all benzophenone and riboflavin)

Nematicidal Activity of Essential Oils on a Psychrophilic Panagrolaimus sp. (Nematoda: Panagrolaimidae)

Essential oils (EOs) have historically been used for centuries in folk medicine, and nowadays they seem to be a promising control strategy against wide spectra of pathogens, diseases, and parasites. Studies on free-living nematodes are scarce. The free-living microbivorous nematode Panagrolaimus sp. was chosen as the test organism. The nematode possesses extraordinary biological properties, such as resistance to extremely low temperatures and long-term survival under minimal metabolic activity. Fifty EOs from 22 plant families of gymnosperms and angiosperms were tested on Panagrolaimus sp. The aims of this study were to investigate the in vitro impact of EOs on the psychrophilic nematode Panagrolaimus sp. in a direct contact bioassay, to list the activity of EOs based on median lethal concentration (LC50), to determine the composition of the EOs with the best nematicidal activity, and to compare the activity of EOs on Panagrolaimus sp. versus plant parasitic nematodes. The results based on the LC50 values, calculated using Probit analysis, categorized the EOs into three categories: low, moderate and highly active. The members of the laurel family, i.e., Cinnamomum cassia and C. burmannii, exhibited the best nematicidal activity. Aldehydes were generally the major chemical components of the most active EOs and were the chemicals potentially responsible for the nematicidal activity

Cardiovascular risk factors in 7-13 years old children from Vojvodina (Serbia)

Background: Atherosclerosis is a chronic inflammatory disease which starts early in life and depends on many factors, an important one being dyslipoproteinemia. According to several studies, atherosclerotic plaques or their precursors could be seen in children younger than 10 years. During later life, interaction with a sedentary way of life, as well as unhealthy nutrition, smoking, alcohol consumption, obesity and family history of cardiovascular disease cause the burden of atherosclerotic disease. Methods: Study included 624 children (316 boys, 308 girls), aged from 7-13 years. We analysed socio-demographic data (BMI, blood pressure, cardiovascular family history, smoking status), as well as lipid status with lipoprotein little a-Lp(a), and apolipoproteins: Apo AI, Apo B-100 for all children. This enabled us to calculate new atherogenic indices Tg/HDL-c, lipid tetrad index (LTI) and lipid pentad index (LPI). Cardiovascular risk for later life was estimated by using modified Risk Score for Young Individuals (RS), which divided the subjects according to the score level: low, medium and higher risk. Results: The older children (13 y) had better lipid status than the younger children, i.e. significantly lower total cholesterol, LDL-C, triglycerides and non-HDL-C concentration and significantly higher HDL-C concentration than the younger children and this was in accordance with the RS level. Children with a positive family history of CV disease had significantly higher Lp(a) concentration and blood pressure. LPI was significantly higher in children with a higher RS. Conclusions: The results of our work could be used for cardiovascular risk assessment in apparently healthy children to provide preventive measures which could control the change able risk factors

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Fotosenzibilizovana oksidacija lipida u rastvoru indukovana kontinualnim UV-stresom u prisustvu kvercetina

The aim of the present PhD thesis was to study UV(-A and -B) induced lipid peroxidation sensitized by synthetic (benzophenone) and endogenous photosensitizers (bilirubin, riboflavin) in the presence of quercetin as antioxidant. Phospholipid mixure was used as a ”protective target” and the whole process was followed in the simplest possible system – methanolic solution. Photodegradation of sensitizers and quercetin with the consequent occurrence of their degradation products both individually and in the mutual mixture, as well as in the mixture with phospholipids (where beside the mentioned processes peroxides production occurs), was followed by RP-HPLC chromatography. Unambiguous identification of degradation products was enabled by UHPLC-ESI-MS technique while free radical species were identified by EPR spectroscopy. Benzophenone was photostabile, photodegradation of bilirubin gave biliverdin and dipiroles while main degradation products of riboflavin were lumichrome and lumiflavin. Insight into the mechanism and control of lipid peroxidation provided ”conjugated diene” assay, by following the signal at 234 nm (the absorption maximum of conjugated diene structures). As typical Type I sensitizer, benzophenone generated superoxide radical anion, while riboflavin generated both superoxide and singlet oxygen by mixed Type I and II mechanisms. Irradiation of bilirubin-riboflavin mixture showed, in the indirect way, that bilirubin is typical Type II sensitizer. Photosensitizing capability of the studied sensitizers decreases in the order: riboflavin > benzophenone > bilirubin. Quercetin exhibited efficient antioxidant activity, mediated by its own degradation, in terms of its preventive (absorbing UV radition), chain-breaking activities (scavenging of generated superoxide radical anion, singlet oxygen and lipid peroxides) and besides all this effectively quenched triplet exited states of sensitizers (first of all benzophenone and riboflavin)

Benzophenone Suppression of Quercetin Antioxidant Activity towards Lipids under UV-B Irradiation Regime: Detection by HPLC Chromatography

Quercetin, a well-known flavonoid antioxidant, has been employed to control benzophenone-sensitized peroxidation of the lipid mixture in methanol solution, induced by continuous UV-B irradiation. Surprisingly, the detected quercetin antioxidant activity was almost negligible. The presented data suggests that the reason is not in its own UV-B-induced degradation but rather in its interrelationship with benzophenone during UV-B stress. On the other side of this relationship, benzophenone anticipated sensitizing role towards lipids; that is, the initiation of lipid peroxidation has been affected as well. These results, obtained by HPLC chromatography, partly confirm but partly relativize to some extent recent results obtained with the same system by spectrophotometric method

Irreversible UV-induced quercetin and rutin degradation in solution, studied by UV-spectrophotometry and HPLC chromatography

Irreversible degradation of quercetin and rutin, dissolved in methanol and water, induced by continuous UV-irradiation from two different sub-ranges (UV-B and UV-C) has been studied in this work. The degradation of both flavonoids is related to formation of UV-induced degradation products: both processes follow first-order kinetics. The degradation and products formation rate constants are both dependent on the involved UV-photons energy input in both solvents

UV-induced change in quercetin antioxidant activity toward benzophenone initiated lipid peroxidation

The aim of this work is to estimate the degradation and change in antioxidant activity of quercetin in the presence of two different mixtures of phospholipids in methanol solution, under continuous UV-irradiation from three different sub-ranges (UV-A, UV-B and UV-C), in the presence and in the absence of selected UV-absorbing photosensitizer, benzophenone. Quercetin is employed to control lipid peroxidation process generated by UV-irradiation, by absorbing part of the UV-incident light, or/and by scavenging the involved, created free radicals. The results show that quercetin undergoes to irreversible destruction, highly dependent on UV-photons energy input, more expressed in the presence than in the absence of benzophenone. In the same time quercetin expresses suppression effect on lipid peroxidation processes in UV-irradiated phospholipid mixtures in both cases - absence or presence of benzophenone (more or less effective, respectively). In UV-C-irradiated mixtures, benzophenone photosensitizing function is significantly reduced due to its strong absorption in the same UV-C spectral range, therefore affecting less antioxidant activity of the remained quercetin