Susceptibility to oxidative stress, insulin resistance, and insulin secretory response in the development of diabetes from obesity

Background/Aim. Oxidative stress plays a critical role in the pathogenesis of various diseases. Recent reports indicate that obesity may induce systemic oxidative stress. The aim of the study was to potentiate oxidative stress as a factor which may aggravate peripheral insulin sensitivity and insulinsecretory response in obesity in this way to potentiate development of diabetes. The aim of the study was also to establish whether insulin-secretory response after glucagonstimulated insulin secretion is susceptible to prooxidant/ antioxidant homeostasis status, as well as to determine the extent of these changes. Methods. A mathematical model of glucose/insulin interactions and C-peptide was used to indicate the degree of insulin resistance and to assess their possible relationship with altered antioxidant/prooxidant homeostasis. The study included 24 obese healthy and 16 obese newly diagnozed non-insulin dependent diabetic patients (NIDDM) as well as 20 control healthy subjects, matched in age. Results. Total plasma antioxidative capacity, erythrocyte and plasma reduced glutathione level were significantly decreased in obese diabetic patients, but also in obese healthy subjects, compared to the values in controls. The plasma lipid peroxidation products and protein carbonyl groups were significantly higher in obese diabetics, more than in obese healthy subjects, compared to the control healthy subjects. The increase of erythrocyte lipid peroxidation at basal state was shown to be more pronounced in obese daibetics, but the apparent difference was obtained in both the obese healthy subjects and obese diabetics, compared to the control values, after exposing of erythrocytes to oxidative stress induced by H2O2. Positive correlation was found between the malondialdehyde (MDA) level and index of insulin sensitivity (FIRI). Conclusion. Increased oxidative stress together with the decreased antioxidative defence seems to contribute to decreased insulin sensitivity and impaired insulin secretory response in obese diabetics, and may be hypothesized to favour the development of diabetes during obesity

Fractal analysis and microstructure development PVDF based multifunctional material

Polyvinylidene fluoride (PVDF) is a novel gel polymer electrolyte alternative which can reduce the risk of irreversible failure in lithium-ion batteries (LIB) [1]. PVDF matrix structures which exhibit inter-crosslinking networks have previously demonstrated favorable thermal and mechanical properties for LIB applications [2]. PVDF based multifunctional material is attracting a great scientific interest due to its excellent piezoelectric, pyroelectric and ferroelectric properties. Such as, its properties strongly depend on synthesis procedures and obtained microstructures. In this research, porous structure and cross-linking patterns of PVDF were prepared by electrospinning method and it has been found that these microstructures can have fractal structure. Fractal analysis can be used as a powerful tool for describing structural and functional properties of these this material. Because of that, in this research we have used different fractal methods for the reconstructions of various PVDF microstructure morphologies. Fractal analysis has been performed by using scanning electron microscope micrographs and computational modeling tools. Theory of Iterated Function Systems and Voronoi tessellation, have been used for modeling PVDF porous structures. A Python algorithm was created to determine the distribution of pore areas in SEM micrographs. Algorithm’s distribution of calculated pore surface areas were compared with measured pore surface areas and fractal reconstructions of different morphologies and their connection with functional properties were analyzed

Salt-induced changes in the antioxidant system and viability of oilseed rape

This work was aimed to investigate the effect of salt (NaCl) stress on three oilseed rape (Brassica napus L.) cultivars: 'Banacanka', 'Jasna' and 'Kata'. The following parameters were determined: antioxidant enzymes superoxide dismutase (SOD) and guaiacol peroxidase (GPX), reduced glutathione (GSH) quantity, lipid peroxidation (LP) intensity, radical-scavenging capacity (DPPH-RSC), hydroxyl radical scavenging ((OH)-O-center dot radicals) and ferric reducing antioxidant power (FRAP). Seed viability was determined using the standard laboratory test for germination as well as the seed accelerated aging test measuring the germination, shoot and root length. The plants were subjected to three salt treatments: 0, 100, 150 and 200 mmol dm(-3) NaCl for 7 days. All three cultivars responded with an increase of lipid peroxidation in seedlings and with a decrease of GPX activity. 'Banacanka' was found to be the most vulnerable cultivar, with an increase of 237% of LP intensity in comparison to the control at the highest NaCl concentration. The induction of the SOD activity was observed for all three cultivars by different NaCl concentrations. The antioxidant capacity measured by FRAP, DPPH-RSC and (OH)-O-center dot radicals was also induced, especially FRAP at the highest concentration in the cultivar 'Jasna' (by 282%). Germination, shoot and root length decreased for all investigated cultivars. Our results showed that cultivar 'Jasna' is the most adapted to salt stress because of the highest SOD activity and accumulation of antioxidants. Furthermore, this research suggests that some of the antioxidant parameters can be useful biochemical markers for the selection of oilseed rape tolerant cultivars under the conditions of salinity

Fractal analysis and microstructure development of BaTiO3 and PVDF based multifunctional materials

Barium titanate (BaTiO3) and polyvinylidene fluoride (PVDF) based multifunctional materials are attracting a great scientific interest due to their excellent piezoelectric, pyroelectric and ferroelectric properties. These materials undergo controlled transformations through physical interactions and respond to environmental stimuli, such as temperature, pressure, electric and magnetic fields. Their properties strongly depend on synthesis procedures and obtained microstructures. This include intergranular contact surfaces of BaTiO3 based materials, as well as, porous structure and cross-linking patterns of PVDF prepared by electrospinning. It has been found that these microstructures can have fractal structure and that the fractal analysis can be used as a powerful tool for describing structural and functional properties of these materials. Having this in mind, in this research we have used different fractal methods for the reconstructions of various BaTiO3 and PVDF microstructure morphologies. Fractal analysis has been performed by using scanning electron microscope micrographs and computational modeling tools. Fractal dimension of irregular morphologies which exhibit fractal regularity were determined by using box-counting method. This method enables the analysis of self-similar microstructure morphologies by quantifying the rate at which an object's geometrical details develop at increasingly fine scales. Theory of Iterated Function Systems and Voronoi tessellation, have been used for modeling BaTiO3 random microstructures and PVDF porous structures. A python algorithm was created to determine the distribution of pore areas in SEM micrographs. Algorithm’s distribution of calculated pore surface areas was compared with measured pore surface areas and fractal reconstructions of different morphologies and their connection with functional properties were analyzed

Impact of intensive insulin treatment on the development and consequences of oxidative stress in insulin-dependent diabetes mellitus

Background/Aim. The aim of this study, which included patients with insulin-dependent diabetes mellitus, was to determine the influence of the application of various treatment modalities (intensive or conventional) on the total plasma antioxidative capacity and lipid peroxidation intensity expressed as malondialdehyde (MDA) level, catalase and xanthine oxidase activity, erythrocyte glutatione reduced concentration (GSH RBC), erythrocyte MDA level (MDA RBC), as well as susceptibility of erythrocyte to H2O2-induced oxidative stress. Methods. This study included 42 patients with insulin-dependent diabetes mellitus. In 24 of the patients intensive insulin treatment was applied using the model of short-acting insulin in each meal and medium- acting insulin before going to bed, while in 18 of the patients conventional insulin treatment was applied in two (morning and evening) doses. In the examined patients no presence of diabetes mellitus complications was recorded. The control group included 20 healthy adults out of a blood doner group. The plasma and erythrocytes taken from the blood samples were analyzed immediately. Results. This investigation proved that the application of intensive insulin treatment regime significantly improves total antioxidative plasma capacity as compared to the application of conventional therapy regime. The obtained results showed that the both plasma and lipoproteines apo B MDA increased significantly more in the patients on conventional therapy than in the patients on intensive insulin therapy, most probably due to intensified xanthine oxidase activity. The level of the MDA in fresh erythrocytes did not differ significantly between the groups on intensive and conventional therapy. The level of GSH and catalase activity, however, were significantly reduced in the patients on conventional therapy due to the increased susceptibility to H2O2-induced oxidative stress . Conclusion. The presented study confirmed positive effect of intensive insulin therapy on metabolic control expressed through glycemia level, glycolysed hemoglobine (HbAlc) and fructosamine, as well as through antioxidative/prooxidative homeostasis. This is the confirmation that an adequate treatment choice can prevent numerous diabetes mellitus complications induced by free radicals.

A study of the influence of ultraviolet radiation on di(2-ethylhexyl) phthalate leaching from poly(vinyl chloride) medical devices

The influence of ultraviolet (UV) radiation on the leaching of di(2- -ethylhexyl) phthalate (DEHP) from 8 different parts of plastic medical devices made of poly(vinyl chloride) (PVC) that are used in two important medical procedures (peritoneal dialysis and transfusion) was investigated. The investigation was performed for three different extraction times (6, 15 and 30 days). DEHP determination was realized by gas chromatography–mass spectrometry (GC-EI– –MS). All the investigated samples contained a significant amount of DEHP. The results showed that some of the set for peritoneal dialysis contained DEHP in higher amounts than samples from the transfusion set. All samples of tubing material showed higher concentration levels of DEHP than the coupled bags. Results obtained after UV treatment showed that UV radiation has a certain influence on DEHP leaching from samples of PVC medical devices. The smallest difference was in the case of the quadruple blood bag from the transfusion set (about 73 % remained), while the biggest difference was obtained for the SAG-M transfer bag, also from the transfusion set, where just 25 % of total content of DEHP remained. The results obtained for DEHP leaching from investigated samples by time showed that most of the samples showed significant differences in the amounts of DEHP leached after 6 and 30 days. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 41018

Changing discriminatory and negative attitudes towards mentally ill students

Polje interesovanja i delovanja preventivnog programa koji je u ovom radu prikazan predstavlja diskriminacija mladih sa mentalnim poremećajima. Postoje mnogi praktični načini da se radi na rešavanju problema diskriminacije - kroz reformisanje službi i institucija sistema predstavljanja anti-diskriminacionih politika i zakona, delovanjem putem medija i kroz edukativne programe u sklopu medicinskih ustanovi koje se bave ovom problematikom, za koji smo se mi odlučili. U prvom delu rada određuju se pojmovi stigme i diskriminacije i prikazuje se zastupljenost mentalnih poremećaja kod mladih. U drugom delu opisali smo pilot-program koji je realizovan u jednoj beogradskoj srednjoj školi, predstavili smo razloge za njegovo sprovođenje, način rada, kao i rezultate koje smo dobili.A preventive program presented in this paper is focused on discrimination of the young people with mental disorders. There are many ways to fight this form of discrimination - by reforming services and institutions of the system, recommending and passing anti-discriminatory laws and policies media campaigns, educational courses in relevant medical institutions, the last one being the area we decided to act in. In the first part of the paper the concepts of stigma and discrimination are defined and statistic data on mental disorders among young people are presented. In the second part we described a pilot program realized in a Belgrade high school, presented our reasons for our undertaking, and described the techniques we used, as well as the results we obtained