Polarographic Method Research Articles

Genome‐wide Association Study of Oxidative Phosphorylation in Cocks Semen after Freezing

The biochemical processes associated with the generation of energy (ATP) ‐ oxidative phosphorylation (OXPHOS) and glycolysis ‐ occupy a central place in the vital activity of cells. OXPHOS is the terminal process of cellular respiration (CR). Aim of the study was Genome‐wide Association Study of OXPHOS in cocks sperm after freezing. Semen from 96 cocks was frozen. CR was assessed by the polarographic method. OXPHOS can be evaluated by the reaction CR on adding 2,4‐dinitrophenol (2,4 ‐ DNP) to semen sample. 2,4 ‐ DNP disrupt the proton gradient by carrying protons across a membrane and uncouples proton pumping from ATP synthesis because it carries protons across the inner mitochondrial membrane. As a result it increases respiration rate. If the respiration rate increases – there is good OXPHOS. Sperm motility was evaluated by computer‐assisted semen analysis (CASA) (ArgusSoft, Russia) before and after freezing. The evaluation was carried out using an Axio Imager microscope (Carl Zeiss Microscopy GmbH, Germany). DNA was isolated from sperm samples for genotyping on Gallus Gallus – Affymetrix Axiom®600k Array. Calculations were performed using the PLINK and EMMAX programs. The Genome‐Wide Association Studies (GWAS) was used for the analysis of genomic associations. Results are depicted as ranges, percentages of totals and averages ± SEs. The volume ejaculate varied from 0.4 ml to 1.4 ml, motility before freezing was from 20 to 95% and motility after freezing was from 5 to 80%. The 2.4‐DNP (FSRA) stimulation of respiration after freezing ranged from 1 to 8.09, averaging 1.66±0.114. The high repeatability of the FSRA score across samples suggests the presence of genetic factors, the identification of which can serve as a test for selecting animals with sperm whose quality remains fertile after freezing. 28 potential SNPs associated with FSRA the were found. На 5 хромосоме было найден также блок SNPs (большинство из них significant, 4 последних ‐ suggestive: AX‐76791596 (P‐value=6,20E‐09), AX‐76791535 (P‐value=1,83E‐08), AX‐76791611 (P‐value=1,83E‐08), AX‐76791454 (P‐value=1,87E‐08), AX‐76791629 P‐value=2,11E‐08), AX‐76791570 (P‐value=4,04E‐08), AX‐76791651 (P‐value=5,43E‐08), AX‐76791640 (P‐value=8,84E‐08), AX‐76791553 (P‐value=9,94E‐08), AX‐76791503 (P‐value=1,18E‐07), AX‐76791443 (P‐value=5,49E‐07), AX‐76791439 (P‐value=1,41E‐06), AX‐76791501 (P‐value=1,63E‐06). The significant SNPs found were located in the RAG2 gene. We suggest that the polymorphism in this gene is associated with the selectivity of fertilization, and the efficiency the work is associated with ATP‐dependent remodeling of ATPase subunits. Studies have opened up the possibility of studying the changes in the cells after freezing. Found SNPs markers will be used to select males whose semen is suitable for cryopreservation.

Determination of Lead and Cadmium Concentrations in the Blood of Workers at the Liquid Battery Factory in Baghdad,Applying Differential Pulse Polarography Method.

The concentrations of Pb2+ and Cd2+ in the blood of 30 persons working in the Liquid Battery Factory in Baghdad were measured applying the Differential Pulse Polarography (DPP) method. It was found that for the majority of the blood samples, the Pb2+ concentration valueswere acceptable and within the acceptable natural limits(10-20µg/100ml).Exceptionsare 4 samples which showed higher lead ion concentrations. The infected persons worked at a location with high lead presence in the factory. As for the measured Cd2+ concentrations, the results for all the blood samples showed normal values, within the defined acceptable concentration (5.4µg/100ml). However, onconsidering the other defined acceptableconcentration, as reported in the literature, (3µg/100ml), three workmen were found, to have higher Cadmium ion concentration in their blood. It was also found that, compared with the calibrated DPP results, themeasured Atomic Absorption Spectroscopic (AAS) results showed much higher concentration values and should therefore be not acceptable. The measured concentrationsofboth ionswere independent from the age of the workers. Inspections for the presence of Cu2+ ions in the blood samples failed in detecting any traces of it.

EFFECT OF GABA AND GLUTAMIC ACID DERIVATIVES ON THE FUNCTIONAL ACTIVITY OF LIVER CELL MITOCHONDRIA IN VITRO 147 UNDER CONDITIONS OF OXIDATIVE STRESS

The aim of the study was to study the effect of GABA derivatives on the functional activity of intact and oxidative stress-damaged mitochondria. Isolated mitochondria were obtained by differential centrifugation. Oxidative damage was simulated by incubation with tert-Butylhydroperoxide (200 nmol/ml, 10 min). The studied substances (baclofen, mefebut, neuroglutam, RGPU-238 compound, salifen, tolibut, phenibut, phenotropil) were added to intact and damaged mitochondria (1*10-5 M per 100 μl, 10 min of incubation), the functional state of mitochondria was studied using a polarographic method. It was revealed that salifen and phenotropil had a pronounced protective effect on the respiratory complexes of the electron transport chain.

Measuring the levels of Zn, Cu, Pb and Cd via the polarography method in fermentative pickled cucumbers purchased from Tehran market, Iran

Pickled cucumber is frequently consumed by Iranians. According to the production process, there are two forms of pickled cucumber including industrial and fermentative. There is not an appropriate monitoring system available for the production of the latter form; therefore, high levels of heavy metals might be present in this type of pickled cucumber. Accordingly, so the levels of cadmium, zinc, lead and copper were measured in fermentative pickled cucumbers obtained from the Tehran market via the polarographic method. Polarography is a subclass of voltammetry where the working electrode is a dropping mercury electrode (DME) or a static mercury drop electrode (SMDE), which are useful for their wide cathodic ranges and renewable surfaces. Fifty different samples of pickled cucumbers were purchased from the market. Of each sample, dry ashes were produced. Measurement was repeated three times and the acquired data was then analyzed. The mean levels of zinc and copper in the evaluated samples were significantly lower than the standard limits respectively presented by the EOS and Codex (P value<0.001) while the mean level of cadmium and lead was slightly higher than the standard limit established by Codex with no significant differences observed (P values=0.450 and 0.246, respectively).

Synthesis, toxicity evaluation and determination of possible mechanisms of antimicrobial effect of arabinogalactane-capped selenium nanoparticles

BackgroundThe elemental selenium nanoparticles (Se0NPs) find application in biology and medicine due to wide spectrum of their biological activity combined with low toxicity. For instance, Se0NPs are promising antimicrobial agents for plant treatment against the bacterial phytopathogen Clavibacter michiganensis sepedonicus (Cms). Careful characterization of possible mechanisms of antimicrobial action of Se0NPs as well as the assessment of their biosafety for plant and animal organisms represents urgent challenge. MethodsAG-stabilized Se0NPs (AG/Se0NPs) were synthesized by oxidation of selenide-anions by molecular oxygen dissolved in the reaction medium in the presence of AG macromolecules. The antimicrobial activity of AG/Se0NPs against Cms was investigated both by observing the change in optical density of bacterial suspension and directly evaluating the cell death using fluorescent microscopy with propidium iodide staining. The effect of AG/Se0NPs on the dehydrogenase activity was studied by determination of Cms enzymes ability to reduce colorless TTC to formazan. The effect of AG/Se0NPs nanocomposite on the respiration rate of Cms cells was examined by polarographic method. For qualitative visualization of the potential on the inner membrane of Cms mesosomes, the potential-dependent TMRM dye and fluorescence microscopy were used. The toxicity of the AG/Se0NPs was investigated on white mice by the Litchfield-Wilcoxon method. The effect of AG/Se0NPs on plant organisms (potato plants) was studied on healthy and Cms-infected plants by determining the level of chlorophyll and lipid peroxidation products (LPO) in their leaves when treated with nanoparticles. ResultsSpherical Se° nanoparticles with an average size of 94 nm were obtained using the stabilizing potential of AG. It was found that these nanoparticles exhibited the pronounced (up to 60 %) bacteriostatic action (in 6.25 μg/mL concentration) against the bacterial phytopathogen Cms. It was shown and experimentally confirmed for the first time that the probable causes of the bacteriostatic action of AG/Se°NPs against Cms are non-reversible inhibition of Cms cell respiration, a decrease of the transmembrane potential with a change in the cell wall permeability for H+ protons and a decrease in their dehydrogenase activity. It was revealed that the treatment of healthy and Cms-infected potato plants with an aqueous solution of AG/Se°NPs involved no significant changes in the content of LPO and negative effect on the chlorophyll content, thus contributing to the saving of these values at the level of control intact plants. ConclusionUsing a complex of complementary methods, we have found that antimicrobial activity of AG/Se0NPs is apparently due to their ability to inhibit the dehydrogenase activity of Cms cells, as well as to disrupt the integrity of the cell membrane, resulting in a decrease of transmembrane potential and reduction of cellular respiration. The antimicrobial and antibiofilm activity of AG/Se0NPs, together with their nontoxicity and safety for plant and animal organisms, determine the prospects for design of AG/Se0NPs-based drugs for the rehabilitation of plants from the Cms.

Antioxidant Capacity and Quality of Human Milk and Infant Formula Determined by Direct Current Polarography

Antioxidants present in infant food contribute to its nutritive value and provide protection from oxidative damage. Here, a direct current polarographic method, based on a decrease of anodic current from the hydroxoperhydroxo-mercury(II) complex (HPMC) formed at a mercury dropping electrode at its potential of dissolution, was used to determine the total antioxidant capacity (TAC) of infant formulas, human milk collected from mothers of full-term and preterm infants, human milk supplemented with fortifier, and cow milk. TAC of milk samples and infant formula correlated with protein content measured by the Bradford method (Pearson correlation coefficient 0.605, p<0.001), while TAC of human milk correlated with content of free thiol groups measured by the Ellman method (0.779, p<0.001). The results obtained showed that, in contrast to the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, HPMC enables specific insight into the quality of infant milk food which reflects the amounts of free thiol groups and protein content. The significant contribution of milk proteins and the most prevalent amino acids, particularly cysteine, arginine, and phenylalanine, to TAC was shown. Thus, the HPMC method might be useful in monitoring the quality of infant formulas and human milk for preterm infants before and after supplementation with fortifier.

Analyzing sensitivity of the energy metabolism in the tissues of the heart, liver, kidney, and blood lymphocytes in rats to the effect of local vibration and pharmacological protection by a succinate-containing antihypoxanth

Introduction. Modern technological processes that generate ultra- and infrasound, electromagnetic, vibration-noise radiation significantly exceed the background effects and inevitably create an unfavorable technogenic load on the human body. A special place is occupied by vibration, primarily associated with such professional groups as mining enterprises, gold and diamond processing plants, aircraft plants, thermal power plants and hydroelectric power plants, and aluminum industry enterprises. Vibration exposure leads to a number of biochemical disorders in the homeostasis system. Mitochondrial dysfunctions are among the leading elements in the hierarchy of pathogenesis of many pathological syndromes and diseases. The aim of the study was an experimental analysis of tissue-specific features of the myocardium, kidneys, liver energy production system activity as well as the enzyme status of rat lymphocytes in relation to the activity of succinate dehydrogenase (SDH) on the background of 7 episodes of local vibration with a frequency of 27-30 Hz for 90 minutes daily before and after protection with succinate-containing antihypoxant "Yantar-cardio" at a dose of 100 mg/kg/day. Materials and methods. The study of the energy-dependent reactions of the native mitochondria of the organs was carried out by the polarographic method using a closed Clark-type membrane electrode. The activity of SDH of rat blood lymphocytes was studied by a modified method of quantitative cytochemical analysis. Results. Functional rearrangement in the respiratory chain (RC) of the mitochondria confirmed the NAD-dependent site's inhibition and activation of the oxidation system of endogenous succinic acid, most pronounced in the myocardial tissue. On the vibration background, the specific SDH activity of lymphocytes (Q) significantly increased by 52%, and the variability (V) - by three times. The use of "Yantar-cardio" limited the growth rate of endogenous respiration of the most significant in the heart (70%, p&lt;0.05), restored oxidative and conjugating activity NAD-dependent link of RC, improve the structure and condition of the cell population of lymphocytes based on their energy status and warned the mismatch of the leading parameters of the population variability of the cellular pool of blood lymphocytes in experimental animals. Conclusions. The intensity of vibration-mediated bioenergetic hypoxia in the form of inhibition of the NAD-dependent link of the respiratory chain and activation of the endogenous succinic acid oxidation system is tissue-specific and is most pronounced in the myocardial tissue. The succinic acid oxidation system is highly sensitive to vibration effects and a pharmacological drug that supports the function of RC under conditions of the stress of the homeostatic functions of tissues involved in the pathological process.

Effect of per os administration of dihydroquercetin aqueous form on energy exchange in blood lymphocytes of rats with experimental cardiomyopathy

Cardiomyopathies are among the most severe myocardial pathologies, which are characterized by resistance to therapy and high mortality due to increasing heart failure and arrhythmia. Cardiomyocyte pathological changes upon cardiomyopathies are associated with mitochondrial dysfunction, leading to excessive formation of reactive oxygen species and the development of oxidative stress. In this regard, the study of the therapeutic potential of antioxidants in cardiomyopathies, as well as the mechanisms of their action on the functioning of mitochondria, is relevant and of high practical importance. The aim of this study was to determine the effect of oral 14-day administration of dihydroquercetin in a water-soluble form (DHQWF) on the activity of the key marker of mitochondrial respiration [succinate dehydrogenase (SDH)] and the cytoplasmic marker of glycolysis [lactate dehydrogenase (LDH)] in blood lymphocytes, as well as on the serum level of lipid peroxidation (LPO) in control rats and rats with experimental cardiomyopathy. Material and methods. Adult male Wistar rats (body weight 220-240 g) were used for the study. Isoprenaline hydrochloride was used to induce cardiomyopathy (IIC) in animals (twice subcutaneous injection at a dose of 150 mg/kg body weight, with a break of 24 hours). DHQ-WF was added to the drinking water for 14 days at the dose of 15 or 30 mg/kg body weight. SDH and LDH activity in lymphocytes was measured using a highly sensitive cytobiochemical method on a blood smear according to the reduction of nitrotetrazolium blue chloride to diformazan of dark blue color. The content of malone dialdehyde (MDA) in the blood serum, heart and liver mitochondria was determined spectrophotometrically using thiobarbituric acid. Mitochondria were isolated from rat tissues by the conventional method of differential centrifugation. Mitochondrial respiration was recorded using a polarographic method. Results. Experimental cardiomyopathy in rats was accompanied by a twofold increase in blood serum MDA level, as well as by a significant increase in SDH and LDH activity in blood lymphocytes. The oral administration of DHQ-WF in cardiomyopathy at a dose of 15 mg/kg body weight led to a significant decrease in serum MDA level, but did not reduce the activity of SDH and LDH in blood lymphocytes, compared with animals with cardiomyopathy that did not receive DHQ-WF. In the control group of animals, the use of DHQ-WF at a dose of 15 mg/kg body weight significantly increased blood lymphocyte LDH activity, but did not have a statistically significant effect on SDH activity and the parameters of mitochondrial respiration and oxidative phosphorylation, the level of MDA in heart and liver mitochondria. Increasing the dose of DHQ-WF administered to 30 mg/kg had less effect on changes in these parameters in control animals. Conclusion. The data obtained indicate that in experimental cardiomyopathy in rats, the course application of DHQ-WF at a dose of 15 mg/kg of body weight acts as an effective antioxidant that prevents the development of lipid peroxidation in blood serum, and can modulate energy metabolism towards the enhancement of glycolysis in blood lymphocytes in control animals.

Electroanalytical Investigation of Nimesulide by Differential Pulse Polarography: Method Validation

Nimesulide is a new non-steroidal anti-inflammatory analgesic drug. In the last eight decades, voltammetric methods has become a popular tool for the study of electrochemical reactions. the electroanalytical behavior of nimesulide using differential pulse polarography techniques. Using this technique, the effect of increasing concentration of nimesulide, scan rate and repetitive scanning on the peak height (Ip) and peak potential (Ep) of each compound will be investigated. The general procedure can be used to obtain DPP Polarogram of nimesulide. A study was carried out using optimum parameters to observe a relationship between Ip and concentration of nimesulide. Precision and accuracy of the method is studied. The developed differential pulse polarography method can be applied for calibration and determination of nimesulide in tablets.

A Rapid Mercury Droplet Electrode Polarography Method for Determination of Blood Lead Level in Lead Poisoned People.

Lead is a hazardous heavy metal, which causes many problems in the human body. Unfortunately, recent reports showed that smugglers and opium sellers add lead to drugs during the production procedure in order to increase its weight and cost. The aim of this study was development of a rapid and accurate method for measurement of blood lead levels (BLL) in the oral and inhaled opiate abuser people. BLL in samples obtained from the oral and inhaled opium addicted patients referring to Sina Hospital in Tabriz, Iran, during 2017 was compared with healthy control group (N=15). The wet digestion method was used to prepare whole blood and Mercury Droplet Electrode Polarography (MDEP) method was utilized for measurement of the lead content of digested samples. Results showed that there were significant differences between the BLL of samples obtained from oral (17.12±74.61 μg/dL, p<0.0003) and inhaled (19.33±2.257 μg/dL, p<0.0001) opium addicted groups in comparison with healthy control group (4.669±0.3367 μg/dL). Based on the results of this study it was observed that BLL in opium addicted people needs to be measured as soon as possible. Furthermore, screening of blood lead concentrations in opium-addicted people with a rapid and accurate MDEP method is very necessary and important.

History and development of analytical chemistry at Charles University before 1920

The article is dedicated to the centenary of the establishment of the independent Faculty of Science of the Charles University; in particular, it provides an overview of the history of analytical chemistry at this university from its founding in 1348 to 1920. At the beginning of the article, the history of the Charles University with a focus on sciences is briefed and the most important representatives at the Charles University are recalled (Bernard Bolzano, Albert Einstein, Ernst Mach). Despite the fact that analytical chemistry has been taught as a separate discipline at the Charles University since the middle of the 19th century, its roots can be traced back to the early years of the Charles University’s existence, i.e., six centuries before the Faculty of Science of the university was established. Therefore, the story of analytical chemistry at the Charles University represents an important chapter in the history of chemistry in the Czech Lands. The first specific mentions of analysis at the Charles University can be found at the beginning of the 17th century, when university theses dealt with the mental analysis of chemical problems. During the 17th and 18th century, as at other European universities, analytical chemistry emerged as an important auxiliary science at the Faculty of Medicine. Here the Founding Fathers included especially Jan Marek Marci of Kronland (1595–1667), discoverer of the separation of white light in a prism eighteen years sooner than Isaac Newton. Professor Jan Antonin Scrinci (1697–1773) established uninterrupted teaching of chemistry at the Charles University. He focused mainly on the analysis of mineral waters, and therefore, the article provides the first detailed evaluation of his chemical publications. Next, the successful development of analytical chemistry at the Charles University is described by reconstructing the line of succession of the foremost representatives of analytical chemistry at the University. The attention is drawn to the aspects of analytical chemistry present in their publications of that time. The rapid development of chemistry in the second half of the 19th century culminated at the Charles University in the person of Bohuslav Brauner (1855–1935), Mendeleev’s close friend and one of the most important Czech chemist. Thanks to him, an independent Faculty of Science was finally established in 1920, which, among other things, created the conditions that later led to awarding of the Nobel Prize to Professor Jaroslav Heyrovský for the discovery and development of polarographic methods of analysis.

Differential Pulse Polarography Method for the Determination of Trace Fe, Ni, Pb, Zn, Se and Cu in Black Tea Leaves

In this work a new and simple polarographic method has been established for the determination of trace elements present in tea. After digestion with acids, tea samples were analyzed using various electrolytes such as acetate and ammonia at different pH values in the presence or absence of EDTA. Thus, it was possible tochoosethe best medium for the determination of6 trace elements in one tea sample. Polarographic peaks of copper and iron could be separated in HAc at about pH =7 in the presence of EDTA and their quantities were determined. Ni and Zn peaks could be separated and determined in ammonia buffer at about pH= 10. Lead could be determined at pH= 2HAc electrolyte. Selenite, was determined from its hydrogen catalytic peak in KCl, pH= 2 medium in the presence of Mo (VI). The LOD was found as 2.4x10-7 for instead of (S/N=3).The trace element ranges in black tea were found as, Fe 35 μg/g, Cu 45 μg/g, Ni 19 μg/g, Zn 22 μg/g, Pb 28 μg/g and Se 77 μg/g.

Determination of Methimazole in Pharmaceutical Preparation and Human Serum by Square Wave and Differential Pulse Polarographic Methods

Objectives: In this study, the polarographic behaviour of methimazole was studied using cyclic, square wave and differential pulse polarographic methods. Methods: The influence of several variables (including nature of the buffer, concentration, scan rate, drop size, etc.) was examined in square wave and differential pulse polarographic methods for methimazole. The best square wave and differential pulse polarographic responses were obtained in 0.1 M sulfuric acid. The peak currents were measured with a static mercury drop electrode at 0.10 V versus Ag/AgCl. Results: The linearity was established over the concentration range of 5-80 mg/mLfor both methods in supporting electrolyte and human serum. The methods were validated and applied to the determination of methimazole in a commercial tablet. There was no significant differences between the results obtained by square wave and differential pulse polarographic methods. Square wave and differential pulse polarographic methods are also available and applicable for the determination of mentioned substance in human serum. No electroactive interferences from the endogenous substances were found in the serum samples. Mean recovery was 99.9%. Conclusion: They were concluded that the developed methods were accurate, sensitive, precise, reproducible and useful for the quality control of methimazole in pharmaceuticals and spiked serum.

The Use of Algae’s Photosynthetic Activity in Toxicity Assessment with the Purpose of Creating Portable Devices

The choice of test organisms and test reactions to be used in biotesting devices for wastewater toxicity, including portable ones, is caused by such factors as ease of cultivation and keeping test organisms in the laboratory, relatively high sensitivity to toxic substances, possibility of instrumental recording of physiological indicators used as test reactions on toxicity, a short time from the beginning of the toxicant action to the appearance of changes in the test reaction. Based on these criteria, we can assume that algae are a fairly convenient test organism for instrumental methods of biotesting since they have the a great deal advantages. Purpose. To find the best options for assessing the photosynthetic activity of algae. Methods. The polarography method. Results. The authors have analyzed dependence of the main characteristics of the sensor on the structure of the diffusion layer and temperature and have found out that the optimal choice of the structure can be made depending on the biological object and experimental conditions. The research has shown that test reactions characterizing physiological state of algae are very diverse. This facilitates their choice for the purposes of instrumental toxicity biotesting, including biotesting toxicity of wastewater with portable instruments. Analysis of the experimental data has shown that it is possible to achieve the difference between concentrations of dissolved oxygen in a liquid culture before and after the exposure of the algae of 1-8 mg / l in a sufficiently short period of time by adjusting the density of algal cultures and light intensity. This indicates the fact that in principle it is possible to quantify photosynthetic activity of algae at short time intervals when exposed to light. Conclusions. The most promising method for assessing the photosynthetic activity of algae is the polarography method, which makes it possible to develop a portable instrument for wastewater toxicity biotesting.

Concentration Dependences of Molecular Oxygen and Hydrogen in Aqueous Solutions

The concentration dependences of molecular oxygen and hydrogen in aqueous solutions are studied with multiple dilutions and turbulent stirring accompanying the dilution procedure. Deionized water was saturated with molecular hydrogen and molecular oxygen by bubbling. The gas concentration was measured by polarographic methods. Upon reaching a specific number of dilutions, the concentration of impurities in the aqueous solution ceases to depend on the number of dilutions. The ability to observe this effect is determined by the sensitivity of the measurement method. The composition of the aqueous solutions can change under conditions of mechanical action. Mixing stimulates the capture of molecular oxygen from the atmosphere. The effect is more pronounced with turbulent stirring than with laminar.

Determination of Vitamin B12 Using Differential Pulse Polarography

Vitamin B12 is a type of vitamin also known by the name cobalamin. B12 is involved in many metabolism activities, including DNA synthesis, nervous system, red blood formation and immune system. Therefore, we chose the Differential Pulse Polarography (DPP) method is that has a high sensitivity for the determination of vitamin B12. This determination was possible with cobalt present in vitamin B12 structure. Since Co(III) is formed from the oxidation of the vitamin, its polarographic behavior had to be determined in various electrolytes such as acetate, borate, phosphate and ammonia. The polarograms of Co(III) were taken in these electrolytes in which 1.0 M NH3/ (pH = 9.8) and 1.0 M AcOH/AcO- (pH = 4.0) were found as the most suitable electrolytes. This method was successfully applied vitamin of B12 determination in a 1 mL ampoule with high precision. The LOD was found as 3.7 × 10-7 for instead of (S/N = 3). Besides Co(III), interference effects of Zn(II), Ni(II), Cr(III), Fe(III), Cu(II), Cd(II) and Se(IV) were also studied. It was found that only Zn(II) peak had an overlap Co(III) peak in ammonium buffer. This problem could be solved by working in 1.0 M AcOH/AcO- (pH = 4.0) buffer. B12, which is 1000 μg in 1 mL vitamin ampoule, was found for 4 measurements as 999 ± 15 μg as a result of 95% confidence interval.

Clinical Evaluation of the Effectiveness of the Use of Laser Photodynamic Therapy in Complex Treatment of Periodontal Diseases

The results of a study of the effectiveness of laser photodynamic therapy in complex treatment of periodontal diseases have been presented. Dental indices OHI-S, SBI, PMA, PI and the polarography method have been used as clinical criteria for assessing the state of periodontal tissues.

Determination of Sulfite in Wine Using Differential Pulse Polarography

Sulfite determination plays an important role, since it is used in some food stuff as protecting agent. It is a known fact that higher values of sulfite in foods will create some health problems. Thus, its accurate determination has a vital importance. In this investigation a new and simple DP polarographic method is established for the determination of sulfite. The polarographic peak of sulfite was used for its determination. The polarograms of sulfite were taken in various electrolytes and pH values in the presence or absence of wine in order to find the best working conditions. It was possible to determine 2 × 10–6 M sulfite in pH 4 Hac–NaAc electrolyte. This method is applied to various wines and it was possible to determine the free and bound sulfite. The results obtained were also compared with an iodometric method used in TSE (Turkish standardization Institute).

Development and validation of a differential pulse polarography method for determination of total vitamin C and dehydroascorbic acid contents in foods

The objective of the study was to develop a new method for the determination of total vitamin C and dehydroascorbic acid contents in food using the differential pulse polarography technique, and to compare achieved results to those obtained with the proposed reference method applying HPLC with spectrophotometric detection. Dithiothreitol was used to reduce dehydroascorbic acid into l-ascorbic acid. Interference due to the presence of dithiothreitol during polarographic determination of l-ascorbic acid was efficiently eliminated by clarification of the sample solution with Carrez reagent. Validation of the polarographic method indicates its usefulness for the analysis of foods products that do not contain isoascorbic acid. The coefficient of variation for the analysis of l-ascorbic acid and total vitamin C content ranges from 1.86% to 6.98%, Horrat values from 0.41 to 0.89 and average recovery of l-ascorbic acid ranges from 98% to 104%. Results obtained using the developed method are characterised by high compatibility with those obtained with the HPLC reference method, indicating equivalence of both methods, and in conclusion, the method was deemed fit for purpose for measuring total vitamin C and dehydroascorbic acid in foods.

Cellular mechanisms of hypoxia development in the tissues of experimental animals under varying characteristics of vibration exposure

The aim of the work was to study the primary bioenergetic mechanisms of hypoxia formation in the myocardial tissue of experimental animals depending on the differentiated physical characteristics of vibration (frequency and duration) and their combination. The study of the functional states of native mitochondria in the composition of the tissue homogenate was carried out using the polarographic method and a galvanic-type closed-oxygen sensor in a 1-ml thermostatic cuvette in a salt incubation medium. The metabolic states of the mitochondria of the myocardium of experimental animals were modeled in vitro during the oxidation of endogenous substrates (before and after the administration of inhibitors of different links of the respiratory chain), with varying exogenous energy substrates (before and after the introduction of 2,4-DNP into the cell). In order to ensure synchronism of measurements in a short time, an incomplete cycle of metabolic states “endogenous respiration → rest → activity” was used. The results of multiple comparisons of variations in kinetic parameters revealed a reliable but multidirectional effect of the frequency of vibration on the rate of oxidation of substrates of the mitochondria of the heart of rabbits in different metabolic states. A change in the duration of exposure to vibration showed an increase in the oxidation rate of endogenous substrates and succinic acid at rest to 21–56 sessions by 17% and 24. 4%, respectively, while the oxidation rate of glutamate decreased to 56 sessions by 24. 5%. Comparison of the general variability of kinetic parameters with a combination of frequency and duration of vibration at different levels of variation showed that it was the interaction of factors that made the most important and significant contribution to the intergroup variability of oxidation rates of endogenous and exogenous substrates, identifying signs of the formation of bioenergetic hypoxia and allowing analysis of the primary physical transformation phenomena in the biological effect.