Asya Tsanova - Academia.edu (original) (raw)
Papers by Asya Tsanova
PubMed, 2012
The aim of the present study was to estimate the lung surfactant maturity by analyses of gastral ... more The aim of the present study was to estimate the lung surfactant maturity by analyses of gastral aspirates (GA) from prematurely born and full-term infants. A biochemical analysis of the protein and lipid content in GA from the children groups tested was made. By thin-layer chromatography the individual phospholipids components in GA samples from prematurely born and full-term children were detected. In addition, by using the pending drop method the surface characteristics (equilibrium, maximal and minimal surface tension values) were determined. Our results showed an increase in the phospholipid and the protein concentrations in GA during pregnancy progress as well as significant differences in the individual phospholipids profile of the aspirates from prematurely born and full-term children. In case of surface characteristics a highest difference was observed for the minimal surface tension values (gammamin, m/Nm); while in the full-term children a lower surface tension was determined, in the prematurely born children significant higher values were reached, which define gammamin as the most informative from the parameters studied. Our results could find application into the clinical practice for fast surfactant maturity diagnostics in prematurely born children regarding lifesaving therapy with exogenous surfactants administration.
PubMed, May 24, 2013
Background: The optimal approach to detection of surfactant deficiency in the prematurely born in... more Background: The optimal approach to detection of surfactant deficiency in the prematurely born infants at birth remains unclear and the decision to apply exogenous surfactant is based mainly on the development of clinical and radiological signs of neonatal respiratory distress syndrome (NRDS). Objectives: We studied the biochemical and biophysical properties of gastric aspirates (GA) from prematurely born infants with NRDS and healthy full term infants with an aim to find an approachable method for assessment of surfactant maturity at birth. Material and methods: Forty-seven newborn infants divided into two groups were enrolled in the study. The first group comprised 34 healthy infants born at term (after 37 weeks of gestation). The second group included 13 premature infants (aged from 26 to 32 weeks of gestation) developing clinical signs of NRDS for which they were treated by assisted ventilation and exogenous surfactant. A biochemical analysis of the protein and lipid content of GA collected at birth was performed. The fatty acid composition of the GA samples was determined by Gas Chromatography-Mass Selective Detector (GS-MSD) analysis. The surface characteristics (equilibrium, maximal and minimal surface tension values) of the GA samples were measured by using the pending drop method. Data were compared between the groups by using Student's t test or Mann-Whitney analysis. Values were considered significantly different if the p value was = 0.05. Results: The mean phospholipids' concentration in GA of the premature infants was lower (295.7 µg / ml vs. 374.5 µg / ml) than in the term infants and the mean protein content was less in GA of the premature babies than the term newborns (574.5 µg / ml vs. 641.5 µg / ml). The measurement of dynamic surface characteristics of GA showed significantly higher mean values of the minimal surface tension (γmin) in the premature infants - 20.5 m / Nm compared to the term babies - 12.3 mN/m (p < 0,01). There was no difference between the equilibrium surface tensions (38 mN/m vs. 38 mN/m) of both groups; The mean values of maximal surface tension (?max) in GA did not differ significantly between the groups (50.1 mN/m vs. 48.5 mN/m). Conclusion: Our findings revealed lower phospholipids' and protein concentrations in the GA at birth from premature infants as compared to the healthy term infants. The dynamic surface characteristics of GA had significant differences between the two groups, the minimal surface tension being the most important parameter for evaluation of surfactant maturity. It could be used in the clinical practice for fast surfactant's assessment in the premature infants in regard to administration of exogenous surfactant.
The Journal of Membrane Biology, Dec 12, 2015
During the last decades opioid peptides, like enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are subject t... more During the last decades opioid peptides, like enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are subject to extensive studies due to their antinociceptive action in organism. According to the membrane catalysis theory, in order to adopt a proper conformation for binding to their receptors, opioid peptides interact with the lipid phase of the membrane receptor surrounding. With this regard, the aim of the present work was to study the effects of synthetic leucine-enkephalin and leucine-enkephalinamide on surface characteristics and morphology of lipid monolayers, composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, sphingomyelin, and cholesterol alone and with their mixtures. The lipids were chosen to represent a model of a membrane raft, since it is known that G-protein-coupled receptors, including opioid receptors, are located preferably in membrane rafts. By using Langmuir's monolayer method, the change in surface pressure of the model membranes before and after the addition of the synthetic enkephalins was studied, and the compressional moduli of the lipids and lipid-peptides monolayers were determined. In addition, by Brewster angle microscopy, the surface morphology of the lipid monolayers alone and after the injection of both enkephalins was monitored. Our results showed that both leucine-enkephalins affected the lipid monolayers surface characteristics, and led to an increase in surface density of the mixed surface lipids/ enkephalins films at loose lipid packing. This effect was more pronounced for the enkephalinamide, suggesting a different mechanism of interaction for the amidated enkephalin with the lipid phase, as compared to leucineenkephalin.
Enkephalins are pentapeptides (Tyr-Gly-Gly-Phe-Met/Leu) with proven antinociceptic action in orga... more Enkephalins are pentapeptides (Tyr-Gly-Gly-Phe-Met/Leu) with proven antinociceptic action in organism. They are neurotransmitters found in the central nervous system, which interact with opioid receptors in order to play their biological action. Enkephalin receptors belong to G-protein coupled receptors. It is known that these receptors are located in membrane rafts. Moreover, it is believed that in order to achieve conformation for binding to opioid receptors enkephalins interact with the lipid phase of the membranes. In the present work by using Langmuir's monolayer technique in combination with Wilhelmy's method for measuring the surface pressure, the interaction between synthetic enkephalins and monolayers composed of the raft lipids palmitoyl oleoyl phosphatidyl choline, sphingomyelin, cholesterol, as well as their double and triple mixtures was studied. From the pressure-area isotherm measured, the compressional modulus of the lipids and lipids-peptides monolayers was ...
Phospholipids in the composition of alveolar surfactant play a crucial role for its optimal funct... more Phospholipids in the composition of alveolar surfactant play a crucial role for its optimal functioning. Studies on fatty acid composition of individual phospholipid components of alveolar surfactant show that there is some correlation between the fatty acid profile and normal biophysical function of alveolar surfactant. So far the fatty acid profile has been determined in alveolar surfactant only. For the first time in the present study fatty acid analysis of lipids in gastric aspirates from children with Neonatal Respiratory Distress Syndrome (NRDS), premature infants and full-term babies was made. Qualitative and semi-quantitative analysis of fatty acids in gastric aspirate samples was made by Gas Chromatography-Mass Selective Detector. The results show that saturated/unsaturated fatty acids ratio is highest in the group of full-term infants. Moreover, the most common of all fatty acids is the saturated palmitic (C16: 0). Based on these and future studies we expect a new method b...
Acta Medica Bulgarica, 2010
European Respiratory Journal, 2014
Aim: To identify changes in the biochemical and biophysical behavior of lung surfactant (LS) in t... more Aim: To identify changes in the biochemical and biophysical behavior of lung surfactant (LS) in the unventilated and ventilated lung during surgery in patients with nonsmall cells lung cancer (NSCLC). The relationship between the surfactant changes and complications was examined. Material and Methods: In prospective study we included 32 patients (SG) with NSCLC and a control group(CG) of 29 patients without cancer. Surgery was performed under general anesthesia and a double lumen tube intubation. In both groups we performed bronchoalveolar lavage (BAL): A. From the operated (nonventilated) lung after intubation and before reventilation; B. From ventilated lung after intubation and at the end of anestesia. Biochemical analysis: the amount of phospholipids, cholesterol and proteins. Biophysical analysis: the equilibrium surface tension(γ eq ) and dynamic characteristics of monolayers (minimal surface tension γ min , maximal surface tension, γ max ). Results: In SG the amount of LS pho...
BANGYOZOVA, M., E. LONTOVA, A. TSANOVA, A. JORDANOVA, Y. YAMAKOVA, R. PETKOV and Z. LALCHEV, 2014... more BANGYOZOVA, M., E. LONTOVA, A. TSANOVA, A. JORDANOVA, Y. YAMAKOVA, R. PETKOV and Z. LALCHEV, 2014. In vitro analysis of broncho-alveolar lavage from a patient with pulmonary alveolar proteinosis. Bulg. J. Agric. Sci., Supplement 1: 18–23 Pulmonary alveolar proteinosis (PAP) is a heterogenous disorder of genetic or acquired etiologies characterized by intraalveolar accumulation of lipoproteinaceous material. The clinical course of the disease is variable, ranging from spontaneous remission to respiratory failure. The aim of the present study was to compare the biochemical and biophysical characteristics of broncho-alveolar lavage (BAL) from a patient with PAP, during the whole lung lavage (WLL) taken after each stage of the procedure. For this purpose biochemical and biophysical analysis of the clinical samples were made. The phospholipids (PLs) and the proteins concentrations of the samples were measured. For determination of protein content in broncho-alveolar lavage samples Lowry ...
Biological Markers in Fundamental and Clinical Medicine (collection of abstracts), 2019
SPECIFIC SURFACTANT PROTEINS AS CLINICAL MARKERS FOR LUNG MATURITY IN RISK NEWBORNS
The Journal of Membrane Biology, 2015
During the last decades opioid peptides, like enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are subject t... more During the last decades opioid peptides, like enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are subject to extensive studies due to their antinociceptive action in organism. According to the membrane catalysis theory, in order to adopt a proper conformation for binding to their receptors, opioid peptides interact with the lipid phase of the membrane receptor surrounding. With this regard, the aim of the present work was to study the effects of synthetic leucine-enkephalin and leucine-enkephalinamide on surface characteristics and morphology of lipid monolayers, composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, sphingomyelin, and cholesterol alone and with their mixtures. The lipids were chosen to represent a model of a membrane raft, since it is known that G-protein-coupled receptors, including opioid receptors, are located preferably in membrane rafts. By using Langmuir's monolayer method, the change in surface pressure of the model membranes before and after the addition of the synthetic enkephalins was studied, and the compressional moduli of the lipids and lipid-peptides monolayers were determined. In addition, by Brewster angle microscopy, the surface morphology of the lipid monolayers alone and after the injection of both enkephalins was monitored. Our results showed that both leucine-enkephalins affected the lipid monolayers surface characteristics, and led to an increase in surface density of the mixed surface lipids/ enkephalins films at loose lipid packing. This effect was more pronounced for the enkephalinamide, suggesting a different mechanism of interaction for the amidated enkephalin with the lipid phase, as compared to leucineenkephalin.
Akusherstvo i ginekologii͡a, 2012
The aim of the present study was to estimate the lung surfactant maturity by analyses of gastral ... more The aim of the present study was to estimate the lung surfactant maturity by analyses of gastral aspirates (GA) from prematurely born and full-term infants. A biochemical analysis of the protein and lipid content in GA from the children groups tested was made. By thin-layer chromatography the individual phospholipids components in GA samples from prematurely born and full-term children were detected. In addition, by using the pending drop method the surface characteristics (equilibrium, maximal and minimal surface tension values) were determined. Our results showed an increase in the phospholipid and the protein concentrations in GA during pregnancy progress as well as significant differences in the individual phospholipids profile of the aspirates from prematurely born and full-term children. In case of surface characteristics a highest difference was observed for the minimal surface tension values (gammamin, m/Nm); while in the full-term children a lower surface tension was determ...
Biotechnology & Biotechnological Equipment, 2009
Using Langmuir's monolayer technique, surface behaviour and the interaction between a synthetic a... more Using Langmuir's monolayer technique, surface behaviour and the interaction between a synthetic analogue of endogenous neuropeptide Methionine-enkephalin (Met-enk) and zwitterionic dimyristoylphosphatidylcholine (DMPC), and the negatively charged dimyristoylphosphatidylglycerol (DMPG) at air/water interface are studied. By using the Wilhelmy method, surface tension (γ, mN/m) changes (after injection of the peptide under the interface) of DMPG and DMPC monolayers as a function of time at given molecular area are detected. The decrease in γ values shows that there is a strong penetration effect of Metenk molecules into the monolayers. The comparison of the interaction between the hydrophobic pentapeptide and both phospholipid monolayers shows that the enkephalin interacts similarly with DMPG and DMPC molecules, and that the ability of Met-enk to penetrate correlates with the given surface area per lipid molecule. Based on the results obtained we suggest that in case of liquid-expanded monolayers the electrostatic attraction facilitates the interaction between the neuropeptide and the negatively charged phospholipids (DMPG), while at more compact ordering of lipid molecules the penetration of the enkephalin is preliminary due to hydrophobic interactions.
Amino Acids, 2013
Enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are opioid peptides with proven antinociceptive action in o... more Enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are opioid peptides with proven antinociceptive action in organism. They interact with opioid receptors belonging to G-protein coupled receptor superfamily. It is known that these receptors are located preferably in membrane rafts composed mainly of sphingomyelin (Sm), cholesterol (Cho), and phosphatidylcholine. In the present work, using Langmuir's monolayer technique in combination with Wilhelmy's method for measuring the surface pressure, the interaction of synthetic methionineenkephalin and its amidated derivative with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), Sm, and Cho, as well as with their double and triple mixtures, was studied. From the pressure/area isotherms measured, the compressional moduli of the lipids and lipid-peptide monolayers were determined. Our results showed that the addition of the synthetic enkephalins to the monolayers studied led to change in the lipid monolayers characteristics, which was more evident in enkephalinamide case. In addition, using Brewster angle microscopy (BAM), the surface morphology of the lipid monolayers, before and after the injection of both enkephalins, was determined. The BAM images showed an increase in surface density of the mixed surface lipids/enkephalins films, especially with double and triple component lipid mixtures. This effect was more pronounced for the enkephalinamide as well. These observations showed that there was an interaction between the peptides and the raft-forming lipids, which was stronger for the amidated peptide, suggesting a difference in folding of both enkephalins. Our research demonstrates the potential of lipid monolayers for elegant and simple membrane models to study lipid-peptide interactions at the plane of biomembranes.
Amino Acids, 2010
Using Langmuir&amp;amp;amp;#39;s monolayer technique, the surface behavior and the intera... more Using Langmuir&amp;amp;amp;#39;s monolayer technique, the surface behavior and the interaction of the synthetic neuropeptide methionine-enkephalin (Met-enk) and its amidated derivate (Met-enk-NH(2)) with monolayers of the zwitterionic dimyristoylphosphatidylcholine (DMPC) and the negatively charged dimyristoylphosphatidylglycerol (DMPG) were studied. The surface tension (γ, mN/m) of DMPG and DMPC monolayers as a function of time (after injection of the peptide under the interface) was detected. The decrease in γ values showed that there was a strong penetration effect of both types of Met-enk molecules into the monolayers, being significantly stronger for the amidated derivate, Met-enk-NH(2). We suggest that the interaction between the neuropeptides and DMPC was predominantly determined by peptides amphiphilicity, while the electrostatic forces play significant role for the insertion of the cationic Met-enk-NH(2) in DMPG monolayers, especially at high packing densities. Our results demonstrate the potential of lipid monolayers formed in Langmuir&amp;amp;amp;#39;s trough to be successfully used as an elegant and simple membrane models to study lipid-peptide interactions at the air/water interface.
Acta Medica Bulgarica, 2010
Purpose: Alveolar surfactant (AS) components, including the specific surfactant proteins (SPs) SP... more Purpose: Alveolar surfactant (AS) components, including the specific surfactant proteins (SPs) SP-A, SP-B, SP-C, and SP-D, provides stability during the dynamic process of inhalation/exhalation. In prematurely born children different respiratory pathologies due to surfactant components deficiency, like Neonatal Respiratory Distress Syndrome, can be observed. Administration of corticosteroids to pregnant women at risk of preterm birth is an established intervention in clinical practice. In this study, we analyzed gastric aspirates (GAs), as alternative samples of tracheal aspirates and amniotic fluids for AS maturity determination. Samples were taken from prematurely born babies after antenatal corticosteroid therapy (CST) of pregnant women and were analyzed for the presence of specific surfactant proteins. Materials and Methods: Clinical samples of gastric aspirates were collected in the first minutes after delivery by using of a nasogastric tube and were analyzed by Sodium dodecyl ...
The aim of the present study was to estimate the physiology condition of lung surfactant by bioph... more The aim of the present study was to estimate the physiology condition of lung surfactant by biophysical analysis of different clinical samples in norm and pathology. The analyzed clinical samples included gastric aspirates (GA) from prematurely born and full term infants, tracheal aspirates (TA) from unventilated and ventilated lung during surgery in patients with nonsmall cells lung cancer (NSCLC) and broncho-alveolar lavage samples from a patient with pulmonary alveolar proteinosis, taken after each stage of the applied whole lung lavage procedure (WWL). By using the novel method of Axisymmetric Drop Shape Analysis, the equilibrium and dynamic surface characteristics (maximal and minimal surface tension during 10 cycles of compression-decompression) were determined. Our results showed that AS surface behavior differed in norm and pathology. The analyzed pathologies led to significant differences in the surface tension characteristics. The present study could find application into ...
PubMed, 2012
The aim of the present study was to estimate the lung surfactant maturity by analyses of gastral ... more The aim of the present study was to estimate the lung surfactant maturity by analyses of gastral aspirates (GA) from prematurely born and full-term infants. A biochemical analysis of the protein and lipid content in GA from the children groups tested was made. By thin-layer chromatography the individual phospholipids components in GA samples from prematurely born and full-term children were detected. In addition, by using the pending drop method the surface characteristics (equilibrium, maximal and minimal surface tension values) were determined. Our results showed an increase in the phospholipid and the protein concentrations in GA during pregnancy progress as well as significant differences in the individual phospholipids profile of the aspirates from prematurely born and full-term children. In case of surface characteristics a highest difference was observed for the minimal surface tension values (gammamin, m/Nm); while in the full-term children a lower surface tension was determined, in the prematurely born children significant higher values were reached, which define gammamin as the most informative from the parameters studied. Our results could find application into the clinical practice for fast surfactant maturity diagnostics in prematurely born children regarding lifesaving therapy with exogenous surfactants administration.
PubMed, May 24, 2013
Background: The optimal approach to detection of surfactant deficiency in the prematurely born in... more Background: The optimal approach to detection of surfactant deficiency in the prematurely born infants at birth remains unclear and the decision to apply exogenous surfactant is based mainly on the development of clinical and radiological signs of neonatal respiratory distress syndrome (NRDS). Objectives: We studied the biochemical and biophysical properties of gastric aspirates (GA) from prematurely born infants with NRDS and healthy full term infants with an aim to find an approachable method for assessment of surfactant maturity at birth. Material and methods: Forty-seven newborn infants divided into two groups were enrolled in the study. The first group comprised 34 healthy infants born at term (after 37 weeks of gestation). The second group included 13 premature infants (aged from 26 to 32 weeks of gestation) developing clinical signs of NRDS for which they were treated by assisted ventilation and exogenous surfactant. A biochemical analysis of the protein and lipid content of GA collected at birth was performed. The fatty acid composition of the GA samples was determined by Gas Chromatography-Mass Selective Detector (GS-MSD) analysis. The surface characteristics (equilibrium, maximal and minimal surface tension values) of the GA samples were measured by using the pending drop method. Data were compared between the groups by using Student's t test or Mann-Whitney analysis. Values were considered significantly different if the p value was = 0.05. Results: The mean phospholipids' concentration in GA of the premature infants was lower (295.7 µg / ml vs. 374.5 µg / ml) than in the term infants and the mean protein content was less in GA of the premature babies than the term newborns (574.5 µg / ml vs. 641.5 µg / ml). The measurement of dynamic surface characteristics of GA showed significantly higher mean values of the minimal surface tension (γmin) in the premature infants - 20.5 m / Nm compared to the term babies - 12.3 mN/m (p < 0,01). There was no difference between the equilibrium surface tensions (38 mN/m vs. 38 mN/m) of both groups; The mean values of maximal surface tension (?max) in GA did not differ significantly between the groups (50.1 mN/m vs. 48.5 mN/m). Conclusion: Our findings revealed lower phospholipids' and protein concentrations in the GA at birth from premature infants as compared to the healthy term infants. The dynamic surface characteristics of GA had significant differences between the two groups, the minimal surface tension being the most important parameter for evaluation of surfactant maturity. It could be used in the clinical practice for fast surfactant's assessment in the premature infants in regard to administration of exogenous surfactant.
The Journal of Membrane Biology, Dec 12, 2015
During the last decades opioid peptides, like enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are subject t... more During the last decades opioid peptides, like enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are subject to extensive studies due to their antinociceptive action in organism. According to the membrane catalysis theory, in order to adopt a proper conformation for binding to their receptors, opioid peptides interact with the lipid phase of the membrane receptor surrounding. With this regard, the aim of the present work was to study the effects of synthetic leucine-enkephalin and leucine-enkephalinamide on surface characteristics and morphology of lipid monolayers, composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, sphingomyelin, and cholesterol alone and with their mixtures. The lipids were chosen to represent a model of a membrane raft, since it is known that G-protein-coupled receptors, including opioid receptors, are located preferably in membrane rafts. By using Langmuir's monolayer method, the change in surface pressure of the model membranes before and after the addition of the synthetic enkephalins was studied, and the compressional moduli of the lipids and lipid-peptides monolayers were determined. In addition, by Brewster angle microscopy, the surface morphology of the lipid monolayers alone and after the injection of both enkephalins was monitored. Our results showed that both leucine-enkephalins affected the lipid monolayers surface characteristics, and led to an increase in surface density of the mixed surface lipids/ enkephalins films at loose lipid packing. This effect was more pronounced for the enkephalinamide, suggesting a different mechanism of interaction for the amidated enkephalin with the lipid phase, as compared to leucineenkephalin.
Enkephalins are pentapeptides (Tyr-Gly-Gly-Phe-Met/Leu) with proven antinociceptic action in orga... more Enkephalins are pentapeptides (Tyr-Gly-Gly-Phe-Met/Leu) with proven antinociceptic action in organism. They are neurotransmitters found in the central nervous system, which interact with opioid receptors in order to play their biological action. Enkephalin receptors belong to G-protein coupled receptors. It is known that these receptors are located in membrane rafts. Moreover, it is believed that in order to achieve conformation for binding to opioid receptors enkephalins interact with the lipid phase of the membranes. In the present work by using Langmuir's monolayer technique in combination with Wilhelmy's method for measuring the surface pressure, the interaction between synthetic enkephalins and monolayers composed of the raft lipids palmitoyl oleoyl phosphatidyl choline, sphingomyelin, cholesterol, as well as their double and triple mixtures was studied. From the pressure-area isotherm measured, the compressional modulus of the lipids and lipids-peptides monolayers was ...
Phospholipids in the composition of alveolar surfactant play a crucial role for its optimal funct... more Phospholipids in the composition of alveolar surfactant play a crucial role for its optimal functioning. Studies on fatty acid composition of individual phospholipid components of alveolar surfactant show that there is some correlation between the fatty acid profile and normal biophysical function of alveolar surfactant. So far the fatty acid profile has been determined in alveolar surfactant only. For the first time in the present study fatty acid analysis of lipids in gastric aspirates from children with Neonatal Respiratory Distress Syndrome (NRDS), premature infants and full-term babies was made. Qualitative and semi-quantitative analysis of fatty acids in gastric aspirate samples was made by Gas Chromatography-Mass Selective Detector. The results show that saturated/unsaturated fatty acids ratio is highest in the group of full-term infants. Moreover, the most common of all fatty acids is the saturated palmitic (C16: 0). Based on these and future studies we expect a new method b...
Acta Medica Bulgarica, 2010
European Respiratory Journal, 2014
Aim: To identify changes in the biochemical and biophysical behavior of lung surfactant (LS) in t... more Aim: To identify changes in the biochemical and biophysical behavior of lung surfactant (LS) in the unventilated and ventilated lung during surgery in patients with nonsmall cells lung cancer (NSCLC). The relationship between the surfactant changes and complications was examined. Material and Methods: In prospective study we included 32 patients (SG) with NSCLC and a control group(CG) of 29 patients without cancer. Surgery was performed under general anesthesia and a double lumen tube intubation. In both groups we performed bronchoalveolar lavage (BAL): A. From the operated (nonventilated) lung after intubation and before reventilation; B. From ventilated lung after intubation and at the end of anestesia. Biochemical analysis: the amount of phospholipids, cholesterol and proteins. Biophysical analysis: the equilibrium surface tension(γ eq ) and dynamic characteristics of monolayers (minimal surface tension γ min , maximal surface tension, γ max ). Results: In SG the amount of LS pho...
BANGYOZOVA, M., E. LONTOVA, A. TSANOVA, A. JORDANOVA, Y. YAMAKOVA, R. PETKOV and Z. LALCHEV, 2014... more BANGYOZOVA, M., E. LONTOVA, A. TSANOVA, A. JORDANOVA, Y. YAMAKOVA, R. PETKOV and Z. LALCHEV, 2014. In vitro analysis of broncho-alveolar lavage from a patient with pulmonary alveolar proteinosis. Bulg. J. Agric. Sci., Supplement 1: 18–23 Pulmonary alveolar proteinosis (PAP) is a heterogenous disorder of genetic or acquired etiologies characterized by intraalveolar accumulation of lipoproteinaceous material. The clinical course of the disease is variable, ranging from spontaneous remission to respiratory failure. The aim of the present study was to compare the biochemical and biophysical characteristics of broncho-alveolar lavage (BAL) from a patient with PAP, during the whole lung lavage (WLL) taken after each stage of the procedure. For this purpose biochemical and biophysical analysis of the clinical samples were made. The phospholipids (PLs) and the proteins concentrations of the samples were measured. For determination of protein content in broncho-alveolar lavage samples Lowry ...
Biological Markers in Fundamental and Clinical Medicine (collection of abstracts), 2019
SPECIFIC SURFACTANT PROTEINS AS CLINICAL MARKERS FOR LUNG MATURITY IN RISK NEWBORNS
The Journal of Membrane Biology, 2015
During the last decades opioid peptides, like enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are subject t... more During the last decades opioid peptides, like enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are subject to extensive studies due to their antinociceptive action in organism. According to the membrane catalysis theory, in order to adopt a proper conformation for binding to their receptors, opioid peptides interact with the lipid phase of the membrane receptor surrounding. With this regard, the aim of the present work was to study the effects of synthetic leucine-enkephalin and leucine-enkephalinamide on surface characteristics and morphology of lipid monolayers, composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, sphingomyelin, and cholesterol alone and with their mixtures. The lipids were chosen to represent a model of a membrane raft, since it is known that G-protein-coupled receptors, including opioid receptors, are located preferably in membrane rafts. By using Langmuir's monolayer method, the change in surface pressure of the model membranes before and after the addition of the synthetic enkephalins was studied, and the compressional moduli of the lipids and lipid-peptides monolayers were determined. In addition, by Brewster angle microscopy, the surface morphology of the lipid monolayers alone and after the injection of both enkephalins was monitored. Our results showed that both leucine-enkephalins affected the lipid monolayers surface characteristics, and led to an increase in surface density of the mixed surface lipids/ enkephalins films at loose lipid packing. This effect was more pronounced for the enkephalinamide, suggesting a different mechanism of interaction for the amidated enkephalin with the lipid phase, as compared to leucineenkephalin.
Akusherstvo i ginekologii͡a, 2012
The aim of the present study was to estimate the lung surfactant maturity by analyses of gastral ... more The aim of the present study was to estimate the lung surfactant maturity by analyses of gastral aspirates (GA) from prematurely born and full-term infants. A biochemical analysis of the protein and lipid content in GA from the children groups tested was made. By thin-layer chromatography the individual phospholipids components in GA samples from prematurely born and full-term children were detected. In addition, by using the pending drop method the surface characteristics (equilibrium, maximal and minimal surface tension values) were determined. Our results showed an increase in the phospholipid and the protein concentrations in GA during pregnancy progress as well as significant differences in the individual phospholipids profile of the aspirates from prematurely born and full-term children. In case of surface characteristics a highest difference was observed for the minimal surface tension values (gammamin, m/Nm); while in the full-term children a lower surface tension was determ...
Biotechnology & Biotechnological Equipment, 2009
Using Langmuir's monolayer technique, surface behaviour and the interaction between a synthetic a... more Using Langmuir's monolayer technique, surface behaviour and the interaction between a synthetic analogue of endogenous neuropeptide Methionine-enkephalin (Met-enk) and zwitterionic dimyristoylphosphatidylcholine (DMPC), and the negatively charged dimyristoylphosphatidylglycerol (DMPG) at air/water interface are studied. By using the Wilhelmy method, surface tension (γ, mN/m) changes (after injection of the peptide under the interface) of DMPG and DMPC monolayers as a function of time at given molecular area are detected. The decrease in γ values shows that there is a strong penetration effect of Metenk molecules into the monolayers. The comparison of the interaction between the hydrophobic pentapeptide and both phospholipid monolayers shows that the enkephalin interacts similarly with DMPG and DMPC molecules, and that the ability of Met-enk to penetrate correlates with the given surface area per lipid molecule. Based on the results obtained we suggest that in case of liquid-expanded monolayers the electrostatic attraction facilitates the interaction between the neuropeptide and the negatively charged phospholipids (DMPG), while at more compact ordering of lipid molecules the penetration of the enkephalin is preliminary due to hydrophobic interactions.
Amino Acids, 2013
Enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are opioid peptides with proven antinociceptive action in o... more Enkephalins (Tyr-Gly-Gly-Phe-Met/Leu) are opioid peptides with proven antinociceptive action in organism. They interact with opioid receptors belonging to G-protein coupled receptor superfamily. It is known that these receptors are located preferably in membrane rafts composed mainly of sphingomyelin (Sm), cholesterol (Cho), and phosphatidylcholine. In the present work, using Langmuir's monolayer technique in combination with Wilhelmy's method for measuring the surface pressure, the interaction of synthetic methionineenkephalin and its amidated derivative with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), Sm, and Cho, as well as with their double and triple mixtures, was studied. From the pressure/area isotherms measured, the compressional moduli of the lipids and lipid-peptide monolayers were determined. Our results showed that the addition of the synthetic enkephalins to the monolayers studied led to change in the lipid monolayers characteristics, which was more evident in enkephalinamide case. In addition, using Brewster angle microscopy (BAM), the surface morphology of the lipid monolayers, before and after the injection of both enkephalins, was determined. The BAM images showed an increase in surface density of the mixed surface lipids/enkephalins films, especially with double and triple component lipid mixtures. This effect was more pronounced for the enkephalinamide as well. These observations showed that there was an interaction between the peptides and the raft-forming lipids, which was stronger for the amidated peptide, suggesting a difference in folding of both enkephalins. Our research demonstrates the potential of lipid monolayers for elegant and simple membrane models to study lipid-peptide interactions at the plane of biomembranes.
Amino Acids, 2010
Using Langmuir&amp;amp;amp;#39;s monolayer technique, the surface behavior and the intera... more Using Langmuir&amp;amp;amp;#39;s monolayer technique, the surface behavior and the interaction of the synthetic neuropeptide methionine-enkephalin (Met-enk) and its amidated derivate (Met-enk-NH(2)) with monolayers of the zwitterionic dimyristoylphosphatidylcholine (DMPC) and the negatively charged dimyristoylphosphatidylglycerol (DMPG) were studied. The surface tension (γ, mN/m) of DMPG and DMPC monolayers as a function of time (after injection of the peptide under the interface) was detected. The decrease in γ values showed that there was a strong penetration effect of both types of Met-enk molecules into the monolayers, being significantly stronger for the amidated derivate, Met-enk-NH(2). We suggest that the interaction between the neuropeptides and DMPC was predominantly determined by peptides amphiphilicity, while the electrostatic forces play significant role for the insertion of the cationic Met-enk-NH(2) in DMPG monolayers, especially at high packing densities. Our results demonstrate the potential of lipid monolayers formed in Langmuir&amp;amp;amp;#39;s trough to be successfully used as an elegant and simple membrane models to study lipid-peptide interactions at the air/water interface.
Acta Medica Bulgarica, 2010
Purpose: Alveolar surfactant (AS) components, including the specific surfactant proteins (SPs) SP... more Purpose: Alveolar surfactant (AS) components, including the specific surfactant proteins (SPs) SP-A, SP-B, SP-C, and SP-D, provides stability during the dynamic process of inhalation/exhalation. In prematurely born children different respiratory pathologies due to surfactant components deficiency, like Neonatal Respiratory Distress Syndrome, can be observed. Administration of corticosteroids to pregnant women at risk of preterm birth is an established intervention in clinical practice. In this study, we analyzed gastric aspirates (GAs), as alternative samples of tracheal aspirates and amniotic fluids for AS maturity determination. Samples were taken from prematurely born babies after antenatal corticosteroid therapy (CST) of pregnant women and were analyzed for the presence of specific surfactant proteins. Materials and Methods: Clinical samples of gastric aspirates were collected in the first minutes after delivery by using of a nasogastric tube and were analyzed by Sodium dodecyl ...
The aim of the present study was to estimate the physiology condition of lung surfactant by bioph... more The aim of the present study was to estimate the physiology condition of lung surfactant by biophysical analysis of different clinical samples in norm and pathology. The analyzed clinical samples included gastric aspirates (GA) from prematurely born and full term infants, tracheal aspirates (TA) from unventilated and ventilated lung during surgery in patients with nonsmall cells lung cancer (NSCLC) and broncho-alveolar lavage samples from a patient with pulmonary alveolar proteinosis, taken after each stage of the applied whole lung lavage procedure (WWL). By using the novel method of Axisymmetric Drop Shape Analysis, the equilibrium and dynamic surface characteristics (maximal and minimal surface tension during 10 cycles of compression-decompression) were determined. Our results showed that AS surface behavior differed in norm and pathology. The analyzed pathologies led to significant differences in the surface tension characteristics. The present study could find application into ...