Dynamics of Model Membranes by NMR

Amphiphilic molecules can create various aggregates in water. Concern about exploring such structures has been unabated for several decades due to the wide range of possible applications of lipid aggregates, from food technology to the pharmaceutical industry. The form of self-assembled structures depends on many factors, such as the type of amphiphilic molecule, the concentration, the level of hydration, the temperature, and the pH. Liposomes and micelles are the most widely known types of closed structures. Liposomes are more often used in the fields of medicine and pharmacy because they consist of nontoxic compounds and their composition and size can be controlled. Nuclear magnetic resonance (NMR) is one of the methods, which is most commonly used to study liposome properties. It can be used to observe changes in the structure, dynamics, and phase transition of lipid membranes. The membrane properties are changed under the influence of external factors, such as temperature, pH, and the presence of ions or drugs. The chapter aims to introduce and discuss the possibilities of the most useful NMR methods, 31P and 1H, to study the liposome properties. It also aims to show how various changes in the structure or dynamics of lipid molecules are visible in the NMR spectra

Application of Nuclear Magnetic Resonance Spectroscopy (NMR) to Study the Properties of Liposomes

The liposomes are well‐known lipid aggregates. The lipid composition and size of the liposomes can be controlled. The method of preparation, lipid composition, temperature, and pH have an influence on the liposome size and bilayer structure. The physicochemical properties of liposomes allow them to various applications. Nuclear magnetic resonance (NMR) is one of the methods used to study liposome properties. The abilities of the method are the high sensitivity and high resolution. Moreover, it provides information about dynamics and structure of molecules. 1H and 31P NMR are most convenient methods to study liposomes, because liposomes are typically formed from phospholipids. Additionally, two‐dimensional NMR spectroscopy reveals information about the nature of intermolecular and intramolecular interactions (scalar and dipole‐dipole interactions) that makes easier to interpret the structure of molecules. The chapter aims to introduce the NMR phenomenon, interactions between spins in magnetic field, dynamics of molecules and physical parameters of NMR spectra, and the necessary information for analyzing and interpreting high‐resolution NMR spectra. It also aims to show how various changes in the bilayer structure or dynamics of lipid molecules are visible in the NMR spectra

Transcendent and Transcendental Time Perspective Inventory

The purpose of this paper is to propose a tool to examine the transcendent and transcendental time perspective (TTTP). The inspiration to develop the scale were Philip G. Zimbardo and John N. Boyd studies, as well as by Lars Tornstam’s gerotranscendence theory and own research. The analysis of life from death to eternity is an interesting, heterogeneous and difficult subject of study. The proposed TTTP inventory can be utilized to investigate the future that extends beyond the frames of a personal time perspective, beyond the individual’s death as well as beyond the recognized, standard ways of understanding oneself, other people and the world. The inventory refers to changes of quantitative and qualitative nature relating to what is going to happen. It is composed of two sub-scales: the transcendental future and the transcendent future. The paper outlines the psychometric values of the qualities of the inventory, its validity and accuracy based on such indicators as the discriminative of items, the Cronbach alpha index for each of the sub-inventories and the exploratory factor analysis. The study findings come from analyses conducted on a group of 211 elderly subjects (the average age of 65; 70% women, 30% men). A confirmatory factor analysis was also conducted on a group of 238 elderly subjects (the average age of 66; 69% women, 28% men, 3% no gender data available). Additionally, the paper presents data on the accuracy of the external scale. The data are interpreted in the light of the time perspective theory as well as the existing studies

Enhanced Motor Function by Training in Spinal Cord Contused Rats Following Radiation Therapy

Weight-bearing stepping, without supraspinal re-connectivity, can be attained by treadmill training in an animal whose spinal cord has been completely transected at the lower thoracic level. Repair of damaged tissue and of supraspinal connectivity/circuitry following spinal cord injury in rat can be achieved by specific cell elimination with radiation therapy of the lesion site delivered within a critical time window, 2-3 weeks postinjury. Here we examined the effects of training in the repaired spinal cord following clinical radiation therapy. Studies were performed in a severe rat spinal cord contusion injury model, one similar to fracture/crush injuries in humans; the injury was at the lower thoracic level and the training was a combined hindlimb standing and stepping protocol. Radiotherapy, in a similar manner to that reported previously, resulted in a significant level of tissue repair/preservation at the lesion site. Training in the irradiated group, as determined by limb kinematics tests, resulted in functional improvements that were significant for standing and stepping capacity, and yielded a significant direct correlation between standing and stepping performance. In contrast, the training in the unirradiated group resulted in no apparent beneficial effects, and yielded an inverse correlation between standing and stepping performance, e.g., subject with good standing showed poor stepping capacity. Further, without any training, a differential functional change was observed in the irradiated group; standing capacity was significantly inhibited while stepping showed a slight trend of improvement compared with the unirradiated group. These data suggest that following repair by radiation therapy the spinal circuitries which control posture and locomotor were modified, and that the beneficial functional modulation of these circuitries is use dependent. Further, for restoring beneficial motor function following radiotherapy, training seems to be crucial

Interactions of sialic acid with phosphatidylcholine liposomes studied by 2D NMR spectroscopy

Biological membranes are complex systems which have attracted scientific interest for a long time and for various reasons. The sialic acid-liposome interactions at the molecular level depend on their hydro-lipophilic characteristics. The aim of the present study was to investigate the changes of conformation of the phospholipid (1,2-Diacyl-sn-glycero-3-phosphocholine) and sialic acid (2,8-(N-acetylneuraminic acid)) molecules and the type of interactions induced by the sialic acid molecules on membrane-like systems (liposomes) by 2D NMR (TOCSY, HETCOR, ROESY). The nature of the interaction of sialic acid with the model membrane depends on the structure of the phospholipid headgroups and the hydration of membrane. In ROESY spectra was observed the absence of dipole-dipole couplings within the choline head, between headgroups and glycerol, and between glycerol and fatty acid chains. It indicates an increase of the membrane dynamics in the presence of sialic acid. Moreover, the conformation of sialic acid molecule is changed in the presence of liposomes, which depends on stereochemistry of the chemical groups of the carbon atoms C7 and C8, and oxygen O8. The observed differences between the ROESY spectra of free and liposome bound sialic acid may be a consequence of a changed orientation of the pyranose ring from trans to gauche in the presence of liposomes. The sialic acid penetrate into the phospholipid bilayer to a sufficient depth to allow the dipole interaction. The present result that the correlation signal was found only between the methyl protons from the acetyl group of sialic acid and the methylene tail of phospholipid molecule in the ROESY spectrum indicates that the opposite end of the sialic acid molecule stays in the aqueous phase without interacting with membrane molecules

The future in the lives of older people

Wstęp. Artykuł prezentuje badania przyszłościowej perspektywy czasowej (PCC) ludzi w okresie późnej dorosłości. Celem badań była analiza rozpiętości i zawartości PCC z jej transcendentnym rozszerzeniem, czyli okresem obejmującym czas po śmierci u osób po 65. roku życia w kontekście wieku, wykształcenia oraz subiektywnej oceny stanu własnego zdrowia, sytuacji materialnej oraz dotychczasowej realizacji planów.Materiał i metody. W badaniach uczestniczyło 351 osób, w tym 119 mężczyzn i 232 kobiety w wieku 65 lat i powyżej. Do badań wykorzystano: ankietę do mierzenia PCC, kwestionariusz przyszłościowej perspektywy czasowej W. Lensa, skalę uogólnionych nastawień do przyszłości.Wyniki. Analiza zebranych danych pozwoliła na stwierdzenie, że u osób starych skraca się PCC. Osoby młodsze, lepiej wykształcone, oceniające pozytywnie realizację planów z przeszłości, a także własne zdrowie i finanse mają dłuższą PPC i więcej planów realizacji celów długich. Cele bliskie osób starych związane są z rodziną, zdrowiem i aspektem socjalno-bytowym, a cele długie — oprócz zdrowia i rodziny — dotyczą realizacji wartości ogólnych, takich jak: szczęście, dobro, uczciwość, oraz kwestii materialnych. Im starsi są ludzie, tym częściej myślą o śmierci. Połowa badanych tworzy plany na czas po śmierci, myśli na przykład o spotkaniu z bliskimi czy zbawieniu. Nastawienia do przyszłości u ludzi starych ulegają zmianie, im starsi są ludzie, tym więcej prezentują nastawień transcendentnych, a mniej realistycznych.Wnioski. Kształt PCC w starości zależy od wielu wewnętrznych i zewnętrznych czynników tworzących kontekst życia. Uzyskane wyniki pozwalają spojrzeć na PCC w sposób bardziej otwarty, uwzględniający obszar transcendentny, co daje nowe możliwości pracy z ludźmi starszymi nad ich przyszłością.Background. The article presents the research on the future time perspective of people in late adulthood. The aim of this study was to analyze the range and content of future time perspective with its transcendental extension, i.e. the period covering the time after death, in people over 65 years of age in the context of age, education and subjective assessment of their health status, financial situation and completion of the existing plans.Material and methods. The studies included 351 people, including 119 men and 232 women aged 65 yearsand above. The following methods were used in the research: questionnaire for measuring the future time perspective, W. Lens’s future time perspective questionnaire and the satisfaction with life scale.Results. Analysis of collected data allowed concluding that the future time perspective is reduced in older people. Younger persons, better educated, positively evaluating implementation of plans of the past, as well as their ownhealth and finances, have a longer future time perspective and more plans for achieving the long-term objectives. Short-term objectives of older people are associated with family, health and social aspects, while long-termobjectives relate, besides health and family, to implementation of the overall values such as happiness, goodness, fairness and substantive issues. The older people are, the more often they think about death. Half of therespondents make plans for time after death, e.g. meetings with the family, salvation. Attitudes to the future ofolder people are changing — they older people are, the more transcendental are their attitudes and less realistic.Conclusions. The shape of the future time perspective in old age depends on many internal and external factors that create the context of life. The obtained results allow looking at the future time perspective in a more open manner, taking into account the area of the transcendental. Through this they offer new opportunities of work with elderly people on their future