ABSTRACT
Raman spectra in the low-frequency spectral range-between 5 and 90cm^{-1}-were studied for multilamellar bilayers prepared with cholesterol (Chol) and phospholipids of three different types: doubly unsaturated lipids 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), monounsaturated lipids 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), and fully saturated lipids 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). The narrow peak seen below 250 K and positioned between 9 and 18cm^{-1}-depending on the system and temperature-was attributed to the vibrational eigenmode of a lipid monolayer. For the DOPC-Chol bilayer, the peak position and the peak width were found to monotonically increase and decrease, respectively, with the Chol concentration. For POPC-Chol and DMPC-Chol bilayers, these parameters revealed nonmonotonic concentration dependences, with an apparent minimum at the intermediate Chol content. The peak intensity was ascribed to interleaflet coupling. As in the literature, a coexistence of liquid-ordered and solid-ordered domains was suggested for the DMPC-Chol and POPC-Chol bilayers; the Chol concentration dependences of Raman peak parameters were discussed in line with this suggestion, under the assumption that the different composition of coexisting domains conserves upon cooling. We demonstrated that the obtained Raman data disagree with the suggested domain coexistence if the domain sizes are substantially larger than the lipid layer thickness.
Subject(s)
Cholesterol/chemistry , Lipid Bilayers/chemistry , Phospholipids/chemistry , Temperature , VibrationABSTRACT
UNLABELLED: Research objective was to compare Xenon and Sevoflurane anti stress activities during elective anaesthesia in Pediatric patients. MATERIAL AND METHODS: The results of anaesthesia in 42 patients in age from 1 to 18 years were analyzed. The clinical sings, BIS-index, Somatotropinum hormone and Cortisol levels in patient's blood were studied. RESULTS: Xenon and Sevoflurane provide sufficient level of sedation, analgesia and do not cause Somatotropinum hormone and Cortisol levels increase. CONCLUSION: Xenon and Sevoflurane have the same high anti stress activity However Xenon anaesthesia is characterized by more stable haemodynamics.
Subject(s)
Anesthetics, Inhalation/pharmacology , Methyl Ethers/pharmacology , Xenon/pharmacology , Adolescent , Anesthetics, Inhalation/administration & dosage , Child , Child, Preschool , Consciousness Monitors , Female , Growth Hormone/metabolism , Hemodynamics , Humans , Hydrocortisone/metabolism , Infant , Male , Methyl Ethers/administration & dosage , Sevoflurane , Xenon/administration & dosageSubject(s)
Benzopyrenes , DNA , Pyrenes , Thymus Gland , Animals , Binding Sites , Cattle , Epoxy Compounds , Mutagens , Nucleic Acid Conformation , Nucleic Acid Denaturation , Spectrometry, FluorescenceABSTRACT
Ultraviolet light-induced free radical alkylation with 2-propanol or D-ribose, initiated with di-tert-butyl peroxide, of poly (G), poly (U20G), and poly(A) led to the substitution of the appropriate group for the H-8 atom of the purines and addition across the 5,6-double bond of the pyrimidines. The alkylated polynucleotides were subjected to nucleolytic digestion with several nucleases. T1-RNase digestion of poly(G) irradiated with 2-propanol gave a mixture of the modified and non-modified mononucleotides. Similarly, pancreatic RNase digestion of the irradiated poly(U20G) resulted in a mixture of the appropriate mononucleotides. A T2-RNase treatment of poly(A) irradiated with 2-propanol gave the modified Ado-21:3'-P, while T2-RNase digestion of poly(A) irradiated with D-ribose led to the cyclic modified mononucleotides, in addition to the modified mononucleotides.
