| 11. |
- Johansson, J, et al.
(författare)
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Pulmonary surfactant: emerging protein analogues
- 1999
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Ingår i: BioDrugs : clinical immunotherapeutics, biopharmaceuticals and gene therapy. - : Springer Science and Business Media LLC. - 1173-8804. ; 11:2, s. 71-77
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Tidskriftsartikel (refereegranskat)
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| 12. |
- JOHANSSON, J, et al.
(författare)
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Secondary structure and biophysical activity of synthetic analogues of the pulmonary surfactant polypeptide SP-C
- 1995
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Ingår i: The Biochemical journal. - : Portland Press Ltd.. - 0264-6021 .- 1470-8728. ; 307307 ( Pt 2), s. 535-541
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Tidskriftsartikel (refereegranskat)abstract
- Native pulmonary-surfactant-associated lipopolypeptide SP-C, its chemically depalmitoylated form and several synthetic analogues lacking the palmitoylcysteine residues were analysed for secondary structure in phospholipid micelles and for biophysical activity in 1,2-dipalmitoyl-sn-glycero-3- phosphocholine/phosphatidylglycerol/palmitic acid (68:22:9, by wt.). Compared with the native molecule, with the entire poly-valyl part in a known alpha-helical conformation, depalmitoylated SP-C was found to be still mainly alpha-helical, but with an approx. 20% decrease in the helical content. A synthetic hybrid polypeptide where the entire poly-valyl alpha-helical part of native SP-C had been replaced with the amino acid sequence of a transmembrane helix of bacteriorhodopsin is also predominantly alpha-helical. In contrast, synthetic SP-C analogues lacking only the palmitoyl groups, by replacement of the palmitoylcysteine residues with cysteine, phenylalanine or serine, or lacking the positively charged amino acids by replacement with alanine, are considerably less alpha-helical than both native and depalmitoylated SP-C. The data indicate that the SP-C palmitoyl groups are important for maintenance of the alpha-helical conformation in parts of the polypeptide, and that the poly-valyl alpha-helical conformation is not fully formed in synthetic SP-C polypeptides. Furthermore, the helical structure of both native and depalmitoylated SP-C in dodecylphosphocholine micelles is very resistant to thermal denaturation, exhibiting ordered structure at 90 degrees C. The alpha-helical content grossly parallels the peptide-induced acceleration of the spreading of phospholipids at an air/water interface and the increase of surface pressure. The data suggest that the alpha-helical conformation itself, rather than just the covalent structure, is of prime importance for the biological function of synthetic pulmonary-surfactant peptides.
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| 13. |
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| 14. |
- Johansson, J, et al.
(författare)
-
Synthetic surfactant protein analogues
- 1998
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Ingår i: Biology of the neonate. - : S. Karger AG. - 0006-3126. ; 7474 Suppl 1, s. 9-14
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Tidskriftsartikel (refereegranskat)abstract
- Surfactant preparations for the treatment of respiratory distress syndrome (RDS) that contain phospholipids and small amounts of the two hydrophobic proteins, SP-B and SP-C, are presently obtained from animal lungs. Since structural information about SP-B and SP-C is available, it appears possible to design analogues that can replace the native proteins in synthetic surfactants. SP-C contains a single helix, but analogues with the poly-Val sequence of the native molecule do not fold into a native-like α-helical conformation. However, replacement of all Val with Leu yields efficient folding into a helical structure and Leu-based SP-C analogues effectively accelerate spreading of surfactant lipids and exhibit some physiological activity in animal models of RDS. The inferior in vivo activity of synthetic surfactants containing SP-C only compared to that of surfactant preparations derived from natural sources may be caused by a lack of covalently linked palmitoyl groups in the analogues and/or absence of SP-B. SP-B is significantly larger than SP-C and has a tertiary fold of several amphipathic helices in a dimeric structure. A single simplified amphipathic helical peptide containing only Leu and Lys does not mimic the surface properties of SP-B in vitro. These circumstances make the design of SP-B analogues from solely structural considerations less likely to be successful than in the case of SP-C.
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| 15. |
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| 16. |
- Robertson, Agneta, 1954, et al.
(författare)
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Incidence of pulp necrosis subsequent to pulp canal obliteration from trauma of permanent incisors.
- 1996
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Ingår i: Journal of endodontics. - 0099-2399. ; 22:10, s. 557-60
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Tidskriftsartikel (refereegranskat)abstract
- Little long-term data are available on the frequency by which pulp canal obliteration (PCO) subsequent to trauma leads to pulp necrosis (PN). In this study, 82 concussed, subluxated, extruded, laterally luxated, and intruded permanent incisors presenting with PCO were followed for a period of 7 to 22 yr (mean 16 yr). At final clinical examination, 51% of the observed teeth responded normally to electric pulp testing (EPT). An additional 40% of the teeth although not responding to EPT were clinically and radiographically within normal limits. Yellow discoloration was a frequent finding. During the observation period, periapical bone lesions suggesting PN developed in seven teeth (8.5%). Twenty-yr pulp survival rate was 84%, as determined from life-table calculations. There was no higher frequency of PN in obliterated teeth subjected to caries, new trauma, orthodontic treatment, or complete crown coverage than intact teeth. Although the incidence of PN in teeth displaying PCO seems to increase over the course of time, prophylactic endodontic intervention on a routine basis does not seem justified.
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| 17. |
- Robertson, Agneta, 1954, et al.
(författare)
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Pulp calcifications in traumatized primary incisors. A morphological and inductive analysis study.
- 1997
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Ingår i: European journal of oral sciences. - 0909-8836. ; 105:3, s. 196-206
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate histopathological changes in primary teeth following trauma, and to look for possible correlations between the morphology of pulpal calcification and clinical findings. The material consisted of 123 primary teeth from 98 Danish children aged 9-108 months (mean age 33.5 +/- 19.7 months) at the time of injury. The specimens were analyzed by means of light and scanning and transmission electron microscopy. Data from the clinical investigation and from predetermined ranked parameters from the histological analysis were processed in a computerized inductive analysis program. The results, describing patterns of co-variation, are presented as a decision tree. The most common diagnosis was intrusion luxation (54%). In 41% of all teeth, the degree of obliteration was less than 1/4 of the pulpal lumen. In most cases (79%), no denticles were visible. When present, 80% of the denticles had a bone-like appearance. Tissues occluding the pulpal lumen were either dentin-like (49%), bone-like (19%), or fibrotic (9%). It could be concluded that these varying responses could not be correlated with explicit clinical diagnoses. However, in certain combinations, histological parameters could be correlated to clinical findings.
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| 18. |
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| 19. |
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