| 1. |
|
|
| 2. |
- Stichtenoth, G, et al.
(författare)
-
Comparison of Polymyxin E and Polymyxin B as an Additive to Pulmonary Surfactant in Escherichia coli Pneumonia of Ventilated Neonatal Rabbits
- 2017
-
Ingår i: Biomedicine hub. - : S. Karger AG. - 2296-6870. ; 2:2, s. 1-9
-
Tidskriftsartikel (refereegranskat)abstract
- <b><i>Background:</i></b> Ascending maternofetal bacterial infections often result in premature birth and neonatal respiratory distress. These neonates are treated with exogenous pulmonary surfactant (SF) and systemic antibiotics. Polymyxins are antimicrobiotic peptides that may bind to SF phospholipids. <b><i>Objectives:</i></b> Does topical administration of SF/polymyxin reduce bacterial growth in neonatal rabbit pneumonia and improve pulmonary function? <b><i>Methods:</i></b> Neonatal rabbits were tracheotomized and treated intratracheally with mixtures of porcine SF, SF/polymyxin E (PxE), or polymyxin B (PxB). Control animals received saline. Animals were then inoculated with <i>Escherichia coli</i> and ventilated for 4 h. During the experiment, peak insufflation pressures, dynamic lung compliance, and ECG were recorded. Pulmonary and renal bacterial load were determined. Lung histology was performed. Lung and kidney IL-8 were measured in subgroups. <b><i>Results:</i></b> Eighty-five animals were included in 2 experimental series, of which 78% survived 4 h of ventilation. <i>E. coli</i> inoculation caused severe neonatal pneumonia with median IL-8 levels of 2.2 ng/g in the lungs compared to a median of 0.2 ng/g in the lungs of the saline controls (<i>p</i> < 0.01). Lung compliance after 4 h was significantly increased at a mean of 0.48 ml/(kg·cm H<sub>2</sub>O) in the SF group and 0.43 in the SF + PxE group compared to 0.35 in the <i>E. coli</i> group (<i>p</i> < 0.01). In direct comparison, bacterial growth found in the <i>E. coli</i> group was reduced 20-fold in the SF + PxB group compared to 75-fold in the SF + PxE group. <b><i>Conclusion:</i></b> Addition of polymyxin to SF effectively promotes antimicrobial treatment and improves lung function in neonatal pneumonia of rabbits.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Almlen, A, et al.
(författare)
-
Concentration dependence of a poly-leucine surfactant protein C analogue on in vitro and in vivo surfactant activity
- 2007
-
Ingår i: Neonatology. - : S. Karger AG. - 1661-7819 .- 1661-7800. ; 92:3, s. 194-200
-
Tidskriftsartikel (refereegranskat)abstract
- <i>Background:</i> Modified natural surfactants currently used for treatment of respiratory distress syndrome contain about 0.5–1% (w/w phospholipids) of each of the surfactant proteins SP-B and SP-C. The supply of these preparations is limited and synthetic surfactant preparations containing lipids and peptides are under development. <i>Objectives:</i> To investigate the potential of different concentrations of the SP-C analogue SP-C33 in 1,2-dipalmitoyl-<i>sn</i>-glycero-3-phosphocholine/1-palmitoyl-2-oleoyl-<i>sn</i>-glycero-3-phosphoglycerol (68:31, w/w). <i>Methods:</i> Surface activity was evaluated in pulsating and captive bubble surfactometers and in immature newborn rabbits. <i>Results:</i> Preparations containing ≧1% SP-C33 achieve minimum surface tension <5 mN/m indicating good biophysical activity, and increase tidal volumes in premature rabbit fetuses to the same level as a modified natural surfactant preparation does. Alveolar patency at end expiration, as evaluated by measurement of lung gas volumes, histological assessment of alveolar expansion and determination of alveolar volume density, was lower in the animals treated with synthetic surfactant than in those receiving modified natural surfactant. <i>Conclusions:</i> These data suggest that SP-C33 is similarly efficient as the native peptide in improving surface properties of phospholipids mixtures and in increasing lung compliance in surfactant-deficient states, but that other components are needed to maintain alveolar stability at low airway pressures.
|
|
| 9. |
|
|
| 10. |
- Almlen, A, et al.
(författare)
-
Surfactant proteins B and C are both necessary for alveolar stability at end expiration in premature rabbits with respiratory distress syndrome
- 2008
-
Ingår i: Journal of applied physiology (Bethesda, Md. : 1985). - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 104:4, s. 1101-1108
-
Tidskriftsartikel (refereegranskat)abstract
- Modified natural surfactant preparations, used for treatment of respiratory distress syndrome in premature infants, contain phospholipids and the hydrophobic surfactant protein (SP)-B and SP-C. Herein, the individual and combined effects of SP-B and SP-C were evaluated in premature rabbit fetuses treated with airway instillation of surfactant and ventilated without positive end-expiratory pressure. Artificial surfactant preparations composed of synthetic phospholipids mixed with either 2% (wt/wt) of porcine SP-B, SP-C, or a synthetic poly-Leu analog of SP-C (SP-C33) did not stabilize the alveoli at the end of expiration, as measured by low lung gas volumes of ∼5 ml/kg after 30 min of ventilation. However, treatment with phospholipids containing both SP-B and SP-C/SP-C33 approximately doubled lung gas volumes. Doubling the SP-C33 content did not affect lung gas volumes. The tidal volumes were similar in all groups receiving surfactant. This shows that SP-B and SP-C exert different physiological effects, since both proteins are needed to establish alveolar stability at end expiration in this animal model of respiratory distress syndrome, and that an optimal synthetic surfactant probably requires the presence of mimics of both SP-B and SP-C.
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
|
|
