| 1. |
- Artlich, A, et al.
(författare)
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Single breath analysis of endogenous nitric oxide in the newborn
- 2001
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Ingår i: Biology of the neonate. - : S. Karger AG. - 0006-3126. ; 79:1, s. 21-26
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Tidskriftsartikel (refereegranskat)abstract
- Nitric oxide (NO) is found in the exhaled gas of humans immediately after birth. However, variations of endogenous NO concentration during the breathing cycle have not been studied in newborns. We examined 24 newborns without acute respiratory compromise during spontaneous nasal breathing. Gas was sampled from the tip of a thin nasal catheter placed in the hypopharynx. Endogenous NO concentrations measured by chemiluminescence were assigned to the breathing cycle using synchronized CO<sub>2</sub> recording. Exhaled NO could reproducibly be measured at 1.9 ± 0.2 parts per billion (ppb, mean ± SEM). Autoinhaled nasal NO peaks during regular breathing were 12.0 ± 1.7 ppb and reached intermittent maxima of 52.2 ± 5.8 ppb. During regular breathing 6 infants exhibited sudden decreases of nasal NO peaks to periods with <50% amplitude suggesting transient shortage of autoinhaled nasal NO. We conclude that tidal NO analysis can be used to assess upper and lower airway NO production noninvasively during spontaneous breathing in the newborn.
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| 2. |
- BLENNOW, M, et al.
(författare)
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Monoamine neurotransmitters and metabolites in the cerebrospinal fluid following perinatal asphyxia
- 1995
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Ingår i: Biology of the neonate. - : S. Karger AG. - 0006-3126. ; 67:6, s. 407-413
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Tidskriftsartikel (refereegranskat)abstract
- While the release of neurotransmitters is involved in the pathophysiology of brain damage following birth asphyxia, it also plays a role in endogenous defense against such damage. Levels of monoamines and the main cerebral monoamine metabolites in the cerebrospinal fluid (CSF) were measured in asphyxiated and control infants within 24 h after birth. The results indicate an increased turnover of noradrenaline (NA) and dopamine following asphyxia. Furthermore, the NA stores in the brain seem to be exhausted in some cases. We conclude that this increase in catecholamine turnover to some extent explains the clinical symptoms of hypoxic-ischemic encephalopathy and that it may reflect an intrinsic adaptive capacity to perinatal distress.
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| 3. |
- Calkovska, A, et al.
(författare)
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Biophysical and physiological properties of porcine surfactant enriched with polymyxin B
- 2005
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Ingår i: Biology of the neonate. - : S. Karger AG. - 0006-3126. ; 88:2, s. 101-108
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Tidskriftsartikel (refereegranskat)abstract
- <i>Objective:</i> We examined whether the biophysical and physiological properties of Curosurf<sup>®</sup> were improved by the cyclic amphipathic decapeptide polymyxin B (PxB). <i>Methods:</i> Curosurf was diluted to 1–5 mg/ml with PxB added at 1, 2 or 3% (w/w). Albumin was added at 40 mg/ml. Minimum surface tension (γ<sub>min</sub>) during surface compression was determined for each mixture with pulsating bubble. Immature newborn rabbits were treated with 2.5 ml/kg of Curosurf 80 mg/ml, or Curosurf 32 mg/ml with or without 2% PxB and ventilated for up to 5 h. <i>Results:</i> At surfactant concentration 2 mg/ml, γ<sub>min</sub> was high (17 ± 8.9 mN/m) but remained low (2.7 ± 0.8 mN/m) when PxB was added. Albumin inactivated Curosurf at both 2 and 3.5 mg/ml; this inactivation was prevented by 2% PxB. Treatment of newborn rabbits with Curosurf 80 mg/kg + 2% PxB significantly decreased incidence of pneumothorax in comparison with controls but had no significant effect on lung-thorax compliance or alveolar expansion. <i>Conclusion:</i> Addition of 2% PxB improves surface activity of Curosurf at low concentration, increases its resistance to inactivation by albumin, and reduces the incidence of pneumothorax in immature newborn rabbits undergoing prolonged ventilation.
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| 4. |
- Curstedt, T, et al.
(författare)
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New synthetic surfactant - how and when?
- 2006
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Ingår i: Biology of the neonate. - : S. Karger AG. - 0006-3126. ; 89:4, s. 336-339
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Tidskriftsartikel (refereegranskat)abstract
- Animal-derived surfactant preparations are very effective in the treatment of premature infants with respiratory distress syndrome but they are expensive to produce and supplies are limited. In order to widen the indications for surfactant treatment there is a need for synthetic preparations, which can be produced in large quantities and at a reasonable cost. However, development of clinically active synthetic surfactants has turned out to be more complicated than initially anticipated. The hydrophobic surfactant proteins, SP-B and SP-C, which are involved in the adsorption of surface-active lipids to the air-liquid interface of the alveoli and increase alveolar stability, are either too big to synthesize, structurally complex or unstable in pure form. A new generation of synthetic surfactants containing simplified phospholipid mixtures and small amounts of peptides replacing the hydrophobic proteins is currently under development and will in the near future be introduced into the market. However, more trials need to be performed before any conclusions can be drawn about the effectiveness of these synthetic surfactants in relation to natural animal-derived preparations.
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| 5. |
- Curstedt, T, et al.
(författare)
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New synthetic surfactants--basic science
- 2005
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Ingår i: Biology of the neonate. - : S. Karger AG. - 0006-3126. ; 87:4, s. 332-7
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Tidskriftsartikel (refereegranskat)abstract
- The hydrophobic surfactant proteins, SP-B and SP-C, promote adsorption of surface-active lipids to the air-liquid interface of the alveoli and are essential for alveolar stability and gas exchange. Synthetic surfactant preparations must contain at least one of these hydrophobic proteins, or analogs thereof, to have optimal effects when administered into the airways of patients with lung diseases. However, development of clinically active artificial surfactants has turned out to be more complicated than initially anticipated since the native hydrophobic proteins are structurally complex or unstable in pure form. The proteins have been replaced by different analogs which have the right conformation without forming oligomers. Increased understanding of the surfactant proteins will hopefully lead to development of effective synthetic surfactants which can be produced in large quantities for treatment of a wide range of respiratory disorders. Furthermore, the lipid composition seems to be important, as well as a high lipid concentration in the suspension. For successful treatment of many respiratory diseases, it is also desirable that the synthetic surfactant resists inactivation by plasma components leaking into the alveoli.
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| 10. |
- Huang, QW, et al.
(författare)
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Effects of inhaled nitric oxide and high-frequency ventilation in rabbits with meconium aspiration
- 1999
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Ingår i: Biology of the neonate. - : S. Karger AG. - 0006-3126. ; 76:6, s. 374-382
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To evaluate effects of inhaled nitric oxide (iNO) in experimental meconium aspiration treated with high-frequency (HFV) or conventional mechanical ventilation (CMV). Ventilated adult rabbits had meconium instilled intratracheally resulting in respiratory failure as evidenced by more than 50% reduction of dynamic lung compliance (Cdyn) and increase in mean oxygenation index (OI) from 1 to 16. The animals were then allocated to 2 groups treated without (control) or with iNO at 20 ppm (NO). In each group the animals were initially ventilated with CMV or HFV mode for 3 h and then in a crossover fashion with HFV or CMV for another 3 h (CMV→HFV, HFV→CMV), respectively. In the first 3 h of treatment, the animals subjected to HFV-CMV in the control, and those with both HFV-CMV and CMV-HFV in the NO group had significantly reduced OI. In the subsequent 3 h, the animals in the control group with CMV-HFV did not improve in OI and those with HFV-CMV had deteriorated. In the NO group with both CMV-HFV and HFV-CMV moderate improvement of OI was observed. Platelet aggregation capability and counts were significantly decreased and bleeding time prolonged in animals receiving iNO treatment. These results suggest that both HFV alone and a combined treatment of iNO with either CMV or HFV are more effective in improving blood oxygenation than that of CMV in this animal model. The influence of iNO on platelet aggregation should be considered.
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