[The role of calcium ions and temperature on the effect of exogenous semisynthetic surfactants (experimental study)].
With the final aim of preventing neonatal respiratory distress syndrome (RDS), the present study was carried out on premature rabbits (28 days of gestation) that showed a moderate level of RDS. These animals were treated intratracheally with 25 microliters of semisynthetic surfactant, composed of natural adult rabbit surfactant/DPC/DPPG (1/0.6/0.6 mol P) in two types of carriers, saline solution (Sf) and a calcium solution (5 mM of Cl2Ca), which were also used as controls. This was maintained throughout the experimental period at 37 degrees C or 60 degrees C, while checking the effect of temperature on their behavior. The final results in the P/V curves showed a significant increase in the maximum distention in the cases treated with semisynthetic surfactant at 60 degrees C with calcium vehicle (60.96 ml/kg) and with saline solution as the vehicle (58.51 ml/kg) with respect to the control without treatment (44.08 ml/kg) (p < 0.05). In the morphometric quantification of the lungs fixed to 10 cm H2O, the highest distention (VV) is reached by the semisynthetic surfactant in calcium solution (Mez.Ca) at 37 degrees C (56.30%) and 60 degrees C (56.31%), followed by the semisynthetic surfactant in saline solution at 37 degrees C (55.17%). The maximum compliance expressed the highest distention (with or without emphysema) and the morphometric distention together with the compliance at 10 cm H2O showed the residual trapping and/or anticollapsing effect. The temperature and the type of vehicle used for the semisynthetic mixture did not significantly influence the lung distention.(ABSTRACT TRUNCATED AT 250 WORDS)
Padilla Sánchez
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MC
Departamento de Pediatría, Facultad de Medicina, Universidad de La Laguna, Tenerife.
Ferrer-Roca
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O
Doménech Martínez
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D000818:Animals; D002118:Calcium / Q000493:pharmacokinetics*; D004195:Disease Models, Animal; D004347:Drug Interactions; D005260:Female; D005333:Fetus / Q000187:drug effects; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007477:Ions; D011247:Pregnancy; D011663:Pulmonary Surfactants / Q000008:administration & dosage* / Q000494:pharmacology; D011817:Rabbits; D012127:Respiratory Distress Syndrome, Newborn / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D013696:Temperature
D007477:Ions; D011663:Pulmonary Surfactants; D002118:Calcium
Papel de los iones de calcio y la temperatura sobre la actuación de surfactantes semisintéticos exógenos (estudio experimental).