[Dealing with opioid dependence and withdrawal in hospitals]. / Omgaan met opioïdafhankelijkheid en -onthouding in het ziekenhuis.

BACKGROUND: In opioid addiction tolerance occurs requiring substitution with unusually high doses. A balance must be struck between the risk of overdose with respiratory depression and QTc interval prolongation on one hand and underdosing with withdrawal syndrome on the other hand. An unreliable anamnesis can complicate adequate dosing. CASE DESCRIPTION: A 30-year-old polydrug user with a severe dependence on methadone and heroin was admitted to the Intensive Care Unit after surgery for thoracic surgery. Upon cautious initiation with methadone, severe withdrawal and pain symptoms occurred. Doubling the dose made the withdrawal symptoms disappear without signs of overdose. CONCLUSION: During hospital admission of patients with high opioid tolerance the anamnestic equivalent high opioid dose can be started immediately, provided there is a possibility of monitoring the respiration and heart rhythm. The risk of withdrawal and insufficient pain relief in a hospital is generally greater than the risk of an overdose.

Outflow tract septation and the aortic arch system in reptiles: lessons for understanding the mammalian heart.

BACKGROUND: Cardiac outflow tract patterning and cell contribution are studied using an evo-devo approach to reveal insight into the development of aorto-pulmonary septation. RESULTS: We studied embryonic stages of reptile hearts (lizard, turtle and crocodile) and compared these to avian and mammalian development. Immunohistochemistry allowed us to indicate where the essential cell components in the outflow tract and aortic sac were deployed, more specifically endocardial, neural crest and second heart field cells. The neural crest-derived aorto-pulmonary septum separates the pulmonary trunk from both aortae in reptiles, presenting with a left visceral and a right systemic aorta arising from the unseptated ventricle. Second heart field-derived cells function as flow dividers between both aortae and between the two pulmonary arteries. In birds, the left visceral aorta disappears early in development, while the right systemic aorta persists. This leads to a fusion of the aorto-pulmonary septum and the aortic flow divider (second heart field population) forming an avian aorto-pulmonary septal complex. In mammals, there is also a second heart field-derived aortic flow divider, albeit at a more distal site, while the aorto-pulmonary septum separates the aortic trunk from the pulmonary trunk. As in birds there is fusion with second heart field-derived cells albeit from the pulmonary flow divider as the right 6th pharyngeal arch artery disappears, resulting in a mammalian aorto-pulmonary septal complex. In crocodiles, birds and mammals, the main septal and parietal endocardial cushions receive neural crest cells that are functional in fusion and myocardialization of the outflow tract septum. Longer-lasting septation in crocodiles demonstrates a heterochrony in development. In other reptiles with no indication of incursion of neural crest cells, there is either no myocardialized outflow tract septum (lizard) or it is vestigial (turtle). Crocodiles are unique in bearing a central shunt, the foramen of Panizza, between the roots of both aortae. Finally, the soft-shell turtle investigated here exhibits a spongy histology of the developing carotid arteries supposedly related to regulation of blood flow during pharyngeal excretion in this species. CONCLUSIONS: This is the first time that is shown that an interplay of second heart field-derived flow dividers with a neural crest-derived cell population is a variable but common, denominator across all species studied for vascular patterning and outflow tract septation. The observed differences in normal development of reptiles may have impact on the understanding of development of human congenital outflow tract malformations.