Pulmonary hypertension after liver transplantation in patients with antecedent hepatopulmonary syndrome: a report of 2 cases and review of the literature.

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PPHTN) are distinct clinical entities that may complicate liver disease. Although HPS and PPHTN are different, several reports describe 6 patients in whom both conditions have occurred, either concurrently or sequentially, sometimes with the onset of PPHTN after liver transplantation. The current report extends this sparse experience by reporting 2 patients who underwent liver transplantation for HPS and who developed pulmonary hypertension after liver transplantation. This experience calls for better understanding of the pathogenesis of HPS and PPHTN and ways to better predict their occurrence.     

The role of alpha-adrenoceptors in the amnestic effect of intracerebroventricular dexamethasone.

Corticosteroids exert dual enhancing or impairing effects on cognitive functions. While their memory-enhancing effects have been well investigated, the mechanisms involved in their amnestic effects are not completely understood. Thus, we examined the role of alpha-adrenoceptors on dexamethasone-induced amnesia using step-through passive avoidance test in rat. Intracerebroventricular (i.c.v.) injection of dexamethasone (5 and 10 microg per rat) decreased the retention latencies. Likewise, intraperitoneal administration of alpha(2)-adrenoceptor agonist clonidine (0.1-0.3 mg kg(-1)) but not alpha(2)-adrenoceptor antagonist yohimbine (0.5-2 mg kg(-1)) decreased the retention latency. Yohimbine pre-treatment decreased the amnestic effects of dexamethasone or dexamethasone plus clonidine. On the other hand, intraperitoneal administration of alpha(1)-adrenoceptor agonist phenylephrine (0.5-2 mg kg(-1)) per se increased, while prazosin at 2 mg kg(-1) decreased the retention latency. Administration of phenylephrine before dexamethasone completely reversed the amnestic effect of the latter, while prozosin did not affect dexamethasone-induced amnesia. These data suggest that dexamethasone may induce its amnestic effect through activation of alpha(2)-adrenoceptors, leading to decreased alpha(1)-adrenergic activity.     

Normal values of aortic root measurements in neonates

Summary Aortic root diameter measurements were obtained during the first week of life by M-mode echocardiography using leading edge methodology during early diastole in 172 preterm and 228 term neonates. At least 40 newborns were included in each 500-g birth-weight subgroup from 750 to 4750 g. The aortic root diameter increased linearly from 0.63±0.04 cm in newborns with birth weights of 750–1249 g to 1.06±0.06 cm in newborns of 4250–4750 g.F.J.W. was the recipient of a Fulbright research scholarship.