Neuro-inflammatory effects of photodegradative products of bilirubin.

Phototherapy was introduced in the early 1950's, and is the primary treatment of severe neonatal jaundice or Crigler-Najjar syndrome. Nevertheless, the potential biological effects of the products generated from the photodegradation of bilirubin during phototherapy remain unknown. This is very relevant in light of recent clinical observations demonstrating that the use of aggressive phototherapy can increase morbidity or even mortality, in extremely low birthweight (ELBW) infants. The aim of our study was to investigate the effects of bilirubin, lumirubin (LR, its major photo-oxidative product), and BOX A and B (its monopyrrolic oxidative products) on the central nervous system (CNS) using in vitro and ex vivo experimental models. The effects of bilirubin photoproducts on cell viability and expression of selected genes were tested in human fibroblasts, three human CNS cell lines (neuroblastoma SH-SY5Y, microglial HMC3, and glioblastoma U-87 cell lines), and organotypic rat hippocampal slices. Neither bilirubin nor its photo-oxidative products affected cell viability in any of our models. In contrast, LR in biologically-relevant concentrations (25 µM) significantly increased gene expression of several pro-inflammatory genes as well as production of TNF-α in organotypic rat hippocampal slices. These findings might underlie the adverse outcomes observed in ELBW infants undergoing aggressive phototherapy.

Bernard-Soulier syndrome: diagnosis by an ELISA method using monoclonal antibodies in 2 new unrelated patients.

Two unrelated patients with Bernard-Soulier syndrome and their relatives were studied. The patients demonstrated severe bleeding diathesis, the relatives were asymptomatic. The propositi showed the characteristic abnormalities of the syndrome: thrombocytopenia, a percentage of giant platelets higher than 65%, prolonged bleeding time and defective platelet aggregation to ristocetin and bovine plasma. On the contrary, in the heterozygotes, the typical abnormalities were not fully evident. We introduce a simple ELISA method for the precise definition of both homozygous and heterozygous states for the syndrome by the quantitation of platelet glycoprotein (GP) Ib. Specific binding of monoclonal antibodies anti-platelet GPIb was performed both by direct binding of radioiodinated antibody and by ELISA. Comparable results were obtained. In fact, we demonstrated near absence of GPIb in the 2 propositi and about half the amount in the heterozygotes studied compared to normal platelets.