Mami Ohsugi

Transfer of 125I-albumin from blood to brain in newborn rats and the effect of hyperbilirubinemia on the transfer.

Transfer of albumin from blood into cerebellum and cerebrum was examined in postnatal rats. 125I-Albumin was injected into rats on day 3, 7, 14, 28 or 70. The ratio of albumin concentration in the cerebellum or in the cerebrum to that in the plasma 2 h after the injection, hereinafter termed the relative albumin level (RA), was calculated and used as a criterion for the albumin transfer. The RA in both the cerebellum and the cerebrum decreased with age, but plateaued between days 28 and 70. The level was significantly higher in the cerebellum than in the cerebrum on days 3 and 7. This was not observed, however, on days 28 and 70. Significant correlations were indicated between 125I-albumin levels in the plasma and those in the cerebellum or cerebrum on days 7 and 14, but not on day 28. No significant difference in the RA in the cerebellum and the cerebrum was detected between jaundiced homozygous Gunn rats and control nonjaundiced rats at all ages examined. These results demonstrated that albumin could enter the brain tissue from the blood at least until postnatal day 14 and that the endogenous bilirubin had no effect on the albumin transfer into the brain. The relationship between the immaturity of brain and the transfer of albumin into the brain was discussed.

Immunocytochemical detection of Ca2+-dependent subspecies of protein kinase C in mouse embryos before and during compaction

SummaryTo confirm the possibility that protein kinase C is involved in compaction of mouse embryos, the presence and distribution pattern of Ca2+-dependent subspecies of this enzyme in mouse embryos, before and during compaction, were examined immunocytochemically with three different monoclonal antibodies. These were MC-1a, MC-2a and MC-3a, which selectively interact with the subspecies of the enzyme known as types I, II and III, respectively. Only when embryos were incubated with MC-3a, was immunofluorescence clearly detected in all cells of embryos before and during compaction. This result demonstrates the presence of type III protein kinase C in embryos before and during compaction and suggests the possibility that the type III enzyme may be involved in compaction. No marked differences were found in the distribution pattern of the type III enzyme between embryos examined before and during compaction.

Transfer of bilirubin covalently bound to 125I-albumin from blood to brain in the gunn rat newborn

Transfer of bilirubin covalently bound to albumin (Alb.B) from blood into brain was examined in Gunn rats at postnatal day 3, 7, 14, 28 or 70. The ratio of the 125I-Alb.B concentration in the brain to that in the plasma 2 h after the injection (RAB) was used as a criterion for Alb.B transfer. RAB in brain decreased with age until day 28. Significant correlations were indicated between 125I-Alb.B plasma levels and those in the brain at days 7 and 14, but not at day 28. These results suggested that 125I-Alb.B could transfer from the blood to the brain until day 14. Comparison of the relative amount of radioactivity accumulated in the brain by a 125I-Alb.B injection with that of 125I-albumin alone revealed higher radioactivity in the former than the latter only at day 14, suggesting a transient appearance of particular cellular elements with high affinity to bilirubin in the developmental stage of the brain.

Stage‐Specific Relationship between Plasma Total and Cerebellar Bilirubin Levels during Early Postnatal Period in Jaundiced Gunn Rats

Abstract Relationships between plasma total or unbound bilirubin level and cerebellar bilirubin level were examined during the first 14 days after birth in homozygous Gunn rats with hyperbilirubinemia. Correlation coefficients between plasma total and cerebellar bilirubin levels were 0.63, 0.74, 0.48 and 0.60 at days 3, 7, 9 and 11, respectively, and were all significant, whereas the coefficient at day 14 (0.10) was not significant. The correlation coefficients between plasma unbound and cerebellar bilirubin levels were 0.40, 0.09, and 0.12 at days 7, 11 and 14, respectively, and were not significant. Thus, the cerebellar bilirubin level is suggested to depend on the plasma total bilirubin level from day 3 to 11.