Replication process of the parvovirus H-1. VIII. Partial denaturation mapping and localization of the replication origin of H-1 replicative-form DNA with electron microscopy.

Partial denaturation mapping, restriction endonuclease digestion, and electron microscopy were used to determine which end of the linear duplex replicative-form (RF) DNA molecule contains the origin of RF replication for the parvovirus H-1. This origin was localized within approximately 300 base pairs of the arbitrarily designated right end of the RF DNA, in the EcoRI or HaeII-A fragment. Based on denaturation behavior in formamide, the right end was also found to have a relatively high guanine plus cytosine content, whereas the region adjacent to the left terminus of the RF DNA molecule was adenine plus thymine rich.     

Replacing the cyclohexene-linker of FR181157 leading to novel IP receptor agonists: orally active prostacyclin mimetics. Part 6

The synthesis and biological activity of novel derivatives of our previously reported IP receptor agonist FR181157 is described. SAR studies to replace the cyclohexene-linker of FR181157 led to the discovery of compound 1i (FR207845) as a potent non-prostanoid PGI2 mimetic with good oral bioavailability.     

Reversal of mouse hepatic failure using an implanted liver-assist device containing ES cell-derived hepatocytes

Severe acute liver failure, even when transient, must be treated by transplantation and lifelong immune suppression. Treatment could be improved by bioartificial liver (BAL) support, but this approach is hindered by a shortage of human hepatocytes. To generate an alternative source of cells for BAL support, we differentiated mouse embryonic stem (ES) cells into hepatocytes by coculture with a combination of human liver nonparenchymal cell lines and fibroblast growth factor-2, human activin-A and hepatocyte growth factor. Functional hepatocytes were isolated using albumin promoter-based cell sorting. ES cell-derived hepatocytes expressed liver-specific genes, secreted albumin and metabolized ammonia, lidocaine and diazepam. Treatment of 90% hepatectomized mice with a subcutaneously implanted BAL seeded with ES cell-derived hepatocytes or primary hepatocytes improved liver function and prolonged survival, whereas treatment with a BAL seeded with control cells did not. After functioning in the BAL, ES cell-derived hepatocytes developed characteristics nearly identical to those of primary hepatocytes.     

Leaf size zonation pattern of woody species along an altitudinal gradient on Mt. Pulog,Philippines

Leaf size zonation along an altitudinal gradient from 2000–2700 m a.s.l. on Mt. Pulog, Cordillera mountain range, Luzon Is., Philippines was examined using the Raunkiaer-Webb classification system. The entire altitudinal range studied was dominated by the small leaf size classes which possess thick, lustrous, pubescent leaves adapted to high evapotranspiration, cold temperature and other stressful conditions. Altitudinal leaf size zonation was identified as follows: (1) pure needle leaved zone from 2000–2300 m a.s.l., (2) mixed needle leaved/microphyllous zone from 2300–2400 m a.s.l., (3) microphyllous zone from 2400–2600 m a.s.l. and, (4) microphyllous/nanophyllous zone from 2600–2700 m a.s.l., coinciding with the altitudinal vegetation zonation. This pattern is different from that in other tropical mountains, which usually show a gradual shift from a mesophyllous zone in the lowland to a nanophyllous zone in the upper subalpine. Stressful conditions such as steep topography (1200–2300 m a.s.l.), cloud cover, decrease of temperature, strong winds (2600–2700 m a.s.l.) could have influenced the altitudinal leaf size zonation on Mt. Pulog. The complex phytogeographical position of Mt. Pulog as a transition region between the tropics and subtropics have also influenced leaf size zonation as in eastern Himalaya, southwestern China and Taiwan.     

Discovery of new diphenyloxazole derivatives containing a pyrrolidine ring: orally active prostacyclin mimetics. Part 2

Synthetic and biological evaluation of novel diphenyloxazole derivatives containing a pyrrolidine ring, as a prostacyclin mimetic without the PG skeleton, are described. Asymmetric reduction of a ketone using a chiral Ru complex and reductive amination by NaBH(4) produces four isomers of the tetrahydronaphthalene ring and the pyrrolidine ring with high stereoselectivity. FR193262 (4), (R,R)-diphenyloxazolyl pyrrolidine derivative, displays high potency and agonist efficacy at the IP receptor and has good bioavailability in rats and dogs.     

A new cell-permeable peptide allows successful allogeneic islet transplantation in mice

Calcineurin inhibitors such as cyclosporine A and FK506 have been used for transplant therapy and treatment of autoimmune diseases. However, the inhibition of calcineurin outside the immune system has a number of side effects, including hyperglycemia. In the search for safer drugs, we developed a cell-permeable inhibitor of NFAT (nuclear factor of activated T cells) using the polyarginine peptide delivery system. This peptide provided immunosuppression for fully mismatched islet allografts in mice. In addition, it did not affect insulin secretion, whereas FK506 caused a dose-dependent decrease in insulin secretion. Cell-permeable peptides can thus provide a new strategy for drug development and may eventually be useful clinically.     

A novel pyridazinone derivative as a nonprostanoid PGI2 agonist

A novel optically pure pyridazinone derivative was synthesized and identified as a nonprostanoid PGI₂ agonist. It inhibited ADP-induced aggregation of human platelets with an IC₅₀ value of 0.081 μM and has high oral bioavailability (56%) with a long half-life (4.3 h) in rats.     

Evidence of intragenic recombination in G1 rotavirus VP7 genes

The G1 rotavirus is the most widespread genotype causing acute gastroenteritis in children. In an attempt to investigate the occurrence of intragenic recombination, 131 complete coding region sequences of VP7 genes of the G1 rotaviruses in GenBank were examined. Three hitherto-unreported intragenic recombinant rotaviruses were identified. It was noteworthy that two different types (interlineage and intersublineage) of intragenic recombination in rotaviruses were also found. This is the first report to demonstrate the existence of intragenic recombinations between interlineage and intersublineage in G1 rotaviruses.