Lead optimization of 5-amino-6-(2,2-dimethyl-5-oxo-4-phenylpiperazin-1-yl)-4-hydroxyhexanamides to reduce a cardiac safety issue: Discovery of DS-8108b,an orally active renin inhibitor

With the aim to address an undesired cardiac issue observed with our related compound in the recently disclosed novel series of renin inhibitors, further chemical modifications of this series were performed. Extensive structure–activity relationships studies as well as in vivo cardiac studies using the electrophysiology rat model led to the discovery of clinical candidate trans-adamantan-1-ol analogue 56 (DS-8108b) as a potent renin inhibitor with reduced potential cardiac risk. Oral administration of single doses of 3 and 10 mg/kg of 56 in cynomolgus monkeys pre-treated with furosemide led to significant reduction of mean arterial blood pressure for more than 12 h.     

The PMR Spectra of 1-Alkyl-2-carbo-azetidines: The Effect of the Nitrogen Lone Pair

Screening was carried out to obtain microorganisms which produced the enzyme to reduce the disulfide bond, from our type cultures of yeast. Among many strains of yeast showing activity to reduce the disulfide bond, Candida claussenii, Candida brumptii and Candida rugosa were selected to have the highest activity. The enzyme activity was detected in the cell free extracts, but not in culture broth.

The highest enzyme formation occured during the exponential growth phase, and rapid decrease of activity was observed in the stationary phase. Pantothenate and boron ion contributed to enzyme formation, and biotin and zinc ion to growth. The maximum enzyme activity was obtained in the following synthetic medium: 10% sucrose, 0.3% (NH₄)₂SO₄, 0.5% KH₂PO₄, 0.15% MgCl₂·6HO₂ 0.05% CaCl₂, 0.015% MnCl₂, 0.001% pantothenate, 0.0001% biotin, 0.0001% H₃BO₃, 0.00004% FeCl₃·6H₂O and 0.00008% ZnCl₂. In addition, 30°C of the cultural temperature and vigorous aeration showed good results for enzyme formation.     

Studies on Protein Metabolism in Higher Plants

A leaf protease of tobacco whose activity was enhanced during curing was purified about 60 times with ammonium sulfate fractionation, ethanol precipitation, calcium phosphate gel treatment and Sephadex G-200 column chromatography, and some properties of the protease were examined. The purified enzyme showed the optimum pH at 5.5 and the optimum temperature at 60°C. The protease activity was stable between pH 4.5 and 5.5 at 50°G or at pH 5.5 below 40°C for 1 hr, but completely destroyed at 70°C during 1 hr. The protease activity was greatly activated by reducing agents such as cysteine, glutathione or mercaptoethanol and inhibited by p-chloromercuribenzoate, phenyl- mercuric acetate or silver ions. Metal ions except for silver ion and ethylenediamine tetraacetic acid did not affect the protease activity so far examined.     

Impact of Robotic Assistance on Precision of Vitreoretinal Surgical Procedures

Purpose

To elucidate the merits of robotic application for vitreoretinal maneuver in comparison to conventional manual performance using an in-vitro eye model constructed for the present study.

Methods

Capability to accurately approach the target on the fundus, to stabilize the manipulator tip just above the fundus, and to perceive the contact of the manipulator tip with the fundus were tested. The accuracies were compared between the robotic and manual control, as well as between ophthalmologists and engineering students.

Results

In case of manual control, ophthalmologists were superior to engineering students in all the 3 test procedures. Robotic assistance significantly improved accuracy of all the test procedures performed by engineering students. For the ophthalmologists including a specialist of vitreoretinal surgery, robotic assistance enhanced the accuracy in the stabilization of manipulator tip (from 90.9 µm to 14.9 µm, P = 0.0006) and the perception of contact with the fundus (from 20.0 mN to 7.84 mN, P = 0.046), while robotic assistance did not improve pointing accuracy.

Conclusions

It was confirmed that telerobotic assistance has a potential to significantly improve precision in vitreoretinal procedures in both experienced and inexperienced hands.     

Cloning and characterization of ferredoxin and ferredoxin-NADP+ reductase from human malaria parasite

The human malaria parasite (Plasmodium falciparum) possesses a plastid-derived organelle called the apicoplast, which is believed to employ metabolisms crucial for the parasite's survival. We cloned and studied the biochemical properties of plant-type ferredoxin (Fd) and Fd-NADP+ reductase (FNR), a redox system that potentially supplies reducing power to Fd-dependent metabolic pathways in malaria parasite apicoplasts. The recombinant P. falciparum Fd and FNR proteins were produced by synthetic genes with altered codon usages preferred in Escherichia coli. The redox potential of the Fd was shown to be considerably more positive than those of leaf-type and root-type Fds from plants, which is favourable for a presumed direction of electron flow from catabolically generated NADPH to Fd in the apicoplast. The backbone structure of P. falciparum Fd, as solved by X-ray crystallography, closely resembles those of Fds from plants, and the surface-charge distribution shows several acidic regions in common with plant Fds and some basic regions unique to this Fd. P. falciparum FNR was able to transfer electrons selectively to P. falciparum Fd in a reconstituted system of NADPH-dependent cytochrome c reduction. These results indicate that an NADPH-FNR-Fd cascade is operative in the apicoplast of human malaria parasites.     

Lower peripheral circulation in eumenorrheic young women with premenstrual symptoms

Background  

This paper reports on the modification of the Parental Nurturance Scale (PNS), translation of the modified version (PNSM) from English to Japanese, and equivalence assessment between the PNSM and the translated version (PNSM-J). The PNS was modified so as to enable its use in nurturance studies where the prime source of nurturance might vary between respondents.     

Population genetic structure and demography of Magnolia kobus: variety borealis is not supported genetically

Species delimitations by morphological and by genetic markers are not always congruent. Magnolia kobus consists of two morphologically different varieties, kobus and borealis. The latter variety is characterized by larger leaves than the former. For the conservation of M. kobus genetic resources in natural forests, the relationships between morphological and genetic variation should be clarified. We investigated variations in nuclear microsatellites, chloroplast DNA (cpDNA) sequences and leaf morphological traits in 23 populations of M. kobus over the range of species. Two genetically divergent lineages, northern and southern were detected and their geographical boundary was estimated to be at 39°N. The northern lineage consisted of two genetic clusters and a single cpDNA haplotype, while the southern one had multiple genetic clusters and cpDNA haplotypes. The northern lineage showed significantly lower genetic diversity than the southern. Approximate Bayesian computation indicated that the northern and southern lineages had experienced, respectively, population expansion and long-term stable population size. The divergence time between the two lineages was estimated to be 565,000 years ago and no signature of migration between the two lineages after divergence was detected. Ecological niche modeling showed that the potential distribution area in northern Japan at the last glacial maximum was very small. It is thus considered that the two lineages have experienced different population histories over several glacial-inter-glacial cycles. Individuals of populations in the central to northern part of Honshu on the Sea of Japan side and in Hokkaido had large leaf width and area. These leaf characteristics corresponded with those of variety borealis. However, the delimitation of the northern and southern lineages detected by genetic markers (39°N) was not congruent with that detected by leaf morphologies (36°N). It is therefore suggested that variety borealis is not supported genetically and the northern and southern lineages should be considered separately when identifying conservation units based not on morphology but on genetic markers.