Discovery of 1,2,3-triazole-based fibroblast growth factor receptor modulators

To avoid production of a phospholipidosis-inducing metabolite, we replaced the amide structure of SUN13837 (1) with a 1,2,3-triazole. The resulting 1,2,3-triazole analog of 1 (compound 2) displayed greater neuroprotective activity than 1. Structural modification of 2 yielded compound 10, which showed improved neuroprotective activity and negligible mechanism-based inactivation against CYP3A4. In addition, installation of a methyl group at the 5-position of 1,2,3-triazole of 10 significantly boosted the neuroprotective activity. These 1,2,3-triazole derivatives displayed reduced phospholipidosis risk, sufficient systemic exposure, and high central nervous system penetration, and therefore may be potentially useful agents for the treatment of neurodegenerative diseases.     

Kinetic studies on Ce(IV)-induced hydrolysis of single-stranded and double-stranded oligonucleotides

The Ce(IV)-induced hydrolyses of DNA are kinetically investigated. The formation constants of the Ce(IV)-DNA complexes are in the following order: the single-stranded DNA > the double-stranded DNA > the dinucleotide. On the other hand, the catalytic rate constants for the single-stranded DNA and the double-stranded DNA are comparable with each other, but both of them are much smaller than the value for the dinucleotide hydrolysis.     

Microbial contribution to deposition of upper carboniferous and lower Permian seamount-top carbonates,Akiyoshi, Japan

Summary Microbial organisms significantly contributed to the accumulation of shallow-marine carbonates in an open-ocean realm of the Panthalassan Ocean during Late Carboniferous-Early Permian time. The Jigokudai plateau in the northern part of the Akiyoshidai Plateau is the study area, where the limestone of the Upper Carboniferous Kasimovian Stage to the Lower Permian Artinskian Stage is well exposed. The fusulinid biostratigraphy as well as top-bottom geopetal fabrics revealed that the rocks of the study area are overturned. The thickness of this succession is approximated to 150 m. The succession is lithologically divided into the Lower Jigokudai and Upper Jigokudai formations. The lime-stones of these formations were deposited in a lagoonal setting. The Lower Jigokudai formation (95 m thick: Kasimovian to Asselian) is characterized by sand shoal facies represented by crinoid-Tubiphytes-fusulinid peloidal pack/grainstones and oolitic grainstones. Phylloid algal grain/packstones and microbial boundstones subordinately crop out. The Upper Jigokudai Formation (55 m thick: Sakmarian to Artinskian) is characterized by shoal and tidal flat facies represented by mollusk-fusulinid peloidal grain/rudstones, and peloidal grain/rudstones and peloidal lime-mudstones, respectively. Laterally discontinuous microbial bound-stones occur intercalated in mollusk-fusulinid peloidal grain/rudstones. This formation contains pendant and meniscus cements, and flat-pebble breccia indicative of an intertidal deposition and subaerial exposure. Various types of boundstone and organosedimentary structures constructed mainly by filamentous cyanobacteria,Tubiphytes obscurus tubular microproblematicum A, and other microproblematica were recognized. Significant facies types are (1) filamentous cyanobacteria-microproblematicum A bind/framestones, (2)Tubiphytes obscurus bindstones, (3) stromatolitic bindstones, (4) microbial laminites, (5) microbially linked structures, (6) oncoids, (7) microproblematica B-C framestones. The calcimicrobes, combined with synsedimentary cementation, formed small-scale and low-relief mounds of these facies, and greatly contributed to the deposition of the Kasimovian to Artinskian Panthalassan buildup.     

Levosimendan improves LV systolic and diastolic performance at rest and during exercise after heart failure

The new myofilament Ca2+ sensitizer levosimendan (LSM) is a positive inotropic and vasodilatory agent. Its beneficial effects have been demonstrated at rest in congestive heart failure (CHF). However, its effect during exercise (Ex) in CHF is unknown. We assessed the effects of LSM on left ventricular (LV) dynamics at rest and during Ex in eight conscious, instrumented dogs with pacing-induced CHF. After CHF, with dogs at rest, LSM decreased arterial elastance (Ea) and increased LV contractile performance as assessed by the slope of LV pressure-volume (P-V) relation. LSM caused a >60% increase in the peak rate of mitral flow (dV/dtmax) due to decreases in minimal LV pressure and the time constant of LV relaxation (tau). LV arterial coupling, quantified as the ratio of end-systolic elastance (Ees) to Ea, was increased from 0.47 to 0.85%. LV mechanical efficiency, determined as the ratio of stroke work to total P-V area, was improved from 0.54 +/- 0.09 to 0.61 +/- 0.07. These beneficial effects persisted during Ex after CHF. Compared with CHF Ex dogs, treatment with LSM prevented Ex-induced abnormal increases in mean left atrial pressure and end-diastolic pressure and decreased Ees/Ea. With LSM treatment during CHF Ex, the early diastolic portion of the LV P-V loop was shifted downward with decreased minimal LV pressure and tau values and a further augmented dV/dtmax. Ees/Ea improved, and mechanical efficiency further increased from 0.61 +/- 0.07 to 0.67 +/- 0.07, which was close to the value reached during normal Ex. After CHF, LSM produced arterial vasodilatation; improved LV relaxation and diastolic filling; increased contractility, LV arterial coupling, and mechanical efficiency; and normalized the response to Ex.     

Heterogeneous cardiac sympathetic innervation in heart failure after myocardial infarction of rats

We examined cardiac neuronal function and beta-receptor with a dual-tracer method of [(131)I]meta-iodobenzylguanidine (MIBG) and [(125)I]iodocyanopindolol (ICYP) in rat heart failure after myocardial infarction (MI). In rats with MI, left ventricular (LV) systolic function decreased, and LV dimension and right ventricular (RV) mass increased gradually. MIBG accumulations of the noninfarcted LV (remote region) and RV decreased by 15% at 1 wk compared with sham-operated rats, and these accumulations were restored by 71% and 56%, respectively, at 24 wk compared with age-matched sham rats despite sustained depletion of myocardial norepinephrine contents in these regions. ICYP accumulation of the remote region and of the RV did not decrease at any stages. Myocardial MIBG distribution was heterogeneous at 1 wk when it was lower in the peri-infarcted region than in the remote region, associated with reduced ICYP accumulation in the peri-infarcted region. The heterogeneous distribution of both isotopes disappeared at 12 wk. Thus cardiac sympathetic neuronal alteration was coupled with downregulation of beta-receptors in rat heart failure after MI. The abnormal adrenergic signaling occurred heterogeneously in terms of ventricular distribution and time course after MI.     

Design and synthesis of highly active Alzheimer's beta-secretase (BACE1) inhibitors, KMI-420 and KMI-429, with enhanced chemical stability

Recently, we reported potent and small-sized BACE1 inhibitors KMI-358 and KMI-370 in which the Glu residue is replaced by a beta-N-oxalyl-DAP (l-alpha,beta-diaminopropionyl) residue at the P(4) position. The beta-N-oxalyl-DAP group is important for enhancing BACE1 inhibitory activity, but these inhibitors isomerized to alpha-N-oxalyl-DAP derivatives in solvents. Hence, we used a tetrazole moiety as a bioisostere of the free carboxylic acid of the oxalyl group. KMI-420 and KMI-429, containing a tetrazole ring, showed improved stability and potent enzyme inhibitory activity.     

Ultrastructural and immunohistochemical study of experimental atherosclerosis in Japanese quails

A marked plaque was produced at the tunica intima of the ascending aorta in all of the Japanese quails of 9 weeks old which fed on atherogenic diet containing 2% cholesterol for 8 weeks, while no structural changes of aortic wall were observed in Japanese quails which fed on normal basic food for the same period. The media of aorta in normal quails consist of smooth muscle cells, myofibroblast-like cells (MF) cells), and many successive elastic membranes. At the atherosclerotic lesion, many MF cells migrated from media into intima, and a part of smooth muscle cells were also differentiated to MF cells. Moreover, the most migrating MF cells differentiated to foam cells at the intimal thickness regions, and a few other MF cells also differentiated into endothelial cells of newly forming capillaries. By the immunohistochemical stainings, medial smooth muscle cells were negatively stained with anti-vimentin antibody, and the majority of cells in the intima (MF cells, foam cells, and endothelial cells) contained vimentin filaments. These results indicate that MF cells play a very important role in the development of atherosclerosis in Japanese quail. The morphologicals study offers some new insights into the evaluation of Japanese quails as an animal model of atherosclerosis.     

Functional stabilization of Kv1.5 protein by Hsp70 in mammalian cell lines

The aim of this study was to elucidate the mechanisms for regulations of cardiac Kv1.5 channel expression. We particularly focused on the role of heat shock proteins (Hsps). We tested the effects of Hsps on the stability of Kv1.5 channels using biochemical and electrophysiological techniques: co-expression of Kv1.5 and Hsp family proteins in mammalian cell lines, followed by Western blotting, immunoprecipitation, pulse-chase analysis, immunofluorescence and whole-cell patch clamp. Hsp70 and heat shock factor 1 increased the expression of Kv1.5 protein in HeLa and COS7 cells, whereas either Hsp40, 27 or 90 did not. Hsp70 prolonged the half-life of Kv1.5 protein. Hsp70 was co-immunoprecipitated and co-localized with Kv1.5-FLAG. Hsp70 significantly increased the immunoreactivity of Kv1.5 in the endoplasmic reticulum, Golgi apparatus and on the cell membrane. Hsp70 enhanced Kv1.5 current of transfected cells, which was abolished by pretreatment with brefeldin A or colchicine. Thus, Hsp70, but not other Hsps, stabilizes functional Kv1.5 protein.     

Mixed longitudinal study (6 years) of bone mineral density,muscle mass and muscle strength in the leg of aged females--relations to gravitational load and aging

Researchers examined the relationship between changes in physiological function in space and aging in older females. The hypotheses were that some of the changes may be due to a decrease in gravitational stimulation, but that some could be caused by aging itself. Data are based on a mixed longitudinal research study performed in aged females since 1995.     

The role of Schizosaccharomyces pombe DNA repair enzymes Apn1p and Uve1p in the base excision repair of apurinic/apyrimidinic sites

In Schizosaccharomyces pombe the repair of apurinic/apyrimidinic (AP) sites is mainly initiated by AP lyase activity of DNA glycosylase Nth1p. In contrast, the major AP endonuclease Apn2p functions by removing 3'-alpha,beta-unsaturated aldehyde ends induced by Nth1p, rather than by incising the AP sites. S. pombe possesses other minor AP endonuclease activities derived from Apn1p and Uve1p. In this study, we investigated the function of these two enzymes in base excision repair (BER) for methyl methanesulfonate (MMS) damage using the nth1 and apn2 mutants. Deletion of apn1 or uve1 from nth1Delta cells did not affect sensitivity to MMS. Exogenous expression of Apn1p failed to suppress the MMS sensitivity of nth1Delta cells. Although Apn1p and Uve1p incised the oligonucleotide containing an AP site analogue, these enzymes could not initiate repair of the AP sites in vivo. Despite this, expression of Apn1p partially restored the MMS sensitivity of apn2Delta cells, indicating that the enzyme functions as a 3'-phosphodiesterase to remove 3'-blocked ends. Localization of Apn1p in the nucleus and cytoplasm hints at an additional function of the enzyme other than nuclear DNA repair. Heterologous expression of Saccharomyces cerevisiae homologue of Apn1p completely restored the MMS resistance of the nth1Delta and apn2Delta cells. This result confirms a difference in the major pathway for processing the AP site between S. pombe and S. cerevisiae cells.