Postextrasystolic contractile decay always contains exponential and alternans components in canine heart

In isolated, blood-perfused canine hearts, postextrasystolic potentiation (PESP) decays monotonically after a noncompensatory pause following a spontaneous extrasystole (ES). The monotonic PESP decay yields myocardial internal Ca(2+) recirculation fraction (RF). We have found that after a compensatory pause (CP), PESP decays in alternans, consisting of an exponential and a sinusoidal decay component. We have proposed that this exponential component also yields RF. In the present study, we examined the reliability of this alternative method by widely changing the ES coupling interval (ESI), CP, and heart rate in the canine excised, cross-circulated left ventricle. We found that all PESP decays consisted of the sum of an exponential and a sinusoidal decay component of variable magnitudes whether a CP existed or not. Their decay constants as well as the calculated RF were independent of the ESI and CP. This confirmed the utility of our alternative RF determination method regardless of the ESI, CP, and heart rate. Direct experimental evidence of Ca(2+) dynamics supportive of this alternative method, however, remains to be obtained.     

Characterization of the cells in the repair tissue of full-thickness articular cartilage defects

 It is well established that a full-thickness articular cartilage defect is repaired with a fibrocartilaginous tissue, cells of which are derived from undifferentiated mesenchymal stem cells in the bone marrow. To characterize the repair cells biochemically, full-thickness defects were created in rabbit knee joints and the repair tissues taken at 3, 6, and 12 weeks after surgery. The repair cells were cultured and examined biochemically to investigate the effects of four exogenous growth factors with regard to the metabolism of type II collagen and proteoglycans. A significant increase of carboxy-terminal type II procollagen peptide production was observed in the conditional medium of the repair cells, especially taken at 6 weeks after surgery, in the presence of each growth factor. Glycosaminoglycan content was also increased and proteoglycan synthesis stimulated. The repair cells taken at the early stage of the repair process could originally have more activity of type II collagen synthesis, and the growth factors used could enhance the differentiation of the repair cells in vitro. Accepted: 3 November 1997     

Combined Genetic and Genealogic Studies Uncover a Large BAP1 Cancer Syndrome Kindred Tracing Back Nine Generations to a Common Ancestor from the 1700s

We recently discovered an inherited cancer syndrome caused by BRCA1-Associated Protein 1 (BAP1) germline mutations, with high incidence of mesothelioma, uveal melanoma and other cancers and very high penetrance by age 55. To identify families with the BAP1 cancer syndrome, we screened patients with family histories of multiple mesotheliomas and melanomas and/or multiple cancers. We identified four families that shared an identical BAP1 mutation: they lived across the US and did not appear to be related. By combining family histories, molecular genetics, and genealogical approaches, we uncovered a BAP1 cancer syndrome kindred of ~80,000 descendants with a core of 106 individuals, whose members descend from a couple born in Germany in the early 1700s who immigrated to North America. Their descendants spread throughout the country with mutation carriers affected by multiple malignancies. Our data show that, once a proband is identified, extended analyses of these kindreds, using genomic and genealogical studies to identify the most recent common ancestor, allow investigators to uncover additional branches of the family that may carry BAP1 mutations. Using this knowledge, we have identified new branches of this family carrying BAP1 mutations. We have also implemented early-detection strategies that help identify cancers at early-stage, when they can be cured (melanomas) or are more susceptible to therapy (MM and other malignancies).     

Analytical Model for Estimating Terrestrial Cosmic Ray Fluxes Nearly Anytime and Anywhere in the World: Extension of PARMA/EXPACS

By extending our previously established model, here we present a new model called “PHITS-based Analytical Radiation Model in the Atmosphere (PARMA) version 3.0,” which can instantaneously estimate terrestrial cosmic ray fluxes of neutrons, protons, ions with charge up to 28 (Ni), muons, electrons, positrons, and photons nearly anytime and anywhere in the Earth’s atmosphere. The model comprises numerous analytical functions with parameters whose numerical values were fitted to reproduce the results of the extensive air shower (EAS) simulation performed by Particle and Heavy Ion Transport code System (PHITS). The accuracy of the EAS simulation was well verified using various experimental data, while that of PARMA3.0 was confirmed by the high R ² values of the fit. The models to be used for estimating radiation doses due to cosmic ray exposure, cosmic ray induced ionization rates, and count rates of neutron monitors were validated by investigating their capability to reproduce those quantities measured under various conditions. PARMA3.0 is available freely and is easy to use, as implemented in an open-access software program EXcel-based Program for Calculating Atmospheric Cosmic ray Spectrum (EXPACS). Because of these features, the new version of PARMA/EXPACS can be an important tool in various research fields such as geosciences, cosmic ray physics, and radiation research.     

Migration Stimulating Factor (MSF) promotes fibroblast migration by inhibiting AKT

The protein kinase AKT is activated strongly by many motogenic growth factors, yet has recently been shown capable of inhibiting migration in several cell types. Here we report that treatment with Migration Stimulating Factor (MSF), a truncated form of fibronectin that promotes the migration of many cell types, inhibits AKT activity in human fibroblasts and endothelial cells. In fibroblasts, treatment with either MSF or the AKT inhibitor, Akti-1/2, stimulated migration into 3D collagen gels to a similar extent and the effects of Akti-1/2 on migration could be blocked by the expression of an inhibitor-resistant mutant, AKT1 W80A. These data indicate that MSF promotes fibroblast migration, at least in part, by inhibiting the activity of AKT.     

Quantification of a potent mutagenic 4-amino-3,3'-dichloro-5,4'-dinitrobiphenyl (ADDB) and the related chemicals in water from the Waka River in Wakayama, Japan

4-Amino-3,3'-dichloro-5,4'-dinitrobiphenyl (ADDB) is a novel chemical exerting strong mutagenicity, especially in the absence of metabolic activation. In addition to mutagenicity, ADDB may also disrupt the endocrine system in vitro. ADDB may be discharged from chemical plants near the Waka River and could be unintentionally formed via post-emission modification of drainage water containing 3,3'-dichlorobenzidine (DCB), which is a precursor in the manufacture of polymers and dye intermediates in chemical plants. The main purpose of this study was to make a comprehensive survey of the behaviour and levels of ADDB and suspected starting material or intermediates of ADDB, i.e., DCB, 3,3'-dichloro-4,4'-dinitrobiphenyl (DDB), and 4-amino-3,3'-dichloro-4'-nitrobipheny (ADNB) in Waka River water samples. We also postulated the formation pathway of ADDB. Water samples were collected at five sampling sites from the Waka River four times between March 2003 and December 2004. Samples were passed through Supelpak2 columns, and adsorbed materials were then extracted with methanol. Extracts were used for quantification of ADDB and the related chemicals by HPLC on reverse-phase columns; mutagenicity was evaluated in the Salmonella assay using the O-acetyltransferase-overexpressing strain YG1024. High levels of ADDB, DCB, DDB, and ADNB (12.0, 20,400, 134.8, and 149.4ng/L-equivalent) were detected in the samples collected at the site where wastewater was discharged from chemical plants into the river. These water samples also showed stronger mutagenicity in YG1024 both with and without S9 mix than the other water samples collected from upstream and downstream sites. The results suggest that ADDB is unintentionally formed from DCB via ADNB in the process of wastewater treatment of drainage water containing DCB from chemical plants.     

Impaired NO-mediated vasodilation with increased superoxide but robust EDHF function in right ventricular arterial microvessels of pulmonary hypertensive rats

Pulmonary hypertension (PH) causes right ventricular (RV) hypertrophy and, according to the extent of pressure overload, eventual heart failure. We tested the hypothesis that the mechanical stress in PH-RV impairs the vasoreactivity of the RV coronary microvessels of different sizes with increased superoxide levels. Five-week-old male Sprague-Dawley rats were injected with monocrotaline (n=126) to induce PH or with saline as controls (n=114). After 3 wk, coronary arterioles (diameter = 30-100 microm) and small arteries (diameter = 100-200 microm) in the RV were visualized using intravital videomicroscopy. We evaluated ACh-induced vasodilation alone, in the presence of N(omega)-nitro-L-arginine methyl ester (L-NAME), in the presence of tetraethylammonium (TEA) or catalase with or without L-NAME, and in the presence of SOD. The degree of suppression in vasodilation by L-NAME and TEA was used as indexes of the contributions of endothelial nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF), respectively. In PH rats, ACh-induced vasodilation was significantly attenuated in both arterioles and small arteries, especially in arterioles. This decreased vasodilation was largely attributable to reduced NO-mediated vasoreactivity, whereas the EDHF-mediated vasodilation was relatively robust. The suppressive effect on arteriolar vasodilation by catalase was similar to TEA in both groups. Superoxide, as measured by lucigenin chemiluminescence, was significantly elevated in the RV tissues in PH. SOD significantly ameliorated the impairment of ACh-induced vasodilation in PH. Robust EDHF function will play a protective role in preserving coronary microvascular homeostasis in the event of NO dysfunction with increased superoxide levels.     

Involvement of p38alpha in kainate-induced seizure and neuronal cell damage

We investigated how p38alpha mitogen-activated protein kinase (p38) is related to kainate-induced epilepsy and neuronal damages, by using the mice with a single copy disruption of the p38 alpha gene (p38alpha(+/-)). Mortality rate and seizure score of p38alpha(+/-) mice administered with kainate were significantly reduced compared with the case of wild-type (WT) mice. This was clearly supported by the electroencephalography data in which kainate-induced seizure duration and frequency in the brain of p38alpha(+/-) mice were significantly suppressed compared to those of WT mice. As a consequence of seizure, kainate induced delayed neuronal damages in parallel with astrocytic growth in the hippocampus and ectopic innervation of the mossy fibers into the stratum oriens in the CA3 region of hippocampus in WT mice, whose changes were moderate in p38alpha(+/-) mice. Likewise, kainate-induced phosphorylation of calcium/calmodulin-dependent kinase II in the hippocampus of p38alpha (+/-) mice was significantly decreased compared to that of WT mice. These results suggest that p38alpha signaling pathway plays an important role in epileptic seizure and excitotoxicity.     

Quantification of ortholog losses in insects and vertebrates

Background  

The increasing number of sequenced insect and vertebrate genomes of variable divergence enables refined comparative analyses to quantify the major modes of animal genome evolution and allows tracing of gene genealogy (orthology) and pinpointing of gene extinctions (losses), which can reveal lineage-specific traits.