Automatic sleep/wake scoring from body motion in bed: validation of a newly developed sensor placed under a mattress

The purpose of this study was to formulate a "sleep/wake" scoring algorithm for processing activity measurements obtained using a newly developed nonwear actigraphy (NWA) device, and to test its validity. The NWA device has a highly sensitive pressure sensor and is placed under a mattress. It can continuously record the activity of a person lying on the mattress and identify an "in-bed/out-of-bed" state from the vibrations of the mattress. We formulated the sleep/wake scoring algorithm by using data obtained simultaneously by wrist actigraphy (Act) and the NWA device in 33 healthy participants. Agreement rate, sensitivity, and specificity with Act were 95.7%, 97.6%, and 75.8% (33 healthy people); the corresponding values were 85.9%, 89.1%, and 79.8% for 12 nursing home residents and 93.7%, 97.2%, and 60.8% for 60 nights for 6 healthy persons who slept 10 nights on their futons. Agreement rate, sensitivity, and specificity with polysomnography were in almost perfect agreement with Act (12 nights; 6 healthy persons who slept 2 nights). All our validation results indicate that the NWA device, placed under a mattress or a futon, can produce almost identical sleep/wake scores to Act. It is expected that the NWA device, a nonwear device for scoring sleep/wake and in-bed/out-of-bed, enables convenient long-term sleep-related evaluation in various fields, including hospital settings, home-care settings, and care facility settings such as nursing homes.     

Visualization of conformational distribution of short to medium size segments in globular proteins and identification of local structural motifs

Analysis of the conformational distribution of polypeptide segments in a conformational space is the first step for understanding a principle of structural diversity of proteins. Here, we present a statistical analysis of protein local structures based on interatomic C(alpha) distances. Using principal component analysis (PCA) on the intrasegment C(alpha)-C(alpha) atomic distances, the conformational space of protein segments, which we call the protein segment universe, has been visualized, and three essential coordinate axes, suitable for describing the universe, have been identified. Three essential axes specified radius of gyration, structural symmetry, and separation of hairpin structures from other structures. Among the segments of arbitrary length, 6-22 residues long, the conservation of those axes was uncovered. Further application of PCA to the two largest clusters in the universe revealed local structural motifs. Although some of motifs have already been reported, we identified a possibly novel strand motif. We also showed that a capping box, which is one of the helix capping motifs, was separated into independent subclusters based on the C(alpha) geometry. Implications of the strand motif, which may play a role for protein-protein interaction, are discussed. The currently proposed method is useful for not only mapping the immense universe of protein structures but also identification of structural motifs.     

NK cells can trigger allograft vasculopathy: the role of hybrid resistance in solid organ allografts

Progressive arterial stenosis (cardiac allograft vasculopathy (CAV)) is a leading cause of long-term failure of organ transplants. CAV remains intractable, in part because its mechanisms are insufficiently understood. A central proposition is that MHC-driven alloimmune processes play a necessary role in CAV, as shown by the absolute requirement for histoincompatibility between donor and recipient for its production. Two immunological pathways have been implicated involving reactivity to donor MHC Ags by either T or B cells. In this study, we use a novel system of semiallogeneic cardiac transplants between parental donors and F1 hybrid recipients to provide evidence that NK cells, members of the innate immune system, also contribute to the generation of CAV in mice. This finding marks the first demonstration that the hybrid resistance phenomenon occurs in solid organ allografts. Extension of these experiments to recipients deficient in T cells demonstrates that this third pathway of CAV, the NK cell-triggered pathway, involves the recruitment of T cells not responsive to donor alloantigens. Finally, transplants performed with donors or recipients deficient in IFN-gamma revealed that recipient-derived IFN-gamma is necessary for CAV formation in parental to F1 transplants, suggesting a possible effector mechanism by which NK cells can promote CAV. Together, these results define a previously unknown pathway toward CAV and assign a novel role to NK cells in organ allograft rejection.     

Methylglyoxal induces apoptosis through activation of p38 MAPK in rat Schwann cells

The formation of glucose-derived methylglyoxal (MG), a highly reactive dicarbonyl compound, is accelerated under diabetic conditions. We examined whether MG was capable of inducing apoptosis in Schwann cells (SCs), since recent studies have suggested a potential involvement of apoptotic cell death in the development of diabetic neuropathy. MG induced apoptosis in SCs in a dose-dependent manner, accompanied by a reduction of intracellular glutathione content and activation of the p38 MAPK. Inhibiting the p38 MAPK activation by SB203580 successfully suppressed the MG-induced apoptosis in SCs. Aminoguanidine and N-acetyl-l-cysteine also inhibited the MG-induced p38 MAPK activation and apoptosis along with restoration of the intracellular glutathione content. These results suggest a potential role for MG in SC injury through oxidative stress-mediated p38 MAPK activation under diabetic conditions, and it may serve as a novel insight into therapeutic strategies for diabetic neuropathy.     

Involvement of caspase-9 in execution of the maternal program of apoptosis in Xenopus late blastulae overexpressed with S-adenosylmethionine decarboxylase

We previously demonstrated that overexpression of S-adenosylmethionine decarboxylase (SAMDC) in Xenopus early embryos induces execution of maternal program of apoptosis shortly after midblastula transition, which likely serves as a fail-safe mechanism of early development to eliminate physiologically damaged cells before they entering the gastrula stage. To determine how caspases are involved in this process, we microinjected peptide inhibitors and "dominant-negative forms" of caspase-9 and -1 into Xenopus fertilized eggs, and found that inhibitors of caspase-9, but not caspase-1, completely suppress SAMDC-induced apoptosis. The lysate of SAMDC-overexpressing late blastulae contained activity to cleave in vitro-synthesized [(35)S]procaspase-9, but not [(35)S]procaspase-1, and mRNA for caspase-9, but not caspase-1, occurred abundantly in the unfertilized egg as maternal mRNA. We also found that overexpression of caspase-9 and -1 equally executes the apoptosis, but the apoptosis executed by these mRNAs was only partially rescued by Bcl-2 and rescued embryos did not develop beyond neurula stage. These results indicate that activation of caspase-9 is a key step for execution of the maternally preset program of apoptosis in Xenopus early embryos.     

Does the Number of Diapausing Eggs Laid on Bark Affect the Population Dynamics of the Spider Mite Panonychus mori?

We studied the relationship between number of diapausing eggs produced by the spider mite Panonychus mori and the subsequent population trend for a period of 3 years. Panonychus mori showed a single population density peak on its host plant moonseed, Cocculus trilobus. The position and height of this peak were correlated with the density of diapausing eggs around the moonseed leaf buds produced the winter before. In 1994 the density of diapausing eggs measured in February was 4.3/bud, which was 6–14 times higher than the density of diapausing eggs for the same period in 1995 (0.3/bud) and 1996 (0.7/bud). The subsequent population density peak in 1994 occurred in mid June and was about 2.5 times higher than the peaks in 1995 and 1996, which both occurred early September. Thus, the present study showed a positive correlation between the density of diapausing eggs on the host plant and the start and the extend of the population increase the next growing season. Predators associated with the spider mite population were phytoseiid mites, especially Amblyseius eharai was well synchronized with the spider mite density in 1994. Field observations revealed that P. mori produced diapausing eggs in response to short photoperiod in early October each year, which corresponded with the timing predicted by the critical photoperiod around 13 h at 18°C, as assessed in laboratory trials. Diapause ended by early April when egg hatchability attained about 50% and eggs took 9 days to hatch at 25°C and a 16L:8D photoperiod. Hatching in early April was twice faster than in late February.     

Worker honey bee ovary development: seasonal variation and the influence of larval and adult nutrition

We examined the effect of larval and adult nutrition on worker honey bee (Apis mellifera L.) ovary development. Workers were fed high or low-pollen diets as larvae, and high or low-protein diets as adults. Workers fed low-protein diets at both life stages had the lowest levels of ovary development, followed by those fed high-protein diets as larvae and low- quality diets as adults, and then those fed diets poor in protein as larvae but high as adults. Workers fed high-protein diets at both life stages had the highest levels of ovary development. The increases in ovary development due to improved dietary protein in the larval and adult life stages were additive. Adult diet also had an effect on body mass. The results demonstrate that both carry-over of larval reserves and nutrients acquired in the adult life stage are important to ovary development in worker honey bees. Carry-over from larval development, however, appears to be less important to adult fecundity than is adult nutrition. Seasonal trends in worker ovary development and mass were examined throughout the brood rearing season. Worker ovary development was lowest in spring, highest in mid-summer, and intermediate in fall.     

A Monte Carlo sampling method of amino acid sequences adaptable to given main-chain atoms in the proteins

We have developed a computational method of protein design to detect amino acid sequences that are adaptable to given main-chain coordinates of a protein. In this method, the selection of amino acid types employs a Metropolis Monte Carlo method with a scoring function in conjunction with the approximation of free energies computed from 3D structures. To compute the scoring function, a side-chain prediction using another Metropolis Monte Carlo method was performed to select structurally suitable side-chain conformations from a side-chain library. In total, two layers of Monte Carlo procedures were performed, first to select amino acid types (1st layer Monte Carlo) and then to predict side-chain conformations (2nd layers Monte Carlo). We applied this method to sequence design for the entire sequence on the SH3 domain, Protein G, and BPTI. The predicted sequences were similar to those of the wild-type proteins. We compared the results of the predictions with and without the 2nd layer Monte Carlo method. The results revealed that the two-layer Monte Carlo method produced better sequence similarity to the wild-type proteins than the one-layer method. Finally, we applied this method to neuraminidase of influenza virus. The results were consistent with the sequences identified from the isolated viruses.     

G protein-coupled receptor for diapause hormone, an inducer of Bombyx embryonic diapause

Bombyx diapause hormone was the first chemical substance identified as a maternal control factor that arrests offspring development. However, the molecular mechanisms by which the hormone transduces the signal to the oocyte that induces embryonic diapause immediately after mesoderm segmentation are not fully understood. Here, we describe a cDNA for a G protein-coupled diapause hormone receptor with seven transmembrane domains. Its amino-acid sequence shows a high level of similarity to the receptors of mammalian neuromedin U and insect regulatory peptide, an FXPRL-amide C-terminus. When expressed in a Xenopus oocyte system, the receptor exhibited the highest affinity (EC(50), approximately 70nM) for diapause hormone, when compared with other Bombyx FXPR/KL-amide peptides. Diapause hormone without amidation at the C-terminus, which never induces embryonic diapause in vivo, had no effect in this heterologous expression system. The mRNA is expressed in the ovaries during Bombyx pupal-adult development. These results strongly indicate that the cDNA encodes the diapause hormone receptor.