Identification and estimation algorithm for stochastic neural system. II

The algorithm for identifying the stochastic neural system and estimating the system process which reflects the dynamics of the neural network are presented in this papar. The analogous algorithm has been proposed in our preceding paper (Nakao et al., 1984), which was based on the randomly missed observations of a system process only. Since the previous algorithm mentioned above was subject to an unfavorable effect of consecutively missed observations, to reduce such an effect the algorithm proposed here is designed additionally to observe an intensity process in a neural spike train as the information for the estimation.The algorithm is constructed with the extended Kalman filters because it is naturally expected that a nonlinear and time variant structure is necessary for the filters to realize the observation of an intensity process by means of mapping from a system process to an intensity process. The performance of the algorithm is examined by applying it to some artificial neural systems and also to cat's visual nervous systems. The results in these applications are thought to prove the effectiveness of the algorithm proposed here and its superiority to the algorithm proposed previously.     

Fluorescent-labeled oligonucleotides that exhibit a measurable signal in the presence of complementary DNA.

Oligonucleotide derivatives with a fluorescent dye were designed for exhibiting a measurable signal only when they bind to complementary DNA in aqueous solution. The oligonucleotide with a dansyl group at the specific 2'-sugar residue was synthesized by using the protected 2'-dansylaminouridine phosphorobisamidite. The dansyl-oligonucleotide conjugate binds to its complementary DNA to form duplex with a normal stability and exhibits enhanced fluorescence together with a blue-shift in emission maxima after the hybridization. Another possible candidate involved the use of pyrene-excimer emission upon forming ternary complex between two pyrene-labeled oligonucleotide probes with target DNA. A new and general method for introduction of a pyrene fluorophore into the 3'- or 5'-terminal hydroxyl group of oligonucleotides via different linkers was developed.     

Calcium concentration in brains from multiple sclerosis patients

Calcium (Ca) concentrations were studied in the central nervous system (CNS) of four patients with definite multiple sclerosis (MS, average age 49 yr) and five controls (average age 68 yr). The Ca concentration was determined by neutron activation analysis in autopsy samples taken from the 26 subanatomical regions of CNS tissues. Although the mean Ca concentration in the 26 CNS regions combined was higher in the four MS patients than in the controls, the content of white matter was lower. Whether or not this significantly lower Ca concentration found in the white matter of MS patients plays an important role in the demyelinating process remains unclear, although that lower concentration seems not be age dependent, but MS specific.     

A double-blind,placebo-controlled,randomised clinical study of the effect of pork collagen peptide supplementation on atherosclerosis in healthy older individuals

We examined whether baPWV could be affected by pork collagen peptide (CP) ingestion. Seventy subjects were randomized into two groups (2.5 g/day CP and 2.5 g/day placebo). A significant reduction in baPWV was observed in the CP group compared to the placebo group. This study demonstrated that pork CP may contribute to the prevention of atherosclerosis in elderly.     

Nitric oxide-induced salt stress tolerance in plants: ROS metabolism,signaling, and molecular interactions

Nitric oxide (NO), a non-charged, small, gaseous free-radical, is a signaling molecule in all plant cells. Several studies have proposed multifarious physiological roles for NO, from seed germination to plant maturation and senescence. Nitric oxide is thought to act as an antioxidant, quenching ROS during oxidative stress and reducing lipid peroxidation. NO also mediates photosynthesis and stomatal conductance and regulates programmed cell death, thus providing tolerance to abiotic stress. In mitochondria, NO participates in the electron transport pathway. Nitric oxide synthase and nitrate reductase are the key enzymes involved in NO-biosynthesis in aerobic plants, but non-enzymatic pathways have been reported as well. Nitric oxide can interact with a broad range of molecules, leading to the modification of protein activity, GSH biosynthesis, S-nitrosylation, peroxynitrite formation, proline accumulation, etc., to sustain stress tolerance. In addition to these interactions, NO interacts with fatty acids to form nitro-fatty acids as signals for antioxidant defense. Polyamines and NO interact positively to increase polyamine content and activity. A large number of genes are reprogrammed by NO; among these genes, proline metabolism genes are upregulated. Exogenous NO application is also shown to be involved in salinity tolerance and/or resistance via growth promotion, reversing oxidative damage and maintaining ion homeostasis. This review highlights NO-mediated salinity-stress tolerance in plants, including NO biosynthesis, regulation, and signaling. Nitric oxide-mediated ROS metabolism, antioxidant defense, and gene expression and the interactions of NO with other bioactive molecules are also discussed. We conclude the review with a discussion of unsolved issues and suggestions for future research.     

Reconstruction of the Human Colon Epithelium In Vivo

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Mouse Homolog of Poliovirus Receptor-Related Gene 2 Product, mPRR2, Mediates Homophilic Cell Aggregation

Poliovirus receptor (PVR) is a cell surface glycoprotein that belongs to the immunoglobulin superfamily. Although MPH was initially reported as the mouse homolog of human PVR, recent data strongly suggest that MPH is the mouse homolog of human PRR2, a PVR-related gene 2 product, and not that of human PVR. Thus MPH is renamed mPRR2 in this study. Physiological functions of the PVR-related gene products have not been elucidated, although PVR has been well characterized as the poliovirus receptor. In this study, a possible function of mPRR2 (MPH), which is not a functional receptor for poliovirus, was investigated. Mouse L cells expressing mPRR2 were prepared. Those mouse cells showed a higher activity of cell aggregation than the parental mouse L cells. Enhancement of cell aggregation was also observed for insect Sf9 cells infected with recombinant baculovirus carrying mPRR2 cDNA. On the other hand, L cells expressing human PVR or monkey PVR (AGMα1 or AGMα2) did not show increased cell aggregation. The cell aggregation activity of L cells expressing mPRR2 was inhibited by the addition of anti-mPRR2 monoclonal antibodies or a soluble mPRR2 molecule produced by the baculovirus expression system. An immunofluorescence study revealed that mPRR2 protein was localized to the cell–cell contact sites between cells expressing mPRR2. A similar localization of mPRR2 was observed for intrinsic mPRR2 molecules of the mouse neuroblastoma cell line NS20Y. The contact site-specific localization of mPRR2 was not observed on the border between mPRR2-expressing and nonexpressing HeLa cells. Furthermore, mPRR2 proteins directly bound to each otherin vitro.mPRR2 was detected on various types of cultured cells of mouse origin and in various mouse tissues. These results suggest that mPRR2 is an intercellular adhesion molecule with a homophilic binding manner.