Prostaglandin E(2) inhibits IL-18-induced ICAM-1 and B7.2 expression through EP2/EP4 receptors in human peripheral blood mononuclear cells

Costimulatory molecules play important roles in immune responses. In the present study we investigated the effects of PGE(2) on the expression of ICAM-1, B7.1, and B7.2 on monocytes in IL-18-stimulated PBMC using FACS analysis. Addition of PGE(2) to PBMC inhibited ICAM-1 and B7.2 expression elicited by IL-18 in a concentration-dependent manner. We examined the involvement of four subtypes of PGE(2) receptors, EP1, EP2, EP3, and EP4, in the modulatory effect of PGE(2) on ICAM-1 and B7.2 expression elicited by IL-18, using subtype-specific agonists. ONO-AE1-259-01 (EP2R agonist) inhibited IL-18-elicited ICAM-1 and B7.2 expression in a concentration-dependent manner with a potency slightly less than that of PGE(2), while ONO-AE1-329 (EP4R agonist) was much less potent than PGE(2). The EP2/EP4R agonist 11-deoxy-PGE(1) mimicked the effect of PGE(2) with the same potency. ONO-D1-004 (EP1R agonist) and ONO-AE-248 (EP3R agonist) showed no effect on IL-18-elicited ICAM-1 or B7.2 expression. These results indicated that EP2 and EP4Rs were involved in the action of PGE(2). Dibutyryl cAMP and forskolin down-regulated ICAM-1 and B7.2 expression in IL-18-stimulated monocytes. As EP2 and EP4Rs are coupled to adenylate cyclase, we suggest that PGE(2) down-regulates IL-18-induced ICAM-1 and B7.2 expression in monocytes via EP2 and EP4Rs by cAMP-dependent signaling pathways. The fact that anti-B7.2 as well as anti-ICAM-1 Ab inhibited IL-18-induced cytokine production implies that PGE(2) may modulate the immune response through regulation of the expression of particular adhesion molecules on monocytes via EP2 and EP4Rs.     

Newly developed waist actigraphy and its sleep/wake scoring algorithm

The purpose of this study was to formulate an algorithm for assessing sleep/waking from activity intensities measured with a waist-worn actigraphy, the Lifecorder PLUS (LC; Suzuken Co. Ltd., Nagoya, Japan), and to test the validity of the algorithm. The study consisted of 31 healthy subjects (M/F = 20/11, mean age 31.7 years) who underwent one night of simultaneous measurement of activity intensity by LC and polysomnography (PSG). A sleep(S)/wake(W) scoring algorithm based on a linear model was determined through discriminant analysis of activity intensities measured by LC over a total of 235 h and 56 min and the corresponding PSG-based S/W data. The formulated S/W scoring algorithm was then used to score S/W during the monitoring epochs (2 min each, 7078 epochs in total) for each subject. The mean agreement rate with the corresponding PSG-based S/W data was 86.9%, with a mean sensitivity (sleep detection) of 89.4% and mean specificity (wakefulness detection) of 58.2%. The agreement rates for the individual stages of sleep were 60.6% for Stage 1, 89.3% for Stage 2, 99.2% for Stage 3 + 4, and 90.1% for Stage REM. These results demonstrate that sleep/wake activity in young to middle-aged healthy subjects can be assessed with a reliability comparable to that of conventional actigraphy through LC waist actigraphy and the optimal S/W scoring algorithm.

     

Impaired Ca2+ store functions in skeletal and cardiac muscle cells from sarcalumenin-deficient mice

Sarcalumenin (SAR), specifically expressed in striated muscle cells, is a Ca2+-binding protein localized in the sarcoplasmic reticulum (SR) of the intracellular Ca2+ store. By generating SAR-deficient mice, we herein examined its physiological role. The mutant mice were apparently normal in growth, health, and reproduction, indicating that SAR is not essential for fundamental muscle functions. SAR-deficient skeletal muscle carrying irregular SR ultrastructures retained normal force generation but showed slow relaxation phases after contractions. A weakened Ca2+ uptake activity was detected in the SR prepared from mutant muscle, indicating that SAR contributes to Ca2+ buffering in the SR lumen and also to the maintenance of Ca2+ pump proteins. Cardiac myocytes from SAR-deficient mice showed slow contraction and relaxation accompanied by impaired Ca2+ transients, and the mutant mice exhibited a number of impairments in cardiac performance as determined in electrocardiography, ventricular catheterization, and echocardiography. The results obtained demonstrate that SAR plays important roles in improving the Ca2+ handling functions of the SR in striated muscle.     

Targeted disruption of the neurochondrin/norbin gene results in embryonic lethality

Neurochondrin/norbin is a cytoplasmic protein involved in dendrite outgrowth. The expression of the gene has been restricted to neural, bone, and chondral tissues. To identify the functions of the gene in vivo, we have generated mice with a disrupted mutation in the neurochondrin/norbin gene. Histological analysis of heterozygous mutant mice indicates the possibility of specific functions of neurochondrin/norbin in chondrocyte differentiation. We defined the expression patterns of neurochondrin/norbin-lacZ fusion protein in the central nervous system. In the developing olfactory bulb, beta-galactosidase activity was detected in the mantle layer at 12.5 dpc and the strongest activity was detected in the presumptive mitral or tufted cell layer at 15.5 dpc. beta-Galactosidase activity was also detected in the lateral choroid plexus. In homozygous (-/-) mutant mice, the disruption of the neurochondrin/norbin gene leads to early embryonic death between 3.5 and 6.5 dpc. This result indicates that neurochondrin/norbin gene function is essential for the early embryogenesis.     

Novel algorithm for automated genotyping of microsatellites

Microsatellites or short tandem repeats (STRs) are abundant in the human genome with easily assayed polymorphisms, providing powerful genetic tools for mapping both Mendelian and complex traits. Microsatellite genotyping requires detection of the products of polymerase chain reaction (PCR) amplification by electrophoresis, and analysis of the peak data for discrimination of the true allele. A high-throughput genotyping approach requires computer-based automation at both the detection and analysis phases. In order to achieve this, complicated peak patterns from individual alleles must be interpreted in order to assign alleles. Previous methods consider limited types of noise peaks and cannot provide enough accuracy. By pattern recognition of various types of noise peaks, such as stutter peaks and additional peaks, we have achieved an overall average accuracy of 94% for allele calling in our actual data. Our algorithm is crucial for a high-throughput genotyping system for microsatellite markers by reducing manual editing and human errors.     

Assessment of genetic diversity in a Morus germplasm collection using fluorescence-based AFLP markers

To meet various breeding objectives and to conserve the existing genetic resources of mulberry for future use, the present study was undertaken to investigate the amount of genetic diversity and to establish the relationships between mulberry genotypes using fluorescence-based AFLP markers. Genetic diversity was estimated in 45 mulberry accessions from different eco-geographic regions of Japan and other parts of the world. Five primer combinations amplified an average of 110 AFLP markers per primer combination, ranging in size from 35 to 500 bp. A high degree of polymorphism was revealed by these combinations that ranged from 69.7 to 82.3% across all the genotypes studied. Several rare genotype-specific bands were also identified which could be effectively utilized to distinguish different genotypes. The wide range in genetic similarity coefficients (0.58–0.99) indicated that the mulberry germplasm collection represents a genetically diverse popu-lation. The phenetic dendrogram generated by the UPGMA method grouped 45 accessions into four major clusters, which was in agreement with the results from conventional methods. Clustering of some genotypes into strictly separate groups was not readily apparent and no clear interrelationships could be depicted, in spite of their different geographic origin. In addition, AFLP analysis provided sufficient polymorphism for DNA typing and contributed additional insights into the genetic structure of the mulberry germplasm. These results will help in the formulation of appropriate strategies for conservation and variety improvement in mulberry, for which little or no knowledge of genetic diversity is currently available. Received: 30 December 1999 / Accepted: 14 March 2000     

Neural network development in late adolescents during observation of risk-taking action

Emotional maturity and social awareness are important for adolescents, particularly college students beginning to face the challenges and risks of the adult world. However, there has been relatively little research into personality maturation and psychological development during late adolescence and the neural changes underlying this development. We investigated the correlation between psychological properties (neuroticism, extraversion, anxiety, and depression) and age among late adolescents (n?=?25, from 18 years and 1 month to 22 years and 8 months). The results revealed that late adolescents became less neurotic, less anxious, less depressive and more extraverted as they aged. Participants then observed video clips depicting hand movements with and without a risk of harm (risk-taking or safe actions) during functional magnetic resonance imaging (fMRI). The results revealed that risk-taking actions elicited significantly stronger activation in the bilateral inferior parietal lobule, temporal visual regions (superior/middle temporal areas), and parieto-occipital visual areas (cuneus, middle occipital gyri, precuneus). We found positive correlations of age and extraversion with neural activation in the insula, middle temporal gyrus, lingual gyrus, and precuneus. We also found a negative correlation of age and anxiety with activation in the angular gyrus, precentral gyrus, and red nucleus/substantia nigra. Moreover, we found that insula activation mediated the relationship between age and extraversion. Overall, our results indicate that late adolescents become less anxious and more extraverted with age, a process involving functional neural changes in brain networks related to social cognition and emotional processing. The possible neural mechanisms of psychological and social maturation during late adolescence are discussed.     

Intermediate frequency magnetic fields do not have mutagenic, co-mutagenic or gene conversion potentials in microbial genotoxicity tests

We used bacterial mutation and yeast genotoxicity tests to evaluate the effects of intermediate frequency (IF; 2 kHz, 20 kHz and 60 kHz) magnetic fields (MFs) on mutagenicity, co-mutagenicity and gene conversion. We constructed a Helmholtz type exposure system that generated vertical and sinusoidal IF MFs, such as 0.91 mT at 2 kHz, 1.1 mT at 20 kHz and 0.11 mT at 60 kHz. Mutagenicity, co-mutagenicity and gene conversion assays were performed for each of the three MF exposure conditions. Mutagenicity testing was performed in four strains of Salmonella typhimurium (TA98, TA100, TA1535 and TA1537) and two strains of Escherichia coli (WP2 uvrA and WP2 uvrA/pKM101) to cover a wide spectrum of point mutations. For co-mutagenicity tests, we used four sensitive test strains (TA98, TA100, WP2 uvrA and WP2 uvrA/pKM101) with five chemical mutagens (t-butyl hydroperoxide (BH, a hydroxyl free radical precursor), 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide (AF2) and N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG, DNA reactive reagents), benz[a]pyrene (BaP) and 2-aminoanthracene (2AA, DNA reactive promutagens). Gene conversion testing was performed in the yeast test strain, Saccharomyces cerevisiae XD83. We also examined the effects on the repair process of DNA damage by UV irradiation. No statistically significant effects were observed between exposed and control groups in any of the genotoxicity tests, indicating that the IF MFs (0.91 mT at 2 kHz, 1.1 mT at 20 kHz or 0.11 mT at 60 kHz) do not have mutagenic or co-mutagenic potentials for the chemical mutagens tested under these experimental conditions. Our findings also indicate that these IF MFs do not induce gene conversion or affect the repair process of DNA damage in eukaryotic cells.