Heat-shock protein 90 (HSP90) is known to affect a variety of cellular activities. The present study showed that the HSP90-binding agents, geldanamycin, herbimycin A and radicicol, inhibited the murine thymocyte apoptosis induced by dexamethasone and was accompanied by the inhibition of the reduction of the mitochondrial transmembrane potential (ΔΨm). HSP90-binding agents did not inhibit etoposide-induced apoptosis. The inhibition of dexamethasone-induced apoptosis was in part due to the interference of HSP90 with the glucocorticoid receptor, resulting in the inhibition of nuclear translocation of the receptor. The expression of inositol 1, 4, 5-triphosphate receptors, which were shown to be involved in dexamethasone-induced apoptosis, did not participate in the inhibition of apoptosis.

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The aim of this study was to elucidate the cortical regulation of precise finger movements by using magnetoencephalography, with particular emphasis on the late phase of the readiness field. Magnetic brain signals were recorded non-invasively by 306 channel magnetoencephalography during the following two tasks. The first task, a simple task, was to bend the right thumb once as quickly as possible. The second task, a precise one, was to alternately oppose the thumb with the index finger and the middle finger of right hand. In this study, we confirmed that the differences between the two tasks were observed in the late phase of the readiness field, especially in the magnetic field 600 ms before the onset of movement. The activity of the magnetic field of the precise movement task was higher than the activity of the simple movement task. There were obvious differences in the spatial and temporal aspects of the left hemisphere. In the simple movement, the premotor area or motor area was activated in the late phase of the time window. The average latency from the EMG onset was −98.6±34.0 ms (n=5). In the precise movement, the prefrontal area and the SMA were activated in the early and/or middle phases of the time window. The average latency from the EMG onset was −292.0±14.9 ms (n=3) for the prefrontal cortex and −167.8±38.3 ms (n=4) for the SMA. The premotor area or motor area was activated in the late stage of the RF. The average latency from the EMG onset was −111.6±61.4 ms (n=5). Many studies have been performed on the movement-related readiness field. However, the activity of the prefrontal area and the SMA had not previously been studied in the late phase of the readiness field. Our study indicated that the prefrontal area and the SMA played important roles immediately before the onset of precise finger movement. The integration of the prefrontal area, the SMA, and the premotor area is important for the onset of precise finger movement.

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The mean daily fluoride intake in infants was estimated on the basis of their intake of commercial foods for infants in Japan and evaluated in order to establish the effectiveness and safety criteria for water fluoridation, which is practiced as a preventive measure for dental caries suitable in life stages from children to the elderly. Based upon the intakes of foods for infants, the mean daily fluoride intake was estimated to be 0.166 mg in infants aged 3-4 months, 0.202 mg in those aged 5-6 months, and 0.266 mg in those aged 7-8 months. The mean daily fluoride intake per kg of body weight at these ages was in the range of 0.023-0.029 mg/kg, which was about half of the standard daily fluoride intake for infants and children advocated by Ophaug et al., as 0.05-0.07 mg/kg.
From our results, the daily fluoride intake of infants from foods in Japan is estimated to be equivalent to or lower than the values of previous reports in non-fluoridated areas. Consequently, our data support the argument that water fluoridation and the appropriate use of fluoride for dental caries prevention in Japan are needed on the basis of scientific criteria in terms of fluoride exposure related to food intake during tooth formation.

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Detection of single nucleotide polymorphisms (SNPs) and short tandem repeat (STR) polymorphisms by PCR is widely used to analyze degraded DNAs in forensic science. The success of DNA analysis from human remains largely depends on the quality of the template DNA. We examined two SNPs (HLA-DQA1 and ABO) and two STR polymorphisms (VWA and CD4) by SSCP gel or denaturing gel electrophoresis, using two kinds of degraded DNA samples (165 teeth and blood stains contaminated with saliva) derived from the same person and investigated the influence of template DNA degradation on genotyping. As the degradation of DNA proceeds, unbalanced amplification of alleles occurred in the analysis of both SNPs and STRs, followed by allele drop, and further by loss of amplification. Non-target allelic products of STRs were amplified from highly degraded DNA samples; however, false allelic products of SNPs were not amplified from them. Amplification efficiency increased in proportion to the decrease of PCR target size, but reduction of the PCR target sizes also increased the chances of amplifying contaminating DNA, especially in highly degraded DNA specimens. The present results will help investigators to evaluate the genotyping of highly degraded DNA samples in forensic casework.

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Recent studies have shown that invasive and non-invasive strains of Porphyromonas gingivalis can both be isolated from patients with periodontitis. We examined the interaction between an invasive 16-1 P. gingivalis strain and phagocytes obtained from human peripheral blood and guinea pig peritoneal cavity. Phagocytes from human peripheral blood, mainly polymorphonuclear leukocytes (PMNs) isolated by centrifugation in Ficoll Hypaque, and macrophages collected from the peritoneal cavity of guinea pigs, were exposed to P. gingivalis cells. After this exposure, greater numbers of the non-invasive P. gingivalis ATCC 33277 were observed in human PMNs and guinea pig macrophages compared with the invasive P. gingivalis 16-1. Electron microscopic observations showed that invasive 16-1 within phagosomes in human PMNs and guinea pig macrophages retained their surface fibrous structures as well as their outer membranes. Electron microscopic examination showed that destruction and damage to the cell membranes and inner structures were clear in human PMNs and guinea pig macrophages after exposure to invasive 16-1 for 6 and 24 hours; this was a clear difference from exposure to the non-invasive ATCC 33277. Release of lactate dehydrogenase (LDH) activities into the culture supernatant of PMNs after exposure to the invasive 16-1 for 4 and 6 hours was significantly greater than that after exposure to the non-invasive ATCC 33277 (p<0.05). On the other hand, the LDH activity after exposure for 21 hours to the invasive 16-1 was significantly lower than that of untreated cells and cells after exposure to the non-invasive ATCC 33277 strain (p<0.05). The PMN viabilities after exposure to cells of the invasive 16-1 for 3, 4, and 6 hours as evaluated by trypan blue staining were similar to those after exposure to cells of the non-invasive ATCC 33277, but that after exposure to the invasive 16-1 strain for 21 hours was significantly lower than that after exposure to cells of the noninvasive ATCC 33277 strain.

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The postsynaptic actions of exogenously applied adenosine 5′-triphosphate (ATP) were investigated in nucleus tractus solitarius (NTS) of the rat. Whole cell patch-clamp recordings were used to examine the regulation of voltage-dependent Ca²⁺ channels (VDCCs) currents (I_Ca) by ATP in freshly dissociated NTS. Application of ATP inhibited I_Ca from −905 pA to −741 pA. In addition to this inhibition, application of ATP facilitated I_Ca from −941 pA to −1, 094 pA in other neurons. The data presented here demonstrate for the first time that ATP has both inhibitory and facilitative effects on I_Ca in NTS. It can be considered that ATP acts as a neurotransmitter in the NTS by having multiple regulatory effects on VDCCs.

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