Railway suicide attempts are associated with amount of sunlight in recent days.

BACKGROUND: To assess the relationship between hours of sunlight and railway suicide attempts, 3-7 days before these attempts. METHODS: All railway suicide attempts causing railway suspensions or delays of 30 min or more between 2002 and 2006. We used a linear probability model to assess this relationship. This study was conducted at Tokyo, Kanagawa, and Osaka prefectures in Japan. Data were collected from the railway delay incident database of the Japanese Railway Technical Research Institute and public weather database of the Japan Meteorological Agency. RESULTS: About 971 railway suicides attempts occurred between 2002 and 2006 in Tokyo, Kanagawa, and Osaka. Less sunlight in the 7 days leading up to the railway suicide attempts was associated with a higher proportion of attempts (p=0.0243). Sunlight over the 3 days before an attempt had a similar trend (p=0.0888). No difference was found in sunlight hours between the days with (median: 5.6 [IQR: 1.1-8.8]) and without (median: 5.7 [IQR: 1.0-8.9]) railway suicide attempts in the evening. Finally, there was no apparent correlation between the railway suicide attempts and the monthly average sunlight hours of the attempted month or those of a month before. LIMITATIONS: Railway suicides were not the main suicidal methods in Japan, CONCLUSIONS: We observed an increased proportion of railway suicide attempts after several days without sunlight. Light exposure (blue light or bright white light) in trains may be useful in reducing railway suicides, especially when consecutive days without sunshine are forecasted.

[The potential of dual-energy virtual monochromatic imaging in reducing renal cyst pseudoenhancement: a phantom study].

Renal cyst pseudoenhancement, an artifactual increase of computed tomography (CT) attenuation for cysts with increased iodine concentrations in the renal parenchyma, complicates the classification of cysts and may thus lead to the mischaracterization of a benign non-enhancing lesion as an enhancing mass. The purpose of this study was to use a phantom model to assess the ability of dual-energy virtual monochromatic imaging to reduce renal pseudoenhancement. A water-filled cylindrical cyst model suspended in varying concentrations of iodine solution, to simulate varying levels of parenchymal enhancement, was scanned with a dual-energy CT scanner using the following three scanning protocols with different combinations of tube voltage: 80 and 140 kV; 80 and 140 kV with tin filter; and 100 and 140 kV with tin filter. Virtual monochromatic images were then synthesized for each dual-energy scan. Single-energy scan with a tube voltage of 120 kV was also performed to obtain polychromatic images as controls. Mean attenuation values (in Hounsfield units) of cyst proxies were measured on both polychromatic and virtual monochromatic images. Pseudoenhancement was considered to be present when the cyst attenuation level increased by more than 10 HU as the background iodine concentration increased from 0.0% to 0.4%, 1.5%, or 2.5%. Our results revealed that pseudoenhancement was not observed on any of the monochromatic images, but appeared on polychromatic images at a background iodine concentration of 2.5%. We thus conclude that dual-energy virtual monochromatic images have a potential to reduce renal pseudoenhancement.

Phylogenetic relationships of three species within the family Heligmonellidae (Nematoda; Heligmosomoidea) from Japanese rodents and a lagomorph based on the sequences of ribosomal DNA internal transcribed spacers, ITS-1 and ITS-2.

Nematodes of the family Heligmonellidae (Heligmosomoidea; Trichostrongylina) reside in the digestive tracts of rodents and lagomorphs. Although this family contains large numbers of genera and species, genetic information on the Heligmonellidae is very limited. We collected and isolated adult worms of three species in Japan that belong to the family Heligmonellidae, namely Heligmonoides speciosus (Konno, 1963) Durette-Desset, 1970 (Hs) from Apodemus argenteus, Orientostrongylus ezoensis Tada, 1975 (Oe) from Rattus norvegicus and Lagostrongylus leporis (Schulz, 1931) (Ll) from Pentalagus furnessi, and sequenced the entire internal transcribed spacer regions, ITS-1 and ITS-2 of ribosomal DNA. ITS-1 of Hs, Oe and Ll was 426, 468 and 449 bp in length, and had a G+C content of about 41, 41 and 37 %, respectively. ITS-2 of Hs, Oe and Ll was 297, 319 and 276 bp in length and had a G+C content of about 38, 40 and 28%, respectively. The data of Hs, Oe and Ll were compared with those of two other known species within the family Heligmonellidae, Calorinensis minutus (Dujardin, 1845) (Cm) and Nippostrogylus brasiliensis (Travassos, 1914) (Nb), and with those of two species of Heligmosomidae (Heligmosomoidea), Heligmosomoides polygyrus bakeri and Ohbayashinema erbaevae. Phylogenetic analysis placed Hs, Oe and Ll in the same clade with Cm and Nb, forming a Heligmonellidae branch in both ITS-1 and ITS-2, separate from the Heligmosomoidea branch. These results demonstrated that the ITS-1 and ITS-2 sequences are useful for differentiating the Heligmonellidae nematode species. This study is the first to describe the ITS-1 and ITS-2 sequences of Hs, Oe and Ll.

Effects of synaptotagmin 2 on membrane fusion between liposomes that contain SNAREs involved in exocytosis in mast cells.

Mast cells play a pivotal role in allergic responses. Antigen stimulation causes elevation of the intracellular Ca(2+) concentration, which triggers the exocytotic release of inflammatory mediators such as histamine. Recent research, including our own, has revealed that SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins such as syntaxin-3, -4, SNAP-23, and VAMP-8 are involved in exocytosis. Although exocytosis in mast cells is Ca(2+) dependent, the target molecule that interacts with Ca(2+) is not clear. Synaptotagmin is a Ca(2+) sensor and regulates exocytosis in neuronal cells. However, the role of synaptotagmin 2, a member of the synaptotagmin family, in exocytosis in mast cells remains controversial. In this study, we investigated the role of synaptotagmin 2 by a liposome-based fusion assay. SNARE proteins (SNAP-23, syntaxin-3, VAMP-8) and synaptotagmin 2 were expressed in Escherichia coli and purified as GST-tagged or His-tagged fusion proteins. These SNARE proteins were incorporated by a detergent dialysis method. Membrane fusion between liposomes was monitored by fluorescence resonance energy transfer between fluorescent-labeled phospholipids. In the presence of Ca(2+), low synaptotagmin 2 concentration inhibited membrane fusion between SNARE-containing liposomes, while high synaptotagmin 2 concentration enhanced membrane fusion. This enhancement required phosphatidylserine as a membrane component. These results suggest that synaptotagmin 2 regulates membrane fusion of SNARE-containing liposomes involved in exocytosis in mast cells, and that this regulation is dependent on synaptotagmin 2 concentration, Ca(2+), and phosphatidylserine.

Platelet high-density lipoprotein activates transferrin-derived phagocytosis activators, MAPPs, following thrombin digestion.

Macromolecular activators of phagocytosis from platelets (MAPPs), transferrin-derived phagocytosis activators released from platelets, activate leukocytic phagocytosis via Fcγ receptors. It has been found that MAPPs can be prepared using stored platelets or their lysate. Using this artificial MAPP production system, it has been found that they can be produced from precursors (tetrameric and dimeric transferrins) following reaction with a low-molecular-weight (LMW) activator of MAPPs, which is liberated from a high-molecular-weight activator of MAPP (HMW activator) by reaction with thrombin. In this study, the HMW activator in platelet lysate was characterized by assaying phagocytosis of washed neutrophils. In an ultracentrifugation study of the platelet lysate, HMW activator activity was observed in the fraction corresponding to the density of high-density lipoprotein (HDL). The activity was observed in the apolipoproteins obtained from the HDL fraction. Among the apolipoproteins tested only apolipoprotein CIII showed the activity to produce MAPP in vitro. Affinity chromatography of the apolipoproteins from the HDL fraction of the platelet lysate using an anti-apolipoprotein CIII column revealed that the substance that binds with the antibody showed MAPP-forming activity. In a gel filtration study of thrombin-treated apolipoprotein CIII, a peak of LMW activator activity was observed for fractions with a molecular size smaller than that of apolipoprotein CIII. Finally, MAPP-forming activity of HDL obtained from the plasma was examined. MAPP was formed only when delipidized HDL was used. In conclusion, it is suggested that platelet HDL is the HMW activator and that this activation is achieved via apolipoprotein CIII after thrombin reaction in platelets.

A novel underuse model shows that inactivity but not ovariectomy determines the deteriorated material properties and geometry of cortical bone in the tibia of adult rats.

Our goal in this study was to determine to what extent the physiologic consequences of ovariectomy (OVX) in bones are exacerbated by a lack of daily activity such as walking. We forced 14-week-old female rats to be inactive for 15 weeks with a unique experimental system that prevents standing and walking while allowing other movements. Tibiae, femora, and 4th lumbar vertebrae were analyzed by peripheral quantitative computed tomography (pQCT), microfocused X-ray computed tomography (micro-CT), histology, histomorphometry, Raman spectroscopy, and the three-point bending test. Contrary to our expectation, the exacerbation was very much limited to the cancellous bone parameters. Parameters of femur and tibia cortical bone were affected by the forced inactivity but not by OVX: (1) cross-sectional moment of inertia was significantly smaller in Sham-Inactive rat bones than that of their walking counterparts; (2) the number of sclerostin-positive osteocytes per unit cross-sectional area was larger in Sham-Inactive rat bones than in Sham-Walking rat bones; and (3) material properties such as ultimate stress of inactive rat tibia was lower than that of their walking counterparts. Of note, the additive effect of inactivity and OVX was seen only in a few parameters, such as the cancellous bone mineral density of the lumbar vertebrae and the structural parameters of cancellous bone in the lumbar vertebrae/tibiae. It is concluded that the lack of daily activity is detrimental to the strength and quality of cortical bone in the femur and tibia of rats, while lack of estrogen is not. Our inactive rat model, with the older rats, will aid the study of postmenopausal osteoporosis, the etiology of which may be both hormonal and mechanical.

Increased social interaction in mice deficient of the striatal medium spiny neuron-specific phosphodiesterase 10A2.

Cyclic nucleotide phosphodiesterase 10A (PDE10A) is a member of phosphodiesterase families that degrade cAMP and/or cGMP in distinct intracellular sites. PDE10A has a dual activity on hydrolysis of both cAMP and cGMP, and is prominently expressed in the striatum and the testis. Previous studies suggested that PDE10A is involved in regulation of locomotor activity and potentially related to psychosis, but concrete physiological roles of PDE10A remains elusive yet. In this study, we genetically inactivated PDE10A2, a prominent isoform of PDE10A in the brain, in mice, and demonstrate that PDE10A2 deficiency results in increased social interaction without any major influence on different other behaviors, along with increased levels of striatal cAMP. We also demonstrate that PDE10A2 is selectively distributed in medium spiny neurons, but not interneurons, of the striatal complex. Thus, our results establish a physiological role for PDE10A2 in regulating cAMP pathway and social interaction, and suggest that cAMP signaling cascade in striatal medium spiny neurons might be involved in regulating social interaction behavior in mice.

Environmental and behavioral conditions of bathing among elderly Japanese.

This study investigated the bathing conditions of elderly Japanese, and sought to find factors relating to regional differences in death rates from bathtub accidents. A questionnaire survey was carried out in 11 areas of Japan. Questionnaires including questions regarding the length of time since houses had been built, types of facilities, and subjects' indoor thermal sensations and behavior while bathing were distributed to detached houses in each area twice, once in summer and once in winter. Completed questionnaires were collected from approximately 160 elderly people over 65 years old. Information regarding thermal sensations of rooms in winter revealed that a prefabricated bath and insulating window glass eased the cold in the bathroom. Unexpectedly, more subjects in the southern region than in the northern region reported being cold or a little cold while bathing in winter. In the present study, thermal sensations and behaviors while bathing seemed to be more affected by facilities and the location of houses than by the sex and age of the subjects.

Inducible expression of retrograde transynaptic genetic tracer in mice.

A key step towards understanding the development and function of the central nervous system is by characterizing the connections between neurons. Tetanus toxin C fragment (TTC) is transynaptically and retrogradely transported without the toxin's pathogenic effect, and therefore, recently it has been used as a genetic tracer combined with beta-galactosidase or green fluorescent protein. Here, we introduce a new fusion construct, APTTC, consisting of the truncated human placental alkaline phosphatase with TTC, and generating the transgenic mouse line, (tetracycline operator) tetO-APTTC, for inducible expression of APTTC regulated by tetO. We demonstrate that APTTC is transported retrogradely and transynaptically, and allows us to robustly visualize the inputs of the expressing neurons when transgenetically expressed in mice, exemplified in the striatal neuronal circuit. Therefore, tetO-APTTC transgenic mouse line can be widely used for visualization of neuronal connectivity when combined with mice carrying tetracycline-controlled transactivator (tTA) in any specific neurons.

Transgenic expression of Cre recombinase in mitral/tufted cells of the olfactory bulb.

Olfactory information is conveyed from the periphery to the olfactory cortices through mitral and tufted (M/T) cells in the olfactory bulb. A mouse with a specific expression of Cre recombinase in M/T cells is essential for genetic marking of M/T cells and manipulating their properties. Protocadherin 21 (Pcdh21) expression is highly restricted to M/T cells. Here we report a transgenic mouse line, Pcdh21-Cre, in which 10-kb mouse Pcdh21 promoter drives the expression of Cre recombinase. In Pcdh21-Cre mice, Cre recombinase activity is predominantly detected in M/T cells, visualized with the anti-CFP immunostaining in offspring of a cross between Pcdh21-Cre and the reporter Rosa26-loxP-stop-loxP-CFP strain. These results demonstrate that the 10-kb Pcdh21 promoter can drive transcription in M/T cells and Pcdh21-Cre mice can be used to excise floxed DNA fragments in M/T cells, which provides a valuable tool to reveal the structure and function of the central olfactory circuits.

In vivo administration of 1,25-dihydroxyvitamin D3 suppresses the expression of RANKL mRNA in bone of thyroparathyroidectomized rats constantly infused with PTH.

It is known that pharmacological or toxic doses of vitamin D induce bone resorption both in vivo and in vitro, whereas physiological doses of the vitamin have a protective effect on bone in vivo. To investigate the discrepancies of the dose-dependent effect of vitamin D on bone resorption, we examined the in vivo effect of 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] on the expression of the receptor activator of nuclear factor-kappaB (NF-kappaB) ligand (RANKL) and osteoprotegerin (OPG) mRNAs in bone of thyroparathyroidectomized (TPTX) rats infused with or without parathyroid hormone (PTH). Continuous infusion of 50 ng/h of PTH greatly increased the expression of RANKL mRNA in bone of TPTX rats. Expression of OPG mRNA was not altered by PTH infusion. When graded doses of 1,25(OH)(2)D(3) was daily administered orally for 14 days to normocalcemic TPTX rats constantly infused with PTH, 0.01 and 0.1 microg/kg of 1,25(OH)(2)D(3) inhibited the PTH-induced RANKL mRNA expression, but 0.5 microg/kg of the vitamin did not inhibit it. Regulator of G protein signaling-2 (RGS-2) gene expression was suppressed by 1,25(OH)(2)D(3) dose-dependently, but PTH/PTHrP receptor mRNA expression was not altered. Bone morphometric analyses revealed that 1,25(OH)(2)D(3) suppressed PTH-induced osteoclast number in vivo. These results suggest that pharmacological or toxic doses of 1,25(OH)(2)D(3) stimulate bone resorption by inducing RANKL, but a certain range of physiological doses of the vitamin inhibit PTH-induced bone resorption, the latter mechanism appeared to be mediated, at least in part, by the suppression of the PTH/PTHrP receptor-mediated signaling.