Demonstration of wavelength-scan-free action spectroscopy in pump/probe measurement with supercontinuum pump light.

We devise and introduce the principle of wavelength-scan-free spectroscopy for the pump light in pump/probe measurement (action spectroscopy) using supercontinuum light; we demonstrate its implementation by measuring transmission spectra. We use the supercontinuum light noise as a code in order to discriminate wavelength. We extract the stimulation at the desired wavelength by correlating the noise at that wavelength observed separately and the observed total stimulation carried by the probe light. The wavelength-scan-free spectroscopy is enabled with a simultaneous procedure for multiple wavelengths.

The extreme light infrastructure-nuclear physics (ELI-NP) facility: new horizons in physics with 10 PW ultra-intense lasers and 20 MeV brilliant gamma beams.

The European Strategy Forum on Research Infrastructures (ESFRI) has selected in 2006 a proposal based on ultra-intense laser fields with intensities reaching up to 1022-1023 W cm-2 called 'ELI' for Extreme Light Infrastructure. The construction of a large-scale laser-centred, distributed pan-European research infrastructure, involving beyond the state-of-the-art ultra-short and ultra-intense laser technologies, received the approval for funding in 2011-2012. The three pillars of the ELI facility are being built in Czech Republic, Hungary and Romania. The Romanian pillar is ELI-Nuclear Physics (ELI-NP). The new facility is intended to serve a broad national, European and International science community. Its mission covers scientific research at the frontier of knowledge involving two domains. The first one is laser-driven experiments related to nuclear physics, strong-field quantum electrodynamics and associated vacuum effects. The second is based on a Compton backscattering high-brilliance and intense low-energy gamma beam (<20 MeV), a marriage of laser and accelerator technology which will allow us to investigate nuclear structure and reactions as well as nuclear astrophysics with unprecedented resolution and accuracy. In addition to fundamental themes, a large number of applications with significant societal impact are being developed. The ELI-NP research centre will be located in Magurele near Bucharest, Romania. The project is implemented by 'Horia Hulubei' National Institute for Physics and Nuclear Engineering (IFIN-HH). The project started in January 2013 and the new facility will be fully operational by the end of 2019. After a short introduction to multi-PW lasers and multi-MeV brilliant gamma beam scientific and technical description of the future ELI-NP facility as well as the present status of its implementation of ELI-NP, will be presented. The science and examples of societal applications at reach with these electromagnetic probes with much improved performances provided at this new facility will be discussed with a special focus on day-one experiments and associated novel instrumentation.

Comparison of four enrichment broths for the detection of non-O157 Shiga-toxin-producing Escherichia coli O91, O103, O111, O119, O121, O145 and O165 from pure culture and food samples.

AIMS: We compared the efficiency of universal pre-enrichment broth (UPB), modified Escherichia coli broth containing novobiocin (mEC + n), modified Tryptic Soy Broth (mTSB) and mTSB with novobiocin (mTSB + n) for the enrichment of non-O157 Shiga-toxin-producing E. coli (STEC). METHODS AND RESULTS: Freeze-injured and control non-O157 STEC (O91, O103, O111, O119, O121, O145 and O165) strains were used to artificially contaminate beef and radish sprout samples, which were then cultivated in each of the four enrichment media. After incubation, STEC strains were detected by loop-mediated isothermal amplification (LAMP) and plating assays. Enrichment in mEC + n was least effective for facilitating the detection of uninjured STEC strains in radish sprouts, while mTSB + n was least effective for enriching freeze-injured non-O157 STEC strains from beef samples for detection by LAMP assay. UPB and mTSB were superior to mEC + n and mTSB + n for the enrichment of non-O157 STEC from food samples. CONCLUSIONS: The enrichment of non-O157 STEC was negatively affected by the addition of novobiocin to enrichment broths. SIGNIFICANCE AND IMPACT OF THE STUDY: Novobiocin should not be added to media used for the enrichment of non-O157 STEC in food when cell injury is anticipated.

Prevalence of early and late oral implant loss among smokers: a nationwide survey in Japan.

A cross-sectional, nationwide survey was conducted in Japan to examine the relationship between tobacco smoking and oral diseases including implant failure. A questionnaire survey was sent to designated facilities by post, and 158 answered questions regarding implant loss. Smoking status, number of implant failures, and other related variables were collected from the participating dentists as secondary data. A total of 1966 patients who were treated with dental implants by participating dentists during the survey period were analysed. Among the total sample, 90 (5%) had early implant loss (≤12 months) and 153 (8%) had late implant loss (>12 months and ≤120 months). The number of pack-years was significantly higher in the total (early and late) implant loss group (31.2±15.9) than in the group with no implant loss (26.1±18.1) (P=0.026). In the multivariate analysis, the number of implants installed, smoking, and pack-years were significant factors for total implant loss. The adjusted odds ratio for implant failure for current smokers compared with never smokers was 2.07 (95% CI 1.19-3.62) for early implant loss and 1.48 (95% CI 0.92-2.37) for late implant loss. This study reaffirms that current smoking is associated with an increased risk of early implant loss, irrespective of the duration of smoking exposure.

A rat model of human T lymphocyte virus type I (HTLV-I) infection. 1. Humoral antibody response, provirus integration, and HTLV-I-associated myelopathy/tropical spastic paraparesis-like myelopathy in seronegative HTLV-I carrier rats.

Human T lymphocyte virus type I (HTLV-I) can be transmitted into several inbred strains of newborn and adult rats by inoculating newly established HTLV-I-immortalized rat T cell lines or the human T cell line MT-2. The transmission efficiency exceeds 80%, regardless of strain differences or the age at transmission. The production of anti-HTLV-I antibodies significantly differs among the strains and depends on the age at the time of transmission. Rats neonatally inoculated with HTLV-I-positive rat or human cells generally become seronegative HTLV-I carriers throughout their lives, whereas adult rats inoculated with HTLV-I-positive cells at 16 wk of age become seropositive HTLV-I carriers. The HTLV-I provirus genome is present in almost all organs, regardless of whether the carriers are seronegative or seropositive. According to antibody titers to HTLV-I, there are three groups of inbred rat strains: ACI, F344, and SDJ (high responders); WKA, BUF, and LEJ (intermediate responders); and LEW (low responder). Three of three 16-mo-old seronegative HTLV-I carrier rats of the WKA strain developed spastic paraparesis of the hind legs. Neuropathological examinations revealed that the lesions were confined primarily to the lateral and anterior funiculi of the spinal cord. Both myelin and axons were extensively damaged in a symmetrical fashion, and infiltration with massive foamy macrophages was evident. The most severe lesions were at levels of the thoracic cord and continued from the cervical to the lumbar area. These histopathological features as well as clinical symptoms largely parallel findings in humans with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). These HTLV-I carrier rats, in particular the WKA rats described above, can serve as a useful animal model for investigating virus-host interactions in the etiopathogenesis of HTLV-I-related immunological diseases, particularly HAM/TSP.

Taxonomic revision of the genus Zygorhizidium: Zygorhizidiales and Zygophlyctidales ord. nov. (Chytridiomycetes, Chytridiomycota).

During the last decade, the classification system of chytrids has dramatically changed based on zoospore ultrastructure and molecular phylogeny. In contrast to well-studied saprotrophic chytrids, most parasitic chytrids have thus far been only morphologically described by light microscopy, hence they hold great potential for filling some of the existing gaps in the current classification of chytrids. The genus Zygorhizidium is characterized by an operculate zoosporangium and a resting spore formed as a result of sexual reproduction in which a male thallus and female thallus fuse via a conjugation tube. All described species of Zygorhizidium are parasites of algae and their taxonomic positions remain to be resolved. Here, we examined morphology, zoospore ultrastructure, host specificity, and molecular phylogeny of seven cultures of Zygorhizidium spp. Based on thallus morphology and host specificity, one culture was identified as Z. willei parasitic on zygnematophycean green algae, whereas the others were identified as parasites of diatoms, Z. asterionellae on Asterionella, Z. melosirae on Aulacoseira, and Z. planktonicum on Ulnaria (formerly Synedra). According to phylogenetic analysis, Zygorhizidium was separated into two distinct order-level novel lineages; one lineage was composed singly of Z. willei, which is the type species of the genus, and the other included the three species of diatom parasites. Zoospore ultrastructural observation revealed that the two lineages can be distinguished from each other and both possess unique characters among the known orders within the Chytridiomycetes. Based on these results, we accommodate the three diatom parasites, Z. asterionellae, Z. melosirae, and Z. planktonicum in the distinct genus Zygophlyctis, and propose two new orders: Zygorhizidiales and Zygophlyctidales.

Skew in T cell receptor usage with polyclonal expansion in lesions of oral lichen planus without hepatitis C virus infection.

Oral lichen planus (OLP) is a refractory disorder of the oral mucosa. Its predominant symptoms are pain and haphalgesia that impair the quality of life of patients. OLP develops via a T cell-mediated immune process. Here, we examined the characteristics of the infiltrating T cells in terms of the T cell receptor (TCR) repertoires, T cell clonality, T cell phenotypes and cytokine production profiles. TCR repertoire analyses and CDR3 size spectratyping were performed using peripheral blood mononuclear cells (PBMCs) and tissue specimens of OLP biopsies from 12 patients. The cytokine expression profiles and T cell phenotypes were measured by real-time quantitative polymerase chain reaction. We observed that there were skewed TCR repertoires in the tissue samples (TCRVA8-1, VA22-1, VB2-1, VB3-1 and VB5-1) and PBMCs (TCRVA8-1, VB2-1, VB3-1 and VB5-1) from OLP patients. Furthermore, the CDR3 distributions in the skewed TCR subfamilies exhibited polyclonal patterns. We observed increases in CD4(+) T lymphocytes, interleukin (IL)-5, tumour necrosis factor (TNF)-alpha and human leucocyte antigen D-related in the OLP tissue specimens. Taken together, the present results suggest that T cells bearing these TCRs are involved in the pathogenesis of OLP, and that IL-5 and TNF-alpha may participate in its inflammatory process.

Cost Analysis of Transplantation in Japan, Performed With the Use of the National Database.

BACKGROUND: When assessing the cost of transplants in Japan, earlier studies have been limited to case series that investigated inpatient cost alone. Few studies have evaluated total cost, which includes inpatient, outpatient, and pharmaceutical costs, or compared costs before and after transplantation. Using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB), we investigated the total cost of major transplantation and contributing factors. METHODS: We analyzed the cost and complications of patients who underwent a cadaveric renal transplantation (CRT), living renal transplantation (LRT), living-donor liver transplantation (LDLT), allogeneic bone marrow transplantation, autologous bone marrow transplantation, allogeneic peripheral blood stem cell transplantation, or autologous peripheral blood stem cell transplantation (auto-PBSCT) from April 2009 to March 2010. RESULTS: The highest total cost of the month of transplantation was 4.95 million yen (JPY) for LDLT. Among renal transplantations, the cost of CRT was higher than LRT (3.69 vs 3.55 million JPY). Recipients of auto-PBSCT complicated by graft-versus-host disease, urinary tract infection, sepsis, or pneumonia had a significantly higher average total cost during the month of transplantation and the 2 following months than patients without it, as well as statistically longer total treatment days. CONCLUSIONS: In Japan, almost all medical services are covered by national health insurance, and the Japan government has begun to allow the use of the NDB for research activities. This is the first study to use the NDB to analyze the cost of transplantation, with technical and institutional limitations.

Facial emphysema caused by cheek bite.

Biting of the buccal mucosa is very frequent injury, whereas facial emphysema caused by cheek bite is rare. We report a case of facial emphysema causing puffing of the cheek through a self-inflicted bite of the buccal mucosa.

Two pyridine analogues with more effective ability to reverse multidrug resistance and with lower calcium channel blocking activity than their dihydropyridine counterparts.

Four pyridine analogues and their dihydropyridine counterparts were examined for their ability to reverse drug resistance in a multidrug-resistant human carcinoma cell line, KB-C2. Two pyridine analogues were more able to reverse drug resistance than their dihydropyridine counterparts. The other two pyridine analogues had an effect on drug resistance similar to their dihydropyridine counterparts. The calcium channel-blocking activity of all the pyridine analogues was considerably lower than that of the dihydropyridine analogues. Of the pyridine analogues, 2-[4-(diphenylmethyl)-1-piperazinyl]ethyl 5-(trans-4,6-dimethyl-1,3,2-dioxaphosphorinan-2-yl)-2,6-dimethyl-4 -(3- nitrophenyl)-3-pyridinecarboxylate P-oxide (PAK-104P) was the most effective in reversing multidrug resistance. PAK-104P (1 and 5 microM) completely reversed the drug resistance in KB-8-5 and KB-C2 cells, respectively. The reversing effect of PAK-104P was greater than that of other multidrug resistance-reversing agents, cepharanthine, verapamil, nimodipine, and nicardipine. PAK-104P at 1 microM increased about 10-fold the accumulation of vinblastine in KB-C2 cells, whereas verapamil at the same concentration increased the accumulation about 2-fold. The inhibition of [3H]azidopine photolabeling of P-glycoprotein by the pyridine and dihydropyridine analogues except 2-[methyl(phenyl-methyl)amino]ethyl 4-(2-chlorophenyl)-5-(4-methyl-1,3,2-dioxaphosphorinan-2-yl)-1,4-d ihydro-2,6- dimethyl-3-pyridinecarboxylate P-oxide correlated with the reversing of drug resistance by the analogues. Some newly synthesized pyridine analogues seemed to have lower calcium channel-blocking activity and more potent resistance-reversing ability than verapamil and other calcium channel blockers.

Correlation between reversing of multidrug resistance and inhibiting of [3H]azidopine photolabeling of P-glycoprotein by newly synthesized dihydropyridine analogues in a human cell line.

Ten synthetic dihydropyridine analogues were investigated for their ability to reverse drug resistance in a multidrug-resistant human carcinoma cell line, KB-Cl. Four dihydropyridine analogues completely reversed the resistance, three lowered the resistance, and three had little effect. The radioactive photoactive dihydropyridine calcium channel blocker, [3H]azidopine, photolabels P-glycoprotein in membrane vesicles from KB-Cl cells. This photolabeling was almost completely inhibited by excess dihydropyridine analogues that reversed or lowered drug resistance. In contrast, the labeling was not significantly inhibited by analogues that do not reverse resistance. Among other reversing agents, cepharanthine and reserpine inhibited the [3H]azidopine photolabeling, but thioridazine did not. N-Solanesyl-N,N'-bis(3,4-dimethoxybenzyl)ethylenediamine slightly inhibited the labeling at 100 microM. An anticancer agent, vinblastine, also inhibited the labeling. The correlation between the reversing of the drug resistance and the inhibition of the [3H]azidopine photolabeling of P-glycoprotein by dihydropyridine analogues suggests a role for P-glycoprotein in multidrug resistance and also the reversing of the resistance by dihydropyridine analogues.

Effect of a dihydropyridine analogue, 2-[benzyl(phenyl)amino]ethyl 1,4-dihydro-2,6-dimethyl-5-(5,5-dimethyl-2-oxo- 1,3,2-dioxaphosphorinan-2-yl)-1-(2-morpholinoethyl)-4-(3-nitrophenyl)-3 -pyridinecarboxylate on reversing in vivo resistance of tumor cells to adriamycin.

A newly synthesized dihydropyridine analogue, 2-[benzyl(phenyl)-amino]ethyl 1,4-dihydro-2,6-dimethyl-5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorina n-2-yl)-1- (2-morpholinoethyl)-4-(3-nitrophenyl)-3-pyridinecarboxylate (PAK-200), at 5 microM inhibited the efflux of [3H]vincristine from KB-C2 cells and increased the accumulation of [3H]vincristine in KB-C2 cells to a level similar to that in KB-3-1 cells. PAK-200 inhibited the photoaffinity labeling of P-glycoprotein in KB-C2 membranes by [3H]azidopine. At 5 microM, PAK-200 enhanced the cytotoxic effect of Adriamycin on drug-sensitive KB-3-1 cells, multidrug-resistant KB-8-5 cells, and two human colorectal carcinoma tumor lines, COK-28LN and COK-36LN, by factors of 2, 5, 2, and 3 times, respectively. The calcium antagonistic activity of PAK-200 was about 1000 and 5 times lower than that of another dihydropyridine analogue, nicardipine, and of verapamil, respectively. PAK-200 in combination with Adriamycin completely suppressed the growth of KB-3-1 and COK-36LN and partially suppressed the growth of KB-8-5 but had no significant effect on COK-28LN cells xenografted in nude mice. The level of MDR1 expression of COK-36LN was about 3 times higher than that of COK-28LN, but lower than that of KB-8-5 cells. These results suggest that the interaction of PAK-200 with P-glycoprotein may be partly correlated with the enhancement of the antitumor effect of Adriamycin on xenografted KB-8-5 and COK-36LN cells in nude mice.

Influence of arthroscopically observed fibrous adhesions before and after joint irrigation on clinical outcome in patients with chronic closed lock of the temporomandibular joint.

The aim of this study was to investigate the changes in the state of arthroscopically observed fibrous adhesions (FA) after visually guided irrigation (VGIR) and the influence of FA on clinical outcome in patients with chronic closed lock of the temporomandibular joint (TMJ). Forty-eight TMJs of 48 patients with unilateral chronic closed lock were enrolled in this study. All 48 joints underwent VGIR twice. After the first VGIR (immediately before the second VGIR), clinical outcome was assessed as regards maximal interincisal opening (MIO) and self-evaluated TMJ pain (VAS). Thirty patients were symptom-free (good outcome group) and the remaining 18 patients had symptoms (poor outcome group). In each group, the changes of the MIO, VAS and severity of FA (FA score) after the first VGIR were studied. The influence of FA score in the first and second VGIR on clinical outcome was analyzed by logistic regression analysis. There was no joint with disappearance or reduction of FA after the first VGIR. In both groups, MIO and VAS were significantly improved after the first VGIR even though the state of FA became significantly worse. The multivariate logistic regression analysis showed that the risk of poor outcome for FA scores in the first and second VGIR were 0.89-times (95% CI: 0.33-2.40, P=0.82) and 1.76-times (95% CI: 0.54-5.73, P=0.35), respectively. The dose-response relationships between FA scores in the first or second VGIR were not significant. In conclusion, our results indicate that the presence of FA or a postoperative worsening of FA (including postoperative new FA formation) seems not to affect the clinical outcome as regards MIO and VAS in patients with chronic closed lock of the TMJ.

Vacuolation induced by cytotoxin from Helicobacter pylori is mediated by the EGF receptor in HeLa cells.

The bacterial toxin VacA produced by H. pylori induces large vacuoles in several types of cultured cells such as HeLa cells or gastric cells. To determine the mechanism of vacuolation induced by this toxin we employed several inhibitors of membrane trafficking and endocytosis. The development of vacuolation induced by VacA in HeLa cells were prevented by bafilomycin A1 and low temperature conditions that inhibited vesicle transport or endocytosis. Formation of large vacuoles was also inhibited by an antibody against EGF receptor, which was previously shown to be internalized by endocytosis, but not by an anti-transferrin receptor antibody. Moreover, proteins of 58 and 37 kDa, corresponding to fragments of VacA, were recognized by an anti-H. pylori antibody after immunoprecipitation with anti-EGF receptor of cell extracts from HeLa cells treated with VacA, but not from untreated HeLa cells. We suggest that VacA may enter cells by endocytosis mediated by the EGF receptor. These are the first data indicating that the EGF receptor may be significant in the development of vacuolation caused by VacA.

Helicobacter pylori-associated gastric pro- and antioxidant formation in Mongolian gerbils.

Helicobacter pylori colonized gastric mucosa is manifest in a significant neutrophil infiltration with an extensive level of oxyradical formation. Mongolian gerbil is one of the excellent models for H. pylori-infection. The present study was designed to investigate pro- and antioxidant formation in the stomach of H. pylori-positive gerbils. Fourteen male Mongolian gerbils (MGS/Sea) were orally inoculated with H. pylori (ATCC43504) (Hp group) and 15 gerbils were inoculated with the culture media (Control). H. pylori infection was confirmed by the serum anti-H. pylori IgG test. Each gerbil was evaluated 6 or 12 weeks after the inoculation. Neutrophil infiltration was assessed by the tissue MPO activity. Mucosal oxidative stress was evaluated by thiobarbituric acid-reactive substances (TBARS), total glutathione contents, glutathione peroxidase (GSHPx) activity and Cu-, Zn-superoxide dismutase (SOD) activity. In Hp group, the H. pylori was persistently infected until 12 weeks. The level of MPO activity was significantly higher in Hp group at 6 and 12 weeks. Although the levels of TBARS and total glutathione were within the same range as controls at 6 weeks, they were significantly increased at 12 weeks. However, GSHPx activity was significantly increased at 6 weeks, but became the same range with the controls at 12 weeks. SOD activity showed no significant increase in Hp group at 6 and 12 weeks. In conclusion, H. pylori inoculation induced gastric mucosal neutrophil activation and pro-oxidant formation and also increased total glutathione contents, one of the mucosal antioxidants in gerbils.

Long-term assessment of posttransplant renal prognosis with 31 P magnetic resonance spectroscopy.

BACKGROUND: 31P-magnetic resonance spectroscopy (MRS) has been widely used to study pretransplantation renal viability, and although some had discussed posttransplant renal viability, no one has examined long-term posttransplant renal prognosis. We discuss the use of 31P-MRS to assess the long-term prognosis from the time when MRS was performed. METHODS: We studied 20 patients with renal allografts. 1.5 Tesla clinical magnetic resonance imaging (MRI) and 15 cm surface coil was used for 31P-MRS. Localized 31P-MRS was done using image selected in vivo spectroscopy (ISIS) method. Individual peaks were fitted by Lorenzian line-shapes with a least square method and peak area ratios were calculated. RESULTS: A beta-adenosine triphosphate/inorganic phosphate (beta-ATP/Pi) ratio >1.2 had sensitivity of 92.8%, specificity of 100%, and accuracy of 95% for predicting 3-year renal survival; a beta-ATP/Pi ratio >1.2 had sensitivity of 90.9%, specificity of 66.7%, and accuracy of 76.9% for predicting 5-year renal survival. We compared 31P-MRS spectra data between the survived group and failed group. The survived group had significantly higher beta-ATP/Pi, alpha-ATP/Pi, and phosphodiester (PDE)/Pi ratios than the failed group. CONCLUSIONS: We discussed the beta-ATP/Pi value as a parameter for predicting long-term survival of a transplanted kidney from the time when MRS was performed. A value above 1.2 suggests a high probability of 3-year renal survival, whereas a value over 2.5 indicates that the transplanted kidney could survive over 5 years. 31P-MRS may be useful for predicting long-term survival of transplanted kidneys, but additional studies are needed.

Cholecystokinin: critical role in mediating olfactory influences on reproduction.

Our electrophysiological studies in female mice have demonstrated that electrical stimulation of the accessory olfactory bulb excites tuberoinfundibular dopaminergic arcuate neurons via the amygdala-stria terminalis route. This study shows that the medial preoptic area is identified as an additional relay for the excitatory transmission by examining the effectiveness of locally infused lignocaine anaesthetic in blocking the transmission and that of electrical stimulation in evoking a shorter latency response. Based on the known immunohistochemical findings, further attention is focused on a transmitter mediating synaptic transmission in the medial preoptic area. The cholecystokinin-B type receptor antagonist L-365,260 (0.3, 0.6, 0.9 pmol), but not the A type receptor antagonist L-364,718 (0.9 pmol), infused into the medial preoptic area, blocked the excitation of tuberoinfundibular arcuate neurons in a dose-dependent manner. Conversely, cholecystokinin octapeptide (0.6 pmol) increased firing activity in such neurons. The antagonizing effect of L-365,260 was reproduced in the context of the olfactory block to pregnancy: bilateral infusions of this drug into the medical preoptic area of recently mated females immediately before exposures to strange males' pheromones prevented them from inducing pregnancy block. These findings implicate cholecystokinin acting on cholecystokinin-B receptors in the medial preoptic area as a mediator of olfactory influences on reproductive physiology.

Excitatory influence of the accessory olfactory bulb on tuberoinfundibular arcuate neurons of female mice and its modulation by oestrogen.

The role of the accessory olfactory bulb in conveying pheromonal information to tuberoinfundibular arcuate neurons was examined electrophysiologically in chloral hydrate-anaesthetized, oestrogen (0.5 micrograms in silastic capsules)-treated and untreated ovariectomized Balb/c female mice. Electrical stimulation of the accessory olfactory bulb orthodromically excited part of tuberoinfundibular neurons which were antidromically stimulated from the median eminence and histologically verified as being located within the arcuate nucleus. No inhibitions followed accessory bulb stimulation. The excitatory response to accessory bulb stimulation was reversibly blocked by the local anaesthetic lignocaine infused into the amygdala. The percentage of tuberoinfundibular arcuate neurons responding to accessory bulb stimulation was significantly higher in oestrogen-treated than in untreated animals. There was no difference between the two groups for the antidromic activation threshold, spontaneous firing rate, absolute refractory period or frequency of successful antidromic propagation into the soma of tuberoinfundibular arcuate neurons. In oestrogen-treated preparations, tuberoinfundibular arcuate neurons responsive and unresponsive to accessory bulb stimulation could be distinguished by the frequency of successful antidromic propagation into the soma. These studies demonstrate that olfactory relay neurons in the accessory olfactory bulb act to enhance the activity of a subpopulation of tuberoinfundibular arcuate neurons via the amygdala and that this neural transmission is modulated by oestrogen.

Neural mechanisms underlying the action of primer pheromones in mice.

Our electrophysiological experiments in female mice have provided evidence that electrical stimulation of the accessory olfactory bulb orthodromically excites a subpopulation of tuberoinfundibular arcuate neurons by way of the amygdala. The present study shows that half of such neurons are identified as dopaminergic by examining the effectiveness of infusing 6-hydroxydopamine and 5,7-dihydroxytryptamine locally into the median eminence in blocking their antidromic response. Further attention is focused on excitatory amino acid receptors within the amygdala and the amygdaloid pathway that mediate the accessory bulb-induced excitation of tuberoinfundibular arcuate neurons. The excitatory transmission was reversibly blocked by intra-amygdala infusion (3 nmol) of the excitatory amino acid antagonists kynurenic acid, D,L-2-amino-5-phosphonovalerate, gamma-D-glutamylaminomethylsulphonate and D,L-2-amino-4-phosphonobutyrate. Intra-amygdala infusions (3 nmol) of N-methyl-D-aspartate and kainate markedly enhanced the firing activity of tuberoinfundibular arcuate neurons with excitatory inputs from the accessory bulb, whereas similar infusions of quisqualate were without effect Intra-stria terminalis infusions of the local anaesthetic lignocaine completely abolished the excitatory transmission in all the cells tested. Furthermore, tuberoinfundibular arcuate neurons stimulated from the accessory bulb were also orthodromically stimulated from the stria terminalis with a shorter latency. These studies demonstrate that the projections of the accessory olfactory bulb activate excitatory amino acid receptors within the amygdala and subsequently the stria terminalis route, thereby causing excitation of tuberoinfundibular dopaminergic arcuate neurons. This functional pathway can account for the reproductive effects so far described as a consequence of vomeronasal chemoreception.

The action of oxytocin originating in the hypothalamic paraventricular nucleus on mitral and granule cells in the rat main olfactory bulb.

The effects of electrical stimulation of the hypothalamus paraventricular nucleus on the spontaneous firing of mitral and granule cells in the main olfactory bulb were examined in ovariectomized female rats under urethane anaesthesia. High-frequency stimulation (0.5-1.0 mA, 10-20 pulses at 100 Hz) of the paraventricular nucleus produced inhibitory responses in 80% of mitral cells tested and excitatory responses in 74% of granule cells tested, with latencies ranging from 2 to 150 s. Both responses were blocked by infusions into the olfactory bulb of [d(CH2)5, Tyr(Me)2]ornithine-vasotocin (10 pmol), an oxytocin antagonist, and mimicked by intracerebroventricular infusions (0.2 or 0.4 nmol) or microiontophoretic applications of oxytocin but not by intracerebroventricular infusions of vasopressin (1 or 2 nmol). Infusions of 0.5% lignocaine, a local anaesthetic, into either the medial olfactory tract or the medial forebrain bundle failed to block the responses of mitral and granule cells to the stimulation. Unilateral transections at various levels between the bulb and the paraventricular nucleus also failed to block the responses. There were cases in which significant responses of mitral and granule cells to the stimulation required 60 or more pulses after the lignocaine infusions or transections, however. These results suggest that oxytocin originating in the hypothalamic paraventricular nucleus reaches the olfactory bulb following its release partly into the cerebrospinal fluid and acts to decrease olfactory processing.