Demonstration of Single-Barium-Ion Sensitivity for Neutrinoless Double-Beta Decay Using Single-Molecule Fluorescence Imaging.

A new method to tag the barium daughter in the double-beta decay of ^{136}Xe is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba^{++}) resolution at a transparent scanning surface is demonstrated. A single-step photobleach confirms the single ion interpretation. Individual ions are localized with superresolution (∼2 nm), and detected with a statistical significance of 12.9σ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double-beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.

Demonstration of event position reconstruction based on diffusion in the NEXT-white detector.

Noble element time projection chambers are a leading technology for rare event detection in physics, such as for dark matter and neutrinoless double beta decay searches. Time projection chambers typically assign event position in the drift direction using the relative timing of prompt scintillation and delayed charge collection signals, allowing for reconstruction of an absolute position in the drift direction. In this paper, alternate methods for assigning event drift distance via quantification of electron diffusion in a pure high pressure xenon gas time projection chamber are explored. Data from the NEXT-White detector demonstrate the ability to achieve good position assignment accuracy for both high- and low-energy events. Using point-like energy deposits from 83mKr calibration electron captures (E∼45 keV), the position of origin of low-energy events is determined to 2 cm precision with bias <1mm. A convolutional neural network approach is then used to quantify diffusion for longer tracks (E≥1.5 MeV), from radiogenic electrons, yielding a precision of 3 cm on the event barycenter. The precision achieved with these methods indicates the feasibility energy calibrations of better than 1% FWHM at Qßß in pure xenon, as well as the potential for event fiducialization in large future detectors using an alternate method that does not rely on primary scintillation.

Effect of breed body-size on leptin amniotic fluid concentrations at term pregnancy in dogs.

Because of the need to improve the knowledge about canine perinatology, and given the major role of fetal fluids in sustaining the course of pregnancy and fetal development, an in-depth analysis to better understand the role of some hormones in these compartments is essential. Among all, leptin is recognized to play a key role not only on the energetic homeostasis, but also at multiple levels, influencing the control of reproduction, food assumption and metabolism. Even if in humans and other species it is reported the presence of leptin receptors during fetal development, very little is known about the canine species, in which the role of leptin still needs to be fully understood. The present study aimed to assess the amniotic fluid leptin (AFL) concentrations at term pregnancy in healthy dogs, and to evaluate the possible influence played by breed body-size (after assessment of correlation with maternal bodyweight and placental weight), or other maternal (age, parity, and the so-called "litter effect") and neonatal (gender, birth weight, litter size) parameters on AFL concentrations, analyzed by ELISA test. The study was performed on 90 healthy, viable and normal weighted puppies, 39 small-sized (adult body weight < 10 kg) and 51 large-sized (adult body weight > 25 kg), born by 29 purebred, healthy bitches, submitted to elective Caesarean section because of breed-related or individual high risk for dystocia. The results showed that the mean AFL concentration in the small-sized puppies was significantly (p < 0.05) higher in comparison to large-sized puppies (867.48 vs 698.42 pg/ml), while all the other studied parameters did not show to influence AFL concentrations. In conclusions, the present study showed significant higher at term AFL concentrations in small-sized as compared to large-sized breeds, suggesting an influence of breed body-size on fetal metabolism, as previously reported for NEFA and IGF-I.

Plasma and synovial fluid concentrations of nimesulide and its main metabolite after a single or repeated oral administration in patients with knee osteoarthritis.

The aim of this study was to evaluate plasma and synovial fluid concentrations of the non-steroidal anti-inflammatory drug nimesulide and its major metabolite (hydroxynimesulide, M1), after a single 100 mg dose of nimesulide and a repeated (14 day) administration, 100 mg twice a day, in patients with osteoarthritis of the knee and joint effusion. Nimesulide was rapidly absorbed in plasma and distributed in synovial fluid. On day 1, effective concentrations were present 30 min after the first dose and on day 14, the synovial fluid concentration of nimesulide was significantly higher than that measured on day 1; no accumulation was observed in plasma. After 14 days of treatment, both the plasma and synovial fluid concentrations of M1 were significantly higher than those measured on day 1. These data may help to explain the rapid onset of the analgesic effect of nimesulide demonstrated in several clinical conditions, including painful osteoarthritis.

Neurotransmitter amino acid variations in striatum of rats exposed to 50 Hz electric fields.

Concentration of neurotransmitter amino acids (Tau, Gly, Asp, Glu, Gln, Ala, GABA) were measured in rat striatum following varying exposure (320 to 1408 h) to high intensity (50 Hz) electric fields. Tissue extracts in methanol, after drying, were derivatized with dansyl chloride and the amino acids quantitated by high-pressure liquid chromatography with ultraviolet detection. Short exposures (320 h) to 100 kV/m field induced a decrease in almost all tested amino acids. Longer exposure times (640 h) to 25 and 100 kV/m were only associated with a decrease in Tau. A further increase of the exposure time (1240 and 1408 h) both at 25 and 180 kV/m were mainly associated with a reduction of the amino acid levels. It is concluded that electric fields in the range 20-180 kV/m generate bimodal variations in neurotransmitter amino acids with troughs at very short and longer exposure times, independent from the field strength.

Interleukin-6 affects scopolamine-induced amnesia, but not brain amino acid levels in mice.

We have previously shown that, after peripheral administration, different cytokines affect cognitive functions in mice. In this study, we evaluated the effects of mouse interleukin-6 (IL-6) on the classical behavioural test of scopolamine-induced amnesia for a passive avoidance response in the mouse. Pretraining i.p. administration of this cytokine (0.125 and 0.5 microgram/mouse) significantly reduced the amnesic action of the muscarinic receptor antagonist. As it is well known that brain amino acids are deeply involved in the modulation of cognitive processes we measured the levels of glutamine, aspartic acid, glutamic acid and GABA in the hippocampus and hypothalamus of mice treated with IL-6. At both doses which affected the cognitive functions, this cytokine had no effect on brain levels of measured amino acids. Neither nociceptive thresholds to a thermal stimulus, nor spontaneous locomotor activity were modified by the acute administration of IL-6 (0.5 microgram/mouse). Our data confirm previous observations indicating that peripheral administration of cytokines affects some, but not other brain functions and suggest the involvement of IL-6 in the central modifications induced by the immune activation.

Effects of interleukin-1 beta and interleukin-2 on amino acids levels in mouse cortex and hippocampus.

We measured the levels of glutamine, aspartic acid, glutamic acid and GABA in cortex and hippocampus of mice acutely treated with i.p. human recombinant interleukin-2 (IL-2) or human recombinant interleukin-1 beta (IL-1 beta). Administration of IL-2 (5.0 micrograms kg-1) induced a slight but statistically significant increase in glutamine concentrations in both brain areas, while similar administration of IL-1 beta (20 micrograms kg-1) significantly reduced the hippocampal levels of glutamine, glutamic acid and GABA. Our data suggest that brain amino acid pathways are involved in the central modifications induced by IL-1 beta.

GM-CSF affects hypothalamic neurotransmitter levels in mice: involvement of interleukin-1.

We studied the effects of granulocyte-macrophage colony stimulating factor (GM-CSF) on the brain levels of several neurotransmitters in mice. Administration of GM-CSF (5.0 and 10 microg, i.p.) significantly reduced the hypothalamic levels of glutamine, glutamic acid, GABA and aspartic acid. GM-CSF (5.0 microg, i.p.) also induced a significant reduction of norepinephrine and serotonin levels in the hypothalamus, without affecting dopamine levels. The hippocampal levels of neurotransmitters were not modified by GM-CSF administration. The peripheral administration of a specific interleukin-1 receptor antagonist (IL-1ra, 50 microg, i.p.) blocked the effects of GM-CSF. These results confirm our previous behavioural data suggesting that GM-CSF is able to exert neuromodulatory actions.

Neurochemical changes of long-term adrenalectomy in rat brain: effects on neurotransmitter amino acids.

The levels of five amino acids together with glutamine synthetase activity, were measured in brain regions of rats with bilateral adrenalectomy, performed in newly weaning rats on postnatal day 22 and sacrificed 3 months later. Adrenalectomy caused a general decrease of glutamine concentration in three hippocampal regions (CA1-CA2, CA3, CA4-dentate gyrus), in hypothalamus, striatum and cerebellum. This reduction, which was particularly significant in hippocampus and cerebellum, was paralleled by a decrease of glutamine synthetase activity. Treatment with corticosterone reversed the effect of adrenalectomy. Little or no change was observed in the tissue levels of taurine, aspartic, glutamic or gamma-amino butyric acids.

Effects of diazepam on nociception in rats.

Acute i.p. injection of diazepam (1 mg/kg) resulted in a moderate increase in the tail-flick latency in rats. Tolerance to this diazepam effect developed after 10 days of diazepam treatment (1 mg kg-1 day-1). The benzodiazepine antagonist Ro 15-3505 only partially reversed the effect of diazepam on nociception. Naloxone (5 mg/kg i.p.) failed to affect the effect of diazepam on nociception, while the kappa antagonist MR 2266 fully antagonized the diazepam-induced increase of the tail-flick latency. Diazepam injected intracerebroventricularly (1, 5, 20 micrograms/rat) did not alter basal nociceptive threshold, however, diazepam injected intrathecally (20 micrograms/rat) prolonged the tail-flick latency. Furthermore, intracerebroventricular injection of muscimol partially antagonized the i.p. diazepam-induced increase of the tail-flick latency. These results suggest that benzodiazepine receptor sites are partially involved in the effect of diazepam on nociception and indicate that an indirect kappa-opioid-receptor-mediated mechanism may be involved. The anatomical site of diazepam action on tail-flick latency seems to be at the spinal level. Descending axons to the spinal cord from brain areas reached by intracerebroventricular injection of muscimol seem to modulate the effect of diazepam effect on nociception.

Reversal of the effect of centrally-administered diazepam on morphine antinociception by specific (Ro 15-1788 and Ro 15-3505) and non-specific (bicuculline and caffeine) benzodiazepine antagonists.

Diazepam, injected into the lateral ventricles reduced the antinociceptive effect of morphine in rats, as measured by the tail-flick method. Specific antagonists of diazepam (Ro 15-1788 and Ro 15-3505) had no effect themselves but prevented inhibition by diazepam of morphine antinociception. Furthermore, the action of diazepam was partially reversed by intracerebroventricular injection of bicuculline or caffeine. These findings support the view that the depressant effect of diazepam on morphine antinociception is specific and GABAergic in nature and that some actions of diazepam are also mediated via the purinergic system.

Zopiclone potentiates the antinociceptive effect of morphine in rats.

The antinociceptive effect of morphine, as determined by the tail-flick test, was dose-dependently increased by the intraperitoneal injection of zopiclone. The benzodiazepine antagonists Ro 15-1788 (flumazepil) and Ro 15-3505, when intraperitoneally injected, significantly antagonized the effect of intraperitoneal injection of zopiclone on morphine antinociception. Intrathecal injection of zopiclone potentiated morphine antinociception, while the intracerebroventricular injection of zopiclone failed to enhance morphine antinociception and the intracerebroventricular injection of flumazepil to antagonize the intraperitoneal-zopiclone-induced increase in morphine antinociception. These results suggest that benzodiazepine sites are specifically involved in the potentiating effect of zopiclone on morphine antinociception. The anatomical locations of the receptors involved seem to be at the spinal level.

Modification of GABA turnover in the striatum and hippocampus of the rat after zopiclone.

The effects of zopiclone, a non-benzodiazepine compound that interacts with benzodiazepine receptors, on GABA turnover rate and GABA content in the rat striatum and hippocampus have been studied. Intraperitoneal administration of zopiclone reduced the GABA turnover rates in both the striatum and hippocampus, as estimated from the rate of GABA accumulation after inhibition of GABA transaminase by aminooxyacetic acid (AOAA). The effect of zopiclone on AOAA-induced accumulation of GABA in the hippocampus and striatum was blocked by the intraperitoneal injection of the benzodiazepine receptor antagonist Ro 15-3505. Furthermore, zopiclone slightly but significantly decreased GABA content in the hippocampus, the decrease being blocked by coadministration of the benzodiazepine receptor antagonist Ro 15-1788. Our results confirm that the GABAergic system plays a role in the mechanism of action of zopiclone.

Effects of tramadol on synovial fluid concentrations of substance P and interleukin-6 in patients with knee osteoarthritis: comparison with paracetamol.

Both the analgesic drugs tramadol and paracetamol are widely used for the symptomatic therapy of osteoarthritis (OA). The aim of this double-blind, randomised study in patients with knee OA was to compare their effects on synovial fluid concentrations of interleukin (IL)-6 and substance P (SP). Moreover, we evaluated plasma and synovial fluid concentrations of tramadol and its active metabolite (O-desmethyl-tramadol, M1) after oral treatment with this drug. Twenty patients were enrolled. A group of 10 patients received tramadol (50 mg three times a day), and another group of 10 patients were treated with paracetamol (500 mg three times a day) for 7 days. Both drugs significantly reduced the intensity of joint pain. The synovial fluid concentrations of SP were significantly reduced only by the treatment with tramadol. In this group of patients, IL-6 synovial fluid concentrations were slightly, but not significantly, decreased. Paracetamol did not significantly change the synovial fluid concentrations of SP and IL-6. After oral administration, a considerable amount of tramadol was measurable in synovial fluid. Both in plasma and synovial fluid the concentrations of M1 were markedly lower than those of tramadol, with a T/M1 ratio of 14.7+/-4.6 and 9.3+/-3.9, respectively. These data demonstrate that the activity of tramadol may involve the modulation of inflammatory mediators. Moreover, they indicate that after oral treatment with tramadol, both the parent drug and its active metabolite can penetrate into synovial fluid.

Analysis of pirprofen in cerebrospinal fluid, plasma, and synovial fluid by high-performance liquid chromatography with electrochemical detection.

We describe a high-performance liquid chromatographic method, using electrochemical detection, for the determination of pirprofen in cerebrospinal fluid (CSF), plasma, and synovial fluid (SF). A C-18 column with a mobile phase containing acetonitrile acetate:phosphate buffer (pH 3.0) was employed. Samples were added with phosphoric acid, then extracted into dichloromethane, evaporated, and injected into the chromatograph. A detection potential of +0.85 V was applied on the basis of current-potential curves. Good linearity was found for each fluid in the expected range of therapeutic concentrations. The detection limit was 0.1 ng/mL for CSF, and 1 ng/mL for plasma and SF, with a recovery greater than 96% and intraday coefficient of variation less than 5% in all cases. The main advantages of this method include high specificity and sensitivity which allow the analysis of CSF and the use of small volumes of plasma and SF. The application of the method for the analysis of plasma and SF samples and the kinetic profile in CSF are shown.

Susceptibility to seizures produced by chemical convulsants and maximal electric shock in rats after electrolytic lesions into the red nucleus.

Bilateral electrolytic lesions into the red nucleus (RN) of rat elicit an increase in susceptibility to seizures induced by pilocarpine, kainic acid, isoniazid, pentylenetetrazole, bicuculline and maximal electric shock (MES). It was also observed that carbachol-induced wet-dog shakes were increased in the RN-lesioned rats. The brain acetylcholine (ACh) and gamma-aminobutyric acid (GABA) concentrations were significantly decreased in the striatum and substantia nigra, respectively. There were no changes in electroencephalogram (EEG) recordings in the RN-lesioned group compared with sham-operated rats. Based on the results it is proposed that the RN is involved in the generalization and acceleration of seizure activity through the cholinergic and GABA-ergic system.