Effect of tryptophan depletion on symptoms of motion sickness in migraineurs.

Seven hours after 39 migraineurs and 37 controls consumed an amino acid drink that contained or omitted l-tryptophan (thereby reducing brain serotonin synthesis), motion sickness was provoked by the visual illusion of movement. Tryptophan depletion boosted dizziness, nausea, and the illusion of movement in controls to levels that approached those of migraineurs. Thus, reduced brain serotonin activity may promote vestibuloocular disturbances during motion sickness and attacks of migraine.

Triggers of motion sickness in migraine sufferers.

Objective: To determine whether susceptibility to motion sickness provoked by unexpected movement is associated with susceptibility to visually induced motion sickness in migraine sufferers.

Background: Migraine sufferers are unusually susceptible to motion sickness, but the mechanism of this susceptibility is not well understood. Possibilities include vestibular dysfunction secondary to vasomotor disturbances during migraine attacks, hyperexcitability of brainstem circuits that produce symptoms of motion sickness and migraine, and heightened susceptibility to visual illusions of movement.

The effect of glucose and mental stress on cutaneous microvascular endothelial function.

Glucose and mental stress, independently, have been found to impair arterial endothelial function (an indicator of vascular health). The present study sought to determine whether the combination of glucose and stress would have a greater effect on microvascular endothelial function than each on its own. To assess endothelial function, surges in skin blood flow (reactive hyperemia), following the release of cuff pressure to the upper arm at 200 mmHg for 5 min, were measured with laser Doppler flowmetry in 40 young, healthy females.

Signature of Mott-insulator transition with ultracold fermions in a one-dimensional optical lattice.

Using the exact Bethe ansatz solution of the Hubbard model and Luttinger liquid theory, we investigate the density profiles and collective modes of one-dimensional ultracold fermions confined in an optical lattice with a harmonic trapping potential. We determine a generic phase diagram in terms of a characteristic filling factor and a dimensionless coupling constant. The collective oscillations of the atomic mass density, a technique that is commonly used in experiments, provide a signature of the quantum phase transition from the metallic phase to the Mott-insulator phase.

Time-reversal test for stochastic quantum dynamics.

The calculation of quantum dynamics is currently a central issue in theoretical physics, with diverse applications ranging from ultracold atomic Bose-Einstein condensates to condensed matter, biology, and even astrophysics. Here we demonstrate a conceptually simple method of determining the regime of validity of stochastic simulations of unitary quantum dynamics by employing a time-reversal test. We apply this test to a simulation of the evolution of a quantum anharmonic oscillator with up to 6.

Involvement of the sympathetic nervous system in complex regional pain syndrome.

Complex regional pain syndrome (CRPS) occasionally develops as a complication of limb trauma. Sympathetic neurotransmitter release is compromised in the affected limb of at least a subgroup of patients throughout the course of the disorder, whereas signs of sympathetic deficit (a warm flushed limb) often evolve into signs of sympathetic overactivity (a cool moist limb) due to the development of adrenergic supersensitivity. Cross-talk between sympathetic neurotransmitters and the sensory neurons that signal pain appears to contribute to CRPS in a subgroup of patients.

Gaussian quantum Monte Carlo methods for fermions and bosons.

We introduce a new class of quantum Monte Carlo methods, based on a Gaussian quantum operator representation of fermionic states. The methods enable first-principles dynamical or equilibrium calculations in many-body Fermi systems, and, combined with the existing Gaussian representation for bosons, provide a unified method of simulating Bose-Fermi systems. As an application relevant to the Fermi sign problem, we calculate finite-temperature properties of the two dimensional Hubbard model and the dynamics in a simple model of coherent molecular dissociation.

Painful stimulation of the temple during optokinetic stimulation triggers migraine-like attacks in migraine sufferers.

To determine whether motion sickness induced by optokinetic stimulation would trigger migraine-like attacks, 27 migraine sufferers and 23 controls attended the laboratory up to three times at intervals of at least 3 weeks. On one occasion subjects experienced up to 15 min of optokinetic stimulation, followed by three 30-s applications of ice to the temple at 4-min intervals. On another occasion, the ice applications preceded and accompanied optokinetic stimulation.

Radiofrequency heating of painful annular disruptions: one-year outcomes.

Objective: Although several studies have reported on outcomes following heating of annular tears with a thermoresistive catheter (SpineCATH), no data are available on the efficacy of thermal treatment with a flexible radiofrequency electrode (discTRODE). A prospective case-control study was conducted to determine the efficacy of radiofrequency heating of painful annular tears in the lumbar spine.

Methods: After at least 6 months of conservative treatment, 46 patients were studied for the presence of single-level painful annular tears with magnetic resonance imaging and provocative discography.

Painful stimulation of the temple induces nausea, headache and extracranial vasodilation in migraine sufferers.

To determine whether painful stimulation of the temple would induce nausea, ice was applied to the temple for 30 s, three times at 4-min intervals in 23 migraine sufferers and 22 age- and sex-matched controls. On one occasion, the ice was applied in the presence of residual motion sickness induced by optokinetic stimulation. On another occasion, the ice application was not preceded by optokinetic stimulation (the baseline condition).

Sympathetic nervous system involvement in the syndrome of painful legs and moving toes.

The objective of this study is to investigate sympathetic nervous system involvement in 2 patients with painful legs and moving toes. The first case was studied several years after the initiating trauma produced a peripheral nerve lesion and demonstrated the characteristic sequence of progression of pain and moving toes from the injured leg to the contralateral leg. The second case was initially studied within 3 months of an injury that did not produce definitive signs of a peripheral nerve lesion.

A study in relation to the random distribution of four fibre types on clothing (incorporating a review of previous target fibre studies).

A new target fibre study was undertaken building upon eight previous published studies, which are reviewed here. Fifty-eight items of outer clothing, obtained from households across England, were taped and searched for three types of commonly occurring fibres and one less common fibre type. The tapes were examined using a combination of automatic and manual searching.

The effect of cutaneous mast cell degranulation on sensitivity to heat.

Objective: To determine whether depletion of inflammatory mediators from cutaneous mast cells influences cutaneous sensitivity to heat or the thermal hyperalgesia provoked by capsaicin or noradrenaline.

Subjects: Ten healthy men.

Methods And Results: Compound 48/80 was introduced by iontophoresis into the forearm.

A comparative evaluation of community treatments for post-partum depression: implications for treatment and management practices.

Objective: To compare existing community treatments for post-partum depression (PPD), treatment efficacy was evaluated for 146 women seeking treatment for PPD in the local community.

Methods: Self-report questionnaires were designed to assess clinical depression and anxiety (psychological and physiological), risk factors, treatment satisfaction and the impact of social supports.

Results: Comparison of treated subjects with those on a wait-list demonstrated that depression and the psychological component of anxiety decreased significantly after treatment.

Staring at one side of the face increases blood flow on that side of the face.

To investigate the effect of observation on blushing, an experimenter sat next to 28 participants and looked closely at one cheek while the participant sang (embarrassing) or read aloud (not embarrassing). Increases in cheek temperature were greater on the observed than the unobserved side during both tasks. Changes in cheek temperature were symmetrical when the experimenter sat next to another 23 participants and looked straight ahead, as well as when the experimenter stared at one side of the participant's face through a glass window while the participant sang.

Canonical Bose gas simulations with stochastic gauges.

A technique to simulate the grand canonical ensembles of interacting Bose gases is presented. Results are generated for many temperatures by averaging over energy-weighted stochastic paths, each corresponding to a solution of coupled Gross-Pitaevskii equations with phase noise. The stochastic gauge method used relies on an off-diagonal coherent-state expansion, thus taking into account all quantum correlations.

Facial pain increases nausea and headache during motion sickness in migraine sufferers.

The aim of this study was to determine whether trigeminal nerve discharge associated with painful stimulation of the temple would intensify symptoms of motion sickness in migraine sufferers. If so, this would support the notion that symptoms such as nausea and headache interact with each other during attacks of migraine. Symptoms of motion sickness were rated at 2 min intervals during 15 min of optokinetic stimulation in 27 migraine sufferers and 23 age- and sex-matched controls.

Persistence of pain induced by startle and forehead cooling after sympathetic blockade in patients with complex regional pain syndrome.

Background: Stimuli arousing sympathetic activity can increase ratings of clinical pain in patients with complex regional pain syndrome (CRPS).

Objective: To determine whether the increase in pain is mediated by peripheral sympathetic activity.

Methods: The effect of sympathetic ganglion blockade on pain evoked by a startle stimulus and cooling the forehead was investigated in 36 CRPS patients.

Suppression of pain and the R2 component of the blink reflex during optokinetic stimulation.

The effect of exposure to a rotating optokinetic drum on the electrically evoked blink reflex was investigated in 20 healthy volunteers. Pain ratings and the area under the curve of the R2 component of the blink reflex to innocuous and nociceptive trigeminal stimulation decreased substantially during and after optokinetic stimulation. At low shock intensities, R2 decreased most during optokinetic stimulation in subjects who did not develop symptoms of motion sickness.

The effect of pain on changes in heart rate during the Valsalva manoeuvre.

The presence of pain may influence autonomic function in patients with painful neurological or cardiovascular disorders. The aim of the present study was to determine whether pain influences cardiac baroreflexes during the Valsalva manoeuvre. Eighteen healthy subjects immersed their hand twice at each temperature in 30 degrees C water and painfully hot (47 degrees C) and cold water (12 degrees C and 7 degrees C) for 2.

Transcutaneous iontophoresis of methadone provokes local flushing and thermal hyperalgesia.

Objective: To investigate whether the introduction of methadone into the skin of the human forearm produces wheals, cutaneous vasodilatation or thermal hyperalgesia and, if so, to determine whether these responses are mediated by opioid receptors.

Subjects: Healthy adults.

Methods And Results: In Experiment 1 (N = 11), the increase in local blood flow (monitored with a laser Doppler flowmeter) was greater after the iontophoresis of methadone than saline (mean increase +/- S.

The effect of trigeminal nociceptive stimulation on blink reflexes and pain evoked by stimulation of the supraorbital nerve.

The aim of this study was to investigate the effect of painful conditioning stimuli on pain and blink reflexes to supraorbital nerve stimulation. Electromyograph activity was recorded bilaterally from the orbicularis oculi muscles in 13 normal participants in response to low (2.3 mA) and high-intensity (18.

Pair correlations in a finite-temperature 1D Bose gas.

We calculate the two-particle local correlation for an interacting 1D Bose gas at finite temperature and classify various physical regimes. We present the exact numerical solution by using the Yang-Yang equations and Hellmann-Feynman theorem and develop analytical approaches. Our results draw prospects for identifying the regimes of coherent output of an atom laser, and of finite-temperature "fermionization" through the measurement of the rates of two-body inelastic processes, such as photoassociation.