Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Flare

  • acute flare
  • alt flare
  • disease flare
  • severe flare
  • sle flare
  • solar flare
  • x-ray flare

  • Terms modified by Flare

  • flare reaction
  • flare response

  • Selected Abstracts

    A New X-Ray Flare from the Galactic Nucleus Detected with XMM-Newton

    A. Goldwurm
    Abstract The compact radio source Sgr A*, believed to be the counterpart of the massive black hole at the Galactic nucleus, was observed to undergo rapid and intense flaring activity in X-rays with Chandra in October 2000. We report here the detection with XMM-Newton EPIC cameras of the early phase of a similar X-ray flare from this source, which occurred on 2001 September 4. The source 2,10 keV luminosity increased by a factor ,20 to reach a level of 4 1034 erg s,1 in a time interval of about 900 s, just before the end of the observation. The data indicate that the source spectrum was hard during the flare and can be described by simple power law of slope ,0.7. This XMM-Newton observation confirms the results obtained by Chandra, suggests that, in Sgr A* , rapid and intense X-ray flaring is not a rare event and therefore sets some constraints on the emission mechanism models proposed for this source. [source]

    Tea tree oil reduces histamine-induced skin inflammation

    K.J. Koh
    Summary Background Tea tree oil is the essential oil steam-distilled from Melaleuca alternifolia , an Australian native plant. In recent years it has become increasingly popular as an antimicrobial for the treatment of conditions such as tinea pedis and acne. Objectives ,To investigate the anti-inflammatory properties of tea tree oil on histamine-induced weal and flare. Methods Twenty-seven volunteers were injected intradermally in each forearm (study and control assigned on an alternating basis) with histamine diphosphate (5 µg in 50 µL). Flare and weal diameters and double skin thickness were measured every 10 min for 1 h to calculate flare area and weal volume. At 20 min, 25 µL of 100% tea tree oil was applied topically to the study forearm of 21 volunteers. For six volunteers, 25 µL paraffin oil was applied instead of tea tree oil. Results Application of liquid paraffin had no significant effect on histamine-induced weal and flare. There was also no difference in mean flare area between control arms and those on which tea tree oil was applied. However, mean weal volume significantly decreased after tea tree oil application (10 min after tea tree oil application, P = 0·0004, Mann,Whitney U-test). Conclusions ,This is the first study to show experimentally that tea tree oil can reduce histamine-induced skin inflammation. [source]

    Contribution of OCT to evaluate macular disease in JIA associated uveitis

    Purpose To examine the frequency and characteristics of macular lesions observed in Juvenile Idiopathic Arthritis (JIA) uveitis, using Optical Coherence Tomography (OCT). Methods In this cross-sectional study, 38 consecutive patients were recruited from a tertiary referral center in uveitis. All eyes with JIA uveitis underwent complete ophthalmic examination including OCT 3. Exclusion criterion was the inability to obtain OCT scans. Flare and visual acuity were also analyzed by using linear regression. Results We analyzed foveal thickness (FT) and central foveal thickness (CFT) using the software mapping, to describe macular lesions in 61 eyes. Maculopathy was observed in 51 eyes (84%), compared to 12% in the literature (P<0.0001) and comprised four types: perifoveolar thickening in 45 eyes (74%), macular edema in 29 eyes (48%), foveal detachment in 11 eyes (18%), and atrophic changes in 6 eyes (10%). Only 4 eyes did not demonstrate any lesion. Conclusion Among children with JIA-uveitis, macular involvement is frequent, and characterized by perifoveolar thickening and serous retinal detachment. OCT is a non-invasive instrument. It may easily show this maculopathy, which could impair visual function, and conditioned a therapeutic intensification. [source]

    2006,2008 Annual Review on Aerial Infrared Decoy Flares

    Ernst-Christian Koch
    Abstract The most recent progress in the field of advanced aerial infrared decoy flare technology is documented. 71 references from the public domain are given. For the last review please see Ref. [2]. [source]

    High risk of hepatitis B-virus reactivation after hematopoietic cell transplantation in hepatitis B core antibody-positive patients

    Kosei Matsue
    Abstract We investigated the serological changes in hepatitis B virus (HBV)-related markers in 55 and 26 hepatitis B surface antigen (HBsAg)-negative patients undergoing allogeneic and autologous stem cell transplantation, respectively, over the past 4 yr. Five of the 17 allogeneic and one of the five autologous patients with pretransplant anti-hepatitis B core antigen antibodies (anti-HBc) were HBsAg-positive after transplantation, whereas none of the patients negative for anti-HBc were HBsAg-positive in both groups. All patients who became HBsAg-positive received steroid-containing immunosuppressive therapy for chronic graft versus host disease (GVHD) or myeloma. Four of the six patients developed flare of HBV hepatitis, and two patients did not. One patient developed fulminant hepatitis treated with lamivudine and plasma exchange. Other five patients received entecavir from the detection of HBsAg. Although HBV-DNA levels became below the limit of detection in all patients, HBsAg positivity remained in three patients after 6 months of treatment. We concluded that anti-HBc positivity is a risk factor for reactivation of HBV after both autologous and allogeneic transplantation, and HBV-related markers should be monitored regularly in these patients. We also stress the efficacy of pre-emptive use of antiviral agents in controlling HBV replication and limiting hepatic injury due to reactivation of HBV in these patients. [source]

    The Neurogenic Vasodilator Response to Endothelin-1: A Study in Human Skin In Vivo

    Ruwani Katugampola
    We have investigated the mediators and mechanisms underlying the vasodilator effects of the potent vasoactive peptide, endothelin-1 (ET-1) and its isomers ET-2 and ET-3 in human skin, in vivo, using cutaneous microdialysis to quantify the release of mediators within the dermal response and scanning laser Doppler imaging to measure changes in blood flux. The effects of local anaesthesia, inhibition of nitric oxide synthase (NOS) by L-NAME and ET receptor blockade on the ET-induced vascular response were also investigated. ET-1, -2 and -3 all caused a dose-dependent area of pallor surrounded by a long-lasting flare which was accompanied by a short-lived burning pruritus. The concentration of nitric oxide (NO) in dialysate collected within the pallor response to 5 ,M ET-1 (1.43 ± 0.64 ,M, n = 5) was not significantly different from baseline levels collected prior to injection (0.86 ± 0.38 ,M) whilst that in the flare increased to reach a peak value of 2.28 ± 0.61 ,M at between 4 and 10 min after intradermal injection (P < 0.004). Pretreatment with local anaesthetic slowed the development of the flare and significantly reduced its size by up to 52% at 20 min after injection (P < 0.05) but had no significant effect on the central pallor. L-NAME, delivered by dialysis also caused a significant reduction in the ET-1-induced flare (P < 0.005). Bosentan, the non-selective ETA/ETB antagonist, when given by dialysis at the site of injection, reduced the area of both the ET-1-induced pallor and surrounding flare by 41 and 26%, respectively. No significant increase in tissue histamine was measured within either the pallor or flare response to ET-1, -2 or -3. Together these data confirm that the vasodilator response to endothelin-1 in human skin is neurogenic in origin and that it is in part mediated by the local release of nitric oxide. There appears to be little evidence for the involvement of mast cell-derived histamine in the initiation or modulation of ET-induced vasodilatation, in vivo. [source]

    The SGR 1806-20 magnetar signature on the Earth's magnetic field

    M. Mandea
    SUMMARY SGRs denote ,soft ,-ray repeaters', a small class of slowly spinning neutron stars with strong magnetic fields. On 2004 December 27, a giant flare was detected from magnetar SGR 1806-20. The initial spike was followed by a hard-X-ray tail persisting for 380 s with a modulation period of 7.56 s. This event has received considerable attention, particularly in the astrophysics area. Its relevance to the geophysics community lies in the importance of investigating the effects of such an event on the near-Earth electromagnetic environment. However, the signature of a magnetar flare on the geomagnetic field has not previously been investigated. Here, by applying wavelet analysis to the high-resolution magnetic data provided by the CHAMP satellite, a modulated signal with a period of 7.5 s over the duration of the giant flare appears in the observed data. Moreover, this event was detected by the energetic ion counters onboard the DEMETER satellite. [source]

    Serum alanine aminotransferase flares during interferon treatment of chronic hepatitis B: Is sustained clearance of HBV DNA dependent on levels of pretreatment viremia?

    HEPATOLOGY, Issue 5 2001
    Satheesh Nair
    During interferon treatment of chronic hepatitis B, an alanine aminotransferase (ALT) flare may herald a sustained loss of viral replication, but the relationship between virologic response, the extent of a flare, and pretreatment hepatitis B virus (HBV) DNA level has not been defined. We retrospectively examined the impact of an ALT flare on sustained virologic response in 121 interferon-treated patients and 42 untreated controls with either low-level (<100 pg/mL) or high-level (,100 pg/mL) viremia. The degree of ALT flare was classified as mild (increase in ALT of 86-171 IU/L above baseline), moderate (increase of 172 to 343 IU/L above baseline), and severe (increase of ,344 IU/L above baseline). Undetectable serum HBV DNA and hepatitis B e antigen (HBeAg) loss were significantly more likely at the end of follow-up in patients having a flare (P = .0001 and .001, respectively). In the high viremia group, a proportionate increase in virologic response was observed as the degree of flare increased. By multivariate analysis, high baseline HBV DNA, high pretreatment ALT, and both moderate and severe ALT flare were independently predictive of a virologic response with severe flare being the most powerful predictor for a sustained loss of serum HBV DNA (odds ratio, 5.3; P = .004). Severe flare was predictive of a virologic response in the high but not low viremia group. We conclude that a virologic response in patients with high-level viremia is dependent on the degree of ALT flare. Induction of a robust flare may enhance virologic response when high-level viremia is detected. [source]

    Spontaneous HBeAg seroconversion and loss of hepatitis B virus DNA after acute flare due to development of drug resistant mutants during entecavir monotherapy

    Ri-Cheng Mao
    Aims:, Patients with chronic hepatitis B virus (HBV) infection under entecavir (ETV) treatment develop resistant mutants with viral rebound. Here, we report an interesting case of spontaneous loss of HBV-DNA and seroconversion following an acute flare after the development of ETV-resistant mutants. This patient received ETV after lamivudine breakthrough. Methods:, Cloning and sequence analysis of the HBV reverse transcriptase (RT) region were performed with seven samples during ETV therapy. In addition, two full-length HBV genomes derived from samples before and after the emergence of ETV resistance were sequenced. Results:, ETV resistant mutants appeared at week 228, with virological and biochemical rebound at the same time. Unexpectedly, HBeAg seroconversion occurred 8 weeks later. The viral load decreased and became undetectable from week 252. Analysis of HBV isolates in the patient at week 124 revealed that wild-type HBV was predominant at that time and ETV resistant mutants were not found among 20 clones. Interestingly, a new mutant type with rtL180M+rtT184L was found alongside rtL180M+rtT184L+rtM204V/I at week 228 and appeared to develop independently, according to the sequence analysis. In contrast to the previously identified ETV resistant mutants, it did not carry the rtM204V/I mutations. Conclusion:, The data presented here indicates that the flare following the emergence of ETV resistant mutants may reflect immune-mediated control of HBV infection, leading to a spontaneous loss of HBV-DNA and seroconversion. [source]

    Risk factors and characteristics of extent progression in ulcerative colitis

    María Josefina Etchevers MD
    Abstract Background: The main objective was to identify risk factors for extent progression in distal ulcerative colitis. The secondary objective was to determine clinical characteristics of disease at the time of progression. Methods: Data were obtained from a prospective database. Distal colitis was defined as disease limited to rectum and sigmoid colon (n = 178), extensive colitis as involvement of at least the descending colon (n = 179), and colitis with progression when there was a change of category from distal to extensive (n = 63). To study clinical characteristics at the time of progression, a nested case,control study was performed. Results: Compared to distal colitis, colitis with progression was associated to significantly higher prevalence of extraintestinal manifestations (42.9% versus 15.5%) steroid-refractory course (28.0% versus 2.2%), requirement of thiopurines (44.3% versus 17.3%), cyclosporine (25.4% versus 1.9%), infliximab (9.5% versus 1.2%), surgery (20.6% versus 0.6%), and incidence of neoplasia (6.3% versus 0%). However, these differences appeared after disease progression. Regression analysis demonstrated that preexisting independent predictive factors for progression were younger age at diagnosis (hazard ratio [HR] 0.979 95% confidence interval [CI] 0.959,0.999) and presence of sclerosing cholangitis (HR 12.83, 95% CI 1.36,121.10). The nested case,control study showed that at the time of progression the flare was more severe in cases than in matched controls, with significant differences in markers of disease severity, therapeutic requirements, hospitalizations, and surgery. Conclusions: Patients with distal ulcerative colitis diagnosed at a younger age or with associated sclerosing cholangitis are at higher risk for progression. Disease flare associated with progression follows a severe course with high therapeutic requirements. (Inflamm Bowel Dis 2009) [source]

    Muscle performance in patients with Crohn's disease in clinical remission

    Jean-Baptiste Wiroth PhD
    Abstract Background: Because patients with Crohn's disease (CD) often show increased energy expenditure, nutritional deficiencies, and general fatigue, all which may persist after a flare, we hypothesized that CD could alter muscle mass and function. This study aimed to assess muscle strength and endurance in CD patients in clinical remission and the influencing factors. Methods: Forty-one outpatients (17 men and 24 women; age, 37 ± 10 yr), in remission (CD Activity Index < 150) for >3 months, and 25 age-matched healthy controls (10 men and 15 women; age, 37 ± 13 yr) were evaluated. Evaluation included a sit-up test, hand-grip strength test, hand-grip endurance test, lower limb strength test, and lower limb endurance test (LE), as well as a measure of physical activity. Results: No significant difference was found between CD and control groups regarding weight, height, body mass index, fat mass, and fat-free mass. Strength performance was lower in CD subjects compared with controls, particularly for lower limb indexes: lower limb strength test (,24.6%, P < 0.001), LE (,25.8%, P < 0.001), and sit-up test (,25.1%, P < 0.001). Previous disease severity, disease duration, the cumulative dose of glucocorticosteroids, current inflammation, and global habitual physical activity did not affect muscle performance. A recent use of steroids improved LE. Conclusions: CD patients in clinical remission have decreased muscle function that may affect their quality of life. This pattern is reflected by reduced strength and endurance indexes, particularly for lower limbs. The reasons for these changes need further study. Strength training should be assessed in these patients. [source]

    An in vitro comparison of canal preparation using two automated rotary nickel,titanium instrumentation techniques

    S. J. Jardine
    Abstract Aim The aim of this study was to compare the efficacy of root canal preparation using two automated rotary nickel,titanium instrumentation techniques with a double flared balanced forces hand preparation technique, using stainless steel files in extracted human teeth. Methodology Sixty root canals in extracted human teeth were matched for curvature, length and diameter and divided evenly between three groups (group 1 = double flare using Flexofiles®, group 2 = rotary nickel,titanium using McXIM® instruments and group 3 = rotary nickel,titanium using Profile® .04 TaperTM Series 29 instruments). The instruments were used according to the manufacturer's instructions in a torque controlled motor and handpiece (groups 2 and 3) and according to a predetermined procedure in group 1. A standardized radiographic technique using mercury as a contrast medium was used to evaluate the canal shape before and after preparation in the plane of maximum curvature. The pre- and postoperative radiographic images were compared against each other and with a predicted ,ideal preparation' calculated from a projection of the final instrument dimensions. The outcome measures were changes in canal dimensions as quantified by measuring the changes in the position of the inner and outer wall at 1 mm intervals. Alteration in canal curvature could be inferred by comparison with the ideal preparation. Results The degree of canal curvature did not influence the effectiveness of any of the techniques. The results showed no statistically significant differences in the outcome measures between the groups (two-way anova). There were no significant differences in canal wall position changes at any level except the apical three, where significantly less change occurred in all groups (P = 1%). Instruments fractured in three canals, with acute curves in groups 2 and 3. Conclusions Canal curvatures were equally and well maintained following preparation in all the groups, as long as the instrument did not fracture. [source]

    Cutaneous paragonimiasis with flare up after treatment: A clinical case from Laos

    E. Clyti MD
    No abstract is available for this article. [source]

    Once-daily desloratadine improves the signs and symptoms of chronic idiopathic urticaria: a randomized, double-blind, placebo-controlled study

    Johannes Ring MD
    Background Chronic idiopathic urticaria (CIU) is the most common type of chronic urticaria, and pruritus is the most prominent symptom. Antihistamines are the first-line treatment for CIU. Sedation and anticholinergic adverse effects are often experienced with the first-generation antihistamines and there is a risk of cardiovascular adverse effects and drug interactions with some second-generation agents. Hence, new treatment options are needed. Desloratadine is a new, potent, nonsedating antihistamine that has an excellent cardiovascular safety profile. Methods This was a multicenter, randomized, double-blind, placebo-controlled study designed to determine the efficacy and safety of desloratadine in the treatment of moderate-to-severe CIU. A total of 190 patients, aged 12,79 years, with at least a 6-week history of CIU and who were currently experiencing a flare of at least moderate severity, were randomly assigned to therapy with desloratadine 5 mg or placebo once daily for 6 weeks. Twice daily, patients rated the severity of CIU symptoms (pruritus, number of hives, and size of largest hive), as well as the impact of CIU symptoms on sleep and daily activity. Patients and investigators jointly evaluated therapeutic response and overall condition. Safety evaluations included the incidence of treatment-emergent adverse events, discontinuations due to adverse events, and changes from baseline in vital signs, laboratory parameters, and ECG intervals. Results Desloratadine was superior to placebo in controlling pruritus and total symptoms after the first dose and maintained this superiority to the end of the study. Measures of sleep, daily activity, therapeutic response, and global CIU status were also significantly better with desloratadine after the first dose; these clinical benefits were also maintained throughout the 6-week study. No significant adverse events occured. Conclusions Desloratadine 5 mg daily is a safe and effective treatment for CIU with significant benefits within 24 h and maintained through the treatment period. [source]

    Management of systemic lupus erythematosus in the coming decade: potentials and challenges

    Hiok Hee CHNG
    Abstract The management of systemic lupus erythematosus (SLE) has improved in the past 50 years, but there is still a 3,5-fold increased mortality compared to the general population, with major organ failure due to active disease, infection and cardiovascular disease as the major challenges for the coming decade. Research advances at cellular, molecular and genetic levels enhance our understanding of the immunopathogenic mechanisms of SLE, leading to the development of drugs targeting specific sites of immune dysregulation , with therapies directed at cytokines, B- and T-cells, and their interactions showing promise. Advances are expected in the field of haematopoietic stem cell transplant (HSCT) as a therapeutic option for a subset of patients. Furthermore, some non-traditional immunomodulating therapies like statins, leflunomide and tacrolimus may prove useful as alternative or adjunct treatment in some patients. A better understanding of how current immunosuppressants act at the cellular and molecular level should guide the re-evaluation of the indications, doses and duration of therapy in clinical trials using these agents, many of which have not been subjected to proper double-blinded placebo-controlled studies. Research on triggers of SLE onset and flare of activity continues to yield information helpful in prevention. The evidence on the impact of psychosocial and economic factors on the outcome of SLE is overwhelming and the rheumatology community should enlist the assistance of other healthcare professionals, patient advocates and local health authorities to address these issues pertinent to good patient care and outcome. [source]

    Question of ALT flare during switch to adefovir from lamivudine: A single center open-label, randomized, safety study (June 17, 2005 to February 5, 2009),

    Hie-Won L. Hann
    Abstract Earlier clinical studies have reported an ALT flare greater than 10 times the upper limit of normal in some patients with chronic hepatitis B when their lamivudine (LAM) treatment was switched to adefovir (ADV) therapy. The current study compared the safety of switching directly to ADV versus overlapping LAM and ADV for 3 months followed by ADV monotherapy. Patients with chronic hepatitis B receiving LAM therapy for ,6 months were eligible for the study regardless of the presence of LAM resistance, HBeAg status or serum ALT levels. Eighteen patients (13 males) were randomized to direct switch to ADV and 17 patients (10 males) to overlap. HBV-DNA, ALT, albumin, and total bilirubin were assayed at baseline, 3, 6, 9, and 12 months. Study drugs were discontinued at the end of 12 months with the follow up at 3 and 6 months. The decision to continue antiviral therapy was made at the discretion of the investigator. Baseline ALT levels were similar between the direct switch and overlap group: median ALT (U/L) was 44.0 (16,266) and 33.0 (19,367) for direct switch for overlap group, respectively (P,=,0.42). No ALT flare was noted at 3 months in either group: median ALT decreased from 44.0 to 34.5,U/L in the direct switch group, and from 33.0 to 23.0 in the overlap group. Furthermore, no patient in either group exhibited ALT flare throughout the 12 months. This study did not show an ALT flare during switch to ADV at 3 months or at any time later. J. Med. Virol. 82:1489,1493, 2010. © 2010 Wiley-Liss, Inc. [source]

    Clinical and virological characteristics of lamivudine resistance in chronic hepatitis B patients: A single center experience

    Jian Sun
    Abstract We have investigated the characteristics of lamivudine-resistant strains in patients with chronic hepatitis B in Guangdong, China, where the predominant genotypes are B and C. Two hundred forty-seven patients treated with lamivudine in Nanfang Hospital were followed-up. Patients with hepatitis B e antigen (HBeAg) positive and hepatitis B virus (HBV)-DNA levels over 7.5,×,106 copies/ml at baseline had a shorter time to the selection of YMDD mutant (P,=,0.02 and 0.00, respectively). The detection of YMDD mutant precedes HBV-DNA breakthrough and alanine transaminase (ALT) flare in about 2 and 3 months, respectively. The ALT flare after the appearance of YMDD mutants was more evident in HBeAg positive patients than HBeAg negative patients (P,=,0.02). After emergence of YMDD mutant, the HBV-DNA level was significantly higher in genotype C patients compared with genotype B patients (P,=,0.02). No significant difference of YMDD mutant pattern was found between patients with genotype B and C. Four kinds of new mutants were found in over two patients including rtL80I, rtG172E, rtG174C, and rtG172E/rtG174C. In vitro transfection and real-time analysis showed that rtG172E, rtG174C, and rtG172E/rtG174C mutants had a decreased replication competence compared with wild type (33%, 27%, and 15% of the wild type HBV, respectively). Our result suggest that genotypic monitoring of YMDD mutant is important for the management of patients treated with lamivudine. J. Med. Virol. 75:391,398, 2005. © 2005 Wiley-Liss, Inc. [source]

    Effectiveness and safety of a prevention-of-flare-progression strategy with pimecrolimus cream 1% in the management of paediatric atopic dermatitis

    B Sigurgeirsson
    Abstract Objective, This study was performed to investigate the efficacy and safety of a prevention-of-flare-progression strategy with pimecrolimus cream 1% in children and adolescents with atopic dermatitis (AD). Methods, A 26-week multi-centre, randomized, double-blind, vehicle-controlled study was conducted in 521 patients aged 2,17 years, with a history of mild or moderate AD, who were clear/almost clear of disease before randomization to pimecrolimus cream 1% (n = 256) or vehicle cream (n = 265). Twice-daily treatment with study medication was started at the first signs and/or symptoms of recurring AD. If, despite the application of study medication for at least 3 days, AD worsened (as confirmed by the investigator), treatment with a moderately potent topical corticosteroid (TCS) was allowed in both groups. The primary efficacy end point was the number of days on study without TCS use for a flare. Results, The mean number of TCS-free days was significantly higher (P < 0.0001) in the pimecrolimus cream 1% group (160.2 days) than in the control group (137.7 days). On average, patients on pimecrolimus cream 1% experienced 50% fewer flares requiring TCSs (0.84) than patients on vehicle cream (1.68) (P < 0.0001). Patients on pimecrolimus cream 1% also had fewer unscheduled visits (87) than patients on vehicle cream (246). Conclusions, In children and adolescents with a history of mild or moderate AD but free/almost free of signs or symptoms of the disease, early treatment of subsequent AD exacerbations with pimecrolimus cream 1% prevented progression to flares requiring TCS, leading to fewer unscheduled visits and reducing corticosteroid exposure. [source]

    Effective management of a psoriatic flare with narrowband UVB phototherapy during efalizumab therapy without discontinuing treatment

    JM Carrascosa

    Autonomic skin responses in females with Fabry disease

    Anette T. Mřller
    Abstract Fabry disease is a genetic lysosomal disorder with dysfunction of the lysosomal enzyme ,-galactosidase A causing accumulation of glycolipids in multiple organs including the nervous system and with neuropathy as a prominent manifestation. Neurological symptoms include pain and autonomic dysfunction. This study examined peripheral autonomic nerve function in 19 female patients with Fabry disease and 19 sex and age-matched controls by measuring (1) sweat production following acetylcholine challenge; (2) the sympathetically mediated vasoconstrictor responses to inspiratory gasp, stress, and the cold pressor test; and (3) cutaneous blood flow following capsaicin. The vasoconstrictor response to inspiratory gasp was increased in Fabry patients compared to controls (p = 0.03), while the response to cold and mental stress did not change. Female patients with Fabry disease had a reduced sweat response to iontophoresis of acetylcholine (p = 0.04) and a smaller capsaicin-induced flare compared to controls. These findings suggest that female patients both have an impaired C-fiber function and local abnormalities in blood vessels and sweat glands. [source]

    The first broad-band X-ray study of the Supergiant Fast X-ray Transient SAX J1818.6,1703 in outburst

    L. Sidoli
    ABSTRACT The Supergiant Fast X-ray Transient (SFXT) SAX J1818.6,1703 underwent an outburst on 2009 May 6 and was observed with Swift. We report on these observations which, for the first time, allow us to study the broad-band spectrum from soft to hard X-rays of this source. No X-ray spectral information was available on this source before the Swift monitoring. The spectrum can be deconvolved well with models usually adopted to describe the emission from HMXB X-ray pulsars, and is characterized by a very high absorption, a flat power law (photon index ,0.1,0.5) and a cut-off at about 7,12 keV. Alternatively, the SAX J1818.6,1703 emission can be described with a Comptonized emission from a cold and optically thick corona, with an electron temperature kTe= 5,7 keV, a hot seed photon temperature, kT0, of 1.3,1.4 keV and an optical depth for the Comptonizing plasma, ,, of about 10. The 1,100 keV luminosity at the peak of the flare is 3 × 1036 erg s,1 (assuming the optical counterpart distance of 2.5 kpc). These properties of SAX J1818.6,1703 resemble those of the prototype of the SFXT class, XTE J1739,302. The monitoring with Swift/XRT reveals an outburst duration of about 5 d, similar to other members of the class of SFXTs, confirming SAX J1818.6,1703 as a member of this class. [source]

    Modification of the gamma-ray spectra by internal absorption in optically violently variable blazars: the example cases of 3C 273 and 3C 279

    J. Sitarek
    ABSTRACT Recent observations with the low-threshold Cherenkov telescopes proved that sub-TeV ,-rays are able to arrive from active galaxies at relatively large distances in spite of the expected severe absorption in the extragalactic background light (EBL). We calculate the ,-ray spectra at TeV energies from two example optically violently variable quasars, 3C 273 and 3C 279, assuming that ,-rays are injected in the inner parts of the jets launched by the accretion discs. It is assumed that ,-rays in the broad energy range (from MeV up to TeV) are produced in these blazars with a power-law spectrum with the spectral index as observed from these objects by the EGRET telescope at GeV energies. We take into account the internal absorption of these ,-rays by considering a number of models for the radiation field surrounding the jet. The classical picture of a relativistic blob in a jet for the injection of primary ,-rays is considered, with the injection rate of ,-rays as observed by the EGRET telescope in the GeV energy range. The results of calculations are compared with positive detection and the upper limits on the sub-TeV ,-ray fluxes from these two sources. It is concluded that, even with the Stecker EBL model, the level of ,-ray emission from 3C 279 is close to the recent measurements in the sub-TeV ,-ray energies, provided that the injected ,-ray spectrum extends from the GeV energies over the next two decades with this same spectral index. We also suggest that a flare with a time-scale of a few days from 3C 273 could be detected by the MAGIC II stereo telescopes. [source]

    Helioseismic analysis of the solar flare-induced sunquake of 2005 January 15

    H. Moradi
    ABSTRACT We report the discovery of one of the most powerful sunquakes detected to date, produced by an X1.2-class solar flare in active region AR10720 on 2005 January 15. We used helioseismic holography to image the source of seismic waves emitted into the solar interior from the site of the flare. Acoustic egression power maps at 3 and 6 mHz with a 2-mHz bandpass reveal a compact acoustic source strongly correlated with impulsive hard X-ray and visible-continuum emission along the penumbral neutral line separating the two major opposing umbrae in the ,-configuration sunspot that predominates AR10720. At 6 mHz the seismic source has two components, an intense, compact kernel located on the penumbral neutral line of the ,-configuration sunspot that predominates AR10720, and a significantly more diffuse signature distributed along the neutral line up to ,15 Mm east and ,30 Mm west of the kernel. The acoustic emission signatures were directly aligned with both hard X-ray and visible continuum emission that emanated during the flare. The visible continuum emission is estimated at 2.0 × 1023 J, approximately 500 times the seismic emission of ,4 × 1020 J. The flare of 2005 January 15 exhibits the same close spatial alignment between the sources of the seismic emission and impulsive visible continuum emission as previous flares, reinforcing the hypothesis that the acoustic emission may be driven by heating of the low photosphere. However, it is a major exception in that there was no signature to indicate the inclusion of protons in the particle beams thought to supply the energy radiated by the flare. The continued strong coincidence between the sources of seismic emission and impulsive visible continuum emission in the case of a proton-deficient white-lightflare lends substantial support to the ,back-warming' hypothesis, that the low photosphere is significantly heated by intense Balmer and Paschen continuum-edge radiation from the overlying chromosphere in white-light flares. [source]

    The GRB early optical flashes from internal shocks: application to GRB 990123, GRB 041219a and GRB 060111b

    D. M. Wei
    ABSTRACT With the successful launch of the Swift Gamma-ray Burst Explorer, it is widely expected that the prompt optical flashes like GRB 990123 would be easily detected. However, the observations show that for a number of Gamma-ray bursts (GRBs) no early optical flash has been detected, which indicates that the reverse shock emission must be suppressed. Here we explore the possibility that the optical flash may arise from the internal shock emission. For GRB 990123 and GRB 060111b, although their optical emission are not correlated with the gamma-ray emission, we propose here that their optical and gamma-ray emission may arise from different internal shocks (which can be formed by collision of different shells), and find that, under certain circumstances, the optical flashes of GRB 990123 and GRB 060111b can well be explained by the internal shock model. For GRB 041219a, the prompt optical emission was correlated with the gamma-ray emission, which can also be explained by the internal shock model if we assume the optical emission was the low-energy extension of the gamma-ray emission, and we find its redshift is about z, 0.2. As for GRB 050904, we have shown in previous paper that the optical flash was produced by synchrotron radiation and the X-ray flare was produced by the synchrotron,self-Compton (SSC) mechanism. Therefore we conclude that the early optical flashes of GRBs can usually arise from the internal shock emission. Meanwhile in our model since the shells producing the optical flashes would be easily disrupted by other shells, so we suggest that the bright optical flash should not be common in GRBs. In addition, we also discussed the SSC emission in the internal shock model, and find that for different values of parameters, there would be several kinds of high-energy emission (at ,100 keV, ,10 MeV or GeV) accompanying the optical flash. For a burst like GRB 990123, a GeV flare with fluence about 10,8 erg cm,2 s,1 is expected, which might be detected by the GLAST satellite. [source]

    The narrow-line quasar NAB 0205 + 024 observed with XMM,Newton

    L. C. Gallo
    ABSTRACT The XMM,Newton observation of the narrow-line quasar NAB 0205+024 reveals three striking differences since it was last observed in X-rays with ASCA. First, the 2,10 keV power law is notably steeper. Secondly, a hard X-ray flare is detected, very similar to that seen in I Zw 1. Thirdly, a strong and broad emission feature is detected with the bulk of its emission redward of 6.4 keV, and extending down to ,5 keV in the rest frame. The most likely explanation for the broad feature is neutral iron emission emitted from a narrow annulus of an accretion disc close to the black hole. The hard X-ray flare could be the mechanism that illuminates this region of the disc, allowing for the emission line to be detected. The combination of effects can be understood in terms of the ,thunder-cloud' model proposed by Merloni & Fabian. [source]

    Cross-spectral analysis of the X-ray variability of Markarian 421

    Y. H. Zhang
    ABSTRACT Using the cross-spectral method, we confirm the existence of the X-ray hard lags discovered with cross-correlation function technique during a large flare of Mrk 421 observed with BeppoSAX. For the 0.1,2 versus 2,10 keV light curves, both methods suggest sub-hour hard lags. In the time domain, the degree of hard lag, i.e. the amplitude of the 3.2,10 keV photons lagging the lower energy ones, tends to increase with the decreasing energy. In the Fourier frequency domain, by investigating the cross-spectra of the 0.1,2/2,10 keV and the 2,3.2/3.2,10 keV pairs of light curves, the flare also shows hard lags at the lowest frequencies. However, with the present data, it is impossible to constrain the dependence of the lags on frequencies even though the detailed simulations demonstrate that the hard lags at the lowest frequencies probed by the flare are not an artefact of sparse sampling, Poisson and red noise. As a possible interpretation, the implication of the hard lags is discussed in the context of the interplay between the (diffusive) acceleration and synchrotron cooling of relativistic electrons responsible for the observed X-ray emission. The energy-dependent hard lags are in agreement with the expectation of an energy-dependent acceleration time-scale. The inferred magnetic field (B, 0.11 G) is consistent with the value inferred from the spectral energy distributions of the source. Future investigations with higher quality data that show whether or not the time-lags are energy-/frequency-dependent will provide a new constraint on the current models of the TeV blazars. [source]

    The X-ray variability of the Seyfert 1 galaxy MCG,6-30-15 from long ASCA and RXTE observations

    Julia C. Lee
    We present an analysis of the long Rossi X-ray Timing Explorer (RXTE) observation of the Seyfert 1 galaxy MCG,6-30-15, taken in 1997 July. We have previously used the data to place constraints for the first time on the iron abundance,reflection fraction relationship, and now expand the analysis to investigate in detail the spectral X-ray variability of the object. Our results show that the behaviour is complicated. We find clear evidence from colour ratios and direct spectral fitting that changes to the intrinsic photon index are taking place. In general, spectral hardening is evident during periods of diminished intensity, and in particular, a general trend for harder spectra is seen in the period following the hardest RXTE flare. Flux-correlated studies further show that the 3,10 keV photon index ,3,10 steepens, while that in the 10,20 keV band, ,10,20, flattens with flux. The largest changes come from the spectral index below 10 keV; however, changes in the intrinsic power-law slope (shown by changes in ,3,10), and reflection (shown by changes in ,10,20) both contribute in varying degrees to the overall spectral variability. We find that the iron-line flux FK, is consistent with being constant over large time intervals on the order of days (although tentative evidence exists which show that FK, changes on shorter time intervals of order ,10 ks during time periods surrounding flare events), and has an equivalent width which anticorrelates with the continuum flux and reflection fraction. A possible interpretation for the iron-line flux constancy and the relative Compton reflection increase with flux from the flux-correlated data is an increasing ionization of the emitting disc surface, while spectral analysis of short time intervals surrounding flare events hints tentatively at observed spectral responses to the flare. We present a simple model for partial ionization where the bulk of the variability comes from within 6rg. Temporal analysis further provides evidence for possible time (,1000 s) and phase (,,0.6 rad) lags. Finally, we report an apparent break in the power density spectrum (,4,5×10,6 Hz) and a possible 33-hour period. Estimates for the mass of the black hole in MCG,6-30-15 are discussed in the context of spectral and temporal findings. [source]

    Soft gamma-ray repeater giant flares in the BATSE short gamma-ray burst catalogue: constraints from spectroscopy

    Davide Lazzati
    ABSTRACT The giant flare observed on 2004 December 27 from SGR 1806,20 has revived the idea that a fraction of short (<2 s) gamma-ray bursts (GRBs) are due to giant flares from soft gamma-ray repeaters (SGRs) located in nearby galaxies. One of the distinguishing characteristics of these events is the thermal (blackbody) spectrum with temperatures ranging from ,50 to ,180 keV, with the highest temperature observed for the initial 0.2-s spike of the 2004 December 27 event. We have analysed the spectra of a complete sample of short GRBs with peak fluxes greater than 4 photon s,1 cm,2 detected by BATSE. Of the 115 short GRBs so selected, only 76 had sufficient signal-to-noise ratio to allow the spectral analysis. We find only three short GRBs with a spectrum well fitted by a blackbody, with 60 ,kT, 90 keV, albeit with a considerably longer duration (i.e. ,1 s) and a more complex light curve than the 2004 December 27 event. This implies a stringent limit on the rate of extragalactic SGR giant flares with spectral properties analogous to the December 27 flare. We conclude that up to 4 per cent of the short GRBs could be associated with giant flares (2, confidence). This implies that either the distance to SGR 1806,20 is smaller than 15 kpc or the rate of Galactic giant flares is lower than the estimated 0.033 yr,1. [source]

    H1 -antihistaminic activity of cetirizine and fexofenadine in allergic children

    F. Estelle R. Simons
    The clinical pharmacology of H1 -antihistamines has not yet been optimally studied in children and other special groups of patients. Our objective was to determine the onset, extent, and duration of H1 -antihistaminic activity of cetirizine and fexofenadine in the pediatric population. We performed a prospective, randomized, placebo-controlled, double-blind, crossover, single-dose study of these H1 -antihistamines in 15 allergic children, mean±SEM age 8.8±0.5 years. We used suppression of the histamine-induced wheal and flare as the primary outcome. Compared with pre-dose baseline, cetirizine 10 mg suppressed the wheals significantly (p,0.05) from 2 to 24 h and the flares significantly from 1 to 24 h, achieving 77±SEM 10% to 86±9% suppression of the wheal from 2 to 7 h and 85±6% to 88±6% suppression of the flare from 2 to 24 h, inclusive. Compared with baseline, fexofenadine 30 mg did not suppress the wheals or flares significantly at any time, achieving 40±9% to 54±9% wheal suppression from 2 to 7 h and 45±11% to 68±9% flare suppression from 2 to 7 h, inclusive. Compared with placebo, cetirizine suppressed the wheals and flares significantly from 2 to 24 h. Compared with placebo, fexofenadine suppressed the wheals significantly at 4 and 6 h, and the flares from 4 to 7 h. Cetirizine suppressed the wheals and flares significantly more than fexofenadine at 2 h (wheals), and at 3 and 24 h (flares). Placebo did not suppress the wheals and flares significantly at any time. In children age 6,11 years, cetirizine 10 mg has a rapid onset of H1 -antihistaminic activity, a 24-h duration of action, and greater H1 -activity than fexofenadine 30 mg. Higher doses of fexofenadine should be tested in children. [source]

    Clinical pharmacology of the H1 -receptor antagonists cetirizine and loratadine in children

    F. Estelle R. Simons
    H1 -receptor antagonists are widely used in children but are not as well-studied in children as they are in adults. Our objective was to determine the onset and duration of action and the relative potency of the H1 -receptor antagonists cetirizine and loratadine in children. We performed a prospective, randomized, placebo-controlled, double-blind, crossover, single-dose study of cetirizine and loratadine using suppression of the histamine-induced wheal and flare as the primary outcome. In 15 allergic children, mean age 9 years, compared with baseline, cetirizine (10 mg) suppressed the wheals and flares significantly from 0.25 to 24 h, achieving nearly 100% of flare suppression from 2 to 24 h, inclusive, and loratadine (10 mg) suppressed the wheals and flares significantly from 0.75 to 24 h, inclusive. Cetirizine suppressed the wheals and flares significantly more than loratadine from 0.25 to 1 h, inclusive, and at 0.5, 1, 2, 3, 5, 6, 7, and 24 h, respectively. Placebo also suppressed the wheal and flare significantly at some assessment times. Cetirizine and loratadine both have excellent antihistaminic activity in children, with a rapid onset of action and a 24-h duration of action in this population. [source]