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Query: UMLS:C0018681 (headache)
 56,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is still some controversy about alterations in velocity of blood flow and in cerebral vasomotor reactivity of intracranial arteries in migraineurs during the interictal phase. By means of simultaneous bilateral transcranial Doppler ultrasonography we, therefore, assessed intracranial blood flow velocities and cerebrovascular reactivity to carbon dioxide of all three basal brain arteries in 20 migraineurs during the interictal phase and 30 nonheadache-prone control subjects. Mean blood flow velocities were higher in migraineurs than in controls in all three arteries on both sides, with a significant difference (P < 0.05) for the right anterior cerebral artery and middle cerebral artery under basal conditions and for the right posterior cerebral artery during hypercapnia. Similarly, the cerebrovascular reactivity to carbon dioxide was always higher in patients than in controls, with a significant difference for the left anterior and the right middle cerebral arteries (P < 0.05) and the right posterior cerebral artery (P < 0.01). The broad overlap of cerebrovascular blood flow velocities and CO2 reactivities in patients and controls precluded identification of values diagnostic of migraine. Nevertheless, transcranial Doppler ultrasonography offers the opportunity to noninvasively monitor cerebral blood flow parameters and, therefore, represents a valuable tool for vascular research in migraine.
Headache 1998 Sep
PMID:Cerebral blood flow and CO2 reactivity in interictal migraineurs: a transcranial Doppler study. 1139 4

With the increased utilization of school buildings on a year-round basis, school indoor air quality has become a national concern. The purpose of this study was to evaluate possible associations between ventilation system type and occupant perception of indoor air quality. Staff (n = 403) from 12 schools completed a self-administered questionnaire. Carbon dioxide (CO2) levels, air exchange rates, and particle counts were also measured for each school. Schools with unit ventilator (UV) systems had the lowest mean CO2 level at 637 ppm, followed by the variable air volume (VAV) systems with 664 ppm, and constant volume (CV) systems with a mean of 703 ppm. Schools with UV systems had the lowest mean air exchange rate at 2.67 air changes per hour (ACH), followed by the VAV system type at 2.80 ACH and the CV system type at 4.61 ACH. Indoor versus outdoor particle ratios were calculated for each ventilation system type. Particles with aerodynamic diameters ranging from 0.1-1.0 microm had a geometric mean ratio ranging from 0.38 to 0.68; particles with aerodynamic diameters ranging from 1-3 microm had ratios ranging from 1.39 to 5.47, and particles with aerodynamic diameters greater than 3 microm had ratios ranging from 3.20 to 14.76. Schools using VAV systems had a significantly lower prevalence of red and watery eyes while schools with UV systems had an elevated prevalence of nasal congestion, sore throat, headache, and dustiness complaints. This increased prevalence of complaints in buildings with UV systems may be due to the increased particulate levels.
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PMID:Perceptions of indoor air quality associated with ventilation system types in elementary schools. 1159 44

In recent years, there have been increasing complaints from cockpit crew, cabin crew, and passengers that the cabin air quality of commercial aircraft is deficient. A myriad of complaints including headache, fatigue, fever, and respiratory difficulties among many others have been registered, particularly by flight attendants on long-haul routes. There is also much concern today regarding the transmission of contagious disease inflight, particularly tuberculosis. The unanswered question is whether these complaints are really due to poor cabin air quality or to other factors inherent intlight such as lowered barometric pressure, hypoxia, low humidity, circadian dysynchrony, work/rest cycles, vibration, etc. This paper will review some aspects relevant to cabin air quality such as volatile organic compounds (VOCs), carbon dioxide (CO2), carbon monoxide (CO), ozone (O3), particulates, and microorganisms, as well as the cabin ventilation system, to discern possible causes and effects of illness contracted inflight. The paper will conclude with recommendations on how the issue of cabin air quality may be resolved.
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PMID:Cabin air quality: an overview. 1190 87

Interictal cerebrovascular reactivity and blood flow velocities were tested in 23 patients with migraine without aura and 10 age- and sex-matched healthy controls by using the breath holding index (BHI). The mean systolic, diastolic and mean velocities and pulsatility indices were not different in the controls and patients. The BHI was found to be significantly greater (P=0011) in the patients (1.64 +/- 0.33) compared with the controls (1.26 +/- 0.37), showing an exaggerated reactivity to hypercapnia in migraineurs. Reactivity to pCO2 theoretically depends on pre-existing arteriolar tone and thereby on baseline velocity. Our finding of similar blood flow velocities in controls and patients suggests that the underlying cause for this high reactivity may not be an increased vasotonus but an increased sensitivity to changes in blood CO2 levels.
Cephalalgia 2002 May
PMID:Exaggerated interictal cerebrovascular reactivity but normal blood flow velocities in migraine without aura. 1210 91

To investigate further the pharmacological mechanism of an anti-migraine drug, sumatriptan, a 5-HT1B/1D receptor agonist, we studied its effect on the cerebral circulation in seven anaesthetized rats, particularly during hypercapnia. After injection of 0.6 or 6.0 microg/kg sumatriptan succinate, no significant change in cerebral blood flow (CBF) was observed either in the striatum or in the parietal cortex. The increase in CBF both in the parietal cortex and the striatum during 5% CO2 inhalation was significantly less when sumatriptan succinate 6.0 microg/kg was injected. Sumatriptan appeared to have a vasoconstrictor effect on the relaxed vessels by CO2 inhalation. This mechanism might be attributable to vasoconstriction through activation of 5-HT1B receptors located in the vascular smooth muscle rather than 5-HT1B receptors in the vascular adventitia.
Cephalalgia 2002 Jul
PMID:Effects of sumatriptan on cerebral blood flow under normo- and hypercapnia in rats. 1213 47

Tanacetum parthenium (feverfew), is a well-known herb for the prophylactic treatment of migraine. The primary objective was to show a dose-response of a new stable extract (MIG-99) reproducibly manufactured with supercritical CO2 from feverfew (T. parthenium). Furthermore, the study should provide data on the safety and tolerability of MIG-99. In a randomized, double-blind, multicentre, controlled trial with an adaptive design, the clinical efficacy and safety of three dosages of MIG-99 (2.08 mg; 6.25 mg; 18.75 mg t.i.d.) were compared with placebo. The patients (n = 147) suffered from migraine with and without aura according to International Headache Society (IHS) criteria and were treated with one of the study medications for 12 weeks after a 4-week baseline period. The primary efficacy parameter was the number of migraine attacks during the last 28 days of the treatment period compared with baseline. Secondary endpoints were total and average duration and intensity of migraine attacks, mean duration of the single attack, number of days with accompanying migraine symptoms, number of days with inability to work due to migraine as well as type and amount of additionally taken medications for the treatment of migraine attacks. The design of the study included a pre-planned adaptive interim analysis for patients with at least four migraine attacks within the baseline period. With respect to the primary and secondary efficacy parameter, a statistically significant difference was not found between the overall and the confirmatory intention-to-treat (ITT) sample in the exploratorily analysed four treatment groups. The frequency of migraine attacks for the predefined confirmatory subgroup of patients (n = 49) with at least four migraine attacks during the baseline period decreased in a dose-dependent manner (P = 0.001). The highest absolute change of migraine attacks was observed under treatment with 6.25 mg t.i.d. (mean +/- SD = -1.8 +/- 1.5 per 28 days) compared with placebo (-0.3 +/- 1.9; P = 0.02). Overall, 52 of 147 (35%) patients reported at least one adverse event (AE). The incidence of AEs in the active treatment groups was similar to that in the placebo group, and no dose-related effect was observed in any safety parameter. MIG-99 failed to show a significant migraine prophylactic effect in general. Accordingly, in the ITT analysis a dose-response relationship could not be observed. MIG-99 was shown to be effective only in a small predefined subgroup of patients with at least four attacks during the 28-day baseline period where the most favourable benefit-risk ratio was observed with a dosage of three capsules of 6.25 mg MIG-99 extract per day. Because of the low number of patients, these findings need to be verified in a larger sample. The incidence of AEs was similar for all treatment groups.
Cephalalgia 2002 Sep
PMID:The efficacy and safety of Tanacetum parthenium (feverfew) in migraine prophylaxis--a double-blind, multicentre, randomized placebo-controlled dose-response study. 1223 May 94

In recent years, there have been increasing complaints from cockpit crew, cabin crew, and passengers that the cabin air quality of commercial aircraft is deficient. A myriad of complaints including headache, fatigue, fever, and respiratory difficulties among many others have been registered, particularly by flight attendants on long haul routes. There is also much concern today regarding the transmission of contagious disease inflight, particularly tuberculosis. The unanswered question is whether these complaints are really due to poor cabin air quality or to other factors inherent inflight such as lowered barometric pressure, hypoxia, low humidity, circadian dysynchrony, work/rest cycles, vibration etc. This paper will review some aspects relevant to cabin air quality such as carbon dioxide (CO2), carbon monoxide (CO), ozone (O3), particulates, and microorganisms as well as the cabin ventilation system to discern if there is a possible cause and effect of illness contracted inflight. The paper will conclude with recommendations on how the issue of cabin air quality may be resolved.
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PMID:Aircraft cabin air quality: an overview [correction of overvier]. 1271 25

The aim of the study was to evaluate the laser-induced suppression periods of the temporalis muscle in patients with tension-type headache, compared with the pattern of temporalis activity suppression induced by electrical stimulation. Fifteen patients with chronic and 10 with episodic tension-type headaches were selected. Suppression periods were recorded simultaneously from both temporalis muscles using both electrical stimuli and CO2-laser stimuli. A significant reduction in the later electrically induced suppression period was found in both tension-type headache groups. Laser stimulation induced a first suppression period (LSP1) with a latency of about 50 ms in all patients. The features of LSP1 were similar across groups. The LSP1 should correspond to the first suppression period induced by electrical stimulus, which is partly a nociceptive response, whereas the second period seemed negligibly linked with the activation of pain-related afferents, though probably their activation may contribute to increase the reflex duration and to emphasize abnormalities in tension-type headache.
Cephalalgia 2003 Jun
PMID:Nociceptive temporalis inhibitory reflexes evoked by CO2-laser stimulation in tension-type headache. 1278 Jul 66

This stratified cross-sectional epidemiological study included 1053 school children aged 13-17 years. All pupils filled in a questionnaire on building-related symptoms and other relevant health aspects. The following exposure measurements were carried out: room temperature, CO2 level, and relative humidity; building characteristics including mold infestation were assessed, and dust was collected from floors, air, and ventilation ducts during a working day. Dust was examined for endotoxin level, and cultivated for viable molds. We did not find a positive association between building-related symptoms and extent of moisture and mold growth in the school buildings. Five of eight building-related symptoms were significantly and positively associated with the concentration of colony forming units of molds in floor dust: eye irritation, throat irritation, headache, concentration problems, and dizziness. After adjusting for different potentially confounding factors in separate analyses of each symptom, the above-mentioned associations between molds in dust and symptoms were still present, except for concentration problems. However, in none of the analyses was mold exposure the strongest covariate, being secondary to either asthma, hay fever, recent airway infection, or psychosocial factors.
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PMID:Molds in floor dust and building-related symptoms in adolescent school children. 1475 47

Headache is common in Cerro de Pasco (CP), Peru (altitude 4338 m) and was present in all patients with chronic mountain sickness (CMS) in CP reported here. Forty-seven percent of inhabitants report headache. Twenty-four percent of men have migraine with aura, with an average of 65 attacks a year. We assessed vasoreactivity of the cerebral vessels to CO2 by rebreathing and to NO by the administration of isosorbite dinitrate (IDN), a nitric oxide (NO) donor, using transcranial Doppler ultrasound in the middle cerebral artery (MCA) in natives of CP, some of whom suffered from CMS. We repeated the measurements in Lima (altitude 150 m) in the same subjects within 24 h of arrival. Vasodilatation in the middle cerebral artery supply territory in response to CO2 and NO, both physiologic vasodilators, is defective in Andean natives at altitude and in the same subjects at sea level. Incapacitating migraine can occur with impaired cerebral vasoreactivity to physiologic vasodilators. We propose that susceptibility to migraine might depend in part on gene expression with consequent alterations of endothelial function.
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PMID:Cerebral vasoreactivity in Andeans and headache at sea level. 1505 Apr 45


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