Imaging the brain and vascular reactions to headache treatments: a systematic review.

BACKGROUND: Neuroimaging studies have made an important contribution to our understanding of headache pathophysiology. This systematic review aims to provide a comprehensive overview and critical appraisal of mechanisms of actions of headache treatments and potential biomarkers of treatment response disclosed by imaging studies. MAIN BODY: We performed a systematic literature search on PubMed and Embase databases for imaging studies investigating central and vascular effects of pharmacological and non-pharmacological treatments used to abort and prevent headache attacks. Sixty-three studies were included in the final qualitative analysis. Of these, 54 investigated migraine patients, 4 cluster headache patients and 5 patients with medication overuse headache. Most studies used functional magnetic resonance imaging (MRI) (n = 33) or molecular imaging (n = 14). Eleven studies employed structural MRI and a few used arterial spin labeling (n = 3), magnetic resonance spectroscopy (n = 3) or magnetic resonance angiography (n = 2). Different imaging modalities were combined in eight studies. Despite of the variety of imaging approaches and results, some findings were consistent. This systematic review suggests that triptans may cross the blood-brain barrier to some extent, though perhaps not sufficiently to alter the intracranial cerebral blood flow. Acupuncture in migraine, neuromodulation in migraine and cluster headache patients, and medication withdrawal in patients with medication overuse headache could promote headache improvement by reverting headache-affected pain processing brain areas. Yet, there is currently no clear evidence for where each treatment acts, and no firm imaging predictors of efficacy. This is mainly due to a scarcity of studies and heterogeneous treatment schemes, study designs, subjects, and imaging techniques. In addition, most studies used small sample sizes and inadequate statistical approaches, which precludes generalizable conclusions. CONCLUSION: Several aspects of headache treatments remain to be elucidated using imaging approaches, such as how pharmacological preventive therapies work, whether treatment-related brain changes may influence therapy effectiveness, and imaging biomarkers of clinical response. In the future, well-designed studies with homogeneous study populations, adequate sample sizes and statistical approaches are needed.

The volitional travel speed varies with reproductive state in mature female brown trout Salmo trutta.

This study tested the effect of reproduction on the volitional travel speed of mature female brown trout Salmo trutta L. The downstream travel speed in the pre-spawning state was 0.25 m s(-1) (95% CI : 0.19, 0.34) while it increased significantly to 0.65 m s(-1) (95% CI: 0.49, 0.87) in the post-spawning state. The results suggest state-dependent travel speed in S. trutta.

Combining necrosis and platelet markers for perfecting myocardial infarction rule out: how close are we?

Each year, at least 5 million patients in the United States present to hospital emergency departments with the complaint of chest pain, and more than 10% of them will be diagnosed with acute myocardial infarction. One of the foremost tasks of the emergency department physician is to avoid unnecessary admissions and concomitantly to minimize the number of patients discharged home inappropriately. Currently available diagnostic tools, including the electrocardiogram and myocardial markers, have several shortcomings, including low specificity, and delayed sensitivity for the timely detection of myocardial necrosis. Therefore, the search for better methods of rapidly identifying patients with unstable coronary syndromes is one of the utmost priorities of modern emergency medicine. Available biochemical diagnostic tools are discussed in this review, focusing on the potential benefits of combining myocardial necrosis markers with indicators of platelet activation. It is hypothesized that such a combined approach may be more powerful in myocardial infarction risk stratification than separate marker determination.

Neutrophil elastase activity and superoxide production are diminished in neutrophils of alcoholics.

Several lines of evidence indicate that neutrophil elastase and oxidants secreted by phagocytic inflammatory cells play key roles in the development of centrilobular emphysema. A recent report suggests that ethanol consumption may have a protective role against this disease in smokers. The aim of this study was to examine the effect of ethanol consumption on neutrophil elastase activity and superoxide production of peripheral blood neutrophils. These activities were measured in neutrophils from 52 male intoxicated patients and compared to activities in neutrophils from 20 male volunteers. Neutrophils from intoxicated patients contained 31% less elastase activity than that found in controls, 0.99 +/- 0.27 versus 1.44 +/- 0.23 micrograms/10(6) neutrophils (p less than 0.0001) and produced 25 to 27% less superoxide than controls in response to phorbol 12-myristate-13-acetate, 0.90 +/- 0.17 versus 1.2 +/- 0.21 nmol/min/10(6) PMN (p less than 0.0001) or N-formylmethionylleucylphenylalanine, 0.64 +/- 0.19 versus 0.88 +/- 0.24 (p less than 0.001). In follow-up studies of 10 patients admitted for acute alcoholism, elastase activity and superoxide production remained low for 2 to 4 days. After 6 to 10 days, elastase activity and superoxide production were significantly greater than they were at Day 0 and approached normal levels. Neutrophils isolated from blood samples of healthy abstaining donors, which had been exposed to ethanol or to plasma from inebriated patients for 16 to 20 h, showed no loss of elastase activity or superoxide production.(ABSTRACT TRUNCATED AT 250 WORDS)