Patent foramen ovale and migraine.

Migraine is a common neurological disorder with a great impact on the quality of life and social activities. The patent foramen ovale (PFO) is an intra-atrial right-to-left shunt with a prevalence of 25% in the general population. An increased prevalence is found in patients with migraine, especially in migraine with aura. Percutaneous PFO closure might decrease the prevalence of migraine. However, most of these observational studies were retrospective without a randomized design and the results need to be interpreted with caution. In this review we describe the association between PFO and migraine and the different pathophysiological hypotheses, which have been proposed to explain this relationship.     

Modulation of histamine release by rat peritoneal mast cells in a superfusion set-up.

A new method is presented for studying mediator release in isolated peritoneal cells of the rat. Using a superfusion technique, cells can be maintained in a continuously cleared medium. Cells were stimulated with antigen, compound 48/80 or A23187 to characterize this preparation. In addition, inhibitory effects of theophylline, isoprenaline and cromoglycate on compound 48/80-induced histamine release were studied. We conclude that superfusion is a valid alternative to study mediator release from isolated peritoneal cells.     

Nitratbehandlung

Organic nitrates are used for the treatment of angina pectoris symptoms, acute coronary syndrome and for acute and chronic heart insufficiency. In spite of the proven effectiveness of organic nitrates for acute cases, long-term therapy is limited by to the development of tolerance. Recent animal experiments, as well as clinical data, show that an endothelial dysfunction is also induced, a disquieting point, especially considering the negative prognostic impact of endothelial dysfunction. Due to these side effects, the published guidelines of the American Heart Association and the American College of Physicians do not recommend the use of long-term nitrates, such as mono- and dinitrate, for the treatment of stable angina pectoris. Rather, if good left ventricular function is present the calcium antagonist amlodipine should be used. In cases of appreciably reduced left ventricular function, there is a current discussion, based on the recently published A-HeFT study, as to whether a combination therapy with organic nitrates and the effective arteriole dilator hydralazine is beneficial for patients with severe heart insufficiency.     

Intensity-dependent regional cerebral blood flow during 1-Hz repetitive transcranial magnetic stimulation (rTMS) in healthy volunteers studied with H215O positron emission tomography: I. Effects of primary motor cortex rTMS.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) affects the excitability of the motor cortex and is thought to influence activity in other brain areas as well. We combined the administration of varying intensities of 1-Hz rTMS of the motor cortex with simultaneous positron emission tomography (PET) to delineate local and distant effects on brain activity. METHODS: Ten healthy subjects received 1-Hz rTMS to the optimal position over motor cortex (M1) for producing a twitch in the right hand at 80, 90, 100, 110, and 120% of the twitch threshold, while regional cerebral blood flow (rCBF) was measured using H(2)(15)O and PET. Repetitive transcranial magnetic stimulation (rTMS) was delivered in 75-pulse trains at each intensity every 10 min through a figure-eight coil. The regional relationship of stimulation intensity to normalized rCBF was assessed statistically. RESULTS: Intensity-dependent rCBF increases were produced under the M1 stimulation site in ipsilateral primary auditory cortex, contralateral cerebellum, and bilateral putamen, insula, and red nucleus. Intensity-dependent reductions in rCBF occurred in contralateral frontal and parietal cortices and bilateral anterior cingulate gyrus and occipital cortex. CONCLUSIONS: This study demonstrates that 1-Hz rTMS delivered to the primary motor cortex (M1) produces intensity-dependent increases in brain activity locally and has associated effects in distant sites with known connections to M1.     

Trichloroethylene and halothane inhibit uptake and metabolism of 5-hydroxytryptamine in rat lung slices

The effect of exposure to organic solvents on uptake and metabolism of 5-HT was studied in rat lung slices. It was found that under control conditions 5-HT was both taken up and metabolized to 5-HIAA. When halothane (35,000 ppm) or trichloroethylene (18,000 ppm) were equilibrated with the incubation medium the uptake of 5-HT decreased by approximately 50% after 30 min of incubation, and the production of 5-HIAA was inhibited by approximately 70% and 80%, respectively. The results are consistent with earlier studies using a much more elaborate technique, in which halothane and trichloroethylene were found to depress 5-HT uptake in isolated perfused rat lungs. Our results demonstrate that the simpler technique employing lung slices can also be used, to investigate factors affecting pulmonary uptake of endogenous amines, and, potentially, the uptake of other compounds as well.     

Computed tomography in gunshot wounds to the neck: Can we predict vascular injury?

The purpose of this study was to evaluate the ability of helical computed tomography (CT) to detect arterial injuries in gunshot wounds to the neck. In a blinded retrospective review, 54 helical CT scans of the cervical spine were evaluated for bullet/bone fragments, subcutaneous air, bullet path, hematoma, spine fractures, and pharyngoesophageal compromise. The distance of fragments to a major vessel was calculated. CT findings that correlated significantly with major arterial injury included the presence of fragments (bullet/bone) close to a major vessel (2.5 mm) and spine fractures. Visualizing fragments <5 mm from a vessel or a transcervical bullet trajectory predicted 12 of 13 major arterial injuries. We conclude that CT clearly depicts anatomic damage. Specific findings, such as the location of fragments and bullet trajectory adjacent to a vessel and spine fractures, indicate a higher probability of vascular damage, thus directing more definitive evaluation.