Oxygen-derived free radicals contribute to neural stunning in the canine heart.

Oxygen-derived free radicals (ODFR) contribute to delayed recovery of myocardial function after brief ischemia. We examined the effect of ODFR scavengers on ischemia-induced dysfunction of cardiac sympathetic nerves. Mongrel dogs were anesthetized and instrumented for recording heart rate, arterial pressure, systolic wall thickening, and left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCX) flow velocities.

Responsiveness of non-IHS migraine and tension-type headache to sumatriptan.

In a long-term efficacy and safety study, 424 patients were treated with sumatriptan (6 mg sc) for 1,904 migraine attacks. The patients were diagnosed with migraine based on IHS criteria but individual migraine attacks treated in the study were physician diagnosed; not necessarily required to meet IHS criteria. A re-analysis of the treatment response to open label sumatriptan (6 mg sc) indicated that 43 patients had treated at least one migraine that fulfilled IHS criteria for tension-type headache.

Myogenic constriction of human coronary arterioles.

Myogenic constriction is an important mechanism of blood flow regulation; however, it has never been demonstrated in the human coronary circulation. We examined responses of human coronary resistance vessels in vitro to changes in intraluminal pressure and evaluated the role of protein kinase C (PKC). Microvessels (passive diameter 44-227 microns) were dissected from atrial appendages obtained during cardiac surgery and studied under conditions of zero flow.

Effects of glycosylated hemoglobin on vascular responses in vitro.

Unlabelled: Vascular responses to endothelium-dependent vasodilators are greatly impaired in vivo, while isolated blood vessels from animals with diabetes mellitus demonstrate less consistent degrees of impairment. Glycation of proteins, such as hemoglobin, has been implicated in the vascular abnormalities associated with diabetes.

Objective: The purpose of this study was to test the hypothesis that glycosylated hemoglobin is capable of reducing endothelium-dependent vasodilator responses, possibly explaining impaired dilation observed in vivo.

Protective role of nerve growth factor against postischemic dysfunction of sympathetic coronary innervation.

Background: Nerve growth factor (NGF) is produced rapidly in myocardium after brief myocardial ischemia. It contributes to the maintenance of neural integrity in several tissues. We examined the effect of exogenous and endogenous NGF on ischemia-induced dysfunction of cardiac sympathetic nerves.

Role of adenosine receptor subtypes in neural stunning of sympathetic coronary innervation.

Adenosine plays an important role in postischemic dysfunction of cardiac sympathetic nerves because exogenously infused adenosine produces and adenosine deaminase prevents "neural stunning." We examined whether adenosine acts via a specific receptor mechanism to produce neural stunning. Anesthetized dogs were treated with propranolol to attenuate increases in coronary flow due to adrenergic stimulation of myocardial metabolism.

Role of parabrachial nucleus in baroreflex-mediated coronary vasoconstriction.

Coronary vasoconstriction is a component of the baroreflex response to bilateral carotid occlusion. The central pathways responsible for this reflex constriction are incompletely understood, but previous studies show that activation of parabrachial nucleus (PBN) elicits coronary vasoconstriction and that PBN shares prominent anatomic connections with other central baroreflex centers, including the nucleus of the tractus solitarius. Therefore, we examined whether PBN plays a role in baroreflex mediated coronary constriction and whether cell bodies rather than fibers passing through this region are involved.

Efficacy and tolerability of subcutaneous sumatriptan administered using the IMITREX STATdose System.

The efficacy and tolerability of subcutaneous (SC) sumatriptan administered with the IMITREX (sumatriptan succinate) STATdose System, which circumvents the need for patients or health care professionals to handle a syringe, were evaluated in two randomized, double-masked, parallel-group, placebo-controlled, multicenter studies. In the clinic, 158 adults with migraine diagnosed according to International Headache Society criteria received SC sumatriptan (6 mg) or placebo delivered with the IMITREX STATdose System for treatment of a migraine attack. By 120 minutes after SC dosing, 73% and 79% of sumatriptan-treated patients, compared with 28% and 37% of placebo-treated patients in studies 1 and 2, respectively, experienced headache relief (a statistically significant difference).

Impact of sumatriptan on workplace productivity, nonwork activities, and health-related quality of life among hospital employees with migraine.

This prospective, open-label study evaluated the effects of subcutaneous sumatriptan versus usual therapy on workplace productivity, activity time outside of work, and health-related quality of life in 43 men or women who were hospital employees diagnosed with migraine according to international Headache Society criteria. Patients treated migraines with their usual therapy for 12 to 18 weeks followed by subcutaneous sumatriptan for 6 months. Health-related quality of life measurements obtained at baseline, after usual therapy, and after sumatriptan therapy included the Short Form-36 Health Survey and the Migraine-Specific Quality of Life Questionnaire.

Analgesic rebound headache in clinical practice: data from a physician survey.

Background: Frequent, excessive use of over-the-counter or prescription analgesics may lead to analgesic rebound headache. Little is known about the magnitude of the health problem posed by analgesic rebound headache, its epidemiology, the characteristics of analgesic rebound headache sufferers, or about physicians' approaches to treatment.

Methods: Four hundred seventy-three practitioners, who had previously expressed an interest in the treatment of headache, were mailed a questionnaire designed to capture information about the frequency and management of analgesic rebound headache and about the characteristics of analgesic rebound headache sufferers.

Improvements in health-related quality of life with sumatriptan treatment for migraine.

Background: The debilitating effects of migraine might be reduced in patients using an effective migraine medication. The serotonin (5HT1) receptor agonist sumatriptan has been shown in clinical trials to alleviate headache and associated symptoms in the majority of patients treated.

Methods: Three hundred forty-four (344) patients with migraine were allowed to treat an unlimited number of migraine attacks for up to 24 months with subcutaneous sumatriptan (6 mg).

Patient preferences for migraine therapy: subcutaneous sumatriptan compared with other medications.

Background: This study was conducted to identify, from the patient's perspective, the important attributes of a migraine therapy and to assess the performance of subcutaneous sumatriptan, aspirin, acetaminophen, and patients' usual therapies with respect to these attributes.

Methods: Six hundred forty-eight patients who had received subcutaneous sumatriptan (one or two doses, 6 mg per dose, for a single migraine episode) or placebo in a clinical trial completed questionnaires.

Results: According to patients, the four most important attributes of a migraine therapy are "how well it works," "how safe it is," "how fast it works," and "side effects.

Transmural regulation of myocardial perfusion by neuropeptide Y.

In vivo studies have shown that sympathetic nerve stimulation improves the transmural distribution of myocardial perfusion by increasing the endocardial/epicardial flow ratio; however, the mechanism of this effect is unknown. During nerve stimulation both norepinephrine (NE) and neuropeptide Y (NPY) are released, either or both of which may exert vasoconstrictor effects. The present studies were performed to examine the effects of these two cotransmitters on the transmural distribution of myocardial perfusion in a canine model.

Use of an indwelling catheter for examining cardiovascular responses to pericardial administration of bradykinin in rat.

Objective And Methods: Epicardial application of pharmacologic agonists has been used to study nociceptive and reflex responses to agents such as bradykinin. We utilized a model where intrapericardial bradykinin was administered in a closed-chest rat. The procedure allows for reproducible administration of microliter doses of pharmacologic agonists in both conscious and anesthetized animals.

Role of adenosine in postischemic dysfunction of coronary innervation.

We sought to determine the role of adenosine in the sustained but reversible decrease in cardiac neurotransmission that occurs after brief ischemia. Adult mongrel dogs were anesthetized and instrumented for measurements of heart rate, arterial pressure, and left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCX) flow velocities. Changes in coronary vascular resistance were measured during bilateral stimulation of the stellate ganglia.

Inhibition of nitric oxide synthesis augments centrally induced sympathetic coronary vasoconstriction in cats.

The principal effect of sympathetic activation on the coronary circulation is an alpha-adrenergic coronary vasoconstriction in the presence of beta-receptor blockade. Secondary effects include vasodilation due to beta-adrenoceptor stimulation and alpha 2-mediated release of endothelium-derived relaxing factor (EDRF) from the coronary vascular endothelium. We hypothesized that blockade of nitric oxide synthesis (nitro-L-arginine methyl ester, L-NAME) would augment coronary vasoconstriction to sympathetic stimulation as a result of a decrease in alpha 2-mediated EDRF release.

Detection of cardioembolic sources with echocardiography.

Cerebral ischemic events remain a common cause of morbidity and mortality in the United States. Although the majority of patients with strokes have cerebrovascular disease, up to 20% of stroke patients have a cardioembolic source, especially younger patients or those with associated cardiac disease. TTE offers limited potential for identifying a cardioembolic source.

Coronary vasoconstrictor pathway from anterior hypothalamus includes neurons in RVLM.

We have previously identified discrete brain sites [anterior (AHA) and lateral hypothalamus, periaqueductal gray, pontine parabrachial nucleus, lateral reticular formation, and rostral ventrolateral medulla (RVLM)] in the cat, in which electrical or chemical activation produces coronary vasoconstriction. This study examines whether the most rostral (AHA) and caudal (RVLM) of these sites are connected as part of a common pathway mediating coronary vasoconstriction. In chloralose-anesthetized cats, electrical stimulation in the AHA produced maximum increases in arterial pressure (41 +/- 10%) and coronary vascular resistance (28 +/- 9%).

Use of echocardiography in detecting cardiac sources of embolus.

Up to 20% of all ischemic strokes are felt to be the result of emboli from the heart. High resolution transthoracic (TTE) and transesophageal (TEE) echocardiography have been the principal diagnostic tools for detecting associated cardiac abnormalities and for guiding medical and surgical approaches to these patients. In addition to identifying the precise location and morphological characteristics of intracardiac masses, echocardiography has improved our ability to predict embolic potential of these masses.

Coronary vascular response to the cerebral ischemia reflex.

Most centrally mediated sympathoexcitatory reflexes produce increases in arterial pressure, heart rate, and peripheral vascular resistance, including coronary vasoconstriction. Cerebral ischemia also causes large increases in arterial pressure and peripheral vasoconstriction but with modest or variable changes in heart rate. To examine the effect of cerebral ischemia on coronary vascular resistance, we produced cerebral ischemia in 14 cats by occluding the right brachiocephalic and left subclavian arteries for 30 seconds.

Prediction of immediate ventricular arrhythmias after coronary artery ligation.

Objectives: Our aim was to test the hypothesis that increased beat to beat morphologic variations in the body surface electrocardiogram (ECG) are associated with fragmented diastolic electrical activity that appears after coronary artery ligation and to correlate the appearance of spontaneous ventricular fibrillation after coronary ligation with the magnitude of the ECG beat to beat variability.

Background: Unstable and variably delayed electrical activation precedes the development of ventricular fibrillation in dogs with acute ischemia. Detection of these highly variable low amplitude signals from the body surface is currently impossible.

Effect of brief myocardial ischemia on sympathetic coronary vasoconstriction.

The purpose of the present study was to determine whether sympathetic coronary vasoconstrictor responses are altered after brief ischemia and reperfusion. Adult mongrel dogs were anesthetized and instrumented for measurements of heart rate, arterial pressure, left ventricular pressure, left ventricular dP/dt, anterior myocardial wall thickening, and left circumflex coronary artery (LCX) and left anterior descending coronary artery (LAD) blood flow velocities. Changes in coronary vascular resistance were recorded during intravenous bolus doses of norepinephrine and bilateral electrical stimulation of the stellate ganglia.

Emotional impact on parents of transported babies. Considerations for meeting parents' needs.

The authors discuss the transport of critically ill newborns in relation to the psychological impact of attachment in pregnancy, transition to parenthood, and prenatal experience of a medical emergency. Interviews with parents and medical staff are included to provide an understanding of the experience from these perspectives. Considerations and recommendations are given for building an effective program to address the emotional needs of families of transported babies.

Healthcare resource and lost labour costs of migraine headache in the US.

Migraine headache is responsible for significantly more healthcare resource and lost labour costs than previously reported. Costs associated with migraine were assessed via a survey conducted in 940 patients, 70% of whom responded. All met the International Headache Society's diagnostic criteria for migraine and had participated in one of two multicentre, single-dose, parallel-group, randomised, placebo-controlled clinical trials designed to assess the efficacy of an anti-migraine compound.