Sympathetic vasoconstriction not mediated by aoadrenoceptors has been identified in vitro and in animals but not in humans. We evaluated the effect of ciadrenoceptor blockade on either endogenous vascular sympathetic activation (obtained through the application of a nonhypotensive lower-body negative pressure, -10 mm Hg for 5 minutes) or selective postsynaptic aoadrenoceptor stimulation by exog...

In vitro data indicate that the activation of A2 adenosine receptors increases renin release by the accumulation of cyclic AMP. Because in human forearm vessels beta-adrenergic receptor stimulation causes the local release of renin and angiotensin II through the increase of cyclic AMP, we evaluated in six essential hypertensive subjects whether adenosine can release vascular angiotensin II. Ade...

Transcranial magnetic brain stimulation (TMS) was used to assess the influence of the corticospinal system on motor output during forearm unloading in humans. Unloading was obtained either "passively" by the experimenter, or "actively" with the subjects' own contralateral arm. Anticipatory postural adjustments consisted of changes in the activity of a forearm flexor muscle prior to active unloa...

OBJECTIVE Details on airbag injuries to the upper extremity are relatively unknown to clinicians. The injuries presented here should provide a clear understanding of the mechanisms of forearm, hand, and wrist injuries that may be seen by emergency room physicians. MATERIALS AND METHODS From our crash investigations of 325 airbag-equipped passenger cars, a subset of upper extremity injuries ar...

The measurement of humeral kinematics with a sensor on the humerus is susceptible to large errors due to skin motion artifacts. An alternative approach is to use data from a forearm sensor, combined with data from either a scapular or thoracic sensor. We used three tasks to assess the errors of these approaches: humeral elevation, elbow flexion and humeral internal rotation. Compared with the h...

Autonomic responses may underlie associations among anxiety, vestibular dysfunction, and unexplained syncope. Mental stress (MS), an anxiety-inducing stimulus, causes forearm vasodilation, whereas the vestibulosympathetic reflex (VSR) causes forearm vasoconstriction. The purpose of this study was to examine the combined effects of mental and vestibular stimulation on neurovascular control in th...

This study was designed to investigate the effects of L-arginine (the substrate of endothelium-derived nitric oxide) in human forearm vessels. We examined whether intra-arterial infusion of L-arginine dilated forearm vessels and augmented vasodilatory responses to acetylcholine in young, healthy humans. The left brachial artery was cannulated for drug infusions and direct measurement of arteria...

BACKGROUND Despite an increased propensity to primary failure in forearm arteriovenous fistulae compared with upper arm fistulae, forearm fistulae remain the preferred primary access type for chronic hemodialysis patients. In a high risk patient population with multiple medical comorbidities associated with requirement for intravenous access we compared the rates of access failure in forearm an...

BACKGROUND Plastic deformation of the forearm is a rare and frequently missed injury in adults that can result in a significant loss of forearm rotation. The condition is reported mainly in Western countries; however, it is not uncommon in Eastern developing countries. We conducted a retrospective study of 30 cases of forearm deformation to find common factors to increase awareness of the condi...