Beta-adrenergic vasodilator mechanism in the finger

Reevaluating the epinephrine myth: A comprehensive review

ABSTRACT

The combination of local anesthetic drugs with epinephrine has conventionally been contraindicated in acral regions due to concerns of potential necrosis caused by compromised blood flow. However, this belief has been challenged since 2001, when studies demonstrated the safety and effectiveness of the combination. This review aims to analyze reported cases of acral area necrosis following the use of local anesthesia with epinephrine since 2001. A thorough search was conducted on PubMed and Google Scholar using specific keywords to identify articles reporting acral area necrosis caused using local anesthesia and epinephrine. Our search yielded eight publications describing a total of 13 cases of ischemic events in acral areas. These cases involved finger necrosis (five cases), scrotal skin necrosis (two cases), and eyelid necrosis (six cases), following the injection of a combination of epinephrine and lignocaine. The majority of affected patients were female who underwent surgical intervention and reconstruction. The use of epinephrine in local anesthesia offers significant advantages and is generally safe for acral areas. However, the risk of necrosis cannot be entirely eliminated, particularly in patients with compromised vascular function. Adhering to proper guidelines and selecting suitable patients can help mitigate the risk. Phentolamine serves as a potential rescue agent if vascular compromise occurs. Precautionary measures must be taken when using this combination in high-risk patients.

The Hybrid Excess and Decay (HED) model: an automated approach to characterising changes in the photoplethysmography pulse waveform

Photoplethysmography offers a widely used, convenient and non-invasive approach to monitoring basic indices of cardiovascular function, such as heart rate and blood oxygenation. Systematic analysis of the shape of the waveform generated by photoplethysmography might be useful to extract estimates of several physiological and psychological factors influencing the waveform. Here, we developed a robust and automated method for such a systematic analysis across individuals and across different physiological and psychological contexts. We describe a psychophysiologically-relevant model, the Hybrid Excess and Decay (HED) model, which characterises pulse wave morphology in terms of three underlying pressure waves and a decay function. We present the theoretical and practical basis for the model and demonstrate its performance when applied to a pharmacological dataset of 105 participants receiving intravenous administrations of the sympathomimetic drug isoproterenol (isoprenaline). We show that these parameters capture photoplethysmography data with a high degree of precision and, moreover, are sensitive to experimentally-induced changes in interoceptive arousal within individuals. We conclude by discussing the possible value in using the HED model as a complement to standard measures of photoplethysmography signals.

New mechanism-based approaches to treating and evaluating the vasculopathy of scleroderma

PURPOSE OF REVIEW

Utilizing recent insight into the vasculopathy of scleroderma (SSc), the review will highlight new opportunities for evaluating and treating the disease by promoting stabilization and protection of the microvasculature.

RECENT FINDINGS

Endothelial junctional signaling initiated by vascular endothelial-cadherin (VE-cadherin) and Tie2 receptors, which are fundamental to promoting vascular health and stability, are disrupted in SSc. This would be expected to not only diminish their protective activity, but also increase pathological processes that are normally restrained by these signaling mediators, resulting in pathological changes in vascular function and structure. Indeed, key features of SSc vasculopathy, from the earliest signs of edema and puffy fingers to pathological disruption of hemodynamics, nutritional blood flow, capillary structure and angiogenesis are all consistent with this altered endothelial signaling. It also likely contributes to further progression of the disease including tissue fibrosis, and organ and tissue injury.

SUMMARY

Restoring protective endothelial junctional signaling should combat the vasculopathy of SSc and prevent further deterioration in vascular and organ function. Indeed, this type of targeted approach has achieved remarkable results in preclinical models for other diseases. Furthermore, tracking this endothelial junctional signaling, for example by assessing vascular permeability, should facilitate insight into disease progression and its response to therapy.

Raynaud's phenomenon and related vasospastic disorders

Raynaud's phenomenon, which is characterized by episodic digital pallor, cyanosis and rubor upon exposure to cold environment or to stress, is relatively common, although the prevalence depends on the climate. Still, it is under-diagnosed, under-treated, and often confused with other conditions. Primary Raynaud's phenomenon (i.e., Raynaud disease) must be distinguished from secondary Raynaud's phenomenon (i.e., Raynaud syndrome) as long-term morbidity and outcomes differ vastly between the two conditions. Additionally, the practitioner must differentiate between Raynaud's phenomenon and related vascular disorders, such as acrocyanosis, pernio, and livedo reticularis. In this article, we review differences between the conditions and suggest an approach to diagnosis and treatment strategy for these disorders.

Cardiovascular autonomic reflex function after bilateral cardiac sympathetic denervation for ventricular arrhythmias

BACKGROUND

Bilateral cardiac sympathetic denervation (BCSD) is an effective therapy for ventricular arrhythmias (VAs) in cardiomyopathies (CMPs). After BCSD, residual autonomic nervous system (ANS) function is unknown.

OBJECTIVE

The purpose of this study was to assess ANS responses in patients with CMP before and after BCSD as compared with demographically matched healthy controls.

METHODS

Patients with CMP undergoing BCSD and matched healthy controls were recruited. Noninvasive measures-finger cuff beat-to-beat blood pressure (BP), electrocardiography, palmar electrodermal activity (EDA), and finger pulse volume (FPV)-were obtained at rest and during autonomic stressors-posture change, handgrip, and mental stress. Maximal as well as specific responses to stressors were compared.

RESULTS

Eighteen patients with CMP (mean age 54 ± 14 years; 16 men, 89%; left ventricular ejection fraction 36% ± 14%) with refractory VAs and 8 matched healthy controls were studied; 9 patients with CMP underwent testing before and after (median 28 days) BCSD, with comparable ongoing medication. Before BCSD, patients with CMP (n = 13) had lower resting systolic BP and FPV than did healthy controls (P < .01). Maximal FPV and systolic BP reflex responses, expressed as percent change were similar, while diastolic BP, mean BP, and EDA responses were blunted. After BCSD, resting measurements were unchanged relative to presurgical baseline (n = 9). EDA responses to stressors were abolished, confirming BCSD, while maximal FPV and BP responses were preserved. Diastolic BP, mean BP, and FPV responses to orthostatic challenge pointed toward a better tolerance of active standing after BCSD as compared with before. Responses to other stressors remained unchanged.

CONCLUSION

Patients with CMP and refractory VAs on optimal medical therapy have detectable but blunted adrenergic responses, which are not disrupted by BCSD.

A Review of Emotion Recognition Using Physiological Signals

Emotion recognition based on physiological signals has been a hot topic and applied in many areas such as safe driving, health care and social security. In this paper, we present a comprehensive review on physiological signal-based emotion recognition, including emotion models, emotion elicitation methods, the published emotional physiological datasets, features, classifiers, and the whole framework for emotion recognition based on the physiological signals. A summary and comparation among the recent studies has been conducted, which reveals the current existing problems and the future work has been discussed.

Development of noninvasive measurement of peripheral circulation and its medical application

Surveys were carried out on tissue blood flow measurement based on the thermal diffusion method and on the assessment of peripheral circulatory function using photosensors.Regarding the thermal diffusion method, first noninvasive measurement using a Peltier stack was carried out. Then, measurements using a thermal clearance curve at various temperatures were performed.For noninvasive measurement of the mechanical properties of peripheral arteries using photosensors, the author determined the vascular volume ratio and/or the relative vascular volume.For clinical application in field studies, it is necessary to develop an apparatus with which absolute evaluation of the intravascular volume can be carried out using the blood volume around the unit volume as an indicator. Therefore, an apparatus that removes a signal constituent from tissue other than the blood using two-wavelength photosensors is required.If a noninvasive method to accurately measure the intravascular volume is established, changes in the mechanical properties of the peripheral arteries that correspond to functional and organic changes in the normal response can be observed more directly. Moreover, quantitative assessment of peripheral circulatory function will become possible, and diagnosis of the severity of peripheral circulatory disorders will be facilitated.

Autonomic nervous system activity in emotion: a review

Autonomic nervous system (ANS) activity is viewed as a major component of the emotion response in many recent theories of emotion. Positions on the degree of specificity of ANS activation in emotion, however, greatly diverge, ranging from undifferentiated arousal, over acknowledgment of strong response idiosyncrasies, to highly specific predictions of autonomic response patterns for certain emotions. A review of 134 publications that report experimental investigations of emotional effects on peripheral physiological responding in healthy individuals suggests considerable ANS response specificity in emotion when considering subtypes of distinct emotions. The importance of sound terminology of investigated affective states as well as of choice of physiological measures in assessing ANS reactivity is discussed.

Autonomic neuropathy and toe circulation. A prospective study

Ankle and toe pressure ratios and toe temperature reactions to cold followed by indirect heating were evaluated in 23 diabetic patients with and without autonomic neuropathy (AN) in a first and in a second follow-up study after 5-7 years. In the first study, despite normal blood pressure ratios, AN patients, all with parasympathetic neuropathy, showed a markedly delayed increase in toe temperature after cooling followed by indirect heating. In the second study, most AN patients showed sympathetic neuropathy and had higher toe temperatures before cooling than those without AN. Parasympathetic neuropathy leads to increased sensitivity to cold in toe vessels and sympathetic neuropathy to vasodilation and increased toe temperatures.

Influence of autonomic neuropathy on leg circulation and toe temperature in diabetes mellitus

The relationship between neuropathy and peripheral circulation was assessed in 26 patients with a short to moderate duration (less than 20 years, mean 11 years) and in 26 patients with a long duration (greater than 20 years, mean 35 years) of diabetes mellitus. Peripheral nervous function was evaluated from measurements of vibration thresholds and ankle reflexes and autonomic nervous function from deep breathing, Valsalva, and tilt table tests. Peripheral circulatory tests included plethysmography, systolic blood pressure ratios, and thermography. A markedly delayed toe temperature increase after cooling followed by indirect heating occurred in diabetics of short duration with autonomic neuropathy (AN). Judging from blood flows and pressure ratios, functional vasospasm caused abnormal toe temperature reactions in short duration diabetics. No correlation existed between AN and abnormal toe temperature reactions in diabetics of long duration. Macroangiopathy rather than AN seemed to be responsible for abnormal toe temperature reactions in long duration diabetics. Thus, an abnormal toe temperature reaction indicates AN in patients with a short duration and macroangiopathy in patients with a long duration of diabetes.

Digital anesthesia with epinephrine: an old myth revisited

BACKGROUND

The prohibition against the use epinephrine with local anesthetics for digital blocks or infiltrative anesthesia is an established dogma in dermatologic surgery. Major textbooks reinforce this teaching suggesting that there is substantial risk of digital gangrene caused by local anesthesia containing epinephrine.

OBJECTIVE

To provide a comprehensive literature review of the cases of digital necrosis associated with the use of local anesthesia containing epinephrine.

METHODS

A PubMed search of the National Library of Medicine database using the terms "lidocaine" and "epinephrine" and "finger" with no specified limits was performed.

RESULTS

A total of 16 papers were referenced and only 6 papers dealt with digital anesthesia. A total of 50 cases of digital gangrene were reported, mostly in the early part of the 20th century. In 21 cases digital gangrene was associated with anesthetic mixed with epinephrine. Actual concentration of epinephrine was known in only 4 cases. Careful analysis of all cases of necrosis did not support epinephrine itself as a cause. Other contributing factors including older compounds (cocaine, eukaine, and procaine), non-standardized inaccurate methods of mixing epinephrine with lidocaine, inappropriate use of a tourniquet, postoperative hot soaks, infection, or large anesthetic volume were also present. None of the reported cases were associated with the use of a commercial lidocaine-epinephrine mixture.

CONCLUSION

A literature review failed to provide evidence to support the dogma that block or infiltrative anesthesia with lidocaine and epinephrine produces digital necrosis. Proper injection technique and adequate selection of patients (absence of thrombotic, vasospastic conditions, or uncontrolled hypertension) are mandatory to minimize complications. The addition of epinephrine, in fact, reduces the need for the use of tourniquets and large volumes of anesthetic and provides better and longer pain control during digital procedures.

Development of a multi-channel exploratory battery for psychophysiological assessment: the Stress Profile

OBJECTIVE

As the expanding field of psychophysiology is currently demanding applied methodologies to be used in the clinic, this study aimed to develop a practical multi-channel exploratory battery for psychophysiological evaluation of stress (the Psychophysiological Stress Profile; PSP). The PSP records 6 psychophysiological variables and it is designed to be mainly used in the daily clinic. Moreover, the PSP was intended to be 'the method' to obtain normative and individual psychophysiological patterns, providing relevant information for the therapeutic process.

METHODS

Two hundred and three subjects were evaluated with the PSP in two different contexts: the natural environment and the laboratory. Factorial analysis was applied to obtain psychophysiological profiles. These profiles are based on the covariation among different system responses. The Burt and Tucker Congruence Coefficient was used to compare factorial structures.

RESULTS

A 3-factor structure was obtained in both contexts, Congruence Coefficient indicates that these factorial structures are very similar, indicating the existence of a unique and consistent psychophysiological pattern that characterizes the sample.

CONCLUSIONS

The identified factorial structure shows relevant activation patterns, offering a comprehensive view of the subject's functioning. The structure is consistent through samples and can be considered as normative data for the studied population. PSP has turned out to be a quick and easy-to-use psychophysiological battery that has shown adequate internal consistency for all the recorded variables. In this way, the PSP methodology shows its practical value and usefulness in the assessment process.

Finger plethysmography--a method for monitoring finger blood flow during sleep disordered breathing

We investigated a non-invasive measurement for changes in finger blood flow during wakefulness and sleep. Changes in finger blood flow, reflected by pulse wave amplitude (PWA) derived from finger plethysmography, were compared with changes in forearm vascular flow assessed by venous occlusion plethysmography after intra-arterial infusion of norepinephrine (NE), phentolamine, and isoproterenol (n=15, 15, 14 subjects, respectively). Moreover, PWA was assessed during obstructive breathing during sleep (n=8 patients). Vasoconstriction in the finger (PWA) was stronger than that obtained in the forearm vascular bed in the higher NE dose range both without (ANOVA, P=0.002) and with concomitant phentolamine-induced alpha-receptor blockade (P=0.02). Isoproterenol increased forearm blood flow but did not induce flow changes detectable by the finger plethysmographic technique (P<0.001). PWA was significantly reduced during arousal from obstructive sleep apnea (-37.5+/-16.1%, P=0.002, n=6 patients), suggesting vasoconstriction in the digital vascular bed. PWA derived from finger plethysmography allows continuous, non-invasive measurement of changes in finger blood flow during wakefulness and sleep. However, as may be expected from the anatomical and functional differences between the finger and forearm vascular beds and demonstrated by the lack of response to beta(2)-receptor stimulation, PWA does not mimic forearm vascular flow characteristics. Thus, finger plethysmography may be a useful complement to current vascular research techniques, in particular to monitor sympathetic influences on skin blood flow in the finger.

Gender differences in sensitivity to adrenergic agonists of forearm resistance vasculature

OBJECTIVES

The goal of this study was to investigate the mechanism of reduced vasoconstrictor sensitivity to norepinephrine in women compared with men.

BACKGROUND

beta2-adrenergic agonists such as albuterol dilate forearm resistance vessels, partly by activating the L-arginine/nitric oxide pathway. Norepinephrine (which acts as beta- as well as alpha-adrenergic receptors) causes less forearm vasoconstriction in women than it does in men. This could be explained by a greater sensitivity to beta2-receptor stimulation in women than in men.

METHODS

Forearm blood flow was measured by venous occlusion plethysmography in healthy women (days 10 to 14 of the menstrual cycle) and in men. Drugs were administered via the brachial artery in three separate protocols: albuterol +/- NG-monomethyl-L-arginine (an inhibitor of nitric oxide synthase); substance P, nitroprusside and verapamil (control vasodilators); norepinephrine (+/- propranolol, a beta-adrenergic receptor antagonist).

RESULTS

Vasodilator responses to albuterol were greater in women than they were in men (p = 0.02 by analysis of variance). NG-monomethyl-L-arginine reduced these similarly in men and women. Responses to control vasodilators were less in women than they were in men (each p < 0.05). Norepinephrine caused less vasoconstriction in women than it did in men (p = 0.02). Propranolol did not influence basal flow in either gender nor responses of men to norepinephrine but increased vasoconstriction to each dose of norepinephrine in women (p < 0.0001 for interaction between gender and propranolol). Responses to norepinephrine coinfused with propranolol were similar in men and women.

CONCLUSIONS

Stimulation of beta2-adrenergic receptors causes greater forearm vasodilation in premenopausal women, at midmenstrual cycle, than it does in men. This is sufficient to explain why vasoconstriction to brachial artery norepinephrine is attenuated in such women.

Pharmacological evidence that alpha1-and alpha2-adrenoceptors mediate vasoconstriction of carotid arteriovenous anastomoses in anaesthetized pigs

Vasoconstriction of carotid arteriovenous anastomoses may be involved in the therapeutic action of acutely acting anti-migraine agents, including the triptans and ergot alkaloids. While 5-HT1B/1D receptors mediate the effect of triptans, ergotamine and dihydroergotamine also interact with alpha-adrenoceptors. In the present study, we investigated the potential role of alpha1- and alpha2-adrenoceptors in mediating vasoconstriction of carotid arteriovenous anastomoses in anaesthetized pigs. Ten minute intracarotid infusions of phenylephrine (1, 3 and 10 microg kg(-1) min(-1)) or BHT 933 (3, 10 and 30 microg kg(-1) min(-1)) produced dose-dependent decreases in total carotid and arteriovenous anastomotic conductances; no changes were observed in the capillary fraction. The carotid vascular effects of phenylephrine and BHT 933 were selectively abolished by prazosin (100 microg kg(-1), i.v.) and rauwolscine (300 microg kg(-1), i.v.), respectively. The responses to phenylephrine and BHT 933 were not affected by the selective 5-HT1B/1D receptor antagonist GR127935 (500 microg kg(-1), i.v.). These results show that both alpha1- and alpha2-adrenoceptors can mediate vasoconstriction of carotid arteriovenous anastomoses in anaesthetized pigs. Since vasoconstrictor activity in this in vivo model is predictive of anti-migraine activity, an agonist activity at particularly the alpha2-adrenoceptor subtypes, in view of their less ubiquitous nature, could provide migraine abortive potential. Thus, the present results may aid further understanding of the mode of action of some current anti-migraine agents and may eventually be helpful in the development of future treatment in migraine.

Use of subcutaneous terbutaline to reverse peripheral ischemia

Four cases are presented, one involving extravasation of a dopamine and dobutamine solution in the arm and three involving accidental digital injection of epinephrine into the thumb. In three cases, local infiltration of terbutaline resulted in dramatic reversal of vasospasm and ischemia. In the remaining case the use of terbutaline resulted in minor clinical improvement. These are the first reported cases involving the successful treatment of peripheral ischemia with subcutaneous terbutaline. This experience suggests that terbutaline may be an effective alternative for treatment of peripheral ischemia when phentolamine is not available.

Assessing microcirculation in familial dysautonomia by laser Doppler flowmeter

Microcirculatory vasomotor responses to an alpha-adrenergic agonist and an antagonist were assessed in 11 familial dysautonomia and nine control subjects by laser Doppler flowmetry. Using two iontophoresis machines, blood flow in the midclavicular areas was continuously monitored by two channel laser Doppler flowmeter. Simultaneously, the alpha-antagonist (0.5 mM phentolamine hydrochloride) and a control solution (0.9% saline) were iontophoresed at 200 microA for 15 min. The alpha-agonist (0.5 mM norepinephrine bitartrate) was then iontophoresed (20 microA) to both pretreated areas for progressively longer pulses separated by 3-min observation intervals (15, 30, 60, 90, 120 s). The familial dysautonomia subject group had higher mean baseline perfusion with widely fluctuating baselines, especially on the phentolamine pretreated side (P = 0.03). Saline iontophoresis significantly increased perfusion in the control group, but not in the familial dysautonomia group (ANOVA: P = 0.02 and 0.15, respectively). There was > 100% increase in flow by the end of the saline observation period in seven of nine controls, but in only three of 11 familial dysautonomia subjects. Phentolamine iontophoresis differentiated familial dysautonomia subjects into responders and nonresponders by 7-8 min when all nine control subjects, but only five of 11 familial dysautonomia subjects, had > 200% increase in blood flow. Irrespective of pretreatment type, norepinephrine decreased blood flow in both familial dysautonomia and control groups (ANOVA: P < 0.0001), but the final mean change after saline was greater in the control group, P = 0.02. The final mean changes of flow after phentolamine pretreatment were not different between the two groups and were comparable to the familial dysautonomia group's smaller response after saline pretreatment. Higher baseline perfusion suggests dilation may be intrinsic to familial dysautonomia vasculature. Two populations of familial dysautonomia subjects are noted; those who like controls increase blood flow with iontophoresis of the alpha-antagonist and those who are refractory. In addition, in familial dysautonomia subjects, the microcirculatory constrictive response to alpha-agonist iontophoresis is less than that observed for controls. These data suggest that some familial dysautonomia subjects may have decreased or dysfunctional adrenoceptors as well as decreased innervation.

The effect of adrenergic blockade on blushing and facial flushing

The effect of adrenergic blockade on vascular responses in the forehead was assessed during stressful mental arithmetic, singing, and moderate exercise in 21 frequent blushers and 21 infrequent blushers. Adrenergic antagonists were introduced into a small site on the forehead by iontophoresis, and vascular responses were monitored bilaterally with laser Doppler flowmetry. Beta blockade prevented increases in blood flow in infrequent blushers during mental arithmetic and partially inhibited vasodilatation during singing, indicating minor participation of beta-adrenoceptors in blushing. Alpha blockade did not affect blushing but augmented vasodilatation during exercise. Despite higher ratings of self-consciousness in frequent than in infrequent blushers, vascular responses were similar in both groups. Thus, blushing propensity does not appear to be related to the density of alpha- or beta-adrenoceptors in facial vessels and may have a psychological basis.

Racial and gender effects on the relaxation response: implications for the development of hypertension

This study was designed to explore the effect of race and gender on the forehead muscle tension and finger temperature response to biofeedback-assisted relaxation training in individuals with normal blood pressure. Forty-five subjects-18 Black and 27 White, 25 males and 20 females-participated in eight sessions of autogenic relaxation training and thermal biofeedback. Multivariate analysis of variance of the variables measured at baseline (systolic BP diastolic BP sodium excretion, anxiety) was significant for gender Univariate analysis showed males different from females in DBP Na(+) excretion, and trait anxiety. Pretest values of muscle tension were similar by gender, but pretest temperatures were lower in males than females. Repeated measures ANOVA for muscle tension showed a significant effect of period. For temperature a significant effect of period, gender and gender x period was observed. Males increased temperature more than females. There was no effect of history of hypertension on the relaxation response. Multiple regression performed on change in muscle tension and change in temperature showed that pretest muscle tension predicted change in muscle tension. Four variables contributed to the variance in change in temperature: pretest temperature, sodium excretion, and state and trait anxiety.

Adrenergic receptors in the forehead microcirculation

The presence of alpha- and beta-adrenoceptors in the forehead microcirculation was investigated in 49 healthy subjects. Local vascular responses to noradrenaline, isoprenaline and adrenergic antagonists, administered transcutaneously by iontophoresis, were monitored via laser Doppler flowmetry. Iontophoresis of the alpha-adrenergic antagonist phentolamine induced a persistent increase in skin blood flow, whereas iontophoresis of saline induced a minor increase in skin blood flow which subsided rapidly. Skin blood flow increased moderately after the iontophoresis of the beta-adrenergic antagonist propranolol. Pretreatment of the experimental site with phentolamine blocked the normal vasoconstrictor response to noradrenaline, and unmasked a minor vasodilator component of response in some subjects. Iontophoresis of the beta-adrenergic agonist isoprenaline induced dose-dependent vasodilatation which was antagonised by propranolol. These findings indicate that alpha-adrenoceptors in the forehead microcirculation normally mediate a vasoconstrictor response to iontophoretically-applied noradrenaline. In addition, beta-adrenoceptors appear to mediate a minor vasodilator component of response.

Physiological problems of biofeedback control of the pulse rate

Data are presented in this article on the voluntary control of the heart rate in man as a function of individual typological differences in adaptive attributes, in the ecological features of the milieu of habitation and work, as well as in the presence of deviations in the state of health (neuroses, vegetovascular dystonias, etc.). The key significance of training of the rhythmic regulatory processes in the course of biofeedback control is substantiated.

Raynaud's syndrome, an enigma after 130 years

The recent literature concerning Raynaud's syndrome is reviewed. Raynaud's syndrome is as common as hypertension and diabetes. In spite of its generally benign character, it causes a lot of discomfort to individuals and sickness absenteeism to society, especially in the colder regions of the world. The etiology remains an enigma 130 years after its first description, perhaps even more so than ever before, the many new theories proposed in the literature. Clearly, in a condition where seventy different etiologic theories are advocated, the culprit lesion is obviously missing, or there is not a culprit lesion but an accumulation of conditions having nothing in common but a few symptoms. Moreover a Raynaud attack may result, not from a single event, but from a cascade of events, just as, for example, hemostasis does. Controversy about diagnosis exists all over. For example, how does one make a diagnosis? Patient history has been considered unreliable. A standardized cold test, though highly reproducible in the authors' hands, is far from common property. Raynaud's syndrome is a condition for which thirty-eight therapies have been advocated in the last three years, but the curative answer is still to come.

Effects of tertatolol, a beta-adrenoceptor antagonist with agonist affinity at 5-HT1A receptors, in an animal model of migraine: comparison with propranolol and pindolol

Constriction of carotid arteriovenous anastomoses is a common property of several antimigraine drugs. The present study concerns the effects of tertatolol (0.1, 0.3, 1 and 3 mg/kg i.v.), a novel beta-adrenoceptor antagonist with an agonist action on 5-HT1A receptors, on systemic haemodynamics and carotid blood flow distribution in the anaesthetized pig. Two other beta-adrenoceptor antagonists, one (propranolol) with and one (pindolol) without antimigraine actions, were compared (doses: 0.03, 0.1, 0.3 and 1 mg/kg i.v.) with tertatolol in this animal experimental model of migraine. While the beta-adrenoceptor antagonist with partial agonist action, pindolol, increased heart rate and cardiac output, propranolol and tertatolol decreased these variables moderately. Mean arterial blood pressure also decreased with the two highest doses of propranolol and with the highest dose of tertatolol. The calculated total peripheral conductance decreased with the first three doses of tertatolol. Carotid haemodynamic variables were not affected by pindolol, except for some increase in the nutrient fraction after the highest dose. Propranolol and especially tertatolol decreased both total carotid blood flow and arteriovenous anastomotic blood flow without affecting the nutrient fraction. In the case of tertatolol, blood flow decreases were accompanied by similar decreases in vascular conductance, indicating active arteriovenous anastomotic constriction. It is therefore suggested that tertatolol may prove effective in the treatment of migraine.

Beta 2-adrenoceptor density in fibroblast culture correlates with human NaCl sensitivity

To study salt sensitivity in humans and its relation to expression of adrenoceptors, 20 male normotensive Caucasians were investigated on a diet of 180 mmol NaCl/day followed by 60 mmol NaCl/day over 2 wk and again by 180 mmol NaCl/day over 2 wk, and blood pressure changes were assessed by long-term oscillatory blood pressure monitoring under basal conditions. Individual cell cultures of skin fibroblasts from skin biopsies were also established, and alpha 2- and beta 2-adrenoceptors were measured. Seven subjects were salt sensitive, and the remainder were salt resistant. Cultured skin fibroblasts in salt-sensitive subjects express less than half the number of beta 2-adrenoceptors compared with salt-resistant subjects (65 +/- 12.7 vs. 173 +/- 14.8 fmol/mg, P less than 0.001), and there is a correlation between the absolute rise of blood pressure on a high-salt diet and the density of beta 2-adrenoceptors (r = -0.67, P less than 0.01). It remains to be established whether a reduced in vitro density of beta 2-adrenoceptors in cultured cells is causally related to salt sensitivity in normotensive humans.

Finger blood pressure and rewarming rate for screening and diagnosis of Raynaud's phenomenon in workers exposed to vibration

Both the finger systolic blood pressure (FSP) and the rewarming test of finger skin are measures of circulation in the finger; the first reflects the vasoconstriction phase and the second the vasodilatation phase. The combinations of the specificity and the sensitivity of these methods were evaluated by a receiver operating characteristic curve (ROC). The material included 37 vibration-induced white finger (VWF) cases, five primary Raynaud's cases, and 37 controls. The specificity of the FSP test was high with regard to the anamnesis of white finger and the test was useful for the diagnosis of Raynaud's phenomenon, but the sensitivity was too low for screening. The rewarming test was useful for screening primary Raynaud's case and possibly for screening disorders in peripheral vasodilative function. The connections between the rewarming test and VWF are not clear and according to the present study the rewarming test was not suitable for screening VWF.

Physiological mechanisms of temperature biofeedback

Research on the physiological mechanisms of finger temperature biofeedback with normal subjects and Raynaud's disease patients is reviewed. Studies conducted in the author's laboratory have shown that feedback-induced vasodilation is mediated through a non-neural, beta-adrenergic mechanism rather than through reductions in sympathetic nervous system activation. In contrast, feedback-induced vasoconstriction is mediated through the traditional, sympathetic nervous pathway. When used with primary Raynaud's disease patients, feedback-induced vasodilation has achieved reductions in reported symptom frequency ranging from 66% to 92% in controlled investigations. Future research directions are discussed.

Transfer of training of the biofeedback-assisted control of hand temperature

This study examined the effect of prior biofeedback-assisted training of hand warming or hand cooling on the subsequent ability to train the opposite response. A two-group crossover design employed 43 subjects with one group receiving three days of hand warming followed by three days of hand cooling, while the second group received the opposite sequence. Analysis indicated subjects were able to produce the appropriate changes in hand temperature and were more successful at hand cooling than hand warming. During the transfer of training phase, subjects with prior training in hand cooling were able to produce warming above baseline levels compared with subjects initially trained to hand warm. In contrast, prior training of hand warming had no effect on the subsequent ability to cool hands.

Pharmacological versus non-pharmacological prophylaxis of recurrent migraine headache: a meta-analytic review of clinical trials

In order to generate information about the relative effectiveness of the most widely used pharmacological and non-pharmacological interventions for the prophylaxis of recurrent migraine (i.e., propranolol HCl and combined relaxation/thermal biofeedback training), meta-analysis was used to integrate results from 25 clinical trials evaluating the effectiveness of propranolol and 35 clinical trials evaluating the effectiveness of relaxation/biofeedback training (2445 patients, collectively). Meta-analysis revealed substantial, but very similar improvements have been obtained with propranolol and with relaxation/biofeedback training. When daily recordings have been used to assess treatment outcome, both propranolol and relaxation/biofeedback have yielded a 43% reduction in migraine headache activity in the average patient. When improvements have been assessed using other outcome measures (e.g., physician/therapist ratings), improvements observed with each treatment have been about 20% greater. In both cases, improvements observed with propranolol and relaxation/biofeedback have been significantly larger than improvement observed with placebo medication (14% reduction) or in untreated patients (no reduction). Meta-analysis thus revealed substantial empirical support for the effectiveness of both propranolol and relaxation/biofeedback training, but revealed no support for the contention that the two treatments differ in effectiveness. These results suggest that greater attention should be paid to determining the relative costs and benefits of widely used pharmacological and non-pharmacological treatments.

Use of isolated cold stress testing in determining normal lower extremity thermoregulation

Isolated cold stress testing was performed on 72 healthy subjects in order to evaluate the normal thermoregulatory potential of vessel beds in the acral areas of the lower extremity. Two patterns of response were demonstrated: a cool response in approximately 80% of subjects, and a warm pattern in approximately 20%. In the former, the responses to cold stress were more active and the temperatures lower; in the latter, there was little change in temperature in response to the cold stress. Both patterns correlated strongly with initial temperature, and neither pattern correlated with age, sex, or smoking habits. No subjects reported pain, numbness, or discomfort during the test. This study demonstrated that wide variations in thermoregulatory flow were possible without clinical symptoms, and suggested that nutritional blood flow was adequate to meet metabolic demands despite thermoregulatory modulation.

Quantitative measurements of finger blood flow during behavioral treatments for Raynaud's disease

Quantitative measurements of finger blood flow have not been performed during temperature biofeedback or other treatments for Raynaud's disease. In the present investigation, finger blood flow was determined with venous occlusion plethysmography, in addition to measurements of finger temperature, heart rate, blood pressure, and skin conductance level. After a maximum vasodilation test, subjects received 10 sessions of finger temperature biofeedback or autogenic training. There were no group differences during the maximum vasodilation test. During training, temperature feedback subjects showed significant elevations in finger blood flow, finger temperature, and skin conductance level, whereas those who received autogenic training did not. These findings could not be explained by group differences in other cardiovascular measures and are consistent with previous studies suggesting the involvement of an active vasodilating mechanism in temperature feedback.

Inverse regulation of alpha-2 and beta-2 adrenoceptors in salt-sensitive hypertension: an hypothesis

A high salt diet leads to up-regulation of alpha-2 adrenoceptors and down-regulation of beta-2 adrenoceptors in normotensive subjects. Although the increase in blood pressure with a high salt diet is not related to the magnitude of the alpha-2 or beta-2 adrenoceptor changes alone, it is related to the increase in the ratio of the receptor changes (operative alpha/beta adrenoceptor ratio). An increase in the operative alpha/beta adrenoceptor ratio with a high salt intake results in vasoconstriction and reduced vasodilatation at resistance vessels, as well as increased renal proximal tubular sodium reabsorption. An influence of heredity on this relationship is supported by four lines of evidence: 1) salt-sensitivity of blood pressure occurs predominantly in subjects with a family history of hypertension; 2) studies in twin children document the influence of genetic variance on salt-sensitivity of blood pressure; 3) subjects with a family history of hypertension have a significantly lower salivary sodium concentration and an altered urinary sodium excretion after salt loading compared to subjects with no such history; 4) salt-sensitivity of blood pressure may be associated with specific genetic markers. On the basis of these observations, we propose the hypothesis that enhanced inverse alpha-beta-adrenoceptor regulation in response to a high salt intake may be responsible for salt sensitivity in the normal population, and may contribute to the development of essential hypertension in susceptible individuals. This alteration is likely to be genetically mediated.

Physiological mechanism of digital vasoconstriction training

Recent work in our laboratory has shown that vasodilation produced during temperature biofeedback training is mediated through a nonneural, beta-adrenergic mechanism. Here we sought to determine if the effects of feedback training for vasoconstriction are produced through a neural or nonneural pathway and whether other measures of physiological activity are correlated with these changes. Nine normal subjects received temperature feedback vasoconstriction training in which feedback was delivered only during periods of successful performance. In a subsequent session, the nerves to one finger were blocked with a local anesthetic while finger blood flow was recorded from this and other fingers. Vasoconstriction occurred during feedback in the intact fingers but not in the nerve-blocked finger and was accompanied by increased skin conductance and heart rate. These data demonstrate that temperature feedback vasoconstriction training is mediated through an efferent, sympathetic nervous pathway. In contrast, temperature feedback vasodilation training is mediated through a nonneural, beta-adrenergic mechanism.

Training to vasodilate in a cooling environment: a valid treatment for Raynaud's phenomenon?

While many reports indicate that voluntary modification of skin temperature is possible and may be useful in the treatment of Raynaud's phenomenon, little attention has been paid to the ecological validity of training skin temperature increases when a considerable amount of vasodilation of digital vessels may already exist (room temperature, 22-24 degrees C). Patients with Raynaud's vasospastic attacks may benefit from learning to avoid attacks when they are impending by voluntarily vasodilating the vessels of their digits under conditions when vasoconstriction has begun. The results in 14 patients with primary and secondary Raynaud's phenomenon indicated that (a) patients learned to voluntarily increase digital skin temperatures in a "cooling" environment during documented vasoconstriction, and (b) there was a 31% decrease in the occurrence of vasospastic attacks following such learning. These data suggest that a new methodology may be useful in the biofeedback treatment of Raynaud's phenomenon, but further research is needed to determine the specific mechanism(s) involved, and the limits to its usefulness.

Sweat-gland necrosis after beta-adrenergic antagonist treatment in a patient with pheochromocytoma

We describe the dermatological consequences of treatment with a beta-adrenergic antagonist, atenolol, in a patient with pheochromocytoma. There were acral skin lesions, histologically characterized by epidermal and sweat-gland necrosis. It is believed that the combined action of severe local ischaemia and profuse sweating produced these lesions, which resembled histologically the changes found in patients comatose as the result of carbon monoxide or drug poisoning. The importance of such lesions in diagnosis is discussed.

Adrenergic and dopaminergic control of the canine paw microcirculation

Basal isolated canine paw blood flow was equally distributed between arteriovenous anastomosis (AVA) and capillary circulations. Norepinephrine decreased AVA flow by 92% and capillary flow by 41%. Dopamine significantly reduced AVA flow by 94% compared to baseline with a 37% reduction in capillary flow. However, with alpha-adrenergic blockade dopamine decreased AVA flow 66% while capillary flow increased 42%. Isoproterenol increased capillary flow almost twofold and appeared to decrease AVA flow, although the latter was statistically insignificant. Differential effects of adrenergic and dopaminergic agonists on canine paw AVA and capillary blood flow suggest the existence of independent regulation of these components of the microcirculation.

Failure of dobutamine to increase exercise capacity despite hemodynamic improvement in severe chronic heart failure

The acute hemodynamic and metabolic effects of dobutamine administered during exercise were studied in 8 patients with severe chronic heart failure. Exercise was performed on an upright bicycle ergometer using a graded protocol. During exercise performed without administration of dobutamine, exhaustion occurred after 4.5 +/- 1.2 minutes of exercise. The cardiac index increased from 1.61 +/- 0.25 to 2.67 +/- 0.59 liters/min/m2 (p less than 0.001), the arteriovenous oxygen difference from 7.8 +/- 1.7 to 12.5 +/- 2.4 ml/100 ml (p less than 0.001), and oxygen uptake from 7.9 +/- 3.0 to 41.2 +/- 15.7 mg/100 ml (p less than 0.001). During exercise performed with the administration of dobutamine, the cardiac index was significantly greater than during the control state, 3.23 +/- 0.78 versus 2.67 +/- 0.59 liters/min/m2 (p less than 0.001), while the arteriovenous oxygen difference was significantly lower, 11.2 +/- 2.1 vs 12.5 +/- 2.4 ml/100 ml (p less than 0.01). The arterial lactate level was not significantly changed, 45.3 +/- 17.6 versus 41.2 +/- 15.7 mg/100 ml. Although the dobutamine level tended to increase maximal oxygen uptake compared with the control period of exercise, 9.1 +/- 1.2 versus 8.5 +/- 1.4 ml/kg/min (p less than 0.05), it did not significantly increase exercise capacity, 4.8 +/- 1.5 versus 4.5 +/- 1.2 min. Thus administration of dobutamine in patients with severe chronic heart failure increased the cardiac index during maximal exercise but failed to increase exercise capacity. Since arteriovenous oxygen difference is reduced, dobutamine probably increases blood flow to the nonexercising tissues and not to the actively metabolizing muscles.