Sympathetic Interaction Research Articles

Circadian change of cardiac autonomic function in correlation with intra‐esophageal pH

Although autonomic alterations are observed in patients with gastroesophageal reflux disease (GERD), the influence of visceral receptor responses on the dynamics of autonomic function remains unknown. The aim of this study was to investigate the autonomic functional changes in association with intra-esophageal pH under ambulation. Thirty patients referred for 48 h ambulatory pH monitoring underwent simultaneous 24 h cardiac monitoring for heart rate variability (HRV). We used linear mixed-effects models to estimate the relationship between esophageal acid exposure and power spectral analysis of HRV, including low-frequency power (0.04 < LF < 0.15 Hz), high-frequency power (0.15 < or = HF < 0.4 Hz), and LF/HF power ratio. Over the 24-h period, patients with pathological reflux had lower average LF and HF powers than patients with functional heartburn, but the LF/HF power ratios were similar for the two patient groups. As we stratified the data according to waking and sleeping times, a significantly higher HF power but lower LF/HF power ratio was found during sleeping time regardless of diagnosis. In the regression analysis, esophageal pH was positively associated with change (not basal tone) of both LF and HF powers during waking, but only with change of HF power during sleeping time. The significant associations between pH values and changes in HRV decreased gradually with time. The LF/HF power ratio did not alter significantly with pH. Esophageal acid exposure is generally associated with decreases in autonomic tone. A predominant parasympathetic fluctuation during sleeping and a superimposed sympathetic interaction during waking dictate diurnal characteristics of autonomic regulation.

Dynamics of the 2‐day wave in a nonlinear model of the middle and upper atmosphere

The 2‐day wave is investigated in a three‐dimensional model of the nonlinear primitive equations. Extending upward from the tropopause into the thermosphere, the model is forced stochastically by fluctuations of tropospheric wave structure. The behavior recovered is broadly consistent with linear calculations of the Rossby‐gravity normal mode in the presence of instability. The mode's amplification depends sensitively upon details of the zonal‐mean flow, which determine instability through a reversal of potential vorticity (PV) gradient. On the other hand, the mode's period and structure are robust. They retain much the same form under a variety of conditions. The response is sharply discriminated to wave number 3 and westward periods of 2.0–2.3 days, even though forcing is broadband. Under January conditions, strong easterlies and the accompanying reversal of PV gradient enable the mode to amplify through sympathetic interaction with the mean flow. The amplifying signal eventually emerges from random variability, which is excited by broadband forcing. Amplification continues until eddy velocities approach 70 m/s, whereupon the signal saturates. Horizontal mixing then ensues, destroying the meridional gradient of PV, which in turn limits instability and further amplification. Under June conditions the response fluctuates randomly during the entire integration, with no evidence of sustained amplification. Nevertheless, it too is sharply discriminated to westward periods of 2.0–2.3 days, achieving eddy velocities of 10–20 m/s. The sharply discriminated response appears even when a reversal of PV gradient is absent, leaving the mean flow stable. Under all of these conditions the structure of eddy stream function Ψ′ is nearly barotropic, with antisymmetric character between the hemispheres. Eddy motion assumes the form of a wave‐number‐3 pattern of equatorial gyres, reducing in the tropics to v′ and strong cross‐equatorial motion. The pattern is very similar to the limiting structure of the 2‐day wave observed by UARS. Although magnified in the summer stratosphere and mesosphere, the structure of Ψ′ is global, with a phase reversal between the hemispheres. The modal structure extends upward into the thermosphere and, albeit weaker, as low as the tropopause.

Funding innovation and growth in UK new technology-based firms: Some observations on contributions from the public and private sectors

This paper explores the recent evolution of funding for New Technology-Based Firms (NTBFs) in the UK, with particular concern for the post-1980 period. Special attention is placed upon the relationship between public and private sector funding, and the ways in which these different funding cultures impact upon NTBF development. By citing a number of practical examples, the paper argues that a better integration of public and private sector funding would be to the advantage of all funders, the recipients and the wider economies in which all those involved co-exist. Improved collaboration would create a funding whole, achieved through sympathetic interaction between the public and private sectors, of greater value than the sum of its constituent parts.

'Verstehen' heißt nicht 'mögen'

The discussion in the entire area of "intercultural communication" revolves around the issue of facilitating mutual understanding between members of ethnic and cultural communities. The basic assumption is that once this has been achieved, the fundamental problems have been addressed, thereby removing the obstacles for sympathetic interaction. The conclusion that understanding is a necessary condition for liking, is, however, faulty. Empathy and sympathy are - even though related - not identical. In this contribution I will argue that getting to know the "other" better will not automatically result in liking him/her more. The history of exotism from Marco Polo via Columbus to even such sober characters as James Cooke shows that phenomena which are not understood may create very strong positive feelings whereas in an intracultural setting which is certainly not ridden by difficulties encountered in intercultural exchange, we do find clearly marked antipathies. A further topic to be addressed is the issue of whether the matters in question are intrinsically accessible and capable of being mediated in formal instruction.

Thyroid hormone–sympathetic interaction and adaptive thermogenesis are thyroid hormone receptor isoform–specific

In newborns and small mammals, cold-induced adaptive (or nonshivering) thermogenesis is produced primarily in brown adipose tissue (BAT). Heat production is stimulated by the sympathetic nervous system, but it has an absolute requirement for thyroid hormone. We used the thyroid hormone receptor-β–selective (TR-β–selective) ligand, GC-1, to determine by a pharmacological approach whether adaptive thermogenesis was TR isoform–specific. Hypothyroid mice were treated for 10 days with varying doses of T3 or GC-1. The level of uncoupling protein 1 (UCP1), the key thermogenic protein in BAT, was restored by either T3 or GC-1 treatment. However, whereas interscapular BAT in T3-treated mice showed a 3.0°C elevation upon infusion of norepinephrine, indicating normal thermogenesis, the temperature did not increase (<0.5°C) in GC-1–treated mice. When exposed to cold (4°C), GC-1–treated mice also failed to maintain core body temperature and had reduced stimulation of BAT UCP1 mRNA, indicating impaired adrenergic responsiveness. Brown adipocytes isolated from hypothyroid mice replaced with T3, but not from those replaced with GC-1, had normal cAMP production in response to adrenergic stimulation in vitro. We conclude that two distinct thyroid-dependent pathways, stimulation of UCP1 and augmentation of adrenergic responsiveness, are mediated by different TR isoforms in the same tissue.

"Launched into Eternity:" Sympathetic Interaction as a Response to Public Executions in Canada West, 1847-1869

In this article, ideas central to Adam Smith’s Theory of Moral Sentiments as well as those of Benthamite reformers are shown to have informed legislative reports and statutes enacted during a period of legal and penal reform in Upper Canada/Canada West. Using newspaper reports, this article discusses the relationship of these themes to narratives of public executions. In the context of an increasingly democratic state in Canada West, sympathetic interaction between the condemned and the community appeared as the foundation of moral lessons to be drawn from the experience of public hangings.

Harmonic analysis of transient currents during sympathetic interaction

The phenomenon of sympathetic interaction between transformers, which is very likely to occur when a transformer is energised onto a system to which there are other transformers already connected, changes significantly the duration and the magnitude of the transient magnetising currents in the transformers involved. This phenomenon is discussed in the paper, with the harmonic content of the transient currents and its associated overvoltages being analysed. It is shown that the importance of taking into consideration the saturation characteristics of the transformers already in operation when studying transformer transient inrush.

Phenomenon of sympathetic interaction between transformers caused by inrush transients

In power systems with appreciable resistance, the transformers already connected to the supply system can experience unexpected saturation during the inrush transient of an incoming transformer. This saturation, which is established by the asymmetrical voltage drop across the system resistance caused by the inrush current, demands offset magnetising currents of high magnitude in the already connected transformers. This generates a transient interaction between the transformers, a &apos;sympathetic interaction&apos;, that affects the magnitude and duration of the inrush current. As a consequence, problems in the operation of the system, such as false operation of transformer differential relays and prolonged temporary harmonic overvoltages, can occur. The sympathetic interaction between the transformers is analysed in the paper. System configurations with transformers in parallel and in series are investigated. The transformers and system models have been validated using small transformers.

Sympathetic and parasympathetic interaction in vascular control of the nasal mucosa in anaesthetized cats.

1. In cats anaesthetized with pentobarbitone sodium (45 mg kg-1), electrical stimulation of the parasympathetic nerve fibres to the nasal mucosa evoked frequency-dependent increases in nasal arterial blood flow whereas stimulation of the superior cervical sympathetic nerve induced marked vasoconstriction. 2. Sympathetic nerve stimulation for 3 min at 10 Hz evoked significant (P < 0.05) and prolonged (> 30 min) attenuation of the vasodilatory response to subsequent parasympathetic stimulation. 3. Combined pretreatment with adrenergic and cholinergic blockers reduced the vasoconstrictory effect of sympathetic stimulation by 28 +/- 4% (mean +/- S.E.M.) and the parasympathetically evoked vasodilatation by 20 +/- 5%. 4. The vasodilatory effects of exogenous vasoactive intestinal polypeptide, peptide histidine isoleucine and galanin, and the vasoconstrictory effects of exogenous neuropeptide Y (NPY) and alpha,beta-methylene adenosine 5'-triphosphate were not altered by adrenoceptor antagonists and atropine whereas the effects of exogenous noradrenaline and acetylcholine were virtually abolished. 5. The atropine-resistant parasympathetic vasodilatation remained significantly attenuated for more than 30 min after the non-adrenergic sympathetically evoked vasoconstriction. 6. Exogenous NPY (25 x 10(-9) mol) mimicked the effect of sympathetic stimulation in attenuating subsequent parasympathetically evoked vasodilatation.

Planetary-Scale Circulations in the Presence of Climatological and Wave-Induced Heating

Interaction between the large-scale circulation and the convective pattern is investigated in a coupled system governed by the linearized primitive equations. Convection is represented in terms of two components of heating: A 'climatological component' is prescribed stochastically to represent convection that is maintained by fixed distributions of land and sea and sea surface temperature (SST). An 'induced component' is defined in terms of the column-integrated moisture flux convergence to represent convection that is produced through feedback with the circulation. Each component describes the envelope organizing mesoscale convective activity. As SST on the equator is increased, induced heating amplifies in the gravest zonal wavenumbers at eastward frequencies, where positive feedback offsets dissipation. Under barotropic stratification, a critical SST of 29.5 C results in positive feedback exactly cancelling dissipation in wavenumber 1 for an eastward phase speed of 6 m/s. Sympathetic interaction between the circulation and the induced heating is the basis for 'frictional wave-Conditional Instability of the Second Kind (CISK)', which is distinguished from classical wave-CISK by rendering the gravest zonal dimensions most unstable. Under baroclinic stratification, the coupled system exhibits similar behavior. The critical SST is only 26.5 C for conditions representative of equinox, but in excess of 30 C for conditions representative of solstice. Having the form of an unsteady Walker circulation, the disturbance produced by frictional wave-CISK compares favorably with the observed life cycle of the Madden-Julian oscillation (MJO). SST above the critical value produces an amplifying disturbance in which enhanced convection coincides with upper-tropospheric westerlies and is positively correlated with temperature and surface convergence. Conversely, SST below the critical value produces a decaying disturbance in which enhanced convection coincides with upper-tropospheric easterlies and is nearly in quadrature with temperature and surface convergence. While sharing essential features with the MJO in the Eastern Hemisphere, frictional wave-CISK does not explain observed behavior in the Western Hemisphere, where the convective signal is largely absent. Comprised of Kelvin structure with the same frequency, observed behavior in the Western Hemisphere can be understood as a propagating response that is excited in and radiates away from the fluctuation of convection in the Eastern Hemisphere.

Sympathetic and parasympathetic interaction in vascular control of the cat nasal mucosa

Sympathetic and parasympathetic interaction in vascular control of the cat nasal mucosa

Randomized double‐blind trial of injectable heptaminol for controlling spontaneous or bromocriptine‐induced orthostatic hypotension in parkinsonians

Heptaminol is a molecule with experimental cardiovascular analeptic properties. In this double-blind vs placebo trial, the potency, so far unproven, of the injectable form of a 626 mg dose of heptaminol chlorhydrate on spontaneous or induced orthostatic hypotension (OH), was assessed. Nineteen patients were included in the study: 7 displayed spontaneous OH, and in the other 12 OH was induced by bromocriptine, as monitored 103 min/after an oral intake of 6.6 mg on average. Neither spontaneous nor induced OH were recorded in 32% of the Parkinsonian population registered, with no obvious distinctive characteristics. Potency tilt-trials, performed 15, 30 and 45 min after parenteral administration of heptaminol, revealed a significant and expressive potency of the molecule on the systolic blood pressure after 15 min (P less than 0.05). Clinical and biological tolerance was excellent. Low plasma renin activity and the absence of response to orthostatism indicated, in this population of Parkinsonian extrapyramidal syndromes, a loss in positive tonus likely to be of sympathetic origin. The anti-hypotensive action of heptaminol does not seem to be related to any renal or even sympathetic interaction.

Psychophysical observations on patients with neuropathic pain relieved by a sympathetic block

Patients with sympathetically maintained pain (SMP) were tested with noxious heat pulses, innocuous mechanical stimuli, and transcutaneous electrical nerve stimulation before and during local anesthetic sympathetic blocks that relieved their pain. The perceived intensity of the pain evoked by these stimuli was measured by the patients' responses on a visual analog scale and compared to the responses obtained when the same stimuli were applied to contralateral normal skin. In 5 of 7 patients tested, graded noxious heat stimuli (43–51°C) applied to painful skin resulted in heat-pain intensity ratings that were essentially identical to the responses obtained when the same stimuli were applied to the normal side. Of the remaining two patients, one was clearly hypoalgesic for heat-pain and the other was probably hyperalgesic. The normal and subnormal heat-evoked responses obtained from abnormal skin were unchanged during completely successful sympathetic blocks. Trains of noxious heat pulses (52° C) evoked summation of the second pain sensation in each of the 4 patients tested. This summation effect was normal and unaffected by a sympathetic block. Four of the patients had allodynia evoked by mechanical stimulation. In each of the 3 allodynia cases tested, transcutaneous nerve stimulation at an intensity that was at threshold for detection evoked burning pain and a coexistent sensation of tingle, indicating that both sensations were due to the activation of Aβ axons. Patients without touch-evoked pain reported that electrical stimuli at threshold for detection produced only the sensation of tingle. The pains evoked by touch and by threshold-strength nerve stimulation were eliminated during sympathetic block. In patients with allodynia, trains of gentle mechanical stimuli and trains of threshold-strength electrical nerve stimuli produced summation of the intensity of the burning pain sensation when the stimuli were presented at 0.3 Hz. These results add to a growing body of evidence indicating that the touch-evoked pain of some patients is due to abnormal central activity evoked by input from Aβ low-threshold mechanoreceptors. The coexistence of Aβ-evoked pain with normal heat-evoked pain and normal heat-pain summation suggests that the central abnormality cannot be a simple hypersensitivity of wide-dynamic-range neurons. The effect of sympathetic blockade on Aβ-evoked pain and its summation suggests that the crucial sympathetic interaction may take place centrally. The results show that there is considerable heterogeneity of sensory abnormalities among patients with SMP. Lastly, the results indicate that the different kinds of disordered pain sensation seen in painful peripheral neuropathies may each have different underlying neuropathic mechanisms.

Targets and interrelation of nerves coding for substance P, multiple non-tachykinin peptides and/or catecholamines in guinea-pig adrenal gland: Multiple messengers in sensory and sympathetic neuroendocrine interaction?

Targets and interrelation of nerves coding for substance P, multiple non-tachykinin peptides and/or catecholamines in guinea-pig adrenal gland: Multiple messengers in sensory and sympathetic neuroendocrine interaction?

Autopsy—Current Issues-Reply

In Reply.— Interpersonal relationships between physician and family are important when requesting autopsy. The request for autopsy occurs during a time of intense emotional experience for bereaved families and requires a balance between the science and the art of medical practice, and between the expansion of knowledge and respect for human suffering. In every case, scientific inquiry should be secondary to concern for individuals. 1 Several authors have addressed the complexity of acquiring permission for autopsy after death. 2-4 Effective counseling and support for the bereaved require education of physicians to achieve effective and sympathetic interaction. Role modeling by faculty as a method of teaching is highly recommended to demonstrate prevailing attitudes, religious dicta, and scientific imperatives. 5 Discomfort surrounding requests for autopsy could be reduced by educating the public on the benefits of this procedure. Appreciation for the role of autopsy in helping to assuage grief by explaining the

Vasoactivity of Verapamil in the Canine Hindlimb and Sympathetic Nervous System Interaction

Since enhanced sensitivity to verapamil in essential hypertension has been noted, a relationship between verapamil and the sympathetic nervous system has been suggested. It has also been noted that both verapamil and lumbar sympathectomy appear to decrease the vasospasm seen in Raynaud's phenomenon. To further investigate the possible interrelationship between verapamil and the sympathetic nervous system, a unilateral lumbar sympathectomy was performed on eight dogs. Two weeks later the femoral artery blood flow response to intra-arterial verapamil was compared on the sympathectomy limb side and the non-sympathectomy limb side. Blood flow measurements were done without surgical trauma by video dilution technique. Although baseline femoral artery blood flow was unchanged and equal on both sides following sympathectomy (4.6% of cardiac output), there was a significant rise, p less than 0.05, in the blood flow response to verapamil on the side of sympathectomy. Therefore, sympathectomy appears to enhance the calcium channel blocking properties of verapamil.

Vasoactivity of Verapamil in the Canine Hindlimb and Sympathetic Nervous System Interaction

Vasoactivity of Verapamil in the Canine Hindlimb and Sympathetic Nervous System Interaction

Developmental changes in the interactions of cholinergic and beta-adrenergic agonists on electrophysiologic properties of canine cardiac Purkinje fibers.

The parasympathetic nervous system attenuates the effects of sympathetic interventions on the hearts of mature animals. Whereas the vagal mediator, acetylcholine (ACh), alone has minor effects on electrophysiologic properties of the ventricular conducting system, in the presence of sympathetic amines, it induces an accentuated antagonism. Because there are developmental changes in both sympathetic and parasympathetic effects on the heart we studied the parasympathetic and sympathetic interaction in isolated neonatal canine Purkinje fibers (PF), and compared the results to those in adult PF. PF were exposed to isoproterenol (Iso) alone (1 X 10(-9), 1 X 10(-7) and 1 X 10(-5) M) to ACh alone (1 X 10(-7) or 1 X 10(-5) M) and to Iso in the presence of ACh. In adult PF, superfusion with Iso, 10(-5) M, alone shortened action potential duration to 50% repolarization from a control value of 215 +/- 9 to 200 +/- 9 ms (p less than 0.01). Simultaneous superfusion of adult PF with Iso 10(-5) and Ach 10(-5) M decreased the extent of action potential shortening produced by Iso, so that action potential duration to 50% repolarization shortened from a control value of 221 +/- 8 to only 214 +/- 12 ms (p less than 0.01). The response to superfusion with Iso and Ach (10(-5) M) differed significantly from that with Iso alone (p less than 0.01). In contrast, exposure of neonatal PF to Iso (10(-5) M) prolonged action potential duration to 50% repolarization from a control value of 157 +/- 7 to 180 +/- 5 ms (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Elevated sympathetic response of epicardium proximal to healed myocardial infarction.

Sympathetic nerve interaction with cardiac electrophysiology was evaluated in healed myocardial infarction by monitoring the effects of sympathetic nerve stimulation on local epicardial refractoriness in cats. Single-stage distal coronary artery ligation was used to induce myocardial infarction. Regions overlying and surrounding infarcts 3 mo after healing and comparable regions in sham-operated and normal unoperated hearts were studied. Local ventricular muscle refractory periods were measured by the extrastimulus technique from 1) the epicardium overlying the infarct, 2) the area bordering the infarct, and 3) a normal area proximal to the infarct on the anterior free wall of the left ventricle. Bilateral stimulation of the ansa subclavia induced significant and disparate refractory period shortening (P less than or equal to 0.01) in hearts with healed myocardial infarction. Shortening was greatest in the normal area [-26 +/- 8 (+/-SD) ms], less in the border area (-15 +/- 6), and least in the infarct area (-7 +/- 2). In contrast, refractory periods measured in noninfarcted hearts shortened significantly (P less than or equal to 0.01) but uniformly and to a lesser extent during sympathetic stimulation. We conclude 1) the effects of sympathetic nerve stimulation are more pronounced in the areas proximal to healed infarction than in similar areas of noninfarcted hearts and 2) a marked disparity in sympathetic responsiveness occurs in hearts with healed myocardial infarction.

Gastroenterological sit-in.

AN unusual sit-in is scheduled this fall for Saturday, October 23. Its objective is promotion rather than protest, and its sponsors are at the core of establishment. Specifically, similar all-day sessions will be held in Pittsburgh, Pennsylvania, San Antonio, Texas, and Portland, Oregon, to promote intellectual and sympathetic interaction between the specialist in gastroenterology and the physician who gives primary care. The sponsors are, on the one hand, the American Gastroenterological Association (AGA), and, on the other, the State Academies of General Practice and the local medical schools. At each session, a panel of specialists and an audience of practitioners . . .