Rebound cardiovascular responses following stimulation of canine vagosympathetic complexes or cardiopulmonary nerves

Electrical stimulation of a canine vagosympathetic complex or a cardiopulmonary nerve can elicit a variety of negative chronotropic and inotropic cardiac responses, with or without alterations in systemic arterial pressure. In the period immediately following cessation of such a stimulation "rebound" tachycardia, increased inotropism above control values in one or more regions of the heart, and (or) elevation in systemic arterial pressure can occur. These "rebound" phenomena are abolished by propranolol or ipsilateral chronic sympathectomy. It is proposed that "vagal" poststimulation "rebound" of the canine cardiovascular system is primarily the result of activation of sympathetic neural elements present in the vagosympathetic complexes or cardiopulmonary nerves.     

Heart muscle: mathematical modelling of the mechanical activity and modelling of mechanochemical uncoupling

A mechanical model of heart muscle is proposed which includes rheological equations and equations for Ca-troponin interaction, for the dependences of the number of myosin cross-bridges on the length of sarcomere and on the speed of motion. The main assumption of the model is the dependence of the troponin affinity to calcium ions on the number of myosin cross-bridges attached. The model successfully imitates isometric and isotonic contractions, the "length-force" relationships, load-dependent relaxation, and the group of mechanical phenomena known as mechanochemical uncoupling.     

Reaction of substrates with 35S-thiophosphorylated succinyl-CoA synthetase of pig heart. Similarities to the case of the Escherichia coli enzyme

Guanosine 5'-O-(3-thio)triphosphate (GTP gamma S) was found to be a substrate of pig heart succinyl-CoA synthetase with Km and kcat values of 3 microM and 0.23 s-1, respectively. The corresponding values with GTP as substrate were 48 microM and 65 s-1. 35S-thiophosphorylated enzyme was prepared by incubation of pig heart succinyl-CoA synthetase with [35S]GTP gamma S. A comparison was made of thiophosphoryl group release by substrates from this alpha beta (one active site) enzyme with that of the alpha 2 beta 2 (two active sites) Escherichia coli enzyme (Wolodko, W. T., Brownie, E. R., O'Connor, M. D., and Bridger, W. A. (1983) J. Biol. Chem. 258, 14116-14119; Nishimura, J. S., and Mitchell, T. (1984) J. Biol. Chem. 259, 9642-9645). It was found, as in the case of the E. coli enzyme, that thiophosphoryl group release by GDP and by succinate plus CoA was stimulated by succinyl-CoA and GTP, respectively. The same result was observed at 1, 0.1, and 0.01 mg/ml, lending assurance that these phenomena were not exhibited by an aggregated form of the pig heart enzyme. While an alternating-sites catalytic cooperativity model is not ruled out for the E. coli enzyme, it is proposed that the NTP- and succinyl-CoA-stimulated release of thiophosphoryl groups from either enzyme involves a "same-site" mechanism, to be distinguished from an "other-site" mechanism.     

Reduced Penetrance and Variable Expression of SCN5A Mutations and the Importance of Co-inherited Genetic Variants: Case Report and Review of the Literature

Mutations in the SCN5A gene are responsible for multiple phenotypical presentations including Brugada syndrome, long QT syndrome, progressive familial heart block, sick sinus syndrome, dilated cardiomyopathy, lone atrial fibrillation and multiple overlap syndromes. These different phenotypic expressions of a mutation in a single gene can be explained by variable expression and reduced penetrance. One of the possible explanations of these phenomena is the co-inheritance of genetic variants. We describe a family where the individuals exhibit a compound heterozygosity in the SCN5A gene including a mutation (R1632H) and a new variant (M858L). Individuals with both the mutation and new variant present with a more severe phenotype including spontaneous atrial tachyarrhythmia at young age. We give an overview of the different phenotypes of "SCN5A disease" and discuss the importance of co-inherited genetic variants in the expression of SCN5A disease.     

Temporally Resolved Fluctuation Analysis of Sleep ECG

The correlation behavior in the heart beat rate significantly differs with respect to light sleep, deep sleep, and REM sleep. We investigate whether fluctuations of the heart beat rhythm may serve as a surrogate parameter for rapidly changing sleep phenomena, and if these changes are accessible by progressive beat-by-beat analysis of the sleep electrocardiogram (ECG).     

大足鼠耳蝠交流声波非线性现象

非线性发声现象在动物的发声中普遍存在,因其具有进化上的意义而广受关注。非线性现象一般在动物激进状态下发出,可能具有一定的功能,然而国内外对蝙蝠非线性现象的研究集中于描述性的报道,缺乏进化功能上的探究。大足鼠耳蝠(Myotis pilosus)激进叫声包含2种音节类型,拱形调频音节(AFM)和噪音-短下调调频音节(NB-s DFM),能够组成3种叫声组合,只包含AFM的叫声组合(A)、只包含NB-s DFM的叫声组合(B)、既包含AFM又包含NB-s DFM的叫声组合(C),分别对应着没有非线性现象、具有非线性现象及一种过渡类型。通过回放3种叫声组合,记录7种具有代表性的行为反应(抬头、前臂移动、耳动、发出回声定位脉冲、震颤、张嘴、爬行)次数,其中,前臂移动和发出回声定位脉冲两种行为反应的结果显示,大足鼠耳蝠对上述3种叫声组合的反应程度有显著差异,即具有非线性现象的叫声组合(B)能够提高同种蝙蝠的反应程度。实验结果表明,蝙蝠发声中的非线性现象能够增强叫声的不可预测性,说明非线性现象在蝙蝠发声中可能具有功能上的适应性。     

Simulation by two calcium store models of myocardial dynamic properties: potentiation, staircase, and biphasic tension development

Most considerations and models concerning myocardial dynamic properties e.g. potentiation and staircase, are based upon the existence of storage structures in the heart muscle cell. The phenomenon of biphasic tension development (or two-component contraction) in heart muscle preparations of several mammalian species suggests that the sarcoplasmic reticulum is one, but by no means the major, source of activator calcium for the contractile system. The simulation of dynamic properties including biphasic tension development was performed in two steps by a simple "two-Ca store-model" and by an "expanded two-Ca store-model" with following results: Increasing potentiation indicated a decrease in the degree of coupling between the Ca stores. A shift of the interval strength curve to lower intervals as well as a decrease of the steady state contraction height implies a decrease of both, the coupling and the leakage time constant. There was no standard relation between staircase phenomena and structure parameters. Analog displays showed a late (or second) component at prolongated stimulation intervals, in the transient phase after a rest period, in the case of perfectly coupled or uncoupled stores, and at great time constant tau p (which characterizes the calcium pump activity). It is concluded that the late component of biphasic tension development is due to direct activation by the transsarcolemmal Ca flux of the myofilaments, whereas the early component is caused by the release of stored calcium. In the absence of an early component neither potentiation nor marked treppe may be expected.     

Spectroscopy of plasma by proton magnetic resonance during cardiac transplantation

Proton magnetic resonance spectroscopy of plasma indicates an alteration of proteolipid methyl and methylene resonances after heart transplantation. The intensity of these alterations is modulated by the transplant tolerance phenomena and allows the accurate detection of heart graft rejection. These results reinforce the analogy between the immunology of graft tolerance and the immunology of cancer or pregnancy where identical alterations have been identified.     

Checkpoints and restriction points in bacteria and eukaryotic cells

Bacterial checkpoints, analogous to those proposed to exist in eukaryotic cells, offer insights into the definition of a checkpoint. Examination of bacterial "checkpoint" or arrest phenomena illustrate problems with a too-casual application of the checkpoint idea to eukaryotic phenomena. The question raised here is whether there are cellular processes that "check" whether a cellular process is completed. It is possible that many eukaryotic "checkpoints" may not have "checking" functions. Some of the ubiquitous checkpoint phenomena widely described may be merely the result of the inherent incompleteness of earlier events preventing the initiation of subsequent events.     

The duality of the qualitative determinacy of the epidemic process in anthroponoses as the main trait distinguishing them from the epidemic manifestations of zoonotic diseases in man

The present article substantiates the necessity of defining more accurately the notion "epidemic process" and using this term only in reference to anthroponotic diseases. Proceeding from the philosophical concept of the qualitative definiteness of material objects and phenomena, the author proposes to distinguish the epidemic process in anthroponoses from mass spread of zoonotic diseases among humans on the basis of using the systemic qualities of the epidemic process, and in particular the principle of the dual character of the qualitative definiteness of objects and phenomena as the distinctive feature of the epidemic process of anthroponoses. Distinction, based on this principle, between anthroponotic diseases and zoonotic diseases in groups of humans must be reflected in the definitions of these phenomena. The application of the term "epidemic process" only in reference to anthroponotic diseases is proposed, while zoonotic diseases in groups of humans should be considered as epidemic manifestations of zoonotic infections.     

LTP and LTD: an embarrassment of riches

LTP and LTD, the long-term potentiation and depression of excitatory synaptic transmission, are widespread phenomena expressed at possibly every excitatory synapse in the mammalian brain. It is now clear that "LTP" and "LTD" are not unitary phenomena. Their mechanisms vary depending on the synapses and circuits in which they operate. Here we review those forms of LTP and LTD for which mechanisms have been most firmly established. Examples are provided that show how these mechanisms can contribute to experience-dependent modifications of brain function.     

The fundamental law of electrostimulation

Around the turn of the last century, there was intensive discussion among physiologists as to whether there was a law that described the phenomena of electrostimulation. In 1892 J.L. Hoorweg became the first to put electrostimulation on a quantitative footing. As early as 1901 G. Weiss formulated a law which made it possible to compare the effect of stimulation pulses of different shape. In 1909 L. Lapicque introduced the terms "rheobase" and "chronaxie", thus giving the "fundamental law of electrostimulation" its final form, which is still valid today. We are now able to give Lapicque's Law a physical interpretation. It is the electric field which is important for initiating electrostimulation by acting directly on the permeability of the membrane. The size of this field is produced by a transformation of the low extracellular field by the membrane. The consequences arising from the theory and our hypothesis are remarkable, and are illustrated for a number of practical problems. Thus, for example, a current of 50 Hz is dangerous if it creates an electric field strength within the heart of 34 V/m or more. For frequencies above 10 kHz the danger threshold increases by 20 dB/octave.     

Fluorescent histochemical studies on the effects of 6-hydroxydopamine on adrenaline-containing nerves in the toad

Summary Fluorescence histochemistry has been used to study the effects of 6-hydroxydopamine (6-OHDA) (100 mg/kg injected into the dorsal lymph sac) on adrenaline-containing nerves in the large intestine, mesentery, lung, bladder and heart atria of the toad Bufo marinus. A gradual decrease both in fluorescence intensity and in number of detectable fibres during the first 4 hours after 6-OHDA was accompanied by a build-up of fluorescence in the nonterminal regions. These phenomena have been discussed in relation to the time course of the degeneration produced by 6-OHDA in noradrenergic nerves of higher vertebrates. Almost complete chemical sympathectomy was seen after one day, and it was not till 13 days that regenerating nerve fibres were seen in any organ. In the large intestine, however, re-innervation was slower, being first noted after 39 days. The time course of regeneration has been compared with that following sympathectomy in various mammalian organs.     

The cardiosynchronous phenomena of the work of the brain: the psychophysiological aspects]

The review is devoted to the heartbeat-related components of EEG and to the heartbeat-related oscillation of performance measures and the cortical evoked potentials. The studies of these phenomena are carried out within the Laceys' hypothesis elaboration as well as in the field of the exploration of visceral self-perception. The data obtained in these studies indicate that there are elements of the time-locking with heart rate, probably unrelated to cardiovascular regulation, in functioning of the highest brain structures. The problems in the interpretation of some of heartbeat-related phenomena of brain functioning and their possible participation in the mechanisms of the psychophysiological interaction are discussed.     

A systems-analytical approach to macro-evolutionary phenomena.

Two sets of evolutionary phenomena find no explanation through current theory. For the static phenomena (such as homology, homonomy, systematic weight, and "Type") there is no causal base, although these principles are responsible for all phenomena of predictable order in the living world. The dynamic phenomena (such as homodynamy, coadaptation, parallel evolution, orthogenesis, Cartesian transformation, typostrophy, hetermorphosis, systemic mutation, and spontaneous atavism) have no causal explanation, although they are responsible for all directed phenomena in macroevolution. These phenomena share one unifying principle which can be explained by a system theory of evolution based on, but extending, the current synthetic theory. This system theory envisages feedback conditions between genotype and phenotype by which the chances of successful adaptation increase if the genetic units, by insertion of superimposed genes, copy the functional dependencies of those phene structures for which they code. This positive feedback of the adaptive speed (or probability) within a single adaptive direction is compensated by negative feedback in most of the alternative directions. The negative feedback operates as selection not be environmental but by systemic conditions developed by the organization of the organism. The consequences are an imitatively organized system of gene interractions, the rehabilitation of classical systematics, the reality of the "natural system," and, in general, the resolution of the contradiction between neodarwinists and their critics, between reductionists and holists, between "a priori" and "a posteriori" views, between idealism and materialism, and between the notions of freedom and of purpose in evolution.     

Usefulness of amplitude as a rheographic-cardiographic parameter for evaluation of degree of heart failure]

Impedance rheographic-cardiography has been performed in 40 patients with chronic congestive heart failure. At the same time, polycardiographic data have been recorded and used for the correlative analysis. A curve dZ/dt has been analysed and "S", "X", "A", "O" waves amplitudes together with A/S and X/S ratios have been calculated, depending on the degree of heart failure. It was found, that rheographic-cardiography may be valuable technique for the assessment of the degree of heart failure. Curve dZ/dt in patients with more advanced heart failure is of hypodynamic character (decrease in "S", "X", and "A" waves amplitude with an increase in "O" wave amplitude), being similar to sinusoidal curve. The most valuable rheographic-cardiograph parameters enabling the assessment of heart failure are: "S" and "O" waves amplitudes, and A/S and X/S ratios. Correlative analysis has also shown several important relationships between rheographic-cardiographic and polycardiographic parameters, which may facilitate the assessment of heart failure.     

Cardiac cell: a biological laser?

We present a new concept of cardiac cells based on an analogy with lasers, practical implementations of quantum resonators. In this concept, each cardiac cell comprises a network of independent nodes, characterised by a set of discrete energy levels and certain transition probabilities between them. Interaction between the nodes is given by threshold-limited energy transfer, leading to quantum-like behaviour of the whole network. We propose that in cardiomyocytes, during each excitation-contraction coupling cycle, stochastic calcium release and the unitary properties of ionic channels constitute an analogue to laser active medium prone to "population inversion" and "spontaneous emission" phenomena. This medium, when powered by an incoming threshold-reaching voltage discharge in the form of an action potential, responds to the calcium influx through L-type calcium channels by stimulated emission of Ca2+ ions in a coherent, synchronised and amplified release process known as calcium-induced calcium release. In parallel, phosphorylation-stimulated molecular amplification in protein cascades adds tuneable features to the cells. In this framework, the heart can be viewed as a coherent network of synchronously firing cardiomyocytes behaving as pulsed laser-like amplifiers, coupled to pulse-generating pacemaker master-oscillators. The concept brings a new viewpoint on cardiac diseases as possible alterations of "cell lasing" properties.     

Restrictive surgical approach to palliate angina in a patient with coronary three vessel disease and biventricular metastatic hepatocellular carcinoma

Background

Metastatic cardiac tumors may cause different symptoms including angina, symptoms of heart failure and/or arrhythmia. In patients with concomitant coronary artery disease, it may be difficult to distinguish between angina caused by metastases to the heart, for example, by stealing perfusion from the coronary arteries, and angina caused by coronary stenosis. Identifying the origin of the symptoms is, however, essential for designing appropriate surgical strategies.

Case presentation

A 69-year-old male with multifocal recurrence of a hepatocellular carcinoma (HCC) presented with increasing ventricular arrhythmia and angina several weeks after posterior myocardial infarction and PCI of the RCA culprit lesion during which two further lesions present in the distal RCX and a posterolateral branch, and a chronically occluded LAD had not been addressed. MRI showed a large metastatic tumor infiltrating the walls of both ventricles as well as the interventricular septum. His debilitating symptoms were attributed to steal phenomena and/or perivascular compression caused by the metastatic tumor rather than the remaining coronary lesions, and he was offered a restrictive surgical approach consisting of debulking of the metastasis with an option for subsequent coronary intervention. The palliative surgical procedure resulted in a reduction of the tumor mass by half and sufficiently reduced the patient’s symptoms so that further coronary intervention was not required.

Conclusions

Palliative surgery for metastases to the heart may benefit patients, provided that the origin of symptoms is identified correctly. It goes without saying that in a palliative setting, surgery should be limited to treating symptoms rather than performing extensive procedures addressing, for example, coronary artery or valve disease. Interventional cardiac procedures addressing not only CAD but also valve disease may supplement palliative tumor surgery.

     

Nonlinear acoustics in pant hoots of common chimpanzees (Pan troglodytes): frequency jumps, subharmonics, biphonation, and deterministic chaos

The pant hoot calls produced by common chimpanzees (Pan troglodytes) are multi-call vocalizations that have figured prominently in investigations of acoustic communication in this species. Although pant hoots are predominantly harmonically structured, they can exhibit an acoustic complexity that has recently been linked to nonlinearity in the vocal-fold dynamics underlying typical mammalian sound production. We examined the occurrence of these sorts of nonlinear phenomena in pant hoot vocalizations, contrasting quieter and lower-pitched "introduction" components with loud and high-pitched "climax" calls in the same bouts. Spectrographic evidence revealed four kinds of nonlinear phenomena, including discrete frequency jumps, subharmonics, biphonation, and deterministic chaos. While these events were virtually never observed during the introduction, they occurred in more than half of the climax calls. Biphonation was by far the most common phenomenon, followed by subharmonics, chaos, and frequency jumps. Individual callers varied in the degree to which their climax calls exhibited nonlinear phenomena, but were consistent in showing more biphonation than other forms. These outcomes show that nonlinear phenomena are routinely present in chimpanzee pant hoots, and help lay the foundation for investigating the function of such events.