Do geomagnetic disturbances of solar origin affect arterial blood pressure?

OBJECTIVE: Episodic reports suggest that geomagnetic disturbances of solar origin are associated with biological and clinical events, including increased arterial blood pressure (BP). We reassessed this aspect by relating solar activity levels to ambulatory BP measured in our out-patient population. PATIENTS AND METHODS: The ambulatory BP measurements of 447 consecutive untreated patients attending a hypertension out-patient clinic who did a monitoring for diagnostic purposes over 5 years were retrieved. The mean daytime, night-time and 24-h BP and heart rate values were related to the temporally corresponding geomagnetic index k-sum obtained by the nearest observatory. K-sum is a local measurement of the irregular disturbances of the geomagnetic field caused by solar particle radiation. RESULTS: Significant to highly significant positive correlations were observed for k-sum with systolic (daytime and 24 h) and diastolic BP (daytime, night-time and 24 h), but not with heart rate. No correlations were found with the k-sum of 1 or 2 days before the monitorings. Multiple correlations which also included other potential confounding factors (date, age) confirmed a significant effect of k-sum on BP. Comparison made in season-matched subgroups of quiet and disturbed days (using three different criteria of definition), always showed significantly higher values in the disturbed days for all BP parameters except systolic night-time pressure. The difference between the quietest and the most disturbed days was of about 6 to 8 mm Hg for 24-h systolic and diastolic BP. CONCLUSION: These results are unlikely to be due to unrelated secular trends, but seem to reflect a real relation between magnetic field disturbances and BP.     

Mutations in CLCN5 chloride channel in Japanese patients with low molecular weight proteinuria

It was hypothesized based on previous laboratory observations and theoretical concepts that astronauts working at the "Mir" station under zero gravity conditions exhibit enhanced sensitivity to geomagnetic disturbances. The result of studies made it possible to reveal the dynamics of changes in cardiovascular characteristics separately in the main phase and the phase of storm restoration. A similar dynamics of cardiac activity was observed in experimental rabbits during geomagnetic storms.     

Qualitative and quantitative assessment of exposure to geomagnetic field variations on the functional status of the human brain

The comparison of functional dynamics of human brain with reference to qualitative and quantitative characteristics of local geomagnetic field (GMF) variations was conducted. It was showed that just local GMF variations can be a principal reason of modulation the human brain's functional state. The steady and unsteady states of human brain can be determined: by geomagnetic disturbances before the observation period; by structure and doses of GMF variations; by different combinations of qualitative and quantitative characteristics of GMF variations. The optimal level of GMF activity, manifested in periodic oscillations in certain amplitude-frequency range is demanded for steady brain's functional state. The decrease of optimal GMF activity level and the appearance of aperiodic disturbances of GMF can be a reason of unsteady brain's state.     

Masseter muscle hyperactivity and myofascial pain dysfunction syndrome: a relationship under stress

Myofascial pain dysfunction syndrome (MPD) of the temporomandibular joint (TMJ) is a psychophysiological disorder that develops because of hyperactive muscles of mastication. Ten women meeting criteria for MPD and 12 symptom-free women participated in the study. The rationale for this study was to observe cardiovascular and masseter muscle changes during four contiguous experimental periods: baseline/adaptation, reaction time, recovery, and relaxation. MPD patients showed less masseter muscle activity and higher heart rates at baseline than controls. Controls had significantly higher masseter EMG activity during reaction time. Both groups showed significant elevation in masseter muscle activity and heart rate over the 14-min reaction period. MPD patients' recovery from stress was equivalent to controls' for both heart rate and masseter muscle activity. MPD patients exhibited significantly slower reaction times than controls. The results suggest that masseter muscle hyperactivity may not account for the development and maintenance of MPD.     

Hybrid pharmacologic and ablative therapy: a novel and effective approach for the management of atrial fibrillation

PURPOSE: This paper presents a critical review of the literature on neurosensory disturbances associated with implant surgery. MATERIALS AND METHODS: The reviewed literature includes mainly retrospective implant studies and patients' surveys, as well as a few prospective psychophysical studies on sensory disorders following maxillofacial surgeries. RESULTS: The available data suggest that injury to the peripheral branches of the trigeminal nerve and subsequent sensory disturbances are potential complications following implant surgery. Cross-sectional studies suggest that gross tactile sensation was regained in the vast majority of patients. However, data on the spatial and temporal patterns of recovery of this and other somatic sensation such as fine touch, nociception, and temperature sense after implant surgery is still lacking. The prevalence of sensory disturbances depends on several factors: the site of implant placement, the type of surgical procedures adopted, the design of the studies, the sensitivity of the testing methods, the choice of the outcome measures, and the terminology used to describe sensory disturbances. Extreme variation in the reported prevalence of neurosensory disturbances (0% to 100%) suggest that these problems have not been adequately evaluated. CONCLUSION: Although sensory disturbances are transient in the majority of implant patients, their profound impact on the quality of life of the subjects affected and the possibility that they may persist clearly indicate that they should be identified and evaluated through prospective studies, using validated testing protocols and outcome measures.     

Genomic organization and cloning of the human homologue of murine Sipa-1

During the last years several attempts have been made to describe changes in the mental efficiency of astronauts during space missions by means of performance monitoring studies. These studies are characterized by repeated multivariate assessment of different functions of the human information-processing system. In the present paper, a first review of performance monitoring studies during short-term and long-term spaceflight is given. Despite the comparatively small number of studies, a fairly consistent pattern of effects can be derived: Whereas no or only slight impairments of elementary and complex cognitive functions or spatial processing were found in space, clear disturbances could be identified in visuo-motor tracking and dual-task performance. Both of these latter effects appear to be closely related to adaptation to altered gravity conditions. General issues of this strategy of research are discussed which concern the disentanglement of microgravity-related effects and unspecific stress effects on mental performance under conditions of spaceflight. In addition, possible mechanisms which may be responsible for tracking disturbances under microgravity are discussed, and some directions for future human performance research in space are outlined.     

The role of the opioid system in body adaptation and protection of the heart in stress

Literary data and the results of our own studies on the role of opioid neuropeptides in the adaptation of organism and heart protection under the action of extreme factors were analysed. The data on the cardioprotective, antiarrhythmic, neurohumoral, antistressor effects of enkephalins are grown. Possible mechanisms and the role of various populations of opiate receptors in the realisation of opioid peptides' adaptation effects are studied. The key role of endogenous opiate system in the mechanism of cardioprotective effects of natural adaptogens and adaptation is established.     

Mucopolysaccharidosis. Radiological and clinical aspects

These are congenital diseases that may be seen occasionally, both in males as in females with the exception of Hunter's syndrome which is exclusive of the male sex. This possibility should be suspected before a patient with or without mental retardation and bony malformations. It must be kept in mind there is no medical treatment for their relief. However, recent studies have established a cause of effect relationship of metabolic disturbances of cycopolysaccharides and their accumulation in different tissues of the body, amongst them cartilages (chondrocytes), which would be responsible for the corresponding disturbances seen. Bony age was always found to be less than the chronological. Bony malformations may be corrected if disableness is prevented. Mental retardation was not present in every case and heart disease was diagnosed in only one case, although heart catheterism was practiced in 50% of all cases. Since heart lesion is the main cause of death, it should always be investigated. Clinics, x-rays and laboratory should always be the basis of the diagnosis.     

Calcium transients in single myocytes and membranous ultrastructures during the development of cardiac hypertrophy and heart failure in rats

1. We examined changes in intracellular calcium transients of separated single myocytes from the right ventricle (RV) of the rat heart during the change from adaptation to maladaptation in response to a pressure overload. 2. Right ventricular hypertrophy (RVH) secondary to pulmonary hypertension was induced by a subcutaneous injection of monocrotaline. Developed tensions of the RV-free wall were decreased as RVH progressed. Single myocytes were separated from the RV during different stages of RVH. Fura-2/AM-loaded cells were field stimulated, and changes in calcium transients were measured by Olympus OSP-3 system. We also examined membranous ultrastructures (sarcoplasmic reticulum, mitochondria, surface caveolae) involved in calcium metabolism in the hearts using scanning electron microscopy. 3. We observed characteristic changes in calcium transients during the change from adaptation to maladaptation, and also found that one parameter (amplitude) of calcium transients appeared to be correlated with the changes in the number of sarcoplasmic reticulum. 4. These results provided some insights into the mechanism of calcium handling of hypertrophied heart in response to a pressure overload from adaptation to maladaptation especially when stimulatory frequency was high, and suggested that heart rate control is a very important factor for the treatment of patients with congestive heart failure.     

Rapid overdrive pacing of refractory tachyarrhythmias in patients after open-heart surgery

The efficacy of rapid ventricular pacemaker overdrive in the treatment of supraventricular and ventricular tachyarrhythmias is presented as a new approach to the management of these rhythm disorders inpatients after cardiac surgery. This mode of therapy is exemplified in the control of heart rate and return of normal sinus rhythm in patients with both types of tachyarrhythmias refractory to conventional antiarrhythmic agents. In addition, the pathogenesis and mechanisms of pacemaker overdrive in termination these rhythm disturbances are delineated.     

Adaptation of the denervated heart to physical effort

In a transplanted heart, increased stroke volume secondary to the Starling mechanism and increased heart rate and contractility secondary to noradrenaline effect appear sequentially whereas they appear simultaneously in normal innervated heart. Cardiac output adaptation at exercise is thus delayed and responsible for metabolic acidosis and abnormally high exercise ventilation. Moreover, stroke volume adaptation to exercise is compromised by abnormally high right and left afterload and by systolic and diastolic impairement of the ventricular function related with chronic rejections' episodes.     

Dietary risk factors for colon cancer in a low-risk population

Spontaneous EEG was registered under different activity conditions in 26 volunteers. The EEG synchronisation parameters were compared with the geomagnetic and solar activity on the day of experiment. A positive correlation of the EEG data with the geomagnetic activity was revealed, being most obvious in the frontal and central areas. A negative correlation between some local EEG synchronisation parameters and different indices of the solar activity, was also revealed. The degree of synchronisation of the spontaneous EEG seems to reflect sensitivity of the human nervous system to the Earth's magnetic field. A stressor response to strong short-term disturbances in the geomagnetic field reveals itself in the form of enhancement of the EEG global synchronisation. A sedative effect of slow magnetic oscillations is locally revealed in the parameters of the EEG synchronisation within the left hemisphere as well as the interhemisphere synchronisation.     

Variations of cardiac cycle length in patients with coronary heart disease before and after aortic coronary bypass surgery

It is well known that variations in cardiac cycle length or heart rates may be used for noninvasive evaluation of autonomic cardiovascular control. The investigation uses an original procedure. The data for analysis of cardiac cycle length variations (CCLV) are those obtained regularly at follow-up intervals, random 24-hour Holter 2-lead ECG recordings for 5 sec, and simultaneously calculated continuous sequence of mean heart rate. With the procedure, the correlations of CCLV with the parameters reflecting the early postoperative status of patients with CHD, including acute myocardial infarction, acute heart failure, rhythm and conduction disturbances, as well as age, operative stress, concurrent diseases. The findings are of both diagnostic and predictive value at subsequent stages of CHD treatment.     

"The athlete's heart": most common electrocardiographic findings

The morphological and functional cardiac adaptations induced by physical training may be reflected in several athlete's electrocardiographic variants. Rhythm and heart rate disturbances are the most common findings, and sinus bradycardia is the most frequent adaptation. Non-specific intraventricular conduction delay and incomplete right bundle branch block are also frequent, but other bundle branch and fascicular blocks are extremely rare. While the atrioventricular conduction may be prolonged, the occurrence of first degree and type I second degree atrioventricular blocks depends on the individual's susceptibility. Advanced second and third degree atrioventricular blocks are exceptional, and when present, the possibility of underlying heart disease must be excluded. High QRS voltage is more frequent in male athletes, but its correlation with left ventricular hypertrophy is low. The ST segment elevation in the so called "early repolarization" pattern is typical of the athlete's electrocardiogram. Vagotonic or high T wave voltages and U waves are also frequent when sinus bradycardia is present. Tachyarrhythmias and increased automatism arrhythmias are rare and usually benign. The increased vagal tone is responsible for the suppression of the physiological and ectopic pacemakers. While Wolff-Parkinson-White syndrome per se does not exclude an athlete from sports activity, the risk of a sudden death makes it mandatory to perform an exhaustive cardiac evaluation. We may conclude that no sport can be considered arrhythmogenic or as a predisposing factor for malignant ventricular arrhythmias.     

Adverse effects of neuromuscular blockers and their antagonists

Among all the drugs used for general anaesthesia, neuromuscular blockers appear to play a prominent role in the incidence of severe adverse reactions. It now seems likely that most serious adverse drug reactions occurring during anaesthesia are immunological in type. The frequency of life-threatening anaphylactic or anaphylactoid reactions occurring during anaesthesia has been estimated to be between 1 in 1000 and 1 in 25,000 anaesthetic procedures, with the neuromuscular blockers being involved in 80% of cases. The mortality from such serious reactions is reported to be in the range of 3.4 to 6%. The highly immunogenic drug, suxamethonium chloride (succinylcholine), was found to be the most hazardous agent. Drug-specific immunoglobulin E antibodies to suxamethonium chloride and other neuromuscular blockers have been demonstrated. This sensitivity to neuromuscular blockers seems to be a long-lasting phenomenon. During anaesthesia, the clinical features of an allergic reaction are often masked. Tachycardia and circulatory collapse may be the only signs of an allergic reaction, and they are easily misdiagnosed. Bronchospasm is reported to be present in about 40% of cases. Successful management of these patients includes stabilisation during the acute reaction and avoidance of future reactions. The latter is based on the identification of the causative drug and potentially cross-reacting compounds. The use of suxamethonium chloride is associated with many other adverse effects, such as fasciculations, myalgia, potassium release, changes in the heart rate, increases in intragastric and intraocular pressures, and malignant hyperthermia. Because of the dangers of hyperkalaemic cardiac arrest after suxamethonium chloride administration in children with unrecognised muscular dystrophy, there have now been moves to limit the use of this drug in children. Although neuromuscular blockers are designed to specifically block nicotinic cholinergic receptors at the neuromuscular junction, many bind to muscarinic cholinergic receptors on ganglia and smooth muscle, and alter parasympathetically mediated heart rate and airway calibre. Most benzylisoquinolinium muscle relaxants can induce histamine release, especially when they are administered rapidly, which can lead to disturbances of cardiovascular function. In addition, nondepolarising neuromuscular blockers have been implicated in causing generalised weakness following their long term administration to patients on an intensive care unit. The problem with these adverse drug reactions is their unpredictable nature. Therefore, prompt recognition with appropriate therapy can help to improve the outcome.     

A model for the role of carbon on carbochlorination of TiO2

The carbochlorination of TiO₂ is characterized by two successive reaction stages, named the first and the second stage. In both stages, reaction rate increases as carbon mass fraction increases. This kinetic effect of carbon was interpreted on the basis of a model developed to describe the rate of each reaction stage as a function of carbon mass fraction in TiO₂-C powder mixture. The model considers, for both reaction stages, two global steps: [I] the formation of gaseous intermediates at the carbon surface and [II] the reaction of these intermediates with TiO₂ to form the reaction products. The mathematical treatment from these steps involves the adaptation of the general model applied to catalytic gas-solid reactions. The first reaction stage occurs, for high carbon contents, under strong external chlorine transport control and, for low enough carbon content, under internal mixed control. The second reaction stage occurs out of external gaseous influence and a net chemical control operates, both at low temperatures and for the lowest carbon content. The intrinsic activation energies for the first and second reaction stages are 40 and 117 kJ-mol⁻¹, respectively.     

Ulcero-multilating acropathy

A case of a 46 years old male suffering from chronic sensory neuropathy is reported. The symptoms consisted of superficial and deep sensory disturbances, and bilateral trophic plantar ulcerations with osteolysis, resulting in a deformity of the feet. There was an increased sweating of the distal portions of the four limbs, and a delayed adaptation of blood pressure and heart frequency to postural changes. CSF aminoacids were all increased except taurine, which was markedly descreased. An increased blood flow in lower extremities was demonstrated angiographically. The possibilities of pharmacological and surgical treatment raised by the hemodynamic hypothesis of BUREAU and BARRIERE (1957) are discussed.     

Clinical and haemodynamic correlates of heart rate variability in children with congenital heart disease

Heart rate variability (HRV) represents a noninvasive parameter for studying the autonomic control of the heart. Cardiac patients have a complex autonomic disturbance. The relation of HRV to this abnormality in children with congenital heart disease (CHD) has not yet been examined. The present study examined HRV indices from 24 h Holter recordings in 258 children with an operated or non-operated CHD, to determine their differences as an indicator of the severity of heart disease. The latter was defined clinically as New York Heart Association (NYHA) functional classes I to IV and haemodynamically by invasive parameters. Five time-domain measures (SDNN, SDNNi, SDANNi, rMSSD and pNN50) and three frequency-domain measures (LF, HF and balance LF/HF) were compared with normal ranges. HRV was reduced in children with CHD, except in patients of NYHA class I. The level of reduction depended on the NYHA functional class. None of the measures was significantly related to haemodynamic data. CONCLUSION: Heart rate variability is reduced in children with Congenital heart disease depending on the functional limitation but not on haemodynamic disturbances. Heart rate variability indices are sensitive markers of the clinical state.     

Protein kinase C alterations in aortic vascular smooth muscle cells from rats with cirrhosis

It was found that the frequency of extreme situations (traumas, deaths, sudden diseases) in miners working in Spitsbergen mines (74 degree N) correlates well with heliogeomagnetic activity (local magnetic disturbances, solar proton flashes). It was shown that in winter, both an enhanced and an extremely low level of magnetic activity can affect the occurrence of extreme situations. The results obtained can be used for predicting and reducing the frequency of extreme events in the zone of the polar cap during geomagnetic disturbances.     

The dynamic regulation of myocardial oxidative phosphorylation: analysis of the response time of oxygen consumption

Although usually steady-state fluxes and metabolite levels are assessed for the study of metabolic regulation, much can be learned from studying the transient response during quick changes of an input to the system. To this end we study the transient response of O2 consumption in the heart during steps in heart rate. The time course is characterized by the mean response time of O2 consumption which is the first statistical moment of the impulse response function of the system (for mono-exponential responses equal to the time constant). The time course of O2 uptake during quick changes is measured with O2 electrodes in the arterial perfusate and venous effluent of the heart, but the venous signal is delayed with respect to O2 consumption in the mitochondria due to O2 diffusion and vascular transport. We correct for this transport delay by using the mass balance of O2, with all terms (e.g. O2 consumption and vascular O2 transport) taken as function of time. Integration of this mass balance over the duration of the response yields a relation between the mean transit time for O2 and changes in cardiac O2 content. Experimental data on the response times of venous [O2] during step changes in arterial [O2] or in perfusion flow are used to calculate the transport time between mitochondria and the venous O2 electrode. By subtracting the transport time from the response time measured in the venous outflow the mean response time of mitochondrial O2 consumption (tmito) to the step in heart rate is obtained. In isolated rabbit heart we found that tmito to heart rate steps is 4-12 s at 37 degrees C. This means that oxidative phosphorylation responds to changing ATP hydrolysis with some delay, so that the phosphocreatine levels in the heart must be decreased, at least in the early stages after an increase in cardiac ATP hydrolysis. Changes in ADP and inorganic phosphate (Pi) thus play a role in regulating the dynamic adaptation of oxidative phosphorylation, although most steady state NMR measurements in the heart had suggested that ADP and Pi do not change. Indeed, we found with 31P-NMR spectroscopy that phosphocreatine (PCr) and Pi change in the first seconds after a quick change in ATP hydrolysis, but remarkably they do this significantly faster (time constant approximately 2.5 s) than mitochondrial O2 consumption (time constant 12 s). Although it is quite likely that other factors besides ADP and Pi regulate cardiac oxidative phosphorylation, a fascinating alternative explanation is that the first changes in PCr measured with NMR spectroscopy took exclusively place in or near the myofibrils, and that a metabolic wave must then travel with some delay to the mitochondria to stimulate oxidative phosphorylation. The tmito slows with falling temperature, intracellular acidosis, and sometimes also during reperfusion following ischemia and with decreased mitochondrial aerobic capacity. In conclusion, the study of the dynamic adaptation of cardiac oxidative phosphorylation to demand using the mean response time of cardiac mitochondrial O2 consumption is a very valuable tool to investigate the regulation of cardiac mitochondrial energy metabolism in health and disease.