Changes of the electrical heart field and hemodynamic parameters in the 34th to 40th weeks of pregnancy and after delivery

We have studied changes of the electrical heart field resulting from the changed spatial position of the heart during the last period of pregnancy in healthy women. This was suggested to be a good model of electrocardiographic changes that could be found on patients suffering from obesity. The measured parameters of the electrical heart field were compared with hemodynamic parameters before and after delivery in the group of non-obese women with physiological pregnancy and in a group of healthy non-obese and non-pregnant women. Several significant changes of the electrical heart field were detected in the late pregnancy: increased heart rate, shortening of A-V conductance, prolongation of QT interval normalised for the heart rate and changes in the ventricular depolarisation and repolarisation patterns. Some of these changes are not fully restored in 4 days after delivery. Moreover, we have found an increased pump function of the left ventricle accompanied by decreased peripheral resistance in the group of pregnant women. Increased pump function was partially restored after delivery, peripheral resistance was not only restored, but it overshot to increased values. Persisting elevated heart rate with increased peripheral resistance suggested increased sympathetic activity after birth. Only some changes of electrical heart field could be explained by changed spatial arrangement of the chest organs during pregnancy and they must be considered in a complex consequence with changes in regulatory mechanisms. Received: 13 March 2001 / Accepted: 2 October 2001     

Prevention of heart failure by adapting the body to high-altitude hypoxia]

The impact of adaptation of the body to various high-altitude levels was thoroughly studied in 355 Chinchilla rabbits. It was found that adaptation of the body to high-altitude conditions prevents to a great measure a complex of phenomena specific to heart failure: disturbed myocardial RNA metabolism, reduced cardiac volume, increased mass of circulating blood, destructive myocardial changes, etc. Adaptation to high-altitude hypoxia is conducive to resistance of the heart to additional load and may be used in the prevention of heart failure as well as in the prevention of heart diseases and circulatory disorders.     

Mechanism of action of mercury on sperm morphology, adenosine triphosphate content, and motility in Perca fluviatilis (Percidae; Teleostei)

The main objectives of the present study were to investigate the performance of mercury chloride (HgCl2 ) on sperm function and structure, identify sites of action of HgCl2 , and investigate the mechanism of action of HgCl2 on fish (Perca fluviatilis L.) spermatozoa. Direct exposure of nonincubated sperm decreased sperm motility and velocity in a dose-dependent manner and was totally suppressed at 250?μM HgCl2 . Adenosine-5'-triphosphate (ATP) content of sperm after activation in an activation medium (AM) containing more than 25?μM HgCl2 did not differ compared with nonactivated sperm. Motility and velocity of demembranated sperm decreased after activation in an AM containing 62?μM HgCl2 , and was totally suppressed at 250?μM HgCl2 . Incubation of sperm in an immobilizing medium (IM) containing HgCl2 enhanced HgCl2 effects after sperm activation in an AM containing HgCl2 . Sperm motility of incubated sperm in an IM without HgCl2 was totally suppressed at 125?μM HgCl2 after 3?h incubation. In case of incubated sperm in an IM containing HgCl2 , sperm motility was totally suppressed at 31?μM HgCl2 . Adenosine-5'-triphosphate content of sperm was significantly lower in an IM containing HgCl2 greater than 3?μM compared with those of the control (no HgCl2 ) and lower HgCl2 concentrations. Damage to the plasma membrane and axoneme were observed in sperm incubated in an IM containing HgCl2 compared with the control, when HgCl2 concentration and incubation time increased. In conclusion, HgCl2 acts on sperm through disruption of function of the plasma membrane, axoneme, and ATP content.     

Ischemic Postconditioning and Nitric Oxide Administration Failed to Confer Protective Effects in a Porcine Model of Extracorporeal Cardiopulmonary Resuscitation

The protective effects of ischemic postconditioning (IPC) and nitric oxide (NO) administration have been demonstrated in several ischemic scenarios. However, current evidence regarding the effect of IPC and NO in extracorporeal cardiopulmonary resuscitation remains lacking. Fifteen female swine (body weight 45 kg) underwent veno‐arterial extracorporeal membrane oxygenation (ECMO) implantation; cardiac arrest‐ventricular fibrillation was induced by rapid ventricular pacing. After 20 min of cardiac arrest, blood flow was restored by increasing the ECMO flow rate to 4.5 L/min. The animals (five per group) were then randomly assigned to receive IPC (three cycles of 3 min ischemia and reperfusion), NO (80 ppm via oxygenator), or mild hypothermia (HT; 33.0°C). Cerebral oximetry and aortic blood pressure were monitored continuously. After 90 min of reperfusion, blood samples were drawn for the measurement of troponin I, myoglobin, creatine‐phosphokinase, alanine aminotransferase, neuron‐specific enolase, cystatin C, and reactive oxygen metabolite (ROM) levels. Significantly higher blood pressure and cerebral oxygen saturation values were observed in the HT group compared with the IPC and NO groups (P < 0.05). The levels of troponin I, myoglobin, creatine phosphokinase, and alanine aminotransferase were significantly lower in the HT group (P < 0.05); levels of neuron‐specific enolase, cystatin C, and ROM were not significantly different. IPC and NO were comparable in all monitored parameters. The results of the present study indicate that IPC and NO administration are not superior interventions to HT for the maintenance of blood pressure, cerebral oxygenation, organ protection, and suppression of oxidative stress following extracorporeal cardiopulmonary resuscitation.     

Outline of the physiology and pathophysiology of the senses

Sense organs are considered as systems that detect information from the outer and inner environment and transfer it to the central nervous system where it is processed by a series of brain structures which make it the basis for the conscious interpretation of the surrounding world. The work discusses sense receptors as nerve structures recording specific forms of energy in our surroundings and their key function, so-called transduction, i.e. the conversion of energy of a given modality to electrical energy of the action potentials of afferent nerves. The information encoded in this form is then brought together in subcortical (thalamic) centres for processing and synthesis in the cerebral cortex. The specific implementation of this general framework is given for each of the main sense systems: somatosensory, sight, hearing, vestibular, taste and smell. The basic disorders of sense perception, their usual aetiologies and the pathogenic mechanisms responsible for their development and symptoms are outlined briefly.     

Coronary versus carotid blood flow and coronary perfusion pressure in a pig model of prolonged cardiac arrest treated by different modes of venoarterial ECMO and intraaortic balloon counterpulsation

ABSTRACT: INTRODUCTION: Extracorporeal membrane oxygenation (ECMO) is increasingly used in cardiac arrest (CA). Adequacy of carotid and coronary blood flows (CaBF, CoBF) and coronary perfusion pressure (CoPP) in ECMO treated CA is not well established. This study compares femoro-femoral (FF) to femoro-subclavian (FS) ECMO and intraaortic balloon counterpulsation (IABP) contribution based on CaBF, CoBF, CoPP, myocardial and brain oxygenation in experimental CA managed by ECMO. METHODS: In 11 female pigs (50.3 ± 3.4 kg), CA was randomly treated by FF versus FS ECMO ± IABP. Animals under general anesthesia had undergone 15 minutes of ventricular fibrillation (VF) with ECMO flow of 5 to 10 mL/kg/min simulating low-flow CA followed by continued VF with ECMO flow of 100 mL/kg/min. CaBF and CoBF were measured by a Doppler flow wire, cerebral and peripheral oxygenation by near infrared spectroscopy. CoPP, myocardial oxygen metabolism and resuscitability were determined. RESULTS: CaBF reached values > 80% of baseline in all regimens. CoBF > 80% was reached only by the FF ECMO, 90.0% (66.1, 98.6). Addition of IABP to FF ECMO decreased CoBF to 60.7% (55.1, 86.2) of baseline, P = 0.004. FS ECMO produced 70.0% (49.1, 113.2) of baseline CoBF, significantly lower than FF, P = 0.039. Addition of IABP to FS did not change the CoBF; however, it provided significantly higher flow, 76.7% (71.9, 111.2) of baseline, compared to FF + IABP, P = 0.026. Both brain and peripheral regional oxygen saturations decreased after induction of CA to 23% (15.0, 32.3) and 34% (23.5, 34.0), respectively, and normalized after ECMO institution. For brain saturations, all regimens reached values exceeding 80% of baseline, none of the comparisons between respective treatment approaches differed significantly. After a decline to 15 mmHg (9.5, 20.8) during CA, CoPP gradually rose with time to 68 mmHg (43.3, 84.0), P = 0 .003, with best recovery on FF ECMO. Resuscitability of the animals was high, both 5 and 60 minutes return of spontaneous circulation occured in eight animals (73%). CONCLUSIONS: In a pig model of CA, both FF and FS ECMO assure adequate brain perfusion and oxygenation. FF ECMO offers better CoBF than FS ECMO. Addition of IABP to FF ECMO worsens CoBF. FF ECMO, more than FS ECMO, increases CoPP over time.     

Early vancomycin,amikacin and gentamicin concentrations in pulmonary artery and pulmonary tissue are not affected by VA ECMO (venoarterial extracorporeal membrane oxygenation) in a pig model of prolonged cardiac arrest

BackgroundECMO (extracorporeal membrane oxygenation) is increasingly used in severe hemodynamic compromise and cardiac arrest (CA). Pulmonary infections are frequent in these patients. Venoarterial (VA) ECMO decreases pulmonary blood flow and antibiotic availability in lungs during VA ECMO treated CA is not known. We aimed to assess early vancomycin, amikacin and gentamicin concentrations in the pulmonary artery as well as tracheal aspirate and to determine penetration ratios of these antibiotics to lung tissue in a pig model of VA ECMO treated CA.MethodsTwelve female pigs, body weight 51.5 ± 3.5 kg, were subjected to prolonged CA managed by different modes of VA ECMO. Anesthetized animals underwent 15 min of ventricular fibrillation (VF) followed by continued VF with ECMO flow of 100 mL/kg/min. Immediately after institution of ECMO, a 30 min vancomycin infusion (10 mg/kg) was started and amikacin and gentamicin boluses (7.5 and 3 mg/kg, respectively) were administered. ECMO circuit, aortic, pulmonary arterial, and tracheal aspirate concentrations of antibiotics were measured at 30 and 60 min after administration; penetration ratios were calculated.ResultsAll 30 min antibiotic concentrations and 60 min concentration for gentamicin in the pulmonary artery were no different than the aorta. However, the 60 min pulmonary artery vancomycin and amikacin values were significantly higher than aortic, 19.8 (14.3–21.6) vs. 17.6 (14.2–19.0) mg/L, p = 0.009, and 15.6 mg/L (11.0–18.6) vs. 11.2 (10.4–17.2) mg/L, p = 0.036, respectively. One hour penetration ratios were 18.5% for vancomycin, 34.9% for gentamicin and 38.8% for amikacin.ConclusionIn a pig model of VA ECMO treated prolonged CA, despite diminished pulmonary flow, VA ECMO does not decrease early vancomycin, gentamicin, and amikacin concentrations in pulmonary artery. Within 1 h post administration, antibiotics can be detected in tracheal aspirate in adequate concentrations.