BIO-ASSAY OF CIRCULATING RENIN-LIKE PRESSOR MATERIAL BY ISOVOLEMIC CROSS CIRCULATION.
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Angiotensins↗
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Effective cross-circulation technique of venoarterial bypass for differential hypoxia condition.
We examined a new technique of cross-circulation (CC) venoarterial bypass (VAB) with femoral arterial perfusion and superior vena cava drainage through a long femoral venous cannula. Six adult mongrel dogs weighing 15 to 20 kg underwent the CC-VAB with oxygenation after introduction of respiratory failure (RF). The flow of the CC-VAB was maintained at half the level of the control cardiac output, and the hemodynamic parameters were monitored. To evaluate hypoxia in the upper body, the arterial partial pressure of oxygen (PaO2 [mm Hg]) in the carotid artery and the venous saturation of oxygen (SvO2 [%]) in the pulmonary artery were measured during control, RF, standard VAB, and CC-VAB conditions. The PaO2 decreased significantly after the introduction of RF (41.7 +/- 12.4), and it returned to normal levels only after CC-VAB (151.2 +/- 24.5, p < 0.05). The SvO2 during CC-VAB (98.6 +/- 2.1) was significantly higher than that during VAB without CC (53.5 +/- 3.4, p < 0.05). These results suggest that this cross-circulation technique could be applied to patients with differential hypoxia during femoral VAB with oxygenation or percutaneous cardiopulmonary support (PCPS).
Analysis of Variance↗
Anaesthetic management of thoracopagus twins with complex cyanotic heart disease for cardiac assessment: special considerations related to ventilation and cross-circulation.
We describe the anaesthetic management of a pair of thoracopagus twins of 14 months of age undergoing complex cardiac evaluation. Synchronous ventilation of the twins, needed for the ECG-gated magnetic resonance imaging-angiography, was achieved through a Carlens (Y) adaptor during procedures and transport. The complex logistical implications are obvious. We also describe the first use of bispectral index monitor for detection of cross-circulation in conjoint twins.
Anesthesia, General↗
An experimental study of cross-circulation for cardiopulmonary bypass in dogs.
Cardiopulmonary bypass using cross-circulation was evaluated in dogs. In eight experiments a greyhound (the donor) was used to perfuse a small mongrel dog (the recipient). Recipients averaged 40 per cent of the donor's weight. Total cardiopulmonary bypass was successfully established in all eight experiments and maintained for 60 to 90 minutes. Haemodynamic values (mean arterial pressure, central venous pressure, cardiac output) and arterial blood gas tensions in the recipient and donor dogs remained at near-baseline levels for the duration of cardiopulmonary bypass. Seven of the eight recipient dogs were successfully weaned from cardiopulmonary bypass at the end of the procedure.
Animals↗
Problems in treating experimentally induced acute hepatic failure by hemoperfusion or cross circulation.
Acute hepatic failure was induced in rats by galactosamine injection intraperitoneally (1 gm per kg). Twenty-four hours later rats were treated by hemoperfusion (HP) over encapsulated sorbents: cellulose acetate-coated charcoal, polyelectrolyte-coated XAD4, a combination of both, or cross circulation with a healthy donor. Compared with control treatment (prevention of hypoglycemia by glucose infusion), the survival rate was not improved by HP or cross circulation: controls 19% vs. treated animals 0 to 17%. Extension of duration or increased frequency of HP gave the same survival rates. Computer simulation based on zero-order introduction of a possible toxin into a two-compartment model shows that HP up to 5 hr per day is not able to clear the body effectively from the assumed toxin if its partition coefficient exceeds a value of 50.
Animals↗
Ventilatory responses during electrically induced muscular work in anesthetized dogs, after both deafferentation and cross circulation of hindlimbs.
1. The role of the neural afferent component from moving limbs during exercise hyperpnea has been studied in dogs. The influence of neural and humoral effects was evaluated by dorsal root section and limb cross-circulation. 2. Respiratory minute volume (Ve), frequency (f), tidal volume (VT) and oxygen consumption (VO2) were measured in anesthetized dogs submitted to light electrically-induced exercise (ventral root stimulation of L6 or L7), both before and after deafferentation. 3. In control experiments the increase of respiratory minute volume (Ve) was directly proportional to VO2, and primarily due to changes in frequency. After dorsal root section (L1 to S1), VO2 increased, but no significant changes were observed in the other respiratory parameters. 4. In contrast to the deafferentation experiments, no changes were detected either in Ve or in f during exercise in the cross-circulation experiments. 5. It is concluded that during light exercise reflexes generated by moving limbs are important for triggering the exercise tachypneic response.
Anesthesia, Intravenous↗
Cross-circulation studies on the influence of hypoxia and hypoxaemia on neuro-epithelial bodies in young rabbits.
The reactions of the previously described neuro-epithelial bodies (NEB)(Lauweryns et al., 1969, 1970, 1972a, b, 1973a, b, c 1974, 1975) in young rabbits to: (1) hypoxia with normoxaemia in the arteria pulmonalis on the one hand, and (2) hypoxaemia in the arteria pulmonalis with normoxic aeration on the other hand, has been investigated by means of cross-circulation experiments and light microscopical, electron microscopical and morphometrical techniques. Hypoxically aerated young rabbits, which received normoxaemic blood in their arteria pulmonalis from a donor rabbit by means of an arterio-arterial cross-circulation with mutal exchange transfusion, revealed an increased exocytosis of the dense-core vesicles of their NEB. Normoxically aerated young rabbits which received hypoxaemic blood in an identical manner, did not exhibit an increased exocytosis. It is concluded that the NEB apparently react directly to the hypoxia of the inhaled air and not to the hypoxaemia of the pulmonary blood. By the release of serotonin and a polypeptide substance, they may produce a local vasoconstriction in hypoxically aerated lung areas, enabling an intrapulmonary regulation of the V/Q ratio. This is regarded as additional proof that the NEB--while being modulated by the CNS--probably are intrapulmonary chemoreceptors with local secretory activities, reacting to the composition of the inhaled air.
Animals↗
The effects of cross-circulation and charcoal hemoperfusion on adenylate energy charge of the remnant liver after major hepatic resection.
The effect of liver support on the adenylate energy charge (ATP + 1/2 ADP) / (ATP + ADP + AMP) of the remnant liver after major hepatic resection was studied in rabbits. The present study emphasizes the principle of the use of homologous or heterologous liver for preventing the decrease in the energy charge of the remnant liver after major hepatic resection. The energy charge level provides the cell with a very sensitive intracellular control mechanism. Regulatory enzymes from biosynthetic sequences exhibit very little activity at low levels of energy charge, and their activities increase sharply at high charge values. The energy charge level of the remnant liver maximally decreased from the normal level of 0.843 to 0.767 at 24 hours after 70% hepatectomy. The energy charge level increased from 0.767 to 0.828 after one hour of cross-circulation of systemic blood between the 24-hour, 70% hepatectomized rabbit and a normal rabbit. An increase from 0.767 to 0.801 also occurred after one hour of charcoal hemoperfusion. Although either means of liver support serves to restore energy charge levels, the above results suggest that cross-circulation may be more effective than charcoal hemoperfusion for biosynthesis in the regenerative processes of the remnant liver.
Adenosine Diphosphate↗
Perfusion of the pancreas by means of a crossed circulation.
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Cross Circulation↗
Efficacies of whole blood and plasma cross circulation on galactosamine induced hepatic failure rats.
Galactosamine induced hepatic failure rats were treated by whole blood and plasma cross circulation. While no significant improvement in survival rate was achieved by means of these 2 procedures, oxygen consumption in state 3 and ATP synthesis of mitochondrial function were significantly improved as compared to the sham circulation groups. Maintenance of mitochondrial functions as by extracorporeal perfusion techniques may be advantageous in acute hepatic failure.
Animals↗
Evaluation of cross-circulation through circle of Willis using an ultrasonic Doppler technique. Part I. Comparison between blood flow velocity by ultrasonic Doppler flowmetry and angiogram.
In 24 patients with cerebrovascular disease and 6 without organic brain lesions, the increased velocity of blood flow in both the internal carotid and vertebral arteries during a contralateral carotid compression was compared with the angiographic appearance of the circle of Willis. The flow velocity was measured using ultrasonic Doppler flowmetry. It was not possible to investigate fully the relationship between the increase of velocity of blood flow in the internal carotid artery and the anatomical variations of the circle of Willis, specifically the anterior cerebral and communicating arteries. The velocity of flow in the patients with an aplastic proximal portion of the anterior cerebral artery showed no increase. There were no differences in the increase of velocity of flow in the vertebral artery in patients with hypoplastic, normal and fetal posterior communicating arteries. It is considered that although anatomical variations of the circle vessels influence the cross-circulation via the circle of Willis, peripheral vascular factors distal to the circle also play an important role in the quantity of cross-circulation through the circle.
Adolescent↗
An X-ray diffraction study of the cross-circulated canine heart.
1. The equatorial X-ray diffraction pattern was recorded from a papillary muscle of a cross-circulated canine heart at different phases of the cardiac cycle. The intensity ratio of the 1, 0 and the 1, 1 reflexions (I1, o/I1,1) was 0-79 in the systolic phase and 1-19 in the diastolic phase. 2. Using the intensity ratio obtained, the approximate proportion of the myosin projections present in the vicinity of the thin filaments was calculated. This was 70-71% in the systolic phase and 51-52% in the diastolic phase of the total myosin projections. 3. The peak systolic tension was roughly proportional to the proportion of the projections present in the vicinity of the thin filaments during systole. 4. The projections which stayed in the vicinity of the thin filaments during diastole did not produce significant contractile force.
Animals↗
Intrarenal hemodynamics in cross-circulated hypervolemic and isovolemic rats.
The microsphere technique was used to measure renal blood flow and intrarenal flow distribution in cross-circulated pairs of rats. One rat of each pair was made hypervolemic by infusion of blood (2.3% of body weight), followed by intravenous reinfusion to urine to maintain intravascular expansion. The other rat of each pair, which also was urine-reinfused, was kept isvolemic throughout the experiment. As shown previously, blood infusion resulted in a large diuretic and natriuretic response in the hypervolemic partner, while a smaller but statistically significant response occurred in the isovolemic partner. Total renal blood flow did not change in the expanded rats and fell slightly but not significantly in the nonexpanded ones. Blood volume expansion was associated with a significant shift in microsphere concentration from outer to inner cortex. This shift was not, however, correlated with the magnitude of the renal response. The transferred natriuresis in isovolemic partners was not associated with any change in microsphere distribution. We conclude therefore, that redistribution of blood flow to the inner cortex, although a feature of intravascular expansion, is not the primary determinant of volume natriuresis. In addition, the natriuretic activity which develops in the blood of hypervolemic rats can reduce sodium reabsorption in isovolemic rats without intrarenal hemodynamic changes.
Animals↗
A possible purinergic mechanism for reactive ischemia in isolated, cross-circulated rat kidney.
The isolated kidney of the recipient rat was perfused at a fixed flow rate with blood from a donor by a cross-circulation technique. The renal vasculature responded to the release of arterial occlusion with vasoconstriction, the magnitude of which was increased with increase in the duration of occlusion. ATP, ADP, AMP, adenosine, noradrenaline and 5-HT injected into the renal artery induced a prominent vasoconstriction; IMP and inosine had only a weak vasoconstrictor effect even in large doses. Theophylline reduced the vasoconstriction in response to arterial occlusion and to ATP and adenosine but did not affect that produced by noradrenaline or 5-HT. This suggests that adenine compounds, particularly adenosine, may play a role in the genesis of reactive vasoconstriction after arterial occlusion in the isolated rat kidney.
Animals↗
[Cross circulation (CC) as an assist method for canine orthotopic cardiac transplantation--estimation of usefulness judging from intra- and postoperative hematological and biochemical examinations].
We employed cross circulation (CC) as an assist method for canine orthotopic cardiac transplantation in 8 dogs to obtain long term survivals. Hematological and biochemical examinations were performed intra- and postoperatively, to estimate usefulness of CC. The support dog weighted about 3 times as much as the recipient dog. Using different anesthesia, the systolic pressure of the support dog and the pressure gradient between the support and recipient were kept above 150 mmHg and 50 mmHg, respectively. Cyclosporin and prednisolone were administered for immunosuppressive therapy. All could be extubated on the 1st to 3rd postoperative day, and 6 survived more than 2 weeks. During the operation under CC, changes of LDH and lactic acid were much less, no free hemoglobin was detected, and total protein and hematocrit remained well compared with operation under heart-lung machines. CRK, CPKMB, GOT and GPT increased shortly after operation, but returned to the preoperative values within 2 weeks. In CC, owing to avoidance from mechanical destruction of red blood cells, coagulation disorders and hemodilution, hemolysis and hemorrhage could be decreased, and oncotic pressure remained well, and no severe damage occurred in the recipient organs. Thus, CC is useful as an assist method for canine orthotopic cardiac transplantation.
Animals↗
Myocardial microvascular perfusion after transfusion of liposome-encapsulated hemoglobin evaluated in cross-circulated rat hearts using tracer digital radiography.
The effect of hemodilution with Neo Red Cell (NRC, liposome-encapsulated hemoglobin) on myocardial perfusion was evaluated in cross-circulated rat hearts under 300-bpm pacing and 100-mmHg perfusion pressure. In NRC-transfused hearts (n = 5), NRC volume fraction and hematocrit were 9% +/- 3% and 22% +/- 4%, respectively; the latter decreased from 43% +/- 3% before NRC transfusion. Coronary perfusion rate and left ventricular isovolemic developed pressure increased after NRC transfusion to 4.6 +/- 1.0 ml/min/g and 127 +/- 32 mmHg from basal values of 2.5 +/- 0.3 ml/min/g and 115 +/- 28 mmHg, respectively. In contrast, the flow increase during reperfusion following 30-s flow cessation decreased from 74% +/- 24% to 64% +/- 24%. The arteriovenous difference in O2 saturation was slightly higher after NRC transfusion. Within-layer regional flow distributions from subepicardium to subendocardium assessed by tracer digital radiography (100-microm resolution) showed that coefficients of variation of flows in 400 x 400-microm regions were 0.41 +/- 0.10 in NRC-transfused hearts and 0.54 +/- 0.11 in nontransfused hearts (n = 5); i.e., the myocardial flow distribution was more uniform in NRC-transfused hearts. These results suggest that NRC is superior to erythrocytes in terms of the homogenization of O2 delivery, indicating its potential therapeutic value in myocardial microcirculatory failure.
Animals↗
Cardiovascular effects of ZSY-27 [5-methyl-6-(4-pyridinyl)-2H-1,4-thiazine-3(4H)-one X hydrochloride] in the dog cross-circulated atrial preparation.
A new cardiotonic compound, 5-methyl-6-(4-pyridinyl)-2H-1,4-thiazine-3(4H)-one X hydrochloride (ZSY-27), was investigated in cross-circulated dog atrial muscle preparations. When ZSY-27 was intravenously administered to the donor dog, a dose-dependent depressor effect with slight sinus tachycardia was induced in the donor dog. At the same time, a significant dose-dependent increase in developed tension was usually observed in an isolated atrium perfused with donor's arterial blood, but there were no significant changes in sinus cycle length and sinoatrial conduction time. The ZSY-27-induced positive inotropic effect was not significantly influenced by treatment with propranolol in doses which completely inhibited norepinephrine-induced positive chronotropic and inotropic effects. When ZSY-27 was injected into the cannulated sinus node artery of the isolated atrium, dose dependent positive chronotropic and inotropic effects were induced. The dominant increases in developed tension by ZSY-27 were similar to effects of other phosphodiesterase inhibitors, such as papaverine and aminophylline. From these results, it is concluded that ZSY-27 has non-adrenergic, cardiotonic properties with a depressor effect.
Aminophylline↗
Positive chronotropic and inotropic effects of pimobendan (UD-CG 115 BS) in isolated, cross-circulated canine heart preparations.
The effects of pimobendan on the sinus node pacemaker activity and atrial contractility and on the left ventricular contractility were investigated in the isolated, cross-circulated right atrial and left ventricular preparations of the dog. Pimobendan, at a dose range of 1 to 1,000 nmol, injected into the sinus node artery of the isolated atrium, induced dose-dependent positive inotropic and chronotropic responses. At the same doses, it also induced dose-dependent increases in the left ventricular contractile force, similar to those in the atrial one, although the norepinephrine (NE)- and isoproterenol-induced positive inotropic effects in the ventricles were less than those in the atria. The positive cardiac effects were not inhibited by propranolol but they were depressed by intramural vagal nerve stimulation. These results suggest that pimobendan increases left ventricular contractility more effectively than atrial contractility in comparison with a beta-adrenoceptor agonist and that the positive cardiac effects of pimobendan were partially induced by a phosphodiesterase inhibition but not by a beta-adrenoceptor activation in the dog heart. When pimobendan, at a dose of 10 to 1,000 micrograms/kg, was cumulatively administered into the jugular vein of the support dog, a decrease in arterial blood pressure and an increase in heart rate were dose-dependently observed in the support dog. Half a minute after administration, the positive inotropic and chronotropic responses were induced in the isolated atrium in a dose-related manner. The pimobendan-induced positive cardiac effects were not inhibited by i.v. administration of propranolol, whereas the isosorbide dinitrate-induced positive chronotropic effects were significantly inhibited. These results indicate that pimobendan directly increases cardiac contractility and heart rate with vasodilatation in anesthetized dogs.
Adrenergic beta-Antagonists↗