| heart size and maximal cardiac output are limited by the pericardium. | we tested the hypothesis that the pericardium, by restricting heart size, limits maximal cardiac output and oxygen consumption. we studied 15 pigs. five underwent maximal treadmill running before and 14-21 days after thoracotomy and pericardiectomy; these pigs also received sequential volume infusions to determine end-diastolic pressure-dimension relationships. five underwent maximal treadmill running before and 14-21 days after thoracotomy (pericardium undisturbed) to determine the effect of th ... | 1992 | 1481894 |
| ischemia-induced depressed systolic thickening is transiently augmented by remote coronary occlusion. | to determine if ischemia-induced depressed myocardial thickening can be augmented by remote coronary occlusion, posterior wall function (pulsed doppler crystal) was measured before and after left anterior descending coronary artery occlusion in the presence of reduced circumflex coronary artery flow (of sufficient severity to reduce resting function) in an anesthetized open-chest canine preparation in which the circumflex was pump-perfused with carotid arterial blood. left anterior descending co ... | 1992 | 1571984 |
| estimation of total body fluid shifts between plasma and interstitium in man during extracorporeal circulation. | fluid transport between plasma and interstitium during extracorporeal circulation was studied in seven patients undergoing aortocoronary bypass grafting. the absolute shifts in plasma volume during hypothermia were determined as the difference between input and loss of fluid and the changes in blood volume. the change in haemoglobin concentration due to acute haemodilution when starting extracorporeal circulation was used to calculate the absolute blood and plasma volume. the starling equation f ... | 1992 | 1574974 |
| pressure-flow relationships of the pulmonary circulation during endotoxin infusion in intact dogs. | we aimed to characterize the effects of an endotoxin insult (escherichia coli 0127:b8) on the relationships between pulmonary vascular pressure and flow in intact dogs. to achieve this goal, multipoint plots of total pressure gradient, arterial pressure gradient, and venous pressure gradient vs. flow were generated by graded inflation of a right atrial balloon, which was used to vary flow. the partitioning of the total pressure decrease across the pulmonary vasculature (total pressure gradient = ... | 1992 | 1617970 |
| single perturbed beat vs. steady-state beats for assessing systolic function in the isolated heart. | single-beat and steady-state techniques for evaluating end-systolic pressure-volume relationship (espvr) and frank-starling mechanism (fsm) in the crystalloid-perfused isolated rabbit heart were compared. in the single-beat technique, a train of stable isovolumic beats was interrupted with a single perturbed beat that either ejected against various levels of imposed isobaric load (espvr protocol) or beat isovolumically against various levels of end-diastolic volume (v(ed); fsm protocol). in stea ... | 1992 | 1621824 |
| regional contractile performance during acute ischemia in porcine right ventricle. | studies of regional ischemia in the canine left ventricle (lv) have shown augmented systolic segmental shortening in nonischemic regions. to characterize these responses in the right ventricle (rv), acute occlusions of the right coronary artery (rcao) were produced in anesthetized pigs. orthogonal pairs of ultrasonic segment-length crystals were implanted in the mid-rv free wall (ischemic region) and in the outflow tract (nonischemic region). rv pressure-area work loops were generated during inf ... | 1992 | 1636753 |
| renal sodium retention in the nephrotic syndrome. | where do the experiments on rat kidneys exposed to puromycin leave us in attempting to evaluate further the pathophysiology of oedema in human nephrotic syndrome? they cannot be considered conclusive. the arguments favouring an intrinsic abnormality in the kidney as a major factor in sodium retention, rather than this being a secondary response to humoral and neural influences stimulated by changes in actual or perceived plasma volume, would be strengthened by experiments using another animal mo ... | 1991 | 1818554 |
| [turdus merula l. as a proper host of capillaria ovopunctata (nematoda, capillariidae)]. | biometrical analysis of four morphometric characters of male and female specimens of capillaria ovopunctata parasitizing in sturnus vulgaris, erithacus rubecula, turdus philomelos and turdus merula, i.e. length of body, oesophagus, number of stichocytes or length of spicula and vulvar appendage respectively was carried out. it has been proved, that characters of females c. ovopunctata parasitizing in t. merula significantly differ from those of the nematodes found in other hosts. the present and ... | 1991 | 1822042 |
| myocardial metabolic effects of in vivo hydralazine treatment of streptozotocin-diabetic rats. | we determined myocardial pumping capacity, glucose oxidation, and mechanical response to ischemia in streptozotocin-diabetic rats treated for 4 wk with or without hydralazine (0.5 mg/g of chow). plasma triglycerides and cholesterol were decreased 73 and 50%, respectively, in the treated animals. blood glucose levels were greater than 400 mg/100 g in both groups. hearts were perfused in the working configuration with buffer containing 5 mm [u-14c]glucose. starling curves were constructed by incre ... | 1991 | 1996694 |
| [right heart function and endotoxemia in animals]. | we used a chronic instrumented ovine model to investigate right heart function following an endotoxin bolus. primary aim of the experiments was to elucidate the influence of the right heart on the cardiopulmonary system. furthermore, we tried a thromboxane synthetase inhibitor as a therapeutical approach. at least we investigated the ir-anf release, as the endocrinal function of the right heart, in this model. following the endotoxin administration we observed a massive increase of the pulmonary ... | 1991 | 1833887 |
| left ventricular hypertrophy: dissociation of structural and functional effects by therapy. | the heart is one of the major target organs that becomes secondarily involved with the unrelenting and progressive vascular disease of essential hypertension. as a result of this increasing afterload that is imposed upon the left ventricle, the ventricular chamber adapts structurally and functionally. structural changes involve an increase in muscle mass that is achieved through left ventricular hypertrophy (in a manner similar to the arteriolar changes demonstrated by increased thickening). unl ... | 1991 | 1839347 |
| stretch-induced increase in the ca2+ sensitivity of myofibrillar atpase activity in skinned fibres from pig ventricles. | the increase in force development in the heart with increase in end-diastolic pressure (frank-starling mechanism) has been ascribed to an increase in contractile responsiveness of the myofibrils to calcium. we now show that this calcium sensitization is also associated with an increase in calcium responsiveness of the myofibrillar atpase. thus, at submaximal ca activation (pca 6.0), the atpase activity of skinned fibres from pig right ventricles is increased from 57.9 +/- 4.4% to 70.6 +/- 4.4% o ... | 1990 | 2139931 |
| responses of slowly and rapidly adapting receptors in the airways of rabbits to changes in the starling forces. | 1. the responses of the rapidly adapting receptors (rars) and the slowly adapting receptors (sars) of the airways to changes in the starling forces regulating fluid exchange in the pulmonary extravascular space were investigated in anaesthetized rabbits. the hydrostatic pressure in the pulmonary microvasculature was raised by partial obstruction of the mitral valve (mean left atrial pressure increased by approximately 5 and 10 mmhg above the control values) and the concentration of plasma protei ... | 1991 | 1886073 |
| cardiac dysfunction in a rat model of chronic bacteremia. | cardiac function was examined in vivo and in vitro in rats to determine if cardiac dysfunction could be demonstrated in a nonlethal model of infection. bacteremic rats (n = 6) had a subcutaneous polymicrobial abscess produced via repeated inoculations of an encapsulated foreign body with escherichia coli, bacteroides fragilis, and staphylococcus aureus while control rats (n = 6) had the same subcutaneous, encapsulated foreign body (an inflammatory focus) but were not inoculated with bacteria. ca ... | 1990 | 2192813 |
| in utero ventilation augments the left ventricular response to isoproterenol and volume loading in fetal sheep. | in its normal circulatory environment, the fetal left ventricle can maximally increase output less than 2-fold, in contrast to the nearly 3-fold increase that occurs at birth. several studies have attributed this finding to fetal myocardial "immaturity," and speculated that there is a rapid maturation of the myocardium in the perinatal period. we investigated the importance of the circulatory environment itself, rather than myocardial immaturity, by measuring left ventricular output (lvo) during ... | 1991 | 1896250 |
| comparative studies of the covalent binding of [14c]-2-chloro-4-acetotoluidide by liver and kidney slices of the starling. | in tissue slices of female starlings, binding of [14c]-2-chloro-4-acetotoluidide (cat) radioactivity to liver proteins was almost five times greater than binding to kidney proteins after 2 h of incubation. binding to protein of liver slices increased in a log linear fashion with increasing cat concentrations. binding to protein of kidney slices also increased with increasing concentrations but not in a log linear fashion. mixed-function oxidase inhibitors, skf 525-a and alpha-naphthoflavone, dec ... | 1991 | 1918797 |
| characterization of covalent binding of [14c]-2-chloro-4-acetotoluidide to microsomes of starling liver and kidney. | in this study, we have characterized the covalent binding of [14c]-2-chloro-4-acetotoluidide (cat) radioactivity to microsomes of starling liver and kidney. the maximal velocity (vmax) of covalent binding and apparent michaelis constant (km) for both tissues were similar. the vmax for liver and kidney were 52.8 and 68.9 pmol/min/mg protein, and the apparent kms were 0.54 and 0.87 mm, respectively. the covalent binding of radioactivity to heat-denatured microsomes of liver and kidney was reduced ... | 1991 | 1941900 |
| responses to changes in filling and contractility of indices of human left ventricular mechanical performance. | 1. beat-by-beat indices of contractility for assessment of inotropic effects in a given subject were studied using pacing with beta-adrenergic blockade, in eight patients undergoing routine left heart catheterization. a catheter-tip manometer was sited in the left ventricle and an electromagnetic velocity transducer was mounted further back on the same catheter so that it was sited in the ascending aorta. 2. the maximum rate of rise of left ventricular pressure (dplv/dtmax), and of aortic veloci ... | 1990 | 1972191 |
| in vitro assessment of cardiac performance after irradiation using an isolated working rat heart preparation. | the effect of irradiation on cardiac function was assessed using an isolated working rat heart preparation. the animals were given single doses of x-rays in the range 15-30 gy to their hearts. cardiac output (co = aortic flow + coronary flow), heart weight and body weight were followed for a period of 10 months after treatment. irradiation led to a decrease in cardiac function. this reduction was dose-dependent and progressive with time after treatment. the shape of the frank-starling curves con ... | 1991 | 1674271 |
| resistance of descending vasa recta to the transport of water. | the effect of varying intracapillary oncotic pressure on the rate of transcapillary volume flux in microperfused descending vasa recta (dvr) was studied during furosemide diuresis in the munich-wistar rat. at the papillary base, plasma protein concentration and hydraulic pressure were 5.7 +/- 0.1 g/dl and 11.7 +/- 0.7 mmhg in nonperfused dvr, respectively, and 5.6 +/- 0.1 g/dl and 9.4 +/- 0.4 mmhg in nonperfused ascending vasa recta (avr), respectively. these results demonstrate that the papilla ... | 1990 | 1699435 |
| an evaluation of pulsus alternans in closed-chest dogs. | pulsus alternans is a condition in which the arterial pressure generated by the heart oscillates between two levels on a beat-to-beat basis. we evaluated the onset of pulsus alternans in chronically instrumented dogs subjected to tachycardia and inferior vena caval occlusion. during pulsus alternans, the left ventricular (lv) end-diastolic volume (edv) was larger before the strong beats (28.7 +/- 5.3 vs. 25.9 +/- 4.5 ml, p less than 0.001 by paired t test), suggesting that the frank-starling mec ... | 1992 | 1733317 |
| a two-dimensional morphometry-based model of interstitial and transcapillary flow in rabbit synovium. | the synovial lining of a joint is a layer of specialized connective tissue, containing fenestrated capillaries, that regulates the volume and composition of fluid in the joint cavity. the hydraulic conductance of the synovial lining and of the plasma-to-cavity pathway is increased by high intra-articular pressures (iap greater than 9 cmh2o) and this is accompanied by an increase in the interstitial pathway's area/pathlength ratio. in order to assess the contribution of the altered pathway geomet ... | 1991 | 1768416 |
| studies of myocardial protection in the immature heart. iv. improved tolerance of immature myocardium to hypoxia and ischemia by intravenous metabolic support. | thirteen immature puppies (2 to 4 kg) underwent 1 hour of acute hypoxia (oxygen tension 25 to 30 mm hg), followed by 45 minutes of normothermic global ischemia on total vented bypass with normal blood reperfusion. ventricular function was assessed by inscribing starling function curves and measuring stroke work indices before hypoxia and after reperfusion. seven puppies (control) received normal saline infusion at 4 ml/kg/hr. six other puppies received a 4 ml/kg/hr intravenous infusion of glutam ... | 1991 | 1986167 |
| activity patterns of primary auditory-nerve fibres in chickens: development of fundamental properties. | we have examined the activity patterns of single auditory-nerve fibers in the chicken and tested for possible changes during post-hatching development. for this purpose, we recorded from fibres in the cochlear ganglion of chickens of two age groups (about p2 and p21) and investigated their spontaneous and sound-evoked activity patterns under nembutal-chloralhydrate anaesthesia. the spontaneous activity of primary auditory neurones was irregular, the average rates were between 20.5 (p2) and 23 (p ... | 1991 | 1774201 |
| studies of myocardial protection in the immature heart. v. safety of prolonged aortic clamping with hypocalcemic glutamate/aspartate blood cardioplegia. | this study tests the hypothesis that multidose, hypocalcemic aspartate/glutamate-enriched blood cardioplegia provides safe and effective protection during prolonged aortic clamping of immature hearts. of 17 puppies (6 to 8 weeks of age, 3 to 5 kg) placed on vented cardiopulmonary bypass, five were subjected to 60 minutes of 37 degrees c global ischemia without cardioplegic protection and seven underwent 120 minutes of aortic clamping with 4 degrees c multidose aspartate/glutamate-enriched blood ... | 1991 | 1986168 |
| starling forces and lymphatic drainage in pleural liquid and protein exchanges. | pleural liquid volume and protein concentration (c) were determined in rabbits 60 min after a 2 ml hydrothorax with various albumin concentrations in ringer, homologous serum or plasma. the absorption rate of the hydrothorax decreased with the increase in colloid osmotic pressure of the pleural liquid (pi), being 0.56 +/- 0.03, 0.32 +/- 0.02 and 0.17 +/- 0.05 ml/h with ringer, 1.1 and 3 g% albumin, respectively, and nil with 5% albumin, serum or plasma. c increased with ringer and 1.1% albumin, ... | 1991 | 1780605 |
| lymph flow transients following elevation of venous pressure in the dog hindpaw. | lymph flow transients were studied in a dog paw preparation when venous pressure was elevated by 15 and 25 mmhg. the lymph flow transients showed a very rapid initial increase which then declined to a steady-state value that was one-half the peak lymph flow response for both pressure changes. lymph flow increased in the initial 5.3 minutes following venous pressure elevation to 10.4 +/- 2.0 and 18.1 +/- 4.5 times the normal lymph flow (mean +/- standard deviation) for the 15 and 25 mmhg increase ... | 1991 | 1791726 |
| role of mixed-function oxidases and non-protein sulfhydryl content in [14c]-2-chloro-4-acetotoluidide binding to liver and kidney in starlings. | the compound 2-chloro-4-acetotoluidide (cat) is highly toxic to many avian species, including the starling. in our earlier work, we demonstrated the covalent binding of radioactivity from [14c]-cat to liver and kidneys of the starling. in the present study, the effects of inducers of mixed-function oxidase (mfo) and non-protein sulfhydryl (npsh) depletor on the total and covalent binding of [14c]-cat radioactivity to liver and kidney of the starling were examined. the total and covalently bound ... | 1990 | 2084182 |
| evaluation of equine digital starling forces and hemodynamics during early laminitis. | a carbohydrate overload model was used in 8 horses to evaluate starling forces and hemodynamics of the digit during the prodromal stage of acute laminitis. a pump-perfused extracorporeal digital preparation was used to evaluate blood flow, arterial pressure, venous pressure, capillary pressure, isogravimetric capillary filtration coefficient, osmotic reflection coefficient, and vascular compliance. from these data, pre- and postcapillary resistances and pre- to postcapillary resistance ratios we ... | 1990 | 2085218 |
| hormones as regulators of pancreatic secretion in man. | at the beginning of the century, pavlov suggested that the pancreas was exclusively controlled by the nervous reflex mechanisms. in 1902, bayliss & starling published their experiments on secretin and claimed that the nervous regulation is 'superfluous and improbable'. in the following decades, especially after the discovery of cck, it was generally held that exocrine pancreatic secretion is regulated mainly by hormones. the present summary clearly demonstrates the importance of the cholinergic ... | 1990 | 2124994 |
| atriopeptin 24 regulates myocardial function via frank-starling mechanism in conscious dogs. | recent studies have shown that the infusion of atriopeptins decreases blood volume because of the diuresis and also because of changes in vascular volume. in dogs chronically instrumented for the measurement of left ventricular pressure and internal left ventricular diameter, infusion of atriopeptin 24 (500 ng.kg-1.min-1 for 1 h), steady-state plasma levels of 6,000 pg/ml resulted in 5.9 +/- 1.7% decrease in left ventricular (lv) end-diastolic diameter (edd) from 34.7 +/- 2.3 mm (p less than 0.0 ... | 1990 | 2137297 |
| early onset of increased transcapillary albumin escape in awake diabetic rats. | alteration in transcapillary albumin escape rate (teralb) is an indicator of changes in macromolecular movement at the capillary filtering bed, which can change the balance of starling forces for fluid movement from the vasculature to the interstitium and has an impact on volume homeostasis. teralb can be affected by morphological changes in the capillary membrane and/or alterations in the starling forces driving larger solutes across the capillary membrane via convection. previous studies have ... | 1990 | 2142657 |
| auditory duration discrimination in the european starling (sturnus vulgaris). | auditory duration discrimination was studied in the european starling (sturnus vulgaris, n = 3) using a go/nogo-procedure. acoustic signals were presented by the method of constant stimuli. duration discrimination limens (ddls) were determined using signal detection theory (threshold criterion d' = 1.8). weber fractions delta t/t = 0.23 for reference durations of between 800 and 100 ms, respectively. the ddls for reference durations of 400 and 200 ms did not differ from those of 800 ms. there wa ... | 1990 | 2212285 |
| solute-coupled liquid absorption from the pleural space. | the occurrence of a solute-coupled absorption of liquid from the pleural space was studied by measuring in anesthetized rabbits the volume of liquid of the right pleural space 1 h after injecting into it 2 ml of ringer solution or of ringer with an inhibitor of a na(+)-cl- coupled transport or of the na+/k+ pump. volume collected after ringer was 1.56 +/- 0.08 ml. initial volume being 2.2 ml, net absorption rate was 0.64 ml/h. volume collected after disulfonic stilbene (0.1 mm) or bumetanide (0. ... | 1990 | 2218104 |
| differences in the recovery of right and left ventricular function after ischaemic arrest and cardioplegia. | differential susceptibility of right (rv) and left (lv) ventricles to plain ischaemia and the contribution of cardioplegia in reducing the ischaemic damage was evaluated in a sheep model of cardiopulmonary bypass. sheep (n = 16) were equally divided for the two protocols of the study. each sheep served as its own control. rv and lv functions were studied and compared by plotting ventricular function curves (starling and sarnoff). the mathematical centre of mass (com) for each curve was computed ... | 1990 | 2223120 |
| regional blood flow to canine parietal pleura and internal intercostal muscle. | transcapillary starling forces in the parietal pleura and the underlying interstitium may potentially contribute to the exchange of fluid across this barrier. however, the extent of blood flow to the parietal pleura has not been measured. thus, using standard microsphere techniques, we compared blood flow to the parietal pleura, including the subpleural interstitium, with blood flow to the adjacent internal intercostal muscle, as well as with flows to other serous tissues, including mediastinal ... | 1991 | 2010416 |
| transperitoneal fluid dynamics in rabbit liver. | the peritoneal cavity of 18 anesthetized spontaneously breathing supine rabbits was opened through a midline section. one or two hollow capsules (surface area 0.8 cm2) were glued to the exposed liver surface, filled with whole or 25% diluted plasma, and connected to a transducer and a graduated pipette. various hydraulic pressures (pcap) were set in the capsule; at each pcap the liquid flow per unit surface area (v/s) between the disse's interstitial space and the capsule was measured from the r ... | 1990 | 2228874 |
| cardiac myosin heavy chain mrna expression and myocardial function in the mouse heart. | the vertebrate heart contains two myosin heavy chain isoforms, alpha and beta, which are differentially expressed. to establish a murine model for gene-targeting experiments, we defined the precise temporal expression of the myosin isoforms during cardiogenesis and obtained quantitative measurements of cardiac performance. the relative levels of the alpha- and beta-cardiac transcripts were determined by isolating the rna from the hearts of cd-1 mice during development and hybridizing the prepara ... | 1991 | 2036722 |
| indirect estimation of filtration variables in rat lungs calculated by protein concentration or osmotic pressure method. | we reported a new way for estimating filtration variables: k(filtration coefficient), ppmv (perimicrovascular pressure) and sigma (protein reflection coefficient), from 3 different measurements of weight gain at two protein concentrations of perfusate (cmv) and at two vascular pressures (pvasc). we used the starling equation for calculating those variables using two different formulas which expressed that all protein moves by convection. in this report, we compared those two formulas: 1) 1--sigm ... | 1991 | 2048125 |
| mechanism of sustained mechanical alternans. effect of variations in ventricular billing volume. | this study investigations the phenomenon of sustained mechanical alternans (sma) through the use of quantitative criteria. discrete analysis is used to demonstrate that the hemodynamic variables during sma are governed by a simple mathematical relation. the analysis shows that the value of the slope created by the two alternating beats on the stroke volume (sv)-end-diastolic volume (edv) plane is gamma = (mu - 1) (1 + beta)/(mu - beta), where mu = svs/svw, and svs and svw denote the strong and w ... | 1991 | 2054940 |
| alterations in myocardial contractility in conscious dogs with dilated cardiomyopathy. | we investigated the changes in left ventricular (lv) geometry and myocardial contractility in eight conscious chronically instrumented dogs studied before and after the development of dilated cardiomyopathy induced by rapid ventricular pacing. significant increases (p less than 0.01) were observed in cardiac dimensions in both the lv long and short axes and in end-diastolic volume (control: 53 +/- 1 ml; cardiomyopathy: 76 +/- 2 ml) and end-systolic volume (control: 27 +/- 2 ml; cardiomyopathy: 5 ... | 1991 | 2058725 |
| local and global function of the right ventricle in a canine model of pulmonary microembolism and oleic acid edema: influence of ventilation with peep. | right ventricular (rv) dysfunction may occur due to increased rv afterload and, hence, might also contribute to the decrease in cardiac output following institution of peep in patients with adult respiratory distress syndrome (ards). to test this hypothesis, the authors examined the influence of peep on local and global rv function in 12 anesthetized dogs with experimental ards (eards) induced by pulmonary microembolization with glass beads and oleic acid. local rv function was analyzed in the r ... | 1990 | 2240686 |
| effects of abdominal pressure on venous return: abdominal vascular zone conditions. | the effects of changes in abdominal pressure (pab) on inferior vena cava (ivc) venous return were analyzed using a model of the ivc circulation based on a concept of abdominal vascular zone conditions analogous to pulmonary vascular zone conditions. we hypothesized that an increase in pab would increase ivc venous return when the ivc pressure at the level of the diaphragm (pivc) exceeds the sum of pab and the critical closing transmural pressure (pc), i.e., zone 3 conditions, but reduce ivc veno ... | 1990 | 2076989 |
| progressive coronary vasoconstriction during 25 hours of myocardial preservation in vitro impairs functional capacity following preservation. | we have developed perfusion techniques for preserving rat hearts for 25 h and have quantified haemodynamic function after preservation to establish the relation between coronary vascular resistance during preservation and the quality of postpreservation pump function. thirteen rat hearts underwent hypothermic (8 degrees c), low-pressure (15 mmhg) perfusion with an hyperosmotic (385 mosm/l) crystalloid preservation buffer for 25 h. during this period, the coronary flow rate decreased from 1.12 +/ ... | 1989 | 2635942 |
| effect of endotoxin administration on equine digital hemodynamics and starling forces. | using a pump-perfused extracorporeal isolated digital preparation, the effects of a 30-minute infusion of either saline solution (control) or endotoxin on equine digital hemodynamics and microvascular function were determined. digital blood flow and arterial, venous, and capillary pressures were recorded at 15-minute intervals for 150 minutes. from these data, total vascular resistance and pre- and postcapillary resistances were calculated. isogravimetric capillary filtration coefficient, vascul ... | 1990 | 2240793 |
| studies of myocardial protection in the immature heart. i. enhanced tolerance of immature versus adult myocardium to global ischemia with reference to metabolic differences. | this study compares the metabolism and functional responses of adult and immature hearts to a standard ischemic insult. ten adult dogs (25 to 27 kg) and 10 puppies (6 to 10 weeks old) underwent 45 minutes of aortic clamping on bypass. preoperative and postoperative ventricular performance (starling curves), biochemical factors, and water content were measured. global ischemia in adults produced a 30% mortality rate (3/10) and low output syndrome in survivors (33% recovery of stroke work index). ... | 1990 | 2246910 |
| [central and peripheral circulation in patients after orthotopic transplantation of the heart]. | heart transplantation in human medicine is a unique model which makes it possible to study circulatory changes in complete denervation of the heart. the authors examined repeatedly the central and peripheral haemodynamics after orthotopic heart transplantation (ots) in 11 patients (11 males, 1 female; mean age 44 +/- 4 years) following an interval of three months to four years after the operation. the values of central haemodynamics at rest varied in the majority within the normal range. after a ... | 1989 | 2662579 |
| right-left ventricular balance in implanted electrically powered artificial hearts. | an electrohydraulic total artificial heart (ehtah), using an interatrial shunt (ias) for right-left heart balance, was evaluated in acute, in vivo, open-chested calves. the ehtah system demonstrated physiologic autoregulation with starling-like responsiveness to preload. output varied from 4 to 9 l/min, as right atrial pressure increased from 3 to 15 mmhg. device output was minimally influenced by afterload. the efficacy of an ias to balance the ehtah was demonstrated over a wide range of preloa ... | 1990 | 2252680 |
| variation and correlation in human fetal umbilical doppler velocities with fetal breathing: evidence of the cardiac-placental connection. | doppler velocity waveforms in the human fetal umbilical vein and artery were analyzed during episodes of fetal breathing. heart rate, systolic and diastolic velocities were measured from the umbilical artery waveform. diastolic velocity varied the most with a mean (+/- sd) coefficient of variation of 16.0% +/- 5.0%. the coefficient of variation of systolic velocity was 7.8% +/- 2.4% and of heart rate was 5.0% +/- 1.8%. we also found that umbilical arterial flow was related to umbilical venous fl ... | 1990 | 2256484 |
| forces involved in transcapillary fluid movement in exercising cat skeletal muscle. | average capillary pressure (pc) close to the venous end (fluid equilibrium point) of the exchange vessels (denoted pc,v), arterial (pa) and venous pressure, and the rate of net transcapillary fluid flux were continuously recorded in sympathectomized muscle during 30 min of graded exercise and for 30 min in the post-exercise period. regional changes in colloid osmotic pressure (pi pl) and total osmolality in plasma, the latter reflecting work-induced interstitial hyperosmolality, were measured at ... | 1990 | 2267951 |
| the effects of increasing mean arterial pressure on left ventricular output in newborn lambs. | we developed a preparation in which the mean arterial pressure of the newborn lamb is varied with little change in left ventricular preload. seven lambs underwent balloon atrial septostomy and were instrumented with vascular catheters, an electromagnetic flow transducer on the aorta, and a balloon occluder on the aorta. four different preload conditions were established by volume infusion or withdrawal. aortic flow was measured continuously during gradual occlusion of the aorta. curves relating ... | 1990 | 2364497 |
| inhibition of hypoxic pulmonary vasoconstriction by increased left atrial pressure in dogs. | to further explore the mechanism of hypoxic pulmonary vasoconstriction, we studied the mean pulmonary arterial pressure (ppa)/left atrial pressure (pla) relationship at fixed cardiac index (q) and the ppa/q relationship at several levels of fixed pla in pentobarbital sodium-anesthetized dogs ventilated alternately in hyperoxia [fraction of inspired o2 (fio2) 0.4 or 1.0] and in hypoxia (fio2 0.1). in all experimental conditions, ppa/q plots were linear with extrapolated pressure intercepts (pi) n ... | 1990 | 2375417 |
| brain cholinesterase activity of nestling great egrets, snowy egrets and black-crowned night-herons. | inhibition of brain cholinesterase (che) activity in birds is often used to diagnose exposure or death from organophosphorus or carbamate pesticides. brain che activity in the young of altricial species increases with age; however, this relationship has only been demonstrated in the european starling (sturnus vulgaris). brain che activity of nestling great egrets (casmerodius albus) collected from a colony in texas (usa) increased significantly with age and did not differ among individuals from ... | 1989 | 2761008 |
| effects of acutely impaired regional function on remote myocardial wall motion and blood flow in the canine left ventricle studied by coronary occlusion and hypoxic perfusion. | the aim was to examine whether regional myocardial dysfunction has a significant effect on the wall motion and blood flow in remote non-ischaemic regions. | 1990 | 2386988 |
| integrative nature and time course of cardiovascular alterations in the diabetic rat. | time-dependent alterations in integrated cardiovascular function were assessed in the streptozotocin-diabetic rat. hemodynamic measurements in the intact, anesthetized animal revealed significant and progressive reduction in heart rate after 2, 4, and 8 weeks of diabetes. myocardial contractility (+ dp/dt) and rate of relaxation (-dp/dt) were preserved at 2 weeks, but progressively declined thereafter. integrative mechanisms maintained mean arterial blood pressure within normal limits at all tim ... | 1986 | 2422482 |
| the effects of intravenous infusion of solutions with different colloid osmotic pressures on rat mesenteric lymph pressure. | the effects of intravenous infusion of solutions of varied colloid osmotic pressure on mesenteric lymph pressure were measured by a glass micropipette. the lymph pressure was 4.0 +/- 1.6 cm h2o between the second and third valve of rat mesenteric lymphatic vessels with diameter of 101 +/- 25 micron (mean +/- sd). intravenous infusion of 1 ml/100g body weight (b.w.) of isotonic saline, 5% glucose solution, and 20% glucose solution increased the lymph pressure by 1.6 +/- 0.5 cm h2o, 1.5 +/- 0.3 cm ... | 1986 | 2431233 |
| immunohistochemical localization of neuropeptides in the vocal control regions of two songbird species. | immunohistochemistry was used to map the distribution of four neuropeptides in song control regions of two songbird species, the european starling (sturnus vulgaris) and the song sparrow (melospiza melodia). we searched for positively stained cell bodies or apparent terminals containing vasoactive intestinal peptide (vip), methionine-enkephalin (met), cholecystokinin (cck), and substance p (sub p). intraventricular colchicine pretreatment was administered to enhance the visualization of peptide- ... | 1988 | 2452178 |
| the regulation of the ratio of the cardiopulmonary blood volume to stroke volume in sheep. | volume expansion with dextran was used in unanaesthetised sheep to investigate the mechanisms which are responsible for keeping the ratio of the cardiopulmonary blood volume to stroke volume (cpfi) constant under physiological conditions. for animals with heart rates lower than 80, active pulmonary vasoconstriction was mainly responsible for the regulation obtained with volume expansion, while the starling mechanism was responsible for keeping the ratio constant for animals with heart rates abov ... | 1989 | 2482132 |
| 2(1h)-quinolinones with cardiac stimulant activity. 2. synthesis and biological activities of 6-(n-linked, five-membered heteroaryl) derivatives. | a series of 6-(n-linked, five-membered heteroaryl)-2(1h)-quinolinone derivatives was synthesized and evaluated for cardiotonic activity. most compounds were prepared by sulfuric acid catalyzed cyclization of an n-(4-heteroarylphenyl)-3-ethoxypropenamide or by condensation of a 2-amino-5-heteroarylbenzaldehyde or -acetophenone derivative with the ylide derived from triethyl phosphonoacetate. in anesthetized dogs, 6-imidazol-1-yl-8-methyl-2(1h)-quinolinone (3; 25 micrograms/kg) produced a greater ... | 1989 | 2537423 |
| 2(1h)-quinolinones with cardiac stimulant activity. 3. synthesis and biological properties of 6-imidazol-1-yl derivatives. | a series of 6-imidazol-1-yl-8-methyl-2(1h)-quinolinones was synthesized and evaluated for cardiac stimulant activity in dogs. the majority of compounds were prepared from an appropriate 6-imidazol-1-yl-2(1h)-quinolinone precursor or by sulfuric acid catalyzed cyclization of an n-(4-heteroarylphenyl)-3-ethoxypropenamide. introduction of a range of 5-substituents into 6-(2,4-dimethylimidazol-1-yl)-8-methyl-2(1h)-quinolinone (1) reduced inotropic activity in anesthetized dogs (percentage increase i ... | 1989 | 2544726 |
| effect of increased alpha-adrenergic activity on the blood pressure/cardiac output relationship in dogs. | the relationship between mean aortic blood pressure (map) and cardiac output (co) was examined in anaesthesized, open-chest dogs during variations in pre-load with and without alpha-adrenergic stimulation with phenylephrine. when phenylephrine increased map to 200 mmhg, co fell greatly and could not be increased by volume expansion. left ventricular ultrasonic measurements and pressure recordings showed that the frank-starling mechanism was maximally activated. during vena cava obstruction co an ... | 1989 | 2564244 |
| [comparative research on erythrocyte anionic adenosine triphosphatase in vertebrates]. | studies have been made on the level of activity of anion atpase and its sensitivity to anions in erythrocytic membranes from fishes, amphibians, reptiles, birds and mammals. significant variations in these properties of the atpase were found among the species investigated. protein composition of erythrocytic membranes was also investigated by means of disc-electrophoresis in polyacrylamide gel in men, rabbit, rat, mouse, hamster, tortoise, crow and starling. | 1985 | 2986389 |
| is a decrease in plasma oncotic pressure enough to explain the edema of pregnancy? | the balance of fluid across capillaries is given by the starling equation. because the plasma protein concentration (one of its components) is decreased in pregnancy, we decided to explore the question as to whether hypoproteinemia with intact protein mass (produced by blood volume expansion) or hypoproteinemia with decreased total protein mass (produced by removal of circulating proteins) alters the oncotic pressure differences across capillaries. we calculated the oncotic pressure difference o ... | 1989 | 2603920 |
| cellular mechanism of the modulation of contractile function by coronary perfusion pressure in ferret hearts. | 1. isovolumic left ventricular pressure was measured at various coronary arterial pressures in langendorff-perfused ferret hearts. the concentrations of phosphorus-containing metabolites were measured using 31p nuclear magnetic resonance (nmr). intracellular free calcium concentration ([ca2+]i), was measured with 19f nmr in a group of hearts that were loaded with the calcium indicator 5f-bapta. 2. developed pressure increased when coronary arterial pressure was raised from the control value of 8 ... | 1989 | 2607438 |
| [estimation of the filtration variables in the rat lung]. | the filtration variables, filtration coefficient (k), perimicrovascular pressure (ppmv) and reflection coefficient (sigma) were estimated independently in previous reports using the starling equation or the micropuncture method. we estimated these variables simultaneously. we measured filtration rate by a gravimetric method in isolated rat lung lobes in zone 1 conditions (alveolar pressure = 20 cmh2o) at two vascular pressures, pvasc = 15 or 8 cmh2o and perfused the lobes with plasma containing ... | 1989 | 2615069 |
| non-immune fab- and fc- mediated interactions of avian ig with s. aureus and group c and g streptococci. | serum samples from 19 avian species representing 8 orders were tested for their capacity to inhibit the fab- and fc-mediated immunoglobulin binding to protein a-carrying s. aureus and protein g-carrying group c and g streptococci. four species (mallard, dunlin, starling and blackbird) belonging to three different orders showed a high degree of fc-mediated protein a- and protein g-reactivity. five species demonstrated a high level and nine species exhibited a low level of fab-mediated protein a-r ... | 1988 | 3126785 |
| effects of small changes in carotid sinus pressure on renal haemodynamics and function in dogs. | 1. in dogs anaesthetized with chloralose and artificially ventilated, the carotid sinuses were vascularly isolated and perfused with arterial blood. mean aortic pressure was held constant at 111 +/- 2 mmhg (mean +/- s.e.m., n = 18) by means of a pressure bottle connected to the aorta and a starling resistance. both vagus nerves were sectioned in the neck and propranolol hydrochloride (1 mg kg-1 h-1) or atenolol (0.5-4 mg kg-1 h-1) was administered. the left and right renal blood flows were measu ... | 1989 | 2621595 |
| [recent physiologic and pathophysiologic studies in heart function in the perinatal period]. | recent investigations of the cardiac output in fetal lambs have shown that left ventricular output reaches nearly exclusively the upper circulation of the body (head, neck, forelegs) via the ascending aorta. right ventricular output supplies predominantly the descending aorta via the ductus arteriosus. increasing afterload results in reductions of stroke volumes in the fetus as well as in the neonate. the frank-starling-mechanism is only weakly developed in lambs before and after birth. immediat ... | 1988 | 3188706 |
| differentiation of various cardiovascular drugs by means of specific myocardial and vascular load tests. experiments at the isolated perfused heart. | a new method is described for examining the contractile function of myocardium and coronary vasculature in the isolated perfused, electrically stimulated guinea-pig and rat heart which is suitable for investigation of cardiovascular drugs. the criterion used for functional efficiency of myocardium and coronary vasculature is--in addition to the usual evaluation of cardiac force and coronary flow in steady-state--the reaction of the heart to perfusion pressure changes: abrupt increase of the perf ... | 1989 | 2624601 |
| myocardial dysfunction in sepsis. | the characteristic hemodynamic profile of human septic shock consists of a normal or elevated cardiac index and a decreased systemic vascular resistance index. when a patient with septic shock has a low cardiac index, concomitant hypovolemia is usually present. within 48 hours of the onset of septic shock, most patients develop marked dilatation of both ventricles, depressed ejection fractions, and alterations of the frank-starling and diastolic pressure-volume relationships; stroke volume typic ... | 1989 | 2647229 |
| model for the physics and physiology of fluid administration. | this article describes a model designed to provide an understanding of fluid flow in intravenous systems and human subjects. experiments were developed which demonstrate that the model can represent common clinical situations. the model depicts physical devices as ideal resistors, pressure sources, and flow sources. the patient's venous system is depicted as a combination of ordinary and starling resistors. for flows between 0 and 300 ml/hr, both physical devices and patients are adequately repr ... | 1989 | 2656923 |
| interplay among cardiac chambers. left and right ventricular performance during changes in contractility, afterload and during simultaneous atrio-ventricular contraction. | 1. only a slight increase in stroke volume is observed during a selective left-sided inotropic stimulation of the in situ pig heart. decreased left ventricular preload during left-sided inotropic stimulation reduces activation of the frank-starling mechanism and hence explains the rather small increase in stroke volume. we suggest that left-sided inotropic stimulation redistributes blood from the pulmonary circulation toward the systemic circulation causing a fall in pulmonary artery pressure an ... | 1989 | 2668474 |
| relation between capillary pressure and vascular tone over the range from maximum dilatation to maximum constriction in cat skeletal muscle. | an attempt was made to assess, from a large sample (n = 567), the normal level of hydrostatic capillary pressure (pc) in resting skeletal muscle and the extent of pc regulation as effected by strictly graded activation of metabolic and adrenergic control mechanisms over the entire physiological range of vascular tone. with the use of a new whole-organ technique, pc towards the venous end of the capillary was continuously recorded at constant arterial pressure (100 mmhg) and under simultaneous ob ... | 1990 | 2275407 |
| iodide and albumin kinetics in normal canine wrists and knees. | the clearance rates of free iodide and of radioiodinated serum albumin were measured in the knee and wrist joints of 9 normal adult dogs. iodide clearance from the knee was 3 times greater than that from the wrist. in contrast, radioiodinated serum albumin clearance from the knee was only slightly greater than that from the wrist. interpreted as respective indices of effective synovial plasma flow and lymphatic drainage, these values indicate that the filtration fraction is normally greater in m ... | 1990 | 2302270 |
| a new method for estimating filtration variables in isolated zone 1 rat lung. | the filtration variables, k (filtration coefficient), ppmv (perimicrovascular pressure) and sigma (reflection coefficient), were estimated independently in previous reports using the starling equation or the micropuncture method. we used matrix algebra to estimate these variables simultaneously. we measured filtration rate (q) by a gravimetric method in isolated rat lung lobes in zone 1 conditions (alveolar pressure = 20 cmh2o) at two vascular pressures, pvasc = 15 or 18 cm h2o and perfused the ... | 1990 | 2353356 |
| [clinical and experimental studies on the pathogenesis in pregnancy induced hypertension]. | placental ischemia is one of the etiological factors of pregnancy induced hypertension (pih), however, the pathogenesis of placental and renal ischemia has not been clarified. the purposes of this investigation are (1) to clarify the fetomaternal hemodynamic changes in pih and the influence of maternal postural change on fetomaternal hemodynamics, measured by thermodilution method, impedance cardiography and pulsed doppler method during pregnancy, (2) to provide to relationship between intrauter ... | 1988 | 3251961 |
| starling resistor versus compliance. which explains the zero-flow pressure of a dynamic arterial pressure-flow relation? | arterial pressure at zero flow (pz = 0) that is higher than venous pressure (pv) in dynamic pressure-flow relations has been explained by the presence of an arteriolar starling resistor (sr) mechanism (i.e., vascular waterfall) or the discharge of vascular capacitance. to determine which was predominant, i studied in vivo hind limbs of 18 anesthetized dogs in which femoral arteries were cannulated with in-line electromagnetic flow probes to measure inflow (qin), pv was controlled, and collateral ... | 1990 | 2364491 |
| the hemoglobins of the adult blackbird (turdus merula, passeriformes). the sequence of the major (hba) and minor component (hbd). | the blood of the adult blackbird contains one major hemoglobin component (hba = alpha a2, beta 2, ca. 80%) and one minor one (hbd = alpha d2 beta 2, ca. 20%). the hb-components were separated by fplc on a tsk sp-5 pw column, and eluted with a linear nacl gradient, while the globin chains were purified on a cation exchange (cm-cellulose). tryptic peptides from the globin chains were separated by hplc on an rp-2 lichrosorb column. the complete amino acid sequence was determined by automatic edman ... | 1989 | 2757791 |
| blood-nerve transfer of albumin and its implications for the endoneurial microenvironment. | blood-nerve transfer of plasma albumin was studied by measuring the permeability coefficient-surface area (ps) product of the blood-nerve barrier (bnb) to 125i-albumin in rat sciatic nerve using the i.v. bolus injection method. the calculated ps was 6.3 +/- 0.5 (s.e.m.) x 10(-7) ml.g-1.s-1. this value is smaller by more than an order of magnitude of that measured for sucrose and confirms the relative impermeance of the bnb to blood-borne solutes. from a review of the available evidence, it is co ... | 1989 | 2765909 |
| 7-heteroaryl-1,2,3,5-tetrahydroimidazo[2,1-b]quinazolin -2(1h)-one derivatives with cardiac stimulant activity. | a series of 7-heteroaryl-1,2,3,5-tetrahydroimidazo[2,1-b]quinazolin++ +-2 (1h)-ones was synthesized and evaluated in dogs for cardiac stimulant activity. compounds were obtained by a palladium-catalyzed cross-coupling reaction between a heteroarylzinc chloride and a 7-iodo-1,2,3,5-tetrahydroimidazo [2,1-b]quinazolin-2(1h)-one or by cyclization of an n-[(2-aminophenyl)methyl]glycinate with cyanogen bromide. compared to the parent ring system (3), introduction of a 2,6-dimethylpyridin-3-yl (6), 2, ... | 1989 | 2769678 |
| angiotensin ii infusion during beta-adrenergic stimulation by isoproterenol. effects on hepatic, splenic and cardiac blood volumes and on the magnitude and distribution of cardiac output in the dog. | the cardiac and peripheral vascular adjustments to angiotensin ii (0.1-0.2 microgram kg-1 min-1 i.v.) during high beta-adrenergic activity by a continuous isoproterenol infusion (0.2-0.3 microgram kg-1 min-1 i.v.) were examined in anaesthetized, atropinized dogs. hepatic, splenic and left ventricular (lv) volume changes were estimated by an ultrasonic technique, and the blood flow distribution was measured by injecting radioactive microspheres and by electromagnetic flowmetry on the caval veins, ... | 1986 | 2875601 |
| supratentorial pressures. part ii: intracerebral pulse waves. | intracerebral pulse waves were recorded in cat and monkey while intracranial pressure (icp) manipulations were performed. the intracerebral pulse waves appeared comparable to cerebrospinal fluid (csf) pulsations. the wave forms were divided into multiple smaller waves, designated p1 to p4. the p1 component was primarily of arterial origin and was accentuated by increasing icp unrelated to increased venous pressure, most commonly from a mass lesion. bilateral carotid occlusion resulted in decreas ... | 1987 | 2891069 |
| adaptations of the left ventricle to chronic volume overload induced by mitral regurgitation in conscious dogs. | to assess the time-course of adaptive responses of the left ventricle to chronic volume overload, dogs were instrumented with a left ventricular (lv) micromanometer and pairs of ultrasonic crystals for the measurement of lv wall thickness (wth), lv chamber diameter (d), and longitudinal segment length (l). following a control study, mitral regurgitation (mr) was created by a transventricular section of the chordae tendineae. heart rate was controlled during each study by atrial pacing. plasma no ... | 1985 | 2936715 |
| modulation of the natriuretic response to atrial natriuretic peptide by alterations in peritubular starling forces in the rat. | the mechanisms underlying the natriuretic response to infusions of atrial natriuretic peptide (anp) remain incompletely defined. by acting as renal vasodilators, atrial peptides may serve to alter peritubular capillary physical forces and favor a decrease in tubule solute reabsorption. therefore, we studied the effects of known modifiers of intrarenal starling forces on the natriuresis induced by infusion of intravenous hanp [4-28] (0.5 microgram/kg/min) in anesthetized, euvolemic munich-wistar ... | 1986 | 2949885 |
| intestinal capillary filtration in experimental diabetes mellitus. | there is indirect evidence that indicates that intestinal transcapillary fluid and solute exchange is significantly altered in diabetes mellitus. to directly assess the dynamics of microvascular fluid and solute exchange in the small intestine (jejunum-ileum), we measured lymph flow, capillary pressure, capillary filtration coefficient, plasma and lymph oncotic pressures, and the osmotic reflection coefficient in anesthetized, fasted control rats and in rats in which diabetes was induced by a si ... | 1987 | 2955703 |
| chronic exercise and left ventricular structure and function in healthy human subjects. | twelve healthy well-trained participants in a supervised exercise program (mean age, 41.3 yr) were compared with 12 sedentary control subjects (mean age, 38.9 yr) with physical characteristics similar to the exercised group (eg) before training. resting echocardiograms revealed significantly lower heart rates (hr) in the eg compared with control group (cg) but no evidence for cardiac structural differences between groups. radionuclide angiograms performed at rest and during two levels of supine ... | 1985 | 2984158 |
| continuous arteriovenous hemofiltration: an in vitro simulation and mathematical model. | in vitro and mathematical models of continuous arteriovenous hemofiltration (cavh) have been developed. human erythrocytes resuspended in normal saline containing 5% bovine albumin were used to perfuse the circuit from a gravity driven pressure source. membrane hydraulic permeability was observed to decline from 31.2 x 10(-5) +/- 11.9 x 10(-5) cm/(min.mm hg) before use to 12.3 x 10(-5) +/- 3.3 x 10(-5) (mean +/- sd) after use. this fall occurred during the first one to two hours whether perfused ... | 1988 | 3367559 |
| fetal cardiac arrhythmias and their effect on volume blood flow in descending aorta of human fetus. | using a two-dimensional linear array real-time and pulsed doppler ultrasound system, volume blood flow measurements were made in 86 normal pregnancies, seven cases of fetal bradycardia, and seven cases of fetal tachycardia at the lower thoracic level of the fetal descending aorta. during fetal cardiac arrhythmias, volume blood flow was maintained within the normal range until the heart rates reached around 50 bpm and 230 bpm, after which the volume blood flow diminished. the changes observed sug ... | 1986 | 3095391 |
| pulmonary vascular pressure-flow relationship in canine oleic acid pulmonary edema. | we tested the hypothesis that the increased impedance to flow in canine oleic acid (oa) lung injury is predominantly due to an increase in effective downstream pressure (edp), obtained by extrapolating to zero flow the linear portion of the pulmonary artery pressure (pap)/flow (q) relationship. pap-q coordinates were obtained in eight anesthetized, o2-ventilated dogs by varying q through systemic arteriovenous fistulae. pap-q lines were obtained before and approximately 5 h after injection of oa ... | 1986 | 3098112 |
| cardiovascular adjustments to pulmonary vascular injury in dogs. | the hemodynamic effects of blood volume augmentation and mechanical ventilation (mv) with positive end-expiratory pressure (peep) were studied in nine beagles anesthetized with halothane before and after thrombin-induced pulmonary hypertension. the effect of therapy with dopamine, norepinephrine with and without nitroglycerin (ntg), and intraaortic balloon pumping (iabp) were studied in a second series of six beagles. before thrombin, dextran (35 ml.kg-1) caused a significant increase in right a ... | 1988 | 3125766 |
| effect of tracheal smooth muscle tone on collapsibility of immature airways. | to test the influence of smooth muscle tone on extremely immature airways, tracheal segments (n = 19) were excised from premature lambs at 114-121 days gestation and mounted in a chamber filled with krebs solution. inflation (si) and collapsing (sc) compliance were determined by altering transmural pressure from 30 to 0 torr and -30 to 0 torr, respectively, both during control (c) and after acetylcholine (ach) administration (experimental, e). flow (v = 2-15 l/min) was then introduced through th ... | 1988 | 3170433 |
| influence of smooth muscle tone and longitudinal tension on the collapsibility of immature airways. | mechanical properties and pressure-flow relationships of tracheae excised from very premature lambs were studied in a plethysmograph. control (group i) data revealed the tracheae to be extremely compliant, collapsible airways, with an inflation compliance (si) of 0.033 (+/- 0.004 se) mmhg-1, collapsing compliance (sc) of 0.026 (+/- 0.001 se) mmhg-1, and pressure-flow relationships similar to those of a starling resistor. acetylcholine administration (group ii) lowered both si, 0.026 (+/- 0.003 s ... | 1988 | 3194153 |
| the effect of ionic contrast medium on the movement of acutely ischemic and nonischemic canine myocardium. | regional function assessed by ventriculography may be influenced by the hemodynamic effects of rapidly injecting ionic contrast medium. the importance of this after acute coronary occlusion was examined in eight open-chest, anesthetized dogs. the left anterior descending artery was ligated while sonomicrometric segment lengths in the ischemic (iz) and nonischemic zones (nz) were measured. sodium methylglucamine diatrizoate (renografin-76, 1 ml/kg) was rapidly injected over 3 seconds. fifteen min ... | 1988 | 3195438 |
| myocardial depression in hyperdynamic endotoxemia. | the presence of myocardial depression is difficult to assess in most animal models of septic shock caused by hypovolemia. we studied endotoxemia in fluid-resuscitated conscious sheep. they underwent chronic instrumentation with pulmonary artery, arterial, and left atrial catheters. after 1 week of recovery, 1.5 micrograms/kg of endotoxin (lps) was administered intravenously over a period of 30 min. one group of nine sheep stayed on baseline fluids (2 ml/kg/h of ringer's lactate), while a second ... | 1988 | 3197261 |
| bound calcium and force development in skinned cardiac muscle bundles: effect of sarcomere length. | there is evidence that the steep ascending limb of the force-length curve in cardiac muscle (frank-starling relation) is based on a length-dependence of myofilament ca2+ sensitivity. previous work from this laboratory has indicated that in the sarcomere length range corresponding to the ascending limb of the cardiac force length curve (1.7 to 2.3 microns) the ca2+-troponin c affinity is length-dependent. in this study ca2+ binding to chemically skinned bovine cardiac muscle bundles was measured ... | 1988 | 3221407 |
| dynamics of the interventricular septum and ventricular free walls during regional ischaemia in open-chest dogs. | the significance of ischaemia of the left ventricular (lv) and right ventricular (rv) free walls for the dynamics of the interventricular septum (ivs) and the right ventricle was examined in open-chest dogs. left ventricular and rv ischaemia reduced stroke volume similarly, by 11.2 +/- 1.4% and 11.2 +/- 2.4%, respectively. the dynamics of myocardial segment lengths (sl), recorded in the lv and rv free walls and the ivs, differed. during lv ischaemia, end-diastolic sl (edsl) and systolic shorteni ... | 1988 | 3227889 |
| cardiopulmonary dysfunction in a feline septic shock model: possible role of leukotrienes. | the aim of the present study was to explore the possible involvement of leukotrienes (lts) in the development of cardiopulmonary dysfunction in experimental septic shock. sepsis was induced in anesthetized cats by infusion of liver escherichia coli bacteria. one series (n = 6) was pretreated with diethylcarbamazine (dec), a 5-lipooxygenase inhibitor; another series (n = 7) was pretreated with fpl 55712, a ltc4-d4 antagonist; and a third series (n = 8) served as septic controls. after 2 hr of bac ... | 1989 | 2676231 |
| clinical and physiologic significance of local tissue renin-angiotensin systems. | increasing and compelling evidence continues to amass that favors the existence of local tissue renin-angiotensin systems. all renin-angiotensin system components have been demonstrated in kidney, brain, arteries, adrenals, and other organs. favoring its clinical importance are direct demonstration of its components in tissues; dissociation between hemodynamic and structural effects of renin-angiotensin system inhibition; evidence for local modulating roles with other humoral, autocrine/paracrin ... | 1989 | 2690610 |
| reperfusion with atp-mgcl2 following prolonged ischemia improves myocardial performance. | this study was designed to test the hypothesis that infusion of atp-mgcl2 during reperfusion following a prolonged period of hypothermic global ischemia would result in enhanced functional recovery of cardiac function. two groups of dogs (n = 6 each) were placed on cardiopulmonary bypass (cp) with systemic hypothermia to 28 degrees c and subjected to 150 min of aortic cross-clamping. crystalloid cardioplegia was infused every 20 min during ischemia. reperfusion and rewarming were carried out for ... | 1987 | 3498093 |
| acute oral toxicity of sodium cyanide in birds. | sensitivities of six avian species, black vulture (coragyps atratus), american kestrel (falco sparverius), japanese quail (coturnix japonica), domestic chicken (gallus domesticus), eastern screech-owl (otus asio), and european starling (sturnus vulgaris), to acute poisoning by sodium cyanide (nacn) were compared by single dose ld50's. three species, domestic chickens, black vultures, and turkey vultures (cathartes aura), were dosed with nacn to determine cyanide residues in those that died and a ... | 1986 | 3503141 |