| existence of the frank-starling mechanism in the failing human heart. investigations on the organ, tissue, and sarcomere levels. | the frank-starling mechanism is one of the most important physiological principles for regulation of contractile performance. we therefore studied the question of whether this mechanism may be absent or attenuated in end-stage failing human left ventricular myocardium. | 1996 | 8772688 |
| mycoplasma sturni sp. nov., from the conjunctiva of a european starling (sturnus vulgaris). | strain ucmf(t) (t = type strain) was isolated from the conjunctiva of a european starling (sturnus vulgaris) with conjunctivitis. colonies grown on conventional mycoplasma agar possessed the typical fried-egg appearance observed with many mycoplasmal species. electron micrographs of ultrathin sections of ucmf(t) revealed a pleomorphic cellular morphology; the cells ranged from spherical to elliptical or flask shaped. the cell size ranged from 0.3 to 0.5 microns. strain ucmf(t) grows well in a va ... | 1996 | 8782681 |
| a shear stress component to the modulation of capillary hydraulic conductivity (lp). | two major factors that determine transcapillary exchange are starling forces and hydraulic conductivity (lp) of capillary walls. although chemical stimuli alter lp, the influence of mechanical stimuli has been neglected. therefore, we tested the hypothesis that the lp of intact capillaries would increase with the magnitude of changes in shear stress presented to each capillary. | 1996 | 8839445 |
| sarcomere length versus interfilament spacing as determinants of cardiac myofilament ca2+ sensitivity and ca2+ binding. | the ca2+ sensitivity of skinned cardiac muscle can be increased by either an increase in sarcomere length or osmotic compression of the myofilament lattice. the length-dependent change in ca2+ sensitivity is considered to be an important component of the steep force-length relation along the ascending limb of the force-length curve (frank-starling relation). since an increase in sarcomere length is accompanied by a reduction in the spacing between myosin and actin filaments it is not clear wheth ... | 1996 | 8841926 |
| alterations in hemodynamics and left ventricular contractility during carbon dioxide pneumoperitoneum. | carbon dioxide (co2) pneumoperitoneum has been shown to adversely affect hemodynamics in patients. this study specifically examines the potential contribution of altered left ventricular contractility (lvc) to hemodynamic changes observed during co2 pneumoperitoneum. | 1996 | 8864088 |
| starling resistor effects on pulmonary artery occlusion pressure in endotoxin shock provide inaccuracies in left ventricular compliance assessments. | assessment of left ventricular preload and left ventricular compliance changes in septic shock using pulmonary artery occlusion pressure (paop) presumes that this pressure accurately reflects left heart filling pressure. we tested the hypothesis that starling resistor forces render paop inaccurate as an index of left heart filling pressure, resulting in misleading assessments of left ventricular compliance changes. | 1996 | 8874296 |
| simultaneous estimation of filtration variables in isolated rat lungs in zone 3 conditions. | estimation of filtration variables (filtration coefficient, perimicrovascular pressure, and reflection coefficient) is important for evaluating pulmonary microvascular permeability to fluids, especially when the lungs are inflamed, injured, or being preserved for transplantation. here we report a new method for estimating filtration variables simultaneously in isolated rat lung lobes in zone 3 conditions (pulmonary arterial pressure > pulmonary venous pressure > alveolar pressure). we used krebs ... | 1996 | 8888508 |
| development of cardiovascular responses to hypoxia in larvae of the frog xenopus laevis. | cardiovascular responses (blood pressure, heart rate, stroke volume, cardiac output, and peripheral vascular resistance) to acute hypoxia (po2 = 70 mmhg) in developing larvae of xenopus laevis from nieuwkoop-faber (nf) stage 45 and up to newly metamorphosed froglets were investigated. the results revealed two distinct response patterns to acute hypoxia in "early" (nf stages 45-48 and 49-51) and "late" (nf stages 52-53, 54-57, and 58-62) larval xenopus. the early larvae responded to acute hypoxia ... | 1996 | 8897981 |
| mechanism of 5-hydroxytryptamine-induced coronary vasodilation assessed by direct detection of nitric oxide production in guinea-pig isolated heart. | 1. we assessed whether a submaximal concentration (1 microm) of 5-hydroxytryptamine (5-ht) releases nitric oxide (no) from the coronary endothelium in guinea-pig perfused heart (n = 5 or 6/group) by direct detection of no in coronary effluent, and determined whether this accounts for the associated coronary dilation. we also tested whether saponin is a selective and specific tool for examining the role of this mechanism in mediating agonist-induced coronary dilatation. 2. continuous 5 min perfus ... | 1996 | 8904647 |
| transport of tracer albumin from peritoneum to plasma: role of diaphragmatic, visceral, and parietal lymphatics. | using a technique to acutely seal off various parts of the peritoneal membrane surface, with or without evisceration, we investigated the role of diaphragmatic, visceral, and parietal peritoneal lymphatic pathways in the drainage of 125i-labeled albumin (risa) from the peritoneal cavity to the plasma during acute peritoneal dialysis in artificially ventilated rats. the total risa clearance out of the peritoneal cavity (cl) as well as the portion of this cl reaching the plasma per unit time (cl-- ... | 1996 | 8928859 |
| digital starling forces and hemodynamics during early laminitis induced by an aqueous extract of black walnut (juglans nigra) in horses. | starling forces and hemodynamics in the digits of 5 horses were studied during early laminitis induced by oral administration of an aqueous extract of black walnut (juglans nigra). the black walnut extract was prepared from heartwood shavings and was administered by nasogastric tube. heart and respiratory rates, rectal temperature, central venous and arterial pressures, digital pulses, and signs of lameness were monitored. blood samples were collected for determination of wbc count, hemoglobin c ... | 1995 | 8928952 |
| characteristics of the glomerular capillary membrane of the rat kidney as a hydrated gel. i. hypothetical structure. | it is suggested that the glomerular capillary membrane constitutes a flexible gel, where negative charges fixed to the matrix of the membrane account for the maintenance of its integrity. in this model, the hydrostatic pressure throughout the membrane is assumed to equal the glomerular capillary pressure. pglom. of 56.7 mmhg. on the plasma side of the membrane, the charge-induced electro-osmotic pressure therefore has to balance the colloid osmotic pressure of glomerular plasma, and on its bowma ... | 1996 | 8931764 |
| [frank-starling mechanism and the 1st temporal derivative of ventricular pressure]. | | 1996 | 8935691 |
| circuit factors in the high cardiac output of sepsis. | the increase of cardiac output (co) in sepsis must be matched by an increase in venous return. our goal was to determine which of the determinants of venous return are responsible in volume-loaded and nonvolume-loaded pigs with endotoxemia. the determinants include stressed volume, venous compliance (cv), venous resistance (rvr) and right atrial pressure (pra). we also tested the effect of the nitric oxide (no) synthase inhibitor, n omega-nitro-l-arginine-methyl ester (l-name) after the hemodyna ... | 1996 | 8977991 |
| the pivotal role of john s. edkins in the discovery of gastrin. | john sydney edkins was born in london in 1863. after gaining two open scholarships, he attended caius college, cambridge and studied physiology under the tutelage of j.n. langley and m. foster. during this period he published on the chemical nature of pepsinogen with langley. after qualifying as a medical doctor, he worked in manchester before returning to london, where he succeeded e. klein as head of physiology at st. bartholomew's. for financial reasons he also worked part time at bedford col ... | 1997 | 8995084 |
| left ventricular adaptation to aortic regurgitation in conscious dogs. | cardiac failure as a result of valvular heart disease remains a major clinical problem that frequently leads to ventricular dysfunction, myocardial failure, and even death. the development of irreversible myocardial damage may be especially insidious in volume overload as a result of aortic or mitral regurgitation. | 1997 | 9011684 |
| septal function during left ventricular unloading. | left ventricular (lv) unloading with mechanical support devices alters biventricular geometry and impairs right ventricular (rv) contractility, but its effect on septal systolic function remains unknown. | 1997 | 9054866 |
| validation of different methods to compare isovolumic cardiac function in isolated hearts of varying sizes. | functional comparison of isolated hearts with different sizes has been difficult because function varies at different ventricular volumes. to date, no standard volume has been established. to determine the most accurate experimental approach, we tested five different methods to standardize volume in control hearts with different sizes but similar papillary muscle function and in hearts with concentric hypertrophy: intracardiac balloon volume (vb) = 120 microliters (m1). vb at diastolic pressure ... | 1997 | 9082860 |
| mycoplasmal conjunctivitis in a european starling. | bilateral conjunctivitis and episcleritis were identified in an adult european starling (sturnus vulgaris). a novel mycoplasma species, mycoplasma sturni, was isolated in pure culture from the conjunctiva of both eyes. the clinical presentation was similar to that of conjunctivitis in house finches (carpodacus mexicanus) caused by mycoplasma gallisepticum. however, the histologic lesions were distinct, by the presence of ulceration and by the absence of epithelial hyperplasia and lymphoplasmacyt ... | 1997 | 9131571 |
| inhomogeneities in wall stress measured by microergometry in the heart muscle in situ. | microergometry is a method which we have developed as a tool to measure local mesh-tension within the myocardial weave at any measuring site of both ventricles and the septum on the beating heart in situ. in a mapping procedure on pig and dog hearts, both in control conditions and in the hypertrophied state after aortic banding, local mesh-tension was measured in several areas and in up to eight depths proceeding from the epicardium to the endocardium: probe-to-fibre coupling is definitely more ... | 1997 | 9134624 |
| c-fos expression in the putative avian suprachiasmatic nucleus. | c-fos induction was investigated as a potential component in the avian photic entrainment pathway and as a possible means of locating the central pacemaker in birds. in both quail (coturnix coturnix japonica) and starlings (sturnus vulgaris) exposure to 1 h of light induced fos-lir in the visual suprachiasmatic nucleus but not in the medial suprachiasmatic nucleus. however, the degree of c-fos induction in the visual suprachiasmatic nucleus was similar at different circadian times despite the fa ... | 1997 | 9163930 |
| ca(2+)-dependent and ca(2+)-independent regulation of contractility in isolated human myocardium. | changes in contractile force of the myocardium may depend on changes in the intracellular ca2+ concentration, changes in the responsiveness of the myofibrils for ca2+, or a combination of both. we investigated in isolated muscle strip preparations from human nonfailing and endstage failing hearts the influence of physical (changes in preload, stimulation rate, or rhythm), and pharmacological interventions (alpha- or beta-adrenoceptor-stimulation, endothelin) on developed force of contraction and ... | 1997 | 9202847 |
| transgenic galphaq overexpression induces cardiac contractile failure in mice. | the critical cell signals that trigger cardiac hypertrophy and regulate the transition to heart failure are not known. to determine the role of galphaq-mediated signaling pathways in these events, transgenic mice were constructed that overexpressed wild-type galphaq in the heart using the alpha-myosin heavy chain promoter. two-fold overexpression of galphaq showed no detectable effects, whereas 4-fold overexpression resulted in increased heart weight and myocyte size along with marked increases ... | 1997 | 9223325 |
| the effects of nerve growth factor and anti-nerve growth factor antibody on the neuroendocrine reproductive system in the european starling sturnus vulgaris. | thyroidectomy of starlings causes them to remain in breeding condition indefinitely; deactivation of gonadotrophin-releasing hormone neurons that is characteristic of photorefractoriness does not occur. we hypothesise that a neurotrophin, whose presence or ability to function is dependent upon thyroid hormones, is somehow involved in this termination of gonadotrophin-releasing hormone release. nerve growth factor is one such candidate. mouse 7s-nerve growth factor dissolved in artificial cerebro ... | 1997 | 9251255 |
| basal release of nitric oxide augments the frank-starling response in the isolated heart. | the frank-starling response contributes to the regulation of cardiac output. the major underlying subcellular mechanism is a length-dependent change in myofilament responsiveness to ca2+. recent studies indicate that nitric oxide decreases myofilament responsiveness to ca2+ and modulates myocardial relaxation and left ventricular (lv) diastolic function. we therefore investigated the interaction between nitric oxide and the frank-starling response. | 1997 | 9286965 |
| contrasting effects of diethylenetriamine-nitric oxide, a spontaneously releasing nitric oxide donor, on pregnant rat uterine contractility in vitro versus in vivo. | the aim of the study was to investigate the in vitro (on tension) and in vivo (on intrauterine pressure) effects of a spontaneously releasing nitric oxide adduct, diethylenetriamine-nitric oxide, on rat uterine contractility. | 1997 | 9322644 |
| acid-induced increase in duodenal mucosal permeability is augmented by nitric oxide inhibition and vasopressin. | the aim of the study was to determine if and by what mechanism(s) nitric oxide inhibition modulates the susceptibility of the duodenum to hydrochloric acid-induced disturbances of mucosal integrity. a second aim was to investigate whether basal permeability is a determinant of epithelial acid barrier function. using an in situ duodenal perfusion model, mucosal permeability, alkaline secretion and morphology were investigated in anaesthetized rats. luminal perfusion with 50 mm hydrochloric acid i ... | 1997 | 9338517 |
| myocardial length-force relationship in end stage dilated cardiomyopathy and normal human myocardium: analysis of intact and skinned left ventricular trabeculae obtained during 11 heart transplantations. | the frank-starling-mechanism (fsm) was analyzed in isolated intact and skinned human left ventricular myocardium obtained from 11 heart transplantations (normal donor hearts (ndh), n = 8; dilated cardiomyopathy (dcm), n = 11). the new technique to utilize muscle strips from normal donor hearts which were actually implanted is described in detail. | 1997 | 9342433 |
| myocardial function in infarcted and remote regions early after infarction in man: assessment by magnetic resonance tagging and strain analysis. | early after infarction in the perfusion bed of the left anterior descending coronary artery, cine mri with spatial modulation of magnetization (spamm) tagging (7-mm grid) was used for short- and long-axis cardiac imaging. two-dimensional strain analysis of triangular finite elements was performed between end-diastole and end-systole. patients (n = 10) were compared with age-matched healthy subjects (n = 8). the anteroseptal region at midventricular level was considered representative for "infarc ... | 1997 | 9358455 |
| the contractile properties of the m. supracoracoideus in the pigeon and starling: a case for long-axis rotation of the humerus | wing upstroke in birds capable of powered flight is kinematically the most complicated phase of the wingbeat cycle. the m. supracoracoideus (sc), generally considered to be the primary elevator of the wing, is a muscle with a highly derived but stereotyped morphology in modern flying birds. the contractile portion of the sc arises from a ventral sternum, but its tendon of insertion courses above the glenohumeral joint to insert on the dorsal surface of the humerus. to clarify the role of the sc ... | 1997 | 9359888 |
| changes in gonadotrophin-releasing hormone (gnrh-i) in the pre-optic area and median eminence of starlings (sturnus vulgaris) during the recovery of photosensitivity and during photostimulation. | changes in gnrh-i in the pre-optic (poa) and medio-basal (mbh) areas of the hypothalamus and in pituitary and plasma lh were measured in starlings (sturnus vulgaris) during the recovery of photosensitivity under short days, and following photostimulation at various times during the recovery of photosensitivity. during exposure to short days there was a significant increase in gnrh-i in the poa, with the first detectable increase after only 10 days. there was no increase in gnrh-i in the mbh or i ... | 1997 | 9370960 |
| estimation of distribution parameters of some avian parasites. | occurrence of nematodes (mostly dominating and common species of porrocaecum ensicaudatum and p. semiteres) in host populations of birds (turdus merula, t. philomelos, sturnus vulgaris and scolopax rusticola) was summarized in frequency distributions, and tests of agreement with the poisson model as well as the modified binomial have been computed. comparisons of the observed frequencies with the expected ones showed the high values (3--257) of the coefficient of dispersion, the so-called "overd ... | 1997 | 9374592 |
| the frank-starling mechanism is not mediated by changes in rate of cross-bridge detachment. | we tested the hypothesis that the frank-starling relationship is mediated by changes in the rate of cross-bridge detachment in cardiac muscle. we simultaneously measured isometric force development and the rate of atp consumption at various levels of ca2+ activation in skinned rat cardiac trabecular muscles at three sarcomere lengths (2.0, 2.1, and 2.2 microns). the maximum rate of atp consumption was 1.5 nmol.s-1.microliter fiber vol-1, which represents an estimated adenosinetriphosphatase (atp ... | 1997 | 9374781 |
| model for a one-step plasma treatment device: feasibility of cholesterol removal. | a self-contained plasmapheresis device based on starling flow has been proposed. a computer model was developed to describe the device performance, and a device using conventional cellulose tri-acetate (cta) fibers was modeled. predicted pressure drops and ultrafiltration flow agreed well with measurements using bovine blood in prototype devices made with cta fibers. the model predicted the expected starling flow and predicted the observed high hematocrit region near the fiber wall and a layer o ... | 1997 | 9386837 |
| [effect of lisinopril on cardiac parameters and mortality after myocardial infarction in rats]. | to analyse the effect of early (< 24h) administration of lisinopril on ventricular remodeling and mortality after myocardial infarction (mi) in rats. | 1997 | 9435355 |
| mechanism of macromolecule concentration in collecting lymphatics in rat mesentery. | the mechanism by which macromolecular contents are concentrated during lymph transport was investigated in the collecting lymphatics of the mesentery of the rat. to examine changes in the concentration of lymph macromolecular tracer (fluorescein isothiocyanate-tagged dextran, mw 148,900) in the rhythmically contractile lymphatics, we quantified the fluorescence intensity of the lymph tracer using an intravital microscopy system with single slit-laser (20 microns in thickness) epi-illumination, r ... | 1997 | 9441890 |
| synchronization by low-amplitude light-dark cycles of 24-hour pineal and plasma melatonin rhythms of hatchling european starlings (sturnus vulgaris). | in young european starlings, as in other avian species, high-amplitude 24-hr rhythms in plasma and pineal melatonin are already present around the time of hatching. in chickens this rhythmicity results at least partly from the light sensitivity of the melatonin-producing and -secreting system. in contrast to the chicken, the starling is a hole-nesting bird, and it seemed questionable whether the low light intensities in the nest are sufficient to synchronize perinatal melatonin rhythms. we there ... | 1997 | 9462849 |
| biomechanical characteristics of unconditioned and conditioned latissimus dorsi muscles used for cardiocirculatory assistance. | an understanding of the biomechanical characteristics of striated skeletal muscles involved in cardiocirculatory assistance is a prerequisite to assess their efficacy and to evaluate their haemodynamic benefits. six goats had their latissimus dorsi muscles evaluated by isometric strain gauge testing. total tension, and both active and passive force development at different preloads were measured. the relationship between muscle impedance and starting length was also studied. four additional musc ... | 1997 | 9464610 |
| [the technical construction of a computer-supported measuring unit for in-vivo capillary pressure measurement in human nail fold capillaries]. | capillary pressure (cp) is an important determinant of microvascular function. according to frank starling, it governs not only the viscosity of the blood and the permeability of the capillary membrane, but also filtration and reabsorption in the microvascular bed. despite its great significance, the technique of cp measurement is employed in only a few laboratories throughout the world owing to the technical difficulties involved in carrying out such measurements. the first attempts were made b ... | 1997 | 9490121 |
| the role of interstitial starling forces in the pathogenesis of burn edema. | the formation and sustainability of burn edema require substantial change in net microvascular forces. we directly measured interstitial hydrostatic pressure (pi) and total interstitial absorptive pressure (pi + iii), in dermis of anesthetized sheep, before and after a 70% to 85% total body surface area scald and during fluid resuscitation. the most rapid change occurred in pi in the burn wound, which rapidly decreased from its baseline value of approximately -2 mm hg to -11 mm hg in the first 5 ... | 1998 | 9502017 |
| contribution of synchronized atrial systole to left ventricular contraction in the newborn pig heart. | synchronized atrial contraction may be much more important in the newborn, who has a faster heart rate and a less compliant ventricle, than in the adult. we therefore investigated the extent by which synchronized atrioventricular contraction contributes to cardiac output and cardiac work in a neonatal circulation, and whether this effect can be fully explained by the starling mechanism. in neonatal piglets, left ventricular pressure and volume (conductance catheter) were measured during atrial a ... | 1998 | 9505270 |
| shortening versus isometric contractions in isolated human failing and non-failing left ventricular myocardium: dependency of external work and force on muscle length, heart rate and inotropic stimulation. | for reasons of simplicity, studies on isolated human myocardium have been conducted using exclusively isometric contractions, although positive inotropic interventions may differently influence force development, extent of shortening and myocardial work performance. we investigated human left ventricular failing and non-failing preparations comparing isometric versus isotonic, i.e., shortening contractions. | 1998 | 9539857 |
| preserved frank-starling mechanism in human end stage heart failure. | the goal of the present study was to examine the ability of failing myocardium to respond to enhanced preload with an increase in force development. | 1998 | 9614508 |
| length dependence of calcium- and force-transients in normal and failing human myocardium. | two questions were analysed: (1) is the frank-starling mechanism operative in failing human myocardium? (2) are length-dependent changes in force accompanied by length-dependent changes in intracellular calcium transients in human myocardium? | 1998 | 9618236 |
| right ventricular function after brain death: response to an increased afterload. | a major cause of early postoperative morbidity and mortality after cardiac transplantation is right ventricular (rv) failure which is attributed to the inability of the donor's rv to acutely compensate for the recipient's elevated pulmonary vascular resistance. this study was performed to determine: (1) the acute effects of brain death on the rv function; and (2) the adaptation potential of the rv to a progressive increase in rv afterload. | 1998 | 9641345 |
| cryptococcosis and starling nests. | | 1998 | 9643699 |
| [new aspects of the pathophysiology of heart failure]. | the progression of heart failure is related to activation of neuroendocrine hormone systems. on the level of the myocardium, they contribute to hypertrophy, dilation and remodeling of the ventricles. in addition, vascular alterations with endothelial dysfunction and alterations of skeletal muscle contribute to clinical symptoms of heart failure patients. changes in ventricular geometry during the progression of cardiac diseases are associated with specific subcellular alterations on the level of ... | 1998 | 9654696 |
| hair cell morphology and innervation in the basilar papilla of the emu (dromaius novaehollandiae). | the emu, being a member of the rather primitive bird group of the palaeognathid ratitae, may reveal primitives features of the avian basilar papilla. there are, however, no qualitative differences with the papillae of other birds such as the chicken or the starling. there are only quantitative differences in the continuous morphological gradients (such as hair cell height, stereovillar height) from neural to abneural, and from the base to the apex of the papilla. only few (about two in the emu) ... | 1998 | 9682814 |
| transmyocardial laser-revascularization: experimental studies on prolonged acute regional ischemia. | this experimental study in pigs was undertaken to answer the question whether tmlr after acute myocardial infarction may improve regional myocardial perfusion, left ventricular function and diminish myocardial necrosis in the area at risk. | 1998 | 9686802 |
| muscle metaboreflex increases ventricular performance in conscious dogs. | ischemia of active skeletal muscle stimulates neuronal afferents within the muscle, which elicits a reflex increase in systemic arterial pressure (sap), heart rate (hr), and cardiac output (co) termed the muscle metaboreflex. we investigated whether activation of the muscle metaboreflex elicits increases in ventricular performance using conscious, chronically instrumented dogs trained to run on a treadmill (3.2 km/h, 0% grade). the muscle metaboreflex was activated via progressive partial vascul ... | 1998 | 9688917 |
| long-term hypothyroidism causes decreased bone competence in male european starlings, sturnus vulgaris. | male european starlings were thyroidectomised and held on either short or long day photoperiods. intact euthyroid control birds were also held on either short or long days to control for differences in reproductive condition. femora of birds from each group were sampled following plasma thyroxine measurement. hypothyroidism caused decreased bone mechanical competence in starlings, as determined by vickers microhardness testing. it was also found that transfer from short to long daylengths caused ... | 1998 | 9697325 |
| flap flow and cardiac output as functions of pulmonary artery wedge pressure: experimental study in the pig. | cardiac output (co) is redistributed during hypovolemia, but it has not been clearly documented how this influences flap perfusion. simultaneous changes in perfusion of a muscle flap and co as modulated by reductions in cardiac filling pressure were compared in a pig model. the hypothesis was that flap flow (ff) would remain relatively constant as co was reduced, according to the frank-starling curve. under general anesthesia, five domestic pigs were utilized. following right carotid artery cann ... | 1998 | 9714037 |
| evidence for constitutive release of nitric oxide in the venous circuit of pigs. | to determine whether the venous circuit constitutively produces nitric oxide (no), we infused the no synthase inhibitor, ng-nitro-l-arginine methyl ester (l-name) into anesthetized and mechanically ventilated pigs and measured venous circuit parameters. we measured cardiac output (q) by thermodilution and obtained arterial (part), central venous pressure (in the inferior vena cava), right atrial (pra), pulmonary artery (pap), and pulmonary capillary wedge pressures. a balloon was transiently inf ... | 1998 | 9733348 |
| fluid dynamics of gingival tissues. | gingival hydraulic interstitial pressure was measured with glass micropipettes in 18 anesthetized rabbits at the level of the free gingiva, attached gingiva and oral mucosa facing the incisors and molar teeth. samples of gingival interstitial tissue fluid were also collected by inserting nylon wicks in the subepithelial layer of the oral mucosa. colloid osmotic pressure of interstitial fluid samples was measured with an osmometer whose membrane had a molecular cutoff of 30 kd. hydraulic intersti ... | 1998 | 9777583 |
| nitric oxide enhances the inotropic response to beta-adrenergic stimulation in the isolated guinea-pig heart. | nitric oxide (no) exerts several effects on myocardial contraction, including enhancement of relaxation and diastolic function, modulation of beta-adrenergic inotropic responses, and inotropic effects in the absence of agonist pre-stimulation. different effects have been observed in different species and preparations, and it is unclear whether they are species- or preparation-specific, or whether they represent a range of responses that can manifest in most mammalian species. we therefore examin ... | 1998 | 9782370 |
| imaging birds in a bird cage: in-vivo fse 3d mri of bird brain. | an in-vivo magnetic resonance imaging (mri) procedure is described that allows one to obtain three-dimensional high quality images of the entire brain of small birds such as the canary (20 g) and the starling (75 g) with an image resolution of 0.1 mm (58-113 microm, dependent on the size of the imaged bird). the entire imaging procedure took about 2 h after which the birds recovered from anaesthesia uneventfully and could be reused for subsequent additional imaging. this non invasive mri techniq ... | 1998 | 9794286 |
| mechanisms of stretch-induced changes in [ca2+]i in rat atrial myocytes: role of increased troponin c affinity and stretch-activated ion channels. | to study the effects of stretch on the function of rat left atrium, we recorded contraction force, calcium transients, and intracellular action potentials (aps) during stretch manipulations. the stretch of the atrium was controlled by intra-atrial pressure. the frank-starling behavior of the atrium was manifested as a biphasic increase of the contraction force after increasing the stretch level. the development of the contraction force after step increase of the stretch (intra-atrial pressure fr ... | 1998 | 9831710 |
| role of experience for language-specific functional mappings of vowel sounds. | studies involving human infants and monkeys suggest that experience plays a critical role in modifying how subjects respond to vowel sounds between and within phonemic classes. experiments with human listeners were conducted to establish appropriate stimulus materials. then, eight european starlings (sturnus vulgaris) were trained to respond differentially to vowel tokens drawn from stylized distributions for the english vowels /i/ and /i/, or from two distributions of vowel sounds that were ort ... | 1998 | 9857515 |
| effect of flow on hydraulic conductivity and reflection coefficient of rabbit mesentery. | to measure the hydraulic conductivity and reflection coefficient for albumin, as defined by the starling equation, in rabbit mesentery. | 1998 | 9866117 |
| determinants of myocardial performance after blunt chest trauma. | this study investigates whether factors that determine myocardial performance (preload, afterload, heart rate, and contractility) are altered after isolated unilateral pulmonary contusion. | 1998 | 9867038 |
| an improved isolated, left ventricular ejecting, murine heart model. functional and metabolic evaluation. | an improved, isolated, left ventricular-ejecting, murine heart model is described and evaluated. special attention was paid to the design and impedance characteristics of the artificial aortic outflow tract and perfusate composition, which contained glucose (10 mm plus insulin) and pyruvate (1.5 mm) as substrates. temperature of the isolated perfused hearts was maintained at 38.5 degrees c. during antegrade perfusion (preload 10 mm hg, afterload 50 mm hg, 2.5 mm ca2+) proper design of the aortic ... | 1999 | 9929557 |
| cellular mechanisms for the slow phase of the frank-starling response. | following a step increase in sarcomere length, isometric cardiac muscle tension increases instantaneously by the frank-starling mechanism. in isolated papillary muscle and myocytes, there is an additional significant rise in developed tension over the following 15 min due to an unknown mechanism. this slow change in tension could not be explained by mechanical heterogeneity of the muscle preparations or by an increase in myofilament sensitivity to ca2+. the slow change in tension was not depende ... | 1998 | 9988000 |
| [swarms of starlings in basel: a natural phenomenon, a nuisance or a health risk?]. | a natural phenomenon, molestation or a health risk? for the last two decades an avenue in the centre of basel (altrheinweg, klybeckquartier) is known as site for overnight accommodation and assembly of starlings (sturnus vulgaris) during autumn. the nightly visitors cause an immense contamination that directly affects a nursery and a primary school. the aim of the present study was the evaluation of the health risk for the population due to the starlings' droppings, particularly for the children ... | 1998 | 10024775 |
| effects of isoproterenol on myocardial structure and function in septic rats. | in this study we sought to determine the effect of sepsis on two sequelae of prolonged (24-h) beta-agonist administration, myocardial hypertrophy and catecholamine-induced cardiotoxicity. sprague-dawley rats were randomized to cecal ligation and perforation (clp) or sham study groups and then further randomized to receive isoproterenol (2.4 mg. kg-1. day-1 iv) or placebo treatment. at 24 h, myocardial function was assessed by using the langendorff isolated-heart technique or the heart processed ... | 1999 | 10066715 |
| reflection coefficient for albumin and capillary fluid permeability in cat calf muscle after traumatic injury. | surgery and traumatic injury are often followed by tissue oedema and a low plasma albumin concentration, indicating leakage of fluid and proteins from the intravascular to the interstitial space. transcapillary leakage can be referred to as an increase in capillary hydraulic conductance and/or a decrease in the reflection coefficient for plasma macromolecules. this study evaluates if time-dependent variations in the reflection coefficient for albumin and capillary hydraulic conductance can be co ... | 1999 | 10350231 |
| does the guinea-pig ileum obey the 'law of the intestine'? | 1. we report the first simultaneous mechanical reflex responses of the longitudinal muscle (lm) and circular muscle (cm) layers of the guinea-pig ileum following mucosal stimulation and distension in vitro. 2. dissection techniques were used to prevent mechanical interaction between the lm and cm layers both oral and anal to a stimulus site. 3. all graded stimuli produced graded contractions of both the lm and cm orally and anally to the stimulus. contractions occurred synchronously in the lm an ... | 1999 | 10358127 |
| length modulation of active force in rat cardiac myocytes: is titin the sensor? | the intrinsic cellular mechanisms by which length regulates myocardial contraction, the basis of the frank-starling relation, are uncertain. the aim of this work was to test the hypothesis that passive force, possibly via titin, participates in the modulation of ca2+ sensitivity of cardiac contractile proteins induced by stretch. titin degradation by a mild trypsin digestion modulated passive force induced by increasing from 1.9 to 2.3 microm sarcomere length in skinned rat cardiac cells. force- ... | 1999 | 10371696 |
| the divergence in the conception of pavlov and bayliss-starling concerning the function of the nervous system. | the history of the discoveries of the mechanisms of the pancreatic secretion is a fine example of the conflict of two schools and the concurrence of two concepts: the nerve control (pavlov and his co-workers) and the humoral control (bayliss and starling). only the synthesis of both conceptions brought about the most accurate model of the control mechanisms. | 1999 | 10377602 |
| mhc variation in birds and reptiles. | the major histocompatibility complex (mhc) has been studied in a multitude of mammals by now, but much less is known about its organisation and variation in other vertebrate species. the mammalian mhc is organised as a single gene cluster, but recent studies on birds suggest that this paradigm of mhc organisation has to be supplemented. the domestic chicken thus possesses two separate gene clusters which both contain mhc class i and class ii b genes, and we have shown that the ring-necked pheasa ... | 1998 | 10386396 |
| peep-induced pulmonary vasoconstriction in neonatal piglets: analysis by pressure-flow curves. | we analyzed the effect of two levels of positive end-expiratory pressure (peep: 10 and 15 cm h2o) on pulmonary hemodynamics in neonatal piglet lungs isolated in situ and perfused extracorporeally using pulmonary artery pressure-flow (pa/q) relationships. pulmonary artery pressure (pa) was measured at flow rates of 50, 75, 100, 125, and 150 ml/kg/min. pa/q relationship was evaluated by the slope of the pa/q plot and the zero-flow intercept pressure (pi). pa/q relationship with peep was studied be ... | 1999 | 10406045 |
| wall thickness referenced to myocardial volume: a new noninvasive framework for cardiac mechanics. | dimensional variables measured for study of left ventricular mechanics are subject to errors arising from difficulty in determining zero-stress dimensions for use as a reference. based on a method validated for measurements within individuals, we have devised an approach that facilitates comparison between individuals while minimizing random scatter. we define an exact mathematical index of strain, ln(h(0)/h), using wall thickness (h) referenced to extrapolated wall thickness at zero-luminal vol ... | 1999 | 10409577 |
| eastern equine encephalitis virus in birds: relative competence of european starlings (sturnus vulgaris). | to determine whether eastern equine encephalitis (eee) virus infection in starlings may be more fulminant than in various native candidate reservoir birds, we compared their respective intensities and durations of viremia. viremias are more intense and longer lasting in starlings than in robins and other birds. starlings frequently die as their viremia begins to wane; other birds generally survive. various aedes as well as culiseta melanura mosquitoes can acquire eee viral infection from infecte ... | 1999 | 10466964 |
| survey of pathogens and blood parasites in free-living passerines. | to determine the disease prevalence of free-living passerines, 1709 passerines were sampled from 38 different field sites in ohio. choanal and cloacal swabs were collected from each bird and cultured for the presence of pasteurella multocida, salmonella spp., and escherichia coli by standard microbiologic techniques. in addition, the serum from each bird was analyzed for the presence of antibodies to mycoplasma gallisepticum, mycoplasma synoviae, newcastle disease virus, and avian influenza viru ... | 1999 | 10494426 |
| means for load variation during echocardiographic assessment of the frank-starling relationship. | because minimally invasive methods of preload variation are not validated for load-insensitive indexes of cardiac performance, intravenous nitroglycerin (ntg), phenylephrine, and saline solution (vol) boluses were used in blocked and intact autonomic states to alter load and were compared with vena caval occlusion in the assessment of preload recruitable stroke work relationships between stroke work and left ventricular end-diastolic volume in dogs. in both autonomic states ntg and vol produced ... | 1999 | 10511647 |
| angiotensin iv has mixed effects on left ventricle systolic function and speeds relaxation. | a novel angiotensin receptor has been described and named at4. ligands for this receptor include the angiotensin ii (ang ii) metabolite ang ii (3-8), known as angiotensin iv (ang iv). there is 10-fold more at4 receptor than at1 receptor in rabbit myocardium. the at4 receptor has a high affinity for ang iv (ki in rabbit myocardium < 2 x 10(-9)) and similar ligands, but very low affinity for ang ii (ki in rabbit myocardium > 10(-6)). although several functions have been attributed to the novel ang ... | 1999 | 10533606 |
| restoring the remodeled enlarged left ventricle: experimental benefits of in vivo porcine cardioreduction in the beating open heart. | conceptual models have been used to assess the efficacy of cardioreduction (i.e., batista procedure) because in vivo models were not available. this study reproduces an experimental angiographic model of heart failure by placing a large pericardial patch to sphericalize the left ventricle. patch removal restored an elliptical normal cardiac shape. cardioreduction was evaluated in 20 mini-pigs on cardiopulmonary bypass. myocardial protection with a beating open method was used and cardioplegia wa ... | 1998 | 10543456 |
| a behavioral test of presbycusis in the bird auditory system. | absolute auditory thresholds were determined behaviorally in european starlings (sturnus vulgaris) between the age of 6 months and up to 13 years using a go/nogo procedure. the thresholds that we observed in individual starlings over a time period of 11 years showed no systematic increase over time. when comparing young starlings (age 6 to 12 months) with old starlings (age 8 to 13 years), we discovered no substantial age-related hearing loss. in the frequency range from 0.5 to 4 khz, the thresh ... | 1999 | 10545635 |
| a quantitative study of cochlear afferent axons in birds. | this paper is a comparative study of auditory-nerve morphology in birds. the chicken (gallus gallus), the emu (dromaius novaehollandiae) and the starling (sturnus vulgaris) were chosen as unspecialised birds that have already been used in auditory research. the data are discussed in comparison to a similar earlier study on the barn owl, a bird with highly specialised hearing, in an attempt to separate general avian patterns from species specialisations. average numbers of afferent fibres from 87 ... | 2000 | 10601718 |
| extracellular fluid and its proteins: dehydration, shock, and recovery. | this review highlights characteristics of extracellular fluid (ecf) that are often overlooked. ecf has, in addition to plasma and interstitial fluid (isf) surrounding cells, a third large compartment, the isf of skin and connective tissue. this acts as a reservoir that gives up ecf to plasma volume (pv) in order to sustain circulation in the event of either shock or dehydration. while starling forces drive filtration, ecf is returned to pv more by lymph and less by starling forces than previousl ... | 1999 | 10603162 |
| ventricular volume, chamber stiffness, and function after anteroapical aneurysm plication in the sheep. | the success of left ventricular aneurysm plication depends on how the procedure affects both end-systolic elastance and diastolic compliance and how those changes affect ventricular function (stroke work/end-diastolic volume [prsw] and stroke volume/end-diastolic pressure [starling] relationships). | 2000 | 10612769 |
| effect of ionic strength on length-dependent ca(2+) activation in skinned cardiac muscle. | the length-dependence of myofilament ca(2+) sensitivity is considered to be an important component of the steep force-length relationship in cardiac muscle (frank-starling relation). recent studies suggest that ca(2+) sensitivity is a function of the number of strong-binding cross-bridge interactions formed at a given sarcomere length. however, the length-dependent step in the thin filament activation process is still unknown. this study was designed to test the hypothesis that sarcomere length ... | 1999 | 10640440 |
| improved contractile performance of right ventricle in response to increased rv afterload in newborn lamb. | pulmonary hypertension results in an increased afterload for the right ventricle (rv). to determine the effects of this increased afterload on rv contractile performance, we examined rv performance before and during 4 h of partial balloon occlusion of the pulmonary artery and again after releasing the occlusion in nine newborn lambs. rv contractile performance was quantified by indexes derived from systolic rv pressure-volume relations obtained by a combined pressure-conductance catheter during ... | 2000 | 10644589 |
| kinematics and mechanics of ground take-off in the starling sturnis vulgaris and the quail coturnix coturnix. | the mechanics of avian take-off are central to hypotheses about flight evolution, but have not been quantified in terms of whole-body movements for any species. in this study, i use a combination of high-speed video analysis and force plate recording to measure the kinematics and mechanics of ground take-off in the european starling sturnis vulgaris and the european migratory quail coturnix coturnix. counter to hypotheses based on the habits and morphology of each species, s. vulgaris and c. cot ... | 2000 | 10648214 |
| effects of positive end-expiratory pressure ventilation on cerebral venous pressure with head elevation in dogs. | mechanical ventilation with positive end-expiratory pressure (peep) may prevent venous air embolism in the sitting position because cerebral venous pressure (pcev) could be increased by the peep-induced increase in right atrial pressure (pra). whereas it is clear that there is a linear transmission of the peep-induced increase in pra to pcev while the dog is in the prone position, the mechanism of the transmission with the dog in the head-elevated position is unclear. we tested the hypothesis th ... | 2000 | 10658034 |
| batista procedure: elliptical modeling against spherical distention. | batista's cardio-reduction of mass and diameter changes the geometry of the left ventricle (lv). this in vivo study explores the lv changing from spherical distention to elliptic modeling. | 2000 | 10735412 |
| modulation of starling forces and muscle fiber maturity permits adenovirus-mediated gene transfer to adult dystrophic (mdx) mice by the intravascular route. | duchenne muscular dystrophy (dmd) and other inherited myopathies lead to progressive destruction of most skeletal muscles in the body, including those responsible for maintaining respiration. dmd is a fatal disorder caused by defects in the dystrophin gene. recombinant adenovirus vectors (adv) are considered a promising means for therapeutic delivery of a functional dystrophin gene to dmd muscles. if adv-mediated dystrophin gene replacement in dmd is to be successful, development of a systemic d ... | 2000 | 10757350 |
| length-tension relationships of sub-epicardial and sub-endocardial single ventricular myocytes from rat and ferret hearts. | in vivo the sub-epicardial myocardium (epi) and sub-endocardial myocardium (endo) operate over different ranges of sarcomere length (sl). however, it has not been previously shown whether epi and endo work upon different ranges of the same or differing length-tension curves. we have compared the sl-tension relationship of intact, single ventricular epi and endo myocytes from rat and ferret hearts. cells were attached to carbon fibres of known compliance in order to stretch them and to record for ... | 2000 | 10775479 |
| length-dependence of cross-bridge mediated activation of the cardiac thin filament. | length-dependent ca(2+)activation of the thin filament plays a critical role in the steep force-length relationship of cardiac muscle (frank-starling relation). recent evidence indicates that the increase in myofilament ca(2+)sensitivity and ca(2+)-troponin c affinity that occurs with increase in sarcomere length results from a cooperative activation of the thin filament by attached cross-bridges. at short sarcomere length the ca(2+)sensitivity is lower because the access of cross-bridges for ac ... | 2000 | 10775487 |
| [the role of common starlings (sturnus vulgaris) in the epidemiology of bacterial, potentially human pathogenic, disease agents]. | since a long time a public garden in basel is known as a site for overnight accommodation and assembly of starlings. the birds cause an immense faecal contamination of the park and the neighbouring district. a nursery and a primary school are directly affected. to evaluate the health risk coming from the starlings droppings for the population, particularly for the children and to assess the role of starlings in the transmission of diseases to humans and in the epidemiology of human diseases the ... | 2000 | 10804841 |
| extracorporeal circulation exacerbates microvascular permeability after endotoxemia. | extracorporeal life support without prior inflammatory stimuli results in a modest increase in microvascular permeability. initiating ecls after shock, sepsis, or hypoxia results in marked increases in interstitial fluid and total body water. we sought to determine whether an inflammatory stimulus prior to initiating ecls increases microvascular permeability to protein. | 2000 | 10816349 |
| effects of selectin-sialyl lewis blockade on mesenteric microvascular permeability associated with cardiopulmonary bypass. | cardiopulmonary bypass is associated with an inflammatory response that is associated with a neutrophil-mediated microvascular barrier injury. we studied the effects of blocking neutrophil-endothelial tethering on microvascular permeability and edema formation during cardiopulmonary bypass. using a selectin antagonist that prevents interactions with their ligands, we hypothesized that there would be less neutrophil infiltration into the tissue and a reduction in microvascular permeability and ed ... | 2000 | 10838545 |
| blood pressure control in a larval amphibian, xenopus laevis. | the regulation of arterial pressure in early vertebrate embryos and larvae with non-innervated hearts is poorly understood. we used nanoliter intravascular injections in anaesthetized xenopus laevis larvae (stage 49-51) to assess their ability to maintain arterial pressure in the face of a volume load. injections of saline and hetastarch (a volume expander) were made into the ventricle. arterial pressure, end-diastolic ventricular volume, end-systolic ventricular volume and heart rate were measu ... | 2000 | 10851121 |
| [pathophysiological basis of heart failure]. | the progression of heart failure is related to local and systemic neuroendocrine activation. on the level of the myocardium, neuroendocrine activation (angiotensin ii, endothelin, aldosterone, norepinephrine) as well as mediators of inflammation and free oxygen radicals contribute to hypertrophy, dilation and remodeling of the ventricles. in addition, vascular endothelial dysfunction and alterations of skeletal muscle contribute to clinical symptoms of heart failure patients. changes in ventricu ... | 2000 | 10859987 |
| lack of gonadotrophin-releasing hormone (gnrh) neuron response to decreasing photoperiod in thyroidectomized male starlings (sturnus vulgaris). | exposure of starlings to long days initially causes reproductive maturation, but eventually leads to photorefractoriness. during photorefractoriness, gonadotrophin-releasing hormone (gnrh) decreases in the gnrh cell bodies and fibers emanating from these to the median eminence, circulating gonadotrophin concentrations decrease to a minimum, and the gonads regress. thyroidectomy profoundly affects these photoperiodic responses. in chronically thyroidectomized starlings, gonadal responses to chang ... | 2000 | 10861552 |
| effect of protein kinase a on calcium sensitivity of force and its sarcomere length dependence in human cardiomyocytes. | we investigated whether the frank-starling mechanism is absent or preserved in end-stage failing human myocardium and if phosphorylation of contractile proteins modulates its magnitude through the sarcomere length-dependence of calcium sensitivity of isometric force development. | 2000 | 10912459 |
| reflex responses from the main pulmonary artery and bifurcation in anaesthetised dogs. | this study was undertaken to determine the reflex cardiovascular and respiratory responses to discrete stimulation of pulmonary arterial baroreceptors using a preparation in which secondary modulation of responses from other reflexes was prevented. dogs were anaesthetised with -chloralose, artificially ventilated, the chests widely opened and a cardiopulmonary bypass established. the main pulmonary arterial trunk, bifurcation and extrapulmonary arteries as far as the first lobar arteries on each ... | 2000 | 10918080 |
| absence of reflex vascular responses from the intrapulmonary circulation in anaesthetised dogs. | the aim of this investigation was to determine whether reflex cardiovascular responses were obtained to localised distension of the intrapulmonary arterial and venous circulations in a preparation in which the stimuli to other major reflexogenic areas were controlled and the lung was shown to possess reflex activity. dogs were anaesthetised with -chloralose, artificially ventilated, the chests widely opened and a cardiopulmonary bypass established. the intrapulmonary region of the left lung was ... | 2000 | 10918081 |
| [mechanical human heart work in a newborn infant]. | the echo- and dopplerography of newborn infants up to 10-day age revealed that their heart work capacity was about 6 wt, relative capacity--25 wt/100 g of ventricular mass. these data correspond to those of adult humans. the frank-starling mechanism was corroborated. | 2000 | 10955306 |
| a baroreflex model of short term blood pressure and heart rate variability. | parameters based on heart rate variability alone or on both heart rate and blood pressure variability (baroreflex sensitivity) are becoming increasingly clinical relevant. nevertheless a complete insight in physiological mechanisms underlying these parameters is still lacking. a computer model may help to fill up some of the gaps. we present a model which consists of a simple beat-to-beat hemodynamic part (starling heart and windkessel) linked to a detailed continuous modelled neural control par ... | 2000 | 10977598 |
| end-systolic pressure-diameter relation of the left ventricle during transient and sustained elevations of blood pressure. | to assess the effect of transient and sustained variations in cardiac load on the values of the end-systolic pressure-diameter relation (espdr) of the left ventricle. | 2000 | 10983017 |