bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism by Which Serotonin, Norepinephrine and Reserpine Cause Central Vasomotor Inhibition
Authors: KANEKO Y. , McCUBBIN J. W. , PAGE IRVINE H. 
Published: June 2012

Several vasoconstrictor drugs and reserpine administered into a cerebral lateral ventricle inhibited the reflex pressor response to occlusion of the common carotid arteries in both anesthetized and unanesthetized dogs. This effect was opposed by central administration of the vasodilator drugs, nitroprusside and histamine. Serotonin, norepinephrine and their precursors, 5-hydroxytryptophan and 3,4-dihydroxyphenylalanine, and reserpine caused lowering of arterial pressure and slowing of heart rate as well as inhibition of the carotid occlusion response; angiotensin and vasopressin did not. The central inhibitory effect of norepinephrine was opposed by phentolamine; that of 5-hydroxytryptophan was not affected by lysergic acid diethylamide or its brom derivative.
Cooling of cerebrospinal fluid, which presumably caused local vasoconstriction, also caused inhibition of the carotid occlusion response, hypotension and bradycardia, and these effects were counteracted by central injection of vasodilator drugs. Warming of cerebrospinal fluid, presumably associated with local vasodilation, opposed the central inhibitory effect of vasoconstrictor drugs and of reserpine.
In view of the consistently opposite effects of vasoconstrictor and vasodilator drugs and procedures on central vasomotor sympathetic activity, it is tentatively concluded that these effects depend on change in local blood flow. The acute cardiovascular effects of reserpine of central origin are probably due to local decrease of tissue perfusion caused by serotonin, norepinephrine or other vasoconstrictor agent released from a bound to an active form.
Epicardial Excitation Pattern as Observed in the Isolated Revived and Perfused Fetal Human Heart
Authors: DURRER D. , BÜLLER J. , GRAAFF P. , Lo G. I. , MEYLER F. L. 
Published: June 2012

The resuscitated fetal human heart can be used as an experimental tool for the investigation of the excitatory process in the human heart. During perfusion the configuration of the epicardial electrocardiograms does not change appreciably. For accurate recording permitting a detailed analysis, the use of a high-fidelity oscillograph is absolutely necessary, otherwise no identification of the rapid portion of the intrinsic deflection can be made. The heart is suspended in an homogenous volume conductor at 37 C. and perfused with fluid matching as closely as possible the composition of the extracellular fluid.
The morphology of the unipolar complexes is difficult to describe adequately. At the anterior side of the right and left ventricles rS complexes are found. Some parts of the left ventricular wall and posteroapical region of the left ventricle show QR complexes. In the area bordering the A-V groove one-third the distance from apex to basis, deep Q waves and even QS complexes are found. The relatively late intrinsic deflection here points to late excitation of this region. In regions neighboring the A-V groove, the Q wave diminishes in size and the R increases. The left posterior part of the left atrium is activated latest in the atrial cycle. The epicardial excitation pattern is surprisingly simple. The excitation wave reaches the region of attachment of the right anterior papillary muscle first, then spreads radially with varying velocity across the left ventricle towards the posterobasal region, while another wave spreads simultaneously across the right ventricle towards the same region. There is, therefore, a double envelopment of the epicardial surface. A comparison of the complexes having an intrinsic deflection occurring at the same time shows conclusively that, even over the same ventricle, the morphology of these complexes may be completely different. Thus the excitation time does not determine the morphology of the complexes. There is no typical right or left ventricular pattern. There appears to be no relationship between thickness of the heart wall and height of the R wave.
Flow, Pressure, and Volume Relationships in the Pulmonary Circulation During Exercise in Normal Dogs and Dogs with Divided Left Pulmonary Artery
Authors: MARSHALL ROBERT J. , WANG YANG , SEMLER HERBERT J. , SHEPHERD JOHN T. 
Published: June 2012

The effect of exercise on the pulmonary circulation was studied in a group of 6 intact dogs and in a second group of 4 subjected to ligation and division of the left pulmonary artery. Observations were made with the dogs standing and running on a horizontal treadmill up to the maximal speed they could maintain for periods of at least 2 minutes, usually 12 or 14 km./hr.
Continuous records were made of the difference in pressure between the main pulmonary artery (PA) and a pulmonary-artery wedge (PAW) position. Cardiac output was determined by the indicator-dilution method, with injection of indocyanine (cardiogreen) dye into the main pulmonary artery and continuous sampling from the root of the aorta. The mean transit time of indicator betweell the pulmonary and aortic valves was obtained from the dilution curves, a correction being made for the transit time through the sampling apparatus. From these measurements the blood volume of the lungs and left heart chambers was derived.
In the intact dogs, cardiac output increased approximately threefold from rest to severe exercise. There was an increase of only 12 per cent to 50 per cent in PA minus PAW pressure. Thus a continued fall occurred in pulmonary vascular resistance. The blood volume of the lungs and left heart of 3 intact dogs was measured. In 2 it did not change through the range of activity, and in the third the increase with maximal exercise was 18 per cent.
The dogs with ligated left pulmonary artery also showed a threefold increase in output with severe exercise. Since the entire output passed through a single lung, the effect on the pulmonary vessels was comparable to that of a sixfold increase in output in a normal dog. Despite such large flows, in 3 of 4 dogs the difference between PA and PAW pressure rose only 37 per cent to 50 per cent. The volume of blood in the lungs and left heart was unchanged between rest and 8 km./hr., and at higher speeds showed a 0 per cent to about 20 per cent increase.
Evaluation of the Pressor, Cardiac, and Renal Hemodynamic Properties of Angiotensin II in Man
Authors: FINNERTY FRANK A. , MASSARO GLORIA DECARLO , CHUPKOVICH VICTOR , TUCKMAN JOHN 
Published: June 2012

These data demonstrate that in normal subjects angiotensin II is 10 times as potent as norepinephrine, which it resembles hemodynamically. An increase in the systolic pressure is associated with significant increase in diastolic pressure, increase in venous pressure, decrease in heart rate, slight decrease in cardiac output with striking increase in total peripheral resistance, decrease in renal blood flow, decreased glomerular filtration rate, increase in filtration fraction, arid slight decrease in urinary volume.
Preliminary studies of patients in shock suggest that angiotensin II is two or three times as potent as norepinephrine. Continuous administration is not associated with the development of resistance or tachyphylaxis, nor does sloughing of tissues occur when there is leakage outside the vein.
Factors Affecting Myocardial Storage and Release of Catecholamines
Authors: KAKO KYOHEI , CHRYSOHOU ATHANASIOS , BING RICHARD J. 
Published: June 2012

The factors affecting myocardial storage and release of catecholamines were investi gated. The catecholainine concentration of heart muscle of normal dogs averaged 0.617 g. per Gm. of heart muscle. Ventricular tachycardia, fibrillation, and reserpine caused a slight reduction in myocardial catechol amine concentration, while nicotine resulted in a slight increase. Iproniazid was without effect. The injection of the amino acid, Dopa, and of the combinatiou of Dopa and iproni azid, resulted in a significant elevation of catecholamines in heart muscle.
In animals pretreated with Dopa and iproniazid, nicotine caused a significant in crease in myocardial catecholaniines. It is likely that stimulation of the adrenal medulla and sympathetic nerve endings by nicotine elevated catecholamine levels in blood, with subsequent storage in the heart and other organs.
Coronary Driving Pressure and Vasomotor Tonus as Determinants of Coronary Blood Flow
Authors: CROSS CECIL E. , RIEBEN P. ANDRE , SALISBURY PETER F. 
Published: June 2012

A method is described that measures the contribution of coronary vasomotor tonus and extracoronary factors in the regulation of coronary blood flow. Coronary flow was measured from the bypassed right heart when the left ventricle pumped the entire systemic flow (method "A") and when a heart-lung machine generated systemic pressure (method "B"). In method "B," the mechanical activity and the oxygen consumption of the heart could be dissociated from systemic pres sure by the use of a balloon in the ventricle. Control measurements were performed in "uninjured" hearts; when a balloon was inflated to a left ventricular diastolic pressure of 15 mm. Hg or more, a state of "cardiac injury" supervened.
The arterial oxygen content was kept above 20 to 21 vol. per cent, but the cardiac oxygen consumption varied over a wide range. Whenever hemodynamic factors changed, coronary flow was a highly correlated, straight-line function of the difference between the aortic pressure and the left ventricular pressure, which we call the "coronary driving pressure." In "injured" hearts this linearity and high correlation persisted, but the slope of the regression line increased. We conclude that coronary flow is determined by the integrated difference between the propulsive force (the fluctuating pressure head at the coronary ostia) and opposing forces (intramyocardial pressure, which is known to oppose local coronary flow whenever and wherever it exceeds intravascular pressures). Cardiac oxygen consumption and coronary blood flow were not significantly related and were, therefore, coordinated by purely mechanical pressure differentials and not by changes of coronary vasomotor tonus. However, coronary vasomotor tonus decreased markedly during arterial anoxia or after various types of cardiac injury; it increased after Pitressin.
Factors Which Initiate or Influence Edema in the Isolated Dog's Heart
Authors: SALISBURY PETER F. , CROSS CECIL E. , KATSUHARA KIMIKO , RIEBEN P. ANDRE 
Published: June 2012

Isolated dog hearts were perfused while time heart weight was electrically recorded. Arterialized blood was pumped into a coronary perfusion reservoir either from the femoral artery of a donor dog or from the arterial outlet of various oxygenators. The right heart was widely open. The presence of myocardial edema and the rate of fluid accumulation in heart muscle were observed from the slopes of tile weight registration and from the difference of the directly measured heart weights before and after an experiment. Blood hold-up was measured in three experiments with tagged red cells: it accounted for 15 per cent or less of the observed weight gain.
When the heart was perfused from a donor dog and was not otherwise injured, myocardial edema fluid did not accumulate unless the coronary pressure exceeded 200 mm. Hg. Myocardial edema also formed when blood was diluted with Ringer's solution or after cardiac injury; the rate of edema formation was then dependent on the coronary perfusion pressure. Edematous hearts could often be made to lose weight (i.e., edema fluid) when perfused at pressures below 100 mm.Hg. Perfusion with blood from a disposable bag oxygenator initiated inyocardial edema formation almost immediately.
Cardioglobulin
Authors: LEONARD EDWARD , HAJDU STEPHEN 
Published: June 2012

The plasma concentration of cardioglobulin C has been compared in hypertension, aortic stenosis, aortic insufficiency, and in a group of normal subjects. The concentration in subjects with aortic insufficiency was normal; whereas in the groups with aortic stenosis and with hypertension, the concentration was significantly increased. These findings suggest that there may be some relationship between the increased plasma concentration of cardio-globulin C and the development of increased left ventricular isometric tension in systole, which is characteristic of patients with aortic stenosis or essential hypertension.
Cardioglobulin C concentration was measured in a group of patients with congestive heart failure secondary to valvular disease, and in two groups of patients with cardiac failure secondary to myocardial disease, either of known or of unknown cause. The results showed that the cardioglobulin C concentration in congestive failure secondary to valvular disease or to muscle disease of known cause was not significantly different from normal. The 17 patients with congestive failure secondary to muscle disease of unknown cause could be divided into two populations with respect to cardioglobulin C concentration. One group had concentrations which fell in the normal range, whereas the other group had extremely low values. The findings are discussed in relation to the hypothesis that the cardioglobulin system may be essential for maintaining normal myocardial contractility in warm-blooded animals.
Measurement of Mitral Regurgitation by IndicatorDilution Tecirniques
Authors: LEVISON WILLIAM H. , JACKSON WILLIAM D. , SHERMAN HERBERT , MCGUIIRE LOCKHART B. 
Published: June 2012

ethocls f o r q u a n t i f y i n g initral regurgitation that require the measurenlent only of tlie area enclosecl by the inclicator-clilution curves offer the advantage of being computationally simpler tha11 the others. Furthermore, clistortions in the shape of t h e curve will not necessarily induce significant error in the area enclosecl by the curve. Since such methocls require sampling from t h e a t r i u m as well as from the ventricle, or proximal aorta, the?- will lw successful only if meaningful samples uf indicator concentration can he obtained from these chambers.
The cluestion remains to be arc$\\-erecl: 13 the mixing in the cardiac chambers sufficient to allow meaningful sampling in both atrium and rentricle? A review of the literature on this, subject 11s been inconclusive."-" MTe iwe not aware of any experiments in which all of the conclitions aftecting cardiac chamber mising have been controllecl without seriously disturbing normal carcliac physiology. Such ;in experiment shoulcl control the nature of injection (i.e., one or mauy successi\-e pulses). the number ancl placement of the orifices a t the tip of the injection catheter, ancl the timing of the i u j e c t i o ~ l with the carcliac cycle.
Experiments indicate t h a t the optim~um mixing conclitions exist at the beginning of ventricular filling ancl that injection should be timed to coincide with this point in tlw cycle. I t is of interest to note that, in the clye curve e x p e r i m e ~ ~ t s by Sinclair et al.Ix in whic.11 animals were used, t h e time a t which injcctions were macle was found to be unimportant. 'I'his important difference between t11c mising characteristics of the mechanical ~noclcl and an animal lieart illustrates the cliificulties cncountered in the application of moclel results ancl observations to the human heart. It seems reasonable to conjecture, ho\vever, that the \\,ell-estal~lisl~ecl mixing properties of flows through valves ancl orifiws in ripicl systems will be enhancecl in the cleformable wall situation encountered in the h r a r t . F u r t h e r experiments using the indicator-dilution technique on both normal ancl abnormal hearts are evidently requirecl t o determine the nature ancl extent of tlie clepenclence of measurement reliability on the sanipling site location.
Outflow Resistance as an Independent Determinant of Cardiac Performance
Authors: IMPERIAL ELIAS S. , LEVY MATTHEW N. , ZIESKE HARRISON 
Published: June 2012

In the modified heart-lung preparation of the dog, sudden increases in outflow resistance were imposed during the diastolic interval between two beats. The changes in cardiac performance which were recorded during the first beat at higher resistance represent the response to augmented resistance per se, since there was no change in the initial length or initial tension of the ventricular myocardial fibers. Increased resistance elicited an immediate elevation of the peak aortic systolic pressure. This pressure rise was a direct function of the magnitude of the outflow resistance, and the effect was enhanced at higher left atrial pressures. Peak aortic flow and stroke volume were inversely related to the magnitude of the outflow resistance. At slight to moderate increases of resistance, stroke work was relatively unaffected; with more severe augmentations of resistance, however, stroke work varied inversely with outflow resistance. Arterial compliance played an important role in the ventricular response. For any given increase of resistance, the reductions of peak aortic flow and ventricular power were more severe when the arterial system was more rigid.
It is concluded that the limits of cardiac performance are determined by the initial conditions, such as fiber length or tension, previous activity, temperature, and nervous and humoral factors. Within these limits, however, ventricular performance is determined by the afterload, of which the outflow impedance is an integral component.
Action of Ryanodine on Mammalian Cardiac Muscle
Authors: HAJDU STEPHEN , LEONARD EDWARD 
Published: June 2012

The relationship between stimulation frequency and twitch tension was determined for isolated strips of rat right ventricle. Prolonged perfusion of the tissue in physiological saline solution results in diminished twitch tension at low rates of stimulation without alteration of contractility at high stimulation frequency. These changes, which develop over a period of several hours of perfusion, can be induced within 15 minutes by the addition of ryanodine. The addition of strophanthidin restores the twitch tension-frequency relationship of the long-perfused rat ventricle to normal. However strophanthidin has no effect on the impaired contractility of ryanodine treated ventricle ; and, conversely, the addition of ryanodine to digitalized ventricle abolishes the action of the glycoside. The effects of ryanodine can be reversed by perfusing the muscle in a solution which is deficient in either sodium or potassium.
Because of the opposing actions of ryano-dine and the cardiac glycosides, the effect of ryanodine was studied in anesthetized animals with digitoxin-induced cardiac arrhythmias. The intravenous infusion of ryanodine rapidly abolishes the ventricular arrhythmias characteristic of digitalis toxicity. However, the presence of both digitoxin and ryanodine is frequently associated with depression of sinus node activity, and the cardiac cycle is initiated by another focus, probably nodal. The effect on the sinus node may be mediated by the vagus, through a synergistic action of the two drugs, since normal sinus rhythm can be restored by the administration of atropine.
Public attitudes towards the acceptability of using drugs to treat depression and ADHD
Authors: Partridge Brad , Lucke Jayne , Hall Wayne 
Published: June 2012

Objective: This paper examines public attitudes towards the acceptability of using prescription drugs to treat depression and attention deficit hyperactivity disorder (ADHD), and whether attitudes are influenced by familiarity with the use of pharmacological treatments for these disorders. Method: Participants were 1265 members of the general public aged 18–101 years (50% female) participating in the Queensland Social Survey (QSS), an omnibus state-wide survey of households in the state of Queensland. The survey was administered through a CATI (computer-assisted telephone interviewing) system. Results: Most members of the public thought that the drug treatment of depression was acceptable (55%) but attitudes were much less positive towards the use of drugs to treat ADHD (35.6% acceptable). Regression analyses showed that respondents who knew someone who had received pharmacological treatment for depression were more likely to find it acceptable. However, participants were divided about the acceptability of drug treatment for ADHD regardless of whether they knew someone who had received drug treatment for ADHD or not. Participants with a higher level of education were more likely to find drug treatment for depression and ADHD acceptable. Participants who did not know anyone who had received drug treatment were less likely to have a definite opinion on whether it was acceptable or unacceptable. Conclusions: Attitudes towards the acceptability of the use of prescription drugs are more positive for depression than for ADHD. This may broadly reflect ongoing controversies in the public sphere about the potential over-diagnosis of ADHD or overmedication of children with ADHD. Members of the public who do not know anyone with depression or ADHD may need particular information from prescribers in the event that they (or their child) are diagnosed.
A historical overview of Korean public administration: discipline, education, association, international cooperation and beyond indigenization
Authors: Kim Pan Suk 
Published: June 2012

Modern public administration was introduced in Korea more than half a century ago. Over the past several decades, Korea has achieved substantial economic growth as well as the significant development of a public administration system. How, and in what way, has Korean public administration as a discipline grown rapidly? This article reviews the multiple dimensions of Korean public administration: the development of public administration as a new discipline, public administration education as a new channel of management knowledge, the development of professional associations and research institutes as a promoter of research and activities, and international cooperation as a development tool and a window of opportunity. After that, prospects based on an indigenization debate and concluding remarks will follow. Points for practitioners Public administration played a significant role in the development of South Korea. Korean public administration programs during the developmental process fostered a new class of civil servants and public management of the government. However, post-war Korean public administration has faced a problem of indigenization as it becomes more influenced by the Western world while attempting to hold on to traditional Confucian values. Thus, Korea needs to cope with such challenges creatively as it moves forward independently from its past.