Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.11.18 (MAP)
 7,412 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In 17 normal subjects we studied the changes evoked by five levels of expiratory pressure (EP) ranging from 2.5 to 30 mmHg in a number of circulatory variables during the last 10 s of a 30-s Valsalva maneuver. Variables studied included mean arterial (MAP) and pulse (PP) pressures; right atrial (RAP) and peripheral vein (PVP) pressures; cardiac output (CO); total peripheral resistance (TPR) and heart rate (HR). EP-circulatory response curves were obtained in each subject a) before autonomic block; b) after cardiac effector block (atropine + propranolol); c) after "total" autonomic block (atropine + propranolol; guanethidine + phentolamine). Mechanical effects were determined from results during "total" autonomic block. They included EP-related rises in RAP and PVP each to about 0.7 mmHg/mmHg applied EP, and falls in CO, MAP, and PP to levels of approximately 50%, 70%, and 80% of resting respectively at EP 30 mmHg, but no changes in TPR and HR. Reflex effects included EP-related rises in HR and in TPR and in MAP, to levels of 160%, 160%, and 115% of resting respectively at EP 30 mmHg. The afferent input profile is probably complex, and the role of the different receptor groups may vary at the different levels of EP.
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PMID:Reflex and mechanical circulatory effects of graded Valsalva maneuvers in normal man. 93 59

Hypertension is a common phenomenon in patients undergoing aortocoronary bypass grafting. This hypertension increases myocardial oxygen consumption and can be prevented by application of vasodilators. A possible cause is activation of the renin angiotensin system. Magnesium is a potent vasodilator and has a beneficial effect after myocardial ischaemia. The study was performed to analyse the influence of magnesium infusion on the haemodynamic status and plasma renin activity in patients undergoing aortocoronary bypass grafting. METHODS. Eighteen patients (NYHA classification II-III) undergoing bypass surgery were divided into two groups, a magnesium and a control group. The magnesium group (n = 9) received 0.8 mEq/kg per h magnesium aspartate as an infusion for 15 min while still awake. After induction of anaesthesia, the magnesium infusion was reduced to 0.2 mEq/kg per h and stopped after aortic cannulation was completed. Plasma magnesium levels and concentrations within erythrocytes were measured. Anaesthesia was induced by flunitrazepam (0.01 mg/kg), fentanyl (0.005 mg/kg) and pancuronium (0.1 mg/kg). After intubation, patients were normoventilated with N2O/O2 = 1:1 and isoflurane (0.5-1.0 vol%). Additional doses of fentanyl (0.0025 mg/kg) were injected before the incision and before sternotomy. Mean arterial pressure, heart rate, cardiac index, total peripheral resistance, pulmonary vascular resistance, mean pulmonary arterial pressure, pulmonary capillary wedge pressure, left ventricular stroke work index, right ventricular stroke work index, intrapulmonary shunt and plasma renin activity were evaluated at five predefined points: (1) prior to magnesium infusion; (2) after magnesium infusion; (3) 10 min following induction of anaesthesia under steady-state conditions; (4) after sternotomy; (5) after aortic cannulation. RESULTS. Concerning the haemodynamic parameters (MAP, RAP, PAP, PCWP) no significant difference between the two groups could be demonstrated. In the control group peripheral resistance (TPR) was higher following sternotomy and aortic cannulation than in the magnesium group. Magnesium prevented decrease of the cardiac index (CI) under steady-state conditions, during sternotomy and following aortic cannulation. Left and right ventricular stroke work indexes (LVSWI and RVSWI) were higher in the magnesium group. Plasma renin levels were not significantly different between the two groups. CONCLUSION. Patients undergoing cardiac surgery benefit from magnesium administration in the pre-bypass phase. Due to its vasodilating effect, magnesium lowers the output impedance of the left ventricle and improves cardiac pumping function. It opposes detrimental cardiovascular responses to sternotomy and following aortic cannulation. Also of importance is the advantageous effect of magnesium on cardiac arrest elicited by cardioplegia and for reactivation of the ischaemic myocardium.
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PMID:[Hemodynamics of coronary surgery patients following magnesium aspartate infusion]. 148 73

Complex interrelationships exist between the right (RV) and the left ventricles (LV). Therefore, in 30 consecutive patients with reduced LV function (left ventricular ejection fraction [LVEF]) less than 40% undergoing myocardial revascularization, RV hemodynamics were studied from the beginning of anesthesia until the end of the operation. The data were compared with 30 consecutive patients with normal LVEF (greater than 70%). Ventricular function was assessed during left heart catheterization, which was carried out within 1 month of the operation. In addition to standard hemodynamic variables, RV ejection fraction (RVEF), RV end-diastolic volume (RVEDV), and RV end-systolic volume (RVESV) were monitored by the thermodilution technique. The two groups did not differ preoperatively with regard to RVEF, pressure (MAP, PAP, PCWP, RAP, RVPsyst, RVEDP), cardiac index (CI), and volume variables (RVESV, RVEDV). However, when the group with preoperatively reduced LVEF was subdivided into patients with severely reduced LVEF (less than 30%; n = 14; mean value 25.1%) and patients with moderately reduced LVEF (30%-40%; n = 16; mean value 37.3%), RVEF was significantly lower in the patients with a LVEF below 30% throughout the entire investigation period. RVEDV and RVESV were significantly higher in these patients. In conjunction with the lower RVEF and normal PAP, this suggests reduced RV function. It can be concluded that a severely reduced preoperative LVEF (less than 30%) may also be associated with impaired RV function.
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PMID:Right ventricular function in patients with reduced left ventricular function undergoing myocardial revascularization. 154 48

The aim of this study was to assess the minimum time interval necessary to avoid the development of tolerance during nitroglycerin patch application. We studied 24 patients, aged 23 to 73 years, with ischemic or idiopathic dilated cardiomyopathy (LV EF less than 0.40) and stable clinical conditions during 30 days before the study. All patients had significant reduction of systemic and pulmonary arterial pressure after sublingual nitroglycerin. After the hemodynamic assessment of the response to the first dose of the nitroglycerin patch, the patients were randomized to 1 of 3 chronic treatment groups: continuous patch application (Group A), intermittent application with 4 hours intervals (Group B), intermittent application with 6 hours intervals (Group C). All patients were studied by right heart Swan-Ganz catheterization; the hemodynamic response to a 10 mg multilayer matrix nitroglycerin patch was assessed before and every hour, in the next 4 hours, after both the first application of the patch and after 1 month of therapy; after chronic intermittent therapy, hemodynamic parameters were also measured 24 hours after drug withdrawal. Hemodynamic parameters were significantly changed after the first nitroglycerin patch application: particularly, mean systemic arterial (MAP), right atrial (RAP) and pulmonary wedge pressures (PWP) declined from 96 +/- 10, 8.9 +/- 1.8 and 20.1 +/- 5 to 81 +/- 6, 4.7 +/- 1.5 and 12.2 +/- 3 mmHg (-15.6, -47.2 and -59.3%, respectively); systemic vascular resistance (SVR) and heart rate (HR) were reduced from 1645 +/- 121 to 1288 +/- 89 dyne.s.cm-5 and from 85 +/- 7 to 81 +/- 7 b/min; lastly, cardiac index (CI), stroke volume (SVI) and stroke work index (SWI) increased from 2.3 +/- 0.3, 28.2 +/- 5 and 28.7 +/- 9 to 2.7 +/- 0.3 l/min/m2, 33.3 +/- 5 ml/min/m2 and 31.5 +/- 8 g.m/m2 (+17.4, 18.1 and 9.7%). After 1 month of either continuous or intermittent patch application with 4 hours intervals, hemodynamic parameters returned to control values with no significant change after patch application. In contrast, after intermittent patch application with 6 hours intervals, a persistent hemodynamic response to nitroglycerin patches was still present.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[The acute, chronic continuous after treatment and chronic intermittent with a variable therapeutic window (4 and 6 hours) hemodynamic effects induced with transdermal nitroglycerin in patients with congestive heart failure]. 176 29

In addition to positive inotropic and atrioventricular conduction-blocking properties, digoxin is capable of producing systemic and pulmonary vasoconstriction. However, whether chronic digoxin treatment exacerbates the pulmonary hypertension that results from left atrial (LA) outflow obstruction has not been specifically examined. This study assessed the vascular and inotropic responses to 5 days of digoxin treatment in six conscious dogs before and after filling a permanently implanted LA balloon. Dogs were also instrumented to measure left ventricular (LV) pressure, LV dP/dt, mean systemic arterial (MAP), right atrial (RAP), pulmonary arterial, and pulmonary capillary wedge pressures, as well as cardiac output (CO). Under normal conditions with the balloon empty, digoxin treatment (40 micrograms/kg loading dose and 12 micrograms/kg/d for 5 days) reduced CO (-17%) and increased systemic (SVR) and pulmonary (PVR) vascular resistances 27% and 37%, respectively; heart rate (HR) and LV dP/dt were not changed. Filling the balloon with enough saline to double PVR also increased SVR (52%), HR (42%), and RAP (92%), and reduced CO (-24%). During LA outflow obstruction, 5 days of digoxin reduced HR (-17%), SVR (-29%), and RAP (-23%), but did not alter PVR, CO, or LV dP/dt. This study demonstrates that although systemic and pulmonary vasoconstriction result from chronic digoxin treatment under normal conditions, the drug produces systemic vasodilation and no change in PVR during LA outflow obstruction.
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PMID:The cardiovascular response to digoxin in conscious dogs with left atrial obstruction. 213 97

In distant heart procurement, optimal storage conditions remain to be defined, especially with respect to the electrolytic concentrations of storage solutions. Between December 1986 and April 1987, heart transplants were carried out in 18 patients. After cardioplegic arrest (St. Thomas), the hearts were randomly stored in either Euro-Collins' solution (ECS; n = 9) or Ringer's solution (RS; n = 9) at 4 degrees C. For the first 24 h postsurgery, atrial pressures (LAP, RAP), systemic (MAP) and pulmonary pressures (PAP), and cardiac output (CO) were monitored. In addition, catecholamine and nitroglycerin requirements as well as the type of cardiac rhythm were documented. There was no significant difference between the groups in terms of the period of graft ischemia (ECS, 162 +/- 28 min; RS, 141 +/- 47 min); the MAP, RAP, LAP, and CO were also similar in both groups. The total amount of epinephrine needed to maintain the MAP between 60 and 80 mm Hg was 10.5 mg/24 h +/- 4.1 mg in ECS compared with 19.9 mg/24 h +/- 12 mg in RS (P less than 0.05). Despite less inotropic support, the left cardiac work index was considerably higher in the ECS group (P less than 0.05). In the first few postoperative hours, 8/9 RS patients needed either atrial (n = 4) or ventricular pacing (n = 4) for a heart rate of 90-100 beats/min (bpm), whereas only three ECS patients required atrial pacing (P less than 0.05). All other ECS hearts showed a spontaneous sinus rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Distant heart procurement. Impacts of storage solution composition on cardiac performance following transplantation. 307 73

The present study was performed to compare hemodynamic effect of intravenous Nitroglycerin (TNT i.v.) in 14 patients developing acute hypertension (Group I) and in 7 non hypertensives after open heart surgery (Group II). In all patients, m.a. 56.6 yrs, (10 mitral and/or aortic prosthetic valve replacements, 9 aorto-coronary bypass, 1 open mitral commissurotomy, 1 closure of atrial septal defect) TNT was infused at doses of 0.5, 1, 2 microgram X kg X min. and subsequently at 2 microgram X kg X min. after volume administration (2 + V.A.) to maintain right and left atrial pressure the same as control (P = N.S.). Mean arterial, right and left atrial pressures (MAP, RAP, LAP), cardiac frequency and index (CF, CI and systemic vascular resistance index (SVRI) were monitorized. TNT i.v. resulted in hypertensive patients (Group I) in reduction vs. control of: a) RAP (--20.17%) and LAP (--20.58%) at 0.5 microgram X kg X min. b) RAP (--26.13%), LAP (--27.50%), MAP (--19.94%) and CI (--12.98%) at 1 microgram X kg X X min. c) RAP (--22.47%), LAP (--26.89%), MAP (--24.68%), CI (--12.6%) and SVRI (--17.34%) at 2 microgram X kg X min. When RAP and LAP was maintained by volume administration TNT i.v. (2 microgram X kg X min.) resulted in an even greater increase in CI and a greater decrease in MAP and SVRI ((--22.04% and --24.88% respectively). No significant hemodynamic modification (P less than or equal to 0.05) were observed in non hypertensive patients (Group II) at all doses of TNT i.v. The results confirm a predominant venodilator effect of TNT at low doses and a good effect on arterial resistances at high doses in hypertensive patients. In view of previous reports of differing effects on ischemia TNT i.v. may be preferable to other vasodilator drugs for control of acute post-ECG hypertension, only on condition to maintain an adequate left ventricular filling pressure to prevent a fall of cardiac index. Moreover the absence of significant (P less than or equal to 0.05) hemodynamic modifications in non hypertensive patients may be a further advantage in the treatment of myocardial ischemia with i.v. TNT.
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PMID:[Effect of intravenous nytroglicerin in hypertensive patients during and after open heart surgery (author's transl)]. 678 Apr 1

Continuous pump-driven veno-venous hemofiltration (CVVH) has become an established method for treatment of acute renal failure (ARF). Since severe disturbances of (micro-) circulation are intimately involved in the bad outcome of these patients, the profile of endocrinological regulators of circulation was prospectively and serially measured in patients undergoing pump-driven CVVH (n = 15). 15 patients with similar APACHE II score, but without ARF and without CVVH were also studied. Endothelin-1 (ET-1), atrial natriuretic peptide (ANP), vasopressin, renin, and catecholamine (epinephrine, norepinephrine) plasma levels were measured before start of CVVH (= "baseline") (in the non-CVVH patients: admission to intensive care unit) and during the next 5 days. Various hemodynamic parameters were additionally monitored. MAP, HR, PAP, CI, and right ventricular hemodynamics (RVEF, RVEDV, RVESV) remained almost unchanged in the CVVH patients and were without differences to the non-CVVH group within the entire investigation period. PCWP and RAP were higher in the CVVH patients already at baseline (RAP, 17.8 +/- 4.0 mmHg; PCWP, 22.1 +/- 4.5 mmHg) (p < .02) and remained elevated in the further course of the investigation. Renin plasma level was higher already at baseline in the CVVH patients (907 +/- 184 pg/ml) (p < .05) and further increased during CVVH (to 1453 +/- 186 pg/mL). Vasopressin increased only in the CVVH group (from 3.80 +/- .66 to 11.85 +/- 1.05 pg/mL) (p < .01).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Changes in regulators of circulation in patients undergoing continuous pump-driven veno-venous hemofiltration. 2597 10

1. The feedback control of arterial blood pressure by the kidney in the range of hours was investigated in resting, conscious foxhounds. 2. A servo-control device (connected to an aortic occlusive cuff implanted above both renal arteries) was used to maintain a constant pressure difference of 20 mmHg between aortic pressure measured proximal (mean arterial blood pressure: MAP) and distal (renal artery pressure: RAP) to the aortic cuff. 3. Protocol 1 (n = 6) served as a 4 h time control without intervention, protocol 2 (n = 6) consisted of three periods: after a control of 20 min duration, the servo-control device was activated for 180 min; this was followed by a recovery period of 40 min. Protocol 3 (n = 6) was as protocol 2, but during converting-enzyme inhibition. 4. Servo-control increased plasma renin activity (PRA) transiently from 0.5 ng angiotensin I (AI) ml-1 h-1 to a peak value of 2.4 ng AI ml-1 h-1, subsequently both RAP and MAP rose to reach a new steady state. During this increase in RAP, PRA declined to 1.4 ng AI ml-1 h-1. 5. On average, the compensation of the pressure decrease sensed by the kidney amounted to 63% of the error signal (closed-loop gain of 0.63 +/- 0.1). 6. Converting-enzyme inhibition reduced this closed-loop gain significantly (protocol 2 vs. protocol 3, 0.63 +/- 0.1 vs. 0.15 +/- 0.1; P < 0.05). 7. It is concluded, that the kidney plays an important role in medium-term blood pressure regulation, most probably via the renin-angiotensin system.
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PMID:The role of the kidney in canine blood pressure control: direct assessment of the closed-loop gain. 822 94

Bacteria and viruses may be transmitted through contaminated biological materials such as transplantable tumors, cell lines, sera or other biological material. Currently, the screening of biological material is being done using the mouse or rat antibody production (MAP/RAP) test (serological testing). We decided to test and validate an alternative assay using polymerase chain reaction (PCR / RT-PCR) technology to detect viral contamination directly in biological material. The aim of this study therefore is the validation of our new PCR assays and the comparison of PCR and MAP test. For 6/14 viruses the conventional PCR, seems to be more sensitive and more specific in detecting murine viruses. In 12/14 viruses the RT-PCR is more sensitive than MAP-test. In 2/14 cases all detection methods have the same sensitivity. Furthermore, PCR screening clearly contributes to the principles of 3R as a replacement technique as it eliminates the need for using animals to screen for murine viruses in biological material.
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PMID:[Replacement of mouse and rat antibody production test; comparison of sensitivity between the in vitro and in vivo methods]. 1209 34


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