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T Walther

Publications and source records attributed to T Walther.

At least 55 records · Page 3Linked to original sources
PubMed2001

Dual natriuretic peptide response to volume load in the fetal circulation.

OBJECTIVE: To measure atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in control fetuses and fetuses with Rhesus isoimmunisation before and after intravascular transfusion. The current study was designed to investigate the response of ANP and BNP to cardiac short-term and long-term volume load in the human fetus. METHODS: Fetal blood samples were collected from 18 human fetuses (nine controls, nine anemic fetuses with Rhesus isoimmunisation before and after intravascular transfusion). Fetal ANP and BNP concentrations were measured and compared to maternal plasma levels. RESULTS: Both ANP and BNP were significantly higher in fetal blood compared to the mothers. Fetuses with Rhesus isoimmunisation, characterized by long-term cardiac overload, showed significantly elevated ANP but not BNP concentration compared to the fetal controls (ANP: 80.8+/-16.6 vs. 31.6+/-7.7 pg/ml, P<0.05). However, short-term volume load due to intravascular transfusion leads to a significant increase in the fetal BNP- but not ANP-plasma level (BNP: 112.9+/-14.1 vs. 64.8+/-6.6 pg/ml, P<0.05). CONCLUSION: ANP and BNP respond differently to cardiac short- and long-term volume load in the fetal circulation. Therefore, the data suggest that in the fetus, similar to adults, ANP and BNP constitute a dual natriuretic peptide system responsive to changes in cardiac filling pressure.

Analysis of Variance↗
PubMed2001

The influence of aeration and hemicellulosic sugars on xylitol production by Candida tropicalis.

The influence of other hemicellulosic sugars (arabinose, galactose, mannose and glucose), oxygen limitation, and initial xylose concentration on the fermentation of xylose to xylitol was investigated using experimental design methodology. Oxygen limitation and initial xylose concentration had considerable influences on xylitol production by Canadida tropicalis ATCC 96745. Under semiaerobic conditions, the maximum xylitol yield was 0.62 g/g substrate, while under aerobic conditions, the maximum volumetric productivity was 0.90 g/l h. In the presence of glucose, xylose utilization was strongly repressed and sequential sugar utilization was observed. Ethanol produced from the glucose caused 50% reduction in xylitol yield when its concentration exceeded 30 g/l. When complex synthetic hemicellulosic sugars were fermented, glucose was initially consumed followed by a simultaneous uptake of the other sugars. The maximum xylitol yield (0.84 g/g) and volumetric productivity (0.49 g/l h) were obtained for substrates containing high arabinose and low glucose and mannose contents.

Aerobiosis↗
PubMed2001

Transmyocardial laser revascularization with the holmium:YAG laser: loss of symptomatic improvement after 2 years.

OBJECTIVE: Whether transmyocardial laser revascularization (TMLR) provides a long-term benefit in terms of relief of angina, improvement of exercise tolerance, left ventricular function, and myocardial perfusion. METHODS: Forty-one patients underwent TMLR using a holmium:YAG-laser, 14 as TMLR alone (group A), 27 with additional aortocoronary bypass grafting (group B). Follow-up was obtained at 6, 12, 18, 24, and 36 months in this prospective study. RESULTS: In group A patients CCS-class improved up to 18 months postoperatively, after 24 and 36 months postoperatively there was absence of a positive effect of TMLR: the CCS-class decreased to 2.4 as compared to 3.5 preoperatively After combined CABG and TMLR (group B) there was a significant decrease in angina at all times. The CCS-functional class in these patients was 1.7 at 36 months as compared to 3.5 preoperatively. There was no significant change in exercise tolerance as compared to preoperatively. Left ventricular ejection fraction did not improve in either of the groups. Thallium scintigraphy indicated no improvement in myocardial perfusion in laser treated areas. The perioperative mortality was 0%, the late mortality rate was 36% in group A and 11% in group B. CONCLUSIONS: In our experience, in the vast majority of patients who are subjected to TMLR alone the benefit of reduction or relief of angina and improvement in quality of life is only temporary. In addition there is no improvement in objective clinical parameters. We believe that TMLR should only be used in patients with severe angina refractory to medical treatment and requiring a symptomatic therapy.

Aged↗
PubMed2001

Computer-enhanced "robotic" cardiac surgery: experience in 148 patients.

OBJECTIVE: A computer-enhanced instrumentation system was used in 148 patients to minimize access in cardiac surgical procedures. METHODS: The da Vinci telemanipulation system (Intuitive Surgical, Mountain View, Calif) provides a high-resolution 3-dimensional videoscopic image and allows remote, tremor-free, and scaled control of endoscopic surgical instruments with 6 degrees of freedom. By April 2000, the system had been used in 131 patients for coronary artery bypass grafting and 17 patients for mitral valve repair. In the coronary bypass group, the system was used in one of three ways: (1) to take down the internal thoracic artery followed by a minimally invasive direct coronary bypass procedure (n = 81); (2) to perform the anastomosis between the internal thoracic artery and the left anterior descending coronary artery in standard-sternotomy coronary bypass (n = 15); or (3) for total endoscopic coronary artery bypass grafting to anastomose the left internal thoracic artery to the left anterior descending on the arrested heart (n = 27) or the beating heart (n = 8). In 17 patients with nonischemic mitral valve insufficiency the mitral valve was repaired. Closed-chest cardiopulmonary bypass with cardioplegic arrest (Port-Access technique; Heartport, Inc, Redwood City, Calif) was used for arrested-heart total endoscopic coronary bypass and mitral valve repair. RESULTS: The da Vinci system allows for precise tissue handling and enables the endoscopic performance of cardiac surgical tasks that require a high degree of dexterity (coronary anastomosis, mitral valve repair). No technical mishaps have occurred. The internal thoracic artery was successfully taken down in 79 of 81 patients in the group undergoing minimally invasive coronary bypass and, after a steep learning curve, is currently performed in less than 40 minutes. The postoperative patency rate is 96.3%. Total endoscopic coronary bypass was completed in 22 of 27 cases with 95.4% patency as demonstrated by angiography at 3 months' follow-up. Closed-chest endoscopic beating-heart bypass grafting was successfully performed in 2 out of 8 patients with the use of a new endoscopic stabilizer. In the group having mitral valve repair, primary endoscopic computer-enhanced repair was successfully completed in 14 of 17 patients; three others had to be changed to a standard endoscopic technique, including 1 who required valve replacement. At 3 months' follow-up, 1 additional patient underwent early reoperation for recurrent mitral insufficiency. Overall early and late mortality in this cohort of 148 patients was 2.0% and was not related to the use of the system. CONCLUSION: In conclusion, computer-enhanced endoscopic cardiac surgery can be performed safely in selected patients. Internal thoracic artery takedown is now routinely performed with good results. Total endoscopic coronary bypass is feasible on the arrested heart but does not offer a major benefit over the minimally invasive direct approach because cardiopulmonary bypass is still required. The early clinical experience with closed-chest beating-heart bypass grafting outlines the limitations of this approach despite some procedural success.

Animals↗
PubMed2001

Left ventricular function in mice lacking the AT2 receptor.

OBJECTIVES: The role of the AT2 receptor in the heart is incompletely understood. We investigated left ventricular performance in AT2 receptor knockout mice, with and without deoxycorticosterone acetate (DOCA)-salt treatment. Given the putative opposing functions of the AT1 and AT2 receptor, we also analysed AT1 receptor expression in the left ventricle. METHODS: We used a miniaturized conductance-manometer system to measure pressure-volume loops for analysing left ventricular performance under baseline conditions and after increasing peripheral vascular resistance. We determined left ventricular AT1-receptor expression by RNase-protection assays. RESULTS: In AT2 receptor knockout mice, end-systolic and end-diastolic volumes were lower than in wild-type mice, so that pressure-volume loops were shifted leftward. Left ventricular systolic and diastolic kinetics were not different between the groups. AT2 receptor knockout mice and wild-type mice both stabilized their reduced stroke volume after laparatomy as peripheral resistance was increased. DOCA-salt treatment increased elastance in AT2 receptor knockout mice, compared to controls. Furthermore, AT2 receptor knockout mice had a steeper increase in dP/dtmax. Left ventricular AT1 receptor gene expression was increased in AT2 receptor knockout mice and was not down-regulated in response to DOCA-salt treatment. Finally, the hearts of AT2 receptor knockout mice were smaller than controls, but increased in size in response to DOCA-salt treatment. CONCLUSIONS: AT2 receptor knockout mice displayed no major changes in left ventricular function at baseline or in response to DOCA-salt treatment, compared to wild-type mice. The AT2 receptor may be important to AT1 receptor expression in response to DOCA-salt challenge and may have some influence on cardiac growth responses.

Animals↗
PubMed2001

Baroreflex improvement in shr after ace inhibition involves angiotensin-(1-7).

ACE inhibitors are extensively used in the treatment of hypertension mainly because of their efficiency in reducing blood pressure levels and decreasing vascular and cardiac hypertrophy. In addition, ACE inhibitors improve baroreceptor reflex control. Chronic inhibition of ACE produces (in addition to decreased angiotensin II levels) a severe increase in angiotensin-(1-7) [Ang-(1-7)] levels in several species. We have previously shown that Ang-(1-7) produces a facilitation of the baroreflex control of heart rate. In this study, we evaluated the participation of endogenous Ang-(1-7) in the improvement of baroreflex sensitivity in spontaneously hypertensive rats after central infusion of ramiprilat, an ACE inhibitor. Reflex changes in heart rate were elicited, in conscious rats, by bolus injections of phenylephrine (baroreflex bradycardia) before and after intracerebroventricular infusion of (1) saline (8 microL/h), 4 hours (n=5); (2) ramiprilat (14 microg/h), 4 hours (n=6); (3) ramiprilat for 2 hours, followed by ramiprilat combined with A-779 (4 microg/h), a selective Ang-(1-7) antagonist, for an additional 2 hours (n=6); and (4) A-779 for 2 hours, followed by A-779 combined with ramiprilat for an additional 2 hours (n=5). Intracerebroventricular infusion of ramiprilat produced an important increase ( approximately 40%) in baroreflex sensitivity (evaluated as the ratio between changes in heart rate and changes in mean arterial pressure) that was completely reversed by A-779. Furthermore, intracerebroventricular infusion of A-779 prevented the improvement of the baroreflex sensitivity produced by ramiprilat. Intracerebroventricular infusion of saline or A-779 alone did not significantly alter the baroreflex sensitivity. These results suggest that endogenous Ang-(1-7) is involved in the improvement of baroreflex sensitivity observed in spontaneously hypertensive rats during central ACE inhibition.

Analysis of Variance↗
PubMed2000

Organ-specific mRNA distribution of C-type natriuretic peptide in neonatal and adult mice.

C-type natriuretic peptide (CNP) is described as an endothelium-derived vasodilator and a growth inhibitor of vascular smooth muscle cells. In the present study, CNP mRNA was quantified by RNase-protection assay to elucidate organ distribution of CNP in neonatal and adult mice. In adult mice, the highest CNP expressions were detected in uterus and ovary, which exceeded the CNP concentrations of forebrain and brainstem. In contrast, neonatal mice showed highest CNP-mRNA levels in forebrain and brainstem with lower levels in skin, tongue, heart, lung, thymus, skeletal muscle, liver, kidney, stomach, and skull. Thus, CNP-expression pattern diminishes during postnatal development. The observation that the expression level of CNP mRNA is 2.2-fold higher in the adult forebrain compared to the neonatal forebrain allows a comparison between all neonatal and adult organs.

Aging↗
PubMed2000

Prospectively randomized comparison of different mechanical aortic valves.

BACKGROUND: The aim of this prospectively randomized study was to evaluate the hemodynamic and functional outcomes after aortic valve replacement with 3 different bileaflet mechanical valves. METHODS AND RESULTS: Three hundred consecutive patients were randomly assigned to receive ATS (n=100), Carbomedics (n=100), or St Jude Medical Hemodynamic Plus (n=100) mechanical aortic valve replacement. There were no significant differences regarding patient age (average 61+/-8 years), body surface area (1.9+/-0.2 m(2)), left ventricular function (ejection fraction 0.59+/-0.17), and presence of aortic stenosis (90%, 89%, and 91%), respectively. All patients had postoperative as well as 6-month and 1-year follow-ups that included transthoracic echocardiography. Multivariate statistical analysis was performed. Implanted valve sizes were comparable at 24+/-2 (ATS), 23.7+/-1.6 (CM), and 23.6+/-1.9 (SJMHP) mm (NS). At 1-year follow-up, the following incidence of events was noted: death 3/1/1, all non-valve related; stroke 0/1/1; trivial transvalvular incompetence 3/3/2; paravalvular leak 2/3/2; and reoperation 0/1/1, respectively (NS). Transvalvular flow velocities were 2.5/2.6/2.4 m/s postoperatively (P:=0.03) and 2.4/2.4/2.3 m/s at 6-month follow-up, respectively (NS). There was a significant decrease in left ventricular mass for all patients but no significant differences among the groups. CONCLUSIONS: There are no clinically relevant differences among the tested bileaflet aortic valves. Regardless of valve type, there was a low complication rate. On the basis of these findings, all 3 bileaflet prostheses are well suited for aortic valve replacement.

Aortic Valve↗
PubMed2000

Humoral immune response during coronary artery bypass grafting: A comparison of limited approach, "off-pump" technique, and conventional cardiopulmonary bypass.

BACKGROUND: The introduction of limited approaches to the heart and the avoidance of cardiopulmonary bypass (CPB) aim to reduce the invasiveness of CABG by decreasing the systemic release of inflammatory cytokines, such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8, as well as the anti-inflammatory agent IL-10. This study compares the humoral immune response in patients undergoing CABG with standard, minimally invasive, and "off-pump" techniques. METHODS AND RESULTS: Thirty patients were divided into 3 operative groups: full sternotomy approach plus CPB (group A); full sternotomy approach, off pump (group B); and limited left anterior thoracotomy, off pump (group C). Plasma levels of TNF-alpha receptors p55 and p75, IL 6, IL-8, and IL-10 were taken at baseline, during CPB, and at 4, 24, and 48 hours and 6 days after surgery. A significant increased release of activated complement factors C5a and C3d, IL-8, and IL-10 was observed in patients subjected to CPB (group A) during the initial period and for a short time after perfusion (P:<0.05). TNF-alpha receptors p55 and p75 showed a prolonged elevation (up to 48 hours) in the CPB group compared with the 2 off-pump groups. IL-6 showed no different release among the 3 surgical groups throughout the entire period. There was no significant difference in any parameter measured in relation to the type of operative approach. CONCLUSIONS: There is an inflammatory, as well as an anti-inflammatory, response during CABG that is related to the general surgical trauma. The release of immune mediators is enhanced by the use of CPB during various perioperative and postoperative phases. The type of operative approach did not influence this immune response.

Aged↗
PubMed2000

Hypoalgesia and altered inflammatory responses in mice lacking kinin B1 receptors.

Kinins are important mediators in cardiovascular homeostasis, inflammation, and nociception. Two kinin receptors have been described, B1 and B2. The B2 receptor is constitutively expressed, and its targeted disruption leads to salt-sensitive hypertension and altered nociception. The B1 receptor is a heptahelical receptor distinct from the B2 receptor in that it is highly inducible by inflammatory mediators such as bacterial lipopolysaccharide and interleukins. To clarify its physiological function, we have generated mice with a targeted deletion of the gene for the B1 receptor. B1 receptor-deficient animals are healthy, fertile, and normotensive. In these mice, bacterial lipopolysaccharide-induced hypotension is blunted, and there is a reduced accumulation of polymorphonuclear leukocytes in inflamed tissue. Moreover, under normal noninflamed conditions, they are analgesic in behavioral tests of chemical and thermal nociception. Using whole-cell patch-clamp recordings, we show that the B1 receptor was not necessary for regulating the noxious heat sensitivity of isolated nociceptors. However, by using an in vitro preparation, we could show that functional B1 receptors are present in the spinal cord, and their activation can facilitate a nociceptive reflex. Furthermore, in B1 receptor-deficient mice, we observed a reduction in the activity-dependent facilitation (wind-up) of a nociceptive spinal reflex. Thus, the kinin B1 receptor plays an essential physiological role in the initiation of inflammatory responses and the modulation of spinal cord plasticity that underlies the central component of pain. The B1 receptor therefore represents a useful pharmacological target especially for the treatment of inflammatory disorders and pain.

Animals↗
PubMed2000

Pain is significantly reduced by cryoablation therapy in patients with lateral minithoracotomy.

BACKGROUND: In minimally invasive cardiac surgery use of a lateral minithoracotomy is associated with early postoperative rehabilitation but also relatively high pain levels during the first 3 postoperative days. Cryoablation therapy was evaluated prospectively. METHODS: From April 1999 until September 1999, 57 patients underwent lateral minithoracotomy for mitral valve operation (n = 18) or minimally invasive direct coronary artery bypass grafting (n = 39). Intraoperatively, patients were randomly assigned to cryoablation or intercostal application of local anesthetic agents. A standardized questionnaire was used for prospective pain assessment on postoperative days 1 to 7. RESULTS: From postoperative day 1 to 7 pain levels declined in all groups. Overall pain levels were significantly lower in the cryo group than in the control group (p < 0.0001, GLM). According to diagnoses, pain levels were significantly lower after MIDCABG and cryo versus control; after mitral valve operation they were lower in the cryo group and almost reached significance. CONCLUSIONS: Cryoablation is easy to perform and leads to a significant reduction in pain and lower request for additional pain medication after lateral minithoracotomy in minimally invasive cardiac operation.

Anesthetics, Local↗
PubMed2000

Cerebral microemboli during minimally invasive and conventional mitral valve operations.

BACKGROUND: Intraoperative cerebral microembolism may cause postoperative neurologic damage. The aim of this study was to determine the frequency of cerebral microembolic signals (MES) during minimally invasive surgery (MIS) and conventional (conv.) mitral valve operations and to determine the association of MES with various stages of the operation. METHODS: Intraoperative computer-aided transcranial Doppler measurements were performed to detect cerebral microemboli in 21 patients undergoing MIS and in 14 patients undergoing conv. mitral valve operation. We calculated the mean embolic rate for three time periods: P1, start of the operation until aortic clamping; P2, aortic clamping until clamp removal; and P3, declamping until end of surgery. RESULTS: There was no significant difference in the total number of detected cerebral MES between both patient groups (MIS 1,014+/-753, conv. 937+/-519; NS). In both groups, the highest number of MES were detected during the third time period when the heart regained effective ejection (MIS 875+/-746, conv. 680+/-462; p > 0.5). CONCLUSIONS: Transcranial Doppler was useful to detect cerebral microemboli in MIS and conv. mitral valve operation. We found no increased risk of cerebral microembolism during the minimally invasive method compared with the conventional technique.

Cardiopulmonary Bypass↗
PubMed2000

Combined stentless mitral valve implantation and radiofrequency ablation.

BACKGROUND: The aim of this study was to evaluate the results of combined stentless mitral valve (SMV) replacement and intraoperative radiofrequency ablation for chronic atrial fibrillation (IRAAF) to restore physiologic hemodynamic function. METHODS: Since July 1998 12 patients (72+/-4 years, 10 women, mitral stenosis/mitral incompetence 8/4, NYHA 3.3+/-0.4, CI 1.8+/-0.5) had SMV implantation and received additional IRAAF by inducing continuous left atrial lesion lines from the MV annulus to all four pulmonary veins and to the atriotomy. RESULTS: The flexible SMV was implanted at the papillary muscles and at the annulus using a conventional (n = 6) or a minimally invasive approach (n = 6). Sinus rhythm was successfully restored in 10 of 12 patients with 6- and 12-months' follow-up; 2 required DDD-pacemaker implantation. However, in the early postoperative period several interventions including medical treatment (sotalol or amiodarone) in 9 and electrical cardioversion in 7 patients was required. Two patients required reinterventions: 1 cardioversion and 1 amiodarone medication after 3 and 6 months, respectively. At echocardiography the SMV demonstrated good hemodynamic function and atrial contraction. CONCLUSIONS: Restoration of physiologic cardiac function by SMV implantation and IRAAF is advantageous and no further anticoagulation is required.

Aged↗
PubMed2000

Sex specific behavioural alterations in Mas-deficient mice.

Male mice lacking the Mas protooncogene have been shown to exhibit an increased anxiety in the Elevated Plus Maze Task and sustained long-term potentiation in the hippocampus without effect on spatial learning in the Morris Water Maze Task. Here, we report behavioural studies in female mice lacking the Mas protooncogene. As for the males, we analysed the learning and anxiety behaviour using both behavioural tasks. With the exception of a trend to a better performance in the Morris Water Maze no differences were found in both tests between control and Mas-deficient females. This implicates that the lack of Mas protein influences spatial learning and anxiety in a sex-specific manner.

Animals↗
PubMed2000

Baroreflex sensitivity, heart rate, and blood pressure variability in normal pregnancy.

Heart rate variability is a relevant predictor of cardiovascular risk in humans. However, to use heart and blood pressure (BP) variability or baroreflex sensitivity as markers for hypertensive pregnancy disorders, it is first necessary to describe these parameters in normal pregnancy. To accommodate the complexities of autonomic cardiovascular control we added parameter domains of nonlinear dynamics to conventional linear methods of time and frequency domains. The BP of 27 women with normal pregnancy and 14 nonpregnant women were monitored at a high resolution (200 Hz sampling frequency) using a Portapres for 30 min. The pregnant women were divided into groups of 32 or less or greater than 32 weeks of gestation. Pregnant and nonpregnant women were classified into subclasses of maternal age of less than 28 or 28 or more years. Except for two single parameter domains, we found no significant differences in heart rate and BP variability for pregnant women with different gestational age or different maternal age. Moreover, no significant differences in spontaneous baroreflex sensitivity could be found between pregnant women regardless of either their age or gestational age. In contrast, all measures of nonlinear dynamics of heart rate variability as well as all parameter domains of spontaneous baroreflex sensitivity showed significant changes between pregnant and nonpregnant women, whereas BP variability did not differ between those groups. This complex assessment of autonomic cardiovascular regulation has shown that the parameters tested are stable in the second half of normal pregnancy, and might have the potential to be excellent indicators of pathophysiologic conditions.

Adult↗
PubMed2000

Total endoscopic computer enhanced coronary artery bypass grafting.

OBJECTIVE: In an effort to minimize access in coronary artery bypass (CAB) surgery, a total endoscopic approach using computer enhanced technology was developed. METHODS: By July 1999 the da Vinci telemanipulation system (Intuitive Surgical, Mountain View, CA) was used in 66 patients with coronary artery disease. In 12 patients undergoing routine coronary artery bypass grafting (CABG) (group 1) the internal thoracic artery (ITA) to left anterior descending artery (LAD) anastomosis was performed remotely using the system. In 32 patients (group 2) endoscopic dissection of the ITA was performed followed by a conventional minimally invasive direct coronary artery bypass (MIDCAB) operation. In 22 patients (group 3) the complete operation was performed endoscopically through 4 ports (total endoscopic coronary artery bypass, TECAB). Port-Access cardiopulmonary bypass with cardioplegic arrest was used for TECAB. RESULTS: In group 1 the time for performing the ITA to LAD anastomosis was 17 +/- 10 min. Mean graft flow was 38 +/- 25 ml/min. One anastomosis leaked and was repaired manually. In group 2 in 31/32 patients (96%) the ITA harvest was successfully performed with the system at mean of 61 +/- 27 min. There was a substantial learning curve associated with ITA take-down. In one patient a dissection caused insufficient free ITA graft flow which necessated additional vein grafting. Postoperative angiography demonstrated graft patency in all cases. In the TECAB group, the operation could be completed through four ports in 18 of the 22 patients (82%) with operating times in the range 220-507 min. In four patients, elective conversion to a minithoracotomy was required due to failure to identify the LAD (1), bleeding from the anastomosis (1), grafting of a diagonal branch (1) and torsion of the pedicle (1). One patient required reoperation for bleeding from an ITA side-branch. Median intubation time was 13 h and stay on ICU and hospitalization were 20 h and 7 days, respectively. A 3-month follow-up angiography revealed patent grafts in all TECAB patients. CONCLUSION: Endoscopic ITA harvesting and performing of arterial anastomoses can be safely performed with the da Vinci system. TECAB is possible on the arrested heart with good functional results. However, a substantial learning curve has to be overcome which is reflected in long operation times and an initial significant conversion rate.

Cardiopulmonary Bypass↗
PubMed2000

Upregulation of bradykinin B1-receptor expression after myocardial infarction.

To determine the influence of the myocardial infarction (MI) on bradykinin B1-receptor (B1R) regulation, we studied its expression in the left ventricle (LV) after MI. Rats were submitted to a permanent occlusion of the left coronary artery. Six hours, 24 h and 6 days after MI or after sham operation, left ventricular pressure (LVP) and dP/dt(max) were measured. LV-total RNA was extracted and B1R expression was analysed by a RNase-protection assay (each group n = 6). LVP and dP/dt(max) were impaired at all time points after MI. Basal B1R expression was not detectable in controls. Six hours after MI, the B1R expression was upregulated and reached a maximum 24 h after MI (4 fold vs. 6 h). Six days post-MI, B1R expression returned to levels found 6 h after MI. These data are the first demonstration for an induced myocardial B1R expression in an in vivo model of MI.

Animals↗