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R Zahn

Publications and source records attributed to R Zahn.

At least 109 records · Page 6Linked to original sources
PubMed1997

[Tricuspid valve endocarditis. Demonstration of a rare disease exemplified with 3 case reports].

BACKGROUND: Endocarditis of the tricuspid valve is a rare form of valvular endocarditis and occurs mainly in patients with special risk factors. CASE REPORTS: The three case reports demonstrate 3 young patients (age 30 to 37 years, 2 female and 1 male) with a typical history of those risk factors. The two women were intravenous drug addicts and one of them had suffered already an episode of tricuspid valve endocarditis several years ago. The man developed his infection after implantation of a pacemaker. In all of the three patients the endocarditis was due to infection with staphylococci twice staphylococcus epidermidis and once staphylococcus aureus. In two of the three patients the endocarditis could not be cured by intravenous antibiotics alone and these patients had to undergo cardiac valvular surgery. All patients left the hospital after several weeks without signs of infection. CONCLUSION: In clinical praxis the introduction of a special endocarditis service, a small team which has to be consulted in every suspected case of endocarditis, seems to be beneficial as well as the use of the Duke criteria for diagnosis in those cases.

AIDS-Related Opportunistic Infections↗
PubMed1997

A structural model for GroEL-polypeptide recognition.

A monomeric peptide fragment of GroEL, consisting of residues 191-376, is a mini-chaperone with a functional chaperoning activity. We have solved the crystal structure at 1.7 A resolution of GroEL(191-376) with a 17-residue N-terminal tag. The N-terminal tag of one molecule binds in the active site of a neighboring molecule in the crystal. This appears to mimic the binding of a peptide substrate molecule. Seven substrate residues are bound in a relatively extended conformation. Interactions between the substrate and the active site are predominantly hydrophobic, but there are also four hydrogen bonds between the main chain of the substrate and side chains of the active site. Although the preferred conformation of a bound substrate is essentially extended, the flexibility of the active site may allow it to accommodate the binding of exposed hydrophobic surfaces in general, such as molten globule-type structures. GroEL can therefore help unfold proteins by binding to a hydrophobic region and exert a binding pressure toward the fully unfolded state, thus acting as an "unfoldase." The structure of the mini-chaperone is very similar to that of residues 191-376 in intact GroEL, so we can build it into GroEL and reconstruct how a peptide can bind to the tetradecamer. A ring of connected binding sites is noted that can explain many aspects of substrate binding and activity.

Chaperonin 60↗
PubMed1997

Refolding chromatography with immobilized mini-chaperones.

Mini-chaperones (e.g., a peptide consisting of residues 191-345 of GroEL) that are immobilized on agarose have very efficient chaperoning activity with several proteins that are otherwise recalcitrant to renaturation by conventional methods. We have used immobilized mini-chaperones both in column chromatography and batchwise to renature an insoluble protein from an inclusion body, to refold apparently irreversibly denatured proteins, and to recondition enzymes that have lost activity on storage. Refolding chromatography offers an efficient and simple means to renature proteins in high yield and with biological activity.

Chaperonin 60↗
PubMed1997

Primary angioplasty versus thrombolysis in the treatment of acute myocardial infarction. ALKK Study Group.

This study investigates the hypothesis if primary angioplasty is superior to intravenous thrombolysis in the treatment of acute myocardial infarction (AMI). Small prospective randomized studies did not demonstrate a significant benefit regarding total mortality. A total of 14,980 patients with AMI were registered by "The 60-Minutes Myocardial Infarction Project," a prospective multicenter observational study: 210 of these patients were treated with primary angioplasty. A matched pair analysis comparing 1 primary angioplasty patient with 3 intravenous thrombolysis patients could be performed in 156 primary angioplasty patients. Criteria for matching were age, sex, location of AMI, systolic blood pressure, previous AMI, and prehospital delay. Patients with a bundle branch block or requiring resuscitation were excluded from analysis. Because of matching, both groups showed similar baseline characteristics. Patients with primary angioplasty had more relative contraindications for thrombolysis (ulcers: 10.3% vs 2.3%, recent intramuscular injections: 6.4% vs 1.6%, recent surgical interventions: 5.1% vs 1.1%, central punctures: 9% vs 3.9%). There was a tendency toward less combined adverse events in the primary angioplasty group (3.2% vs 5.7%, odds ratio [OR] = 0.55, 95% confidence interval [CI] = 0.21 to 1.44). In-hospital mortality rates in the primary angioplasty group and thrombolysis group were 4.3% and 10.3%, respectively (OR = 0.39, 95% CI = 0.17 to 0.92). The difference in mortality could already be demonstrated within the first 48 hours with 1.9% versus 5.3% deaths (OR = 0.35, 95% CI = 0.11 to 1.14). Thus this study indicates a superiority of primary angioplasty in comparison to intravenous thrombolysis in AMI even in a clinical routine setting, with a reduction of hospital mortality of about 60%.

Aged↗
PubMed1997

Pseudoaneurysm after cardiac catheterization: therapeutic interventions and their sequelae: experience in 86 patients.

After diagnostic cardiac catheterization in 8,715 patients, a pseudoaneurysm was diagnosed in 86 (1%) patients. Primary conservative management by repeated compression bandages (CB) or ultrasound guided compression (UGC) was attempted in all patients. Occlusion of the pseudoaneurysm was achieved significantly more often by UGC (41/47; 87%) than by CB (22/39; 56%; P = 0.016). Of 86 patients, 23 (27%) required surgical treatment. Major clinical acute complications occurred after surgery in 8/23 cases (35%) versus 4/63 (6%; P = 0.0004) following successful CB or UGC. However, intention-to-treat analysis showed no difference in the rate of acute complications in the CB or UGC group (15.4% versus 12.8%, P = 0.7272), because of a trend towards a higher complication rate following secondary surgery in the UGC (4/6 = 66.7%), as compared to the CB group (4/17 = 23.5%, P = 0.1589). During follow up, 22/64 (34%) patients reported persistent inguinal complaints, 9/15 (60%) after surgery and 13/49 (27%) after successful CB or UGC (P = 0.0169). However, according to the intention-to-treat analysis, there was no significant difference between the initial groups (CB: 26.1% versus UGC: 39.0%, P = 0.2958). Despite a higher effectiveness of UGC to achieve occlusion of a pseudoaneurysm compared to CB (87% vs. 56%), UGC is not superior to CB because of a higher rate of acute complications as well as long-term complaints in those patients requiring secondary surgery in the UCG group as compared to the CB group.

Adult↗
PubMed1997

[Direct dilatation and emergency bypass operation of main branch occlusion in acute anterior wall infarct and cardiogenic shock].

Occlusion of the left main coronary artery (LMCA) is the cause of myocardial infarction in about 0.04%. Those patients who do not die during the acute phase often do have a dominant right coronary artery with extensive collaterals to the left coronary artery. Because this is a very rare situation there are only some cases reports dealing with the management of these patients. A 60 years old woman was admitted to our hospital with the signs of an acute Q-wave anterior myocardial infarction. Within a few minutes after the arrival she developed a cardiogenic shock. Coronary angiography was performed immediately. The left main coronary artery was occluded and a big right coronary artery showed a significant stenosis. There were many collaterals from the right coronary artery supplying the left coronary artery. After information of the cardiac surgeons, primary angioplasty of the LMCA was performed in order to achieve hemodynamic stabilisation and to relieve symptoms. Reperfusion of the left anterior descendent coronary artery (LAD) could be achieved within 30 minutes. This led to hemodynamic stabilisation of the patient. But a significant residual stenosis of the LMCA remained and the circumflex artery was still occluded. In the meanwhile cardiac surgery was able to be performed and so the patient was transferred to surgery without further dilatation or stent implantation. Four venous grafts (LAD, first diagonal branch, circumflex artery and right coronary artery) were inserted. After 4 weeks the patient was in a good shape and could be discharged at home. Primary angioplasty seems to be an effective treatment in patients with acute myocardial infarction and an occlusion of the LMCA. But coronary bypass surgery is nearly almost necessary during the following period in order to achieve complete revascularisation and to improve survival.

Angioplasty, Balloon, Coronary↗
PubMed1997

[Problems in carrying out baroreflex sensitivity measurements in clinical routine practice: practicability and complications].

Measurement of baroreflex sensitivity is a new method to identify patients after myocardial infarction with a high risk for sudden cardiac death, ventricular tachycardia or ventricular fibrillation. In this retrospective study the baroreflex sensitivity was obtained noninvasively by measuring the systolic blood pressure blood pressure with a FINAPRES-device and correlating this with the R-R intervals of the ECG after raising blood pressure with an intravenous dose of Norfenefrin-hydrochloride (Novadral). According to other investigators a correlation of > 0.7 with a significance of p < 0.05 was recommended for evaluable results with a baroreflex sensitivity < 3 ms/mm Hg being judged as decreased. We investigated 302 patients (mean age 59 +/- 17 years, 224 males, 78 females). 75% of the investigations showed acceptable results. In 77 cases (25%) reasonable results could not be achieved. We found premature ventricular beats to be responsible in 18 investigations (6% of all investigations). 41 (13.1%) of all investigations were not evaluable because of bad correlation for unknown reason. When we looked closely at these nonevaluable results, we found a significantly higher number of patients with impaired left ventricular ejection fraction (< 40%), diabetes or inducible sustained ventricular tachyarrhythmia in the electrophysiologic study in this group. During all investigations no severe side effects were observed. We conclude that the noninvasive measuring of the baroreflex sensitivity is a save method and leads to reasonable results in 75% of the investigations. In 13.1% it is not possible for unknown reason to achieve sufficiently correlating values. These measurements cannot be evaluated from nowadays' standards and have to be further investigated as they may indicate a population at high risk.

Adult↗
PubMed1997

[High frequency catheter ablation as therapy of symptomatic ventricular extrasystole].

Ventricular ectopic activity is commonly encountered in clinical practice. Usually it is not associated with life-threatening consequences in the absence of significant structural heart disease. However, frequent ventricular ectopic beats can be highly symptomatic and even incapacitating in some patients. Currently, reassurance and pharmacological therapy are the mainstays of treatment. This study assesses the useful role of catheter ablation in eliminating drug refractory monomorphic ventricular ectopic beats in severely symptomatic patients. Eight patients were included, five patients had no heart disease and in three patients a structural heart disease was present (coronary artery disease in 1, hypertensive heart disease in 1, mitral valve prolaps in 1). The ejection fraction was higher than 40% in all patients (mean EF 56 +/- 14%). Mean number of ventricular ectopic activity was 29,295 +/- 10,650 VPB/24 h (1209 +/- 457 VPB/h) before ablation. No other spontaneous or induced arrhythmias were documented. The site of origin of ventricular ectopic activity was accurately mapped by using earliest endocardial activation time during ectopic activity or pace mapping, or both. The ectopic focus was located in the right ventricular outflow tract in five patients and in the left ventricle in three patients (posteroseptal 2, anterolateral 1). Frequent ventricular ectopic beats were successfully eliminated by catheter ablation in all patients. Early recurrence occurred in one patient after 10 min and 30 min after the procedure. In another patient a recurrence occurred 6 days after the procedure. In a second session he was successfully ablated and remained free of recurrence since 2 months. After ablation the mean number of ventricular premature beats was 211 +/- 159 VPB/24 h (9 +/- 7 VPB/h). The mean number of radiofrequency applications was 8 +/- 7 (range 2-22). Mean radiation time was 12 +/- 8 min. No complications were observed. During a mean follow-up of 6 months there were no further recurrences in the remaining six patients. Radiofrequency catheter ablation can be successfully used to eliminate monomorphic ventricular ectopic activity. It may therefore be a reasonable alternative for the treatment of severely symptomatic, drug resistant monomorphic ventricular ectopic activity.

Adult↗
PubMed1997

[Early treatment of acute myocardial infarct: implementation of therapy guidelines in routine clinical practice, MITRA pilot phase].

The prognostic value of thrombolytics, aspirin, beta-blockers and ACE-inhibitors has been well documented in large clinical trials, but the application of these drugs in clinical practice is not known. MITRA is a multicenter study of 54 hospitals in a defined region in southwest Germany. The aim is to document actual clinical practice (pilot phase) and to establish an individually optimised prognostic therapy for acute myocardial infarction, considering only the absolute contraindications for each drug. In the pilot phase, 1303 consecutive patients with acute transmural myocardial infarction were enrolled. The median age was 66 years, the prehospital time was 2.7 hours. 47% had an anterior infarction. In the subgroup of patients without absolute contraindications, only 53.4% were treated with thrombolytics, 87.6% with aspirin, 37.1% with beta-blocker, and 17.4% with ACE-inhibitor. Out of these, patients were classified as "optimally treated" if they received thrombolysis, aspirin as well as beta-blocker. Patients were also included if any of these medications was withheld in the presence of absolute contraindications. Treatment was defined suboptimal, if the patients did not receive any of these three medications despite the absence of absolute contraindications. Only 29% (n = 383) received an optimal post-infarction therapy and 71% (n = 775) a suboptimal treatment. The univariate analysis revealed 10 variables influencing optimal therapy. In this subgroup patients were younger, they more often had clear ECG-findings or left bundle branch block, an anterior infarction, acute cardiac failure, AV-block, bradycardia, recent trauma or surgery (less then 2 weeks) and a severe chronic obstructive lung disease. The prehospital time was more often available. Early mortality after 2 days was 5.0% versus 9.3% in the suboptimal treated patients (OR: 0.5, CI: 0.30-0.86) the total inhospital mortality was 10.9% in the optimal versus 17.7% in the suboptimal group (OR: 0.6, CI: 0.38-0.84). In a multivariate analysis the parameter "optimal treatment" was found to be an independent predictor of the early (OR = 0.4; CI: 0.20-0.69) and the inhospital mortality (OR = 0.4; CI: 0.25-0.64). The following in-hospital events occurred: stroke 2.8%, reinfarction 12.9%, cardiac failure 21.5%, cardiogenic shock 10.4% and in-hospital mortality 18.1% (2-days mortality 9.5%). Pharmacological therapy for acute myocardial infarction is inconsistent with the recommendations suggested in recent clinical trials and needs to be individually optimised. Optimal treatment is an independent predictor of early and inhospital mortality.

Adrenergic beta-Antagonists↗
PubMed1997

[Balloon dilatation in acute myocardial infarct in routine clinical practice: results of the register of the Working Society of Leading Cardiologic Hospital Physicians in 4,625 patients].

Balloon angioplasty as the treatment of first choice in the setting of an acute myocardial infarction (AMI) is gaining widespread acceptance because of favourable results from specialised centres concerning high patency rates and low mortality. This study reports the results of angioplasty for AMI at large community hospitals during 1992-1995. 4625 procedures were performed at 68 centres of the Arbeitsgemeinschaft Leitender Kardiologischer Krankenhausärzte (ALKK). The age of the patients was 60.8 +/- 11.3 years, with 75.1% men. The infarct related artery was the left anterior descendent in 43%, the right coronary artery in 37%, the circumflex artery in 16%, a bypass graft in 2.3% and the left main stem in 1.4% of patients. The success rate (residual stenosis < 50%) of the intervention was 86%. There was a wide range of procedures per centre, with a median of 40 AMI angioplasties per year and centre. The amount of angioplasties for AMI in relation to all angioplasties performed during this period rose from 5.2% in 1992 to 5.9% in 1995 (p = 0.01). Local complications at the puncture site occurred in 3.2%, with the need for a surgical intervention in 1.1% of patients. In 273 (5.9%) of the patients a second angioplasty was performed during the hospital stay. Aortocoronary bypass surgery was performed in 3% of the patients. Hospital mortality was 9.5% (438/4625 patients). The mortality rate remained constant during the years investigated (1992: 10.6%; 1993: 8.6%; 1994: 9.7%; 1995: 9.8%; p = ns). Higher mortality was observed in older patients, patients with multiple vessel disease, the left anterior descending artery or a bypass graft as infarct related artery as well as in patients with failed reperfusion (residual stenoses > 50%). Hospitals with a case load of more than 40 angioplasties for AMI per year showed a lower mortality as compared to the others. In clinical practice at large community hospitals results of angioplasty for AMI concerning mortality, complications and technical success rate are comparable to those of highly specialised centres. The absolute numbers of angioplasties for AMI increased constantly over the years.

Aged↗
PubMed1997

[Clinical safety using the thrombocyte aggregation inhibitor c7E3 in interventional cardiology in 520 patients].

The monoclonal antibody c7E3 (ReoPro) is a highly selective inhibitor of platelet aggregation that binds to the fibrinogen receptor (GP IIb/IIIa) on the surface of platelets and leads to a dose-dependent, nearly complete inhibition of platelet aggregation. The clinical value of c7E3 to reduce ischemic events after PTCA in addition to heparin and aspirin has been demonstrated in the EPIC-, EPILOG-, and CAPTURE-trial. In these studies, c7E3 was associated with an increased bleeding risk after the coronary intervention. The DTREO-Trial (German trial with c7E3) was designed as a prospective study to investigate the clinical safety of c7E3 in the daily routine of a cath lab. From April 1995 through September 1996 520 patients were enrolled at 30 German sites. c7E3 was mainly used in patients with acute coronary syndromes (55% unstable angina Braunwald Class I-III and C; 28% in acute myocardial infarction) and in patients with complex coronary lesions (AHA/ACC classification type B and C lesion in 84% of the study group). In 51% of the interventions a stent was implanted (25% in bailout-situations and in 26% as an elective intervention) and c7E3 was used as an adjunctive to prevent sub-acute stent thrombosis. The incidence of "major" bleeding events (TIMI-classification) was less frequent in this study as in the EPIC-trial and comparable to the results of the EPILOG- and CAPTURE trial. In conclusion this study confirms the positive risk profile of c7E3 in patients undergoing high-risk percutaneous revascularization procedures.

Abciximab↗
PubMed1997

Local venous thrombosis after cardiac catheterization.

Pulmonary embolism is a rare but life-threatening complication of cardiac catheterization. Underlying deep venous thrombosis (DVT) is often not detectable clinically. To determine the true incidence of DVT the authors prospectively studied 450 consecutive patients (29% women, 71% men, mean age: fifty-eight years) undergoing a diagnostic cardiac catheterization. Patients were examined clinically and by duplex sonography with a high-resolution (5 or 7.5 MHz) transducer before and twenty-four hours after catheterization before mobilization. Duplex sonography excluded complete proximal DVT in all patients. Only partial occluding thrombi (pDVT) were detected in 11 (2.4%) patients. The thrombi were always localized at the puncture site. In 2 patients a difference was found in the circumferences of the legs, but no other clinical signs of DVT were seen. With use of continuous wave (cw) Doppler sonography, only 3 of these 11 patients (27%) showed a spontaneous (s) sound. Phlebography was performed in 4/11 patients (36%). In 2 patients the diagnosis was confirmed; in 1 patient extravenous compression was assumed, and the other demonstrated a normal-appearing phlebography at the time of investigation. Logistic regression analysis yielded a 3.5 times higher risk for developing a pDVT if a venous puncture was performed in addition to arterial puncture. Furthermore a 9.8 times higher risk was found if more than one venous puncture was necessary. During the follow-up no patient developed clinical signs of pulmonary embolism. The results of this study demonstrate that DVT is a rare complication of cardiac catheterization (0/450 patients), but pDVT occurred in 2.4%. Risk factors for pDVT are the venous puncture itself and multiple puncture attempts. Clinical relevance of pDVT remains to be determined.

Cardiac Catheterization↗
PubMed1997

Overview of clinical trials with glycoprotein IIb-IIIa receptor antagonists in the prevention and management of coronary.

Platelet aggregation is mediated by the glycoprotein IIb-IIIa receptor, a member of the integrin superfamily of membrane-bound adhesion molecules. In the activated platelet, binding to the major adhesive proteins, fibrinogen and von Willebrand, occurs due to a conformational change of the glycoprotein IIb-IIIa receptor. Glycoprotein IIb-IIIa receptor antagonists effectively block the binding of these adhesive proteins and thus inhibit platelet aggregation. Large-scale clinical trials have demonstrated the benefits of these agents in patients undergoing percutaneous coronary angioplasty and with acute coronary syndromes compared to conventional antiplatelet therapy. Furthermore, trials are in progress in patients with acute myocardial infarction. The beneficial effects of these agents was first demonstrated with abciximab, a monoclonal antibody to the glycoprotein IIb-IIIa receptor, in patients at risk of coronary arterial thrombosis, and was further illustrated in trials with other IIb-IIIa receptor blocking agents, both with synthetic peptide and non-peptide receptor antagonists. This review focuses on the glycoprotein IIb-IIIa receptor antagonists most advanced in clinical development.

Journal Article↗
PubMed1996

Chaperone activity and structure of monomeric polypeptide binding domains of GroEL.

The chaperonin GroEL is a large complex composed of 14 identical 57-kDa subunits that requires ATP and GroES for some of its activities. We find that a monomeric polypeptide corresponding to residues 191 to 345 has the activity of the tetradecamer both in facilitating the refolding of rhodanese and cyclophilin A in the absence of ATP and in catalyzing the unfolding of native barnase. Its crystal structure, solved at 2.5 A resolution, shows a well-ordered domain with the same fold as in intact GroEL. We have thus isolated the active site of the complex allosteric molecular chaperone, which functions as a "minichaperone." This has mechanistic implications: the presence of a central cavity in the GroEL complex is not essential for those representative activities in vitro, and neither are the allosteric properties. The function of the allosteric behavior on the binding of GroES and ATP must be to regulate the affinity of the protein for its various substrates in vivo, where the cavity may also be required for special functions.

Allosteric Regulation↗
PubMed1996

Postinfarction stress testing and one year outcome of stable patients after myocardial infarction treated with thrombolytics.

OBJECTIVE: The purpose of our study was to evaluate the predictive power of early postinfarction stress testing in survivors of uncomplicated MI treated with thrombolytics. METHODS: The study population consisted of 102 consecutive, thrombolyzed survivors (56 +/- 11 years) of acute, transmural myocardial infarction with uncomplicated postinfarction course. All patients were clinically stable in the postinfarction period and underwent cycle ergometry, 99mTc perfusion scintigraphy and dobutamine stress-echocardiography within three weeks after the acute event. Coronary angiography was used to determine the extent of CAD, LV ejection fraction (LVEF), TIMI grade and residual stenosis of the infarct-related coronary artery. A follow up questionnaire was performed one year after hospital discharge to determine the relation to the occurrence of cardiac events (unstable angina, reinfarction, PTCA, bypass surgery and death). RESULTS: 30 patients developed 34 cardiac events. Four patients died. Two thirds of the 'cardiac events' in the year of follow-up were revascularization procedures mostly selected by evidence of ischemia on 99mTc perfusion scintigraphy and/or stress-echocardiography. These two methods were significantly associated with the development of new cardiac events (stress-echocardiography: p < 0.01; 99mTc perfusion scintigraphy: p < 0.006). Parameters of bicycle ergometry and variables of coronary angiography were not related to an increased risk of future cardiac events. The number of 'hard cardiac events'--death or nonfatal AMI--was too small (8%) in these patients who are able to exercise to make statistical comparisons. CONCLUSIONS: The study underlines the necessity of early noninvasive risk assessment to identify patients at a greater risk among survivors of uncomplicated AMI treated with thrombolytics who are clinically stable in the early postinfarction period. PTCA and coronary bypass surgery is performed in one third of these patients selected mostly by evidence of ischemia on 99mTc perfusion scintigraphy and/or stress-echocardiography. Results of bicycle ergometry are of limited value in these patients within the first year after acute myocardial infarction.

Coronary Angiography↗
PubMed1996

Conformational states bound by the molecular chaperones GroEL and secB: a hidden unfolding (annealing) activity.

We have analysed the conformational states of barnase that are bound by the molecular chaperones GroEL and SecB. Line broadening in the NMR spectra of barnase in the presence of chaperone indicates binding of the native state of barnase to both GroEL and SecB, with a dissociation constant of > 3 x 10(-4) M for the GroEL-native barnase complex. GroEL and SecB catalyse the hydrogen-deuterium exchange of amide proteins of barnase that require global unfolding for exchange to occur, indicating that both chaperones bind to a fully unfolded state of barnase. Binding of the denatured state was also detected by a reversible lowering of the melting temperature of barnase in the presence of chaperone. The dissociation constant of the complex between denatured barnase and either chaperone is 5 x 10(-8) M. The chaperone-bound fully unfolded state is a minor conformation that would not be seen by direct observation under physiological conditions, as the folding intermediate of barnase is the most populated state in the complex. The rate-limiting step for exchange of buried amide protons of bound barnase is the unfolding of the folding intermediate, which is retarded > 2000-fold in the complex with GroEL. The reverse refolding step is retarded > 1000-fold by GroEL leading to an EX1 mechanism for exchange. In contrast, unfolding of native barnase is catalysed by > 1000-fold. Thus, molecular chaperones GroEL and SecB have the potential to act in vivo and in vitro as: (1) a folding/transport-scaffold to prevent aggregation of partially folded states by binding; (2) as an annealing-machine to generate continuous unfolding of misfolded states until a low-affinity state is formed; and (3) as an unfoldase to catalyse unfolding of the misfolded states.

Amides↗
PubMed1996

Intraindividual comparison of three stress tests during the early postinfarction period in stable patients with thrombolysis.

The intention of the study was to intraindividually compare the ischemic yield of three stress tests early after acute myocardial infarction. At a large community hospital 107 stable patients who survived acute transmural myocardial infarction after thrombolytic therapy followed by an individual optimized medical treatment, were prospectively investigated by three noninvasive stress tests. All patients received bicycle ergometry, 99mTc perfusion scintigraphy and stress-echocardiography within three weeks after the acute event. Each patient underwent diagnostic cardiac catheterization for determination of angiographic data. 99mTc perfusion scintigraphy had the highest rate of positive test results (61%), as compared to bicycle ergometry (32%), stress echocardiography (34%) and stress induced angina in any of the stress tests performed (40%). In 79% of the patients studied, at least one of four ischemic parameters was positive. The combination of bicycle ergometry, stress induced angina and 99mTc perfusion scintigraphy detected myocardial ischemia in 78% of the patients studied. Concordance of at least three positive parameters was seen in only 27%. Intraindividual comparison between positive and negative test results was inconclusive. Only stress-echocardiography versus stress-induced angina showed a moderate agreement (kappa = 0.44). Stress-induced angina was the only ischemic parameter which corresponded to the grade of the residual stenosis of the infarct related coronary artery (p < 0.01) and reduced left ventricular function (p < 0.005). These findings show, that concordance of three common stress tests in detecting myocardial ischemia anywhere in patients after acute transmural myocardial infarction and thrombolytic therapy is poor. Stress-echocardiography and stress inducible angina show a moderate agreement. Follow-up studies of these patients are currently performed to clarify prognostic significance and therapeutic consequences of positive test results in these patients.

Angina Pectoris↗