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Biomedical subjects

P Urban

Publications and source records attributed to P Urban.

At least 19 recordsLinked to original sources
PubMed1999

[High-risk PTCA assisted by the Hemopump 14F: the Geneva experience].

INTRODUCTION: The hemopump is a transvalvular, catheter-mounted, left ventricular assist device, intended for surgical placement via the femoral artery (hemopump 21 Fr. outer diameter). This device has demonstrated its ability to unload the left ventricle, leading to myocardial protection and haemodynamic stabilisation in patients with cardiogenic shock and those undergoing high-risk coronary angioplasty (PTCA). Since 1994, a new hemopump system (14 Fr. in external diameter, flow rates of 1.5-2.2 l/min) has been developed for percutaneous insertion. The aim of this study is to describe the immediate and mid-term results obtained during Hemopump 14 Fr. assisted high-risk PTCA. PATIENTS: Between September, 1993 and July, 1996, 8 males and 5 female patients (mean age 68.5 +/- 8.6 years) underwent Hemopump 14 Fr. supported high-risk PTCA. RESULTS: Mean duration of hemopump assistance was 108 +/- 62 min. Hemopump support on maximum speed led to an increase of cardiac index from 2.0 +/- 0.3 to 2.2 +/- 0.5 l/min (p = 0.04) and a decrease of pulmonary wedge pressure from 17 +/- 8 to 14 +/- 8 mm Hg (p = 0.004). LDH increased (463 +/- 305 to 558 +/- 237 u/l-p = 0.05) and the platelet count remained stable (192,840 +/- 60,904 to 190,230 +/- 56,492/mm3). Successful balloon angioplasty was performed in all patients. There was no hospital mortality. Three patients (23%) required blood transfusion. During follow-up, 1 patient (7.7%) developed femoral artery occlusion necessitating surgical repair, and 3 patients (23%) died from cardiac causes 3, 9 and 14 months after the procedure. CONCLUSIONS: The 14 Fr. Hemopump device may constitute a useful percutaneous mode of haemodynamic support for patients undergoing high-risk PTCA. The haemolysis it causes is mild and not clinically significant, but the hemopump is associated with a significant rate of local vascular complications. Recent improvements in interventional techniques and hardware have decreased the necessity for circulatory assistance during elective PTCA, even for very ill patients. Nevertheless, indications such as cardiogenic shock, the "bridge" period prior to heart transplantation and video-assisted minimally invasive cardiac surgery, or haemodynamic support of the right ventricle are the new applications of the hemopump.

Aged↗
PubMed1999

[Treatment of acute myocardial infarction in Switzerland: is emergency PTCA more costly than thrombolysis?].

Confirming earlier studies with a lower number of patients, the Gusto IIb Angioplasty Substudy has shown that in the treatment of acute myocardial infarction emergency PTCA is superior to thrombolysis in reducing the combined clinical endpoints of death, reinfarction and cerebrovascular infarction. The aim of this study was to assess whether, in the Swiss study population of Gusto IIb, emergency PTCA was associated with higher procedural costs than thrombolysis over a median follow-up of 16 months. Therefore, we compared the costs of the initial and the follow-up hospitalisations. There were no differences in clinical characteristics in the Swiss subpopulation compared to the total study population. In a total of 46 patients, PTCA was performed in 22 and thrombolysis with rtPA in 24. During follow-up, 4 patients died, one in the PTCA group and 3 in the thrombolysis group (p = ns). The median total costs of the initial hospitalisation were somewhat higher in the PTCA group than in the group with thrombolysis. During follow-up only 38% of the patients in the PTCA group had to be rehospitalised, compared to 50% in the thrombolysis group. Median total costs within 16 months, therefore, were similar in the two therapeutic groups, but mean total costs per patient were somewhat lower for the PTCA versus the thrombolysis group (p = ns). Based on this comparison of Swiss procedural costs, emergency PTCA should not, in hospitals with the necessary infrastructure, be withheld in the treatment of acute myocardial infarction on the grounds of initially higher procedural costs, especially as the invasive strategy is associated with a more favourable long-term outcome.

Angioplasty, Balloon, Coronary↗
PubMed1999

Five-year outcome in patients with isolated proximal left anterior descending coronary artery stenosis treated by angioplasty or left internal mammary artery grafting. A prospective trial.

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass surgery (CABG) improve the clinical status of patients with isolated proximal left anterior descending coronary artery stenosis. At 2 years, only additional revascularization was more frequently required after PTCA. METHODS AND RESULTS: We monitored 134 patients randomized to PTCA (n=68) or CABG (n=66) for </=5 years. End points were death, myocardial infarction, need for additional revascularization, clinical status, and medical treatment. At 5 years, 6 patients (9%) had died in the PTCA group versus 2 (3%) in the CABG group (P=0.12). One patient in each group died of a cardiac cause. Myocardial infarction was more frequent after PTCA (15% versus 4%; P=0.0001), but Q-wave infarction was not (6% in the PTCA group versus 3% in the CABG group; P=0.8). Additional revascularization was required in 38% of patients in the PTCA group versus 9% in the CABG group (P=0.0001). Functional status was comparable, with 6% of patients after PTCA and 3% after CABG in functional class III or IV. Finally, after PTCA or CABG, 62% and 91% of patients, respectively, were free of events (P=0.0001). CONCLUSIONS: The 5-year prognosis of patients with isolated proximal left anterior descending coronary artery stenosis is good. Both PTCA and CABG improve clinical status, but revascularization was needed more frequently after PTCA. There is an excess incidence of non-Q-wave myocardial infarction in the PTCA group that does not affect the vital or symptomatic outcome.

Angioplasty, Balloon, Coronary↗
PubMed1999

Catalytic triad of microsomal epoxide hydrolase: replacement of Glu404 with Asp leads to a strongly increased turnover rate.

Microsomal epoxide hydrolase (mEH) belongs to the superfamily of alpha/beta-hydrolase fold enzymes. A catalytic triad in the active centre of the enzyme hydrolyses the substrate molecules in a two-step reaction via the intermediate formation of an enzyme-substrate ester. Here we show that the mEH catalytic triad is composed of Asp226, Glu404 and His431. Replacing either of these residues with non-functional amino acids results in a complete loss of activity of the enzyme recombinantly expressed in Saccharomyces cerevisiae. For Glu404 and His431 mutants, their structural integrity was demonstrated by their retained ability to form the substrate ester intermediate, indicating that the lack of enzymic activity is due to an indispensable function of either residue in the hydrolytic step of the enzymic reaction. The role of Asp226 as the catalytic nucleophile driving the formation of the ester intermediate was substantiated by the isolation of a peptide fraction carrying the 14C-labelled substrate after cleavage of the ester intermediate with cyanogen bromide. Sequence analysis revealed that one of the two peptides within this sample harboured Asp226. Surprisingly, the replacement of Glu404 with Asp greatly increased the Vmax of the enzyme with styrene 7,8-oxide (23-fold) and 9, 10-epoxystearic acid (39-fold). The increase in Vmax was paralleled by an increase in Km with both substrates, in line with a selective enhancement of the second, rate-limiting step of the enzymic reaction. Owing to its enhanced catalytic properties, the Glu404-->Asp mutant might represent a versatile tool for the enantioselective bio-organic synthesis of chiral fine chemicals. The question of why all native mEHs analysed so far have a Glu in place of the acidic charge relay residue is discussed.

Amino Acid Sequence↗
PubMed1999

Corrective use of the 2.5-mm GFX stent for suboptimal angioplasty results in small coronary arteries.

To evaluate the clinical efficacy of endoluminal stenting in the setting of percutaneous intervention for small coronary artery lesions, we reviewed our results on stenting with the 2.5-mm GFX stent (Arterial Vascular Engineering, Santa Rosa, CA) during an 18-month study period. A total of 120 patients with significant coronary artery disease in vessels </=2.6 mm were followed up clinically. Procedural success (defined as angiographic residual stenosis <20% without clinical complications) was obtained in 94% of cases. In-hospital complications were death (1%), non-Q-wave myocardial infarction (5%), and urgent repeat percutaneous intervention because of stent thrombosis (3%). During a mean follow-up of 9.8 months (range, 6-23 months), the following complications were noted: myocardial infarction (1%), clinical need for repeat intervention (13%) requiring repeat percutaneous treatment (12%) and surgical revascularization (1%). In conclusion, transcatheter application of a specifically designed stent for coronary artery disease in small vessels seems safe and efficient with a low incidence of adverse events during follow-up. Cathet. Cardiovasc. Intervent. 48:157-161, 1999.

Adult↗
PubMed1999

Neurological and electrophysiological examinations on three groups of workers with different levels of exposure to mercury vapors.

The authors performed neurological, visual evoked potentials (VEP) and electroneurography (ENG) examinations on three groups of workers with occupational exposure to mercury vapors (Hg(0)), and on a control group. The exposure of dental professionals (n = 36) was mild, that of chloralkali plant workers (n = 36) was intermediate, and that of workers from mercury works (n = 77) was very high. Symptoms and signs of micromercurialism were observed only in the group with the highest exposure to Hg(0). In comparison with the control group, a shortening of VEP latency and a decrease in amplitude were found in the exposed groups. The VEP changes correlated with Hg(0) excreted in urine after administration of a chelating agent - sodium 2,3-dimercapto-1-propan sulfonate (DMPS). The frequency of abnormal VEP results increased with increasing levels of exposure. ENG changes were observed only in the group with the highest exposure to Hg(0). An isolated decrease of sural nerve conduction velocity was observed in 18% of total workers. In 70% of the cases, this was associated with an abnormality in VEP. The combination of a decrease in sural nerve conduction velocity and an abnormality of VEP seems to be a characteristic pattern of electrophysiological changes in persons exposed to mercury vapors.

Adult↗
PubMed1999

A randomized evaluation of early revascularization to treat shock complicating acute myocardial infarction. The (Swiss) Multicenter Trial of Angioplasty for Shock-(S)MASH.

AIM: To test whether emergency revascularization improves survival in patients with acute myocardial infarction and shock. METHODS AND RESULTS: Patients with acute myocardial infarction and early shock were randomized either to undergo emergency angiography, followed immediately by revascularization when indicated, or to receive initial medical management. In five of the nine participating centres, patients with shock but not randomized were entered in a registry. Only 55 patients could be randomized. Of the 32 patients in the invasive group, 30 (94%) underwent early angiography, 27 (84%) PTCA, and one (4%) CABG. Twenty-two (69%) died within 30 days in the invasive group vs 18/23 (78%) in the medically managed group (ns, RR=0.88, 95% confidence interval 0.6-1.2). Among the registry patients, 24/51 were excluded from randomization solely because of patient or physician preference for the invasive approach: 23 (96%) of them underwent emergency angiography, 21 (88%) PTCA, and 12 (50%) died within 30 days. Among the remaining registry patients (n=27) only nine (33%) underwent early angiography, nine (33%) PTCA and 20 (74%) died. CONCLUSION: We failed to demonstrate that emergency PTCA significantly improves survival in patients with acute myocardial infarction and early cardiogenic shock. Because the study was stopped prematurely, due to an insufficient patient inclusion rate, a clinically meaningful benefit of early reperfusion may have been missed.

Aged↗
PubMed1998

Transcatheter closure of atrial septal defect and patent foramen ovale with ASDOS device (a multi-institutional European trial).

A clinical trial was conducted to assess the feasibility, safety, and efficacy of the atrial septal defect (ASD) occlusion system for transcatheter closure of secundum ASD and patent foramen ovale (PFO) after episodes of cerebral embolism. Occlusion was attempted in 200 patients aged 1 to 74 years (mean 32). The procedure failed in 26 patients (13%); the device was retrieved through a catheter in 20 and through surgery in 6 patients. Procedure-related complications necessitating surgical removal of the device included device embolization in 2, device entrapment within the Chiari network in 1, frame fracture in 1, and perforation of atrial wall in 2. All 6 patients experienced an uneventful postoperative course. An additional 11 patients (6%) underwent surgical removal of the device during follow-up. There were 163 patients (81%) with an implanted ASD occlusion system at follow-up of from 6 to 36 months (mean 17). Thrombus formation around the device was detected by transesophageal echocardiography in 9 patients 1 to 4 weeks after implantation. One of these patients (who had a coagulation factor XII deficiency) suffered a cerebral thromboembolism. Late atrial wall perforation (5, 6, and 8 months after implantation) occurred in 3 adult patients. Infectious endocarditis developed in 2 adult patients (1%). No late device embolization and no atrioventricular valve injury occurred. An asymptomatic device frame fracture was found in 14% and frame deformity in 4% of all patients during the follow-up period of >230 patient-years. Immediately after closure, a moderate/large residual shunt remained in 8% and a small shunt in 29% of patients. After 1 year, a moderate/large shunt was present in 2% and a small one in 26% of patients. During a total follow-up of 49 patient-years, only 1 of 46 patients with PFO had a transient neurologic event after the closure. The study indicates that patients with centrally situated secundum ASD and those with PFO after cerebral embolism can be treated with this system with a high success rate and an acceptable morbidity.

Adolescent↗
PubMed1998

Randomized evaluation of anticoagulation versus antiplatelet therapy after coronary stent implantation in high-risk patients: the multicenter aspirin and ticlopidine trial after intracoronary stenting (MATTIS).

BACKGROUND: Although the association of ticlopidine and aspirin has been shown to be superior to anti-vitamin K agents and aspirin after coronary stent implantation in low-risk patients, the latter combination has remained an unproven reference regimen for high-risk patients until recently. METHODS AND RESULTS: We randomized 350 high-risk patients within 6 hours after stent implantation to receive during 30 days either aspirin 250 mg and ticlopidine 500 mg/d (A+T group) or aspirin 250 mg/d and oral anticoagulation (A+OAC group) targeted at an international normalized ratio of 2.5 to 3. The primary composite end point was defined as the occurrence of cardiovascular death, myocardial infarction, or repeated revascularization at 30 days. Patients were eligible if (1) the stent(s) were implanted to treat abrupt closure after PTCA; (2) the angiographic result after implantation was suboptimal; (3) a long segment was stented (>45 mm and/or >/=3 stents); or (4) the largest balloon inflated in the stent had a nominal diameter of </=2.5 mm. The primary cardiac end point was reached for 10 patients (5.6%) in the A+T group and 19 (11%) in the A+OAC group (relative risk [RR], 1. 9; 95% CI, 0.9 to 4.1; P=0.07). Major vascular and bleeding complications were less frequent in the A+T group (3 patients, 1.7%) than in the A+OAC group (12 patients, 6.9%) (RR, 4.1; 95% CI, 1.2 to 14.3; P=0.02). CONCLUSIONS: High-risk patients should be treated with A+T rather than A+OAC after coronary stenting because the bleeding and vascular complications are significantly reduced and there is a marked trend suggesting a decrease in cardiac events.

Adult↗
PubMed1998

Clinical experience with the percutaneous hemopump during high-risk coronary angioplasty.

The percutaneous Hemopump showed beneficial effects during coronary angioplasty in 32 high-risk patients with unloading of the left ventricle during ischemia and maintaining cardiac output with mean aortic pressures of 50 mm Hg in case of cardiac arrest (3 patients). High procedure-related morbidity (occlusion of femoral artery in 2 patients; bleeding with need of transfusion in 4 patients) and mortality (4 of 32 patients) rates demonstrate the need for a very careful selection of patients.

Adult↗
PubMed1998

[Acute myocardial infarct in Switzerland: results from the PIMICS Heart Infarct Register. PIMICS Project (Prospective Ischemia Myocardial Infarction Captopril Survey)].

The aim of the PIMICS project was to create, for the first time in Switzerland, a registry of data concerning epidemiology and therapy in patients hospitalised for acute myocardial infarction covering all regions of the country. During 1995/96 73 Swiss hospitals of all categories took part in the PIMICS project. The ratio between males and females in the 3877 registered patients was 2.6:1 (2791 men vs. 1086 women). Female patients were significantly older than males (70.4 +/- 12.0 years vs. 63.4 +/- 12.6 years; p < 0.0001). The prevalence of risk factors differed between men and women: significantly more women had hypertension or diabetes, whereas smoking was more prevalent in males. The median delay between onset of symptoms and arrival at the hospital was 5.5 hours. Thrombolysis and primary angioplasty were more frequently performed in men (40.4% vs. 31.2% in women, p < 0.0001, and 5.7% in men vs. 3.5% in women, p = 0.005 respectively). During the acute phase males were treated more frequently with betablockers. The overall in-hospital mortality was 9.1%. It was significantly higher in female patients (13.5% vs. 7.4% in men; p < 0.0001) and in patients with reinfarction (14.5% vs. 7.1%; p < 0.0001). The mean hospital stay was 12.6 +/- 5.3 days. Only 7.7% of all patients with acute myocardial infarction were discharged within 6 days. At discharge, 51.7% were treated with betablockers and 69.3% with aspirin; 44.8% received ACE-inhibitors and only 13.8% lipid-lowering drugs. Follow-up measures such as coronary angiography and/or angioplasty or bypass surgery were performed significantly more often in males (45.0% vs. 32.9%; p < 0.0001). Likewise, men were more frequently assigned to a rehabilitation program than women (38.2% vs. 32.9%; p = 0.0004). The pre-hospital delay in patients with acute myocardial infarction remains too long. Primary and secondary prevention should be intensified in high risk groups, particularly in females. Thrombolysis and primary angioplasty as mainstays of treatment in acute myocardial infarction are generally used too sparingly, especially in women. With such measures the hospital stay could be shortened further.

Adult↗
PubMed1998

Differentiation of recent and old cerebral infarcts by diffusion-weighted MRI.

We performed MRI, including diffusion-weighted imaging, in 15 patients with recurrent strokes with acute ischaemia and at least one old lesion according to the clinical history and/or CT. Routine MRI showed similar signal intensity changes in both situations. Diffusion-weighted images, however, were positive in all acute or subacute infarcts. The high signal of acutely disturbed diffusion due to intracellular oedema could also be identified in small brain stem lesions. Spatial resolution was increased by applying separate gradients in each axis instead of creating anisotropy-independent trace images.

Adult↗
PubMed1998

Does acute exposure to the electromagnetic field emitted by a mobile phone influence visual evoked potentials? A pilot study.

To search for a potential negative influence on the central nervous system (CNS) of the electromagnetic field emitted by a mobile phone, the authors performed a pilot experimental study of the influence of a single short acute exposure to the GSM mobile phone Motorola 8700, using visual evoked potentials (VEP) examination as an electrophysiological marker of CNS dysfunction. The study group consisted of 20 healthy volunteers. The duration of exposure was 5 minutes. The output power of the device was 1.5 W when the antenna was pulled up. Five parameters of VEP were evaluated by means of multifactorial ANOVA. Confounding effects of age, sex, and of the call in itself were taken into consideration. No statistically significant influence of the above-described exposure to the electromagnetic field emitted by the mobile phone on latencies or amplitudes of VEP was observed.

Adult↗
PubMed1997

Magnum wire for percutaneous coronary balloon angioplasty in 800 total chronic occlusions.

The experience in consecutive procedures with 800 recanalization attempts of chronic total coronary occlusions using the Magnum wire was analyzed from a prospectively constituted computerized database. The data confirm that the Magnum wire, generally used as a primary intervention for occlusive angioplasty at our centers, is competitive with conventional systems in this setting.

Angioplasty, Balloon, Coronary↗
PubMed1997

[Thrombolysis in acute myocardial infarct in everyday clinical practice].

We prospectively included in a database all thrombolyzed acute transmural myocardial infarction patients admitted to our hospital from November 1986 to September 1995. Six hundred and twenty-seven patients (497 males) with a mean age of 61 +/- 12 years (range 26-88 years) were included. 87% were having their first acute myocardial infarction. Different thrombolytic regimens were applied in the emergency room but the vast majority (92%) received t-PA. The median delay between the onset of pain and admission was 2 h 0 min (10 min-22 h). The median admission to treatment time was 40 min (5 min-6 h 20 min). The latter has been shortened (median 55 min from 1986 to 1989 versus 35 min from 1990 to 1995, p < 0.05) during the study period. The rate of intracerebral hemorrhage was 2.4% (confidence interval 1.1-3.5%) and no significant predictor could be found, although patients with cerebral bleeding tended to be slightly older (66 +/- 9 years vs 61 +/- 13 years, p = ns). The rate of false diagnosis was only 4.6%, even when patients with a final diagnosis of unstable angina and/or aborted acute myocardial infarction were included. The in-hospital mortality was 8.8%, a rate similar to those reported in the literature. Using multivariate analysis, negative prognostic factors were higher age (p < 0.001), advanced Killip class at admission (p < 0.001) and elevated peak CPK levels (p < 0.001). These results confirm that thrombolysis for acute myocardial infarction in the emergency room can be done with a short admission-to-treatment time and with an acceptably low rate of false diagnosis. However, our intracerebral hemorrhage rate was clearly higher than generally reported in the literature and may be explained by a different patient selection from that in large randomized studies.

Adult↗
PubMed1997

Cloning, yeast expression, and characterization of the coupling of two distantly related Arabidopsis thaliana NADPH-cytochrome P450 reductases with P450 CYP73A5.

Two NADPH-cytochrome P450 reductase-encoding cDNAs were isolated from an Arabidopsis cDNA library by metabolic interference in a Saccharomyces cerevisiae mutant disrupted for its endogenous cpr1 gene. ATR1 encodes a protein of 692 amino acids, while ATR2 encodes either a 712-residue protein (ATR2-1), or a 702-residue protein (ATR2-2) depending on the choice of the initiation codon. Comparative analysis of ATR1 and ATR2-1 indicates 64% amino acid sequence identity and the absence of conservation in the third base of conserved amino acid codons. The two Arabidopsis reductases are encoded by distinct genes whose divergence is expected an early event in angiosperms evolution. A poly(Ser/Thr) stretch reminiscent of a plant chloroplastic targeting signal is present at the ATR2-1 N-terminal end but absent in ATR1. The cDNA open reading frames were expressed in yeast. The recombinant polypeptides were found present in the yeast endoplasmic reticulum membrane and exhibited a high specific NADPH-cytochrome c reductase activity. To gain more insight into the respective functions of the two reductases, the Arabidopsis cDNA encoding cinnamate 4-hydroxylase (CYP73A5) was cloned and co-expressed with ATR1 or ATR2 in yeast. Biochemical characterization of the Arabidopsis ATR1/CYP73A5 and ATR2-1/CYP73A5 systems demonstrates that the two distantly related Arabidopsis reductases similarly support the first oxidative step of the phenylpropanoid general pathway.

Amino Acid Sequence↗