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Biomedical subjects

G Wendt

Publications and source records attributed to G Wendt.

At least 37 records · Page 2Linked to original sources
PubMed1996

Aortic and iliac stenoses: follow-up results of stent placement after insufficient balloon angioplasty in 118 cases.

PURPOSE: To demonstrate follow-up results of stent placement in aortic and iliac stenoses. MATERIALS AND METHODS: A total of 109 patients with 118 aortoiliac stenoses underwent placement of self-expanding stents. Mean length of the stenotic segments was 3 cm +/- 2 (standard deviation). Mean ankle-arm index at rest was 0.58 +/- 0.2. A total of 101 patients were followed up angiographically or clinically. RESULTS: A mean of 1.2 stents +/- 0.5 were inserted per case. Clinical stage improved in 112 cases; it improved two or more stages in 89 cases. Mean ankle-arm index improved to 0.92 +/- 0.17. Total and major complication rates were 6.8% and 3.4%, respectively. Subacute occlusion occurred in four patients. Late stent obstruction occurred after a mean of 27 months (range, 16-48 months) in 10 cases. Primary patency was 95% after 1 year and 88% after 2 years; 4-year patency was 82%. Secondary patency was 96% after 1 year and 93% after 2 years. Three- and 4-year secondary patency were both 91%. CONCLUSION: Placement of self-expanding stents in iliac stenoses is technically safe and offers sufficient follow-up patency.

Angiography, Digital Subtraction↗
PubMed1996

Excretion and metabolism of remikiren, a potent orally active inhibitor of primate renin.

1. Following intravenous administration of 14C-remikiren to the male rat, 78% of the administered radioactivity was recovered in faeces, indicating high biliary elimination. Of the 25 +/- 0.1% of the dose recovered in urine, the majority (16.5% of dose) was intact drug. 2. After oral administration to the male rat the urinary recovery was markedly reduced (8.5 +/- 2.0% of dose), and virtually all of the material was excreted as an inactive hydrolysis product. Intact drug was non-detectable, suggesting extensive first-pass metabolism. 3. Perfusion of isolated rat liver confirmed high biliary elimination, coupled with extensive metabolism. Although intact remikiren was the major component in bile (20% of the 'dose'), the majority of the radioactivity was recovered as a series of mono- and di-hydroxylated metabolites. 4. When screened against human renin, only one of the metabolites in bile and urine (mono-hydroxylated in the t-butyl side chain, and synthesized as Ro 44-0444) showed comparable activity to remikiren. The remaining ten metabolites tested were at least one order of magnitude less active than the parent drug. 5. In comparative in vitro studies Ro 44-0444 was formed by rat, but not human or cynomolgus monkey, liver microsomes. The primate microsomes also produced more of the remaining mono- and di-hydroxy products, suggesting that metabolites make little contribution to the oral activity of remikiren which is observed in these species in vivo.

Administration, Oral↗
PubMed1995

[Therapy of an abdominal aortic aneurysm using transfemoral endovascular implantation of a bifurcation prosthesis].

Transfemoral intraluminal placement of a woven-dacron bifurcation prosthesis was undertaken to bridge an infrarenal aortic aneurysm (4.6 cm diameter) in a 65-year-old man with chronic coronary heart disease. The Chuter-Gianturco introducing system was used via the right femoral artery to anchor the prosthesis immediately below the origins of the renal arteries. After fixing the right branch of the prosthesis the left one was secured via the left femoral artery. No leakage was demonstrated on the 7th post-operative day and the aneurysm was satisfactorily bridged. Regular follow-up tests showed a normal circulation. Spiral computed tomography after 18 months confirmed complete thrombosis of the aneurysm.--This case shows that the described method is a promising alternative in the treatment of abdominal aneurysm.

Aged↗
PubMed1995

Transfemoral insertion of a bifurcated endovascular graft for aortic aneurysm repair: the first 22 patients.

The purpose of this study was to evaluate and optimize a system of transfemoral bifurcated graft insertion for endovascular repair of infrarenal aortic aneurysm. Grafts were inserted through bilateral femoral arteriotomies in 22 patients. Placement was guided by fluoroscopy. Results were assessed by completion angiography, with computed tomography scanning or duplex ultrasonography at 1, 3 and 6 months. The first 11 insertions were complicated by failed insertion in two cases, proximal leakage in one, graft limb thrombosis in five and wound infection in one. The second 11 insertions were complicated by retrograde leakage around the distal graft orifice in two patients. One of these was associated with aneurysm rupture, leading to the sole mortality of the series. There were no instances of graft migration or embolism. In conclusion, the lessons learned during the first 11 insertions were responsible for the improved results apparent in the second 11 insertions. When applied in properly selected patients, transfemoral insertion of a bifurcated graft is a reliable method of isolating an aortic aneurysm from the circulation.

Aortic Aneurysm, Abdominal↗
PubMed1995

Primary stent placement for chronic iliac artery occlusions: follow-up results in 103 patients.

PURPOSE: To report results of primary stent placement for treatment of chronic iliac artery occlusions. MATERIALS AND METHODS: The authors placed 154 primary stents in 103 patients with iliac artery occlusions of at least 3 months duration. Mean length of the occluded segments was 5.1 cm. All patients had symptoms, with claudication or trophic changes. Mean ankle-arm index at rest was 0.48. Follow-up included angiography, Doppler ultrasound, and clinical examination. RESULTS: Ninety-nine patients demonstrated clinical improvement, with relief or improvement of claudication. Complications that required percutaneous or surgical intervention occurred in six patients; minor complications occurred in another six. Embolization occurred in five patients. Primary patency was 87% after 1 year, 83% after 2 years, and 78% after 4 years; secondary patency was 94%, 90%, and 88% at 1 year, 2 years, and 4 years, respectively. CONCLUSION: Primary stent placement should be the treatment of choice in unilateral chronic iliac artery occlusion.

Angiography, Digital Subtraction↗
PubMed1995

Late reobstruction in iliac arterial stents: percutaneous treatment.

PURPOSE: To retrospectively analyze in a nonrandomized fashion the efficacy of percutaneous reintervention in obstructed iliac stents. MATERIALS AND METHODS: In 21 symptomatic patients with iliac lesions, 26 reinterventions (16 for stent occlusion and 10 for stent stenosis) were performed. Restenoses were treated with balloon dilation and either atherectomy or stent placement. Reocclusions were treated with atherectomy or aspiration thrombectomy and then recanalization with balloon dilation and selective stent placement. RESULTS: Balloon angioplasty for stent stenosis was effective in all but one patient. Recanalization was successful in 14 of 16 patients with stent occlusion. The mean period of patency after reintervention was 18 months +/- 15. Cumulative stent stenosis patency after reintervention was 87% after 1 year. Stent occlusion patency was 57%. Recurrent stent obstruction occurred in eight of 24 (33%) patients with successful primary interventions. CONCLUSION: Percutaneous reintervention for both stent stenosis and occlusion is feasible with a moderate complication rate and may be attempted before surgery.

Angioplasty, Balloon↗
PubMed1994

Bifurcated stent-grafts for endovascular repair of abdominal aortic aneurysm. Preliminary case reports.

This report describes the first clinical experience with transfemoral insertion of an endovascular bifurcated graft for repair of an abdominal aortic aneurysm. Graft placement was performed through bilateral femoral arteriotomies. There was no graft migration, no leakage, and unobstructed flow to the common iliac arteries was documented by angiography and Duplex ultrasonography in both cases. Both patients were eating a normal diet and ambulating on the first postoperative day.

Aged↗
PubMed1994

One-stage intrathoracic repair of extended aortic aneurysms.

Aneurysms of the entire thoracic aorta are usually approached in two to three stages. From 1990 to 1994, we performed one-stage aortic replacement from the root to the diaphragm in 16 patients (8 men and 8 women with a mean age of 55.7 years, range 49 to 73). There were 11 type A dissections, 7 of which were acute. Six patients underwent aortic valve reconstruction; seven had aortic root replacement by Bentall or Cabrol techniques. In two cases, the innominate artery had to be replaced by a vascular graft separately in addition to reimplantation of the supraaortic branches as an island flap into the arch prosthesis. In eight cases, a median sternotomy was used; eight had a bilateral transverse thoracotomy. The procedure was performed under deep hypothermic circulatory arrest in all cases (mean duration 50.5 min, range 38 to 62 min). Two patients, both operated upon for an acute dissection, expired perioperatively: one due to a bronchopneumonia, and one because of a thrombosed Cabrol graft to the right coronary artery. No patient developed bleeding or neurological complications. At a mean follow-up of 26.9 months (1 to 50 months), all patients discharged from the hospital were still alive. Four patients underwent subsequent thoracoabdominal aortic replacement. This experience suggests that complete thoracic aortic replacement can be performed in a single session with an operative risk comparable to that of the conventional two-stage approach. The bilateral transverse thoracotomy affords excellent exposure. The lack of spinal cord ischemia may be the result of spinal cord protection with hypothermic circulatory arrest and use of the open-clamp technique.

Acute Disease↗
PubMed1994

Ulcerated plaques and focal aneurysms of iliac arteries: treatment with noncovered, self-expanding stents.

OBJECTIVE: We studied the value of noncovered, self-expanding stents for treatment of ulcerated plaques and focal aneurysms of iliac arteries. MATERIALS AND METHODS: Seventeen patients with ulcerated plaques (n = 13) and aneurysms (n = 5) were treated with noncovered, self-expanding Wallstent endoprostheses. A total of 18 lesions were stented. The lesions were in the common iliac artery (n = 10), the external iliac artery (n = 3), or affected parts of both arteries (n = 5). Their mean length was 3.5 +/- 1.0 cm. All lesions were accompanied by stenosis of the affected arterial segment. RESULTS: Occlusion of ulcerations or aneurysms occurred immediately in three cases and thereafter in the remaining 15 cases, as shown by angiographic follow-up. Embolization did not occur. Follow-up revealed a 4-year cumulative patency of 82%, with reobstruction of the stent in three cases. CONCLUSION: Noncovered stents are a rational approach to treating circumscribed aneurysms and ulcerated plaques of the iliac arteries. The stent regularly smoothens the vessel wall by sealing the ulcerated area or aneurysm immediately or soon after stent placement.

Aortic Dissection↗
PubMed1994

[Relative bioavailability of paracetamol in suppositories preparations in comparison to tablets].

Relative Bioavailability of Paracetamol as Suppositories Compared to Tablets. The relative bioavailability of paracetamol (CAS 103-90-2) in ben-u-ron 500 mg and ben-u-ron 1000 mg suppositories (test formulations) was compared with that of Benuron tablets 500 mg (reference product) in an open, intraindividual, 3-period-changeover-study in 18 healthy subjects. Plasma concentrations of paracetamol were determined using a specific and sensitive HPLC method with UV detection. For the assessment of bioavailability AUC, Cmax, tmax and HVD were used as pharmacokinetic characteristics. Bioequivalence of the rectal formulations was tested by calculating 90% confidence intervals using the Two-one-sided-t-tests-procedure and log-transformed data of AUC and Cmax. For AUC the confidence intervals were required to be in the 80 and 125% range, for Cmax between 70 and 143% (inclusion rule). Data from 17 subjects could be evaluated. Bioavailability of paracetamol was 89 and 90% for the 500 and 1000 mg suppositories, respectively compared with that of the 500 mg reference tablets. Mean maximum paracetamol plasma concentrations (Cmax) were 3.55 and 6.02 or 7.16 mg/l after administration of the 500 and 1000 mg suppositories or the 500 mg tablets, respectively. These maximum concentrations were achieved 2.0, 2.7 and 0.6 h (tmax) after administration of the respective preparations. The corresponding HVD values were 4.3, 5.2 and 2.0 h, respectively. After dose adjustment of the results for the 1000 mg suppositories relative bioavailabilities of paracetamol from both rectal formulations exceeded 80% of that from the tablets.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaminophen↗
PubMed1991

Brofaromine--a selective, reversible, and short-acting MAO-A inhibitor: review of the pharmacological and clinical findings.

During recent years the MAO inhibitors have come to assume increasing importance in clinical practice. Attempts have been made to improve the tolerability of these substances by evolving a new generation of MAO inhibitors. Brofaromine, a newly developed MAO inhibitor of the second generation, is a selective, reversible, and short-acting MAO-A inhibitor. Under this drug, the dangerous "cheese effect" can be expected to occur only under extreme conditions, if at all. Clinical trials performed to date, including double-blind trials versus tranylcypromine and imipramine, have shown that brofaromine displays good antidepressive efficacy and good tolerability.

Animals↗
PubMed1991

Pharmaco-EEG profile of levoprotiline: second example to discuss the predictive value of pharmaco-electroencephalography in early human pharmacological evaluations of psychoactive drugs.

The present paper forms the second part of a critical evaluation of the use of pharmaco-EEG as an instrument for assessing the profile of action of psychoactive drugs in man based on the trial results of three new psychoactive test substances. Part I described the basic principles and methodological approaches and illustrated the value of pharmaco-EEG in framing hypotheses about the therapeutic efficacy of psychotropic drugs by the example of the neuroleptic drug savoxepine. This chapter illustrates the relevance of pharmaco-EEG in the assessment of psychoactive drugs by reference to the test substance levoprotiline. Levoprotiline is the pure R-(-)-enantiomer of the racemic drug oxaprotiline, a successor to the second-generation antidepressant maprotiline. Only the S-(+)-enantiomer of oxaprotiline inhibits the re-uptake of noradrenaline. In view of the absence of any monoamine-uptake inhibiting action of levoprotiline, this drug was assumed to be devoid of an antidepressive action. This assumption, however, was disproved by observations made in clinical studies with depressive patients, in whom levoprotiline did indeed display antidepressive activity. Investigations of levoprotiline in the pharmaco-EEG model--even though being retrospective in the sequence of events--would have been able to produce objective prediction of antidepressive potential in man. The substance was tested by comparison to placebo and to the standard antidepressant imipramine in nine young, healthy male volunteers. The experimental design was a cross-over uncompleted block design with three consecutive trial days one week apart.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Pharmaco-EEG profile of maroxepine: third example to discuss the predictive value of pharmaco-electroencephalography in early human pharmacological evaluations of psychoactive drugs.

This publication forms the third part of a critical evaluation of pharmaco-EEG applications as an instrument for assessing the profile of action of psychoactive drugs based on the trial results of three new psychoactive test substances: savoxepine, levoprotiline and maroxepine. After the presentation, in Parts I (savoxepine) and II (levoprotiline), of trial substances for which compatible results were obtained in the pharmaco-EEG model and in the clinical studies, a case with discrepant and less predictive results has been presented, and on this basis the limitations of the pharmaco-EEG model in the evaluation of therapeutic efficacy are discussed. The substance examined in this report, the tetracyclic dibenzoxepine derivative, maroxepine, produced prominent central effects in pharmacological studies which pointed to a bipolar profile of action, i.e., the EEG showed similarities both to antidepressants and antipsychotics. The pharmaco-EEG effects of maroxepine were investigated in a randomised, double-blind study in 15 young healthy male subjects and compared with those of placebo and the reference substances, chlorpromazine and imipramine. The experimental design was a cross-over uncompleted block design with five consecutive trial days one week apart. The pharmaco-EEG was recorded from the occipito-temporal and frontocentral regions before, 3 and 6 h after application of 2.5 mg and 5.0 mg maroxepine, 75 mg chlorpromazine, 75 mg imipramine and placebo. The selected target variables for descriptive statistical evaluation were the Spectral Difference Index (SDI), the absolute and relative power values in seven predetermined frequency bands within the range 1.5 to 30.0 Hz, the dominant frequency (6.0 to 18.0 Hz) and the alpha slow-wave index (ASI). The results show that maroxepine has a potent central nervous action and a strong sedative potential. The EEG effects consisted of a shift to the left of the relative power spectrum of the occipital lead, accompanied by an increase in the absolute beta power in the frontocentral region. Discriminative inspection of the profiles of EEG changes, induced by maroxepine and the reference drugs, revealed closer similarity of maroxepine with chlorpromazine than with imipramine. Maroxepine showed vigilance-decreasing features like imipramine. This is one condition to be able to interfere with depressive illness. The underlying hypothesis is that depressive illness is based on affective and vigilance disturbance. Maroxepine furthermore showed the typical neuroleptic-like shift from resting alpha to resting subalpha (theta F band) which we assume related to the anti-productive properties of neuroleptics in schizophrenia.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

Doubleblind evaluation of the antimanic properties of carbamazepine as a comedication to haloperidol.

1. Today carbamazepine is the most important alternative to neuroleptic drugs for the treatment of manic psychoses. Often carbamazepine is administered as a comedication to a neuroleptic. 2. A doubleblind study with 20 patients suffering from manic or schizomanic psychoses was performed to determine whether carbamazepine and haloperidol in comedication are more effective than haloperidol alone. 3. Under the tested conditions (24 mg haloperidol p.d.) only the smaller amount of additional medication with levomepromazine in the experimental group gave evidence for the antimanic effect of carbamazepine in combination with haloperidol. 4. Especially the patients with pure manic psychoses seem to benefit from carbamazepine as an adjunct to haloperidol.

Adult↗
PubMed1989

Efficacy and tolerability of a new antipsychotic compound (savoxepine): results of a pilot-study.

Savoxepine is a new tetracyclic compound displaying potent neurolepticlike effects in pharmacological studies. Of particular interest is its preferential binding to dopamine-2 receptors in the hippocampus, which leads to the hypothesis that savoxepine may exert antipsychotic effects at doses not inducing extrapyramidal side-effects. In an open pilot-study 18 patients suffering from acute schizophrenic psychoses or paranoid syndromes were treated with savoxepine in an individually adapted dose range from 0.50 to 10 mg per day. A good antipsychotic efficacy could be demonstrated in 10 of 16 patients. Savoxepine was found to be generally well tolerated. Contrary to expectations, mild or moderate extrapyramidal side-effects, especially of the parkinsonian type, were registered. Future research has to test the suggested advantage of savoxepine in comparison with other neuroleptic drugs.

Adult↗