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Biomedical subjects

D Liermann

Publications and source records attributed to D Liermann.

At least 37 records · Page 2Linked to original sources

[Minimally invasive stereotactic breast biopsy with the "mammotome". Methodology and personal experiences].

A new method of minimally invasive breast biopsy is described. The system components are a stereotactic biopsy table, a digital mammography, an automatic, computer-assisted needle positioning device and a new vacuum core biopsy needle. With this needle multiple core biopsies can be collected through a single insertion. The procedure was performed as outpatient status and was very well tolerated by the patients. Our experiences with this method are very promising. The method will reduce the relation of benign to malignant histology in open biopsies.

Biopsy, Needle↗

Evaluation of caffeine as a test drug for CYP1A2, NAT2 and CYP2E1 phenotyping in man by in vivo versus in vitro correlations.

Caffeine is used to phenotype subjects in vivo for the cytochrome P450 isoforms CYP1A2 and CYP2E1, and for N-acetyltransferase type 2 (NAT2). However, how much of the variation in phenotyping parameters may be attributed to variations in CYP1A2 and CYP2E1 activities has not been determined. Therefore, this study intraindividually compared enzyme activities and/or content in liver samples with pharmacokinetic parameters of caffeine in vivo after administration of a test dose in 25 patients undergoing hepatectomy. Parameters measured in vitro were the high affinity components of caffeine 3-demethylation and phenacetin 0-deethylation, microsomal CYP1A2 and CYP2E1 immunoreactivity, and cytosolic sulfamethazine N-acetylation. Caffeine parameters in vivo included caffeine clearance from plasma and/or saliva, paraxanthine/caffeine ratios in plasma and saliva, plasma theophylline/caffeine ratio, and several metabolite ratios from spot urine sampled 6 h postdose. Correlations between parameters were determined using weighted linear regression analyses. Caffeine clearance and paraxanthine/caffeine ratios correlated most highly to intrinsic clearance of caffeine 3-demethylation and to CYP1A2 immunoreactivity (r= 0.584-0.82), whereas urinary CYP1A2 ratios correlated less strongly with CYP1A2 parameters in vitro. Assignment of acetylator phenotype by urinary NAT2 ratios was concordant with sulfamethazine-N-acetylation in vitro. In contrast to CYP1A2 parameters in vitro, CYP2E1 immunoreactivity was not related to the theophylline/caffeine plasma ratio. CYP1A2 activity, thus, is the major determinant of caffeine clearance and the paraxanthine/caffeine ratios in vivo, of which the saliva ratio 6 h postdose appears as the most advantageous parameter. The results confirm that phenotyping using caffeine provides valid estimates of CYP1A2 and NAT2 activity.

Aged↗

Balloon dacryocystoplasty: an alternative treatment for obstructed tear ducts.

Twenty-two patients with severe epiphora due to relative (n = 13) or absolute (n = 9) stenoses of the nasolacrimal duct were treated by means of radiologically guided balloon dacryocystoplasty. The recanalization was performed with a steerable microguide wire with flexible tip, which was advanced through the lacrimal draining system and manipulated out of the nasal cavity. A 3-mm PTA balloon was then introduced from the nasal site. In 20 of 22 cases the procedure was technically successful. Dacryocystography proved a normal lumen in 9 of 20 patients and an improvement without impairment of flow in another 8 cases. Two months after dilation a clear regression of epiphora could be demonstrated in 17 of 20 patients. The procedure was complicated by the occurrence of 2 reobstructions within the first 3 months; other serious side effects were not observed.

Adult↗

Endovascular irradiation--a new method to avoid recurrent stenosis after stent implantation in peripheral arteries: technique and preliminary results.

PURPOSE: A high dose rate (HDR) afterloading technique for prevention of vascular stenosis or occlusion after percutaneous transluminal arteriography and subsequent stent implantation caused by intimal hyperplasia is presented. METHODS AND MATERIALS: The frequency of recurrent stenosis or occlusion following implantation of stents into peripheral arteries is relatively high. The cause of relapse is rapid intimal hyperplasia. To prevent proliferation of the intimal layer, intravascular brachytherapy was performed in cases of recurrent vascular occlusion or severe stenosis. After recanalization by percutaneous transluminal angioplasty and stent implantation, a 9-French-ReKa catheter was placed within the lumen of the stent. This catheter served as a guide for a 5-French flexible applicator. Then after individual calculation of the isodose, 12 Gy were applied to the vessel wall. This procedure was followed by 72 h of heparinization. Follow-up by Doppler digital subtraction angiography and magnetic resonance imaging was done 3, 6, and 12 months after the procedure and later on once a year. RESULTS: Intraluminal irradiation was performed in 13 patients (nine male and four female). All patients had a clinically relevant restenosis or reocclusion in the superficial femoral artery (clinical stage according to Fontaine IIb-III). Follow-up time ranged from 3-27 months. After irradiation the stented area remained patent in all cases and there were no signs of recurrent stenosis in the treated arterial segment. CONCLUSION: With high dose rate 192Ir afterloading after percutaneous transluminal angioplasty and subsequent stent implantation restenosis or reocclusion caused by intimal hyperplasia can be prevented.

Aged↗

Absorption of ipsapirone along the human gastrointestinal tract.

Isapirone-HCl (5 mg) was administered orally, rectally and locally, by a remote control drug delivery device (HF-capsule) into different segments of the gastrointestinal tract, to four young healthy male adults. The relative systemic bioavailability of the drug from the colon and rectum was 2-3-fold greater than that from the upper gastrointestinal tract. This supports a rationale for a prolonged-release formulation.

Administration, Oral↗

Noninvasive methods in the early detection of restenosis after percutaneous transluminal angioplasty in peripheral arteries.

In a prospective study, several noninvasive methods were evaluated in the early detection of restenosis after percutaneous transluminal angioplasty in peripheral arteries. Sensitivity and specificity of various noninvasive resting and exercise methods for the detection of restenosis were determined. It is concluded that noninvasive follow-up after percutaneous transluminal angioplasty in peripheral arteries requires exercise testing with determination of ankle-arm index or segmental arterial pulse oscillography for the early detection of restenosis.

Aged↗

[Intervention and clinical aspects combined with endovascular irradiation of intimal hyperplasia of the vascular system].

After implantation of stents in femoropopliteal arteries we found restenosis or occlusions by intimal hyperplasia in up to 40% especially in the hunter's channel. Repeated balloon angioplasty and prophylactic endovascular radiotherapy with a surface dose of 12 Gy in the vessel wall using an iridium 192 source in the same investigational session is a new technique to reduce or eliminate further recurrence. All 18 patients had developed recurrent stenoses or occlusions 6-8 months after original stent implantations. The patients have not redeveloped recurrent obstructions after this treatment, which up to date showed no short term or long term complications. We conclude that the encouraging results of this pilot study justify further randomized trials.

Aged↗

[Noradrenaline-assisted selective chemoembolization of hepatocellular carcinoma].

Despite the postulated tumour affinity of Lipiodol is liver dysfunction after chemoembolization of hepatic malignancies common. Vasoconstricting action of noradrenaline to protect non malignant tissue was studied. 70 patients with unresectable HCCs (UICC IV: 61%) were treated via percutaneous catheter. After noradrenaline (0.1-0.8 mg) induced and documented vessel constriction a suspension of Lipiodol (5-8 ml) and Mitomycin C (10-20 mg) was injected. In addition minced dehydrated dura suspended in Lipiodol occluded the major tumour feeding vessels. 120 (73%) of a total of 164 chemoembolizations were performed after intrahepatic noradrenaline (0.1-0.8 mg) bolus injection. Arterial perfusion of non malignant liver parenchyma was significantly reduced in 95%. 24 hours later selective tumor retention of lipiodol was noticed in 67%. Side effects were fever (79%), thoracoabdominal pain (67%), nausea and emesis (43%) and tachycardia (15%). There were two treatment related deaths: one each from liver failure and cardiac arrest. By WHO response criteria there were 17 (23%) partial remissions (PR), 34 (49%) stable diseases (SD) and 20 (28%) patients had progression (PD). The median survival time from initiation of treatment was 312 days. Bilobal and multiple tumors reduced survival time (90 days). These findings suggest that noradrenaline guided chemoembolization is feasible in Europe and even in patients with pylethrombosis well tolerated.

Adult↗

Current status of the Strecker stent.

Knitted flexible tantalum stents proved to be a valuable adjunct to percutaneous transluminal angiplasty (PTA) in the case of insufficient PTA results, and their use was established in the distal aorta, the iliac, the femoro-popliteal, the renal, and the coronary arteries. Recently, long arterial occlusions were defined as new indications for primary stenting; stent indications were further extended to the subclavian, the carotid, and the splanchnic arteries. Due to higher incidence of acute and late complications after stent treatment of small diameter arteries, patients have to be selected thoroughly. Newly designed drug-releasing stents tested in animal experiments promised to be suitable to diminish the incidence of late restenosis due to intinal hyperplasia, thus providing better long-term patency.

Angioplasty, Balloon↗

[Reopening chronic arterial occlusions].

Chronic complete occlusions still represent the major technical limitation of percutaneous transluminal balloon angioplasty, both in peripheral and coronary vessels. The clinical use of low speed rotational angioplasty (ROTACS) started in 1986 for the peripheral and in 1987 for the coronary vessels, and has already become part of the clinical routine in several centers. Up to now, more than 300 patients with peripheral and more than 200 patients with coronary occlusions were treated in Frankfurt. In peripheral occlusions the acute success rate was more than 80% if used as the first attempt; after failure of conventional techniques still more than 60% of the vessels could be recanalized successfully. In addition to occlusions of the arteries of the lower limbs, the indication now includes the iliac artery and several other indications are under investigation. In each of the patients with chronic coronary occlusions an attempt with conventional techniques had failed before. Following a learning curve, which was also influenced by a better understanding of morphological preconditions, the acute success rate has now reached 70%. Both in patients with peripheral and those with coronary occlusions no deaths occurred. First angiographically documented long-term results in both indications are comparable to conventional balloon angioplasty. It is concluded that the use of low speed rotational angioplasty (ROTACS) can improve the results of nonoperative invasive treatment, both in peripheral and in coronary arteries.

Angiography↗

[Vascular problems in patients with transplants from the interdisciplinary viewpoint].

From 1979 to 12/1990 795 organ transplants have been performed at our hospital (kidney n:737, liver n:23, heart n:35). Our data reveal vascular problems in 10 percent of the transplanted patients - not concerning the vascular anastomosis. The therapeutic approach should be determined interdisciplinary. Due to the low complication rate of operative or interventionel procedures in this patients, even relative indications--to improve "quality of live"--can be accepted.

Adult↗

[Salvage of balloon expanded vascular endoprostheses (stents)].

Since 1987 patients have been treated with tantalum stents at our hospital (iliac arteries n:40, femoro/popliteal arterie n:35). Before expanding indication for stent implantation to other more difficult areas and vessel segments, we need to guarantee that a misplaced or not sufficient expanded or only temporary used stent, perhaps after dissections, could be rescued out of the vessel without damage of the vessel wall. Therefore we used cadaveric arteries and a special "retrivel set" To rescue the expanded stent through the introducer sheet without wessel wall damage was possible in all cases (iliac arteries n:5, femoral arteries n:5). In a second attempt, we showed, that even a TEA was possible, using a ringstripper which cut a typical cylinder of the atheriosclerotic vessel wall overpassing and including the stent. In 7 out of ten cases (cadaveric iliac arteries) the retrograde ringstripping-procedure was successful. The other 3 cases required an incision of the vessel with local thrombendarteriectomia. Insofar a stent implantation should not be considered as a contraindication for this surgica treatment else in later history.

Angioplasty, Balloon↗

Expandable tubular stents for treatment of arterial occlusive diseases: experimental and clinical results. Work in progress.

The balloon-expandable vascular prosthesis consists of a flexible, knitted tantalum wire mesh tube. To demonstrate its pliability, this prosthesis was tested experimentally in 10 mongrel dogs by implanting it into the proximal femoral arteries. The maximum follow-up time was 1 year. On the basis of the experimental results, in which there was no relevant stenosis, occlusion, or migration of the vascular prosthesis, nine patients were treated: one with iliac artery occlusive disease and eight with superficial femoral artery (SFA) occlusive disease (four reocclusions after angioplasty and four unsatisfactory primary angioplasty results). One SFA lesion was treated with the crossover method from the contralateral side. All implants remained patent without hemodynamically significant stenoses, with the longest observation time being 6 months. Flexible, expandable vascular prostheses are promising adjuncts to angioplasty.

Aged↗

[Chemoembolization of primary liver cancer].

At the University of Frankfurt/M. we perform chemoembolization of the liver in patients with inoperable liver cell carcinoma. Before application of embolization material vasoconstriction of healthy blood vessels is achieved by intraarterial injection of norepinephrine. This procedure improves selectivity of tumor embolization. Methods, indications, contraindications and results are presented.

Carcinoma, Hepatocellular↗

Absorption differences of ciprofloxacin along the human gastrointestinal tract determined using a remote-control drug delivery device (HF-capsule).

The single-dose absorption kinetics of ciprofloxacin in different regions of the human gastrointestinal tract were investigated using a remote-control drug delivery device (HF-capsule). Doses of 180 to 200 mg ciprofloxacin (as a lactic acid solution) were placed in the HF-capsule and administered to four healthy male adults. The position of the HF-capsule in the gastrointestinal tract was checked via radiographic examination. The release of the solution from the HF-capsule was induced by a radio signal. In each volunteer, the solution was released into five different regions of the gastrointestinal tract: the stomach (B), jejunum (C1), ileum (C2), ascending colon (D1), and descending colon (D2). Two control runs (A1, A2), involving oral administration of the solution, were used as a reference for calculation of area under the curve. The oral administration of a conventional 250-mg tablet (A3) was also studied. The plasma concentration of ciprofloxacin and urine concentrations of ciprofloxacin, desethylene- (M1), sulfo- (M2), and oxociprofloxacin (M3) were determined fluorimetrically by high-performance liquid chromatography. Intraindividual comparisons indicated a progressive decrease in the amount of ciprofloxacin absorbed (100 percent = mean of AUCA1 and AUCA2) from the jejunum (-61 percent, median), ileum (-75 percent), colon ascendens (-90 percent), and colon descendens (-95 percent). Absolute amounts of renally excreted ciprofloxacin and metabolites decreased due to the reduced absorption of ciprofloxacin, but the metabolite pattern was unchanged. It is concluded that the main absorption site for ciprofloxacin is the upper part of the intestinal tract (duodenum, jejunum).

Adult↗