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R Prenzel

Publications and source records attributed to R Prenzel.

6 recordsLinked to original sources
PubMed2004

Sequential photodynamic therapy (PDT) and high dose brachytherapy for endobronchial tumour control in patients with limited bronchogenic carcinoma.

BACKGROUND: Bulky endobronchial tumours in patients with lung cancer are difficult to treat. Brachytherapy and photodynamic therapy (PDT) are variably effective, and the combination of these treatments is not often recommended. However, cell culture studies and animal studies indicate a possible synergistic effect of combining PDT with ionising radiation. We assessed the safety and effectiveness of combined brachytherapy and PDT in patients with bulky endobronchial lung cancer. METHODS: Patients with histologically proven non-small cell bronchogenic carcinoma and bulky endobronchial tumours were treated using a combination of PDT (Photofrin, 2 mg/kg) and brachytherapy. Six weeks after PDT, brachytherapy was applied with five fractions of 4 Gy at weekly intervals. Follow up was performed with standard and autofluorescence bronchoscopy and tissue biopsies every 3 months. RESULTS: Thirty two patients were treated. Tumours were extensive with lengths ranging from 10 to 60 mm along the bronchus and estimated volumes ranging from 40 to 3500 mm3. At a mean follow up of 24 months, 26 patients were free of residual tumour and local recurrence. The remaining patients received a second treatment with PDT, brachytherapy, Nd:YAG laser coagulation, or external beam radiation. Distant metastases (lung, lymph node) developed in two of the six patients. Currently, all 32 patients are well. There is no evidence of residual or local recurrent endobronchial cancer in 28 patients and none had severe complications. CONCLUSION: The combination of PDT and brachytherapy for treating patients with lung cancer and extensive endobronchial tumour is safe and, in this study, had excellent therapeutic efficacy.

Aged↗
PubMed2000

[Argon plasma coagulation in bronchology: a new method--alternative or complementary?].

Argon plasma coagulation (APC) is a thermal coagulation technique that uses ionized argon to transmit high-frequency electrical current, contact free, to tissue. APC has been used in surgery for more than 20 years, particularly for the hemostasis of superficial bleeding. Although APC has become well established in gastrointestinal endoscopy since its introduction in 1991, very few reports of its use in bronchoscopy exist to date. From June 1994 to June 1998, 364 patients (80 women, 284 men), 88% with a confirmed malignant tumor, were treated prospectively in a total of 482 sessions. The single most common indication was recanalization of malignant airway stenoses (186 patients). The defined therapy objective was achieved with good results in 67% of patients. More than 90% of interventions were performed with rigid bronchoscopy. Despite less penetration compared with Nd:YAG laser, extensive bronchial tumors were treatable, in which coagulated tumor fractions were removed either with forceps or bronchoscope tip. The second indication was bleeding in the central airways (119 patients). Acute hemostasis was achieved in 118 patients, 20% in whom the flexible technique under local anesthesia was used. In 34 patients, APC was successfully used to recanalize occluded stents. Rare indications included benign endobronchial tumor, fistula conditioning before fibrin adhesion, and the treatment of scar tissue stenosis. Summarizing all complications, a rate of 3.7% "per treatment" was recorded. Two patients died within 24 hours; their deaths were not directly related to APC. APC is an effective and safe technique for the treatment of bronchologic tumor ablation and hemostasis and can be used with local anaesthetic with flexible bronchoscopy or rigid bronchoscopy with general anesthesia. Compared with Nd:YAG laser, APC is an economic alternative technique offering more effective hemostasis. Furthermore, APC is of particular value as a compliment to well-known techniques, increasing the options in interventional bronchoscopy.

Airway Obstruction↗
PubMed1991

Slow release isosorbide-5-mononitrate therapy in angina pectoris. Effects of exercise performance and hemodynamics.

The possibility of maintaining preload reduction and enhancement of exercise tolerance during an interval treatment with 100 mg/day of slow-release isosorbide-5-mononitrate (IS-5-MN) was investigated in 12 patients (aged 57 +/- 5.0 years) with angiographically confirmed coronary artery disease and chronic stable angina pectoris. The effects of a single dose (acute test) were compared with those following an 8-day (chronic) regimen of mononitrate administration. Two hours after administration of 100 mg sustained-release IS-5-MN, mean resting pulmonary artery pressure (PAP), measured with a Swan-Ganz catheter, was reduced by 32% (p less than 0.001) and at submaximal exercise level (50 W, 3 min) by 37% (p less than 0.001). At individually highest comparable work loads mean PAP was reduced by 37% (p less than 0.001), and at maximal work load the PAP reduction was 14% (p less than 0.05). At the end of 1 week of therapy with sustained-release IS-5-MN a slight, clinically irrelevant reduction of hemodynamic effect was recorded. Work capacity increased after 1 h by 79% (264 +/- 154 vs. 472 +/- 180 W x min, p less than 0.01), still significantly above base-line 10 h after nitrate administration. No difference from baseline was demonstrable 24 h after medication. During interval therapy the improved work capacity was fully maintained (chronic, 1 h: 280 +/- 119 vs. 532 +/- 160 W x min, p less than 0.001). There was no significant difference between the plasma IS-5-MN levels at acute and chronic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

[Lack of tolerance development in interval therapy with 50 mg isosorbide-5-nitrate retard (Elantan long)].

Fluctuating mononitrate plasma levels in the course of 24 h are a prerequisite for prevention of nitrate tolerance in patients with angina pectoris undergoing longterm treatment. In 12 patients with angiographically proven coronary artery disease (54 +/- 7 years) effects of 50 mg Isosorbide-5-mononitrate (IS-5-MN) in a slow-release (SR) formulation on hemodynamics and exercise tolerance were evaluated after a first dose and at the end of a 1-week treatment period with 50 mg given once-daily. 1 and 2 h after medication mean pulmonary artery pressure (PAP) at rest was reduced by 30% (p less than 0.001) and 25% (p less than 0.01 respectively. During submaximal bicycle exercise (50 W, 3 min) PAP was significantly reduced by IS-5-MN by 35% (1 and 2 h after medication). At the end of exercise (discontinuation), drug-induced reductions of PAP were 19% (1 h) and 21% (2 h) (p less than 0.05), respectively. IS-5-MN led to a marked increase of exercise capacity (base-line: 396 +/- 119 W x min); 1 h: 646 +/- 153 W x min (p less than 0.01). At stress testing 2, 4 and 10 h post medication improvements were 67% (p less than 0.01), 49% (p less than 0.01) and 28% (p less than 0.01), respectively. 24 h after medication baseline values were reached again. After a 1-week treatment with 50 mg IS-5-MN SR daily, beneficial effects of the drug on hemodynamics and working capacity could be demonstrated. Again, significant effects could be shown up to 10 h after drug administration. Thus, IS-5-MN SR administered once daily proved effective in intermediate-term treatment of patients with coronary artery disease with regard to hemodynamics and exercise capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗