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R Hofmann

Publications and source records attributed to R Hofmann.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Detection of airborne cultivatable microorganisms from compost sites--emissions and imissions].

The statement presented here gives an overview and assessment of the procedures and concepts currently used for the collection and determination of airborne, culturable microorganisms at sources of emission within composting plants and in their near vicinity. The paper focuses on "classical" methods, which involve cultivation as an intermediate step for the determination of viable, airborne microorganisms. The theoretical and practical requirements on such methods are discussed. Results and experiences from recent investigations are described.

Air Microbiology↗
PubMed1999

['Microbial air pollutants'. Emission sources and preventive measures].

Already in the planning or monitoring phase, measures have to be realized for the reduction in emissions of bio-aerosols in biological waste treatment plants. For this purpose, operation-related measures (in open and partially closed plants) and technology-related measures (in closed plants with automatic ventilation) can be taken. A survey on the currently feasible measures for reduction is submitted. The realization has to be adapted to the individual site and type of plant. An enormous demand for examinations is envisaged in order to enable a qualified assessment of the emission behaviour of diverse waste air systems or process steps.

Air Microbiology↗
PubMed1998

Nonlinear Time&hyphenSeries Prediction with Missing and Noisy Data

We derive solutions for the problem of missing and noisy data in nonlinear time&hyphenseries prediction from a probabilistic point of view. We discuss different approximations to the solutions &hyphen in particular, approximations that require either stochastic simulation or the substitution of a single estimate for the missing data. We show experimentally that commonly used heuristics can lead to suboptimal solutions. We show how error bars for the predictions can be derived and how our results can be applied to K&hyphenstep prediction. We verify our solutions using two chaotic time series and the sunspot data set. In particular, we show that for K&hyphenstep prediction, stochastic simulation is superior to simply iterating the predictor.

Journal Article↗
PubMed1998

[Alternative endourologic methods for treatment of urethral stricture].

Advances in endoscopic instrumentation and techniques offer new alternatives for safe and effective treatment of urethral strictures. Visual internal urethrotomy, the standard treatment modality, is associated with new scar formation with stricture recurrence. This experience has led to the investigation of alternative techniques which would avoid or ameliorate this result. This article reviews the current literature and discusses these newer approaches, including balloon dilatation, laser urethrotomy, endoscopic urethroplasty, "cut to the light" and "core through" procedures, and urethral wallstent implantation.

Catheterization↗
PubMed1998

Dysfunctional voiding in women: which muscles are responsible?

OBJECTIVE: To analyse the striated external urethral sphincter (EUS) and pelvic floor muscles using two different electromyography (EMG) techniques in women with dysfunctional voiding and/or urinary retention. PATIENTS AND METHODS: Fifteen women (mean age 38.2 years, range 18-61) with dysfunctional voiding and/or unexplained voiding dysfunction associated with urinary retention were examined neurologically and urologically; urodynamics and kinesiological EMG of the bilateral pubococcygeal and external urethral striated sphincter muscles were obtained. In an additional neurophysiological session, concentric-needle EMG of the external urethral sphincter was performed. RESULTS: Kinesiological EMG recordings revealed inappropriate pelvic floor muscle activation during voiding in 11 and EUS activation in four women. Concentric needle EMG of the EUS revealed complex repetitive discharges in the four women with inappropriate urethral sphincter activation recorded by kinesiological EMG during voiding. Biofeedback training led to improvement in women with inappropriate pubococcygeal activation but not in those with urethral sphincter complex repetitive discharges. CONCLUSION: Urodynamic examinations in combination with kinesiological EMG examination of the pubococcygeal and external urethral sphincter muscles revealed two groups of women with dysfunctional voiding. Further diagnostic evaluation of such patients with concentric-needle EMG is mandatory. The differentiation of the two groups is therapeutically relevant.

Adolescent↗
PubMed1997

Sensitivity of combined DNA/immunophenotype flow cytometry for the detection of low levels of aneuploid lymphoblastic leukemia cells in bone marrow.

By simultaneous DNA staining and immunophenotyping, the aneuploid blasts of acute lymphoblastic leukemia (ALL) can be quantitated by flow cytometry. The present study evaluates the application of this method for the detection of minimal residual disease (MRD). For this purpose leukemia cells with known aneuploidy were serially diluted with diploid bone marrow cells obtained after chemotherapy. These mixed samples were immunophenotyped using antibodies CD34, CD10, or CD19 and processed for DNA staining with propidium iodide. Fifty thousand cells were measured for each experiment and the results were compared with the analysis of control sample without added aneuploid cells. Aneuploid cells diluted to 1% were not detectable in 6/15 cases when DNA content analysis was used alone, and in dilutions of < 1%, these cells were not detectable. When DNA content and immunophenotype were simultaneously measured, aneuploidy was detectable in 15/15 cases at 1.00%, 6/6 at 0.50%, 16/16 at 0.10%, and 16/17 at 0.05%. Therefore this method may be useful for the detection of minimal residual disease in cases of aneuploid lymphoblastic leukemia.

Aneuploidy↗
PubMed1997

Iridium 192 high-dose-rate brachytherapy--a useful alternative therapy for localized prostate cancer?

We report on a novel protocol involving iridium 192 high-dose-rate brachytherapy and follow-up of up to 130 months in patients with prostatic carcinoma. Using regional anesthesia, five to seven hollow needles are placed within the prostate by perineal puncture under ultrasound guidance. A 9-Gy prostate dose is applied followed by 30 min of hyperthermia (since 1991). This treatment is repeated once after 7 days; 2 weeks later, 18 x 2-Gy external beam radiation (small-field prostate) is added as percutaneous dose saturation. Since 1984 we have treated 40 patients with this protocol. Local tumor control was achieved by means of prostatic biopsy at 18 months after therapy and determination of prostate-specific antigen (PSA) values in about 70% of the patients; after a mean follow-up period of more than 6 years (16-130 months), 80% of the patients show either no evidence of disease or stable disease. We therefore conclude that iridium 192 high-dose-rate brachytherapy is a useful alternative in the treatment of localized prostate cancer in patients who are not eligible for radical prostatectomy.

Adult↗
PubMed1997

Magnetic resonance imaging in the diagnosis of acute injured distal tibiofibular syndesmosis.

RATIONALE AND OBJECTIVES: This study assessed the diagnostic potential of magnetic resonance imaging for the evaluation of the tibiofibular syndesmosis. METHODS: A total of 38 patients with an acute ankle trauma and clinical suspicion of a syndesmotic tear were prospectively studied with conventional plain film radiography and magnetic resonance imaging. Magnetic resonance imaging studies included plain T1-weighted (T1-w) and T2-weighted (T2-w) sequences and contrast-enhanced T1-w sequences 0 to 3 days after trauma. All images were read by two independent radiologists before surgical intervention. Sensitivity and specificity were determined for the two observers and the concordance of the two observers were calculated using the interobserver analysis (Kappa-Test). Intraoperative inspection (n = 21) revealed rupture of the anterior tibiofibular ligament (ATIF) in 15 patients, intact ATIF in 6 patients, and intact posterior tibiofibular ligament (PTIF) in 21 cases. Clinical and follow-up examinations revealed an intact syndesmotic complex in another 17 patients. RESULTS: Primary diagnostic criteria for diagnosing a ligamentous tear included tibiofibular diastasis in conventional plain films; nonvisualization of the ATIF; an abnormal course, a wavy, irregular contour of the ligament; increased signal intensity of the ligament in T2-w sequences, in plain T1-w sequence, and marked enhancement in T1-w after contrast. Important secondary signs were defined as joint fluid in the tibiofibular space and prolapse of interspace fat. Highest diagnostic accuracy was achieved if three or more diagnostic criteria could be visualized. Both readers performed best with the enhanced T1-weighted and the T2-weighted images in transverse orientation. The interobserver analysis resulted in high concordance: Kappa = 0.9 (confidence interval: 0.76 to 1.00) for all patients, and in Kappa = 0.76 (confidence interval: 0.45 to 1.0) for surgically treated patients. CONCLUSIONS: Magnetic resonance imaging of the syndesmotic complex is a highly sensitive and specific tool for the pretherapeutic-evaluation of syndesmotic injury.

Acute Disease↗
PubMed1997

Relative bioavailability of 3 different chlormezanone 200 mg preparations after single dose oral administration.

Eighteen male volunteers have been treated with 3 different oral formulations of chlormezanone according to a randomized 3-way change-over design. The test preparation was a tablet (Krewel), reference preparation 1 was a suspension (Krewel), and reference preparation 2 was a tablet (Muskel Trancopal, Sanofi Winthrop GmbH). All preparations contained 200 mg of chlormezanone. Divided in 3 periods the volunteers received single doses of the test and the 2 reference formulations, respectively. Blood samples have been drawn immediately prior to each administration and at 21 sampling points within 144 h after dosing. A wash-out period of 2 weeks was maintained between successive drug doses. Plasma concentrations of chlormezanone were determined by a validated reversed-phase HPLC method with UV detection, with a lower limit of quantification of 0.1 microgram/ml. The following mean values have been obtained for the test preparation: AUC0-infinity 121 micrograms x h/ml, Cmax of 2.9 micrograms/ml at 1.5 h, t1/2 38 h, after administration of the suspension: AUC0-infinity 111 micrograms x h/ml, Cmax 2.6 micrograms/ml, tmax 1.5 h, t1/2 40 h, and after administration of the reference tablet: AUC0-infinity 121 micrograms x h/ml, Cmax 3.0 micrograms/ml, tmax 1.6 h, t1/2 38 h. The test preparation shows a relative bioavailability of 109% compared to the suspension and has been proven to be bioequivalent to the reference tablet with regard to extent and rate of absorption.

Administration, Oral↗
PubMed1997

Treatment of left ventricular hypertrophy in hypertensive patients with a combination of verapamil and captopril--a multicenter study.

UNLABELLED: The regression of left ventricular hypertrophy in hypertensive patients was evaluated in a multicenter study with a combination therapy of verapamil 120 mg and captopril 25 mg given once or twice daily. The degree of left ventricular hypertrophy was assessed using echocardiography, while hypertension was evaluated by means of twice daily blood pressure self-measurements and ambulatory blood pressure monitoring. RESULTS: An overall of 61 patients was evaluated. Left ventricular mass had decreased by 13.5% during the 6-month treatment period. This reduction neither correlated with the baseline left ventricular mass nor with the extent of blood pressure decrease. CONCLUSION: The combination therapy-verapamil 120 mg plus captopril 25 mg--is well tolerated by hypertensive patients with left ventricular hypertrophy and produced a decrease of left ventricular mass that is independent of the extent of blood pressure decrease.

Adult↗
PubMed1997

[Changes in blood rheology and microcirculation after preparatory combined thrombocytapheresis and plasmapheresis].

INTRODUCTION: Because of anticoagulation, changes in blood composition, and--perhaps--extracorporeal circulation, donor apheresis should cause alterations in hemorheology and hence in the perfusion of the microvasculature. MATERIAL AND METHODS: 19 regular blood donors were included. According to our standard protocol for automated collection of blood components with the MCS 3p cell separator, we harvested 1 unit of platelets and 2 units of plasma in each case. Prior to, 1 h after, and 24 h after donation, the following parameters were measured: total serum protein (tsp), hematocrit (hc), whole blood and plasma viscosity (wbv/pv), red cell aggregability (rca) and blood flow velocity of the nail-fold capillaries (bfv). RESULTS: The following parameters decreased 1 h/24 h after donation: tsp (p < 0.001/p = 0.008), elastic wbv (p = 0.018/p < 0.001), viscous wbv (p = 0.85/p = 0.0031), pv (p < 0.001/p < 0.001), static rca (p < 0.001/p = 0.0073), dynamic rca (p < 0.001/p = 0.017). The hc showed an initial increase (p < 0.001) with a subsequent overshooting decrease after 24 h (p < 0.001). 1 h after donation bfv raised (p = 0.0065). It decreased after 24 h and remained only slightly higher than the initial level (p = 0.27). CONCLUSIONS: Automated combined collection of platelets and plasma gives rise to: i) Improvement of rheological properties of the donor's blood and increased bfv of his nail-fold capillaries within the 1st h after apheresis. ii) 24 h after donation the improved hemorheological properties remain demonstrable, but the bfv of nail-fold capillaries declines and shows a trend toward the starting-point. iii) Taken together, this is possibly reflecting adapted hemodynamic and vasoconstrictor regulation for altered hemorheological conditions.

Adaptation, Physiological↗
PubMed1996

Clinical relevance of urokinase plasminogen activator, its receptor, and its inhibitor in patients with renal cell carcinoma.

BACKGROUND: Urokinase plasminogen activator (u-PA) plays a key role in the metastatic process by promoting plasmin mediated tissue degradation. Metastatic cell invasion requires localized proteolysis, which may be directed by u-PA receptor. The binding of u-PA and PAI-1 to the u-PA-receptor may cause internalization of the trimeric complex into the cell and activate a tyrosine-kinase. In a prospective study the u-PA, u-PA-R, and PAI-1 content in patients with renal cell carcinoma (RCC) and benign renal tissue were correlated with traditional prognostic factors such as the TNM staging, histologic grading, ploidy, and the clinical outcome of the patients. METHODS: One hundred fifty-two patients who underwent transperitoneal tumor nephrectomy for RCC were followed up for a mean of 23.9 months. u-PA, u-PA-R, and PAI-1 from the tumor tissue and corresponding benign renal tissue were quantified from detergent extracted tissue samples (1% Trinton-X-100 in triethanolamine-buffered saline) and measured with an enzyme-linked immunoadsorbent assay. RESULTS: PAI-1 significantly correlated with the prevalence of distant metastasis (M0: 10.04 vs. M1 23.79, P=0.02) and the development of new metastasis postoperatively (M0: 10.85 vs. M1 27.36, P=0.001). A cut-off level of 12 ng/mg protein for PAI-1 selected a group of patients at high risk for relapse. Forty-one patients had PAI-1 > 12 ng/mg with 6 relapses compared with 55 patients with PAI-1 < 12 ng/mg with 1 relapse during the follow-up. Content of mu-PA correlated with the development of distant metastases (log rank 4.32, P=0.037). A cut-off value of 0.84 ng/mg selected 2 groups: a group at high risk for metastasizing (u-PA > 0.84, n=11 with 9 events and a group at low risk (u-PA < 0.84 with 94 patients and 5 events). Applying a cut-off value of 0.85 for u-PA-R 2 groups could be discriminated: 31 patients had no relapse with u-PA-R < 0.85 and 18 had 3 recurrences with u-PA-R > 0.85 g/ml. CONCLUSIONS: u-PA, u-PA-R, and PAI-1 are strong and independent prognostic factors for predicting early relapse for RCC. Especially with PAI-1, a high and low risk group for disease free survival can be discriminated.

Biomarkers, Tumor↗
PubMed1996

Autologous tissue cardiac valve for aortic valve replacement: technical aspects and early results.

BACKGROUND: The known complications of heterograft bioprostheses and homograft valves have renewed the interest in the use of autologous material. A new technique to construct a tissue prosthesis for aortic valve replacement using the patient's pericardium harvested at the time of operation was developed. The glutaraldehyde-tanned pericardium is mounted on a stent requiring no suturing. Intraoperative testing assures adequate valve function. METHODS: The autologous tissue cardiac valve was implanted in 50 patients in the aortic position between March 1994 and May 1995. Echocardiograms were performed in all patients before hospital discharge, at 3 months (41 patients), and at the end of first postoperative year (12 patients). The mean age was 69.8 +/- 5 years (range, 58 to 82 years). Eighty-four percent of patients presented with aortic stenosis and 16% had a combined lesion. Additional cardiac procedures were performed in 21 patients. RESULTS: Aortic cross-clamp time was 72 +/- 19 minutes, and bypass time was 97 +/- 28 minutes. There were three in-hospital deaths, and 2 patients died within the first postoperative year. Predischarge echocardiography demonstrated excellent hemodynamics, with a mean gradient of 20 +/- 8 mm Hg and no or trivial aortic insufficiency in 45 patients. One patient had moderate aortic insufficiency. At first follow-up 36 patients (90%) were in New York Heart Association class I and 4 patients were in class II. Echocardiography showed no evidence of valve failure or degeneration (mean gradient, 17 +/- 5mm Hg; aortic insufficiency = grade 0 [trivial] in 35 patients, grade II in 3 patients, and grade III in 1 patient). Similarly, no degeneration or valve failure with increasing aortic insufficiency was seen in the patients studied at the end of the first postoperative year. CONCLUSIONS: These results demonstrate that an autologous tissue cardiac valve can be manufactured in the operating room without significant additional operating time. Intraoperative testing minimizes the risk of primary failure with aortic insufficiency. Short-term results are encouraging with good hemodynamic performance of the valve and no signs of degeneration. However, long-term durability needs to be demonstrated.

Aged↗
PubMed1996

Prognostic value of urokinase plasminogen activator and plasminogen activator inhibitor-1 in renal cell cancer.

PURPOSE: Urokinase type plasminogen activator and its inhibitor plasminogen activator inhibitor are associated with invasion and formation of metastases in tumors. In a prospective study urokinase and plasminogen activator inhibitor-1 content in renal cell cancer and benign renal tissue was correlated with the traditional factors of TNM staging and grading as well as ploidy and actual clinical outcome of the patients. MATERIAL AND METHODS: A total of 152 patients, who underwent transperitoneal tumor nephrectomy for renal cell cancer, was followed for a mean of 23.9 months. Urokinase and plasminogen activator inhibitor-1 from the tumor tissue and corresponding benign renal tissue were quantified from detergent extracted tissue samples (1% triton-X = 100 in TBS) and measured with an enzyme-linked immunosorbent assay. RESULTS: Urokinase content correlated with the development of distant metastases (log rank 4.32, p = 0.037). Cutoff value was 0.84 ng/mg. A group of 11 patients were considered to be at high risk for metastases (9 events) based on urokinase greater than 0.84 ng/mg., while 94 patients were considered to be at low risk (5 events) with urokinase less than 0.84 ng/mg. Plasminogen activator inhibitor-1 significantly correlated with the prevalence of distant metastases (log rank 5.17, MO, 10.04 versus M1, 23.79, p = 0.02) and the development of new metastases postoperatively (MO, 10.85 versus M1, 27.36, p = 0.001). Cutoff value was 12 ng/mg. protein. A group of 41 patients were considered at high risk for relapse (6) based on plasminogen activator inhibitor-1 greater than 12 ng/mg. protein compared to 55 patients with plasminogen activator inhibitor-1 less than 12 ng/mg. protein with only 1 relapse during followup. CONCLUSIONS: Plasminogen activator inhibitor-1, the specific inhibitor of urokinase is a strong and independent prognostic factor in predicting early relapse of renal cell carcinoma. High and low risk groups for disease-free survival can be discriminated by plasminogen activator inhibitor-1 antigen content in the tumor tissue.

Carcinoma, Renal Cell↗
PubMed1995

Pharmacodynamic effects of St. John's Wort on rat intracerebral field potentials.

Two extracts of St. John s Wort were compared with respect to their action on in vivo monitored field potentials from four brain areas of the freely moving rat. Quantitative assessment of the drug action revealed a late onset (3 to 4 hours after oral application) and main effects on the frontal cortex. Changes consisted in electrical power alterations reminiscent of the action of antidepressive and/or analgesic drugs. Particular frequency bands affected first line were alpha1 and alpha2, which in some way are related to serotonergic and dopaminergic transmission. From this it is concluded that St. Johns Wort could be used for the indication of depression with predictable success. The extract labeled "K" turned out to be superior especially after repetitive application and could thus far be used for further studies.

Action Potentials↗